The biochemical components, enzymes, and other items from the sera and plasma of normal male and female Göttingen miniature pigs from 3 to 20 months of age were investigated. The data were compared with the normal biochemical values of rhesus monkeys, beagle dogs, and JCL: SD rats. The following characteristics were noted. 1. Activities of serum enzymes were higher and their normal ranges wider than in the other experimental animal sera. 2. Of lipid components measured, total cholesterol and phospholipid showed strikingly lower values than in the monkey and the dog. 3. The serum urea nitrogen levels were lower than in the other experimental animal sera. 4. Serum creatinine and potassium were present at relatively high levels, with wide normal ranges. 5. There was a tendency with advancing age toward lower alkaline phosphatase and higher total protein and creatinine. 6. Leucine aminopeptidase was higher while total cholesterol and phospholipid were lower, in the male than in the female. 7. The electrophoretic patterns of serum protein and lipoprotein differed markedly among the species.

Animals↗

PubMed1980

Peripheral nervous system functions of workers exposed to n-hexane at a low level.

In order to assess the effects on the peripheral nervous system of n-hexane at a low level, an epidemiological study using a questionnaire, neurological examinations, and neurophysiological studies was carried out on two age-matched groups; one, consisting of 14 exposed workers and the other, of 14 control workers. The 8 h time weighted average of n-hexane concentration in the exposure environment was 58 +/- 41 (mean +/- SD) ppm. In the individual worker, no obvious signs could be found indicating damage to the nervous system that were referable to the n-hexane exposure. On the other hand, when the subjects were taken in groups, the results obtained from the exposed group showed a minor partiality for functional impairment of the peripheral nervous system in many test items. In particular, statistically significant differences between the two groups were detected in the following items: (1) inquiries by questionnaire for persistent or transient symptoms regarding muscle weaknesses and dyesthesia of limbs; (2) the jump test on one foot; (3) the tuning fork test for vibration sensation on the radial processes; (4) the maximal velocity and the residual latency of motor nerve conduction of the posterior tibial nerve. In conclusion, it is not likely that at exposure levels less than the current threshold limit value of 100 ppm proposed by ACGIH, n-hexane may induce clinically overt polyneurophathy. However, there is no gainsaying the possibility that in the exposed workers as a whole, small cumulative effects in the peripheral nervous system may be brought about by long-term n-hexane exposure less than 100 ppm.

Adult↗

PubMed1980

Pathophysiological significance of coronary collaterals for preservation of the myocardium during coronary occlusion and reperfusion in anaesthetised dogs.

The significance of pre-existing coronary collaterals for preservation of the myocardium during coronary occlusion and reperfusion was studied in anaesthetised open-chest dogs. The extent of myocardial ischaemic damage was assessed by the accumulation of calcium in the central zone of the ischaemic area and the size of myocardial infarct by the p-nitroblue tetrazolium staining method. Myocardial creatine kinase release was considered as an index reflecting both the extent of ischaemic myocardial damage and the size of the infarct. Reperfusion with the arterial blood of a main branch of the left coronary artery following the 60 min occlusion aggravated the ischaemic myocardial damage, as evidenced by exaggerated cardiac irregularity, myocardial calcium accumulation, and creatine kinase release. The myocardial calcium content and the logarithm of the creatine kinase release during reperfusion were linearly related to the infarct size. These parameters of myocardial damage were inversely related to the retrograde blood flow through the peripheral end of the occluded artery or the ratio of the retrograde-to-orthograde flow, indicating that the pre-existing collaterals influence preservation of the ischaemic myocardium. Thus, it is suggested that the collateral flow available during an ischaemic episode determines the viability of the myocardial cells during ischaemia, and in turn during reperfusion.

Animals↗

PubMed1980

Ca2+ regulation in vascular smooth muscle. II. Ca2+ binding of aorta leiotonin.

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Actins↗

PubMed1980

Does activation of cyclic AMP dependent phosphorylation induced by beta-adrenergic agent control the tone of vascular muscle?

1. The relaxing action of the beta-adrenergic agent, isoprenaline, on the porcine coronary artery was investigated in relation to the cyclic AMP level, the endogenous binding of cyclic AMP to the regulatory unit of cyclic AMP dependent protein kinase or the phosphorylation as a result of activation of protein kinase of the muscle homogenate in Krebs solution and excess [K]o solution. These relations were also compared with those of the rat cardiac muscle, in which isoprenaline showed a positive inotropic action. 2. Excess [K]o decreased the cyclic AMP level in proportion to the amplitude of K-induced contracture in the porcine coronary artery. Isoprenaline increased the cyclic AMP level in Krebs solution, while it had no effect in excess [K]o. 3. In the porcine coronary artery, the particulate fraction possessed only 5% of the total cyclic AMP dependent protein kinase, while in the rat cardiac muscle, the particulate fraction was 25% of the total protein kinase. 4. The cyclic AMP dependent protein kinase in the particulate fraction of the porcine coronary artery was already saturated with the endogenous cyclic AMP. However, the binding of cyclic AMP to the protein kinase in the particulate fraction in the cardiac muscle and in the cytosol fraction of both tissues were increased in accordance with the cyclic AMP level. In the coronary artery, the protein kinase in the cytosol fraction was bound to a greater extent with cyclic AMP than was measured in the rat cardiac muscle. 5. In the rat cardiac muscle, isoprenaline enhanced the phosphorylation, detected by autoradiography of SDS gel electrophoresis in individual fractions of phosphorylated protein, while little enhancement was observed in the porcine coronary artery. 6. These observations led to the conclusion that in the porcine coronary artery, beta-adrenergic agent increases the levels of cyclic AMP but does not increase the phosphorylation. If the phosphorylation catalysed by cyclic AMP dependent protein kinase was utilized for Ca mobilization in the cell, the change in the cyclic AMP level would probably not have a causal relation to the muscle tone. This conclusion, however, may not be applicable in the case of the cardiac muscle.

Animals↗

PubMed1980