Biomedical subjects
S Zaman
Publications and source records attributed to S Zaman.
An unusual cause of peripheral neuropathy.
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[Essential aspects of differential diagnosis of coronarogenic and non-coronarogenic myocardial lesions].
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Dephosphorylation of threonine 169 of Cdc28 is not required for exit from mitosis but may be necessary for start in Saccharomyces cerevisiae.
Entry into mitosis requires activation of cdc2 kinase brought on by its association with cyclin B, phosphorylation of the conserved threonine (Thr-167 in Schizosaccharomyces pombe) in the T loop, and dephosphorylation of the tyrosine residue at position 15. Exit from mitosis, on the other hand, is induced by inactivation of cdc2 activity via cyclin destruction. It has been suggested that in addition to cyclin degradation, dephosphorylation of Thr-167 may also be required for exit from the M phase. Here we show that Saccharomyces cerevisiae cells expressing cdc28-E169 (a CDC28 allele in which the equivalent threonine, Thr-169, has been replaced by glutamic acid) are able to degrade mitotic cyclin Clb2, inactivate the Cdc28/Clb2 kinase, and disassemble the anaphase spindles, suggesting that they exit mitosis normally. The cdc28-E169 allele is active with respect to its mitotic functions, since it complements the mitosis-defective cdc28-1N allele. Whereas replacement of Thr-169 with serine affects neither Start nor the mitotic activity of Cdc28, replacement with glutamic acid or alanine renders Cdc28 inactive for Start-related functions. Coimmunoprecipitation experiments show that although Cdc28-E169 associates with mitotic cyclin Clb2, it fails to associate with the G1 cyclin Cln2. Thus, an unmodified threonine at position 169 in Cdc28 is important for interaction with G1 cyclins. We propose that in S. cerevisiae, dephosphorylation of Thr-169 is not required for exit from mitosis but may be necessary for commitment to the subsequent division cycle.
Dental development, dental age and tooth counts. A prospective longitudinal study of Pakistani children.
A sample of 443 Pakistani infants from four different socioeconomic areas was followed longitudinally study the emergence of the primary teeth. The mean ages of emergence of the primary teeth, without regard what kind of tooth and dental ages of the primary teeth were calculated. The subjects showed no sexual dimorphism in the emergence times of the primary teeth. The children from poor areas. were ahead by statistically significant differences from upper middle class, for emergence of the primary teeth 17-20. On comparison with Swedish standards (Hägg & Taranger, 1985) Pakistani children are delayed, by a statistically significant difference, in the emergence of primary teeth 1-16, however, they were at par in the emergence of 17-20 primary teeth.
Studies on the antimicrobial activity of honey.
Ten samples of crude and processed honey were used to determine antimicrobial activity against twenty five species of pathogenic and nonpathogenic bacteria, commonly encountered in human infections. The antifungal activity was checked against ten parasitic and saprophytic fungi. Most of the samples of honey used in the study showed broad spectrum antibacterial and promising antifungal activity.
Practical epidemiology and biostatistics in research. Study design and statistics.
Soundly planned study may well lead to the findings that are of wide scientific application and interest. This paper is intended to provide a simple and systematic guideline pertinent to the design, analysis and interpretation of studies, especially in the health care. It emphases on the importance of 'Statistics' in the design, conduct, analysis and interpretation of the studies. It is pointed out that all the stages of research studies are vulnerable to statistical mismanagement. The most important thing is to balance the interests of the individuals in the study with those of the much larger number who may benefit in the long run. Concerning the proper use of statistics, the following things are recommended. (a) Statistical advice is needed at the planning stage of a project and not at its end; (b) statistical advice may be saught at almost every stage of a project; (c) the important aspects of logic and correctness of argument may be carefully looked before interpreting the results and (d) finally, before getting any work published, opinion of an expert statistician must be saught, so that erroneous conclusions may not become enshrined as the truth.
Primary hepatocellular carcinoma and viral hepatitis B and C infection in Bangladeshi subjects.
Potential risk factors for the development of primary hepatocellular carcinoma and the prevalence and role of infection with viral hepatitis B and hepatitis C were investigated in 54 adult patients of Bangladeshi origin (45 male, age range 20-75 years), comprising 46 patients resident in Bangladesh (Group 1) and 8 patients who had emigrated to the UK 10-20 years previously (Group 2). Of the 46 patients in Group 1 (37 male), 16 had hepatocellular carcinoma, 10 had uncomplicated cirrhosis, and 20 had a clinical history of chronic viral hepatitis of more than 6 months' duration. Total hepatitis B virus marker positivity was 82.6%, significantly higher than in Group 2 patients (P < 0.001). Thirty-six per cent were hepatitis B surface antigen positive, 66% were hepatitis Be antigen positive and 45.3% were positive for hepatitis C virus antibody. Taking only the 16 patients with hepatocellular carcinoma, hepatitis B surface antigen positivity was 38%, hepatitis Be antigen 66% and positivity to hepatitis C virus antibody was 56%. The 8 patients with hepatocellular carcinoma in Group 2 were all male and aged between 45 and 56 years. Of these, 3 (38%) cases were positive for hepatitis B surface antibody and none was positive for hepatitis B surface antigen or antibody to hepatitis C virus (3 cases tested). Presenting features of HCC in the two groups differed with a short clinical history of tender abdominal mass in Group 1 and a gradual onset of jaundice in Group 2 UK-resident Bangladeshi subjects.
Breast feeding is a natural contraceptive and prevents disease and death in infants, linking infant mortality and birth rates.
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Timing of emergence of individual primary teeth. A prospective longitudinal study of Pakistani children.
Primary tooth emergence in Pakistani children was investigated as a part of a prospective interdisciplinary study of growth and development. The average order of emergence of the primary teeth was in agreement with previous studies from other countries. There was no sex difference in emergence of individual primary teeth. The emergence of the primary incisors and mandibular first molars in both sexes, and the canines in boys were significantly delayed compared to Swedish standards (Hägg & Taranger 1986).
Multiplicity, structure, and function in GABAA receptors.
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Identification of the minimal replicon of the streptomycete plasmid pIJ101.
The minimal replicon of pIJ101 was defined to a 2.0-kb BalI-SacII fragment containing the rep ORF and a non-coding region of DNA, but not orf56 (pQR435). This non-coding region of DNA was found to be crucial for plasmid replication in Streptomyces lividans and may contain either the origin of replication or the rep promoter (or both). A 1.4-kb NotI-SacII fragment containing only the rep ORF produced a 54-kDa protein in vitro when expressed from the lacZ promoter. pQR435 was structurally unstable in S. lividans and accumulated single-stranded (ss)DNA. The insertion of the site for second-strand initiation (ssi) into pQR435 did not prevent the plasmid from rearranging or from accumulating ssDNA.
Liver transplantation for primary hepatocellular carcinoma: tumor size and number determine outcome.
Liver transplantation for primary hepatocellular carcinoma (HCC) has in general been complicated by high recurrence rates. In the present study results from experience of 87 patients were analyzed [56 cirrhotic, 31 non-cirrhotic, 6 with the fibrolamellar (FL) variant] in relation to curative potential. Sixty-two survived > 90 days and form the study cohort. Fifty-six had non-fibrolamellar HCC and, of these, 39 had discrete lesions, measuring 0.8-21 cm (median 5.0 cm) including 4 in whom the diagnosis was made after examination of the explanted liver; 23 had multifocal lesions (> 2 tumor masses). There was no tumor recurrence in the group of 14 cases with single dominant lesions measuring < 4 cm, whereas in the 15 cases with lesions of 4-8 cm the recurrence rate was 40%, and 78% in those > 8 cm and the multifocal lesions (n = 27, P = 0.0001). Five-year actuarial survival figures were 57.1%, 44.4% and 11.1% (P < 0.003) respectively. The mean survival times in patients who died of recurrence were: 4-8 cm, 3.3 years (range 10 months to 6.3 years); > 8 cm or multifocal, 13 months (3-25 months). Reduction of serum alpha-fetoprotein (AFP) to normal levels does not exclude a later recurrence (7 of 17 cases) and this was documented after maintenance of normal AFP levels for up to 29 months.(ABSTRACT TRUNCATED AT 250 WORDS)
Analysis of the site for second-strand initiation during replication of the Streptomyces plasmid pIJ101.
The indigenous plasmid pIJ101 is the parent of many cloning vectors used in Streptomyces. One early pIJ101 derivative, pIJ702, has been particularly widely used. pIJ702 lacks sti:cop/korB and accumulates single-stranded DNA (ssDNA). The 1.2 kb BclI-BclI sti:cop/korB and 0.7 kb SpeI-BclI sti regions were isolated from pIJ101 and cloned into pIJ702 at the PstI site in both orientations. No ssDNA was detected in constructs containing sti present in its correct orientation with respect to the basic replicon, with or without cop/korB. Constructs which contained sti in the reverse orientation did accumulate ssDNA. Thus, sti is only active as the site for second-strand synthesis in its natural orientation. Furthermore, sti inserted in either orientation into the structurally unstable pIJ702-pUC8 shuttle vectors prevented them from rearranging in S. lividans. The sti function was defined to a 0.53 kb SpeI-SacII fragment and the probable site for second-strand initiation (ssi) was identified.
Early child health in Lahore, Pakistan: I. Study design.
In this paper, details are given of a community based follow up study of four areas: a village, a periurban slum, an urban slum and an upper middle class control group living in and around Lahore, Pakistan. The aim was to characterize the determinants of child health in a rapidly urbanizing community. The study was undertaken in two steps. An initial cross-sectional survey collecting socio-economic and demographic background information was carried out between March to August 1984. This was followed by a longitudinal study of 1476 infants representing the outcome of the pregnancies registered continuously between September 1984 to March 1987 among the 3242 families in the study. These infants were followed monthly from birth to 3 years of age and thereafter less frequently. In this communication we describe the study design, the study population, the organization and the research methodology used, including the reasons for drop outs from birth to 24 months of age. The internal consistency of the data is also presented. After the initial examination of the newborns within between 0-7 days of birth, the infants were visited monthly for 24 months making a total of 20911 examinations. At 24 months of age 70% of the infants were still in the study, 11% had died before reaching this age, 13% had moved from the area and 6% had refused to participate in the study. The economic, conditions, social structure, and the quality of life were found, not surprisingly, to vary significantly among the four areas. This community-based project provides new, critical and reliable information for local health planners. The study highlights the importance of the development of a useful model for research collaboration between institutions in developed and developing countries.
Early child health in Lahore, Pakistan: IV. Child care practices.
Child care practices and hygiene measures were studied at 6 months of age in a longitudinally followed cohort of 1476 infants born between September 1984 to March 1987 in four socio-economically different areas in and around Lahore, Pakistan. Although, 76-98% of the mothers looked after their infants during health and 96-98% during a diarrhoeal illness, child care practices and hygiene measures differed significantly between the four areas. During a diarrhoeal episode, the mothers from the upper middle class took timely medical help, fed ample food and Oral Rehydration Salts (ORS) to the sick infants and provided uncontaminated food to them in clean surroundings. The mothers from the village and the periurban slum took their sick child, mostly after the second day of illness, to a doctor, but preferred home remedies. Fourteen percent of the mothers in the village and 6% in the periurban slum did not seek any medical help at all. One-third of the families, from these two areas, fed food to children 12 hours after cooking; the surroundings of the child were dirty with large numbers of flies present throughout the year, though the food was commonly kept covered with a lid. We constructed a simple measure of the surroundings of the child, rated as dirty, medium or clean; it was found to be associated to both parental illiteracy and child growth, but not with housing standard. The main conclusion is that any attempt to improve child-care practices and the hygienic environment for the child, should focus on maternal literacy and simple health messages.
Early child health in Lahore, Pakistan: V. Feeding patterns.
The feeding practices of children (n = 1476) from birth to 24 months, as determined in a longitudinal study, in Lahore, Pakistan, are presented. Four socioeconomic groups at various levels of urbanization were included; a village, periurban slum, urban slum and an upper middle class. Initiation of breastfeeding was delayed in all the neonates. Sixty-five percent of the periurban slum mothers and 45% of the village mothers had not started breastfeeding at 48 hours after the birth of the infant. Prelacteal feedings, especially of herb water and honey, were the norm. Breastfeeding was highly prevalent. Eighty-seven to 98% of the infants in all the areas were breastfed at one month of age. Exclusive breastfeeding was rare, with 9% at one month, declining rapidly with age and being highly influenced by season. Partial breastfeeding was the most common mode of feeding. Water in addition to human milk was given by 45-73% of the mothers living in the urban slum, village and periurban slum at one month of age. Fresh animal milk and/or commercial formula was already being given at 1 month by 22-64% of the mothers in all areas. Commercial formula was the preferred food in the upper middle class, while in the other three areas it was rare and fresh animal milk was mainly used. More than 50% of the mothers in the village and in the periurban slum gave diluted animal milk even beyond the age of 10-15 months. In the upper middle class 50% of the infants were fed semisolids at the age of four months, while in the village, the periurban and the urban slum at 6 months of age only 10%, 12% and 47% of the infants received semisolids. The results of this study indicate that breastfeeding was highly prevalent in the three poorest areas. However, in all the areas initiation of breastfeeding was delayed and prelacteal feeding was the norm. Exclusive breastfeeding was rare, feeding bottles were used by 82-100% of the mothers to feed supplements and human milk substitutes, in the four areas.
Early child health in Lahore, Pakistan: VI. Morbidity.
Morbidity patterns were studied according to the age, area of living, sex and season among 1476 monthly followed infants born during 1984-1987 in four socio-economically different areas in Lahore, Pakistan. Infections were responsible for 87.0% of the morbidity during the first two years of life. The overall monthly based morbidity was 77.0% between birth and 24 months of age; diarrhoeal diseases 30.3%, upper and lower acute respiratory tract infections (ARI) 22.4%, skin and eye infections 6.7% and skin rash 6.2%. The vaccine-preventable diseases were only 0.5% of the total. Anaemia and rickets were rare (2.0%), but commonly seen among the nutritional deficiencies. Diarrhoea, tetanus, septicaemia, ARI and infections of the skin and eyes were reported more during earlier ages and from the three poorer areas of living. Diarrhoeal diseases, respiratory tract, skin and eye infections, in particular, followed clear seasonal patterns, while scabies prevailed throughout the year. The presence of these many preventable infections and illnesses implies that proper planning of interventions must be forthcoming.