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Biomedical subjects

D P Ryan

Publications and source records attributed to D P Ryan.

At least 73 records · Page 4Linked to original sources
PubMed1990

Prevalence of udder bacteria in milk samples from four dairy goat herds.

The prevalence of udder bacterial infections in 4 commercial goat herds in New South Wales was examined. Coagulase negative staphylococci were the predominant bacteria isolated being cultured from 13.3% of the 896 halves tested. Other bacteria isolated were Staphylococcus aureus (less than 1% of halves), streptococci (0.6%) and coliforms (2.0%). The low prevalence of udder bacteria contributing to the contamination of the milk was attributed to the milking management practices carried out in these herds, in particular pre-milking and post-milking antisepsis.

Animals↗
PubMed1990

Validation of the alexithymia construct: a measurement-based approach.

Alexithymia is a hypothetical personality construct that has been associated with a variety of medical and psychiatric disorders. This article reviews a program of research evaluating the validity of the construct using a measurement-based, construct validation approach. For this purpose the Toronto Alexithymia Scale (TAS) was developed. In a series of studies the TAS demonstrated internal consistency, good test-retest reliability, and a stable factor structure theoretically congruent with the alexithymia construct. In separate tests of construct validity, the TAS correlated in a theoretically meaningful fashion with measures of other constructs. Criterion validity was supported by a study in which the TAS was able to discriminate between behavioural medicine outpatients designated as alexithymic and those designated as nonalexithymic on the basis of objectively rated structured interviews. In a normal adult sample, TAS scores were not related to sociodemographic variables or intelligence. These results provide considerable empirical support for the validity of the alexithymia construct. In addition, the TAS appears to be a psychometrically sound measure of alexithymia that may prove useful in testing the construct with psychiatric and medical patient populations.

Adolescent↗
PubMed1989

The first international conference on the Palliative Care of the Elderly: an overview.

The effort to examine and improve palliative care for the elderly is actively joined. In Europe, Scandinavia, and North America, at least, issues are slowly being examined in clinical research. The response to the conference was enthusiastic, and new information emerged, for example: British Columbia's "Levels of Intervention" guidelines, Dr Doyle's description of new developments in Geriatric and Palliative Care training and service in the United Kingdom, Dr Triau et al's (Psychogeriatric Nursing Home, Leuven, Belgium) normalization model of care for dementia, and Dr Rory Fisher's argument that instead of using negative DNR orders in palliative care we should instead take a positive approach of specifying what palliative care can provide. Palliative care is not "no treatment;" increasingly we are able to be concrete and specific in our ability to prescribe a range of measures to ensure that our dying elderly die in comfort and without medical, legal, or social intrusion.

Aged↗
PubMed1988

Duplications of the alimentary tract. Clinical characteristics, preferred treatment, and associated malformations.

Duplications of the alimentary tract are unusual congenital anomalies that frequently present a diagnostic as well as therapeutic challenge to the surgeon. Because these lesions occur so infrequently, they are often not suspected until encountered intraoperatively. Due to the complicated anatomy and common blood supply shared between the duplication and associated native bowel, appropriate management requires a familiarity with the anatomy and clinical characteristics of this entity. To better define the range of patient characteristics, clinical presentation, and preferred therapy, 20 enteric duplications were reviewed in 17 patients treated at the Children's Hospital Medical Center from 1956 to 1986. Ages of patients ranged from 1 day to 11 years; 60% were less than 2 years of age at initial presentation. Seven duplications in six patients involved alimentary tract structures of foregut derivation (esophagus, stomach, and Parts I and II of duodenum), with a predominance of girls (4 of 6). Most of these patients (67%) presented with moderate to severe acute respiratory distress and a mass present on chest radiograph. In 67% of the patients, the correct diagnosis was established before operation. None required emergency operative intervention. By contrast, 13 duplications in 11 patients were of midgut or hindgut derivation (Parts III and IV of the duodenum, jejunum, ileum, and colon). In this group of patients, 62% of the duplications involved the cecum, 23% involved the ileum, and 16%, the jejunum. Seventy-eight per cent of the patients were boys. The most common symptoms were nausea and vomiting, and the most common sign was a palpable abdominal mass. Emergency operative intervention was required of eight of 11 patients with duplications involving the small bowel and colon. Three patients presented with an intussusception, four with signs and symptoms consistent with acute appendicitis, one with a small bowel obstruction, and two with gastrointestinal hemorrhage due to the presence of ectopic gastric mucosa within the duplication. It was found that two important points must be considered in regard to the management of enteric duplications: (1) the common blood supply shared between the duplication and native bowel must be carefully protected to avoid undue sacrifice of normal bowel, and (2) the presence of heterotopic gastric mucosa in 35% of patients negates internal drainage.(ABSTRACT TRUNCATED AT 400 WORDS)

Abnormalities, Multiple↗
PubMed1986

Villous tumors of the duodenum.

Nineteen cases of villous tumors of the duodenum are reported. They have a predilection for the ampullary region, tend to present with obstructive jaundice, especially if malignancy is present, and have a high prevalence of cancer (12 of 19, or 63%). Even when biopsies are available, the diagnosis of cancer is frequently missed (5 of 9 proven cancers, 56% false-negative rate), and it may be impossible to assess the presence of carcinoma in situ or invasive carcinoma without complete excision of the lesion. The authors' experience suggests that some small benign ampullary villous adenomas or those with carcinoma in situ can be excised locally but that pancreaticoduodenectomy is preferable in the fit patient for better local control both of extensive benign lesions and cancers without distant metastases.

Adenoma↗
PubMed1982

The colonization of the Pacific: the story according to human leukocyte antigens.

The human leukocyte antigen (HLA) distributions in 16 Pacific populations have been collated from published and unpublished reports. Gene frequency and linkage disequilibrium relationships among groups show that Australians and Papuans share a common ancestry, that coastal Melanesia has about 16% Austronesian admixture, and that Fiji is truly intermediate between Melanesia and Polynesia. In Polynesia, Cook Islanders show closer affinity with populations of Western Polynesia than with Maoris and Easter Islanders, in contrast to their linguistic affiliations, but otherwise HLA distributions show a clear division between the populations of Eastern and Western Polynesia. This study emphasizes the contribution the HLA system can make to anthropological studies and has provided a version of colonization of the Pacific compatible with theories based on prodigious efforts in many disciplines.

Australia↗
PubMed1981

HLA and non-insulin dependent diabetes in Fiji indians.

HLA frequency distributions in Fiji Indians with non-insulin dependent diabetes were compared with those in control subjects with confirmed two-hour plasma glucose levels less than 7.8 mmol/L. Antigen frequencies at HLA-A and HLA-DR loci were similar in patients and controls. At HLA-B, there was a significant increase in Bw61 (Bw40.2) in diabetics, with a relative risk for this antigen of 4.8. Since a similar finding has been reported previously in South African Indians with Insulin-dependent diabetes, it is possible that wer have defined yet another genetically-distinct form of diabetes, especially prevalent in Indians. Alternatively, definition of new HLA alleles such as Bw61, a new subdivision of an established antigen, may reveal HLA associations with non-insulin dependent diabetes in European Caucasians also.

Adult↗
PubMed1980

HLA studies in Australian multiple-case families of juvenile onset diabetes mellitus.

The pathogenesis of insulin-dependent diabetes mellitus (IDDM) will remain obscure until the number of genetic mechanisms contributing to susceptibility can be clarified. Australian multiple-case families of IDDM have been examined for concordance in IDDM and HLA haplotypes and analysed for goodness-of-fit to hypotheses of one or two high-risk susceptibility genes. Diabetic siblings are HLA-identical in 75% of cases, confirming the association between HLA and IDDM, and suggesting recessively in inheritance of IDDM susceptibility. However, the most striking finding is that 52% of IDDM offspring are positive for both HLA-DRW3 and DRW4, compared with only 8% of their non-diabetic sibs and 1% of the general population. The risk for IDDM for the HLA-DRW3/DRW4 heterozygote is 37.2, and the chance that a child from a multiple-case family of IDDM will himself develop the disease is 6.5 times as great if he is a HLA-DRW3/DRW4 heterozygote than if he is not positive for both antigens. Possible genetic mechanisms are discussed, but the present data strongly support the interaction of two HLA-DR associated susceptibility genes in IDDM and rejects the hypothesis of a single autosomal recessive susceptibility gene.

Australia↗
PubMed1976

Epithelial and surfactant changes in influenzal pulmonary lesions.

Pulmonary epithelial cell destruction in mice infected with PR8-A influenza virus has been studied with light and electron microscopy and enzyme histochemistry, and correlated with pulmonary surfactant activity. All epithelial cell types were infected by the virus, resulting in destruction, pneumonitis, and atelectasis by seven to ten days. Pulmonary surfactant activity decreased progressively following onset of infection, and was minimal by seven to ten days. Before types 1 and 2 alveolar pneumocytes regenerated, the regenerating bronchial cells grew peripherally into some of the denuded alveolar ducts and alveoli to form epithelial nodules. Eventually the types 1 and 2 pneumocytes regenerated to cover the alveolar surfaces that were not invaded by bronchial epithelium. This regeneration was associated with increased surfactant activity in the postinfluenzal lesions, suggesting that the type 2 pneumocytes are a source of surfactant.

Animals↗
PubMed1975

The destruction of type 2 pneumocytes by airborne influenza PR8-A virus; its effect on surfactant and lecithin content of the pneumonic lesions of mice.

Influenzal pneumonia has been studied in mice subjected to sublethal doses of airborne PR8-A influenza virus. Electron microscopy revealed that the virus propagated in and at the same time destroyed the ciliated and nonciliated bronchial cells and the types 1 and 2 alveolar pneumocytes. The regenerating bronchial membranes were metaplastic and grew peripherally into the surrounding alveolar ducts and alveoli to form epithelial nodules which caused obstruction and collapse of the involved lobes. The development of the lung lesions was correlated with phospholipid (lecithin) levels in consolidated and unconsolidated infected and normal lungs. As the lungs became more and more consolidated, there was a corresponding and significant decrease in the amount of phospholipid (dipalmitoyl lecithin) compared to the amount of normal or unconsolidated infected tissue. The destruction of the type 2 pneumocytes by the influenza virus and their failure to regenerate is considered to be the reason for the low phospholipid levels in the involved lobes, and thus an important cause of post-influenzal collapse in mice. The above adds additional evidence to the view that the type 2 pneumocytes are a major source of surfactant in mammalian lungs.

Aerosols↗