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J Weber

Publications and source records attributed to J Weber.

At least 217 records · Page 12Linked to original sources
PubMed1997

Assessment of the reliability of cerebral potentials evoked by electrical stimulation of the anal canal.

The aim of this study was to assess the reliability of cortical evoked potentials after electrical stimulation of the anal canal. Cortical evoked potentials were recorded on 243 patients presenting with perineal pain (28 patients), impotence (55 patients), anal incontinence (52 patients), urinary continence (30 patients), constipation (49 patients), and on 29 neurological patients, by stimulating the external anal sphincter and penis (or clitoris). The inter- and intra-observer reproducibility was studied by coding recordings interpreted by three different observers on two separate occasions. The influence of recording characteristics and clinical data were assessed. To study operator dependence, five operators investigated the patients. Only one of them was well trained in this technique. The interpretation of the coded curves by the observers was poorly reproducible in about 15% of cases, depending on time between the two readings and the quality of recordings. The interpretation of cerebral responses after anal stimulation were observer-dependent and influenced by the knowledge of clinical data. This was also observed with cortical evoked potentials after electrical stimulation of the penis or clitoris, but to a lesser extent. The cerebral evoked potentials method was also operator-dependent, mainly after anal stimulation. When a study of cortical evoked potentials by perineal stimulation is needed in clinical practice, it seems logical to prefer cortical evoked potentials by penile or clitoral stimulation as they seem easier to obtain than those evoked by anal stimulation if the investigators are not well trained for the performance of electrophysiological studies as the former are much less operator- and observer-dependent.

Adult↗
PubMed1997

Difficult defaecation and/or faecal incontinence as a presenting feature of neurologic disorders in four patients.

We report four cases of difficult defaecation and/or faecal incontinence revealing a neurologic disease. These anorectal symptoms were associated with urinary disorders, but urinary symptoms always appeared several years after anorectal complaints. Clinical neurologic examination immediately led us to suspect a neurologic aetiology in two patients with the following signs: perineal hypoesthesia, absence of voluntary anal contraction and anal reflexes in one subject (final diagnosis: L1 neurinoma), and in the other a weakness in both thighs with absent tendon reflexes in the four limbs (final diagnosis: amiodarone neuropathy). In the two other patients with multiple cerebral infarction or multiple system atrophy, the neurologic aetiology was suspected on the absence of anal voluntary contraction contrasting with a normal perineal anatomy, but the final diagnosis was made only two years later when orthostatic arterial hypotension occurred.

Aged↗
PubMed1997

Colonic transit time in patients with myelomeningocele.

To evaluate colonic motility in patients with myelomeningocele, the transit time of radiopaque markers was studied in 22 patients with myelomeningocele and 22 age and sex matched controls. Mean colonic transit time was significantly longer in patients than in controls (103.2 +/- 49 h versus 23.3 +/- 13 h; P < 10(-7). Thirteen of 22 patients with myelomeningocele were severely constipated. Six patients had constipation secondary to delayed colonic transit, particularly in the left colon, and seven had increased rectosigmoid transit. The clinical questionnaire and particularly the frequency of bowel movements did not predict colonic transit. Among 13 patients with increased colonic transit, eight had more than five bowel movements per week and, thus, six of them did not use laxatives or enemas, despite the presence of faecal incontinence. There was no relationship between colonic transit time and the level of the spinal lesion or patient mobility in patients with myelomeningocele. Rectoanal dyssynergia was found in 14 of the 22 patients, but equally often in patients with delayed rectosigmoid transit (4/7) as in the other patients (10/15) (P = ns). Uninhibited detrusor contractions were observed more often in patients with increased colonic transit time than in others (8/12 versus 1/8, P = 0.05). In the absence of a correlation between colonic transit time, clinical symptoms, anorectal motility, level of spinal lesion, patient mobility, evaluation of colonic transit of radiopaque markers should be assessed routinely in all patients with myelomeningocele to plan the most appropriate treatment, mainly in case of unhibited detrusor contractions.

Adolescent↗
PubMed1997

[Spiral CT angiography in demonstration of cerebral aneurysms before and after treatment with titanium clips].

PURPOSE: To determine the suitability of spiral CT angiography (SCTA) in patients with intracerebral titanium aneurysm clips. MATERIAL AND METHOD: The section parameters were optimised using a phantom. 16 patients were examined preoperatively and 18 following treatment of aneurysms with clips. RESULTS: The resolution, sensitivity and specificity for demonstrating cerebral aneurysms measuring > or = 3 mm was 91.3% and 75% respectively. In 15 patients with intracerebral clips there were no or only minor artefacts; three examinations were of no value because of major metal artefacts. Amongst six aneurysms demonstrated angiographically, two, which measured more than 3 mm, could be shown by SCTA. CONCLUSION: SCTA was able to demonstrate intracerebral aneurysms measuring > or = 3 mm. Titanium clips did not usually affect image quality significantly.

Adolescent↗
PubMed1997

Fluence and mutagenic side effects of excimer laser radiation applied in ophthalmology in human lymphocytes in vitro.

PURPOSE: To investigate the influence of different fluences in 193 and 248 nm excimer laser radiation on the yields of chromatid and chromosome aberrations induced in human lymphocytes in vitro. METHOD: Heparinized human blood was exposed to 193 or 248 nm excimer laser radiation. The fluence was gradually increased from 21 to 400 mJ/cm2 in 193 nm (constant total energy of 250 J) and from 150 to 377 mJ/cm2 in 248 nm radiation (constant total energy of 500 J). Chromatid and chromosome aberrations were then analysed microscopically. RESULTS: The yields of chromatid breaks and achromatic lesions depend on the fluence per pulse. This dependence contains a linear component, indicating a threshold of about 70 mJ/cm2 fluence in 193 nm and of about 250 mJ/cm2 fluence in 248 nm laser radiation. An increase of the yield of dicentric chromosomes could only be observed at the highest fluence tested (377 mJ/cm2) in the 248 nm series. Over 126 mJ/cm2 in 193 nm radiation no lymphocytes could be cultured and therefore no aberrations could be found. CONCLUSIONS: Our findings show that the fluence of 193 nm and of 248 nm excimer laser radiation has an effect on the yields of chromatid breaks and achromatic lesions in human lymphocytes under in vitro conditions.

Adult↗
PubMed1997

Langerhans cell tropism of human immunodeficiency virus type 1 subtype A through F isolates derived from different transmission groups.

To test the hypothesis that some subtypes of human immunodeficiency virus type 1 (HIV-1), especially subtype E, are more likely to infect mature Langerhans cells (mLC), we titrated a panel of 26 primary HIV-1 isolates of subtypes A through F on peripheral blood mononuclear cells (PBMC) and mLC. The majority of HIV-1 isolates from heterosexually infected patients did not show a preferred tropism for mLC compared to homosexually transmitted HIV-1 isolates. Only 6 of 26 isolates, 2 from patients infected by homosexual contact and 4 from patients infected by heterosexual contact, showed a higher infectivity for mLC than for PBMC. Both syncytium-inducing and non-syncytium-inducing isolates were able to infect mLC which express mRNA for the chemokine receptors CCR3, CCR5, and CXCR4.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Genetic characterization of the role of the two HOX proteins, Proboscipedia and Sex Combs Reduced, in determination of adult antennal, tarsal, maxillary palp and proboscis identities in Drosophila melanogaster.

Both Proboscipedia (PB) and Sex Combs Reduced (SCR) activities are required for determination of proboscis identity. Here we show that simultaneous removal of PB and SCR activity results in a proboscis-to-antenna transformation. Dominant negative PB molecules inhibit the activity of SCR indicating that PB and SCR interact in a multimeric protein complex in determination of proboscis identity. These data suggest that the expression pattern of PB and SCR and the ability of PB and SCR to interact in a multimeric complex control the determination of four adult structures. The absence of PB and SCR expression leads to antennal identity; expression of only PB leads to maxillary palp identity; expression of only SCR leads to tarsus identity; and expression of both PB and SCR, which results in the formation of a PB-SCR-containing complex, leads to proboscis identity. However, the PB-SCR interaction is not detectable in vitro and is not detectable genetically in the head region during embryogenesis, indicating the PB-SCR interaction may be regulated and indirect. This regulation may also explain why ectopic expression of SCR(Q50K) and SCR do not result in the expected transformation of the maxillary palp to an antennae and proboscis, respectively. Previous analysis of the requirements of SCR activity for adult pattern formation has shown that ectopic expression of SCR results in an antenna-to-tarsus transformation, but removal of SCR activity in a clone of cells does not result in a tarsus-to-arista transformation. Here we show in five independent assays the reason for this apparent contradictory requirement of SCR activity in tarsus determination. SCR activity is required cell nonautonomously for tarsus determination. Specifically, we propose that SCR activity is required in the mesodermal adepithelial cells of all leg imaginal discs at late second/early third instar larval stage for the synthesis of a mesoderm-specific, tarsus-inducing, signaling factor, which after secretion from the adepithelial cells acts on the overlaying ectodermal cells determining tarsus identity. This study characterizes a combinatorial interaction between two HOX proteins; a mechanism that may have a major role in patterning the anterior-posterior axis of other animals.

Animals↗
PubMed1997

CPRs that cure.

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Cost-Benefit Analysis↗
PubMed1997

Bolus injection of MR contrast agents: hemodynamic effects evaluated by intracerebral laser Doppler flowmetry in rats.

PURPOSE: To determine the effects on arterial blood pressure and cerebral blood flow of intravenous bolus injection of three MR contrast agents: gadopentetate dimeglumine, polylysine-Gd-DTPA, and superparamagnetic iron particles (SPIO). METHODS: A single-fiber laser Doppler flowmetry probe was placed intracerebrally in 56 anesthetized rats. Cerebral blood flow and mean arterial blood pressure were measured before (baseline), during, and up to 30 minutes after intravenous bolus administration of the three contrast agents: 0.1 mmol/kg and 0.3 mmol/kg gadopentetate dimeglumine (n = 18 per group), 0.3 mmol/kg polylysine-Gd-DTPA (n = 10), and 0.03 mmol/kg SPIO (n = 10). RESULTS: Neither the higher nor lower dose of gadopentetate dimeglumine had any statistically significant effect on cerebral blood flow, and there was no change in blood pressure during administration of either dose of gadopentetate dimeglumine. Administration of polylysine-Gd-DTPA caused a transient drop in blood pressure in two animals, marked in one (decrease to 21% of baseline values) and mild in the other (84% of baseline). After administration of SPIO, a significant decrease in blood pressure occurred in one animal (41% of baseline). Despite this decrease in mean arterial blood pressure, there were no statistically significant changes in cerebral blood flow after administration of polylysine-Gd-DTPA or SPIO. CONCLUSION: Our results suggest that bolus injection of these contrast agents at clinically relevant doses causes no significant alteration in cerebral blood flow. We conclude that gadopentetate dimeglumine is well suited for cerebral MR perfusion imaging without inherent influence on cerebral blood flow and that the same is probably true for polylysine-Gd-DTPA and SPIO.

Animals↗
PubMed1997

Peptide inhibitors of HIV-1 and HIV-2 proteases: a comparative study.

HIV-1 and HIV-2 proteases (PR) which play the key role in the formation of infectious viral particles offer a target for inhibitors that could block the maturation step. Inhibitors o HIV-1 PR exhibit mostly 1-2 orders of magnitude weaker affinity for HIV-2 PR. The subsite specificity study of the HIV-1 and HIV-2 proteases performed with inhibitors varying in the type of nonhydrolysable bonds and amino acid residues in the P1, P1'and P2'positions has led us to the design of inhibitors with 2S,4S and 2R,4S stereomeres of the hydroxyethylene isostere and Glu or Gln in the P2'positions. These compounds inhibit HIV-1 and HIV-2 proteases in vitro in subnanomolar concentrations and exhibit the activity in tissue culture.

Animals↗
PubMed1997

[Why do adults with mucoviscidosis refuse a medically recommended course of intravenous antibiotic therapy?].

BACKGROUND: Regular courses of intravenous antibiotics are recommended for the treatment of chronic Pseudomonas aeruglnosa (PA) infection in patients with cystic fibrosis. We report the results of interviews performed to evaluate why a subgroup of patients vote against regular intravenous (i.v.) antibiotic treatment. METHODS: Structured interviews covering a) the individual's perception of chronic PA infection, b) the patient's expectations regarding the effectiveness of i.v. treatment, c) the patient's personal reasons for refusal of i.v. treatment. STUDY COHORT: 16 out of 18 adult patients treated in the adult CF outpatient clinic at Hannover Medical School who had voted against the physician's recommendation to receive regular i.v. therapy twice a year. RESULTS: More than one half of the patients did not regard chronic PA infection as important due to the lack of specific symptoms. A subgroup of patients had no idea of what their clinical status should be if i.v. antibiotics would be necessary; these patients reported prior experience of treatment courses which had been ineffective and had been instituted after talking into the patients. The most frequent reasons against IV treatment were not being sick enough and fear of adverse drug effects. ASSESSMENT: The results are being discussed considering the physician-patient relationship. The reasons why patients refuse help should be extensively explored rather than simply addressing this attitude as "non-compliance". Patients, too, come to reasonable decisions, and it is important to know their thoughts and reasoning if one intends to influence them.

Adult↗
PubMed1997

[EEG recordings during episodes of palinacousis and palinopsia].

Palinopsia (visual perseveration) and palinacousis (auditory perseveration) are reported in a 51-year-old woman with a left temporo parietal astrocytoma. EEG showed a left temporal delta-focus with sharp waves. EEG was not modified during neither palinacousis nor palinopsia. The relationship between the two hallucinatory phenomena and epilepsy is discussed.

Brain Neoplasms↗