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Biomedical subjects

A R Andersen

Publications and source records attributed to A R Andersen.

At least 73 records · Page 4Linked to original sources
PubMed1985

Converting enzyme inhibition resets cerebral autoregulation at lower blood pressure.

The cerebrovascular effect of converting enzyme inhibition was investigated in normal volunteers, in hypertensive patients and in patients with severe chronic heart failure. Cerebral blood flow (CBF) was measured by single photon emission tomography of the uptake and wash-out of inhaled xenon-133. In some of the patients, CBF was also monitored by repeated determinations of the cerebral arterio-venous oxygen difference. In the normal volunteers and the hypertensive patients captopril (50 mg) caused a downward shift of the lower limit of CBF autoregulation of 10-15 mmHg. In some of the patients with chronic heart failure, captopril (6.25 mg) induced a marked decrease of the arterial blood pressure. Regional and average CBF, however, remained constant. These findings indicate that captopril treatment may protect the brain against ischaemia during sudden decreases of the blood pressure by a shift of the lower limit of CBF autoregulation.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1985

Dynamic SPECT of the brain using a lipophilic technetium-99m complex, PnAO.

The lipophilic 99mTc-labeled oxime propylene amine oxime (PnAO) should, according to recent reports behave like 133Xe in the human brain. This study compares SPECT images of the two tracers in six subjects: four stroke cases, one transitory ischemic attack case and one normal subject. Technetium-99m PnAO was injected i.v. as a bolus of 15 to 25 mCi. The distribution was followed over 10-sec intervals using a highly sensitive, rapidly rotating SPECT (Tomomatic 64) and compared to 133Xe flow maps. Upon arrival of the PnAO bolus to the brain, a high uptake was found in brain tissue with high cerebral blood flow followed by rapid washout. In the stroke cases, low flow areas were equally well visualized by both tracers. Two dissimilarities were seen in the initial pictures: PnAO visualized the cerebral veins and showed a lesser contrast of gray:white matter uptake. The results suggest that PnAO has a high yet incomplete brain extraction yielding a flow dominated initial distribution with limitations mentioned.

Adult↗
PubMed1984

Renal changes in long-term type 1 (insulin-dependent) diabetic patients with and without clinical nephropathy: a light microscopic, morphometric study of autopsy material.

The relationship between clinical diabetic nephropathy and morphological renal changes was studied in autopsy material from 34 long-term Type 1 (insulin-dependent) diabetic patients of juvenile onset. Seventeen had no clinical signs of nephropathy (defined by persistent proteinuria, hypertension, and elevated serum creatinine) while a further 17 age-matched diabetic patients with a similar duration of diabetes had severe clinical nephropathy. The renal tissue was examined by morphometric light microscopy, using a point counting technique and the results compared with renal tissue from subjects who died without diabetes. In the diabetic patients without clinical nephropathy, arteriolohyalinosis was much more pronounced compared with non-diabetic subjects (2p less than 0.001) and within the glomeruli the amount of subcapsular fibrosis and glomerular mesangium was increased (2p less than 0.05 and less than 0.001, respectively). The area of open capillaries was decreased compared with non-diabetic subjects (2p less than 0.025), and the percentage of occluded glomeruli was significantly increased (2p less than 0.05). The diabetic patients with clinical nephropathy had significantly more interstitial tissue and glomerular mesangium (2p less than 0.001) and less open glomerular capillaries (2p less than 0.001) than diabetic subjects without clinical nephropathy, but severe glomerulosclerosis could be seen in the diabetic patients without any sign of clinical nephropathy. Serum creatinine correlated with the mesangial area (r = 0.792, 2 a less than 0.001). No difference was observed between the two diabetic groups regarding the degree of arteriolohyalinosis, the number of Kimmelstiel-Wilson lesions or exudative lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Impaired autoregulation of glomerular filtration rate in type 1 (insulin-dependent) diabetic patients with nephropathy.

The effect of acute lowering of arterial blood pressure upon kidney function in nephropathy was studied in 13 patients with long-term Type 1 (insulin-dependent) diabetes. Ten normal subjects (six normotensive and four hypertensive) and five short-term Type 1 diabetic patients without nephropathy served as controls. Renal function was assessed by glomerular filtration rate (single bolus 51Cr-EDTA technique) and urinary albumin excretion rate (radial immunodiffusion). The study was performed twice within 2 weeks, with the subjects receiving an intravenous injection of either clonidine (225 micrograms) or saline (0.154 mmol/l). The arterial blood pressure was similar in the diabetic patients with nephropathy (mean 136 +/- 11 divided by 88 +/- mmHg) and in the non-diabetic control subjects (mean 140 +/- 25 divided by 92 +/- 15 mmHg). The clonidine injection induced similar reductions in mean arterial blood pressure in all three groups (16-18 mmHg). While glomerular filtration rate and urinary albumin excretion rate remained unchanged in both control groups after clonidine injection, glomerular filtration rate diminished from 78 to 71 ml/min per 1.73 m2 (p les than 0.01), and urinary albumin excretion declined from 1707 to 938 micrograms/min (p less than 0.01) in the patients with diabetic nephropathy. Our results suggest that an intrinsic vascular (arteriolar) mechanism underlying the normal autoregulation of glomerular filtration rate, i.e. the relative constancy of glomerular filtration rate that occurs in response to rather wide variations in perfusion pressure, is defective in diabetic nephropathy.

Adult↗
PubMed1984

Smoking habits and prevalence of clinical diabetic microangiopathy in insulin-dependent diabetics.

All patients having insulin-dependent diabetes with onset before 30 years of age and a duration of disease of 12-40 years who visited a diabetes centre within one year were registered. 97% (n = 668) answered a WHO questionnaire on cigarette smoking. The smoking habits were compared to the frequency of proliferative retinopathy and/or diabetic nephropathy (persistent proteinuria). The prevalence of diabetic nephropathy was significantly higher among heavy smokers (greater than 10 cigarettes a day for more than one year) than among non-heavy smokers, 19.2% versus 12.1% (p less than 0.02). An increasing frequency of nephropathy was found with increasing cigarette consumption (p less than 0.01). No difference in the prevalence of proliferative retinopathy was found between smokers and non-smokers. It is concluded that cigarette smoking is a risk factor for the development of nephropathy in insulin-dependent diabetics.

Adult↗
PubMed1984

[Necrobiosis lipoidica in a patient with bronze diabetes].

A case of necrobiosis lipoidica in a patient with idiopathic hemochromatosis and diabetes mellitus is presented. Histologic examination revealed excessive amounts of iron pigment in macrophages in the corium of the necrobiotic skin. There were no iron deposits in the normal skin.

Diabetes Mellitus, Type 1↗
PubMed1983

Early aggressive antihypertensive treatment reduces rate of decline in kidney function in diabetic nephropathy.

The effect of early aggressive antihypertensive treatment on kidney function in diabetic nephropathy was studied prospectively in ten insulin-dependent diabetics (mean age 29 years). During the mean pretreatment period of 29 (range 23-38) months the glomerular filtration rate (GFR) decreased significantly and the urinary albumin excretion rate and arterial blood pressure rose significantly. During the 39 month (range 28-48) period of antihypertensive treatment with metoprolol, hydralazine, and frusemide (furosemide) or thiazide, arterial blood pressure fell from 144/97 mm Hg (mean of all pretreatment values) to 128/84 mm Hg (mean of all post-treatment values), urinary albumin excretion from 977 micrograms/min to 433 micrograms/min, and GFR from 80 to 62 ml/min/1 . 73 m2. The rate of decline in GFR decreased from 0.91 ml/min/month before treatment to 0.39 ml/min/month (range 0.08 to 0.68 ml/min/month) during treatment.

Adult↗
PubMed1983

Diabetic nephropathy and arterial hypertension.

The relationship between arterial blood pressure and diabetic nephropathy was examined in 61 Type 1 (insulin-dependent) diabetic patients (22 females and 39 males). All patients fulfilled the following criteria: persistent proteinuria (greater than 0.5 g/day), onset of diabetes before 31 years of age, age less than 42 years, serum creatinine less than 130 mumol/l, and no antihypertensive treatment. Thirty Type 1 diabetic patients without persistent proteinuria but matched for sex, age, ideal body weight and duration of diabetes, and 30 healthy subjects matched for sex, age and ideal body weight were also studied as controls. The diabetic patients with persistent proteinuria had elevated blood pressures (146/96 +/- 17/10 mmHg, mean +/- SD) compared with 123/75 +/- 11/8 mmHg in diabetic patients without persistent proteinuria, and normal subjects (120/77 +/- 6/6 mmHg; p less than 0.001 for each). Diastolic blood pressure greater than or equal to 95 mmHg was found in 51% of the group with persistent proteinuria. Elevated arterial blood pressure is frequently present in young Type 1 diabetic patients with diabetic nephropathy and normal serum creatinine.

Adult↗
PubMed1983

Diabetic nephropathy in Type 1 (insulin-dependent) diabetes: an epidemiological study.

A follow-up of 1475 Type 1 (insulin-dependent) diabetic patients diagnosed before 1953 (815 males, 660 females) and before the age of 31 years was conducted. All patients were seen at the Steno Memorial Hospital and were referred from all parts of Denmark; 91 (6%) could not be traced. The rest (94%) were followed until death or for at least 25 years; 249 (17%) were followed for greater than 40 years. Clinical diabetic nephropathy developed in 531 (41%) of the 1303 patients in whom sufficient information was available regarding proteinuria. Other causes of proteinuria were found in 3%, and 57% did not develop persistent proteinuria. The prevalence of diabetic nephropathy was 21% after 20-25 years of diabetes duration followed by a decline to 10% after 40 years. Two incidence peaks of the onset of proteinuria were seen, one after 16 and another after 32 years duration of diabetes and was low after 35 years duration. The cumulative incidence was 45% after 40 years of diabetes. A male preponderance was seen among patients with nephropathy. A significant difference in the pattern of annual incidence rates of diabetic nephropathy was seen, when groups with onset of diabetes before 1933, between 1933-1942, and 1943-1952, respectively, were compared. An association between daily insulin requirement and nephropathy incidence was found. Patients with nephropathy had a much poorer survival than those without proteinuria; 40 years after onset of diabetes, only 10% of patients who developed nephropathy were alive, whereas greater than 70% of patients who did not develop nephropathy survived.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1983

Diabetic nephropathy and arterial hypertension. The effect of antihypertensive treatment.

Our longitudinal study of urinary albumin excretion rate in long-term insulin-dependent diabetics without proteinuria (negative albustix) suggests that early detection of patients at high and low risk of developing persistent proteinuria, i.e., diabetic nephropathy, is possible by using a sensitive method for albumin determination. Our prospective studies in young insulin-dependent diabetics with diabetic nephropathy show that the rate of decline in glomerular filtration rate (GFR) varies considerably, with a mean of 0.75 ml/min/mo and a range from 0.1 to 1.50 ml/min/mo, and that an increase in arterial blood pressure to a hypertensive level is an early feature; 43% of the patients had diastolic blood pressure greater than 100 mm Hg. Early and aggressive antihypertensive treatment reduces both albuminuria and the rate of decline in GFR in young patients with diabetic nephropathy.

Adult↗
PubMed1981

A prospective study of glomerular filtration rate and arterial blood pressure in insulin-dependent diabetics with diabetic nephropathy.

Glomerular filtration rate (GFR, single bolus 51Cr-EDTA technique), serum creatinine, proteinuria and arterial blood pressure have been measured prospectively in 14 young onset insulin-dependent diabetics selected by of persistent proteinuria (greater than 0.5 g/day) secondary to diabetic nephropathy. Twelve of the 14 patients had normal serum creatinine levels. None of the patients received antihypertensive treatment. During the mean observation period of 26 months (range 23 to 33 months) GFR decreased from 107 to 87 ml/min/1.73 m2 (p less than 0.001), serum creatinine remained unchanged: 107 and 112/mumol/l (NS), proteinuria increased from 1.8 to 3.3 g/day (p less than 0.001) and arterial blood pressure rose from 132/88 to 153/101 mmHg (p less than 0.001). Glomerular filtration rate decreased linearly with time (slope = -0.75, r = 0.99, p less than 0.001) by a mean of 0.75 ml/min/month (range 0.1 to 1.5 ml/min/month). The decrease in GFR did not correlate wih sex, age at onset, duration of diabetes, arterial blood pressure, proteinuria, insulin requirement, postprandial blood glucose or the initial GFR in each individual was constant, but varied considerably between patients. Increase in arterial blood pressure to a hypertensive level is an early feature of diabetic nephropathy in young insulin-dependent diabetics.

Adult↗
PubMed1981

Kidney function and size in normal subjects before and during growth hormone administration for one week.

Kidney function and size were studied in seven normal male subjects before and after administration of highly purified human growth hormone for 1 week. Glomerular filtration rate, renal plasma flow (steady-state infusion technique with urinary collections using 125I-iothalamate and 131I-hippuran) kidney size (ultrasonic scanning) and urinary excretion rates of albumin and beta 2-microglobulin (radioimmunoassays) were measured. Highly purified growth hormone was injected subcutaneously, 2 IU in the morning and 4 IU in the evening. Glomerular filtration rate increased from (mean +/- SEM) 114 +/- 5 to 125 +/- 4 ml/min x 1.73 m2 (P less than 0.01) and renal plasma flow increased from 554 +/- 30 to 601 +/- 36 ml/min x 1.73 m2 (P less than 0.01). Kidney size and urinary excretion rates of albumin and beta 2-microglobulin did not change significantly. Our results show that raising plasma growth hormone into a range similar to that found in insulin-dependent diabetics enhances glomerular filtration rate and renal plasma flow, while kidney size remains unchanged. Increased renal plasma flow is the major determinant of growth hormone induced elevation in glomerular filtration rate. Growth hormone may thus contribute to the enhancement of glomerular filtration rate and renal plasma flow typically found in insulin-dependent diabetics.

Adult↗