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Biomedical subjects

R Katz

Publications and source records attributed to R Katz.

At least 19 recordsLinked to original sources
PubMed1992

Characterization of mouse thrombospondin 2 sequence and expression during cell growth and development.

Thrombospondin (TSP) is an extracellular matrix glycoprotein whose expression has been associated with a variety of cellular processes including growth and embryogenesis. The recent discovery of the existence of a second mouse TSP gene necessitates careful examination of the discrete biochemical and functional properties associated with each molecule. In this report, the primary structures of human TSP, mouse TSP1 (mTSP1), mouse TSP2 (mTSP2), and chicken TSP are compared; and the expression of mTSP1 and mTSP2 during embryogenesis and growth factor-mediated cell proliferation is examined. The cloning and sequencing of the entire coding regions of mTSP1 and mTSP2 revealed considerable conservation of residues critical for TSP structure and function; these data suggest that TSP2 is capable of trimer formation and many of the same cell-surface and ligand interactions that mediate TSP function. Comparison of the various TSP sequences also allowed the assignment based on sequence homology of previously reported human TSP as TSP1 and chicken TSP as TSP2. mTSP2, like mTSP1, was shown to be a primary response gene when quiescent Swiss 3T3 cells were stimulated with serum, platelet-derived growth factor BB, basic fibroblast growth factor, or interleukin-1 beta. Interestingly, TSP1 and TSP2 exhibited markedly different tissue- and stage-specific patterns of mRNA expression during mouse embryogenesis, implying that the two TSP molecules possess discrete functional properties important for development. Additionally, the TSP genes (Thbs1 and Thbs2) were mapped to single loci on mouse chromosomes 2 and 17, respectively.

3T3 Cells↗
PubMed1992

Distribution of heteronymous Ia facilitation and recurrent inhibition in the human deltoid motor nucleus.

Distribution of heteronymous Ia facilitation and of heteronymous recurrent inhibition in motoneurones innervating the anterior part of the deltoid muscle were investigated in normal human subjects following electrical stimulation of the nerves innervating the main muscles of the upper limb. Activation of group I afferents originating from deltoid, biceps, triceps and extensor carpi radialis (ECR) muscles resulted in an early increase in firing probability of voluntarily activated motor units belonging to the anterior part of the deltoid muscle whereas activation of motor axons supplying deltoid, triceps, ECR and flexor carpi radialis (FCR) muscles resulted in an early and long-lasting decrease in firing probability. No effect was seen following activation of group I afferents and motor axons contained in the ulnar nerve. The characteristics of the early facilitation suggest that it is at least partly due to heteronymous Ia monosynaptic connections while these of the long-lasting inhibition suggest that it is at least partly due to heteronymous recurrent inhibition. Their patterns of distribution are discussed with regards to the functional role of the human deltoid.

Adult↗
PubMed1992

Pattern of projections of group I afferents from elbow muscles to motoneurones supplying wrist muscles in man.

The pattern of projections of low threshold afferents from triceps and biceps brachii muscles onto motoneurones innervating muscles acting at the wrist was assessed by a reflex and a poststimulus time histogram (psth) technique. Activation of low-threshold afferents originating from elbow flexors or extensors resulted in an early, short-lasting inhibition of wrist flexor motoneurones (flexor carpi radialis, flexor carpi ulnaris). An inhibition was also found in the extensor carpi radialis (ECR) motoneurones after stimulation of low-threshold afferents from triceps. Evidence is presented that Ia fibres contribute to these effects. The inhibitory effects were found in all subjects, but they were constant in only 57% of the reflex experimental sessions and in 25% of the explored motor units. Stimulation of biceps low-threshold afferents was always ineffective on ECR motoneurones. No early facilitation was ever seen in motor nuclei innervating wrist muscles following stimulation of low threshold afferents from biceps and triceps. The pattern of transjoint projections of group I afferents from proximal to distal muscles and from distal to proximal ones (Cavallari and Katz 1989) is discussed in relation to that described in the cat forelimb.

Adult↗
PubMed1992

Cognitive and life stress predictors of relapse in remitted unipolar depressed patients: test of the congruency hypothesis.

Remitted depressed subjects (N = 59) were followed longitudinally to determine whether dependent or self-critical persons are more vulnerable to relapse after exposure to life events that have a bearing on interpersonal or achievement concerns. Regression analyses indicated that congruency effects, as measured by the occurrence of achievement-related adversity in the lives of self-critical subjects, accounted for a significant increment in relapse variance over each variable entered singly. When data from the 2 months just before relapse were analyzed, some evidence of congruency effects in dependent subjects experiencing interpersonal-related adversity was obtained. These findings highlight the dimensional qualities of life even impact and call for greater differentiation in modeling the activation of a diathesis and precipitation of depression after life stress.

Adaptation, Psychological↗
PubMed1992

Chronic maxillary sinusitis associated with the mushroom Schizophyllum commune in a patient with AIDS.

Invasive infection with fungi of the Basidiomycota (rusts, smuts, toadstools, mushrooms, and puffballs) is extremely rare. We report such an infection in a patient with human immunodeficiency virus disease who presented with chronic maxillary sinusitis associated with the mushroom Schizophyllum commune. The organism was isolated from the surgical drainage material, and septate hyphae were seen invading the maxillary submucosa. The limited literature on this subject is reviewed.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Clomipramine hydrochloride in childhood and adolescent obsessive-compulsive disorder--a multicenter trial.

Children and adolescents with obsessive compulsive disorder were studied in an 8-week, multicenter, double-blind, parallel groups trial of clomipramine hydrochloride (CMI) versus placebo. Efficacy assessments included the child version of the Yale-Brown Obsessive Compulsive Scale and the National Institute of Mental Health Global rating scale. At the end of 8 weeks, CMI-treated patients showed a mean reduction in Yale-Brown Obsessive Compulsive Scale score of 37% compared to 8% in the placebo group. Side effects were typical of tricyclic antidepressants. In a 1-year open label treatment, CMI continued to be effective and well tolerated.

Adolescent↗
PubMed1992

Use of granulocyte colony-stimulating factor in the treatment of pancytopenia secondary to colchicine overdose.

OBJECTIVE: To report a case of pancytopenia following colchicine overdose and to discuss the use of granulocyte colony-stimulating factor (G-CSF) for treating this severe complication. CASE SUMMARY: A 19-year-old man developed pancytopenia four days after ingestion of approximately 50-60 0.6-mg colchicine tablets in a suicide attempt. His pancytopenia resolved after subcutaneous administration of one 300-micrograms dose of G-CSF. The patient recovered from his other multiorgan disturbances during his hospitalization and was discharged from the hospital with elevated liver enzyme concentrations. CONCLUSIONS: Colchicine overdose is rare, but can be fatal. The use of G-CSF appears to be beneficial in alleviating bone marrow depression in colchicine overdose situations.

Adult↗
PubMed1992

Abnormalities of response processing in a chronic psychiatric group. A possible predictor of failure in rehabilitation programmes?

This study attempted to identify, in a mixed group of chronic patients, a specific measure of cognitive processing that may be of use in predicting dependence on psychiatric care. The measures investigated are derived from reaction-time tasks. Difficulties of response processing seem to account for the largest amount of variance in current service use. When compared with other variables shown to have some predictive power (e.g. social behaviour, symptoms and chronicity), the reaction time measures fare well. Functions derived from discriminant analyses using all the variables correctly classified 90% of those requiring day care and 95% of those requiring night care. Stepwise methods produced lower classification rates but always included reaction-time measures in the predictor set. Patients with continuing cognitive difficulties are likely to remain in more supportive psychiatric settings despite rigorous rehabilitation procedures.

Chronic Disease↗
PubMed1992

Cluster management.

Cluster management is a management model that fosters decentralization of management, develops leadership potential of staff, and creates ownership of unit-based goals. Unlike shared governance models, there is no formal structure created by committees and it is less threatening for managers. There are two parts to the cluster management model. One is the formation of cluster groups, consisting of all staff and facilitated by a cluster leader. The cluster groups function for communication and problem-solving. The second part of the cluster management model is the creation of task forces. These task forces are designed to work on short-term goals, usually in response to solving one of the unit's goals. Sometimes the task forces are used for quality improvement or system problems. Clusters are groups of not more than five or six staff members, facilitated by a cluster leader. A cluster is made up of individuals who work the same shift. For example, people with job titles who work days would be in a cluster. There would be registered nurses, licensed practical nurses, nursing assistants, and unit clerks in the cluster. The cluster leader is chosen by the manager based on certain criteria and is trained for this specialized role. The concept of cluster management, criteria for choosing leaders, training for leaders, using cluster groups to solve quality improvement issues, and the learning process necessary for manager support are described.

Communication↗
PubMed1992

Biochemical clues to a fibromyalgia-depression link: imipramine binding in patients with fibromyalgia or depression and in healthy controls.

Both fibromyalgia and depression may be related to disturbed serotonin metabolism, and an association between the 2 disorders has been postulated. We measured 3H-imipramine binding (IB), a biochemical indicator of serotonin uptake, pretreatment, in 10 nondepressed women with fibromyalgia, 14 subjects with major depression, and 10 volunteer controls. Our objective was to determine if IB in the 2 patient groups differed and in the same direction from the control values. Compared with depressed women, IB was significantly lower both in the women with fibromyalgia and in the men with depression. However, no women with fibromyalgia or men with depression had IB levels that were significantly different from control women and men. There was a trend for higher IB levels in depressed compared to control women.

Adult↗
PubMed1992

Immediate and delayed type hypersensitivity to malathion.

Between December 1989 and June 1990, 1,874 reports of alleged malathion application related illness from repeated spraying of a mixture of malathion corn syrup bait to eradicate a Mediterranean fruit fly infestation in Southern California were received by the Toxics Epidemiology Program of Los Angeles County. Among these complaints were 47 reports of urticaria, 38 reports of angioedema and 213 reports of a nonspecific skin rash. In order to determine whether these alleged skin reactions were the result of an immediate or delayed type of hypersensitivity reaction to malathion or to the corn syrup bait we studied ten subjects referred for testing by the local health department. All ten subjects had no reaction on patch testing. One child exhibited a positive reaction to the bait and one child had irritant reactions to malathion and to the bait. This study documented one case of a possible immediate IgE reaction to malathion bait. Due to the low participation rates in this study, no specific conclusions concerning the rate of sensitivity in the population can be drawn, although it appears that such reactions are uncommon.

Adult↗
PubMed1992

Decreased interleukin 1 activity released from circulating monocytes of patients with familial Mediterranean fever during in vitro stimulation by lipopolysaccharide.

Familial Mediterranean fever (FMF) is an inherited disorder of unknown etiology characterized by recurrent episodes of serous membrane inflammation. Interleukin 1 (IL-1) is a mediator of inflammatory processes. We hypothesized that IL-1 may play a role in acute attacks of FMF. Thus we tested IL-1 production by monocytes derived from patients with FMF. Nine patients were tested during acute attacks and 9 were asymptomatic when tested. Monocytes derived from peripheral blood of patients and controls were stimulated with lipopolysaccharide (LPS) and IL-1 activity in the supernatant was tested using a T helper cell line (D10-4G.1). IL-1 secretion during acute attacks was decreased whereas IL-1 production in asymptomatic patients was comparable to healthy controls. Followup of symptomatic patients during the recovery period revealed normalization of IL-1 secretion. Addition of indomethacin (prostaglandin E2 inhibitor) to LPS stimulated monocytes did not change IL-1 activity in patients or healthy controls. We conclude that in vitro IL-1 activity in patients with FMF is associated with the intensity of the inflammatory process.

Adolescent↗
PubMed1992

Coronal computerized tomography and cerebrospinal fluid rhinorrhea.

Accurate diagnosis of cerebrospinal fluid rhinorrhea (CSFR) is a challenge for physicians caring for patients with traumatic brain injury. Failure to recognize this condition may result in significant medical complications and prolong hospitalization. Two male patients who developed CSFR within 2 months of severe head injury are described. A clear nasal discharge was noted on examination approximately 30 and 35 days after head injury in both patients and a CSF fistula was suspected. High-resolution computerized tomography (CT) with coronal sections confirmed the diagnosis. Both patients underwent neurosurgical intervention to repair the fistulous tracts without recurrence. Sequelae of CSFR in one case included meningitis and pneumocephalus. Literature review shows water-soluble contrast CT cisternography (CTC) to be the gold standard for the diagnosis of CSFR. However, other diagnostic studies may include immunoelectrophoresis of rhinorrhea, use of isotope tracers, plain x-rays, tomography, and noncontrast high-resolution CT. More invasive studies like CTC are often recommended in the diagnosis of this condition, but are more costly, painful, and carry a small risk of infection. Our two case reports emphasize that high-resolution CT may be performed as a primary noninvasive diagnostic procedure before more invasive studies, and the results obtained may be sufficient for therapeutic planning.

Adult↗
PubMed1991

Stimulation of B-cells via the membrane immunoglobulin receptor or with phorbol myristate 13-acetate induces tyrosine phosphorylation and activation of a 42-kDa microtubule-associated protein-2 kinase.

Engagement of membrane IgM on a number of human and murine B-cell lines induced activation of a Mn(2+)-preferring serine/threonine kinase that phosphorylated microtubule-associated protein-2 (MAP-2) in vitro. B-cell MAP-2 kinase (MAP-2K) activity could be fractionated into two peaks by sequential DEAE and hydrophobic chromatography. Although peak I included two tyrosine phosphoproteins of molecular mass 36 and 38 kDa, peak II showed a single 42-kDa tyrosine phosphoprotein (pp42). Since all kinase activity could be removed from peak II material over an antiphosphotyrosine immune affinity column, it suggests that pp42 is identical with lymphoid MAP-2K. Although peak I activity showed a similarity to peak II with regard to its preference for Mn2+, sensitivity to phosphatase exposure, and resistance to a range of common serine kinase inhibitors, it is not clear whether these activities are related. MAP-2 kinase activity could also be induced by treatment with the phorbol ester, phorbol myristate 13-acetate, suggesting that protein kinase C may also be involved with MAP-2K regulation. Although MAP-2K activity reached a peak response within minutes of receptor ligation, there were differences in the rates of dephosphorylation of pp42 and decline of MAP-2K activity in different B-cell lines. The tyrosine phosphatase inhibitor, vanadate, transformed a rapidly reversible MAP-2K response in BAL 17.2 cells into a sustained state of activation that resembled the kinetics of activation in WEHI-231 cells. The latter finding implies involvement of a tyrosine phosphatase, which opposes the effect of an inducing tyrosine kinase.

Animals↗
PubMed1991

A second, expressed thrombospondin gene (Thbs2) exists in the mouse genome.

The diverse and occasionally conflicting properties described for the extracellular, cell surface-associated protein thrombospondin (TSP) have raised the possibility that functionally distinct forms of the protein exist in the same organism. We have isolated and characterized a partial cDNA clone for mouse TSP that is clearly homologous to, but distinct from, the coding sequence for mouse TSP deduced from a mouse genomic clone (Bornstein, P., Alfi, D., Devarayalu, L., Framson, P., and Li, P. (1990) J. Biol. Chem. 265, 16691-16698). This second TSP, which we term thrombospondin 2, is the product of a separate gene (Thbs2) and is expressed in a variety of mouse tissues in a pattern that differs from that for TSP1. Based on their translated amino acid sequences, it seems likely that TSP1 and TSP2 will be found to have both common and unique properties and that the functional consequences of TSP production will reflect the ratio of the levels of these two related proteins.

Amino Acid Sequence↗
PubMed1991

Evidence for involvement of glycoprotein-CD45 phosphatase in reversing glycoprotein-CD3-induced microtubule-associated protein-2 kinase activity in Jurkat T-cells.

Ligation of CD3/TCR on T-cells induces transient activation of lymphoid MAP-2 kinase (MAP-2K), a 43 kDa serine kinase which itself is a substrate of an unidentified tyrosine kinase (pp43). The reversibility of the MAP-2K response agrees with removal of tyrosine phosphates from pp43. Since both activity as well as tyrosine phosphorylation of MAP-2K could be prolonged by Na3VO4, a phosphotyrosine phosphatase inhibitor, we studied the effect of the common CD45 isoform, which is a member of the CD45 phosphatase family, on MAP-2K activity in vivo and in vitro. We demonstrate the ability of purified CD45 phosphatase to remove tyrosine phosphates from partially purified lymphoid MAP-2K. Utilizing the approach of heterologous receptor aggregation, we also showed that CD45 could inhibit the induction of MAP-2K activity in intact Jurkat cells during CD3 or CD3 + CD4 stimulation. We therefore suggest that this phosphatase may control the activity of lymphoid MAP-2K in vivo.

Antigens, CD↗
PubMed1991

Fine-needle aspiration evaluation of lymphoproliferative lesions in human immunodeficiency virus-positive patients. A multiparameter approach.

Forty-six fine-needle aspirates of lymphoproliferative lesions from 31 human immunodeficiency virus (HIV)-positive patients were reviewed using cytomorphologic, immunocytochemical, flow cytometric (FCM), cytogenetic, and molecular studies. There were 29 lymphomas (15 small non-cleaved cell [SNCL], 11 large cell [LCL], one small lymphocytic, and two Hodgkin's), 14 reactive hyperplasias, and three "atypical lymphoid proliferations." The reactive hyperplasias were characteristically polymorphic and polyclonal lymphoid populations; six of seven were diploid on FCM, the seventh was hypodiploid. Higher proliferative indices (mean, 11.6%) and higher RNA indices (mean, 1.2) characterized this subgroup compared with published reactive lymphoid hyperplasias from patients without HIV positivity. Aspirates of SNCL showed monotonous populations of intermediate-sized cells except in one patient where a giant cell syncytial variant occurred. Nine of 13 SNCL aspirates showed light chain restriction. JH rearrangement revealed B-cell lineage in one aspirate in which immunocytochemical study was negative for Kappa, lambda, B1, and Leu-4. Nine of 12 SNCL were diploid; the mean proliferative index was 25.6% and the mean RNA index 2.3. Chromosomal translocations involving the c-myc locus were demonstrated in five of seven SNCL aspirates karyotyped. Five of eight LCL showed light chain restriction the remaining three showed null cell phenotype. Large cell lymphomas were diploid on tetraploid with the mean proliferative index of 22.0% and mean RNA index of 2.2. One of two LCL aspirates karyotyped demonstrated c-myc translocation. Despite the multiparameter approach, a definitive diagnosis could not be reached in three aspirates.

Adult↗