A simplified method of counting microorganisms in studying human autoflora

Formulae for the calculation of the count of microorganisms isolated from natural bacterial biocenoses of a child's body have been derived. The authors suggest a variant of simplified drip method for the computation of microorganism colonies in solid media. The described method helps cut down the nutrient media consumption at least 3-fold and is time-saving.     

Wall-thickness and midwall-radius variations in ventricular mechanics.

A fluid-fiber-collagen stress tensor is used to describe the rheology of the left ventricle of the heart. Linear theory is used to find the equilibrium solutions for the end-diastolic and end-systolic states of general axisymmetric shapes that are small perturbations of a thick-walled finite cylinder. The general problem can be studied by superposing the effects of variable midwall radius but constant wall thickness with those of variable wall thickness but constant midwall radius. A Fourier series representation is used to describe the midwall radius and thickness functions. Numerical calculations are performed to determine the deformed geometry and spatial distributions of tissue pressure, stresses, and fiber strains. The calculations proved to be highly accurate when compared to an analytical solution obtained for the special case of no fibers. The results show significant longitudinal differences when compared to results for the cylindrical geometry, with more sensitivity to variation in wall thickness than to variation in midwall radius.     

Value of continuous monitoring of the electrocardiogram in asymptomatic subjects

The authors analysed the prevalence of atrioventricular conduction defects and sinus node dysfunction by Holter monitoring in three population groups with similar clinical characteristics: 50 controls (Group I), 17 physically fit subjects with an atrioventricular conduction defect on the resting ECG which was usually asymptomatic (Group II), and 48 professional pilots who were also physically fit but who had no conduction defects on resting ECG (Group III). The 24 hour recordings showed: --a similar incidence of sinus dysrhythmias and atrioventricular conduction defects in the three groups although the frequency of low degree block was a little higher in sportsmen; --a preponderance of the association of first degree block and nocturnal Luciani-Wenckebach periods, sometimes with episodes of Mobitz II block; --the absence of progression to high-degree atrioventricular block. Holter monitoring would therefore seem to be a good method of detecting and following up abnormalities of sinus node function and atrioventricular conduction defects in asymptomatic patients. In addition, it gives a qualitative and quantitative assessment of the recorded changes and provides a means of monitoring their evolution.     

Reassessment of enkephalin (ENK)-containing afferents to the rat lateral septum with reference to the fine structures of septal ENK fibers

Using a combination of horseradish peroxidase (HRP) histochemistry and immuno-beta-galactosidase staining, and pre-embedding immuno-electron microscopy, the present study was intended to re-examine the origins of enkephalin-like immunoreactivity (ENKI) in the rat lateral septum (LS), and to show the fine structures of septal ENKI fibers. Following HRP injection into the LS, double-labeled cells which contained a homogeneous blue reaction product of ENKI and a black or brown granular reaction product of retrogradely transported HRP were identified in 4 discrete brain regions: perifornical hypothalamic area at the level of the paraventricular nucleus (PeF); posterior part of the anterior hypothalamic nucleus (AHP); bed nucleus of the stria terminalis, medial division, posterolateral part (BSTMPL); and dorsal hypothalamic area (DA). Immuno-electron micrographs demonstrated that some of the ENKI terminals in the LS form synapses with the soma and dendrites of septal neurons devoid of ENKI, though ENKI dendrites postsynaptic to non-immunoreactive terminals were also seen in the LS. These findings suggest that a large proportion of septal ENKI fibers have their origins in the above regions (PeF, AHP, BSTMPL, DA) different from the previously considered one, and they further provide a morphological basis for the postsynaptic inhibitory effects of enkephalins on septal neurons.     

Maternal factors influencing development of embryos from mice superovulated with gonadotropins

In NMRI mice superovulation with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) increased mating rate, number of implantation sites, rate of advanced and delayed resorptions, as well as retarded sternebral ossification and cleft palate. On day 3 of gestation in preimplantation embryos, cell number and mitotic index were lower after superovulation than after spontaneous ovulation. However, when preimplantation embryos from superovulated and control females were transferred on day 3 of pregnancy to pseudopregnant recipients (10 embryos per female) no differences could be detected between the two groups of fetuses at term. The results of the embryo transfer experiments indicate that abnormal embryonic development after superovulation with gonadotropins is predominantly induced by effects of the hormone treatment on the maternal uterine environment.     

Effect of estrogen on calcium homeostasis and pituitary hormones in the growing chick

An experiment was carried out to investigate the effect of a range of estradiol (E2) doses (0.1-6.5 micrograms/g body wt/day) on vitamin D metabolism and the plasma levels of growth hormone (GH) and prolactin (PRL) in the growing chick. Doses of 0.5-0.7 microgram/g E2, which are insufficient to raise the plasma calcium level, did induce an increase in growth rate, an increase in 25-hydroxyvitamin D 1 alpha-hydroxylase (1-hydroxylase) and 24-hydroxylase activities, and an increase in plasma GH level. These parameters leveled off or fell over the dose range 1-2 micrograms/g E2 but there was evidence of a second peak in 1-hydroxylase activity at 6 micrograms/g E2. At this high dose rate, the plasma Ca level rose to 8 mM, as it does in the laying hen; 24-hydroxylase activity, growth rate, and plasma GH and plasma PRL levels all decreased. It was concluded that the dose response to estrogen in the growing chick is not linear and, in the case of 1-hydroxylase activity, may even be biphasic.     

Hospital charges: analysis and comparison

The validity of studies comparing charges between hospitals is threatened by differences in hospital case mix and severity of illness within diagnoses. The method presented here uses readily available Blue Cross claims data to make interhospital comparisons of charges.     

Antibacterial activities of the leaf extracts of Eugenia uniflora Linn. (Synonym Stenocalyx michelli Linn.) Myrtaceae

The aqueous, organic, and volatile oil extracts of leaves of Eugenia uniflora Linn. Family Myrtaceae were investigated for antibacterial properties using agar dilution techniques. The aqueous extract was the most active against the organisms compared to the organic and volatile oil extracts. The extracts were found to inhibit Gram positive Staphylococcus aureus and Bacillus subtilis and Gram negative Escherichia coli and Shigella dysentcriae. Pseudomonas aeruginosa, Klebsiella pneumoniac, and Salmonella typhi were not inhibited.     

The complex nature of the mechanism of toxicity of antibiotic dithiacyclohexadiene polyines (thiarubrines) from the asteraceae

Thiarubrine A, a dithiacyclohexadiene polyine from the roots of Chaenactis douglasii, and a related dithiacyclohexadiene from Rudbeckia hirta exhibit strong light-independent antibacterial and antifungal activity. This activity is enhanced by exposure to visible light. Visible light also converts the compounds to the corresponding thiophenes. These are antibiotic only when irradiated with UV-A. Dithiacyclohexadienes are the first polyines to exhibit such complex mechanisms of toxicity towards microorganisms.