Cardioprotection and the mitochondrial permeability transition

Although in developed countries, the rates of cardiovascular mortality show a decreasing trend, both the incidence and the prevalence of cardiovascular disease are on the rise in developing countries. It is likely that the currently unfolding epidemics of diabetes and obesity will erode recent gains in decreasing cardiovascular mortality in the Western countries as well. This article will focus on recent research which suggests that induction of mitochondrial permeability transition (MPT) during ischemia/ reperfusion (I/R) injury is a critical event that triggers both necrotic and apoptotic cell death. Additionally we will examine mechanisms that limit or prevent MPT which may be targeted to decrease ischemic cell death and to promote postischemic recovery of the heart. Nevertheless, the role of the mitochondria in myocardial I/R injury is complex and the signal transduction mechanisms that regulate MPT and its downstream consequences remain unclear and represent the current focus of several strategies of cardioprotection. Decades of exploration of the mitochondrial domains and the role of these organelles in regulating cell death and ischemic injury have brought us to a place where clinical interventions to limit infarct size seem to be realizable possibilities. The purpose of this review is to examine the possibility that inhibition of MPT may provide a clinically relevant target for decreasing I/R injury. Understanding MPT provide new insight into the role mitochondria play in decisions of cell survival and death.

Techniques to develop and characterize nanosized formulation for salbutamol sulfate

The present study relates to enhancing the dosing efficiency of pharmaceutical dry powder formulations administered by pulmonary inhalation. In particular, the study relates to the provision of dry powder inhalers (DPI) by forming nanosized particles of salbutamol sulfate (SBM) in order to augment the drug penetrability and deposition in the lungs. SBM, an antiasthmatic was selected to be developed into a nanosized formulation by different techniques like solvation, high-pressure homogenization, and spray drying, which were then compared on the basis of particle shape, particle size, and particle size distribution. In case of solvation method the nanosuspension was prepared by dispersing SBM into a nonsolvent and adding Tween-80 as a surfactant to prevent the agglomeration, the particles obtained therein were in the range of 2-10 mu. The second attempt was made by passing the suspension of SBM through high-pressure homogenizer at 10,000-15,000 psi. A treatment of six cycles of homogenization in presence of a Tween-80 as surfactant was found to give a nanosuspension within a size range 50-100 nm. The only drawback seemed with this technique was the low-product yield and high-processing time (3-4 h). In order to overcome this drawback spray-drying technique was further explored; the solution of SBM containing Tween-80 was stirred on magnetic stirrer at 1,200 rpm and finally dried by using spray dryer at an inlet and outlet temperature of 75 degrees C and 56 degrees C, respectively. The feed rate for spray dryer was kept to be 91 ml/h. The sample was collected and analyzed for particle size distribution which was found to be in the range of 50-100 nm. Keeping in view the positive outcomes in terms of higher yield and lower processing time, the spray-drying technique was taken to give the optimized formulation. Nanosized particles, thus obtained were evaluated for particle size, surface topology and particles size distribution, by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Quasi-elastic light scattering (QELS) technique, respectively. The nanosized particles were subjected to investigate changes on the physical stability of the powder, for this different analytical method was used as: Fourier transform infrared spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and X-ray diffraction (XRD) analysis and thus the result indicates that there was no physical disparity when compared with the commercial SBM sample.

Immunophenotypic and intracellular cytokine profile of Indian patients with tuberculosis with and without human immunodeficiency virus co-infection

BACKGROUND

Tuberculosis (TB) occurs in more than 50% of human immunodeficiency virus (HIV) infected Indian patients. This study was carried out to determine the immunophenotypic and intracellular cytokine profile of patients with HIV-TB co-infection.

PATIENTS AND METHODS

Fifteen patients with HIV-TB co-infection and 15 each with TB alone and healthy individuals were studied. Immunophenotypic analysis and intracellular cytokines were measured using appropriate antibodies on a flowcytometer.

RESULTS

Percentage of CD3+ did not differ significantly in the three groups. The ratio of CD4+ : CD8+ was reversed among patients with TB and HIV-TB. CD19+ and CD25+ were present on fewer cells of healthy individuals but this was not statistically significant. Significantly higher percentage of cells of patients with TB and HIV-TB were CD69 positive. Interferon-gamma (INF-gamma) and tumour necrosis factor-alpha (TNF-alpha) levels are significantly reduced in the CD4+ cells of patients with HIV-TB when compared with those with TB and healthy individuals. In CD8+ cells of patients with HIV-TB, levels of TNF-alpha are higher when compared with the other two groups. Interleukin-2 (IL-2) producing cells were not significantly different in any of the above subsets. Monocytes in individuals with HIV-TB had significantly higher interleukin-6 (IL-6) and TNF-alpha.

CONCLUSIONS

T-helper cells among patients with HIV-TB have significantly lower cytokine production. T-suppressor cells and monocytes produce more TNF-alpha. These findings may be significant in view of recent attempts to treat HIV-TB coinfected patients with anti-TNF therapy.

Vitamin D receptor gene polymorphism(s) and breast cancer risk in north Indians

BACKGROUND

Vitamin D (1,25-dihydroxyVitamin D3) has shown experimentally anticarcinogenic effects and is thought to protect against breast cancer. The actions of Vitamin D are mediated via the Vitamin D receptor (VDR), and the polymorphisms at 3'UTR region of this gene are associated with the risk and progression of breast carcinoma. The current study is an attempt to examine the association of these variations with breast cancer risk in north Indians.

METHODS

A total of 160 cases and 140 control subjects were studied for the polymorphisms at 3' end of the VDR gene. A polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method and fragment analysis was performed to determine ApaI and TaqI polymorphisms and variable length poly-A microsatellite repeats. Linkage disequilibrium (LD) was calculated for each pair of polymorphisms. Unadjusted and adjusted odds ratios for breast cancer with genotypes comprising the polymorphic sites were calculated to understand their role towards breast cancer susceptibility.

RESULTS

Patient's with long poly-A repeat showed a significant association with disease (chi 2 = 9.52, df = 2, P <or= 0.01). Compared to subjects having two S alleles (SS), odds ratios (and 95% CI) were 0.75 (0.45-1.23) and 2.49 (1.18-5.27) for subjects having genotypes SL and LL, respectively. Among matched pairs (age), the poly-A LL genotype was found significantly associated with increased risk of breast cancer among early-onset cases (P = 0.02). The unconditional logistic regression analysis demonstrated a significant association between grade and LL genotype [(unadjusted odds ratio (95% CI): 4.45 (1.87, 10.63); adjusted odds ratio: 4.66 (1.88, 11.53)]. No significant association was observed for the VDR ApaI (chi 2 = 1.00, df = 2, P = 0.60) and TaqI polymorphism (chi 2 = 0.35, df = 2, P = 0.83). Although, strong LD was not observed among these polymorphic sites, it denies the total equilibrium at the same time. Based on haplotype distribution, the most common one observed among cases and controls was ATS while, genotype AATTLL had shown a significant association with the breast cancer risk (P = 0.02).

CONCLUSIONS

The results indicate that the VDR poly-A polymorphism is significantly associated with breast cancer risk in north Indians especially with early onset disease. Although, ApaI and TaqI did not show any significant association with the disease when analyzed in isolation, but TaqI might modulate the risk associated with L alleles. Further, understanding the functional role of these variants residing on the VDR haplotype associated with disease susceptibility may suggest novel approaches for breast cancer prevention and therapy.

Resolvin D1 controls inflammation initiated by glutathione-lipid conjugates formed during oxidative stress

BACKGROUND AND PURPOSE

Inflammation is associated with oxidative stress and local generation of lipid peroxidation-derived aldehydes, such as 4-hydroxy-trans-2-nonenal (HNE). In most tissues, HNE is readily conjugated with glutathione and presently it is unknown whether glutathionyl-HNE (GS-HNE) plays a functional role in inflammation. Here, we sought to determine whether GS-HNE is a mediator of oxidative stress-initiated inflammation and if its actions can be regulated by the anti-inflammatory and pro-resolving lipid mediator, resolvin D1 (RvD1).

EXPERIMENTAL APPROACH

GS-HNE was administered intraperitoneally to mice and peritoneal lavages were assessed for leukocyte infiltration and lipid mediators were targeted by mediator-lipidomics. RvD1 was administered to mice treated with GS-HNE and leukocyte infiltration was assessed in the peritoneum. Superoxide production and CD11b modulation were measured in isolated human polymorphonuclear leukocytes incubated with GS-HNE.

KEY RESULTS

GS-HNE (1-10 microg) evoked infiltration of Gr-1(+) leukocytes into the peritoneum to form an inflammatory exudate. With isolated human polymorphonuclear leukocytes, GS-HNE stimulated both superoxide generation and CD11b expression. Among the lipid mediators, both cyclooxygenase- and lipoxygenase-derived pro-inflammatory eicosanoids, including prostaglandin E(2), leukotriene B(4) and cysteinyl leukotrienes, were generated in exudates of mice injected intraperitoneally with GS-HNE. RvD1, given i.v. in doses as low as 0.01-10.0 ng, sharply reduced GS-HNE-stimulated leukocyte infiltration ( approximately 30-70%).

CONCLUSIONS AND IMPLICATIONS

Glutathione conjugates of HNE, derived during oxidative stress, are pro-inflammatory in vivo. RvD1 protects against this oxidative stress-initiated inflammation.

Psoralen and ultraviolet A and narrow-band ultraviolet B in inducing stability in vitiligo, assessed by vitiligo disease activity score: an open prospective comparative study

BACKGROUND

Vitiligo is a common pigmentary disorder with great cosmetic and psychological morbidity and an unpredictable course. No treatment available is a definitive cure. Systemic psoralen and ultraviolet A (PUVA) has been the mainstay of treatment. Narrow-band UVB (NBUVB) was later introduced. In this study, we have compared the phototherapy modalities PUVA and NBUVB in inducing stability in vitiligo, assessed by using vitiligo disease activity score (VIDA), for the first time.

AIMS

To investigate the position of NBUVB vis-à-vis PUVA in terms of stability achieved during therapy as indicated by the VIDA scores.

SUBJECTS AND METHODS

It was an open, prospective study of 50 patients divided equally in PUVA and NBUVB groups. The study period was from January 2004 to June 2005. This study was done as a part of a larger project to compare the efficacy of mentioned modalities in degree of repigmentation.

RESULTS

In the NBUVB group, disease activity was present in 40% patients before commencement of therapy, which was reduced to 16% at the end of therapy (statistically significant, P = 0.049). In the PUVA group, similar figures were 20% and 16%, respectively. In the NBUVB group, 50% of patients whose disease was active prior to commencement of therapy had less than 50% repigmentation, whereas an equal number of patients had repigmentation of more than 50%. Almost an equal number of stable patients had less than and more than 50% repigmentation. In the PUVA group, 4 of the 5 (80%) patients who had active disease had less than 50% repigmentation, whereas only 1 patient (20%) with active disease obtained more than 50% repigmentation. The time to attain stability was 3.6 +/- 2.1 months in the NBUVB group and 3.22 +/- 3.1 months in the PUVA group. Eight of the 10 (80%) patients with unstable disease in the NBUVB group achieved stability, whereas 2 of the 5 (40%) patients of similar pre-treatment status in the PUVA group achieved stability.

CONCLUSION

NBUVB was in a more statistically advantageous position vis-à-vis PUVA, in respect to stability achieved and efficacy in both active and stable disease in a comparable time period.

Comparison of systemic PUVA and NB-UVB in the treatment of vitiligo: an open prospective study

BACKGROUND

Vitiligo is a common pigmentary disorder with great cosmetic and psychological morbidity. No treatment available is a definitive cure. Systemic psoralen and ultraviolet A (PUVA) has been the mainstay of treatment. Narrow-band ultraviolet B (NB-UVB) has been recently introduced. Although retrospective comparative study of systemic PUVA and NB-UVB has been published from our centre, no prospective study has been reported to date.

AIMS

To investigate the position of NB-UVB vis-à-vis PUVA in terms of efficacy, time to repigment and adverse effects and to help decide if one therapy has an advantage over another in the treatment of vitiligo.

SUBJECTS AND METHODS

It was a randomized, open, prospective study of 50 patients divided equally in TMP PUVA and NB-UVB groups. The study period was from January 2004 to June 2005.

RESULTS

The mean degree of repigmentation attained in the NB-UVB group was 52.24% over a mean treatment period of 6.3 months, whereas in the PUVA group it was 44.7% in a mean period of 5.6 months (P=0.144). After excluding the results of therapy-resistant sites, that is, hands and feet, the mean degree of repigmentation in the NB-UVB group was 67.57%, whereas in the PUVA group it was 54.2% (P=0.007).

CONCLUSIONS

NB-UVB performed better in comparison to TMP PUVA in terms of mean total repigmentation when traditionally considered therapy-resistant sites were excluded.

Efficacy of Deltamethrin and Cyfluthrin Impregnated Cloth over Uniform against Mosquito Bites

BACKGROUND

The difficulty with insecticide treated mosquito nets is that in military operation, it may not be practical for the personnel to carry mosquito nets with them. In mobile military operations, availability of pre-treated 'patches of cloth' or 'bands', which can be applied over the uniform at strategic sites, could be a feasible alternative.

METHODS

A double blind randomised controlled trial was undertaken among troops deployed in counter-insurgency operations in the northeastern parts of the country, to assess the efficacy of synthetic pyrethroid pretreated patches in reducing man mosquito contact, as compared to conventional repellents.

RESULT

The study indicated that pretreated patches, when affixed over the uniform, provided significantly higher protection from mosquito bites, when used in addition to the conventional repellents.

CONCLUSION

The study recommends that synthetic pyrethroid treated patches be made available to troops operating in highly malarious areas.

Effective heart disease prevention: lessons from a qualitative study of user perspectives in Bangladeshi, Indian and Pakistani communities

OBJECTIVES

Coronary heart disease (CHD) has a high mortality, incidence and prevalence among Indian, Pakistani and Bangladeshi communities in the UK, indicating the need for effective heart disease prevention initiatives for these communities. This paper considers how service user perspectives can be used to develop effective, culturally focused CHD prevention interventions for these target groups by addressing identified barriers, including deeply held cultural beliefs.

STUDY DESIGN

A qualitative research study, using a longitudinal action research approach.

METHODS

This was a community-based study in Edinburgh. Six focus group discussions--two for each community--were organized with participants from these communities at the beginning of the project. A further six focus group discussions for the same communities were organized six months later.

RESULTS

Over the period examined, participants reported varying changes in levels of knowledge relating to the nature, causes and symptoms of CHD. Some participants reported taking slight to significant steps to reduce or prevent heart disease, while others did not. The project was viewed as helpful in increasing knowledge about CHD and preventive measures and encouraging healthier lifestyles. However, persistent barriers to change were also identified, requiring changes to the project that involved not only matching intervention materials and messages to observable, superficial characteristics of the target population, but more fundamental changes that address the cultural, social, historical, environmental and psychological forces that influence health behaviour.

CONCLUSION

CHD prevention initiatives need to identify and respond to deep-rooted influences on health-behaviour in 'at-risk' groups, in addition to superficial characteristics of the target populations. It is important for specific prevention initiatives to be linked into wider CHD frameworks to ensure transferability of learning and integration within wider service provision.

Prevention of opportunistic infections in HIV infection by pentoxiphylline

BACKGROUND & OBJECTIVES

Levels of tumour necrosis factor (TNF) are increased in patients with HIV infection leading to increased apoptosis and reduced CD4 cell life. Pentoxiphylline is a TNF inhibitor with properties that might make it useful for the treatment of HIV infection. These include improved cell mediated immunity and inhibition of viral replication. We carried out this study to determine the therapeutic utility of pentoxiphylline in improving constitutional manifestations, preventing opportunistic infections and sustaining CD4 counts among asymptomatic HIV infected individuals (i.e., those with no opportunistic infection).

METHODS

Individuals with HIV infection who were over 18 yr of age and free of opportunistic infections were recruited in the study and followed up 4 weekly. CD4 counts were measured using a flowcytometer using anti-human CD4 intervals. Pentoxiphylline was prescribed in a dose of 400 mg thrice daily.

RESULTS

Thirty three (18 males) patients with HIV infection were studied. During their follow up (mean 12.5 +/- 5.6 months) one patient each developed cryptococcal meningitis and fibrocavitary tuberculosis. Weight increased from 51.3 +/- 7.4 kg at baseline to 55.3 +/- 7.4 kg (P<0.05). Malaise, fatigue and appetite improved in all those with these complaints, except the two with opportunistic infections. Mean CD4 counts were 184 +/- 36.4/microl at baseline and increased to 210 +/- 28.6/microl3 at four weeks (P<0.05). The patients had stable CD4 counts over the follow up period since then, i.e., within 25 per cent of the previous levels.

INTERPRETATION & CONCLUSION

Pentoxiphylline therapy in HIV infected individuals, who were free of opportunistic infections, improved their body weight, minimized opportunistic infections, increased and sustained CD4 counts. Given the low cost of the drug it could be recommended for the use in individuals who are at a high risk of developing opportunistic infections.

Acrolein generation stimulates hypercontraction in isolated human blood vessels

Increased risk of vasospasm, a spontaneous hyperconstriction, is associated with atherosclerosis, cigarette smoking, and hypertension-all conditions involving oxidative stress, lipid peroxidation, and inflammation. To test the role of the lipid peroxidation- and inflammation-derived aldehyde, acrolein, in human vasospasm, we developed an ex vivo model using human coronary artery bypass graft (CABG) blood vessels and a demonstrated acrolein precursor, allylamine. Allylamine induces hypercontraction in isolated rat coronary artery in a semicarbazide-sensitive amine oxidase activity (SSAO) dependent manner. Isolated human CABG blood vessels (internal mammary artery, radial artery, saphenous vein) were used to determine: (1) vessel responses and sensitivity to acrolein, allylamine, and H(2)O(2) exposure (1 microM-1 mM), (2) SSAO dependence of allylamine-induced effects using SSAO inhibitors (semicarbazide, 1 mM; MDL 72274-E, active isomer; MDL 72274-Z, inactive isomer; 100 microM), (3) the vasoactive effects of two other SSAO amine substrates, benzylamine and methylamine, and (4) the contribution of extracellular Ca(2+) to hypercontraction. Acrolein or allylamine but not H(2)O(2), benzylamine, or methylamine stimulated spontaneous and pharmacologically intractable hypercontraction in CABG blood vessels that was similar to clinical vasospasm. Allylamine-induced hypercontraction and blood vessel SSAO activity were abolished by pretreatment with semicarbazide or MDL 72274-E but not by MDL 72274-Z. Allylamine-induced hypercontraction also was significantly attenuated in Ca(2+)-free buffer. In isolated aorta of spontaneously hypertensive rat, allylamine-induced an SSAO-dependent contraction and enhanced norepinephrine sensitivity but not in Sprague-Dawley rat aorta. We conclude that acrolein generation in the blood vessel wall increases human susceptibility to vasospasm, an event that is enhanced in hypertension.

Acrolein induces vasodilatation of rodent mesenteric bed via an EDHF-dependent mechanism

Acrolein is generated endogenously during lipid peroxidation and inflammation and is an environmental pollutant. Protein adducts of acrolein are detected in atherosclerotic plaques and neurons of patients with Alzheimer's disease. To understand vascular effects of acrolein exposure, we studied acrolein vasoreactivity in perfused rodent mesenteric bed. Acrolein induced endothelium-dependent vasodilatation that was more robust and more sensitive than dilation induced by 4-hydroxy-trans-2-nonenal, trans-2-hexenal, or propionaldehyde. Acrolein-induced vasodilatation was mediated by K(+)-sensitive components, e.g., it was abolished in 0 [K(+)](o) buffer or in 3 mM tetrabutylammonium, inhibited 75% in 50 microM ouabain, and inhibited 64% in 20 mM K(+) buffer. Moreover, combined treatment with the Ca(2+)-activated K(+) channel inhibitors 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34, 100 nM) and apamin (5 microM) significantly reduced vasodilatation without altering sensitivity to acrolein. However, acrolein-induced % dilation was unaffected by l-NAME or indomethacin pretreatment indicating mechanistic independence of NO and prostaglandins. Moreover, acrolein induced vasodilatation in cirazoline-precontracted mesenteric bed of eNOS-null mice confirming eNOS independence. Pretreatment with 6-(2-propargyloxyphenyl) hexanoic acid (PPOH 50 microM), an epoxygenase inhibitor, or the superoxide dismutase mimetic Tempol (100 microM) significantly attenuated acrolein-induced vasodilatation. Collectively, these data indicate that acrolein stimulates mesenteric bed vasodilatation due to endothelium-derived signal(s) that is K(+)-, ouabain-, PPOH-, and Tempol-sensitive, and thus, a likely endothelium-derived hyperpolarizing factor (EDHF). These data indicate that low level acrolein exposure associated with vascular oxidative stress or inflammation stimulates vasodilatation via EDHF release in medium-sized arteries--a novel function.

Phase III trial of 5-fluorouracil and leucovorin plus either 3H1 anti-idiotype monoclonal antibody or placebo in patients with advanced colorectal cancer

BACKGROUND

The monoclonal antibody 3H1 mimics the external structure of the carcinoembryonic antigen (CEA). It therefore has the potential, via the anti-idiotypic network, to stimulate immune responses to CEA that may benefit colorectal cancer patients.

PATIENTS AND METHODS

A total of 630 patients with previously untreated metastatic colorectal cancer were randomised in a 2:1 fashion to receive bolus 5-fluorouracil (5-FU) and leucovorin (LV) plus either 3H1 (n = 422) or placebo (n = 208).

RESULTS

The addition of 3H1 to 5-FU and LV did not result in increased toxicity. Survival for the full intent-to-treat population was 14.7 months for the 3H1 arm and 15.2 months for the placebo arm (P = 0.80). Anti-CEA antibody responses were observed in 70% of patients treated with 3H1. Patients with a negative CEA response had a median survival of 8.3 months (95% CI 7.5-11.0) compared with patients with a strong response: median survival not reached (P <0.001).

CONCLUSION

3H1 is safe and effectively induces immune responses to CEA. Addition of 3H1 to 5-FU and LV was not shown to improve overall patient outcomes. However, improved survival in patients developing anti-CEA responses to 3H1 are provocative and should be studied in further clinical trials.