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Biomedical subjects

B Ludes

Publications and source records attributed to B Ludes.

At least 91 records · Page 5Linked to original sources
PubMed1994

Application of a simple enzymatic digestion method for diatom detection in the diagnosis of drowning in putrified corpses by diatom analysis.

The reliability and applicability of quantitative and qualitative diatom analysis by an enzymatic digestion method in the diagnosis of drowning of putrified bodies has been evaluated. The authors report the analysis of water and organ samples of 12 immersion cases using light microscopy. This study included control organ samples from the bodies of persons who died from causes other than drowning. Organ samples were treated by both chemical and enzymatic methods, the first one using concentrated nitric acid and the second proteinase K. Diatoms were present in most organ samples of the immersed corpses; no diatoms could be found in the control samples. Our experience was that the enzymatic method seemed to be more convenient in terms of rapidity, safety and environmental protection than chemical digestion. The number of diatoms recovered with both methods was similar. Qualitative and quantitative analysis of both water and organ samples of immersion cases supported the diagnosis of death by drowning in 41.6% of the putrified cases studied. The authors suggest that diatom analysis using enzymatic digestion of organs can be used as a criterion for positive diagnosis of drowning in cases involving putrified bodies.

Brain↗
PubMed1994

Medico-legal investigations of the Airbus, A320 crash upon Mount Ste-Odile, France.

The authors present the medico-legal investigations and identification after the aircrash of the Airbus A320 upon the Mount Sainte-Odile (France). The identification team comprising investigators from the gendarmerie, forensic pathologists, odontologists, and scientists of the Institute from Legal Medecine rapidly retrieved and identified 85 of the 87 victims, with 17 being identified through DNA typing, three through fingerprints and the remaining through dental records and specific physical or X-ray findings. Full autopsies were performed on all fatalities to determine patterns of injury and cause of death. Results lead us to point out the importance of a multidisciplinary team of forensic practitioners especially trained for managing medico-legal investigation in mass disaster and the ability of DNA technology to solve complex identification problems.

Accidents, Aviation↗
PubMed1993

Sex determination of forensic samples: co-amplification and simultaneous detection of a Y-specific and an X-specific DNA sequence.

The detection of restriction fragment length polymorphisms (RFLP) (1) in DNA extracted from forensic samples remains impossible in a significant number of cases due to deterioration and contamination of the biological material and the extremely low quantities of DNA isolated. The polymerase chain reaction (PCR) is a recent and particularly convenient method for analysing and typing very small amounts (10-20 ng) of degraded human DNA. DNA analysis at the level of a few cells present in forensic samples such as bloodstains, semen stains, vaginal swabs and head hair bulbs now appears possible using DNA amplification. A PCR protocol was adapted to simultaneously amplify a Y-specific DNA repeat sequence from the DYZ1 locus and an X-specific DNA repeat sequence from the DXS424 locus. The co-amplified Y-specific DNA fragment (102 bp) and X-specific DNA fragments (181-199 bp) were visualized on an ethidium bromide-stained 4% agarose gel. The male or female type of the amplified DNA extracted from blood samples, bloodstains, semen stains, vaginal swabs, brain tissue and 1, 2, 5, or 10 head hair bulbs was determined.

Base Sequence↗
PubMed1993

Influence of cholesterol derivatives on cytoskeletal organization of human carcinoma cells.

Recent developments of immunotherapeutic approaches have shown that artificial ordering of tumor cell membranes with cholesterol hemisuccinate (CHS) or 25-hydroxycholesterol (25-OH) may significantly enhance the immunogenicity of human renal adenocarcinoma cells. To gain further insight into the molecular mechanism of these sterols, we investigated cytoskeletal modification, which is related to the cell membrane. After treatment of human renal carcinoma cells with these cholesterol (at 10(-6) and 10(-7) M) for 5 days, we observed a disorganization of the submembrane end of the cytoplasmic actin stress fibers by cytofluorescence. The microtubule network was not affected. Thus, in the present study, we found that changes in membrane physicochemical properties impaired the anchorage of actin microfilaments in the plasma membrane of human renal cancer cells. Under the same experimental conditions, such modifications were not observed in normal cells (human fibroblasts) or in human hepatoma cells. We suggest that incubation of cancer cells with these sterols induced a redistribution of the cholesterol-rich membrane microdomains which are linked to the cytoskeleton through submembrane proteins.

Actins↗
PubMed1993

DNA fingerprinting from tissues after variable postmortem periods.

DNA typing is a useful tool in forensic cases for determining the identity of remains of humans who have been dead for various periods of time. DNA fingerprinting can be achieved only if high molecular weight DNA (HMWDNA) is extracted from the tissue samples of the bodies even after a long postmortem delay. Analyses were performed on various tissues collected during forensic autopsies of 24 bodies known postmortem ages. Tissues such as blood and kidney were found to be unsuitable for DNA fingerprinting because of a rapid degradation of the DNA after a period of one week. HMWDNA could be successfully extracted from brain cortex regardless of postmortem age.

DNA Fingerprinting↗
PubMed1992

A report of an international collaborative experiment to demonstrate the uniformity obtainable using DNA profiling techniques.

This paper describes a collaborative exercise intended to demonstrate whether uniformity of DNA profile results could be achieved between different European laboratories. It was shown that this goal can be obtained provided that a common protocol is followed (specifically the use of a common electrophoretic buffer as being the most important parameter). Generally, lower molecular weight loci (with lower molecular weight fragments) such as YNH24 perform better than higher molecular weight loci such as MS43a. The results of the exercise are discussed in relation to the objectives of the European DNA profiling group (EDNAP).

Autoradiography↗
PubMed1992

Detection of drugs in human hair using Abbott ADx, with confirmation by gas chromatography/mass spectrometry (GC/MS).

The authors suggest use of the fluorescence polarization immunoassay (FPIA) technique in evaluation of chronic drug abuse using human hair. Hair was decontaminated in 5 mL of ethanol for 15 min at 37 degrees C and then incubated in 3 mL of 1M sodium hydroxide (NaOH) for 1 h at 100 degrees C. Afterwards, the aliquots were neutralized and analyzed using Abbott ADx for a negative or positive response for the following drugs: benzodiazepines, barbiturates, antidepressants, opiates, cocaine, amphetamine, and cannabis. All the positive samples were confirmed by gas chromatography/mass spectrometry (GC/MS). Only one false positive was detected (caused by interference of a phenothiazine with the antidepressants kit), clearly demonstrating the capability of ADx for toxicological screening of human hair.

Fluorescence Polarization↗
PubMed1992

Evaluation of nicotine and cotinine in human hair.

To validate data on tobacco use, the authors investigated the use of hair samples for quantifying nicotine and cotinine by gas chromatography/mass spectrometry. Hair was taken from 22 nonsmokers and 42 smokers, cut close to the scalp at the back of the head. The hair (about 100 mg from each subject) was incubated in 3 mL of 1N NaOH at 100 degrees C for 1 h. After this, the samples were extracted by diethyl ether. The drugs were separated on a 12-m BP-5 capillary column and detected using selected ion monitoring (nicotine, m/z 84; cotinine, m/z 98). Hair from nonsmokers and smokers contains nicotine and cotinine. Although it is difficult to determine an absolute cutoff level, an amount greater than 2 ng of nicotine per milligram of hair can be used to differentiate smokers from nonsmokers. In the population of nonsmokers, the influence of environmental smoke exposure was noted.

Adolescent↗
PubMed1990

Fly larvae and their relevance in forensic toxicology.

Toxicological analyses on a putrefied cadaver are sometimes difficult to perform because of the absence of blood and urine. In this study, fly larvae, being living material, are proposed as a new medium of investigation in forensic toxicology. Bromazepam and levomepromazine were identified and assayed in the remains of cerebral tissue, in the clavicle of a putrefied cadaver, and in the fly larvae found on and in the corpse.

Aged↗
PubMed1990

Increased immunogenicity of human renal carcinoma cells following treatment with cholesterol derivatives.

Tumor cells isolated from human renal cell carcinoma biopsies were treated with cholesteryl hemisuccinate or 25-hydroxycholesterol and the subsequent changes in their membrane fluidity and capacity to induce skin reactivity in the homologous patient were investigated. Both cholesterol derivatives were found equally efficient in decreasing membrane fluidity when measured by fluorescence polarization of diphenylhexatriene. Using trimethylammonium-diphenylhexatriene, a specific cell surface probe, 25-hydroxycholesterol, appeared much more efficient than cholesteryl hemisuccinate in inducing a membrane rigidification in the carcinoma cells. Cells treated with cholesteryl hemisuccinate induced a strong positive skin reaction compatible with delayed-type hypersensitivity in 54% of the patients, whereas 25-hydroxycholesterol-treated cells were less potent (36% positive skin reactions). Thus, manipulation of the physicochemical state of the membrane of human renal carcinoma cells could increase their immunogenicity in the autologous patient, although this seemed not to be related only to membrane rigidification.

Aged↗
PubMed1990

[Stimulation of antigenicity of renal adenocarcinoma cells].

It was hypothesized that membrane rigidification of tumor cells could enhance the expression of tumor associated antigens (6) For this purpose, we treated in vitro hypernephroma cell with cholesterol hemisuccinate (CHS) or 25-hydroxysterol (250HC) and we evaluated their immunogenicity by skin-tests in 26 patients after radical nephrectomy. The skin-tests were positive in 50% cases with CHS treated cells, and in 35% with 250HC treated cells. The immune responses were characterized as delayed hypersensitivity. However determinations of all membrane fluidity suggested that membrane rigidification was not the unique factor involved. These results could therefore be of clinical interest in the treatment of renal carcinoma by active immunotherapy.

Adenocarcinoma↗
PubMed1989

A fatal ingestion of sparteine and meprobamate: medicolegal and toxicological data.

A case of suicidal overdose from the ingestion of Palpipax (meprobamate and sparteine) is presented. The drugs were quantified in biological fluids and tissues using gas chromatography. The blood concentrations of meprobamate and sparteine were found to be 88.2 and 40.4 micrograms/ml, respectively. Results are discussed in the light of the existing literature.

Acute Disease↗
PubMed1989

Identification and determination of dextromoramide, a nonopiate narcotic.

A method for the identification and quantification of dextromoramide in plasma by GC/NPD is presented. The procedure employs alfentanil as the internal standard and requires no derivatization. After a single-step extraction, analysis is performed on a 3% OV-17 Chromosorb Q glass column. The lower limit of detectability was found to be 2 ng/ml in plasma.

Chromatography, Gas↗