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Biomedical subjects

S Meyer

Publications and source records attributed to S Meyer.

At least 55 records · Page 3Linked to original sources
PubMed2004

Epidemiological assessment of 160 cases of insulin overdose recorded in a regional poisons unit.

OBJECTIVE: Overdoses with insulin are common, and cases of hypoglycemic coma can be fatal and cause cerebral defects. However, data published on this topic are rare, consisting mostly of case reports or reports in a small number of patients. The present investigation analyzes inquiries made to a regional poisons unit involving overdoses with insulin. PATIENTS AND METHODS: A total of 175,890 inquiries for the years 1995-2003 (until September) were evaluated. 160 inquiries were received by telephone concerning insulin overdoses, and a standardized questionnaire was sent to the physicians asking for follow-up information. The cases were analyzed in regard to etiology, type of insulin used, concomitant substances being taken by the patient, symptoms and clinical outcome. RESULTS: Of the 160 inquiries investigated, 53.1% of the patients were female, 43.1% male and in 3.8% the sex of the patient was unknown. The average age was 44.7 years. 89.4% involved suicidal or parasuicidal cases, 5.0% were accidental overdoses and 1.9% involved cases of criminal overdose (3.7% were for other reasons). Rapidly acting insulins (57.8%) were used more commonly than long-acting formulations (42.8%). Benzodiazepines were the most frequently ingested concomitant medication (37.5%) with ethanol 15.6%, antihypertensive drugs 12.5% and antidepressants 10.0%. Most patients presented with a delay of 2-3 hours after insulin administration (15.0%). Almost 50% of the patients presented within the first 6 hours. According to the Poisoning Severity Score, no symptoms were observed in 16.8% of the patients, minor symptoms in 36.8%, major symptoms in 25.2% and serious symptoms in 21.3%. Information concerning the clinical outcome (75 cases) showed that a full recovery occurred in most patients (94.7%), but in 2.7% there were cerebral defects and 2.7% of the patients died. CONCLUSIONS: The etiology of overdoses with insulin was mainly deliberate self-poisoning. Physicians should take into account that long-acting insulin formulations and concomitant substances were frequently used. For overdoses with insulin, relatively high rates of serious symptoms and deaths were observed.

Adult↗
PubMed2003

Nematic ordering of suspension of charged anisotropic colloids detected by multinuclear quadrupolar spectra and 1H PGSE-NMR measurements.

The structure of aqueous dispersion of charged anisotropic nano-composites (synthetic Laponite clays) have been studied by NMR and numerical simulations based on a multi-scale statistical analysis have been used to interpret the mobility of the confined water molecule diffusing within dense Laponite aqueous dispersions (29-52% w/w) prepared by uniaxial compression. Firstly, the lineshape detected by NMR quadrupolar spectroscopy of the counterions ((23)Na or (7)Li) exhibits a large residual splitting Delta nu which is the fingerprint of the macroscopic nematic ordering of the anisotropic particles. Secondly, these results are also confirmed by the anisotropy of the self-diffusion tensor of the water molecule measured by (1)H Pulsed Gradient Spin Echo NMR. This self-diffusion anisotropy increases with the suspension density. Thirdly, the multi-scale statistical analysis of the water mobility bridges the gap between the time-scale (ps) accessible by Molecular Dynamics simulations and the time-scale (micros) accessible by Brownian Dynamics, leading to macroscopic behaviour comparable with PGSE-NMR data measurements.

Journal Article↗
PubMed2003

[Endosonographically controlled transluminal fine needle aspiration biopsy: diagnostic quality by cytologic and histopathologic classification].

BACKGROUND AND OBJECTIVE: EUS-guided fine needle aspiration (EUS-FNA) has emerged as a highly accurate technique for detecting and classifying mediastinal and pancreatic lesions as well as abdominal and recently retroperitoneal masses with a minimum of risk for the patient. PATIENTS AND METHODS: To objectify these statements, we evaluated the quality of 72 EUS-FNA specimens by cytologic and histopathologic classification, investigated their contamination with tissue from the needle pathway and observed puncture-related complications in a retrospective study of 44 EUS-FNA in 41 consecutive patients (56 +/- 14 years, m = 24, f = 17; 13 pancreatic, 9 adrenal, 6 abdominal and 13 mediastinal masses). EUS-FNA was performed using a PENTAX 32 UA endosonoscope (longitudinal 7.5 MHz sector array) in combination with a needle system type "Hancke-Vilmann". RESULTS: 16 vs. 11 of 34 histopathologic and 38 cytologic specimens were classified "excellent", 7 vs. 10 "sufficient", 7 vs. 13 "poor" and 4 vs. 4 "failed". Analysis of contamination with tissue from the needle pathway showed 4 vs. 2 specimens "highly", 3 vs. 14 "clearly", 8 vs. 19 "slightly" and 19 vs. 3 "not" contaminated. Specimens classified "excellent" were less contaminated (p = 0,037). EUS-FNA identified 35 benign and 24 malignant masses. Definite diagnosis failed in 13 specimens. One nonfatal complication occurred. EUS-FNA is an accurate (89 %) and low-risk procedure to examine primary undiagnosed mediastinal, pancreatic, intraabdominal and especially adrenal lesions in most of the cases. Contamination with tissue from the needle pathway seems to be a major predictive factor of poor specimen quality and failed diagnosis. CONCLUSION: EUS-FNA expands the diagnostic approach of mediastinal, abdominal, pancreatic and adrenal masses and provides accurate specimens for reaching new differential-diagnostic competence, especially in endocrinologic cases.

Abdominal Neoplasms↗
PubMed2003

Phylogenetic analysis of rubella virus including new genotype I isolates.

Infection during the first trimester of gestation with rubella virus (RV) is highly teratogenic. Embryopathy is a frequent outcome of the primary natural infection with wild type RV during pregnancy while accidental immunisation with life attenuated vaccine has apparently little or no adverse effect. Although the nucleic acid sequence of RV is exceptionally stable, differences between the vaccine and wild type viruses could play a role in the pathogenesis of intrauterine RV infection. Phylogenetic analysis of eight complete sequences (including two new isolates described in this paper, three vaccine strains, three cell culture adapted wild type viruses) confirms a striking low divergence of the RV genome. A variable region (amino acid residues 697-800) within the gene coding for the nonstructural protein NSP1 was defined. Phylogenetic analysis revealed a strong positive selection in this region. Multiple passages in vivo or in vitro did not account for this variability. As the function of the variable region has not yet been elucidated, reasons for and significance of positive selection are still speculative. It is conceivable that the variable region in NSP1 contributes to the molecular basis of RV embryopathy and other complications of postnatal RV infection.

Animals↗
PubMed2003

Expression of Tie-2 in human peripheral and autonomic nervous system.

Tie-2, a tyrosine kinase receptor, is essential for vascular integrity by regulating cellular adhesion between pericytes and endothelial cells. The aim of this study was to identify sites of expression of Tie-2 other than the vasculature. Tie-2 expression was first detected in human colon by Western blotting and reverse-transcription-polymerase chain reaction (RT-PCR) in tissue extracts. The presence of the Tie-2 mRNA and protein was detected by immunohistochemistry and in situ hybridization in cells of the colon myenteric and submucosal plexus, in both neuronal and Schwann cells. Tie-2 protein was also found in the nervous system of the female urogenital tract. In the human sciatic nerve and schwannoma, RT-PCR, Western blotting and immunohistochemistry analysis further confirmed the presence of Tie-2 mRNA and protein in non-autonomic peripheral nervous tissue. In conclusion, using several approaches and tissues we have demonstrated the presence of Tie-2 in human peripheral and autonomic nervous tissue, suggesting a role for Tie-2 in neural tissue. Thus, attempts to disrupt the tumour vessels by manipulation of the Tie-2 system in tumours may result in side-effects in peripheral nerves.

Colon↗
PubMed2003

[Model project of hearing screening in new-born in Hanover (preliminary results)].

In Germany, congenital hearing disorders are usually detected too late resulting in insufficient therapy of the disorder. To investigate these problems, the Federal Ministry of Health and the principal associations of statutory health insurance commissioned a pre-operative study. The study's aim is to verify whether introduction of a universal new-born hearing screening results in earlier diagnosis of hearing disorders and thus improves medical care for children with impaired hearing. Feasibility, effectiveness and economic tenability of this hearing screening programme will be investigated. The study is realised in the Hanover region and aims at carrying out a hearing test in all new-born during the first days of life. The tests will be performed in all 10 birth clinics and 2 paediatric clinics in the relevant region and in 24 otolaryngological practices. Hearing ability is controlled via an automated screening device measuring otoacoustic emissions. Sensitivity and specificity of the test is more than 95%. Economical feasibility is investigated by cost-effectiveness analyses. During a 6-month period the screening has been implemented in all clinics in every day routine. The mean coverage rate in the clinics has been stabilised to 97% of the total number. 4.7% of the children were presumed to suffer from unilateral hearing disorders and 2.3% from bilateral. In 13 cases the diagnosis of hearing disorder was confirmed. The mean age of diagnosis in these children was 3.7 months. The average age of therapy onset was 4.4 months. According to the present experience, area-wide implementation of hearing screening seems feasible in existing health care structures. The intention to advance the time of diagnosis and the therapy onset can be achieved by this method. Systematic training, introduction and quality assurance measures of screening are mandatory. Tracking of suspicious cases is necessary, even if it challenges data privacy regulations.

Cost-Benefit Analysis↗
PubMed2003

UV-induced blue-green and far-red fluorescence along wheat leaves: a potential signature of leaf ageing.

Under UV-excitation, leaves emit red (RF) and far-red (FRF) fluorescence from chlorophyll and blue-green fluorescence (BGF) from hydroxycinnamic acids. In this study, the aim was to develop a fluorescence signature of wheat leaf ageing after the emergence of the lamina. FRF and BGF were examined in the first three leaves of 2-week-old wheat plants. It was investigated how FRF and BGF vary as leaf and tissue aged by spectroscopic measurements, time-resolved BGF analysis and microscopic imaging of the leaf surface. It was found that FRF decreased with leaf and tissue ageing because of an accumulation of UV-absorbers in the epidermis. BGF also decreased, but without changes either in the shape of excitation and emission spectra or in the fluorescence lifetime. So, BGF emanated from the leaf surface, without changes in fluorophore composition during leaf ageing. The shape of the BGF spectrum indicates that ferulic acid bound to the cell wall is the main blue-green fluorophore. The effects of pH and solvents on BGF from intact leaves and ferulic acid in solution were similar, confirming the hydroxycinnamic acid origin of BGF. UV-fluorescence microscopic imaging of the surface of intact leaves showed that different epidermis cell types and sclerenchyma bands emitted BGF. The decreasing gradient of BGF from the base to the apex of the lamina could be related to the decrease in the surface of the fluorescent sclerenchyma bands. The significance of FRF and BGF as potential signatures of wheat lamina growth are discussed.

Apoptosis↗
PubMed2003

Location-dependent patterns in cardio-autonomic dysfunction in ischaemic stroke.

BACKGROUND AND STUDY PURPOSE: Autonomic nervous system dysfunction is a common complication of acute cerebrovascular disorders. The aim of this study was to investigate a possible location-dependent difference in cardio-autonomic function in patients with ischaemic stroke. PATIENTS AND METHODS: Sympathetic function was prospectively assessed by determining plasma norepinephrine and epinephrine in 19 patients with left-hemisphere (LH), 14 with right-hemisphere (RH) and 6 with brainstem/cerebellar (BS) stroke. Blood pressure, heart rate, cardiac output and transcranial flow velocity in the middle cerebral artery were recorded during the first 5 days after stroke. RESULTS: Stroke caused an initial increase in sympathetic function in all 3 groups with a spontaneous decrease in norepinephrine in LH (p < 0.01) and BS stroke (p < 0.05) only. Norepinephrine was significantly higher in RH than in BS stroke (p < 0.05). The alterations in autonomic function were paralleled by a sustained elevation in cardiovascular parameters mainly in RH stroke. CONCLUSIONS: Plasma catecholamines are feasible in monitoring location-dependent autonomic dysfunction in ischaemic stroke. Hemispheric lateralization in autonomic control should be taken into account in the management of stroke because of an increased susceptibility to cardio-autonomic dysfunction in patients with RH stroke.

Aged↗
PubMed2003

Inhibitors of the Plasmodium falciparum parasite aspartic protease plasmepsin II as potential antimalarial agents.

Malaria is a very serious infectious disease against which the currently available drugs are loosing effectiveness. The main problem is the emergence and the spreading of resistant parasite strains. New treatments are needed in order to regain control over the disease. Drug discovery efforts towards this goal are likely to be more successful, if they focus towards novel mechanisms of action. Such efforts will result in drugs that are functionally and structurally different from the existing drugs and therefore will overcome existing resistances. Here we focus on the aspartic protease plasmepsin II, which is a promising new drug target. We review the drug discovery efforts that were published in the literature on this enzyme, and we present the compounds synthesized at Actelion Pharmaceuticals Ltd.

Animals↗
PubMed2002

Platinum agents in the treatment of osteosarcoma: efficacy of cisplatin vs. carboplatin in human osteosarcoma cell lines.

BACKGROUND: Cisplatin (cDDP), when used either alone or, more often, in combination with other agents, especially adriamycin, achieves a high response rate in osteosarcoma. Its use, however, is limited by severe nephro- and neuro-toxicity. Second generation platinum compounds, most notably carboplatin (CBDCA), have been developed in order to attempt to reduce these dose-limiting toxicities, and thus improve the therapeutic ratio. Studies evaluating the role of combination CT containing CBDCA vs. cDDP have demonstrated differing results depending on the tumor type tested and its role in the treatment of osteosarcoma has yet to be clarified. PROCEDURE: In this study, we compared the in vitro anti-tumor activity of cDDP and CBDCA in a panel of three human osteosarcoma cell lines (HOS, MG63, and U2OS). RESULTS: cDDP and CBDCA (0-20 micromol) showed marked variation in cytotoxicity among the three cell lines. EC(50) values for CBDCA in HOS and MG63 cells were approximately two-fold higher than for cDDP and the ratio of AUC(CBDCA) to AUC(cDDP) varied from 1.8 in the HOS cell line to 2.3 in the MG63 cell line. Exposure of MG63 and HOS cells to either cDDP or CBDCA (1.67 and 13.5 micromol) caused a G2/M cell cycle arrest by 24 hr. Also evident was a sub G1 peak indicative of cell death by apoptosis. U2OS cells were relatively resistant to the cytotoxic effects of both drugs, although a cell cycle arrest in response to DNA damage was observed. This suggests that unlike MG63 and HOS cells, U2OS cells have either a more efficient repair pathway for platinum-induced DNA damage or are able to evade apoptosis. Examination of apoptotic events and cellular recovery demonstrated that both an 8-16-fold higher concentration and longer treatment period for CBDCA compared with cDDP was required to produce equivalent cell death and a loss of the ability of single cell clones to form colonies in both the HOS and MG63, but not the U2OS cell line. CONCLUSIONS: Our findings suggest that CBDCA at a two- to four-fold higher concentration than cDDP has potential therapeutic activity in platinum sensitive osteosarcomas, particularly when cDDP cytotoxicity compromises therapeutic efficacy.

Antineoplastic Agents↗
PubMed2002

[Meningioangiomatosis with associated meningioma in a 4-year-old girl presenting with a focal seizure].

Meningioangiomatosis is regarded as a rare, benign, hamartomatous malformation. Histopathologically, the lesion is characterized by circumscribed transcortical and leptomeningeal meningovascular proliferation with focal calcifications. It may be classified into cases with predominant cellular or vascular features and may occur in association with neurofibromatosis, mostly of type 2, but sporadic cases are more frequently reported. Sporadic cases often present initially with seizures and can be treated surgically. However, a certain percentage of patients will need ongoing anticonvulsive therapy. The lesions are seldom associated with an overlying meningioma. These are usually benign lesions that must be strictly separated from an invasive anaplastic meningioma, which would warrant an adjuvant therapy. We report on a 4-year-old girl who presented with spontaneous, predominantly cellular meningioangiomatosis with associated fibrous meningioma. Focal immunopositivity of the meningioangiomatosis for CD34 was helpful in ruling out an invasive meningioma.

Antigens, CD34↗
PubMed2002

Effects of epidural analgesia on pelvic floor function after spontaneous delivery: a longitudinal retrospective study.

The aim of the study was to assess the effects of epidural analgesia on pelvic floor function. Eighty-two primiparous women (group 1, consisting of 41 given an epidural, and group 2 of 41 not given an epidural) were investigated during pregnancy and at 2 and 10 months after delivery by a questionnaire, clinical examination, and assessment of bladder neck behavior, urethral sphincter function and intravaginal/intra-anal pressures. The prevalence of stress urinary incontinence was similar in both groups at 2 months (24% vs. 17%, P = 0.6) and 10 months (22% vs. 7%, P = 0.1), as was the prevalence of decreased sexual vaginal response at 10 months (27% vs. 10%, P = 0.08). Bladder neck behavior, urethral sphincter function and intravaginal and intra-anal pressures showed no significant differences between the two groups. Ten months after spontaneous delivery, there were no significant differences in the prevalence of stress urinary incontinence and decreased sexual vaginal response, or in bladder neck behavior, urethral sphincter function and pelvic floor muscle strength between women who had or had not had epidural analgesia.

Adult↗
PubMed2002

Impact of non-detects in water quality data on estimation of constituent mass loading.

Often, fractions of stormwater constituents are not detected above laboratory reporting limits and are reported as non-detect (ND), or censored data. Analysts and stormwater modelers represent these NDs in stormwater data sets using a variety of methods. Application of these different methods results in different estimates of constituent mean concentrations that will, in turn, affect mass loading computations. In this paper, different methods of data analysis were introduced to determine constituent mean concentrations from water quality datasets that include ND values. Depending on the number of NDs and the method of data analysis, differences ranging from 1 to 70 percent have been observed in mean values. Differences in mean values were, as shown by simulation, found to have significant impacts on estimations of constituent mass loading.

Environmental Monitoring↗
PubMed2001

Phytanic acid and docosahexaenoic acid increase the metabolism of all-trans-retinoic acid and CYP26 gene expression in intestinal cells.

Retinoids are essential for growth and cell differentiation of epithelial tissues. The effects of the food compounds phytol, the phytol metabolite phytanic acid, and the fatty acid docosahexaenoic acid (DHA) on the retinoid signaling pathway in intestinal cells were studied. Phytol inhibited the formation of all-trans-retinoic acid (RA) from dietary retinol in intestinal cells. Phytanic acid, a known retinoic X receptor (RXRalpha) and peroxisome proliferator activating receptor (PPARalpha) activator, also activated PPARdelta, and to a lesser degree PPARgamma, in a transactivation assay. Phytanic acid had no effect on intestinal RA hydroxylase CYP26 (also named P450RAI) gene expression and metabolism of all-trans-RA in intestinal Caco-2 cells. However, in combination with retinoic acid receptor (RAR)-ligands (all-trans-RA or synthetic Am580) phytanic acid enhanced the induction of CYP26 and RA-metabolism in comparison to treatments with all-trans-RA or Am580 alone. Also treatment with DHA did not affect CYP26 gene expression and RA-metabolism but cotreatment of the cells with DHA and all-trans-RA or Am580 enhanced the induction of CYP26, in comparison to the induction caused by all-trans-RA or Am580 alone. This study indicates that food compounds such as phytanic acid and DHA that are RXR-agonists and have an impact on intestinal CYP26 gene expression and metabolism of all-trans-RA in intestinal cells.

Benzoates↗
PubMed2001

[Transplants from the shoulder-back region].

BACKGROUND: In spacious or multilayered tissue losses and cases of multiple locations of defects, a large amount of tissue with different components such as skin, fatty tissue, and muscle is required for proper reconstruction. A donor area which can meet these demands is the shoulder-back region with the subscapular vessel, which arises from the axillary artery. PATIENTS AND METHODS: We report our clinical experience with 12 patients in whom we reconstructed defects with transplants from this region. RESULTS: Our anatomic investigation and measurements provided proof of a constant anatomy of the vessels with a length of the vascular pedicle and a vascular diameter suitable for microvascular anastomosis. Based on our clinical experience, the scapular, parascapular, and latissmus dorsi muscle transplants are very suitable for the reconstruction of very large superficial defects or for the augmentation of multilayered defects of the upper aerodigestive tract. CONCLUSIONS: A main advantage of the transplants from the shoulder and back region is the possibility of combining several transplants with a wide variety of tissue combinations with one vascular pedicle for a single-step reconstruction of multiple defects of the oral cavity and the pharynx.

Anastomosis, Surgical↗
PubMed2001

Pelvic floor education after vaginal delivery.

OBJECTIVE: To assess the effect of pelvic floor education after vaginal delivery on pelvic floor characteristics in nulliparous women. METHODS: We examined 107 nulliparas during pregnancy and at 9 weeks and 10 months after vaginal delivery. Methods used included a questionnaire, clinical examination, perineosonography, urethral pressure profiles, and intravaginal and intra-anal pressure recordings during pelvic floor contraction. After the second examination, the women were assigned in alternating manner to either 12 sessions of pelvic floor exercises with biofeedback and electrostimulation (n = 51) or no training (n = 56). The two groups were compared at the third examination. RESULTS: Stress urinary incontinence incidence decreased in 2% of control subjects compared with 19% of women who underwent pelvic floor education (P =.002), whereas the incidence of fecal incontinence (5% versus 4%, P = 1) and the percentage of women who recovered predelivery pelvic floor contraction strength (33% versus 41%, P =.4) were no different. We observed no significant differences in bladder neck position and mobility, urethral functional length, maximal urethral closure pressure, pressure transmission ratio, residual area of continence at stress standing, or intravaginal or intra-anal pressures during pelvic floor contraction between groups at the third examination. CONCLUSION: Pelvic floor education, begun 2 months postpartum, significantly reduced the incidence of stress urinary incontinence, but not fecal incontinence or weak pelvic floor. Similarly, bladder neck behavior, urodynamic characteristics, intravaginal or intra-anal pressures during pelvic floor squeezing also were not modified.

Adult↗