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Biomedical subjects

C Fisher

Publications and source records attributed to C Fisher.

At least 217 records · Page 12Linked to original sources
PubMed1996

Interphase fluorescence in situ hybridization and reverse transcription polymerase chain reaction as a diagnostic aid for synovial sarcoma.

Identification of the t(X;18)(p11.2;q11.2) that is associated with a high proportion of synovial sarcoma can be a useful diagnostic aid. The translocation results in fusion of the SYT gene on chromosome 18 to either the SSX1 or the SSX2 gene, two homologous genes within Xp11.2. Two-color interphase fluorescence in situ hybridization and reverse transcription polymerase chain reaction were assessed as approaches to identify the rearrangement in well characterized cases. The presence of the translocation, and the specific chromosome X gene disrupted, were inferred from the configuration of signals from chromosome-specific centromere probes, paints, and markers flanking each gene in preparations of interphase nuclei. Rearrangement was found in two cell lines and eight of nine tumor samples, including analysis of five touch imprints. This was consistent with cytogenetic data in four cases and reverse transcription polymerase chain reaction analysis using primers known to amplify both SYT-SSX1 and SYT-SSX2 transcripts. The transcripts were distinguished by restriction with LspI and SmaI. Contrary to previous suggestions, there was no obvious correlation between histological subtype and involvement of the SSX1 or SSX2 gene. These approaches could also be applied to the identification of tumor-free margins and metastatic disease.

Adolescent↗
PubMed1996

Reducing time in bed after cardiac catheterization (TIBS II)

BACKGROUND: More than 500,000 cardiac catheterizations are done annually in the United States for both the diagnosis and treatment of patients with coronary artery disease. A femoral artery catheter insertion site is usually used for these procedures, and postprocedure protocols call for prolonged bed rest with restricted patient movement. Time-in-bed standards vary widely, from 3 to 12 hours after cardiac catheterization to more than 24 hours of bed rest after angioplasty. Bed rest with restricted movement causes patient discomfort, increases nursing workload, and prolongs length of hospital stay. OBJECTIVE: To determine if there would be a significant difference in the incidence of bleeding from femoral artery insertion sites between cardiac catheterization patients who remained in bed for 4 hours and those who remained in bed for 6 hours after sheath removal. METHODS: An experimental-control group design was used with a convenience sample (N = 86) of adult patients undergoing diagnostic coronary angiography. Patients were randomly assigned to remain in bed for 4 hours (experimental) or 6 hours (control) after arterial sheath removal. Both groups had pressure dressings and sandbags in place over the insertion site during time in bed. RESULTS: There was no significant difference in the incidence of bleeding related to out-of-bed activity between the groups (chi-square = .31, df = 1). CONCLUSIONS: Requisite time in bed after cardiac catheterization can be safely decreased from 6 to 4 hours. This change has implications for enhancing patient comfort and decreasing both length of hospital stay and healthcare costs.

Aged↗
PubMed1996

Acoustic cues to grammatical structure in infant-directed speech: cross-linguistic evidence.

Several theorists have suggested that infants use prosodic cues such as pauses, final lengthening, and pitch changes to identify linguistic units in speech. One potential difficulty with this proposal, however, is that the acoustic shape of an utterance is affected by many factors other than its syntax, including its phonetic, lexical, and discourse structure. This has raised questions about how the infant could use timing and pitch as cues to any aspect of linguistic structure without simultaneously factoring out other effects. Acoustic analyses of connected samples of spontaneous speech addressed to 13.5-14-month-old infants by American English- and by Japanese-speaking mothers revealed that both utterance- and phrase-level acoustic regularities were large enough to be detected in spontaneous speech without correcting for other influences on the same acoustic features. (1) Utterance-final vowels were lengthened and underwent exaggerated pitch changes in both languages, and (2) local acoustic changes in duration (English) or pitch (Japanese) were reliably associated with some phrase boundaries within utterances. These findings suggest that a naive listener could estimate a rough prosodic template for each language based on robust acoustic patterns in observed sentences. We discuss ways in which the learner could combine acoustic and distributional analyses across utterances to acquire language-specific variations in prosodic bracketing cues and to obtain indirect perceptual evidence for the internal structure of utterances.

Child Development↗
PubMed1995

A mutation in codon 717 of the amyloid precursor protein gene in an Australian family with Alzheimer's disease.

DNA from the probands of seven Australian families with hereditary Alzheimer's disease was screened for the presence of known mutations in the amyloid precursor protein (APP) gene on chromosome 21 using single stranded conformational polymorphism (SSCP) analysis [14]. One subject was found to have a mutation causing a Val-->Ile substitution at position 717. This was confirmed by restriction enzyme digestion and sequencing. The mutation has been found in both the other affected family members available for study and in two at-risk relatives. It was not present in the only living unaffected relative who has passed the usual age of onset in this family. There is so far no evidence that apolipoprotein E (APOE) genotype influences age of onset in this family, though numbers are small. Two other families with autopsy confirmation and age of onset in the fifth decade had no APP mutation and are thought likely to have a mutation on chromosome 14 on the basis of their earlier onset age.

Alzheimer Disease↗
PubMed1995

Head and neck liposarcoma.

BACKGROUND: Liposarcoma of the head and neck region represents approximately 1% of head and neck sarcomas. Therefore, there are few data on the natural history, presentation, treatment, and prognosis of this neoplasm. METHODS: This study is a report of data from 76 patients with head and neck liposarcoma of whom 4 were treated at The Royal Marsden Hospital during the past 50 years. RESULTS: The median age of patient presentation was the seventh decade (range, 6 months-86 years), and 65% of the patients were male. The commonest site of presentation was the neck (28%), followed by the larynx (20%) and pharynx (18%). Sixty-two percent of tumors were low grade (well differentiated and myxoid), and 38% were high grade (pleomorphic and round cell). The principal determinant of outcome was histologic grade. Five-year survival by life-table analysis was 67% overall and varied with tumor type as follows: well differentiated 100%, myxoid 73%, pleomorphic 42%, and round cell 0%. Site appears to have had some influence on prognosis. Oral liposarcoma had a poor prognosis with a 5-year survival of 50%, despite the low grade of all tumors; however, the 5-year survival for laryngeal (89%) and head (83%) liposarcoma was considerably better. Tumor size did not affect prognosis. The mainstay of treatment was surgical excision, used alone in 70% of the cases. Radiotherapy was used with other treatments in 25% of the cases. Prognosis was best for patients treated with surgery only (5-year survival, 83%), compared with those receiving surgery plus radiotherapy (5-year survival, 63%), chemotherapy (5-year survival, 33%), and radiotherapy alone (5-year survival, 0%). CONCLUSIONS: Liposarcoma rarely involves the head and neck region. The prognosis for patients with this disease appears to be better than for those with liposarcoma arising elsewhere, particularly in the retroperitoneum. Prognosis is principally dependent on histologic grade. Complete surgical excision provides the most effective treatment.

Adolescent↗
PubMed1995

ApoE genotypes in Australia: roles in early and late onset Alzheimer's disease and Down's syndrome.

We studied the apoE genotypes of 279 Australians in order to determine what relationships might exist in this group between apoE genotype and dementia associated with either early- or late-onset sporadic Alzheimer's disease (AD) or with Down's syndrome (DS). ApoE epsilon 4 allele frequency was increased in Australians with either early-onset sporadic AD (p < 0.002) or late-onset sporadic AD (p < 0.0001) and apoE epsilon 2 allele frequency was decreased in the late-onset sporadic AD group (p < 0.01). The apoE genotype distribution among patients with DS was not different from that of the control group. One individual with DS and an apoE epsilon 4/epsilon 4 genotype developed dementia at the earliest age of dementing DS patients, consistent with a role for apoE epsilon 4 in determining age of onset of dementia in AD and DS. Another DS patient with an apoE epsilon 2/epsilon 3 genotype developed dementia within an age range similar to that of four demented DS patients with an apoE epsilon 3/epsilon 3 genotype, an observation which would appear inconsistent with the proposed protective effect of apoE epsilon 2 to delay onset of dementia in DS. These results extend the evidence that the apoE genotype, particularly apoE epsilon 4, modulates dementia in early- and late-onset sporadic AD and DS. The protective role of apoE epsilon 2 in DS, however, may vary among different populations or ethnic groups.

Age of Onset↗
PubMed1995

Fusion of SYT to two genes, SSX1 and SSX2, encoding proteins with homology to the Kruppel-associated box in human synovial sarcoma.

We demonstrate that the cytogenetically defined translocation t(X;18)(p11.2;q11.2) found in human synovial sarcoma results in the fusion of the chromosome 18 SYT gene to either of two distinct genes, SSX1 or SSX2, at Xp11.2. The SSX1 and SSX2 genes encode closely related proteins (81% identity) of 188 amino acids that are rich in charged amino acids. The N-terminal portion of each SSX protein exhibits homology to the Kruppel-associated box (KRAB), a transcriptional repressor domain previously found only in Kruppel-type zinc finger proteins. PCR analysis demonstrates the presence of SYT-SSX1 or SYT-SSX2 fusion transcripts in 29 of 32 of the synovial sarcomas examined, indicating that the detection of these hybrid transcripts by PCR may represent a very useful diagnostic method. Sequence analysis has demonstrated heterogeneity in the fusion transcripts with the formation of two distinct SYT-SSX1 fusion junctions and two distinct SYT-SSX2 fusion junctions.

Adolescent↗