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Biomedical subjects

R Widmer

Publications and source records attributed to R Widmer.

17 recordsLinked to original sources
PubMed1996

Ambulatory 24-hour jejunal motility in diarrhea-predominant irritable bowel syndrome.

BACKGROUND: Whether small-bowel motility is abnormal in the irritable bowel syndrome (IBS) is a controversy at present. The aim of our study was to compare ambulatory long-term jejunal motility in 35 IBS patients with predominant diarrhea to normal values obtained in 50 healthy controls. METHODS: Twenty-four-hour motility was recorded in the proximal jejunum with a portable datalogger and tube-mounted miniature pressure sensors. Fasting motility in the waking (W) and sleeping (S) state and the motor response to a standardized evening meal of 600 kcal underwent visual and computer-aided analysis. RESULTS: Fasting motility in patients showed migrating motor complex (MMC) cycles of normal length and composition. Uninterrupted runs of discrete clustered contractions during phase II (W) occurred in 57% of patients and 52% of controls but had a significantly longer duration in patients (33 +/- 5 versus 19 +/- 7 min; p < 0.005). During phase II (W) IBS patients had an increase in aborally propagated contractions (41 +/- 2% versus 35 +/- 2%; p < 0.01) and higher contraction amplitudes (26.3 +/- 0.8 versus 23.0 +/- 0.5 mm Hg; p < 0.01). Similar differences were obtained during postprandial motility (47 +/- 3% versus 39 +/- 3%; p < 0.01, and 25.9 +/- 0.9 versus 23.8 +/- 0.05 mm Hg; p < 0.02). In three patients (8.6%) disturbed aboral migration of phase III and irregular burst activity, manometric features of chronic idiopathic intestinal pseudo-obstruction, were identified. Whereas 57% of patients had an entirely normal 24-h manometry, 43% had at least one finding not present in any healthy control. CONCLUSION: Small-intestinal motility is frequently but not universally abnormal in diarrhea-predominant IBS. The abnormal manometric findings are heterogeneous and range from subtle quantitative changes to severe qualitative abnormalities resembling chronic idiopathic intestinal pseudo-obstruction in a small subset of patients.

Adult↗
PubMed1995

Use of the Escherichia coli chromosomal DHFR gene as selection marker in mammalian cells.

The folA gene, the chromosomal dhfr gene of Escherichia coli, was engineered for expression in mammalian cells. In contrast to plasmid-derived bacterial dhfr genes previously used as selection markers in mammalian cells, the folA gene product is inhibitable by methotrexate (MTX) and trimethoprim (TMP). Therefore, this dhfr may present an alternative to mammalian dhfr species currently used as amplifiable selection markers. Transfected E. coli folA dhfr could complement the lack of endogenous DHFR in Chinese hamster ovary (CHO) cells lacking a functional dhfr gene. Both MTX and TMP inhibited growth of E. coli folA dhfr-transfected CHO cells. Expression of E. coli folA DHFR could be visualized by incubating the transfected cells with a fluorescent methotrexate derivative (F-MTX). Binding of F-MTX to E. coli folA DHFR was inhibitable as by both MTX and TMP, whereas MTX but not TMP blocked binding of F-MTX to recombinant mouse DHFR.

Animals↗
PubMed1995

Production of the chimerical plasminogen activator K2tu-PA in CHO cells.

Development of a CHO cell-based production system for the hybrid plasminogen activator K2tu-PA is described. Using the major immediate-early promoter of mouse cytomegalovirus (MCMV) transient and stable expression levels were 3-10-fold higher than those obtained with several other strong promoters. Splicing and polyadenylation signals from the rabbit beta-globin gene were used downstream of the DNA segment coding for K2tu-PA. The strong enhancer moiety of the MCMV promoter also stimulated strongly the promoter of the dihydrofolate reductase (DHFR) gene, placed adjacently for selection/gene amplification purposes. One construct with opposing K2tu-PA and DHFR RNA transcripts yielded the highest expression level with a single copy of the plasmid, but K2tu-PA expression was consistently lost after amplification of such genes, possibly as a result of the formation of antisense RNA. With other constructs, K2tu-PA production leveled off at 6.5 micrograms per million cells per day despite a high gene copy number. This was due to a combination of inefficient mRNA translation and mRNA instability, caused by elements from the untranslated portions of tissue-type and urokinase-type plasminogen activator cDNA which were included in the expression vector. After elimination of these inhibitory DNA segments, 4-5-times higher expression levels were reached.

Animals↗
PubMed1994

Effect of the quaternary ammonium compound trospium chloride on 24 hour jejunal motility in healthy subjects.

This study aimed to record 24 hour jejunal motility in healthy ambulant subjects and to analyse changes in motility caused by the oral administration of an anticholinergic agent, the quaternary ammonium compound, trospium chloride. In a placebo-controlled, double blind crossover trial, 24 hour jejunal motility was recorded in 12 healthy volunteers, aged 25 (21-30) years, using a digital data logger connected to two strain-gauge transducers mounted 20 cm apart in a flexible nasojejunal catheter. A computer program was developed to determine contraction parameters. Trospium chloride (15 mg orally thrice daily) prolonged the duration of irregular contractile activity after meals (p < 0.02) and reduced its contraction frequency and amplitude (p < 0.001). In the fasting state, the cycle length of the migrating motor complex was prolonged (p < 0.01) by an extended phase I (p < 0.025). Phase III was shortened (p < 0.005) and showed a slower aboral migration velocity (p < 0.005). Clustered contractions were less frequent during postprandial and fasting periods (p < 0.01). Runs of clustered contractions were completely absent with trospium chloride. Digital manometry was useful for long term recordings of jejunal motility and enabled the motor effects of an anticholinergic agent to be characterised in ambulant subjects.

Adult↗
PubMed1994

Computerized analysis of ambulatory long-term small-bowel manometry.

BACKGROUND: Ambulatory long-term manometry is increasingly being used to study small-bowel motility. This study aimed to develop computer-aided data analysis including the elimination of artefacts, identification of individual phasic contractions, and analysis of aboral propagation. METHODS: Data processing included low-pass filtering, base-line adaptation, cross-comparison of channels, and application of threshold values for contraction parameters. Automated analysis was validated by a visual reference standard. RESULTS: Artefacts were related to cardiovascular and respiratory activity, changes in body posture, and contractions of the abdominal wall. Automated recognition of contractions reached a sensitivity of 92% and a positive predictive value of 88% compared with the visual standard. Mean contraction amplitude and duration of computer analysis were 96% and 93%, respectively, of the visually obtained values. Propagation analysis under ambulatory conditions showed good agreement with previous results by stationary recordings. CONCLUSIONS: Computerized analysis provided valid and reproducible data on small-bowel phasic contractile events and propagative activity by digital long-term manometry.

Adult↗
PubMed1987

Adjuvant intravesical chemotherapy of superficial bladder cancer with monthly doxorubicin or intensive mitomycin. A comparison of two consecutive series.

120 patients with the first occurrence of TNM stage Ta or T1 bladder carcinoma were given adjuvant intravesical treatment in 2 consecutive series. The first 60 received doxorubicin monthly for 6 months, then on the 9th and 12th month following surgery. The second series was given mitomycin weekly for 2 months, then monthly to the end of the first year. Median follow-up is 48 months in the first series and 15 in the second. In the doxorubicin group, 28 patients had recurrences. The recurrence rate is 1.86/100 patient-months. Seventeen of these first relapses occurred within the first year. In the 'intensive' mitomycin series, where 36 patients were observed for 12 months or more, 3 relapsed. The recurrence rate to date is 0.35. The relapse-free survival probability at 12 months is 75% in the first series and 93% in the second. Treatment was stopped due to toxicity in 4 patients in the doxorubicin group and in 10 of the mitomycin group.

Administration, Intravesical↗
PubMedDate not supplied

Anxiety in family practice.

The time course of patient initiated visits, somatic, functional, and other medical complaints was studied in a group of 58 patients from a family practice who had been diagnosed and treated for anxiety. The findings were contrasted with two other groups of patients from the same practice: 101 depressives and 101 controls. Results indicate that the anxiety patients differed markedly from the depressives in having a very short-lived episode of anxiety or somatic complaints in contrast to depressives' much longer history of somatic and functional complaints which appeared to precede by months the diagnosis of depression. The findings suggest that the anxiety patients in this practice either had a qualitatively different condition from the depressives, or possibly suffered from a short-lived and unrecognized depression.

Anxiety Disorders↗