Intracranial Displacement Measurements Within Targeted Anatomical Regions of a Postmortem Human Surrogate Brain Subjected to Impact

The dynamic response of the human brain subjected to impulsive loading conditions is of fundamental importance to the understanding of traumatic brain injuries. Due to the complexity of such measurements, the existing experimental datasets available to researchers are sparse. However, these measurements are used extensively in the validation of complex finite element models used in the design of protective equipment and the development of injury mitigation strategies. The primary objective of this study was to develop a comprehensive methodology to measure displacement in specific anatomical regions of the brain. A state-of-the-art high-speed cineradiography system was used to capture brain motion in post-mortem human surrogate specimens at a rate of 7500 fps. This paper describes the methodology used to capture these data and presents measurements from these tests. Two-dimensional displacement fields are presented and analyzed based on anatomical regions of the brain. These data demonstrated a multi-modal displacement response in several regions of the brain. The full response of the brain consisted of an elastic superposition of a series of bulk rotations of the brain about its centre of gravity. The displacement field could be linked directly to specific anatomical regions. The methods presented mark an improvement in temporal and spatial resolution of data collection, which has implications for our developing understanding of brain trauma.

Adsorption and binding dynamics of graphene-supported phospholipid membranes using the QCM-D technique

We report on the adsorption dynamics of phospholipid membranes on graphene-coated substrates using the quartz crystal microbalance with dissipation monitoring (QCM-D) technique. We compare the lipid vesicle interaction and membrane formation on gold and silicon dioxide QCM crystal surfaces with their graphene oxide (GO) and reduced (r)GO coated counterparts, and report on the different lipid structures obtained. We establish graphene derivative coatings as support surfaces with tuneable hydrophobicity for the formation of controllable lipid structures. One structure of interest formed is lipid monolayer membranes which were formed on rGO, which are otherwise challenging to produce. We also demonstrate and monitor biotin-avidin binding on such a membrane, which will then serve as a platform for a wide range of biosensing applications. The QCM-D technique could be extended to both fundamental studies and applications of other covalent and non-covalent interactions in 2-dimensional materials.

Weight maintenance over 12 months after weight loss resulting from participation in a 12-week randomised controlled trial comparing all meal provision to self-directed diet in overweight adults

BACKGROUND

The results of weight maintenance after initial weight loss are reported infrequently, although, when they have been reported, the outcomes are generally poor and weight regain is common.

METHODS

After an initial 12-week randomised intervention comparing all meal provision against a self-directed energy restriction, participants re-consented to participate in a follow-on study. Participants were given the option to choose to continue with the same dietary intervention (either all meal provision (provided free of charge) or self-directed diet) or change to the other diet for a further 12 weeks. Participants were followed up at 4-weekly intervals during both intervention periods (a total of 24 weeks), with a final follow up at 12 months.

RESULTS

Eighty-five out of 86 individuals who completed the original 12-week randomised phase chose to continue on to the follow-up study. No significant differences in further weight loss between groups (P = 0.138) [mean (SEM): -3.4% (1.1%) for all meal provision only; -3.4% (0.6%) self-directed then all meal provision; -1.1% (1.2%) all meal provision then self-directed] were seen after a further 12 weeks. Meal provision for a total of 24 weeks resulted in 67% of individuals losing at least 10% body weight. The groups switching from self-directed dieting to meal provision (or vice versa) were the only groups to have a lower mean weight at 12 months than at the start of the follow-on study.

CONCLUSIONS

Structured support for 24 weeks followed by 28 weeks of self-care can result in weight maintenance, with initial weight loss maintained at 12 months from enrolling on a 12-week weight loss intervention, with a 12-week follow-on period.

Weight loss in a UK commercial all meal provision study: a randomised controlled trial

BACKGROUND

Effective approaches are needed to address the increasing prevalence of overweight and obesity. The present study investigated whether all meal provision was a more effective and acceptable method for weight loss than a self-directed diet.

METHODS

This randomised controlled trial recruited 112 men and women with a body mass index in the range 27-35 kg m(-2), who had no comorbidities, from the local area of Hull. Participants were randomised to receive either meal provision or follow a self-directed diet for a 12-week period that resulted in an estimated 2928 kJ day(-1) (700 kcal day(-1)) deficit. A dietitian supervised both dietary interventions.

RESULTS

At 12 weeks [mean (SEM)], percentage weight loss in the meal provision group was 6.6% (0.5%) compared to 4.3% (0.6%) for those on the self-directed diet. In terms of clinically relevant weight loss, 61% of participants lost 5% or more of their body weight with meal provision compared to 22% on the self-directed diet (P < 0.001). Weight loss was associated with wellbeing in both groups. Attrition was less apparent with 7% of those participants receiving meal provision withdrawing from the study compared to 41% of those following the self-directed diet (P < 0.001).

CONCLUSIONS

Meal provision was a more effective and accepted method for weight loss over a 12-week period compared to a self-directed diet. This may in part represent the difference between being given the meal provision food free of charge. However, longer-term maintenance studies need to be undertaken to ascertain their effects on the maintenance of weight loss.

Influence of mass transfer limitations on determination of the half saturation constant for hydrogen uptake in a mixed-culture CH(4)-producing enrichment

There is strong evidence in the literature supporting the existence of significant mass transfer limitations on the kinetics of exogenous H(2) consumption by methanogens. The half saturation constant for H (2) uptake by a mixed-culture, CH(4) producing enrichment was measured using an experimental protocol that avoided internal mass transfer limitations. The value obtained was two orders of magnitude smaller than any other previously reported. A mathematical model for acetogenic syntrophic associations was developed to check the capacity of H(2) as electron transporter between syntrophic partners. It was found that H(2) diffusion could account for the rate of transport of electrons between the syntrophic microorganisms and that formate is not a necessary intermediate. The possibility that formate may be an intermediate in this system was not ruled out. A Monod-type kinetic equation was modified to include the observed H(2) threshold effect. This modified equation was used to predict the CH(4)-production rate in a batch-fed digester. The results show that the external and internal H(2) pools are kinetically coupled.

Effective treatment of an elderly patient with Gaucher's disease and Parkinsonism: A case report of 24 months’ oral substrate reduction therapy with miglustat

We report here the results of 24 months' treatment with oral miglustat of a patient with mild-to-moderate Gaucher's disease (GD) and Parkinsonism. The patient's progressive Parkinsonian tremor, in addition to restricted vascular access, necessitated switching treatment for GD from intravenously infused enzyme replacement therapy (ERT) that had been administered for the previous 7 years. With control of haematological parameters and markers of GD activity improved or maintained and no notable adverse effects, miglustat treatment proved an effective and well-tolerated therapeutic alternative to ERT. Oral miglustat should be considered for the treatment of patients with type I GD and concurrent movement disorders who are unsuitable for ERT.

Intravenous enzyme replacement therapy: better in home or hospital?

This article evaluates satisfaction with enzyme replacement therapy (ERT) at home and at hospital in adult patients with Fabry and Gaucher diseases. A questionnaire was developed and sent to 34 patients with Fabry disease who were receiving ERT with agalsidase alfa (Replagal) and to 49 patients with type I Gaucher disease who were receiving ERT with glucocerebrosidase (Cerezyme). Of the 45 returned questionnaires, 20 were from patients with Fabry disease and 25 from patients with Gaucher disease. Hospital treatment visits were reported as stressful by 18 patients (40%), whereas only 4 (9%) patients reported that home therapy was stressful. Both groups of patients adjusted well to receiving home-based therapy. Nearly all of the patients with Fabry disease (19 patients, 95%) and Gaucher disease (21 patients, 84%) preferred home-based therapy. Treatment in the home was reported as more comfortable, less stressful, more effective and had less impact on family life. Only 4 (9%) patients chose to continue receiving infusions in hospital. The majority of patients with Fabry disease and Gaucher disease found home-based therapy to be more convenient and less stressful than hospital-based therapy.

Developing the public health practitioner workforce in England: lessons from theory and practice

FOCUS

The paper focuses on public health practitioners who collectively represent one of three key workforce groups identified by England's Chief Medical Officer as critical to the successful delivery of national public health policy priorities.

QUESTION

We report on two areas of work which attempt to address the following two-part question: in developing the public health practitioner workforce in England, what is needed, and how do we do it?

APPROACH

First, we describe a five-component conceptual framework for developing the public health workforce which is grounded in data derived from a national Open Space event hosted by the University of the West of England in March 2005. The five components are (i) strategic support and oversight; (ii) national technical and professional support; (iii) national career building; (iv) local organisational development, and (v) sub-regional skills development. Key elements of each component are described in the paper. Second, we describe in some detail a new multidisciplinary skills development programme which illustrates one of the framework components (sub-regional skills development). The programme, established in January 2005, is aimed at three key groups of public health practitioners: health visitors (specialist community public health nurse), school nurses and environmental health officers. Its main features and some initial evaluation findings are presented.

CONCLUSIONS

To be effective, activities aimed at supporting the development of the public health practitioner workforce should, where possible, aim to be congruent with core public health principles of self-determination and collective responsibility. We also conclude that leadership and vision at a national level, combined with local implementation of evidence-based training programme such as the one described could help to achieve much greater and more rapid progress in skilling up the existing public health practitioner workforce than has been possible up to now. But we note that this requires sustained investment, robust sector-wide delivery frameworks, and a group of committed local public health champions.

A comparison between the theory and reality of full-scale step-feed nutrient removal systems

Capacity enhancement and volume reduction benefits of step-feeding fully aerobic bioreactors has been well documented. Application of step-feed technology to biological nutrient removal (BNR) systems, particularly those removing nitrogen alone or both nitrogen and phosphorus, is relatively new to the industry. In recent years, a number of full-scale step-feed facilities have been brought into service. This paper reviews nine full-scale step-feed biological nutrient removal systems--both nitrogen removal alone, and nitrogen and phosphorus removal. The objective is to compare the theoretical benefits of such systems with their actual operation. The predicted benefits of reduced bioreactor volume or increased process capacity, reduced energy usage, more robust nitrification performance, and the flexibility to tune (or de-tune) nitrification efficiency were verified in full-scale systems. Equations are also presented that may be used in the prediction of step-feed benefits. There are two primary drivers for considering a step-feed biological reactor system: 1. Reduced bioreactor volume for a defined capacity or performance or increased process capacity given a fixed bioreactor volume. 2. More robust nitrification performance. Full-scale operation of these step-feed nutrient removal systems provides a real world basis for the claimed benefits of step-feed operation. These systems have uniformly shown additional capacity. A number of them have also exhibited more robust performance, especially during storms. Where possible, side-by-side comparisons of full-scale step-feed systems with non-step-feed systems have exhibited greater process reliability and flexibility.

Primary B-cell lymphoma of the skin: the Sheffield Lymphoma Group Experience (1984-2003)

The clinical presentation, treatment and outcome were retrospectively evaluated in a series of 66 patients with primary B-cell lymphoma of the skin, referred to the Sheffield lymphoma group (SLG) between 1984 and 2003. This is the largest series reported from the UK. The lymphoma database was searched and clinical records were reviewed. Absence of any detectable extracutaneous lesion and the expression of B-cell restricted antigens by neoplastic cells were the essential criteria for selection of cases. The cohort included 37 (56%) males and 29 (44%) females with a mean age of 59 years. The most commonly involved site was the trunk and the disorder typically showed non-aggressive clinical behaviour; the majority of the patients presented with stage I (82%) disease with a tendency to remain localised to a limited area of the skin. Follicular lymphoma was the most common histologic subtype (35%), the next most frequent was the diffuse large cell lymphoma (32%) whereas marginal zone lymphoma constituted 15%. The majority (47%) of patients were treated with radiotherapy for localised disease whereas chemotherapy was given in 20% of patients, with single agent chlorambucil being most frequently used. Surgical excision as the sole modality of treatment was adequate in 33%. Disease-free survival (DFS) was 91% at 1 year, 82% at 2 years and 60% at 5 years. DFS was significantly lower with older age (>45 years), leg lesions, generalised and multiple lesions, and for those treated with chemotherapy. The survival at 5 and 10 years was 80%. The histologic grade, leg involvement and the number of lesions were the most significant variables affecting overall survival. Only 7 patients died of lymphoma. In conclusion, primary cutaneous B-cell lymphoma represents a specific entity concerning clinical behaviour, response to treatment, and overall prognosis.

Hearing improvement in patients with Fabry disease treated with agalsidase alfa

AIM

To describe the nature and prevalence of hearing loss in Fabry disease, and its response to enzyme replacement therapy (ERT) with agalsidase alfa.

METHODS

Fifteen male patients with Fabry disease were enrolled in a randomized, double-blind study and received placebo (n = 8) or ERT (n = 7) with agalsidase alfa for 6 months. This was followed by an open-label extension of 36 months thus far. Alongside this trial, an additional eight men and two women have so far received open-label ERT for between 6 and 30 months. Pure-tone audiometry, impedance audiometry and otoacoustic emission testing were performed at 0 (baseline), 6, 18, 30 and 42 months.

RESULTS

Nine patients (36%) had bilateral and ten (40%) had unilateral high-frequency sensorineural hearing loss (SNHL). Three (12%) had unilateral middle ear effusions with conductive losses persisting beyond 6 months. Only five patients (20%) had normal hearing. The high-frequency SNHL deteriorated over the first 6 months in both placebo and active treatment groups by a median 6.3 dB (p < 0.0001, Wilcoxon matched-pairs). This hearing loss subsequently improved above baseline by 1.5 dB at 18 months (p = 0.07), by 5.0 dB at 30 months (p = 0.006) and by 4.0 dB at 42 months (p = 0.01).

CONCLUSION

Significant hearing loss, usually high-frequency SNHL, is a common manifestation of Fabry disease in adults. Alpha-galactosidase A replacement therapy with agalsidase alfa appears to reverse the hearing deterioration in these patients. This improvement, however, is gradual, suggesting the need for long-term ERT.

Outcomes following unilateral uterine artery embolisation

Uterine artery embolisation has been described as successful only when both arteries are embolised. However, results in patients with one congenitally absent or previously ligated artery are unknown. Women suffering from symptomatic uterine myomata were treated at a university teaching hospital, a community hospital and an outpatient surgery centre. Retrospective review of patient response to embolisation was assessed by chart review and questionnaire. Uterine and dominant fibroid size response was assessed by comparing pre- and post-embolisation ultrasound examinations. This study analysed three patient groups within the general population: those who underwent unilateral embolisation because of technical failure, those who ultimately underwent bilateral embolisation after initial technical failure and those who underwent unilateral embolisation because of an absent uterine artery. 12 patients underwent unilateral embolisation, 4 of whom underwent this procedure because of an absent uterine artery. Three of these four patients had a congenitally absent uterine artery arising from the internal iliac artery and all three experienced successful outcomes. The fourth patient had a previously ligated internal iliac artery and her symptoms worsened after the procedure. Eight patients had unilateral embolisation due to technical failure. Five of these patients underwent a subsequent procedure during which the contralateral uterine artery was embolised. Four of these five patients had successful outcomes and one was lost to follow-up. Another of the eight patients suffered an arterial injury leading to technical failure, and was lost to follow-up. Of the two remaining patients with unilateral technical failure, only one had a successful outcome. This study concluded that patients who undergo unilateral embolisation for technical reasons should be offered a second embolisation procedure shortly after the initial procedure. Patients with a congenitally absent uterine artery may respond with similar success to those who underwent bilateral embolisation. In contrast, the patient with a previously ligated internal iliac artery failed. The numbers in this study are too small for statistical analysis and subsequent studies should be performed to confirm these findings.

In vitro polymerization and copolymerization of 3-hydroxypropionyl-CoA with the PHB synthase from Ralstonia eutropha

The poly(3-hydroxybutyrate) (PHB) synthase of Ralstonia eutropha, which was produced by a recombinant strain of Escherichia coli and purified in one step with a methyl-HIC column to a purity of more than 90%, was used to polymerize 3-hydroxypropionyl-CoA (3HPCoA) and to copolymerize 3HPCoA with 3-hydroxybutyryl-CoA (3HBCoA). A Km of 189 microM and a kcat of 10 s-1 were determined for the activity of the enzyme in the polymerization reaction of 3HPCoA based on the assumption that the dimer form of PHB synthase was the active form. Free coenzyme A was found to be a very effective competitive inhibitor for the polymerization of 3HPCoA with a Ki of 85 microM. The maximum degree of conversion of 3HPCoA to polymer was less than 40%. In the simultaneous copolymerization reactions of these two monomers, both the turnover number for the copolymerization reaction and the maximum degree of conversion of 3HPCoA and 3HBCoA to copolymers increased with an increase in the amount of 3HBCoA in the monomer mixture. However, the maximum conversion of 3HPCoA to copolymer was always less than 35%, regardless of the ratio of 3HPCoA to 3HBCoA. Block copolymers were obtained by the sequential copolymerization of the two monomers and these copolymers had a much narrower molecular weight distribution than those obtained by the simultaneous copolymerization for the same molar ratio of 3HPCoA to 3HBCoA.

Kinetic and mechanistic characterization of the polyhydroxybutyrate synthase from Ralstonia eutropha

Purified Ralstonia eutropha polyhydroxybutyrate (PHB) synthase from recombinant cells can exist as monomer and dimer. The polymerization reaction catalyzed by this enzyme displays a lag phase, which causes difficulties for kinetic and mechanistic characterization of the enzymatic polymerization reaction. In this study, we developed a method to eliminate the lag phase of PHB synthase by physical means, i.e., adding multihydroxyl compounds to the enzyme solution. This method allows us to recognize the nature of the lag phase as a physical rather than a chemical process. With such lag-phase-free-enzyme, the kinetic properties of the enzyme were investigated. The results indicate that 3-hydroxybutyryl-CoA (3HBCoA) is the optimal substrate for the enzyme. A slower catalytic rate and lower binding ability account for a lower reactivity of 3-hydroxyvaleryl-CoA (3HVCoA) compared to that of 3HBCoA. The change of hydroxyl group from the beta to the gamma position causes dramatic decreases in the binding ability of 4-hydroxybutyryl-CoA (4HBCoA). By using a dilution strategy and size exclusion chromatographic technique, the active form of the enzyme was identified to be the dimeric form. The number of catalytic sites in the dimeric form of the enzyme was examined by comparing the molecular weight of polyhydroxybutyrate as a function of substrate-to-enzyme ratio. The results suggest that the dimeric enzyme has only one catalytic site. A revised model of polymerization reaction catalyzed by R. eutropha PHB synthase is described.

Enzymatic hydrolysis of oligomeric models of poly-3-hydroxybutyrate

The mechanism of the enzymatic degradation of poly([R]-3-hydroxybutyrate) (PHB) was investigated by using well-defined model substrates, including both linear and cyclic [R]-3-hydroxybutyrate (3HB) and [R]-3-hydroxyvalerate (3HV) oligomers, with two different PHB depolymerases. The linear and cyclic oligomers containing from 2 to 10 repeating units were hydrolyzed in solutions of the depolymerase isolated from Aspergillus fumigatus and Alcaligenes faecalis, and the rates of hydrolysis and types of products formed were characterized. Both of the depolymerases catalyzed the hydrolysis of the cyclic oligomers (macrolides) which contained more than three 3HB and 3HV repeating units. The degradation reactions of the linear and cyclic 3HB oligomers with the A. fumigatus depolymerase gave similar ratios of monomer-to-dimer products, but PHB itself formed mostly monomer on hydrolysis, indicating that the enzymatic hydrolysis reactions occurred by different mechanisms for these different types of substrates. The results of this study conclusively show that at least the endo mode of polymer hydrolysis occurs with the two enzymes studied, while the A. fumigatus depolymerase was found to utilize both endo and exo modes of hydrolysis to efficiently degrade PHB and 3HB oligomers.

Pregnancy following uterine fibroid embolization

OBJECTIVE

This paper seeks to evaluate the ability to deliver term pregnancies following uterine fibroid embolization, and to identify impediments to pregnancy in the embolization procedure.

STUDY DESIGN

Four physicians performed embolization procedures at various facilities. Patients were asked if fertility was an issue prior to embolization. We measured follicle-stimulating hormone levels before and after embolization. Clinical follow-up, six months following embolization was obtained by interview. Patients were questioned regarding attempts to conceive, menstrual history, and subsequent pregnancy.

MAIN OUTCOME MEASURES

Complications were calculated upon the entire patient population, whether or not fertility was identified as a goal. Fertility risks from embolization were identified. We measured radiation exposure in a random consecutive group of 50 women undergoing embolization. All patients who conceived were asked the details of the pregnancy.

RESULTS

Four hundred women underwent uterine fibroid embolization between 1996 and 1999. One hundred and thirty nine patients stated a desire for fertility after embolization. Of these, 52 were <40 years old. Seventeen pregnancies have been reported in 14 women. Five spontaneous abortions were observed. Ten women have had normal term deliveries and two women are currently pregnant. No perfusion problems, either during the pregnancy or labor, were reported. The average radiation dosage calculated for 50 women undergoing embolization was 14 rads. Four women under 45 years old suffered premature menopause (10/1000). Two women underwent hysterectomy as a complication of embolization (5/1000).

CONCLUSION

The risks of infertility following embolization, premature menopause, and hysterectomy are small, as is the radiation exposure during embolization. These risks compare favorably with those associated with myomectomy. Fertility rates appear similar to patients undergoing myomectomy. No problems, either during pregnancy or delivery, have been observed after embolization. The course of pregnancy and delivery was normal after embolization with no maternal or fetal complications reported. These findings confirm results from other centers. Desire for future pregnancy is not a contraindication to fibroid embolization.

Comparative study of the relationship between monomer structure and reactivity for two polyhydroxyalkanoate synthases

Using organically synthesized hydroxyalkanoate coenzyme A thioesters, the activities of two short-chain polyhydroxalkanoate (PHA) synthases were investigated--Ralstonia eutropha PHA synthase (a type I PHA synthase) and Ectothiorhodospira shaposhnikovii PHA synthase (a type III synthase). The results indicate that the two synthases have similar activities towards most of the monomers tested. 3-Hydroxybutyryl CoA was found to be the most efficient substrate for both synthases. Changes in the side-chain length of the monomers affect monomer reactivity, with shortening of the side-chain length having the more severe effect. Hydrophobicity in the side chain appears to play an important role in the catalytic reaction. The configuration and the position of the hydroxyl group also affect the reactivity of a monomer. Monomers with the [S] configuration can not be recognized by either synthase. Moving the hydroxyl group from the beta carbon to the alpha carbon has a much more severe effect on the reactivity of the monomer than moving the hydroxyl group to the gamma carbon. The results demonstrate that the in vitro system can be used to prepare entirely novel polymers that may not be obtainable from living cells because of metabolic restrictions.

Bleeding complications associated with the use of rt-PA versus r-PA for peripheral arterial and venous thromboembolic occlusions

This article analyzes the early experience with alteplase (rt-PA) and reteplase (r-PA) to identify noteworthy differences in bleeding and to determine correlations with dosage, concomitant anticoagulation, and duration of infusion. A retrospective review of the medical records was unavailable for the initial 82 patients who were treated with either rt-PA (44) or r-PA (38) for peripheral arterial or venous occlusions after urokinase therapy. Successful recanalization was achieved in 31/44 (70%) of the patients treated with rt-PA and in 34/38 (89%) of the patients treated with r-PA. Significant bleeding was documented in 20/44 (45%) of the rt-PA-treated patients (including 14 transfusions) versus 3/38 (8%) of the r-PA-treated patients (3 transfusions). Concomitant anticoagulation with either preceding warfarin (international normalized ratio > 1.1) or a bolus of heparin at the outset of the infusion was associated with significant bleeding in 13/17 (76%) of the rt-PA-treated patients (including 9 transfusions) versus 0/17 in the r-PA-treated patients. No significant correlation between either mean dose or total dose and bleeding was shown for either drug. Early experience indicates that r-PA is at least as effective as rt-PA for the thrombolysis of peripheral arterial and venous occlusions. It also appears that r-PA is less likely than rt-PA to be associated with significant bleeding during such infusions, especially if the patient is concomitantly anticoagulated.

Characterization, seasonal occurrence, and diel fluctuation of poly(hydroxyalkanoate) in photosynthetic microbial mats

In situ poly(hydroxyalkanoate) (PHA) levels and repeating-unit compositions were examined in stratified photosynthetic microbial mats from Great Sippewissett Salt Marsh, Mass., and Ebro Delta, Spain. Unlike what has been observed in pure cultures of phototrophic bacteria, the prevalence of hydroxyvalerate (HV) repeating units relative to hydroxybutyrate (HB) repeating units was striking. In the cyanobacteria-dominated green material of Sippewissett mats, the mole percent ratio of repeating units was generally 1HB:1HV. In the purple sulfur bacteria-dominated pink material the relationship was typically 1HB:2HV. In Sippewissett mats, PHA contributed about 0.5 to 1% of the organic carbon in the green layer and up to 6% in the pink layer. In Ebro Delta mats, PHA of approximately 1HB:2HV-repeating-unit distribution contributed about 2% of the organic carbon of the composite photosynthetic layers (the green and pink layers were not separated). Great Sippewissett Salt Marsh mats were utilized for more extensive investigation of seasonal, diel, and exogenous carbon effects. When the total PHA content was normalized to organic carbon, there was little seasonal variation in PHA levels. However, routine daily variation was evident at all sites and seasons. In every case, PHA levels increased during the night and decreased during the day. This phenomenon was conspicuous in the pink layer, where PHA levels doubled overnight. The daytime declines could be inhibited by artificial shading. Addition of exogenous acetate, lactate, and propionate induced two- to fivefold increases in the total PHA levels when applied in the daylight but had no effect when applied at night. The distinct diel pattern of in situ PHA accumulation at night appears to be related, in some phototrophs, to routine dark energy metabolism and is not influenced by the availability of organic nutrients.

Down-regulation of TGF-beta1 production restores immunogenicity in prostate cancer cells

The objective of this study is to determine if a non-immunogenic Dunning's rat prostate cancer cell line, MATLyLu, can become immunogenic by reducing the endogenous production of TGF-beta1. An expression construct containing a DNA sequence in an antisense orientation to TGF-beta1 (TGF-beta1 antisense) was stably transfected into MATLyLu cells. Following transfection, cellular content of TGF-beta1 reduced from 70 to 10 pg per 2x10(4) cells and the rate of in vitro 3H-thymidine incorporation increased 3-5-fold. After subcutaneous injection of tumour cells into syngeneic male hosts (Copenhagen rats), the tumour incidence was 100% (15/15) for the wild type MATLyLu cells and cells transfected with the control construct, but only 43% (9/21, P< or =0.05) for cells transfected with TGF-beta1 antisense. However, when cells were injected into immunodeficient hosts (athymic nude rats), the incidence of tumour development was 100% (10/10) for both the wild type MATLyLu cells and cells transfected with the control construct and 90% (9/10) for cells transfected with TGF-beta1 antisense. These observations support the concept that MATLyLu cells are immunogenic, when the endogenous production of TGF-beta1 is down-regulated.

Community development through faculty practice in a rural nurse-managed clinic

This article describes a community-academic partnership that led to the development of a nurse-managed clinic (NMC) in 1996 in a rural Indiana area designated by the state as a medically underserved area (MUA) and a health professional shortage area (HPSA). Application of the community development model in faculty practice is described in relation to the clinic. The project is ongoing; lessons learned to date, which have implications for others involved in faculty practice, are described.

Methane production and release from two New England peatlands

The rate of methane production and release to the atmosphere was determined for two New England peat bogs. Methane production rates from peat sediments, which were measured down to depths of 150 cm, ranged from 1 to 15 micromoles per liter per hour. The highest rates of methane production occurred at depths of 60-100 cm. Methane release from these same peats was quantified from various habitats on the bog using gas collection chambers. The chambers enclose a two-liter volume and cover an area of 0.02 m2. Methane accumulation in the chambers was measured for periods of up to 18 days. Methane release was related to pH and habitat zone. The lowest rates of methane release were from those portions of the bogs that had pH values below 5.0. Peak methane release occurred during or immediately after ice melt in both wetlands with release rates as high as 34 mmoles/m2/d. The overall estimate of yearly release of methane from these bog systems is 2,900 and 14,900 moles per year for Arcadia and Hawley Bogs respectively. Both of these bogs have pH environments close to the lowest limit for methanogenesis, and small differences in pH values can have a large impact on both the rate of methane production and the rate of methane release to the atmosphere.

A personalised approach to cardiac rehabilitation

Patients' beliefs about their myocardial infarction will affect their physical and emotional recovery. An individualised, behavioural approach to rehabilitation aims to treat the patient as an adult learner who participates fully in negotiating priorities for rehabilitation. Initiating rehabilitation advice in the very early stages post-AMI requires the use of specific nursing interventions.

Transforming growth factor-beta type II receptor confers tumor suppressor activity in murine renal carcinoma (Renca) cells

OBJECTIVES

To demonstrate that the introduction of the transforming growth factor-beta (TGF-beta) type II receptor (TbetaR-II) decreases tumorigenicity in an aggressive murine renal carcinoma line, Renca. These cells do not express TbetaR-II. Because the presence of TbetaR-II in benign epithelial cells is ubiquitous, the ability to restore tumor suppressor activity in the Renca cell line with its introduction would elucidate the role of TbetaR-II as a tumor suppressor gene.

METHODS

Renca cells were stably transfected with a retrovirus-mediated TbetaR-II expression vector. In vitro sensitivity to growth inhibitory effect of TGF-beta was assessed by the 3H-thymidine incorporation assay. For in vivo testing, xenograft tumors were produced by subcutaneous injection of tumor cells into immunodeficient nude mice. The tumorigenicity of these TbetaR-II transfected cells was tested. Wild-type Renca cells and cells transfected with the control vector were also tested for comparison.

RESULTS

Expression of TbetaR-II mRNA was evident in Renca cells after transfection with the TbetaR-II construct. In vitro sensitivity to the growth inhibitory effect of TGF-beta was restored. This effect of TGF-beta was reversible with a neutralizing antibody specific for the extracellular domain of TbetaR-II. Xenografts grown from TbetaR-II transfected cells were significantly smaller, weighed less, and developed tumors later than those developed from wild-type Renca cells and those transfected with the control vector.

CONCLUSIONS

We conclude that TbetaR-II is a central mediator of tumorigenicity in Renca cells. As with other tumor suppressor genes, the loss of TbetaR-II expression allows for the development of an aggressive phenotype.

Extracellular polymerization of 3-hydroxyalkanoate monomers with the polymerase of Alcaligenes eutrophus

Previous investigations on the role of the polymerase in the synthesis of poly-3-hydroxybutyrate (PHB) are reviewed, and the results from earlier in vitro studies on the activity and selectivity of the polymerase of Alcaligenes eutrophus are discussed. In the present study the effect of glycerol on stabilizing the polymerase after purification and on eliminating the lag phase in in vitro polymerization reactions of 3-hydroxybutyl CoA (HBCoA), and 3-hydroxyvaleryl CoA (HVCoA) are described. K(M) values were determined for the activity of the polymerase with both HBCoA and HVCoA, and the rates of propagation for both monomers were estimated. With a racemic mixture of HBCoA, the enzyme polymerized only the [R] monomer.

Extracellular degradation of medium chain length poly(beta-hydroxyalkanoates) by Comamonas sp

The PHA-degrading isolate, strain P37C, was enriched from residential compost for its ability to hydrolyze the medium chain length PHA, poly(beta-hydroxyoctanoate) (PHO). It was subsequently found to grow on a wide range of PHAs, including both short chain length and medium chain length PHAs. The isolate was identified as belonging to the genus Comamonas. Strain P37C formed clear zones on poly(beta-hydroxybutyrate) (PHB), (PHO) and poly(beta-hydroxyphenylvalerate) (PHPV) overlay plates. PHA clear zone tubes were prepared using seven different kinds of PHAs, ranging from PHB with four-carbon repeating units, to poly(beta-hydroxyoctanoate-co-beta-hydroxyundecanoate) (PHOU) with 8- and 11-carbon repeating units. There was a direct correlation between PHA side chain length and rate of hydrolysis of the PHAs. A series of PHOUs containing varying percentages of unsaturated bonds were used to make a series of epoxidized PHOUs (PHOEs) with varying percentages of epoxy functions. Results of clear zone tube assays showed that these functionalized PHAs were all biodegradable by strain P37C, and there was no apparent correlation between rate of biodegradation and the proportion of functional groups in the PHAs. Biodegradability of these PHAs was verified using respirometry and enzyme assays. Cell-free supernatants containing activity toward PHAs were prepared, and strain P37C was shown to synthesize at least two distinct PHA depolymerases for the hydrolysis of SCL and MCL PHAs.

Temporal trends in coal workers' pneumoconiosis prevalence. Validating the National Coal Study results

Evidence from four successive rounds of the National Study of Coal Workers' Pneumoconiosis indicates diminishing prevalence of coal workers' pneumoconiosis (CWP) from 1969 to 1988. However, methodological inconsistencies across surveys have raised concerns. This study confirms the reported downward trend in CWP prevalence, utilizing a standardized methodological approach. A single team of three x-ray readers using the 1980 International Labour Office classification independently re-evaluated 3143 Appalachian-region cases to derive overall, tenure- and age-specific prevalences. Prevalence of small rounded opacities declined, with 12.7% in Round 1, 11.2% in Round 2, 3.0% in Round 3, and 3.9% in Round 4. These findings support the National Institute for Occupational Safety and Health's recommendation of a reduced exposure limit of 1 mg/m3 because the present coal dust standard does not sufficiently protect miners against adverse health effects over a working lifetime of exposures.

Absence of expression of transforming growth factor-beta type II receptor is associated with an aggressive growth pattern in a murine renal carcinoma cell line, Renca

Transforming growth factor-beta1 (TGF-beta1) inhibits the proliferation of many cancer cells. However, tumor cells frequently become resistant to this inhibitory effect due to the absence of TGF-beta receptor (TbetaR) expression. This study reports the nature of TGF-beta sensitivity in an aggressive murine renal carcinoma cell line, Renca, investigated in a series of experiments. The growth of Renca cells, in tissue culture, was not sensitive to the inhibitory effect of TGF-beta1 with doses ranging from 0.1 to 10 ng./ml., nor was this cell line sensitive to the effect of TGF-beta1 in inducing the expression of plasminogen activator inhibitor-I. Renca cells expressed TGF-beta1 mRNA and protein, as determined by RT-PCR and ELISA, respectively. The level of TGF-beta1 production by Renca cells was moderate, thus eliminating the possibility that endogenous TGF-beta1 production might be masking the effect of TGF-beta sensitivity. Furthermore, Renca cells expressed TbetaR-I mRNA, but did not express TbetaR-II mRNA, suggesting that the absence of this receptor may be the cause of TGF-beta insensitivity. Additionally, a vector containing the TbetaR-II cDNA was transiently transfected into Renca cells. The inhibitory effect of TGF-beta1 was introduced in Renca cells after transfection with this receptor. At the same time, the growth rate of these cells diminished significantly when compared with that of the wild type Renca cells, as judged by the rate of [3H]-thymidine incorporation in the absence of any exogenous TGF-beta1. These observations demonstrated that Renca cells lack the functional TbetaR-II and suggest that their aggressive growth pattern is due, at least in part, to their insensitivity to TGF-beta.

Nonulcer dyspepsia and Helicobacter pylori, with comment on posteradication symptoms

In two London hospitals during five months in 1997, among patients referred for esophago-gastroduodenoscopy, 250 complained of dyspepsia for more than two days per week. Of these, 190 gave informed consent to enter a study of H. pylori infection in nonulcer dyspepsia, but only 42 (22%) were found to have H. pylori infection without a peptic ulcer. At the time of this interim report, of these patients, 26 had been treated with omeprazole, amoxicillin, and clarithromycin, four weeks had elapsed since treatment, and H. pylori had been eradicated. Of these 26 patients, 15 (58%) had lost nearly all their symptoms. This is the first report of loss of symptoms in patients with nonulcer dyspepsia after treatment with omeprazole, amoxicillin and clarithromycin with early follow-up after four weeks. However, this was not a placebo-controlled study and the number of patients was small, so it is not possible to conclude whether H. pylori could be one cause of nonulcer dyspepsia. The increasing incidence of posteradication esophagitis is discussed as is the possible need for more sophisticated management of nonulcer dyspepsia.

Non-cardiac chest pain: why was a brief intervention apparently ineffective?

BACKGROUND

Patients who present with chest pain but have normal coronary angiography and who are told by their cardiologist that they do not have heart disease, have a poor symptomatic, psychological and quality of life outcome and remain concerned about a serious cause of their symptoms. They frequently complain they have not had enough information. The study aimed to test the effectiveness and acceptability of a brief psychological intervention based on cognitive behavioural principles.

METHODS

Consecutive patients with chest pain and normal angiograms were assessed and invited to take part in a randomized controlled evaluation. The intervention consisted of an individualized information and discussion session by a specially trained cardiac nurse, together with a handout and cassette providing information and advice and telephone follow-up to discuss progress, answer questions and reiterate advice.

RESULTS

The treatment proved to be unacceptable to some patients and there was no evidence of efficacy.

CONCLUSIONS

Implications for the preparation of patients undergoing angiography and for the timing and delivery of information and advice following a negative result are discussed.

Vertical transmission of toxoplasma by human immunodeficiency virus-infected women

OBJECTIVE

Our goal was to determine the frequency of mother-to-child transmission of Toxoplasma gondii from human immunodeficiency virus-infected mothers who are also chronically infected with T. gondii.

STUDY DESIGN

One hundred thirty-eight women were entered into a prospective study of human immunodeficiency virus infection in pregnancy. The women were seen at enrollment, during the third, sixth, and eighth months of pregnancy (except those enrolled later in pregnancy or at delivery), at 2 and 6 months post partum, and at 6-month intervals thereafter through 4 years after delivery. Standardized interviews and physical examinations were performed, and blood was drawn at each visit. Toxoplasma serologic testing was performed on the sample drawn earliest in pregnancy; the Sabin-Feldman dye test for immunoglobulin G antibodies and enzyme-linked immunoassays for immunoglobulins M, A, and E were used. Univariate analysis for categoric variables was performed with chi2 and two-tailed Fisher exact tests, and for continuous variables the Student t test was used. Statistical Analysis System procedures were followed.

RESULTS

Twenty-eight of 138 (20.2%) women who had positive test results for human immunodeficiency virus had positive findings of the Sabin-Feldman dye test. Serologic status for T. gondii did not correlate with age, immune status, parity, or drug use. One of 27 children born to women who were seropositive for both human immunodeficiency virus and T. gondii (one child's serologic status for T. gondii was unknown) had Sabin-Feldman dye test antibodies beyond age 6 months (3.7%, 95% confidence interval 0.09% to 18.9%). Among the cohort of human immunodeficiency virus-infected mothers the rate of mother-to-child human immunodeficiency virus transmission did not vary with maternal Toxoplasma status. However, with sample sizes of 28 and 110, respectively, for the mothers who were T. gondii seropositive and seronegative, the power to detect a difference in the human immunodeficiency virus transmission rate between these groups would be relatively small.

CONCLUSIONS

Transmission of T. gondii from a chronically infected mother can occur in the setting of a human immunodeficiency virus infection, but this is not a common phenomenon. In a small cohort of human immunodeficiency virus-infected women we did not observe its occurrence among those without severe immunocompromise.