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Biomedical subjects

B Meyer

Publications and source records attributed to B Meyer.

At least 145 records · Page 8Linked to original sources
PubMed1996

Surface morphology of basilar papilla of the tufted duck Aythya fuligula, and domestic chicken Gallus gallus domesticus.

Quantitative details of the surface morphology of the hearing organ, the Papilla basilaris, as seen in the scanning electron microscope are described for the tufted duck Aythya fuligula and for comparison for the domestic chicken Gallus gallus domesticus, for which some published information is already available. As in the other avian species investigated to date, each papilla shows a unique constellation of features. The papilla of the tufted duck is 3.5 mm long in the unfixed state and contains 8,200 sensory hair cells. It shows systematic changes in its surface features along the length and across the width of the sensory epithelium. In general, its features and those of the chicken Papilla basilaris can be described as relatively primitive in comparison with other species. The tufted duck papilla does, however, show one feature that has so far been found to be well developed only in advanced papillae; the number of stereovilli per hair cell bundle is generally much higher on hair cells of the neural than those on the abneural side. This difference is only weakly developed in the chicken. It is clear that features considered to be evolutionarily advanced were acquired independently of one another during evolution and that each bird species can show a mosaic of primitive and advanced features.

Animals↗
PubMed1996

The glial glutamate transporter complementary DNA in patients with amyotrophic lateral sclerosis.

Here, we report a mutation screening by single-stranded conformational analysis of the astroglial human brain glutamate transporter (HBGT) II complementary DNA in patients with amyotrophic lateral sclerosis. The conformational analysis data indicate a lack of sequence variations in the HBGT II coding region in 6 patients with amyotrophic lateral sclerosis and the same number of nonneurological control subjects. In both groups, three variants of the HBGT II 5' untranslated region were isolated. We have no evidence that the reported complementary DNA variants are disease specific.

ATP-Binding Cassette Transporters↗
PubMed1996

Magnetic resonance imaging assessment of labyrinthine pathology.

Membranous labyrinth pathologies are quite rare. They were until recently difficult to demonstrate by imaging technics, CT being the modality of choice. Our purpose was to stress the interest of MR examination for investigating patients complaining of vertigo, tinnitus, and profound sensorineural hearing loss. Normal anatomy as well as the main pathologically encountered changes are illustrated.

Ear Diseases↗
PubMed1996

The quantitative analysis of mixed crystals CuS(x)Se(1-x) with abrasive stripping voltammetry and a redetermination of the solubility product of CuSe and the standard potential of the Cu/CuSe electrode.

Phase identifications and quantitative analyses of mixed crystals by means of abrasive stripping voltammetry are reported using covelliteklockmannite (CuS(x)Se(1-x)) and emplectite-chalcostibite (CuBi(x) Sb(1-x)S(2)) mixed crystals as examples. The composition of CuS(x)Se(1-x) can be determined within a span of x=+/-0.03. Additionally the standard potential of the Cu/CuSe-electrode is measured to be E(. )(Cu/CuSe)= -0.749 V vs. Ag/AgCl.

Journal Article↗
PubMed1996

A cell for in situ incident-light microscopy for the study of electrochromism of solid state electrochemical reactions.

A cell is described which allows in situ incident-light microscopy to be used for the analysis of solid state electrochemical reactions studied by abrasive stripping voltammetry. The cell provides the possibility to screen solid compounds with respect to their electrochromic properties without requiring the preparation of special electrodes on transparent and conducting materials. Silver octacyanomolybdate(IV) and silver octacyanotungstate(IV) have been used to study the performance of the cell because both compounds exhibit a stable electrochromic and voltammetric behaviour.

Journal Article↗
PubMed1996

Fruit-specific expression of a defensin-type gene family in bell pepper. Upregulation during ripening and upon wounding.

We have isolated a 454-bp cDNA that encodes a novel fruit specific defensin from bell pepper (Capsicum annuum). The encoded 75-amino-acid polypeptide contains an N-terminal domain characteristic of a signal peptide and a 48-amino-acid mature domain named J1. The mature protein, from which the N-terminal amino acid sequence was determined, contains eight cysteines that from four intramolecular disulfide bridges, suggesting a monomeric form for J1. In healthy fruits J1 is undetectable at the green stage but high levels accumulate during ripening. In wound areas of the green fruit the accumulation of J1 dramatically increased, suggesting a role for J1 in the plant's defense response. Moreover, we have demonstrated that J1 possesses an antifungal activity. We have isolated and characterized the corresponding two homologous genes (j1-1 and j1-2) that exist in the bell pepper genome. Both genes are interrupted by the insertion, at the same position, of one intron of 853 bp for j1-1 and 4900 bp for j1-2. Northern blot and reverse transcriptase-polymerase chain reaction and restriction fragment length polymorphism analyses revealed that j1-1 transcripts are present only in fruits, only in trace amounts in mature green fruits, and that they accumulate to high levels in fully ripe fruits, whereas no j1-2 transcripts were detected in the samples monitored.

Amino Acid Sequence↗
PubMed1996

Free fatty acids and gestational diabetes mellitus.

Dyslipidaemia is a common finding in the syndrome of gestational diabetes mellitus (GDM). Free fatty acids (FFA) can cause insulin resistance and have a toxic effect on beta cell function. GDM is a syndrome due to insulin resistance and the purpose of this study was to examine FFA levels in pregnancy. For this purpose samples were taken from 44 consecutive women with GDM and 36 consecutive controls. The women with GDM had similar levels of insulin, triglycerides and total cholesterol to the controls but a significant elevation in FFA; 0.70 (0.33) mmol/L versus 0.29 (0.12) mmol/L (p < 0.0001).

Adult↗
PubMed1996

Intrinsic tumors of the insula: a prospective surgical study of 30 patients.

Intrinsic insular tumors are frequently excluded from surgical treatment. The authors propose a more extensive approach to these lesions based on the results of this prospective series. From September 1993 to January 1995, 30 patients (18 males and 12 females; mean age 42 years) harboring benign (15 patients) or malignant (15 patients) tumors involving the insula underwent surgical treatment. The dominant and nondominant hemispheres were both affected in 15 cases. Two groups were defined on the basis of preoperative magnetic resonance (MR) imaging: 14 lesions were restricted to the insula and the corresponding opercula; the other 16 lesions also involved other mesocortical and/or allocortical areas. Most patients displayed only mild preoperative symptoms. The median score according to the Karnofsky performance scale was 90. Microsurgical removal was achieved via a transsylvian approach in nine cases and via a frontal and/or temporal approach in 21 cases. According to early postoperative MR imaging, complete tumor removal (100%) was seen in five patients, nearly complete (> 80%) in 21, and incomplete resection (50%-80%) in four patients. There was no operative mortality; 19 patients (63%) experienced immediate postoperative morbidity, including reduced performance. After a mean follow-up review of 8.5 months two of 21 patients suffered permanent deficits, accounting for an overall operative morbidity of 10%. At the mean time of review, three patients with Grade IV tumors had died of tumor recurrence. The authors conclude that low-grade intrinsic insular tumors, as well as Grade III tumors, can be removed with favorable results in the majority of patients. Surgery to excise glioblastomas should only be considered for patients with good preoperative performance and young age.

Adult↗
PubMed1995

[Initial results with laparoscopic fundoplication].

17 patients underwent laparoscopic Nissen fundoplication for gastroesophageal reflux disease not responding to medical treatment. Conversion to laparotomy was necessarily due to large paraesophageal hiatus hernia (3) or severe peri-esophagitis (1) in 4 patients. There was no perioperative morbidity or mortality. At 3 months all patients were symptom-free. Esophageal manometry revealed a rise in mean lower esophageal sphincter pressure from 4 mm Hg preoperatively to 11 mm Hg postoperatively, and lengthening of the high pressure zone from 2.3 to 3.3 cm. One patient needed reoperation one year after fundoplication due to wrap disruption with recurrent reflux disease. Laparoscopic fundoplication involves low perioperative morbidity and shortens the postoperative recovery time in selected patients.

Adult↗
PubMed1995

Characterization of a family of genes encoding a fruit-specific wound-stimulated protein of bell pepper (Capsicum annuum): identification of a new family of transposable elements.

Using a fruit-specific cDNA as a probe we isolated and sequenced the two corresponding homologous genes (Sn-1 and Sn-2) of the bell pepper (Capsicum annuum) genome. Both genes have a single intron and numerous unusual long inverted repeat sequences. The introns share 87% homology and Sn-2 contains one 450 bp additional sequence with structural features of a transposable element, which is highly repetitive in the bell pepper genome. Surprisingly, analysis in data banks showed that genes encoding the potato starch phosphorylase (EC 2.4.1.1) and patatin contain a similar element, named Alien, in their 5'-upstream region. Alien elements are characterized by a conserved 28 bp terminal inverted repeat (TIR), small size, high AT content, potential to form stable DNA secondary structures and they have probably been inserted in TA target sites. Interestingly, the TIR of the Alien elements shares high homology with sequences existing in the TIR of extrachromosomal linear pSKL DNA plasmid of Saccharomyces kluyveri. Northern blot analyses detected Sn-1 transcripts principally in the red fruit whereas no Sn-2 transcripts were detected in neither of the samples monitored. Western blot analyses detected a 16.8 kDa Sn protein principally in the ripe red fruit and wounded areas of green unripe fruit. A comparison of the deduced amino acid sequence of Sn-1 with protein sequences in data banks revealed a significant homology with proteins likely involved in the plant's disease resistance response. Analyses at the subcellular level showed that Sn-1 is localized in the membrane of vacuoles.

Amino Acid Sequence↗
PubMed1995

Posterior inferior cerebellar artery aneurysm in the fourth ventricle.

We report a patient with a ruptured aneurysm of the choroidal branch of the right posterior inferior cerebellar artery (PICA), lying in and causing an isolated haemorrhage in the fourth ventricle. MRI on the first day after bleeding revealed an abnormal vessel in the fourth ventricle, which was surrounded by a mass of intermediate signal on T1- and T2-weighted images. The aneurysm was clipped via partial splitting of the lower vermis and opening the inferior medullary velum. A postoperative angiogram confirmed complete obliteration of the aneurysm. With PICA aneurysms the rate of intraventricular haemorrhage is high and in most cases due to reflux of blood. If there is an isolated intraventricular haemorrhage, a peripheral PICA aneurysm, lying in or near the fourth ventricle, may be suspected.

Cerebellum↗
PubMed1995

The C-reactive protein for detection of early infections after lumbar microdiscectomy.

The tendency for short hospitalization after lumbar microdiscectomy implies the need for early confirmation or disapproval of serious postoperative infections such as spondylodiscitis or deep wound infections. The C-reactive protein (CRP) is a well-known screening parameter for monitoring postoperative infectious complications in other fields. Our objective was to establish the diagnostic significance of CRP-in comparison with ESR and WBC-for monitoring infectious complications after lumbar microdiscectomy. Over a 15 months period we studied prospectively a homogeneous group of N = 400 patients with lumbar disc herniations who were operated on a single level for the first time. CRP, ESR and WBC values were determined in all patients pre-operatively, and on postoperative days 1 and 5. Clinical and laboratory findings were correlated and the diagnostic significance of CRP, ESR and WBC calculated. N = 385 (96%) patients had an uneventful postoperative course. N = 15 (4%) patients developed infectious complications, of which N = 6 (1.5%) were unrelated and N = 9 (2.5%) related to surgery. Evaluation of the laboratory values showed: The CRP baseline is a very individual value of no prognostic relevance. A high postaggression peak is typical and essential as a reference value for only the future time course will disclose any infection. We found 0% false negative and 4% false positive results on day 5. The sensitivity for serial CRP testing was calculated as 100% and specificity as 95.8%. ESR (sensitivity: 78.1%/specificity: 38.1%) and WBC (sensitivity: 21.4%/specificity: 76.8%) both failed to reach such distinct diagnostic significance on day 5. The C-reactive protein has thus proved to be a reliable, simple and economical screening test for infectious complications after lumbar microdiscectomy, superior to classical laboratory parameters.

Adolescent↗
PubMed1995

Amount of subarachnoid blood and vasospasm: current aspects. A transcranial Doppler study.

Subsequent to admission after aneurysmal subarachnoid haemorrhage (SAH), 120 patients (74 women and 46 men) underwent microsurgical clipping of a total of 158 cerebral aneurysms within 96 hours after the bleed. Their mean age was 46 (20-91) years. Computed tomography (CT) findings were graded according to the modified Fisher scale and all patients had daily transcranial doppler (TCD) recordings of their basal cerebral arteries. In 19% of SAH was grade I on CT, in 44% grade II and in 37% grade III. The rate of patients who developed severe vasospasm as documented by TCD (mean blood flow velocities exceeding 160 cm/s on 2 or more consecutive days) was 39% for grade I patients, 26% for grade II patients and 34% for patients with SAH grade III on the initial CT. There was no difference in the rate of occurrence of severe vasospasm, when the patients were split into 2 groups according to the time of performance of the initial CT scan-within 24 hours, and 48-80 hours after SAH, respectively. It is concluded that the amount of subarachnoid blood on the initial CT scan should no longer be used as the indicator for occurrence and severity of the multifactorial entity vasospasm.

Adult↗
PubMed1995

Combined antenatal vitamin K and phenobarbital therapy for preventing intracranial hemorrhage in newborns less than 34 weeks' gestation.

UNLABELLED: ōk--q----_xD-xD whether maternal antenatal therapy with vitamin K and phenobarbital prevents intracranial hemorrhage in premature newborns. METHODS: Women at high risk for spontaneous or indicated premature delivery before 34 weeks' gestation were randomly assigned to receive either placebo or vitamin K and phenobarbital. All patients received betamethasone and antibiotics and were managed uniformly by a single perinatal group in one hospital. All newborns were managed uniformly in the same nursery by one neonatal group. Two independent interpretations of neonatal head ultrasound examinations were obtained. RESULTS: The duration of gestation at study entry and at delivery were similar in the placebo (181 mothers) and treatment (191) groups. With the hospital radiology group (the primary interpreter), the incidence rates of severe intracranial hemorrhage (8 versus 7%) and mild intracranial hemorrhage (38 versus 32%) were similar for both groups. With the secondary interpreter (a single pediatric radiologist), the incidence rates of severe intracranial hemorrhage (9 versus 7%) and mild intracranial hemorrhage (27 versus 26%) were also similar. Neonatal mortality was equivalent in both the placebo and treatment groups (8 versus 10%). CONCLUSION: Combined antenatal therapy with vitamin K and phenobarbital does not reduce the frequency or severity of intracranial hemorrhage in premature newborns.

Adolescent↗