Quantitative aspects of the formation of a half chromatid chiasma as an intermediate product of genetic recombination in bacteriophages

Formal genetic consequences of generation and break-up of a half chromatid chiasma have been studied on the basis of a model with the symmetric exchange of two strands between parental DNA molecules. In recombination analysis, generation and break-up of this structure gives rise to a critical frequency R (zeta), which corresponds to recombination between two markers separated by a distance equal to the mean genetic length zeta of the hybrid region at the time of scission of the cross connection. The use of the distance zata as a natural unit of a genetic map is suggested. In the case of bacteriophage T4 under conditions of standard crosses the half chromatid chiasma is characterized by the value R (zata) equal to 3.0-10(-2), the structure acquiring with equal probability either of the two alternative isomeric configurations at the time of scission of the cross connection. About four per cent of the total number of mismatches as a result of break-up to the half chromatid chiasm were repaired.     

Chemical and pharmacological studies of Phyllanthus caroliniensis in mice

We studied retrospectively the effect of long-term treatment with an inhaled corticosteroid on bronchial hyperresponsiveness (BHR) and clinical asthma in moderate-severe asthmatic subjects. Fifty-eight patients who had used beclomethasone dipropionate (BDP) over one year, were enrolled in this study. BHR was measured before and after treatment with BDP by the methods recommended by Japanese Society of Allergology. Moreover we examined the clinical factors and the frequency of acute exacerbations. The results as follows: 1) The mean age was 48.8 years and the mean asthma history was 9.2 years. The mean dose and mean time of BDP administration was 801 micrograms/day and 28.1 months, respectively. 2) Patients during BDP treatment over one year showed about 6-fold mean improvements in BHR, but there were many patients who showed no improvements in BHR. 3) We retrospectively divided all the patients into two groups. Namely, the improved group (n = 25) showed more than 4 fold improvement in BHR and unchanged group (n = 33), less than 4-fold. But there were no significant differences in clinical characteristics and %FEV1 during treatment with BDP. 4) The unchanged group had more near fatal episodes in the past than the improved group. 5) There was significant decrease in acute exacerbation during treatment with BDP, but the unchanged group had more acute exacerbations than the improved group during treatment with BDP. These results indicates that there are many patients who had no improvement on BHR with long term BDP treatment and they have more acute exacerbations due to various stimuli. In conclusion, asthma is recognized chronic inflammatory disease and inhaled corticosteroid therapy has been recommended as the first line therapy. We must further study the clinical problems and underlying mechanisms concerning about treatment with an inhaled corticosteroid.     

Phlegmon of the stomach simulating a perforated ulcer

A new family of cytochrome P450 enzymes, CYP26, has been cloned and characterized in zebra fish, human, and mouse tissues. CYP26 displays specificity toward retinoic acid and it may function as an important regulator or differentiation and a possible modulator of disease states by controlling retinoid concentration and homeostasis.     

Role of nitric oxide in the inhibition of cytochrome P450 in the liver of mice infected with Chlamydia trachomatis

In this study, we attempted to determine the effect of a systemic infection with Chlamydia trachomatis on cytochrome P450(CYP)-dependent metabolism in mice. Furthermore, we wanted to assess if these effects were mediated through NO. BALB/c(H-2d) female mice were inoculated intraperitoneally with the C. trachomatis mouse pneumonitis (MoPn) biovar, and induction of NO synthase (NOS) was detected by measuring [NOx] levels and inducible NOS protein content in peritoneal macrophages by Western blotting. Recovery of C. trachomatis from liver, lung, and spleen peaked at 4 days postinfection. Following cotreatment with N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthase, there was a significant increase in the intensity and the length of the infection. Six days after inoculation with C. trachomatis, CYP1A- and CYP2B-mediated metabolism in the liver of the mice was diminished up to 49% of control levels. However, when animals were treated with N(G)-nitro-L-arginine methyl ester at days 4 and 6 postinfection, the decrease in the metabolism of CYP1A and CYP2B was largely blocked. These results suggest that C. trachomatis infection can depress cytochrome P450 in a manner similar to other types of infections and that NO is likely to be a mediator of this depression. This finding may be of significance to patients taking drugs that are metabolized by phase I enzymes during infections with some bacteria such as C. trachomatis.     

Primers for the nef gene in the diagnosis of HIV infection using the polymerase chain reaction

The incidence of chronic alcoholism among the non-medical staff of a hospital was evaluated in an occupational health service context. Three criteria were sought routinely: suspicion by history of excessive alcohol intake, typical findings by physical examination, and suggestive behavioural changes reported by work colleagues. Gamma glutamyl transpeptidase levels and mean corpuscular volume were measured when one of these three criteria existed. The diagnosis of chronic alcoholism was made when two criteria were found or when only one criterion existed but accompanied by laboratory abnormalities. The incidence of chronic alcoholism was 6.2 per cent among male staff and 0.6 among female staff. It appeared to be less than in the population as a whole. The selective and non-systematic use of laboratory investigations and the frequent absence of indication to the occupational health physician of behavioural problems were sources of bias which probably contributed to underestimation of the incidence of chronic alcoholism among employees of the Orleans Regional Hospital Group. Provision of information to all staff is essential in order to explain the behavioural changes associated with chronic alcoholism and the usefulness of reporting employees showing evidence of such changes to the occupational physician. This enables medico-social diagnosis and the early care of those with early chronic alcohol abuse.     

Pseudoainhum associated with plica neuropathica

Pseudoainhum due to mechanical factors is an uncommon occurrence in adults. A patient is described in whom continuous manipulation of the hair resulted in both a constricting band of hair around one finger and the unusual hair formation known as plica neuropathica. The result was near amputation of the finger.     

Energy balance and metabolic rate in preterm infants fed with standard and high-energy formulas

1. Energy balances were performed on sixteen low birth weight preterm infants over 7-10 d periods on a standard low-solute infant formula (2600 kJ/l), and on four high-energy formulas, providing different energy densities up to 3760 kJ/l. In two of the high-energy formulas the additional fat energy was provided by peanut oil, and the other two by medium chain triglycerides (MCT). Anthropometric measurements and metabolic rate (MR) determinations were made during the balance periods. 2. Mean energy retention on the standard formula was 66% of the intake and declined to below 50% on the two feeds providing the highest energy. Extensive energy balance data on the standard formula are available for reference. 3. Net absorption of dietary energy increased on all the high-energy formulas, rising from 362 kJ/kg per d on the standard formula to 453 kJ/kg per d on the highest energy-formula (P < 0.001). There was no advantage in using MCT. 4. Net absorption of dietary energy improved with advancing maturity, irrespective of the formula. 5. In spite of the increased dietary energy retention, there was no increase in growth rate during periods of feeding with the high-energy formulas. 6. Fasting and postprandial MR increased by 10.4 and 12.8% respectively on the highest energy feeds. 7. It is concluded that, at least in the short term, this type of high-energy feeding increases MR at the expense of growth and thus is probably of no advantage to the infant.