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Biomedical subjects

J W Reagan

Publications and source records attributed to J W Reagan.

At least 19 recordsLinked to original sources
PubMed1991

In vivo clearance of low-density lipoproteins and beta-very-low-density lipoproteins in normal and hypercholesterolemic White Carneau pigeons.

Low-density lipoproteins (hLDL) and beta-migrating-very-low-density lipoproteins (beta-VLDL) were isolated from the plasma of cholesterol-fed White Carneau (WC) pigeons and low-density lipoproteins (nLDL) were isolated from the plasma of grain-fed WC pigeons. The lipoproteins were radiolabeled with 125I or 131I and injected into normocholesterolemic or hypercholesterolemic WC pigeons to determine their rate of clearance from the plasma. The fractional catabolic rate (FCR) of nLDL and hLDL in normocholesterolemic pigeons averaged 0.202 and 0.206 pools/h.respectively. beta-VLDL was cleared at a significantly slower rate of 0.155 pools/h. The FCR of the same lipoproteins injected into hypercholesterolemic pigeons was reduced by 17% for nLDL, 50% for hLDL and 57% for beta-VLDL, indicating that the effect of hypercholesterolemia on clearance in vivo was different for the three lipoproteins. The FCR of reductively methylated pigeon LDL (MeLDL), which gives a measure of receptor-independent clearance of LDL, was shown previously to be 0.037 pools/h. These studies suggest therefore that LDL and beta-VLDL are cleared from the plasma of normocholesterolemic and hypercholesterolemic pigeons at a rate substantially greater than that predicted for non-specific processes. Despite the reduction in the clearance rate of hLDL and beta-VLDL due to cholesterol feeding, the absolute amount of cholesterol that was cleared from the plasma by these lipoproteins was increased from approx. 200 mg/kg body weight per day in the normocholesterolemic pigeons to greater than 1000 mg/kg body weight per day in the hypercholesterolemic pigeons. This is due principally to the enrichment in cholesterol relative to protein of the lipoproteins isolated from cholesterol-fed pigeons and the failure of hypercholesterolemia to completely inhibit receptor-dependent clearance of LDL and beta-VLDL. The lower rate of clearance of beta-VLDL relative to LDL is in marked contrast to mammalian beta-VLDL, which is cleared much faster than LDL, but is consistent with the lack of apo E on pigeon lipoproteins. Apo E is the apoprotein that is thought to be responsible for the rapid clearance of beta-VLDL in normocholesterolemic mammals. The low rate of beta-VLDL clearance in pigeons also suggests that pigeons lack an apolipoprotein that function like mammalian apo E.

Animals↗
PubMed1990

In vivo clearance of low density lipoprotein in pigeons occurs by a receptor-like mechanism that is not down-regulated by cholesterol feeding.

The contribution of receptor-dependent and receptor-independent mechanisms for low density lipoprotein (LDL) clearance in vivo was determined in White Carneau and Show Racer pigeons fed either cholesterol free or cholesterol containing diets. The methylation of pigeon LDL resulted in the inhibition of recognition by the LDL receptor which allowed its use as a tracer of receptor-independent clearance. The fractional catabolic rate (FCR) of radiolabeled LDL in 20 control pigeons (means +/- S.E., 0.277 +/- 0.013 pools/h) was approximately seven times faster than for methylated LDL indicating that 86% of the total LDL clearance occurred by a receptor-mediated process. Total LDL clearance was reduced by 27% (FCR = 0.202 +/- 0.012 pools/h) in 14 cholesterol-fed pigeons, but receptor-mediated mechanisms were still responsible for 80% of the total LDL clearance. LDL uptake by individual tissues was measured using the residualizing label 125I-tyramine cellobiose. The liver was the primary site of LDL clearance in both control and cholesterol-fed birds. LDL receptors were active in every tissue examined and accounted for over 85% of the LDL clearance in the liver and over 90% in the adrenal gland. Consistent with the whole body LDL clearance findings, cholesterol-feeding did not significantly reduce receptor-mediated clearance of 125I-tyramine cellobiose-LDL by the liver or any of the other tissues. Hepatic sterol synthesis, however, was reduced by greater than 90% in cholesterol-fed animals. These data are consistent with the conclusion that LDL clearance in vivo in pigeons is mediated primarily by an LDL receptor-like mechanism that shows little down-regulation with hypercholesterolemia even though cholesterol synthesis is efficiently down-regulated.

Adrenal Glands↗
PubMed1989

Induction of cervical neoplasia in the mouse by herpes simplex virus type 2 DNA.

Induction of cervical neoplasia in the mouse cervix by herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) has been reported. The present study was done to determine if transfection with DNA of HSV-2 can induce carcinogenesis in this animal model. Genomic HSV-2 DNA was isolated from infected HEp-2 cells and separated from host cell DNA by cesium chloride density gradient centrifugation. The DNA was applied to mouse cervix for periods of 80-100 weeks. Experimental controls were treated with uninfected genomic HEp-2 cell DNA or with calf thymus DNA. Vaginal cytological preparations from all animals were examined monthly to detect epithelial abnormalities. Animals were sacrificed and histopathology studies were done when cellular changes indicative of premalignant or malignant lesions were seen on vaginal smears. Cytologic and histologic materials were coded and evaluated without knowledge of whether they were from animals treated with virus or control DNA. Premalignant and malignant cervical lesions similar to those that occur in women were detected in 61% of the histologic specimens obtained from animals exposed to HSV-2 DNA. The yield of invasive cancers was 21% in animals treated with HSV-2 DNA. No cancers were detected in mice treated with either HEp-2 or calf thymus DNA. Dysplasia was detected in only one of these control animals.

Animals↗
PubMed1986

Roles of cytomegalovirus and Chlamydia trachomatis in the induction of cervical neoplasia in the mouse.

Cytomegalovirus and Chlamydia trachomatis are prevalent sexually transmissible pathogens. They produce persistent infections of the cervix and have been associated with cervical neoplasia. Cytomegalovirus has also been shown to induce transformation of cells in culture. Because of the high prevalence of genital infections with these pathogens and evidence that they may have oncogenic effects on the cervix, cytomegalovirus (strain AD-169) and C. trachomatis (serovar LGV-2) were tested for oncogenicity in a mouse model in which induction of cervical neoplasia by repeated exposure to inactivated herpes simplex viruses has been demonstrated previously. Cotton tampons, saturated with UV-inactivated cytomegalovirus, C. trachomatis, or corresponding control fluids, were inserted into the vaginas of virgin C57 mice 3 times a week. Smears of vaginal aspirates for cytological examination were obtained every 5 weeks. After 75-90 weeks of exposure, the mice were sacrificed and serial sections of their reproductive tracts were examined. Cervical dysplasia was detected by histological examination in 51% and cervical carcinoma in 10% of mice exposed to cytomegalovirus. In control mice, in contrast, dysplasia developed in 3% and carcinoma in none. The progression from normal cervical epithelium to dysplasia to carcinoma observed with cytomegalovirus exposure was similar to that observed previously in this model after exposure of mice to herpes simplex virus types 1 and 2. The frequencies of cervical abnormalities in mice exposed to C. trachomatis or corresponding control fluid were low, and differences between the two groups were not statistically significant. These data indicate that strain AD-169 of cytomegalovirus is oncogenic for the mouse cervix and suggest that the LGV-2 serovar of C. trachomatis is not.

Animals↗
PubMed1986

Nuclear deoxyribonucleic acid heterogeneity of ovarian borderline malignant serous tumors.

Sixteen borderline malignant serous ovarian tumors and seven well-differentiated invasive serous ovarian carcinomas were examined with the technique of Feulgen microspectrophotometry for the determination of nuclear deoxyribonucleic acid (DNA) ploidy patterns (diploid versus aneuploid) and ploidy levels of the stem cell lines. Of the nine stage I-II borderline malignant tumors, only one (11%) was aneuploid. In contrast, four of seven (57%) stage III borderline malignant neoplasms and all stage III carcinomas were aneuploid. The stem cell modal values in all borderline serous tumors were less than triploid (3N) while in five of seven carcinomas stem cell modal values were greater than triploidy. This contrast in ploidy patterns and ploidy levels may explain the differences in biologic behavior between borderline malignant serous tumors and invasive serous carcinomas of the ovary.

Adult↗
PubMed1983

Effect of prior immunization on induction of cervial cancer in mice by herpes simplex virus type 2.

Previous studies at this laboratory showed that repeated application of inactivated herpes simplex virus type 2 to the mouse cevix produced premalignant and malignant lesions. In the present study mice were inoculated with inactivated herpes simplex virus type 2 or control solution and Freund's adjuvant by intraperitoneal and subcuaneous routes before exposure of the cervix to inactivated virus. It appears that immunization with inactivated virus conferred a protection against the induction of cervical carcinoma.

Animals↗
PubMed1983

Cervical papillomavirus infection in diethylstilbestrol-exposed progeny.

Histologic sections from cervical and vaginal biopsies showing dysplasia in 37 women exposed to diethylstilbestrol (DES) in utero were stained for human papillomavirus structural antigens using an immunoperoxidase technique. Forty-three percent of the lesions had detectable papillomavirus antigens. These findings indicate that a significant proportion of cervical dysplasia observed in DES-exposed progeny is associated with papillomavirus infection.

Animals↗
PubMed1981

Induction of uterine cancer with inactivated herpes simplex virus, types 1 and 2.

A series of studies were performed to evaluate the oncogenic potential of inactivated herpes simplex viruses types 1 (HSV-1) and 2 (HSV-2) in the mouse cervix. HSV-1 or HSV-2 prepared in HEp-2 cell cultures and inactivated by exposure to formalin or ultraviolet light was applied to the mouse cervix for periods ranging from 20 to 90 weeks. Control mice were exposed for the same period to control fluids. Vaginal cytologic preparations from all animals were examined weekly to detect epithelial abnormalities. Animals were sacrificed and histopathological studies were carried out when cellular changes seen on vaginal smears resembled those indicative of premalignant or malignant changes as previously established in a similar model system using coal tar hydrocarbons. Other animals were exposed for periods up to 90 weeks, or until there was cellular evidence of invasive cancer. Cytologic and histologic materials were coded and evaluated without knowledge of whether they were from virus-exposed or control animals. Premalignant and malignant cervical lesions similar to those that occur in women were encountered in 78 to 90% of the virus-exposed animals. All controls were normal. Invasive cancer was detected in 24 to 60% of the animals and dysplasia was found in 18 to 66%. The yield of invasive cancer was twice as great after exposure to ultraviolet-inactivated HSV-2 as compared with formalin-inactivated virus. Various histologic grades of carcinoma of the cervix and endometrium were found. No primary lesions were found in the vagina or ovaries.

Adenocarcinoma↗
PubMed1979

Significance of squamous components in endometrioid carcinoma of the ovary.

Forty-nine cases of ovarian endometrioid carcinoma with squamous foci were reviewed. Of particular interest was the biologic behavior of the neoplasms in relation to the appearance of the epithelium. As previously noted for the analogous uterine endometrial tumors, the ovarian adenosquamous lesions occurred later in life, were more advanced, were associated with less differentiated adenocarcinomatous components, and had a poorer prognosis. The five-year survival rate for patients with adenosquamous endometrioid ovarian carcinoma was 21% in comparison with the 90% survival found in patients with ovarian endometrioid adenocanthoma.

Adenocarcinoma↗
PubMed1979

Nuclear DNA and histologic studies of genital lesions in diethylstilbestrol-exposed progeny. II. Intraepithelial glandular abnormalities.

This study has analyzed the nuclear DNA content of intraepithelial glandular lesions in diethylstilbestrol (DES)-exposed offspring. The endocervical cells and endometrial-tubal cells present in the vaginal adenosis and pericervical collars had a euploid distribution. However, greater proliferative activity was found among the endometrial-tubal cells. In the cells of vaginal adenosis of a postpartum woman without a confirmed history of maternal exposure to DES, a polyploid pattern was found, indicating that endometrial-tubal cells underwent hyperplastic changes under the influence of hormonal stimulation. In an atypical adenosis derived from endometrial-tubal cells, an aneuploid pattern was found. Based on these findings, it is suggested that endometrial-tubal cells have a greater proliferative potential than endocervical cells.

Adult↗
PubMed1977

Estrogen and endometrial carcinoma. An independent pathology review supporting original risk estimate.

Initial evidence suggested that estrogen therapy increases the risk of endometrial carcinoma. It was then suggested that some studies may have exaggerated the hazard of estrogen therapy by including patients with atypical endometrial hyperplasia among those having endometrial carcinoma. Three internationally recognized pathologists reviewed the histology slides available from the Ziel and Finkle study, which originally reported a risk ratio of 7.6 for estrogen users. At least one of the pathologists concurred with the original diagnosis in all but one case. Furthermore, all pathologists aggreed that 74 per cent (66/89) were correctly diagnosed. In the 66 patients with unanimous diagnosis, 61 per cent (40/66) had used conjugated estrogens, versus 57 per cent (54/94) in the original study. On the basis of 66 patients and 132 matched controls, the revised risk-ratio estimate is 8.1 (with a one-sided 95 per cent lower confidence limit of 4.5), validating the original estimate.

Biopsy↗
PubMed1975

Cellular detection of vaginal adenosis.

Cellular samples obtained by vaginal scrapings from 204 women exposed to diethylstilbestrol (DES) in utero were evaluated and compared with samples collected from a like number of controls. Several different sampling methods were evaluated. Vaginal scrapings contained columnar cells existing alone or in combination with squamous metaplastic cells and less frequently were characterized only by metaplastic cells. None of the control samples contained columnar cells and only 1 of 200 control samples contained metaplastic cells. The cellular findings in the offspring of women exposed to DES in utero varied in relation to age. Cellular abnormalities were demonstrated in 90.4% of women having scrapings of visible lesions and in 88.1% of women studied by 4-quadrant vaginal scrapings in the absence of clinical disease. Of 58 women with histopathologically proven adenosis, 57 (98.3%) had similar cellular abnormalities. Abnormalities were demonstrated in squamous epithelial cells of the vagina in 8 (3.9%) of the women exposed to DES in utero, and in 5 of these women there were similar changes in the uterine cervix. Only 2 (0.9%) of the women had cellular changes suggesting dysplasia of the vagina.

Adolescent↗