Protection against atherosclerosis by estrogen is independent of plasma cholesterol levels in LDL receptor-deficient mice.

Low density lipoprotein (LDL) receptor-deficient (LDLR-/-) mice consuming a high fat diet were used to assess the effect of endogenous and exogenous estradiol (E2) on atherosclerosis. Sexually mature female mice were ovariectomized (OVX) and implanted with subcutaneous, slow-release pellets designed to release 6 microg/day of exogenous 17beta-estradiol (17beta-E2 ), 17alpha-estradiol (17alpha-E2 ), or placebo (E2- deficient). Sham-operated control female (endogenous E2 ) and male mice were studied as controls. Aortic atherosclerotic lesion area was reduced by physiologic amounts of both endogenous and exogenous E2 compared to E2-deficient female mice. Although plasma cholesterol levels were reduced by exogenous E2 despite the absence of the LDL receptor, endogenous E2 was not associated with any cholesterol changes. In contrast, only 17alpha-E2 was associated with decreased fasting triglyceride. In subgroup analyses matched for time-averaged plasma total cholesterol, aortic lesion area was reduced by the presence of estradiol (E2 ). E2 protected LDLR-/- female mice from atherosclerosis and this protection was independent of changes in plasma cholesterol levels.

Endometrial endothelin: regulator of uterine bleeding and endometrial repair.

1. Endothelin (ET) and its mRNA are present in endometrium. Expression of ET varies across the menstrual cycle, reaching maximal levels in the premenstrual phase, suggesting a paracrine role in endometrial bleeding and/or repair. 2. The major cellular source of ET is the epithelium, although endothelium and decidualized stroma are additional sites of production. Epithelial ET is the ET-1 isoform and this is able to contract rat thoracic aortic rings ex vivo. 3. Endothelin-1 production by cultured endometrial epithelial cells is markedly increased by serum and, to a lesser extent, by transforming growth factor-beta and interleukin-1 alpha, but not by epidermal growth factor, oxytocin, arginine vasopressin, thrombin or angiotensin II, which stimulate ET production in other tissues. 4. Endothelin-1 has mitogenic actions on endometrial stromal cells; it stimulates the uptake of [3H]-thymidine, acting via the AP-1 cis element c-jun. 5. Neutral endopeptidase (NEP), a membrane-bound ectoenzyme that is capable of degrading ET, is localized principally in endometrial stroma and immunoreactivity is maximal in the secretory phase of the cycle. 6. A potential role for ET in regulating endometrial bleeding is suggested by studies on endometrium from two groups of women who were experiencing abnormal uterine bleeding: users of the contraceptive Norplant (Leiras Co., Turku, Finland) and subjects with documented menorrhagia. In both groups, ET-1 immunoreactivity in endometrial epithelium was markedly reduced compared with the normal menstrual cycle and did not vary cyclically, while NEP immunoreactivity, particularly in the epithelium, was increased. Thus, ET may be involved in endometrial bleeding, as a vasoconstrictor before the onset of menstruation when vasoconstriction is intense and, subsequently, when it may be required in the cessation of menstrual bleeding. Furthermore, the mitogenic actions of ET may play a role in endometrial regeneration and remodelling during the menstrual cycle, particularly following menstruation.

Endothelin and neutral endopeptidase in the endometrium of women with menorrhagia.

The mechanisms underlying excessive menstrual bleeding or menorrhagia are not understood. In view of its potent vasoconstrictor and growth factor properties, endothelin has been proposed to have a potential paracrine role in the regulation of uterine blood flow and therefore could be a factor in menorrhagia. We compared the cellular localization of endothelin and its metabolizing enzyme, neutral endopeptidase, in endometrial biopsies from women with documented menorrhagia and in those with a normal menstrual cycle. Menorrhagia was documented by measurement of menstrual blood loss, 146 +/- 141 ml (median +/- SD). Endothelin and neutral endopeptidase were localized by immunohistochemistry, and the staining intensity was graded. Their immunostaining patterns were found to differ in menorrhagia compared to the normal menstrual cycle. Endothelin was reduced in glandular epithelium in menorrhagia and did not vary cyclically, while neutral endopeptidase was increased in the glandular epithelium. In menorrhagia, stromal endothelin immunoreactivity was not different from the normal cycle and although neutral endopeptidase immunostaining in stroma was similar to the secretory phase of normal endometrium, cyclical variation was absent. The potential for increased metabolism of endothelin could be an explanation for the decreased endothelin immunostaining in the glandular epithelium.

Endothelin and menstruation.

Endothelin (ET) and its mRNA are present in human endometrium. Its expression varies across the menstrual cycle, reaching maximal levels in the pre-menstrual phase. Human endometrial epithelial cells are the major in-vitro source of ET, and its release is affected by the stage of the menstrual cycle from which the endometrium is taken and by the cytokines transforming growth factor-beta 1 and interleukin-1 alpha. The cyclical variation in both ET mRNA and protein expression across the normal menstrual cycle, and the differences observed in abnormal uterine bleeding (specifically reduced immuno-reactivity in luminal and glandular epithelium in the endometrium of Norplant users), are consistent with a role for ET in the control of menstrual bleeding. The role of epithelial cell ET is not yet understood. Whether this source of ET is important in endometrial regeneration and repair following menstruation or in vaso-constriction to cease menstrual bleeding remains to be determined.

Cross-reactivity of Shigella flexneri serotype 2a O antigen antibodies following immunization or infection.

To study the cross-reactivity pattern of Shigella flexneri 2a O-antigen antibodies, sera from humans and monkeys challenged with S. flexneri 2a, and from humans and guinea pigs immunized with a recombinant vaccine expressing serotype 2a O-antigen, were tested against a panel of lipopolysaccharide extracted from heterologous S. flexneri. Sera from the two groups of humans, who were volunteers in either a clinical challenge or vaccination study, showed similar patterns: cross-reactivity was more often seen with IgA antibodies, and these were mostly cross-reactive with serotype 2b, which shares the type II antigen, and serotypes 1a, 5a, and Y, which share 4 or 3, 4 group antigen, with 2a. The majority of sera from immunized guinea pigs showed both IgG and IgA cross-reactivity with 1a, 5a, and Y, but not 2b. The majority of sera from challenged monkeys showed cross-reactivity with almost all flexneri serotypes tested, with 1a, 2b, and Y being recognized most often, and the cross-reactive antibodies were more often IgG than IgA. These results show that either immunization or challenge with the 2a serotype induces cross-reactive antibodies which recognize similar subsets of heterologous serotypes, and suggest that it may be possible to design multivalent vaccines against S. flexneri.

Leukaemia inhibitory factor in human endometrium throughout the menstrual cycle.

Leukaemia inhibitory factor (LIF) is a pleiotropic cytokine previously demonstrated to be essential for blastocyst implantation in mice. Samples of endometrium from normal cyclic women throughout the menstrual cycle were tested for LIF messenger RNA by Northern blot analysis and the corresponding protein was localised immunohistochemically with a polyclonal antibody to LIF. Western blot analysis detected a 45 kDa LIF protein in an extract from late secretory tissue. The expression of LIF messenger RNA transcript was detected only during the mid and late secretory phases of the cycle after day 20. Immunoreactive LIF was observed in all human endometrial samples. In the stroma there were moderate to high levels of immunohistochemical staining throughout the cycle with considerable variation between individuals but no cyclical variation. Epithelial staining, both luminal and glandular, was also present throughout the cycle but this was relatively low in the proliferative phase and strongest in the mid to late secretory phases. The marked cyclical changes of immunoreactive LIF in the human endometrial epithelium suggest a paracrine/autocrine role for LIF in endometrial function. Whether LIF is essential for implantation in the human remains to be established.

Immunolocalization of endothelin and neutral endopeptidase in the endometrium of users of subdermally implanted levonorgestrel (Norplant).

Subdermally implanted slow-release levonorgestrel (Norplant), a widely used effective contraceptive, has a high rate of discontinuation due to unacceptable menstrual bleeding disturbances. Endothelin (ET), a potent vasoconstrictor, varies across the menstrual cycle in normal endometrium. It has been proposed that ET has a potential paracrine role in the regulation of uterine blood flow. Neutral endopeptidase (NEP), a membrane-bound ecto-enzyme, can inactivate ET and is localized principally in endometrial stroma. We have compared the immuno-localization of ET and NEP in endometrial biopsies from Indonesian women using Norplant with normal controls. Differences were observed in the glandular and luminal epithelium of Norplant-treated subjects, where ET immunostaining was low while NEP immunoreactivity was increased. The latter may represent a local increase in enzyme activity, potentially explaining the reduced ET immunoreactivity. There was no correlation of ET immuno-reactivity with the duration of implant use or total number of bleeding days. The marked differences in the ET immunostaining pattern in Norplant users, with their increased risk of abnormal uterine bleeding, suggest that ET may be important in controlling menstrual bleeding. Whether endometrial epithelial cell ET has a role as a mitogen in endometrial repair and regeneration, or as a vasoconstrictor important in the cessation of bleeding following menstruation, remains to be determined.

PIP: In Indonesia, 107 women requesting insertion of the contraceptive implant system Norplant at the Klinik Raden Saleh in Jakarta kept a daily menstrual diary for 90 days before endometrial biopsy and allowed venous blood samples to be taken six times in the two-week period also before endometrial biopsy so researchers could examine the roles of endothelin (ET) and neutral endopeptidase (NEP) in menstrual bleeding changes in women using Norplant. They compared the degree of immunostaining in the endometrial biopsy samples of these women with those of 55 controls, most of which came from women in Melbourne, Australia. The endometrium of the Norplant group exhibited low glandular and luminal epithelial ET immunostaining as did the normal endometrium during the proliferative phase. Glandular epithelial ET immunostaining in the Norplant group fell considerably during the secretory or menstrual phases, however. NEP immunoreactivity was greater in the endometrium of Norplant users than in that of controls, suggesting that enzyme activity may have been increased locally among Norplant users. This increase may have accounted for the low ET reactivity. ET immunoreactivity was not related to duration of implant use or total number of bleeding days. These findings indicate that, since Norplant users are at an increased risk of abnormal uterine bleeding, ET may control menstrual bleeding. It is not known whether ET acts as a mitogen in endometrial repair and regeneration or as a vasoconstrictor to stop bleeding after menstruation.

Pain relief and quality-of-life assessment following intravenous and oral clodronate in hormone-escaped metastatic prostate cancer.

OBJECTIVE: To establish the efficacy of intravenous clodronate followed by maintenance oral clodronate in patients with painful bone metastases resulting from hormone-resistant prostate cancer. PATIENTS AND METHODS: A multicentre open study of 27 patients assessed the efficacy of clodronate treatment by estimating the reduction in World Health Organization (WHO) Pain Score, the increase in WHO Performance Status and by a novel quality-of-life/activity score. RESULTS: Ten of 27 patients achieved significant pain relief after receiving 300 mg/day of intravenous clodronate for 10 days. This was matched by an improvement in the activity score and WHO Performance Status. Three of 27 patients continued to have relief from pain after 3 months of oral clodronate therapy. CONCLUSION: Intravenous clodronate therapy was effective in relieving the pain resulting from prostate cancer bone metastases in 10 of 27 patients but the benefit was shortlived. The use of a personal quality-of-life/activity questionnaire which assesses aspects of everyday life that are important to the patient may be more appropriate for patients with very advanced prostate cancer than are other quality-of-life questionnaires in current use.

The persistence of bacille Calmette-Guérin in the bladder after intravesical treatment for bladder cancer.

OBJECTIVE: To determine the incidence of bacille Calmette-Guérin (BCG) bacilli persisting in the urinary tract of patients treated previously with intravesical BCG for carcinoma in situ or multiple Ta.T1 transitional cell carcinoma. PATIENTS AND METHODS: One-hundred and twenty-five patients were treated at the Freeman Hospital, Newcastle upon Tyne, UK over an 8-year period, 90 of whom submitted early morning urine samples for culture for acid-fast bacilli at varying intervals following BCG treatment. The records of all patients were reviewed to determine the incidence of caseating granulomata containing acid-fast bacilli together with the incidence of toxicity and the outcome of treatment. RESULTS: Five patients were found to have persisting acid-fast mycobacteria in their urine or bladder up to 16.5 months after completing intravesical instillations of BCG. In one patient this probably accounted for bladder symptoms that required palliative cystectomy. In four patients the 'infection' was not severe. Two patients were treated with antituberculous chemotherapy without complication. Three years after intravesical BCG therapy 36 of 69 patients (52%) had remained tumour free. CONCLUSION: BCG organisms can persist in the urinary tract for at least 16.5 months after the completion of intravesical BCG instillation therapy.

Production and characterization of endothelin released by human endometrial epithelial cells in culture.

This study identified and characterized endothelin (ET) produced by human endometrial epithelial cells cultured under serum-free conditions, compared the ET released by cells derived from proliferative and secretory phase endometrium, and examined the regulation of ET released by these cells. ET messenger RNA was detected in normal human endometrium with maximal expression in the mid-late secretory phase. Immunoreactive ET released into culture media by separated endometrial epithelial and stromal cells was almost entirely of epithelial cell origin, consistent with the previous immunohistochemical findings. This was identified as ET-1 by reverse phase high-pressure liquid chromatography, and the fractionated conditioned media exhibited bioactivity similar to that of standard ET-1. Mean ET production was greater from cells derived from proliferative phase endometrium cultured either in serum (P < 0.02) or serum-free conditions (P < 0.02). Fetal calf serum stimulated ET-1 production from epithelial cells in a dose-responsive manner. ET production was also stimulated by transforming growth factor-beta 1 (2, 5 & 10 ng/mL) and IL-1 alpha (10 & 100 IU/mL) under serum-free conditions but always to a lesser extent than stimulation by serum. The production of ET in human endometrium underlines a potential role for ET in endometrial function.

Calculated properties of arene oxides of biological interest. 1. Molecular orbital examination of simple models.

The INDO calculational formalism is shown to account for the relative ease of carbonium ion formation and for the variation in isomerization rates of some simple arene oxides. Transition-state energy differences provide a reasonable correlation with observed isomerization rates for benzene oxide, methyl-substituted benzene oxides, naphthalene 1,2-oxide, and phenanthrene 9,10-oxide.

Electronic structures of cephalosporins and penicillins. 4. Modeling acylation by the beta-lactam ring.

Molecular orbital calculations by the CNDO/2 method are used to study the molecular and electronic details involved in the initial phases of the opening of the beta-lactam ring of a model cephalosporin structure, 7-amino-3-acetoxymethyl-3-cephem. The effect of a simple nucleophile, OH-, approaching the carbonyl carbon center of the beta-lactam ring is monitored by following the charge redistributions that occur in the bicyclic system and in the 3 side chain. A migration of electron density to the ester oxygen of the CH2OAc group is observed with concomitant weakening of the CH2-OAc bond. The results are discussed in relation to the mechanism of acylation of bacterial cell wall enzymes by beta-lactam antibiotics and in relation to the hydrolysis of these molecules. The results indicate that the ability of the 3' substituent of cephalosporins to stabilize electron density transferred to it, i.e., the leavability of the 3' moiety, can be an important factor in activating the beta-lactam toward nucleophilic attack.