Genetic and cytogenetic marking of the neurological quaking mutation (qk) in laboratory mice

A new genetically balanced breeding system with a low recombination rate is offered for purposes of maintenance and early identification of mice with the recessive autosomal qk mutation. Dominant T mutation (Brachyury) and recessive t12 mutation of T locus were chosen as genetical markers and Robertsonian translocation Rb (8.17) 1 Iem served as a cytogenetical marker of the qk mutation. As shown by the results, none of genetical mutations studied (qk, T or t12) can be distinguished on differentially stained chromosomal preparations. Hybrid mice of the +T/qk+ genetic compound have a high rate (44%) of homozygous qk/qk offspring. The latter can be identified with the high probability (96%) in foetuses and newborns, according to their tail length, well before the typical neurological symptoms are evident. In the offspring of the F1 hybrids+Rb 1 Iem/qk+ the frequency of qk/qk mice is near 20% and they can be identified with the probability 95% at any stage of the development by means of chromosomal analysis. Hybrids of the +t12/qk genotype are very convenient for prolonged maintenance of the qk gene in a balanced heterozygous condition. Some features of functional similarities between the qk gene and recessive mutations of T locus are discussed. Genetical and cytogenetical markers used in this work provide some novel approaches for experimental analysis of the qk gene expression at early stages of the development.     

Space flight effects on skeletal bones of rats (light and electron microscopic examination)

In the light and electron microscopes, long tubular bones of Wistar rats that were flown for 22 d onboard the Cosmos-605 biosatellite and were exposed to a ground-based simulation experiment were examined. About half of the flight rats showed osteoporosis of metaphyses which was usually combined with a decrease of the mass of the primary spongiosa in the vicinity of the epiphyseal cartilaginous plate. This gives evidence that the growth of the bones could have been inhibited in flight. The light and electron microscopy of bones of flight rats revealed wide osteocyte lacunae which could have been produced by perilacunar osteolysis. In the simulation experiment, reduction in the metaphyseal spongiosa occurred only in one-third of the rats and was less pronounced than in flight rats; no decrease of the mass of the primary spongiosa near the cartilaginous plate was noted. Histological investigation of bones 27 d postflight demonstrated that that time period was not enough to eliminate all the changes in the bones tested.     

Differential diagnosis of allergic diseases of the upper respiratory tract

The author studied various manifestations of the most widely spread clinical forms of allergic diseases of the upper respiratory tract, namely, the bacterial, atopic and combined ones. In addition to clinical investigations laborotory, immunologic and functional tests were conducted. The difference in pathogenesis affected the clinical course of the disease. Some symptoms depended on the kind of sensibilization, others on how strongly pronounced the pathologic process was.     

Analysis of the quality of clinical diagnosis from generalized findings of the pathologoanatomic service

A statistical analysis of generalized data of the pathoanatomical service on quality of clinical diagnosis in curative-prophylactic institutions in 54 administrative territories of the RSFSR was carried out. The structure (extensive indices) and frequency (intensive indices)of erroneous clinical diagnoses referring to the most important classes of diseases were identified. As to the structure of indices and frequency of clinico-anatomic disparities the first place was occupied by oncological diseases (20.1+/-0.11 and 14.2+/-0.22%), the second--by infectious diseases (16.5+/-0.1 and 13.0+/-0.34%), the third--by diseases of the digestive system (14.6+/-0.09 and 13.0+/-0.33%), the forth--by diseases of the urogenital system (14.0+/-0.09 and 12.2+/-0.49%), the fifth--by disease of the respiratory system (12.7+/-0.09 and 10.6+/-0.24%), the sixth--by diseases of the cardiovascular system (11.1+/-0.08 and 8.0+/-0.14%). The recommendation is put forward to carry on annually a complex satistical analysis of extensive and intensive indices of erroneous clinical diagnoses demonstrating the quality of clinical diagnosis in therapeutic institutions of a given administrative territory.     

Is postextrasystolic potentiation dependent on Starling's law? Biplane angiographic studies in normal subjects

The cineangiograms of 26 normal subjects were analyzed to study the effect of Starling's mechanism on postextrasystolic potentiation. The end-diastolic volumes (single plane and biplane) of the left ventricle were similar in the regular sinus beat before an extrasystole and sequential sinus beats after an extrasystole. However, the ejection fraction, mean normalized systolic ejection rate, mean velocity of fiber shortening and long-axis shortening were consistently larger in the first sinus beat after an extrasystole. We conclude that postextrasystolic potentiation is independent of left ventricular end-diastolic volume in normal human hearts and the compensatory pause after an extrasystole does not result in increased end-diastolic volume.