[The dental technician project 1982-1983].
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Dental Technicians↗
Biomedical subjects
B Persson
Publications and source records attributed to B Persson.
The effect of total body microwave hyperthermia and hepatic artery ligation on liver tumors--an experimental study in rats.
The effect of general microwave hyperthermia and hepatic artery ligation (HAL) was tested on Wistar rats with a transplanted N-methyl-N-nitrosoguanidine-induced adenocarcinoma in the liver. Total body hyperthermia (41.5 degrees C for 1 hour, three times during 24 hours) was given on the same day as HAL, and 1, 2, and 3 days after. HAL induced a slower tumor growth than untreated controls. No additive effect was registered when total body microwave hyperthermia was added to HAL. When hyperthermia was added 2 days after HAL, there was a transient decrease in tumor volume as in the HAL series. Total body microwave hyperthermia added 3 days after HAL induced a faster tumor growth than after HAL alone. When hyperthermia was added the same day and 1 day after HAL, there was a 50% mortality.
Animals↗
Ketanserin in essential hypertension: effects during rest and exercise.
Ketanserin is a new, specific serotonin receptor blocking agent, which causes vasodilatation, presumably by an action on the vascular wall. The antihypertensive response to ketanserin 40 mg twice daily as monotherapy was assessed in 8 patients with essential hypertension. The investigation was an 8 week, double-blind, cross over study, which also included measurements during isometric (handgrip) and dynamic exercise (bicycle ergometry), as well as determination of plasma catecholamines and ketanserin. Ketanserin caused a reduction of supine and standing systolic and diastolic blood pressure (BP) during rest and a slight bradycardia. Although there was attenuation of the pressor response to handgrip, treatment with ketanserin did not really affect the changes in BP or heart rate during exercise, i.e. the base-line differences remained the same. There was no significant correlation between the effect on BP and the plasma level of ketanserin. The changes in BP produced by ketanserin showed little correlation with the initial levels of plasma catecholamines or with alterations in those levels. Although the results did not indicate direct interference by ketanserin with sympathetic tone, the lack of reflexogenic tachycardia, as well as the lack of increase in plasma noradrenaline during hand grip, indicates at least some modulation of autonomic function. It is concluded that ketanserin lowers BP in essential hypertension without interference with cardiovascular reflexes during standing or exercise, and that the compound may offer an alternative approach in the treatment of hypertension.
Antihypertensive Agents↗
Amino acid sequence restriction in relation to proteolysis.
Distributions of amino acid residues in proteins show that proline is overrepresented in sequence positions following two basic residues ([Lys Arg]-[Lys Arg]), i.e. at sites similar to those susceptible to proteolytic cleavages of hormonal pro-forms. Conformational correlations further show that [Lys Arg]-[Lys Arg]-Pro sequences are often (8/11) not adjacent to elements of secondary structure, whereas the opposite applies to [Lys Arg]-[Lys Arg]-nonPro sequences (82/103 adjacent to elements of secondary structure). These distribution patterns from proteins in general also seem applicable in individual protein groups as demonstrated for some dehydrogenases. It appears possible that [Lys Arg]-[Lys Arg]-nonPro constitutes a restricted sequence in proteins, and that proline, in addition to elements of secondary structure, contributes a means of avoiding unacceptable proteolytic processings of proteins in general.
Amino Acid Sequence↗
Ketanserin, a novel 5-hydroxytryptamine antagonist: monotherapy in essential hypertension.
Blood pressure and heart rate, supine and standing, were studied in patients with essential hypertension during 8 weeks of oral therapy with two dosage schedules of ketanserin, 40 mg once and twice daily. Ketanserin caused significant reductions in both supine and standing blood pressure but no significant alterations in heart rate in both groups of patients. Measurements of blood pressure and heart rate over a 24 h period during steady state conditions revealed that maximal blood pressure reduction was correlated with time to peak plasma concentrations. Steady state plasma concentrations of ketanserin were significantly higher in the patients receiving 40 mg twice daily compared to 40 mg once daily. In the group with once daily treatment, tmax was 1.2 +/- 0.17 h, Css 13 +/- 4.3 ng/ml, Cmax 137 +/- 19.6 ng/ml and t1/2, z h. 9.6 +/- 1.27 h.
Adult↗
Rehydration using solutions with and without glucose before emergency abdominal surgery in children.
The metabolic effects of six different solutions used for rehydration were studied in 88 children before emergency abdominal surgery. A volume corresponding to 5% of the body weight was given i.v. during 4 h (12.5 ml . kg-1 . h-1) between admission and surgery. The different solutions were: low glucose electrolyte solution (LGE), Rehydrex 2.5%, Rehydrex 5% containing 0.9, 2.5 and 5.0% glucose, respectively, Ringer, Ringer lactate and Ringerdex (30 mmol acetate . l-1). Venous blood samples were drawn before and after rehydration and analysed for glucose, insulin, alanine, 3-hydroxybutyrate (3-HB), non-esterified fatty acids (NEFA), glycerol and base excess. Before rehydration the plasma concentrations of NEFA, glycerol and 3-HB were elevated, while that of alanine was decreased. Plasma levels of NEFA and 3-HB remained unchanged, whereas glucose and insulin decreased after rehydration with glucose-free solutions, i.e. Ringer, Ringer lactate and Ringerdex. With solutions containing glucose the concentrations of NEFA and 3-HB decreased significantly. With Rehydrex 5% hyperglycaemia and hyperinsulinaemia were observed. Rehydration using LGE and especially Rehydrex 2.5% resulted in decreased lipid mobilization and ketonaemia without concomitant marked increase of glucose and insulin. LGE and Rehydrex 2.5% thus appeared to be the most appropriate solutions in a situation where moderate dehydration had to be corrected during a short period of time before emergency abdominal surgery.
Abdomen, Acute↗
Effect of metabolic control and duration on exercise-induced albuminuria in diabetic teen-agers.
Nineteen type I diabetic teen-agers without clinical signs of nephropathy with a duration of diabetes varying from 3 to 16.8 years were examined by a standardized exercise test for analysis of urinary excretion of albumin and beta 2-microglobulin. The patients were studied both in poor and improved (but not perfect), metabolic control as defined by HbA1c and blood glucose profiles, and the values were compared to those of 14 age-matched healthy controls. The controls showed no increase in albumin excretion rate during exercise as was found in diabetic patients. The albumin excretion rate during exercise was significantly correlated (p less than 0.05) to systolic blood pressure in the diabetic patients. Blood pressure in the diabetic patients was, however, similar to that of controls both at rest and during exercise. Urinary beta 2-microglobulin did not change during exercise. The urinary albumin excretion during exercise decreased significantly with improved metabolic control in diabetic patients, but the albumin excretion rate was not correlated with either blood or urinary glucose or diuresis during the exercise test. When metabolic control was improved there was a significant correlation between the increase in albumin excretion rate during exercise and the duration of diabetes, indicating that part of the exercise-induced albumin excretion might reflect irreversible morphological changes in the diabetic kidney. This test might therefore have a predictive value for diabetic nephropathy if performed during strict metabolic control.
Adolescent↗
Renal function in relation to metabolic control in children with diabetes of different duration.
To evaluate the interpretation of different kidney function tests in diabetic children and teenagers we have studied 47 children with a duration of diabetes up to 5 years, 61 children with a duration of 5.1-10 years and 49 children with a duration of greater than 10 years. Glomerular filtration rate (GFR) measured as inulin clearance or creatinine clearance, clearance PAH (CPAH), filtration fraction (FF), 24-hour urinary excretion of beta 2-microglobulin and albumin were examined and correlated with short- and longterm indices of metabolic control. In all groups of duration GFR as measured by inulin clearance was increased compared with reference values from age matched controls. In patients who had had diabetes for 0-5 years a significant positive correlation was found between inulin clearance and blood glucose during the examination. Inulin clearance was also correlated to HBA1c as well as to 24-hour urinary glucose (mean of 4-6 samples during two years). No such correlation was found in the group who had had diabetes for 5-10 years but in patients with a duration of diabetes greater than 10 years a significant inverse relation was found between GFR and HbA1c. The 24-hour urinary excretion of albumin was significantly higher in all groups of diabetics compared with controls. The urinary excretion of beta 2-microglobulin was similar in diabetics and controls. In the total material no significant correlation could be found between inulin clearance and creatinine clearance.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
An appraisal of techniques for studying cerebral circulation in the newborn. Report of a mini-symposium held in September 1982.
The study of cerebral circulation in ill pre-term infants is important both to improve our understanding of the physiological aspects of cerebral blood flow control, and to provide further insight into the aetiology of intracranial intra-ventricular haemorrhage. Progress in this field has been hampered by the absence of measurement techniques which must be safe and clinically applicable whilst at the same time providing results with sufficient quality for the confident development of hypotheses. The symposium was held in order to evaluate critically the measurement techniques which might be considered for use in the sick, human newborn infant.
Cerebrovascular Circulation↗
Cardiovascular effects of THIP in the rat.
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Animals↗
Monoclonal antibodies against gastrointestinal tumour-associated antigens isolated as monosialogangliosides.
Monoclonal antibodies were produced after immunization of mice with a colorectal adenocarcinoma cell line or liver metastasis membranes from a patient with colon adenocarcinoma. Many monoclonal antibodies were found to react with colorectal adenocarcinoma cells but not with normal colon mucosa, blood lymphocytes, myeloma cells or lung epithelial carcinoma cells. Three of these 'colorectal tumour-specific' antibodies appear to define different antigens that were found in the complex monosialoganglioside fraction from 60 to 90% of the colorectal and pancreatic adenocarcinoma tumours or metastases examined but essentially lacking in normal colon mucosa and other normal or tumour tissues tested.
Adenocarcinoma↗
Insulin-induced hypoglycemia in pregnant diabetics. Maternal and fetal cardiovascular reactions.
Insulin (0.1 IU/kg bw) was injected intravenously in 9 pregnant diabetics in the last trimester of pregnancy. Maternal levels of blood glucose, estriol, human placental lactogen, blood pressure and pulse rate were measured and fetal heart rate (FHR) recorded. During hypoglycemia maternal blood pressure remained unchanged but maternal pulse rate tended to increase. Plasma levels of estriol and HPL remained unchanged. In 6 of the 9 patients there was a decrease in FHR variability during the hypoglycemic period. FHR variability increased after normalization of maternal blood glucose levels. The decrease in FHR variability could be a direct effect of glucopenia on the fetal heart.
Adult↗
Percutaneous transluminal angioplasty (PTA) for lower extremity arterial insufficiency.
Short term results of treatment with percutaneous transluminal angioplasty (PTA) for lower extremity arterial insufficiency are presented. During a two year period 54 PTA were attempted and 43 were successful. 42 patients were either free of symptoms or had objectively reduced ischemic symptoms and remained so during the follow-up period (mean 10.5 months). Successfully repeated PTA were performed in three patients for the management of occlusions within an arterial segment earlier dilatated. Reasons for unsuccessful PTA were mainly difficulties in passing the stenosis/occlusion with the guide wire or that dilation could not be completed because of extensive calcification in the arterial wall. The only complication requiring treatment was a bleeding from a puncture site in the femoral artery. PTA treatment of lower extremity arterial insufficiency is for many patients a good alternative or complement to reconstructive vascular surgery and a method that should be used to a greater extent in vascular surgery centers.
Aged↗
Liver blood flow studies during local hyperthermia. An experimental study in rats.
Regional blood flow in rat liver and in inoculated liver tumors was studied before, during and after local hyperthermia treatment at 42.0 degrees C for one hour. Hyperthermia was induced by microwave irradiation of the central liver lobe. The method used for blood flow studies was the clearance of Xenon-133 following portal and intraparenchymal injection. The wash-out curves were analyzed by using a bi-exponential approach where k1 and k2 represented the individual curve slope of the two components. The fast component, k1, was considered to denote the relative liver blood flow. There was no difference in blood flow (k1) between tumor and normal parenchyma before heating. During local hyperthermia of the liver lobe an overall statistically significant decrease in relative blood flow occurred. In normal liver parenchyma a statistically significant increase in blood flow occurred within 30 min after concluded hyperthermia with a return to prehyperthermic values. Intratumoral blood flow did not increase in the posthyperthermic period. The decrease in relative blood flow in the liver parenchyma during hyperthermia may be one explanation for liver sensitivity to hyperthermia treatment. Local hyperthermia may impair the tumor capillary network with a decreased blood flow and alteration in the intratumoral environment as a result.
Animals↗
Measurement of blood flow in rat liver with Xenon-133.
The blood flow in rat liver was measured with Xe-133. Three techniques for administering the activity to the liver were employed: injection via the portal vein, via the hepatic artery, and directly into the liver parenchyma. Use of intraparenchymal injection of Xe-133 gave 60% higher flow values than by portal or arterial injection techniques. Mean flow index (k1) was for portal injection 0.52, for arterial injection 0.51 and for intraparenchymal injection 0.80. These variations may be explained by the microcirculatory anatomy of the rat liver. The data presented have a high degree of variance between repeated experiments on the same animal. During an experimental procedure, only larger changes in the liver blood flow pattern can be detected with sufficient accuracy. For this purpose, the method is applicable since repeated and regional studies on the same organ can easily be performed.
Animals↗
Colorectal carcinomas have a characteristic ganglioside pattern.
The gangliosides in six colorectal and two pancreatic carcinomas were examined. Their concentration in the primary tumour and the metastases was 5-10 fold higher than in normal colon mucosa. This increase involved the simple gangliosides, GM3 and GD3, as well as complex mono- and disialogangliosides. Some complex monosialogangliosides were detected in all the colorectal and pancreatic carcinomas but neither in normal colon mucosa and pancreas nor in kidney and lung carcinomas.
Aged↗
Fetal beta cell function in diabetic pregnancy. Amniotic fluid concentrations of proinsulin, insulin, and C-peptide during the last trimester of pregnancy.
Proinsulin, insulin C-peptide, insulin-binding antibody, and glucose concentrations were measured in amniotic fluid samples from 43 insulin-treated diabetic patients and 17 nondiabetic control patients between the thirty-six and thirty-ninth weeks of gestation. Insulin-binding antibodies in amniotic fluid were present in only three diabetic patients, although antibodies in maternal serum were found in 22 of the diabetic subjects. In the diabetic group, maternal serum insulin-binding antibodies were statistically unrelated to levels of C-peptide in amniotic fluid. The mean amniotic fluid concentrations of proinsulin (0.07 nmole/L), insulin (0.08 nmole/L), C-peptide (1.17 nmoles/L), and glucose (2.09 mmoles/L) were markedly elevated (p less than 0.001) in diabetic patients, as compared to nondiabetic control patients, thus suggesting exaggerated fetal beta cell function. C-peptide was correlated to both insulin (r = 0.69) and proinsulin (r = 0.35) in the diabetic group only. Infant birth weight and amniotic fluid C-peptide was significantly correlated in both the control group (r = 0.54) and the diabetic group (r = 0.38). Diabetic pregnancies associated with neonatal morbidity (n = 25) had significantly higher mean amniotic fluid concentrations of both insulin and C-peptide than did pregnancies without neonatal morbidity (n = 18). The amniotic fluid values of C-peptide and insulin in these latter two subgroups were overlapping and, therefore, could not serve to predict neonatal outcome in the individual case.
Adult↗