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Biomedical subjects

M Davidson

Publications and source records attributed to M Davidson.

At least 73 records · Page 4Linked to original sources
PubMed1999

Analysis of Minnesota Multiphasic Personality Inventory-2 profiles of prospective anonymous oocyte donors in relation to the outcome of the donor selection process.

OBJECTIVE: To examine the scores of prospective anonymous oocyte donors on the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) in four outcome groups. DESIGN: Chart review. SETTING: Academic medical center. PATIENT(S): One hundred fifty prospective anonymous oocyte donors who underwent a preliminary screening and a 1-hour structured psychological interview and who completed the MMPI-2. INTERVENTION(S): Psychological evaluation prior to donation. MAIN OUTCOME MEASURE(S): Scores on the MMPI-2 and outcomes of the donor selection process. RESULT(S): Seventy (47%) women were accepted as donors and completed one donation cycle; 30 (20%) were accepted as donors but did not donate because of medical reasons or relocation; 18 (12%) were accepted as donors but were noncompliant; and 32 (21%) were rejected as donors because of psychological concerns. Statistically significant differences were found between outcome groups on scales F, K, 1, 2, 7, 8, and 0. Although these differences were statistically significant, all group subscale mean scores were in the average to low-average range and differences between group means were small. CONCLUSION(S): The MMPI-2 differentiates between prospective donor outcome groups, but psychologists need to interpret the results of the MMPI-2 carefully in the context of clinical interview information.

Female↗
PubMed1999

Behavioral analysis of PTZ-kindled rats after acute and chronic ethanol treatments.

The present study was designed to examine the response of PTZ-kindled and saline-injected animals to both acute and chronic ethanol treatment. Acute injection of ethanol (3.0 g/kg; IP) resulted in a rapid onset of loss of righting reflex (LORR) in both PTZ-kindled and saline-injected animals. However, the PTZ-kindled animals recovered from LORR significantly more quickly than control animals. Using a tilt-plane test as a measure of motor incoordination, the PTZ-kindled animals had significantly less motor incoordination compared to controls. Blood alcohol levels (BAL) were not significantly different between the groups. We also compared the degree of tolerance and dependence in chronic ethanol-treated, PTZ-kindled, and control animals. PTZ-kindled, saline-injected and naive control animals were chronically treated with ethanol vapor. The PTZ-kindled group tolerated high vapor concentrations (in terms of food consumed/rat) and, at the end of the treatment, displayed intoxication characteristics different from those of the control groups despite having similar blood alcohol levels. The PTZ-kindled group also displayed withdrawal behavior that was similar to a group of ethanol-treated animals that had experienced a prior cycle of dependency and withdrawal. These data show many intriguing similarities between animals that are PTZ-kindled and chronically treated with ethanol and suggest the use of PTZ-kindled animals as a model for alcohol withdrawal kindling.

Animals↗
PubMed1999

Long-term blood cholesterol-lowering effects of a dietary fiber supplement.

BACKGROUND: The study evaluated the blood cholesterol-lowering effects of a dietary supplement of water-soluble fibers (guar gum, pectin) and mostly non-water-soluble fibers (soy fiber, pea fiber, corn bran) in subjects with mild to moderate hypercholesterolemia (LDL cholesterol, 3.37-4.92 mmol/L). METHODS: After stabilization for 9 weeks on a National Cholesterol Education Program Step 1 Diet, subjects were randomly assigned to receive 20 g/d of the fiber supplement (n = 87) or matching placebo (n = 82) for 15 weeks and then receive the fiber supplement for 36 weeks. The efficacy analyses included the 125 subjects (58 fiber; 67 placebo) who were treatment and diet compliant. One hundred two (52 fiber; 50 placebo) completed the 15-week comparative phase. Of these subjects 85 (45 fiber; 40 placebo) elected to continue in the 36-week noncomparative extension phase. RESULTS: The mean decreases during the 15-week period for LDL cholesterol (LDL-C), total cholesterol (TC), and LDL-C/HDL-C ratio were greater (P < 0.001) in the fiber group. The mean changes from pre-treatment values in LDL-C, TC, and LDL-C/HDL-C ratio for subjects in the fiber group were -0.51 mmol/L (-12.1%), -0.53 mmol/L (-8.5%), and -0.30 (-9.4%), respectively. The corresponding changes in the placebo group were -0.05 mmol/L (-1.3%), -0.05 mmol/L (-0.8%), and 0.05 (1.5%), respectively. The fiber supplement had no significant effects (P > 0.05) on HDL cholesterol (HDL-C), triglyceride, iron, ferritin, or vitamin A or E levels. Similar effects were seen over the subsequent 36-week noncomparative part of the study. CONCLUSIONS: The fiber supplement provided significant and sustained reductions in LDL-C without reducing HDL-C or increasing triglycerides over the 51-week treatment period.

Adolescent↗
PubMed1999

Coping skills training for youths with diabetes on intensive therapy.

The purpose of this study was to determine if a behavioral intervention (coping skills training [CST]) combined with intensive diabetes management can improve the metabolic control and quality of life in adolescents who are implementing intensive therapy. A total of 77 youths (age range, 12.5-20 years) who were beginning intensive insulin therapy were randomly assigned to one of two groups: intensive management with CST or without CST. CST consists of a series of small group efforts designed to teach problem solving skills and communication. Data were collected preintervention and at 3 and 6 months post-intervention by using established clinical and psychosocial indicators. Randomization produced equivalent groups. After 6 months, subjects who received CST had better metabolic control (F = 3.89, p = .02) and better general self-efficacy (F = 4.54, p = 0.01). They reported less negative impact of diabetes on their quality of life (F = 4.55, p = .01) and had fewer worries about diabetes (F = 3.82, p = .02). Thus, nurses may find CST useful in assisting youths with diabetes to achieve metabolic and quality of life goals.

Adaptation, Psychological↗
PubMed1999

A naturalistic study comparing the efficacy of a memory enhancement course to a general academic course.

OBJECTIVE: The goal of this study was to compare the effectiveness of a memory improvement course to a course in general psychology. METHODS: Thirty-four healthy elderly persons enrolled in a college memory improvement course for senior citizens, and 33 who enrolled in a parallel course, Introduction to Psychology, were tested on verbal and visual memory prior to and after completing the course. Before they took the course, they were also assessed on subjective memory (self-assessment scale of memory efficacy) and psychological distress (General Health Questionnaire). Changes within and between groups were examined using multivariate analysis of covariance to control for baseline scores. RESULTS: Both groups had similar improvements on all cognitive measures. The memory improvement course group showed very significant correlations between objective and subjective memory. CONCLUSIONS: It appears that participation in academic courses is associated with improvement in certain aspects of cognitive functioning. Awareness of objective memory functioning may be a natural selection factor or a significant motivating factor for healthy elderly to enroll in memory enhancement courses.

Aged↗
PubMed1999

Four new DP alleles identified in a study of 500 unrelated bone marrow donor-recipient pairs.

HLA-DP genotyping of 500 donor recipient pairs in a retrospective analysis sponsored by the National Marrow Donor Program (NMDP) identified four new DP alleles, two DPB1 and two DPA1. DNA sequencing confirmed that DPB1*8001 and *8101, each found in a single individual, are novel combinations of previously described sequence motifs in the six variable regions of DPB1. DPA1*02014, found in two individuals, is identical to DPA1*02011 except for a novel silent substitution, a G to A transition at the third position of codon 14. DPA1*01032, found in one individual, is identical to DPB1*01031 except for a silent G to A transition at the third position of codon 20. The identification of these novel alleles brings the total number of reported DPB1 alleles to 85 and DPA1 alleles to 15.

Alleles↗
PubMed1999

A calcium signaling defect in the pathogenesis of a mitochondrial DNA inherited oxidative phosphorylation deficiency.

In recent years, genetic defects of the mitochondrial genome (mtDNA) were shown to be associated with a heterogeneous group of disorders, known as mitochondrial diseases, but the cellular events deriving from the molecular lesions and the mechanistic basis of the specificity of the syndromes are still incompletely understood. Mitochondrial calcium (Ca2+) homeostasis depends on close contacts with the endoplasmic reticulum and is essential in modulating organelle function. Given the strong dependence of mitochondrial Ca2+ uptake on the membrane potential and the intracellular distribution of the organelle, both of which may be altered in mitochondrial diseases, we investigated the occurrence of defects in mitochondrial Ca2+ handling in living cells with either the tRNALys mutation of MERRF (myoclonic epilepsy with ragged-red fibers) or the ATPase mutation of NARP (neurogenic muscle weakness, ataxia and retinitis pigmentosa). There was a derangement of mitochondrial Ca2+ homeostasis in MERRF, but not in NARP cells, whereas cytosolic Ca2+ responses were normal in both cell types. Treatment of MERRF cells with drugs affecting organellar Ca2+ transport mostly restored both the agonist-dependent mitochondrial Ca2+ uptake and the ensuing stimulation of ATP production. These results emphasize the differences in the cellular pathogenesis of the various mtDNA defects and indicate specific pharmacological approaches to the treatment of some mitochondrial diseases.

Adenosine Triphosphatases↗
PubMed1999

Intensification of the stem cell transplant induction regimen results in increased treatment-related mortality without improved outcome in multiple myeloma.

Randomized trials conducted by the Intergroupe Française du Myelome (IFM) demonstrate that the use of high-dose chemotherapy (HDCT) and stem cell transplantation (SCT) improves event-free (EFS) and overall survival (OS) in younger patients with multiple myeloma (MM). Nevertheless, current HDCT regimens remain inadequate as all patients ultimately relapse following SCT. In an attempt to improve the OS of MM patients post-SCT we used an escalated HDCT regimen incorporating both intensified melphalan (160 mg/m2) and fractionated total body irradiation (12 Gy) to maximize the dose response of myeloma cells to these agents and included infusional etoposide 60 mg/kg in an attempt to eradicate clonal B cells potentially contributing to the myeloma clone. One hundred patients with MM received this intensified SCT regimen. The 100-day treatment-related mortality was 12% predominantly reflecting the development of interstitial pneumonitis (IP) in 28% of patients of whom 7/28 (25%) died. The predicted 5-year OS and EFS following the diagnosis of MM were 60% and 35%, respectively. The median OS from the time of transplant is 41 months and the median EFS is 28 months. More than two prior chemotherapy regimens, previous radiation therapy (RT) and the presence of an abnormal karyotype involving chromosomes 11 or 13 were significantly predictive of poor outcome. Interferon maintenance was not associated with improved outcome. Intensification of the HDCT regimen utilizing etoposide together with escalated melphalan and TBI increases morbidity and mortality without increasing OS beyond that reported with less toxic regimens.

Adult↗
PubMed1999

Thrombosis, markers of thrombotic risk, indwelling central venous catheters and antithrombotic prophylaxis using low-dose warfarin in subjects with malignant disease.

Markers of thrombotic risk--fibrinogen, factor VIII and immunoglobulin G (IgG) anticardiolipin titres--were measured, and the presence of lupus anticoagulant and factor V Leiden were assessed in 84 patients with a solid or haematological malignancy. These patients were monitored, following the insertion of an indwelling venous catheter, for thrombosis. Fifty-five were given prophylactic low-dose warfarin. Over a mean of 15 weeks there were 10 (12%) thrombotic events in 10 patients. Seven were on warfarin. Haemorrhagic problems occurred in three (5%), all on warfarin. Of the 84 patients, 86% had raised fibrinogen levels, 37% elevated factor VIII and 44% raised anticardiolipin levels. Lupus anticoagulant was present in five and three were heterozygous for factor V Leiden. A high prevalence of a range of prothrombotic changes was confirmed and the frequent presence of low-titre anticardiolipin antibody in subjects with malignancy demonstrated. However, none of these parameters predicted the development of thrombosis (P > 0.05).

Anticoagulants↗
PubMed1999

Behavioral and intellectual markers for schizophrenia in apparently healthy male adolescents.

OBJECTIVE: Subtle behavioral and intellectual abnormalities are often present in apparently healthy adolescents who later develop schizophrenia. The authors investigated whether these abnormalities can predict vulnerability for schizophrenia before the first psychotic manifestation. METHOD: The study consisted of linking the Israeli Draft Board Registry with the National Psychiatric Hospitalization Case Registry. The draft board tests measure intelligence, social functioning, organizational ability, interest in physical activity, and individual autonomy. Patients (N = 509) were compared to nonpatients, i.e., adolescents not appearing in the National Psychiatric Registry (N = 9,215), matched to patients by age, gender, and school attended at time of testing. RESULTS: Healthy male adolescents who were later hospitalized for schizophrenia had significantly lower test scores on all measures than adolescents not reported to the National Psychiatric Registry. The strongest predictors for schizophrenia were deficits in social functioning, organizational ability, and intellectual functioning. When patients were compared to matched nonpatients, the prediction model had a 75% sensitivity, a 100% specificity, a positive predictive value of 72%, and an overall rate of correct classification of 87.5%. Applied to the Israeli Draft Board Registry, the model yielded a sensitivity of 74.7%, a validated specificity of 99.7%, and a positive predictive value of 42.7%. CONCLUSIONS: This study demonstrated that simple assessment tools can predict predisposition to schizophrenia in healthy male adolescents. The model's predictive ability does not change as a function of the time elapsed between testing and first hospitalization. This suggests that the model identifies apparently healthy individuals who will manifest the disease later who are not prodromal to psychosis. Easily applied tools allowing early identification of schizophrenia or vulnerability to it may enable early intervention.

Adolescent↗
PubMed1999

Over-the-counter nicotine patch therapy for smoking cessation: results from randomized, double-blind, placebo-controlled, and open label trials.

OBJECTIVES: The purpose of this study was to determine the efficacy and safety of the nicotine patch for smoking cessation in an over-the-counter environment. The years of study were 1994 to 1995. METHODS: Parallel 6-week trials were conducted: a placebo-controlled trial of no-cost 22-mg, 24-hour nicotine patch therapy and an open label trial of the same therapy with patches purchased by subjects. Participants (n = 958) were 18 years or older, had smoked at least 15 cigarettes daily for at least 6 months, and were enrolled at 3 study sites. The main outcome measure was self-reported smoking abstinence confirmed by expired carbon monoxide measurements. RESULTS: Smoking cessation rates in the placebo-controlled trial were 16.8% and 9.6% at week 6 and 8.7% and 4.3% at week 24 for the active patch and placebo groups, respectively. Smoking cessation rates in the open label-pay trial were 19.0% and 10.8% at weeks 6 and 24, respectively. A slight increase in adverse cardiovascular events was noted only in the open label-pay group in comparison with the placebo group. CONCLUSIONS: In an over-the-counter environment, the 22-mg, 24-hour nicotine patch is effective and safe for smoking cessation treatment.

Administration, Cutaneous↗
PubMed1999

Validation of a Hebrew selective reminding test.

We developed a Hebrew version for the Buschke Selective Reminding Memory Test, with three parallel forms. This Hebrew version was administered in counterbalanced order to 24 normal subjects aged 14-77 years. We studied the reliability between parallel forms, and the validity and sensitivity memory reduction in normal aging. Data were compared to American norms. The three Hebrew forms were found to be of equal difficulty, with correlation coefficients of .6 to .7 (p's < .01). Age affected the great majority of memory performances, i.e., lower performance with increasing age. Test performance was equivalent to American norms within 6%. We conclude that this Hebrew version is reliable and valid, and can be used on Hebrew-speaking populations to assess memory functions.

Adolescent↗
PubMed1999

Effect of respiratory tract disease on pharmacokinetics of tilmicosin in rats.

BACKGROUND AND PURPOSE: In rats, murine respiratory mycoplasmosis is caused by Mycoplasma pulmonis. Tilmicosin, a macrolide antibiotic, has good tissue penetration and reaches high concentration in the lungs. Therefore, a model for studying the effects of disease on pharmacokinetics of tilmicosin was developed, using LEW rats. METHODS: Seventy-two LEW rats were assigned at random to two groups: one group was inoculated with M. pulmonis, and the other served as an uninoculated control group. On postinoculation day 31, all rats received a single dose of tilmicosin (20 mg/kg of body weight, subcutaneously). RESULTS: Concentration of tilmicosin in the lungs of both groups of rats was significantly higher than serum tilmicosin concentration at all times. Infected rats had significantly higher lung tilmicosin concentration than did noninfected rats. No correlation was found between pH of the lungs and tilmicosin concentration in the lungs in either treatment group, nor did treatment have any effect on pH of the muscle. CONCLUSION: Tilmicosin accumulates in the lungs, and infection/inflammation further improves its tissue penetration.

Animals↗
PubMed1998

Inositol levels are decreased in postmortem brain of schizophrenic patients.

BACKGROUND: A previous study reported decreased levels of inositol in frontal cortex of postmortem brain from bipolar patients and suicide victims. The aim of the present study was to test the specificity of this finding. METHODS: Inositol and the enzyme that synthesizes it, inositol monophosphatase, were measured in postmortem brain tissue from frontal and occipital cortex and cerebellum from 10 schizophrenic patients and the previously reported controls. Inositol levels were assayed gas-chromatographically as trimethylsilyl derivatives with mannitol as an internal standard. Inositol monophosphatase activity in brain homogenates was measured as the difference between phosphate release from inositol-l-phosphate in the absence and in the presence of Li+. RESULTS: Inositol was significantly reduced in all three areas in the schizophrenic patient' brains: inositol monophosphatase was unchanged. Postmortem interval did not correlate with inositol levels and did not differ between control group and schizophrenic patients. CONCLUSIONS: These results suggest an abnormality of second messenger precursor availability in common with schizophrenia and affective psychopathology.

Aged↗
PubMed1998

Confirmed previous infection with Chlamydia pneumoniae (TWAR) and its presence in early coronary atherosclerosis.

BACKGROUND: Chlamydia pneumoniae has been identified in coronary atheroma, but concomitant serum antibody titers have been inconsistently positive and unavailable before the detection of early or advanced atherosclerotic lesions. METHODS AND RESULTS: This retrospective investigation was performed on premortem serum specimens and autopsy tissue from 60 indigenous Alaska Natives at low risk for coronary heart disease, selected by the potential availability of their stored specimens. Serum specimens were drawn a mean of 8.8 years (range, 0.7 to 26.2 years) before death, which occurred at a mean age of 34.1 years (range, 15 to 57 years), primarily from noncardiovascular causes (97%). Coronary artery tissues were independently examined histologically and, for C pneumoniae organism and DNA, by immunocytochemistry (ICC) and polymerase chain reaction (PCR) with species-specific monoclonal antibody and primers. Microimmunofluorescence detected species-specific IgG, IgA, and IgM antibody in stored serum. C pneumoniae, frequently within macrophage foam cells, was identified in coronary fibrolipid atheroma (raised lesions, Stary types II through V) in 15 subjects (25%) and early flat lesions in 7 (11%) either by PCR (14, 23%) or ICC (20, 33%). The OR for C pneumoniae in raised atheroma after a level of IgG antibody > or =1:256 >8 years earlier was 6.1 (95% CI, 1.1 to 36.6) and for all coronary tissues after adjustment for multiple potential confounding variables, including tobacco exposure, was 9.4 (95% CI, 2.6 to 33.8). CONCLUSIONS: Serological evidence for C pneumoniae infection frequently precedes both the earliest and more advanced lesions of coronary atherosclerosis that harbor this intracellular pathogen, suggesting a chronic infection and developmental role in coronary heart disease.

Adolescent↗