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Biomedical subjects

I S Johnsrude

Publications and source records attributed to I S Johnsrude.

At least 19 recordsLinked to original sources
PubMed1994

Effect of motivational context on conspecific song discrimination by brown-headed cowbirds (Molothrus ater).

Two experiments to examine the effects of motivational context on the perception of conspecific song by cowbirds were conducted. In the first experiment, sexual displays were elicited from females by playback of normal song and rearranged sequences of the component phrases. In a second experiment, male and female cowbirds discriminated among the same songs in a food-rewarded operant procedure. In a sexual context, the birds were sensitive to both the beginning and end phrases of normal song, whereas in a food context, the birds were more sensitive to the beginning of normal song. In both experiments, one-phase songs were better discriminated from normal song than two-phrase songs, and there was no effect of phrase order on discrimination. Similarities and differences in the results of the two experiments suggest that some aspects of cowbird song perception remain constant across motivational contexts, whereas others are unique to particular motivational contexts.

Acoustic Stimulation↗
PubMed1994

Percutaneous transluminal angioplasty for subclavian artery stenosis.

Treatment of brachiocephalic arterial lesions by percutaneous transluminal angioplasty (PTA) has only recently been performed with sufficient frequency to allow full assessment of its value. In this series, we report our results with PTA of 36 symptomatic subclavian stenoses in 33 patients seen from February 1981 through February 1992. Initial success rate was 94 per cent. There were no deaths and no CNS complications. Five minor complications occurred. Review of published surgical series suggests a similar early success rate but a significantly higher morbidity. These excellent early results of PTA and long-term results from other studies confirm that PTA of subclavian artery stenoses is a safe, highly effective procedure and should be considered the treatment of choice for symptomatic subclavian artery stenoses.

Adult↗
PubMed1989

Transrenal ureteral occlusion with Gianturco coils and gelatin sponge.

The authors report the use of Gianturco coils and gelatin sponge plugs to achieve complete occlusion of nine ureters in five patients with advanced pelvic malignancies and lower urinary tract fistulas. The method is simple to apply, is readily available, and to date has been associated with no significant complications. These results suggest that, before more elaborate methods of ureteral occlusion are applied, the use of coils and gelatin sponge should be considered as the primary method of ureteral occlusion. Further work is needed to elaborate the exact mechanism by which these materials cause occlusion.

Embolization, Therapeutic↗
PubMed1989

Split 24-F Amplatz dilator for percutaneous extraction of an intravascular bullet: case report and technical note.

An intravascular bullet was retrieved percutaneously in a 17-year-old boy with the use of a modified 24-F Amplatz dilator. The dilator was modified by means of a longitudinal incision with removal of a wedge at the distal tip of the tapered portion of the dilator. The bullet, which was located in the left pulmonary artery, was removed via the right femoral vein. No complications occurred.

Adolescent↗
PubMed1988

The bird's nest inferior vena cava filter: progress report.

The bird's nest inferior vena cava filter, in clinical trial since 1982, has been placed in 568 patients at risk for pulmonary embolism. Of the 481 patients in whom the filter had been in place for 6 months or more, 440 were followed up clinically. The prevalence of clinically suspected recurrent pulmonary thromboembolism was 2.7% (12 patients) and that of inferior vena cava filter occlusion was 2.9% (13 patients). With the initial filter design, filter migration occurred in five patients. No migrations have occurred in the 147 patients treated with the filter after its modification to improve the anchoring system for greater stability. The bird's nest filter has proved safe and effective in the prevention of pulmonary embolism.

Clinical Trials as Topic↗
PubMed1985

Percutaneous catheter balloons: failure to deflate.

Three examples of permanently inflated transluminal catheter balloons are presented. Two of these occurred during attempted percutaneous transluminal angioplasty. Nonsurgical solutions, which were successful in each case, are described. Percutaneous puncture with a needle or a larger diameter coaxial catheter under fluoroscopic guidance may be useful when this complication occurs during attempted balloon angioplasty or embolization with proximal balloon occlusion in large vessels.

Aged↗
PubMed1982

Thyroid venous catheterization in the early diagnosis of familial medullary thyroid carcinoma.

In kindreds with familial medullary thyroid carcinoma (MTC), individuals are often detected whose peripheral plasma calcitonin (CT) levels are undetectable in the basal state but increase minimally following provocative testing. The proper management of such patients has been uncertain, but most investigators have advocated repeat testing and evaluation after an interval of several months. The present study was conducted to evaluate the diagnostic implications of these modest increases in plasma calcitonin. In 25 kindred members at direct risk for familial medullary thyroid carcinoma (MTC), basal peripheral plasma calcitonin (CT) levels were less than 240 pg/ml. Following provocative testing with intravenous calcium or pentagastrin or both, calcitonin values remained below 240 pg/ml in eight subjects (Group A), however, they were mildly elevated (260-580 pg/ml) in 12 subjects (Group B) and moderately elevated (700-940 pg/ml) in five subjects (Group C). Following the transfemoral placement of a catheter into the inferior thyroid vein (ITV), provocative testing was repeated, and ITV and peripheral blood samples were collected simultaneously. Basal ITV plasma CT levels were below 240 pg/ml in all patients in Group A, however, they were mildly elevated (500 pg/ml) in one of the 12 patients in Group B and moderately elevated (800 pg/ml, 1400 pg/ml) in two of the five patients in Group C. Following provocation, ITV plasma CT levels became markedly elevated in one patient in Group A and in all of the patients in Groups B(2520+/-635 pg/ml) and C (6322+/-2598 pg/ml). Thyroidectomy was performed in patients whose ITV plasma CT level was elevated following provocative testing. Medullary thyroid carcinoma of C-cell hyperplasia were evident either on microscopic (1/1 patient in Group A;9/12 patients in Group B; and 2/5 patients in Group C), or gross (3/12 patients in Group B;3/5 patients in Group C) examination of thyroidectomy specimens. In only one of 14 patients was metastatic MTC noted on histologic examination of resected cervical lymph nodes. Postoperative peripheral plasma CT levels were unchanged from basal and less than 240 pg/ml following provocative testing in all but one patient. The present study then provides definitive evidence that patients at direct risk for familial MTC who have even minimally abnormal responses in peripheral plasma CT following provocative testing generally harbor some stage of a C-cell proliferative disorder. Identification of such individuals with early disease is important because thyroidectomy offers an extremely high cure rate.

Adolescent↗
PubMed1980

Vessel occlusion with transcatheter electrocoagulation.

Transcatheter intravascular electrocoagulation for therapeutic occlusion of vessels has been experimentally developed and successfully used clinically as an alternative to, and in conjunction with, more routine methods of vessel occlusion. A constant current power source and a steelguide wire anode are used for the occlusion. The subject is grounded with a standard bovie plate insulated from the skin by a highly lubricated sponge. Permanent occlusion of strategic vessels at accurately controlled sites has been achieved with little risk of embolization of non-target areas. There has been minimal damage to vessel walls, and complete occlusion has been possible despite heparinization and/or thrombocytopenia. One limitation is the inconstant ability to position the anode precisely at the desired site of occlusion. Also, a long time may be required (up to one hour) to occlude larger vessels with presently available anodes. Wider use must await refinements in development of the anode material and in its delivery system.

Arteriovenous Fistula↗
PubMed1980

Epidural anesthesia in aortofemoral arteriography.

The experience with a well-established regional anesthetic technique i.e., epidural anesthesia for alleviating pain during aortofemoral arteriogrpahy is described. Of 59 patients, 51 experienced no subjective or objective evidence of pain, while eight patients subjectively reported mild burning pain during injection of contrast. Apart from patient satisfaction, important additional benefits of epidural anesthesia were excellent filling of both distal small arteries and collateral vessels around obstructing arterial lesions. Complications were few and insignificant. It is concluded that epidural anesthesia is a safe procedure that not only eliminates pain, but also gives better quality radiographs.

Adult↗
PubMed1980

Acute gastrointestinal hemorrhage of small-bowel origin.

Of 305 patients with acute gastrointestinal (GI) bleeding, the site was found to be the small bowel in 16. In all cases the cause was proved at surgery or autopsy: diagnoses included vascular malformation, aorto-enteric fistula, primary or metastatic tumor, ulcer, tuberculous ileitis, and sarcoidosis. While it is uncommon for acute GI bleeding to originate in the small bowel, approximately one third of the patients with acute rectal bleeding in this series had a bleeding site in the small bowel.

Adult↗
PubMed1979

Arteriographic embolization for control of recurrent severe gastric hemorrhage in a 10-yr-old boy.

Severe stress ulceration or stress gastritis may occasionally produce uncontrollable gastric hemorrhage in the pediatric age group. Modern arteriographic techniques utilizing selective embolization to occlude demonstrated bleeding arteries can successfully control such hemorrhage and avoid emergency destructive surgical resection. A 10-yr-old boy, in whom a previous 80% gastric resection failed to control life threatening hemorrhage, is presented, with roentgenographic demonstration of the procedure and the successful control of his gastric bleeding.

Angiography↗
PubMed1979

Vessel occlusion with transcatheter electrocoagulation: initial clinical experience.

Transcatheter electrocoagulation (TCEC) was used for vessel occlusion in combination with embolization by Gelfoam and/or Ivalon in six patients in whom other interventional or surgical techniques were considered dangerous or unfeasible. The technique was effective in decreasing or obliterating the blood supply to variously located lesions in all cases. The only complications were small skin burns in one patient and a small ulceration of the upper lip in another.

Adult↗