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C B Williams

Publications and source records attributed to C B Williams.

At least 91 records · Page 5Linked to original sources
PubMed1994

Factors affecting the outcome of endoscopic surveillance for cancer in ulcerative colitis.

BACKGROUND/AIMS: Cancer surveillance in patients with ulcerative colitis is of unproven benefit. This study assesses the efficacy and analyzes factors limiting the success of a surveillance program during a 21-year period in 332 patients with ulcerative colitis to the hepatic flexure and disease duration exceeding 10 years. METHODS: Clinical assessment and sigmoidoscopy with biopsy was undertaken yearly. Colonoscopy and biopsy every 10 cm throughout the colon was performed every 2 years or more often if dysplasia was found. Only biopsy specimens reported as showing dysplasia were reviewed. RESULTS: Surveillance contributed to detection of 11 symptomless carcinomas (8 Dukes A, 1 Dukes B, and 2 Dukes C), but 6 symptomatic tumors (4 Dukes C and 2 disseminated) presented 10-43 months after a negative colonoscopy. Dysplasia without carcinoma was confirmed in 12 symptomless patients who underwent colectomy. The 5-year predictive value of low-grade dysplasia for either cancer or high-grade dysplasia was 54% using current criteria. CONCLUSIONS: Surveillance identified some patients at a curable stage of cancer or with dysplasia. Limiting factors were failure to include patients with presumed distal colitis, biennial colonoscopy, the number of biopsy specimens at each colonoscopy, and variation in histological identification and grading of dysplasia.

Adenomatous Polyps↗
PubMed1994

Tumor necrosis factor alpha-producing cells in the intestinal mucosa of children with inflammatory bowel disease.

BACKGROUND/AIMS: Cytokines are thought to be important in mediating tissue damage in inflammatory bowel disease (IBD). Many of the in vivo activities of tumor necrosis factor alpha (TNF-alpha) match the changes found in IBD, but its importance is controversial. METHODS: A sensitive, reverse hemolytic plaque assay was used to determine the frequency of TNF-alpha secreting cells isolated from mucosal biopsy specimens of children with Crohn's disease or ulcerative colitis (UC) and non-IBD controls before and after medical treatment. RESULTS: Frequency of TNF-alpha secreting cells was significantly increased in biopsy specimens from children with mild, nonspecific inflammation compared with those with histologically normal intestine. Frequency did not increase in UC compared with children with nonspecific inflammation but was significantly greater in Crohn's disease than in UC. After treatment, the frequency of TNF-alpha secreting cells was reduced in patients receiving cyclosporin A, not reduced in patients with steroids or enteral nutrition, and not changed with treatment in UC. CONCLUSIONS: TNF-alpha secreting cells are increased in the mucosa of inflamed intestine, regardless of pathogenesis. In patients with IBD, higher levels are seen in Crohn's disease than in UC, probably reflecting the extensive T-cell activation in Crohn's disease. No relation existed between histological healing and the frequency of TNF-alpha-secreting cells.

Adolescent↗
PubMed1994

Endoscopic features of chronic inflammatory bowel disease in childhood.

Flexible endoscopy, performed after oral bowel preparation and under moderate intravenous sedation, proves to be well tolerated, safe and highly effective in the diagnosis and management of children with IBD. At St Bartholomew's Hospital it is performed as the investigation of first choice, on the basis that it supplies colour documentation, histopathological and (where relevant) bacteriological evidence, which achieves certain confirmation or exclusion in almost every case and in the shortest possible time. Biopsies must always be taken, as mucosa of normal appearance can show either microscopic ulcerative colitis or Crohn's disease. When there are the characteristic 'aphthoid' ulcers, visual diagnosis of Crohn's disease is reasonably certain, particularly in early-stage disease, although amoebic and other infective causes of colitis can give misleadingly similar appearances. The endoscopist can usually inspect (and almost always biopsy) the terminal ileum, and can expect many children to show the prominent 'nodular lymphoid hyperplasia' which is essentially a normal finding-though sometimes misdiagnosed radiologically as being Crohn's deformity. However, it is important that radiological assessment by barium follow-through complements colonoscopy in view of the not infrequent cases of intestinal Crohn's disease in children where the proximal small intestine is involved, even if the colon and terminal ileum are spared.

Child↗
PubMed1994

Cyclosporin as initial treatment for Crohn's disease.

Childhood Crohn's disease may cause significant morbidity. T cell activation is considered to be central to Crohn's disease pathology, and as cyclosporin is a powerful inhibitor of T cell activation, and has been used in adult Crohn's disease with encouraging results, it may offer the prospect of remission if given early in the course of disease. Children with newly diagnosed Crohn's disease or those relapsing off treatment were therefore given cyclosporin or conventional treatment (enteral nutrition or corticosteroids) by random allocation. Evaluation was performed initially and at two months. Twenty four children were studied (10 on cyclosporin and 14 on conventional treatment; one child on cyclosporin withdrew). Significant clinical improvement occurred in the group on conventional treatment, but not in the cyclosporin group. Colonoscopic improvement was noted in 5/9 on cyclosporin and 8/14 on conventional treatment, but neither group produced a significant fall in median colonoscopic index. Histological improvement was seen in 7/8 on cyclosporin and 8/13 on conventional treatment, but cyclosporin was not significantly better. Cyclosporin produced improved clinical and histological appearance without matched improvement in blood disease indices. It was not better than conventional treatment, and simple oral administration is probably not suitable for newly diagnosed patients with Crohn's disease.

Adolescent↗
PubMed1994

Surveillance of duodenal polyps in familial adenomatous polyposis: progress report.

Familial adenomatous polyposis (FAP) is characterized by the presence of premalignant adenomas of the large and small bowel. Prophylactic colectomy deals with the risk for colon cancer, leaving duodenal cancer as the leading cause of death. Although most FAP patients have duodenal adenomas, only approximately 5% develop duodenal cancer. This study looks at progression of duodenal polyps with time. The outcome of endoscopic surveillance in the duodenum of 70 patients with familial adenomatous polyposis was determined. A mean of 40 months elapsed between endoscopies. Outcome was measured using video comparison and a staging system that includes histological assessment. Duodenal cancer developed in one patient, and was suspected in two others. The stage of duodenal polyposis worsened in another seven patients. When histology was ignored, comparison of video recordings in 52 patients showed a worsening in 21 (40%). In conclusion, further surveillance appears warranted so that patients at high risk for duodenal cancer might receive early treatment. Should slow progression of duodenal polyposis be shown to be associated with low risk, then most patients can be safely offered less frequent endoscopies than hitherto.

Adenomatous Polyposis Coli↗
PubMed1994

Implications of genetic changes in body composition on beef production systems.

Changing the body composition of beef has implications for the entire beef production system. The dynamic nature of an animal's body composition and the production system itself make predictions of the implications of genetic change in body composition difficult. The cow-calf, stocker, and feeder segments of the production system will be affected differently. Leaner cattle tend to be slaughtered at heavier weights. Heavier weights effectively reduce composition differences of slaughter beef to less than the genetic differences. The effects of four pricing scenarios on slaughter weight and composition were evaluated for two leaner genotypes, one with no change in marbling and one with reduced marbling. A genetic difference of 1.0 yield grade at the same carcass weight resulted in slaughter beef that differed by .4 to 1.0 yield grade because of increased slaughter weights. Separate analyses suggested the stocker segment of beef production will be least affected by changes in body composition. Genotypes that are best fitted to slaughter requirements will have the most flexibility in types of stocker systems that can be used. The cow-calf segment of beef production has several options to adapt to leaner cattle. Management to reduce nutritional stress on leaner cows may be required by some producers. Increased selection for reproductive traits in cow genotypes may be needed. An alternative to selection for reproduction is terminal crossing to partially disassociate the slaughter animals' genotype from the cow's genotype.

Animal Husbandry↗
PubMed1993

Randomized controlled trial of the effect of sulindac on duodenal and rectal polyposis and cell proliferation in patients with familial adenomatous polyposis.

Twenty-four patients with familial adenomatous polyposis who had previously undergone prophylactic colectomy and had advanced duodenal polyposis were entered into a randomized trial to assess the effect of the non-steroidal anti-inflammatory drug sulindac on duodenal and rectal polyps. Polyp size and number were assessed by videotaped duodenoscopy (and rectoscopy in 14 patients) at entry and after 6 months of treatment; the tapes were compared by two assessors who were unaware of the randomization and the shuffled chronological order of the recordings. Mucosal cell proliferation was measured by in vitro incorporation of 5-bromo-2'-deoxyuridine. Sulindac therapy was associated with a reduction in epithelial cell proliferation in the duodenum (median labelling index (LI) 15.8 versus 14.4 per cent, P = 0.003) and a trend towards duodenal polyp regression (P = 0.12). In the rectum, cell proliferation showed a marked reduction (median LI 8.5 versus 7.4 per cent, P = 0.018), and significant (P = 0.01) polyp regression was seen. Rectal polyposis was less severe than that in the duodenum and responded more dramatically. Sulindac is a possible treatment for patients in whom rectal polyps have failed to show significant regression after ileorectal anastomosis and who are unsuitable for pouch surgery; it may be useful in early duodenal polyposis or as an adjunct after duodenal clearance.

Adenomatous Polyposis Coli↗
PubMed1993

Rectal bleeding and polyps.

Colorectal polyps are an important albeit uncommon cause of rectal bleeding in children. Colonoscopy promotes both rapid and accurate diagnosis and the opportunity for immediate therapeutic polypectomy. A 10 year audit of polyps diagnosed and treated endoscopically has been undertaken in the children's endoscopy unit. Twenty nine polyps were diagnosed from 730 colonoscopies; 24 were juvenile, two inflammatory, two Peutz-Jeghers, and one an adenomatous polyp. All but one of the juvenile polyps were solitary. All children had bleeding per rectum as one of the major presenting features. About two thirds of the patients were under the age of 5 years; the mean age was 5.6 years. Most of the juvenile polyps were on the left side of the colon; 41% were distal to the sigmoid colon. However polyps were found throughout the colon, indicating that total colonoscopy is wise and rewarding in any child with persistent and intermittent rectal bleeding.

Adolescent↗
PubMed1992

Alleles of the rat T-cell receptor beta chain gene complex.

Inbred rat strains provide a rich source of genetic diversity in immunologically relevant genes. We have characterized the alleles of one of these genes, encoding the rat T-cell receptor C beta 1 chain, by Southern blots and nucleic acid sequencing. The Cb1 gene segments from DA and LEW rats display complex allotypic variation: both coding and noncoding regions contain multiple nucleotide substitutions. In addition, there is a polymorphic insertion of a rat repetitive LINE element 3' to the coding region. The Cb1 alleles are one part of larger Tcrb haplotypes, containing V beta, D beta, and J beta elements; complete Cb1 genomic nucleotide sequences, and a partial list of the strain distribution of the two alleles, are described in this report.

Alleles↗
PubMed1992

The real magic.

Explore the source record for details and available documents.

Adult↗
PubMed1992

Congenital hypertrophy of retinal pigment epithelium in patients with colonic polyps associated with cancer family syndrome.

Congenital hypertrophy of retinal pigment epithelium (CHRPE) has been shown to be a frequent extracolonic manifestation of adenomatous polyposis coli (APC). The presence of CHRPE in patients with adenomatous polyps from families with cancer family syndrome suggests possible involvement of the APC gene locus in syndromes associated with less florid polyp formation than seen in APC. It also emphasises that caution must be exercised in using the presence of CHRPE clinically as a marker for APC in isolated at-risk individuals.

Adenoma↗
PubMed1992

Rectal polyposis as a guide to duodenal polyposis in familial adenomatous polyposis.

Almost all patients with familial adenomatous polyposis (FAP) develop duodenal polyps, the severity of which is graded stage 1 (minor) to stage V (cancer). Regular endoscopy is recommended for all patients with FAP. To test whether the development of severe duodenal polyposis could be predicted in another way, rectal and duodenal polyp severity were compared in 91 patients with FAP. The fulguration ratio (number of rectal fulgurations divided by number of years since colectomy) supplied the rectal polyp severity index. Patients with stage V duodenal polyposis had significantly higher fulguration ratios (median 0.38) than did patients with stage 1 disease (median 0; P = 0.009). However, the wide scatter of results means that rectal polyp severity cannot be used as a guide to duodenal polyp severity in individual patients. The coexistence of populations with severe duodenal and rectal polyposis suggests that environmental factors are important in phenotypic expression in FAP.

Adenomatous Polyposis Coli↗
PubMed1992

A computer model to predict empty body weight in cattle from diet and animal characteristics.

A computer model was developed to predict empty BW in cattle as a function of diet (forage NDF, physical form of forage [hay vs silage and pasture], proportion of dietary concentrates) and animal (full BW) characteristics. The model was empty BW = full BW * (1 - GFILL), where GFILL is gut fill expressed as a fraction of full BW. An equation obtained from published data (GFILL = .05354 + .329 * NDF) was used to provide a base prediction of GFILL from the fraction of NDF in the forage. Predicted GFILL was then corrected for full BW, physical form of forage, and fraction of concentrates using multiplicative factors obtained from published data. The model was evaluated with data from 11 published experiments. Several breeds of cattle, a wide range of forage types, and diets with 0 to 93% concentrates were represented in these data. Observed values for empty BW were compared to model-predicted values and to values predicted by systems published by the Agricultural Research Council (ARC) and National Research Council (NRC). Sums of squared deviations of predicted values from observed (n = 64) were 3,074, 37,327, and 25,920 for the model, ARC, and NRC systems, respectively. After fitting predicted empty BW values to observed values, proportion of concentrates and forage NDF accounted for a significant (P less than .01) amount of the residual variation with the ARC and NRC systems, but not for the model. This finding suggests that the model will predict empty BW more accurately than the ARC and NRC systems with diets similar to those used in the evaluation.

Animal Feed↗
PubMed1992

A computer model to predict the effects of level of nutrition on composition of empty body gain in beef cattle: I. Theory and development.

A computer model was developed to simulate differences in the composition of empty body gain of beef cattle resulting from differences in postweaning level of nutrition that are not associated with empty BW. Differences in rate of empty body gain of cattle of similar genotype reflect differences in the level of nutrition; hence, empty body gain was used to represent level of nutrition. The model was based on four assumptions: 1) as animals mature, the proportion of fat is greater in gain than in body weight, 2) effects on body composition caused by plane of nutrition that are not associated with empty BW are predictable from rate of empty BW gain, 3) effects resulting from changes in nutrition are not exerted immediately nor are they permanent, and 4) cattle approach an empty body composition equilibrium when empty body gain is zero. Six parameters were used to characterize mature fat-free matter, rate of change to body composition equilibrium, minimum and maximum fractional growth rate relative to fractional growth rate for empty BW, time lag of response to change in nutrition, and influence of stage of maturity and nutrition on rate of change for fat-free matter. Two parameters were specific for genotype and gender. Using results from the model, we were able to explain conflicting results obtained from compensatory gain experiments.

Adipose Tissue↗