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Biomedical subjects

M O'Brien

Publications and source records attributed to M O'Brien.

At least 181 records · Page 10Linked to original sources
PubMed1994

Relationship of platelet aggregation to bleeding after cardiopulmonary bypass.

Excessive bleeding after cardiopulmonary bypass operations is a persistent problem. This study assessed the influence of platelet function on blood loss for 134 patients undergoing cardiopulmonary bypass. Platelet function was measured by platelet aggregation in platelet-rich plasma and whole blood using collagen as the agonist. Adenosine triphosphate release was assessed concurrently. Measurements were made 1 day before operation and 1 hour after the cessation of cardiopulmonary bypass. Three important findings were made. First, statistically significant correlations were shown between preoperative and postoperative platelet aggregation and blood drainage for the first 3 hours postoperatively. Second, correlations were greatest when preoperative measurement was performed on whole blood and postoperative measurement was performed on platelet-rich plasma. Third, patients with reduced postoperative platelet aggregation in platelet-rich plasma had significantly greater transfusion requirements in the first 24 hours postoperatively. In defining the 16 patients who bled excessively among the 134 patients studied, the preoperative aggregation in whole blood had a sensitivity of 62%, specificity of 75%, positive predictive value of 26%, and negative predictive value of 94%. The postoperative aggregation in platelet-rich plasma had a sensitivity of 86%, specificity of 69%, positive predictive value of 28%, and negative predictive value of 97%. These results indicate that preoperative and postoperative measurement of platelet aggregation may provide a rationale for the prophylaxis or treatment of patients to reduce blood loss after cardiopulmonary bypass.

Adenosine Triphosphate↗
PubMed1994

The use of cisplatin plus 5-fluorouracil chemotherapy in an unselected group of patients with recurrent squamous cell carcinoma of the head and neck.

Cisplatin and infusional 5-fluorouracil (5-FU) has become regarded as the standard chemotherapy for squamous cell carcinoma (SCC) of the head and neck. Results of phase II studies vary widely and do not always reflect the activity of regimen in general clinical practice. We have treated 20 consecutive patients with cisplatin 100 mg/m2 and 5-FU given as a 4-day infusion at 1 g/m2 for 24 h. In order to reflect more accurately the activity of this regimen in everyday practice we have followed as many patients as possible to relapse and death and measured the duration of remissions from the end of treatment. 6 patients responded (30%, 95% CI: 10-48%) with 1 patient achieving a complete remission. Partial remission lasted for 3-18 months and the complete remission lasted for 7 months. Median survival of patients from the date of first treatment was 7 months (range 1 week-20.5 months). The regimen was well tolerated but required hospitalisation. We conclude that this regimen is well tolerated, active and a good choice for treating recurrent SCC of the head and neck in an unselected population of patients with recurrent disease in the context of everyday oncological practice.

Adult↗
PubMed1994

Right gastroepiploic artery conduit use in myocardial revascularization.

The majority of surgeons use the saphenous vein or internal mammary artery as conduits in coronary artery bypass grafting (CABG). Improved long-term patient survival rates after CABG have increased the need for alternative conduits in reoperations for myocardial revascularization. In the past 20 years, surgeons have begun using the right gastroepiploic artery (GEA) as an alternative conduit in CABG. Perioperative nursing care of patients undergoing right GEA grafting for myocardial revascularization includes documentation of patient problems and nursing actions taken; preoperative patient assessment and teaching; intraoperative management of patient positioning, temperature, and skin integrity; and postoperative care to maintain the patient's hemodynamic stability and avoid complications.

Adult↗
PubMed1994

Nasopalatine duct cysts and the role of magnetic resonance imaging.

Nasopalatine duct cysts are a common etiology for anterior midline palatal masses, which may be seen by craniofacial surgeons. Plain radiographs, computed tomography, and magnetic resonance imaging (MRI) scans may be useful in their diagnoses. Clinically, they may be symptomatic in more than 70% of patients. Treatment is surgical excision, with a recurrence rate of approximately 10%. We present a case of a midline, palatal mass in a 13-year-old girl in whom an MRI scan was utilized and evaluated as a radiological tool in the diagnosis and treatment plan of a nasopalatine duct cyst. An MRI scan is useful diagnostic tool; it provides exceptional definition of the anatomy in this region. A critical review of the literature, as well as pathogenesis and treatment recommendations, are provided.

Adolescent↗
PubMed1994

Detection of dimeric inhibin throughout the human menstrual cycle by two-site enzyme immunoassay.

OBJECTIVE: We have developed and validated a two-site immunoassay for the measurement of dimeric inhibin in plasma and subsequently measured dimeric inhibin levels in plasma through the normal female menstrual cycle. DESIGN: Recombinant inhibin added to plasma samples was quantitatively recovered in both follicular and luteal phase, and serial dilutions of samples were tested for parallelism to similar dilutions of recombinant 32 kDa inhibin. Daily samples were assayed from four women through a menstrual cycle. PATIENTS: (a) Four groups of six women who (i) were in the follicular phase of a normal menstrual cycle, (ii) were in the luteal phase of a normal menstrual cycle, (iii) were post-menopausal and (iV) who had received hMG to induce superovulation. (b) Four healthy female volunteers aged 25-33. RESULTS: Post-menopausal women had less than 2 ng/l of inhibin whereas six women treated with hMG had dimeric inhibin concentrations up to 1125 ng/l. During the early follicular phase, at the time of onset of menstruation, extremely low levels of dimeric inhibin were found (3.4 ng/l (CI 2.2-5.0)) while in the late follicular phase, there was a marked increase in dimeric inhibin concentration. The concentration of dimeric inhibin was maximal (65.6 ng/l (CI 53.1-81.1)) in the mid-luteal phase. The overall pattern of dimeric inhibin concentration during the menstrual cycle was similar to that observed with previous inhibin assays although the magnitude of change was considerably greater. CONCLUSION: The human ovary, in particular the corpus luteum, secretes significant amounts of dimeric and therefore biologically active inhibin.

Adult↗
PubMed1994

Trends in motor vehicle and firearm deaths in Wisconsin: an analysis for examining prevention strategies.

Motor vehicle crash (MVC) deaths in Wisconsin have steadily declined since the 1970s. Multiple prevention strategies have been applied resulting in the lowest MVC death rate in 30 years. If current trends continue, firearms will exceed MVCs in Wisconsin by the year 2001. Multiple prevention strategies based on the public health model need to be applied to firearms.

Accidents, Traffic↗
PubMed1994

Reliability and diagnostic efficacy of parents' reports regarding children's exposure to marital aggression.

Mothers, fathers, and 8- to 11-year-old children from 181 two-parent families independently reported on the occurrence of husband-to-wife physical aggression and wife-to-husband physical aggression; parents additionally indicated whether the child had been witness to the aggression. First this study examined interspousal agreement regarding whether parents have been physically aggressive toward one another and whether the child has witnessed interparental physical aggression. There was moderate agreement between parents as to the occurrence of physical aggression and only fair agreement as to whether the child saw or heard the aggression. Second, this study explored the diagnosticity of a joint parent report as an indicator of child exposure to marital aggression. Receiver operating characteristic (ROC) curves are presented separately for husbands' and wives' aggression, indicating the explicit trade-off between true positives (sensitivity) and false positives (one minus specificity) in using the joint parent report as a diagnostic indicator. Standard ROC analysis suggests that the joint parent report is equally diagnostic in predicting children's reports of exposure to husbands' and wives' aggression. Finally, decisions regarding how to use parent reports as an indicator of children's exposure to marital aggression are discussed as depending on the base rate of child reports of exposure and the objective sought in classifying children and/or families.

Adult↗
PubMed1994

The "Buy-Max" mouthguard: oral, peri-oral and cerebral protection for contact sports.

Protective equipment plays an important role in the reduction of certain sports injuries. Mouthguards have been shown to reduce the number of orafacial and cerebral injuries in a variety of contact sports including rugby, hockey and boxing. The varieties of mouthguards available are discussed. The most effective, but also the most expensive, is the "Bimaxillary" mouthguard popularised by Chapman. It covers both dental arches and as the jaws are held in the position of heavy breathing, air flow is not impeded. The advantages and disadvantages of the various types of mouthguard are discussed.

Adolescent↗
PubMed1993

Immunoassays for inhibin and its subunits. Further applications of the synthetic peptide approach.

We describe the preparation of a new rat monoclonal antibody (CRC1) to the N-terminal sequence of the 43 kDa subunit of human ovarian inhibin, and its use together with other anti-peptide monoclonal antibodies, in two-site immunoassays for the detection of inhibin-related material in biological fluids. The Fab fraction of a mouse monoclonal antibody (R1) to the N-terminal portion of the 20 kDa alpha subunit, coupled to alkaline phosphatase, was used for detection, and either CRC1 or a monoclonal antibody (E4) to the beta-A subunit were used as capture antibodies. The E4/R1 combination, expected to measure dimeric bioactive inhibin, could detect less than 2 pg/ml of recombinant inhibin in diluent, gave good recovery of activity spiked into human blood, and could measure significant levels of immunoreactivity in sera from women undergoing ovulation induction, and in some normal women. Sera from post-menopausal women contained undetectable levels. Apparent inhibin levels in human follicular fluid were increased six-fold by pretreatment with 8 M urea, suggesting masking of epitopes in this fluid. Activin cross-reactivity in the assay was 0.05%. The R1/CRC1 assay, expected to measure only large molecular weight forms of inhibin or its alpha subunit, could detect immunoreactivity in human FF diluted 50,000-fold, and in all sera tested, although the levels in the hyperovulated women were higher. By contrast to the E4/R1 assay much of the immunoreactivity was labile during the clotting process, or subsequent assay, and reliable measurements on blood with this assay will require special sample collection procedures. These results demonstrate the value of anti-peptide monoclonal antibodies in the study of inhibin, and the results obtained with CRC1 show that antibodies useful for immunoassays can sometimes be obtained without the purified target molecule being available for immunization or screening.

Amino Acid Sequence↗
PubMed1993

Response to neoadjuvant chemotherapy in children with pineoblastoma.

BACKGROUND: The outlook of children with pineoblastoma treated with radiation therapy alone is extremely poor, but neoadjuvant chemotherapy has been tried only in a few cases of this rare childhood brain tumor with poor prognosis. METHODS: Three consecutive children 3 to 7 years of age received neoadjuvant chemotherapy consisting of etoposide 100 mg/m2 days 1 to 3, cisplatin 100 mg/m2 day 1, and vincristine 1.5 mg/m2 day 1, repeated every 4 weeks. After four courses of chemotherapy, patients underwent craniospinal irradiation. The radiation doses to the primary site ranged from 5040 to 5440 cGy and craniospinal axis radiation dose was 2520 to 3060 cGy. RESULTS: After chemotherapy, mild myelosuppression occurred in all three and mild to moderate bilateral high-frequency sensorineural hearing loss occurred in two of the three patients. One patient remains in near complete resolution of the tumor at 2 years after diagnosis and another remains in CR for 5 years. One patient achieved PR for 5 months but eventually died of progressive tumor. CONCLUSIONS: This study suggests that the neoadjuvant chemotherapy as used here is effective and has acceptable toxicity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Childhood intracranial meningiomas after high-dose irradiation.

BACKGROUND: Irradiation, either alone or in association with other factors, is thought to play a role in the causation of intracranial meningioma. METHODS: The authors report two 15-year-old patients with convexity meningiomas as a result of high-dose irradiation received at a young age and review the English language literature reports of 13 pediatric patients with meningiomas after high-dose irradiation. The clinical characteristics of the 15 patients are presented. RESULTS: There were nine girls and six boys. The mean age at the time of irradiation was 2.5 years (2 months-9 years), and the mean age at diagnosis of meningioma was 13 years (5-15.5 years). The mean radiation dose was 4154 cGy (1500-8000 cGy). In 11 of the 15 patients, the meningioma was located in the calvarial area. Only 1 of 15 had multiple tumors, and only two of the tumors were clearly malignant at diagnosis. In ten patients, gross total resection was recorded, and two patients underwent subtotal resection. Three died of recurrent/disseminated meningiomas. CONCLUSIONS: This study suggests that meningiomas after high-dose radiation in children are mostly calvarial in location, rarely multiple, mostly benign in histologic type, and that complete removal is possible in most patients. The age at the time of radiation is young (mean age, 2.5 years) and the latent period is short (mean, 10.8 years). Although the clinical course of radiation-induced meningiomas in childhood generally is benign, high doses of radiation at a young age are to be avoided, and other means of therapy should be used if possible.

Astrocytoma↗
PubMed1993

Squamous metaplasia of extrahepatic biliary system in an AIDS patient with cryptosporidia and cholangitis.

AIDS-related cholangiopathy is an increasingly recognized syndrome associated with significant morbidity and mortality. The mechanism of cholangiopathy is unknown but is assumed to be related to infectious pathogens such as CMV and cryptosporidia. The case of a Haitian with HIV and long-standing intestinal cryptosporidiosis who presented with cholangitis and protuberant intrabiliary filling defects is reported. Histopathological examination of biliary biopsies revealed previously unreported extensive squamous metaplasia of the bile duct epithelium, and the histogenesis of this condition is discussed. Chronic cryptosporidial infestation may be directly pathogenic resulting in squamous metaplasia that mimics biliary malignancy.

AIDS-Related Opportunistic Infections↗
PubMed1993

Bilateral quadriceps tendon rupture--a case report.

The diagnosis of rupture of the quadriceps tendon is made relatively infrequently and bilateral simultaneous rupture is a rarity. We report a case of spontaneous bilateral rupture of the quadriceps tendon in a patient with documented chronic renal insufficiency and secondary hyperparathyroidism. A predisposing cause to the condition as obtained in this case, has been described in cases previously published in the literature.

Humans↗
PubMed1993

Pleural drainage systems.

The physics and the physiological principles of pleural or chest drainage systems are reviewed. The clinical management and complications of pleural drainage are summarised.

Drainage↗