A study of the neutralization of rhinoviruses by means of a plaque-reduction test.
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Antibodies↗
Biomedical subjects
M Fiala
Publications and source records attributed to M Fiala.
Plaque formation by 55 rhinovirus serotypes.
Plaque production by 55 rhinoviruses in several lines of HeLa cells is reported. Forty-nine types produced macroscopic plaques under the conditions described previously employing 30 mM MgCl(2) and 30 mug/ml of DEAE-dextran in overlay and M HeLa cells. Basically three kinds of plaques were observed: clear large and intermediate sized plaques and small turbid plaques. Five rhinoviruses produced plaques only in a sensitive clonal line isolated from the M HeLa line. Rhinovirus type 4 produced plaques after the pretreatment of cells with actinomycin D. Enhancement of plaque formation by MgCl(2) has been demonstrated to date with 17 rhinoviruses. Some rhinoviruses were enhanced either by DEAE-dextran or by dextran sulfate in the overlay. No inhibitors were found in any of 10 bovine sera tested. Rhinovirus type 2 was visualized inside HeLa cells by electron microscopy and there appeared to be a very high ratio of physical particles per infectious unit of virus.
Culture Media↗
Effect of magnesium on replication of rhinovirus HGP.
It is known that plaque formation by some rhinoviruses is greatly enhanced by increasing the concentration of MgCl(2). The mechanism of this action was studied by investigating the effects of MgCl(2) on rhinovirus HGP adsorption, growth, clumping, thermal stability, and cell susceptibility to viral cytopathic effect. The latent period was at most 7 hr, whether virus was propagated in cells maintained in 0.8 or 30 mm MgCl(2), but virus release was 8- to 310-fold greater in the presence of 30mm MgCl(2), depending on initial multiplicity. Intracellular virus content appeared unaffected by Mg(++) and reached maximal yield (plateau phase) at about 10 hr. Viral adsorption was increased when cells were maintained in 30mm Mg(++). It is likely that the two effects of magnesium, enhanced adsorption and increased virus release, both contribute to enhancement of plaque formation.
Adsorption↗
Enhancement of rhinovirus plaque formation in human heteroploid cell cultures by magnesium and calcium.
Fiala, Milan (University of Washington, Seattle), and George E. Kenny. Enhancement of rhinovirus plaque formation in human heteroploid cell cultures by magnesium and calcium. J. Bacteriol. 92:1710-1715. 1966.-A reproducible macroplaque assay for six M and three H strains of rhinoviruses has been developed in several human heteroploid cell lines. Plaques were produced only with suitable solidifying agents: purified agar (Ionagar, Agarose) or methylcellulose. Plaque development was greatly enhanced by increasing Mg(+2) to 30 to 40 mm. Diethylaminoethyl (DEAE) dextran also increased plaque sizes, and the effects of Mg(+2) and DEAE dextran were additive. In addition, Ca(+2) substituted for Mg(+2). The suitability of human heteroploid cell lines for rhinovirus plaque assay varied greatly, ranging from insensitivity through partial to complete sensitivity. This assay was six to seven times more sensitive than an end point tube assay. These results indicate that potentiation of plaque formation by Mg(+2) known for some enteroviruses can also be extended to the rhinovirus group of picornaviruses.
Calcium↗
Human immunodeficiency virus type 1 antigenaemia is enhanced in patients with disseminated cytomegalovirus infection and deficient T lymphocytes.
We have studied 61 patients with the acquired immunodeficiency syndrome (AIDS) regarding the relationships between disseminated cytomegalovirus (CMV) infection with CMV retinitis, HIV1 antigenaemia and CD4+ and CD8+ T-cell deficiency. HIV1 p24 antigenaemia was present in all patients with CMV retinitis (at a high concentration), but in only 28% of patients without retinitis (at a low concentration). Compared to patients without retinitis, those patients who developed retinitis had lower CD4+ and CD8+ prior to and during AIDS. CMV may contribute to deficiencies of T lymphocytes in patients with AIDS.
Acquired Immunodeficiency Syndrome↗
Role of CD8+ in late opportunistic infections of patients with AIDS.
We studied the relationship of CD4+ and CD8+ depletion to initial and late opportunistic infections in 62 patients with AIDS. The mean interval between initial and late infections was 12.2 months. Geometric mean (and 95% confidence intervals) of T-cell counts at the diagnosis of each infection were: (Pneumocystis carinii pneumonia) CD4+ 0.051 (0.044-0.058) x 10(9)/l, CD8+ 0.561 (0.476-0.646) x 10(9)/l; (cytomegalovirus retinitis) CD4+ 0.025 (0.019-0.031) x 10(9)/l, CD8+ 0.333 (0.183-0.483) x 10(9)/l. Mycobacterium avium-intracellulare bacteraemia closely followed cytomegalovirus dissemination. Most patients were free from late opportunistic infections caused by disseminated cytomegalovirus and M. avium-intracellulare until CD8+ declined below 0.500 x 10(9)/l. Zidovudine improved CD4+, but less so CD8+, and similarly enhanced the survival of patients treated in 1985-1990 and 1991.
AIDS-Related Opportunistic Infections↗
Responses of neurologic complications of AIDS to 3'-azido-3'-deoxythymidine and 9-(1,3-dihydroxy-2-propoxymethyl) guanine. I. Clinical features.
Fourteen patients with AIDS were treated for 23 neurologic complications: four episodes of acute meningoencephalitis; eight episodes of subacute encephalopathy; two cases of progressive multifocal leukoencephalopathy; and nine cases of polyneuropathy. Nine patients were treated with 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG), one with 3'-azido-3'-deoxythymidine (AZT), and four initially with DHPG directed against cytomegalovirus (CMV) retinitis or encephalitis and subsequently with AZT against human immunodeficiency virus (HIV) encephalopathy. CMV retinitis was a helpful clinical observation indicating neurologic involvement. DHPG produced improvement in two of three cases of acute meningoencephalitis but was ineffective in cases of subacute encephalopathy or neuropathy. AZT therapy resulted in resolution in both of the two treated cases of acute confusional state and in two of the four treated cases of polyradiculoneuropathy with paraparesis but was ineffective in the late stage of subacute encephalopathy. These results suggest that CMV is important in some cases of acute meningoencephalitis, whereas HIV is a dominant pathogen in subacute dementia and polyneuropathy in patients with AIDS. DHPG may be beneficial in the former, whereas AZT appears to be effective in the latter complications.
Acquired Immunodeficiency Syndrome↗
Cephradine in the treatment of infective endocarditis.
Ten patients with a mean age of 34.1 years with infective endocarditis (55% of cases due to Staphylococcus aureus) were treated with cephradine. The peak serum levels of cephradine (8-42 microgram/ml) were 3- to 17-fold higher than the minimum inhibitory concentrations of cephradine against pathogenic strains of S aureus (1.2-4 microgram/ml). Patients treated with cephradine became afebrile in 2 to 13 days of therapy, and their white blood cell count returned to a normal level in 3 to 30 days. Cephradine therapy was well tolerated without any incidence of phlebitis. The drug could be administered by three different routes. Cephradine is a useful cephalosporin for treatment of nonenterococcal gram-positive endocarditis in young heroin addicts.
Adult↗