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Biomedical subjects

M L Wilkinson

Publications and source records attributed to M L Wilkinson.

At least 55 records · Page 3Linked to original sources
PubMed1989

The relationship between HLA-DR3 and T-cell regulation of immunoglobulin production in primary sclerosing cholangitis.

Immunoglobulin production in vitro, its control by concanavalin A-activated suppressor T-cells, and the relationship between abnormalities in nonantigen-specific suppression and histocompatibility antigens have been studied in 20 patients with primary sclerosing cholangitis (PSC). Suppression of IgG, IgM, and IgA synthesis was impaired in 12 patients with PSC alone, but was normal in 8 with PSC and associated ulcerative colitis (UC). The HLA antigens B8 and DR3 were increased in frequency in both groups of patients, but an association between DR3, and to a lesser extent B8, and defective suppressor T-cell function was only observed in the patients with PSC alone. These results not only provide further evidence of an association between HLA DR3 and impaired nonantigen-specific suppression but also indicate the genetic complexity of this association and its specificity, being found in this study in only one subgroup of patients with PSC.

Adult↗
PubMed1987

Interactions of foetal steroid binding protein with other binding proteins in human serum.

Foetal steroid binding protein (FSBP) which is present in normal human serum sometimes exhibits unusual sex-steroid binding; its effects on steroid action are uncertain but potentially important in view of the different levels seen in populations at different risk of breast cancer. Studies of the binding of 5 alpha-dihydrotestosterone to FSBP were conducted at varying concentrations of human serum albumin (HSA) and sex hormone binding globulin (SHBG). The saturable, specific binding of purified FSBP (Ka approximately equal to 5 X 10(8) l/mol), was transformed to a rising, plateau pattern by the addition of HSA. In equilibrium dialysis, FSBP competed with HSA or SHBG in a strictly proportional way when the third protein was absent. In the presence of HSA an initial sharp shift of ligand from SHBG to FSBP was observed with increasing FSBP concentration, but this was reversed as higher levels were reached. Steroid binding by FSBP in vivo may be determined predominantly by its interactions with other binding proteins.

Blood Proteins↗
PubMed1987

Response to cyproterone acetate treatment in primary hepatocellular carcinoma is related to fall in free 5 alpha-dihydrotestosterone.

The male preponderance in cirrhotic patients with primary hepatocellular carcinoma (HCC) and the presence of androgen receptors in tumour tissue suggest possible benefit from anti-androgenic therapy. Twenty-five cirrhotic patients with irresectable HCC (23 male) were treated with cyproterone acetate (CPA) 300 mg daily. Hepatic ultrasound, alpha-fetoprotein and total and free sex steroid levels were monitored. Five patients had an objective response to therapy with a median duration of 8 weeks and survival in excess of 29 weeks. Median survival for all patients was 14 weeks. Apart from transient paranoia in two cases, side-effects were minimal. Total androgen levels (measured in 13 patients) had fallen significantly at 10 weeks, but free 5 alpha-dihydrotestosterone (DHT) which had fallen by 4.8 pM (median) in five responders, had risen by 5.05 pM in eight non-responders: P less than 0.025. The apparent correlation of response with reduction in free DHT suggests that hormonal manipulation may be effective in HCC if free DHT is reliably reduced. This has been achieved in other conditions by the combination of CPA with low dose oestrogen or with LHRH agonists.

Adult↗
PubMed1987

Primary sclerosing cholangitis in childhood.

Thirteen children (8 female) with primary sclerosing cholangitis are described, in whom the diagnosis was confirmed by the presence of characteristic changes on endoscopic retrograde cholangiopancreatography. Nine had clinical features of chronic inflammatory bowel disease 1 mo to 5 yr before the onset of primary sclerosing cholangitis (6 patients) or appearing simultaneously with primary sclerosing cholangitis (3 patients). In 4 patients clinical evidence of chronic inflammatory bowel disease was absent but 1 of the 4 was found to have microscopic colitis in colonoscopic biopsy specimens. Biopsies were not performed in the remaining 3 patients. High immunoglobulin G concentrations and positive antinuclear or smooth muscle antibodies were present in all patients except 1 who had been given immunosuppressants. In 7 patients treated with immunosuppressants and followed up for 9 mo to 10 yr there was modest symptomatic improvement. This improvement was accompanied by a fall in transaminase levels in 6 of the patients and histologic improvement in 3 of 4 patients who had undergone biopsy. Greater use of endoscopic retrograde cholangiopancreatography in the last 6 yr led to the identification of 10 of these 13 cases, suggesting a higher incidence of primary sclerosing cholangitis in childhood than would appear from the literature.

Adolescent↗
PubMed1987

Foetal steroid binding protein in British and Japanese women.

In order to examine the newly-discovered sex-steroid binding protein, foetal steroid binding protein (FSBP) in different populations, its binding characteristics and its level were studied by two-tier column ligand binding assay and enzyme-linked immunosorbent assay (ELISA) respectively. In 10 Japanese premenopausal women, analysis of 5 alpha-dihydrotestosterone (DHT) binding in the Cibacron Blue 3GA-Sepharose 6B portion of the column showed a rising plateau pattern with a mean maximum binding of 31.1 +/- 7.41%, whereas of 9 similar British women, 8 displayed unsaturable, non-cooperative binding of 11.6 +/- 8.22% (P less than 0.01). After partial purification of FSBP in these samples, the protein exhibited saturable binding kinetics, median binding 25 (interquartiles 23-34) and 19 (13-25) nmol DHT/l in Japanese and British women, respectively (P less than 0.05). By analyzing FSBP by ELISA in 56 Japanese (45 premenopausal) and 59 British (25 premenopausal) women, higher levels were obtained in the whole Japanese group (P = 0.0016) and in the premenopausal Japanese women (P = 0.018) than in their British counterparts. In both nationalities, FSBP levels were higher in premenopausal women, and there was a significant negative correlation of FSBP with age in both populations, particularly in postmenopausal women. FSBP levels did not correlate with weight, parity, sex hormone binding globulin or albumin levels. The influence of FSBP on free steroid levels remains unclear, but some relationship with ovarian function seems a possibility.

Adult↗
PubMed1986

Purification of foetal steroid-binding protein from human serum by affinity chromatography on 5 alpha-androstane-3 beta,17 beta-diol 3-hemisuccinate-aminohexyl-Sepharose 6B.

In order to develop an immunoassay for foetal steroid-binding protein in human serum, which is impossible to assay quantitatively in normal samples by conventional ligand-binding techniques, the protein was purified by salt precipitation, affinity chromatography and gel filtration. Elution was by competing ligand or alkaline pH. The purified protein was further characterized and a highly specific antiserum was raised in rabbits.

Androstane-3,17-diol↗
PubMed1986

Androgen receptor in human normal and malignant pancreatic tissue and cell lines.

Estrogen and progestogen receptors have been demonstrated in human pancreatic adenocarcinoma tissue. Tumor growth as xenografts in nude mice is promoted by testosterone and retarded by cyproterone acetate but is not influenced by estrogens, progestogens, or their antagonists, although estrogen receptors were demonstrated in xenograft cytosol. A new sensitive microassay technique for sex steroid receptors which relies on affinity chromatography was used in this study. With this assay, androgen receptors were detected in five fresh human pancreatic adenocarcinoma specimens (three male), two pancreatic cancer cell lines (Mia PaCa 2 and Ger), one xenograft tumor which responded to androgens, five specimens of normal adult pancreas (two male), and a pool of fetal pancreatic tissue. The similarity of the androgen receptor in pancreatic carcinoma to that of classical androgen target organs was demonstrated by sedimentation behavior and competitive binding studies. The improved sensitivity of the microassay allowed low levels of estrogen, androgen, and progesterone receptors to be detected in normal adult pancreatic tissue.

Adenocarcinoma↗
PubMed1986

Preponderance of serum and intra-hepatic 5 alpha-dihydrotestosterone in males with hepatocellular carcinoma despite low circulating androgen levels.

To investigate possible influences of the sex-steroid milieu on hepatocellular carcinoma (HCC) and vice versa, circulating and intra-hepatic sex-steroid levels were investigated and compared with the levels in cirrhosis alone. In cirrhotic men with HCC, serum 17 beta-oestradiol levels were normal, unlike the elevated levels in men with cirrhosis alone. Total and free levels of testosterone and 5 alpha-dihydrotestosterone (DHT) were lower in patients with HCC than in cirrhotic or normal men; the greater decrease in testosterone levels caused an elevated DHT: testosterone ratio. Hypothalamic-pituitary axis dysfunction demonstrated for HCC and cirrhotic groups could not explain the differences in sex-steroids between them. Compared with normal tissue, HCC cytosol had lower testosterone and similar DHT levels; both androgens were higher than in cirrhotic tissue, and the intracellular DHT: testosterone ratio in the tumour was much higher than in control tissue. Results suggest alterations in sex-steroid metabolism in HCC favouring hepatic accumulation of 5 alpha-reduced metabolites aided by the elevated intracellular sex-hormone binding globulin levels shown in HCC tissue.

Aged↗
PubMed1985

Characterisation of high affinity binding sites of androgens in primary hepatocellular carcinoma.

The reported presence of androgen receptors (AR) in hepatocellular carcinoma (HCC) and foetal liver, but not in normal adult human liver, has been followed by further study of AR employing a new microassay. Tissues examined were: 5 samples of HCC with surrounding normal liver in 3 cases; 5 samples of cirrhotic liver and a single specimen of HCC in a child. High affinity binding of 5 alpha-dihydrotestosterone (DHT) was detected in cytosol (11.5-21 fmol/mg, Kd 1.5 X 10(-10)-3.1 X 10(-11) mol/l) and in nucleosol (8.7-11.4 fmol/mg, 6.7-1.4 X 10(-11) mol/l) of the 5 HCC samples. All other liver samples exhibited non-specific binding only. Competition studies indicated that DHT, testosterone, androstenedione, 5 alpha-androstan-3 beta, 17 beta-diol, androst-5-ene-3 beta,17 beta-diol and cyproterone acetate were acting at the same receptor binding site, relative displacement of 3H-DHT being 100, 85.7, 77.4, 67.8, 34.5 and 60.2 per cent respectively. Presence of 3.5S cytosolic and both 2.8S and 4S nucleosolic receptor patterns were demonstrated in both prostatic and HCC tissue. These studies confirm the presence of a cytosolic and nucleosolic androgen receptor in HCC which possesses similar characteristics to the AR of human prostate.

Adult↗
PubMed1985

A microassay for the determination of binding parameters of estrogen and androgen receptors employing affinity immobilization on Cibacron blue 3GA-Sepharose 6B.

The problems of currently available ligand-binding assays for sex-steroid receptor proteins include the relatively large mass of tissue required, the interference by sex hormone-binding globulin (SHBG), and use in the androgen receptor (AR) assay of the unstable synthetic ligand methyltrienolone. To overcome these difficulties the stabilizing effect of the dye Cibacron blue 3GA on AR and estrogen receptor (ER) proteins, and its ability to bind to these proteins, was utilized in developing an assay system for each receptor that could be applied to small samples. Use of the affinity gel Cibacron blue 3GA-Sepharose 6B (Blue gel) for the immobilization of AR, ER, and the steroid ligands bound to these receptors in the standard two-tier column assay system enabled the use of a 1:100 (original tissue weight:volume) concentration, making possible full (5-7 point) Scatchard analysis on tissue specimens of a mass as low as 15-20 mg. Significant stabilization of AR and ER was observed and association constants for these receptors were of a similar order of magnitude to those obtained either by Sephadex LH-20 gel filtration or the dextran-coated charcoal adsorption technique. Inactivation by dilution was shown to be largely prevented based on results obtained with cytosol concentrations from 1:5 to 1:100 (original tissue weight:volume). Because Blue gel does not bind SHBG, the natural steroid 5 alpha-androstan-17 beta-ol-3-one (DHT) may be employed as a ligand in the AR assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Adsorption↗
PubMed1985

An enzyme-linked immunosorbent assay for fetal steroid binding protein of human serum.

The binding characteristics and quantitation of the recently reported fetal steroid binding protein (FSBP) cannot be determined on unpurified samples; an immunoassay was therefore desirable. The protein was purified to homogeneity in order to raise a highly specific polyclonal antibody. An enzyme-linked immunosorbent assay applicable to unpurified samples was developed. Intra- and inter-assay coefficients of variation are 8.0% and 9.2% respectively; there is a sensitivity of 30 fmol FSBP per well, and there is no cross-reactivity with other binding proteins. Results obtained with the assay correlate with the more complex ligand binding assay (r = 0.85; p less than 0.02). Measurement of sera showed that FSBP levels are higher in women than in men (51.2 +/- 10.62 nM; 41.2 +/- 13.65 respectively; p less than 0.05) and are elevated in cirrhotic women (66.4 +/- 18.67; p less than 0.05) and in males with hepatocellular carcinoma (62.2 +/- 13.05; p less than 0.002). Use of the enzyme-linked immunosorbent assay confirmed the identity of FSBP separate from sex hormone binding globulin.

Carcinoma, Hepatocellular↗
PubMed1984

Sex steroid binding patterns in primary biliary cirrhosis complicated by hepatocellular carcinoma.

Owing to recent findings of certain unusual sex steroid binding in liver disease--particularly an allosteric biphasic pattern (pattern A) unique to the serum of patients with hepatocellular carcinoma--the serum binding characteristics for 5 alpha-dihydrotestosterone were examined in serum samples from six patients with primary biliary cirrhosis who had developed hepatocellular carcinoma. In all serum samples taken after the development of tumour pattern A binding only was obtained, and in four cases in which earlier samples were also examined there was a transformation from the normal, non-specific binding pattern, or an allosteric plateau pattern seen in non-malignant liver disease (designated D and C respectively), to pattern A coincident with the rise in serum alpha fetoprotein. In one patient chemotherapy leading to a fall in alpha fetoprotein abolished pattern A binding, showing further its close association with tumour growth. The value of pattern A binding as a tumour marker in hepatocellular carcinoma warrants further study.

Aged↗
PubMed1984

Hepatocellular carcinoma in the non-cirrhotic liver: a comparison with that complicating cirrhosis.

The clinicopathological features of 50 patients with hepatocellular carcinoma arising in a non-cirrhotic liver are described and compared with those of 100 patients in whom the tumour arose as a complication of cirrhosis. The non-cirrhotic patients were significantly younger, more often female and had a less strong association with serum markers of hepatitis B virus infection. Liver function tests and serum AFP were less often abnormal and survival was significantly better than in the cirrhotic group. The different aetiological factors, clinical features and prognosis of hepatocellular carcinoma arising in the non-cirrhotic liver compared to the more common form of hepatocellular carcinoma which complicates cirrhosis justifies detailed investigation by liver biopsy and other techniques.

Adolescent↗
PubMed1983

Sex steroid receptor proteins in foetal, adult and malignant human liver tissue.

Sex steroid receptor proteins were studied in human normal liver and hepatocellular carcinoma (HCC). Oestrogen receptor (ER) was detected in nucleosol and cytosol of 4 normal adult and 5 malignant liver specimens and in the cytosol of 6 foetal liver samples. Levels were 27.6-500 fmol mg-1 soluble protein in normal adults (Kd 1.48 X 10(-8) -1.12 X 10(-10) mol 1(-1) ), 45-290 fmol mg-1 in malignant liver tissue (Kd 3.26 X 10(-9) -3.64 X 10(-10) mol 1(-1] and a mean of 93 fmol mg-1 in foetal tissue (Kd 1.55 X 10(-9) mol 1(-1]. Androgen receptors (AR) were found only in cytosol and nucleosol of HCC (23-370 fmol mg-1) and in cytosol from foetal liver (29 fmol mg-1) with Kd from 2.90 X 10(-9) to 3.734 X 10(-10) mol 1(-1]. AR was distinguished from sex hormone binding globulin, which was also present in all cytosol samples, by the former's ability to selectively bind to methyltrienolone and the latter's absence from nucleosol. These findings provide further support for suggestions that oestrogen-related hepatic functions in man may be mediated by receptors and raise the possibility that hepatocellular carcinoma may be androgen dependent.

Adolescent↗
PubMed1983

Sex-steroid enzymes, aromatase and 5 alpha-reductase in the pancreas: a comparison of normal adult, foetal and malignant tissue.

1. Following the finding of high levels of oestrogen receptor proteins in pancreatic carcinoma tissue, two enzymes involved in sex-steroid biosynthetic pathways, aromatase and 5 alpha-reductase, have been measured. 2. Activities of aromatase, which converts testosterone into oestradiol, comparable with those found in pre-menopausal uterus (P less than 0.5) were found in all seven samples of pancreatic carcinoma tissue, and in a pooled sample of foetal pancreas. Measurable but significantly lower activities (P less than 0.001) of aromatase were found in seven specimens of normal pancreas. 3. 5 alpha-Reductase activity, which converts testosterone into the more potent androgen 5 alpha-dihydrotestosterone, was found in malignant pancreatic tissue at approximately half the level found in prostatic tissue (P less than 0.01) and at almost twice the levels found in either normal adult or pooled foetal pancreatic tissue (P less than 0.01). 4. These findings suggest that sex steroids are involved in foetal and adult pancreatic physiology. 5. Since these enzyme pathways are present in pancreatic carcinoma at greater levels than those in normal adult pancreas, it is possible that agents known to interfere with steroid metabolism could be of value in the treatment of this tumour.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1983

Wilson's disease and hepatocellular carcinoma: possible protective role of copper.

A male patient with Wilson's disease developed a hepatocellular carcinoma after treatment for nine years with D-penicillamine. Examination at necropsy showed that excess liver copper had been effectively removed. As copper has been shown to protect against chemically induced hepatocellular carcinoma in rats, this may be the reason for the extreme rarity of hepatocellular carcinoma in patients with Wilson's disease and possibly in other liver diseases with hepatic copper overload.

Adult↗