A new oral model of free fatty acid kinetics to assess lipolysis in subjects with and without type 2 diabetes

Assessing free fatty acids (FFAs) kinetics and the role of insulin and glucose on FFA lipolysis and disposal may improve our understanding of the pathogenesis of type 2 diabetes (T2D). Some models have been proposed to describe FFA kinetics during an intravenous glucose tolerance test and only one during an oral glucose tolerance test. Here, we propose a model of FFA kinetics during a meal tolerance test and use it to assess possible differences in postprandial lipolysis in individuals with type 2 diabetes (T2D) and individuals with obesity without type 2 diabetes (ND). We studied 18 obese ND and 16 T2D undergoing three meal tolerance tests (MTT) on three occasions (breakfast, lunch, and dinner). We used plasma glucose, insulin, and FFA concentrations collected at breakfast to test a battery of models and selected the best one based on physiological plausibility, ability to fit the data, precision of parameter estimates, and the Akaike parsimony criterion. The best model assumes that the postprandial suppression of FFA lipolysis is proportional to the above basal insulin, while FFA disposal is proportional to FFA concentration. It was used to compare FFA kinetics in ND and T2D along the day. The maximum lipolysis suppression occurred significantly earlier in ND than T2D (39 ± 6 min vs. 102 ± 13 min, 36 ± 4 min vs. 78 ± 11 min, and 38 ± 6 min vs. 84 ± 13 min, P < 0.01, at breakfast, lunch, and dinner, respectively), making lipolysis significantly lower in ND than T2D. This is mainly attributable to the lower insulin concentration in the second group. This novel FFA model allows to assess lipolysis and insulin antilipolytic effect in postprandial conditions.NEW & NOTEWORTHY In this study, we propose a new mathematical model able to quantify postprandial FFA kinetics and adipose tissue insulin sensitivity in both subjects with obesity without type 2 diabetes (ND) and subjects with type 2 diabetes (T2D). Results show that the slower postprandial suppression of lipolysis in T2D contributes to the higher free fatty acid (FFA) concentration that, in turn, may contribute to hyperglycemia.

Design of multi neutron-to-gamma converter array for measuring time resolved ion temperature of inertial confinement fusion implosions

The ion temperature varying during inertial confinement fusion implosions changes the amount of Doppler broadening of the fusion products, creating subtle changes in the fusion neutron pulse as it moves away from the implosion. A diagnostic design to try to measure these subtle effects is introduced-leveraging the fast time resolution of gas Cherenkov detectors along with a multi-puck array that converts a small amount of the neutron pulse into gamma-rays, one can measure multiple snapshots of the neutron pulse at intermediate distances. Precise measurements of the propagating neutron pulse, specifically the variation in the peak location and the skew, could be used to infer time-evolved ion temperature evolved during peak compression.

Role of angiotensin peptides in risk stratification and prognostication for heart failure: focus on plasma Ang 1–7/Ang II ratio

Background

ACE2 and Ang 1–7 are endogenous negative regulators of the renin-angiotensin system (RAS) exerting cardioprotective effects in models of heart failure (HF). Recombinant ACE2 markedly increased plasma Ang 1–7 and lowered Ang II levels in clinical trials. Elevated plasma ACE2 activity is associated with adverse outcomes in HF patients. However, the direct effects of systemic and tissue ACE2 activation on angiotensin peptides in relation to long-term HF outcomes has yet to be examined.

Purpose

To generate insights into the ACE2 mediated cardioprotective arm through the relative levels of its substrates and products using the plasma Ang 1–7/Ang II ratio, and assess its prognostic utility in HF patients.

Methods

110 HF patients were prospectively enrolled from outpatient clinics and the emergency department. Comprehensive circulating and equilibrium levels of plasma angiotensin peptides were assessed using novel liquid chromatography-mass spectrometry/mass spectroscopy techniques. Plasma aldosterone, BNP, active renin activity and clinical profiles were captured at baseline. Patients were stratified into above and below median cohorts based on equilibrium and circulating levels of Ang 1–7/Ang II ratio, as a surrogate for ACE2 functionality. During a median follow-up of 5.1±0.8 years, composite clinical outcomes were assessed through all-cause in-patient hospitalizations and mortality.

Results

Circulating and equilibrium angiotensin peptide levels strongly correlated in our patient cohort. All-cause mortality for HF patients with equilibrium Ang 1–7/Ang II ratios above the median showed higher survival rates compared to below median patients (76.4% vs. 50.9%; p=0.004); similar results were observed for circulating Ang 1–7/Ang II ratios (72.7% vs. 54.5%; p=0.041). Adjusting for covariates, elevated equilibrium (HR: 0.24; 95% CI: 0.09 to 0.69; p=0.008) and circulating (HR: 0.35; 95% CI: 0.13 to 0.94; p=0.036) Ang 1–7/Ang II ratios was associated with improved survival. Lower hospitalization duration was also associated with elevated equilibrium (p&lt;0.001) and circulating (p=0.023) Ang 1–7/Ang II ratios. In nested models, net reclassification analysis showed considerable improvement in risk prediction for all-cause mortality at 5 years provided by both the equilibrium (+45.0% [95% CI: 7.3% to 82.7%]) and circulating Ang 1–7/Ang II ratios (+24.3% [95% CI: 0.4% to 59.6%]) respectively.

Conclusions

We extensively profiled plasma angiotensin peptides in HF patients and identified elevated ACE2 signature, reflected through the Ang 1–7/Ang II ratio, as an independent and incremental predictor of beneficial outcomes, higher survival rate, and decreased hospitalization duration. These findings provide important clinical evidence supporting strategies aiming to promote the beneficial ACE2/Ang 1–7/Mas receptor axis concurrent with RAS blockade therapies inhibiting the detrimental ACE/Ang II/AT1 receptor axis.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Alberta Innovates, Canadian Institute of Health Research

An ensemble model for forecasting infectious diseases in India

Time series modelling and forecasting plays an important role in various domains. The objective of this paper is to construct a simple average ensemble method to forecast the number of cases for infectious diseases like dengue and typhoid and compare it by applying models for forecasting. In this paper we have also evaluated the correlation between the number of typhoid and dengue cases with the ecological variables. The monthly data of dengue and typhoid cases from 2014 to 2017 were taken from integrated diseases surveillance programme, Government of India. This data was analysed by three models namely support vector regression, neural network and linear regression. The proposed simple average ensemble model was constructed by ensemble of three applied regression models i.e. SVR, NN and LR. We combine the regression models based upon the error metrics such as Mean Square Error, Root Mean Square Error and Mean Absolute Error. It was found that proposed ensemble method performed better in terms of forecast measures. The finding demonstrates that the proposed model outperforms as compared to already available applied models on the basis of forecast accuracy.

Intrinsic properties of medical devices: considerations for economic evaluation

Introduction: In recent decades, medical devices (MDs) have increasingly become an integral part of patient care. However, when it comes to designing and appraising economic models, researchers typically follow pharmaceutical templates (e.g. CHEERS) to assess their economic viability. This study evaluates the generalizability of four device-specific criteria, as recommended by the recent MedtechHTA project, of learning curve, incremental innovation, dynamic pricing, and organizational impact with a broader group of MDs including diagnostics and implantables. The purpose was to determine the applicability of these criteria to a broader range of MDs.Areas Covered: We determined the extent to which these criteria could be applied to each device type and attempted to identify common themes. We performed a literature search using PubMed and Google of a range of devices to understand the clinical significance, operation, and economic viability.Expert Opinion: Our findings suggest that the four characteristics are not applicable to all device types. Prior evaluation of a device's intrinsic properties (such as longevity and device location) and its FDA risk classification could help to indicate the applicability of the criteria. Documenting this process when assessing the additional four criteria on the CHEERS checklist would improve the transparency of future economic evaluations.

Better healthcare setting for better healthcare service quality

Purpose

The purpose of this paper is to assess and compare different private healthcare settings based on perceived service quality in Indian context using analytical hierarchy process (AHP). The Indian private healthcare sector has been controlled by three categories of healthcare settings, namely, nursing clinics (NCs), non-corporate hospitals (NCHs) and corporate hospitals (CHs).

Design/methodology/approach

AHP was used to rank order of healthcare setting regarding the service quality dimensions and relative standings of every service provider with respect to its competitors. The authors collected random data from nine private hospitals situated in eastern and southern India. The authors proposed a feasible appraising approach based on AHP to decide the sustainability priority of dimensions like reliability, physical environment, empathy, efficiency, timeliness, transparency, affordability, communication, appropriateness and consistency in the Indian private healthcare industry.

Findings

The result demonstrates that Indian NCHs are performing better on customers’ perceived service quality, followed by CHs and NCs. The comparative performance of healthcare settings is an attempt to establish a performance ranking.

Originality/value

This research assesses dimensions of the service quality that need urgent attention. The results may provide insight to healthcare managers as to how they can improve their service quality in order to match customer expectation and to improve business performance.

Phenolic compound-mediated single-step fabrication of copper oxide nanoparticles for elucidating their influence on anti-bacterial and catalytic activity

A single-step synthesis of copper oxide nanoparticles (CuO NPs) from a phenolic compound (rosmarinic acid) at ambient temperature was developed in this study.

A rare variation of cutaneous innervation of dorsum of hand by posterior interosseous nerve

Anatomical knowledge of variation of cutaneous supply of hand is required to the anesthetist to give local anesthesia and to the surgeon for various operations around wrist. The present case was reportedto enlighten the knowledge of anatomists as well as to the clinicians. During routine dissection of 70 year old male cadaver a rare variation of distribution of posterior interosseous nerve on dorsum of hand of right side was observed. The adjacent sides of index and middle fingers supplied by posterior interosseous nerve. Cutaneous nerve supply of thumb and lateral side of index finger was by three proper digital branches from superficial division of radial nerve and rest was supplied by ulnar nerve. Anatomical knowledge of this variation willbe useful to anaesthetists and surgeons during various operations.

Supernumerary muscle of tarsal tunnel: a case report

Supernumerary muscles are an infrequent fmding during dissections around the ankle. This report focusses on the finding of one such muscle which was found in the tarsal tunnel of the left lower limb unilaterally during routine dissection of a 70 year old male cadaver in Bankura Sammilani Medical College, West Bengal.This supernumerary muscle had a single head of origin from the flexor hallucis longus and posterior intermuscular septum and was traced to its insertion into the flexor digitorum accessorius in the sole and hence was named flexor digitorum accessorius longus, and its relations with the neurovascular bundle were noted. Flexor digitorum accessorius longus may be a cause of tarsal tunnel syndrome so it should be kept in mind during its management. It may also produce symptoms mimicking soft tissue tumors. Thus knowledge of this muscle will be of utmost importance to anatomists, clinicians, radiologists and athletes.

Riboflavin conjugated temperature variant ZnO nanoparticles with potential medicinal application in jaundice

Significant ameliorative efficiency of riboflavin conjugated ZnO nanoparticles against jaundice stress at molecular and cellular levels.

Green synthesis of zinc oxide nanoparticles using Hibiscus subdariffa leaf extract: effect of temperature on synthesis, anti-bacterial activity and anti-diabetic activity

Particle size dependent anti-bacterial and anti-diabetic activities of green synthesized ZnO nanoparticles.

Assessment of insulin action on carbohydrate metabolism: physiological and non-physiological methods

Carbohydrate metabolism in humans is regulated by insulin secretion from pancreatic β-cells and glucose disposal by insulin-sensitive tissues. Insulin facilitates glucose utilization in peripheral tissues and suppresses hepatic glucose production. Any defects in insulin action predispose an individual to glucose intolerance and Type 2 diabetes mellitus. Early detection of defects in insulin action could provide opportunities to prevent or delay progression of the disease state. There are different approaches to assess insulin action. Initial methods, such as peripheral insulin concentration and simple indices, have several limitations. Subsequently, researchers developed methodologies using intravenous glucose infusion to determine glucose fluxes. However, these methodologies are limited by being non-physiological. Newer, innovative techniques that have been developed are more sophisticated and physiological. By modelling glucose kinetics using isotope dilution techniques, several robust parameters can be obtained that are physiologically relevant and sound. This brief review summarizes most of the non-physiological and physiological methodologies used to measure the variables of insulin action.

Effects of 11β-hydroxysteroid dehydrogenase-1 inhibition on hepatic glycogenolysis and gluconeogenesis

The aim of this study was to determine the effect of prolonged 11β-hydroxysteroid dehydrogenase-1 (11β-HSD1) inhibition on basal and hormone-stimulated glucose metabolism in fasted conscious dogs. For 7 days prior to study, either an 11β-HSD1 inhibitor (HSD1-I; n = 6) or placebo (PBO; n = 6) was administered. After the basal period, a 4-h metabolic challenge followed, where glucagon (3×-basal), epinephrine (5×-basal), and insulin (2×-basal) concentrations were increased. Hepatic glucose fluxes did not differ between groups during the basal period. In response to the metabolic challenge, hepatic glucose production was stimulated in PBO, resulting in hyperglycemia such that exogenous glucose was required in HSD-I (P < 0.05) to match the glycemia between groups. Net hepatic glucose output and endogenous glucose production were decreased by 11β-HSD1 inhibition (P < 0.05) due to a reduction in net hepatic glycogenolysis (P < 0.05), with no effect on gluconeogenic flux compared with PBO. In addition, glucose utilization (P < 0.05) and the suppression of lipolysis were increased (P < 0.05) in HSD-I compared with PBO. These data suggest that inhibition of 11β-HSD1 may be of therapeutic value in the treatment of diseases characterized by insulin resistance and excessive hepatic glucose production.

Elevated NEFA levels impair glucose effectiveness by increasing net hepatic glycogenolysis

AIMS/HYPOTHESIS

Acute hyperglycaemia rapidly suppresses endogenous glucose production (EGP) in non-diabetic individuals, mainly by inhibiting glycogenolysis. Loss of this 'glucose effectiveness' contributes to fasting hyperglycaemia in type 2 diabetes. Elevated NEFA levels characteristic of type 2 diabetes impair glucose effectiveness, although the mechanism is not fully understood. Therefore we examined the impact of increasing NEFA levels on the ability of hyperglycaemia to regulate pathways of EGP.

METHODS

We performed 4 h 'pancreatic clamp' studies (somatostatin; basal glucagon/growth hormone/insulin) in seven non-diabetic individuals. Glucose fluxes (D-[6,6-(2)H(2)]glucose) and hepatic glycogen concentrations ((13)C magnetic resonance spectroscopy) were quantified under three conditions: euglycaemia, hyperglycaemia and hyperglycaemia with elevated NEFA (HY-NEFA).

RESULTS

EGP was suppressed by hyperglycaemia, but not by HY-NEFA. Hepatic glycogen concentration decreased ~14% with prolonged fasting during euglycaemia and increased by ~12% with hyperglycaemia. In contrast, raising NEFA levels in HY-NEFA caused a substantial ~23% reduction in hepatic glycogen concentration. Moreover, rates of gluconeogenesis were decreased with hyperglycaemia, but increased with HY-NEFA.

CONCLUSIONS/INTERPRETATION

Increased NEFA appear to profoundly blunt the ability of hyperglycaemia to inhibit net glycogenolysis under basal hormonal conditions.

Fee comparisons of treatments for nonmelanoma skin cancer in a private practice academic setting

OBJECTIVE

To compare fees for biopsy, treatment procedure, repair, and 2-month follow-up for nonmelanoma skin cancer (NMSC) treatments: electrodesiccation and curettage (ED&C), excision, and Mohs micrographic surgery (MMS).

METHODS

A cost comparison of 936 primary NMSCs diagnosed in 1999/2000 at a University affiliated dermatology practice. Clinical data was from medical record review. 2007 Medicare Fee Schedule costs determined fees for surgical care. Pearson chi-square tests, t-tests and analysis of variance compared fee differences. Linear regression determined independent effects of tumor and treatment characteristics on fees.

RESULTS

Mean fees/lesion were $463 for ED&C, $1,222 for excision, and $2,085 for MMS (p < .001). For all treatments, primary procedure costs were highest (38%, 45%, and 41%). Total repair fees were higher with MMS ($735) vs excisions ($197). Fees were higher for head and neck tumors (p < .001), H-zone tumors (p < .001), and tumors smaller than 10 mm in diameter (p = .04). Regression models predicted that the treatment fees would be $2,109 for MMS and $1,252 for excision (p < .001). Tumor size greater than 10 mm in diameter (added $128), tumors on the head and neck (added $966), and MMS (added $857 vs excision) were independently related to higher fees (p < .001).

CONCLUSION

Even after adjusting for risk factors, MMS has higher fees than excision for primary NMSC. Repairs accounted for the majority of this difference. These fee comparisons provide a basis for comparative effectiveness studies of treatments for this common cancer.

The effect of prophylaxis on pediatric HIV costs

The objective of this study was to determine and compare the cost to treat HIV(+) and HIV(-) pediatric patients both before and after HIV prophylaxis became the standard of care. Retrospective chart review of a pediatric HIV/AIDS specialty clinic's medical charts was conducted for clinical and healthcare utilization data on 125 children diagnosed from 1986 to 2007. Mean HIV-related costs were compared using bootstrapped t-tests for children born in the pre-prophylaxis (1979-1993) and prophylaxis eras (1994-2007). Patients were also stratified into two categories based on death during the follow-up period. Lastly, national cost-savings were estimated using mean costs, national number of at-risk births, and national perinatal HIV transmission rates in each era. For HIV(+) children, mean annual per patient treatment cost was $15,067 (95% CI: $10,169-$19,965) in the pre-prophylaxis era (n = 40) and $14,959 (95% CI: $9140-$20,779) in the prophylaxis era (n = 14); difference not statistically significant (p > 0.05). For HIV(-) children, mean annual per patient treatment cost was $204 (95% CI: $219-$627) for the pre-prophylaxis era (n = 2) and $427 (95% CI: $277-$579) for the prophylaxis era (n = 69); difference statistically significant (p < 0.05). A projected cost-savings of $16-23 million annually in the USA was observed due to the adoption of prophylaxis treatment guidelines in pediatric HIV care. The prophylaxis era of pediatric HIV treatment has been successful in decreasing perinatal HIV transmission and mortality, as reflected by clinical trials and national cost-savings data, and emphasizes the value of the rapid adoption of evidence-based practice guidelines.

Pediatric HIV costs across three treatment eras from 1986 to 2007

OBJECTIVE

Life has changed dramatically for infants exposed perinatally to HIV to HIV primarily because of a successful translational research program that has also affected treatment costs. We compared treatment costs among HIV+ patients in an HIV/AIDS specialty clinic across 3 treatment eras: monotherapy (pre-1990), combination therapy (1990-1996), and highly active antiretroviral therapy (HAART) (1997-2007). We also estimated cumulative health care costs among pediatric HIV/AIDS patients born in each era.

PATIENTS AND METHODS

Data on health care use were collected from medical records of 126 infants born to HIV+ mothers during a 21-year period (1986-2007) (728 person-years). The Drug Topics Red Book 1999 was used for drug costs, the Current Procedural Terminology Medicare Fee Schedule codes for outpatient costs, and the Healthcare Cost and Utilization Project Kids' Inpatient Database for inpatient costs. Generalized estimating equations and bootstrapped ordinary least-squares models were used to determine 2007 costs, cumulative costs, and cost savings.

RESULTS

Lifetime cost savings with HAART were $6.7 to $23.3 million, depending on incidence. Average total costs per HIV+ person per month were $1306 ($318 for drugs, $896 for total medical) in the monotherapy era, $2289 ($891 for drugs, $1180 for total medical) in the combination-therapy era, and $1814 ($1241 for drugs, $320 for total medical) in the HAART era. Total costs during the HAART era were 25.2% lower than costs during the combination-therapy era, because the 34% higher HAART drug costs were compensated for by total medical costs (inpatient+outpatient) that were 57% lower, which was a significant change (P<.001). The cumulative costs for treatment of an HIV+ patient were highest during the monotherapy era ($196,860) and lowest during the HAART era ($181,436).

CONCLUSIONS

Our results show that the cost burden for the treatment of HIV+ pediatric patients has decreased over time. This historical examination of treatment-era costs demonstrates the value of technologic advances in treatment.

Minimal model assessment of hepatic insulin extraction during an oral test from standard insulin kinetic parameters

In this article, a first aim was to develop a minimal modeling approach to noninvasively assess hepatic insulin extraction in 204 healthy subjects studied with a standard meal by coupling the already available meal C-peptide minimal model with a new insulin model. The ingredients of this model are posthepatic IDR, which in turn is described in terms of pancreatic ISR and hepatic insulin extraction HE, and a linear monocompartmental model of insulin kinetics. Even if ISR is provided by the C-peptide minimal model, the simultaneous assessment of HE and insulin kinetics is critical, since compensations may arise between parameters describing these two processes. Therefore, as a second aim of this study, a method was developed to predict standard values of insulin kinetic parameters in an individual on the basis of the individual's anthropometric characteristics. The statistical analysis, based on linear regression of insulin kinetic parameters estimated from IM-IVGTT data performed on the same subjects, demonstrated that insulin kinetic parameters can be accurately predicted from age and body surface area. Once kinetic parameters of the new insulin model were fixed to these values, HE profile and indexes during a meal were reliably estimated in each individual, indicating a significant suppression during the meal since the overall index of HE, equal to 60 +/- 1% in the basal state, is reduced to 40 +/- 1% during a meal. However, standard parameters provide an approximation of the individual one; thus, the third aim was to define the impact on estimated indexes of using standard instead of individually estimated values. Our results showed that the 25% uncertainty affecting as an average insulin kinetic parameters of an individual, when they are predicted from age and body surface area, translates into a similar relative uncertainty in the individual's hepatic insulin extraction indexes.

Sociodemographic disparities in epilepsy care: Results from the Houston/New York City health care use and outcomes study

PURPOSE

The purpose of this study was to identify sociodemographic disparities in health care use among epilepsy patients receiving care at different sites and the extent to which the disparities persisted after adjusting for patient characteristics and site of care.

METHODS

Three months of health care use data were obtained from baseline interviews of approximately 560 patients at four sites. One-half of the patients were from a Houston site and two NYC sites that serve predominantly low-income, minority, publicly insured, or uninsured patients. The other half were at the remaining site in Houston that serves a more balanced racial/ethnic and higher sociodemographic population. Differences in general and specialist visits, hospital emergency room (ER) care, and hospitalizations were associated with race/ethnicity, income, and coverage. Logistic regression was used to assess the extent to which the differences persisted when adjusting for individual patient characteristics and site of care.

RESULTS

Compared to whites, blacks and Hispanics had higher rates of generalist visits [odds ratio (OR) = 5.3 and 4.9, p < 0.05), ER care (OR = 3.1 and 2.9, p < 0.05) and hospitalizations (OR = 5.4 and 6.2, p < 0.05), and lower rates of specialist visits (OR = 0.3 and 0.4, p < 0.05). A similar pattern was found related to patient income and coverage. The magnitude and significance of the disparities persisted when adjusting for individual characteristics but decreased substantially or were eliminated when site of care was added to the model.

DISCUSSION

There are sociodemographic disparities in health care for people with epilepsy that are largely explained by differences in where patients receive care.

Effects of pioglitazone and metformin on NEFA-induced insulin resistance in type 2 diabetes

AIMS/HYPOTHESIS

We sought to determine whether pioglitazone and metformin alter NEFA-induced insulin resistance in type 2 diabetes and, if so, the mechanism whereby this is effected.

METHODS

Euglycaemic-hyperinsulinaemic clamps (glucose approximately 5.3 mmol/l, insulin approximately 200 pmol/l) were performed in the presence of Intralipid-heparin (IL/H) or glycerol before and after 4 months of treatment with pioglitazone (n = 11) or metformin (n = 9) in diabetic participants. Hormone secretion was inhibited with somatostatin in all participants.

RESULTS

Pioglitazone increased insulin-stimulated glucose disappearance (p < 0.01) and increased insulin-induced suppression of glucose production (p < 0.01), gluconeogenesis (p < 0.05) and glycogenolysis (p < 0.05) during IL/H. However, glucose disappearance remained lower (p < 0.05) whereas glucose production (p < 0.01), gluconeogenesis (p < 0.05) and glycogenolysis (p < 0.05) were higher on the IL/H study day than on the glycerol study day, indicating persistence of NEFA-induced insulin resistance. Metformin increased (p < 0.001) glucose disappearance during IL/H to rates present during glycerol treatment, indicating protection against NEFA-induced insulin resistance in extrahepatic tissues. However, glucose production and gluconeogenesis (but not glycogenolysis) were higher (p < 0.01) during IL/H than during glycerol treatment with metformin, indicating persistence of NEFA-induced hepatic insulin resistance.

CONCLUSIONS/INTERPRETATION

We conclude that pioglitazone improves both the hepatic and the extrahepatic action of insulin but does not prevent NEFA-induced insulin resistance. In contrast, whereas metformin prevents NEFA-induced extrahepatic insulin resistance, it does not protect against NEFA-induced hepatic insulin resistance.

Virulence attenuation of a UDP-galactose/N-acetylglucosamine beta1,4 galactosyltransferase expressing Leishmania donovani promastigote

Protozoan parasites of the genus Leishmania are the causative agent of leishmaniasis, a disease whose manifestations in humans range from mild cutaneous lesions to fatal visceral infections. Human visceral leishmaniasis is caused by Leishmania donovani. Long-term culture in vitro leads to the attenuation of the parasite. This loss of parasite virulence is associated with the expression of a developmentally regulated UDP-Galactose/N-acetylglucosamine beta 1-4 galactosyltransferase and galactose terminal glycoconjugates as determined by their agglutination with the pea nut agglutinin (PNA). Thus, all promastigotes passaged for more than 11 times were 100% agglutinated with PNA, and represent a homogeneous population of avirulent parasites. Identical concentrations of PNA failed to agglutinate promastigotes passaged for < or =5 times. These PNA(-) promastigotes were virulent. Promastigotes passaged from 5 to 10 times showed a mixed population. The identity of populations defined by virulence and PNA agglutination was confirmed by isolating PNA(+) avirulent and PNA(-) virulent clones from the 7th passage promastigotes. Only the PNA(+) clones triggered macrophage microbicidal activity. The PNA(+) clones lacked lipophosphoglycan. Intravenous administration of [(14)C] galactose-labeled parasite in BALB/c mice resulted in rapid clearance of the parasite from blood with a concomitant accumulation in the liver. By enzymatic assay and RT-PCR we have shown the association of a UDP-Galactose/N-acetylglucosamine beta1,4 galactosyltransferase with only the attenuated clones. By immunofluorescence we demonstrated that the enzyme is located in the Golgi apparatus. By western blot analysis and SDS-PAGE of the affinity-purified protein, we have been able to identify a 29 KDa galactose terminal protein from the avirulent clones.

Modestly increased beta cell apoptosis but no increased beta cell replication in recent-onset type 1 diabetic patients who died of diabetic ketoacidosis

AIMS/HYPOTHESIS

Type 1 diabetes is characterised by a deficit in beta cell mass thought to be due to immune-mediated increased beta cell apoptosis. Beta cell turnover has not been examined in the context of new-onset type 1 diabetes with diabetic ketoacidosis.

METHODS

Samples of pancreas were obtained at autopsy from nine patients, aged 12 to 38 years (mean 24.3+/-3.4 years), who had had type 1 diabetes for less than 3 years before death due to diabetic ketoacidosis. Samples of pancreas obtained at autopsy from nine non-diabetic cases aged 11.5 to 38 years (mean 24.2+/-3.4 years) were used as control. Fractional beta cell area (insulin staining), beta cell replication (insulin and Ki67 staining) and beta cell apoptosis (insulin and TUNEL staining) were measured.

RESULTS

In pancreas obtained at autopsy from recent-onset type 1 diabetes patients who had died of diabetic ketoacidosis, the beta cell deficit varied from 70 to 99% (mean 90%). The pattern of beta cell loss was lobular, with almost all beta cells absent in most pancreatic lobules; islets in lobules not devoid of beta cells had reduced or a near-normal complement of beta cells. Beta cell apoptosis was increased in recent-onset type 1 diabetes, but to a surprisingly modest degree given the marked hyperglycaemia (30 mmol/l), acidosis and presumably high NEFA. Beta cell replication, scattered pancreatic beta cells and beta cells in exocrine ducts were not increased in recent-onset type 1 diabetes.

CONCLUSIONS/INTERPRETATION

These findings do not support the notion of active beta cell regeneration by replication in new-onset type 1 diabetes under conditions of diabetic ketoacidosis. The gluco-lipotoxicity reported in isolated human islets may be less evident in vivo.