Noncultivable viruses and neonatal diarrhea: fifteen-month survey in a newborn special care nursery.

During a 15-month period of surveillance, diarrhea developed in 257 of 913 babies (28%) admitted within 2 hours of birth to a special care nursery in Melbourne, Australia. Diarrhea was seasonal, affecting a maximum of 43% of babies admitted during one winter month (July) and a minimum of 13% of babies admitted during one summer month (December). Diarrhea was no more frequent nor more severe in babies of very low birth weight or of very early gestational age. Two noncultivable viruses were located by electron microscopy in feces from babies with or without diarrhea. Excretion of a reovirus-like particle (rotavirus, duovirus, human reovirus-like agent, infantile gastroenteritis virus) was temporally related to diarrheal symptoms. Asymptomatic infection with this virus also occurred. A 28-nm virus-like particle was excreted by some babies, but it could not be implicated on epidemiological grounds in the etiology of the diarrhea. Rotavirus infection may be an important cause of endemic diarrhea in nurseries for the newborn. Infection may be difficult to control or eradicate, since it is often asymptomatic and may be influenced by infection in the community at large.     

Interoception: the inside story--a model for psychosomatic processes

OBJECTIVE: To comprehend psychosomatic processes, it will be necessary to understand the brain's influences on bodily functions and also the body's afferent sensory input to the central nervous system, including the effects of this input on behavior and cognitive functions, especially emotion. The objective of this Presidential Address is to review what is known circa the year 2000 of the processes and mechanisms of visceral sensory psychobiology, often called interoception. METHODS: Over 1000 publications that have appeared since the 19th century were reviewed to prepare this review, including a group that are specifically cited here. RESULTS: Factors and data were reviewed that were identified as germane to understanding interoception. These included definitional issues, historical roots, the neural basis, studies and results in the cardiovascular-respiratory and alimentary-gastrointestinal systems, studies of emotion, and studies in people with mental disorders. Drug and hormone effects, pain, proprioception, and phantom limb or organ factors, and the role of awareness were briefly described. Methodological issues, methods of study including functional imaging, and possible future directions for study were identified. CONCLUSIONS: Understanding the physical basis of psychosomatic processes, including the so-called mind-body problem, will require a detailed understanding the psychobiology of interoception.     

Trial of platelet-derived growth factor antagonist,trapidil, in accelerated nephrotoxic nephritis in the rabbit.

The platelet-derived growth factor (PDGF) antagonist, trapidil, which also blocks the thromboxane and/or PG-endoperoxide receptor and is an inhibitor of thromboxane synthetase, was administered during rabbit accelerated nephrotoxic nephritis; the clinical and histological evolution was studied as well as urinary immunoreactive thromboxane (i-TXB2) and immunoreactive prostaglandin E2 (i-PGE2) excretion. Although the dose we used has been shown to be effective in vivo, and it inhibited the urinary i-TXB2 excretion on days 5 and 10, it neither inhibited the enhanced production of i-TXB2 on day 1, nor prevented the glomerular influx of monocytes on days 5 and 10. All clinical and histological data tend to be worse rather than better in trapidil-treated animals on days 5 and 10.     

Immunohistochemical labeling for the Dpc4 gene product is a specific marker for adenocarcinoma in biopsy specimens of the pancreas and bile duct.

We immunohistochemically labeled 72 biopsy specimens from the extrahepatic biliary tree and pancreas for Dpc4 protein and correlated expression with histologic diagnosis and patient follow-up. Specimens were classified histologically as follows: nonneoplastic, 35; neoplastic, 22; atypical, 15. Loss of expression of Dpc4 protein was identified in 12 specimens; 11 were histologically diagnostic of carcinoma. The 12th specimen was from a patient whose biopsy specimen initially was diagnosed as "atypical," but clinical follow-up revealed adenocarcinoma. Of the 12 atypical biopsy specimens with intact expression for Dpc4, follow-up later revealed that 10 were adenocarcinoma. Loss of expression of Dpc4 protein was never identified in a benign specimen. Immunohistochemical labeling for the Dpc4 gene product is a specific marker of carcinoma in biopsy specimens of the pancreas and extrahepatic bile ducts and is marginally helpful in classifying atypical specimens. The sensitivity for carcinoma is low. This latter finding is not unexpected, because the DPC4 tumor suppressor gene is inactivated in only about half of pancreatic and biliary malignant neoplasms. Importantly, loss of Dpc4 expression has been reported in in situ carcinomas, suggesting that loss of expression should not be equated with invasive carcinoma.     

The differentiation capacity of Clara cells isolated from the lungs of rabbits

The purpose of our studies was to determine the growth and differentiation potential of Clara cells isolated from rabbit lungs. The Clara cell preparations were enriched (80 to 85%) by density gradient-elutriation procedures and then were inoculated into rat tracheas denuded of their own epithelium. These tracheas then were transplanted subcutaneously on the backs of nude mice. For purposes of comparison, other denuded tracheas were inoculated with mixed epithelial cells obtained from rabbit tracheas by enzymatic procedures. Control tracheas were inoculated with cell-free media. At 2, 4, and 14 weeks after transplantation, the tracheal grafts were removed from the recipient nude mice and examined by light and electron microscopy. Tracheal grafts not receiving cell inocula contained no epithelial lining, and the tracheal lumens were filled with loose connective tissue. Tracheas inoculated with 2 X 10(4) mixed tracheal cells showed a columnar, pseudostratified epithelium composed of five cell types: (a) poorly-differentiated cells, (b) ciliated cells, (c) mucous cells, (d) Clara-like cells, and (e) typical basal cells. A very different epithelium was established in tracheas repopulated with Clara cell isolates. This epithelium, at all time points examined, was cuboidal, single layered (never pseudostratified), and lacked basal cells. The tracheal lumens were lined with ciliated and nonciliated cells. The latter showed typical features of mature Clara cells (i.e., electron dense granules and smooth endoplasmic reticulum). At 14 weeks, the same two cell types were present, and often they were located on ridges and furrows of the tracheal walls. Mixed tracheal cells inoculated into denuded tracheas gave rise to a normal-appearing pseudostratified mucociliary epithelium, whereas the Clara cells inoculated under identical conditions gave rise to a low cuboidal epithelium resembling that seen in normal bronchioles. Establishment of these two types of epithelial linings occurred in the presence of the same mesenchymal components. Thus, we conclude that Clara cells have considerable self-renewal capacity, and their differentiation potential appears to be quite narrow.