Synergistic Regulation of Cytosolic Ca2+ Concentration by Adenosine and alpha1-Adrenergic Agonists in Mouse Striatal Astrocytes

Adenosine has a broad array of actions on neurons but astrocytes also possess adenosine receptors. We have previously shown that adenosine, by acting on astrocytes in the striatum, can modulate neuronal responses mediated by receptors coupled to phospholipase C through an astrocyto - neuronal interaction. In addition, adenosine was found to potentiate the alpha1-adrenergic production of inositol phosphates in astrocytes. The mechanism involved in this potentiation was further investigated by examining the effects of adenosine and alpha1-adrenergic receptor agonists on cytosolic Ca2+ in cultured striatal astrocytes from the embryonic mouse in primary culture. When used alone, methoxamine, a selective agonist of alpha-adrenergic receptors or 2-chloroadenosine, a stable analogue of adenosine, induced a transitory increase in cytosolic Ca2+, but their combined addition led to a sustained increase in cytosolic Ca2+, which seems to be due to a Ca2+ influx, because it was not observed in the absence of external Ca2+. Voltage independent Ca2+ channels contribute to this process and different blockers of voltage-operated calcium channels, such as dihydropyridines, phenylalkylamines, La3+ or Co2+ were ineffective in suppressing the sustained cytosolic Ca2+ elevation. Three observations suggest the implication of arachidonic acid in the observed potentiation: (i) arachidonic acid induced a sustained elevation of cytosolic Ca2+ similar to that evoked by the coapplication of methoxamine and 2-chloroadenosine; (ii) the addition of arachidonic acid during the calcic plateau produced by the combined application of the agonists did not increase further cytosolic Ca2+ levels; (iii) in the presence of methoxamine, 2-chloroadenosine induced a release of arachidonic acid. The stimulation of phospholipase C and the resulting activation of protein kinase C induced by methoxamine seem to be required for the potentiating effect of 2-chloroadenosine on cytosolic Ca2+. In fact, the direct activation of protein kinase C by an exogenous diacylglycerol analogue mimicked the effect of methoxamine because, in this condition, 2-chloroadenosine alone evoked a sustained elevation of cytosolic Ca2+. Therefore, methoxamine, through the successive activation of phospholipase C and protein kinase C, could allow a lipase, probably phospholipase A2, to be stimulated by 2-chloroadenosine. Arachidonic acid has already been shown to trigger the opening of K+ channels and the formation of inositol phosphates in other cell types. Therefore, in striatal astrocytes, 2-chloroadenosine, through an arachidonic acid-mediated hyperpolarization, could increase the Ca2+ driving force and thus improve Ca2+ influx through inositol phosphate-gated channels. This hypothesis is further supported by the suppressing effect of a 50 mM KCI-induced depolarization on the long lasting elevation of cytosolic Ca2+ seen in the combined presence of 2-chloroadenosine and methoxamine.     

Compliance with consensus recommendations for systemic therapy is associated with improved survival of women with node-negative breast cancer.

PURPOSE: The impact of consensus recommendations for systemic therapy on outcome of disease is unclear. We evaluated if compliance with guidelines for systemic adjuvant treatment is associated with improved survival of women with node-negative breast cancer. PATIENTS AND METHODS: The study population included women diagnosed with invasive node-negative breast cancer in Québec, Canada, in 1988 to 1989, 1991 to 1992, and 1993 to 1994. Information was collected by chart review, linkage with administrative databases, and queries to attending physicians. Guidelines from the 1992 St Gallen conference were used as standard of care. Survival was estimated by Kaplan-Meier and Cox proportional hazards analyses. RESULTS: Among 1,541 women, 358 died before December 1999. Median follow-up was 6.8 years. Seven-year event-free and overall survivals were 66% and 81%, respectively. Survival was 88%, 84%, and 74% in women at minimal, moderate, or high risk of recurrence. Virtually all women at minimal risk were treated according to the consensus (98.4% of 370). In comparison, adjusted hazard ratios of death were 1.0 (95% CI, 0.6 to 1.7) and 2.3 (95% CI, 1.3 to 4.0) among women at moderate risk treated according to the consensus or not, respectively. Among women at high risk, adjusted hazard ratios of death were 2.0 (95% CI, 1.4 to 2.8) and 2.7 (95% CI, 1.9 to 3.9), respectively. Both risk category (P <.0005) and compliance with guidelines (P <.0005) were independent significant predictors of survival. CONCLUSION: Treatment according to consensus recommendations is associated with improved survival of women with breast cancer in the community. Promoting the adoption of guidelines for treatment is an effective strategy for disease control.     

Treatment of mild hyperhomocysteinemia in renal transplant recipients versus hemodialysis patients

BACKGROUND: Mild hyperhomocysteinemia is common among maintenance hemodialysis (HD) patients and renal transplant recipients (RTR) and may contribute to the excess incidence of arteriosclerotic outcomes experienced by both patient groups. Relative to their RTR counterparts, the hyperhomocysteinemia of HD patients seems to be considerably more refractory to treatment with high-dose folic acid (FA)-based B-vitamin supplementation regimens, although controlled comparison data are lacking. METHODS: We compared the relative responsiveness of (n=10) RTR and (n=39) HD patients with equivalent baseline total homocysteine (tHcy) levels (i.e., RTR range=14.2-23.6 micromol/L; HD range=14.4-24.9 micromol/L) to 12 weeks of tHcy-lowering treatment. The RTR received 2.4 mg/day of FA, 50.0 mg/day of vitamin B6, and 0.4 mg/day of vitamin B12, while the HD patients received 15 mg/day of FA or an equimolar amount (17 mg/day) of the reduced folate, L-5-methyltetrahydrofolate, in addition to 50.0 mg/day of vitamin B6, and 1.0 mg/day of vitamin B12. RESULTS: The mean percent (%) reductions (+/-95% confidence interval) in tHcy were: RTR=28.1% (16.2-40.0%); HD=12.1% (6.6-17.7%), P=0.027 for comparison of between-groups differences by analysis of covariance adjusted for baseline tHcy levels. Moreover, (50.0%) of 10 of the RTR versus only (5.1%) of 39 of the HD patients had final on-treatment tHcy levels <12 micromol/L; P=0.002 for comparison of between-groups differences by Fisher's exact test. CONCLUSION: Relative to RTR with comparable baseline tHcy levels, the mild hyperhomocysteinemia of maintenance HD patients is much more refractory to tHcy-lowering B-vitamin treatment regimens featuring supraphysiological amounts of FA or the reduced folate, L-5-methyltetrahydrofolate. Accordingly, RTR are a preferable target population for controlled clinical trials testing the hypothesis that tHcy-lowering B-vitamin intervention may reduce arteriosclerotic cardiovascular disease event rates in patients with chronic renal disease.     

A comparison in cosmetic outcome between per-operative interstitial breast implants and delayed interstitial breast implants after external beam radiotherapy.

BACKGROUND AND PURPOSE: Interstitial implants for brachytherapy boost in the breast conserving therapy of breast cancer can be performed in two ways; implants during the tumor excision (per-operative implants) or after the external beam therapy (delayed interstitial implants). Differences in cosmetic outcome were investigated. PATIENTS AND METHODS: Cosmetic results in 47 patients having a per-operative implant were compared to 123 patients having a delayed interstitial implant in a matched case-control study. Cosmesis was scored on a four-point-scale varying from 0 (excellent) to 3 (poor). RESULTS: After mean follow-up of 63 months, three observers found no difference in cosmetic outcome between the two groups after adjustment for variables found to be related with cosmesis (difference in mean score 0.50, P=0.26). Implant volume at 100% isodose was not found to differ (P=0.084) between the per-operative group (mean 102 cm3, S.D. 34 cm3) and the delayed group (mean 93 cm3, S.D. 29 cm3). CONCLUSIONS: Performing per-operative implants has not led to smaller implants. The method of performing brachytherapy does not result in marked differences in cosmetic outcome.     

How to optimize physicians' communication skills in cancer care: results of a randomized study assessing the usefulness of posttraining consolidation workshops.

PURPOSE: Although there is wide recognition of the usefulness of improving physicians' communication skills, no studies have yet assessed the efficacy of post-training consolidation workshops. This study aims to assess the efficacy of six 3-hour consolidation workshops conducted after a 2.5-day basic training program. METHODS: Physicians, after attending the basic training program, were randomly assigned to consolidation workshops or to a waiting list. Training efficacy was assessed through simulated and actual patient interviews that were audiotaped at baseline and after consolidation workshops for the consolidation-workshop group, and approximately 5 months after the end of basic training for the waiting-list group. Communication skills were assessed according to the Cancer Research Campaign Workshop Evaluation Manual. Patients' perceptions of communication skills improvement were assessed using a 14-item questionnaire. RESULTS: Sixty-three physicians completed the training program. Communication skills improved significantly more in the consolidation-workshop group compared with the waiting-list group. In simulated interviews, group-by-time repeated measures analysis of variance showed a significant increase in open and open directive questions (P =.014) and utterances alerting patients to reality (P =.049), as well as a significant decrease in premature reassurance (P =.042). In actual patient interviews, results revealed a significant increase in acknowledgements (P =.022) and empathic statements (P =.009), in educated guesses (P =.041), and in negotiations (P =.008). Patients interacting with physicians who benefited from consolidation workshops reported higher scores concerning their physicians' understanding of their disease (P =.004). CONCLUSION: Consolidation workshops further improve a communication skills training program's efficacy and facilitate the transfer of acquired skills to clinical practice.     

CT-based delineation of lymph node levels and related CTVs in the node-negative neck: DAHANCA, EORTC, GORTEC, NCIC,RTOG consensus guidelines.

BACKGROUND AND PURPOSE: The appropriate application of 3-D CRT and IMRT for HNSCC requires a standardization of the procedures for the delineation of the target volumes. Over the past few years, two proposals--the so-called Brussels guidelines from Grégoire et al., and the so-called Rotterdam guidelines from Nowak et al.--emerged from the literature for the delineation of the neck node levels. Detailed examination of these proposals however revealed some important discrepancies. MATERIALS AND METHODS: Within this framework, the Brussels and Rotterdam groups decided to review their guidelines and derive a common set of recommendations for delineation of neck node levels. This proposal was then discussed with representatives of major cooperative groups in Europe (DAHANCA, EORTC, GORTEC) and in North America (NCIC, RTOG), which, after some additional refinements, have endorsed them. The objective of the present article is to present the consensus guidelines for the delineation of the node levels in the node-negative neck. RESULTS AND CONCLUSIONS: First a short discussion of the discrepancies between the previous Brussels and the Rotterdam guidelines is presented. The general philosophy of the consensus guidelines and the methodology used to resolve the various discrepancies are then described. The consensus proposal is then presented and representative CTVs that are consistent with these guidelines are illustrated on CT sections. Last, the limitations of the consensus guidelines are discussed and some concerns about the direct applications of these guidelines to the node-positive neck and the post-operative neck are described.     

Plasma vitamin B-12 concentrations relate to intake source in the Framingham Offspring study

BACKGROUND: Low vitamin B-12 status is prevalent among the elderly, but few studies have examined the association between vitamin B-12 status and intake. OBJECTIVE: We hypothesized that vitamin B-12 concentrations vary according to intake source. DESIGN: Plasma concentrations and dietary intakes were assessed cross-sectionally for 2999 subjects in the Framingham Offspring Study. The prevalence of vitamin B-12 concentrations <148, 185, and 258 pmol/L was examined by age group (26-49, 50-64, and 65-83 y), supplement use, and the following food intake sources: fortified breakfast cereal, dairy products, and meat. RESULTS: Thirty-nine percent of subjects had plasma vitamin B-12 concentrations <258 pmol/L, 17% had concentrations <185 pmol/L, and 9% had concentrations <148 pmol/L, with little difference between age groups. Supplement users were significantly less likely than non-supplement-users to have concentrations <185 pmol/L (8% compared with 20%, respectively). Among non-supplement-users, there were significant differences between those who consumed fortified cereal >4 times/wk (12%) and those who consumed no fortified cereal (23%) and between those in the highest and those in the lowest tertile of dairy intake (13% compared with 24%, respectively), but no significant differences by meat tertile. Regression of plasma vitamin B-12 on log of intake, by source, yielded significant slopes for each contributor adjusted for the others. For the total group, b = 40.6 for vitamin B-12 from vitamin supplements. Among non-supplement-users, b = 56.4 for dairy products, 35.2 for cereal, and 16.7 for meat. Only the meat slope differed significantly from the others. CONCLUSIONS: In contrast with previous reports, plasma vitamin B-12 concentrations were associated with vitamin B-12 intake. Use of supplements, fortified cereal, and milk appears to protect against lower concentrations. Further research is needed to investigate possible differences in bioavailability.     

Intraplacental Choriocarcinoma Associated with Viable Pregnancy: Pathologic Features and Implications for the Mother and Infant

Choriocarcinoma arising in the placenta, or intraplacental choriocarcinoma, has seldom been reported, particularly in the absence of maternal metastases. Reluctance to diagnose choriocarcinoma in the presence of chorionic villi can delay diagnosis; however, timely diagnosis of choriocarcinoma is prognostically important, both for the mother and infant. We report the clinicopathologic findings in five mothers and infants in whom choriocarcinoma was identified in the placenta. None of the mothers had a history of gestational trophoblastic disease in previous pregnancies. Three placentas were similar with a single small lesion grossly suggesting a small infarct; microscopically these consisted of infarcted areas surrounded by choriocarcinoma. These three mothers were unusual in that none had metastatic choriocarcinoma; two were treated with chemotherapy and remained disease-free; the third was lost to follow-up shortly following delivery. The remaining two mothers had known pulmonary metastases at time of delivery. One of these latter two placentas contained a large marginal lesion microscopically identified as choriocarcinoma. The fifth placenta had rare microscopic foci of choriocarcinoma, and sheets of necrotic choriocarcinoma were identified in “blood clot” submitted with the placenta. In four of the five cases the choriocarcinoma appeared to be arising from otherwise normal chorionic villi, and in no case was there invasion of the villous stroma. All of the infants survived, and none had evidence of choriocarcinoma. These cases support the concept that choriocarcinoma associated with otherwise normal pregnancy arises in the placenta and may be more common than reported. Received August 11, 1997; accepted December 8, 1997.     

Preclinical in vivo antitumor activity of vinflunine, a novel fluorinated Vinca alkaloid

Vinflunine, or 20′,20′-difluoro-3′,4′-dihydrovino‐relbine, is a novel Vinca alkaloid obtained by hemisynthesis using superacidic chemistry. The most impressive structural modification of this vinorelbine derivative was the selective introduction of two fluorine atoms at the 20′ position, a part of the molecule previously inaccessible by classic chemistry. The antitumor activity of vinflunine was evaluated against a range of transplantable murine and human tumors. Vinflunine exhibited marked activity against murine P388 leukemia grafted i.v. when given i.p. in single or multiple doses according to various schedules or in single i.v. or p.o. doses. Increases in life span achieved with vinflunine, as assessed by T/C ratios, ranged from 200% to 457% and proved markedly superior to those of 129–186% obtained with the other Vinca alkaloids tested. Against s.c.-implanted B16 melanoma, multiple i.p. administration of vinflunine proved active in terms of both survival prolongation and tumor growth inhibition, with optimal T/C values and relative areas under the tumor growth curves (rAUC) being 24% and 36%, respectively. The extent of this activity was superior to that noted for vinorelbine under the same experimental conditions. Growth inhibition of human tumor xenografts LX-1 (lung) and MX-1 (breast) was also observed following four weekly i.p. injections of vinflunine as reflected by optimal T/C values of 23% and 26%, respectively, and significant differences in the rAUCs noted for treated versus control animals. It was also noticeable that vinflunine induced considerably more prolonged inhibitory effects on tumor growth than did vinorelbine. These results demonstrate that vinflunine is well tolerated and is definitively active against a range of experimental animal tumor models. Vinflunine activity has been documented in terms of both survival prolongation and tumor growth inhibition, with definite superiority over vinorelbine being shown in each tumor model evaluated. Received: 13 July 1997 / Accepted: 21 October 1997