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Biomedical subjects

K K Dubey

Publications and source records attributed to K K Dubey.

16 recordsLinked to original sources

Sexual behavior of drug-users: is it different?

BACKGROUND: Across the world, drug-users (DU) have been shown to be at greater risk of contracting and transmitting sexually transmitted diseases and HIV infection. However, in the metropolitan cities of India, where drug-use patterns may uniquely vary between injection and noninjection, depending on drug availability, little is known about the risk behavior of drug-users. OBJECTIVE: The objective of the study was to find out whether drug-users are more likely to practice high-risk sexual behavior compared to non-drug users. METHODS: The sexual behavior of 70 drug-users, selected by snowball sampling, was compared with 128 age- and economic status-matched controls (non-drug-users), randomly selected from the same community. RESULTS: Seventy-eight percent sexually active drug-users and 43% sexually active non-drug-users had multiple sex partners (P < 0.02). The average number of sex partners was significantly higher among the drug-users (P = 0.05). Anal intercourse was practiced by 25.7% drug-users and 8.6% non-drug-users (OR = 3.7; P < 0.01). The drug-users were 6.7 times more likely to visit commercial sex workers (P < 0.0001). Sexually transmitted disease prevalence was higher among the drug-users (P < 0.003). CONCLUSIONS: Notwithstanding the small sample size, this study shows that drug-users practice high-risk sexual behavior more frequently. Interventions, in the form of awareness generation and prevention education programs, are required in order to reduce risk of sexually transmitted diseases and HIV transmission among drug-users.

Adult↗

Synthesis and biological properties of DNA-sugar conjugates.

In order to improve the pharmacological properties of antisense and antigene oligonucleotides, oligodeoxynucleotides conjugated with amino sugars at the 5'-terminus were synthesized by solid phase fragment condensation (SPFC) method. The obtained DNA-sugar conjugates were evaluated in their chemical and biological activities to show that 5'-end modification of oligonucleotides with sugars enhanced the thermal stability of the hybrid duplex with complementary DNA, the resistance against nuclease digestion and the membrane permeability of the conjugates.

Amino Sugars↗

Synthesis and biological properties of DNA-peptide conjugates.

Some naturally occurring nuclear localizing signals (NLSs) and some artificially designed peptides were covalently conjugated by solid phase fragment condensation (SPFC) method. These DNA-peptide conjugates showed enhanced permeability into cells as well as enhanced hybrid stability with ssDNA and dsDNA, and also higher resistance against nuclease digestion.

Base Sequence↗

Design and synthesis of curcumin-bioconjugates to improve systemic delivery.

Di-O-glycinoyl curcumin (I), di-O-glycinoyl-C4-glycyl-curcumin (II), 5'-deoxy-5'-curcuminyl thymidine (5'-cur-T) (III) and 2'-deoxy-2'-curcuminyl uridine (2'-cur-U) (IV) have been synthesized and characeterised by elemental analysis & 1H NMR. The antibacterial activities of these four bioconjugates has been tested particularly for multiresistant micro-organisms. Best results are shown by I & IV. These bioconjugates serve dual purpose of systemic delivery as well as therapeutic agents against viral diseases.

Anti-Infective Agents↗

Psychosocial dysfunction in tuberculosis patients.

Tuberculosis continues to be a major health problem in India. It carries social stigma and results in adverse psychological sequelae. In the present study, 50 patients suffering from tuberculosis were examined. There was higher degree of neuroticism and the patients with tuberculosis showed marked to severe psychosocial dysfunctioning in personal, familial, vocational, social and cognitive areas.

Adolescent↗

A novel fluorescent tag for labelling of some antisense oligonucleotides.

A new versatile fluorescent tag, 4-acetylamino-1,8-naphthalimido-N-caproic acid (NCA) has been synthesized and characterized, and the optimal conditions for the maximum fluorescence using this tag allow a sensitivity level of 10(-9) mol/l. Useful fluorescence is observed upon covalent linking of this tag via its activated carboxy end to an alkylamino moiety, activated by the use of carbonyldiimidazole and hexamethylenediamine at the 5'-termini of an octamer, d(TCTTGCTC), a 33-mer, and a 41-mer complementary to the tat initiator of the HIV-1 genome. A new method for the generation of alkylamino function at the 5'-termini of oligonucleotides by the use of N-(4-bromobutyl) phthalimide is also described. The variation in fluorescence with respect to alteration of chain length of the oligonucleotides has also been studied. The fluorescence exhibited by these oligodeoxynucleotide (ODN)-NCA conjugates suggests that they may have a potential application as experimental tools in medicine and molecular biology.

Caproates↗

A novel strategy for O6-protection of guanosine.

A "one-pot reaction" has been used for simultaneous protection of amino and O6-function of deoxyguanosine. N-(4-bromobutyl) phthalimide used for O6-protection generates an alkylamino function after mild base hydrolysis. Two sequences d(GGA) and d(GGATCC) have been synthesised with all protected guanosine units. Similarly, 2-(vinyl)pyridine has also been used for O6-protection following the same strategy.

Base Sequence↗

Fluorophores for labeling of DNA/RNA fragments.

Three fluorescent tags, viz. 4-acetylamino-(N-caproyl)-1,8-naphthalimide, 4-acetylamino-(N-p-carboxyphenyl)-1,8-naphthalimide and 4-acetylamino-1,8-naphthalic anhydride have been synthesized starting from acenaphthene. These were characterized by chromatographic and spectroscopic studies and their relative fluorescence assessed under different conditions. An octamer d(TCTTGCTC) complementary to tat initiator of HIV-1, SK 102(+), a 33-mer and SK 19(+), a 41-mer complementary to a highly conserved region of HIV-1 genome were synthesized. 4-Acetylamino-(N-caproyl)-1, 8-naphthalimide was tagged via its carboxyl function to the 5'-end of these oligonucleotides by generating aliphatic amino function through the reaction of 5'-hydroxyl with carbonyldiimidazole and subsequently with hexamethylenediamine. The resultant labelled oligonucleotides were purified by HPLC on RPC C18 column and showed significant fluorescence.

Base Sequence↗

Breast feeding patterns in an urban resettlement colony of Delhi.

Studies on duration and patterns of breast feeding based on recall may lead to a bias about the exact feeding status. The present study was designed to overcome this bias using the 'current status analysis method'. Mothers of 650 infants from 0 to 12 months of age attending a Health Centre were interviewed about the current feeding patterns of the infants and other socioeconomic variables. Month-wise prevalence of feeding patterns was determined. It was observed that breast feeding was maintained at a high level (more than 90%) throughout infancy while exclusive breast feeding showed a rapid decline. At 1 month, 74% and at 4 months, 46% of infants were exclusively breast-fed. The median duration of exclusive breast feeding was 3.83 months. Mothers with lesser education and lower family income were more likely to exclusively breast feed (p < 0.05). The time interval between birth and first breast feed was 24-48 hours in most (48.9%) of the infants. Majority (76.9%) of the infants received pre-lacteal feeds. Hospital-born infants received their first feed earlier and were less likely to receive pre-lacteal feeds as compared to those born at home (p < 0.001). Thus, the practice of exclusive breast feeding has to be promoted amongst pregnant and lactating mothers by health personnel. Also knowledge regarding infant feeding has to be imparted in schools and colleges.

Breast Feeding↗