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J A Bell

Publications and source records attributed to J A Bell.

At least 73 records · Page 4Linked to original sources
PubMed1995

Assessment of the new proliferation marker MIB1 in breast carcinoma using image analysis: associations with other prognostic factors and survival.

The 'growth fraction' of tumours can now be assessed on paraffin sections of tissues using the monoclonal antibody MIB1 by a microwave antigen retrieval technique. The MIB1 labelling index was studied using a CAS 200 image analyser in 177 tumours from women with primary operable breast carcinoma in whom long-term follow-up data were known. Statistical analysis showed a strong association between the MIB1 labelling index and histological grade (P < 0.001), tumour size (P = 0.002), tumour type (P < 0.001) and also patient survival (P < 0.001). No association with lymph node stage (P = 0.974) or regional recurrence (P = 0.185), the presence or absence of distant metastases (P = 0.418), patient age (P = 0.309), menopausal status (P = 0.181) or oestrogen receptor status (P = 0.401) was found in this group of patients. In multivariate analysis for survival, when histological grade, lymph node stage and tumour size were included as well as the MIB1 labelling index, each was found to be of independent significance. If histological grade was not included, MIB1 replaced it as the most important variable predicting for survival in this group of patients. The results suggest that the tumour growth fraction, as assessed by the MIB1 labelling index, is an important predictor of survival.

Antibodies, Monoclonal↗
PubMed1995

Metallothionein expression in human breast cancer.

Metallothioneins are ubiquitous low molecular weight proteins characterised by high cysteine content and affinity for binding heavy metals. Abnormal metallothionein function and expression have been implicated in various disease states, including neoplasia. The aim of this study was to investigate metallothionein expression in human breast carcinoma. Sections of routinely fixed and processed blocks of tumour from 100 consecutive cases of primary operable breast carcinoma were stained for metallothionein using a recently developed monoclonal antibody and a standard immunohistochemical technique. Expression was scored on the basis of microscopical assessment of percentage of tumour cells staining. One patient was lost to follow-up and excluded from the study. A significant association (P < 0.0001) was observed between metallothionein expression and tumour type, with low levels being observed in tumours of good prognostic type. There was also a significant association with local recurrence (P < 0.02) and a significant difference (P < 0.02) in both survival and disease-free interval between tumours showing low and high levels of expression, the latter indicating a poor prognosis. No relationship was observed with patient age, tumour size, lymph node stage, histological grade, vascular invasion, menopausal status or oestrogen receptor status. The assessment of metallothionein expression in human breast cancer appears to provide prognostic information and may have important implications for understanding its development.

Breast Neoplasms↗
PubMed1995

Immunoaffinity purification and comparison of allantoinases from soybean root nodules and cotyledons.

Allantoinase (allantoin amidohydrolase, EC 3.5.2.5) catalyzes the conversion of allantoin to allantoic acid in the final step of ureide biogenesis. We have purified allantoinase more than 4000-fold by immunoaffinity chromatography from root nodules and cotyledons of soybean (Glycine max [L] Merr.). We characterized and compared properties of the enzyme from the two sources. Seed and nodule allantoinases had 80% identity in the first 24 amino acid residues of the N terminus. Two-dimensional gel electrophoresis of the purified enzymes showed that multiple forms were present in each. Allantoinases from nodules and cotyledons had very low affinity for allantoin with a Km for allantoin of 17.3 mM in cotyledons and 24.4 mM in nodules. Both had activity in a broad range of pH values from 6.5 to 7.5. In addition, purified allantoinase from both sources was very heat stable. Enzyme activity was stable after 1 h at 70 degrees C, decreased gradually with heating to 85 degrees C, and was lost at 90 to 95 degrees C. Although these studies have revealed some differences between allantoinases in seeds and nodules, the differences were not reflected in key enzyme properties. The immunoaffinity approach enabled purification of allantoinase from soybean root nodules and simplified its purification from cotyledons, thereby allowing characterization and comparison of the enzyme from the two sources.

Amidohydrolases↗
PubMed1995

The assessment of multiple variables on breast carcinoma fine needle aspiration (FNA) cytology specimens: method, preliminary results and prognostic associations.

We have assessed the multiple biological variables on breast carcinoma FNA specimens using a Cytoblock technique. The growth fraction (MIB1), oestrogen receptor (ER), progesterone receptor (PR), p53 mutant protein, c-erbB-2, epidermal growth factor receptor (EGFR), NCRC11/epithelial membrane antigen (EMA) and DNA plopidy were examined. Objective quantification using image analysis (CAS 200) was applied as appropriate. Fifty cases were examined in this preliminary study. Excellent correlation between the Cytoblock preparations and parallel tissue sections was seen. Of the cancers, 81% were aneuploid with only 19% diploid in character, but 67% of the carcinomas were of histological grade 3. The mean nuclear area staining with MIB1 was 31.3% and with ER was 26.7%. Twenty-four percent (24.1%) of the nuclear area showed immunoreactivity with PR. Significant EGFR and EMA, respectively. A significant association between histological grade of the resected tumours and both MIB1 (P = 0.04) and EGFR (P = 0.02) expression in the Cytoblock samples was seen. p53 (P = 0.03) and EGFR (P = 0.01) immunoreactivity showed an association with tumour size. EGFR (P = 0.04) immunostaining also showed a relationship with the lymph node status of the patient. The technique is, we believe, a useful one for the assessment of multiple variables on breast cytology specimens; these preliminary data suggest that some of these may be useful in predicting prognosis in breast cancer patients.

Analysis of Variance↗
PubMed1995

Kinetics of ranitidine metabolism in dog and rat isolated hepatocytes.

1. Freshly isolated hepatocytes from rat and dog have been evaluated as a model for the metabolism of ranitidine in vivo. 2. Isolated hepatocytes from the male and female dog and male Wistar and random hooded rat metabolized ranitidine to ranitidine N-oxide, ranitidine S-oxide, desmethylranitidine and two unidentified minor metabolites. The furoic acid metabolite of ranitidine, previously reported to be a minor metabolite in vivo in rat and dog, was not detected in hepatocytes from either species. 3. The kinetics for ranitidine metabolism in hepatocytes were monophasic for the formation of the three major metabolites in dog and Wistar rat and for N-demethylation of ranitidine in the random hooded rat, but biphasic in this latter strain for the N- and S-oxidation of ranitidine. 4. Ranitidine N-oxide was reduced to ranitidine by Wistar rat hepatocytes but not by hepatocytes from the random hooded rat or dog. Ranitidine S-oxide was metabolized by hepatocytes from both species to one of the unidentified metabolites but was not reduced to ranitidine in either species. Desmethylranitidine was not a substrate for metabolism in hepatocytes from either species. 5. The relative quantitative importance of ranitidine N-oxide, ranitidine S-oxide and desmethylranitidine produced by the hepatocytes was consistent with the profiles of these three metabolites in vivo in rat and dog. The results confirm the value of isolated hepatocytes as a predictive model for in vivo drug metabolism.

Animals↗
PubMed1994

Gibbs free energy of adsorption for biomolecules in ion-exchange systems.

The Gibbs free energy of adsorption (delta G0ads) was estimated for several amino acids, peptides and proteins in a cation-exchange system. Using the steric mass action formalism that describes biomolecular adsorption in ion-exchange systems, the delta G0ads was chromatographically determined under infinitely dilute conditions. The delta G0ads measured for seven globular proteins ranged from -5.7 to -13.9 kcal/mol. The average bond energy (defined as delta G0ads divided by the number of bonds formed between the protein and the surface) for these proteins varied from -1.1 to -1.7 kcal/mol. These bond energies were found to be comparable to the bond energies for lysine and arginine (-1.1 and -1.5 kcal/mol, respectively), the amino acids which primarily contribute to the cation-exchange of proteins. In contrast, an elevated average bond energy of -2.6 kcal/mol was observed for two peptides and protamine (a polypeptide) suggesting that synergistic binding may play a role for unstructured macromolecules, but not for globular proteins.

Absorption↗
PubMed1994

A comparative trial between diclofenac-gentamicin and betamethasone-neomycin drops in patients undergoing cataract extraction.

Eighty patients were randomised in a single-masked parallel-group study to receive topically either the test drug, a diclofenac and gentamicin combination, or a betamethasone and neomycin combination after routine cataract extraction and intraocular lens implantation. Each group was assessed over a 6 week period for post-operative inflammation. The two drug combinations were equally effective in suppressing inflammation in the early post-operative stages and the diclofenac-gentamicin combination was slightly more effective in the later stages. The test drug was well tolerated and showed no adverse effects. We feel it is an effective and relatively safe drug which has a role as an anti-inflammatory agent after cataract extraction and has potential advantages in certain circumstances.

Aged↗
PubMed1994

Molecular genetics of the brown (b)-locus region of mouse chromosome 4. I. Origin and molecular mapping of radiation- and chemical-induced lethal brown deletions.

Over a period of many years, germ-cell mutagenesis experiments using the mouse specific-locus test have generated numerous radiation- and chemical-induced alleles of the brown (b; Tyrp 1) locus in mouse chromosome 4. We describe here the origin, maintenance and initial molecular characterization of 28 b mutations that are prenatally lethal when homozygous. Each of these mutations is deleted for Tyrp 1 sequences, and each of 25 mutations tested further is deleted for at least one other locus defined by molecular clones previously found to be closely linked to b by interspecific backcross analysis. A panel of DNAs from mice carrying a lethal b mutation and a Mus spretus chromosome 4 was used in the fine structure mapping of these molecularly defined loci. The deletional nature of each of these prenatally lethal mutations is consistent with the hypothesis that the null phenotype at b has an effect only on the quality (color) of eumelanin produced in melanocytes. The resulting deletion map provides a framework on which to build future molecular-genetic and biological analyses of this region of mouse chromosome 4.

Alleles↗
PubMed1994

A formalin-inactivated vaccine protects against mucosal papillomavirus infection: a canine model.

A formalin-inactivated canine oral papilloma homogenate was used as a vaccine to prevent infection by the oncogenic, mucosotropic canine oral papillomavirus (COPV) in beagle dogs. Twenty-six dogs received 2 doses of phosphate-buffered saline intradermally and 99 dogs received 2 doses of the inactivated vaccine. One month after the second dose all dogs were challenged with infectious COPV by scarification of the oral mucosa. All of the control dogs developed papillomas by 6-8 weeks after challenge while none of the vaccinated dogs did. This vaccine has been used successfully in approximately 60,000 line bred beagles with no untoward effects and with long-lasting protection. These data demonstrate that a systemically administered, formalin-inactivated vaccine can protect against mucosal infection by COPV and suggest approaches for the development of human papillomavirus vaccines.

Animals↗
PubMed1994

7-Ethoxycoumarin O-deethylase kinetics in isolated rat, dog and human hepatocyte suspensions.

1. A comparative study of the kinetics of the O-deethylation of 7-ethoxycoumarin has been carried out in freshly isolated rat, dog and human hepatocytes. 2. Biphasic kinetics were observed for all three species with apparent Km and Vmax values of 11.5, 2.2 and 3.9 microM and 0.30, 0.21, 0.007 nmol/min/10(6) cells from rat, dog and man, respectively, for the high affinity-low capacity component, and 560, 40, 470 microM and 1.52, 0.74, 0.057 nmol/min/10(6) cells, respectively, for the low affinity-high capacity component. 3. These observed kinetic parameters in hepatocytes from rat and man were similar to published values for microsomes for the same two species. 4. Values for intrinsic clearance of 7-ethoxycoumarin for the three species calculated from the Km and Vmax data were 152, 631 and 6 ml/min/kg for rat, dog and human hepatocytes, respectively. These intrinsic clearance values predict that 7-ethoxycoumarin would be subject to a high hepatic clearance in rat and dog, and low hepatic clearance in man. These values are supported by published data on rat which show that 7-ethoxycoumarin is subject to high clearance.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1994

Iatrogenic lateral rectus palsies. A series of five postmyelographic cases.

The objective of this study was to assess the etiology of lateral rectus palsies in patients undergoing lumbar myelograms with Iopamidol (Isovue; ER Squibb and Sons, Princeton, NJ, USA; Niopam, E Merc, UK.). An audit of the departmental orthoptic record revealed two patients who had suffered abducens palsies after myelograms. A further search revealed three additional patients who had suffered similar complications. The incidence of abducens palsy in patients undergoing myelography with the contrast agent Iopamidol was found to be 1 in 500 in around 2,500 myelograms performed under standard conditions. It would appear that lateral rectus palsy in myelography is the result of the lumbar puncture, the neurotoxic effect of the contrast agent, or a combination of the two in patients with an already compromised neurophysiologic state. This is the first series to associate this problem with Iopamidol. Although usually a serious neurologic symptom, when associated with contrast myelography using Iopamidol it is important to appreciate that such symptoms usually resolve of their own accord.

Abducens Nerve↗
PubMed1993

Use of tumour marker immunoreactivity to identify primary site of metastatic cancer.

OBJECTIVES: To determine whether variations in the expression of tumour related antigens can predict the origin of tumours. DESIGN: Immunohistological study of tumour marker expression in primary adenocarcinomas and respective metastatic deposits. Antibodies to the following tumour markers were used: polymorphic epithelial mucin (NCRC-11 and SM3), carcinoembryonic antigen, carcinoembryonic antigen with non-specific antigen co-specificity, CA125, CA19.9, prostate specific antigens, and thyroglobulin. SETTING: Histopathology department of teaching hospital. SUBJECTS: 100 pathology sections of metastatic adenocarcinoma and their related primary tumours. MAIN OUTCOME MEASURES: Concordance of reactivity between primary and metastatic tumours. Reactivity profiles of tumour sites. RESULTS: The correct primary site of origin was predicted in 70% (33/47) of tumours in men and 54% (27/43) tumours in women with antibodies SM3, 288, CA19.9, CA125, and PSA (men only). Specificities ranged from 68% for breast tumour to 98% for prostate tumour. CONCLUSION: Use of tumour markers in patients presenting with metastatic adenocarcinoma of unknown origin can help localise the probable primary sites and reduce the need for extensive and expensive imaging techniques.

Adenocarcinoma↗
PubMed1993

p53 protein expression in mammary ductal carcinoma in situ: relationship to immunohistochemical expression of estrogen receptor and c-erbB-2 protein.

The immunohistochemical expression of the p53 gene protein was examined in a consecutive series of 143 cases of pure ductal carcinoma in situ (DCIS) of the breast. Expression of wild-type and/or mutant p53 protein was detected in 36 (25.2%) of the cases examined, as evidenced by positive nuclear staining with the monoclonal antibody DO 7. Thirty-four (35.8%) of the large cell cases showed p53 protein expression compared with two (4.1%) of the small cell cases (chi 2 = 15.3 [df = 1], P < .001). p53 Protein expression also was associated with an increased histologic degree of necrosis, with a nearly significant association of negative tumor estrogen receptor status and p53 protein expression. No significant association of p53 protein expression and c-erbB-2 protein expression was seen. Immunohistochemical expression of p53 protein is present in approximately 25% of DCIS cases and is confined almost exclusively to large cell DCIS, a morphologic subtype of in situ breast carcinoma thought to be more biologically aggressive. Expression of p53 protein may be important in the neoplastic progression of DCIS, reflecting the acquisition of p53 gene mutations in large cell DCIS cases. Therefore, p53 may be implicated in mammary tumor evolution from in situ to invasive disease.

Biomarkers, Tumor↗
PubMed1993

Selective blockade of spinal reflexes by omega-conotoxin in the isolated spinal cord of the neonatal rat.

High-voltage-activated calcium currents can be pharmacologically separated into two components: omega-conotoxin-sensitive, dihydropyridine resistant (N-type) and dihydropyridine sensitive, omega-conotoxin-resistant (L-type). In the present study, omega-conotoxin completely blocked spinal monosynaptic responses and long-latency electrically evoked polysynaptic reflexes were 93% blocked. Short-latency electrically evoked and capsaicin-evoked polysynaptic reflexes were partially blocked (39 and 37% block, respectively). Nifedipine, a dihydropyridine type antagonist, had no effect on any evoked responses and Bay K 8644, a dihydropyridine agonist, only increased spontaneous firing. Dynorphin A blocks N currents, but its depressant effects were not altered by irreversible blockade of omega-conotoxin-sensitive N channels. These results demonstrate that omega-conotoxin-sensitive N channels play a major role in the synaptic transmission that mediates monosynaptic and electrically evoked slow polysynaptic reflexes, and a lesser but significant role in fast and capsaicin-evoked polysynaptic spinal reflexes. L-type channels play a minor role. Furthermore, dynorphin A depresses synaptic transmission by blockade of high threshold calcium channels that are distinct from the omega-conotoxin-sensitive N channel, or by a mechanism that does not directly involve calcium channels.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1993

Oestrogen receptor expression in ductal carcinoma in situ of the breast: relationship to flow cytometric analysis of DNA and expression of the c-erbB-2 oncoprotein.

The expression of oestrogen receptor protein (ER) was examined in 151 cases of symptomatic or screening detected pure ductal carcinoma in situ (DCIS) of the breast by immunocytochemical assay (ERICA), in formalin-fixed paraffin-embedded tissue, with the monoclonal antibody H 222 (Abbott). Forty-eight tumours (31.8%) of cases were ER positive. Twenty-seven (17.9%) of cases showed high level ER expression and 21 (13.9%) of cases showed low level ER immunoreactivity. Significant associations of positive tumour ER immunoreactivity and non-comedo architecture chi 2 = 6.76; (d.f. = 1): P < 0.001, small cell size chi 2 = 4.49; (d.f. = 1): P = 0.034, higher S-phase fraction chi 2 = 4.71; (d.f. = 1): P = 0.03 and lack of c-erbB-2 protein overexpression chi 2 = 7.96; (d.f. = 1): P < 0.01 were identified. No significant associations of ER expression and patient age, histological grade of necrosis in DCIS, or DNA ploidy were found. ER expression is detectable in less than one third of symptomatic and screening detected cases of DCIS, implying that endocrine therapy of DCIS may be a more appropriate form of management for morphological subtypes of DCIS which show higher rates of oestrogen receptor expression, particularly those of non-comedo and small cell type.

Adult↗
PubMed1993

Methodology of immunohistological detection of oestrogen receptor in human breast carcinoma in formalin-fixed, paraffin-embedded tissue: a comparison with frozen section methodology.

We describe a method of immunohistochemically assessing estrogen receptor status on routinely processed formalin-fixed tissue, using a commercially available monoclonal antibody (Abbott H222), with pronase predigestion of tissue sections and overnight antibody incubation. The staining was assessed using the H score system. A series of 94 cases of breast cancer were analysed and the results were compared with assessment by oestrogen receptor immunocytochemical assay performed on frozen section. Direct comparison of the paired sets of H scores obtained with frozen tissue and formalin-fixed tissue showed a highly significant correlation of 0.8 (P < 0.001) between the two methods of oestrogen receptor assessment. Chi-squared analysis using H score cut off points of 50 and 100 also showed a similar significant association (P < 0.001). We conclude that this oestrogen receptor method, applicable to formalin-fixed, paraffin-embedded tissue, gives accurate results on routinely fixed tissue and could be used as an alternative to other methods.

Adenocarcinoma↗
PubMed1993

Design of helix ends. Amino acid preferences, hydrogen bonding and electrostatic interactions.

The amino acid sequence and chemical interactions at the ends of 163 helices were surveyed so as better to understand amino acid preferences previously observed [Richardson, J.S. & Richardson, D.C. (1988) Science 240, 1648-1652]. Amino acid preferences differed from the previous survey in some significant details and in ways that might affect the choice of amino acids during the design of a protein helix. The following major conclusions about helix ends were deduced from additional patterns of amino acid occurrence and interactions that were observed. (1) A specific pair of hydrogen bonds is often observed between a glutamic acid (or glutamine) side chain at the N3 position and the N-cap amide hydrogen, and between the N-cap side chain (often threonine) and the N3 amide hydrogen. This reciprocal interaction may be an important means of stabilizing the N-terminal end of a helix. (2) Negatively charged amino acids (aspartic acid and glutamic acid) at the N-terminal end of helices may be more important in stabilizing protein helices than positively charged residues (chiefly lysine) at the C-terminal end. (3) The identity of the residue at the N-cap position is correlated with the backbone conformation at that position. (4) Aspartic acid (or asparagine) at the N2 or N3 position may adopt a conformation that suggests a hydrogen-bonding interaction with the end of the helix, especially when the N-cap side chain does not form a hydrogen bond with the end of the helix.

Amino Acids↗