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C T Garrett

Publications and source records attributed to C T Garrett.

At least 37 records · Page 2Linked to original sources
PubMed1995

Ras oncogene activation during hepatocarcinogenesis in B6C3F1 male mice by dichloroacetic and trichloroacetic acids.

Dichloroacetic (DCA) and trichloroacetic (TCA) acids, two major by-products formed during chlorine disinfection of drinking water, increase the incidence of tumors in B6C3F1 mice by 6- and 3-fold respectively. In order to understand better the mechanism by which these two compounds induce liver tumors, the incidence and spectrum of mutations in the K- and H-ras proto-oncogenes in these tumors were analyzed. DNA from spontaneous, DCA- and TCA-induced liver tumor from B6C3F1 male mice was evaluated for point mutations in exons 1, 2 and 3 of the two genes by single-stranded conformation polymorphism. Results demonstrated a similar incidence of mutations for exon 2 of H-ras in spontaneous carcinomas (58%), and in carcinomas induced by DCA 3.5 g/l (50%), 1.0 g/l (48%) and TCA 4.5 g/l (45%). Only four showed mutations in the other exons of Hras or in K-ras. Sequence analysis of spontaneous tumor samples with second exon H-ras mutations revealed a change in codon 61 from CAA to AAA in 80% and CAA to CGA in 20% of tumors. In contrast, tumors with H-ras mutations from DCA-treated mice revealed a H-61 change from CAA to AAA in 21% at 3.5 g/l and 16% at 1.0 g/l. CAA to CGA was observed in 50% of tumors from mice given DCA 3.5 or 1.0 g/l, and CAA to CTA was present in 29% and 34% of the two dosage groups respectively. Interestingly, TCA showed the same mutational spectrum as the spontaneous liver tumors. The data indicates that induction of liver carcinoma by DCA and TCA involves activation of the H-ras proto-oncogene at a frequency similar to that observed in spontaneous tumors. However, the mechanism(s) for including hepatocellular carcinoma does not appear to be identical for DCA and TCA.

Animals↗
PubMed1995

Polymerase chain reaction detection of immunoglobulin gene rearrangement and bcl-2 translocation in archival glass slides of cytologic material.

Cytologic evaluation of lymph node fine-needle aspirates and serous effusions is a rapid and useful means for establishing the diagnosis of a variety of lymphoproliferative disorders. However, in some instances, cytologic findings are not sufficient to establish a diagnosis of lymphoma, thus necessitating the use of ancillary procedures, the most frequent of which is immunophenotyping. In this respect, the usefulness of molecular markers, such as clonal immunoglobulin gene rearrangements or chromosomal translocations, have been less well evaluated. Follicular lymphoma constitutes an interesting disease for such a study because these tumors possess characteristic histopathologic features and contain two potential molecular markers, that is, a clonal immunoglobulin gene rearrangement and a bcl-2 gene translocation [t(14;18)]. In the present study, we evaluated, retrospectively, the cytologic material from four lymph node fine-needle aspirates and one pleural effusion of five patients with biopsy-proven follicular lymphoma. In four of the cases, definitive diagnosis of lymphoma had not been possible solely from cytologic evaluation. DNA was isolated from archival air-dried samples present on glass slides and amplified by the polymerase chain reaction (PCR) for detection of either a clonal immunoglobulin heavy chain gene rearrangement or bcl-2 translocation (major breakpoint region). An immunoglobulin heavy chain gene rearrangement was detected in four of five patients, and two patients had the bcl-2 translocation by PCR. The effusion case was identical by gel electrophoresis with product amplified from a lymph node biopsy of the same patient and DNA extracted directly from fresh pleural effusion cells.(ABSTRACT TRUNCATED AT 250 WORDS)

B-Lymphocytes↗
PubMed1995

Genetics of colorectal and breast cancer.

Colorectal and breast cancers account for a significant number of deaths due to malignant neoplasia. Laboratory medicine plays an important role in the diagnosis and management of these tumors through the application of histopathology, immunohistochemistry, and serologic identification of tumor markers. Approximately 5% to 10% of colorectal and breast cancers result from an inherited predisposition. The genes responsible for most genetically transmitted cancers have been identified, and the application of findings from molecular pathology are being evaluated. This article reviews the genetic changes that occur as a result of somatic mutation and inherited or germline mutations.

Adenomatous Polyposis Coli↗
PubMed1994

Prognostic significance of p53 overexpression in endometrial cancer.

Abnormalities of p53, a tumor suppressor gene, have been considered to play an important role in tumorigenesis. Clinically, overexpression of p53 has been reported to correlate with poor prognosis in several types of tumors. In this study, we examined 221 cases of endometrioid endometrial carcinoma for overexpression of p53 using immunohistochemistry in patients with a median follow-up of 41 months. Immunohistochemical analysis was performed with monoclonal antibody pAb1801. Overexpression of p53 was detected in 47 of 221 cases (21.3%). There was a statistically significant correlation between p53 overexpression and poor prognosis (P < .0001). In the early stages of cancer (stages 1 and 2), p53 was overexpressed in 11 of 22 patients (50%) who died or had a recurrence during follow-up. In contrast, overexpression was detected in only 14.7% of the 156 disease-free patients during the same period (P < .0001). In advanced stages (stages 3 and 4), tumors from patients with recurrent disease had a higher frequency of overexpression (41.2%; 7 of 17) than those of disease-free patients (23.1% 6 of 26). However, the difference between these frequencies was not statistically significant. In multivariate analysis using the Cox proportional hazard model, p53 overexpression was an independent risk factor when compared with clinical stage, nuclear grade, and patient age. Our results indicate that p53 immunohistochemical evaluation of the most common form of endometrial cancer may be useful in identifying cases of aggressive carcinoma, especially in the early stages.

Carcinoma, Endometrioid↗
PubMed1993

Optimization for detection of cytomegalovirus by the polymerase chain reaction (PCR) in clinical samples.

PCR is 100 times more sensitive than traditional tube culture for detecting cytomegalovirus (CMV) but may require up to 12 reactions per specimen (Sandin et al., 1991). In order to make the assay practical for use in a clinical laboratory the procedure used to detect CMV must be simplified. In this study, the effect of reducing the number of reactions per specimen on sensitivity and specificity of the PCR assay was evaluated. 53 residual samples from specimens processed for CMV by shell vial assay/routine tube tissue culture (SVA/TTC) were analyzed by PCR. The residual samples were separated into a supernatant and pellet fractions, then tested for CMV with primers to the immediate early (IEP) and late protein (LP) genes using a nested procedure. To exclude false negatives due to the presence of inhibitors in the sample fractions, all fractions were tested for the presence of the human myosin heavy chain gene also using a nested procedure. SVA/TTC had a sensitivity and specificity of 52/96% in comparison to PCR when data from all 12 PCR reactions was considered. However, high sensitivity and specificity were retained when only the data of the IEP primers with two samples were considered. The results from examining only the 1:10 dilution of pellet and the undiluted supernatant by PCR provided a 60% increase in sensitivity over SVA/TTC, high specificity and a clinically feasible assay.

Base Sequence↗
PubMed1993

Viral DNA in microdissected renal biopsy tissue from HIV infected patients with nephrotic syndrome.

Focal glomerulosclerosis (FGS) has been considered as HIV-associated nephropathy, a specific renal complication of infection. To determine whether renal disease in HIV infected patients has one highly prevalent pathologic expression, and whether renal parenchymal viral genomic incorporation affects pathologic outcome, we reviewed renal biopsies performed at our center. Twenty-eight HIV infected patients with nephrotic range proteinuria underwent renal biopsy for diagnosis of renal disease: 85.7% led homosexual or bisexual lifestyles; 10.7% admitted to intravenous drug use; and 85.7% were Black. Only 53.6% had FGS; 28.6% had glomerulonephritis. Two patients had diabetic renal disease; 93.3% of patients with FGS and 87.5% of patients with glomerulonephritis were Black. Paraffin slides of twenty-two of the patients' renal biopsies were evaluated by polymerase chain reaction (PCR) for the presence of HIV DNA, using primers and probes to the gag gene, detected by liquid hybridization and polyacrylamide gel electrophoresis. Twenty-one of the twenty-two evaluated tissue specimens showed the presence of HIV DNA. Microdissection studies of glomeruli, tubules, interstitial cells and infiltrating inflammatory cells showed the presence of HIV genome in all but interstitial cells. HIV infected patients without renal disease also had positive PCR evaluations of microdissected tissue, while non-infected patients were all negative. We conclude that although focal glomerulosclerosis is the most common renal pathologic lesion in patients with HIV infection and nephrotic range proteinuria, glomerulonephritis is a relatively frequent finding. HIV genome is present in renal tissue in HIV infected subjects with nephrotic range proteinuria, but is also found in HIV infected subjects without nephropathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

HIV-associated immune-mediated renal disease.

Although focal glomerulosclerosis is the most common renal disease, other proliferative glomerulonephritides are encountered in HIV-infected patients. We studied four HIV-infected patients with renal insufficiency, proteinuria, and proliferative glomerulonephritis, consistent with immune-mediated disease, to investigate the role of the virus and immune complexes in the pathogenesis of the nephropathy. Circulating immune complexes (CICs) and HIV-reactive antibodies were measured and characterized in each patient. Renal biopsy tissue was acid eluted, and the eluate analyzed. DNA extracted from biopsies was subjected to the polymerase chain reaction (PCR) to detect HIV genome. CICs were detected in each patient: an IgA-p24 HIV antigen complex and an IgG antibody-gp 120 HIV antigen complex in two patients; two patients had an IgG-p24 HIV antigen complex. Identical complexes were eluted from renal tissue in the first three patients; p24 HIV antigen, and complement from the fourth. The eluted antibodies reacted with the HIV antigens from the isolated CICs. Direct immunofluorescence for viral antigen in the eluted glomerular tissue revealed HIV antigens; PCR confirmed the presence of gag genome in all four biopsies. We conclude both circulating and in-situ HIV antigen-specific immune complexes may be associated with glomerulonephritis in HIV infected patients. Viral incorporation into renal tissue may be important in the pathogenesis of HIV-associated renal disease.

AIDS-Associated Nephropathy↗
PubMed1992

Clinical implications of K-ras mutations in malignant epithelial tumors of the endometrium.

Tumorigenesis in humans and experimental animals appears to involve the activation of ras protooncogenes for a number of organ systems and seems to be important to the development of the metastatic phenotype in several model systems. Clinically, the presence of activated ras protooncogenes has been reported to be a negative prognostic factor in the myelodysplastic syndrome and in adenocarcinoma of the lung. In the present study we examined 49 cases of endometrial carcinoma for mutations in the first exon of K-ras using the polymerase chain reaction and direct sequencing. Mutations in codon 12 or 13 of K-ras were detected in 6 of 49 cases (12.2%). These six cases consisted of five endometrioid endometrial carcinomas, each of which had a mutation in codon 12, and one case of clear cell carcinoma, which had a mutation in codon 13. In our study the presence of mutations in K-ras appeared to be an unfavorable prognostic factor. Three of six patients with the mutation died during follow-up, while only 7% of the 43 patients without K-ras mutations expired during this same period. In multivariate analysis using the Cox proportional hazard model, K-ras activation appeared to be an independent risk factor when compared with clinical stage, depth of myometrial invasion, and patient age. Thus, our findings support the hypothesis that K-ras protooncogene activation plays an important role in determining the aggressiveness of endometrial carcinoma.

Base Sequence↗
PubMed1992

Oncogenes in gynecological tumors.

Evidence is increasing that proto-oncogenes and cancer suppressor genes are involved in the development and/or progression of gynecological malignancies. While histopathologic examination remains an indispensable tool of the surgical pathologist in the diagnosis and evaluation of patients with gynecological malignancies, the advancement to technology and the development of new knowledge regarding neoplastic transformation are providing a basis for new opportunities to improve patients care. These new opportunities will depend on the use of the skills and reagents developed in the basic medical science laboratories. Thus, it is important for those in the field of diagnostic pathology to begin to acquire a knowledge of proto-oncogenes and cancer suppressor genes as well as a basic understanding of the techniques used to detect and evaluate them.

Cell Transformation, Neoplastic↗
PubMed1991

Cardiac myocytes and dendritic cells harbor human immunodeficiency virus in infected patients with and without cardiac dysfunction: detection by multiplex, nested, polymerase chain reaction in individually microdissected cells from right ventricular endomyocardial biopsy tissue.

Two hundred fifteen patients infected with human immunodeficiency virus (HIV) participated in a prospective longitudinal study of HIV-related heart disease. Evaluation included signal-averaged electrocardiography and echocardiography. Fifteen patients underwent endomyocardial biopsy, 5 had cardiovascular symptoms and 10 did not. Cardiac myocytes or dendritic cells were prepared by individual cell microdissection to sort them from other cell types such as interstitial cells or circulating blood elements. HIV proviral sequences were amplified in samples of 15 to 20 cells of each type by multiplex, nested, polymerase chain reaction and hybridized to 32P-labeled probes specific for regions within the gag and pol genes of HIV-1. The results showed the presence of HIV sequences in myocytes of 2 of 5 patients with cardiac symptoms and in 6 of 10 without. Thus, symptomatic HIV cardiomyopathy did not appear to be a direct consequence of the virus on myocardial cells. In dendritic cells, HIV sequences were detected in 5 of 5 patients with cardiac symptoms and in 8 of 10 with apparently normal ventricular function. Furthermore, dendritic cells were somewhat more numerous in the myocardium of symptomatic than asymptomatic patients. Our studies are the first to directly detect the HIV genome in purified cardiac myocytes from patients with and without cardiac dysfunction. Our findings do not support a direct role of the virus in myocardial dysfunction. However, the results do suggest that the interstitial dendritic cells may be involved in some manner in the development of cardiac dysfunction observed in HIV-infected patients.

Adult↗
PubMed1991

Clonal rearrangement of the T-cell receptor beta-chain gene in hyperplastic lymphadenopathy associated with lung cancer.

A patient presenting with marked inflammatory lymphadenitis and Jaccoud's arthritis was found to have a rearranged gene for the beta-chain of the T-cell receptor (TCR-beta) antigen in the lymph node DNA digests and normal germ line DNA in the peripheral blood lymphocytes. Four months later, the patient was diagnosed to have poorly differentiated adenocarcinoma of the lung with small foci of metastatic tumor in lymph nodes that contained the same extensive lymphocytic and inflammatory cell infiltrates noted earlier. Rearranged TCR-beta chain genes were detected in both lymph node and peripheral blood lymphocyte DNA at this time. The most likely explanation for the florid lymph node reaction and the unusual arthropathy appears to be a paraneoplastic immune response. The rearranged TCR-beta genes indicate a clonal T-cell expansion that most likely resulted from the aberrant immunologic response to the lung cancer.

Aged↗
PubMed1991

Comparison of sensitivity for human cytomegalovirus of the polymerase chain reaction, traditional tube culture and shell vial assay by sequential dilutions of infected cell lines.

Although traditional tube culture (TTC) is still considered by many as the 'gold standard' for the laboratory diagnosis of human cytomegalovirus (HCMV), the shell vial assay (SVA) offers greater speed of detection. This technique utilizes immunofluorescence (IF) to detect early or immediate early nuclear antigens (IEA). The detection capabilities of these two tests were compared with the polymerase chain reaction (PCR), a technique that amplifies enzymatically selected DNA target sequences. Serial dilutions of crude culture harvests from 2 HCMV strains, Towne and a clinical urine isolate, were made up to 1:1 000,000. Ten-microliters aliquots of the original sample and each dilution were tested by PCR, TTC and SVA. For PCR, the nested-primer approach was used. Outer primers delimited a 721-bp sequence contained within the 2nd to 4th exons of the immediate-early protein. Inner nest primers delimited a 167-bp sequence in the third exon, detected by a 32P-labelled probe. The results show that: (1) control samples which contained all PCR reagents but no DNA were uniformly negative; (2) radiolabelled-probe detection (RPD) of PCR products is, on average, 100 x more sensitive than detection by ethidium bromide; (3) PCR is, on average, 100 x more sensitive than evaluation of cytopathic effect (CPE) in the TTC; (4) the predictive value of a negative SVA result is low compared to PCR.

Base Sequence↗
PubMed1991

Gene rearrangements in the diagnosis of lymphoma/leukemia. Guidelines for use based on a multiinstitutional study.

The demonstration of immunoglobulin or T-cell receptor gene rearrangements in human lymphoproliferative processes with the use of DNA hybridization has gained great popularity as a sensitive laboratory adjunct to diagnostic hematopathology. The fact that nearly all B- or T-cell malignant lymphomas and leukemias have one or more rearranged antigen receptor genes provides a biologic basis for a diagnostic test. To formally analyze the sensitivity, specificity, and reproducibility of gene rearrangements in the diagnosis of human lymphoproliferative disease, the authors conducted a large, multiinstitutional study. Through a blinded, controlled approach, gene rearrangement analysis of 275 cases was shown to carry a high correlation with conventional phenotyping and histologic diagnosis, with only minor false-positive and false-negative rates. Significantly, no rearrangements were detected in normal lymphoid tissues or carcinomas, sarcomas, or melanomas. In a randomized study of 50 cases, laboratory results showed a high rate of interlaboratory agreement, regardless of the level of previous experience. Furthermore, the reproducibility of interpretation of data (Southern blot autoradiograms) of 192 cases showed high concordance among 11 observers from multiple laboratories. Based on these findings, the authors propose a set of guidelines for interpretation of gene rearrangement analysis that, if carefully followed, renders this a highly reproducible, safe, and accurate addition to the diagnostic regimen for human lymphoproliferative processes.

B-Lymphocytes↗
PubMed1991

Human papilloma virus in uterine cervix: a comparison of detection by morphology and by dot-blot hybridization.

Colposcopically directed cervical biopsies, smears, and swabs obtained from 210 women with a previous abnormal cervical cytology were evaluated for the presence of human papilloma virus (HPV) using morphology and dot-blot hybridization. The diagnosis of HPV infection in biopsies and smears examined morphologically was rendered using established criteria for condyloma/cervical intraepithelial neoplasia (CIN). In hybridization studies, DNA was isolated from cells obtained from cervical swabs and annealed with probes that detected HPV types 6/11, 16/18, and 31/33/35 using a dot-blot procedure. Ninety-five cases demonstrated morphologic evidence of condyloma/CIN; 51 of these (54%) were positive for HPV DNA (five cases 6/11, 21 cases 6/18, 20 cases 31/33/35, and five cases two different probes). HPV DNA was also detected in 6 of the 115 cases (5.2%) that were morphologically negative (three cases 16/18, three cases 31/33/35). The results demonstrated that morphology was more sensitive than dot-blot hybridization for detection of HPV-related lesions. The dot-blot hybridization did detect HPV DNA in a small percentage of the cases that showed no morphologic abnormality and was useful for typing of the HPV. At this juncture, however, the clinical significance of the latter findings is unclear.

Cervix Uteri↗
PubMed1990

An analysis of abnormalities of the retinoblastoma gene in human ovarian and endometrial carcinoma.

The altered expression of the human retinoblastoma (RB) gene has been demonstrated to play an important role in the pathogenesis of RB and other tumors. To determine whether the RB gene might be involved in the pathogenesis of human ovarian and endometrial cancer, DNA from 24 human ovarian tumors, 3 normal ovaries, 3 endometrial carcinomas, and 1 endometrial hyperplasia was examined with an RB complementary DNA probe. Evidence for homozygous deletion of the RB gene was observed in only one specimen. Interestingly, the specimen was an endometrioid tumor of the ovary of low malignant potential (LMP). This patient experienced rapid progression of the tumor and died 8 months after diagnosis. Abnormalities of the RB gene may be involved in the aggressive biologic behavior of certain forms of ovarian carcinoma, particularly those of LMP.

Aged↗