Innovative models of healthcare delivery: an umbrella review of reviews

OBJECTIVE

To undertake a synthesis of evidence-based research for seven innovative models of care to inform the development of new hospitals.

DESIGN

Umbrella review.

SETTING

Interventions delivered inside and outside of acute care settings.

PARTICIPANTS

Children and adults with one or more identified acute or chronic health conditions.

DATA SOURCES

PsycINFO, Ovid MEDLINE and CINAHL.

PRIMARY AND SECONDARY OUTCOME MEASURES

Clinical indicators and mortality, healthcare utilisation, quality of life, self-management and self-care and patient knowledge.

RESULTS

A total of 66 reviews were included, synthesising evidence from 1272 primary studies across the 7 models of care. Virtual care was the most common model studied, addressed by 47 (73%) of the reviews. Common outcomes evaluated across reviews were clinical indicators and mortality, healthcare utilisation, self-care and self-management, patient knowledge, quality of life and cost-effectiveness. The findings indicate that the innovative models of healthcare we identified in this review may be effective in managing patients with a range of acute and chronic conditions. Most of the included reviews reported evidence of comparable or improved care.

CONCLUSIONS

A consideration of local infrastructure and individual patient characteristics, such as health literacy, may be critical in determining the suitability of models of care for patients and their implementation in local health systems.

TRIAL REGISTRATION NUMBER

10.17605/OSF.IO/PS6ZU.

Particle size as a driver of dewatering performance and its relationship to stabilization in fecal sludge

Poor and unpredictable dewatering performance of fecal sludge is a major barrier to sanitation provision in urban areas not served by sewers. Fecal sludge comprises everything that accumulates in onsite containments, and its characteristics are distinct from wastewater sludges and from feces. There is little fundamental understanding of what causes poor dewatering in fecal sludge. For the first time, we demonstrate that particle size distribution is a driver of dewatering performance in fecal sludge, and is associated with level of stabilization. Higher concentrations of small particles (<10 μm) and smaller median aggregate size (D50) corresponded to poor dewatering performance (measured by capillary suction time (CST) and supernatant turbidity) in field samples from Kenya and Uganda and in controlled laboratory anaerobic storage experiments. More stabilized fecal sludge (higher C/N, lower VSS/TSS) had better dewatering performance, corresponding to lower concentrations of small particles. Samples with the largest aggregates (D50 > 90 μm) had higher abundance of Gammaproteobacteria Pseudomonas, and samples with the smallest aggregates (D50 ≤ 50 μm) were characterized by higher abundance of Bacteroidetes Vadin HA17 and Rikenellaceae. Contrary to common perceptions, stabilization, particle size distribution, and dewatering performance were not dependent on time intervals between emptying of onsite containments or on time in controlled anaerobic storage experiments. Our results suggest that the stabilization process in onsite containments, and hence the dewaterability of sludge arriving at treatment facilities, is not dependent on time in containment but is more likely associated with specific microbial populations and the in-situ environmental conditions which promote or discourage their growth.

Inactivation of the bacterial pathogens Staphylococcus pseudintermedius and Acinetobacter baumannii by butanoic acid

AIMS

This study was performed to evaluate the efficacy of butanoic acid against bacterial pathogens including Acinetobacter baumannii and Staphylococcus pseudintermedius.

METHODS AND RESULTS

Vegetative bacteria were exposed to butanoic acid in vitro and log reduction was quantified using viable count assays. The maximum (8 and 9) log inactivation was determined by qualitatively assaying for growth/no-growth after a 48-h incubation (37°C). Membrane integrity after exposure to butanoic acid was determined by propidium iodide staining, scanning electron microscopy, membrane depolarization and inductively coupled plasma analysis. Cytosolic pH was measured by 5-(6-)carboxyfluorescein succinimidyl ester.

CONCLUSIONS

Inhibitory concentrations of butanoic acid ranged between 11 and 21 mmol l^-1 for Gram-positive and Gram-negative species tested. The maximum log reduction of A. baumannii was achieved with a 10-s exposure of 0·50 mol l^-1 of butanoic acid. Staphylococcus pseudintermedius required 0·40 mol l^-1 of butanoic acid to achieve the same level of reduction in the same time period. Inactivation was associated with membrane permeability and acidification of the cytosol.

SIGNIFICANCE AND IMPACT OF THE STUDY

Antibiotic resistance among bacterial pathogens necessitates the utilization of novel therapeutics for disinfection and biological control. These results may facilitate the development of butanoic acid as an effective agent against a broad-spectrum of antibiotic-resistant bacterial pathogens.

Autologous bilayered self-assembled skin substitutes (SASSs) as permanent grafts: a case series of 14 severely burned patients indicating clinical effectiveness

Split-thickness skin autografts (AGs) are the standard surgical treatment for severe burn injuries. However, the treatment of patients with substantial skin loss is limited by the availability of donor sites for skin harvesting. As an alternative to skin autografts, our research group developed autologous self-assembled skin substitutes (SASSs), allowing the replacement of both dermis and epidermis in a single surgical procedure. The aim of the study was to assess the clinical outcome of the SASSs as a permanent coverage for full-thickness burn wounds. Patients were recruited through the Health Canada's Special Access Program. SASSs were grafted on debrided full-thickness wounds according to similar protocols used for AGs. The graft-take and the persistence of the SASS epithelium over time were evaluated. 14 patients received surgical care with SASSs. The mean percentage of the SASS graft-take was 98 % (standard deviation = 5) at 5 to 7 d after surgery. SASS integrity persisted over time (average follow-up time: 3.2 years), without noticeable deficiency in epidermal regeneration. Assessment of scar quality (skin elasticity, erythema, thickness) was performed on a subset of patients. Non-homogeneous pigmentation was noticed in several patients. These results indicated that the SASS allowed the successful coverage of full-thickness burns given its high graft-take, aesthetic outcome equivalent to autografting and the promotion of long-term tissue regeneration. When skin donor sites are in short supply, SASSs could be a valuable alternative to treat patients with full-thickness burns covering more than 50 % of their total body surface area.

Hepatitis B surface antigen loss and sustained viral suppression in Asian chronic hepatitis B patients: A community-based real-world study

Community-based real-world outcomes on effectiveness of antiviral therapies for chronic hepatitis B virus (CHB) in Asians are limited. Whether hepatitis B surface antigen (HBsAg) loss correlates with undetectable virus and alanine aminotransferase (ALT) normalization on treatment or what predicts risk of seroreversion or detectable virus after stopping therapy is unclear. We aim to evaluate rates and predictors of HBsAg loss, seroconversion, ALT normalization and undetectable HBV DNA, including HBsAg seroreversion or re-emergence of HBV DNA among Asian CHB patients. We retrospectively evaluated 1072 CHB adults on antiviral therapy at two community gastroenterology clinics from 1997 to 2015. Rates of HBsAg loss, ALT normalization, achieving undetectable HBV DNA and developing surface antibody (anti-HBs) were stratified by HBeAg status. Following HBsAg loss, HBsAg seroreversion or re-emergence of detectable HBV DNA was analysed. With median treatment of 76.7 months, the overall rate of HBsAg loss was 4.58%, with similar HBsAg loss rates between HBeAg-positive and HBeAg-negative patients (4.44% vs 4.71%, P=.85) in a predominantly Asian population (98.1%). Among HBsAg loss patients, 33.3% developed anti-HBs, 95.8% achieved undetectable virus and 66.0% normalized ALT. No significant baseline or on-treatment predictors of HBsAg loss were observed. While six patients who achieved HBsAg loss had seroreversion with re-emergence of HBsAg positivity, viral load remained undetectable, demonstrating the sustainability of viral suppression. Among a large community-based real-world cohort of Asian CHB patients treated with antiviral therapy, rate of HBsAg loss was 4.58%. Despite only 33.3% of HBsAg loss patients achieving anti-HBs, nearly all patients achieved sustained undetectable virus.

Community-based real-world treatment outcomes of sofosbuvir/ledipasvir in Asians with chronic hepatitis C virus genotype 6 in the United States

Sofosbuvir/ledipasvir (SOF/LDV) is the first all-oral ribavirin-free treatment approved for chronic hepatitis C virus (HCV) genotype 6, offering a safe and highly efficacious treatment option. Large studies evaluating real-world outcomes of this regimen are lacking. We aim to evaluate real-world treatment outcomes for HCV genotype 6. A retrospective cohort study evaluated 65 adults (age ≥18) with chronic HCV genotype 6 treated with SOF/LDV without ribavirin at a community gastroenterology clinic in the United States from November 2014 to May 2016. Rates of undetectable virus at week 4 on treatment, at end of treatment (EOT) and SVR12 were stratified by the presence of cirrhosis and prior treatment (treatment naïve vs treatment experienced). Among 65 patients with chronic HCV genotype 6 treated with SOF/LDV (52.3% male, mean age 66.3 years [SD 9.7], 41.5% cirrhosis and 15.4% treatment experienced), 97.3% had undetectable virus at week 4 on treatment, 96.9% had undetectable virus at EOT and 95.3% achieved SVR12. SVR12 was 100% in females vs 91.2% in males, P=.096, and 92.3% in patients with cirrhosis vs 97.4% in those without cirrhosis, P=.347. Resistance testing of treatment failures was attempted but unsuccessful due to lack of conforming primers to define the possible resistance mutations. Among the largest U.S. community-based real-world cohort of Asian chronic HCV genotype 6 patients treated with all-oral SOF/LDV without ribavirin, SVR12 was similar to SVR12 reported in clinical trials, confirming the safety and effectiveness of this regimen and validating current HCV genotype 6 treatment guideline recommendations.

Arterial stiffness is elevated in normotensive type 2 diabetic patients with peripheral neuropathy

BACKGROUND AND AIMS

Arterial stiffness, a measure of macrovascular damage predictive of poor cardio-vascular outcomes, is strongly related to age and hypertension (HT). In diabetic patients peripheral neuropathy (PN) has been found to be associated with increased arterial stiffness, which might be due to the concomitant presence of HT. The aim of this study was to examine in type-2 diabetic patients, the relationship between arterial stiffness and presence or absence of PN and HT separately.

METHODS AND RESULTS

Arterial stiffness was measured with the gold standard carotid-femoral pulse wave velocity (PWV) in 447 type-2 diabetic subjects of whom 66% were hypertensive, 53% had PN, and 40% had both. Patients with PN were older, more often hypertensive and had higher PWV than those free of PN. Patients were separated according to the presence or absence of PN and HT. PWV values above the 90th percentile age- and blood pressure-adjusted reference range (PWV+) were different across these groups (p < 0.005) with the following respective prevalences: 27.2%, 53.4%, 33.3% and 30.6%. Only PWV+ was significantly associated with PN and hypertension in the interaction analysis.

CONCLUSION

Well controlled hypertensive patients did not have elevated arterial stiffness compared to normotensive patients. This might be due to anti-hypertensive treatment although our study design does not allow us to confirm it. A strong association between PN and arterial stiffness was only present in normotensive patients, suggesting that normotensive type 2 diabetic patients with PN and elevated arterial stiffness should be carefully managed to prevent future macrovascular complications.

The clinical utility of whole-exome sequencing in the context of rare diseases - the changing tides of medical practice

Whole-exome sequencing (WES) carries the potential to facilitate the identification of disease causing genes. This is particularly relevant concerning rare diseases, which proves particularly difficult for physicians to diagnose. However, the complexity of this technology renders its applicability onto the clinical setting uncertain. Our study thus aims to understand physicians' perspectives regarding the clinical utility of WES, particularly for providing a diagnosis for patients with rare diseases. Ten semi-structured interviews were conducted with physicians with experience and familiarity with WES, and the major themes that emerged from our interviews were (i) the relevance of WES in diagnosing patients with rare diseases (appropriateness); (ii) the cost-effectiveness of WES (accessibility), (iii) the practical issues related to the clinical implementation of WES (practicability); and (iv) ethical, legal and social issues (acceptability). Our study highlights how the clinical implementation of WES presents additional challenges where rare diseases are taken into consideration.

Decreased stroke volume−brachial pulse pressure ratio in patients with type 2 diabetes over 50 years: the role of peripheral neuropathy

BACKGROUND AND AIMS

To document the stroke volume to pulse pressure ratio (SV/PP, an index of total arterial compliance) and its correlates in patients with type 2 diabetes (T2DM) aged over 50 years whose peripheral neuropathy and silent myocardial ischemic (SMI) status were known.

METHODS AND RESULTS

A total of 360 patients with T2DM aged ≥ 50 years, without cardiac history or symptom, left ventricular systolic dysfunction, dilatation and hypokinesia, were retrospectively enrolled. The SV/PP was calculated from echocardiographic left ventricular measurements and brachial blood pressure at rest. Peripheral neuropathy was defined as the presence of any two or more of the following: neuropathic symptoms, decreased distal sensation, or decreased or absent ankle reflexes. SMI was defined as an abnormal stress myocardial scintigraphy and/or stress echocardiography. A low SV/PP ratio (<0.53 ml/m²/mmHg, first tertile) was associated with age, creatinine clearance, 24 h urinary albumin excretion rate, peripheral neuropathy, hypertension, serum total cholesterol and triglycerides levels (p < 0.05-0.0001). In multivariate analysis, age (OR 1.1 [1.0-1.2], p < 0.01), triglycerides (OR 1.5 [1.2-2.0], p = 0.01) and peripheral neuropathy (OR 2.2 [1.2-3.9], p = 0.009) were independently associated with a low SV/PP. The patients with peripheral neuropathy had lower SV (p < 0.01) and higher PP (p < 0.05) than those without, and only lower SV after adjustment for age and nephropathy. Similar results were obtained in the patients with and without SMI.

CONCLUSION

Peripheral neuropathy was independently associated with decreased SV/PP, mainly through decreased SV, in patients with T2DM over 50 years.

Hsp90 chaperones PPARγ and regulates differentiation and survival of 3T3-L1 adipocytes

Adipose tissue dysregulation has a major role in various human diseases. The peroxisome proliferator-activated receptor-γ (PPARγ) is a key regulator of adipocyte differentiation and function, as well as a target of insulin-sensitizing drugs. The Hsp90 chaperone stabilizes a diverse set of signaling 'client' proteins, thereby regulates various biological processes. Here we report a novel role for Hsp90 in controlling PPARγ stability and cellular differentiation. Specifically, we show that the Hsp90 inhibitors geldanamycin and novobiocin efficiently impede the differentiation of murine 3T3-L1 preadipocytes. Geldanamycin at higher concentrations also inhibits the survival of both developing and mature adipocytes, respectively. Further, Hsp90 inhibition disrupts an Hsp90-PPARγ complex, leads to the destabilization and proteasomal degradation of PPARγ, and inhibits the expression of PPARγ target genes, identifying PPARγ as an Hsp90 client. A similar destabilization of PPARγ and a halt of adipogenesis also occur in response to protein denaturing stresses caused by a single transient heat-shock or proteasome inhibition. Recovery from stress restores PPARγ stability and adipocyte differentiation. Thus, our findings reveal Hsp90 as a critical stress-responsive regulator of adipocyte biology and offer a potential therapeutic target in obesity and the metabolic syndrome.

The report of male gender and retinopathy status improves the current consensus guidelines for the screening of myocardial ischemia in asymptomatic type 2 diabetic patients

BACKGROUND AND AIMS

American Diabetes Association (ADA), French-speaking Societies for diabetes & cardiology (ALFEDIAM-SFC) and Cardiac Radionuclide Imaging (CRI) have proposed guidelines for the screening of silent myocardial ischemia (SMI). The aim of the study was to evaluate their diagnostic values and how to improve them.

METHODS AND RESULTS

731 consecutive type 2 diabetic patients with ≥1 additional risk factor were screened between 1992 and 2006 for SMI by stress myocardial scintigraphy and for silent coronary artery disease (CAD) by coronary angiography. A total of 215 (29.4%) patients had SMI, and 79 of them had CAD. ADA (Odds Ratio 1.7 [95% Confidence Interval: 1.2-2.5]; p < 0.05), ALFEDIAM-SFC (OR 1.5 [1.0-2.5], p < 0.05) and CRI criteria (OR 2.0 [1.4-2.8], p < 0.01) predicted SMI. Considering the presence of male gender and retinopathy added to the prediction of SMI allowed by ADA criteria (c statistic: area under the curve AROC 0.651 [0.605-0.697] versus 0.582 [0.534-0.630]), p < 0.01 and ALFEDIAM-SFC criteria (AROC 0.672 [0.620-0.719] versus 0.620 [0.571-0.670], p < 0.05). CRI prediction of SMI was improved by considering the presence of macroproteinuria and retinopathy (AROC 0.621 [0.575-0.667] versus 0.594 [0.548-0.641], p < 0.01). Severe retinopathy (OR 3.4 [1.2-9.4], p < 0.05), smoking habits (OR 2.1 [1.1-4.2], p < 0.05) and triglyceride levels (OR 1.3 [1.0-1.6], p < 0.05) were independent predictors of CAD in the patients with SMI.

CONCLUSION

Current guidelines criteria are able to predict SMI but prediction may be improved by considering male gender and the presence of retinopathy. CAD is more frequent in the patients with SMI who are current smokers, have severe retinopathy and higher triglyceride levels.

Energy level diagram and kinetics of luminescence of Ag nanoclusters dispersed in a glass host

A site-selective spectroscopy study of Ag nanoclusters dispersed in oxyfluoride glass hosts has been carried out. The nano- to millisecond, essentially non-exponential, luminescence kinetics of Ag nanoclusters has been detected in the spectral range from 450 to 1000 nm, when excited at discrete wavelengths in the range 250 to 450 nm. Based on these experimental observations, the energy level configuration coordinate diagram for the involved ground and excited singlet/triplet states of the Ag nanoclusters has been proposed and confirmed by the density functional theory (DFT). The sites for the Ag nanoclusters are argued to be multiple. The structure/geometry of the involved Ag nanoclusters has been suggested to involve spin-paired dimers Ag²⁺, or tetramers Ag₄²⁺, with a varying elongation/distortion along the tetramer diagonals.

Structural identification of caged vanadium doped silicon clusters

The geometry of cationic silicon clusters doped with vanadium, Si(n)V(+) (n=12-16), is investigated by using infrared multiple photon dissociation of the corresponding rare gas complexes in combination with ab initio calculations. It is shown that the clusters are endohedral cages, and evidence is provided that Si(16)V(+) is a fluxional system with a symmetric Frank-Kasper geometry.

What would be the outcome if the American Diabetes Association recommendations of 2010 had been followed in our practice in 1998-2006?

AIMS

In 2010, the American Diabetes Association has published recommendations on the population to be screened for dysglycaemia; the diagnostic criteria for intermediate hyperglycaemia and diabetes using oral glucose tolerance testing and HbA(1c); and the patients eligible for treatment with metformin. We aimed to evaluate the consequences of screening with oral glucose tolerance test or HbA(1c) in an at-risk population.

METHODS

Among 1177 overweight or obese consecutive adults without known diabetes who were referred to our department for weight management, we selected 1157 individuals (83% female; 80% European) fulfilling the American Diabetes Association 2010 criteria for dysglycaemia screening.

RESULTS

Mean age was 41.2 ± 13 years, BMI 37.0 ± 7.2 kg/m(2), fasting plasma glucose 4.9 ± 0.8 mmol/l and HbA(1c) (turbidimetric immunoassay) 5.7 ± 0.7% (39 mmol/mol). Based on oral glucose tolerance test and HbA(1c), respectively, 76 (6.6%) and 113 (9.8%) patients had diabetes, including 34 sharing both criteria; 307 (26.5%) and 478 (41.3%) had intermediate hyperglycaemia; and 130 (11.2%) and 255 (22.0%) would be treated with metformin. The sensitivity/specificity of HbA(1c) ≥ 6.5% (48 mmol/mol) for the diagnosis of diabetes according to the oral glucose tolerance test were 44.7/92.7%. Diabetes risk scores and UK Prospective Diabetes Study cardiovascular risk score were the highest in the 130 patients having both an abnormal oral glucose tolerance test and HbA(1c) ≥ 5.7%.

CONCLUSIONS

In a population at risk for diabetes, the HbA(1c) strategy could lead to diagnosing more cases of dysglycaemia and to treating more patients with metformin than the oral glucose tolerance test strategy. The consistency of either diagnostic criteria was low. The patients with the highest a priori risk of diabetes and cardiovascular disease were those fulfilling both oral glucose tolerance test and HbA(1c) criteria.

N-terminal pro-B-type natriuretic peptide: an independent marker for coronary artery disease in asymptomatic diabetic patients

AIMS

To determine whether plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, a marker for cardiac failure and potentially for the severity of coronary artery disease (CAD), predicts silent myocardial ischaemia (SMI) and silent CAD in asymptomatic high-risk diabetic patients.

METHODS

Five hundred and seventeen asymptomatic diabetic patients with > or = 1 additional cardiovascular risk factor but without heart failure were prospectively screened between 1998 and 2008 for SMI, defined as an abnormal stress myocardial scintigraphy, and subsequently for significant (> 70%) angiographic CAD. The 323 patients with interpretable echocardiography and for whom NT-proBNP was measured were included in this analysis.

RESULTS

SMI was found in 108 (33.4%) patients, 39 of whom had CAD. NT-proBNP was higher in the patients with CAD than in the patients without CAD [45.0 (1-3199) vs. 20.0 (1-1640) pg/ml; P < 0.0001 median (range)], even after adjustment for confounding factors: age, gender, body mass index, glycated haemoglobin (HbA(1c)), retinopathy, nephropathy, hypertension, echocardiographic parameters (P < 0.05). NT-proBNP in the third tertile (> or = 38 pg/ml) predicted CAD with a sensitivity of 59% and a specificity of 67%. In a multiple logistic regression analysis including NT-proBNP > or = 38 pg/ml, age, body mass index, gender, HbA(1c), hypertension, retinopathy, nephropathy, peripheral occlusive arterial disease, left ventricular systolic dysfunction, dilatation and hypertrophy and Type 1 transmitral flow, NT-proBNP > or = 38 pg/ml was the only significant independent predictor of silent CAD [odds ratio (OR) 3.1 (95% confidence interval 1.3-7.6), P = 0.015].

CONCLUSIONS

NT-proBNP measurement helps to better define asymptomatic diabetic patients with an increased likelihood for CAD, independently of cardiac function and structure.

Bouc-Wen model parameter identification for a MR fluid damper using computationally efficient GA

A non-symmetrical Bouc-Wen model is proposed in this paper for magnetorheological (MR) fluid dampers. The model considers the effect of non-symmetrical hysteresis which has not been taken into account in the original Bouc-Wen model. The model parameters are identified with a Genetic Algorithm (GA) using its flexibility in identification of complex dynamics. The computational efficiency of the proposed GA is improved with the absorption of the selection stage into the crossover and mutation operations. Crossover and mutation are also made adaptive to the fitness values such that their probabilities need not be user-specified. Instead of using a sufficiently number of generations or a pre-determined fitness value, the algorithm termination criterion is formulated on the basis of a statistical hypothesis test, thus enhancing the performance of the parameter identification. Experimental test data of the damper displacement and force are used to verify the proposed approach with satisfactory parameter identification results.

Letter: OCCO*+, NNCO*+ and NNNN*+ radical cations

Chemical ionization of a mixture of nitrogen and carbon monoxide produces three stable isobaric species at m/z 56: OCCO, OCNN and NNNN radical cations. Separated at increased resolution, these ions are readily identified by collisional activation. Neutralization-reionization experiments performed on two different mass spectrometers have not allowed the detection of any recovery signals for the corresponding neutrals.

Quenching of the magnetic moment of a transition metal dopant in silver clusters

Single magnetic atoms embedded in a nonmagnetic host exhibit the Kondo effect in the bulk limit, while in very small molecules the magnetic atom is hardly affected by the matrix. In a combined theoretical (density functional theory) and experimental (photofragmentation and mass spectrometry) study we consider the intermediate case of nanometer sized transition-metal-doped silver clusters. In particular, we provide experimental evidence for enhanced stability of the cobalt-doped silver cluster Ag10Co+ and show theoretically that it has a symmetric endohedral geometry with a closed 18-electron singlet electronic shell structure. This implies that the magnetic moment on the cobalt atom is quenched.

Ab initio study of small graphitic cones with triangle, square, and pentagon apex

Accurate geometries of carbon nanocones of different sizes with a triangle, square or pentagon at the apex have been determined for the first time using a quantum chemical optimization method. The structure close to the apex is distorted from an ideal conical surface. The charging effect of the central defect is quite different from that predicted by tight-binding calculations. The symmetry behavior of the frontier orbitals and the size of the highest occupied molecular orbital-lowest unoccupied molecular orbital gap versus cone type and size is explained. The density of states quickly converges towards that of graphite when the size of the cone increases. In comparison to previous results in the literature it is found that the local densities of states of cones, that are locally different but belong to the same topo-combinatoric class, share common features.

Comparative study on pressure and temperature stability of 5-methyltetrahydrofolic acid in model systems and in food products

A comparative study on the pressure and temperature stability of 5-methyltetrahydrofolic acid (5-CH(3)-H(4)folate) was performed in model/buffer systems and food products (i.e., orange juice, kiwi puree, carrot juice, and asparagus). Effects of pH and ascorbic acid (0.5 mg/g) on 5-CH(3)-H(4)folate stability in buffer systems were studied on a kinetic basis at different temperatures (from 65 to 160 degrees C) and different pressure/temperature combinations (from 100 to 700 MPa/from 20 to 65 degrees C). These studies showed that (i) the degradation of 5-CH(3)-H(4)folate in all model systems could be described by first-order reaction kinetics, (ii) the thermostability of 5-CH(3)-H(4)folate was enhanced by increasing pH up to 7, (iii) 5-CH(3)-H(4)folate was relatively pressure stable at temperatures lower than 40 degrees C, and (iv) ascorbic acid enhanced both the thermo- and barostabilities of 5-CH(3)-H(4)folate. In food products, temperature and pressure stabilities of 5-CH(3)-H(4)folate were studied at different temperatures (70-120 degrees C) and different pressure/temperature combinations (from 50 to 200 MPa/25 degrees C and 500 MPa/60 degrees C). 5-CH(3)-H(4)folate in orange juice and kiwi puree was relatively temperature (up to 120 degrees C) and pressure (up to 500 MPa/60 degrees C) stable in contrast to carrot juice and asparagus. Addition of ascorbic acid (0.5 mg/g) in carrot juice resulted in a remarkable protective effect on pressure (500 MPa/60 degrees C/40 min) and temperature degradation (120 degrees C/40 min) of 5-CH(3)-H(4)folate.

Demographic trends in Vietnam

"Asia's four ¿little dragons' (South Korea, Hong Kong, Singapore and Taiwan) have in common not only an economic boom, but also the same rapid demographic transition. How does Vietnam, whose economy is poised for a take-off, stand in this respect? In an attempt to answer this question, [the authors] study the growing corpus of information which a number of ad hoc surveys have added to the 1979 and 1989 population censuses."

Pediatric imaging: sedation with an injection formulation modified for rectal administration

PURPOSE

To determine if rectal sedation with thiopental sodium produced for intravenous administration provides safe and effective sedation for children undergoing diagnostic imaging.

MATERIALS AND METHODS

Five hundred twenty-five consecutive children (mean age, 2.7 years +/- 2.2 [SD]) underwent magnetic resonance imaging (n = 425), computed tomography (n = 89), and nuclear medicine (n = 11) examinations after rectal administration of thiopental sodium injection solution. The solution was prepared from thiopental sodium powder mixed with sterile water to create a concentration of 100 mg/mL. The dose ranged from 25 to 40 mg per kilogram of body weight, with a total dose limit of 1.5 g. The percentages of successful sedations and adverse reactions were evaluated on the basis of data collected at the time of the sedation.

RESULTS

Sedation was successful in 504 (96%) children. Ten (2%) children experienced desaturation, but only three of the 10 experienced sedation failure. All cases of desaturation were treated successfully with head repositioning, administration of supplemental oxygen, or both. No children experienced vomiting, acute rectal irritation, paradoxical hyperactivity, or prolonged sedation.

CONCLUSION

Thiopental sodium sedation for pediatric imaging, with use of a rectal solution prepared from thiopental sodium preparation for intravenous injection, is safe and effective.

Receptors for prostaglandin E(2) that regulate cellular immune responses in the mouse

Production of prostaglandin E(2) (PGE(2)) is enhanced during inflammation, and this lipid mediator can dramatically modulate immune responses. There are four receptors for PGE(2) (EP1-EP4) with unique patterns of expression and different coupling to intracellular signaling pathways. To identify the EP receptors that regulate cellular immune responses, we used mouse lines in which the genes encoding each of the four EP receptors were disrupted by gene targeting. Using the mixed lymphocyte response (MLR) as a model cellular immune response, we confirmed that PGE(2) has potent antiproliferative effects on wild-type responder cells. The absence of either the EP1 or EP3 receptors did not alter the inhibitory response to PGE(2) in the MLR. In contrast, when responder cells lacked the EP2 receptor, PGE(2) had little effect on proliferation. Modest resistance to PGE(2) was also observed in EP4-/- responder cells. Reconstitution experiments suggest that EP2 receptors primarily inhibit the MLR through direct actions on T cells. Furthermore, PGE(2) modulates macrophage function by activating the EP4 receptor and thereby inhibiting cytokine release. Thus, PGE(2) regulates cellular immune responses through distinct EP receptors on different immune cell populations: EP2 receptors directly inhibit T cell proliferation while EP2 and EP4 receptors regulate antigen presenting cells functions.

Nitrous oxide as a 1,3-dipole: a theoretical study of its cycloaddition mechanism

The 1,3-dipolar cycloadditions of nitrous oxide and substituted alkynes have been studied at the B3LYP/6-31G(d,p) level. The reaction is controlled by LUMO (dipole)--HOMO (dipolarofile) and involves aromatic transition structures. The shape of the potential energy surface and the regioselectivity are not affected by the polarity of the solvents, except in the case of N2O + HC triple bond CSiH3. Different reactivity criteria including FMO coefficients product C, local softness differences Delta, magnetic susceptibility anisotropy chi(anis), and nucleus-independent chemical shifts NICS were used to predict the regioselectivity in all studied cases; the C, Delta criteria turn out to give the best results among them. The aromaticity of the transition structure is not a factor in determining the regiochemistry of the cycloaddtition reactions.

Mechanism of the ring-chain rearrangement in phosphiranes: hydrogen versus halogen migration

Ab initio quantum chemical calculations including HF, MP2, CCSD(T), CASSCF(10,10)/CASPT2, and B3LYP methods with the 6-31G(d,p) basis set were used to probe the mechanism of the ring-chain rearrangement of halogeno-phosphiranes. It is confirmed that the lowest energy interconversion between C-halogenated-(X)-phosphiranes and vinylphosphines, with X = H, F, Cl, and Br, is a one-step process in which the C-P bond cleavage and X-sigmatropic migration from C to P occur in a concerted manner in a single transition structure. The migration of a hydrogen from CH(H) is slightly favored over that of CX(H), and thus, the cleavage of the C(X)-P bond is preferred. The energy barrier for the whole process involving hydrogen migration in the parent phosphirane is calculated to be about 45 +/- 5 kcal/mol. The migratory aptitude of the atoms X in the uncomplexed species is found as follows: H > Br > Cl > F, either in the gaseous phase or in aqueous and DMSO solutions. The solvation enthalpies that were estimated using a polarizable continuum model (PCM) are rather small and do not modify the relative ordering of the energy barriers. Such a trend is at variance with recent experimental findings on metal-phosphinidene complexes in which only halogen migration was observed. This might arise from a peculiar effect of the metal fragments W(CO)(5) used in the experimental studies to stabilize the phosphorus species that induce a quite different mechanism. Calculations of the (31)P chemical shifts using the GIAO/B3LYP/6-311+G(d,p) method show a remarkable correlation between the delta(31)P(X) chemical shifts of X-phosphiranes and those of X-phosphines (XCH(2)PH(2)), suggesting that the large beta substituent effect is not inherent to the small rings.

Magnification views of mammography decrease biopsy rates

Mammography is a valuable tool for screening and has increased early detection of breast cancer. Magnification views are commonly used to further elucidate suspicious changes seen on routine mammograms. The effect of magnification views and their utility have not been studied regarding the influence on treatment strategies. All patients who had magnification views performed along with their mammogram at Tulane University Medical Center over a one-year period were included. Patient charts were reviewed for mammogram readings, recommendations, and any biopsy results. The original mammograms without the magnification views were given to a physician who was blinded to the final results of the magnification views for a recommendation of whether or not to biopsy the lesion. These recommendations were compared with the results with actual recommendations. Magnification views were performed on 127 patients. After the additional magnification views were taken 27 per cent (34 of 127) of patients had biopsies performed. Biopsy results revealed benign findings in 71 per cent and nonbenign findings (lobular carcinoma in situ, ductal carcinoma in situ, or carcinoma) in 29 per cent. On the basis of the recommendations without magnification views 64 per cent of patients would have had biopsies performed. Magnification views decreased the biopsy rates by 58 per cent (P < 0.001; chi2 tests). Magnification views can help decrease the number of biopsies performed for suspicious small areas on mammograms. Their judicious use can help decrease unnecessary procedures, patient anxiety, and cost. Magnification views are useful to help surgeons and radiologists best screen for breast cancer.

Theoretical Study of [2 + 1] cycloaddition of CO and CS to acetylenes forming cyclopropenones and cyclopropenethiones

The [2 + 1] cycloadditions of carbon monoxide and carbon monothioxide CX (X = O, S) to acetylenes (R1C triple bond CR2 with R1 = H, OH and R2 = CH3, OH, NH2, C6H5) have been studied at the B3LYP/6-311G(d,p) level. It has been shown that the reaction proceeds in two steps forming first an intermediate having the properties of both a carbene and a zwitterion followed by a ring closure leading to cyclopropenones or cyclopropenethiones. The solvent effect does not play an important role in the course of the cycloaddition. The estimation of the first vertical excitation energies by CIS and TD-B3LYP methods shows that the reactions likely take place in the ground state rather than in an excited state. All the studied cyclopropenones and cyclopropenethiones are aromatic as shown by their NICS values and confirmed by calculated and experimental NMR chemical shifts. Different reactivity criteria including HOMO coefficient, local softness, hardness, polarizability, and NICS are used to predict the site selectivity in all studied cases, and the NICS criterion seems to yield the best results among them.

High-energy collisional activation of the molecular ions of thiophene-2-one with different target gases

Collisional activation of keV thiophene-2-one radical cations 1(+*) with O(2) or NO(*) as the target gas leads to a desulfuration reaction. This peculiar reaction is insignificant or absent with other targets such as helium, argon, methane or nitrogen. The radical cations produced in this desulfuration reaction are most probably vinylketene ions, as indicated by a triple mass spectrometric (MS/MS/MS) experiment performed on a 'hybrid' tandem mass spectrometer of sector--quadrupole--sector configuration. Tentatively, it is proposed that population of an excited state accounts for the non-ergodic behavior of 1(+*) upon collision with oxygen or nitric oxide. Ab initio molecular orbital calculations using molecular orbital theory (UMP2, UCCSD(T)) and density functional theory (B3LYP) with 6--31G(d,p) and 6--311++G(d,p) basis sets were used to evaluate the relative energy of the excited quartet state of 1(+*) radical cations. This quartet state is calculated to lie about 3.6 eV above the (2)A(") ground state and 0.9 eV above the C(4)H(4)O(+*)+S dissociation products. It is proposed that the quartet ion serves as the precursor for the spontaneous desulfuration.

Siderotic nodules in the cirrhotic liver at MR imaging with explant correlation: no increased frequency of dysplastic nodules and hepatocellular carcinoma

PURPOSE

To determine the sensitivity of magnetic resonance (MR) imaging for detection of siderotic nodules in patients with cirrhosis and whether the frequency of hepatocellular carcinoma (HCC) and dysplastic nodules is greater if siderotic nodules are present.

MATERIALS AND METHODS

MR imaging (1.5 T) was performed within 0-117 days (mean, 30 days) before liver transplantation in 77 patients. Two readers retrospectively evaluated gradient-echo (GRE) (echo time [TE], > or = 9 and 4-5 msec) and turbo short inversion time inversion-recovery or T2-weighted images for low-signal-intensity nodules. Whole-explant pathologic correlation was available in every case.

RESULTS

At explantation, 28 (36%) of 77 patients had HCC, 25 (32%) had dysplastic nodules, and nine (12%) had both; 35 (45%) patients had siderotic nodules. The sensitivity of GRE imaging with 9-msec or longer TE for the detection of siderotic nodules was 80% (28 of 35) but decreased to 31% (11 of 35) with 4-5-msec TE. Frequency of HCC was not significantly higher (P =.27) in patients with (43% [15 of 35]) than in patients without (31% [13 of 42]) siderotic nodules. Frequency of dysplastic nodules also was not significantly higher (P =.42) in patients with (37% [13 of 35]) than in patients without (29% [12 of 42]) siderotic nodules.

CONCLUSION

Sensitivity of MR imaging for the detection of siderotic nodules was improved with use of GRE pulse sequences with longer TEs of 9 msec or greater (80%) versus 4-5 msec (31%); however, there was no significant increased frequency of HCC or dysplastic nodules in patients with pathologically proved siderotic nodules.

Siderotic nodules at MR imaging: regenerative or dysplastic?

OBJECTIVE

To determine if iron containing "siderotic" nodules detected at magnetic resonance (MR) imaging are regenerative (RN) or dysplastic (DN) and to attempt to identify features that may distinguish them.

MATERIAL AND METHODS

MR imaging (1.5 T) was performed on 77 cirrhotic patients who underwent orthotopic liver transplantation within 0-117 days (mean 30 days) of MR imaging. Two readers retrospectively evaluated breath-hold gradient-echo pulse sequences (echo time > or =9.0 ms, flip angle < or =45 degrees) for the presence of hypointense nodules, which were classified as micronodular (< or =3 mm), macronodular (>3 mm), or mixed. Nodule distribution was classified as focal (<5), scattered (5-20), or diffuse (>20) per slice. Thin section pathologic correlation was available in all cases, and Prussian blue iron stains were performed.

RESULTS

Of 35 patients with pathologically proven siderotic nodules, 10 (29%) had at least 2 siderotic DN. MR detected siderotic nodules in 10 of 10 (100%) patients with siderotic DN and RN, and in 18 of 25 patients (72%) with siderotic RN only.

CONCLUSION

Siderotic RN cannot be reliably distinguished from siderotic DN with MR imaging, and therefore the widely used term "siderotic regenerative nodule" should be avoided and replaced by "siderotic nodule."

Dysplastic nodules and hepatocellular carcinoma: sensitivity of digital subtraction hepatic arteriography with whole liver explant correlation

PURPOSE

The purpose of this work was to determine the sensitivity of hepatic digital subtraction arteriography (DSA) for the detection of hepatocellular carcinoma (HCC) and dysplastic nodules (DNs) when compared with pathological findings from whole liver explants.

METHOD

Twenty-one patients 30-72 years old (mean 54 years) with cirrhosis and known or clinically suspected HCC (20 prior to chemoembolization) underwent hepatic DSA with subsequent transplantation within 80 days (mean 32 days). The prospective DSA report was compared with pathologic findings from explanted livers.

RESULTS

Overall, DSA detected 31 of 95 HCC lesions for a sensitivity of 33%. Of these 31 lesions, 28 were hypervascular and 3 were hypovascular. DSA detected all six HCCs measuring >5 cm, all six HCCs measuring 3-5 cm, and all five HCCs 2-3 cm, resulting in a sensitivity of 100% (17/17) for HCC >2 cm. DSA detected 7 of 18 HCCs measuring 1-2 cm (sensitivity 39%) and 7 of 60 HCCs < or =1 cm (sensitivity 12%). Overall sensitivity for DSA in detection of HCC < or =2 cm was 18% (14/78 lesions). None of 17 DNs (0.2-1.5 cm in size) was identified on DSA.

CONCLUSION

DSA is insensitive to small HCC (< or =2 cm), carcinomatosis arising within nodules, and DN.

Inactivating mutation in the human parathyroid hormone receptor type 1 gene in Blomstrand chondrodysplasia

A single homozygous nucleotide exchange in exon E3 of the gene encoding the parathyroid hormone receptor type 1 (PTHR1) was identified in an infant with Blomstrand chondrodysplasia born to consanguineous parents. This alteration changes a strictly conserved proline residue at position 132 in the receptor's amino terminal extracellular domain to leucine. COS-1 cells expressing the mutant receptor did not accumulate cyclic adenosine 3',5'-monophosphate in response to PTH or PTH-related peptide (PTHrP) and did not bind the radiolabeled ligand. Expression of the mutant protein on the cell surface of transiently transfected COS-1 cells and in growth plate chondrocytes derived from the affected infant suggests that proline 132 is critical for the receptor's intrinsic binding activity. These findings suggest that the Blomstrand form of human short-limbed dwarfism arises from defective PTHR1 signaling in the developing cartilaginous skeleton.

Dissociation of IGF2 and H19 imprinting in human brain

The human IGF2 and H19 genes are imprinted in most normal tissues. Alterations of genomic imprinting or loss of imprinting (LOI) have been observed in a number of malignant tumors. Although LOI has been linked to tumorigenesis, loss of IGF2 imprinting has also been observed in choroid plexus and leptomeninges in normal mouse brain. We have therefore analyzed the allelic expression of both IGF2 and H19 in human fetal brain and in different regions of human adult brain. In the brains of fetuses of 6-12 weeks gestation, both IGF2 and H19 were transcribed from both parental alleles. In contrast, strictly monoallelic expression of both IGF2 and H19 was observed in all other fetal tissues, suggesting a tissue-specific LOI in the central nervous system. In adult brain, LOI of IGF2 was region-specific. IGF2 was expressed from both parental alleles in the pons, but not in globus palludus, Raphe nucleus and hypothalamus. H19 expression was drastically reduced in adult brain compared to fetal brain, and was detectable only in the pons and globus palludus. In contrast to IGF2, the expression of H19 in adult pons was monoallelic. Examination of IGF2 promoter usage indicated predominant utilization of promoter P3 in all fetal and adult brain tissues. The LOI of IGF2 therefore reflects biallelic expression from the predominant promoter. IGF2 transcripts derived from the less abundant promoter P1, however, showed monoallelic expression in the adult pons. Our results suggest that IGF2 and H19 undergo ontogenetic changes in allelic expression and that there is dissociation of IGF2 and H19 imprinting in both fetal and adult human brain.

Population programme in Viet Nam: highlights from the 1997 Demographic and Health Survey

"The most recent Demographic and Health Survey of Viet Nam (VN-DHS II) was conducted in 1997 as a nation-wide survey.... This note attempts to give a general overview of some of the initial findings and general highlights of the [survey]...." Sections are included on fertility, contraception, abortion, and infant mortality.

The nucleus: a target site for parathyroid hormone-related peptide (PTHrP) action

It is becoming increasingly apparent that parathyroid hormone-related peptide (PTHrP) modulates cellular function in a dual mode of action: first, by binding and activating its cognate cell surface G-protein-coupled receptor and, second, by direct intracellular effects following translocation to the nucleus and/or nucleolus of the target cell. Little is presently known about the mechanisms and events that determine the timing and degree of PTHrP nuclear translocation or the role it may serve in normal or dysregulated cellular function. Clarifying the nuclear actions of PTHrP would add significantly to our present understanding of this protein as a signaling molecule during embryonic development and as an oncoprotein whose expression in many tumors correlates with increased tumor aggressiveness and propensity for metastasis.

Mutations in microphthalmia, the mouse homolog of the human deafness gene MITF, affect neuroepithelial and neural crest-derived melanocytes differently

The mouse microphthalmia (Mitf) gene encodes a basic-helix-loop-helix-zipper transcription factor whose mutations are associated with abnormalities in neuroepithelial and neural crest-derived melanocytes. In wild type embryos, Mitf expression in neuropithelium and neural crest precedes that of the melanoblast marker Dct, is then co-expressed with Dct, and gradually fades away except in cells in hair follicles. In embryos with severe Mitf mutations, neural crest-derived Mitf-expressing cells are rare, lack Dct expression, and soon become undetectable. In contrast, the neuroepithelial-derived Mitf-expressing cells of the retinal pigment layer are retained, express Dct, but not the melanogenic enzyme genes tyrosinase and Tyrp1, and remain unpigmented. The results show that melanocyte development critically depends on functional Mitf and that Mitf mutations affect the neural crest and the neuroepithelium in different ways.

Effect of cow milk on pulmonary function in atopic asthmatic patients

BACKGROUND

There is a perception by some asthmatic patients that stimulation of respiratory mucous production by cow milk may worsen airway obstruction.

OBJECTIVE

To determine whether cow milk ingestion reduces bronchial airflow in asthmatic patients as measured by standard spirometry.

METHODS

Twenty-five atopic adults with mild asthma but no history of cow milk allergy or lactose intolerance participated in a prospective, randomized, double-blind, placebo-controlled crossover study. Subjects were randomly assigned to ingest either a solution containing cow milk powder or a placebo solution, received neither during a 14-day washout period, then ingested the alternate solution. Forced vital capacity (FVC), forced expiratory volume in 1 second (s) (FEV1), and FEV1/FVC were measured at 30 minutes, 1 hour (h), and 7 hours after challenge. A > or = 20% decrease in FEV1 or FEV1/FVC was considered clinically significant.

RESULTS

FEV1 was slightly lower at 30 minutes than the baseline value (mean change, .6% to 3.3%) for both challenges. None of the subjects experienced any adverse symptoms, acute or delayed, after cow milk or placebo challenges. Statistically significant changes in FEV1 were reached 30 minutes after cow milk challenge (P = .0007) and at one hour after placebo (P = .0027). These changes are not clinically significant.

CONCLUSION

Although this study disclosed no acute or delayed asthmatic symptoms or deterioration of pulmonary function detected by using conventional spirometry, methacholine inhalation before and after cow milk challenge may be more sensitive for evaluation of cow milk-induced bronchial hyperreactivity.

Melanocyte development in vivo and in neural crest cell cultures: crucial dependence on the Mitf basic-helix-loop-helix-zipper transcription factor

The more than 20 different Mitf mutations in the mouse are all associated with deficiencies in neural crest-derived melanocytes that range from minor functional disturbances with some alleles to complete absence of mature melanocytes with others. In the trunk region of wild-type embryos, Mitf-expressing cells that coexpressed the melanoblast marker Dct and the tyrosine kinase receptor Kit were found in the dorsolateral neural crest migration pathway. In contrast, in embryos homozygous for an Mitf allele encoding a non-functional Mitf protein, Mitf-expressing cells were extremely rare, no Dct expression was ever found, and the number of Kit-expressing cells was much reduced. Wild-type neural crest cell cultures rapidly gave rise to cells that expressed Mitf and coexpressed Kit and Dct. With time in culture, Kit expression was increased, and pigmented, dendritic cells developed. Addition of the Kit ligand Mgf or endothelin 3 or a combination of these factors all rapidly increased the number of Dct-positive cells. Cultures from Mitf mutant embryos initially displayed Mitf-positive cells similar in numbers and Kit-expression as did wild-type cultures. However, Kit expression did not increase with time in culture and the mutant cells never responded to Mgf or endothelin 3, did not express Dct, and never showed pigment. In fact, even Mitf expression was rapidly lost. The results suggest that Mitf first plays a role in promoting the transition of precursor cells to melanoblasts and subsequently, by influencing Kit expression, melanoblast survival.

A Schwann cell matrix component of neuromuscular junctions and peripheral nerves

Molecules localized to the synapse are potential contributors to processes unique to this specialized region, such as synapse formation and maintenance and synaptic transmission. We used an immunohistochemical strategy to uncover such molecules by generating antibodies that selectively stain synaptic regions and then using the antibodies to analyse their antigens. In this study, we utilized a monoclonal antibody, mAb 6D7, to identify and characterize an antigen concentrated at frog neuromuscular junctions and in peripheral nerves. In adult muscle, immunoelectron microscopy indicates that the antigen is located in the extracellular matrix around perisynaptic Schwann cell at the neuromuscular junction and in association with myelinated and nonmyelinated axons in peripheral nerves. The maintenance of the mAb 6D7 epitope is innervation-dependent but is muscle-independent; it disappears from the synaptic region within 2 weeks after denervation, but persists after muscle damage when the nerve is left intact. mAb 6D7 immunolabelling is also detected at the neuromuscular junction in developing tadpoles. Biochemical analyses of nerve extracts indicate that mAb 6D7 recognizes a glycoprotein of 127 kDa with both N- and O-linked carbohydrate moieties. Taken together, the results suggest that the antigen recognized by mAb 6D7 may be a novel component of the synaptic extracellular matrix overlying the terminal Schwann cell. The innervation-sensitivity of the epitope at the neuromuscular junction suggests a function in the interactions between nerves and Schwann cells.

Variations in Vietnamese marriages, births and infant deaths by months of the Julian calendar and years of the Vietnamese and Chinese astrological calendars

The timing of births and marriages in Vietnam appears to have some statistically significant relationships with the signs of the Chinese and Vietnamese astrological calendars. Years considered to be good years have significantly more births and marriages than years that are not considered as desirable. Births and marriages also have some significant variations with seasons of the year. Infant deaths do not appear to have any significant relationships with the astrological signs although infant mortality has some significant relationships with seasons of the year. The findings indicate that there is some purposeful planning for marriages and births to coincide with optimal times defined in the astrological calendars.