Abomasal emptying defect in Suffolk sheep.

Twelve Suffolk sheep were examined because of an abomasal emptying problem. Anorexia and weight loss were evident in 11 of the sheep. Ventral abdominal distention was observed in 5 sheep.

Natural transovarial transmission of dengue 4 virus in Aedes aegypti in Trinidad.

The isolation of dengue 4 virus from adult Aedes aegypti, reared from eggs collected in nature, is reported for the first time. From the locality where the isolate was made, 25 pools consisting of 1,848 Ae. aegypti reared from eggs were processed.

Thermodilution curves for diagnosis of ventricular septal defect in cattle.

An indicator dilution method developed for detection of intracardiac shunts and determination of cardiac output in man and domestic animals was evaluated in 4 calves and 1 cow with holosystolic cardiac murmurs. Thermodilution curves recorded from the pulmonary artery and the right ventricle confirmed a left-to-right intracardiac shunt and provided a means for its quantitation. Ventricular septal defect was confirmed in 2 cows, which were euthanatized.

The living skin-equivalent as a structural and immunological model in skin grafting.

The living skin equivalent is a tissue formed when self-assembled collagen fibrils are contracted by fibroblasts. The rate and extent of volume contraction is proportional to the number of cells incorporated into the lattice. The fibroblasts are biochemically active in the lattice, synthesizing collagen and adding it to the matrix.

Acceptance of allogeneic fibroblasts in skin equivalent transplants.

Living skin equivalents (SE) were prepared by combining cultured fibroblasts with a collagen matrix and overlaying this lattice with keratinocytes. SEs prepared using allogeneic female rat fibroblasts or xenogeneic rabbit or human fibroblasts and keratinocytes isogeneic to the graft recipient were transplanted to recipient male rats. Biopsies of some of these SE grafts were examined histologically at intervals ranging from 5 days to 2 months.

Fibroblasts in isogeneic skin equivalents persist for long periods after grafting.

We have fabricated skin equivalents by combining fibroblasts from female Fischer rats with collagen to form a lattice and overlaying the lattice with a suspension of epidermal cells. The epidermal cells attach and form a sheet which differentiates. These skin equivalents were then grafted to male Fischer rats in order to follow the fate of the fibroblasts after implantation.

Structural integration of skin equivalents grafted to Lewis and Sprague-Dawley rats.

Bilayered skin equivalents, composed of a sheet of epidermal cells overlying a collagen lattice populated with fibroblasts, quickly become structurally integrated with the surrounding host skin after grafting to Lewis rats. Three days after transplantation, the skin equivalent lies on a bed of host granulation tissue and is loosely attached to the adjoining host dermis. Blood vessels begin to invade the collagen lattice by 5 days after grafting.

The reconstitution of living skin.

A living-skin equivalent useful as a skin replacement and as a model system for basic studies has been fabricated and tested extensively. It consists of two components: (1) a dermal equivalent made up of fibroblasts in a collagen matrix that is contracted and modified by the resident cells, and (2) an epidermis that develops from keratinocytes "plated" on the dermal equivalent. A multilayered keratinizing epidermis with desmosomes, tonofilaments, and hemidesmosomes forms.

Structural characterization of a rat acinar cell tumor.

A transplantable acinar cell tumor of the rat pancreas has been examined by light and electron microscopy. The tumor cells, though highly cytodifferentiated and characterized by the presence of abundant rough-surfaced endoplasmic reticulum, elements of the Golgi complex, and zymogen granules, undergo mitosis in a manner similar to that seen in the developing pancreas. Cells in the parenchyma of the tumor grow as disarrayed cords and sheets, are randomly oriented with respect to each other, and do not form acinar structures.

Osteochondrosis, degenerative joint disease, and vertebral osteophytosis in middle-aged bulls.

Twenty-five middle-age (65 +/- 18 months) dairy bulls sent to slaughter for nonmedical reasons were evaluated for joint disease in the stifle and the lumbar vertebrae. Fourteen bulls had degenerative joint disease and 3 had osteochondrosis (osteochondritis dissecans) of the distal end of the femur. These lesions predominantly involved the lateral trochlear ridge.

The relative importance of rotavirus and other pathogens in the etiology of gastroenteritis in Trinidadian children.

Over a 2-year period, 300 infants less than 3 years old with gastroenteritis admitted to hospitals in Trinidad were investigated for the presence of certain microorganisms in the feces, along with an equal number of age- and sex-matched controls. Rotavirus was detected in 23% of cases and 1% of controls; Salmonella in 7% of cases and in 1% of controls; Shigella in 4% of cases and in no controls and two serotypes of enteropathogenic E. coli in 7% of cases and in 2% of controls.

Paramphistomum microbothrioides in American bison and domestic beef cattle.

Intestinal paramphistomiosis was diagnosed in a bull and cow with severe diarrhea and weight loss, and subsequent investigation suggested that the infection was transmitted from American bison (Bison bison). The rumen fluke, Paramphistomum microbothrioides, was recovered from the rumen of 3 bison on the farm or origin. Single operculate eggs of P microbothrioides measuring 130 x 69 micrometers were recovered from the feces of the bull, from 9 of 10 bison, and from 3 of 9 other beef cattle.

Regulation of proliferation of fibroblasts of low and high population doubling levels grown in collagen lattices.

While IMR 90 and AG 1519 fibroblasts of low and high population doubling levels grow to confluency when plated on plastic surfaces, they cease to divide within four days when incorporated into collagen lattices. Growth inhibition in the lattices is not due to exhaustion of the medium or isotope, or to contact inhibition; nor is it due to impermeability of the lattice to the materials in the medium. While cells in a lattice arrest in G0, this state is reversible when cells are permitted to leave the lattice and populate a plastic substrate.

Cell surface properties of normal, differentiating, and neoplastic pancreatic acinar cells.

Acinar, centroacinar, and endocrine cells of the adult rat pancreas each exhibit distinctive cell-surface glycoconjugate patterns as detected by binding of a battery of lectin-ferritin conjugates. Acquisition of these unique glycoconjugate patterns appears to be developmentally regulated, as studies on embryonic rat pancreases at days 15, 17, and 19 of gestation indicate. Further, the three cell types appear to arise from a common stem cell(s) with surface glycoconjugate properties similar to those of the adult centroacinar cell.

Development and use of a living skin equivalent.

We have developed a living skin equivalent, which serves as a skin substitute in experimental animals. On application it is rapidly vascularized, it inhibits wound contraction, and it is immunologically tolerated and persists for as long as it is allowed to remain in place. It comes to resemble normal skin, although it lacks secondary derivatives, the cells for which may in time be available for incorporation into the fabricated tissue.

Irreversible photoactivation of a pancreatic secretagogue receptor with cholecystokinin COOH-terminal octapeptides.

The photochemically reactive analog of cholecystokinin octapeptide (CCK-8), 2-nitro-5-azidobenzoyl-Gly-Asp-Tyr-(SO3H)-Met-Gly-Trp-Met-Asp-Phe-NH2 (NAB-Gly-CCK-8), has been used to stimulate irreversibly the receptor for CCK-8 on preparations of dispersed guinea pig pancreatic acini. When continuously present with acini in the dark, NAB-Gly-CCK-8 is a reversible stimulant of secretory protein discharge with an ED50 of 0.4 nM.

Serological evidence of dengue virus activity in children on the Northern Leeward Islands (Netherlands Antilles).

An arbovirus serologic survey of school children on the Northern Leeward Islands (Saba, St. Eustatius and St. Maarten) using haemagglutination inhibition (HI) detected a high proportion of reactors to dengue types 1,2, and 3.

The terminal web. A reevaluation of its structure and function.

The apical cytoplasm of epithelial cells of the small and large intestines has been examined by freeze-etch techniques as well as conventional and high voltage electron microscopy of sectioned material to gain a better understanding of the fine structural organization of the terminal web region. In the small intestine the terminal web exhibits a distinct stratification caused by the association of different sets of filaments with the three members of the junctional complex. Individual filaments of this network are closely associated with the sealing elements of the tight junctions, the surface of the core microfilament bundles, and the intermicrovillar plasma membrane.

Echocardiographic diagnosis of endocarditis in a bull.

A 2-year-old Charolais bull was examined because of lameness that developed after infection of a tail laceration. A systolic murmur was auscultated during the routine physical examination. A diagnosis of endocarditis and polyarthritis secondary to septicemia from the tail lesion was made.