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β-Secretase (β-site amyloid precursor protein-cleaving enzyme 1; BACE1) is a transmembrane aspartic protease that cleaves the β-amyloid precursor protein en route to generation of the amyloid β-peptide (Aβ) that is believed to be responsible for the Alzheimer's disease amyloid cascade. It is thus a prime target for the development of inhibitors which may serve as drugs in the treatment and/or prevention of Alzheimer's disease. In the following determination of the crystal structures of both apo and complexed BACE1, structural analysis of all crystal structures of BACE1 deposited in the PDB and molecular dynamics (MD) simulations of monomeric and `dimeric' BACE1 were used to study conformational changes in the active-site region of the enzyme. It was observed that a flap able to cover the active site is the most flexible region, adopting multiple conformational states in the various crystal structures. Both the presence or absence of an inhibitor within the active site and the crystal packing are shown to influence the flap's conformation. An open conformation of the flap is mostly observed in the apo structures, while direct hydrogen-bonding interaction between main-chain atoms of the flap and the inhibitor is a prerequisite for the flap to adopt a closed conformation in the crystal structures of complexes. Thus, a systematic study of the conformational flexibility of the enzyme may not only contribute to structure-based drug design of BACE1 inhibitors and of other targets with flexible conformations, but may also help to better understand the mechanistic events associated with the binding of substrates and inhibitors to the enzyme. Show less

Mammalian spermatogenesis is a process whereby male germ-line stem cells (spermatogonial stem cells) divide and differentiate into sperm. Although a great deal of progress has been made in the isolation and characterization of spermatogonial stem cells (SSCs) in rodents, little is known about human SSCs. We have recently isolated human G protein-coupled receptor 125 (GPR125)-positive spermatogonia and GDNF family receptor alpha 1 (GFRA1)-positive spermatogonia using a 2-step enzymatic digestion and magnetic-activated cell sorting (MACS) from adult human testes. Cell purities of isolated human GPR125- and GFRA1-positive spermatogonia after MACS are greater than 95%, and cell viability is over 96%. The isolated GPR125- and GFRA1-positive spermatogonia coexpress GPR125, integrin, alpha 6 (ITGA6), THY1 (also known as CD90), GFRA1, and ubiquitin carboxyl-terminal esterase L1 (UCHL1), markers for rodent or pig SSCs/progenitors, suggesting that GPR125- and GFRA1-positive spermatogonia are phenotypically the SSCs in human testis. Human GPR125-positive spermatogonia can be cultured for 2 weeks with a remarkable increase in cell number. Immunocytochemistry further reveals that GPR125-positive spermatogonia can be maintained in an undifferentiated state in vitro. Collectively, the methods using enzymatic digestion and MACS can efficiently isolate and purify SSCs from adult human testis with consistent and high quality. The ability of isolating and characterizing human SSCs could provide a population of stem cells with high purity for mechanistic studies on human SSC self-renewal and differentiation as well as potential applications of human SSCs in regenerative medicine. Show less

Mucogingival conditions are deviations from the normal anatomic relationship between the gingival margin and the mucogingival junction. Mucogingival surgery is plastic surgery designed to correct defects in the gingiva surrounding the teeth. Common mucogingival conditions are recession, absence, or reduction of keratinized tissue, and probing depths extending beyond the mucogingival junction. Surgical techniques used to augment cosmetic mucogingival defects include the free gingival autograft, the subepithelial connective tissue graft, rotational flaps, lateral sliding flaps, coronally repositioned flaps, and the use of acellular dermal matrix grafts. Show less

Sugar appetite is influenced by unlearned attractions to sweet taste and learned responses to sugars' taste and post-ingestive actions. In rats, sugar-conditioned flavor preferences (CFP) are attenuated by dopamine D1 (SCH23390: SCH), but not by opioid (naltrexone: NTX), receptor antagonism. Sucrose-CFP occurs in BALB/c and SWR inbred mice that differ in their suppressive effects of SCH and NTX on sucrose intake. The present study examined whether SCH and NTX altered expression of previously learned sucrose-CFP and acquisition (learning) of sucrose-CFP in these strains. In Experiment 1, food-restricted mice were trained (10 one-bottle sessions) to drink a more-preferred flavored (e.g., cherry) 16% sucrose solution (CS+/Sucrose) on odd-numbered days, and a less-preferred flavored (e.g., grape) 0.05% saccharin solution (CS-/Saccharin) on even-numbered days. Two-bottle tests with the flavors mixed in 0.2% saccharin occurred 30 min following vehicle (Veh), SCH (50-800 nmol/kg) or NTX (1-5mg/kg) assessing preference expression. CS+ preference expression in BALB/c and SWR mice following Veh were significantly reduced by SCH and NTX. In Experiment 2, separate groups of BALB/c and SWR mice received Veh, SCH (50 nmol/kg) or NTX (1mg/kg) injections 30 min prior to daily one-bottle training sessions with the CS+/Sucrose and CS-/Saccharin solutions assessing preference acquisition. Subsequent two-bottle tests with the CS+ vs. CS- solutions were conducted without injections. CS+/Sucrose training intakes were reduced by SCH in both strains and by NTX in BALB/c mice. In the initial two-bottle test, sucrose-CFP acquisition was significantly reduced in BALB NTX (54%), but not in BALB SCH (77%) groups relative to the BALB Veh group (85%). In contrast, sucrose-CFP acquisition was significantly reduced in SWR SCH (61%), but not in SWR NTX (83%) groups relative to the SWR Veh group (86%). DA D1 and opioid receptor signaling modulate acquisition and/or expression of sucrose-CFP in mice with significant strain differences observed. Show less

Ischemic stroke is a devastating disease with a complex pathophysiology. Galangin is a natural flavonoid isolated from the rhizome of Alpina officinarum Hance, which has been widely used as an antioxidant agent. However, its effects against ischemic stroke have not been reported and its related neuroprotective mechanism has not really been explored. In this study, neurological behavior, cerebral infarct volumes and the improvement of the regional cortical blood flow (rCBF) were used to evaluate the therapeutic effect of galangin in rats impaired by middle cerebral artery occlusion (MCAO)-induced focal cerebral ischemia. Furthermore, the determination of mitochondrial function and Western blot of apoptosis-related proteins were performed to interpret the neuroprotective mechanism of galangin. The results showed that galangin alleviated the neurologic impairments, reduced cerebral infarct at 24 h after MCAO and exerted a protective effect on the mitochondria with decreased production of mitochondrial reactive oxygen species (ROS). These effects were consistent with improvements in the membrane potential level (Dym), membrane fluidity, and degree of mitochondrial swelling in a dose-dependent manner. Moreover, galangin significantly improved the reduced rCBF after MCAO. Western blot analysis revealed that galangin also inhibited apoptosis in a dose-dependent manner concomitant with the up-regulation of Bcl-2 expression, down-regulation of Bax expression and the Bax/Bcl-2 ratio, a reduction in cytochrome c release from the mitochondria to the cytosol, the reduced expression of activated caspase-3 and the cleavage of poly(ADP-ribose) polymerase (PARP). All these data in this study demonstrated that galangin might have therapeutic potential for ischemic stroke and play its protective role through the improvement in rCBF, mitochondrial protection and inhibiting caspase-dependent mitochondrial cell death pathway for the first time. Show less

Extraction of impacted teeth is one of the most common surgical procedures performed by oral and maxillofacial surgeons. Every surgical procedure results in some degree of postoperative bleeding and inflammation, typically manifesting as pain and edema. Although the complex physiology of the human body is beyond the scope of this article, the educated clinician should have an understanding of the time line associated with these processes so as to determine whether a patient's complaint of postoperative bleeding, pain, or swelling represents a normal response to surgical trauma or an aberrant reaction. Show less

Negative attitudes in health such as cigarette smoking and imbalanced diet play important role in pathogenesis of various diseases. Cigarette smoking constitutes one of the main sources of exposure to cancerogenic and procancerogenic xenobiotics among adults as well as among young people. Many studies have proven that cigarettes smokers more frequently follow less varied diet in comparison to non-smokers. Despite increasing knowledge of Poles regarding harmful effects of cigarettes smoking and numerous antinicotine campaigns, still high number of women and men smoke and the smoking percentage among young people remains high and has not decreased in the recent years. The ongoing research shows that free radicals -the man cause of exposure to oxidative stress- play the seminal role in pathogenesis of civilisation diseases and physiological cell aging processes. Reactive oxygen and nitrogen species present in cigarette smoke due to induced toxic compounds formation, are closely connected with observed increased risk of cancer, Chronic Obstructive Pulmonary Disease (COPD) and arteriosclerosis incidents. Malondialdehyde is one of the most studied product of lipid peroxidation and biomarker of oxidative stress. However, 3-nitrotyrosine is one of the most promising biomarkers regarding changes caused by oxidative stress in living organisms. The presence of 3-nitrotyrosine was observed in many diseases such as coronary artery disease, cancer and diabetes. The aim of the study was the evaluation of free radical processes increase related to tobacco smoke exposure and chosen diet habits by determination of 3-nitrotyrosine in plasma samples collected from the group of medicine students. In our investigation we used an author's questionnaire which served to estimate the exposure to tobacco smoke among medicine students. It took also into account the knowledge of the exposure to other xenobiotics and unhealthy habits/behaviours. The investigated group included 150 students of 1-st and 2-nd year of study at Faculty of Medicine and Dentistry Division in Zabrze, Silesian Medical University. 120 students provided blood samples for further analysis. In the study group 52 students were active smokers and the control group consisted of 68 non-smokers. 3-nitrotyrosine was determined with the use of ELISA technique. The mean concentration of 3-nitrotyrosine was higher in the group of smoking students in comparison to the control group. Diet habits also influenced the concentration of 3-nitrotyrosine. Eating food products of possibly high acrylamide level and drinking alcohol led in particular to observed increased concentrations of 3-nitrotyrosine in both students groups. The correlation between the food habits and the severity of nitrosative stress was also found. Show less

Smoking cigarettes and alcohol addiction are serious problems in health hazard and life of society. Tobacco smoke leads to many kinds of cancer formation and scientific research indicates, that heart-vascular disease and lung cancer are the most common diseases caused by tobacco smoke. While talking about ethanol, it is responsible for liver, pancreas, mucous membrane damage and leads to central and circular nervous disorder. Scientific research indicates, that many smokers drink alcohol and vice versa. Unfortunately in that case the risk of many diseases increases. Both of these stimulants leads to enlarged production of reactive oxygen species, which is connected with unbalance between pro and antioxidant processes in human organism. Free radicals in normal conditions plays positive role but with tobacco smoke and alcohol connection may lead to serious changes in human organism. They damage organs, it comes to protein structure, nucleic acid and fat violation, which in consequence leads to immunity decrease and many pathological changes. Reactive oxygen species also plays role in pathogenesis of many diseases: diabetes mellitus, atherosclerosis and Down syndrome. ROS may also increase the risk of pancreas, lung, larynx and urinary bladder cancer formation. Human organism defends oneself from harmful influence of reactive oxygen species owing to enzymatic and non-enzymatic systems presence-Non-enzymatic antioxidants: glutathione, carotene, bilirubin, tocopherol, uric acid and ions metals temporary complex belong to non-enzymatic systems. To enzymatic ones belong: catalase, superoxide dismutase, glutathione reductase and glutathione peroxidase. The aim of the study was tobacco smoke and ethyl alcohol influence evaluation in rats addicted to these substances on activity of chosen enzymes responsible for organism defense against toxic compounds action. To this study 63 white, Wistar tribe rats at the age of 3,5 months were used - males addicted to ethyl alcohol. They were divided into 3 groups, each consist of 21 rats. Animals of Group I were exposed on harmful tobacco smoke influence. Group II constitute animals, which were given by stomach probe 10% alcohol dilution once at a dose of 2 g/kg weight. The next Group - III, in which animals at first were exposed on tobacco smoke influence. When exposition was over, animals were given by stomach probe 10% alcohol dilution once at a dose of 2 g/kg weight. Depending on the type of marker and studied organ, changes in the levels of selected enzymes, responsible for defending organism against reactive forms of oxygen has been shown. Both tobacco smoke and ethyl alcohol resulted in a change of glutathione levels in the serum and tissues of animals. Tobacco smoke has the biggest influence on protein nitrozylation in the brain and ethyl alcohol had influence on glutathione level in serum, kidney, brain and superoxide dismutase activity in the brain. Application of many oxidative stress markers allows for evaluation of its differential influence on various organs. Show less

In recent years, the increase in the incidence of multiple sclerosis (MS - Multiple Sclerosis) is observed. and the direct cause of the symptoms of multiple sclerosis is myelin nerves damage. It can be concluded that the environmental factor is at least partly responsible for the occurrence of this disease. For the development of this disease are responsible, in addition to genetic factors, compounds present in many parts of the environment. Many of these compounds may adversely affect the redox equilibrium of the body, exacerbating radicalgenesis and decreasing antioxidant defenses. Multiple sclerosis is usually diagnosed in early adulthood, during most daily activities. Effects of SM on living standards includes not only the medical aspect, but also social, economic and emotional aspect. Polish population is a high risk zone regarding multiple sclerosis. The aim of this study was a preliminary assessment of selected environmental exposure factors in the pathogenesis of multiple sclerosis with regard to exposure to tobacco smoke with the author's survey of patients from the region of Upper Silesia. Most MS patients (32) in the study group (suffering from MS from 2 to 44 years) are inhabitants of agglomeration of over 50 thousand citizens, from the area of Gliwice, Bytom and Zabrze (43.75%). In investigated group 46.88% MS patients from Silesia region were exposed to tobacco smoke, of which 21.88% actively smoke. Patients with MS, in order not to worsen their disease manifestation, should stop smoking and increase, if possible, any physical activities. These data will be incorporated into a wide-ranging research to clarify the role of selected environmental factors in a very complex and still not fully explored the pathogenesis of multiple sclerosis in Upper Silesia. Show less

This article reviews and highlights exodontia tips as well as new techniques to make simple and complex exodontia more predictable and efficient with improved patient outcomes. A discussion of a powered periotome that has been developed to aid in the atraumatic extraction of teeth and another new device, the piezosurgery, increasingly used for outpatient oral surgery procedures are included. Physics forceps, a new type of exodontia forceps, is also discussed in this article. Show less

There have been several exciting technological advances in extraction techniques and outpatient oral surgery within the last decade. A variety of new instruments and techniques are revolutionizing the fields of oral and maxillofacial surgery and dentistry. This article reviews the newer innovations in dentistry including the powered periotome, piezosurgery, the Physics Forceps, laser therapy, orthodontic techniques, and use of polyurethane foam. Show less

Amendment to the Act on health protection against consequences of using tobacco and tobacco products, in force since 15 November 2010, has introduced a number of changes by extending the range of population protection against tobacco smoke exposure, of which the most controversial one for public was placing more restrictive ban on smoking in bars and restaurants. The changes in question caused that current legal bans, although more restrictive than earlier, are still not completely sufficient as far as the protection of all groups of workers against environmental tobacco smoke exposure is concerned. The text of WHO Framework Convention on Tobbacco Control, ratified by Poland, was discussed in the article together with the detailed WHO guidelines on the convention implementation in the field of workers' protection against tobacco smoke. In this paper the most important acts of EU, one of the convention parties, and current legislative situation in Poland were presented. Particular attention was paid to occupational groups, not yet fully protected against environmental tobacco smoke exposure and need to be the subject of future legislation. Show less

The technologic advances in temporomandibular joint arthroscopy and arthrocentesis have given oral surgeons a treatment for patients who have not responded to conservative and pharmacologic treatment without the surgical risks and long-term recovery of open joint surgery. Show less

Environmental tobacco smoke exposure (ETS) is a significant risk factor for the development of many diseases, including lung cancer, lower respiratory tract infections, asthma and eye, throat and nasal irritations. Hospitality workers form an occupational group with high exposure to ETS in their workplace. Taking into account the health consequences of ETS exposure and high prevalence of exposure in public places, including workplaces, many countries have implemented the smoking ban that prohibits or restricts smoking in workplaces, including restaurants and bars. The epidemiological studies have indicated a significant reduction in the exposure level after implementation of the smoking ban. Most studies have also indicated a significant reduction in respiratory and sensory symptoms. The impact of the smoking ban on the lung function measurements is still not clear. Show less

To perform a systematic review and meta-analysis to quantitatively assess functional magnetic resonance (MR) imaging lateralization of language function in comparison with the Wada test. This study was determined to be exempt from review by the institutional review board. A systematic review and meta-analysis were performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A structured Medline search was conducted to identify all studies that compared functional MR imaging with the Wada test for determining hemispheric language dominance prior to brain surgery. Studies meeting predetermined inclusion criteria were selected independently by two radiologists who also assessed their quality using the Quality Assessment of Diagnostic Accuracy Studies tool. Language dominance was classified as typical (left hemispheric language dominance) or atypical (right hemispheric language dominance or bilateral language representation) for each patient. A meta-analysis was then performed by using a bivariate random-effects model to derive estimates of sensitivity and specificity, with Wada as the standard of reference. Subgroup analyses were also performed to compare the different functional MR imaging techniques utilized by the studies. Twenty-three studies, comprising 442 patients, met inclusion criteria. The sensitivity and specificity of functional MR imaging for atypical language dominance (compared with the Wada test) were 83.5% (95% confidence interval: 80.2%, 86.7%) and 88.1% (95% confidence interval: 87.0%, 89.2%), respectively. Functional MR imaging provides an excellent, noninvasive alternative for language lateralization and should be considered for the initial preoperative assessment of hemispheric language dominance. Further research may help determine which functional MR methods are most accurate for specific patient populations. Show less

Y chromosome short tandem repeat (Y-STR) loci are important genetic markers for forensic biological evidence analyses. However, paternal inheritance, reduced effective population size, and lack of independence between loci can reduce Y-STR diversity and may yield greater population substructure effects on a locus-by-locus basis compared with the autosomal STR loci. Population studies are necessary to assess the genetic variation of forensically relevant markers so that proper inferences can be made about the rarity of DNA profiles. This study examined 16 Y-STRs in three sampled populations of Native Americans from Alaska: Inupiat, Yupik, and Athabaskan. Population genetic and statistical issues addressed were: (1) the degree of diversity at locus and haplotype levels, (2) determination of the loci that contribute more so to haplotype diversity, and (3) the effects of population substructure on forensic statistical calculations of the rarity of a Y-STR profile. All three population samples were highly polymorphic at the haplotype level for the 16 Y-STR markers; however, the Native Americans demonstrated reduced genetic diversity compared with major US populations. The degree of substructure indicated that the three populations were related and admixed in terms of paternal lineage. The examination of more polymorphic loci may be needed to increase the power of discrimination of Y-STR systems in these populations. Show less

Environmental tobacco smoke (ETS) exposure induces serious negative health consequences, of which the increased risk of cardiovascular diseases, cancer, respiratory symptoms and poor pregnancy outcomes appear to be most important. Taking into account those health consequences of ETS exposure most countries have introduced legislation to ban or restrict smoking in public places. In this paper the effectiveness of the introduced legislation was analyzed with regard to the protection of hospitality workers from ETS exposure in the workplace. The analysis of 12 papers published after 2000 covered the year of publication, type of legislation, study population, hospitality venue (pub, bar, restaurant, disco) and type of markers or self-reported perception of exposure to ETS. The analysis indicates that the legislation to ban smoking in hospitality venues protects workers from ETS exposure when the venues are 100% tobacco smoke free. The reduction of the cotinine level in biological samples after the implementation of smoke free law was 57-89%, comparing to the biomarker level in the samples taken before the new law was introduced. About 90% of reduction in nicotine and PM levels was also noted. In addition, the positive self perception reported by workers proved the effectiveness of new legislation protecting them from ETS exposure. Show less

A rare case of granulocytic sarcoma of the hand and palate, also known as chloroma, occurring in an adolescent patient is presented. Diagnostic clinical criteria, along with treatment pictures, are also reviewed. Show less

Lymphoma is a common disease of the head and neck. Mucosal-associated lymphoid tissue (MALT) lymphoma constitutes a rare type of extranodal lymphoma. The Waldeyer's ring is one of the most common sites of occurrence, but MALT lymphoma may also arise in salivary glands, lung, stomach, or lacrimal glands. In the oral cavity, it may be confused with swellings from dental infection or sinus inflammation. Often, the patient will seek a dentist because of mobile teeth or because a denture no longer fits. We report a case of a female patient with salivary gland dysfunction and pain of several years' duration, who, after numerous tests and hospitalizations, was diagnosed with Sjögren's syndrome. She later developed mucosal-associated lymphoid tissue lymphoma. We discuss the diagnosis, treatment, and prognosis of this entity. MALT lymphoma is rare in salivary glands. In primary-Sjögren's syndrome, predisposition of the patient for development of malignant non-Hodgkin's lymphoma (4% to 10%) is well established. In this case, long-standing sialadenitis and Sjögren's syndrome seem to be the etiological factors. In cases of chronic infection of salivary glands and the presence of autoimmune syndromes, MALT lymphoma should be considered in the differential diagnosis. Consults should be called to ophthalmology, rheumatology, and head and neck oncologists for proper workup, staging, and treatment. Show less

Dyggve-Melchior-Clausen (DMC) syndrome is a rare autosomal recessive disorder. It is a spondyloepimetaphyseal dysplasia associated with mental retardation. Clinical manifestations include coarse facies, microcephaly, short trunk dwarfism, and mental retardation. Mutations in Dymeclin gene (DYM), mapped to chromosome 18q21.1, is responsible for DMC. We report here the observation of a consanguineous Moroccan patient having DMC syndrome. The molecular studies showed a previously reported homozygous mutation at c.1878delA of DYM gene. We discuss this recurrent mutation in Moroccan patients with DMC syndrome with a review. Show less

Active and passive tobacco smoking by students of medical universities show that medical studies cannot be an effective barrier against continuing or even commencing smoking. The aim of the study was an evaluation of tobacco smoking and passive exposure to environmental tobacco smoke in the Physiotherapy students of Faculty of Military Medicine Medical University of Lodz. There were 565 Physiotherapy students of between 1-5th year of studies, including 394 women and 171 men (mean age 22.41), who were covered by the questionnaire research. The author's form of the questionnaire consisted of closed questions about demographic data and data on active and passive smoking. Prior to completing the questionnaire each student signed an informed consent as well as had an opportunity to get familiar with the patient's information form and could ask additional questions. The results analysis of the questionnaire indicated that 21.42% of the studied subjects are active smokers whereas 78.58% - non-smokers. No statistically significant differences in tobacco smoking due to sex have been noticed. The highest percentage of smokers was found on the 2nd and 3rd year of studies. In the group of 444 non-smokers there were as many as 67.1% of passive smokers. Tobacco smoking rate among Physiotherapy students amounts to 21.42% and is lower than the rate observed in the Polish population. Among non-smoking physiotherapy students there are 67.1% who are exposed to secondhand tobacco smoke. The obtained result does not largely stray from the result for the adult Polish population. Show less

During sporulation, Bacillus thuringiensis subsp. israelensis produces a mosquito larvicidal protein complex containing several crystalline and cytolytic (Cyt) toxins. Here, the activated monomeric form of Cyt1Aa, the most toxic Cyt family member, was isolated and crystallized, and its structure was determined for the first time at 2.2 Å resolution. Cyt1Aa adopts a typical cytolysin fold containing a β-sheet held by two surrounding α-helical layers. The absence of a β-strand (between residues V26 and I37) in the dimeric structure of Cyt2Aa led us to deduce that this is the only essential segment for dimer formation and that activation of the toxin occurs by proteolytic processing of its N-terminus. Based on the Cyt1Aa structure, we suggest that the toxicity of Cyt1Aa and other nonrelated proteins, all sharing a cytolysin fold, is correlated with their ability to undergo conformational changes that are necessary prior to their membrane insertion and perforation. This fold allows the α-helical layers to swing away, exposing the β-sheet to insert into the membrane. The identification of a putative lipid binding pocket between the β-sheet and the helical layer of Cyt1Aa supports this mechanism. Sequence-based structural analysis of Cyt1Aa revealed that the lack of activity of Cyt1Ca may be related to the latter's inability to undergo this conformational change due to its lack of flexibility. The pattern of the hemolytic activity of Cyt1Aa presented here (resembling that of pore-forming agents), while differing from that imposed by ionic and nonionic detergents, further supports the pore-forming model by which conformational changes occur prior to membrane insertion and perforation. Show less

Selective estrogen receptor modulators, such as 17β-estradiol derivatives bound to metal complexes, have been synthesized as targeted probes for the diagnosis and treatment of breast cancer. Here, we report the detailed 3D structure of estrogen receptor α ligand-binding domain (ERα-LBD) bound with a novel estradiol-derived metal complex, estradiol-pyridine tetra acetate europium(III), at 2.6 Å resolution. This structure provides important information pertinent to the design of novel functional ERα targeted probes for clinical applications. Show less

Endogenous tissue inhibitors of metalloproteinases (TIMPs) have key roles in regulating physiological and pathological cellular processes. Imitating the inhibitory molecular mechanisms of TIMPs while increasing selectivity has been a challenging but desired approach for antibody-based therapy. TIMPs use hybrid protein-protein interactions to form an energetic bond with the catalytic metal ion, as well as with enzyme surface residues. We used an innovative immunization strategy that exploits aspects of molecular mimicry to produce inhibitory antibodies that show TIMP-like binding mechanisms toward the activated forms of gelatinases (matrix metalloproteinases 2 and 9). Specifically, we immunized mice with a synthetic molecule that mimics the conserved structure of the metalloenzyme catalytic zinc-histidine complex residing within the enzyme active site. This immunization procedure yielded selective function-blocking monoclonal antibodies directed against the catalytic zinc-protein complex and enzyme surface conformational epitopes of endogenous gelatinases. The therapeutic potential of these antibodies has been demonstrated with relevant mouse models of inflammatory bowel disease. Here we propose a general experimental strategy for generating inhibitory antibodies that effectively target the in vivo activity of dysregulated metalloproteinases by mimicking the mechanism employed by TIMPs. Show less

Technological advancement in bone grafting procedures using purified proteins or stem cells to induce osteogenesis is a significant contribution to patient care. Patients who would otherwise not have been suitable candidates for major autologous bone grafting procedures can continue to benefit from implant reconstruction, with a less debilitating bone reconstructive procedure. Show less

The de novo design of protein-protein interfaces is a stringent test of our understanding of the principles underlying protein-protein interactions and would enable unique approaches to biological and medical challenges. Here we describe a motif-based method to computationally design protein-protein complexes with native-like interface composition and interaction density. Using this method we designed a pair of proteins, Prb and Pdar, that heterodimerize with a Kd of 130 nM, 1000-fold tighter than any previously designed de novo protein-protein complex. Directed evolution identified two point mutations that improve affinity to 180 pM. Crystal structures of an affinity-matured complex reveal binding is entirely through the designed interface residues. Surprisingly, in the in vitro evolved complex one of the partners is rotated 180° relative to the original design model, yet still maintains the central computationally designed hotspot interaction and preserves the character of many peripheral interactions. This work demonstrates that high-affinity protein interfaces can be created by designing complementary interaction surfaces on two noninteracting partners and underscores remaining challenges. Show less

Dyggve-Melchior-Clausen syndrome (DMC), a severe autosomal recessive skeletal disorder with mental retardation, is caused by mutation of the gene encoding Dymeclin (DYM). Employing patient fibroblasts with mutations characterized at the genomic and, for the first time, transcript level, we identified profound disruption of Golgi organization as a pathogenic feature, resolved by transfection of heterologous wild-type Dymeclin. Collagen targeting appeared defective in DMC cells leading to near complete absence of cell surface collagen fibers. DMC cells have an elevated apoptotic index (P< 0.01) likely due to a stress response contingent upon Golgi-related trafficking defects. We performed spatiotemporal mapping of Dymeclin expression in zebrafish embryos and identified high levels of transcript in brain and cartilage during early development. Finally, in a chondrocyte cDNA library, we identified two novel secretion pathway proteins as Dymeclin interacting partners: GOLM1 and PPIB. Together these data identify the role of Dymeclin in secretory pathways essential to endochondral bone formation during early development. Show less