The Japanese experience with vaccinating schoolchildren against influenza

BACKGROUND

Influenza epidemics lead to increased mortality, principally among elderly persons and others at high risk, and in most developed countries, influenza-control efforts focus on the vaccination of this group. Japan, however, once based its policy for the control of influenza on the vaccination of schoolchildren. From 1962 to 1987, most Japanese schoolchildren were vaccinated against influenza. For more than a decade, vaccination was mandatory, but the laws were relaxed in 1987 and repealed in 1994; subsequently, vaccination rates dropped to low levels. When most schoolchildren were vaccinated, it is possible that herd immunity against influenza was achieved in Japan. If this was the case, both the incidence of influenza and mortality attributed to influenza should have been reduced among older persons.

METHODS

We analyzed the monthly rates of death from all causes and death attributed to pneumonia and influenza, as well as census data and statistics on the rates of vaccination for both Japan and the United States from 1949 through 1998. For each winter, we estimated the number of deaths per month in excess of a base-line level, defined as the average death rate in November.

RESULTS

The excess mortality from pneumonia and influenza and that from all causes were highly correlated in each country. In the United States, these rates were nearly constant over time. With the initiation of the vaccination program for schoolchildren in Japan, excess mortality rates dropped from values three to four times those in the United States to values similar to those in the United States. The vaccination of Japanese children prevented about 37,000 to 49,000 deaths per year, or about 1 death for every 420 children vaccinated. As the vaccination of schoolchildren was discontinued, the excess mortality rates in Japan increased.

CONCLUSIONS

The effect of influenza on mortality is much greater in Japan than in the United States and can be measured about equally well in terms of deaths from all causes and deaths attributed to pneumonia or influenza. Vaccinating schoolchildren against influenza provides protection and reduces mortality from influenza among older persons.

Comparative nucleotide sequence analyses of the entire genomes of B95a cell-isolated and vero cell-isolated measles viruses from the same patient

Experimental infection of monkeys with the IC-B strain of measles virus (MV), which was isolated in marmoset B lymphoblastoid B95a cells from an acute measles patient, caused clinical signs typical for measles, while infection by the IC-V strain isolated in African green monkey kidney Vero cells from the same patient did not cause any clinical signs in infected monkeys. The IC-B strain replicated only in B95a cells, whereas the IC-V strain replicated in both B95a and Vero cells (3,6). To clarify which gene or mutation(s) was responsible for the difference in these phenotypes, the nucleotide sequences of the entire genomes of the IC-B and IC-V strains were determined. Comparative nucleotide sequence analyses revealed only two nucleotide differences, one in the P/V/C gene and the other in the M gene, predicting amino acid differences in the P, V and M proteins and a 19 amino acid deletion in the C protein of the IC-V strain. The truncation in the C protein was confirmed for the IC-V strain by immunoprecipitation using the C protein specific antiserum. No nucleotide difference was found in the envelope H gene. These results indicated that nucleotide difference(s) in the P/V/C or/and M gene, and not H gene, was responsible for the different cell tropism and pathogenicity of MV in this case.

18F-FDG PET mapping of regional brain activity in runners

BACKGROUND

To examine regional metabolic changes in the human brain induced by free running in upright posture. METHODS.

EXPERIMENTAL DESIGN

Regional brain changes in glucose uptake induced by running were examined by comparing brain images obtained by positron emission tomography (PET) and 18F-fluorodeoxyglucose (FDG).

SETTING

The study was conducted at a research institute and involved participation of healthy young volunteers. Data sampling and analysis required special imaging device and special computer hardware/software.

PARTICIPANTS

Subjects were 17 healthy male volunteers. They were divided at random into two equal groups, those who ran 4-5 km and the others sat in the room.

MEASURES

differences in regional cerebral glucose uptake between runners and control groups were assessed statistically. Plasma glucose level was also measured and global cerebral uptake was estimated.

RESULTS

Running was associated with a relative increase of glucose uptake in the temporoparietal association cortex, occipital cortex, premotor cortex and the cerebellar vermis. The highest activity was noted in the temporoparietal association cortex. Activity of the primary sensorimotor cortex was higher in the superomedial part (leg motor area) than the lateral part (thorax and arm).

CONCLUSIONS

Running augmented energy consumption in the parieto-occipital region relative to the motor area, probably due to the higher energy consumption necessary for integration of multimodal sensory information than for generation of motor output. Our results indicate that FDG PET is a useful tool for brain mapping under various physiological conditions.

Regional cerebral glucose metabolism of patients with malignant diseases in different clinical phases

BACKGROUND

Psychological and psychiatric aspects of cancer patients have not been studied well in terms of functional neuroimaging. The aim of this pilot study was to investigate the relationship between regional cerebral metabolism and different clinical phases.

MATERIAL AND METHODS

Relative cerebral glucose metabolism of 77 Japanese patients with various types of malignant diseases was studied by positron emission tomography with 18F-fluorodeoxyglucose. They were subgrouped into the 1) pre-treatment, 2) post-treatment, 3) recurrence and 4) terminal patient groups. These subgroups were compared to the control group of 17 in-patients with benign diseases, using voxel-based Statistic Parametrical Mapping software (SPM).

RESULTS

Relative reduction in the regional cerebral metabolism was detected in the prefrontal and basolateral (inferolateral) prefrontal cortex, orbitofrontal cortex, anterior and posterior cingulate gyrus, insula, basal ganglia, hippocampus and thalamus in the pre-treatment group. The anterior and posterior cingulate gyri were hypometabolic only in the pre-treatment group. Hypometabolic areas were detected only in the basolateral prefrontal cortex, orbitofrontal cortex, ventral part of cingulate gyrus and insula in the post-treatment group. In the terminal group, the hypometabolic pattern seemed very close to that in the pre-treatment group. The results seemed to suggest that hypometabolic findings before treatments could reverse after treatments but became prominent again in terminal stages. These results do not contradict with previous epidemiological findings that high incidence of adjustment disorders was seen in earlier stages and more brain organic syndromes were seen in terminal stages.

CONCLUSION

It could be speculated that decreased metabolism in early stages reflects state-dependent changes and that decreased metabolism in the terminal stages reflects organic brain damages. brain of cancer patients show a fluctuation in the regional metabolism. This finding might give a suggestion that functional imaging could be used as a supplementary method for psychological evaluation of patients with severe diseases.

Predicting the reactivity of proteins from their sequence alone: Kazal family of protein inhibitors of serine proteinases

An additivity-based sequence to reactivity algorithm for the interaction of members of the Kazal family of protein inhibitors with six selected serine proteinases is described. Ten consensus variable contact positions in the inhibitor were identified, and the 19 possible variants at each of these positions were expressed. The free energies of interaction of these variants and the wild type were measured. For an additive system, this data set allows for the calculation of all possible sequences, subject to some restrictions. The algorithm was extensively tested. It is exceptionally fast so that all possible sequences can be predicted. The strongest, the most specific possible, and the least specific inhibitors were designed, and an evolutionary problem was solved.

[18F]FDG-PET study in dementia with Lewy bodies and Alzheimer's disease

1. The authors report two siblings with dementia with Lewy bodies (DLB). Both the older brother and the younger sister underwent positron emission tomography (PET) studies with [18F]-2-fluoro-deoxy-D-glucose (FDG) during life. The FDG-PET study demonstrated unique and pronounced metabolic impairment in the occipital cortex in both patients. The clinical diagnosis of DLB in the sister was confirmed by autopsy. 2. FDG-PET images from 11 patients with Alzheimer's disease (AD), 7 patients with DLB and 10 age-matched normal subjects were obtained and analyzed by the statistical parametric mapping (SPM) method. The SPM demonstrated a widespread metabolic reduction in the DLB group. The reduction was particularly pronounced in the visual association cortex in the DLB group compared to the AD group irrespective of clinical severity of the disease. 3. These findings suggest that functional neuroimaging techniques, including FDG-PET, will provide a valuable diagnostic aid to differentiate DLB from AD, and this will help detect DLB patients in the early stage of the disease.

Evaluation of resting brain conditions measured by two different methods (i.v. and oral administration) with18F-FDG-PET

Our aim was to evaluate regional differences between brain activity in two resting control conditions measured by 3D PET after administration of FDG through either the intravenous (i.v.) or the oral route. Ten healthy male volunteers engaged in the study as the i.v. group (mean age, 26 +/- 9.3 years, +/- S.D.) who received FDG intravenously and another 10 volunteers as the oral group (mean age, 27.9 +/- 11.3 years, +/- S.D.) who received FDG per os. A set of 3D-PET scans (emission and transmission scans) were performed in both groups. To explore possible functional differences between the brains of the two groups, the SPM-96 software was used for statistical analysis. The results revealed that glucose metabolism was significantly higher in the superior frontal gyrus, superior parietal lobule, lingual gyrus and left cerebellar hemisphere in the i.v. group than in the oral group. Metabolically active areas were found in the superior, middle and inferior temporal gyrus, parahippocampal gyrus, amygdaloid nucleus, pons and cerebellum in the oral group when compared with the i.v. group. These differences were presumably induced by differences between FDG kinetics and/or time-weighted behavioral effects in the two studies. This study suggests the need for extreme caution when selecting a pooled control population for designated activation studies.

Immunological and PCR analyses for Borna disease virus in psychiatric patients and blood donors in Japan

The involvement of Borna disease virus (BDV) in psychiatric diseases in humans remains controversial. T-cell memory response and seroprevalence of BDV in patients with psychiatric disorders and blood donors in Japan were evaluated collectively by Western blot (WB) analysis with inhibition test, electrochemiluminescence immunoassay, immunofluorescence assay, and T-cell proliferative response as well as detection of BDV p24 RNA in peripheral blood mononuclear cells (PBMCs). Positive proliferative responses to both BDV p40 and p24 proteins were detected in 9% of patients with mood disorders (4 of 45), 4% of schizophrenic patients (2 of 45), and 2% of blood donors (1 of 45). By WB analysis, the antibody to BDV p40 was detected only in 2% of patients with mood disorders (1 of 45). The BDV p24 antibody was detected in 2% of patients with mood disorders (1 of 45) and 9% of schizophrenic patients. (4 of 45) No plasma reacted with both BDV proteins. The finding of a lower seroprevalence than previously reported suggests the presence of false-positive cases in the previous report. BDV RNA was detected only in 2% of patients with mood disorders (1 of 45). In these three serological assays, T-cell responses, and PCR analysis, there was no significant difference in the prevalence among the three groups. However, we found three psychiatric patients who were positive for both BDV antibodies and T-cell proliferative responses and one patient who was positive for BDV RNA in PBMCs. These findings suggest the usefulness of the proliferative T-cell response and that certain individuals are infected with BDV or a BDV-related virus.

Inhibition of rubella virus growth by Fungizone

Fungizone added to agar overlay medium inhibited plaque formation in both size and number by rubella virus in rabbit kidney 13 cells. In the presence of 1 microg/ml of Fungizone, the diameter of the plaques was reduced to one half of that in the absence of the drug, and at 5 microg/ml, plaque formation was inhibited by 80%. When the drug was added to the culture medium, the growth of infectious virus was also inhibited with reduction in the synthesis of envelope glycoprotein E1 and capsid protein C in infected cells.

Regulation of the initiation of pancreatic digestive enzyme protein synthesis by cholecystokinin in rat pancreas in vivo

BACKGROUND & AIMS

Cholecystokinin (CCK) is known to stimulate the synthesis of digestive enzymes in the pancreas at the translational level. We investigated in vivo the biochemical regulation of initiation factors important for the stimulation of translation of digestive enzyme protein in rat pancreas by CCK.

METHODS

Intraperitoneal injection of CCK or intragastric administration of a trypsin inhibitor to elicit endogenous CCK release was followed by removal and preparation of pancreas for protein evaluation. Isoelectric focusing was used to evaluate the phosphorylation of the initiation factor eIF4E, and Western blotting and immunoprecipitation followed by Western blotting were used to study the phosphorylation state and amount of other interacting factors.

RESULTS

CCK treatment induced a time- and dose-dependent phosphorylation of pancreatic eIF4E and its binding protein (PHAS-I). Because the release of eIF4E from its binding protein as a result of phosphorylation is followed by formation of a messenger RNA cap-binding complex that includes the initiation factor eIF4G, we evaluated the association of eIF4G with released eIF4E and showed that it was increased by CCK. These events occurred over a range of CCK doses from 0.2 to 5 microg/kg. We also evaluated the effect of endogenous CCK by administering a synthetic trypsin inhibitor, camostat (100 mg/kg). Camostat treatment markedly increased the phosphorylation of both PHAS-I and eIF4E and the formation of eIF4E-eIF4G complex. Thus, both exogenous and endogenous CCK activate translational initiation factors in vivo.

CONCLUSIONS

Activation of translational machinery necessary for initiation of protein synthesis likely contributes to the normal postprandial synthesis of pancreatic digestive enzymes.

Whole-body energy mapping under physical exercise using positron emission tomography

We attempted to visualize dynamic adjustment of glucose utilization in humans in the whole-body organs during physical exercise by using three-dimensional positron emission tomography (3D-PET) and [18F]-2-fluoro-deoxy-glucose (FDG). Twelve healthy male volunteers collaborated on the study; six subjects were assigned to the resting control group (C) and the other six to the running group (E). Group E subjects performed running on a flat road for 35 min. After 15 min of running, subjects injected FDG and kept on running thereafter for another 20 min. Group C subjects sat on a comfortable chair in a quiet room for 35 min after the injection of FDG. After scanning by PET, the regions of interest (ROIs) were manually set on brain, heart, thorax, abdomen, lower extremities, and the rest of the body on the corresponding transaxial images. The uptake of FDG in each region was evaluated as the % fraction of FDG accumulation relative to the total amount of whole-body accumulation. The results revealed increase of FDG uptake after running in the lower leg muscles from 24.6 +/- 9.5% to 43.1 +/- 4.7% and in the heart from 2.3 +/- 0.4% to 2.8 +/- 0.6%. The differences were significant (P < 0.05). These increases reflect the rise in energy consumption in leg and heart muscles and were balanced by the reduction of energy consumption in the other part of the body. FDG uptake in the abdominal region reduced from 37.3 +/- 7.2% to 19.7 +/- 4.9%. However, FDG uptake in the brain remained stable, i.e., 11.9 +/- 2.8% at rest and 10.3 +/- 2.5% after exercise. Thus, 3D-PET is a tool to visualize the dynamic adjustment of energy consumption during physical exercise in humans.

Hydroxyapatite-coated nylon beads as a new reagent to develop a particle agglutination assay system for detecting Japanese encephalitis virus-specific human antibodies

BACKGROUND

Detection of Japanese encephalitis virus (JEV)-specific antibodies is done today by hemagglutination-inhibition assay (HIA), neutralization assay (NTA) and enzyme-linked immunosorbent assay (ELISA). These conventional assays are often difficult to perform in diagnostic laboratories with insufficient resources. An alternative antibody detection kit, which is simple, preservable and inexpensive, is needed for extended use in rural areas of Asia.

OBJECTIVES

(i) Characterization of a new antigen carrier, hydroxyapatite-coated nylon (Ha-Ny) beads, and (ii) evaluation of the JEV antigen-coated Ha-Ny beads as a reagent to detect anti-JEV antibodies in human serum samples.

STUDY DESIGN

We examined the Ha-Ny beads for hydroxyapatite content, precipitation efficiency and protein adsorption ability. We then developed a particle agglutination assay system using the JEV antigen-coated Ha-Ny beads, and tried out the newly developed assay system with reference serum samples.

RESULTS

The beads had the ability to adsorb 0.44 mg of lysozyme per gram. Sedimentation speed was 10.2 cm/30 min in phosphate buffered saline (PBS), pH 7.0. Binding of the JEV antigen on Ha-Ny beads was confirmed by scanning electron microscopy (SEM) and ELISA. Eighteen confirmed-human serum samples were tested by the newly developed particle agglutination assay system. The results were consistent with those from HIA, NTA and ELISA.

CONCLUSION

The Ha-Ny beads can be applicable to the development of a new JEV antibody-detection kit, which does not require specific laboratory facilities.

Sodium gradient-dependent transport of magnesium in rat ventricular myocytes

Cytoplasmic concentration of Mg(2+) ([Mg(2+)](i)) was measured with a fluorescent indicator furaptra in ventricular myocytes enzymatically dissociated from rat hearts (25 degrees C). To study Mg(2+) transport across the cell membrane, cells were treated with ionomycin in Ca(2+)-free (0.1 mM EGTA) and high-Mg(2+) (10 mM) conditions to facilitate passive Mg(2+) influx. Rate of rise of [Mg(2+)](i) due to the net Mg(2+) influx was significantly smaller in the presence of 130 mM extracellular Na(+) than in its absence. We also tested the extracellular Na(+) dependence of the net Mg(2+) efflux from cells loaded with Mg(2+). After [Mg(2+)](i) was raised by ionomycin and high Mg(2+) to the level 0.5-0.6 mM above the basal value ( approximately 0.7 mM), washout of ionomycin and lowering extracellular [Mg(2+)] to 1.2 mM caused rapid decline of [Mg(2+)](i) in the presence of 140 mM Na(+). This net efflux of Mg(2+) was completely inhibited by withdrawal of extracellular Na(+) and was largely attenuated by imipramine, a known inhibitor of Na(+)/Mg(2+) exchange, with 50% inhibition at 79 microM. The relation between the rate of net Mg(2+) efflux and extracellular Na(+) concentration ([Na(+)](o)) had a Hill coefficient of 2 and [Na(+)](o) at half-maximal rate of 82 mM. These results demonstrate the presence of Na(+) gradient-dependent Mg(2+) transport, which is consistent with Na(+)/Mg(2+) exchange, in cardiac myocytes.

18F-fluorodopa PET study of striatal dopamine uptake in the diagnosis of dementia with Lewy bodies

Using (18)F-fluorodopa PET and a constant 0.0062 influx rate in the putamen, dementia with Lewy bodies (n = 7) was distinguished from AD (n = 10) with a sensitivity of 86% and a specificity of 100%. A constant 0.0071 influx rate in the caudate yielded a sensitivity of 71% and a specificity of 100% for distinction of the two disorders. Despite a limited sample size, these findings suggest that assessing nigrostriatal dopaminergic function with (18)F-fluorodopa PET may be a useful diagnostic aid in cases of dementia with Lewy bodies while patients are alive.

Heparin bonding of the extracorporeal circuit reduces thrombosis during prolonged lung assist in goats

This study investigated whether an artificial membrane lung of nonmicroporous polyolefin hollow fibers bonded with heparin could prolong venoarterial extracorporeal lung assist (ECLA) with low dose systemic heparin in goats. We compared heparin bonded circuits (Carmeda Bioactive Surface, "HB" group, n = 5) with non heparin bonded circuits ("NHB" group, n = 5) in venoarterial ECLA (V-A ECLA) for 7 days. Activated coagulation time (ACT) was maintained at approximately 130 sec by systemic infusion of small doses of heparin in the HB group, and at 200-230 sec in the NHB group. Thrombus formation was assessed by visual examination of the circuit, and possible cerebral embolization of thrombi was observed from behavioral abnormalities of the animals. The mean heparin dose given during ECLA was 20.4 +/- 3.6 U/kg per hr in HB, and 50.9 +/- 14.2 U/kg per hr in NHB, significantly less in HB than NHB (p < 0.01). Blood gas changes across the oxygenator, bypass flow rate, platelet aggregation activity, platelet counts, fibrin monomer (FM) test, and antithrombin-III (AT-III) activity did not differ between the two groups. In HB, thrombi were fewer and no abnormal neurologic symptoms were observed during ECLA. Numerous thrombi were observed in all oxygenators with NHB. One NHB goat developed convulsions and cerebral hemorrhage on the 6th day of ECLA. Nonmicroporous polyolefin hollow fibers can be bonded with heparin. An artificial membrane lung constructed of these fibers showed good anticoagulation by decreased thrombus formation with a small dose of infused heparin.

Glucose uptake by individual skeletal muscles during running using whole-body positron emission tomography

The purpose of this study was to examine, by positron emission tomography (PET), the distribution of [18F]fluoro-deoxy-glucose ([18F]FDG) uptake by human muscles during 35 min of running. Thirteen healthy male subjects were studied, seven of whom participated in the exercise study. Running intensity was kept constant such that the subjects' heart rates were maintained at between 140 and 150 beats per minute. [18F]FDG [62.9 (14.8) MBq, mean (SD)] was injected after 15 min of running. PET imaging was started immediately after the running ended. The ratio of [18F]FDG uptake by muscles in runners to that in control subjects (r-c ratio) varied from three to six for the muscles of the foot and leg below the knee joint. The r-c ratio of the medial head of the gastrocnemius (MG) was higher than that of its lateral head (LG). The r-c ratio of the rectus femoris (RF) was lower than that of the other three muscles of the quadriceps femoris (QF). The r-c ratio of inactive muscles located above the waist was approximately 0.7. These results suggest that, during the moderate running of this study: (1) glucose uptake by muscles of the foot and leg below the knee joint clearly increases, (2) the r-c ratio differs significantly among the skeletal muscles, which act synergistically, and (3) glucose uptake by inactive skeletal muscles decreases.

Purification, characterization, and relation to bikunin of rat urinary trypsin inhibitors

Two forms of urinary trypsin inhibitor (UTI-1 and UTI-2) were purified from pooled urine of normal male rats to apparent homogeneity by salting out, affinity chromatography, gel filtration, and reverse-phase HPLC. UTIs-1 and 2 were shown to be thermostable glycoproteins with the respective molecular weights of 22,000 and 18,000 estimated by SDS-PAGE. These inhibitors combined with bovine trypsin in a 1:1 molar ratio: the Kd values were 2.5 x 10(-10) and 2.3 x 10(-10) M, respectively. Amino acid composition and sequence analysis indicated that UTI-1 corresponded to rat bikunin of which the amino acid sequence was deduced from a rat liver cDNA clone encoding alpha1-microglobulin [Lindqvist et al. (1992), Biochim. Biophys. Acta 1130, 63-67] except that the protein sequence seemed to lack C-terminal serine, and UTI-2 corresponded to UTI-1 lacking N-terminal 21 amino acid residues.

Transport of magnesium by two isoforms of the Na+-Ca2+ exchanger expressed in CCL39 fibroblasts

Cytoplasmic concentrations of Ca2+ ([Ca2+]i) and Mg2+ ([Mg2+]i) were measured with fluorescent indicators in CCL39 cells, a cell line established from Chinese hamster lung fibroblasts, transfected with complementary deoxyribonucleic acid (cDNA) of the Na+-Ca2+ exchanger isolated either from canine heart (NCX1) or from rat brain (NCX3). Raising extracellular [Mg2+] to 10 mM increased Mg2+ influx and the resultant change in [Mg2+]i (delta[Mg2+]i) was monitored with furaptra under Ca2+-free conditions. In control (vector-transfected) cells, delta[Mg2+]i at 45 min was similar with or without extracellular Na+ (130 mM or 0 mM) and when [Na+]i was raised by 1 mM ouabain treatment. delta[Mg2+]i in NCX1-transfected cells was attenuated significantly in the presence of 130 mM Na+, but became comparable to (or slightly larger than) that in control cells on either removal of extracellular Na+ or treatment with 1 mM ouabain. Cells expressing NCX3 showed an intermediate dependence of delta[Mg2+]i on Na+, probably reflecting a lower degree of expression of the exchanger protein. Extracellular Na+-dependent changes in [Ca2+]i (measured with fura-2 in the presence of extracellular Ca2+ and 10 microM ionomycin, a Ca2+ ionophore) were minimal in control cells, marked in the NCX1-transfected cells and intermediate in the NCX3-transfected cells. These results suggest that the Na+-Ca2+ exchanger (either NCX1 or NCX3) can transport Mg2+ and may play a role in the extrusion of magnesium from cells.

Total and prolonged filling of the lungs with Ringer's solution under extracorporeal lung assist (ECLA) in dogs

BACKGROUND

Massive alveolar lavage has been used clinically to remove materials accumulated in the alveoli. Recently, filling the lungs with oxygenated perfluorochemical (total liquid ventilation) has been investigated. However, effects of complete and prolonged filling of bilateral lungs with aqueous fluid, such as saline or Ringer's solution, has not been evaluated, although it is possible to sustain gas exchange without the natural lung by using extracorporeal circulation and an artificial lung (extracorporeal lung assist: ECLA). It is also not known whether the lung can recover gas exchange ability after prolonged fluid filling.

METHODS

Normal mongrel dogs were endotracheally intubated under general anesthesia and mechanically ventilated. After initiation of venoarterial ECLA, warmed lactated Ringer's solution was instilled into the lungs through the endotracheal tube, and the lungs were completely filled at a hydrostatic pressure of 15 cmH2O (fluid-filled group: group F). After the lungs were filled for 4 h, the fluid was drained and ventilation was re-instituted. ECLA, then mechanical ventilation was gradually weaned within 24 h after fluid drainage. In control group (group C), dogs were kept apneic for 4 h with their lungs inflated at an airway pressure of 15 cmH2O with air.

RESULTS

Transient hypoxemia occurred during fluid filling but every dog could be weaned from ECLA and mechanical ventilation to spontaneous respiration. The average rate of fluid absorption from the lung during fluid filling was 4.2+/-1.8 ml kg(-1) h(-1). After fluid drainage and restart of mechanical ventilation, bilateral lungs were expanded and well aerated. Total static respiratory system compliance (static compliance) remained unchanged even after fluid filling, and the weight of the lung water did not increase significantly compared to that in group C. Total urine volume was significantly increased in group E Histologically, alveolar structures were preserved and no interstitial edema or bleeding was seen in either group.

CONCLUSION

Complete filling of the bilateral lungs for 4 h with lactated Ringer's solution under ECLA causes no deterioration in gas exchange or static compliance in normal dogs, although transient hypoxemia occurs during fluid filling.

[An electrosurgical burn possibly caused by radio-frequency leakage current through a stainless forceps]

A 73-year-old operated female got burned on the skin probably nipped by a stainless forceps. An active cable had been coiled around the forceps throughout the surgery. Consequently, an electrosurgical burn was possibly caused by radio-frequency leakage current (RFLC) via the metallic forceps. The authors experimentally coiled active cables around a stainless forceps, then measured RFLC produced by four kinds of electrosurgical units in the modes of cutting, blend, coagulation, spray coagulation, and argon beam coagulation. The maximum of RFLC was 81 mA, which met the JIS or IEC standard (150 mA). However, the critical current density causing electrosurgical burns (> 25-70 mA.cm-2) was suggested to be produced by RFLC through a metallic forceps with a small diameter. Of great importance is not to coil active cables around electro-conductible instruments during surgery.

Extensive lymphopenia due to apoptosis of uninfected lymphocytes in acute measles patients

Infection with measles virus induces a transient immunosuppression, which occasionally results in fatal opportunistic infections. To obtain fundamental information about the mechanism, we examined peripheral blood mononuclear cells (PBMC) from acute measles patients aged from infants to 35 years old, obtained at various times from incubation periods to 103 days after onset of rash, for the number of lymphocyte subsets by flowcytometry. The data were analyzed for relationships between aging of the patients and the severity of immunosuppression. In classical measles cases, infected lymphocytes detected as a minor population during the incubation period disappeared soon after onset of rash, whereas in the cases of serious illness, the infected cells persisted longer after the rash. At the onset of rash, remarkable lymphopenia had already occurred in all measles cases with reduction in cell numbers of CD4+ T cells, CD8+ T cells, B cells, neutrophils, and monocytes. In contrast, natural killer (NK) cells were increased in number and activated, which might be a response compensatory for the lymphopenia. Apoptosis-associated molecules such as CD95(Fas) and TNF-related apoptosis-inducing ligand-receptor (TRAIL-R) were highly expressed on the cell surface of most surviving non-infected lymphocytes, and DNA fragmentation was also observed upon incubation in vitro. These results suggested that the profound lymphopenia was primarily due to extended death of non-infected blood cells caused by apoptosis. The severity and duration of the lumphopenia were age-dependent; less severe in young children whereas much severer in infants under one year of age as well as adolescents and adults. From these results, it was suggested that remarkable lymphopenia due to apoptosis of uninfected cells is one of the principal causes for immunosuppression induced by measles virus infection, and is correlated with the age-dependent severity of the disease.

Recovery of pathogenic measles virus from cloned cDNA

Reverse genetics technology so far established for measles virus (MeV) is based on the Edmonston strain, which was isolated several decades ago, has been passaged in nonlymphoid cell lines, and is no longer pathogenic in monkey models. On the other hand, MeVs isolated and passaged in the Epstein-Barr virus-transformed marmoset B-lymphoblastoid cell line B95a would retain their original pathogenicity (F. Kobune et al., J. Virol. 64:700-705, 1990). Here we have developed MeV reverse genetics systems based on the highly pathogenic IC-B strain isolated in B95a cells. Infectious viruses were successfully recovered from the cloned cDNA of IC-B strain by two different approaches. One was simple cotransfection of B95a cells, with three plasmids each encoding the nucleocapsid (N), phospho (P), or large (L) protein, respectively, and their expression was driven by the bacteriophage T7 RNA polymerase supplied by coinfecting recombinant vaccinia virus vTF7-3. The second approach was transfection with the L-encoding plasmid of a helper cell line constitutively expressing the MeV N and P proteins and the T7 polymerase (F. Radecke et al., EMBO J. 14:5773-5784, 1995) on which B95a cells were overlaid. Virus clones recovered by both methods possessed RNA genomes identical to that of the parental IC-B strain and were indistinguishable from the IC-B strain with respect to growth phenotypes in vitro and the clinical course and histopathology of experimentally infected cynomolgus monkeys. Thus, the systems developed here could be useful for studying viral gene functions in the context of the natural course of MeV pathogenesis.

Versatility of the accessory C proteins of Sendai virus: contribution to virus assembly as an additional role

The P/C mRNA of Sendai virus (SeV) encodes a nested set of accessory proteins, C', C, Y1, and Y2, referred to collectively as C proteins, using the +1 frame relative to the open reading frame of phospho (P) protein and initiation codons at different positions. The C proteins appear to be basically nonstructural proteins as they are found abundantly in infected cells but greatly underrepresented in the virions. We previously created a 4C(-) SeV, which expresses none of the four C proteins, and concluded that the C proteins are categorically nonessential gene products but greatly contribute to viral full replication and infectivity (A. Kurotani et al., Genes Cells 3:111-124, 1998). Here, we further characterized the 4C(-) virus multiplication in cultured cells. The viral protein and mRNA synthesis was enhanced with the mutant virus relative to the parental wild-type (WT) SeV. However, the viral yields were greatly reduced. In addition, the 4C(-) virions appeared to be highly anomalous in size, shape, and sedimentation profile in a sucrose gradient and exhibited the ratios of infectivity to hemagglutination units significantly lower than those of the WT. In the WT infected cells, C proteins appeared to colocalize almost perfectly with the matrix (M) proteins, pretty well with an external envelope glycoprotein (hemagglutinin-neuraminidase [HN]), and very poorly with the internal P protein. In the absence of C proteins, there was a significant delay of the incorporation of M protein and both of the envelope proteins, HN and fusion (F) proteins, into progeny virions. These results strongly suggest that the accessory and basically nonstructural C proteins are critically required in the SeV assembly process. This role of C proteins was further found to be independent of their recently discovered function to counteract the antiviral action of interferon-alpha/beta. SeV C proteins thus appear to be quite versatile.