Past and present physical activity and endometrial cancer risk

We examined the relation between physical activity and endometrial cancer using data from a multicentre case-control study involving 405 endometrial cancer cases and 297 population controls. Estimates of recreational (i.e. active sport, walks and hikes) and nonrecreational activity (i.e. house cleaning, climbing stairs and walking or standing on the job) were obtained using interview information. After adjustment for age, study area, education, parity, years of use of oral contraceptives, years of use of menopausal oestrogens and cigarette smoking, recent recreational inactivity was associated with increased risk (RR = 1.9 for lowest vs highest tertile). Similarly, recent nonrecreational inactivity was associated with increased risk (RR = 2.2 for lowest vs highest tertile). Further adjustment for body mass and nonrecreational activity attenuated the association between risk and recent recreational inactivity (RR = 1.2; 95% CL = 0.7-2.0) but adjustment for body mass and recreational activity did not alter the association between risk and recent nonrecreational inactivity (RR = 2.0; 95% CL = 1.2-3.1). To evaluate the relation between risk and sustained inactivity, we simultaneously examined activity levels at three periods (RR i.e. age 20-29, age 30-39 and recently) in women age 50 and older. After adjustment for potential confounders and body mass, risk was elevated among women who were always recreationally inactive (RR = 1.5 for always active vs always inactive) and among women who were always nonrecreationally inactive (RR = 1.6 for always active vs always inactive). This study suggests that physically inactive women may be at increased risk of endometrial cancer because they are more likely to be overweight or obese. Our data also suggest that inactivity per se may be associated with an increased risk of endometrial cancer. However, we cannot rule out the possibility that our results, particularly those for nonrecreational activity, reflect unmeasured confounding factors. Future studies should attempt to obtain more detailed assessments of physical activity, including the intensity with which an individual engaged in an activity and the actual time involved in exertion.

Relation of endometrial cancer risk to past and contemporary body size and body fat distribution

In a multicenter case-control study that included 403 cases and 297 controls, we examined the relation of past and contemporary body size, including body fat distribution, to the risk of endometrial cancer. The relative contributions of past and contemporary body size were assessed by examining weight and height histories provided by the subjects. Anthropometric indicators thought to reflect early environmental influences (e.g., height and sitting height), current weight, and fat distribution patterns were measured directly. Height was not a risk factor for endometrial cancer, but inexplicably, sitting height was inversely associated with risk. Weight during early adulthood appeared to be directly related to disease risk, but the association was explained by contemporary weight and thus weight gain during adulthood. While contemporary weight was associated with risk of endometrial cancer, the effect was restricted to those in the top quartile. Women whose measured weight at interview exceeded 78 kg had 2.3 times the risk of those weighing less than 58 kg (95% confidence interval, 1.4 to 3.7). Upper-body obesity (waist-to-thigh circumference ratio) was a risk factor independent of body weight. After adjustment for weight, the relative risks of endometrial cancer across increasing quartiles of upper-body obesity were 1.0, 1.5, 1.8, and 2.6 (P for trend < 0.001). These data indicate that both obesity and the distribution of adipose tissue accumulated during adult life increase endometrial cancer risk substantially.

Oral contraceptives and endometrial cancer: do other risk factors modify the association?

The joint effect of use of combination-type oral contraceptives and other exposure factors on risk of endometrial cancer was examined in data from a multicenter case-control study conducted in 5 areas of the United States. Cases were 405 women with histologically confirmed invasive epithelial endometrial cancer first treated at one of 7 participating hospitals. A total of 297 population-based controls of similar age, race, and geographic area were selected as a comparison group. Information on exposure factors was derived from in-person interviews. Combination-type oral contraceptive (COC) use was associated with a significant reduction in risk of endometrial cancer, with an adjusted odds ratio (OR) of 0.4 (95% confidence interval 0.3 to 0.7) for ever compared to never use. Long-term (> or = 10 years) users experienced a markedly lower risk (OR = 0.2). Women who discontinued COC use > or = 20 years earlier remained at reduced risk (OR = 0.7) compared with non-users. The negative association with COC use was apparent regardless of the presence or level of several other risk factors for endometrial cancer, including age, menopausal status, parity, obesity, ever-use of menopausal estrogens, smoking history, or history of infertility. The magnitude of the negative association observed in COC users, however, was considerably diminished in women with no full-term births and in women who subsequently used replacement estrogens for 3 or more years. These results provide new evidence that the protective effect of COC use lasts for 20 or more years after use is discontinued, and highlight several sub-groups of users in whom the level of protection is attenuated by the presence of other risk factors for this disease.

Dietary associations in a case-control study of endometrial cancer

Despite the established role of obesity in the etiology of endometrial cancer, limited data are available from analytical epidemiologic studies on the association of risk with dietary factors. A case-control study of 399 cases and 296 controls conducted in five areas of the United States from 1 June 1987 to 15 May 1990, enabled evaluation of risk related to dietary intakes adjusted for potential confounders. Caloric intake was associated modestly with increased risk (odds ratio [OR] = 1.5, 95 percent confidence interval [CI] = 0.9-2.5 for highest cf lowest quartiles of intake), with the principal contributors being fat and protein calories. After adjustment for other risk factors, including body mass, increased risk was associated with higher intakes of fat. Several components of fat investigated were associated with increased risk, although associations were slightly stronger for saturated fat (OR = 2.1, CI = 1.2-3.7) and oleic acid (OR = 2.2, CI = 1.2-4.0) than for linoleic acid (OR = 1.6, CI = 0.9-2.8). Food-group analyses showed intake of complex carbohydrates--and specifically of breads and cereals--associated with reduced risks (OR = 0.6, CI = 0.4-1.1), whereas animal fat and fried foods were associated with elevated risks (OR = 1.5 and 1.7, respectively). The relations of endometrial cancer with animal fat and complex carbohydrates were independent. No consistent associations were noted for intakes of cholesterol, fiber, vitamins A and C, individual carotenoids, or folate-rich foods. These data imply an etiologic role for a diet rich in total fat and/or animal fat and low in complex carbohydrates with endometrial cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Topical sucralfate in the treatment of vaginal ulceration

BACKGROUND

Non-neoplastic vaginal ulceration is at times recalcitrant to traditional methods of treatment. Sucralfate, a basic aluminum salt of sucrose octasulfate, binds preferentially to ulcerated areas and promotes healing, an effect that does not appear to be acid-dependent.

CASE

Three cases of vaginal ulceration were treated with vaginal douches of sucralfate 10% suspension twice daily. One of the cases was due to laser ablation for intraepithelial neoplasia, one was of uncertain etiology, and one was caused by pessary use.

CONCLUSION

After failure of the initial therapeutic regimens, sucralfate treatment was successful in all three cases and was well tolerated without side effects. Sucralfate vaginal douches should be considered for the treatment of non-neoplastic vaginal ulcerations, particularly when other therapy has failed.

Randomized comparison of the antiemetic efficacy of a serotonin type 3 receptor antagonist (MDL 72,222) with a high-dose metoclopramide regimen

This pilot randomized study compared MDL 72,222, a highly selective 5-HT3 receptor antagonist, with a high-dose metoclopramide regimen (HDM) for chemotherapy-induced nausea and vomiting. MDL 72,222 was given in 20 mg intravenous doses 30 minutes before chemotherapy, as well as 2, 6, and 12 hours after chemotherapy infusion. The HDM was composed of diphenhydramine 50 mg i.v., metoclopramide 2 mg/kg i.v., and lorazepam 0.04 mg/kg i.v. administered 30 minutes before chemotherapy and 2, 4, 6, and 8 hours after chemotherapy. Patients were randomized to either MDL 72,222 (n = 12) or the HDM (n = 12) and were matched for age, weight, Karnofsky performance status, and chemotherapy. More patients in the MDL 72,222 group had received prior cisplatin. The MDL 72,222 group and the HDM group received a mean cisplatin dose of 66 mg/m2 and 62 mg/m2, respectively. Patients were observed for retching and/or emesis for 24 hours and completed a visual analog scale (VAS) for nausea. Six MDL 72,222 and five HDM patients had no vomiting. One MDL 72,222 and two HDM patients had one episode of emesis within 24 hours of chemotherapy. The median number of emetic episodes in the first 24 hours was 0.5 for MDL 72,222 and 1.0 for HDM patients. HDM patients were frequently asleep and were not awakened for evaluation of nausea with the VAS; 58% (70 of 120) of the HDM (mean score: 19.1 mm) and 14% (17 of 119) of the MDL 72,222 (mean score: 17.1) patients could not have VAS scores obtained (X2 = 50.74, p < 0.001). MDL 72,222 had similar efficacy with less sedation, and further trials are warranted.

In vitro and in vivo pharmacological characterization of N6-cyclopentyl-9-methyladenine (N-0840): a selective, orally active A1 adenosine receptor antagonist

The pharmacological and biochemical profile of N6-cyclopentyl-9-methyladenine (N-0840) was elucidated in vitro and in vivo. In radioligand binding assays, N-0840 had 14- to 400-fold greater affinity for A1 than A2 adenosine receptors and did not inhibit radioligand binding to alpha-1, alpha-2, beta, 5-hydroxytryptamine 1a, muscarinic, D1 or D2 receptors at concentrations < or = 10,000 nM. In guinea pig tissues, N-0840 competitively antagonized A1 receptor-mediated, 5'-N-ethylcarboxamidoadenosine-induced negative inotropism (paced left atria, KB = 0.83 microM), chronotropism (spontaneously beating right atria, KB = 0.91 microM) and dromotropism (Langendorff heart; KB = 0.72 microM). However, at concentrations up to 100 microM, N-0840 did not antagonize A2 adenosine receptor-mediated, 5'-N-ethylcarboxamidoadenosine-induced relaxations of the guinea pig aorta. N-0840 was a poor inhibitor of total cyclic nucleotide phosphodiesterase activity and of adenosine uptake (IC50 > 200 microM), and it did not inhibit adenosine deaminase activity. In anesthetized rats, N-0840 selectively antagonized A1 adenosine receptor-mediated bradycardia, but generally failed to affect A2 adenosine receptor-mediated vasodilation in the in situ perfused hindquarters (A2/A1 selectivity: > or = 33-fold). The duration of action of N-0840 ranged from 1 min (after 3 mumol/kg i.v.) to 8 hr (after 100 mumol/kg p.o.). N-0840 (< or = 100 mumol/kg i.v.; < or = 1,000 mumol/kg p.o.) had little or no effect on blood pressure or heart rate and produced no adverse drug reactions.(ABSTRACT TRUNCATED AT 250 WORDS)

Cigarette smoking and the risk of endometrial cancer

A case-control study involving 405 cases of epithelial endometrial carcinoma (newly diagnosed between 1987 and 1990 in five US areas) and 297 population controls enabled evaluation of risk in relation to detailed smoking characteristics. Cigarette smokers were at a reduced risk of disease, with the effect primarily restricted to women whose diseases were detected postmenopausally (relative risk (RR) = 0.6, 95% confidence interval 0.4-0.9). Among postmenopausal women, current smokers showed the greatest reduction in risk (RR = 0.4, 95% confidence interval 0.2-0.7), with former smokers, including those who had recently stopped, being less affected (RR = 0.8). Other measures of smoking were highly correlated with currency of smoking, but there were no clear patterns of risk with either duration or intensity of smoking. Smoking appeared to reduce risk to the greatest extent in subjects who were multiparous, obese, or nonusers of exogenous hormones, but none of these relations was statistically significant. The results support the notion that smoking reduces the risk of endometrial cancer through extraovarian endogenous hormonal mechanisms, but further studies are needed to clarify why reduced risks are most pronounced among postmenopausal women and those currently exposed to cigarette smoke.

Selective pelvic and periaortic lymphadenectomy does not increase morbidity in surgical staging of endometrial carcinoma

OBJECTIVE

The objective of this study was to retrospectively assess whether there was increased morbidity associated with the addition of selective pelvic and periaortic lymphadenectomy to hysterectomy in patients with endometrial carcinoma.

STUDY DESIGN

From 1977 through 1988, 196 patients undergoing selective pelvic and periaortic lymphadenectomy plus hysterectomy were compared with 104 patients who underwent hysterectomy alone for endometrial adenocarcinoma.

RESULTS

Only after adjusting for covariates was selective pelvic and periaortic lymphadenectomy associated with a higher estimated blood loss, which increased linearly with weight and was higher for black than for white women. The transfusion rate was similar for the two groups (selective pelvic and periaortic lymphadenectomy 6%, hysterectomy 10%). The mean blood loss was significantly different among the four gynecologic oncology surgeons (range 343 to 652 ml). The operating time primarily depended on patient weight and race, surgeon, and estimated blood loss. Postoperative hospital stay increased significantly with age, surgeon, wound infections, thrombotic events, and serious complications. Selective pelvic and periaortic lymphadenectomy had no effect on wound infections, which were directly related to operating time. Seventy-five (38%) of the selective pelvic and periaortic lymphadenectomy group and 19 (18%) of the hysterectomy group (p < 0.01) received whole-pelvic radiation with no difference in bowel complications (selective pelvic and periaortic lymphadenectomy 2/75, hysterectomy 1/19). The risk of serious complications was associated only with increasing age.

CONCLUSION

Selective pelvic and periaortic lymphadenectomy in patients with endometrial carcinoma does not significantly add to morbidity from hysterectomy, which is related primarily to other factors such as patient weight, age, and race; operating time; and surgeon.

Reproductive, menstrual, and medical risk factors for endometrial cancer: results from a case-control study

OBJECTIVE

Our objective was to evaluate the risk for endometrial cancer in relation to reproductive, menstrual, and medical factors.

STUDY DESIGN

A case-control study of 405 endometrial cancer cases and 297 population controls in five areas of the United States enabled risk to be evaluated.

RESULTS

A major risk factor was the absence of a prior pregnancy (relative risk 2.8, 95% confidence interval 1.7 to 4.6). The protective effect of pregnancy appeared to reflect the influence of term births, because spontaneous and induced abortions were unrelated to risk. Among nulliparous women infertility was a significant risk factor, with women having sought medical advice having nearly eight times the risk of those without difficulty conceiving. After adjustment for other reproductive characteristics, age at first birth and duration of breast-feeding were not related to risk.

CONCLUSIONS

Elevated risks were found for subjects reporting early ages at menarche (relative risk 2.4 for ages < 12 vs > or = 15) and longer days of flow (relative risk 1.9 for > or = 7 vs < 4 days), but there was no relationship with late ages at natural menopause. Height was not associated with risk, but there was a significant relation to weight, with the risk for 200 versus < 125 pounds being 7.2 (95% confidence interval 3.9 to 13.3). After adjustment for weight and other factors, histories of hypertension and gallbladder disease were not significantly related to risk, but an effect of diabetes persisted (relative risk 2.0, 95% confidence interval 1.1 to 3.6). Hirsutism developing at older ages was also significantly related (relative risk 2.0, 95% confidence interval 1.2 to 3.4).

Use of a retained urethral catheter in three dogs with prostatic neoplasia

Percutaneous nephrostomy catheters modified by cutting off the tubing connectors were implanted in three dogs with prostatic neoplasia to relieve or prevent stranguria. One catheter was implanted with a guide wire through a perineal urethrotomy, and two catheters were implanted via celiotomy and cystotomy. Morbidity and complications were minimal. Inflammation of the abdominal incision was present from day 4 to day 8 in the dogs with celiotomy. Urinary incontinence was continuous in one dog and intermittent in two dogs. Hematuria occurred in two dogs. The retained urethral catheter was a suitable palliative treatment for urethral obstruction in three dogs with prostatic neoplasia.

N-0861 selectively antagonizes adenosine A1 receptors in vivo

Experiments were performed to determine the antagonistic actions of (+/-)N6-endonorbornan-2-yl-9-methyladenine (N-0861) at A1 and A2 adenosine receptors in vivo, and to evaluate the pharmacodynamics of the observed responses. The selectivity of antagonism of A1 vs. A2 receptors by N-0861 was evaluated by generating dose-response curves to adenosine-induced bradycardia (A1 effect), and vasodilation in the in situ constant-flow perfused rat hindquarter vasculature (A2 effect). N-0861, at doses greater than or equal to 1 mumol/kg + 0.04 mumol/kg per min, i.v. produced dose-related rightward shifts of the A1 dose-response curve, but had no effect on the A2 dose-response curve at doses as high as 100 mumol/kg, i.v. In contrast, the non-selective A1/A2 adenosine receptor antagonist 8-phenyltheophylline antagonized both A1 and A2 receptor-mediated responses to adenosine. The minimum effective i.v. dose and the duration of action of N-0861 were determined by evoking bradycardic responses to i.v. adenosine (A1 effect) in anesthetized, vagotomized, beta-blocked rats before and after single bolus doses of vehicle or N-0861 (0.3, 0.6, 1.0, 3.0 or 10.0 mumol/kg). The lowest i.v. dose of N-0861 to antagonize A1 receptor-mediated bradycardia was 0.3 mumol/kg i.v.; the duration of effect ranged from 1 min (following 0.3-1 mumol/kg) to approximately 2.5 h (following 10 mumol/kg). N-0861 is a selective (by greater than or equal to 333-fold) antagonist of adenosine A1 receptors.

A phase II trial of leuprolide acetate in patients with advanced epithelial ovarian carcinoma. A Gynecologic Oncology Group study

Twenty-five evaluable patients with advanced or recurrent epithelial ovarian carcinoma that was no longer controllable with surgery, radiation therapy, and/or chemotherapy were treated with leuprolide acetate, a gonadotropin-releasing hormone agonist, 1 mg subcutaneously daily. One partial response (4%) was observed among the 25 patients. The upper 95% confidence bound of the response rate is 17.6%. Fifteen patients (60%) exhibited stable disease for at least 8 weeks, and 9 patients (36%) developed progressive cancer while receiving treatment. The regimen was well tolerated with no patient experiencing life-threatening toxicity. Mild toxicities included leukopenia in 2 patients (8%), thrombocytopenia in 2 patients (8%), gastrointestinal toxicity in 5 patients (20%), anemia in 4 patients (16%), hot flashes in 1 patient (4%), and facial swelling in 1 patient (4%). Thus, leuprolide acetate was well tolerated but has insignificant activity in treating patients with chemotherapy-refractory ovarian adenocarcinoma.

Phase II trial of ifosfamide and mesna in leiomyosarcoma of the uterus: a Gynecologic Oncology Group study

OBJECTIVE

The purpose of this study was to evaluate the activity of ifosfamide (isophosphamide) in patients with advanced or recurrent leiomyosarcoma not previously exposed to chemotherapy.

STUDY DESIGN

This is a phase II groupwide study of the Gynecologic Oncology Group. Thirty-five patients were treated with ifosfamide 1.5 gm/m2 daily intravenously for 5 days with mesna (mercaptoethane sodium sulfonate). Fifty-six patients had received prior abdominal hysterectomy and 15 prior radiotherapy. The dose was reduced to 1.2 gm/m2 daily in patients who had received prior radiotherapy.

RESULTS

Gynecologic Oncology Group grade III or IV granulocytopenia occurred in 4 (11%) patients, and none had grade IV thrombocytopenia. One (2.8%) patient had grade IV neurotoxicity. Partial responses were observed in 6 of 35 (17.2%) patients. The 95% confidence interval for response was 6.6% to 33.7%.

CONCLUSION

These results indicate that ifosfamide has modest activity in patients with advanced or recurrent leiomyosarcomas of the uterus.

Tolerance, withdrawal, and supersensitivity to dopamine mediated cues in a drug-drug discrimination

Rats were trained to discriminate between 0.25 mg/kg amphetamine (AMPH) and 0.03 mg/kg haloperidol (HAL) in a two-lever drug discrimination task. In order to test for a drug-induced withdrawal state, animals were assigned to one of three chronic treatment groups and given injections of AMPH, HAL, or distilled water (DW) for 10 consecutive days. Subjects from each treatment condition were then tested at 24, 48, or 72 h after the final injection. At the 24 h retest interval, subjects injected with AMPH responded as though administered an acute dose of HAL (0.028 mg/kg) and subjects injected with chronic HAL responded as though administered an acute dose of AMPH (0.15 mg/kg). By 72 h choice behavior had returned to pretreatment values. To determine whether the rebound observed after 10 days of drug treatment was present after a single injection, independent groups of subjects were injected with single doses of either 10 mg/kg AMPH or 1.0 mg/kg HAL and then retested from 4 h to 48 h later. Single doses of both AMPH and HAL produced significant rebounds that peaked between 20 h (AMPH) and 24 h (HAL) following administration. In a third experiment, animals were tested with or without acute doses of drug following pretreatment with either HAL or AMPH. Receptor supersensitivity accounts for the tolerance observed to HAL 24 h after treatment with 1.0 mg/kg HAL, whereas receptor subsensitivity accounts for the tolerance observed 20 h after treatment with 10 mg/kg AMPH.

Carbonic anhydrase inhibitors are antiarthritic in the rat

Adjuvant-induced arthritis in rats was attenuated by the therapeutic administration of carbonic anhydrase inhibitors. Female Lewis rats with established disease were treated daily (day 18 through day 50) with various carbonic anhydrase inhibitors; oedema and joint integrity (X-ray) were determined post-treatment. Acetazolamide, ethoxzolamide, methazolamide, and dichlorphenamide reduced paw oedema and attenuated the deterioration of the joints of rats with adjuvant arthritis. However, no carbonic anhydrase inhibitor tested possessed significant, acute, anti-inflammatory activity in the carrageenan-paw oedema test. The activity of carbonic anhydrase inhibitors in the chronic model of inflammation may be due to their reported inhibition of bone resorption.

Synthesis, calcium-channel-blocking activity, and antihypertensive activity of 4-(diarylmethyl)-1-[3-(aryloxy)propyl]piperidines and structurally related compounds

A series of 4-(diarylmethyl)-1-[3-(aryloxy)propyl]piperidines and structurally related compounds were synthesized as calcium-channel blockers and antihypertensive agents. Compounds were evaluated for calcium-channel-blocking activity by determining their ability to antagonize calcium-induced contractions of isolated rabbit aortic strips. The most potent compounds were those with fluoro substituents in the 3- and/or 4-positions of both rings of the diphenylmethyl group. Bis(4-fluorophenyl)acetonitrile analogue 79 was similar in potency to bis(4-fluorophenyl)methyl compound 1. The methylene analogue of 1 (78) and derivatives of 1 that contained a hydroxyl (76), carbamoyl (80), amino (81), or acetamido (82) substituent on the methyl group were less potent. In most cases, substituents on the phenoxy ring, changes in the distance between the aryloxy group and the piperidine nitrogen, and the substitution of S, N(CH3), or CH2 for the oxygen atom of the aryloxy group had only a small to moderate effect on the potency. The best compounds in this series were more potent than verapamil, diltiazem, flunarizine, and lidoflazine, but were less potent than nifedipine. Compounds were evaluated for antihypertensive activity in spontaneously hypertensive rats (SHR) at an oral dose of 30 mg/kg. Of the 55 compounds tested, only nine produced a statistically significant (p less than 0.05) reduction in blood pressure greater than 20%; all of these compounds had fluoro substituents in both rings of the diphenylmethyl group. One of the most active compounds in the SHR at 30 mg/kg was 1-[4-[3-[4-[bis(3,4-difluorophenyl)methyl]-1- piperidinyl]propoxy]-3-methoxyphenyl]ethanone (63), which produced a 35% reduction in blood pressure and was similar in activity to nifedipine. At lower doses, however, 4-[bis(4-fluorophenyl)methyl]-1-[3-(4-chlorophenoxy)propyl]piperidine (93) was one of the most effective antihypertensive agents, producing reductions in blood pressure of 17 and 11% at oral doses of 10 and 3 mg/kg, respectively; 63 was inactive at 10 mg/kg.

Combined interferon alfa and doxorubicin in the treatment of advanced cervical cancer

Interferon alfa and doxorubicin have been shown to have synergistic effects when tested in vitro with cells derived from cervical cancers. A clinical trial was designed, testing interferon alfa plus doxorubicin in patients with advanced or recurrent cervical cancers. Twenty-one patients were given interferon alfa, 10 million units per square meter intramuscularly and 10 million units per square meter intravenously over a 30-minute infusion period. One hour later 20 mg/m2 doxorubicin was given intravenously slowly over a 2-hour period. Treatments were repeated once weekly for 3 weeks. Initial response evaluation was done at week 5, and treatment was continued on an every-other-week schedule for patients showing favorable responses or stable disease. Bone marrow, hepatic, and renal toxicities were minimal. Fever and malaise were the major sources of toxicity. Of the 17 evaluable patients, six had clinical partial responses. Two of the responders have enjoyed more than 5 years' survival. This regimen is well tolerated and does have efficacy in some patients with advanced cervical cancers.

AHR-16303B, a novel antagonist of 5-HT2 receptors and voltage-sensitive calcium channels

In vivo and in vitro methods were used to characterize AHR-16303B, a novel compound with antagonistic action at 5-HT2 receptors and voltage-sensitive calcium channels. The 5-HT2 receptor-antagonistic properties of AHR-16303B were demonstrated by inhibition of (a) [3H]ketanserin binding to rat cerebral cortical membranes (IC50 = 165 nM); (b) 5-hydroxytryptamine (5-HT)-induced foot edema in rats (minimum effective dose, (MED) = 0.32 mg/kg orally, p.o.); (c) 5-HT-induced vasopressor responses in spontaneously hypertensive rats (SHR) (ID50 = 0.18 mg/kg intravenously (i.v.), 1.8 mg/kg p.o.), (d) 5-HT-induced antidiuresis in rats (MED = 1 mg/kg p.o.), and (e) platelet aggregation induced by 5-HT + ADP (IC50 = 1.5 mM). The calcium antagonist properties of AHR-16303B were demonstrated by inhibition of (a) [3H]nimodipine binding to voltage-sensitive calcium channels on rabbit skeletal muscle membranes (IC50 = 15 nM), (b) KCl-stimulated calcium flux into cultured PC12 cells (IC50 = 81 nM), and (c) CaCl2-induced contractions of rabbit thoracic aortic strips (pA2 = 8.84). AHR-16303B had little or no effect on binding of radioligands to dopamine2 (DA2) alpha 1, alpha 2, H1, 5-HT1 alpha, beta 2, muscarinic M1, or sigma opioid receptors; had no effect on 5-HT3 receptor-mediated vagal bradycardia; and had only minor negative inotropic, chronotropic, and dromotropic effects on isolated guinea pig atria. In conscious SHR, 30 mg/kg p.o. AHR-16303B completely prevented the vasopressor responses to i.v. 5-HT, and decreased blood pressure (BP) by 24% 3 h after dosing.

Cardiovascular and renal actions of AHR-16303B, an antagonist of 5-HT2 receptors and calcium channels, in hypertensive and normotensive rats

The cardiovascular and renal responses to AHR-16303B, a novel antagonist of 5-hydroxytryptamine (5-HT2) receptors and calcium channels, were examined in spontaneously hypertensive (SHR) and normotensive rats (NTR) and compared with verapamil and ritanserin. In SHR, AHR-16303B (10-300 mg/kg orally, p.o.) produced dose-related reductions in mean arterial blood pressure (MABP), accompanied by modest isokaliuretic diuresis and unchanged heart rate (HR). In NTR, 10-30 mg/kg p.o. AHR-16303B had no effect on MABP or renal excretory function; 100 and 300 mg/kg reduced MABP but had only transient effects on HR; 100 mg/kg produced antidiuresis in NTR. Both strains of rats tolerated doses of AHR-16303B as high as 300 mg/kg. In both SHR and NTR, verapamil (10-100 mg/kg p.o.) produced dose-related reductions in MABP, antinatriuresis at 60 and 100 mg/kg, and variable effects on HR. Oral ritanserin had no effect on MABP of SHR or NTR at 3 or 10 mg/kg. AHR-16303B is unique in that it simultaneously antagonizes 5-HT2 receptors and produces safe and effective reduction of elevated BP without altering HR or triggering renal compensatory antidiuresis. At effective 5-HT2/calcium antagonistic doses, AHR-16303B has no effect on cardiorenal homeostasis in normotensive animals.

Rebound cue state following a single dose of haloperidol

It has been reported that chronic administration of haloperidol produces an amphetamine-like rebound cue state. The experiments reported here were designed to assess whether a similar rebound phenomenon would result from a single dose of haloperidol. Rats were trained to discriminate .5 mg/kg amphetamine from distilled water. Five groups were formed to allow testing of haloperidol's effect at 12, 18, 24, 30, and 36 hr postinjection. Each animal was given 0, .5, 1.0, and 1.5 mg/kg haloperidol at its appropriate injection time in a counterbalanced fashion with one week between each test. A shift in the dose-response function of amphetamine that occurred during these weeks, however, precluded appropriate analysis of haloperidol's effects. Given this result, a second experiment was conducted using a between-subjects design. Half of the animals were injected with 1 mg/kg haloperidol 23 hr prior to testing, whereas the others were injected with distilled water. When tested, the haloperidol group responded 33% of the time on the amphetamine-correct lever, whereas the control group responded at 20%. The observation of posthaloperidol rebound in the between-subjects study and the failure to find significant temporal patterns of rebound phenomena using a within-subjects design have both theoretical and methodological importance.

Adaptation of brain 5HT2 receptors after mianserin treatment: receptor sensitivity, not receptor binding, more accurately correlates with behavior

This study investigates the possibility that mianserin, a serotonin-2 (5HT2) receptor antagonist, produces a prolonged antagonism of quipazine discrimination, consistent with its prolonged biochemical effects. Rats were trained on a saline-quipazine (1.5 mg/kg) discrimination; following acquisition, the animals were assigned to groups and given injections of 2.0 mg/kg mianserin. Individual groups were tested at 45 min and successive 12-hr intervals for their ability to discriminate 0.75 mg/kg of quipazine, a dose that elicited 75% responding on the quipazine lever. Blockade of the quipazine cue persisted for 48 hr following mianserin administration. The above procedure was replicated using lower doses of mianserin (0.25, 0.10 and 0.05 mg/kg) and two other 5HT2 antagonists, pizotifen and metergoline (2.0 mg/kg), both of which showed similar profiles of extended antagonism. Changes in both receptor density and receptor sensitivity were investigated as possible mechanisms of mianserin's prolonged activity. Analysis of [3H]ketanserin binding revealed that a single 2.0-mg/kg dose of mianserin produced a significant decrease in the number of receptor sites (44%) 24 hr after treatment; however, this loss of sites recovered by 36 hr post-injection and could therefore not account for mianserin's continued antagonism at this and later times. 5HT-mediated phosphoinositide hydrolysis in cerebral cortex slices was used as a measure of 5HT2 receptor sensitivity. Treatment of rats with 2 mg/kg of mianserin caused a marked reduction in the maximum phosphoinositide response to 5HT that persisted for up to 36 hr. Hence, the time course for recovery of 5HT2 receptor sensitivity corresponded more closely to behavioral recovery than did 5HT2 receptor binding.

Tuboovarian pregnancy associated with elevated maternal serum alpha-fetoprotein. A case report

Tuboovarian implantation is a rare form of pregnancy that is difficult to diagnose in early gestation. A patient with a tuboovarian pregnancy presented with abnormally elevated initial screening maternal serum alpha-fetoprotein (MSAFP). The elevated MSAFP and a pelvic mass of uncertain etiology on ultrasonography delayed the diagnosis until laparotomy was performed. Elevated MSAFP accompanied by oligohydramnios and a pelvic mass is a particularly suspect finding for a tuboovarian or other type of extrauterine implantation.