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Biomedical subjects

R Friedman

Publications and source records attributed to R Friedman.

At least 37 records · Page 2Linked to original sources
PubMed1991

Evolution of glomerular filtration rate in proteinuric NIDDM patients.

OBJECTIVE: To evaluate, by means of a precise method, the rate of decline of glomerular filtration rate in proteinuric non-insulin-dependent diabetic (NIDDM) patients. RESEARCH DESIGN AND METHODS: The study was comprised of seven NIDDM patients who visited an outpatient clinic and had a 24-h urinary protein excretion rate greater than or equal to 500 mg in the absence of heart failure, urinary tract infection, or other nephropathies. RESULTS: Glomerular filtration rate (51Cr-labeled EDTA, single-injection protocol) and 24-h proteinuria (turbidimetric method) were assessed at periodic intervals (2-6 mo). Correlation of the measurements with time (Pearson's r, with Student's t test used to assess the significance, alpha = 0.05) was used to evaluate the trend of evolution of glomerular filtration rate. Renal biopsies were performed in four patients. In three of four patients, renal histopathology was consistent with the diagnosis of diabetic nephropathy (in the 4th patient measurements were not satisfactory). Neither glomerular filtration rate nor proteinuria correlated significantly with time, except in one patient who had multiple myeloma. CONCLUSIONS: The decline of glomerular filtration rate in proteinuric NIDDM patients is different from that observed in insulin-dependent diabetic patients, which is probably much slower.

Aged↗
PubMed1991

An overview of chronic fatigue syndrome.

BACKGROUND: Psychological and immunologic factors both appear to contribute to chronic fatigue syndrome (CFS). By comparing CFS with other disorders in which fatigue is a prominent symptom, the association between fatigue, psychological vulnerability, depression, and immune function may be further defined. Recent data from psychological, neurologic, and immunologic studies that address these issues are reviewed. METHOD: Articles and abstracts covering CFS and related topics of fatigue, depression, and postinfectious syndromes were identified through MEDLINE and Index Medicus (1980-1990) and by bibliographic review of pertinent review articles. RESULTS: The 1988 definition of CFS by the Centers for Disease Control encompasses several conditions in which the major characteristic is severe fatigue associated with constitutional symptoms. Several studies have identified immune dysfunction in CFS patients, but the specificity of these findings remains unclear. Most studies have shown that CFS patients, compared with other patients with chronic medical illness, experience more disabling fatigue. Some investigators have found a higher incidence of concurrent and past psychiatric illness in CFS patients compared with other medical patients, thereby suggesting an underlying psychopathology in CFS. However, other studies have not found a higher than expected incidence of past depression in CFS patients and have further shown that many CFS patients have no identifiable psychopathology. CONCLUSION: CFS appears to be a heterogenous entity. Although there may be a high coincidence of major depression in CFS, a substantial proportion of patients lack any identifiable DSM-III-R psychiatric disorder yet still manifest the syndrome, thereby suggesting it has an autonomous entity. Despite the evolving nature of our current understanding of CFS, a rational diagnostic and therapeutic approach to CFS is possible.

Comorbidity↗
PubMed1990

Detection of breast abnormalities on teleradiology transmitted mammograms.

The authors conducted an observer performance study to compare breast lesion detection of conventional mammography (CM) with teleradiology (TE) transmitted mammograms. One hundred four abnormal, single-projection mammographic images were transmitted by teleradiology. Abnormalities included 11 cases with skin thickening or retraction, 48 cases with microcalcifications, and 52 with parenchymal masses. The CM and TE images were reviewed by four mammographers who indicated the type and location of abnormalities and a level of confidence for their diagnostic decisions. For each of three detection tasks--skin and nipple abnormalities, microcalcifications, and masses--receiver operating characteristic curve analysis was performed for individual readers and all readers as a group. For detecting skin and nipple abnormalities, readers performed significantly better with CM than with TE (z = 2.05, P = less than 0.04). However, no significant differences were found among readers for detection of either microcalcifications or masses. Further improvements in hardware and imaging parameters may improve detection of soft tissue abnormalities. Further evaluation is necessary to determine whether teleradiology might be applicable to breast cancer screening.

Breast Neoplasms↗
PubMed1990

Transcriptional regulation of the transforming growth factor beta 1 promoter by v-src gene products is mediated through the AP-1 complex.

Growth factor-independent 32D-src and 32D-abl cell lines, established by infecting the interleukin-3-dependent myeloid precursor cell line (32D-123) with retroviruses containing the src or abl oncogene, were used to study transcriptional regulation of transforming growth factor beta 1 (TGF-beta 1) mRNA. Analysis of different TGF-beta 1 promoter constructs regulated by pp60v-src indicated that sequences responsive to high levels of src induction contain binding sites for AP-1. Both src and serum induced expression of the c-fos and c-jun genes in myeloid cells, resulting in transcriptional activation of the TGF-beta 1 gene. We found that serum treatment increased TGF-beta 1 mRNA levels in 32D-123 cells and that the v-Src protein could replace the serum requirement by stimulating binding to the AP-1 complex of the TGF-beta 1 promoter, thereby mediating the induction of TGF-beta 1 transcription.

Animals↗
PubMed1990

Cerebral radioprotection by pentobarbital: dose-response characteristics and association with GABA agonist activity.

Pentobarbital reduces cerebral radiation toxicity; however, the mechanism of this phenomenon remains unknown. As an anesthetic and depressant of cerebral metabolism, pentobarbital induces its effects on the central nervous system by stimulating the binding of gamma-aminobutyric acid (GABA) to its receptor and by inhibiting postsynaptic excitatory amino acid activity. The purpose of this study is to investigate the role of these actions as well as other aspects of the radioprotective activity of pentobarbital. Fischer 344 rats were separated into multiple groups and underwent two dose-response evaluations. In one set of experiments to examine the relationship of radioprotection to pentobarbital dose, a range of pentobarbital doses (0 to 75 mg/kg) were given intraperitoneally prior to a constant-level radiation dose (70 Gy). In a second series of experiments to determine the dose-response relationship of radiation protection to radiation dose, a range of radiation doses (10 to 90 Gy) were given with a single pentobarbital dose (60 mg/kg intraperitoneally). Further groups of animals were used to evaluate the importance of the timing of pentobarbital administration, the function of the (+) and (-) isomers of pentobarbital, and the role of an alternative GABA agonist (diazepam). In addition, the potential protective effects of alternative methods of anesthesia (ketamine) and induction of cerebral hypometabolism (hypothermia) were examined. Enhancement of survival time from acute radiation injury due to high-dose single-fraction whole-brain irradiation was maximal with 60 mg/kg of pentobarbital, and occurred over the range of all doses examined between 30 to 90 Gy. Protection was seen only in animals that received the pentobarbital before irradiation. Administration of other compounds that enhance GABA binding (Saffan and diazepam) also significantly enhanced survival time. Ketamine and hypothermia were without protective effect. Protection from acute radiation-induced mortality by pentobarbital in the rat model is a reproducible phenomenon and is associated with the GABA agonistic activity of the compound. This property of GABA agonists offers the potential for a novel approach to enhancement of the efficacy of radiation therapy in the treatment of brain tumors.

Anesthesia, General↗
PubMed1979

Meningococcal sepsis with endophthalmitis.

Endophthalmitis is a rare complication of meningococcemia. A child had endophthalmitis as the initially occurring complaint. Although both eyes appeared inflamed, the pupil in the right eye was fixed and dilated, the fundus could not be seen, and a hypopyon was seen in the right anterior chamber. There was gradual improvement when the child received antibiotic therapy. Since the introduction of antimicrobial drugs, endophthalmitis has rarely been observed as a complication of meningococcal disease. However, this report is evidence that meningococcemia may occur with unusual sites of local infection.

Child, Preschool↗
PubMed1979

Differential development of salt-induced and renal hypertension in Dahl hypertension-sensitive rats after neonatal sympathectomy.

Rats with a genetic susceptibility to salt hypertension were given repeated neonatal injections of guanethidine. Vascular reactivity and tissue catecholamine concentrations indicated that a peripheral sympathectomy had been produced. Chemically sympathectomized rats had lower blood pressure than controls while fed a diet containing 0.4% NaCl. Furthermore, the dramatic rise in blood pressure exhibited by control rats fed a diet containing 8.0% NaCl was completely absent in sympathectomized rats similarly fed. The absence of salt-induced hypertension was observed regardless of whether the animals were anesthetized with ether or pentobarbital or had the blood pressures determined in an unanesthetized state. Finally, two-kidney Goldblatt hypertension did develop in sympathectomized rats, but to a level below intact rats similarly treated.

Angiotensin II↗
PubMed1978

Archival storage of clinical laboratory data.

This paper describes a data-base system for the maintenance of cumulative clinical data. A unique aspect of this data base is its ability dynamically to alter its two-level format to create an alternative three-level hierarchical structure in order to optimize retrieval efficiency. The relative advantages of these two types of data-base structures are discussed and examples of their use in clinical resrarch are presented.

Chemistry, Clinical↗