Differences in the temporal dynamics of the visual ON and OFF pathways

The temporal structure of spike trains recorded from optic fibers and single units of the lateral geniculate nucleus (LGN) and primary visual cortex of the cat was studied with a novel method of inter-spike interval analysis. ON type relay cells of the LGN exhibited a multimodal interval distribution preferring a distinct interval (fundamental interval) and its multiples during the sustained light response, whereas most OFF cells showed a broad, unimodal distribution. The general pattern of the interval distribution was relatively independent of stimulus size and contrast and the degree of light adaptation. Simultaneously recorded S-potentials originating from the retinal input generally produced only a single peak at the fundamental interval length. Therefore, the multimodal interval distribution of LGN cells seems to be a result of intra-geniculate inhibition. Cortical cells also showed a weak tendency to fire with spike intervals similar to LGN cells. Therefore, the regular firing pattern observed at peripheral stages of the visual pathway can persist at higher levels and might promote the occurrence of oscillatory activity.     

In vivo effects of an acute nonimmunological inflammation in rats on the lymphoproliferative response to mitogens

Lymphoid cells (spleen, lymph node and thymus) derived from rats after induction of an acute nonimmunological inflammatory reaction responded to various mitogens (Phytohemagglutinin, PHA; Concanavalin A, Con A; Lipopolysaccharide, LPS) with increased proliferation when compared with cells derived from normal animals. In the absence of mitogens, lymphoid cells from animals undergoing an acute nonimmunological inflammation demonstrated enhanced proliferation compared with cells from normal animals. These results clearly demonstrated that during acute nonimmunological inflammation the reactivity of lymphoid cells was increased.     

Modulation of immune responses in mice by oral administration of niflumic acid

The in vivo effects of non-steroidal anti-inflammatory drugs (NSAIDs) on the host immune system are still poorly understood. However, through inhibition of prostaglandin synthesis, NSAIDs may exhibit immunomodulating properties. The present work was aimed at evaluating the influence of niflumic acid on immune responses when administered orally for 7 consecutive days to 8-week-old inbred mice. Immunological tests were performed 24 h after the arrest of the treatment. At a dosage of 50 mg/kg/day, niflumic acid exerted noticeable immunostimulating effects, as shown by an increase in plaque-forming cell numbers after in vivo immunization with sheep red blood cells, an augmentation of spleen cell proliferation responses to stimulation with T- or B-cell mitogens and of T-cell cytotoxic response to allogenic cells. Phagocytosis-induced chemiluminescence of peritoneal macrophages was also enhanced whereas interleukin-1 production by these cells was depressed, but without concomitant modification in interleukin-2 production by T-cells. Increasing the niflumic acid dosage to 75 mg/kg resulted in the disappearance of the immunostimulatory effects on lymphocytes responses. Macrophage activities were affected similarly in mice receiving 50 mg/kg. These results demonstrate that niflumic acid is able to stimulate in vivo several immunological functions and, consequently, to maintain host immune defenses. Interestingly, it depressed interleukin-1 production, known to play a major role in the inflammatory process.     

Normal metabolism of apolipoprotein B100-containing lipoproteins despite qualitative abnormalities in type 1 diabetic men

Aims/hypothesis Type 1 diabetic subjects are at increased risk of cardiovascular disease and exhibit multiple qualitative abnormalities of apolipoprotein (apo) B100-containing lipoproteins. This stable isotope kinetic experiment was designed to study whether these abnormalities are associated with changes in the synthesis and fractional catabolic rates of VLDL-, IDL- and LDL-apoB100.Methods Using a bolus followed by a 16-h constant infusion of ¹³C-leucine, we performed a kinetic study in eight men with type 1 diabetes treated with a continuous subcutaneous insulin infusion administered by an external pump and in seven healthy men, in the fed state.Results The mean HbA₁c level in the type 1 diabetic patients was 8.00±1.48%. Plasma triglyceride, and total, LDL and HDL cholesterol levels were similar in patients and control subjects. VLDL were less triglyceride rich in type 1 diabetic patients than in control subjects (VLDL triglyceride : apoB 6.91±0.81 vs 8.29±1.24 mmol/g, p=0.05). Conversely, the IDL and LDL of the type 1 diabetic patients contained relatively higher levels of triglycerides (IDL triglycerides : apoB 2.16±0.36 vs 1.57±0.30 mmol/g, p<0.01; LDL triglycerides : apoB 0.27±0.06 vs 0.16±0.04 mmol/g, p<0.05). The apoB100 pool size, production and fractional catabolic rates in the two groups of subjects were similar for all lipoprotein fractions.Conclusions/interpretation Despite qualitative abnormalities, especially abnormalities of triglyceride content, the metabolism of apoB100-containing lipoproteins is not altered in type 1 diabetic men with fair glycaemic control with continuous subcutaneous insulin infusion. The high risk of atherosclerosis in these patients cannot be explained by kinetic abnormalities of apoB100-containing lipoproteins.     

No detection of Besnoitia besnoiti DNA in the semen of chronically infected bulls

Bovine besnoitiosis is a chronic and debilitating disease observed in many European countries that may cause important economic losses in cattle. The recent widespread of the parasite in Europe had led the European Food Safety Authority to declare bovine besnoitiosis as a re-emerging disease in Europe. Many aspects of the epidemiology of bovine besnoitiosis such as the main routes of transmission are still unclear and need to be further studied. Among the different hypotheses, a sexual transmission has not yet been investigated. Therefore, the aim of this study was to evaluate the presence of Besnoitia besnoiti DNA in the semen of naturally infected bulls by using a highly sensitive method (real-time qPCR). Both pre-sperm and sperm fractions of 40 bulls, including seronegative (n?=?11), seropositive subclinically (n?=?17), and seropositive clinically (n?=?12) infected animals, were collected by electroejaculation and analyzed by real-time qPCR. No B. besnoiti DNA was detected in 27 pre-sperm and 28 sperm fractions of the 40 examined bulls, suggesting that the transmission of B. besnoiti infection by the semen of chronically infected bulls is very unlikely.     

Hepatitis A among health workers in Paris hospitals. Occupational Health Physicians of Paris Hospital (AP-HP).

To design a vaccination strategy against hepatitis A among hospital employees, we carried out a serological survey of hepatitis A virus (HAV) infection in 10 university hospitals in the Paris area. Subjects under 60 years of age were consecutively enrolled by occupational health services and tested for IgG to HAV by ELISA. Of the 1,516 subjects recruited, 926 were health workers (HW), 322 clerks, and 268 cooks or kitchen employees. Among HW and clerks the HAV seroprevalence was 53.8% (95% CI: 44.0-65.6), increasing with age and being higher among employees of African or Caribbean origin than those from Europe (83.6% vs 45.6%, P < .001). Age correlated closely with the duration of hospital work, so only age was taken into account for further analysis. The HAV seroprevalences among HW and clerks originating from Europe were close (46.8% vs 42.6%) and remained so after adjustment for age. HAV seroprevalences in HW caring for adults and those caring for children were also similar (45.2% vs 40.1%). Seroprevalence was higher in assistant nurses than in nurses (51.3% vs. 39.8%, P < .02). Among cooks and kitchen employees, 53.4% were HAV-seropositive. This study shows that hospital employees need not routinely be vaccinated against HAV; the decision should be taken by the occupational physician according to the type of work, but should be routine for cooks and kitchen employees. The need for prevaccinal screening for anti-HAV should be assessed in the light of employees' geographical origin and age.     

In vitro effect of an acute nonspecific inflammatory exudate on tritiated-thymidine incorporation by unstimulated and PHA-stimulated spleen cells.

The effect of an acute nonspecific inflammatory exudate with mitogenic activity for macrophages in culture has been tested on the spontaneous and PHA-induced DNA synthesis by spleen cells in vitro. Stimulatory effect of this exudate was observed on the spontaneous DNA synthesis which was detectable over a range of 1:4 to 1:4096 concentrations. After optimal PHA stimulation, an inhibition of mitogen-induced DNA synthesis was observed when the cells were exposed to the highest concentrations (up to 1:128) of the exudate. Thereafter, the phenomenon could be reversed and the stimulation was maximal at the concentration of 1:2048. When a suboptimal dose of PHA was used, the stimulatory effect was more pronounced and detected from 1:8 up to 1:4096 concentrations.     

Prenatal diagnosis of common aneuploidies using quantitative fluorescent PCR

OBJECTIVE: Quantitative fluorescence-polymerase chain reaction (QF-PCR) has recently been used for the detection of common chromosomal aneuploidies in prenatal diagnosis. Here we describe our experience in prenatal diagnosis of 1100 samples. METHODS: Extraction of DNA was performed from amniotic fluid, chorionic villus samples (CVS), fetal blood and fetal tissue samples, using a simple, rapid protocol. Fluorescent multiplex PCR products of single tandem repeats (STRs) located on chromosomes 13, 18, 21, X and Y were then analyzed on an automated laser fluorescent sequencer. All samples were analyzed with at least two polymorphic markers for chromosomes 13, 18 and 21 and one for the X chromosome. The amelogenin locus was used for sexing. Analysis was performed twice on affected samples. When miscellaneous results were obtained extra markers were used. RESULTS: We evaluated the usefulness of different markers in the Greek population. In a total of 1100 samples, 25 chromosome aberrations were identified, including trisomy 13, 18 and 21, XYY, triploidies 69,XXX and 69,XXY and one Turner mosaic. All results but three were consistent with conventional cytogenetic analysis. One mosaic was missed. Most bloodstained samples were successfully analyzed. CONCLUSION: Successful analysis of a large number of prenatal samples proves QF-PCR to be an efficient adjunct in routine prenatal diagnosis.