Use of the rat model to study hCG/LH effects on uterine blood flow

Luteinizing hormone (LH) and human chorionic gonadotropin (hCG) share a common receptor. LH/hCG receptors, located in the vascular smooth muscle and endothelial cells of uterine blood vessels, are most numerous in smaller intramyometrial vessels and are cyclic in nature. There is a correlation between hCG levels and decreased uterine vascular resistance in humans, and in pseudopregnant rats, hCG decreases uterine blood flow. We found that systemic administration of hCG to cycling rats reduced uterine blood flow within 20 minutes on all days of the estrous cycle when flow was measured via the radioactive microsphere method. This effect was absent in ovariectomized rats. To determine the response to hCG at the microvascular level, we measured uterine arteriolar diameters in vivo via videomicroscopy after direct application or injection of hCG in rats on diestrus-1, diestrus-2, and proestrus. When hCG was suffused over the uterus (20 IU/60 mL), the uterine arterioles in diestrus (1 and 2) rats dilated but in proestrus rats were constricted. Neither response was altered in animals whose ovaries were removed 3 hours previously. An intraperitoneal injection of hCG (50 IU) caused uterine arteriolar constriction in diestrus-2 and proestrus animals but no change in diestrus-1. In ovariectomized rats, uterine arteriolar constriction following hCG injection was absent. Thus, the response of the uterine vasculature is not only cycle day dependent but also dependent on the route of administration. The effect of hCG on uterine blood flow in the rat may be a direct action of hCG, or it could be secondary to the release of other vasoactive substances known to be released by hCG. hCG might also alter blood flow by inducing angiogenesis.

An overview of the past, present, and future of nongonadal LH/hCG actions in reproductive biology and medicine

Even though there were hints, it was not until 1986 that a number of laboratories worldwide began to demonstrate unequivocally the presence and functions of luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptors in various female and male nongonadal tissues. There was no species specificity but there was tissue specificity in the nongonadal LH/hCG receptor distribution. Nongonadal receptor levels were lower but they were regulated and processed and used signaling mechanisms similarly to gonadal receptors. Although still greater understanding is needed, gains made in the last decade demonstrate that nongonadal actions of LH/hCG are physiologically important and may have relevance to better understanding several diseases and their treatment. A recently developed LH receptor knockout model has begun to reaffirm and extend the importance of nongonadal LH signaling in the body.

A proposed role for hCG in clinical obstetrics

The role of human chorionic gonadatropin (hCG) in the maintenance of early pregnancy is well known. Recent data suggests that hCG may play a role in the maintenance of the later stages of pregnancy as well, by directly and indirectly promoting uterine quiescence. If hCG acts as an endogenous tocolytic in normal pregnancy, then it may be an ideal candidate for therapy of preterm labor as well. We present compelling in vitro as well as in vivo data, which support the role of hCG in the maintenance of normal uterine quiescence. Additionally, we will present in vivo and in vitro data that confirms the ability of hCG to directly promote relaxation of uterine contractions. This review provides a basis for future study of the use of hCG in clinical obstetrics. Given the limited effectiveness of tocolytic therapies available at the time, hCG may provide a promising pharmacological approach to the pervasive problem of preterm labor in human pregnancy. While further work is needed, initial data strongly support this novel use of hCG in clinical obstetrics.

Role of gastric antioxidant and anti-Helicobactor pylori activities in antiulcerogenic activity of plantain banana (Musa sapientum var. paradisiaca)

Studies with plantain banana (Musa sapientum var. paradisiaca) have indicated its ulcer protective and healing activities through its predominant effect on various mucosal defensive factors [Sanyal et.al, Arch Int Pharmacodyn, 149 (1964) 393; 155 (1965) 244]. Oxidative stress and Helicobactorpylori colonization are considered to be important factors in the pathogenesis of gastric ulcers. In the present study methanolic extract of plantain banana pulp (BE) was evaluated for its (i) antiulcer and antioxidant activities in 2 hr cold restraint stress and (ii) anti-H.pylori activity in vitro. The extract (BE, 50 mg/kg, twice daily for 5 days) showed significant antiulcer effect and antioxidant activity in gastric mucosal homogenates, where it reversed the increase in ulcer index, lipid peroxidation and super oxide dismutase values induced by stress. However it did not produce any change in catalase values, which was significantly decreased by stress. Further, in the in vitro study. BE (0.32-1,000 microg/ml) did not show any anti-H.pylori activity. The results suggest absence of anti-H. pyloric activity of methanolic extract of banana in vitro and its antioxidant activity may be involved in its ulcerprotective activity.

The presence of functional luteinizing hormone/chorionic gonadotropin receptors in human sperm

The functional receptors that bind human CG (hCG) and LH have recently been identified in a number of nongonadal human tissues. The current experiments tested the hypothesis that human ejaculated sperm may also contain them. The data revealed that they, indeed, do as determined by the presence of receptor messenger RNA and receptor protein that can bind (125)I-hCG. The receptors were functional, as indicated by an increase in cyclic AMP levels and activation of sperm protein kinase A following treatment with hCG or LH. Treatment with these hormones, on the other hand, had no effect on sperm protein kinase C activity. Now that the functional LH/hCG receptors are found in human sperm, it is important to determine whether hCG treatment could improve the outcome of infertility procedures.

Chemoprevention of colon cancer by a glutathione conjugate of 1,4-phenylenebis(methylene)selenocyanate, a novel organoselenium compound with low toxicity

We have consistently shown that several synthetic Organoselenium compounds are superior cancer chemopreventive agents and less toxic than selenite or certain naturally occurring selenoamino acids. 1,4-Phenylenebis(methylene)selenocyanate (p-XSC) is the lead Organoselenium compound in that it has been shown to be the most effective and the least toxic agent in several experimental cancer models. It is not known whether p-XSC or one of its metabolites is responsible for its chemopreventive efficacy. As an initial step, we synthesized one of its putative metabolites, i.e., the glutathione conjugate of p-XSC (p-XSe-SG), and determined its stability in the pH range from 2 to 8 and in the diet under normal feeding conditions. We also assessed its maximum tolerated dose and examined its chemopreventive efficacy against azoxymethane (AOM)-induced colon carcinogenesis in male F344 rats. p-XSe-SG proved to be very stable over the pH range tested. The maximum tolerated dose of p-XSe-SG determined in a 6-week subchronic toxicity study was found to be >210 ppm (>40 ppm selenium) when the compound was added to AIN-76A high-fat diet. To assess the efficacy of this agent in the postinitiation period of colon carcinogenesis, male F344 rats 6 weeks of age were fed the high-fat diet, and at beginning of weeks 7 and 8, all of the rats intended for carcinogen treatment were given AOM at a dose of 15 mg/kg body weight by s.c. injection. Two days after the carcinogen treatment, the groups of rats consuming the high-fat control diet began their respective high-fat experimental diet regimens with 0, 56, or 84 ppm p-XSe-SG (0.1, 10, and 15 ppm of selenium) supplementation. All animals continued on their respective diets for 38 weeks after the AOM-treatment and were then killed. Colon tumors were evaluated histologically using routine procedures and were also analyzed for cyclooxygenase (COX)-1 and COX-2 expression and enzymatic activities. The results indicate that p-XSeSG administered during the post-initiation stage significantly inhibited both the incidence (P < 0.05-0.01) and the multiplicity (P < 0.05-0.005) of AOM-induced colon adenocarcinomas. This agent also greatly suppressed the multiplicity (P < 0.01-0.001) of AOM-induced exophytic adenocarcinomas in a dose-dependent manner. Feeding of 56 or 84 ppm p-XSe-SG in the diet significantly suppressed total COX activity (P < 0.02 to -0.01) and COX-2 specific activity (P < 0.005-0.0005) but had minimal effect on the protein expression levels of COX-1 and COX-2. These results suggest that the newly developed synthetic Organoselenium compound, p-XSe-SG, is stable in the diet and at wide pH ranges, inhibits colon carcinogenesis when administered during the postinitiation stage, and inhibits COX activity. Compared with previous efficacy studies and considering the toxicity associated with selenium, p-XSe-SG seems to be the least toxic Organoselenium chemopreventive agent thus far tested in the experimental colon carcinogenesis. Studies are in progress to delineate whether p-XSe-SG is also effective when administered during the progression stage of colon carcinogenesis.

Absent coronary venous sinus: a rare anomaly

A 42-year-old man, presenting with dyspnea on exertion and ST segment depression on treadmill test, was found to have absent coronary venous sinus on coronary angiography. We report this case of isolated congenital absence of coronary venous sinus because of its rarity.

Effect of Convolvulus pluricaulis Chois on gastric ulceration and secretion in rats

Convolvulus pluricaulis is an indigenous plant commonly mentioned in Ayurveda, an ancient system of Indian medicine, as a rasayana which is mainly advocated for use in rejuvenation therapy. The present study was conducted to evaluate the potential anti-ulcerogenic effect of juice of fresh whole plants of C. pluricaulis (CPJ) against various experimental gastric ulcer models induced by ethanol, aspirin, 2 hr cold restraint stress and 4 hr pyloric ligation in rats. The drug was given orally twice daily for five days in the doses of 375 and 750 mg/kg body weight. CPJ showed anti-ulcerogenic effect at both doses in all the experimental gastric ulcer models and was comparable to the reference drug sucralfate (250 mg/kg). Gastric juice secretion and mucosal studies were undertaken to find out the possible mechanism of action of antiulcer effect by studying its effects both on offensive and defensive mucosal factors. The antiulcerogenic effect of CPJ was found to be due to augmentation of mucosal defensive factors like mucin secretion, lifespan of mucosal cells and glycoprotiens rather than on the offensive factors like acid-pepsin.

Total synthesis of heliannone A and (R,S)-heliannone B, two bioactive flavonoids from Helianthus annuus cultivars

The total synthesis of heliannone A (1) and (R,S)-heliannone B (2), two bioactive flavonoids originally isolated from Helianthus annuus cultivars, is described.

Modulation of experimental colon tumorigenesis by types and amounts of dietary fatty acids

Epidemiological studies and laboratory animal model assays suggest that a high intake of dietary fat promotes colorectal cancer. Several in vivo and in vitro studies support the hypothesis that omega-6 fatty acids promote colon tumorigenesis, whereas omega-3 fatty acids lack promoting activity. Fat intake in the United States traditionally includes high amounts (30% of total caloric intake) of saturated fat rather than omega-6 fatty acids. Therefore, the present study was designed to compare the modulatory effects of a high-fat diet containing mixed lipids (HFML), a diet rich in saturated fatty acids (the average American diet), a diet with fish oil (HFFO) that is rich in omega-3 fatty acids, and a low-fat corn oil diet (LFCO) on the formation of chemically induced colonic aberrant crypt foci (ACF) and tumors, cyclooxygenase (COX)-2 activity, and apoptosis during experimental colon carcinogenesis. At 5 weeks of age, groups of male F344 rats were fed a 5% corn oil diet (LFCO). At 7 weeks of age, rats intended for carcinogen treatment received s.c. injections of azoxymethane at a dose level of 15 mg/kg of body weight once weekly for 2 weeks. Beginning 1 day after the carcinogen treatment, groups of rats were then maintained on experimental diets containing 20% HFML or 20% HFFO. Rats were killed at 8, 23, or 38 weeks after azoxymethane treatment. Colonic ACF and tumors were evaluated histopathologically, and apoptosis was evaluated by the terminal deoxynucleotidyl transferase-mediated nick end labeling method. Colonic mucosae and tumor samples harvested at week 38 were analyzed for COX-2 synthetic activity and expression. The rats fed the HFML diet showed significantly increased total colonic ACF (P < 0.001-0.0001) with a multiplicity of > or = 4 aberrant crypts/focus (P < 0.0001) compared with the effects of the HFFO or LFCO diets at week 8, 23, and 38. Interestingly, there was a 2- to 3-fold increase (> or = 4) in multicrypt foci in rats given the HFML diet as compared with such foci in rats fed the HFFO or LFCO diets. By week 23, the HFML diet had significantly increased the incidence of colonic tumors (30-60%) and their multiplicity (100-141%) when compared with the effects of the LFCO or HFFO diets. At week 38, the HFML diet had induced 100% colon tumor incidence and a 4-fold multiplicity of adenocarcinomas compared with the LFCO and HFFO diets. At weeks 23 and 38, a significantly lower percentage of apoptotic colonic epithelial cells were observed in the tumors of animals fed the HFML diet as compared with those fed the HFFO diet. The HFML diet caused significantly increased levels of COX-2 activity in colon tumors (P < 0.05-0.01), and these tumors had enhanced levels of COX-2 expression as compared with those in assays with LFCO or HFFO diets. These observations demonstrate for the first time that HFML diets containing high levels of saturated fatty acids (such as those in Western diets) promote colon carcinogenesis. Although the mechanisms involved in colon tumor promotion by a HFML diet are not fully known, our results indicate that the modulation of eicosanoid production via the influence on COX activity and the suppression of apoptosis may play a key role in HFML diet-induced colon tumorigenesis.

Effect of Centella asiatica Linn on physical and chemical factors induced gastric ulceration and secretion in rats

Centella asiatica is commonly mentioned as a Rasayana in Ayurveda, an ancient system of Indian medicine for various ailments including abdominal disorders. Rasayanas have been advocated for use in rejuvenation therapy. The present study was conducted to evaluate the possible anti-ulcerogenic activity of fresh juice of C. asiatica (CAJ) against ethanol-, aspirin-, cold-restraint stress- and pyloric ligation induced gastric ulcers in rats. The drug given orally in doses of 200 and 600 mg/kg twice daily for five days, showed significant protection against all the above experimental ulcer models and the results were comparable with those elicited by sucralfate (SF, 250 mg/kg, p.o., BD x 5 days). CAJ showed little or no effect on offensive acid-pepsin secretion. However, at 600 mg/kg CAJ significantly increased gastric juice mucin secretion and increased the mucosal cell glycoproteins signifying increase in cellular mucus. It also decreased cell shedding indicating fortification of mucosal barrier. Thus, the ulcer protective effect of CAJ may be due to strengthening of the mucosal defensive factors.

A subtoxic interactive toxicity study of ethanol and chromium in male Wistar rats

The purpose of this study was to evaluate the interactive toxicity of ethanol with potassium dichromate (K2Cr2O7-chromium). Young, male Wistar rats (100-120 g) were divided into four groups of five or six animals each and were dosed, through water, with 10% ethanol (vol./vol.) or 25 ppm chromium or were dosed with a combination of ethanol+chromium at the same concentrations for a period of 22 weeks ad libitum and were maintained on normal diet. Control animals were maintained on a normal diet and water for the same period. The serum succinate dehydrogenase and liver total triglyceride levels were significantly reduced in the three treated groups. The serum alkaline phosphatase levels were significantly reduced in ethanol-treated rats, and there was no significant change in the acid phosphatase activity. Serum aspartate and alanine aminotransferase levels in the three treated groups were significantly increased. The liver glycogen significantly decreased in both the ethanol-treated and the chromium-treated rats. There was a significant increase in liver total cholesterol levels in chromium-treated rats. Total glutathione levels were significantly decreased in the livers of ethanol-treated and ethanol+chromium-treated rats. To further substantiate these findings, a histological examination of the liver and kidneys was undertaken. The livers of alcohol-treated animals showed altered hepatic architecture in the centrilobular and periportal areas, with increased sinusoidal space (space of Disse), vacuolation, and necrosis of hepatocytes. Similar changes were observed in a histological examination of the livers of chromium-treated rats, except that the damage to the hepatocytes was more confined to the periportal area. Moreover, histological examination of the livers of ethanol+chromium-treated rats revealed uniform damage in the centrilobular and periportal areas, as was observed in the groups treated either with ethanol or chromium. The histological examination of the kidneys in the three treated groups revealed significant damage to the renal tubules and Bowman's capsule, which showed vacuolation and degeneration of the basement membrane. These findings correlate well with the serum enzyme levels found in the treated groups. It is evident from this study that chronic ethanol consumption sensitizes the liver to the toxic action of agents such as chromium. It leads to impairment of the biochemical functions in the liver, and it causes liver and kidney damage. Long-term simultaneous exposure to ethanol and chromium may cause severe health problems in people who are alcoholics and work in chrome-plating and leather-tanning industries.

Modulation of inducible nitric oxide synthase expression in rat intestinal cells by colon tumor promoters

Metabolic epidemiological studies in humans and laboratory animal models demonstrate that consumption of diets high in fat and low in fiber excrete increased levels of 1,2-diacyl-sn-glycerol (DAG) and secondary bile acids such as deoxycholic acid (DA) and lithocholic acid that have been shown to promote colon carcinogenesis. The secondary bile acids and DAG have been shown to activate protein kinase C (PKC) and induce colonic cell proliferation. A large body of evidence indicates that iNOS, an inducible isoform of nitric oxide synthase, is over-expressed in human colon adenomas and in chemically-induced colon tumors of laboratory animals. However, the precise cascade of intracellular events that leads to the iNOS over-expression remains to be fully explored. In this study, we investigated the relationship between induction of iNOS and activation of the PKC pathway by DAG and DC, in an in vitro system using the rat intestinal cell line, RIE-1. As an initial step, we determined whether lipopolysaccharide (LPS) and phorbol 12-myristate 13-acetate (PMA) modulate iNOS protein expression in RIE-1 cells. Treatment of RIE-1 cells with LPS and PMA for 4 h significantly elevated the iNOS protein expression. The induction of iNOS by the treatment with LPS/PMA was concentration- and time-dependent. Treatment with LPS/DAG or LPS/DC also caused iNOS over-expression in a concentration- and time-dependent fashion suggesting that DAG and DC induce iNOS activity in intestinal cells. Pretreatment with specific PKC inhibitors, bisindolylmaleimide I or Gö 6976, inhibited LPS/PMA, LPS/DAG, or LPS/DC-induced iNOS expression and activity. Extracts of the cells treated with LPS/PMA, LPS/DAG or LPS/DC had a high iNOS activity compared to that of control (p<0.04 to p<0.0001). Taken together, our data suggest a possible role of colon tumor promoters, DAG and DC, for iNOS over-expression through activation of the PKC pathway.

A new naphthoquinone from Bombax malabaricum

A new naphthoquinone 1 together with 7-hydroxycadalene (2) and 8-formyl-7-hydroxy-5-isopropyl-2-methoxy-3-methyl-1,4-naphthoquinone (3) were isolated from the heartwood of Bombax malabaricum. The new naphthoquinone was characterized as 7-hydroxy-5-isopropyl-2-methoxy-3-methyl-1,4-naphthoquinone (1) based on spectral and chemical studies.

Targeted disruption of luteinizing hormone/human chorionic gonadotropin receptor gene

LH/hCG receptors were disrupted by gene targeting in embryonic stem cells. The disruption resulted in infertility in both sexes. The gonads contained no receptor mRNA or receptor protein. Serum LH levels were greatly elevated, and FSH levels were moderately elevated in both sexes; estradiol and progesterone levels decreased but were not totally suppressed in females; testosterone levels were dramatically decreased and estradiol levels moderately elevated in males. The external and internal genitalia were grossly underdeveloped in both sexes. Abnormalities included ambiguous vaginal opening, abdominal testes, micropenis, dramatically decreased weights of the gonads and reproductive tract, arrested follicular growth beyond antral stage, disarray of seminiferous tubules, diminished number and hypotrophy of Leydig cells, and spermatogenic arrest beyond the round spermatid stage. LH/hCG receptor gene disruption had no effect on FSH receptor mRNA levels in ovaries and testes, progesterone receptor (PR) levels in ovaries and androgen receptor (AR) levels in testes. However, it caused a dramatic decrease in StAR and estrogen receptor-alpha (ERalpha) mRNA levels and an increase in ERbeta mRNA levels in both ovaries and testes. Estradiol and progesterone replacement therapy in females and testosterone replacement in males, to determine whether phenotype and biochemical changes were a consequence of decreased gonadal steroid levels or due to a loss of LH signaling, revealed complete restoration of some and partial restoration of others. Nevertheless, the animals remained infertile. It is anticipated that the LH receptor knockout animals will increase our current understanding of gonadal and nongonadal actions of LH and hCG.

Chemoprevention of colonic aberrant crypt foci in Fischer rats by sulforaphane and phenethyl isothiocyanate

Epidemiological studies have linked consumption of broccoli to a reduced risk of colon cancer in individuals with the glutathione S-transferase M1 (GSTM1) null genotype. GSTs are involved in excretion and elimination of isothiocyanates (ITCs), which are major constituents of broccoli and other cruciferous vegetables and have cancer chemopreventive potential, so it is speculated that ITCs may play a role in protection against human colon cancer. However, there is a lack of data from animal studies to support this. We carried out a bioassay to examine whether sulforaphane (SFN) and phenethyl isothiocyanate (PEITC), major ITCs in broccoli and watercress, respectively, and their corresponding N:-acetylcysteine (NAC) conjugates, show any chemopreventive activity towards azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) in F344 rats. Groups of six male F344 rats were treated with AOM subcutaneously (15 mg/kg body wt) once weekly for 2 weeks. SFN and PEITC and their NAC conjugates were administered by gavage either three times weekly for 8 weeks (5 and 20 micromol, respectively) after AOM dosing (post-initiation stage) or once daily for 3 days (20 and 50 micromol, respectively) before AOM treatment (initiation stage). The bioassay was terminated on week 10 after the second AOM dosing and ACF were quantified. SFN, SFN-NAC, PEITC and PEITC-NAC all significantly reduced the formation of total ACF from 153 to 100-116 (P < 0.01) and multicrypt foci from 52 to 27-38 (more than four crypts/focus; P < 0.05) during the post-initiation treatment. However, only SFN and PEITC were effective during the initiation phase, reducing the total ACF from 153 to 109-115 (P < 0.01) and multicrypt foci from 52 to 35 (more than four crypts/focus; P < 0.05). The NAC conjugates were inactive as anti-initiators against AOM-induced ACF. These findings provide important laboratory evidence for a potential role of SFN and PEITC in the protection against colon cancer.

Does full-term pregnancy at a young age protect women against breast cancer through hCG?

Recent studies found that human and animal breast tissues and human breast cell lines contain low levels of receptors that bind hCG and its structural and functional homologue, LH. Those gonadotropins exert numerous anticancer effects in breast cancer models and cells, which might explain decreased breast cancer incidence in women who complete full-term pregnancies at a young age. The new findings also imply that premature chronic elevations of LH levels might contribute to decreased breast cancer incidence in women with early menopause, and elevated LH levels might contribute to a better prognosis after ovariectomy. Those findings predict that breast cancer risk might be reduced by early hCG treatment of women who plan to delay their first pregnancies; prophylactic hCG treatment might help women with family histories of breast cancer or oncogene mutations that predict breast cancer; and better prognoses might result when hCG is administered to breast cancer tissue.

Effect of Piper longum Linn, Zingiber officianalis Linn and Ferula species on gastric ulceration and secretion in rats

Use of Dipaniya Mahakasaya, a group consisting of 10 herbal drugs, has been suggested in Charaka Samhita to improve digestion. Out of these 10 plants, three, viz. P. longum (water decoction), Z. officianalis (water decoction) and Ferula species (colloidal solution) were studied for their antiulcer and mechanism of antiulcer effects in rats. All the drugs in the dose of 50 mg/kg, p.o., 60 min prior to experiment, showed significant protection against gastric ulcers induced by 2 hr cold restraint stress, aspirin (200 mg/kg, 4 hr) and 4 hr pylorus ligation. The antiulcerogenic effect seemed to be due to the augmentation of mucin secretion and decreased cell shedding rather than offensive acid and pepsin secretion which however, were found to be increased by them.

Experimental evaluation of Bocopa monniera on rat gastric ulceration and secretion

The anti-ulcerogenic effect of fresh juice from the whole plant of Bocapa monniera Wettst. (BMJ) commonly known as Brahmi in Hindi was examined using gastric ulcer models induced by ethanol, aspirin, 2 h cold restraint stress and 4 h pylorus ligation. Bocapa monniera juice (BMJ) at doses of 100 and 300 mg/kg and sucralfate at a dose of 250 mg/kg were given orally, twice daily for 5 days. BMJ 100-300 mg/kg produced significant antiulcer activity in all the experimental gastric ulcer models except in case of ethanol-induced ulcers where 100 mg/kg was not found to decrease it significantly. BMJ (100-300 mg/kg) was found to have little or no effect on the offensive acid-pepsin secretion, while cell shedding (microgram DNA/mg of protein) and mucin secretion in terms of total carbohydrates:protein ration (TC:P), the two important parameters of defensive factors were significantly decreased and increased respectively indicating enhancement of protective mucosal factors. Both BMJ (300 mg/kg) and SF showed tendency to increase the mucosal glycoproteins in terms of TC:P, though individual carbohydrates and total carbohydrates were either increased or showed a tendency to increase. Thus, ulcer protective effect of BMJ may be due to its effect on mucosal defensive factors like enhanced mucin secretion, mucosal glycoprotein and decreased cell shedding rather than on offensive factors such as acid and pepsin.

Preventive potential of wheat bran fractions against experimental colon carcinogenesis: implications for human colon cancer prevention

Epidemiological studies suggest an inverse relationship between the intake of dietary fiber, particularly fiber from cereal grains, and colon cancer risk. Animal model assays have demonstrated that the protective effects of dietary fiber on colon cancer development depend on the nature and source of the fiber. Wheat bran (WB) appears to inhibit colon tumorigenesis more consistently than do oat bran or corn bran. This study was designed to determine whether specific WB fractions such as WB fiber, WB lipids, or phytic acid differentially affect colon carcinogenesis in a well-established colon cancer model. In addition, the modulating effect of specific fractions of WB on the activities of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-1 and COX-2 enzymes were assessed in colon tumors as those have been shown to play a role in tumor progression. At 5 weeks of age, groups of male F344 rats were assigned to one of six diets: a high-fat diet containing 10% WB (control diet) and experimental high-fat diets containing 10% dephytinized WB (WB-P), 10% defatted WB (WB-F), 10% dephytinized and defatted WB (WB-PF), 10% WB-PF fortified with 2% bran oil and/or with 0.4% phytate. At 7 weeks of age, all eats except those in the vehicle-treated groups were given two weekly s.c. injections of azoxymethane (AOM) at a dose rate of 15 mg/kg body weight/week. They continued to receive their respective diets until 50 weeks after carcinogen treatment and were then killed. Colon tumors were analyzed for iNOS, COX-1, and COX-2 expression and enzymatic activities. Colon tumors were evaluated histopathologically and classified as adenomas and adenocarcinomas. We found that removal of phytic acid (WB-P) or lipids (WB-F) from WB had no significant effect on colon tumor incidence (% animals with tumors) or multiplicity (tumors/ animal), whereas removal of both phytate and lipids from WB (WB-PF) significantly increased colon tumor multiplicity and volume. Interestingly, WB-PF fortified with excess bran oil or with bran oil plus phytate significantly inhibited colon tumor incidence, multiplicity, and volume; but supplementation of WB-PF with phytate alone had no significant effect on colon tumorigenesis in rats suggesting that lipid fraction of WB possesses tumor-inhibitory properties. Moreover, feeding WB-PF diet significantly increased iNOS, total COX and COX-2 enzyme activities, and iNOS protein expression in colon tumors as compared with wheat bran control diet. Feeding the WB-PF that was fortified with excess bran oil alone or with bran oil plus phytate significantly suppressed the activities of iNOS and COX-2 as well as the expression of iNOS and COX-2 in colon tumors compared with that in rats fed the WB diet or WB-PF diet. The study demonstrates for the first time that the lipid fraction of wheat bran has strong colon tumor inhibitor properties. The exact mechanism(s) by which the lipid fraction of WB inhibits colon carcinogenesis in addition to alteration of iNOS and COX activities remains to be elucidated. Additional studies are warranted to identify biologically active constituents of lipid fraction of WB and their relative role in colon tumor inhibition.

Potential regulation of GnRH gene by a steroidogenic factor-1-like protein

Steroidogenic factor-1 (SF-1) is a member of an orphan nuclear hormone receptor superfamily. It plays a critical role in the development and function of the hypothalamic-pituitary-gonadal and adrenal axis. However, whether SF-1 can regulate transcription of gonadotrophin-releasing hormone (GnRH) gene is not known. To examine this possibility, we first over-expressed SF-1 and found that it not only decreased steady state GnRH messenger ribonucleic acid (mRNA) levels but also reduced its promoter activity in GT1-7 neurons. The inhibitory effect of SF-1 was lost when the 5'-flanking region of GnRH gene containing two distal (-1479 to -1474 bp and -1059 to -1054 bp) hexamers was deleted. Gel mobility shift assays showed that GT1-7 cell nuclear extracts contained a protein that formed a specific complex with synthetic oligonucleotides containing the two distal hexamers or a consensus SF-1 binding sequence. The migration of this complex was, however, slower than the complex formed with MA-10 cell nuclear extracts which were shown to contain a 53 kDa SF-1 protein. The addition of anti-SF-1 antibody supershifted the complex formed with MA-10, but not with GT1-7 cell nuclear extracts. The same antibody, however, detected a 60 kDa protein and immunostained nuclei of GT1-7 neurons. These results are consistent with GT1-7 neurons containing an SF-1-like protein that can bind to the distal hexamer sequences in the 5'-flanking region of rat GnRH gene to inhibit its transcription.

Luteinizing hormone receptor expression in leiomyomatosis peritonealis disseminata

BACKGROUND

Leiomyomatosis peritonealis disseminata has been attributed to estrogen stimulation and is seen only rarely in postmenopausal women. In such cases, pathogenesis is uncertain.

CASE

Leiomyomatosis peritonealis disseminata tumors were resected from a postmenopausal woman. She was receiving tamoxifen therapy for breast cancer and had bilateral ovarian Brenner tumors. Estrogen and progesterone receptors were detected. Immunohistochemical analysis indicated that LH receptors were present.

CONCLUSION

Luteinizing hormone receptors were identified in leiomyomatosis peritonealis disseminata in one woman. Levels of FSH and LH increase after menopause, and immunohistochemical analysis showed the presence of LH receptors, so gonadotropin rather than estrogen stimulation might have contributed to development of leiomyomatosis peritonealis disseminata in this uncommon case.

Simultaneous administration of diethylphthalate and ethyl alcohol and its toxicity in male Sprague-Dawley rats

Phthalate esters have been implicated as xenoestrogens. One among them is di-ethylphthalate (DEP), which is used as plasticizer, detergent base, and binder in incense sticks and after-shave lotions. DEP is one of the contaminants of freshwater and marine ecosystems. Incense stick workers are occupationally exposed to DEP and some workers are chronic alcoholics. Therefore, a study was undertaken to evaluate the interactive toxicity of DEP with ethyl alcohol (EtOH) in young male Sprague-Dawley rats. The rats were given 50 ppm DEP (w/v), 5% EtOH (v/v) and a combined dose of 50 ppm DEP (w/v)+EtOH (5% v/v) in water ad libitum for a period of 120 days and were maintained on normal diet. Control animals received normal diet and plain water. During the treatment rats were weighed every week and water consumption per day was measured. After the completion of treatment, liver weight/body weight, liver weight, body weight, serum enzymes and other biochemical parameters were assessed. It was found that there was no significant change observed in body weight, liver weight, liver weight/body weight and water consumption. It was observed that there was a significant decrease in liver aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in EtOH, DEP and EtOH+DEP treated rats in the order of EtOH>DEP>EtOH+DEP as compared with control. Serum AST, ALT, acid phosphatase (ACP), alkaline phosphatase (ALP), succinate dehydrogenase (SDH) and liver ACP showed significant increase in DEP and EtOH+DEP treated rats in the order of DEP>EtOH+DEP as compared with control and EtOH treated rats. On the contrary, there was no significant change in liver ALP levels in treated rats. There was significant increase in liver SDH, glycogen, total triglyceride, total cholesterol and lipid peroxidation in DEP and EtOH+DEP treated rats, but no significant changes in the serum SDH, glucose and total triglyceride levels. Serum total cholesterol levels in DEP and EtOH+DEP treated rats were significantly high as compared to control and EtOH treated rats. These results show that there is no interaction of DEP with EtOH but DEP alone leads to severe impairment of lipid metabolism coupled with toxic injury to the liver as evident from significantly altered lipid and enzyme levels in the liver and serum. Long term simultaneous exposure to DEP and EtOH may have severe implications for humans who are occupationally exposed to these two xenobiotics.

Colon cancer: a role for cyclo-oxygenase-2-specific nonsteroidal anti-inflammatory drugs

Large bowel cancer is not only the third most frequent cancer in the world but is one of the most common human malignancies in Western countries, including North America. In recent years, multidisciplinary research in epidemiology, molecular biology, and laboratory animal model studies have contributed much to our understanding of the aetiology of this cancer; more importantly, it has enabled us to devise preventive strategies. Several epidemiological studies have detected a 40 to 50% decrease in risk of colorectal cancer in individuals who regularly use aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs). Clinical trials with NSAIDs in patients with familial adenomatous polyposis have demonstrated that treatment with NSAIDs caused regression of pre-existing adenomas. Preclinical efficacy studies have provided scientifically sound evidence as to how NSAIDs act to retard, block, or reverse colonic carcinogenesis. Equally exciting are opportunities for effective chemoprevention with selective cyclo-oxygenase-2 inhibitors in a variety of animal models of colon cancer. Selective cyclo-oxygenase-2 inhibitors such as celecoxib have been proven to be effective chemopreventive agents against colonic carcinogenesis with minimal gastrointestinal toxicity. Our exploration of the multistep process of carcinogenesis has provided substantial insights into the mechanisms by which anti-inflammatory agents modulate these events. There is growing optimism for the view that realisation of preventive concepts in large bowel cancer will also serve as a model for preventing malignancies of the prostate and breast.

Effect of mild irritant on gastric mucosal offensive and defensive factors

The effect of hypotonic medium (Distilled water: DW) and hypertonic saline (HS: 5% NaCl) compared to control normal saline (NS) was studied on gastric ulcer induced by aspirin, 6 h cold restraint stress, ethanol, and pylorus ligation in rats. DW did not afford any protection while HS showed significant ulcer protective effects in all gastric ulcer models studied. The cytoprotective effect of HS seemed to be not only due to its effect on gastric acid secretion but also its effect on mucosal defensive factors like enhanced mucin secretion and decreased cell shedding. As determined by radioimmunoassay, DW did not produce any change in the accumulation of PGE and PGI2, while HS increased them significantly in the human gastric mucosal incubates compared to NS. However, in the incubates of human colonic mucosa, both DW and HS showed a significant increase in PGE with a tendency to increase in PGI2 accumulation.

Chemoprevention of familial adenomatous polyposis development in the APC(min) mouse model by 1,4-phenylene bis(methylene)selenocyanate

Epidemiological and experimental studies have suggested that dietary supplementation with selenium can inhibit the development of cancers at several organ sites. We have consistently shown that 1, 4-phenylene bis(methylene) selenocyanate (p-XSC) is a highly effective cancer chemopreventive agent against the development of chemically induced cancers in several laboratory animal species. This is the first report describing the preventive effects of p-XSC in an animal model of familial adenomatous polyposis (FAP) containing a germline mutation of the APC gene. Six-week old male (heterozygous) C57BL/6J-APC(min) or wild-type mice were fed high fat diets containing 0, 10 or 20 p.p.m. p-XSC. After 80 days, the mice were killed and their intestines were excised and evaluated for polyps. Multiple samples were also harvested from normal appearing small intestine and colon for molecular analysis. Both the mucosa and polyps from the intestine and colon were assayed for beta-catenin, cyclooxygenase (COX)-2 expression and COX isoform activities. Administration of p-XSC in the diet significantly decreased the rate of formation of small intestinal tumors (P < 0. 0001) and colon tumors (P < 0.002) in APC(min) mice. p-XSC produced a dose-dependent inhibition of tumors in both small intestine (P < 0. 0001) and colon (P < 0.035). Mice fed 20 p.p.m. p-XSC had significantly lower levels of beta-catenin expression and COX-2 activity in polyps. These observations demonstrate for the first time that the synthetic organoselenium compound p-XSC possesses antitumor activity against genetically predisposed neoplastic lesions, such as FAP. While the exact mechanism(s) for this antitumor activity of p-XSC remains to be elucidated, it appears that modulation of beta-catenin expression and COX-2 activity is associated with inhibition of intestinal polyps.

Lack of chemopreventive efficacy of DL-selenomethionine in colon carcinogenesis

Epidemiologic observations and laboratory research have suggested that dietary selenium reduces the risk of colon cancer. Selenium-enriched brewer's yeast as a dietary supplement reduces the incidence of and mortality from cancer of the colon in humans. It is not clear whether the observed inhibitory effect is due to selenomethionine, or to other forms of selenium, or to a mixture of the selenium compounds present in selenium-enriched brewer's yeast. Therefore, bioassay described in this study examined the chemopreventive efficacy of 10 and 15 ppm selenomethionine, equivalent to 3.6 and 5.4 ppm as selenium, against azoxymethane (AOM)-induced colon carcinogenesis. At five weeks of age, groups of male F344 rats were fed diets containing 0 (control diet), 10 or 15 ppm selenomethionine. At seven and eight weeks of age, all rats except those in vehicle-treated groups received s.c. injections of AOM at a dose rate of 15 mg/kg body wt. The rats were maintained on their respective diets for 52 weeks and were then sacrificed. Colon tumors were processed and evaluated histopathologically. Colon tumor incidence and multiplicity were analyzed statistically. No obvious toxic effects were observed following dietary administration of 10 or 15 ppm selenomethionine as indicated by body weight gain. Administration of 10 or 15 ppm selenomethionine had no significant effect on colon tumor incidence and multiplicity. This study suggests that i) selenomethionine lacks chemopreventive efficacy against AOM-induced colon carcinogenesis and ii) other forms of selenium or a mixture of selenium compounds present in selenium-enriched brewer's yeast need to be evaluated for their chemopreventive efficacy.

Mechanisms in the chemoprevention of colon cancer: modulation of protein kinase C, tyrosine protein kinase and diacylglycerol kinase activities by 1,4-phenylenebis-(methylene)selenocyanate and impact of low-fat diet

Epidemiological and experimental studies suggest an inverse relationship between the intake of dietary selenium and/or low fat-intake and colon cancer risk. Efficacy studies in rodents suggest that the organoselenium compound 1, 4-phenylenebis(methylene)selenocyanate (p-XSC), is a more effective and less toxic chemopreventive agent than other organic or inorganic selenium compounds such as selenomethionine and Na2SeO3. The efficacy of p-XSC against colon cancer is significantly augmented by a low-fat diet. To explore the mechanisms by which this combined inhibiting effect against colon carcinogenesis comes about, we have investigated protein kinase C (PKC), tyrosine protein kinase (TPK), diacylglycerol kinase (DGK) activities and 8-isoprostane levels in colonic mucosa and tumor tissues in an azoxymethane (AOM)-induced rat colon cancer model. Weanling male F344 rats were fed the semipurified AIN-76A diet until seven weeks of age. Then various experimental groups were fed the low- or high-fat diets containing 0 or 20 ppm p-XSC (10 ppm as selenium). At seven weeks of age, groups of rats were injected s.c. with azoxymethane (AOM; 15 mg/kg body wt., once weekly for 2 weeks) and continued on their respective experimental diets until 38 weeks after the second AOM treatment. They were then sacrificed and colonic mucosal and tumor samples were evaluated for PKC, TPK, DGK and 8-isoprostane levels. Administration of p-XSC along with a low-fat diet significantly inhibited Ca+2-dependent and -independent PKC (P<0.05-0.01) activities in colonic mucosa and tumors. Administration of p-XSC either low-fat or high-fat diet significantly suppressed both colonic mucosal and tumor TPK activity (P<0.05-0.01). Suppression of TPK activity was more pronounced in rats maintained on a low-fat diet containing p-XSC. In contrast, rats receiving p-XSC with either low- or high fat diet showed significantly increased DGK activity (P<0.01-0.0001). Rats fed low-fat or high-fat plus p-XSC had lower-levels of 8-isoprostane in the colonic tumors than animals who had been given low- or high-fat diets without the organoselenium compound. Interestingly, 8-isoprostane levels were lower in the colon tumors of the rats fed the low-fat diet than those fed the high-fat diet. Our findings suggest that p-XSC induced down-regulation of PKC and TPK activities and up-regulation of DGK activity. These events may in part be responsible for the chemopreventive activity against colon carcinogenesis. Further, this study implies that p-XSC with a low-fat dietary regimen will augment regulation of PKC, TPK and DGK activities in the colon.

Presence of a Gs alpha mutation in an adrenal tumor expressing LH/hCG receptors and clinically associated with Cushing's syndrome

We describe the case of a patient with Cushing's syndrome due to a functioning adrenal adenoma. There was a pronounced increase in serum and urinary cortisol after administration of human chorionic gonadotropin. Immunocytochemistry revealed positive immunostaining for LH/hCG receptors. Molecular analysis documented the presence of a gsp mutation at codon 201 (CGT to TGT). The existence of this type of hCG-responsive adrenal tumor may help explain the higher prevalence of cortisol-secreting adrenal tumors versus pituitary-dependent disease in pregnant women with Cushing's syndrome as well as some reported cases of remission following delivery.

Chemoprevention of colon cancer by specific cyclooxygenase-2 inhibitor, celecoxib, administered during different stages of carcinogenesis

Epidemiological observations and laboratory research have suggested that nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the risk of colon cancer and that the inhibition of colon carcinogenesis by NSAIDs is mediated through the modulation of prostaglandin production by rate-limiting enzymes known as cyclooxygenases (COXs). Because traditional NSAIDs inhibit both COX-1 and COX-2, these drugs induce side effects, such as gastrointestinal ulceration and renal toxicity, through the inhibition of the constitutive COX-1. Overexpression of COX-2 has been observed in colon tumors; therefore, specific inhibitors of COX-2 could serve as chemopreventive agents. Our previous study has shown that celecoxib, an inhibitor of COX-2, while sparing COX-1, inhibited azoxymethane (AOM)-induced colon tumorigenesis when administered during both initiation and postinitiation stages, ie., celecoxib administered continuously before, during, and after carcinogen treatment. This study examined the dose-response effect of celecoxib when administered during the initiation and postinitiation stages. In addition, the chemopreventive effects of high-dose celecoxib administered during the promotion/progression stage of colon carcinogenesis, ie., continuous celecoxib administration beginning 14 weeks after the carcinogen treatment, was determined in male F344 rats. We also measured the steady-state levels of celecoxib in the plasma of animals given this inhibitor. Groups of 5-week-old male F344 rats were fed either a control diet or experimental diets containing 500, 1000, or 1500 ppm celecoxib. At 7 and 8 weeks of age, rats scheduled for carcinogen treatment were injected s.c. with AOM at a dose rate of 15 mg/kg body weight/week. Groups of animals destined for the promotion/ progression study and initially receiving the control diet were switched to a diet containing 1500 ppm celecoxib beginning 14 weeks after the second AOM treatment. All rats remained on their respective dietary regimens until the termination of the study, ie., 52 weeks, and were then sacrificed. Colon tumors were evaluated histopathologically. Administration of 500, 1000, or 1500 ppm celecoxib during the initiation and postinitiation stages significantly inhibited the incidence (P < 0.01 to P < 0.0001) as well as the multiplicity (P < 0.01 to P < 0.0001) of adenocarcinomas of the colon in a dose-dependent manner. Importantly, administration of 1500 ppm celecoxib during the promotion/progression stage also significantly suppressed the incidence and multiplicity of adenocarcinomas of the colon (P < 0.01). Also, administration of celecoxib to the rats during the initiation and postinitiation periods and throughout the promotion/progression stage strongly suppressed colon tumor volume (P < 0.0002 to P < 0.001). The steady-state plasma concentration of celecoxib increases somewhat with the dose. Thus, in this model system, the chemopreventive efficacy of celecoxib is dose-dependent when this COX-2 inhibitor is administered during the initiation and postinitiation periods. This study provides the first evidence that celecoxib is also very effective when it is given during the promotion/progression stage of colon carcinogenesis, indicating that the chemopreventive efficacy is achieved during the later stages of colon tumor development. This suggests that celecoxib may potentially be an effective chemopreventive agent for the secondary prevention of colon cancer in patients with familial adenomatous polyposis and sporadic polyps.

HCG concentration and receptor gene expression in placental tissue from trisomy 18 and 21

Trisomy 21 is associated with high maternal serum concentrations of intact human chorionic gonadotrophin alpha(HCG) and free beta-HCG whereas these concentrations are markedly decreased in trisomy 18. In this study, we investigated the effect of trisomy 21 and 18 on endogenous HCG concentrations and luteinizing hormone (LH)/HCG receptor expression in placental villous tissue in eight trisomy 21, six trisomy 18 and 42 chromosomally normal samples, collected at 12-16 weeks gestation. The tissue concentrations of intact HCG, free alpha-HCG and free beta-HCG subunits were measured using solid-phase two-site immunoradiometric assay. LH/HCG receptor expression was evaluated with immunohistochemistry and in-situ hybridization. Villous tissue in trisomy 21 contained higher beta-HCG concentrations than the controls (P < 0.05). In trisomy 18 cases, the beta-HCG concentration was lower than in the control group (P < 0.01). Both immunocytochemistry and in-situ hybridization demonstrated a more intense staining of the trophoblast in cases of trisomy 21 and 18, compared with controls with the strongest signal in cases of trisomy 18 (P < 0.01). We concluded that in trisomy 21 the high tissue HCG concentration and expression of LH/HCG receptor in the trophoblast may reflect the relative immaturity of the trophoblastic tissue whereas in trisomy 18, the very low concentration of endogenous HCG, associated with an over-expression of LH/HCG receptor in the trophoblast, is probably secondary to the poor differentiation of the cytotrophoblast.

Immortalized hippocampal cells contain functional luteinizing hormone/human chorionic gonadotropin receptors

We used immortalized HN33p cells as surrogates for hippocampal neurons to investigate the functional importance of luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptors. The use of various detection techniques demonstrated that HN33p cells contain LH/hCG receptor transcripts and receptor protein that can bind 125I-hCG. Culturing them with highly purified hCG resulted in a significant, although modest, dose-and time-dependent and hormone specific increase in steady state 5-lipoxygenase (5-LO) mRNA and protein levels. The studies on signaling revealed that treatment of HN33p cells with hCG resulted in a robust dose- and a time-dependent significant increase in media cyclic AMP levels. In addition, treatment with a protein kinase (PK)A inhibitor, isoquinolinesulfonamide (H-89), but not with a PKC inhibitor, bisindolylmaleimide (Bis), prevented hCG from increasing the 5-LO protein levels. Pretreatment of HN33p cells for 48 hrs with 2 microM antisense, but not sense, phosphorothioate oligodeoxy-nucleotides (ODN) synthesized from mouse LH/hCG receptor sequence resulted in a dramatic decrease in LH/hCG receptor protein levels. In the antisense, but not in sense, ODN-treated cells, hCG was unable to increase cyclic AMP and 5-LO protein levels, suggesting that receptors are required for hCG to work in HN33p cells.

A toxicity study of simultaneous administration of Tamoxifen and Diazepam to female Wistar rats

Tamoxifen (TAM) is used in the treatment of breast cancer and decreases the incidence of breast cancer when given to healthy women for different therapeutic purposes. This expansion of its use calls for further studies of its own potential side effects and those in combination with other prescription drugs. Diazepam (DP) is one such drug normally administered to patients who are under cancer treatment and those who suffer from insomnia. The present study examines the effect of individual and simultaneous administration of TAM and DP at therapeutic dose level of 0.8 mg/Kg/day of TAM and 0.3 mg/Kg/day of DP to normal female Wistar rats for a period of 12 weeks. The drugs were administered orally by mixing it in pellet made by wheat dough. There was no significant change in the terminal body weight and liver weights of animals. The ovary weights in TAM + DP treated animals were significantly decreased. The serum succinate dehydrogenase (SDH) levels were significantly lower in TAM, DP and TAM + DP treated rats and comparatively were lowest in TAM and TAM + DP treated animal groups. Serum glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT), acid and alkaline phosphatase (ACP & ALP) levels were significantly higher in the three treated groups, but comparatively lower in TAM + DP treated animals when compared to TAM or DP alone treated rats. There was marked increase in liver triglyceride and cholesterol levels in the three treated groups but remarkable decrease in liver glycogen. Total serum cholesterol levels were significantly high in DP and TAM + DP treated rats and total serum triglyceride levels were significantly high only in TAM treated rats. As a whole it can be concluded that DP does not enhance TAM toxicity on simultaneous administration, but on its own when administered individually brings about perturbation in lipid storage and metabolism.

Lovastatin augments sulindac-induced apoptosis in colon cancer cells and potentiates chemopreventive effects of sulindac

BACKGROUND & AIMS

3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (HRIs) were found incidentally to reduce new cases of colon cancer in 2 large clinical trials evaluating coronary events, although most patients in both treatment and control group were taking nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs are associated with reduced colon cancer incidence, predominantly by increasing apoptosis. We showed previously that lovastatin induces apoptosis in colon cancer cells. In the present study we evaluated the potential of combining lovastatin with sulindac for colon cancer chemoprevention.

RESULTS

Lovastatin, 10-30 micromol/L, augmented sulindac-induced apoptosis up to 5-fold in 3 colon cancer cell lines. This was prevented by mevalonate (100 micromol/L) or geranylgeranylpyrophosphate (10 micromol/L) but not farnesylpyrophosphate (100 micromol/L), suggesting inhibition of geranylgeranylation of target protein(s) as the predominant mechanism. In an azoxymethane rat model of chemical-induced carcinogenesis, the total number of colonic aberrant crypt foci per animal (control, 161 +/- 11) and the number of foci with 4+ crypts (control, 40 +/- 4.5) decreased to 142 +/- 14 (NS) and 43 +/- 2.9 (NS), respectively, with 50 ppm lovastatin alone; to 137 +/- 5.4 (P = 0.053) and 36 +/- 2.1 (NS) with 80 ppm sulindac alone; and to 116 +/- 8.1 (P = 0.004) and 28 +/- 3.4 (P = 0.02) when 50 ppm lovastatin and 80 ppm sulindac were combined.

CONCLUSIONS

Addition of an HRI such as lovastatin may augment chemopreventive effects of NSAIDs or/and may allow lower, less toxic doses of these drugs to be used.

Human chorionic gonadotropin exhibits potent inhibition of preterm delivery in a small animal model

OBJECTIVE

The purpose of this study was to test the capability of human chorionic gonadotropin to inhibit prostaglandin-induced preterm delivery in a murine model.

STUDY DESIGN

A preterm delivery model was developed by using intraperitoneal injection of 20 microgram of prostaglandin F(2)(alpha) to induce preterm labor in C3H/HeN inbred mice. Mice were then pretreated with human chorionic gonadotropin 4 hours before administration of prostaglandin F(2)(alpha), and time to delivery of the first pup was recorded. After initial promising results, mice were then given increasing intraperitoneal doses of human chorionic gonadotropin (100 IU, 250 IU, or 1000 IU or sodium chloride solution vehicle) 4 hours after administration of prostaglandin F(2)(alpha). The specificity of the human chorionic gonadotropin effect was assessed by treating mice with whole human chorionic gonadotropin, an equal mass dose of the beta-subunit or the alpha-subunit of human chorionic gonadotropin, or an equal mass dose of luteinizing hormone 4 hours after administration of prostaglandin F(2)(alpha). Delivery times between groups were compared by using the Mann-Whitney U test and the log-rank test. Survival estimates were computed by using the Kaplan-Meier method.

RESULTS

Pilot studies in 52 mice confirmed that a single intraperitoneal injection of 20 microgram of prostaglandin F(2)(alpha) on day 16 (80% gestation) consistently induced preterm delivery compared with the effect of sodium chloride solution on control mice (prostaglandin F(2)(alpha), 19.3 +/- 2.9 hours; sodium chloride solution, 53.5 +/- 13.6 hours; P <.0001). Mice pretreated with human chorionic gonadotropin (1000 IU) demonstrated significant delays in delivery times compared with the prostaglandin-only group (prostaglandin F(2)(alpha) only, 21.9 +/- 2. 0 hours; human chorionic gonadotropin pretreatment plus prostaglandin F(2)(alpha), 48.5 +/- 20 hours; P <.0001; n = 17). Mice treated with human chorionic gonadotropin (100 IU, 250 IU, 1000 IU) 4 hours after administration of prostaglandin F(2)(alpha) demonstrated significant dose-dependent inhibition of preterm delivery compared with the prostaglandin-only group (P <.00005; n = 34). Mice treated with the alpha-subunit or the beta-subunit of human chorionic gonadotropin after prostaglandin administration did not demonstrate delays in delivery times (P =.46; n = 27). Administration of luteinizing hormone delayed delivery compared with the effect of prostaglandin F(2)(alpha) on control animals (P <.05; n = 17); however, the effect was less pronounced than that seen with a mass equivalent of human chorionic gonadotropin.

CONCLUSIONS

Human chorionic gonadotropin exhibits potent inhibition of prostaglandin-induced preterm delivery in mice. The effect is dose-dependent, and whole human chorionic gonadotropin is required to elicit inhibition. Further studies are needed to determine the safety and efficacy of human chorionic gonadotropin as a potential therapy for preterm labor inhibition in human pregnancy.

Solitary plasmacytoma presenting as peripheral neuropathy: a case report

We report a 26 year old woman presenting with a chronic predominantly motor radiculoneuropathy. A biopsy proven solitary lytic plasmacytoma was detected in the left sixth rib. Serum immunoelectrophoresis revealed 'M' band (IgG, l light chain). Excision of the plasmacytoma resulted in gradual but steady recovery. We suggest that all patients with 'cryptogenic' polyneuropathy be investigated for this potentially treatable condition. A high index of suspicion assists the organization of appropriate diagnostic investigations.

Treatment of human endometrial gland epithelial cells with chorionic gonadotropin/luteinizing hormone increases the expression of the cyclooxygenase-2 gene

Endometrial glands contain higher levels of LH/hCG receptors than other cells in the human uterus. The present study investigated their functional importance. Northern and Western blotting and covalent receptor cross-linking demonstrated that human endometrial gland epithelial cells in culture contained multiple LH/hCG receptor transcripts and an 80-kDa receptor protein that can bind [125I]hCG in a hormone-specific manner. Culturing cells with highly purified hCG resulted in a time- and dose-dependent increase in steady state levels of cyclooxygenase-2 (COX-2) messenger ribonucleic acid and protein and the secretion of PGE2. Although human LH could mimic hCG, FSH, TSH, and alpha- or beta-subunits of hCG had no effect on COX-2 protein levels. Studies on signaling revealed that treatment of cells with hCG resulted in an increase in cAMP levels and protein kinase A (PKA) activity. Inhibition of PKA activity by cotreatment with isoquinoline-sulfonamide (H-89) prevented hCG from increasing COX-2 protein levels. Treatment with 8-bromo-cAMP mimicked the effect of hCG, and cotreatment with a selective inhibitor of type I PKA, 8-chloro-cAMP, prevented 8-bromo-cAMP and hCG from increasing COX-2 protein levels. The requirement of receptors for LH/hCG action was investigated by 24-h treatment of human endometrial gland epithelial cells with 21-mer phosphorothioate oligodeoxynucleotides (ODNs) synthesized from human receptor sequence. Treatment with 2 micromol/L antisense, but not sense, ODN resulted in a dramatic reduction in LH/hCG receptor protein levels. hCG was unable to increase COX-2 protein, PGE2, and cAMP levels in an antisense, but not in sense, ODN-treated cells. In summary, we conclude that hCG and LH treatment can increase expression of the COX-2 gene in human endometrial gland epithelial cells. The effect was time and dose dependent, hormone specific, and mediated by the cAMP/type I protein kinase A signaling pathway. The hCG actions require a normal complement of its receptors in cells. These hCG and LH effects may be another action of these hormones in human endometrium that is important for implantation of the blastocyst and continuation of pregnancy.

Chemopreventive effect of S-methylmethane thiosulfonate and sulindac administered together during the promotion/progression stages of colon carcinogenesis

S-methylmethane thiosulfonate (S-MMTS), isolated from cauliflower and having antiproliferative activity, and the non-steroidal anti-inflammatory drug sulindac have been shown to inhibit chemically induced colon carcinogenesis when they are administered during the initiation and/ or post-initiation stages. The present study was designed to investigate the chemopreventive efficacy of 80 p.p.m. S-MMTS administered during the initiation and post-initiation stages and of S-MMTS and sulindac administered together at low doses (40 and 160 p.p.m., respectively) during the promotion/progression phases (late in the premalignant stage) of colon carcinogenesis. At 5 weeks of age, groups of male F344 rats were fed diets containing 0 (control diet) or 80 p.p.m. S-MMTS. At 7 and 8 weeks of age all rats except those in the vehicle-treated groups were given s.c. injections of 15 mg/kg body wt azoxymethane (AOM). Rats receiving the control diet and intended for the study of inhibition of colon carcinogenesis during the promotion/progression phases were continued on the control diet for 14 weeks after the second AOM treatment; they were then switched to experimental diets containing 80 p.p.m. S-MMTS, 160 p.p.m. sulindac or 40 p.p.m. S-MMTS plus 160 p. p.m. sulindac. The rats were maintained on their respective dietary regimens until 52 weeks after carcinogen treatment and were then killed. Colon tumors were evaluated histopathologically. Administration of 80 p.p.m. S-MMTS alone during the initiation and post-initiation stages and promotion/progression stages had no significant effect on colon tumor inhibition. In contrast, the administration of 160 p.p.m. sulindac during the promotion/progression stages did significantly inhibit total colon tumor multiplicity (P < 0.05). Moreover, co-administration of 40 p.p. m. S-MMTS with 160 p.p.m. sulindac during the promotion/progression stages suppressed the incidence and multiplicity of non-invasive adenocarcinomas (P < 0.05-0.01) and multiplicity of invasive and total adenocarcinomas of the colon to a significant degree (P < 0. 05-0.01). These findings have potential clinical implications.

Chemopreventive efficacy of sulindac sulfone against colon cancer depends on time of administration during carcinogenic process

Epidemiological and model studies with laboratory animals have provided evidence that nonsteroidal anti-inflammatory drugs reduce the risk of colon cancer. Sulindac, a nonsteroidal anti-inflammatory drug, has been shown to inhibit azoxymethane (AOM)-induced colon carcinogenesis in rats when administered continuously before, during, and after carcinogen treatment (initiation and postinitiation periods) or when given continuously beginning 14 weeks after carcinogen administration (promotion/ progression stage). The present study was designed to investigate the chemopreventive efficacy of sulindac sulfone (exisulind), the sulfone metabolite of sulindac, when administered during the promotion/progression stage of colon carcinogenesis in comparison to the effect during the initiation and postinitiation periods. We have also studied the modulating effect of exisulind on colonic tumor apoptosis. At 5 weeks of age, groups of male F344 rats were fed diets containing 0%, 0.06%, and 0.12% exisulind. At 7 weeks of age, groups of animals were injected s.c. with AOM (15 mg/kg body weight, once weekly for 2 weeks). Animals intended for the promotion/progression study and receiving 0% exisulind were switched to an experimental diet containing 0.12% exisulind at 14 weeks after the second AOM treatment. All rats remained on their respective dietary regimens until the termination of the study, 50 weeks after the second AOM injection. Colon tumors were evaluated histopathologically for tumor type. Administration of 0.06% and 0.12% exisulind during the initiation and postinitiation periods significantly inhibited the incidence and multiplicity of invasive and/or noninvasive adenocarcinomas of the colon. The inhibition of colon tumorigenesis by exisulind was associated with a significant retardation of body weight gain shortly after sulfone administration and increased apoptosis in the colon tumors. In contrast, administration of the higher dose (0.12%) of exisulind during the promotion/progression stage had only minimal effects on colon tumorigenesis and apoptosis in the colon tumors, suggesting that early administration, but not late administration, may be required for chemopreventive efficacy of this drug.

Opioid peptides inhibit the action of oestradiol on human myometrial cells in culture

The effect of opioid peptides on cultured, oestradiol-stimulated human myometrial cells was examined. Oestradiol increased cell densities in mixed-cell (smooth muscle cells + stromal fibroblasts) cultures by 40%. This oestradiol-induced stimulation of cell proliferation was decreased to control values by D-met2-pro5-enkephalinamide. The half-effective inhibitory concentration of enkephalinamide was 0.3 nmol/l. The opioid-induced inhibition of cell proliferation was blocked completely by the specific opiate receptor antagonist naloxone, while naloxone did not have any effect on its own. This opioid effect was mediated dominantly by the mu opiate receptor. The optimal concentration for oestradiol to stimulate uterine cell proliferation was 2.2 nM. The basal rate of cell proliferation was not affected by enkephalinamide. In saturation experiments, the parameters of specific [3H]-naloxone binding were: dissociation constant = 1.02 nM, maximal binding capacity = 2910 binding sites/cell, Hill coefficient = 1.029. In human myometrial pure smooth muscle cell cultures, oestradiol decreased the proliferation of cells. Progesterone potentiated these oestradiol effects, but had no effect on its own. Enkephalinamide was also able to block the effects of oestradiol, but naloxone did not antagonize it. In summary, here we present a novel inhibitory role of endogenous opioid peptides in the regulation of cell growth and proliferation in the human uterus.

Prevention of colonic preneoplastic lesions by the probiotic Lactobacillus acidophilus NCFMTM in F344 rats

The experiments described here were aimed at developing novel probiotic strains that may aid in the reduction of colon cancer risk. We assessed the potential anticancer properties of Lactobacillus acidophilus NCFMTM in male F344 rats using inhibition of the formation of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in the colon as the measure of preventive efficacy. At 6 weeks of age, groups of rats were fed the experimental diets containing 0, 2% or 4% lyophilized cultures of L. acidophilus NCFMTM. At 7 weeks of age, all animals in each dietary group, except the vehicle-treated rats, were s.c. injected with AOM (15 mg/kg body weight) once weekly for two weeks. The vehicle-treated groups were given s.c. injections of normal saline. All rats were necropsied 10 weeks after the last AOM injection and ACF in formalin-fixed, methylene blue-stained colonic tissues were counted under the light microscope. The contents of the cecum were analyzed for bacterial beta-glucuronidase activity. Diet supplementation with the probiotic strain NCFMTM significantly suppressed AOM-induction of colonic ACF, in terms of total number, as well as crypt multiplicity and number of ACF/cm2 colon (P<0.01 - 0.001). NCFMTM inhibited AOM-induced colonic ACF formation in a dose-dependent manner (P<0.01). A significant dose-dependent reduction of cecal beta-glucuronidase activities was observed in the rats fed 2% (P<0.04) and 4% (P<0.0001) NCFMTM. These results suggest that Lactobacillus acidophilus NCFMTM may potentially prevent colon cancer development. Further studies are warranted to determine the full potential of this probiotic strain in preclinical efficacy studies.

Chemoprevention of colonic aberrant crypt foci by an inducible nitric oxide synthase-selective inhibitor

Inducible nitric oxide synthase (iNOS) is overexpressed in colonic tumors of humans and also in rats treated with a colon carcinogen. iNOS appear to regulate cyclooxygenase-2 (COX-2) expression and production of proinflammatory prostaglandins, which are known to play a key role in colon tumor development. Experiments were designed to study the inhibitory effects of S,S'-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea (PBIT) a selective iNOS-specific inhibitor, measured against formation of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF). Beginning at 5 weeks of age, male F344 rats were fed experimental diets containing 0 or 50 p.p.m. of PBIT, or 2000 p.p.m. of curcumin (non-specific iNOS inhibitor). One week later, rats were injected s.c. with AOM (15 mg/kg body wt, once weekly for 2 weeks). At 17 weeks of age, all rats were killed, colons were evaluated for ACF formation and colonic mucosa was assayed for isoforms of COX and NOS activities. Both COX and iNOS activities in colonic mucosa of the AOM-treated rats were significantly induced. Importantly, 50 p.p.m. PBIT suppressed AOM-induced colonic ACF formation to 58% (P < 0.0001) and crypt multiplicity containing four or more crypts per focus to 78% (P < 0.0001); it also suppressed AOM-induced iNOS activity. Curcumin inhibited colonic ACF formation by 45% (P < 0.001). These observations suggest that iNOS may play a key regulatory role in colon carcinogenesis. Developing iNOS-specific inhibitors may provide a selective and safe chemopreventive strategy for colon cancer treatment.

The inhibitory effect of hCG on counter current transfer of GnRH and the presence of LH/hCG receptors in the perihypophyseal cavernous sinus--carotid rete vascular complex of ewes

The existence of the hormone passage from venous blood into arterial blood in the area of the perihypophyseal vascular complex has been demonstrated in some mammals, but its mechanism has not been defined. To study the regulatory mechanism we infused hCG into perihypophyseal cavernous sinus of ovariectomized, conscious ewes to test if the hCG would affect putative LH/hCG receptors and inhibit counter-current transfer of GnRH from the venous cavernous sinus to the arterial carotid rete. The latter study was done on an isolated head model. Ewes were ovariectomized in mid-anestrus and, after 4 to 5 wk were used in the experiments. On the day of experiment ewes were treated intramuscularly with estradiol benzoate or oil vehicle, and 18 to 20 h later were infused either with a multielectrolyte solution or hCG for 2 h via the venae angularis oculi. Immediately thereafter the ewes were anesthetized and exanguinated, and subsequently decapitated. The isolated head was perfused with Dextran in multielectrolyte. The 125I-GnRH was infused into the cavernous sinus via the venae angularis oculi for 5 min; contemporaneous samples were taken from the carotid rete and both jugular veins at 1-min intervals. Transfer of 125I-GnRH from the cavernous sinus to the carotid rete was inhibited by hCG in ewes pretreated with estradiol benzoate but not with oil (P<0.005). We collected tissue samples from the vascular complex of the cavernous sinus and carotid rete of cyclic ewes to determine the presence of LH/hCG receptors. In situ hybridization showed the presence of LH/hCG receptor mRNA transcripts in the walls of both arterial and venous compartments of the cavernous sinus-carotid rete complex, and immunohistochemistry revealed the presence of receptor proteins. These novel findings confirm previously obtained data suggesting that LH is a modulatory factor for the counter-current transfer of neuropeptides from the venous blood of the cavernous sinus to the arterial blood supplying the brain and hypophysis. The LH could modulate 125I-GnRH transfer acting directly on the vascular smooth muscle.