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Biomedical subjects

L A Knight

Publications and source records attributed to L A Knight.

At least 19 recordsLinked to original sources
PubMed2003

Combination chemotherapy in advanced gastrointestinal cancers: ex vivo sensitivity to gemcitabine and mitomycin C.

Advanced or metastatic disease is common in both oesophagogastric and colorectal cancers, with poor 5-year survival despite palliative chemotherapy. We have investigated the sensitivity of gastrointestinal tumours to gemcitabine in combination with mitomycin C (GeM), using a modified ex vivo ATP-based tumour chemosensitivity assay (ATP-TCA). Tumour material from 41 colorectal and 22 oesophagogastric cancers were assessed. The GeM combination showed variable but definite activity in most of the samples tested. The results show that GeM achieves >95% inhibition at concentrations within the range achievable clinically in 60% of colorectal tumours (21 out of 35) and 38% of oesophagogastric tumours (five out of 13) tested. We did not identify any significant difference in sensitivity using concurrent or sequential exposure of tumour-derived cells to these two drugs. The results from this study suggest that GeM may be a useful combination in the treatment of advanced gastrointestinal malignancy.

Adult↗
PubMed1997

Partial monosomy for chromosome 22 in a girl with mental retardation.

This report describes a 5-year 6-month-old Chinese girl with partial monosomy for the long arm of chromosome 22. The karyotype was 46,XX/46,XX,del (22) (q13.2). She presented with global developmental delay. Clinical features include seizures, failure-to-thrive, prominent ears, long philtrum and abnormal skin pigmentation on the face and limbs.

Child, Preschool↗
PubMed1997

Variants of chromosome 9 in phenotypically normal individuals.

The human chromosome 9 displays the highest degree of structural variability. Four different types of variants are described including pericentric inversion, extra G-positive band in the q arm, additional G-positive band in the p arm and duplication of band 9q21-q22. It is important to demonstrate inheritance from a phenotypically normal individual in order to differentiate between a variant chromosome and an abnormal chromosome.

Azure Stains↗
PubMed1996

Subtle translocation (18;21) confirmed by FISH in a patient with Down syndrome.

The patient presented with the typical features of Down syndrome; hypotonia, brachycephaly, flattened occiput, bilateral prominent medical epicanthic folds, flat nasal bridge, protruding tongue, low-set dysplastic ears, short broad hands, bilateral clinodactyly and simian crease. The karyotype of this child was originally reported as normal. High-resolution chromosomes revealed extra material on the long arm of chromosome 18. The mother's karyotype showed a reciprocal translocation between the long arm of 18 and the long arm of 21 at band q23 and q22.1, respectively. FISH performed separately with two different 21q cosmid probes gave two signals on the mother's metaphases and three signals on the proband. These findings confirmed that the proband is trisomic for the long arm of chromosome 21 at loci D21S65 and D21S19.

Chromosomes, Human, Pair 18↗
PubMed1996

Fanconi's anaemia and recurrent squamous cell carcinoma of the oral cavity: a case report.

Fanconi's anaemia is a rare genetic disorder and majority of the patients die of haematologic complications in their second or third decades of life. Others who have mild or no cytopenias survive long enough to develop malignancies. This is a report of a 44-year-old woman who presented with recurrent oral squamous cell carcinoma during her adulthood, without clinical haematological problem. Despite treatment with cis-retinoic acid, she developed a third squamous cell carcinoma 6 months later. In a review of the literature, only in 1 reported case was the patient treated with low-dose retinoids but he developed recurrent anal cancer after 14 months.

Adolescent↗
PubMed1995

Del(3) (p25.3) without phenotypic effect.

A terminal deletion of chromosome 3 at p25.3 was observed during prenatal diagnosis. A similar deletion is also present in the phenotypically normal mother. The deletion was confirmed by FISH. The breakpoint is distal to the region responsible for the 3p- syndrome. A normal baby girl was born with no apparent phenotypic abnormalities.

Adult↗
PubMed1993

Extra G positive band on the long arm of chromosome 9.

Various heteromorphisms of the 9q heterochromatic area have been reported. In most instances, the extra G positive band is accompanied by an extra C band. We describe a family where the extra G band is totally euchromatic and does not include an extra C band. It is not clear whether these two types of variant chromosome 9 arose from a similar mechanism.

Adult↗
PubMed1987

Higher-order factors assessed by the ISI and PRF.

The Interpersonal Style Inventory and the Personality Research Form were administered to 327 adolescents in order to test hypotheses with regard to the second-order factors that they share in common. The 37 scale scores were intercorrelated and factored by the principal axes method and rotated to an oblique solution. The seven correlated factors were interpreted as Impulse Control, Extraversion-Introversion, Autonomy, Level of Socialization, Achievement Motivation, Liking New Experience, and Adventure Seeking. These confirmed four of the hypothesized factors.

Achievement↗
PubMed1982

Multiple karyotypic changes in retinoblastoma tumor cells: presence of normal chromosome No. 13 in most tumors.

There are conflicting reports on the frequency in retinoblastoma tumor cells of aberrations involving chromosome No. 13. To quantitate the frequency of various chromosome aberrations, we analyzed the karyotypes from the retinoblastoma tumors; all tumors contained chromosome abnormalities. Chromosome No. 13 was altered in only two tumors, but the aberrations in these two cases affected different portions of the chromosome. We have concluded that chromosome aberrations affecting chromosome No. 13 are relatively infrequent in retinoblastoma tumors. Chromosome No.1 was involved in rearrangements in eight tumors; in six tumors the rearrangements lead to trisomy of 1q25-1q32. Seven tumors had aberrations resulting in trisomy of the long arm of chromosome No. 17; the most common aberration was an i(17q) chromosome. Every tumor showed trisomy of the long arm of either chromosome No. 1 or 17. These changes in chromosomes No. 1 and 17 have been observed by others in many different tumors and are not unique to retinoblastoma. In summary, chromosome abnormalities were present in all retinoblastoma tumors studied, but no aberration common to all tumors was found.

Animals↗
PubMed1980

Familial retinoblastoma: segregation of chromosome 13 in four families.

Fluorescent markers on chromosome 13 have been used to study familial retinoblastoma. One family showed concordant segregation of a particular chromosome 13 and retinoblastoma from the affected parent to the affected children. In three other families, segregation was discordant. Meiotic crossing over with recombination is proposed as the explanation.

Adult↗
PubMed1979

Absence of chromosome breakage in patients with retinoblastoma.

Mixed lymphocyte cultures were employed to assess the degree of spontaneous chromosome fragility in patients with retinoblastoma. There was no difference between the patients and their controls. If chromosome instability plays a role in the inherited tumour, more sensitive methods need be employed to elucidate it.

Chromosome Aberrations↗
PubMed1975

Reduced lymphocyte transformation in early cancer of the breast.

The cell mediated immune response has been measured in vitro by lymphocyte transformation in 53 patients with malignant tumours of the breast and an equal number of patients in the same age group operated upon for benign tumours. The response to phytohaemagglutinin (PHA) was reduced in the patients with malignant tumours when the lymphocytes were grown either in the patient's plasma or in autologous plasma. This was observed when the response was measured both by the uptake of radioactive DNA precursor and by autoradiography. Reduced lymphocyte transformation was present even very early in the disease and certainly preoperatively. The reduction appeared to be even more marked in the advanced cases. An interesting finding was that the plasma from cancer patients contained a factor which reduced the PHA transformation of lymphocytes from a healthy donor.

Autoradiography↗