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Biomedical subjects

R Stern

Publications and source records attributed to R Stern.

At least 199 records · Page 11Linked to original sources
PubMed1985

Paradoxes faced by residents being trained in the psychosocial treatment of people with chronic schizophrenia.

The authors describe seven paradoxes that confront psychiatric residents being trained in the psychosocial treatment of chronic schizophrenic patients in community settings. The paradoxes arise because the psychosocial framework necessary for working with such patients challenges the residents' strongly held beliefs and values concerning the nature of psychotherapy and of schizophrenia. The paradoxes result in stress and resistance to learning new approaches and must be clarified and resolved for training to proceed successfully. The authors examine the origins of the paradoxes and the reactions of residents to each, and describe how the supervisory relationships of the training setting can be used to resolve them.

Adaptation, Psychological↗
PubMed1984

Inhibition of collagen fibril formation in vitro and subsequent cross-linking by glucose.

Glucose inhibits collagen fibril formation in vitro. A linear dose response was observed, with half-maximum inhibition of fibril formation occurring at 50 mM glucose. Nonfibrillar collagen cannot be cross-linked by lysyl oxidase, an enzyme that catalyzes the initial cross-linking reaction. The degree of decreased fibril formation correlated with the loss of ability of the collagen to serve as a substrate for lysyl oxidase. Collagen that is not cross-linked is unstable and more susceptible to collagenolytic attack. Interference with collagen cross-linking and more rapid degradation may explain the decreased amounts of interstitial collagen and the poor healing of wounds associated with diabetes mellitus.

Animals↗
PubMed1984

Hydrocortisone stimulates fibronectin synthesis in cultured fibroblasts.

The effect of hydrocortisone on fibronectin synthesis was investigated in cultured skin fibroblasts. Confluent cells were treated with hydrocortisone (10(-7) M to 10(-5) M) for 2 days and labeled with [3H]proline for 24 h. Fibronectin levels in both the culture medium and the cell layer were studied by gelatin-Sepharose affinity chromatography and SDS-polyacrylamide gel electrophoresis. In control cultures of human fetal skin fibroblasts, fibronectin constituted 8% of the total labeled proteins in the medium. The proportion of fibronectin increased to 13.1% at 10(-7) M hydrocortisone, 15.5% at 10(-6) M and to 19.4% at 10(-5) M. The proportion of fibronectin associated with the cell layer remained at 2-3% of total [3H]proline-labeled proteins and did not increase with hydrocortisone exposure. The stimulating effect of hydrocortisone on medium fibronectin was also demonstrated in cultured human newborn foreskin fibroblasts and in rabbit skin fibroblasts.

Cell Division↗
PubMed1984

A Canadian collaborative study of mosaicism in amniotic fluid cell cultures.

Data on chromosomal mosaicism was collected retrospectively on 12 386 amniotic fluid samples cultured over a 10 year period in 14 Canadian centres. Level I mosaicism (a single abnormal cell--excluding single cell monosomy) was encountered in 863 cases (7.1 per cent). Level II mosaicism (multiple cells with the same abnormality in a single flask or colony) was encountered in 138 cases (1.1 per cent). Level III mosaicism (multiple cells distributed over multiple flasks or colonies) was encountered in 34 cases (0.3 per cent). Analysis of the details of these cases allowed five major conclusions to be drawn: (1) Single cell abnormalities should not be taken as an indication of true fetal mosaicism. Only rarely will this interpretation prove to be incorrect. (2) Mosaicism involving multiple cells confined to a single flask should not be regarded as an indication of true fetal mosaicism. Only occasionally will this interpretation prove to be incorrect. (3) Mosaicism involving multiple cells distributed over more than one flask should be regarded as a strong indication of true fetal mosaicism. Sixty per cent will be confirmed by karyotype analysis of the fetus or infant. (4) Mosaicism of the XX/XY type is usually due to maternal cell contamination. Occasionally it can be a female fetus with XY cells from an unknown source. (5) The in situ or colony method of chromosome analysis has no clear advantage over the flask method for either the detection of true fetal mosaicism or for the ability to distinguish true mosaics from false positives.

Amniocentesis↗
PubMed1984

Collagen in the egg shell membranes of the hen.

Collagen-like proteins have been found in the egg shell membranes of the hen. Materials similar to types I and V collagens were detected in each of the two layers of this membrane, the thick outer membrane and the thin inner membrane. Collagen was extracted by acid-pepsin digestion and isolated by differential salt precipitation. Identification of type-specific collagen-like material was established by coelectrophoresis on SDS-polyacrylamide gels using known collagen standards. These bands were susceptible to digestion by bacterial collagenase. From differential staining of the gels it was estimated that the ratio of collagen types I:V was approximately 100:1. Further confirmation of these biochemical results was obtained with immunofluorescence microscopy using type-specific antisera against chicken types I and V collagen with the indirect sandwich technique. Both the inner and outer shell membranes contained the two types of collagen. Within each membrane, the large, coarse 2.5-micron fibers contained predominantly type I collagen-like material, while type V collagen was mainly associated with the delicate narrower fibers of approximately 0.6-micron diameter. These tended to be concentrated in the inner membrane. At the electron microscopic level, both types of fibers were coated with glycoproteins that stained positively with ruthenium red. The deposition of these collagen-like substances by the hen oviduct on to the surface of the developing egg is an additional example of interstitial-type collagen synthesis and secretion by epithelial rather than by mesenchymal cells.

Animals↗
PubMed1984

Intensive cytosine arabinoside therapy in small cell carcinoma of the lung.

Cytosine arabinoside (Ara-C) 100 mg/m2/d was given by continuous infusion to patients with small cell carcinoma of the lung in two simultaneous studies. In a first study, 10 patients who had failed prior therapy were treated with Ara-C alone. No responses were seen in these heavily pretreated patients and toxicity was severe. In a second study, Ara-C was added to the known active combination of cyclophosphamide, adriamycin, and vincristine (CAV) in 25 patients with extensive-stage small cell carcinoma with no prior treatment. Despite a clinical response rate of 52% (28% complete remissions, 24% partial remissions), the median survival was 169 days. This aggressive therapy approach produced substantial toxicity and no therapeutic benefit over previous regimens. Continuous infusion Ara-C (100 mg/m2/d X 3 days) used alone, or combined with CAV is not a useful agent for cell carcinoma of the lung.

Aged↗
PubMed1984

A rapid sensitive assay for the quantitation of elastin.

A rapid, sensitive and direct assay was developed for the quantitation of elastin using reverse phase high performance liquid chromatography. The method is based on the separation of the alkaline hydrolysis-resistant dipeptide valyl-proline, a dipeptide found in high concentrations in elastin. The methodology is applicable to unlabelled elastin samples in the range of 10-100 micrograms utilizing fluorescamine detection and to hot alkali insoluble as well as soluble forms of elastin. Increased sensitivity was achieved by the use of in vitro radiolabelling of elastin with [3H]proline. This was useful for following synthesis of elastin in cultured cells. Since this technique is not dependent on detection of the elastin-specific crosslink groups, desmosine and isodesmosine, precursor forms of elastin can be measured as well as other forms of elastin deficient in cross-linking. The same chromatographic procedure however, is able to detect these desmosine and isodesmosine crosslinks. Therefore, in cell cultures under the proper radiolabelling conditions, biosynthesis and cross-linking of elastin can be followed simultaneously in a single chromatographic procedure.

Animals↗
PubMed1984

ECG abnormalities in polymyositis.

Electrocardiographic abnormalities were found in 25 (32.5%) of 77 patients with polymyositis. Left anterior hemiblock (13.0%) and right bundle-branch block (9.1%) were the most common abnormalities. No association could be found between these defects and clinical activity of polymyositis, severity of duration of disease, or degree of creatine kinase level elevation. Similarly, there was no association with age or the presence of certain clinical conditions such as rash or arthritis. In only two patients, both children, did an ECG abnormality improve with corticosteroid therapy. Three patients with heart block died suddenly. This study points up the need for continual close observation of patients with inflammatory muscle disease, even after apparent remission.

Adolescent↗
PubMed1984

The matrix of human breast tumor cells is mitogenic for fibroblasts.

The basis of the scirrhous reaction to human breast carcinoma was investigated. When normal human skin fibroblasts were plated on the preformed extracellular matrix of human breast tumor cells, a remarkable series of changes was observed. The matrix of the tumor cells was mitogenic for the fibroblasts. An increased growth rate and a fourfold increase in cell density was observed. There was also a change in cell morphology and in the pattern in which the cells grew, with an apparent loss of contact inhibition. The spindle-shaped fibroblasts became more elliptical and grew in a series of whorls and dense ridges with spaces between them. These observations were made with the use of newborn foreskin fibroblasts and the matrix of an established line of human breast cancer cells, ZR75-1. No such effect was seen when fibroblasts were plated on their own preformed matrix, on the matrixes of other cell types, on various type-specific collagen gels, or on a combination of collagen and fibronectin or when fibroblasts were grown in media conditioned by the ZR75-1 cells. A floating tumor cell matrix added to the cell media also did not provide the mitogenic stimulus. Apparently, fibroblasts required direct contact with the tumor cell matrix for the mitogenic response to occur. In vivo, the matrix of breast tumor cells may modulate the growth and the morphology of host stromal cells. Collagen is a major synthetic product of fibroblasts. The stimulation of stromal cells to proliferate by adjacent breast tumor matrix may be the basis of the desmoplastic reaction, the intense fibrotic response associated with human breast cancer.

Breast Neoplasms↗
PubMed1983

"Baltic" myoclonus epilepsy: hereditary disorder of childhood made worse by phenytoin.

A survey of 15 families in the USA with Baltic myoclonus epilepsy showed that the 27 individuals who were affected had the following clinical picture from about the age of 10: photosensitive, occasionally violent, myoclonus, usually worse upon waking; generalised tonic-clonic seizures, sometimes associated with absence attacks; and light-sensitive, generally synchronous, spike-and-wave discharges on EEG that preceded clinical manifestations. Necropsy revealed marked loss of Purkinje cells of the cerebellum, but no inclusion bodies. Since the disease was confined to sibs and consanguinity was present in two families, autosomal recessive inheritance is probable. The disease progressed more rapidly in these families than it did in the early cases, seen in the Baltic region. This difference could be due to a toxic effect of phenytoin because phenytoin given alone or with other antiepileptic drugs was associated with progressive motor and intellectual deterioration, marked ataxia, and even death. Treatment with valproic acid, and the concomitant reduction or elimination of phenytoin, has been associated with marked improvement in at least 8 patients. Baltic myoclonus epilepsy must be distinguished from Lafora body disease, which is invariably fatal and discernible on clinical grounds.

Adolescent↗
PubMed1983

Individual cells in the nucleus basalis--diagonal band complex have restricted axonal projections to the cerebral cortex in the rat.

Cells in the nucleus basalis--diagonal band complex provide a largely cholinergic projection to all parts of the telencephalon, including the olfactory system, amygdala, hippocampus and neocortex. Experiments using fluorescent dyes as double retrograde axonal tracers indicate that although the projection as a whole is very widespread, the projection of individual cells is limited to a very restricted area within the cortex, not more than 1-1.5 mm in diameter.

Animals↗
PubMed1983

Neutrophilic dermatosis of myeloproliferative disorders. Atypical forms of pyoderma gangrenosum and Sweet's syndrome associated with myeloproliferative disorders.

Atypical forms of pyoderma gangrenosum (PG) and Sweet's syndrome (SS) (acute febrile neutrophilic dermatosis) have been separately reported in association with various forms of leukemia over the past decade. A case in which both atypical bullous PG and atypical SS occurred in a patient with myeloid metaplasia is presented, and the literature is reviewed concerning the association of these dermatoses with neoplasias of myeloid origin. The current case and review support the thesis that these dermatoses, when associated with myeloproliferative disorders, represent points on a continuum of noninfectious, nonmetastatic, inflammatory neutrophilic dermatoses that may occur in patients with derangements in myeloid cell proliferation.

Adult↗
PubMed1983

Modulation of collagen synthesis by a growth factor and by the extracellular matrix: comparison of cellular response to two different stimuli.

Cultured bovine corneal endothelial cells can be grown in three ways: on plastic, on plastic with fibroblast growth factor present in the media, and on their own preformed extracellular matrix. On plastic alone, cells grow in a disorderly fashion and secrete matrix on all cell surfaces. Cells grown on plastic with growth factor or on a matrix, at confluence, have matrix deposition only on the basal surface of the cells and an orderly contact-inhibited pattern of growth. This correlates with the polarity they demonstrate histologically. This cell-matrix pattern resembles the pattern observed in vivo. Both the soluble growth factor and the extracellular matrix are able to modulate the pattern of collagen synthesis and deposition by cells, but they do so in two entirely different ways. In cells grown on the extracellular matrix, total collagen synthesis is lower but more efficient. Collagen is deposited primarily into the cell layer even at the early sparse stage of culture. In cells grown on plastic with growth factor in the media, collagen is initially secreted into the media and does not become incorporated into the matrix. The deposition of collagen on the basal surface of cell occurs only late in the culture, and is achieved by increments in a stepwise manner. The in vivo-like pattern is not manifest until confluence has been reached. Thus, the extracellular matrix functions not only as a structural support, but is also instructional to the cells plated on it. In this case, the matrix regulates the level of collagen synthesis in the cells and modulates the pattern of collagen deposition. Soluble growth factors may act in part by enhancing a cell's ability to elaborate an appropriate matrix pattern necessary for the cell's own growth and accurate function.

Animals↗
PubMed1982

Comparison of collagen types in adult and fetal bovine corneas.

The collagen types in the fetal and adult bovine corneal layers were compared. The cornea was separated into epithelial, endothelial, and stromal layers. Of the interstitial collagens, type I was the predominant in all layers of both fetal and adult corneas. Only type I of the interstitial collagens was found in the three layers of the adult cornea. Type I collagen was also found in all layers of the fetal cornea together with a minute amount, less than 2%, of type III collagen. The type III collagen could only be detected by cyanogen bromide peptide gel maps and was not apparent by gel electrophoresis of intact alpha chains. Of the noninterstitial collagens, type V was present throughout the three corneal layers. Type IV, basement membrane-specific collagen was found only in the endothelial and epithelial layers, which contain Descemet's and Bowman's membrane, respectively. The transient presence of type III collagen reflects an embryonic stage of corneal development.

Animals↗
PubMed1982

Beneficial hemodynamic effects of intravenous diazoxide in refractory congestive heart failure.

Despite the growing popularity of vasodilator therapy for acute and chronic congestive heart failure (CHF), no single agent has been uniformly effective and well tolerated. Therefore, we investigated the acute hemodynamic response to diazoxide, a potent and long-acting arteriolar dilator, in nine patients with severe CHF refractory to conventional treatment and, in seven of nine, other vasodilators. Diazoxide was administered intravenously in successive 300 mg infusions, each over 10 minutes, until a satisfactory response in cardiac and output occurred or a fall in arterial blood pressure or increase in heart rate was noted. The mean dose of diazoxide was 670 mg (range 450 to 900 mg). Systemic vascular resistance fell immediately, by a maximum of 44%. Arterial pressure was not changed significantly, but cardiac and stroke volume indices rose by 64% and 49%, respectively, from 2.0 +/- 0.5 to 3.3 +/- 0.6 L/min/m2 and from 24 +/- 10 to 36 +/- 9 ml/m2 (each p less than 0.001). Pulmonary capillary wedge pressure declined more gradually, by a mean of 8 mm at 4 and 6 hours after drug infusion. This hemodynamic improvement was sustained for a mean of 9.7 hours (range 6 to 12 hours). Our findings indicate that intravenous diazoxide may be useful in the management of acute heart failure and that a trial of oral diazoxide in chronic normotensive CHF is warranted.

Adult↗