Endoscopy--Review

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Two-dimensional echocardiography in mitral annulus calcification

Mitral annular calcification, established by fluoroscopy, was studied by M-mode and two-dimensional echocardiography in 18 patients. M-mode echocardiography revealed the typical dense, linear echo of mitral annular calcification, but not its extent. Two-dimenstional echocardiography demonstrated a dense, elipsoidal echo at the junction of the left atrium and ventricle in the long axis view, and an area of calcification below the mitral valve in the short axis view. These patterns were not seen in 20 control patients without mitral annular calcification by fluoroscopy. Two-dimensional echocardiography establishes the site and extent of mitral annular calcification, minimizes the potential for diagnostic error associated with M-mode echocardiography, and is superior to M-mode echocardiography for the recognition of mitral annular calcification.

Hepatic necrosis in rats following halothane administration: protective effect of diethyldithiocarbamate

Foci of necrosis have been observed in the liver of 50% of enzyme-induced rats treated with halothane. The frequency of liver necrosis was significantly reduced by treatment with the free radical scavenger diethyldithiocarbamate. The severity of the lesion was not increased by repeated exposures to the anesthetic, and, although the frequency of liver necroses may be greater, the differences were not statistically significant.

The uptake of horseradish peroxidase by neuronal elements within the guinea-pig distal colon and its subsequent retrograde transport to the inferior mesenteric ganglion: an in vitro study using an intact neuronal system

An in vitro guinea-pig preparation comprising the inferior mesenteric ganglion (IMG), the colonic nerves, and a segment of the distal colon was used to study the uptake and retrograde transport of horseradish peroxidase by intact neurons. Peroxidase rapidly penetrated the colonic wall from the lumen and was taken into autonomic nerves by pinocytotic vesicles, usually of the coated variety. The peroxidase subsequently appeared in long vesicles within the axons, and, 24 hours later, could be detected in many neuronal perikarya throughout the IMG. The similarities between the modes of uptake of peroxidase by damaged and intact axons are discussed.

The uptake of horseradish peroxidase by damaged autonomic nerves in vitro

The uptake of horseradish peroxidase by damaged autonomic nerves was studied in vitro. Large amounts of the enzyme penetrated the axons in a diffuse (nonvesicular) form. This occurred within 90 minutes of application of the enzyme. Twenty four hours after application of the enzyme diffuse peroxidase was still present in the axoplasm, but it was 'diluted' as a result of great axonal swelling. Pinocytotic uptake of the enzyme was observed both 90 minutes and 24 hours after application of the enzyme. The swollen axons close to the point of ligation showed most evidence of pinocytotic uptake, largely into coated vesicles, and much membrane-bound peroxidase reaction product was present. The uptake of peroxidase in a membrane-bound form may be of particular significance for the subsequent retrograde transport of the enzyme.

Influences of physical conditioning and deconditioning on coronary vasculature of dogs

To investigate the effects of physical conditioning and deconditioning on the coronary vasculature, eight dogs were exercised by treadmill running. Five dogs were deconditioned by confinement in cages following the conditioning period. A technique was developed and validated for measuring circumflex coronary artery diameter from magnified projections of standardized coronary angiograms. Myocardial capillary density, perimeter, and basement membrane thickness were determined from electron microscopy of serial ventricular septal biopsy samples. Physical conditioning caused a small but statistically significant increase in cross-sectional area of the circumflex artery. Although physical conditioning caused no statistically significant changes in the myocardial capillaries, trends were apparent for increases in density and perimeter of myocardial capillaries and a decrease in basement membrane thickness. Physical deconditioning caused statistically significant reductions in cross-sectional area of the circumflex artery and in myocardial capillary density but little change in perimeter or basement membrane thickness of myocardial capillaries. The results suggest that physical conditioning may be associated with an improvement in coronary vascular capacity which may regress rapidly with deconditioning.

The role of calcium ions in the synthesis and transport of noradrenaline carrier vesicles in guinea-pig sympathetic neurons in vitro

Guinea-pig inferior mesenteric ganglia (IMG)/hypogastric nerve preparations were incubated in tissue culture media containing ethylene glycol-bis-(beta-aminoethyl ether)N,N'tetra-acetic acid (EGTA) or colchicine and examined either by fluorescence microscopy or by transmission electron microscopy. Two millimolar EGTA inhibited the accumulation of noradrenaline (NA) fluophore proximal to a crush, but did not produce an increase in the fluorescent intensity of, or the number of dense-cored vesicles (DCVs) within the neuronal perikarya. Calcium ions, but not magnesium ions, were able to block this effect of EGTA. Preparations incubated in the presence of colchicine (2.5 microgram/ml) showed a reduction in the amount of fluorescent material accumulating proximal to a crush, but an increase in both the fluorescent intensity and the number of DCVs within the neuronal perikarya. The suggestion that calcium ions are required for the synthesis of some part of the NA-containing vesicle rather than for their loading onto the axoplasmic transport mechanism is discussed.

The effects of hydrocephalus upon the developing brain. Histological and quantitative studies of the ependyma and subependyma in hydrocephalic rats

A suspension of kaolin was injected into the cisterna magna of 44 rats at 2 weeks of age. Animals killed at intervals from 5--19 weeks of age showed varying degrees of hydrocephalus. Light microscopy, scanning and transmission electron microscopy revealed stretching and flattening of the ependymal cells but no significant loss of cilia. Histological evidence of periventricular tissue damage in these chronically hydrocephalic animals was only present when the ventricular dilatation was extensive. A quantitative assessment was made of the ependymal and subependymal cell reactions around the lateral ventricles of the hydrocephalic animals. Although the ependymal cells were clearly stretched around the ventricles, there was no apparent proliferation of these cells. An increase in the total number of subependymal cells was observed in hydrocephalic animals when compared with a series of 39 aged-matched controls. The greatest proliferation was in the dorsal and lateral walls of the ventricles which were the regions most severely stretched by the ventricular dilatation. There is evidence that subependymal cells differentiate into astrocytes and microglia so that proliferation of these cells may be interpreted as a response to continuing and progressive brain damage in chronic hydrocephalus. Such progressive tissue damage could adversely affect the developing brain.

Fendosal and aspirin in postpartum uterine pain

The analgesic efficacy of fendosal, a new nonsteroidal anti-inflammatory agent structurally related to salicylic acid, was compared with that of aspirin and placebo in 100 patients with postpartum uterine pain in a single oral dose, parallel, stratified, randomized, double-blind design. With 650 mg aspirin and with 200 or 400 mg fendosal, but not with 100 mg, analgesic effects, as measured subjectively by mean pain intensity scores, began within 1 hr and had similar time-effect patterns for the first 4 or 5 hr. Thereafter with the 2 higher doses of fendosal analgesia contimued to increase, reaching a peak at 6 hr (p less than 0.05) and persisting beyond 7 hr (p less than 0.01), whereas there was no aspirin analgesia after the fifth hour. With 100 mg fendosal time of onset tended to be delayed 2 hr or more, and duration was short. The most effective treatment (largest mean 7-hr sum of pain intensity difference [SPID] scores) was 400 mg fendosal (p less than 0.01); 200 mg fendosal was rated second (p less than 0.01), 650 mg aspirin, third (p less than 0.05), 100 mg fendosal, fourth, and placebo, fifth. There was no significant side effects. These results demonstrate the efficacy of single doses of fendosal as well as the dose-dependent magnitude and time course of effects on postpartum uterine pain.

Buckthorn neuropathy: effects of intraneural injection of Karwinskia humboldtiana toxins

Ingestion of the endocarp of the coyotillo fruit, Karwinskia humboldtiana, a shrub of the buckthorn family, causes "Buckthorn neuropathy" in man and animals. Two neurotoxic compounds T496 and T544 were isolated from the endocarp and each toxin was dissolved in sesame oil and injected into the sciatic nerve of rats. The nerves were subsequently examined by teasing and as sections by light and electron microscopy. During the first 3--4 days after injection, oil droplets, probably containing toxin, were observed in the cytoplasm of Schwann cells with intact myelin sheaths. Clinical signs of weakness in the limb first appeared at 5--6 days and were accompanied by segmental demyelination mainly of the larger fibres. These observations suggest that the toxins have a primary action on Schwann cell metabolism. The results of local injection of purified toxins are discussed in relation to reports of nerve damage in animals following oral administration of the endocarp where intramyelin vacuole formation and segmental demyelination are prominent features.

Separation of erythropoietin responsive cells in fetal mouse liver

The erythropoietin responsive cells (ERC) in suspension cultures (ERCSC) of fetal mouse liver and the cells producing erythroid colonies in 2-day plasma clot cultures (CFU-E) sediment at similar rates. However, the sedimented fractions containing the majority of nucleated cells show minimal sensivitity to erythropoietin (Ep) and these cells sediment at a slower rate than the ERCSC. The studies suggest that in short-term suspension cultures of fetal mouse liver, Ep acts on morphologically unrecognizable cells to increase the number of hemoglobin-synthesizing cells rather than by increasing the quantity of hemoglobin synthesized per cell. This effect is similar to the principal in vivo action of Ep.

Comparisons of antidotal efficacy of sodium diethyldithiocarbamate, D-penicillamine and triethylenetetramine upon acute toxicity of nickel carbonyl in rats

Sodium diethyldithiocarbamate, D-penicillamine, and triethylene-tetramine were administered to rats by im injection in dosages equivalent to 0.6 times their respective LD50 values in order to compare their relative effectiveness in prevention of death caused by exposure for 15 min to inhalation of nickel carbonyl (1.4 or 4.2 mg Ni (CO)4/liter of air). When the three drugs were administered to groups of rats at 10 min before or after the exposure to nickel carbonyl, sodium diethyldithiocarbamate was the most effective antidote. In contrast, then the drugs were administered at 6 hr after exposure to nickel carbonyl, D-penicillamine was the most effective antidote. Based upon the combined results of 4 sets of experiments, sodium diethyldithiocarbamate and D-penicillamine were significantly more effective than triethylenetetramine. The authors recommend that sodium diethyldithio-carbamate should remain the chelating agent of choice for therapy of nickel carbonyl poisoning. If sodium diethyldithiocarbamate is not available or if its use is contraindicated, D-penicillamine might be considered as an alternative chelating agent.

beta-O-thalassemia from Algeria: genetic and molecular characterization

beta-Thalassemia is a major public health problem in Algeria. During a survey, a family including two cases of betaO-thalassemia was studied. The family study indicated that two of the affected siblings had homozygous beta-thalassemia; there were also both normal and heterozygous siblings, and both parents had beta-thalassemia trait. In the two cases of betaO-thalassemia there was no hemoglobin A in the peripheral blood, and no beta-globin chain synthesis in whole cell incubations. Hybridization of purified complementary DNA specific for alpha- and beta-globin messenger RNAs demonstrated less than 1% mRNAbeta relative to mRNAalpha in circulating reticulocytes, and for one case in total RNA from bone marrow. There is no apparent beta-globin gene deletion as determined by hybridization in globin cDNAbeta sequence excess. Therefore the Algerian cases studied are similar in molecular pathology to some Southern Italian and Asian cases described previously, and differ from other Italian and Chinese betaO-thalassemias, in which hybridizable mRNAbeta has been demonstrated, and from deltabetaO-thalassemia, which is caused by a gene deletion.