Biomedical subjects
R S Davis
Publications and source records attributed to R S Davis.
Release of sutured Penrose drain by optical urethrotome.
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Simplified new approach to endoscopic photography.
Information obtained by endoscopic examination can be shared with others by viewing sequentially through the same endoscope, "teaching attachments" allowing viewing ports through the same instrument, drawings based on the observers' recollection of the findings, and by endoscopic photography. Of these methods, endoscopic photography has the important advantages of speed and faithfulness of reproduction. Herein, we describe a simple technique for endoscopic color still-photography with illustrations of normal and pathologic findings.
Vasovasostomy: current state of the art.
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Penile fracture: operative management and cavernosography.
Three cases of acute penile injury are presented. Corpus cavernosography at the time of presentation was obtained, confirming the diagnosis. Radiologic evaluations including cavernosography and when indicated urethrography are discussed. Management modalities are reviewed including our preference for surgical exploration when a cavernosal tear has been documented.
Respiratory response to intraesophageal acid infusion in asthmatic children during sleep.
Nocturnal asthma has been associated with nighttime gastroesophageal reflux (GER). To establish whether the presence of acid in the lower esophagus causes bronchoconstriction, nine children with nocturnal asthma and GER underwent intraesophageal acid-infusion challenges during sleep. The patients were divided into two groups on the basis of presence or absence of a positive Bernstein test for esophagitis. The test was considered positive if acid infusion produced symptoms of heartburn. On two occasions, at approximately midnight and 4 to 5 A.M., 30 ml of normal saline was infused over 15 min into the distal esophagus followed by a similar infusion of 0.1N HCl. Respiration was continuously monitored by inductance plethysmography along with clinical evaluation. The saline and midnight acid infusions had no effect in either patient group; however, with the 4 to 5 A.M. acid infusion, all the patients with a positive Bernstein test developed significant changes in their respiratory pattern indicative of bronchoconstriction as well as overt clinical wheezing. In the patients with a negative Bernstein test, the 4 to 5 A.M. acid infusion had no effect. It is concluded that during sleep the presence of acid in the lower esophagus can trigger bronchoconstriction in asthmatic children with a positive Bernstein test and that these children appear to be more susceptible to the bronchoconstrictive effects of intraesophageal acid at 4 to 5 A.M. than at midnight.
Urachal abnormalities in the adult.
A spectrum of rare urachal abnormalities in the adult is described, including urachal cyst, infected urachal cyst and abscess, and urachal carcinoma. The clinical and radiographic features are presented, and diagnosis using ultrasound, computed tomography, and needle aspiration is discussed. Treatment of infected urachal cysts with percutaneous catheter drainage is described.
Stricture of ureter caused by stone basket manipulation.
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Postpuberal bilateral undescended testis.
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Soluble Brugia malayi microfilarial antigens protect mice against challenge by an antibody-dependent mechanism.
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Auriculotemporal syndrome in childhood.
Auriculotemporal syndrome, also known as Frey's syndrome, consists of the development of facial flushing or sweating over the distribution of the auriculotemporal nerve immediately following eating or drinking. It has been recognized in adults as a common postoperative complication of parotid-gland surgery or dorsal sympathectomy. The syndrome is uncommon in children. As its course is benign, it is important to recognize it, thus avoiding unnecessary referral and laboratory evaluation.
Ureteral injury associated with lumbar disk surgery.
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Evaluation of a patient with both aquagenic and cholinergic urticaria.
An 11-yr-old girl presented with a history of urticaria induced by warm or cool showers, exercise, and emotional stimuli. During evaluation she repeatedly developed generalized punctate urticaria, pruritus, palpitations, and headaches after warm baths or exercise, and she had a positive methacholine skin test. She developed similar lesions and pruritus after local application of sterile water, tap water, ethanol, normal saline, or 3% saline. The diagnosis of combined aquagenic and cholinergic urticaria was made and presented a unique opportunity to study and compare mediator release and clinical symptoms in both conditions. The patient was submerged in bath water at either 37 degree or 41 degree C to induce either aquagenic or cholinergic urticaria, respectively. Histamine was released into the systemic circulation in both conditions in a similar time course; however, systemic symptoms occurred only after the 41 degree C bath. After failure to induce tolerance to the 41 degree C bath water, hydroxyzine therapy was instituted. One week later she was rechallenged; few symptoms appeared, and a rise in serum histamine was not detected as had been shown in previous challenges. The data suggest that in our patient, hydroxyzine may have contributed to the inhibition of both histamine release and the appearance of symptoms during hot bath challenging.
Immunopathology of murine infection with Schistosoma mansoni: relationship of genetic background to hepatosplenic disease and modulation.
The influence of genetic factors on the manifestations of disease associated with infection with Schistosoma mansoni (portal hypertension, liver granulomas, hepatosplenomegaly) and their modulation were studied in inbred strains of mice. Three groups were identified according to the degree of portal hypertension: high (portal venous pressure, 19.1 cm H2O: DBA/1J), intermediate (8.9-13.4 cm H2O; BALB/cJ, DBA/2J, CBA/CaJ, C3H/HeJ, and BUB/BnJ), and low responders (6.1 cm H2O; C57BL/6J). Granuloma size, organomegaly, and portal venous pressure were strain dependent and not H-2 dependent and were determined by more than one gene. Studies of schistosomiasis in the F1 generation of high and low responders indicated that more than one gene is involved. Modulation of portal venous pressure between eight and 20 weeks of infection occurred in C57BL/6J but not in BALB/cJ mice and was transferable with immune lymphoid cells. These data indicate that disease associated with infection with S. mansoni and its modulation in mice are influenced by the genetic (non-H-2) background of the host and dependent in part on cell-mediated immunity.
Percutaneous antegrade extrusion of ureteral stones.
A technique to extrude small obstructing ureteral stones with a catheter through a percutaneous nephrostomy tract is described. The technique was successfully used to extrude obstructing ureteral stones in three patients who had ileal loop urinary diversions and who were poor operative risks, and in one patient who had had no previous urinary tract surgery. In these four patients, ureteral stones were dislodged and removed without complication. The technique may have advantages over previously described techniques, particularly in patients with ileal conduits in whom established retrograde cystoscopic techniques are difficult to perform, and in patients who are poor operative risks.
Use of labial tissue in repair of urethrovaginal fistula and injury.
Labial flaps were used during the delayed repair of urethrovaginal fistulas and during the immediate repair of an obstetric urethral injury. In two patients, the labial fat pad alone was used. In the third patient, the fat pad and the overlying labial mucosa were rotated to cover the urethral repair. Our favorable results suggest further use of labial tissue in the repair of urethrovaginal fistulas or urethral injury.
Echocardiogram in apical hypertrophic cardiomyopathy.
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The demonstration of vegetations by echocardiography in bacterial endocarditis. An indication for early surgical intervention.
The visualization of vegetations by M-mode echocardiography in patients with infective endocarditis has been suggested to imply a poor prognosis regarding the development of major systemic emboli, congestive heart failure and the need for early surgical intervention. The question of using the finding of vegetations by echocardiography as an indication for surgery is controversial. To answer this question, 30 patients with the clinical diagnosis of endocarditis were studied by echocardiography. In 17 of the 30 (57 per cent) vegetations were present (aortic eight, mitral four, both mitral and aortic five), whereas in 13 (43 per cent) no vegetations were visualized. Infecting organisms were similar in each group; Streptococcus viridans being the most common. The patients with echocardiographically demonstrable vegetations had a higher incidence of congestive heart failure compared to the patients without (14 of 17 versus six of 13, p less than 0.05), major emboli (eight of 17 versus two of 13, p = NS) and need for valve surgery (17 of 17 versus two of 13, p less than 0.001). Mortality was not significantly different in the two groups (six of 17 versus three of 13, p = NS). Urgent or emergency surgery was required in 16 of 17 patients with vegetations. Thus, the demonstration of vegetations by echocardiography identified a subset of patients with more severe disease in whom early operative intervention was required.