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Biomedical subjects

J Mackay

Publications and source records attributed to J Mackay.

At least 37 records · Page 2Linked to original sources
PubMed1999

Transcriptional cofactors of the FOG family interact with GATA proteins by means of multiple zinc fingers.

Friend of GATA-1 (FOG-1) is a zinc finger protein that has been shown to interact physically with the erythroid DNA-binding protein GATA-1 and modulate its transcriptional activity. Recently, two new members of the FOG family have been identified: a mammalian protein, FOG-2, that also associates with GATA-1 and other mammalian GATA factors; and U-shaped, a Drosophila protein that interacts with the Drosophila GATA protein Pannier. FOG proteins contain multiple zinc fingers and it has been shown previously that the sixth finger of FOG-1 interacts specifically with the N-finger but not the C-finger of GATA-1. Here we show that fingers 1, 5 and 9 of FOG-1 also interact with the N-finger of GATA-1 and that FOG-2 and U-shaped also contain multiple GATA-interacting fingers. We define the key contact residues and show that these residues are highly conserved in GATA-interacting fingers. We examine the effect of selectively mutating the four interacting fingers of FOG-1 and show that each contributes to FOG-1's ability to modulate GATA-1 activity. Finally, we show that FOG-1 can repress GATA-1-mediated activation and present evidence that this ability involves the recently described CtBP co-repressor proteins that recognize all known FOG proteins.

Alcohol Oxidoreductases↗
PubMed1999

Intestinal sleeve anastomosis: a comparative study with end-to-end anastomosis.

This study examines the utility of a sleeve anastomosis with comparison to conventional end to end anastomosis. Thirty New Zealand white rabbits were randomized to sleeve (n = 15) or end-to-end (n = 15) small bowel anastomosis. Five rabbits of each group were sacrificed at 3 days, 7 days, and 6 weeks. Anastomoses were assessed for integrity, bursting strength, and stenosis and examined histologically. Ten control specimens of small bowel were tested for bursting pressure. Three rabbits died postoperatively (1 sleeve and 2 end-to-end). A fourth rabbit (sleeve) was sacrificed early at 3 weeks and had a total stenosis at the anastomosis. The remaining 26 rabbits were reoperated at the prescribed times. There was no evidence of infection or dehiscence in any of these rabbits. Both end-to-end and sleeve anastomoses were equivalent for bursting pressure at all times and, at 7 days and 6 weeks, were similar to controls. The stenotic index revealed no evidence of proximal dilation suggestive of obstruction in the 26 rabbits. For sleeve anastomoses the length of the projected bowel into the lumen persisted at the 6-week stage. Histologically there was good evidence of healing in both the sleeve and end-to-end anstomoses and the serosal surface of the sleeved bowel had epithelialized. Sleeve anastomosis has been demonstrated to heal well and to be as strong as conventional end-to-end anastomosis. Further studies are warranted to determine its role in intestinal anastomosis and potential as a valve.

Anastomosis, Surgical↗
PubMed1999

The impact of genetic counselling about breast cancer risk on women's risk perceptions and levels of distress.

Women referred to a familial breast cancer clinic completed questionnaires before and after counselling and at annual follow-up to assess their risk estimate and psychological characteristics. The aims were to determine whether those who attended the clinic overestimated their risk or were highly anxious and whether counselling influenced risk estimates and levels of distress. Women (n = 450) at this clinic were more likely to underestimate (39%) than overestimate (14%) their risk. Mean trait anxiety scores were higher than general population data (t = 4.9, n = 1059, P<0.001) but not significantly different from published data from other screening samples. Overestimators (z = 5.69, P<0.0001) and underestimators (z = -8.01, P<0.0001) reported significantly different risk estimates (i.e. increased accuracy) after counselling, but significant inaccuracies persisted. Over- (n = 12) and underestimators (n = 60) were still inaccurate in their risk estimates by a factor of 2 after counselling. Thirty per cent of the sample scored above the cut-off (5/6) for case identification on a screening measure for psychological distress, the General Health Questionnaire (GHQ). GHQ scores were significantly lower after counselling (t = 3.6, d.f. = 384, P = 0.0004) with no evidence of increasing risk estimate causing increased distress. The risk of distress after counselling was greater for younger women and those who were more distressed at first presentation. The counselling offered was effective in increasing the accuracy of risk perceptions without causing distress to those who initially underestimated their risk. It is worrying that inaccuracies persisted, particularly as the demand for service has since reduced the consultation time offered in this clinic. Further work is needed to evaluate alternative models of service delivery using more sophisticated methods of assessing understanding of risk.

Adult↗
PubMed1999

Total colectomy for Crohn's disease.

BACKGROUND: Total colectomy for Crohn's disease of the colon may be restorative with ileorectal anastomosis or with an ileostomy and rectal stump. The present paper retrospectively audits the results of total colectomy and in particular assesses the number of patients who had a permanent ileostomy and whether this was related to disease in the rectum at the time of the original operation. METHODS: A retrospective case note review was undertaken of patients operated upon between 1968 and 1994. RESULTS: Thirty-eight patients were identified (mean age 35 years; range 17-65 years). One patient died perioperatively from an anastomotic leak. Median follow-up for the remaining patients was 7 years (range 1-29 years). Ileorectal anastomosis was performed in 17 patients and total colectomy and ileostomy in 20 patients. Indications for surgery were failure of medical treatment (61%); toxic colitis (18%); abscess (8%); perforation (5%); large bowel obstruction (5%); and colovesical fistula (3%). Subsequent proctectomy (14 patients, 38%) was more likely with subtotal colectomy and ileostomy (nine patients, 45%) than ileorectal anastomosis (five patients, 29%). This was not statistically significant (P = 0.33). Additionally, seven patients had diversion of the rectum making 21 with an ileostomy (57%). Rectal involvement at the time of the original procedure significantly increased the likelihood of permanent ileostomy (P = 0.001). The presence of anal disease did not increase the prospect of ileostomy. One patient died with advanced adeno carcinoma in a defunctioned rectum. CONCLUSIONS: A permanent ileostomy after total colectomy for Crohn's disease is common and significantly more likely with rectal involvement.

Adolescent↗
PubMed1998

The use of videotaped information in cancer genetic counselling: a randomized evaluation study.

A video of introductory information about inherited susceptibility to breast cancer was made in consultation with clinicians in four Scottish cancer family clinics. One hundred and twenty-eight women, newly referred for breast cancer risk counselling were randomized to receive the video before (n = 66) or after (n = 62) counselling. Data were collected before randomization at clinic and by postal follow-up at 1 month. The Video Before group had shorter consultations with the breast surgeon (mean = 11.8 min+/-5.4 vs 14.6+/-7.2 for the Video After group). There was no difference between the groups in the accuracy of their risk estimate after counselling, although the Video Before group scored higher for self-reported (Z= 3.65, d.f. = 1, P < 0.01) and objectively assessed understanding (Z= 2.91, d.f. = 1, P < 0.01). At 1 month follow-up, the Video Before group were less likely to underestimate their risk estimate (38% vs 18%; chi2 = 4.62, d.f. = 1, P< 0.05), but there was then no difference between the groups in subjective or objective understanding. Use of the video was not associated with increased distress (GHQ, Spielberger State Anxiety) and was associated with greater satisfaction with the information given at the clinic. This study supports the value of videotape as a method of giving information to prepare women for breast cancer risk counselling. Observations of misunderstandings and distress emphasize the video should be seen as an aid to, not a substitute, for communications at the clinic.

Adult↗
PubMed1998

Screening for breast and ovarian cancer: the relevance of family history.

The recent identification of two breast and ovarian cancer susceptibility genes--BRCA1 and BRCA2--has received a lot of publicity. Public and professional expectations of the availability and utility of genetic testing have been raised and the importance of a family history of breast cancer overemphasized. In this chapter, we examine the significance of a family history of breast or ovarian cancer in determining individual risk. A strategy for management is proposed, based on stratifying women with such a history into three different categories of risk for breast cancer: high, moderate and low. Some of the more controversial aspects of screening for breast and ovarian cancer are reviewed, including the issue of management of women who are at increased risk of these cancers by virtue of a family history, genetic predisposition, or both. There is a need for further research to clarify the most appropriate management of those at moderate risk of developing these cancers. A management strategy for women at high risk is proposed. We believe that adoption of this strategy will strengthen consistent information giving from primary to tertiary care.

Breast Neoplasms↗
PubMed1997

BRCA1 5382insC mutation in sporadic and familial breast and ovarian carcinoma in Scotland.

A restriction site-generating polymerase chain reaction (RG-PCR) assay was developed to detect the BRCA1 5382insC mutation that has been reported in multiple, apparently unrelated breast/ovarian carcinoma families. The assay has been used to screen tumour DNA from 250 breast cancer patients (aged 19-86 years) and from 80 ovarian cancer patients (aged 25-90 years) in a local population of patients with no known family history. Altogether, 0/80 (0%) ovarian and 1/250 (0.4%) breast tumour DNAs were found to have the 5382insC mutation. The sole positive case was a 26-year-old woman (BC185) with no known family history. One of the reasons for carrying out this analysis was that the 5382insC mutation had previously been shown to segregate with the disease in a very large Scottish 'West Lothian' kindred having breast/ovarian carcinoma. To investigate whether this apparently isolated case and the known family might be related, haplotypes for the markers D17S855, D17S1322, D17S1323 and D17S1327 were analysed. The mutant haplotype in the large kindred was identical to that reported in all other 5382insC mutation families for all markers with the exception of D17S1327. This implies that there has been a recombination event at the telomeric end of common ancestral haplotype in this family. Since the isolated case we identified carries the 'complete' common haplotype, it is unlikely that she is closely related to the West Lothian family.

Adult↗
PubMed1997

Industrial Genotoxicology Group collaborative trial to investigate cell cycle parameters in human lymphocyte cytogenetics studies.

Human lymphocyte cultures have been used for many years for assessing the in vitro clastogenic potential of test substances. In these assays the harvest time should be based on the cell cycle time in order to ensure that cells are sampled at an appropriate time for the detection of clastogenic effects. The sources of variation in the cell cycle time in routine cytogenetic assays have not been well studied. Consequently 13 laboratories, all members of the Industrial Genotoxicology Group, participated in a collaborative study to measure the variation in cell cycle time in cultured human peripheral blood lymphocytes under various conditions. The study was performed in two phases, spaced 6 months apart. The average generation time (AGT) was measured by the incorporation of bromodeoxyuridine. Very similar AGTs were found in the presence and absence of S9 mix. The mean AGT (mean of four donors) in each laboratory varied from 11.2 to 17.1 h, indicating there is significant variability in cell cycle times of human peripheral blood lymphocytes between laboratories. There was greater variation between laboratories than within laboratories. A comparison of AGT values at 72 h performed in experiments at least 6 months apart indicated good reproducibility in most laboratories. The study indicates that a 24 h post-treatment harvest may result in the analysis of very few first division cells unless very significant cell cycle delay is induced by the test substance. It was also found that a post-harvest time equivalent to 1.5 cell cycles will result in an approximately equal mixture of first and second division cells and therefore should by suitable for assessing both the induction of chromosome aberrations and polyploidy.

Animals↗
PubMed1997

Pre-operative radiotherapy and chemotherapy for non-resectable rectal cancer.

BACKGROUND: The treatment results of combined pre-operative radiotherapy and chemotherapy followed by surgery for patients with initially non-resectable primary rectal cancer were reviewed. METHODS: Thirteen patients with locally advanced non-resectable rectal cancer were treated with pre-operative irradiation consisting of 50.4-54 Gy plus concomitant 5-fluorouracil (5-FU) delivered during the 1st and 5th weeks of radiotherapy. RESULTS: Following pre-operative therapy, the resectability rate was 91%, with all but one patient undergoing complete resection. The pathologic complete response rate was 10%. The overall peri-operative and postoperative complication rate was 0.8 complications per patient. There was no postoperative mortality. CONCLUSIONS: This early experience indicates that high resectability rates are achievable with pre-operative radiotherapy and chemotherapy for non-resectable rectal cancer while maintaining acceptable postoperative morbidity.

Aged↗