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Biomedical subjects

C D Agardh

Publications and source records attributed to C D Agardh.

At least 109 records · Page 6Linked to original sources
PubMed1987

Platelet aggregation in type I diabetics with and without proliferative retinopathy.

The cause of retinopathy in diabetes mellitus is unknown. Among factors suggested to be involved in the development of retinopathy is altered platelet function. In the present study, platelet aggregation was measured in vitro after stimulation with adenosine diphosphate (ADP) and collagen in patients with and without proliferative retinopathy. The results show that patients with proliferative retinopathy have an increased platelet aggregation in vitro after stimulation with collagen and ADP. However, the increased platelet aggregation was also found to be correlated to the duration of diabetes. Thus, the present study does not support the opinion that abnormal platelet function can be regarded as a primary cause of diabetic retinopathy. Increased platelet aggregation seems to be coupled to the duration of diabetes and to still unknown factors developing with prolonged duration of the disease.

Adenosine Diphosphate↗
PubMed1987

Exercise stimulation in insulin-dependent diabetics, normal increase in albuminuria with abnormal blood pressure response.

Increased urinary albumin excretion rate (AER), microalbuminuria, has been regarded as a sign of incipient nephropathy. The influence of exercise on AER was investigated in 10 male type I diabetics and in 12 age-matched male controls. The duration of diabetes was 7-31 years (median 14 years). The exercise tests were performed both as a combined submaximal workload-waterload test and as a maximal workload test. Urinary albumin was measured with an ELISA technique. During exercise in both tests, no difference was seen in the AER between diabetics and their controls. However, the increase in systolic blood pressure was significantly more marked in the diabetics. There was no correlation between the blood pressure response during exercise and the AER, neither in the diabetics, nor in their controls. It is concluded, that, increased blood pressure response during exercise does not necessarily result in increased AER in type I diabetics.

Adult↗
PubMed1986

The influence of plasma insulin concentrations on tissue insulin levels in rodents: a study of the diabetic Chinese hamster and the ob/ob mouse.

Immunoreactive insulin was measured in acid-ethanol extracts of kidney, brain, liver, and heart from genetically diabetic Chinese hamsters and their nondiabetic controls and from obese (ob/ob) mice and their thin littermates. Selected samples were filtered on Sephadex G-50 columns and the insulin concentration determined. There was a good correlation between the insulin level measured in the acid-ethanol extracts of tissues and the insulin level after gel filtration, suggesting that the concentration measured in the whole extract is representative of the true insulin content. The present data demonstrate that different extrapancreatic organs contain characteristic amounts of insulin that are often (sometimes several-fold) higher than the insulin level of plasma. The tissue insulin concentrations also exhibit a wide range of values, with occasional high values. The data also show a direct correlation between plasma and kidney insulins but no relationship between plasma and brain insulins and a mixed correlation among plasma and liver and heart insulins.

Animals↗
PubMed1986

Influence of treatment with diethylstilbestrol for carcinoma of prostate on platelet aggregation and plasma lipoproteins.

Treatment of prostatic carcinoma with estrogens is accompanied by an increased risk for thromboembolic and cardiovascular complications. The underlying mechanisms are still unknown. Patients treated with diethylstilbestrol (DES) were compared with patients given no estrogen treatment regarding factors (platelet aggregation in vitro and plasma lipoproteins) that have been suggested to contribute to increased thrombogenesis and cardiovascular risk. The results do not show any increase in in vitro platelet aggregation in patients treated with DES compared with those given no treatment. This indicates that hyperaggregability does not contribute to the increased incidence in thromboembolic events seen in DES-treated patients. This is in contrast to the increased platelet aggregation previously described in patients treated with polyestradiolphosphate + etinylestradiol. The changes in plasma lipoproteins observed during DES-treatment are generally considered beneficial from an atherogenic point of view and do not appear to cause the elevated incidence of cardiovascular disease in these patients.

Aged↗
PubMed1986

Normal eyes in type 1 diabetics stay normal after one year of treatment with continuous subcutaneous insulin pump.

Seven patients with type 1 diabetes mellitus were restored to near normoglycaemia by treatment with continuous subcutaneous insulin infusion pumps (CSII). The patients were examined with ophthalmoscopy, fundus photography and fluorescein angiography before and one year after the start of CSII treatment. In addition, ophthalmoscopy was performed after 6 months of treatment. All 14 eyes were normal prior to the CSII treatment and none had developed any signs of retinopathy after 6 months or 1 year. It is concluded that metabolic control can be near normalized with CSII treatment without any risk for development of diabetic microangiopathy in type 1 diabetics with normal eyes.

Adult↗
PubMed1985

Lack of relation between glycosylated haemoglobin concentrations and number of daily insulin injections: cross sectional study in care of ambulatory diabetes.

Diabetic treatment aims at achieving a normal blood glucose concentration as reflected by the glycosylated haemoglobin concentration. Intensive treatment by insulin pump or multiple insulin injections is thought to achieve this. In an unselected group of outpatient diabetics metabolic control was the same after one, two, three, or more injections, which suggests that the mode of treatment was optimal for each group.

Ambulatory Care↗
PubMed1985

Diabetic control in community care. The use of clinical evaluation and hemoglobin A1.

Diabetic control was evaluated in 50 consecutive patients attending a community care centre, either by clinical criteria or by determination of glycosylated hemoglobin (HbA1). Two methods used for the determination of HbA1 were found to give similar results, namely ion exchange chromatography and agar gel electrophoresis. On a group basis, good correlation was observed between HbA1 samples analysed prior to and following the elimination of the labile HbA1 fraction. When comparing three treatment modes (diet alone, hypoglycemic agents or insulin), no significant differences in HbA1 levels were noted. Patients considered to have satisfactory and poor control had significantly higher HbA1 levels than those considered to have good control, while no differences were seen between those considered to have satisfactory or poor control. It is concluded that the methods described for the determination of HbA1 yield similar results. Clinical evaluation of diabetic control is reliable in patients classified to have good or poor control. However, in many patients who are considered to have satisfactory control, regular determinations of HbA1 provide valuable additional information.

Blood Glucose↗
PubMed1984

The influence of treatment with estrogens and estramustine phosphate on platelet aggregation and plasma lipoproteins in non-disseminated prostatic carcinoma.

The treatment of prostatic carcinoma with estrogens is associated with an increased risk of cardiovascular as well as thromboembolic complications. In the present study, patients harboring highly or moderately differentiated prostatic carcinoma without signs of metastases were treated with either polyestradiolphosphate + etinylestradiol, estramustine phosphate or given no treatment. Subsequently, these patients were investigated regarding factors (platelet aggregation, plasma and platelet phospholipid composition and lipoprotein patterns) that might contribute to increased thrombogenesis and cardiovascular risk. The results indicate the presence of increased in vitro platelet aggregation in patients treated with polyestradiolphosphate + etinylestradiol compared to those treated with estramustine phosphate or given no treatment. A possible relationship between the availability of arachidonic acid in platelet membrane phospholipids and in vitro platelet aggregation is suggested. On the other hand the alterations in plasma lipoproteins observed during treatment are generally considered positive from an atherogenic point of view and do not seem relevant to the elevated incidence of cardiovascular disease in these patients.

Aged↗
PubMed1984

Effect of dietary fibre on blood glucose, plasma immunoreactive insulin, C-peptide and GIP responses in non insulin dependent (type 2) diabetics and controls.

A high fibre and a low fibre breakfast meal were given to eight non insulin dependent diabetics ( NIDD ), and eight controls. Blood glucose response was monitored continuously for three hours and characterized using a straight line model. After the high fibre meal the rates of increase and decrease in blood glucose concentration were slower both in diabetics and controls than after the low fibre meal. The delay time, however, i.e. the time from meal intake to the start of glucose increase, hypothetically corresponding to gastric emptying time, was the same after both test meals. The postprandial glucose increment calculated as the area under the 0-120 min curve was lower after the high fibre meal in the NIDD , but not in the controls. The two-hour C-peptide and gastric inhibitory polypeptide values were lower for the diabetics after the high fibre breakfast. The results indicate a prolonged carbohydrate digestion and/or absorption after high fibre breakfast.

Adult↗
PubMed1984

Unique features of the insulin receptor in rat brain.

We examined the structure of the affinity-labeled insulin receptors in rat brain, rat liver, and human IM-9 lymphocytes using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In gels run under reducing conditions, the alpha-subunit of the insulin receptor in brain had an apparent Mr of 127,000 distinctly lower than that seen in both rat liver and human lymphocytes (apparent Mr = 136,000). Exposure to neuraminidase increased the electrophoretic mobility of the liver receptor, but had no effect on the insulin receptor in brain. The carbohydrate moieties of the insulin receptors in rat brain and liver were further examined by chromatography on wheat-germ agglutinin agarose. The receptors in both tissues adsorbed to the wheat-germ agglutinin; elution with 0.3 M N-acetyl glucosamine resulted in slightly better recovery of the brain than of the liver receptor. Exposure to neuraminidase virtually abolished the interaction of the liver receptor with the lectin, whereas adsorption of the brain receptor was unaffected by neuraminidase. These results indicate that the insulin receptor in brain is distinguished from those in peripheral tissues by structural alterations, including changes in the carbohydrate moiety of the receptor. Such alterations contrast sharply with the previously observed similarities in insulin binding properties between insulin receptors in brain and other tissues. The implications of such structural alterations for the program of insulin action expressed by the receptors in brain remain to be explored.

Affinity Labels↗
PubMed1983

Persistent vegetative state with high cerebral blood flow following profound hypoglycemia.

A persistent vegetative state (severe dementia) developed in a 30-year-old man following hypoglycemic coma. Despite the poor clinical outcome, sensory evoked response recovered between 6 and 34 months after the insult. The cerebral blood flow level at rest after 34 months was slightly above the normal range. This finding contrasts with the low cerebral blood flow regularly reported in patients who are comatose or stuporous following severe brain hypoxia-ischemia.

Adult↗
PubMed1983

Neurophysiological recovery after hypoglycemic coma in the rat: correlation with cerebral metabolism.

Recovery of electroencephalographic activity and somatosensory evoked responses was studied in paralyzed and lightly anesthetized (70% N2O) rats in which profound hypoglycemia had been induced by insulin administration. The duration of severe hypoglycemia was defined as the duration of a flat electroencephalogram (EEG) recording (5, 30, and 60 min, respectively) before restitution with glucose. The restitution period was followed by continuous EEG monitoring and repeated tests for evoked potentials. After 180 min of recovery, the brains were frozen in situ with liquid nitrogen and analyzed for energy metabolism. In accordance with earlier metabolic studies from this laboratory, the recovery after 60 min of severe hypoglycemia was incomplete, with signs of permanent failure of energy metabolism. There was persistent ATP reduction proportional to the duration of the hypoglycemia. The short-term recovery of EEG and sensory evoked responses was proportional to the duration of severe hypoglycemia. The neurophysiological recovery after 5 min of severe hypoglycemia was complete. After 30 min of severe hypoglycemia, the evoked responses recovered but showed a significant prolongation of latency, compared with normal. After 60 min of severe hypoglycemia, no early evoked response and scanty EEG activity were observed. The neurophysiological observations indicate a persistent deficit of synaptic transmission in the somatosensory pathway, including the cortical projection. This can be correlated with neuropathologic changes that are particularly prominent in intermediate cortical layers, as previously shown.

Animals↗
PubMed1983

Plasma high density lipoproteins and lipolytic enzyme activities in diabetic patients.

Eighty diabetic patients, consecutively selected from an out-patient clinic, were studied with regard to plasma lipoprotein levels, especially HDL. Patients treated with sulphonylureas had 24% lower HDL cholesterol concentrations (p less than 0.01) but only about 7% lower apo AI levels (n.s.) than those on insulin treatment. This difference could at least partly be explained by differences in age and type of diabetes. There was no relationship between the degree of diabetic control, as measured by fasting blood glucose levels, and HDL levels. In two subgroups of insulin-treated diabetics, selected to represent extremely low and high HDL levels (range 0.5-0.8 and 1.8-2.0 mmol/l, respectively) but matched with regard to age, duration of diabetes, insulin dosage and diabetic control, the activities of lipoprotein lipase and hepatic lipase in postheparin plasma were also recorded. The high HDL group had significantly higher lipoprotein lipase activities (p less than 0.01) and significantly lower hepatic lipase activities (p less than 0.05) than the low HDL group, supporting the hypothetical roles of these enzymes in HDL metabolism, and offering a tentative mechanism behind the large variability of HDL levels in diabetics.

Adolescent↗
PubMed1983

Improvement of peripheral nerve function after institution of insulin treatment in diabetes mellitus. A case-control study.

The influence of improved diabetic control on peripheral nerve function was studied before and 3-4 months after institution of insulin treatment in 22 diabetics unsatisfactorily controlled by oral hypoglycemic agents. After institution of insulin treatment, diabetic control was improved as demonstrated by decreasing levels of HbA1. There was an overall tendency towards improvement of motor and sensory conduction velocities, however significant only in the upper extremities. There was a tendency towards improved temperature sensitivity in the legs, while no changes occurred in the hands and face. The sensation for vibration did not change. It is concluded that improved diabetic control, even in elderly patients with long-standing diabetes, is followed by neurophysiological signs of improved peripheral nerve function.

Adolescent↗
PubMed1983

The influence of total hepatectomy on cerebral energy state, ammonia-related amino acids of the brain and plasma amino acids in the rat.

The influence of total hepatectomy on cerebral energy state, ammonia-related amino acids of the brain tissue and plasma amino acids was studied in anaesthetized rats after total hepatectomy. The hepatectomy was performed with the aid of a microsurgical three-stage procedure. In the first stage, division of the inferior vena cava was performed. In the second stage 4 weeks later a porta-caval anastomosis was constructed, followed after 1 week by a total hepatectomy. The brain energy state, defined as the concentrations of phosphocreatine, ATP, ADP and AMP, was unchanged 4 h after the hepatectomy. Plasma amino acids did not differ significantly between hepatectomized and shunted control rats. On the other hand, clear-cut increases in the concentrations of glutamine, and decreases in the concentrations of glutamate and aspartate, were observed in the fronto-parietal part of the cerebral cortex and the brain stem. These changes might explain the minor manifestations of cerebral dysfunction in the early phase of the hepatectomized state.

Alanine↗
PubMed1983

Desensitisation as a means of preventing untoward reactions to ionic contrast media.

Patients with a previous history of anaphylactic reactions to ionic iodinated contrast media were desensitised before a second radiologic examination was performed. The tolerance to the contrast medium was raised by repeated intravenous injections in increasing doses and concentrations. No serious side effects were noted when the examinations with contrast medium was repeated within a few days after the desensitisation. The positive effect of the desensitisation may depend on a successive consumption of complement proteins, probably responsible for the allergic reactions. Therefore, the available amount of complement for some days may be too low for the occurrence of a complement reaction.

Adult↗
PubMed1982

Serum beta-hexosaminidase in diabetes mellitus with reference to the type of treatment.

A significantly increased serum level of beta-hexosaminidase was found in an unselected group of 85 diabetics. When the patients were divided into three groups according to type of treatment, increased enzyme levels were found only in patients treated with oral hypoglycemic agents or diet while insulin-treated patients had normal serum levels of beta-hexosaminidase. There was a positive correlation between beta-hexosaminidase and blood glucose concentration for the entire patient series. When grouped according to treatment, a positive correlation was found only in the insulin-treated group despite its normal serum activity of beta-hexosaminidase. Serum beta-hexosaminidase of patients with retinopathy did not differ from the mean value of their group. It is concluded that the activity of beta-hexosaminidase in diabetics can produce different results depending on the type of patients under study.

Adolescent↗