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Biomedical subjects

J Hamilton

Publications and source records attributed to J Hamilton.

At least 55 records · Page 3Linked to original sources
PubMed1997

Mandibular invasion in patients with oral and oropharyngeal squamous carcinoma.

Invasion of the mandible in squamous carcinoma of the oral cavity and oropharynx has always proved a problem for head and neck oncologists. We studied 82 patients who had mandibulectomies as part of their primary surgical treatment for cancer of these sites. In 40 patients, the tumour appeared to be invading the mandible on clinical grounds and 33 patients had tumours invading the mandible when the latter was examined histopathologically. Multivariate analysis showed that tumour was more likely to be fixed to and clinically invading the mandible in the presence of cancer of the oral cavity, compared with oropharyngeal cancer (P < 0.0001). There was a high degree of correlation between clinical invasion of the mandible and histopathological invasion of the mandible (P = 0.0059). In addition, clinical invasion of the mandible correlated with radiological findings (P = 0.0284). The 5-year survival of those patients with tumour that appeared not to be invading the mandible was 53% compared with 25% for those where tumour did appear to be invading the mandible (P < 0.02). The sensitivity and specificity of clinical evidence of mandibular invasion was calculated with the final arbiter of invasion being the histopathological findings. The sensitivity of clinical examination was 91% and the specificity 80%. The positive predictive value was 75% and the negative predictive value 93%. Mandibular invasion is a poor prognostic sign in cancer of the oropharynx and oral cavity. Detection of invasion prior to operation is obviously extremely important and it appears that clinical findings are an accurate method of predicting invasion.

Adult↗
PubMed1996

Benzoporphyrin derivative decreases the binding of low density lipoprotein to the glycosaminoglycan chondroitin-6-sulfate in vitro.

We have investigated the effect of the hydrophobic photosensitizer (PS), benzoporphyrin derivative (BPD), on low density lipoprotein (LDL) binding to the glycosaminoglycan (GAG), chondroitin-6-sulfate (C-6-S) in vitro. Agarose electrophoresis of the BPD-LDL complexes indicated that ratios of 50 ng BPD per microgram LDL protein and above displayed increased net negative charge. Ratios less than 10 ng BPD per microgram LDL protein slightly increased the association of the LDL with the C-6-S. Ratios of 10 ng BPD per microgram LDL protein and greater decreased the association between LDL and GAG in a BPD concentration dependent manner. Since the retention of LDL by the extracellular matrix (ECM) GAG in the artery wall is a key event in atherogenesis, the reported effects of BPD on LDL binding to C-6-S may be of interest.

Chondroitin Sulfates↗
PubMed1996

Multicultural health care requires adjustments by doctors and patients.

Canada has become a multicultural society, and more physicians have patients who are immigrants or refugees from the Third World. While doctors are aware of the need for culturally sensitive health care, there is still room for improving the delivery of medical treatment to those of other cultures. Janice Hamilton spoke with physicians who have multicultural practices to get an idea of the challenges they have faced and the problems they have solved.

Attitude to Health↗
PubMed1996

Zoonotic diseases in Canada: an interdisciplinary challenge.

Although zoonotic diseases are generally rare in Canada, a wide range of pathogens can be transmitted from animal reservoirs to humans through insect vectors or direct contact with wild and domestic animals. Across the country researchers with backgrounds ranging from wildlife biology to parasitology and epidemiology are tracking a variety of zoonotic diseases, some of which are causing increasing concern among public health officials.

Animals↗
PubMed1996

McGill makes Canada's first attempt to put medical curriculum in computerized format.

A member of McGill University's Faculty of Medicine wants Canadian medical schools to collaborate to create a central repository for the best teaching materials. Dr. David Fleiszer fears that many individual efforts are being undertaken without an overall plan being in place. For its part, McGill is putting its medical-school curriculum on line over the next 2 years, and is collaborating with industrial partners to develop clinical simulations.

Canada↗
PubMed1996

Signposts to therapy: recent advances in inflammatory bowel disease research.

Research on ulcerative colitis and Crohn disease, the two conditions grouped under the heading of inflammatory bowel disease (IBD), is improving our understanding of how the intestine functions at the cellular level in health and disease. Researchers in the McGill Inflammatory Bowel Disease Research Program are studying the factors that affect the transport of nutrients, salt and water across cell membranes in the intestinal epithelium and investigating the cellular mechanisms of diarrhea. Their main interest is in how the intestine adapts in response to inflammation. Their findings promise to yield new targets for the pharmacologic and dietary management of IBD.

Animals↗
PubMed1996

Electromagnetic interference can cause hospital devices to malfunction, McGill group warns.

Electromagnetic interference (EMI) from sources such as television transmitters, police radios and cellular phones can cause medical monitors and other hospital devices to malfunction, says the principal investigator of a McGill biomedical engineering group set up in 1989 to study, predict and prevent such problems. The impact of equipment malfunction can range from mere inconvenience to serious problems. The research group advises physicians and other health care professionals to learn how to spot problems related to EMI and electromagnetic compatibility.

Electromagnetic Fields↗
PubMed1996

Post-prostatectomy incontinence: urodynamic findings and treatment outcomes.

PURPOSE: We examined urodynamic findings and treatment outcomes in a large population of men with post-prostatectomy incontinence. MATERIALS AND METHODS: A total of 215 men was referred for evaluation and treatment of significant post-prostatectomy incontinence. Urodynamic evaluation consisted of provocation multichannel medium fill cystometry with vigorous attempts to demonstrate incontinence. Treatment was directed by the results of the urodynamic study. A pad scoring system was used to gauge the severity of incontinence before and after treatment. RESULTS: Based on the results of urodynamic studies 40% of the men had genuine stress incontinence alone and approximately 60% had a major component of bladder dysfunction contributing to incontinence. Treatment results of 135 men demonstrated a significant decrease in pad score (p<0.001) for those treated with anticholinergics, those undergoing artificial sphincter insertion and those treated pharmacologically before sphincter placement. CONCLUSIONS: In our large series most men with prostatectomy incontinence did not have genuine stress incontinence alone. Thus, urodynamic studies are critical, not only to define cause of incontinence but to direct effective therapy.

Aged↗
PubMed1996

The national lesbian family study: 1. interviews with prospective mothers.

This first report from a longitudinal study of 84 lesbian families, 70 of which include a co-mother as well as a birthmother whose child was conceived by donor insemination, presents interview data on parental relationships, social supports, pregnancy motives and preferences, stigmatization concerns, and coping strategies. Methodological limitations of studying this special population are noted, and plans for follow-up interviews over the course of 25 years are outlined.

Adaptation, Psychological↗
PubMed1996

Malignant tumours of the cervical oesophagus.

Forty-seven patients with malignancy of the cervical oesophagus are described and compared with a group of 647 patients with hypopharyngeal malignancy. There was a higher proportion of non-squamous malignancy in cervical oesophageal cancer compared with hypopharyngeal cancer. Cervical oesophageal malignancy tended to present earlier with significantly lower T stage and neck node metastases were relatively unusual at presentation. Patients with cervical oesophageal malignancy were frequently incurable at the time they are first seen and 21 had palliative treatment only, 26 patients had curative treatment, 12 underwent radical radiotherapy and 14 had surgery. Cervical oesophageal malignancy had a significantly worse prognosis than hypopharyngeal malignancy with an 18% 3 year survival compared with a 33% 3 year survival (chi (1)2 = 7.1089, P < 0.01). Those patients with oesophageal malignancy who were treated fared considerably better than the whole group with 30% being alive at 3 years (chi (1)2 = 10.5185, P < 0.01).

Carcinoma, Squamous Cell↗
PubMed1996

Raising airway resistance in laryngectomees increases tissue oxygen saturation.

The physiological airflow resistance from the anterior nares to the upper trachea has recently been documented. This resistance is thought to be important in preventing alveolar collapse and in maintaining the optimum lung ventilation: perfusion ratio. This resistance is lost in laryngectomees who may have a subsequent decline in lung function and arterial oxygen saturation. A stoma filter with a resistance approximating to that of the normal upper airway has been developed and laryngectomees who wear this device demonstrate a rapid increase in tissue oxygen saturation (median increase: 1.4 kPa, P = 0.0087) without significantly altering tissue carbon dioxide saturation. This finding will have a major impact on the future rehabilitation of laryngectomees and those with a temporary tracheostomy.

Airway Resistance↗
PubMed1996

Interleukin-11 mRNA stabilization in phorbol ester-stimulated primate bone marrow stromal cells.

12-O-Tetradecanoylphorbol-13-acetate (TPA) stimulation of PU-34 cells, a primate bone marrow stromal cell line, resulted in a prolonged elevation of interleukin-11 (IL-11) mRNA, which can be inhibited by protein synthesis inhibitors. Nuclear run-on assays and actinomycin D experiments demonstrated that the up-regulation of IL-11 gene expression is mainly controlled at the posttranscriptional level through the protein kinase C (PKC) pathway. Inhibition of PKC activity by calphostin C generated an IL-11 mRNA degradation intermediate in TPA-stimulated PU-34 cells. This intermediate retains the 5' untranslated region (5'UTR) and coding region of the IL-11 mRNA but has lost the poly(A) tail and the 3'UTR. The mechanisms underlying IL-11 mRNA stabilization were further investigated by transfections with a variety of chimeric IL-11 constructs and deletion mutants. Two important observations were made from these transient expression experiments: (i) the same 3'UTR of IL-11 mRNA shown to confer instability in one chimeric transcript may not function as a destabilizer in another chimeric RNA, and (ii) the 5'UTR, coding region, and 3'UTR all contribute to IL-11 mRNA decay, and labile IL-11 deletion transcripts are not necessarily stabilized by TPA stimulation. Our study suggests that multiple regions within the IL-11 mRNA are involved in TPA-stimulated IL-11 mRNA stabilization, possibly through a unique RNA folding conformation involving interactions of various RNA sequences within the IL-11 mRNA molecule.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗