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Biomedical subjects

G J Alexander

Publications and source records attributed to G J Alexander.

At least 127 records · Page 7Linked to original sources
PubMed1991

Rapid detection of hepatitis B virus DNA in liver tissue by in situ hybridisation and its combination with immunohistochemistry for simultaneous detection of HBV antigens.

A rapid technique using a non-radioactive receptor molecule (digoxigenin) for intrahepatic hepatitis B virus (HBV) DNA detection using in situ hybridisation was developed. It can be adapted for use in combination with standard immunohistochemistry for simultaneous detection of both HBV DNA and HBV antigens. The total time required for dual detection of HBV antigens and HBV DNA starting from paraffin wax liver sections was two working days. A good signal to background ratio for the detection of HBV DNA was always obtained using this labelling. This technique is cheap, safe, and relatively simple which makes it an ideal tool for the detection of intrahepatic HBV DNA for both routine diagnostic purposes and in research.

DNA, Viral↗
PubMed1991

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.

Adult↗
PubMed1991

Leukotriene and prostaglandin production after infusion of tumour necrosis factor in man.

Tumor necrosis factor-alpha is believed to be an important mediator of endotoxaemia and septic shock, the effects of which are thought to be mediated through the generation of cysteinyl-leukotrienes, thromboxane A2 and other prostanoids. We have investigated the production of these eicosanoids and also that of prostacyclin in vivo after infusion of tumor necrosis factor-alpha into 4 subjects with a chronic hepatitis B virus infection. This resulted in plasma TNF levels considerably greater than those observed in septic shock. Urinary excretion rate of leukotriene E4 increased by 2 to 3-fold in all subjects by 8 h following TNF infusion. Urinary excretion of thromboxane B2 and 6-oxo-prostaglandin F1 alpha, however, increased in the first 4 h in 3/4 subjects by 2 to 40-fold and returned towards baseline by 8 h. Excretion of the hepatic metabolite, 2,3-dinor 6-oxo-prostaglandin F1 alpha, increased in all subjects (2 to 4-fold at 4h). We conclude that there is increased production of cysteinyl leukotrienes, thromboxane A2 and prostacyclin after infusion of tumour necrosis factor into man.

Adult↗
PubMed1991

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.

Adult↗
PubMed1991

Interferon-alpha receptor expression and regulation in chronic hepatitis B virus infection.

Interferon-alpha elicits antiviral and immunoregulatory activities by binding to specific receptors on the cell surface. In this study, binding characteristics of interferon-alpha to peripheral blood mononuclear cells in patients with chronic hepatitis B virus infection were studied using radioiodinated recombinant interferon-alpha 2b to determine interferon-alpha receptor numbers and dissociation constants. A single class of interferon-alpha receptor was demonstrated on peripheral blood mononuclear cells and mononuclear subsets. Peripheral blood mononuclear cells from patients with chronic hepatitis B virus infection (n = 20) and controls (n = 16) expressed a similar number of interferon-alpha receptors (484 +/- 175 vs. 511 +/- 168 sites/cell respectively, p = NS) with a similar dissociation constant (dissociation constant approximately 0.2 to 0.7 nmol/L). Expression of interferon-alpha receptors was similar in monocyte-enriched and lymphocyte-enriched fractions in both groups. Similar changes were observed in patients receiving alpha-interferon therapy. There was no correlation between interferon-alpha receptors expression and serum transaminase, serum HBsAg, serum HBV DNA, liver histological findings or the response to interferon-alpha therapy. After incubation of lymphocytes in vitro with interferon-alpha 2b (10 to 1,000 U/ml), interferon-alpha receptors number dropped by 42% to 80%, but this was associated with an increase in binding affinity (dissociation constant approximately 0.05 to 0.15 nmol/L) in both patients and controls. There was significant delay in the initial phase of receptor recovery in the patients with chronic hepatitis B virus infection compared with normal controls (days 1 and 2, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Effect of interferon-gamma on hepatitis B viral antigen expression in primary hepatocyte culture.

Interferon-alpha has been shown recently to selectively enhance hepatocyte expression of HBsAg/pre-S2 in chronic hepatitis B virus infection in a way that may enhance immune recognition. To determine the effect of interferon-gamma on hepatitis B virus antigen expression, hepatocytes isolated from patients with chronic hepatitis B virus infection were incubated in the absence or presence of interferon-gamma and viral antigen expression was assessed by both radioimmunoassay and immunocytochemistry using appropriate monoclonal antibodies. Interferon-gamma inhibited the expression of all hepatitis B virus antigens tested. Intracellular HBsAg measured by radioimmunoassay of sonicated hepatocytes fell by 29% with 1 U/ml (p less than 0.01) and 36% with 10 U/ml of interferon-gamma (p less than 0.001) compared with control treatment. Secreted HBsAg was reduced by 19% with 10 U/ml of interferon-gamma (p less than 0.01). Intracellular HBeAg was also decreased by 29% with 1 U/ml (p less than 0.05) and 42% with 10 U/ml of interferon-gamma (p less than 0.05), but no significant change was found in the amount of secreted HBeAg. The proportion of hepatocytes containing various hepatitis B virus antigens and the intracellular viral antigen staining densities also fell significantly with interferon-gamma incubation. Interestingly, the addition of interferon-gamma abolished the augmenting effect of interferon-alpha on intracellular HBsAg. These data indicate that interferon-gamma, in contrast to interferon-alpha, has an inhibitory effect on hepatocyte expression of all hepatitis B virus antigens including HBsAg/pre-S2, suggesting that this may be one factor that accounts for their difference in clinical activity in patients with chronic hepatitis B virus infection.

Cells, Cultured↗
PubMed1991

IgA class antibodies to hepatitis delta virus antigen in acute and chronic hepatitis delta virus infections.

Sera from 31 patients with chronic hepatitis delta virus infection and 18 patients with acute hepatitis delta virus infection were examined for IgA class antibodies to this virus using a newly developed enzyme immunoassay. IgA antibody to hepatitis D virus was detected in 21 (67.7%) of 31 patients with chronic delta viral hepatitis, but in only 1 (5.6%) of the 18 patients with acute infection (p less than 0.0005). Of the 21 patients with chronic delta hepatitis with IgA antibody to hepatitis D virus, 19 (90.5%) had moderate-to-severe activity on liver biopsy: 18 of the 21 had histological features of chronic active hepatitis and three had chronic lobular hepatitis. In all, 23 patients with chronic delta hepatitis had moderate-to-severe activity, and 19 (82.6%) had IgA antibody to hepatitis D virus. No statistically significant correlations were found between IgA antibody to hepatitis D virus and biochemical markers of liver injury (p greater than 0.4), or the presence of hepatitis delta virus antigen in liver biopsies (p greater than 0.2), in the patients with chronic delta hepatitis. The finding that IgA antibody to hepatitis D virus was almost exclusively associated with chronic hepatitis delta virus infection and correlated independently with moderate-to-severe histological activity (with a specificity of 90.5% and a sensitivity of 82.6%) suggests that this antibody might be a useful serological marker of underlying liver damage in chronic delta hepatitis.

Acute Disease↗
PubMed1991

Hepatic histological findings after transplantation for chronic hepatitis B virus infection, including a unique pattern of fibrosing cholestatic hepatitis.

Long-term follow-up of 27 patients with hepatitis B virus-related chronic liver disease treated by transplantation showed that 23 had hepatitis B virus recurrence. In 13 patients late changes in the grafts were similar to those described in other series: minor abnormalities in five cases, chronic active hepatitis in five cases and non-hepatitis B virus-related graft dysfunction in three cases. Three patients had incomplete histological follow-up. Analysis of the histological changes and viral antigen expression in six cases revealed a distinct and novel pattern termed fibrosing cholestatic hepatitis. Development of fibrosing cholestatic hepatitis was associated with rapidly progressive graft dysfunction. It is postulated that this pattern of fibrosing cholestatic hepatitis develops because of a high cytoplasmic expression of viral antigens, including HBsAg. The remaining case had some features of fibrosing cholestatic hepatitis. The main histological features of this unique syndrome include thin, perisinusoidal bands of fibrosis extending from portal tracts to surround plates of ductular-type epithelium; prominent cholestasis; ground-glass transformation; and ballooning of hepatocytes with cell loss and mild mixed inflammatory reaction.

Adult↗
PubMed1991

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.

Acute Disease↗
PubMed1990

Serial prothrombin time as prognostic indicator in paracetamol induced fulminant hepatic failure.

OBJECTIVE: To find out whether changes in the daily prothrombin time are of prognostic importance in patients with paracetamol induced fulminant hepatic failure. DESIGN: Retrospective study. SETTING: The Liver Unit, King's College Hospital, London. PATIENTS: 150 Consecutive patients with paracetamol induced fulminant hepatic failure admitted between October 1986 and February 1989. MAIN OUTCOME MEASURE: Death. RESULTS: Of the 150 patients, 72 (48%) died. In all, 34 of the 37 (92%) patients with a peak prothrombin time of greater than or equal to 180 seconds died as did 20 of the 41 (49%) with a time of 130-179 seconds, nine of the 25 (36%) with a time of 90-129 seconds, and nine of the 47 (19%) with a time of less than 90 seconds. Of the 42 patients with a continuing rise in prothrombin time between days 3 and 4 after overdose, 39 died (93%) compared with 21 of the 96 (22%) in whom the prothrombin time fell. CONCLUSIONS: These data indicate that a continued increase in prothrombin time on day 4 after overdose and a peak prothrombin time of greater than or equal to 180 seconds identify at an early stage those patients with a less than 8% chance of survival. Liver transplantation should be considered in patients meeting either of these criteria.

Acetaminophen↗
PubMed1990

Improved outcome of paracetamol-induced fulminant hepatic failure by late administration of acetylcysteine.

The influence of acetylcysteine, administered at presentation to hospital, on the subsequent clinical course of 100 patients who developed paracetamol-induced fulminant hepatic failure was analysed retrospectively. Mortality was 37% in patients who received acetylcysteine 10-36 h after the overdose, compared with 58% in patients not given the antidote. In patients given acetylcysteine, progression to grade III/IV coma was significantly less common than in those who did not receive the antidote (51% vs 75%), although the median peak prothrombin time was similar for both groups. Whether the beneficial effect is related to replenishment of glutathione stores or a consequence of another hepatic protective mechanism of acetylcysteine requires further study.

Acetaminophen↗
PubMed1990

Increased plasma tumor necrosis factor in severe alcoholic hepatitis.

STUDY OBJECTIVE: To determine whether elevated tumor necrosis factor levels contribute to the clinical manifestations and complications of severe acute alcoholic hepatitis and to evaluate the relation between tumor necrosis factor and plasma levels of endotoxin and interleukin-1 beta. DESIGN: Prospective, controlled study. SETTING: The liver unit of a university teaching hospital. PATIENTS: We studied 21 patients with acute severe alcoholic hepatitis. There were four control groups: patients with inactive alcoholic cirrhosis, alcoholic persons without liver disease, patients with impaired renal function, and normal subjects. MEASUREMENTS AND MAIN RESULTS: With one exception, patients with alcoholic hepatitis had higher tumor necrosis factor levels (mean, 26.3 ng/L; 95% CI, 21.7 to 30.9) than normal subjects (6.4 ng/L; CI, 5.4 to 7.4). Patients who subsequently died had a higher tumor necrosis factor level (34.7 ng/L; CI, 27.8 to 41.6) than survivors (16.6 ng/L; CI, 14.0 to 19.2). In patients with alcoholic hepatitis, tumor necrosis factor levels correlated positively with serum bilirubin (r = 0.74; P = 0.0009) and serum creatinine (r = 0.81; P = 0.0003). Patients with alcoholic hepatitis had higher tumor necrosis factor levels than patients with inactive alcoholic cirrhosis (11.1 ng/L; CI, 8.9 to 13.3) and severely alcoholic persons without liver disease (6.4 ng/L; CI, 5.0 to 7.8). Patients with abnormal renal function had lower tumor necrosis factor levels (14.1 ng/L; CI, 5.4 to 22.8) than patients with alcoholic hepatitis. Serial samples obtained during a 1-week period from patients with alcoholic hepatitis showed no significant change in tumor necrosis factor when patients who died were compared with survivors. No correlation was found between tumor necrosis factor and plasma endotoxin. Levels of interleukin-1 beta did not exceed 20 ng/L. CONCLUSIONS: Elevations in tumor necrosis factor in alcoholic hepatitis are most marked in severe cases, suggesting that tumor necrosis factor plays a role in the pathogenesis.

Alcoholism↗
PubMed1990

Spontaneous production of tumour necrosis factor alpha and interleukin-1 beta during interferon-alpha treatment of chronic HBV infection.

Seven chronic carriers of hepatitis B virus (HBV) were studied during treatment with interferon-alpha to determine whether tumour necrosis factor alpha (TNF alpha) or interleukin-1 beta (IL-1 beta) contributed to the elimination of HBV. Four patients responded to interferon-alpha with clearance of HBeAg and permanent inhibition of HBV replication within 3-12 weeks; in each of these patients, the changes were accompanied by substantial rises in spontaneous in-vitro production of TNF alpha and IL-1 beta by peripheral blood mononuclear cells from previously undetectable levels. There was little or no change in spontaneous TNF alpha and IL-1 beta production in the three patients who did not lose HBeAg in response to interferon-alpha. These findings suggest that TNF alpha and IL-1 beta may contribute to the permanent elimination during interferon-alpha treatment of hepatocytes supporting viral infection and that the therapeutic potential of these cytokines is worthy of investigation.

Adult↗
PubMed1990

Detection of hepatitis B virus antigens in liver tissue. A relation to viral replication and histology in chronic hepatitis B infection.

The expression of hepatitis B virus antigens was studied by double staining liver tissue with appropriate antisera and correlated with serum hepatitis B viral DNA and histology in 28 patients with disease related to chronic hepatitis B virus infection. The cellular localization of hepatitis B core and hepatitis B e antigens generally coincided, but there were important differences at a subcellular level. Thus, hepatitis B e antigen was detected in nuclei and/or cytoplasm but strong cytoplasmic hepatitis B e antigen was associated with a high serum hepatitis B viral DNA (P = 0.0017) but not with active liver disease. Hepatitis B core antigen could also be detected in nuclei and/or cytoplasm, but strong cytoplasmic hepatitis B core antigen expression, exceeding that of hepatitis B e antigen, was associated with active liver disease (P = 0.041) and not with serum hepatitis B virus DNA. The proportion of hepatocytes expressing hepatitis B surface antigen correlated inversely with the serum titer (P = 0.0017), whereas hepatitis B surface and nucleocapsid antigens were usually expressed independently. The data support the hypothesis that cytoplasmic hepatitis B core antigen and not hepatitis B e antigen is the target for immune system-mediated cytolysis of hepatocytes. Cytoplasmic hepatitis B e antigen is not associated with liver damage but is instead associated with high levels of hepatitis B virus replication.

Antibodies, Monoclonal↗
PubMed1990

Failure of insulin and glucagon infusion to stimulate liver regeneration in fulminant hepatic failure.

A randomised controlled trial of insulin and glucagon infusion was carried out in 18 patients in grade III or IV coma from fulminant hepatic failure due to viral or drug-induced hepatic necrosis to see whether mortality could be reduced by stimulating hepatic regeneration. Nine patients received a continuous infusion of insulin 3 U/h and glucagon 200 micrograms/h made up in 5% dextrose containing 1% human albumin solution (HAS) while controls received 5% dextrose and HAS alone. Baseline plasma insulin and glucagon levels were comparably raised in both groups and, on infusion, rose significantly higher in the insulin- and glucagon-treated patients compared to controls. Two control and one treated patient recovered. Median survival time from enrolment to death was similar for insulin- and glucagon-treated patients and controls--2 and 3 days, respectively. Insulin and glucagon therapy did not enhance hepatic synthetic function, as measured by a fall in prothrombin time or a rise in alpha-fetoprotein; nor did it stimulate hepatic regeneration, only one patient in each group showed histological evidence of hepatic regeneration at post-mortem.

Adult↗