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Biomedical subjects

E Harms

Publications and source records attributed to E Harms.

At least 55 records · Page 3Linked to original sources
PubMed2000

Completion of meiosis in Drosophila oocytes requires transcriptional control by grauzone, a new zinc finger protein.

Mutations in grauzone or cortex cause abnormal arrest in Drosophila female meiosis. We cloned grauzone and identified it as a C2H2-type zinc finger transcription factor. The grauzone transcript is present in ovaries and at later developmental stages. A Grauzone-GFP fusion protein is functional and localizes to nuclei of both nurse cells and follicle cells during oogenesis. Three lines of evidence indicate that grauzone and cortex interact: reducing cortex function enhanced the grauzone mutant phenotype; cortex transcript abundance is reduced in the absence of grauzone function and Grauzone protein binds to the cortex promoter. These results demonstrate that activation of cortex transcription by grauzone is necessary for the completion of meiosis in Drosophila oocytes, and establish a new pathway that specifically regulates the female meiotic cell cycle.

Alleles↗
PubMed1999

Correction of leukocyte adhesion deficiency type II with oral fucose.

We describe a simple, noninvasive, and effective therapy for leukocyte adhesion deficiency type II (LAD II), a rare inherited disorder of fucose metabolism. This disorder leads to an immunodeficiency caused by the absence of carbohydrate-based selectin ligands on the surface of neutrophils as well as to severe psychomotor and mental retardation. The fucosylation defect in LAD II fibroblasts can be corrected by addition of L-fucose to the culture medium. This prompted us to initiate dietary fucose therapy on a patient with LAD II. Oral supplementation of fucose in this patient induced the expression of fucosylated selectin ligands on neutrophils and core fucosylation of serum glycoproteins. During 9 months of treatment, infections and fever disappeared, elevated neutrophil counts returned to normal, and psychomotor capabilities improved.

Administration, Oral↗
PubMed1999

Decreased availability of GDP-L-fucose in a patient with LAD II with normal GDP-D-mannose dehydratase and FX protein activities.

Leukocyte adhesion deficiency type II (LAD II) is caused by a disorder in the metabolism of GDP-L-fucose, which causes hypofucosylation of glycoconjugates. This study analyzes a newly identified LAD II patient who shows the same severe hypofucosylation of glycoconjugates as the other described patients. However, in vitro assays of cytosolic extracts from leukocytes and fibroblasts of the patient demonstrated a normal GDP-L-fucose biosynthesis from GDP-D-mannose. Analysis of the two enzymes involved in the pathway, GDP-D-mannose 4,6-dehydratase and FX protein, revealed normal numbers of transcripts without any detectable mutations within the coding regions of either gene. In contrast to previously published observations [Sturla et al. (1998) FEBS Lett. 429, 274-278], the major pathway of GDP-L-fucose synthesis can be normal in LAD II.

Carbohydrate Epimerases↗
PubMed1999

Coagulation-associated complications of indwelling arterial and central venous catheters during heparin prophylaxis--a prospective study.

UNLABELLED: A prospective observational study was carried out to investigate complications of arterial and venous indwelling catheters. All patients of a mixed NICU/PICU admitted during a 12-month period were enrolled in this study with a stringent protocol of catheter prophylaxis, using heparin via continuous infusion in a dose of 100 IU/kg/day body weight or at least 100 IU/kg/day for each arterial and/or central venous catheter. Patients were regularly monitored for edema, thrombus, ischemia and catheter obstruction, i.e. complications amenable to heparinization. A total of 292 catheters in 130 patients were recorded. Patients' weight ranged between approximately 600 g to 10,000 g. Depending on the insertion site or type of catheter the frequency of complications was as follows: edema 0-12%; catheter obstruction 7-24%; ischemia 28-40%. No case of persistent thrombosis was detected. CONCLUSION: A stringent protocol of heparinization leads to a low incidence of complications potentially amenable to anticoagulation.

Anticoagulants↗
PubMed1999

Leukocyte adhesion deficiency II syndrome, a generalized defect in fucose metabolism.

Leukocyte adhesion deficiency II has been described in only 2 patients; herein we report extensive investigation of another patient. The physical stigmata were detected during prenatal ultrasonographic investigation. Sialyl-Lewis X (sLex) was absent from the surface of polymorphonuclear neutrophils, and cell binding to E- and P-selectin was severely impaired, causing an immunodeficiency. The elevation of peripheral neutrophil counts occurred within several days after birth. A severe hypofucosylation of glycoconjugates bearing fucose in different glycosidic links was present in all cell types investigated, demonstrating that leukocyte adhesion deficiency II is not only a disorder of leukocytes but a generalized inherited metabolic disease affecting the metabolism of fucose.

C-Reactive Protein↗
PubMed1999

Incidentally discovered pituitary lesions: high frequency of macroadenomas and hormone-secreting adenomas - results of a prospective study.

OBJECTIVE: With increasing use of computed tomography and magnetic resonance imaging, pituitary adenomas are being discovered incidentally with increasing frequency. However, limited data are available concerning the clinical importance and natural history of such 'incicentalomas'. We have undertaken a prospective study to investigate changes in adenoma size and endocrine and visual function in patients with incidentally discovered intrasellar masses. PATIENTS AND METHODS: Our study included 67 patients with incidentalomas of the pituitary gland during a 5-year period (1992-96). 50 of these patients were followed up prospectively over a mean period of 2.7 years. Initially, all patients underwent endocrine testing and ophthalmological examinations as well as magnetic resonance imaging or computed tomography scans. These investigations were repeated after 3 months and then annually. RESULTS: 42 (62.7%) out of 67 patients with incidentalomas had microadenomas whereas 37.3% had macroadenomas. Macroadenomas were found more frequently in men (52.2%). Visual field defects could be documented in 4.5% of the patients. Partial deficiency of anterior pituitary function was present in 14.9%. Eight patients (11.9%) had prolactinomas. An increase in adenoma size was detected in 3.2% of the microadenomas and in 26.3% of the macroadenomas within the follow-up period. CONCLUSION: Macroadenomas and hormone secreting adenomas are not uncommon in patients with pituitary incidentalomas. Macroadenomas should be closely monitored for tumour enlargement. All patients should undergo biochemical assessment and ophthalmological examination, since endocrine dysfunction or visual field defects may be present at the time a pituitary incidentaloma is detected.

Adenoma↗
PubMed1998

Carbohydrate-deficient glycoprotein syndrome type Ib. Phosphomannose isomerase deficiency and mannose therapy.

Phosphomannose isomerase (PMI) deficiency is the cause of a new type of carbohydrate-deficient glycoprotein syndrome (CDGS). The disorder is caused by mutations in the PMI1 gene. The clinical phenotype is characterized by protein-losing enteropathy, while neurological manifestations prevailing in other types of CDGS are absent. Using standard diagnostic procedures, the disorder is indistinguishable from CDGS type Ia (phosphomannomutase deficiency). Daily oral mannose administration is a successful therapy for this new type of CDG syndrome classified as CDGS type Ib.

Cells, Cultured↗
PubMed1998

The redox status of aminothiols as a clue to homocysteine-induced vascular damage?

Vascular disease associated with increased blood concentrations of homocysteine has been known for many years. However, the pathobiochemical mechanisms leading to vasculopathy are still unknown. Several attempts have been made to establish in vitro model systems for the evaluation of homocysteine specific effects in cultured cells. It was concluded from these experiments, that hyperhomocysteinemia has to be considered as a risk factor for atherosclerosis exerting its effects mainly by mechanisms involving oxidative damage. Here, we summarize the homocysteine induced cellular effects which may be due to alterations of the redox thiol status. Effects specific for homocysteine are demonstrated working on different levels of cellular processes involving protein folding and regulation of nuclear factor kappaB (NF-kappaB) controlled gene transcription, the latter opening a new perspective for a novel pathway by which homocysteine might enhance chronic inflammation of the endothelium and possibly contributes to the development of atherosclerosis.

Arteriosclerosis↗
PubMed1998

Persistent infection with small colony variant strains of Staphylococcus aureus in patients with cystic fibrosis.

In a 34-month prospective study to determine the prevalence of Staphylococcus aureus small colony variants (SCVs) in cystic fibrosis (CF) patients, S. aureus SCVs or SCVs plus normal S. aureus were recovered from 26 of 78 patients; 27 patients harbored only normal S. aureus. By pulsed-field gel electrophoresis, clonal identity was demonstrated of SCV and normal strains isolated at the same time and of multiple S. aureus SCV and normal strains in consecutive specimens from individual patients. All S. aureus SCVs were resistant to antifolate antibiotics, while the corresponding parent strains were susceptible, and in 11 of 12 SCV/normal pairs, gentamicin was less active against S. aureus with the SCV phenotype than against the normal isolate. Analysis of the underlying auxotrophism of SCVs revealed hemin, thymidine, and/or menadione dependencies. Thus, S. aureus SCVs are highly prevalent in respiratory secretions of CF patients, persist over extended periods, and may contribute to S. aureus persistence in CF patients.

Adolescent↗
PubMed1998

Mapping of Drosophila mutations using site-specific male recombination.

Although recombination does not usually occur in the male Drosophila germline, site-specific recombination can be induced at the ends of P elements. This finding suggested that male recombination could be used to map Drosophila mutations. In this article, we describe the general method and its application to the mapping of two EMS-induced female-sterile mutations, grauzone and cortex. Within two months, the grauzone gene was mapped relative to seven different P-element insertion sites, and cortex was mapped relative to 23 different P-elements. The results allowed us to map grauzone to a region of about 50 kb, and cortex distal to the chromosomal region 33E. These experiments demonstrate that P-element-induced site-specific male recombination is an efficient and general method to map Drosophila autosomal mutations.

Animals↗
PubMed1998

False-positive gliadin and endomysium antibodies and exocrine pancreatic insufficiency as pitfalls in the differential diagnosis of duodenal Crohn's versus celiac disease.

We report a 13-yr-old boy with Crohn's disease in the upper gastrointestinal tract presenting with abdominal pain, failure to thrive, recurrent fever, iron-deficient anemia, and exocrine pancreatic insufficiency. Initially, latent celiac disease was suggested because of normal endoscopic findings, the finding of non-specific inflammation on histological evaluation of duodenal biopsies, positive IgA and IgG gliadin, as well as endomysium antibodies and exocrine pancreatic insufficiency. There was no response to a gluten-free diet. A reevaluation revealed Crohn's disease.

Abdominal Pain↗
PubMed1997

Use of 1H NMR spectroscopy and computer simulations To analyze histidine pKa changes in a protein tyrosine phosphatase: experimental and theoretical determination of electrostatic properties in a small protein.

In bovine low Mr protein tyrosine phosphatase, the pKa values of His-66 and His-72 are 8.3 and 9.2, respectively. These unusually high values were hypothesized to be caused by electrostatic interactions with several nearby negatively charged groups. To test this, mutant enzymes were made in which one or more carboxylate side chains were removed or introduced near the histidines. Michaelis kinetic parameters, measured using p-nitrophenyl phosphate as a substrate, indicated that all mutant enzymes retained approximately 50% or more of the activity of wild-type enzyme. The effect that each mutation had on the pKa of the nearby histidine was monitored by 1H NMR spectroscopy using the MLEV-17 pulse sequence to filter out the broad interfering amide resonances in the spectra. Independently, computer simulations of the pKas were obtained using the finite difference method to solve the linear Poisson-Boltzmann equation. The proximity of a charged residue to the titrating histidine imidazole largely determined the extent of the pKa perturbation. The change in pKa for His-72 in the mutant enzymes was -1.69 units for D42A, -2.36 units for E23A, -2.99 units for E23A/D42A, and unchanged for E139A and Q143E. Thus, the pKa of His-72 in the double mutant E23A/D42A decreased to nearly that of a free histidine imidazole group. The His-66 pKa change was -1.25 units for E139A and was not significant for the other mutants. His-66, Glu-139, and Gln-143 are at the protein surface and much more exposed to the higher solvent dielectric compared to His-72, Glu-23, and Asp-42. These structural characteristics explain the smaller decrease in the observed pKa of His-66 for the E139A mutant compared to the decrease in the pKa of His-72 when a single nearby carboxylate was removed. These observations were adequately predicted by theoretical electrostatic calculations using the Poisson-Boltzmann equation as a model for a solute molecule of low dielectric in solution of high dielectric.

Animals↗
PubMed1997

Ultrastructural localization of IgG and TPO in autoimmune thyrocytes referring to the transcytosis of IgG and the antigen presentation of TPO.

While autoantibodies against thyroid peroxidase (TPO) are known to produce cytotoxicity in vitro, their in vivo effects are still obscure. In addition, the mechanism of TPO autoantibody creation needs to be disclosed because the localization of TPO on thyrocytes is considered to be restricted to the apical membrane, which is not in contact with immunocompetent cells. In order to study these crucial processes in the pathogenesis of thyroid autoimmunity, the ultrastructural localization of TPO and IgG was determined and quantified in thyrocytes of normal thyroid gland and thyroid tissue of patients suffering from Graves' disease. This was done by using ultrathin frozen sections and the immunogold method. IgGs were detected in the follicular lumen, close to the apical membrane, in transport vesicles, the endoplasmic reticulum, and the Golgi apparatus of thyrocytes from patients with Graves' disease. The labeling of TPO in the basolateral membrane was distinctly lower than that of the apical membrane, but was significant in comparison to the plasma membrane labeling of fibroblasts present in the same sections. These data indicate that thyroid autoantibodies may perform their cytotoxic function in intracellular compartments besides the plasma membrane. TPO molecules on the basolateral membrane of HLA class II antigen-positive thyrocytes may initiate antigen presentation of TPO as well as the formation and uptake of TPO autoantibodies.

Autoantigens↗
PubMed1997

Intellectual, neurologic, and neuropsychologic outcome in untreated subjects with nonphenylketonuria hyperphenylalaninemia. German Collaborative Study on Phenylketonuria.

Based on the serum phenylalanine levels under free diet patients with hyperphenylalaninemia are classified as "classical" (>1200 micromol/L), "mild" (600-1200 micromol/L), or "non-phenylketonuria (PKU)-hyperphenylalaninemia" (<600 micromol/L). Recent studies revealed intellectual, neurologic, and neuropsychologic deficits as well as abnormalities of cerebral white matter (magnetic resonance imaging, MRI) in patients with early and adequately treated PKU. In addition deficits in IQ were reported for a group of 4-y-old patients with untreated mild PKU and non-PKU hyperphenylalaninemia (serum phenylalanine levels below 900 micromol/L). As a consequence, a lifelong diet with serum phenylalanine levels below 400 micromol/L was recommended even for those patients with serum phenylalanine levels remaining consistently between 400 and 600 micromol/L. Generally patients with non-PKU hyperphenylalaninemia were not treated, as a normal outcome was suspected, but the clinical development of patients with non-PKU hyperphenylalaninemia was not so far studied systematically. We assessed 28 untreated patients with non-PKU hyperphenylalaninemia (age: mean = 21.8, SD = 4.2 y) for IQ, school and job career, clinical-neurologic development, fine motor performances, selective and sustained attention, as well as for frontal lobe-dependent "executive functions." In addition, cranial MRI was obtained in 10 of these patients. Compared with healthy control subjects, matched for age, sex, and socioeconomic status, the patients reached normal results in all clinical and psychometric tests. Cranial MRI revealed no abnormalities. Additionally, no significant correlations between serum phenylalanine levels and test results were obtained. In the absence of any demonstrative effect, treatment is unlikely to be of significant effect in patients with non-PKU hyperphenylalaninemia.

Adolescent↗
PubMed1997

[Development of leadership in a nursing college].

This study is conducted within the context of nursing colleges and focuses on the empowerment of educational staff in a nursing college to facilitate excellence in leadership practice. A qualitative exploratory and descriptive study was conducted in different phases: the views and expectations of educational staff as leaders, as well as the views and expectations of the fourth year students as followers and potential professional leaders were explored and described by means of focus group interviews. A provisional conceptual framework for leadership development in a nursing college was compiled, exposed to a literature control and a final conceptual framework was refined, together with guidelines for leadership development in a nursing college. This article focuses on the final conceptual framework as well as the programme for leadership development in a nursing college. It is recommended that this programme be implemented and exposed to purposeful evaluation.

Curriculum↗