A census of general surgery consultants in England and Wales: implications for the current and future surgical workforce

INTRODUCTION

This study aimed to describe the composition of the current general surgical consultant body in England and Wales and quantify levels of inequality within it as well as describe future workforce challenges.

METHODS

This is an observational study of all general surgical departments in England and Wales. Consultant general surgeons were identified and data regarding their gender, country of undergraduate medical education, subspecialty and private practice were recorded.

RESULTS

Of the 2,682 consultant general surgeons in England and Wales identified for this study, just 17% are women, with gender inequality most marked in university teaching hospitals and among certain subspecialties. Almost 40% of consultants did not obtain their primary undergraduate degree in the United Kingdom and there are considerably fewer surgeons who studied abroad in university teaching hospitals. Over 40% of current general surgical consultants have been qualified for more than three decades and there is no equivalent sized group of younger consultants.

CONCLUSIONS

There remains considerable gender and racial inequality in the consultant general surgical workforce, with pockets of a lack of diversity within university or teaching hospital surgical departments and some subspecialties. The proportion of surgeons in their fourth decade of clinical practice represents the largest group of current practising consultants, which points towards an impending workforce crisis should senior clinicians seek to reduce activity or consider taking early retirement.

Profile of neonatal candidiasis in tertiary neonatal intensive care unit: A report from a developing country

BACKGROUND

Systemic candidiasis is an important nosocomial infection in neonatal intensive care units. The objective of this study was to identify the change in the profile of neonatal candidiasis in a tertiary neonatal intensive care unit (NICU) in eastern India in recent times.

METHODS

It was a retrospective review of case records from 2014 to 2019 from a tertiary NICU of eastern India. Data of the fungal sepsis, demographic details, risk factors of fungal sepsis and mortality were collected from 103 neonates.

RESULTS

One hundred and three neonates had blood culture positive for fungal species of which 91 (88.3%) infants weighed ≥1500 g and 66 (64%) infants were term. There was significant higher incidence of candidiasis among outborn (Relative risk of outborn 18.84, 95% CI 10.74-33.05). Prolonged antibiotic usage (>14 days), meropenem usage (>5 days), central catheterization (>5 days), invasive mechanical ventilation (>5 days), surgical intervention were found in 64 (62.1%), 46 (44.6%), 31(30.0%), 40 (38.8%) and 39 (37.8%) infants. Non albicans candida (NAC) was isolated as the predominant species (82/103, 79.6%). Resistance to both of fluconazole and amphotericin B were found in 19 (18.4%) babies. Presence of NAC infection and resistance to both amphotericin B and fluconazole were independent predictors of candida associated mortality in NICU.

CONCLUSION

Neonatal candidiasis is found among outborn infants with higher birth weight and gestational age. NAC species are predominant organisms with resistance to common antifungal drugs.

Clinical and echocardiographic characteristics associated with evolution of patent ductus arteriosus in preterm neonates: A prospective cohort study

BACKGROUND

In preterm infants, persistence of ductus arteriosus is an important medical condition. Functional echocardiography for patent ductus arteriosus (PDA) may guide clinical decision-making regarding treatment requirement strategies. Objectives of the study were to assess the trends of clinical and functional echocardiographic parameters with evolution of ductus arteriosus in babies≤1250 gm of birth weight and to evaluate whether there is any association of these parameters with persistence of ductus.

METHODS

In this prospective observational study, recruited babies were assessed serially for clinical events and functional echocardiography. Babies were classified into three groups: without PDA, with PDA but PDA spontaneously closed (within 7 days) and persistent PDA.

RESULT

We included 143 infants (Birth weight 1017±179 g, gestational age 30.8±2.7 weeks). Out of 60 babies with PDA, PDA failed to close spontaneously in first week in 32 (53.4 %) infants. PDA Doppler flow pattern on day 3 was found to be one of the most significant markers for future ductus. The highest frequency of growing pattern (37.5%) and pulsatile pattern (59.4%) was seen in persistence ductus group. PDA diameter and LA/Ao ratio were found strongly correlated with all other variables except E/A ratio.

CONCLUSION

We noticed persistence of ductus in preterm infants had significant clinical and echocardiographic association. PDA doppler flow pattern on day 3 was found to be a significant marker for future behaviour of ductus. Significant correlation was found among individual functional echocardiographic parameters in babies with PDA. This would guide judicious treatment of PDA in preterm neonates.

Salt Intake Behaviors among Type 2 Diabetic Patients of a Tertiary Level Hospital in Dhaka City

Hypertension and diabetes co-exist frequently. Therefore, salt intake behavior, a risk factor of hypertension, in diabetic patients plays an important role in determining their cardiovascular outcome. The purpose of this study was to assess the knowledge and behaviors of health risks associated with a salt intake in adults with type 2 diabetes. This cross-sectional study was conducted among the type 2 diabetic in-patients of Bangladesh Institute of Health Sciences General Hospital, Dhaka, Bangladesh from October to December 2016. Data were collected from 131 respondents through interview using WHO STEPS module of salt with adaptation to local context like on amount of added salt while taking meal. Information on blood pressure, body mass index and relevant co-morbidities were also collected. About half of the respondents were women (56.5%). Mean age of the respondents was 54.3±14.4 years. More than six in 10 of them (62.6%) took added salt while taking meal; and 40.5% took processed foods with high salt. The mean amount of added salt intake among the users was 4.4±1.6gm per day having no significant difference between men and women. Though 47.3% of the respondents believed that lowering salt in meal is very important and 77.9% of them believed that excess salt or salty sauce can cause health problems. Salt intake behavior is poor in patients with type 2 diabetes even having regular contacts with doctors and other health professionals. Appropriate measures can be taken to increase awareness, change their attitude and behavior regarding salt consumption.

Prediction of ductus closure and development of adverse clinical outcome by functional echocardiography in very low birth weight newborn

OBJECTIVE

To evaluate the role of functional echocardiography for prediction of patent ductus arteriosus (PDA) closure and development of adverse outcome in very low birth weight newborn.

METHODS AND STUDY DESIGN

Functional echocardiography was done in 143 neonates with birth weight less than 1250 g on day 3. Nine echocardiographic parameters were analyzed for babies with PDA for prediction of spontaneous closure and development of one or more adverse outcomes (bronchopulmonary dysplasia, necrotizing enterocolitis≥stage 2 and intraventricular hemorrhage > grade 2) during hospital stay.

RESULT

The mean (±SD) birthweight and gestational age of the cohort were 1017 (±17) g and 30.8 (±2.7) weeks. PDA was found in 60 (41.9%) babies on day 3 among the recruited babies. Binary logistic regression model showed strong prediction ability of early (day 3) functional echocardiography markers in predicting future spontaneous closure of PDA and development of one or more adverse clinical outcome. In multivariate analysis, abnormal flow pattern (growing or pulsatile) was found to have increased risk for persistence of PDA (adjusted OR 22.9, CI 1.97-269) in comparison to PDA with closing/bidirectional pattern.

CONCLUSION

Early functional echocardiography, especially the flow pattern, is useful for prediction of PDA closure. Adverse clinical outcome prediction is possible with functional echocardiography markers when combined with gestational age and PDA closure status.

Effect of Annealing on Optical, Electrical and Charge Trapping Properties of TiO₂ NPs Arrays

Glancing angle deposition technique has been carried out to synthesize TiO₂ nanoparticles over SiO(x) thin film. The samples were annealed at different temperatures 550 °C and 950 °C. The average grain sizes and surface RMS roughness have been increased from 9 nm, 0.62 nm (as deposited); 21 nm, 2.47 nm (550 °C annealed) to 37 nm, 4.2 nm (950 °C annealed). Fivefold maximum increase in optical absorption has been recorded for the 950 °C annealed sample as compared to that of the as grown. The absorption and photoluminescence peaks show the red shift with an increase in annealing temperature and grain sizes. Transmission electron microscopy (TEM) has been used to investigate phases of nanoparticles. The junction capacitance of the Au/TiO₂ NPs device was observed to decrease with an increase in frequency. A minimum change in junction capacitance of 1 pF was calculated for 950 °C annealed device for the variation of frequency from 500 Hz to 1 MHz. The results are used to simulate the capacitance as a function of frequency and voltage characteristic of TiO₂ NPs based device in different temperature. Simulated results are exceptionally close to experimental results. The TiO₂ NPs based device annealed at 950 °C possessed higher impedance and lower conductance among all three type of devices. The sample annealed at 950 °C showed the maximum capacitance (0.09 pF at 0 V) as well as charge (˜0.6 Coulomb at +8 V) retention compared to that of the 550 °C annealed and as deposited samples.

Prevalence of Gingivitis, Plaque accumulation and Decayed, Missing and Filled Teeth among slum population in Bangladesh

A cross-sectional survey, using cluster sampling technique, of slum population, was done to explore the oral health status and the prevalence of common oral diseases. A close ended questionnaire comprising Decayed, Missing and Filled Teeth (DMFT) Index, Gingival Index (Löe and Silness) and Plaque Index was applied to evaluate and record oral diseases, in both male and female population, covering a wide range of age groups. Clinical examination was carried out in different slum set ups, including slum schools by trained and calibrated examiners. Three thousand nine hundred and four (3904) slum dwellers participated in the survey. Prevalence of Caries was expressed in mean DMFT, recording of gingival status followed the method of Löe and Silness, oral hygiene status was evaluated using Plaque index. Mean decayed component, of the DMFT, was significantly higher than filling and missing component. Both decayed and missing components showed increasing trend, and filling components decreased as the age progressed. Prevalence of gingivitis and plaque accumulation was remarkably high among slum dwellers. Significantly high level of common oral diseases was found among Tongi slum dwellers.Bangladesh Med Res Counc Bull 2014; 40 (2): 47-51

Characterization of Klebsiella granulomatis pathogenic to silkworm, Bombyx mori L

Bacterial disease of silkworm causes significant reduction of silk production leading to huge economic loss. This study aims to isolate bacteria from diseased silkworm and to determine its pathogenicity and antibiotic resistance. A strain of Klebsiella granulomatis has been isolated from silkworm haemolymph which was later identified on the basis of biochemical tests and 16S rRNA gene sequencing. The optimum culture condition of K. granulomatis was determined at pH 7.0 and 37 °C temperature. The strain was resistant to most of the antibiotics used in this study except azithromycin, gentamycin and ciprofloxacin. The strain is capable to reproduce flacherrie like symptoms with high mortality rate when re-injected into healthy silkworm. Treatment with low dose of ciprofloxacin was found to be effective to prevent flacherrie induced by the isolated K. granulomatis strain.

Tubular duplication of the oesophagus presenting with dysphagia

Duplications of the alimentary tract are rare congenital malformations, with the ileum being the most commonly affected site, followed by the oesophagus. Among oesophageal duplications, cystic duplication is the most common and the tubular variety, the rarest. Herein, we report a rare case of tubular oesophageal duplication, complicated by adenosquamous carcinoma at the lower end of the oesophagus, in a 32-year-old man who presented with progressive dysphagia. Although proton pump inhibitors may relieve dysphagia, oesophagectomy and gastric interpositioning should be the first-line treatment for patients with tubular oesophageal duplication, in order to reduce the risk of malignant transformation at the lower end of the oesophagus.

Neu-Laxova syndrome: a case report

Neu-Laxova syndrome (NLS) is a rare lethal syndrome found in both consanguinous and non-consanguinous couple. This is characterized by terrible face with unusual craniofacial appearance with exophthalmos, spectrum of central nervous system malformation, like microcaphaly, hypoplastic cerebellum, cleft lip/palate, ichthyosis and oedema. The diagnosis is made on the basis of clinical parameter. We report a 4 hour old male term newborn with IUGR of Neu-Laxova syndrome presented with anencephaly, rudimentary cerebellum, exophthalmos of right eye, bilateral cleft lip and palate and cryptorchidism. Anencephaly and cryptorchidism are two recently reported findings of NLS. We are presenting this case in addition from Bangladesh to lend further support to those two new findings as component of Neu-Laxova syndrome. Outcome of this syndrome is not good. Most of the patients are died of infection within hours to days.

Prevalence and determination of occupational diseases of

DOI: http://dx.doi.org/10.3329/ujzru.v31i0.15437Univ. j. zool. Rajshahi Univ. Vol. 31, 2012 pp. 79-82

Isozymic variations in specific and nonspecific esterase and its thermostability in silkworm, Bombyx mori L

Esterase isozymic variations were documented in the haemolymph of developed multivoltine and bivoltine silkworm breeds during unfavorable seed crop seasons of May - September using á- and â- napthylacetate separately to identify specific and nonspecific esterase having thermotolerant potentiality. Variations existed in the isozyme pattern with three bands (Est-2, 3 and 4) in pure Nistari race and other developed multivoltine and bivoltine breeds. Est-2 and Est-3 were non-specific esterases as they were observed when both á- and â-napthylacetate was used as substrates separately. Est-4 band was observed only with á-napthylacetate as substrate and was therefore confirmed to be specific á-esterase band in the haemolymph of silkworm, Bombyx mori L. Zymograms showed that the non-specific esterase band (Est-3) with R1 of 0.43 and specific á-esterase band (Est-4) with R(f) of 0.32 predominately withstood a temperature of 70 +/- 2 degrees C for a duration of 10 min and were confirmed as thermostable esterases in haemolymph of silkworm, Bombyx mori L. This also categorized the presence of thermostable esterases in developed multivoltine and bivoltine breeds of silkworm, even though the qualitative activity was more in the former than the latter. The qualitative presence of thermostable esterases and their activity could be adopted as an indicative biochemical marker in relation to thermotolerance in silkworm.

Prognostic factors for survival after curative resection of Dukes' B colonic cancer

AIM

Data on the prognostic factors for survival in patients with locally advanced, node-negative colon cancer are limited. This study aimed to determine which factors might predict survival in patients with Dukes' B (T3 or T4, N0) colon cancer.

METHOD

One hundred and eighty (93 male; median age 75 [range, 38-96] years) consecutive patients who had resection of a primary Dukes' B (on final histopathological analysis) colonic cancer between 1998 and 2003 were studied. No patient received neoadjuvant chemotherapy. Multivariate Cox regression modelling was used to assess the prognostic value of variables. Median follow up was 85 (60-125) months.

RESULTS

Thirteen (7%) patients had a perforation at presentation. The median distance from tumour to the nearest longitudinal resection margin was 6 (0.3-27) cm. One hundred and twenty-four (69%) patients had a lymph node yield of 12 or more nodes. Actual 5-year survival was 59%. On multivariate regression analysis, tumour perforation (perforation vs no perforation, 5-year survival, 23%vs 61%; hazard ratio (HR), 3.7; 95% confidence interval (CI), 1.6-8.4; P = 0.002), tumour-to-margin distance (< 5 cm vs ≥ 5 cm, 48%vs 65%; HR, 1.7; 95% CI, 1.1-2.7; P = 0.039) and older age (≥ 75 years vs < 75 years, 45%vs 72%; HR, 3; 95% CI, 1.8-5; P < 0.001) were independent significant variables.

CONCLUSION

A lymph node yield of 12 or more nodes is not a significant prognostic factor for survival after resection of Dukes' B colonic cancer. Patients with tumour perforation or limited resection have worse prognosis.

Bancroftian elephantiasis in Nilphamari, Bangladesh

The parasitic nematodes Wuchereria bancrofti, causes a dreadful disease in humans known as lymphatic filariasis, which afflicts more than 250 million people in tropical countries. Twelve districts with about 20 million people are endemic out of 64 districts in Bangladesh affecting more on Northern districts. This study was done in the Nilphamari, Kisorgonj and Sayedpur Thana under Nilphamari district, which is the most endemic for filariasis. In the present study, nineteen unions were investigated. Average 1.34% people were infected with filariasis (0.87% male and 1.81% female) out of 2,32,005 populations in those area. The highest percentage of infected unions was Alam Biditor (1.35%) under Kisorgonj Thana and lowest infected unions was Khatamadhupur (0.21%) under Sayedpur Thana. Among the affected people, 69.48% were poor, 28.88% were middle class and 1.63% was rich. The age group, 26-45 years, showed the highest rate (53.07%) of infection and the age group, 6-15 years, showed the lowest rate (1.92%) of infection. The relationships between infection status of male and female were statistically significant.

Influence of ghrelin and growth hormone deficiency on AMP-activated protein kinase and hypothalamic lipid metabolism

Current evidence demonstrates that the stomach-derived hormone ghrelin, a potent growth hormone (GH) secretagogue, promotes feeding through a mechanism involving the short-term activation of hypothalamic AMP-activated protein kinase (AMPK), which in turn results in decreased hypothalamic levels of malonyl-CoA and increased carnitine palmitoyltransferase 1 (CPT1) activity. Despite this evidence, no data have been reported about the effect of chronic, central ghrelin administration on hypothalamic fatty acid metabolism. In the present study, we examined the differences in hypothalamic fatty acid metabolism in the presence and absence of GH, by using a model for the study of GH-deficiency, namely the spontaneous dwarf rat and the effect of long-term central ghrelin treatment and starvation on hypothalamic fatty acid metabolism in this animal model. Our data showed that GH-deficiency induces reductions in both de novo lipogenesis and beta-oxidation pathways in the hypothalamus. Thus, dwarf rats display reductions in fatty acid synthase (FAS) mRNA expression both in the ventromedial nucleus of the hypothalamus (VMH) and whole hypothalamus, as well as in FAS protein and activity. CPT1 activity was also reduced. In addition, in the present study, we show that chronic ghrelin treatment does not promote AMPK-induced changes in the overall fluxes of hypothalamic fatty acid metabolism in normal rats and that this effect is independent of GH status. By contrast, we demonstrated that both chronic ghrelin and fasting decreased FAS mRNA expression in the VMH of normal rats but not dwarf rats, suggesting GH status dependency. Overall, these results suggest that ghrelin plays a dual time-dependent role in modulating hypothalamic lipid metabolism. Understanding the molecular mechanism underlying the interplay between GH and ghrelin on hypothalamic lipid metabolism will allow new strategies for the design and development of suitable drugs for the treatment of GH-deficiency, obesity and its comorbidities.

Amoebic liver abscess: presentation and complications

BACKGROUND

Amoebic liver abscess (ALA) is the most common inflammatory space occupying lesion of the liver. It has a highly variable presentation causing diagnostic difficulties. Untreated, complicated ALA has high morbidity and mortality.

OBJECTIVE

To study the various types of clinical presentation and complications of ALA in order to establish early diagnosis and prevent complications.

MATERIALS AND METHODS

A prospective study was conducted in the Department of Surgery of Calcutta National Medical College and Hospital from July 2005 to June 2008. All patients with a confirmed diagnosis of ALA during this period were included in the study.

RESULTS

Seventy-two patients with 76 ALAs were studied over a 3-year period. The age ranged from 21 to 72 years (mean age being 43.64 years). There were 66 males (91.67% of the patients) and 6 females (8.33% of the patients). The (31-40 years) age group showed the highest incidence consisting of 40.28% of the cases. Pain was located most commonly in the right hypochondrium in 60 patients (83.33%). Fever was observed in 58 patients (80.56%). Solitary abscess cavity was present in 68 patients (94.44%). The right lobe alone accounted for 65 (85.53%) of the abscesses. The most common echo pattern encountered in ultrasonography was the echorich pattern in 54 (71.05%) abscesses. Forty-four patients (61.11%) gave history of alcohol consumption. Diagnosis was missed in 21 patients (29.17%), particularly in those with atypical presentations. The most common complication was pleuropulmonary in 24 patients (33.33%), followed by intraperitoneal rupture in 19 patients (26.39%). Other complications were jaundice (n = 11), ascites (n = 9), subhepatic effusion (n = 7), subphrenic abscess (n = 3) and intrapleural rupture (n = 2). Ultrasonography was useful in diagnosing ALA. Despite successful therapy 23 patients (31.94%) had residual abscess cavities on ultrasonography even after 6 months.

CONCLUSION

In an endemic area a patient presenting with lower chest or upper abdominal pain along with tender hepatomegaly should raise the suspicion of ALA. Sonography remains an important tool in the diagnosis of ALA.

Pre-operative lymphoscintigraphy before sentinel lymph node biopsy for breast cancer

Pre-operative lymphoscintigram for axillary sentinel lymph node biopsy (SLNB) may not be required for successful SLNB. The 117 consecutive patients who underwent SLNB had pre-operative lymphoscintigraphy. The operating surgeon was blinded to the results of the lymphoscintigram before SLNB. After SLNB was complete, the surgeon was unblinded to the results of the lymphoscintigram; re-exploration carried out if more nodes were predicted on the lymphoscintigram. 116 patients (99%) had successful SLNB before unblinding. In 85 patients (73%), operative findings corresponded with scintigraphic findings. In 26 patients (22%), the lymphoscintigram predicted more sentinel nodes than had been found; further nodes were identified and excised in only 4 patients (3%). None were positive for cancer. SLNB was successful in 99% of cases without pre-operative lymphoscintigraphy. Only 3% of patients had further nodes identified as a result of the lymphoscintigram. Pre-operative lymphoscintigraphy does not improve the ability to perform axillary SLNB during breast cancer surgery.

Morbidity and mortality after closure of loop ileostomy

BACKGROUND

A temporary loop ileostomy is commonly used to protect low pelvic anastomoses. Closure is associated with morbidity and mortality. This study investigated patterns of complications after loop ileostomy closure and factors associated with morbidity and mortality.

METHOD

A review was performed of patients who underwent loop ileostomy closure between 1999 and 2005.

RESULTS

Three hundred and twenty-five patients underwent closure of loop ileostomy. Reasons for primary surgery were: anterior resection for cancer (n = 160, 49%), ileal pouch-anal anastomosis (n = 114, 35%), diverticular disease (n = 25, 8%), Crohn's colitis (n = 4, 1%) and other conditions (n = 22, 7%). Overall mortality was 2.5% (n = 8) and morbidity was 22.8% (n = 74). Thirty-two patients (10%) developed small bowel obstruction, of whom seven required operative intervention. Overall, the re-operation rate in this series was 28 patients (8.6%). Thirteen (4%) patients had an anastomotic leak of whom 12 patients had re-operation. Preoperative anaemia was significantly associated with leakage (Hb < 11 g/dl; n = 65, P = 0.033). The leakage rate was lower after a stapled anastomosis than a hand-sutured anastomosis (4/203 vs 9/122; P = 0.039). Hypo-albuminaemia (albumin < 34 g/l) was significantly associated with mortality (n = 46, P < 0.001).

CONCLUSIONS

Loop ileostomy closure is associated with morbidity and mortality. Anaemia and hypo-albuminaemia may be associated with poor outcome.

An unusual cause of haematuria

We report an unusual cause of haematuria in a young male patient due to leech in urinary bladder. The patient presented with undiagnosed haematuria of 12 days duration. Sonography is a safe and noninvasive procedure for diagnosis. Most of the leeches are micturated out spontaneously.

Mandibular osteomyelitis and multiple skeletal complications in Albers-Schönberg disease

Albers-Schönberg disease, or autosomal dominant osteopetrosis type II, is the most common form of the rare disease, osteopetrosis. Mandibular osteomyelitis is a rare complication of the disease. A host of other skeletal complications may also occur. Mandibular osteomyelitis along with bilateral severe coxa vara and pars fracture is very rare in Albers-Schönberg disease. We present the occurrence of these complications in a 24-year-old man with Albers-Schönberg disease. His mandibular osteomyelitis was successfully treated.

Impact of natural hosts and artificial adult diets on some quality parameters of the melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae)

Experiments were conducted to evaluate the impact of different natural hosts and artificial adult diets on the pupal quality, adult emergence, ovariole number and longevity of the melon fly, Bactrocera cucurbitae (Coquillett) for two generations under laboratory condition. Pupal quality and percentage adult emergence was slightly higher in F2 generation than F1 generation from all tested hosts. B. cucurbitae fed on proteose-peptone sugar (1:4) produced twice as many as eggs when fed on yeast:sugar (1:3). The differences in fecundity can be explained by the higher number of ovarioles and source of protein ingested. Highly significant interaction between adult diets and natural hosts was observed in terms of ovariole number of B. cucurbitae. Experimental results indicated the importance of understanding the genetic traits in the variation of ovariole number among natural populations of the fly spp.

Leptinomimetic effects of the AMP kinase activator AICAR in leptin-resistant rats: prevention of diabetes and ectopic lipid deposition

AIMS/HYPOTHESIS

Leptin has been shown to activate AMP-activated protein kinase (AMPK), an enzyme that regulates the activities of key enzymes of lipid synthesis and metabolism. We assess here (i) whether AMPK activity is diminished in rodents deficient in leptin or the leptin receptor, and (ii) the effects of treating the diabetes-prone, leptin-receptor-deficient Zucker Diabetic Fatty (ZDF) rat with an AMPK activator.

METHODS

AMPK activity and related parameters were measured in muscle and or liver of fa/fa and ZDF rats and ob/ob mice. We also explored the effect of treatment with the AMPK activator 5-aminoimidazole 4-carboxamide 1-beta-D ribofuranoside (AICAR) (7.4 mmol/l, on Monday, Wednesday and Friday for 15 weeks, beginning at 7 weeks of age) on the phenotype of the ZDF rat.

RESULTS

AMPK activity was diminished in muscle and/or liver of fa/fa (leptin-receptor-deficient, non-diabetic) and ZDF (leptin-receptor-deficient, diabetes-prone) rats and ob/ob mice (leptin-deficient). ZDF rats that had free access to food became hyperglycaemic (22.2 mmol/l) and hyperphagic after 2 to 5 weeks and remained so during the remainder of the study. Treatment of ZDF rats with AICAR prevented the development of diabetes, as well as increases of triglyceride content in liver, muscle and the pancreatic islets. It also attenuated the morphological abnormalities observed in the islets of untreated rats. Rats diet-matched with the AICAR-treated animals developed diabetes of intermediate severity and showed decreases in triglyceride content in the islets, but not in liver or muscle.

CONCLUSIONS/INTERPRETATION

The results indicate that a deficiency of leptin or the leptin receptor is associated with a decrease in AMPK activity in muscle and/or liver. They also suggest that treatment with an AMPK activator prevents the development of diabetes and ectopic lipid accumulation in the ZDF rat.

A case of chronic chest wall sinus

A 17-year-old Muslim female presented with a swelling over the chest wall underneath her left breast. The swelling was aspirated and the cytology report of the aspirated material showed it to be of pyogenic origin. An incision and drainage was done, after which the patient presented with a non-healing discharging sinus at the same site. The exact nature of the disease was known only after excising the sinus tract with the affected rib.

Leptospirosis and Weil's disease in eastern India

Leptospirosis is characterised by a broad spectrum of clinical manifestations varying from inapparent infection to fulminant fatal disease. Severe leptospirosis characterised by profound jaundice is referred to as Weil's disease. In the present study 20 patients of leptospirosis, of which 7 belonged to Weil's disease, were diagnosed based on the demonstration of IgM antileptospira antibody and supported by clinical correlation and appropriate biochemical markers. Overall, the male and female ratio was 17:3 and the same ratio for the Weil's disease was 6:1. The most common presentation involved fever, malaise and myalgia. Conjunctival congestion was found in 75% of the cases and jaundice was encountered in 90% of the cases. The prognosis of all these patients, including that of Weil's disease was excellent. Early recognition and initiation of antibiotic therapy were found to be important.

Effect of environmental fluctuations on the dynamic composition of engineered cartilage: A deterministic model in stochastic environment

Dynamics of extracellular matrix (ECM) deposition and scaffold degradation in cell-polymer constructs have been studied in a random fluctuating environment created due to the applications of growth factors into the in vitro generation of cartilaginous constructs. Existing models of cell-polymer constructs for the design of engineered cartilage have been discussed and then a new deterministic scheme in random environment proposed taking into account the effects of growth factors as the environmental variability in the form of Gaussian white noise. Steady-state probability distribution of each individual component of the ECM in its homeostasis is found explicitly. The computer-simulated results of the model have been discussed and then compared with the data from a variety of scaffold systems and culture conditions.

AMPK as a metabolic switch in rat muscle, liver and adipose tissue after exercise

An increasing body of evidence has revealed that activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK)-activated protein kinase increases fatty acid oxidation by lowering the concentration of malonyl coenzyme A (CoA), an inhibitor of carnitine palmitoyl transferase 1. Studies carried out primarily in skeletal muscle suggest that AMPK modulates the concentration of malonyl CoA by concurrently phosphorylating and inhibiting acetyl CoA carboxylase (ACC), the rate limiting enzyme in malonyl CoA synthesis, and phosphorylating and activating malonyl CoA decarboxylase (MCD), an enzyme involved in its degradation. We have recently observed that AMPK and MCD activities are increased and ACC activity diminished in skeletal muscle, liver and, surprisingly, in adipose tissue 30 min following exercise (treadmill run) in normal rats. In liver and adipose tissue these changes were associated with a decrease in the activity of glycerol-3-phosphate acyltransferase (GPAT), which catalyses the first committed reaction in glycerolipid synthesis and, which like ACC, is phosphorylated and inhibited by AMPK. Similar changes in ACC, MCD and GPAT were observed following the administration of 5-aminoimidazole 4-carboxamide-riboside (AICAR), further indicating that the exercise-induced alterations in these enzymes were AMPK-mediated.

CONCLUSIONS

(1) AMPK plays a major role in regulating lipid metabolism in multiple tissues following exercise. (2) The net effect of its activation is to increase fatty acid oxidation and diminish glycerolipid synthesis. (3) The relevance of these findings to the regulation of muscle glycogen repletion in the post-exercise state and to the demonstrated ability of AMPK activation to decrease adiposity and increase insulin sensitivity in rodents remains to be determined.

Dynamics of the cell and its extracellular matrix-a simple mathematical approach

The extracellular matrix (ECM) is produced by the cells and secreted into the surrounding medium, and consists of a complex mixture of structural and functional proteins. It has been recently observed that the ECM can influence the behavior of cell growth in vitro quite remarkably. A simple mathematical model has been constructed based on negative feedback control mechanisms to represent the dynamics of ECM deposition and cellular differentiation. The model analysis shows a strong relationship between the numerical solution and the experimental observations in cell-polymer constructs for the design of engineered cartilage. The current paper may be a useful guide for those who want to explore the studies on cell-matrix interactions.

Malonyl-CoA and AMP-activated protein kinase (AMPK): possible links between insulin resistance in muscle and early endothelial cell damage in diabetes

Based on available evidence, we would propose the following. (i) Excesses of glucose and free fatty acids cause insulin resistance in skeletal muscle and damage to the endothelial cell by a similar mechanism. (ii) Key pathogenetic events in this mechanism very likely include increased fatty acid esterification, protein kinase C activation, an increase in oxidative stress (demonstrated to date in endothelium) and alterations in the inhibitor kappa B kinase/nuclear factor kappa B system. (iii) Activation of AMP-activated protein kinase (AMPK) inhibits all of these events and enhances insulin signalling in the endothelial cell. It also enhances insulin action in muscle; however, the mechanism by which it does so has not been well studied. (iv) The reported beneficial effects of exercise and metformin on cardiovascular disease and insulin resistance in humans could be related to the fact that they activate AMPK. (v) The comparative roles of AMPK in regulating metabolism, signalling and gene expression in muscle and endothelial cells warrant further study.

A study of relapse after MDT in a district in West Bengal, India

A study was undertaken to estimate the magnitude of the problem of relapse and to identify factors responsible for relapse in leprosy units that were delivering MDT in Purulia District of West Bengal. From records patients were classified as "Relapse" or "Not relapse". "Not relapse" patients were selected by simple random sampling from the Surveillance Register and were matched according to age, sex, and the leprosy control unit. 128 cases ("Relapse") and 128 controls ("Not relapse") were interviewed in the clinic using a pre-tested questionnaire. Details of methods to identify and confirm relapse were circulated to all reporting units for ensuring uniformity and reliability. NGOs covered 42% of the population, while the State Government covered the remaining. The patients had been followed up after completion of treatment for a period of two years in PB leprosy and for five years in MB leprosy. The study revealed that the relapse rate was 1.71/1000 person-years for original PB cases and 0.76/1000 person-years for original MB cases. The study also showed that history of contact with an active leprosy patient and irregular treatment led more PB cases to relapse than control cases. All patients with an initial BI of 3+ relapsed with a BI of 1+ or 2+.

Microwave magnetoelectric particles: an experimental study of oscillating spectrums

One of the ways to uncover the nature of the microwave magnetoelectric (ME) effect, recently observed in small ferrite resonators with special-form surface metallizations, is a comparative analysis of oscillating spectrums excited by different type rf external fields. Experimental results of the ME coupling in different types of ferrite resonators and different types of surface electrodes are reported and some important conclusions are drawn observing the oscillating spectrums of those particles. A special interest in spectral properties of point ME particles should be found in the field of microwave artificial composite materials-bianisotropic materials.

Regulation of fatty acid oxidation and glucose metabolism in rat soleus muscle: effects of AICAR

Previous studies have shown that 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), a cell-permeable activator of AMP-activated protein kinase, increases the rate of fatty acid oxidation in skeletal muscle of fed rats. The present study investigated the mechanism by which this occurs and, in particular, whether changes in the activity of malonyl-CoA decarboxylase (MCD) and the beta-isoform of acetyl-CoA carboxylase (ACC beta) are involved. In addition, the relationship between changes in fatty acid oxidation induced by AICAR and its effects on glucose uptake and metabolism was examined. In incubated soleus muscles isolated from fed rats, AICAR (2 mM) increased fatty acid oxidation (90%) and decreased ACC beta activity (40%) and malonyl-CoA concentration (50%); however, MCD activity was not significantly altered. In soleus muscles from overnight-fasted rats, AICAR decreased ACC beta activity (40%), as it did in fed rats; however, it had no effect on the already high rate of fatty acid oxidation or the low malonyl-CoA concentration. In keeping with its effect on fatty acid oxidation, AICAR decreased glucose oxidation by 44% in fed rats but did not decrease glucose oxidation in fasted rats. It had no effect on glucose oxidation when fatty acid oxidation was inhibited by 2-bromopalmitate. Surprisingly, AICAR did not significantly increase glucose uptake or assayable AMP-activated protein kinase activity in incubated soleus muscles from fed or fasted rats. These results indicate that, in incubated rat soleus muscle, 1) AICAR does not activate MCD or stimulate glucose uptake as it does in extensor digitorum longus and epitrochlearis muscles, 2) the ability of AICAR to increase fatty acid oxidation and diminish glucose oxidation and malonyl-CoA concentration is dependent on the nutritional status of the rat, and 3) the ability of AICAR to diminish assayable ACC activity is independent of nutritional state.

Impact of modified leprosy elimination campaign in a MDT pilot project district of India

A study was carried out based upon the data available from National Leprosy Eradication Program of Purulia district in West Bengal. The result showed that the disease was in a declining trend up to the year 1998 and was inclining during the year 1998-1999 due to more case detection through MLEC-I, then followed by declining trend during the year 2000 as it was observed by MLEC-II. Single skin lesion rate was higher, MB rate was same and reduced deformity rate indicates early detection of cases due to better awareness of the community about the disease.

A versatile and inexpensive apparatus for rapid parallel synthesis on solid support: description and synthesis illustration

A new inexpensive and practical apparatus for solid-phase chemistry and parallel synthesis is described. This new apparatus fills an important void in the availability of portable tools for the synthesis of libraries of compounds in multi-milligram amounts. Individual reaction tube capacities range in size from 4 mL to 500 mL of operating liquid volume. Reaction blocks of 36 tubes x 4 mL or 24 tubes x 150 mL allow flexibility of operation. Insert tubes with frit ends function as filter sticks for resin wash and for maintenance of inert atmosphere. An electronic controller device connects to the reaction tubes for programmable entry of pulses of inert gas for resin mixing or vacuum for resin wash. The utility of this apparatus is illustrated by the synthesis of libraries based on 4-methaneamine imidazoles.

Evaluation of vestibular functions in otosclerosis before and after small fenestra stapedotomy

Vestibular functions in twenty-five patients with otosclerosis were analyzed before and after undergoing stapes surgery. Vertigo was present preoperatively in 6 patients, which disappeared completely after 4-6 weeks of surgery in all the patients indicating the usefulness of stapedectomy. Patients with otosclerosis demonstrated hypoexcitability compared to controls, which was statistically significant for right cold and hot irrigation. Our results showed equal culoric abnormalities in patients with mixed hearing loss and conductive loss. Patients with obliterative focus at surgery had impaired vestibular functions compared to non-obliterative foci without any statistical significance. A longer piston used at surgery tends to produce more vestibular damage compared to a smaller piston. Finally, the degree of vestibular dysfunction seems to be inversely proportional to the hearing result.

Novel antifungals based on 4-substituted imidazole: solid-phase synthesis of substituted aryl sulfonamides towards optimization of in vitro activity

The in vitro activity of novel 4-substituted imidazole antifungals was optimized by solid-phase chemistry and parallel synthesis. Potent yeast-selective as well as broad-spectrum antifungal compounds (32 and 20) were discovered.

Novel antifungals based on 4-substituted imidazole: a combinatorial chemistry approach to lead discovery and optimization

A series of 4-substituted imidazole sulfonamides has been prepared by solid-phase chemistry. These compounds were found to have good in vitro antifungal activity and constitute the first examples of C-linked azoles with such activity. The most potent inhibitor (30) demonstrated inhibition of key Candida strains at an in vitro concentration of < 100nM and compared favorably with in vitro potency of itraconazole.

Activation of malonyl-CoA decarboxylase in rat skeletal muscle by contraction and the AMP-activated protein kinase activator 5-aminoimidazole-4-carboxamide-1-beta -D-ribofuranoside

Alterations in the concentration of malonyl-CoA, an inhibitor of carnitine palmitoyltransferase I, have been linked to the regulation of fatty acid oxidation in skeletal muscle. During contraction decreases in muscle malonyl-CoA concentration have been related to activation of AMP-activated protein kinase (AMPK), which phosphorylates and inhibits acetyl-CoA carboxylase (ACC), the rate-limiting enzyme in malonyl-CoA formation. We report here that the activity of malonyl-CoA decarboxylase (MCD) is increased in contracting muscle. Using either immunopurified enzyme or enzyme partially purified by (NH(4))(2)SO(4) precipitation, 2-3-fold increases in the V(max) of MCD and a 40% decrease in its K(m) for malonyl-CoA (190 versus 119 micrometer) were observed in rat gastrocnemius muscle after 5 min of contraction, induced by electrical stimulation of the sciatic nerve. The increase in MCD activity was markedly diminished when immunopurified enzyme was treated with protein phosphatase 2A or when phosphatase inhibitors were omitted from the homogenizing solution and assay mixture. Incubation of extensor digitorum longus muscle for 1 h with 2 mm 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside, a cell-permeable activator of AMPK, increased MCD activity 2-fold. Here, too, addition of protein phosphatase 2A to the immunopellets reversed the increase of MCD activity. The results strongly suggest that activation of AMPK during muscle contraction leads to phosphorylation of MCD and an increase in its activity. They also suggest a dual control of malonyl-CoA concentration by ACC and MCD, via AMPK, during exercise.

Malonyl-CoA content and fatty acid oxidation in rat muscle and liver in vivo

Malonyl-CoA acutely regulates fatty acid oxidation in liver in vivo by inhibiting carnitine palmitoyltransferase. Thus rapid increases in the concentration of malonyl-CoA, accompanied by decreases in long-chain fatty acyl carnitine (LCFA-carnitine) and fatty acid oxidation have been observed in liver of fasted-refed rats. It is less clear that it plays a similar role in skeletal muscle. To examine this question, whole body respiratory quotients (RQ) and the concentrations of malonyl-CoA and LCFA-carnitine in muscle were determined in 48-h-starved rats before and at various times after refeeding. RQ values were 0.82 at baseline and increased to 0.93, 1. 0, 1.05, and 1.09 after 1, 3, 12, and 18 h of refeeding, respectively, suggesting inhibition of fat oxidation in all tissues. The increases in RQ at each time point correlated closely (r = 0.98) with increases (50-250%) in the concentration of malonyl-CoA in soleus and gastrocnemius muscles and decreases in plasma FFA and muscle LCFA-carnitine levels. Similar changes in malonyl-CoA and LCFA-carnitine were observed in liver. The increases in malonyl-CoA in muscle during refeeding were not associated with increases in the assayable activity of acetyl-CoA carboxylase (ACC) or decreases in the activity of malonyl-CoA decarboxylase (MCD). The results suggest that, during refeeding after a fast, decreases in fatty acid oxidation occur rapidly in muscle and are attributable both to decreases in plasma FFA and increases in the concentration of malonyl-CoA. They also suggest that the increase in malonyl-CoA in this situation is not due to changes in the assayable activity of either ACC or MCD or an increase in the cytosolic concentration of citrate.

Fatty acid oxidation and the regulation of malonyl-CoA in human muscle

Questions concerning whether malonyl-CoA is regulated in human muscle and whether malonyl-CoA modulates fatty acid oxidation are still unanswered. To address these questions, whole-body fatty acid oxidation and the concentration of malonyl-CoA, citrate, and malate were determined in the vastus lateralis muscle of 16 healthy nonobese Swedish men during a sequential euglycemic-hyperinsulinemic clamp. Insulin was infused at rates of 0.25 and 1.0 mU x kg(-1) x min(-1), and glucose was infused at rates of 2.0 +/- 0.2 and 8.1 +/- 0.7 mg x kg(-1) x min(-1), respectively. During the low-dose insulin infusion, whole-body fatty acid oxidation, as determined by indirect calorimetry, decreased by 22% from a basal rate of 0.94 +/- 0.06 to 0.74 +/- 0.07 mg x kg(-1) x min(-1) (P = 0.005), but no increase in malonyl-CoA was observed. In contrast, during the high-dose insulin infusion, malonyl-CoA increased from 0.20 +/- 0.01 to 0.24 +/- 0.01 nmol/g (P < 0.001), and whole-body fatty acid oxidation decreased by an additional 41% to 0.44 +/- 0.06 mg x kg(-1) x min(-1) (P < 0.001). The increase in malonyl-CoA was associated with 30-50% increases in the concentrations of citrate (102 +/- 6 vs. 137 +/- 7 nmol/g, P < 0.001), an allosteric activator of the rate-limiting enzyme in the malonyl-CoA formation, acetyl-CoA carboxylase, and malate (80 +/- 6 vs. 126 +/- 9 nmol/g, P = 0.002), an antiporter for citrate efflux from the mitochondria. Significant correlations were observed between the concentration of malonyl-CoA and both glucose utilization (r = 0.53, P = 0.002) and the sum of the concentrations of citrate and malate (r = 0.52, P < 0.001), a proposed index of the cytosolic concentration of citrate. In addition, an inverse correlation between malonyl-CoA concentration and fatty acid oxidation was observed (r = -0.32, P = 0.03). The results indicate that an infusion of insulin and glucose at a high rate leads to increases in the concentration of malonyl-CoA in skeletal muscle and to decreases in whole-body and, presumably, muscle fatty acid oxidation. Furthermore, they suggest that the increase in malonyl-CoA in this situation is due, at least in part, to an increase in the cytosolic concentration of citrate. Because cytosolic citrate is also an inhibitor of phosphofructokinase, an attractive hypothesis is that changes in its concentration are part of an autoregulatory mechanism by which glucose modulates its own use and the use of fatty acids as fuels for skeletal muscle.

Muscle lipid accumulation and protein kinase C activation in the insulin-resistant chronically glucose-infused rat

Chronic glucose infusion results in hyperinsulinemia and causes lipid accumulation and insulin resistance in rat muscle. To examine possible mechanisms for the insulin resistance, alterations in malonyl-CoA and long-chain acyl-CoA (LCA-CoA) concentration and the distribution of protein kinase C (PKC) isozymes, putative links between muscle lipids and insulin resistance, were determined. Cannulated rats were infused with glucose (40 mg. kg(-1). min(-1)) for 1 or 4 days. This increased red quadriceps muscle LCA-CoA content (sum of 6 species) by 1.3-fold at 1 day and 1.4-fold at 4 days vs. saline-infused controls (both P < 0.001 vs. control). The concentration of malonyl-CoA was also increased (1.7-fold at 1 day, P < 0.01, and 2.2-fold at 4 days, P < 0.001 vs. control), suggesting an even greater increase in cytosolic LCA-CoA. The ratio of membrane to cytosolic PKC-epsilon was increased twofold in the red gastrocnemius after both 1 and 4 days, suggesting chronic activation. No changes were observed for PKC-alpha, -delta, and -theta. We conclude that LCA-CoAs accumulate in muscle during chronic glucose infusion, consistent with a malonyl-CoA-induced inhibition of fatty acid oxidation (reverse glucose-fatty acid cycle). Accumulation of LCA-CoAs could play a role in the generation of muscle insulin resistance by glucose oversupply, either directly or via chronic activation of PKC-epsilon.

Cytosolic citrate and malonyl-CoA regulation in rat muscle in vivo

In liver, insulin and glucose acutely increase the concentration of malonyl-CoA by dephosphorylating and activating acetyl-CoA carboxylase (ACC). In contrast, in incubated rat skeletal muscle, they appear to act by increasing the cytosolic concentration of citrate, an allosteric activator of ACC, as reflected by increases in the whole cell concentrations of citrate and malate [Saha, A. K., D. Vavvas, T. G. Kurowski, A. Apazidis, L. A. Witters, E. Shafrir, and N. B. Ruderman. Am. J. Physiol. 272 (Endocrinol. Metab. 35): E641-E648, 1997]. We report here that sustained increases in plasma insulin and glucose may also increase the concentration of malonyl-CoA in rat skeletal muscle in vivo by this mechanism. Thus 70 and 125% increases in malonyl-CoA induced in skeletal muscle by infusions of glucose for 1 and 4 days, respectively, and a twofold increase in its concentration during a 90-min euglycemic-hyperinsulinemic clamp were all associated with significant increases in the sum of whole cell concentrations of citrate and/or malate. Similar correlations were observed in muscle of the hyperinsulinemic fa/fa rat, in denervated muscle, and in muscle of rats infused with insulin for 5 h. In muscle of 48-h-starved rats 3 and 24 h after refeeding, increases in malonyl-CoA were not accompanied by consistent increases in the concentrations of malate or citrate. However, they were associated with a decrease in the whole cell concentration of long-chain fatty acyl-CoA (LCFA-CoA), an allosteric inhibitor of ACC. The results suggest that increases in the concentration of malonyl-CoA, caused in rat muscle in vivo by sustained increases in plasma insulin and glucose or denervation, may be due to increases in the cytosolic concentration of citrate. In contrast, during refeeding after starvation, the increase in malonyl-CoA in muscle is probably due to another mechanism.

Malonyl-CoA, fuel sensing, and insulin resistance

Malonyl-CoA is an allosteric inhibitor of carnitine palmitoyltransferase (CPT) I, the enzyme that controls the transfer of long-chain fatty acyl (LCFA)-CoAs into the mitochondria where they are oxidized. In rat skeletal muscle, the formation of malonyl-CoA is regulated acutely (in minutes) by changes in the activity of the beta-isoform of acetyl-CoA carboxylase (ACCbeta). This can occur by at least two mechanisms: one involving cytosolic citrate, an allosteric activator of ACCbeta and a precursor of its substrate cytosolic acetyl-CoA, and the other involving changes in ACCbeta phosphorylation. Increases in cytosolic citrate leading to an increase in the concentration of malonyl-CoA occur when muscle is presented with insulin and glucose, or when it is made inactive by denervation, in keeping with a diminished need for fatty acid oxidation in these situations. Conversely, during exercise, when the need of the muscle cell for fatty acid oxidation is increased, decreases in the ATP/AMP and/or creatine phosphate-to-creatine ratios activate an isoform of an AMP-activated protein kinase (AMPK), which phosphorylates ACCbeta and inhibits both its basal activity and activation by citrate. The central role of cytosolic citrate links this malonyl-CoA regulatory mechanism to the glucose-fatty acid cycle concept of Randle et al. (P. J. Randle, P. B. Garland. C. N. Hales, and E. A. Newsholme. Lancet 1: 785-789, 1963) and to a mechanism by which glucose might autoregulate its own use. A similar citrate-mediated malonyl-CoA regulatory mechanism appears to exist in other tissues, including the pancreatic beta-cell, the heart, and probably the central nervous system. It is our hypothesis that by altering the cytosolic concentrations of LCFA-CoA and diacylglycerol, and secondarily the activity of one or more protein kinase C isoforms, changes in malonyl-CoA provide a link between fuel metabolism and signal transduction in these cells. It is also our hypothesis that dysregulation of the malonyl-CoA regulatory mechanism, if it leads to sustained increases in the concentrations of malonyl-CoA and cytosolic LCFA-CoA, could play a key role in the pathogenesis of insulin resistance in muscle. That it may contribute to abnormalities associated with the insulin resistance syndrome in other tissues and the development of obesity has also been suggested. Studies are clearly needed to test these hypotheses and to explore the notion that exercise and some pharmacological agents that increase insulin sensitivity act via effects on malonyl-CoA and/or cytosolic LCFA-CoA.

Double pylorus

We report a 55-year-old man presenting with postprandial epigastric pain and vomiting. Barium meal study suggested two openings from the stomach to the duodenum. Endoscopy revealed double pylorus with chronic duodenal ulcer, suggesting the second opening as an acquired one.

Malonyl CoA as a metabolic switch and a regulator of insulin sensitivity

Malonyl CoA is a regulator of carnitine palmitoyl transferase 1 (CPT1), the enzyme that controls the transfer of long chain fatty acyl CoA into mitochondria where it is oxidized. Recent studies indicate that in skeletal muscle the concentration of malonyl CoA is acutely (minutes) regulated by changes in its fuel supply and energy expenditure. In response to changes in fuel supply, regulation appears to be due to alterations in the cytosolic concentration of citrate, which is both an allosteric activator of acetyl CoA carboxylase (ACC), the enzyme that catalyzes malonyl CoA synthesis and a source of its precursor, cytosolic acetyl CoA. During exercise and immediately thereafter regulation by citrate appears to be lost and malonyl CoA levels diminish as the result of a decrease in ACC activity secondary to phosphorylation. Sustained increases in the concentration of malonyl CoA have been observed in muscle of a number of insulin-resistant rodents including the Zucker (fa/fa) and GK rats, KKAgy mice, glucose-infused rats and rats in which muscle has been made insulin resistant by denervation. Available data suggest that malonyl CoA could be linked to insulin resistance in these rodents by virtue of its effects on the cytosolic concentration of long chain fatty acyl CoA (LCFA CoA) and one or more protein kinase C isozymes. Whether similar alterations occur in other tissues and contribute to the pathophysiology of the insulin resistance syndrome remains to be determined.

Long-term exposure of beta-INS cells to high glucose concentrations increases anaplerosis, lipogenesis, and lipogenic gene expression

Chronic exposure of pancreatic beta-cells to high glucose has pleiotropic action on beta-cell function. In particular, it induces key glycolytic genes, promotes glycogen deposition, and causes beta-cell proliferation and altered insulin secretion characterized by sensitization to low glucose. Postglycolytic events, in particular, anaplerosis and lipid signaling, are thought to be implicated in beta-cell activation by glucose. To understand the biochemical nature of the beta-cell adaptive process to hyperglycemia, we studied the regulation by glucose of lipogenic genes in the beta-cell line INS-1. A 3-day exposure of cells to elevated glucose (5-25 mmol/l) increased the enzymatic activities of fatty acid synthase 3-fold, acetyl-CoA carboxylase 30-fold, and malic enzyme 1.3-fold. Pyruvate carboxylase and citrate lyase expression remained constant. Similar observations were made at the protein and mRNA levels except for malic enzyme mRNA, which did not vary. Metabolic gene expression changes were associated with chronically elevated levels of citrate, malate, malonyl-CoA, and conversion of glucose carbon into lipids, even in cells that were subsequently exposed to low glucose. Similarly, fatty acid oxidation was suppressed and phospholipid and triglyceride synthesis was enhanced independently of the external glucose concentration in cells preexposed to high glucose. The results suggest that a coordinated induction of glycolytic and lipogenic genes in conjunction with glycogen and triglyceride deposition, as well as increased anaplerosis and altered lipid partitioning, contribute to the adaptive process to hyperglycemia and glucose sensitization of the beta-cell.