A pore-forming toxin produced by Aeromonas sobria activates Ca2+ dependent Cl- secretion

Bacteria produce many types of hemolysin that induce diarrhea by mechanisms that are not completely understood. Aeromonas sobria hemolysin (ASH) is a major virulence factor produced by A. sobria, a human pathogen that causes diarrhea. Since epithelial cells in the intestine are the primary targets of hemolysin, we investigated the effects of ASH on ion transport in human colonic epithelial (Caco-2) cells. ASH increased short-circuit currents (Isc) in a dose-dependent manner, and it also activated a 125I efflux from Caco-2 cells. ASH-induced Isc increases and 125I efflux activations were both suppressed by low Ca2+ levels in the extracellular solution or by pretreatment with the Ca2+ chlelator BAPTA-AM. Intracellular Ca2+ levels were increased by ASH in a biphasic fashion characterized by a rapid sharp increase (peak 1) followed by a sustained low plateau (peak 2). ASH-induced peak 1 was inhibited by pretreatment with pertussis toxin, indicating that Ca2+ was mobilized from intracellular stores, and peak 2 was induced by an influx of extracellular Ca2+. Peak 2 but not peak 1 was related to Cl- secretion. These results indicate that ASH activates Ca2+-dependent Cl- secretion.     

Expression of estrogen receptor alpha (ER alpha) in the rat temporomandibular joint

Numerous epidemiological studies have pointed out a higher frequency of temporomandibular disorder (TMD) in women than in men, which indicates the involvement of a sex hormone, such as estrogen, in the pathogenesis of TMD. Although estrogen is known to play pivotal roles in osteoarthrosis or rheumatoid arthritis in systemic joints, there have been few reports about the role of estrogen in the temporomandibular joint (TMJ). The effect of estrogen is generally mediated by the estrogen receptors (ERs) ER alpha (the predominant type) and ER beta. In this study we examined the expression of ER alpha protein and mRNA in the TMJ of adult male rats by immunocytochemistry and in situ hybridization histochemistry. Intense ER alpha immunoreactivity was localized in the synovial lining cells, stromal cells in the articular disc, and chondrocytes in the TMJ. These ER alpha-immunopositive synovial lining cells are characteristic of cytoplasmic processes identified with confocal and immunoelectron microscopy, which indicates that they are synovial type B cells. In situ hybridization histochemistry confirmed intense signals for ER alpha in the synovial lining cells and the sublining fibroblasts at mRNA levels. The nuclei of chondrocytes showed an intense immunoreaction for ER alpha in the maturative and hypertrophic layers of the articular cartilage. In addition to the nuclear localization of ER alpha, a weak immunoreaction appeared in the cytoplasm of some ER alpha-positive cells. These findings support the hypothesis that TMJ tissue-at least in the male rat-has the potential to be an estrogen target tissue.     

The earliest stages of B cell development require a chemokine stromal cell-derived factor/pre-B cell growth-stimulating factor

Environmental factors essential for the first stages of B lymphopoiesis remain elusive. Here, we report that immediately after commitment to B lineage, precursors become dependent on a chemokine SDF-1 and its receptor CXCR4 using mutant and radiation chimeric mice. In bone marrow, generation of the earliest identifiable B cell precursor populations requires CXCR4. In fetal liver, we identified Lin(-)CD19(-)c-kit(+)IL-7Ralpha(+)AA4.1(+), the earliest unipotent B cell precursor population, and found that its development was severely affected in SDF-1(-/-) embryos but not in IL-7(-/-) embryos. Lin(-) T cell progenitors appeared normal in SDF-1(-/-) embryos. Moreover, SDF-1 exhibited specific biologic activities on the earliest B cell precursors. SDF-1 provides the first example of a cytokine responsible for the earliest B lineage stages.     

A method for simultaneous recording of electrical activities and spectrophotometric signals from brain slice preparations in vitro

Organ spectrophotometry has been applied to analyze cytochrome redox changes in brain slice preparations. An interface-chamber method for maintaining metabolism of brain slice tissues was devised to reduce noise on recording traces of spectrophotometric signals, and then used for continuous monitoring and simultaneous recording of electrical and optical signals from brain slices. With this method, the noise level during the recording of redox states of cytochromes was decreased to 0.0004 A unit.     

A unique localization of mechanoreceptors in the periodontal tissue of guinea pig teeth

This study describes the unique distribution of Ruffini endings (RE) in the periodontal tissues of the guinea pig teeth with special references to their presence in the enamel-related aspects of the continuously growing incisors and molars. In guinea pig incisors, immunohistochemistry for PGP 9.5 and glia specific S-100 protein revealed a condensed distribution of well-developed RE in the bone-related part of the lingual periodontal ligament as has been reported in many other rodents. In most cases, some RE-like nerve elements characterized by dendritic ramification and rounded terminal Schwann cells were found to be located in the labial, enamel-related regions, where no periodontal ligament-like fiber arrangement was established. In the molar periodontal ligament, well-developed RE-like nerve elements were also distributed in the enamel-related part, but in intimate relation to thick periodontal fiber bundles inserted in the cementum pearls grown on the enamel surface. In some cases, few RE were located in the apical region of the alveolar socket, where no periodontal fiber bundles could be identified. Our data provide the first morphological evidence of the presence of RE-like nerve elements in the enamel-related, fibrous connective tissue of continuously erupting rodent incisors. These data indicate that RE in guinea pig periodontal tissues have variable spatial correlation to the surrounding fibers, implicating their diverse mechanoreceptive properties depending on the anatomical location.     

Pyothorax-associated lymphoma: an unusual case with both T- and B-cell genotypes

Pyothorax-associated lymphoma (PAL) is a B-cell lymphoma which develops in the pleural cavity of patients with an over-20-year history of pyothorax. Aberrant expression of surface antigens is occassional in PAL, although genotype is not fully investigated. We report here a PAL with dual genotype, i.e., simultaneous immunoglobin (Ig) and T-cell receptor (TcR) gene rearrangement. An 82-year-old woman with pain on the left side of the chest was admitted. She had been suffering from pyothorax after artificial pneumothorax for treatment of tuberculosis of the pulmonary when she was 18 years old. The mass that was confined to the left pleural cavity affected by pyothorax was biopsied and histologically diagnosed as diffuse large cell lymphoma. The tumor cells were positive for CD20, CD16, and TIA-1 but negative for CD79a, CD45RO, CD43, CD3, and CD56. Surface antigen expression was further investigated in cultured cells, showing that the cultured cells did not express representative B-cell markers, except for CD20, as well as T-cell markers, but were positive for CD16, CD30, and CD103. Southern blotting revealed the monoclonally rearranged bands of both Ig heavy chain and TcR gene. The patients died of tumors 14 months after admission. Aberrant genotype and immunophenotype of PAL cells is discussed in reviewing the pertinent literature.     

Functional interleukin 2 receptors on B cells lacking Tac antigens

Human B lymphoblastoid line, SKW 6-4, cells were induced to IgM-secreting cells by high concentrations of interleukin 2 (IL 2). These cells were found to be unreactive with anti-Tac antibody and did not express mRNA detectable for Tac antigen. In Scatchard plot analysis, low-affinity IL 2-binding sites were found on SKW 6-4 cells. Moreover, analysis of the IL 2-binding molecules revealed ones (molecular weight 70,000 and 75,000) distinct from Tac antigen. It is conceivable that IL 2 exerts its effect through its interaction with these novel IL 2-binding molecules in SKW 6-4 cells.     

Increased protein glycation in cerebrospinal fluid of Alzheimer's disease

Accumulation of advanced glycation end products occurs in the brain with ageing and was proposed to be involved in pathogenesis of Alzheimer's disease. We studied changes in the level of an early glycation product, an Amadori product, in cerebrospinal fluid (CSF) in ageing and in late-onset Alzheimer's disease. The work was carried out on 99 consecutive patients. The concentration of Amadori product in CSF correlated with CSF glucose concentration but was not changed with age (n = 70). In contrast, level of CSF Amadori product was 1.7-fold higher in Alzheimer's disease patients (n = 29) as compared with non-demented age-matched control group (n = 20; P < 0.0005), although CSF glucose concentration was similar in both groups (4.1 +/- 1.3 vs. 3.8 +/- 0.6 mmol/liter, resp.). An increased accumulation of Amadori products was found in all major proteins of CSF of Alzheimer's disease including albumin, apolipoprotein E and transthyretin. We propose that the increased early glycation of CSF proteins in the Alzheimer's patients may stimulate the formation and the consequent deposition of advanced glycation end products as well as oxidative stress in the brain.     

A subcutaneously injected UV-inactivated SARS coronavirus vaccine elicits systemic humoral immunity in mice

The recent emergence of severe acute respiratory syndrome (SARS) was caused by a novel coronavirus, SARS-CoV. It spread rapidly to many countries and developing a SARS vaccine is now urgently required. In order to study the immunogenicity of UV-inactivated purified SARS-CoV virion as a vaccine candidate, we subcutaneously immunized mice with UV-inactivated SARS-CoV with or without an adjuvant. We chose aluminum hydroxide gel (alum) as an adjuvant, because of its long safety history for human use. We observed that the UV-inactivated SARS-CoV virion elicited a high level of humoral immunity, resulting in the generation of long-term antibody secreting and memory B cells. With the addition of alum to the vaccine formula, serum IgG production was augmented and reached a level similar to that found in hyper-immunized mice, though it was still insufficient to elicit serum IgA antibodies. Notably, the SARS-CoV virion itself was able to induce long-term antibody production even without an adjuvant. Anti-SARS-CoV antibodies elicited in mice recognized both the spike and nucleocapsid proteins of the virus and were able to neutralize the virus. Furthermore, the UV-inactivated virion induced regional lymph node T-cell proliferation and significant levels of cytokine production (IL-2, IL-4, IL-5, IFN-gamma and TNF-alpha) upon restimulation with inactivated SARS-CoV virion in vitro. Thus, a whole killed virion could serve as a candidate antigen for a SARS vaccine to elicit both humoral and cellular immunity.     

Continuous administration of gonadotrophin-releasing hormone agonist during the luteal phase in IVF

BACKGROUND: It has been reported that ceasing the administration of gonadotrophin-releasing hormone (GnRH) agonist causes a profound suppression of circulating serum gonadotrophins. A comparative prospective and randomized study was conducted to investigate the effect of continuous administration of GnRH agonist during the luteal phase in an ovarian stimulation programme for IVF. METHODS: GnRH agonist was administered intranasally from the midluteal phase of the previous cycle, and pure FSH administration started on cycle day 7. In the continuous-long protocol (cL) group (n = 161 ), GnRH agonist administration was continued until 14 days after oocyte retrieval. In the long protocol (L) group (n = 158 ), GnRH agonist was administered until the day before human chorionic gonadotrophin (HCG) administration. RESULTS: The implantation rate and live birth rate per unit of transferred embryos were significantly higher in the cL group than the L group (P < 0.05 ). Serum LH and FSH concentrations on the day of, and 1 day after, HCG administration were significantly lower in the L group than the cL group (P < 0.01 ). CONCLUSIONS: Continuation of GnRH agonist administration during the luteal phase might facilitate implantation, and prevent the profound suppression of serum gonadotrophins.