Cardiac pathology associated with high sustained +Gz: I. Subendocardial hemorrhage

Adult miniature swine were exposed to various levels and durations of +Gz. After exposure, all swine were euthanized and necropsied. Gross, histologic, and electronmicroscopic observations were made on the heart tissue. Subendocaridal hemorrhage (SEH) was commonly found in the left ventricle, rarely in the right ventricle, and its severity was directly related to : a) level and duration of G exposure, b) heart rate, and c) catecholamine activity. SEH was made more severe with i.v. atropine 4 mg, and prevented with i.v. propranolol 20 mg. Heart hemorrhage was usually limited to the immediate subendocardial region and frequently surrounded Purkinje's fibers. In severe cases, however, hemorrhages penetrated several millimeters into the heart muscle and sometimes penetrated Purkinje's fibers. Restraint of unanesthetized swine in the centrifuge couch, low G-levels, and/or i.v. injections of atropine or epinephrine produced minimal SEH lesions.     

Hospital staffing and hospital costs

A comparative study of costs per bed per day in teaching hospitals affiliated with Monash University compared with large non-teaching metropolitan hospitals (1964 to 1974) shows they are much higher in teaching hospitals. There is no evidence that this is due to the additional costs arising from the clinical schools. Research in the teaching hospitals and the accompanying high professional standards and demands on services are major factors accounting for the difference. Over the decade studied, the resident staff have increased by 77% and other salaried staff by 24%. The index of expenditure for the three teaching hospitals in the decade has increased by 386%.     

Microviscosity of togavirus membranes studied by fluorescence depolarization: influence of envelope proteins and the host cell

The microviscosities of the hydrophobic regions of the membranes of intact Semliki forest and Sindbis viruses grown on BHK-21 cells, of liposomes derived from the extracted viral lipids, and of protease-treated virions were measured by fluorescence depolorization using the fluorescence probe 1, 6-diphenyl-1,3,5-hexatriene. The intact virus membranes were found to have a higher microviscosity than did virus-derived liposomes, indicating the viral envelope proteins contribute to microviscosity. However, protease-treated virus, devoid of protruding spikes but with residual lipophilic peptide tails, was found to have a microviscosity more similar to that of the intact virus than to that of protein-free liposomes. Sindbis virus grown in BHK-21 cells at 37 C had a much higher microviscosity than did Sindbis virus grown on Aedes albopicuts cells at 22 C. Sindbis virus grwon in A. albopictus and BHK-21 cells also gave higher microviscosity values than did the intact host cells. These data indicate that both the virion proteins and the cellular lipids selected during viral growth and maturation contribute to the increased microviscosity of togavirus membranes.     

Treatement of excessive weight gain in patients taking lithium

Six female primary affective disorder patients who had gained an average of 9.5 kg while taking lithium lost an average of 2.9 kg on a 10-day 900 calorie a day hospital diet containing 100 mEq of sodium per day. No evidence of lithium toxicity was observed on this regimen. There was no evidence that fluid retention played a major role in the weight gain.     

Gelatinisation Characteristics and Enzyme Susceptibility of Different Types of Barley Starch in the Temperature Range 48–72°C1

The gelatinisation temperatures, pasting characteristics and enzymic susceptibilities in the temperature range 48–72°C of normal, high amylose, low amylose and zero amylose barley starches were determined. Normal starches had the lowest gelatinisation temperatures, but low and zero amylose starches had the lowest pasting temperatures. Normal starches were the most readily soluble in water at 48–60°C in the presence of a mixture of α‐amylase, β‐amylase and limit dextrinase and were most readily broken down to reducing sugars by these enzymes. High amylose starch was the most resistant to enzymic hydrolysis in the temperature range 48–72°C and, hence, produced the lowest level of reducing sugars.     

Relationships Between Structure and Activity in the α-Amylase Family of Starch-metabolising Enzymes

α-Amylases are known to be multidomain proteins, i.e., the molecules consist of several folding units. Each α-amylase is believed, however, to have a catalytic domain consisting, of a barrel of eight parallel α-strands surrounded by eight α-strands. with an extra helix inserted after the sixth γ-strands. The α-strands and helices alternate along the polypeptide chain and are linked together by irregular loops. Amino acid residues situated on the loops joining the C-terminal end of each α-strand to the N-terminal end of the following helix make up the active site of the enzymes. A similar structure has been found in cyclodextrin glucanotransfcrases and it is now believed that such a (α/α)8-barrel also constitutes the catalytic domain of enzymes active on α-1.6-glucosidic bonds, and of enzymes with dual specificity for both α-1.4- and α-1.6- bonds. Knowledge of the three-dimensional structure of α-amylases and cyclodextrin glucanotransferase has made possible identification of structural features important for enzymic activity and specificity. By analogy, some general conclusions are reached concerning pullulanase, isoamylase. oligo-1,6-glucosidase, neopullulanase and branching enzymes.     

Localization of dopamine1A receptor mRNA in different vascular beds in rat: a nonradioactive in situ hybridization study

In situ hybridization of a biotin-labeled specific dopamine1A (D1A) receptor gene oligonucleotide probe combined with computer-assisted image analyzer was used to directly visualize D1A receptor mRNA and quantify the relative mRNA levels in sections of rat aorta and pulmonary and caudal arteries. Positive D1A receptor mRNA signals were found in rat aorta and pulmonary arteries, while no specific signals could be detected in the caudal artery. D1A receptor mRNA was located mainly within the medial layer of aorta, with intimal distribution in the pulmonary artery. The density of D1A receptor mRNA in different vascular beds demonstrated heterogeneity. D1A receptor mRNA levels in the aorta were much higher than those in the pulmonary artery (p < 0.01). These results demonstrate the existence of D1A receptor mRNA in both aorta and pulmonary beds, although with different distribution and density. The results further support the heterogeneity of the D1A receptor in different vascular beds.     

Calibrating the UHF technique of partial discharge detection usinga PD simulator

The paper describes a technique for simulating the presence of partial discharges in gas-insulated substation (GIS) equipment. The technique employs a pulse generator to inject current pulses through a suitable protrusion. The current pulses have similar temporal characteristics to those produced by an actual discharge event, with the added advantage that their magnitudes can be controlled accurately. Because the pulses are highly reproducible, they are ideally suited for investigating the UHF technique of partial discharge detection. The paper discusses the relationship between the magnitude of the UHF signal received by a coupler and the discharge magnitude. It also shows that the coupler signal is dependent on the protrusion length and on the spatial relationship between the protrusion and the coupler. The implications for practical discharge measurements in GIS also are discussed     

No effect of creatine supplementation on oxidative stress and cardiovascular parameters in spontaneously hypertensive rats

Background

Exacerbated oxidative stress is thought to be a mediator of arterial hypertension. It has been postulated that creatine (Cr) could act as an antioxidant agent preventing increased oxidative stress. The aim of this study was to investigate the effects of nine weeks of Cr or placebo supplementation on oxidative stress and cardiovascular parameters in spontaneously hypertensive rats (SHR).

Findings

Lipid hydroperoxidation, one important oxidative stress marker, remained unchanged in the coronary artery (Cr: 12.6 ± 1.5 vs. Pl: 12.2 ± 1.7 nmol·mg^-1; p = 0.87), heart (Cr: 11.5 ± 1.8 vs. Pl: 14.6 ± 1.1 nmol·mg^-1; p = 0.15), plasma (Cr: 67.7 ± 9.1 vs. Pl: 56.0 ± 3.2 nmol·mg^-1; p = 0.19), plantaris (Cr: 10.0 ± 0.8 vs. Pl: 9.0 ± 0.8 nmol·mg^-1; p = 0.40), and EDL muscle (Cr: 14.9 ± 1.4 vs. Pl: 17.2 ± 1.5 nmol·mg^-1; p = 0.30). Additionally, Cr supplementation affected neither arterial blood pressure nor heart structure in SHR (p > 0.05).

Conclusions

Using a well-known experimental model of systemic arterial hypertension, this study did not confirm the possible therapeutic effects of Cr supplementation on oxidative stress and cardiovascular dysfunction associated with arterial hypertension.