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Biomedical subjects

P Sheehan

Publications and source records attributed to P Sheehan.

At least 19 recordsLinked to original sources
PubMed2003

Is there a relationship between soil and groundwater toxicity?

Part IIA of the Environmental Protection Act 1990 requires environmental regulators to assess the risk of contaminants leaching from soils into groundwater (DETR, 1999). This newly introduced legislation assumes a link between soil and groundwater chemistry, in which rainwater leaches contaminants from soil into the saturated zone. As the toxicity of both groundwater and overlying soils is dependent upon the chemicals present, their partitioning and their bioavailability, similar patterns of soil, leachates and groundwater toxicity should be observed at contaminated sites. Soil and groundwater samples were collected from different contaminated land sites in an urban area, and used to determine relationships between soil chemistry and toxicity, mobility of contaminants, and groundwater chemistry and toxicity. Soils were leached using water to mimic rainfall, and both the soils and leachates tested using bioassays. Soil bioassays were carried out using Eisenia fetida, whilst groundwater and leachates were tested using the Microtox test system and Daphnia magna 48 h acute tests. Analysis of the bioassay responses demonstrated that a number of the samples were toxic to test organisms, however, there were no significant statistical relationships between soil, groundwater and leachate toxicity. Nor were there significant correlations between soil, leachates and groundwater chemistry.

Animals↗
PubMed2001

Coupling of simulated moving bed chromatography and fractional crystallisation for efficient enantioseparation.

An optimised coupling of liquid chromatography and fractional crystallisation is suggested for efficient enantioseparation. As a first stage, a chromatographic separation, preferably simulated moving bed (SMB) chromatography, is applied to achieve an enantiomeric enrichment sufficient for a subsequent crystallisation. First results of the experimental and modelling work for the model system (+)-/(-)-mandelic acid in an aqueous solution are described. Chromatographic investigations involve the estimation of adsorption isotherms on a suitable chiral stationary phase and the simulation and optimisation of a corresponding SMB process. From the ternary phase diagram measured for the (+)-/(-)-enantiomer/ solvent system, the conditions required to crystallise a pure enantiomer from an asymmetric mixture can be derived. The productivity gains achievable from the combined process compared to the application of chromatography alone are discussed.

Chromatography, Liquid↗
PubMed2001

Ten-year review of hysterectomy morbidity and mortality: can we change direction?

The medical records of all women who underwent hysterectomy for benign disease performed between 1986 and 1995 were reviewed to ascertain the incidence of morbidity and mortality of abdominal, vaginal, and laparoscopically assisted vaginal hysterectomy at a university teaching hospital. A total of 1940 hysterectomies were performed during this period; 74% of hysterectomies were performed abdominally, 24% vaginally and 2% were laparoscopically assisted. In 80% of the patients uterine leiomyomas, adenomyosis, dysfunctional uterine bleeding or uterine prolapse were the indications for hysterectomy The overall complication rate was 44% for abdominal hysterectomy (AH) and 27.3% for vaginal hysterectomy (VH). An unintended major surgical procedure was required in 3% and 1% of women undergoing AH and VH respectively The rate of return to the operating room for haemostasis was 0.6% for AH and 0.2% for VH. The AH group was four times more likely than the VH group to require surgical intervention (36% versus 9%) at readmission. Vaginal hysterectomy was associated with a lower febrile morbidity and minor complication rate. Prophylactic antibiotics reduced the febrile morbidity for VH and AH by 50% (Student's t-test, p = 0.02) and 40% (Student's t-test, p < 0.001) respectively The overall mortality rate was 1.5 per 1000.

Aged↗
PubMed1999

Molecular analysis of Pseudomonas aeruginosa: epidemiological investigation of mastitis outbreaks in Irish dairy herds.

Pseudomonas aeruginosa is a pathogen in both humans and animals. This bacterium, most often associated with respiratory infections in cystic fibrosis patients, was found to be the causative agent in bovine mastitis outbreaks among 11 Irish dairy herds. Epidemiological findings suggested that the infection was spread to all herds by teat wipes that had been contaminated with this organism. Two molecular-typing strategies were used in an attempt to determine the genomic relationship(s), if any, of the P. aeruginosa strains isolated from the various herds and to verify whether the same strain was responsible for each outbreak. Thirty-six isolates from the mastitis outbreaks were tested and compared to fourteen clinical isolates from Cork University Hospital. With one exception, all outbreak-linked strains produced identical patterns when ribotyped with ClaI and PvuII enzymes. Eight of the clinical isolates gave the same ClaI ribotype pattern as the mastitis-causing strains. However, PvuII proved more discriminatory, with only the outbreak isolates producing identical patterns. Similar results were obtained with RW3A-primed DNA amplification fingerprinting, with all outbreak isolates except one displaying the same fingerprint array. The clinical strains produced several fingerprint patterns, all of which were different from those of the mastitis-causing isolates. Fine-resolution DNA fingerprinting with a fluorescence-labelled RW3A primer also identified a number of low-molecular-weight polymorphisms that would have remained undetected by conventional methods. These data support the view that the same P. aeruginosa strain was responsible for the mastitis outbreaks in all 11 herds.

Animals↗
PubMed1998

Modeling of the primary and secondary drying stages of the freeze drying of pharmaceutical products in vials: numerical results obtained from the solution of a dynamic and spatially multi-dimensional lyophilization model for different operational policies.

A rigorous unsteady state and spatially multidimensional model is presented and solved to describe the dynamic behavior of the primary and secondary drying stages of the lyophilization of a pharmaceutical product in vials for different operational policies. The results in this work strongly motivate the aggressive control of freeze drying and it is found that heat input control that runs the process close to the melting and scorch temperature constraints yields (i) faster drying times, and (ii) more uniform distributions of temperature and concentration of bound water at the end of the secondary drying stage.

Freeze Drying↗
PubMed1997

Studies on the mass action effect of glucose in NIDDM and IDDM: evidence for glucose resistance.

UNLABELLED: The ability of hyperglycaemia to enhance glucose uptake was evaluated in 9 non-insulin-dependent (NIDDM), 7 insulin-dependent (IDDM) diabetic subjects, and in 6 young and 9 older normal volunteers. Following overnight insulin-induced euglycaemia, a sequential three-step hyperglycaemic clamp (+ 2.8 + 5.6, and + 11.2 mmol/l above baseline) was performed with somatostatin plus replacing doses of basal insulin and glucagon, 3-3H-glucose infusion and indirect calorimetry. In the control subjects as a whole, glucose disposal increased at each hyperglycaemic step (13.1 +/- 0.6, 15.7 +/- 0.7, and 26.3 +/- 1.1 mumol/kg.min). In NIDDM (10.5 +/- 0.2, 12.1 +/- 1.0, and 17.5 +/- 1.1 mumol/kg.min), and IDDM (11.2 +/- 0.8, 12.9 +/- 1.0, and 15.6 +/- 1.1 mumol/kg.min) glucose disposal was lower during all three steps (p < 0.05-0.005). Hepatic glucose production declined proportionally to plasma glucose concentration to a similar extent in all four groups of patients. In control subjects, hyperglycaemia stimulated glucose oxidation (+4.4 +/- 0.7 mumol/kg.min) only at +11.2 mmol/l (p < 0.05), while non-oxidative glucose metabolism increased at each hyperglycaemic step (+3.1 +/- 0.7; +3.5 +/- 0.9, and +10.8 +/- 1.7 mumol/kg.min; all p < 0.05). In diabetic patients, no increment in glucose oxidation was elicited even at the highest hyperglycaemic plateau (IDDM = +0.5 +/- 1.5; NIDDM = +0.2 +/- 0.6 mumol/kg.min) and non-oxidative glucose metabolism was hampered (IDDM = +1.8 +/- 1.5, +3.1 +/- 1.7, and +4.3 +/- 1.8; NIDDM = +0.7 +/- 0.6, 2.1 +/- 0.9, and +7.0 +/- 0.8 mumol/kg.min; p < 0.05-0.005). Blood lactate concentration increased and plasma non-esterified fatty acid (NEFA) fell in control (p < 0.05) but not in diabetic subjects. The increments in blood lactate were correlated with the increase in non-oxidative glucose disposal and with the decrease in plasma NEFA. IN CONCLUSION: 1) the ability of hyperglycaemia to promote glucose disposal is impaired in NIDDM and IDDM; 2) stimulation of glucose oxidation and non-oxidative glucose metabolism accounts for glucose disposal; 3) both pathways of glucose metabolism are impaired in diabetic patients; 4) impaired ability of hyperglycaemia to suppress plasma NEFA is present in these patients. These results suggest that glucose resistance, that is the ability of glucose itself to promote glucose utilization, is impaired in both IDDM and NIDDM patients.

Adult↗
PubMed1996

High-grade endometrial carcinoma in secretory endometrium in young women: a report of five cases.

Five cases of high-grade carcinoma occurring adjacent to secretory endometrium are described. One of the patients had the Lynch II syndrome, the others appeared to be sporadic. None of these cases appeared to be related to hyperestrogen. The presenting symptom in four was abnormal vaginal bleeding, and the other case was found incidentally in the course of investigations for infertility. There were delays in diagnosis due to the patients not seeking medical attention for abnormal bleeding, a reluctance of clinicians to perform dilatation and curettage, and difficulty in pathologic interpretation of the curettings. The interpretive problems related to extremely small volumes of tumor, difficulty in distinguishing carcinoma from menstrual endometrium, and difficulty in determining whether a carcinoma was endometrial rather or endocervical in origin. The tumors were aggressive, manifest by their high grade and stage. The importance of these cases is to impress upon clinicians and pathologists that endometrial carcinoma may occur in young women without any of the usual risk factors.

Adult↗
PubMed1994

Effect of sustained physiologic hyperinsulinaemia and hyperglycaemia on insulin secretion and insulin sensitivity in man.

Two study protocols to examine the effects of chronic (72-96 h) physiologic euglycaemic hyperinsulinaemia (+ 72 pmol/l) and chronic hyperglycaemic (+ 1.4 mmol/l) hyperinsulinaemia (+ 78 pmol/l) on insulin sensitivity and insulin secretion were performed in 15 healthy young subjects. Subjects received a three-step euglycaemic insulin (insulin infusion rates = 1.5, 3, and 6 nmol.kg-1.min-1) clamp and a hyperglycaemia (6.9 mmol/l) clamp before and after chronic insulin or glucose infusion. Following 4 days of sustained euglycaemic hyperinsulinaemia whole body glucose disposal decreased by 20-40%. During each insulin clamp step, the defect in insulin action was accounted for by impaired non-oxidative glucose disposal (p < 0.01). Chronic euglycaemic hyperinsulinaemia did not alter insulin-mediated suppression of hepatic glucose production. Following insulin infusion the ability of hyperglycaemia to stimulate insulin secretion was significantly diminished. Following 72 h of chronic glucose infusion (combined hyperglycaemic hyperinsulinaemia), there was no change in whole body glucose disposal. However, glucose oxidation during each insulin clamp step was significantly increased and there was a reciprocal decline in non-oxidative glucose disposal by 25-39% (p < 0.01); suppression of hepatic glucose production by insulin was unaltered by chronic hyperglycaemic hyperinsulinaemia. Chronic glucose infusion increased the plasma insulin response to acute hyperglycaemia more than twofold. These results demonstrate that chronic, physiologic hyperinsulinaemia, whether created by exogenous insulin infusion or by stimulation of endogenous insulin secretion, leads to the development of insulin resistance, which is characterized by a specific defect in the non-oxidative (glycogen synthetic) pathway. These findings indicate that hyperinsulinaemia should be considered, not only as a compensatory response to insulin resistance, but also as a self-perpetuating cause of the defect in insulin action.

Adult↗
PubMed1994

A nursing rehabilitation program for women with breast cancer receiving adjuvant chemotherapy.

PURPOSE/OBJECTIVES: To examine the effects of a comprehensive rehabilitation program on facilitating physical and psychosocial adaptation of women with breast cancer who are receiving adjuvant chemotherapy. DESIGN: Experimental. SETTING: Breast evaluation clinics of two New England medical centers with comprehensive cancer treatment programs. SAMPLE: 14 women (mean age = 44 years) receiving adjuvant chemotherapy for breast cancer (86% stage II) following surgical treatment. METHODS: Subjects were assigned randomly to the experimental group or the usual care group. Experimental group members began a structured exercise program of walking and attended support group meetings. All subjects were tested before beginning chemotherapy, during the course of chemotherapy, and one month following chemotherapy completion. MAIN RESEARCH VARIABLES: Performance status, physical functioning, psychosocial adjustment, self-concept and body image, and 12 symptoms (e.g., fatigue, nausea, anxiety). FINDINGS: Measures of physical performance, psychosocial adjustment, and symptom intensity revealed improved adaptation in subjects who completed the walking/support group program. CONCLUSIONS: Physical and psychosocial benefits from a modest walking exercise program and a support group are possible for patients receiving adjuvant chemotherapy. IMPLICATIONS FOR NURSING PRACTICE: Although more detailed research is necessary to answer some of the questions raised by this study, implementing the walking program and forming a support group are achievable in an outpatient setting.

Activities of Daily Living↗
PubMed1994

Making love: Australian adults' rating of its importance as a romantic act in a relationship.

A personal opinion survey was administered to 1207 adults assessing attitudes towards 13 romantic acts with regard to age and gender. The present study focused upon attitudes towards the perceived importance of making love as a romantic act in a relationship. The sample was divided into three age groups, 18 to 25 years, 26 to 35 years, and 36 to 45 years. Analysis showed that 600 men's mean rating on a 5-point scale for importance was higher than the 607 women's rating; however, no significant difference was found among age groups and the interaction of age and gender was nonsignificant.

Adolescent↗
PubMed1992

Field evaluation of a sampling and analytical method for environmental levels of airborne hexavalent chromium.

Hexavalent chromium, Cr(VI), has been classified as a human respiratory carcinogen. Airborne Cr(VI) emissions are associated with a number of industrial sources including metal plating, tanning, chromite ore processing, and spray painting operations; combustion sources such as automobiles and incinerators; and fugitive dusts from contaminated soil. There has been considerable interest within industry and the regulatory community to assess the potential cancer risks of workers exposed to Cr(VI) at levels substantially below the threshold limit value (TLV) of 50 micrograms/m3. To date, only the workplace sampling and analytical method (National Institute for Occupational Safety and Health [NIOSH] Method 7600) has been validated for measuring airborne Cr(VI), and it can accurately measure concentrations only as low as 500 ng/m3. This paper describes the field evaluation of a sampling and analytical method for the quantitation of airborne Cr(VI) at concentrations 5000 times lower than the current standard method (as low as 0.1 ng/m3). The collection method uses three 500-mL Greenberg-Smith impingers in series, operated at 15 Lpm for 24 hr. All three impingers are filled with 200 mL of a slightly alkaline (pH approximately 8) sodium bicarbonate buffer solution. The results of validation tests showed that both Cr(VI) and trivalent chromium, Cr(III), were stable in the collection medium and that samples may be stored for up to 100 days without appreciable loss of Cr(VI). Method precision based on the pooled coefficient of variation for replicate samples was 10.4%, and method accuracy based on the mean percent recovery of spiked samples was 94%. Both the precision and accuracy of the impinger method were within NIOSH criteria. This method could be used to measure ambient concentrations of Cr(VI) in the workplace caused by fugitive emissions from manufacturing processes or chromium-contaminated soils at workplace concentrations well below the current TLV (50 micrograms/m3) or permissible exposure limit (100 micrograms/m3).

Air Pollutants, Occupational↗
PubMed1991

Pancreatic pathology in pentamidine-induced diabetes in acquired immunodeficiency syndrome patients.

An acquired immunodeficiency syndrome patient who was treated with pentamidine for a pneumocystis infection developed hypoglycemia followed by diabetes mellitus. The pathologic findings in the pancreas consisted of a significant decrease in the number of insulin-positive cells as measured by immunoperoxidase techniques when compared with comparable tissue from an age- and sex-matched control. There was also a decrease in the staining intensity of the insulin-positive cells, an absolute increase in the glucagon-positive cells, and no significant change in the number of somatostatin-positive cells. Routinely stained histologic sections showed morphologic changes in the islets with features different from those described in insulin-dependent diabetes mellitus or those caused by the toxin Vacor. The islets had increased vascular spaces, no islet cell necrosis, no fibrosis, and no lymphocytic infiltrates when compared with an age-matched control.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Chronic radiation enteritis: a community hospital experience.

A retrospective study was undertaken to evaluate the operative management of patients with chronic radiation enteropathy. Thirty-eight affected patients from 1974 to 1986 were reviewed. Patients with recurrent cancer responsible for symptoms were excluded. Seventy-one percent of patients presented with bowel obstruction. Twenty-one patients were treated with bowel resection, while 17 were treated with a bypass procedure or diverting ostomy alone. Overall morbidity was 45%, and postoperative mortality was 16%. Patients in the bypass group were significantly older than those in the resection group (70.3 vs. 55.5 years, P = .024), suggesting that age may have been a determinant of the procedure performed. In our study there was no difference in outcome based on preexisting vascular disease, tumor site, type of procedure performed, or radiation dose. We conclude that resection is the procedure of choice in cases of chronic radiation enteritis requiring surgery except in cases with dense adhesions when enteroenterostomal bypass is a viable alternative.

Enteritis↗