Pharmacological stress thallium scintigraphy with 2-cyclohexylmethylidenehydrazinoadenosine (WRC-0470). A novel, short-acting adenosine A2A receptor agonist

BACKGROUND

Pharmacological stress imaging with adenosine or dipyridamole is associated with a high incidence of side effects, including hypotension, chest pain, AV conduction abnormalities, and bronchospasm. Although the desired coronary vasodilatory response is mediated primarily by the adenosine A2A receptors, these side effects result from stimulation of the A1, A2B, or A3 adenosine receptors. We hypothesized that a selective adenosine A2A receptor agonist would induce coronary vasodilatation appropriate for pharmacological stress imaging, without evoking adenosine receptor-mediated side effects.

METHODS AND RESULTS

Infusions of a potent and selective A2A adenosine receptor agonist, WRC-0470 (0.1 to 3 micrograms kg-1. min-1 for 10 minutes), to five open-chest dogs produced dose-related left anterior descending (LAD) and left circumflex (LCx) coronary artery vasodilatation without altering mean arterial pressure, heart rate, left atrial pressure, or left ventricular dP/dt. In the same dogs, adenosine (300 micrograms . kg-1. min-1 for 4 minutes) produced coronary vasodilatation that was limited by significant hypotension. To determine the utility of WRC-0470 for pharmacological stress imaging, the hemodynamic responses to WRC-0470 (0.6 microgram.kg-1.min-1 for 10 minutes) and adenosine (250 micrograms.kg-1.min-1 for 4 minutes) were compared in dogs with critical LAD stenoses. 201T1 was injected at the peak WRC-0470 stress response. WRC-0470 increased LCx flow nearly fivefold but did not significantly lower mean arterial pressure. Anteroseptal defects were readily apparent in slice images from all dogs. The mean defect ratio (LAD/LCx) was 0.59 +/- 0.06.

CONCLUSIONS

The potent A2A-selective adenosine receptor agonist WRC-0470 is a short-acting coronary vasodilator with potential utility for pharmacological stress perfusion imaging.

Case-control study of endogenous steroid hormones and endometrial cancer

BACKGROUND

It has been suggested that identified risk factors for endometrial cancer operate through a single etiologic pathway, i.e., exposure to relatively high levels of unopposed estrogen (estrogen in the absence of progestins). Only a few studies, however, have addressed this issue directly.

PURPOSE

We assessed the risk of developing endometrial cancer among both premenopausal and postmenopausal women in relation to the circulating levels of steroid hormones and sex hormone-binding globulin (SHBG). The independent effect of hormones was assessed after adjustment for other known risk factors.

METHODS

The data used in the analysis are from a case-control study conducted in five geographic regions in the United States. Incident cases were newly diagnosed during the period from June 1, 1987, through May 15, 1990. The case patients, aged 20-74 years, were matched to control subjects by age, race, and geographic region. The community control subjects were obtained by random-digit-dialing procedures (for subjects 20-64 years old) and from files of the Health Care Financing Administration (for subjects > or = 65 years old). Additional control subjects who were having a hysterectomy performed for benign conditions were obtained from the participating centers. Women reporting use of exogenous estrogens or oral contraceptives within 6 months of interview were excluded, resulting in 68 case patients and 107 control subjects among premenopausal women and 208 case patients and 209 control subjects among postmenopausal women. The hormone analyses were performed on blood samples obtained from case patients or from hysterectomy control subjects before surgery. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by use of an unconditional logistic regression analysis after we controlled for matching variables and potential confounders. All P values were two-sided.

RESULTS

High circulating levels of androstenedione were associated with 3.6-fold and 2.8-fold increased risks among premenopausal and postmenopausal women, respectively, after adjustment for other factors (P for trend = .01 and < .001, respectively). Risks related to other hormone fractions varied by menopausal status. Among postmenopausal women, a reduced risk was associated with high SHBG levels and persisted after adjustment was made for obesity and other factors (OR = 0.51; 95% CI = 0.27-0.95). High estrone levels were associated with increased risk (OR = 3.8; 95% CI = 2.2-6.6), although adjustment for other risk factors (particularly body mass index) diminished the effect (OR = 2.2; 95% CI = 1.2-4.4). Albumin-bound estradiol (E2), a marker of the bioavailable fraction, also remained an important risk factor after adjustment was made for other factors (OR = 2.0; 95% CI = 1.0-3.9). In contrast, high concentrations of total, free, and albumin-bound E2 were unrelated to increased risk in premenopausal women. In both premenopausal and postmenopausal groups, risks associated with obesity and fat distribution were not affected by adjustment for hormones.

CONCLUSION

High endogenous levels of unopposed estrogen are related to increased risk of endometrial cancer, but their independence from other risk factors is inconsistent with being a common underlying biologic pathway through which all risk factors for endometrial cancer operate.

IMPLICATIONS

Further research should focus on alternative endocrinologic mechanisms for risk associated with obesity and body fat distribution and for the biologic relevance of the increased risk associated with androstenedione in both premenopausal and postmenopausal disease.

Differences between black and white patients with cancer of the uterine corpus in interval from symptom recognition to initial medical consultation (United States)

To determine whether Black women with symptoms of uterine corpus cancer had longer times from symptom recognition to initial medical consultation than did White women in the United States, 331 newly diagnosed patients living in Atlanta (GA), New Orleans (LA), and San Francisco/Oakland (CA) during 1985-87 were interviewed to collect information on symptoms, dates of recognition and consultation, and other factors that might affect the interval. Data were analyzed to estimate medical consultation rates and rate ratios following symptom recognition. Median recalled times between symptom recognition and consultation were 16 days for Black women and 14 days for White women. Although poverty, having no usual source of healthcare, and other factors were associated with lower consultation rates, the adjusted rate among Black women was only somewhat lower (0.87) than among White women, and the 95 percent confidence interval (CI = 0.58-1.31) was consistent with no true difference between the races. In addition, the median time to consultation for women with stage IV cancer was only 15 days longer than the time (14 days) for the women with stage I cancer. These results suggest that time from symptom recognition to initial medical consultation does not contribute importantly to the more advanced stage cancer of the uterine corpus commonly found among Black women.

Characterization of 8-(N-methylisopropyl)amino-N6-(5'-endohydroxy- endonorbornyl)-9-methyladenine (WRC-0571), a highly potent and selective, non-xanthine antagonist of A1 adenosine receptors

Previous studies in our laboratory identified N6-endonorbornyl-9-methyladenine (N-0861) as a highly selective (100-fold) A1-adenosine receptor antagonist (KB = 500 nM). However, its moderate potency limits the degree of A1-receptor blockade that can be achieved by systemically administered N-0861. Structure activity studies were undertaken to invent a compound that had greater affinity for the A1-adenosine receptors than N-0861. C8-N-methylisopropylamino-N6-5'-endohydroxy-N-0861 (WRC-0571) inhibited [3H]-N6-cyclohexyladenosine (CHA) binding to guinea pig A1-receptors with a Ki value of 1.1 nM. WRC-0571 was 200-fold less potent at inhibiting [3H]-5'-N-ethylcarboxamidoadenosine binding to bovine A2a receptors (Ki = 234 nM). WRC-0571 also inhibited the binding of radioligands to cloned human A1, A2a and A3 adenosine receptors with affinities of 1.7, 105 and 7940 nM, respectively. Thus in human adenosine receptors, WRC-0571 is 62-fold selective for the A1 vs. A2a and 4670-fold selective for the A1 vs. A3 receptors; WRC-0571 is therefore the most A1 vs. A3 selective compound yet described. In guinea pig isolated atria, WRC-0571 antagonized the A1-mediated negative inotropic responses to 5'-N-ethylcarboxamidoadenosine (NECA) with a KB of 3.4 nM. WRC-0571 was more than 2500-fold less potent at antagonizing NECA-induced A2b-mediated relaxation in guinea pig aorta. In anesthetized rats WRC-0571 antagonized adenosine-induced bradycardia at concentrations as low as 1 nmol/kg but failed to antagonize A2-mediated hindquarter vasodilation at concentrations up to 10,000 nmol/kg. WRC-0571 is orally active at concentrations as low as 0.3 mumol/kg. WRC-0571 is therefore a highly potent, highly selective antagonist of A1-adenosine receptors both in vitro and in vivo.

Chemotherapy, early surgical reassessment, and hyperfractionated abdominal radiotherapy in stage III ovarian cancer: results of a gynecologic oncology group study

PURPOSE

To determine outcomes and treatment toxicities in patients with optimal (< or = 1 cm residual) Stage III ovarian carcinoma treated with three courses of cisplatin-cyclophosphamide, surgical reassessment (SRA), and hyperfractionated whole abdominal irradiation (WAI).

METHODS AND MATERIALS

Forty-two eligible patients entered this prospective Phase II study conducted by the Gynecologic Oncology Group (GOG). Disease characteristics were as follows: age range, 32-76 years (median 58); Stage IIIA (n = 1, 2%), IIIB (n = 2, 5%), IIIC (n = 39, 93%); histology-serous papillary (n = 21, 50%); other (n = 21, 50%); Grade 1 (n = 1, 2%); 2 (n = 14, 33%); 3 (n = 27, 54%); residual disease after initial surgery (present: n = 23, 55%; absent: n = 19, 45%). Five patients progressed while on chemotherapy, could not be effectively cytoreduced, and were not eligible for WAI. Of the remaining 37 patients, 35 received WAI. Surgical reassessment was not performed in five patients.

RESULTS

Of 37 patients with known SRA status after chemotherapy, 21 (57%) were grossly positive, 4 (11%) were microscopically positive, and 12 (32%) were negative. Based on measurements recorded following initial laparotomy and surgical reassessment, progression during chemotherapy was noted in 40%, stage disease in 37%, and objective response in 23%. Toxicity during hyperfractionated WAI was limited and reversible. No patient beginning WAI failed to complete or required a significant treatment break. Following WAI, six patients underwent laparotomies for abdominal symptoms; five had recurrent disease. Five additional patients were managed conservatively for small bowel obstruction (SBO) or malabsorption, of whom three subsequently developed recurrence. Twenty-two patients having pelvic boosts were significantly more likely to require management for gastrointestinal morbidity (p = 0.0021). Considering all eligible patients, median disease-free and overall survivals were 18.5 and 39 months, respectively. Considering patients completing chemotherapy and WAI, median disease-free and overall survivals were 24 and 46 months, respectively.

CONCLUSIONS

(a) Disease progression occurred within three cycles of cisplatin and cyclophosphamide chemotherapy in 40% of patients with optimal (< or = 1 cm residual) Stage III ovarian carcinoma. (b) Following limited chemotherapy, hyper-fractionated WAI was acutely well tolerated. (c) Late radiation-related toxicity was observed in only three patients (8.6%) in the absence of recurrent disease. Late gastrointestinal morbidity was significantly associated with the administration of a pelvic radiotherapy (RT) boost. (d) Short duration chemotherapy followed by SRA and hyperfractionated WAI without a pelvic boost is a promising management option for patients with optimal Stage III ovarian cancer. A Phase III trial will be necessary to determine how this treatment strategy compares with chemotherapy or RT alone in this patient population.

Neurochemical and behavioral evidence that quipazine-ketanserin discrimination is mediated by serotonin2A receptor

The purposes of this study were to determine: first, if animals could be trained to discriminate a serotonin (5-HT)2 receptor agonist from a 5-HT2 receptor antagonist; second, which 5-HT2 receptor subtype was mediating the cues; and third, the usefulness of this model for studying adaptive changes in the 5-HT2 receptor system. Rats were trained to discriminate quipazine (0.5 mg/kg) from ketanserin (1.0 mg/kg) on a variable interval-20 schedule of reinforcement. After acquisition, the quipazine and ketanserin dose-response curves were found to be orderly and reproducible. Additional 5-HT2 receptor agonists (2,5-dimethoxy-4-iodoamphetamine and MK 212) and antagonists (pizotifen, mianserin, pirenperone and MDL 100,907) were tested for generalization and found to substitute for the quipazine and ketanserin cues, respectively. In antagonist studies, MDL 100,907 potently blocked quipazine discrimination. Results of ex vivo binding studies designed to estimate occupancy of 5-HT2A and 5-HT2C receptors suggested that the training dose of ketanserin blocked only 5-HT2A receptors and not 5-HT2C receptors. The combined results from the substitution, antagonism and ex vivo receptor autoradiographic studies suggest that the discriminative stimuli of quipazine and ketanserin are mediated at least in part by the 5-HT2A receptor. Additional experiments were designed to study adaptive changes in the 5-HT2A receptor. A single large dose of quipazine produced a rebound ketanserin-like effect at 20 hr after administration; however, a single large dose of ketanserin (10 mg/kg) did not produce a rebound quipazine-like effect.

Interpreting culture and psychopathology: primitivist themes in cross-cultural debate

Interpreting the cross-cultural incidence of psychopathology is a focus of continuing debate. This paper explores the lineaments of that debate and its underlying premises concerning difference and distance. Primitivism--a body of ideas, images and vocabularies about cultural others--is characteristically employed to represent non-Western peoples. But it is more fundamentally concerned with the way the West understands itself in contradistinction to these others. It is shown to be a major source of the images used to think about mental illness, and of the intellectual traditions which have constituted cross-cultural psychiatry as a comparative discipline. Psychiatric primitivism employs two opposing perspectives, which we have labelled 'Barbaric' and 'Arcadian' respectively. They are the source of contradictory assertions concerning the relationship between culture and mental illness. They provide the framework which structures contemporary research into the cross-cultural incidence and course of schizophrenia, shaping its methodology, its rhetoric, the strategies by which data are interpreted, and the conclusions which it draws. We demonstrate a convergence of themes whereby images of society, person and mental illness come to signify each other. This is epitomized in three of cross-cultural psychiatry's principal subject areas: amok, shamanism, and the therapeutic quality of 'traditional' society.

Endometrial cancer: stage at diagnosis and associated factors in black and white patients

OBJECTIVE

This study examined the relationship of clinicopathologic, health status, medical system, and socioeconomic factors to differences in stage at diagnosis of endometrial cancer in black and white patients.

STUDY DESIGN

A population-based study of 130 black and 329 white patients with invasive endometrial cancer was conducted as part of the National Cancer Institute's Black/White Cancer Survival Study. Logistic regression was used to determine the relative importance of factors thought to be related to stage at diagnosis after age and geographic location were adjusted for.

RESULTS

High-grade (poorly differentiated) lesions increased the risk for stage III or IV disease (odds ratio 8.3, 95% confidence interval 3.4 to 20.3), as did serous histologic subtype (odds ratio 3.5, 95% confidence interval 1.4 to 8.8) and no usual source of care (odds ratio 5.5, 95% confidence interval 1.4 to 20.9). In the final statistical model these three factors also accounted for the majority of the excess risk of advanced stage for blacks.

CONCLUSIONS

Black-white racial disparities in stage at diagnosis appear to be related to higher-grade lesions and more aggressive histologic subtypes occurring more frequently in black patients with endometrial cancer.

D2-specific discriminative stimuli: parameters, blocking, and rebound

This study characterizes the cue properties of quinpirole (LY 171555), a selective D2 agonist, and the blocking capabilities of spiperone, a selective D2 antagonist. After rats were trained to discriminate 0.025 mg/kg quinpirole from distilled water, a dose-response curve and time course of the quinpirole discriminative stimulus were determined. The effectiveness of three doses of spiperone in blocking the discriminative stimulus produced by 0.02 mg/kg quinpirole was then assessed. Finally, the time course of spiperone's blocking action was determined. Given the putative selective action of these drugs on D2 receptors and the parametric data presented here, it was predicted that following chronic treatment with spiperone, a rebound increase in quinpirole-appropriate responding would occur. Neither chronic treatment with spiperone nor chronic treatment with haloperidol produced the predicted changes. This result, however, may be confined to the specific dose and time parameters used.

Effect of N-0861, a selective adenosine A1 receptor antagonist, on pharmacologic stress imaging with adenosine

N6-endonorboman-2-yl-9-methyladenine (N-0861) is a drug which inhibits the A1 adenosine receptor subtype. One proposed use for N-0861 is to eliminate A1 receptor-mediated side effects such as A-V heart block and possibly angina in patients undergoing pharmacologic stress with adenosine. The goal of this study was to determine whether N-0861 has any crossover effect on the A2 vasodilatory action of adenosine or on 201TI uptake which would adversely affect imaging of coronary stenoses.

METHODS

In eight dogs with critical left anterior descending (LAD) stenoses, we compared the hemodynamic response to intravenous adenosine (250 micrograms/kg/min) before and after N-0861 administration. LAD and left circumflex (LCx) coronary flows were measured ultrasonically and regional blood flow was assessed using microspheres. Thallium-201 (18.5-37.0 MBq) was injected during adenosine hyperemia while N-0861 was present. Imaging of heart slices was performed and defect magnitude was calculated as LAD:LCx count ratios from regions of interest (ROIs) on images. Regional 201Tl activity and microsphere flow were determined by gamma well counting.

RESULTS

There was no change in mean heart rate, arterial and left atrial pressures, +dP/dt, and ultrasonically measured LAD and LCx coronary flows upon N-0861 administration. In addition, adenosine evoked a similar hemodynamic response after N-0861. There was also no change in coronary flow in the critically stenotic LAD but LCx flow tripled to 106 +/- 14 ml/min (p < 0.01).

CONCLUSION

These data indicate that N-0861 pretreatment does not adversely affect adenosine A2 receptor-mediated vasodilation and has no effect on the detection of a critical coronary stenosis by 201Tl imaging. Thus, the pretreatment strategy may prove useful for the elimination of A1 receptor-mediated side effects during pharmacologic stress imaging with adenosine.

Racial differences in tumor grade among women with endometrial cancer

Black women with endometrial cancer have more advanced disease and less favorable tumor grade than do white women. This study evaluated whether racial differences in tumor grade could be explained by hormone-related factors and other putative determinants of grade. Subjects included 207 white and 81 black postmenopausal women diagnosed with primary cancer of the uterine corpus between 1985 and 1987. Blacks had poorer tumor grade than whites (odds ratio for FIGO grade 2 versus grade 1 is 1.8; odds ratio for grade 3 versus grade 1 is 2.8). Over 75% of the excess of poorly differentiated tumors versus well-differentiated tumors among blacks could be explained by racial differences in use of replacement estrogens, age at first pregnancy, history of oophorectomy, poverty, stage of disease, use of screening, and access to health care. The most prominent factor was estrogen therapy, which was associated with favorable tumor grade and was used much less frequently by blacks. Although not statistically significant, a moderate racial difference in tumor grade remained after control of the potential explanatory explanatory variables. This may reflect true biologic variation between blacks and whites and may explain, in part, the observation that blacks with endometrial cancer have a worse prognosis.

After treatment ends: neutral time

For persons diagnosed with cancer, the remission period may be marked by increased anxiety and distress. While the medical team may view remission as an eagerly anticipated milestone, the decreased medical surveillance during this time can cause a heightened fear of recurrence for the patient. One author has called this period of remission "neutral time," a time characterized by uncertainty. The safety signal hypothesis, developed by Martin Seligman, may help to explain the anxiety experienced by some patients during the remission period. Because cancer is frequently a silent disease with no overt symptoms, patients in remission often have no safety signal to indicate that the disease will not return. A case study is presented and discussed in light of these two concepts.

Endometrial cancer risk in relation to serum lipids and lipoprotein levels

Blood lipids are useful biochemical indicators for assessing the risk of a number of chronic diseases, particularly those associated with obesity. In a multicenter case-control study that included 256 cases and 185 controls less than 75 years old, we studied the risk of endometrial cancer in relation to serum cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, and triglycerides. Contrary to expectation, blood lipids were, in general, lower among cases compared with controls. The effects of low blood lipids, specifically cholesterol and low density lipoprotein cholesterol, were limited to older women (> or = 55 years). Risk of the disease in this subgroup of 177 cases and 110 controls was increased 3-4-fold among those with the lowest cholesterol or low density lipoprotein cholesterol values. For example, after adjustment for age, education, smoking status, obesity, and body fat distribution, the relative risks of endometrial cancer across decreasing quartiles of serum cholesterol were 1.0, 2.5, 2.4, and 4.2 (P for trend < 0.01). We examined blood lipid levels by disease stage. The low lipid values of older cases did not appear to be a consequence of the disease. While we cannot rule out the possibility that hypocholesterolemia is a predisposing factor for endometrial cancer, there is no obvious biological explanation for the inverse association.

Mitochondrial DNA diversity in the pea aphid Acyrthosiphon pisum

The pea aphid Acyrthosiphon pisum has been established in North America for at least a century and occurs on a broad range of host plants. Despite its importance as a crop pest, there is little understanding of the genetic structure of its populations or the extent of genetic divergence associated with different host plant utilization. This study examined the extent of mitochondrial DNA (mtDNA) diversity among 35 clones of pea aphids from alfalfa. Polymorphisms were detected at only 2 of 126 restriction sites, suggesting the same impoverished level of genetic diversity found in prior allozyme studies. However, length variation was common and apparently arose as a result of tandem repeats in two regions of the mtDNA molecule. Region 1 occurred in proximity to the control region of the molecule, while region 2 was close to a cluster of tRNA genes flanking the NAD-dehydrogenase subunit 3 gene on the opposite side of the mtDNA molecule. Each of the aphid clones was homoplasmic for a single length variant in region 1, which varied with respect to the number of copies of a 120-bp repeat. By contrast, one-third of the clones were heteroplasmic at region 2, where they possessed a variable number of copies of a 210-bp repeat. Reanalysis of clones after 30 generations of parthenogenetic reproduction established the stability of length variants over this interval, suggesting their value in studies of the genetic structure of aphid populations.

Phase II trial of paclitaxel in patients with progressive ovarian carcinoma after platinum-based chemotherapy: a Gynecologic Oncology Group study

PURPOSE

This Gynecologic Oncology Group (GOG) trial of paclitaxel (Taxol; Bristol-Myers Squibb Co, Princeton, NJ) as salvage therapy for recurrent epithelial carcinoma of the ovary sought to confirm activity reported previously. If positive, the trial was to serve as a basis for phase III trials of Taxol in combination with platinum compounds in first-line therapy.

PATIENTS AND METHODS

Patients with recurrent, persistent, or progressive ovarian carcinoma during or after platinum-based chemotherapy received Taxol 170 mg/m2 intravenously once over 24 hours every 3 weeks. All patients had measurable disease and received premedication (dexamethasone, diphenhydramine, and ranitidine) followed by Taxol.

RESULTS

Of 49 patients, 45 were eligible and assessable. Among 43 patients who were assessable for response, there were eight complete and eight partial responses (37%). The median progression-free interval was 4.2 months, and median survival 16 months. Among 27 resistant patients who progressed during or within 6 months of prior platinum-based therapy or had stable disease as the best response, five complete (18%) and four partial (15%) responses were observed (33%). The median progression-free interval was 4 months. Among 16 sensitive patients who responded and progressed more than 6 months after prior platinum-based treatment, three complete (19%) and four partial (25%) responses were observed (44%). The median progression-free interval was 4.9 months. Grade 4 neutropenia (< 500/microL), the most frequent and severe toxicity, occurred in 73% of patients. Other hematologic effects were less frequent and less severe. Cardiac problems and hypersensitivity reactions were observed in one patient each.

CONCLUSION

Taxol is a highly active agent in ovarian carcinoma, even in patients who are clinically resistant to platinum-based chemotherapy, and produces frequent and severe, albeit manageable, myelosuppression. It is clearly active as salvage therapy for ovarian carcinoma.

A selective adenosine A1 receptor antagonist attenuates renal dysfunction during controlled hypotension with adenosine in rats

Adenosine infusion produces sustained, reversible, controlled hypotension in humans, but markedly compromises renal function. Since adenosine inhibits renal perfusion and filtration via stimulation of intrarenal A1 receptors, we hypothesized that antagonism of A1-subtype receptors with the selective adenosine A1-receptor antagonist (+-)N6-endonorbornan-2-yl-9-methyladenine (N-0861) would attenuate adenosine-induced renal dysfunction while still allowing induction and maintenance of hypotension. Systemic and renal hemodynamic and excretory responses were measured in clearance studies conducted in six groups of anesthetized rats treated with: vehicle+saline, vehicle+adenosine, N-0861 (10 or 30 mumol/kg intravenously [i.v.])+saline, or N-0861 (10 or 30 mumol/kg i.v.),+adenosine. The A1-receptor antagonist had little effect on the magnitude, maintenance, or reversibility of controlled hypotension produced by adenosine infusion. Oliguria, hypofiltration, and electrolyte retention induced by adenosine infusion were attenuated in rats pretreated with N-0861. Adenosine A1-receptor antagonism also reduced the rebound hyperfiltration and hyperperfusion associated with cessation of adenosine infusion. N-0861 alone had only a modest effect on renal or systemic hemodynamics, but produced significant dose-related diuresis/natriuresis. These results suggest that coadministration of, or pretreatment with, a selective adenosine A1-receptor antagonist may attenuate the undesirable renal effects of adenosine while allowing maintenance of controlled hypotension.

Discrimination of A1 versus A2 receptor subtype selectivity of adenosine receptor agonists in vivo

Previous attempts to discern and quantify the selectivity of agonists for A1 versus A2 adenosine receptors in vivo have been confounded by the activation of baroreceptor reflexes and/or simultaneous expression of responses to both A1 and A2 receptor activation. In anesthetized, vagotomized rats with isolated in situ constant-flow perfused hindquarters (HQ), bradycardic responses to i.v. agonist injections measured A1 receptor activation and HQ vasodilation elicited by i.a. agonist injections measured the stimulation of A2 receptors. Adenosine and 5'-N-ethylcarboxamidoadenosine (NECA) produced A2 receptor-mediated HQ vasodilation at doses 8- and 4-fold lower (-log ED50 values, 7.3 +/- 0.04 mol and 8.7 +/- 0.06 mol, respectively) than those required to evoke A1 receptor-mediated bradycardia (-log ED50 values, 6.4 +/- 0.01 mol and 8.1 +/- 0.07 mol, respectively). N6-cyclopentyladenosine (CPA) was approximately 8-fold selective for A1 receptors (-log ED50 values, A1, 8.5 +/- 0.05 mol; A2, 7.6 +/- 0.16 mol). 2-(Phenylamino)adenosine (CV-1808) and 2[2(4-fluorophenyl)ethoxy]adenosine (FPEA) were at least 125- and 200-fold more potent agonists at A2 receptors (-log ED50 values, 7.7 +/- 0.10 mol and 8.0 +/- 0.24 mol, respectively) than at A1 receptors (-log ED50 values, 5.6 +/- 0.08 mol and 5.7 +/- 0.01 mol, respectively). These studies demonstrated that stimulation of A1 and A2 receptors may be discriminated in vivo and that such responses are selective, reproducible, dose-dependent and quantifiable.(ABSTRACT TRUNCATED AT 250 WORDS)

Phase II trial of menogaril in patients with squamous carcinoma of the cervix: a Gynecologic Oncology Group study

A phase II trial of 200 mg/m2 menogaril was conducted by the Gynecologic Oncology Group (GOG) in women with advanced or recurrent squamous carcinoma of the cervix who had received no previous chemotherapy. Twenty-three patients were placed on the study; 22 are evaluable for toxicity and for response. One patient had incomplete data and was inevaluable. Nine patients (40.9%) had previously undergone surgery, and 21 (95.5%) had received radiotherapy before this trial. GOG grade 3 granulocytopenia occurred in 1 patient (4.5%) but none developed grade 3 or 4 thrombocytopenia. One patient (4.5%) had grade 3 gastrointestinal toxicity. Neither complete nor partial responses were observed in this trial, although 9 patients (40.9%) had stable disease lasting 2 months or more. Menogaril at this dose and schedule is inactive in advanced or recurrent squamous carcinoma of the cervix.

Hot and cold in transformation: is Iban medicine humoral?

Iban categories of hot and cold are examined in the context of humoral medical systems in southeast Asia. These categories are more than binary and oppositional: they are also contradictory and can only be understood in terms of their capacity for transformation in 'depth'. Analysis of the Iban epistemology of temperature sensation reveals the limitations of reductionist empirical approaches to hot and cold. Illness is apprehended, at one level, in terms of unusual conjunctions of opposite temperatures which signify a deeper disturbance in the relationship between body and soul, humans and spirits. Iban therapy redefines and relocates these categories in their proper place and at their appropriate level. It progresses from hot lay treatments to cool ritual treatments, yet cannot be accounted for within a limited framework of homeostatic balance. This paper develops an ethnographically grounded definition of humoralism which emphasizes non-reductive logic, cultural practice and transformation. The key element, transformation, is defined as a transition between categories and a shift in the level of interpretation which fundamentally alter the Iban experience of body and illness.

Drug discrimination is a continuous rather than a quantal process following training on a VI-TO schedule of reinforcement

Debate continues as to whether drug discrimination in animals is an inherently quantal or continuous process. This issue is important in determining the appropriate interpretation of results from drug discrimination studies designed to assess the nature of drug-induced interoceptive cues. The quantal approach holds that subjects perceive a drug cue in an all-or-none manner, while the continuous view proposes that when appropriate training and testing procedures are used, subjects can discriminate along a continuum of interoceptive cues. Data consistent with the quantal view have consistently been generated by animals trained to respond on schedules of reinforcement having an FR component. Since quantal responding is a characteristic of these schedules, results from drug discrimination studies using training schedules with FR components are of little value in empirically determining whether drug discrimination reflects a quantal or continuous process. Use of variable schedules of reinforcement might be more appropriate because the pattern of responding generated does not preclude results consistent with either of the competing views. Data from the following studies that trained subjects using VI schedules with a concurrent TO for incorrect lever responding were analyzed: Barrett et al. (1982): L-5-hydroxytryptophan versus saline; Smith (1990): diazepam versus pentylenetetrazol; Barrett et al. (1992): amphetamine versus haloperidol; Barrett and Steranka (1983): amphetamine versus haloperidol. In every case, when experimental conditions produced a group mean intermediate to that for the training drugs, the distribution of scores for individual animals was normally rather than bimodally distributed.

Circadian-timed combination doxorubicin-cisplatin chemotherapy for advanced endometrial carcinoma. A phase II study of the Gynecologic Oncology Group

Patients with advanced or recurrent endometrial cancer of any cell type having measurable disease have been entered into this study to determine the effectiveness and toxicity of circadian-timed doxorubicin-cisplatin chemotherapy. This Phase II study involved no randomization with treatment initiated with doxorubicin 60 mg/m2 over 30 minutes at 6:00 a.m., followed by cisplatin 60 mg/m2 over 30 minutes at 6:00 p.m. every 28 days. Treatment was continued for eight cycles or to a maximum tolerable doxorubicin dose of 480 mg/m2 for patients without progression. Thereafter, responders continued on cisplatin alone. A review of 30 evaluable patients showed 6 (20%) complete responses, 12 (40%) partial responses, and 7 (23%) with stable disease. The number of treatment courses ranged from 2 to 14 with a median of 6.5. the median white blood cell nadir for the 27 patients experiencing leukopenia was 1,600/mm3 (range: 300-3,600/mm3) For the 16 patients experiencing thrombocytopenia the median nadir was 48,500/mm3 (range: 8,000-138,000/mm3). There were no treatment-related deaths. Circadian-timed delivery of doxorubicin-cisplatin chemotherapy was reasonably well tolerated and demonstrated notable response rates in patients with advanced or recurrent endometrial carcinoma.

A phase II trial of tricyclic nucleoside phosphate in patients with advanced squamous cell carcinoma of the cervix. A Gynecologic Oncology Group Study

A Phase II trial of TCN-P was conducted in metastatic or recurrent squamous cell carcinoma of the cervix using a 5-day continuous infusion schedule. The starting dose was 35 mg/m2 x 5 days and courses were repeated every 6 weeks. Among 21 evaluable patients, 2 responses were observed. One patient had a complete response for 19+ months. Another patient had a partial response for 5+ months, but developed symptomatic hypocalcemia, requiring discontinuation of the drug. Using this dose and schedule TCN-P appears to have limited activity in metastatic or recurrent squamous cell cancer of the cervix.

Use of ultrasonography and secondary wound closure to facilitate diagnosis and treatment of a cranial mediastinal abscess in a dog

A 3-year-old dog was examined because of acute, severe respiratory distress. Harsh inspiratory sounds, oral abrasions, and pyrexia were identified. On thoracic and cervical radiographs, the trachea appeared to be ventrally displaced and narrowed for several centimeters of its length at the thoracic inlet. Cytologic examination of a transcutaneous aspirate from the caudal cervical region revealed a neutrophilic exudate with extracellular bacteria. The ultrasonographic appearance of the thoracic inlet lent support to a diagnosis of cranial mediastinal abscess. Drainage and debridement of the abscess was accomplished via a ventral midline cervical approach, and the site was managed as an open wound. After 6 days, secondary wound closure was performed. The ventral cervical approach prevented contamination of the pleural space, and treatment as an open wound allowed inspection of the affected tissues to determine optimal time for wound closure. The cause of this cranial mediastinal abscess was unknown.

Interactions of adenosine A1 receptor-mediated renal vasoconstriction with endogenous nitric oxide and ANG II

Renal vasoconstrictor responses to the adenosine A1 agonist N6-cyclopentyladenosine (CPA) were compared in the in situ autoperfused rat kidney to responses evoked by angiotensin II (ANG II), endothelin-1 (ET-1), arginine vasopressin (AVP), carbocyclic thromboxane A2 (CTxA2), phenylephrine (PE), and 5-hydroxytryptamine (5-HT). On the basis of their ED50 values (dose of agonist, in mass units, that produced 50% of maximal response to that agonist), the order of vasoconstrictor potency was ANG II > or = AVP > ET-1 > CPA > 5-HT > or = PE > CTxA2. Dose-response curves to CPA were shallower and maximal responses were weaker than those produced by the other agonists. Maximal responses, the log ED50, and the slope of the dose-response curve to CPA were markedly potentiated in the presence of the nitric oxide (NO) synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME). Selective antagonism of A1 receptors increased renal blood flow and markedly attenuated CPA-induced renal vasoconstriction in the absence or presence of L-NAME but had no effect on the maximal responses to ANG II. Conversely, AT1 receptor antagonism attenuated renal vasoconstriction produced by ANG II but had little effect on the produced by CPA. These results suggest that endogenous NO modulates renal vasoconstriction produced by A1 receptor stimulation and provide evidence against an interaction between renovascular adenosine A1 and angiotensin AT1 receptors.

Moderate alcohol consumption and the risk of endometrial cancer

In a multicenter case-control study that included 400 cases and 297 controls, we examined the relation of moderate alcohol consumption to risk of endometrial cancer. We estimated average weekly intake of alcohol during adulthood from the reported frequency of intake of beer, wine, and liquor. The relative risk of endometrial cancer was 0.82 (95% confidence interval = 0.6-1.2) among women who drank, compared with lifelong abstainers. The weak protective effect of alcohol was due to a stronger inverse association among young women (< 55 years). In young women, the age-adjusted relative risks for three levels of drinking ( < 1, 1-4, > 4 drinks per week), from lowest to highest, were 0.78, 0.64, and 0.41 compared with nondrinkers. The risk estimates were not materially altered after adjustment for a variety of factors related to alcohol intake and to low risk of the disease (for example, smoking, oral contraceptive use, low body mass index, increased physical activity). The protective effect of alcohol could not be attributed to one particular type of alcohol-containing beverage, but beer appeared to have the most pronounced effect. These results suggest an inverse association between moderate alcohol consumption and endometrial cancer risk among young women, but support for a causal association is qualified and requires confirmation.