A scalable cryogenic LED module for selectively illuminating kinetic inductance detector arrays

We present the design and measured performance of a light emitting diode (LED) module for spatially mapping kinetic inductance detector (KID) arrays in the laboratory. Our novel approach uses a multiplexing scheme that only requires seven wires to control 480 red LEDs, and the number of LEDs can be scaled up without adding any additional wires. This multiplexing approach relies on active surface mount components that can operate at cryogenic temperatures down to 10 K. Cryogenic tests in liquid nitrogen and inside our cryostat demonstrate that the multiplexer circuit works at 77 and 10 K, respectively. The LED module presented here is tailored for our millimeter-wave detector modules, but the approach could be adapted for use with other KID-based detector systems.

Irradiation Issues and Material Selection for Canadian SCWR Components

The Canadian super critical water-cooled reactor (SCWR) concept requires materials to operate at higher temperatures than current generation III water-cooled reactors. Materials performance after radiation damage is an important design consideration. Materials that are both corrosion resistant and radiation damage tolerant are required. This paper summarizes the operating conditions including temperature, neutron flux, and residence time of in-core Canadian SCWR components. The focus is on the effects of irradiation on in-core components, including those exposed to a high neutron flux in the fuel assembly, the high pressure boundary between coolant and moderator, as well as the low-temperature, low-flux calandria vessel that contains the moderator. Although the extreme conditions and the broad range of SCWR in-core operating conditions present significant materials selection challenges, candidate alloys that can meet the performance requirements under most in-core conditions have been identified. However, for all candidate materials, insufficient data are available to unequivocally ensure acceptable performance and experimental irradiations of candidate core materials will be required. Research programs are to include out-of-pile tests on un-irradiated and irradiated alloys. Ideally, in-flux studies at appropriate temperatures, neutron spectrum, dose rate, duration, and coolant chemistry will be required. Characterization of the microstructure and the mechanical behavior including strength, ductility, swelling, fracture toughness, cracking, and creep on each of the in-core candidate materials will ensure their viability in the Canadian SCWR.

Expression of receptor tyrosine kinase targets PDGFR-β, VEGFR2 and KIT in canine transitional cell carcinoma

Transitional cell carcinoma (TCC) is the most common neoplasia of the canine urinary tract. It tends to be locally invasive and has a moderate metastatic rate. Receptor tyrosine kinases (RTKs) play an important role in promoting cell growth, differentiation and regulation of cell function. RTK inhibitor toceranib phosphate has been used anecdotally to treat TCC. The goal of this study was to evaluate archived normal urinary bladder, TCC and cystitis bladder samples for expression of toceranib phosphate targets: VEGFR2, PDGFR-β and stem cell factor receptor (KIT). A significant number of TCC samples expressed PDGFR-β compared with cystitis and normal bladder samples (P<.0001). While all the tumour samples stained positively for VEGFR2, there was no significant difference between tumour, cystitis and normal bladder samples in intensity scores or staining distribution. Minimal positive staining for KIT was noted in the tumour samples. Based on this proof of target study, further investigation is warranted to determine clinical response of TCC to toceranib phosphate.

Immersing undergraduates into an interprofessional longitudinal rural placement

INTRODUCTION

An Integrated Multidisciplinary Model of Education in Rural Settings (IMMERSe) program was piloted in 2010 in a rural region of South Australia. The aim of the program was to place students from different health programs together, in a rural environment, for one or two semesters of the academic year to promote interprofessional learning. Students were given the opportunity to participate in joint fortnightly education sessions with an emphasis on interprofessional relations and teamwork, undertaking activities such as case studies, role plays, journal club, work shadowing and invited speakers.

METHODS

A qualitative approach was used to explore student perspectives of a rural interprofessional clinical placement. Students were invited to participate in focus groups and reflective writing exercises. This data was analysed in relation to the students' thoughts and reflections around professionalism, teamwork and collegial relationships.

RESULTS

The analysis resulted in three major themes: (1) interprofessional interactions with other students; (2) interprofessional interactions with other health professionals; and (3) interprofessional interactions with the community. Students in our study demonstrated a new level of respect for health professionals outside of their discipline, and gained a sense of how their own independent roles can blend or partner with others' roles, to draw on each other's expertise.

CONCLUSIONS

Student learning experiences can be enhanced through engagement and integration in a rural community context. Interprofessional learning in a rural community placement can increase students' understanding of professionalism, teamwork and collegiality, which are all important components of collaborative practice. Reflective journaling is a useful method for evaluating the student experience.

Pilot evaluation of anterior dynamic ultrasound screening for developmental dysplasia of the hip in an Australian regional hospital

INTRODUCTION

Developmental Dysplasia of the Hip (DDH) is the most common notifiable musculoskeletal birth defect in South Australia (SA). Despite routine screening by physical examination of the hips in the neonatal period and at 6 weeks of age, the risk of late diagnosis is increased in rural areas. It is assumed this is due to the examining doctors' reduced clinical expertise. Introducing Anterior Dynamic Ultrasound (ADUS) has reduced the late detection rates in Sweden to almost zero, and may benefit Australian infants in rural areas if routine screening was introduced. This study reports on a small implementation pilot in a SA regional hospital where volunteer postnatal mothers consented to their babies having ADUS examinations.

METHODS

The pilot was evaluated by collecting results of physical examination, ADUS, and surveying parental impressions of the screening test.

RESULTS

Hips of 86 infants underwent ADUS during the implementation pilot. Parents' perceptions were mainly very positive and indicated ADUS was an accessible and acceptable screening test. Of the hips scanned, three were found to have maximum movement of the femoral head of >3 mm and were deemed to demonstrate increased laxity. Four hips described as loose or mobile on clinical examination were found to be within normal limits of maximum mobility on ADUS.

CONCLUSIONS

This study has demonstrated that a larger scale implementation project would be feasible in regional Australia, and would enable researchers to better understand how to reduce the late diagnosis rate of DDH in rural areas.

Global survey of national tuberculosis drug policies

SETTING

National tuberculosis (TB) programmes (NTPs) in 100 countries.

OBJECTIVES

To evaluate the relationship between the estimated prevalence of multidrug resistance in previously untreated TB cases and policies regarding sales and distribution of TB drugs, particularly rifampicin (RMP).

DESIGN

Questionnaire survey of national TB drug control policies, completed by NTP managers. Results were correlated with recent World Health Organization estimates of prevalence of drug resistance in new cases of TB.

RESULTS

Questionnaires were received from 100 countries, including 88 low- and middle-income countries (LMICs) and 17 of the 22 high-burden countries. Current policies were considered adequate in only 40 of the 88 LMICs (45%). A higher prevalence of multidrug resistance was associated with fewer years of free availability of TB drugs from the NTP (P = 0.02) and more years of availability of RMP from providers or pharmacies outside the NTP (P = 0.02). Eleven of the 20 countries with the highest prevalence of multidrug resistance had inadequate policies governing sales and distribution of TB drugs.

CONCLUSIONS

These findings suggest that policies regarding sales and distribution of TB drugs should receive more emphasis as part of the global strategy to control drug resistance.

Anesthetic implications of a partial molar pregnancy and associated complications

In the United States, molar pregnancy occurs between 1 in 1,200 and 1 in 2,500 pregnancies. The critical nature of complications associated with a molar pregnancy requires advanced perioperative anesthetic management. This case report details the perioperative events of a 34-year-old gravida 5, para 3, with a partial molar pregnancy who underwent general anesthesia for a dilatation and curettage procedure, following therapeutic termination of a coexisting fetus at 18 weeks' gestation. Her initial presentation, anesthetic and operative management, and postoperative course are described clearly. The medical and anesthetic interventions required for treatment of molar pregnancy are reviewed. Of molar pregnancies, 80% are uncomplicated and follow an unremarkable course. However, for the remaining 20%, complications can be severe and may lead to substantial morbidity and mortality in otherwise healthy women.

Hypertension management of medical aid patients attending private practices

OBJECTIVES

The study aimed to describe the treatment status of hypertensive patients and the prescribing patterns of private medical practitioners treating medical aid scheme patients with hypertension.

METHOD

Data on hypertensive patients belonging to medical aid schemes were provided to the drug utilisation review consultancy, Quality Health Services (QHS), by private medical practitioners. The data were computerised and included the age and gender of the patient, the diastolic and systolic blood pressure (BP), the medication prescribed for the condition and the qualifications of the reporting doctor. All the prescribed drugs were categorised into 12 drug classes and combination preparations had each constituent categorised. The level of BP allowed the degree of BP control to be described as controlled (< 140/90 mmHg), borderline (140/90-< 160/95 mmHg) and uncontrolled (> or = 160/95 mmHg).

RESULTS

Included in the study were 11,696 hypertensive patients (46.3% male and 53.7% female) and the 3,503 doctors who cared for them. The systolic BP showed an age-related increase, but the diastolic BP did not. The level of BP control was high, with less than a quarter of patients having uncontrolled hypertension. The most frequently prescribed drug class was angiotensin-converting enzyme (ACE) inhibitors (32.2%). Beta-blockers accounted for 20.8% and calcium antagonists for 14% of all prescriptions. Thiazide and thiazide-like diuretics on their own accounted for only 7.8% of prescriptions. However, a further 13.8% of prescriptions contained this class of diuretics in combination with other drug classes. Diuretics of all classes taken on their own or in combination were used by 33.9% of patients.

CONCLUSIONS

Good levels of hypertension control were reported for hypertensive patients by their private practitioners. Almost half of all prescriptions were for the newer and more costly antihypertensive drugs (ACE inhibitors and calcium antagonists), although their effectiveness in reducing long-term complications of hypertension is still unproven. Furthermore, these prescribing patterns do not conform to those recommended by the Southern African Hypertension Society's hypertension management guidelines.

The safety and efficacy of electroconvulsive therapy in patients over age 75

OBJECTIVES

To examine the safety and efficacy of electroconvulsive therapy (ECT) in patients over the age of 75 years.

METHOD

Retrospective study of all patients over 75 years treated with ECT in three hospitals between 1995 and 1997.

RESULTS

Ninety-three ECT courses were administered during the study period. Ten patients (10.8%) suffered complications following ECT. The most common adverse events were prolonged confusion and hypomania, all of which resolved within 2 weeks of the cessation of treatment. Eighty-five per cent of patients made a marked or moderate response to treatment.

CONCLUSIONS

ECT is a relatively safe and effective procedure in patients over age 75.

New goals for the U.S. Human Genome Project: 1998-2003

The Human Genome Project has successfully completed all the major goals in its current 5-year plan, covering the period 1993-98. A new plan, for 1998-2003, is presented, in which human DNA sequencing will be the major emphasis. An ambitious schedule has been set to complete the full sequence by the end of 2003, 2 years ahead of previous projections. In the course of completing the sequence, a "working draft" of the human sequence will be produced by the end of 2001. The plan also includes goals for sequencing technology development; for studying human genome sequence variation; for developing technology for functional genomics; for completing the sequence of Caenorhabditis elegans and Drosophila melanogaster and starting the mouse genome; for studying the ethical, legal, and social implications of genome research; for bioinformatics and computational studies; and for training of genome scientists.

Alterations in carbohydrate metabolism in dogs with nonhematopoietic malignancies

OBJECTIVE

To determine whether alterations in carbohydrate metabolism exist in dogs with nonhematopoietic malignancies but without evidence of weight loss or cachexia.

ANIMALS

90 dogs with nonhematopoietic malignancies and 18 control dogs.

PROCEDURE

An intravenous glucose tolerance test was done in 90 dogs with previously untreated nonhematopoietic malignancies and in 18 clinically normal dogs. These dogs also had no evidence of unrelated diseases that would affect glucose metabolism. None of the dogs had evidence of cachexia. Samples were assayed for glucose, lactate, and insulin concentrations. This procedure was repeated for 45 of the tumor-bearing dogs from which all gross evidence of tumor was completely excised and evidence of diseases that would alter carbohydrate metabolism did not exist.

RESULTS

The mean of all time points during the intravenous glucose tolerance test (ie, 0, 5, 15, 30, 45, and 60 minutes) for lactate (12.9 +/- 6.7 mg/dl) and insulin (69.1 +/- 44.9 microU/ml) concentrations in untreated dogs with nonhematopoietic malignancies were significantly higher than values for controls (lactate, 9.7 +/- 4.3 mg/dl; and insulin, 31.7 +/- 11.5 microU/ml). This increase in lactate and insulin values did not return to normal when the dogs were rendered free of all observable evidence of cancer after surgery.

CONCLUSIONS

Carbohydrate metabolism is altered in dogs with a variety of nonhematopoietic malignancies and these abnormalities do not abate when dogs are rendered free of gross evidence of malignant disease after surgery.

CLINICAL RELEVANCE

Alterations in carbohydrate metabolism may result in decreased quality of life and may be associated with the paraneoplastic syndrome, cancer cachexia.

Formulary and funding implications of the gap between the national Essential Drugs List and current prescribing in a large health maintenance organisation

BACKGROUND

The Department of Health has prepared an Essential Drugs List (EDL) for public sector implementation in 1996 and future extension to the private sector. Stakeholders have been consulted to ensure that the EDL achieves its objectives of safety, efficacy and quality at the lowest possible cost, while providing coverage for 90-95% of the common and important conditions in the country. This study was undertaken to gain insight into the current use of EDL products by 200 general practitioners (GPs) servicing a large health maintenance organisation (HMO).

METHODS

Approximately 120,000 prescriptions were reviewed and the use of specified EDL medicines, other forms of EDL medicines and non-EDL medicines was analysed for several pharmacological groups. These included antibiotics and medicines for the cardiovascular, musculoskeletal, central nervous, respiratory and gastro-intestinal systems. To gauge potential savings to the private sector through the purchase of EDL products at state tender prices, current prices of a random sample of EDL products were compared.

RESULTS

In the areas reviewed, only 22.4% of current GP prescriptions included EDL items; a further 19.6% included 'other forms of EDL' items. Simply obtaining those EDL products that are currently prescribed at state tender prices would reduce costs by almost 20%, while extending the use of EDL products might save in excess of 70% on private sector GP prescriptions.

CONCLUSIONS

Assuming that all prescriptions were clinically indicated, the 'gap' between the EDL and medicines prescribed indicates that debate will be.

Analysis of paediatric prescribing profiles in two health-funding systems

OBJECTIVE

To investigate the adequacy of two large South African medical administrative databases in providing prescribing profiles for paediatricians and general practitioners (GPs) respectively.

DESIGN

Statistical analysis of data captured during 1994. Data were analysed retrospectively with frequency analysis and non-parametric tests.

SETTING

Two industry databases, one covering a prepaid health maintenance organisation (HMO), the other providing a chronic medication programme for medical schemes and their members.

MAIN OUTCOME MEASURES

Comparison of prescribing profiles of specialists and GPs.

MAIN RESULTS

Data from the HMO revealed that referrals to paediatricians were mainly for gastro-intestinal and respiratory problems. Paediatricians' prescriptions for treatment of gastro-oesophageal reflux and/or abdominal pain represented 15.5% of all items prescribed and accounted for 40.7% of total paediatric medicine costs. GPs used formulary items more frequently, and cost per prescription was two-thirds that of specialists. Data from the chronic medication programme were used to compare treatment of asthma by the two provider groups. There were significant differences in the prescribing profiles of the two groups, with specialists using more in the way of "third-line agents' and newer, expensive products. Significant numbers of prescriptions did not conform to national guidelines for treatment of asthma.

CONCLUSIONS

Industry databases provide a viable and valuable source of information; however, some problems were experienced in extracting the required data. Prescribing profiles revealed certain practices that require review, in particular the relatively low use of generic products, the early resorting to drug therapy for gastrooesophageal reflux, and non-conformity with national guidelines for management of childhood asthma.

Pharmaco-economic assessment of the HMG-CoA reductase inhibitors

OBJECTIVE

To perform a comparative pharmaco-economic assessment of two HMG-CoA reductase inhibitors.

DESIGN

A cost-effectiveness analysis was employed using comparative efficacy data from selected clinical trials. A comprehensive international literature search formed the basis for this selection. Criteria for inclusion of clinical trial results in the analysis were set a priori. Acquisition costs used were the recommended reimbursement prices as at September 1994.

MAIN OUTCOME MEASURES

Two outcome measures are reported: (i) the comparative cost-effectiveness in lowering blood lipid concentrations; and (ii) the comparative cost-effectiveness of the medicines when used to achieve a predetermined therapeutic goal.

RESULTS

The average cost per 1% decrease in total cholesterol is 21.9% higher on 10 mg pravastatin daily than on 10 mg simvastatin daily. Similarly the average cost per 1% decrease in low-density lipoprotein (LDL) cholesterol is 23.1% higher on 10 mg pravastatin than on 10 mg simvastatin daily. This difference is consistent throughout the dosage range. The use of incremental doses of simvastatin monotherapy in order to reach a predetermined therapeutic goal (LDL < or = 4.14 mmol/l) is more cost-effective than an equivalent pravastatin dosage regimen. Total treatment costs for simvastatin-treated patients are 3.5% less than for pravastatin-treated patients. More patients on simvastatin are successfully treated; the difference in overall treatment costs per successfully treated patient is 27.9% in favour of simvastatin. Sensitivity analysis shows these results to be stable under extreme scenarios.

CONCLUSIONS

This analysis employed objective comparative efficacy data obtained from peer-reviewed sources to compare the economic and clinical outcomes of simvastatin and pravastatin in the treatment of hypercholesterolaemia. The acquisition cost of simvastatin is 10.3-22.8% higher than an equivalent milligram dose of pravastatin, depending on the dosage used. However, because of the greater milligram potency of simvastatin, it is a more cost-effective alternative. Simvastatin therefore provides better value for money than pravastatin in lowering lipid levels in clinical practice.

Aspects of roaccutane prescription in South Africa

A nationwide postmarketing surveillance study on the use and outcomes of use of isotretinoin has been conducted in South Africa. A representative sample of prescribers of the drug was identified from drug utilisation data and the overall doctor response rate was 90.1%. A total of 766 patients was enrolled in the study, of which 728 were analysable for safety and efficacy. More than half the patients prescribed isotretinoin were women, of whom only 48.25% were practising some form of contraception. The mean overall dosage prescribed was 0.64 mg/kg/day and the mean overall duration of therapy prescribed was 15.5 weeks. The mean dose and duration of therapy prescribed by dermatologists was significantly higher than that prescribed by general practitioners. Potentially dangerous drug interactions involving the concomitant use of isotretinoin with tetracyclines, vitamin A and oral contraceptives together with antibiotics were noted. Mucocutaneous drying effects were the most common adverse events and the incidence of these effects decreased with continuation of therapy. The known effectiveness of the drug was confirmed by the results of the study.

Germ-line gene modification and disease prevention: some medical and ethical perspectives

There has been considerable debate about the ethics of human germ-line gene modification. As a result of recent advances in the micromanipulation of embryos and the laboratory development of transgenic mice, a lively discussion has begun concerning both the technical feasibility and the ethical acceptability of human germ-line modification for the prevention of serious disease. This article summarizes some of the recent research on germ-line gene modification in animal models. Certain monogenic deficiency diseases that ultimately might be candidates for correction by germ-line intervention are identified. Several of the most frequently considered ethical issues relative to human germ-line gene modification are considered in the context of professional ethics, parental responsibility, and public policy. Finally, it is suggested that there is merit in continuing the discussion about human germ-line intervention, so that this technique can be carefully compared with alternative strategies for preventing genetic disease.

Data monitoring committees: the moral case for maximum feasible independence

Since data monitoring committees (DMCs) began to be established in the 1970s, they have reviewed the clinical outcome data emerging from ongoing trials. The thesis of this essay is that DMCs most effectively promote the validity and credibility of randomized clinical trials when they perform this function with the maximum feasible independence. The essay argues that four types of individuals and groups should be excluded from the interim monitoring of outcome data: (1) investigators entering patients into a trial; (2) principal investigators or study chairs; (3) representatives of commercial firms connected with a trial; and (4) representatives of regulatory agencies. The role of statistical groups and officials of government funding agencies in the review of outcome data is also discussed.

Zocor, the postmarketing experience

The aim of this study was to develop and test a descriptive, intensive drug surveillance methodology in order to examine the effectiveness and safety of new drugs in the immediate postmarketing period. The HMG-CoA reductase inhibitor, simvastatin (Zocor), was chosen as the test drug. Data were collected from 100 randomly chosen cardiologists, specialist physicians and general practitioners practising in the six main centres of South Africa. A 66% doctor response rate was achieved and 438 patients were enrolled in the study. The overall effectiveness expressed as a percentage decrease (from baseline) in total cholesterol levels was 20.5% for the 251 patients who started on a 10 mg daily dose of the drug and 27.6% for the 42 patients who started on 10 mg but changed to 20 mg/d. The safety profile of simvastatin was comparable with the premarketing clinical trial data, and patient non-compliance appeared to be dose-related. The methodology employed was found to be suitable for the collection of safety and effectiveness data in the postmarketing period and simvastatin was shown to be effective with few adverse events reported.

Fibulin is localized at sites of epithelial-mesenchymal transitions in the early avian embryo

Fibulin is a 100-kDa calcium-binding, extracellular matrix (ECM), and plasma glycoprotein (Argraves et al., Cell 58, pp. 623-629, 1989; Argraves et al., J. Cell Biol. 111, 3155-3164). Immunoprecipitation analysis showed that antibodies against human fibulin react with an avian isoform (M(r) 100,000). The spatial and temporal distribution of fibulin was examined in the early avian embryo using immunofluorescence microscopy. In stage 15-22 quail embryos fibulin is a constituent of most basement membranes. Areas undergoing epithelial-mesenchymal transitions such as the endocardial cushions, developing myotomes, and neural crest display especially prominent immunostaining. In the early heart fibulin expression was most pronounced in the cardiac jelly at sites where endocardial cushion cells begin the migrations that lead to the formation of valvular and septal primordia. Laser scanning confocal microscopy showed extensive extracellular accumulations of fibulin on the surface of endocardial mesenchyme cells that were motile at the time of fixation (stage 19). These data suggest that enhanced deposition of fibulin at sites of epithelial-mesenchymal transitions may influence cell behavior.

Human gene therapy: ethics and public policy

The first three human gene transfer/therapy clinical protocols are now underway after having been subjected to an extensive review process by the Recombinant DNA Advisory Committee (RAC) and its Human Gene Therapy Subcommittee. The "Points to Consider" document developed by the RAC established the framework for evaluating genetic intervention protocols. This review process is taking place in a broader social context. Public attitude surveys in this country have indicated a general lack of knowledge in the area of genetic engineering but an acceptance of somatic-cell gene therapy as treatment for disease. Internationally, numerous policy statements on human genetic intervention have been published, all of which support the moral legitimacy of somatic-cell gene therapy for the cure of disease. The debate over the ethical issues related to somatic-cell gene therapy has evolved over a ten-year-period. The time has now come to begin a formal public process for the ethical assessment of germ-line genetic intervention.

Feeling fat: motivations, knowledge, and attitudes of overweight women and men

This study concerned obesity from the perspective of 47 women and 8 men who considered themselves overweight. They responded to a questionnaire about various aspects of motivation to lose weight, knowledge about obesity, and personal and societal attitudes toward the obese. Although they reduced calorie intake and increased exercise when trying to lose weight, they reported various reasons why their exercise levels were less than optimal. Verbal motivation to lose was only partially reflected in willingness to change lifestyle, even though respondents had spent substantial sums of money on weight-loss attempts. Knowledge about obesity was imperfect, with women and thinner subjects somewhat more knowledgeable. Subjects were aware of and shared some of the negative social stereotypes of the obese, blaming themselves for their overweight. However, most would not trade their obesity for other handicaps found less stigmatizing in other research. As expected, women expressed a greater desire for thinness than men. Implications for health care professionals are discussed.

Avian vasculogenesis and the distribution of collagens I, IV, laminin, and fibronectin in the heart primordia

The heart-forming regions of the early embryo are composed of splanchnic mesoderm, endoderm, and the associated ECM. The ECM of the heart-forming regions in stage 7-9 chicken embryos was examined using immunofluorescence. Affinity purified antibodies to chicken collagens type I and IV, chicken fibronectin, and mouse laminin were used as probes. We report that (1) the basement membrane of the endoderm contains immunoreactive laminin and collagen IV; (2) the nascent basement membrane of the heart splanchnic mesoderm contains immunoreactive laminin, but not type IV collagen, and (3) the prominent ECM between the splanchnic mesoderm and the endoderm (the primitive-heart ECM) contains collagen IV, collagen I, fibronectin, but not laminin. In addition, we describe microscopic observations on the spatial relationship of cardiogenic cells to the primitive-heart ECM and the endodermal basement membrane.

Fourier transform infrared spectroscopy for the characterization of a model peptide-DNA interaction

To better understand the structural basis of protein-DNA interactions, the conformational changes that accompany these interactions need to be described. In order to develop a methodological approach to this problem, Fourier transform infrared spectroscopy (FTIR) with derivative resolution enhancement has been used to identify conformational changes that occur when a 29-residue synthetic peptide binds nonspecifically to heterogeneous cellular DNA in aqueous solution. The peptide sequence was chosen de novo, in order to rationally design a peptide model that would allow the relationship between DNA binding and the stability of protein secondary structure to be studied. Peptide at a concentration of 100-200 microM produces 50% saturation of heterogeneous phage DNA sequences as well as of short synthetic oligonucleotides. FTIR spectra reveal significant changes in peptide and DNA upon binding. Second-derivative spectra resolve the amide I band of native peptide into components located at 1627 (beta-strand), 1658 (alpha-helix), and 1681 (turn or beta-strand) cm-1, with a distinct shoulder at 1647 cm-1 (disordered structure). Assignment of the 1681 cm-1 vibration to a turn conformation is supported by uv CD studies, which indicate significant amounts of turn structure in unbound peptide. Ultraviolet CD also confirms the existence of disordered and beta-strand regions in the free peptide. Upon interacting with DNA the band at 1681 cm-1 (turn) is no longer seen; a new band appears at 1675 cm-1; the 1627 cm-1 band (beta-strand) is considerably reduced in intensity; the position of the alpha-helical (1658 cm-1) component remains unchanged; the shoulder at 1647 cm-1 (disorder) disappears. The new vibration at 1675 cm-1 is characteristic of beta-strand structures. The asymmetric stretch (vAS) of the DNA phosphates shifts from 1223 (unbound) to 1229 cm-1 (bound); the relative intensities of vAS and the PO2- symmetric stretch (vS) are altered upon peptide binding.(ABSTRACT TRUNCATED AT 400 WORDS)

Precursors of chondroitin sulfate proteoglycan are segregated within a subcompartment of the chondrocyte endoplasmic reticulum

Immunocytochemical methods were used at the levels of light and electron microscopy to examine the intracellular compartments of chondrocytes involved in extracellular matrix biosynthesis. The results of our studies provide morphological evidence for the compartmentalization of secretory proteins in the ER. Precursors of the large chondroitin sulfate proteoglycan (CSPG), the major proteoglycan species produced by chondrocytes, were present in the Golgi complex. In addition, CSPG precursors were localized in specialized regions of the ER. Link protein, a separate gene product which functions to stabilize extracellular aggregates of CSPG monomers with hyaluronic acid, was segregated similarly. In contrast, type II procollagen, another major secretory molecule produced by chondrocytes, was found homogeneously distributed throughout the ER. The CSPG precursor-containing ER compartment exhibits a variable tubulo-vesicular morphology but is invariably recognized as an electronlucent, smooth membrane-bounded region continuous with typical ribosome-studded elements of the rough ER. The observation that this ER structure does not stain with antibodies against resident ER proteins also suggests that the compartment is a specialized region distinct from the main part of the ER. These results support recent studies that consider the ER as a compartmentalized organelle and are discussed in light of the possible implications for proteoglycan biosynthesis and processing.

Distribution of laminin, collagen type IV, collagen type I, and fibronectin in chicken cardiac jelly/basement membrane

Light microscopic immunolabeling studies were designed to identify and locate structural components within the cell-free extracellular matrix which lies between the embryonic endocardial and myocardial tubes. Affinity-purified antibodies were used to examine stage 15-22 embryonic chicken hearts. Specimens were immunolabeled by using three different methodologies: 1) postembedding labeling of 10 microns cryostat sections, 2) preembedding labeling (en bloc) of whole hearts, and 3) postembedding labeling of ethanol/acetic acid-fixed paraffin sections. Our results establish the spatial distribution of collagen type I and demonstrate for the first time the presence of collagen type IV and laminin in the myocardial-basement-membrane/cardiac jelly.

Peptide and protein synthesis by segment synthesis-condensation

The chemical synthesis of biologically active peptides and polypeptides can be achieved by using a convergent strategy of condensing protected peptide segments to form the desired molecule. An oxime support increases the ease with which intermediate protected peptides can be synthesized and makes this approach useful for the synthesis of peptides in which secondary structural elements have been redesigned. The extension of these methods to large peptides and proteins, for which folding of secondary structures into functional tertiary structures is critical, is discussed. Models of apolipoproteins, the homeo domain from the developmental protein encoded by the Antennapedia gene of Drosophila, a part of the Cro repressor, and the enzyme ribonuclease T1 and a structural analog have been synthesized with this method.

The effects of anticholinergics on the photopalpebral reflex, memory and mood

This study investigated central anticholinergic drug effects on: (1) the Randt Memory Test, a relatively new instrument which measures the acquisition and recall of verbal and pictorial information; (2) the averaged photopalpebral reflex (PPR), an electrophysiological parameter, the validity of which needs to be further investigated in pharmacological research and; (3) mood as measured by a 16-item visual analogue scale. Atropine (1 mg and 2 mg), pirenzepine (20 mg) and a placebo were administered intramuscularly in a double-blind cross-over trial in eight healthy volunteers. There were no inter-treatment differences on the Randt Memory Test. This finding is seemingly in contrast to those reported by some authors using other memory tests. In contrast to the reported effects of some benzodiazepines, the anticholinergics used in the present study did not prolong the latencies of the PPR, but reduced the amplitudes. Visual analogue scales indicated central effects for both pirenzepine and atropine. This implies pirenzepine's penetration of the blood-brain barrier and a physiological function for central muscarinic-1-receptors. The significant anticholinergic effects were exclusive to the "alertness" factor.

Ethical issues in the prevention and treatment of HIV infection and AIDS

The epidemic of infection with the human immunodeficiency virus (HIV) and the acquired immunodeficiency syndrome (AIDS) poses a major ethical question: How can we control the epidemic and the harm that it causes without unjustly discriminating against particular social groups and without unnecessarily infringing on the freedom of individuals? This question pertains to three spheres of public policy in the United States: public health, the delivery of health care, and research. In the public health sphere, vigorous educational efforts will be required, as will modified approaches to intravenous drug use, prostitution, and homosexual and bisexual sexual activity. Carefully targeted, voluntary testing and screening programs should be coupled with counseling and with guarantees of confidentiality and nondiscrimination where these are appropriate. Both health care workers and the health care system have a moral obligation to provide care to people with HIV infection, but heroic self-sacrifice should not be required provided that infection control precautions are observed. Patients with neurological involvement and terminally ill patients will benefit from statutes allowing recognition of advance directives about preferred modes of care or nontreatment. There is a moral imperative to perform intensive research directed toward the understanding, treatment, and prevention of HIV infection and AIDS. The research process will raise challenging ethical questions.

Test-tube babies: ethical considerations

This essay reviews 15 statements on the ethics of in vitro fertilization (IVF) and embryo transfer that were produced between 1979 and 1985. The statements represent the deliberations and conclusions of committees from Australia, Western Europe (including the United Kingdom), Canada, and the United States. From 1979 through the early 1980s, 18 first-generation issues predominated in the ethical discussion. In the mid-1980s eight second-generation issues involving clinical IVF have emerged.