摘要:

Molecular mechanisms regulating the cardiac hypertrophic response to increased hemodynamic load are understood poorly. Insulin-like growth factor I (IGF I) is a mitogen that is thought to play a key role in pre- and postnatal growth. To investigate a possible role of IGF I in the cardiac response to pressure overload, rats underwent banding of the ascending aorta immediately above the aortic valve using a hemoclip, or a sham procedure. An analysis of left-ventricular RNA by Northern hybridization using a32P-labeled IGF I cDNA revealed four messenger ribonucleic acid transcripts of 7.6, 4.6, 1.7, and 0.9 to 1.2 Kb. Insulin-like growth factor I messenger ribonucleic acid was quantitated by ribonuclease protection assays using a rat exon 3 riboprobe. There was a sustained increase in IGF I mRNA levels that correlated temporally with the development of left ventricular hypertrophy. These results indicate that left ventricular pressure overload is associated with an induction of cardiac IGF I gene expression. Insulin-like growth factor I may play a role in the response to increases in wall stress and likely contribute to cardiac hypertrophy.

ISSN:0002-9629    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

To investigate the possible effect of heparin on coronary-collateral growth, dogs were instrumented chronically with a left circumflex (LCF) flow probe, an ameroid constrictor, a balloon occluder, and left and right atrial and aortic catheters. Collateral blood flow was measured at least weekly or when the coronary artery was occluded. Animals were allocated randomly to a control or treatment group. The latter received a continuous right-atrial infusion of a heparin solution at a rate of 2 to 3 ml/hour and a concentration adjusted daily to increase the activated clotting time to approximately 3 times the pre-drug level. After LCF occlusion, coronary-collateral flow was measured during exercise. There was no difference in time to LCF occlusion in the anticoagulated dogs. Furthermore, neither the rate of collateral development, the magnitude of collateral flow shortly after spontaneous LCF occlusion, nor the degree of collateral vascular reserve during exercise was different in the two groups. Therefore, in this model of coronary obstructive disease, heparin does not accelerate coronary-collateral development.

ISSN:0002-9629    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

This study attempted to determine the correlation between oxygen consumption (VO2), pulmonary-capillary blood flow (QEPC), and oxygen delivery (DO2) by rebreathing and invasive techniques obtained over a range of hemoglobin concentration and cardiac output.Twenty mongrel dogs were instrumented with central arterial and venous catheters to determine DO2by thermodilution cardiac output and standard formulas. The animals were administered isoproterenol in doses that increased DO2and subsequently were serially phlebotomized by 30%, 40%, and 50% to decrease DO2. All animals were studied using a rebreathing technique to determine noninvasively VO2, QEPCand DO2.Sixteen dogs completed the experimental protocol. A correlation analysis was carried out for VO2, QEPC, and DO2obtained by the rebreathing and invasive methods. Thermodilution cardiac output increased from 3.91 ± 1.77 L/min at baseline to 8.19 ± 2.50 L/min during isoproterenol infusion. Hemoglobin varied from 12.21 ± 1.26 gm% at baseline to 5.21 ± 1.36 g% at 50% phlebotomy. Over this range of conditions, significant correlations were obtained between rebreathing VO2and invasive VO2(r = 0.80, p < 0.0001), rebreathing QEPCand invasive QEPC(r = 0.79, p < 0.0001), and rebreathing DO2and invasive DO2(r = 0.82 p < 0.0001).These data demonstrate that the rebreathing technique can be used to monitor oxygen metabolism over wide ranges of DO2.

ISSN:0002-9629    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Various heterotrimeric GTP-binding proteins may have important functions in hematopoietic cells. There has been no comprehensive information, however, regarding their expression in various-lineage hematopoietic cells. In this report, the expression level of seven G protein α subunits (Gsα, Gi1α, Gi2α, Gi3α, Goα-1, Goα-2, and Gxα) in 13 hematopoietic cell lines were analyzed by Northern blot analysis. Gi1α, Goα-1, Goα-2, and Gxα, were expressed in a limited number of cell lines whereas Gsα, Gi2α, and Gi3α were expressed ubiquitously in nearly all cell lines tested. Gila was expressed selectively in a pre-T cell line, P30/PHK among lymphoid-lineage cell lines and a myeloblastic cell line, KG-1 among myelomonocytoid cell lines. Goα-1 was expressed only in a chronic myelocytic-leukemia cell line, K-562, whereas Goα-2 was not expressed in any cell lines tested after ordinary exposure of autoradiography (within 4 days). Gxα was expressed abundantly in a rat basophilic-leukemia cell line, RBL-2H3, and expressed in K-562. A barely detectable amount of Gxα messenger ribonucleic acid (mRNA) was found after a long exposure of autoradiography in several cell lines with megakaryoblastoid phenotype.

ISSN:0002-9629    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The objective-structured clinical examination (OSCE) is a useful tool in evaluating clinical competence. Traditional clinical-evaluation measures have been criticized as arbitrary and lacking reliability, whereas written exams test primarily cognitive aspects. The OSCE focuses on learner actions rather than abstract knowledge and evaluates in a uniform fashion. A 15-station OSCE was created for an internal medicine junior clerkship, based on predetermined skill and content goals. The exams then were scored by a single, blinded reviewer, again in a predetermined fashion. The OSCE has been studied in terms of reliability, content validity, and construct validity. The exam has become accepted by the department and has guided the continuing curricular development. The OSCE is not designed to measure all the domains of a learner's educational process. However, when used in conjunction with other evaluating mechanisms, it provides an objective outcome measure of the medical education process.

ISSN:0002-9629    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Patient compliance in returning fecal-hemoccult card packets has been studied in recent years but no specific interventions have been shown consistently to improve the return rate. It was wondered whether removing a small financial barrier for indigent patients would positively affect compliance. Therefore, the effect of prepaid postage on the rate of return was studied. Pre-prepared packets containing hem-occult cards with return envelopes were distributed in a randomized fashion to indigent and private insurance patients in outpatient clinics. On half of the return envelopes return postage was applied. The main outcome measure was the rate of return of stamped and unstamped packets stratified between indigent and private insurance patients. The overall rates of return were 117 of 159 (74%) for the stamped packets and 102 of 166 (61%) for unstamped packets (p < 0.02). After stratification, in the indigent patients (n = 177), 73 of 95 (77%) stamped packets were returned compared to 46 of 82 (56%) unstamped packets (p < 0.006). In the private insurance patients (N = 148), 44 of 64 stamped packets (69%) and 52 of 84 unstamped packets (62%) were returned (p > 0.10). Removing even small financial barriers (eg, providing a postage stamp) can enhance compliance for indigent patients.

ISSN:0002-9629    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Tuberculosis of the central nervous system remains quite rare in developed countries, accounting for only 0.53% of cases of tuberculosis in the United States. The most common form of intracranial tuberculosis is tuberculous meningitis; however, involvement may also take the form of a solid granulomatous mass (tuberculoma), which accounts for 15% to 30% of the neurosurgical cases in developing countries. An unusual case of a hypothalamic tuberculoma is presented in a man, who initially presented with signs and symptoms consistent with panhypopituitarism. Brain biopsy on two occasions confirmed caseating granuloma, and treatment with several antituberculous medications led to clinical improvement and radiographic resolution of the disease.

ISSN:0002-9629    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

A 55-year-old woman on chronic hemodialysis was treated for small-cell lung cancer and associated symptoms of a paraneo-plastic syndrome. Partial remission with an antineoplastic agent, an antineoplastic antibiotic, and vincristine was achieved. When the tumor advanced, carboplatin and etoposide resulted in a complete remission. Marked symptomatic improvement occurred with minimal side effects. Such examples indicate that carefully selected patients with renal failure may respond to chemotherapy and an improved quality of life.

ISSN:0002-9629    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The records were reviewed of five human immunodeficiency virus (HIV) type 1-infected patients who underwent splenectomy, four for HIV-associated thrombocytopenia and one for gastric compression secondary to splenomegaly. After splenectomy, the four adult patients all had marked, sustained increases in their absolute CD4 lymphocyte counts; greater increases were observed in CD8 lymphocyte counts, accounting for decreases in the CD4:CD8 ratios. In patient 5 (one of triplets, all of whom were infected with HIV after a blood transfusion), absolute CD4 lymphocyte counts were stabilized after splenectomy; the other siblings manifested a decline in CD4 counts, which was associated with a delay in physical development and recurrent episodes of varicella. Immunohistochemical staining of spleen sections demonstrated significantly higher numbers of CD4 cells in splenic tissue from HIV-infected patients than from patients splenectomized secondary to trauma (2,070 ± 284 vs. 962 ± 296; p = 0.025). In addition, the HIV-infected patients had significantly higher percentages of CD4 lymphocytes in splenic tissue than in peripheral blood (49.3 ± 11.0 vs. 20.3 ± 7.9; p = 0.005), suggesting that CD4 cells were sequestered in the spleens of these patients. These findings have implications for the management of splenectomized HIV-infected patients with regard to optimal timing of initiation of zidovudine therapy and for prophylaxis ofPneumocystis cariniipneumonia.

ISSN:0002-9629    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

In 1950, Carl John Wiggers, philosopher and physiologist, wrote, “Reactions to definite types of stimulation may be observed or recorded, and concealed phenomena may be revealed by the use of apparatus that transforms them into forms that are recognizable by human senses. But complete understanding of physiological reactions often necessitates extensive operative procedures and sometimes the ultimate sacrifice of life. For this reason experimentation on animals is indispensable.” Acute lung injury is still a significant cause of death in the developed world, and modern pharmacology and intensive care have failed to alter the clinical course of this complex condition. In the past decade, there was an explosion in understanding of the pathophysiology of acute lung injury, and with this has come the development of a new generation of agents that may provide a tool with which to combat this disorder. Use of animal model systems led to this greater understanding and is currently at the heart of evaluating the new therapeutic agents. This review briefly addresses the contribution animal model systems have made to what appear to be a watershed in attempts to obviate the effects of this mortal condition.

ISSN:0002-9629    

出版商:OVID    

年代:1993

数据来源: OVID