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Biomedical subjects

M Tenner

Publications and source records attributed to M Tenner.

9 recordsLinked to original sources

A microsporidian previously undescribed in humans, infecting enterocytes and macrophages, and associated with diarrhea in an acquired immunodeficiency syndrome patient.

To date, the only microsporidian that has been associated with diarrhea and weight loss in acquired immunodeficiency syndrome patients is the newly identified Enterocytozoon bieneusi. A second species is now described that was associated with intestinal symptoms in a 32-year-old, human immunodeficiency virus- seropositive, Native American male homosexual. Stool studies and routine light microscopy of multiple small intestinal biopsies that showed atrophy with acute and chronic inflammation were without apparent pathogens. Light microscopy of semi-thin plastic sections, cytochemical stains of paraffin sections, and ultrastructural studies revealed extensive microsporidial infection of enterocytes and submucosal macrophages. No other pathogens were identified. Unlike E bieneusi, this microsporidian appeared to develop within septated parasitophorous vacuoles, and lacked polar disks and clear clefts. It most closely resembled, but was distinguishable from, members of the genus Encephalitozoon. Awareness of the microsporidia as potential opportunists in acquired immunodeficiency syndrome patients is increasing the incidence of identification of these organisms.

Adult

Localization of infection by the microsporidian Enterocytozoon bieneusi in the gastrointestinal tract of AIDS patients with diarrhea.

OBJECTIVE: We compared the level of Enterocytozoon bieneusi infection at different sites within the small intestine among patients with AIDS. DESIGN: The level of E. bieneusi infection of each patient biopsy was determined and compared using semi-thin plastic section light microscopy and transmission electron microscopy (TEM). PATIENTS, PARTICIPANTS: Nine subjects with chronic diarrhea who had endoscopic biopsies of either proximal (bulb) or distal (fourth portion) duodenum plus proximal jejunum (just past ligament of Treitz), either simultaneously or within a few months of each other were studied. All patients had TEM-confirmed diagnoses of E. bieneusi intestinal microsporidiosis. RESULTS: The intensity of infection was always greater in biopsies taken from the patients' jejunum compared with those taken from the duodenal bulb. In one patient, the duodenal bulb biopsy was negative while the jejunal biopsy, taken at the same time, was positive. The distal duodenum was usually, but not always, equal to the jejunum in terms of parasite burden. Esophageal, gastric, and colorectal biopsies from these and other patients were negative for E. bieneusi. CONCLUSIONS: For the diagnosis of E. bieneusi to evaluate chronic diarrhea in AIDS patients, upper intestinal endoscopy biopsies should be taken at the most distal site possible.

Acquired Immunodeficiency Syndrome

Carcinoma of choroid plexus in a premature infant.

A histologically proven case of choroid plexus carcinoma in a 5-week-old infant is presented. Computed tomography showed invasion through the ventricular wall, suggesting its malignant nature.

Adenocarcinoma, Papillary

The postoperative myelogram. Radiographic evaluation of arachnoiditis and dural/arachnoidal tears.

Either arachnoriditis or dural/arachnoidal tears may cause symptoms in the postoperative spinal patient. Surgery and myelography as causes of arachnoiditis are discussed. Intradural arachnoid cyst formation and intramedullary cavitation may present as unusual sequelae of arachnoiditis. Extra-dural cysts and cerebrospinal fluid fistulas resulting from dural/arachnoidal tears are unusual postoperative complications presenting striking myelographic features. Their mechanisms of formation, clinical significance, and radiographic features are discussed.

Animals

Hyperdipsia associated with hypothalamic-midbrain hemorrhage.

A case of diencephalic-midbrain hemorrhage presenting with excessive thirst, coma, and death is discussed. Some diencephalic dysfunction syndromes are reviewed, as well as their physiological basis. Thirst and drinking behavior can provide a valuable localizing symptom and sign in clinical-pathological correlations.

Adult

Orbital neurofibromatosis: involvement of the orbital floor.

Neurofibromatosis has been reported to involve the eye and orbit by causing irregularities of the sphenoid and other facial bones and enlargement of the foramina. To our knowledge, abnormalities of the orbital floor, however, have not been attributed to this disease in the literature until now. Two patients with neurofibromatosis had orbital floor involvement. Multiple neurofibromas eroding the orbital floor threatened vision in one patient. The other case, seen after trauma, had a condition simulating that of a blow-out fracture. Diagnostic workup with adequate roentgenography, especially tomography, helped to establish the diagnosis. We believe this is of importance in modifying the surgical approach, obviating the need for surgical intervention at times.

Female

Non-filling of the subependymal veins of the lateral ventricles.

Four cases of non-filling of the subependymal veins of the lateral ventricles and internal cerebral vein at carotid angiography are reported. The patients were all children ranging in age from 4 months to 2 years and had a variety of neurologic conditions. Several hypotheses are suggested as to the possible pathogenesis of these findings.

Angiomatosis

The spectrum of growing skull fracture in children.

The genesis and complications of the growing skull fracture in children is discussed. Four patients are presented to illustrate the common and uncommon features of growing skull fractures. The need for complete radiological evaluation as well as the timing of follow-up examinations is stressed.

Brain Diseases