Antiphospholipid antibodies and pregnancy rates and outcome in in vitro fertilization patients.

OBJECTIVE: To determine the relationship between antiphospholipid antibodies and pregnancy rates (PRs) and outcome among IVF patients. DESIGN: Prospective collection of all serum samples with assays for immunoglobulin G (IgG), IgA, and IgM antibodies for anticardiolipin, antiphosphatidyl serine, antiphosphatidyl ethanolamine, antiphosphatidyl choline, antiphosphatidyl inositol, antiphosphatidyl glycerol, and antiphosphatidic acid being done following completion of all treatment cycles. SETTING: A tertiary care teaching hospital. PATIENT(S): Seven hundred ninety-three patients attempting to conceive through IVF. MAIN OUTCOME MEASURE(S): Pregnancy rates (PRs) and pregnancy loss rates relative to each of the various antiphospholipid antibodies that were measured. RESULT(S): There were 528 pregnancies for an overall PR of 66%. Pregnancy rates were equal among patients with positive and negative antiphospholipid antibodies for each of the 21 measured antibodies. Use of receiver operator characteristic curves and logistic regression further confirmed that there was no relationship between PRs or outcome based on antiphospholipid antibodies for any definable threshold value. CONCLUSION(S): Elevated antiphospholipid antibody levels are not associated with any change in PRs or pregnancy loss rates in patients attempting to conceive through IVF.

Elevated SGOT/SGPT ratio in alcoholic patients with acetaminophen hepatotoxicity.

Two alcoholic patients with acetaminophen hepatotoxicity are described. Both patients had very high SGOT levels and SGOT/SGPT ratios. It is suggested that a high SGOT/SGPT ratio is not specific for alcoholic hepatitis. Extreme elevations of this ratio, especially in association with SGOT levels greater than five times normal, should suggest nonalcoholic causes of hepatocellular necrosis in alcoholic patients.

Alterations in hepatic pericanalicular cytoplasm during enhanced bile secretory activity.

In an attempt to demonstrate the morphology of the bile secretory apparatus, male rats were restrained and maintained on an isocaloric diet with (experimental) and without (control) taurocholate, which was continuously infused via a duodenal cannula. This method of taurocholate administration promotes a 2-fold increase in the bile acid pool size and bile secretory rate and increases the transport maximum of taurocholate by approximately 50%. After 48 hours, the livers from both the control and experimental animals were perfusion-fixed and whole hepatocytes as well as pericanalicular cytoplasm (defined as a 1-micron. wide zone of cytoplasm adjacent to the bile canaliculus) in both centrolobular and periportal cells were subjected to a stereologic analysis. Although taurocholate infusion produced relatively few changes in the amounts of organelles or inclusionswithin hepatocytes, it caused highly significant increases in the amount ofGolgi-rich area, Golgi membranes, and the number of vesicles with diameters greater than 1000 A in the pericanalicular area of cytoplasm. In addition to these changes, which occurred in both central and periportal zones, decreases in the volume of lysosomes and the surface area of smooth surfaced endoplasmic reticulum were observed. These data provide new evidence that the "bile secretory apparatus" may encompass several hepatocellular components which include the Golgi complex and a vesicular transport system.

A quantitative analysis of hepatic ultrastructure in rats during enhanced bile secretion.

The ultrastructural changes in hepatocytes of rats subjected to selective biliary obstruction (SBO), wherein the biliary system draining approximately two-thirds of the liver is obstructed, were evaluated by quantitative electron microscopy or stereology. The remaining unobstructed portion of the organ compensates for this loss of bile secretion by functioning in a hypersecretory mode. This animal model permits the comparison of hepatocellular fine structure associated with the conditions of nonsecretion and hypersecretion of bile with that found in normal secreting sham-operated rats. Since recent evidence suggests the presence of lobular gradients in hepatic structure and function, both centrolobular and periportal hepatocytes were examined. The low incidence of Golgi membrane profiles in high magnification electron micrographs results in a low confidence level of sampling and, thus, necessitates the application of a novel parameter for estimating the amount of Golgi complex, i.e., the Golgi-rich area. For the most part, the lobular variation in hepatic fine structure in the sham-operated animals was similar to that described by Loud ('68). However, the periportal parenchyma contained approximately twice the volume of Golgi-rich area as the centrolobular tissue. The amount of cytoplasmic lipid increased significantly in the SBO unobstructed lobes, although there were few or no changes in the other intracellular organelles or inclusions except those related to the Golgi complex. The volume of Golgi-rich area increased significantly in the centrolobular tissue of the SBO unobstructed (hypersecretory) lobes to the extent that both intralobular zones contained similar amounts of this component. These data suggest that the Golgi complex is a dynamic unit which responds to changes in hepatocellular activity and may be involved in bile secretion.

Sex differences in the size of bile acid pools.

In view of the excess prevalence of gallstones among women and the association of gallstones with diminished bile acid pool size, we measured bile acid pools in 27 male and 25 female healthy human volunteers. The average bile acid pool in the women was significantly smaller than in the men (2.25 +/- .12 g versus 2.88 +/- .16 g; p = 0.003). Chenodeoxycholic acid pool size, computed from bile acid composition data available in 43 of these subjects, was also smaller in women than men (0.94 +/- 0.06 versus 1.22 +/- 0.07 g; p = 0.004). Age, race, and body size bore no statistically significant relationship to bile acid pool size. Biliary cholesterol saturation was positively correlated with weight and obesity and showed a significant inverse correlation with chenodeoxycholic acid pool size, but not with total bile acid pool size. These findings suggest a possible mechanism for the higher prevalence of gallstones among women.

Bile acid-induced increase in bile acid-independent flow and plasma membrane NaK-ATPase activity in rat liver.

Previous studies showed that in rats with obstruction of the bile ducts draining the median and left hepatic lobes, and in rats with normal bile ducts in which the bile acid pool size and secretion were augmented by 48-h intraduodenal infusion of taurocholate, bile acid flux through secreting hepatocytes was increased. Under these conditions, taurocholate transport maximum exhibited a time-dependent adaptation to increased secretory load.Unexpectedly, bile acid-independent canalicular flow in these experimental models also was found to be increased when measured at 48 h. Relative to controls, bile acid-independent flow per gram of nonobstructed liver was increased approximately threefold in selectively obstructed rats and 43% in bile acid-loaded rats with normal ducts. In rats infused with bile acids at similar rates for only 16 h, no increase was observed. Studies with [(14)C]erythritol suggested that the increased bile flow under these conditions was of canalicular origin.NaK-ATPase activity in canaliculi-enriched liver plasma membrane preparations from the nonobstructed lobes of selectively obstructed rats and from 48-h bile acid-loaded rats was increased by 47% and 52%, respectively, relative to controls, but was not increased in membranes from 16-h bile acid-loaded rats. Canalicular membrane 5'-nucleotidase and Mg ATPase also were increased. These studies show that augmented bile acid flux through secreting liver causes an adaptive increase in bile acid-"independent" flow and in the activity of canalicular membrane enzymes. The mechanism by which bile acids modulate this and previously reported aspects of bile secretion remains to be elucidated.

Morphometric analysis of rat hepatocytes after total billary obstruction.

Using light and electron microscopic morphometric techniques, the effects of 48 hr of extrahepatic biliary obstruction on hepatocyte structure were examined in the rat. Liver cells near the portal area were compared to those in the centrilobular regions of the hepatic lobule. Observations on the normal animals confirm earlier evidence of quantitative differences in the surface density of organelles in hepatocytes located within different regions of the lobule. A striking difference in the quantity of the Golgi complex in the two areas of the lobule was noted for the first time, with the portal cells containing a significantly greater quantity of this organelle than centrolobular hepatocytes. After 48 hr of total obstruction, most of the previously reported qualitative changes in the canalicular and pericanalicular regions were confirmed. Morphometric analysis at the light-microscopic level showed an increase in the number of cells and a decrease in cell size in those cells near the portal area were compared to those in the centrolobular regions of the helar level demonstrated a significant decrease in both rough and smooth surfaced endoplasmic reticulum in cells of both zones, a finding in marked contrast to the hypertrophy of smooth endoplasmic reticulum suggested by other investigators on the basis of qualitative assessments. There was also a striking decrease in the amount of the Golgi complex, limited to cells in the portal regions. In addition, in all zones a decrease in the volume density of mitochondria and lysosomes was noted, whereas the volume of microbodies was increased. It is suggested that this loss in total membrane material within the cell may be secondary to the degranulation and decrease in total surface area of rough surfaced endoplasmic reticulum, an organelle thought to be responsible in part for the synthesis of new cellular membranes. These observations suggest that present concepts concerning the pathogenesis of cholestatic liver disease require reappraisal.

Determination of bile acid pool size in man: a simplified method with advantages of increases precision, shortened analysis time, and decreased isotope exposure.

A simplified isotope dilution method for measurement of the bile acid pool size in normal subjects is described and compared with the traditional method of Lindstedt (Acta Physiol. Scand. 40: 1-9, 1957). Advantages of this simplified method include a four- to eightfold reduction of isotope dose, facilitation of analytical procedures, and a reduction in the required number of duodenal intubations. In 15 human subjects who had two separate estimates of pool size by this method, precision averaged 2.6 percent. In 16 comparisons, pool size measured by this method averaged 13.7 percent higher than simultaneous estimates by the Lindstedt method. Factors affecting accuracy (as opposed to precision) in both methods are discussed.

Effects of low dose chenodeoxycholic acid feeding on biliary lipid metabolism.

To better define the mechanisms by which chenodeoxycholic acid (CDCA) alters the lipid composition of bile and promotes dissolution of cholesterol gallstones, we have studied the effects of relatively low doses of CDCA on the metabolism of biliary lipids in 10 subjects without gallstones. In 5 subjects, the effects of CDCA feeding were compared to those of cholic acid, a bile acid that apparently does not dissolve cholesterol stones. The following measurements were carried out during control and treatment periods: (1) composition of biliary lipids, (2) hepatic secretion rates of biliary lipids, (3) pool sizes of bile acids, and (4) specific composition of bile acids. Low doses of CDCA consistently reduced the lithogenicity of gallbladder bile by decreasing the proportion of cholesterol relative to the solubilizing lipids--bile acids and lecithin. This decrease in lithogenicity was associated with a selective reduction in hepatic secretion rates of cholesterol. At the doses of CDCA given, secretion rates of bile acids and lecithin and pool sizes of bile acids were not significantly changed; also conversion of cholesterol into bile acids was not completely inhibited. Cholic acid feeding appeared to increase the total size of the bile acid pool, but it did not affect the lithogenicity of bile or secretion rates of cholesterol. The data show that at low doses CDCA lowers lithogenicity of bile by reducing hepatic secretion of cholesterol, while cholic acid does not have a similar effect.

Mechanisms of lithogenic bile formation in American Indian women with cholesterol gallstones.

Hepatic secretions of biliary lipids were estimated in 43 patients with and without cholesterol gallstones. Studies were carried out by a marker dilution technique employing duodenal intubation with a three-lumen tube. Hourly secretion rates of cholesterol, bile acids, and phospholipids were determined during constant infusion with liquid formula. In 17 American Indian women with gallstones, hourly outputs of biliary bile acids were significantly less than those in 7 Indian men and 12 Caucasian women without gallstones. These findings suggest that a decreased hepatic secretion of bile acids contributes significantly to the production of a lithogenic bile in Indian women. However, in Indian women with gallstones, secretion of biliary cholesterol was also significantly increased, as compared with Caucasian women without stones. Therefore, lithogenic bile in Indian women was, in most cases, due to a combined decrease in bile acid output and increase in cholesterol secretion. In an attempt to determine the mechanisms for these abnormalities, cholesterol balance studies were done in Indian women with gallstones and normal Indian men. Balance data were compared with results reported previously in non-Indian patients studied by the same techniques, and in general, Indian women showed a slight increase in fecal excretion of bile acids. Since bile acids in the enterohepatic circulation were relatively depleted in Indian women, these patients had a reduced fractional reabsorption. However, previous studies have shown that Caucasians can rapidly replenish bile acid pools in the presence of much greater intestinal losses, and it is suggested that among Indian women with gallstones, reduced secretion rates of bile acids are primarily the result of defective homeostatic regulation of bile acid synthesis. In Indian women with gallstones, at least two factors may have contributed to an increased availability of cholesterol in the liver for secretion into bile. First, cholesterol was inadequately converted into bile acids, and secondly, an increased amount of cholesterol was synthesized, as shown by the balance technique. This enhanced production of cholesterol can partially be explained by obesity, but other factors may also play a role.