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Biomedical subjects

J Mackay

Publications and source records attributed to J Mackay.

At least 73 records · Page 4Linked to original sources
PubMed1996

Tobacco and the developing world.

Tobacco consumption is increasing in developing countries, which will bear the brunt of the tobacco epidemic in the 21st century. If current smoking patterns continue, 7 of the world's 10 million annual deaths from tobacco in 2025 will occur in developing countries. Compared with developed countries, more men and fewer women currently smoke in developing countries, but smoking among girls and women is increasing. While indigenous tobacco production and consumption remain a major problem, of particular concern is the penetration by the transnational tobacco companies, bringing with them denial of the health evidence, sophisticated advertising and promotion, threats of trade sanctions based on tobacco trade, and opposition to tobacco control measures, in particular promotional bans and tobacco tax policy. Developing countries must urgently devise and implement national tobacco control policies, but many governments have little experience in the new noncommunicable disease epidemic or in countering the transnational tobacco companies.

Advertising↗
PubMed1996

Anal pathology in patients with Crohn's disease.

BACKGROUND: A distinctive feature of patients suffering from Crohn's disease is a predisposition to develop a variety of anal complications. The aetiology of such conditions is unclear, and the reported incidence of anal involvement in Crohn's disease varies party due to the various criteria used for classification. This study aims to review the management of patients with symptomatic anal pathology associated with Crohn's disease at St Vincent's Hospital, Melbourne. METHODS: A database of 306 patients with Crohn's disease referred to the department between January 1978 and October 1994 was reviewed to identify those patients with symptomatic anal disease. The anal pathology was recorded and classified. Demographic data and the clinical and surgery history of the patient were recorded. RESULTS: Of the 306 patients with Crohn's disease, 129 (42.4%) were identified as having symptomatic anal pathology. Patients were likely to present with anal symptoms after they had been diagnosed as having intestinal Crohn's disease (46.1%). The commonest presentations were perianal abscess (29.5%), anal fissure (27.6%), and low anal fistula (26.7%). A minority of patients presented with high/complex anal fistulae (3.8%), or recto-vaginal fistulae (5.2%). Five per cent of patients had Crohn's disease localized to the anal area. The pattern of intestinal disease in the remaining patients was small bowel 21.1%. small bowel and colon 31.9%, and colon 43.0%. A total of 244 local anal and surgical procedures were performed on these patients; the commonest of these were drainage of an abscess (38.5%), examination under anaesthetic (29.1%), and laying open of a low anal fistula (22.5%). Following surgical treatment, the recurrence rate for perianal abscesses was 13%, and for low anal fistulae 6%. CONCLUSIONS: The majority of patients with Crohn's disease who develop anal pathology have an excellent prognosis. A minority of patients develop complex anal complex anal fistulae and these remain a therapeutic challenge.

Adult↗
PubMed1996

Conversational perspectives in a communication aid for non-vocal people.

A computer-based text storage and retrieval system (TALK) has recently been developed as a conversation aid for non-vocal people. To facilitate the rapid retrieval (and synthesised speech output) of stored content, potential utterances on each conversational topic are organised according to three intersecting perspectives. The perspectives are "person' (me, you), "time' (past, present, future), and "issue' (what, when, where, who, how, why). Although the system has been shown capable of supporting free-flowing conversation with relatively short pauses preceding the user's turns at speech, the perspective organisation is probably less than ideal for some topics. An experiment was conducted to see whether, over a number of conversational topics, storage and retrieval of potential utterances would be faster with the existing, uniform, set of perspectives or with different sets of perspectives tailored to each topic. At the storage stage, the "uniform' set of perspectives facilitated more rapid classification of potential utterances than the "tailored' sets. At the retrieval stage, however, repetition of the classification decisions was more accurate (without being any slower) for the tailored sets of perspectives, suggesting that retrieval of stored utterances during conversation may be faster when the perspective organisation is tailored to topics.

Adult↗
PubMed1995

Crohn's disease: a colon and rectal department experience.

This study reviewed a series of patients with Crohn's disease managed by surgeons of the Department of Colon and Rectal Surgery, St Vincent's Hospital, Melbourne, since 1978. There were 306 patients: 171 males and 135 females. The mean age at diagnosis was 33.4 years (ranger 11-93). The distribution of the disease was small bowel 32.3%, small bowel and colon 26.5%, colon 39.9%, and anal disease alone 1.6%. A total of 416 abdominal operations were performed on 204 patients. The commonest indications for surgery were failed medical therapy (21.9%), small bowel obstruction (15.9%), enteric fistula (10.1%), and intra-abdominal abscess (10.1%). The most frequently performed procedures were ileocolic resection with anastomosis (28.8%), small bowel resection (9.4%), and total colectomy and ileostomy (7.0%). Postoperative complications included anastomotic leaks in 4.0%, intra-abdominal abscess formation in 3.6%, and enterocutaneous fistulae developed in 6%. Three patients died during the review period. During follow up (mean 84.4), 30% of patients developed recurrence requiring further surgery at a mean of 72.7 months postoperatively. The most frequent site for a recurrence was the pre-anastomotic terminal ileum (61.7%). In conclusion, the majority of patients with Crohn's disease will require resectional surgery at some stage. This can be performed with a low mortality and morbidity, and a recurrence rate of around 5% per year.

Adolescent↗
PubMed1995

Structural changes in the cardiovascular system of untreated essential hypertensives.

Arterial hypertension is associated with structural changes in the cardiovascular system. This study has examined the effect of hypertension on the carotid artery wall and examined the relation between changes in the structure of carotid artery wall and left ventricle in untreated hypertensives. The carotid artery wall was visualized using a high resolution ultrasound technique in 37 untreated hypertensive patients (25 males, 12 females) and 37 age and sex matched normotensive individuals and carotid intima-media thickness (IMT) and carotid artery diameter measured. IMT and intima-media cross sectional area was significantly greater in the hypertensive group compared with the normotensive group, though the carotid artery diameter did not differ significantly. There was a significant association between age and IMT in both groups. In the hypertensive group there was also a significant association between left ventricular mass index, ventricular septal or posterior wall thickness and IMT. This study indicates that there is an association between cardiac and carotid arterial structure in hypertension. Such a relationship may be important in understanding the associated risks of high blood pressure.

Adult↗
PubMed1995

Loss of heterozygosity at 11q22 correlates with low progesterone receptor content in epithelial ovarian cancer.

Forty-seven epithelial ovarian cancers were analyzed for loss of heterozygosity (LOH) at D11S35 (11q22), close to the progesterone receptor (PR) gene, and for tumoral estrogen receptor (ER) and PR content. Thirty-eight of 47 tumors were informative, and, of these, 14 exhibited LOH. There was a significant association (P = 0.014) between D11S35 LOH and low tumoral PR content. For all informative tumors, there was no correlation between ER and PR; however, exclusion of tumors with LOH from the informative series revealed a linear correlation between tumoral ER and PR (P = 0.013), and established ER (P = 0.025) and PR (P = 0.05) content as significant factors in relation to patient survival. Patients with ER-rich tumors with D11S35 LOH had particularly poor survival compared with ER-rich, D11S35 heterozygous, no loss patients (P = 0.014). Analysis of the same tumors using two other microsatellites, D11S935 (11p13) and NM23 (17q22), showed no statistically significant relationships, although there were nonsignificant trends for the correlation of ER and PR expression in informative tumors without allele loss at these loci. We propose that genomic structural alteration at or close to the PR gene locus has biological and clinical sequelae in ovarian cancer.

Chromosomes, Human, Pair 11↗
PubMed1994

The tobacco problem: commercial profit versus health--the conflict of interests in developing countries.

As smoking gradually decreases in developed countries, the tobacco epidemic is overtaking developing countries, where the legislative controls and other measures, which in industrialised countries succeed in limiting tobacco use, either do not exist or are, at best, inadequate. Of particular concern is the penetration of developing countries by the transnational tobacco companies, who with aggressive promotional campaigns and the use of political and commercial pressures, open up markets to promote foreign cigarettes. The number of smokers in developing countries will inevitably increase, due to the rise in population, increased smoking among youth and women, lack of awareness of the harmfulness of tobacco, shortage of funding for tobacco control measures, and difficulties in implementing legislation. An appalling increase is predicted in disease, disability, and death from tobacco in developing countries. Developing countries must exercise their own public health responsibility and implement measures to reduce the growing tobacco epidemic. Health concerns in Western countries can assist by bringing these issues to public and government attention in order to ensure that transnational tobacco companies, at minimum, adhere to the same standards of product, marketing, promotion, and sales in developing countries as are required in their country of origin; that these tobacco companies should desist from lobbying and pressuring the governments of developing countries to prevent the passing and implementing of antitobacco measures; that the United States and UK governments desist from helping their tobacco companies with export activities; and that Western expertise in countering the tobacco epidemic be shared with developing countries so that the West becomes an exporter of health rather than of tobacco-related diseases.

Adolescent↗
PubMed1993

The peri-operative management of surgical insertion and removal of the intravenous oxygenator device (IVOX). A report of nine cases.

Intravenous oxygenation (IVOX) is a new technique for augmentation of gas exchange in patients who require near maximal conventional ventilatory support. Patients who require IVOX are, by definition, critically ill with a high expected mortality. At present, these high risk patients must be transferred to the operating theatre for the IVOX device to be inserted. This report describes the anaesthetic problems associated with nine patients in whom an IVOX device was inserted and removed in our institution. The mortality was six out of nine patients; all deaths occurred with the IVOX device in situ. Three patients died within 6 h of insertion. Four patients were female. The patients' ages ranged from 14 to 76 years. There were few immediate ventilation changes in the first 4 h after IVOX insertion. Inspired oxygenation concentration was reduced in only one patient. Positive end-expiratory pressure was not reduced. Peak inspiratory pressure decreased in four patients. Arterial oxygen tension increased in four patients (range 0.1-2.5 kPa) and decreased in five (range 0.1-3.4 kPa). Arterial carbon dioxide tension increased in one patient (0.3 kPa) and decreased in eight (range 0.1-2.7 kPa). Inotropic support with adrenaline, dobutamine and noradrenaline needed to be initiated or increased in eight patients. Eight patients required 2-4 units of blood to be transfused during IVOX insertion or in the following 2 h. One patient suffered an asystolic cardiac arrest during the operation, but was resuscitated successfully. Three patients survived to have the IVOX removed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Laparostomy: a technique for the management of severe abdominal sepsis.

The mortality from acute suppurative peritonitis may approach 70%, survivors often undergoing multiple operations and requiring protracted intensive medical support. Attempts to improve prognosis fail when they rely on the diagnosis of persistent or recurrent collections. The results of laparostomy in conjunction with continuous peritoneal irrigation (CPI), which aims to primarily eradicate and subsequently prevent the recurrence of sepsis are reported. Two deaths occurred in this series of seven patients, only one attributed to persistent sepsis. Overall, the mortality of 28% compares favourably with similar patient series and suggests that laparostomy with CPI deserves consideration in the management of selected patients with severely contaminated abdominal cavities.

Acute Disease↗
PubMed1993

Structural changes in the heart and carotid arteries associated with hypertension in humans.

Hypertension is associated with structural changes in the vascular system and in the heart. This study has examined the relationships between carotid artery intima-media thickness and other risk factors in 52 untreated patients (20 hypertensive). Carotid intima-media thickness was measured bilaterally using a Duplex doppler ultrasonic scanner. In the hypertensive individuals the left ventricle was examined by echo-cardiography and the left ventricular mass index determined. There was a significant association between age and IMT, and both SBP and DBP and IMT. The IMT in the hypertensive group was significantly larger than in the normotensive group and in the hypertensive subjects there was a positive association between left ventricular mass index and IMT. There was no significant difference in calculated media stress between the normotensive and hypertensive groups, probably due to a small increase in carotid intima-media area combined with a small reduction in carotid lumen diameter. Hypertension is associated with a thickening of the intima-media of the carotid artery and an increase in left ventricular mass. Whether these changes in cardiac and arterial structure are in response to similar influences remains to be established.

Adolescent↗
PubMed1992

US tobacco export to Third World: Third World War.

Global tobacco-related mortality will rise from the current 2.5 million to over 10 million annually by 2050. Most of this increase will occur in developing countries, where legislative controls and other measures that succeed in limiting the use of tobacco in industrialized countries do not exist or are at best inadequate. Of particular concern is the penetration of developing countries by the transnational tobacco companies, with aggressive promotional campaigns that include specific targeting of women, few of whom currently smoke in developing countries. The transnational tobacco companies advertise and market in ways long banned in the United States, for example, selling cigarettes without health warnings, advertising on television, and selling cigarettes with higher tar content than the same cigarettes sold in the United States. Also, tobacco advertising revenue prevents the media from reporting on the hazards of tobacco, a particularly serious problem in developing countries, where awareness of the harmfulness of tobacco is low. The transnational tobacco companies interfere with the national public health laws of developing countries via political and commercial pressures to open markets and to promote foreign cigarettes. This has led to an increase in market share by foreign cigarettes, but evidence also points to market expansion, especially among young people. The entry of the transnationals leads to a collapse of national tobacco monopolies or to their changing from unsophisticated government departments that may still cooperate with health initiatives on tobacco to copying the aggressive marketing and promotional behavior of the transnationals.(ABSTRACT TRUNCATED AT 250 WORDS)

Commerce↗
PubMed1991

Assessing community interventions to reduce smoking.

Few major, community-based antismoking programs have undergone specific evaluation in developed countries; the number is even lower in developing countries. Yet not all evaluation need be elaborate, expensive, or overly time-consuming. Data on tobacco trade, import and export, taxation, mortality, and morbidity may already exist within government departments and can be used for evaluation. Published information from the tobacco industry may be obtained easily in trade journals and annual reports. Universities and international and overseas national health agencies may offer information, assistance, and expertise. Indirect evaluation of the importance of any particular antismoking intervention can be measured by how strongly the tobacco industry opposes that measure.

Community Participation↗
PubMed1991

Adenoma-carcinoma sequence of the large bowel.

Fifty-two surgically removed large bowel specimens and 3 colonoscopically removed polyps with mucosal carcinomas were studied. Among 36 frank colorectal carcinomas, six (17%) had a focus of adenomatous remnant. The average size of carcinomas without adenomatous remnant was 56.0 mm and of those with adenomatous remnant was 44.3 mm. Four (67%) of 6 submucosal carcinomas and all of 4 mucosal carcinomas showed an adenomatous remnant. The average size of submucosal carcinomas was 17.7 mm and that of mucosal carcinomas was 16.3 mm. The smaller and less advanced the carcinoma, the more likely it was to show an adenomatous remnant, suggesting that carcinomas arise in adenomas and destroy surviving benign tumour as they grow. Coexisting adenomas were seen in 19 of 46 neoplasm-bearing patients (41%) and 1 of 9 patients (11%) without neoplasms. Average sizes of adenomas with moderate and mild atypia were 13.0 mm and 8.2 mm respectively, which were smaller than the sizes of submucosal and mucosal carcinomas. Although the numbers were small, these findings support the concept of adenoma-carcinoma sequence. Twenty-one flat elevations were collected during the study. Ten were neoplasm (9 adenomas and an early carcinoma), ten were metaplastic polyps and one was a histologically normal mucosal protrusion. The atypism of 10 flat adenomas increased with increasing size, as with ordinary adenomas. As 10 of 55 adenomas (18.2%) were flat adenomas, which are difficult to detect during routine colonoscopic examination, colonoscopists should make every effort to discover flat adenomas, which seem to play an important role in the adenoma-carcinoma sequence.

Adenoma↗
PubMed1990

Evidence implicating at least two genes on chromosome 17p in breast carcinogenesis.

The DNA of paired tumour and blood leucocyte samples from a large series of breast cancer patients was analysed to map regions of loss of heterozygosity on chromosome 17. The high frequency of loss of heterozygosity on 17p was confirmed, and a third of informative tumours had also lost an allele at the long arm locus THH59. On the short arm two distinct regions of loss of heterozygosity were identified, in bands p13-3 and p13-1. The latter probably involves the structural gene p53, which has been implicated as an oncogene or as a tumour suppressor in various human cancers. 17p 13-3, however, showed a significantly higher frequency of loss of heterozygosity, and there was no correlation between allele losses at the two sites. Nevertheless, loss of heterozygosity at 17p 13-3 is associated with overexpression of p53 mRNA, suggesting the existence of a gene some 20 megabases telomeric of p53 that regulates its expression. Lesions of this regulatory gene seem to be involved in the majority of breast cancers.

Alleles↗