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Biomedical subjects

H J Baluarte

Publications and source records attributed to H J Baluarte.

At least 55 records · Page 3Linked to original sources

The utility of renin profiling in childhood hypertension.

Criteria to categorize children as having hypertension associated with high, low or normal PRA as determined by the technique of renin sodium indexing; or with PRA responsiveness which was normal, suppressed or excessive after acute volume depletion induced by a loop diuretic were established in 30 normotensive adolescents. Four hour upright PRA corrected for daily sodium excretion was elevated in 16% of 43 and 84% of 25 children with essential and renal related hypertension. Low PRA was found in 5 of 43 and 0 of 25 children. In 36 children with essential hypertension evaluated after acute volume depletion, 4 and 5 had hyper- and hypo- responsive PRA compared to the 30 normotensive children. The application of these two approaches enables the renin angiotensin system to be systematically categorized in hypertensive children.

Adolescent↗

Carbonic anhydrase II deficiency in 12 families with the autosomal recessive syndrome of osteopetrosis with renal tubular acidosis and cerebral calcification.

Osteopetrosis with renal tubular acidosis and cerebral calcification was identified as a recessively inherited syndrome in 1972. In 1983, we reported a deficiency of carbonic anhydrase II, one of the isozymes of carbonic anhydrase, in three sisters with this disorder. We now describe our study of 18 similarly affected patients with this syndrome in 11 unrelated families of different geographic and ethnic origins. Virtual absence of the carbonic anhydrase II peak on high-performance liquid chromatography, of the esterase and carbon dioxide hydratase activities of carbonic anhydrase II, and of immunoprecipitable isozyme II was demonstrated on extracts of erythrocyte hemolysates from all patients studied. Reduced levels of isozyme II were found in obligate heterozygotes. These observations demonstrate the generality of the findings that we reported earlier in one family and provide further evidence that a deficiency of carbonic anhydrase II is the enzymatic basis for the autosomal recessive syndrome of osteopetrosis with renal tubular acidosis and cerebral calcification. We also summarize the clinical findings in these families, propose mechanisms by which a deficiency of carbonic anhydrase II could produce this metabolic disorder of bone, kidney, and brain, and discuss the clinical evidence for genetic heterogeneity in patients from different kindreds with this inborn error of metabolism.

Acidosis, Renal Tubular↗

Development of pneumatosis cystoides intestinalis following transperitoneal renal transplantation in a child.

A 9 1/2-year-old female developed pneumatosis cystoides intestinalis (PCI) which was detected radiographically 4 1/2 months after transperitoneal cadaveric renal transplantation, during a period characterized by recurrent episodes of acute rejection. Radiographic evaluation was prompted by the development of cramping abdominal pain, distention, and tenderness localized to the region of the allograft, which occurred during one such episode. Pneumatosis was localized primarily to an area of colon that lay in direct contact with the allograft. Evaluation of the available clinical and roentgenographic evidence suggested that pneumatosis may have resulted from the development of a sympathetic inflammatory reaction within the bowel wall adjacent to the acutely inflamed allograft. Subsequent stabilization of renal function was associated with resolution of the pneumatosis over the ensuing 8 months without surgical intervention or additional medical therapy.

Child↗

Transperitoneal solute movement in children.

The transperitoneal movement of solute in children was examined by means of a theoretical consideration of the peritoneal clearance formula and by the performance of peritoneal solute diffusion curves and measurement of peritoneal clearances of multiple solutes. Theoretical considerations led to the conclusion that when dialysis mechanics are held constant, peritoneal clearances scaled for weight are similar in individuals of widely varying weight when the volume of infused dialysate is also scaled for weight if peritoneal permeability and surface area are constant. In one group of studies, solute diffusion curves and weight-scaled peritoneal clearances of urea, phosphate, creatinine, and urate were similar in 3 children ages 4 to 18 months compared to 4 children ages 2.5 to 18.5 years. In a second group of studies, weight-scaled peritoneal clearances of inulin but not urea were shown to be marginally lower in 4 children who had been dialyzed longer than 6 months compared with 4 children dialyzed less than 1 month. Hypertonic glucose dialysis in these children was shown to enhance urea clearance but not that of inulin. It is concluded that comparative studies of peritoneal clearances can characterize the transperitoneal movement of solute in children of widely varying body size. Such studies are of greatest value when systematically performed and similar ratios of dialysate volumes to body pools of solute are used.

Adolescent↗

Encephalopathy in infants and children with chronic renal disease.

The examination of five pediatric patients with encephalopathy secondary to chronic renal failure has indicated a stereotyped sequence of neurologic signs and symptoms including ataxia, loss of motor abilities, myoclonus, seizures, dementia, and bulbar dysfunction. Both the patients with CNS dysfunction and a control group selected for a similar degree of renal failure had increased levels of serum phosphate, alkaline phosphatase, and parathyroid hormone. Serial EEGs in the affected group revealed progressive slowing and an increase in paroxysmal features. No specific neuropathologic findings were noted in one patient.

Brain Diseases↗

Uric acid in childhood essential hypertension.

Serum uric acid concentrations and the fractional excretion of uric acid were determined in 31 children from 3 1/2 to 18 years of age with essential hypertension. While on an unrestricted sodium intake, elevated serum values of uric acid were found in 13 of 31 (42%) of the children. After ingesting a low-sodium diet (200 mg/day) for three days, mean serum uric acid values increased by 0.7 mg/dl (P less than 0.001). There was a significant inverse correlation between the serum uric acid concentrations and fractional excretion of uric acid during the normal and low-sodium diet. This study indicates that the major factor leading to hyperuricemia in our hypertensive patients was a decrease in urate clearance. Insofar as hyperuricemia may represent a cardiovascular risk factor, this abnormality already exists in a significant fraction of hypertensive children and adolescents.

Adolescent↗

Bacteremia due to Bacteroides fragilis after elective appendectomy in renal transplant recipients.

Bacteremia caused by Bacteroides fragilis occurred in four of 75 children after renal transplantation, and B. fragilis was the most common cause of postoperative bacteremia. Bacteroides bacteremia was significantly associated with performance of elective appendectomy at the time of transplantation (P less than 0.01) and with profound lymphocytopenia (P = 0.01). No patient received antibiotics at the time of surgery or prior to the first positive blood culture, yet B. fragilis was the single organism isolated from blood and abscesses in these patients. A role for lymphocytes in containment of B. fragilis has not been suggested previously, although unexplained occurrence of bacteroides bacteremia in immunocompromised patients has occasionally been reported. Lymphocytes themselves may be important in this host-bacterium interaction, or lymphocytopenia may be the marker for a more generalized deficiency in host defenses.

Adolescent↗

Development aspects of peritoneal dialysis kinetics in dogs.

To determine whether solute transfer during peritoneal dialysis is age related and to identify those factors which might explain age-related differences in dialysis kinetics, the peritoneal dialysance of [14C]urea (DU), [3H]inulin (DI), and the permeability index (DR = DI/DU) were examined in six puppies and five adult dogs. Exchange volume of lactated Ringer's (40 ml/kg) and exchange times (30 min) were identical in all studies. Theoretical calculations for urea dialysance for animals of differing body size were made. Assuming the existence of a similar functional peritoneal surface area per kg and the use of similar exchange volumes per kg and dwell times, theoretical values for the urea dialysance per kg for different sized animals were identical. The experimental studies demonstrated that DI per kg and DU per kg were higher in the puppies (0.146 +/- 0.023 and 0.765 +/- 0.054 ml/min kg; X +/- S.E.) than in the adult (0.052 +/- 0.01 and 0.462 +/- 0.05 ml/min/kg) (P less than 0.01). Also, DR was higher in the puppies (0.187 +/- 0.026), than in the adults (0.11 +/- 0.015) (P less than 0.05). The greater values for DI and DU per kg and DR in the young are best explained by the young having an increased peritoneal membrane permeability as well as an increase in functional peritoneal surface area relative to body weight. This increase in solute movement is independent of the dialysis mechanics used in an exchange and reflects age-related differences in the intrinsic characteristics of the peritoneal membrane.

Age Factors↗

Improved hemodialysis access in children.

Vascular access for chronic hemodialysis in children is difficult because of problems that include obtaining vessels of sufficient size, the limited life-span of external shunts, and the multiple painful punctures associated with internal fistulae. Twenty-five expanded polytetraflouroethylene (PTFE) grafts of 6-mm diameter were inserted for dialysis access over a 2-yr period in 23 children. Grafts were placed either in the upper arm or thigh. Each patient was successfully dialyzed from 60 to 370 times. Longterm patency of the PTFE grafts was 88%, with a complication rate of 36%, mostly minor. The same ease of insertion and high flow characteristics were noted in a series of 22 bovine carotid heterograft (BCH) fistulae inserted in the two years immediately preceeding this study. However, the patency rate was only 36% and the complication rate was 69%, mostly major. We consider the PTFE graft fistula to be the preferred method for long-term hemodialysis access in children.

Adolescent↗

Hypochloremic alkalosis in infants associated with soy protein formula.

Thirteen infants, 2 to 10 months of age, developed hypochloremic alkalosis (serum chloride 59 to 92 mEq/l) while taking Neo-Mull-Soy (Syntex), a soy-based formula low in chloride (measured to be 0 to 2 mEq/l) but with considerable potassium citrate. Range of symptoms included lethargy, anorexia, mild spitting up, diarrhea, hematuria, and growth failure. Urine chloride excretion was less than 3 mEq/l. Plasma renin activity or aldosterone, measured in six infants, was elevated. All responded promptly to supplemental salt. One infant receiving Neo-Mull-Soy redeveloped alkalosis when supplemental salt was discontinued. Two of nine apparently normal infants receiving Neo-Mull-Soy also had hypochloremia (85, 86 mEq/l). Three of four receiving Prosobee (Mead Johnson; Cl content 7 mEq/l) had urine chloride concentration less than 20 mEq/l. The chloride content of some infant formulas is insufficient to offset salt losses following mild stress.

Alkalosis↗

Cefazolin in children with renal insufficiency.

Cefazolin (7 mg/kg) were administered to 11 children with renal insufficiency and to ten children on hemodialysis. The serum half-life of the drug was progressively prolonged as glomerular filtration rate fell. The serum half-life of cefazolin was variably prolonged in those children on hemodialysis, but their serum levels of cefaxolin had dropped by 35 to 65% during dialysis. Most had no measurable level prior to the next dialysis. Dosage recommendations are made for both groups of patients.

Adolescent↗

Heterophile antibodies in the serum of children with nephrotic syndrome.

Serum of children with the nephrotic syndrome contained high titers of a (19S) IgM antibody against sheep, horse, guinea pig, rat, and rabbit red blood cells but not against cow red blood cells. There was high correlation between high titers of antisheep antibodies and active nephrotic syndrome in the children with minimal change nephrotic syndrome. The antibody differed from the Paul-Bunnell antibody found in patients with infectious mononucleosis and from the anti-Forssman, Hangautziu-Deicher antibody found in patients with horse serum sickness. Rabbit red blood cells completely absorbed the antibody, but horse or guinea pig red blood cells removed only the anti-Forssman activity.

Animals↗