Lesions in the rat soleus muscle following eccentrically biased exercise.

Morphological changes in skeletal muscle related to lengthening (eccentric) contractions have been noted by several laboratories. However, a systematic examination of skeletal muscle following repetitive eccentric contractions is lacking. This study was undertaken to study lesions and determine their relative densities in rat soleus muscle 30 min following level or downhill treadmill exercise.

Sympathetic neural influences on muscle blood flow in rats during submaximal exercise.

These experiments were designed to estimate the involvement of the sympathetic innervation in regulation of hindlimb muscle blood flow distribution among and within muscles during submaximal locomotory exercise in rats. Blood flows to 32 hindlimb muscles and 13 other selected tissues were measured using the radiolabeled microsphere technique, before exercise and at 0.5, 2, 5, and 15 min of treadmill exercise at 15 m/min.

The effect of allopurinol and catalase on cardiovascular hemodynamics during hemorrhagic shock.

The primary objective of this study was to determine the effect that the xanthine oxidase inhibitor allopurinol (ALLO) and the hydrogen peroxide scavenger catalase (CAT) have on the cardiovascular compensatory ability of the dog to respond to severe hemorrhagic hypotension. Twenty-four mongrel dogs were anesthetized with sodium pentabarbitol and surgically prepared to monitor 1) average arterial blood pressure (AAP), 2) central venous pressure (CVP), 3) heart rate (HR), 4) cardiac index (CI = CO/kg), and hindlimb skeletal muscle blood flow (MBF). Total body vascular conductance (TBC) and skeletal muscle vascular conductance (MVC) were calculated by dividing the CI or MBF by the difference between the AAP and CVP.

Are opioid receptors involved in the bradycardiac and hypotensive action of clonidine?

Experimental evidence that supports or rejects an involvement of opioid receptors in the cardiovascular effects of clonidine was sought. In anesthetized rabbits, clonidine decreased blood pressure and heart rate. These effects were related to the clonidine dose.

Separation of three compositionally distinct subclasses of rat high density lipoproteins by heparin-affinity chromatography.

The composition of 3 subclasses of plasma high density lipoproteins (HDL) separated by heparin-affinity chromatography was characterized. Plasma was obtained from Fischer-344 adult male rats fed a semi-purified diet containing 1% cholesterol. HDL particles were isolated by ultracentrifugation and agarose column chromatography.

Preferential alkylation by 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) of guanines with guanines as neighboring bases in DNA.

The base sequence of DNA has been shown to influence the kinds and amounts of alkylation of purine bases by N-methyl-N-nitrosourea [W. T. Briscoe and L-E.

Polyunsaturated fatty acids alter sterol transbilayer domains in LM fibroblast plasma membrane.

Sterols are asymmetrically distributed between the leaflets of animal cell plasma membranes. Although transbilayer migration of sterols is extremely rapid, s to min, previous experimental manipulations have not altered their transmembrane steady-state distribution. However, the effect of polyunsaturated fatty acids has not been reported.

Melittin-evoked increase in plasma corticosterone levels.

The present study was undertaken to systematically evaluate the effect of melittin on nonstress pituitary-adrenal function of the adult female rat. In the first study rats were given melittin (0.5 mg.

Renal glutathione homeostasis in compensatory renal growth.

Glutathione homeostasis was investigated in unilaterally nephrectomized and sham-operated rats. Following twelve days of compensatory renal growth, it was found that the concentrations of glutathione and glutathione disulfide in representative samples of the entire remnant right kidney from the nephrectomized rats were similar to those found in corresponding samples of the right kidneys from the sham-operated rats. However, since the mass of the remnant right kidneys in the nephrectomized rats was greater than that of the right kidneys from the sham-operated rats, the absolute content of glutathione and glutathione disulfide was greater in the remnant right kidneys of the nephrectomized rats than in the right kidneys of the sham-operated rats.

Effects of extended feeding of decocainized erythroxylon coca leaves on growth and selected organs in rats and rabbits.

Erythroxylon coca leaves from the Trujillo area of Peru were extracted with methylene chloride to remove most cocaine-like alkaloids. The decocainized leaves were formulated in a honey-water vehicle and fed on a chronic basis to female rats for 32 weeks and female rabbits for 13 weeks. Rabbits fed decocainized leaves at doses of 21 or 210 mg demonstrated no significant change in growth (weight gain) when compared with those receiving vehicle.

Compositional changes in plasma high-density lipoprotein particles in marginally zinc-deficient male rats.

This study investigated the effect of zinc status on the lipid and apolipoprotein composition of high-density lipoproteins (HDL) in adult male rats fed a semipurified diet containing a marginal level (2.8 mg/kg) of Zn as compared with the pair-fed and ad libitum-fed controls given an adequate level (30.8 mg/kg) of Zn for 7-10 wk.

Pseudocoarctation of the aorta.

We report a case of a 50-year-old man with pseudocoarctation of the aorta that we examined with magnetic resonance imaging (MRI) and digital subtraction angiography (DSA). The MR images demonstrated the characteristic "kink" of the aorta and the absence of true coarctation. These appearances were confirmed by DSA, but we believe MRI to be the better method for examining the aorta because it is non-invasive and has the ability to display the mediastinal anatomy in the sagittal plane, in addition to the axial and coronal planes.

The role of iron in the growth and hemolysin (Streptolysin S) production in Streptococcus pyogenes.

Four strains of Streptococcus pyogenes were propagated at 37 degrees C in a reduced iron medium supplemented with Fe3+-citrate to give concentrations of 1 through 11 micrograms per milliliter, in order to observe the effects of iron on growth and on the vitro production of Streptolysin S. Both growth and hemolysin production were observed to be influenced by medium iron concentration of which 1.2 micrograms per ml of iron was critical.

Quantitative inter-strain comparison of the distribution of choline acetyltransferase activity in the rat cochlear nucleus.

The distribution of choline acetyltransferase activity in the cochlear nucleus of Sprague-Dawley albino rats was quantitatively compared to those in two strains of pigmented rats, Long Evans hooded and Brown Norway, using microdissection and radiometric assay techniques. Although activities tended to be, on the whole, higher in the albino rats, the differences were fairly minor. The relative distributions of choline acetyltransferase activity were generally similar among the 3 rat strains, not only among regions, but also within regions.

Effect of marginal zinc deficiency on the apolipoprotein-B content and size of mesenteric lymph chylomicrons in adult rats.

To investigate the mechanisms underlining the impaired intestinal absorption of lipids in zinc deficiency, the apo-B content and chemical composition of chylomicrons from marginally zinc-deficient rats fed 2.8 ppm of dietary zinc (ZD) were compared with those from pair-fed (PF) and ad libitum control (CT) groups fed an adequate level (30.8 ppm) of zinc.

New method for formulation of amino acid concentrations and ratios in diets of rats.

Parameters derived from the application of the saturation kinetics model (SKM) to rat growth experiments were used to formulate a complete dietary amino acid mix for weanling rats. Dietary ratios and concentrations for indispensable amino acids (IAA) and arginine were calculated using the parameter K0.5.

Differential plasma corticosterone responses to electrical stimulation of the medial and lateral septal nuclei.

To pursue the possibility that subdivisions within the medial and lateral septal nuclei are differentially involved in adrenocortical function, plasma samples obtained prior to and following electrical stimulation of the septal nuclei of urethane (1.30 g/kg)-anesthetized female rats were assessed for corticosterone concentration. Hippocampal EEG, ECG, heart rate (HR), mean arterial pressure (MAP) and respiration were routinely monitored, and timed blood samples (0.

Psychoneuroimmunology, new approaches to neurobehavioral testing.

A review of the literature in the field of psychoneuroimmunology was reported by Robert Ader [1]. Basically, three research approaches have been used to demonstrate a relationship between central sites within the brain that have modulatory influences on the immune system. These include: (1) both the electrical stimulation and surgical lesioning of nuclei in the hypothalamus; (2) traditional behavioral conditioning; and (3) behavioral stress studies.

Muscle blood flow and fiber activity in partially curarized rats during exercise.

We previously reported that low doses of d-tubocurarine attenuated glycogen loss in red muscles of rats during treadmill walking but that the initial hyperemia in the muscles was normal. The present studies were performed to 1) determine with electromyography (EMG) whether red muscle fiber activity is reduced in walking, curarized rats and 2) study muscle blood flow and glycogen loss during running with different doses of curare (dose response). At 0.

The study of the effect of human chorionic gonadotrophic (HCG) hormone on the survival of adrenal medulla transplant in brain. Preliminary study.

Autologous adrenal cortex was completely dissected off the medulla using microdissection. The adrenal medulla tissue was transplanted to the lateral ventricle in twenty-one adult rats. Group A consisting of ten animals received 200 units of HCG per 100 gram body weight daily for one week and then on every alternate day for seven weeks.

Effects of trapezoid body and superior olive lesions on choline acetyltransferase activity in the rat cochlear nucleus.

Using a microdissection and quantitative microassay approach, choline acetyltransferase activities were mapped in the cochlear nuclei of rats having either transection of the trapezoid body or destruction of the superior olivary complex on one side in the brain stem. Lateral trapezoid body transection resulted in dramatic loss of choline acetyltransferase activity in all parts of the ipsilateral cochlear nucleus, while more medial transection had little effect. Destruction of the superior olivary complex resulted in dramatic loss of choline acetyltransferase activity in the ipsilateral cochlear nucleus, and detectable loss also contralaterally.

Effect of olivocochlear bundle transection on choline acetyltransferase activity in the rat cochlear nucleus.

Using a microdissection and quantitative microassay approach, choline acetyltransferase activities were mapped in the cochlear nuclei of rats having complete transections of the olivocochlear bundle on one side in the brain stem. In rats in which the trapezoid body was not significantly damaged by the lesion, consistent reductions of choline acetyltransferase activity in subregions of the lesion-side cochlear nucleus, as compared to the control side, averaged about 20%. Nevertheless, a profound lesion-side reduction of choline acetyltransferase activity was found in a branch connection from the olivocochlear bundle to the cochlear nucleus.