The αβ T Cell Receptor Clustering Upon Superantigen/MHC Recognition

Antigen recognition by T cells is the key event for the antigen specific immune responses to be triggered. This recognition is initiated by the binding of the T cell receptor (TCR) to antigen peptide/major histocompatibility complex (MHC) on the surface of the antigen presenting cells. TCR on most of the T cells is a heterodimer composed of α and β chains which are associated with CD3 γδε as well as ζ chains, the signal transmission molecules. The dynamics of this TCR complex upon antigen/MHC recognition, however, has not been well understood. In this paper the authors analyse the configuration of TCR complex on T cells from a TCR β chain gene transgenic mouse (TGM) strain. Unlike many other TGM strains reported, a considerable proportion of T cells from this TGM expresses both transgene-encoded (Vβ3) and endogenous TCR β chains on their surface. By immunoprecipitation and immunoblotting analysis of T cells stimulated with a superantigen, staphylococcal enterotoxin B (SEB), the authors found that Vβ3 was coprecipitated with Vβ8, demonstrating the clustering of TCR αβ upon superantigen/MHC recognition.     

Relationship between cellular ATP content and cellular functions of primary cultured rat hepatocytes in hypoxia

The importance of oxygen in maintaining the functional integrity of hepatocytes has been well established in a variety of experimental models, such as in vivo , perfused liver and isolated hepatocytes. However, one of the shortcomings of these systems is their short life span. Therefore, we have examined the effects of long-term hypoxia on cellular adenine nucleotide content and cellular functions, such as albumin production, urea production and DNA synthesis, in adult rat hepatocytes in primary culture. Hepatocytes were cultured at a density of 11 × 10⁴ and 5 × 10⁴ cells/0.18 mL per cm² for the study of albumin and urea production and DNA synthesis, respectively, at various oxygen tensions (20, 12, 8 and 5%) for 24 h. Cellular ATP content in cultured hepatocytes in hypoxia gradually declined, corresponding to the decrease in oxygen tension, and the cellular ATP level at 5% oxygen was approximately 20% of that at 20% oxygen. Albumin production also decreased in parallel with the decrease in cellular ATP content in cultured hepatocytes in hypoxia. However, even when cellular ATP content gradually declined corresponding with the decrease in oxygen tension in cultured hepatocytes in hypoxia, such as at 8 or 5% oxygen, urea production remained at a high level; in contrast, DNA synthesis was completely suppressed. These results suggest that the cellular ATP content decreases in cultured hepatocytes during long-term hypoxia in relation to oxygen tension and that the relationship between decreased ATP levels and liver function in cultured hepatocytes during hypoxia differs for albumin production, urea production and DNA synthesis.     

Production of tumour necrosis factors by human T cells stimulated by a superantigen,toxic shock syndrome toxin-1

The capacity of human T cell subsets, CD4⁺ or CD8⁺ T cells, to produce tumour necrosis factors (TNF-α and TNF-β) upon stimulation with toxic shock syndrome toxin-l (TSST-I) and the requirement for MHC ctass II molecules on accessory cells (AC) in the response were investigated. The capacity of CD4⁺ T cells was much higher than that of CD8⁺ T cells in TSST-1-induced production of TNF-α and TNF-β. The expression of MHC class II molecules on AC was required in the response.     

Lennox-Gastaut syndrome: A new vista

Abstract Lennox-Gastaut syndrome (LGS) is regarded as a model of the epileptic syndrome because of its specific clinicoelectrical manifestation. However, a close investigation reveals that its outline is somewhat vague, having the borderland around it. Precise diagnosis in an individual case is not always easy. In this paper, the diagnostic criteria of LGS are described. According to these criteria, cases with LGS were subclassified into the typical and the atypical cases, and also cases in the borderland of LGS were reviewed. On the other hand, our prospective long-term follow-up study revealed that cortical mechanisms played an important role in the pathophysiology, clinical features and refractoriness of LGS. Secondary bilateral synchrony (SBS) is supposed to be a mode of expression of cortical mechanisms of LGS. A newly developed method with coherence and phase analysis demonstrated that the pathophysiology was based on SBS in 33% of the typical LGS cases. This finding is not only crucial for the choice of rational treatment including epilepsy surgery, such as callosotomy, but also contributes to a more refined subclassification of LGS.     

New Electrophysiologic Features and Catheter Ablation of Atrioventricular and Atriofascicular Accessory Pathways:

Catheter Ablation for Mahaim Pathways. Introduction : Several modalities of catheter ablation have been proposed to eliminate Mahaim pathway conduction. However, limited research has been reported on the electrophysiologic nature of this pathway in its entity.
Methods and Results : In seven patients, electrophysiologic study was performed, and radiofrequency energy was applied to investigate the electrophysiologic clues for successful ablation. In all seven patients, the Mahaim pathway was diagnosed as a right-sided atriofascicular or atrioventricular pathway with decremental properties. In two patients, two different kinds of electrograms were recorded through the ablation catheter positioned at the Mahaim pathway location: one was suggestive of conduction over the decremental portion, demonstrating a dulled potential; and the other of nondecremental conduction, demonstrating a spiked potential. All but one of the Mahaim pathways were eliminated successfully at the atrial origin where the spiked Mahaim potential was recorded. Radiofrequency energy application was performed at the slow potential site resulting in failure to eliminate the conduction over the Mahaim pathway. Conduction block at the site between the slow and fast potential recording sites was provoked by intravenous administration of adenosine, concomitant with a decrease in the amplitude of the Mahaim potential. In one patient, the clinical arrhythmia was a sustained monomorphic ventricular tachycardia originating from the ventricular end of the Mahaim fiber.
Conclusion : The identification of Mahaim spiked potentials may be the optimal method to permit their successful ablation. Detailed electrophysiologic assessment is indispensable for successful ablation of tachycardias associated with Mahaim fibers because tachycardias unassociated with Mahaim fibers can occur despite complete elimination of the Mahaim fiber.     

Laparoscopic and Histopathologic Features of the Liver in Severe Chronic Active Epstein-Barr Virus Infection Syndrome: A Case Report

Abstract: A 40-year-old man was admitted to our hospital with persistent fever, generalized lymphadenopathy and hepatosplenoamegaly. Immunological examination demonstrated high titers of several anti-Epstein-Barr virus (EBV) antibodies, including anti-viral capsid antigens 1gG-antibody 1: 20, 480, anti-early antigens-DR IgG-antibody 1: 5, 120, and reduced activity of EBV-specific cytotoxic T lymphocytes. Laparoscopic features resembled those of chronic active viral hepatitis, including an uneven surface appearance and diffuse hepatic enlargement. Histopathological examination of a liver biopsy specimen showed inflammatory cell infiltration along sinusoidal surfaces (single file appearance) and enlarged portal areas with intralobular punched-out necrosis. The diagnosis was confirmed by detecting the EB viral genome in serum. Despite treatments with natural alpha-interferon, adenosine arabinocide and recombinant human interleukin-2, the patient died of progressive hepatic failure.     

Analysis of Fibrinolysis by the Use of Epsilon-Aminocaproic Acid: Preliminary Report

From the foregoing analysis of the inhibitory action of -aminocaproic acidin the fibrinolytic process, it is evident that the process involves two reactionphases, fibrinolysis and metafibrinolysis.

Fibrinolysopeptide and metafibrin are split off from fibrin in fibrinolysis.The former is a peptide with N-terminal glycine, while the latter is a monochloracetic acid-soluble metaprotein having both aspartic acid and tyrosineas N-terminal amino acids.

     

Transabdominal vesical sonography of urethral syndrome and stress incontinence

BACKGROUND: Transabdominal ultrasonography was used to study the bladder neck morphology in women with urethral syndrome or stress urinary incontinence, in order to determine the ultrasonographic findings of these conditions. METHODS: A total of 210 female patients with a normal bladder, asymptomatic trigonitis, urethral syndrome, and stress incontinence were studied. The mucosal thickness around the bladder neck, the length of the anterior base plate of the bladder, and the anteroposterior vesical wall angle (APVA) at the bladder neck were measured on sagittal transabdominal vesical ultrasonograms with the patient in the supine position. RESULTS: Patients with asymptomatic trigonitis or urethral syndrome had thicker mucosa around the bladder neck than the subjects with a normal bladder, and the subjects with stress incontinence had normal mucosa. The APVA was 158 +/- 17 (mean +/- SD) degrees in the subjects with a normal bladder. It was smaller in symptomatic patients and decreased to 109 +/- 10 degrees in those with conservative therapy-resistant incontinence. The anterior edge of the vesical base plate was visible approximately 2 cm from the bladder neck in subjects without incontinence, while it tended to be absent in patients with incontinence and an APVA of less than 126 degrees. CONCLUSION: A small APVA appears to reflect bladder neck descent, while a small APVA without a visible anterior base plate edge may reflect hypotonia of the vesical base plate. Transabdominal vesical ultrasonography with the patient in the supine position provides useful information and can be carried out as a routine examination in female patients with micturition disorders.     

Case Report: Interferon induced coma in Sheehan's syndrome

A 54-year-old woman who was being treated with 10 million units (mu) of natural interferon (IFN)-α per day for chronic active hepatitis C at a local clinic, developed coma on the fourth day of treatment. On admission to Yamagata University Hospital, she was still in a state of semicoma with severe hyponatraemia (122 mEq/L) and hypochloraemia (89 mEq/L). After the administration of electrolytes, her condition improved remarkably. Endocrinological loading tests showed a hypofunction of the anterior pituitary gland. In consideration of these results, and her past experiences of haemorrhage during childbirth and subsequent amenorrhoea, we diagnosed her illness as a coma as a result of Sheehan's syndrome which had become overt during IFN therapy. She recovered completely after treatment with hydrocortisone and 1-thyroxine.     

A case of urethral prolapse in a young girl

Urethral prolapse is rarely reported in the pediatric literature. We report a 4 year old female with urethral prolapse and discuss the etiology and the treatments in children documented in the literature.