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Biomedical subjects

B Friedman

Publications and source records attributed to B Friedman.

At least 109 records · Page 6Linked to original sources
PubMed1989

In situ demonstration of mature oligodendrocytes and their processes: an immunocytochemical study with a new monoclonal antibody, rip.

This paper introduces "Rip" a monoclonal antibody that produces relatively complete staining of oligodendrocytes and their processes in the adult central nervous system (CNS). The distribution of Rip immunoreactivity coincides with that of myelinated axons in both the spinal cord and the cerebellum. In addition, double-immunolabeling experiments demonstrate that Rip stains processes containing myelin basic protein but does not stain processes that express glial fibrillary acidic protein. These results indicate that Rip selectively stains oligodendrocytes but not astrocytes. Moreover, individual Rip-stained oligodendrologial somata and their cytoplasmic processes were observable at both the light microscopic and electron microscopic level when the staining of myelin was reduced. This was accomplished by omitting detergents from antibody incubation steps. Rip-stained oligodendrocytes have multiple processes of varying thickness, some of which end in close proximity to myelin sheaths. These immunostained profiles, reminiscent of those observed in oligodendrocytes stained by Golgi methods, are unique to Rip and indicate that its immunoreactivity is distinct from that of existing serological markers for oligodendrocytes.

Animals↗
PubMed1989

Geographic differences in the use of Veterans Administration hospitals.

This study contrasts the determinants of community hospital utilization with Veterans Administration (VA) hospital utilization using traditional planning variables. The comparisons had some expected and some unanticipated findings. Regional differences in non-VA hospital admissions and bed days are fairly well explained by measures of medical need, provider supply, community alternatives, and sociodemographic characteristics (other than those used as proxies for case mix). However, regional variations in the VA are explained less well by the same classes of variables and the unexplained differences between the two systems do not correspond geographically. This suggests that the two systems have different reasons for regional variation. Further, contrary to expectation, when other predictors are held constant, excess bed capacity in the area does not correlate with lower VA utilization. The study is important as the VA comes under increasing pressure to contain costs. It may well be that the rational planning model attributed to the public sector is less likely to overcome maldistribution than the private sector 'invisible hand'. Policy analysts need to give more attention to the political, bureaucratic determinants of resource allocation before changing eligibility criteria or merging the two systems.

Adult↗
PubMed1989

Antigenic abnormalities in fiber tract astrocytes of myelin-deficient rats: an immunocytochemical study in the olfactory cortex.

Intrafascicular oligodendrocytes in myelin-deficient (md) rats typically fail to form myelin sheaths or survive to maturity. The present study of the md olfactory cortex compares astrocytes that develop either among populations of pathological oligodendrocytes in a fiber tract or that develop in neuropil, which normally contains few oligodendrocytes. Antigenic profiles for md and normal astrocytes were defined by the monoclonal antibody Rat 401, and by antibodies that recognize vimentin and glial fibrillary acidic protein. In the olfactory cortex, antigenic abnormalities were typically restricted to astrocytes located in the vicinity of pathological oligodendrocytes.

Animals↗
PubMed1988

Thapsigargin, a novel promoter, phosphorylates the epidermal growth factor receptor at threonine 669.

Thapsigargin, a protein kinase C-independent tumor promoter, can negatively regulate the epidermal growth factor (EGF) receptor through inhibition of high affinity EGF binding and EGF-stimulated tyrosine kinase activity. In contrast to activators of protein kinase C, thapsigargin does not induce significant phosphorylation of threonine 654. However, thapsigargin does stimulate phosphorylation of the EGF receptor at other serine and threonine residues. We now identify threonine 669 as the major site of phosphorylation on the EGF receptor resulting from thapsigargin treatment. These results raise the possibility that phosphorylation of threonine 669 may mediate changes in the binding and kinase state of the EGF receptor.

Amino Acid Sequence↗
PubMed1988

Prolonged corticosteroid treatment in the management of temporal arteritis.

Twenty-four patients with biopsy proven temporal arteritis were followed for 7 years and the effect and duration of corticosteroid treatment was evaluated. An initial dose of 35 mg prednisone daily was sufficient to control symptoms and signs in most of the patients. Flare-up rates upon corticosteroid reduction were high, especially in the first 24 months of treatment. Flare-ups were more common (greater than twice) in "non-western" Jews as compared to "western" Jews. Serious corticosteroid side effects were uncommon. Corticosteroid treatment was withdrawn from 7 patients after 5 years; two of these patients suffered flare-ups within 16 months. Nineteen patients remained on prednisone, in an average dose of 4 mg/day, 7 years after diagnosis. Thus, corticosteroid treatment in temporal arteritis should be prolonged in the majority of patients.

Aged↗
PubMed1988

Scintigraphic presentation of hip joint synovial chondromatosis.

A case of hip joint synovial chondromatosis with an unusual scintigraphic pattern is described. This pattern was suggestive of a hip joint destructive reactive articular process or late manifestations of avascular necrosis of the femoral head. Concurrent radiographs were normal, as were laboratory investigations. Follow-up radiographs six months later showed radiolucencies and erosive bone changes in the diseased joint. Surgical and histopathological findings revealed well developed hip synovial chondromatosis (HSC) with thickened synovium and large, loose, cartilaginous bodies occupying and widening the tightened joint space, with destructive secondary juxta articular pressure and bone erosions. This and other scintigraphic patterns in HSC, and the differential diagnosis of the findings in patients with painful hip presentations are discussed.

Chondroma↗
PubMed1988

Aneurysmal bone cyst of the rib: a review and report of two cases.

Aneurysmal bone cyst (ABC) is a benign lesion and generally occurs in the long bones and vertebral column. ABC of the rib is an uncommon entity. Two cases of ABC involving the rib are reported. Its occurrence in the eight decade of life as manifested in one of our patients is extremely rare. The aetiology, clinical manifestations, pathology and treatment are briefly discussed. En bloc resection of the lesion is curative, and offers a good cosmetic and functional result.

Adult↗
PubMed1988

Self-inflicted hand injuries: diagnostic challenge and treatment.

Self-inflicted injuries are probably more common than is generally appreciated. Three patients with self-inflicted hand injuries are described. A delay in making the correct diagnosis resulted in severe hand disability in 2 of the patients. Early diagnosis of this entity, combined with prompt psychotherapy, prevented disability in the third. The pertinent literature is reviewed and the importance of early diagnosis and psychotherapy is stressed.

Adolescent↗
PubMed1988

Effect of coronary artery revascularization on left and right ventricular ejection fractions during rest and exercise.

We have reported a case of a 55-year-old man who had improvement of both left and right ventricular ejection fractions during rest and exercise after coronary revascularization. Ventricular performance was assessed using radionuclide angiography. Although coronary artery bypass grafting has previously been shown to improve left ventricular function, we believe this is the first report of improved right ventricular function after coronary revascularization.

Coronary Artery Bypass↗
PubMed1988

The need for special interventions for multiple hospital admission patients.

Although a high proportion of Medicare hospital admissions and expenditures are accounted for by a small proportion of the elderly who experience chronic patterns of acute hospital use, little emphasis has been placed on reducing hospitalization among these high users. Five interventions that have succeeded in substantially reducing the number of hospital days among high users living at home are discussed in this article, as are several interventions that have reduced hospital use by nursing home residents. With the passage of the Medicare Catastrophic Coverage Act of 1988, research and demonstration activities for high users of hospital care will, for the first time, have a Federal focus.

Aged↗
PubMed1988

The financial performance of selected investor-owned and not-for-profit system hospitals before and after Medicare prospective payment.

This article analyzes determinants of cost and profitability, including the influence of Medicare prospective payment (PPS), between 1983 and 1985 for nearly 300 hospitals belonging to investor-owned (IO) and not-for-profit (NFP) systems. Using approaches that assure comparability of financial data, and including case mix, quality, competition, and regulation measures, the findings indicate that (1) in both years, competitive environment, case mix, age of facility, and scope of diversified services were important determinants of average cost, while a process measure of quality was insignificant and the independent effect of ownership type was insignificant for cost; (2) effects of HMO competition and hospital strategy were stronger in 1985 than in 1983; (3) operating margins for all types of hospitals showed increases, with a somewhat greater improvement for NFP system members; and (4) significantly greater declines in volume of care occurred for IO system members. Implications for future research are discussed.

California↗
PubMed1988

Transferrin iron interactions with cultured hepatocellular carcinoma cells (PLC/PRF/5).

Hepatocellular carcinoma cells of the PLC/PRF/5 cell line had 1.9 x 10(5) transferrin receptors per tumor cell with a Kd of 1.5 x 10(-8) M. At high concentrations of transferrin the binding was not saturable. Transferrin internalization by hepatoma cells was shown by time and temperature-dependent binding studies and by pronase experiments. Transferrin recycling was confirmed by the demonstration of a progressive increase in the cellular molar ratios of iron to transferrin and by chase experiments. Ammonium chloride interfered with iron unloading. The vinca alkaloid vincristine inhibited iron and transferrin uptake. The hepatocarcinoma cells appeared to lack asialoglycoprotein receptors and therefore internalized partially desialated transferrin by the regular route. Iron uptake from transferrin was markedly inhibited by the hydrophobic ferrous chelator 2,2' bipyridine but was relatively unaffected by the hydrophilic ferric chelator desferroxamine. The implication that ferrous iron was involved in postendocytic transvesicular membrane iron transport was supported by a study in which hepatoma cells were shown to take up large amounts of ferrous iron suspended in 270 mM sucrose at pH 5.5. The interaction at this pH between surface labeled hepatoma cell extracts and ferrous iron on a Sephacryl S-300 column suggested that the postendocytic transvesicular transport of iron through the membrane was in part protein mediated. The endocytosed iron in hepatoma cells was found in association with ferritin (33%), transferrin (31%) and a low molecular weight fraction (21%).

2,2'-Dipyridyl↗
PubMed1988

Synovial chondromatosis of the hip joint.

Synovial chondromatosis of the hip joint is uncommon entity. Two cases are presented, and the spectrum of the disease is discussed. Partial synovectomy with loose body removal is recommended as the treatment of choice. Joint replacement is performed only in patients with severe secondary osteoarthritis, and used only in selected cases.

Adult↗