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Biomedical subjects

A Donath

Publications and source records attributed to A Donath.

At least 55 records · Page 3Linked to original sources
PubMed1985

A simple method for measurement of intestinal calcium absorption in humans by double-isotope technique.

We describe a method for the fast calculation of total fractional calcium absorption (TFCaA) by the double-isotope technique (45Ca orally and 47Ca intravenously). The gamma- and beta-activities of plasma or urine samples were measured simultaneously. 47Ca activity was obtained by a gamma-ray spectrometer after exclusion of scandium 47. The 45Ca activity was measured directly by subtracting the 47Ca plus 47Sc component from the total beta-activity. In addition, 45Ca activity was determined after 8 weeks, to allow for 47Ca and 47Sc decay. There was good correlation between these two methods of measuring 45Ca activity. TFCaA was calculated both by deconvolution taken as a reference method and from the equilibrium quotient 45Ca/47Ca observed in several blood or urine samples collected at different times. The most convenient sampling time for calculation of this ratio was reappraised, taking into account the type of solution ingested orally (water or milk). The results indicate that simultaneous counting of gamma- and beta-activities of an appropriate plasma or urine sample provides a good and rapid measure of the calcium absorption. This method is considered to be useful as a clinical tool.

Adult↗
PubMed1984

[Global ventricular function and synchronism of contraction during and after exertion].

Phase analysis and ejection fraction (EF) of the left ventricle were obtained by radionuclide angiography in 53 patients at rest, during submaximal exercise and 3-8 minutes after exercise. The standard deviation of the peak of the histogram of phases (SDP) was used as an index of the synchronicity of regional contraction. The material comprised 13 sportsmen and 40 patients who underwent coronarography, 12 of whom had normal coronaries and 28 significant lesions. EF, while comparable in the three groups at rest, increased significantly on effort in normals and did not change in patients with coronary disease. At rest SDP was higher in coronary patients than in normals (p less than 0.01), and during exercise, it increased, but decreased in normals (p less than 0.01). After exercise, mean EF decreased in comparison with exercise in normals (p less than 0.01), while the opposite was the case in coronary patients. Normals had lower SDP values in the post-exercise period than at rest; on the other hand, SDP of coronary patients was significantly higher in the post-exercise period than at rest (p less than 0.001). Phase analysis during, and particularly after, exercise was found to be superior to EF in detecting ischemic left-ventricular dysfunction, and should be used in conjunction with EF to evaluate patients suspect for coronary disease.

Adult↗
PubMed1984

[Application of computerized tomoscintigraphy in the detection of tumors using cobalt-57-marked bleomycin].

57Co-bleomycin scanning dates from the early 1970s, when the first results were presented by Renault et al. Since then there have been numerous publications concerning the high sensitivity of this type of study in the detection of pulmonary or cerebral neoplasms. In the region below the diaphragm, however, sensitivity was poor due to hyperactivity of the kidney, liver and bladder. To eliminate this problem the authors have used single photon emission computerized tomography (SPECT), and their department is currently investigating the sensitivity of this technique for the detection of neoplasms. Two typical cases are described which illustrate the value of this method in the detection of cancer.

Abdominal Neoplasms↗
PubMed1984

[Dichloromethylene diphosphonate in the treatment of lytic bone metastases].

Dichloromethylene diphosphonate (Clodronate) has powerful activity against osteoclasts. We studied its effects on calcium balance in patients with malignant osteolytic lesions. Ten normocalcemic patients with advanced metastatic bone disease or myeloma were evaluated in a baseline 20-day calcium balance and kinetic study. They were then randomized to a clodronate or placebo regimen, treated intravenously for two weeks and orally for a month, and finally re-evaluated in another 20-day balance and kinetic study, conducted while they were still receiving treatment. The results show that both calcium balance and calcium absorption increased from base line in the clodronate group and that these changes were significantly different from those in the placebo group. There was a marginal decrease in bone resorption in the clodronate group and no change in bone accretion. Our results suggest that clodronate may be a useful adjuvant in managing metastatic bone disease.

Adult↗
PubMed1983

[Diagnosis of internal abscesses by scintigraphy: results of a method using purified granulocytes].

In the 111-indium-leukocyte scan method described by M. L. THAKUR et al. in 1977 for the diagnosis of abdominal abscesses the whole leukocyte fraction from a blood sample is labeled and injected into patients. We propose a modification in which purified granulocytes are used. The results of 43 granulocyte scans show that this modification does not diminish the sensitivity of the method. Furthermore, it allows the detection of abscesses in a shorter time (2-4 hours after injection) and with 111-indium doses (200 muCi) at least 3 times lower than in the original method. Increased specificity can also be expected.

Abdomen↗
PubMed1983

Use of dichloromethylene diphosphonate in metastatic bone disease.

Dichloromethylene diphosphonate (clodronate), a new compound, has powerful activity against osteoclasts and has been used successfully to treat hypercalcemia associated with cancer. We studied its effects on calcium balance in patients with malignant osteolytic lesions. Ten normocalcemic patients with advanced metastatic bone disease or myeloma were evaluated in a baseline 20-day balance and calcium kinetic study. They were then randomized to a clodronate or placebo regimen, treated intravenously for two weeks and orally for a month, and finally reevaluated in another 20-day balance and kinetic study, conducted while they were still receiving treatment. The results show that both calcium balance and calcium absorption increased from base line in the clodronate group and that these changes were significantly different from those in the placebo group (mean change [+/- S.D.] in calcium balance [clodronate vs. placebo], 203.8 +/- 140.1 vs. -65.2 +/- 98.8 mg [5.1 +/- 3.5 vs. -1.6 +/- 2.5 mmol] of calcium per day, P less than 0.01; change in calcium absorption, 158.8 +/- 158 vs. -38.2 +/- 96.0 mg [4.0 +/- 4.0 vs. -1.0 +/- 2.4 mmol] per day, P less than 0.05). There was a marginal decrease in bone resorption in the clodronate group and no change in bone accretion. Our results suggest that clodronate may be a useful adjuvant in managing metastatic bone disease.

Bone Neoplasms↗
PubMed1983

Effects of lactose on intestinal calcium absorption in normal and lactase-deficient subjects.

The effect of lactose on intestinal calcium absorption was studied in 12 normal-lactase subjects and 7 lactase-deficient subjects. Calcium absorption was compared by using the double isotope technique with or without the presence of an oral load of 50 g of lactose in each subject. The kinetic parameters were measured by the deconvolution method. In the normal lactase group, the lactose prolonged the duration of absorption at a maximum rate and therefore increased the total fractional calcium absorption from 0.224 +/- 0.039 to 0.356 +/- 0.076 (p less than 0.001). In the lactase-deficient subjects, the lactose decreased the total absorption from 0.255 +/- 0.039 to 0.209 +/- 0.032 (p less than 0.005); this effect resulted in a decrease of the maximum absorption rate. There was no significant difference between the two groups when calcium was ingested alone. These results indicate that the effect of lactose on calcium absorption is dependent on intestinal lactase activity.

Adult↗
PubMed1983

Bioavailability of Theodel, a new theophylline tablet, in humans.

The bioavailability of Theodel, a new scored tablet of theophylline, was investigated in eight healthy adult volunteers. Rate of absorption and AUC infinity were compared after single oral doses of Theodel (250 mg), of an aqueous solution (250 mg), and of two Theolair tablets (2 X 125 mg). Theophylline was rapidly absorbed from the Theodel tablet, with a t1/2abs of 0.44 +/- 0.37 h; maximum plasma concentrations of 8.0 +/- 2.3 mg/l were reached after 1.8 +/- 0.8 h. Almost the entire dose was recovered from urine as theophylline and its major metabolites, 1,3-dimethyluric acid, 1-methyluric acid, and 3-methylxanthine. Theophylline was, therefore, efficiently absorbed from this formulation. The plasma elimination half-life ranged from 5.9 to 10.4 h. Based on the assumption that absorption is complete, the plasma clearance ranged from 0.028 to 0.048 1 X h-1 X kg-1, and the apparent volume of distribution from 0.38 to 0.57 1/kg. No significant difference between the rate and the extent of theophylline absorption was observed for the three preparations, which are thus bioequivalent. Simulations of plasma levels after repeated administration of Theodel tablets showed that plasma theophylline concentrations remain in the therapeutic range with three doses per day.

Adult↗
PubMed1981

Clinical evaluation of simultaneously administered 58Co labelled vitamin B12 and 57Co labelled vitamin B12 bound to intrinsic factor in patients with pernicious anaemia.

The clinical and laboratory data from 75 patients with altered vitamin B 12 absorption were reviewed. In 36 cases the diagnosis of pernicious anaemia had been established. Of these, 14 patients showed malabsorption of radiolabelled vitamin B 12, but the absorption of vitamin B 12 bound to the intrinsic factor (IF) was normal (Group A). The other 22 patients with pernicious anaemia showed altered free and IF-bound vitamin B 12 absorption (Group B). Laboratory and clinical data and the absorption tests (xylose and fat excretion) were more abnormal in group B than in group A. Finally, 39 patients (Group C) with general malabsorption showed alternation of the absorption of free and IF-bound vitamin B 12 (Group C). The clinical nd biological data were different in these patients from that found in groups A and B. It is possible that in patients with pernicious anaemia who are untreated an alteration of the intestinal mucosa may produce a malabsorption of vitamin B 12 even in the presence of intrinsic factor.

Anemia, Pernicious↗
PubMed1981

Urinary metabolites of oxapadol (MD720111), a new non-narcotic analgesic agent, in the rat, dog and man.

1. A number of metabolites of oxapadol were isolated from urine of rat, dog and man after administration of a single dose of 14C-labelled compound. They were identified by direct inlet mass spectrometry and chromatographic comparison with reference compounds. 2. Oxapadol was extensively metabolized and the unchanged drug was undetectable in rat or human urine; only traces were found in dog urine. Nine metabolites were identified in rat and dog urine, and six in man. 3. The routes of biotransformation were: (a) aromatic hydroxylation, mainly in the benzimidazole ring, (b) scission of the heterocyclic ring following two different pathways, and (c) a combination of the two. Regioselectivity was observed for aromatic hydroxylation, as only three of the four possible monohydroxy oxazepinobenzimidazoles could be detected.

Adult↗
PubMed1981

Mechanical versus pharmacologic prevention of deep venous thrombosis.

The prevention postoperatively of deep venous thrombosis was studied using three different regimens in 227 patients undergoing surgical procedures. Seventy-six patients received 5,000 units of heparin subcutaneously and 0.5 milligrams of dihydroergotamine twice a day. In 76 patients, intermittent pneumatic compression of the legs was applied preoperatively and postoperatively with active physiotherapy. The last 75 patients received subcutaneously 5,000 units of heparin each eight hours. Systematic deep venous thrombosis detection was carried out using both the 125I fibrinogen test and the Doppler method, being confirmed by phlebography if positive. The 125I fibrinogen test proved to be more sensitive and more specific. The incidence of deep venous thrombosis and pulmonary embolism were comparable in the groups, mechanical prophylaxis being as effective as the two other regimens. No side-effects were noted with the use of intermittent compression boots. A venoconstricting agent associated with heparin may permit smaller doses with the same prophylactic effect.

Adult↗
PubMed1980

[Overall and regional sensitivity of myocardial thallium-201 scintigraphy compared with the number and location of coronary lesions and the presence of previous myocardial infarction].

An evaluation is presented of (1) the overall sensitivity and specificity of 201Tl myocardial scintigraphy in 230 patients with suspected coronary artery disease and (2) the effects of the number and location of the diseased vessels, and the presence of previous infarction, on regional sensitivity in 151 patients. Overall sensitivity was 91% (80%, 95%, 97%) in patients with 1, 2 or 3 vessels respectively. Overall specificity was 81% or 89% if 7 patients with infarction and normal coronaries were excluded. In 80% of patients with one diseased vessel, in 41% of patients with 2 diseased vessels, and in only 24% with 3 diseased vessels were all lesions detected. 201Tl scintigraphy detected 52% of circumflex lesions as compared to 75% of right coronary and 74% of left anterior descending lesions. Of the 151 patients with proven coronary disease, 75 had a previous infarction. Overall and regional 201Tl sensitivity were greater (but not significantly) in this subgroup as compared to patients without myocardial infarction.

Adult↗
PubMed1980

[Regional myocardial perfusion in coronary stenosis of varying degrees].

Stenoses of the left anterior descending coronary artery of varying severity (15-73% of internal diameter, 20-95% of internal surface) were created in 25 open-chest pigs. The regional distribution of myocardial blood flow perfusion was studied by the radioactive microspheres technique at rest and during reactive hyperemia. Reactive hyperemic responses to 10 sec occlusions were used to produce maximal flow increases and to judge the physiological significance of the narrowings in the subendocardial and subepicardial layers in calculating coronary flow reserves. Measurements of coronary reserve are sensitive indices of functional impairment even when resting flow is unimpaired. At 75% stenosis the subendocardial coronary reserve is completely abolished and the zone perfused by the stenosed artery is unable to increase its flow when needed if the experimental conditions do not change. Any further increase in oxygen demand will provoke electrical and metabolic disorders. For abolition of the subepicardial coronary reserve a 94% stenosis is required.

Animals↗
PubMed1980

[Use of strontium-89 in the analgesic treatment of bone metastases].

The analgesic properties of 89Sr were investigated in 17 patients with multiple painful bone metastases. 89Sr is a radioisotope, the metabolism of which in the body is comparable to that of calcium. It is a pure beta emitter and its half-life is 51 days. When injected intravenously it is captured by bone, especially at locations where the turnover is increased. Each patient received 1--2 mCi of 89Sr. Bone scans and hematological investigations were performed before, and 2 months after, treatment. No significant changes were found. Shealy's method was used to assess pain, initially twice a week and then at more prolonged intervals. One patient suffering from multiple myeloma showed a spectacular improvement and 6 others responded favourably. Improvement generally occurred within 3--7 days, but was sometimes delayed for up to 3 weeks. Relief lasted for up to several months. Five patients had an increase of pain during the 24 hours immediately after treatment. An average of 28% of the administered radioactive dose was found in the urine collections during the first 48 hours. Although the treatment was not successful in every case, the use of 89Sr as a long acting analgesic in multiple bone metastases should be considered more frequently, especially as there are no side effects.

Aged↗