Disruption of DNA-PK in Ku80 mutant xrs-6 and the implications in DNA double-strand break repair

To determine the usefulness of a GnRH agonist analog as a diagnostic test to distinguish between constitutional delay of growth (CGD) in boys with Tanner stage I of sexual development and patients with hypogonadotropic hypogonadism (HH), we evaluated six boys (mean age 15 yr 4 m) and five HH patients (mean age 20 yr 4 m). In addition, 20 normal healthy men aged 21 yr to 50 yr received either nafarelin or GnRH followed two weeks later by the other test in order to compare the efficacy of each of these tests and to evaluate the optimal sampling times for the nafarelin test. All subjects were healthy, and had not received hormonal replacement for at least 2 months prior to enrollment in the study. Each man had four baseline blood samples before and at timed intervals following the administration of either GnRH or nafarelin. Each of the patients had blood withdrawn every 15 min during 12 h overnight followed by a single s.c. injection of nafarelin (1 microgram(s)/kg up to 100 microgram(s)), except two HH patients who did not have an overnight study. Blood samples were obtained at timed intervals for 24 h. LH, FSH, T and E2 were measured by RIA. Baseline concentrations of plasma LH, FSH and T were similar before the administration of either GnRH or nafarelin in the group of normal men. Peak stimulation of plasma LH, FSH and T released by nafarelin was significantly higher, and it took a longer time to reach the peak maximum, than after GnRH (p < 0.001). Mean nocturnal LH was 5.5 +/- 0.9 IU/I for the CGD group, and 2.7 +/- 0.7 IU/I for HH (p < 0.02). Mean nocturnal FSH was 5.1 +/- 1.0 and 2.5 +/- 0.2 IU/I whereas mean nocturnal T concentrations were 4.2 +/- 0.8 and 0.7 +/- 0.2 nmol/I (CGD vs HH, respectively, p < 0.02). Peak LH responses to nafarelin were 36.9 +/- 8.9 IU/I for the CGD group, and 7.0 +/- 2.0 IU/I for the HH group (p < 0.001). Peak FSH released by nafarelin was 14.2 +/- 2.4 IU/I for the CGD group and 4.8 +/- 2.0 IU/I for the HH group (p < 0.02). Peak T was reached 24 h following nafarelin injection and was 5.7 +/- 1.7 nmol/I for the CGD group and 0.3 +/- 0.2 nmol/I for the HH group (p < 0.001). The results obtained indicate that in early stages of puberty (before detectable changes of sexual maturation) the nafarelin test, with measurements of LH, FSH and T in blood or in urine, is superior to and more practical than overnight hormonal estimates to clearly distinguish CGD from HH.     

The feeding value of soybeans fed to rats, chickens, catfish and dairy cattle is not altered by genetic incorporation of glyphosate tolerance

Animal feeding studies were conducted with rats, broiler chickens, catfish and dairy cows as part of a safety assessment program for a soybean variety genetically modified to tolerate in-season application of glyphosate. These studies were designed to compare the feeding value (wholesomeness) of two lines of glyphosate-tolerant soybeans (GTS) to the feeding value of the parental cultivar from which they were derived. Processed GTS meal was incorporated into the diets at the same concentrations as used commercially; diary cows were fed 10 g/100 g cracked soybeans in the diet, a level that is on the high end of what is normally fed commercially. In a separate study, laboratory rats were fed 5 and 10 g unprocessed soybean meal 100 g diet. The study durations were 4 wk (rats and dairy cows), 6 wk (broilers) and 10 wk (catfish). Growth, feed conversion (rats, catfish, broilers), fillet composition (catfish), and breast muscle and fat pad weights (broilers) were compared for animals fed the parental and GTS lines. Milk production, milk composition, rumen fermentation and nitrogen digestibility were also compared for dairy cows. In all studies, measured variables were similar for animals fed both GTS lines and the parental line, indicating that the feeding value of the two GTS lines is comparable to that of the parental line. These studies support detailed compositional analysis of the GTS seeds, which showed no meaningful differences between the parental and GTS lines in the concentrations of important nutrients and antinutrients. They also confirmed the results of other studies that demonstrated the safety of the introduced protein, a bacterial 5-enolpyruvyl-shikimate-3-phosphate synthase from Agrobacterium sp. strain CP4.     

Acute and chronic effects of insulin on leptin production in humans: Studies in vivo and in vitro

This study was undertaken to investigate the changes in obesity (OB) gene expression and production of leptin in response to insulin in vitro and in vivo under euglycemic and hyperglycemic conditions in humans. Three protocols were used: 1) euglycemic clamp with insulin infusion rates at 40, 120, 300, and 1,200 mU / m / min carried out for up to 5 h performed in 16 normal lean individuals, 30 obese individuals, and 31 patients with NIDDM; 2) 64-to 72-h hyperglycemic (glucose 12.6 mmol/l) clamp performed on 5 lean individuals; 3) long-term (96-h) primary culture of isolated abdominal adipocytes in the presence and absence of 100 nmol/l insulin. Short-term hyperinsulinemia in the range of 80 to > 10,000 microU/ml had no effect on circulating levels of leptin. During the prolonged hyperglycemic clamp, a rise in leptin was observed during the last 24 h of the study (P < 0.001). In the presence of insulin in vitro, OB gene expression increased at 72 h (P < 0.01), followed by an increase in leptin released to the medium (P < 0.001). In summary, insulin does not stimulate leptin production acutely; however, a long-term effect of insulin on leptin production could be demonstrated both in vivo and in vitro. These data suggest that insulin regulates OB gene expression and leptin production indirectly, probably through its trophic effect on adipocytes.     

Effective treatment of narcolepsy with codeine in a patient receiving hemodialysis

We evaluated the effect of endothelin-1 (ET) on the angiotensin converting enzyme (ACE) activity in rat aortic smooth muscle cells (VSMCs). ACE activity was determined by radioimmunoassay of the amount of angiotensin II generated after the addition of angiotensin I (500 pg/ml) to cultured VSMCs. The antibody used had less than 0.1% cross-reactivity with angiotensin I. ACE activity increased 1.9-fold 5 hr after the addition of 10(-6) M ET under serum-free conditions. This stimulatory effect of ET on ACE activity in VSMCs was completely inhibited by 10(-7) M captopril. Results suggested that the ACE present in SMCs is stimulated by ET.     

Patterns of esophageal motility in patients with stable bulimia

OBJECTIVES: A high prevalence of GI motility disturbances, including deranged esophageal motility, has previously been reported in patients with eating disorders; altered esophageal and gastric motility have been suggested to play an important role in these disease processes. We sought to confirm this association in an independent patient population. METHODS: We performed esophageal manometry in 12 patients with eating disorders (eight patients with bulimia and four with overlap syndromes, including both anorexia and bulimia features) and 12 sex-matched controls. All subjects completed a symptom questionnaire. Motility testing was performed in the standard fashion using a low compliance water perfusion catheter and computerized digital data capture. Coded tracings were interpreted in a blinded fashion. RESULTS: All 24 studies showed normal motility patterns [95% confidence interval for abnormal esophageal motility in eating disorders patients (0, 0.27)]. Mean lower esophageal sphincter pressure was 24.4 mm Hg in patients and 21.8 in controls; all relaxed normally. Mean esophageal body contraction amplitude 3 cm above the lower esophageal sphincter was 82.6 mm Hg in patients and 84.3 in controls; waveform morphology and progression met normal criteria in all studies. Eight of 12 patients reported dysphagia, odynophagia, or both, compared with 1 of 12 controls; patients demonstrated a pattern of increased overall GI symptomatology compared to controls. CONCLUSIONS: We conclude that disordered esophageal motility is uncommon among stable eating disorder outpatients with bulimic features, and that dysphagia and odynophagia are rarely associated with disordered motility in this group.     

Borrelia burgdorferi erpT expression in the arthropod vector and murine host

The expression of a Borrelia burgdorferi gene, erpT, was investigated throughout the spirochaete life cycle in the arthropod vector and the murine host. Three phage clones from a B. burgdorferi DNA expression library synthesized a 30 kDa antigen that was recognized by antibodies in the sera of B. burgdorferi-infected mice but not mice hyperimmunized with B. burgdorferi lysates. Differential antibody binding suggested that this protein was preferentially expressed in vivo. This antigen was designated ErpT, based upon 99.6% homology with the BBF01 sequence in the B. burgdorferi genome. ErpT was not detected on spirochaetes cultured in BSK II medium by indirect immunofluorescence or in B. burgdorferi lysates by immunoblotting, implying that ErpT is not readily produced in vitro. erpT mRNA was not discernible by Northern blot but was identified by RNA polymerase chain reaction in vitro, indicating that erpT is expressed at low levels by cultured spirochaetes. erpT expression was then investigated in the vector and mice because B. burgdorferi do not normally reside in culture medium. RNA polymerase chain reaction and immunofluorescence studies demonstrated that erpT was expressed by a small minority of B. burgdorferi (11/500, 2.2%) within unfed ticks and then repressed during engorgement. erpT mRNA or ErpT antibodies were first detected in B. burgdorferi-infected mice at 4 weeks, suggesting that erpT was not expressed in the early stages of murine infection. Then, during persistent infection, RNA polymerase chain reaction showed that erpT was expressed by B. burgdorferi within the joints, heart and spleen, but not by spirochaetes in the skin. Immunization of mice with ErpT was antigenic but was not protective. These studies demonstrate that B. burgdorferi erpT is differentially expressed throughout the B. burgdorferi life cycle, in both the vector and the mammalian host, and is primarily expressed in extracutaneous sites during murine infection.     

X-Linked agammaglobulinemia patients are not infected with Epstein-Barr virus: implications for the biology of the virus

Epstein-Barr virus (EBV) infects both B lymphocytes and squamous epithelial cells in vitro, but the cell type(s) required to establish primary and persistent infection in vivo has not been definitively elucidated. The aim of this study was to investigate a group of individuals who lack mature B lymphocytes due to the rare heritable disorder X-linked agammaglobulinemia in order to determine the role of the B cell in the infection process. The results show that none of these individuals harbored EBV in their blood or throat washings. Furthermore, no EBV-specific memory cytotoxic T lymphocytes were found, suggesting that they had not undergone infection in the past. In contrast, 50% of individuals were found to carry human herpesvirus 6, showing that they are infectible by another lymphotropic herpesvirus. These results add weight to the theory that B lymphocytes, and not oropharyngeal epithelial cells, may be required for primary infection with EBV.     

Enantioselective analysis of N-hydroxymexiletine glucuronide in human plasma for pharmacokinetic studies

CO2 reactivity of cerebral hemoglobin concentration was studied in 16 healthy term neonates on days 1 and 4 after birth using the near infrared spectrophotometry (NIRS) technique. The aim was to establish data on the physiological range of CO2 reactivity in healthy newborns and to investigate the influence of postnatal age on it. The CO2 reactivity measured by NIRS is expressed as the change of the total cerebral hemoglobin concentration (tHbR) per change of CO2 tension in micromol/l/kPa. We evaluated CO2 reactivity during increases and decreases of transcutaneous CO2 partial pressure and found in our methodological setting the data of the increases more reliable. In all infants but 1 we found a tHbR on day 1 with a mean value of 8.19 micromol/l/kPa (-1.39 to 18.87), in all infants on day 4 with a mean value of 9.54 micromol/l/kPa (2.76-25. 88). There is a trend to higher values between day 1 and day 4 (difference = 2.25 micromol/l/kPa; p = 0.08). The noninvasive NIRS technique enabled us to test the cerebrovascular CO2 reactivity of the tHbR for the first time in healthy term newborns. Data on its physiologic range and variability are presented and compared to findings from ventilated infants and other age groups. As the CO2 reactivity might be an indicator for infants at risk of cerebral damage, it is necessary to have data on the physiological range of this parameter.