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Biomedical subjects

J Boyce

Publications and source records attributed to J Boyce.

At least 55 records · Page 3Linked to original sources
PubMed1987

Phase partitioning in space and on earth.

In aqueous solution at low concentrations, the neutral polymers dextran and poly(ethylene glycol) (PEG) rapidly form a two-phase system consisting of a PEG-rich phase floating on top of a dextran-rich phase. Biological particles and macromolecules tend to partition differentially between the phases and the liquid-liquid phase interface in these systems. Bioparticle partitioning has been shown to be related to physiologically important surface properties such as membrane charge or lipid composition. Affinity partitioning into the PEG-rich phase can be accomplished by coupling PEG to a ligand having affinity for specific cells or macromolecules. Subpopulations can be identified or separated using multi-step countercurrent distribution (CCD). Incomplete understanding of the influence of gravity on the efficiency and quality of the impressive separations achievable by partitioning, and appreciation for the versatility of this efficient technique, have led to its study for low-gravity biomaterials processing. On Earth, two-phase systems rapidly demix because of density differences between the phases. In low-gravity, demixing has been shown to occur primarily by coalescence. Polymer surface coatings, developed to control localization of demixed phases in low-g, have been found to control electroosmosis which adversely affects electrophoretic separation processes on Earth and in space. In addition PEG-derivatized antibodies have been synthesized for use in immunoaffinity cell partitioning.

Dextrans↗
PubMed1987

A study to examine any difference in absorption of cod-liver oil when taken fasting compared to during a meal by examining changes in blood lipid levels.

Healthy volunteers (two male and three female in each group) took cod-liver oil supplements in either the fasting (before breakfast) or fed (with lunch) state for 14 days. After a 14-day break the groups treatments were reversed. Blood pressure and pulse were monitored and blood samples analysed for total lipid, total and HDL cholesterol at 2-weekly intervals. One male and one female volunteer acted as controls, having measurements taken but no blood samples. No changes in pulse rate or blood pressure or clotting times were noted, but the ratio of HDL cholesterol to total cholesterol changed in different directions according to time of consumption in those consuming cod-liver oil.

Absorption↗
PubMed1985

Complications of combined surgery and radiation therapy for carcinoma of the endometrium.

Long-term gastrointestinal (GI) and urinary tract (UT) complications were evaluated in 133 women with carcinoma of the endometrium who were treated by both radiotherapy and hysterectomy. Major complications developed in 8% of patients who received external pelvic radiation but in none with intracavitary radiation. GI complications were more frequent and more severe in patients receiving external pelvic radiation than in those who received only intracavitary radiotherapy, irrespective of the sequence of treatment. UT complications were more frequent with prehysterectomy external radiotherapy (N = 39) than with posthysterectomy external radiotherapy (N = 21).

Brachytherapy↗
PubMed1985

Prognostic factors in malignant mesodermal (mullerian) mixed tumors of the uterus.

Clinicopathologic studies of 16 homologous and 19 heterologous malignant mesodermal (Mullerian) mixed tumors of the corpora uteri showed that homologous tumors were more common in black women than in white women; in the former, tumors were diagnosed at a younger age and in more advanced stages than in the latter. Fifty-five percent of women with clinical stage I disease had a higher surgicopathologic stage. The most significant prognostic factors were pathologic extent of disease and vascular invasion in the myometrium. There was no difference in outcome between homologous and heterologous tumors. Initial surgery for staging is essential for the adequate evaluation and treatment of these patients.

Aged↗
PubMed1985

Prognostic factors in carcinoma of the vulva.

The clinical and pathologic characteristics of epidermoid carcinoma of the vulva in 84 women treated by vulvectomy were evaluated in relation to inguinal node status and survival. Tumor diameter, depth of invasion, clinical node status, vascular invasion, and pattern of invasion were all individually correlated with the pathologic status of the inguinal nodes. However, when evaluated in combination, only the clinical status of the inguinal nodes, the depth of invasion, and the pattern of invasion (in this order of significance) were predictive of pathologic inguinal node status. Tumor diameter, inguinal node status, depth of invasion, pattern of invasion, and vascular invasion were individually correlated with survival. When evaluated in combination, the clinical diameter of the lesion was the most important predictor of survival; depth of invasion and vascular invasion contributed additional information.

Carcinoma, Squamous Cell↗
PubMed1984

The relationship between human papillomavirus and lower genital intraepithelial neoplasia in immunosuppressed women.

In a group of 20 immunosuppressed women with lower genital neoplasia, evidence of associated human papillomaviral infection was found in all patients on the basis of the histologic identification of koilocytes in the upper strata of areas of mild or moderate dysplasia. Immunohistochemical study of similar areas disclosed human papilloma structural antigens in the lesions in 60%, while 50% had lesions in which human papilloma virions were detected by the electron microscope. An abnormal immunologic status, indicated by an altered T-helper/T-suppressor ratio, a deficient response to mitogenic stimulation, or both, was confirmed in 80% of the patients studied. Twelve of the 20 patients had unusually persistent and recurrent intraepithelial neoplasia, and in one the disorder progressed to invasive epidermoid carcinoma. The progressive behavior of human papillomavirus-associated neoplasia in these immunosuppressed patients might represent an accelerated version of the long-term course of such lesions in immunocompetent hosts.

Adolescent↗
PubMed1984

Inhibition of lymphocyte mitogenesis by factor(s) released from macrophages isolated from ascitic fluid of advanced ovarian cancer patients.

Ascitic fluid from women with advanced ovarian carcinomas was shown to contain factor(s) which inhibit(s) T lymphocyte mitogenesis. The factor(s) was (were) demonstrated to be associated with the infiltrating macrophages. The inhibition was reversible and inhibited mitogenesis at some late event in the cell cycle. The inhibitory substance(s) was (were) noncytotoxic, dialyzable, heat-stable at 70 degrees C for 10 min (but unstable at 100 degrees C for 15 min), and partially resistant to protease treatment (55%-70%). Further experiments demonstrated that macrophages isolated from the ascitic fluid of patients with cirrhosis of the liver also released factor(s) which inhibit(s) T lymphocyte mitogenesis. On the basis of our data and data from other investigators, we propose that in advanced human ovarian cancer of epithelial origin, macrophages which infiltrate the ascitic fluid elaborate nonspecific inhibitors of T lymphocyte blastogenesis within the proximal environment, resulting in localized immunosuppression and the subsequent enhancement of metastasis within the peritoneal cavity, the tumor cells themselves being resistant to the cytocidal action of the macrophages due to genetic selection and/or their inherent biochemical ability to circumvent normal immunosurveillance mechanisms. This may account, at least in part, for the rapid metastasis and poor prognosis of human ovarian adenocarcinomas.

Adenocarcinoma↗
PubMed1983

Effective chemotherapy for advanced carcinoma of the cervix with bleomycin, cisplatin, vincristine, and methotrexate.

This study was designed as a Phase II clinical trial in advanced recurrent or metastatic squamous cell carcinoma of the cervix with a combination of bleomycin (B: 10 u/m2/d) and cisplatin (P: 20 mg/m2/d) administered for five consecutive days in intravenous infusion for 7 hours and vincristine (V: 1 mg/m2) and methotrexate (M: 40 mg/m2) administered only on day one of each cycle which was repeated every 28 days up to a maximum of 6 times. Over a period of 2 years, 15 evaluable patients with measurable disease received at least 3 courses of therapy. Six had recurrent disease and nine had distant metastases. All had previous radiation therapy. There were two dropouts after the first course due to nausea and vomiting which was practically universal. Other side effects included: mild paresthesias of the extremities (89%), stomatitis (41%), diarrhea (17%), moderate pancytopenia and hypomagnesemia which was reduced from 65% to 17% when magnesium sulfate 10% was administered with cisplatin. Sixty-six percent of the evaluable patients achieved remission (7 partial and 3 complete) usually before the fourth course of therapy. The disease-free interval was of 29.7 +/- 15 weeks in all responders (40.6 +/- 15.5 weeks in complete responders). The mean survival from the start of BPVM therapy was of 55.8 +/- 33.3 weeks in responders and of only 14 +/- 2.9 weeks in nonresponders (P less than 0.01). It is concluded that BPVM is an effective combination chemotherapy in advanced squamous cell carcinoma of the cervix. These results should be confirmed in a Phase III trial.

Adult↗
PubMed1983

Association of human papillomavirus infection with cervical intraepithelial neoplasia.

Human papillomavirus infections of the cervix were assessed in patients attending a colposcopy clinic. Of 348 patients with cervical biopsies, 134 (38.5%) had human papillomavirus infections, and of 251 patients with cervical intraepithelial neoplasia (CIN) 112 (44.6%) had human papillomavirus. The majority of patients with human papillomavirus had concurrent CIN (83.6%; 112/134). Patients with human papillomavirus were significantly younger than patients without human papillomavirus (24.4 versus 29.9 years mean age; P less than .001), had significantly milder degrees of CIN (84% versus 43% mild/moderate dysplasia; P less than .001), and had a significantly lower mean number of pregnancies (2.16 versus 3.05; P less than .001). A matched pairs analysis of 69 pairs showed the same distribution of CIN in both human papillomavirus and nonhuman papillomavirus patients. Electron microscopy of human papillomavirus--specific koilocytes confirmed the presence of human papillomavirus particles in the nuclei.

Adult↗
PubMed1981

Prognostic factors in cervical carcinoma: implications in staging and management.

Individualization of treatment using judicious combinations of external and intracavitary irradiation remains the cornerstone of the radiation management of carcinoma of the cervix. The inherent propensity of this cancer to either confine itself to the pelvis or else spread in a systematic and predictable manner through lymphatic channels has facilitated its therapeutic control. The treatment of most early invasive cervical carcinomas is equally advantageous using either intracavitary radium or surgery. However, certain Stage I patients have morphologic and histologic characteristics that militate against tumor control. Factors such as tumor size, depth of invasion, vascular infiltration, uterine extension, and barrel-shaped presentation affect the course of the disease and survival. A clinical-pathologic staging for cervical carcinoma incorporating the above mentioned factors into the current clinical FIGO staging system has been suggested. It aims to facilitate the recognition of those early tumors that require additional external radiotherapy. A description of the role of surgery, intracavitary and external radiation, and their combinations is included. In advanced carcinoma of the cervix, failure can be attributed to either large tumors containing cores of hypoxic cells resistant to conventional radiation therapy or to uncontrolled subclinical disease in the lymphatics at or near the border of the irradiated area. Radiotherapy combined with surgery, oxygen enhancers, infusion chemotherapy, and large particle high LET radiation has been implemented to increase local control; for distal failures, extended field irradiation of paraaortic nodes has been found to be technically feasible and well tolerated and is being studied for its effects on increased survival. The rationale for newer treatment procedures, including preliminary results and their complications, is discussed.

Antineoplastic Agents↗
PubMed1981

The significance of atypical vessels and neovascularization in cervical neoplasia.

The relationship between atypical vessels seen colposcopically and dysplasia, carcinoma in situ (CIS), microinvasion, and frank invasion was studied quantitatively. No atypical vessels were found with dysplasia, but 2.8% of patients with CIS had atypical vessels. Half of the patients with microinvasion and all of the patients with frank invasion, in whom the entire zone of transformation was viewed, had atypical vessels. Eight-two percent of the patients with atypical vessels had invasion. The conclusions are: (1) Atypical vessels are not present with dysplasia and rarely present with CIS. (2) Atypical vessels may be associated with microinvasion, but are required for frank invasion to occur. (3) Because atypical vessels are usually associated with invasion, which can be in or near the field of atypical vessels, diagnosis cone biopsy should be performed if atypical vessels are seen and colposcopic biopsies do not show frank invasion. (4) Microinvasion without atypical vessels may be a localized disease.

Adult↗
PubMed1981

Postreplication repair in Saccharomyces cerevisiae.

Postreplication events in logarithmically growing excision-defective mutants of Saccharomyces cerevisiae were examined after low doses of ultraviolet light (2 to 4 J/m2). Pulse-labeled deoxyribonucleic acid had interruptions, and when the cells were "chased," the interruptions were no longer detected. Since the loss of interruptions was not associated with an exchange of pyrimidine dimers at a detection level of 10 to 20% of the induced dimers, we concluded that postreplication repair in excision-defective mutants (or leaky mutants) does not involve molecular recombination. Pyrimidine dimers were assayed by utilizing the ultraviolet-endonuclease activity in extracts of Micrococcus luteus and newly developed alkaline sucrose gradient techniques, which yielded chromosomal-size deoxyribonucleic acid after treatment of irradiated cells.

DNA Repair↗