Experimental models of ecological niches for African swine fever virus.

In this study, we investigated the possible biological factors affecting the survival of the African swine fever virus (ASFV) in the environment and their potential to influence the ecology of the ASFV. Specifically, we tested the survival and replication of ASFV in four phylogenetically distinct organisms: Paramecium caudatum, Dendrobaena alpine, Aedes aegypti andXeropicta derbentina using qReal-Time PCR and hemadsorbtion analysis. Levels of ASFV in earthworms (Dendrobaena alpina) and soil declined at similar rates, suggesting that earthworms likely have no influence on the ecology of the ASFV. Ciliates (Paramecium caudatum) significantly increase the rate of ASFV disappearance from the aquatic environment, probably using the virus as a food source. Mosquitoes (Aedes aegypti) do not provide significant support for the persistence of ASF virus in the environment, with no evidence for transmission to their offspring or pigs that ingested mosquitoes. ASFV persisted for much longer in air-breathing land snails (Xeropicta derbentina) than in the soil. Moreover, transcription of viral genes was maintained within the snail, although the question of full-fledged viral replication is still open. In addition, the active movements of snails suggests that they could play a role in the spread of the virus. The virus is likely to be localized in the intestines of snails as it is regularly excreted from their feces. These results highlight the importance of investigating invertebrates for understanding ASFV surviving, spreading and transmission in natural populations with zoonotic transmission potential.

Comparison of patients with central sleep apnea. With and without Cheyne-Stokes respiration.

This study was designed to determine the impact of central sleep apnea with or without Cheyne-Stokes respiration (CSR) on morbidity and mortality. Central sleep apnea was found in 77 male general medical ward in-patients. Cheyne-Stokes respiration was found in 49 of the 77 men; in 15 men, CSR was severe, ie, > or = 25 percent of the night spent in CSR, in 34 men CSR was mild (1 to 25 percent CSR). Twenty-eight men had central sleep apnea but no CSR. An additional 31 patients had no sleep apnea and no CSR. The patients with severe CSR had more central apneas, more, but shorter desaturations, more awakenings and more wake time during the night, but spent more time in bed than those with no CSR or no apnea. Radiographic evidence was consistent with an association of CSR and heart failure. In addition, patients with severe CSR were at almost twice the risk of dying compared with those with no apnea and had a shorter survival time. Nevertheless, we could not confirm that CSR was an independent predictor of elevated mortality risk, implying that some other factors specific to severe CSR predispose these patients to shorter survival time.

Scanning acoustic microscopy of neoplastic and inflammatory cutaneous tissue specimens.

Acoustic microscopy utilizes high frequency ultrasound to generate microscopic images. The current study was designed to examine representative disorders of the skin by use of a reflective scanning acoustic microscope (R-SAM), and to determine whether the obtainable resolution was sufficient to render a microscopic diagnosis. An Olympus UH3 Scanning Acoustic Microscope was utilized with lenses producing burst wave frequencies at 600 and 800 MHz (600 and 800 million cylces/sec). Cutaneous tissue specimens representing 12 different neoplastic and inflammatory disorders were examined. Acoustic images of unstained sections were compared with conventional light microscopic study of sections stained with hematoxylin-eosin. In most neoplasms examined, it was possible to make a specific diagnosis primarily from low magnification pattern analysis. Although individual cells could be visualized, cytologic atypia was poorly defined. In the inflammatory disorders, a specific diagnosis was possible in all but bullous pemphigoid and lichen planus, because the composition of the inflammatory infiltrate was difficult to determine. The advantages of the R-SAM include the capability of producing an acoustic profile of the tissue and the future possibility of in situ diagnosis.

Neurologic complications of the epidermal nevus syndrome.

The epidermal nevus syndrome is a neurocutaneous disorder characterized by distinctive skin lesions and often serious somatic and central nervous system (CNS) abnormalities. We observed four cases of this disorder with epidermal nevi and neurologic manifestations, including mental retardation, seizures, ophthalmologic abnormalities, intracranial aneurysm, and porencephalic cyst. A review of 60 reported cases of the epidermal syndrome and our experience suggest that CNS complications are more likely to be associated with epidermal nevi on the head and that the CNS abnormalities are most often ipsilateral to the skin lesion.

Loss of epidermal Langerhans' cells and endothelial cell HLA-DR antigens in the skin in progressive systemic sclerosis.

Skin biopsies from the volar aspect of the forearm were studied in 26 patients with progressive systemic sclerosis (PSS) (16 diffuse, 10 CREST) and 4 controls using monoclonal antibodies against Langerhans' cells, T lymphocytes, macrophages, B lymphocytes, NK/K cells and HLA-DR antigen(s). Langerhans' cells were reduced or absent (anti-T6, anti-HLA-DR) in 19 of 20 clinically involved and in all 6 uninvolved PSS skin biopsies. Electron microscopic studies of 3 PSS patients indicated a reduction in the number of Langerhans' cells, with normal morphology of the remaining. HLA-DR antigen(s) on dermal endothelial cells were absent or reduced in 8 of 20 involved and 5 of 6 uninvolved PSS skin biopsies, but were present on the surface of dermal mononuclear cells presumably representing activated T lymphocytes. Increased numbers of dermal macrophages were found in 19% of PSS biopsies compared with controls. Absence of Langerhans' cells appears to represent the most widespread immunopathological feature of PSS. It is also associated with absent endothelial HLA DR surface antigens and activated T lymphocytes within the dermis.

Cell kinetic basis for pathophysiology of psoriasis.

Studies on the cell proliferation kinetics of psoriatic epidermal cells are presented and the results compared to similar studies for normal epidermis. The short 36-h duration of the psoriatic cell cycle (Tc) is confirmed with the first double-peaked fraction of labeled mitoses (FLM) curve in human subjects. The growth fraction of psoriasis using two experimental techniques approximates 100% within 36 h, confirming the rapid Tc found by the FLM method. The cell kinetic basis for the pathophysiology of psoriasis consists of at least 3 proliferative abnormalities in comparison to normal epidermis. By far the largest alteration is the shortening of the Tc from 311 to 36 h. There is also a doubling of the proliferative cell population in psoriasis from 27,000 to 52,000 cells/mm and an increase in the growth fraction from 60% to 100%. As a consequence of these abnormalities the psoriatic epidermis produces 35,000 cells/day from a proliferative compartment of 52,000 cells/mm2 surface area. This is a 28-fold greater production of cells than the 1,246 cells/day produced in normal epidermis. The biochemical or control factors leading to these kinetic differences continue to remain elusive.

Stimulation of WI-38 cell cycle transit: effect of serum concentration and cell density.

Flow microfluorometry has been used to characterize the effects of serum concentration and cell density on the initiation of cell cycle transit of stationary phase (G0) human diploid fibroblasts (strain WI-38). The concentration of serum used to stimulate these cultures had no effect on the time cells began appearing in S (the DNA synthetic period), nor on the synchrony with which they moved around the cell cycle. However, as the serum concentration increased, the fraction of the stationary phase population released from G0 increased. Cell density modulated the ability of serum to stimulate cell cycle traverse. For example, at a cell density of 1.81 X 10(4) cells/cm2, 78% of the population was sensitive to serum stimulation; whereas, when the density was increased to 7.25 X 10(4) cells/cm2, only 27% of the population could be stimulated. This effect of cell density on the serum response is not simply the result of changing the ratio of serum concentration to cell density, but appears to reflect a true modulation of the population's sensitivity to serum stimulation. These results are consistent with the interpretation that the primary action of serum is to determine the transition of cells from a non-cycling G0 state to a cycling state and that cell density determines the proportion of the population capable of undergoing this transition.