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Biomedical subjects

D LaFontaine

Publications and source records attributed to D LaFontaine.

5 recordsLinked to original sources

Management of massive ovarian tumors.

Two patients with massive ovarian tumors, one with a 51 kilogram Stage IC mucinous cystadenocarcinoma and the other with a 34 kilogram mucinous cystadenoma, are presented. Problems associated with resection of massive ovarian tumors, including respiratory failure, intraoperative fluid shifts, adequate exposure, orthostatic hypotension and adynamic intestine, are identified. Guidelines for avoiding these pitfalls by the use of appropriate monitoring, controlled drainage of the cyst and transverse elliptic incision with abdominoplasty are suggested.

Abdominal Muscles↗

Hepatic failure toxins depress liver regenerative enzymes after periportal injury with allyl alcohol in the rat.

Hepatic regenerative enzyme (thymidine kinase and ornithine decarboxylase) activities were significantly depressed by subcoma doses of the hepatic failure toxins (NH4+, octanoic acid, and dimethyl disulfide) after selective injury with allyl alcohol. The inhibitory effect of NH4+ was greater than that of dimethyl disulfide, even though the neurologic effects of dimethyl disulfide were approximately comparable with those of the NH4+. There appeared to be a delay in the full expression of the depressive effects of octanoic acid and dimethyl disulfide. The resistance to these two toxins, particularly dimethyl disulfide, may reflect the resistance to injury of the oxidative processes prominent in periportal hepatocyte mitochondria. In comparison with pericentral injury or two-lobe hepatectomy, periportal injury seemed equally susceptible to regenerative enzyme inhibition by NH4+ but less susceptible to the effect of octanoic acid and dimethyl disulfide.

Ammonia↗

Effect of hepatic failure toxins on liver thymidine kinase activity and ornithine decarboxylase activity after massive necrosis with acetaminophen in the rat.

After massive liver injury with acetaminophen, subcoma doses of hepatic failure toxins (NH+4, dimethyl disulfide [----methanethiol], octanoic acid) depressed liver thymidine kinase (TK) activity by 78%, 85%, and 90%, respectively, and ornithine decarboxylase (ODC) activity by 40%, 83%, and 78%, respectively. Twenty-four hours after the last dose of the toxins the depressant effects were still evident. The doses of dimethyl disulfide and octanoic acid required for these depressant effects on TK activity were less than half those required for similar effects previously reported after two-lobe hepatectomy of normal rat liver. The dose of NH+4 required was not reduced. None of the toxins depressed ODC activity after the hepatectomy, in contrast to their depressant effects after acetaminophen. Thus doses of the hepatic failure toxins that were about one fourth to one half those needed to induce coma in normal rats inhibited activity of regenerative enzymes after acute massive liver injury with acetaminophen. The effects were persistent for at least 24 hours. These observations may have relevance to the lack of regeneration observed commonly after fulminant hepatic failure in humans.

Acetaminophen↗

In vivo studies of GABAergic effects in experimental hepatic encephalopathy.

The GABAergic agonist, muscimol, and antagonists, picrotoxin and bicuculline, have been studied in rats with chronic portacaval shunts and in rats developing hepatic encephalopathy after massive ischemic necrosis due to hepatic artery ligation within 48 hr of a portacaval shunt. After the chronic portacaval shunt and to a lesser extent in normal rats intraventricular muscimol resulted in chewing and eating behavior, ataxia and loss of balance that lasted 2 to 3 hr. Lethargy, stupor and coma did not occur. Intraventricular saline had no effect. Bicuculline i.p. lessened the effects of the muscimol. In rats developing hepatic encephalopathy, intraventricular muscimol shortened the time to precoma and coma by approximately 40%. Bicuculline i.p. counteracted this effect of muscimol significantly. However, neither bicuculline nor picrotoxin given alone altered the times to precoma (Stage III), coma (Stage IV) or death. While hepatic encephalopathy in this experimental model is susceptible to GABAergic effects, its natural progression does not appear to be due to GABA.

Animals↗