Polychlorinated biphenyl serum concentrations, lifestyle and time-to-pregnancy

BACKGROUND

Consumption of fish contaminated with polychlorinated biphenyls (PCBs) and prenatal PCB serum concentrations have been associated with a longer time-to-pregnancy (TTP). However, the relationship between preconception serum PCBs concentrations and TTP has not been previously studied.

METHODS

Eighty-three women (contributing 442 menstrual cycles) planning pregnancies completed daily diaries regarding menstruation, intercourse, home pregnancy test results, and reported use of alcohol and cigarettes. TTP denoted the number of observed menstrual cycles required for pregnancy. Preconception blood specimens underwent toxicologic analysis for 76 PCB congeners via gas chromatography with electron capture; serum lipids were quantified with enzymatic methods. A priori, PCB congeners were summed into a total and three groupings-estrogenic, anti-estrogenic and other-and entered into discrete analogs of Cox models with time-varying covariates to estimate fecundability odds ratios (FOR) and corresponding 95% confidence intervals (CIs).

RESULTS

Estrogenic and anti-estrogenic PCB concentrations (ng/g serum) conferred reduced FORs in fully adjusted models (0.32; 95% CI 0.03, 3.90 and 0.01: 95% CI < 0.00, 1.99, respectively). Reduced FORs (0.96) were observed for alcohol consumption standardized to a 28-day menstrual cycle in the same adjusted model (FOR = 0.96; 95% CI 0.93, 1.00).

CONCLUSIONS

These data suggest that environmental exposures including those amenable to change, such as alcohol consumption, may impact female fecundity. The findings are sensitive to model specification and PCB groupings, underscoring the need to further assess the impact of chemical mixtures on sensitive reproductive outcomes, such as TTP, especially in the context of lifestyle factors which are amenable to change, thereby improving reproductive health.

Intravesical pressure and the TUR syndrome

Intravesical pressure was measured continuously during 35 transurethral prostate resections using a fine suprapubic catheter. Absorption of irrigating fluid was detected by tagging it with ethanol and sampling the expired breath using an alcohol meter. Higher mean (SD) intravesical pressure was demonstrated in those patients who absorbed irrigating fluid (19.1 (7.7) mmHg) than in those who did not (12.4 (6.5) mmHg; p = 0.00004). Higher peak pressures were also demonstrated among absorbing patients. Traditional risk factors for fluid absorption, such as operator experience and resectate mass, were found to correlate with pressure exposure over time. Exposure to supranormal bladder pressure over time is the final common path for all causes of absorption. Vesical pressure monitoring may be a valuable feedback tool during difficult resections or operator training.

WITHDRAWN: Surgery for cervical radiculomyelopathy

BACKGROUND

Cervical spondylosis causes pain and disability by compressing the spinal cord or roots. Surgery to relieve the compression may reduce the pain and disability, but is associated with a small but definite risk. We sought to assess the balance of risk and benefit from surgery.

OBJECTIVES

To determine whether: 1) surgical treatment of cervical radiculopathy or myelopathy is associated with improved outcome, compared with conservative management and 2) timing of surgery (immediate or delayed upon persistence/progression of relevant symptoms and signs) has an impact on outcome.

SEARCH STRATEGY

We searched Medline (between 1966 and 1998), Embase (between 1980 and 1998) and the Cochrane Controlled Trials Register. Authors of the identified randomised controlled trials were contacted to detect any additional published or unpublished data.

SELECTION CRITERIA

All unconfounded truly or quasi-randomised controlled trials allocating patients with cervical radiculopathy or myelopathy to 1) "best medical management" or "decompressive surgery (with or without some form of fusion) plus best medical management" 2) "early decompressive surgery" or "delayed decompressive surgery".

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion, assessed trial quality and extracted the data.

MAIN RESULTS

Two trials involving a total of 130 patients were included. One trial with 81 patients compared surgical decompression with either physiotherapy or cervical collar immobilization in patients with cervical radiculopathy. The short-term effects of surgery, in terms of pain, weakness or sensory loss were superior, however, at one year no significant differences between groups were present. One trial with 49 patients compared the effects of surgery with those of conservative treatment in patients with mild functional deficit associated with cervical myelopathy. No significant differences were observed between groups, up to two years following treatment.

AUTHORS' CONCLUSIONS

The available small randomised trials do not provide reliable evidence on the effects of surgery for cervical spondylotic radiculopathy or myelopathy. It is not clear whether the short-term risks of surgery are offset by any long-term benefits.

How we do it: patient participation in cochlear implant selection

. Involving patients and parents in the choice of their cochlear implant encourages an active role in the process and facilitates 'bonding' and 'ownership' of the device. . The most frequent reasons given by patients for selecting a device included cochlear implant comfort and appearance. . We describe the Implant Programme based at the Royal National Throat, Nose and Ear Hospital, London, and also examine patient satisfaction with the scheme.

Bridging the gap: can a link nurse initiative influence palliative care in an acute hospital?

With 90% of people needing some inpatient hospital care in the final year of life, it is evident that the provision and awareness of palliative care, and education surrounding this, are widely needed. This study aims to evaluate a palliative care link nurse initiative (PCLN) in an NHS acute hospital, identifying key factors affecting link nurses' ability to influence palliative care practice. This qualitative study used semi-structured interviews and a focus group to show the anticipated and actual influence of link nurses on practice. Findings suggest that link nurses had increased knowledge and skills in palliative care due to education provided. Link nurses were seen to have an influence on the presence and quality of palliative care practice in hospital wards. Factors that could help link nurses to have greater influence are reported, as are difficulties in providing care and accessing training.

Delving of sandy surfaced soils reduces frost damage in wheat crops

Delving is a farming practice involving the mixing of a deep clayey subsoil layer with a sandy topsoil. One of the many effects of this practice is to reduce soil albedo and increase water-holding capacity of the topsoil, thus increasing the potential for storage and release of heat and potential attenuation of the effects of radiative frost. At Keith, a frost-prone location of South Australia, we investigated the effect of management practices with putative capacity to reduce frost damage, with emphasis on delving. Three field experiments were established on Brown Sodosols with a water-repellent sand topsoil. In relation to crops in untreated control soil, delving increased wheat yield from 1.9 to 3.1 t/ha in 2003, and from 0.5 to 1.5 t/ha in 2004. This large delving effect contrasted with the minor effects of other treatments including soil rolling, sowing rate, row spacing, and cultivar mixture. Lack of significant interactions between treatments indicated a robust response to delving across a range of management practices. Topsoil and canopy-height minimum temperatures were consistently higher in the delved treatment. The average difference in canopy-height minimum temperature between delved and control treatments was 0.3–0.4°C, with a maximum of 1.6°C in 2003 and 1.2°C in 2004. A single, robust relationship between yield and frost damage fitted the data pooled across treatments and seasons. This, together with the temperature differential between treatments, and significant relationships between minimum canopy-height temperature around flowering and frost damage supported the conclusion that a substantial part of the yield gain attributable to delving was related to reduced frost damage.

High-power source of THz radiation based on orientation-patterned GaAs pumped by a fiber laser

We demonstrate a new source of frequency-tunable THz wave packets based on parametric down-conversion process in orientation-patterned GaAs (OP-GaAs) that produces muW-level THz average powers at the repetition rate of 100 MHz. The OP-GaAs crystal is pumped by a compact all-fiber femtosecond laser operating at the wavelength of 2 mum. Such combination of fiber laser and OP-GaAs technologies promises a practical source of THz radiation which should be suitable for many applications including imaging and spectroscopy.

Radiation Treatment Decreases Bone Cancer Pain, Osteolysis and Tumor Size

Radiotherapy is the cornerstone of palliative treatment for primary bone cancer in animals and metastatic bone cancer in humans. However, the mechanism(s) responsible for pain relief after irradiation is unknown. To identify the mechanism through which radiation treatment decreases bone cancer pain, the effect of radiation on mice with painful bone cancer was studied. Analysis of the effects of a 20-Gy treatment on localized sites of painful bone cancers was performed through assessments of animal behavior, radiographs and histological analysis. The findings indicated that radiation treatment reduced bone pain and supported reduced cancer burden and reduced osteolysis as mechanisms through which radiation reduces bone cancer pain.

Morbidity data collection in general practice: experience in the South Eastern Health Board 1998-1999

A joint project between general practitioners and the South Eastern Health Board resulted in the establishment of a network of computerised practices collecting morbidity data in 1998 - 1999. Five practices established age sex registers for public and private patients. The International Classification of Primary Care 2 (ICPC-2) was used to define inclusion criteria for a range of illnesses relevant to primary care and public health. Problems arose in validating and extracting data in three practices. Disease prevalence for 17 illnesses was established for two practices only. The project clearly established the problems associated with morbidity data collection in general practice which include absence of a national patient registration system, absence of a national electronic messaging standard, difficulties extracting data from practice software systems and the need for a high level of dedicated staff and resources to implement such a project.

Effect of tetrandrine on cellular electrophysiology and calcium uptake of myocardium in guinea pigs and dogs

OBJECTIVE

To study the effects of tetrandrine, a Chinese herbal medicine, on the action potential (AP), contraction as well as sarcoplasmic reticulum (SR) calcium uptake of myocardium in guinea-pigs and dogs.

METHODS

Changes in AP, dV/dt, peak tension (PT) and dT/dt of myocardial cells were studied using the technique of glass electrode. Changes of the calcium uptake rate by sarcoplasmic reticulum and release of inorganic phosphate from sarcoplasmic reticulum were assessed with biochemical techniques.

RESULTS

Tetrandrine exerts a concentration-dependent and frequency-dependent negative inotropic effect and shortens action potential duration. Tetrandrine depresses both dT(E)/dt and dT(L)/dt as well as the tension of myocardium, and reduces dV/dt and amplitude only in the slow action potential, thus implying that tetrandrine blocks the slow calcium channel. In addition, compared with thapsigargin, a specific inhibitor of Ca(2+)-ATPase on SR, tetrandrine more apparently suppresses the contraction of the myocardium.

CONCLUSIONS

Tetrandrine is a wide-range calcium antagonist of plant origin. Not only it blocks the voltage-operated calcium channels as other authors reported, but also may play an important role in affecting the function of Ca(2+)-ATPase and calcium release channels on SR. From this study, we also suggest that the calcium channel appears to be more critical than SR for the contraction of myocardium.

Speech processing strategy preferences among 55 European CLARION cochlear implant users

This multicentre study investigates the preference and performance of a group of 55 adult CLARION cochlear implant users with the choice of simultaneous analogue stimulation (SAS) and continuous interleaved sampler (CIS) strategies during the first 3 months of implant use. Subjects were programmed with both strategies and instructed to use each of the two strategies in daily life to ascertain preference. Subjects were tested in both strategies with open-set sentence materials, auditory alone, at 2, 6 and 12 weeks after the initial programming session. Questionnaires were completed with preference ratings being recorded for the two strategies: 25% of subjects preferred SAS and 75% CIS. Subjects performed better in their strategy of choice. Preferences were set very early on in the process and did not change. Factors influencing preference are discussed. Offering the choice of fundamentally different strategies improves both individual and group performance.

Gemcitabine and vinorelbine in patients with advanced lung cancer: preclinical studies and report of a phase I trial

PURPOSE

This study was designed to assess the efficacy of gemcitabine plus vinorelbine using the mouse Lewis lung carcinoma model and to translate this regimen to a phase I clinical study of these two agents in patients with advanced lung cancer.

MATERIALS AND METHODS

Using the mouse Lewis lung cancer model, employing growth delay and isobologram analysis, we demonstrated that gemcitabine, in combination with vinorelbine, produced additive activity with little increased toxicity over a wide range of doses. At the highest dose level studied, antagonism was observed. Based on these results, we initiated a phase IGemcitabine and vinorelbine in patients with advanced lung cancer: preclinical studies and report of a phase I trial study of this combination at the Dana Farber Cancer Institute (DFCI) in patients with untreated or once pretreated non-small-cell lung cancer (NSCLC) or once pretreated small-cell lung cancer (SCLC). Vinorelbine (given in an intravenous bolus) and gemcitabine (given in a 30-min infusion) were initially administered to patients at a dose of 15 mg/m2 and 500 mg/m2, respectively, on days 1, 8, and 15 of a 28-day cycle. Seven dose levels were subsequently explored over the course of the study. There was no intrapatient dose escalation.

RESULTS

From November 1996 to March 1998, 40 patients were enrolled: 32 had NSCLC, 5 had SCLC and 3 had mixed disease (both SCLC and NSCLC). The patients were evenly divided by gender, the median age was 58 years (range 38 to 73 years), and the median ECOG performance status was 1 (range 0 to 2). All patients had normal renal and hepatic function and none had previously received gemcitabine or vinorelbine. Toxic reactions included mild to moderate fatigue, nausea, constipation, and, most significantly, neutropenia and thrombocytopenia. Phlebitis was a major problem when central venous lines were not used with 15% grade 1/2 events. The day-15 dose was held in 43% of patients at the expanded dose. No true maximum tolerated dose was reached after completion of seven dose levels. Dose level 4 (22.5 mg/m2 vinorelbine and 1,000 mg/m2 gemcitabine) was chosen for expansion and future study due to the potential increased ability of patients to receive the full doses on time.

CONCLUSIONS

We conclude that this drug combination and dosage are feasible and have potential as either a front- or second-line chemotherapeutic regimen for advanced lung cancer, and phase II/III trials should be performed. However, hematologic toxicities, as found in this study, could probably be reduced with treatment on days 1 and 8 every 21 days, and current literature would suggest this to be the preferred schedule.

Calmodulin Signals Capacitation and Triggers the Agonist-Induced Acrosome Reaction in Mouse Spermatozoa

Capacitated acrosome-intact spermatozoa interact with specific sugar residues on neoglycoproteins (ngps) or solubilized zona pellucida (ZP), the egg's extracellular glycocalyx, prior to the initiation of a signal transduction cascade that results in the fenestration and fusion of the sperm plasma membrane and the outer acrosomal membrane at multiple sites and exocytosis of acrosomal contents (i.e., induction of the acrosome reaction (AR)). The AR releases acrosomal contents at the site of sperm-zona binding and is thought to be a prerequisite event that allows spermatozoa to penetrate the ZP and fertilize the egg. Since Ca(2+)/calmodulin (CaM) plays a significant role in several cell signaling pathways and membrane fusion events, we have used a pharmacological approach to examine the role of CaM, a calcium-binding protein, in sperm capacitation and agonist-induced AR. Inclusion of CaM antagonists (calmodulin binding domain, calmidazolium, compound 48/80, ophiobolin A, W5, W7, and W13), either in in vitro capacitation medium or after sperm capacitation blocked the npg-/ZP-induced AR. Purified CaM largely reversed the AR blocking effects of antagonists during capacitation. Our results demonstrate that CaM plays an important role in priming (i.e., capacitation) of mouse spermatozoa as well as in the agonist-induced AR. These data allow us to propose that CaM regulates these events by modulating sperm membrane component(s).

A phase II trial of the cyclin-dependent kinase inhibitor flavopiridol in patients with previously untreated stage IV non-small cell lung cancer

PURPOSE

Flavopiridol is a potent cyclin-dependent kinase inhibitor with preclinical activity against non-small cell lung cancer (NSCLC), inhibiting tumor growth in vitro and in vivo by cytostatic and cytotoxic mechanisms. A Phase II trial was conducted to determine the activity and toxicity of flavopiridol in untreated patients with metastatic NSCLC.

EXPERIMENTAL DESIGN

A total of 20 patients were treated with a 72-h continuous infusion of flavopiridol every 14 days at a dose of 50 mg/m(2)/day and a concentration of 0.1-0.2 mg/ml. Dose escalation to 60 mg/m(2)/day was permitted if no significant toxicity occurred. Response was initially assessed after every two infusions; patients treated longer than 8 weeks were then assessed after every four infusions. Plasma levels of flavopiridol were measured daily during the first two infusions to determine steady-state concentrations.

RESULTS

This study was designed to evaluate a total of 45 patients in two stages. However, because no objective responses were seen in the first 20 patients, the early-stopping rule was invoked, and patient accrual was halted. In four patients who received eight infusions, progression was documented at 15, 20, 40, and 65 weeks, respectively. The most common toxicities included grade 1 or 2 diarrhea in 11 patients, asthenia in 10 patients, and venous thromboses in 7 patients. The mean +/- SD steady-state concentration of drug during the first infusion was 200 +/- 89.9 nM, sufficient for cytostatic effects in in vitro models.

CONCLUSIONS

At the current doses and schedule, flavopiridol does not have cytotoxic activity in NSCLC, although protracted periods of disease stability were observed with an acceptable degree of toxicity.

Differential sensitivity of expressed L-type calcium channels and muscarinic M(1) receptors to volatile anesthetics in Xenopus oocytes

Since volatile anesthetics inhibited high voltage-gated calcium channels and G-protein-coupled M(1) muscarinic signaling, their effects upon M(1) receptor-induced modulation of L-type (alpha1C) calcium channel was investigated. Voltage-clamped Ba(2+) currents (I(Ba)) were measured in Xenopus oocytes coexpressed with L-type channels and M(1) muscarinic receptors. M(1) receptor agonist, acetyl-beta-methylcholine (MCh) inhibited the peak and late components of I(Ba) in a dose-dependent manner. Analysis of I(Ba) after the treatment with MCh or volatile anesthetics revealed that the inactivating component, its time constant, and the noninactivating current were all decreased by these agents. MCh-induced inhibition followed a second messenger pathway that included G-proteins, phospholipase C, inositol-1,4,5-trisphosphate, and intracellular calcium [Ca(2+)](i). Although halothane or isoflurane inhibited I(Ba,) their effect was not mediated through these intracellular second messengers. By using volatile anesthetics and MCh sequentially, and in various combinations, the susceptibility of L-type currents and their modulation by M(1) receptors to volatile anesthetics were investigated. When MCh and volatile anesthetics were administered together simultaneously, a pronounced inhibition that was approximately equal to the sum of their individual effects was seen. Halothane or isoflurane further inhibited the I(Ba) when either volatile anesthetic was administered following the inhibition produced by prior administration of MCh. However, when MCh was administered following either volatile anesthetic, its effect was significantly reduced. Thus, whereas volatile anesthetics appear to directly inhibit L-type channels, they also interfere with channel modulation by G-protein-coupled receptors, which may have functional implications for both neuronal and cardiovascular tissues.