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Escherichia coli, which produce heat-stable enterotoxin (STa), cause intestinal fluid secretion as a mechanism of diarrhea. To determine the factors that modulate the intestinal secretory response, we first compared the time course of the STa-induced secretion in ligated in situ loops of rat jejunum and ileum. We found that the jejunal secretory response was brief (less than or equal to 30 min) while the ileal response to STa was sustained (greater than or equal to 3 h). We then compared the modification of purified STa that occurred in jejunum and ileum and found a close correlation between the continued presence of unmodified, authentic STa and continued fluid secretion in the ligated-loop model. At both sites alteration of STa was demonstrated by high-performance liquid chromatography profile and brush-border membrane binding activity. However, in the jejunum, the modification of STa was qualitatively different and quantitatively much greater. We conclude that the degree to which STa is inactivated or removed from the intestine correlates with the secretory response observed. Inactivation of STa may be a mechanism by which the host limits its secretory response.

A 12-year-old girl was admitted to the hospital for evaluation of an abdominal mass. A preoperative computed tomography scan showed a large tumor in the pelvis. The serum alpha-fetoprotein level was 2,170,000 ng/ml. A 3000-g left ovarian neoplasm was resected. It was encapsulated and showed focal microcystic degeneration, necrosis, and hemorrhage. Microscopically, it was composed of gland-like spaces containing mucin-positive material and surrounded by scant fibrovascular tissue. The epithelial cells were low columnar with immature oval, basophilic nuclei. Immunoperoxidase staining for alpha-fetoprotein and alpha1-antitrypsin were positive. Enzyme histochemistry was negative for alkaline phosphatase and positive for alpha-naphthyl acetate esterase. Electron microscopy, including freeze-fracture analysis, showed desmosomes and tight junctions. No gap junctions were identified. Actin filaments, glycogen, and microvilli were abundant. This is the first case of an ovarian endodermal sinus tumor with exclusive enteric differentiation.

Decreased perfusion in the frontal lobes of patients with chronic schizophrenia has been reported by multiple observes using a variety of techniques. Other observers have been unable to confirm this finding using similar techniques. In this study quantitative single photon emission computed tomography brain imaging was performed using p,5n [123I]IMP in five normal subjects and ten chronically medicated patients with schizophrenia. The acquisition data were preprocessed with an image dependent Metz filter and reconstructed using a ramp filtered back projection technique. The uptake in each of 50 regions of interest in each subject was normalized to the uptake in the cerebellum. There were no significant confirmed differences in the comparable ratios of normal subjects and patients with schizophrenia even at the p = 0.15 level. "Hypofrontality" was not observed.

The anatomic pathology services of 434 health care institutions in California were surveyed about their use of computers. Of 200 (46%) respondents, 106 (53%) did not use computers at all. Of 94 (47%) respondents who used computers, 77 (82%) used them for administrative purposes; 74 (79%), for any routine processing of surgical specimens; 43 (45%), for processing surgical specimens other than word processing (eg, database); 52 (55%), for processing cytology specimens; and 60 (63%), for processing autopsy specimens (including word processing). Computer use was slightly greater with higher work loads. Among nonusers, on a scale of 1 to 5 the average interest in using computers was 3.5 for surgical pathology data, 3.4 for cytology data, and 2.8 for autopsy data. The interest rate also increased with work load, and was nearly 4 for laboratories with greater than 4000 surgical or cytology cases per year. The average interest in controlling and/or making decisions about computer hardware and software was 3.9 for hardware and 4 for software. Reasons for low computer use in anatomic pathology despite interest in utilization are discussed, including the limited selection of affordable commercial software for anatomic pathology and difficulties of in-house software development.

Fine-needle aspiration biopsy smears are useful in the workup of patients with abscesses and inflammatory masses. We report 37 cases classified into three groups: group I, in which a causative organism was seen on the smear; group II, in which a causative organism was cultured from a smear where organisms were not seen microscopically, and group III, in which the organism was not seen or cultured, but the smear findings were useful in determining further workup.

A patient suffering baclofen overdose successfully treated with atropine is reported. Three hours after admission for ingestion of at least 300 mg baclofen as a single dose, the patient became comatose and subsequently bradycardic, hypotensive, and hypothermic. A prompt increase in heart rate and blood pressure followed administration of 1 mg of atropine sulfate. Atropine appears to be useful in treating cases of baclofen overdose complicated by bradycardia and hypotension.

Escherichia coli heat-stable enterotoxin (ST) binds to receptors on rat intestinal cells and brush border membranes (BBM). We devised experiments to examine the reversibility of ST binding. We found that both 125I-labeled ST and native ST were spontaneously dissociable from the BBM receptor. Radiolabeled ST bound to BBM was also dissociated by the addition of avid goat anti-ST antiserum. Furthermore, using a computer program for analysis of ligand binding, we calculated an apparent Ka of 10(8) liters/mol from competitive inhibition and saturation-binding data. This is significantly lower than the value previously reported by others. Our findings, of a lower Ka and a reversible ST-binding process, suggest that a therapeutic strategy of removing bound ST from its receptor or competing with the enterocyte receptor for unbound ST might be successful in terminating ST-induced secretion.

The effect of the cyclopentenyl adenosine analog neplanocin A (NPC) on cell growth and differentiation was examined in the human promyelocytic leukemia cell line HL-60. Continuous exposure of HL-60 cells to 0.1-3.3 microM NPC resulted in a progressive reduction in cell growth which was accompanied by an increase in differentiation to cells with a myelocyte and neutrophil morphology. The latter effect was expressed as an increase in the capacity of cells to reduce nitro blue tetrazolium and reached a level of 40% of the total cell population. Preceding the phenotypic changes was the preferential inhibition of RNA and DNA methylation in comparison to inhibition of their synthesis which coincided with the formation of a metabolite of NPC with the chromatographic characteristics of S-adenosyl-L-methionine (AdoMet). In addition, c-myc mRNA expression, which is amplified in HL-60 cells, was markedly reduced following NPC treatment. These results indicate that NPC is an effective inhibitor of RNA and DNA methylation resulting from its conversion to an analog of AdoMet, and that these effects appear to be responsible for reduced c-myc RNA expression and the induction of myeloid differentiation in this cell line.