摘要:

Transfusion of blood products may be followed by viral hepatitis and aplastic anemia despite improved techniques for prevention. In view of the need for intensive therapy of hemophilia with blood products, the authors investigated the capacity of these concentrates to influence cultures of human bone marrow cells. Factor VIII concentrates contained a heat-stable dialyzable substance(s1 that drastically impaired59Fe incorporation in normal human bone marrow. Factor IX concentrates had less and cryoprecipitate had no such inhibitory activity. These studies may offer information regarding the effects of various blood products on bone marrow function.

ISSN:0002-9629    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The effect of acute and chronic expansion of the extracellular fluid volume on plasma renin concentration (PRC) was studied in normal Long-Evans rats (LE rats) and in rats with hereditary hypothalamic diabetes insipidus (DI rats). Chronic deoxycorticosterone acetate (DOCA) treatment, combined with a high sodium intake, significantly reduced PRC of both DI and LE rats, PRC of DI rats, however, remained higher than that of LE rats. Acute volume expansion, either alone or with DOCA treatment, also significantly diminished PRC of both DI and LE rats. PRC of untreated and DOCA-treated DI rats again remained significantly higher than that of LE rats after acute volume expansion. These findings suggest that the elevated PRC normally observed in DI rats is not due solely to diminished volume of extracellular fluid. Instead, the absence of ADH per se may directly alter renin secretion or the sensitivity of the granular cell to other stimuli.

ISSN:0002-9629    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Ventricular tachyarrhythmias are the leading cause of sudden cardiac death. Determination of the substrates conducive to the initiation of ventricular tachyarrhythmias remains an important clinical goal. The purpose of this study was to correlate electrophysiologic and histopathologic parameters conducive to the initiation of sustained ventricular tachycardia using programmed electrical stimulation in two canine models of myocardial infarction. Histopathologic correlates included: infarct pattern (heterogeneous vs. homogeneous morphology), distribution (viable epicardial or endocardial rim), and size. Twenty-one adult dogs were randomly divided into two groups: (1) 12 dogs underwent two-stage, 2-hour occlusion of the proximal left anterior descending coronary artery (LAD); and (2) nine animals had permanent, complete occlusion of the LAD with latex embolization. Using programmed ventricular pacing with two premature ventricular extrastimuli, initiation of ventricular tachycardia was attempted at both 1 and 2 weeks after infarction with the chest closed and opened each time. Electrophysiologic evaluation of the infarct type correlated significantly with the histologic morphology of the infarction (p < 0.001). the presence of a viable epicardial rim was an extremely important discriminating variable for ability to induce sustained ventricular tachycardia (p = 0.04). The presence of an endocardial rim was not significant (p = 1.0). Infarct size alone was only marginally related to ventricular tachycardia inducibility (p = 0.08). Non-uniform infarcts were more conducive to the initiation of sustained ventricular tachycardia than homogeneous infarcts (p = 0.025). The presence of a large, nonuniform infarct was the best overall discrimination variable for inducibility (p = 0.0002). Thus, in these experimental models, specific infarct morphologies correlate significantly with susceptibility to inducible sustained ventricular tachyarrhythmias.

ISSN:0002-9629    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The mechanical and electrical effects of hypoparathyroidism (Px), hypothyroidism (Tx), and hypothyroidism combined with hypoparathyroidism (TPx) were investigated by comparing simultaneously recorded transmembrane action potentials and isometric and isotonic contractions recorded from the myocardium. Left ventricular papillary muscles from male Wistar rats were studied electrically and mechanically in a muscle bath at 30oC, stimulated at 0.1 Hz and external calcium = 2.4 mM. No significant difference was found between control (C), Px, Tx, and TPx preparations with regard to resting tension and developed tension. However, time to peak tension, time to one half relaxation and time to peak shortening were significantly increased in preparations from animals that were Px, Tx, and TPx as compared with age-matched controls. Maximum velocities of shortening (Vs) and relengthening (Vr) at all relative loads studied were significantly depressed in Px preparations when compared with those of C muscles. A greater depression was found in the Tx muscle and still greater depression of these indices was noted in TPx muscles. No significant difference was found between C, Px, Tx, and TPx action potential with regard to resting membrane potential (RMP), action potential amplitude (AMP), overshoot (OS), or maximum rate of rise of the upstrock (Vmax). In contract, the duration of 50% (APD50) and 75% (APD75) of total repolarization to the RMP was significantly and consistently longer for Px Ap when compared with control, longer still in Tx muscles and longest in TPx muscles (11 ± 0.4 ms; 28 ± 1.4 ms vs. 13 ± 0.45 ms; 31 ± 1.2 ms vs. 16 ± 1.4 ms; 36 ± 1.6 ms vs. 58 ± 30.98 ms; 101 ± 4.8). These results sugeest that although pure hypothyroidism causes a depression in contractile and electrical parameters, it is the superimposed hypoparathyroidism that accounts for the marked prolongation in accounts for the marked prolongation duration. Thus, the parathytoid glands can be considered mechanical and electrical performance.

ISSN:0002-9629    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Protein catabolic rate (PCR) and protein balance were measured daily by computerized mass balance studies in 20 subjects during hospitalization after renal transplantation. All hospital courses were uncomplicated. Ten subjects received approximately 1 mg/kg/day prednisone, and ten subjects received 3–5 mg/kg/day prednisone on day 1 with a tapering dose to approximately 1 mg/kg/day by discharge. In both groups, PCR rose during the first 3–4 postoperative days then stabilized at an accelerated level. PCR was significantly greater in the higher prednisone group. Despite encouragement most subjects ate less protein than prescribed, and most were in negative protein balance. Mean daily and net protein deficits were more severe in the higher prednisone group. Higher protein intakes improved protein balance. The protein catabolic effects of the two regimens have been defined and a dose dependency demonstrated. In any therapeutic situation the use of the minimum effective dose of steroids seem advised, and high protein intake should be encouraged to improve protein balance. Some steroid morbidity might thus be avoided.

ISSN:0002-9629    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Carbohydrate intolerance is frequently seen in patients with hepatic cirrhosis. To study the role of the counter regulitory hormones, glucagon, cortisol and growth hormone in this disease, these hormones were measured in 11 patients with hepatic cirrhosis and six controls during a 4-hour oral glucose tolerance test (OGTT) and in five normal and cirrhotic subjects during steady-state plasma insulin and glucose concentrations (SSPGI) achieved with the euglycemic clamp technique. Fasting plasma glucose was 103 ± 4.3 mgldl in cirrhotics and 88 ± 3.3 mg/dl in controls (p <0.00l). Immunoreactive insulin (IRI) was 24.3 pU/ml in cirrhotics and 12.7 ± 2.2 pUlml in controls (p < 0.001); immunoreactive glucagon (IRG) was 263 f 30 pg/ml in cirrhotics and 122 ± 17.5 pg/ml in controls (p < 0.001); serum growth hormone (GH) was 4.4 ± 0.9 ng/ml in cirrhotics and 0.5 ± 0.1 ng/ml in controls (p < 0.001). During OGTT, the 2-hour glucose concentration was 201 ± 9.7 mgldl in cirrhotic subjects and 147 ± 10.0 mg/dl in controls (p < 0.001). IRG levels were suppressed by 20% of basal values in patients with cirrhosis, while controls showed 10% suppression after an oral glucose load. At 60 minutes, the serum GH was 14.7 ± 3.9 ng/ml in cirrhotics and 0.3 ± 0.1 nglml in controls (p < 0,001). The normal suppressive effect of hyperglycemia on GH secretion in controls was sharply contrasted by a paradoxical elevation of serum GH in the cirrhotic group. In the euglycemic clamp studies, plasma glucose and insulin were maintained at steady state concentrations that were almost identical in both groups. The amount of glucose metabolized (M) was 3.6 ± 0.4 mg/kg/min in cirrhosis and 6.8 ± 0.2 mg/kg/min in controls (p < 0.001). IRG levels during SSPGI were 99 ± 15 pg/ml in cirrhotics and 73 f 19 pg/ml in controls, and this difference was not statistically significant. There was no significant difference in the plasma cortisol concentrations in the two groups. GH, however, peaked at 18 ± 2.1 ng/ml in the cirrhotics during SSPGI, while it was only 1.6 ± 0.2 ng/ml in controls ( p < 0.001). It was concluded, therefore, that patients with hepatic cirrhosis have significant insulin resistance as shown by a reduction in the insulinmediated glucose utilization rates. The paradoxical elevations of serum GH concentrations may play a role in the insulin resistance and glucose intolerance of cirrhosis.

ISSN:0002-9629    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Human peripheral blood mononuclear cells (PBMC) were preincubated for 3 days in medium alone or with various mitogens then washed and irradiated. The preincubated cells then were culatured with autologous T-cells in an autologous mixed lymphocyte reaction (AMLR). Staphylococcal protein A (SPA) pretreatment of PBMC enhanced autologous Tlymphocyte proliferation from 1375 ± 321 cpm (mean ± SEM untreated PBMC) to 42,467 ± 7,985 cpm (SPA primed PBMC) (p < 0.01). The ability of SPA treated PBMC to enhance the AMLR was not simply a reflection of their proliferation in preculture, as PBMC precultured with phytohemagglutinin and concanavalin A showed greater proliferation than SPA-treated PBMC yet only minimally enhanced the AMLR. Kinetic studies and pre-exposure of PBMC to graded doses of gamma radiation showed that SPA augmentation of the AMLR was mediated by 2 components which differed in kinetics and radiosensitivity. Although incubation of PBMC with SPA did not increase the percentage of cells with detectable surface Ia antigen, SPA did increase the density of Ia in the preincubated cells. Cell separation studies revealed that SPA enhancement of the AMLR was not mediated by T-cells, but was mediated by a nonadherent non-E-rosetting fraction of cells. SPA enhancement of the AMLR was associated with an increased Ia density in the stimulator population but not with an increase in Ia positive cells and was mediated by proliferationdependent and proliferation-independent mechanisms.

ISSN:0002-9629    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Histologic bone changes of osteitis fibrosa and osteomalacia are commonly present in patients with end-stage renal disease. Although many patients are not symptomatic from these bone changes, some patients are severely disabled. Altered metabolism of vitamin D, calcium, phosphorus, and parathyroid hormone occurs in renal failure and contributes to the development of uremic bone disease. This article reviews the current theories of pathogenesis and treatment of renal osteodystrophy. In addition, the clinical presentation, pathogenesis, and treatment of the various aluminum-associated osteomalacic syndromes in uremia are discussed.

ISSN:0002-9629    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Essential thrombocytosis is a myeloproliferative disease not known to have consistent cytogenetic abnormalities. A 46-year-old black woman with essential thrombocytosis and a Philadelphia chromosome is reported. Iron deficiency and tuberculosis were present but when effectively treated did not result in resolution of thrombocytosis. Megakaryocytic hyperplasia of bone marrow, abnormal platelet function studies and a compatible clinical state suggested the diagnosis of essential thrombocytosis. The diagnostic criteria for other myeloproliferative diseases were not met. The Philadelphia chromosome was consistently obtained from bone marrow preparations. We conclude that the Philadelphia chromosome may be found in essential thrombocytosis as well as other, previously reported, myeloproliferative diseases.

ISSN:0002-9629    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Two patients with longstanding adrenal insufficiency developed severe mineralocorticoid deficiney during concomitant phenytoin treatment. A 64-year-old man with primary adrenal insufficiency of 41 years duration was treated with phenytoin for an acute seizure disorder. He subsequently developed mineralocorticoid insufficiency despite taking his customary dosages of cortisone acetate and fludrocortisone. This responded to volume repletion and increased fludrocortisone requirement from 0.05 mg to 0.4 mg daily, which decreased to the former amount following discontinuation of pheytoin. A 42-year-old woman with primary adrenal insufficiency of 3 years duration and a lifelong seizure disorder treated with phenytoin incurred multiple, life threatening episodes of mineralocorticoid insufficiency. Her fludrocortisone requirement was ultimately established as 2.0 mg daily with a normal hydrocortisone requirement and clearance rate. Fludrocortisone thus appears to be is sensitive to drugs that increse hepatic 6-beta-hydroxylation, such as phenytoin. Treatment with these inducing drugs may markedly alter mineralocorticoid requirements in patients with primary adrenal insufficiency.

ISSN:0002-9629    

出版商:OVID    

年代:1986

数据来源: OVID