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Biomedical subjects

K K Singh

Publications and source records attributed to K K Singh.

At least 19 recordsLinked to original sources
PubMed1996

Distribution of time of first birth in presence of social customs regulating physical separation and coital frequency.

The interval between marriage and the first birth in India, particularly in rural areas, is much longer than what is observed in western countries. In eastern Uttar Pradesh, the mean interval is observed to be even longer, possibly due to traditional customs such as the female partner's visits to her parents in the early years of marriage and the smaller chance of coition because of the observance of rigid intercourse taboos. Thus the models to explain the length of the interval of marriage to first birth proposed by Western demographers, which assume that the period of cohabitation between marriage and first birth is uninterrupted, often do not describe the data satisfactorily when applied to rural India. In this paper a model to describe data on first birth interval is proposed that takes account of the distributions of timing and periods of physical separation and variation in fecundity with effective marriage duration.

Adolescent↗
PubMed1996

Effect of chronic fenvalerate (synthetic pyrethroid) intoxication on the immune response of goats to Brucella abortus strain 19 vaccine.

Fenvalerate, a widely used pesticide, was administered orally to goats at a dose rate of 15 mg/kg body weight, daily for 270 days. After 90 days of dosing, the animals, together with appropriate controls, were vaccinated with Brucella abortus strain 19. The fenvalerate reduced both the humoral and cell-mediated immune responses, as assessed by the standard tube agglutination test and delayed hypersensitivity test, respectively.

Animals↗
PubMed1996

Design of hammerhead ribozymes to distinguish single base changes in substrate RNA.

Hammerhead ribozymes are attractive tools in antisense gene inactivation because of their catalytic cleavage of target molecules. High sequence discrimination should be possible, since the cleavage efficiencies were already significantly reduced, if single base changes in substrate RNA introduce mismatches next to the cleavage site. This was observed at the first innermost base pair in helix I and the two innermost base pairs in helix III. In addition to its position, the nature of the mismatch pair was important.

Autoradiography↗
PubMed1995

Replication protein A binds to regulatory elements in yeast DNA repair and DNA metabolism genes.

Saccharomyces cerevisiae responds to DNA damage by arresting cell cycle progression (thereby preventing the replication and segregation of damaged chromosomes) and by inducing the expression of numerous genes, some of which are involved in DNA repair, DNA replication, and DNA metabolism. Induction of the S. cerevisiae 3-methyladenine DNA glycosylase repair gene (MAG) by DNA-damaging agents requires one upstream activating sequence (UAS) and two upstream repressing sequences (URS1 and URS2) in the MAG promoter. Sequences similar to the MAG URS elements are present in at least 11 other S. cerevisiae DNA repair and metabolism genes. Replication protein A (Rpa) is known as a single-stranded-DNA-binding protein that is involved in the initiation and elongation steps of DNA replication, nucleotide excision repair, and homologous recombination. We now show that the MAG URS1 and URS2 elements form similar double-stranded, sequence-specific, DNA-protein complexes and that both complexes contain Rpa. Moreover, Rpa appears to bind the MAG URS1-like elements found upstream of 11 other DNA repair and DNA metabolism genes. These results lead us to hypothesize that Rpa may be involved in the regulation of a number of DNA repair and DNA metabolism genes.

Base Sequence↗
PubMed1995

Presentation of endometriosis to general surgeons: a 10-year experience.

The presentation and management of 24 patients with endometriosis (median age 34 (range 21-68)years) presenting to general surgeons over a period of 10 years (1985-1994) was reviewed. Patients presented with an abdominal wall swelling related to a previous Pfannenstiel incision (seven patients), umbilical swelling (four), inguinal canal swelling (two), incidentally following appendicectomy (five), terminal ileal obstruction (two), rectal bleeding (two) and urinary symptoms (two). Endometriosis was not suspected in most patients but was confirmed by surgical excision or resection with minimal morbidity. No recurrence occurred during a median follow-up of 53 (range 9-113) months. Endometriosis is a disease rarely seen by general surgeons and is often diagnosed incidentally or on histological examination. Cyclical symptoms associated with menstruation are present in 50 per cent of patients and should suggest the diagnosis in those presenting with scar-related and/or subcutaneous swellings. Simple excision or resection of the presenting lesion provides adequate treatment but, since pelvic endometriosis may be present, referral to a gynaecologist is recommended in every case.

Abdominal Muscles↗
PubMed1995

Proximate determinants of fertility in eastern Uttar Pradesh.

Our main objective here is to examine and discuss the effects of some sociocultural and economic factors on the proximate determinants of fertility in rural areas of eastern Uttar Pradesh (population more than 40 million persons). The region is known for its present demographic trends because the crude birth, death, and infant mortality rates are among the highest for India. The determinants considered are age at marriage of female, postpartum amenorrhea (PPA), fecundability and sterility, and menopause. The sociocultural and economic factors studied are caste, education, breast-feeding status, and social status of the currently married females in the reproductive age group. The study population is predominantly Hindu, among whom caste is a strong indicator of socioeconomic conditions. The average age of the female at return marriage (RM) is below 18 years in each religion or caste group but has been increasing over time. Median durations of breast feeding and PPA differ significantly among various socioeconomic and demographic subgroups. These are longest in scheduled castes and shortest in upper-caste Hindus. As the social status of the household increases, the median durations of breast feeding and PPA decrease. The estimates of fecundability consistently decrease with age, whereas those of sterility increase with age after 35 years. The smallest estimate of sterility is 4%, corresponding to the 25-30-year age group in each religion or caste group. Occurrence of menopause is rare before age 35, and it increases with the age of the female irrespective of religion or caste. However, the risk is minimum for females in upper castes and maximum for those in scheduled castes.

Adolescent↗
PubMed1995

Ring enhancing CT lesions--a diagnostic dilemma.

We studied 68 such cases of RECTL with follow up ranging from 3 months to 3 years. Patients were divided into 3 groups depending on the size of ring ie. Group I (less than 5 mm), Group II (5-10 mm), Group III (10-20 mm). Maximum cases were in Group II (42), in the age group 20-40 years. 60 cases presented with seizures. Single ring was seen in 46 cases and multiple rings in remaining 22 cases. There were 22 cases of tuberculoma, 15 neurocysticercosis, 15 disappearing lesions, 4 malignancy, 2 abscess, 1 each showing infarction and gliosis and 8 of unknown etiology. Partial or total excision biopsy was done in 18 cases of which 3 were due to tuberculoma, 7 neurocysticercosis, 4 tumours, 2 abscess and 1 each due to infarction and gliosis. We found that RECTL could be a real diagnostic problem, which could be solved only be repeated clinical examination and CT Scan with excision biopsy in some selected cases.

Diagnosis, Differential↗
PubMed1994

The role of breast-feeding beyond postpartum amenorrhoea on the return of fertility in India: a life table and hazards model analysis.

This paper investigates the effects of continued breast-feeding after resumption of menses on fertility, using data from two retrospective surveys in India and single decrement life table and multivariate time-dependent hazards analyses. Breast-feeding even after the return of menses is found to be associated with longer birth intervals. The interaction of breast-feeding duration after resumption of menses and postpartum amenorrhoea has a significant effect on the risk of conception after return of menses.

Adult↗
PubMed1994

Botulinum toxin A in blepharospasm and hemifacial spasm.

We report the first Indian experience of botulinum toxin A in the treatment of blepharospasm and hemifacial spasm. Sixteen patients, 7 with essential blepharospasm, 5 with Meige syndrome and 4 with hemifacial spasm received botulinum toxin A injection. One patient received 3 courses of injections, 2 received 2 courses and the rest received only one course. The effect was observed after a latent period of less than 48 hours in all patients and lasted for a mean of 16.65 weeks. More than 70% improvement occurred after 17/20 injections (85%). Poor response was more often seen when blepharospasm was associated with oromandibular dystonia (2/5 injections). Though the duration of response and subjective score of improvement was best in patients with hemifacial spasm, the numbers were very small for any statistical evaluation. The side effects were local, transient, mild and well tolerated. The commonest side effect was blepharoptosis.

Adult↗
PubMed1993

Analysis of birth intervals in India's Uttar Pradesh and Kerala States.

Life tables of birth intervals and median birth intervals in two Indian states, Uttar Pradesh and Kerala, were computed for several subgroups of the study population. Multivariate hazards modelling technique was used to examine the net effect of each of the variables studied. The results show a substantial effect of socioeconomic variables in child-spacing after controlling for the major intermediate variables.

Adolescent↗
PubMed1993

A common element involved in transcriptional regulation of two DNA alkylation repair genes (MAG and MGT1) of Saccharomyces cerevisiae.

The Saccharomyces cerevisiae MAG gene encodes a 3-methyladenine DNA glycosylase that protects cells from killing by alkylating agents. MAG mRNA levels are induced not only by alkylating agents but also by DNA-damaging agents that do not produce alkylated DNA. We constructed a MAG-lacZ gene fusion to help identify the cis-acting promoter elements involved in regulating MAG expression. Deletion analysis defined the presence of one upstream activating sequence and one upstream repressing sequence (URS) and suggested the presence of a second URS. One of the MAG URS elements matches a decamer consensus sequence present in the promoters of 11 other S. cerevisiae DNA repair and metabolism genes, including the MGT1 gene, which encodes an O6-methylguanine DNA repair methyltransferase. Two proteins of 26 and 39 kDa bind specifically to the MAG and MGT1 URS elements. We suggest that the URS-binding proteins may play an important role in the coordinate regulation of these S. cerevisiae DNA repair genes.

Alkylation↗
PubMed1993

Age of marriage and length of the first birth interval in a traditional Indian society: life table and hazards model analysis.

The length of the first birth interval is one of the strongest and most persistent factors affecting fertility in noncontracepting populations, with longer intervals usually associated with lower fertility. Compared to Western society, the average length of the first birth interval is much longer in traditional Indian society. Yet Indian fertility rates are higher because of either ineffective family planning procedures or deliberate nonuse of birth control and because of the high proportion of the population that is married. Here, we examine the effects of various sociodemographic covariates (with an emphasis on the role of age at marriage) on the length of the first birth interval for two states of India: Assam and Uttar Pradesh. Life table and multivariate hazards modeling techniques are applied to the data. Covariates such as age at marriage, present age of mother, female's occupation, family income, and place of residence have strong effects on the variation of the length of the first birth interval. For each subgroup of females (classified according to different levels of the covariates), the median length of the first birth interval for the Assam (Bengali-speaking) sample is shorter than that of the Uttar Pradesh (Hindi-speaking) sample.

Adolescent↗
PubMed1993

Effects of breast feeding after resumption of menstruation on waiting time to next conception.

We investigate the association between breast feeding after resumption of menstruation and the duration from resumption of menses to the next conception. Data from a survey, "Breast-Feeding and Its Effect on Fertility," conducted in 1987 under the auspices of the Centre of Population Studies, Banaras Hindu University, India, were used. We used hazard models of conception rates after the return of menstruation with breast-feeding duration as a time-dependent covariate. The interaction of breast-feeding duration after resumption of menses and postpartum amenorrhea have a significant effect on the rate of conception after return of menses. After resumption of menstruation, when there is no breast feeding, the risk of conception increases with the increase in postpartum amenorrhea. However, breast feeding attenuates the effects of postpartum amenorrhea. These results suggest that breast feeding beyond the resumption of menstruation plays a significant role in the proximate determinants to reduce fertility.

Adult↗
PubMed1992

Interrogative suggestibility among adolescent boys and its relationship with intelligence, memory, and cognitive set.

This study investigates some of the hypotheses generated by the Gudjonsson and Clark model of interrogative suggestibility. The subjects were 40 adolescent boys (11-16 years), who completed the Gudjonsson Suggestibility Scale and instruments measuring intellectual skills, memory, field-dependence, hostility, and attitudes towards persons in authority. Suggestibility correlated negatively with I.Q. and memory capacity, and positively with field-dependence.

Adolescent↗
PubMed1992

Genetic nature of vitiligo.

Four hundred vitiligo patients and 100 non-vitiliginous controls were studied to find out the prevalence of vitiligo in relatives of patients and controls. The difference was found to be statistically highly significant. The data reflected that there is some genetic mechanism involved in the etiology of vitiligo. Respective relatives of all forms of the disease in the vitiligo group showed a clear preponderance compared to controls. There was clustering of affected relatives in vitiligo cases compared to controls. The ratio of affected and unaffected siblings with unaffected parents or one parent affected, the ratio in the children of probands, the ratio in children of affected paternal and maternal grandparents of probands, suggest the polygenic nature of vitiligo.

Adult↗
PubMed1992

Alternative topogenic signals in peroxisomal citrate synthase of Saccharomyces cerevisiae.

The tripeptide serine-lysine-leucine (SKL) occurs at the carboxyl terminus of many peroxisomal proteins and serves as a peroxisomal targeting signal. Saccharomyces cerevisiae has two isozymes of citrate synthase. The peroxisomal form, encoded by CIT2, terminates in SKL, while the mitochondrial form, encoded by CIT1, begins with an amino-terminal mitochondrial signal sequence and ends in SKN. We analyzed the importance of SKL as a topogenic signal for citrate synthase, using oleate to induce peroxisomes and density gradients to fractionate organelles. Our experiments revealed that SKL was necessary for directing citrate synthase to peroxisomes. C-terminal SKL was also sufficient to target a leaderless version of mitochondrial citrate synthase to peroxisomes. Deleting this tripeptide from the CIT2 protein caused peroxisomal citrate synthase to be missorted to mitochondria. These experiments suggest that the CIT2 protein contains a cryptic mitochondrial targeting signal.

Amino Acid Sequence↗