Low-coverage vaccination strategies for the conservation of endangered species

The conventional objective of vaccination programmes is to eliminate infection by reducing the reproduction number of an infectious agent to less than one, which generally requires vaccination of the majority of individuals. In populations of endangered wildlife, the intervention required to deliver such coverage can be undesirable and impractical; however, endangered populations are increasingly threatened by outbreaks of infectious disease for which effective vaccines exist. As an alternative, wildlife epidemiologists could adopt a vaccination strategy that protects a population from the consequences of only the largest outbreaks of disease. Here we provide a successful example of this strategy in the Ethiopian wolf, the world's rarest canid, which persists in small subpopulations threatened by repeated outbreaks of rabies introduced by domestic dogs. On the basis of data from past outbreaks, we propose an approach that controls the spread of disease through habitat corridors between subpopulations and that requires only low vaccination coverage. This approach reduces the extent of rabies outbreaks and should significantly enhance the long-term persistence of the population. Our study shows that vaccination used to enhance metapopulation persistence through elimination of the largest outbreaks of disease requires lower coverage than the conventional objective of reducing the reproduction number of an infectious agent to less than one.

Production of Haemophilus influenzae b meningitis in infant rats by intraperitoneal inoculation

Sprague-Dawley rats have a marked age-related susceptibility to Haemophilus influenzae type b that does not correlate with serum bactericidal activity. Eighty percent of 5-day-old animals that survive to 48 h after an intraperitoneal inoculation of a mean lethal dose of bacteria have histologically documented meningitis. Animals surviving the inoculations as infants manifest cerebral dysfunction as adults. This model should facilitate experimental study of bacterial meningitis.

Continuous lumbar plexus block for postoperative pain control after total hip arthroplasty. A randomized controlled trial

BACKGROUND

Continuous femoral or lumbar plexus blocks have been demonstrated to provide effective postoperative analgesia of the lower extremity following total joint arthroplasty. The purpose of this study was to compare these two techniques when used with intravenous patient-controlled analgesia and the use of patient-controlled analgesia alone for postoperative pain management following unilateral primary hip arthroplasty.

METHODS

Two hundred and twenty-five patients undergoing unilateral total hip arthroplasty for a diagnosis of osteoarthritis were randomly allocated into one of three postoperative treatment groups: continuous lumbar plexus block with patient-controlled analgesia, continuous femoral block with patient-controlled analgesia, and patient-controlled analgesia alone. Scores on a visual analog pain scale administered during physiotherapy twenty-four hours postoperatively were used as the primary outcome measured. Secondary outcomes included scores on a visual analog pain scale at rest, hydromorphone consumption, opioid-related side effects, complications, sensory and motor blockade, and patient satisfaction.

RESULTS

Continuous lumbar plexus block significantly reduced pain scores during physiotherapy on postoperative day 1 (p < 0.0001) and day 2 (p < 0.0001) compared with either continuous femoral block or patient-controlled analgesia alone. There were no significant differences for pain at rest between the two regional analgesic techniques. Both regional anesthesia techniques significantly reduced total hydromorphone consumption (p < 0.05) and delirium (disorientation to time and/or place) compared with patient-controlled analgesia alone (p < 0.023). In addition, the use of continuous lumbar plexus block was associated with fewer patients with opioid-related side effects (p < 0.05), greater distances walked (p < 0.05), and enhanced patient satisfaction (p < 0.05) compared with the use of a continuous femoral nerve block with patient-controlled analgesia or with patient-controlled analgesia alone.

CONCLUSIONS

Continuous lumbar plexus and femoral blocks significantly reduce the need for opioids and decrease related side effects. Continuous lumbar plexus block is a more effective analgesic modality than is a continuous femoral block or patient-controlled intravenous administration of hydromorphone alone during physical therapy following primary unilateral total hip arthroplasty.

The glucocorticoid receptor: cause of or cure for obesity?

Glucocorticoid hormones (GCs) are important regulators of lipid metabolism, promoting lipolysis with acute treatment but lipogenesis with chronic exposure. Conventional wisdom posits that these disparate outcomes are mediated by the classical glucocorticoid receptor GRα. There is insufficient knowledge of the GC receptors (GRα and GRβ) in metabolic conditions such as obesity and diabetes. We present acute models of GC exposure that induce lipolysis, such as exercise, as well as chronic-excess models that cause obesity and lipid accumulation in the liver, such as hepatic steatosis. Alternative mechanisms are then proposed for the lipogenic actions of GCs, including induction of GC resistance by the GRβ isoform, and promotion of lipogenesis by GC activation of the mineralocorticoid receptor (MR). Finally, the potential involvement of chaperone proteins in the regulation of adipogenesis is considered. This reevaluation may prove useful to future studies on the steroidal basis of adipogenesis and obesity.

Mitotic Disassembly of Nuclear Pore Complexes Involves CDK1- and PLK1-Mediated Phosphorylation of Key Interconnecting Nucleoporins

During interphase, the nuclear envelope (NE) serves as a selective barrier between cytosol and nucleoplasm. When vertebrate cells enter mitosis, the NE is dismantled in the process of nuclear envelope breakdown (NEBD). Disassembly of nuclear pore complexes (NPCs) is a key aspect of NEBD, required for NE permeabilization and formation of a cytoplasmic mitotic spindle. Here, we show that both CDK1 and polo-like kinase 1 (PLK1) support mitotic NPC disintegration by hyperphosphorylation of Nup98, the gatekeeper nucleoporin, and Nup53, a central nucleoporin linking the inner NPC scaffold to the pore membrane. Multisite phosphorylation of Nup53 critically contributes to its liberation from its partner nucleoporins, including the pore membrane protein NDC1. Initial steps of NPC disassembly in semi-permeabilized cells can be reconstituted by a cocktail of mitotic kinases including cyclinB-CDK1, NIMA, and PLK1, suggesting that the unzipping of nucleoporin interactions by protein phosphorylation is an important principle underlying mitotic NE permeabilization.

Delayed puberty but normal fertility in mice with selective deletion of insulin receptors from Kiss1 cells

Pubertal onset only occurs in a favorable, anabolic hormonal environment. The neuropeptide kisspeptin, encoded by the Kiss1 gene, modifies GnRH neuronal activity to initiate puberty and maintain fertility, but the factors that regulate Kiss1 neurons and permit pubertal maturation remain to be clarified. The anabolic factor insulin may signal nutritional status to these neurons. To determine whether insulin sensing plays an important role in Kiss1 neuron function, we generated mice lacking insulin receptors in Kiss1 neurons (IR(ΔKiss) mice). IR(ΔKiss) females showed a delay in vaginal opening and in first estrus, whereas IR(ΔKiss) males also exhibited late sexual maturation. Correspondingly, LH levels in IR(ΔKiss) mice were reduced in early puberty in both sexes. Adult reproductive capacity, body weight, fat composition, food intake, and glucose regulation were comparable between the 2 groups. These data suggest that impaired insulin sensing by Kiss1 neurons delays the initiation of puberty but does not affect adult fertility. These studies provide insight into the mechanisms regulating pubertal timing in anabolic states.

Irinotecan combined with gemcitabine, 5-fluorouracil, leucovorin, and cisplatin (G-FLIP) is an effective and noncrossresistant treatment for chemotherapy refractory metastatic pancreatic cancer

BACKGROUND

Single agents have only modest activity as treatment for metastatic pancreatic cancer with response rates of less than 10% and median survivals of less than 6 months. Evaluations of single-agent gemcitabine and rubitecan as second-line treatment for relapsed pancreatic cancer have reported good patient tolerability and median survivals of 3.85 months and 4.7 months, respectively. Regimens incorporating two drugs have demonstrated encouraging activity and clinical impact compared with single-agent therapy. G-FLIP is a regimen designed to incorporate four active single agents into a tolerable and active combination. This analysis is a retrospective evaluation of the efficacy and safety of the G-FLIP regimen as second-line chemotherapy in a series of consecutively treated patients with metastatic pancreatic cancer.

METHODS

G-FLIP was administered over 48 hours and repeated every 2 weeks. Day 1 treatment consisted of sequentially administered gemcitabine 500 mg/m(2), irinotecan 80 mg/m(2), leucovorin 300 mg, 5-fluorouracil (5-FU) 400 mg/m(2) bolus followed by infusional 5-FU 600 mg/m(2) over 8 hours. Day 2 treatment consisted of leucovorin 300 mg and 5-FU 400 mg/m(2) bolus, followed by cisplatin 50 to 75 mg/m(2), and then infusional 5-FU 600 mg/m(2) over 8 hours.

RESULTS

Thirty-four patients with histologically confirmed metastatic pancreatic cancer were consecutively treated. The median patient age was 64.5 years (range 41-82 years) and all patients had objective disease progression on prior therapy: 32 patients had disease progression with gemcitabine and 31 had disease progression with a gemcitabine/5-fluorouracil/cisplatin combination. Grade 3-4 hematological toxicities included anemia (23%), thrombocytopenia (53%), and neutropenia (38%). There were no grade 3-4 neutropenic fevers, treatment-related mortalities, or withdrawals. Nonhematological grade 3-4 toxicities were rare: nausea/vomiting (3%), neurotoxicity (3%), nephrotoxicity (6%), and diarrhea (3%). Based on RECIST criteria a partial response (PR) was attained in eight patients (24%) and seven patients had stable disease (SD). Seven and six patients who attained a PR or SD, respectively, had disease progression with prior gemcitabine-based therapy. The median time to disease progression for all 34 patients was 3.9 months and 5.9 months for the eight patients who attained a PR. Median overall survival for all 34 patients was 10.3 months.

CONCLUSION

Adding a single new drug such as irinotecan to the same first-line chemotherapy combination upon disease progression may be an important alternative to switching to different drug classes for treatment of relapsed/resistant cancer. The promising clinical outcomes and moderate toxicity associated with G-FLIP in this heavily pretreated group warrant development of this novel regimen including tests as first-line therapy in patients with diseases likely to be responsive to the drugs contained in this combination.

Aggressive natural killer cell lymphoma/leukemia. A recently recognized clinicopathologic entity

We report a comprehensive study of a case of aggressive natural killer cell lymphoma/leukemia, which is characterized by young male predominance, rapidly progressive clinical course, and presence of lymphadenopathy, hepatosplenomegaly, and bone marrow involvement. The leukemic phase is frequently preceded by pancytopenia. The diagnostic clues are the detection of cytoplasmic granules in tumor cells on Wright-Giemsa-stained tissue imprints or smears and a selective loss of T-cell antigens. Immunophenotyping is decisive in making the final diagnosis by showing positive natural killer cell markers (CD16, CD56, and/or CD57), CD2, CD11c, and Ia, but negative CD3, T-cell receptor heterodimers, terminal deoxynucleotidyl transferase, and B-cell markers. Genotyping always shows germline configuration in both immunoglobulin and T-cell receptor genes. The unique feature in this case is its presentation as a testicular lymphoma, which has not been previously reported. Polymerase chain reaction was performed in this case but failed to detect human T-cell leukemia virus type I/II provirus. It is important to recognize this new entity as it is a highly aggressive disease with a rapidly progressive clinical course and fails to respond to any chemotherapeutic regimen available.

Glucocorticoid Receptor β Induces Hepatic Steatosis by Augmenting Inflammation and Inhibition of the Peroxisome Proliferator-activated Receptor (PPAR) α

Glucocorticoids (GCs) regulate energy supply in response to stress by increasing hepatic gluconeogenesis during fasting. Long-term GC treatment induces hepatic steatosis and weight gain. GC signaling is coordinated via the GC receptor (GR) GRα, as the GRβ isoform lacks a ligand-binding domain. The roles of the GR isoforms in the regulation of lipid accumulation is unknown. The purpose of this study was to determine whether GRβ inhibits the actions of GCs in the liver, or enhances hepatic lipid accumulation. We show that GRβ expression is increased in adipose and liver tissues in obese high-fat fed mice. Adenovirus-mediated delivery of hepatic GRβ overexpression (GRβ-Ad) resulted in suppression of gluconeogenic genes and hyperglycemia in mice on a regular diet. Furthermore, GRβ-Ad mice had increased hepatic lipid accumulation and serum triglyceride levels possibly due to the activation of NF-κB signaling and increased tumor necrosis factor α (TNFα) and inducible nitric-oxide synthase expression, indicative of enhanced M1 macrophages and the development of steatosis. Consequently, GRβ-Ad mice had increased glycogen synthase kinase 3β (GSK3β) activity and reduced hepatic PPARα and fibroblast growth factor 21 (FGF21) expression and lower serum FGF21 levels, which are two proteins known to increase during fasting to enhance the burning of fat by activating the β-oxidation pathway. In conclusion, GRβ antagonizes the GC-induced signaling during fasting via GRα and the PPARα-FGF21 axis that reduces fat burning. Furthermore, hepatic GRβ increases inflammation, which leads to hepatic lipid accumulation.

Central insulin and leptin-mediated autonomic control of glucose homeostasis

Largely as a result of rising obesity rates, the incidence of type 2 diabetes is escalating rapidly. Type 2 diabetes results from multi-organ dysfunctional glucose metabolism. Recent publications have highlighted hypothalamic insulin- and adipokine-sensing as a major determinant of peripheral glucose and insulin responsiveness. The preponderance of evidence indicates that the brain is the master regulator of glucose homeostasis, and that hypothalamic insulin and leptin signaling in particular play a crucial role in the development of insulin resistance. This review discusses the neuronal crosstalk between the hypothalamus, autonomic nervous system, and tissues associated with the pathogenesis of type 2 diabetes, and how hypothalamic insulin and leptin signaling are integral to maintaining normal glucose homeostasis.

Association of Opioids and Sedatives with Increased Risk of In-Hospital Cardiopulmonary Arrest from an Administrative Database

Background

While opioid use confers a known risk for respiratory depression, the incremental risk of in-hospital cardiopulmonary arrest, respiratory arrest, or cardiopulmonary resuscitation (CPRA) has not been studied. Our aim was to investigate the prevalence, outcomes, and risk profile of in-hospital CPRA for patients receiving opioids and medications with central nervous system sedating side effects (sedatives).

Methods

A retrospective analysis of adult inpatient discharges from 2008–2012 reported in the Premier Database. Patients were grouped into four mutually exclusive categories: (1) opioids and sedatives, (2) opioids only, (3) sedatives only, and (4) neither opioids nor sedatives.

Results

Among 21,276,691 inpatient discharges, 53% received opioids with or without sedatives. A total of 96,554 patients suffered CPRA (0.92 per 1000 hospital bed-days). Patients who received opioids and sedatives had an adjusted odds ratio for CPRA of 3.47 (95% CI: 3.40–3.54; p<0.0001) compared with patients not receiving opioids or sedatives. Opioids alone and sedatives alone were associated with a 1.81-fold and a 1.82-fold (p<0.0001 for both) increase in the odds of CPRA, respectively. In opioid patients, locations of CPRA were intensive care (54%), general care floor (25%), and stepdown units (15%). Only 42% of patients survived CPRA and only 22% were discharged home. Opioid patients with CPRA had mean increased hospital lengths of stay of 7.57 days and mean increased total hospital costs of $27,569.

Conclusions

Opioids and sedatives are independent and additive risk factors for in-hospital CPRA. The impact of opioid sparing analgesia, reduced sedative use, and better monitoring on CPRA incidence deserves further study.

Glucocorticoid receptor β stimulates Akt1 growth pathway by attenuation of PTEN

Glucocorticoids (GCs) are known inhibitors of proliferation and are commonly prescribed to cancer patients to inhibit tumor growth and induce apoptosis via the glucocorticoid receptor (GR). Because of alternative splicing, the GR exists as two isoforms, GRα and GRβ. The growth inhibitory actions of GCs are mediated via GRα, a hormone-induced transcription factor. The GRβ isoform, however, lacks helix 12 of the ligand-binding domain and cannot bind GCs. While we have previously shown that GRβ mRNA is responsive to insulin, the role of GRβ in insulin signaling and growth pathways is unknown. In the present study, we show that GRβ suppresses PTEN expression, leading to enhanced insulin-stimulated growth. These characteristics were independent of the inhibitory qualities that have been reported for GRβ on GRα. Additionally, we found that GRβ increased phosphorylation of Akt basally, which was further amplified following insulin treatment. In particular, GRβ specifically targets Akt1 in growth pathways. Our results demonstrate that the GRβ/Akt1 axis is a major player in insulin-stimulated growth.

Association of an RNA kissing complex analyzed using 2-aminopurine fluorescence

The fluorescent probe, 2-aminopurine-2'-O-methyl riboside (2-AP) has been selectively incorporated at adenosine positions in stem-loops (so called R1inv and R2inv), derived from the ColE1 plasmid encoded RNA I and RNA II transcripts, that interact to form stable loop-loop kissing complexes and bind the RNA one modulator (Rom) protein, such that fluorescence-detected stopped-flow and equilibrium methods could be used to study the detailed mechanism of this RNA-RNA interaction. Formation of loop-loop kissing complexes between R1inv and R2inv hairpins, substituted with 2-AP at positions in the complementary loops, results in a 5-10-fold fluorescence emission decrease (F(max) = 370 nm), which provides a sensitive measure for the binding reaction. The 2-AP substituted complexes are found to have equilibrium binding properties (average K(D) = 2.6 +/- 1.7 nM) and affinity for Rom (average K(D) = 60 +/- 24 nM) that are similar to complexes formed with equivalent unlabeled hairpins. Using stopped-flow experiments, it was found that the 2-AP probes experienced at least three different microenvironments during association of the RNA complex, thus suggesting a kinetic intermediate in the kissing pathway. In contrast, dissociation of the complex was found to fit a single exponential decay (average k(off) = 8.9 x 10(-5) s(-1)). Consistent with these observations, a two-step mechanism for RNA loop-loop complex association is proposed in which the complementary loops of R1inv and R2inv first base pair to form the loop-loop helix (average k(1) = 0.13 microM(-1)s(-1)) in the initial encounter reaction, and subsequently isomerize to the final tertiary fold in a second slower step (average k(2) = 0.09 s(-1)), where the helical stacking around the junctions is optimized.

Beta2-integrins contribute to skeletal muscle hypertrophy in mice

We tested the contribution of beta(2)-integrins, which are important for normal function of neutrophils and macrophages, to skeletal muscle hypertrophy after mechanical loading. Using the synergist ablation model of hypertrophy and mice deficient in the common beta-subunit of beta(2)-integrins (CD18(-/-)), we found that overloaded muscles of wild-type mice had greater myofiber size, dry muscle mass, and total protein content compared with CD18(-/-) mice. The hypertrophy in wild-type mice was preceded by elevations in neutrophils, macrophages, satellite cell/myoblast proliferation (5'-bromo-2'-deoxyuridine- and desmin-positive cells), markers of muscle differentiation (MyoD1 and myogenin gene expression and formation and size of regenerating myofibers), signaling for protein synthesis [phosphorylation of Akt and 70-kDa ribosomal protein S6 kinase (p70S6k)], and reduced signaling for protein degradation (decreased gene expression of muscle atrophy F box/atrogin-1). The deficiency in beta(2)-integrins, however, altered the accumulation profile of neutrophils and macrophages, disrupted the temporal profile of satellite cell/myoblast proliferation, reduced the markers of muscle differentiation, and impaired the p70S6k signaling, all of which could serve as mechanisms for the impaired hypertrophy in overloaded CD18(-/-) mice. In conclusion, our findings indicate that beta(2)-integrins contribute to the hypertrophic response to muscle overload by temporally regulating satellite cells/myoblast proliferation and by enhancing muscle differentiation and p70S6k signaling.

Infection caused by vancomycin-resistant Streptococcus sanguis II

A patient with bacteremia caused by vancomycin-resistant Streptococcus sanguis II is presented. This rare occurrence suggests that vancomycin may not be a completely reliable antibiotic in the treatment of infections due to viridans species of the genus Streptococcus. Gram-positive isolates from blood and otherwise sterile body fluids should be tested for susceptibility to vancomycin.

High Fat Rodent Models of Type 2 Diabetes: From Rodent to Human

Poor dietary habits contribute to increased incidences of obesity and related co-morbidities, such as type 2 diabetes (T2D). The biological, genetic, and pathological implications of T2D, are commonly investigated using animal models induced by a dietary intervention. In spite of significant research contributions, animal models have limitations regarding the translation to human pathology, which leads to questioning their clinical relevance. Important considerations include diet-specific effects on whole organism energy balance and glucose and insulin homeostasis, as well as tissue-specific changes in insulin and glucose tolerance. This review will examine the T2D-like phenotype in rodents resulting from common diet-induced models and their relevance to the human disease state. Emphasis will be placed on the disparity in percentages and type of dietary fat, the duration of intervention, and whole organism and tissue-specific changes in rodents. An evaluation of these models will help to identify a diet-induced rodent model with the greatest clinical relevance to the human T2D pathology. We propose that a 45% high-fat diet composed of approximately one-third saturated fats and two-thirds unsaturated fats may provide a diet composition that aligns closely to average Western diet macronutrient composition, and induces metabolic alterations mirrored by clinical populations.

Periarticular regional analgesia in total knee arthroplasty: a review of the neuroanatomy and injection technique

Postoperative pain control after total knee arthroplasty may be insufficient, resulting in insomnia, antalgic ambulation, and difficulty with rehabilitation. Current strategies, including the use of femoral nerve catheters, may control pain but have been associated with falls, motor blockade, and quadriceps inhibition. Periarticular infiltration using the appropriate technique and knowledge of intraarticular knee anatomy may increase pain control and maximize rehabilitation.

Identification of heterozygote carriers of congenital adrenal hyperplasia by radioimmunoassay of serum 17-OH progesterone

The response to administered adrenocorticotropin (ACTH, Cortrosyn) of 26 heterozygotes (parents of children with adrenal 21-hydroxylase deficiency) and of 14 controls are compared. The mean plasma levels of 4-pregnene-3, 20-dione-17, 21-diol (17-OH progesterone) were significantly greater in the heterozygotes 60 minutes (p less than 0.02) and 90 minutes (p less than 0.05) after stimulation with Cortrosyn than in controls. There is, however, considerable overlap. The results would indicate a partial enzyme deficiency in the parents of diseased subjects. There was no significant difference in the response of plasma cortisol.

Use of cisplatin for elderly patients

The ageing of the population has resulted in a greater emphasis on cancer treatment effects in elderly patients. This population has often had arbitrary dose modification of chemotherapy owing to fear of excessive side-effects. A review was undertaken to evaluate cisplatin toxicity in patients of 70 years of age or older. Thirty-four patients were evaluated. Their mean age was 72.8 years and 85.3% were women. Fourteen of 34 (41%) patients completed the planned therapy. Treatment was terminated because of disease progression (35%), renal toxicity (9%) and non-renal toxicity (15%). Our conclusion is that cisplatin can safely be administered to elderly patients. Arbitrary dose modification or elimination of cisplatin from a treatment programme on the grounds of patient age alone is not justified.

Sensorimotor cortical influences on cuneate nucleus rhythmic activity in the anesthetized cat

This work aimed to study whether the sensorimotor cerebral cortex spreads down its rhythmic patterns of activity to the dorsal column nuclei. Extracellular and intracellular recordings were obtained from the cuneate nucleus of chloralose-anesthetized cats. From a total of 140 neurons tested (106 cuneolemniscal), 72 showed spontaneous rhythmic activity within the slow (< 1 Hz), delta (1-4 Hz), spindle (5-15 Hz) and higher frequencies, with seven cells having the delta rhythm coupled to slow oscillations. The spindle activity recorded in the cuneate was tightly coupled to the thalamo-cortico-thalamic spindle rhythmicity. Bilateral or contralateral removal of the frontoparietal cortex abolished the cuneate slow and spindle oscillations. Oscillatory paroxysmal activity generated by fast electrical stimulation (50-100 Hz/1-2 s) of the sensorimotor cortex induced burst firing synchronized with the paroxysmal cortical "spike" on all the non-lemniscal neurons, and inhibitory responses also coincident with the cortical paroxysmal "spike" in the majority (71%) of the cuneolemniscal cells. The remaining lemniscal-projecting neurons showed bursting activity (11%) or sequences of excitation-inhibition (18%) also time-locked to the cortical paroxysmal "spike". Additionally, the cerebral cortex induced coherent oscillatory activity between thalamic ventroposterolateral and cuneate neurons. Electrolytic lesion of the pyramidal tract abolished the cortically induced effects on the contralateral cuneate nucleus, as well as on the ipsilateral medial lemniscus. The results demonstrate that the sensorimotor cortex imposes its rhythmic patterns on the cuneate nucleus through the pyramidal tract, and that the corticocuneate network can generate normal and abnormal patterns of synchronized activity, such as delta waves, spindles and spike-and-wave complexes. The cuneate neurons, however, are able to generate oscillatory activity above 1 Hz in the absence of cortical input, which implies that the cerebral cortex probably imposes its rhythmicity on the cuneate by matching the intrinsic preferred oscillatory frequency of cuneate neurons.

Diagnosis of nosocomial pneumonia in intubated, intensive care unit patients

The clinical distinction between bacterial colonization of the tracheobronchial tree and nosocomial pneumonia is difficult, especially in intubated patients. We studied 51 intubated, intensive care unit patients prospectively by serial examinations of tracheal aspirates for elastin fibers, graded Gram's stains, and quantitative bacterial cultures in conjunction with clinical and radiologic observations in an attempt to develop criteria for the early detection of pulmonary infection. Patients with infection had new or progressive pulmonary infiltrates plus 1 of the following: positive blood culture results, radiographic evidence of cavitation, or histologic evidence of pneumonia, or 2 or more of the following: new fever, new leukocytosis, or grossly purulent tracheal aspirates. Twenty-one patients developed infection, 22 remained colonized, and 8 had an uncertain status. Infiltrates developed in 34 patients (21 infected, 8 colonized, 5 uncertain status). Gram-negative bacilli were most commonly isolated and were more frequent in infected patients (81 versus 47%, p less than 0.05); Pseudomonas aeruginosa and Serratia marcescens were most often associated with infection. No differences were observed between infected and colonized patients in demographic features, smoking history, underlying disease, previous antibiotic therapy, days in hospital before intubation, preexisting pneumonia upon intubation, or highest temperature or leukocyte count during course. By univariate analysis, infected patients had a longer duration of intubation (p less than 0.05), higher Gram's stain grading for neutrophils (p less than 0.05) or bacteria (p less than 0.005), higher bacterial colony counts (p less than 0.05), and more frequent detection of elastin fibers in tracheal aspirates (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipocyte dysfunction in a mouse model of polycystic ovary syndrome (PCOS): evidence of adipocyte hypertrophy and tissue-specific inflammation

Clinical research shows an association between polycystic ovary syndrome (PCOS) and chronic inflammation, a pathological state thought to contribute to insulin resistance. The underlying pathways, however, have not been defined. The purpose of this study was to characterize the inflammatory state of a novel mouse model of PCOS. Female mice lacking leptin and insulin receptors in pro-opiomelanocortin neurons (IR/LepR(POMC) mice) and littermate controls were evaluated for estrous cyclicity, ovarian and adipose tissue morphology, and body composition by QMR and CT scan. Tissue-specific macrophage infiltration and cytokine mRNA expression were measured, as well as circulating cytokine levels. Finally, glucose regulation during pregnancy was evaluated as a measure of risk for diabetes development. Forty-five percent of IR/LepR(POMC) mice showed reduced or absent ovulation. IR/LepR(POMC) mice also had increased fat mass and adipocyte hypertrophy. These traits accompanied elevations in macrophage accumulation and inflammatory cytokine production in perigonadal adipose tissue, liver, and ovary. These mice also exhibited gestational hyperglycemia as predicted. This report is the first to show the presence of inflammation in IR/LepR(POMC) mice, which develop a PCOS-like phenotype. Thus, IR/LepR(POMC) mice may serve as a new mouse model to clarify the involvement of adipose and liver tissue in the pathogenesis and etiology of PCOS, allowing more targeted research on the development of PCOS and potential therapeutic interventions.

Overexpression of Glucocorticoid Receptor β Enhances Myogenesis and Reduces Catabolic Gene Expression

Unlike the glucocorticoid receptor α (GRα), GR β (GRβ) has a truncated ligand-binding domain that prevents glucocorticoid binding, implicating GRα as the mediator of glucocorticoid-induced skeletal muscle loss. Because GRβ causes glucocorticoid resistance, targeting GRβ may be beneficial in impairing muscle loss as a result of GRα activity. The purpose of this study was to determine how the overexpression of GRβ affects myotube formation and dexamethasone (Dex) responsiveness. We measured GR isoform expression in C₂C12 muscle cells in response to Dex and insulin, and through four days of myotube formation. Next, lentiviral-mediated overexpression of GRβ in C₂C12 was performed, and these cells were characterized for cell fusion and myotube formation, as well as sensitivity to Dex via the expression of ubiquitin ligases. GRβ overexpression increased mRNA levels of muscle regulatory factors and enhanced proliferation in myoblasts. GRβ overexpressing myotubes had an increased fusion index. Myotubes overexpressing GRβ had lower forkhead box O3 (Foxo3a) mRNA levels and a blunted muscle atrophy F-box/Atrogen-1 (MAFbx) and muscle ring finger 1 (MuRF1) response to Dex. We showed that GRβ may serve as a pharmacological target for skeletal muscle growth and protection from glucocorticoid-induced catabolic signaling. Increasing GRβ levels in skeletal muscle may cause a state of glucocorticoid resistance, stabilizing muscle mass during exposure to high doses of glucocorticoids.