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Biomedical subjects

A Singh

Publications and source records attributed to A Singh.

At least 73 records · Page 4Linked to original sources
PubMed2004

Assessment of allergenicity to Mallotus phillipensis pollen in atopic patients in India: a new allergen.

OBJECTIVE: Pollen grains of the Euphorbiaceae family are well known causative agents of respiratory allergies in India, European countries and USA. Mallotus phillipensis belongs to the same family and may have some common allergenic properties. It has thus been evaluated for the first time in Indian population for its pollinosis causing properties. METHODS: Pollen antigen of Mallotus phillipensis (MP) was extracted and characterized for its protein components by biochemical methods. Pollinosis potency of crude extract of MP pollen was evaluated by skin prick test on population residing in different parts of India. Specific IgE binding characteristics of the extract were determined by ELISA and Immunoblot. RESULTS: Marked skin reactivity in 5.7% atopic population was recorded and subjects constituting 23.8% of the total patients tested showed skin sensitivity to the MP pollen antigen. Significantly raised specific IgE against MP pollen were recorded in 50% of the skin test positive patients. A number of protein bands were detected in a wide Molecular weight range as well as in acidic pI range, by SDS-PAGE and IEF, respectively. A total 11 protein fractions were detected by the specific IgE antibodies on immunoblotting with patient's sera and were considered allergenic. CONCLUSION: Patients from different geographical regions have shown sensitization to MP pollen antigen. Many proteins have similar molecular weights and pI as other allergenic members of the family (Ricinus communis and Putranjiva roxburghii) found in India, which constitutes a good reason for studying cross reactivity among the members of family Euphorbiaceae, in the future.

Allergens↗
PubMed2003

Suppression of third-order intermodulation in a klystron by third-order injection.

The first observations and measurements are reported on suppression of the third-order intermodulation (IM3) product arising from nonlinear mixing of two drive frequencies in a klystron, by externally injecting a wave at the IM3 product frequency. Optimum amplitude and phase of the injected wave for maximum suppression are examined. Results indicate that suppression of the IM3 product by as much as 30 dB can be achieved. Experimental results compare favorably with predictions of a 1D simulation code that takes into account all kinematical and dynamical effects including charge overtaking and space charge forces.

Journal Article↗
PubMed2003

Inhibition of IL-6+IL-6 soluble receptor-stimulated aromatase activity by the IL-6 antagonist, Sant 7, in breast tissue-derived fibroblasts.

Interleukin 6 (IL-6) and its soluble receptor (IL-6sR) can markedly stimulate aromatase activity in cultured fibroblasts derived from normal or malignant breast tissues. IL-6 acts by binding to a low-affinity membrane-spanning receptor (IL-6R), which must associate with a high-affinity receptor (gp130) for signal transduction to occur. Sant 7 is a mutated form of IL-6 that can bind to the IL-6R, but inhibits its ability to interact with the gp130 signal transducing protein. In this study, we have used Sant 7 to examine its ability to inhibit IL-6+IL-6 soluble receptor (IL-6sR)-stimulated aromatase activity in breast tissue-derived fibroblasts. As previously observed, IL-6+IL-6sR markedly stimulated aromatase activity (7.7-20.8-fold) in fibroblasts derived from reduction mammoplasty tissue, tissue proximal to tumours and breast tumours. Sant 7 inhibited basal aromatase activity in some fibroblasts by 25-30% that had a high basal activity, but almost completely blocked the ability of IL-6+IL-6sR to stimulate aromatase activity. The IC(50) for the inhibition of IL-6+IL-6sR-stimulated aromatase activity by Sant 7 was 60 ng ml(-1). A comparison of the effects of prostaglandin E(2) (PGE(2)), which can also regulate aromatase activity, and IL-6+IL-6sR revealed a greater degree of aromatase stimulation by IL-6+IL-6sR. Sant 7, however, inhibited PGE(2)-stimulated aromatase activity by 70% suggesting that PGE(2) acts, in part, by stimulating IL-6 production. Much of the IL-6 and IL-6sR available to stimulate breast tumour aromatase activity may originate from infiltrating macrophages and lymphocytes. The ability to block aromatase stimulation by these factors may offer a novel therapeutic strategy for reducing oestrogen synthesis in breast tumours.

Aromatase↗
PubMed2003

Earlobe reconstruction using a Limberg flap in six ears.

Many methods of earlobe reconstruction using one or two stages have been described. These have used (i) the superimposition of two flaps, (ii) a single flap lined with a skin graft or (iii) doubled-over single or bilobed flaps. We present a new method of earlobe reconstruction using a doubled-over Limberg flap, which we have used in six ears. This produces a good-looking earlobe, which needs defatting after 3-4 months and suffered minimal necrosis at the tip of the folded flap in three cases. There was no earlobe shrinkage on long-term follow-up.

Adolescent↗
PubMed2003

ENT presentations in children with HIV infection.

Illnesses of the ear, nose and throat (ENT) are common in children with human immunodeficiency virus (HIV) infection. We reviewed the case files of 107 HIV seropositive children in the paediatric HIV unit at St Mary's Hospital. The prevalence, age of onset and type of ENT disease were reviewed. We also determined sex distribution, maternal country of origin and mode of transmission of HIV. Fifty per cent of the HIV children had ENT illnesses. Fifty-five per cent of the children presented with their first ENT symptom before age 3 years with 98% of the children having ENT manifestations by age 9 years. The commonest ENT diseases were cervical lymphadenopathy (70%), otitis media (46%), oral candidiasis (35%) and adenotonsillar disease (31%). HIV transmission was vertical in 90%. Maternal country of origin was Africa in 70% and the UK in 13%. Compared with previous studies, the proportion of HIV children with ENT problems appears to have decreased. Although our figures report a similar ENT symptom profile, the age at onset of these symptoms has increased.

AIDS-Related Opportunistic Infections↗
PubMed2003

Spectrum of opportunistic infections in AIDS cases.

Human Immunodeficiency viruses are the initial causative agents in AIDS, but most of the morbidity and mortality in AIDS cases result from opportunistic infections, Identification of such pathogen is very important for clinicians and health planners to tackle the AIDS epidemic in more effective manner. The present study describes the clinical and laboratory profile of 100 AIDS causes who presented to a referral hospital. Oral candidiasis (59.00%) was found to be the most common opportunistic infection, followed by tuberculosis (56.00%), Cryptosporidium infection (47.00%) and Pneumocystis carinii (7.00%). Presence of oral candidiasis and weight loss is highly predictive of low DC4 count and can be considered as a marker of HIV disease progression. The patients coinfected with HIV and tuberculosis are also on rise. Recognition of dual infection and taking adequate steps to deal with this epidemic is needed. As Cryptosporidium infection was detected in large number, provision of safe drinking water and maintaining good hygiene is important for prevention. Early diagnosis of opportunistic infection and prompt treatment, delays the progression towards AIDS. 91.00% of patients were infected with HIV1 and 4.00% had HIV2 infection and 5.00% were dully infected. 87.00% of patients were males and 13.00% were belonging to 21-40 years of age. Majority of them were belonging to lower socioeconomic status and heterosexual route of transmission was the commonest mode of spread.

AIDS-Related Opportunistic Infections↗
PubMed2002

Enhanced transformation of polycyclic aromatic hydrocarbons using a combined Fenton's reagent, microbial treatment and surfactants.

The potential for using Fenton's reagent (H(2)O(2)+ Fe(2+)) as an advanced oxidation pretreatment process to enhance microbial transformation of two model polycyclic aromatic hydrocarbons, anthracene and benzo[a]pyrene, in an aqueous system was evaluated. Fenton's reagent at a concentration of 0.5% H(2)O(2) and 10 mM Fe(2+) (molar ratio, 15:1) was most effective in transforming anthracene at pH 4. Application of non-ionic surfactants during Fenton's pre-treatment was found to be more effective in the transformation of both anthracene and benzo[a]pyrene. The extent of removal of substrates by a combined Fenton's-biotreatment was 2-4 times higher than with Fenton's treatment or biotreatment alone. In a chemical-biological treatment train, 48 h of Fenton's pre-treatment in the presence of a non-ionic surfactant, followed by 7 days of biological treatment resulted in 80-85% removal of PAHs (100 ppm).

Anthracenes↗
PubMed2002

Biotechnology and bioremediation: successes and limitations.

With advances in biotechnology, bioremediation has become one of the most rapidly developing fields of environmental restoration, utilizing microorganisms to reduce the concentration and toxicity of various chemical pollutants, such as petroleum hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, phthalate esters, nitroaromatic compounds, industrial solvents, pesticides and metals. A number of bioremediation strategies have been developed to treat contaminated wastes and sites. Selecting the most appropriate strategy to treat a specific site can be guided by considering three basic principles: the amenability of the pollutant to biological transformation to less toxic products (biochemistry), the accessibility of the contaminant to microorganisms (bioavailability) and the opportunity for optimization of biological activity (bioactivity). Recent advances in the molecular genetics of biodegradation and studies on enzyme-tailoring and DNA-shuffling are discussed in this paper.

Biodegradation, Environmental↗
PubMed2002

Effect of heated and humidified carbon dioxide gas on core temperature and postoperative pain: a randomized trial.

BACKGROUND: Intraoperative hypothermia is a common event during laparoscopic operations. An external warming blanket has been shown to be effective in preventing hypothermia. It has now been proposed that using heated and humidified insufflation gas can prevent hypothermia and decrease postoperative pain. Therefore, we examined the extent of intraoperative hypothermia in patients undergoing laparoscopic Nissen fundoplication using an upper body warming blanket. We also attempted to determine whether using heated and humidified insufflation gas in addition to an external warming blanket would help to maintain intraoperative core temperature or decrease postoperative pain. METHODS: Twenty patients were randomized to receive either standard carbon dioxide (CO2) gas (control, n = 10) or heated and humidified gas (heated and humidified, n = 10). After the induction of anesthesia, an external warming blanket was placed on all patients in both groups. Intraoperative core temperature and intraabdominal temperature were measured at 15-min intervals. Postoperative pain intensity was assessed using a visual analogue pain scale, and the amount of analgesic consumption was recorded. Volume of gas delivered, number of lens-fogging episodes, intraoperative urine output, and hemodynamic data were also recorded. RESULTS: There was no significant difference between the two groups in age, length of operation, or volume of CO2 gas delivered. Compared with baseline value, mean core temperature increased by 0.4 degrees C in the heated and humidified group and by 0.3 degrees C in the control group at 1.5 h after surgical incision. Intraabdominal temperature increased by 0.2 degrees C in the heated and humidified group but decreased by 0.5 degrees C in the control group at 1.5 h after abdominal insufflation. There was no significant difference between the two groups in visual analog pain scale (5.4 +/- 1.6 control vs 4.5 +/- 2.8 heated and humidified), morphine consumed (27 +/- 26 mg control vs 32 +/- 19 mg heated and humidified), urine output, lens-fogging episodes, or hemodynamic parameters. CONCLUSION: Heated and humidified gas, when used in addition to an external warming blanket, minimized the reduction of intraabdominal temperature but did not alter core temperature or reduce postoperative pain.

Adult↗
PubMed2002

The use of PCR combined with restriction enzyme analysis to characterize fowl adenovirus field isolates from northern India.

Ten fowl adenoviruses (FAVs), isolated from suspected cases of inclusion body hepatitis (IBH) in quails and broilers, were characterized by a hexon-based polymerase chain reaction (PCR) combined with restriction enzyme analysis (REA) of the amplified DNA fragments. All the isolates could be detected using H1/H2 and H3/H4 primer sets. Amplification of DNA with H1/H2 and H3/H4 primer sets resulted in fragments of approximately 1219 bp and 1319 bp, respectively. HaeII digestion of the H1/ H2 PCR products and HpaII digestion of the H3/H4 PCR products characterized all the isolates in FAV groups, known from genomic typing using the whole DNA. For some of the isolates, neutralization tests were used to confirm these results. The results revealed that, as well as FAV serotype 1, which is the sole member of DNA group A, FAVs of DNA group E are also associated with IBH in poultry in northern India. The FAV specific PCR combined with REA was found to be very useful in investigating the epidemiological situation in the field. It was even possible to define mixed infections with more than one FAV.

Adenoviridae Infections↗