Experimental investigation of nasal airflow

The airway geometry of the nasal cavity is manifestly complex, and the manner in which it controls the airflow to accomplish its various physiological functions is not fully understood. Since the complex morphology and inaccessibility of the nasal passageways precludes detailed in-vivo measurements, either computational simulation or in-vitro experiments are needed to determine how anatomical form and function are related. The fabrication of a replica model of the nasal cavity, of a high optical clarity and derived from in-vivo scan data is described here, together with characteristics of the flow field investigated using particle image velocimetry (PIV) and flow visualization. Flow visualization is shown to be a capable and convenient technique for identifying key phenomena. Specifically the emergence of the jet from the internal nasal valve into the main cavity, how it impacts on the middle turbinate, and the large enhancement of dispersion that accompanies the initial appearance of flow instability are revealed as particularly significant features. The findings from the visualization experiments are complemented by PIV imaging, which provides quantitative detail on the variations in velocity in different regions of the nasal cavity. These results demonstrate the effectiveness of the cavity geometry in partitioning the flow into high shear zones, which facilitate rapid heat transfer and humidification from the nasal mucosa, and slower zones affording greater residence times to facilitate olfactory sensing. The experimental results not only provide a basis for comparison with other computational modelling but also demonstrate an alternative and flexible means to investigate complex flows, relevant to studies in different parts of the respiratory or cardiovascular systems.

Risk factors for hide contamination of Scottish cattle at slaughter with Escherichia coli O157

In the slaughter processing of cattle, contaminated hides have been identified as one of the major sources of Escherichia coli O157 carcase contamination. Logistic regression analysis was applied to data collected in a large scale study in Scotland involving 222 cattle forming 34 groups sent for slaughter from 30 farms to 10 slaughterhouses. Aspects of individual animal characteristics, farm management practices and slaughterhouse features were examined to identify potential risk factors for hide contamination at harvest. Two models were developed, the first in which slaughterhouse was modelled as a fixed effect, and a second model where slaughterhouse and farm groups were modelled as random effects. In the first model, there was a significantly increased risk of a carcase testing positive for E. coli O157 on the hide if either the hide of the carcase immediately before or after it on the line was contaminated (OR 3.6; 95% CI: 1.4-9.9). If both adjacent carcases had contaminated hides, the odds ratio for the study carcase having a contaminated hide rose to 11.5 (95% CI: 4.4-32.5). If animals were held in lairage, receiving hay as feed appeared to have a protective effect on hide contamination. Transportation to the slaughterhouse by haulier, as opposed to transport by the farmer, was associated with a 5.4 increase in the odds of E. coli O157 contamination. The use of a crush in the lairage, often employed when reading ear tags, was also found to significantly increase the odds of hide contamination with E. coli O157. In the second model, the inclusion of slaughterhouse and farm group as random effects resulted in two of the previously identified factors being associated with hide contamination. If at least one of the adjacent carcases on the line had a contaminated hide, the associated odds ratio was 6.6 (95% CI: 2.8-15.9), which rose to 22.7 (95% CI: 9.3-55.5) if both adjacent hides were contaminated. Receiving hay in lairage was found to be important to the model, although not significant in itself (OR 0.005; 95% CI: 1.2e(-6)-20.7). These results suggest that modifiable risk factors for hide contamination exist. However, in order best to reduce the prevalence of hide contamination at slaughter, individual slaughterhouse risk assessment and intervention strategies are appropriate.

Spatial and temporal epidemiology of sporadic human cases of Escherichia coli O157 in Scotland, 1996-1999

In Scotland, between 1995 and 2000 there were between 4 and 10 cases of illness per 100000 population per year identified as being caused by Escherichia coli O157, whereas in England and Wales there were between 1 and 2 cases per 100000 population per year. Within Scotland there is significant regional variation. A cluster of high rate areas was identified in the Northeast of Scotland and a cluster of low rate areas in central-west Scotland. Temporal trends follow a seasonal pattern whilst spatial effects appeared to be distant rather than local. The best-fit model identified a significant spatial trend with case rate increasing from West to East, and from South to North. No statistically significant spatial interaction term was found. In the models fitted, the cattle population density, the human population density, and the number of cattle per person were variously significant. The findings suggest that rural/urban exposures are important in sporadic infections.

Preliminary x-ray characterization of authentic providence virus and attempts to express its coat protein gene in recombinant baculovirus

Providence Virus (PrV) is a non-envoloped, T = 4 icosahedral beta-tetravirus that undergoes autocatalytic cleavage of its coat protein precursor after capsid assembly. This is also a well characterized function of Nudaurelia capensis omega virus (NomegaV), a member of the related omegatetraviruses, whose x-ray structure has been determined. Virus-like particle (VLP) production of PrV in a recombinant baculovirus expression system was attempted to obtain high VLP yields for comparison of structural and autocatalytic active site properties between these virus groups. This resulted in insoluble aggregates of PrV coat protein even though NomegaV VLPs have been successfully produced in the same system. Betatetraviruses may be more dependent on compartmentalization and availability of their full-length genome for proper folding and assembly. However, crystals were grown of limited quantities of authentic PrV produced in cell culture and a partial X-ray data set collected to 3.8 A resolution. The virus particle position and orientation in the unit cell was determined by space group consideration and rotation function analysis. A phasing model, based on NomegaV, was developed to initiate the structure solution of PrV.

The effect of prepartum antibiotics on the type of neonatal bacteraemia: insights from the MRC ORACLE trials

We analysed the type of bacteraemia before discharge from Neonatal Intensive Care Units in babies born to women randomised to the MRC ORACLE Trials. There was no evidence for an effect of oral antibiotics given prior to delivery on bacteraemia due to gram negative or enterococci bacteria, but Group B streptococcal (GBS) bacteraemia was significantly reduced in women with preterm prelabour rupture of the membranes (1.58% to 0.55%, relative risk 0.34; 95% CI: 0.17-0.70). There was no detectable effect in women in spontaneous preterm labour with intact membranes as the risk of GBS bacteraemia in their babies was very small regardless of treatment.

Retrospective study of bacterial infective arthritis in 31 dogs

OBJECTIVES

To characterise the presenting signs and pathological changes of canine bacterial infective arthritis in 31 dogs, and to document the response to different treatment regimens. Risk factors that may predispose joints to bacterial infective arthritis and influence the success of treatment were also investigated.

METHODS

A retrospective review of cases of bacterial infective arthritis that were presented to three university veterinary referral hospitals over a five-year period (January 1997 to January 2002) was performed.

RESULTS

The elbow joint (38 per cent) and stifle joint (44 per cent) were most commonly affected. Radiographic changes consistent with pre-existing osteoarthritis were identified in 14 joints, which had no history of previous surgery (articular or periarticular) or penetrating wound. No significant difference (P = 0.78) was identified between the outcome of combined surgical and medical management, and medical management alone. There were trends for poorer outcomes with increased bodyweight of the dog, longer duration of lameness and a higher nucleated cell count of the affected joint fluid at presentation. The overall infection rate for articular surgical procedures at one institution was 1-3 per cent.

CLINICAL SIGNIFICANCE

Medical and/or surgical management were usually successful in resolving infection (94 per cent). However, they were frequently unsuccessful in restoring full joint function; this may in part have been due to the nature of the underlying joint

Effects of Carnitine Supplementation on Muscle Metabolism by the Use of Magnetic Resonance Spectroscopy and Near-Infrared Spectroscopy in End-Stage Renal Disease

BACKGROUND/AIM

A defect in skeletal muscle mitochondrial metabolism develops in patients with chronic renal failure on haemodialysis. Treatment with carnitine, a compound essential for normal mitochondrial function, has been suggested to have significant benefits in such patients, so we carried out a study to see if carnitine acts by improving muscle bioenergetics and function.

METHODS

In a phase II randomised double-blind trial, patients with end-stage renal disease received placebo or intravenous L-carnitine (20 mg/kg dry body weight three times weekly after haemodialysis) for 16 weeks (n = 13 in each group). 31P magnetic resonance spectroscopy, 1H magnetic resonance imaging and near-infrared spectroscopy were used to measure muscle bioenergetics and function at baseline and at 16 weeks.

RESULTS

There were no significant differences between groups at baseline. Mean plasma carnitine rose 10-fold in the carnitine group but was unchanged in the placebo group. L-carnitine had no statistically significant effect on any of the parameters measured. The rate of proton efflux from muscle, as a measure of tissue perfusion, was low in both groups and was not affected by treatment.

CONCLUSIONS

The study failed to show any significant effect of 16 weeks' L-carnitine supplementation on these objective measures of muscle metabolism and function. Slow proton efflux from muscle provides evidence supporting low blood flow and, therefore, decreased oxygen availability, as an underlying mechanism for muscle mitochondrial dysfunction in this disorder.

Neuropsychological and Information Processing Performance and Its Relationship to White Matter Changes Following Moderate and Severe Traumatic Brain Injury: A Preliminary Study

Reductions in information processing speed have frequently been reported following moderate and severe traumatic brain injuries (TBIs), consistent with the effects of diffuse white matter damage. Although the corpus callosum (CC) is a common site for diffuse damage following TBI, the effects of this damage on information processing speed have not been adequately examined. This study assessed a TBI group and a matched control group on tests of attention, memory, fluency, and set shifting ability, together with reaction time (RT) tasks requiring the inter- and intrahemispheric processing of visual and tactile information. The RT tasks were designed to target the cognitive functions that are likely to be affected by diffuse white matter damage, including damage to the CC. The TBI group demonstrated deficits in verbal and visual fluency and verbal memory. They were also slower on the visual and tactile RT tasks, were more affected by task complexity, and slower on RT tasks requiring the interhemispheric transfer of information. In fact, one of the interhemispheric tactile RT tasks proved to be the most discriminating of all the cognitive and RT measures. MRIs completed on a subset of TBI participants indicated that the mean CC measurements were 5% to 19% smaller than a normative control group, with the most atrophied areas being the isthmus and anterior midbody. Although white matter atrophy was moderately related to visual and tactile RT performance, and total hippocampal volume related to memory performance, CC area was not related to many of the tasks that were designed to tap interhemispheric processing. None of the standard cognitive tests correlated with outcome in the TBI group, but 1 of the tactile RT measures was significantly related to 2 measures of outcome.

Frozen storage of Escherichia coli O157 in buffered peptone water and its detection on bovine carcasses

The adaptation of a standard Escherichia coli O157 isolation method involving immunomagnetic separation and a period of frozen storage was investigated. A series of experiments was designed to test the recovery of a bovine strain of E. coli O157 from buffered peptone water after a period of frozen storage at -80 degrees C. The effects of the addition of glycerol at 5 and 10%, freezing time, the number of freeze-thaw cycles, the method of freezing and the method of thawing, the inclusion of a resuscitation-and-incubation step, and the sensitivity of the isolation method were investigated. The most effective method of storing frozen samples for 6 months and recovering strains of E. coli O157 after storage was found to involve 6 h of incubation of sample material in buffered peptone water at 37 degrees C before frozen storage at -80 degrees C with 10% glycerol, a rapid thaw after frozen storage, and resuscitation at 27 degrees C for 1 h and incubation at 37 degrees C for 1 h to allow freeze-injured and stressed bacteria to recover with a period of growth prior to immunomagnetic separation isolation. There was no significant decrease in log counts of a bovine strain E. coli O157 over 6 months of frozen storage in buffered peptone water with 10% glycerol. With this method, it was possible to isolate E. coli O157 from naturally infected bovine carcasses after a period of frozen storage.

Testing paleolimnological predictions with molecular data: the origins of Holarctic Eubosmina

Zooplankton of the family Bosminidae have a unique paleolimnological record in many Holarctic lakes that provides a near continuous record of morphological change for thousands of years. If this morphological change could be interpreted reliably, then a rarely achieved direct observation of macroevolution would be feasible. We tested paleolimnological predictions derived from morphological variation found in the genus Eubosmina using mtDNA and nuclear DNA sequence variation from geographically distant Holarctic sites. The mtDNA and nDNA trees were congruent but genetic divergence was inversely associated with morphological divergence. The three most genetically divergent groups belonged to Eubosmina longispina, whose phylogeography and genetic divergence was consistent with glacial vicariance. The genetic evidence also supported the hypothesis that at least two Nearctic species were recent European introductions. Finally, the genetic evidence was consistent with paleolimnology in the finding of several proposed species undergoing rapid morphological evolution and being post-glacially derived from European E. longispina. The results suggested that lacustrine bosminids are susceptible to geographic speciation processes, and that morphological interpretation of diversity in paleolimnology can be markedly improved by genetic studies.

Development of a youth survey to measure risk behaviors, attitudes and assets: examining multiple influences

Currently, most surveys assessing adolescent health concerns focus primarily on risk behaviors and negative influences rather than positive influences such as assets. The purpose of this paper is to describe the development and validation of the Adolescent Health Attitude and Behavior Survey (AHABS). This instrument was developed to measure the prevalence of youth health risk behaviors, attitudes towards adolescent sexual behavior and youth assets in a statewide evaluation effort. The questionnaire was completed by 4368 public high school students in Grades 9-12. Content validity was established through an extensive review of literature, a group process and factor analyses. Reliability was established through Cronbach's alpha coefficients. Factor loadings ranged from 0.48 to 0.84 for scales measuring attitudes towards adolescent sexual behavior and alpha coefficients ranged from 0.61 to 0.81. Factor loadings ranged from 0.34 to 0.90 for scales measuring youth assets and alpha coefficients ranged from 0.69 to 0.85. Because of several limitations (e.g. construct validity was not measured), additional development work is needed. Therefore, the AHABS is still in a developing, but promising, state. Additional psychometric work will provide program practitioners and evaluators with a psychometrically sound tool to measure behaviors, attitudes and assets.

Cessation of feline calicivirus shedding coincident with resolution of chronic gingivostomatitis in a cat

Feline calicivirus (FCV) shedding and oral bacterial flora were monitored over a period of 22 months in a case of feline gingivostomatitis (FGS). The cat was treated daily with 50 mg thalidomide capsules by mouth, and 200 mg lactoferrin powder was applied directly to the lesions. Clinical signs began to resolve after 11 months when, in addition to treatment, the diet had been changed to an additive-free cat food supplemented with antioxidant vitamins A, D3 and E. Resolution of clinical signs of FGS coincided with the cessation of FCV shedding, and this is the first report documenting such an association. Which part of the treatment, if any, contributed to the cure requires further investigation.

Quantitative criteria for insomnia

Formal diagnostic systems (DSM-IV, ICSD, and ICD-10) do not provide adequate quantitative criteria to diagnose insomnia. This may not present a serious problem in clinical settings where extensive interviews determine the need for clinical management. However, lack of standard criteria introduce disruptive variability into the insomnia research domain. The present study reviewed two decades of psychology clinical trials for insomnia to determine common practice with regard to frequency, severity, and duration criteria for insomnia. Modal patterns established frequency (> or =3 nights a week) and duration (> or =6 months) standard criteria. We then applied four versions of severity criteria to a random sample and used sensitivity-specificity analyses to identify the most valid criterion. We found that severity of sleep onset latency or wake time after sleep onset of: (a) > or =31 min; (b) occurring > or =3 nights a week; (c) for > or =6 months are the most defensible quantitative criteria for insomnia.

ORACLE--antibiotics for preterm prelabour rupture of the membranes: short-term and long-term outcomes

Preterm prelabour rupture of the foetal membranes (pPROM) is the most common antecedent of preterm birth and can lead to death, neonatal disease and long-term disability. Previous small trials of antibiotics for pPROM suggested some health benefits for the neonate, but the results were inconclusive. A large, randomized, multicentre trial was undertaken to try to resolve this issue. In total, 4826 women with pPROM were randomized to one of four treatments: 325 mg co-amoxiclav plus 250 mg erythromycin, co-amoxiclav plus erythromycin placebo, erythromycin plus co-amoxiclav placebo, or co-amoxiclav placebo plus erythromycin placebo, four times daily for 10 d or until delivery. The primary outcome measure was a composite of neonatal death, chronic lung disease or major cerebral abnormality on ultrasonography before discharge from hospital. The analysis was undertaken by intention to treat. Indications of short-term respiratory function, chronic lung disease and major neonatal cerebral abnormality were reduced with the prescription of erythromycin. In contrast, the use of co-amoxiclav was associated with a significant increase in the occurrence of neonatal necrotizing enterocolitis.

CONCLUSION

Prophylactic antibiotics can play a role in preterm prelabour rupture of the membranes in reducing infant morbidity.

Invasive testing for the karyotyping of mid-trimester intrauterine fetal death (IUFD): a pilot study

INTRODUCTION

Aneuploidy remains a common cause of fetal loss after the first trimester. Conventional karyotyping from fetal solid tissues post-delivery unfortunately has a poor success rate particularly where the fetus is macerated. To overcome this we obtained amniocentesis and/or chorionic villus samples from mid-trimester intrauterine fetal deaths (IUFDs) prior to medical termination of pregnancy.

SUBJECTS

Ten women with diagnosed IUFD between 12 and 24 weeks' gestation underwent amniocentesis and/or CVS performed after counselling.

RESULTS

Successful karyotypes were obtained in all pregnancies. Five of the ten pregnancies were complicated by aneuploidy (two with trisomy 21, two with trisomy 18, and one with trisomy 13).

CONCLUSION

The high rate of aneuploidy (50%) in this small cohort emphasises the need for karyotyping. A successful karyotype in all ten pregnancies demonstrates the value of offering these procedures before a termination of pregnancy. We would recommend the adoption of this approach in the management of IUFD occurring after the first trimester.

Determination of gestational age after the 24th week of gestation from fetal kidney length measurements

OBJECTIVE

To evaluate the application of kidney length measurement to the determination of gestational age between the 24th and 38th weeks and to compare its accuracy with that of other fetal biometric indices.

STUDY DESIGN

Seventy-three women with singleton uncomplicated pregnancies underwent standard ultrasound fetal biometry and kidney length measurement every 2 weeks between 24 and 38 weeks' gestation. These measurements were used to date the pregnancies relative to crown-rump length dating between 8 and 10 weeks' gestation. Linear regression models for estimation of gestational age were derived from the biometric indices and kidney length. In addition, stepwise regression models were constructed to determine the best model for determining gestational age between 24 and 38 weeks. Comparisons were then made between the accuracy of these models in the determination of gestational age.

RESULTS

The best model for estimating gestational age in late pregnancy included the variables kidney length, biparietal diameter, head circumference, femur length and abdominal circumference. This model accurately predicted gestational age with a standard error of +/- 8.48 days. A model including kidney length, biparietal diameter, head circumference and femur length accurately predicted gestational age with a standard error of +/- 8.57 days. These models were slightly more accurate than models derived from the biometric indices of biparietal diameter, head circumference and femur length (+/- 9.87 days), biparietal diameter, head circumference, femur length and abdominal circumference (+/- 9.45 days) and biparietal diameter and femur length (+/- 9.9 days). Kidney length and femur length were the most accurate single parameters for predicting gestational age using simple linear regression models (+/- 10.29 and 10.96 days, respectively); the abdominal circumference was the least accurate (+/- 14.54 days).

CONCLUSION

Kidney length is a more accurate method of determining gestational age than the fetal biometric indices of biparietal diameter, head circumference, femur length and abdominal circumference between 24 and 38 weeks' gestation. When combined with biparietal diameter, head circumference and femur length, the precision of dating is improved by 2 days. This measurement is easy to make and could therefore be easily incorporated into the model for dating pregnancies after 24 weeks of gestation, in particular when measurements of the biparietal diameter and head circumference are difficult.

Mitochondrial dysfunction in Friedreich's ataxia: from pathogenesis to treatment perspectives

Friedreich's ataxia (FRDA), the most common inherited ataxia, is an autosomal recessive degenerative disorder caused by a GAA triplet expansion or point mutations in the FRDA gene on chromosome 9q13. The FRDA gene product, frataxin, is a widely expressed mitochondrial protein, which is severely reduced in FRDA patients. The demonstration that deficit of frataxin in FRDA is associated with mitochondrial iron accumulation, increased sensitivity to oxidative stress, deficit of respiratory chain complex activities and in vivo impairment of cardiac and skeletal muscle tissue energy metabolism, has established FRDA as a "new" nuclear encoded mitochondrial disease. Pilot studies have shown the potential effect of antioxidant therapy based on idebenone or coenzyme Q10 plus Vitamin E administration in this condition and provide a strong rationale for designing larger randomized clinical trials.

A quantitative study of bioenergetics in skeletal muscle lacking utrophin and dystrophin

Muscle energetics and function were investigated in the hindlimb of mice lacking dystrophin (mdx), utrophin and dystrophin (utr-dys) and controls (C57Bl/10) using 31P and 1H magnetic resonance techniques, electrical nerve stimulation and direct biochemical analysis. At rest, [adenosine triphosphate] and [total creatine] were lowest in utr-dys, while [inorganic phosphate] was elevated. Calculated [adenosine diphosphate] was 3-fold higher in mdx and 5-fold higher in utr-dys than in controls, consistent with an increased adenosine triphosphate requirement for ion pump activity. During stimulation, force production was low only in utr-dys, and this was reflected in the bioenergetic changes. Initial recovery rates of [phosphocreatine] and [adenosine diphosphate] after stimulation were rapid in all groups, indicative of normal mitochondrial adenosine triphosphate production in utr-dys and mdx. Recovery of pH was slow in utr-dys. The data indicate that the severe abnormalities which are present in the absence of utrophin and dystrophin leave basic muscle energetics intact and appear confined to processes involving the sarcolemma.

Rate acceleration and long-branch attraction in a conserved gene of cryptic daphniid (Crustacea) species

The nuclear large subunit (LSU) rRNA gene is a rich source of phylogenetic characters because of its large size, mosaic of slowly and rapidly evolving regions, and complex secondary structure variation. Nevertheless, many studies have indicated that inconsistency, bias, and gene-specific error (e.g., within-individual gene family variation, cryptic sequence simplicity, and sequence coevolution) can complicate animal phylogenies based on LSU rDNA sequences. However, most of these studies sampled small gene fragments from expansion segments--among animals only five nonchordate complete LSU sequences are published. In this study, we sequenced near-complete nuclear LSU genes from 11 representative daphniids (Crustacea). The daphniid expansion segment V6 was larger and showed more length variation (90-351 bp) than is found in all other reported LSU V6 sequences. Daphniid LSU (without the V6 region) phylogenies generally agreed with the existing phylogenies based on morphology and mtDNA sequences. Nevertheless, a major disagreement between the LSU and the expected trees involved a positively misleading association between the two taxa with the longest branches, Daphnia laevis and D. occidentalis. Both maximum parsimony (MP) and maximum likelihood (ML) optimality criteria recovered this association, but parametric simulations indicated that MP was markedly more sensitive to this bias than ML. Examination of data partitions indicated that the inconsistency was caused by increased nucleotide substitution rates in the branches leading to D. laevis and D. occidentalis rather than among-taxon differences in base composition or distribution of sites that are free to vary. These results suggest that lineage-specific rate acceleration can lead to long-branch attraction even in the conserved genes of animal species that are almost morphologically indistinguishable.

Screening for diabetic retinopathy is well received by patients and may improve self-management intentions

AIMS

To investigate patients' views of screening for diabetic retinopathy and the effects of the screening process on health beliefs and behavioural intentions.

SETTING

A retinal screening clinic at a GP surgery in SW England.

METHODS

Questionnaires administered before and immediately after screening by retinal photography.

RESULTS

One hundred patients attended (94% of those invited); 12 had Type 1 and 88 Type 2 diabetes. Over 90% found the information, and seeing their retinal photograph, helpful. Sixty-three were found to have no problem and 37 had some type of eye problem detected. Overall, patients rated the news given at screening as better than expected (P < 0.001) and even those found to have problems mostly rated the news as good (P < 0.001). Detection of problems led patients to rate their recent eye health more negatively, but to be less pessimistic about future deterioration (P < 0.01). Patients with diabetes-related eye problems were more likely (P < 0.05) to say that they both should and would make changes to their self-management, but only after controlling for duration of diabetes. Those who had had diabetes longest declared least intention to change.

CONCLUSIONS

Screening by retinal photography is acceptable to patients. Results suggest that screening modified health beliefs but had limited effect on behavioural intentions, with patients of longer disease duration being more reluctant to change their self-management. Opportunities during retinal screening for advice on self-management could be more effectively exploited.

Effectiveness of laundry washing agents and conditions in the removal of cat and dust mite allergen from bedding dust

BACKGROUND

There is limited information about the removal of allergens by laundry washing.

OBJECTIVE

The purpose of this investigation was to determine the dynamics of the removal of mite allergen (Der p 1) and cat allergen (Fel d 1) from bed dust during simulated laundry processes.

METHODS

Three studies were performed. The first compared combinations of 4 laundry agents (water alone, soap, detergent with enzymes, and detergent without enzymes), 4 temperatures (15 degrees, 25 degrees, 45 degrees, and 60 degrees C), and 3 extraction times (5, 20, and 60 minutes). The second study examined allergen extraction by 11 common brands of detergents at 25 degrees and 45 degrees C for 5 minutes. The third study compared 4 detergents containing enzymes before and after the denaturation of their enzymes. To measure the quantity of allergens extracted, each study used an ELISA assay as well as a more sensitive but semiquantitative Halogen immunoassay to detect any allergens remaining after the simulated laundry extraction.

RESULTS

Study 1 showed that detergents extracted more of both Fel d 1 and Der p 1 than either soap or water alone and that almost all allergens were extracted within 5 minutes at 25 degrees. However, washing at 60 degrees C extracted slightly more Fel d 1 and denatured Der p 1, resulting in lower residual amounts of both allergens. Study 2 showed that all of the commercial detergents performed similarly. Study 3 showed that the presence of enzymes in detergent formulations did not produce a significant effect on the extraction of allergens.

CONCLUSION

Using detergent solutions at 25 degrees for at least 5 minutes was sufficient to extract most mite and cat allergen from dust of bedding.

A longitudinal study of quantitative uterine blood flow with the use of color power angiography in appropriate for gestational age pregnancies

OBJECTIVE

The purpose of this study was to examine longitudinally changes in quantified blood volume flow in the uterine arteries during pregnancy with the use of color power angiography.

STUDY DESIGN

Color power angiography was used to quantify volume flow in the uterine arteries of 57 women with singleton uncomplicated pregnancies between 20 and 38 weeks' gestation. Comparisons were made between blood flow in the 2 arteries in relation to the location of the placenta. Linear regression models were used to estimate gestational age derived volumetric changes in these vessels.

RESULTS

The diameter of the uterine arteries increased from 2.6 mm (SD, 0.2 mm) at 20 weeks to 4.8 mm (SD, 0.7 mm) at 38 weeks of gestation. The total uterine artery blood volume flow increased from 513 mL/min (SD, 127 mL/min) at 20 weeks to 970 mL/min (SD, 193 mL/min) at 38 weeks. The rate of increase was maximum between 20 and 24 weeks (39 mL/min per week). The laterality of the placenta significantly affected the diameter and blood volume flow in each uterine artery. The diameters on the ipsilateral side were significantly greater (by 10.8% +/- 2.4%) than the diameters on the contralateral side at all gestations (P < .05). Similarly, blood volume flow was significantly greater (by 17.8% +/- 2.2%) on the ipsilateral side at all gestations (P < .05). There were, however, no statistically significant differences between the vessel diameters and blood volume flow in those cases in which the placenta was central. Total uterine artery volume flow per kilogram of estimated fetal weight decreased from 1544 mL/kg per minute at 20 weeks to 296 mL/kg per minute at 38 weeks of gestation.

CONCLUSION

Total quantified uterine artery blood volume flow increases while blood flow per kilogram of fetal weight decreases with gestation. Blood volume flow in the ipsilateral artery to the placenta was significantly higher than that in the contralateral artery. Calculating total uterine artery volume flow by doubling the blood flow from 1 artery (as was previously done) may therefore either result in an over or underestimation, depending on the relationship between the vessel and the laterality of the placenta. Color power angiography is a simple noninvasive tool for determining uterine artery blood volume flow.

A mixture model for occupational exposure mean testing with a limit of detection

Information from detectable exposure measurements randomly sampled from a left-truncated log-normal distribution may be used to evaluate the distribution of nondetectable values that fall below an analytic limit of detection. If the proportion of nondetects is larger than expected under log normality, alternative models to account for these unobserved data should be considered. We discuss one such model that incorporates a mixture of true zero exposures and a log-normal distribution with possible left censoring, previously considered in a different context by Moulton and Halsey (1995, Biometrics 51, 1570-1578). A particular relationship is demonstrated between maximum likelihood parameter estimates based on this mixture model and those assuming either left-truncated or left-censored data. These results emphasize the need for caution when choosing a model to fit data involving nondetectable values. A one-sided likelihood ratio test for comparing mean exposure under the mixture model to an occupational exposure limit is then developed and evaluated via simulations. An example demonstrates the potential impact of specifying an incorrect model for the nondetectable values.

Abnormal Doppler velocimetry and blood flow volume in the middle cerebral artery in very severe intrauterine growth restriction: is the occurence of reversal of compensatory flow too late?

OBJECTIVES

To determine the time course of quantified volumetric flow and pulsatility index changes in the middle cerebral arteries of severe intrauterine growth restricted fetuses with absent or reversed end diastolic flow velocities (AREDFV) on umbilical artery Doppler with a view to defining the threshold for early intervention before the onset of reversal of adaptation.

SETTING

Fetal growth clinic of a large UK teaching hospital.

SAMPLE

Seventeen severe intrauterine growth restricted (AC < third centile for gestation and gender) fetuses with abnormal umbilical artery Doppler velocimetry and oligohydramnios (amniotic fluid index <third centile for gestation).

METHODS

One to three daily Doppler velocimetry and quantified volume flow of the middle cerebral artery Doppler velocimetry of the umbilical arteries and daily cardiotocography.

RESULTS

Reversal of adaptation occurred in eight fetuses, four of which ended as stillbirths and four as neonatal deaths. In two of these fetuses, this had already occurred before the diagnosis of intrauterine growth restriction. In the others, the onset was rapid and difficult to predict. Volume flow in the middle cerebral arteries decreased in those fetuses exhibiting reversal of adaptation but rose in the nine in which compensatory Doppler indices persisted. The decrease in volume flow occurred before the onset of reversal of adaptation in the pulsatility index. In the fetuses exhibiting reversal of adaptation, the rise in the pulsatility index was consistent over 48 hours compared with the physiological fluctuations in pulsatility index in some fetuses where the rise was only for 24 hours followed by a fall. Quantified volume flow fell in the fetuses before reversal of adaptation set-in. The umbilical artery Doppler indices fluctuated between absent and reversed end diastolic velocities within the same fetus irrespective of the changes in the middle cerebral artery Doppler indices.

CONCLUSION

Reversal of adaptation is of sudden onset and is associated with poor prognosis. Predicting its occurrence on Doppler indices is difficult as the changes may be very rapid. However, volume flow changes appear to be slower and of earlier onset than the pulsatility index changes. This may therefore be a more useful tool in predicting imminent reversal of adaptation and therefore early delivery.

Use of copper intrauterine devices and the risk of tubal infertility among nulligravid women

BACKGROUND

Previous studies of intrauterine devices (IUDs), many of which are no longer in use, suggested that they might cause tubal infertility. The concern that IUDs that contain copper--currently the most commonly used type--may increase the risk of infertility in nulligravid women has limited the use of this highly effective method of birth control.

METHODS

We conducted a case-control study of 1895 women recruited between 1997 and 1999. We enrolled 358 women with primary infertility who had tubal occlusion documented by hysterosalpingography, as well as 953 women with primary infertility who did not have tubal occlusion (infertile controls) and 584 primigravid women (pregnant controls). We collected information on the women's past use of contraceptives, including copper IUDs, previous sexual relationships, and history of genital tract infections. Each woman's blood was tested for antibodies to Chlamydia trachomatis. We used stratified analyses and logistic regression to assess the association between the previous use of a copper IUD and tubal occlusion.

RESULTS

In analyses involving the women with tubal occlusion and the infertile controls, the odds ratio for tubal occlusion associated with the previous use of a copper IUD was 1.0 (95 percent confidence interval, 0.6 to 1.7). When the primigravid women served as the controls, the corresponding odds ratio was 0.9 (95 percent confidence interval, 0.5 to 1.6). Tubal infertility was not associated with the duration of IUD use, the reason for the removal of the IUD, or the presence or absence of gynecologic problems related to its use. The presence of antibodies to chlamydia was associated with infertility.

CONCLUSIONS

The previous use of a copper IUD is not associated with an increased risk of tubal occlusion among nulligravid women whereas infection with C. trachomatis is.

Antioxidant treatment improves in vivo cardiac and skeletal muscle bioenergetics in patients with Friedreich's ataxia

Friedreich's ataxia (FA) is the most common form of autosomal recessive spinocerebellar ataxia and is often associated with a cardiomyopathy. The disease is caused by an expanded intronic GAA repeat, which results in deficiency of a mitochondrial protein called frataxin. In the yeast YFH1 knockout model of the disease there is evidence that frataxin deficiency leads to a severe defect of mitochondrial respiration, intramitochondrial iron accumulation, and associated production of oxygen free radicals. Recently, the analysis of FA cardiac and skeletal muscle samples and in vivo phosphorus magnetic resonance spectroscopy (31P-MRS) has confirmed the deficits of respiratory chain complexes in these tissues. The role of oxidative stress in FA is further supported by the accumulation of iron and decreased aconitase activities in cardiac muscle. We used 31P-MRS to evaluate the effect of 6 months of antioxidant treatment (Coenzyme Q10 400 mg/day, vitamin E 2,100 IU/day) on cardiac and calf muscle energy metabolism in 10 FA patients. After only 3 months of treatment, the cardiac phosphocreatine to ATP ratio showed a mean relative increase to 178% (p = 0.03) and the maximum rate of skeletal muscle mitochondrial ATP production increased to 139% (p = 0.01) of their respective baseline values in the FA patients. These improvements, greater in prehypertrophic hearts and in the muscle of patients with longer GAA repeats, were sustained after 6 months of therapy. The neurological and echocardiographic evaluations did not show any consistent benefits of the therapy after 6 months. This study demonstrates partial reversal of a surrogate biochemical marker in FA with antioxidant therapy and supports the evaluation of such therapy as a disease-modifying strategy in this neurodegenerative disorder.

Mitochondrial dysfunction in friedreich's ataxia

Friedreich ataxia (FRDA) is an autosomal recessive degenerative disorder caused in the vast majority of cases by a GAA triplet expansion in the FRDA gene on chromosome 9q13. The FRDA gene product, frataxin, is a widely expressed mitochondrial protein which is severely reduced in FRDA patients. Loss of the homologue of frataxin in yeast is associated with mitochondrial iron overload, increased sensitivity to oxidative stress and profound deficit of oxidative phosphorylation. The demonstration that the human pathology of FRDA is also characterised by mitochondrial iron accumulation, deficit of respiratory chain complex activities and in vivo deficit of tissue energy metabolism establishes FRDA as a 'new' nuclear encoded mitochondrial disease.

Regional and cellular localization of osteonectin/SPARC expression in connective tissue and cytotrophoblastic layers of human fetal membranes at term

Fetal membranes overlying the cervix in patients prior to and during labour, and within the rupture tear after spontaneous delivery at term, exhibit altered morphology. In this study we report that in comparison to mid-zone fetal membranes biopsies, these regions are characterized by increased expression of the matricellular protein osteonectin or SPARC (Secreted Protein Acidic and Rich in Cysteine). In the reticular layer, the percentage of vimentin positive mesenchymal cells immunoreactive for osteonectin increased in these regions from 3-4% to 25-33% and represented a fraction of the alpha-smooth muscle actin positive myofibroblasts elevated in the same regions. In the fibroblastic layer, the percentage of osteonectin positive cells increased from 1-5% to 8-13%; however, these did not exhibit the same relationship to the alpha-smooth muscle actin positive myofibroblasts in this layer. In the cytotrophoblastic layer the percentage of cytotrophoblastic cells immunoreactive for osteonectin increased from 1% to 6-12%. Elevation of in-situ detectable mRNA was also observed in the same cellular populations in this region. The incidence of cells positive for osteonectin mRNA or protein in the reticular layer correlated with morphological changes. Osteonectin has been implicated in the regulation of extracellular matrix turnover, and its pattern of expression suggests a role in the regional connective tissue and cytotrophoblastic changes proposed to be involved in the cleavage and rupture of fetal membranes.

How discriminatory is the objective structured clinical examination (OSCE) in the assessment of clinical competence of medical students?

A prospective collection and analysis of examination marks for three consecutive academic years was undertaken to determine the correlation between the objective structured clinical examination (OSCE) and various other components of medical students' examination, and also to examine how discriminatory the OSCE examination is in the assessment of clinical competence. Out of 388 students, 96.3% passed the examination at the first attempt. Of those who passed, 15.5% had merit while 1.0% had a distinction. When the OSCE component was excluded from the analysis, 11.6% and 2.8% had merits and distinctions, respectively, but when the clinical examination was excluded, there were 17.8% and 6.2% merits and distinctions, respectively. Correlations between the various components of the examination were significant except for that between the clinical examination and the project. Although the OSCE and clinical components of examinations for clinical students are complementary, the OSCE component awards more merit and distinction categories. Although there were statistically significant correlations between the various components of the examination, only 11% of the variability in clinical examination scores could be explained by the performance in OSCE suggesting that the different components are testing different aspects of the student's clinical competence. Completely replacing clinicals with an OSCE may not necessarily be the best way of assessing medical students' clinical competence.

No correlation between muscle A3243G mutation load and mitochondrial function in vivo

The authors studied the relationship between the percentage level of A3243G mitochondrial DNA mutation and the degree of mitochondrial dysfunction in vivo in nine individuals from four pedigrees using phosphorus MRS in muscle. There was no significant correlation between mutation load and maximum rate of adenosine triphosphate production (V(max)). V(max) was normal in a subject with 32% A3243G in muscle, which is in contrast with a previous observation of markedly reduced V(max) in a patient with only 6% A3243G in muscle. Factors besides mutation load, such as nuclear genes, influence expression of the A3243G mutation in vivo.

Broad-spectrum antibiotics for spontaneous preterm labour: the ORACLE II randomised trial. ORACLE Collaborative Group

BACKGROUND

Preterm birth after spontaneous preterm labour is associated with death, neonatal disease, and long-term disability. Previous small trials of antibiotics for spontaneous preterm labour have reported inconclusive results. We did a randomised multicentre trial to resolve this issue.

METHODS

6295 women in spontaneous preterm labour with intact membranes and without evidence of clinical infection were randomly assigned 250 mg erythromycin (n=1611), 325 mg co-amoxiclav (250 mg amoxicillin and 125 mg clavulanic acid; n=1550), both (n=1565), or placebo (n=1569) four times daily for 10 days or until delivery, whichever occurred earlier. The primary outcome measure was a composite of neonatal death, chronic lung disease, or major cerebral abnormality on ultrasonography before discharge from hospital. Analysis was by intention to treat.

FINDINGS

None of the trial antibiotics was associated with a lower rate of the composite primary outcome than placebo (erythromycin 90 [5.6%], co-amoxiclav 76 [5.0%], both antibiotics 91 [5.9%], vs placebo 78 [5.0%]). However, antibiotic prescription was associated with a lower occurrence of maternal infection.

INTERPRETATION

This trial provides evidence that antibiotics should not be routinely prescribed for women in spontaneous preterm labour without evidence of clinical infection.

Broad-spectrum antibiotics for preterm, prelabour rupture of fetal membranes: the ORACLE I randomised trial. ORACLE Collaborative Group

BACKGROUND

Preterm, prelabour rupture of the fetal membranes (pPROM) is the commonest antecedent of preterm birth, and can lead to death, neonatal disease, and long-term disability. Previous small trials of antibiotics for pPROM suggested some health benefits for the neonate, but the results were inconclusive. We did a randomised multicentre trial to try to resolve this issue.

METHODS

4826 women with pPROM were randomly assigned 250 mg erythromycin (n=1197), 325 mg co-amoxiclav (250 mg amoxicillin plus 125 mg clavulanic acid; n=1212), both (n=1192), or placebo (n=1225) four times daily for 10 days or until delivery. The primary outcome measure was a composite of neonatal death, chronic lung disease, or major cerebral abnormality on ultrasonography before discharge from hospital. Analysis was by intention to treat.

FINDINGS

Two women were lost to follow-up, and there were 15 protocol violations. Among all 2415 infants born to women allocated erythromycin only or placebo, fewer had the primary composite outcome in the erythromycin group (151 of 1190 [12.7%] vs 186 of 1225 [15.2%], p=0.08) than in the placebo group. Among the 2260 singletons in this comparison, significantly fewer had the composite primary outcome in the erythromycin group (125 of 1111 [11.2%] vs 166 of 1149 [14.4%], p=0.02). Co-amoxiclav only and co-amoxiclav plus erythromycin had no benefit over placebo with regard to this outcome in all infants or in singletons only. Use of erythromycin was also associated with prolongation of pregnancy, reductions in neonatal treatment with surfactant, decreases in oxygen dependence at 28 days of age and older, fewer major cerebral abnormalities on ultrasonography before discharge, and fewer positive blood cultures. Although co-amoxiclav only and co-amoxiclav plus erythromycin were associated with prolongation of pregnancy, they were also associated with a significantly higher rate of neonatal necrotising enterocolitis.

INTERPRETATION

Erythromycin for women with pPROM is associated with a range of health benefits for the neonate, and thus a probable reduction in childhood disability. However, co-amoxiclav cannot be routinely recommended for pPROM because of its association with neonatal necrotising enterocolitis. A follow-up study of childhood development and disability after pPROM is planned.

Knowledge of Down syndrome in pregnant women from different ethnic groups

The uptake of any screening test is influenced by knowledge of the condition being screened for. In the present study, the knowledge and the source of knowledge of women offered antenatal screening for Down syndrome (DS) was assessed by means of a self-administered questionnaire. The questionnaire was administered to 300 consecutive women booking for antenatal care, of the 245 (82%) women who completed and returned the questionnaire, 117 (48%) were Caucasian, 85 (35%) were Asian born outside the UK, 32 (13%) were Asian born in the UK and ten (4%) belonged to other categories. Only 30% of the cohort had a good understanding of the condition. Racial groups other than Caucasian had a poorer understanding of DS. The factors which affected knowledge of DS included quality of spoken English, knowing an affected child, parity and religion. The most significant factor affecting acceptance of screening was the woman's knowledge of DS. The source of information for the condition varied widely: 42% from a general practitioners (GP), 24% from the hospital and 16% from midwives. The proportion with good knowledge was similar in those women whose source of information was the GP (45%) and the midwife (41%). These proportions were, however, higher (though not significantly) when the source of information was from magazines and newspapers (67%) and from friends (53%). Uptake of the screening test was best in those with good knowledge (53%) compared to those with poor knowledge (23%) (p<0.02). Between 28% and 66% (depending on the ethnic group) of women had a screening blood test "allegedly" without knowing why it had been performed. In order to improve uptake of the screening test for DS there is need for better education and counselling of women attending for antenatal care.

Genetic distinctiveness of endangered dwarf blue sheep (Pseudois nayaur schaeferi): evidence from mitochondrial control region and Y-linked ZFY intron sequences

To elucidate the controversial systematic relationship of blue sheep (Pseudois nayaur) and endangered dwarf blue sheep, we sequenced part of the mtDNA control region and Y-linked ZFY intron, and carried out phylogenetic analyses. Mitochondrial results revealed that the dwarf blue sheep is a strongly supported monophyletic group, with an average of 12.21% sequence divergence from the blue sheep. This is the first genetic evidence for the distinctness of the dwarf blue sheep. ZFY intron results showed an average of 0.51% sequence divergence, and one shared haplotype between the dwarf blue sheep and blue sheep. By analyzing an expanded data set that incorporated ZFY intron sequences of two additional Ovis (sheep) species-O. nivicola and O. ammon--we demonstrated that ZFY intron provides good resolution at the species and genus levels. The ZFY intron sequence divergence between dwarf blue sheep and blue sheep was comparable to that within the two Ovis species. Moreover, we found intraspecific sequence variation in ZFY intron for all three species examined. We propose that dwarf blue sheep be designated as a subspecies of blue sheep, P. n. schaeferi.

How well do male latex condoms work? Pregnancy outcome during one menstrual cycle of use

To evaluate the contraceptive effectiveness of male latex condoms, we assembled a cohort of 300 women relying on male latex condoms for contraception and followed them prospectively for one menstrual cycle. None of the 234 women who completed the study and reported at least one act of intercourse conceived (one cycle pregnancy rate 0%; 95% CI 0%--2%). Given the pattern of intercourse during the cycle and 3 different sets of conception probabilities for different days of the cycle, we would have expected between 32 and 36 pregnancies if no condoms had been used. Thus, the prevented fraction due to condom use (effectiveness) is 100% and the lower bounds of the 95% CI are between 89% and 90%. For this cohort, male latex condoms were an effective method of contraception. This cost-efficient approach of evaluating contraceptive effectiveness shows promise for post-marketing studies.

Endometrial protection from tamoxifen-stimulated changes by a levonorgestrel-releasing intrauterine system: a randomised controlled trial

INTRODUCTION

Tamoxifen is currently the most commonly used adjuvant treatment for breast cancer, however, it frequently causes episodes of unscheduled uterine bleeding, which could be associated with proliferative changes of the endometrium, or even endometrial cancer. We aimed to assess whether a levonorgestrel intrauterine system could modulate the uterine responses to tamoxifen. We also aimed to assess women's tolerance of the screening procedures, the insertion, removal, and potential side-effects of the device.

METHODS

We did a randomised controlled trial, in which postmenopausal women who had had at least 1 year of adjuvant tamoxifen treatment and who were undergoing regular follow-up for breast cancer were randomly assigned to either endometrial surveillance alone, or endometrial surveillance before and after insertion of the levonorgestrel intrauterine system for 12 months. We assessed tolerance of the surveillance procedures and the device with visual analogue scales.

FINDINGS

Baseline assessment showed only benign uterine changes in all women (n=122). Hysteroscopic assessment indicated a uniform decidual response (confirmed histologically in 40 of 41 cases) in all women fitted with the intrauterine system; there were no new polyps in these women and 13% had fewer fibroids than in controls. Both screening procedures and device were well tolerated. There was an excess of bleeding in the women fitted with intrauterine systems but this resolved to a baseline similar to those receiving surveillance only.

INTERPRETATION

The levonorgestrel-releasing intrauterine system had a protective action against the uterine effects of tamoxifen. The effectiveness of this device in preventing uterine changes in the endometrium needs to be assessed in the context of decreasing the need for repeated investigations of postmenopausal bleeding in women taking tamoxifen.

Prostaglandin E(2)-dependent production of latent matrix metalloproteinase-9 in cultures of human fetal membranes

Studies in our laboratory have shown that structural changes in cervical biopsied fetal membranes, prior to labour, coincide with differences in the expression of the gelatinase enzyme, latent matrix metalloproteinase-9 (MMP-9). Concurrently, in vivo, there is an increase in the expression of prostaglandins, notably prostaglandin E(2) (PGE(2)), which has been shown to regulate the expression of MMPs in other systems. The aim of this study was to test the hypothesis (using an in-vitro culture model) that endogenously produced PGE(2) has a role in the elevation of MMP-9 described in vivo. Non-infected fetal membranes sampled from women undergoing elective Caesarean section were stimulated with 10% (v/v) fetal bovine serum (FBS), a known inducer of prostaglandins. This activation resulted in a time-dependent increase in the secretion of PGE(2) into the media, as determined by enzyme-linked immunosorbent assay (day 1: 19 +/- 9 pg/ml/24 h to 358 +/- 54 pg/ml/24 h by day 4). A similar pattern of secretion of latent MMP-9 was observed in parallel with the increase in PGE(2) in the same culture media (day 1: 1.63 +/- 0.17 ng/ml/24 h to 4.2 +/- 1.4 ng/ml/24 h by day 4). When both molecules were compared, a significant (P: < 0.01) positive correlation (r = 0.623) was observed. Secretion of the tissue inhibitor of MMPs-9 (TIMP-1) was not significantly different between untreated (3.07 +/- 0.266 microg/ml/24 h) and FBS-treated (3. 85 +/- 0.24 microg/ml/24 h) cultures during the first 4 days in culture. Prostaglandin synthesis inhibition studies using indomethacin (100 micromol/l) resulted in a 70-80% reduction in the activated secretion of latent MMP-9. Direct PGE(2) stimulation of cultures resulted in the bell shaped dose-response curve with concentrations of 1-100 nmol/l (which are within the range secreted in culture in response to FBS), stimulating significant latent MMP-9 secretion. These results suggest a link between endogenous PGE(2) and latent MMP-9 production in human fetal membranes, raising the possibility that PGE(2) has a role in the mechanism of fetal membrane structural changes and, hence, in parturition-associated membrane rupture.

Birth weight and 24-hour ambulatory blood pressure in nonproteinuric hypertensive pregnancy

OBJECTIVE

The aim of this study was to examine the relationship between maternal ambulatory blood pressure monitor measurements during pregnancy and birth weight in a population of women considered to have hypertension according to conventional antenatal clinic measurement.

STUDY DESIGN

A prospective observational study was carried out within the obstetric departments of Leicester Royal Infirmary and Queen Charlotte's Hospital. A total of 237 women were found to have hypertension (blood pressure >/=140/90 mm Hg) without significant proteinuria during examination in the antenatal assessment area. Sequential-day unit blood pressure recordings and a 24-hour automated ambulatory blood pressure recording were performed, and the results were compared with the principal outcome measure of birth weight.

RESULTS

A significant inverse association (gradient, -13.5; 95% confidence interval -23.4 to -3.6) was found between daytime ambulatory diastolic blood pressure measurement and birth weight. An increase of 5 mm Hg in daytime mean diastolic blood pressure was associated with a fall in birth weight of 68.5 g. This association remained after adjustment for potential confounders that included maternal age, maternal weight, smoking status, ethnicity, and gestational age at delivery. No such association was found between obstetric day unit assessment of blood pressure and birth weight.

CONCLUSION

There is a significant association between blood pressure and birth weight in nonproteinuric hypertensive pregnancies. The best predictor of this association is the daytime mean ambulatory diastolic blood pressure measurement. This is further evidence that maternal blood pressure may be an important confounding and potentially genetic variable in the association between birth weight and subsequent adult hypertension.

Antimicrobial-resistance trends in bacterial isolates from companion-animal community practice in the UK

We conducted a longitudinal, retrospective investigation of antimicrobial resistance in bacterial isolates obtained from canine and feline clinical cases in veterinary community practice in UK (1989-1997). Individual-drug resistance was examined using isolates of Escherichia coli and Staphylococcus spp. as Gram-negative and Gram-positive indicator organisms, respectively. The annual prevalence of resistance was calculated for each organism to each of nine (for E. coli) and 11 (for Staphylococcus spp.) selected antimicrobials. The annual prevalence of multiple-drug resistance (MDR) was calculated for E. coli, Proteus spp., Pseudomonas spp., staphylococci and streptococci. Using a chi-square test for trend, significant rising trends were identified in individual resistance of E. coli to clavulanate-amoxycillin and streptomycin, and in MDR of E. coli, Proteus spp. and Pseudomonas spp. Declining trends were identified in individual resistance of Staphylococcus spp. to ampicillin and penicillin. Comparison with previously reported results from a contemporaneous investigation of companion-animal hospital patients indicated that selection pressures acting on the two populations overlapped but were not identical.

Unilateral diaphragmatic paralysis following bronchial artery embolization for hemoptysis

Bronchial artery embolization is an effective treatment for patients with hemoptysis. Serious complications are rare, but may occur if the arterial supply to other structures is compromised. We present a case of unilateral diaphragmatic paralysis following bronchial artery embolization in a patient with cystic fibrosis. We believe that the diaphragmatic paralysis was due to the inadvertent obstruction of the left pericardiacophrenic artery during the embolization procedure, with compromise of the phrenic nerve blood supply. This resulted in a significant loss of lung function in our patient, who did not recover despite the subsequent return of diaphragmatic function.

Abnormal in vivo skeletal muscle energy metabolism in Huntington's disease and dentatorubropallidoluysian atrophy

We studied in vivo muscle energy metabolism in patients with Huntington's disease (HD) and dentatorubropallidoluysian atrophy (DRPLA) using 31P magnetic resonance spectroscopy (MRS). Twelve gene-positive HP patients (4 presymptomatic patients) and 2 gene-positive DRPLA patients (1 presymptomatic patient) were studied. 31P-MRS at rest showed a reduced phosphocreatine-to-inorganic phosphate ratio in the symptomatic HD patients and DRPLA patient. Muscle adenosine triphosphate/(phosphocreatine + inorganic phosphate) at rest was significantly reduced in both groups of symptomatic and presymptomatic HD subjects and was below the normal range in the 2 DRPLA subjects. During recovery from exercise, the maximum rate of mitochondrial adenosine triphosphate production was reduced by 44% in symptomatic HD patients and by 35% in presymptomatic HD carriers. The maximum rate of mitochondrial adenosine triphosphate production in muscle was also reduced by around 46% in the 2 DRPLA subjects. Our findings show that HD and DRPLA share a deficit of in vivo mitochondrial oxidative metabolism, supporting a role for mitochondrial dysfunction as a factor involved in the pathogenesis of these polyglutamine repeat-mediated neurodegenerative disorders. The identification of 31P-MRS abnormalities may offer a surrogate biochemical marker by which to study disease progression and the effects of treatment in HD and DRPLA.