Immunological Changes and Liver Disease Associated with α1-Antitrypsin Deficiency

Summary: Immunological changes and liver disease associated with alpha-1 -antitrypsin deficiency.
A female aged 60 years with heterozygous alpha-1-antitrypsin deficiency developed a progressive and ultimately fatal liver disease with the clinical, biochemical, immunological and histological characteristics of active chronic hepatitis. It is suggested that the hepatic disease of A-AT deficiency be included among the types of liver disease which may initiate a progressive immuno-pathic response.     

Alpha1-Adrenergic Blockade and Sudden Cardiac Death

Alpha₁-Adrenergic Blockade and Sudden Cardiac Death. Introduction: The primary goal of the present study was to test whether selective pharmacologic blockade of alpha₁ receptors, and specifically of the subtype alpha_1a could prevent ventricular fibrillation (VF) during acute myocardial ischemia. Background: The development of new autonomic interventions is of clinical interest in view of the failure of traditional; antiarrhythmic drugs to prevent sudden death. Experimental evidence indicates that alpha, receptors, and in particular the subtype alpha_1a may he involved in the genesis of malignant arrhythmias during acute myocardial ischemia and reperfusion. Despite this evidence, questions have been raised about the actual antifibrillatorv efficacy of alpha-adrenergic blockade in the acutely ischemic myocardium. The effects of prazosin and of abanoquil (UK 52,046), a highly selective alpha_1a receptor blocker, were tested and compared with propranolol in a conscious animal preparation for sudden death. Methods and Results: Ten dogs with a 1-month-old anterior wall myocardial infarction were studied. These dogs had all developed, in control conditions, VF during a 2-minute occlusion of the circumflex coronary artery while exercising (n=9) or lying on the table (n=1). Afterwards, the dogs underwent additional tests with the following intravenously administered drugs: abanoquil (n=10; 1μg/kg. prazosin (n=9; 0.1 mg/kg), and propranolol (n=10; 1 mg/kg). Internal control analysis was used. All dogs tested had recurrence of VF with both alpha-adrenergic blockers. Propranolol significantly reduced heart rate during ischemia and prevented VF in 5 of 10 dogs tested (P < 0.05). When heart rate was kept constant by atrial pacing (n = 3), 2 of the 3 animals remained protected by propranolol. Just prior to onset of VF, heart rate was not significantly different in the control and in the abanoquil tests (237 ± 45 and 253 ± 34 beats/min, respectively), whereas it was higher (P < 0.05) with prazosin (288 ± 40 beats/min). Conclusions: Alpha, and alpha_1a receptor blockers do not prevent VF secondary to acute myocardial ischemia in the presence of elevated sympathetic activity and heart rate. In the same setting, beta-adrenergic blockade prevents the reflex heart rate increase due to ischemia and provides a significant protection.     

Alpha1-Adrenergic Receptor Modulation of Repolarization in Canine Purkinje Fibers

Alpha-Agonists and Repolarization. Introduction: Alpha-adrenergic receptor stimulation increases contractility and prolongs repolarization. These effects are modulated by α₁-adrenergic receptor-mediated inhibition of transsarcolemmal potassium currents.
Methods and Results: We used standard microelectrode techniques to study the actions of 4-aminopyridine (4-AP), which blocks the transient outward current, I_to, and WAY-123,398, which blocks the delayed rectifier, I_k, on canine Purkinje fiber action potential prolongation induced by phenylephrine. At a basic cycle length of 1 second, phenylephrine (0.1 to 10 μ) dose-dependently prolonged action potential duration at 90% repolarization (APD₉₀) from 331 ± 10 msec to 400 ± 12 msec (P < 0.05) at phenylephrine, 10 μ. Phenylephrine did not change phase 1 or plateau height. 4-AP (0.1 mM) decreased phase 1 magnitude, shifted plateau height to more positive potentials (from 0.1 ± 1.8 mV to 14.3 ± 1.1 mV [P < 0.05]), and shortened APD₉₀ from 318 ± 9 msec to 294 ± 8 msec (P < 0.05). 4-AP did not block phenylephrine effects on APD₉₀, which increased, at 10 μ phenylephrine, from 294 ± 8 msec to 342 ± 6 msec (P < 0.05). In contrast, WAY-123,398 (0.1 μ) prolonged APD₉₀ from 360 ± 6 msec to 452 ± 6 msec (P < 0.05), and had no effect on plateau height. In the presence of WAY-123,398, phenylephrine no longer increased APD_9o.
Conclusion: (1) Agents that block I_to shorten APD in Purkinje fibers; and (2) the α-agonist mediated increase of APD in canine Purkinje fibers can be explained by inhibition of I_k.     

Preparation and Properties of Alpha1-Proteinase Inhibitor Concentrate from Human Plasma

Alpha 1-proteinase inhibitor (alpha 1-PI) has been prepared as a concentrate in quantities large enough for clinical testing of its safety and efficacy in the treatment of emphysema and other disorders. The alpha 1-PI was purified from Cohn fraction IV-1 paste by polyethylene glycol precipitation and DEAE-Sepharose chromatography. The methods used in the purification are gentle and the resulting product behaves almost identically to the alpha 1-PI from plasma. The protein has been heat treated (60 degrees C, 10 h) to lower the risk of transmission of plasma-borne diseases. This resulted in some aggregation of the protein, but did not cause the generation of new antigenic sites. Half-life studies in animals showed that the protein behaved normally (catabolic t1/2 of 68 h).     

α1-Antitrypsin phenotypes in chronic active hepatitis

Abstract α₁-Antitrypsin (Pi) phenotypes were determined in 58 Caucasian patients with chronic active hepatitis, in whom there was no evidence for a specific aetiological factor. Pi allele and gene frequencies were compared with frequencies in 1007 Australian Caucasian blood donors. There was an increased frequency of the M1M3 phenotype in chronic active hepatitis patients. In contrast to other studies, there was no increase in the frequency of the MZ phenotype. The chronic hepatitis patients had a gene frequency of 0.034 for Pi Z, compared to 0.012 in blood donors. The difference is not statistically significant. The Pi Z group consisted of one homozygous Pi Z patient, previously diagnosed as having chronic active hepatitis and cirrhosis due to α¹-antitrypsin deficiency, and only two heterozygous Pi Z subjects. This study fails to confirm a major association between chronic active hepatitis and heterozygous Pi Z phenotypes.     

Biochemical and Biological Properties of an α1-Antitrypsin Concentrate

alpha 1-Antitrypsin (AAT) has been purified from human plasma supernatant A (equivalent to COHN fraction II + III) by a large-scale chromatographic procedure involving anion-exchange adsorption on DEAE Sepharose CL-6B fast flow and size-exclusion chromatography on Sephacryl S-200. Before freeze-drying, the liquid concentrate was heat-treated at 60 degrees C for 10 h to reduce the risk of transmission of blood-born viral diseases. Using this procedure, AAT is recovered with 80-90% purity in 65-75% yield from supernatant A. The heterogeneity of AAT is preserved across the purification steps. In addition, purified AAT exhibits inhibitory activities against trypsin and elastase equivalent to that of the serum protein. The mean association rate constant for elastase was found as high as 2.15 X 10(5) M-1 s-1. Thus, purifying active AAT from supernatant A contributes to improving the availability of this protein which may be potentially useful in the treatment of hereditary emphysema.     

REVIEW: α1-Antitrypsin deficiency associated liver disease

α₁-Antitrypsin (α₁-AT) deficiency is the most common genetic cause of liver disease in children and genetic disease for which children undergo liver transplantation. It also causes cirrhosis and hepatocellular carcinoma in adults. Studies by Sveger in Sweden have shown that only a subgroup of the population with homozygous PiZZ α₁-AT deficiency develop clinically significant liver injury. Other studies have shown that the mutant α₁-AT Z molecule undergoes polymerization in the endoplasmic reticulum and that a subpopulation of α₁-AT-deficient individuals may be susceptible to liver injury because they also have a trait that reduces the efficiency by which the mutant α₁-AT Z molecule is degraded in the endoplasmic reticulum.     

Primary Liver Cancer, Alpha1 Fetoprotein and Hepatitis B Antigen in Papua New Guinea

Summary: Sera from 72 Papua New Guinean patients with hepatocellular carcinoma were tested for alpha₁ fetoprotein, hepatitis B antigen and antibody by sensitive techniques including radio-immunoassay. Alpha₁ fetoprotein was detected in 98% of samples and Hepatitis B antigen in 82%. Hepatitis B antibody was present in only 2.8% of samples. The implications of these findings are considered.     

Homozygous deletional α+ thalassaemia associated with unequal expression of the two remaining α1 genes (α1A and α1Q)

S ummary . A Cambodian family presenting several haemoglobinopathies, Hb E, Hb Q and α⁺ thalassaemia, has been investigated. DNA analysis showed that the thalassaemia syndrome corresponds to a leftward type (4.2 kb) deletional from of α⁺ thalassaemia. Genotypes found in the family are: propositus -α^A/-α^Q, β^A/β^E, mother and older sister α^Aα^A/ -α^Q, β^A/β^E; father α^Aα^A/-α^A, β^A/β^A. The propositus consistently presents an α^Q/α^A chain ratio of 60/40 although both chains are products of α₁ loci. The relatively higher expression of the α^Q chain is not observed in the mother and therefore makes it unlikely to reflect anything other than differential expression of the maternal -α^Q/ and paternal -α^A/ haplotypes. This observation raises the possibility that both haplotypes are not strictly identical and that the region of the cross-over event is important for α gene expression.     

Development of a monoclonal antibody capable of differentiating platelet PLA1/PLA1, PLA1/PLA2 and PLA2/PLA2 genotypes

A monoclonal antibody, LK-4, has been developed which distinguishes platelet PLA1/PLA1, PLA1/PLA2 and PLA2/PLA2 genotypes on platelet glycoprotein GPIIIa of Triton-solubilized platelet extracts. An ELISA assay has been developed which traps GPIIIa with Concanavalin A, enriching the platelet extract for the PLA antigens. A second monoclonal antibody, DEK-10, which reacts equally with GPIIIa of PLA1/PLA1 and PLA2/PLA2 platelet extracts is employed as an internal standard to correct for individual differences in GPIIIa content, GPIIIa extracted by Triton X-100 and GPIIIa trapped with Concanavalin A. This ELISA assay clearly differentiated 11 different PLA1/PLA1 subjects from eight PLA2/PLA2 women with a history of neonatal alloimmune thrombocytopenia as well as six unrelated obligate heterozygotes and should be useful in evaluating the PLA genotype of pregnant women and their families.     

Reversible C3 Hypocomplementaemia in Megaloblastic Anaemia due to Vitamin B12 Deficiency

S ummary . Serum C3 and C4 levels have been determined in patients with Addisonian pernicious anaemia (PA) and megaloblastic anaemia due to vitamin B₁₂ deficiency from other causes, before and after treatment, in order to study the interaction between vitamin B₁₂ deficiency and Complement and the role of complement in the pathogenesis of the gastric lesion of PA. C₃ levels are significantly reduced in vitamin B₁₂ deficiency and return to normal on treatment; C₃ levels correlate with the degree of anaemia but not with serum vitamin B₁₂ levels at diagnosis. C₄ levels are normal. These observations suggest that the observed C₃ hypocomplementaenlia is not a consequence of immune mechanisms, but may be due to altered synthesis of C₃ complement component.     

Dose-Dependent Destruction of A1 Cells by Anti-A1

Abstract. In a patient of subgroup A₂ the serum contained an unusually potent anti-A₁, giving the following reactions with A₁ red cells in vitro: agglutination of saline-suspended cells up to a temperature of 32°C; a positive indirect antiglobulin test (complement only) at 37°C and lysis of enzyme-treated cells at 37°C. A series of tests was carried out to estimate the ability of the antibody to destroy varying amounts of A₁ red cells in vivo . When about 0.55 ml of red cells was injected, about 65% of the cells were destroyed within 30 min; 2 days later when 18.9 ml of cells were injected, only about 45% were destroyed within 30 min; 5 days after this when a whole unit of A₁ red cells was transfused, survival at 24 h was about 90%. This last figure may indicate that destruction of red cells by anti-A₁ was negligible since at the time of the transfusion of the whole unit the patient was bleeding into her gastrointestinal tract. On the other hand, the titre of anti-A₁ appeared to be declining spontaneously during the period in which tests were carried out so that, if the whole unit of A₁ blood had been transfused at the beginning of this period, survival might have been less good. Nevertheless, from the observed difference in survival between the 0.55 ml and 18.9 ml doses it seems safe to conclude that, even if the unit had been transfused at the time when the antibody concentration was maximal, the percentage of cells destroyed would have been small.     

Anti-A1 Leb in Serum of a Person of a Blood Group A1h

Abstract. An antibody, anti-A₁ Le^b, has been found in the serum of a person belonging to group A₁h, with complete depression of H on the red cells as well as in the saliva. It differs from earlier examples of the antibody in that it can be neutralized by A₁ nL, secretor saliva as well as O Le^b secretor saliva in addition to A₁ Le^b secretor saliva. Although the proposita secretes A substance, she only secretes Le^a substance and not Le^b substance. No such abnormalities were found in the family investigated. An interpretation of the case is given according to the classical hypothesis of ABO and Lewis system development.     

Ph1-positive and Ph1-negative abnormal cell lines in a child with lymphoblastic lymphoma

A 7-year-old Japanese boy with Ph1-positive-lymphoblastic lymphoma is described. The diagnosis was based on biopsied tonsils which were enlarged at the time of admission. On the eighth day after admission an enlarged mediastinal mass was detected on a chest X-ray film. The lymphoblasts which appeared in the peripheral blood and bone marrow proved to be T-cells. Chromosome studies on the bone marrow cells revealed two abnormal cell lines; one had a 7;11 translocation and the other a 7;11 translocation and a 9;22 translocation, forming the Ph1-chromosome. The latter line with the Ph1-chromosome was considered to have been derived from the former line without the Ph1. Our findings show that the Ph1-chromosome may be a secondary change in the course of karyotypic evolution.