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Biomedical subjects

D A Cross

Publications and source records attributed to D A Cross.

31 records · Page 2Linked to original sources
PubMed1987

Dermal cellular responses of helminth-free and Ostertagia ostertagi-infected calves to intradermal injections of soluble extracts from O. ostertagi L3 larvae.

Twelve calves were raised helminth-free until 9 weeks of age when six were orally inoculated with 100,000 Ostertagia ostertagi infective stage larvae (L3). Three uninfected and three experimentally infected calves received intradermal injections of sterile saline and soluble larval extract (SLE) from O. ostertagi L3 with a protein concentration ranging from 1 to 200 micrograms ml-1. Biopsies were performed 48 h post-injection. A kinetic study was performed on the remaining six calves, three infected and three uninfected, using a 100 micrograms ml-1 concentration of SLE and taking biopsies 1, 4, 8, 12, 24, and 72 h post-injection at both the saline and SLE-injected sites. All calves had an immediate wheal and increase in skin thickness at the SLE-injected sites. The numbers of eosinophils infiltrating SLE-injected sites as compared to saline-injected sites were significant in both uninfected and infected calves, but the infected calves had significant numbers to a wider range of SLE concentrations and had significantly higher numbers than uninfected calves in the kinetic study. Infected calves also had significant numbers of basophils in the dose response study at concentrations of 5 and 100 micrograms ml-1 SLE. Neutrophil infiltration was similar in both groups and was significant at SLE-injected sites early in the kinetic study. Detectable mast cells were decreased in SLE-injected sites of infected animals and perivascular accumulation of mononuclear and some polymorphonuclear cells was observed in the deep dermis of infected animals.

Animals↗
PubMed1986

Ostertagia ostertagi: excretory secretory chemotactic substance from infective larvae as cause of eosinophil locomotion.

The infective (third stage) larva of Ostertagia ostertagi produced an excretory secretory substance that is chemotactic for bovine eosinophils. The eosinophil chemotactic substance was present in supernatants of larval cultures within 6 hr of incubation in Eagle's Minimum Essential Medium containing 25 mM N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid. The substance responsible for eosinophil chemotaxis has activity in small amounts, a molecular weight (MW) greater than 2000, and is heat labile at 100 C. Bovine eosinophils appeared to have a receptor for the chemotactic excretory secretory substance which is either identical or structurally similar to the previously described eosinophil chemotactic substance present in soluble third stage larval extracts. The larval substance may cause eosinophil accumulation in the abomasal tissue of cattle with ostertagiasis.

Animals↗
PubMed1986

Lymphocyte blastogenic responses of calves experimentally infected with Ostertagia ostertagi.

Twelve 9-week-old calves were divided into four groups; two groups were maintained helminth-free as controls and the other groups were given Ostertagia ostertagi infective-stage larvae (L3) orally. One group received 100,000 L3 as a single inoculum and the other group received L3 in increasing dosages at weekly intervals for 8 consecutive weeks. The blastogenic responses to concanavalin A (Con A), phytohemagglutinin (PHA), and a soluble larval antigen from O. ostertagi (SLA) of peripheral blood lymphocytes were evaluated using tritiated thymidine incorporation into DNA as a measure of blastogenesis. The responses to Con A of all infected calves were significantly depressed while the responses to PHA were not. SLA, at concentrations of 4 micrograms ml-1 and above, caused blastogenic activity in lymphocytes from uninfected calves. Using SLA at 1 microgram ml-1 in lymphocyte cultures supplemented with autologous serum, an antigen-induced blastogenic response was detected in calves receiving serial inoculations of L3.

Animals↗
PubMed1978

Hypertension and anesthesia: cause for concern.

Our clinical experience and the literature regarding anesthetic management of the hypertensive patient are reviewed. Preoperative evaluation and treatment of all hypertensive patients, regardless of their degree of lability, is recommended. For emergency surgery on an untreated hypertensive patient, control of blood pressure with nitroprusside should be attempted before an awake or rapid sequence intubation. The evaluation of hypertension, the physiology of idiopathic hypertension, and the effects of treatment are discussed.

Anesthesia↗
PubMed1977

Decreased basal tear production associated with general anesthesia.

Basal tear production was measured by means of standardized Schirmer strips and 0.5% proparacaine hydrochloride topical anesthesia in 20 patients. Premedication with systemic diazepam (Valium) and atropine sulfate had no effect on basal tear production. General surgical anesthesia resulted in a noticeable depression of basal tear production at 10, 30, and 60 minutes following induction of the anesthesia. It is suggested that prophylactic eye care include both replacement of tears and prevention of mechanical exposure of the cornea during general anesthesia.

Adolescent↗
PubMed1977

Postoperative deaths due to unsuspected pheochromocytoma.

Two cases of postoperative death due to unsuspected pheochromocytoma are presented. Both patients exhibited signs and symptoms preoperatively which might have been attributable to a pheochromocytoma. These reports serve as a reminder of the potentially fatal consequences of inadequate evaluation of hypertensive patients before surgery.

Acidosis↗
PubMedDate not supplied

Inhibition of glycogen synthase kinase-3 by insulin mediated by protein kinase B.

Glycogen synthase kinase-3 (GSK3) is implicated in the regulation of several physiological processes, including the control of glycogen and protein synthesis by insulin, modulation of the transcription factors AP-1 and CREB, the specification of cell fate in Drosophila and dorsoventral patterning in Xenopus embryos. GSK3 is inhibited by serine phosphorylation in response to insulin or growth factors and in vitro by either MAP kinase-activated protein (MAPKAP) kinase-1 (also known as p90rsk) or p70 ribosomal S6 kinase (p70S6k). Here we show, however, that agents which prevent the activation of both MAPKAP kinase-1 and p70S6k by insulin in vivo do not block the phosphorylation and inhibition of GSK3. Another insulin-stimulated protein kinase inactivates GSK3 under these conditions, and we demonstrate that it is the product of the proto-oncogene protein kinase B (PKB, also known as Akt/RAC). Like the inhibition of GSK3 (refs 10, 14), the activation of PKB is prevented by inhibitors of phosphatidylinositol (PI) 3-kinase.

3T3 Cells↗
PubMedDate not supplied

Comparison of perceived pain with different immobilization techniques.

OBJECTIVE: To compare the locations and severities of pain generated by a hard wooden spine board vs a soft vacuum mattress splint on immobilized volunteers. METHODS: This was a prospective randomized crossover study conducted in an emergency medical services (EMS) classroom within a university teaching hospital. Participants were 18 healthy volunteers with no history of acute or chronic back pain, pregnancy, or recent analgesic use. The subjects were placed in one of three immobilization boards (hard spine board and two different vacuum splint models, identified as red and blue) for 60 minutes. At 0, 30, and 60 minutes the subjects rated their pain at multiple locations on their body using a visual analog scale (VAS). After a two-day washout period, this procedure was repeated on a different board and later a third board until all the subjects had been tested on all three boards. RESULTS: Although many pressure point locations were studied, only three had results that appeared statistically significant: the occiput, lower back, and sacrum. The hard spine board had higher mean pain scores as well as a higher percentage of subjects who reported any pain when compared with the two vacuum mattress splints. Mean scores for the 30- and 60-minute times were: occiput 2.06 and 2.78 for the hard board compared with 0.78 and 0.56 for red and 0.44 and 0.67 for blue; lower back 1.39 and 1.44 for the hard board compared with 0.28 and 1.11 for red and 0.06 and 0.17 for blue; and sacrum 1.56 and 2.06 for the hard board compared with 0.33 and 0.39 for red and 0.89 and 1.06 for blue. CONCLUSION: The hard-board method of spinal immobilization generates higher self-reported pain scale scores than the two vacuum mattresses.

Adolescent↗
PubMedDate not supplied

Implications of the effects of general anesthesia on basal tear production.

Ophthalmic preparations are frequently instilled topically to protect the eye during general anesthesia. The purpose of this study was to determine if such prophylactic precautions are warranted, as determined by the effect of general surgical anesthesia on basal tear production by the Schrimer I test. As general surgical anesthesia produced a marked depression of basal tear production, both mechanical protection and topical medications are recommended for the ocular care of patients undergoing general surgical anesthesia.

Adolescent↗
PubMedDate not supplied

Solving physician-hospital administration conflicts: a physician strategy for the '90s.

Today's health care climate creates increased potential for conflict between hospital administrators and hospital-based physicians. Voluminous regulations, increasing operating costs, professional liability exposure, changing methods of reimbursement, constraints on capital expenditures, and similar constraints on bed expansion have caused hospitals to explore new and innovative sources of revenue. Hospitals have become more eager to provide "bundled" services and health care "packages" in order to compete for discounted reimbursement contracts demanded by large-volume purchasers. While the impact of these changes is clearly felt in the private sector, similar fiscal constraints also may require university hospitals to modify their traditional role as leaders in education, research, and community service. In short, all hospitals are under intense pressure to increase revenues, reduce operating costs, and maintain the scope and quality of services provided.

Communication↗