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Biomedical subjects

D S Collier

Publications and source records attributed to D S Collier.

At least 19 recordsLinked to original sources
PubMed2001

Fat necrosis of the breast: a cytological and clinical study.

Fat necrosis of the breast is a sterile condition that usually results from trauma to the breast. It may present with a breast lump that, on clinical and mammographic examination, can mimic malignancy. The literature suggests that fat necrosis of the breast can only be diagnosed accurately by histological examinations of breast biopsies. In this paper, we review the findings of a series of 35 patients in whom fat necrosis was diagnosed on fine needle aspiration cytology. Repeated fine needle aspiration cytology with close follow-up have proven to be a reliable method of establishing the diagnosis of fat necrosis of the breast, thereby reducing the necessity for open biopsy.

Journal Article↗
PubMed2001

Omeprazole pharmacodynamics and gastric acid suppression in critically ill pediatric transplant patients.

OBJECTIVE: To characterize the pharmacodynamics and pharmacokinetics of omeprazole suspension in critically ill pediatric liver/intestinal transplant patients. DESIGN: Open-label pharmacodynamic and pharmacokinetic study. SETTING: Pediatric intensive care unit of an academic medical center. PATIENTS: Eleven pediatric liver and/or intestinal transplant patients. INTERVENTIONS: Extemporaneously prepared 0.5 mg/kg omeprazole suspension every 12 hrs via nasogastric tube before sequential measurements of omeprazole serum concentration and gastric pH monitoring. Gastric pH was monitored continuously for 48 hrs and plasma omeprazole concentrations were determined upon first and multiple dosing. MEASUREMENTS AND MAIN RESULTS: Mean onset of action of omeprazole in a sodium bicarbonate vehicle was 62 +/- 82 mins (range, 2-226 mins). Subjects <4 yrs of age exhibited a more variable onset of omeprazole action (range, 3-226 mins) when compared with older subjects (onset of action, 2-40 min). Omeprazole maximum concentration and area under the concentration-time curve for the dosage interval were significantly greater upon multiple dosing when compared with the first dose. Mean baseline gastric pH in this study population was 1.0 +/- 0.8. Gastric pH remained >4.0 for 78.8% +/- 18.9% of the first dosage interval and 97.8% +/- 5.4% of multiple dosage intervals regardless of age when administered twice daily as a suspension. CONCLUSION: These results support the use of omeprazole administered twice daily as a suspension to maintain gastric pH of >4.0 and to achieve maximal pharmacodynamic effect in pediatric liver and/or intestinal transplant patients.

Journal Article↗
PubMed2000

Extracorporeal liver perfusion using human and pig livers for acute liver failure.

BACKGROUND: Patients with fulminant hepatic failure (FHF) often die awaiting liver transplantation. Extracorporeal liver perfusion (ECLP) has been proposed as a method of "bridging" such patients to transplantation. We report the largest experience to date of ECLP using human and porcine livers in patients with acute liver failure. METHODS: Patients with FHF unlikely to survive without liver transplantation were identified. ECLP was performed with human or porcine livers. Patients underwent continuous perfusion until liver transplantation or withdrawal of support. Two perfusion circuits were used: direct perfusion of patient blood through the extracorporeal liver and indirect perfusion with a plasma filter between the patient and the liver. FINDINGS: Fourteen patients were treated with 16 livers in 18 perfusion circuits. Nine patients were successfully "bridged" to transplantation. ECLP stabilized intracranial pressure (ICP) and cerebral perfusion pressure (CPP). Arterial ammonia levels fell from a median of 146 to 83 micromol/liter within 12 hr and this reduction was maintained at least 48 hr. Pig and human ECLP lowered ammonia levels equally. Serum bilirubin levels also fell from a median of 385 to 198 micromol/liter over the first 12 hr but the response was not sustained as well with porcine livers. There was no immunological benefit to using the the filtered perfusion circuit. INTERPRETATION: These data demonstrate that ECLP is safe and can provide metabolic support for comatose patients with fulminant hepatic failure for up to 5 days. While labor and resource intensive, this technology is available to centers caring for patients with acute liver failure and deserves wider evaluation and application.

Adolescent↗
PubMed2000

Envelope mastectomy with immediate reconstruction (EMIR).

AIMS: To develop an oncologically safe and aesthetically acceptable technique for mastectomy, using a muscle flap and tissue expander through one incision. METHODS: Twelve consecutive patients (mean age 40) underwent an envelope mastectomy (skin and nipple sparing), with immediate reconstruction with a latissimus dorsi muscle flap and tissue expander. Assessment of cosmesis was by review of pre- and post-operative photographs by an independent observer. RESULTS: During follow-up there have been no recurrences. Assessment of cosmesis gave a score of 44 out of 48 (92%). One prosthesis was removed due to erosion of the prosthesis through the skin. CONCLUSIONS: In patients with large lesions, multi-focal lesions (both invasive and in situ) and recurrent phyllodes tumours may undergo an oncologically safe mastectomy with immediate reconstruction through a single incision that is inconspicuous being in the mid-axillary line. Although follow up is only 8.5 months, long-term studies are being undertaken.

Adult↗
PubMed2000

Circum-areolar mastectomy with immediate reconstruction (CAMIR).

AIMS: To develop an oncologically safe and aesthetically acceptable technique for mastectomy using a myocutaneous flap and tissue expander for patients with neoplastic involvement of the nipple. METHODS: Fourteen consecutive patients (mean age 40 years) underwent a circum-areolar mastectomy with immediate reconstruction using a latissimus dorsi myocutaneous flap and tissue expander. Assessment of cosmesis was by review of pre- and post-operative photographs by an independent observer. RESULTS: During a mean follow-up of 11.4 months there have been no local recurrences. There were two deaths: pulmonary embolus (one) and distant metastatic disease (one). Assessment of cosmesis gave a score of 47 out of 56 (84%). CONCLUSIONS: In patients with tumours involving the nipple, mastectomy with immediate reconstruction may be used to achieve a good cosmetic result. The replacement nipple is fashioned from a circle of skin attached to the latissimus dorsi myocutaneous harvest.

Adult↗
PubMed1999

Effect of omeprazole, lansoprazole, and ranitidine on the DNA synthesis of mononuclear cells.

OBJECTIVE: To examine and compare the effects of omeprazole, lansoprazole, and ranitidine on the DNA synthesis of peripheral blood mononuclear cells. DESIGN: Ex vivo laboratory study. SETTING: Clinical research laboratory of an academic medical center. SUBJECTS: Healthy volunteers. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Venous blood was collected from normal subjects and peripheral blood mononuclear cells (PBMCs) were isolated using centrifugation techniques over a Ficoll-Hypaque density gradient. PBMCs were added to 12-well culture plates in four groups of media: a) control; b) control plus lansoprazole (25 microg/mL); c) control plus omeprazole (0.35 microg/mL); and d) control plus ranitidine (50 microg/mL). PBMCs were exposed to the drug for 96 hrs, with addition of phytohemagglutinin (2.5 microg/ mL) for the last 48 hrs, and 3H-thymidine (1 microCi) during the final 6 hrs. PBMCs were filtered onto glass-fiber filter paper and the radioactivity was determined by scintillation counting. Since radioactivity is measured only in those cells undergoing DNA synthesis or cell division, results are expressed as quantification of 3H-thymidine uptake. Median disintegrations per min (DPM)/number of PBMCs per well+/-SEM are reported: control 68.3+/-37.8; ranitidine 38.4 +/-94.2; lansoprazole 14.6+/-84.4; and omeprazole 15.1+/-48.9. There was a significant difference between lansoprazole vs. ranitidine (p< .01), and omeprazole vs. ranitidine (p< .05), and no significant difference between lansoprazole and omeprazole. CONCLUSIONS: This is the first study to compare the potential immunomodulating effects of these commonly used agents. Ranitidine caused increased DNA synthesis in PBMCs when compared with lansoprazole and omeprazole. This phenomenon may be an important, often disregarded, effect of histamine-2-receptor antagonists when used in postsurgical or trauma patients who have T-lymphocyte-mediated immune suppression.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1998

Use of disodium pamidronate in children with hypercalcemia awaiting liver transplantation.

We report four children with advanced liver disease awaiting liver transplantation who developed moderately severe hypercalcemia (range: 1.65-2.40 mmol/L) while receiving total parenteral nutrition. Hypercalcemia had been unresponsive to cessation of calcium intake and therapy with loop diuretics and calcitonin. One or two intravenous doses of disodium pamidronate (35-50 mg/m2) resulted in normalization of plasma calcium concentration within 2-4 d in all four children. Pamidronate may be useful for children with hypercalcemia associated with liver disease.

Child↗
PubMed1995

Evaluation of the pharmacokinetic interaction between cimetidine or famotidine and cyclosporine in healthy men.

OBJECTIVE: To investigate the potential interaction between cimetidine or famotidine and cyclosporine in healthy men. DESIGN: All subjects received oral cyclosporine at baseline, after the first week of 1 histamine2 (H2)-blocker, and a third time after a 1-week washout plus 1 week of the second H2-blocker. Blood samples were collected just before each dose of cyclosporine and for up to 36 hours afterward for pharmacokinetic analysis. SETTING: A college of pharmacy in a university teaching hospital. PARTICIPANTS: The study population consisted of 8 healthy men at least 19 years of age. MAIN OUTCOME MEASURES: Cyclosporine concentrations in whole blood were measured using a polyclonal fluorescence polarization immunoassay. Cyclosporine pharmacokinetic parameters during each of the 3 treatment periods were compared. RESULTS: The average times to maximum cyclosporine concentrations were similar between baseline (3.2 h), cimetidine (2.9 h), and famotidine (3.6 h) dosing periods. There were no significant differences in area under the curve, half-life, or maximum concentration during the 3 dosing periods. CONCLUSIONS: Neither cimetidine or famotidine produced a significant change in the pharmacokinetics of single-dose oral cyclosporine in healthy men.

Adult↗