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Biomedical subjects

F Singer

Publications and source records attributed to F Singer.

At least 19 recordsLinked to original sources
PubMed1992

Subnormal serum testosterone levels in male internal medicine residents.

The consequences of sleep deprivation and stress in residency training have not been quantified. In the course of assembling a control group for other studies, we unexpectedly observed a significant (P less than 0.005) and marked depression of serum testosterone levels in healthy male internal medicine residents (means = 11.8 +/- 1.1 nmol/L, n = 7) compared with other hospital personnel (means = 20.6 +/- 5.3 nmol/L, n = 18). Testosterone concentrations in the two groups were entirely nonoverlapping, while luteinizing hormone levels were not significantly different. We conclude that the stress of residency training leads to a quantifiable depression of gonadal function, and that gonadal steroid concentrations may be useful in evaluating measures intended to reduce that stress.

Humans↗
PubMed1992

Ventilatory effects of dexmedetomidine, atipamezole, and isoflurane in dogs.

Dexmedetomidine (DMED) is a novel alpha 2 adrenergic agonist that has been shown to have potent analgesic and anesthetic sparing effects. This study was designed to investigate the effects of DMED, both alone and combined with isoflurane, on resting ventilation, the hypercapnic response, and the hypoxic response in dogs. When given alone, 1 microgram/kg decreased resting ventilation by 22% but at larger doses (10, 20, and 100 micrograms/kg) resting ventilation increased, doubling at 100 micrograms/kg. Doses of 10 micrograms/kg and greater caused a maximum depression of 60% in the slope of the hypercapnic response, but no dose had a significant effect on the hypoxic ventilatory response. A dose of 3 micrograms/kg of DMED reduced isoflurane MAC from 1.3% to 0.37%, and the ventilatory effects of this 1 MAC combination were intermediate between the awake values and those of isoflurane-anesthetized (1.3%) dogs. Atipamezole is a specific centrally acting alpha 2 receptor antagonist and when given with DMED in isoflurane-anesthetized dogs prevented the ventilatory depression. However, atipamezole alone also ventilatory stimulating effects, which may indicate tonic alpha 2 adrenergic activity. The ventilatory depression caused by DMED, either alone or combined with isoflurane, at doses that significantly reduce anesthetic requirements are relatively mild.

Adrenergic alpha-Agonists↗
PubMed1991

Case report: dextran-induced acute anuric renal failure.

Acute renal failure is an infrequent adverse reaction following the administration of dextran-40. We report a case of anuric acute renal failure in a 59-year-old female following the administration of 90 gm of dextran-40 and radiocontrast. An increased risk secondary to radiocontrast-induced ischemia is discussed in relationship to the pathogenesis of the dextran-induced acute renal failure. In addition, plasmapheresis is demonstrated to be of potential therapeutic benefit.

Acute Kidney Injury↗
PubMed1991

Adrenal carcinoma presenting with postmenopausal vaginal bleeding.

A 63-year-old woman presented with a 3-day history of vaginal bleeding. Pelvic examination and ultrasound revealed bilateral atrophy of the ovaries and a uterus of 8.8 x 3.3 x 4.0 cm. Serum estradiol (E2) was 300 pg/mL. Cushing syndrome was diagnosed biochemically, and computed tomography of the abdomen revealed a 5-cm left adrenal mass and tumors in the liver and lung. A pathologic diagnosis of metastatic adrenal carcinoma was made after surgery. This case demonstrates that adrenal carcinoma can produce high E2 levels in a postmenopausal woman, leading to uterine enlargement and vaginal bleeding. Adrenal carcinoma should therefore be included in the differential diagnosis of postmenopausal vaginal bleeding.

Adrenal Gland Neoplasms↗
PubMed1991

Endocrine complications of AIDS and drug addiction.

The endocrine and metabolic consequences of illicit drug use and HIV disease are extensive and profound. Both narcotic drug use and AIDS have the capacity to cause clinically significant multiglandular derangements. Admittedly, we were not able to focus as much attention on the less frequently occurring disturbances of calcium, phosphorus, or folate metabolism in HIV disease. Similarly, we reported very little information about the endocrinologic significance of the use of classes of narcotics other than opiates and to a far lesser extent cocaine. Even with these limitations, the spectrum of drug abuse and HIV-related endocrine manifestations discussed previously is quite diverse. Given the pervasive effects of drug abuse on other organ systems, it is not surprising to find expanding interest in the endocrine consequences of narcotic drug use. In fact, the use of these drugs is responsible, in part, for the past and continuing interest in identifying receptors for these agents and similarly structured endogenous ligands. As these investigations proceed, we must appreciate the limitations in translating basic and clinical scientific findings to the clinical setting. Much of the current research does not study street-relevant narcotic doses, does not use research designs involving polydrug use, and does not involve the processes or routes of drug administration used by active narcotic addicts. There is a critical need for more research methods with animal models and clinical study settings that more adequately mimic drug use outside of the laboratory. Our ability to develop appropriate psychopharmaceutical agents to respond to the different faces of drug abuse in the United States will depend on continued progress in the area of neuroendocrinology. With respect to the consequences of HIV disease, the clinical findings of elevated hormonal levels in some endocrine systems are amazing given what one would expect if one postulated direct or indirect destruction by HIV or the opportunistic complications that accompany AIDS. In unraveling this puzzle, careful attention must be given to evaluating the degree to which the clinical or biochemical consequences are due to a direct HIV effect, to an effect of a complicating infection or neoplasm, or to an AIDS-related therapeutic intervention. More work is needed also in obtaining histopathologic information to correlate with the biochemical and clinical derangement. In summary, there is a wealth of information demonstrating a wide spectrum of endocrine/metabolic consequences of drug abuse and AIDS. Still, just as many questions remain unanswered. While the exact biologic mechanisms are unclear, many of the biochemical aberrations have clinical relevance.(ABSTRACT TRUNCATED AT 400 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1990

Lymphocyte cell lines from vitamin D-dependent rickets type II show functional defects in the 1 alpha,25-dihydroxyvitamin D3 receptor.

Lymphocyte cell lines were established from five patients with vitamin D-dependent rickets, type II (VDDR-II). These lines were established by infection with human T-lymphotrophic virus type I (HTLV-I). Binding of [3H]1 alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) to its receptor in these cell lines was compared to binding studies using a T-lymphocyte cell line (S-LB1) from a normal individual. The 1,25(OH)2D3 receptor of S-LB1 was comparable to the well-characterized chick intestinal 1,25(OH)2D3 receptor in terms of its ligand binding affinity and capacity, its mobility on 5-20% sucrose gradients, and its adsorption to and elution properties from DNA-cellulose. Three cell lines established from patients with VDDR-II (Rh-VDR, Sh-VDR, and Ab-VDR) showed no specific binding of 1,25(OH)2D3 to a receptor and treatment of the cultured cells with 1,25(OH)2D3 did not stimulate production of 24,25-dihydroxy-vitamin D3 (24,25(OH)2D3), a response which is diagnostic of the presence of a functional 1,25(OH)2D3 receptor. In a fourth cell line, A1-VDR, the receptor for 1,25(OH)2D3 had a low binding capacity and 25(OH)D3-24-hydroxylase activity was not detectable. Induction of 24,25-(OH)2D3 synthesis by 1,25(OH)2D3 was observed in the fifth cell line, designated Ro-VDR, although the sensitivity to hormone treatment was lower than in the control cell line from a normal donor. The capacity of the receptor for 1,25(OH)2D3 was low in Ro-VDR. In all cell lines where 1,25(OH)2D3 binding to a receptor was detectable, the receptor had the typical sedimentation coefficient of 3.7 S on sucrose density gradient analysis. Binding and elution properties to DNA-cellulose, however, differed from normal in both Ro-VDR and A1-VDR cells where elution from DNA-cellulose occurred at a lower salt concentration than is typical of the 1,25(OH)2D3 receptor. While Ro-VDR cells showed typical nuclear localization of the unoccupied 1,25(OH)2D3 receptor, neither the unoccupied nor the occupied receptor from A1-VDR cells was completely localized in the nucleus. In a series of functional studies we found that modulation of the level of the mRNAs coding for both the c-myc oncogene and the growth factor known as granulocyte-monocyte colony stimulating activity by 1,25(OH)2D3 correlated with the 1,25(OH)2D3 receptor status of these cells. Use of these cell lines will facilitate further study of the molecular defect(s) in the receptor for 1,25(OH)2D3 in vitamin D-dependent rickets type II and will allow a correlation with impairment of cellular functions.

24,25-Dihydroxyvitamin D 3↗
PubMed1989

Elevated levels of angiotensin-converting enzyme in Pneumocystis carinii pneumonia.

Serum angiotensin-converting enzyme (ACE) levels are elevated in sarcoidosis and have been used both to diagnose and to assess response to treatment of this disease. We report significantly (p less than .0005) elevated ACE levels in patients with Pneumocystis carinii pneumonia (PCP) (49 +/- 14 U/L) compared with normal control subjects (32 +/- 11 U/L) tested within 48 hours of hospital admission. Serum ACE levels in smoking control subjects (33 +/- 11 U/L) were not significantly (alpha = .05) different from nonsmoking control subjects (32 +/- 11 U/L), but the levels in PCP patients who smoked (55 +/- 15 U/L) were significantly (p less than .025) higher than in those who did not smoke (42 +/- 10 U/L). In addition to suggesting a possible clinical use for measuring ACE levels in suspected or confirmed PCP, we speculate that elevations in serum ACE levels may reflect macrophage dysfunction in patients with PCP.

Acquired Immunodeficiency Syndrome↗
PubMed1987

[Rehabilitation of cerebral apoplexy--results based on 156 patients].

156 stroke patients were followed-up over a period of up to twelve months from the event. During that period they had participated repeatedly, or continually, in comprehensive inpatient rehabilitation programmes at the Bad Schallerbach rehabilitation centre, Austria. The services provided were characterized by a comprehensive medical, vocational and social orientation. Rehabilitation outcome assessment related to personal functioning levels (ADL performance, intellectual functioning, communication, social behaviour, etc.) as well as the basic working capacity. Based on medical findings, the results stated toward the end of our comprehensive rehabilitative efforts showed improvements of personal functioning by about 66 percent, and attainment of a basic working capacity in 22 percent of the patients. Outcomes varied for the different causes of stroke; three patients had died during the observation period due to renewed stroke. The principles to be observed in comprehensive rehabilitation are discussed, with special emphasis on those in stroke rehabilitation.

Activities of Daily Living↗
PubMed1986

Segregation analyses and gene-centromere distances in zebrafish.

The gol-1, gol-2, alb-1 and spa-1 mutations affect pigment pattern in the zebrafish. We show here that these loci are unlinked to each other. In addition, gene-centromere distances were determined for these loci by analysis of half-tetrads obtained by the inhibition of the second meiotic division. The fractions of tetratype (second-division segregation) tetrads range from 0.24 (spa-1) to 0.89 (gol-1). The observation of greater than 0.67 second-division segregation indicates that the zebrafish has high chiasma interference.

Animals↗
PubMed1986

[Occupational factors in rheumatic diseases as a principle of rehabilitation--analysis of patients of the pension insurance administration for workers in Austria].

The study evaluates unselected "blue-collar" patients (n = 642) included under the social insurance law guidelines of rehabilitation. Rehabilitation measures had become necessary in these patients because of existing or impending invalidity in diseases of rheumatic origin. In 421 patients (= 66%), a connection with the place of work appeared possible. This entailed adaptation or change of the place of work in 297 patients (= 71%), the result of these measures after a period of two to three years being described. General aspects of occupational rehabilitation measures are discussed.

Arthritis, Rheumatoid↗
PubMed1985

[Results of electromyographic studies with central muscle relaxants--feasibility of objectivization and standardization].

The following drugs, mostly postulated acting at a supraspinal or spinal level as diazepam, chlormezanone and orphenadrine citrate were proved for their effectiveness in lessening tension of muscles. This was assessed by electromyography recording different neurophysiological phenomenons as mono- and polysynaptic reflex responses (H-reflex and unloading reflex as a result of a suddenly muscle relaxation (= post-reflex inhibition phase/silent period) and tiredness reaction. This investigations were performed on at least 65 patients. The outcomes are: statistical significant increase of the silent period of the unloading reflex under the treatment with diazepam and orphenadrine citrate. Diazepam also extended the time between the initial electric stimulus and H-reflex phenomenon. Evaluating these results it might be obvious that diazepam is acting on supraspinal level and the spinal too, orphenadrine citrate only on the supraspinal one. Chlormezanone showed no effect according to that protocol on all mentioned neurophysiological parameters.

Adult↗