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Biomedical subjects

W A Peters

Publications and source records attributed to W A Peters.

At least 37 records · Page 2Linked to original sources
PubMed1991

A high-yield sampler for toxicological characterization of complex mixtures in combustion effluents.

Combustion sampling for toxicological assessment often requires that large (greater than 100 mg) lots of complex organic mixtures of wide volatility range be rapidly recovered from high temperature gases without contamination. A new sampler, meeting these criteria for studies of public health interest, has been developed and demonstrated. The device provides high sampling rates and intimate contacting of the samples stream with large volumes of a well-cooled, liquid solvent, dichloromethane (DCM). This promotes rapid organics dissolution from carrier gas and particulates and prompt dilution and quenching of the resulting solution, resulting in high organics collection efficiencies with minimal DCM losses. Solvent separation then remits large quantities of concentrated organics for chemical analysis and toxicological testing. One- to seven-hour interrogations of in-flame, post-flame, and flue gas regions gave 50- to 250-mg yields of complex organic mixtures. In side-by-side sampling of combustion exhaust, the DCM sampler provided higher yields of DCM solubles (identified with complex organic mixtures) and of S. typhimuirim mutagens (active without exogenous metabolizing agents) than did a filter/polymeric sorbent bed sampling train. The new sampler also collects polar and high volatile hydrocarbons such as benzaheyde, pentadiyne, m- and p-diethynyl-benzene, and 1-hexen-3,5-diyne. Nitration of naphthalene and pyrene in DCM solution (1 mg/mL each) was less than 1 part in 10(7) after a 345-min exposure to a bubbling flow of moist N2/air mixture (1:1 v/v) containing 107 ppm NO and 1.5 ppm NO2, indicating that for these condition a DCM sampler should resist artifactual nitration of aromatics. However, because of the very high bacterial mutagenicity of some nitroaromatics and the wide range of sampling conditions of environmental interest, nitration and all artifacts must still be scrutinized when using the DCM sampler. The DCM sampler is expected to contribute to public health impact assessments by facilitating detailed determinations of the identities, compositions, concentrations, sources, formation mechanisms, and biological activity of environmental toxicants in gaseous atmospheres.

Atmospheric Pressure↗
PubMed1990

Invasive cervical cancer treated initially by standard hysterectomy.

Ninety-two patients with invasive cervical cancer initially treated by standard hysterectomy were evaluated for features related to survival. The cell type included squamous cell (64) and adenocarcinoma (28). Posthysterectomy therapy included radiation therapy (78), pelvic lymphadenectomy (3), and radical parametrectomy (1). Hysterectomy was initially performed for the following indications: invasive lesion missed on cone biopsy, 17; hemorrhage at cone biopsy, 2; bleeding, 16; abnormal cytology, 13; presumed endometrial cancer, 9; known cancer, 7; pelvic relaxation, 5; planned therapy, 3; fibroids, 3; adnexal mass, 2; chronic discharge, 1; pyometra, 1; postpartum endometritis, 1. The cumulative 5-year survival for all patients was 68%, for squamous cell 80%, and for adenocarcinoma 41% (P = 0.0001). On postoperative evaluation 84 patients had presumed Stage I and 7 had parametrial involvement (Stage II). Patients with Stage I disease were then examined separately by cell type. Fifty-seven patients with squamous cell disease had cumulative 5-year survival of 85%. Radiation therapy in the immediate postoperative period produced a survival of 88%, compared to observation only with a 69% survival (P = .10). Patients with squamous cell disease and more than 50% cervical invasion had a 75% survival compared to a 96% survival for those with less than 50% (P = .02). The presence of disease at the surgical margins, grade, age, and increase in radiation therapy did not influence survival. Twenty-seven patients with presumed Stage I adenocarcinoma had a cumulative 5-year survival rate of 42%. Survival was significantly influenced by tumor grade (P = .018) and the amount of postoperative radiation therapy (P = .03), while age, amount of residual tumor, and presence of tumor at surgical margins did not influence survival. Patients with invasive squamous cell carcinoma treated by standard hysterectomy and postoperative radiation therapy have a prognosis similar to those treated initially by either radical surgery or radiation therapy. Patients with adenocarcinoma appear to have a significantly decreased survival when compared to patients with squamous cell disease and their prognosis is related to tumor grade and the amount of postoperative pelvic radiation.

Adenocarcinoma↗
PubMed1990

Prolapse of a neovagina created by self-dilatation.

In patients with congenital absence of the vagina, a neovagina may be created by either operative or nonoperative techniques. A 25-year-old patient with a neovagina created by self-dilatation developed complete prolapse of the neovagina with an enterocele. A transabdominal sacral colpopexy successfully suspended the vaginal vault and allowed the patient to resume sexual function.

Adult↗
PubMed1989

Results of chemotherapy in advanced carcinoma of the fallopian tube.

Forty-six patients with measurable disease received chemotherapy for advanced primary or recurrent carcinoma of the fallopian tube. The response rate was 9% with single-agent therapy, 29% with multiagent therapy without cisplatin, and 81% with cisplatin-containing combination therapy. Survival was significantly improved in Stage III/IV with the addition of cisplatin-based combination therapy.

Adult↗
PubMed1989

Cisplatin and adriamycin combination chemotherapy for uterine stromal sarcomas and mixed mesodermal tumors.

Twenty-eight patients with a uterine stromal sarcoma or mixed mesodermal tumor were treated with cisplatin 100 mg/m2 and Adriamycin 45-60 mg/m2, given with intravenous hydration every 3 to 4 weeks. Group I consists of 11 patients with measurable disease following initial surgery or with a recurrence. Eight of the eleven evaluable patients with measurable disease had a response (73%), and three of these patients have had a negative second-look procedure, and two are alive and disease free more than 24 months after initiation of treatment. Group II consists of 17 patients treated with adjuvant chemotherapy after primary surgery. The patients were selected for adjuvant therapy based on previous established poor prognostic features. Of the 17 patients in group II, 14 had invasion of the outer one-third of the myometrium and the other three had invasion to the middle one-third. Seven had documented positive pelvic and/or periaortic lymph nodes and five had positive peritoneal washings. With a median follow-up of 34 months, there have been only four recurrences in group II. Two of the recurrences occurred in patients who discontinued therapy after only two cycles of chemotherapy. There is a projected 5-year survival of 75% in these high-risk patients. Of the seven patients with documented nodal involvement, one patient died with a recurrence at 23 months, one patient died from a perforated diverticulum, and the other five are alive and disease free with a median follow-up of 36 months (34-90 months). Two patients with multiple positive nodes are disease free at more than 5 years. Combination chemotherapy with cisplatin and Adriamycin has a high response rate with advanced measurable disease and improves survival in high-risk patients who receive it as adjuvant therapy.

Adult↗
PubMed1989

Platinum-based combination chemotherapy for malignant mixed mesodermal tumors of the ovary.

Although considerable clinical data are available to guide treatment decisions for patients with ovarian epithelial malignancies, therapy for the rare malignant mixed mesodermal (mullerian) tumor (MMMT) of the ovary is poorly studied. Ten untreated patients diagnosed with primary ovarian MMMT were managed with cis-platinum-based combination chemotherapy from 1980 to 1985. Six of the 10 patients were stage III suboptimal with evaluable residual disease; 4 of these 6 had CRs with a median duration of response of 13 months. The remaining 2 patients had PRs, of 2 and 11 months duration. Four patients had stage III optimal disease; 1 progressed at 7 months, 1 progressed at 16 months and the other 2 patients have no clinical evidence of disease at 12+ and 22+ months. Despite impressive initial response rates, survival overall was poor, with a median survival for all 10 patients of 16+ months.

Adult↗
PubMed1989

Small cell carcinoma of the vagina with neuroendocrine features. A report of three cases.

Three patients were treated for primary small cell carcinoma of the vagina. The light microscopic features were similar to those of small cell carcinoma of the lung, cervix and endometrium. Electron microscopy revealed occasional cytoplasmic, neurosecretory-type granules and cytoplasmic processes, features consistent with neuroendocrine cells. Radiotherapy appears to provide local control, but widespread disease at presentation or early metastases suggest the use of adjuvant chemotherapy in the initial management of the neoplasm.

Adult↗
PubMed1988

Accuracy of office and operating room curettage in the grading of endometrial carcinoma.

This retrospective study reviewed the records of 375 patients with clinical stage I adenocarcinoma of the endometrium. After criteria for exclusion were applied, 223 patients were analyzed further. Results from office and operating room curettage were compared with findings at hysterectomy. Twenty percent of cases showed an increase in grade at hysterectomy after office curettage; 15% showed upgrading after operating room curettage, a nonsignificant difference. We conclude that the techniques have equivalent accuracy in the determination of tumor grade. However, despite their well-documented reliability in tumor detection, a 15-20% upgrade suggests that frozen section confirmation of grade and depth of invasion in the hysterectomy specimen may be necessary if further surgical staging is not already planned.

Adenocarcinoma↗
PubMed1988

Prognostic features of carcinoma of the fallopian tube.

One hundred fifteen women with carcinoma of the fallopian tube were examined in this retrospective review. A third of the patients were nulliparous and 37% had evidence of old pelvic inflammatory disease. The most common symptoms were bleeding, pain, and/or vaginal discharge. Prognostic factors that predicted death from tumor were the presence of extratubal disease at initial surgery and the bulk of residual tumor left after the initial surgery. With disease limited to the fallopian tube, the depth of invasion of the tubal wall was correlated with the risk of treatment failure. Among patients with disease limited to their fallopian tubes, there was no statistically significant improvement in survival with the addition of either pelvic irradiation or single-agent chemotherapy. Among women with extrapelvic disease, survival improved significantly with the use of cis-platinum-containing multiagent chemotherapy.

Adult↗
PubMed1987

Chemical and toxicological characterization of residential oil burner emissions: I. Yields and chemical characterization of extractables from combustion of No. 2 fuel oil at different Bacharach Smoke Numbers and firing cycles.

Particulates and complex organic mixtures were sampled from the exhaust of a flame retention head residential oil burner combusting No. 2 fuel oil at three firing conditions: continuous at Bacharach Smoke No. 1, and cyclic (5 min on, 10 min off) at Smoke Nos. 1 and 5. The complex mixtures were recovered by successive Soxhlet extraction of filtered particulates and XAD-2 sorbent resin with methylene chloride (DCM) and then methanol (MeOH). Bacterial mutagenicity [see Paper II (8)] was found in the DCM extractables. Samples of DCM extracts from the two cyclic firing conditions and of the raw fuel were separated by gravity column chromatography on alumina. The resulting fractions were further characterized by a range of instrumental methods. Average yields of both unextracted particulates and of DCM extractables, normalized to a basis of per unit weight of fuel fired, were lower for continuous firing than for cyclic firing. For cyclic firing, decreasing the smoke number lowered the particulates emissions but only slightly reduced the average yield of DCM extractables. These and similar observations, here reported for two other oil burners, show that adjusting the burner to a lower smoke number has little effect on, or may actually increase, emissions of organic extractables of potential public health interest. Modifications of the burner firing cycle aimed at approaching continuous operation offer promise for reducing the amount of complex organic emissions. Unburned fuel accounted for roughly half of the DCM extractables from cyclic firing of the flame retention head burner at high and low smoke number. Large (i.e., greater than 3 ring) polycyclic aromatic hydrocarbons (PAH) were not observed in the DCM extractables from cyclic firing. However, nitroaromatics, typified by alkylated nitronaphthalenes, alkyl-nitrobiphenyls, and alkyl-nitrophenanthrenes were found in a minor subfraction containing a significant portion of the total mutagenic activity of the cyclic low smoke samples (8). Oxygen-containing PAH, typified by phenalene-1-one and its alkyl derivatives, are important mutagens from cyclic firing at high smoke conditions. Thus, oil burner effluents differ markedly from those of several other combustors, including the automotive diesel engine, where multiring PAH, typified by fluoranthene and alkylated phenanthrenes, account for a significant portion of the effluent mutagenicity. Implications for combustion and emissions source identification are discussed.

Air Pollutants↗
PubMed1987

Tuboovarian sigmoid fistula after cesarean section. A case report.

Tuboovarian sigmoid fistulae are rare complications of pelvic inflammatory disease. A 31-year-old woman had a severe post-cesarean-section infection that formed a tuboovarian abscess and ruptured into the sigmoid colon. The abscess and subsequent fistula led to persistent pain and purulent diarrhea. A salpingo-oophorectomy with closure of the colon was performed. The patient was still asymptomatic 20 months after the surgery.

Abscess↗
PubMed1986

CA-125. Use as a tumor marker with mixed mesodermal tumors of the female genital tract.

CA-125 levels were determined in seven patients with a mixed mesodermal tumor of the ovary or endometrium. An elevated level was detected in five of six patients with metastatic or recurrent disease. Chemotherapy with cisplatin and Adriamycin (doxorubicin) resulted in a response in four patients, and the CA-125 level correlated well with the clinical status of the disease. Cisplatin/Adriamycin is an active combination in mixed mesodermal tumors and CA-125 appears to be a useful marker for following therapy.

Aged↗
PubMed1986

Salvage therapy with whole-abdominal irradiation in patients with advanced carcinoma of the ovary previously treated by combination chemotherapy.

Whole-abdominal irradiation was delivered to 22 patients with epithelial carcinoma of the ovary who had persistent disease after chemotherapy. Seventeen patients were treated with an open whole-abdominal field and 5 with the moving-field technique. Eleven of the 22 also received a pelvic boost. Two of nine patients with microscopic disease at second look are alive and disease-free at 34 and 52 months, respectively. There were no salvages among the patient with macroscopic disease. Major complications included bowel obstruction in three patients and radiation enteritis in one patient. Whole-abdominal irradiation is not an effective salvage regimen after multiagent chemotherapy.

Abdomen↗
PubMed1985

Microinvasive carcinoma of the vagina: a distinct clinical entity?

Six patients with superficially invasive squamous carcinoma of the vagina are described. All had less than 2.5 mm of invasion as measured from the surface, lacked involvement of the lymph-vascular spaces, and arose within a field of carcinoma in situ. Three of the six had previously been treated for carcinoma of the cervix. The patients with microinvasive carcinoma had a median age 10 years younger than that of patients with Stage I carcinoma of the vagina. Treatment of the six patients has been by partial or total vaginectomy. With follow-up of 51 to 172 months, there have been no recurrences. More experience is needed to define microinvasive squamous carcinoma of the vagina and to determine the optimal treatment for these lesions.

Adult↗
PubMed1985

Carcinoma of the vagina. Factors influencing treatment outcome.

A 33-year review from the University of Michigan Medical Center of 86 cases of primary carcinoma of the vagina included 68 squamous carcinomas, 13 adenocarcinomas, and 5 small cell carcinomas. There was a 26% incidence of prior cervical carcinoma and a 21% incidence of prior pelvic radiation therapy. The median interval between the diagnosis of invasive cervical and vaginal carcinoma was 20 years. Survival was strongly correlated with stage. There was no association between survival and involvement of a particular vaginal segment or the amount of vaginal surface area involved with tumor. Irradiation was the most frequently employed primary therapy for vaginal carcinoma. Local control was correlated with the mid-tumor irradiation dose, with predictable control obtained only with doses above 7500 rad. The use of interstitial therapy should facilitate local control without increasing the complication rate.

Adenocarcinoma↗
PubMed1985

Primary sarcoma of the adult vagina: a clinicopathologic study.

Combination chemotherapy has dramatically improved the results of treatment for embryonal rhabdomyosarcoma of the vagina in children, but little attention has been directed toward vaginal sarcomas in adults. This report of 17 cases of primary sarcoma of the adult vagina includes ten leiomyosarcomas, four mixed mesodermal tumors, one undifferentiated sarcoma, one stromal sarcoma, and one neurofibrosarcoma. The leiomyosarcomas, mixed mesodermal tumors, and the stromal sarcoma were morphologically similar to their uterine counterparts. Thirty-five percent of the patients had received pelvic irradiation for carcinoma of the cervix. Three of four patients treated by pelvic exenteration are alive and disease free after 84 to 161 months of observation. All 13 patients who received other forms of primary therapy died of recurrence. The pelvis was the first site of recurrence in all treatment failures and the only site of failure in 50%.

Adenocarcinoma↗
PubMed1985

Pregnant women's absorption of iron from prenatal supplements.

A randomized, double-blind, crossover study was carried out on iron absorption from three prenatal supplements by women in the first trimester of pregnancy. The supplements were given to fasting subjects as a single pill early in the morning, and iron absorption was determined from measurements of serum iron performed during the course of the day. Iron absorption from two of the supplements was substantially less than the 3.5 mg recommended for the prevention of iron deficiency during pregnancy. The third supplement, containing reduced amounts of calcium and magnesium, provided on the average 3.6 mg of absorbed iron to the subjects. These results support previous findings in nonpregnant subjects that the availability of iron in a prenatal supplement is affected by the overall composition of the supplement.

Adult↗