An integrated program for evidence-based medicine in medical school

To provide optimal care for their patients, clinicians must be able to locate and interpret the most current literature. Teaching the necessary skills to medical students is essential, if we wish to train clinicians to be able to keep up with the expansion of biomedical knowledge for their entire working lives. In this paper, we describe our school's four-year curriculum in evidence-based medicine and the performance of three senior classes on the summative evaluation exercise devised to measure the program's success.

Ubiquitylation and destruction of endogenous c-mycS by the proteasome: are myc boxes dispensable?

c-MycS proteins are truncated forms of the transcription factor which have been shown to be produced by translation initiation at internal methionines (101, 121, and 134) and to be functional in the regulation of gene expression, cell proliferation, and apoptosis. Treatment of human leukemia HL60 cells with lactacystin, a specific inhibitor of the proteasome, increased the steady-state levels of endogenous c-MycS proteins. The half-life of endogenous [(35)S]MycS was similar to that of c-Myc ( approximately 23 min) in HL60 cells. c-Myc(Delta2-143), which lacks the transcription regulatory domain, had a half-life which was similar to that of endogenous c-Myc in 293 and HL60 cells. Treatment of the cells with lactacystin stabilized [(35)S]Myc(Delta2-143) and [(35)S]Myc and caused multi-ubiquitin conjugates of c-Myc, c-MycS, and Myc(Delta2-143) to accumulate. These findings indicate that the Myc homology boxes and the rest of the transcription regulatory domain (the first 144 amino acids) are dispensable for ubiquitylation and rapid destruction of c-MycS and c-Myc by the proteasome.

B(1) and B(2) bradykinin receptors on adventitial fibroblasts of cerebral arteries are coupled to recombinant eNOS

Our previous ex vivo and in vivo studies reported that expression of the recombinant endothelial nitric oxide (NO) synthase (eNOS) gene in adventitial fibroblasts recovers NO production in arteries without endothelium in response to bradykinin. The present study was designed to characterize subtypes of bradykinin receptors on adventitial fibroblasts coupled to the activation of recombinant eNOS. Endothelium-denuded segments of canine basilar arteries were transduced with beta-galactosidase (beta-Gal) gene or eNOS gene ex vivo, using a replication-defective adenoviral vector (10(10) plaque-forming units/ml) for 30 min at 37 degrees C. Twenty-four hours later, isometric force recording or cGMP measurement was carried out. B(1) bradykinin receptor agonist (des-Arg(9)-bradykinin, 10(-10)-10(-8) mol/l) did not significantly affect vascular tone in control or beta-Gal gene-transduced canine basilar arteries without endothelium. In contrast, this agonist caused concentration-dependent relaxations in recombinant eNOS gene-transduced arteries without endothelium. Relaxations to B(1) receptor agonist in the eNOS arteries were abolished by B(1) receptor antagonist (des-Arg(9)-[Leu(8)]bradykinin, 6 x 10(-9) mol/l) but not by B(2) receptor antagonist (Hoe-140, 5 x 10(-8) mol/l). Bradykinin did not significantly alter vascular tone in control or beta-gal arteries without endothelium, whereas this peptide (10(-11)-10(-8) mol/l) induced concentration-dependent relaxations, as well as an increase in cGMP formation in endothelium-denuded eNOS-transduced arteries. Stimulatory effects of bradykinin were prevented in the presence of a B(2) receptor antagonist but not in the presence of a B(1) receptor antagonist. B(1) and B(2) receptor antagonists had no effect on relaxations to substance P, confirming the selectivity of the compounds. Our results suggest that B(1) and B(2) bradykinin receptors are coupled to activation of recombinant eNOS expressed in adventitial fibroblasts.

Effects of recombinant eNOS gene expression on reactivity of small cerebral arteries

Resistance arteries are an important target for vascular gene therapy because they play a key role in the regulation of tissue blood flow. The present study was designed to determine the effects of recombinant endothelial (e) nitric oxide synthase (NOS) gene expression on vasomotor reactivity of small brain stem arteries (internal diameter, 253 +/- 2.5 microm). Arterial rings were exposed ex vivo to an adenoviral vector (10(9) and 10(10) plaque-forming units/ml) encoding eNOS gene or beta-galactosidase gene. Twenty-four hours after transduction, vascular function was examined by isometric force studies. Transgene expression was evident mainly in adventitia. In arteries with endothelium transduced with eNOS gene but not with control beta-galactosidase gene, relaxations to bradykinin and substance P were significantly augmented. Removal of endothelium abolished relaxations to bradykinin and substance P in control and beta-galactosidase arteries. However, in endothelium-denuded arteries transduced with recombinant eNOS, bradykinin and substance P caused relaxations that were abolished in the presence of the NOS inhibitor N(G)-nitro-L-arginine methyl ester. In control arteries, endothelium removal augmented relaxations to the nitric oxide donors sodium nitroprusside and diethylamine NONOate. This augmentation was absent in eNOS gene-transduced arteries without endothelium. Our results suggest that, in small brain stem arteries, expression of recombinant eNOS increases biosynthesis of nitric oxide. Adventitia of small arteries is a good target for expression of recombinant eNOS. Genetically engineered adventitial cells may serve as a substitute source of nitric oxide in cerebral arteries with dysfunctional endothelium.

It's time: record linkage--the vision and the reality

OBJECTIVE

To examine reasons for the minimal use of Australian administrative health data for research and evaluation.

METHOD

Legislative, organisational, social and political barriers in Australia are described.

RESULTS

System changes are identified that would support the implementation of an evaluation-oriented health data collection system. A Universal Patient Identifier is essential. Leadership and funding at the federal level will be required to ensure the co-ordinated introduction of a rational and integrated health data system in Australia.

CONCLUSIONS

Health data in Australia is not currently collected in a manner that allows the assessment of health outcomes. It is time to change the basis of health data collection from accounting to health outcomes evaluation and to reorganise the system to support this.

IMPLICATIONS

If appropriate national health data were available, research and evaluation of services could be undertaken and treatment outcomes and adverse events could be monitored. Such information could provide a basis for targeted clinical trials and provide evidence for best clinical practice.

Universal PCR amplification of mouse immunoglobulin gene variable regions: the design of degenerate primers and an assessment of the effect of DNA polymerase 3' to 5' exonuclease activity

Degenerate primers were designed for PCR amplification of unknown mouse immunoglobulin (Ig) light (L) and heavy (H) chain variable (V) genes. Each subgroup of mouse Ig gene sequences [Kabat, E.A., Wu, T. T., Perry, H.H., Gottesman, K.S., Foeller, C., 1991. Sequences of Proteins of Immunological Interest, 5th edn. US Department of Health and Human Services, Public Health Service, NIH.] was analyzed, and highly degenerate primers in the framework one (FR1) region were designed. A single highly degenerate FR1 primer sufficed for the amplification of light chains; for heavy chains, a series of FR1 primers was used. At the same time, we assessed the effect of 3' to 5' exonuclease activity of DNA polymerase on the utilization of these degenerate primers. Using Taq polymerase, which lacks 3' to 5' exonuclease activity, we successfully amplified the Ig VL and VH genes expressed in more than a hundred monoclonal hybridoma cell lines reactive against a phosphonamidate hapten. Sequence analysis of the cloned VL and VH genes, 52 of each, showed that they are derived from multiple germline families (10 of the 17 VL families and 9 of the 14 VH families) as recently defined [Martinez, C., Lefranc, M., 1998. The mouse (Mus musculus) immunoglobulin kappa variable (IGKV) genes and joining (IGKJ) segments. Exp. Clin. Immunogenet. 15, 184.]. The universality of our primers was also demonstrated by successful amplification of other mouse hybridoma cell lines that are specific to different antigens.

A phase I and pharmacokinetic study of the mitochondrial-specific rhodacyanine dye analog MKT 077

This Phase I study was performed to evaluate the tolerability and pharmacokinetic behavior of MKT-077, a water soluble rhodacyanine dye analogue, which partitions into tumor cell mitochondria where it is thought to act as a metabolic poison, leading to G1 arrest and apoptosis. Thirteen patients with advanced solid malignancies were treated with MKT-077 administered as a 30-min i.v. infusion weekly for 4 weeks every 6 weeks at doses ranging from 42 to 126 mg/m2/week. The principal toxicity was renal magnesium wasting, which was dose-limiting (grade 3) in one patient at each of the 84- and 126-mg/m2 dose levels. The other three patients at the 126-mg/m2 dose level developed grade 2 hypomagnesemia, which was cumulative in nature, improved with i.v. magnesium supplementation, and was controlled in two patients by the administration of prophylactic magnesium before and after treatment with MKT-077. Given the requirement for extensive monitoring of serum magnesium levels, dose escalation >126 mg/m2 was not considered feasible. Thus, the recommended dose for disease-oriented studies with this schedule of MKT-077 is 126 mg/m2/week. Pharmacokinetic studies revealed a prolonged terminal half-life (37 +/- 17 h) and a large volume of distribution (685 +/- 430 liters/m2). Clearance averaged 39 +/- 13 liters/h/m2. Peak MKT-077 plasma concentrations (1.2 +/-0.31 to 6.3 +/- 5.3 microg/ml) exceeded the IC50 concentrations required for human CX-1 colon, MCF-breast, CRL-1420 pancreas, EJ bladder, and LOX melanoma tumor cell lines in vitro (0.15-0.5 microg/ml). These results indicate that at the recommended dose level of 126 mg/m2/week of MKT-077, the toxicity profile was consistent with the preferential accumulation of the agent within tumor cell mitochondria, and biologically relevant plasma concentrations were achieved.

Phase I and pharmacologic study of the specific matrix metalloproteinase inhibitor BAY 12-9566 on a protracted oral daily dosing schedule in patients with solid malignancies

PURPOSE

To evaluate the feasibility of administering BAY 12-9566, a matrix metalloproteinase (MMP) inhibitor with relative specificity against MMP-2, MMP-3, and MMP-9, on a protracted oral daily dosing schedule in patients with advanced solid malignancies. The study also sought to determine the principal toxicities of BAY 12-9566, whether plasma BAY 12-9566 steady state concentrations (C(ss)) of biologic relevance could be sustained for prolonged periods, and whether BAY 12-9566 affected plasma concentrations of MMP-2, MMP-9, and tissue inhibitor of MMP-2 (TIMP-2).

PATIENTS AND METHODS

Patients with solid malignancies were treated with BAY 12-9566 at daily oral doses ranging from 100 to 1,600 mg. BAY 12-9566 dose schedules included 100 mg once daily, 400 mg once daily, 400 mg twice daily, 400 mg three times daily, 400 mg four times daily, and 800 mg twice daily. Plasma was collected to study the range of BAY 12-9566 C(ss) values achieved, and exploratory studies were performed to assess the effects of BAY 12-9566 on plasma concentrations of MMP-2, MMP-9, and TIMP-2.

RESULTS

Twenty-one patients were treated with 47 28-day courses of BAY 12-9566. The most common side effects were headache, nausea, vomiting, abnormalities in hepatic functions, and thrombocytopenia, which were rarely clinically significant. BAY 12-9566 was well tolerated on all dose schedules, and there was no consistent dose-limiting toxicity that precluded treatment in the range of dose schedules evaluated. Instead, dose escalation was terminated because BAY 12-9566 plasma C(ss) values increased less than proportionately and plateaued as the daily dose was increased within the dose range of 100 to 1,600 mg/d, suggesting saturable drug absorption. Mean plasma C(ss) values achieved with all dose schedules exceeded BAY 12-9566 concentrations required to inhibit MMPs in vitro and in vascular invasion and tumor proliferation in vivo models. There were no consistent effects of BAY 12-9566 on the plasma concentrations of MMP-2 and MMP-9 over the continuous dosing period at any dose schedule level. However, plasma levels of TIMP-2 seemed to increase in a dose-dependent manner (r(2) =.50, P =.046).

CONCLUSIONS

The recommended dose of BAY 12-9566 for subsequent disease directed studies is 800 mg twice daily, which resulted in biologically relevant plasma C(ss) values and an acceptable toxicity profile. Although exploratory studies of MMPs in plasma were not revealing, it is conceivable that some tumor types and disease settings are more likely to produce more readily quantifiable levels of activated MMPs than others. Therefore, attempts to identify and quantify surrogate markers of MMP inhibitory effects should continue to be performed in disease-directed studies in more homogenous patient populations.

Single dose oral aspirin for acute pain

BACKGROUND

Aspirin has been known to be an effective analgesic for many years and is commonly used throughout the world for many different pain conditions. It is important for both prescribers and patients to have the best possible information about the efficacy and safety of analgesics, and this need is reflected in patient surveys which show that postoperative pain is often poorly managed. We also need to benchmark relative efficacy and safety of current analgesics so that we can compare them with new analgesics.

OBJECTIVES

To quantitatively assess the analgesic efficacy and adverse effects of a single-dose of aspirin in acute pain of moderate to severe intensity.

SEARCH STRATEGY

Randomised trials were identified by searching Medline (1966 to March 1998), Embase (1980 to January 1998), the Cochrane Library (Issue 1,1998) and the Oxford Pain Relief Database (1950 to 1994).

SELECTION CRITERIA

The inclusion criteria used were: full journal publication, postoperative pain or a mixture of postoperative and acute trauma pain, oral administration, adult patients, baseline pain of moderate to severe intensity, double-blind design, and random allocation to treatment groups which compared aspirin with placebo.

DATA COLLECTION AND ANALYSIS

Summed pain relief or pain intensity difference over four to six hours was extracted, and converted into dichotomous information yielding the number of patients with at least 50% pain relief. This was then used to calculate the relative benefit and the number-needed-to-treat (NNT) for one patient to achieve at least 50% pain relief.

MAIN RESULTS

Seventy-two randomised single-dose trials met our inclusion criteria, with 3253 patients given aspirin, and 3297 placebo. Significant benefit of aspirin over placebo was shown for aspirin 600/650 mg, 1000 mg and 1200 mg, NNTs for at least 50% pain relief of 4.4 (4.0 to 4.9), 4.0 (3.2 to 5.4) and 2.4 (1.9 to 3.2) respectively. Single-dose aspirin 600/650 mg produced significantly more drowsiness and gastric irritation than placebo, with a number-needed-to-harm (NNH) of 28 (19 to 52) and 38 (22 to 174) respectively. Type of pain model, pain measurement, sample size, quality of study design, and study duration had no significant impact on the results.

REVIEWER'S CONCLUSIONS

Aspirin is an effective analgesic for acute pain of moderate to severe intensity with a clear dose-response. Drowsiness and gastric irritation were seen as significant adverse effects even though the studies were single-dose. The pain relief achieved with aspirin was very similar milligram for milligram to that seen with paracetamol.

Probes for narcotic receptor mediated phenomena. 26. Synthesis and biological evaluation of diarylmethylpiperazines and diarylmethylpiperidines as novel, nonpeptidic delta opioid receptor ligands

We recently reported (+)-4-¿(alphaR)-alpha-¿(2S,5R)-4-allyl-2, 5-dimethyl-1-piperazinyl¿-3-methoxybenzyl-N,N-diethylbenzamide (1b, SNC80) as a novel nonpeptidic delta receptor agonist and explored the structure-activity relationships (SAR) of a series of related derivatives. We have found that delta binding activities and selectivity showed little change when the 3-methoxy group in 1b was removed or replaced by the other substituents, whereas the N, N-diethylbenzamide group is important for interaction with the delta receptor. Extensive modification of the piperazine nucleus led to the synthesis of a new series of N, N-diethyl(alpha-piperazinylbenzyl)benzamides (2, 3a-e), N, N-diethyl(alpha-piperidinyl or piperidinylidenebenzyl)benzamides (4a, 5a-c, 6a-b), and related derivatives (4b, 7a-c). Several compounds (2, 3a, 3e, 6a) strongly bound to the delta receptor with K(i) values in the low nanomolar range. On the other hand, the binding affinities of these compounds for the mu and kappa receptors were negligible, indicating excellent delta opioid receptor subtype selectivity. The two nitrogen atoms on the piperazine nucleus showed different SAR in the interaction of this series of compounds at the delta receptor. Nitrogen N(4) appears to be an important structural element and is essential for electrostatic interaction, while N(1) seems to be unnecessary for recognition at the delta receptor.

Long-term follow-up of behavioural treatment for primary encopresis in people with intellectual disability in the community

Encopresis is a major problem in high-dependency fields such as intellectual disability. Little information is available with respect to either the prevalence or aetiology of encopresis, probably because it is widely regarded as part and parcel of the handicapping condition. Consequently, treatment reports are rare and confined to a small number of case studies. There is a dearth of long-term follow-up on the behavioural treatment of encopresis in the general population, and no long-term follow-up studies are available for the treatment of encopresis in intellectual disability. The present report provides follow-up data for nine out of 10 people with mainly severe intellectual disability who had received behavioural treatment for primary retentive or non-retentive encopresis between 5 and 17 years previously. Six out of the nine subjects for whom data were available were accident-free and a further two clients were very substantially improved. Interestingly, those whose former encopresis was retentive in nature maintained more successfully, despite the severity of their original impaction. The limitations of the present study are discussed.

Identification of a novel actin binding motif in smooth muscle myosin light chain kinase

Phosphorylation of the 20-kDa regulatory light chain of myosin catalyzed by a Ca(2+)/calmodulin-dependent myosin light chain kinase is important in the initiation of smooth muscle contraction and other contractile processes in non-muscle cells. It has been previously shown that residues 1-142 of smooth muscle myosin light chain kinase are necessary for high-affinity binding to actin-containing filaments in cells (1). To further localize the region of the kinase required for binding, a series of N-terminal deletion mutants as well as several N-terminal glutathione S-transferase fusion proteins were constructed. Cosedimentation assays showed that a peptide containing residues 1-75 binds to purified smooth muscle myofilaments. Furthermore, the N-terminal peptide was sufficient for high-affinity binding to actin stress fibers in smooth muscle cells in vivo. Alanine scanning mutagenesis in the fusion protein identified residues Asp-30, Phe-31, Arg-32, and Leu-35 as important for binding in vitro. There are two additional DFRXXL motifs located at residues 2-7 and 58-63. The DFR residues in these three motifs were individually replaced by alanine residues in the full-length kinase. Each of these mutations significantly decreased myosin light chain kinase binding to myofilaments in vitro, and each abolished high-affinity binding to actin-containing filaments in smooth muscle cells in vivo. These results identify a unique structural motif comprised of three repeat consensus sequences in the N terminus of myosin light chain kinase necessary for high-affinity binding to actin-containing filaments.

TISS and mortality after discharge from intensive care

OBJECTIVE

To examine the effect of high levels of pre-intensive care unit (ICU) discharge care, as assessed by the Therapeutic Intervention Scoring System (TISS), on subsequent hospital mortality.

DESIGN

A 1-year prospective, observational study.

SETTING

The ICU and wards of a university teaching hospital with no high dependency facility (HDU).

PATIENTS

A total of 283 patients were discharged to hospital wards between July 1997 and June 1998. ++

RESULTS

11 % of all ICU discharges subsequently died in hospital. Patients discharged with a TISS of 20 or greater had a 21.4 % mortality compared to 3.7 % for those with a TISS of less than 10. Increasing age, Acute Physiology Score (APS) on admission and male sex were also significantly associated with post-discharge death.

CONCLUSIONS

In a hospital without HDU facilities, patients who are receiving HDU levels of care on discharge from the ICU have a high in-hospital mortality.

Beta3-adrenergic receptor Trp64Arg polymorphism does not predict incident CHD or carotid intima-media thickness in a community-based sample of whites: the ARIC study. Atherosclerosis Risk in Communities

The beta3-adrenergic receptor (beta3-AR) is expressed in adipose tissue and plays a significant role in controlling energy expenditure through the regulation of lipolysis and thermogenesis. The possible clinical importance of the beta3-AR Trp64Arg polymorphism has prompted us to investigate the association between it and the extent of atherosclerosis and risk of incident coronary heart disease (CHD). The ability of the beta3-AR Trp64Arg polymorphism to predict the extent of atherosclerosis and incident CHD has been evaluated in participants of the Atherosclerosis Risk in Communities (ARIC) study. Incident CHD cases (n=271) were compared with a stratified random sample of the ARIC cohort (n=700). Comparisons were also made between a group with increased intimamedia thickness (IMT) of the carotid artery walls, but without prevalent CHD (n=324), and a thin-walled control group (n=407). The frequency of the Arg64 allele was 0.081 and 0.069 in the incident CHD cases and cohort sample, respectively, and 0.062 and 0.057 in the IMT cases and thin-walled controls, respectively. Comparison of incident CHD cases and the cohort sample by Cox proportional hazards modeling indicated that the Arg64 allele was not a significant predictor of incident CHD, either alone (RR=0.99, P=0.98) or after inclusion of body mass index (BMI) and fasting insulin and glucose measurements (RR=1.02, P=0.93). A comparison of IMT cases and thin-walled controls by multivariate logistic regression analysis suggested that the Arg64 allele was not a significant predictor of carotid artery intima-media thickness when evaluated alone (OR=1.32, P=0.29) or after BMI and fasting insulin and glucose measurements were added to the model (OR=1.28, P=0.35). We infer that the beta3-AR Trp64Arg polymorphism is not a major predictor of atherosclerosis or incident CHD in this sample of middle-aged white Americans.

If diabetes is a public health problem, why not treat it as one? A population-based approach to chronic illness

It is increasingly acknowledged that diabetes and other chronic illnesses are major public health problems. Medicare and many managed health care organizations have recognized the enormous personal and societal costs of uncontrolled diabetes in terms of complications, patient quality of life, and health care system resources. However, the current system of reactive acute-episode focused disease care practiced in many settings does not adequately address this public health problem. An alternative proactive, population-based approach to chronic illnesses such as diabetes is proposed and illustrated. This multilevel systems approach addresses supportive and inhibitory social-environmental factors at multiple levels (personal, family, health care team, work, neighborhood, community). Key disciplines contributing to a population-based approach to diabetes include epidemiology, behavioral science, health care services, public health, health economics, and quality of life professions. Current and potential contributions of each of these disciplines are illustrated and an integrative, population-based systems approach to diabetes management and prevention of complications is proposed. This approach is also seen as applicable to other chronic illnesses.

A process model of shiftwork and health

The authors developed and tested a process model of adaptation to shiftwork, which hypothesizes that various individual and situational variables influence the development of sleep and social and domestic disturbances. Both types of disturbances trigger various types of coping behavior, leading to several proximal outcomes. The end result is the development of chronic health problems in the form of digestive and cardiovascular symptoms. The model was tested with survey data collected from 2 samples of nurses (N = 1,532) in the United Kingdom and was cross-validated against a 3rd sample of industrial workers (N = 370). Results indicate support for the model across the 3 samples, although some sample-specific and subgroup effects were found. Results have direct implications for the development of shiftwork theory and interventions.

Adventitial expression of recombinant endothelial nitric oxide synthase gene reverses vasoconstrictor effect of endothelin-1

The present study was designed to determine the effect of recombinant endothelial nitric oxide synthase (eNOS) gene expression on reactivity of canine basilar arteries to endothelin-1 (ET-1). Experiments were performed ex vivo. The arteries were exposed (30 minutes at 37 degrees C) to adenoviral vectors encoding eNOS gene (AdCMVeNOS) or beta-galactosidase reporter gene (AdCMVbeta-Gal). Twenty-four hours after transduction, transgene expression was evident mainly in the vascular adventitia. Rings of control (nontransduced), AdCMVbeta-Gal- and AdCMVeNOS-transduced arteries with and without endothelium were suspended for isometric tension recording. Levels of guanosine 3',5'-cyclic monophosphate (cGMP) were measured by radioimmunoassay. During contractions to uridine 5'-triphosphate, ET-1 (10(-10) to 3x10(-9) mol/L) caused further increase in tension in control and AdCMVbeta-Gal-transduced arteries. In contrast, ET-1 caused concentration-dependent relaxations of AdCMVeNOS-transduced arteries. The relaxations to ET-1 in AdCMVeNOS-transduced arteries were endothelium-independent. They were abolished by N(G)-nitro-L-arginine methyl ester or by chemical treatment of adventitia with paraformaldehyde before gene transfer. ET-1 (10(-9) mol/L) significantly increased intracellular cGMP levels in AdCMVeNOS-transduced arteries without endothelium. In arteries transduced with AdCMVeNOS, higher concentrations (10(-9) to 3x10(-8) mol/L) of ET-2 also caused relaxations, whereas ET-3 and sarafotoxin, a selective ET(B) receptor agonist, did not produce any relaxations. The relaxations to ET-1 in AdCMVeNOS-transduced arteries were strongly reduced by BQ-123 (10(-7) mol/L), an ET(A) receptor antagonist, but were not affected by BQ-788 (3x10(-7) mol/L), an ET(B) receptor antagonist. These results suggest that genetically modified adventitia can produce nitric oxide and cause relaxations in response to ET-1 via activation of ET(A) receptors. Our findings support a novel concept that successful transfer and expression of recombinant eNOS gene can lead to a qualitative change in responsiveness to vasoconstrictor substances.

Suicidality in panic disorder: a comparison with schizophrenic, depressed, and other anxiety disorder outpatients

Recent findings by Weissman, Klerman, Markowitz, and Ouellette (1989) that subjects with panic disorder, with and without comorbid conditions, may be at increased risk for suicide attempts have been controversial. In an attempt to further investigate this finding, we utilized the original National Institute of Mental Health Epidemiological Catchment Area (ECA) suicide questions in an outpatient psychiatric clinic. We examined patients with panic disorder (n = 101). other anxiety disorders (n = 47), schizophrenia (n = 22). and major depression (n = 19). No significant differences were found among all four groups on any of the ECA suicide ideation questions. Only two (2%) of the panic disorder patients and none of the other groups made a suicide attempt in the past year. While 17% of patients with panic disorder and 9% of patients with other anxiety disorders reported having made a suicide attempt at some other time in their life, the schizophrenic (33%) and depressed groups (40%) reported significantly greater histories of suicide attempts. In a forward stepwise regression analysis for panic disorder patients, a history of substance abuse and comorbid depression predicted suicidality. The actual clinical risk for suicide attempts in panic disorder patients appears to occur when they suffer with comorbid diagnoses. These results highlight the need to aggressively treat panic disorder patients so they do not suffer the all-too-common sequelae of depression and substance abuse.

Dual energy X-ray absorptiometry assessment of fat mass distribution and its association with the insulin resistance syndrome

OBJECTIVE

To determine which dual energy X-ray absorptiometry (DXA)-derived indices of fat mass distribution are the most informative to predict the various parameters of the metabolic syndrome.

RESEARCH DESIGN AND METHODS

A total of 87 healthy men, 63 lean (% fat < or =26) and 24 obese (% fat >26), underwent DXA scanning to evaluate body composition with respect to the whole body and the trunk, leg, and abdominal regions from L1 to L4 and from L3 to L4. These regions were correlated with insulin sensitivity determined by the euglycemic-hyperinsulinemic clamp, insulin area under the curve after oral glucose tolerance test (AUC I); triglyceride; total, HDL, and LDL cholesterol; free fatty acids; and blood pressure. The analyses were performed in all subjects, as well as in lean and obese groups separately.

RESULTS

Among the various indices of body fat, DXA-determined adiposity in the abdominal cut at L1-4 level was the most predictive of the metabolic variables, showing significant relationships with glucose infusion rate ([GIR], mg kg(-1) lean body mass x min(-1)), triglyceride, and cholesterol, independent of total-body mass (r = -0.267, P<0.05; r = 0.316, P<0.005; and r = 0.319, P<0.005, respectively). Upon subanalysis, these correlations remained significant in lean men, whereas in obese men, only BMI and the amount of leg fat (negative relationship) showed significant correlations with triglyceride and cholesterol (r = 0.438, P<0.05; r = 0.458, P<0.05; r = -0.439, P<0.05; and r = -0.414, P<0.05, respectively). The results of a multiple regression analysis revealed that 47% of the variance in GIR among all study subjects was predicted by AUC I, fat L1-4, diastolic blood pressure (dBP), HDL, and triglyceride as independent variables. In the lean group, fat L1-4 alone accounted for 33% of the variance of GIR, whereas in obese men, AUC I and dBP explained 68% of the variance in GIR.

CONCLUSIONS

The DXA technique applied for the evaluation of fat distribution can provide useful information regarding various aspects of the insulin resistance syndrome in healthy subjects. DXA can be a valid, accurate, relatively inexpensive, and safer alternative compared with other methods to investigate the role of abdominal body fat distribution on cardiovascular risk factors.

A process model of shiftwork and health

The authors developed and tested a process model of adaptation to shiftwork, which hypothesizes that various individual and situational variables influence the development of sleep and social and domestic disturbances. Both types of disturbances trigger various types of coping behavior, leading to several proximal outcomes. The end result is the development of chronic health problems in the form of digestive and cardiovascular symptoms. The model was tested with survey data collected from 2 samples of nurses (N = 1,532) in the United Kingdom and was cross-validated against a 3rd sample of industrial workers (N = 370). Results indicate support for the model across the 3 samples, although some sample-specific and subgroup effects were found. Results have direct implications for the development of shiftwork theory and interventions.