PubMed Health⌕ Search

Biomedical subjects

F Levy

Publications and source records attributed to F Levy.

At least 19 recordsLinked to original sources
PubMed1992

Relationships between exposure to spores from Rhizopus microsporus and Paecilomyces variotii and serum IgG antibodies in wood trimmers.

A longitudinal study of wood trimmers exposed to mould spores was carried out from 1985 to 1988. Exposure to airborne spores from Rhizopus microsporus ssp. rhizopodiformis and Paecilomyces variotii was measured by scanning electron microscopy of filter samples. Specific IgG antibodies to these moulds were measured by ELISA in serum samples collected at half-year intervals. Antibody levels to R. microsporus and P. variotii were higher in wood trimmers than in other sawmill workers whose jobs had an assumed lower exposure to mould spores. Antibody levels were significantly elevated after periods with high exposure compared to antibody levels in the same wood trimmers after periods with low exposure. Antibodies were also found in newly employed wood trimmers. These wood trimmers were exposed to 1,300 x 10(3) R. microsporus spores/m3 and 130 x 10(3) P. variotii spores/m3 (arithmetic mean exposure). Antibody levels in the newly employed wood trimmers were similar to antibody levels in wood trimmers who had already worked in the trimming department before the start of the study. Antibody levels to R. microsporus and P. variotii in wood trimmers can be regarded as indicators of fairly recent exposure. There were, however, large differences between the individual antibody levels of similarly exposed wood trimmers.

Adult↗
PubMed1992

Induction of DNA-repair synthesis (UDS) in rat pleural mesothelial cells by urine of subjects exposed to genotoxic agents.

Unscheduled DNA synthesis was determined in confluent rat pleural mesothelial cells arrested in G0/G1 with hydroxyurea by the measurement of [3H]thymidine incorporation into DNA. Cells were treated with concentrated urine or serum from subjects exposed to certain genotoxic agents, i.e. eight cancer patients treated with radiotherapy and/or chemotherapy (r/c cancer patients) and six chromium workers. Two additional groups consisted of six nonoccupationally exposed healthy smokers and five control volunteers who were nonsmokers and nonexposed. [3H]thymidine incorporated into DNA of all samples was measured by liquid scintillation counting and of urine samples from r/c cancer patients by autoradiography. Compared to the level observed in untreated cells, a statistically significant increased [3H]thymidine incorporation was found in cells treated with urine from 7 of 8 r/c cancer patients and from 5 of 6 chromium workers. In contrast, urine from control volunteers had no effect on the unscheduled DNA synthesis response and urine from only one smoker significantly enhanced [3H]thymidine incorporation into DNA. No clear-cut difference between groups was obtained with serum. These results suggest that urine could be useful to monitor subjects exposed to genotoxic agents.

Adult↗
PubMed1992

Congenital absence of the internal carotid artery.

A case of a 27 year old male who was found to have the unusual congenital absence of one internal carotid artery is presented. A second case with similar but slightly different X-ray findings due to occlusion of the internal carotid is presented for comparison. Only forty cases of agenesis of the internal carotid artery have been found by us in the literature and this appears to be the first from Africa.

Adult↗
PubMed1991

Metastatic potential and substrate dependence of cell motility and attachment in the Dunning R-3327 rat prostatic adenocarcinoma model.

Cancer cell motility has been associated with metastatic potential of sublines of the Dunning R-3227 rat prostatic adenocarcinoma model. However, three sublines of high motility lacked the capacity for metastasis. In all previous works, motility has been studied upon plastic and only upon attached cells at least 18 h after gravity plating. We studied two highly motile sublines; MAT-LyLu metastasizes to lungs and lymph nodes whereas PIF-1 metastasizes rarely. We compared the motility and attachment capability of cells from the Dunning model in serum-free media upon plastic, glass, laminin, type IV collagen, fibronectin, and elastin to determine whether study upon more physiological surfaces could better explain the discrepancy in metastatic capability observed in vivo. In the high-motility low-metastatic PIF-1 and high-motility high-metastatic MAT-Lylu sublines, membrane ruffling, pseudopodal extension, and cellular translation upon plastic in serum-free media were reduced (P less than 0.0001) by 33 and 31, 70 and 60, and 77 and 65%, respectively. When returned to serum-containing media, biological characteristics (histology, chromosomal number, growth rate, host survival, and metastatic potential) were unchanged. Motility was affected by substrate (analysis of variance, P less than 0.05); however, no consistent pattern of enhancement or detriment occurred in any substrate across both sublines. When motility was compared between sublines, membrane ruffling and cellular translation were relatively unaffected by substrate, whereas pseudopodal extension was altered significantly by different substrates. However, upon individual substrates, no significant differences in motility existed between the two sublines to resolve the inconsistency of high-motility but low-metastatic potential in the PIF-1 subline. Therefore, we examined cell attachment, since in order for a metastatic cell to be motile upon substrate, it must first attach to it. Percentage of 10(5) cells attached was determined in serum-free media with the use of a cell counter after 1, 2, 4, 8, and 16 h on plastic and plastic coated with laminin, fibronectin, elastin, or type IV collagen. Cell attachment increased with time (P less than 0.05) on all substrates for MAT-LyLu (r = 0.95) and PIF-1 (r = 0.98). Attachment of MAT-LyLu cells was impaired by fibronectin and enhanced by elastin, laminin, and type IV collagen compared to plastic at all time points.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗
PubMed1991

Hyperactivity and the fragile X syndrome.

Workers who have claimed an association between Fragile X [fra(x)] Syndrome and Hyperactivity and aggressive behavior have done so despite the lack of controlled studies using standard diagnostic criteria. Accordingly, we provided a controlled test of the hypothesis that individuals with the fra(x) Syndrome are more hyperactive and have more symptoms of aggression than other mentally retarded individuals. The test formed part of a study to assess autistic behavior in fra(x) individuals. A sample of fra(x) individuals was obtained from the register of a clinical genetics unit and individually matched for age, sex, and IQ with mentally retarded individuals selected from assessment centres. Forty-five pairs of fra(x) cases and control individuals were compared on criteria which reflected DSM-III concepts of hyperactivity and on criteria reflecting aggressive behavior. The comparison failed to find a higher prevalence of these symptoms in the fra(x) group. An analysis of the study's statistical power suggested that it is unlikely that the investigation failed to detect a large to medium difference between fra(x) individuals and control individuals in the symptoms investigated.

Adolescent↗
PubMed1991

Preoperative prediction of pathological tumor volume and stage in clinically localized prostate cancer: comparison of digital rectal examination, transrectal ultrasonography and magnetic resonance imaging.

Accurate preoperative staging is important for proper selection of patients for radical retropubic prostatectomy. Preoperative staging by digital rectal examination, transrectal ultrasound, magnetic resonance imaging (MRI), Gleason grade and prostate specific antigen was compared to pathological stage for 25 patients who underwent radical retropubic prostatectomy. The predictive value for tumor confinement was 36% by rectal examination, 37% by ultrasound and 30% by MRI. The predictive value for extracapsular disease was 100% by rectal examination, 83% by ultrasound and 66% by MRI. Preoperative determinations of tumor volume by any modality did not correlate with pathological tumor volume. Digital rectal examination, ultrasound and MRI clinically understage the disease in most patients but they may be reliable to predict extracapsular disease.

Aged↗
PubMed1991

A genetic analysis of reproductive barriers in Phacelia dubia.

Investigations into the genetic basis of reproductive barriers among recognized and putative varieties in Phacelia dubia have provided evidence that even among closely related taxa, multiple pathways can lead to reproductive isolation. A nuclear-based reproductive barrier, expressed as partial hybrid sterility of both pollen and ovules, isolated each pair of recognized varieties. There was no evidence of pre- or post-fertilization barriers; all reproductive barriers were manifested as hybrid gametic sterility. Reproductive relationships of two putative varieties were studied to examine the early stages of reproductive isolation in this group. Both putative varieties exhibited partial reproductive isolation from the recognized varieties in spite of their lack of morphological differentiation from recognized varieties. The barrier isolating one putative variety was similar to the barrier among recognized varieties. The second putative variety and a recognized variety were partially isolated by a unidirectional, nuclear-cytoplasmic barrier that reduced only pollen fertility. The nuclear-cytoplasmic barrier suggested a new application of Haldane's rule.

Alleles↗
PubMed1991

Female effect in sheep. II. Role of volatile substances from the sexually receptive female; implication of the sense of smell.

The importance of olfactory cues in inducing luteinizing hormone and testosterone secretion as a response to stimulation by sexually receptive ewes has been tested. In sexually experienced rams, olfactory stimulation with urine, wool and vaginal secretions from sexually receptive females placed in a mask did not induce an endocrine response. The female-induced secretion of LH and testosterone was similar in anosmic, sham-operated and in control rams. These results show that olfactory cues are not necessary in the mediation of interindividual stimulation of endocrine response in the sexually experienced ram.

Animals↗
PubMed1991

The dopamine theory of attention deficit hyperactivity disorder (ADHD).

Clinical, animal and neuroanatomical studies of differential isomer and dosage effects of CNS stimulant medications on behaviour are reviewed. Wender's hypothesis that an underlying biochemical abnormality and a disorder of reinforcement was the primary deficit in "MBD" children is restated in terms of a disorder of polysynaptic dopaminergic circuits, between prefrontal and striate centres. Wender's notion of a disorder of reinforcement is broadened to include a disorder of planning and correction of behaviour, including capacity for cortical control of automatic instinctual motor programmes. The dopamine hypothesis of Attention Deficit Hyperactivity Disorder (ADHD) is examined from the point of view of differential dose effects of CNS stimulant medications, and theories of neural control. Clinical, animal and neuropharmacological studies are reviewed. Implications of the findings for understanding clinical and side effects in ADHD children of stimulants are discussed.

Animals↗
PubMed1990

Effect of epidermal growth factor on rat pleural mesothelial cell growth.

We recently reported that the growth of normal rat pleural mesothelial cells (RPMCs) is inhibited by conditioned media from either in vivo or in vitro transformed RPMCs. In this study we report that the growth of normal RPMCs is inhibited by epidermal growth factor (EGF). This was demonstrated by using three methods of investigation. Two types of studies were carried out with growing cells. First, cell counts indicated that the number of cells was reduced in EGF-treated cultures when compared with untreated cultures. Second, the percentage of S cells detected by flow cytometry following treatment with EGF was lower than without EGF. In other experiments, incorporation of tritiated thymidine in confluent cells was decreased by EGF treatment, either in the presence or absence of fetal calf serum; these effects were dose dependent and were observed from 2 ng/ml EGF. Lower EGF concentrations did not significantly modify thymidine incorporation when compared with untreated cells. Analysis of 125I EGF binding experiments by the Scatchard method indicated that RPMCs posses EGF receptors (about 10(5) per cell) with low ligand binding affinity (Kd = 1.7 +/- 0.4 nM). These results indicate that EGF might modulate the growth of RPMCs.

Animals↗
PubMed1990

Oral findings in elderly nursing home residents in selected countries. 1.

In order to determine the influence of culture, individual idiosyncrasy, social and economic conditions as well as the importance of past and current dental care on oral health, the oral conditions of 610 patients in seven old age homes were evaluated in four countries: USA, Peru, Argentina and Israel. The patients included in this study were examined by clinicians who had undergone training and calibration sessions. The seven institutions surveyed have a large range of physical facilities, economic levels, and a variety of quantity and quality among medical, dental and ancillary staff. There were marked differences as to philosophy of treatment and scope for the dental care of the residents. A subjective impression by the examiners is that old age home administrators do not regard the dental needs of the residents to be among their higher priorities. Dental care is considered expensive and requires special equipment and exclusive physical space on the institutional premises. Of the 610 residents 419 were women and 191 men, with an average age of 80 years. The mean number of years of schooling was six. Sixty-two percent of the examinees were widowed, 21% were married, 1% single, 2% divorced, and 5% of unknown or undeclared status. The main orodontal characteristic of the population surveyed was partial or full eduentulousness. Of the total population (610 examinees) only three patients possessed a full complement of natural, unrestored teeth. Twelve examinees had 28 unit dentition, partly natural teeth and partly restored with plastic fillings, fixed prostheses, crowns or pontics. Three hundred and one patients (49%) of the examined population were totally edentulous, 249 (41%) wore sets of complete dentures and 52 (8%) did not wear any prosthetic restoration or replacement.

Aged↗
PubMed1990

Oral findings in elderly nursing home residents in selected countries. 2. Soft tissue lesions and denture wearing habits.

This paper demonstrated that 38% of the 610 examinees at seven institutions in four countries have soft tissue lesions. Seventy to eighty percent of the detected lesions were of the erythematous type. This incidence was found at institutions with and without attending dentists, in denture and non-denture users, in dependent and independent patients. Tissue lesions in denture wearers were four times as many as in non-denture wearers. The percentage of inflammatory lesions in both denture and non-denture wearers was considerably higher at institutions with no attending dental personnel when compared with those with dental care facilities. Where patients depended on the staff and/or their relatives for their personal hygiene, a sharp increase in pathological findings was seen when compared to independent dwellers. The nursing staff and the relatives know very little about the oral problems of the elderly residents. There was no uniform policy about telling patients when to wear their removable dentures and patients did not always follow instructions when they were given. Many patients sleep with their upper denture while the lower one is removed for the night. Patients sometimes sleep in the dentures and sometimes remove one or both dentures for varying periods of time. The high percentage of soft tissue lesions and erratic denture wearing habits point to neglect and insufficient oral care toward the geriatric population studied.

Aged↗