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Biomedical subjects

P Meyer

Publications and source records attributed to P Meyer.

At least 127 records · Page 7Linked to original sources
PubMed1999

[Dermatitis and conjunctivitis after contact with Euphorbia myrsinites (wolf's milk extract)--a case report].

BACKGROUND: Fresh sap of euphorbiaceae leads to a toxic burn of the skin and the eyes. Since years the sap of euphorbiaceae has been used in the treatment of different kinds of verrucas. PATIENTS: After contact with the sap of Euphorbia myrsinites three children developed a toxic dermatitis. In addition, the youngest girl showed a conjunctivitis and an occlusion of the right eye. Phorbolesters are considered to be responsible for the toxicity of the euphorbiaceae. All three children have resulted in a restitutio ad integrum. CONCLUSION: This case report is demonstrating the danger of toxic burn of this kind of plant.

Administration, Topical↗
PubMed1999

Localization of nitric oxide synthase isoforms in porcine ocular tissues.

PURPOSE: To determine by immunohistochemistry the distribution of different nitric oxide synthases (NOS) isoforms in the porcine eye. METHODS: By light microscopy (immunofluorescence), porcine ocular tissues were investigated using monoclonal antibodies against neuronal NOS (nNOS; NOS I), endothelial NOS (ecNOS; NOS III), and macrophage NOS (macNOS; NOS II). RESULTS: Specific nNOS immunoreactivity was detected along the apical cytoplasmic portions of the non-pigmented and pigmented ciliary epithelial cells, in the endothelial lining of the corneoscleral meshwork and the uveal cords of the iridocorneal angle tissue, as well as in the photoreceptor layer of the sensory retina. Immunoreactivity for ecNOS was confined to the vascular endothelium of the vessels of the conjunctiva, iris, ciliary body, retina, choroid and optic nerve. A mild immunostaining for macNOS was present in the cytoplasm of some non-pigmented ciliary epithelial cells. CONCLUSIONS: The predominant localization of nNOS in ciliary epithelial and trabecular endothelial cells suggests a possible involvement of nNOS in both the production and outflow of aqueous humor in porcine eyes.

Animals↗
PubMed1999

Effect of zidovudine postexposure prophylaxis on the development of HIV-specific cytotoxic T-lymphocyte responses in HIV-exposed healthcare workers.

We evaluated the effects of zidovudine postexposure prophylaxis (PEP) on the development of human immunodeficiency virus (HIV) envelope-specific cytotoxic T-lymphocyte responses in 20 healthcare workers with occupational exposures to HIV. Seven healthcare workers were treated with zidovudine PEP. Only 1 of 7 treated, versus 6 of 13 not treated, developed an HIV envelope-specific cytotoxic T-lymphocyte response. These data suggest that zidovudine abrogated HIV-specific cytotoxic T-lymphocyte responses. HIV-specific cytotoxic T-lymphocyte responses may be useful as a surrogate marker of HIV replication in the evaluation of new regimens for PEP of occupational HIV exposures.

Anti-HIV Agents↗
PubMed1999

The severity of histopathological changes of leukocytoclastic vasculitis is not predictive of extracutaneous involvement.

Leukocytoclastic vasculitis is defined by histologic features and can be observed in a wide range of entities. Independent of the causative disease, extracutaneous complications are frequent, mainly in the kidneys and gastrointestinal tract. It has been suggested that the severity of histological changes could correlate with the clinical course of the disease. We have therefore compared the severity of histological changes of leukocytoclastic vasculitis to clinical and laboratory findings indicative of extracutaneous involvement in a large group of patients. Among 289 patients followed for cutaneous vasculitis, we included 184 patients with purpuric papules and proven leukocytoclastic vasculitis who all had standardized investigations. A cutaneous biopsy was performed early and standardized laboratory investigations were carried out. The slides were retrospectively randomized and the depth of vasculitis and severity of vascular necrosis were determined according to a semiquantitative scale. These data were compared to the renal, gastrointestinal and articular symptoms using Fischer's exact test, Chi-square test and variance analysis. The intensity of vascular necrosis and the depth of vasculitis were no more severe in patients having renal changes, gastrointestinal involvement or articular symptoms. Both variance analysis and Chi-square tests failed to show a significant increase in the severity score in patients having extracutaneous complications. In this study, the severity of histopathological changes was not predictive of extracutaneous involvement. Thus it appears that the degree of involvement of the cutaneous vessels probably does not correlate with that of vessels in visceral organs.

Adolescent↗
PubMed1999

Kinetic modeling of N-[11C]methylpiperidin-4-yl propionate: alternatives for analysis of an irreversible positron emission tomography trace for measurement of acetylcholinesterase activity in human brain.

N-[11C]Methylpiperidin-4-yl propionate ([11C]PMP) is a substrate for hydrolysis by acetylcholinesterase (AChE). This work evaluates kinetic analysis alternatives for estimation of relative AChE activity using dynamic positron emission tomography (PET) studies of [11C]PMP. The PET studies were performed on three groups of subjects: (1) 12 normal volunteer subjects, aged 20 to 45 years, who received a single intravenous injection of 16 to 32 mCi of [11C]PMP; (2) six subjects, aged 21 to 44 years, who received two 16-mCi injections of [11C]PMP (baseline and visual stimulation, respectively); and (3) five subjects, aged 24 to 40 years, who received two 16-mCi injections separated by 200 minutes (baseline and after a 1-hour constant infusion of 1.5 mg of physostigmine, respectively). Dynamic acquisition consisted of a 17-frame sequence over 80 minutes. All analysis methods were based on a first-order kinetic model consisting of two tissue compartments with the parameter k3, representing PMP hydrolysis, being the index of AChE activity. Four different schemes were used to estimate k3: (1) an unconstrained non-linear least-squares fit estimating blood-brain barrier transport parameters, K1 and k2, in addition to the hydrolysis rate constant k3; (2) and (3), two methods of constraining the fit by fixing the volume of distribution of free tracer (DVfree); and (4), a direct estimation of k3 without use of an arterial input function based on the shape of the tissue time-activity curve alone. Results showed that k3 values from the unconstrained fitting and no input methods were estimated with similar accuracy, whereas the two methods using DVfree constraints yielded similar results. The authors conclude that the optimal analysis method for [11C]PMP differs as a function of AChE activity. All four methods gave precise measures of k3 in regions with low AChE activity (approximately 10% coefficient of variation in cortex), but surprisingly, with unconstrained methods yielding estimates with lower variability than constrained methods. In regions with moderate to high AChE activity, constrained methods were required to yield meaningful estimates and were superior to the unconstrained methods.

Acetylcholinesterase↗
PubMed1999

Transgenic tobacco plants expressing the Drosophila Polycomb (Pc) chromodomain show developmental alterations: possible role of Pc chromodomain proteins in chromatin-mediated gene regulation in plants.

The chromodomain of the Drosophila Polycomb (Pc) protein has been introduced into tobacco nuclei to determine its location in the nucleus and its effect on plant development. Pc is a repressor of homeotic Drosophila genes that shares a well-conserved, although not identical, chromodomain with a structural heterochromatin component, Heterochromatin Protein 1. The chromodomains might therefore play a common role in chromatin repression. An analysis of transgenic plants expressing the Pc chromodomain, which was linked to the green fluorescent protein, suggested that the Pc chromodomain has distinct target regions in the plant genome. Transgenic plants expressing the Pc chromodomain had phenotypic abnormalities in their leaves and flowers, indicating a disruption in development. In axillary shoot buds of plants displaying altered leaf phenotypes, enhanced expression of a homeodomain gene, which is downregulated in wild-type leaves, was found. In Drosophila, Pc has been shown to possess distinct chromosome binding activity and to be involved in the regulation of development-specific genes. Our results support the assumptions that the heterologous chromodomain affects related functions in Drosophila and in plants, and that chromatin modification mechanisms are involved in the regulation of certain plant genes, in a manner similar to chromatin-mediated gene regulation in Drosophila.

Base Sequence↗
PubMed1999

Microangiopathy of the brain and retina with hearing loss in a 50 year old woman: extending the spectrum of Susac's syndrome.

A 50 year old woman presented with a subacute onset of vertigo and diplopia followed by an encephalopathy with confusion, spasticity, ataxia, myoclonus, and multiple branch retinal arteriolar occlusions and unilateral sensorineural deafness. Brain biopsy confirmed multiple microinfarcts with no vasculitis. After the procedure she had a right iliofemoral deep vein thrombosis and was found to be heterozygous for the factor V Leiden mutation. She was treated with anticoagulants and made a marked recovery with no relapses 6 months after presentation. This case extends the age range at which Susac's syndrome can present, and raises the possibility that the condition may be associated with abnormalities of coagulation.

Brain↗
PubMed1999

Alpha2-macroglobulin and eosinophil cationic protein in the allergic airway mucosa in seasonal allergic rhinitis.

As previously demonstrated in seasonal allergic rhinitis, increased microvascular permeability and eosinophil activation are key features of allergic airway inflammation. In the present study, the hypothesis that exudation of alpha2-macroglobulin may cause the appearance of eosinophil cationic protein (ECP) in the airway lumen was explored. Nasal lavages were carried out using the nasal pool device before and during the pollen season both at baseline and after histamine challenge in 10 children with allergic rhinitis. Nasal lavage fluid levels of alpha2-macroglobulin and ECP were determined. All patients experienced nasal symptoms of allergic rhinitis during the pollen season (p<0.01-0.05). Baseline nasal lavage fluid levels of alpha2-macroglobulin and ECP were increased during the season (p<0.01-0.05) and were found to be well correlated (p<0.0001). Histamine produced concentration-dependent plasma exudation before and during the pollen season, but it was only during the pollen season that this caused an increase in the lavage fluid levels of ECP (p<0.05). These data suggest that exudation of plasma and increased tissue levels and output of eosinophil cationic protein characterize nasal mucosal inflammation in children with seasonal allergic rhinitis. The plasma exudation process in part may account for lumenal entry of eosinophil cationic protein molecules that have been released in mucosal tissue compartments. A combination of induced exudation and nasal lavage may improve the yield of important markers of inflammation in studies of nasal diseases.

Biomarkers↗
PubMed1999

Fibrinolytic activity in peripheral atherosclerosis in the elderly.

Increased concentrations of plasminogen activator inhibitor type 1 (PAI-1) and of D-dimer have jointly been found in subjects with cardiovascular disease. To understand this apparent paradox of increased inhibition of fibrinolysis (high PAI-1) combined with increased fibrinolytic activity (high D-dimer), we examined the relation between D-dimer, PAI-1 and the activator of fibrinolysis, tissue type plasminogen activator (t-PA) in subjects with varying severity of peripheral atherosclerosis. In 325 subjects selected from the Rotterdam Study, a cohort of 7983 men and women aged 55 years and over, the ankle to brachial systolic blood pressure ratio, t-PA antigen and activity, PAI-1 antigen and D-dimer were measured. T-PA antigen and t-PA activity were, independent from each other, increased with degree of atherosclerosis; t-PA antigen increased with 3.5 ng/ml (SE 1.7, p = 0.04) and t-PA activity with 0.46 IU/ml (0.20, p = 0.02) per unit decrease in ankle to brachial pressure ratio (i.e. increase in atherosclerosis). PAI-1 antigen was not related to atherosclerosis. More marked atherosclerosis was associated with increased D-dimer, mainly in subgroups with PAI-1 antigen below 50 ng/ml, t-PA antigen below 10 ng/ml, or t-PA activity above 1.5 IU/ml. In contrast to current beliefs, we found that only a fraction of the variation of t-PA antigen was due to the variation in circulating PAI-1 antigen. A slight positive association was observed between t-PA antigen and D-dimer. PAI-1 and t-PA activity were not associated with D-dimer concentration. In conclusion, in subjects with peripheral atherosclerosis PAI-1 antigen is not increased, but low PAI-1 levels (and possibly also low levels of t-PA antigen and high levels of t-PA activity) appear to be required to increase circulating D-dimer. This suggests that increased D-dimer levels in subjects with atherosclerosis do not reflect increased inhibition, but rather reflect increased fibrinolysis.

Aged↗
PubMed1999

Somatostatin receptor scintigraphy of a patient with a giant invasive prolactinoma.

A 41-year-old with a giant prolactinoma underwent in-111 pentetreotide (Octreotide) imaging showing very intense tracer uptake in the region of the anterior skull base. In contrast, there was no significant response to Octreotide therapy. Prediction of clinical responsiveness to Octreotide therapy in patients with pituitary adenomas may depend on the presence of somatostatin receptor subtype 5. Pentetreotide does not avidly bind to this receptor subtype and therefore, cannot be used clinically to predict therapeutic Octreotide responsiveness in patients with large prolactinomas.

Adult↗
PubMed1999

From "uncertifiable" medical practice to Berlin Clinic of Women Doctors: the medical career of Franziska Tiburtius (M.D. Zurich, 1876).

Problems in gender expectations and relationships complicated increasing professionalization of medical arts at an important point of transformation toward the modern industrial European state. Subordination of women's work in these processes altered possible outcomes for German society in general and for female medical careers in particular. Franziska Tiburtius was one of twenty German women who graduated from the coeducational medical school in Zurich, Switzerland, in the nineteenth century. She was a founder of the Clinic of Women Doctors despite prohibitions against certifying women as physicians. Imperial Germany was the last Western nation to admit women to full medical practice in 1899.

Germany↗
PubMed1998

Six French sheathless coronary angioplasty using a novel technique to introduce the guiding catheter: the INTRUC, a preliminary retrospective study.

This registry describes our preliminary experience with a novel introducing-catheter allowing direct percutaneous introduction of the 6F guiding catheter (G-C), minimizing the puncture size, preventing vessel scraping, and improving the pushability and torque response of the G-C. In 1995, 203 patients had sheathless PTCA, using this device. Eighty-five percent were male. Mean age was 65+/-10 years. Thirty-nine percent had stable angina, 35% unstable angina, 7% evolving infarction, and 19% recent infarction. Two hundred fifty-six lesions were treated (1.26/patient). One hundred eight patients (52%) received one (85%) or more than one (15%) stent. The procedural success rate was 98%. Mean coronary stenosis was 82+/-10% and decreased to 20+/-15% after PTCA. No major complication occurred. The guiding catheter was immediately removed in 95% of patients, despite heparinization. No patient required surgery or blood transfusion for vascular complications, and only 7 had minor local complications (3.5%). Sheathless angioplasty provides no technical difficulties and has the same safety and quality as conventional angioplasty using a sheath. Immediate removal of the guiding catheter, without keeping vascular access, has no deleterious effect, allows early mobilization, and may limit the risk of vascular complications.

Adult↗
PubMed1998

Meropenem monotherapy versus combination therapy with ceftazidime and amikacin for empirical treatment of febrile neutropenic patients.

Infections remain the major cause of morbidity and mortality among neutropenic cancer patients. The current study addresses the question whether monotherapy with the new broad-spectrum carbapenem meropenem exhibits efficacy comparable to that of the standard combination therapy with ceftazidime and amikacin for empirical treatment of febrile neutropenic patients. Seventy-one patients with hematological malignancies (55%) or solid tumors (45%), neutropenia < 500/microliter, and fever > 38.5 degrees C were randomly assigned to either meropenem (1 g every 8 h) or ceftazidime (2 g every 8 h) and amikacin (15 mg/kg/day) intravenously. Meropenem (n = 34) and ceftazidime/amikacin (n = 37) were equivalent with respect to the clinical response at 72 h (62% versus 68%) (p > 0.05) and at the end of unmodified therapy (59% versus 62%). Gram-positive bacteremia responded poorly in the meropenem and ceftazidime/amikacin group (29% versus 25%), whereas all gram-negative bacteremias responded except for one in the meropenem group caused by Pseudomonas aeruginosa. All patients survived to 72 h. One patient in each group died of gram-positive sepsis resistant to study medication. No significant side effects occurred in any regimen. This study suggests that meropenem monotherapy might be as effective as combination therapy with ceftazidime and amikacin for the empirical treatment of febrile neutropenic patients.

Adolescent↗
PubMed1998

Analysis of in vivo correction of defined mismatches in the DNA mismatch repair mutants msh2, msh3 and msh6 of Saccharomyces cerevisiae.

We have analysed the correction of defined mismatches in wild-type and msh2, msh3, msh6 and msh3 msh6 mutants of Saccharomyces cerevisiae in two different yeast strain backgrounds by transformation with plasmid heteroduplex DNA constructs. Ten different base/base mismatches, two single-nucleotide loops and a 38-nucleotide loop were tested. Repair of all types of mismatches was severely impaired in msh2 and msh3 msh6 mutants. In msh6 mutants, repair efficiency of most base/base mismatches was reduced to a similar extent as in msh3 msh6 double mutants. G/T and A/C mismatches, however, displayed residual repair in msh6 mutants in one strain background, implying a role for Msh3p in recognition of base/base mismatches. Furthermore, the efficiency of repair of base/base mismatches was considerably reduced in msh3 mutants in one strain background, indicating a requirement for MSH3 for fully efficient mismatch correction. Also the efficiency of repair of the 38-nucleotide loop was reduced in msh3 mutants, and to a lesser extent in msh6 mutants. The single-nucleotide loop with an unpaired A was less efficiently repaired in msh3 mutants and that with an unpaired T was less efficiently corrected in msh6 mutants, indicating non-redundant functions for the two proteins in the recognition of single-nucleotide loops.

DNA Repair↗
PubMed1998

Clinical predictors easily obtained at presentation predict resource utilization in unstable angina.

OBJECTIVE: To determine if a risk prediction model for patients with unstable angina would predict resource utilization. METHODS AND RESULTS: Four hundred sixty-five consecutive patients admitted for unstable angina to a tertiary care university-based medical center were prospectively evaluated from June 1, 1992, to June 30, 1995. The proportion of patients receiving coronary angiography, coronary angioplasty, and coronary artery bypass grafting were analyzed according to four risk groups on the basis of a previously published model: Group 1, <2% risk of major complication; Group 2, 2.1% to 5% risk; Group 3, 5.1 % to 15% risk; and Group 4, >15.1 % risk. Hospital length of stay and estimated cost of hospitalization based on DRG and specific payer ratio of cost-to-charge were also compared between groups. Multiple linear regression analysis was used to determine the influence of estimated risk and procedures on hospital costs. The four groups were well matched for gender, hypertension, tobacco history, and previous percutaneous transluminal coronary angioplasty and myocardial infarction. Group 4 had a higher incidence of previous coronary bypass grafting (35% vs 10%, p=0.001) and triple vessel or left main coronary artery disease compared with Group 1 (44% vs 13%, p=0.041). Group 4 patients were more likely to be admitted to the coronary care unit compared with Group 2 or Group 1 patients (80% vs Group 1: 51% [p= 0.001]; and vs Group 2: 53% [p=0.001]), more likely to receive heparin (87% vs 71%, p=0.007), and more likely to receive a beta-blocker or calcium channel blocker (89% vs 74%, p=0.008) than Group 1. Coronary angioplasty rates were similar for all groups, but Group 4 patients were more likely to receive coronary bypass grafting than Group 2 or Group 1 (27% vs Group 2: 12%, p=0.004 and vs Group 1: 8%, p=0.002). Hospital length of stay was highest in Group 4 and lowest for Group 1. Average hospital costs were significantly less in Group 3 than in Group 4, but higher than in Group 1. Multivariate analysis determined a dependency of costs on risk group with Group 2 having costs 31.4% (95% CI=9.8 to 57.2), Group 3 46.7% (24, 3 to 73.1), and Group 4 75% (46.9 to 110.7) higher than Group 1. The use of procedures also significantly increased costs, with PTCA-treated patients having a 44.9% (26.7 to 65.7) increase in costs compared with medically treated patients, and surgically treated patients having a 204.7% increase in costs. CONCLUSION: Resource utilization as assessed by the use of revascularization procedures, length of stay, and hospital costs are influenced by patient acuity estimated from a prediction model on the basis of estimated risk of cardiac complications. The model exerts independent influence on cost even after adjustment for various procedures. The use of revascularization procedures, especially coronary artery surgery, remains a large determinant of hospital cost.

Adult↗
PubMed1998

Evaluating rapid diagnostic tests of intra-amniotic infection: Gram stain, amniotic fluid glucose level, and amniotic fluid to serum glucose level ratio.

OBJECTIVE: The aim of the study was to compare the diagnostic utility of the Gram stain, the amniotic fluid glucose level, and the ratio of amniotic fluid glucose level to serum glucose level in detecting intra-amniotic infection. STUDY DESIGN: We conducted a prospective study of 127 patients with preterm labor and 26 patients with preterm premature rupture of the membranes (153 total). All patients underwent amniocentesis to diagnose intra-amniotic infection. The diagnostic criterion for intra-amniotic infection was a positive amniotic fluid culture result. RESULTS: The Gram stain is 80% sensitive and 91% specific when a positive is considered the presence of white blood cells or bacteria. Amniotic fluid glucose level and the ratio of amniotic fluid glucose level to serum glucose level are significantly lower when amniotic fluid culture results are positive, but as diagnostic tests they are inferior to the Gram stain. Logistic regression models that combine predictors yield superior accuracy with respect to individual tests. The most accurate combination was amniotic fluid glucose level and Gram stain with white blood cells or bacteria. Although the number of patients with preterm premature rupture of the membranes was small in this study (n = 26), analysis of our data suggests that the diagnostic performance levels of these tests were similar when used in patients with preterm labor and intact membranes and in patients with premature rupture of the membranes. CONCLUSIONS: The amniotic fluid glucose level and the ratio of amniotic fluid to serum glucose level have equivalent diagnostic utility and are inferior to the Gram stain. The combination of Gram stain with amniotic fluid glucose level is superior to any individual test.

Adult↗
PubMed1998

Cytology and colposcopy after loop electrosurgical excision: implications for follow-up.

OBJECTIVE: To analyze risk factors associated with residual and recurrent lesions after loop electrosurgical excision procedure and to assess the reliability of cytology and colposcopy in detection of these lesions. METHODS: Cytology and colposcopy were used to follow up 288 women after treatment by loop electrosurgical excision 3-6 months, 9-15 months, and 24-36 months after the procedure. RESULTS: The mean (+/-standard deviation) postoperative follow-up was 39+/-13 months (range 24-68 months). Treatment failure, defined as the persistence or recurrence of a cervical lesion, was observed in 20 patients (6.9%). The endocervical localization of the initial lesion (adjusted relative risk [RR] 13.7; 95% confidence interval [CI] 1.3, 150.1; P < .05) and incomplete excision (adjusted RR 9.1; 95% CI 3.0, 27.3; P < .001) were the only independent risk factors for treatment failure. In six cases, a second treatment was performed before the first cytologic and colposcopic visit because of incomplete excisions. The remaining 14 treatment failures were diagnosed by postoperative cytology and colposcopy, ten after the first visit, three after the second, and one after the third. To diagnose the treatment failures, colposcopy and cytology provided complementary information at the first (P < .001) and second postoperative visits (P < .05). Although the sensitivity of cytology was not significantly improved by the association of both methods, the latter decreased the number of residual lesions overlooked by cytology alone and contributed to the diagnosis of 95% of treatment failures in less than 2 years. CONCLUSION: The high detection rate obtained by combining cytology and colposcopy during the first 2 postoperative years may allow more leisurely follow-up schedules after that time and may reduce the consequences of subsequent loss to follow-up.

Adenocarcinoma↗