Biomedical subjects

R K Iles

Publications and source records attributed to R K Iles.

At least 37 records · Page 2Linked to original sources

PubMed1998

The prognostic significance of beta human chorionic gonadotrophin and its metabolites in women with cervical carcinoma.

AIMS: To examine long term survival of women with primary and recurrent cervical carcinoma in relation to (1) excretion of beta-core (a urinary metabolite of beta human chorionic gonadotrophin (beta hCG)) and (2) beta hCG immunostaining of the tumours, to determine the suitability of these markers for assessing prognosis. METHODS: This was a prospective observational study undertaken in a gynaecological oncology centre: 57 women with primary cervical cancer and 42 with recurrent disease were recruited between January 1990 and September 1992. Kaplan-Meier survival analysis with the log rank test was used to assess survival differences with survival rate given per year of follow up. RESULTS: In primary disease, the four year survival for the beta-core negative group was 79%, compared with 14% for the beta-core positive group (p = 0.001). This was still significant for early stage disease or squamous lesions alone. In recurrent disease, beta-core positivity was not prognostically significant. Immunohistochemistry was of no prognostic significance in either group. CONCLUSIONS: beta-core excretion appears to be useful in assessing prognosis of primary cervical cancer but not of recurrent disease. A large prospective study of urinary beta-core in early stage cervical cancer is needed to determine whether it can be used as an index for modifying treatment.

Adenocarcinoma↗

PubMed1998

Dissociation of human chorionic gonadotropin into its free subunits is dependent on naturally occurring molecular structural variation, sample matrix and storage conditions.

Measurement of human chorionic gonadotrophin (hCG) is used in many areas of clinical medicine. Recent interest has focused on the stability of this molecule and its fragments during sample storage. In the body hCG is degraded and removed by specific metabolic processes which begin while the molecule is in the bloodstream. In particular, the receptor binding loop of the beta subunit is cut or 'nicked', initiating a catabolic cascade. Furthermore, the extent and nature of glycosylation is believed to have a significant influence on this process. In these studies we incubated seven glycoforms of hCG, each with different degrees of 'nicking', in phosphate-buffered saline, serum, defibrinated blood and urine from healthy non-pregnant women, under varying conditions. Degradation was expressed as the molar increase in free beta subunit. Under all conditions there was a steady dissociation of hCG over time, the process being more rapid at higher temperatures. 'Nicked' hCG dissociated more rapidly than did non-'nicked' hCG. Glycosylation reduced the rate of dissociation. Dissociation was most rapid in urine and buffer solutions, and slowest in serum and defibrinated blood.

Chorionic Gonadotropin↗

PubMed1998

Measures of urine concentration in maternal urine screening for Down syndrome.

A study was carried out to assess eight methods of normalizing the level of urinary beta-core human chorionic gonadotropin (hCG) for variable urine concentration. We compared the standard approach--creatinine determination by the Jaffe method--with high performance liquid chromatography (HPLC) measurement of creatinine, osmolarity and optical density at five wavelengths. Urine samples were included from a total of 472 women with unaffected singleton pregnancies at 15 weeks' gestation. The median beta-core hCG value was determined for each decile group when the results were ranked in turn according to the different measures of urine concentration. Creatinine using the Jaffe method had a much stronger relationship with median beta-core hCG than the other measures. Linear regression across the decile groups gave an R2 value for Jaffe of 0.85 compared with HPLC of 0.53, osmolarity of 0.52, optical density at 405 nm of 0.72, at 450 nm of 0.57, at 490 nm of 0.33, at 570 nm of 0.34 and at 630 nm of 0.33. We conclude that when screening with urinary beta-core hCG measuring creatinine appears to be an adequate method of allowing for variable urine concentration.

Chorionic Gonadotropin, beta Subunit, Human↗

PubMed1997

Comparison of 12 assays for detecting hCG and related molecules in urine samples from Down syndrome pregnancies.

Urine is a new medium for Down syndrome testing. In an effort to determine the best type of human chorionic gonadotropin (hCG)-related immunoassay for urine testing, we examined 14 Down syndrome and 91 unaffected pregnancy urine samples with 12 established assays. The assays included (a) those that detect hCG beta-core fragment only; (b) those that detect beta-core fragment with less than 18 per cent free beta-subunit cross-reactivity; (c) that which equally detects free beta-subunit and beta-core fragment; and (d) those that detect hCG, free beta-subunit, or combinations thereof. The seven type a and b assays had the highest sensitivity for Down syndrome. The median MOM for Down syndrome was 5.93 (range 4.73-7.53). At a 10 per cent false-positive rate, the median observed detection rate was 93 per cent (range 79-100 per cent) and the median predicted detection rate was 85 per cent (range 69-96 per cent). The assays that did not mainly detect beta-core fragment (types c and d) had poorer screening performance. The median MOM for Down syndrome was 2.70 (range 2.16-3.63 MOM). At a 10 per cent false-positive rate, the median observed detection rate was 50 per cent (range 36-64 per cent) and the median predicted detection rate was 37 per cent (range 21-62 per cent). We infer that the assays that only detect beta-core fragment, or beta-core fragment with minor free beta-subunit cross-reactivity (types a and b), are the better urine-based tests for Down syndrome screening.

Case-Control Studies↗

PubMed1996

Urinary analysis for Down's syndrome: is the measurement of urinary beta-core the future of biochemical screening for Down's syndrome.

Most Down's Screening protocols have concentrated on the analysis of oncofetal antigen levels present in serum. Urine has largely been ignored, but mass screening based on a urine text has several logistical advantages. We have examined the levels of urinary beta-core as a marker of Down's syndrome. (beta-core is a major immunoreactive degradation product of hCG and in particular its beta-subunit). Elevated maternal serum hCG is the single most effective biochemical marker of Down's syndrome and levels are more than doubled. Measurement of elevated free beta-subunit has been shown to be a superior discriminator than measurement of intact or total-hCG. This was shown by an increase in comparative serum levels from 2.04 to 2.41 multiples of the control population medium (MoM). The median MoM value of beta-core for Down's cases in studies has varied between 4.38 and 6.28. The proportion of true Down's cases having a beta-core value greater than the 95th centile of the controls varied from 61 to 93%. This is far superior to any single serum marker. If other complimentary urinary markers can be found urinary screening could replace serum screening not only because of the logistical advantages but increased sensitivity.

Chorionic Gonadotropin, beta Subunit, Human↗

PubMed1996

The effects of beta-human chorionic gonadotrophin on the in vitro growth of bladder cancer cell lines.

The effects of human chorionic gonadotrophin (hCG) and its subunits on in vitro bladder cancer cell growth have been assessed using the a tetrazolium salt reduction assay (MTT). Intact hCG, alpha-hCG and beta-core hCG all had no effect on cell growth, while beta-hCG increased MTT reduction in all four bladder cancer lines tested. The magnitude of beta-hCG stimulation was maximal in the T24 line, which does not itself produce beta-hCG and appeared to be correspondingly lower in beta-hCG-secreting lines. The addition of antibodies to beta-hCG inhibited MTT reduction among high secretors but failed to inhibit MTT reduction in non-beta-hCG producers. These results are consistent with the poor prognosis associated with beta-hCG expression by bladder tumours in vivo and suggest an autocrine/paracrine stimulation of tumour growth by endogenously produced beta-hCG.

Cell Division↗

PubMed1996

Urinary concentration of human chorionic gonadotrophin and its fragments as a prognostic marker in bladder cancer.

OBJECTIVE: To examine the prognostic significance of elevated urinary beta human chorionic gonadotrophin (beta-hCG) in patients with bladder cancer. PATIENTS AND METHODS: Total beta-hCG was measured in the urine of 142 patients referred for cystoscopic examination. Patients were followed for a minimum of 17 months and grouped according to stage of disease. Because the water output by individual patients varied, urinary creatinine levels were measured as an indicator of the concentration of the urine sample. Patient outcomes were correlated with urinary total beta-hCG levels both corrected and uncorrected for creatinine concentration. After correcting for urinary creatinine levels, 40 patients were excluded because the sample was too dilute (undetectable beta-hCG and a creatinine level of < 4 mmol/L). A further four patients were excluded as they had concurrent malignancies not in the bladder and one patient was lost to follow up. RESULTS: None of the 52 patients with benign conditions, nine of the 27 with Ta-T1, and nine of the 25 with T2-T4 bladder disease had urinary total beta-hCG levels > 3.74 IU/mmol/L creatinine. There was no significant association between urinary total beta-hCG concentrations and the rates of recurrence or progression for Ta-T1 disease at 17 months of follow-up. For patients with T2-T4 disease there was a significant association with widespread metastasis (P < 0.01) and mortality (P < 0.01) at 17 months of follow-up. These associations persisted when urinary total beta-hCG levels were not corrected for urinary creatinine concentration (metastasis, P < 0.01; mortality, P = 0.07; Kaplan-Meier survival time analysis, uncorrected for creatinine P = 0.027, corrected for creatinine P < 0.001). This association could not be accounted for by differences in age, histopathology or treatment. CONCLUSION: Although sample concentration was a serious confounding factor, after correcting for dilution using the creatinine content, the elevated urinary levels of total beta-hCG indicated those T2-T4 lesions which were likely to metastasize and those patients likely to die early. If this test is to be used clinically, concentrated samples, i.e. early-morning urine, and a more sensitive beta-hCG assay are required. Nevertheless, for T2-T4 bladder tumours, an elevated pre-treatment level of urinary beta-hCG is a marker of poor prognosis and may prove useful in deciding appropriate therapy.

Aged↗

PubMed1996

The temporary anatomical structures prominent in the first trimester may be fulfilling exchange functions assigned to the placenta in the second and third trimester.

The extra-embryonic coelom (EEC) and secondary yolk sac are prominent structures in the gestational sac during the first trimester of human pregnancy, at a time before the definitive placental circulation becomes established. We propose that the EEC and yolk sac play a critical role in the nutrition of early pregnancy, fulfilling exchange functions which are assumed by the placenta at a later stage.

Amniotic Fluid↗

PubMed1995

Urinary multiple marker screening for Down's syndrome.

We have examined the possibility of using multiple markers in maternal urine rather than serum in order to screen for Down's syndrome. Urine samples were available from 36 cases (24 Down's syndrome, five Edwards' syndrome, three Turner's syndrome, one Klinefelter's syndrome, one triploidy, one triple-X, one twin discordant for Down's syndrome) and 294 controls, including three twins. Three markers were tested: the beta-core fragment of human chorionic gonadotrophin (hCG), total oestrogen (tE) and the free alpha subunit of hCG. Levels were corrected for creatinine excretion and expressed as multiples of the gestation-specific median (MOM) level from the singleton controls. The median value for the singleton Down's syndrome cases was 6.02, 0.74, and 1.08 MOM for beta-core-hCG, tE, and alpha-hCG, respectively. The increases in beta-core-hCG and the reduction in tE levels were highly significant (P < 0.0001 and 0.005, respectively; Wilcoxon rank sum test) but the increase in free alpha-hCG was not (P = 0.40). On the basis of a mathematical model, the expected detection rate for a 5 per cent false-positive rate was 79.6 per cent for beta-core-hCG alone, which increased to 82.3 per cent when combined with tE. Aneuploidies other than Down's syndrome were characterized by low levels of tE and either low or high beta-core-hCG.

Adult↗

PubMed1995

Measurement of urinary beta core fragment of human chorionic gonadotrophin in women with vulvovaginal malignancy and its prognostic significance.

Tumours of the vulva and vagina are rare and there are relatively few studies of circulating markers in these conditions. The urinary measurement of the core fragment of the beta-subunit of hCG has been proposed as a useful tumour marker in non-trophoblastic gynaecological malignancies. This study describe the measurement of urinary beta-core in 50 patients with vulvovaginal malignancy. In contrast to other studies corrections were made for both the effect of urine concentration and the age of the patient. Each patient was followed up for at least 24 months, and at this time their status was correlated with their initial level of urinary beta-core. The sensitivity of beta-core was only 38%, but of those patients with elevated levels 90% had died within 24 months, while only 32% of those with normal levels had died. For both patients at initial presentation and those with recurrent disease, there was a highly significant difference in the survival curve between those with elevated beta-core levels and those with normal levels. This is similar to findings in cervical carcinoma, and suggests that for lower genital tract cancer the measurement of urinary beta-core may be valuable as a prognostic indicator, allowing a more informed approach to treatment and follow-up.

Adult↗

PubMed1995

The role of glycosylation in regulating the glycoprotein hormone free alpha-subunit and free beta-subunit combination in the extraembryonic coelomic fluid of early pregnancy.

The extraembryonic coelomic fluid (EECF) represents a major compartment in the fetal-placental unit during the first trimester of pregnancy. The compartment is composed of the fluid contained between the chorionic and amniotic membranes. The levels of glycoprotein hormone free alpha-subunit and free beta-subunit in the EECF far exceed those in the amniotic fluid or maternal serum. Furthermore, the level of free alpha in this compartment is twice that of intact hCG. We purified the glycoprotein hormone free alpha-subunit from a pool of EECF. This free alpha-subunit was found to be larger in size than the alpha-subunit of intact hCG. The size difference was observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reduced and denatured conditions. The carbohydrate composition of the EECF free alpha-subunit indicated a higher degree of oligosaccharide branching, as evidenced by larger amounts of fucose, sialic acid, galactose, and N-acetylglucosamine than were present on combined hCG alpha. These differences in size and carbohydrate composition argue strongly against the concept that free alpha-subunits might originate from dissociation of intact hCG or "nicked" hCG. The free subunits of the EECF were evaluated for their ability to combine with the corresponding subunit obtained by dissociation of intact hCG. EECF free beta was able to combine with hCG alpha to form intact hCG. In contrast, EECF free alpha was unable to combine with hCG beta to form intact hCG. However, after removal of the asparagine-linked glycans by treatment with N-glycanase, most of the previously uncombinable free alpha-subunits were able to combine with hCG beta. These data demonstrate that the N-linked oligosaccharide(s) of EECF free alpha function to prevent the molecule from combining with the available and combinable free beta-sub-units that coexist in the same physiological compartment during early pregnancy. In view of the large amount of free alpha that is present in the EECF and the observation that, in vitro, free alpha can stimulate uterine decidual cell PRL secretion, together with the close apposition of free alpha-producing cells to decidual cells, it is likely that EECF free alpha has a function in early pregnancy. Carbohydrate modifications generated during the biosynthesis of EECF free alpha-subunit ensure that a population of free alpha molecules can exist in the presence of substantial quantities of free beta-subunits, and correspondingly, these same carbohydrate modifications function to permit the existence of free beta-subunits in the same gestational compartment with free alpha molecules.(ABSTRACT TRUNCATED AT 400 WORDS)

Amniotic Fluid↗

PubMed1994

Second trimester amniotic fluid placental alkaline phosphatase levels are low in Down's syndrome but not in other fetal abnormalities.

Second trimester amniotic fluid placental alkaline phosphatase (PLAP) immunoreactivity was measured in 756 normal pregnancies, 63 Down's syndrome pregnancies and 42 pregnancies associated with other chromosomal abnormalities. PLAP levels were significantly reduced in cases of Down's syndrome (MoM = 0.72, U = 17,565, P = 0.0002, 95% Cl = 0.63-0.88). However, there was no significant difference between other aneuploid conditions and the normals (MoM = 0.88, U = 13,289, P = 0.35, 95% CI = 0.77-1.08). PLAP is the carrier protein for immunoglobulin G. Neonates with Downs syndrome but not other chromosomal abnormalities are associated with a deficiency of IgG. These data therefore support the theory that the low IgG levels in Downs syndrome are a result of a defect in PLAP transport.

Alkaline Phosphatase↗

PubMed1994

Urinary beta-core human chorionic gonadotrophin: a new approach to Down's syndrome screening.

Human chorionic gonadotrophin (hCG) is the most discriminatory maternal serum marker of Down's syndrome. We have carried out a study to establish whether urinary beta-core-hCG, a major metabolic product of hCG, might be an even better marker. Urine samples were available from seven singleton pregnancies with Down's syndrome, and one each of Edwards' syndrome, triploidy, and twins discordant for Down's syndrome. beta-Core-hCG levels were corrected for creatinine and expressed as multiples of the normal gestation-specific median (MOM) level derived from 67 singleton controls. There was a highly statistically significant elevation in level among the singleton Down's syndrome cases (P < 0.0005; Wilcoxon rank sum test). All had levels exceeding 2 MOM with a median of 6.11 MOM (95 per cent confidence interval 3.7-10.0). The levels were extremely low in Edwards' syndrome (0.08 MOM) and triploidy (0.02 MOM), but the twin pregnancy discordant for Down's syndrome did not have a raised beta-core-hCG level (0.64 MOM). The findings are sufficiently encouraging to investigate the possibility of urinalysis as a routine modality in the prenatal screening for Down's syndrome and other common serious aneuploidies.

Adolescent↗

PubMed1994

The prognostic significance of urinary beta core fragment in premenopausal women with carcinoma of the cervix.

The mortality of premenopausal women with cervical carcinoma has increased in recent decades despite attempts to provide screening. The urinary concentration of the beta core fragment of hCG has been proposed as a sensitive marker in gynecological malignancies, although most studies have not corrected for urine concentration. We measured the urinary concentration of beta core and creatinine in 61 women who developed cervical cancer premenopausally and expressed the concentration of beta core per millimole of creatinine using the 90th percentile of a control group as a cutoff level. While correcting for urinary concentration results in a reduction in sensitivity of the test (67 to 51%), there is improved correlation with prognosis in that after 18 months 81% of women positive for beta core had died, while 80% of women negative for beta core were still alive. Of those initially presenting and dying there was an increase with increasing stage of disease. For patients with initial presentation disease, 11 (79%) of the 14 patients with elevated levels had died compared with 1 of 21 (5%) who were negative for beta core. Urinary beta core fragment may have a major role as a prognostic indicator in cervical carcinoma rather than as a screening or diagnostic marker and enables identification of patients at higher risk of an aggressive disease.

Biomarkers, Tumor↗

PubMed1994

Pregnancy-associated plasma protein A levels in maternal serum, extraembryonic coelomic and amniotic fluids in the first trimester.

First trimester maternal serum levels of pregnancy-associated plasma protein A(PAPP-P) are reduced in women with a Down's syndrome pregnancy. We have examined the concentration of this molecule in the amniotic (AF) and extra-embryonic coelomic (EECF) fluids surrounding the developing fetus. Maternal serum levels of PAPP-A were elevated in all samples and steadily rose from a median of 480 mIU/1 at 8 weeks to a median of 6375 mIU/1 at 14 weeks gestation. Levels of PAPP-A were low in EECF and undetectable in the AF until 14 weeks gestation. This pattern of distribution is in contrast to that of most other trophoblast-associated antigens. This may reflect PAPP-A physiology and its specific production by the syncytiotrophoblast.

Amniotic Fluid↗

PubMed1994

Low levels of amniotic fluid pregnancy specific beta-1-glycoprotein in Down's syndrome.

Amniotic fluid levels of beta-1-glycoprotein (SP1) were measured in 46 cases of Down's syndrome and compared with levels in 106 pregnancies of normal karyotype from 10 to 23 weeks of gestation. In normal pregnancies, levels rose from 87.5 iu/l at 10 weeks to a peak of 610.0 iu/l at 19 weeks of gestation. In cases of Down's syndrome, levels were reduced prior to 19 weeks of gestation (median multiple of the median, MoM = 0.75, P = 0.02). This effect was most marked prior to 16 weeks of gestation when the median multiple of the median (MoM) was 0.51 (P = 0.006). These data demonstrate that amniotic fluid levels of SP1 are low in Down's syndrome before 19 weeks of gestation.

Amniotic Fluid↗

PubMed1994

Characterisation of the differential expression of marker antigens by normal and malignant endometrial epithelium.

In order to examine the production of marker proteins, a reproducible method has been established for culturing purified epithelial cells from normal and malignant endometrium. We have examined the differential expression of secretory proteins using immunohistochemistry in frozen tissue sections, immunocytochemistry in cell cultures derived from the same specimens and protein assays on the culture supernatants. Placental protein 14 (PP14) was produced by normal premenopausal epithelium but not by the post-menopausal or malignant endometrial epithelium. In contrast, placental alkaline phosphatase (PLAP) was produced by endometrial cancers and the endometrial adenocarcinoma-derived cell line Ishikawa, but not by the normal endometrial epithelium. Other markers such as CA-125, which was produced by both normal and malignant endometrium but not by the cell line, and human chorionic gonadotrophin (beta-hCG), which was produced by Ishikawa cells but not by any of the fresh tissues, were less cancer specific. Placental alkaline phosphatase is a direct product of endometrial cancers that can be readily assayed in serum using this two-site assay to test its clinical usefulness in monitoring patients at risk for endometrial cancer.

Adenocarcinoma↗

PubMed1994

Production of placental alkaline phosphatase (PLAP) and PLAP-like material by epithelial germ cell and non-germ cell tumours in vitro.

Placental and placental-like alkaline phosphatase (PLAP) levels in the culture media of 87 cell lines of neoplastic and 'normal' origin were measured by a conventional immunosorbent enzymatic assay (IAEA) and by a new immunoradiometric assay (IRMA). The IRMA detected immunoreactive PLAP in 37 of 80 (46%) human epithelial and germ cell cultures, while the IAEA detected PLAP in only 25 (33%). Of the 52 non-germ cell tumour cultures, the IRMA detected expression in 24 (46%) and the IAEA in only 16 (31%). In 17 cases (21%) the IRMA recorded levels double that of the IAEA, while in five cultures (6%) the reverse was true. The IRMA was much more robust than the IAEA and had considerably lower inter- and intra-assay coefficients of variation (3.75-8.5% vs 5.2-46%). Detection of PLAP(-like) expression by IAEA is dependent on neoplastic expression of enzymatically functional molecules and quantification assumes constant enzyme kinetics. PLAP-like material has a higher catalytic rate constant than PLAP and thus will give higher values on a stoichiometric basis in an IAEA. The higher detection rate and levels of PLAP-like material in neoplastic cultures when measured by the IRMA clearly demonstrate ectopic expression of non-enzymatic PLAP and PLAP-like genes. The incidence of PLAP(-like) expression by non-germ cell and possible germ cell tumours has been underestimated and its utility as a tumour marker should be re-examined using assays which measure antigen mass rather than phosphatase activity.

Alkaline Phosphatase↗