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Biomedical subjects

O Thulesius

Publications and source records attributed to O Thulesius.

At least 91 records · Page 5Linked to original sources
PubMed1986

Generation and transmission of ovine ureteral contractions, with special reference to prostaglandins.

The pattern of spontaneous rhythmic contractions was studied in isolated preparations from calyx, pelvic, middle and distal parts of the sheep ureter. The frequency of contractions was highest in intrarenal specimens (13.3 +/- 0.8 contractions min-I). The regional difference in contractions is consistent with proximal dominant pacemaker cells. In isolated rings, indomethacin (10(-5) M) inhibited and finally stopped rhythmic motility. After stoppage prostaglandin PGF2 alpha (10(-6)-10(-5) M) promptly re-established contractions in a manner characteristic of each specimen, apparently according to the pre-existent dominant pacemaker (frequency and pattern). This was demonstrated in a frequency analysis which showed a highly significant correlation of pacemaker frequencies before and after indomethacin. Experiments using dual recordings from both ends of a longitudinal preparation (tandem mode) showed that co-ordinated contractile waves travelling from one end to the other could be initiated with PGF2 alpha. These results have been interpreted to indicate that prostaglandins in ureteral smooth muscle play a predominant role in co-ordinating intercellular impulse transmission for which gap junctions could be responsible. The presence of such structures, as clearly demonstrated by an ultrastructural study, lends support to this hypothesis.

Animals↗
PubMed1986

New evidence for prostaglandin induced motility of the ureter.

In the search for particular ultrastructural features which could be responsible for the persistent rhythmic contractility in sheep ureteral preparations we detected a large number of extracellular electron dense granules in the lamina propria of the ureter. These structures are very similar to lipid granules previously described in the renal papilla of the rat and man. Ureteral motility is blocked by indomethacin and prostaglandins are powerful stimulators of rhythmic contractions. Tissue extracts from the ureter contain substances which exhibit smooth muscle stimulating properties as shown in bioassays. Evidence is presented which shows that the ureteral granules contain lipid material which could be the source (precursor) of smooth muscle stimulating factors, probably prostaglandins.

Animals↗
PubMed1986

Dihydroergotamine therapy in orthostatic hypotension due to psychotropic drugs.

A double-blind, placebo controlled study with 10 mg per day dihydroergotamine in patients with orthostatic hypotension induced by treatment with psychotropic drugs showed a significant effect in preventing immediate drop in blood pressure after standing up. Preventing an abrupt drop in blood pressure with change of posture hinders symptoms of dizziness and faintness and helps activating patients who otherwise prefer to stay in bed.

Antidepressive Agents, Tricyclic↗
PubMed1986

Measurements of serum gentamicin concentrations by a biological method, fluorescence polarization immunoassay and enzyme multiplied immunoassay.

Serum gentamicin levels were assayed in patients receiving the aminoglycoside to determine dosage adjustments. The accuracy and reproducibility of three methods were compared; bioassay, enzyme multiplied immunoassay (Syva EMIT) and fluorescence polarisation immunoassay (Abbott TDx). Each assay method offered acceptable precision. The bioassay method correlated well with both the enzyme multiplied immunoassay and the fluorescence polarisation immunoassay (correlation coefficients 0.854 and 0.937, respectively). The automated methods provide results within 15 min and are not influenced by combinations of antibiotics, hence they are the methods of choice for aminoglycoside determinations.

Biological Assay↗
PubMed1985

Adverse drug reaction monitoring in Kuwait (1981-1984).

The methodologic, operational, and medical aspects of general population spontaneous adverse drug reaction (ADR) monitoring system organized in the State of Kuwait between June 1981 to June 1984 are described. The objectives of the study were to outline the procedures required for the establishment of a national ADR center in addition to studying the pattern of ADRs. Ethnic and sociocultural variables were factors influencing the frequency of adverse effects. A computer data base was created to handle incoming reports. A total of 704 reports were received from 26 hospitals and health clinics; the majority (90.5%) were classified as having a possible positive causal relationship. Anti-infectives were the most commonly reported drugs (32.2%), and cutaneous reactions were encountered most often (48.6%). Serious drug-induced reactions have been identified. Intake of nifedipine adversely affected glucose tolerance among diabetic and nondiabetic subjects. Bromocriptine causal sexual dysfunction was reported among women. Cimetidine and ethambutol were associated with optic neuritis and blindness. Metoclopramide and prochlorperazine resulted in dystonic reactions in children. Based on this study, the health authorities in Kuwait indicated their intention to establish a national ADR center.

Adolescent↗
PubMed1985

The effect of indomethacin on the motility of isolated sheep ureters.

The possible spasmolytic effect of indomethacin was studied on isolated sheep ureteral preparations. Ureteral ring preparations suspended in an organ bath exhibited long lasting rhythmic contractions quite similar to the in vivo situation. This spontaneous motility was unaffected by hyoscine, phenoxybenzamine, propranolol, mepyramine and methysergide. Addition of indomethacin resulted in a dose dependent reduction in amplitude and frequency of the contractions, the threshold value being 10(-8) M. Washing reestablished motility and both PGE2 and PGF2 alpha were powerful stimulators of rhythmic contractions. Our conclusion is that in vitro rhythmic activity of the ureter is dependent on endogenous PG-synthesis and the cyclooxygenase inhibitor indomethacin dose-dependently blocks this.

Animals↗
PubMed1985

Motility of the human ureter, with special reference to the effect of indomethacin.

Ureteral motility was studied in isolated preparations obtained from 19 patients at surgery. Contraction was monitored in an organ bath and contraction recorded isometrically. In all but one patient rhythmic activity with a frequency of 2.0 +/- 0.3 contractions/min was recorded. In 6 patients contractions had to be elicited by stimulation with prostaglandin E2 or F2 alpha. In the remaining cases motility started spontaneously within 30 min. In patients with bilharzia nephropathy various pathological types of contraction were recorded. Motility was dose-dependently inhibited with indomethacin.

Dinoprost↗
PubMed1983

Vascular effects of hyperthermia on isolated blood vessels.

1. The contractile response of isolated human umbilical and sheep renal arteries to 5-hydroxytryptamine (5-HT) with increasing temperatures was investigated. 2. In the umbilical artery the threshold value was lowest at 30 degrees C and increased with increasing temperature, the maximal response being lower at temperatures above 30 degrees C. 3. Spontaneous rhythmic contractions of the umbilical artery were not augmented by warming above 37 degrees C. 4. The sheep renal artery exhibited an opposite response pattern: increasing temperature lowered the threshold and increased the maximal response. 5. Addition of indomethacin to the bathing fluid resulted in increased responsiveness of the umbilical arteries to 5-HT. With lower threshold, ED50 and higher maximal response.

Animals↗
PubMed1983

Vascular effects of potassium cardioplegic solutions.

Experiments have been performed on isolated human umbilical and sheep coronary arteries, studying the effects of increasing potassium concentration in steps from 10 to 160 mM. Comparative studies were also done on rat-heart papillary-muscle preparations. The results revealed a dose-dependent increase in smooth muscle tone of the blood vessels. Maximal contraction was reached at 80 mM K+. Papillary-muscle preparations showed a dose-dependent decrease in contractile activity. Complete stoppage of contractile activity was observed at 30 mM K+. The corresponding increase in the vascular smooth muscle tone at 30 mM K+ was 10-25%, showing that vascular smooth muscle cells are less easily affected by increasing K+ than the heart. Further confirmation of the results were obtained by exposing the preparations (papillary muscle and arteries) to a locally-developed depolarizing K+-cardioplegic solution.

Animals↗
PubMed1983

Contractile response of isolated human vessels with special regard to stretch and storage.

The effect of stretch and storage of isolated human blood vessels was studied in vitro. The following observations were made. 1. Umbilical vessel preparations exhibited spontaneous rhythmic activity whereas other vessels showed this only after storage. Amplitude but not frequency of this activity increased after stretching. 2. Innervated vessel preparations showed increased sensitivity and maximal response to noradrenaline after storage. This can probably be explained by denervation supersensitivity and receptor upregulation and the rhythmic responses after storage may reflect unstable membrane potentials and prostaglandin synthesis.

Electric Stimulation↗