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Biomedical subjects

R L Vogel

Publications and source records attributed to R L Vogel.

At least 55 records · Page 3Linked to original sources
PubMed1993

Relationship of insulin secretory pulses to sex hormone-binding globulin in normal men.

Insulin has emerged as a regulator of sex hormone-binding globulin (SHBG) production in vitro and in vivo. A role for insulin in regulating SHBG exists in insulin resistant states such as obesity and polycystic ovary syndrome. The relationship of in vivo insulin secretion rates to SHBG levels in healthy normal men is less well documented. Hepatic synthesis of SHBG may be influenced by quantitative insulin exposure as well as qualitative characteristics such as frequency and amplitude of insulin secretory pulses. The present study was undertaken to assess these relationships in 10 normal men. Adiposity was determined by the body mass index and fat distribution by the waist hip ratio. Peripheral insulin sensitivity was determined by the euglycemic clamp technique at an insulin infusion rate of 287 pmol/min.m2. SHBG levels were determined in the fasting state by RIA. Arterialized venous samples for C-peptide were obtained every 2 min for 90 min in the basal state. Individual C-peptide kinetics were derived after a bolus injection of biosynthetic human C-peptide and a previously validated two compartmental model. Insulin secretion rates at each time point were calculated using the plasma C-peptide values and the C-peptide kinetics. Insulin secretion rates were unrelated to SHBG concentrations (r = -0.29, P > 0.05). The insulin secretory pulse interval had a significant positive association with SHBG levels (r = 0.86, P < 0.05). Insulin secretory pulse amplitude, body mass index, waist hip ratio, and peripheral insulin sensitivity were not associated with SHBG concentrations in a regression analysis. We postulate that insulin secretory pulse frequency may be an important determinant of SHBG synthesis in normal man.

Adipose Tissue↗
PubMed1993

Cardiac arrhythmias during performance of the flow-volume loop.

The purpose of our study was to determine the frequency of cardiac ectopy during the performance of flow-volume loops. The performance of an adequate flow-volume loop entails significant shifts in intrathoracic pressure and oxyhemoglobin saturation that could heighten myocardial arrhythmogenicity and lead to increased cardiac ectopy. Forty-two male patients referred for performance of flow-volume loops were studied with an ambulatory cardiac monitor and an arterial oxyhemoglobin saturation monitor during the performance of three flow-volume loops before and after administration of an aerosolized, selective beta 2-agonist. For comparison, the 60 min prior to and after completion of the loop testing was monitored with the continuous cardiac monitor. The frequency of cardiac ectopy was determined in four patient populations delineated by the presence or absence of cardiac, pulmonary, or cardiopulmonary disease. Each group was further divided based on the occurrence of arterial oxyhemoglobin desaturation during the performance of the flow-volume loop. We found that, despite the presence or absence of underlying cardiopulmonary disease or the occurrence of oxyhemoglobin desaturation during flow-volume loop performance, the number of cardiac ectopies diminished significantly during loop performance when compared with the 60-min study period prior to testing. This is in contrast to what had been reported previously. We conclude that the flow-volume loop is safe to perform in the general population, including those individuals with an increased risk of arrhythmias such as those with cardiac or pulmonary disease.

Aged↗
PubMed1993

Body fatness and smoking history predict the thermic effect of smoking in fasted men.

Epidemiological studies suggest that body composition and smoking history are related to degree of weight gain following smoking cessation. We hypothesized that body composition and smoking history affect the thermic effect of smoking (TES), which in turn would influence weight gain. Forty males ranging in age from 20 to 70 years smoked two cigarettes (0.8 mg nicotine yield) in 20 minutes, after which resting energy expenditure (REE) was measured during the next hour. The average change in REE (delta REE) was 4.97% (P < 0.0001), with a range of -2% to +14%. delta REE was greater than 1% in 35 subjects, less than 1% in three subjects, and reduced in two subjects. Body fatness was negatively correlated with delta REE (r = -0.68, r2 = 0.46). Multiple regression analysis indicated that body fatness (%) and pack-year history of smoking strongly predict delta REE (R = 0.82, R2 = 0.68; delta REE = 11.090-0.296 x %FAT-0.037 x pack-year). It was concluded that body fatness and smoking history substantially influence the thermic effect of smoking. In addition, this finding helps explain the wide range in TES which has been reported among subjects in many previous studies.

Adipose Tissue↗
PubMed1992

Side effects during continuous epidural infusion of morphine and fentanyl.

Respiratory effects, nausea, somnolence, and pruritus were compared during a 48-hr period of continuous epidural morphine (n = 34) and fentanyl (n = 32) infusion in 66 patients following elective total replacement of the hip or knee joint. Respiratory effects were assessed by PaCO2. Side effects were assessed by visual analogue scale and considered to be present when the score was above 30. Assessment was made at preoperative visits then 3, 6, 12, 24, 36, and 48 hr after the epidural injection. The bolus dose and subsequent infusion rate were 3,900 +/- 1,300 micrograms and 427 +/- 213 micrograms.hr-1 for morphine, and 85 +/- 46 micrograms and 56 +/- 27 micrograms.hr-1 for fentanyl. Pain relief was similar in both groups. In the morphine group, PaCO2 elevation and nausea occurred over a period of more than 12 hr (P less than 0.05). In the fentanyl group, there was no PaCO2 change, and nausea was confined to the first few hours. Nausea was more severe (P less than 0.01 at six hours and more frequent (24 hr cumulative incidence, 53 vs 28%, P less than 0.05) in the morphine group. Somnolence was prominent within several hours in two-thirds of patients in both groups. Somnolence continued to decline thereafter in the morphine group, but it was demonstrable in approximately half of the patients throughout the second day in the fentanyl group. The incidence was higher in the fentanyl group at the 48th hr (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Comparison of cardiac dimensions by transesophageal and transthoracic echocardiography.

Transesophageal echocardiography (TEE) has advanced rapidly as a valuable cardiovascular diagnostic technique. As the use of TEE increases, so does the importance of well-defined normal cardiac measurements. Presently, few data exist on the accuracy of M-mode TEE-derived measurements. Therefore in 81 adult patients, TEE-derived M-mode measurements were compared with analogous measurements that were made by standard M-mode transthoracic echocardiography (TTE). The TTE and TEE measurements did not differ in aortic root diameter, end-diastolic left ventricular diameter, end-diastolic septal wall versus anterior wall thickness, or end-diastolic posterior wall versus inferior wall thickness. These TEE measurements were within 95% confidence limits of TTE measurements. TEE-derived left atrial diameter (3.5 +/- 0.8 cm) was less than that derived by TTE (3.8 +/- 0.8 cm; p less than 0.001) and fell outside of the 95% confidence interval. TTE left atrial size could be estimated as follows: TTE-derived left atrial diameter = TEE-derived left atrial diameter x 0.6 + 1.5 cm. In conclusion, M-mode measurements of aortic root diameter, left ventricular diameter, and wall thicknesses as derived by TTE and TEE are comparable. TEE-derived left atrial diameter may be used to estimate the left atrial TTE measurement. TEE-derived M-mode measurements are likely to be most useful when results of TTE are technically inadequate.

Adolescent↗
PubMed1992

Body fat distribution and peripheral insulin sensitivity in healthy men: role of insulin pulsatility.

Abdominal fat distribution is associated with insulin resistance in healthy young men. Factors modulating this phenomenon remain unclear. Pulsatile insulin release has been implicated as a potential regulator of insulin action. The relationship of pulsatility of peripheral insulin levels to fat distribution and peripheral insulin sensitivity was examined in 10 healthy men. Fat distribution was determined by the waist to hip ratio. Peripheral insulin sensitivity was assessed by the euglycemic clamp at an insulin infusion rate of 287 pmol/min.m2. Pulsatility of insulin was assessed by sampling every 2 min for 90 min in the basal state. The characteristics of insulin pulses were assessed by the computer program Pulsar. The waist to hip ratio was negatively associated with insulin sensitivity (r = -0.70, P less than 0.05) and insulin pulse interval (r = -0.66, P less than 0.05). The insulin pulse interval was positively correlated with peripheral insulin sensitivity (r = 0.73, P less than 0.05). The insulin interpulse interval was the primary determinant of insulin sensitivity. The increased frequency of insulin pulses may play a role in inducing insulin resistance in individuals with abdominal fat distribution.

Abdomen↗
PubMed1991

Diminished IgG, but not complement C3 or C4 or factor B, precedes nosocomial bacterial sepsis in very low birth weight neonates.

The significance of low serum IgG and complement proteins in very low birth weight (VLBW; less than 1500 g) neonates is not known. Therefore serum IgG, C3, C4 and Factor B were quantitated weekly by rate nephelometry in 15 VLBW neonates who developed proven nosocomial bacterial or candidal sepsis (Group A) and 27 VLBW neonates who did not develop sepsis (Group B). In the first week of life the serum IgG of neonates in Group A was 295 +/- 33 mg/dl (mean +/- SEM) and in Group B it was 440 +/- 21 mg/dl (P less than 0.01). In the second week, the IgG of Group A was 270 +/- 32 mg/dl and that of Group B was 473 +/- 38 mg/dl (P less than 0.01). If the IgG was less than 350 mg/dl in the first week or less than 230 mg/dl in the second week, the relative risk of acquiring sepsis was greater than or equal to 5 (95% confidence interval in the first week, 1.7 to 11.2). The serum IgG was measured before the onset of sepsis in 14 of the 15 neonates in Group A. In the week before sepsis the IgG of the 14 neonates was less than 440 mg/dl (range, 45 to 433 mg/dl) in all cases, was below the mean IgG of Group B in 12 of 14 cases (P = 0.006 vs. Group B) and was greater than 2 SD below the mean IgG of Group B in 4 of 14 cases (P = 0.0003 vs. Group B).(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1990

Identification of a DNA sequence responsible for binding of the 1,25-dihydroxyvitamin D3 receptor and 1,25-dihydroxyvitamin D3 enhancement of mouse secreted phosphoprotein 1 (SPP-1 or osteopontin) gene expression.

Secreted phosphoprotein 1 (Spp-1; osteopontin) is one of the abundant noncollagenous proteins in bone matrix and is produced by osteoblasts. We examined the promoter region of the mouse Spp-1 gene and identified a sequence responsible for 1,25-dihydroxyvitamin D3 enhancement of the Spp-1 gene expression. This 24-base-pair (bp) sequence (vitamin D response element) is located 761 bp upstream of the transcription start site and consists of two direct repeats of a unique 9-bp motif, AGGTTCACG. The vitamin D response element confers responsiveness of a heterologous promoter to 1,25-dihydroxyvitamin D3 in a position- and orientation-independent and copy-number-dependent manner. The basal level of expression of the reporter constructs containing this sequence and its response to 1,25-dihydroxyvitamin D3 were not affected by cotreatment with transforming growth factor beta or the tumor promoter phorbol 12-myristate 13-acetate or by cotransfection with a JUN expression vector. The vitamin D response element forms DNA-protein complexes, as indicated by gel-retardation assays. The addition of a monoclonal antibody raised against the vitamin D receptor further retarded the mobility of the DNA-protein complex. Another antibody that recognizes the DNA binding region of the vitamin D receptor attenuated its binding to the sequence. These results indicate that this 24-bp sequence containing two 9-bp motifs binds to the vitamin D receptor and mediates the vitamin D3 enhancement of murine Spp-1 gene expression.

Animals↗
PubMed1990

Leukemia inhibitory factor suppresses proliferation, alkaline phosphatase activity, and type I collagen messenger ribonucleic acid level and enhances osteopontin mRNA level in murine osteoblast-like (MC3T3E1) cells.

The effect of leukemia inhibitory factor (LIF) on proliferation and phenotypic expression in murine osteoblast-like (MC3T3E1) cells was examined. LIF inhibited the proliferation of these cells by up to 20% and DNA synthesis was inhibited in a dose-dependent manner with an ED50 of about 0.2 ng/ml. The effect of LIF relative to matched controls increased with decreasing serum concentration, reaching 30% inhibition at 0.2% serum. LIF also reduced the stimulatory effects of platelet-derived growth factor and insulin-like growth factor I on DNA synthesis. The inhibition of the DNA synthesis by saturating concentration of transforming growth factor beta was further enhanced by the addition of LIF, suggesting independent pathways for the action of the two growth inhibitors. In addition, LIF reduced alkaline phosphatase activity and the abundance of type I collagen messenger RNA, but increased the level of osteopontin messenger RNA. These findings suggest that LIF may play a role in regulating the function of osteoblasts.

Alkaline Phosphatase↗
PubMed1989

Experience with the polytetrafluoroethylene surgical membrane for pericardial closure in operations for congenital cardiac defects.

From 1984 through 1987, pericardial closure for 96 patients who underwent repair of congenital heart defects was completed with placement of a polytetrafluorethylene surgical membrane. Ages ranged from 1 day to 20 years (median age 2.1 years), and weight ranged from 2.7 to 44.6 kg (median weight 10.7 kg). Use of the membrane increased over the 4-year period. The patients were divided into three groups according to probability of reoperation: group I, low probability (35 patients); group II, intermediate probability (41 patients); and group III, high probability (20 patients). Early postoperatively there were no infections in any group and no complications attributable to the polytetrafluoroethylene membrane. No increase in pericardial drainage was found when the studied patients were compared to similar groups without the membrane. There were a total of 17 deaths (17.7%): group I, 1/35 (2.8%); group II, 9/41 (21.9%); and group III, 7/20 (35%). None of the deaths could be attributed to placement of the polytetrafluorethylene membrane. Seven patients had a second operation, which made possible the in vivo evaluation of the membrane. In addition, there was one late death, which allowed an autopsy. Findings were similar in all eight. There were no adhesions between the chest wall and the membrane. The latter had basically become transparent and was loosely attached to the epicardium. On the epicardial surface there was a thin layer of collagenous fibrous tissue that did not interfere with the visualization of the heart anatomy, including the coronary vessels. At early postoperative follow-up, difficulty in evaluation of the patient by two-dimensional echocardiography was encountered only in the parasternal view, but not in the other scans. In the parasternal view, the membrane is between the echo transducer and the heart and there is moderate blurring of finer details of the cardiac architecture. At late postoperative ultrasound study, resolution of the images in the parasternal views is much better. The following conclusions were reached: (1) Polytetrafluorethylene surgical membrane can be used for pericardial closure; (2) reoperation shows no adhesions to the chest wall or epicardium, and visualization of the cardiac surface, especially of the coronary vessels, is not obscured; (3) the membrane causes some difficulty in the echocardiographic examination of patients in the parasternal views, but other views allow for a complete postoperative evaluation of the heart.

Adolescent↗
PubMed1988

Heparin potentiates endothelial cell growth factor stimulation of plasminogen activator synthesis by diploid human lung fibroblasts.

Endothelial cell growth factor (ECGF) stimulates the synthesis of t-PA and u-PA by confluent, diploid human lung fibroblasts, and this activity is potentiated considerably by heparin. In contrast, the malignant cell lines, Bowes melonoma and CALU-3, producers of t-PA and u-PA, respectively, are insensitive to ECGF. Studies with metabolic inhibitors and direct measurements of PA-specific mRNAs show that ECGF-mediated production of PA by human lung fibroblasts is dependent on de novo protein and RNA synthesis. The mechanism by which heparin potentiates this effect is thought to reside in its ability to prolong or strengthen the interaction of ECGF with cell surface receptors. The results raise the possibility that endogenous ECGF or related polypeptides (and heparin) may act to regulate PA synthesis by lung fibroblasts and possibly other responsive target cells in vivo.

Cells, Cultured↗
PubMed1983

Effects of allopurinol in Duchenne's muscular dystrophy.

There is no effective treatment at present for Duchenne's muscular dystrophy (DMD). Recently, clinical improvement and increased muscle strength have been reported after 100 mg of allopurinol was administered daily to 21 boys with DMD in a double-blind crossover study. Its effectiveness was determined by an extensive battery of muscle function, cardiac, and laboratory tests. The ten-month study was divided into four periods; (1) one month of baseline observation; (2) three months of therapy to allopurinol and placebo control groups; (3) three months of therapy to crossed over groups; and (4) three months of therapy to all patients. No statistically significant changes between the allopurinol and control periods occurred in the muscle function tests. The earlier report of clinical improvement during allopurinol treatment was not confirmed.

Adolescent↗
PubMed1983

Macrophages: a source of luteotropic cybernins.

A macrophage homogenate contained substances which stimulated primary cultures of mouse granulosa cells to secrete more progesterone. The response to the luteotropic substances was similar to that observed when intact macrophages were co-cultured with granulosa cells. The bioactive polypeptides present in cytosolic and particulate fractions of cell homogenates were non-dialyzable, heat labile and trypsin sensitive. When the surface of intact macrophages was treated with trypsin there was a loss of activity from the particulate fraction suggesting that some luteotropic proteins reside on the plasma membrane of mononuclear phagocytes. Treatment of macrophages with Con A but not the succinyl derivative of the lectin caused a release of luteotropic proteins with apparent molecular weights of 26,000 and 41,000. These findings in conjunction with our prior observation that macrophages must contact granulosa cells to stimulate progesterone secretion suggest that aggregation of mononuclear cell surface proteins may occur when the two cells interact thus resulting in the expression of luteotropic activity. Hence, it appears that macrophages which are found within corpus luteum may be a source of ovarian cybernins. This is the first description that a cell of the immune system can communicate at the molecular level with a steroid secreting cell of the ovary.

Animals↗
PubMedDate not supplied

Sudden death in childhood due to right ventricular dysplasia: report of two cases.

Two cases of sudden death due to arrhythmogenic right ventricular dysplasia (ARVD) occurring in the pediatric age group are described. One of the subjects, at the age of 7 years, is believed to be the youngest child in whom ARVD has been diagnosed at autopsy. The clinical and pathological characteristics of ARVD are discussed.

Adolescent↗
PubMedDate not supplied

The False Claims Act and clinical laboratories.

In its efforts to fight fraud, the government has turned increasingly to the civil False Claims Act. The Act imposes triple damages plus monetary penalties against those who defraud the federal government. The Act also encourages whistleblowers to report fraud by offering the prospect of large bounties. This article describes the False Claims Act, its qui tam provision dealing with whistleblowers, and the application of the Act to clinical laboratories.

Fraud↗