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Biomedical subjects

M Peters

Publications and source records attributed to M Peters.

At least 145 records · Page 8Linked to original sources
PubMed2000

PCP in the blood plasma: current exposure of the population in Germany, based on data obtained in 1998.

The fungicidal substance pentachlorophenol (PCP) had been used commonly for wood protection and leather impregnation in Germany until 1989, when this substance was prohibited by law. Hence, the body burden in the general population in Germany has been steadily declining. The reference values (95th percentiles) in blood plasma decreased from 20 micrograms PCP/l in 1991 to 12 micrograms/l in 1996. In 1998 the current exposure in a large residential population was investigated. 623 persons with an average age of 34.6 years (0-62 years) were investigated. For all of them there was neither evidence of occupational contact with PCP nor of the presence of PCP in the residential indoor environment. The mean PCP concentration in the plasma samples was 2.4 +/- 3.9 micrograms/l, the median 1.7 micrograms/l, and the 95th percentile 6.1 micrograms/l, the maximum value was 59.3 micrograms/l. In children and adolescents higher median and 95th percentiles were obtained than in adults (median 2.5 vs. 1.5 micrograms/l and 95th percentile 7.7 vs. 5.9 micrograms/l). All values above 20 micrograms/l were checked again individually: relationships with the level of PCP in household dust could not be detected. In one family leather clothing containing PCP, however, was found to be the cause of unusually high PCP values in the blood. Our investigations confirm a trend observed in recent years: exposure to PCP in the population in Germany decreases steadily and leads to an actualized reference value of 6.1 micrograms PCP/l plasma. In individual cases, however, greatly increased PCP levels in blood can still occur today, for example due to leather clothing treated with PCP.

Adolescent↗
PubMed2000

Effects of myosin ATPase inhibitor 2,3-butanedione 2-monoxime on distributions of myosins, F-actin, microtubules, and cortical endoplasmic reticulum in maize root apices.

2,3-Butanedione 2-monoxime (BDM) is a general inhibitor of myosin ATPases of eukaryotic cells, and its effects on animal and yeast cells are well described. Using immunofluorescence and electron microscopy, we have analyzed the impacts of BDM on distributions of plant myosins, actin filaments (AFs), microtubules (MTs), and cortical endoplasmic reticulum (ER) elements in various cell types of maize root apices. Treatment of growing maize roots with BDM altered the typical distribution patterns of unconventional plant myosin VIII and of putative maize homologue(s) of myosin II. This pharmacological agent also induced a broad range of impacts on AFs and on cortical ER elements associated with plasmodesmata and pit fields. BDM-mediated effects on the actomyosin cytoskeleton were especially pronounced in cells of the root transition zone. Additionally, BDM elicited distinct reactions in the MT cytoskeleton; endoplasmic MTs vanished in all cells of the transition zone and cortical MTs assembled in increased amounts preferentially at plasmodesmata and pit-fields. Our data indicate that AFs and MTs interact together via BDM-sensitive plant myosins, which can be considered as putative integrators of the plant cytoskeleton. Morphometric analysis revealed that cell growth was prominently inhibited in the transition zone and the apical part, but not the central part, of the elongation region. Obviously, myosin-based contractility of the actin cytoskeleton is essential for the developmental progression of root cells through the transition zone.

Actins↗
PubMed2000

Liver regeneration induced by a designer human IL-6/sIL-6R fusion protein reverses severe hepatocellular injury.

The cytokine IL-6 plays a significant role in liver regeneration in conjunction with additional growth factors (HGF, TNF-alpha, and TGF-alpha). Many IL-6 effects depend on a naturally occurring soluble IL-6 receptor (sIL-6R). Here, the chimeric protein hyper-IL-6, constructed from the human IL-6 protein fused to a truncated form of its receptor, was found to have superagonistic IL-6 properties, and as such, enhanced liver cell regeneration. Hyper-IL-6 reversed the state of hepatotoxicity and enhanced the survival rates of rats suffering from fulminant hepatic failure after D-galactosamine administration. The hyper-IL-6 protein has a significant potential for use in the treatment of severe human liver diseases.

Animals↗
PubMed2000

Mycophenolate mofetil versus azathioprine in patients with chronic active ulcerative colitis: a 12-month pilot study.

OBJECTIVE: Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) of unknown etiology frequently requiring long-term therapy for control of symptoms and prevention of relapse. Azathioprine (AZA) has been shown to be effective and safe in the treatment of chronic active UC. However, the alternatives to treatment with AZA are limited. Our aim was to compare the efficacy and safety of treatment with mycophenolate mofetil (MMF)/prednisolone versus standard immunosuppressive treatment with azathioprine (AZA)/prednisolone in patients with chronic active UC. METHODS: The study was designed as an open comparison of MMF versus AZA. Twenty-four patients with active UC (Rachmilewitz score > or =6 points) were randomly assigned to the MMF (20 mg/kg)/prednisolone or AZA (2 mg/kg)/prednisolone group. The initial prednisolone dosage was 50 mg and was tapered according to a standard protocol. Treatment was scheduled for 1 yr. RESULTS: The rates of remission were higher in the AZA/prednisolone group (n = 12) than in the MMF/prednisolone group (n = 12) throughout the study. Remission rates were 92% versus 67% after 4 wk, 92% versus 67% after 3 months, 92% versus 67% after 6 months, 83% versus 78% after 9 months, and 100% versus 88% after 1 yr. The number of patients not requiring steroids was higher in the AZA/prednisolone group than in the MMF/prednisolone group. Moreover, in the AZA/prednisolone group no severe adverse events were recorded, whereas in the MMF/prednisolone group two severe adverse events were observed: one patient discontinued MMF after 6 months because of recurrent upper airway infections, and one patient exhibited a bacterial meningitis after 9 months. CONCLUSIONS: Treatment with AZA/prednisolone appears to be more effective and safe compared to MMF/prednisolone in patients with chronic active UC. MMF might be an alternative treatment for patients with contraindications to AZA. To further evaluate the effects of MMF in active UC, a placebo-controlled double-blinded study appears warranted.

Adult↗
PubMed2000

Superior vena cava thrombosis causing respiratory obstruction successfully resolved by stenting in a small bowel transplant candidate.

A 4 year old child was referred for small bowel transplantation. He had superior vena cava obstruction secondary to numerous central venous line placements; alternative routes for long term central venous access were compromised by extensive venous occlusive disease. Patency for the superior vena cava was re-established with stenting, which allowed for radiological placement of another central venous line. Long term survival in infants and young children with intestinal failure is dependent on adequate central venous access for the administration of parenteral nutrition. Line sepsis and physical damage to the catheter often necessitates multiple central venous catheter placements during their early life and these children are at risk of catheter related veno-occlusive disease. Recurrent sepsis and the loss of satisfactory venous access for the administration of parenteral nutrition is life threatening and is an indication for intestinal transplantation in up to 41% of patients reported by the small bowel registry.

Catheterization↗
PubMed2000

Refractory sprue syndrome with clonal intraepithelial lymphocytes evolving into overt enteropathy-type intestinal T-cell lymphoma.

INTRODUCTION: Recently, patients with refractory sprue have been shown to contain a clonal proliferation of phenotypically abnormal intraepithelial lymphocytes in their intestine. Whether this signifies early enteropathy-type intestinal T-cell lymphoma (EITCL) or a reactive condition is not clear. We report on a patient presenting with the findings of refractory sprue who subsequently developed overt EITCL. MATERIAL AND METHODS: Duodenal biopsies from 1997 (refractory sprue) and duodenal and jejunal biopsies from 1998 (intestinal T-cell lymphoma) were compared by immunohistochemistry and PCR for the detection of T-cell receptor (TCR)-gamma gene rearrangements. Clonal PCR products were sequenced. RESULTS: The duodenal biopsies from both 1997 and 1998 and the jejunal tumor biopsy showed villus atrophy and an increase of intraepithelial lymphocytes with an abnormal immunophenotype (CD3+, CD4-, CD8- and TCR-beta-). In all duodenal specimens including the one from 1997, and the jenunal tumor biopsy, an identical clonal amplificate was detected by enzymatic amplification of the TCR-gamma gene. CONCLUSION: These data suggest that refractory sprue containing a clonal proliferation of phenotypically abnormal intraepithelial lymphocytes may represent an early manifestation of EITCL. The detection of immunohistochemical negativity for several antigens normally found on intraepithelial lymphocytes such as CD8 or the TCR-beta chain in combination with clonal T-cell populations by PCR may be helpful in identifying refractory sprue with a malignant transformation.

CD3 Complex↗
PubMed2000

Mutations in the chloride channel gene, CLCNKB, leading to a mixed Bartter-Gitelman phenotype.

Gitelman syndrome is an inherited renal disorder characterized by impaired NaCl reabsorption in the distal convoluted tubule and secondary hypokalemic alkalosis. In clinical practice, it is distinguished from other hypokalemic tubulopathies by the presence of both hypomagnesemia and normocalcemic hypocalciuria. To date, only mutations in a single gene encoding the thiazide-sensitive NaCl cotransporter have been found as the molecular basis of GS. We describe three unrelated patients presenting with the typical laboratory findings of GS. Mutational analysis in these patients revealed no abnormality in the SLC12A3 gene. Instead, all patients were found to carry previously described mutations in the CLCNKB gene, which encodes the kidney-specific chloride channel ClC-Kb, raising the possibility of genetic heterogeneity. Review of the medical histories revealed manifestation of the disease within the first year of life in all cases. Clinical presentation included episodes of dehydration, weakness, and failure to thrive, much more suggestive of classic Bartter syndrome than of GS. The coexistence of hypomagnesemia and hypocalciuria was not present from the beginning. In the follow-up, however, a drop of both parameters below normal range was a consistent finding reflecting a transition from cBS to GS phenotype. The phenotypic overlap may indicate a physiologic cooperation of the apical thiazide-sensitive NaCl cotransporter and the basolateral chloride channel for salt reabsorption in the distal convoluted tubule.

Alkalosis↗
PubMed2000

On the presentation and interpretation of international homicide data.

Whitney in 1995 argued that White groups around the world have relatively low homicide rates compared to Black groups. He used the presumed similarity of homicide rates of White groups to argue for the importance of genetic factors and the unimportance of sociocultural factors in explaining group differences. We show that for Europeans, Whitney added two categories from United Nations data: homicide and death from a variety of other causes. For the U.S. White group, Whitney presented only homicide rates, thus making it appear as if Europeans have homicide rates comparable to those in the USA, when European rates are in fact considerably lower. The importance of careful scholarship in this area is emphasized.

Black or African American↗
PubMed2000

Does constructivist epistemology have a place in nurse education?

Nursing students who undertake the bachelor of nursing degree program are adults, many of whom are considered mature students. As such, they have significant life experiences and a vast amount of knowledge that has been acquired both formally and informally. Much of formal education historically, and even today, is content and curriculum driven, and teacher focused. Constructivist epistemology offers an alternative to traditional pedagogy in that it is student focused and considers previous learning done by the students as a foundation upon which to modify, build, and expand new knowledge. Constructivism also appears to be congruent with adult education theory and therefore offers great potential for the enhancement of self-directed learning. It enhances empowered learning because of the consideration of prior knowledge and the ownership of learning by the students. Implicit in this is the development of metacognitive skills that are an important facet of active and self-directed learning. As a result of undergraduate learning within a constructivist framework, there are likely to be benefits for nurses in the practice setting for making the transition from inexperienced to experienced practitioners. Constructivist learning frameworks provide learning skills that enhance knowledge acquisition with understanding.

Adult↗
PubMed2000

Negative pressure ventilation via chest cuirass to decrease ventilator-associated complications in infants with acute respiratory failure: a case series.

Pulmonary and nonpulmonary complications of invasive positive pressure ventilation are well documented in the medical literature. Many of these complications may be minimized by the use of noninvasive ventilation. During various periods of medical history, negative pressure ventilation, a form of noninvasive ventilation, has been used successfully. We report the use of negative pressure ventilation with a chest cuirass to avoid or decrease the complications of invasive positive pressure ventilation in three critically ill infants at two institutions. In each of these cases, chest cuirass ventilation improved the patient's clinical condition and decreased the requirement for more invasive therapy. These cases illustrate the need for further clinical evaluation of the use of negative pressure ventilation utilizing a chest cuirass.

Acute Disease↗
PubMed2000

Case studies of the hepatitis B patient: a panel discussion.

In recent years, there have been significant advances in the treatment of patients with hepatitis B who are candidates for liver transplantation. This includes the prevention and management of hepatitis B posttransplantation. However, there is no established protocol for treating these patients. Ultimately, the goal would be to have patients HBV-DNA negative pretransplantation and then to prevent HBV recurrence posttransplantation to help ensure their quality of life. Several clinical case scenarios are presented and possible treatment solutions have been suggested. The timing of a transplant is critical due to the risk of viral mutation while the patient is on a nucleoside analogue antiviral agent and waiting for an organ. One successful option might be to start therapy pretransplant and continue it posttransplant. Combination therapy appears to provide the most effective course of treatment. This should include a nucleoside analogue and patients should be covered with hepatitis B immune globulin throughout the course of therapy. Several other variations of combination therapy are discussed, but many clinical issues remain to be resolved. Guidelines for future studies designed to answer these questions are proposed.

Adult↗
PubMed1999

[Quality of life in children with sickle cell disease in Amsterdam area].

OBJECTIVE: To determine the differences in quality of life between children with sickle cell disease and healthy immigrant children. DESIGN: Descriptive, comparative. METHOD: The quality of life of children with sickle cell disease between 5 and 15 years old being treated in the Emma Children's Hospital AMC in Amsterdam, the Netherlands, was assessed by using a questionnaire for parents (TNO-AZL Children's Quality of Life Questionnaire (TACQOL) parent form) if the child was between 5 and 11 years old and a questionnaire for children (TACQOL child form) if the child was between 8 and 15 years old. The study period was April-October 1998. The questionnaires were completed by 45 (parents of) patients. The results were compared with a healthy reference group of immigrant children. Statistical analysis was performed using the Student t-Test. RESULTS: Children with sickle cell disease as well as their parents scored significantly lower on the items general physical, motor and independent daily functioning and on occurrence of negative emotions. No significance was observed for the items cognitive functioning and school performance nor for social functioning or occurrence of positive emotions. CONCLUSION: In children, sickle cell disease leads to compromised physical and possibly also psychological wellbeing, as well as the experience of decreased independence in daily functioning, but not to compromised cognitive or social aspects of the quality of life.

Adolescent↗