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Biomedical subjects

S Ali

Publications and source records attributed to S Ali.

At least 253 records · Page 14Linked to original sources
PubMed1993

Production and characterization of monoclonal antibodies recognising defined regions of the human oestrogen receptor.

Mouse monoclonal antibodies were raised against the N-terminal (amino acids 151-165) and the very C-terminal (amino acids 578-595) regions of the human oestrogen receptor (hER). These antibodies recognise the hER by enzyme-linked immunosorbent assay, immunocytochemistry, immunoblotting, immunoprecipitation and gel retardation assays. The presence of hER is used prognostically in human breast cancer. We have tested the reactivity of our monoclonal antibodies on breast cancer sections, comparing with the commonly used Abbott rat monoclonal antibody H222. These studies show that the two monoclonal antibodies described here are highly versatile and will be useful tools for in vivo and in vitro studies of hER function. Furthermore, we show that the corresponding epitopes can be used as molecular "tags" for heterologous proteins and offer a powerful means of purifying and/or characterizing over-produced fusion proteins containing these regions.

Amino Acid Sequence↗
PubMed1993

Increased platelet cytosolic calcium responses to low density lipoprotein in type II diabetes with and without hypertension.

Non-insulin dependent diabetes mellitus (NIDDM) and hypertension are common diseases which are independently associated with insulin resistance/hyperinsulinemia, dyslysidemia, abnormalities of platelet function, and accelerated atherogenesis. The interaction of these independent risk factors is poorly understood. Recently, low density lipoprotein (LDL) receptors have been described, in platelets, and LDL elevates [Ca2+]i in these cells. In this study we have evaluated platelet [Ca2+]i responsiveness to LDL and arginine vasopressin (AVP) in NIDDM patients with (n = 28) and without (n = 13) concomitant hypertension, as well as in normal nondiabetic controls (n = 13). Platelet [Ca2+]i concentration-response curves to LDL for both NIDDM and hypertensive NIDDM were shifted significantly to the left when compared to the normotensive, nondiabetic controls. By contrast, no differences were seen in [Ca2+]i responses to 10 mumol/L AVP among any of the groups. To determine the possible role of hyperinsulinemia in this accentuated [Ca2+]i response to LDL, we measured basal and LDL-stimulated [Ca2+]i in platelets of normal volunteers after insulin treatment (0-100 mU/mL for 30 and 90 min). Insulin did not alter baseline or LDL-stimulated (150 mg/mL) platelet [Ca2+]i. Thus, an enhanced platelet [Ca2+]i response to LDL is characteristic of diabetes, independently of blood pressure. As such, it may also help to explain the enhanced platelet aggregation, endothelial dysfunction, and accelerated atherosclerosis of NIDDM.

Adult↗
PubMed1993

Asbestos induced oxidative injury to DNA.

DNA-damaging effects of asbestos in the presence of organic peroxides and hydroperoxides were investigated. The destabilization of the secondary structure of DNA, damage to deoxyribose sugar and DNA fidelity were measured, respectively, by S-1 nuclease hydrolysis, the formation of thiobarbituric acid (TBA)-reacting species and a melting temperature (Tm) profile using calf thymus DNA. S-1 nuclease hydrolysis and Tm determinations have shown that the presence of benzoylperoxide (BOOB), cumene hydroperoxide (COOH) or tertiary-butyl hydroperoxide (t-BOOH) increased asbestos-mediated DNA damage by a large factor compared either to asbestos alone or to peroxide or hydroperoxide alone. However, no formation of TBA-reacting species could be observed in this system. The quenchers of reactive oxygen species (ROS) afforded protection against DNA damage. These results suggest that asbestos in the presence of organic peroxides and hydroperoxides damage the DNA which is mediated by the generation of oxygen free radicals. The significance of these results in relation to the development of cancer of the respiratory tract among the asbestos exposed population is discussed.

Animals↗
PubMed1993

Leucocyte depletion attenuates the early increase in myocardial capillary permeability to small hydrophilic solutes following ischaemia and reperfusion.

OBJECTIVE: The aim was to assess the significance of polymorphonuclear leucocytes on the myocardial capillary permeability to a small hydrophilic indicator, on the vascular tone of the resistance vessels, and on contractile function following ischaemia and reperfusion. METHODS: Open chest, anaesthetised dogs were randomised to treatment with polyclonal antibody against polymorphonuclear leucocytes (anti-PMN group) or non-specific antibody (control group), and subjected to 40 min of coronary occlusion followed by 3 h of reperfusion. The capillary extraction fraction and the myocardial plasma flow rate were quantitated in vivo by intracoronary indicator bolus injection and external registration of the washout, and the capillary permeability-surface area product was calculated. Postischaemic vasodilator tone in the myocardial resistance vessels was measured by the local 133xenon washout method. RESULTS: 20 dogs were included (10 in each group), and 13 dogs completed the ischaemia-reperfusion protocol (anti-PMN group, n = 7; control group, n = 6). In the anti-PMN group, blood polymorphonuclear leucocyte counts were reduced to a minimum of 15% of pretreatment values. After ischaemia and 5 min reperfusion, the capillary extraction increased by 17% in the control group but decreased by 22% in the anti-PMN group (p < 0.05). The corresponding capillary permeability-surface area product increased by 22% in the control group, but decreased by 16% in the anti-PMN group (p < 0.05). Neither maximum myocardial plasma flow during reactive hyperaemia nor contractile function were influenced by anti-PMN treatment. CONCLUSIONS: Polymorphonuclear leucocytes appear to participate in the increase in myocardial capillary permeability observed early after reperfusion following a 40 min period of ischaemia, but do not influence postischaemic vascular tone or postischaemic contractile function. During normal physiological conditions reduction of the circulating polymorphonuclear leucocyte counts did not induce significant changes in myocardial capillary permeability.

Animals↗
PubMed1993

Does exclusion of enteral lipid assist remission in Crohn's disease?

Based on the improvement of Crohn's disease (CD) with elemental diets, we treated a patient with recurrent stenosing disease using prednisolone and drastic reduction of oral lipid intake. Complete symptomatic and good radiological improvement took place. A newly proposed hypothesis for CD suggests that enteral lipids together with certain luminal bacterial fragments become strongly antigenic to produce an inflammatory reaction analogous to the adjuvant response. Because of the apparent success of dietary lipid exclusion in this patient, we suggest that it be considered as a future option for management of acute CD.

Adult↗
PubMed1993

Detection of genome specific monomorphic loci in Bos taurus and Bubalus bubalis with oligodeoxyribonucleotide probe.

A synthetic oligodeoxyribonucleotide probe (OAT36) comprising nine repeats of 5'GACA 3' and several enzymes were used to analyse cow, (Bos taurus) and buffalo (Bubalus bubalis) genomes and a number of monomorphic loci were detected in both the species. Different animals from the same species showed an almost 'similar' monomorphic hybridization pattern but animals from two separate species showed a different 'genome specific' pattern. The overall hybridization with any enzyme and probe combination was found to be unique to one species. This forms the basis of genome specific hybridization which is substantiated by our zoo-blot hybridization studies. The evolutionary aspect of these loci in the context of sequence polymorphisms is discussed.

Animals↗
PubMed1993

Flow cytometric studies of ploidy and proliferative indices in the Yorkshire trial of adjuvant progestogen treatment of endometrial cancer.

OBJECTIVE: To estimate whether flow cytometric indices provide independent measures of prognosis or predict response to prophylactic progestogens in endometrial cancer. DESIGN: Endometrial tumour specimens were retrieved and analysed by flow cytometry from 257 women who had been randomly allocated in a previous trial to receive prophylactic progestogen in addition to conventional therapy for endometrial carcinoma. SETTING: Fourteen district and two teaching hospitals in West Yorkshire. SUBJECTS: Women developing primary endometrial cancer between 1975 and 1983. MAIN OUTCOME MEASURES: Tumour ploidy status and proliferative indices and the relation of these to tumour stage and grade, to prognosis and to response to progestogens. RESULTS: Ploidy status and proliferative indices were related to tumour stage, grade and patient survival but were not independent predictors of survival. They did not predict patients who would respond to progestogens although there was a nonsignificant trend towards patients with diploid tumours surviving longer after progestogen treatment. CONCLUSIONS: Flow cytometry adds little to established prognostic indicators for endometrial cancer.

Aged↗
PubMed1993

Adenosine in bronchoalveolar lavage fluid in asthma.

The inhalation of nebulized adenosine causes bronchoconstriction in asthmatics. In order to explore whether endogenously produced adenosine may contribute to the pathophysiologic aspects of asthma, we measured adenosine concentrations in bronchoalveolar lavage (BAL) fluid in seven subjects with asthma, eight asymptomatic cigarette smokers, and eight normal subjects. The mean concentration of adenosine in BAL fluid from the normal subjects was 0.72 +/- 0.16 microM. Subjects with asthma and cigarette smokers had significantly increased concentrations of adenosine in BAL fluid, 2.55 +/- 0.50 and 1.89 +/- 0.50 microM, respectively. Corrected for the dilution that occurs as a result of the lavage procedure, mean epithelial lining fluid adenosine concentrations were 60 +/- 13 microM in normal subjects, 193 +/- 58 microM in asthmatics, and 155 +/- 56 microM in smokers. Adenosine concentrations were positively correlated with the protein content of the lavage fluid (r = 0.79). Inhalation of nebulized adenosine in the subjects with asthma provoked a 20% reduction in lung function at concentrations 4- to 195-fold higher than was present in the epithelial lining fluid of the same individuals. The presence of increased BAL adenosine concentrations in asthmatics and in cigarette smokers suggests that adenosine may be a nonspecific marker for inflammation in the lung. The demonstration of physiologically relevant concentrations of adenosine in airway fluids of subjects with bronchial hyperreactivity to inhaled adenosine provides evidence for a role of endogenous adenosine in provoking bronchoconstriction in asthma.

Adenosine↗
PubMed1993

Production of mucinase and neuraminidase and binding of Shigella to intestinal mucin.

Production of mucinase and neuraminidase by Shigella spp. and their ability to bind to mucin was investigated. All four species of Shigella produced these enzymes. Virulent and avirulent pairs of Shigella did not differ in their ability to produce the enzymes after 18 h of growth. However, a significant difference in neuraminidase production was noted in Shigella dysenteriae type 1 and S. boydii (12-15) at 10 h growth. Avirulent strains of S. dysenteriae type 1, S. flexneri 2a, and S. boydii bound significantly more amounts of mucin than their virulent counterparts.

Animals↗
PubMed1992

Crystalline beta-cyclodextrin.12H2O reversibly dehydrates to beta-cyclodextrin.10.5 H2O under ambient conditions.

In contact with mother liquor, crystalline beta-cyclodextrin (beta-CD) hydrate has composition approximately beta-CD.12H2O. If crystals are dried at ambient conditions (18 degrees C, approximately 50% humidity), the unit cell volume diminishes approximately 30 to 50 A3. X-ray structure analysis of a dry crystal (0.89 A resolution, 4617 data, R = 0.059) showed the composition beta-CD.10.5 H2O, with approximately 5.5 water molecules in the beta-CD cavity (7 partially and 2 fully occupied sites) and approximately 5.0 between the beta-CD molecules. The positions of the beta-CD host and of most of the hydration waters are conserved during dehydration, but the occupancies of the waters in the beta-CD cavity diminish. Dry crystals put into solvent re-hydrate to the original form. The mechanism of de- and re-hydration is not evident.

Crystallization↗
PubMed1992

Adenosine-induced bronchoconstriction in an allergic rabbit model: antagonism by theophylline aerosol.

Recently, there has been an increasing interest in the involvement of adenosine as a mediator of allergic asthma. In the present study, we have employed an allergic rabbit model to study the airway responses to adenosine. The rabbit litter mates were injected i.p., within 24 h of birth, with ragweed pollen extract to preferentially produce ragweed-specific IgE. This allergic rabbit model demonstrates many clinical features of asthma similar to human allergic asthma. Aerosolized adenosine (0.156-10 mg/ml) caused a concentration-dependent bronchoconstriction. The normal rabbits (non-immunized) did not respond to adenosine within that concentration range. Theophylline significantly inhibited the adenosine-induced bronchoconstriction. These early studies suggest that adenosine differentiated asthmatic airways from normal airways and adenosine-induced bronchoconstriction in this model was mediated through specific cell surface receptor(s).

Adenosine↗
PubMed1992

Modification of allergen-induced airway obstruction and bronchial hyperresponsiveness in the allergic rabbit by theophylline aerosol.

The effects of theophylline on allergen-induced airway obstruction and bronchial hyperresponsiveness were investigated in allergic rabbits. This allergic rabbit model was developed in our laboratory and stimulates the human model of allergic asthma in several aspects. Four allergic rabbits with hyperreactive airways were challenged with ragweed to elicit early- and late-phase asthmatic responses and subsequent increased airway responsiveness. Two to three weeks later, the rabbits received theophylline (5 mg/ml, nebulized for 3 min) prior to a second allergen challenge. Theophylline significantly inhibited the allergen-induced early- and late-phase asthmatic responses by 38% (P < 0.05) and 49% (P < 0.05), respectively. Further theophylline inhibited the allergen-induced increase in lung resistance by 42% (P < 0.05) during the late-phase responses. Theophylline also inhibited the allergen-induced bronchial hyperresponsiveness by 39% (P < 0.05) at 24 h. These data suggest a potential anti-inflammatory effect of theophylline in preventing allergen-induced asthmatic responses and bronchial hyperresponsiveness.

Aerosols↗
PubMed1992

Immunodetection of multiple species of retinoic acid receptor alpha: evidence for phosphorylation.

Polyclonal and monoclonal antibodies were raised against synthetic peptides (or fusion protein) corresponding to cDNA-deduced amino acid sequences unique to the human and mouse retinoic acid (RA) receptor alpha 1 (hRAR-alpha 1 and mRAR-alpha 1, respectively). Two rabbit polyclonal antibodies directed against either the F region fused to DHFR [RP alpha (F)] or the D2 region [RP alpha (D2)] were selected. Using either immunocytochemistry, Western blotting analysis, or immunoprecipitation, they were found to be specific for human and mouse RAR-alpha 1 proteins produced by COS-1 cells transiently transfected with vectors expressing the RAR-alpha 1 cDNA. Three mouse monoclonal antibodies directed against either the F region [(Ab9 alpha (F) and Ab12 alpha (F)] or the A1 region [Ab10 alpha 1(A1)] recognized transiently expressed human and mouse RAR-alpha 1 proteins, when either immunocytochemistry or immunoprecipitation was used. In addition, Ab9 alpha (F) and Ab12 alpha (F), but not Ab10 alpha 1(A1), revealed the RAR-alpha 1 proteins by Western blotting analysis. Ab9 alpha (F) was also able to "supershift" RAR-alpha 1 protein-RARE oligonucleotide probe complexes in gel retardation assays. All these antibodies recognized also the transiently expressed mRAR-alpha 2 isoform, with the exception of Ab10 alpha 1 (A1), which is specific for the A1 region of RAR-alpha 1. These antibodies have enabled us to detect the presence of mRAR-alpha as multiple species in mouse embryo and adult tissue extracts as well as in embryonal carcinoma (EC) cells. Moreover, we found that one of these species (51 kDa) was phosphorylated in EC cells. This phosphorylation was not affected by RA treatment, but appeared to be dependent on the differentiation state of the EC cells.

Amino Acid Sequence↗
PubMed1992

A synthetic oligonucleotide probe (5'TTCCA 3')n uncovers a male specific hybridization pattern in the human genome.

A pentanucleotide motif 5'TTCCA3', originating from a 3.4 kb repeat fraction (DYZ1)1, is organized tandemly in the human genome. This motif is abundantly present on the long arm of the human Y (band Yq12) chromosome and is separated by Hae III digestion of male genomic DNA. We have developed a 20 base synthetic oligonucleotide probe, termed OAT20Y, comprising four repeat units of 5'TTCCA3', that uncovers a male-specific hybridization pattern in the human genome. The probe is highly sensitive, since less that 1 micrograms of DNA was sufficient to obtain visible signals after hybridization. Our results on discrimination of sex by using OAT20Y with several amniotic fluid samples was in accordance with clinical data. OAT20Y was found to be specific to the human genome as it did not hybridize with DNA of any non-human species. In addition to sexing human embryos in conjunction with severe X-linked genetic diseases, the probe may be useful in ascertaining the origin of tissues or blood samples in forensic cases.

Amniotic Fluid↗
PubMed1992

Retinoic acid receptor-beta: immunodetection and phosphorylation on tyrosine residues.

Polyclonal (RP) and monoclonal (Ab) antibodies were raised against synthetic peptides (or fusion proteins) corresponding to amino acid sequences unique to human and mouse retinoic acid receptor-beta (RAR beta) isoforms. Antibodies directed against the A2 region [Ab6 beta 2(A2), Ab7 beta 2(A2), and RP beta 2(A2)], the D2 region [RP beta(D2)], or the F region [Ab8 beta(F)2, RP beta(F)1, and RP beta(F)2] were selected. The monoclonal and polyclonal antibodies directed against the D2 and F regions specifically immunoprecipitated and recognized by Western blotting all human and mouse RAR beta isoforms (mRAR beta 1, -beta 2, -beta 3, and -beta 4), produced in COS-1 cells transfected with expression vectors containing the corresponding RAR beta cDNA. Furthermore, in gel retardation assays, the monoclonal antibodies supershifted RAR beta protein-RA response element oligonucleotide complexes. Antibodies directed against the A2 region were specific for the RAR beta 2 isoform. The above antibodies allowed us to detect the presence of mRAR beta 2 proteins in mouse embryos and to show that their presence in embryonal carcinoma cells (F9 and P19 cell lines) is dependent upon RA treatment. The antibodies were also used to demonstrate that RAR beta proteins produced by transfection in COS-1 cells are phosphorylated. RAR beta 2 phosphorylation was not affected by RA treatment, whereas the phosphorylation of RAR beta 1 and RAR beta 3 isoforms was greatly enhanced by RA. We also show that, in contrast to RAR alpha 1 and RAR gamma 1, RAR beta 2 proteins contain phosphotyrosine residues and are only weakly phosphorylated in vitro by cAMP-dependent protein kinase. These results support our previous proposal that the various receptors have distinct functions in the RA-signaling pathway.

Amino Acid Sequence↗
PubMed1992

Expression of prolactin and its receptor in human lymphoid cells.

We have investigated whether human lymphoid cells are able to synthesize and secrete human PRL (hPRL) and to express PRL receptors. Metabolic labeling with [35S]methionine and immunoprecipitation of cell extracts from human mononuclear cells (MNC) and a human T lymphocyte cell line with an antiserum against hPRL revealed protein of M(r) 23,000, identical in size to pituitary hPRL. Dilution curves of lymphocyte immunoreactive hPRL were parallel to those obtained with pituitary hPRL in an immunoradiometric assay using two monoclonal antibodies against hPRL. Polymerase chain reaction experiments with primers located in the coding sequence of hPRL showed that the hPRL gene was expressed in MNC. Furthermore, cDNA cloning and sequence analysis indicated the presence of an extra 5' noncoding exon previously described for decidual hPRL. When MNCs were further separated into B cells, T cells, and monocytes, the expression of hPRL appeared to be mainly associated with the T lymphocyte fraction. The hPRL transcript was also detected in thymocytes and in a set of human lymphoid cell lines. Finally, polymerase chain reaction experiments revealed a ubiquitous distribution of PRL receptor gene expression in B cells, T cells, and monocytes. The presence of the receptor for PRL and production of PRL by T lymphocytes suggest a possible autocrine or paracrine effect of PRL in immune cell function.

Base Sequence↗