Plasma free fatty acid metabolism during storage of platelet concentrates for transfusion

New containers allow storage of platelet concentrates (PC) at 22 degrees C for up to 7 days, during which glycolytic and oxidative metabolism is vigorous. Recent evidence suggests that 85 percent of adenosine triphosphate regeneration is based on oxidative metabolism and that substrates other than glucose may be used. Because platelets can oxidize free fatty acids (FFA) as a possible source of energy during storage, the authors studied their availability, distribution, and turnover. Plasma FFA concentration was unchanged after 1 day of PC storage but significantly increased on Days 3, 5, and 7. Platelet-free plasma (PFP) stored under the same conditions as PC demonstrated a progressive increase in FFA, suggesting that some of the FFA accumulating in PC were derived from plasma rather than platelets. Indeed, during PC storage, plasma triglycerides decreased significantly, suggesting that they are a possible source of the increased levels of FFA found on Day 3 and thereafter. Thus, PC have a plasma FFA pool available continuously for oxidation during storage. Studies with radiolabeled palmitate suggested that FFA oxidation by platelets occurs during storage. The current findings show that plasma FFA could be a significant substrate for oxidative metabolism during storage of PC and that the oxidized FFA are replenished at least in part from plasma. These results may allow platelet storage to be improved, particularly in synthetic media.

Studies on the maturation of the small intestine of the fetal sheep. I. The effects of bilateral adrenalectomy

The effect of bilateral adrenalectomy at 120 d gestation on subsequent maturation of proximal and distal small intestine was investigated in chronically catheterized fetal sheep. Ten adrenalectomized and fourteen controls were examined at 136 d; some following infusion of [3H]thymidine at 3-6 d or 4 h before termination of pregnancy. Mean plasma cortisol levels were 5.3 +/- 0.7 ng/ml in the adrenalectomized group; control values ranged from 14 to 39 ng/ml level during the 2-week experimental period. Fetal body growth was significantly increased following adrenalectomy. In the small intestine, growth of mucosal structures was reduced, especially in distal regions. Villus height was significantly reduced in both regions. External muscle thickness was significantly increased in both regions. Despite these changes there was no alteration in villus enterocyte morphology, nor were there any significant changes in villus or crypt densities. The proportion of crypt cells labelled with [3H]thymidine was unaffected by adrenalectomy. In proximal regions, migration rate of labelled enterocytes declined from 12.0 to 5.83% villus height/d (P less than 0.025) after adrenalectomy; there was no change in migration rate in distal regions. The estimated renewal time was greater in both proximal and distal regions in adrenalectomized compared with control fetuses.

Optimization of spoiler gradients in FLASH MRI

The FLASH technique for fast magnetic resonance (MR) imaging often employs strong magnetic field gradients, called spoiler gradients, to dephase the transverse magnetization after it has been measured. Otherwise, image artifacts can develop. The effectiveness of spoiler gradients at suppressing these artifacts was evaluated experimentally on two-dimensional MR images of a uniform phantom and patients. It was informative to compare the magnetization immediately before the RF excitation in each phase encoding step. Only spoiler gradients in the slice selection direction were effective. Spoiler gradients that decreased steadily from a large amplitude in the first phase encoding step to zero in the last minimized the transverse magnetization and suppressed the image artifact, without changing the image contrast.

Studies on the maturation of the small intestine in the fetal sheep. II. The effects of exogenous cortisol

The effect of cortisol on small intestinal maturation was investigated in catheterized fetal sheep by infusing 2 mg cortisol/d between 105 and 115 d gestation (term ca. 147 d). This treatment resulted in a fivefold increase in plasma cortisol compared with catheterized control fetuses of the same age. There were no detectable changes in enterocyte morphology after the cortisol infusion; the size and density of most intestinal components were largely unaffected by the treatment. By contrast, the kinetics of the enterocyte population were significantly altered by the raised cortisol levels. The proportion of crypt cells labelled was significantly increased from 0.20 +/- 0.04 to 0.33 +/- 0.03 in the proximal region (P less than 0.01) and from 0.22 +/- 0.03 to 0.31 +/- 0.02 in the distal region (P less than 0.01). The migration of enterocytes in both regions was significantly increased to nearly twice the control values (P less than 0.05). Correspondingly, renewal time was almost halved in both regions, while cell density was unchanged in distal and decreased in proximal regions. Hence cell loss appeared to have increased as a result of the cortisol infusion. The kinetic parameters for the villus enterocyte population of the fetuses receiving cortisol before 115 d were of similar magnitude to those previously seen in the normal near-term fetus. To this extent exogenous cortisol treatment given before a pre-partum surge mimicked the action of the endogenous hormone in late gestation.

Study of arterial blood pressure in newborn foals using an electronic sphygmomanometer

An electronic sphygmomanometer which functions on oscillometric principles, was used to measure arterial blood pressure in foals. Its accuracy was assessed by comparison with results obtained by direct measurement in anaesthetised pony foals, aged 34 to 64 days. Correlations between data obtained by the two methods were highly significant but the sphygmomanometric readings were consistently lower than those obtained by direct measurement. An equation was derived from the pooled values for mean, systolic and diastolic pressure measurements. This was used as a correction factor when the oscillometric method was employed in the field on Thoroughbred foals, during the first three days post partum, and on pony foals during the first day only. There were no significant differences between systolic, diastolic and mean values in Thoroughbreds on Days 1, 2 or 3 after birth. Measurements recorded on the first day after foaling were significantly lower (P less than 0.025) in ponies than in Thoroughbreds. Blood pressure measurements in Thoroughbreds and ponies were substantially higher than those reported previously using the ultrasonic Doppler technique.

Autoradiographic localization of (3H)-thymidine incorporation in the small intestinal epithelium of fetal sheep

Aspects of the cell kinetics of the developing intestinal epithelium of fetal sheep were investigated by autoradiography. The sites of (3H)-thymidine uptake were localized in the small intestinal epithelium of fetal sheep from 60 to 145 days' gestation. Labeled cells were always confined to the intervillus progenitive zone, either between the bases of adjacent villi in the younger fetuses or in crypts. There were no labeled cells within the villus epithelium. Labeled and unlabeled cells within the progenitive zones were counted in proximal and distal regions of the small intestine. The proportion of cells labeled (PCL) was unaffected by the route of administration of (3H)-thymidine into the fetus. There was no clear age-related trend in PCL of the distal region (mean distal PCL, 0.23 +/- 0.03). On the other hand, in proximal regions, PCL was at its highest value at 60 days (0.33), falling to a minimum of 0.14 at 130 days, before rising to 0.25 (+/- 0.04) at 136 days. These results demonstrate that the proliferation of enterocytes in utero is qualitatively similar to that in the adult, being confined to a distinct progenitive zone. Such a finding is an important first step in understanding changes in enterocyte structure and function, since this may, as seen in the adult, be largely determined by the rates of division and renewal.

The role of ingestion in the development of the small intestine in fetal sheep

We have examined the influence of preventing the passage of swallowed fluid on the development of the small intestine during late gestation in fetal sheep. In four fetuses at 90 d of gestation, the oesophagus was ligated and fistulated, causing swallowed fluid to enter the amniotic sac. Tissue was removed from proximal and distal parts of the small intestine for histological analysis at 136 d (term is 147 d). The body weights of the four experimental fetuses were not significantly different from those of fourteen age- and breed-matched fetuses which were used as controls. However, the width of the mucosal layers at both sites in the small intestine was reduced by approximately 25% in the fistulated fetuses. This was largely attributable to a reduction in villus height of approximately 30%. The densities of villi and crypts increased significantly at the proximal and distal sites respectively. These findings indicate that the ingestion of fluid during late gestation plays a role in promoting growth of the mucosal elements of the small intestine. The way in which this occurs is not clear although it may be mediated either by trophic factors present in either amniotic or pulmonary fluid, or by the release of gastrointestinal hormones, such as gastrin, as a result of gut distension.

The effect of pancreatectomy on the uptake of metabolites by the sheep fetus

The effects of fetal pancreatectomy on the uptake of oxygen, glucose and lactate by the fetus, uterus and uteroplacental tissues were investigated in chronically catheterized sheep during the last third of gestation. Pancreatectomy reduced the uptake of glucose by the fetus but had little apparent effect on glucose uptake by the uterus or uteroplacental tissues. The mean umbilical uptake of glucose by the pancreatectomized fetuses was 10.4 +/- 1.1 mumol/kg . min (n = 4) which was significantly less than the value observed in the intact fetuses (24.5 +/- 2.7 mumol/kg . min, n = 4, P less than 0.01). When all the data from the pancreatectomized and intact fetuses were combined, there was a significant positive correlation between the plasma insulin concentration in utero and the umbilical uptake of glucose (r = 0.95, n = 14, P less than 0.01). The glucose/oxygen quotient in the pancreatectomized fetuses (0.32 +/- 0.02, n = 9) was significantly less than the value observed in the intact fetuses (0.59 +/- 0.04, n = 6, P less than 0.01). There was also a significant positive correlation between the glucose/oxygen quotient and the plasma concentration of insulin in the fetus (r = 0.73, n = 59, P less than 0.01). Pancreatectomy had no significant effect on the fetal lactate/oxygen quotient or on the uptake of oxygen or lactate by any of the tissues. These observations demonstrate that the endogenous concentration of insulin is a physiological regulator of glucose uptake by the fetal tissues.

Enterocyte migration in the foetal sheep small intestine

The migration of enterocytes was studied in the small intestine of foetal sheep at 115 and 136 days of gestation in utero. The speed of migration in all cases was slower than that reported in the adult. At 115 days, the migration rate was 4.88 and 4.96 percent villus height/day for the proximal and distal small intestine, respectively. At 136 days, the migration rate was significantly increased (p less than 0.05) to 12.0 for the proximal and to 8.5%, for the distal small intestine. Rates of villus length increase were between 0.007 and 0.012 mm/day over the time course studied. The migration rates, expressed as millimeters per day, were between 0.23 and 0.76 mm/day, hence the rate of migration was much greater (between 3 and 16 times) than the villus growth rate.

Pancreatic alpha cell function in the fetal and newborn pig

Plasma glucagon concentrations were measured in chronically catheterized fetal pigs during the last third of gestation and compared with the values observed in anaesthetized fetuses of similar gestational age. The mean plasma concentration of glucagon in the chronically catheterized fetuses was 10.0 +/- 1.4 (S.E.M.) pmol/l (n = 11; term = 114 +/- 2 days). Concentrations were increased after catheterization and fell to baseline values within 48 h of surgery. Arginine infusion evoked a rapid release of glucagon in chronically catheterized fetuses between 105 and 108 days of gestation; the mean maximum increment in plasma glucagon was 15.4 +/- 4.5 pmol/l (n = 5). Plasma glucagon concentrations increased with increasing gestational age in both anaesthetized and chronically catheterized fetuses. Between 95 and 110 days of gestation, glucagon levels were significantly higher in anaesthetized fetuses than in chronically catheterized animals with similar normal pH values. Catheterization and prematurity had no apparent effect on plasma glucagon levels at birth. The plasma concentrations at birth were similar to those observed in the chronically catheterized fetuses in utero provided the piglets did not become acidotic during delivery. Significantly higher plasma levels of glucagon were found in newborn piglets with acidaemia (pH less than 7.3) than in piglets with normal pH values at birth (pH greater than 7.3). When all the data from the newborn piglets were combined, there was a significant negative correlation (r = -0.79, n = 39, P less than 0.01) between blood pH and the plasma concentration of glucagon at birth. These observations demonstrate that the fetal alpha cells are functional and responsive in utero and at birth.

Congenital anomalies in American Indians of British Columbia

Birth prevalences of congenital anomalies in the American Indians of British Columbia are compared with those of the total British Columbia population. This study is based on data from the British Columbia Health Surveillance Registry for a 16-year period (1966-1981) judged to be the most reliable reporting period in the 35-year history of the registry. The overall congenital anomaly frequency is lower in Indians than in the general population (45 versus 60 per 1,000 livebirths). The Indian rates for individual anomalies are lower than the corresponding general population rates with the exception of orofacial clefting and congenital heart defects. Defects of the central nervous system in both populations are comparable. There is a striking paucity of hypospadias, other anomalies of the genital organs and foot deformities in Indian males. It is suggested that the differences in the congenital anomaly rates between the American Indians and the non-Indians of British Columbia may reflect genetic differences between the two groups, but differences in ascertainment and infant mortality probably also play a role.

Parameters for the operation of bacterial thiosalt oxidation ponds

Shake flask and pH-controlled reactor tests were used to determine the mathematical parameters for a mixed-culture bacterial thiosalt treatment pond. Values determined were as follows: K(m) and V(max) (thiosulfate), 9.83 g/liter and 243.9 mg/liter per h, respectively; K(i) (lead), 3.17 mg/liter; K(i) (copper), 1.27 mg/liter; Q(10) between 10 and 30 degrees C, 1.95. From these parameters, the required bioxidation pond volume and residence time could be calculated. Soluble zinc (0.2 g/liter) and particulate mill products and by-products (0.25 g/liter) were not inhibitory. Correlation with an operating thiosalt biooxidation pond showed the parameters used to be valid for thiosalt concentrations up to at least 2 g/liter, lead concentrations of at least 10 mg/liter, and temperatures of >2 degrees C.

Rubella: immunity and vaccination in schoolgirls

Of 191 schoolgirls, 128 volunteered to take part in a feasibility study of serotesting before and after rubella vaccination, and all responded to RA 27/3 vaccine. Had the serum samples been taken by a fingerprick method the number of volunteers would probably have increased considerably. A change in policy for rubella vaccination to testing both before and after vaccination would cost no more than the existing policy, would ensure primary response, and would differentiate those women who were protected by the vaccine from those with antibody to wild virus.

Endothelial regeneration. VII. Lack of intimal proliferation after defined injury to rat aorta

Rat aortas were denuded of endothelium by the use of catheters, which removed either a zone 10-15 cells wide or a zone 90-120 cells wide. Each animal received 3H-thymidine at 1, 16, and 24 hours before death, and groups of 3 animals were killed at 2, 3, 4, and 7 days after the small injury or 4, 5, 7, 14, and 42 days after the large injury. Scanning electron microscopy showed that the smaller injury was rehealed with endothelium by approximately 72 hours, and the large injury was repopulated by endothelium after 7-8 days. In aortas subjected to the 10-15-cell-wide injury, no intimal thickening nor intimal smooth-muscle proliferation was observed. After the larger injury, no obvious intimal thickening was present, although a few intimal cells were observed at sites where the internal elastic lamella was discontinuous. No significant increase in smooth-muscle-cell replication was detected in these aortas at any time after injury.

The effects of cortisol on the concentration of glycogen in different tissues in the chronically catheterized fetal pig

The effect of exogenous cortisol on glycogen deposition in a number of fetal tissues was investigated in chronically catheterized fetal pigs between 80 and 95 d of gestation (term 114 d). Intravascular infusion of cortisol for 48 h increased the fetal plasma concentration of cortisol 4-fold to a value similar to that observed in piglets near to term. After infusion of cortisol, the concentration of glycogen in the lung was lower while the levels in skeletal muscle and liver were higher than those found in unoperated fetuses. There were no detectable changes in either skin or cardiac muscle glycogen after cortisol infusion. High endogenous cortisol concentrations were observed in some of the catheterized control fetuses and in two unoperated fetuses adjacent to the site of cortisol infusion. These fetuses also had detectable changes in lung, liver and skeletal muscle glycogen. When the data from all the fetuses, whether infused, control catheterized or unoperated, were combined there was a significant positive correlation between both liver and skeletal muscle glycogen concentrations and log plasma cortisol (r = 0.70 and 0.72 respectively, P less than 0.01). Lung glycogen levels were inversely related to log plasma cortisol (r = -0.67, P less than 0.01). No relation between either cardiac or skin glycogen concentration and fetal plasma cortisol could be detected. These observations demonstrate that cortisol has a marked effect on tissue glycogen levels in the immature fetal pig and suggest that the changes in glycogen concentrations observed in the liver, lung and skeletal muscle before term may be due to the pre-partum surge in fetal cortisol.

Studies on equine prematurity 2: Post natal adrenocortical activity in relation to plasma adrenocorticotrophic hormone and catecholamine levels in term and premature foals

Adrenocortical and medullary function was investigated during the immediate post natal period in premature and full term foals. High plasma cortisol concentrations were characteristic of the term foals in the first 2 h after birth and these were accompanied by significant arteriovenous differences in plasma cortisol across the umbilical circulation at birth, indicating enhanced adrenal activity before delivery. No such arteriovenous differences were detected in the premature group and post natal changes in plasma cortisol were minimal. The apparent inability of the premature foal adrenal to secrete cortisol was not due to the lack of endogenous adrenocorticotrophic hormone (ACTH) because high levels of this hormone were found immediately after birth in both groups of foals. Tests on the sensitivity of the foal adrenal to exogenous ACTH1-24 (0.125 mg intramuscularly [im]) showed that a maximum response to this hormone could be elicited in term foals on the day of birth. Subsequently basal cortisol levels and the response of the adrenal to ACTH1-24 declined. By contrast, only a slight response was observed following the same dose of ACTH1-24 in the premature group. Exposure to Depot ACTH1-24 over 24 h enhanced the basal secretion of cortisol in both premature and term foals but no consistent response to the same ACTH test dose could be elicited in the former. A wide range of total plasma catecholamine concentrations was observed in both groups of newborn foals. The highest values were seen in acidotic animals and there was a significant inverse relationship between blood pH and total plasma catecholamine level at delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on equine prematurity 1: Methodology

This paper describes the general management of mares and foals during the perinatal period and the methodology used in a collaborative research project on equine prematurity. Sixteen mares with dated pregnancies delivered 45 foals over three breeding seasons (1981 to 1983). In the majority, parturition was induced with oxytocin and/or fluprostenol; the remainder were allowed to foal spontaneously. Pre-colostral milk analysis provided a means of assessing the pre-foaling status of the mare. All were observed and monitored before, during and after parturition and the sampling protocol for both mare and newborn foal is discussed in detail. The foals were assessed for their degree of maturity at birth using behavioural, haematological, acid-base status and other criteria; they were then assigned to groups for further study and tests.