HLA-DR+CD3+ and CD8+ cells are increased but CD4+CD45RA+ cells are reduced in the peripheral blood in human scrub typhus

Immunological studies on scrub typhus (ST) have been limited mostly to animals despite the possible difference in the immune responses among the species of the hosts. To investigate in vivo cellular immune responses to ST in humans, we characterized T-cell subsets in the peripheral blood samples from 30 healthy control subjects (HC), 11 patients with nonrickettsial acute infections (NRAI), and 6 patients with ST by a dual labeling method of flow cytometry. In ST, HLA-DR+CD3+ cells were greatly increased compared with those in HC and NRAI (HC, 2.3 +/- 1.3%; NRAI, 4.5 +/- 4.4%; ST, 32.5 +/- 14.7% values are means +/- SD). CD8+ cells were also significantly increased (HC, 29.5 +/- 5.9%; NRAI, 30.5 +/- 9.4%; ST, 44.9 +/- 11.5%), while CD4+CD45RA+ cells were significantly reduced (HC, 23.6 +/- 8.2%; NRAI, 23.3 +/- 12.3%; ST, 12.9 +/- 7.1%) in ST. The unique changes in the T-cell subsets in the peripheral blood samples from the patients with ST support the importance of the cellular immune responses to the natural infection of ST in humans.

Hyperresponsiveness of cardiac muscles to histamine in reserpine-treated guinea pigs

The hyperresponsiveness of cardiac tissue to histamine following treatment with reserpine was pharmacologically characterized. Guinea pig hearts were isolated 24 hours after intraperitoneal administration of 5 mg/kg reserpine. This treatment resulted in a complete depletion of tissue norepinephrine. Reserpine treatment potentiated the positive inotropic response of isolated perfused hearts to histamine at doses ranging from 0.3 to 3 micrograms (23 to 57% increase for reserpine-treated animals vs. 14 to 32% increase for control animals). Isolated left ventricular papillary muscle of reserpine-treated guinea pig hearts also showed hyperresponsiveness to histamine at concentrations of 0.1 microM or greater. The hyperresponsiveness of the papillary muscle contraction of the reserpine-treated animals to histamine was abolished in the presence of 1 microM cimetidine, but not attenuated in the presence of 1 microM diphenhydramine. This hyperresponsiveness was not modified by 1 microM bunazosin or 1 microM propranolol. The results suggest that H2-receptor mediated action plays a role in the hyperresponsiveness of cardiac muscles to histamine.

Interaction of poly(ADP-ribose)polymerase with DNA polymerase alpha

Homogeneously purified poly(ADP-ribose) polymerase (PARP) specifically stimulated the activity of immunoaffinity-purified calf or human DNA polymerase alpha by about 6 to 60-fold. Apparently, poly(ADP-ribosyl)ation of DNA polymerase alpha was not necessary for the stimulation. The effects of PARP on DNA polymerase alpha were biphasic: at very low concentrations of DNA, it rather inhibited its activity, whereas, at higher DNA concentrations, PARP greatly stimulated it. The autopoly(ADP-ribosyl)ation of PARP suppressed both its stimulatory and inhibitory effects. By immunoprecipitation with an anti-DNA polymerase alpha antibody, it was clearly shown that PARP may be physically associated with DNA polymerase alpha. Stimulation of DNA polymerase alpha may be attributed to the physical association between the two, rather than to the DNA-binding capacity of PARP, since the PARP fragment containing only the DNA binding domain showed little stimulatory activity. The existence of PARP-DNA polymerase alpha complexes were also detected in crude extracts of calf thymus.

Characterization of guinea pig estrogen sulfotransferase expressed by Chinese hamster ovary cell-K1 stable transfectants

Estrogen sulfotransferase (EST) activity expressed by Chinese hamster ovary (CHO)-K1 cells stably transfected with a plasmid containing a guinea pig EST complementary DNA insert was subjected to biochemical characterization, and the EST protein was further examined by nondenaturing isoelectric focusing and immunoblot analysis. CHO-K1 cells transfected with the same plasmid without the EST complementary DNA insert as well as untransfected CHO-K1 cells did not demonstrate either EST activity or the presence of an immunologically related protein. The EST expressed by the stably transfected CHO-K1 cells was found to manifest Michaelis-Menten kinetics and would use only estrogenic steroids as substrates, whereas other forms of steroids, such as pregnenolone, dehydroepiandrosterone, cortisol, and testosterone, were not acted on. When 17 beta-estradiol was used as a substrate, sulfonation occurred exclusively at the 3 position; 17-sulfonate was not formed. Thus, the expressed EST acted selectively on the 3-hydroxyl group of phenolic steroids. The apparent Km values for estrone, 17 beta-estradiol, and estriol were 60, 70, and 40 nM, respectively. The maximum velocity (Vmax) determinations for estrone and 17 beta-estradiol were equivalent, whereas the Vmax for estriol was reduced by 33%. Of the three estrogens, only 17 beta-estradiol caused substrate inhibition at a high concentration. Steroid sulfonation requires 3'-phosphoadenosine-5'-phosphosulfate (PAPS) as the active sulfonate donor, and the Km value for PAPS was 1.2 microM. In steroid sulfotransferase reactions, two products are formed: the sulfonated steroid product and the desulfonated cofactor, 3'-phosphoadenosine-5'-phosphate (PAP). The sulfonation of 17 beta-estradiol was inhibited by PAP in a dose-dependent manner. In addition, the Km for PAPS was increased by PAP, whereas the Vmax was unaffected, indicating competitive inhibition (Ki, approximately 0.52 microM). The EST protein expressed by the CHO-K1 cell stable transfectants demonstrated a mol wt of 34 kilodaltons, as determined by sodium dodecyl sulfate-gel electrophoresis. Additionally, when the expressed EST protein was subjected to isoelectric focusing, it was found to consist of multiple charge isoforms. These findings are comparable to what has been previously reported for native guinea pig adrenocortical EST. Furthermore, the charge isoform pattern that was demonstrated for the expressed EST was similar to the pattern observed for the native protein.

Alterations in vascular pattern of the developing palate in normal and spontaneous cleft palate mouse embryos

The alterations in the vascularization of the developing palate were studied through the use of resin cast images of vascular networks in normal and spontaneous cleft lip and palate (CL/Fr) mouse embryos (crown rump [CR] Length 9-18 mm, body wt. 0.11-0.65 g). A more dense vascular plexus was observed in the oral side than in the nasal side before the reorientation of the palatal shelves. Prominent terminal dilatations of the vascular plexus were observed in the extreme medial edge of the elevating palatal shelves which may exert significant force for palatal shelf elevation. The vascular plexus showed a lateral extension. Many small spherical masses of resin were observed in the medial edge of the palatal shelves at the time of medial extension and during fusion, indicating some changes occurring in the capillary wall leading to the resin leakage. In the spontaneous cleft group, a similar vascular pattern was observed, but the greater palatine artery showed discontinuity in the premaxillary region at an early stage. At the same time, terminal dilatations were delayed and frequently absent in the contralateral shelf. After the reorientation of the palatal shelves, the vascular plexus formed an irregular lattice pattern. Dilated vasculature was apparent in the anterior nasopalatine region, indicating the persistence of a more primitive vascular structure in the spontaneous cleft embryos. However, the area where capillary dilatation occurred was different between unilateral and bilateral cleft embryos. In conclusion, blood vessels in the palatal shelves are underdeveloped and remained immature in cleft lip and palate embryos and showed different patterns in the anterior nasopalatine region between unilateral and bilateral cleft embryos. These variant vascular patterns may be due to the inadequate blood supply to the nasopalatine region from the early embryonic stages possibly resulting from the discontinuity of the greater palatine artery.

Differential inhibition of eukaryotic DNA polymerases by halenaquinol sulfate, a p-hydroquinone sulfate obtained from a marine sponge

Halenaquinol sulfate, a p-hydroquinone sulfate obtained from a marine sponge, inhibited the activity of eukaryotic DNA polymerases in varying degrees; the Ki values for DNA polymerases, alpha, beta, delta and epsilon were 1.3, 80, 17.5 and 2.0 microM, respectively, whereas it was less effective against E. coli DNA polymerase I. The inhibition occurred competitively with each of dATP and dTTP, but non-competitively with dCTP, dGTP and the template DNA. Thus, halenaquinol sulfate is demonstrated to be a potential inhibitor of DNA polymerases alpha and epsilon, and be a useful tool for analyzing the dNTP binding sites of DNA polymerases.

Sphingosine inhibits the synthesis of RNA primers by primase in vitro

We have previously shown the presence of sphingomyelin and sphingomyelinase in cell nuclei, suggesting that they may play a role in the intranuclear production of sphingosine, a potent bioactive molecule modulating diverse cellular functions. In the present study, the direct effects of sphingosine (C18:1) on the activity of DNA replication/repair polymerases were studied in vitro. Sphingosine had no effect on DNA polymerases alpha and beta and slightly inhibited DNA polymerases gamma, delta, and epsilon. In contrast, sphingosine strongly inhibited the activity of primase in a dose-dependent manner. On the other hand, dihydrosphingosine (C18:0), glycolipids, sphingomyelin, and ceramide had no effect on primase activity. Sphingosine equally inhibited the activity of primase complexed with DNA polymerase alpha, as well as its free form, with a Ki value of 4 microM. A gel-retardation analysis showed that the binding of primase with 32P-labeled template DNA was suppressed by sphingosine. Inhibition by sphingosine was competitive with the DNA template, but not with the substrate NTPs. After product analysis, a dose-dependent decrease in the amount of RNA primer products, consisting mainly of 10- and 11-mers, was observed in the presence of sphingosine, indicating that it inhibits the synthesis of RNA primers by primase. Sphingosine, however, had no effect on T7 RNA polymerase.

[Hemophagocytic syndrome observed in a patient with systemic lupus erythematosus]

A 52-year-old woman was admitted to our hospital because of a skin rash, high fever and myalgia. She had been diagnosed ten years ago by a dermatologist as having MCTD (mixed connective tissue disease). At the time of admission a diagnosis of active SLE was made by fulfilling four of the 1982 ARA criteria together with increasing levels of anti-DNA antibody and low levels of complements. Prednisolone (PSL) given orally in an initial dosage of 60 mg/day was effective during the first 6 weeks. Then a high fever, skin rash and pancytopenia appeared without active findings of SLE. Infection caused by bacteria, fungus or virus was suspected, but no infectious agent was present in cultures derived from blood or other sources. Antimicrobic drugs used were not effective at all. The clinical picture was suggestive of a drug allergy, but no causative drug was found. A diagnosis of hemophagocytic syndrome (HPS) was made because of the increased number of unusual hemophagocytic cells in the bone marrow. High levels of serum ferritin and neopterin, which are known to reflect macrophage activation, supported the diagnosis of HPS. HPS is characterized by activated phagocytosis presumably induced by hypersecretion of cytokines. Malignant lymphoma and infection are the two representative diseases which may cause HPS. Recently, an acute lupus HPS was reported in patients with active SLE. Here we reported a case of reactive HPS observed in a patient with SLE who had been receiving high dose PSL. Symptoms and findings of the patient gradually disappeared in several weeks after rapid reduction of the PSL dose.(ABSTRACT TRUNCATED AT 250 WORDS)

IFN-alpha inhibits antigen-induced eosinophil and CD4+ T cell recruitment into tissue

In a murine model of airway late phase reaction, we have previously shown that Ag-induced eosinophil recruitment into the tissue of sensitized mice is mediated by CD4+ T cells and IL-5. To determine whether IFN-alpha regulates Ag-induced eosinophil recruitment into tissue, we studied the effects of rIFN-alpha, endogenous IFN-alpha production induced by poly I.C, and anti-IFN-alpha mAb on the eosinophil infiltration of the trachea induced by Ag inhalation in mice. The i.p. administration of rIFN-alpha prevented Ag-induced eosinophil infiltration in the trachea of sensitized mice. In addition, the inhibitory effect of rIFN-alpha on Ag-induced eosinophil infiltration was not recovered by pretreatment with anti-IFN-gamma mAb. The administration of rIFN-alpha also inhibited Ag-induced CD4+ T cell infiltration in the trachea. However, the administration of rIFN-alpha did not significantly affect blood eosinophil counts nor the number of blood and splenic CD4+ T cells. On the other hand, pretreatment with anti-murine IFN-alpha mAb enhanced Ag-induced eosinophil and CD4+ T cell infiltration in the trachea. Finally, endogenous IFN-alpha/beta production induced by poly I.C also inhibited Ag-induced eosinophil infiltration in the trachea and this inhibition of the eosinophil infiltration was abrogated by pretreatment with anti-IFN-alpha/beta mAb. These results indicate that IFN-alpha suppresses Ag-induced eosinophil and CD4+ T cell recruitment into tissue.

[Imaging and clinical significance of hepatic portal venous gas seen in adult patients]

In 10 adult patients with hepatic portal venous gas (HPVG), the clinical significance of HPVG and the efficacy of X-ray computed tomography (CT) were evaluated. HPVG was associated with ischemic bowel disease (n = 3), trauma (n = 4), liver abscess (n = 1), sepsis (n = 1), and unknown etiology (n = 1). The diagnostic ability of CT for the detection of HPVG was far superior to that of plain abdominal radiograph. Of 9 patients who underwent CT, HPVG located in the left hepatic lobe in all patients, and also in right hepatic lobe in 7 patients. Gas could be recognized in the left lobe and the anterior segment of the right lobe more clearly than in the posterior segment of the right lobe because of its larger amount of intravenous collection. The mortality rate of our cases was 100%. Gas was demonstrated simultaneously in the portal vein radicles and hepatic veins on CT in 4 patients with no clinical evidence of sepsis, which suggested the possibility of intraparenchymal shift of gas from the portal vein into the hepatic vein. In a single case with sepsis, gas was noted in various vessels, including arteries, in addition to the portal venous system. The authors conclude that HPVG is still a grave sign in Japan and prompt appropriate treatment is required. CT may be of great value in the early detection of HPVG and may indicate its etiology.

Direct evidence of neuron impairment by oral infection with verotoxin-producing Escherichia coli O157:H- in mitomycin-treated mice

We developed a mouse model of acute encephalopathy induced by verotoxin 2 variant (VT2v)-producing Escherichia coli. Three-week-old mice were inoculated intragastrically with approximately 10(10) CFU of E. coli O157:H- strain E32511/HSC and simultaneously given an intraperitoneal injection of mitomycin (MMC; 2.5 mg/kg). Drinking water containing 5 g of streptomycin sulfate per liter was given ad libitum from 3 days before the infection. From 1 to 2 days after bacterial inoculation, clinical features including weight loss, weakness, and flaccid paralysis of the extremities developed, usually culminating in death within 4 days. Diarrhea was not observed during the course of disease. No mice died in the absence of streptomycin or MMC treatment for 2 weeks after the oral bacterial infection. Judging from the clinical course and the biochemical and histological examination, the cause of death was not likely to be attributable to renal failure or to a side effect of MMC. To better understand the cause of death, we examined the brain cortex and spinal cord of the moribund mice by electron microscopy. Mice showing mortal symptoms were given horseradish peroxidase intravenously. The tracer was present in the endothelial basal lamina, in the surrounding extracellular spaces, and even in the neuron fibers of the brain cortex. Furthermore, immunoreactivity of VT2v, proved by the use of rabbit anti-VT2 serum, was localized selectively in the damaged myelin sheaths of neuron fibers which were accompanied by edematous axons in the brain cortex and spinal cord. These findings strongly suggest that VT2v is toxic to both endothelial cells and neurons in the central nervous system and subsequently causes fatal acute encephalopathy.

[Changes in fatty acid composition, platelet aggregability and RBC function in elderly subjects with administration of low-dose fish oil concentrate and comparison with younger subjects]

Anti-thrombotic and anti-atherogenic effects of eicosapentaenoic acid (EPA) through the modulation of various cell functions related to thrombogenesis have been reported recently. We previously reported that the administration of EPA at low doses could more effectively elevate the plasma EPA concentration in elderly subjects than in younger ones. Magnetic resonance imaging examination of the brain often reveals lacunar lesions in elderly subjects without any signs or symptoms of cerebrovascular diseases. In this study we clarified the effect of administration of low doses of fish oil concentrate on platelet and RBC function in elderly subjects, compared with younger subjects. Thirty six elderly subjects (mean age 78) without any signs or symptoms of cerebrovascular diseases, all receiving the same diet in the same lodging house for the aged, were divided into 3 groups. Different amounts of fish oil concentrate (0.25-0.5 g/day of EPA) were administered to the 3 groups, daily for more than 1 month. Changes of plasma fatty acid composition, platelet aggregability, whole blood viscosity and RBC deformability was examined before and after EPA administration. One month after EPA treatment, the plasma EPA content had increased dose dependently, with suppression of platelet aggregation and improvement of RBC function. In younger subjects receiving the same amount of EPA, the elevation of plasma EPA was less than that observed in the elderly. In summary, low dose EPA administration can improve the function of platelet and RBC to an anti-thrombotic state and would be useful to prevent the occurrence of cerebrovascular diseases in elderly subjects without any side effects.

p53 expression in myeloid cells of myelodysplastic syndromes. Association with evolution of overt leukemia

To assess p53 expression in the hematopoietic cells of the bone marrow in premalignant as well as malignant conditions, we examined immunohistochemically bone marrow biopsies from patients with myelodysplastic syndromes (MDS, n = 51), acute myeloid leukemia (n = 42) and as a nonneoplastic condition, aplastic anemia (n = 20) and samples from individuals who had no hematological disorder (control, n = 12). Nuclear accumulation of p53 protein was found in seven of 51 patients with MDS (14%) and two of 42 acute myeloid leukemia patients (5%), whereas patients with aplastic anemia and control subjects were uniformly negative for p53 protein. In the bone marrow of patient with MDS, p53-positive cells constituted about 5 to 30% of the total bone marrow cells. Two-color immunohistochemical analysis revealed that the p53-positive cells were also positive for the myeloid cell marker. Half of the MDS cases that evolved to overt leukemia (seven of 14) exhibited positive p53 reaction in the bone marrow at the time of initial diagnosis. This frequency (50%) was significantly higher than that in de novo acute myeloid leukemia cases. All of the seven MDS cases that exhibited p53 expression at the time of initial diagnosis developed overt leukemia later, and p53 expression was maintained throughout the progression of MDS. The results suggest that p53 mutations that occur in the myeloid cells in MDS may confer a growth advantage to these cells resulting in the progression to overt leukemia. Thus, immunohistochemical examination for p53 is very useful for predicting the evolution to overt leukemia from MDS.

IFN-alpha inhibits antigen-induced eosinophil and CD4+ T cell recruitment into tissue

In a murine model of airway late phase reaction, we have previously shown that Ag-induced eosinophil recruitment into the tissue of sensitized mice is mediated by CD4+ T cells and IL-5. To determine whether IFN-alpha regulates Ag-induced eosinophil recruitment into tissue, we studied the effects of rIFN-alpha, endogenous IFN-alpha production induced by poly I.C, and anti-IFN-alpha mAb on the eosinophil infiltration of the trachea induced by Ag inhalation in mice. The i.p. administration of rIFN-alpha prevented Ag-induced eosinophil infiltration in the trachea of sensitized mice. In addition, the inhibitory effect of rIFN-alpha on Ag-induced eosinophil infiltration was not recovered by pretreatment with anti-IFN-gamma mAb. The administration of rIFN-alpha also inhibited Ag-induced CD4+ T cell infiltration in the trachea. However, the administration of rIFN-alpha did not significantly affect blood eosinophil counts nor the number of blood and splenic CD4+ T cells. On the other hand, pretreatment with anti-murine IFN-alpha mAb enhanced Ag-induced eosinophil and CD4+ T cell infiltration in the trachea. Finally, endogenous IFN-alpha/beta production induced by poly I.C also inhibited Ag-induced eosinophil infiltration in the trachea and this inhibition of the eosinophil infiltration was abrogated by pretreatment with anti-IFN-alpha/beta mAb. These results indicate that IFN-alpha suppresses Ag-induced eosinophil and CD4+ T cell recruitment into tissue.