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Biomedical subjects

G Katz

Publications and source records attributed to G Katz.

At least 19 recordsLinked to original sources
PubMed2001

Recognition of HLA-Cw4 but not HLA-Cw6 by the NK cell receptor killer cell Ig-like receptor two-domain short tail number 4.

NK cells are cytotoxic to virus-infected and tumor cells that have lost surface expression of class I MHC proteins. Target cell expression of class I MHC proteins inhibits NK cytotoxicity through binding to inhibitory NK receptors. In contrast, a similar family of activating NK receptors, characterized by the presence of a charged residue in their transmembrane portion and a truncated cytoplasmic tail, augment lysis by NK cells when ligated by an appropriate class I MHC protein. However, the class I MHC specificity of many of these activating NK receptors is still unknown. Here, we show enhanced lysis of HLA-Cw4 but not HLA-Cw6-expressing cells, by a subset of NK clones. This subset may express killer cell Ig-like receptor two-domain short tail number 4 (KIR2DS4), as suggested by staining with various mAb. It is still possible, however, that these clones may express receptors other than KIR2DS4 that might recognize HLA-Cw4. Binding of KIR2DS4-Ig fusion protein to cells expressing HLA-Cw4 but not to those expressing HLA-Cw6 was also observed. The binding of KIR2DS4-Ig to HLA-Cw4 is weaker than that of killer cell Ig-like receptor two-domain long tail number 1 (KIR2DL1)-Ig fusion protein; however, such weak recognition is capable of inhibiting lysis by an NK transfectant expressing a chimeric molecule of KIR2DS4 fused to the transmembrane and cytoplasmic portion of KIR2DL1. Residue alpha14 is shown to be important in the KIR2DS4 binding to HLA-Cw4. Implications of the role of the activating NK receptors in immunosurveillance are discussed.

Adjuvants, Immunologic↗
PubMed2001

Extracorporeal shock wave lithotripsy is highly effective for ureteral calculi in children.

PURPOSE: Treatment of ureteral calculi in the pediatric population represents a unique challenge. Extracorporeal shock wave lithotripsy (ESWL*) and ureteroscopy have been advocated for the treatment of such stones. We present our experience with ESWL monotherapy for ureteral stones in children in the last decade. MATERIALS AND METHODS: Between 1989 and 1999 we treated 21 boys and 17 girls with a mean age of 8 years (range 8 months to 14 years) with ureteral stones at our institution. Records were reviewed and analyzed for presentation, metabolic and anatomical anomalies, stone size and location, outcome and complications. Average stone size was 9.5 x 6.5 mm. (range 3 to 32). Stones were in the upper ureter in 17 cases, mid ureter in 2 and lower ureter in 19. All patients underwent ESWL with a Dornier HM3 lithotriptor under general anesthesia. Nephrostomies were placed in an anuric infant with bilateral ureteral obstruction and in 2 patients with nonfunctioning kidneys (4 renal units). Ureteral catheters were used in 15 patients for better identification and localization of the stone during ESWL. The catheters were removed immediately postoperatively. RESULTS: Of the patients 31 (81.5%) were free of stones after 1 session of ESWL, 5 (13.1%) after 2 and 1 after 3. One patient underwent ureteroscopy for residual fragments after 2 ESWL sessions. The stone-free rate following 1 ESWL session was 100% for ureteral calculi 10 mm. or smaller regardless of location. Of the 12 patients with stones larger than 10 mm. 8 (67%) were free of stones following 1 ESWL session. The overall success rate of ESWL was 97.3%. No child had postoperative urinary infection or ureteral obstruction. CONCLUSIONS: ESWL is an efficient and safe modality for the treatment of pediatric ureteral stones.

Adolescent↗
PubMed2001

Use of a modified American Urological Association Symptom Score for the evaluation of the quality of life of patients with prostate cancer.

OBJECTIVES: To present our experience with the clinical use of a modified American Urological Association Symptom Score (AUASS) and a quality-of-life (QOL) questionnaire in obtaining clinically available information and to investigate whether a relatively short questionnaire, administered in the clinic, can help in identifying symptoms and QOL issues associated with various types of definitive treatments (DTs) for prostate cancer (PCa) and its impact on patients' QOL. METHODS: The AUASS was modified to contain questions on continence and was combined with a short QOL questionnaire. It was administered to control groups and all patients with PCa during their clinic visit. The responses were analyzed and correlated with the DT of PCa. RESULTS: The questionnaire was administered 846 times to 375 patients with PCa and to 170 controls during clinic visits. We found that patients on watchful waiting had symptom scores and QOL responses similar to controls and that DT was associated with worse scores and a reduced QOL. DT with continence was associated with a better QOL than DT with incontinence. Incontinence of either urine or stool, among DT patients, had similar adverse impact on QOL, compared with continent DT patients. CONCLUSIONS: The questionnaire, administered in a clinical setting, provides insight into the QOL and symptoms associated with interventions aimed at curing PCa. The use of such a questionnaire enhances the objective documentation of treatment outcomes of PCa and benefits the patients by increasing their opportunities to express their problems.

Case-Control Studies↗
PubMed2001

Psychiatric aspects of jet lag: review and hypothesis.

Jet lag is a travel-induced circadian rhythm phenomenon that afflicts healthy individuals following long- distance flights through several time zones. The typical jet-lag manifestations - insomnia during local sleep time, day fatigue, reduced concentration, irritability, and exhaustion with mild depression - are attributed to transient desynchronization in the circadian rhythm until the internal biological clock is rephased to the new environmental conditions. There is strong evidence relating affective disorders with circadian rhythm abnormalities. Less convincing suggestions relate jet lag to psychosis. It can be hypothesized that in predisposed individuals jet lag may play a role in triggering exacerbation or even de novo affective disorders. Furthermore, we propose the possibility that psychosis and even schizophrenia can be elicited by jet lag. This outlook gains its support from case studies and some common underlying phase-advanced biological denominators involved in both jet lag sufferers and psychotic patients.

Humans↗
PubMed2000

[Drug abuse among patients requiring psychiatric hospitalization].

We assessed the incidence of drug abuse among patients requiring psychiatric hospitalization, and characterized the population at risk. The data on drug abuse were obtained from self-reports and urine tests in 103 patients, aged 18-65, hospitalized in the Kfar Shaul Psychiatric Hospital (autumn 1998). There was close correspondence between the self-reports and the results obtained from urine tests. 1/3 admitted to having used illegal drugs and signs of drug abuse were found in about 1/4 of the urine tests. The most prevalent drugs were cannabis products (hashish and/or marijuana) and in 15 patients opiates. Drug users were younger than non-users. With regard to psychiatric symptomatology, fewer negative symptoms were recorded among cannabis abusers with schizophrenia, compared to schizophrenic patients with no history, past or present, of cannabis abuse. The present findings confirm the clinical impression that there has been an increase in drug abuse among mental patients, parallel to that found in society at large. Confirmatory surveys are necessary. Our findings clearly suggest that a change in attitude has occurred in Israel to what has been considered a marginal problem. Hospitalized mentally-ill patients, the younger in particular, should be considered at risk for drug abuse.

Adolescent↗
PubMed2000

[Jet lag causing or exacerbating psychiatric disorders].

Desynchronization of circadian rhythmicity resulting from rapid travel through at least 4 time zones leads to symptoms of jet lag syndrome. The most commonly experienced symptoms in normal individuals are sleep disorders, difficulties with concentrating, irritability, mild depression, fatigue, and gastrointestinal disturbances. There is strong evidence relating affective disorders to circadian rhythm abnormalities, such as occur in jet lag. Less convincing suggestions relate jet lag to psychosis. We presume, relying on the literature and our accumulated experience, that in predisposed individuals jet lag may play a role in triggering exacerbation of, or de novo affective disorders, as well as, though less convincing, schizophreniform psychosis or even schizophrenia. An illustrative case vignette exemplifies the possible relationship between jet lag following eastbound flight and psychotic manifestations.

Antipsychotic Agents↗
PubMed2000

Pure follicle-stimulating hormone as an adjuvant therapy for selected cases in male infertility during in-vitro fertilization is beneficial.

OBJECTIVES: Since research has demonstrated the possibility of hormonal therapy for male infertility, we conducted a study to analyze the efficacy of pure follicle-stimulating hormone (pFSH) treatment in patients with idiopathic, severe oligoteratoastheno-spermia (OTA) syndrome, or failed fertilization before referral to an intracytoplasmic sperm injection (ICSI) in an in-vitro fertilization (IVF) program. STUDY DESIGN: A retrospective, clinical study was carried out on 178 men with OTA syndrome. Group I comprised 76 patients selected for treatment with pFSH. Group II comprised 102 men who served as the controls. Pure FSH was administered intramuscularly to the patients in group I. Upon cessation of therapy, an IVF treatment cycle was carried out. RESULTS: After treatment with FSH, sperm motility was the only parameter which significantly improved in Group I (34% vs. 23%, and 15% vs. 24% in the subgroups of Group 1, respectively; P<0.05). In-vitro fertilization pregnancy rates were similar in both groups. The highest spontaneous pregnancy rates were achieved in FSH-treated, severe OTA patients. CONCLUSIONS: Patients with severe male factor infertility may benefit from pFSH in terms of sperm motility, fertilization by IVF and spontaneous pregnancy rates. Selection criteria for FSH treatment are proposed.

Adult↗
PubMed2000

Risperidone in treating behavioural disturbances of Prader-Willi syndrome.

OBJECTIVE: This paper reports the results of risperidone treatment in seven patients (six adults and one adolescent) diagnosed as suffering from Prader-Willi syndrome (PWS) accompanied by severe behavioural disturbances. Risperidone was chosen following the failure of these patients to respond to other acknowledged modes of treatment for the psychiatric manifestations of PWS. METHOD: This was a prospective open-label study. Measures of Clinical Global Impression Scale (CGIS), Retrospective Overt Aggression Scale (ROAS), Aggression Score (AS) and weight were obtained during two baseline visits and again following 37 weeks of treatment with risperidone. RESULTS: Low dosages (1-3 mg/day; 1.6 mg/day on average) of risperidone brought about notable clinical improvement with no apparent adverse side effects. All measures evaluated--general behaviour, CGIS, OAS and weight--reacted favourably to the treatment protocol. CONCLUSION: The preliminary results presented here suggest that risperidone is useful in treating PWS due to its positive effect on the disruptive behavioural symptoms that accompany it.

Adolescent↗
PubMed2000

Dynamics of charge transfer states on metal surfaces: the competition between reactivity and quenching.

The dynamics of excited states of adsorbates on surfaces caused by charge transfer is studied. Both negative and positive charge transfer processes are possible. In particular we are interested in positive charge transfer from a metal surface to molecular or atomic oxygen adsorbed on the surface. Once the negatively charged oxygen on the surface loses an electron it becomes chemically activated. The ability of this species to react depends on the quenching time or back transfer. The analysis of these processes is based on a set of diabatic potential energy surfaces each representing a different charged oxygen species. The dynamics is followed by solving the multichannel time-dependent Schrödinger equation or Liouville von Neumann equation. Due to the nonadiabatic character of these reactions large isotope effects are predicted.

Journal Article↗
PubMed2000

Olanzapine and sulpiride: a preliminary study of combination/augmentation in patients with treatment-resistant schizophrenia.

Coadministration of olanzapine, an atypical neuroleptic, with sulpiride, a selective D2 antagonist, is suggested as an efficient strategy for treating patients with resistant unremitting schizophrenia. The psychopharmacologic rationale that may account for the enhanced clinical efficacy of combining sulpiride with olanzapine and vice versa is the difference in affinity of the two drugs to brain receptors. Olanzapine affinity is related more to serotonin 5-HT2 than to dopamine-2, whereas sulpiride is considered a selective D2 blocker. The adjunction of a selective D2 antagonist to olanzapine may act as the olanzapine's augmentor by enhancing D2 blockage. This mode of treatment was introduced to six patients with chronic schizophrenia who showed noteworthy and rapid clinical improvement, supported by a decrease in their scores on the Positive and Negative Syndrome Scale and Brief Psychiatric Rating Scale. No bothersome side effects were noticed. This clinical approach is in accordance with the findings of previous reports assessing the efficacy of the combined treatment of clozapine and sulpiride. The grounds for this treatment regimen using olanzapine rather than clozapine are discussed, calling for further studies to affirm the hypothesis and clinical results.

Adult↗
PubMed2000

Jerusalem syndrome.

BACKGROUND: Jerusalem's psychiatrists expect to encounter, as the millennium approaches, an ever-increasing number of tourists who, upon arriving in Jerusalem, may suffer psychotic decompensation. AIMS: To describe the Jerusalem syndrome as a unique acute psychotic state. METHOD: This analysis is based on accumulated clinical experience and phenomenological data consisting of cultural and religious perspectives. RESULTS: Three main categories of the syndrome are identified and described, with special focus on the category pertaining to spontaneous manifestations, unconfounded by previous psychotic history or psychopathology. CONCLUSIONS: The discrete form of the Jerusalem syndrome is related to religious excitement induced by proximity to the holy places of Jerusalem, and is indicated by seven characteristic sequential stages.

Adult↗
PubMed2000

Clozapine and risperidone: combination/augmentation treatment of refractory schizophrenia: a preliminary observation.

OBJECTIVE: Clozapine and risperidone were the first two antipsychotic drugs of a new class of agents for the pharmacotherapy of schizophrenia. It has been suggested that refractory schizophrenic patients who fail to respond to neither clozapine nor risperidone may respond to a combination/augmentation strategy of both medicaments. METHOD: Three cases of individuals with unremittent schizophrenia treated via this combination are presented. Response was evaluated by clinical follow-up and PANSS rating scale. RESULTS: Good clinical results with no noticeable adverse side effects, ascertained by a reduction from baseline scores of the Positive and Negative Syndrome Scale (PANSS) were obtained in all three patients. CONCLUSION: The findings from this pilot study suggest this combination as a possible therapeutic approach for treating resistant schizophrenic patients.

Adult↗