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Biomedical subjects

A Halabe

Publications and source records attributed to A Halabe.

26 records · Page 2Linked to original sources
PubMed1987

"Idiopathic" hypercalciuria and hereditary hypophosphatemic rickets. Two phenotypical expressions of a common genetic defect.

Among 59 closely related members of one Bedouin tribe, we identified 9 who had the characteristic features of hereditary hypophosphatemic rickets with hypercalciuria (HHRH). We found "idiopathic" hypercalciuria in 21 of the 50 asymptomatic members. The biochemical abnormalities observed in these 21 subjects were qualitatively similar to those in the 9 with HHRH, but were quantitatively milder. The urinary calcium concentration was 0.43 +/- 0.14 mg per milligram of creatinine (mean +/- SD) in the patients with HHRH, 0.34 +/- 0.07 in the subjects with idiopathic hypercalciuria, and 0.14 +/- 0.05 in normal subjects from the same tribe. Tubular reabsorption of phosphorus and serum phosphorus concentrations were 3.0 and 4.3 SD units below the age-related mean, respectively, in HHRH, and 1.1 SD units below the normal mean for both variables in idiopathic hypercalciuria. Mean serum levels of 1,25-dihydroxyvitamin D (1,25-(OH)2D) were 303 pg per milliliter in HHRH and 145 pg per milliliter in idiopathic hypercalciuria (upper normal limit, 110). We conclude that the subjects with hypercalciuria and the patients with HHRH shared a hereditary renal phosphate leak that led to hypophosphatemia, elevated serum concentrations of 1,25-(OH)2D, increased intestinal calcium absorption, and hypercalciuria. The magnitude of the hypophosphatemia, which regulates 1,25-(OH)2D levels, appears to determine which subjects will have hypercalciuria alone and which will also have bone disease.

Adolescent↗
PubMed1985

Hereditary hypophosphatemic rickets with hypercalciuria.

We studied a new hereditary syndrome of hypophosphatemic rickets and hypercalciuria in six affected members of one kindred. In all patients, the manifestations of disease began in early childhood. The characteristic features are rickets, short stature, increased renal phosphate clearance (the ratio between the maximal tubular reabsorption rate for phosphorus and the glomerular filtration rate [TmP/GFR] is 2 to 4 S.D. below the age-related mean), hypercalciuria (8.6 mg of urinary calcium per kilogram of body weight per 24 hours vs. the upper normal value of 4.0), normal serum calcium levels, increased gastrointestinal absorption of calcium and phosphorus, an elevated serum concentration of 1,25-dihydroxyvitamin D (390 +/- 99 pg per milliliter vs. the upper normal value of 110), and suppressed parathyroid function (an immunoreactive parathyroid hormone level of 0.33 +/- 0.1 ng per milliliter and a cyclic AMP level of 1.39 +/- 0.12 nmol per deciliter of glomerular filtrate vs. the lower normal values of 0.3 and 1.5, respectively). Long-term phosphate supplementation as the sole therapy resulted in reversal of all clinical and biochemical abnormalities except the decreased TmP/GFR. We propose that the pivotal defect in this syndrome is a renal phosphate leak resulting in hypophosphatemia with an appropriate elevation of 1,25-dihydroxyvitamin D levels, which causes increased calcium absorption, parathyroid suppression, and hypercalciuria. This syndrome may represent one end of a spectrum of hereditary absorptive hypercalciuria. Our observations support the importance of phosphate as a mediator in controlling 1,25-dihydroxyvitamin D production in human beings.

Calcium↗
PubMed1985

Hypercalciuric rickets: metabolic studies and pathophysiological considerations.

Extensive metabolic studies were performed in a 14-year-old boy suffering from the rare clinical entity known as childhood idiopathic hypercalciuria associated with dwarfism, renal tubular abnormalities and bone lesions. The salient features were: hyperphosphaturia with hypophosphatemia, hypercalciuria with normocalcemia, elevated serum 1,25-dihydroxycholecalciferol[1,25(OH)2D3] levels, marked intestinal hyperabsorption of calcium and phosphorus, with low serum parathyroid hormone (PTH) and urinary adenosine 3':5'-cyclic monophosphate (c-AMP). Bone biopsy confirmed the clinical and radiological diagnosis of rickets. It appears that the following pathophysiological sequence is operating: primary renal phosphate leak with hypophosphatemia, increased 1,25(OH)2D3 synthesis, enhanced intestinal calcium absorption which in turn inhibits release of PTH and c-AMP. Hypercalciuria is seen to be secondary to both avid intestinal calcium absorption and depressed PTH activity, and rickets the result of phosphate depletion. Treatment with oral phosphorus only resulted in an acceleration of growth rate, cure of rickets, and return of urinary calcium excretion to normal values.

Adolescent↗
PubMed1980

End-organ resistance to 1,25-dihydroxycholecalciferol.

A 13-year-old girl with total alopecia who in infancy had rickets unresponsive to large doses of vitamin D2 is described. She had profound hypocalcaemia which was resistant to treatment with high doses of dihydrotachysterol, 1 alpha-hydroxycholecalciferol, and 1,25-dihydroxycholecalciferol. Serum concentrations of 25-hydroxyvitamin D were normal but those of 1,25-dihydroxycholecalciferol were markedly raised (674 and 745 pg/ml). In addition, 24,25-dihydroxyvitamin D was undetectable in serum. Administration of synthetic 24,25-dihydroxycholecalciferol was followed by normocalcaemia which persisted long after treatment was stopped. Her sister, who died at the age of 10 months, also had had total alopecia, rickets, and hypocalcaemia resistant to vitamin-D2 therapy. In this familial syndrome there seems to be end-organ resistance to the action of 1,25-dihydroxycholecalciferol, possibly as a result of changes at the receptor sites.

Adolescent↗
PubMedDate not supplied

Spherulite crystals in synovial tissue of a patient with recurrent monoarthritis.

Frozen, unstained sections of synovial tissue of a 38-year-old man with recurrent monoarthritis and hyperuricemia were studied. Negatively birefringent crystals in a spherulite form were detected by using a compensated polarized light microscope. It is postulated that in some cases of gout the first stage of crystallization is in the spherulite form.

Adult↗