A study of the prevalence of sexually transmitted infections and related conditions in pregnant women attending a sexual health service

A retrospective study was undertaken of all women attending a sexual health service during their pregnancies in the year 2000 in order to find the prevalence of sexually transmitted infections (STIs) and other conditions commonly screened for in sexual health services among this population. Data relating to demographics, sexual health screen and infections diagnosed were collected. All new female registrations during the same period were additionally identified. The prevalence of disease in the two groups was compared. Data on 164 patients who attended during their pregnancies in the year 2000 were analysed. One STI was identified in 59 patients (36%), two infections in nine patients (5%) and three infections in three patients (2%). An increased prevalence of STIs was noted in those aged 25 and under, compared with those over 25 ( P <0.001). Prevalence of STIs increased with gestation (0.01 < P>0.05). Prevalence of STIs was higher in pregnant women (63/164; 38.4%) compared with all new female registrations (1094/5273; 20.7%; P <0.001) during the same period. Additionally, 8.5% of pregnant women had a negative screen compared with 20% of all new female cases. This study shows the prevalence of STIs to be significantly higher among the pregnant women as compared with all women attending. A trend towards more frequent occurrence of an STI was seen with increasing gestation and young age. Prospective studies are needed to verify these results among an unselected population of pregnant women.

Similarities in Test Scores and Profiles of Kibbutz Twins and Singletons

Resemblances on five cognitive tests were compared in fifty quartets of school children. Each quartet consisted of a twin pair (MZ or DZ) and a matched singleton pair from the same kibbutz peer group. Similarities of MZs and DZs on test scores essentially replicate those reported previously in other studies. The median correlation for singleton control pairs is 0.29, as compared with that of 0.26 reported in the Texas Adoption Study for unrelated children raised in the same home. In the two spatial tests, control pairs were as similar as the DZ pairs. This suggests a more powerful influence on shared environment in aspects of perceptual performance. A new structural analysis (POSAC) of individual profiles of test scores is presented. Comparison of space diagrams of MZ, DZ, and singleton pair profiles shows systematic differences in structure among the three groups, in accordance with the predicted levels of genetic influences. Such structural differences transcend mere differences in size of correlation, and may give more stringent evidence for the respective roles of genetics and environment.

The role of functional dopamine-transporter SPECT imaging in parkinsonian syndromes, part 2

SUMMARY

The functional imaging technique most widely used in European clinics to differentiate a true parkinsonian syndrome from vascular parkinsonism, drug-induced changes, or essential tremor is dopamine-transporter SPECT. This technique commonly reports dopamine-transporter function, with decreasing striatal uptake demonstrating increasingly severe disease. The strength of dopamine-transporter SPECT is that nigrostriatal degeneration is observed in both clinically inconclusive parkinsonism and early, even premotor, disease. In this clinical review (Part 2), we present the dopamine-transporter SPECT findings in a variety of neurodegenerative diseases, including multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, and dementia with Lewy bodies. The findings in vascular parkinsonism, drug-induced parkinsonism, and essential tremor are also described. It is hoped that this technique will be the forerunner of a range of routinely used, process-specific ligands that can identify early degenerative disease and subsequently guide disease-modifying interventions.

The role of functional dopamine-transporter SPECT imaging in parkinsonian syndromes, part 1

SUMMARY

As we defeat infectious diseases and cancer, one of the greatest medical challenges facing us in the mid-21st century will be the increasing prevalence of degenerative disease. Those diseases, which affect movement and cognition, can be the most debilitating. Dysfunction of the extrapyramidal system results in increasing motor disability often manifest as tremor, bradykinesia, and rigidity. The common pathologic pathway of these diseases, collectively described as parkinsonian syndromes, such as Parkinson disease, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, and dementia with Lewy bodies, is degeneration of the presynaptic dopaminergic pathways in the basal ganglia. Conventional MR imaging is insensitive, especially in early disease, so functional imaging has become the primary method used to differentiate a true parkinsonian syndrome from vascular parkinsonism, drug-induced changes, or essential tremor. Unusually for a modern functional imaging technique, the method most widely used in European clinics depends on SPECT and not PET. This SPECT technique (described in the first of 2 parts) commonly reports dopamine-transporter function, with decreasing striatal uptake demonstrating increasingly severe disease.

Genetic and environmental influences on pupil performances

The results presented in this paper are part of a current comparative study of genetic and environmental influences in three educational settings: Stockholm, Jerusalem and the Israeli kibbutz. We specifically wanted to investigate whether a more restrictive educational setting would decrease genetic influences. Here we report on comparisons of cognitive performance measures at several time points for twins/controls, boys/girls and within-pair similarity in MZ, DZ and controls. The tests used were the Raven Progressive Matrices, verbal, reading comprehension and arithmetic. The results show no differences between twins and controls, whilst gender differences seem to be smallest in the Stockholm sample and largest in Jerusalem. A pattern of genetic influences on cognitive performance was also clearly visible in Jerusalem. In Stockholm shared environmental influences at home and at school seemed even stronger than in the kibbutz. No consistent differences were found between tests or occasions.

The impact of genital warts: loss of quality of life and cost of treatment in eight sexual health clinics in the UK

OBJECTIVES

To estimate the loss of quality of life and cost of treatment associated with genital warts seen in sexual health clinics.

METHODS

A cross-sectional questionnaire study and case note review of individuals with genital warts, carried out in eight sexual health clinics in England and Northern Ireland. Individuals with genital warts attending the participating clinics were invited to take part in the questionnaire study. 895 participants were recruited. A separate sample of 370 participants who had attended a participating clinic with a first visit for a first or recurrent episode of genital warts between April and June 2007 was included in the case note review. Quality of life was measured using the EQ-5D questionnaire and the cost of an episode of care was derived from the case note review.

RESULTS

The weighted mean EQ-5D index score was 0.87 (95% CI 0.85 to 0.89). The weighted mean disutility was 0.056 (95% CI 0.038 to 0.074). The estimated mean loss of quality-adjusted life-years associated with an episode of genital warts was 0.018 (95% CI 0.0079 to 0.031), equivalent to 6.6&emsp14;days of healthy life lost per episode. The weighted mean cost per episode of care was £94 (95% CI £84 to £104), not including the cost of a sexually transmitted infection screen.

CONCLUSIONS

Genital warts have a substantial impact on the health service and the individual. This information can be utilised for economic evaluation of human papillomavirus vaccination.

Retrospective, observational data collection of the treatment of phenylketonuria in the UK, and associated clinical and health outcomes

OBJECTIVE

To determine the percentage of phenylketonuria (PKU) subjects using current treatment strategies whose phenylalanine (Phe) concentrations diverge from the UK target guidelines for PKU.

RESEARCH DESIGN AND METHODS

This retrospective, observational, chart review was conducted between 2004 and 2008 at three specialist PKU treatment centres in the UK, and included 125 eligible subjects: 20 adults (18+ years, with ≥4 Phe concentrations measured per year) and 105 children (up to age 17, with ≥6 Phe concentrations measured per year).

RESULTS

The mean percentage of subjects with at least 70% of Phe concentrations within the target range for 0-5-year olds, 6-10 year olds and 11-17 year olds was similar across the period 2004-2008 (57.0%, 56.5% and 57.1%, respectively) and lower (39.4%) in the 18+ year age group. For all ages, across the period the mean was 54.4%. Further analysis of the adult population showed that some subjects were very good at complying with treatment and reporting Phe concentrations. Overall, the percentage of 100% compliance was 15.7% in females and 13.7% in males. The mean duration that subjects were 'out of range' of target Phe concentrations over the study period was approximately 1 year and 3 months and the mean duration for 'significantly out of range' values was approximately 9 months. The most common type of contact made with subjects was by telephone, with a mean number of 16 calls per subject per year.

CONCLUSION

The results support current literature showing that a proportion of subjects with PKU, in particular older subjects, are not fully compliant with their treatment and subsequently have Phe concentrations that depart from national recommendations. However, definitive conclusions may not be drawn due to the retrospective nature of the study and the small number of observed subjects.

Recent Advances in Three Dimensional Thin Film Microbatteries

Autonomous MEMS require similarly miniaturized power sources. We present the first three-dimensional (3D) working thin-film microbattery (MB) technology that is compatible with MEMS requirements. Our 3D MBs are formed in perforated substrates (silicon chip or glass microchannel plate), in which a sandwich-like thin-film battery structure is deposited conformally and sequentially on all available surfaces, using wet chemistry. The area of high aspect ratio holes in the substrate enhances the capacity and energy density per given substrate footprint by more than an order of magnitude. Full 3D cells were manufactured on both glass and silicon substrates. A 3D cell on a micro-channel plate substrate exhibited a capacity of ca. 2mAh/cm2, in good agreement with the ca. 23 times area gain provided vs an identical footprint 2D cell.

More than a decade on: review of the use of imiquimod in lower anogenital intraepithelial neoplasia

To assess the effectiveness of 5% imiquimod cream (IQ) in the treatment of vulvar, penile and anal intraepithelial neoplasias (VIN, PIN and AIN), we searched Medline, Embase, PubMed and Cochrane Library databases. With regard to VIN there were two randomized controlled trials (RCTs), eight uncontrolled/cohort studies, nine case reports and one review article. Use of IQ in PIN and AIN were only supported by cohort studies (two each for PIN and AIN) and case reports (15 for PIN and 3 for AIN). On pooled analysis of RCTs, uncontrolled and cohort studies, the mean complete response (CR) rate for VIN, PIN and AIN were 51%, 70% and 48%, respectively. The mean partial response (PR) rate for VIN, PIN and AIN were 25%, 30% and 34% respectively. The recurrence (RR) rate for VIN, PIN and AIN were 16%, 0% and 36%, respectively. The follow-up period for VIN, PIN and AIN ranged from 2 to 32 months, 10 to 12 months and 11 to 39 months, respectively. Although the results for PIN look the best, the strongest evidence regarding efficacy of IQ in anogenital intraepithelial neoplasia is for VIN supported by RCTs. Evidence for use of IQ in AIN was essentially limited to HIV-positive men who have sex with men. IQ was reasonably well tolerated with side-effects being managed with reduction in frequency of drug usage and/or rest periods. Based on these results, IQ seems to be a safe mode of treatment and is possibly an alternative to currently available methods of treatment. However, there are no comparative studies assessing its efficacy against traditional modes of treatment.

Treatment of anal human papillomavirus-associated disease: a long term outcome study

Summary

Treatment for human papillomavirus (HPV)-associated anal canal disease has been unsatisfactory. The objective of our study was to determine the treatment outcome in our cohort with anal HPV disease. Overall, 181 patients were evaluated over a median period of 19.1 months (range = 2.8–125.5). Eighty-eight patients (48.6%) with high-grade anal intraepithelial neoplasia (AIN) and 82 patients (45.3%) with low-grade AIN underwent treatment. One hundred and forty-one patients (77.9%) received laser ablative treatment as an outpatient procedure. The treatment yielded cure, defined as a disease-free state at 12 months after treatment, in 63.0% (114/181). Median time to cure for the cohort was 31.5 months (95% confidence interval: 23.0–40.0). Treatment outcome showed no evidence of being affected by age, sexual preference, history of smoking or presence of high-grade disease. Median time to cure was significantly affected by a positive HIV status ( P = 0.02) and the extent (volume) of the disease ( P = 0.01). Contrary to the current view that treatment of HPV-related anal disease is difficult, unrewarding due to recurrences and may lead to substantial morbidity, we demonstrate that effective treatment is possible for both low- and high-grade AIN. These findings should help with the general desire to introduce screening for AIN for at-risk groups.

The significance of Epstein-Barr virus detected in the cerebrospinal fluid of people with HIV infection

INTRODUCTION

Epstein-Barr virus (EBV) is detected in the cerebrospinal fluid (CSF) in people with HIV infection who develop primary cerebral lymphoma (PCL). However, EBV may also be detected in the CSF of patients without PCL, and here the significance is uncertain.

METHODS

Ninety-eight HIV-positive patients had lumbar punctures performed and polymerase chain reaction (PCR) for EBV was undertaken on the CSF. Thirty-eight patients had non-Hodgkin's lymphoma (NHL), including four with PCL. Sixty patients had a CSF examination for other indications. The clinicopathological details, symptoms, diagnosis, CSF and neuroimaging findings and therapy at time of CSF were recorded and correlated with CSF EBV PCR results.

RESULTS

EBV was detected in the CSF in three of four patients (75%) with PCL, one of three (33%) with systemic lymphoma and meningeal involvement, and four of 31 (13%) with systemic lymphoma and no meningeal disease. Seven of 60 patients (12%) without lymphoma were CSF EBV-positive. There were no differences in immunological, clinical, biochemical or radiological parameters between patients with and without EBV in the CSF. After a median follow-up time of 30 weeks (maximum 102 weeks), none of the seven CSF EBV-positive patients has developed PCL.

CONCLUSION

EBV was detected in up to 12% of patients with neurological symptoms but without lymphoma. A positive result did not correlate with more advanced immunosuppression or a particular neurological diagnosis. Patients with EBV in their CSF did not appear to be at increased risk of developing PCL in the short term.

Anomalous left coronary artery from aorta with Prinzmetal's angina: a postoperative dilemma successfully managed

Anomalous aortic origin of one of the coronary arteries is uncommon. There have been few reports of the left coronary artery arising from the noncoronary sinus. The occurrence of Prinzmetal's angina in association with anomalous aortic origin is extremely rare. We report a case of such a combination and discuss the diagnostic options and therapeutic decision making.

Internal medicine residents' perceptions of cross-cultural training. Barriers, needs, and educational recommendations

BACKGROUND

Physicians increasingly face the challenge of managing clinical encounters with patients from a range of cultural backgrounds. Despite widespread interest in cross-cultural care, little is known about resident physicians' perceptions of what will best enable them to provide quality care to diverse patient populations.

OBJECTIVES

To assess medicine residents' (1) perceptions of cross-cultural care, (2) barriers to care, and (3) training experiences and recommendations.

DESIGN, SETTING, AND PATIENTS

Qualitative individual interviews were conducted with 26 third-year medicine residents at Massachusetts General Hospital in Boston (response rate=87%). Interviews were recorded, transcribed, and analyzed.

RESULTS

Despite significant interest in cross-cultural care, almost all of the residents reported very little training during residency. Most had gained cross-cultural skills through informal learning. A few were skeptical about formal training, and some expressed concern that it is impossible to understand every culture. Challenges to the delivery of cross-cultural care included managing patients with limited English proficiency, who involve family in critical decision making, and who have beliefs about disease that vary from the biomedical model. Residents cited many implications to these barriers, ranging from negatively impacting the patient-physician relationship to compromised care. Training recommendations included making changes to the educational climate and informal and formal training mechanisms.

CONCLUSIONS

If cross-cultural education is to be successful, it must take into account residents' perspectives and be focused on overcoming residents' cited barriers. It is important to convey that cross-cultural education is a set of skills that can be taught and applied, in a time-efficient manner, rather than requiring an insurmountable knowledge base.

A year of mentoring in academic medicine: case report and qualitative analysis of fifteen hours of meetings between a junior and senior faculty member

We describe a specific mentoring approach in an academic general internal medicine setting by audiotaping and transcribing all mentoring sessions in the year. In advance, the mentor recorded his model. During the year, the mentee kept a process journal. Qualitative analysis revealed development of an intimate relationship based on empathy, trust, and honesty. The mentor's model was explicitly intended to develop independence, initiative, improved thinking, skills, and self-reflection. The mentor's methods included extensive and varied use of questioning, active listening, standard setting, and frequent feedback. During the mentoring, the mentee evolved as a teacher, enhanced the creativity in his teaching, and matured as a person. Specific accomplishments included a national workshop on professional writing, an innovative approach to inpatient attending, a new teaching skills curriculum for a residency program, and this study. A mentoring model stressing safety, intimacy, honesty, setting of high standards, praxis, and detailed planning and feedback was associated with mentee excitement, personal and professional growth and development, concrete accomplishments, and a commitment to teaching.

Panic probes and the identification of panic: a historical and cross-cultural perspective

This article reviews the historical development of the category of panic disorder in the United States, particularly the shifting perspectives on both what causes panic and how the presence of panic should be determined. The notion that panic attacks of a panic-disorder type must be "out of the blue" and "unexpected," except in the case of triggering by a particular place (i.e., agoraphobia), is critiqued. The authors illustrate that a meaningful epidemiological determination of panic rates in other cultural groups must be preceded by a detailed ethnography that ascertains the catastrophic cognitions, core symptoms, and typical cues of panic attacks in that particular context.

Drug use among the urban poor in Kolkata: behaviour and environment correlates of low HIV infection

BACKGROUND

HIV infection in injecting drug users (IDUs) has worked as a driving force for further spread of the virus in other population groups. Major metropolitan cities such as Mumbai, Kolkota, Chennai and Delhi have seen a diffusion of injecting drug use within the last decade. The prevalence of HIV infection among injectors ranges from 2% to 30%. Identifying effective interventional elements that have kept the prevalence of HIV low for the past 7 years among IDUs of Kolkata is thus of public health importance.

METHODS

A purposive sample of opioid/opiate users was studied. Primary and secondary data on drug users, law-enforcement environment, records at drug treatment centres, jail admission data related to the 'Narcotic Drug and Psychotropic Substance Act' and interventions in other risk groups were collected. Laboratory tests for HIV, hepatitis B surface antigen and syphilis were done on consenting IDUs (n=129) and non-IDUs (n=120). For univariate and multivariate analysis, IDUs were taken as cases and non-IDUs as controls.

RESULT

Of the IDUs, 2% were positive for HIV. No non-IDU was HIV-positive. Significantly more non-IDUs (10% v. 4%, p=0.05) were positive for syphilis. Sharing injection equipment within the past 6 months was reported by 71% of IDUs; sharing partners were stable and ranged from 1 to 3. More IDUs compared to non-IDUs reported being in touch with intervention programmes. The police has been tolerant to needle-syringe exchange and oral sublingual buprenorphine substitution conducted in Kolkata. Unlike in the early 1990s, non-IDUs did not switch to injecting during non-availability of brown sugar in the latter half of the 1990s and instead sought tratment. The availability of high quality heroin (>20%-50%) was low and the proportion of moderate quality heroin (>10%-20%) went up during these times due to increased police seizures. No intervention exists in jails despite the fact that a large number of drug users spend time in jail.

CONCLUSION

Stable and few injection equipment-sharing partners of IDUs, launching of early targeted interventions among IDUs and sex workers in the city, police tolerance to harm reduction activities and preference of non-IDUs for detoxification during heroin draught periods have kept HIV prevalence at a low level among drug users of Kolkata for the past 7 years. immediate launching of interventions for drug users in jails seems necessary. Similar multi-pronged strategies with targeted and environmental intervention could work in other settings as well.

Imiquimod 5% cream is an acceptable treatment option for external anogenital warts in uncircumcised males

OBJECTIVES

To determine the safety and efficacy of imiquimod (Aldara) 5% cream in the treatment of prepuce-associated warts in uncircumcised males.

METHODS

An open-label study in six UK medical centres with 35 uncircumcised males with prepuce-associated warts treated with imiquimod 5% cream three times per week for up to 16 weeks. Other anogenital warts were also treated.

RESULTS

Three times weekly application of imiquimod was found to be safe, with erythema as the most commonly reported local skin reaction. Forty per cent of patients had complete clearance of anogenital warts within 16 weeks.

CONCLUSIONS

Imiquimod cream at a dosing regimen of three times per week, is effective and has an acceptable safety profile in the treatment of prepuce associated warts and other external anogenital warts in uncircumcised males.

A case of fatal tumor embolus following trauma in a patient with undiagnosed Wilms' tumor

Involvement of the inferior vena cava with tumor thrombus has been reported in 5 to 10% of patients with Wilms' tumor. Preoperative imaging usually alerts the surgeon to the extent of the intravascular extension. We present a case report of trauma to a previously undiagnosed Wilms' tumor that resulted in a fatal intraoperative pulmonary tumor embolus.

Transmyocardial laser revascularization

Low-powered lasers were first used in the early 1980s to produce transventricular channels as an adjunct to coronary artery bypass graft surgery (CABG). Early results were encouraging, but because of the combined procedure, could not be attributed directly to use of the laser [1]. High-powered lasers were introduced into clinical practice in 1990 [2]. These lasers are powerful enough to create a transmyocardial channel with minimal thermal damage to surrounding tissues [3]. Clinical studies, using transmyocardial laser revascularization (TMR) as the sole operative therapy for patients with severe and diffuse coronary artery disease (CAD) who have Class III or IV angina, and are on medical therapy, have been conducted since 1993. Based on the results of these studies, the FDA granted approval for the use of TMR as a sole therapy. Clinical studies are currently underway to assess the results of combined TMR and CABG [4]. Results of four controlled randomized studies have been published [5-8]. The data from two of these studies formed the basis for FDA approval of two different types of laser systems. The results of these studies have not provided any additional insights into the mechanism of action of TMR, which remains the Achilles' heel of this procedure. In this review, background information about the TMR procedure will be discussed along with an analysis of the recently published randomized studies.

Has laser revascularization found its place yet?

Transmyocardial laser revascularization (TMR) is a relatively new therapy for atherosclerotic coronary artery disease. Unlike well established surgical and percutaneous revascularization procedures, TMR is reserved for patients with advanced and severe forms of coronary artery disease that is unsuitable for other forms of revascularization. The results of TMR so far have been controversial with a bias toward steady and incremental adoption as sole therapy or in combination with coronary artery bypass graft surgery. The controversy surrounding TMR is related to the fact that its mechanism of action is not proven beyond a reasonable doubt. It is believed that angiogensis stimulation by the laser beam may be responsible for the relief of angina. However, the marked discrepancy in the symptomatic relief of angina and the increase in myocardial perfusion is not well understood. Other mechanisms proposed include direct perfusion through the laser channels, myocardial damage, denervation of ischemic myocardium and a placebo effect. It is possible that one or more of these mechanism may be responsible at various time intervals for the relief of angina. The challenge of TMR is related to improvement in perioperative outcomes, and long-term survival without worsening of left ventricular function. The achievement of these goals makes TMR an alternative therapy to what was formerly the only therapeutic option for these patients, namely: failed maximum medical therapy.

Enhanced uptake of 99Tcm-MDP in skeletal metastases from prostate cancer following initiation of hormone treatment: potential for increasing delivery of therapeutic agents

Following androgen ablation therapy, skeletal metastases from prostate cancer appear in some instances to show an increase in 99Tcm-methylene diphosphonate (99Tcm-MDP) uptake. Such a phenomenon could represent a mechanism to increase delivery of bone-seeking therapeutic agents to skeletal metastatic sites. The aim of this study was to characterize more precisely the potential increase in 99Tcm-MDP in skeletal metastases from prostate cancer following initiation of hormone therapy. Baseline bone scans were performed within 1 week of onset of hormone therapy in patients with stage D2 prostate cancer followed by multiple repeat bone scans for up to 4-6 weeks. The count density within metastatic lesions was divided by the average count density from several areas of normal bone to obtain a lesion to normal bone uptake ratio (L/N) for each lesion in each scan. Altogether, 61 skeletal metastases were identified on bone scans from five subjects. Eighty-four percent (51/61) of these lesions showed an increase in 99Tcm-MDP activity relative to normal bone following initiation of hormone therapy with a mean peak increase of 39%. Thirty-nine of these 51 metastatic lesions showed maximum uptake at 3 weeks post-onset of hormone treatment. From our findings, it appears that approximately 3 weeks following initiation of hormone blockade, most skeletal metastases from prostate cancer will demonstrate significantly enhanced 99Tcm uptake relative to normal bone. Consequently, it may be possible to improve the uptake and effectiveness of therapeutic bone-seeking radiopharmaceuticals by administering these agents following hormone therapy in patients with prostate cancer metastases.

Genetic and environmental influences on pupil performances

The results presented in this paper are part of a current comparative study of genetic and environmental influences in three educational settings: Stockholm, Jerusalem and the Israeli kibbutz. We specifically wanted to investigate whether a more restrictive educational setting would decrease genetic influences. Here we report on comparisons of cognitive performance measures at several time points for twins/controls, boys/girls and within-pair similarity in MZ, DZ and controls. The tests used were the Raven Progressive Matrices, verbal, reading comprehension and arithmetic. The results show no differences between twins and controls, whilst gender differences seem to be smallest in the Stockholm sample and largest in Jerusalem. A pattern of genetic influences on cognitive performance was also clearly visible in Jerusalem. In Stockholm shared environmental influences at home and at school seemed even stronger than in the kibbutz. No consistent differences were found between tests or occasions.

Height change caused by creep in intervertebral discs: a sagittal plane model

Changes in spinal column height have been observed in response to different stress environments including vibration, gravity inversion, space flight, traction, and increased loading. Alterations in spinal height are dependent on body forces, externally applied forces, and properties of the discs and are considered relevant to understanding the normal and pathologic behavior of the spine. This study presents a sagittal plane, viscoelastic model of the spine that quantified the height change behavior of the human spine subjected to axial compressive forces similar to those experienced during quiet standing. The two-dimensional spine model was idealized as a collection of 23 rigid vertebral bodies and 23 deformable intervertebral discs. Time-dependent height losses were modeled using axial compressive creep material properties based on in vitro measurements obtained from the literature. The model demonstrated an instantaneous loss in height of 11.7 mm (0.67% of body height) and a height loss of 19.6 mm (1.1% of body height) at the end of 8 h. Changes in sagittal profile were estimated to contribute to 12% of the overall height loss after 8 hours. Discs in the lumbar region lost the most height, but the contribution of the lumbar region to the total height loss was 32%. The height loss contribution of the thoracic region was higher (57%), presumably because of the increased number of discs contributing to the total height loss in this region. For degenerated discs, the model predicted a similar instantaneous height loss but a 28% greater height loss after 8 h. These results suggest that the majority of spinal height loss is a direct result of intervertebral disc deformation and about two thirds of the total height loss occurs immediately on axial loading of the spine. Based on these findings, diurnal height changes in the spine are predicted to be much greater than previously believed.

Airway smooth muscle, tidal stretches, and dynamically determined contractile states

In the classic theory of airway lumen narrowing in asthma, active force in airway smooth muscle is presumed to be in static mechanical equilibrium with the external load against which the muscle has shortened. This theory is useful because it identifies the static equilibrium length toward which activated airway smooth muscle would tend if given enough time. The corresponding state toward which myosin-actin interactions would tend is called the latch state. But are the concepts of a static mechanical equilibrium and the latch state applicable in the setting of tidal loading, as occurs during breathing? To address this question, we have studied isolated, maximally contracted bovine tracheal smooth muscle subjected to tidal stretches imposed at 0.33 Hz. We measured the active force (F) and stiffness (E), which reflect numbers of actin-myosin interactions, and hysteresivity (eta) which reflects the rate of turnover of those interactions. When the amplitude of imposed tidal stretch (epsilon) was very small, 0.25% of muscle optimal length, the steady-state value of F approximated the isometric force, E was large, and eta was small. When epsilon was increased beyond 1%, however, F and E promptly decreased and eta promptly increased. The muscle could be maintained in these steady, dynamically determined contractile states for as long as the tidal stretches were sustained; when epsilon subsequently decreased back to 0.25%, F, E, and eta returned slowly toward their previous values. The provocative stretch amplitude required to cause active force or muscle stiffness to fall by half, or hysteresivity to double, was slightly greater than 2%. These observations are consistent with a direct effect of stretch upon bridge dynamics in which, with increasing tidal stretch amplitude, the number of actin-myosin interactions decreases and their rate of turnover increases. We conclude that the interactions of myosin with actin are at every instant tending toward those that would prevail in the isometric steady state, but tidal changes of muscle length cause an excess in the rate of detachment. These stretch-induced detachment events can come so fast compared with the rate of attachment that static equilibrium conditions are never attained. If so, then airway lumenal narrowing and the underlying contractile state would be governed by a dynamic mechanical process rather than by a mechanical equilibrium of static forces.

Antivasoconstrictor and antiaggregatory activities of picotamide unrelated to thromboxane A2 antagonism

Picotamide is a dual thromboxane (Tx) A2 receptor antagonist/Tx synthase inhibitor although some observations suggest an anti-vasoconstrictor effect independent of TxA2 inhibition/antagonism. The aim of our study was to assess whether picotamide antagonises vascular contractions induced by different vasoactive substances in vitro. Picotamide inhibited competitively the contraction of rabbit aortic rings induced by the TxA2 mimetic U46619 (pA2 = 3.59) but also the contractions induced by phenylephrine (pA2 = 3.93) and serotonin (5-HT) (pA2 = 5.81) although in a not competitive way. Picotamide did not inhibit potassium-induced contractions, thus excluding aspecific effects on vascular smooth muscle. Picotamide inhibited 5-HT-induced platelet aggregation in vitro with an IC50 (212 microM) similar to that found when other aggregating stimuli are used, but it did not affect shape change (IC50 > 1 mM) suggesting that the effects of picotamide can not be ascribed to 5-HT2-receptor antagonism; in the same experimental conditions neither a Tx-receptor antagonist (BM13.177) nor a dual Tx-receptor antagonist/synthase inhibitor (ridogrel) affected 5-HT-induced platelet responses. Our studies demonstrate that picotamide exerts antivasoconstrictor and platelet inhibitory effects unrelated to TxA2 antagonism. This activity may contribute to the anti-thrombotic/anti-ischaemic effects of the drug in vivo.

Reverse transcriptase. The use of cloned Moloney murine leukemia virus reverse transcriptase to synthesize DNA from RNA

Reverse transcriptase (RT) is the key enzyme required for conversion of RNA to DNA. Cloning of Moloney murine leukemia virus (MMLV) RT has enable engineering an RT that lacks endogenous RNase H activity. RT catalyzes cDNA synthesis more efficiently in the absence of RNase H. We describe here a number of properties of MMLV RT and RNase H-minus MMLV RT not summarized in a single location elsewhere, providing a basis for best use of these enzymes in cDNA synthesis. In addition, general guidelines and detailed protocols are provided for use of MMLV RTs in one tube double-stranded cDNA synthesis, in [32P]cDNA synthesis, and in RT-PCR and long RT-PCR.

Friction in airway smooth muscle: mechanism, latch, and implications in asthma

In muscle, active force and stiffness reflect numbers of actin-myosin interactions and shortening velocity reflects their turnover rates, but the molecular basis of mechanical friction is somewhat less clear. To better characterize molecular mechanisms that govern mechanical friction, we measured the rate of mechanical energy dissipation and the rate of actomyosin ATP utilization simultaneously in activated canine airway smooth muscle subjected to small periodic stretches as occur in breathing. The amplitude of the frictional stress is proportional to eta E, where E is the tissue stiffness defined by the slope of the resulting force vs. displacement loop and eta is the hysteresivity defined by the fatness of that loop. From contractile stimulus onset, the time course of frictional stress amplitude followed a biphasic pattern that tracked that of the rate of actomyosin ATP consumption. The time course of hysteresivity, however, followed a different biphasic pattern that tracked that of shortening velocity. Taken together with an analysis of mechanical energy storage and dissipation in the cross-bridge cycle, these results indicate, first, that like shortening velocity and the rate of actomyosin ATP utilization, mechanical friction in airway smooth muscle is also governed by the rate of cross-bridge cycling; second, that changes in cycling rate associated with conversion of rapidly cycling cross bridges to slowly cycling latch bridges can be assessed from changes of hysteresivity of the force vs. displacement loop; and third, that steady-state force maintenance (latch) is a low-friction contractile state. This last finding may account for the unique inability of asthmatic patients to reverse spontaneous airways obstruction with a deep inspiration.

Elements within the beta-lactoglobulin gene inhibit expression of human serum albumin cDNA and minigenes in transfected cells but rescue their expression in the mammary gland of transgenic mice

Two new beta-lactoglobulin (BLG)/human serum albumin (HSA) hybrid gene vectors were constructed and tested for expression in COS-7 cells and in transgenic mice. The HSA sequences were inserted between the second and sixth BLG exons. Transient transfection experiments with these vectors as well as a series of additional vectors with either the BLG 5'- or 3'- intragenic sequences revealed that sequences within BLG exon 1/intron 1/exon 2 abrogated BLG- directed HSA expression in vitro, regardless of the presence of HSA introns or the origin of the 3' polyadenylation signal. In contrast, the same BLG expression cassette enabled the efficient expression of HSA cDNA or minigene in the mammary gland of transgenic mice with subsequent secretion of the corresponding protein into the milk of 56 and 82%, respectively of the mouse strains at levels up to 0.3 mg/ml. Previous attempts to express HSA cDNA inserted into exon 1 of the BLG gene had failed [Shani,M., Barash,I., Nathan,M., Ricca,G., Searfoss,G.H., Dekel,I., Faerman,A., Givol,D. and Hurwitz,D.R. (1992) Transgenic Res. 1, 195- 208]. The new BLG expression cassette conferred more stringent tissue specific expression than previously described BLG/HSA constructs [Barash,I, Faerman,A., Ratovitsky,T, Puzis,R., Nathan,M., Hurwitz,D.R. and Shani, M. (1994) Transgenic Res. 3, 141-151]. However, it was not able to insulate the transgenes from the surrounding host DNA sequences and did not result in copy number dependent expression in transgenics. Together, the in vitro and in vivo results suggest both positive and negative regulatory elements within the BLG intragenic sequences evaluated. The new BLG construct represents an extremely valuable vector for the efficient expression of cDNAs in the mammary gland of transgenic animals.

Dramatic heterogeneity of transgene expression in the mammary gland of lactating mice: a model system to study the synthetic activity of mammary epithelial cells

We studied the expression of human serum albumin (HSA) driven by the ovine beta-lactoglobulin promoter in the mammary glands of lactating mice from five independent transgenic strains, by employing combined in situ hybridization and immunostaining techniques. Four strains displayed a heterogeneous pattern of expression: mice of strains 91 and 92 expressed the transgene in only a fraction of the lobules, whereas in strains 69 and 83 all lobules contained cells expressing HSA. In all four strains the patterns of expression within expressing lobules corresponded to the morphology of alveolar cells and to the extent of local milk secretion, suggesting that filling of alveolus with secreted material was accompanied by asynchronous downregulation of transgene expression. In situ hybridization to the endogenous milk protein genes alpha-lactalbumin, beta-casein, and whey acidic protein revealed a uniform pattern of expression in lactating mammary glands of transgeneic and in four out of five non-transgeneic mice. In the fifth control mouse, we detected downregulation of gene expression in lobules containing alveoli distended by secreted milk. The pattern of expression of the three endogenous genes was greatly disturbed after a short (3-hr) unilateral closure of mammary glands, and very much resembled the pattern of expression of the HSA transgenes. These results demonstrate that transgeneic mice provide a useful model to study the factors that regulate the synthetic activity of mammary epithelial cells.

Reanalysis of SCOR and anxiety measures in the Israeli High-Risk Study

In an earlier study, skin conductance orienting response (SCOR) and anxiety measures obtained when the subjects of the Israeli High-Risk Study were 11 years old were analyzed, using adult diagnostic information, when the subjects were 26 years old. The present study considers similar data obtained from most of this sample when the subjects were 16 years old. As in the earlier analysis, those subjects who would receive a schizophrenia spectrum diagnosis at 26 had higher anxiety ratings at age 16. Nondiagnosed index subjects also had significantly higher anxiety ratings than the nondiagnosed controls. The subjects who would receive affective spectrum diagnoses at age 26 had the most hyporesponsive SCORs, as predicted, while the subjects who would later be diagnosed in the schizophrenia spectrum had an unexpected hyperresponsive SCOR to the dishabituation tone in a habituation series. Further consideration of the long-term stability of SCORs seems necessary; they may be related to the developing psychopathological processes.