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Biomedical subjects

J T Robertson

Publications and source records attributed to J T Robertson.

At least 127 records · Page 7Linked to original sources
PubMed1985

Comparison of suture materials and suture patterns for inverting intestinal anastomosis of the jejunum in the horse.

In 7 horses, 4 anastomoses were done in the small intestine in each, using the combinations of synthetic absorbable monofilament and multifilament suture materials with continuous- and interrupted-suture patterns in the serosubmucosal layer of a 2-layer inverting-suture technique. Horses were evaluated 30 days after the operation for adhesion formation, lumen diameter, evidence of chronic obstruction, and suture tract inflammation at the anastomosis. Postoperative obstruction occurred in 5 of the 7 horses, and 6 horses survived. One horse was euthanatized on postoperative day 6 after 48 hours of ileus and obstruction; necropsy revealed a partial intussusception involving the anastomosis done with continuous multifilament-suture material. Two other horses that became obstructed between postoperative days 3 and 5 had protracted ileus and gastric reflux up to 48 hours' duration, but survived. Horses that had obstruction after the 6th postoperative day recovered within 4 hours of onset. The continuous inverting-suture pattern in the serosubmucosal layer resulted in significantly (P less than 0.05) fewer adhesions than did the interrupted pattern, and suture material had no effect on adhesion formation. There was no significant difference in the percentage of reduction of lumen diameter between the variations of the 2-layer technique, and there was no evidence of chronic obstruction related to any of the anastomoses. Suture tract inflammation was moderate in the anastomoses, using continuous-multifilament suture, with neutrophils being the predominant cell type. The anastomoses with continuous-monofilament suture had mild inflammation with focal accumulations of neutrophils. Minimal inflammation was associated with both types of suture in the interrupted pattern.

Animals↗
PubMed1985

Visceral analgesia: effects of xylazine, butorphanol, meperidine, and pentazocine in horses.

The visceral analgesic, cardiorespiratory, and behavioral effects induced by xylazine, butorphanol, meperidine, and pentazocine were determined in 9 adult horses with colic. Colic was produced by inflating a balloon in the horses' cecum. Heart rate, respiratory rate, mean arterial blood pressure, and cardiac output increased after cecal balloon inflation. Xylazine and butorphanol decreased the hemodynamic response to cecal balloon inflation. Meperidine and pentazocine had minimal effects on the cardiorespiratory changes induced by cecal balloon inflation. Xylazine produced the most pronounced visceral analgesia. The duration of visceral analgesia was longest with xylazine (approx 90 minutes) followed by butorphanol (approx 60 min) and then by meperidine and pentazocine (approx 30 to 35 min). Accurate assessment of the effects of visceral analgesics is dependent upon the use of objective tests to evaluate pain.

Analgesia↗
PubMed1984

Comparison of responses elicited by alpha-thrombin in isolated canine basilar, coronary, mesenteric, and renal arteries.

Alpha-thrombin was applied in cumulative concentrations of 0.001, 0.01, 0.1, 1.0, 10, and/or 100 U/ml to determine peak responses in isolated canine arterial rings. Alpha-thrombin failed to elicit contraction in the mesenteric artery, produced inconsistent effects in the renal artery, and produced biphasic effects (relaxation superseded by contraction) in the coronary and basilar arteries. In the basilar artery the relaxation induced by alpha-thrombin was blocked and the maximal contractions enhanced by reaming the vessel or by substituting heated thrombin for alpha-thrombin. The results support the hypotheses that alpha-thrombin acts on two distinct receptors in the basilar artery and that it is involved in the pathogenesis of cerebral vasospasm.

Amino Acid Chloromethyl Ketones↗
PubMed1984

Neurofibromatosis.

Explore the source record for details and available documents.

Genetic Counseling↗
PubMed1983

Current management of vertebral basilar occlusive disease.

The current medical and surgical management of vertebral basilar occlusive disease has been reviewed, with the emphasis on the lack of definitive data proving the absolute efficacy of one form of therapy. In addition, the renewed interest in medical and surgical therapy of the vertebral system has been displayed. More experience and detailed study should be directed towards the final solution of the best treatment for vertebral basilar insufficiency. The extracranial vascular procedure of choice for correcting a vertebral stenosis appears to be a vertebral to common carotid artery anastomosis. This therapy can be used for a subclavian steal syndrome, but the more established surgical therapy for a subclavian steal syndrome is a common carotid to subclavian bypass graft. The innovative microvascular techniques are too few in number of produce a definitive statement. However, the capability of these procedures has been well-demonstrated, and the patency rate is acceptable. On the other hand, these procedures are time consuming and, because they have been selected for patients who have failed in medical therapy, are tainted in that they are used with patients very difficult to manage successfully. With more aggressive diagnostic arteriographic study and renewed neurological interest in the vertebral basilar system, definite treatment regimens can be anticipated. Doubtless, the results of the extracranial-intracranial bypass study will have significant impact on our future approach.

Anticoagulants↗
PubMed1983

Ocular manifestations of pituitary adenomas.

Fifty patients with pituitary adenomas were evaluated preoperatively by an ophthalmologist; of these, 68% had visual field defects, the most common (25%) a superior bitemporal depression and 16%, bitemporal hemianopsia. Almost 60% of patients with field defects had visual complaints; 38% had visual acuity in one eye of 20/60 or less. Patients with larger, nonsecreting tumors had more visual defects than patients with secreting pituitary adenomas.

Adenoma↗
PubMed1983

Comparison of piroxicam, meclofenamate, ibuprofen, aspirin, and prostacyclin efficacy in a chronic model of cerebral vasospasm.

Previous studies have suggested that certain prostanoids are mediators of the pathological features of subarachnoid hemorrhage (SAH) and that a reduced synthesis of prostacyclin in the vessel wall might also contribute to the cerebral vasospasm associated with this malady. The present study was performed, therefore, to ascertain whether known inhibitors of prostanoid synthesis would negate the changes that accompany the intracisternal administration of 4 ml of autogenous arterial blood to dogs and whether prostacyclin would lyse the vasospasm that is present 24 hours after this intrathecal blood. Nonsteroidal anti-inflammatory drugs (NSAIDs) were given intravenously to anesthetized dogs 30 minutes before and again 3 hours after the intracisternal injection of blood. The induced cerebral vasospasm was studied arteriographically for 1 hour after the intrathecal blood and again on the following day. Behavioral recovery of the animals was also evaluated on the day after the simulated hemorrhage. The results show that, as a group, NSAIDs significantly (P less than 0.001) reduced the occurrence of vasospasm and behavioral change associated with intrathecal blood. However, piroxicam was more efficacious than meclofenamate, ibuprofen, or aspirin in preventing both the vascular and the behavioral changes observed. This efficacy may be due to the long half-life of piroxicam and to known and unknown pharmacological differences among these compounds. On the other hand, prostacyclin infused via the vertebral artery failed to affect the vasospasm present 24 hours after intrathecal blood. The findings suggest that a suitable NSAID could provide clinical protection from the deleterious consequences of SAH.

Animals↗
PubMed1983

Use of the carbon dioxide laser for acoustic tumor surgery.

The carbon dioxide laser has been used clinically in both otorhinolaryngology and neurological surgery for approximately 10 years. Only recently, however, have technical modifications allowed its use with the operating microscope, providing the increased precision and control necessary for intracranial surgery. This paper reports the authors' experience with the carbon dioxide laser in the removal of acoustic tumors, details the surgical technique involved, and describes the advantages that may accompany the use of the laser in the removal of these difficult lesions.

Cranial Nerve Neoplasms↗
PubMed1983

Comparisons of carmustine, procarbazine, and high-dose methylprednisolone as additions to surgery and radiotherapy for the treatment of malignant glioma.

Within 3 weeks of definitive surgery, 609 patients with histologically demonstrated, supratentorial malignant glioma were randomized to receive, in addition to 6000 rads of radiotherapy, one of four treatment regimens: carmustine (BCNU), high-dose methylprednisolone, procarbazine, or BCNU plus high-dose methylprednisolone. We analyzed the data for the total randomized population and for the 527 patients (87% with glioblastoma multiforme) in whom the initial protocol specifications were met (the valid study group). Significantly longer survival was experienced by patients receiving procarbazine or BCNU alone compared to those receiving only high-dose methylprednisolone. No other pairwise comparisons demonstrated differences significant at the 0.05 level. However, the combination of BCNU plus high-dose methylprednisolone tended to be less effective than BCNU alone in patients with poor prognosis. This study indicates that BCNU and procarbazine are moderately useful agents in conjunction with radiotherapy for patients with malignant glioma. In addition, future protocols may allow use of corticosteroids in conventional dosages for treating cerebral edema and controlling symptoms; conclusions based on survival as the endpoint are unlikely to be affected by administering steroids at somewhat greater than the usual dose. More effective regimens for the treatment of malignant glioma should be sought.

Adolescent↗
PubMed1983

A new analgesic drug combination in the horse.

A xylazine and butorphanol drug combination produced minimal and transient hemodynamic effects and no significant respiratory depression when administered to 6 healthy horses. Combining xylazine and butorphanol produced a synergistic analgesic effect and provided good chemical restraint for a standing surgical procedure.

Analgesia↗
PubMed1983

Carotid endarterectomy.

Carotid endarterectomy should be limited to selected patients who are good risks with definitive diagnostic criteria. The author discusses indications for carotid endarterectomy, postoperative management and timing, and operative technique.

Carotid Artery Diseases↗
PubMed1982

Effect of the calcium antagonist nimodipine on contractile responses of isolated canine basilar arteries induced by serotonin, prostaglandin F2 alpha, thrombin, and whole blood.

Nimodipine is a new calcium antagonist that has been advocated as a specific treatment for the cerebral vasospasm accompanying subarachnoid hemorrhage in humans because of reports that it selectively inhibits the constriction of cerebral arteries in vitro. Because calcium antagonists may have specific blocking actions, whereas the origin of vasospasm is likely to be multiplex, the effect of nimodipine on the contractions of isolated canine basilar arteries that are produced by serotonin, prostaglandin F2 alpha, thrombin, and whole blood was studied. The results demonstrate that nimodipine significantly inhibits the contractile responses induced by these diverse agonists whether it is given before or after the agonist. The findings suggest that, in canine cerebral arteries, a common calcium influx channel is involved in the responses elicited by a variety of receptor mechanisms and afford a rationale for the use of nimodipine in the treatment of the cerebral ischemia that often follows cerebral hemorrhage.

Animals↗