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Biomedical subjects

D Luft

Publications and source records attributed to D Luft.

35 records · Page 2Linked to original sources

Definition of clinically relevant lactic acidosis in patients with internal diseases.

In order to define clinically relevant lactic acidosis, 12 biochemical variables, eight clinical symptoms and signs, leading diagnoses, and mortality were evaluated prospectively in approximately 2,000 unselected patients with internal diseases, consecutively admitted to the hospital. Patients with incomplete data sets were not considered. Of those patients who repeatedly were admitted to the hospital during the time of the study, only the first admission was included for statistical analysis. In addition to 11 definitions of lactic acidosis given in the literature, sequential cluster analyses of the biochemical variables were used to estimate the incidence of lactic acidosis in 1,467 patients. Depending upon which definition was used, 0.5-3.8% of all patients were classified as suffering from lactic acidosis, with a mortality rate ranging from 30-88%. From this study it is concluded that a limit of less than or equal to 7.35 for pH and of greater than 5-6 mmol/L for the concentration of lactate in whole blood will minimize false-negative or false-positive classifications.

Acidosis

["Hyperthyroiditis" (author's transl)].

Typical signs of so-called hyperthyroiditis are hyperthyroidism, low iodine uptake by the thyroid, absence of local, general or humoral signs of inflammation, and absence of significant antibody titres against thyroid tissue. These features are illustrated by the case report of a 51-year-old man. Since the course of hyperthyroidism is short and has a good prognosis, the importance of the diagnosis lies in avoiding unnecessary therapeutic measures. This cause of hyperthyroidism can be recognized only by including tests of intrathyroid iodine metabolism among diagnostic procedures.

Antibodies

[Carbohydrate infusion in internal diseases. A comparative study in metabolically healthy patients, patients with liver diseases and diabetic patients. I. Physiopathologic aspects in the parenteral administration of monosaccharides].

The biochemical basis of the metabolism of glucose and non-glucose-carbohydrates (fructose, sorbitol, xylitol) is presented. The potential draw backs of the parenteral application of large doses of these carbohydrates in internally ill patients, based on the results of experiments with isolated perfused livers or animals and case reports, are reviewed. These considerations form the basis for investigations in internally ill patients (liver cirrhosis, diabetes mellitus) and healthy controls in order to find out if low dose, long term, parenteral infusion of glucose or mixtures of glucose with non-glucose-carbohydrates are applicable to these patients without major side effects. The results of these investigations will be published in following papers.

Blood Glucose

Lactic acidosis in biguanide-treated diabetics: a review of 330 cases.

The paper presents an analysis of clinical symptoms, signs and laboratory data of 330 diabetic patients who developed lactic acidosis after having been treated with biguanides (phenformin, buformin, metformin). From the review of the literature an attempt is made to find special features that predisposed patients to develop lactic acidosis such as accompanying illnesses and additional medications, to describe the course of illness and also the factors that influenced the prognosis. Of the patients that developed lactic acidosis 50.3% died. These patients were older, they suffered more frequently from cardiovascular shock, their acidosis was more severe, the whole blood lactate concentration was higher, and the degree of renal insufficiency was more advanced. From our observations we conclude the the treatment of diabetes mellitus with biguanides should be reserved for specially selected patients.

Acidosis

[Treatment of diabetic coma and precoma with continuous low-dose insulin infusions (author's transl)].

13 patients, nine women and four men, aged 22 to 83 years, were treated for diabetic coma or precoma between September 1974 and January 1976. Ten patients were known diabetics and six of them had been treated with insulin. On admission blood sugar was 32.4 +/- 3.3 mmol/l (5.84 +/- 0.6 g/l). The capillary blood pH was 7.15 +/- 0.06 (n = 13). Treatment consisted of continuous insulin infusion (6 IU soluble insulin/hour), physiological saline, potassium substitution and sodium bicarbonate (if the pH was below 7.15). In the first hours of treatment 98 +/- 12IU of insulin, 6.5 +/- 0.5 litres of fluid, 168 +/- 22 mmol of potassium and 237 +/- 55 mmol NaHCO3 were required. During the first 4 hours of the insulin infusion the blood sugar decrease per hour was 3.55 mmol/l (0.64 g/l). Hypokalaemia during treatment occurred in one case, hypoglycaemia was not observed. A preceding treatment with insulin and severe acidosis did not influence therapeutic success. Twelve patients were treated successfully, one patient died 6 hours after admission following mesenteric arterial embolism.

Adult

Reduced intraindividual variability of repeated cardiovascular reflex tests: an additional marker of autonomic neuropathy in insulin-dependent (type I) diabetes mellitus?

The particular questions asked in our study were: 1. does the individual reproducibility of the cardiovascular reflex tests differ between healthy controls and patients suffering from type I diabetes mellitus and 2. if there is a difference, do the different cardiovascular reflexes vary in this regard? Nine healthy controls (4 women, 5 men, age 31 +/- 2.1 years) and 11 type I diabetics (4 women, 7 men, age 30.9 +/- 5.6 years, duration of diabetes 3.23 years) underwent the following tests 6 times in a 12-h period (07:00 to 19:00): variation of heart rate during deep breathing (E/I ratio), variation of heart rate during lying and standing (tachycardia/bradycardia or 30/15 ratio), Valsalva maneuver (Valsalva ratio), response of diastolic blood pressure to sustained hand grip, and response of systolic blood pressure to posture. The test results did not indicate a diurnal fluctuation nor were they systematically influenced by antecedent insulin injections or meals, either in diabetic patients or in healthy controls. The 11 diabetics had significantly lower intraindividual variations of E/I and Valsalva ratios than the controls (p less than 0.05, p less than 0.001, respectively). In the diabetics with parasympathetic failure the intraindividual variabilities of all cardiovascular reflex responses were lower than those of the patients with an intact autonomic nervous system as well as those of the control subjects. On the contrary, in the diabetic patients without autonomic neuropathy, only the intraindividual variability of the Valsalva maneuver was significantly attenuated (p less than 0.025), compared with the healthy volunteers. To conclude, the more pathological the single test result, the greater is its reproducibility and its clinical significance.

Adult

Influence of cardiovascular diseases upon the results of the cardiovascular reflex tests in diabetic and nondiabetic subjects.

Cardiovascular reflex tests are used to assess cardiac autonomic neuropathy in diabetes mellitus. Cardiovascular diseases (CVD) are known to alter baroreflex mechanisms. Diabetic patients are at a high risk for cardiovascular complications. In order to prove whether cardiovascular diseases reduce the diagnostic value of the cardiovascular reflex tests in diabetic autonomic neuropathy unselected groups of 274 nondiabetic and 103 diabetic patients were studied: E/I, 30/15, and Valsalva ratios, sustained handgrip test and blood pressure response to standing. Both groups were subdivided into young (less than or equal to 45 years) and older (greater than 45 years) patients and into subjects with and without CVD. In young nondiabetic patients with CVD, E/I and Valsalva ratios were significantly lower than in those without CVD. In young diabetic patients with CVD, only E/I ratios were significantly reduced compared to those without CVD. The tests reflecting sympathetic nerve function did not differ between patients with and without CVD, neither in the nondiabetic nor in the diabetic subjects. In the older nondiabetic and diabetic patients, cardiovascular reflexes were generally impaired, but did not show any difference between subjects with and without CVD. In young diabetic patients suffering from CVD, the diagnostic value of cardiovascular reflex tests is reduced as far as cardiac autonomic neuropathy is concerned. In older patients, the tests are not suitable for the diagnosis of diabetic autonomic neuropathy. More specific methods are required.

Blood Pressure

Elevated muscle tissue oxygen tension in short-term insulin-dependent diabetes mellitus.

In order to assess hemodynamic changes in early phases of insulin-dependent diabetes mellitus, muscle tissue oxygen tensions were determined in 7 newly diagnosed insulin-dependent diabetic patients and in 6 healthy control subjects matched for sex, age and weight. Muscle tissue oxygen tension was measured by polarrographic needle probes while breathing ambient air and oxygen enriched air with an oxygen concentration of 40 per cent as well. Three times during the experiment, heart rates, blood pressures, blood glucose concentrations, and capillary oxygen tensions were obtained. Heart rate, blood pressure, peripheral and autonomic nerve functions did not differ between the 2 groups studied. While breathing ambient air, muscle tissue oxygen tensions were significantly (p = 0.025) higher in the diabetic patients than in the control subjects. In contrast to the control subjects, diabetic patients did not increase muscle tissue oxygen tensions after inhalation of oxygen enriched air despite of an equal increase in capillary oxygen tensions (2p less than 0.05). Local tissue hypoxia does not seem to be a leading cause of hemodynamic abnormalities in the early phases of diabetes.

Adult