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Recent reports have demonstrated that adult cells can be reprogrammed to pluripotency, but mostly with genes delivered using retroviruses. Some of the genes are cancer causing; thus, these adult-derived embryonic stem (ES)-like cells cannot be used for therapy to cure human diseases. Remarkably, it has also been demonstrated recently by several groups that, in mice, spermatogonial stem cells (SSCs) can be reprogrammed to ES-like cells without the necessity of exogenously added genes. SSCs constitute one of the most important stem cell systems in the body, not only because they produce spermatozoa that transmit genetic information from generation to generation, but also because of the recent studies showing their remarkable plasticity. Very little is known about SSCs in humans, except for the earlier work of Clermont and colleagues who demonstrated that there are A(dark) and A(pale) spermatogonia, with the A(dark) referred to as the reserve stem cells and the A(pale) being the renewing stem cells. We now demonstrate that G protein-coupled receptor 125 (GPR125) may be a marker for human SSCs. Putative human SSCs can also be reprogrammed to pluripotency. We were able to achieve this result without the addition of genes, suggesting that human SSCs have considerable potential for cell-based, autologous organ regeneration therapy for various diseases. Show less

Preference and intake of sucrose varies across inbred and outbred strains of mice. Pharmacological analyses revealed that the greatest sensitivity to naltrexone-induced inhibition of sucrose (10%) intake was observed in C57BL10/J and C57BL/6J strains, whereas 129P3/J, SWR/J and SJL/J strains displayed far less sensitivity to naltrexone-induced inhibition of sucrose intake. Given that dopamine D1 (SCH23390) and D2 (raclopride) receptor antagonism potently reduce sucrose intake in outbred rat and mouse strains, the present study examined the possibility of genetic variance in the dose-dependent (50-1600 nmol/kg) and time-dependent (5-120 min) effects of these antagonists upon sucrose (10%) intake in the eight inbred (BALB/cJ, C3H/HeJ, C57BL/6J, C57BL/10J, DBA/2J, SJL/J, SWR/J and 129P3/J) and one outbred (CD-1) mouse strains previously tested with naltrexone. SCH23390 significantly reduced sucrose intake across all five doses in 129P3/J and SJL/J mice, across four doses in C57BL/6J and BALB/cJ mice, across three doses in DBA/2J, SWR/J, C3H/HeJ and C57BL/10J mice, but only at the two highest doses in CD-1 mice. SCH23390 was 2-3-fold more potent in inhibiting sucrose intake in 129P3/J and SJL/J mice relative to CD-1 mice. In contrast, only the highest equimolar 1600 nmol/kg dose of raclopride significantly reduced sucrose intake in the BALB/cJ, C3H/HeJ, C57BL/6J, C57BL/10J, DBA/2J, SJL/J and 129P3/J, but not the SWR/J and CD-1 strains. The present and previous data demonstrate specific and differential patterns of genetic variability in inhibition of sucrose intake by dopamine and opioid antagonists, suggesting that distinct neurochemical mechanisms control sucrose intake across different mouse strains. Show less

To characterize the molecular phenotype of spermatogonial stem cells (SSCs), we examined genes that are differentially expressed in the stem/progenitor spermatogonia compared to nonstem spermatogonia. We isolated type A spermatogonia (stem and nonstem type A) from 6-day-old mice using sedimentation velocity at unit gravity and further selected the stem/progenitor cell subpopulation by magnetic activated cell sorting with an antibody to GDNF-receptor-alpha-1 (GFRA1). It has been previously shown that GFRA1 is expressed in SSCs and is required for their stemness. The purity of the isolated cells was approximately 95% to 99% as indicated by immunocytochemistry using anti-GFRA1. Comparison of GFRA1-positive and GFRA1-negative spermatogonia by microarray analysis revealed 99 known genes and 12 uncharacterized transcripts that are overexpressed in the former cell population with a >2-fold change. Interestingly, the highest level of overexpression was observed for Csf1r, encoding the receptor for macrophage colony-stimulating factor (M-CSF, official symbol CSF1), which has a well-established role in the regulation of myeloid progenitor cells. Analysis of our microarray data with a bioinformatics software program (Ingenuity Systems) revealed the potential role of various signaling pathways in stem/progenitor spermatogonia and suggested a common pathway for GFRA1 and CSF1R that may lead to their proliferation. Further investigation to test this hypothesis has shown that CSF1 promotes cell proliferation in primary cultures of the isolated type A spermatogonia and in the spermatogonial-derived stem cell line C18-4. Semiquantitative RT-PCR and immunohistochemistry confirmed the previously mentioned microarray data. Collectively, this study provides novel molecular signatures for stem/progenitor spermatogonia and demonstrates a role for CSF1/CSF1R signaling in regulating their proliferation. Show less

Historians have assumed that alchemy had a close association with mining, but exactly how and why miners were interested in alchemy remains unclear. This paper argues that alchemical theory began to be synthesised with classical and Christian theories of the earth in mining books after 1500, and served an important practical function. The theory of metals that mining officials addressed spoke of mineral vapours (Witterungen) that left visible markings on the earth's surface. The prospector searched for mineral ore in part by studying these indications. Mineral vapours also explained the functioning of the dowsing rod, which prospectors applied to the discovery of ore. Historians of early chemistry and mining have claimed that mining had a modernising influence by stripping alchemy of its theoretical component, but this paper shows something quite to the contrary: mining officials may have been sceptical of the possibility of artificial transmutation, but they were interested in a theory of the earth that could translate into prospecting knowledge. Show less

DAP5/p97 (death-associated protein 5) is a member of the eukaryotic translation initiation factor 4G family. It functions as a scaffold protein promoting cap-independent translation of proteins. During apoptosis, DAP5/p97 is cleaved by caspases at position 792, yielding an 86-kDa C-terminal truncated isoform (DAP5/p86) that promotes translation of several mRNAs mediated by an internal ribosome entry site. In this study, we report the crystal structure of the C-terminal region of DAP5/p97 extending between amino acids 730 and 897. This structure consists of four HEAT-Repeats and is homologous to the C-terminal domain of eIF4GI, eIF5, and eIF2Bepsilon. Unlike the other proteins, DAP5/p97 lacks electron density in the loop connecting alpha3 and alpha4, which harbors the caspase cleavage site. Moreover, we observe fewer interactions between these two helices. Thus, previous mapping of this site by mutation analysis is confirmed here by the resolved structure of the DAP5/p97 C-terminus. In addition, we identified the position of two conserved aromatic and acidic boxes in the structure of the DAP5/p97 C-terminus. The acidic residues in the two aromatic and acidic boxes form a continuous negatively charged patch, which is suggested to make specific interactions with other proteins such as eIF2beta. The caspase cleavage of DAP5/p97 removes the subdomain carrying acidic residues in the AA-box motif, which may result in exposure of a hydrophobic surface. These intriguing structural differences between the two DAP5 isoforms suggest that they have different interaction partners and, subsequently, different functions. Show less

Agrobacterium tumefaciens infects its plant hosts by a mechanism of horizontal gene transfer. This capability has led to its widespread use in artificial genetic transformation. In addition to DNA, the bacterium delivers an abundant ssDNA binding protein, VirE2, whose roles in the host include protection from cytoplasmic nucleases and adaptation for nuclear import. In Agrobacterium, VirE2 is bound to its acidic chaperone VirE1. When expressed in vitro in the absence of VirE1, VirE2 is prone to oligomerization and forms disordered filamentous aggregates. These filaments adopt an ordered solenoidal form in the presence of ssDNA, which was characterized previously by electron microscopy and three-dimensional image processing. VirE2 coexpressed in vitro with VirE1 forms a soluble heterodimer. VirE1 thus prevents VirE2 oligomerization and competes with its binding to ssDNA. We present here a crystal structure of VirE2 in complex with VirE1, showing that VirE2 is composed of two independent domains presenting a novel fold, joined by a flexible linker. Electrostatic interactions with VirE1 cement the two domains of VirE2 into a locked form. Comparison with the electron microscopy structure indicates that the VirE2 domains adopt different relative orientations. We suggest that the flexible linker between the domains enables VirE2 to accommodate its different binding partners. Show less

The Cyt family of proteins consists of delta-endotoxins expressed during sporulation of several subspecies of Bacillus thuringiensis. Its members possess insecticidal, hemolytic, and cytolytic activities through pore formation and attract attention due to their potential use as vehicles for targeted membrane destruction. The delta-endotoxins of subsp. israelensis include three Cyt species: a major Cyt1Aa and two minor proteins, Cyt2Ba and Cyt1Ca. A cleaved Cyt protein that lacks the N- and C-terminal segments forms a toxic monomer. Here, we describe the crystal structure of Cyt2Ba, cleaved at its amino and carboxy termini by bacterial endogenous protease(s). Overall, its fold resembles that of the previously described volvatoxin A2 and the nontoxic form of Cyt2Aa. The structural similarity between these three proteins may provide information regarding the mechanism(s) of membrane-perforating toxins. Show less

Most high throughput structural proteomics centers use the sitting-drop method to obtain diffracting crystals for three-dimensional (3D) structure determination of biological macromolecules by x-ray crystallography. Although several robotic systems are available for dispensing the initial sitting-drop screening conditions, generally they are not used for optimization of crystallization conditions. This chapter describes a protocol for such automated systems, which permits easy construction of pH optimization grids using any desired fixed buffer set with varying ionic strengths directly dispensed into the crystallization plate. Show less

Under the Health Insurance Portability and Accountability Act (HIPAA) of 1996, all dental offices are required to formulate policies and procedures to ensure and secure patient privacy of health information. This article reviews the essential points of such a plan and makes recommendations for implementation. Show less

Modern dental offices must be equipped to initiate prompt emergency care should the sudden need arise. With the elderly population in dental practices increasing, these emergencies will undoubtedly occur. This article discusses the basic emergency equipment the average dental office should possess to allow for an adequate initial response. It also discusses the policies and personnel needed for dealing with emergencies. Among the basic emergency equipment, an office should have syringes, an Ambu bag, a portable oxygen system, a sphygmomanometer (child and adult sizes), and an EKG/defibrillator. Emergency drugs that should be stocked include aromatic ammonia, aspirin, and nitroglycerine. The dentist should also develop a protocol and policy for his/her staff to follow when a medical emergency arise. Show less

Malpractice litigation is part of everyday clinical practice and is an area of which all dentists need to be aware. With proper forethought and planning, this vexing issue can be controlled and made less anxiety producing. The astute clinician must be as diligent in risk-reduction management and strategies as he/she is in practicing excellent dentistry. This article discusses various preventive measures that can be used to help mitigate malpractice claims and preclude them from developing. Good patient communication, rapport, and excellent documentation are the keys to minimizing, and possibly eliminating future lawsuits. Show less

Antizyme inhibitor (AzI) regulates cellular polyamine homeostasis by binding to the polyamine-induced protein, Antizyme (Az), with greater affinity than ornithine decarboxylase (ODC). AzI is highly homologous to ODC but is not enzymatically active. In order to understand these specific characteristics of AzI and its differences from ODC, we determined the 3D structure of mouse AzI to 2.05 A resolution. Both AzI and ODC crystallize as a dimer. However, fewer interactions at the dimer interface, a smaller buried surface area, and lack of symmetry of the interactions between residues from the two monomers in the AzI structure suggest that this dimeric structure is nonphysiological. In addition, the absence of residues and interactions required for pyridoxal 5'-phosphate (PLP) binding suggests that AzI does not bind PLP. Biochemical studies confirmed the lack of PLP binding and revealed that AzI exists as a monomer in solution while ODC is dimeric. Our findings that AzI exists as a monomer and is unable to bind PLP provide two independent explanations for its lack of enzymatic activity and suggest the basis for its enhanced affinity toward Az. Show less

The design of new enzymes for reactions not catalysed by naturally occurring biocatalysts is a challenge for protein engineering and is a critical test of our understanding of enzyme catalysis. Here we describe the computational design of eight enzymes that use two different catalytic motifs to catalyse the Kemp elimination-a model reaction for proton transfer from carbon-with measured rate enhancements of up to 10(5) and multiple turnovers. Mutational analysis confirms that catalysis depends on the computationally designed active sites, and a high-resolution crystal structure suggests that the designs have close to atomic accuracy. Application of in vitro evolution to enhance the computational designs produced a >200-fold increase in k(cat)/K(m) (k(cat)/K(m) of 2,600 M(-1)s(-1) and k(cat)/k(uncat) of >10(6)). These results demonstrate the power of combining computational protein design with directed evolution for creating new enzymes, and we anticipate the creation of a wide range of useful new catalysts in the future. Show less

Ankylosing spondylitis (AS) is a systemic inflammatory disorder with frequent spinal axis symptoms. In this paper, the authors explored the spinal manifestations of AS and its characteristic anatomical lesions, radiological findings, and complications. They also offer a comprehensive report of the medical and surgical treatments with a focus on deformity correction. Show less

Analysis of the three-dimensional structures of two closely related thermophilic and hyperthermophilic alcohol dehydrogenases (ADHs) from the respective microorganisms Entamoeba histolytica (EhADH1) and Thermoanaerobacter brockii (TbADH) suggested that a unique, strategically located proline residue (Pro275) at the center of the dimerization interface might be crucial for maintaining the thermal stability of TbADH. To assess the contribution of Pro275 to the thermal stability of the ADHs, we applied site-directed mutagenesis to replace Asp275 of EhADH1 with Pro (D275P-EhADH1) and conversely Pro275 of TbADH with Asp (P275D-TbADH). The results indicate that replacing Asp275 with Pro significantly enhances the thermal stability of EhADH1 (DeltaT(1/2) Show less

In selecting a method to produce a recombinant protein, a researcher is faced with a bewildering array of choices as to where to start. To facilitate decision-making, we describe a consensus 'what to try first' strategy based on our collective analysis of the expression and purification of over 10,000 different proteins. This review presents methods that could be applied at the outset of any project, a prioritized list of alternate strategies and a list of pitfalls that trip many new investigators. Show less

Glial cell line-derived neurotrophic factor (GDNF) plays a crucial role in regulating the proliferation of spermatogonial stem cells (SSC). The signaling pathways mediating the function of GDNF in SSC remain unclear. This study was designed to determine whether GDNF signals via the Ras/ERK1/2 pathway in the C18-4 cells, a mouse SSC line. The identity of this cell line was confirmed by the expression of various markers for germ cells, proliferating spermatogonia, and SSC, including GCNA1, Vasa, Dazl, PCNA, Oct-4, GFRalpha1, Ret, and Plzf. Western blot analysis revealed that GDNF activated Ret tyrosine phosphorylation. All 3 isoforms of Shc were phosphorylated upon GDNF stimulation, and GDNF induced the binding of the phosphorylated Ret to Shc and Grb2 as indicated by immunoprecipitation and Western blotting. The active Ras was induced by GDNF, which further activated ERK1/2 phosphorylation. GDNF stimulated the phosphorylation of CREB-1, ATF-1, and CREM-1, and c-fos transcription. Notably, the increase in ERK1/2 phosphorylation, c-fos transcription, bromodeoxyuridine incorporation, and metaphase counts induced by GDNF, was completely blocked by pretreatment with PD98059, a specific inhibitor for MEK1, the upstream regulator of ERK1/2. GDNF stimulation eventually upregulated cyclin A and CDK2 expression. Together, these data suggest that GDNF induces CREB/ATF-1 family member phosphorylation and c-fos transcription via the Ras/ERK1/2 pathway to promote the proliferation of SSC. Unveiling GDNF signaling cascades in SSC has important implications in providing attractive targets for male contraception as well as for the regulation of stem cell renewal vs. differentiation. Show less

Spermatogenesis is the process by which spermatogonial stem cells divide and differentiate into sperm. The role of growth factor receptors in regulating self-renewal and differentiation of spermatogonial stem cells remains largely unclear. This study was designed to examine Gfra1 receptor expression in immature and adult mouse testes and determine the effects of Gfra1 knockdown on the proliferation and differentiation of type A spermatogonia. We demonstrated that GFRA1 was expressed in a subpopulation of spermatogonia in immature and adult mice. Neither Gfra1 mRNA nor GFRA1 protein was detected in pachytene spermatocytes and round spermatids. GFRA1 and POU5F1 (also known as OCT4), a marker for spermatogonial stem cells, were co-expressed in a subpopulation of type A spermatogonia from 6-day-old mice. In addition, the spermatogonia expressing GFRA1 exhibited a potential for proliferation and the ability to form colonies in culture, which is a characteristic of stem cells. RNA interference assays showed that Gfra1 small interfering RNAs (siRNAs) knocked down the expression of Gfra1 mRNA and GFRA1 protein in type A spermatogonia. Notably, the reduction of Gfra1 expression by Gfra1 siRNAs induced a phenotypic differentiation, as evidenced by the elevated expression of KIT, as well as the decreased expression of POU5F1 and proliferating cell nuclear antigen (PCNA). Furthermore, Gfra1 silencing resulted in a decrease in RET phosphorylation. Taken together, these data indicate that Gfra1 is expressed dominantly in mouse spermatogonial stem cells and that Gfra1 knockdown leads to their differentiation via the inactivation of RET tyrosine kinase, suggesting an essential role for Gfra1 in spermatogonial stem cell regulation. Show less

Gaucher's disease, a lysosomal storage disorder caused by mutations in the gene encoding glucocerebrosidase (GCD), is currently treated by enzyme replacement therapy using recombinant GCD (Cerezyme) expressed in Chinese hamster ovary (CHO) cells. As complex glycans in mammalian cells do not terminate in mannose residues, which are essential for the biological uptake of GCD via macrophage mannose receptors in human patients with Gaucher's disease, an in vitro glycan modification is required in order to expose the mannose residues on the glycans of Cerezyme. In this report, the production of a recombinant human GCD in a carrot cell suspension culture is described. The recombinant plant-derived GCD (prGCD) is targeted to the storage vacuoles, using a plant-specific C-terminal sorting signal. Notably, the recombinant human GCD expressed in the carrot cells naturally contains terminal mannose residues on its complex glycans, apparently as a result of the activity of a special vacuolar enzyme that modifies complex glycans. Hence, the plant-produced recombinant human GCD does not require exposure of mannose residues in vitro, which is a requirement for the production of Cerezyme. prGCD also displays a level of biological activity similar to that of Cerezyme produced in CHO cells, as well as a highly homologous high-resolution three-dimensional structure, determined by X-ray crystallography. A single-dose toxicity study with prGCD in mice demonstrated the absence of treatment-related adverse reactions or clinical findings, indicating the potential safety of prGCD. prGCD is currently undergoing clinical studies, and may offer a new and alternative therapeutic option for Gaucher's disease. Show less

Spermatogonial stem cells are required for the initiation of spermatogenesis and the continuous production of sperm. In addition, they can acquire pluripotency and differentiate into derivatives of the three embryonic germ layers when cultured in the appropriate conditions. Therefore, understanding the signaling pathways that lead to self-renewal or differentiation of these cells is of paramount importance for the treatment of infertility, the development of male contraceptives, the treatment of testicular cancers, and ultimately for tissue regeneration. In this report, we studied some of the signaling pathways triggered by glial cell line-derived neurotrophic factor (GDNF), a component of the spermatogonial stem cell niche produced by the somatic Sertoli cells. As model systems, we used primary cultures of mouse spermatogonial stem cells, a mouse spermatogonial stem cell line and freshly isolated testicular tubules. We report here that GDNF promotes spermatogonial stem cell proliferation through activation of members of the Src kinase family, and that these kinases exert their action through a PI3K/Akt-dependent pathway to up-regulate N-myc expression. Thus, to proliferate, spermatogonial stem cells activate mechanisms that are similar to the processes observed in brain stem cells and lung progenitors. Show less

The study of genetic variance in opioid receptor antagonism of sucrose and other forms of sweet intake has been limited to reductions in sweet intake in mice that are opioid receptor-deficient or lacking either pre-pro-enkephalin or beta-endorphin. Marked genetic variance in inbred mouse strains has been observed for sucrose intake across a wide array of concentrations in terms of sensitivity, magnitude, percentages of kilocalories consumed as sucrose and compensatory chow intake. The present study examined potential genetic variance in systemic naltrexone's dose-dependent (0.01-5 mg/kg) and time-dependent (5-120 min) ability to decrease sucrose (10%) intake in eleven inbred (A/J, AKR/J, BALB/cJ, CBA/J, C3H/HeJ, C57BL/6J, C57BL/10J, DBA/2J, SJL/J, SWR/J, 129P3/J) and one outbred (CD-1) mouse strains. A minimum criterion sucrose intake (1 ml) under vehicle treatment, designed to avoid "floor effects" of antagonist treatment was not achieved in three (A/J, AKR/J, CBA/J) inbred mouse strains. Marked genetic variance in naltrexone's ability to inhibit sucrose intake was observed in the remaining strains with the greatest sensitivity observed in the C57BL/10J and C57BL/6J strains, intermediate sensitivity in BALB/cJ, C3H/HeJ, CD-1 and DBA/2J mice, and the least sensitivity in 129P3/J, SWR/J and SJL/J strains with a 7.5-36.5 fold range of greater effects in the ID(50) of naltrexone-induced inhibition in C57BL/10J relative to the three less-sensitive strains across the time course. Naltrexone primarily affected the maintenance, rather than the initiation of intake in BALB/cJ, CD-1, C3H/HeJ, DBA/2J and SJL/J mice, but significantly reduced sucrose intake at higher doses across the time course in C57BL/6J, C57BL/10J and 129P3/J mice. Whereas SWR/J mice failed to display any significant reduction in sucrose intake at any time point following any of the naltrexone doses, naltrexone's maximal magnitude of inhibitory effects was small (35-40%) in 129P3/J and SJL/J mice, moderate ( approximately 50%) in BALB/cJ, C3H/HeJ, CD-1 and DBA2/J mice, and profound (70-80%) in C57BL/6J and C57BL/10J mice. Indeed, the latter two strains displayed significantly greater percentages of naltrexone-induced inhibition of sucrose intake than virtually all other strains. These data indicate the importance of genetic variability in opioid modulation of sucrose intake. Show less

Proteins bind one another in aqua's solution to form tight and specific complexes. Previously we have shown that this is achieved through the modular architecture of the interaction network formed by the interface residues, where tight cooperative interactions are found within modules but not between them. Here we extend this study to cover the entire interface of TEM1 beta-lactamase and its protein inhibitor BLIP using an improved method for deriving interaction maps based on REDUCE to add hydrogen atoms and then by evaluating the interactions using modifications of the programs PROBE, NCI and PARE. An extensive mutagenesis study of the interface residues indeed showed that each module is energetically independent on other modules, and that cooperativity is found only within a module. By solving the X-ray structure of two interface mutations affecting two different modules, we demonstrated that protein-protein binding occur via the structural reorganization of the binding modules, either by a "lock and key" or an induced fit mechanism. To explain the cooperativity within a module, we performed multiple-mutant cycle analysis of cluster 2 resulting in a high-resolution energy map of this module. Mutant studies are usually done in reference to alanine, which can be regarded as a deletion of a side-chain. However, from a biological perspective, there is a major interest to understand non-Ala substitutions, as they are most common. Using X-ray crystallography and multiple-mutant cycle analysis we demonstrated the added complexity in understanding non-Ala mutations. Here, a double mutation replacing the wild-type Glu,Tyr to Tyr,Asn on TEM1 (res id 104,105) caused a major backbone structural rearrangement of BLIP, changing the composition of two modules but not of other modules within the interface. This shows the robustness of the modular approach, yet demonstrates the complexity of in silico protein design. Show less

Analysis of the three-dimensional structures of three closely related mesophilic, thermophilic, and hyperthermophilic alcohol dehydrogenases (ADHs) from the respective microorganisms Clostridium beijerinckii (CbADH), Entamoeba histolytica (EhADH1), and Thermoanaerobacter brockii (TbADH) suggested that a unique, strategically located proline residue (Pro100) might be crucial for maintaining the thermal stability of EhADH1. To determine whether proline substitution at this position in TbADH and CbADH would affect thermal stability, we used site-directed mutagenesis to replace the complementary residues in both enzymes with proline. The results showed that replacing Gln100 with proline significantly enhanced the thermal stability of the mesophilic ADH: DeltaT(1/2) (60 min) = + 8 degrees C (temperature of 50% inactivation after incubation for 60 min), DeltaT(1/2) (CD) = +11.5 degrees C (temperature at which 50% of the original CD signal at 218 nm is lost upon heating between 30 degrees and 98 degrees C). A His100 --> Pro substitution in the thermophilic TbADH had no effect on its thermostability. An analysis of the three-dimensional structure of the crystallized thermostable mutant Q100P-CbADH suggested that the proline residue at position 100 stabilized the enzyme by reinforcing hydrophobic interactions and by reducing the flexibility of a loop at this strategic region. Show less

Genetic variation across inbred and outbred mouse strains have been observed for intake of sweet solutions, salts, bitter tastants and a high-fat diet. Our laboratory recently reported marked strain differences in the amounts and/or percentages of kilocalories of sucrose consumed among 11 inbred and one outbred mouse strains exposed to a wide range of nine sucrose concentrations (0.0001-5%) in two-bottle 24-h preference tests. To assess whether differences in fat intake were similarly associated with genetic variation, the present study examined intake of chow, water and an emulsified fat source (Intralipid) across nine different concentrations (0.00001-5%) in the same 11 inbred and 1 outbred mouse strains using two-bottle 24-h preference tests, which controlled for Intralipid concentration presentation effects, Intralipid and water bottle positions, and measurement of kilocalorie intake consumed as Intralipid or chow. Strains displayed differential increases in Intralipid intake relative to corresponding water with significant effects observed at the seven (BALB/cJ: 0.001% threshold sensitivity), four (AKR/J, C57BL/6J, DBA/2J, SWR/J: 0.5% threshold sensitivity), three (CD-1, C57BL/10J, SJL/J: 1% threshold sensitivity) and two (A/J, CBA/J, C3H/HeJ, 129P3/J: 2% threshold sensitivity) highest concentrations. In assessing the percentage of kilocalories consumed as Intralipid, SWR/J mice consumed significantly more at the three highest concentrations to a greater degree than BALB/cJ, C57BL/6J, CD-1, C3H/HeJ, DBA/J and 129P3/J strains which in turn consumed more than A/J, AKR/J, CBA/J, C57BL/10J and SJL/J mice. Relatively strong (h2 = 0.73-0.79) heritability estimates were obtained for weight-adjusted Intralipid intake at those concentrations (0.001-1%) that displayed the largest strain-specific effects in sensitivity to Intralipid. The identification of strains with diverging abilities to regulate kilocalorie intake when presented with high Intralipid concentrations may lead to the successful mapping of genes related to hedonics and obesity. Show less

Malnutrition in the oral and maxillofacial surgery surgical patient can have critical implications in the overall well-being and prognosis of the long-term, hospitalized, ill patient. The OMS should be capable of assessing the patient's nutritional status and nutritional requirements and developing appropriate recommendations for proper nutritional management. Knowledge of the various modalities of nutritional support should be readily available to the OMS practitioner. Show less

Negative feedback is among the key mechanisms for regulating receptor tyrosine kinase (RTK) signaling. Human Sef, a recently identified inhibitor of RTK signaling, encodes different isoforms, including a membrane spanning (hSef-a) and a cytosolic (hSef-b) isoform. Previously, we reported that hSef-b inhibited fibroblast proliferation and prevented the activation of mitogen-activated protein kinase (MAPK), without affecting protein kinase B/Akt or p38 MAPK. Conflicting results were reported concerning hSef-a inhibition of MAPK activation, and the effect of hSef-a on other RTK-induced signaling pathways is unknown. Here we show that, in fibroblasts, similar to hSef-b, ectopic expression of hSef-a inhibited fibroblast growth factor-induced cell proliferation. Unlike hSef-b, however, the growth arrest was mediated via a MAPK-independent mechanism, and was accompanied by elevated p38 MAPK phosphorylation and inhibition of protein kinase B/Akt. In addition, hSef-a, but not hSef-b, mediated apoptosis in fibroblast growth factor-stimulated cells. Chemical inhibitor of p38 MAPK abrogated the effect of hSef-a on apoptosis. In epithelial cells, ectopic expression of hSef-a inhibited the activation of MAPK, whereas down-regulation of endogenous hSef-a significantly increased MAPK activation and accelerated growth factor-dependent cell proliferation. These results indicate that hSef-a is a multifunctional negative modulator of RTK signaling and clearly demonstrate that hSef-a can inhibit the activation of MAPK, although in a cell type-specific manner. Moreover, the differences between the activities of hSef-a and hSef-b suggest that hSef isoforms can control signal specificity and subsequent cell fate by utilizing different mechanisms to modulate RTK signaling. Show less