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Biomedical subjects

D J Murphy

Publications and source records attributed to D J Murphy.

At least 217 records · Page 12Linked to original sources
PubMed1979

Light-dependent Induction of Polyunsaturated Fatty Acid Biosynthesis in Greening Cucumber Cotyledons.

Greening cucumber (Cucumis sativus L.) cotyledons exhibited dramatic increases in the ability to desaturate exogenously added [1-(14)C]oleic acid and [1-(14)C]linoleic acid within 2 to 3 hours of illumination. These increases were effectively inhibited by 10 micrograms per milliliter cycloheximide. Oleate desaturation remained at a high level in constant light for 5 to 6 days after induction and then declined by about 50%; when returned to the dark, the tissue showed a sharp decrease in conversion of [(14)C]oleate to [(14)C]linoleate. Linoleate desaturation reached a maximum about 15 hours after induction and declined immediately thereafter while the tissue still was in the light; after induction had peaked return of the tissue to the dark showed a dramatic fall of linoleate desaturation. The changes in desaturation were correlated with the conversion of the principal fatty acid in the etiolated cotyledons, linoleate, to alpha-linolenate, and with the assembly of the chlorophyll-containing photosynthetic membranes. The incorporation of [1-(14)C]acetate into lipids showed no significant light stimulation. The role of light in the regulation of certain aspects of plant metabolism during development is discussed.

Journal Article↗
PubMed1979

Elongation Pathway for alpha-Linolenic Acid Synthesis in Spinach Leaves: A Reexamination.

Leaf slices from spinach exhibited considerable variation in their incorporation of [(14)C]bicarbonate and [1-(14)C]acetate into fatty acids. Reductive ozonolysis studies indicated that all the (14)C-labeled fatty acids were synthesized de novo; no in vivo evidence was found for the previously proposed elongation of hexadecatrienoate to alpha-linolenate.

Journal Article↗
PubMed1974

Schistosomiasis mansoni in Yemeni in California: duration of infection, presence of disease, therapeutic management.

Investigations of schistosomiasis mansoni in 218 Yemeni agricultural workers in the San Joaquin Valley of California revealed a prevalence of 56%. In those infected, quantitative egg counts performed by the Kato thick smear method revealed that 57% had light infections (1-100 eggs/g), 27% moderate infections (101-400 eggs/g), and 16% heavy infections (greater than 400 eggs/g; mean--918 eggs/g). The Yemeni had been migrating to the USA for the past 20 years, a period in which the prevalence of schistosomiasis had remained constant in the Yemen. The prevalence of schistosomiasis in those who had been away from Yemen for less than 5 years was 59% with a mean egg output of 236 eggs/g, but in those away for more than 5 years (up to 20 years) it was 32% with a mean egg output of 75% eggs/g. This is in spite of the fact that 75% of the latter had returned to Yemen for short visits. Statistical analysis by the Fisher's exact probability test revealed a significantly lower egg output in those away from Yemen more than 5 years. On the basis of these findings the mean life span of the Yemen strain of Schistosoma mansoni in man was estimated to be between 5 and 10 years. The presence of disease was assessed in this population by traditional medical means without prior knowledge of the status of the infection in the individuals examined. Under these circumstances, there were no differences in symptoms such as weakness, diarrhea and abdominal pain among the uninfected proportion of the population, total infected group and a small subgroup of those most heavily infected. None of the patients had hepatomegaly and only two had splenomegaly--one lightly and the other heavily infected. Because of the toxicity of antischistosomal drugs and the lack of treatment facilities only the 22 most heavily infected (greater than 200 eggs/g) of the 122 individuals with schistosomiasis mansoni were treated with niridazole. In addition the two individuals with splenomegaly were treated with antimony dimercaptosuccinate. Side effects, though common, were not severe. Although follow-up in this migrant population was poor the nine patients examined 3 to 7 months after treatment showed a mean decrease in egg output of 97%.

Adolescent↗
PubMedDate not supplied

Elderly patients' preferences for long-term life support.

OBJECTIVE: To study elderly patients' preferences regarding mechanical ventilation and tube feeding and to compare their preferences for short-term use with their preferences for long-term use of these life support interventions. DESIGN: Interviews with patients by clinicians during routine office visits. SETTING: Hospital-based, primary care geriatrics clinic in downtown Denver, Colo. PATIENTS: Two hundred eighty-seven elderly persons (mean age, 77 years; range, 60-99 years). MAIN OUTCOME MEASURES: Preferences to use or withhold: (1) short-term mechanical ventilation; (2) long-term mechanical ventilation; (3) short-term tube feeding; and (4) long-term tube feeding. RESULTS: Of the total sample, 253 patients (88%) would prefer short-term mechanical ventilation if the chance of recovering was reasonably good but only 11 (3.5%) would prefer long-term mechanical ventilation. One hundred eighty-nine (65%) would prefer short-term tube feeding, but only 13 (4.5%) would prefer long-term tube feeding in the setting of significant cognitive impairment. CONCLUSIONS: Most elderly persons opt for short-term mechanical ventilation or tube feeding if the chance of recovering is reasonably good. Only a small minority would opt for long-term mechanical ventilation or tube feeding.

Aged↗
PubMedDate not supplied

Modified Fontan procedure for left atrial isomerism: alternative technique.

Anomalous systemic or pulmonary venous connections increase the risk and technical difficulty of the modified Fontan procedure. This report describes an alternative technique of total diversion of systemic venous return to the pulmonary artery in a child with left atrial isomerism, incorporating an extracardiac conduit between the hepatic veins and the right pulmonary artery.

Double Outlet Right Ventricle↗
PubMedDate not supplied

A novel method for chronic measurement of respiratory function in the conscious monkey.

INTRODUCTION: Chronic measurement of respiratory function in the conscious monkey has been limited by the ability to monitor pleural pressure. Previous attempts to measure pleural pressure chronically in conscious animals have involved surgical implantation of pressure-sensitive catheters directly into the pleural cavity. The success of these techniques has been limited by lung damage and/or tissue growth and encapsulation of the pressure-sensitive catheter with damping or loss of the signal. These problems have been eliminated by developing a novel surgical procedure for placement of a pressure-sensitive catheter beneath the pleural surface. METHODS: A pressure-sensitive catheter (attached to a radiotelemetry transmitter) was surgically implanted beneath the serosal layer of the esophagus within the thoracic cavity. This was accomplished by performing a midline laparotomy, making a small incision in the serosal layer of the esophagus caudal to the diaphragm, and advancing the catheter cranially along the esophagus and beneath the serosal layer into the thoracic cavity. The catheter was secured to the esophageal wall and the telemetry transmitter was sutured to the inner abdominal wall. Respiratory airflow measurements were obtained using a restraint chair equipped with a clear plastic helmet (plethysmograph chamber) that seals around the neck and encloses the head. RESULTS: The decreases in pleural pressure during inspiration ranged from -5 to -15 mmHg and remained constant for at least 36 weeks following surgery. Intravenous administration of the respiratory depressant morphine, exposure to the respiratory stimulant 8% CO2, and intravenous administration of the bronchoconstrictive agent methacholine verified that this technique was able to detect and quantify ventilatory changes and an increase in airway resistance. DISCUSSION: This novel method for chronic measurement of pleural pressure will facilitate evaluation of the effects of drugs, environmental agents, or disease on respiratory function by allowing repeated measurements of both ventilatory (breathing) patterns and the mechanical properties of the lung in a conscious nonhuman primate.

Airway Resistance↗
PubMedDate not supplied

The effects of methylprednisolone on normal and monocyte-conditioned medium-treated articular cartilage from dogs and horses.

OBJECTIVE: To study in vitro (1) the dose-response relationships between proteoglycan metabolism in normal and corticosteroid-treated articular cartilage; (2) long-term proteoglycan metabolism after treatment of articular cartilage with corticosteroids; and (3) the effect of corticosteroids on proteoglycan metabolism in articular cartilage treated with monocyte-conditioned medium (MCM). STUDY DESIGN: Equine and canine articular cartilage explants were treated with corticosteroids and MCM. Proteoglycan synthesis and degradation were measured by radioactive labeling in short-term culture, and the long-term effect of corticosteroid treatment on proteoglycan metabolism was studied in normal explants. ANIMALS: Two young cross-breed horses and 3 young Labrador retrievers. METHODS: Equine articular cartilage explants were incubated in medium containing methylprednisolone sodium succinate (MPS) at 0, .001, .01, .1, 1, and 10 mg/mL (final concentration) for 1 day and then in fresh medium without MPS. Proteoglycan synthesis was measured by incorporation of sodium [35S]sulfate at 1, 3, 7, 10, and 13 days after initial treatment with MPS. Proteoglycan release was measured from separate explants prelabeled with sodium [35S]sulfate and treated similarly. Equine articular cartilage explants were treated with equine MCM simultaneously with, and 24 hours before MPS, at 0, 0.01, 0.1, 1, or 5 mg/mL for 72 hours. Proteoglycan synthesis and degradation in these explants was compared. Proteoglycan synthesis and degradation were measured similarly in canine articular cartilage explants treated simultaneously with canine MCM and MPS at 0, 0.001, 0.01, 0.1, 1 and 10 mg/mL for 72 hours. Equine articular cartilage explants treated with 0, 0.01, 0.1, 1, and 5 mg/mL of MPS for 72 hours were evaluated histologically. RESULTS: Proteoglycan synthesis in normal equine articular cartilage was severely depressed by 10 mg/mL MPS for 24 hours, and proteoglycan synthesis failed to recover after 13 days of culture in medium without MPS. Cartilage treated with 5 mg/mL MPS had pyknotic chondrocyte nuclei and empty lacunae. Concentrations of 1 and 0.1 mg/mL MPS depressed proteoglycan synthesis in normal equine cartilage explants. For these 2 concentrations, proteoglycan synthesis recovered 2 days after MPS removal and increased significantly (P < .05) 7 days after treatment with MPS compared with controls without MPS. Concentrations of 0.001 and 0.01 mg/mL MPS did not significantly affect proteoglycan synthesis in normal equine cartilage explants. Cumulative proteoglycan loss over 13 days in culture from normal equine explants treated for 24 hours with different concentrations of MPS was not significantly different between treatment groups at any time point. MCM significantly depressed proteoglycan synthesis in both canine and equine articular cartilage explants and significantly increased proteoglycan release. These effects were prevented in the canine explants by simultaneous treatment with MPS at 1 and 0.1 mg/mL, and proteoglycan release induced by MCM in equine articular cartilage was inhibited by 1 mg/mL MPS. CONCLUSIONS: Concentrations of 1.0 and 0.1 mg/mL MPS alleviated articular cartilage degradation in MCM-treated articular cartilage in vitro. These concentrations of MPS in contact with normal cartilage explants for 24 hours are unlikely to be detrimental in the long term to proteoglycan synthesis. The response of articular cartilage to MPS was affected by treatment with MCM so that results of experiments with normal articular cartilage explants may not reflect results obtained with abnormal cartilage. CLINICAL RELEVANCE: It may be possible to find an intraarticular concentration of corticosteroid that protects articular cartilage against cytokine-induced matrix degradation yet not have prolonged or permanent detrimental effects on chondrocyte matrix synthesis.

Analysis of Variance↗
PubMedDate not supplied

Negative pressure pulmonary edema as a post-anesthetic complication associated with upper airway obstruction in a horse.

An 8-year-old Trakehner mare developed fulminant pulmonary edema following suspected upper airway obstruction 50 minutes into an otherwise unremarkable anesthetic recovery after surgery for left cricoarytenoideus dorsalis muscle reinnervation and ventriculocordectomy. Establishing a patent airway by orotracheal reintubation and cardiopulmonary resuscitation attempts were unsuccessful. Gross, histological, and electron microscopic postmortem examination showed severe hemorrhagic pulmonary edema. Laryngeal swelling or hemorrhage were not evident, suggesting laryngospasm or functional airway collapse associated with the underlying left laryngeal paralysis, as a cause of the upper airway obstruction. Negative pressure pulmonary edema is rarely reported in the veterinary literature as a postanesthetic complication.

Airway Obstruction↗
PubMedDate not supplied

Paranasal sinus surgery through a frontonasal flap in sedated, standing horses.

OBJECTIVE: To report experience with paranasal sinus surgery through a frontonasal flap in sedated, standing horses. STUDY DESIGN: Treatment of 10 horses with naturally occurring paranasal sinus disease through a frontonasal bone flap created with the horses standing. ANIMALS: Ten adult horses. METHODS: After restraint and sedation, local anesthetic was injected subcutaneously along the proposed incision line over the conchofrontal sinus and was instilled into the sinuses through a small hole created in the frontal bone. A 3-sided, rectangular, cutaneous incision that extended through the periosteum was created over the frontal and nasal bones. The incision was extended into the conchofrontal sinus using a bone saw, and the base of the flap, on the midline of the face, was fractured. The sinuses were explored, and the horse was treated for the disease encountered. The flap was repositioned; subcutaneous tissue and skin were sutured separately. RESULTS: The horses had few signs of discomfort during creation of the bone flap and during disease treatment. Diseases encountered included inspissated exudate in the ventral conchal sinus (five horses), feed and exudate throughout the sinuses (one horse), occlusion of the nasomaxillary aperature (one horse), polyp (one horse), osteoma (one horse), and progressive ethmoidal hematoma (one horse). CONCLUSION: In selected cases, surgery of the paranasal sinuses can be performed safely on sedated and standing horses through a frontonasal bone flap. CLINICAL RELEVANCE: Performing surgery through a frontonasal bone flap with the horse standing and sedated, rather than anesthetized, eliminates risks and expense of general anesthesia.

Analgesia↗
PubMedDate not supplied

Small computer algorithms for comparing therapeutic performances of single-plane iridium implants.

We present a uniform method for selecting an optimum implant geometry by presenting techniques for evaluating the therapeutically significant maximum dose rate (herein referred to as the "maximum dose rate"), the reference isodose (85% of the maximum dose rate), and the area enclosed by the reference isodose contour. The therapeutic performances of planar iridium implants may be compared by evaluating their respective maximum dose rates, reference isodoses , and areas within the reference isodose contours. Because these parameters are mathematically defined, they reproducibly describe each implant geometry. We chose a small microcomputer to develop these comparison algorithms so that the radiotherapist need not have large, expensive computer facilities available to conduct his own studies. The development of these algorithms led to some significant conclusions and recommendations regarding the placement of interstitial implants. Using seeds that are centrally located in the array to evaluate the maximum dose contour avoids underestimating the array's maximum dose rate. This could occur if edge or corner seeds were used. Underestimating the maximum dose rate (and hence the reference isodose contour area) may have a serious therapeutic outcome, because the actual total treatment dosage may be excessive. As ribbon spacing is increased, there is a point beyond which the reference isodose contours become decoupled. At this point, a single relatively uniform reference isodose contour separates into several contours. This effect not only complicates the planimetry calculations, but it also adversely affects the therapeutic efficacy of the implant by producing therapeutically "cold" regions.

Brachytherapy↗
PubMedDate not supplied

Hypoplastic left heart syndrome.

Hypoplastic left heart syndrome (HLHS) is a complex combination of cardiac malformations that probably results from multiple developmental errors in the early stages of cardiogenesis and that, if left untreated, invariably proves fatal. A variety of chest radiographic findings are seen in patients with HLHS, including an enlarged cardiac silhouette (notably a prominent right atrium), pulmonary venous hypertension, an atrial septal defect, and valvular stenosis or atresia. The recent evolution of palliative surgical procedures (modified Norwood procedure, bidirectional cavopulmonary shunt, modified Fontan procedure, aortic valvuloplasty, heart transplantation) has increased the survival rate in children with HLHS. Echocardiography allows accurate assessment of the size and location of the ductus arteriosus, the hemodynamics of the aortic root, the patency and size of the foramen ovale or atrial septal defect, and the presence of a ventricular septal defect to help determine whether surgical intervention is appropriate and, if so, to facilitate planning. Pediatric radiologists now view radiologic images obtained in patients with HLHS before surgical intervention and at important intervals during treatment. Familiarity with the malformations that characterize HLHS and the surgical procedures used to enhance postnatal survival will help pediatric radiologists provide better care for patients with this relatively common pathologic condition.

Coronary Angiography↗
PubMedDate not supplied

Aortico-left ventricular tunnel in a neonate.

Aortico-left ventricular tunnel is a rare paravalvular communication between the aorta and the left ventricle resulting in severe aortic regurgitation. It originates most frequently just superior to the right sinus of Valsalva and enters the left ventricle just inferior to the right aortic valve cusp traversing the infundibular or perimembranous ventricular septum. We report our experience with this lesion presenting in a neonate on the first day of life and describe its clinical presentation, noninvasive diagnosis, and surgical management.

Aorta↗
PubMedDate not supplied

Aortic valve replacement in young patients: long-term follow-up.

Thirty-four young patients (28 male and 6 female) underwent aortic valve replacement between 1972 and 1988. Ages ranged from 11 to 20 years (mean 17.7 years). Including reimplantation in the follow-up period, 40 valves were implanted, among which were 17 (43%) St. Jude, 7 (16%) Bjork-Shiley, and 4 (10%) Carpentier-Edwards. Seven patients (18%) had tissue valve prostheses (4 Carpentier-Edwards, 3 Hancock valves). There was one hospital death (2.9%). Follow-up was obtained in 30 of the 33 hospital survivors, with a mean follow-up of 80 months. In the follow-up period, one patient (3%) had a major thromboembolic event and one patient (3%) had prosthetic valve endocarditis. Six patients (18%) required replacement of the implanted valve; three of these had received Hancock tissue valve prostheses. There were three late deaths, yielding 96% survival at 5 years and 84% at 10 years. Twenty-three of 30 survivors are currently New York Heart Association class I. Aortic valve replacement in young patients can be performed with low mortality and morbidity, and with excellent long-term results.

Adolescent↗