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Biomedical subjects

C J Dunn

Publications and source records attributed to C J Dunn.

103 records · Page 6Linked to original sources
PubMed1975

Further studies on carrageenan-induced pleurisy in rats.

A study has been made of the exudate provoked by intrapleural carrageenan in rats. Various parameters have been measured including volume of exudate, numbers and types of cells. Pharmacological assay has shown the early release of histamine and 5HT into the exudate followed at later times by a release of prostaglandins, and a second release of histamine. The role of complement has been studied. Intrapleural injection of carrageenan after complement depletion produced a reduced migration of polymorphonuclear cells and also a reduction in volume of exudate. Prostaglandins remained unaffected by this treatment.

Animals↗
PubMed1975

The response of the newborn rat to injury. I. Vascular and humoral aspects.

The development of oedema in response to irritants injected into the skin, or pleural cavity of rats, has been shown to differ according to the age of rat studied. It was found that newborn rats were less responsive, with respect to oedema formation, at certain times after the injection of a particular irritant. Attempts to suppress the reactions of these animals using anti-histamines, anti-serotonin and kinin-depleting agents were less successful than in adults. Analysis of serum, plasma and exudate proteins revealed quantitative and qualitative differences between newborn and adult rats. The ability of various agents to cause increased vascular permeability in the skin of newborn rats was found to vary with the age of animal studied. Thus histamine, 5-hydroxytryptomine, cellulose sulphate and prostaglandin E2, all failed to cause increased vascular permeability in the skin of rats younger than 3 wk of age. However, lymph-node permeability factor induced increased vascular permeability in newborn (i.e., 6-hr-old) rats. An attempt was made to correlate these results with those of oedema formation following the infections of certain irritants.

Age Factors↗
PubMed1975

The response of the newborn rat to injury. II. Histopathological aspects and mononuclear cell turnover.

Histopathological investigations of skin lesions induced by subcutaneous implantation of glass coverslips were carried out in rats between birth and adulthood. Differences were found between the cellular reactions of newborn and adult rats to this irritant. An increased number of cells was found in the skin lesions of newborn rats, compared with adults. Uptake of a 30-min. pulse of tritiated thymidine by mononuclear cells was found to be higher in newborn skin lesions than in those of adult rats. The reverse was observed for the mononuclear cells adherent to implanted glass coverslips. Giant cells were less evident on coverslips removed from the skin of newborn rats.

Age Factors↗
PubMed1975

Quantitative studies on cell-mediated immunity in the pleural cavity of guinea-pigs.

Intrapleural injection of PPD into CFA-sensitised guinea-pigs produced a reaction having many of the characteristics of classical delayed hypersensitivity. Quantitative investigations of the time course of this reaction showed that it was typified by an initial delay in the onset of increased vascular permeability, which reached its peak between 12 and 18 hr. The cellular response in the pleural cavity followed a similar pattern, attaining maximum levels between 18 and 24 hr. Mononuclear cells dominated the reaction from 12 to 48 hr. The histological appearance of the lung tissue was also studied. Treatment with Cobra venom factor, a complement-depleting agent, failed to modify this reaction. Cyclic AMP levels were assayed for both the cellular and cell-free exudates.

Animals↗
PubMed1975

Pharmacological mediators of various immunological and non-immunological inflammatory reactions produced in the pleural cavity.

Intrapleural exudates have been produced in rats and guinea-pigs using calcium pyrophosphate, cell mediated immunity, reversed passive Arthus reaction and carrageenan. The intracellular concentration of various pharmacological mediators has been measured at different times during the evolution of these inflammatory responses. These have been correlated with volume of exudate and cellular migration. The significance of these findings has been discussed and the possible application to the search for new anti-inflammatory agents and their use in diagnostic procedures.

Animals↗
PubMed1975

Calcium pyrophosphate-induced pleurisy in rats: a new model of acute inflammation.

A model is described of acute inflammation in the pleural cavity of rats using calcium pyrophosphate as the irritant. This model would seem to simulate the pseudogout syndrome. It has been shown to be acute in onset, dominated by polymorphonuclear cells, complement independent. The advantage of the model is that volume of exudate, numbers and types of cells may be quantitated. Prostaglandins and cyclic AMP have been measured in the migrating cells. The significance of these findings has been discussed.

Animals↗
PubMed1975

The mast cells of the newborn rat diaphragm and their response to histamine liberators.

The mast cell population of rat diaphragm was estimated between birth and adulthood and found to rise with an increase in the age of rat studied. Degranulation of these cells was observed in rats from all age groups, following treatment with compound 48/80 and dextran. The association of mast cells with the blood vessel wall in adult rat diaphragm was not observed in the comparable tissues of newborn rats. These findings are discussed in relationship to the poor vascular permeability reactions exhibited by newborn and young rats.

Aging↗
PubMed1975

The response of the newborn rat to intraleural dextran: vascular and cellular aspects.

The development of hind paw oedema, in response to dextran injected in to the pleural cavity of rats, has been shown to differ with the age of rat studied. It was found that newborn rats were less responsive than adults, with respect to oedema formation induced by dextran. Attempts to suppress the dextran-indu.ced foot oedema using mepyramine and cyproheptadine, were successful only in rats from the adult age group. A semiquantitative analysis was made of the inflammatory cellular exudate produced by the intrapleural injection of dextran into rats of different ages. In contrast to the reaction of adult rats, it was found that accumulation of polymorphs in the pleura of newborn animals was delayed. The polymorph was the dominant cell type found in exudates induced either by intrapleural saline or dextran, in rats from the 6-hour age group. This contrasted strikingly with comparable exudates induced in adult rats, whose major cell type was the mononuclear cell (after saline), and the polymorph, followed by the mononuclear cell (after dextran). Fewer cells were observed in the reaction of 6-hour-old rats, compared with 7-day-old animals following intrapleural injection of the same volume of a 6-percent solution of dextran.

Aging↗
PubMed1975

A model for the quantitative study of Arthus (immunologic) hypersensitivity in rats.

A model of reverse passive Arthus (RPA) reaction in the pleural cavity of rats is described. The time course of development of exudate and migration of cells has been examined. It has been found to be complement dependent and dominated by polymorphonuclear cells. The reaction reaches a peak around 6 hours after challenge. Cyclic AMP levels have been measured both intracellularly and extracellularly and have been found to persist at high levels after the waning of the reaction.

Animals↗
PubMedDate not supplied

Glycemic control and cardiovascular disease in type 2 diabetes: a review.

Cardiovascular disease is the major cause of morbidity and mortality in people with Type 2 diabetes, and risk of atherosclerotic disease is markedly increased in people with diabetes compared to people with normal glucose tolerance. The excess risk can not be completely explained by increased prevalence of other cardiovascular disease risk factors such as hypertension and hyperlipidaemia in people with diabetes. This review examines the role of hyperglycemia and glycemic control in cardiovascular disease in people with Type 2 diabetes. The results of prospective observational studies and randomized controlled trials are summarized. We conclude that control of hypertension and hyperlipidemia are important to reduce risk of cardiovascular disease in people with diabetes and may be more easily achieved than tight glycemic control.

Cardiovascular Diseases↗
PubMedDate not supplied

Ultrasound diagnosis of immature cervical teratoma: a case report.

We report a case of cervical teratoma in a term female infant born to a 20-year-old white woman. There are rare tumors in neonates, occurring in approximately 1 in 20,000 to 1 in 40,000 live births. These tumors are accurately defined by ultrasound. Although benign, cervical teratomas cause respiratory compromise. In this case the tumor was removed surgically with no recurrence at the 10-month follow-up.

Adult↗