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Biomedical subjects

K Michel

Publications and source records attributed to K Michel.

At least 37 records · Page 2Linked to original sources
PubMed2001

Quercetin 3,3',4'-tri-O-beta-D-glucopyranosides from leaves of Eruca sativa (Mill.).

Three new quercetin 3,3',4'-tri-O-beta-D-glucopyranosides isolated from leaves of Eruca sativa (Mill.) were identified as quercetin 3,3',4'-tri-O-beta-D-glucopyranoside, quercetin 3'-(6-sinapoyl-O-beta-D-glucopyranosyl)-3,4'-di-O-beta-D-glucopyranoside and quercetin 3-(2-sinapoyl-O-beta-D-glucopyranosyl)-3'-(6-sinapoyl-O-beta-D-glucopyranosyl)-4'-O-beta-D-glucopyranoside. The structures were established by one- and two-dimensional 1H and 13C NMR spectra as well as b

Brassicaceae↗
PubMed2001

Hermes-mediated germ-line transformation of the Mediterranean fruit fly Ceratitis capitata.

We report the use of the Hermes transposable element for germ-line transformation of the Mediterranean fruit fly, Ceratitis capitata. Hermes was able to genetically transform this insect at an estimated frequency between 0.6 and 1.1%, which is comparable to the transformation frequencies obtained for this species when using other transposable elements. Hermes integrates into the medfly genome by a cut-and-paste mechanism and the sequences integrated into the genome are delimited by the terminal nucleotides of the Hermes inverted terminal repeats. Integration resulted in the generation of 8 bp target site duplications, the sequences of which conformed to the target site duplications generated by hAT element transposition in insects. The Hermes element is one additional genetic tool that can be deployed in manipulating and characterizing the medfly genome.

Animals↗
PubMed2001

Neurotransmitter coding of enteric neurones in the submucous plexus is changed in non-inflamed rectum of patients with Crohn's disease.

Knowledge of the neurochemical coding of submucosal neurones in the human gut is important to assess neuronal changes under pathological conditions. We therefore investigated transmitter colocalization patterns in rectal submucosal neurones in normal tissue (n=11) and in noninflamed tissue of Crohn's disease (CD) patients (n=17). Neurone-specific enolase (NSE), choline acetyltransferase (ChAT), vasoactive intestinal polypeptide (VIP), substance P (SP), nitric oxide synthase (NOS) and calcitonin gene-related peptide (CGRP) were detected immunohistochemically in whole-mount preparations from rectal biopsies. The neuronal marker NSE revealed no differences in the number of cells per ganglion (controls 5.0; CD 5.1). Four cell populations with distinct neurochemical codes were identified. The sizes of the populations ChAT/VIP (58% vs. 55%), ChAT/SP (8% vs. 8%), and ChAT/- (22% vs. 22%) were similar in control and CD. The population VIP/- was significantly increased in CD (12% vs. 2% in controls). Unlike in controls, all NOS neurones colocalized ChAT in CD. Thickened CGRP-fibres occurred in CD. We identified neurochemically distinct populations in the human submucous plexus. The increase in the VIP/- population, extensive colocalization of ChAT and NOS and hypertrophied CGRP fibres indicated adaptive changes in the enteric nervous system in noninflamed rectum of CD patients.

Adolescent↗
PubMed2000

Projections and neurochemistry of interneurones in the myenteric plexus of the guinea-pig gastric corpus.

Recently, motor neurones of the myenteric plexus innervating the muscle layers or the mucosa have been identified in the guinea-pig stomach. We applied the neuronal tracer DiI (1,1'-didodecyl-3,3,3', 3'-tetramethylindocarbocyanine perchlorat) onto myenteric ganglia in order to identify populations of interneurones in the myenteric plexus of the guinea-pig stomach. The tracing was combined with the immunohistochemical detection of calbindinD28k (CALB), choline acetyltransferase (ChAT), neuropeptide Y (NPY) and 5-hydroxytryptamine (serotonin) (5-HT) and the results were compared to the neurochemical coding of target specific motor neurones. Long projecting ( approximately 5.4 mm) ChAT/CALB/+/-5-HT-, nitric oxide synthase (NOS)/CALB- and short projecting ( approximately 1.1 mm) ChAT/NPY-neurones were identified as descending interneurones. CALB positive ascending interneurones contained ChAT but rarely 5-HT (code: ChAT/CALB). This study identified ascending and descending interneurones in the gastric myenteric plexus and revealed the neurochemical coding of some of the interneurone populations.

Animals↗
PubMed2000

Recommended care for young people (15-19 years) after suicide attempts in certain European countries.

Data on recommended care for young people aged 15-19 years after attempted suicide from nine European research centres during the period 1989-1992 were analysed in terms of gender, history of previous suicide attempt and methods used. Altogether 438 suicide attempts made by 353 boys and 1,102 suicide attempts made by 941 girls were included. Analyses of the total data from all centres showed that young people with a history of previous suicide attempt and those using violent methods had significantly higher chance of being recommended aftercare than first-time attempters or those choosing self-poisoning. There were no significant differences of being recommended care between genders. Logistic regression analyses of the material were performed and the results were similar. Both having previous attempted suicide (odds ratio 2.0, 95% CI 1.53-2.61) and using "hard" methods (odds ratio 1.71, 95% CI 1.49-1.96) were significantly associated with increased possibility of being recommended aftercare. When individual centres were analysed, large disparities of recommended care after suicide attempts were found and there were no uniform criteria of recommending care for young suicide attempters in Europe.

Adolescent↗
PubMed2000

Methods used for parasuicide: results of the WHO/EURO Multicentre Study on Parasuicide.

BACKGROUND: National suicide statistics show remarkable differences in the frequencies of various methods used for completed suicide. The WHO/EURO Multicentre Study on Parasuicide makes possible for the first time an international comparison of the frequencies of methods used in attempted suicide, because the data are based on geographical catchment areas of medical institutions. METHOD: Ongoing standardized monitoring of attempted suicide in all medical institutions serving the catchment areas was performed in 14 centres in 12 European countries. The data analysis is based on 20,649 events involving 15,530 persons, recorded between 1989 and 1993. RESULTS: The comparison of rates per 100,000 shows striking differences between the centres. The highest rates for drug overdoses were found for female attempters in Oxford (347/100,000), Helsinki (238/100,000) and Stockholm (221/100,000). Guipuzcoa had the lowest rates (61/100,000). The differences were most prominent in the age group 15-24, with outstanding rates for women in Oxford (653/100,000), which was mainly due to the frequent use of analgesics. Szeged had outstandingly high rates for pesticides and solvents. In some centres the use of multiple methods was frequent. CONCLUSIONS: There is a need, especially for areas with high frequencies for certain methods, to understand the factors involved and to develop new and specific prevention projects and to monitor their effects. The WHO/EURO Multicentre Study on Parasuicide has proved to be a useful and reliable instrument for continuous monitoring of trends in parasuicide.

Catchment Area, Health↗
PubMed2000

Projections and neurochemical coding of motor neurones to the circular and longitudinal muscle of the guinea pig gastric corpus.

The present study identified projection and neurochemical coding patterns of intrinsic circular (CMN) and longitudinal muscle motor neurones (LMN) in the guinea pig stomach by using the retrograde tracer DiI (1,1'-didodecyl-3,3,3',3'-tetramethylindocarbocya-nine perchlorate) in combination with the immunohistochemical demonstration of choline acetyltransferase (ChAT), enkephalin (ENK), neuropeptide Y (NPY), nitric oxide synthase (NOS) and substance P (SP). Populations of LMN and CMN had similar neurochemical coding and a clear polarity of projection. Taking all DiI-labeled cell bodies as 100%, ascending pathways exhibited the coding ChAT/- (CMN:14.7%/LMN: 18.3%), ChAT/ENK (15.7%/10.1%), ChAT/SP/+/-ENK (19.2%/16.4%), or ChAT/NPY (4.4%/7.6%); descending pathways had the coding NOS/- (13.8%/16.9%), NOS/NPY (9.9%/17%), NOS/ENK (4.4%/1.2%) or NOS/NPY/ENK (13.0%/5.5%). The relative contributions of these populations were not different between CMN and LMN. However, target-specific projection patterns were revealed: most LMN (82%) had longitudinal whereas most CMN (58%) had circumferential projection preferences. The results indicate that gastric circular and longitudinal muscle layers are innervated by ascending excitatory and descending inhibitory pathways in the myenteric plexus. The projection patterns of CMN and LMN were different and followed the orientation of the muscle layers. It is suggested that the specific muscle motor pathways in the gastric myenteric plexus coordinate the reflex-mediated phasic and tonic activity of gastric muscle layers.

Animals↗
PubMed2000

An exercise in improving suicide reporting in print media.

This study was conducted to support the publication of guidelines for media reporting on suicide. First, quantitative and qualitative aspects of suicide reporting in Swiss print media were surveyed over a time span of 8 months. The results were presented at a national press conference, and written guidelines for suicide reporting were sent out to all newspaper editors. The results of the survey and the guidelines were discussed in a personal meeting with the Editor-in-Chief of the main tabloid. After the publication of the guidelines a second, identical survey was conducted. The main variables regarding frequency, form, and content of the newspaper reports before and after the press conference were compared. The number of articles, on the one hand, increased over the 3 years between the first and second survey, but the quality of reporting clearly improved on the other. The personal contact with the editor of the tabloid was probably the most effective means of intervention.

Guidelines as Topic↗
PubMed2000

Green fluorescent protein as a genetic marker in transgenic Aedes aegypti.

We report here the use of the enhanced green fluorescent protein (EGFP) from the jellyfish, Aequorea victoria, as a genetic marker for the genetic transformation of mosquitoes. The EGFP gene, under the control of the actin5C promoter of Drosophila melanogaster was inserted into the Hermes transposable element. Preblastoderm embryos of a wild-type strain of the yellow fever mosquito, Aedes aegypti, were microinjected with this plasmid, together with a helper plasmid containing the Hermes transposase placed under the control of the D. melanogaster hsp70 promoter. Somatic EGFP expression was observed during early instars in approximately one-half of all G0 individuals. Two G1 individuals arising from a G0 female displayed high levels of EGFP gene expression during all stages of development. EGFP was transmitted in a Mendelian fashion to the G2 and G3 generations and molecular analysis confirmed the presence of the Hermes[actin5C:EGFP] gene in these insects. These results clearly demonstrate that EGFP can be used as an effective genetic marker in wild-type Ae. aegypti and most likely in other mosquito species as well.

Aedes↗
PubMed2000

A cross-cultural study of suicide intent in parasuicide patients.

As part of the WHO/EURO Multicentre Study on Parasuicide, the level of suicide intent among female and male parasuicide patients from various European regions was compared. From nine regions, a total of 1,212 parasuicide patients, 752 females and 460 males, were included in the study. Although some statistical significant differences in level of suicide intent between the regions and genders were found, the effect sizes of these relationships were so small that the differences have neither theoretical nor practical significance. As far as level of suicide intent is concerned, the WHO study has succeeded in recruiting a relatively homogeneous group of self-harming patients across borders of region, culture, and country.

Adolescent↗
PubMed1999

Immunohistochemical evidence for the presence of calbindin containing neurones in the myenteric plexus of the guinea-pig stomach.

Using immunohistochemistry we studied the presence of calbindin in myenteric neurones of the guinea-pig stomach. A rabbit anti recombinant rat calbindin-D28k (CALB) stained 12, 12 and 25% of all myenteric neurones in the fundus, corpus and antrum, respectively. A rabbit anti recombinant human CALB stained 4, 4 and 16%, respectively. A mouse monoclonal antibody against the chicken intestinal CALB showed no labelling. In all regions most calbindin neurones were additionally choline acetyltransferase (ChAT) positive while only a small proportion exhibited nicotinamide adenosine dinucleatide phosphate (NADPH)-diaphorase-activity. Numerous calbindin-positive varicose nerve fibres were present within myenteric ganglia, rarely detectable in the muscle layers and virtually absent in the mucosa. This study demonstrated that a supopulation of cholinergic myenteric neurones in the stomach contain calbindin and suggested that many of these neurones fulfil interneuronal tasks.

Animals↗
PubMed1999

The enteric nervous system: region and target specific projections and neurochemical codes.

The goal of this report is to summarise the current knowledge on the projection pathways of enteric neurones innervating the muscle and mucosa in different regions of the gut. Combination of neuronal tracing, immunohistochemical and electrophysiological methods has allowed researchers to gain insight into the enteric hardwiring of specific target tissue in the gut. A polarised innervation pattern of the circular muscle was demonstrated for the stomach fundus/corpus and the ileum with descending pathways being primarily nitrergic while ascending pathways were primarily cholinergic. This characteristic hardwiring is thought to set in part the functional basis for peristalsis. A similar polarised innervation pathway was found for the enteric innervation of the mucosa in the stomach and large intestine but not in the small intestine. In both the stomach (myenteric neurones) and in the proximal and distal colon (submucosal neurones), ascending pathways to the mucosa are primarily cholinergic while descending pathways are primarily non-cholinergic. In the colon, results suggest that activation of both pathways induces a cross potentiation of cholinergic and vasoactive intestinal polypeptidergic mediated secretion. Furthermore, a large population of myenteric neurone s projecting to the mucosa in the small and large intestine are probably intrinsic primary afferent neurones sensitive to mechanical as well as chemical stimuli.

Animals↗
PubMed1999

Attempted suicide and major public holidays in Europe: findings from the WHO/EURO Multicentre Study on Parasuicide.

OBJECTIVE: The aim of the study was to examine the relationship between suicide attempts and major public holidays in Europe. METHOD: The analysis was based on data on 24 388 suicide attempts by persons aged 15 years or older in the period 1989-1996. Data from 13 centres (representing 11 countries) participating in the WHO/EURO Multicentre Study on Parasuicide were analysed. The analysis of the fluctuation of suicide attempts around public holidays was based on the daily number of suicide attempts for each centre. For each day in the period under examination a mean number of suicide attempts (mu) was calculated. The analysis was based on the assumption that the data followed a Poisson distribution. The observed number of daily suicide attempts was compared with the expected number of attempts. A multiplicative model for the expected number in each centre was developed. RESULTS: Before Christmas there were fewer suicide attempts than expected, and after Christmas there were approximately 40% more attempts than expected. In addition, more attempts than expected were registered on New Year's Day. In countries where people have the day off work on Whit Monday there were significantly fewer attempts during the 3 days before, but where Whit Monday is a normal working day significantly fewer attempts occurred on the Monday to Wednesday after Whit Sunday. CONCLUSION: There appears to be a transposition of a significant number of suicide attempts from before (and during) a major public holiday until after it. The division of holidays into non-working and working days showed that a 'holiday effect' could only be found around major public holidays, particularly Christmas, Easter and Whitsun. These findings support the theory of the 'broken-promise effect' for major public holidays.

Adolescent↗
PubMed1999

Physical illness and parasuicide: evidence from the European Parasuicide Study Interview Schedule (EPSIS/WHO-EURO).

OBJECTIVE: The aim of this research was to identify psychosocial characteristics which might predict future suicidal behavior in parasuicidal subjects in Europe. METHOD: The interview utilized for the survey (European Parasuicide Study Interview Schedule--EPSIS) was administered to 1269 parasuicides aged fifteen years and over, within one week of hospital admission after a suicide attempt, and is part of a longitudinal multicenter study. EPSIS included a brief medical questionnaire, scales rating depression, hopelessness, self-esteem, suicide intention, questions on sociodemographic characteristics, an interview on life events and social support, a description of the parasuicidal act, and an evaluation of factors precipitating the index parasuicide. RESULTS: Physical illness proved to be very frequent among suicide attempters. One in two subjects suffered from an acute, chronic, or chronic disorder in relapse at the time of the parasuicide. Subjects with a physical illness were significantly more depressed, particularly subjects from the intermediate age band and ones affected by a chronic physical disease in relapse. Forty-two percent of patients with physical illness rated their somatic problem as a factor precipitating the attempt and 22 percent judged it to be major one. Furthermore, subjects with physical illnesses considered psychiatric symptoms and disorders to be relevant factors in triggering suicidal behavior, to a greater extent than non-sufferers. The importance of physical illness in contributing to suicidal behavior increased with advancing age. CONCLUSIONS: More careful attention to somatic conditions and their subjective implications would probably augment chances of effectively preventing suicide.

Adolescent↗
PubMed1999

Synchronous RCC and TCC of the Kidney in a Patient With Multiple Recurrent Bladder Tumors.

Development of concomitant renal TCC and RCC is an uncommon occurrence, yet many interesting issues can be addressed with this model. The possibility of misdiagnosing a renal TCC for an RCC, the options and importance of treating a retained ureteral stump after performing a radical nephrectomy for a renal TCC, and the risk of developing lower tract TCC in patients with upper tract TCC are some of the issues raised in this case review.

Case Reports↗
PubMed1998

Highly efficient and consistent gene transfer into dendritic cells utilizing a combination of ultraviolet-irradiated adenovirus and poly(L-lysine) conjugates.

Dendritic cells (DCs) are capable of presenting tumor-associated antigens and subsequently play an essential role in T-cell activation. The aim of this study was to develop an efficient method for gene transfer into DCs. These genetically transduced DCs can then be used as potent inducers of specific cell-mediated immune response. When compared with physical methods for gene transfer (lipofection and calcium phosphate precipitation), adenovirus (AdV) vectors proved to be highly efficient for gene transfer into DCs. To overcome concomitant AdV gene expression and potential immunogenicity, AdVs were irradiated with UV. The UV dose was optimized to block AdV transcription without altering AdV receptor binding and endocytosis capacity. We subsequently used a polycationic amino acid compound, poly(L-lysine), to conjugate the irradiated AdVs to transgenes. The resulting complexes were found to mediate a highly efficient transfer of transgenes into DCs, without concomitant expression of AdV gene products. Low titers of irradiated AdVs were sufficient for a consistent gene transfer into DCs. This is the first study to demonstrate efficient, consistent, and practical gene transfer using an UV approach to irradiated AdV-poly(L-lysine) conjugates and should be useful for the development of DC-based tumor vaccine therapies.

Adenoviridae↗
PubMed1998

(Latent) transforming growth factor beta in liver parenchymal cells, its injury-dependent release, and paracrine effects on rat hepatic stellate cells.

Cultured parenchymal liver cells (PC) were recently recognized to contain (latent) transforming growth factor beta (TGF-beta) while the expression of TGF-beta mRNA remains controversial. This study was designed to analyze PC in different microenvironments (liver in situ, highly purified, isolated, and cultured PC) regarding the qualitative and quantitative content of mature and latent TGF-beta protein (immunostainings, enzyme-linked immunosorbent assay [ELISA], and enzyme-labeled fluorescence [ELF] technique). The results were compared with its gene expression (reverse-transcription polymerase chain reaction [RT-PCR]). In all microenvironments, PC contained latent TGF-beta, which was partially activated after cell isolation and culture. The amount of total TGF-beta (mature plus latent) of latency-associated peptide (LAP) and of latent TGF-beta binding protein (LTBP) were shown to decrease during culture. In contrast, TGF-beta2 and TGF-beta3 mRNA and LTBP-1 and -3 mRNA expression were first detectable after culture. Permeabilization of cell membranes in whole liver and of isolated PC with streptolysin O or carbon tetrachloride, respectively, released TGF-beta, a part of which was integrated in the large latent complex as estimated by analytical gel filtration chromatography. The TGF-beta released by damaged PC induces paracrine effects on hepatic stellate cell cultures. It stimulates hyaluronan synthesis and antagonizes the effect of mitogenic factor(s) of PC on [3H]thymidine incorporation. The results strongly suggest that the main part of hepatocellular TGF-beta is not generated by de novo synthesis but from uptake into the liver in vivo. The immunodetection of preexisting mature TGF-beta after isolation of the cells is probably caused by intracellular activation of latent TGF-beta. The injury-dependent discharge of TGF-beta from PC might be an important mechanism for initiation and perpetuation of various forms of chronic human liver diseases.

Animals↗