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Biomedical subjects

R Greenspan

Publications and source records attributed to R Greenspan.

11 recordsLinked to original sources

Distinct protein forms are produced from alternatively spliced bicistronic glutamic acid decarboxylase mRNAs during development.

It has been shown that the enzyme glutamic acid decarboxylase (GAD; EC 4.1.1.15), which catalyzes the conversion of L-glutamate to gamma-aminobutyric acid in the central nervous system of vertebrates, can be first detected in rodents at late embryonic stages. In contrast, we have found that the gene coding for the 67-kDa form of GAD is already transcriptionally active at embryonic day E10.5 in the mouse. In addition to the 3.5-kb adult-type mRNA, we have detected two 2-kb embryonic messages that contain alternatively spliced exons of 80 (I-80) and 86 (I-86) bp, respectively. The overlapping stop-start codon TGATG, found in the embryonic exons, converts the monocistronic adult-type transcript into a bicistronic one, coding for a 25-kDa leader peptide and a 44-kDa enzymatically active truncated GAD. A second stop codon at the 3' end of the 86-bp exon abolishes the expression of truncated GAD. The products of the two embryonic mRNAs were identified in a rabbit reticulocyte in vitro translation system, COS cells, and mouse embryos. The two GAD embryonic forms represent distinct functional domains and display characteristic developmental patterns, consistent with a possible role in the formation of the gamma-aminobutyric acid-ergic inhibitory synapses.

Alternative Splicing

Knowledge about AIDS and self-reported behaviour among Zimbabwean secondary school pupils.

Knowledge about AIDS and self-reported sexual behaviour was studied among 1532 (893 male, 633 female) Zimbabwean secondary school pupils drawn from 12 schools. Most subjects knew that AIDS is fatal and incurable. However, over 40% of subjects believed that most people with AIDS in Africa are homosexual. Over 40% of respondents did not know that many HIV seropositive individuals look healthy. Nearly 40% of participants believed that HIV can be contracted from toilet seats and 54% of subjects believed that mosquitos can transmit HIV. Pupils from homes in urban areas were better informed about AIDS than were those from homes in rural areas. Forty-six percent of males and nearly 3% of females were reportedly sexually experienced. It is suggested that female under-reporting of sexual activity occurred. Nearly 16% of males reported coital experience with a prostitute. The implications of these findings for future AIDS awareness campaigns in Zimbabwe are considered.

Acquired Immunodeficiency Syndrome

Knowledge about AIDS among Zimbabwean teacher-trainees before and during the public awareness campaign.

Knowledge about AIDS was studied among 4,189 Zimbabwean teacher-trainees from January to March, 1988, about six months after a national AIDS awareness campaign began. Knowledge about AIDS among part of this sample of teacher-trainees surveyed after the AIDS campaign began was also compared with that displayed by 630 teacher-trainees studied in January, 1987, roughly six months before the AIDS campaign began. Over 85 percent of 1988 subjects knew that AIDS is fatal and incurable. More than 80 percent of 1988 respondents knew that a condom is an effective precaution against AIDS. However, among 1988 participants, 35 percent did not know that many people carrying the AIDS virus look healthy, 36 percent believed that many AIDS victims in Africa are homosexual, 36 percent did not know that one cannot contract AIDS from a toilet seat, 40 percent believed that kissing transmits AIDS and nearly half believed that mosquitoes transmit AIDS. Males and subjects from urban homes were better informed about AIDS than females and those from rural homes, respectively. Teacher-trainees surveyed in 1988 were generally more knowledgeable about AIDS than those studied in 1987. The implications of these results for further educational efforts are considered.

Acquired Immunodeficiency Syndrome

Radiographic findings in the esophagus following the Sugiura procedure.

Sixteen patients underwent a modification of the Sugiura procedure for bleeding esophageal varices, involving (a) esophageal transection, (b) splenectomy, (c) selective vagotomy, and (d) pyloroplasty. Five patients died, and the remaining 11 had barium studies of the esophagus and stomach which were compared with the preoperative appearance. Esophageal varices disappeared in 7 patients and persisted in 1. No recurrent bleeding or encephalopathy was seen: however, there were a large number of complications, including pleural effusion, ascites, ileus, pneumonia, and renal failure. Hepatic failure, respiratory failure, and sepsis secondary to gastrointestinal leakage also occurred and were fatal in all cases. As the Sugiura procedure is increasingly being employed in the United States, radiologists should be familiar with the spectrum of postoperative radiographic findings in the esophagus and stomach.

Adult

Delayed hemolytic transfusion reaction caused by the second example of anti-K19.

A second example of anti-K19 has been identified in the serum of a black patient immunized by blood transfusions. The antibody was responsible for delayed hemolysis of transfused incompatible red blood cells. The patient's red blood cells are K:--19 but are otherwise of common Kell phenotype. The K19 antigen is closely associated with the Kell blood group although there is, as yet, no pedigree information to confirm that it is produced by the Kell gene. Tests on 10,757 group O blood donors have not revealed any further examples of the K:--19 phenotype.

Anemia, Hemolytic, Autoimmune