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N Knight

Publications and source records attributed to N Knight.

15 recordsLinked to original sources
PubMed2002

A case of myoepithelial carcinoma displaying biallelic inactivation of the tumour suppressor gene APC in a patient with familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) is an autosomal dominant disorder caused by mutation of the APC gene. It is characterised by the appearance of hundreds to thousands of colorectal adenomas in adolescence and the subsequent development of colorectal cancer. Various extracolonic malignancies are associated with FAP, including desmoids and neoplasms of the stomach, duodenum, pancreas, liver, and brain. We present a family affected by FAP with an exon 14 APC mutation displaying two rare extracolonic lesions, a hepatoblastoma and a myoepithelial carcinoma. The hepatoblastoma was found in a male patient aged 2 years. The second lesion, a myoepithelial carcinoma of the right cheek, was found in a female patient aged 14 years. Inactivation of the normal APC allele was demonstrated in this lesion by loss of heterozygosity analysis, thus implicating APC in the initiation or progression of this neoplasm. This is the first reported case of this lesion in a family affected by FAP.

Adenomatous Polyposis Coli↗
PubMed1999

Severe disruptive vocalizers.

OBJECTIVES: To describe the most severe disruptive vocalizers in nursing facilities, in regard to their clinical and behavioral characteristics, staff responses, and treatments used, and to report on their prognosis over 6 months. DESIGN: A longitudinal cohort study. SETTING: One hundred seven skilled nursing facilities. PARTICIPANTS: The 203 residents who were among the two most disruptive vocalizers in their respective facilities and who vocalized at least 2 hours a day. MEASUREMENTS: Telephone interviews of licensed nursing staff who cared for the subjects, conducted at baseline, 2, 4, and 6 months. Data gathered included subject demographics, physical function, diagnoses, medication and restraint use, behavioral problems, vocalization characteristics, treatments used, and status at follow-up. RESULTS: Subjects tended to have dementia, to be dependent in most activities of daily living, to have multiple medical problems, to be physically restrained (48%), and to be taking psychotropic medication (76%). Nearly all (95%) were audible at least 50 feet away, with loudness associated with more severe cognitive impairment (OR 4.90, P = .001). When subjects who primarily made nonverbal noises ("screamers") were compared with those whose predominant expressions were words ("talkers"), hearing impairment, severe cognitive impairment, and greater dependency in activities of daily living characterized the screamers. Staff reported trying a variety of treatments with all subjects, often with little success. Two months after enrollment, 66% of surviving subjects vocalized fewer hours than at baseline, and 45% were rated as improved. Independent predictors of improvement included greater ADL independence, hearing and vision problems, shorter length of stay, urinary incontinence, and use of a treatment other than one-on-one interventions. Nearly one-quarter of subjects (23.4%) died within 6 months. Baseline factors associated independently with a higher probability of death included age, use of activity intervention, physical abusiveness, and absence of wandering. CONCLUSION: Severe disruptive vocalization is associated with severe cognitive and physical impairment and with a high probability of mortality within 6 months. Subcategorization of severe vocalizers by vocalization type or other associated factors may be useful for prognostic and treatment purposes.

Activities of Daily Living↗
PubMed1998

A family with attenuated familial adenomatous polyposis due to a mutation in the alternatively spliced region of APC exon 9.

A family is presented with attenuated familial adenomatous polyposis of variable phenotype. The clinical features range from sparse right-sided polyposis and cancer in the proximal colon at the age of 34 to pan-colonic polyposis and cancer at the age of 68. Rectal sparing is common to all affected members. Heteroduplex analysis detected bands of altered mobility in exon 9 of the APC gene in all affected family members. Subsequently, a frameshift mutation was found in the alternatively spliced region of exon 9 at codon 398 which resulted in a stop signal 4 codons downstream. Alternatively spliced transcripts that delete the mutation were readily amplified from normal colonic mucosa and therefore create a mechanism for the attenuated phenotype seen in this family.

Adenomatous Polyposis Coli↗
PubMed1997

Severe upper gastrointestinal polyposis associated with sparse colonic polyposis in a familial adenomatous polyposis family with an APC mutation at codon 1520.

BACKGROUND: Familial adenomatous polyposis usually results in colonic polyposis with hundreds to thousands of polyps, congenital hypertrophy of the retinal pigment epithelium (CHRPE), and variable extracolonic features. Recent reports indicate that patients with distal mutations between codons 1445 and 1578 do not express CHRPE and have a high incidence of desmoid tumours. PATIENTS: The family studied has an unusual phenotype of sparse colonic polyposis but profuse upper gastrointestinal polyposis. Affected subjects do not have CHRPE. METHODS: The protein truncation test followed by sequencing identified a 2 base pair deletion at codon 1520 in the APC gene. This results in a frameshift creating a stop codon 13 codons downstream. RESULTS: This family demonstrates that sparse colonic polyposis but severe upper tract polyposis may be associated with mutations between codons 1445 and 1578. CONCLUSIONS: Study of duodenal and colonic polyps in further cases with mutations in this region is warranted. Such mutations may preferentially cause duodenal adenomas and desmoid tumours as somatic mutations in these tumours also occur in this region, unlike colorectal tumours where somatic mutations occur more proximally. This study emphasises the importance of screening the upper gastrointestinal tract even when the colonic disease is mild.

Adenomatous Polyposis Coli↗
PubMed1996

An evaluation of new gel matrices for the separation of PCR-amplified DNA fragments.

It has been shown that the novel gel matrix, PCR Purity Plus which consists of a vinyl-polymer of polyacrylamide, provides a superior and rapid means of separating DNA fragments. As this product has been discontinued, the two new commercial versions of this matrix (MDE and GeneAmp) with PCR Purity Plus were compared. Optimal conditions for resolving DNA fingerprint profiles for both matrices were defined. Both MDE and GeneAmp gels provided a clear separation of DNA fragments. However, the profiles obtained on GeneAmp gel were closest to that of PCR Purity Plus. These results should be useful to DNA fingerprinting studies where it is critical to obtain a clear resolution of complex DNA profiles.

DNA↗
PubMed1994

Computer image analysis in the diagnosis of melanoma.

BACKGROUND: It is often difficult to differentiate early melanoma from benign pigmented lesions of similar clinical appearance. OBJECTIVE: Our purpose was to develop a computer image analysis system that has the potential for use as an adjunct to the clinical distinction of melanoma from less serious pigmented lesions. METHODS: The system, consisting of a hand-held device incorporating a color video camera and color frame grabber mounted in a microcomputer, was used in a pigmented lesion clinic. Analysis software extracted features relevant to the size, color, shape, and boundary of each lesion, and these features were correlated with clinical and histologic characteristics on which standard diagnoses of skin tumors are based. For discriminant analysis based on image analysis measurements, equal prior probabilities were assigned to two specified diagnostic groups, namely melanoma and "other pigmented lesions," most of which were melanocytic nevi. RESULTS: In a 20-month period, video images of 164 unselected pigmented lesions for which complete diagnostic data were available were successfully captured using the camera. Sixteen of 18 melanomas, and 89% of pigmented lesions overall, were correctly classified by the image analysis system, compared with 83% based on clinical gradings of lesion characteristics. CONCLUSION: Computer image analysis has the potential to provide a valuable diagnostic aid that could enable clinicians to make highly sensitive and specific diagnoses of early, curable melanoma.

Adolescent↗
PubMed1993

Exclusion of APC and MCC as the gene defect in one family with familial juvenile polyposis.

BACKGROUND: In familial juvenile polyposis, multiple juvenile polyps occur throughout the colon. The genetic defect has not been characterized. The risk of colon cancer is increased, although the magnitude of the increased risk is controversial. The hypothesis of this study was that the genetic defect is within a tumor suppressor gene, possibly one already known to be inactivated in colorectal neoplasia. METHODS: Linkage analysis using the short tandem repeat polymorphism D5S346 was performed to determine if juvenile polyposis was linked to either APC (adenomatous polyposis coli) or MCC (mutated in colorectal carcinoma) genes within a single large family. RESULTS: A family in which eight subjects have been affected by juvenile polyposis over three generations is described. Six affected subjects had colectomies in childhood, but the two who have so far survived beyond 35 years of age have developed adenocarcinoma of the jejunum. Within this family, linkage analysis excluded linkage of the juvenile polyposis trait to either APC or MCC. CONCLUSIONS: In a family with juvenile polyposis with a clear predisposition to malignancy, including carcinoma of the jejunum, APC and MCC were not the defective genes causing the condition.

Adenomatous Polyposis Coli↗
PubMed1989

Seventy-five years of the RSNA (Radiological Society of North America), approaching a century of radiology: museum and information resources.

As the Centenary approaches, the feel of radiology history is changing. As exhibits are mounted and the sub-specialties tell their own stories, what once seemed a very new field is acquiring a codified history of its own. That story is made up, to a very large extent, by the things and memories we happen to have kept. As we move into a second century of radiology, the question of what to save and how to save it becomes even more challenging.

Germany↗
PubMed1987

Protection between different serotypes of bovine rotavirus in gnotobiotic calves: specificity of serum antibody and coproantibody responses.

In a previous study, different U.S. isolates of bovine rotavirus were studied for their serotypes and cross-protective properties (G. N. Woode, N. E. Kelso, T. F. Simpson, S. K. Gaul, L. E. Evans, and L. Babiuk, J. Clin. Microbiol. 18:358-364, 1983). Three viruses belonging to two different serotype groups were used as vaccines in gnotobiotic calves, which were subsequently challenged with B641 or B223, representing the two bovine serotypes. In the present work, the experiments were repeated with more calves and the specificity of their antibody responses was measured and compared with the results of the protection studies. Protection between different serotypes occurred under both homologous and heterologous conditions but was not directly serotype dependent. B223 virus showed both homologous and heterologous protection against B223 and B641 challenge viruses. This was a one-way reaction, as B641 did not induce protection against B223. Neonatal calf diarrhea virus vaccine produced neither homologous (against B641) nor heterologous (against B223) protection. The plaque reduction neutralization titers of serum antibody and coproantibody did not predict a state of protection against the challenge virus. Calves vaccinated with neonatal calf diarrhea virus or B641 developed neutralizing antibodies to their respective heterologous challenge viruses but were not protected. After challenge, the boosted coproantibody plaque reduction neutralization response to the original vaccine virus was greater than that to the challenge virus.

Animals↗
PubMedDate not supplied

Computer image analysis of pigmented skin lesions.

To assist in the distinction of melanoma from benign pigmented lesions, an imaging system was developed, comprising a frame grabber, a microcomputer, a colour video camera and flash lighting with red, green and infrared filters. Over an 18-month period, video images of 70 unselected pigmented lesions for which complete diagnostic data were available, were successfully captured using the camera. Analysis software extracted features relevant to the size, colour, shape and boundary of each lesion, and these features were correlated with clinical and histological characteristics on which standard diagnoses of skin tumours are based. For discriminant analysis based on image analysis measurements, equal probabilities were assigned to three specified diagnostic groups, namely melanoma, naevi and 'other', and four of five melanomas were correctly classified when infrared data were included. However when infrared measurements were omitted, all five melanomas were correctly classified, and the overall accuracy of classification of pigmented lesions was 71%. This system holds promise as an aid in the clinical distinction of melanoma from benign pigmented skin lesions.

Basal Cell Nevus Syndrome↗