Electrophysiological characterisation of the human N-type Ca2+ channel III: pH-dependent inhibition by a synthetic macrocyclic polyamine

The effects of a novel synthetic macrocyclic polyamine (LY310315) were investigated on recombinant human N-type Ca2+ channels stabley expressed in HEK293 cells. LY310315 proved to be a potent and reversible N-type Ca2+ channel antagonist. Inhibition by this compound was dose-dependent with an IC50 of approximately 0.4 microM at pH 7.35. LY310315 blocked very rapidly at all concentrations tested. Upon washout, recovery of the Ca2+ current developed with a time constant of approximately 30 s. Use-dependence in the development of block indicated that voltage-dependent transitions in the channel protein were required to permit significant inhibition. Application of > 100 times the IC50 dose of LY310315 to the interior of the cell produced no detectable Ca2+ current inhibition. LY310315 had no effects on the kinetics of channel activation or deactivation but did slightly slow the rate of macroscopic inactivation observed during a 300 ms test depolarisation. In the presence of LY310315 the activation curve was significantly shallower. This resulted in a shift in the activation midpoint voltage to a more depolarised levels. LY310315-induced inhibition of human N-type channels was strongly dependent on the extracellular pH, with increased potency seen upon extracellular acidification. Although most effective against N-type Ca2+ channels, LY310315 was also found to inhibit both P-type and L-type Ca2+ channels. LY310315 proved to be a weak blocker of Na+ currents, but produced approximately 50% of the K+ currents of AtT20 cells at a concentration of 0.5 microM.

Experimental pragmatics and what is said: a response to Gibbs and Moise

Gibbs and Moise [Gibbs, R., Moise, J., 1997. Pragmatics in understanding what is said. Cognition 62, 51-74], present experimental results which, they claim, show that people recognize a distinction between what is said and what is implicated. They also claim that these results provide support for theories of utterance interpretation (such as RELEVANCE Theory) which recognize that pragmatic processes are involved not only in understanding what is implicated but also in working out what is said (the 'explicature'). We attempted to replicate some of these experiments and also adapted them. Our results fail to confirm Gibbs and Moise's claims. Most significantly, they show that, under certain conditions, subjects select implicatures when asked to select the paraphrase that best reflects what a speaker has said. We suggest that our results can be explained within the framework of RELEVANCE Theory (Sperber, D., Wilson, D., 1986.

RELEVANCE

Communication and Cognition. Blackwell, Oxford) if we assume that subjects select the paraphrase that comes closest to achieving the same set of communicated contextual effects as the original utterance. When an utterance gives rise to a single strong implicature, subjects tend to select this as the paraphrase that best reflects what is said; in other cases (for example in Gibbs and Moise's stimuli) subjects tend to select the explicature.

Corneal opacities in Gaucher disease

PURPOSE

To describe the corneal findings in a variant of Gaucher disease.

METHODS

Case report. In an 18-year-old man, ophthalmic and general clinical evaluation, and enzymatic and molecular genetics studies were performed.

RESULTS

Diffuse, well-defined, small, linear, or dotlike corneal opacities were observed through, out the posterior two thirds of the corneal stroma in both eyes. The patient had calcific valvular heart disease. Enzymatic and ultrastructural studies were consistent with Gaucher disease. Analysis of the glucocerebrosidase gene disclosed homozygosity for a D409H mutation.

CONCLUSION

Corneal opacities are a distinguishing ocular feature of the variant of Gaucher disease associated with the D409H mutation and with calcific cardiac disease.

Sulphur-containing amino acids are agonists for group 1 metabotropic receptors expressed in clonal RGT cell lines

Comparison of the pharmacological effects of a range of sulphur-containing amino acids on human mGluR1alpha and mGluR5a has been undertaken. cDNAs of each mGluR were transfected into a Syrian hamster tumour cell line AV12-664 that was previously transfected with the rat glutamate-aspartate transporter protein (GLAST). The L-isomers of cysteine sulphinic acid (CSA), homocysteine sulphinic acid (HCSA), cysteic acid (CA) and serine-O-sulphate (SOS) stimulated PI hydrolysis in human mGluR1alpha and mGluR5a cells with full agonist effects. D-CSA, the only active D-isomer, was a partial agonist for mGluR5a whereas L-sulphocysteine (S-CYS) showed weak agonist-like effects at high concentrations on both mGluR1alpha and mGluR5a. L-Homocysteic acid was inactive on both mGluR1alpha and mGluR5a cells. Treatment of mGluR cultures with glutamate pyruvate transaminase did not alter the potencies of the S-amino acids on PI hydrolysis responses. Inhibitor constants (Ki) obtained for L-HCSA, L-CSA, L-CA and L-SOS in [3H]glutamate receptor binding studies with mGluR1alpha cells indicated that L-HCSA, L-CSA, L-CA and L-SOS can bind specifically to mGluR1 with L-HCSA showing the highest affinity. These results confirm that certain endogenously produced S-amino acids may interact directly with group 1 mGluRs.

Overexpression of p53 protein does not predict local-regional control or survival in patients with early-stage squamous cell carcinoma of the glottic larynx treated with radiotherapy

PURPOSE

Nonfunctional or mutated p53 protein (m-p53) is found in a myriad of solid tumors in humans. m-p53 is believed to confer radioresistance through inhibition of radiation-induced apoptosis. This study was carried out to determine if the overexpression of p53 in squamous cell carcinomas (SCC) of the glottic larynx treated with radiation therapy alone carried a poorer prognosis than normal wild-type p53 (w-p53) and could, therefore, be used as a marker of radioresistance in glottic SCC.

METHODS & MATERIALS

Eighty-six patients with early-stage glottic SCC (64 T1N0, 25 T2N0 by TMN stage) treated with contemporary radiotherapy techniques to doses of 50-70 Gy were analyzed. Aberrant p53 protein was detected by immunohistochemical (IHC) staining on archival tissue samples containing original tumor specimens. Analysis of prognostic factors and treatment outcome to expression of p53 was performed. All patients were carefully selected to have comparable sites of disease, histology, early-stage disease, and treatment delivered, thus increasing the power of this study by controlling for other independent factors affecting outcome.

RESULTS

Sixty percent of patients demonstrated overexpression of p53 in tissue samples. Accumulation of p53 was not predictive of tumor grade, stage, or smoking status prior to diagnosis. p53 status was not predictive of treatment outcome parameters including local-regional failure rate and disease-free survival rate. Factors significantly affecting treatment outcome were stage and dose of radiotherapy in T2 patients (50 Gy vs. > 62 Gy).

CONCLUSION

m-p53 protein detected by IHC staining was not predictive as a prognostic factor for clinical outcome following radiation therapy for early-stage glottic SCC. This is in general agreement with other recently published studies of laryngeal carcinoma patients treated with radiation or surgery. At the present time, p53 status should not be used as a marker for prognosis and clinical outcome in laryngeal SCC.

Evidence for non-synchronous rotation of Europa. Galileo Imaging Team

Non-synchronous rotation of Europa was predicted on theoretical grounds, by considering the orbitally averaged torque exerted by Jupiter on the satellite's tidal bulges. If Europa's orbit were circular, or the satellite were comprised of a frictionless fluid without tidal dissipation, this torque would average to zero. However, Europa has a small forced eccentricity e approximately 0.01 , generated by its dynamical interaction with Io and Ganymede, which should cause the equilibrium spin rate of the satellite to be slightly faster than synchronous. Recent gravity data suggest that there may be a permanent asymmetry in Europa's interior mass distribution which is large enough to offset the tidal torque; hence, if non-synchronous rotation is observed, the surface is probably decoupled from the interior by a subsurface layer of liquid or ductile ice. Non-synchronous rotation was invoked to explain Europa's global system of lineaments and an equatorial region of rifting seen in Voyager images. Here we report an analysis of the orientation and distribution of these surface features, based on initial observations made by the Galileo spacecraft. We find evidence that Europa spins faster than the synchronous rate (or did so in the past), consistent with the possibility of a global subsurface ocean.

NEAR's flyby of 253 mathilde: images of a C asteroid

On 27 June 1997, the Near Earth Asteroid Rendezvous (NEAR) spacecraft flew within 1212 kilometers of asteroid 253 Mathilde. Mathilde is an irregular, heavily cratered body measuring 66 kilometers by 48 kilometers by 46 kilometers. The asteroid's surface is dark (estimated albedo between 0.035 and 0.050) and similar in color to some CM carbonaceous chondrites. No albedo or color variations were detected. The volume derived from the images and the mass from Doppler tracking of the spacecraft yield a mean density of 1.3 +/- 0.2 grams per cubic centimeter, about half that of CM chondrites, indicating a porous interior structure.

Effect of recombinant interleukin-6 and thrombopoietin on isolated guinea pig bone marrow megakaryocyte protein phosphorylation and proplatelet formation

Guinea pig bone marrow megakaryocytes were isolated and cultured on collagen gels to promote proplatelet formation. In control cultures 15.6% of the cells formed proplatelets. Both IL6 and TPO stimulated dose dependent increases in the percent of proplatelet forming cells up to 26.7% at 100ng/mal IL6 and 26.8% at 100 ng/ml TPO. IL1 and IL3 had no effect on proplatelet formation. IL3 in combination with IL6 and TPO blocked the increase in proplatelet formation observed with IL6 or TPO alone. IL3 was also found to stimulate thymidine incorporation in megakaryocytes. The role of phosphorylation in proplatelet formation was studied using certain inhibitors. The tyrosine kinase inhibitor genestien had no effect on proplatelet formation at concentrations up to 100 microg/ml. The phosphatase inhibitors calyculin A and okadaic acid both inhibited proplatelet formation. Studies on protein phosphorylation revealed that IL6, but not TPO, stimulated phosphorylation of JAK1, JAK2 and MAP kinase. TPO did stimulate tyrosine phosphorylation of Tyk-2. Although IBMX stimulated proplatelet formation, it inhibited phosphorylation of JAK1 and MAP kinase. Adhesion of megakaryocytes to collagen gel also inhibited phosphorylation of JAK1 and JAK2, while MAP kinase phosphorylation was unaffected. These data show that IL6 and TPO stimulate megakaryocyte proplatelet formation. In addition, although these cytokines increase phosphorylation of signal transduction proteins in the JAK/STAT pathway, it appears that a different signal transduction pathway regulated by a combination of phosphatase activity and cAMP levels, leads to proplatelet formation.

Fronto-facio-nasal dysplasia

Fronto-facio-nasal dysplasia is a rare cause of facial clefts. The syndrome is characterized by paramedian facial clefts which involve the nose and palpebral fissures resulting in defects of the alae nasi and blepharophimosis, lagophthalmos, and S-shaped palpebral fissures. In addition affected children have ocular malformations such as epibulbar dermoids and colobomata of the iris or optic disk and may have a posterior encephalocele; these features distinguish this condition from fronto-nasal dysplasia and early amnion rupture sequence. We describe a child with unilateral features. Unilateral craniofacial clefts are usually assumed to have a low recurrence risk. However, fronto-facio-nasal dysplasia is an autosomal recessive condition and must be considered in any child with paramedian facial clefts.

Practice guideline for examination of the placenta: developed by the Placental Pathology Practice Guideline Development Task Force of the College of American Pathologists

The Placental Pathology Practice Guideline Development Task Force, a multidisciplinary group, has prepared this guideline to assist those involved with placental examination. It provides recommendations related to indications and methods for placental examination as well as sample worksheets. An algorithm for the handling of placentas summarizes the recommendations of the guideline. A summary of specific findings of placental examination together with their pathogenesis and clinical associations is also provided. Recommendations related to reporting with sample reporting formats are included. The guideline is intended as an educational tool, and its use should be guided by the individual circumstances and care setting of specific cases.

Gamete intrafallopian transfer. Does smoking play a role?

OBJECTIVE

To investigate the effects of active and passive cigarette smoking on the outcome of gamete intrafallopian transfer (GIFT).

STUDY DESIGN

A retrospective analysis of 98 patients who had laparoscopic GIFT was performed. Data were retrieved concerning age, diagnosis, amount of human menopausal gonadotropins (hMG) used for controlled ovarian hyperstimulation (COH), and number of oocytes retrieved and transferred. A detailed smoking history, if any, of patients and household members was obtained from chart review and an additional telephone survey. Pregnancy rates and outcome in active and passive smokers were compared to those of non-smokers.

RESULTS

No difference was observed among active smokers (n = 19), passive smokers (n = 13) or nonsmokers (n = 66) regarding diagnosis, age percentage of mature oocytes retrieved or number of oocytes transferred during GIFT. However, active, but nor passive, smokers consumed a higher amount of hMG for COH as compared to nonsmokers. More important, pregnancy and live birth rates for active smokers (15.8% and 10.5%, respectively) were significantly lower than those for passive smokers (46.2% and 23.1%) and nonsmokers (45.5% and 33.3%). No difference, however, was noted between the latter two groups.

CONCLUSION

Our results show that active, but not passive, smoking has a negative impact on GIFT pregnancy rates and outcomes. It is important to counsel patients against cigarette smoking prior to GIFT, but whether smoking cessation will improve the outcome needs further study.

Assignment of human elongation factor 1alpha genes: EEF1A maps to chromosome 6q14 and EEF1A2 to 20q13.3

The human elongation factor 1alpha gene family consists of at least 2 actively transcribed genes, EEF1A and EEF1A2, and more than 18 homologous loci. EEF1A2 is expressed in a tissue-specific manner, whereas EEF1A is expressed ubiquitously, and both of them can function in translation. An EEF1A cDNA probe has previously been shown to cross-hybridize with several human chromosomes, but the location of the functional gene has not been established. We have mapped the functional EEF1A gene to 6q14 by combined fluorescence in situ hybridization (FISH) and PCR analysis of a somatic cell hybrid panel and mapped EEF1A2 to 20q13.3 by FISH. In addition, the 11 strongest cross-hybridizing loci (EEF1AL2-EEF1AL13) were mapped by FISH to 12p12, 9q34, 7p15-p21, 19q13, 3q26-q27, 7q33-q35, 1p13-p22, 2q12-q14, 5p12-q11, 1q31-q32, and Xq21.

An assessment of the comparative utility of functional and molecular level analyses in the investigation of patients with thrombophilia

Aim-To determine the relation of the low anticoagulant response phenotype with the Factor V Q506 (Leiden) mutation in a cohort of patients with thrombophilia.Methods-Fifty four patients with either a personal or family history of deep vein thrombosis were investigated both for their anticoagulant response by the activated protein C resistance test (APCR) and their genetic status in respect of the Leiden mutation by means of a PCR-RFLP method.Results-Low APCR ratios do not necessarily predict possession of the Leiden mutation. Conversely, normal ratios do not exclude the mutation. Of 14 individuals with low APCR ratios, the Leiden mutation was absent in five. Of the remainder, three were heterozygous and six homozygous. Of nine heterozygote individuals, only three had low APCR ratios. All patients homozygous for the defect had low APCR ratios.Conclusions-These results lend further weight to the hypothesis that the APC resistant phenotype results from more than one genetic defect and indicate the value of combined functional and molecular investigations in all patients with thrombophilia.

The Suess-Urey mission (return of solar matter to Earth)

The Suess-Urey (S-U) mission has been proposed as a NASA Discovery mission to return samples of matter from the Sun to the Earth for isotopic and chemical analyses in terrestrial laboratories to provide a major improvement in our knowledge of the average chemical and isotopic composition of the solar system. The S-U spacecraft and sample return capsule will be placed in a halo orbit around the L1 Sun-Earth libration point for two years to collect solar wind ions which implant into large passive collectors made of ultra-pure materials. Constant Spacecraft-Sun-Earth geometries enable simple spin stabilized attitude control, simple passive thermal control, and a fixed medium gain antenna. Low data requirements and the safety of a Sun-pointed spinner, result in extremely low mission operations costs.

Strategic planning and the health care supervisor

This article explores strategic planning from the perspective of the health care supervisor. It analyzes the strategic environment of organizations, the planning process, how to evaluate the strategic plan, and the implementation phase. A strategic planning model is offered as well as a view of the future of strategic planning. The article articulates that strategic planning should emphasize flexibility. The plan needs to be custom designed for the particular organization. Strategic planning is a primary vehicle for health care supervisors to use work teams to further develop organizational effectiveness. Finally, strategic planning is linked to both research and systems theory.

[Brain metastasis. Palliative treatment with radiosurgery]

This is a retrospective review of 52 patients with metastatic brain disease who underwent stereotactic radiosurgery at McGill University in Montreal. The radiosurgical treatment was performed with the dynamic rotation technique in which there is continuous and simultaneous movement of treatment couch and machine gantry of a 10 MV linac. All patients were treated with a single isocenter and a median dose of 1800 cGy was delivered. In 88% of the cases radiosurgery was given after failure from whole brain conventional irradiation. All 52 cases were assessed with brain CT post radiosurgery. The median follow up time was 6 months (range 1-37 months) and the response rate (partial or complete) was 64%. Only 4 patients (7%) developed late complications related to the treatment. These findings are similar to the literature. Stereotactic radiosurgery is a well tolerated, effective and minimally invasive treatment technique which has a high response rate in selected patients with small, well delineated metastatic brain lesion. Its definitive value as a single therapy or combined with whole brain conventional radiotherapy is being studied in prospective and randomized trials.

Induction of rodent hepatic drug-metabolizing enzyme activities by the novel anticonvulsant remacemide hydrochloride

Remacemide hydrochloride [FPL 12924AA; 2-amino-N-(1-methyl-1,2-diphenylethyl) acetamide hydrochloride] is being evaluated as a novel neuroprotective treatment for epilepsy and stroke. Preliminary safety evaluation studies in the rat have shown that repeated doses of the compound produce histological and biochemical changes consistent with hepatic enzyme induction. To examine this further, the levels and activities of the major drug metabolizing cytochrome P450 (CYP) subfamilies (CPY1, CYP2, and CYP3) were monitored in microsomal samples from male Sprague-Dawley rats dosed by gavage with FPL 12924AA (250 mg base.kg-1.day-1 for 28 days) or an equivalent volume of vehicle (controls). The interpretation of the findings was aided by comparison with the effects of phenobarbitone (75 mg.kg-1.day-1 ip for 4 days) and beta-naphthoflavone (a single intraperitoneal dose at 80 mg.kg-1.day-1). No significant changes in total hepatic P450 levels (1.44 +/- 0.40 nmol.mg-1 vs. 1.31 +/- 0.19 nmol.mg-1 in controls) or ethoxyresorufin O-deethylase activity (a CYP1A induction probe) were observed after remacemide treatment. The pattern of induction produced by remacemide was very similar to that observed with phenobarbitone. The nonspecific CYP-dependent reaction ethoxycoumarin O-deethylation was induced approximately 2-fold. The specific CYP2B markers pentoxyresorufin O-depentylase and 16 beta-hydroxytestosterone production were both increased markedly by FPL 12924AA (approximately 100- and 20-fold, respectively). 2 beta- and 6 beta-Hydroxytestosterone production were also elevated, indicating the induction of CYP3A1/2. Similar effects on isoform-selective P450-dependent activities were observed in male and female mice treated with remacemide as part of a dose-ranging study.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of outpatient cardiac and pulmonary rehabilitation patients

PURPOSE

Although cardiac and pulmonary rehabilitation are frequently considered together, differences in the two populations have not been evaluated adequately.

METHODS

This study compared patients who were referred to outpatient cardiac and pulmonary rehabilitation over a 1-year period at the authors' institution. Fifty-five cardiac rehabilitation patients (CR) and 47 pulmonary rehabilitation patients (PR) were studied with respect to age, gender, weight, smoking history, functional status, employment status, numbers and types of diagnoses and medications, and number of recent hospitalizations and hospital days.

RESULTS

Cardiac rehabilitation patients were approximately 7 years younger, smoked less, were somewhat heavier, had a markedly better functional status, and were more likely employed than their counterparts in pulmonary rehabilitation. In addition, this group had fewer diagnoses and used fewer medications than PR patients. The number of hospitalizations and hospital days in the year preceding rehabilitation, however, were greater in CR patients than in PR patients.

CONCLUSIONS

CR patients and PR patients are quite distinct with respect to demographics, functional status, comorbidity, and hospital resource consumption.