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Biomedical subjects

J Haber

Publications and source records attributed to J Haber.

At least 19 recordsLinked to original sources
PubMed1996

The effect of linoleic acid on pH inside sodium bis(2-ethylhexyl)sulfosuccinate reverse micelles in isooctane and on the enzymic activity of soybean lipoxygenase.

The effective pH of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles (pHrm), containing buffers of different pH (pHst) and various amounts of linoleic acid, was studied within the range of compositions used to study the activity of soybean lipoxygenase in reverse micelles. Significant shifts of pHrm versus pHst were observed for the solutions of relatively higher pHst, dependent on linoleic acid and buffer concentrations. The effect diminished as pHst became closer to 7. When low-ionic-strength buffers were added to AOT solutions in isooctane, a significant buffering effect of linoleic acid in reverse micelles was observed. Solubilization of > 3 mM linoleic acid in micellar solutions containing 25 mM buffers gave the observed pHrm values almost independent of pHst. This effect diminished with the ionic strength of the buffering solution, but did not vanish even at 200 mM buffer. The observed effects result from the balance between ionization of linoleic acid and its partition between the water pool and the micellar interface. The enzymic activity of soybean lipoxygenase in the AOT reverse micellar solutions of the determined pHrm values was also studied. A significant reduction of the kinetics of the enzymic activity was observed, for all studied reverse micellar solutions. Changes of pHrm, caused by the presence of acidic substrate (linoleic acid) do not explain the observed reduction of activity directly through the effect on the enzyme. Due to unfavourable partition of the substrate between the microphases present in the systems, enhanced by reduction of pH at higher total concentrations of linoleic acid, the saturation of the enzyme with the substrate was not observed in the system and is difficult to attain experimentally in reverse micelles. A shift of the lipoxygenase activity/pHrm profile but negligible shift of the activity/pHst profile, with respect to aqueous buffer solutions, were observed. This indicates that either the information given by pH indicators used does not reveal the true pH of the enzyme in these reverse micelles, or that the sample of the enzyme is pH-insensitive over a broader pH range than results from the relationship observed for linoleic acid in aqueous solutions. The latter conclusion is consistent with the data on lipoxygenase activity towards linoleyl sulfate in aqueous solutions [Bild, G. S., Ramadoss, C. S. & Axelrod, B. (1977) Lipids 12, 732-735]. Conditions for measuring pH-independent lipoxygenase activity in reverse micelles are discussed.

Dioctyl Sulfosuccinic Acid↗
PubMed1996

[Recombinant human erythropoietin in the treatment of anemia associated with lymphoproliferative diseases--chronic lymphadenosis and multiple myeloma].

UNLABELLED: The etiology of anaemia associated with tumours is multifactorial. One of the mechanisms of development of anaemia in tumours are so-called chronic diseases anaemias, the main feature of which is inadequate production of endogenous erythropoietin (EPO). The objective of the investigation was to test the effect of recombinant human erythropoietin (rHuEPO) in the treatment of anaemia (rise of haematocrit, Hb) in patients with chronic lymphatic leukaemia (CLL) and multiple myeloma (MM) and the effect of this treatment on the quality of life. The authors evaluated at the same time the impact of the endogenous EPO level before treatment and its predictive value as regards the therapeutic response. PATIENTS: The investigation comprised a total of 14 patients (6 CLL, 8 MM). The basic criterion for inclusion in the group was a Ht value lower than 0.32 and Hb less than 105 g/l. The examination protocol was focused on elimination of other causes of anaemia. During the 12-week investigation the patients completed a questionnaire "Quality of life" which reflected their subjective evaluation of the effect of treatment. The patients themselves administered r-HuEPO three times a week by the s.c. route--an initial dose of 150 U/kg with the possibility to increase the dose to 300 U/kg. RESULTS: A therapeutic response was obtained in four patients with CLL and eight patients with MM. Respondents with CLL had endogenous EPO values lower than 300 U/l, seven MM respondents lower than 200 U/l, one 400 U/l. The Hb level of the patients rose and the quality of life improved. All patients tolerated treatment very well and the authors did not observe any serious undesirable effects. CONCLUSION: The investigation confirmed the therapeutic effect of r-HuEPO in patients with a lower baseline value of EPO. Subjective evaluation (questionnaire) correlated with objective evaluation (Ht, Hb). Assessment of the endogenous EPO level before treatment is according to the authors one of the important primary predictive parameters and EPO values between 200 and 300 U/l are the upper range where a therapeutic effect can be expected with the highest probability. The authors conclude also that a secondary predictive criterion of the response is evaluation of the therapeutic effect after 4-5 weeks treatment when a rise of Hb by at least 20 g/l is an argument for further treatment.

Aged↗
PubMed1994

Wound botulism.

Wound botulism is a rare infectious and toxicologic complication of trauma and i.v. drug abuse. Only 39 cases have been reported in detail in the English literature. This case report describes a patient with wound botulism who presented to four medical facilities before receiving definitive diagnosis and treatment. Although his history and physical examination were consistent with wound botulism, diagnosis and therapy were delayed because this rare disease was not considered initially in the differential diagnosis. Wound botulism should be considered in trauma patients and i.v. drug abusers who present with cranial nerve palsies and descending paresis.

Abscess↗
PubMed1994

Cigarette smoking: a major risk factor for periodontitis.

Cigarette smoking is a risk factor for many diseases, and recent evidence indicates that it adversely affects periodontal health. A number of epidemiologic studies have shown strong associations between smoking and the prevalence and severity of periodontitis, as well as interproximal bone loss. Although the pathogenesis of periodontitis in smokers is poorly understood, there are data suggesting that smoking causes defects in neutrophil function, impaired serum antibody responses to periodontal pathogens, and potentially diminished gingival fibroblast function. The prevalence and severity of periodontitis in former smokers is decreased compared to current smokers, providing evidence that smoking cessation is beneficial. Smoking markedly influences response to treatment, and a subset of smokers predominates among refractory periodontitis patients who are resistant to conventional treatment. A patient's smoking history is a useful clinical predictor of future disease activity. Current estimates suggest that smoking is associated with a large proportion of periodontitis cases and constitutes a major public dental health problem.

Humans↗
PubMed1994

Smoking is a major risk factor for periodontitis.

Cigarette smoking is a risk factor for many diseases, and recent evidence indicates that smoking adversely influences periodontal health. A number of epidemiologic studies have shown strong associations between smoking and the prevalence and severity of periodontitis, as well as interproximal bone loss. Whereas the pathogenesis of periodontitis in smokers is poorly understood, there are data suggesting defects in neutrophil function, impaired serum antibody responses to periodontal pathogens, and potentially diminished gingival fibroblast function. The prevalence and severity of periodontitis in former smokers is decreased compared with current smokers, providing evidence that smoking cessation is beneficial. Smoking markedly influences response to treatment, and a subset of smokers predominates among patients with refractory periodontitis whose disease is resistant to conventional treatment. Smokers are a high-risk group for periodontitis, and smoking history is a useful clinical predictor of future disease activity. Current estimates suggest that smoking is associated with a large proportion of periodontitis cases and constitutes a major dental public health problem. A new disease category, smoking-associated periodontitis, is proposed, given the unique characteristics of smokers with periodontitis.

Humans↗
PubMed1993

Activity and spectroscopic properties of bovine liver catalase in sodium bis(2-ethylhexyl)sulfosuccinate/isooctane reverse micelles.

Spectroscopic properties such as ultraviolet-visible spectroscopy, circular dichroism, steady-state fluorescence and the catalytic activity of bovine liver catalase (BLC) have been studied in reverse-micelles microemulsions formed by sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in isooctane. Activity measurements were carried out with the highly water soluble hydrogen peroxide as substrate as a function of temperature and pH, at various concentrations of substrate, enzyme, AOT and at different w0 values (w0 = [H2O]/[AOT]). The folding of catalase in reverse micelles is not drastically altered, although there are changes in the local surrounding of the prosthetic group. Kinetic measurements have been carried out under first-order conditions at low substrate concentration. They indicate that the measured substrate decomposition rate is limited by the exchange of substrate molecules between the substrate-filled and the enzyme-containing micelles. The specificity constant, ks = kcat/KM, as related to water pool concentrations, k(s,wp)rm, was, at all w0 values, considerably lower than ks measured in buffer (ksb). In contrast, overall values of ks in reverse micelles, k(s,ov)rm, were always 2-4-times higher than ksb. This apparent superactivity can, however, be ascribed to concentration effects. No 'bell-curve' to describe the w0 dependence of catalase activity in reverse micelles was found, k or ks increasing monotonously up to w0 = 50.

Animals↗
PubMed1993

Evidence for cigarette smoking as a major risk factor for periodontitis.

The role of smoking as a risk factor for periodontitis was assessed separately in diabetic and nondiabetic study groups. Subject listings stratified for age (19 to 40 years) and sex were obtained for subjects with insulin-dependent diabetes mellitus (IDDM) and nondiabetic subjects. For both the IDDM group (n = 132) and the nondiabetic group (n = 95), age and sex stratified samples were constructed by random selection of subjects from each subject listing. Patients were recruited by phone, examined, and their medical and dental histories obtained. Among nondiabetic subjects, the prevalence of periodontitis was markedly higher among current smokers compared with never smokers (P < or = 0.005) in both the 19 to 30 year-old (46% vs. 12%) and 31 to 40 year-old groups (88% vs. 33%). The subject mean percent of sites with gingival pocket depth > or = 4 mm was higher among current smokers than never smokers (P = 0.001) in the 19 to 30 (8.2% vs. 3.4%) and 31 to 40 (14.3% vs. 4.3%) age groups. The effects of smoking among IDDM subjects were similar to that observed in the nondiabetic population. There were no differences between current and never smokers in the proportion of sites positive for plaque. Attributable risk percents from prevalence data suggest that among nondiabetic subjects, a large proportion, perhaps as much as 51% of the periodontitis in the 19 to 30 year old group and 32% of the periodontitis in the 31 to 40 year old group, is associated with smoking.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Bridging the nursing research-practice gap through research utilization.

This article explores the gap that currently exists between nursing research and nursing practice. The aim is to promote the conversion of new knowledge into practical innovations. Barriers to research utilization in practice settings come from both the academic and clinical arenas. Innovative models and strategies are needed to overcome these barriers. The purposes and value of research utilization and the clinical and academic strategies that facilitate research are discussed. Supporting clinical studies are provided as exemplars.

Clinical Nursing Research↗
PubMed1993

A construct validity study of a Differentiation of Self Scale.

The purpose of this study was to establish construct validity of the Haber Level of Differentiation of Self Scale (LDSS) that measures selected aspects of the construct, differentiation of self, the key concept of the Bowen Theory. During stage one of this study, a 32-item Likert-type LDSS, which contained two subscales, Emotional Maturity, (EM), and Emotional Dependency (ED), was administered to 372 volunteer subjects. Factor analytic and correlational findings indicated support for a 24-item unidimensional rather than a 32-item two subscale instrument. Recalculation of coefficient alpha (.90) also supported the unidimensional structure of the LDSS. During stage two of this study, the revised 24-item LDSS was administered to 372 volunteer subjects, who also completed the State-Trait Anxiety Inventory, the Life Experience Survey, and the Behavior Checklist. Hypotheses predicted that there would be negative relationships between differentiation of self and trait anxiety, state anxiety, adult psychological dysfunction, and negative impact stress. Findings indicate support for all hypotheses at the p < .01 level of significance or greater. Data from this study suggest that the 24-item LDSS is a valid and reliable unidimensional family assessment tool that accurately measures specific aspects of the construct, differentiation of self. The LDSS can be used by nurses and other professionals to assess individual and family functioning in a variety of health care settings.

Adaptation, Psychological↗
PubMed1992

Cigarette smoking in a periodontal practice.

This case-control study compares the prevalence of cigarette smoking among patients in a periodontal practice (cases) with that of patients in referring general dental practices (controls). Smoking histories of patients (age greater than or equal to 25 years) in a periodontal practice and five general dental practices were obtained by questionnaire. From the general practices, only patients reporting negative histories for periodontitis were studied. Periodontal status of the periodontal practice patients was based on bone loss from full mouth radiographic surveys and gingival pocket depths. Patients were stratified by age (25 to 40, 41 to 55, and greater than 55 years) and sex. The combined frequency of current or former cigarette smoking reported by 196 periodontal practice patients with moderate or advanced periodontitis (M-A perio group) was higher than that reported by 209 general dental practice patients (gen prac group) in all age and sex categories. The age and sex adjusted summary odds ratio for a positive smoking history among M-A perio subjects relative to gen prac subjects was 2.6 (P less than 0.001). Separate corresponding odds ratios (age and sex adjusted) for current smoking versus never smoking in the two groups were 3.3 (P less than 0.001) and for former smoking versus never smoking 2.1 (P less than 0.004). Among current smokers, patients in the M-A perio group reported heavy smoking (greater than 10 cigarettes/day) relatively more often than control subjects (adjusted R.O. = 5.7; P less than 0.001). In the M-A perio group the frequency of current smoking increased with disease severity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Microbiology of healthy and diseased periodontal sites in poorly controlled insulin dependent diabetics.

A group of poorly-controlled insulin dependent diabetes mellitus (IDDM) patients were examined in a cross-sectional design for total microbial levels, microbial incidence, and the percent levels of selected periodontal microorganisms. These organisms were selected on the basis of prior reports that associated them with either periodontal disease or health. One periodontally-healthy and one periodontally-diseased site were examined in each IDDM patient. Increased levels of the periodontal pathogens Prevotella intermedia, P. melaninogenica spp., Bacteroides gracilis, Eikenella corrodens, Fusobacterium nucleatum and Campylobacter rectus (formerly Wolinella recta) were found at the periodontal diseased sites. Increased prevalence of the organisms P. intermedia, P. melaninogenica spp., and C. rectus were found at the diseased sites. A significantly higher percentage of P. intermedia was found at the sites exhibiting deep pockets and attachment loss.

Adult↗
PubMed1991

Dominant low responsiveness in the IgG response of mice to the complex protein antigen type 1 fimbriae from Actinomyces viscosus T14V.

Type 1 fimbriae from Actinomyces viscosus T14V, composed of a complex protein of Mr 65,000, mediate the adherence of A. viscosus T14V to the host, whereas type 1 fimbriae-specific antibodies inhibit adherence. Genetic control of the serum IgG response to type 1 fimbriae was evaluated in a series of inbred, hybrid, recombinant inbred, and back-cross mice. Mice were given i.p. injections of 10(8) A. viscosus T14V cells in saline on days 0 and 14, and IgG anti-type 1 fimbriae in sera obtained on day 26 were measured by ELISA. Segregation analysis of the responses of (BALB/cJ x A/J)F1 x A/J backcross mice suggested polygenic control. Linkage analysis in (BALB/cJ x A/J)F1 x A/J backcross and SWXL recombinant inbred mice suggested control by genes linked with H-2 and with Ly-17 and Akp-1. In several F1 hybrid strains derived from H-2-disparate high and low responder parental strains, low responsiveness was dominant. The F1 derived from the H-2-identical high and low responder strains CBA/J and C3H/HeJ was a low responder, suggesting that dominant low responsiveness was mediated by non-H-2-linked genes. A three-gene model is proposed for regulation of the type 1 fimbriae response, including an MHC-linked gene, a gene linked with Ly-17 and Akp-1 on the telomeric portion of chromosome 1, and a background gene whose linkage is unknown.

Actinomyces↗
PubMed1991

A pilot matching program for applicants to five California medical schools.

This report summarizes the results of the 1989 California Medical School Matching Program Pilot Study. The study demonstrated that the technical aspects of a matching program for medical school applicants can be successfully operated. The applicant participation was 48.7%, with 76.1% of the ranked students responding. The schools ranked 1,122 students, with approximately 38% being ranked by more than one school. Of the 905 students who were matched to a school, 88% were matched to one of their top three choices. Of the students who had actually accepted a position at a school under the normal admission procedure, 60% had been matched to the same school by the matching program. The conclusions are that the program operates properly, that it fulfills the wishes of the students as well as could be expected, and that it parallels the current admission process to a reasonable degree.

California↗