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Biomedical subjects

H H Parving

Publications and source records attributed to H H Parving.

At least 19 recordsLinked to original sources
PubMed1992

Renoprotective action of angiotensin-converting enzyme inhibition in diabetes mellitus.

Roughly 40% of all diabetics, whether insulin dependent or not, develop persistent albuminuria, a decline in their glomerular filtration rate, and elevated blood pressure, i.e., diabetic nephropathy. Diabetic nephropathy is the single most important cause of end-stage renal disease in the Western world, accounting for over one-quarter of all end-stage renal disease. Systemic/glomerular hypertension plays a role in the initiation and progression of diabetic glomerulopathy. Angiotensin-converting enzyme (ACE) inhibitors are superior to conventional antihypertensive drugs in preventing the development of glomerular lesions in insulin-treated streptozotocin diabetic rats. Lowering of glomerular hypertension may be the crucial factor involved. Human studies suggest that ACE inhibitors postpone the progression to clinical overt diabetic nephropathy in normotensive diabetic patients with persistent microalbuminuria. ACE inhibitors combined with a diuretic reduce albuminuria and postpone renal insufficiency in hypertensive diabetics with overt nephropathy. No treatment modality other than antihypertensive treatment has yet been proven to be effective in protecting renal function in diabetic nephropathy. All previous reports dealing with the natural history of diabetic nephropathy have demonstrated a cumulative death rate between 50 and 77% 10 years after the onset of proteinuria. Effective antihypertensive treatment has reduced the cumulative death rate to 15-20% 10 years after the onset of nephropathy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1979

Mechanisms of edema formation in myxedema--increased protein extravasation and relatively slow lymphatic drainage.

We assessed extravascular accumulation of albumin and fluid in primary myxedema by measuring metabolic turnover and transcapillary escape of 131I-labeled human albumin in seven patients. In the hypothyroid state, we found a low plasma volume (P less than 0.05), a reduced rate of albumin synthesis and catabolism (P less than 0.01), an increased transcapillary escape rate of albumin (P less than 0.01), a remarkable increase in the extravascular mass of albumin (1500 micronmol; P less than 0.01) and a longer mean transit time through the extravascular spaces in primary myxedema than in other states of generalized edema (P less than 0.05). All variables returned to normal during l-thyroxine treatment. The extravascular accumulation of albumin, and presumably of all other plasma proteins, is important in the generalized edema typically found in myxedema. Inadequate lymphatic drainage may also explain the formation of exudates in the serous cavities that are well known in myxedema.

Adult↗
PubMed1979

Effect of metabolic regulation on renal leakiness to dextran molecules in short-term insulin-dependent diabetics.

Renal clearance of dextran of two ranges of molecular size and glomerular filtration rate (GFR, 51Cr-EDTA) were measured in seven short-term insulin-dependent diabetics (mean age 25 years). Measurements were carried out in the same patient during good and poor metabolic regulation (plasma glucose, mean +/- SEM, 6.5 +/- 0.9 and 14.8 +/- 1.5 mmol/l, respectively). GFR was elevated in all patients during poor metabolic regulation (119 +/- 6 ml/min/1.73 m2, versus 99 +/- 2 ml/min/1.73 m2 during good control, p less than 0.01). The average renal clearance of dextran with molecular weights ranging from 25,000 to 35,000 and 35,000 to 45,000 increased during poor metabolic regulation from 14.8 +/- 0.8 to 19.8 +/- 1.8 ml/min/1.73 m2, and 5.2 +/- 0.3 to 6.8 +/- 0.6 ml/min/1.73 m2, respectively (p less than 0.05). The elevated GFR and renal dextran clearance found during poor metabolic regulation were normalized within one to three weeks of effective insulin treatment. This rapid reversibility can hardly be explained by the previously demonstrated enlargement in glomerular size and filtration surface area, since these alterations remain unchanged after more than one month of insulin treatment. The metabolic regulation did not influence the size-selective properties of the glomerular wall. Therefore, we suggest that the dominating mechanism involved in the GFR and renal dextran clearance alterations is functional, viz. increased filtration pressure.

Adolescent↗
PubMed1979

Kidney function in acromegaly.

Creatinine clearance and daily urinary albumin and beta2-microglobulin excretion rates (radio-immunoassays) were measured several times in 14 patients with acromegaly. Eleven patients were treated with bromocriptine, 5 to 55 mg/day. The activity of the disease was assessed by measuring urinary growth hormone excretion (radio-immunoassay). In agreement with previous investigations we found the creatinine clearance elevated. However, no correlation was found between this variable and urinary growth hormone excretion. Urinary albumin and beta 2-microglobulin excretion rates were not significantly different from our previous results in 27 adults control subjects. There was no correlation between urinary growth hormone excretion and urinary albumin or beta 2-microglobulin excretion rates. Bromocriptine treatment reduced urinary growth hormone excretion from 220 to 91 ng/24 hours, p less than 0.01, but no significant alterations were induced in the above mentioned kidney function variables.

Acromegaly↗
PubMed1978

Kidney function in normal man during short-term growth hormone infusion.

Kidney function was studied in 9 normal males before and during a 2 h growth hormone (GH) infusion of 50 ng/kg/min. The following variables were measured during each 20 min clearance period: glomerular filtration rate, GFR, effective renal plasma flow, RPF (steady state infusion technique with urinary collections using [125I]iothalamate and [131I]iodohippurate), and urinary albumin and beta2-microglobulin excretion rates (radioimmunoassays). The GH infusion resulted in a 10-fold increase in plasma GH concentration. All the above mentioned variables remained practically unchanged during the infusion except for a small (-5%) but significant decrease in renal plasma flow (P less than 0.01). Our negative results contrast to the findings of increased GFR and RPF during prolonged GH administration and suggest that GH requires several hours or days for its renal effects to become manifest.

Adult↗
PubMed1977

The effect of short-term glucagon infusion on kidney function in normal man.

Kidney function was studied in six normal males before and during a 2 h glucagon (10 ng/kg/min) infusion. The following variables were determined during each 20 min clearance period; glomerular filtration rate (GFR), renal plasma-flow (RPF) , filtration fraction (FF), urinary albumin and beta2-microglobulin-excretion rates. Glucagon infusion resulted in a fourfold increase in plasma glucagon concentration. The infusion induced a significant increase in GFR (+9%), FF (+9%) and urinary beta2-microglobulin excretion rate (+32%), (p less than 0.01). RPF and urinary albumin excretion rates were not significantly changed. We suggest that glucagon may contribute to the reversible kidney function alterations typically found in poorly regulated juvenile diabetes, a state with relative or absolute hyperglucagonaemia.

Adult↗
PubMed1977

Extracellular fluid volume determined by a single injection of inulin in men with untreated essential hypertension.

The extracellular volume (ECV) and plasma volume (PV) were determined simultaneously in nine men with untreated essential hypertension and in nine healthy matched control subjects, using a single injection of inulin and of 131I-labelled human serum albumin, respectively. The average mean arterial blood pressure in the hypertensive group was 178/118 mmHg. ECV was nearly the same in the two groups, viz. 151 ml/kg body weight (SD 17) in the hypertensive group compared to 147 ml/kg (SD 16) in the control group. The corresponding figures for PV were 38.2 ml/kg body weight (SD 4.7) and 43.7 ml/kg (SD 7.9) respectively (P less than 0.1). The calculated interstitial fluid volume (IV) was 113 ml/kg (SD 16) and 103 ml/kg (SD 10) (P less than 0.2). The PV/IV ratio was significantly lower (P less than 0.02) in the hypertensive group (0.34, SD 0.06) than in the normal group (0.42, SD 0.06). The difference might suggest increased transcapillary water filtration in hypertension.

Adult↗
PubMed1977

Increased transcapillary escape rate of albumin and IgG in essential hypertension.

Transcapillary escape rates of albumin and IgG (fractions of intravascular mass of albumin and IgG that pass to the extravascular space per unit time) were determined simultaneously from the initial disappearance of intravenously injected 131I human albumin and 125I human IgG in seven untreated subjects suffering from essential hypertension. The average mean arterial blood pressure of these subjects 193/119 mmHg; four subjects had grade I-III funduscopic changes. Transcapillary escape rates of albumin (TERalb) and IgG (TERIgG) were found significantly increased in the hypertensive subjects, average 7.8 +/- 0.9 (SD) and 4.7 +/- 1.0 (SD) %/h, respectively, compared with normal values of mean 5.2 +/- 1.0 (SD) and 3.0 +/- 0.7 (SD) %/h, respectively (P less than 0.01). There was a statistically significant positive correlation between the mean arterial blood pressure and TER of albumin and of IgG (P less than 0.001). The TERIgG/TERalb ratio was about the same in the hypertensives and the normals. Confirming a previous observation, we found an increase in the daily urinary albumin excretion rate from a normal average of 9.1 (range, 2.4-20.4)mg/24 h to 96 (range, 5.6-565) mg/24 h, P less than 0.05. The present findings can best be explained by increased filtration through normal pores between the endothelial cells in the microvasculature, due to the high arterial blood pressure.

Adult↗
PubMed1977

Increased transcapillary escape rate of albumin in patients with cirrhosis of the liver.

The transcapillary escape rate of albumin (TERalb), i.e. the fraction of intravascular mass of albumin that passes to the extravascular space per unit time, was determined from the disappearance of intravenously injected 125I-labelled human serum albumin during the first 60 min after injection in nine patients with cirrhosis of the liver. Six of the patients had ascites. The wedged hepatic venous pressure or splenic pulp pressure ranged from 20 to 30 mmHg, mean 26 mmHg. Plasma albumin concentration was low, but plasma volume was slightly enlarged, and thus the intravascular mass of albumin was only moderately reduced. The transcapillary escape rate of albumin was significantly elevated in all the cirrhotics, mean 10.2%/h, range 8.8 to 12.3%/h, in comparison to values for twenty-eight normal subjects 5.4%/h, range 3.5-7.2%/h. Our results can best be explained by increased filtration out of the vessels in the portal system, due to the increased portal venous pressure. The increased TERalb probably contributes to the formation of oedema and ascitic fluid.

Adult↗
PubMed1977

Trisomy 8 syndrome. A psychological and somatic study of a mentally non-retarded male with 46,XY/47,XY,+8 chromosome constitution.

A 27-year-old, non-retarded male with trisomy 8 mosaicism (46,XY/47,XY,+8) had a short head, a short broad-bridged nose, a protruding upper lip, pterygium colli, moderate kypho-scoliosis, camptodactyly of all fingers and deep furrowing on the soles. Radiographic examination of columna showed spina bifida of L1 and fusion of L5 and S1. These findings are characteristic for the trisomy 8 syndrome. A psychological study showed a personality characterized by immaturity and lack of spontaneity and self-confidence. An intelligence test (WAIS) placed him within the normal range, but presented an uneven development of the cognitive functions with special difficulties in synthetic abilities and visual scanning. His auditive span was rather low, and his memory functions were somewhat below average.

Abnormalities, Multiple↗
PubMed1976

The effect of metabolic regulation on microvascular permeability to small and large molecules in short-term juvenile diabetics.

The microvascular permeability to small and large molecules was studied during good and poor metabolic regulation in ten short duration juvenile diabetics. The following variables were measured; daily urinary albumin and beta2-microglobulin-excretion rates, whole body transcapillary escape rate of albumin (TER), glomerular filtration rate (GFR), capillary filtration coefficient (CFC), and capillary diffusion capacity (CDC). The urinary albumin and beta2-microglobulin concentration were measured by sensitive radioimmunoassays; TER was detemined from the initial disappearance of intravenously injected 125I-labelled human serum albumin; GFR was measured on the forearm by straingauge plethysmography and CDS for 51Cr-EDTA clearance; CFC was measured on the forearm by straingauge plethysmography and CDC, for 51Cr-EDTA was determined in the jyperaemic anterio tibial muscle by the local clearance technique. All the above mentioned variables, except CDC, were significantly increased during poor metabolic regulation, indicating a functional microangiopathy. The mechanisms of these alterations appear to be increased filtration pressure in the microcirculation and/or increased porosity of the microvasculature. The findings of increased microvascular albumin passage are compatible with the hypothesis that the organic - histologicallly demonstrated - diabetic microangiopathy is a long-term effect of periods of increased extravasation of plasma proteins, with subsequent protein deposition in the microvascular wall, i.e. the concept to plasmatic vasculosis.

Adolescent↗
PubMed1976

Plasma volume, intravascular albumin and its transcapillary escape rate in patients with extensive skin disease.

Plasma volume and plasma concentration and transcapillary escape rate of albumin (TER alb), i.e. the fraction of intravascular mass of albumin that passes to the extravascular space per unit time, were determined using 125I-labelled human albumin in eight patients with extensive skin disease. Plasma volume and plasma albumin concentration were reduced (P less than 0-05). Thus the intravascular albumin mass was moderately decreased to an average of 0-55 +/- 0-06 (s.d.) g/cm height compared with a normal mean value of 0-77 +/- 0-07 (s.d.) g/cm. This 29% decrease is statistically significant (P less than 0-001). The transcapillary escape rate of albumin (TER alb) was significantly elevated, mean 8-6 +/- 1-1 (s.d.) % X h-1, as compared to normal subjects, mean 5-6 +/- 1-1 (s.d.) % X h-1, (+54%, P less than 0-001). The same patients were studied again after a 1-week treatment with prednisone, 25-60 mg per day. Plasma albumin concentration, plasma volume and intravascular mass of albumin were unchanged, while TER alb decreased significantly during treatment, mean 5-9 +/- 0-8 (s.d.) % X h-1, (P less than 0-01). It is suggested that displacement of albumin into the skin and loss of albumin from the skin are the dominating mechanisms of the reduction in the intravascular albumin mass in patients with extensive skin disease.

Aged↗