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Biomedical subjects

D Vidal

Publications and source records attributed to D Vidal.

At least 19 recordsLinked to original sources
PubMed1992

Effects of taxol on the macrophage function. Interactions with some immunological parameters.

The effects of Taxol on some immunological parameters were investigated, in vitro, in the murine macrophage cell line J774.1. Mitochondrial dehydrogenase activity and (3H) TdR incorporation were shown to be increased in Taxol treated cells. Likewise, Taxol induced TNF alpha secretion. But Taxol seemed to be a weak inducer of the two interleukins IL-1 and IL-2, since their detection occurred late in the cell culture supernatants.

Alkaloids↗
PubMed1992

Occupational exposure to cocaine involving crime lab personnel.

The possibility of exposure to cocaine as a result of analyzing it or handling material contaminated by it has been a major concern of laboratory personnel. Several different work environments and simulated situations were examined to assess the likelihood of this type of exposure occurring. Urine specimens were collected and evaluated for cocaine and benzoylecgonine using the Syva ETS System (EMIT). Each specimen was analyzed for the two substances using gas chromatography/mass spectrometry (GC/MS). Urine specimens of laboratory-management personnel not working with drug samples showed no trace of cocaine or benzoylecgonine. A urinary benzoylecgonine level of 227 ng/mL was found in the specimen from one narcotics criminalist who was working on a routine case of 2 kilos of cocaine hydrochloride in the Narcotics Laboratory. A maximal urinary benzoylecgonine concentration of 1570 ng/mL was determined in the urine specimen from one narcotics criminalist who was sampling a case containing 50 kilos of cocaine hydrochloride over a period of 3 h. Decreasing the levels of airborne cocaine dust appears to minimize the amount of cocaine absorbed by the criminalists. Gloves, face masks, and goggles prove to be effective in minimizing exposure.

Air Pollution, Indoor↗
PubMed1991

[Peroperative monitoring of the facial nerve in surgery for acoustic neuroma].

This paper reports our experience about intraoperative facial nerve monitoring carried out in 97 patients operated on by a retrosigmoid approach. Intra-operative facial nerve monitoring was performed using a pneumatic sensor which transforms into acoustic signals contractions of facial muscles elicited by mechanical, electrical or thermal stimulations of facial nerve. Long term results showed that a normal facial function (grade I) was achieved in 90.5% of patients, 4 patients were grade II, 2 patients grade III, a total paralysis (grades V and VI) was persistent in 3 patients. Our experience with facial nerve monitoring suggests a modification of the strategy of dissection based upon a preservation of the arachnoid veil and a medial to lateral direction of dissection.

Electric Stimulation↗
PubMed1990

Immunotoxicity testing of mycotoxins T-2 and patulin on Balb/c mice.

The effects of patulin and T-2 toxin were investigated on immunological responses of Balb/c mice. In vitro patulin had a stimulatory effect on splenocytes at lower concentration (1 nM to 10 nM) and strongly inhibited lymphocyte proliferation at higher concentrations (ID50 from 0.02 to 0.24 microM depending on mitogens). In the same experiments T-2 toxin was 100-fold more potent (ID50 from 0.7 to 2 nM). In vivo studies on immunity were performed in mice receiving Bordetella pertussis antigens and keyhole limpet haemocyanin. Patulin significantly reduced delayed type hypersensitivity to B. pertussis antigen and did not reduce anti-KLH antibody production. T-2 toxin had no effect on delayed type hypersensitivity and reduced anti-KLH antibody production. Splenocytes were harvested in mice with or without antigen stimulation to assess mitogenic responses. Patulin generally increased splenocyte proliferation, therefore T-2 toxin effect depended on the immunological status of mice and on the dose injected. At the lower doses (0.8 mg/kg), T-2 toxin enhanced responses to mitogen, but at the greater dose (1.6 mg/kg) T-2 toxin enhanced responses to mitogen of antigen stimulated mice and decreased responses of unstimulated mice.

Animals↗
PubMed1989

In vitro and in vivo toxicity of T-2 toxin, a Fusarium mycotoxin, to mouse peritoneal macrophages.

The effects of T-2 toxin on mouse peritoneal macrophages were investigated. Scanning electron microscopy of macrophages treated in vitro with T-2 toxin revealed retraction of pseudopodia. Protein synthesis was inhibited after in vitro contact with T-2 toxin but was not affected 24 h after injection of a sublethal dose of toxin into mice. There was reduction in the phagocytosis of Pseudomonas aeruginosa when macrophages were exposed in vitro to T-2 toxin and when mice were injected with T-2 toxin. Clearance of colloidal carbon was not modified after T-2 toxin injection, whereas spleen weight was decreased 24 h after T-2 injection. T-2 toxin enhanced the mortality of mice infected with Salmonella typhimurium C5S when it was administered 24 h prior to oral challenge with the bacterium.

Animals↗
PubMed1989

[Programming VTIM physiologic pacemakers (evoked QT)].

Seventeen VTIM pacers were implanted in seventeen patients. Average follow up were 16.7 months. This paper concerns TX track and TX on modes only. Sensing window period and slope, which determine the rate response, must be programmed carefully. Potential competitive rhythms, severe ventricular arrhythmias or inadequate rate response to physical stress may potentially develop under inadequate programming. Consequently, it is advisable to program the sensing window 20-25 ms longer than the QTE max (at LRL) and the slope at 100% of the whole value. No complications were detected. Figures 1, 2 and 3 show examples of competitive rhythms without heart stimulation and unsensed beats by abnormally long programmed SW values. When properly shortened, this interval allows proper measurement of the Stim.-T and no competitive rhythm, during almost the same spontaneous rhythm. This system fulfills the major conditions for pacing the heart: rate adaptation to neurohormonal release, to physical stress and operative mode as a close-loop system during the recovery period.

Adaptation, Physiological↗
PubMed1988

Influence of metabolic and physical factors on production of diacetoxyscirpenol by Fusarium sambucinum Fuckel.

Fusarium sambucinum Fuckel 8099-1 was grown on Czapek-Dox peptone-supplemented medium at 15 degrees C for 14 days, and the cultures were investigated for diacetoxyscirpenol (DAS) production by liquid-liquid extraction and gas chromatography. The addition of 150 mg of sorbic acid, a tricarboxylic acid cycle inhibitor, per liter stimulated both fungal growth and DAS production. Among the beta-hydroxy-beta-methylglutaryl coenzyme A precursors tested, isovaleric acid completely inhibited fungal growth and DAS production, ethyl isovalerate did not support a significant increase in DAS production, and L-leucine partially inhibited DAS production, showing that L-leucine and isovaleric acid catabolisms do not induce trichothecene biosynthesis. Solid particles (cork powder) were necessary for DAS production in stationary cultures but did not influence DAS production in shaken cultures. Shaking strongly stimulated DAS production and fungal growth.

Acyl Coenzyme A↗
PubMed1987

Early inhibition of natural and interferon-activated killers in endometrial cancer patients treated with local radiotherapy.

The present study was aimed at comparing the effect of clinical staging and radiotherapy on natural killer (NK) and interferon-activated killer (IAK) cell activity in a group of endometrial cancer patients receiving a total dose of 5,000 to 8,000 rads. We report that when compared to age-matched women, a significantly higher number and percentage of patients show low NK and IAK cell activity. At diagnosis, diminished NK activity was seen in about 20% of the patients, while IAK activity was low in 49% of these patients. There was no correlation between these deficiencies and the grade or stage of the disease. In contrast, radiotherapy induced deleterious effects on both populations of NK and IAK cells. These deleterious effects were more pronounced in patients showing a low level of spontaneous NK activity. In an attempt to understand better the mechanism by which the presence of cancer itself and/or radiotherapy affects these activities, we studied in greater detail changes in peripheral blood T-cell numbers and subsets. Before radiotherapy, all lymphocyte counts were within the normal range. In contrast, after radiotherapy the absolute numbers of all T-cell subsets were significantly decreased in the majority of the patients tested, OKT4+ cells being the most radiosensitive and Leu 7+ cells the most radioresistant.

Female↗
PubMed1987

Production and characterization of monoclonal antibodies showing a different spectrum of reactivity to human breast tissue.

We have generated three hybridoma-producing monoclonal antibodies (MAs) that show a different spectrum of reactivity to human mammary tissues. Two of these antibodies, 1F10B4 and 1F10G2, recognize a cytoplasmic determinant highly expressed in most of the primary and metastatic breast carcinomas studied, and weakly (or not at all) in normal breast and nonbreast tissues. 3C6F9 detected a surface determinant common to both normal and neoplastic mammary epithelium. Five hundred hybridomas were obtained from the fusion of NS-1 myeloma cells with spleen cells of mice hyperimmunized with the well-characterized human breast carcinoma cell line BT-20. After the initial screenings and clonings, three monoclonal antibodies (1F10B4, 1F10G2, and 3C6F9) showing a restricted range of reactivity were selected for further investigation. These three antibodies recognized a panel of neoplastic mammary cell lines; however, the degree of reactivity could not be correlated to any of the various characteristics of these epithelial cell lines. Moreover, immunofluorescence analysis of acetone-fixed cryostat section showed that 1F10B4 and 1F10G2 recognize the vast majority of the 37 primary and metastatic breast cancers tested, binding strongly to 47% and 67% of them respectively. Only one of the primary carcinomas was not recognized by 1F10B4. On the other hand, these two MAs reacted weakly or not at all with normal breast and nonbreast tissues showing only few focal reactivities with the luminal pole of some ducts of the breast; very weak staining in renal tubular epithelial cells, in few keratinocytes and epithelial cells lining some sebaceous glands in the skin; and a moderate staining in biliary ducts of the liver. All mesenchymal structures including smooth and striated muscle tissues, lymph nodes, and connective tissue were negative. On the other hand, 3C6F9 recognized a more limited number of human mammary tumors and reacted with normal ductal epithelium in the breast and with nonbreast tissues. Because of their wide spectrum of reactivity with breast cancer cells and restricted recognition of normal mammary tissues, their cytoplasmic localization, and their heterogeneous distribution within a single neoplasm, 1F10B4 and 1F10G2 are now being used to characterize antigenic phenotypes of tumor-associated antigens in retrospective studies performed on conventional formalin-fixed, paraffin-embedded human mammary carcinomas.

Animals↗
PubMed1985

Rapid large-scale purification of plasmid DNA by medium or low pressure gel filtration. Application: construction of thermoamplifiable expression vectors.

This paper describes a new method of plasmid DNA purification which is fast and reliable enough for most purposes in recombinant DNA technology. The present method does not require the use of toxic chemicals such as phenol or ethidium bromide, costly ultracentrifugation procedures or other processes which can modify the supercoiled structure of the plasmids, such as adsorption on glass fiber. This method is based on the principle of gel filtration chromatography, at low pressure (1 bar) or medium pressure (between 5 and 10 bars), using Sephacryl S1000 or Superose 6B. It permits recovery of plasmids: in preparative quantities (from 300 micrograms to 4 mg), exempt from RNA, DNA and protein contamination, and suitable for various common genetic engineering procedures immediately after purification. To test the reliability of the technique as well as the degree of purification, the plasmids were used to construct thermoamplifiable vectors, carrying the lacUV5 promoter and the 5' end of the beta-galactosidase gene with a single EcoR1 site in each of the three possible translational phases. This set of vectors is designed for the expression of foreign genes as hybrid proteins in Escherichia coli.

Chromatography, Gel↗
PubMed1984

[Thyroid nodules. Diagnostic value of fine-needle biopsy. 159 surgical patients].

Between October 1980 and March 1983 we explored 269 patients who had one or several thyroid nodules with low or normal technetium 99 uptake. Each palpable nodule was aspirated 1 to 3 times, using a fine 21 G2 needle, and the aspirates were immediately spread on glass-plates and kept in alcohol-ether. After staining by the Harris- Shor method, all plates were examined by the same cytologist. Biopsies were unassessable in 50 patients (18%), mainly because they were entirely made up of red cells. Sixty patients did not undergo surgery. In the 159 patients operated upon, cytology was compared with histology which showed 139 benign and 20 malignant nodules. In 5 histologically benign nodules, cytology had shown nuclear abnormalities or enlarged cells suggestive of malignancy (false-positive results: 3.5%). Among 5 nodules diagnosed as benign at cytology, there were 2 papillary microcarcinomas , 2 to 4 mm in diameter, the course of which is little known, 1 well differentiated vesicular cancer extremely difficult to distinguish from vesicular adenoma, and 2 papillary cancers. Fine needle biopsy cytology is a harmless procedure, but it requires considerable experience on the part of cytologists. We consider that it should be performed in all cases of thyroid nodule, either to help in deciding whether or not to operate, or to guide the surgeon in deceding whether or not to operate, or to guide the surgeon in his operative strategy.

Biopsy, Needle↗
PubMed1984

[Effect of temperature on diacetoxyscirpenol production and on sporulation in a liquid culture of Fusarium sambucinum].

F. sambucinum grown for 14 days on peptone supplemented Czapek medium produced higher amount of diacetoxyscirpenol at + 15 degrees C than at + 25 degrees C or at temperature kept successively at + 15 degrees C (day) and + 5 degrees C (night). There was no correlation between the spores number and the toxin level, but toxin synthesis began only with sporification and then continued until the 14th day.

Fusarium↗
PubMed1983

[Experimental infection of mice by Salmonella typhi inoculated orally: influence of immunosuppressive therapy].

Various immunosuppressive treatments were used in order to induce a Salmonella typhi infection in mouse by oral route. Neither low protein diets nor administration of mucin, iron, streptomycin or silica could modify animal's sensitiveness, but, cyclophosphamide injections enhanced lethal effect of bacteria, while silica increased the number of bacteria in the blood and the spleen.

Administration, Oral↗