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Biomedical subjects

M Stuart

Publications and source records attributed to M Stuart.

At least 73 records · Page 4Linked to original sources
PubMed1987

Effect of size and lipid composition on the pharmacokinetics of intravitreal liposomes.

We investigated the influence of size and lipid composition on the pharmacokinetic behavior of liposomes and their contents in the rabbit eye. Small and large unilamellar vesicles (SUV and LUV), prepared with and without cholesterol in the membrane, were injected intravitreally in rabbits. The vesicles were labelled with 125I and contained 51Cr-EDTA in the aqueous compartment. The mode of elimination of the vesicles from the vitreous humor is uncertain but may be via the anterior route; 51Cr-EDTA, like gentamicin, probably is eliminated by the anterior route. The rate of clearance of the lipid label appeared to be related to the size but not to the cholesterol content of the liposomes. Liposome-encapsulation prolonged the half-life of 51Cr-EDTA by up to 11-fold in the vitreous humor of normal eyes. The prolongation was greatest with cholesterol-containing vesicles, presumably because these are most stable, and was somewhat greater with large than with small vesicles. For SUV and LUV, the rate of elimination of 51Cr-EDTA from the normal eye was determined mainly by the rate of leakage from the liposomes, whereas for SUV-cholesterol and LUV-cholesterol, it was determined mainly by the rate of clearance of the liposomes themselves. Both 51Cr-EDTA and liposomes (125I label) had a shorter half-life in infected than in normal eyes. Encapsulation of 51Cr-EDTA prolonged its half-life by up to sevenfold in infected eyes; the effect was greatest with cholesterol-containing vesicles. These results suggest that both the structure of the liposome and the state of the eye may markedly affect the pharmacokinetic behavior of intravitreal liposomes.

Animals↗
PubMed1986

Breast-feeding the premature infant.

Although some controversy persists regarding the nutritional adequacy of breast milk for the very low birth weight infant, most authorities agree that milk expressed from the infant's biologic mother and fortified with additional minerals and protein is a proper source of nutrition. Proper support of the preterm infant and mother during expression of breast milk and during the transition to nursing requires a broad knowledge base and familiarity with the practical aspects of breast-feeding.

Breast Feeding↗
PubMed1984

Pneumatosis coli complicating carcinoma of the colon. Report of a case.

The management of pneumatosis coli by oxygen therapy is now well established. In one of five patients treated by this method, routine colonoscopy after such therapy revealed a previously unsuspected carcinoma of the sigmoid colon. The need to thoroughly examine the colon after oxygen treatment to rule out coexistent pathologic conditions is emphasized.

Aged↗
PubMed1984

Proctitis cystica profunda. Incidence, etiology, and treatment.

Proctitis cystica profunda is an uncommon benign rectal condition with a range of appearances that has led to confusion in nomenclature. In a personal series of 28 patients with histologically proven proctitis cystica profunda, over 50 per cent had associated rectal prolapse. Cure of the prolapse cured the proctitis cystica profunda in 80 per cent of the patients only. Direct surgical excision (local or segmental) has not been successful and two patients have required a stoma for relief of pain.

Adolescent↗
PubMed1984

The evaluation of imprecision in collaborative immunoassay quality-assessment programmes.

The calculation of within-laboratory imprecision in quality-assessment (QA) programmes normally involves combining data from different analyte concentrations to calculate an average standard deviation (SD) or coefficient of variation. However, for immunoassay neither of these parameters is concentration independent. This paper describes a method of calculating within-laboratory imprecision in QA programmes by assuming a linear relationship between SD and analyte concentration. This method is used in programmes conducted by the Australian Joint Working Party for Quality Control in Immunoassay to calculate imprecision at the limits of the reference range. Results from these programmes show that this method better represents the differences in imprecision between analytes, methods and laboratories than the calculation of a single imprecision parameter. The method is trivial for a computer and its robustness has been validated by Monte Carlo simulation. It is suggested that major differences in laboratory performance between different QA programmes may be due to inappropriate calculation of single imprecision parameters.

Humans↗
PubMed1982

Serum concentrations of calcium and vitamin D metabolites in prosimians.

The concentrations of total calcium, 25-hydroxyvitamin D [25-(OH)D] and 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] were measured in serum obtained from prosimians, the brown lemurs. The mean serum calcium level was 10.6 mg/dl in male and female lemurs. The mean serum mean 25-(OH)D concentration in serum from male and female lemurs was 27.1 and 31.0 ng/ml, respectively. The mean serum level of 1,25-(OH)2D3 in the female and male lemurs was 65.2 and 65.9 pg/ml, respectively. A small segment of the lemurs had hypercalcemia and elevated serum concentrations of 25-(OH)D or 1,25-(OH)2D3, suggesting the idea that the episodic ingestion of a large quantity of the calcium- and vitamin D-enriched diet normally provided ad libitum might cause hypercalcemia.

Animals↗
PubMed1981

Hemoccult II test: routine screening procedure for colorectal neoplasm?

In October, 1978, the Hemoccult II Test was introduced as a screening procedure by the Sydney Hospital Heath Information and Screening Service. In the first two years, 4498 people were screened and 150 positive results were obtained. These people were referred for further investigation, with 114 choosing to attend the Edward Wilson Colon and Rectum Unit outpatient clinic at Sydney Hospital. Forty-four patients were found to have 59 colorectal neoplasms of which 13 were carcinomas. This represents a cancer incidence of 0.29% and corroborates the results of similar studies conducted overseas.

Australia↗
PubMed1980

Irradiation injuries of the large intestine.

A series of 15 patients suffering from irradiation injuries to the large bowel is reviewed. Ten patients required surgical intervention, initially a diverting stoma in eight; intestinal continuity was re-established in three patients. Loop ileostomy may be preferable to loop transverse colostomy for fecal diversion, as the former is easier for the patient to manage, and ensures that there is no interference with blood supply to the colon should an abdomino-anal pull-through procedure be indicated later to restore continuity. As only three of the patients developed recurrent carcinoma, the initial operation for irradiation injury to the large bowel should be carefully planned so that the patient is not ultimately cured of carcinoma but left with a permanent stoma.

Aged↗
PubMed1980

Lymphatic cyst of the descending colon: a report of a case.

A patient with a lymphatic cyst of the descending colon, treated by segmental colon resection, is reported. Lymphatic cysts of the colon are extremely rare, and there have been only fourteen previously reported cases. In no case has the diagnosis of lymphatic cyst of the colon been made prior to the excision of the lesion.

Aged↗
PubMed1979

Fibreoptic colonoscopy. Indications, results and complications.

Fibreoptic colonoscopy was commenced in the Edward Wilson Colon and Rectum Unit at Sydney Hospital in June, 1973. The experience of the first five years of its use is reported. Six hundred and twenty-six examinations have been performed in 568 patients. Fibreoptic colonoscopy has been of particular value in the diagnosis and treatment of colonic polyps. A total of 318 polyps were removed from 184 patients. Their distribution, size and histological features are recorded. Eight complications occurred in the 628 examinations (1.6%). There were six colonic perforations (1.2%) with one death, and two significant haemorrhages (0.4%). This incidence of complications is acceptably low, especially in view of the great benefits obtained by the patient from fibreoptic colonoscopy. The newer instruments, especially the medium length Olympus MB3 colonoscope, have greatly facilitated the examination and, combined with increasing experience, may significantly lower the incidence of complications in the future.

Adolescent↗
PubMed1979

Peritoneal nocardiosis: report of a case.

A case of primary peritoneal nocardiosis is presented. The patient died, despite prompt, aggressive and appropriate antibiotic therapy. Decreased patient resistance is suggested as the cause of the overwhelming nature of the infection in this case. The importance of administering prophylactic antibiotics on a long-term basis to prevent recurrence after successful treatment is stressed. Although nocardial infections are rare, they may become more common because of the current widespread use of immunosuppressive therapy.

Anti-Bacterial Agents↗
PubMed1979

Elective resection for diverticular disease.

A series of 119 patients undergoing elective resection for diverticular disease has been reviewed. The indications for resection were classified into two major groups--those with severe infections ("complicated" diverticulitis), comprising 58 patients, and those with minimal infections, comprising 61 patients. The majority of the resections were limited to the sigmoid colon (101 patients). Fifteen patients underwent left hemicolectomy, whilst three had total colectomy. Thirty-six patients (30%) had a proximal defunctioning stoma--18 prior to resection and 19 at the time of resection. Anastomotic defects were noted in 15 patients (12.6%), but these were of clinical significance only in eight (6.7%). There were two deaths (1.7%) and 17 wound infections (14.3%). The group classified as "complicated" diverticulitis included the great majority of the patients requiring colostomy (32 out of 37), almost all those with anastomotic defects (14 out of 15), and most of the patients who had postoperative complications.

Acute Disease↗
PubMed1979

Rectal prolapse.

One hundred and twenty-seven patients with complete rectal prolapse have been reviewed. The condition occurred more commonly in females than males (105 to 22), and at an older age in females (mean age 55 years compared with 40 years for males). Although the diagnosis is usually obvious, the importance of recognizing occult prolapse is stressed, especially in association with benign rectal ulcer, localized proctitis and colitis cystica profunda. Examination of the patient in the squatting position may assit in showing occult prolapse. Associated incontinence occurred in 33 patients (26%). Since 1971 the policy of this Unit has been to perform a Ripstein repair for complete rectal prolapse wherever possible. One hundred and two Ripstein repairs have not been performed. A minimum follow-up period of two years is available for 53 patients, of whom 50 (94%) have had their prolapse cured. Control of prolapse usually improves continence; however, seven (13%) remained incontinent despite surgery. The Ripstein repair is strongly advocated as the most effective operation for cure of complete rectal prolapse.

Adolescent↗
PubMed1979

Ileostomy reconstruction.

A study of 47 patients undergoing ileostomy reconstruction is presented. The most common indications were recession (15 patients) and a desire for a continent type of ileostomy (12 patients). Less frequent indications were stenosis (6 patients), parastomal ulceration (6 patients), prolapse (4 patients), unsatisfactory siting (3 patients), and parastomal hernia (1 patient). Refashioning of the ileostomy at the same site was possible in 17 patients, whilst repositioning at a new site was required in 30 cases. In 28 of these laparotomy was carried out to enable repositioning, but in two cases resiting was performed without laparotomy. After the original operation, reconstruction may become necessary at any time from a few months to over 20 years.

Adolescent↗
PubMed1979

The surgical treatment of anal incontinence.

This study is review of 31 patients undergoing surgery for anal incontinence. Three groups of patients are defined--those with incontinence due to trauma (nine patients), to a combination of trauma and degeneration (five patients), and to degeneration alone (17 patients). Two surgical techniques were used--either a direct repair of the anal sphincter or a postanal repair of the levator ani muscles and external sphincter (Parks operation). In the trauma group and the combined group the more common method used was a direct repair (ten patients)--five underwent a Parks operation. In the degeneration group all but one patient underwent a Parks operation. A defunctioning proximal colostomy was carried out in only four patients--all with incontinence due to trauma. Satisfactory continence was restored in 80% of these patients. Although this is a small series, the results are considered worthwhile and greater awareness and use of the above technique is recommended.

Adult↗