Biomedical subjects
D J Buckley
Publications and source records attributed to D J Buckley.
Influence of oxidised dietary oil and antioxidant supplementation on membrane-bound lipid stability in broiler meat.
1. The effects of oxidised oil, dietary alpha-tocopherol and BHA/BHT-supplementation on the fatty acid composition of mitochondrial, microsomal and soluble protein fractions of broiler muscles, and on their lability to metmyoglobin/hydrogen peroxide-catalysed peroxidation were investigated. 2. Oxidised oil in the broiler diets induced rapid oxidation of the membrane-bound lipids and decreased their stability towards metmyoglobin-hydrogen peroxide-catalysed peroxidation. 3. Supplementation of the broiler diets with alpha-tocopherol increased the alpha-tocopherol concentrations in the microsomal and soluble protein fractions of the dark meat as well as the soluble protein fraction of the white meat. This, in turn, stabilised the membrane-bound lipids against metmyoglobin/hydrogen peroxide-initiated peroxidative changes.
Effects of oxidised dietary oil and antioxidant supplementation on broiler growth and meat stability.
1. Broilers were fed on diets containing oxidised sunflower oil, sunflower oil and sunflower oil supplemented with alpha-tocopherol, butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT). 2. Oxidised oil caused a significant reduction in broiler body and carcase weights, whereas alpha-tocopherol and BHA/BHT supplementation improved growth. 3. Meat samples from these broilers were stored at 4 degrees C and -20 degrees C and their oxidative stability evaluated. Feeding oxidised oil to broilers resulted in meat that underwent rapid oxidative changes during refrigerated and frozen storage. 4. On the other hand, dietary alpha-tocopherol and BHA/BHT supplementation increased alpha-tocopherol and BHA/BHT concentrations in meat and significantly (P less than 0.05) improved the oxidative stability of meat during refrigerated and frozen storage.
The effect of corneal grafting on vision in bilateral amblyopia.
Two children with bilateral congenital corneal opacities (sclerocornea) received unilateral corneal transplants at the ages of 4 1/2 and 16 years, respectively. Both developed reading vision and reduced nystagmus excursions.
Covert self-mutilation of oral tissues and skin by mechanical and chemical means.
A case is presented in which a patient performed persistent covert acts of self-mutilation through mechanical and chemical means. The lesions first involved the oral mucosa and then the skin and were misinterpreted as erythema multiforme and pyoderma gangrenosum, respectively.
Contribution of wood smoke to in vivo formation of N-nitrosothiazolidine-4-carboxylic acid: initial studies.
The effect of administering liquid smoke or smoked food products to rats on in vivo formation of N-nitrosamino acids was investigated. Rats treated by gavage with either cysteine, formaldehyde or nitrite excreted urine containing no detectable levels of N-nitrosothiazolidine-4-carboxylic acid (NTCA). All three precursor compounds were required for NTCA formation. Two liquid smokes, when administered to rats in combination with cysteine and nitrite also produced measurable quantities of NTCA. Ascorbate inhibited in vivo formation of NTCA by approximately 90% when given to rats simultaneously with cysteine, formaldehyde, and nitrite. alpha-Tocopherol was much less effective than ascorbate in blocking NTCA formation. When smoked bacon, smoked Swiss cheese, and chicken barbecued with a sauce containing smoke flavouring were fed to rats along with nitrate, NTCA was again detected in the urine.
Hepatitis B vaccination and Sydney dental practitioners.
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Clinicopathological presentations of oral Kaposi's sarcoma in AIDS.
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Dissociation of hypoxia-induced calcium gain and rise in resting tension in isolated rat hearts.
When isolated hearts are perfused with substrate-free hypoxic buffer for prolonged periods of time, resting tension and tissue Ca increase. These two events may be interrelated. Isolated rat hearts were used to establish whether the hypoxia-induced increase in tissue Ca can be dissociated from the rise in resting tension. Tension generation was inhibited at the start of hypoxic perfusion by adding 2,3-butanedione monoxime (BDM, 30 mM). In other experiments the Ca2+ in the hypoxic buffer was reduced from 1.3 to 0.1 mM. After 30-120 min of hypoxia, ventricular muscle was assayed for ATP, creatine phosphate, Ca, and Na, and the perfusion defect was established. Resting tension was recorded before and throughout the hypoxic perfusion. Sixty minutes of perfusion with 1.3 mM Ca2+ glucose-free hypoxic buffer caused the tissue Ca to increase (P less than 0.01). Resting tension increased by 7.9 +/- 0.6 g (P less than 0.01). Sixty minutes of perfusion with 0.1 mM Ca2+ glucose-free hypoxic buffer failed to cause an increase in tissue Ca, but resting tension increased (P less than 0.01). During perfusion with glucose-free hypoxic buffer containing 2.6 mM Ca2+ and 30 mM BDM, resting tension remained low for up to 120 min, but after 60 min Ca accumulation occurred. After 120 min of BDM-hypoxic perfusion, tissue Ca reached 11.8 +/- 0.9 mumol/g dry wt. With or without BDM, hypoxia caused an early increase in tissue Na ahead of any increase in tissue Ca.(ABSTRACT TRUNCATED AT 250 WORDS)
The stunned myocardium: effect of electrical and mechanical arrest and osmolarity.
After relatively short periods of ischemia, reperfusion for several hours, or even days, is required to facilitate complete recovery of the ATP stores and mechanical function. The term "stunned" has been applied to these hearts. In the present experiments, isolated, spontaneously beating and electrically paced rat hearts were made ischemic for 10 min and then reperfused with Krebs-Henseleit buffer (KH) for up to 30 min. On reperfusion, functional recovery was impaired and the inotropic effect of Ca2+ blunted. In these experiments, the effect of a period of electrical and/or mechanical quiescence before the ischemic episode was investigated. Electrical quiescence was obtained by raising the KH K+ concentration, whereas mechanical without electrical quiescence was obtained by lowering the KH Ca2+ concentration or adding 2,3-butanedione monoxime (BDM). Mechanical arrest caused by low Ca2+ perfusion before ischemia failed to improve functional recovery on reperfusion. However, introducing a high K+ perfusate or BDM for a few minutes before ischemia significantly improved the recovery during reperfusion. This improvement was neither caused by energy preservation nor an altered "reflow area". The improvement may be caused by the increased osmolarity of KH containing high K+ or BDM, since adding 10 mM sucrose to KH for an equivalent time before ischemia improved recovery and abolished the blunted inotropic effect of Ca2+.
Effect of chronic verapamil therapy on cardiac norepinephrine and beta-adrenoceptor density.
Experiments were undertaken to establish whether the chronic administration of verapamil, to provide a therapeutically relevant plasma level, results in a loss of cardiac norepinephrine (NE) and, if so, whether this is accompanied by a change in cardiac beta 1-adrenoceptor density, affinity, or selectivity. Adult male Sprague-Dawley rats were used. Verapamil was mixed with the food to provide a daily verapamil intake of 50 mg/kg body weight. This yielded a plasma level of 80-110 ng/ml and caused a significant but reversible decrease in left ventricular NE (77%, p less than 0.001), dopamine (43%, p less than 0.02), and 3,4-dihydroxyphenylethyleneglycol (30%, p less than 0.02). Cardiac membranes prepared from rats maintained on standard (control) diet contained a single population of high affinity beta 1-adrenoceptor binding sites, with an affinity (Kd) of 0.24 +/- 0.02 nM and a density (Bmax) of 35.5 +/- 19.5 fmol/mg protein. Including verapamil (dissolved in either ethanol or water) in the diet for less than or equal to 6 weeks had no effect on the Kd, Bmax, or selectivity of these sites. However, the ethanol containing, but not the ethanol-free, placebo diet caused a small (p less than 0.05) reduction in Bmax after 6 but not after 2 weeks treatment. These results show that the chronic oral administration of verapamil to provide a clinically relevant plasma level depletes the cardiac stores of NE by 77% without causing an increase in beta 1-adrenoceptor density during 6 weeks therapy.
Patient perception of cardiovascular surgical patient education.
After surgery, 100 adult cardiac surgical patients participated in a study to determine what information was important to them and how well prepared they were. Questionnaires were administered 5 to 10 days after surgery and 1 to 4 weeks after discharge. In general patients received information that they perceived to be important, and they believed that preparation was more than adequate. Patients indicated a need to know more information about medication side effects than they received, and they did not desire as much information about emotional changes or sexual activity as the literature suggested.
Oral complications of high-dose melphalan in multiple myeloma.
Four patients with multiple myeloma refractory to conventional chemotherapy received high-dose melphalan. All experienced multiple oral complications. Extensive neutropenic ulceration and orofacial herpes simplex virus infection caused considerable morbidity in three patients during prolonged periods of neutropenia.
The value of exfoliative cytology in the diagnosis of oral herpes simplex infection in immunosuppressed patients.
Conventional exfoliative cytology was effective in confirming a clinical suspicion of oral mucosal infection by herpes simplex virus in nineteen out of twenty (95%) immunosuppressed patients who were studied.
Selective anesthesias of peripheral branches of the trigeminal nerve due to odontogenic infection.
Infection of dental origin may induce anesthesias of peripheral branches of the trigeminal nerve and should be considered in the differential diagnosis of such neuropathies. This article presents two cases in which focal odontogenic infection caused sensory disruption at peripheral points along the maxillary and mandibular divisions of the trigeminal nerve. In both cases resolution of symptoms followed extraction of teeth responsible for the infection.
Control of bleeding in severely uremic patients undergoing oral surgery.
The roles of hemodialysis and 1-deamino-8-D-arginine vasopressin (DDAVP) in the control of hemorrhage following oral surgery in a severely uremic patient are described.
A computer-interfaced photometer and systematic spacing of duplicates to control within-plate enzyme-immunoassay variation.
A Multiskan photometer for reading microtiter plate enzyme immunoassays was linked with a time sharing computer to facilitate control of assay variation and analysis of results. The interface that converted photometer output to RS-232-C format required changes to divide the output into segments short enough for input to the computer. To measure within-plate variation and investigate how the method of allocating sample duplicates to plate wells may affect the estimation of sample variance, uniformity tests were conducted with 47 plates. Coefficients of variation (CV) among wells within-plates ranged from 4.6 to 20.7% and in two-thirds of the plates exceeded 10%. Duplicates allocated to adjacent wells (method 1) gave consistently higher CV for sample means than duplicates allocated to opposite plate quadrants (method 2). In general, the CV by method 2 was about 30% smaller than that by method 1. Analysis of variance confirmed the effectiveness of the quadrant pattern of duplicate allocation as a method of controlling variation that arises from well position effects.
A system for studying biorhythms in domestic sheep in confinement.
A system is described for studying biorhythms in domestic sheep. One animal in each of four temperature and light controlled rooms can be studied in pens designed to permit continuous monitoring of eating, drinking, walking, resting, body temperature and cardiac rate. Automated data acquisition, including analog-to-digital conversion, is controlled with a minicomputer. Digitized data are recorded on magnetic and punched paper tape. Data processing on large scale computers includes editing, summarisation, machine plotting and time-series statistical analysis of the period, amplitude and phase of the biorhythms.