Quercetin: critical evaluation as an antileishmanial agent in vivo in hamsters using different vesicular delivery modes

Chemotherapy is still a major challenge for in vivo drug targeting to macrophages. Toxicity remains the major obstacle for the most potent drugs already known in the therapy of leishmaniasis. Thus, new drugs and new delivery systems are sought. By using different vesicular delivery modes e.g. liposomes, niosomes, microspheres and nanoparticles, attempts have been made to deliver an indigenous antileishmanial compound, quercetin, to treat experimental leishmaniasis in the hamster model so as to increase its efficacy as well as to reduce the toxicity. At equivalent quercetin concentration, the nanocapsulated quercetin was found to be the most potent in reducing the parasite burden in the spleen as well as in reducing hepatotoxcity and renaltoxicity compared to free drug or drug in other vesicular forms. An inverse relationship between the efficacy and the size of the vesicles was established. Such a drug vehicle formulation especially in the nanocapsulated form may be considered for clinical trials.

Apolipoprotein E gene polymorphism in cerebrovascular disease: a case-control study

The association between apolipoprotein E (apo E) polymorphism and stroke has been controversial. So far there are no studies reported on the polymorphism of apolipoprotein E in cerebrovascular diseases in the Asian Indians. A blinded case-control study was therefore undertaken and the apo E genotypes and lipid profile of a total of 120 subjects (63 stroke patients and 57 healthy controls) were done. The frequency distribution of apo E alleles and genotypes were assessed and their relation with the occurrence of stroke in Asian Indian subjects was determined. A significantly high frequency of apo epsilon4 allele (30%) was observed in the stroke patients than the controls (11%) (p < 0.005), and patients with epsilon4 allele had a fourfold higher odds to develop stroke OR (95%CI) 4.2 (1.8-10.1) (p < 0.005). On multivariate analysis, after adjusting for age, triglycerides and hypertension, the association of epsilon4 allele with stroke was found to be no longer statistically significant, OR (95%CI) 1.2 (0.4-4.5) (p = NS). On multiple logistic regression analysis age, OR (95%CI) 1.1 (1.1-1.2) (p < 0.001), and hypertension OR (95%CI) 15.1 (2.6-89.1) (p < 0.005) were found to be independent risk factors for development of stroke. This is the first report to have examined the association of apo E gene polymorphism with stroke in the Asian Indians. This study suggests that apo epsilon4 allele, triglycerides, age and hypertension are the predictors for stroke development.

Apolipoprotein C3 SstI polymorphism and triglyceride levels in Asian Indians

BACKGROUND

A close association between Sst I polymorphism in the 3' untranslated region of the apolipoproteinC3 (APOC3) gene and levels of plasma triglycerides (TG) had been reported by different investigators. Hypertriglyceridemia(HTG) is a known risk factor for coronary artery disease (CAD) in the context of Asian Indians. We conducted a study on the relationship between APOC3 SstI polymorphism (S1S1, S1S2 and S2S2 genotypes) and plasma TG levels in a group of 139 male healthy volunteers from Northern India.

METHODS

DNA samples were analyzed by polymerase chain reaction (PCR) followed by SstI digestion. Digested PCR products were run on 3% agarose gel and visualized by ethidium bromide staining.

RESULTS

Rare S2 allele was highly prevalent in our study population (0.313) as compared to the Caucasians (0.00-0.11). The genotypic distribution was in agreement with Hardy-Weinberg equilibrium. S2 allele was almost two times more prevalent in the HTG group (N = 34) as compared to NTG group (N = 105) (p = 0.001). Multiple logistic regression revealed S1S2 individuals had age-adjusted odds ratio of 2.43 (95%CI = 0.99-6.01, p = 0.054) and S2S2 had 9.9 (95%CI = 2.66-37.29, p = 0.0006) for developing HTG in comparison to S1S1 genotype.

CONCLUSIONS

Our study shows a significant association between rare S2 allele and HTG in Asian Indians.

Unusual complications of ballooned feeding tubes

Percutaneous Endoscopic Gastrostomy (PEG) and Feeding Jejunostomy (FJ) with a Foley catheter are well-established techniques for providing long-term nutritional support. Mechanical complications of these procedures are well recognised. We report two unusual complications of feeding tubes related to the balloon. Patient 1: A 23 years old female cerebral palsy patient had a PEG tube changed to a ballooned gastrostomy tube. Following this she developed abdominal cramps, vomiting and later on haematemesis. Contrast study showed migration of the balloon causing pyloric obstruction and a small prepyloric ulcer. Partially deflating the balloon and pulling it back to the original position corrected this. Patient 2: A 39 years old male cerebral palsy patient with a Foley catheter feeding jejunostomy developed obstructive symptoms within 48 hours of surgery. The balloon was deflated repeatedly without resolution. The catheter was impossible to withdraw and irrigate. Contrast instilled via the balloon channel demonstrated that the catheter was significantly stretched and the balloon was in terminal ileum. The balloon was fully deflated and easily withdrawn to be replaced with uninflated Foley catheter. Enteral feeding was easily reestablished. If a patient with a ballooned feeding tube develops intestinal symptoms balloon complications should be suspected. Contrast study through the feeding channel or balloon inflation channel is useful in diagnosing tube related complication. The threshold for imaging should be low, particularly in patients who are difficult to assess clinically.

Purification and characterization of a growth-regulating laccase from Pleurotus florida

Pleurotus florida produces two laccase enzymes (L1 and L2) within which L2 is associated with the vegetative growth of the fungus. In the present investigation the L2 has been purified to homogeneity and characterized. The molecular mass of the enzyme has been determined to be 73 kDa and 70 kDa by gel filtration chromatography and SDS-PAGE, respectively. The purified enzyme shows a pI value of 4.2. The optimum reaction temperature is 50 degrees C. Spectroscopic analysis reveals that L2 has two copper atoms, a type I copper and a type II copper. The Km and some other kinetic parameters of L2 has been determined.

Validation of an ELISA for the quantitation of human complement receptor 1

An ELISA was developed and validated for the quantitation of Complement Receptor 1 (CR1) in human plasma. The ELISA employed a monoclonal anti-CR1 antibody adsorbed onto microtiter plates to capture CR1 in human plasma. The captured CR1 was treated with a detecting antibody which had a different epitopic specificity for CR1. HRP conjugated anti IgG (secondary antibody) was used for quantitation. The standard curve covered a wide range from 10 pg to 800 pg. The inter- and intra-assay variation were found to be low and within the acceptable limits. Specificity and accuracy for the assay was established by ensuring negligible cross reactivity with other proteins and an excellent parallelism between the sample and standard curve. The samples were checked for loss of sCR1 levels through freeze/thaw cycles at different intervals of time stored at -70 degrees C.

Bacopasaponin C: critical evaluation of anti-leishmanial properties in various delivery modes

Bacopasaponin C, an indigenous glycoside, was isolated from Indian medicinal plant Bacopa monniera (b. brahmi) and was tested for antileishmanial properties both in free and in various delivery modes, e.g., niosomes, microspheres, and nanoparticles that are used now as alternatives to more commonly used liposomes. The different vesicles were prepared by published protocols. The percent intercalation of Bacopasaponin C in liposomes, niosomes, and micropspheres determined at its absorption maximal (lambda(max) = 238 nm, epsilon = 8.6 x 10(3) M(-1) x cm(-1)) was found to be 30; for nanoparticles it was 50. At equivalent dose of 1.75 mg/kg body weight, every third day for a total of 6 doses in 15 days, Bacopasaponin C in all the vesicular forms was found to be very active. An inverse linear relationship between the efficacy and the size of the vesicles was established. As analyzed from tissue histology, blood pathology, and specific tests related to normal liver and kidney functions, Bacopasaponin C in each of the four vesicular forms was found to be without any side effects. Thus, because of its indigenous origin and non-toxic nature, Bacopasaponin C could very well be considered for application in the clinic through these alternative delivery modes.

Selectivity of protein oxidative damage during aging in Drosophila melanogaster

The purpose of the present study was to determine whether oxidation of various proteins during the aging process occurs selectively or randomly, and whether the same proteins are damaged in different species. Protein oxidative damage to the proteins, present in the matrix of mitochondria in the flight muscles of Drosophila melanogaster and manifested as carbonyl modifications, was detected immunochemically with anti-dinitrophenyl-group antibodies. Aconitase was found to be the only protein in the mitochondrial matrix that exhibited an age-associated increase in carbonylation. The accrual of oxidative damage was accompanied by an approx. 50% loss in aconitase activity. An increase in ambient temperature, which elevates the rate of metabolism and shortens the life span of flies, caused an elevation in the amount of aconitase carbonylation and an accelerated loss in its activity. Exposure to 100% ambient oxygen showed that aconitase was highly susceptible to undergo oxidative damage and loss of activity under oxidative stress. Administration of fluoroacetate, a competitive inhibitor of aconitase activity, resulted in a dose-dependent decrease in the life span of the flies. Results of the present study demonstrate that protein oxidative damage during aging is a selective phenomenon, and might constitute a mechanism by which oxidative stress causes age-associated losses in specific biochemical functions.

Quercetin abrogates taxol-mediated signaling by inhibiting multiple kinases

Cell cycle block in G(2)/M initiates apoptosis, but the mechanism of this signaling cascade are largely unknown. The microtubule-perturbing agent Taxol has multiple effects on this signaling pathway and is a potent inducer of apoptosis. The specific pathways activated by low, clinically relevant concentrations of the drug are still largely unknown and are dependent on cell type and drug concentration. In this work, we have investigated why HeLa cells respond to Taxol by undergoing complete apoptosis, whereas MCF-7 cells remain in an intermediate phase with reduced death. Three phases were distinguished in these apoptotic pathways. The initial phase characterized by cellular detachment is followed by a second phase which includes the onset of apoptotic morphology, and p38 and Bcl-2 phosphorylation. These two phases are common to both cell lines. HeLa cells then proceed to the third and final execution phase, which culminates in death, whereas MCF-7 cells do not progress. Interestingly, the isoflavonoid Quercetin, a known general kinase inhibitor and an antioxidant, was able to prevent the onset of Taxol-induced cellular detachment and to protect from cell death. Moreover, it blocked Taxol-induced phosphorylation of p38 and Bcl-2, and prevented a Taxol-induced change in relative mobility of the apoptosis signal-regulating kinase 1 (Ask1). Our data elucidate the signaling pathways activated by Taxol at low clinically relevant concentrations.

Direct observation of release of cytochrome c from lipid-encapsulated protein by peroxide and superoxide: a possible mechanism for drug-induced apoptosis

Release of cytochrome c from inside lipid vesicles and from inside proteoliposomes formed by cytochrome c oxidase has been studied by spectrophotometric methods. The protein encapsulated inside vesicles did not form complex with sodium azide solution added externally. Both hydrogen peroxide and superoxide were found to cause release of cytochrome c from the lipid encapsulated protein, which was detected from the distinct spectral changes due to the formation of the azide complex of cytochrome c in the solution. Cytochrome c encapsulated inside proteoliposomes containing cytochrome c oxidase (CcO) did not release the cytochrome c during enzymatic turnover of CcO. The anticancer drug, doxorubicin, was found to inhibit the biochemical function of cytochrome c oxidase and release of cytochrome c was observed from the proteoliposome encapsulating the protein during the enzymatic turnover in the presence of doxorubicin. The results indicated that the inhibition of enzymatic activity by doxorubicin possibly leads to the formation of reactive oxygen species, which induce the release of cytochrome c from inside to outside of the membrane.

Standing orientation and behaviour of goats during short-haul road transportation

A field study was conducted to observe the standing orientation and behaviour among a group of meat type goats during transit by road. Randomly selected goats were observed from 10 runs (10 goats per run) carried out on the same road and the duration of each run was about 50min. Two observers stood on the deck of the truck and each noted the ongoing activities of five animals. The most frequent standing orientation adopted by goats was parallel to the truck's direction of travel (24.7+/-2.1min) followed by diagonal orientation (11.9+/-1.6min) and perpendicular orientation (9.1+/-1.4min) during the 50min road journey. The goats were not observed to orient themselves opposite to the truck's direction of travel. Although, the animals changed their orientation frequently, apparently to maintain balance, there was a clear bias against the perpendicular and diagonal orientations. Mean frequencies for the various behaviours were: bleating (1.3), jumping (0.7), pushing (0.9), fighting (0.7), falling (3.1), urination (0.5), defecation (0.3) and rumination (0.1). Jumping and bleating mostly occurred at the start of the journey.Virtually all fallings were associated with the driver's changing speed of vehicle by braking (43.4%), cornering (32.4%), speed bump (12.3%) and acceleration (11.9%). These falls, which hamper the well being of animals in transit and are also responsible for bruising which can be prevented by careful driving and by adjusting the speed of the vehicle gradually.

Liposomal antioxidants in combating ischemia-reperfusion injury in rat brain

Liposome-encapsulated antioxidants have been tested in vivo to prevent oxidative attack during cerebral ischemia and reperfusion. Oxidative stress is a causal factor in the neuropathogenesis of ischemic-reperfusion injury. From the therapeutic point of view free chemical antioxidants were almost ineffective to protect cerebral tissues from those oxidative attacks. Thus an attempt has been made to prevent the oxidative damage due to the cerebral ischemic insult by the introduction of chemical antioxidants, ascorbic acid and alpha-tocopherol either encapsulated or intercalated in small unilamellar liposomes. The effectiveness of antioxidant-loaded liposomes was tested against an experimental in vivo rat model of global cerebral ischemia. Oxidative free radical attack on cerebral tissues by the ischemic insult and brief reperfusion was accounted for by the amount of diene production per unit of tissue protein. Diene production in ischemic reperfused rat brain increases almost twofold over that of the normal rats. Prevention of excess diene production has been attributed to rats when they were treated either with L-ascorbic acid-encapsulated liposomes or alpha-tocopherol intercalated liposomes 2 hours prior to the cerebral ischemic insult. Complete restriction of excess diene generation has also been achieved when a mixture of alpha-tocopherol and L-ascorbic acid-encapsulated liposomes were injected 3 hours before the ischemic infraction.

The handling and short-haul road transportation of spent buffaloes in relation to bruising and animal welfare

The handling of 100 spent buffaloes during transportation by truck from an animal market to a slaughterhouse was observed so as to assess the influence of sex, body condition (weak, normal or heavy), body size based on the height at the hump (small, medium or large) and handling method (dragging, dragging + hitting or lifting + hitting) on the manpower requirement and the time spent in both loading and unloading. A buffalo could be loaded onto a truck with the help of 2.8 labourers in 66 s, whereas the average manpower and time needed for unloading a buffalo were 1.9 labourers and 26 s, respectively. Sex and size had no significant effect on the manpower requirement or the time spent in loading and unloading. Animals in normal body condition needed more (p<0.05) manpower (3.2 labourers) for loading compared to weak animals (2.5 labourers) or heavy animals (2.6 labourers). The manpower and time required for loading and unloading were least (p<0.05) when a stick was used while dragging. Excessive steepness of the loading ramp caused some of the animals to fall down during loading, whereas a slippery truck floor, due to increased eliminative activities by nervous animals, might result in buffaloes going down during unloading. The mean number of bruises was 2.44 per head. As muscle tissues were involved in about 90% of the bruises, considerable economic losses occurred through bruising, which necessitated removal of damaged tissues post mortem. Most of the bruises were found on the hind limbs (43.4%), followed by the abdomen and udder region (21.3%), shoulder, neck and back (16.0%) and perianal region (11.1%).

Use of complement receptor 1 (CD35) assay in the diagnosis and prognosis of immune complex mediated glomerulopathies

Complement Receptor 1 (CR1) is a polymorphic glycoprotein expressed on erythrocytes, leukocytes and glomerular podocytes and has a major role in immune complex processing. In addition, it regulates the complement cascade activation by preventing formation of classical and alternative pathway convertases and by acting as a cofactor for Factor I mediated cleavage of C3. In this study, we have examined the expression of erythrocyte CR1 (E-CR1) and glomerular CR1 (G-CR1) in different kinds of nephropathies using ELISA and immunofluorescence microscopy to understand their role in immune complex (IC) mediated renal diseases. E-CR1 was significantly reduced in all categories of lupus nephritis in comparison to normal subjects and non-IC renal diseases. However, other IC mediated diseases like IgA nephropathy and membranoproliferative glomerulonephritis had normal E-CR1 levels. G-CR1 showed distinct differences between IC and non-IC mediated diseases. G-CR1 was virtually absent in lupus kidneys. In other IC mediated diseases, there was a correlation of G-CR1 expression to the IC and complement fragment deposition. G-CR1 serves as a useful diagnostic marker for IC mediated diseases while E-CR1 is useful as a prognostic marker to monitor the course of disease after the treatment has initiated.

Prescribing practices of consultants at Karachi, Pakistan

OBJECTIVE

To audit the prescribing practices of consultants.

DESIGN

A randomized sample survey of 354 consultants prescription for analysis of some basic parameters as recommended by World Health Organization (WHO).

MAIN OUTCOME MEASURES

To provide feedback to the prescribers for promoting rational drug therapy.

RESULTS

The average number of drugs for prescription were found to be 4.51 and the average daily cost of prescribed drugs was Rs: 133.41. The antimicrobials, vitamins/minerals and injections were over-prescribed. About half of the prescribed drugs were from the National Essential Drugs List of Pakistan (NEDLP) and only a little over 12% were prescribed by their generic names.

CONCLUSIONS

The prescribing practices of the consultants in Karachi are rather liberal and not rational. Overuse of antimicrobials and injections have been observed and there is general tendency of indulging in polypharmacy requiring continued medical education.

Plastination of whole brain specimen and brain slices

BACKGROUND

The human dead body specimens are plastinated for teaching purposes in medical institutions, using silicone. The silicone impregnated whole brain specimens and brain slices do not give satisfactory results.

METHODS

In the present study the brain specimens were plastinated with another polymer known as Polyester-Copolymer. The brain specimens were first preserved and then fixed with 5% formalin. The specimens were then dehydrated and degreased in a volatile solvent acetone. The specimens were placed in Polyester-Copolymer solution which penetrated the brain tissue both intracellulary and intercelluraly. The specimens were then cured by gas method.

RESULTS

The whole brain specimens and brain slices plastinated with Polyester-Copolymer were dry, odorless, handy and durable. It also gives a clear visual contrast between grey and white matter in brain slices whereas the brain specimens plastinated with silicone are flexible and sticky. There was no color contrast between grey and white matter.

CONCLUSION

The polyester impregnated brain specimens and slices are non-toxic and ideal for teaching purposes and examinations. They require minimal aftercare. The whole organ serial sections of plastinated brain specimens will help 3-dimensional study of the normal brain and will improve the assessment of brain pathology.

Targeting of liposomal andrographolide to L. donovani-infected macrophages in vivo

Despite the rapid development in medicinal and pharmaceutical technology, the targeting of drugs to phagocytic cells in macrophage-related diseases still remains a major unsolved problem. By using the mannosyl-fucosyl receptors on macrophages, attempts were made to target antileishmanial drugs encapsulated in mannosylated or fucosylated liposomes to treat experimental leishmaniasis in the hamster model. Mannosylated liposomes were found to be more potent in delivering antileishmanial drugs to phagocytic cells. Liposomes loaded with an indigenous drug, andrographolide, a labdane diterpenoid isolated from Indian medicinal plant Andrographis paniculata, were prepared and tested against experimental leishmaniasis in a hamster model. Mannosylated liposomes loaded with the drug were found to be most potent in reducing the parasitic burden in the spleen as well as in reducing the hepatic and renal toxicity. In addition, mannosylated drug-loaded liposome-treated animals showed a normal blood picture and splenic tissue histoarchitecture when compared with those treated with free drug or regular liposomal drug. Such a drug-vehicle formulation may be considered for clinical trials.

Accumulation of a natural substrate of laccase in gills of Pleurotus florida during sporulation

During sporulation, laccase activity of Pleurotus florida decreased to a minimum level in spite of increase in the number of isozymes. An endogenous laccase substrate was detected especially in the gill structure of the sporophore, which competitively inhibited oxidation of guaiacol by the enzyme during in vitro assay. Appearance of the laccase substrate in the gill structure may be linked with the sporulation phenomenon.

Expression of complement regulatory proteins in diffuse proliferative glomerulonephritis

This study assessed the expression of complement receptor 1 (CR1), decay accelerating factor (DAF) and membrane inhibitor of reactive lysis (CD59) on the erythrocytes and glomerulus of diffuse proliferative glomerulonephritis (DPGN) of systemic lupus erythematosus (SLE) patients using flow cytometry and immunofluorescence techniques to elucidate their role in the pathogenesis of DPGN. Expression of CR1 on the erythrocytes and glomerulus of DPGN patients was reduced compared with expression in normal subjects. However, expression of DAF and CD59 was increased on both erythrocytes and glomerulus of DPGN patients, suggesting the generation of a protective response against complement-mediated injury.

Purification and characterization of laccase-1 from Pleurotus florida

Pleurotus florida (ITCC 3308) produces two laccase enzymes (L1 and L2) in potato-dextrose media containing 0.5% yeast extract. Concentrated culture filtrate was separated on DEAE-Sephadex (A-50) column into two enzyme peaks, subsequently named L1 and L2. The L1 enzyme has been purified to homogeneity by ion-exchange and gel-permeation chromatography. L1 is a monomeric glycoprotein with a molar mass of 77 and 82 kDa as determined by SDS-PAGE and gel-filtration chromatography, respectively. The pI value of L1 has been determined to be 4.1. The optimum reaction temperature of the enzyme is 50 degrees C. The Km and some other kinetic parameters of L1 have been determined. Cyanide and azide completely inhibit the enzyme activity. The enzyme was fully active in 1:1 (V/V) buffer-chloroform for at least 2 h. Spectroscopic analysis revealed that the enzyme has four copper atoms, a type 1 copper, a type 2 copper and a type 3 binuclear copper.

ras gene mutations in oral cancer in eastern India

Oral tumor specimens (n = 50) from eastern Indian population were studied for the presence of mutations in the H-, K- and N-ras genes using selective oligodeoxynucleotide hybridization and restriction fragment length polymorphism analysis of polymerase chain reaction-amplified products. Mutations in H- and K-ras genes were observed at a frequency of 28 and 33%, respectively, whereas no N-ras mutation was noticed.

Effect of angiotensin II on liposome uptake by the rat brain in vivo

Studies have been performed to assess the possibility of using small unilamellar liposomes as therapeutic carriers to the brain of hypertensive rats. Rats were made temporal hypertensive by the infusion of angiotensin II (AII; 15 micrograms in 1 ml) through their right common carotid artery. Another control group was infused with physiological saline. Free 125iodine-BSA (125I-BSA) and 125I-BSA encapsulated liposomes (average diameter approximately equal to 100 nm) were injected in the tail vein 2 min after the infusion of AII or saline. Plasma radioactivity was monitored at different times up to 15 min when the cerebral uptake of 125I-BSA was determined. While a little variation in plasma clearance pattern of liposomes in hypertensive and control group was noticed, the uptake by cerebral tissues was markedly higher in hypertensive group. Analysis of pharmacokinetic parameters in relation to cerebral uptake indicated AII induced a short term opening of the blood-brain barrier (BBB) resulting in an increased cerebral uptake. Positively charged liposomes was found to be most effective in hypertensive state.

Effect of oxidative stress and erythropoietin on cytoskeletal protein and lipid organization in human erythrocytes

Phenylhydrazine (PHX)-mediated damage in human red blood cells has been assessed by monitoring the release of tyrosine from cell proteins as well as using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). PHX-treated red blood cells exhibited concentration- and time-dependent tyrosine release. ATP has no effect on the release of tyrosine. This observation is supported by SDS-PAGE pattern of RBC membrane proteins, which shows a correlation between tyrosine release and cytoskeletal protein degradation. PHX requires the presence of erythrocyte cytosolic fraction for the degradation, possibly due to the presence of a proteolytic enzyme in the cytosol. PHX treatment renders the membrane proteins susceptible to the proteolytic attack. Treatment of PHX-exposed erythrocyte with bee venom phospholipase A2 induces the translocation of phosphatidylserine (PS) and phosphatidylethanolamine (PE) to the outer surface of the cell membrane. At the same time, phosphatidylcholine (PC) was translocated towards the inner surface, altering the membrane phospholipid asymmetry. Interestingly, increased tyrosine production followed by translocation of phospholipids across the red blood cell membrane by PHX treatment is completely inhibited by 0.2 units of erythropoietin (EP). Our findings suggest that exposure of red blood cells to an oxidant like PHX causes degradation of cytoskeletal protein by an ATP-independent proteolytic pathway and this in turn allows the transbilayer movement of phospholipids across the cell membrane. EP, by scavenging the hydroxyl radicals produced during interaction of PHX with red blood cells, protects the erythrocytes from oxidative attack.

Differences in the platelet proaggregatory activity of immune complexes isolated from patients with myocardial infarction or pulmonary cancer

Immune complexes were isolated immediately after the onset of the symptoms of myocardial infarction on an anti-Clq affinity column. The platelet proaggregatory effects of these immune complexes were compared with those isolated from patients suffering from pulmonary cancer. A markedly increased proaggregatory effect of immune complexes derived from patients with myocardial infarction and changes in the sensitivity of platelets from healthy volunteers to PGI(2) (prostacyclin) and PGD(2) were found. In contrast, immune complexes from patients with pulmonary cancer did not show any significant effect. The antigenic part of immune complexes is probably relevant in the induction of platelet aggregation.

The estimation of the heritability of anthropometric measurements

The relative contributions of genetic and environmental components in the variability of anthropometric measurements were studied in 54 twin pairs. Thirty pairs of monozygotic (MZ) and 24 pairs of dizygotic (DZ) twins were investigated to estimate the role of genetic, environmental and hereditary factors determining anthropometric measurements comprising body weight, standing height, sitting height, knee height, arm span, chest circumference and biiliac diameter. Within-pair variance for all the measurements were significantly smaller (p < 0.05-0.01) in MZ twins than in DZ twins of both-sex twin group. Within-pair correlations for those measurements were higher (p < 0.01) in both MZ and DZ twins. Correlation values were, apparently, higher more in MZ than in DZ twins. Besides, all the measurements are highly heritable components and heritability estimates ranged 40%-91%. When both MZ and DZ twin pairs of both-sex population were classified, based on age and sex, into different sub-groups interindividual variabilities were altered to a certain degrees. These data state that anthropometric measurements are influenced by genetic factors than environmental factors and besides, age and sex are possibly associated, to some extent, with the genetic influence upon anthropometric measurements.

Problem based learning as a curricular strategy for medical undergraduates: a tutor's experience

This article focuses on the experiences and role of a tutor while conducting a problem based learning (PBL) exercise to facilitate the learning of biochemistry and molecular biology. A case presentation of sickle cell anemia was used to frame a module. The objective of this experimental exercise was to assess the suitability and effectiveness of problem based learning in the first year of undergraduate medical course and to practice self-assessment by tutors in this new role of a facilitator of learning through small group discussion. A tutor during such a learning session encouraged the students to apply their reasoning to analyze the problem and to develop self-directed learning skills in acquiring the knowledge appropriate to their perceived needs to work on a problem. The tutors ensured that they apply this knowledge in their work with other similar problems that they would encounter later in life.

Histidine decarboxylase gene in the mouse uterus is regulated by progesterone and correlates with uterine differentiation for blastocyst implantation

Cell-cell interactions between the blastocyst trophectoderm and uterine luminal epithelium are essential to the process of implantation. The factors that participate in these interactions or their mechanism of actions are poorly understood. Histamine has long been suspected as one of the factors that is involved in implantation. Histamine is formed from L-histidine by histidine decarboxylase (HDC). We examined the expression and regulation of HDC gene in the mouse uterus during early pregnancy and under steroid hormonal stimulation. Northern blot hybridization detected a 2.6-kb transcript of HDC messenger RNA (mRNA) in uterine poly(A)+ RNA samples. Maximum uterine accumulation of HDC mRNA occurred on days 3 and 4 of pregnancy, followed by marked declines on later days (days 5-8). In ovariectomized mice, uterine mRNA levels were up-regulated by an injection of progesterone (P4) by 6 h, and the levels were maintained through 24 h. In contrast, an injection of estradiol-17beta neither stimulated nor antagonized P4-induced HDC mRNA accumulation. P4-induced up-regulation was considerably abrogated by pretreatment with RU-486, a P4 receptor antagonist, suggesting involvement of P4 receptor. In situ hybridization detected HDC mRNA specifically in uterine epithelial cells but not in other cell types. Again, high epithelial accumulation occurred on day 4 of pregnancy. With the progression of implantation (days 5-8), HDC mRNA levels declined in the luminal epithelium surrounding the implanting blastocysts, as compared with that away from the blastocysts. Immunoreactive histamine and HDC were colocalized with HDC mRNA. Western blotting detected a 54-kDa protein in epithelial cell extracts, which also exhibited HDC activity. Expression of HDC in epithelial cells, preceding implantation on day 4, at lower levels after initiation of implantation on day 5, and its regulation by P4 suggest that this gene plays an important role in implantation.

Report of a hitherto unreported sequence present and expressed in a cancer cell line

During the amplification of a 202 base pair (bp) fragment around the 61st codon of the N-ras gene, an extra band of about 150 bp in length was observed when genomic DNA from a human epidermoid carcinoma cell line was used as template. This fragment was cloned and sequenced. However, this sequence was not found in the databank. RT-PCR experiments indicated that the sequence is expressed in the cells about 8 h after serum induction. The relevant RNA hybridized to one strand of the sequence but not to the other.

Immobilization of urease from pigeonpea (Cajanus cajan L.) in polyacrylamide gels and calcium alginate beads

Urease from pigeonpea was entrapped in polyacrylamide gel with 50% immobilization at 10% total monomer (containing 5% cross-linker) with high mechanical stability of the gel. Approximately 0.61 mg of protein could be loaded per 5 ml of gel. The immobilized enzyme had a t1/2 of approx. 200 days when stored in 0.1 M Tris/acetate buffer, pH 6.5, at 4 degrees C. The gel strips were used 4-5 times for urea assay over a period of 6 h with less than 2% loss of activity. Approximately 50% immobilization of urease in calcium alginate was observed at 3% alginate with 0.12 mg protein/ml alginate. The resultant enzyme beads showed a t1/2 of approx. 75 days when stored in 0.1 M Tris/acetate buffer, pH 6.5, at 4 degrees C. The beads were used 4-5 times for urea assay over a period of 6 h with about 40% loss of activity. In both cases, the enzyme activity was directly proportional to the amount of immobilized enzyme. There was practically no leaching of the entrapped enzyme over a period of 48 h from either of the polymers. Both the immobilized enzyme preparations were used to analyse the blood urea of some clinical samples from the University hospital. The results obtained compared favourably with those obtained by the usual method employed in the clinical pathology laboratory.

Biochemical and histopathological changes in respiratory system of rats following exposure to diesel exhaust

Effect of exposure to diesel exhaust (DE) for different durations was evaluated using histopathological and biochemical parameters in respiratory system of the rats. Animals were exposed to 1 part DE diluted with 5 parts of clean air in a simulation chamber for 15 min/day for 1, 7, 14 and 21 days. After completion of various exposures, biochemical parameters including elastase inhibitory capacity (EIC) and protein content of the bronchial airway lavage (BAL) and histopathological changes along with lung/body weight ratio were assessed. The elastase inhibitory capacity (an index of the protection against destruction of elastin, a lung connective tissue) was maximum at 1 week indicating thereby that the body renders protection against injury by increasing EIC levels in the initial phase. However, protein content in the BALF increased after 1 week and reached maximum at 2 weeks. Histopathological changes followed similar time course of pattern with accumulation of macrophages and protein exudation. Prolonged exposure up to 3 weeks, however was accompanied by chronic inflammatory changes and thickening of alveolar septa and blood vessels. Changes in lung/body weight ratio and suspended particulate matter (SPM) deposited on filters (simulation chamber) correlated well with EIC, protein content in BALF and histopathological changes. The biochemical findings accompanied with chronic structural changes in the lungs of rats following exposure to DE could be relevant to the clinical observation of increased incidence of chronic lung diseases after continued DE exposure.

Expression of betacellulin and epiregulin genes in the mouse uterus temporally by the blastocyst solely at the site of its apposition is coincident with the "window" of implantation

In the mouse, the process of implantation is initiated by the attachment reaction between the blastocyst trophectoderm and uterine luminal epithelium that occurs at 2200-2300 h on day 4 (day 1 = vaginal plug) of pregnancy. Several members of the EGF family are considered important in embryo-uterine interactions during implantation. This investigation demonstrates that the expression of two additions to the family, betacellulin and epiregulin, are exquisitely restricted to the mouse uterine luminal epithelium and underlying stroma adjacent to the implanting blastocyst. These genes are not expressed during progesterone-maintained delayed implantation, but are rapidly switched on in the uterus surrounding the implanting blastocyst following termination of the delay by estrogen. These results provide evidence that expression of betacellulin and epiregulin in the uterus requires the presence of an active blastocyst and suggest an involvement of these growth factors in the process of implantation.

Cerebral calcium fluxes and calcium homeostasis in the rat: a minimal model

Disturbance of calcium homeostasis and unregulated increase in intracellular calcium have been implicated in cell damage and cell death in the central nervous system in particular. To determine the specific pathway(s) of cerebral Ca transport of importance in a pathophysiological situation, we have measured long term Ca flux in brain in vivo in rat, and developed a kinetic model incorporating physiologically relevant pathways of cerebral Ca transport. 45Ca was injected into a tail vein in conscious rats. Plasma 45Ca was monitored up to 4 days post-injection and 45Ca uptake determined in samples of cerebrospinal fluid (CSF) and at several sites of brain at euthanasia. Uptake of the tracer by tissues peaked after 1 h, isotopic equilibration taking longer. The uptake at hippocampus was the highest. Computer simulation of the kinetics of the plasma, CSF and tissue data was performed using a compartmental model, which included two subcompartments (intra- and extra-cellular) and two pathways from plasma to the brain: directly across the blood-brain barrier and via CSF, which included a delay. The analysis based on this model enabled estimation of the fractional rates of transport of Ca to cerebral and noncerebral tissues across all the barriers of the model.

Problem based module for the learning of biochemistry and molecular biology of hepatitis

A problem based module for learning the concepts and practice of biochemistry and molecular biology in the understanding of hepatitis is suggested. The components of this module are (a) triggers--which represent case presentation, investigations and management strategies in the form of small statements organized in a logical sequence to provoke hypothetico-deductive reasoning and self directed identification of learning needs by the students, (b) guidelines for student tutor interaction--for conducting the learning exercise which is in the form of small group discussions facilitated by a tutor, (c) list of learning needs-essentially to be indentified in each group, (d) list of learning objectives--to ensure the necessary learning achievement, (e) few suggestions and guidelines for learning resources and (f) an overview of the problem. This module can be modified or altered for students at different phases of the medical curriculum. The suggested module can be best implemented through 3 tutorial sessions of 2 hours each, on alternate days, supported by 2-3 resource sessions (brief interactive/didactic lectures on selected difficult areas) in between. Alternate days can be organized for practical or skill sessions along with time for student's own learning and presentation in group during the tutorial session to be held on the following day.

Involvement of renin-angiotensin system in hypertensive effect of cadmium in rats

Role of renin-angiotensin system in hypertension induced by cadmium chloride (CdCl2) in rats has been investigated. Intravenous administration of CdCl (1 mg/kg) produced a biphasic response i.e. a transient fall followed by a marked and consistent rise in blood pressure. The peak hypertensive effect was accompanied by raised PRA levels. Pretreatment with captopril (1 mg/kg, i.v.) losartan (1 mg/kg, i.v.) or captopril + losartan attenuated the pressor response to Cd by 62%, 42% and 100% respectively in separate groups. Central administration of Cd (10 micrograms/rat, i.c.v.) showed a biphasic response similar to that observed after i.v. route. However, it was not accompanied by raised PRA levels. Prior treatment with losartan (10 micrograms/rat, i.c.v.) completely abolished the pressor response to Cd (i.c.v.) whereas it was not affected significantly by captopril (10 micrograms/rat, i.c.v.). On the other hand, centrally administered losartan only partially reduced the pressor response to i.v. Cd. The results are discussed in light of a differential involvement of central vs peripheral renin-angiotensin system in the hypertensive effect of Cd.

Uterine preparation for implantation in the mouse is associated with coordinate expression of estrogen-responsive finger protein and estrogen receptor

Estrogen-responsive finger protein (Efp) is a member of the RING finger-containing proteins. It is a putative transcription regulator that is speculated to amplify estrogen actions in the target organs. The present study examined the temporal and cell-type specific expression of Efp mRNA in the periimplantation mouse uterus (days 1-8) by Northern and in situ hybridization. Consistent with previous observation, a 6.0-kb transcript was detected in uterine RNA samples. The steady-state levels of Efp mRNA in whole uterine RNAs exhibited modest fluctuations during the periimplantation period. However, results of in situ hybridization showed cell-specific distribution of Efp mRNA in the periimplantation uterus in a temporal manner. On days 1-2 of pregnancy, distinct autoradiographic signals for Efp mRNA were detected in uterine luminal and glandular epithelia. However, on days 3 and 4, the accumulation of Efp mRNA occurred in stromal cells, in addition to its presence in the epithelium. After initiation of implantation on day 5, signal intensity was higher in stromal cells immediately surrounding the implantation chamber. However, on days 6-8, Efp mRNA was localized throughout the deciduum. To determine whether ovarian steroids influence the uterine expression of this gene, cell-specific localization of Efp mRNA was examined in the adult ovariectomized mouse uterus at 12 hr and 24 hr after an injection of estradiol-17 beta (E2) or progesterone (P4). An injection of E2 caused a modest increase in Efp mRNA levels in the luminal and glandular epithelia, while stromal cell accumulation occurred after an injection of P4. These results suggest that Efp is involved in P4/E2-mediated uterine cellular proliferation and/or differentiation. Since previous studies showed that Efp is colocalized with estrogen receptor (ER) in target cells, we also examined the cell-specific nuclear localization of ER in the periimplantation mouse uterus by immunohistochemistry. On days 1-2 of pregnancy, nuclear staining was distinct in the luminal epithelium and glandular epithelium. In contrast, nuclear staining was noted in stromal cells on days 3-4. However, glandular epithelium showed distinct staining during this period. On day 5, stromal cells surrounding the lumen at the mesometrial site were ER-positive. On days 6-8, the intensity of nuclear staining was very low, and limited to the cells adjacent to the luminal epithelium. The coordinate expression of Efp and ER in specific uterine cells during the preimplantation period (days 1-4) was consistent with the absolute requirement for estrogen in the preparation of the uterus for implantation. Since the amount of estrogen required for the preparation of the uterus is minuscule as compared to that of P4, these results suggest that the coexpression of Efp with ER is involved in amplifying the estrogen effects required for uterine cell proliferation and/or differentiation during implantation. In contrast, discoordinate expression of Efp and ER during the postimplantation period (days 5-8) suggests primary dependence of the decidualization process on P4, but not estrogen.

Relationship of national highway with injecting drug abuse and HIV in rural Manipur, India

Earlier study reported that about 1% of general population or urban Manipur was injecting drug users (IDUs). A study was conducted to observe the IDU prevalence in rural Manipur and the role of national highway (NH) in determining the IDU prevalence if any. It was also aimed to study the HIV prevalence among IDUs of different villages. Villages were startified in to 3 categories based on distance and communication facilities from the national highway, which cuts across the villages to the neighboring state, Nagaland. Villages close to NH had the highest IDU prevalence of 1.3% and remote villages had the least prevalence of 0.2% whereas villages in between the above mentioned two groups had a prevalence of 0.9%. It was surprisingly observed that HIV was uniformly distributed among the IDUs of all villages and ranged from 50-51%. This indicates that IDU prevalence at distance is predominantly determined by the presence of drug trafficking route/s like national highway whereas HIV prevalence is mainly determined by the needle sharing behaviour of IDUs.

Modulation of cerebral calcium homeostasis in rats by angiotensin II in vivo

The uptake of 45Ca2+ by different regions of the brain was determined in anaesthetised rat after infusing angiotensin II (AII; 14 micrograms in 1 ml) through the carotid artery. The control animals (C) were infused with physiological saline. 45Ca2+ was injected in the tail vein 2 min after the infusion of AII or saline. Plasma radioactivity was monitored until euthanasia at different times post injection when the cerebral uptake of 45Ca2+ was determined. While the plasma turnover of 45Ca2+ was similar in AII and C animals, the uptake was markedly higher in AII vs. C at the different brain sites at all times. Kinetic analysis suggested that AII induced a short term increase in Ca2+ transport across the blood-brain barrier and also in the cellular uptake. The effect of AII was receptor mediated being abolished by saralasin, an AII antagonist, and appeared to be at least in part independent of its pressor effect.

Cadmium induced nephrotoxicity in rats

Onset of hypertension and nephropathy after 1,2, and 4 weeks of exposure to cadmium chloride (1 mg/kg, ip) was studied in rats by measuring changes in blood pressure and renal function (urinary output, electrolytes, serum creatinine, inulin clearance and Na+K+ ATPase). Significant decrease in body weight and rise in blood pressure were observed as early as one week of exposure while microalbuminuria was detected in 50% of the animals after 2 weeks. Na+K+ ATPase, a renal tubular enzyme, was depressed after 1 week with maximum lowering occurring after 4 weeks. There were no detectable changes in fluid intake, urine output, electrolytes, inulin clearance and serum creatinine even after 4 weeks. It is concluded that hypertension and tubular lesion set in earlier than glomerulopathy as indicated by microalbuminuria and the latter could be the consequence of rise in blood pressure.

The effect of age on calcium dynamics in rat brain in vivo

Different biochemical changes accompany development and ageing. However, the time frame for a particular biochemical change may be different than that for another. In the ageing brain, neurological deficits related to ageing have been suggested to be due to a breakdown of calcium (Ca++) homeostasis, and an increase in intracellular Ca+2. To understand the dynamics of calcium in CNS in relation to normal ageing, we have determined 45Ca++ uptake by the different regions of brain in young (3 months) and aged (15 months) rats after a single i.v. injection of 90 microCi/kg 45Ca++. In the a-ed group, the initial plasma contents of the tracer were higher than in the young rats (3 months). The mean values of uptake (as fraction of injected dose/g x 10(5)) of 45Ca at different sites were higher in the 15-month-old animals than in the young rats (viz. cortex: 50 vs. 26; hippocampus: 90 vs. 46 and putamen: 54 vs. 30 at 120 min). Computer simulation of the uptake data indicated that the values of most of the fractional transport rates were similar or lower in the aged compared to the controls. However, the steady state ratio of intra/extracellular Ca++ was higher in the 15-month-old animals, suggestive of intracellular accumulation of Ca++.

Molecular cloning and sequence analysis of a seed-expressed acyl carrier protein (ACP) gene from Brassica campestris (Agrani)

We describe here the nucleotide sequence of the Brassica campestris ACPSF1 gene which encodes a seed-expressed acyl carrier protein (ACP). The 3600 bp sequence consists of 1740 bp upstream of the translation start codon, 828 bp spanning the coding region which is interrupted by three introns and 1032 bp downstream of the stop codon. Using a ACPSF1 gene-specific probe, transcripts could be detected in developing seeds, but not in leaves. The gene is now the only known member that represents group I seed-expressed ACP multigene family of Brassica species. The 5' flanking sequence of the ACPSF1 gene was examined for putative transcriptional regulatory elements. A sequence alignment of the 5' flanking regions of the available seed-expressed ACP genes of Brassica species showed some conserved regions which might have some common regulatory significance.

Lung function in Indian twin children: comparison of genetic versus environmental influence

The relative contributions of genetic and environmental components in the variability of lung function measurements were studied in 54 twin pairs. Thirty pairs of monozygote (MZ) twins and 24 pairs of dizygotic (DZ) twins were examined. All measurements were made with 9-litre closed-circuit-type expirographs using standard spirometric techniques, except for peak expiratory flow rate (PFER) which was recorded with a Wright peak flow meter. Within-pair variances for inspiratory capacity (IC), vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced mid-expiratory flow (FEV25-75%), forced end-expiratory flow (FEF75-85%), maximum expiratory flow (FEF200-1200ml), forced maximum voluntary ventilation MVVF) and PEFR were significantly smaller (p < 0.01) in MZ twins than in DZ twins. Tidal volume (VT), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), forced expiratory volume in 1 second as a percentage of forced vital capacity (FEV1%), and forced expiratory time (FET) were not significantly different. Within-pair correlations were all higher in MZ than DZ twins. All measurements except for VT and PEFR showed high levels of heritability (23-99%). All measurements were positively and significantly correlated with physical characteristics such as weight, standing height, surface area, arm-span, chest circumference and age, except FEV1% and FET. Residual values adjusted for physical characteristics showed similar results to unadjusted values in most cases. These data indicate that major lung function measurements are possibly influenced more by genetic than environmental factors. Genetically influenced measurements show higher levels of heritability estimates and suggest that genetic determination of lung function is possibly independent of the influence of physical characteristics.