DNA polymerase activity in the n.hexadecane-induced hyperkeratotic epidermis

DNA polymerase activity was determined in hyperkeratotic epidermis of the guinea pig by topical application of n.hexadecane. Epidermal cells were separated by Percoll gradient centrifugation. DNA polymerase alpha activity was higher in the basal cells, but polymerase beta activity was higher in granular cells than in cells from the other layers. The hyperkeratosis was accompanied by an increase in polymerase alpha activity in both the squamous and basal cells. However, polymerase beta activity decreased in the granular cells and was distributed almost uniformly across the epidermis. The distribution pattern of polymerase activities in the hyperkeratotic epidermis was not simply an enhancement of the pattern in normal epidermis.

New theory on the pathogenesis of acute myocardial infarction

Autopsy studies of hearts from 140 patients who had suffered acute myocardial infarction (AMI) and 26 cases of sudden coronary death revealed two distinct types of myocardial cell death: "kinetic cell death" (KD) and "static cell death" (SD). In KD, the predominant type of cell death in AMI-myofibrils disintegrated through alternating overcontraction and overextension. KD was found not only in patients having died after some time had elapsed from the onset of AMI, but also in cases of sudden coronary death. Muscle fibers in SD, which by contrast began to appear at least seven hours after the onset of AMI, characteristically preserved cross striations, while their nuclei were pyknotic or had already disappeared. Such fibers were observed only in territories peripheral to occlusive coronary thrombus, a secondary rather than a primary event that takes place during the course of AMI. As a result of the above observations, we were able to produce a new experimental model of AMI using mongrel dogs. As a preparatory procedure we first injected them intravenously with 2% calcium chloride at a constant rate for 90 or 120 minutes, and then with a sudden injection of caffeine, calcium chloride and catecholamine in order to induce KD. In contrast, ligation of the intraventricular coronary artery near its origin caused SD of myocardial fibers in the dependent territories. Overall results led us to conclude that AMI is initiated by instantaneous overcontraction of myocardial fibers, resulting in their KD, a phenomenon that could be called "myocardial self-destruction."

Hemagglutination with rhabdoviruses related to bovine ephemeral fever virus

Three different bovine ephemeral fever group viruses were tested for hemagglutination (HA). One of them, Tortilla Flat virus (CSIRO 368), agglutinated erythrocytes from geese, pigeons, horses, hamsters, mice and guinea-pigs when the concentrated infectious culture fluid was used as a hemagglutinin. The HA was dependent on the pH of phosphate buffered saline used as the erythrocyte diluent when using borate buffered saline (pH 9.0) with 0.4% bovine serum albumin as the antigen diluent. The optimal pH of the phosphate buffer was from 5.2 to 5.8. The HA, however, was not dependent on salt concentration. The incubation temperature did not affect the HA titer significantly. This HA reaction was inhibited by serotype specific antiserum.

Detection of bovine coronavirus in feces by reversed passive hemagglutination

A reversed passive hemagglutination (RPHA) method was developed for the detection of bovine coronavirus in fecal specimens. Sheep erythrocytes fixed with glutaraldehyde, and then treated with tannic acid were coated with anti-bovine coronavirus rabbit antibodies purified by affinity chromatography using bovine coronavirus linked to Sepharose 4B. The RPHA test was carried out by a microtiter method. Erythrocytes coated with purified specific antibodies were agglutinated by bovine coronavirus, but not by bovine rotavirus or enterovirus. The reaction was inhibited by antiserum to bovine coronavirus, confirming the specificity of the reaction. The RPHA test detected bovine coronavirus in 13 of 22 fecal specimens (59 per cent), from natural cases of diarrhea, while the positive rates were only 14 per cent (3/22) and 22 per cent (5/22) for immunofluorescent staining of primary cultures of calf kidney cells infected with the specimens, and immune electron microscopy respectively. The advantages of the RPHA method are its simplicity, high sensitivity and rapidity.

[Effect of infusion therapy on intrauterine fetal growth retardation (author's transl)]

It is requested for the control to the intrauterine fetal growth retardation (IUGR) to clarify the cause-and-effect relationship and to take the proper treatment under such a precondition. Following report covers the clinical report on the maternal infusion therapy mainly consisting of amino acids. 1) In the cases, to which the diagnosis of IUGR was given on basis of the development of symphisis-fundus length on the pregnogram and the fetal biparietal diameter (BPD), the occurrence of appropriate-for-gestational-age (AGA) is as extremely high as 44.5% when it is felt without treatment. In the abnormal patterns of symphisis-fundus length, consisting mainly of the threatened premature labor, the differential diagnosis is needed to the outward IUGR. 2) As the effect of the maternal infusion therapy mainly of amino acids on IUGR, given in addition to the oral nutrition, the increase of placental weight and fetal weight was observed at around NP-Cal/N of 99-116. No abnormality was observed in the maternal renal and liver function. 3) As the result of the maternal infusion therapy to 131 cases of IUGR, the occurrence ratio of the small-for-gestational-age (SGA) was 26.7%. No case of perinatal death or congenital malformation was observed.

Role of mediodorsal thalamic nucleus in olfactory discrimination learning in rats

Severe deficits in the acquisition of an olfactory learning-set task resulted from lesions of the central (olfactory) component of the mediodorsal thalamic nucleus but not from large lesions that destroyed olfactory projections to the amygdala. Complex olfactory learning may be mediated by the olfactory thalamocortical system and not by olfactory projections to the limbic system.

Control of the variability of the afferent discharge rate in frog muscle spindle by potassium blockers

Blockage of the K+ channels in the sensory terminal of frog muscle spindle by the combined application of BaCl2 and other K+ blockers makes it possible to reversibly change the sustained and irregular discharges into non-sustained regular discharges. As a similar change in the discharge pattern is also made by application of CoCl2 alone, though it is irreversible, the irregular and sustained discharge may be due to [Ca2+]i-activated potassium conductance.

Site of origin of calcium spike in frog muscle spindle

In order to define the site of origin of the calcium spike along the sensory nerve terminal of the frog muscle spindle, changes in the amplitude of the spikes during long-lasting polarizations of the nerve terminal were compared with those of full-sized and abortive spikes which occurred spontaneously. The amplitude of the calcium spikes superimposed on a spindle potential was not modifiable by application of polarizing currents of 6 nA or less, as well as that of the abortive spikes; while the amplitude of the full-sized spikes depended upon the polarizations. These results suggest that the calcium spikes may initiate along the non-myelinated filaments, as in the abortive spike, in contrast with the full-sized spikes to generate at the terminal node of the myelinated axon.

[Influence of active vitamine D3 on bones (author's transl)]

Influence of 1 alpha-OH-D3, an active vitamine D supplement, on bone cells was studied, histologically and electro-microscopically observing the vitamine D objective bone cell after treatment with the drug in a dose of 50 microgram/kg/day. Light-microscopic findings revealed that osteogenesis gradually became dominant after transient osteoporosis, leading to a disproportional state of the bone remodelling. In electromicroscopy, no morphological changes were observed, though the number of osteoclasts increased five days after treatment. Hypofunctional findings, however, appeared seven and ten days after treatment. On the other hand, findings of distinguishable osteogenesis, e.g. well-developed golgi complex (G), endoplasmic reticulum (ER), mitochondria (M), were observed in the osteoblast and osteocyte, defining the strong influence of vitamine D in a large dose on the osteoblast-osteocyte system. Especially, the osteoblast seemed to be influenced earlier and to a greater degree. We concluded that 1 alpha-OH-D3 in doses of 0.02 and 0.08 microgram/kg/day hardly caused any morphological changes in the bone cell in our experiment.