Reduction of ferricytochrome C may underestimate superoxide production by monocytes

Superoxide production by stimulated phagocytes is commonly measured by reduction of ferricytochrome C, with specificity of the assay assumed if the reaction is inhibited by superoxide dismutase (SOD). Most preparations of ferricytochrome C contain a small proportion in the reduced (ferro) form, and this is also formed by the reaction of ferricytochrome C with superoxide. The generation of other reactive oxygen intermediates, such as hydrogen peroxide or hydroxyl radical, could cause oxidation of ferrocytochrome C and consequent underestimation of superoxide production. In support of this, it has been demonstrated that exogenous catalase enhanced the reduction of ferricytochrome C by phorbol myristate acetate (PMA)-stimulated human monocytes. Control experiments confirmed that this was due to enhanced detection rather than increased production of superoxide. In addition, SOD was found to promote oxidation of ferrocytochrome C by PMA-stimulated human monocytes, but this was also inhibited by catalase. These effects of catalase and SOD on ferricytochrome C reduction/ferrocytochrome C oxidation were also demonstrated when superoxide was produced independently of monocytes by a xanthine and xanthine oxidase generating system. It is concluded that the assay of superoxide, using 'SOD inhibitable' reduction of ferricytochrome C, underestimates superoxide production.

Patients with bone marrow failure demonstrate decreased cutaneous reactivity to human C5a

In vivo studies have shown that human C5a, a potent complement-derived anaphylatoxin and chemoattractant, produces immediate inflammatory reactions following intradermal injection in human skin. At concentrations within its potential physiologic range, intradermal injection of C5a elicits immediate wheal and flare reactions, increased vascular permeability, mast cell degranulation, and neutrophil-rich infiltrates. To assess the relative contribution of interacting cellular elements to C5a-induced inflammation in normal human skin, purified human C5a was tested intradermally in 8 patients with bone marrow failure (BMF). Reactions to C5a in patients with BMF were compared with responses at identical test sites in healthy volunteers and other patients with cutaneous disorders. Patients with BMF demonstrated significantly less wheal and flare reactivity following intradermal injection of C5a than controls (p less than 0.05 and less than 0.02, respectively). In these studies, patients with the greatest cytopenia generally showed the least cutaneous reactivity to human C5a. Biopsies of C5a test sites in patients with BMF revealed an absence of leukocytes in marked contrast to neutrophil-rich infiltrates observed at test sites in healthy volunteers. Avidin-fluorescent and/or Giemsa staining of skin biopsies revealed no difference between the number of dermal mast cells in patients with BMF and samples of normal human skin. In addition, skin test studies with histamine (2 micrograms) and morphine (5 micrograms) performed to assess cutaneous vascular and mast cell responsiveness in patients with BMF, normal volunteers and controls with rhinitis revealed no significant differences in cutaneous reactivity to these pharmacologic agents. These in vivo studies demonstrate that patients with BMF specifically exhibit decreased cutaneous reactivity to human C5a and suggest that neutrophils make an important and an immediate contribution to inflammatory responses elicited by this anaphylatoxin.

Oedema of the ileum: a possible manifestation of food allergy

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Depressed selenium and vitamin E levels in an alcoholic population. Possible relationship to hepatic injury through increased lipid peroxidation

Serum selenium and vitamin E levels have been measured in subjects with established alcoholic liver disease, in alcoholics within the community, and in appropriate controls. Both serum selenium and vitamin E levels were shown to be significantly depressed (P less than 0.01) in the alcoholic study groups and serum selenium was more markedly depressed in subjects with established liver disease (controls, serum selenium 108 +/- 13 micrograms/liter, vitamin E 27.6 +/- 7.2 mumol/liter; community alcoholics, serum selenium 94 +/- 19 micrograms/liter, vitamin E 15.3 +/- 3.4 mumol/liter; alcoholic liver disease, serum selenium 78 +/- 15 micrograms/liter, vitamin E 14.7 +/- 5.6 mumol/liter). Depressed serum selenium levels correlated closely with poor nutritional status (r = 0.91). There were no changes in serum glutathione peroxidase activity. Liver disease activity, as judged by transaminase (AST), was more markedly abnormal in subjects with combined vitamin E and selenium deficiency compared to those with normal levels or isolated deficiencies (no deficiency, AST 48 +/- 19 units, combined deficiency, AST 75 +/- 21 units, P less than 0.03). Serum lipid peroxides were elevated in those with combined deficiency and the values correlated significantly with serum transaminases (r = 0.40, P = 0.03).

Hepatic regeneration and metabolism after partial hepatectomy in normal rats: effects of insulin therapy

The effect of insulin therapy on liver regeneration has been studied in normal fed rats 12, 24 and 48 h after partial hepatectomy. Dry weight of regenerating liver increased between 12 and 48 h after partial hepatectomy and was unaffected by insulin therapy. [6-3H] Thymidine uptake peaked at 24-h (24.7 +/- 2.4% of total liver cells) and insulin treatment had no additional effect. At 12-h after partial hepatectomy, hepatic [ATP] was decreased 15%, while [ADP] and [AMP] were increased 47% and 83% respectively compared with sham-operated animals. Partial hepatectomy also caused an increase in hepatic [triglyceride], a decrease in hepatic [glycogen] and an increase in the levels of glucose and several glycolytic intermediates. The hepatic redox ratios, [lactate]:[pyruvate] and [3-hydroxybutyrate]:[acetoacetate], were elevated. Insulin therapy had only minor effects on hepatic adenine nucleotide levels, intermediary metabolite concentrations or intrahepatic redox ratios after partial hepatectomy. These findings suggest a decreased hepatic intracellular energy state in regenerating liver; insulin therapy in normal rats does not influence this metabolic change nor the regenerative response.

Hepatic regeneration and metabolism after partial hepatectomy in diabetic rats: effects of insulin therapy

The effect of insulin deficiency on liver regeneration has been assessed in untreated v. insulin-treated streptozotocin (65 mg kg-1) diabetic rats, 12, 24 and 48 h after partial hepatectomy. Dry weight of regenerating liver increased from 12 to 48 h after partial hepatectomy and insulin treatment caused a further minor increase at 24 h. [6-3H]Thymidine uptake in untreated rats peaked at 24 h (12.5 +/- 3.4% of total cells labelled). Insulin therapy produced a delayed 168% rise in uptake at 48 h. Insulin deficiency alone in sham-operated animals caused a 33% decrease in hepatic [ATP], while [ADP] rose by 43% and [AMP] by 86% at 12 h. Partial hepatectomy produced only minor further abnormalities in untreated animals. Insulin therapy increased hepatic [ATP] and decreased [ADP] and [AMP] 12 h after partial hepatectomy, but [ATP] remained decreased (15%) and [ADP] and [AMP] increased (45% and 73% respectively) compared with insulin-treated sham-operated controls. Metabolite changes observed after partial hepatectomy in untreated animals, including a decrease in hepatic [glycogen] and increases in [triglyceride] and the ratios of [lactate]:[pyruvate] and [3-hydroxybutyrate]:[acetoacetate], were partially reversed by insulin treatment. Insulin deficiency thus impairs regeneration after partial hepatectomy and magnifies the decline in hepatic intracellular energy state and the metabolite changes associated with liver regrowth.

Corynebacterium parvum-elicited hepatic macrophages demonstrate enhanced respiratory burst activity compared with resident Kupffer cells in the rat

We have recently demonstrated that release of oxygen-derived free radicals by activated hepatic macrophages may be involved in the pathogenesis of a rat model of liver injury induced by Corynebacterium parvum and endotoxin. In the present study we have compared the respiratory burst activity of isolated normal rat Kupffer cells with that of hepatic macrophages elicited by C. parvum. Superoxide production (O2-.) and glucose oxidation via the hexose monophosphate shunt (HMPS) were low in normal Kupffer cells, but were significantly increased (O2-. 2.1-fold, HMPS 1.7-fold) by phorbol myristate acetate, a stimulant of the respiratory burst. Corynebacterium parvum-elicited hepatic macrophages demonstrated significantly enhanced superoxide production and HMPS activity compared with normal Kupffer cells, both in the absence of specific stimuli (O2-. 3.3-fold, HMPS 5.3-fold) and after exposure to phorbol myristate acetate (O2-. 4.5-fold, HMPS 5.3-fold). These results demonstrate that normal Kupffer cells are capable of exhibiting respiratory burst activity, but this is markedly increased for hepatic macrophages elicited by an inflammatory stimulus.

Failure of sulfites to produce clinical responses in patients with systemic mastocytosis or recurrent anaphylaxis: results of a single-blind study

Although sulfite sensitivity can precipitate asthma in a subpopulation of subjects with asthma, its role in precipitating anaphylaxis or as a nonspecific mast cell degranulator in systemic mastocytosis has not been examined. To evaluate critically the importance of sulfites in these diseases, eight patients with systemic mastocytosis and 25 patients with unexplained, recurrent anaphylaxis were challenged in a single-blind fashion; sodium bisulfite in capsules was administered in increasing doses of 1, 5, 10, 25, 50, 100, and 200 mg every 30 minutes. On separate occasions a liquid suspension of 200 mg of sodium bisulfite was administered to one patient with systemic mastocytosis and nine patients with anaphylaxis. Vital signs, pulmonary function tests, plasma histamine levels, and clinical reactions were monitored. There were no observable responses in either the mastocytosis group or in 23 of 25 patients in the anaphylaxis group. Two patients in the anaphylaxis group with initial positive challenges had similar symptoms on subsequent placebo challenge. One subject with asthma and with a history suggestive of sulfite sensitivity responded to oral challenge with 5 mg of sodium bisulfite and 100 micrograms of sodium bisulfite intradermally with a dramatic reduction in FEV, requiring treatment with bronchodilators. A comparison of baseline plasma histamine levels with those obtained after the sulfite challenge procedure in each category demonstrated a significant rise (p less than 0.05) in the systemic mastocytosis group. The overall level of significance determined by applying paired sample t tests to the histamine data from all subjects was p less than 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxygen-derived free radicals promote hepatic injury in the rat

We have investigated the possible protective effect of superoxide dismutase and allopurinol in a rat model of mild and severe hepatic necrosis produced by Corynebacterium parvum with or without endotoxin. Histology showed a sinusoidal mononuclear cell infiltrate with multiple granulomata but variable degrees of hepatic necrosis. In the severe hepatic injury model there was a reduction in mortality, associated with a decrease in histologic and biochemical evidence of hepatic necrosis, after treatment with superoxide dismutase. This protective effect was not demonstrated with partially heat-inactivated superoxide dismutase. In the mild hepatic injury model similar trends in reduction of serum levels of hepatic enzymes were observed after treatment with both superoxide dismutase and allopurinol. These results indicate that oxygen-derived free radicals may play an important role in the pathogenesis of hepatic injury in the rat.

Loneliness among the elderly: a causal approach

The purpose of this study was to develop and assess a causal model of loneliness among a national probability sample of noninstitutionalized elderly adults. Path analysis was used to test the causal model. The findings indicated that marital status, self-perceived health status, income, social activity levels, and a sense of social fulfillment directly predict feelings of loneliness. The social fulfillment variable, however, was the most important predictor. An interesting finding was that age had no notable direct or indirect effect on feelings of loneliness.

Drug influences on rat hepatic macrophage enzyme production and release in vitro

Drug influences on hepatic macrophage enzyme release have been investigated using a rat model of macrophage recruitment and activation. N-acetyl-glucosaminidase (NAG), a lysosomal enzyme, and plasminogen activator (PA), a cytosolic enzyme, have been measured in both cell lysates and supernatants after 24 h in culture. 6-mercaptopurine (6-MP) and azathioprine significantly decreased (P less than 0.03) the enhanced production of NAG by recruited macrophages following stimulation in vitro (total NAG activity, nmol substrate hydrolysed/microgram cell protein; recruited macrophages exposed to endotoxin, no drug exposure 0.63 +/- 0.08, azathioprine 0.44 +/- 0.08, 6MP 0.36 +/- 0.06). Prednisolone, azathioprine and 6MP significantly reduced (P less than 0.05) the supernatant release of PA in response to endotoxin exposure in vitro by both cell types (supernatant PA values after 24 h in culture, recruited macrophages exposed to endotoxin, no drug 26.0 +/- 2.9 units, prednisolone 18.5 +/- 1.7 units, levamisole 27.3 +/- 4.7 units, azathioprine 18.1 +/- 2.3 units, 6MP 17.3 +/- 1.5 units). The results from this study indicate that certain drugs used in human liver disease are able to modify the secretory activity of rat hepatic macrophages.

The effect of omeprazole on insulin induced gastric secretion in man

The effect of oral omeprazole on insulin induced gastric secretion was studied in 12 healthy subjects. Each subject participated in two secretory tests receiving an intravenous infusion of insulin (0.03 units/kg/h) and being randomly allocated to receive 30mg or 60mg omeprazole suspended in 100ml water containing 16 mmol NaHCO3 on the second study day. Peak plasma concentrations of omeprazole were achieved within 30 minutes of administration in all but one subject and plasma half life was 30 minutes. Mean peak stimulated acid output in the six subjects receiving 30mg omeprazole was reduced to 4.3 +/- S.E. 1.8 mmol/h from a control value of 16.8 +/- 2.2 mmol/h (p less than 0.05) and in six subjects receiving 60mg omeprazole, mean peak output fell to 3.4 +/- 2.1 mmol/h from a control value of 12.3 +/- 2.6 mmol/h (p less than 0.05). The two doses of omeprazole produced similar reduction in acid secretion (74% and 73% respectively) but neither dose affected pepsin secretion. Both doses of omeprazole were associated with a small statistically insignificant increase in the plasma gastrin response to insulin infusion.

An investigation into the validity of the present classification of inflammatory bowel disease

To assess the validity of the present subdivision of patients with inflammatory bowel disease into those with Crohn's disease of the small bowel or of the colon and those with ulcerative colitis, 252 patients with inflammatory bowel disease have been studied by questionnaire and case note review. One hundred and seventy-two variables concerning the nature and frequency of symptoms in remission and relapse, the incidence of complications and results of investigation have been analysed by computer. As expected, there were many highly significant variables between patients with ulcerative colitis and those with Crohn's disease of the small bowel. The latter showed evidence of a more severe disease course with more complications. There were similar, although less marked, differences between patients with Crohn's disease of the colon and those with Crohn's disease of the small bowel. There were very few differences in disease course between patients with Crohn's disease of the colon and those with ulcerative colitis. The results suggest that while separate classification of patients with Crohn's disease of the small bowel is justified on clinical grounds, the present separation of patients with disease confined to the colon into groups labelled ulcerative colitis or Crohn's disease of the colon is not. Alternative methods of classification should therefore be investigated.

Mortality of hepatitis B positive blood donors in England and Wales

Of 2880 men and 1054 women who were found to be hepatitis B surface antigen positive by the Blood Transfusion Service in England and Wales between 1971 and 1981, more than 92% were traced to the end of 1983. 5 deaths from hepatocellular carcinoma had been reported in men, giving a relative risk compared with the male population of England and Wales as a whole of 42. There had been no deaths from liver cancer in women. In both men and women there was a greater than ten-fold increase in the risk of death from chronic liver disease. Secondary preventive action may be indicated.

Magnetic resonance imaging of the Dandy-Walker malformation

Five cases of the Dandy-Walker malformation are described using the magnetic resonance (MR) scan as a primary imaging technique. The patients' ages ranged from 34 weeks (in utero) to 41 years; their clinical and neuroanatomical characteristics encompassed the entire spectrum of the malformation. Clear visualization of the greatly enlarged posterior fossa, Dandy-Walker cyst, and absence of the inferior vermis established the pathological diagnosis and excluded other structural defects. In 3 patients, MR demonstration of the aqueduct and evidence of pressure on adjacent tissue aided in the surgical planning for ventricular decompression. The MR scan is a significant advancement in the radiological diagnosis of the Dandy-Walker malformation. The major technical advantage of the scan consists in its ability to delineate intracranial morphology in multiple planes.

Pharmacology of propranolol in patients with cirrhosis and portal hypertension

Ten patients with cirrhosis and protal hypertension received an initial 20 mg oral test dose of propranolol and subsequently 160 mg of a slow release preparation, orally, each day for seven days. Protein binding, serial plasma propranolol concentrations and effects on heart rate were studied. Protein binding was slightly reduced (mean 85%, range 78.9-88.1%) compared with four normals (mean 87.9%). In patients with severe liver disease (serum albumin less than 30 g/l) propranolol remained detectable in plasma 24 hours after the single 20 mg dose and high steady state concentrations (mean 266.5 ng/ml, range 84-406) were observed during regular dosing. At steady state there was a significant correlation between log total plasma propranolol concentrations and the percentage fall in heart rate (r = 0.659, p less than 0.05). We suggest that in patients with severe liver chronic disease (serum albumin less than 30 g/l), propranolol therapy should be initiated in hospital. The starting dose should be low (20 mg of the conventional formulation tds or 80 mg of the slow release preparation daily) and that regular monitoring of the heart rate should be carried out.