Apoptosis-inducing protein derived from hepatocyte selectively induces apoptosis in lymphocytes

The liver is where lymphocytes undergo activation-induced cell death (AICD) at the resolution phase of an immune response, which is crucial for homeostasis of the immune system and prevention of autoimmunity. Exploring the machinery of AICD in the liver, we found that a primary culture supernatant of murine hepatocytes had an antiproliferative effect on antigen-stimulated T clone and T lymphoma cells. Biological study showed that the antiproliferation was due to induction of apoptosis in a caspase-dependent manner. The apoptosis-inducing potential was sensitive to trypsin, heat (> 70 degrees ) and acid (< pH 5) treatment but could not be neutralized by anti-tumour necrosis factor-alpha, anti-Fas ligand, or anti-transforming growth factor-beta antibodies. Biochemical study of the isolated and purified apoptosis-inducing component from the supernatant showed that it was a protein with a molecular mass of about 68,000-70,000. It induced apoptotic change in murine T and B cells, and to a lesser degree, in human lymphoid cells, but not in macrophages. Biochemical and biological characteristics distinguish this protein from others that have been reported to induce apoptosis of lymphocytes. The identification of an apoptosis-inducing protein derived from murine hepatocytes, which selectively induces apoptosis in lymphocytes, suggests one possible mechanism for immune suppression in the liver.     

Ramp rate of blood pressure changes does not affect aortic afferent sensitivity in anesthetized rats

To investigate whether the rate of change in blood pressure affects the sensitivity of the aortic baroreceptor afferent response, the change in aortic nerve activity (ANA) to two different rates of ramp increase in mean blood pressure (MBP), elicited by phenylephrine administration, was determined in the rat under urethane (1.5 g kg⁻¹) anesthesia. The sensitivity of the increase in ANA following a rapid (average ramp rate, 9.14 ± 0.60 mmHg s⁻¹, n = 11) or gradual (1.78 ± 0.24 mmHg s⁻¹, n = 11) increase in MBP was 2.03 ± 0.14% and 1.81 ± 0.20% of baseline mmHg⁻¹, respectively. These values were not significantly different from each other (P = 0.16). Furthermore, we found no correlation between the rate of ramp increase in MBP and the sensitivity of the increase in ANA (r = 0.24, P = 0.29, n = 22). These results suggest that, at least within the normal physiological range of MBP, the rate of the ramp change in blood pressure does not affect aortic baroreceptor afferent sensitivity in the anesthetized rat.     

Comparison of alternate-day versus consecutive-day treatment with S-1: assessment of tumor growth inhibition and toxicity reduction in gastric cancer cell lines in vitro and in vivo

Background  The toxic effects of S-1 can lead to discontinuation of treatment. Strategies for reducing toxicity without compromising therapeutic effectiveness are required. Methods  We used the human gastric cancer cell lines MKN28 and MKN45 to examine such strategies in vitro. The cell lines were treated with three different regimens, given on alternate days (alternate-day) or on consecutive days (consecutive-day). On consecutive days, treatment A provided the same total dose as the alternate-day treatment, and treatment B was given for the same number of days as the alternate-day treatment. A fourth group served as control. In vitro, the relative inhibition (RI) of tumor growth by 5-fluorouracil was calculated using the 2-(2-methyl-4-nitrophenyl)-3-(4-nitrophyl)-5-2, 4-disulfophenyl)-2H-tetrazolium (WST-8) method. We also carried out an in vivo experiment in which tumor-bearing nude mice (BALBc/nu-nu) were used to examine the antitumor activity of S-1. Leukocyte counts and gastrointestinal mucosal injury were compared in mice that received alternate-day and consecutive-day treatments. Results  In vitro, for MKN28, the RI was 22.9% for alternate-day, 34.1% for consecutive-day A, and 37.7% for consecutive-day B treatments. For MKN45, the RI was 51.1% for alternate-day, 52.2% for consecutive-day A, and 50.5% for consecutive-day B treatments. In vivo, for MKN28, the treated groups showed higher inhibition than the control, and inhibition of tumor growth was higher with alternate-day than with consecutive-day treatment. The RI was significantly higher with alternate-day (49.3%) than with consecutive-day treatment (16.2%; P < 0.05). For MKN45, the RI was greater than 50% in both treated groups. With consecutive-day treatment, 5 of the 14 mice used died during treatment. Leukocyte counts were lower in the mice with consecutive-day than with alternate-day treatment, or control. Atrophic changes and inflammatory cell infiltration of the small intestinal mucosa were severe after consecutive-day, but minimal after alternate-day treatment. Conclusion  Experimentally, alternate-day treatment with S-1 is equivalent to consecutive-day treatment in terms of RI of tumor growth, with lower toxicity.     

Diagnosis of Atlantoaxial Subluxation in Morquio's Syndrome and Spondyloepiphyseal Dysplasia Congenita

Compression of the spinal cord due to atlantoaxial subluxation was diagnosed in a patient with Morquio's syndrome and in another with spondyloepiphyseal dysplasia (SED) congenita by cervical radiography and magnetic resonance imaging (MRI). The patient with Morquio's syndrome, a 15 year old boy, had no neurologic symptoms and his somatosensory evoked potential (SSEP) was normal. However, MRI demonstrated spinal cord compression at C1-C2. In contrast, the patient with SED congenita, an 11 year old girl, had neck pain, hyperreflexia and loss of vibration sense in both legs. These findings were explained by the absence of P3 and later waves in SSEP and by compression of the spinal cord observed on MRI. Both SSEP and MRI should be used for evaluating disorders in which atlantoaxial subluxation might be present.     

Establishment of a retrodifferentiated cell line from a single differentiated rat myelomonocytic leukemia cell: Possible roles of retrodifferentiation in relapses of leukemia after differentiation-inducing therapy

In order to demonstrate possible roles of retrodifferentiation in relapses after differentiation therapies, we have established a retrodifferentiated cell line (RD-1) from a single rat myelomonocytic leukemia cell which differentiated into a macrophage-like cell by treatment with lipopolysaccharide (LPS). The established RD-1 cells showed microscopic features slightly maturer than their parent cells. The RD-1 cells had the ability to differentiate into macrophage-like cells by treatment with fewer doses of LPS than those for parent cells. All rats inoculated with the parent cells (more than 10²/rat) died within 50 days. Rats inoculated with 10⁴ RD-1 cells survived for more than 120 days, whereas two out of four rats inoculated with 10⁵ cells and all the rats inoculated with 5 × 10⁵ cells died of leukemia. These results suggest that RD-1 cells are retrodifferentiated cells from a single rat myelomonocytic leukemia cell which differentiated into a macrophage-like cell; they have similar phenotypes and lower tumorigenicity than the parent cells and they also suggest that the appearance of retrodifferentiated leukemia cells may be responsible for relapse after differentiation therapy for leukemia in some cases.     

Renal cell carcinoma producing α-fetoprotein (AFP) with a unique lectins-affinity profile

Renal cell carcinoma (RCC) producing α-fetoprotein (AFP) is a rare entity and merely 7 cases have been reported so far. The present case, a 71-year-old woman, showed a high serum AFP level of 204 ng/ml. The RCC of the autopsied right kidney consisted mainly of spindle-shaped or bizarre sarco-matous tumor cells. AFP was immunolocalized only in the concomitant clear cell component. Concanavalin A (Con A)-nonadsorption rate of serum AFP was 42%, which was an intermediate value between those of yolk sac tumors and metastatic liver carcinomas. Lens culinalis agglutinin (LCA)-affinity study of the patient's AFP showed an unknown peak X, which was eluted between the known peaks 2 and 3. These results suggest a certain structural alteration in carbohydrate moieties of the AFP derived from this RCC. A review of the clincopathologic features of 8 patients with AFP-producing RCC was made to understand the pathophysiology of AFP-producing neoplasms. © Wiley-Liss, Inc.     

Polypoidal choroidal vasculopathy: natural history

PURPOSE: The present study was performed to clarify the long-term natural history of polypoidal choroidal vasculopathy (PCV). DESIGN: Prospective, consecutive observational case series. METHODS: Fourteen eyes of 12 consecutive patients with PCV were prospectively followed in our clinic for at least 2 years without any treatment after a first visit to the clinic between February 1996 and November 1998. All patients underwent complete ophthalmologic examination, color fundus photography, and fluorescein and indocyanine green (ICG) angiography at regular intervals. Inclusion criteria were as follows: eyes had serous and/or hemorrhagic pigment epithelium detachment (PED) and retinal detachment in the posterior pole, and ICG angiography revealed a branching vascular network with polypoidal dilations at the terminals of the network. Exclusion criteria were as follows: other diseases such as exudative age-related macular degeneration, high myopia, angioid streaks, and presumed ocular histoplasmosis syndrome, and patients who previously underwent any ocular surgery. RESULTS: Patients were followed for mean of 39.9 months (range, 24-54 months). PCV was present in 10 (83%) men and two women and in the elderly (mean age 68.1 years), usually unilateral (83%) with vascular lesions located at the macula (93%). The PCV manifested in two patterns, exudative and hemorrhagic. In the exudative pattern, serous PED and retinal detachment were predominant at the macula. The hemorrhagic pattern was characterized by hemorrhagic PED and subretinal hemorrhage at the macula. ICG angiography revealed polypoidal choroidal neovascularization that was changeable in appearance and repeatedly grew and spontaneously regressed, but the vascular network persisted. In some eyes, a collection of small aneurysmal dilations of vessels resembling a cluster of grapes appeared and all of them had marked bleeding and leakage and worse outcome. CONCLUSION: Polypoidal choroidal vasculopathy is a long persistent chronic disease and the patients had a variable course. Fifty percent of the patients had a favorable course. In the remaining half of the patients, the disorder persisted for a long time with occasional repeated bleeding and leakage, resulting in macular degeneration and visual loss. Eyes with a cluster of grapes-like polypoidal dilatations of the vessels had a high risk for severe visual loss.     

Effects of local administration of interferon-beta on proliferation of retinal pigment epithelium in rabbit after laser photocoagulation

PURPOSE: To investigate whether local administration of interferon (IFN)-beta promotes proliferation of the retinal pigment epithelium (RPE) in vivo. METHODS: Following local injection of IFN-beta into the sub-Tenon space of rabbit eyes, the penetration of IFN-beta into various intraocular areas was determined by means of enzyme-linked immuno-adsorbent assay. Retinal lesions were produced by laser photocoagulation (PC), and IFN-beta (1 x 10(6) IU, 1 x 10(5) IU, or 1 x 10(4) IU) was administered into the sub-Tenon space. Physiological saline was substituted for IFN-beta in controls. The proliferation of RPE cells was inspected histopathologically. RESULTS: After IFN-beta administration, IFN-beta was found in all intraocular areas examined, with the highest concentration detected in the choroid. After PC, profuse proliferation of RPE cells began earlier in the rabbits that received the highest dose of IFN-beta than in the control rabbits; repair of the central part of the coagulated lesion in those rabbits was complete within 7 days after PC. In control rabbits, the histopathologic wound repair process proceeded more slowly and to a limited extent. Proliferation of RPE cells in the low and medium dose IFN-beta-treated rabbits was similar to that in the control rabbits. CONCLUSION: The present study demonstrates that repair of the PC-induced retinal lesions, particularly the proliferation of RPE cells, is promoted in vivo by local administration of IFN-beta.     

Hemodynamic significance of histamine synthesis and histamine H<Subscript>1</Subscript>- and H<Subscript>2</Subscript>-receptor gene expression during endotoxemia

The hypothesis that endotoxemia may modify histamine synthesis or histamine receptor expression and that these changes may contribute to cardiovascular dysfunction was tested in rabbits which were rendered endotoxemic by lipopolysaccharide (LPS; 100 micro g/kg, i.v.). The plasma histamine concentration was elevated shortly after LPS, remaining elevated (a 50-fold increase) over the experimental period of 6 h. The sustained increase in plasma histamine was associated with a time-dependent increase in expression of histidine decarboxylase (HDC) in different tissues including atrium, as determined by Western blot analysis. The H(1)-receptor antagonist diphenhydramine significantly shortened the duration of the initial hypotension and the H(2)-receptor antagonist ranitidine greatly suppressed the lasting tachycardia following LPS injection. Northern blot analysis showed that LPS dramatically induced gene expressions of histamine H(1)- and H(2)-receptors in cardiac tissues. In right atrium isolated from the septic animal, the positive chronotropic effect of histamine was significantly diminished. This was possibly due to a marked reduction in G(s)(alpha) protein expression, indicating the impaired H(2)-receptor cellular signaling. In conclusion, LPS-induced endotoxemia causes prominent increases in production of histamine through induction of HDC and in gene expression of histamine receptors. We suggest that overproduction of histamine may be partly responsible for the hemodynamic alterations of endotoxemia.     

COX selectivity and animal models for colon cancer

Early experiments performed during 1980s and 1990s using carcinogen-induced rat intestinal tumor models demonstrated the inhibitory effects of non-steroidal anti-inflammatory drugs (NSAIDs) on intestinal tumorigenesis. Furthermore, epidemiological studies and clinical trials for familial adenomatous polyposis (FAP) patients supported the possibility that NSAIDs can be used as chemopreventive agents. The major target molecules of NSAIDs are cyclooxygenases (COX), which catalyze the rate-limiting step of prostaglandin biosynthesis. Two isoenzymes of COX have been identified; COX-1 and COX-2. Whereas COX-1 is expressed constitutively in most tissues and responsible for tissue homeostasis, COX-2 is inducible and plays an important role in inflammation and intestinal tumorigenesis. A genetic study using compound mutant mice of COX-2(-)/(-), and Apc(Delta716) which is a model for human familial adenomatous polyposis (FAP), directly demonstrated that induction of COX-2 is critical for intestinal polyp formation. Numerous studies have also demonstrated that COX-2 selective inhibitors suppress intestinal polyp formation in Apc gene-mutant mice, and xenografted cancer cell growths. In addition, stimulation of angiogenesis is one of the major effects by COX-2 expression that is induced in the polyp stromal cells. On the other hand, another study indicated that COX-1 also plays an important role in the early stage of intestinal tumorigenesis. These data from animal model studies should be helpful in understanding the in vivo mechanism(s) of tumor suppression by NSAIDs or COX-2 inhibitors. Here, we review the animal studies that have been published as of August 2001, and reported to suppress intestinal tumor growths by NSAIDs or COX-2 inhibitors.