Crystal structures of nucleotide exchange intermediates in the eEF1A-eEF1Balpha complex

In the elongation cycle of protein biosynthesis, the nucleotide exchange factor eEF1Balpha catalyzes the exchange of GDP bound to the G-protein, eEF1A, for GTP. To obtain more information about the recently solved eEF1A-eEF1Balpha structure, we determined the structures of the eEF1A-eEF1Balpha-GDP-Mg2+, eEF1A-eEF1Balpha-GDP and eEF1A-eEF1Balpha-GDPNP complexes at 3.0, 2.4 and 2.05 A resolution, respectively. Minor changes, specifically around the nucleotide binding site, in eEF1A and eEF1Balpha are consistent with in vivo data. The base, sugar and alpha-phosphate bind as in other known nucleotide G-protein complexes, whereas the beta- and gamma-phosphates are disordered. A mutation of Lys 205 in eEF1Balpha that inserts into the Mg2+ binding site of eEF1A is lethal. This together with the structures emphasizes the essential role of Mg2+ in nucleotide exchange in the eEF1A-eEF1Balpha complex.

Risk of hospitalization for cardiovascular disease after use of macrolides and penicillins: a comparative prospective cohort study

Chlamydia pneumoniae has been associated with cardiovascular diseases, and C. pneumoniae infection is treatable with macrolides. In this comparative cohort study, 634 users of macrolides and 3827 users of penicillins were identified from the Danish Health Service Registry of Prescriptions and followed up for an average of 6 months. The patients were then linked to the Regional Hospital Discharge Registry to assess the outcome of hospitalization for cardiovascular disease. In the first 3 months, the relative risk (RR) of admission for a cardiovascular disease was 0.48 (95% confidence interval, 0.27-0.88) in users of macrolides compared with users of penicillins. No difference was seen after 3 months. Interaction analyses indicated that the lower risk seen in users of macrolides could be more pronounced in patients without versus those with a previous cardiovascular disease (RR, 0.39 vs. 0.52), in patients >or=60 versus <60 years old (RR, 0.39 vs. 0.64), and in men versus women (RR, 0.35 vs. 0.67).

Four loops of the catalytic domain of factor viia mediate the effect of the first EGF-like domain substitution on factor viia catalytic activity

The presence of tissue factor is essential for factor VIIa (FVIIa) to reach its full catalytic potential. The previous work in this laboratory demonstrated that substitution of the EGF1 domain of factor VIIa with that of factor IX (FVII((IXegf1))a) results in a substantial decrease in TF-binding affinity and catalytic activity. Supporting simulations of the solution structures of Ca(2+)-bound factor VIIa and FVII((IXegf1))a with tissue factor are provided. Mutants are generated, based on the simulation model, to study the effect of EGF1 substitution on catalytic activity. The simulations show larger Gla-EGF1 and EGF1-EGF2 inter-domain motions for FVII((IXegf1))a than for factor VIIa. The catalytic domain of the chimeric factor VIIa has been disturbed and several surface loops in the catalytic domain of FVII((IXegf1))a (Loop 170s (170-182), Loop 1 (185-188) and Loop 2 (221A-225)) manifest larger position fluctuations than wild-type. The position of Loop 140s (142-152) of FVII((IXegf1))a, near the N terminus insertion site of the catalytic domain, shifts relative to factor VIIa, resulting in a slight alteration of the active site. The results suggest that these four loops mediate the effect of the EGF1 domain substitution on the S1 site and catalytic residues. To test the model, we prepared mutations of these surface loops, including four FVII mutants, D186A, K188A, L144A and R147A, a FVII mutant with multiple mutations (MM3: L144A+R147A+D186A) and a FVII mutant with Loop 170s partially deleted, Loop 170s(del). The catalytic activities towards a small peptidyl substrate decreased 2.4, 4.5 and 9-fold for Loop 170s(del)a (a, activated), L144Aa and D186Aa, respectively, while MM3a lost almost all catalytic activity. The combined results of the simulations and mutants provide insight into the mechanism by which tissue factor enhances factor VIIa catalytic activity.

Does the medical record cover the symptoms experienced by cancer patients receiving palliative care? A comparison of the record and patient self-rating

The aim of this study was to investigate the extent to which the symptoms experienced by advanced cancer patients were covered by the medical records. Fifty-eight patients participated in the study. On the day of first encounter with our palliative care department, a medical history was taken, and on this or the following day, the patients completed the EORTC Quality of Life Questionnaire (EORTC QLQ-C30), Edmonton Symptom Assessment System (ESAS), and Hospital Anxiety and Depression Scale (HADS). The symptomatology reported in the patient-completed questionnaires was compared with the symptomatology mentioned by the physician in the medical record. The analysis revealed good concordance concerning pain, but most other symptoms or problems were reported much more often by patients than by their doctors. Reasons for these discrepancies are discussed. It is suggested that the doctor's knowledge of the patient's symptomatology might gain from more systematic screening and transfer of information from patient self-assessment questionnaires to the medical records.

Risk of adverse birth outcome and miscarriage in pregnant users of non-steroidal anti-inflammatory drugs: population based observational study and case-control study

OBJECTIVE

To estimate the risk of adverse birth outcome in women who take non-steroidal anti-inflammatory drugs during pregnancy.

DESIGN AND SETTING

Population based cohort study and a case-control study, both based on data from a prescription registry, the Danish birth registry, and one county's hospital discharge registry.

PARTICIPANTS

COHORT STUDY: 1462 pregnant women who had taken up prescriptions for non-steroidal anti-inflammatory drugs in the period from 30 days before conception to birth and 17 259 pregnant women who were not prescribed any drugs during pregnancy. CASE-CONTROL STUDY: 4268 women who had miscarriages, of whom 63 had taken non-steroidal anti-inflammatory drugs, and 29 750 primiparous controls who had live births.

MAIN OUTCOME MEASURES

Incidences of congenital abnormality, low birth weight, preterm birth, and miscarriage.

RESULTS

Odds ratios for congenital abnormality, low birth weight, and preterm birth among women who took up prescriptions for non-steroidal anti-inflammatory drugs were 1.27 (95% confidence interval 0.93 to 1.75), 0.79 (0.45 to 1.38), and 1.05 (0.80 to 1.39) respectively. Odds ratios for the taking up of prescriptions in the weeks before miscarriage ranged from 6.99 (2.75 to 17.74) when prescriptions were taken up during the last week before the miscarriage to 2.69 (1.81 to 4.00) when taken up between 7 and 9 weeks before. The risk estimates were no different when the analysis was restricted to missed abortions.

CONCLUSIONS

Use of non-steroidal anti-inflammatory drugs during pregnancy does not seem to increase the risk of adverse birth outcome but is associated with increased risk of miscarriage.

Expression of type III sodium-dependent phosphate transporters/retroviral receptors mRNAs during osteoblast differentiation

Inorganic phosphate (Pi) is essential for the formation of bone. Pi transport in osteoblastic cells is mainly handled by sodium-dependent Pi (NaPi) transporters, different from the renal type I and II transporters; their molecular identities are, however, still subject to investigation. Recently, two type III NaPi transporters, Pit1 and Pit2, were identified, both of which exhibit some of the biochemical and regulatory characteristics of osteoblastic cell-associated NaPi transporters. Here, we have investigated the Pit1 and Pit2 steady-state mRNA levels during the osteoblast differentiation in cultures of the nontransformed MC3T3-E1 cell line. While Pit2 mRNAs were invariably expressed at low levels, Pit1 mRNA levels were found to increase during osteoblast differentiation concomitantly with osteocalcin mRNA. Moreover, the increase in Pit1 mRNA levels also correlated with the time in culture at which mineralization could be observed. The increase in Pit1 mRNA levels over time in culture was only observed in cultures grown under conditions allowing for osteoblast differentiation. This is the first time that osteoblast differentiation-dependent regulation of expression of a NaPi transporter has been demonstrated. Moreover, we show here for the first time the presence of Pit1 and Pit2 mRNAs in undifferentiated and differentiated nontransformed osteoblastic cells. Our data suggest that both Pit1 and Pit2 NaPi transporters are involved in Pi transport in preosteoblastic and osteoblastic cells, and they represent the first evidence consistent with a potential role for Pit1, but not for Pit2, in differentiation-dependent Pi transport. The observed upregulation of Pit1 mRNA levels during osteoblast differentiation suggests that Pit1 might be used as a marker for osteoblast maturation.

Impact of payment method on behaviour of primary care physicians: a systematic review

OBJECTIVE

To review the impact of payment systems on the behaviour of primary care physicians.

METHODS

All randomised trials, controlled before and after studies, and interrupted time series studies that compared capitation, salary, fee-for-service or target payments (mixed or separately) that were identified by computerised searches of the literature. Methodological quality assessment and data extraction were undertaken independently by two reviewers using a data checklist. Study results were qualitatively analysed.

RESULTS

Six studies met the inclusion criteria. There was considerable variation in the quality of reporting, study setting and the range of outcomes measured. Fee-for-service resulted in a higher quantity of primary care services provided compared with capitation but the evidence of the impact on the quantity of secondary care services was mixed. Fee-for-service resulted in more patient visits, greater continuity of care, higher compliance with a recommended number of visits, but lower patient satisfaction with access to a physician compared with salary payment. The evidence of the impact of target payment on immunisation rates was inconclusive.

CONCLUSIONS

There is some evidence to suggest that how a primary care physician is paid does affect his/her behaviour but the generalisability of these studies is unknown. Most policy changes in the area of payment systems are inadequately informed by research. Future changes to doctor payment systems need to be rigorously evaluated.

Crystallization of the yeast elongation factor complex eEF1A-eEF1B alpha

Crystals of the Saccharomyces cerevisiae elongation factor eEF1A (formerly EF-1 alpha) in complex with a catalytic C-terminal fragment of the nucleotide-exchange factor eEF1B alpha (formerly EF-1 beta) were grown by the sitting-drop vapour-diffusion technique, using polyethylene glycol 2000 monomethyl ether as precipitant. Crystals diffract to better than 1.7 A and belong to the space group P2(1)2(1)2(1). The unit-cell parameters of the crystals are sensitive to the choice of cryoprotectant. The structure of the 61 kDa complex was determined with the multiple anomalous dispersion technique using three selenomethionine residues in a 11 kDa eEF1B alpha fragment generated by limited proteolysis of full-length eEF1B alpha expressed in Escherichia coli.

Structural basis for nucleotide exchange and competition with tRNA in the yeast elongation factor complex eEF1A:eEF1Balpha

The crystal structure of a complex between the protein biosynthesis elongation factor eEF1A (formerly EF-1alpha) and the catalytic C terminus of its exchange factor, eEF1Balpha (formerly EF-1beta), was determined to 1.67 A resolution. One end of the nucleotide exchange factor is buried between the switch 1 and 2 regions of eEF1A and destroys the binding site for the Mg(2+) ion associated with the nucleotide. The second end of eEF1Balpha interacts with domain 2 of eEF1A in the region hypothesized to be involved in the binding of the CCA-aminoacyl end of the tRNA. The competition between eEF1Balpha and aminoacylated tRNA may be a central element in channeling the reactants in eukaryotic protein synthesis. The recognition of eEF1A by eEF1Balpha is very different from that observed in the prokaryotic EF-Tu:EF-Ts complex. Recognition of the switch 2 region in nucleotide exchange is, however, common to the elongation factor complexes and those of Ras:Sos and Arf1:Sec7.

Birth outcomes in pregnant women treated with low-molecular-weight heparin

BACKGROUND

Pregnancy and puerperium are associated with an increased risk of venous thromboembolism. Low-molecular-weight heparin is the anticoagulant of choice in pregnant women because, unlike warfarin, it does not cross the placenta. However, there are limited data on the risk of adverse birth outcomes following use of low-molecular-weight heparin in pregnancy.

PATIENTS AND METHODS

We performed a population-based cohort study to examine the safety of low-molecular-weight heparin use in pregnancy using data from the Pharmacoepidemiological Prescription Database, The Danish Medical Birth Registry and the Regional Hospital Discharge Registry in North Jutland County, Denmark. The birth outcomes in a cohort of 66 pregnant women treated with low-molecular-weight heparin between 1991-98 were compared with the birth outcomes of 17,259 pregnant women who did not receive any prescriptive drugs during pregnancy.

RESULTS

No increased risk of malformations, low birth weight or stillbirth was found. However, an increased risk of pre-term delivery was found (odds ratio: 2.11, 95%, confidence interval: 0.96-4.65), which could reflect inherited thrombophilia as an indication of low-molecular-weight heparin.

CONCLUSION

We have provided additional evidence of the safety of low-molecular-weight heparin use in pregnancy.

Oncostatin M and interleukin 6 inhibit cell cycle progression by prevention of p27kip1 degradation in HepG2 cells

We analysed the regulation of G1-phase progression in relation to cytokine receptor signalling in HepG2 hepatoma cells, stably transduced with the IL-10 receptor after stimulation with Oncostatin M (OSM), IL-6, Leukaemia Inhibitory Factor (LIF) and IL-10. All cytokines induced STAT3 phosphorylation to approximately the same level, but only OSM, and to a lesser extent IL-6, induced STAT5 phosphorylation. The cytokines also stimulated phosphorylation of ERK in the order of decreasing effectiveness: OSM > IL-6 > LIF > IL-10. The same order of activity of the cytokines was observed on inhibition of DNA synthesis and accumulation of cells in the G1-phase of the cell cycle. These processes were accompanied by a decrease in cyclin A expression and CDK2 activity, and enhanced accumulation of p27kip1. The level of p27kip1 mRNA expression was unaffected by the cytokines, and maintenance of the elevated level of p27kip1 occurred independently of de novo protein synthesis. Furthermore, inhibition of proteasomal activity increased the level of p27kip1 in the unstimulated cells to the same level as in OSM-treated cells. Inhibition of MEK activation completely abrogated OSM and IL-6 induced p27kip1 accumulation, while expression of dominant negative STAT5 decreased the OSM and IL-6 mediated inhibition of DNA-synthesis and partially inhibited p27kip1 accumulation.

Efficient gene transfer into primary human CD8+ T lymphocytes by MuLV-10A1 retrovirus pseudotype

Efficient and stable gene transfer into primary human T lymphocytes would greatly improve their use for adoptive transfer to treat acquired disorders, viral diseases, and cancer. We have constructed retroviral vector pseudotypes of amphotropic murine leukemia viruses (A-MuLV, MuLV-10A1), gibbon ape leukemia virus (GaLV), and feline endogenous virus (RD114) containing the enhanced green fluorescent protein (GFP) as a marker gene. Transduction of primary human CD8+ T lymphocytes by the different GFP-retrovirus pseudotypes revealed the superiority of MuLV-10A1 in comparison with A-MuLV, GaLV, and RD114, respectively. The superior transduction efficacy of CD8+ T cells by MuLV-10A1 correlates with a longer half-life of this pseudotype in comparison with A-MuLV and, as shown by interference analysis with the human T cell line HUT78, by the utilization of both the A-MuLV receptor (Pit2) and the GaLV receptor (Pit1) for cell entry.

Birth outcomes in women exposed to anticonvulsant drugs

OBJECTIVES

To examine the risk of malformations and fetal growth in women treated with anticonvulsant drugs in North Jutland County, Denmark.

MATERIAL AND METHODS

All women treated with anticonvulsant drugs in the county were identified in a Pharmaco-Epidemiological Prescription Database and linked to the Danish Medical Birth Registry and the Regional Hospital Discharge Registry.

RESULTS

We identified 235 pregnancies exposed to anticonvulsants around conception and/or during pregnancy as well as 17,259 unexposed pregnancies where the mother had not received any prescription. There was 1 case of neural tube defect among 15 malformations in the exposed cohort. The overall risk of malformations was 2.2 (95% confidence intervals 1.3-3.8). The risk of low birth weight and preterm delivery was 1.5 (95% confidence intervals 0.6-3.7) and 1.6 (95% confidence intervals 1.0-2.5), respectively.

CONCLUSION

We found an increased risk of congenital malformations and a tendency to growth retardation in children of women exposed to anticonvulsants.

Squalamine is not a proton ionophore

Squalamine, an aminosterol antibiotic isolated from the dogfish shark, creates relatively large defects in phospholipid bilayers, allowing the unrestricted translocation of small molecules across these compromised membranes (B.S. Selinsky, Z. Zhou, K.G. Fotjik, S. R. Jones, N.R. Dollahon, A.E. Shinnar, Biochim. Biophys. Acta 1370 (1998) 218-234). However, an aminosterol structurally similar to squalamine was found to act as a proton ionophore in anionic phospholipid vesicles. In contrast with squalamine, gross membrane disruption was not observed with this synthetic analog (G. Deng, T. Dewa, S.L. Regen, J. Am. Chem. Soc. 118 (1996) 8975-8976). In this report, the ionophoric activity of squalamine was tested in anionic and zwitterionic phospholipid vesicles. No ionophoric activity was observed for squalamine in vesicles comprised of phosphatidylglycerol (PG), phosphatidylcholine (PC), or a mixture of the two lipids. Experiments using radiolabeled squalamine indicated that all of the squalamine added to PG vesicles remained with the vesicles, while approximately one-half of the squalamine added to PC vesicles was incorporated. We have synthesized the aminosterol analog of squalamine possessing ionophoric activity, and its ionophoric activity in PG vesicles was confirmed. The synthetic compound possessed no measurable lytic activity when added to preformed phospholipid vesicles. As both compounds possess significant antimicrobial activity, these results suggest that either multiple mechanisms for the antimicrobial activity of aminosterols exist, depending upon the aminosterol structure, or possibly an unrelated common mechanism for antimicrobial activity remains to be discovered.

A 13-amino-acid Pit1-specific loop 4 sequence confers feline leukemia virus subgroup B receptor function upon Pit2

Feline leukemia virus subgroup B (FeLV-B) and gibbon ape leukemia virus (GALV) utilize the human protein Pit1 but not the related protein, Pit2, as receptor. A stretch of 9 amino acids, named region A, was identified in the putative fourth extracellular loop of Pit1 (residues 550 through 558) as critical for FeLV-B and GALV receptor function. However, the presence of Pit1 region A did not confer receptor function for FeLV-B upon Pit2, while it did so for GALV. We have here shown that the presence of two Pit1-specific loop 4 residues (tyrosine 546 and valine 548) in addition to Pit1 region A is sufficient to make Pit2 an efficient FeLV-B receptor; that is, a stretch of 13 amino acids encompassing all loop 4 amino acid differences between Pit1 and Pit2 comprises a C-terminal determinant for FeLV-B receptor function. Thus, the same limited receptor region is sufficient to confer receptor function for both viruses upon Pit2.

Target payments in primary care: effects on professional practice and health care outcomes

BACKGROUND

The method by which physicians are paid may affect their professional practice. Although payment systems may be used to achieve policy objectives (e.g. improving quality of care, cost containment and recruitment to under-served areas), little is known about the effects of different payment systems in achieving these objectives. Target payments are a payment system which remunerate professionals only if they provide a minimum level of care.

OBJECTIVES

To evaluate the impact of target payments on the professional practice of primary care physicians (PCPs) and health care outcomes.

SEARCH STRATEGY

We searched the Cochrane Effective Practice and Organisation of Care Group specialised register; the Cochrane Controlled Trials Register; MEDLINE (1966 to October 1997); BIDS EMBASE (1980 to October 1997); BIDS ISI (1981 to October 1997); EconLit (1969 to October 1997); HealthStar (1975 to October 1997) Helmis (1984 to October 1997); health economics discussion paper series of the Universities of York, Aberdeen, Sheffield, Bristol, Brunel, and McMaster; Swedish Institute of Health Economics; RAND corporation; and reference lists of articles.

SELECTION CRITERIA

Randomised trials, controlled before and after studies and interrupted time series analyses of interventions comparing the impact of target payments to primary care professionals with alternative methods of payment, on patient outcomes, health services utilisation, health care costs, equity of care, and PCP satisfaction with working environment.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Two studies were included involving 149 practices. The use of target payments in the remuneration of PCPs was associated with improvements in immunisation rates, but the increase was statistically significant in only one of the two studies.

REVIEWER'S CONCLUSIONS

The evidence from the studies identified in this review is not of sufficient quality or power to obtain a clear answer to the question as to whether target payment remuneration provides a method of improving primary health care. Additional efforts should be directed in evaluating changes in physicians' remuneration systems. Although it would not be difficult to design a randomised controlled trial to evaluate the impact of such payment systems, it would be difficult politically to conduct such trials.

Capitation, salary, fee-for-service and mixed systems of payment: effects on the behaviour of primary care physicians

BACKGROUND

It is widely believed that the method of payment of physicians may affect their clinical behaviour. Although payment systems may be used to achieve policy objectives (e.g. cost containment or improved quality of care), little is known about the effects of different payment systems in achieving these objectives.

OBJECTIVES

To evaluate the impact of different methods of payment (capitation, salary, fee for service and mixed systems of payment) on the clinical behaviour of primary care physicians (PCPs).

SEARCH STRATEGY

We searched the Cochrane Effective Practice and Organisation of Care Group specialised register; the Cochrane Controlled Trials Register; MEDLINE (1966 to October 1997); BIDS EMBASE (1980 to October 1997); BIDS ISI (1981 to October 1997); EconLit (1969 to October 1997); HealthStar (1975 to October 1997) Helmis (1984 to October 1997); health economics discussion paper series of the Universities of York, Aberdeen, Sheffield, Bristol, Brunel, and McMaster; Swedish Institute of Health Economics; RAND corporation; and reference lists of articles.

SELECTION CRITERIA

Randomised trials, controlled before and after studies and interrupted time series analyses of interventions comparing the impact of capitation, salary, fee for service (FFS) and mixed systems of payment on primary care physician satisfaction with working environment; cost and quantity of care; type and pattern of care; equity of care; and patient health status and satisfaction.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Four studies were included involving 640 primary care physicians and more than 6400 patients. There was considerable variation in study setting and the range of outcomes measured. FFS resulted in more primary care visits/contacts, visits to specialists and diagnostic and curative services but fewer hospital referrals and repeat prescriptions compared with capitation. Compliance with a recommended number of visits was higher under FFS compared with capitation payment. FFS resulted in more patient visits, greater continuity of care, higher compliance with a recommended number of visits, but patients were less satisfied with access to their physician compared with salaried payment.

REVIEWER'S CONCLUSIONS

It is noteworthy that so few studies met the inclusion criteria. There is some evidence to suggest that the method of payment of primary care physicians affects their behaviour, but the findings' generalisability is unknown. More evaluations of the effect of payment systems on PCP behaviour are needed, especially in terms of the relative impact of salary versus capitation payments.

Physician contact with older community patients: is there an association with physical fitness?

BACKGROUND

Contact with family physicians by older adults may be linked to their physical fitness in addition to other health, behavioral, and sociodemographic determinants. We studied a stratified random sample of urban community-dwelling elderly patients in London, Ontario, Canada, to describe the interaction of physical fitness measures and a number of health and lifestyle behaviors and sociodemographic outcomes with family physician contact over 1 year. We hypothesized that physician contact would be associated with lower indices of physical fitness and that association would be similar to other known determinants of physician utilization.

METHODS

Three hundred seventy-five noninstitutionalized elderly men (N = 185) and women (N = 190) ages 55 to 84 years were recruited from the municipal tax assessment list for the city of London (population 280,000). Four categories of independent variables were selected to reflect common determinants of health (physical fitness, self-reported and clinically measured health, lifestyle behaviors, and sociodemographics). The association between these categories of variables and self-reported contact with family physicians and a variety of health professionals was determined for the year prior to the study.

RESULTS

Forty-six percent of the subjects had at least one physician contact in the month prior to the study and 79% within the previous year. None of the other health professions (including nursing, chiropractic, physiotherapy, homemaking, and dentistry) were contacted more than once in the previous year. Lifestyle and sociodemographic variables including activity habits, smoking, income, marital status, and education were not associated with physician contact, whereas poor self-reported cardiovascular health and use of cardiovascular and pulmonary medications were associated with physician contact. Interestingly, physical fitness variables including maximal aerobic capacity, grip strength, and hip flexibility were not associated with physician contact.

CONCLUSIONS

The absence of an association among physical fitness, lifestyle, and sociodemographic variables and physician contact was not anticipated and may be due to the selection of individuals who were independent, active community dwellers. It may be that most of the physician contact in this relatively healthy and physically fit sample was preventive in nature, for example, monitoring common chronic disease states in the elderly including cardiovascular and pulmonary disease. This paper reports baseline data from a longitudinal study of the interaction between physical fitness and health outcomes in groups of older community-dwelling individuals. As this group ages further, it would be interesting to determine the use of the health care system in relation to their changing functional and health status. In particular, do chronic health conditions such as cardiovascular disease, which increase in prevalence with age, become modified through maintenance of physical fitness and does this impact on health service use?

Crystal structure of human catecholamine sulfotransferase

Sulfonation, like phosphorylation, can modify the activity of a variety of biological molecules. The sulfotransferase enzymes sulfonate neurotransmitters, drugs, steroid hormones, dietary carcinogens and proteins. SULT1A3 specifically sulfonates catecholamines such as dopamine, adrenaline and noradrenaline. The crystal structure of SULT1A3 with a sulfate bound at the active site, has been determined at 2.4 A resolution. Although the core alpha/beta fold is like that of estrogen and heparan sulfotransferases, major differences occur in and around the active site. Most notably, several regions surrounding the active site, including a section of 40 residues, are disordered in SULT1A3. Regions that are topologically equivalent to the disordered parts of SULT1A3 are involved in substrate and cofactor binding in estrogen and heparan sulfotransferase. Flexibility in these regions suggests that ligand binding elicits a disorder-order transition in and around the active site of sulfotransferases and might contribute to the broad substrate specificity of these enzymes.

Quantification of microvessel density of breast carcinoma: an assessment of the inter- and intraobserver variation

The density profile of microvessels (MVD) has recently emerged as a prognostically independent morphological marker of various malignancies, including carcinoma of the breast. MVD-scoring may thus afford the pathologist the opportunity to identify subsets of early stage breast cancer patients, which may benefit from adjuvant therapy. Reproducibility studies are, however, mandatory. Fifty sections of invasive breast carcinoma, immunolabelled for Factor VIII-related antigen, were scored independently by two observers for the number of vessel-profiles (v-p) in the following manner: 1) 250 randomly selected high power fields (HPF) were scored by two analysts to evaluate the agreement of the counting per se; and 2) the hot spot(s), i.e. the zones considered the most vessel rich, in the 50 sections were identified and scored twice to evaluate the agreement on selecting hot spots. When the observers evaluated MVD in the very same 250 HPF a median deviation of 2 v-p (10%) was produced. The interobserver disparity was further accentuated when the participants independently had to identify the hot spots with a median deviation of 6 v-p (13%). Intraobserver variation was approximately equal to the interobserver discordance. Divergences were most conspicuous in fields with a complex vasculature. In conclusion the v-p scoring resulted in substantial inter- and intraobserver variation both in selecting hot spots and in performing the scoring per se. Alternative-scoring techniques, including strict stereological principles, should be considered in the morphological evaluation of angiogenesis.

Amphotropic murine leukemia virus entry is determined by specific combinations of residues from receptor loops 2 and 4

Pit2 is the human receptor for amphotropic murine leukemia virus (A-MuLV); the related human protein Pit1 does not support A-MuLV entry. Interestingly, chimeric proteins in which either the N-terminal or the C-terminal part of Pit2 was replaced by the Pit1 sequence all retained A-MuLV receptor function. A possible interpretation of these observations is that Pit1 harbors sequences which can specify A-MuLV receptor function when presented in a protein context other than Pit1, e.g., in Pit1-Pit2 hybrids. We reasoned that such Pit1 sequences might be identified if presented in the Neurospora crassa protein Pho-4. This protein is distantly related to Pit1 and Pit2, predicted to have a similar membrane topology with five extracellular loops, and does not support A-MuLV entry. We show here that introduction of the Pit1-specific loop 2 sequence conferred A-MuLV receptor function upon Pho-4. Therefore, we conclude that (i) a functional A-MuLV receptor can be constructed by combining sequences from two proteins each lacking A-MuLV receptor function and that (ii) a Pit1 sequence can specify A-MuLV receptor function when presented in another protein context than that provided by Pit1 itself. Previous results indicated a role of loop 4 residues in A-MuLV entry, and the presence of a Pit2-specific loop 4 sequence was found here to confer A-MuLV receptor function upon Pho-4. Moreover, the introduction of a Pit1-specific loop 4 sequence, but not of a Pit2-specific loop 4 sequence, abolished the A-MuLV receptor function of a Pho-4 chimera harboring the Pit1-specific loop 2 sequence. Together, these data suggest that residues in both loop 2 and loop 4 play a role in A-MuLV receptor function. A-MuLV is, however, not dependent on the specific Pit2 loop 2 and Pit2 loop 4 sequences for entry; rather, the role played by loops 2 and 4 in A-MuLV entry can be fulfilled by several different combinations of loop 2 and loop 4 sequences. We predict that the residues in loops 2 and 4, identified in this study as specifying A-MuLV receptor function, are to be found among those not conserved among Pho-4, Pit1, and Pit2.

Risk of acute pancreatitis in patients with chronic inflammatory bowel disease. A Danish 16-year nationwide follow-up study

BACKGROUND

There are few epidemiologic data about the risk of acute pancreatitis in chronic inflammatory bowel diseases; we therefore wanted to estimate the risk of a first episode of acute pancreatitis in patients with Crohn's disease and ulcerative colitis in the total Danish population.

METHODS

The study included all patients discharged from Danish hospitals with a diagnosis of Crohn's disease or ulcerative colitis registered in the Danish National Registry of Patients in the period from 1977 to 1992. The first episode of acute pancreatitis was identified in the cohort. The observed number of patients with acute pancreatitis was compared with expected numbers on the basis of age, sex, and calendar-specific incidence rates in the general population.

RESULTS

Overall, 15,526 patients were discharged and followed up for 112,824 person-years. The standardized incidence ratio (SIR) for acute pancreatitis was increased both in patients with Crohn's disease (SIR = 4.3; 95% confidence interval (CI), 2.9-6.1) and in those with ulcerative colitis (SIR= 2.1; 95% CI, 1.6-2.8).

CONCLUSION

Patients with chronic inflammatory bowel disease seem to be at increased risk of acute pancreatitis. Further validation and refinement of this registration-based study are needed.

How should we pay doctors? A systematic review of salary payments and their effect on doctor behaviour

We reviewed the published and unpublished international literature to determine the influence of salaried payment on doctor behaviour. We systematically searched Medline, BIDS Embase, Econlit and BIDS ISI and the reference lists of located papers to identify relevant empirical studies comparing salaried doctors with those paid by alternative methods. Only studies which reported objective outcomes and measures of the behaviour of doctors paid by salary compared to an alternative method were included in the review. Twenty-three papers were identified as meeting the selection criteria. Only one of the studies in this review reported a proxy for health status, but none examined whether salaried doctors differentiated between patients on the basis of health needs. Therefore, we were unable to draw conclusions on the likely impact of salaried payment on efficiency and equity. However, the limited evidence in our review does suggest that payment by salaries is associated with the lowest use of tests, and referrals compared with FFS and capitation. Salary payment is also associated with lower numbers of procedures per patient, lower throughput of patients per doctor, longer consultations, more preventive care and different patterns of consultation compared with FFS payment.

RNA levels of human retrovirus receptors Pit1 and Pit2 do not correlate with infectibility by three retroviral vector pseudotypes

The gibbon ape leukemia virus (GaLV) and the amphotropic murine leukemia virus (A-MuLV) infect human cells via specific receptors, Pit1 and Pit2, respectively. mRNA levels of these receptors were determined by Northern analysis and for Pit2 in addition by quantitative RT-PCR. Pit1 and Pit2 were expressed in different amounts in human tissues and cell lines; Pit1-specific mRNA was generally more abundant than Pit2 mRNA. No correlation was found between Pit1 and Pit2 RNA levels and infectibility by GaLV and A-MuLV pseudotyped vectors, respectively. GaLV and A-MuLV revealed a partial reciprocal interference. MuLV-10A1 can utilize both Pit1 and Pit2 for entry into cells but could not infect any of the 14 human cell lines more efficiently than A-MuLV or GaLV. Interference assays suggested that MuLV-10A1 has a higher affinity for and infected most cells predominantly by Pit2. However, at least in one cell line it used Pit1 more efficiently for entry. We conclude that (1) Pit1 and Pit2 mRNA levels in human cells are not indicative of the infectibility by GaLV and A-MuLV pseudotypes, respectively; (2) A-MuLV can infect target cells as efficiently as can GaLV, although Pit2 RNA is less abundant than Pit1 RNA; (3) factor(s) in addition to the presence of Pit1 and Pit2 are involved in retroviral infection; and (4) MuLV-10A1 pseudotype does not infect human cells more efficiently than do A-MuLV and GaLV pseudotypes.

[Denmark's first research facility in palliative medicine. Organization and research strategy]

Denmark's first palliative medicine research unit is now being set up at Bispebjerg Hospital, with single-room and two double-room ward. The multidisciplinary team consists of doctors, a psychologist, nurses, a physiotherapist, an ergotherapist, a medical social worker, a priest and a dietician. An out-patient facility is also being established to enable patients to choose between hospitalisation out-patient treatment or home treatment by appropriate staff. Another aspect of palliative medicine is care of the patient's family members. The intervention offered at our facility is led by a psychologist, and consists primarily of counselling. With its limited clinical opacity, the department of palliative medicine is first and foremost a research and development facility. The first chair in palliative medicine in Denmark was conferred upon the department in 1998.

Single amino acid insertion in loop 4 confers amphotropic murine leukemia virus receptor function upon murine Pit1

Pit1 is the human receptor for gibbon ape leukemia virus (GALV) and feline leukemia virus subgroup B (FeLV-B), while the related human protein Pit2 is a receptor for amphotropic murine leukemia virus (A-MuLV). The A-MuLV-related isolate 10A1 can utilize both Pit1 and Pit2 as receptors. A stretch of amino acids named region A was identified in Pit1 (residues 550 to 558 in loop 4) as critical for GALV and FeLV-B receptor function. We have here investigated the role of region A in A-MuLV and 10A1 entry. Insertion of a single amino acid in region A of mouse Pit1 resulted in a functional A-MuLV receptor, showing that region A plays a role in A-MuLV infection. Moreover, the downregulation of 10A1 receptor function by changes in region A of human Pit1 indicates that this region is also involved in 10A1 entry. Therefore, region A seems to play a role in infection by all viruses utilizing Pit1 and/or Pit2 as receptors.

Primary care. Burden of proof

Evidence that the shift of services from secondary to primary care is creating extra work for GPs is limited. A study showed that it is possible to quantify additional workload for GPs, but that certain aspects, such as measuring the time input, remain problematic. Future research needs to agree workload definitions, employ sensitive measures other than consultation rates, and distinguish between workload in practices and that of individual practitioners.

Fungal phosphate transporter serves as a receptor backbone for gibbon ape leukemia virus

Pit1, the receptor for gibbon ape leukemia virus (GALV), is proposed to be an integral membrane protein with five extracellular loops. Chimeras made between Pit1 homologs differing in permissivity for infection and between Pit1 and the related protein Pit2 have shown that the fourth extracellular loop plays a critical role in infection. However, further elucidation of the roles of the extracellular loops in infection is hampered by the high level of sequence similarity among these proteins. The sodium-dependent phosphate transporter, Pho-4, from the filamentous fungus Neurospora crassa is distantly related to Pit1 and -2, showing an amino acid identity of only 35% to Pit1 in the putative extracellular loops. We show here that Pho-4 itself does not function as a receptor for GALV. Introduction of 12 Pit1-specific amino acid residues in the putative fourth extracellular loop of Pho-4 resulted in a functional GALV receptor. Therefore, the presence of a Pit1 loop 4-specific sequence is sufficient to confer receptor function for the mammalian retrovirus GALV on the fungal phosphate transporter Pho-4.

Sequence and genetic analysis of the hemin storage (hms) system of Yersinia pestis

We have sequenced a region from the pigmentation (pgm) locus of Yersinia pestis KIM6+ that is identified with the exogenous hemin storage (Hms+) phenotype in cells grown at 26 but not at 37 degrees C. The hmsHFRS locus encodes a putative polycistronic operon, with hmsH encoding an outer membrane protein with a deduced molecular mass of 93.4/89.5 (unprocessed/processed) kDa. The mature HmsH 788 aa polypeptide has a pI of 4.99. The hmsF gene has an open reading frame of 654 aa, encoding a 74.6/72.2 kDa OM protein with a pI of 5.16 when processed. A deduced 423 aa, 52 kDa protein with a pI of 10.83 is encoded by hmsR. HmsR has a basic, hydrophilic, and alpha-helical carboxyl terminus; 13 aa at the amino-terminal end and a 'KRKRAR' sequence at the carboxy-terminal end are essential for an Hms+ phenotype. The hmsS gene encodes a hypothetical 155 aa, 17.5 kDa protein with a pI of 6.68. Hms- Y. pestis strain M23-2 transformed with the cloned hmsHFRS locus developed an Hms(c) phenotype (Hms+ at 26-37 degrees C) due to mutations in genes outside the pgm locus.

Mapping of a major osteomagenic determinant of murine leukemia virus RFB-14 to non-long terminal repeat sequences

Certain isolates of murine leukemia viruses (MuLVs) have, apart from a leukemogenic potential, the capability of inducing diseases of nonhematopoietic tissues in susceptible strains of mice. We have reported on the molecular cloning of a bone-tumorigenic virus, RFB-14 MuLV, which was found to induce benign bone tumors, osteomas, with 100% incidence in mice of the CBA/Ca strain (L. Pedersen, W. Behnisch, J. Schmidt, A. Luz, F. S. Pedersen, V. Erfle, and P. G. Strauss, J. Virol. 66:6186-6190, 1992). In order to analyze the bone tumor-inducing phenotype of RFB-14 MuLV, we have studied the pathogenic potential of recombinant viruses between RFB-14 and the nonosteomagenic, highly leukemogenic SL3-3 MuLV. The recombinants were constructed so as to reveal whether a major determinant of osteomagenicity maps to sequences within or outside the long terminal repeats (LTR). Our data show that a major determinant of the osteoma-inducing potential of RFB-14 MuLV maps to the non-LTR region of the genome. Furthermore, we demonstrate that a strong determinant of leukemogenicity is harbored by the non-LTR region of SL3-3 MuLV.

Nurse-conducted smoking cessation with minimal intervention in a lung clinic: a randomized controlled study

This study aimed to evaluate the effect of a motivational, minimal intervention approach to smoking cessation in an open, randomized design conducted by nurses as routine work in a lung clinic. Subjects who smoked less than 10 cigarettes x day(-1), and subjects who smoked > or = 10 cigarettes x day(-1) and who had refused to participate in a smoking cessation trial with nicotine replacement therapy, were randomly allocated to a motivational approach to smoking cessation or to a control group. The motivational approach consisted of a nurse-conducted 5 min consultation concerning reasons to quit smoking, brochures about smoking cessation and advice about how to quit. After 4-6 weeks, subjects in the motivational group received a letter encouraging them to quit smoking. After 1 year, all subjects were contacted by phone and smoking status reported. Subjects claiming to be abstinent attended the clinic for carbon monoxide verification. A total of 507 subjects were enrolled, 254 in the motivational group and 253 in the control group. The mean age of the motivational group was 51 yrs, 50% were males and they smoked a mean of 13 cigarettes x day(-1). The mean age of the control group was 53 yrs, 61% were males and they smoked a mean of 12 cigarettes x day(-1). At the 1 year follow-up, the success rate for point prevalence (no smoking at 1 year and during the preceding month) was 8, 7% in the motivational group versus 3.6% in the control group (p=0.025). The 12 months sustained success rate (no smoking at all during the year) was 3.1 versus 1.2% (p=0.22). The point prevalence for light smokers (<10 cigarettes x day(-1)) was 13.9% in the motivational group versus 6.3% in control group (p=0.12), and for heavy smokers (10 or more cigarettes x day(-1)) 5.2% versus 1.9% (p=0.20). In conclusion, the effect of this nurse-conducted, minimal intervention, motivational approach seems promising as the quit rate at 1 year follow-up had doubled.

Molecular modeling of the amino-terminal zinc ring domain of BRCA1

The equine herpes virus zinc ring domain nuclear magnetic resonance structure was used for homology-based modeling of the amino-terminal zinc ring domain of the BRCA1 breast and ovarian cancer susceptibility gene. The zinc ring domain of BRCA1 is of particular interest because it is the location of significant and frequently occurring missense (Cys(61)Gly, Cys(64)Gly, and Cys(64)Tyr) and frameshift (185delAG) mutations observed in several high-risk kindreds. The BRCA1 zinc ring domain possesses 54% sequence similarity with the equine herpes virus zinc ring domain. The model structure undergoes little conformational variance after 140 ps of solvated molecular dynamics. This model proposes BRCA1 zinc ring domain residues that may play a role in DNA binding and/or protein-protein interactions. These predictions provide a point of departure for the design of mutants to probe BRCA1 zinc ring domain functionality.

Medullary carcinoma of the breast. Prevalence and prognostic importance of classical risk factors in breast cancer

In an earlier study of 235 breast cancers with medullary features, we concluded from a multivariate Cox regression analysis that only four histopathological features contained significantly positive prognostic information. In the present study, continuing our work on the same population base, we used these histological characteristics (predominantly syncytial growth pattern, no tubular component, diffuse stromal infiltration with mononuclear cells and sparse necrosis (< 25%), as diagnostic criteria for medullary carcinoma of the breast (MC). We found a significantly better prognosis for patients with MC than those with non-medullary carcinoma (NMC) or infiltrating ductal carcinoma (IDC). All tumours in the MC group were grade II or III (96% grade III). A significantly different distribution of general risk factors such as lymph node status, invasion, steroid receptor status, and menopausal status, was found between the group of MC and the control group of IDC grades II + III. Further, general risk factors, which are found to be of major prognostic importance in IDC, had little prognostic impact in MC. We found MC to be biologically unique, and patients with MC have a better than average prognosis compared to that of IDC. We propose a new histological definition of MC, but stress that prospective studies have to be performed.

Homology modeling and molecular dynamics simulation of human prothrombin fragment 1

The crystallographic structure of bovine prothrombin fragment 1 bound with calcium ions was used to construct the corresponding human prothrombin structure (hf1/Ca). The model structure was refined by molecular dynamics to estimate the average solution structure. Accommodation of long-range ionic forces was essential to reach a stable solution structure. The gamma-carboxyglutamic acid (Gla) domain and the kringle domain of hf1/Ca independently equilibrated. Likewise, the hydrogen bond network and the calcium ion coordinations were well preserved. A discussion of the phospholipid binding of the vitamin K-dependent coagulation proteins in the context of the structure and mutational data of the Gla domain is presented.

Chimeras of receptors for gibbon ape leukemia virus/feline leukemia virus B and amphotropic murine leukemia virus reveal different modes of receptor recognition by retrovirus

Glvr1 encodes the human receptor for gibbon ape leukemia virus (GALV) and feline leukemia virus subgroup B (FeLV-B), while the related gene Glvr2 encodes the human receptor for amphotropic murine leukemia viruses (A-MLVs). The two proteins are 62% identical in their amino acid sequences and are predicted to have 10 transmembrane domains and five extracellular loops. A stretch of nine amino acids (region A) in the predicted fourth extracellular loop was previously shown to be critical for the function of Glvr1 as receptor for GALV and FeLV-B. Glvr1 and -2 show clusters of amino acid differences in several of their predicted extracellular loops, with the highest degree of divergence in region A. Chimeras were made between the two genes to further investigate the role of Glvr1 region A in defining receptor specificity for GALV and FeLV-B and to map which regions of Glvr2 control receptor specificity for A-MLVs. Region A from Glvr1 was sufficient to confer receptor specificity for GALV upon Glvr2, with the same chimera failing to act as a receptor for FeLV-B. However, introduction of additional N- or C-terminal Glvr1-encoding sequences in addition to Glvr1 region A-encoding sequences resulted in functional FeLV-B receptors. Therefore, FeLV-B is dependent on Glvr1 sequences outside region A for infectivity. The receptor specificity of Glvr2 for A-MLV could not be mapped to a single critical region; rather, N-terminal as well as C-terminal Glvr2-encoding sequences could confer specificity for A-MLV infection upon Glvr1. Surprisingly, though GALV/FeLV-B and A-MLV belong to different interference groups, some chimeras functioned as receptors for all three viruses.

Akv murine leukemia virus enhances bone tumorigenesis in hMT-c-fos-LTR transgenic mice

hMt-c-fos-LTR transgenic mice (U. Rüther, D. Komitowski, F. R. Schubert, and E. F. Wagner. Oncogene 4, 861-865, 1989) developed bone sarcomas in 20% (3/15) of females at 448 +/- 25 days and in 8% (1/12) of males at 523 days. After infection of newborns with Akv, an infectious retrovirus derived from the ecotropic provirus of the AKR mouse, 69% (20/28) of female animals and 83% (24/29) of males developed malignant fibrous-osseous tumors. The tumors in infected transgenics developed with higher frequency and a 200-days shorter mean tumor latency period. The hMt-c-fos-LTR transgene was expressed in all the fibrous-osseous tumors. They also showed newly integrated Akv proviruses, but in most tumors Akv was detected and expressed in only a small number of the tumor cells. Wild-type C3H mice infected with Akv developed benign osteomas with an incidence of 33% and a latency period of 474 days. The data indicate that Akv exerts distinct pathogenic effects on the skeleton. In hMt-c-fos-LTR transgenic mice, predisposed to bone sarcomagenesis, Akv acts synergistically with the fos transgene, resulting in the development of fibrous-osseous tumors.