Nanocrystalline cubic CuFe2O4: size dependent transition from ferrimagnetic to superparamagnetic behaviour

Nanocrystalline cubic CuFe2O4 have been prepared by co-precipitation method. The experimental conditions have been controlled to produce CuFe2O4 with particle size 18 nm, 7.2 nm, and 3.2 nm as calculated by Scherrer formula. Room temperature Mössbauer spectra show that 18 nm and 7.2 nm CuFe2O4 exhibit ferrimagnetism while 3.2 nm CuFe2O4 exhibits superparamagnetism. The cationic distribution calculated using Mössbauer spectra confirm to the cubic structure confirming the findings of XRD study. XPS data corroborates the finding. Low temperature Mössbauer measurements on 3.2 nm particles show gradual transformation to ferrimagnetic state.

Alteration of serum copper in Kala-azar patients during SAG therapy

We conducted an analytic case-control study in Kala-azar patients during Sodium Antimony Gluconate (SAG) therapy to assess the changes in serum copper. A total of 89 subjects were included in the study. Diagnosed patients of Kala-azar with parasitological evidence of Leishmania Donovani (LD) bodies in bone marrow, were selected as cases (n=54). They were selected from Medicine and Paediatric wards of Mymensingh Medical College Hospital, Mymensingh and nearby Fulbaria upazila of Mymensingh district. Physically healthy volunteers of similar age, sex and body mass index (BMI) as cases, were included in control group (n=35). The study period was from July 2003 to June 2004. SAG was given intramuscularly (20 mg/kg/day) to Kala-azar patients for 30 days. Blood samples were collected from controls, Kala-azar cases before therapy and same cases during 15-20 days of SAG therapy. Serum copper was higher in cases before therapy than those of controls (p<0.001). However, serum copper reduced significantly (p<0.001) during SAG therapy. So biochemical monitoring may be considered in the management of the disease.

Isolated islets in diabetes research

This review highlights some recent developments and diversified applications of islets in diabetes research as they are rapidly emerging as a model system in biomedical and biotechnological research. Isolated islets have formed an effective in vitro model in antidiabetic drug development programme, screening of potential hypoglycaemic agents and for investigating their mechanisms of action. Yet another application of isolated islets could be to understand the mechanisms of beta cell death in vitro and to identify the sites of intervention for possible cytoprotection. Advances in immunoisolation and immunomodulation protocols have made xeno-transplantation feasible without immunosuppression thus increasing the availability of islets. Research in the areas of pancreatic and non pancreatic stem cells has given new hope to diabetic subjects to renew their islet cell mass for the possible cure of diabetes. Investigations of the factors leading to differentiation of pancreatic stem/progenitor cells would be of interest as they are likely to induce pancreatic regeneration in diabetics. Similarly search for the beta cell protective agents has a great future in preservation of residual beta cell mass left after diabetogenic insults. We have detailed various applications of islets in diabetes research in context of their current status, progress and future challenges and long term prospects for a cure.

Platelet activation, upregulation of CD11b/ CD18 expression on leukocytes and increase in circulating leukocyte-platelet aggregates in Indian women chronically exposed to biomass smoke

The majority of households in rural India still rely on unprocessed solid biomass for domestic energy. The aim of this study was to investigate whether chronic exposure to biomass smoke causes activation of leukocytes and the formation of leukocyte-platelet aggregates. We conducted flow cytometric analysis of beta2 Mac-1 integrin (CD11b/CD18) expression on polymorphonuclear leukocytes (PMN) and monocytes, and P-selectin (CD62P) expression on the platelets of 165 women from eastern India, who cook solely with wood, dung and agricultural wastes, and 155 age- and socio-economic condition-matched control subjects, who used relatively cleaner fuel, liquefied petroleum gas (LPG). Leukocyte-platelet aggregates were defined as CD11b-positive PMN and monocytes co-expressing platelet-specific markers CD41 or CD62P. A significant increase in leukocyte-platelet aggregates was found in women who used biomass as cooking fuel. In addition, they showed increased surface expression of CD11b/CD18 in circulating PMN and monocytes and CD62P expression on platelets. The mean fluorescence intensity (MFI) of CD11b on the surface of circulating monocytes and PMN of biomass users increased by 50 and 68%, respectively. Similarly, a 62 and 48% increase in MFI was observed in CD18 expression on the surface of these cells in biomass users. The results show that chronic biomass smoke exposure activates circulating platelets, PMN and monocytes, and increases the number of leukocyte-platelet aggregates, which are considered a risk factor for thrombosis.

Interaction of HIPPI with putative promoter sequence of caspase-1 in vitro and in vivo

To investigate the mechanism of increased expression of caspase-1 in Hippi expressing HeLa and Neuro 2A cells, reported earlier, we report here that HIPPI directly interacted with upstream sequence of caspase-1 gene (-700 to +17, 717 bp). Deletion of this 717 bp sequence and further analysis by electrophoretic mobility shift assay and fluorescence quenching revealed that HIPPI interacted with 60 bp (-151 to -92) upstream sequence of caspase-1. We also observed by chromatin immunoprecipitation assay that HIPPI interacted with the 717 bp sequence in vivo. In luciferase assay, when expression of the reporter gene was driven by either 717 bp or 60 bp caspase-1 upstream sequences, luciferase activity was increased in GFP-Hippi expressing HeLa cells in comparison to that obtained with parental HeLa cells with the same constructs. Similar result was obtained in Neuro2A cells with 717 bp caspase-1 upstream sequence. In summary, we showed that HIPPI could interact with the putative promoter sequence of caspase-1 and increased the expression of the downstream gene suggesting that HIPPI could act as transcription regulator.

Pregnancy as the prodrome to vascular dysfunction and cardiovascular risk

In previously apparently healthy women, glucose intolerance and high blood pressure during pregnancy are common and frequently occur together. This article reviews the role of these gestational disorders as markers of vascular dysfunction and its pathophysiology. Mechanisms include alterations to function of large arteries and resistance vessels and to capillary blood flow. Much of the vessel pathology is seen in both gestational diabetes and hypertension. In women who have had transient diabetes during pregnancy and later redeveloped overt diabetes, cardiovascular risk is already elevated nearly fourfold before diagnosis, which is almost as high as the average risk after a clinical diagnosis of diabetes is made. This key finding suggests that vascular risk in such women is at least partly independent of overt hyperglycemia.

A crypto-Dravidian origin for the nontribal communities of South India based on human leukocyte antigen class I diversity

The Dravidian communities are considered to be the original inhabitants of India, now restricted to South India. The southern most state, Kerala, is socio-culturally stratified into Hindus, Muslims and Christians on the basis of religion. The origin of these religious communities in Kerala is considered to be unique in comparison with that in other parts of the country. These communities were later influenced by the hierarchical caste structure established by the Hindu Brahmins. In the present study, we compared six nontribal (Namboothiri, Nair, Ezhava, Pulaya, Malabar Muslim and Syrian Christian) communities belonging to the major religious groups in Kerala (Hindu, Muslim and Christian) based on the human leukocyte antigen (HLA)-A, -B and -C diversity. Our aim was to understand the genomic substructuring associated with the changing social scenario in various caste and religious groups and compare it with the Dravidian tribal and other world populations. The present study reveals that the HLA diversity of the Dravidian communities is very distinct from that in the other world populations. It is obvious that the nontribal communities of Kerala display a greater Dravidian influence, but traces of genetic admixture with the Mediterranean, western European, central Asian and East Asian populations can be observed. This characterizes the crypto-Dravidian features of the nontribal communities of Kerala. Demic diffusion of the local progressive communities with the migrant communities may have given rise to crypto-Dravidian features among the nontribal communities of Kerala.

Galvanic deposition of nanocrystalline ZnO thin films from a ZnO-Zn(OH)(2) mixed phase precursor on p-Si substrate

A galvanic technique for the deposition of ZnO thin films is reported. The depositions were carried out on p-type single-crystal silicon substrates at room temperature, from a solution of ZnSO(4), where the Zn rod acted as a sacrificing anode and p-Si was the cathode. The deposition of ZnO by this method is pH sensitive, and a pH between 4 and 5 is found to be optimum for film deposition. This deposition technique is simple, inexpensive and can be carried out at room temperature. X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies revealed the nanocrystalline structure of the films. The resistivity of the annealed ZnO films was determined by the Van der Pauw measurement technique.

Vaccination status of tribal mothers and their under five children

A study was done to find out the vaccination status of the tribal mothers and their under 5 children in some selected villages of Durgapur upazila under Netrakona district. It was a cross sectional study in which 92 tribal mothers and 91 under 5 children were included. The study was carried out in 4 different tribal villages under Netrakona district from February to June 2001. According to National EPI schedule, it was revealed that 58.2% of the children were fully vaccinated, 26.4% incompletely and 15.4% not vaccinated. The individual vaccine coverage was 84.6% for BCG, 68.1% for OPV and DPT, 58.2% for Measles. Considering the literacy, most of the respondents (78.3%) were illiterate and 21.7% had some basic education. None of the mother completed 5 doses of TT coverage. The individual TT coverage was found 78.3% for TT(1), 67.4% for TT(2), 17.4% for TT(3) and 1.1% for TT(4). This study observed that the vaccination status in the tribal children was satisfactory in relation to National coverage, but the vaccination status of the tribal mothers was not satisfactory in our national context.

Deformation luminescence produced during application and release of pressure on to gamma-irradiated CaF2:RE crystals

Calcium fluoride CaF2 is an interesting host lattice for rare earth (RE) activators. CaF2 crystals doped with different concentrations of Dy, Ce, Er and Gd have been grown by the Bridgman technique and their deformation luminescence (DL) induced by room temperature gamma irradiation has been recorded. When a uniaxial pressure is applied on to gamma-irradiated CaF2:RE crystals, initially the DL intensity increases with time, attains a maximum value and then it decreases with time. Although the DL intensity produced during the release of pressure is less, its rise and decay behaviours are similar to that obtained during the application of pressure. The DL intensity depends on dopant, concentration of dopant, irradiation doses and mass of the load or applied pressure. It is suggested that the moving dislocation produced during deformation of crystals capture holes from hole trapped centres (like perturbed Vk centre) and the subsequent radiative recombination of the dislocation holes with electrons give rise to DL.

Diabetes and ethnic minorities

The global prevalence of diabetes for all age groups is estimated to be 2.8%. Type 2 diabetes accounts for at least 90% of diabetes worldwide. Diabetes incidence, prevalence, and disease progression varies by ethnic group. This review highlights unique aspects of the risk of developing diabetes, its overwhelming vascular complications, and their management mainly using data among South Asians and African-Caribbeans in the UK but also using non-UK data. It is concluded that although the origin of the ethnic differences in incidence need further clarification, many factors should be amenable to prevention and treatment in all ethnic groups worldwide.

Serum zinc status of rural women taking combined OC

This prospective case-control study was undertaken on 78 women between 15 to 45 years of age from rural area to see alteration of serum zinc due to oral contraceptive (OC) use. Of the subjects, 34 women was taken as controls having no history of taking any form of hormonal contraceptives neither during the time of selection nor during one-year period prior to the study. All of the women in the control group were advised to start consuming oral pill (Sukhi) for 3 consecutive cycles and at the 3(rd) month, 25 women were taken as cases on longitudinal basis. Another 44 women were randomly selected as cases on the basis of using combined oral contraceptives (Sukhi) for 4 months onwards. Subjects were classified as follows on the basis of duration of oral contraceptive use: Group I (n=34) -- controls, Group II (n=25) -- 3 months, Group III (n=17) -- 4 months -- 2 years and Group IV (n=27) -- >2 years. Finally, 103 samples of blood (34 from controls and 69 from oral contraceptives users) were collected for estimation of Serum Zinc (microg/dl) by Atomic Absorption Spectrometry using UNICAM - AA Spectrometer. MeanSD of Serum Zinc significantly reduced in all 3 contraceptive groups in comparison to controls (p<0.001). It was recommended to carry out further study including larger population from rural area to elucidate alteration in serum zinc and other trace elements to correlate with side effects caused by hormonal contraceptive so that attempt could be made to mitigate those.

Modulation of tumor induced angiogenesis in Ehrlich ascites tumor

In this study the enzyme glutaminase, purified from the ascites fluid of ovarian cancer patients, was analysed for its antiangiogenic activity. Intraperitoneal administration of this enzyme reduces the number of tumor directed capillaries in solid and ascites tumor bearing Swiss mice induced by transplantation of Ehrlich ascites cells. The enzyme has a critical role in regulating the secretion of vascular endothelial growth factor (VEGF) from tumor cell and in turn tumor growth. Glutamine analogue like 6-diazo, 5- oxo L-norleucine (DON) is also found to be effective in regulating vascular endothelial growth factor (VEGF) secretion from tumor cells in vitro. Treatment with enzyme reduced serum VEGF levels of the tumor induced animals. In vitro VEGF production by EAC cells was reduced in a concentration dependent manner in presence of glutamine analogue.

HLA-B and HLA-C alleles and haplotypes in the Dravidian tribal populations of southern India

The Dravidians are believed to be the earliest inhabitants of India. Their subsequent migration and admixture with invading racial groups has been of scientific interest for population geneticists. In the present study, seven highly endogamous and extremely isolated colonies of Dravidian tribal populations (n = 105) from Kerala in South India were analysed and compared with random non-tribal Dravidian (RND) samples (n = 78) of southern India using the polymerase chain reaction with sequence-specific primer method for HLA-B and HLA-C typing. The tribal group comprises Adiya, Kanikkar, Kattunaikka, Kuruma, Kurichiya, Malapandaram and Paniya, while the RND group includes Malayalam-speaking individuals from various non-tribal castes of Kerala selected randomly. Some of the most frequent HLA-B alleles in the RND population were similar to the North Indian population and included B*07, B*61 (B*40), B*44, B*51, B*35 and B*52. Although B*61 was the most frequent allele in our total study population, the frequency fluctuated in individual populations. HLA-Cw*14 was one of the most frequent alleles while HLA-Cw*17 was totally absent in all populations studied. The haplotype B*61-Cw*14 was present in all the study groups except in Kurichiya, and the haplotype B*51-Cw*14 was only absent in Kattunaikka. Phylogenetic tree and correspondence analysis indicate that all the Dravidian tribal communities group together as a separate cluster, while the RND group of individuals from South India lie close to the North Indian population. This suggests that the RND population of South India might have a crypto-Dravidian origin, while the smaller Dravidian tribal communities have a distinct Dravidian origin.

Effects of age on antibody affinity maturation

The elderly are more susceptible to infectious diseases. Mortality and morbidity from infections increase sharply over the age of 65 years. At the same time, the efficacy of vaccinations in the elderly is decreased. The elderly also have an increased incidence of cancer and inflammatory diseases. All the above indicate an age-related dysregulation of the immune system. Evidence suggests that the change in the humoral immune response with age is a qualitative rather than a quantitative one, i.e. it is the affinity and specificity of the antibody that changes, rather than the quantity of antibody produced. There are a number of possible causes of this failure, one of which is a defect in the mechanism of hypermutation of immunoglobulin genes. We have studied individual clonal responses within germinal centres of spleen and Peyer's patches in young and old patient groups. Our results indicate that there is no difference in the actual mechanism of hypermutation with age. There are, however, differences that are due either to a change in selection processes or to a change in the founder cells available for activation.

Phosphorylation of Pak1 by the p35/Cdk5 kinase affects neuronal morphology

The small GTPase Rac and its effectors, the Pak1 and p35/Cdk5 kinases, have been assigned important roles in regulating cytoskeletal dynamics in neurons. Our previous work revealed that the neuronal p35/Cdk5 kinase associates with Pak1 in a RacGTP-dependent manner, causing hyperphosphorylation and down-regulation of Pak1 kinase activity. We have now demonstrated direct phosphorylation of Pak1 on threonine 212 by the p35/Cdk5 kinase. In neuronal growth cones, Pak1 phosphorylated on Thr-212 localized to actin and tubulin-rich areas, suggesting a role in regulating growth cone dynamics. The expression of a non-phosphorylatable Pak1 mutant (Pak1A212) induced dramatic neurite disorganization. We also observed a strong association between p35/Cdk5 and the Pak1 C-terminal kinase domain. Overall, our data show that in neurons, membrane-associated, active Pak1 is regulated by the p35/Cdk5 kinase both by association and phosphorylation, which is essential for the proper regulation of the cytoskeleton during neurite outgrowth and remodeling.