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Biomedical subjects

M Ayoub

Publications and source records attributed to M Ayoub.

29 records · Page 2Linked to original sources
PubMed1995

Assessment of the infectivity of corneal buttons taken from hepatitis B surface antigen seropositive donors.

Sixty one corneas taken from 33 hepatitis B surface antigen (HBsAg) seropositive donors and 20 control corneas taken from 12 HBsAg seronegative donors were tested for the presence of HBsAg using reversed passive haemagglutination (RPHA) and enzyme linked immunosorbent assay (ELISA) and for the presence of hepatitis B virus core DNA (HBVcDNA) using the hybridisation technique in their epithelium, stroma endothelium, and storage media. HBsAg was detected by ELISA in the epithelium of one cornea (1.6%), in the stroma endothelial suspensions of six corneas (9.8%), and in the storage media of five corneas (8.2%). HBVcDNA was detected for the first time in the cornea; in the epithelium of four corneas (6.6%), stroma endothelium of nine corneas (14.8%), and the storage media of five corneas (8.2%). The control corneas were negative for HBsAg, while HBVcDNA was detected in the stroma endothelium of two corneas (10%) and in the media of two corneas (10%). This study confirmed that HBV can be present in the human cornea. Preservation in corneal storage media for up to 6 days could not eliminate the virus from the cornea. The possibility of HBV transmission through corneal transplantation should not be overlooked.

Contraindications↗
PubMed1989

Lysis of oocytes by bovine sperm and seminal plasma.

This study examined the lytic activity of bovine seminal plasma on zona-free oocytes commonly used to assess bovine capacitation. Exposure of hamster oocytes (intact or zona-free) to undiluted seminal plasma resulted in lysis within 5 min. With intact oocytes, 1:5 to 1:20 seminal plasma resulted in swelling of the oocytes. With zona-free oocytes, seminal plasma (1:0 to 1:1000) resulted in lysis within 1 min to 3 h depending on dilution. Heating seminal plasma to inactivate complement did not reduce lytic activity, but boiling destroyed it. Lytic activity was present in seminal plasma from vasectomized bulls and in seminal vesicle fluid. After elution of seminal plasma through Sephadex G-200, lytic activity was only associated with the fraction containing proteins of 200,000 to 45,000 dal. Lytic activity remained with washed capacitated bull sperm only when 10(7) sperm/ml or more were coincubated with zona-free oocytes at 37 degrees C for 3 h. In conclusion, both bovine seminal plasma and capacitated sperm were lytic in the zona-free hamster oocyte assay. The results may explain why so few sperm are normally found at the site of fertilization.

Animals↗
PubMed1978

Antenatal blood group serology in Sudanese women.

2,140 pregnant Sudanese women attending the antenatal clinic in Omdurman Maternity Hospital during the period November 1975 to December 1976 had ABO and Rh typing performed. Their sera were also screened by a modified papain enzyme technique for the presence of atypical antibodies. The rate of Rhesus immunization, the frequency distribution of blood groups, the atypical antibodies encountered, and the advantages of the method used for screening the sera in a developing country are discussed.

ABO Blood-Group System↗
PubMed1976

Bombay (Oh) blood in a Sudanese family.

Two examples of Bombay Oh blood were found in siblings of a Sudanese family. They belong to a tribe of Arab and Negro extraction. This is the first report of this rare blood group in people of Arab or Negro origin.

ABO Blood-Group System↗
PubMedDate not supplied

Maternal weight differences do not explain ethnic differences in biochemical screening.

In previous work, we and others have shown that serum levels of alpha-fetoprotein, human chorionic gonadotropin, and estriol vary among the four commonly defined racial/ethnic groups seen in the United States: white, African-American, Asian, and Hispanic. We have suggested that better sensitivity and specificity could improve screening sensitivity and specificity. However, it has been argued that systematic weight differences among the groups could explain the variation. We evaluated the results from 208,257 patients having screening and found systematic weight differences. However, these differences were not as large as the racial/ethnic differences, showing that weight does not fully explain the discrepancy, and, therefore, four separate data bases give more accurate results.

Asian↗
PubMedDate not supplied

Variability of adjustments to indices in determining patient risk in biochemical screening.

It has long been appreciated that the measurement of biochemical parameters for prenatal screening for neural tube defects, and later aneuploidy, is not as simple as measuring hemoglobin or hematocrit. Early in the game, it was recognized that there are gestational age curves, and that since alpha-fetoprotein (AFP), for example, is a fetal product, its distribution varies as a function of maternal plasma volume, and therefore the weight of the mother. A number of different adjustment factors have been used for AFP and other parameters for years, with varying degrees of consistency and reliability. Here we review a number of adjustments that have been used, and try to give priority to those that have been most effective. Furthermore, laboratories and programs need to be cognizant that with newer parameters being added, the specifics of requirements will vary on a case-by-case parameter basis, and optimal screening can only be achieved with the appropriate adjustments.

Biomarkers↗