Genetic and antigenic analysis of human rotavirus prevalent in Al-Taif, Saudi Arabia.

The subgroup, serotype and electropherotype diversity of human rotavirus strains was investigated in Al-Taif, Saudi Arabia. Out of 349 faecal samples collected from diarrhoeic children, 150 (43 percent) tested rotavirus positive by a group-A specific enzyme-linked immunosorbent assay (ELISA). The majority (87 percent) of the infected children were below 2 years of age. Subgrouping and serotyping of rotaviruses with specific monoclonal antibodies showed that of the 150 rotavirus positive specimens, 17 percent belonged to subgroup I, 59 per cent belonged to subgroup II, and 24 percent were neither subgroup I nor subgroup II. The specimens were typed, as serotype 1 (43 percent), serotype 2 (5 percent), serotype 3 (11 percent), serotype 4 (10 percent) or mixed serotypes (3 percent). The remaining 41 (27 percent) specimens were untypeable. None of the serotypes showed association with a particular age group. An electrophoretic analysis of viral RNA revealed 11 distinct patterns (six long and five short). The majority, 78 percent were long patterns and 22 percent were short patterns. Analysis of the specimens for which subgroups, serotypes and electropherotypes were available indicated that a given RNA pattern does not correspond to a particular subgroup or serotype.

Human rotavirus genomic RNA electropherotypes in Jeddah, Saudi Arabia from 1988 to 1992.

Polyacrylamide gel electrophoresis was used to analyze the double-stranded RNA of rotavirus recovered from stool specimens collected between March 1988 and December 1992 from children with acute diarrhoea admitted to the central hospital in Jeddah, Saudi Arabia. Rotavirus was detected by ELISA in 523 specimens of the 1242 collected during the study, giving an overall prevalence of 42.2% for the 5 years of investigation. Out of 523 rotavirus-positive specimens, 263 (50.3%) were successfully electropherotyped. Eighteen different electropherotypes were observed, 12 long patterns and six short patterns. Eighty-seven per cent of the electropherotypes were of the long RNA pattern. The remaining were short electropherotypes. The predominant electropherotypes were two long patterns and maintained dominance over 5 years of the study. The third most predominant pattern was a short electropherotype. The remaining electropherotypes made minor contributions every year. These predominant electropherotypes were different from the predominant patterns detected in many countries. Temporal distribution was observed for 5 successive years for the predominant electropherotypes, with an increase in the incidence during the cooler months of the year.

Human rotavirus subgroups and serotypes in children with acute gastroenteritis in Saudi Arabia from 1988 to 1992.

Rotavirus infection was detected in 524 (42.2%) of the 1,242 stool specimens collected from infants and young children with acute gastroenteritis admitted to a major pediatric hospital in Jeddah, Saudi Arabia, between March 1988 and December 1992. Enzyme-linked immunosorbent assay (ELISA) and monoclonal antibodies specific for subgroup I and II were used to examine 80 rotavirus positive specimens. Subgroup I was detected in 21 (26.3%) and subgroup II in 49 (61.3%) specimens. Six specimens reacted with both subgroup I and II monoclonal antibodies and four specimens were untypeable. Serotyping of 355 rotavirus positive specimens using monoclonal antibodies specific for the human rotavirus serotypes 1 to 4 revealed a distribution profile of serotype 1, 53.5%; serotype 2, 6.8%; serotype 3, 5.9%; and serotype 4, 22.8%, along with mixed and untypeable specimens (11%). When the correlation between subgroup and serotype specificities was examined in 62 specimens, all subgroup I specimens were found to be serotype 2 or untypeable and all subgroup II specimens belonged predominantly to serotypes 1 (54.7%) and 4 (9.4%). Serotype 1, followed by, to a lesser extent, serotype 4, exhibited a temporal predominance in the 5-year investigation. A significant clustering of the various serotypes during the cooler months was evident almost throughout the study, particularly in 1989 and 1990.

Rotavirus infection in children in Saudi Arabia.

Three hundred sixty-three fecal specimens were collected from infants and young children with gastroenteritis over a 13-month period in Jeddah, western Saudi Arabia. Rotavirus was detected in 46% of the 363 specimens tested using an enzyme-linked immunosorbent assay (ELISA), and in 40.7% of 113 specimens using a latex agglutination test. One hundred nine of the 113 specimens that were positive by the latex agglutination test were also positive by ELISA. Electron microscopy was used to examine some specimens to demonstrate the presence of the virus. Rotavirus was detected throughout the 13-month study period, with an increase in the frequency of infection in the cooler months. Infection with this virus was more frequent among infants and children less than two-years old, with a maximum incidence among children 13-15 months old. In the 363 stool specimens tested, rotavirus was found in mixed infections with bacteria in 0.44%, with parasites in 1.31%, and with yeast in 0.66%.

Nuclear antigens in the HeLa cell cycle.

Antisera to 0.35 M NaCl extracts and residues of S phase HeLa nuclei were reacted with electrophoretically separated proteins from the nuclei or nuclear material of HeLa cells synchronized in G1, S, G2 or M phases of the cell cycle. Quantitative evaluation of the peroxidase-antiperoxidase stained nitrocellulose transfers (Western blots) revealed significant changes in the quantities of nuclear non-histone proteins during the cell cycle. Immunochemical staining of electrophoretically separated nuclear antigens permits their selective detection in minute quantities and in the presence of many additional proteins.

cis-Diamminedichloroplatinum-mediated crosslinking of nuclear proteins to DNA is cell cycle specific.

Immunochemical analysis was employed to investigate the cell cycle-dependent protein-DNA crosslinking by cis-diamminedichloroplatinum II (cis-DDP), in HeLa-S3 cells. Cells synchronized by double thymidine block or hydroxyurea were released into S phase and incubated at 2-h intervals with cis-DDP as they progressed through S1, G2, M, and then into G1 and S phases of the subsequent cycle. Immunoblots of the DNA-crosslinked antigens reacted with antisera to 0.35 M NaCl extract or residue of HeLa S-phase nuclei revealed that several antigens changed their DNA-crosslinking pattern during the progression of HeLa cells through their reproductive cycle.

cis- and trans-Diamminedichloroplatinum(II)-mediated cross-linking of chromosomal non-histone proteins to DNA in HeLa cells.

The cross-linking of chromosomal non-histone proteins to DNA in isolated nuclei or intact HeLa cells exposed to different concentrations of cis- and trans-diamminedichloroplatinum(II) (cis- and trans-DDP) for various time intervals was investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunochemical methods. Both the cis- and the trans-DDP cross-linked significant numbers of chromosomal non-histone proteins to the DNA. The quantity and the types of the cross-linked proteins depended on the time of incubation as well as on the concentrations of the drugs. The immunochemical techniques revealed that both the 0.35 M sodium chloride insoluble and soluble chromosomal non-histone proteins were cross-linked to the DNA by both isomers. The action of cis- and trans-DDP was reversed and/or blocked by thiourea or 2-mercaptoethanol. Pretreatment of isolated nuclei or chromatin with iodoacetamide or N-ethylmaleimide did not prevent the DNA-protein cross-linking.

Crosslinking of chromosomal proteins to DNA in HeLa cells by UV gamma radiation and some antitumor drugs.

Immunochemical techniques were used to investigate the protein-DNA crosslinking by ultraviolet (UV) and gamma radiation as well as 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) or cis- and trans-diamminedichloroplatinum II (cis-DDP and trans-DDP). Antisera to 0.35 M NaCl extract and 0.35 M NaCl residue of HeLa nuclei were employed. Both gamma and UV irradiation, exposure to cis- or trans-DDP and, to a lesser extent, BCNU, resulted in crosslinking of various antigens to the DNA. Although several antigens were crosslinked by all the employed agents, other exhibited agent-specific crosslinking patterns.