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Biomedical subjects

R J Kallen

Publications and source records attributed to R J Kallen.

12 recordsLinked to original sources
PubMed1991

Paleonephrology and reflux nephropathy. From the 'big bang' to end-stage renal disease.

Urinary tract infections, in association with ureteral reflux or dysperistalsis, may lead to invasive renal parenchymal infection and residual scarring (reflux nephropathy). Such infections in infants are often not diagnosed during the acute phase. Late sequelae of reflux nephropathy include hypertension, proteinuria, or chronic renal failure. The latter may eventuate in the subset of patients with urinary tract infection and unilateral reflux extending to a solitary kidney or bilateral reflux. Proteinuria may herald the inexorable progression of glomerular sclerosis in patients destined to progress to end-stage renal disease, despite the absence of further recurrences of urinary tract infections. The mechanism of progression is probably similar to that occurring in other forms of chronic, diffuse parenchymal renal disease, which all have similar alterations in glomerular hemodynamics (an increase in glomerular capillary flow, pressure, and filtration). The consequent hyperfiltration per nephron may be related to the level of dietary protein intake or to some derivative of the protein load. Hyperfiltration appears to recapitulate the presumed renal hemodynamic response to the relatively high level of episodic meat consumption by paleolithic hunter-gatherers. A prudent therapeutic intervention in children with progressive reflux nephropathy may be a proportional reduction in protein intake.

Adaptation, Physiological↗
PubMed1990

The management of diarrheal dehydration in infants using parenteral fluids.

The assessment and management of an infant with diarrheal dehydration can be reduced to a set of questions. As the questions are studied and answered, the clinician arrives at a rational plan for parenteral fluid therapy, based on physiologic considerations. The selection of the type of fluid to be infused uses a decision-tree algorithm, based on knowledge of the serum sodium consideration.

Acid-Base Equilibrium↗
PubMed1990

Fluid resuscitation of acute hypovolemic hypoperfusion states in pediatrics.

Multiorgan hypoperfusion due to a loss of effective circulating blood volume, whether a consequence of hemorrhage or dehydration, constitutes a medical emergency. Fluid must be added rapidly to the circulatory system, in the form of blood, colloid, or crystalloid solution. The type of fluid used for volume expansion depends on the nature of the losses. The aim of treatment is to expand effective circulating blood volume and to restore nutrient delivery and gas exchange at the cellular level.

Child↗
PubMed1977

Premature coronary atherosclerosis in a 5-year-old with corticosteroid-refractory nephrotic syndrome.

We report the case of a 5-year-old girl who died two years after onset of the idiopathic nephrotic syndrome, which failed to respond to treatment with corticosteroid and cyclophosphamide. Severe atherosclerotic changes were noted in both coronary arteries. Prolonged hyperlipidemia in patients with long-standing nephrotic syndrome may represent a major risk factor predisposing to premature coronary atherosclerosis in children who are also destined to develop chronic renal failure.

Adrenal Cortex Hormones↗
PubMed1977

Idiopathic membranous glomerulopathy preceding the emergence of systemic lupus erythematosus in two children.

An idiopathic nephrotic syndrome associated with membranous glomerulopathy antedated the subsequent emergence of systemic lupus erythematosus in two patients (7-year-old and 14-year-old girls). At the onset of INS, there was neither clinical evidence of multisystem disease nor unequivocal serologic evidence of SLE. The only early possible indication of SLE was the presence of microtubular inclusions in glomerular endothelial cells on electron microscopy. In each instance (one year and three years after onset of INS), a second renal biopsy showed transformation of the membranous glomerular lesion to a more florid type with glomerular subendothelial dense deposits. One patient died of overwhelming pulmonary infection while she was receiving prednisone and cyclophosphamide; the other developed progressive renal failure despite steroid treatment. SLE should be considered in patients presenting with apparent idiopathic MG, in whom nephrotic syndrome persists. Intraendothelial cell microtubular inclusions may be an early clue to later emergence of SLE.

Adolescent↗
PubMed1976

Population genetics of Alport's syndrome. Hypothesis of abnormal segregation and the necessary existence of mutation.

The diagnosis of Alport's syndrome is generally not considered in the absence of a positive family history. Family studies indicate that transmission occures by a rare autosomal dominant gene. The deviation of transmission ratios from the classical Mendelian pattern is best explained by abnormal segregation. Based on observed pedigree data, calculations were made of the expected equilibrium population frequency of Alport's syndrome assuming mutation rates of zero, 10, and 50 per million gametes. Zero mutation rate should result in disappearance of the Alport gene. An equilibrium frequency corresponding to that actually observed in Rhode Island implies a mutation rate of 10 per million gametes. Furthermore, up to 18% of all newborns with the Alport genotype may represent new mutants. Thus, isolated cases of Alport's syndrome may occur in the absence of other affected family members.

Female↗
PubMed1975

Conduction system in systemic lupus erythematosus with atrioventricular block.

We describe the clinical course and the postmortem cardiac findings in a 12 year old girl with systemic lupus erythematosus, complete heart block, renal failure and hyperkalemia. The conduction system was examined by serial section. The sinoatrial and atrioventricular nodes were found to be almost completely replaced by granulation tissue; we believe that this finding is related to the systemic lupus. The hyperkalemia is not considered to be the cause of the block, since the block persisted despite the lowering of the blood potassium level and the morphologic findings in this case are not found in hyperkalemia.

Atrioventricular Node↗
PubMed1975

A study of the plasma kinin-generating system in children with the minimal lesion, idiopathic nephrotic syndrome.

Although the precise etiologic incitant of the minimal lesion idiopathic nephrotic syndrome of childhood is not known, it is likely that a host mechanism mediates the permeability alterations of the glomerular capillary wall resulting in massive proteinuria. As a first step in examining the possibility that local kinin release may account for the proteinuria in this disorder, two parameters of the plasma kinin-generating system, plasma prekallikrein and kallikrein inhibitor, were assayed during 27 nephrotic episodes in 21 corticosteroid-responsive children. Plasma kallikrein was assayed by means of its esterase activity on a synthetic arginine ester substrate, N-alpha-tosyl-L-arginine methyl ester (TAMe), after activation of Hageman factor by kaolin. This activity, after subtraction of spontaneous arginine esterase activity (i.e., TAMe esterase activity measured in plasma not exposed to kaolin) is derived from prekallikrein. Plasma prekallikrein activity in 11 normal children was 99.6 +/- 2.9 mumol TAMe hydrolyzed/ml plasma/hr (mean +/- SEM). Kallikrein inhibitor was quantified in arbitrary units. Kallifrein inhibitor activity in 11 normal children was 0.94 +/- 0.04 units. During the overt nephrotic syndrome, before initiation of intensive daily corticosteroid treatment, mean values were: prekallikrein, 58.5 +/- 7.24 mumol/ml/hr; and kallikrein inhibitor, 0.35 +/- 0.06 units. After corticosteroid-induced remission occurred, mean values were: plasma prekallikrein, 118.6 +/- 3.2 mumol/ml/hr; and kallikrein inhitor, 0.78 +/- 0.03 mumol/ml/hr. Both parameters were again assayed in 14 of the 21 children after complete cessation of corticosteroid treatment. Plasma prekallikrein was normal, 99.6 +/- 4.8 mumol/ml/hr; but kallikrein inhibitor was still somewhat depressed, 0.84 +/- 0.03 units. A subset of 9 patients had marked depression of plasma prekallikrein to levels less than 20 mumol/ml/hr and essentially undetectable inhibitor activity. Serum alpha-2 macroglobulin was elevated in nephrotic patients: mean value during relapse, 862 +/- 29 mg/100 ml; during corticosteroid-maintaining remission, 615 +/- 29 mg/100 ml. After cessation of corticosteroids, mean serum level was 481 +/- 20 mg/100 ml. The proportional reduction of plasma prekallikrein and kallikrein inhibitor suggested that an enzyme-inhibitor complex formed in vivo, perhaps at a local site of activation in proximity to the glomerular basement membrane. These data suggest that the plasma kinin-generating system may be the host effector mechanism subserving the increased glomerular capillary permeability in the minimal lesion nephrotic syndrome of childhood.

Aprotinin↗