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Biomedical subjects

E M Walsh

Publications and source records attributed to E M Walsh.

15 recordsLinked to original sources

Intravital microscopy: a new in vivo technique for visualizing and quantifying effects of regulatory peptides on choledochoduodenal junction motility.

Using intravital microscopy, we studied the in vivo effects of regulatory peptides on choledochoduodenal junction motility in guinea pigs. During basal and hormone-stimulated periods, intravital microscopy documented rhythmic, asymmetrical, "milking" contractions of the sphincter ductus choledochi (SDC) which occurred independent of sphincter ampullae (SA) contractions or were followed by SA contractions. Cholecystokinin octapeptide (CCK-8) (greater than or equal to 0.01 micrograms/kg) increased the frequency of SDC contractions and at higher doses (greater than or equal to 0.1 microgram/kg) increased the frequency of SA contractions. Pentagastrin (greater than or equal to 1.0 microgram/kg) and secretin (10 micrograms/kg) decreased the contraction frequencies of both sphincters. Biliary manometry demonstrated similar effects of these peptides on the frequency of the SDC and SA contractions, but also showed that CCK-8 (0.1 microgram/kg) increased the amplitude of SDC and SA contractions while pentagastrin (1 microgram/kg) decreased the amplitude of only SDC contractions. Tetrodotoxin and atropine did not affect hormone-induced changes in frequency, but tetrodotoxin reduced the increase in amplitude of contraction caused by CCK-8. We concluded that intravital microscopy provides a sensitive, in vivo technique to visualize and quantify the complex motility of a small structure like the choledochoduodenal junction.

Animals↗

Biliary motility: postnatal changes in guinea pigs.

Intravital microscopy, a new in vivo technique, documented age-dependent changes in choledochoduodenal junction motility in male guinea pigs. In the guinea pig, the choledochoduodenal junction served as a pump that actively emptied its luminal contents into the duodenum. In the neonates (less than or equal to 1 wk old), this choledochoduodenal junction pump was not fully developed. Unlike the older guinea pigs, some neonates had an incompetent sphincter ductus choledochi (SDC) allowing retrograde flow of bile during ampullary contractions. While fasting, neonates had decreased frequency of SDC (1.2 +/- 0.4 contractions/min) and ampullary (0.1 +/- 0.1 contractions/min) contractions as compared to juveniles (4-6 wk old) (SDC = 6.4 +/- 1.0; ampulla = 1.2 +/- 0.2 contractions/min) and adults (greater than 1 yr old) (SDC = 6.7 +/- 1.6; 0.8 +/- 0.2 contractions/min). Following a meal (Ensure), unlike older guinea pigs, the neonate did not have a significant increased duration and decreased frequency of SDC contractions. Altered neonatal SDC motility correlated with an incompletely developed SDC including decreased muscle mass and mucosal thickness. By 4 wk of age, choledochoduodenal junction motility was similar to that of the adult. These developmental alterations in junctional motility and structure may affect the flow of bile into the duodenum contributing to physiologic cholestasis and decreased intraduodenal bile acids seen in neonates.

Animals↗

Bronchoalveolar lavage in the newborn foal.

Two bronchoalveolar lavages, 24 h apart, were performed on 15 foals, ranging in age from 1 to 21 days. In the first lavage, a numerical deficiency in alveolar macrophages was demonstrated in foals up to 2 weeks of age when compared with older (2-3 years of age) horses. Alveolar macrophages obtained from the lungs of 2-3-day-old foals also demonstrated significant impaired chemotactic function. In the second lavage, although an increase of alveolar macrophages was noted, a dramatic increase of polymorphonuclear neutrophil (PMN) mobilization occurred in the foals, thus providing a phagocytic back-up for the alveolar macrophage host defence mechanism. In contrast, PMN response to lower respiratory tract perturbation in older horses was negligible. The results of this study suggest that the numerical and chemotactic deficiency found in alveolar macrophages of the neonate may play a role in the foal's susceptibility to respiratory disease.

Animals↗

The functional competence of uterine-derived polymorphonuclear neutrophils (PMN) from mares resistant and susceptible to chronic uterine infection: a sequential migration analysis.

The functional competence of uterine-derived polymorphonuclear neutrophils (PMNs) from 28 mares was measured for migration responsiveness by use of a chamber (filter) assay. Uterine infection was induced with Streptococcus zooepidemicus in mares considered resistant to chronic uterine infection (Grade I). In sequential analysis of uterine flushings obtained from these mares 5, 12, 15, 20, and 25 h after infection was induced, PMNs showed an initial rise at 12 h (from 5), then a general decline in migration response and in concentration of cells per ml from 12 through 25 h post-inoculation. In contrast, PMNs obtained from the uterine flushings from mares considered susceptible to chronic uterine infection (Grade III) demonstrated premature migration dysfunction 12 h after infection. Subsequent increases in functional competence of the PMNs were demonstrated at 15 and again at 25 h after induced infection. The concentration of uterine PMNs per ml from mares considered susceptible to chronic endometritis remained elevated from 12 through 25 h after inoculation, which suggests a possible continued recruitment of new PMNs from the peripheral circulation. The results of this study suggest that uterine-derived PMNs obtained from mares susceptible to chronic uterine infection have a compromised ability to migrate. This dysfunction may play an important role in rendering the endometrium (uterus) susceptible to chronic endometritis.

Animals↗

Host defense deficiency in newborn nonhuman primate lungs.

We have investigated two major aspects of the pulmonary host defense mechanism--alveolar macrophage function as a "first line of bacterial defense" and induced neutrophil migration into the lung as a "back-up defense." Chemotactic and phagocytic/killing assays revealed a functional deficiency in the alveolar macrophages of newborn primates. Serial bronchoalveolar lavage investigations revealed diminished neutrophil migration into the newborn primate lung. The overall pulmonary host defense capability in newborn primates was deficient. The results of this investigation may have direct clinical relevance to the susceptibility of newborns to infections and pneumonia.

Animals↗

Phagocytic and killing capacities of uterine-derived polymorphonuclear leukocytes from mares resistant and susceptible to chronic endometritis.

The host defense competence of uterine-derived polymorphonuclear leukocytes (PMN) from mares considered resistant (grade I uteri) and susceptible (grade III uteri) to chronic endometritis was evaluated for phagocytic and killing (bactericidal) capacities, using a fluorochrome assay. Peripheral blood PMN from noncategorized mares and from grade I and grade III mares were used as controls. Uterine-derived PMN from mares with grade I uteri were functionally competent for phagocytosis and killing of Candida albicans, whereas uterine-derived PMN from mares with grade III uteri had significantly less phagocytic and killing capacities (P greater than or equal to 0.0001). Results of the present study, together with data obtained from chemotactic responsiveness and deformability assays of a previous study, indicated an overall deficiency in the host defense mechanism of uterine-derived PMN from mares with grade III uteri obtained 12 hours after induced Streptococcus zooepidemicus infection. This deficiency may account for the susceptibility of mares with grade III uteri to chronic endometritis.

Animals↗

Comparison of peripheral blood and uterine-derived polymorphonuclear leukocytes from mares resistant and susceptible to chronic endometritis: chemotactic and cell elastimetry analysis.

The functional competence of peripheral blood and uterine-derived polymorphonuclear leukocytes (PMN) from 12 mares were analyzed for chemotactic responsiveness using a chemotactic chamber (filter) assay and for deformability by cell elastimetry analysis. Peripheral blood PMN obtained from control mares and from 8 mares experimentally inoculated via the uterus with 1 x 10(9) Streptococcus zooepidemicus had similar normal chemotactic responsiveness and were highly deformable before and at 12 hours after inoculation. Uterine PMN obtained 12 hours after uterine inoculation with S zooepidemicus from resistant mares were not as deformable as peripheral blood PMN, but were within normal functional limits. The chemotactic responsiveness of uterine PMN from these mares was normal. Uterine PMN obtained from mares considered susceptible to endometritis 12 hours after uterine infection did not have chemotactic responsiveness and were nondeformable. The results indicated profound differences in the functional competence of uterine PMN between mares considered resistant and susceptible to chronic endometritis.

Animals↗

Concanavalin a capping of rhesus monkey polymorphonuclear leukocytes.

The technique of capping, a probe designed to evaluate the fluidity and functional competence of human polymorphonuclear leukocytes (PMNs), has been successfully adapted for rhesus monkey PMNs. The capping characteristics of rhesus monkey PMNs are very similar to those of human PMNs. Utilizing this capping technique as an evaluation tool and with fetal/neonatal rhesus monkey as a functional animal model, the ontogeny of movement and chemotactic characteristics of PMNs can now be studied.

Animals↗

Infusions of minaxolone to supplement nitrous oxide-oxygen anaesthesia. A comparison with althesin.

In 19 patients, minaxolone citrate, a water-soluble steroid anaesthetic agent, has been used as a continuous infusion to supplement nitrous oxide anaesthesia. The minimum infusion rate (MIR) was found to be 11.3 micrograms kg-1 min-1 for patients premedicated with morphine 10 mg i.m. and breathing spontaneously 66% nitrous oxide in oxygen. The cardiovascular and respiratory effects were similar to those described in a previous study for Althesin administered under comparable conditions. Recovery from minaxolone was prolonged compared with Althesin, and this may be related both to the water-solubility of the drug, and to its greater apparent volume of distribution.

Adult↗

Abnormal maturation of sleep states in infants with aborted sudden infant death syndrome.

The time spent in REM, quiet, and indeterminate sleep was computed in 13 aborted SIDS infants and compared to that spent in the same sleep states, in 19 normal infants. Aborted sudden infant death syndrome (SIDS) infants were studied within a week of their aborted SIDS episode and subsequently at monthly intervals through the age of 4 months. Normal infants were studied at 1, 2, 3, and 4 months of age. Sleep staging was performed by two independent observers using electroencephalogram, electrooculogram, electromyogram and behavioral criteria. Although there was an increase in the percentage of time spent in quiet sleep with age in both normal and aborted SIDS infants, the significantly greater regression coefficients in normal infants (6.3 versus 2.9; P less than 0.01) indicate that there are differences in the two groups and suggest a maturational abnormality or delay in sleep state distribution in the aborted SIDS infants.

Age Factors↗

Policy challenges for child welfare in the new century.

Recent changes in public policy reflect increased efforts to scapegoat poor women and children and to polarize the objectives of child protection and family preservation. This article challenges various stakeholders in the child welfare field to move beyond the quick-fix solutions and bureaucratic overregulation precipitated by horror stories of child abuse in the media. The new century presents an opportunity to pursue differential intervention strategies that protect children while empowering poor families and communities.

Adoption↗