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Biomedical subjects

P C Ryan

Publications and source records attributed to P C Ryan.

32 records · Page 2Linked to original sources
PubMed1989

Extracorporeal shockwave lithotripsy using ultrasonic imaging: urologists' experience.

The EDAP LT.01 is a second generation shockwave lithotripter which employs ultrasound imaging and piezoelectric shockwave generation. We describe the first 12 months of its use in the treatment of urinary calculi by urologists with no previous practical experience of ultrasonography. A total of 406 calculi (359 renal and 47 ureteric) in 317 patients were treated. Analgesia or sedation was not routinely used and 59% of all treatments were performed as outpatient procedures. The clearance rate of renal calculi smaller than 1 cm was 81%, while that of calculi larger than 3 cm was 80% (mean clearance 77.5%). Lithotripsy of ureteric calculi following retrograde manipulation to a renal site resulted in 94.4% clearance compared with 39% for those treated at a ureteric site; 93% of 684 lithotripsy treatments were either painless or caused only mild pain. Our experience with imaging and treating urinary calculi with the EDAP LT.01 lithotripter has been excellent. Patients are treated effectively and inexpensively as out-patients without analgesia or sedation.

Adolescent↗
PubMed1988

The effect of unilateral experimental testicular torsion on spermatogenesis and fertility.

Significant subfertility exists in patients following unilateral testicular torsion, implying bilateral testicular disease. Immunological activation has been detected after experimental torsion and the present study sought to demonstrate immunologically mediated effects on contralateral spermatogenesis following experimental torsion, as well as quantifying ipsilateral damage. Early and late effects of torsion on bilateral spermatogenesis were studied at 1 and 6 months in 10 groups each containing 20 rats. Gross and histological examination, direct immunofluorescence tests, vas deferens counts and copulation studies were performed. Severe ipsilateral damage was noted, even after brief torsion periods. No contralateral testicular effects, immunological or otherwise, were observed. Ipsilateral damage after torsion may have been underestimated. There is no damage to contralateral testicular exocrine function following unilateral experimental torsion.

Animals↗
PubMed1988

Experimental testicular torsion: fixation without parenchymal trauma.

Acute testicular torsion has been investigated using experimental models which either do not mimic torsion or cause parenchymal trauma. Valid conclusions regarding possible immunological activation cannot be made from such models. Techniques for experimental torsion in the rat are compared in this study to a standard venous occlusion model. Vascular dye injections and gross assessment were made at 0, 1 and 12 h. Testicular torsion of 720 degrees with fixation by a transmesorchial suture was the model which produced changes most similar to those in the venous occlusion model. This model causes torsion without parenchymal trauma and mimics acute testicular torsion more accurately than previously existing models.

Animals↗
PubMed1988

The vas deferens count: a new accurate method for experimental measurement of testicular exocrine function.

Clinical and experimental measurement of fertility presents difficulties in technique and interpretation of results. This study compared a new concept, the vas deferens count (VDC), with the standard electroejaculation method as a means of measuring testicular sperm output. Seventy-five Wistar rats in three groups (control, orchidectomy, torsion) underwent VDC and electroejaculation fertility analyses. The VDC was successful in all cases and gave rise to results showing acceptable variance and, in addition, measured unilateral testicular exocrine function in each case. Electroejaculation was found to be a less satisfactory technique. The VDC is a simple and accurate technique for measuring testicular exocrine function in experimental animals.

Animals↗
PubMed1987

Partial ureteric obstruction: a new variable canine experimental model.

An experimental model of ureteric obstruction should be accurate and persistent, and allow variation of the degree of obstruction. A model was tested in 28 dogs consisting of insertion of an obstructing stent into the left ureter, and the degree of obstruction was varied by altering the internal diameter of the stents. The effects of such an obstruction on the following features were studied: renal intrapelvic pressure, intravenous urography, creatinine clearance, vascular casts, and both gross and histological examination. The procedure was well tolerated and caused a persistent, unchanging degree of partial ureteric obstruction. Pathological changes of obstructive uropathy were produced. This model can be used for further pathophysiological studies.

Animals↗
PubMed1985

Percutaneous coagulum nephrolithotripsy: a new approach.

Intrarenal scatter of stone fragments during percutaneous nephrolithotripsy is a complication which may predispose to post-operative pain and further stone formation. The use of a coagulum to prevent such a complication has proved difficult when introduced percutaneously. This experimental study describes a new gelatine (Lithogel) which is introduced through the nephroscope to coat the renal calculus; it allows easy disintegration of the calculus within the gel, is safe to use and effectively prevents the scatter of fragments into inaccessible calices.

Animals↗
PubMed1984

The pulpal response to citric acid in cats.

Citric acid conditioning of dentine has been proposed as an efficacious treatment for promoting re-attachment after periodontal surgery. This study investigated the pulpal reactions to periodontal surgery combined with citric acid (pH 1) demineralization of exposed dentine for 3 min. 9 cats were used as the experimental animals, with each cat providing 1 negative and 1 positive control and 2 experimental canine teeth. Evaluation was over 3 observation periods, with 3 cats in each period being sacrificed at 4, 21 and 83 days. Positive control teeth, which underwent periodontal surgery combining the removal of approximately 3 mm2 of labial bone and vigorous root planning of the exposed root surfaces, displayed mild to moderate pulpal reactions during the short- and intermediate-term periods and only mild to no reactions in the long-term period. The addition of citric acid demineralization, however, resulted in 5 experimental teeth (28%) becoming abscessed or totally necrotic in the intermediate- and long-term periods. At 21 days, the frequency of adverse pulpal responses to surgery and citric acid conditioning was significantly (p less than 0.05) greater than to surgery alone. Although 4 experimental teeth were relatively uninflamed at the long-term period of observation, all showed irritational dentine formation. Penetration of exposed dentinal tubules by plaque bacteria was observed only in the citric acid treated teeth.

Acid Etching, Dental↗
PubMedDate not supplied

Inflammatory aortic aneurysm: report of a case suggesting athero-ischaemic aetiology.

A case of inflammatory aortic aneurysm is presented in which histology revealed athero-emboli in the aortic vasa vasorum. It is suggested that ischaemic injury to the media, caused by lesions such as these and by other features of atherosclerosis, may be the initiating factor in some cases of idiopathic chronic periaortitis.

Aged↗