Search PubMed⌕ Search

Biomedical subjects

D P Davis

Publications and source records attributed to D P Davis.

At least 37 records · Page 2Linked to original sources
PubMed1990

Pruritus and behavior of pigs infested by itch mites, Sarcoptes scabiei (Acari: Sarcoptidae).

Effects of infestation by Sarcoptes scabiei (De Geer) on pruritus and other behaviors of pigs for 9-13 wks after weaning were evaluated. Regardless of the dose of mites inoculated, pigs fed ad lib. spent approximately 60% of their time at rest. Within their average day, pigs spent more time eating in morning and evening, were more active and pruritic at midday, and rested more and spent the least time drinking water at night. Mite infestations increased total activity and time spent scratching and rubbing. Infested pigs sprayed with water rubbed and scratched 4-10 times more frequently than those left undisturbed or disturbed by other means. Pigs receiving inoculating doses of 1,000 mites became more pruritic than pigs receiving 100 mites, and both groups developed more pruritus than non-infested control pigs.

Animals↗
PubMed1990

Density, location, and sampling of Sarcoptes scabiei (Acari: Sarcoptidae) on experimentally infested pigs.

Forty-eight weaned pigs were inoculated with 0 (controls), 100 (low dose), and 1,000 (high dose) itch mites, Sarcoptes scabiei (De Geer), and allowed to develop infestations for up to 10 wk. Pigs were slaughtered in sequence during the experiment to sample hides and count mites through potassium hydroxide digestion. Incipient crusted lesions occurred in ears of 4 of 16 low-dose pigs and 7 of 16 high-dose pigs, averaged less than 3 cm2 in area, and contained 86% of all females and 87% of all other mite stages found on those pigs. Crusts aside, faces had the highest mite densities among six body regions in both infested groups. Overall, high-dose pigs had higher mite populations (269 compared with 39 mites on low-dose pigs), although values were not significantly different (P = 0.13). Mite populations did not grow significantly during the 10 wk, but variance increased among pigs in each dose group. A hide-sampling plan derived from these data indicates whole-body populations could be estimated by censusing only the crusts, if present. If absent, sampling mites from the face and dorsum should provide acceptable estimates of whole-body totals of females and other stages. A sample size of 13 hides from a herd will yield an estimate of mean whole-body total with a 90% CI less than or equal to 50% of the estimated mean.

Analysis of Variance↗
PubMed1990

Dynamics of swine mange: a critical review of the literature.

This paper summarizes the literature on swine mange, incorporating relevant literature on human scabies and on acarine associations with other mammals. Discussed are how mite populations affect immune development, how immune hypersensitivity affects host behavior and performance, and how immune hypersensitivity determines whether or not crusted lesions develop. Several key gaps in our understanding of swine mange are identified. The temporal pattern of immunity has not been studied beyond the 20th week of infestation. Desensitization as occurs in other host-parasite systems has not been documented. It is unclear if components of immune hypersensitivity regulate mite populations. Location of mites on the body and movement of mites among hosts have not been studied. And finally, improved methods for judging the severity of mange are needed to understand the biological and economic effects of mange on the swine industry.

Animals↗
PubMed1990

Properties and clinical implications of body mass indices.

The properties of body mass indices were evaluated in a cross sectional study of the weights and heights of 5016 Chinese boys and girls aged between 3 and 18 years. Of the indices examined (weight/height (W/H), weight/height2 (W/H2), weight/height3 (W/H3) and weight/heightp (W/Hp], W/Hp was the only one that consistently showed least correlation with height, and so could be regarded as the optimal body mass index by the criterion of independence of the index from height. The exponent 'p' of W/Hp is, however, highly dependent on age; the value increases steadily between the age of 3 and 7-9 years, and then varies considerably around puberty. Only the age specific exponent ensures a lack of correlation between body mass index (W/Hp) and height. Age specific W/Hp should therefore be used in intrapopulation studies of weight or problems associated with obesity in children. Interpopulation comparison of weight and adiposity by W/H, W/H2, or W/H3 may give misleading results because of their dependence on height. Our results also suggest that the conventional weight for height charts may not be accurate enough for clinical use.

Adolescent↗
PubMed1987

Sufentanil pharmacokinetics in pediatric cardiovascular patients.

The pharmacokinetics of sufentanil were studied in 28 pediatric patients undergoing cardiovascular procedures. Patients were divided into four groups on the basis of age: neonates (0-1 month, n = 9), infants (1-24 months, n = 7), children (2-12 yr, n = 7), and adolescents (12-18 yr, n = 5). Sufentanil 10-15 micrograms/kg, was administered by IV bolus and plasma concentrations measured for up to 20 hr. A tri-exponential equation best described the time-concentration data in all patients. Clearance rate (Cl) was 6.7 +/- 6.1 ml.kg-1.min-1 (+/- SD) in neonates, which was significantly lower than the values of 18.1 +/- 2.7, 16.9 +/- 3.2, and 13.1 +/- 3.6 ml.kg-1 min-1 observed in infants, children, and adolescents, respectively. The volume of distribution at steady state (Vdss) was 4.15 +/- 1.0 L/kg in neonates, significantly greater than the values of 2.73 +/- 0.5 and 2.75 +/- 0.5 L/kg observed in children and adolescents, respectively. The elimination half-life (T1/2 beta) was 783 +/- 346 min in neonates, significantly longer than the values of 214 +/- 41, 140 +/- 30, and 209 +/- 23 min observed in infants, children, and adolescents, respectively. The plasma concentration of sufentanil at the time of additional anesthetic supplementation to suppress hemodynamic responses to surgical stimulation was 2.51 ng/ml in neonates, significantly higher than the levels of 1.58, 1.53, and 1.56 ng/ml observed in infants, children, and adolescents, respectively. The authors conclude that age-related differences in pharmacokinetic and pharmacodynamic properties of sufentanil are evident in pediatric patients with major cardiovascular disease who are undergoing cardiovascular surgery.

Adolescent↗
PubMed1986

Influence of hog lice, Haematopinus suis, on blood components, behavior, weight gain and feed efficiency of pigs.

Blood components, behavior, weight gain and feed efficiency were studied in 40 weaner pigs infested with lice and 40 left uninfested (controls). Packed cell volumes and concentrations of hemoglobin, serum proteins, leukocytes, serum globulins, and serum albumins increased significantly in both groups. Eosinophil concentrations increased and neutrophil concentrations decreased in the infested group but not in the controls. There was a significant increase in erythrocyte concentrations in the control group while the infested group's erythrocyte concentrations decreased at the middle of the experiment. Blood of infested and uninfested pigs showed no significant differences from pre-infestation values in sedimentation rates and concentrations of fibrinogen, basophils, and monocytes. Control pigs spent more time at feeders and more time active while not at feeders. Nevertheless, average daily gains (ADG) and feed efficiencies (FE) of the two groups were not significantly different. When ADG and FE were grouped by severity of Haematopinus suis infestation, pigs with more H. suis had higher ADG and better FE than pigs with fewer or no lice. The results suggest that a decrease in activity by infested pigs allows them to save energy which is then available for growth.

Animals↗
PubMed1986

A spontaneously produced lipopolysaccharide biosynthetic defect which causes both pleiotropic phage resistance and mucoid colony morphology in Salmonella anatum.

A spontaneously derived mutant of the smooth bacterial strain, Salmonella anatum A1, specifically blocks the DNA ejection function of bacteriophage E15 during infection. The mutant, AE15R-5, exhibits mucoid colony morphology but no evidence of colanic acid biosynthesis. It is resistant not only to bacteriophage E15, but also to all other smooth- and rough-specific phages which have been tested. Chemical, immunological and gel electrophoretic analyses indicate that its lipopolysaccharide (LPS) molecules fall into two categories: they are either highly truncated (probably heptoseless) or extremely large (complete LPS molecules with O-polysaccharides containing 80 or more repeat units). The antibiotic resistance pattern of AE15R-5 is roughly intermediate between that of a known heptoseless mutant, S. anatum MG4, and that of the parent strain, S. anatum A-1.

Bacterial Proteins↗
PubMed1981

Importance of the aromatic ring in adrenergic amines. 6. Nonaromatic analogues of phenylethanolamine as inhibitors of phenylethanolamine N-methyltransferase: role of pi-electronic and steric interactions.

To probe the importance of pi-electronic and steric interactions of nonaromatic analogues of phenylethanolamine as inhibitors of phenylethanolamine N-methyltransferase (PNMT), a series of norbornane and norbornene ethanolamines was prepared and evaluated as inhibitors of PNMT (liquid chromatographic-electrochemical detector assay). Previous studies indicated a major importance of hydrophobic interaction of the ring moiety attached to the ethanolamine side chain, but a possible importance of pi-complex formation could have been obscured by conformational differences among the analogues. In this study, norbornane and norbornene substituted with an ethanolamine side chain at positions 1,2-exo, and 2-endo were prepared from the corresponding aldehydes by addition of trimethylsilyl cyanide (Me3SiCN) and lithium aluminum hydride reduction. The saturated (norbornane) analogues were two times more potent as inhibitors of the enzyme than were the norbornene analogues, thus suggesting that pi-complex formation is not an important contribution to binding and, as previously proposed, a hydrophobic interaction is the significant binding interaction of the ring moiety. The hydrophobic binding area has a critical size that requires the hydrophobic moiety to be of sufficient length (the bridgehead-substituted norbornane and norbornene ethanolamines being too "'short" for optimal binding). The 2-exo orientation of the ethanolamine side chain was preferred to the 2-endo orientation, supporting our earlier hypothesis that the ring moiety prefers to be oriented away from the side chain.

2-Hydroxyphenethylamine↗
PubMed1976

Novel analogs of tricyclic psychopharmacological agents.

The synthesis of several novel analogs of amitriptyline and chlorprothixene, in a number of which the position of the side-chain nitrogen atom rigidly fixed with respect to the tricyclic nucleus, is described. The compounds were evaluated for antidepressant-like activity in the Dopa and serotonin interaction tests and for potential antipsychotic activity in the methamphetamine interaction test. 5-(3-Dimethylaminocyclohex-1-enyl)-5H-dibenzo[a,d]cycloheptene (12) was about equipotent with imipramine in the Dopa and methamphetamine tests, and 3-chloro-10,11-dihydro-5H-dibenzo[a,d]cycloheptene-5-spiro-6'-3'-methyl-3'-azabicyclo[3.1.0]hexane (23) also displayed marked activity in the same tests. Prototype compounds for other ring systems, 3-(10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ylidene tropane (16) and 5-(3-dimethylaminocycloheptylidene)-10,11-dihydro-5H-dibenzo[a,d]cycloheptene (18), were less active.

Amitriptyline↗
PubMedDate not supplied

Ethylene glycol poisoning: case report of a record-high level and a review.

Ethylene glycol is commonly found in automobile antifreeze and a variety of other commercial products. Ingestion of ethylene glycol, either accidentally or in a suicide attempt, is characterized by severe acidosis, calcium oxalate crystal formation and deposition, and a wide variety of end organ effects that may be fatal. We present a case of a patient who ingested a massive amount of ethylene glycol in a suicide attempt and yet survived with minimal sequelae. A comprehensive review of the literature on the pathology and pathophysiology of ethylene glycol toxicity on each organ system is provided, along with information on diagnosis and current treatment recommendations.

Adult↗
PubMedDate not supplied

Ludwig's angina.

Explore the source record for details and available documents.

Humans↗
PubMedDate not supplied

Inaccuracy in endotracheal tube verification using a Toomey syringe.

The Toomey syringe and other esophageal detection devices have been shown to be highly sensitive and specific for indicating whether an endotracheal (ET) tube is in the esophagus or the trachea. Many prehospital systems use the Toomey syringe method as the major determinant in deciding whether or not to remove an ET tube after an intubation attempt. We present three cases in which various pulmonary pathologies led to false positive results; that is, Toomey syringe aspiration indicated esophageal placement when the tube was correctly positioned in the trachea. A literature review follows the case reports.

Adult↗
PubMedDate not supplied

Cricothyrotomy technique: standard versus the Rapid Four-Step Technique.

Standard cricothyrotomy technique uses a tracheal hook cephalad to the opening to stabilize the trachea during endotracheal (ET) tube passage. A newly described Rapid Four-Step Technique (RFST) uses the tracheal hook caudal to the opening to stabilize the trachea during ET tube passage. This experimental crossover trial compared standard cephalad tracheal hook traction to caudad traction as recommended by RFST in a cadaver model of cricothyrotomy. Outcome measures included the incidence of complications and the size of ET tube able to be passed with each technique. The anterior necks of 30 formalin-fixed cadavers were dissected to completely reveal the cricothyroid membranes and surrounding structures. Two emergency medicine residents performed all cricothyrotomies. Each cadaver was randomly assigned to undergo either standard open technique followed by RFST, or RFST followed by standard open technique. Standard open technique was performed using a #11 scalpel blade, a Trousseau dilator for widening the opening, and a tracheal hook held cephalad through the thyroid cartilage. RFST was performed using a #11 scalpel blade and a tracheal hook held caudad through the cricoid cartilage. Cuffed ET tubes without stylettes were passed in progressively larger sizes until significant resistance was met as determined independently by two physicians. The size of the largest ET tube passed for each technique was recorded. After each attempt the trachea was inspected for evidence of structural damage and the balloon cuff was checked to assess for cuff rupture. There were no complications with standard technique; five cadavers (16.7%) had complications with RFST including one (3.3 %) with balloon cuff rupture and four (13.3 %) with cricoid cartilage fractures. Tracheal damage prevented standard technique performance on three of the cadavers. There was no significant difference between maximal ET tube sizes for standard technique (median size 7.0, mean 6.95 mm internal diameter) versus RFST (median size 7.0, mean 6.82 mm internal diameter). We conclude that RFST may be associated with a higher incidence of complications than standard technique as demonstrated by our cadaver model of cricothyrotomy. We were unable to demonstrate a difference between the two techniques with regards to size of ET tube able to be passed.

Aged↗
PubMedDate not supplied

Nonaccidental trauma.

Explore the source record for details and available documents.

Bone and Bones↗
PubMedDate not supplied

Coccygeal fracture and Paget's disease presenting as acute cauda equina syndrome.

Paget's disease of bone affects a significant percentage of adult and elderly patients. Although generally asymptomatic, the inflammatory changes and hypervascularity of the affected bone is prone to pathologic fracture and resultant hemorrhage. Epidural hematoma is well-described with vertebral fractures and can present as acute cauda equina syndrome. We describe a case in which an elderly female with Paget's disease sustained a minor coccygeal fracture and developed local hemorrhage and edema, which caused a sacral plexopathy that presented identical to acute cauda equina syndrome. A literature review will follow.

Aged↗
PubMedDate not supplied

Use of the Trousseau dilator in cricothyrotomy.

When performing cricothyrotomy, once the initial incision has been created, the scalpel handle may be inserted into the incision and rotated, or a Trousseau dilator may be used to widen the opening. During endotracheal (ET) tube passage, the Trousseau dilator may be left in place or a tracheal hook may be inserted for tracheal stabilization. This experimental crossover trial of cricothyrotomy in a cadaver model compared: 1) scalpel handle rotation to the use of a Trousseau dilator in widening the initial incision, and 2) the use of a tracheal hook to a Trousseau dilator during ET tube passage. Part 1: Cricothyrotomy incisions were made in 30 formalin-fixed cadavers using a #11 scalpel blade. The opening was initially widened using a Trousseau dilator or a scalpel handle rotated through 360 degrees. Progressively larger ET tubes were passed using a tracheal hook for stabilization at the thyroid cartilage, and the size of the largest ET tube passed without significant resistance was recorded. Each opening was then widened using the other technique and ET tubes again passed as above. The dimensions of the opening after initial dilatation and after final ET tube passage were also recorded. Part 2: A tracheal hook inserted cephalad at the thyroid cartilage or a Trousseau dilator was used to stabilize the trachea during passage of progressively larger ET tubes, and the size of the largest ET tube passed without significant resistance was recorded. The insertion techniques were then reversed and ET tubes again passed as above. The trachea was inspected for damage and the balloon cuff checked for rupture after each attempt. Descriptive statistics were applied using a paired t-test and a chi-square analysis. We found no significant difference between the two techniques with regard to initial opening dimensions, final opening dimensions, or maximal ET tube size. There was no damage to local tissue and no balloon cuff ruptures. We found that the average size of the largest ET tube passed was significantly greater with the use of a tracheal hook (internal diameter mean 7.0 mm, median 7.0 mm) than with a Trousseau dilator (internal diameter mean 5.7 mm, median 5.5 mm). There was no damage to local tissue and no cuff ruptures. We conclude that the scalpel handle rotation technique is equal to the use of the Trousseau dilator with regard to opening size and maximal ET tube size but that use of a tracheal hook rather than a Trousseau dilator allows for passage of a larger ET tube in a cadaver model of cricothyrotomy.

Airway Obstruction↗