In vivo histamine voltammetry in the mouse premammillary nucleus

Histamine plays a major role in the mediation of allergic reactions such as peripheral inflammation. This classical monoamine is also a neurotransmitter involved in the central nervous system but its role in this context is poorly understood. Studying histamine neurotransmission is important due to its implications in many neurological disorders. The sensitivity, selectivity and high temporal resolution of fast scan cyclic voltammetry (FSCV) offer many advantages for studying electroactive neurotransmitters. Histamine has previously been studied with FSCV; however, the lack of a robust Faradaic electrochemical signal makes it difficult to selectively identify histamine in complex media, as found in vivo. In this work, we optimize an electrochemical waveform that provides a stimulation-locked and unique electrochemical signal towards histamine. We describe in vitro waveform optimization and a novel in vivo physiological model for stimulating histamine release in the mouse premammillary nucleus via stimulation of the medial forebrain bundle. We demonstrate that a robust signal can be used to effectively identify histamine and characterize its in vivo kinetics.

Intrinsic and inducible resistance to hydrogen peroxide in Bifidobacterium species

Interest in, and use of, bifidobacteria as a probiotic delivered in functional foods has increased dramatically in recent years. As a result of their anaerobic nature, oxidative stress can pose a major challenge to maintaining viability of bifidobacteria during functional food storage. To better understand the oxidative stress response in two industrially important bifidobacteria species, we examined the response of three strains of B. longum and three strains of B. animalis subsp. lactis to hydrogen peroxide (H₂O₂). Each strain was exposed to a range of H₂O₂ concentrations (0-10 mM) to evaluate and compare intrinsic resistance to H₂O₂. Next, strains were tested for the presence of an inducible oxidative stress response by exposure to a sublethal H₂O₂ concentration for 20 or 60 min followed by challenge at a lethal H₂O₂ concentration. Results showed B. longum subsp. infantis ATCC 15697 had the highest level of intrinsic H₂O₂ resistance of all strains tested and B. animalis subsp. lactis BL-04 had the highest resistance among B. lactis strains. Inducible H₂O₂ resistance was detected in four strains, B. longum NCC2705, B. longum D2957, B. lactis RH-1, and B. lactis BL-04. Other strains showed either no difference or increased sensitivity to H₂O₂ after induction treatments. These data indicate that intrinsic and inducible resistance to hydrogen peroxide is strain specific in B. longum and B. lactis and suggest that for some strains, sublethal H₂O₂ treatments might help increase cell resistance to oxidative damage during production and storage of probiotic-containing foods.

Evaluation of the triangular cord sign in the diagnosis of biliary atresia

BACKGROUND

Infantile cholestasis continues to represent a diagnostic challenge. It is very important to diagnose surgically correctable disorders, such as biliary atresia, in a timely manner to prevent progressive damage to the liver. It has been recently suggested that the triangular cord (TC) sign is a simple and useful tool in the diagnosis of biliary atresia.

METHODS

We prospectively studied 65 infants presenting with conjugated hyperbilirubinemia (age range: 32-161 days). All patients underwent ultrasonographic examination with a 7.0-MHz transducer (Acuson, Mountain View, CA). The TC was defined as a triangular, or tubular, echogenic density seen immediately cranial to the portal vein bifurcation.

RESULTS

The TC sign was identified in 25 infants, and all of them had histologic features suggestive of biliary atresia; the diagnosis was confirmed at surgery by gross morphology of hepatobiliary system, and liver biopsy, with or without intraoperative cholangiogram. Among the 40 patients who did not have the TC sign, 6 had paucity of the intrahepatic bile ducts. Three had alph-1-antitrypsin deficiency, and 31 had neonatal hepatitis. None of the 40 patients who did not have the TC sign developed acholic stools. Seven patients with biliary atresia were followed by ultrasonographic examination for 6 months after the Kasai procedure. The TC sign disappeared in all patients after the surgery; however, the TC sign reappeared in 3 patients who developed progressive cholestasis after the procedure.

CONCLUSION

The TC sign is a simple, timesaving, and reliable diagnostic tool in the evaluation of infants with infantile cholestasis. The TC sign may also prove to be helpful in following patients after hepatoportoenterostomy. We suggest a new diagnostic strategy for patients suspected to have biliary atresia. When the TC sign is visualized, the patient should undergo intraoperative cholangiogram to confirm the diagnosis of biliary atresia, reserving percutaneous liver biopsy for those patients in whom the TC sign could not be detected.

The importance of the perfusion index in the evaluation of captopril renography for transplant renal artery stenosis

Severe renal artery stenosis (RAS) is a relatively uncommon complication following renal transplantation but is a curable cause of hypertension which demands reliable early diagnosis to reduce morbidity, mortality and graft loss. Captopril renography has been used for a number of years as a method of detecting RAS mainly in native kidneys, with only a few studies concerning the transplant situation. Controversy still exists as to the diagnostic accuracy of this test and as to the most appropriate interpretation criteria with which to establish a positive result. This paper reports the evaluation of 26 captopril renography investigations on hypertensive renal transplant patients with a suspected diagnosis of RAS. Each renogram study was correlated with an arteriogram as the 'gold standard' which was undertaken within 28 days of the renography. A sensitivity of 92%, a specificity of 86% and an accuracy of 88% were achieved by including a consideration of the change in perfusion to the kidney between pre- and post-challenge studies. It is concluded that captopril renography is a useful screening test for the detection of transplant renal artery stenosis (TRAS).

[Comparative effectiveness of class I anti-arrhythmia drugs and the algorithms of their selection in patients with ventricular arrhythmia]

The efficacy of 7 well-known Class I antiarrhythmic agents were retrospectively and by+crossover compared in 2 groups of patients treated in hospital in different years for ventricular arrhythmias. Class IC agents proved to be the most potent in the two groups of patients. The following algorithm is proposed to choose Class I agents: if quinidine or mexiletine is beneficial in the same patients, the other drugs will be also effective. If disopyramide fails to be beneficial, allapinin , ethacizine , propaphenon will be the most effective. When allapinin produces effects, ethacizine and propaphenon show their highest potency, but when each of them fails, a combination of antiarrhythmic agents should be used.

Immunogenetic study of the response to streptococcal carbohydrate antigen of the cell wall in rheumatic fever

An immunogenetic study of the response to streptococcal carbohydrate antigen of the cell wall was carried out on members of 15 multiplex families each having more than one sib affected with rheumatic heart disease. They comprised 30 parents and 61 sibs (32 with rheumatic disease and 29 without). Fifty healthy unrelated subjects served as controls. A history was taken and clinical examination carried out. Rheumatic activity was determined and HLA typing was carried out for nine A antigens, 15 B antigens, and six DR antigens. The immune response of lymphocytes to streptococcal polysaccharide antigen of the cell wall of group A beta haemolytic streptococci in vitro was studied by tritiated thymidine uptake. The results were statistically and genetically analysed. It was found that (a) all subjects with rheumatic disease were highly responsive to the streptococcal polysaccharide antigen of the cell wall, the sib pairs being mostly HLA identical; (b) all low responders had no rheumatic disease and their phenotypes were mostly different from those of the rheumatic member of their sib pair; (c) correlation of immune responsiveness (high or low) between HLA-identical sibs was significant, but insignificant between haplotype identical and non-identical sibs; (d) the gene responsible for high responsiveness to the streptococcal polysaccharide antigen of the cell wall is recessive and closely linked to HLA. In conclusion, it was found that exposure to pharyngeal infection with group A beta haemolytic streptococci may lead to acute rheumatic fever in those with an inherited recessive gene responsible for high responsiveness to the streptococcal polysaccharide antigen of the cell wall.

[Anti-arrhythmia effect of prolecophen in patients with extrasystole in comparison with other anti-arrhythmia drugs]

Oral prolecohen (LEK, Yugoslavia) was given in a single dose of 300 mg to 15 patients with extrasystole of various genesis. The drug produced an antiarrhythmic effect in 50% of patients with ventricular extrasystole, but in those with supraventricular extrasystole. Prolecophenum showed a good tolerance. In 20% of the patients the adverse reactions appeared as mild headache, dizziness, dry mouth, malaise in the epigastric region. There is also evidence for efficacy of other antiarrhythmic agents used in this group of patients.

[Pharmacodynamics of allapinin and its possible adverse effects]

Allapinine (Class IC), a new antiarrhythmic agent, was studied in 76 patients with premature contraction. Allapinine was found to be beneficial both in ventricular and supraventricular premature beats. Oral allapinine usually showed its effect 40-60 minutes following its administration, its maximum action being 4-5 hours later, its duration was some 8 hours. The optimal dose of the drug amounted to 75 mg/day. Larger-dose allapinine produced adverse effects, its lower dosage had no antiarrhythmic effect. The drug failed to affect blood pressure, heart rate, QT interval length. The PQ interval and QRS complex were increased. The side effects were dose-dependent. There was a risk of the drug's arrhythmogenic effect.

[Safety of long-term therapy with a combination of various anti-arrhythmia agents]

Safety and the effectiveness of combined therapy of arrhythmia was studied in 27 patients in prolonged (up to 4 months) administration of a combination of medicinal agents specially chosen during pharmacodynamic investigation. The obtained anti-arrhythmic effect was stable and there were no new side effects in prolonged administration of combinations of ethmozine with chinidin, ritmilen, obsidan, cordaron (amiodaron) and of allapinin with chinidin, ritmilen (disopyramide) and obsidan (propronalol). Tolerance to drugs was adequate and the ECG parameters remained unaffected.

[Pharmacokinetics and pharmacodynamics of the new Russian anti-arrhythmia drug allapinin]

Pharmacokinetics of allapinin tablets, used as a single dose, alone or in combination with other antiarrhythmic drugs (cordarone, mexitil, ritmilen) were assessed in 11 patients with frequent extrasystoles. Allapinin pharmacokinetic pattern was basically similar in patients in whom it was very effective and those in whom it had no effect. Combined use of the above-mentioned antiarrhythmic drugs and allapinin did not affect the latter's pharmacokinetic parameters. Allapinin pharmacokinetics can be described using a one-part model.

[The pharmacokinetics and pharmacodynamics of the new Soviet anti-arrhythmia preparation allapinin]

Pharmacokinetics and pharmacodynamics of a new antiarrhythmic drug allapinin was studied in patients with frequent ventricular and supraventricular extrasystoles. The technique of determining allapinin by high performance liquid chromatography is described. Intravenous administration of the drug in a dose of 20 mg was shown to be effective in 50% of patients.

Studies of peripheral blood T lymphocytes in assessment of disease activity in rheumatic fever

The study included three groups of children: (a) 38 with active rheumatic fever (ARF) and active carditis; 21 seen during their first attack and 17 during recurrence of activity, (b) 47 with inactive rheumatic fever (IARF); the period since activity was less than 3 years in 31 cases and more than 3 years in 16 cases. Using monoclonal antibodies and T lymphocyte blast transformation induced by PHA, we found: (1) low total T lymphocytes, helper-inducer cells and helper-inducer/suppressor-cytotoxic ratio which persisted for years; and (2) reduced lymphoblast transformation in active disease.

Immune regulation dysfunction in chronic persistent hepatitis

The study included 19 children diagnosed clinically, biochemically, and by liver biopsy as having chronic persistent hepatitis. The following investigations were carried out: 1. detection of total T-lymphocytes, T-helper, and T-suppressor cells using monoclonal antibodies (OKT3, OKT4 and OKT8); 2. determination of HLA-A, B and DR antigens using the microcytotoxicity technique. The results were analysed in comparison with data from a normal control group. There are several important findings. First, low total T-lymphocytes with increased proportion of suppressor cells (P less than 0.001). Second, strong association between HLA-A1 antigen and CPH (Fisher exact = 0.000022). Third, significant association between the immunoregulatory dysfunction and A1 antigen (Fisher exact = 0.033). This observation suggests that a genetic component may influence susceptibility to CPH through an increased suppressor response.