FUNCTIONAL ASPECTS AND PATHOGENETIC CONSIDERATIONS OF THE NEUROPATHY IN THE SPONTANEOUSLY DIABETIC BB-WISTAR RAT

Sima A.A.F. & Hay K. (1981) Neuropathology and Applied Neurobiology 7, 341–350
Functional aspects and pathogenetic considerations of the neuropathy in the spontaneously diabetic BB-Wistar rat
Electrophysiological features were studied longitudinally in the spontaneously diabetic insulin-dependent, BB-Wistar rat. These were correlated in time with the state of the patency of the protective barriers in peripheral nerves. Motor nerve conduction velocity was significantly slowed only 3 weeks after the onset of the diabetes. When ultrastructural changes began, the maximal conduction velocity was further diminished. The amplitudes of evoked muscle potentials and distal latencies were significantly altered in diabetic rats. No change in the permeability of the blood-nerve barrier could be demonstrated before, during or after the onset of the nerve conduction defect. The possible pathogenetic mechanisms are discussed and a possible mechanism is suggested, namely a reduced availability of energy to axons in diabetes.     

Epidemiologic study of excessive oral melanin pigmentation with special reference to the influence of tobacco habits

Abstract – The prevalence of oral melanin pigmentation was studied in a population of 30 118 adult individuals in Sweden. Among these, 9.9% showed melanin pigmentation in the oral mucosa. The anterior labial gingiva in the mandible was the most frequently pigmented location. The presence of melanin pigmentation was positively correlated to tobacco smoking. Among tobacco smokers 21.5% were pigmented as compared to 3.0% among individuals not using tobacco. The smoking-rdated oral pigmentation, smokers' melanosis, could thus be calculated at a prevalence of 18.5% among smokers and the total frequency of smokers' melanosis was calculated at 6.8%. The prevalence of pigmentation was found to increase promninendy during the first year of smoking but aiso to decrease to the level found among non-tobacco users about 3 years after cessation of smoking. Snuff dipping did not significandy elevate the prevalence of oral melanin pigmentation.     

IMMUNOREACTIVE TRYPSIN SCREENING FOR CYSTIC FIBROSIS

ABSTRACT. Immunoreactive cationic trypsin (irCT) was measured in 22 cystic fibrosis (CF) and 132 control infants. IrCT was analysed with radioimmunoassay of dried blood samples collected for PKU screening around the 5th day of life and stored on filter paper. The mean ± 1 SD level of irCT for the control infants was 42±19 μg/l. Sixteen of the 22 CF children had an irCT level above 100 μg/l (mean + 3 SD) while 6 had a level at or below this cut-off limit. A specificity of 99%, which gives a sensitivity of 73%, and an approximative noise: signal ratio of 30: 1, suggests that the irCT test may be unsatisfactory as a neonatal screening method for CF.     

SENSORY NERVE CONDUCTION VELOCITY AS CORRELATED TO FIBRE SIZE IN EXPERIMENTAL UNDERNUTRITION IN THE RAT

The nerve conduction velocity was examined in sensory dorsal roots of pre- and postnatally undernourished and well-nourished control rats after supramaximal stimulation. Altogether forty-eight roots were examined: twenty-four from three undernourished rats 180 days of age, and twenty-four serving as controls from three well-nourished rats of the same age. It was found that the fastest sensory nerve conduction velocity was reduced in proportion to the reduction of the thickest myelinated fibres of the dorsal roots in undernourished rats.     

Inheritance of marker chromosomes from a cytogenetic survey of congenital heart disease

The inheritance of marker chromosomes was investigated in six families found during a survey of 250 cases of congenital heart disease. Distinctive morphological variation was seen in chromosomes 9, 16, 17 and members of the 13–15 group. It was thought that the variation occurred at sites of secondary constrictions and was due to inherited alteration in behaviour of these hetero-chromatic regions. In each family the marker chromosome was observed in two or more generations and was present in clinically normal relatives. They were similar to variants reported in the general population and were considered to be unrelated to congenital heart disease.