Increased osteocyte apoptosis during the development of femoral head osteonecrosis in spontaneously hypertensive rats

We investigated the presence of osteocyte apoptosis in the necrotic trabeculae of the femoral head of spontaneously hypertensive rat (SHR) using the in situ nick end labeling (TUNEL) method and transmission electron microscopy. The occurrence of osteonecrosis and ossification disturbance was significantly higher in SHR compared with Wistar Kyoto (WKY) rats, and Wistar (WT) rats used as control animals (P < 0.01). A high population of TUNEL positive osteocytes was detected mainly in 10- and 15-week-old SHRs. Sectioned examination of the femoral head of SHRs and WKY rats by electron microscopy revealed apoptotic cell appearances such as aggregation of chromatin particles and lipid formation. In contrast, a positive reaction was significantly lower in osteocytes in the femoral heads of WT rats (P < 0.01). Our results indicate that apoptosis forms an important component of the global pathologic process affecting the femoral head of SHR, which leads to osteonecrosis in this region.     

Responsiveness of the ANP providing system to volume load in conscious dogs

We examined in detail changes in arterial plasma ANP concentration in response to volume load in conscious dogs. In a 5-min volume load experiment, 18 ml/kg of isosmotic and isooncotic 3% Dextran 40 in saline was infused over a period of 5 min. Mean left atrial pressure (MLAP) increased transiently by 7.6±0.9 mm Hg. Plasma ANP level (P-ANP) did not significantly increase. Assayed P-ANP levels were corrected for hemodilution. Corrected P-ANP (C-ANP) significantly increased from 206±17 to 348±34 pg/ml. However, the level of C-ANP did not reach a steady state. No significant linear correlation was found between increases in MLAP and normalized C-ANP. In a 45-min volume load experiment, the elevated level of MLAP caused by the 5-min volume load was maintained for 40 min by supplemental infusion. C-ANP significantly increased from 196±18 pg/ml to 435±73 ng/ml. The level of C-ANP reached a steady state. A close linear correlation was observed between increases in MLAP and normalized C-ANP. However, the peak time of C-ANP lagged 10 min behind MLAP. These results indicate that it takes 10 min for P-ANP to reach a steady state in fully responding to a volume load, and that the long-term volume load is a prerequisite to the response of the ANP providing system.     

Seasonal changes in the hypothalamo-pituitary-testes axis of the Japanese wood mouse (Apodemus speciosus)

Seasonal changes in the hypothalamo-pituitary-testes axis of the Japanese wood mice (Apodemus speciosus) were studied. The testes, epididymis, pituitary and hypothalamus were compared between mice in the breeding season (July) and non-breeding season (October) using morphological techniques, and the plasma testosterone level was evaluated by enzyme immunoassay. Significant differences in these tissues were observed between the breeding season and the non-breeding season. Specifically, differences in the non-breeding season included 1) a decline in testicular and epididymal weights, arrest of spermatogenesis and decrease of serum testosterone concentration; 2) a decrease in the number of luteinizing hormone (LH)-, follicle stimulating hormone (FSH)-, prolactin (PRL)-, and growth hormone (GH)-immunoreactive cells, and decrease in the size of FSH, PRL, and GH-immunoreactive cells; and 3) an increase in the size of gonadotropin-releasing hormone (GnRH)-immunoreactive neurons. Our findings indicate that the male adult Japanese wood mouse exhibits unique seasonal changes in the hypothalamo-pituitary-testes axis which are not found in laboratory mice.     

Reversible Photo‐Mechanical Switching Behavior of Azobenzene‐Containing Semi‐Interpenetrating Network under UV and Visible Light Irradiation

Summary: Light‐induced reversible changes in elasticity of semi‐interpenetrating network (semi‐IPN) films bearing azobenzene moieties were achieved under both ultraviolet (UV) and visible light irradiation. The semi‐IPN film was prepared by a cationic copolymerization of azobenzene‐containing vinyl ethers in a linear polycarbonate (PC) film as a matrix. When the irradiation was switched on and off, the semi‐IPN film showed rapid reversible deformation with the same behavior occurring over a range of wavelengths, including both the UV and visible regions. The observed reversible deformation of the film was attributed to the decrease in the film's elasticity, which was assumed to be caused by the frequent trans‐cis cycling isomerization of azobenzene moieties taking place during the UV and visible light irradiation. This cycling makes it difficult for the azobenzene groups to aggregate, thus hindering their ability to function as pseudo‐crosslinking points.

     

The role of tumor necrosis factor (TNF)-α in the antitumor effect of intrapleural injection of Lactobacillus casei strain Shirota in mice

The involvement of several cytokines in the antitumor effect induced by intrapleural (i.pl.) injection of heat-killed cells of Lactobacillus casei strain Shirota (LC 9018) in mice was investigated. Injection of LC 9018 i.pl. into Meth A fibrosarcoma (Meth A)-bearing mice not only significantly prolonged the survival of the mice, but also effectively inhibited the accumulation of malignant pleural fluid in the thoracic cavity. In the thoracic cavity of tumor-bearing mice treated with LC 9018, we observed large amounts of several cytokines including interleukin (IL)-1β, interferon (IFN)-γ, IL-12 and tumor necrosis factor (TNF)-α. Both anti-IFN-γ and anti-IL-12 monoclonal antibody (mAb) treatments partially diminished the antitumor activity of LC 9018 in vivo, while the treatment of anti-IL-1β mAb did not influence the survival of the mice. However, anti-TNF-α mAb treatment completely abolished the antitumor effect of LC 9018 in vivo, suggesting that in this model LC 9018 has a survival-prolonging effect involving certain cytokines. Moreover, i.pl. injection of mouse recombinant TNF-α into Meth A-bearing mice pretreated with anti-TNF-α mAb partially restored the survival-enhancing effect of LC 9018. These results led us to conclude that TNF-α induced by i.pl. injection of LC 9018 plays an important role in the antitumor effect of LC 9018 in vivo. Received: 22 February 1999     

Non-IgG1 nature of cutaneous basophil hypersensitivity factor in contact sensitivity. II. Demonstration of antigen-dependent basophil chemotactic activity of cutaneous basophil hypersensitivity factor

It was recently demonstrated that there was a specific activity to induce basophil-rich skin reaction in the sera of contact-sensitized guinea pigs (CBH factor, CBH-F). In the in vitro chemotactic assay system, CBH-F was shown to have weak basophil chemotactic activity but enhanced its activity in the presence of corresponding antigen(s). Furthermore, basophil chemotaxis in reaction to the antigen(s) was observed when the cells were preincubated with CBH-F. It worked mainly for Percoll-separated bone marrow basophils but not for oil-induced peritoneal macrophages. Immunological analysis revealed that CBH-F was a protein with a small molecular weight (MW 4-6 X 10(4] with an antigen binding site and isoelectric point of between 4.5 and 5.0. It did not show any characteristics of IgG1 or IgG2 on immunoadsorbent column and immunoelectrophoresis. Enzyme treatment with insoluble trypsin eliminated the chemotactic activity but this was not the case with neuraminidase treatment.     

A single gene controls resistance to Japanese encephalitis virus in mice

Summary The inheritance of resistance to Japanese encephalitis virus (JEV) was investigated using inbred strains of mice to study genetic resistance against JEV infection. C57BL/6 mice immunized intraperitoneally (i.p.) with an infective dose of JEV were resistant to intracerebral (i.c.) challenge with JEV, whereas most C3H/He mice treated in the same manner died. C57BL/6 mice developed this resistance 2 weeks earlier than C3H/He after intraperitoneal (i.p.) immunization. Passive transfer of spleen cells from immunized C57BL/6 protected the recipient mice from i.c. challenge, while transfer from immunized C3H/He was less effective. Since immunized athymic nude mice were not resistant to i.c. challenge with JEV, T lymphocytes were considered to be necessary for protection. When F₁, F₂ and backcross mice derived from C57BL/6 and C3H/He were challenged i.c. with JEV after i.p. immunizations, the number of resistant and susceptible mice were consistent with Mendelian ratios. Thus it can be concluded that resistance to JEV in mice was controlled by a single, dominant autosomal gene which was not linked toa (non agouti)-locus (chromosome 2).