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Biomedical subjects

C Garber

Publications and source records attributed to C Garber.

9 recordsLinked to original sources

A multidisciplinary approach to the early detection of ovarian carcinoma: rationale, protocol design, and early results.

OBJECTIVE: This study was undertaken to determine the feasibility of currently available tests to detect ovarian cancer at a curable stage. By studying women at risk for the disease on the basis of their family histories of cancer, we hope to gain insight into the genetics and biologic characteristics of ovarian cancer. STUDY DESIGN: Asymptomatic women with a family history of cancer are interviewed by geneticists to obtain accurate pedigree and epidemiologic data. Screening tests including transvaginal ultrasonography, color Doppler imaging, CA 125 measurement, and other investigative biomarkers are performed between cycle days 3 and 8 and repeated biannually. RESULTS: A total of 597 women without symptoms were screened between July 1991 and June 1992. Cystic or complex adnexal masses were detected in 6.2% of patients. A pulsatile index value < 1.0 was measured in 80% of premenopausal patients and 24% of postmenopausal patients, whereas a resistance index value < 0.4 occurred in 12% of premenopausal and 3% of postmenopausal patients. A CA 125 level > 35 U/ml was found in 11.4% of the study participants. To date, one stage IA borderline ovarian tumor and one endometrial carcinoma have been found. CONCLUSIONS: Ovarian cancer screening needs to be investigated in a controlled fashion to determine means that will ultimately improve the survival from the disease.

Adult

Complete nucleotide sequence of a simian immunodeficiency virus from African green monkeys: a novel type of intragroup divergence.

We have determined the entire nucleotide sequence of a full-length molecular clone, termed SIVagm3, which is infectious in vitro and in vivo. The genomic organization was found to be similar to other immunodeficiency viruses of human and simian origin. Comparison of SIVagm3 with SIVagmTYO-1, the only other completely sequenced molecular SIVagm clone, revealed a novel type of intragroup divergence, which is characterized by (1) an unusually high degree of variability in pol in relation to gag and env and (2) a high degree of divergence in the rev and tat genes. Thus, since SIVagm3 and SIVagmTYO-1 evolved from their common ancestor, they diverged in a different manner than human immunodeficiency viruses. Hypervariable regions in env were defined and shown to be relatively restricted in comparison to HIV-1 and HIV-2.

Amino Acid Sequence

Molecularly cloned simian immunodeficiency virus SIVagm3 is highly divergent from other SIVagm isolates and is biologically active in vitro and in vivo.

Simian immunodeficiency viruses have been isolated from African green monkeys originating from Ethiopia. A molecular clone, termed SIVagm3, was found to be highly divergent from SIVagmTYO-1 in terms of its restriction map and partial nucleotide sequence. A premature stop codon present in the transmembrane protein of SIVagm TYO-1 was absent in SIVagm3. SIVagm3 was biologically active in vitro and in vivo and displayed characteristics reminiscent of the wild-type virus. Biological activity was demonstrated by seroconversion of juvenile African green monkeys and Macaca nemestrina after inoculation. In contrast to antibody reactivity mainly directed against env proteins in naturally infected African green monkeys. African green monkeys and M. nemestrina infected with the cloned virus showed antibody reactivity directed against all major proteins as demonstrated by immunoblot analysis. The availability of a biologically fully competent molecular clone of SIVagm allows us now to address various pertinent questions in an animal model system which should help to understand features of human immunodeficiency virus infection in human beings.

Amino Acid Sequence

Self-inactivating retroviral vectors designed for transfer of whole genes into mammalian cells.

A retrovirus-derived vector called self-inactivating (SIN) vector was designed for the transduction of whole genes into mammalian cells. SIN vectors contain a deletion of 299 base pairs in the 3' long terminal repeat (LTR), which includes sequences encoding the enhancer and promoter functions. When viruses derived from such vectors were used to infect NIH 3T3 cells, the deletion was transferred to the 5' LTR, resulting in the transcriptional inactivation of the provirus in the infected cell. Introduction of a hybrid gene (human metallothionein-promoted c-fos) into cells via a SIN vector was not associated with rearrangements and led to the formation of an authentic mRNA transcript, which in some cases was induced by cadmium. SIN vectors should be particularly useful in gene transfer experiments designed to study the regulated expression of genes in mammalian cells. Absence of enhancer and promoter sequences in both LTRs of the integrated provirus should also minimize the possibility of activating cellular oncogenes and may provide a safer alternative to be used in human gene therapy.

Chromosome Deletion

A candidate reference method for uric acid in serum. II. Interlaboratory testing.

We describe the interlaboratory testing of a candidate Reference Method (Part I) for uric acid in serum. The method is based on the ultrasound spectrophotometric quantitation of uric acid before and after incubation with uricase. A comprehensive investigation involving 12 laboratories was organized to document the transferability, intra- and interlaboratory precision, and general reliability of the candidate Reference Method. The interlaboratory CV with this method was about 2 to 6% for uric acid concentrations ranging from 0.12 to 0.60 mmol/L. The results detailed here demonstrate that the method can be successfully duplicated among different laboratories.

Evaluation Studies as Topic

Immobilized-enzyme rate-determination method for glucose analysis.

We present a rate-determination method for analyzing glucose. A glucose enzyme electrode serves as the sensor and is made by placing a gel-immobilized layer of glucose oxidase over the tip of a Clark-type O2 electrode. The electrode membrane is made of Teflon and is derivatized by etching with a suspension of colloidal sodium metal in organic solvent. The enzyme is coupled to the membrane surface by use of paraformaldehyde. The immobilized-enzyme method is compared with a similar solution-enzyme method and with the National Glucose Reference method. The immobilized enzyme method compares favorably with the solution-enzyme method and offers the advantages of simplicity, economy of enzyme, and linearity over a greater range of concentration.

Ascorbic Acid