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Biomedical subjects

M Peters

Publications and source records attributed to M Peters.

At least 271 records · Page 15Linked to original sources
PubMed1994

Impaired fibrinolysis in the hemolytic-uremic syndrome of childhood.

Thrombotic obstruction of glomerular capillaries causes acute renal failure in patients with hemolytic-uremic syndrome (HUS). Recanalization of occluded vessels normally occurs by activation of the endogenous fibrinolytic system, mediated by plasminogen activators, which are stored and synthesized in the endothelial cells. However, endothelial injury is considered the primary event in the pathogenesis of HUS, and this may result in impaired fibrinolysis. In five children with HUS we performed a prospective study of plasminogen activator activity and two plasminogen activator antigens: tissue-type plasminogen activator and urokinase-type plasminogen activator before and after intravenous desmopressin. Plasminogen activator inhibitor type-1 antigen was also studied. In the acute stage of HUS plasminogen activating activity was low, in spite of elevated levels of total plasminogen activator antigens. This decrease of plasminogen activating activity was due to high levels of the plasminogen activator inhibitor. Improvement of fibrinolysis paralleled recovery from HUS. We conclude that decreased fibrinolysis is an important pathophysiologic feature of HUS.

Adolescent↗
PubMed1994

Right-handers and left-handers show differences and important similarities in task integration when performing manual and vocal tasks concurrently.

For a sample of 73 consistent left-handers, 46 inconsistent left-handers and 65 right-handers, reciprocal interactions between unimanual or bimanual tasks and concurrent reading tasks were shown to be a complex function of task characteristics and sample composition. The suggestion that subgrouping of left-handers [Hellige and Key, Cerebral Control of Speech and Limb Movements, North Holland, Amsterdam, 1990] influences task interactions in left-handers was borne out. Both manual and vocal performance were measured. The effects of the vocal task on the manual task were variable for groups and conditions, but an important common trend emerged: all handedness groups showed the same robust effect: vocal task performance was better when the right hand performed the manual task. Finally, speaking rate increased and tapping rate decreased during concurrent single hand tapping [cf. Hiscock, Brain Cognit. 1, 119-131, 1982]; and there was an opposite effect with concurrent bimanual tapping. The results favour a task integration model rather than an interference in cerebral functions space model.

Adult↗
PubMed1994

Biomagnetic methodologies for the noninvasive investigations of the human brain (MAGNOBRAIN).

Magnetoencephalography (MEG) non-invasively infers the distribution of electric currents in the brain by measuring the magnetic fields they induce. Its superb spatial and temporal resolution provides a solid basis for the 'functional imaging' of the brain provided it is integrated with other brain imaging techniques. MAGNOBRAIN is an applied research project that developed tools to integrate MEG with MRI and EEG. These include: (1) software for MEG oriented MRI feature extraction; (2) the Brain Data Base (BDB) which is a reference library of information on the brain used for more realistic and biologically meaningful functional localisations through MEG and EEG; and (3) a database of normative data (age and sex matched) for the interpretation of MEG. It is expected that these tools will evolve into a medical informatics environment that will aid the planning of neurosurgical operations as well as contribute to the exploration of mental function including the study of perception and cognition.

Brain↗
PubMed1994

Infection of murine fetal brain cell cultures with Listeria monocytogenes.

The uptake of Listeria monocytogenes by different brain cells was studied in primary dissociated brain cell cultures derived from murine fetuses. In respect to the supposed intraaxonal migration of Listeria monocytogenes in the pathogenesis of listeric focal brain stem encephalitis, it was examined whether the bacterium was internalized by neurons. Infection rates of distinct cell types were determined by double immunofluorescence with antibodies against cell type-specific markers and the bacterial pathogen. Because of the changing composition of the cultures and time-dependent expression of the oligodendrocyte marker galactocerebroside (GC), infections were carried out on day 4, 6, 8, and 15 in vitro. Listeria monocytogenes was detected predominantly within macrophages. Astrocytes, oligodendrocytes, and fibronectin-expressing cells were infected to a lesser extent. The lowest rates of infection were observed in neurons. A tropism of Listeria monocytogenes for neurons was not detected in vitro.

Animals↗
PubMed1994

When can attention not be divided?

Humans can guide simple concurrent and seemingly independent movements of digits between hands, but it is shown here that they find it impossible to do this with digits within a hand. This inability demonstrates a basic characteristic of the relation between attention and the control of the skeletal musculature. Mechanisms that are available to provide the illusion of concurrent and independent guidance of separate movements between hands are not available within a single-hand control system. There is no reason to believe that the inability to divide focal attention in the guidance of two concurrent controlled activities, as exemplified in the example of within-hand movements, does not also extend to nonmotor processes.

Journal Article↗
PubMed1994

Evaluation of a device to exercise hip extensor muscles in children with cerebral palsy: a clinical and field study.

This research includes the effectiveness of a tricycle (hip extensor tricycle) designed to isolate and exercise the hip extensor muscles in children with cerebral palsy. Five children diagnosed with cerebral palsy were given hip extensor tricycles for home use during an 8-week test period. The hip extensor strength and gait pattern of the subjects were recorded at 2-week intervals. Additional recorded information included the time and duration of subject use and a parent evaluation that noted subjective physical and psychological improvements. A panel of experts judged that the gait patterns of four subjects improved during the course of the study. There was an assignable cause for the lack of improvement in the fifth subject. The results of the strength testing were found to be inconclusive. The subjects used the device on a regular basis and enjoyed doing so. Parent evaluations indicated that the use of the hip extensor tricycle improved the subjects' physical condition, coordination, sense of accomplishment, and self esteem. It is recommended that future research implement a longer test period along with improved hip extensor strength measurement methods and focus on improvements in evaluation of gait and physical condition.

Cerebral Palsy↗
PubMed1994

Sources of stress for nurse practitioners.

The purpose of this study was to identify perceived stressors and manifestations of stress in nurse practitioners practicing in Missouri and California. The greatest sources of stress reported by the entire sample (N = 80) were in the categories of time demands and role restrictions. Missouri nurse practitioners found role restriction problems significantly more stressful than California nurse practitioners did. Manifestations of stress fell within the norms of non-psychiatric adults on the Symptom Check List 90-R.

Adult↗
PubMed1994

Effects of a computerised protocol management system on ordering of clinical tests.

OBJECTIVE: To assess the effects of a computerised protocol management system on the number, cost, and appropriateness of laboratory investigations requested. DESIGN: A before and after intervention. SETTING: A supraregional liver unit in a teaching hospital. PATIENTS: 1487 consecutive patients admitted during 1990 and 1991 (one year before and one year after introduction of the system). INTERVENTION: Introduction of a computerised protocol management system on 1 January 1991. MAIN MEASURES: The number and cost of clinical chemistry tests requested per patient day. RESULTS: The total number of clinical chemistry tests requested per patient day by the unit declined 17% (p < 0.001, Student's t test) and of out of hours tests requested per patient day from 0.31 to 0.16, 48% (p < 0.001; Mann-Whitney U test), resulting in a 28% reduction (p < 0.001) in direct laboratory expenditure per patient-day. Overall, the number of tests per admission decreased by 24% (p < 0.001; Mann-Whitney U test). CONCLUSION: Use of the computerised protocol management system resulted in closer compliance with the protocols and a significant reduction in the overall level of requesting. IMPLICATIONS: Although similar systems need to be tested in other clinical settings, computerised protocol management systems may be important in providing appropriate and cost effective health care.

Clinical Laboratory Techniques↗
PubMed1994

Safety of alternating ganciclovir and foscarnet maintenance therapy in human immunodeficiency virus (HIV)-related cytomegalovirus infections. An open-labeled pilot study.

In the treatment of cytomegalovirus (CMV) disease in patients with AIDS, a life-long suppression therapy following an induction therapy consisting of ganciclovir or foscarnet is essential. Due to drug-related toxicities, anti-CMV therapy frequently has to be discontinued. To determine whether toxicities and side effects may be reduced with an alternating combination therapy consisting of ganciclovir and foscarnet (ganciclovir: 5 mg/kg every other day; foscarnet: 120 mg/kg every other day), 10 AIDS patients with CMV disease received this maintenance therapy for a median time of 18.5 weeks (5-51 weeks). Side effects were reported from 5 patients (nausea 5, malaise/fatigue 2, penile ulcers 1). Hematological or renal toxicities were mild, 1-week discontinuation of therapy due to neutropenia was necessary in 1 patient. Progression of CMV disease was observed in 3 patients at 2, 6, and 30 weeks of maintenance therapy. Median relapse-free interval for all patients was 105 days. We conclude that combination therapy with ganciclovir and foscarnet can be used safely for induction and maintenance therapy. Therefore, this regimen should be assessed in further trials to evaluate safety, efficacy, and the development of resistance in comparison to ganciclovir or foscarnet monotherapy.

AIDS-Related Opportunistic Infections↗
PubMed1994

[Human biomonitoring after a severe chemical accident--results of a study after the Hoechst AG chemical spill 22 February 1993].

A major industrial chemical accident occurred on 22 February 1993 at Hoechst AG Frankfurt/Germany. Approximately 11.8 tons of a chemical mixture (mostly chlorinated nitroarenes) were emitted, resulting in heavy contamination of Schwanheim, a nearby housing area. Urine samples were collected from the inhabitants of the affected area a few days after the accident and were analyzed for o-nitrophenol (ONP) as a representative metabolite to assess the actual uptake of the pollutants. As a result, ONP was found in urines of control subjects from elsewhere, an observation hitherto not described in the literature. Mean ONP excretion was about three times higher in the Schwanheim population than in the controls. The results show not only a higher accident-related but also a higher permanent ONP-excretion of the population of Schwanheim, pointing to a permanent environmental pollution in Schwanheim. Both results, the hitherto unknown ONP excretion in controls and regional differences in ONP excretion, require further investigation.

Accidents↗
PubMed1994

[Accident in the Hoechst AG company 22 February 1993. 2. Public health evaluation].

A major chemical accident occurred on 22 February 1993 at plant Griesheim of Hoechst AG Frankfurt/Germany during which approximately 11.8 tons of a chemical mixture containing mostly chlorinated nitroarenes were emitted leading to serious contaminations in Schwanheim/Goldheim, a nearby housing area. Numerous inhabitants of the contaminated area complained of irritation of eyes, skin and mucous membranes, headache and nausea, and 92 persons with moderate symptoms were reported to the National Health Department. Urine samples were collected from the inhabitants of the affected area a few days after the accident and analysed for o-nitrophenol as a representative metabolite to assess the actual uptake of pollutants. O-nitrophenol, however, was also detected in the urine of not knowingly exposed control subjects, an observation not hitherto described in literature. The median levels of o-nitrophenol were three times higher in the exposed population than in the controls. Taking into account the data on pollution measured in the environment, the reported intoxication symptoms, the results of biomonitoring, and the published literature on the components of the mixture, the following conclusions were drawn: (1) The exposure was not high enough to cause severe acute toxic effects. (2) Although the emitted mixture contained carcinogenic components according to animal experiments, the transient exposure to these chemicals does not increase the tumour risk to any measurable extent, i.e. demonstrable by epidemiological methods, especially if weighed against the permanent exposure to "normal" urban pollution.

Accidents, Occupational↗
PubMed1994

[Evaluation of inpatient psychotherapeutic-dermatologic treatment of neurodermatitis patients].

In a psychosomatic clinic an in-patient therapy-model for psychosomatic skin disorders was developed, conjoining psychoanalytic oriented psychotherapy with dermatologic standard therapy. The effects of this therapy are evaluated with standardized questionnaires in 40 patients with atopic dermatitis. Whereas changes concerning symptoms and depression occur in the course of the in-patient treatment, other personality changes cannot be found out before one-year follow-up questioning. All together the results of this study indicate that the combined treatment technique proves to be satisfactory.

Adult↗
PubMed1994

[The chemical accident of the Hoechst AG facility 22 February 1993--1. Extent of environmental pollution and clean-up].

A major industrial chemical accident occurred on 22 February 1993 at Hoechst AG Frankfurt/Germany. Due to a series of errors in operational procedures approximately 11.8 tons of a chemical mixture were emitted, partly resulting in heavy contamination of a nearby housing area. The chemical mixture consisted of about 26% anorganic and 74% organic substances, mostly chlorinated nitroarenes, the most important organic contaminant being o-nitroanisol (about 27% of the total amount). Maximum earth contamination in allotment gardens was up to 8 g o-nitroanisol/m2, in the housing area 547 mg/m2. Maximum air contamination was up to 18 micrograms o-nitroanisol/m3, declining quickly during redevelopment and staying constantly below 2 micrograms/m3 from 2 March 1993 onwards. In 96% of more than 300 indoor air measurements no o-nitroanisol could be detected. Redevelopment measurements were started and completed very quickly: Removal of contaminated earth, recultivation of the gardens, cutting bushes and cutting down coniferous trees, cutting off and renewing street-surfaces, cleaning up footpaths and roofs of the houses. Four weeks after the accident, redevelopment measurements were completed, as confirmed by numerous analyses.

Accidents↗
PubMed1994

Enhanced thrombin generation in children with sickle cell disease.

Recent studies suggest that increased activity of the coagulation system, measured with sensitive assays for activation markers, may be important in the pathogenesis of vascular occlusion in sickle cell disease (SCD). Since most of these studies were carried out in adult patients and SCD is an inherited disorder with severe morbidity even in childhood, we decided to determine the activity of the coagulation system in children with SCD. In a prospective study markers of thrombin generation as well as coagulation inhibitors were investigated in 16 homozygous SCD patients and 16 age-matched control children. Significantly increased plasma concentrations of the prothrombin fragment F1+2 and of thrombin-antithrombin III (TAT) complexes were found in SCD patients. The levels of protein C activity and total and free protein S were significantly reduced in SCD patients as compared with control values. Plasma AT III levels were not different in the two groups. We conclude that, in children with SCD, evidence of enhanced thrombin generation is present, which may in part be due to reduced levels of the inhibitors proteins C and S. The clinical relevance of this coagulation imbalance has to be demonstrated.

Adolescent↗
PubMed1994

Epidemiology of hepatocellular carcinoma. Evaluation of viral and other risk factors in a low-endemic area for hepatitis B and C.

To assess whether hepatocellular carcinoma (HCC) in patients with cirrhosis of the liver is associated with particular risk factors, a retrospective, case-control study was performed. Eighty-six patients with HCC (90% had underlying cirrhosis of the liver) were compared with 86 controls who had cirrhosis but not hepatocellular carcinoma. Hepatitis B surface antigen (HBsAg), antibodies to hepatitis B core antigen (anti-HBc), and to hepatitis C virus (anti-HCV) were evaluated; and alcohol and nicotine abuse were assessed by history. The prevalence of HBsAg and anti-HBc was similar in both, case and control patients. Antibodies to hepatitis C virus were detected more frequently among patients with HCC and cirrhosis (37%) compared to cirrhosis alone (22%). Alcohol abuse was found more frequently in patients with cirrhosis alone. Smoking habits were comparable between the two groups. None of the tested variables were related to an increased risk for HCC. Using an ordinary logistic regression approach, none of the variables could be identified as an independent risk factor for HCC. However, the combination of hepatitis B virus infection and hepatitis C virus infection was more prevalent in the patients with hepatocellular carcinoma and cirrhosis (48%) when compared to patients with cirrhosis alone (13%) (odds ratio 6.364; CI 1.149-35.229). In conclusion, we failed to identify independent risk factors for the development of HCC in Germany. However, the combination of hepatitis B and C virus infection increases the risk for liver cancer. Molecular analyses have to be performed to elucidate viral hepatocarcinogenesis.

Aged↗