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Biomedical subjects

L Murray

Publications and source records attributed to L Murray.

At least 145 records · Page 8Linked to original sources
PubMed1986

Effect of long-term Intralipid administration in mice.

Intralipid was administered intravenously to mice at a level of 2 g kg-1 day-1 for 23 days. No alterations in phagocytic index, liver or spleen size were observed in the chronically injected mice as compared with control mice that received saline injections. Tissue distribution of 0.45 micron multilamellar liposomes of egg phosphatidylcholine:cholesterol (2:1) was similar in mice that had been chronically injected with Intralipid to that in control mice. Mice chronically given the same total amount of phospholipid in the form of 0.2 micron liposomes of phosphatidylcholine:cholesterol (2:1) rather than as a lipid-triglyceride emulsion showed altered tissue distribution of entrapped label with decreased liver uptake and increased splenic uptake, which is indicative of reticuloendothelial blockade. Tissue distribution of [14C]dipalmitoylphosphatidylcholine Intralipid was compared with that of [14C]dipalmitoylphosphatidylcholine 0.2 micron MLV of phosphatidylcholine:cholesterol (2:1). Intralipid was taken up 2- to 3-fold less by liver and 5- to 10-fold less by spleen than liposomes. Blood levels of Intralipid were higher than those of liposomes. [14C]dipalmitoylphosphatidylcholine Intralipid was eliminated from the body at a faster rate than [14C]dipalmitoylphosphatidylcholine liposomes. The lack of reticuloendothelial blockade caused by Intralipid as compared with liposomes appears to be related to its diminished uptake into reticuloendothelial tissues. This diminished uptake may be related to differences in apolipoprotein uptake of Intralipid, which is primarily in the form of a phospholipid monolayer, and liposomes, which have their phospholipid organized into a bilayer.

Absorption↗
PubMed1985

Abomasal size and emptying time in healthy lambs and in lambs affected by watery mouth.

Contrast radiography (barium sulphate suspension fed by stomach tube) was used to assess abomasal profile area (a reflection of tone in the abomasal wall) and the rate of abomasal emptying in healthy lambs aged four to 144 hours and in lambs affected by watery mouth. In healthy lambs abomasal profile area increased from 15.1 +/- 0.56 cm2/kg at four hours of age to 23.1 +/- 1.07 cm2/kg at 24 to 48 hours (P less than 0.001). There was no change up to 48 to 72 hours but after this age there was a substantial decrease to 12.8 +/- 0.76 cm2/kg at 120 to 144 hours (P less than 0.001). The rate of abomasal emptying decreased as abomasal profile area increased. Complete emptying of the abomasum was observed within three hours of feeding in the majority of lambs aged four hours (seven out of eight) and 120 to 144 hours (13 out of 16) but only in a minority of lambs aged 24 to 48 hours (one out of 11). In lambs affected by watery mouth (mean age [+/- se] 33 +/- 2.8 hours, n = 34) abomasal profile area was greater and the rate of abomasal emptying was slower than in healthy lambs aged 24 to 48 hours. These findings confirm the previous suspicion that watery mouth is associated with an impairment of gut motility. Abomasal emptying time was prolonged in lambs aged four hours when either ewe or cow colostrum was included with the contrast medium. A similar effect was observed in lambs aged 24 to 48 hours when cow colostrum was included. The castration of lambs aged four hours with rubber rings immediately before the administration of contrast medium had no effect on the rate of abomasal emptying.

Abomasum↗
PubMed1985

alpha-Glucosidase-albumin conjugates: effect of chronic administration in mice.

Enzyme albumin conjugates have been proposed as a means of increasing the efficacy of enzyme use in vivo and decreasing immune response to the enzyme. Particulate drug carriers, however, have a pronounced tendency to localize in the mononuclear phagocyte (reticuloendothelial) system. We have examined in mice the effect on phagocytic index, tissue distribution and organ size of continued administration of conjugates of alpha-glucosidase with either homologous or heterologous albumin. Mice received 10 X 2-mg injections of bovine serum albumin (BSA) or mouse serum albumin (MSA), either free, polymerized or conjugated with alpha-glucosidase. Experiments involving BSA had to be terminated before the end of the experiment because of anaphylaxis, but these reactions were less severe to the polymerized albumin than to free albumin. Free BSA, BSA polymer and BSA-enzyme conjugates all caused a decrease in phagocytic index after six injections. Mice receiving MSA showed no evidence of anaphylaxis, but mice receiving six or more injections of free MSA, MSA polymer or MSA-enzyme conjugate had significantly decreased phagocytic indices as compared to controls. Phagocytic indices had returned to normal by 7 days after the final injection. Tissue distribution of 125-I-labeled albumin preparations was determined in either naive or chronically injected mice.

Animals↗
PubMed1985

Effects of maternal nutrition on udder development during late pregnancy and on colostrum production in Scottish Blackface ewes with twin lambs.

Effects on udder development and colostrum production of changing the level of ewe nutrition were investigated. Udder weights at term were derived from their linear dimensions and yields of colostrum were obtained by hand milking on three occasions between one and 18 hours after birth. The linear dimensions of the udder increased progressively in all animals between 100 days of gestation and term (about 145 days), but udder development was retarded significantly within three days of the onset of underfeeding at 105 days of gestation. Underfeeding reduced the total yield of colostrum during the first 18 hours after birth by decreasing the prenatal accumulation of colostrum and its subsequent rates of secretion. Improving the ewe's nutrition from one hour after birth tended to increase the secretion rates of colostrum between 10 and 18 hours. Refeeding previously underfed ewes to high levels from about five days before birth had no effect on udder growth but did increase the prenatal accumulation of colostrum and its subsequent rates of secretion to levels which, when corrected for differences in udder weight, were similar to those of ewes which were fed well throughout. Calculations revealed that by ignoring udder growth the Agricultural Research Council recommendations for the energy requirements of pregnant ewes underestimate the cost of tissue synthesis during the last four weeks of pregnancy by about 100 per cent.

Animal Nutritional Physiological Phenomena↗
PubMed1985

Effects of maternal nutrition on the availability of energy in the body reserves of fetuses at term and in colostrum from Scottish Blackface ewes with twin lambs.

Ewes carrying twin fetuses were maintained during late pregnancy on a uniformly high plane (n = 22), a uniformly low plane (LP) (n = 24) or a low plane increasing to a high plane (n = 14) of nutrition. Seven ewes at each nutritional level were killed at 142 days of gestation and the liver and muscle glycogen and body lipid concentrations of the fetuses were determined. The rest of the ewes lambed naturally at about 145 days and the colostrum yields were obtained by hand milking after oxytocin injections during the first 18 hours after birth. The lactose, lipid and protein concentrations of colostrum were determined. Undernutrition in the LP group did not apparently affect the body concentrations of available glycogen, reduced available body lipid by about 47 per cent and reduced the lactose, lipid and protein available in colostrum during the first 18 hours by about 50 per cent. Refeeding previously underfed ewes to a high plane during the last five to 10 days of pregnancy did not improve the available reserves of glycogen or lipid in the lambs but did increase the yields of colostral constituents by about 30 per cent. The relative contributions of body reserves and colostral constituents to the maintenance of high, medium and low metabolic rates in lambs from different groups was assessed. It was concluded that under normal field conditions refeeding undernourished ewes during the last weeks of pregnancy would improve only marginally the survival potential of the lambs and that most lambs would be compelled to draw on their body glycogen reserves in order to maintain heat production during the first 18 hours after birth, even when they consumed all the available colostrum.

Animal Nutritional Physiological Phenomena↗
PubMed1984

Chronic liposome administration in mice: effects on reticuloendothelial function and tissue distribution.

Liposomes have a pronounced tendency to localize in the reticuloendothelial (RE) system, a major host defense system. We have examined, in mice, the effect of chronic i.v. administration of low to moderate liposome doses on drug metabolism, phagocytic index and spleen and liver size. Little effect on the rate of pentobarbital metabolism was noted, except when mice received 80 mg/kg of sphingomyelin-containing liposomes in a series of 10 injections over 3.5 weeks. Impairment of RE phagocytic function was found to be related to liposome size and composition, size and frequency of liposome dose and the presence of lipid peroxides. The effects on tissue distribution of liposome-entrapped [14C]sucrose was also determined in mice receiving chronic liposome injections. In RE blockaded mice there was a consistent trend in favor of decreased liver uptake and increased spleen uptake. No significant uptake of liposome contents was seen in non-RE tissues even in mice with severe RE blockade, indicating that the induction of RE blockade by predosing with empty liposomes may not be a successful strategy for increasing liposome uptake to non-RE tissues. Liver to spleen ratios of [14C]sucrose appeared to be a sensitive method for quantitating RE blockade. Sphingomyelin-containing liposomes produced the greatest RE blockade, distearoylphosphatidylcholine-cholesterol liposomes were intermediate and egg phosphatidylcholine-cholesterol liposomes produced the least impairment in RE function. Liposomes which contained 1% vitamin E as an antioxidant had slightly less effect on RE function than liposomes not containing vitamin E.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

A clinical comparison of subdural screw pressure measurements with ventricular pressure.

Simultaneous recordings of intracranial pressure (ICP) from a single-lumen subdural screw and a ventricular catheter were compared in 10 patients with severe head injury. Forty-one percent of the readings corresponded within the same 10 mm Hg ranges, while 13% of the screw pressure measurements were higher and 46% were lower than the associated ventricular catheter measurements. In 10 other patients, also with severe head injury, pressure measurements obtained with the Leeds-type screw were similarly compared with ventricular fluid pressure. Fifty-eight percent of the dual pressure readings corresponded, while 15% of the screw measurements were higher and 27% were lower than the ventricular fluid pressure, within 10-mm Hg ranges. It is concluded that subdural screws may give unreliable results, particularly by underestimating the occurrence of high ICP.

Cerebral Ventricles↗
PubMed1982

Management of traumatic intracranial haematoma.

Deciding which head-injured patients should be transferred to a neurosurgical unit can be difficult. Traditional criteria emphasise the development of deteriorating responsiveness but lead to delayed diagnosis and to avoidable mortality and morbidity. To discover if a more liberal admission policy improved results a study was conducted analysing data collected prospectively from 683 patients who had a traumatic intracranial haematoma evacuated in the Glasgow neurosurgical unit between 1974 and 1980. In the first four years, before the change in policy, mortality was 38% but decreased to 29% afterwards. This reflected a reduction in the proportion of patients who talked after injury but who deteriorated into coma before operation--that is, 31% before the change in policy, 16% afterwards. If the potential benefits of CT scanning in the management of head injuries are to be realised patients must be scanned sooner than in the past. This will usually mean that more patients should go to a neurosurgical unit and that simple criteria for transfer should be established.

Adult↗
PubMed1982

Effects of feeding ewe colostrum, cow colostrum or ewe milk replacer on plasma glucose in newborn lambs.

The plasma concentration of glucose was monitored for six hours in lambs fed either ewe colostrum, cow colostrum or milk replacer by stomach tube at one hour of age. The feeding of ewe colostrum resulted in an elevation of the mean (+/- se) plasma glucose concentration from 2 . 6 +/- 0 . 3 mmol/litre before feeding to 7 . 3 +/- 0 . 92 mmol/litre three hours after feeding and this elevation was maintained. A similar rise was observed in the lambs fed cow colostrum but this was of shorter duration. A marked hyperglycaemia was observed after the feeding of milk replacer with a maximum value of 23 . 4 +/- 1 . 33 mmol/litre three hours after feeding. The practical implications of these results are discussed.

Animal Feed↗
PubMed1982

Assessment of the consequences of subarachnoid haemorrhage.

The management of patients with subarachnoid haemorrhage depends greatly on assessment of the patient's clinical condition. Difficulty in applying currently used grading systems prompted us to conduct studies of observer variability and to attempt to identify sources of inconsistency. Observers graded 15 patients from the Hunt and Hess and Nishioka systems. Kappa statistics were used to evaluate the data. Marked observer variability was found, this being greatest when Grade 3 was selected, irrespective of the system used. When observers graded clinical summaries, similar variability was found, indicating that this was due to difficulty in matching patients' clinical states with specific levels within the grading system. The study shows that a simple and more reliable grading system is required.

Humans↗
PubMed1982

Observer variability in grading patients with subarachnoid hemorrhage.

The management of individual patients with subarachnoid hemorrhage depends greatly on assessment of the patient's clinical condition. Difficulty in applying current grading systems prompted the authors to conduct studies of observer variability and to attempt to identify sources of inconsistency. Observers graded 15 patients by both the Hunt and Hess and Nishioka systems. Considerable observer variability was found, with up to four different grades being selected for the same patient. Kappa statistics were used to evaluate the data. This method determines observer agreement occurring in excess of chance. Kappa values for each grading system showed observer agreement to be significantly better than chance, yet revealed marked observer variation. Most variation occurred when Grade 3 was selected, irrespective of the system used. In a further study where observers graded clinical summaries, similar variation occurred; therefore, inconsistency was due mainly to difficulty in matching patients with levels described in the grading system, rather than to fluctuation in the patient's clinical condition or difference in the observers' examination technique. Variability was high when patients with systemic disease or vasospasm on angiography were graded with the Hunt and Hess system. The studies show that a simpler and more reliable grading system is required, and emphasize and need for caution when interpreting the results from different published series.

Adult↗
PubMed1982

Effects of long term undernutrition of the ewe on the growth rates of individual fetuses during late pregnancy.

Fifteen ewes were fed at between 0.6 and 0.8 times the recommended rates in order to reproduce the liveweight changes observed in Scottish Blackface sheep on hill farms. The curved crown-rump length (CRL) of individual fetuses was measured daily between 90 and 142 days of gestation and fetal dimensions and placental weight were measured at 142 days. Fetal growth rate decreased progressively from about 5.9 mm per day between 90 and 111 days of gestation to about 3.6 mm per day by 130 days. At 142 days of gestation the placental weight and the fetal CRL, girth and weight were all significantly lower than in fetuses of well fed ewes. The mechanisms responsible for the reduction in fetal growth rate after 111 days of gestation and the implications for animals on hill farms are discussed.

Animal Nutritional Physiological Phenomena↗
PubMed1982

Effects on the rate of increase in fetal girth of refeeding ewes after short periods of severe undernutrition during late pregnancy.

A technique is described by which daily changes in the thoracic circumference (girth) of individual fetal sheep were observed during the last 60 to 70 days of pregnancy. The girth technique and a previously published method for measuring daily changes in the curved crown-rump length were both used to examine fetal growth responses when ewes were refed at 116 days of gestation after short periods of severe underfeeding. Refeeding ewes after nine or 16 days of severe underfeeding was associated in most cases with an immediate increase in fetal growth rate, whereas refeeding after 21 days had no effect on the rate in any fetus. Possible mechanisms underlying these effects are discussed. Using girth as an index the growth rates of individual lambs were measured before and after birth. There was a 3.3 fold increase in growth rate immediately after birth.

Animal Feed↗