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Biomedical subjects

M Ellis

Publications and source records attributed to M Ellis.

At least 91 records · Page 5Linked to original sources
PubMed1998

Liquid crystal thermometry for the detection of neonatal hypothermia in Nepal.

We assessed the sensitivity, specificity and likelihood ratio of a low cost liquid crystal strip thermometer (LCT) compared with axillary mercury thermometry for the detection of neonatal hypothermia in Nepal. The subjects were 76 healthy newborns in the government maternity hospital of Kathmandu, Nepal in winter. The validity of LCT for the detection of neonatal hypothermia (less than 36 degrees C) showed a sensitivity of 83 per cent, specificity 96 per cent, positive predictive value 98 per cent and a likelihood ratio of 23. Use of LCT on newborns in this setting raises a measured pretest probability of first day hypothermia of 63 per cent to a post-test probability of 97 per cent. Liquid crystal thermometry is a simple, low-cost, and valid method for identifying core hypothermia in newborns. It is ideal for isolated rural communities where LCT strips could be added to delivery kits.

Female↗
PubMed1998

Effects of feeder type, space allowance, and mixing on the growth performance and feed intake pattern of growing pigs.

The effect of crowding and mixing on growth performance and feed intake pattern were investigated in growing pigs in a 4-wk study. Feeding pattern was monitored using automated feed intake recording equipment (F.I.R.E.). A total of 256 Yorkshire x Hampshire and purebred Duroc pigs (initial weight 35.8+/-.86 kg) were allocated to one of the eight treatment combinations in a 2x2x2 factorial arrangement (feeder type [conventional feeder vs F.I.R.E. feeder], space allowance [.56 vs .25 m2/pig], and mixing strategy [mixed vs unmixed; mixing at start of wk 1 and 3]). Pigs were housed in groups of eight, balanced for genotype and sex (barrows and gilts), and had free access to a corn-soybean meal diet (17% crude protein, 3,296 kcal ME/kg). There was no difference in growth performance between feeder types. Crowding and mixing had no effect on daily feed intake but they depressed growth rate by 15.7 and 7.1%, respectively, and the effects of the two stressors were additive. Gain:feed ratio was reduced by crowding (10.0%) but not by mixing. Crowded pigs made fewer (11.2 vs 15.7; SEM = .51), and longer (12.5 vs 8.9 min; SEM .41) feeder visits and had higher feed intake per visit (196.2 vs 145.5 g; SEM = 5.94) than uncrowded animals. Mixing produced changes in feeding pattern in the 1st wk after mixing but not over the 4-wk period. This study showed that crowding and mixing depressed growth rates in an additive manner and altered feeding behavior.

Animal Feed↗
PubMed1998

Growth performance of pigs subjected to multiple concurrent environmental stressors.

The effects of many single stressors have been reported, but how pigs perform when subjected to more than one or two stressors at a time, as is common in commercial swine production, has not. To study this, 256 Yorkshire x Hampshire or purebred Duroc pigs (34.7+/-.5 kg) were subjected to one of the eight treatment combinations (2 x 2 x 2 factorial) of ambient temperature (constant thermoneutral [24 degrees C] or high cycling temperature [28 to 34 degrees C]), stocking density (.56 or .25 m2/pig), and social group (static group or regrouped at the start of wk 1 and 3) during a 4-wk experiment. The temperature regimens were imposed in two adjacent mechanically ventilated rooms, and each temperature was imposed in each room across two trials. Four barrows and four gilts were assigned to each of the eight pens in the two rooms, and they always had free access to water and a corn-soybean meal-based diet. Treatments were imposed after a 7-d acclimation period at 24 degrees C and .56 m2/pig. Weight gain and feed intake were measured weekly. The main effects of each of the stressors for 4-wk ADG and ADFI were significant (P < .05). The stress of high temperature, high stocking density, and regrouping depressed 4-wk ADG by 12, 16 and 10% and ADFI by 7, 6, and 5%, respectively. Of the possible 60 stressor interactions for ADG, ADFI, and gain:feed (G:F), there were no significant three-way interactions and only six two-way interactions, suggesting that the effects of the individual stressors were additive. Accordingly, the growth rate of pigs subjected to the single stressor of high cycling temperature, restricted space allowance, or regrouping was depressed 10, 16, and 11%, respectively, and ADG of pigs subjected to all three stressors simultaneously was depressed by 31%. Stressor additivity was further corroborated by examining the effect of stressor order, or the number of stressors imposed simultaneously. As the number of stressors increased from 0 to 3, ADG, ADFI, and G:F decreased linearly. These data suggest that multiple concurrent stressors affect growth performance of pigs in a predictable fashion (i.e., additively) and indicate that avoidance or removal of a given stressor is advantageous even when other uncontrollable stressors persist.

Animal Feed↗
PubMed1998

Pork carcass composition: I. Interrelationships of compositional end points.

Thirty pork carcasses were used to evaluate the interrelationships between compositional end points and the accuracy of predicting various end points from one another. Right sides were fabricated into Boston butt, picnic, anterior belly, posterior belly, anterior loin, posterior loin, and ham. Carcass composition was determined on the right side using physical dissection and chemical analyses of soft tissue. Left sides were ground (whole-side grind). Linear measures and chemical composition were made on left sides. Using dissectable components, high (r > .85) correlations occurred between percentage of fat-free lean and percentage of lipid, percentage of dissectable fat, and lipid in the whole-side grind; between weights of dissectable lean and fat-free lean; and between weights of lipid in the whole-side grind and lipid, dissectable fat, and dissectible lean. Dissectable lean percentage and fat (percentage and weight) could be predicted using weight of lipid, weight of fat-free lean, and side weight. Any physical measure could be accurately estimated from any compositional end point (r2 = .79 to .93). Regression equations using 10th-rib linear measures and hot carcass weights predicted compositional end points with R2 > or = .80, with the exception of dissectable lean (R2 = .56).

Adipose Tissue↗
PubMed1998

Pork carcass composition: II. Use of indicator cuts for predicting carcass composition.

Right sides of 30 pork carcasses were fabricated into indicator cuts (Boston butt, picnic, anterior belly, posterior belly, anterior loin, posterior loin, and ham) and used to determine carcass composition by physical dissection and chemical analysis of soft tissue. Linear measures and chemical composition of whole-side grind were collected from left sides. Dissection of indicator cuts to predict dissectable composition of the side were much better indicators than linear measures (R2 = .70 to .94). Chemical analyses of soft tissue (lean + lipid) from the loin and anterior belly were better predictors of fat-free lean and extractable lipid composition of the side than linear measures; 89% of the variation in dissectable lean of the side was explained by the use of dissectable components of the anterior loin. The loin served as the best overall indicator cut across the various end points evaluated; 92% of the variation in dissectable lean of the side was explained using dissectable components of the shoulder. The anterior belly was a good indicator for percentage of dissectable lean, fat, fat-free lean, and extractable lipid.

Adipose Tissue↗
PubMed1998

An Apgar score of three or less at one minute is not diagnostic of birth asphyxia but is a useful screening test for neonatal encephalopathy.

OBJECTIVE: To evaluate the relationship between an Apgar score of three or less at one minute of life and the subsequent risk of developing neonatal encephalopathy (NE). DESIGN: Prospective. SETTING: The principal maternity hospital of Kathmandu, Nepal, a low income country, where over 50% of the local population deliver. METHODS: All liveborn infants over a 12 month period with a birthweight of 500 g or more were assessed by the Apgar scoring system at one minute of age. All term infants with neurological abnormalities presenting in the first day of life were systematically examined and described according to a conventionally defined encephalopathy grading system. Major congenital malformations and neonatal infections were excluded. RESULTS: Over 12 months there were 14,771 total births of a weight of 500 g or more of which 14,371 were live births and 400 were stillbirths. Of 734 infants with 1 min Apgar of three or less, 91 developed NE. The positive and negative predictive values of 1 min Apgar of three or less for NE were 11.4% and 99.9%, respectively. The probability of developing NE rose from 0.6% (amongst all infants born at this hospital) to 11.2% (amongst infants born with a one minute Apgar of three or less). CONCLUSIONS: An Apgar score of 3 or less at one minute is a useful screening test for clinically significant birth asphyxia (NE). It overestimates by eight fold the scale of the birth asphyxia problem, but identifies a high risk group requiring further observation of their neurological condition.

Apgar Score↗
PubMed1998

When immigrants are not migrants: counting arrivals of the foreign born using the U.S. census.

"This paper compares characteristics of recent immigrant arrivals in the United States using two measures from the decennial U.S. census: the came-to-stay question and the migration question.... Among recent arrivals, defined as those who reported they came to stay in the quinquennium preceding the census, a large number were resident in the United States five years before the census date. Furthermore, the proportion of recent arrivals present in the United States five years before the census increased between 1975-1980 and 1985-1990.... Generally, in both the 1975-1980 and 1985-1990 cohorts, those resident in the United States five years before the census have significantly less schooling and lower incomes than those who were abroad."

Americas↗
PubMed1997

Characterization and chromosomal localization of PTPRO, a novel receptor protein tyrosine phosphatase, expressed in hematopoietic stem cells.

Hematopoietic stem cells (HSCs) support blood cells throughout life by utilizing their self-renewing and multilineage differentiating capabilities. Hematopoietic growth factors mediate their effects on stem cells by the tyrosine phosphorylation of proteins. Regulation of tyrosine phosphorylation is partially mediated by protein tyrosine phosphatases (PTPases). A possible mechanism by which hematopoietic stem cells maintain their self-renewing capacity and undifferentiated state is by controlling the balanced and opposing actions of protein tyrosine kinases (PTKs), receptors for growth factors, and PTPases. We have characterized the expression of PTPases in 5-fluorouracil (5-FU)-treated murine bone marrow cells, which represent a very primitive population of progenitors enriched for reconstituting stem cells, by using a consensus polymerase chain reaction (PCR) method. Several PTPases were expressed abundantly in the 5-FU-treated bone marrow stem cells. A novel PTP, termed protein tyrosine phosphatase receptor omicron (PTPRO), which is related to the homotypically adhering kappa, mu and PCP-2 receptor-type tyrosine phosphatases, was identified and characterized. We have cloned the murine and full-length human PTPRO cDNAs which share 89% homology, indicating that PTPRO is highly conserved between these species. The human PTPRO cDNA clone encodes a polypeptide of 1439 amino acids (aa) and has a calculated molecular mass of approximately 162 kDa. PTPRO consists of an extracellular segment containing a MAM domain, an immunoglobulin (Ig) domain, four fibronectin-type III (FN-III) repeats, a transmembrane segment, and two tandem intracellular PTP domains. The human PTPRO gene was assigned to human chromosome 1p35-pter using Southern blot analyses of genomic DNAs from rodent/human somatic hybrid cell lines containing human chromosome 1 or the p35-pter region of the chromosome. The mouse Ptpro gene was mapped to chromosome 4, closely linked to D4Mit16 and Elp1 (elliptocytosis-1), by using genomic DNAs from a (C57BL/6J x Mus spretus)F1 x Mus spretus backcross. In fetal tissues, PTPRO expression was observed in the brain and lung, whereas lower levels were observed in the kidney. In adult tissues, PTPRO was less restricted and was observed in the lung, heart, skeletal muscle, prostate, testis, and in various areas of the brain, indicating that PTPRO expression is developmentally regulated. Expression of PTPRO was also observed in human CD34+ bone marrow cells and 5-FU-treated murine primitive stem cells. These results suggest a potential role for PTPRO in stem cell adhesion and in mediating homophilic cell-cell interactions in other cell types.

Amino Acid Sequence↗
PubMed1997

Effect of repeated dosing on the pharmacokinetics of oral fluconazole in bone marrow transplant patients.

We examined the pharmacokinetics of fluconazole in 11 bone marrow transplant patients after multiple oral daily dose of 200 mg of this drug. Blood was sampled at different intervals on day 1, day 13, and day 27. No dose was given on day 2, day 14, and day 28 to allow the concentration-time data to be collected over 48 hours. The 24 hour urine was also collected, and fluconazole was analyzed in both plasma and urine by a high performance liquid chromatography. The plasma concentration-time data were best described by the one-compartment model with first-order absorption. The overall inter-day change and the difference between day 1 and day 27 in the rate constant for absorption (ka), peak plasma concentration (Cmax), through plasma concentration (Cmin), time-to-peak (tmax), area-under-the-curve 0-24 (AUC0-24), rate constant for elimination (ka), mean residence time after oral administration (MRTor), and fraction of the dose excreted unchanged in urine 24 hours (fu24) were significant (P < or = 0.0029 and P < or = 0.01, respectively). However, the difference between day 1 and day 13 was significant (P < or = 0.05) only in ka, tmax, Cmax, Cmin, and AUC0-24, and between day 13 and day 27 was significant (P < or = 0.05) only in ka, Cmin, ka, and MRTor. There was no significant inter-day change in the renal clearance. The significant (P < or = 0.05) increases in Cmax, Cmin, and AUC0-24 after the dose given on day 13 as compared with day 1, and in Cmin on day 27 as compared with day 13 indicate that, in contrast to volunteers, the steady state condition was not reached on day 13 and possibly not on day 27 in these patients. This perhaps should be taken into account when prescribing fluconazole to seriously ill patients.

Adolescent↗
PubMed1997

Correlation of adenosine thallium 201 perfusion patterns with markers for inducible ischemia.

To determine the frequency of true myocardial ischemia caused by hemodynamic, metabolic, and regional functional abnormalities after intravenous adenosine infusion in patients with coronary artery disease, 13 patients--11 with coronary artery disease--received intravenous adenosine and thallium 201 during cardiac catheterization. Intracoronary adenosine levels increased by an average of 9.4-fold over baseline. Of the 11 patients, all had > or = 70% stenoses with a mean number of redistribution defects per patient of 3.3 +/- 0.7. Only two (18%) patients had new wall motion abnormalities detected by echocardiography during adenosine infusion. Pulmonary capillary wedge pressure did not significantly rise (13 +/- 7 to 17 +/- 8 mm Hg, p= NS). Lactate production occurred in two patients. Coronary sinus oxygen saturation levels rose from 29% +/- 6% to 68% +/- 8%, consistent with less myocardial oxygen extraction. Thus, despite a high prevalence of defects detected by 201Tl, the prevalence of true myocardial ischemia in patients with coronary artery disease undergoing pharmacologic stress imaging with intravenous adenosine is low. Perfusion defects induced by vasodilator stress are predominantly caused by heterogeneity of flow reserve rather than true ischemia.

Adenosine↗
PubMed1997

Duplex imaging findings predict stenosis after carotid endarterectomy.

PURPOSE: This study was performed to determine whether early duplex findings predicted restenosis after carotid endarterectomy. METHODS: One hundred ninety-two symptomatic patients who underwent carotid endarterectomy were studied with color duplex imaging at 1 day and 1 week after surgery to identify minor residual disease (causing < 50% stenosis), arterial kinking, and suture stricture, and to measure the external and luminal diameters of the carotid bulb and distal internal carotid artery. Patients were then observed prospectively with duplex surveillance for a median of 24 months to identify > 50% restenosis. RESULTS: Twenty-five stenoses > 50% of the operated carotid artery (13%) were identified, four at 1 day (residual) and 21 at a median follow-up of 6 months (restenosis). On multiple logistic regression analysis, > 50% restenosis was found to be associated with minor day-1 residual stenosis (p = 0.01) and with small luminal diameter of the distal internal carotid artery (p = 0.03) as measured 1 week after carotid endarterectomy. Life table analysis showed restenosis at 24 months to be more common for patients with below-median than patients with above-median carotid bulb external diameter (18% vs 5%, respectively; p = 0.01). CONCLUSIONS: Duplex scanning within a week of carotid endarterectomy identifies > 50% residual stenosis, in addition to minor residual 25% to 50% stenosis and small carotid dimensions, which are good predictors of > 50% restenosis at 6 months.

Adult↗
PubMed1997

Clinical follow-up rather than duplex surveillance after carotid endarterectomy.

PURPOSE: The value of duplex surveillance and the significance of contralateral carotid disease after endarterectomy have been assessed. METHODS: Three hundred five patients were observed prospectively after carotid endarterectomy for a median time of 36 months (range, 6 to 96 months), with duplex surveillance performed at 1 day; 1 week; 3, 6, 9, and 12 months; and then each year after endarterectomy. RESULTS: Thirty patients (10%) had ipsilateral symptoms (13 strokes, 17 transient ischemic attacks [TIAs]) at a median time of 6 months (range, 0 to 60 months). Life table analysis demonstrated that ipsilateral stroke was equally common for patients who had > or = 50% restenosis (3% at 36 months) and those who did not (6% at 36 months, p > 0.5). Twenty-three patients (8%) developed symptoms (stroke 5, TIA 14) attributable to the contralateral carotid artery at a median time of 9 months (range, 0 to 36 months) after endarterectomy. By life table analysis, 40% of patients with 70% to 99%, 6% with 50% to 69%, 1% with < 50% contralateral internal carotid stenosis, and 5% with contralateral carotid occlusion at the time of endarterectomy had a contralateral TIA in the 36 months after endarterectomy (p < 0.01). However, contralateral stroke was not significantly more common for patients with severe contralateral internal carotid stenosis demonstrated at the time of endarterectomy (< 50% stenosis, 0%; 50% to 69%, 3%; 70% to 99%, 7%; occlusion, 6% stroke rate at 36 months). Seven of the 32 patients who developed progression of contralateral disease had a TIA, compared with 11 of 227 patients who did not develop progression of contralateral disease (p < 0.01). None of the 12 patients who progressed from a < 70% to a 70% to 99% contralateral stenosis had a stroke. CONCLUSIONS: After carotid endarterectomy restenosis is rarely associated with symptoms; contralateral stroke is rare and is not associated with progressive internal carotid artery disease suitable for endarterectomy. This study has shown no benefit from long-term duplex surveillance after carotid endarterectomy. Selective clinical follow-up of patients who have high-grade contralateral stenoses would appear more appropriate.

Carotid Artery, Internal↗
PubMed1997

Dilatation of saphenous vein grafts by nitric oxide.

OBJECTIVES: To investigate firstly whether flow-dependent vasodilation is maintained in vein grafts, and secondly whether nitric oxide donors dilate vein grafts to improve the flow through graft stenoses. DESIGN, MATERIALS AND METHODS: The vasodilatation of mature patent vein grafts, in response to reactive hyperaemia and glyceryl trinitrate (GTN), was assessed by the change in external diameter using duplex ultrasonography. The severity (ratio of proximal systolic velocity, V1, to peak systolic velocity at the stenosis, V2, of vein graft stenoses was determined by duplex ultrasonography before and after 24 h of local application of GTN patches. RESULTS: In post-occlusion hyperaemia the diameter of patent distal vein grafts (n = 7) increased to a maximum of 112 +/- 1.9% of resting diameter after 2 min, p = 0.026. The diameter increased further to 117 +/- 2.5% of the resting value 5 min after oral GTN (n = 5), p = 0.007. The velocity ratio, V2/V1, through graft stenoses (n = 6) decreased by 20 +/- 5% after application of GTN patches, principally as a result of reduction in V2, mean difference 0.8, p = 0.15. The changes in response to GTN were more evident for proximal than distal vein graft stenoses. CONCLUSION: Flow-induced vasodilatation responses, which have been attributed to the endothelial release of nitric oxide, are maintained in patent vein grafts: the grafts dilate even further in response to GTN. The application of GTN patches close to a vein graft stenoses appears to reduce the velocity ratio through vein graft stenoses. GTN patches might be used to reduce the risk of graft occlusion when there is a delay between the detection and the treatment of haemodynamically significant graft stenoses.

Administration, Cutaneous↗
PubMed1997

Pharmacokinetics of oral fluconazole when used for prophylaxis in bone marrow transplant recipients.

The pharmacokinetics of fluconazole was investigated in 20 bone marrow transplant patients following oral administration of 200 mg of this drug. Blood samples were collected from each patient at different time intervals within 48 h after the first dose, and fluconazole was measured in plasma by high-performance liquid chromatography with UV detection. Urine was collected from 14 of these patients and analyzed similarly. The plasma concentration-time data exhibited the characteristics of the one-compartment model with first-order absorption quite well. The means +/- standard deviations of half-lives for absorption and elimination, peak concentration, time to peak, mean residence time, apparent volumes of distribution, area under the curve, and apparent oral clearance observed in these patients were 2.84 +/- 1.34 h, 19.94 +/- 18.7 h, 4.45 +/- 1.86 microg/ml, 8.34 +/- 5.97 h, 39.57 +/- 20.5 h, 0.874 +/- 0.48 liter/kg, 156.0 +/- 60.6 microg x h/ml, and 0.0256 +/- 0.0138 liter/h x kg, respectively. The amount of fluconazole excreted in urine in 24 h was 67.1 +/- 83 mg, which represents 33.55% +/- 41.6% of the dose administered. Patients who developed hemorrhagic cystitis excreted significantly (P < or = 0.0094) more fluconazole in 24 h than did those who did not.

Administration, Oral↗
PubMed1997

Feed intake pattern of group-housed growing-finishing pigs monitored using a computerized feed intake recording system.

The feed intake pattern and growth performance of boars, barrows, and gilts fed diets differing in lysine and protein content were measured on 120 crossbred pigs from 27 (SD 3.7) to 81.5 (SD 9.2) kg live weight. The pigs were housed in eight mixed-sex groups with five pigs of each sex in each group. They were fed from an electronic feed station that recorded individual meal sizes and the time and duration of visits to the feeder for each animal in the group. Four dietary treatments were compared. During the grower period (27 to 55 kg), diets ranged in lysine content form .98 to 1.31%; for the remainder of the study, lysine content was .88 to 1.18%. Barrows had a greater (P < .01) number of meals per day than the other two sexes (7.4 vs 7.0 vs 7.0 +/- .10, respectively), but there were no significant differences among sexes for daily feed intake or other feed intake traits. Daily feed intake increased with dietary lysine content, largely because of increased meal sizes resulting from longer feeder occupation times at each visit. Visits to the feeder were greatest between 0900 and 1100 and lowest between 2000 and 0400. Correlations between feeding pattern and growth traits were relatively low. Repeatabilities of feeding pattern traits were generally higher when measured over shorter time periods. These results suggest a change in feeding behavior with increasing dietary lysine levels and a relatively small effect of sex on feeding pattern for mixed-sex groups of 15 pigs fed from a single electronic feed station.

Analysis of Variance↗
PubMed1997

Incubation temperature effects on physical characteristics of normal, dark, firm and dry, and halothane-carrier pork longissimus.

Pigs (n = 18) were selected to represent three different muscle conditions (six pigs per condition): normal: dark, firm, and dry; and halothane carrier. A 45-cm-long longissimus section was excised from each side of the carcass at 30 min postmortem and cut into six sections. Right side sections were assigned to the intermediate temperature incubation (23 degrees C), and left side sections were designated high temperature incubation (40 degrees C). Sections were randomly assigned to incubation times (0, 1, 2, 4, 6, or 8 h). The 0 h section from each incubation treatment was designated as a control and was placed directly into a 4 degree C cooler. Temperature and pH were evaluated on the control section and for each loin section a the end of the incubation time. Color (L*, a*, and b* values), percentage of purge loss, water-holding capacity, and drip loss were determined. Incubation treatment did not alter pH decline in dark, firm, and dry muscle; however, high temperature increased pH decline in normal and halothane carrier samples. Results suggest that there is a strong interaction between pH and temperature that affects pork quality attributes. High incubation temperature had a negative effect on most quality variables; however, muscle condition (normal or halothane carrier) had limited effects on muscle quality.

Animals↗