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Biomedical subjects

J Lopez

Publications and source records attributed to J Lopez.

At least 109 records · Page 6Linked to original sources
PubMed1991

Effects of temperature on the performance of finishing swine: I. Effects of a hot, diurnal temperature on average daily gain, feed intake, and feed efficiency.

Ninety-six crossbred barrows and gilts weighing 90 +/- .67 kg were used during a 21-d study to determine the effects of a hot, diurnal temperature (H; 22.5 to 35 degrees C) compared with a constant, thermoneutral temperature (TN; 20 degrees C) and the effects of sex (barrows vs gilts) on performance. A secondary objective included the determination of weight loss as a result of a 24-h fast immediately after the 21-d feeding study of commingled vs not commingled hogs of both environmental treatments (TN and H). Pigs housed in the hot, diurnal temperature gained 16.3% more slowly (P less than .001;.77 vs. .92 kg/d) than those in the constant, thermoneutral environment. Feed intake (FI) for the H pigs was 10.9% less (P less than .001; 3.01 vs 3.38 kg/d) than that for the TN pigs. The H pigs gained 17.6 g/d less and consumed 43.5 g/d less feed for every C degrees above 20 degrees C; however, no differences were observed for feed efficiency (F/G; 3.86 vs 4.19 kg for the TN and H pigs, respectively). Average daily gain and feed/gain (F/G) were not affected by sex. Likewise, no significant interactions of temperature x sex were observed for ADG, FI, or F/G. Weight loss (shrinkage) during the 24-h fast was not affected by commingling; however, the H pigs lost 17.5% more weight (P less than .05) than the TN pigs (3.82 vs 3.25%, respectively).

Animals↗
PubMed1991

Effects of temperature on the performance of finishing swine: II. Effects of a cold, diurnal temperature on average daily gain, feed intake, and feed efficiency.

Forty-eight crossbred barrows and gilts weighing 84.5 +/- .33 kg were used during two 21-d trials to investigate the effects of a cold, diurnal temperature (CD; -5.0 to 8.0 degrees C) compared with a constant, thermoneutral temperature (TN; 20 degrees C) and the effects of sex (barrows vs gilts) on performance. A second objective was to determine shrinkage as a result of a 24-h fast immediately after the 21-d study of hogs commingled vs those not commingled for both environmental treatments (CD vs TN). Pigs housed in the CD chamber gained 27.2% more slowly (P less than .001; 75 vs 1.03 kg/d) than those in the TN environment and consumed 5.7% more feed (P less than .05; 3.88 vs 3.67 kg/d). The lower ADG and higher feed intake (FI) exhibited by the CD pigs resulted in poorer (P less than .05) feed efficiency (F/G; 5.33 vs 3.73, respectively). A temperature x sex interaction occurred for ADG but not for FI or F/G. Twenty-four-hour shrink for the CD pigs was 16.4% less than for the TN pigs (3.72 vs 4.45%, respectively); however, commingling did not affect shrinkage.

Animals↗
PubMed1991

Family visits and different cultures.

Family visits to hospitalized patients provide a form of social support. Social support is known to buffer the effects of stress which may occur with an illness, hospitalization or treatment. The cultural background of any patient is an important variable as well as expectations and results of the hospitalization and treatment. The authors studied the effects of family visits upon physiological parameters of critically ill neuro patients. They will discuss the findings of their research which included patients of several cultures such as Native Americans, Hispanics, and Anglo American families in the samples used. As returned Peace Corps nurses, the presenters will discuss their experiences in different cultures and the role of the family with neuro patients in the areas. Cultures that will be discussed include those of Native Americans, Malaysians and Columbians. Implications for practice include transcultural nursing assessment. Factors to be included are values, beliefs, customs and social structure. This information should be utilized to provide optimal nursing care individualized to each patient and family with reference to their culture.

Cultural Characteristics↗
PubMed1989

The yeast GAL1-10 UAS region readily accepts nucleosomes in vitro.

To test if the absence of nucleosomes on the UAS region of the yeast GAL1-10 genes in vivo could be due to a low inherent affinity of this DNA for histones, DNA fragments containing the UAS and various amounts of flanking DNA were reconstituted into chromatin. Restriction enzyme and DNase I digestion analyses show that DNA in the UAS becomes protected against digestion in the reconstitutes. Thus, nucleosomes can assemble on the UAS region in vitro. The level of protection of the UAS and of the flanking DNA regions is comparable and remains so at various levels of nucleosome loading, suggesting that the UAS DNA has no tendency to exclude nucleosomes. In fact, DNase I results suggest that the UAS elements themselves preferentially bind histones.

Animals↗
PubMed1989

Analysis of IncF plasmids evolution: nucleotide sequence of an IncFIII replication region.

We determined the nucleotide sequence of RepFIII, the IncFIII replication region of the plasmid pSU316. Our data confirmed that RepFIII belongs to the RepFIIA family. The comparison of the nucleotide sequences from several RepFIIA-family plasmids revealed that pSU316 and R1 replicons are almost identical (96% similarity). Most of the differences between them are clustered in the incompatibility determinant. Analysis of the rest of the sequence suggested that the divergence between R1 and pSU316 replicons is very recent.

Base Sequence↗
PubMed1989

Flow changes in hepatic veins in congestive cardiac insufficiency. A study using pulsed Doppler US.

Ten patients with right heart failure and tricuspid regurgitation were studied with both B Scan and pulsed Doppler ultrasound. Variations in the Doppler waveforms were seen in portal vein recordings which indicated flow characteristics similar to those of hepatic veins due to transmission of retrograde pressure waves through the hepatic capillary bed. It was concluded that the pulsed Doppler will permit non-invasive determination of physiological events that may have great practical importance in the diagnosis and treatment of patients with right heart failure.

Aged↗
PubMed1989

Uremic plasma after infusion of desmopressin (DDAVP) improves the interaction of normal platelets with vessel subendothelium.

Effects of 1-deamino-8-D-arginine vasopressin (DDAVP; 0.4 microgram/kg iv) were studied in 11 patients with uremia. Bleeding time, platelet retention on glass beads, factor VIII activities, plasma catecholamine levels, and studies on platelet interaction with the subendothelium were performed before, 1 hour after, and 6 hours after DDAVP infusion. Perfusates consisting of normal washed platelets, uremic platelet-poor plasma (u-PPP) and washed red blood cells were perfused through the Baumgartner perfusion system at a shear rate of 800 sec-1. One hour after DDAVP infusion, a shortening in the bleeding time and an increase in platelet retention on glass beads were noticed in these patients (p less than 0.01). Simultaneously, plasma levels of noradrenaline, factor VIII coagulant (FVIII:C), and von Willebrand factor (vWF) activities were statistically increased. Platelet deposition and platelet aggregate formation on subendothelium were consistently increased (p less than 0.05) in perfusions carried out with blood reconstituted with u-PPP obtained 1 hour after DDAVP. The "in vitro" addition of 1 U/ml vWF or 1 U/ml vWF plus 1 U/ml factor VIII to the pretreatment u-PPP had no significant influence on the parameters that quantify platelet-subendothelium interaction. However, after the addition of 10 ng/ml noradrenaline to a similar system containing basal u-PPP, a clear improvement (p less than 0.05) in platelet deposition was noticed. Our results confirm the hemostatic effectiveness of DDAVP in patients with uremia and reveal an increased platelet interaction with subendothelium mediated by a factor present in uremic plasma after DDAVP administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

The Hollywood surgical-audit programme: a computer-based discharge and data-collection system for surgical audit.

This article describes the development of a computer-based system for the prospective collection of data for surgical audit and peer review with the generation of a surgical discharge letter. The software has been developed for an IBM personal computer and is suitable for any compatible computer. The system has potential advantages for teaching hospitals as it enables patients to obtain a definitive discharge letter on their discharge from hospital. It is also of potential benefit to surgeons who wish to collect clinical data and to audit the quality of their surgical practice.

Computers↗
PubMed1988

Oral contraceptives and cervical carcinoma in situ in Chile.

A case-control study of cervical carcinoma in situ was conducted in Santiago, Chile, to determine whether risk of this condition is altered by use of oral contraceptives. Responses to a standardized questionnaire were compared in 133 hospitalized cases and 254 age-matched controls selected from the same screening program through which the cases were detected. After controlling for the possible confounding influence of a variety of indices of sexual behavior, socioeconomic status, and prior cytological smears, no increase in risk was found in women who ever used oral contraceptives. No trend of increasing or decreasing risk was seen in relation to duration of use, up to more than 6 years of exposure, or with the passage of time from either initial or most recent exposure. An observed increase in risk in current users of oral contraceptives was not considered likely to represent a causal relationship.

Abortion, Spontaneous↗
PubMed1988

Inflammation due to surgical glove powders in the rabbit eye.

Inflammatory anterior chamber reactions secondary to contamination by talc, absorbable dusting powder (ADP), and a combination of these powders were studied in rabbits. These common surgical glove powders were introduced into the anterior chambers of 30 animals, and structural changes were observed on days 1 and 3, and at weeks 1, 4, 8, and 12. Our findings indicate that the combination of talc and ADP causes a substantially more acute inflammatory reaction than either agent used individually. Chronic granulomatous inflammation was more severe in the group that received ADP plus talc than in the group that received talc only.

Animals↗
PubMed1988

Effects of perinatal exposure to a synthetic estrogen and progestin on mammary tumorigenesis in mice.

The effects of perinatal exposure to synthetic estrogens and progestins on mammary tumorigenesis were studied in female C3H/HeN/MTV + mice. Mice were treated neonatally with 0.001 microgram/day diethylstilbestrol (DES), with 15 micrograms/day 17 alpha-hydroxyprogesterone caproate (HPC), or with oil on days 1-5 of life (birth = day 1). As adults, neonatally hormone-treated mice received long-term treatment with a synthetic estrogen and progestin combination or vehicle. Animals were palpated weekly for mammary gland tumors. The effect of treatment on the probability of tumor development was examined. Neonatal treatment with a low dose of DES increased the probability of mammary-gland tumor formation, whereas neonatal treatment with HPC had a slightly protective effect on tumorigenesis. Subsequent treatment of adult mice with synthetic steroids did not affect mammary gland tumorigenesis in neonatally DES-treated or oil-treated animals. There was a significant interaction between the effect of neonatal HPC treatment and subsequent steroid treatment on mammary tumorigenesis but examination of the data indicated that this interaction was due to the protective effect of HPC in the absence of subsequent exposure to synthetic steroids and the probability of tumor appearance in mice treated with both HPC and synthetic steroids as adults did not differ from that of neonatally oil-treated controls.

17 alpha-Hydroxyprogesterone Caproate↗
PubMed1988

The role of calcium in the regulation of [3H]hemicholinium-3 binding sites in rat brain.

The role of calcium in the regulation of sodium-dependent high-affinity uptake of choline was assessed in vitro in slices of the rat brain, by measuring the specific binding of [3H]hemicholinium-3 ([3H]HCh-3) and the uptake of [3H]choline. Depolarization with potassium of slices of hippocampus, cortex, or striatum significantly increased the specific binding of [3H]HCh-3 when compared to control slices. However, the observed potentiation of specific binding of [3H]HCh-3 was markedly inhibited by the removal of calcium from the incubation medium in cortex or hippocampus, but not in slices of striatum. Alterations in the uptake of [3H]choline directly paralleled the observed changes in the specific binding of [3H]HCh-3 in striatum of the rat and were unaffected by the reduction of calcium in the incubation medium. The inorganic calcium channel antagonists, cadmium and cobalt, but not magnesium, zinc, manganese or lanthanum, significantly inhibited the 40 mM potassium chloride-induced stimulation of the binding of [3H]HCh-3 in the striatum. Finally, the calcium ionophore A23187 significantly increased the binding of [3H]HCh-3 in slices of striatum, either in the presence or absence of calcium in the bathing medium. This study demonstrates regional differences in the role of extracellular calcium in the regulation of the uptake of choline and suggests the involvement of intracellular release of calcium in the in vitro regulation of the sodium-dependent high-affinity uptake of choline in the striatum.

Animals↗