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Biomedical subjects

S Khalaf

Publications and source records attributed to S Khalaf.

At least 19 recordsLinked to original sources
PubMed2006

Cyclo-oxygenase-2 (COX-2) mRNA expression and hormone receptor status in breast cancer.

AIMS: The purpose of this study was to evaluate COX-2 mRNA expression with known clinical prognostic features of breast cancer, oestrogen/progesterone receptor status, tumour size and grade. METHODS: Total RNA was extracted from 45 frozen breast tumour (invasive) and 22 normal breast tissue samples. COX-2 mRNA transcription was quantified using a real time RT-PCR assay and expressed as copy number/microg total RNA. All specimens were assessed for tumour grade, size, nodal status and presence of vascular invasion and oestrogen and progesterone receptor status. RESULTS: COX-2 mRNA was detected in all samples with a median copy number of 1.15 x 10(7) for tumours and 6.5 x 10(6) for normal samples. Expression was significantly higher in oestrogen receptor negative tumours compared to the receptor positive group. There was no correlation between COX-2 mRNA levels and tumour size, grade, nodal status and presence of vascular invasion. CONCLUSIONS: COX-2 mRNA expression is increased in oestrogen and progesterone receptor negative breast cancers.

Breast↗
PubMed2005

Differential expression of IGF-binding protein-3 in normal and malignant colon and its influence on apoptosis.

IGF-binding protein-3 (IGFBP-3) has been reported to exert a protective influence on the pathogenesis of colorectal cancer. This may reflect its modulation of IGF-I bioactivity as well as IGF-I-independent effects on cell proliferation and apoptosis. Although local expression of IGF-I in the colon is increasingly recognised as having important regulatory consequences, the role of locally expressed IGFBP-3 remains unknown. The aims of the present study were: (i) to quantify and localise the expression of IGFBP-3 in human normal and malignant colon; (ii) to relate this expression to that of other components of the IGF-I axis; and (iii) to investigate the effects of IGFBP-3 on colonic epithelial cell proliferation and apoptosis. RNA was extracted from 46 paired samples of normal and malignant colonic tissue. IGFBP-3, IGF-I, IGF-I receptor and GH receptor mRNA levels were quantified using real-time RT-PCR. Laser-capture microdissection of the same samples was used to isolate mRNA from epithelium and stromal components and localise mRNA expression. Expression was confirmed at a protein level by immunohistochemistry. Human colorectal cancer HT-29 and CaCo-2 cells were cultured with IGFBP-3 (200 ng/ml), +/- IGF-I (20 ng/ml), +/- sodium butyrate (5 mM). Cell number was assessed by an MTS assay (a modification of the MTT assay), and apoptosis assessed by cell morphology and FACS analysis using both annexin and propidium iodide staining. UO146, a MAP kinase inhibitor, and wortmannin, an inhibitor of the phosphatidylinositol 3-kinase (PI-3K) pathway, were used to determine the contribution of these signalling pathways on the effects of IGFBP-3. IGFBP-3 mRNA was detected in all samples (mean copy number/mug total RNA in normal colon, 2.6 x 10(6) compared with 1.3 x 10(7) in the cancers; P < 0.0001). Immunohistochemistry confirmed the expression and showed it to be equally distributed between epithelial and stromal components in normal tissue, but to be mainly restricted to the stromal component of malignant tissue. This differential expression was confirmed by RT-PCR of RNA from laser-capture microdissected samples. IGF-I mRNA was detected in 31 samples of normal colon; mean IGFBP-3 copy number was higher in the IGF-I-positive samples compared with IGF-I-negative samples. IGFBP-3 on its own induced apoptosis in HT-29 cells (P < 0.001). Co-incubation of 200 ng/ml IGFBP-3 with butyrate (5 mM) resulted in the potentiation of its apoptosis (P < 0.0001), which was not rescued by co-incubation with IGF-I (P < 0.0001). The addition of UO126 caused a decrease in cell number and increased the effects of IGFBP-3. IGFBP-3 is differentially expressed between stromal and epithelial components of normal and malignant colon, which may reflect its pro-apoptotic, IGF-I-independent effect on colonic epithelial cells. These effects are mediated in part by the PI-3K pathway in contrast to the MAP kinase pathway used by IGF-I.

Apoptosis↗
PubMed2002

Excretory/secretory products of Haemonchus contortus inhibit aminopyrine accumulation by rabbit gastric glands in vitro.

Abomasal parasites inhibit gastric acid secretion and reduce the number of acid secreting parietal cells either through physical contact with gastric tissue, the release of inhibitory excretory/secretory (ES) products or by initiating the host inflammatory response. To examine the role of parasite ES products, adult Haemonchus contortus were incubated in a medium based on Hank's balanced salt solution and three incubates were tested for the presence of inhibitors of acid secretion by dispersed rabbit gastric glands in vitro, using the intracellular accumulation of 14C-aminopyrine (AP) as an indirect measure of acid secretion. Acceptably sensitive rabbit preparations (80%) for testing ES products showed increased 14C-AP accumulation with either 10(-5) or 10(-4)M histamine. Sheep glands proved unsuitable as a test system as only two of six preparations responded weakly to histamine. Inhibitory activity was demonstrated in all the three parasite incubates, although responses varied quantitatively between tests, even with the same batch of incubate. In single tests, 16% ES products significantly reduced the 14C-AP ratio (P<0.05) of 10(-4)M histamine-stimulated glands (15 of 19 tests with Batch 1 and two of six with Batch 3). Even at 1 and 5%, ES products (Batch 2) were inhibitory for 10(-5)M histamine-stimulated glands: at 1% the mean reduction was 26.0% (range 7.8-54.8%, n=10), four of which were statistically significant and at 5% was 17.6% (range -15.3-53.8%, n=17), four of which were statistically significant. ES products were overall inhibitory (-12%, P<0.05), when tested on glands exposed to increasing histamine concentrations from 10(-6)M to 10(-3)M (which increased the 14C-AP ratio (P<0.001)). Responses by individual gland preparations differed (P<0.001). The active component(s) of the parasite ES products were less than 5000 molecular weight. Ammonium chloride, tested over the range of concentrations of ammonia present in worm incubates (0.2-1 mM, final concentrations in the gland incubations of 0.005-0.1 mM), had variable, but overall inhibitory effects on 10(-5)M histamine-stimulated glands (n=3). When tested with a range of histamine concentrations, 0.01 mM NH4Cl overall reduced the response by 8.6% (P<0.05)(n=4). The similarity of responses of rabbit glands to parasite ES products and to NH4Cl suggests that ammonia may be the small molecular weight ES product of adult H. contortus, which inhibited acid secretion in vitro.

Aminopyrine↗
PubMed2000

A sequential study of the pathology associated with the infection of sheep with adult and larval Ostertagia circumcincta.

Disturbances in the physiology of the abomasa of sheep infected with either adult Ostertagia circumcincta given via abomasal cannulae, or larvae (L3) given intraruminally were matched by pathological changes in tissues collected by repeated mucosal biopsy. Within 2-3 days of the transplant of adult worms, abomasal pH had increased markedly in five out of six animals, and there also had been rapid increases in serum gastrin and pepsinogen concentrations in all animals. Reductions in parietal cell number were recorded as early as 1 day after the transplant of adults and were associated with the rapid accumulation of many neutrophils and eosinophils. Mucosal hyperplasia, with increased numbers of cells closer in appearance to mucous/mucous neck cells, was a relatively late development, being most pronounced in the latter part of the infection. In sheep given larvae, changes in secretory physiology were again matched by a concurrent fall in parietal cell number and by the accumulation of inflammatory cells. Changes became maximal when most worms could be expected to be present as adults, confirming the role of adults in the natural disease. Some abnormalities were detected in biopsies collected from animals maintained free of parasites and, although milder in degree, there were similarities to those observed in parasitised tissues, there being fewer parietal cells, a modest degree of mucous cell hyperplasia and inflammatory infiltrates of predominantly neutrophils. These changes were the likely result of trauma to the tissues in the immediate vicinity of the cannula, due either to the presence of the cannula itself or to the frequent collection of biopsy material from areas close to it.

Animals↗
PubMed2000

Human elastase 1: evidence for expression in the skin and the identification of a frequent frameshift polymorphism.

Human pancreatic elastase 1 is a serine protease which maps to the chromosomal region 12q13 close to a locus for an autosomal dominant skin disease, diffuse nonepidermolytic palmoplantar keratoderma, and was investigated as a possible candidate gene for this disorder. Expression of two elastase inhibitors, elafin and SLPI, has been related to several hyperproliferative skin conditions. elastase 1 is functionally silent in the human pancreas but elastase 1 expression at the mRNA level was detected in human cultured primary keratinocytes. Antibody staining localized the protein to the basal cell layer of the human epidermis at a number of sites including the palmoplanta. Sequencing of genomic DNA from individuals with/without the keratoderma revealed a sequence variant, which would result in a premature truncation of the protein. This sequence variant, however, did not segregate with the skin disease and, indeed, was found to occur at a relatively high frequency in the population. Individuals homozygous for the variant do not have any obvious skin abnormalities. Based on the analysis of the secondary structure of the translated putative protein, the truncation is unlikely to result in knock-out of the elastase, but may cause destabilization of the enzyme-inhibitor complex.

Amino Acid Sequence↗
PubMed1999

The promoter of a novel human papillomavirus (HPV77) associated with skin cancer displays UV responsiveness, which is mediated through a consensus p53 binding sequence.

An aetiological role has been proposed for human papillomavirus (HPV) in skin carcinogenesis within the immunosuppressed patient population. To examine this possibility, we have focused on an HPV type that, to date, has been identified only in the cutaneous lesions of renal transplant recipients despite a high degree of sequence homology with other HPVs commonly found in warts in the general population. We report that the non-coding region of this virus, HPV type 77, contains a consensus binding site for the tumour suppressor protein p53, and we show by gel-retardation analysis that this sequence does indeed bind p53. Furthermore, using reporter gene assays, we demonstrate that HPV77 promoter activity is stimulated by UV radiation and that this response is mediated through the p53 binding site. This is the first report of a p53-dependent positive response element within a viral genome. Our results suggest a possible novel mechanism by which specific types of HPV might act as cofactors with UV radiation in cutaneous transformation.

Adult↗
PubMed1998

Infection of sheep with adult and larval Ostertagia circumcincta: abomasal morphology.

The infection of parasite-naive sheep with approximately 15,000 adult Ostertagia circumcincta via abomasal cannulae resulted in marked changes in the structure and function of the abomasum. The functional changes, which have been characterised previously, included elevated abomasal pH and increased serum concentrations of pepsinogen and gastrin. Eight days after the transplant of adult worms, the abomasa of recipient animals were significantly heavier than those of controls (P < 0.001), the thickness of the fundic mucosa was greater (P < 0.01), there were fewer parietal cells (P < 0.01) and increases in the numbers of mitotic figures and mucus-producing cells. Mucous cell hyperplasia was also evident in the fundic mucosae of sheep receiving a trickle infection of infective, third-stage O. circumcincta larvae and was prominent within nodules associated with larval development. In non-nodular mucosa, there was hyperplasia of mucous cells and changes in the distribution of parietal cells. Decreases in the number of parietal cells at the gland base were offset by increases at a mid-gland level, probably due to chronic hypergastrinaemia, so that, overall, total parietal cell number was unaffected. Mucous cell hyperplasia and the diminution of parietal cell number are seen in a diverse range of disease states and may be mediated by host growth factors such as Transforming growth factor-alpha. Alternatively, the cellular and/or the secretory changes in response to the presence of adult worms are mediated by chemicals that are cytotoxic/inhibitory for parietal cells, and released by the parasites themselves.

Abomasum↗
PubMed1998

Infection of sheep with adult and larval Ostertagia circumcincta: gastrin.

Gastric endocrine cell populations and serum and tissue gastrin have been examined in sheep which were infected either intraruminally by tube with 150,000 Ostertagia circumcincta larvae followed by a trickle infection of 10,000 larvae thrice weekly for 8 weeks or by the transfer of 15,000 adult worms directly into the abomasum and killed 8 days later. Depletion of both antral gastrin and somatostatin was evident in both groups: tissue gastrin concentrations were reduced by 85% in the trickle infection and both G cells (gastrin-containing) and D cells (somatostatin-containing) were pale and fewer after adult worm transfer. The concurrent depletion of antral gastrin and somatostatin supports the contention that the hypergastrinaemia in parasitised sheep is largely secondary to the increase in abomasal pH. Although there was no change in the proportions of G34 and G17 in the tissues, there was an increase in the longer form of gastrin in the circulation of the larval-infected sheep, suggesting that there may be differential secretion of G17 and G34 which may be exaggerated as the rate of secretion increases. Although the fundic mucosa was thicker following trickle infection, there was no evidence of enterochromaffin-like cell hyperplasia in either infected group. It is suggested that hyper-gastrinaemia may be beneficial to the host, as it may allow the abomasum to regain the ability to acidify its contents during continued exposure to the parasites.

Abomasum↗
PubMed1989

Association between high concentrations of Mr 52,000 cathepsin D and poor prognosis in primary human breast cancer.

The Mr 52,000 cathepsin D is the precursor of a lysosomal protease secreted in excess by breast cancer cells. This protease can degrade extracellular matrices and proteoglycans and is induced by estrogens in estrogen receptor-positive breast cancer cell lines. In a 4- to 6-yr retrospective cohort study, the concentration of the total cathepsin D (precursor plus intermediate and mature chains) was assayed in cytosols of primary tumors from 242 pre/perimenopausal and 154 postmenopausal breast cancer patients in a solid-phase immunoassay using two specific monoclonal antibodies. Patients were initially divided into groups with low, intermediate, or high concentrations of cathepsin D corresponding to the quartiles of the overall distribution. Using these groupings, the level of Mr 52,000 cathepsin D was not significantly associated with the recognized prognostic factors of age, lymph node involvement, tumor size, and/or grade of anaplasia. A significant association was found between cathepsin D concentrations and estrogen receptor status only among pre/perimenopausal patients. Receptor-positive tumors (greater than or equal to 10 fmol of estrogen receptor/mg of cytosol protein) had a significantly greater proportion of patients with high Mr 52,000 cathepsin D concentrations. Patients with high Mr 52,000 cathepsin D concentrations (greater than 78 pmol/mg for pre/perimenopausal and greater than 24 for postmenopausal patients) have shorter recurrence-free survival (P = 0.06 for pre/peri- and P = 0.039 for postmenopausal patients) and have a trend toward shorter overall survival (P = 0.30 and P = 0.089 for pre/peri- and postmenopausal groups, respectively). In multivariate analysis, Mr 52,000 cathepsin D status was found to be an independent prognostic factor for recurrence-free survival of about the same import as lymph node status for both menopausal groups. This first retrospective study demonstrates that the level of Mr 52,000 cathepsin D in cytosol of primary breast cancer biopsies is an independent prognostic factor in predicting relapses in both pre/peri- and postmenopausal patients.

Adult↗
PubMed1988

Immunoenzymatic assay of Mr 52,000 cathepsin D in 182 breast cancer cytosols: low correlation with other prognostic parameters.

The Mr 52,000 cathepsin-D-like protease induced by estrogens in MCF7 human breast cells was assayed in 182 primary breast cancer cytosols prepared for receptor assays from pre- and post-menopausal patients. Using two solid-phase sandwich immunoenzymatic assays, we quantified the total Mr 52,000 cathepsin D (52K-cath-D) (the Mr 52,000 precursor protein and its Mr 48,000 and 34,000 processed forms) and the Mr 52,000 precursor alone. The value of total 52K-cath-D varied between 3 and 165 pmol/mg protein and the proportion of the precursor varied from 0 to 28% of total 52K-cath-D. There was no correlation between the concentrations of 52K-cath-D and estrogen receptor, but the estrogen receptor status (greater than or less than 10 fmol/mg protein) was correlated to the 52K-cath-D status (greater than or less than 15 pmol/mg protein) according to the chi 2 test (P less than 0.001). The correlation with progesterone receptor concentrations and status was low (r = 0.43) and absent, respectively. There was no correlation with Scarff and Bloom stages, tumor size, or patient's age. The percentage of patients with invaded lymph nodes was significantly higher (80%) in the subgroup with the highest total 52K-cath-D levels (greater than or equal to 42 pmol/mg protein), representing only 12% of the population but not in the total population. On the basis of this prospective study, before clinical follow-up can be evaluated, we conclude that in the total population examined, the 52K-cath-D concentration was only correlated with estrogen receptor status, but not with any other prognostic parameter.

Aged↗
PubMed1987

The antiprogestin RU486 in advanced breast cancer: preliminary clinical trial.

Twenty-two oophorectomized or postmenopausal women with metastatic breast cancer resistant to several medical therapies (tamoxifen, or other endocrine therapy, and chemotherapy) were treated in a first trial with 200 mg per day of RU486 for 1 to 3 months. The long-term tolerance was good but there was a moderate decrease in plasma potassium. Plasma cortisol was increased 2-fold without clinical hypo- or hypercorticism. Twelve patients had a partial response or a stabilization of secondary deposits for 6 weeks but the response rate at 3 months was 18%. When available, estrogen and progesterone receptor levels were positive in these patients. This preliminary trial shows for the first time that the antiprogestin RU486 is well tolerated for medium term treatment. It suggests that it might be active on advanced breast cancer becoming resistant to tamoxifen.

Breast Neoplasms↗
PubMed1976

Obstetric complications after treatment of intrauterine synechiae (Asherman's syndrome).

This review comprises 36 patients who were treated for Asherman's syndrome from 1968 to 1974 at the Sloane Hospital for Women. Of the 18 patients who later conceived only 6 had uncomplicated term deliveries. Four had premature deliveries resulting in neonatal death. Three had placenta accreta and postpartum hemorrhage, necessitating a cesarean hysterectomy in 1. Two patients required cesarean section for complications due to the syndrome, 2 had spontaneous abortion, and 1 had a cervical pregnancy requiring total hysterectomy. Only 10 babies survived. The incidence and severity of complications in conceptions following treatment for Asherman's syndrome is high, and the obstetrician must be prepared to manage them.

Abortion, Habitual↗
PubMed1975

The significance of weight loss in the evaluation of pituitary response to LH-RH in women with secondary amenorrhea.

Sixteen women with amenorrhea occurring in the setting of severe self-imposed weight loss and 18 women with secondary amenorrhea due to other causes were given LH-RH (luteinizing hormone-releasing hormone). Women with weight loss were found to be unresponsive to LH-RH when severely underweight. FSH responsiveness returned in a linear fashion as weight gain occurred and was not related to estrogen levels. LH responsiveness also returned with weight gain although the relationship was not linear but exponential and a sudden increase in responsiveness occurred at 15% below ideal weight. No relationship to estrogen levels could be found. Women who experienced amenorrhea in a setting other than weight loss did not demonstrate responsiveness to LH-RH which could be correlated with body mass, even when underweight. Women who experienced amenorrhea with weight loss had a consistently lower LH response to LH-RH than the second group and their LH response was always lower than the FSH response. On the other hand, a variety of patterns was found in women with amenorrhea due to other causes.

Adolescent↗
PubMed1975

The micro-organisms of tsetse flies.

Micro-organisms from tsetse fly mycetomes were maintained in culture, where they were more pleomorphic than in the mycetomes, but were in some cases very similar to those observed in ovaries by other authors. Agglutination tests on the cultured forms indicated in affinity to Rickettsia. They were sensitive to antibiotics introduced by feeding flies on hosts treated with Ampicillin; this reduced the longevity and fecundity of the tsetse flies and appeared to disturb normal digestion of bloodmeals.

Agglutination Tests↗