Grading written essays: a reliability study

The purpose of this study was to examine the interrater reliability of grades obtained by physical therapy and occupational therapy tutors in rating their students' term papers. This study was carried out in two phases. In phase 1, four student essay papers (two physical therapy students' papers and two occupational therapy students' papers) with grades that had been assigned from the previous year's course were randomly selected from a bank of papers. These papers were independently rated by three course planners (who were responsible for planning, coordinating, and tutoring in the course), and agreement as to the assignment of grades for each paper was established. In phase 2, the same students' essays were rated independently by eight course tutors. To test for differences among students' written essay papers and for differences among the raters in the subcategories of discipline (physical therapy versus occupational therapy) and level of expertise (novice versus experienced) in grading essays, a three-way analysis of variance was performed. An intraclass correlation coefficient (ICC) was calculated for interrater reliability. Although there were no statistically significant differences among the tutors with regard to their discipline and expertise, the reliability analysis produced an ICC of .79. Strategies to enhance the reliability of grading essays are discussed.

Export of intracellular HBsAg in chronic hepatitis B virus infection is related to viral replication

Serum and liver HBsAg bear an inverse relation to each other during the evolution of chronic hepatitis B virus infection and the quantity of HBsAg in tissue rises gradually with time. In this study, intracellular and extracellular levels of HBsAg were measured by radioimmunoassay in primary culture of hepatocytes from 30 patients with chronic hepatitis B virus infection to determine a possible relationship with hepatitis B virus replication. Serum levels of HBsAg correlated with markers of active viral replication (serum hepatitis B virus DNA, p less than 0.005, and tissue HBcAg, p less than 0.02) but inversely with tissue HBsAg (p less than 0.05). In similar fashion, in vitro export of HBsAg was also related to the presence of active viral replication markers (serum hepatitis B virus DNA, p less than 0.02, and tissue HBcAg, p less than 0.05) and negatively with tissue HBsAg (p less than 0.001). Export of HBeAg also correlated positively with markers of active viral replication (serum hepatitis B virus DNA, p less than 0.05 and tissue HBcAg, p less than 0.05). Further experiments indicated that intrahepatic pre-S1 and pre-S2 correlated closely with intrahepatic HBsAg, indicating that a failure to export HBsAg was unlikely to be attributable to deficient intracellular expression of pre-S1 or pre-S2. These data indicate that in vitro primary hepatocyte culture of hepatitis B virus-infected cells provides an accurate reflection of in vivo export of HBsAg and that this is closely related to the presence of active viral replication.

The relationship between recent cocaine use and pregnancy outcome

We conducted urine screening for cocaine metabolite in 500 consecutive women admitted to a labor and delivery unit. The pregnancy outcome of 411 of the women was determined at that admission. The prevalence of cocaine-positive urines was 15.3% (95% confidence interval 11.8-18.8%). A subset of this population that had not received prenatal care had a prevalence of 62% (95% confidence interval 47.2-76.6%). Women with positive urines were almost four times more likely to have preterm labor and over twice as likely to deliver a premature infant or one with a 1-minute Apgar score of 6 or lower. Our findings support the concept that urine drug screening for cocaine and/or other drugs of abuse should be considered in patients who present with no prenatal care, premature labor, premature delivery, and delivery of an infant with a 1-minute Apgar score of 6 or less. This strategy may enable us to identify and bring to therapy a population of women that could potentially go unrecognized.

Increased elastase-alpha 1-antitrypsin complex in fulminant hepatic failure: relationship to bacterial infection and activation of coagulation

To study the effect of infection, a frequent complication of fulminant hepatic failure (FHF), on the release of elastase from polymorphonuclear leucocytes and its inhibition in circulation we have measured the concentrations of alpha 1-antitrypsin, which binds and inhibits elastase in the circulation, and of elastase-alpha 1-antitrypsin complex, in 30 patients with FHF. Elastase-alpha 1-antitrypsin complex was significantly increased in FHF as compared to controls (303 +/- 51 micrograms/l compared to 37 +/- 5 micrograms/l; n = 10; P less than 0.001) demonstrating activation of leucocytes in FHF. Infection caused greater release of leucocyte elastase, complex levels were significantly greater in patients who were infected when compared to those who were not (463 +/- 84 micrograms/l; n = 13 compared to 180 +/- 46 micrograms/l; n = 17; P less than 0.01). Also patients who survived had significantly lower complex levels than those who did not (212 +/- 49 micrograms/l; n = 18 compared to 440 +/- 94 micrograms/l; n = 12; P less than 0.02). alpha 1-Antitrypsin activity was not significantly different from control subjects (0.99 +/- 0.06 U/ml compared to 0.97 +/- 0.05 U/ml). However alpha 1-antitrypsin activity was significantly higher in patients who survived (1.17 +/- 0.05 U/ml; n = 18) compared to those who did not (0.71 +/- 0.03 U/ml; n = 12; P less than 0.001) and patients who died had significantly lower levels than control subjects (P less than 0.01) indicating the importance of maintenance of normal inhibitor levels in patients with FHF. The leucocyte activation and release of elastase in FHF was linked to activation of the coagulation system; elastase--alpha 1-antitrypsin complex levels correlated significantly with thrombin-antithrombin III complex levels (r = 0.68; P less than 0.001) and inversely with fibrinogen (r = -0.71; P less than 0.001).

Elevated brain concentrations of 1,4-benzodiazepines in fulminant hepatic failure

BACKGROUND

Increased gamma-aminobutyric acid (GABA) neurotransmission has been implicated in the pathogenesis of hepatic encephalopathy. The mechanism by which GABA-ergic activity is increased in hepatic failure is unclear, but recent studies in animals with encephalopathy due to fulminant hepatic failure suggest that GABA-ergic neurotransmission may be increased by the presence of elevated concentrations of benzodiazepine agonists such as diazepam and N-desmethyldiazepam.

METHODS AND RESULTS

Samples of frontal cortex were obtained at autopsy from 11 patients with hepatic encephalopathy who died of acetaminophen-induced fulminant hepatic failure and 8 patients who died of cardiovascular disease or trauma. None of the 19 patients had received benzodiazepines while hospitalized. Chromatographic analyses of extracts of these samples revealed 4 to 19 peaks representing substances that inhibited the binding of a radiolabeled imidazobenzodiazepine ([3H]flumazenil) to its receptors. Several of these peaks had retention times corresponding to those of known 1,4-benzodiazepines. Ultraviolet- and mass-spectroscopic analysis confirmed that two of these peaks represented diazepam and N-desmethyldiazepam. The patients who died of fulminant hepatic failure could be divided into two groups: six who had had significantly elevated brain concentrations (2-fold to 10-fold higher than normal) of substances inhibiting the binding of [3H]flumazenil and five who had normal concentrations.

CONCLUSIONS

Brain concentrations of substances inhibiting the binding of [3H]flumazenil to its receptors are increased in some patients with hepatic encephalopathy due to fulminant hepatic failure. The origin of these substances is unknown, but these findings provide a rational basis for trials of benzodiazepine-receptor antagonists in the management of this disorder.

Antibodies to hepatitis C virus in autoimmune liver disease: evidence for geographical heterogeneity

To resolve conflicting reports about the occurrence of antibodies against hepatitis C virus (HCV) in patients with autoimmune chronic active hepatitis (AI-CAH), sera from UK and Italian patients were tested with the original anti-HCV assay (Ortho) and a novel anti-HCV assay (UBI) based entirely on synthetic HCV peptides. 28 (60%) of 47 Italian patients with type-1 AI-CAH were anti-HCV-positive by Ortho ELISA, 25 of whom were also strongly positive by the UBI assay. 15 (60%) of 25 UK patients with type-1 AI-CAH were HCV-positive by Ortho ELISA but only 2 were positive by the UBI assay. Similarly, 29 (88%) of 33 Italian patients with type-2 AI-CAH, but 0 of 10 UK patients, were very strongly anti-HCV-positive with the UBI assay. Italian patients with AI-CAH appear to have a high frequency of genuine exposure to HCV, whereas seropositivity by the Ortho HCV ELISA in UK patients is likely to represent a false-positive result. These findings indicate important geographical and/or genetic influences in autoimmune liver disease among different populations.

Serum and tissue alpha-L-fucosidase activity in the pre-clinical and clinical stages of hepatocellular carcinoma

1. To assess the value of serum alpha-L-fucosidase (EC 3.2.1.51) as a marker for hepatocellular carcinoma, the activity was measured in patients with hepatocellular carcinoma and in control subjects. 2. Mean serum alpha-L-fucosidase activity was significantly greater in 35 patients with hepatocellular carcinoma (225 +/- 69 nkat/l) than in 35 patients with cirrhosis and 20 normal subjects (134 +/- 30 and 93 +/- 28 nkat/l, respectively). The overlap between hepatocellular carcinoma and cirrhosis, however, was such as to severely limit any value of the enzyme as a diagnostic test. 3. In four cirrhotic patients with hepatocellular carcinoma, an increased enzyme activity was detectable in samples taken up to 66 months before the tumours were diagnosed clinically. 4. The serum activity of alpha-L-fucosidase fell to within the reference range after liver transplantation for hepatocellular carcinoma in three patients and in one of these a subsequent rise was associated with tumour recurrence which was diagnosed at 8 months after the rise in activity. Ineffective cytotoxic chemotherapy was also associated with a progressive rise in serum alpha-L-fucosidase activity. 5. alpha-L-fucosidase activity in tumour tissue was significantly lower than that seen in non-tumour tissue from cirrhotic patients. These reductions may represent increased transport from the tissue and may partly account for the increased serum activity found in some patients with hepatocellular carcinoma.

Association of a precore genomic variant of hepatitis B virus with fulminant hepatitis

A variant of hepatitis B virus has been described recently in HBsAg+ Mediterranean patients who lack HBeAg and who have an unusual and severe form of chronic hepatitis. This variant is unable to produce HBeAg because of the presence of a novel translational stop codon at the end of the precore region of the genome. By direct sequencing of DNA, generated by the polymerase chain reaction, we have evaluated the association between infection with this variant and the fulminant course of hepatitis B. Eighteen patients with fulminant hepatitis B were studied. Of the 15 cases from whose serum viral DNA could be sequenced, the variant was found in the admission sera of 8 of 9 HBeAg- patients but in none of 6 HBeAg+ patients who had fulminant hepatitis B. Patients harboring the variant progressed more rapidly into hepatic encephalopathy, but those infected with the variant strain alone had a greater likelihood of survival than those infected with the normal strain or a mixture. The mutant strain may emerge spontaneously during fulminant hepatitis as occurs in chronic hepatitis B infection during seroconversion from HBeAg to antibody. Alternately, and perhaps less commonly, patients may be infected with the variant ab initio.

Frequency of asymptomatic hepatitis types B and C in an inner city community and relation to possible risk factors

The frequency of asymptomatic carriage of the hepatitis virus types B and C in an inner city area (South London) was assessed in a survey of 1002 subjects attending their General Practitioner for minor, non-hepatic complaints. Ten subjects were seropositive for hepatitis B surface antigen (HBsAg) (1 per cent), but only one, who declined liver biopsy, had any clinical laboratory evidence of hepatitis B virus-related chronic liver disease. Carriage of, and exposure to, hepatitis B virus was significantly more frequent among people born outside the UK/Eire and those with a history of jaundice. Among people of Caribbean origin the frequency of hepatitis B virus markers fell from 31 per cent among those born in the Caribbean to 11 per cent amongst second generation subjects born in this country. Despite careful counselling, offers of further investigation and treatment of those affected, and vaccination of vulnerable children or partners, were often declined. Four percent of the same population had antibodies to the hepatitis C virus using the Ortho anti-hepatitis C virus enzyme-linked immunosorbent assay but this figure fell to 0.9 per cent when a second test, based on synthetic peptides rather than a recombinant antigen, was used. None had any abnormality of standard liver function tests. Chronic asymptomatic carriage of hepatitis, particularly in inner city areas, may be more common than previously recognized. Effective use of antiviral agents and vaccination will be limited until appropriate health education dispels the widespread misconceptions and fears associated with a diagnosis of chronic viral hepatitis.

Antithrombin III supplementation reduces heparin requirement and platelet loss during hemodialysis of patients with fulminant hepatic failure

Previous studies have shown that antithrombin III levels are low in fulminant hepatic failure, and heparin kinetics are abnormal, making control of heparinization difficult during hemodialysis of these patients who are at risk of bleeding. In this study, we have performed a controlled, randomized trial of antithrombin III supplementation on heparin activity, occurrence of bleeding and the platelet count and activation during hemodialysis in 24 patients with fulminant hepatic failure. The treated group of 12 patients was given 3,000 units of antithrombin III before hemodialysis. Antithrombin III supplementation was shown to normalize antithrombin III levels during hemodialysis (prelevels: 0.22 +/- 0.03 U/ml S.E.; at 1 hr 0.99 +/- 0.06 U/ml; p less than 0.001; control prelevels: 0.24 +/- 0.03 U/ml; at 1 hr 0.23 +/- 0.04 U/ml). Total heparin usage was significantly decreased by antithrombin III supplementation (median 5,200 U; range = 2,000 to 13,000) as compared with the control group (median 10,200 U; range = 5,000 to 16,500; p less than 0.005). Blood heparin level (antifactor Xa activity) after the initial bolus was significantly greater in the antithrombin III-supplemented subjects (0.40 +/- 0.07 U/ml compared with 0.22 +/- 0.05 U/ml in the control group; p less than 0.05). The significant reduction in platelet count observed in the control patients (18% +/- 6% at 1 hr; p less than 0.05) did not occur in antithrombin III patients (6% +/- 4% at 1 hr), which was reflected by a lower release of the platelet-specific protein beta-thromboglobulin. Two of 12 patients in both groups showed minor bleeding around vascular access sites during the first hemodialysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Liver transplantation after paracetamol overdose

OBJECTIVE

To evaluate the role of liver transplantation after paracetamol overdose.

DESIGN

Prospective study of consecutive candidates for transplantation and performance of transplantation over 18 months.

SETTING

Liver unit, King's College Hospital, London.

MAIN OUTCOME MEASURES

Fulfilment of indicators of poor prognosis, selection for transplantation, transplantation, survival.

RESULTS

30 of 37 patients considered to have a reasonable prognosis with intensive medical care survived. Of 14 of 29 patients considered to have a very poor prognosis and registered for urgent liver transplantation, six received liver transplants, four of whom survived, while seven died and one survived without a transplant. Three of 15 patients with poor prognostic indicators but not selected for transplantation survived.

CONCLUSION

Liver transplantation will have a definite but limited role in the management of fulminant hepatic failure induced by paracetamol.

Expression of intrahepatic hepatitis D viral antigen in chronic hepatitis D virus infection

To elucidate the biological importance of intrahepatic hepatitis D virus antigen, its expression was correlated with biochemical and histological inflammatory activity in 98 biopsy specimens from 68 patients seropositive for total antibody to the virus. Seventy five specimens were positive for intrahepatic nuclear antigen for HDV antigen accompanied by cytoplasmic HDV antigen in only one biopsy specimen. This group had significantly higher serum transaminase activities and inflammatory activity than the remaining cases that were negative for HDV antigen. Among the group positive for HDV antigen, there was no correlation between the proportion of hepatocytes containing HDV antigen and either serum transaminase activity or histological inflammatory indices. In 22 HDV antigen positive patients who had follow up biopsy specimens taken at a median of two years, the proportion with cirrhosis increased from 36% to 73%. Serum transaminase activities remained the same during this period, but the proportion of HDV antigen positive cells dropped. Follow up of 51 patients showed that 21 died or underwent liver transplantation within three years. The absence of an association between intrahepatic HDV antigen expression and progression of histological liver damage does not support the view that HDV is directly cytopathic to hepatocytes. Immune mediated mechanisms may have a role in the pathogenesis of chronic liver disease related to HDV infection.

Increased tumor necrosis factor-alpha receptor number in chronic hepatitis B virus infection

Production of the antiviral cytokine, tumor necrosis factor-alpha is increased in chronic hepatitis B virus infection, and clinical studies of tumor necrosis factor-alpha have indicated a proviral effect at higher doses. To determine whether this might be related to abnormal cell surface tumor necrosis factor-alpha receptor expression, binding characteristics of cell surface tumor necrosis factor-alpha receptor on peripheral blood mononuclear cells in chronic hepatitis B virus carriers were studied using radioiodinated recombinant tumor necrosis factor-alpha. The specific binding curves generated were analyzed according to the method of Scatchard to determine cell surface receptor numbers and dissociation constants. A single class of cell surface tumor necrosis factor-alpha receptor was demonstrated on peripheral blood mononuclear cells and mononuclear subsets. The median number (range) of cell surface tumor necrosis factor-alpha receptors on peripheral blood mononuclear cells from controls (n = 11), chronic hepatitis B virus patients seropositive for hepatitis B virus DNA (n = 8) and seronegative for hepatitis B virus DNA (n = 8) were 2,329 (range = 1,538 to 3,133), 3,375 (range = 2,300 to 6,718) (p less than 0.01) and 3,113 (range = 2,229 to 5,246) (p less than 0.05) sites/cell, respectively. They all had similar dissociation constants of 8.4 x 10(-10) mol/L (range = 4.1 to 16.9), respectively. Further dissection of the peripheral blood mononuclear cells showed that this increase in cell surface receptor number was confined to the monocyte fraction (p less than 0.01). Plasma tumor necrosis factor-alpha levels in five patients with increased monocyte cell surface tumor necrosis factor-alpha receptor numbers were also elevated.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics and toxicity of intraarterial adriamycin for hepatocellular carcinoma: effect of coadministration of lipiodol

To determine the effect of coadministration of lipiodol on the pharmacokinetics and systemic toxicity of intraarterial Adriamycin in patients with hepatocellular carcinoma, nine patients were studied in detail. Each received two courses of a bolus injection of Adriamycin (60 mg/m2), in one of which the Adriamycin was mixed with 10 ml of lipiodol. Analysis of the paired data, and additional 'non-paired' data from a further seven patients, showed that there was no significant difference in the area under the concentration-time curve for Adriamycin or adriamycinol or, in the case of Adriamycin, the terminal half-life. Likewise the fall in haemoglobin concentration, white cell count and platelet count following treatment, and the degree of nausea and vomiting were not significantly different. Comparison with a series of 12 patients receiving intravenous Adriamycin, in the same dose schedule, revealed no difference in terms of pharmacokinetic parameters or toxicity with intraarterial administration of Adriamycin, with or without lipiodol.

Cardiovascular and catecholamine responses to head-up tilt in the diagnosis of recurrent unexplained syncope in elderly patients

To increase understanding of the mechanisms causing syncope in patients over the age of 60, hemodynamic and hormonal responses to 60 minutes of 60 degree head-up tilt were examined in 10 patients with recurrent syncope of unknown origin and five controls with no history of syncope. Nine of 10 patients and all five controls experienced orthostatic intolerance on the tilt table. Syncope or pre-syncope occurred later in controls than in those syncope patients who had exact reproduction of their clinical symptoms (median time 52 versus 22 minutes, P = 0.05). Three different mechanisms of orthostatic intolerance were identified in the 14 subjects: (1) vasovagal syncope, n = 9 (sudden hypotension +/- bradycardia); (2) dysautonomic syncope, n = 3 (immediate and gradual parallel declines in both systolic and diastolic pressures with blunted increase in heart rate); (3) psychogenic or vestibular reaction, n = 2 (orthostatic intolerance without hemodynamic changes). Vasovagal syncope patients showed a significant increase in plasma norepinephrine from baseline to maximum level during tilt (100 +/- 39% increase, P = 0.03) and a subsequent decrease at the time of syncope (30 +/- 5% decrease, P = 0.01), while plasma epinephrine increased markedly from baseline to the time of syncope (827 +/- 154% increase, P = 0.0003). Dysautonomic syncope patients had lower supine levels of norepinephrine compared to vasovagal syncope patients (182 +/- 30 versus 614 +/- 146 pg/mL, P = 0.008) and no significant change in norepinephrine over time; epinephrine levels increased significantly less than in vasovagal patients (net change 38 +/- 8 versus 189 +/- 56 pg/mL, P = 0.008).(ABSTRACT TRUNCATED AT 250 WORDS)

Impaired binding properties of thyroxine-binding globulin in hepatocellular carcinoma and chronic liver disease

To determine the factors underlying the apparent reduction in binding ability of thyroxine-binding globulin in hepatocellular carcinoma, hormone-binding characteristics were further examined in patients with this disease and in control subjects. No differences in affinity constants with respect to triodothyronine or serum thyroxine-binding globulin from hepatocellular carcinoma, cirrhotic and normal subjects were found. The affinity for thyroxine was significantly reduced in hepatocellular carcinoma (0.41 +/- 0.13 x 10(10) mol-1) and cirrhotic (0.65 +/- 0.1 x 10(10) mol-1) patients compared with normal subjects (0.94 +/- 0.7 x 10(10) mol-1). Investigations carried out on liver tissue obtained from patients with hepatocellular carcinoma and chronic liver disease showed that thyroxine-binding globulin within tumor tissue was elevated and bound less exogenous tracer hormone compared with that obtained from nontumor tissue. Tumor-derived thyroxine-binding globulin with altered binding properties is, at least partly, responsible for the abnormal behavior of the serum protein in patients with hepatocellular carcinoma.

Prognostic significance of pre-S2 antigen and antibody in fulminant hepatitis B. Evidence for heterogeneous serological responses

Serial sera were collected prospectively and from early on in the clinical course of ten patients with fulminant hepatitis B. These were analysed for HBV DNA (dot-blot technique), HBsAg, HBeAg, pre-S2-Ag and their respective antibodies. Two patterns emerged in nine of the patients. The first and well-recognised pattern of rapid clearance of antigens and appearance of antibodies was seen in four patients, all of whom survived. The second pattern seen in five patients was one of persistence of HBsAg and pre-S2 antigen and failure to detect antibodies but only one patient survived. The first pattern may reflect a more rapid cessation of virus replication and this may favour liver cell regeneration and recovery. In contrast, the second pattern may indicate continuing virus replication and liver cell damage which could contribute to the high mortality in some patients with fulminant hepatitis B.

Stenoses of vascular anastomoses after hepatic transplantation: treatment with balloon angioplasty

Vascular complications after liver transplantation include occlusion or stenosis at the sites of anastomosis in the hepatic artery, portal vein, and vena cava. From our experience with more than 600 liver transplants, vascular stenoses have been identified in 10 patients and treated by balloon angioplasty in nine. Three patients with hepatic artery stenosis and deteriorating graft function were treated by balloon angioplasty with a coaxial technique. A specially designed catheter facilitated a successful femoral artery approach. Portal vein stenoses in three patients resulted in portal hypertension. These were treated by balloon dilatation via transhepatic catheterization of the portal vein. Stenoses of the suprahepatic caval anastomosis were dilated in three patients with severe lower limb edema. Technical success was achieved in all three cases of hepatic artery stenosis with improvement in graft function. Recurrent stenoses in two patients were successfully treated with repeated dilatations. Portal hypertension resolved in two of three patients after portal venoplasty. Dilatation of a caval stenosis resulted in the resolution of leg edema in all three cases. Repeated dilatation was required in one case. No reduction in the portal venous pressure gradient occurred after venoplasty in one case, and an ultimately fatal caval thrombosis developed in one patient with caval stenosis before venoplasty could be performed. Our experience suggests that balloon angioplasty of arterial and venous stenoses complicating hepatic transplantation carries little risk and is a useful procedure for the treatment of these problems.

Improvement by acetylcysteine of hemodynamics and oxygen transport in fulminant hepatic failure

BACKGROUND

When administered early after an overdose of acetaminophen, intravenous acetylcysteine prevents hepatic necrosis by replenishing reduced stores of glutathione. How acetylcysteine improves the survival of patients with established liver damage induced by acetaminophen, however, is unknown. This study was undertaken to determine whether the beneficial effect of acetylcysteine under such circumstances could be due to enhancement of oxygen delivery and consumption.

METHODS

We studied the effect of acetylcysteine on systemic hemodynamics and oxygen transport in 12 patients with acetaminophen-induced fulminant hepatic failure and 8 patients with acute liver failure from other causes. The acetylcysteine was given in a dose of 150 mg per kilogram of body weight in 250 ml of 5 percent dextrose over a period of 15 minutes and then in a dose of 50 mg per kilogram in 500 ml of 5 percent dextrose over a period of 4 hours; measurements were made before treatment began and after 30 minutes of the regimen.

RESULTS

In the patients with acetaminophen-induced liver failure, the infusion of acetylcysteine resulted in an increase in mean oxygen delivery from 856 to 975 ml per minute per square meter of body-surface area (P = 0.0036), due to an increase in the cardiac index from 5.6 to 6.7 liters per minute per square meter (P = 0.0021). Mean arterial pressure rose from 88 to 95 mm Hg (P = 0.0054) despite a decrease in systemic vascular resistance from 1296 to 1113 dyn.sec.cm-5 per square meter (P = 0.027). There was an increase in oxygen consumption from 127 to 184 ml per minute per square meter (P = 0.0007) associated with an increase in the oxygen-extraction ratio from 16 to 21 percent (P = 0.022). The effects in the patients with acute liver failure from other causes were similar.

CONCLUSIONS

The increase in oxygen delivery and consumption in response to acetylcysteine may account for its beneficial effect on survival in patients with fulminant hepatic failure induced by acetaminophen.

Hepatic interferon-alpha gene transcripts and products in liver specimens from acute and chronic hepatitis B virus infection

In this study we have examined the localization of interferon-alpha in liver tissue from acute and chronic hepatitis B virus carriers to establish whether the defect in interferon-alpha production reported in chronic hepatitis B virus infection is at a pretranscriptional or posttranscriptional level using in situ hybridization and immunohistochemical techniques. Interferon-alpha messenger RNA transcripts and the immunoreactive protein were abundant in liver tissue and in particular in hepatocytes from patients with acute hepatitis B virus infection who subsequently recovered. In contrast interferon-alpha polypeptide was present in a significantly lower number of sinusoidal cells, mononuclear cells and hepatocytes in chronic hepatitis B virus carriers. Although a high proportion of patients with chronic hepatitis B virus infection had cells that expressed interferon-alpha messenger RNA transcripts, the number of such cells was significantly less than in acute hepatitis B virus infection, indicating that the defect in the hepatic interferon-alpha synthesis is at the level of gene activation. Furthermore, using double immunohistochemical staining, the number of hepatocytes containing HBcAg correlated inversely with the proportion of neighboring sinusoidal cells expressing interferon-alpha. These data support previous observations that interferon-alpha production is reduced in chronic hepatitis B virus infection and are consistent with the view that this cytokine is important in the clearance of the virus.

Sampling Asian minorities to assess health and welfare

STUDY OBJECTIVE

The aims were (1) to sample a specified subgroup of the Asian minority; (2) to give proper representation to those outside the areas of concentration; and (3) to evaluate the costs and benefits of the method.

DESIGN

Glasgow postcodes with varying concentrations of Asians were sampled, and 173 Asians aged 30-40 were interviewed after household screening of 1439 Asian names identified on the electoral roll or valuation roll. Areas with few Asians, and households with two or more members aged 30-40, were undersampled, and then reweighted.

MEASUREMENTS AND MAIN RESULTS

Nurse measures of blood pressure, lung function, and body mass were taken, and selected interview measures of health and social background are reported. Substantial differences in blood pressure, reported health, and social background were revealed between Asians in areas of concentration and those in areas of dispersion. Loss in effective sample size due to undersampling and reweighting was 4-5% in the case of the area sampling, 13% in the case of the household sampling. Losses of potential sample members through under registration were probably less than 6%.

CONCLUSIONS

The present sampling method targets subgroups successfully, and improves on sampling in areas of concentration, in that it enables dispersed members of the minority, who differ in crucial indices of health and social position, to be represented. The costs of the method are acceptable.