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Biomedical subjects

J T McMahon

Publications and source records attributed to J T McMahon.

17 recordsLinked to original sources
PubMed1992

Adrenal carcinosarcoma presenting in a woman with clinical signs of virilization. A case report with immunohistochemical and ultrastructural findings.

An adrenal carcinosarcoma is reported in a 29-year-old female presenting with clinical signs of virilization. This is the first reported case of a functioning adrenal carcinosarcoma in the English language literature. The tumor measured 12.5 cm in greatest dimension, weighed 610 g, and consisted of large areas of typical adrenal cortical carcinoma that was, however, interspersed with multiple foci of sarcoma. Rhabdomyosarcomatous elements were identified and confirmed both immunohistochemically and ultrastructurally. After radical resection, the patient received adjuvant mitotane therapy but developed rapid local and metastatic recurrence. Systemic chemotherapy was unsuccessful, and the patient died 8 months after surgery.

Adrenal Cortex Neoplasms↗
PubMed1992

Bubble hair.

An unusual hair dystrophy was studied by means of light and electron microscopy. Hair fibers demonstrated a boomerang deformity containing small and large "bubbles". Electron microscopy revealed a loss of cortical cells and medulla at these sites. Cross-section images showed either a single large cavity or a reticulated, "swiss cheese-like" loss of cells. These two cases represent the second and third reported cases of bubble hair deformity. We present the second light and electron microscopic study of this disorder, including new electron microscopic findings. The cause of bubble hair deformity remains obscure. The involved tufts of wiry hair resolved with gentle hair care. This suggests that trauma to the hair shaft may play a role. It is likely that additional cases of bubble hair remain unrecognized. Investigation of other patients with localized tufts of wiry hair is likely to reveal additional cases.

Adult↗
PubMed1992

Pseudo-gamma heavy chain (IgG4 lambda) deposition disease.

Two patients with Ig deposition disease presented with acute renal failure, moderate proteinuria, and hematuria. A plasmacytoid lymphocytic infiltrate was identified in bone marrow that produced IgG4 lambda and free lambda light chains. One patient developed an anaplastic plasmacytoma (secreting only lambda light chains) 1 yr after renal biopsy. Renal biopsy in both patients demonstrated a nodular intercapillary glomerulopathy and electron dense granular deposits, associated with a linear pattern of IgG4 heavy chain deposition in vascular, tubular, and glomerular basement membranes (VBM, TBM, and GBM). In one patient this entrapped IgG4 was unassociated with detectable kappa or lambda light chains. In the second patient, lambda light chains (1+) were detected only in the GBM, but IgG4 (4+) was identified in GBM/TBM. Neither circulating (peripheral blood and bone marrow serum) nor cellular free gamma chains were present. We propose the term "pseudo-gamma heavy chain deposition disease" for the process.

Aged↗
PubMed1991

Sclerosing vasculopathy of the central nervous system in nonelderly demented patients.

Three nonelderly patients without hypertension whose clinical and radiologic features otherwise resembled Binswanger's subcortical arteriosclerotic encephalopathy underwent biopsy of the hyperintense periventricular lesions seen on magnetic resonance imaging. The pathologic findings of the periventricular lesions consisted of gliosis with mild rarefaction and edema of the white matter. All patients had a sclerosing vasculopathy of unknown cause, which involved numerous small vessels within the periventricular lesions. The vessels stained negatively for amyloid, amyloid precursors, desmin, vimentin, keratin, immunoglobulin, and complement. On electron microscopy, small arteries, arterioles, venules, and capillaries were characterized by swollen astrocytic foot processes surrounding the vessels; dense, perivascular collagen packing; crystalline arrays of filaments within basement membrane; giant lipid-laden lysosomes within perivascular cells; and narrowing of the vascular lumina. Similar changes were not seen in a control group of 19 patients. The pathologic features of the vessels in these cases are distinct from the vasculopathy associated with Binswanger's subcortical arteriosclerotic encephalopathy. We suggest that a spectrum of vasculopathies may be associated with dementia and periventricular hyperintense lesions on magnetic resonance imaging.

Adult↗
PubMed1991

Mineral-associated hepatic injury: a report of seven cases with X-ray microanalysis.

The patterns of hepatic injury associated with various minerals were studied in seven patients. The subjects included one patient who was a sandblaster (silica by inhalation), one patient who was a dental laboratory technician (silica and chromium-cobalt alloy by inhalation), one patient with inhalational talcum powder abuse, and four chronic intravenous (IV) drug abusers (talc by IV injection). In all cases, the liver was examined by light and polarizing microscopy, and by scanning electron microscopy with energy-dispersive x-ray microanalysis. In the two patients with silica exposure, silica-containing sclerohyaline nodules were diffusely present in portal tracts and lobules. Both chromium-cobalt alloy and silica were present in the dental technician. In contrast, in all cases of talc exposure, aggregates of talc-laden macrophages were present in portal and centrilobular areas. Three IV drug abusers and the talcum powder abuser had histologic evidence of chronic hepatitis, most probably of viral etiology. We conclude that mineral type plays an important role in the pathogenesis and fibrogenesis of hepatic lesions. Compared with silica, talc primarily elicits a macrophage response without granuloma formation or fibrosis. Hepatic silicosis is a rare complication in dental laboratory technicians, and chromium-cobalt alloy may contribute to hepatic injury and fibrosis in this setting.

Adult↗
PubMed1991

Endoluminal catheter-assisted transcervical US of the human embryo. Work in progress.

To enhance visualization of anatomic structures of the human embryo, the authors used a commercially available catheter-based ultrasound (US) transducer (12.5 MHz) introduced through the cervix and into the endometrial cavity of seven women about to undergo voluntary termination of first-trimester pregnancy. The authors term this technique endoluminal catheter-assisted transcervical (ELCAT) sonography. In none of the patients did the US catheter rupture the fluid-filled chorionic/amniotic cavity. The duration of pregnancy ranged from 5.2 to 10.0 menstrual weeks. The most prominent anatomic structures visualized were the heart and neural tube. As an investigational technique, ELCAT US can be used to image anatomic structures of the developing human embryo.

Catheterization↗
PubMed1991

Corneal microsporidiosis in a patient with AIDS.

Microsporidia are obligate intracellular protozoan parasites that are becoming increasingly recognized as opportunistic pathogens in patients with AIDS. They have been associated with enteritis, hepatitis, and peritonitis and recently keratoconjunctivitis. Gram stain demonstrates the presence of these organisms on light microscopic sections. The specific diagnostic features that distinguish microsporidia from other small nonspore-forming organisms are best demonstrated by electron microscopy, which is also used to characterize the members of Microsporea. In this study, salient histopathologic features of microsporidia in corneal epithelium obtained from an HIV-seropositive individual who developed AIDS are illustrated and discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Hydroxyapatite-coated femoral stems. Histological analysis of components retrieved at autopsy.

Plasma-sprayed coating of hydroxyapatite are biocompatible and, because of their osteoconductive properties, may contribute to the early fixation of total joint prostheses. To evaluate this interface, we histologically analyzed five hydroxyapatite-coated femoral stems which, along with the surrounding bone, were retrieved from three humans at autopsy. The five femoral components had been in situ for a mean duration of twelve months (range, almost five to twenty-five months) and had been inserted for osteonecrosis (two), osteoarthrosis (two), and as an uncermented revision for failure of a cemented stem. The three patients had had a good or excellent clinical result and had died of causes unrelated to the joint arthroplasty. A coating of hydroxyapatite was identified on each stem. There was a variable amount of apposition of bone (32 to 78 per cent of available surface per section). The deposition of bone was most prominent on the surface of the prosthesis that was close to the endosteal surface of the bone, especially in areas that are predicted by Wolff's law (anterior and medial aspects of the implant, and at lateral-oblique corners). There were occasional foci of bone-remodeling around the implant, including osteoclast-mediated removal of the coating of hydroxyapatite along with adjacent bone. Occasional particles of ceramic were present within macrophages in the adjacent bone marrow. Other areas showed formation of new bone with a few areas of bone directly against the metal substrate. The over-all histological features suggest mechanically stable implants with bone-remodeling at the surface of the bone-implant interface.

Adult↗
PubMed1991

Infectious crystalline keratopathy occurring in an eye subsequent to glaucoma filtering surgery with postoperative subconjunctival 5-fluorouracil.

We present a case of infectious crystalline keratopathy occurring after 5-fluorouracil filtering surgery. The patient had discrete, branching, white crystalline lesions in the anterior corneal stroma. Cultures grew Streptococcus viridans, and gram-positive cocci were demonstrated in corneal tissue biopsy specimens. Toxic and immunosuppressive properties of 5-fluorouracil may have participated in the pathogenesis of the infectious crystalline keratitis.

Chronic Disease↗
PubMed1990

Characterization of adult human astrocytes derived from explant culture.

Four different human astrocytic cell lines established from either epilepsy surgical specimens or cerebral white matter obtained during thalamotomy for tremor in a patient with multiple sclerosis were characterized using morphologic analysis, ultrastructural attributes, growth characteristics, and immunocytochemical analysis. Immunocytochemical characterization of cultures indicated a mean of 84% of cells contained cytoplasmic glial fibrillary acidic protein (GFAP): to confirm that GFAP(+) cells also proliferated, bromo-deoxyuridine (BrdU) uptake was measured in cell line. Our method of simplified explant culture allows establishment of astrocytic cell lines from a variety of pathologic substrates using limited amounts of human material.

Adult↗
PubMed1990

A severe fibrotic reaction after cosmetic liquid silicone injection. A case report.

A case of a severe, locally aggressive fibroblastic reaction to cosmetic silicone injection involving the orbital cone and anterior cranial base is presented. Included is a brief history and description of silicone injection and its complications. Though many facts remain to be discovered, speculation into the possible pathogenesis, with a review of the literature, shows that while silicone continues to be a useful tool for the plastic surgeon, an awareness of the risks, as well as a search for clues to avoid complications, must continue before further liberal use of this material is encouraged.

Facial Bones↗
PubMed1990

Hepatic giant cell carcinoma. An ultrastructural and immunohistochemical study.

Hepatocellular carcinoma with osteoclast-like giant cells (hepatic giant cell carcinoma [HGCC]) is a rare entity, with only three cases reported. The tumor is histologically similar to giant cell tumor (GCT) of bone, and the origin of the multinucleated giant cells and mononuclear stromal cells has not been determined. The purpose of this report is to present a case of this rare tumor and compare its ultrastructural and immunohistochemical features with those of a conventional GCT of bone. Histologically, the HGCC consists of sheets of osteoclast-like giant cells with a background of mononuclear cells. The giant cells lack the pleomorphism seen in hepatocellular carcinomas with anaplastic giant cells. At the light microscopic level, most of this tumor was nearly identical to a GCT of bone, but several microscopic fields (less than 5% of the tumor) had the histologic appearance of a "usual" hepatocellular carcinoma. The hepatic tumor was negative for HAM 56, epithelial cytokeratins, muramidase, and alpha-1-antitrypsin, with only focal positivity for chymotrypsin in mononuclear and giant cells. The GCT was strongly positive for alpha-1-antitrypsin and chymotrypsin in both the mononuclear and giant cells and showed focal, weak staining for AE1 and AE3 in the mononuclear stromal cells. Ultrastructurally, both mononuclear and giant cells of the HGCC showed features typical of hepatocellular carcinoma. Although the patient presented in this report died, the pattern of growth was different from most hepatocellular carcinomas. The overall histologic features of this tumor are distinctive and appear to justify separating this variant from other types of hepatocellular carcinoma.

Adult↗
PubMed1990

Hibiclens keratopathy. A clinicopathologic case report.

A 39-year-old woman developed a painful, red eye immediately following oral surgery associated with preoperative preparation of her face with the antiseptic, Hibiclens. Epithelial and stromal edema was observed 2 weeks after surgery and progressed to diffuse bullous keratopathy. This led to penetrating keratoplasty 10 months later. Light and electron microscopic findings of the cornea included epithelial edema with bullous changes, marked loss of keratocytes, a thickened Descemet's membrane, and an attenuated, disrupted endothelial cell layer. These findings demonstrate the corneal damage that may occur following ocular exposure to Hibiclens.

Adult↗
PubMed1979

Rapid separation of mouse T and B lymphocytes using wheat germ agglutinin.

A separation procedure has been developed for mouse splenic T and B lymphocytes which is based on their differential agglutination by wheat germ agglutinin (WGA). In the presence of 50-100 micrograms/ml of WGA, multicellular aggregates are formed which are enriched in B cells. These aggregates can be separated from monodisperse T cells by gravity sedimentation and subsequently dissociated into single cells by treatment with N-acetylglucosamine (NAG). Immunocytochemical analyses and mitogenic assays indicate approximately 10-15% cross contamination of the resultant B and T cell fractions. The separation procedure is not only convenient and rapid but also allows the simultaneous recovery of viable T and B cells from the same spleen preparation.

Animals↗
PubMed1977

A comparative analysis of the relationship between organizational climate and job satisfaction of medical technologists.

This study examines the quality of the total workplace enviroment (organizational climate) as a correlate of six dimensions of job satisfaction for a sample of 344 medical technologists. The main focus is upon comparisons of administrators versus nonadministrators, hospital laboratory personnel versus nonhospital laboratory personnel, and men versus women. Various dimensions or organizational climate were found to be important correlates of job satisfaction, and similarities and differences between the units of analysis are noted. Also discussed are the implications for the managers of medical technologists.

Job Satisfaction↗
PubMed1977

Individual need satisfaction, organizational practices, and job satisfaction among laboratory professionals.

This study examines the role of 1) personal job-related needs and 2) certain organizational characteristics in affecting overall job satisfaction for a sample of 259 laboratory professionals, primarily medical technologists. Specific individual needs and specific organizational characteristics were found to be related to three measures of overall job satisfaction. Additional comparisons were made for administrators versus non-administrators and for differences associated with different sized organizations. Implications for the managers of medical technologists and other laboratory professionals are discussed.

Administrative Personnel↗