Dendritic development and preferential growth into synaptogenic fields: a quantitative study of Golgi-impregnated spinal motor neurons

Branching patterns of dendrites may be modulated by the way in which dendritic growth cone filopodia come into initial synaptic relationships with afferent axons. This synaptotropic hypothesis of dendritic branching predicts that dendritic growth will be directed preferentially into regions containing numerous prospective presynaptic elements. The developing mouse spinal cord provides a natural experiment to test this prediction, because synapses are found exclusively within the marginal zones bordering the motor columns during the early (E11-14) period of synaptogenesis. During this time, therefore, most motor dendritic growth would be expected to be directed laterally or ventrally into the marginal zones, whereas internally directed growth should become more prevalent later, when synaptogenesis begins to take place within the intermediate zone, i.e., the motor columns proper. A computer-assisted three dimensional reconstruction system has been used to test these expectations in Golgi preparations of developing mouse (C57BL/6J) spinal cords ranging in age from E13 through P1. Mean dendritic lengths and branch densities are significantly greater for marginal zone dendrites than for intermediate zone dendrites at early ages (E13-14), but there are no significant differences in these measures at later stages of development (P0,1). These findings are interpreted as meaning that motor dendritic growth is initially biased into the marginal zone by synaptogenic afferents and that this preferential distribution is progressively lost as synapses develop within the intermediate zone to attract or to stabilize internally directed dendritic growth. Thus the findings of this study are consistent with predictions of the synaptotropic hypothesis of dendritic branching.     

Differentiation between rat brain and mouse vas deferens delta opioid receptors

Certain enkephalin analogues, including those which contain the conformationally restricted amino acid E-(2R,3S)-cyclopropylphenylalanine [2R,3S)-delta E Phe), have been shown to have high affinity for brain delta opioid receptors but are much less active in mouse vas deferens bioassays. To investigate whether there are differences between delta opioid receptors in brain and mouse was deferens, the ability of a selective delta opioid compound, [D-Pen2,pCl-Phe4,D-Pen5]enkephalin (pCl-DPDPE), and [D-Ala2,(2R,3S)-delta E Phe4,Leu5]enkephalin methyl ester (CP-OMe), to inhibit [3H]pCl-DPDPE binding in both rat brain and mouse vas deferens were measured. pCl-DPDPE recognized brain and mouse vas deferens binding sites with equal affinity, however, CP-OMe showed 33 fold lower affinity in mouse vas deferens compared to brain. This suggests that mouse vas deferens delta opioid receptors may be distinct from brain delta opioid receptors.     

Obesity in Diabetic Patients Undergoing Coronary Artery Bypass Graft Surgery Is Associated with Increased Postoperative Morbidity

Background: Despite the fact that obesity is a known risk factor for cardiovascular disease, many studies have failed to demonstrate that obesity is independently associated with an increased risk of cardiovascular morbidity and mortality in nondiabetic patients undergoing coronary artery bypass graft surgery. The authors investigated the influence of obesity on adverse postoperative outcomes in diabetic and nondiabetic patients after primary coronary artery bypass surgery.

Methods: A retrospective cohort study of patients undergoing primary coronary artery bypass surgery (n = 9,862) between January 1995 and December 2004 at the Texas Heart Institute was performed. Diabetic (n = 3,374) and nondiabetic patients (n = 6,488) were classified into five groups, according to their body mass index: normal weight (n = 2,148), overweight (n = 4,257), mild obesity (n = 2,298), moderate obesity (n = 785), or morbid obesity (n = 338). Multivariate, stepwise logistic regression was performed controlling for patient demographics, medical history, and preoperative medications to determine whether obesity was independently associated with an increased risk of adverse postoperative outcomes.

Results: Obesity in nondiabetic patients was not independently associated with an increased risk of adverse postoperative outcomes. In contrast, obesity in diabetic patients was independently associated with a significantly increased risk of postoperative respiratory failure (odds ratio [OR], 2.26; 95% confidence interval [CI], 1.41-3.61; P < 0.001), ventricular tachycardia (OR, 2.27; 95% CI, 1.18-4.35; P < 0.02), atrial fibrillation (OR, 1.56; 95% CI, 1.03-2.38; P < 0.04), atrial flutter (OR, 2.38; 95% CI, 1.29-4.40; P < 0.01), renal insufficiency (OR, 1.66; 95% CI, 1.10-3.41; P < 0.03), and leg wound infection (OR, 5.34; 95% CI, 2.27-12.54; P < 0.001). Obesity in diabetic patients was not independently associated with an increased risk of mortality, stroke, myocardial infarction, sepsis, or sternal wound infection.     

Mediation of nitrous oxide analgesia in mice by spinal and supraspinal kappa-opioid receptors

Exposure to nitrous oxide produced concentration-dependent analgesia in the mouse abdominal constriction test. Intracerebroventricular or intrathecal pretreatment with naltrexone or nor-binaltorphimine significantly reduced nitrous oxide analgesia. However, similar pretreatment with beta-funaltrexamine had no appreciable effect. These findings suggest that nitrous oxide analgesia involves spinal and supraspinal kappa-opioid receptors.     

Culture of menstrual endometrium with peritoneal explants and mesothelial monolayers confirms attachment to intact mesothelial cells

BACKGROUND: To evaluate adhesion of menstrual endometrium (ME) to intact peritoneal mesothelium. METHODS: Explants of peritoneum were cultured for 1 h with ME (n = 6). Specimens were serially sectioned for haematoxylin and eosin stain and immunohistochemistry using an anti-cytokeratin antibody to label mesothelium. Confocal laser scanning microscopy (CLSM) was performed to identify an intact layer of mesothelial cells (MC) underlying sites of ME attachment. Also, ME and MC were labelled with Cell-Tracker dyes. ME was cultured with mesothelial monolayers for 1 h (n = 10). Cultures were examined with differential interference contrast and CLSM. Optical sections were taken and a three-dimensional model was constructed. RESULTS: In the peritoneal explants, ME adhered to intact mesothelium. There was no evidence of transmesothelial invasion. CLSM of sections of the explants demonstrated an intact monolayer of cytokeratin positive cells below the sites of ME implantation. Cytokeratin negative and positive ME cells adhered to mesothelial cells. Likewise, the ME attached to cultured mesothelium. Orthogonal sections and three-dimensional reconstruction confirmed an intact monolayer of mesothelium underlying ME attachment sites. CONCLUSIONS: This study confirms that ME adheres rapidly to intact peritoneal mesothelium. Further studies are needed that characterize the mechanisms of ME adhesion to, and migration through, mesothelial cells.     

Clinical and Epidemiological Relevance of Quantitating Hepatitis E Virus-Specific Immunoglobulin M

Diagnosis of acute hepatitis E by detection of hepatitis E virus (HEV)-specific immunoglobulin M (IgM) is an established procedure. We investigated whether quantitation of HEV IgM and its ratio to HEV total Ig furnished more information than conventional IgM tests that are interpreted as positive or negative. A previously described indirect immunoassay for total Ig against a baculovirus-expressed HEV capsid protein was modified to quantitate HEV-specific IgM in Walter Reed (WR) antibody units by using a reference antiserum and the four-parameter logistic model. A receiver-operating characteristics curve derived from 197 true-positive specimens and 449 true-negative specimens identified 30 WR units/ml as an optimum cut point. The median HEV IgM level in 36 patients with acute hepatitis E fell from 3,000 to 100 WR units/ml over 6 months, suggesting that 100 WR units/ml would be a more appropriate cut point for distinguishing recent from remote IgM responses. Among three hepatitis E case series, determination of the HEV IgM-to-total-Ig ratio in acute-phase serum revealed that most patients had high ratios consistent with primary infections whereas a few had low ratios, suggesting that they had sustained reinfections that elicited anamnestic antibody responses. The diagnostic utility of the new IgM test was similar to that of a commercially available test that uses different HEV antigens. In conclusion, we found that HEV IgM can be detected specifically in >95% of acute hepatitis E cases defined by detection of the virus genome in serum and that quantitation of HEV IgM and its ratio to total Ig provides insight into infection timing and prior immunity.     

Y chromosome microdeletions, in azoospermic or near-azoospermic subjects, are located in the AZFc (DAZ) subregion

Submicroscopic deletions of the Y chromosome and polymorphisms of the androgen receptor (AR) gene in the X chromosome have been observed in men with defective spermatogenesis. To further define the subregions/genes in the Y chromosome causing male infertility and its relationship to polymorphisms of the AR polyglutamine tract, we screened the genomic DNA of 202 subfertile males and 101 healthy fertile controls of predominantly Chinese ethnic origin. Y microdeletions were examined with 16 sequence-tagged site (STS) probes, including the RBM and DAZ genes, spanning the AZFb and AZFc subregions of Yq11, and related to the size of trinucleotide repeat encoding the AR polyglutamine tract. Y microdeletions were detected and confirmed in three out of 44 (6.8%) of azoospermic and three out of 86 (3.5%) severely oligozoospermic patients. No deletions were detected in any of the patients with sperm counts of >0.5 x 10(6)/ml, nor in any of the 101 fertile controls. All six affected patients had almost contiguous Y microdeletions spanning the entire AZFc region including the DAZ gene. The AZFb region, containing the RBM1 gene, was intact in five of the six subjects. Y deletions were not found in those with long AR polyglutamine tracts. Our study, the first in a Chinese population, suggest a cause and effect relationship between Y microdeletions in the AZFc region (possibly DAZ), and azoospermia or near-azoospermia. Y microdeletions and long AR polyglutamine tracts appear to be independent contributors to male infertility.      

A 2-week efficacy and safety study of eszopiclone in elderly patients with primary insomnia

STUDY OBJECTIVES: Evaluate the efficacy of eszopiclone in primary insomnia. DESIGN/SETTING: Randomized, double-blind, placebo-controlled multicenter in outpatient setting with weekly visits. PARTICIPANTS: Two-hundred thirty one men and women aged 65 to 85 years (mean age 72.3 years) with primary insomnia, as defined by the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition. INTERVENTIONS: Eszopiclone 1 mg (n = 72), eszopiclone 2 mg (n = 79), or placebo (n = 80) nightly for 2 weeks. MEASUREMENTS/RESULTS: Efficacy was assessed using an interactive voice response system. Following the predefined hierarchical testing strategy, the eszopiclone 2-mg group had a significantly shorter sleep latency compared with placebo over the double-blind period (P = .0034). The eszopiclone 2-mg group had significantly longer total sleep time (P = .0003) and eszopiclone 1-mg group had significantly shorter sleep latency (P < or = .012) compared with placebo. The eszopiclone 1-mg group was not significantly different from placebo on total sleep time or any other secondary efficacy endpoint. Secondary analyses indicated that the eszopiclone 2-mg group had significantly less wake after sleep onset; significantly fewer and shorter in duration daytime naps; and significantly higher ratings of sleep quality and depth, daytime alertness, and sense of physical well-being compared with placebo (P < .05). Eszopiclone was well tolerated. The most frequent treatment-related adverse event was unpleasant taste. CONCLUSION: Nightly treatment with eszopiclone 1 mg effectively induced sleep, while the 2-mg dose was effective in inducing and maintaining sleep. Eszopiclone was well tolerated in elderly patients with primary insomnia, and the sleep efficacy was accompanied by significantly less napping and significantly higher ratings of daytime alertness, sense of physical well-being, and several quality-of-life parameters at the higher dose.     

Development of a larval bioassay for susceptibility of cat fleas (Siphonaptera: Pulicidae) to imidacloprid

Strategies for controlling cat fleas, Ctenocephalidesfelisfelis (Bouché), have undergone dramatic changes in the past 5 yr. With the advent of on-animal treatments with residual activity the potential for the development of insecticide resistance increases. A larval bioassay was developed to determine the baseline susceptibility of field-collected strains of cat fleas to imidacloprid. All four laboratory strains tested showed a similar level of susceptibility to imidacloprid. Advantages of this bioassay are that smaller numbers of fleas are required because flea eggs are collected for the test. Insect growth regulators and other novel insecticides can also be evaluated. Using a discriminating dose, the detection of reduced susceptibility in field strains can be determined with as few as 40 eggs.