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Biomedical subjects

K Cox

Publications and source records attributed to K Cox.

At least 163 records · Page 9Linked to original sources
PubMed1982

A sensitive radioimmunoassay for 11-deoxy-13, 14-dihydro-15-keto-11, 16-cyclo-prostaglandin E2: application as an index of prostaglandin E2 biosynthesis during human pregnancy and parturition.

A radioimmunoassay for 11-deoxy-13, 14-dihydro-15-keto-11, 16-cycloprostaglandin E2 (PGEM-II) is described. At pH 10.5, in the presence of albumin, 13, 14-dihydro-15-keto-prostaglandin E2 (PGEM-I) is transformed quantitatively into PGEM-II. Hence, after plasma samples are subjected to this transformation procedure, PGEM-II can be measured in such samples and be a true reflection of PGEM-I production and thereby prostaglandin E2 (PGE2) biosynthesis. The antiserum raised against PGEM-II is minimally cross-reactive with all prostaglandins tested (less than 0.01%). The mean least detectable mass of PGEM-II is 0.8 pg and the mean mass of added PGEM-II required to displace zero-point binding by 50% is 16.6 pg. The assay meets all the standard criteria for accuracy, reproducibility and parallelism. Concentrations of PGEM-II measured by this assay in peripheral plasma from men and nonpregnant women are similar to those reported for PGEM-I after measurements by gas chromatography - mass spectrometry. Plasma concentrations of PGEM-II in men were greater than in nonpregnant women. PGEM-II in increased concentration was found in early pregnancy although concentrations declined in the third trimester until labor when a significant increase was found. Concentrations of PGEM-II in umbilical venous plasma were significantly greater than those in maternal plasma.

Adult↗
PubMed1981

Rhomboid flap dynamics.

The rhomboid flap is a reliable, versatile, and widely used tool in head and neck surgery. Although its geometry is well described, the mechanics of the flap have not been scientifically investigated. For example, there is disagreement whether the maximum tension is located at the closure of the donor site or at the tip of the flap. An experimental model using piglets and stabilized force gauges has been developed to measure the distribution of tension in a standard Limberg flap (60 degrees rhomboid). Variables evaluated include the size of the rhomboid, the amount of undermining, and the position of the flap on the animal. Consistent measurements show tension at the closure of the donor site to represent the majority of tension around the flap (58% average); the size of the rhomboid and degree of undermining do not change relative tensions. A composite figure discloses the relationship of the initially outlined flap to the final result and quantifies the observable changes in the length of sides.

Animals↗
PubMed1981

In search of criteria for the assessment of medical education.

This paper describes results of a study to assess whether an undergraduate educational curriculum is 'relevant'. The people surveyed comprised 290 individuals involved in medical education or health service administration. They were asked to suggest five major criteria for judging whether a medical undergraduate programme is relevant or not and to say whether they felt current curricula meet these criteria. Of those sampled, 40% replied. An analysis of the data from respondents showed that medical school professors and senior administrators of health services in Australia have roughly similar expectations of the outcome of medical education. Both groups were concerned that graduates be conscious of health care requirements and costs, that they have adequate clinical skills, knowledge in medical school subjects and skill in interacting with patients and managing their continuing education. On the various dimensions examined there were frequently strong expressions of dissatisfaction with current achievements.

Achievement↗
PubMed1980

Creating critical consciousness in health: applications of Freire's philosophy and methods to the health care setting.

Paulo Freire's philosophy of "education for critical consciousness" takes on special relevance within the context of the health care system. This dialogical approach to change, stressing action based on critical reflection by the people is seen here as importantly supplementing current efforts to deal with the "health care crisis" in the United States and many developing countries. Applications of the Freir approach in a health context of necessity involve the perception of health and medical care within the total oppressive structure of society. Viewed thusly, health "reform" cannot justifiably be envisioned except within the context of broader structural transformations. Two case studies are presented to illustrate the application of the Freire approach within a health context. Successful utilization of the methodology among peasants in rural Honduras and a relatively unsuccessful application among impoverished elderly residents of an urban United States ghetto are described and analyzed. Modifications of the approach to increase its usefulness in a variety of situational contexts are suggested. The potentials and limitations of this approach to radical change in the health field finally are described, along with lessons learned from initial work in the applications of conscientización to the health field.

California↗
PubMed1979

Upper gastrointestinal bleeding in children and adolescents.

This is a retrospective study of upper gastrointestinal hemorrhage in 68 children and adolescents who were less than 19 years old. In descending order of frequency, the five most common causes were duodenal ulcers, gastric ulcers, esophagitis, gastritis, and esophageal varices. There was male predominance in all diagnoses except gastric ulcers and gastritis. Signs and symptoms correlated poorly with the source of bleeding. Endoscopy was the most reliable method of identifying the bleeding site. Mortality correlated with the following: (1) initial hematocrit or hemoglobin level of less than 20% or less than 7 gm/100 ml, respectively, (2) transfusion requirements of greater than 85 ml/kg of blood without surgical intervention, (3) failure to identify the source of bleeding, (4) presence of a coagulation disorder, and (5) coexistence of another life-threatening disease.

Adolescent↗
PubMed1978

The appointment book.

Explore the source record for details and available documents.

Appointments and Schedules↗
PubMed1976

Oral prostaglandin E2 for labor induction in high-risk pregnancy.

Oral prostaglandin E2 (PGE2) was used alone or synergistically with intravenous oxytocin to induce labor in 84 women whose pregnancies were at high risk. A control group of 84 similar high-risk pregnancies where labor was induced with intravenous oxytocin alone was studied to compare the safety and efficacy of the two regimens. Oral PGE2 administration, combined with the synergistic effect of intravenous oxytocin, is safe for induction of labor in gravid women whose fetuses are at risk. Uterine polysystole, which is potentially dangerous, especially to the high-risk fetus, was not commonly encountered and only once was associated with transient fetal bradycardia. Uterine hypertonus was not encountered with PGE2; however, it did occur with oxytocin stimulation. Nausea and vomiting occurred in one third of the women treated with PGE2 but were well tolerated and required discontinuation of the drug in only one instance. There was no apparent advantage of using the combination PGE2 regimen in patients whose cervices were more favorable for induction of labor (Bishop score, 5 to 9). However, oral PGE2, used either alone or synergistically with oxytocin, appears twice as effective in inducing labor than was oxytocin alone in women in whom labor was considered to be "difficult to induce" (Bishop score, 0 to 4).

Administration, Oral↗
PubMed1975

Learning by experience. A student residential workshop in hospital.

A four-day residential workshop was conducted for students beginning their clinical studies at the St George Hospital in 1974. The aim of the workshop was that the students should understand the functioning of the hospital and feel comfortable as students in the hospital, so that they would learn their clinical skills more effectively in their subsequent years at the hospital. Each student lived in a hospital bed with an "illness" for two days, and spent another two days helping care for these "student patients" and exploring the hospital. Evaluation at the end of the workshop suggested that the objectives had been achieved.

Attitude of Health Personnel↗
PubMed1975

Further observations on the nature of pressor responsivity to angiotensin II in human pregnancy.

The pressor dose of infused angiotensin II was determined before and after rapid volume expansion with 800 to 1075 ml of high-hematocrit blood. There was no remarkable change in sensitivity to infused angiotensin demonstrated except in two instances in which transient volume overload developed. The data support the hypothesis that increased angiotensin sensitivity observed in patients with pregnancy-induced hypertension is the consequence of increased vascular responsivity.

Anemia, Sickle Cell↗
PubMed1973

Sites of formation of the serum proteins transferrin and hemopexin.

Sites of synthesis of hemopexin and transferrin were determined by culturing various tissues of rabbits and monkeys in the presence of labeled amino acids. Labeling of the serum proteins was examined by means of autoradiographs of immunoelectrophoretic patterns as well as by precipitation in the test tubes employing immunospecific antisera. Good correlation was seen between the results obtained by the two different methods. The liver was found to be the only site of many tissues studied that synthesized hemopexin. Transferrin production was observed in the liver, submaxillary gland, lactating mammary gland, testis, and ovary.

Amino Acids↗
PubMedDate not supplied

Enhancing cancer clinical trial management: recommendations from a qualitative study of trial participants' experiences.

Using a qualitative approach, a total of 55 adult patients with advanced cancer were interviewed to examine their perceptions of participating in early phase anti-cancer drug trials. Patients' views and experiences were explored, primarily through the use of in-depth interviews, with additional information accessed through two widely-used quality of life questionnaires, at the beginning of, during and after trial participation. The picture of trial participation established from this work suggests that it is a dynamic process, that has a different meaning and impact according to the stage of trial involvement the patient is experiencing. The findings identify how patients perceived the offer of the trial, dealt with the trial treatment, and came to terms with trial conclusion. The insight and understanding that this work provides in terms of the impact of trial involvement over time as well as details of patients' information, decision-making and support needs has significant implications for cancer clinical trial management. The recommendations put forward in this paper focus on acknowledging the contribution trial participants make to cancer research, enhancing the process of preparing patients for trial participation, recognizing the need for continuing care, the incorporation of patients and potential patients' views into the clinical trials system, and educating the public about clinical trials.

Adaptation, Psychological↗
PubMedDate not supplied

Human halothane metabolism, lipid peroxidation, and cytochromes P(450)2A6 and P(450)3A4.

OBJECTIVE: Halothane undergoes both oxidative and reductive metabolism by cytochrome P450 (CYP), respectively causing rare immune-mediated hepatic necrosis and common, mild subclinical hepatic toxicity. Halothane also causes lipid peroxidation in rodents in vitro and in vivo, but in vivo effects in humans are unknown. In vitro investigations have identified a role for human CYPs 2E1 and 2A6 in oxidation and CYPs 2A6 and 3A4 in reduction. The mechanism-based CYP2E1 inhibitor disulfiram diminished human halothane oxidation in vivo. This investigation tested the hypotheses that halothane causes lipid peroxidation in humans in vivo, and that CYP2A6 or CYP3A4 inhibition can diminish halothane metabolism. METHODS: Patients (n = 9 each group) received single doses of the mechanism-based inhibitors troleandomycin (CYP3A4), methoxsalen (CYP2A6) or nothing (controls) before a standard halothane anaesthetic. Reductive halothane metabolites chlorotrifluoroethane and chlorodifluoroethylene in exhaled breath, fluoride in urine, and oxidative metabolites trifluoroacetic acid and bromide in urine were measured for 48 h postoperatively. Lipid peroxidation was assessed by plasma F2-isoprostane concentrations. RESULTS: The halothane dose was similar in all groups. Methoxsalen decreased 0- to 8-h trifluoroacetic acid (23 +/- 20 micromol vs 116 +/- 78 micromol) and bromide (17 +/- 11 micromol vs 53 +/- 49 micromol) excretion (P < 0.05), but not thereafter. Plasma F2-isoprostanes in controls were increased from 8.5 +/- 4.5 pg/ml to 12.5 +/- 5.0 pg/ml postoperatively (P < 0.05). Neither methoxsalen nor troleandomycin diminished reductive halothane metabolite or F2-isoprostane concentrations. CONCLUSIONS: These results provide the first evidence for halothane-dependent lipid peroxidation in humans. Methoxsalen effects on halothane oxidation confirm in vitro results and suggest limited CYP2A6 participation in vivo. CYP2A6-mediated, like CYP2E1-mediated human halothane oxidation, can be inhibited in vivo by mechanism-based CYP inhibitors. In contrast, clinical halothane reduction and lipid peroxidation were not amenable to suppression by CYP inhibitors.

Adult↗
PubMedDate not supplied

Pediatric intestinal transplantation at Packard Children's Hospital/Stanford University Medical Center: report of a four-year experience.

We report a 4-year experience of a new program in pediatric intestinal transplantation. Among 50 children referred for evaluation, 27 were listed for transplantation. Two children originally listed for combined liver/small bowel transplant were changed to isolated intestinal transplant as rehabilitation efforts resulted in full recovery of hepatic function. Eighteen children received 18 grafts: 12 liver/intestine, 5 isolated intestine, and 1 multivisceral. Mean age at transplant was 3.6 year with 75% of patients aged 0 to 2 years. Five listed children died while waiting and four were still on the list. Immunotherapy included antithymocyte globulin induction and tacrolimus, sirolimus, and prednisone maintenance. At 1 year, patient and graft survivals were 75% and 67%, respectively. For isolated intestine, 1 year survivals were 100% and 75%, while for combined liver/intestine, they were 71% for both. Enteral autonomy is 100% with total parenteral nutrition stopping by 35.8 days (mean). We had two patients develop posttransplant lymphoproliferative disorder and three, exfoliative rejection, one of whom recovered completely. In conclusion, our program in pediatric intestinal transplantation has become well established with a high proportion of smaller/younger children receiving grafts. Outcomes achieved levels expected based on The Intestinal Transplant Registry and UNOS criteria, which were better than expected for isolated intestinal transplants and achievement of enteral autonomy.

ABO Blood-Group System↗
PubMedDate not supplied

Specificity of substance use in anxiety-disordered subjects.

The current research (1) examines empirical evidence to substantiate the relationship between substance choice and chronology of onset of anxiety and substance use disorders, and (2) provides information on the specificity of substance choice among anxiety disorders. A study group of 181 subjects in the Harvard Anxiety Research Project (HARP) who had a history of substance use disorder were the focus of this examination. Subjects whose anxiety disorder had an onset before their substance use disorder (primary anxiety) were compared with those whose substance use preceded onset of an anxiety disorder (secondary anxiety) for differences in distribution of subjects among categories of substance of abuse. Primary and secondary anxiety groups do not have different ages of onset for substance use disorder, nor was there greater likelihood for choosing alcohol for any of the anxiety disorders. However, there is a decreased risk of alcohol use in the small group of generalized anxiety subjects and an increased risk of opioid use in the small group of posttraumatic stress disorder subjects. There was no indirect support for the self-medication hypothesis. Neither age of onset data, specific substance association, nor proximal diagnosis association support a simple interaction. The strongest finding supported an "avoidance" of CNS stimulants.

Adult↗