Activity of ectonucleotidases and adenosine deaminase in rats exposed to cigarette smoke

Cigarette smoke is a complex mixture of various toxic substances that are capable of initiating oxidative damage and promoting blood platelet alterations. In this study, we investigated the activities of the ectoenzymes NTPDase (ectonucleoside triphosphate diphosphohydrolase, CD39) and 5'-nucleotidase (CD73) in platelets as well as adenosine deaminase (ADA) in the plasma of rats exposed to aged and diluted sidestream smoke during 4 weeks. The rats were divided into two groups: I (control) and II (exposed to smoke). After the exposure period, blood was collected and the platelets and plasma were separated for enzymatic assay. The results demonstrated that NTPDase (with ATP as substrate) and 5'-nucleotidase (AMP as substrate) activities were significantly higher in group II (p < 0.05) as compared to group I, while no significant difference was observed for NTPDase with ADP as substrate. The ADA activity was significantly reduced in group II (p < 0.05) as compared with group I. Platelet aggregation was significantly increased in group II (p < 0.05) as compared with group I. We suggest that these alterations in the activity of enzymes from the purinergic system are associated with an increase in platelet aggregation. However, our study has demonstrated that the organism tries to compensate for this enhanced aggregation by increasing hydrolysis of AMP and reducing hydrolysis of adenosine, a potent inhibitor of aggregation and an important modulator of vascular tone.

RF tumour ablation: Computer simulation and mathematical modelling of the effects of electrical and thermal conductivity

This study determined the effects of thermal conductivity on RF ablation tissue heating using mathematical modelling and computer simulations of RF heating coupled to thermal transport. Computer simulation of the Bio-Heat equation coupled with temperature-dependent solutions for RF electric fields (ETherm) was used to generate temperature profiles 2 cm away from a 3 cm internally-cooled electrode. Multiple conditions of clinically relevant electrical conductivities (0.07-12 S m-1) and 'tumour' radius (5-30 mm) at a given background electrical conductivity (0.12 S m-1) were studied. Temperature response surfaces were plotted for six thermal conductivities, ranging from 0.3-2 W m-1 degrees C (the range of anticipated clinical and experimental systems). A temperature response surface was obtained for each thermal conductivity at 25 electrical conductivities and 17 radii (n=425 temperature data points). The simulated temperature response was fit to a mathematical model derived from prior phantom data. This mathematical model is of the form (T=a+bRc exp(dR) s(f) exp(g)(s)) for RF generator-energy dependent situations and (T=h+k exp(mR)+n?exp(p)(s)) for RF generator-current limited situations, where T is the temperature (degrees C) 2 cm from the electrode and a, b, c, d, f, g, h, k, m, n and p are fitting parameters. For each of the thermal conductivity temperature profiles generated, the mathematical model fit the response surface to an r2 of 0.97-0.99. Parameters a, b, c, d, f, k and m were highly correlated to thermal conductivity (r2=0.96-0.99). The monotonic progression of fitting parameters permitted their mathematical expression using simple functions. Additionally, the effect of thermal conductivity simplified the above equation to the extent that g, h, n and p were found to be invariant. Thus, representation of the temperature response surface could be accurately expressed as a function of electrical conductivity, radius and thermal conductivity. As a result, the non-linear temperature response of RF induced heating can be adequately expressed mathematically as a function of electrical conductivity, radius and thermal conductivity. Hence, thermal conductivity accounts for some of the previously unexplained variance. Furthermore, the addition of this variable into the mathematical model substantially simplifies the equations and, as such, it is expected that this will permit improved prediction of RF ablation induced temperatures in clinical practice.

Immunomodulatory Therapy for Vogt-Koyanagi-Harada Patients as First-Line Therapy

PURPOSE

To report on the use of immunomodulatory therapy (IMT) in a group of patients with Vogt-Koyanagi-Harada disease (VKH) and to compare the outcomes with those of another group of patients with VKH who were treated for prolonged periods with corticosteroids.

METHODS

Treatment regimens and their respective outcomes (visual acuity) were compared for the following groups: prolonged steroid with or without delayed addition of IMT (Group 1) and relatively prompt IMT with or without steroid (Group 2).

RESULTS

The average duration of follow-up in Group 1 was 28.9 months and in Group 2 23.4 months. In Group 1, visual acuity deteriorated in three of the five patients (60%) and improved in one (20%). The fifth patient showed improvement in visual acuity in one eye, but decreased visual acuity in the other eye. In Group 2, seven of the eight patients showed improvement in their visual acuities (87.5%); visual acuity deteriorated in one patient (12.5%).

CONCLUSIONS

The results suggest that IMT as first-line therapy for VKH is associated with a superior visual outcome when compared to steroid as monotherapy or with delayed addition of IMT.

The molecular landscape of ASPM mutations in primary microcephaly

BACKGROUND

Autosomal recessive primary microcephaly (MCPH) is a model disease to study human neurogenesis. In affected individuals the brain grows at a reduced rate during fetal life resulting in a small but structurally normal brain and mental retardation. The condition is genetically heterogeneous with mutations in ASPM being most commonly reported.

METHODS AND RESULTS

We have examined this further by studying three cohorts of microcephalic children to extend both the phenotype and the mutation spectrum. Firstly, in 99 consecutively ascertained consanguineous families with a strict diagnosis of MCPH, 41 (41%) were homozygous at the MCPH5 locus and all but two families had mutations. Thus, 39% of consanguineous MCPH families had homozygous ASPM mutations. Secondly, in 27 non-consanguineous, predominantly Caucasian families with a strict diagnosis of MCPH, 11 (40%) had ASPM mutations. Thirdly, in 45 families with a less restricted phenotype including microcephaly and mental retardation, but regardless of other neurological features, only 3 (7%) had an ASPM mutation. This report contains 27 novel mutations and almost doubles the number of MCPH associated ASPM mutations known to 57. All but one of the mutations lead to the use of a premature termination codon, 23 were nonsense mutations, 28 deletions or insertions, 5 splicing, and 1 was a translocation. Seventeen of the 57 mutations were recurrent. There were no definitive missense mutations found nor was there any mutation/phenotype correlation. ASPM mutations were found in all ethnic groups studied.

CONCLUSION

This study confirms that mutations in ASPM are the most common cause of MCPH, that ASPM mutations are restricted to individuals with an MCPH phenotype, and that ASPM testing in primary microcephaly is clinically useful.

In vitro antimicrobial and cytotoxic activities of leaves and flowers extracts from Lippia alba

The research was conducted to investigate the in vitro antimicrobial and cytotoxic activities of leaves and flowers extract extracted from Lippia alba. Disc diffusion technique was used for in vitro antibacterial and antifungal screening. Zones of inhibition were observed in disc diffusion for antibacterial screening against 4 Gram-positive pathogenic and 6 Gram-negative pathogenic bacteria. Among crude extracts chloroform extract showed good activity against all test organisms. A Large zone of inhibition was observed (18 mm) against Vibrio parahaemolyticus. In antifungal screening, the compound showed mild to moderate zones of inhibition against four tested organisms. A Large zone of inhibition was observed against Aspergillus niger (13 mm). Cytotoxic activities of crude extracts were determined using Brine shrimp lethality Bioassay and LC50 values of standard Vincristin sulphate as positive control, n-hexane and crude ethanol extracts were found to be 5, 15 and 20 microg mL(-1), respectively.

High prevalence of hepatitis A virus antibody among Bangladeshi children and young adults warrants pre-immunization screening of antibody in HAV vaccination strategy

Serum samples from 465 subjects aged between 1 and 25 years were tested for antibody against hepatitis A virus (HAV) [anti-HAV IgG and IgM] to determine the seroprevalence of HAV antibody and do a cost-benefit analysis for decision making about vaccination against HAV among the general population of Bangladesh. A high prevalence of anti-HAV (74.8%) was observed in the study population; the whole study population was found positive for anti-HAV by the age of 25 years. On performing the cost-benefit analysis, it was found that the cost for vaccination with screening for anti-HAV was almost three times cheaper than vaccination without screening. Thus, in the present socioeconomic condition of Bangladesh, a policy based on screening for HAV antibody before vaccination is recommended.

Profile of non traumatic surgical disorders found in the pilgrims/trekkers travelling to Shri Amarnath Ji cave

BACKGROUND & OBJECTIVES

The "Shri Amarnath Ji Yatra" is an annual congregation in which the devotees trek a difficult route of around 40 km to reach to a cave at a height of approximately 14,000 feet at Pahalgam in the State of Jammu & Kashmir, India. These trekkers are subjected to stress and strain of the long mountainous route and difficult security scenario as a result of which they are prone to develop some surgical disorders. We ascertained the profile of non-traumatic surgical conditions met in these people at the various medical aid centres and the base hospital Pahalgam so that a policy could be framed to prevent these conditions.

METHODS

This study was conducted at the Government Base Hospital Pahalgam, Kashmir, between June and August 2006. The patients with non traumatic surgical conditions attending the hospital were included in this study. Necessary investigations were done and patients requiring surgical intervention were operated upon.

RESULTS

Of the 1,54,000 devotees who undertook the "yatra", in 2006 the personnel of the Directorate of Health Services, Kashmir, extended medical aid to 40,082 pilgrims. Of these 40,082 pilgrims, 172 were admitted on the surgical side for various non traumatic surgical disorders. The commonest cause for admission was exacerbation of acid peptic diseases. Nine emergency surgical procedures were conducted at the base hospital and the commonest cause for intervention was perforation of a duodenal ulcer. There was no mortality and the patients responded well to conservative ulcer procedures.

INTERPRETATION & CONCLUSION

The stress of high altitude trekking and assembly of a large gathering of people during the annual "Amarnath Ji yatra" can pose a number of health related problems especially in the old and infirm people as was observed in the study. Pilgrims who intend taking up the yatra in future should seek medical advice prior to their departure. If a person is diagnosed to have peptic ulcer disease he or she should be put on anti-ulcer therapy to prevent potential complications.

Potential of nanoemulsions for intravenous delivery of rifampicin

The aim of the present study was to develop, characterize and evaluate nanoemulsion formulations for intravenous delivery of rifampicin (RIF). Different oil-in-water (o/w) nanoemulsions were prepared by the aqueous phase titration method. Prepared nanoemulsions were subjected to thermodynamic stability tests for phase separation, creaming, cracking, coalescence or phase inversion and dispersibility test for dilution capacity. Nanoemulsion formulations which passed these tests were characterized in terms of droplet size, viscosity, entrapment efficiency, homogeneity and pH. The selected formulations were subjected to in vitro dissolution studies using a dissolution apparatus-XXIII in dialysis bag. Best results were obtained with the formulation which consisted of 150 mg of RIF, 15% w/w of Sefsol 218, 18.75% w/w of Tween 80, 6.25% w/w of Tween 85 and 60% w/w of normal saline. The optimized formulation was also subjected to stability studies according to the ICH guidelines. The formulation was found to be stable for more than19 months. These results indicated the potential of nanoemulsions for intravenous delivery of RIF.

Diabetes in post genomic era: promises to discover biomarkers and new drug targets

The complementary disciplines of genomics and proteomics offer better insights into the molecular mechanisms of diseases. Whilst genomics hunts for defining our static genetic substrate, proteomics explores the structure and function of proteins expressed by a cell or tissue type under specified conditions. In the past decade, proteomics has been revolutionized by the application of techniques such as two-dimensional gel electrophoresis (2-DGE), mass spectrometry and protein arrays. These techniques have tremendous potential for biomarker development, target validation, diagnosis, prognosis, and optimization of treatment in medical care, especially in the field of diabetes. This mini review will highlight the contributions of proteomic technologies towards the discovery of potentially new biomarkers for pathophysiological mechanisms and clinical outcome of diabetes.

Sequential induction chemotherapy followed by radical chemo-radiation in the treatment of locoregionally advanced head-and-neck cancer

We describe a retrospective series of patients with advanced head-and-neck cancer who were treated with induction chemotherapy followed by radical chemo-radiation. Patients treated with two cycles of induction chemotherapy followed by definitive chemo-radiation for squamous cell carcinoma of the head-and-neck region, from 2001 – 2006 at the Royal Marsden Hospital, formed the basis of this study. Cisplatin (75 mg m⁻²) on day 1 and 5-FU (1000 mg m⁻²) day 1 – 4 was the standard regimen used for induction treatment. Cisplatin (100 mg m⁻²) on day 1 and day 29 was used for concomitant treatment. The radiation was delivered using conformal technique. Tissues containing macroscopic and microscopic disease were treated to doses of 65 Gray (Gy) in 30 fractions and 50 Gy in 25 fractions, respectively. Data on patterns of relapse and acute toxicity (NCICTCv.3.0) were collected. A total of 129 patients were included, median age was 58 (range: 27 – 78). The site of tumour was: oropharynx 70 (54%), larynx 30 (23%), hypopharynx 24 (19%) and other 5 (4%). The median follow-up was 19 months (range: 4 – 58). Local control, disease-specific survival and overall survival at 2 years were 71%, 68% and 63%, respectively. The distant recurrence rate at 2 years was 9%. Ten patients required dose reduction during induction chemotherapy due to toxicity. The dose of 5-FU was reduced in six patients and that of cisplatin in four patients. The incidence of grade 3/4 toxicity was: neutropenia 5%, thrombocytopenia 1%, nausea and vomiting 3%. One cycle of concurrent cisplatin was omitted in 23 patients due to toxicity. Full-dose radiotherapy was administered to 98% of patients. The incidence of grade 3/4 toxicity was: skin 20%, dysphagia 65%, mucositis 60%, neutropenia 3%, anaemia 1%, nausea and vomiting 4%, nephrotoxicity 1%. Induction chemotherapy followed by radical chemo-radiation is a safe and tolerable regimen in the treatment of advanced head-and-neck cancer. Distant recurrence rates are lower with equivalent local control and survival compared to chemo-radiation alone (historical controls).