Showing papers by "Veterans Health Administration published in 1970"

On the mechanism of platelet function inhibition by acetylsalicylic acid.

Abstract: SummaryAspirin produces alteration of platelet function characterized by loss of secondary aggregation in response to ADP or epinephrine, and inhibition of aggregation by collagen. In addition, platelet factor 3 release by these reagents is reduced. A similar platelet lesion was produced by an acetylating agent, acetic anhydride, supporting earlier concepts that aspirin activity against platelets may be a consequence of acetylation. An attempt to identify specific acetylation of platelets with acetyl-1-14C salicylic acid was unsuccessful. Although platelet uptake of the label was demonstrated, metabolic incorporation of acetate could not be excluded.

Purification of hypothalamic releasing hormones of human origin.

Abstract: Acetic acid extracts of 339 defatted human hypothalami were subjected to a precipitation procedure and then to separation by several successive steps in order to purify and characterize human releasing hormones.1 Growth hormone-releasing hormone (GH-RH) and FSHreleasing hormone (FSH-RH) were measured by stimulation of release of GH and FSH, respectively, from rat pituitaries in vitro. LH-releasing hormone (LH-RH) and thyrotropin-releasing hormone (TRH) were followed by in vivo assays. The TSH, GH, FSH and LH released were measured by bioassays. LH and FSH were also measured by radioimmunoassays. Gel filtration on Sephadex G-25 separated GH-RH from TRH, LH-RH and FSH-RH. GH-RH was further purified by free-flow electrophoresis and chromatography on carboxymethylcellulose (CMC). TRH, LH-RH and FSH-RH were concentrated by phenol extraction and then chromatographed on CMC, which separated TRH from LH-RH and FSH-RH. In the systems described, as well as others, the behavior of human hypothalamic releasi...

Intravenous hyperosmolar alimentation.

Abstract: The value of nutrition in surgery has been well appreciated for the past two decades. Although it has become increasingly obvious that protein metabolism often plays a decisive role in the final outcome of patients who have undergone surgery, it has rarely been possible to obtain a state of positive nitrogen balance following major surgical procedures. Since many investigators have shown that it takes approximately 150 nonprotein calories to spare 1 gm of nitrogen, it was thought impossible to obtain positive nitrogen balance by parenteral routes because of the hypertonic solution required. Recently, Dudrick et al1-3raised six Beagle puppies to full growth, utilizing only intravenous alimentation. High doses of carbohydrate and protein hydrolysate were infused to supply adequate calories and protein factors. Subsequently, Dudrick et al have supported many patients having serious chronic gastrointestinal disease with intravenous alimentation and have established a positive nitrogen balance in each.4-7

Failure of putrescine and other polyamines to promote FSH release in vitro.

Abstract: Low concentrations of the polyamines putrescine (0.01–0.2 μg/ml medium), cadaverine (0.2 μg/ml), spermine (1.0 μg/ml), spermidine (1.0 μg/ml) and agmatine (1.5 μg/ml) did not enhance the release of FSH from anterior pituitaries of male rats incubated in vitro. All the polyamines tested were equally ineffective when incubated with pituitaries in the presence of hypothalamic tissue. In contrast, highly purified porcine FSH-releasing hormone1 (FSH-RH) in doses as low as 0.001–0.003 μg/ml medium significantly stimulated FSH release by pituitaries from normal intact male rats, ovariectomized rats pretreated with estrogen and progesterone, and castrated rats pretreated with testosterone propionate. These in vitro methods can be used successfully to detect FSH-RH activity in various stages in the purification of the extracts. The results clearly demonstrate that the polyamine substances tested do not represent the primary physiological FSH-RH.1 (Endocrinology 86: 903, 1970)

Chronic hydronephrosis: observations on the mechanism of the defect in urine concentration.

Abstract: SummaryThe renal concentrating and diluting mechanism was examined in dogs with unilateral chronic hydronephrosis and compared to the contralateral normal side. Urine concentrating ability and concentrating capacity were markedly impaired in the chronically hydronephrotic kidney. However, as previously reported, fractional free water clearance over a large range of distal delivery was identical in both kidneys. Significant reductions in papillary and medullary nonurea solute concentration were present in the hydronephrotic kidneys as compared to controls during both hydropenia and hydration.It is postulated that reduction in the number of functioning nephrons in the medulla results in a decrease in sodium transport into the interstitium and, therefore, in reduced medullary hyper tonicity. This, by decreasing free water back diffusion out of the collecting duct, would result in the impaired urinary concentrating ability and capacity observed in chronic hydronephrosis.

Hereditary nephritis in the Negro. Report of a kindred.

Abstract: A Negro kindred which demonstrated an unusual racial incidence of hereditary nephritis, also exhibited a number of other relatively uncommon features. Three members of the kindred had cataracts; all three had nephritis, one died of renal failure, and two had deafness. Two members, 15 and 16 years old, had large urinary excretion of protein satisfying the criteria of the nephrotic syndrome, and both had eighth nerve involvement. A 17-year-old girl died of renal failure, and a 4-month-old boy has an abnormal urine sediment.

Pulmonary complications following liver trauma.

Abstract: : Progressive pulmonary insufficiency has been observed clinically in two patients after hepatic trauma and was associated temporally with the manipulation of the organ necessary for operative repair. In dogs subjected to a standardized liver contusion, depression of pulmonary mechanics, arterial PO2, and surfactant were observed after infusions of simple extracts of hepatic tissue or bile. No damage was noted after hepatic injury alone. Light and electron microscopy showed edema, hemorrhage, and destruction of capillary endothelium in both groups although more alveolar cell damage was noted after liver extract infusion suggesting an additional toxin. Many factors may operate to facilitate lung damage, and the vulnerability of the lung to liver products suggests increased attention to ventilatory support following repair of hepatic injuries. Survival of one clinical case was facilitated by the use of an expiratory resistor in association with positive-pressure ventilation. (Author)