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Biomedical subjects

W J Stone

Publications and source records attributed to W J Stone.

At least 19 recordsLinked to original sources
PubMed1994

Loss of neurofibromin in adrenal gland tumors from patients with neurofibromatosis type I.

The neurofibromatosis type I gene encodes a protein, neurofibromin, which may function as a tumor suppressor gene product. Recent studies have demonstrated loss of neurofibromin in tumors from NF1 and non-NF1 patients, including neurofibrosarcomas, neuroblastomas and malignant melanomas. Since neurofibromin is expressed in the adrenal gland, six pheochromocytomas and one adrenal cortical tumor were examined for neurofibromin expression. In all seven tumors, no neurofibromin could be detected. Furthermore, loss of heterozygosity (LOH) analysis demonstrated that in one of the pheochromocytomas, reduction to homozygosity was observed for both 17p and 17q markers while the adrenal cortical tumor demonstrated LOH for only 17q markers. The frequent LOH surrounding the NF1 locus and lack of neurofibromin expression in these tumors suggest that NF1 gene mutations may contribute to the development of adrenal gland neoplasms in patients with NF1.

Adrenal Gland Neoplasms↗
PubMed1992

Employee physical activity: how does it compare to the nation?

1. Working adults exercise as much as the rest of society. 2. The amount of physical activity declines with age until 55, at which point increases were observed. 3. Marriage appears to have the largest effect on reducing the amount of physical activity a person gets. 4. Males are 1 1/2 times more likely than females to be vigorously active.

Adult↗
PubMed1991

Page kidney: case report and review of the literature.

Page kidney is caused by the accumulation of blood in the perinephric or subcapsular space, resulting in compression of the involved kidney, renal ischemia, and high renin hypertension. Most patients are young hypertensives with a remote history of blunt trauma to the abdomen or back. We describe a case of acute Page kidney following a renal biopsy in a patient with underlying IgA nephropathy. In addition to the new-onset hypertension, this patient developed a significant decline in renal function due to the inability of the contralateral diseased kidney to compensate. Magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound were valuable in making this diagnosis. Medical and surgical therapeutic options were considered. This report also reviews all previously described cases of Page kidney.

Adult↗
PubMed1990

Effects of dialysis membranes on beta 2-microglobulin production and cellular expression.

We investigated the effects of different dialysis membranes on the production of beta 2-microglobulin (beta 2m) in peripheral blood mononuclear cell cultures (PBMNC) obtained from hemodialysis patients in a prospective cross-over design study. Chronic dialysis with cuprophane membrane leads to an increase in beta 2m production from 129 +/- 11 ng/ml to 192 +/- 23 ng/ml (P less than 0.002). This increase is reversed by the use of a non-complement activating membrane polymethylmethacrylate. In addition, during chronic dialysis with cuprophane membrane, an increasing proportion of these cells display low beta 2m expression on their surface (from 6.1 +/- 0.8% of PBMNC to 16.9 +/- 3.4%, P less than 0.001), concomitant with the emergence of cells with low density of HLA on their surface (from 4.9 +/- 1.2% of cells to 32.9 +/- 7.8% of cells, P less than 0.001). The total content of cell-associated beta 2m is also decreased in dialysis patients in general, and in particular in patients chronically dialyzed with new cuprophane membrane. These effects can be reproduced by incubation of PBMNC with cuprophane membranes, and with the addition of C5a, IL-1 and TNF in vitro. Thus, chronic dialysis with cuprophane membrane may be a factor in the genesis of high beta 2m levels and causes changes in beta 2m and HLA expression on cell surfaces.

Aged↗
PubMed1990

Re-evaluation of the plasma renin-angiotensin system in anephric patients.

In view of recent observations that a number of extrarenal tissues have the potential to produce angiotensin II and release it in a regulated fashion, we made measurements of immunoreactive angiotensin I (irAng I) and angiotensin II (irAng II), along with active and inactive renin, and angiotensinogen in plasma of seven anephric patients and of 16 normal healthy volunteers to gain insight into possible sources of plasma Ang II. High performance liquid chromatography clearly demonstrated that the predominant component of irAng II in anephric plasma is the biologically active octapeptide Ang II. Plasma renin activity (PRA), and active and inactive renin all were detected in all of the anephrics but their levels were decreased to 33% for PRA, 12% for active renin, and 18% for inactive renin when compared with those in healthy subjects. While plasma angiotensinogen was significantly but only slightly increased in anephric patients (+28% over the mean value for normal subjects), irAng I and irAng II both were present in quantities almost comparable with those in normals. These results suggest that local angiotensin production contributes, in part at least, to the circulating plasma Ang II. Vascular tissue seems to be the best candidate responsible for such a mechanism, on the basis of recent demonstrations of unequivocal, regulated release of Ang II from diverse vascular beds.

Adult↗
PubMed1990

Strongyloides infections in transplant recipients.

Solid organ transplant recipients can experience serious disease and death from infection due to the parasitic roundworm Strongyloides stercoralis. This parasite lives in soil contaminated with human feces. Domestic dogs and cats may be another reservoir. Larvae can penetrate the skin, are carried hematogenously to the lungs, migrate up the bronchial tree, and then can be passed to the upper small intestine. Autoinfection occurs in the setting of immunosuppression when invasive larvae penetrate the gut wall and cause disseminated infection. Polymicrobial sepsis is sometimes seen due to enteric organisms adhering to the parasite. Transplant recipients are at highest risk during the first 3 months posttransplant. Many organ systems may be affected. Pulmonary symptoms include cough, wheezing, sputum production, dyspnea, hemoptysis, tachypneas, and pleuritic pain. Hyperinfection, an augmentation of the normal skin-lung-intestine life cycle, occurs in roughly two-thirds of infected transplant recipients, with dissemination in the remainder. Diagnosis is made primarily by examination of the stool or intestinal secretions for ova and parasites. Occasionally, parasites are noted in the sputum. New serologic tests show promise. The parasite may remain in the host for over 25 years before immunosuppression causes either dissemination or hyperinfection. Thiabendazole given for 3 to 7 days is the treatment of choice for organ transplant recipients. Repeat courses may be needed to eradicate infection.

Adult↗
PubMed1989

Treatment of the anemia of rheumatoid arthritis with recombinant human erythropoietin: clinical and in vitro studies.

Two anemic patients with rheumatoid arthritis were treated with recombinant human erythropoietin (EPO) for 5 months. Both patients showed significant increases in hematocrit, red cell volumes, and marrow erythroid and megakaryocyte progenitor cells. No significant toxic effects from EPO were observed. These data indicate that EPO may be effective in overcoming the pathogenetic factors that limit erythropoiesis in rheumatoid arthritis.

Adult↗
PubMed1989

Serendipitous diagnosis of appendicovesical fistula by bone scan: a case report.

A 71-year-old patient had recurrent urinary tract infections for 7 years after sigmoid colectomy via a Hartmann procedure. Extensive radiological and endoscopic tests were inconclusive as to the cause of bacteriuria. Chronic back pain led to performance of a radionuclide bone scan with the incidental demonstration of a vesicoenteric fistula, confirmed at exploration. Appendectomy with resection of the involved bladder resulted in cessation of bacteriuria.

Aged↗
PubMed1989

Cocaine-associated rhabdomyolysis and acute renal failure.

We have described four male patients, aged 21 to 39 years, who had rhabdomyolysis and acute renal failure during parenteral cocaine use. This complication has only recently been attributed to cocaine. Their illnesses behaved clinically like nonoliguric acute tubular necrosis, though renal biopsies were not done. No permanent nerve, muscle, or kidney damage resulted.

Acute Kidney Injury↗
PubMed1988

Treatment of the anemia of predialysis patients with recombinant human erythropoietin: a randomized, placebo-controlled trial.

Recombinant human erythropoietin (r-HuEPO) was administered in two phases to 12 patients with chronic renal insufficiency (creatinine clearances of 0.17-0.51 ml/second [10-30 ml/minute]) and uremic anemia. In addition to the routine tests done as part of a multicenter clinical trial, our patients had serial red cell mass measurements, quantitation of bone marrow stem cells, and marrow cytogenetic analysis. During the first eight weeks (acute phase), an equal number of patients was randomized to placebo or one of three doses of r-HuEPO (50, 100 or 150 unit/kg intravenously three times weekly). All three patients receiving 150 unit/kg responded by increasing their packed cell volume (PCV) to the normal range within eight weeks. There were lesser responses in PCV at the two lower doses of r-HuEPO and no response in the placebo group. The 51Cr red cell mass also increased significantly in a dose-related manner in patients receiving r-HuEPO but did not change in the placebo group. Marrow studies revealed increases in erythroid, megakaryocyte, and granulocyte-monocyte progenitor cells in those patients on r-HuEPO, but no mutagenic effects were seen. Subsequently, ten patients received open label r-HuEPO. During this maintenance phase, all ten achieved or maintained a normal PCV. Several adverse events occurred, but none were definitely linked to r-HuEPO. Recombinant human erythropoietin is an effective and potent treatment of anemia caused by renal failure.

Aged↗
PubMed1988

Effects of recombinant erythropoietin on the concentration and cycling status of human marrow hematopoietic progenitor cells in vivo.

The concentration of human marrow progenitors CFU-E, BFU-E, CFU-GM, and CFU-Mk and the percentage of these progenitor cells in DNA synthesis were studied in nine patients with transfusion-dependent anemia of end-stage renal failure before and 2 weeks after treatment with human recombinant erythropoietin (Epo) at a dose of 150 to 300 U/kg intravenously three times per week. The concentration of CFU-E in the posttreatment marrow increased by a mean of 4.15-fold, BFU-E by 3.37-fold, CFU-GM by 1.86-fold, and CFU-Mk by 1.96-fold as compared with their respective concentrations in the pretreatment marrows. This increase in the concentrations of marrow progenitors was accompanied by almost a doubling of the percentage of these cells in DNA synthesis as assessed by the 3H-thymidine suicide technique. These observations demonstrate that at the progenitor cell level the human marrow responds to therapeutic doses of Epo as an organ rather than by a selective expansion of the erythroid cell line.

Anemia↗
PubMed1987

Psoas abscess in chronic dialysis patients.

We report 4 cases of nontuberculous psoas abscess occurring in patients with end stage renal disease. Fever and pain were the presenting symptoms but diagnosis was delayed. A computerized tomography scan of the abdomen was the critical test that led to the correct diagnosis. Therapy involved drainage and antibiotics, and was successful in 3 of the 4 patients.

Abscess↗
PubMed1986

Tumoral amyloidosis of bone of beta 2-microglobulin origin in association with long-term hemodialysis: a new type of amyloid disease.

Amyloid lesions of bone are rare and limited almost exclusively to patients with amyloidosis secondary to plasma cell dyscrasias. The present report describes the cases of two patients receiving long-term hemodialysis (nine and 12 years) who had multiple lytic lesions of bone proved by biopsy to contain an unusual type of amyloid. Results of serum protein electrophoreses and immunoelectrophoreses, as well as bone marrow examinations, were normal. In both cases the amyloid displayed characteristic Congo red affinity and birefringence on polarized light microscopy that was inhibited by potassium permanganate treatment of sections prior to staining. Although this staining reaction was described previously exclusively in AA amyloid (i.e., the material associated with classic secondary amyloidosis), immunoperoxidase staining for AA protein in these cases was negative. Transmission electron microscopy revealed the amyloid fibrils to have unusual curvilinear configurations. Immunoperoxidase staining for beta 2-microglobulin (beta 2m) was positive in the amyloid lesions of both patients at the light microscopic level. Ultrastructural immunohistochemical studies for beta 2m, performed in one case, were positive. Both patients had markedly elevated serum beta 2m levels. By Ouchterlony immunodiffusion, purified beta 2m demonstrated partial identity with purified amyloid protein fractions and a serum constituent. Bone lesions composed of amyloid related to beta 2M probably represent a new subgroup of amyloid disease that may be linked to renal failure and long-term hemodialysis.

Aged↗