Prevalence of lymphatic filariasis in a tea garden worker population of Dibrugarh (Assam), India after six rounds of mass drug administration.

BACKGROUND & OBJECTIVES: Lymphatic filariasis (LF) is endemic in the state of Assam and mass drug administration (MDA) programme for LF elimination is being implemented in the state since 2004. A study on prevalence of microfilaria (mf), disease endemicity and vector infection was carried out in a tea garden population of Dibrugarh, Assam (India) to assess the effect of ongoing MDA programme on elimination of LF. METHODS: Finger prick thick blood smears (20 mm3) were made from individuals aged ≥2 yr old during night blood survey in between 2000-0000 hrs during the period of November 2012 to February 2013. Blood smears were dehaemoglobinised, stained with Giemsa and examined under microscope for presence of mf. Indoor resting mosquitoes were collected during 0600-1000 hrs and female Culex quinquefasciatus were dissected and examined under microscope for larval forms of the parasite. RESULTS: A total of 634 blood smears were collected and screened for mf and 47 (7.41%) individuals were found microfilaraemic, with predominance of males (74.5%). Highest mf rate (20.0%) was seen in the males of 30-39 yr age group while in females, age group of 10-19 yr recorded maximum mf rate (5.48%). Entomological collection and dissection of Cx. quinquefasciatus revealed presence of larval stages of the parasite and infection and infectivity rates recorded were 13.20 and 3.70%, respectively. Chronic clinical manifestations in the form of elephantiasis and hydrocele were recorded in 33 (5.73%) subjects of the 575 examined. INTERPRETATION & CONCLUSION: Mass drug administration data showed six rounds of MDA with drug distribution coverage in between 63.42 and 95.93% in the study population. Out of 634 individuals examined 47 were found microfilaraemic giving an overall infection rate of 7.41%. Mosquito vector infection and infectivity rates were 13.20 and 3.70%, respectively. Presence of high mf rate, vector infectivity rate and clinical cases in the study population after six rounds of MDA warrants concerted efforts to be made for effective implementation and monitoring of MDA for success of LF elimination programme.

Microfilarial periodicity of Wuchereria bancrofti in Assam, Northeast India.

BACKGROUND & OBJECTIVES: Wuchereria bancrofti has shown nocturnal periodicity in India and other endemic countries of the world except pacific regions where non-periodic or diurnal sub-periodic forms have been reported. Presence of sub-periodic form of W. bancrofti in Andaman and Nicobar Islands, India and a case report of sub- periodic form of W. bancrofti from Mysore, India provide basis for exploring the periodicity pattern of microfilaria of W. bancrofti prevalent in Assam, Northeastern region of India. State of Assam has unique geographical location as its Northeastern region shares international boundaries with Nepal, China, Bhutan, Myanmar and Bangladesh. Evolutionary association of W. bancrofti found in Assam is not known and possibility of its link with W. bancrofti form, prevalent in neighbouring countries may not be ruled out. Hence, this study was undertaken to know the microfilarial periodicity of W. bancrofti in Assam. METHODS: Ten microfilaria positive adult male individuals having moderate to high microfilaraemia were selected. Informed written consent from each participant was obtained. The presence of microfilaria was observed at two hourly intervals over a period of 24 h using 50 µl of finger prick peripheral blood samples. Peripheral blood smears were processed, stained and examined under microscope and microfilaria counts were recorded. RESULTS: Data collected were calculated and analyzed using modified statistical method, and the periodicity curve was prepared. Typical nocturnal periodicity was observed at a peak time of 0003 hrs with a periodicity index of 136.2. INTERPRETATION & CONCLUSION: Analysis of the data revealed nocturnal periodicity of the W. bancrofti prevalent in the Assam with peak periodicity about one hour ahead of the other states in India. Findings will be helpful in evaluation and monitoring of ongoing MDA programme for elimination of LF in Assam.

Long-term effect of Trigonella foenum graecum and its combination with sodium orthovanadate in preventing histopathological and biochemical abnormalities in diabetic rat ocular tissues.

Trigonella foenum graecum seed powder (TSP) and Sodium Orthovanadate (SOV) have been shown to demonstrate antidiabetic effects by stabilizing glucose homeostasis and carbohydrate metabolism in experimental type-1 diabetes. However their efficacy in controlling histopathological and biochemical abnormalities in ocular tissues associated with diabetic retinopathy is not known. The purpose of this study was to investigate the comparative efficacy of individual as well as combination therapy of TSP and SOV in 8 weeks diabetic rat lens and retina. Retinas and lenses were taken from control, alloxan-induced diabetic rats and diabetic rats treated separately with insulin, 5%TSP, SOV (0.6 mg/ml) and a combined dose of SOV (0.2 mg/ml) and 5%TSP for 60 days. Control and each experimental group had six rats. Alterations in the activities of enzymes HK (hexokinase), AR (aldose reductase), SDH (sorbitol dehydrogenase), G-6-PD (glucose-6-phosphate dehydrogenase), GPx (glutathione peroxidase), GR (glutathione reductase) and levels of metabolites like sorbitol, fructose, glucose, MDA (malondialdehyde) and GSH (reduced glutathione) were measured in the cytosolic fraction of lenses besides measuring blood glucose levels and glycosylated haemoglobin. Histopathological abnormalities were studied in the lens using photomicrography and retina using transmission electron microscopy. Blood glucose, glycosylated haemoglobin levels and polyol pathway enzymes AR and SDH increased significantly causing accumulation of sorbitol and fructose in the diabetic lens and treatment with SOV and TSP significantly (p < 0.05) decreased these to control levels. Similarly, SOV and TSP treatments modulated the activities of HK, G-6-PD, GPx and GR in the rat lens to control values. Ultrastructure of the diabetic retina revealed disintegration of the inner nuclear layer cells with reduction in rough endoplasmic reticulum and swelling of mitochondria in the bipolar cells; and these histopathological events were effectively restored to control state by SOV and TSP treatments. In this study SOV and TSP effectively controlled ocular histopathological and biochemical abnormalities associated with experimental type-1 diabetes, and a combination regimen of low dose of SOV with TSP demonstrated the most significant effect. In conclusion, the potential of SOV and TSP alone or in low dose combination may be considered as promising approaches for the prevention of diabetic retinopathy and other ocular disorders.

Antiatherosclerotic effects of dietary supplementations of garlic and turmeric: Restoration of endothelial function in rats.

Protections of endothelial integrity by elimination of certain risk have proven to be effective in maintaining hemostasis and in slowing the progress of the cardiovascular disease. Indigenous drugs are the natural source of protection against these disorders, which can be used more effectively by the knowledge of their active ingredients as well as by their mechanism of action. Most prominent among these drugs are garlic, [Alium sativum L., Family: Liliaceae, Bulbs] and turmeric [Curcuma longa L., Family: Zingiberaceae, Rhizomes]; commonly used Indian traditional spices. In the present study, we examined the atheroscleroprotective potential of diet supplementation of garlic and turmeric by measuring serum lipid profile, changes in cardiovascular parameters i.e. arterial blood pressure, electrocardiogram and heart rate. We further tried to elucidate the mechanism of restoration of endothelial function and the role of endothelium-derived factors mainly, nitric oxide (NO) and cycloxygenase derived contracting factors. A notable restoration of arterial blood pressure was seen in animals on garlic and turmeric supplemented diet. Animals on supplemented diet showed a significantly enhanced vasorelaxant response to adenosine, acetylcholine, isoproterenol and contractile effect of 5-hyderoxytryptamine was significantly attenuated. Inhibition of these responses by L-NMMA was smaller in tissues from herbal treated animals. Incubation of tissues with L-arginine (10(-5) M) resulted in a significant reversal of L-NMMA induced inhibition of endothelium-mediated relaxation, which appeared to be pronounced in rings from animals supplemented with herbs as compared to hypercholesterolemic animals. Addition of indomethacin (10(-5) M) augmented the relaxation in all the groups of animals. The present study demonstrated that garlic and turmeric are potent vasorelaxants as well as reduce the atherogenic properties of cholesterol. Whether combination of these vasodilators in cardiovascular disorders with increased peripheral vascular resistance remains to be determined.

Influence of influenza viral infection on airway smooth muscle activity.

The contractility of airway smooth muscle (ASM) plays an important role in pathophysiology of several bronchial disorders. Increased contraction of ASM during asthma and respiratory viral infection has been attributed to the release of mediators acting through different receptors. In the present study, influence of influenza type A virus (H1N1) infection has been examined on ASM responsiveness to various bronchoactive agents e.g. adenosine, histamine, 5-hydroxytryptamine (5-HT) and isoproterenol in an organ bath set up for isolated tissue preparation. The contractile effect of adenosine, histamine and 5-HT was enhanced, however, relaxant response of isoproterenol was attenuated with the duration following viral exposure. The most prominent response was observed 48 to 72 hr after infection and tissues from multiple exposure to virus infected animals showed the maximum contractile response. Results demonstrated the deleterious effect of viral infection on ASM function and the findings will be helpful in understanding the mechanism of influenza virus induced bronchoconstriction.

Endothelium modulated vasorelaxant response of a polypharmaceutical herbal drug (lipotab) and its individual constituents.

The present study was undertaken to examine the endothelium modulated effects of polypharmaceutical drug lipotab and its individual ingredients in isolated aortic rings of rat. Endothelium intact and denuded aortic rings were precontracted with phenylephrine 10(-6) M and drugs were added in cumulative manner in concentration ranging from 1 to 50 microg/ml. The results demonstrated an endothelium-dependent vasorelaxant effect of lipotab and its individual ingredients, with the exception of nicotinic acid. The dose dependent relaxant response of nicotinic acid was not altered significantly in the endothelium-denuded rings, suggesting a direct effect of the drug on the vascular smooth muscle. Vasorelaxant effect of lipotab and its individual constituents suggests the therapeutic potential of these compounds in certain cardiovascular diseases.

Hypotensive effect of intracerebroventricular injection of norepinephrine and its modulation by alpha and beta adrenergic blockers in conscious rabbits.

The present study was designed to investigate the role of central adrenoceptors in the hypotensive effect of intracerebroventricular (ICV) injection of norepinephrine (NE) in conscious rabbits. Experiments were carried out on 19 adult rabbits (oryctolagus cuniculus) of either sex. A dose-dependent hypotensive response to ICV injection of NE was observed with no significant change in heart rate. The hypotensive response of NE was blocked 74.2 +/- 0.7% by yohimbine (alpha-2 adrenergic blocker), and 25.0 +/- 0.5% by metoprolol (beta-1 adrenergic blocker). NE response was not affected either by prazosin or butoxamine (alpha-1 and beta-2 adrenergic blockers respectively). The results suggest that the dose-dependent hypotensive response of ICV administered NE is mediated through alpha-2 and beta-1 central adrenoceptors.

Cardiovascular responses to phenylephrine during acute experimental anaemia in anaesthetized cats.

Experiments were performed on anaesthetized artificially ventilated cats to study the effects of phenylephrine (PE) on cardiovascular responsiveness, before and after induction of experimental anaemia. Acute anaemia was induced by replacement of blood by dextran in three steps of 20% each of total estimated blood volume. The effect of PE (20 micrograms/kg) was investigated at four stages: control and after 1st, 2nd and 3rd exchanges of blood. Induction of anaemia produced a significant increase in heart rate (HR) and cardiac output (CO) and a decrease in right atrial pressure (RAP). No significant change in mean arterial pressure (MAP), LV dP/dt max and blood gas tension was observed. Administration of bolus dose of PE produced a rapid rise in MAP, LVdP/dt max, and a decrease in HR without a change in the RAP. The pattern of response to PE was similar after induction of acute anaemia, however the magnitude of the response was significantly reduced. The attenuation in the response to PE was related to the fall in the haematocrit (HCT) level. This shows that induction of experimental anaemia, produced an increase in CO due to an increase in HR and SV and the effect of PE on cardiovascular responsiveness was significantly attenuated. The reduced sensitivity to PE during acute anaemia could be due to many factors such as inadequate O2 supply, effect of local vasodilating agents or some other cardiotonic agents which are known to contribute to vascular responsiveness.

Hemodilution-induced inhibition of cardiovascular responses to some vasoactive agents in anesthetized cats.

Cardiovascular responses to adrenaline and acetylcholine (ACh) were investigated in anesthetized, artificially ventilated cats in control and after induction of acute normovolemic hemodilution. Progressive replacement of blood by high molecular weight dextran was performed in three steps of 20% each of the total estimated blood volume. Hemodynamic responses were recorded at four stages: the control stage and after the 1st, 2nd, and 3rd exchanges of blood for dextran. With the fall in hematocrit (Ht) there was a corresponding significant (p < 0.05) increase in heart rate (HR), cardiac output (CO), and stroke volume (SV), and a decrease in systemic vascular resistance (TPR). However, left ventricular systolic pressure (LVSP), left ventricular contractility (LV dP/dtmax), mean arterial pressure (MAP), and right atrial pressure (RAP) did not show any significant (p > 0.05) change due to hemodilution. The cardiovascular responses of intravenously administered adrenaline and ACh were significantly (p < 0.05) attenuated. Responses to sodium nitroprusside (SNP), a potent vasodilator and an exogenous source of nitric oxide, were also attenuated after hemodilution. The increase in SV and HR seem to be the contributing factors to the CO response. Our results indicate that the cardiovascular responsiveness to adrenaline, ACh and SNP is reduced during acute hemodilution which could be due to inadequate myocardial and vascular O2 supply. The possibility of a modulatory role of an endothelium-dependent mechanism and reflex regulatory responses by arterial baroreceptors during hemodilution also exists.

Cardiovascular responses to phenylephrine and sodium nitroprusside during acute coronary occlusion in dogs.

The effects of administration of pressor agent phenylephrine (PE) and depressor agent, sodium nitroprusside (SNP) (10-40 micrograms/kg) on arterial blood pressure (ABP) and heart rate (HR) were investigated during acute occlusion of left anterior descending coronary artery (LAD) in anaesthetized, artificially ventilated dogs with and without the influence of selective blockade of autonomic nervous system (ANS). ABP response to PE was significantly (P < 0.05) attenuated following 4 hrs of LAD occlusion in all the four groups of animals. SNP response at higher dose (40 micrograms/kg) was also significantly (P < 0.05) attenuated 4 hrs after LAD occlusion in ANS intact, beta-blocked and atropinized groups. The bradycardia response to PE after LAD occlusion was abolished in vagotomized group while in the other three groups, it was significantly attenuated following 4 hrs of LAD occlusion. The tachycardia response to SNP was significantly (P < 0.05) attenuated 4 hrs after LAD occlusion in ANS intact and atropinized animals. The response was abolished in beta-blocked animals and no significant change occurred (P > 0.05) in vagotomized group. This study suggests that the cardiovascular reflex effects of PE and SNP are significantly attenuated following acute LAD occlusion. Blocking any of the components of ANS changed this responsiveness.

Concurrent abnormal expression of ERBB-2, EGFR, and p53 genes and clinical disease progression of breast carcinoma.

Metastatic phenotype in human solid tumors is believed to follow stochastic acquisition of structural genetic aberrations-so-called multistep tumor progression. We tested this hypothesis in breast carcinoma by immunostaining 89 stage-heterogeneous cases for the products of three genes (p53, ERBB-2, and EGFR) which are frequently altered in this tumor system. Variable relationships were observed between advanced disease stage and immunostaining for individual gene products (ERBB-2 - p = 0.05, EGFR - p = 0.02, p53 - p = 0.12, Chi Square test). Regional or distant metastases at presentation correlated with multiple oncogene/tumor suppressor gene expression abnormalities: node negative -59% none positive, 29% one positive, 12% two or more positive, vs. node positive -37% none positive, 23% one positive, 39% two or more positive (p = 0.01). Only 2/12 (17%) of tumors with distant metastases at presentation were negative for abnormal expression of any of these gene products, and 7/12 (58%) were positive for two or three. Among axillary node negative patients who developed recurrences, 67% exhibited staining for at least one gene product, compared to only 27% of those without recurrences (p = 0.02). All 5 cases with abnormal staining for each gene product had regional or distant metastases at presentation and recurred. In multivariate analysis, individual expression of p53 outweighed expression of ERBB-2 and EGFR in correlation with outcome. These data suggest clinical neoplastic progression of breast carcinomas correlates with cumulative genetic events detectable by protein expression. Short term recurrence, however, may correlate more closely with abnormal expression of p53 than with EGFR or ERBB-2.

Inhibition of arterial baroreceptor reflex during coronary artery occlusion.

The sensitivity of baroreceptor reflex during myocardial ischemia induced by acute occlusion of left anterior descending coronary artery (LAD) was studied in anesthetized, artificially ventilated, and thoracotomized dogs. Occlusion of LAD attenuated the baroreflex mediated changes in heart rate (HR) in response to changes in arterial pressure (AP) in the animals with intact autonomic nervous system (ANS). The HR increased significantly with the time of occlusion of LAD in control (ANS) as well as in beta-blocked group, suggesting vagal inhibition. In atropinized and vagotomized animals, the HR remained unchanged following LAD occlusion. In control group, the sensitivity of baroreflex mediated tachycardia response to hypotension and bradycardia response to hypertension, after 4 h of LAD occlusion, was reduced. In beta-blocked animals, the tachycardia response after LAD occlusion was drastically reduced to almost zero. The peak sensitivity of baroreflex bradycardia response was reduced in atropinized and vagotomized animals while the peak sensitivity of baroreflex tachycardia response increased after vagotomy. In contrast, bradycardia response was increased after beta-blockade. These data indicate that acute LAD occlusion attenuates arterial baroreflex control of HR and reduction of baroreflex sensitivity is mediated by parasympathetic efferents.