Sexual and treatment behaviour of STD patients.
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Asia↗
Biomedical subjects
P Kaur
Publications and source records attributed to P Kaur.
Verocytopathic activity of Escherichia coli O157 & other 'O' serogroups isolated from patients of diarrhoea.
Twenty diarrhoeal isolates identified as Esch. coli O157 were screened for cytopathic activity on the continuous Vero cell line. Of these, seven strains (35%) showed cytopathic effect which was maximum on the 4th day after inoculation, with a maximum titre of 1 in 128. The total loss of cytopathic activity was observed in the positive filtrates subjected to a temperature of 100 degrees C for 15 min, while heating at 65 degrees C for 15 min, resulted in partial loss of this activity. All the verocytopathic strains were obtained from infants and children and were devoid of heat labile (LT) and heat stable (ST) toxins as well as enteroinvasive property.
Adolescent↗
Phosphorylation of the small heat-shock protein is regulated by interleukin 1, tumour necrosis factor, growth factors, bradykinin and ATP.
Interleukin 1 (IL1) increased phosphorylation of the small heat-shock protein (hsp 27) in MRC5 fibroblasts. The increase was maintained for at least 30 min, but levels had returned to pre-stimulation values by 2 h. When hsp 27 was metabolically labelled with [3H]leucine, about 15% was phosphorylated in resting confluent cells; this rose to 90% upon stimulation by IL1. Peptide maps of the three differently charged phosphorylated forms were consistent with their arising by phosphorylation of increasing numbers of serine residues. IL1 had the same effect on hsp 27 in pig articular chondrocytes, endothelial cells from human umbilical vein and an epidermoid carcinoma cell line (KB). Certain other agents were found selectively to increase phosphorylation of hsp 27 in MRC5 cells besides IL1 [and tumour necrosis factor (TNF)]. Platelet-derived growth factor had a similar effect to that of IL1; bradykinin, acid fibroblast growth factor and ATP caused an intermediate effect; phorbol myristate acetate (PMA) and 1-oleoyl-2-acetylglycerol had smaller effects. Dibutyryl cyclic AMP and forskolin had no effects on hsp 27 phosphorylation. When cells had been depleted of protein kinase C (PKC) by prolonged treatment with PMA, stimulation by IL1, TNF or bradykinin still increased hsp 27 phosphorylation. The stimulation by all three agents was also unaffected by the PKC inhibitor staurosporine. IL1, TNF and bradykinin each caused hsp 27 phosphorylation by a pathway independent of PKC. The results are consistent with IL1 activating a serine kinase which remains to be identified.
Adenosine Triphosphate↗
Hereditary ovarian cancer. Heterogeneity in age at diagnosis.
An unknown fraction of the ovarian cancer burden occurs in women with a family history indicative of a putative autosomal dominantly inherited cancer susceptibility syndrome. The results from a five-generation, extended, hereditary breast-ovarian cancer kindred are described 10 years after it was initially ascertained. Significantly more cancers were observed in high-risk family members during this decade than were expected (P less than 0.001). The age of ovarian cancer diagnosis was studied in additional ovarian cancer-prone families of three types: site-specific ovarian cancer syndrome, the breast-ovarian cancer syndrome, and Lynch syndrome II. The age of onset in each of the three sets was significantly (P less than 0.001) earlier than the general population mean of 59, and there were significant differences in the age of onset (P = 0.050) among these three cohorts. Ovarian cancer histology was similar to that of patients with negative family histories. There may be clinically significant heterogeneity in the age at diagnosis of ovarian cancer among these ovarian cancer-prone syndromes. This has important implications for understanding its natural history and targeting surveillance-management strategies.
Adult↗
Substrate-induced dimerization of the ArsA protein, the catalytic component of an anion-translocating ATPase.
The ArsA protein, the catalytic component of the plasmid-encoded resistance system for removal of the toxic oxyanions arsenite, antimonite, and arsenate from bacterial cells, catalyzes oxyanion-stimulated ATP hydrolysis. Three lines of evidence suggest that the ArsA protein functions as a homodimer. First, the ArsA protein was modified with 5'-p-fluorosulfonyl-benzoyladenosine (FSBA). Antimonite potentiated FSBA inhibition, while ATP or ADP afforded partial protection. ATP and antimonite together provided complete protection, indicating interaction of the anion- and nucleotide-binding sites. The estimated Ki values for FSBA were 0.4 mM in the absence of antimonite and 0.1 mM in the presence of antimonite, suggesting that the binding of antimonite increased the affinity of ArsA protein for FSBA. Incorporation of [14C]FSBA was examined. Extrapolation of the amount of FSBA required to inactivate the protein indicated that 1 mol of FSBA was sufficient to inhibit the activity of 1 mol of ArsA protein in the absence of substrates, while only 0.5 mol was required in the presence of the anionic substrate antimonite. Second, chemical cross-linking of the 63-kDa ArsA protein with N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline resulted in formation of a species approximately twice the size of the monomer in the presence of antimonite but not ATP. Third, determination of the average mass of the ArsA protein in solution by light scattering demonstrated that the average species was 66 kDa in the absence of substrates. In the presence of antimonite the weight average molecular mass increased to a mass in excess of 100 kDa. These results are consistent with the ArsA protein existing in an equilibrium between monomer and dimer, with the equilibrium favoring dimerization upon binding of the anionic substrate. Moreover, total loss of ATPase activity in the half-modified enzyme suggests that the catalytic sites on each monomer must interact.
Adenosine↗
Progression of human papillomavirus type 18-immortalized human keratinocytes to a malignant phenotype.
We have developed a model system for progression of human epithelial cells to malignancy, using a human papillomavirus type 18 (HPV-18)-immortalized human keratinocyte cell line. Cells of cell line FEP-1811 were nontumorigenic in athymic mice through at least 12 passages in culture, but after 32 passages were weakly tumorigenic, producing tumors that regressed. After 62 passages they produced invasive squamous cell carcinomas that grew progressively. The progression to malignancy was associated with an increase in the efficiency of forming colonies in soft agar and with altered differentiation properties. In an organotypic culture system, FEP-1811 cells at passages 12 and 32 exhibited features typical of premalignant intraepithelial neoplasia in vivo, and cells at passage 68 exhibited features consistent with squamous cell carcinomas. No change in copy number of the transfected HPV-18 genome or in the level of expression of the viral transforming gene products E6 and E7 was detected between tumorigenic and nontumorigenic cells. Cytogenetic analysis of cells at early, middle, and late passage levels and cells cultured from tumors revealed that several chromosomal abnormalities segregated with the tumorigenic cell populations.
Animals↗
Histochemical and biochemical studies on esterase activity in the rat ovary.
A correlative histochemical and biochemical study has been made of the changes in esterase positive sites in immature (10-, 20- and 30-days old), mature normal cycling (3-, 5- and 8-months-old), pregnant and lactating rat ovaries. The typical perivascular esterase-positive sites localized in the hilar portion, branch along the blood vessels and traverse into medullary and cortical portions of the ovary. The stromal vascularity surrounding the normal developing follicles, corpora lutea, atretic follicles and interstitial gland tissue showed rich activity of this enzyme system. On semiquantitative basis the number, intensity and quantity of esterase-positive sites vary with the maturation and reproductive states of the rat. The administration of estradiol-17 beta increased the fine perifollicular and theca externa perivascular esterase-positive sites, whereas atropine and reserpine affected severely both the large and fine meshwork of esterase-positive sites. Biochemical estimates of acetylcholine esterase activity endorse these histochemical observations. The possible roles of AChE activity in varied ovarian functions are discussed.
Acetylcholinesterase↗
A plasmid-encoded anion-translocating ATPase.
An anion-translocating ATPase has been identified as the product of the arsenical resistance operon of resistance plasmid R773. When expressed in Escherichia coli this ATP-driven oxyanion pump catalyzes extrusion of the oxyanions arsenite, antimonite and arsenate. Maintenance of a low intracellular concentration of oxyanion produces resistance to the toxic agents. The pump is composed of two polypeptides, the products of the arsA and arsB genes. This two-subunit enzyme produces resistance to arsenite and antimonite. A third gene, arsC, expands the substrate specificity to allow for arsenate pumping and resistance.
Adenosine Triphosphatases↗
Synthesis, crystal structure, and molecular conformation of peptide N-Boc-L-Pro-dehydro-Phe-L-Gly-OH.
The peptide N-Boc-L-Pro-dehydro-Phe-L-Gly-OH was synthesized by the usual workup procedure and finally coupling the N-Boc-L-Pro-dehydro-Phe to glycine. The peptide crystallizes in monoclinic space group P2(1) with a = 8.951(4) A, b = 5.677(6) A, c = 21.192(11) A, beta = 96.97(4) degrees, V = 1069(1) A3, Z = 2, dm = 1.295(5) Mgm-3, and dc = 1.297(4) Mgm-3. The structure was determined by direct methods using SHELXS86. The structure was refined by the block-diagonal least-squares procedure to an R value of 0.074 for 1002 observed reflections. The C alpha 2-C beta 2 distance of 1.33(2) A is an appropriate double bond length. The angle C alpha 2-C beta 2-C gamma 2 is 133(1) degrees. The peptide backbone torsion angles are theta 1 = -167(1) degrees, omega 0 = 179(1) degrees, phi 1 = -48(1) degrees, psi 1 = 137(1) degrees, omega 1 = 175(1) degrees, phi 2 = 65(2) degrees, psi 2 = 15(2) degrees, omega 2 = -179(1) degrees, and phi 3 = -166(1) degrees. These values show that the Boc group has a trans-trans conformation while the peptide backbone adopts a beta-turn II conformation, which is stabilized by an intramolecular hydrogen bond of length of 3.05(1) A. The structures of dehydro-Phe containing peptides suggest that the dehydro-Phe promotes the beta-turn II conformation. The five-membered pyrrolidine ring of the Pro residue adopts an ideal C gamma-exo conformation with torsion angles chi 1(1) = -24(1) degrees, chi 2(1) = 34(1) degrees, chi 3(1) = -30(1) degrees, chi 4(1) = 15(1) degrees, and theta 0(1) = 6(1) degrees. The side-chain torsion angles in dehydro-Phe are chi 1(2) = -1(2) degrees, chi 2,1(2) = -176(1) degrees, and chi 2,2(2) = 8(2) degrees. The plane of C alpha 2-C beta 2-C gamma 2 is rotated with respect to the plane of the phenyl ring at 7(1) degrees, which indicates that the atoms of the side chain of dehydro-Phe are essentially coplanar. The molecules form a 2(1) screw axis related hydrogen-bonded rows along the b axis.
Amino Acid Sequence↗
The role of integrins alpha 2 beta 1 and alpha 3 beta 1 in cell-cell and cell-substrate adhesion of human epidermal cells.
We have examined cultures of neonatal human foreskin keratinocytes (HFKs) to determine the ligands and functions of integrins alpha 2 beta 1, and alpha 3 beta 1 in normal epidermal stratification and adhesion to the basement membrane zone (BMZ) in skin. We used three assay systems, HFK adhesion to purified extracellular matrix (ECM) ligands and endogenous secreted ECM, localization of integrins in focal adhesions (FAs), and inhibition of HFK adhesion with mAbs to conclude: (a) A new anti-alpha 3 beta 1 mAb, P1F2, localized alpha 3 beta 1 in FAs on purified laminin greater than fibronectin/collagen, indicating that laminin was the best exogeneous ligand for alpha 3 beta 1. However, in long term culture, alpha 3 beta 1 preferentially codistributed in and around FAs with secreted laminin-containing ECM, in preference to exogenous laminin. Anti-alpha 3 beta 1, mAb P1B5, detached prolonged cultures of HFKs from culture plates or from partially purified HFK ECM indicating that interaction of alpha 3 beta 1 with the secreted laminin-containing ECM was primarily responsible for HFK adhesion in long term culture. (b) In FA assays, alpha 2 beta 1 localized in FAs conincident with initial HFK adhesion to exogenous collagen, but not laminin or fibronectin. However, in inhibition assays, anti-alpha 2 beta 1 inhibited initial HFK adhesion to both laminin and collagen. Thus, alpha 2 beta 1 contributes to initial HFK adhesion to laminin but alpha 3 beta 1 is primarily responsible for long-term HFK adhesion to secreted laminin-containing ECM. (c) Serum or Ca2(+)-induced aggregation of HFKs resulted in relocation of alpha 2 beta 1 and alpha 3 beta 1 from FAs to cell-cell contacts. Further, cell-cell adhesion was inhibited by anti-alpha 3 beta 1 (P1B5) and a new anti-beta 1 mAb (P4C10). Thus, interaction of alpha 3 beta 1 with either ECM or membrane coreceptors at cell-cell contacts may facilitate Ca2(+)-induced HFK aggregation. (d) It is suggested that interaction of alpha 3 beta 1 with a secreted, laminin-containing ECM in cultured HFKs, duplicates the role of alpha 3 beta 1 in basal cell adhesion to the BMZ in skin. Further, relocation of alpha 2 beta 1 and alpha 3 beta 1 to cell-cell contacts may result in detachment of cells from the BMZ and increased cell-cell adhesion in the suprabasal cells contributing to stratification of the skin.
Antibodies↗
Distinct functions for integrins alpha 3 beta 1 in focal adhesions and alpha 6 beta 4/bullous pemphigoid antigen in a new stable anchoring contact (SAC) of keratinocytes: relation to hemidesmosomes.
Basal cells of stratified epidermis are anchored to the basement membrane zone (BMZ) of skin via hemidesmosomes. We previously identified integrin alpha 3 beta 1, in focal adhesions (FAs), of cultured human keratinocytes (HFKs) as a mediator of HFK adhesion to secreted BMZ-like extracellular matrix (ECM; Carter, W.G., E.A. Wayner, T.S. Bouchard, and P. Kaur. 1990. J. Cell Biol. 110: 1387-1404). Here, we have examined the relation of integrins alpha 6 beta 4 and alpha 3 beta 1, to bullous pemphigoid antigen (BPA), a component of hemidesmosomes. We conclude that alpha 6 beta 4 in HFKs localizes in a new stable anchoring contact (SAC) that cooperates with alpha 3 beta 1-FAs to mediate adhesion to ECM, based on the following. (a) Comparison of secreted ECM, with exogenous laminin, fibronectin and collagen identified ECM as the preferred ligand for HFK adhesion and spreading and for formation of both alpha 6 beta 4-SACs and alpha 3 beta 1-FAs. (b) Inhibition of HFK adhesion with combined anti-alpha 3 beta 1 (P1B5) and anti-alpha 6 beta 4 (GoH3) antibodies indicated that both receptors were functional in adhesion to ECM while alpha 3 beta 1 played a dominant role in spreading. (c) alpha 6 beta 4 colocalized with BPA in SACs that were proximal to but excluded from FAs. Both alpha 6 beta 4-SACs and alpha 3 beta 1-FAs were in contact with the adhesion surface as indicated by antibody exclusion and interference reflection microscopy. (d) In contrast to alpha 3 beta 1-FAs, alpha 6 beta 4-SACs were present only in nonmotile cells, not associated with stress fibers, and were relatively stable to detergents and urea, suggesting a nonmotile, or anchoring function for SACs and motility functions for alpha 3 beta 1-FAs. (e) alpha 6 beta 4 formed a detergent-insoluble complex with exogenous ECM in an affinity isolation procedure, confirming the ability of an unidentified ECM ligand to interact with alpha 6 beta 4. (f) We suggest that alpha 6 beta 4/BPA-SACs in culture restrict migration of HFKs on ECM while alpha 3 beta 1-FAs form dynamic adhesions in spreading and migrating cells. alpha 6 beta 4/BPA-SACs in culture bear functional and compositional similarities to hemidesmosomes in skin.
Autoantigens↗
Synthetic, immunological and structural studies on repeat unit peptides of Plasmodium falciparum antigens.
Using solid phase methodology, we have synthesized five peptides (16-18 residues long) corresponding to repeat sequences of four antigens of a human malarial parasite, Plasmodium falciparum. Three of these antigens (RESA, FIRA, and ABRA) are found in the asexual blood-stages of the parasite, while the remaining one (CSP) is found in the sporozoites. The synthetic peptides, conjugated to bovine serum albumin, elicited high levels of antibodies in rabbits, and these antibodies were found to cross-react with the heterologous peptides. The degree of cross-reactivity, as estimated in an ELISA, was quite remarkable among all the peptides. The peptide corresponding to the RESA tetrapeptide repeat was found to be the most immunogenic and highly cross-reactive. For this reason this tetrapeptide repeat unit, peptide 1, may be a suitable candidate for inclusion in a multiple epitope polypeptide vaccine design. Conformational studies using circular dichroism spectroscopy show that these peptides have similar conformational characteristics with a common feature of approximately 30% and approximately 50% helical content water and TFE respectively. Theoretical predictions regarding conformation using the Chou-Fasman method have also been presented.
Amino Acid Sequence↗
Reye and Reye-like syndromes: results of a pilot study in Peninsular Malaya, 1986.
A pilot epidemiologic study of all cases of Reye and Reye-like syndromes was undertaken at 8 representative major hospitals in Peninsular Malaya from January 1st to December 31st 1986. The cases were classified as definitive Reye's syndrome, clinical Reye's syndrome and encephalo-hepatopathies. Less than 50% of cases reviewed fulfilled the National Center for Disease Control criteria for clinical Reye's syndrome. Causes of Reye-like syndromes/encephalo-hepatopathies included fulminant hepatitis, Japanese B encephalitis, dengue, septicaemia, and complex febrile fits. It was not possible to differentiate clinical Reye's syndrome from the other encephalo-hepatopathies by either the clinical features (except for jaundice) or biochemical parameters. Liver biopsy is necessary for a definitive diagnosis of Reye's syndrome in Malaysia, because of the high prevalence of Reye-like diseases. The mortality rate in the 2 groups of patients is similar. Ingestion of salicylates was not found to be significantly associated with Reye and Reye-like syndromes in this study.
Diagnosis, Differential↗
IL-1 signal transduction: evidence of activation of G protein and protein kinase.
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Animals↗
Temporary endodontics during active orthodontics.
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Calcium Hydroxide↗
Litholapaxy: a fading art.
The bladder stones in 45 patients were treated with tactile litholapaxy over a period of 3 years. The overall success rate was 91.1%. The associated urological lesions like enlarged prostate, bladder neck contracture and urethral stricture could be safely dealt with simultaneously with litholapaxy in one sitting which was advantageous to the patient as well as to the surgeon.
Adolescent↗
Cytogenetic analysis of eight human papillomavirus immortalized human keratinocyte cell lines.
Cytogenetic analysis was performed on human papillomavirus (HPV)-immortalized cell lines. Lines were established by co-transfection of primary human keratinocyte cells with HPV type 16 or 18 DNA and pSV2neo. The resulting clonal lines contained integrated HPV DNA and exhibited extended life spans in culture but were non-tumorigenic in nude mice. Two HPV16-immortalized lines (FEPE1L8 and FEPE1L9) and 4 HPV18-immortalized lines (FEA, FEH18L, FEP18-5 and FEP18-11) were established. Two additional lines were derived by subsequent treatment of the FEA line with TPA and by further transfection with HSVII DNA. Cytogenetic analysis revealed that all lines were abnormal, containing a variety of numerical and structural aberrations. Six of the 8 lines were hyper-triploid and 2 were near-diploid. Examination of lines FEA, FEH18L and FEP18-11 at multiple passages in culture revealed that the lines were clonal and chromosomally stable over extended passage in culture. Structural rearrangements were most common in chromosomes 1 and 3 but also occurred in chromosomes 5, 7, 8, 12, 16 and 22. Marker chromosomes were present in all cell lines. A small metacentric marker, possibly an isochromosome for the short arm of chromosome 5, was consistently present in the FEA line and its derivatives (FEAB10 and FEAT) as well as the FEH18L line. A loss or reduction in copy number of chromosome 13 was seen in 5 of the 8 cell lines.
Aneuploidy↗
Interleukin 1 and tumour necrosis factor increase phosphorylation of the small heat shock protein. Effects in fibroblasts, Hep G2 and U937 cells.
Interleukin 1 alpha and tumour necrosis factor-alpha stimulated phosphorylation of three 27 kDa phosphoproteins in MRC-5 fibroblasts which was sustained for up to 2 h after adding the cytokines. All three phosphoproteins were immunoprecipitated by a specific antiserum to the small mammalian heat shock protein, hsp 27. The three phosphoproteins from stimulated or control cells contained phosphoserine but not phosphothreonine or phosphotyrosine. Similar increases in phosphorylation of immunoprecipitable 27 kDa proteins were seen in U937 cells stimulated by TNF alpha and Hep G2 cells stimulated by IL1 alpha.
Animals↗