Chronic inflammation decreases arcuate kisspeptin expression in male sheep.

Lipopolysaccharide (LPS) from Gram-negative bacteria induces an immune response and impairs reproduction through suppression of gonadotropin releasing hormone (GnRH), subsequently luteinizing hormone (LH) secretion. While there is evidence that acute inflammation inhibits kisspeptin, little is known about the impact of chronic inflammation on this key reproductive neuropeptide in livestock species. Thus, we sought to examine a central mechanism whereby LPS suppresses LH secretion in sheep. Twenty wethers were randomly assigned to one of five treatment groups: control (CON; n=4), single acute IV LPS dose (SAD; n=4), daily acute IV LPS dose (DAD; n=4), daily increasing IV LPS dose (DID; n=4), and chronic subcutaneous LPS dose (CSD; n=4). On Days 1 and 7, blood samples were collected every 12 minutes for 360 minutes using jugular venipuncture. Following blood collection on Day 7, all animals were euthanized, brain tissue was perfused with 4% paraformaldehyde, and hypothalamic blocks were removed and processed for immunohistochemistry. On Day 1, LH pulse frequency was significantly lower (p=0.02) in SAD (0.25 ± 0.1 pulses/hour), DAD (0.25 ± 0.1 pulses/hour), DID (0.35 ± 0.1 pulses/hour), and CSD (0.40 ± 0.1 pulses/hour) compared to CON (0.70 ±0.1 pulses/hour). On Day 7, only DID animals (0.35 ± 0.1 pulses/hour) had significantly lower (p=0.049) LH pulse frequency compared to controls (0.85 ± 0.1 pulse/hour). Furthermore, only DID animals (33.3 ± 10.9 cells/section/animal) had significantly fewer (p=0.001) kisspeptin-immunopositive cells compared to controls (82.6 ± 13.6 cells/section/animal). Taken together, we suggest that daily increasing doses of LPS is a powerful inhibitor of kisspeptin neurons in young male sheep and a physiologically relevant model to examine the impact of chronic inflammation on the reproductive axis in livestock.

Controlling comonomer distribution in random copolymers by chemical coloring of surface-tethered homopolymers: an insight from discontinuous molecular dynamics simulation.

Postpolymerization chemical modification ("coloring") of homopolymer brushes made of A units using B chemical moieties produces surface-anchored random copolymers (RCPs) A(1-x)B(x), where x is the degree of "coloring". We employ discontinuous molecular dynamics to study the "coloring" process in macromolecular tethers made of various lengths grafted at low and high densities on flat impenetrable surfaces. We demonstrate that the comonomer distribution in the A(1-x)B(x) RCPs depends on the interplay among (1) the length and the grafting density of the A-based homopolymer anchors, (2) the solubility of the parent homopolymer, and (3) the solubility of the B coloring units. Chemical modification of sparsely spaced chains on the surface leads to nearly random comonomer distribution in the A(1-x)B(x) RCPs regardless of the solubility of A and B. In contrast, the distribution of A and B units in A(1-x)B(x) RCPs prepared from homopolymers tethered at high grafting densities depends on the solubility of the parent homopolymer. Chemical modification of well-solvated A homopolymer grafts results in comonomer distributions that resemble those of diblock copolymers, comprising lightly modified blocks near the surface and heavily "colored" blocks at the top of the grafts. The relative lengths of the two blocks can be tuned by varying the solubility of B. Under poor solvent conditions, the distribution of A and B in the A(1-x)B(x) RCP is more complex; it is governed by the conformation of the parent A macromolecular anchors that form collapsed clusters before the coloring reaction.

Interaction between EB1 and p150glued is required for anaphase astral microtubule elongation and stimulation of cytokinesis.

In animal cells, microtubules (MTs) of the mitotic apparatus (MA) communicate with the cell cortex to stimulate cytokinesis; however, the molecular nature of this stimulus remains elusive . A signal for cytokinesis likely involves the MT plus end binding family of proteins, which includes EB1, p150glued, APC, LIS1, and CLIP-170. These proteins modulate MT dynamics and facilitate interactions between growing MTs and their intracellular targets, including kinetochores, organelles, and the cell cortex . The dynein-dynactin complex mediates many of these microtubule capture events . We report that EB1 and p150glued interactions are required for stimulation of cytokinesis in dividing sea urchin eggs. Injected antibodies against EB1 or p150glued suppressed furrow ingression but did not prevent elongation of anaphase astral MTs toward the cortex, suggesting that EB1 and dynactin are both required for communication between the MA and the cortex. Targeted disruption of the interaction between EB1 and p150glued suppressed anaphase astral MT elongation and resulted in a delay of cytokinesis that could not be overcome by manipulation of the asters toward the cortex. We conclude that EB1 and dynactin participate in stimulation of the cleavage furrow, and their interaction promotes elongation of astral MTs at anaphase onset.

Enhanced recovery programmes for lower limb arthroplasty in the UK.

INTRODUCTION: Enhanced recovery programmes (ERPs) reduce patient morbidity and mortality, and provide significant cost savings by reducing length of stay. Currently, no uniform ERP guidelines exist for lower limb arthroplasty in the UK. The aim of this study was to identify variations in ERPs and determine adherence to local policy. METHODS: Hospitals offering elective total knee arthroplasty (TKA) and total hip arthroplasty (THA) (23 and 22 centres respectively) contributed details of their ERPs, and performed an audit (15 patients per centre) to assess compliance. RESULTS: Contrasting content and detail of ERPs was noted across centres. Adherence to ERPs varied significantly (40-100% for TKA, 17-94% for THA). Analysis identified perioperative use of dexamethasone, tranexamic acid and early mobilisation for TKA, and procedures performed in teaching hospitals for THA as being associated with a reduced length of stay. CONCLUSIONS: This study highlights variation in practice and poor compliance with local ERPs. Given the proven benefits of ERPs, evidence-based guidelines in the context of local skillsets should be established to optimise the patient care pathway.

Relationships among temperament, acute and chronic cortisol and testosterone concentrations, and breeding soundness during performance testing of Angus bulls.

The aim of this study was to examine relationships among temperament, endocrinology, and reproductive parameters of bulls enrolled in an 84-day performance test. Angus bulls (n = 60) were housed in six pens grouped by age and weight. Pen scores (PS; 1 = docile to 5 = very aggressive) were assigned on Days -1, 27, 55, and 83 of the performance test. On the following day, blood and hair samples were collected, and body weight (BW) and exit velocity (EV) were recorded. Bulls were split into two categories based on; Day -1 PS (PScalm = PS 1 or 2; PSexcitable = PS 3 or 4) and Day 0 EV (EVcalm = slowest 20 bulls; EVexcitable = fastest 20 bulls). Cortisol and testosterone concentrations in serum and hair did not differ (P > 0.10) between PS or EV temperament categories. Sampling day differences (P < 0.01) occurred for serum testosterone, hair cortisol, and hair testosterone concentration; however, serum cortisol concentration did not differ (P > 0.10) over the sampling days. Serum testosterone concentration increased (P < 0.01) from Day 0 to 28, decreased from Day 28 to 56, but Day 84 did not differ from Day 0, 28, or 56. Hair cortisol concentration was greatest (P < 0.01) on Day 0, decreased from Day 28 to 56 but did not differ from Day 56 to 84. Hair testosterone concentration was greatest (P < 0.01) on Day 0 and remained constant from Day 28 to 84. Bulls categorized as PScalm had a greater (P < 0.01) percentage of normal sperm and secondary defects (P < 0.01) when compared with PSexcitable bulls. However, EVcalm bulls had fewer (P < 0.01) primary defects but more (P < 0.01) secondary defects than EVexcitable bulls. In conclusion, bulls exhibited physiological evidence of acclimation during the test as indicated by a reduction in hair cortisol concentration. In addition, the ability of the bulls to acclimate while residing at the testing center may have contributed to little differences observed during the breeding soundness examination portion of the performance test.

The open conformation of a Pseudomonas lipase.

BACKGROUND: . The interfacial activation of lipases results primarily from conformational changes in the enzymes which expose the active site and provide a hydrophobic surface for interaction with the lipid substrate. Comparison of the crystallization conditions used and the structures observed for a variety of lipases suggests that the enzyme conformation is dependent on solution conditions. Pseudomonas cepacia lipase (PCL) was crystallized in conditions from which the open, active conformation of the enzyme was expected. Its three-dimensional structure was determined independently in three different laboratories and was compared with the previously reported closed conformations of the closely related lipases from Pseudomonas glumae (PGL) and Chromobacterium viscosum (CVL). These structures provide new insights into the function of this commercially important family of lipases. RESULTS: . The three independent structures of PCL superimpose with only small differences in the mainchain conformations. As expected, the observed conformation reveals a catalytic site exposed to the solvent. Superposition of PCL with the PGL and CVL structures indicates that the rearrangement from the closed to the open conformation involves three loops. The largest movement involves a 40 residue stretch, within which a helical segment moves to afford access to the catalytic site. A hydrophobic cleft that is presumed to be the lipid binding site is formed around the active site. CONCLUSIONS: . The interfacial activation of Pseudomonas lipases involves conformational rearrangements of surface loops and appears to conform to models of activation deduced from the structures of fungal and mammalian lipases. Factors controlling the conformational rearrangement are not understood, but a comparison of crystallization conditions and observed conformation suggests that the conformation of the protein is determined by the solution conditions, perhaps by the dielectric constant.

Bulls grazing Kentucky 31 tall fescue exhibit impaired growth, semen quality, and decreased semen freezing potential.

Serum prolactin (PRL) and testosterone concentrations, body weight, body composition, semen quality, and semen freezing potential for bulls grazing the toxic tall fescue (Lolium arundinaceum [Schreb.] Darbysh. = Schedonorous arundinaceum [Schreb.] Dumort.) cultivar Kentucky 31 (E+) compared with a novel endophyte cultivar lacking ergot alkaloids (E-) were evaluated. Angus bulls were allotted to treatment (Day 0) and grazed E+ or E- for 155 days. Treatment-by-day interaction was significant (P < 0.05) for serum PRL concentrations with E+treated bulls exhibiting reduced PRL values compared with E- control bulls, but no differences were observed for serum testosterone concentrations (P > 0.05). Further, bulls on the E+ treatment exhibited decreased total gain, average daily gain, and body weight by Day 140 (P < 0.05) compared with the E- bulls. Rump muscle depth was lower because the treatment in bulls grazing E+ compared with E- (P < 0.05) and intramuscular fat in the E- bulls compared with the E+ group was higher by Day 155 (P < 0.05). Analysis of ejaculates showed significant treatment × day effects for sperm concentration with lower values observed for bulls on the E+ treatment (P < 0.05). The percent normal morphology was reduced in ejaculates from E+ bulls compared with E- bulls (P < 0.05), and the difference was due to an increase in abnormal sperm present in the E+ ejaculates from Day 84 to 140 (P < 0.05). In addition, spermatozoa motility and progressive motility were decreased on thawing in semen samples from E+ bulls compared with E- bulls (P < 0.05).

Lysergic acid diethylamide-induced Fos expression in rat brain: role of serotonin-2A receptors.

Lysergic acid diethylamide (LSD) produces altered mood and hallucinations in humans and binds with high affinity to serotonin-2A (5-HT(2A)) receptors. Although LSD interacts with other receptors, the activation of 5-HT(2A) receptors is thought to mediate the hallucinogenic properties of LSD. The goal of this study was to identify the brain sites activated by LSD and to determine the influence of 5-HT(2A) receptors in this activation. Rats were pretreated with the 5-HT(2A) receptor antagonist MDL 100907 (0.3 mg/kg, i.p.) or vehicle 30 min prior to LSD (500 microg/kg, i.p.) administration and killed 3 h later. Brain tissue was examined for Fos protein expression by immunohistochemistry. LSD administration produced a five- to eight-fold increase in Fos-like immunoreactivity in medial prefrontal cortex, anterior cingulate cortex, and central nucleus of amygdala. However, in dorsal striatum and nucleus accumbens no increase in Fos-like immunoreactivity was observed. Pretreatment with MDL 100907 completely blocked LSD-induced Fos-like immunoreactivity in medial prefrontal cortex and anterior cingulate cortex, but only partially blocked LSD-induced Fos-like immunoreactivity in amygdala. Double-labeled immunohistochemistry revealed that LSD did not induce Fos-like immunoreactivity in cortical cells expressing 5-HT(2A) receptors, suggesting an indirect activation of cortical neurons. These results indicate that the LSD activation of medial prefrontal cortex and anterior cingulate cortex is mediated by 5-HT(2A) receptors, whereas in amygdala 5-HT(2A) receptor activation is a component of the response. These findings support the hypothesis that the medial prefrontal cortex, anterior cingulate cortex, and perhaps the amygdala, are important regions involved in the production of hallucinations.

The hyperplasia-to-carcinoma sequence in the breast. Immunohistochemical-histologic correlations.

Breast cancer is probably the result of a series of genetic events, each with its own histopathologic correlate in the hyperplasia to carcinoma sequence. The expression of breast cancer markers in hyperplasia and tumors are well known, but few studies have investigated their sequential expression among hyperplastic and cancerous lesions within the same breast. Using breast tissue obtained from a single procedure, we correlated the immunohistochemical expression of several breast cancer markers with the histopathologic stage of proliferative breast disease. We selected 14 cases in which various degrees of hyperplasia coexisted with carcinoma. Serial sections were reacted with antibodies to DF3, c-erbB-2, p53 (DO7 and CM1), B72.3, and cyclin D1. We found that within an individual breast, the number of breast cancer markers expressed increased with progression from hyperplasia to atypical hyperplasia to carcinoma. Cytoplasmic DF3 was first expressed at the level of simple hyperplasia, followed by c-erbB-2 in atypical hyperplasia. Overexpression of p53 was confined to carcinomas, and thus appeared to be a late event. B72.3 was expressed in three carcinomas and in one atypical hyperplasia, although the associated carcinoma was negative. Carcinomas that expressed cytoplasmic DF3 and c-erbB-2 were associated with atypical hyperplasias that also expressed cytoplasmic DF3 and c-erbB-2, with one and two exceptions, respectively. No specific cyclin D1 staining pattern was observed.

Crystallographic investigations of subtilisin BPN' mutants engineered for studying thermal stability.

Subtilisin BPN' (BPN) is an industrially important serine protease that has been extensively investigated in many laboratories. In an effort to improve the thermal stability of the enzyme, researchers at Procter & Gamble have used site-directed mutagenesis techniques to produce several variants of BPN in which residues at the surface of the enzyme have been substituted. We initiated crystallographic studies to determine the structural consequences of these amino acid substitutions. In the course of this work we obtained excellent crystals that correspond to the C2 crystal form of native BPN that has been previously reported. Since the structure reported in that work was of only medium resolution, high-resolution X-ray data for this crystal form of native BPN have been collected and the refinement of the structure has been extended using these new data. Isomorphous crystals of two variants, Q19E and Q271E, have also been grown, high-resolution X-ray data have been collected for these crystals, and the experimental results are described. The structures of the native enzyme and the Q271E variant have been refined and are described.

DNA profiling in two Alaskan Native populations using HLA-DQA1, PM, and D1S80 loci.

Two Native Alaskan populations were sampled and DNA profiles were generated for 201 individuals. Ninety two blood samples were collected from the North Slope Borough region of Alaska and the remaining 109 blood samples came from Native Alaskans in the Bethel and Wade Hampton areas. Allele and genotype frequencies were established for the HLA-DQA1, LDLR, GYPA, HBGG, D7S8, Gc, and D1S80 loci. Native Alaskans are slightly less polymorphic than Caucasians at the HLA-DQA1 locus. In contrast, the PM loci appear to be nearly as informative in the Native Alaskan populations as in Caucasians for identity testing. The data clearly demonstrate that all the loci tested are highly informative for the Alaskan populations and fall well within Hardy-Weinberg expectations. There is little evidence for departure from expectation of independence of alleles across loci. The data demonstrate that estimates of multiple locus profile frequencies can be obtained from Native Alaskan populations using the product rule under the assumption of independence of loci. In addition, Native Alaskan databases were more similar to each other and to other Native American databases than they were to U.S. Caucasians and African Americans.

The ability of professional programs in occupational therapy to accommodate the older student.

Research data suggest that 24% of the 25- to 34-year-old age group are college graduates who are prime candidates for returning to the university campus. As a professional field in which the enrollment of traditional-age students might decline, occupational therapy may need to find ways to attract older students. Thus, there is a need to examine whether occupational therapy curricula are designed to accommodate older students.

Accountability and competence: occupational therapy practitioner perceptions.

OBJECTIVE: Occupational therapy practitioners must meet ever-increasing accountability demands in all service delivery environments. Accountability is made possible through the ongoing development of continued competence throughout a practitioner's career. Behaviors that demonstrate accountability and reflect competence include commitment, leadership, and professional knowledge. This article discusses issues related to accountability and competence, presents findings from focus group discussions with occupational therapy practitioners regarding professional competence, and identifies actions that will bring about greater understanding of this topic. METHOD: Thirty-nine randomly selected occupational therapy practitioners attended one of two focus groups. Participants responded to a structured discussion guide, including questions addressing the definition, process for sustaining, and outcomes of continued competence. RESULTS: Several themes emerged from these discussions. Views about what constitutes and contributes to continued competence in occupational therapy were diverse, and perceptions of occupational therapy "practice" were broad. Participants believed that the "outcomes" of a practitioner's continued competence were best defined as autonomy in executing the occupational therapy process. CONCLUSIONS: Findings offer potential language to articulate competence in occupational therapy and facilitate a discipline-wide conversation. The findings likewise challenge practitioners to assume new professional behaviors that require both personal and interpersonal skills. Such behaviors are critical to demonstrating accountability and competence.

Exploring sensory integrative dysfunction in process schizophrenia.

During a 6-week period, the effects of sensory integrative activities on a group of seven chronic nonparanoid schizophrenic adults were compared to the effects of sedentary activities in a control group of seven similar subjects. The effects of each therapeutic approach were evaluated by measuring the patients' performance in several areas using the Nurses Observation Scale of Inpatient Evaluation-30 (NOSIE-30), The Object Manipulation Speed Test, a gait analysis, and grip strength. The results indicated general improvement in the experimental group. Behaviors measured by the NOSIE-30 showed the most significant improvements. The control group showed isolated improvements in grooming (measured by the NOSIE-30) and in right-hand use (measured by The Object Manipulation Speed Test). These findings suggest that 6 weeks of sensory integrative activities can improve the overall functioning of chronic nonparanoid schizophrenic patients, facilitate their adaptive responses, and enable them to participate more fully in other areas of therapeutic intervention.

Simulation study of the structure and phase behavior of ceramide bilayers and the role of lipid head group chemistry.

Ceramides are known to be a key component of the stratum corneum, the outermost protective layer of the skin that controls barrier function. In this work, molecular dynamics simulations are used to examine the behavior of ceramide bilayers, focusing on non-hydroxy sphingosine (NS) and non-hydroxy phytosphingosine (NP) ceramides. Here, we propose a modified version of the CHARMM force field for ceramide simulation, which is directly compared to the more commonly used GROMOS-based force field of Berger (Biophys. J. 1997, 72); while both force fields are shown to closely match experiment from a structural standpoint at the physiological temperature of skin, the modified CHARMM force field is better able to capture the thermotropic phase transitions observed in experiment. The role of ceramide chemistry and its impact on structural ordering is examined by comparing ceramide NS to NP, using the validated CHARMM-based force field. These simulations demonstrate that changing from ceramide NS to NP results in changes to the orientation of the OH groups in the lipid headgroups. The arrangement of OH groups perpendicular to the bilayer normal for ceramide NP, verse parallel for NS, results in the formation of a distinct hydrogen bonding network, that is ultimately responsible for shifting the gel-to-liquid phase transition to higher temperature, in direct agreement with experiment.