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Biomedical subjects

W E Lightfoote

Publications and source records attributed to W E Lightfoote.

8 recordsLinked to original sources
PubMed1979

New ultrastructural evidence for a protein transport system in endothelial cells of gerbil brains.

Pathways for transfer of horseradish peroxidase (HRP) across the cerebral microvasculature were studied in Mongolian gerbils after inducing either unilateral carotid-artery ligation or intracarotid air embolism. Electron microscopy on samples from both ipsilateral and contralateral brain hemispheres showed the reaction product (HRP) in the endothelial cytoplasm of capillaries and arteriols in all animals; in the basal lamina, HRP was seen only after long (3--4 h) ischemic periods. HRP was seen within both spherical and tubular structures, with the latter appearing in obliquely or longitudinally sectioned blood vessels. These endothelial channel-like structures are part of a tubulovesicular network which seemingly exists in the normal endothelium of the gerbil brain. The tubules serve as pathways for proteins into the brain; protein transfer becomes enhanced following circulatory injuries such as ischemia.

Animals↗
PubMed1979

Cerebral abscesses produced by bacterial implantation and septic embolisation in primates.

The degree of brain abscess encapsulation is positively related to surgical mortality and methods to enhance capsule wall formation, therefore, have therapeutic relevance. Two primate models are described which may be useful in the investigation of encapsulation of traumatic and metastatic brain abscesses. Direct intracerebral inoculation induces abscesses displaying more prominent inflammatory responses and encapsulation than does septic embolisation, despite similar abscess age and size. Cerebral ischaemia surrounding metastatic suppurative foci may retard capsule wall formation.

Animals↗
PubMed1978

Role of vascular proliferation on angiographic appearance and encapsulation of experimental traumatic and metastatic brain abscesses.

Experimental traumatic abscesses were produced in rhesus monkeys by intracerebral injection of nutrient agar contaminated with Staphylococcus epidermidis, and metastatic abscesses were induced by intracarotid embolization of silicone cylinders contaminated with Staphylococcus epidermidis. All monkeys underwent preoperative and serial postoperative carotid angiography. Traumatic abscesses produced early capsular blushes and progressive anterior cerebral artery displacements. Metastatic abscesses induced transient midline shifts but no capsular stains. Postmortem studies on the monkeys showed that mean capsular thickness and segmental wall vascularity of the traumatic and metastatic abscesses were significantly different (p less than 0.001), despite equal abscess ages and similar abscess volumes. In comparison to traumatic abscesses, metastatic abscesses demonstrated reduced inflammatory cell infiltration and retarded collagen formation around proliferating capsular vessels. Brain surrounding the metastatic abscesses demonstrated ischemic changes. The results suggest that 1) capsular blushes during cerebral angiography are secondary to vascular proliferation within the capsule and not to compression of surrounding brain, 2) vascular staining reflects capsular thickness, 3) capsular vascularity contributes to collagen formation, 4) encapsulation is dependent upon the integrity of surrounding brain, and 5) adjacent cerebral ischemia may impede inflammatory responses involved in capsule formation.

Animals↗
PubMed1978

Comparison of ketamine and pentobarbital anesthesia in the Mongolian gerbil.

The clinical course of pentobarbital and ketamine anesthesia are compared following a single injection of each and as anesthesia for carotid ligation in the Mongolian gerbil. Induction time to pinprick insensitivity was found to be the same for each agent; however, ketamine allowed earlier emergence and, moreover, observation of peripheral motor activity during the operative procedure.

Anesthesia↗
PubMed1975

Continuous vertical pendular eye movements after brain-stem hemorrhage.

Electro-oculographic studies are reported in a 33-year-old man with bilateral horizontal gaze palsies and continuous pendular eye movements in the vertical plane secondary to hemorrhage from a pontine arteriovenous malformation. The effects of pharmacologic and physiologic stimuli on the movements are described.

Adult↗
PubMedDate not supplied

Modification of cerebral ischemic damage by anesthetics.

The yield of infarcted hemispheres following unilateral carotid ligation in gerbils under ketamine anesthesia substantially exceeded that occurring under pentobarbital anesthesia. In addition to increasing the gerbil stroke model's efficiency, ketamine provided a shorter recovery period, thus allowing earlier observation of clinical signs of brain injury. These results support the contention that anesthetic agents may modify the response of central neuronal tissues to acute ischemia.

Anesthetics↗