Release of cortical catecholamines by visual stimulation requires activity in thalamocortical afferents of monkey and cat

Catecholamine (CA) release was measured in vivo in the monkey and cat visual cortices electrochemically. Stereate-modified, graphite-paste electrodes were used to monitor changes in norepinephrine and dopamine release. Micromolar changes in CA concentration were obtained by stimulation of the eye with nonspecific (strobe) or specific (oriented bars, radial gratings) stimuli. CA release depended on which eye was illuminated. Electrodes passed tangentially through the striate area recorded release following visual stimulation of one eye or the other in succession, and the shift in eye dominance occurred at about 500 microns intervals. The magnitude of CA release was highly correlated with the ocular dominance of neuronal activity measured with tungsten microelectrodes. Light-stimulated release was not recorded in monkey area V2, V4, or somatosensory area 1, but was recorded in cat V2, suggesting that the presence of LGN afferents is associated with CA release. Results are discussed in terms of the role of geniculate activity and the specific role of CAs in cortical information processing.     

Failure of ivalon to provide permanent hepatic arterial occlusion

Ivalon (polyvinyl alcohol) is a commonly used embolic agent, generally considered to be permanent. In a patient with the carcinoid syndrome, embolization of hepatic metastases with Ivalon failed to produce permanent occlusion, and recurrent tumor was supplied by many of the same small arteries identified on the original arteriogram. Occasionally, Ivalon may have only a temporary occlusive effect. A possible explanation for this phenomenon is proposed.     

Hernia through the foramen of Winslow: a complication of cholecystectomy. A case report

In 151 years since first described, there have been 112 reported cases of hernia through the foramen of Winslow (HFW). All thus far have described HFW as a primary entity. The case reported appears to be unique with HFW as a surgical complication. HFW is the least common of internal hernias. The primary symptom is pain referred from the herniated organ and the hepatoduodenal ligament. An interesting sign is that the patient is found curled up or stooped over for pain relief. Anatomic factors implicated in HFW are an enlarged epiploic foramen, a floppy cecum and ascending colon, or abnormal length of small bowel mesentery. Tension on these structures causes pain with the torso extended. Distention of bowel in the lesser sac mimics gastric obstruction. Organs herniated are: small bowel (63%); cecum, ascending colon, and terminal ileum (30%); and transverse colon (7%). Of 25 cases reported since 1966, cecal herniation comprised two-thirds. The diagnosis may be made radiologically and the treatment is surgical. The case and a review of the literature are presented with attention to the anatomy. Also provided are the signs and symptoms of this interesting and perplexing diagnosis.     

Acute ureteral colic from an obstructing renal aspergilloma

Fungus balls of the renal collecting system are rarely of organisms other than Candida. A case of obstructing aspergilloma associated with acute ureteral colic is presented. The clinical features of this case are characteristic of renal aspergillomas in 10 additional cases described in the literature. Ten of the 11 patients were male. Each of the patients had an underlying disease that predisposed to fungal infection. Although all 11 patients were cured, diagnostic evaluation was often protracted as commoner causes of ureteral obstruction were excluded. Successful therapy required evacuation of the obstructing hyphal mass; open surgical procedures were necessary in five instances. Systemic amphotericin B should be reserved for patients with residual infection following removal of the fungus ball. This report emphasizes the need to consider aspergilloma in the differential diagnosis of acute ureteropelvic obstruction in the appropriate patient population.     

Changes in axonally transported proteins in the mature and developing rat nervous system during early stages of methyl mercury exposure

It was established by means of SDS polyacrylamide gel electrophoresis that direct injections of methyl mercury (10 micrograms Hg) into the mature rat vitreous body of the eye decrease protein synthesis in the retina and optic nerve at 4 hours after injection. Although the global spectrum of polypeptides did not change, a specific decrease in the volume of polypeptides of 20-23 K daltons molecular weight was evident. Conversely, systemic exposure to methyl mercury resulted in increased protein synthesis of polypeptides of 20-23 K molecular weight both in adult (8 mgHg/kg/day for 8 days) and neonatal rats (2 mgHg/kg/day for 10 days). In addition, specific changes in the volume of polypeptides 75-90 K molecular weight were noted in sciatic nerves of neonatal rats. These data are consistent with a bimodal response in protein synthesis following MeHg treatment. Local presence of MeHg following direct injection into the eye causes a reduction in protein synthesis, while chronic systemic exposure results in increased synthesis and transport of proteins in both mature and developing optic nerves and neonatal sciatic nerves. Thus, these systems possess the capacity to attempt regenerative processes through induction of a small subset of proteins known as GAPs (Growth-Associated Proteins) during the early stages of systemic methyl mercury exposure. These wide spread and system-specific changes are consistent with growth-specific functions during the early stages of methyl mercury exposure.     

The mechanism of action of tumor necrosis factor (TNF) on tumor vascularity--study using a transparent chamber

Effects of human recombinant TNF on the tumor blood vessels and on the thrombus formation were investigated in relation to its mode of antitumor action against Meth-A sarcoma transplanted in BALB/c mice. The extent of the blood vessel lesion was evaluated by using transparent chamber placed in the mouse skin. Bleeding, hyperemia and congestion were observed at 1-2h, 4-6h and 24h after TNF (1 X 10(4)U/mouse) administration, respectively. In contrast, no histological changes in the normal blood vessels were observed microscopically following TNF injection. Thrombus formation was evoked in the tumor vessels 4h after TNF injection. However, when thrombus formation was prevented by heparin, no difference was observed among antitumor action of TNF against Meth-A fibrosarcoma necrotic response and the rate of complete cure. These results suggest that the direct effects of TNF causing lesions in the tumor blood vessels plays an important role in its antitumor action.