Search PubMed⌕ Search

Biomedical subjects

W E Huffer

Publications and source records attributed to W E Huffer.

At least 37 records · Page 2Linked to original sources
PubMed1982

Studies on the pathogenesis of avian rickets II. Necrosis of perforating epiphyseal vessels during recovery from rickets in chicks caused by vitamin D3 deficiency.

This study involved comparison of the distribution and integrity of perforating epiphyseal and marrow vessels with the stage of development and integrity of chondrocytes and the distribution of insoluble calcium in the proximal tibial growth plate of 3-week-old vitamin-D3-deficient hypocalcemic chicks and 3-week-old D3-deficient chicks 12, 36, 72, and 120 hours after an oral dose of 10,000 units vitamin D3. The aim was to clarify the mechanisms responsible for chondrocyte hypertrophy and cartilage calcification in the avian growth plate. Within 12 hours after administration of vitamin D3, serum calcium levels rose to normocalcemic levels. The following morphologic changes were first recognizable at the times indicated. Distal portions of previously elongated perforating epiphyseal vessels and adjacent proliferative and maturing chondrocytes underwent necrosis by 12 hours. Chondrocyte necrosis was not preceded by hypertrophy. By 36 hours, vascular and chondrocyte necrosis involved large portions of the thickened proliferating and maturing zone, and perforating epiphyseal vessels were shortened to a normal length. By 72 hours, chondrocyte hypertrophy and calcification resumed around the shortened epiphyseal vessels. By 120 hours, marrow had removed the necrotic cartilage, and morphologically normal growth plate was restored, with perforating epiphyseal and marrow vessels, both ending in a narrow hypertropic cartilage zone. The results indicate that proximity of chondrocytes to perforating epiphyseal vessels is necessary for their viability, but loss of these vessels does not cause hypertrophy. Since hypertrophy and calcification both occur in the proximity of perforating epiphyseal vessels in normocalcemic animals but not in hypocalcemic animals, it is likely that the vessels influence hypertrophy and calcification by delivering calcium to chondrocytes.

Animals↗
PubMed1982

Studies on the pathogenesis of avian rickets. I. Changes in epiphyseal and metaphyseal vessels in hypocalcemic and hypophosphatemic rickets.

Growth plate morphometry and measurements of serum chemistry were correlated to clarify the pathogenesis of hypocalcemic and hypophosphatemic avian rickets. Accumulation of proliferating and maturing cartilage in hypocalcemic chicks is accompanied by increased length and increased variation in length of perforating epiphyseal vessels, decreased number and abnormal arrangement of marrow spaces, an increased proportion of cells to blood vessels in marrow spaces, and a change in the distribution but not the total number of DNA-synthesizing chondrocytes per unit width of growth plate. Accumulation of hypertrophic cartilage in hypophosphatemic rickets is accompanied by no change in length, distribution, or number of perforating epiphyseal vessels, elongation but no change in number or arrangement of marrow spaces, an increase in the relative proportion of blood vessels to cells in the marrow spaces, and no change in distribution but a decrease in total number of DNA-synthesizing chondrocytes per unit width of growth plate. Both types of rickets have decreased amounts of calcified cartilage. These results provide further evidence that hypocalcemia and hypophosphatemia cause morphologically distinct types of rickets in birds. The data indicate that the thickness of the proliferating and maturing region and hence the distance of the hypertrophic zones from the epiphysis are anatomically and temporally related to length of perforating epiphyseal vessels and serum calcium levels. They indicate that in hypocalcemic rickets accumulation of proliferating and maturing cartilage is unlikely to be the result of increased chondrocyte replication and that the relative rates of chondrocyte hypertrophy and resorption of hypertrophic cartilage by marrow are equal. They support the concept that delayed chondrocyte hypertrophy is the major cause of growth plate thickening in hypocalcemic rickets. Data presented in this study, when considered together with data from the literature on hypophosphatemic rickets, support the long-held concept that growth plate thickening in this disease is caused primarily by a decreased rate of resorption of hypertrophic cartilage by marrow relative to the rates of chondrocyte proliferation, maturation, and hypertrophy. The data further support the concepts that growth of cartilage into marrow is a biphasic process including longitudinal growth effected mainly by blood vessels, and resorption of the lateral walls of marrow spaces effected mainly by marrow cells, and that it is the latter phase that is defective in hypophosphatemia.

Animals↗
PubMed1981

Calcification in end-stage kidneys.

This study was carried out to determine the frequency and to quantitate the severity calcium-phosphate deposits in end-stage kidneys. In 57 of 59 end-stage kidneys obtained from patients with a variety of different renal diseases, calcium levels were greater than 2 standard deviations (SD) above control values. The mean calcium concentration was 157 +/- 24 mmol/kg dry defatted tissue in the end-stage kidneys as compared to 17 +/- 1 mmol/kg in the control kidneys. Histologically, calcium was deposited in the cortical tubular cells, basement membranes and interstitium. It would appear that calcification occurred during the course of renal failure rather thant terminally in that the kidney calcium concentration bore no relationship to the calcium X phosphate product, and the calcium concentration in the kidneys of uremic patients undergoing dialysis (144 +/- 23 mmol/kg) was no greater than that found in uremic patients not undergoing dialysis (188 +/- 62 mmol/kg). It is suggested that calcification may damage the diseased kidney accelerating the rate of renal functional deterioration.

Adolescent↗
PubMed1980

Controlled trial of the effects of 1,25-dihydroxycholecalciferol in patients treated with regular dialysis.

In a double-blind controlled study, 15 patients received 1,25-dihydroxycholecalciferol (1,25[OH]2D3) (0.5-1.5 microgram/day) and 16 patients received vitamin D3 (D3) (400-1,200 IU/day). The patients receiving 1,25(OH)2D3 had a rise in mean serum calcium concentration from 9.05 +/- 0.15 to 10.25 +/- 0.20 mg/dl (p less than .001) with a return to 9.37 +/- 0.16 (p less than .001) in the post-control period; however, hypercalcemia (greater than 11.5 mg/dl) occurred in 5 of 15 patients. Likewise, patients who received 1,25(OH)2D3 but not those given D3 had a reversible decrease in immunoreactive parathyroid levels. 9 of 12 patients given D3 had serial iliac crest bipsies showing histologic deterioration, while 6 of 7 patients who received 1,25(OH)2D3 were improved or unchanged (p less than 0.025). Bone mineral and calcium content decreased in patients on D3 (p less than .05) but not in those on 1,25(OH)2D3. We conclude that the administration of 1,25(OH)2D3 to dialysis patients: (1) has a calcemic effect. (2) decreases levels of immunoreactive parathyroid hormone, and (3) is associated with histologic improvement in bone disease.

Adult↗
PubMed1979

The hematopoietic effects of prednisone therapy in four infants with osteopetrosis.

Sequential hematologic studies were performed in four infants with malignant osteopetrosis who received prednisone. Prednisone therapy resulted in decreased liver and spleen size, decreased numbers of circulating immature blood cells, and increased hemoglobin concentration and platelet counts in all infants. The quantity and quality of hematopoietic tissue in bone marrow biopsies improved during prednisone therapy but showed no significant improvement without therapy. Sequential indium 111 chloride scans in one infant showed increased uptake in long bones and pelvis and decreased uptake in liver and spleen during therapy. We conclude that prednisone therapy of infantile osteopetrosis results in increased bone marrow hematopoiesis and decreased extramedullary hematopoiesis.

Hematopoiesis↗
PubMed1978

Preservation of function in experimental renal disease by dietary restriction of phosphate.

We sought to determine the importance of calcium phosphate deposition in the functional deterioration of damaged or diseased kidneys. Using the remnant-kidney model in rats, we found that dietary phosphate restriction prevented proteinuria, renal calcification, histologic changes, functional deterioration and death in uremia. Histologic examination of the remnant kidney in the nonrestricted animals showed calcium and phosphorus deposits in the cortical tubular cells, basement membranes and interstitium. A similar degree and pattern of calcification have been found in preliminary studies of human end-stage kidneys. Our results suggest that the calcification produced by the altered phosphorus metabolism present in the uremic state incites an inflammatory and fibrotic reaction leading to destruction of the remnant kidney. Phosphate restriction prevents this response in the remnant kidney. The potential applicability of these findings to other forms of experimental renal disease and to clinical uremia remains to be explored.

Animals↗
PubMed1978

Resolution and repair of elastic tissue calcification in pseudoxanthoma elasticum.

Biopsy specimens of a skin lesion from a patient with pseudoxanthoma elasticum were obtained at the beginning and end of a 1 1/2-year period of clinically documented regression of the lesion. Light microscopic studies of these specimens showed that, during the period of regression, there was a decrease in the number of abnormal calcified elastic fibers in the dermis. Electron microscopic findings were interpreted as indicating breakdown and removal of mineralized elastic fibers at the beginning and formation of new elastic fibers at the end of the regression period. Cytoplasmic processes of active fibroblasts were intimately associated with fibers undergoing dissolution. The case thus represents a clinically and morphologically documented example of resolution and repair of elastic tissue calcification.

Biopsy↗
PubMed1977

Soft tissue calcification in chronic dialysis patients.

Autopsy protocols and microscopic slides of 56 dialyzed and 18 nondialyzed chronically uremic patients were reviewed to assess the presence, extent, and severity of extraosseous soft tissue calcification. Calcification was identified in 79% of the dialysis patients and 44% of the nondialysis patients (P iss less than .025). Soft tissue calcification most frequently involved the heart, lungs, stomach, and kidneys. Lesions were severe in 36% of the dialysis patients and, when strategically located within the myocardium, were life-threatening. The deaths of 6 dialysis patients were attributed to severe calcification of the cardiac conduction system and/or myocardium. The presence and severity of soft tissue calcification was not related to duration of dialysis, patients' age, degree of parathyroid gland hyperplasia, radiographic evidence of soft tissue calcification, serum calcium and phosphate levels, Ca X P products, or type or severity of metabolic bone disease.

Adolescent↗
PubMed1976

Effects of alternating phosphorus and calcium infusions on osteoporosis.

The osteoblastic effect of inorganic phosphorus and the inhibitory action of calcium on parathyroid hormone secretion formed the basis for a therapeutic trial in which both elements were given intravenously in an alternating sequence for one year to five patients with severe osteoporosis. During treatment, calcium and phosphorus balances were positive, and serum phosphorus concentrations decreased. Iliac crest bone biopsy specimens obtained one year after beginning treatment demonstrated an increase in the thickness of cortical bone. All patients experienced lasting relief of bone pain, and the rate of spontaneous fractures decreased from at least one fracture per year to none following the beginning of treatment. These findings suggest that long-term treatment with alternating phosphorus and calcium infusions may result in lasting relief of symptomatic osteoporosis. It is proposed that the observed improvement reflects an increase in bone mass resulting from enhanced bone formation.

Aged↗
PubMed1975

Pulmonary calcification in chronic dialysis patients. Clinical and pathologic studies.

A prospective study of 31 chronically hemodialyzed patients was made to investigate the incidence and pathology of pulmonary calcification and the relation of the latter to ventilatory function. Fifteen of the patients have died thus far; 9 had evidence of lung calcification. The lesions occurred predominately in alveolar septa and were associated with varying degrees of fibrosis and alveolar septal thickening. Only one patient had X-ray evidence of calcification. An X-ray diffraction analysis showed a predominant pattern of whitlockite (CaMg)3(Po4)2 in deposits. Patients with the severest pulmonary calcification had abnormalities of vital capacity, carbon monoxide diffusion, and Po2. Serum calcium levels were slightly higher in patients with calcification, but there was no measurable association with the duration of dialysis, serum phosphorus, calcium X phosphorus product, magnesium, bicarbonate, or arterial pH. These data show that pulmonary calcification occurs with high frequency in patients undergoing long-term hemodialysis and that such lesions are associated with restrictive and diffusion ventilatory defects.

Adult↗
PubMed1975

Metabolic bone disease in chronic renal failure. II. Renal transplant patients.

Trabecular vertebral bone of renal transplant patients was quantitatively compared with bone from normal individuals and dialyzed and nondialyzed patienets with chronic renal failure reported in detail in an earlier study. Long- and short-term transplant patients have increased bone resorption and mineralization defects similar to renal osteodystrophy in dialyzed and nondialyzed patients. However, in transplant patients the magnitude of resorption is greater, and bone volume tends to decrease rather than increase. Resorptive activity in transplant patients is maximal during the first year after transplantation. Bone volume decreases continuously for at least 96 months after transplantation. Only decreased bone volume correlated with success or failure of the renal transplant. Morphologic findings in this study correlate with other clinical and morphologic data to suggest that reduction in bone volume in transplant patients results from a combination of persistent hyperparathyroidism and suppression of bone formation by steroid therapy.

Adult↗
PubMed1975

Metabolic bone disease in chronic renal failure. I. Dialyzed uremics.

Garner and ball's point counting technic was used to compare metabolic bone disease in dialyzed and nondialyzed uremic patients. Histologic measurements of bone from dialyzed and nondialyzed uremic patients dying between 1966 and 1971 showed that dialyzed patients have quantitatively more severe bone resorption, distortion of trabecular architecture and mineralization defects. Mineralization defects become more severe as the duration of dialysis increases but are not related to serum calcium and phosphorus levels. Bone volume in both groups is normal or increased and in dialysis patients increases in proportion to the elevation of serum phosphorus. Mean serum phosphorus and calcium levels, bone volume, and volume: surface ratios all decreased in dialysis patients between 1966 and 1971, while bone resorption and mineralization defects did not change. These results suggest that lowering of serum phosphorus without increasing serum calcium may aggrevate the uremic bone disease by reducing bone volume without improvement of mineralization and resorption defects.

Adult↗