Search

Background: Klebsiella pneumoniae (Kpn) strains are a leading cause of hospital-acquired infections, including ventilator-associated pneumonia. Resistance to antibiotics, biofilm formation, and the production of certain fimbriae play an important role in the pathogenesis. Aim: We investigated the genetic relatedness, antibiotic resistance, virulence potential, and ability to form biofilms of Kpn strains isolated from hospital-acquired infections (n = 76). Strains were isolated at three major hospitals serving the largest metropolitan urban area in Mexico City, Mexico. Results: Enterobacterial repetitive intergenic consensus (ERIC)–PCR demonstrated that clonal groups predominate in each hospital. Selected strains chosen from clonal groups (n = 47) were multidrug resistant (MDR, 83%), although the majority (∼70%) were susceptible to carbapenems. All strains produced robust biofilms on abiotic surfaces, and ∼90% harbored adhesin genes fimH, mrkA, and ecpA. The ultrastructure of biofilms was further studied by high-resolution confocal microscopy. The average height of Kpn biofilms on abiotic surfaces was ∼40 μm. We then assessed formation of biofilms on human lung cells, as a surrogate of lung infection. While Kpn strains formed robust biofilms on abiotic surfaces, studies on lung cells revealed attachment to human cells but scarce formation of biofilms. Gene expression studies revealed a differential temporal expression of an adhesin (ecpA) and a capsule (galF) gene when biofilms were formed on different substrates. Conclusions: Kpn strains isolated from nosocomial infections in Mexico City are MDR, although the majority are still susceptible to carbapenems and form more robust biofilms on polystyrene in comparison to those formed on human cells.

Streptococcus pneumoniae is a main cause of child mortality worldwide, but strains also asymptomatically colonize the upper airways of most children and form biofilms. Recent studies have demonstrated that ∼50% of colonized children carry at least two different serotypes (i.e., strains) in the nasopharynx; however, studies of how strains coexist are limited. In this work, we investigated the physiological, genetic, and ecological requirements for the relative distribution of densities, and spatial localization, of pneumococcal strains within biofilm consortia. Biofilm consortia were prepared with vaccine type strains (i.e., serotype 6B [S6B], S19F, or S23F) and strain TIGR4 (S4). Experiments first revealed that the relative densities of S6B and S23F were similar in biofilm consortia. The density of S19F strains, however, was reduced to ∼10% in biofilm consortia, including either S6B, S23F, or TIGR4, in comparison to S19F monostrain biofilms. Reduction of S19F density within biofilm consortia was also observed in a simulated nasopharyngeal environment. Reduction of relative density was not related to growth rates, since the Malthusian parameter demonstrated similar rates of change of density for most strains. To investigate whether quorum sensing (QS) regulates relative densities in biofilm consortia, two different mutants were prepared: a TIGR4Δ luxS mutant and a TIGR4Δ comC mutant. The density of S19F strains, however, was similarly reduced when consortia included TIGR4, TIGR4Δ luxS , or TIGR4Δ comC . Moreover, production of a different competence-stimulating peptide (CSP), CSP1 or CSP2, was not a factor that affected dominance. Finally, a mathematical model, confocal experiments, and experiments using Transwell devices demonstrated physical contact-mediated control of pneumococcal density within biofilm consortia. IMPORTANCE Streptococcus pneumoniae kills nearly half a million children every year, but it also produces nasopharyngeal biofilm consortia in a proportion of asymptomatic children, and these biofilms often contain two strains (i.e., serotypes). In our study, we investigated how strains coexist within pneumococcal consortia produced by vaccine serotypes S4, S6B, S19F, and S23F. Whereas S6B and S23F shared the biofilm consortium, our studies demonstrated reduction of the relative density of S19F strains, to ∼10% of what it would otherwise be if alone, in consortial biofilms formed with S4, S6B, or S23F. This dominance was not related to increased fitness when competing for nutrients, nor was it regulated by quorum-sensing LuxS/AI-2 or Com systems. It was demonstrated, however, to be enhanced by physical contact rather than by a product(s) secreted into the supernatant, as would naturally occur in the semidry nasopharyngeal environment. Competitive interactions within pneumococcal biofilm consortia regulate nasopharyngeal density, a risk factor for pneumococcal disease.

Identification of Streptococcus pneumoniae and its more than 90 serotypes is routinely conducted by culture and Quellung reactions. Quantitative polymerase chain reactions (qPCRs) have been developed for molecular detection, including a pan-pneumococcus lytA assay, and assays targeting 79 serotypes. Reactions require genomic DNA from every target to prepare standards, which can be time consuming. In this study, we have developed a synthetic DNA molecule as a surrogate for genomic DNA and present new single-plex qPCR reactions to increase molecular detection to 94 pneumococcal serotypes. Specificity of these new reactions was confirmed with a limit of detection between 2 and 20 genome equivalents/reaction. A synthetic DNA (NUversa, ∼8.2 kb) was then engineered to contain all available qPCR targets for serotyping and lytA. NUversa was cloned into pUC57-Amp-modified to generate pNUversa (∼10.2 kb). Standards prepared from pNUversa and NUversa were compared against standards made out of genomic DNA. Linearity [NUversa (R2 > 0.982); pNUversa (R2 > 0.991)] and efficiency of qPCR reactions were similar to those utilizing chromosomal DNA (R2 > 0.981). Quantification with plasmid pNUversa was affected, however, whereas quantification with synthetic NUversa was comparable to that of genomic DNA. Therefore, NUversa may be utilized as DNA standard in single-plex assays of the currently known 94 pneumococcal serotypes., NUversa is a synthetic DNA molecule that can be utilized as a ‘universal’ standard in virtually all serotype-specific qPCR assays for pneumococcus published in the literature.

Stepped impedance resonators (SIRs) are composed of multiple transmission lines with different characteristic impedances and can control higher-order mode resonance frequencies. Here, identification codes from a resonator were systematically generated by utilizing these properties and introducing symmetric multimode SIRs composed of transmission lines of uniform length. In the other direction, resonator codes were identified by detecting their higher-order mode resonance frequencies. This paper describes these resonance properties and experimental results for multimode SIRs and presents a frequency detection method using electromagnetic probes. The experimental data show that the proposed method is applicable to a chipless RFID tag system.

Streptococcus pneumoniae is both a commensal and a major pathogen that causes invasive disease in people of all ages. The introduction of serotype-specific pneumococcal vaccines has reduced the burden of disease but has also led to replacement with new strains; thus, serotyping remains important for vaccine-related disease surveillance. Conventional serotyping methods are laborious and expensive. We developed an easy-to-perform genotypic TaqMan array card (TAC) to identify S. pneumoniae strains, including lytA -based sequences, and 53 sequence-specific PCRs to identify 74 serotypes/serogroups covering all current vaccine types as well as prevalent nonvaccine types. The TAC method was evaluated on 146 clinical S. pneumoniae isolates and 13 nonpneumococcal species that naturally inhabit the upper respiratory tract and yielded 97% (142/146) sensitivity and 100% (13/13) specificity versus results of standard Quellung serotyping. The calculated limit of detection was 20 to 200 fg (∼8 to 84 genome equivalents) per reaction. On 23 blinded nasopharyngeal specimens that were pneumococcus culture positive, the TAC pan-pneumococcus lytA assay was positive in 21 (91% sensitivity versus culture). On TAC lytA -positive specimens, a serotype result was obtained on 86%, and the result was 95% accurate versus the subsequent culture's Quellung result. TAC also detected mixed serotypes in two specimens where Quellung detected only the predominant serotype. This TAC method yields fast and comprehensive serotyping compared to the standard method and may be useful on direct specimens.

A UWB impulse array antenna (IAA) utilizing a novel electrical scanning system with tapped delay lines is proposed and its usefulness is experimentally verified. The experimental antenna is composed of impulse generators installed in each antenna element and tapped delay lines used for creating transmitting trigger signals, which is a simple circuit configuration. It is shown that the output phase of the transmitting wave can be controlled by controlling the period of the trigger signal, and beam direction can be controlled from -30deg to +30deg by changing the trigger frequency from Fc -2kHz to Fc+2kHz. Evaluation of this antenna as a short range radar is carried out and distance resolution of 25cm and angle resolution below 10deg are obtained.

We examined associations of serotypes with multilocus sequence typing (MLST) data for 7 housekeeping genes and the genotype concerning penicillin resistance based on penicillin-binding protein (PBP) alterations in Streptococcus pneumoniae isolates from children with meningitis. From throughout Japan, we collected 115 pneumococcal isolates from the cerebrospinal fluid of patients 15 years old or younger from January 2007 to December 2009. We then carried out serotyping, MLST, and genotypic classification. Isolates included 24 serotypes and 52 sequence types (STs) according to MLST, of which 18 were novel. The 4 predominant serotypes included a variety of STs: 14 STs in serotype 6B (n = 24), 2 STs in 19F (n = 17), 6 STs in 23F (n = 14), and 5 STs in 14 (n = 11). Resistance genotypes included 6 types: 44.3% for gPRSP (pbp1a + 2x + 2b), 13.9% for gPISP (pbp1a + 2x), 9.6% for gPISP (pbp2x + 2b), 19.1% for gPISP (pbp2x), 3.5% for gPISP (pbp2b), and 9.6% for gPSSP. Interestingly, the most prevalent serotype of 6B included 7 newly identified STs and a variety of genotypes for resistance. STs in serotypes 23F and 14 were highly diverse, but not in 19F. These results suggest that various genetic elements in S. pneumoniae might be intrinsically susceptible to genetic mutations and recombination, with acceleration of emergence reflecting selection pressures such as antibiotic overuse.

Bacterial meningitis is a serious problem in pediatric clinics and, therefore, needs urgent and empirical chemotherapy. We investigated 1,116 cases of empirical chemotherapy of patients aged older than 4 months from 1997 through 2008 by sending questionnaires. A single antibiotic treatment was carried out in less than 30% of the cases throughout the years, whereas the combination of two antibiotics had been practiced in more than 70% of the cases. The main antibiotics used were cephalosporins, carbapenems, and ampicillin. Combinatory use of ampicillin and cephalosporin was carried out in 74.7-82.7% of cases in 1997-2000, but sharply declined thereafter to 0-13.8% in 2004-2008. However, the combination of carbapenem and cephalosporin compensated for the decline, increasing from 3.8-6.6% in 1998-1999 to 79.5-89.9% in 2005-2008. The breakdown in the use of cephalosporins, carbapenems, and ampicillin in two-drug combinatory therapy was as follows. (i) Use of cefotaxime was 61.8-75.3% in 1997-2001, but decreased to nearly 50%, equivalent to the level of ceftriaxone use in 2003-2008. (ii) Use of ampicillin dropped from 74.7-92.3% in 1997-2000 to 4.6% in 2008, and this decreased level was compensated for by the use of carbapenems. Overall, combinatory chemotherapy of the third-generation cephalosporins and carbapenems seems to be practical. The discussion in this report includes the difference between Japan and the United States in the prevalence of the causative agents and the use of antibiotics. These studies provide information on trends in the treatment of children's meningitis in Japan and will be useful for the design of future empirical chemotherapy.

We surveyed pediatrics bacterial meningitis epidemiology from January 2007 to December 2008 in Japan, with the following results: Cases numbered 287-160 male and 127 female-equivalent to 1.54-1.62 of 1,000 pediatric hospitalization per year. Children under 1-year-old accounted for the highest number of cases, which decreased with increasing age. Haemophilus influenzae was the most common cause of infection, followed by Streptococcus pneumoniae, group B streptococcus (GBS), and Escherichia coli. GBS and E. coli were major pathogens in children under 4 months of age, while H. influenzae and S. pneumoniae mainly accounted for those over 4 months of age. Susceptibility tests showed that 51% of H. influenzae isolates and 56.5% of S. pneumoniae isolates in 2008 were drug-resistant. Ampicillin combined with cephem antibiotics effective against GBS, E. coli, and Listeria, were mainly used to initially treat those under 4 months of age. In those over 4 months of age, carbapenem antibiotics are effective against PRSP and cephem antibiotics against H. influenza.

Limited use of linezolid for treating methicillin-resistant Staphylococcus aureus (MRSA) infection was approved in Japan in 2006. We report here the status of linezolid-resistant MRSAs in Japan. Eleven linezolid-resistant clinical isolates from 11 patients at six hospitals were collected from 2006 through 2008. The minimal inhibitory concentration (MIC) of linezolid in these strains varied from 8 to 64 μg/ml. All strains had at least one G2576T mutation in the chromosomal gene(s) encoding domain V of the 23S ribosomal RNA (rRNA). Chromosomal DNA encoding five copies of the domain V region was analyzed by polymerase chain reaction (PCR). Strains with the linezolid MICs of 64, 32, 16, and 8 μg/ml had the G2576T mutation(s) in four, three (or four), two, and one copy of the 23S rRNA genes, respectively. These results suggest that the level of linezolid resistance seems to be roughly correlated with the number of mutations in the genes encoding 23S rRNA. DNA samples from all 11 strains were subjected to pulsed-field gel electrophoresis and were classified into seven independent clones having >92% identity. Among the 11 patients, five had been treated with linezolid and the remainder, in two hospitals, had no history of prior linezolid use. The results suggested possible nosocomial infections by linezolid-resistant MRSA.

Streptococcus pneumoniae globally kills more children than any other infectious disease every year. A prerequisite for pneumococcal disease and transmission is colonization of the nasopharynx. While the introduction of pneumococcal conjugate vaccines has reduced the burden of pneumococcal disease, understanding the impact of vaccination on nasopharyngeal colonization has been hampered by the lack of sensitive quantitative methods for the detection of >90 known S. pneumoniae serotypes. In this work, we developed 27 new quantitative (q)PCR reactions and optimized 26 for a total of 53 qPCR reactions targeting pneumococcal serotypes or serogroups, including all vaccine types. Reactions proved to be target-specific with a limit of detection of 2 genome equivalents per reaction. Given the number of probes required for these assays and their unknown shelf-life, the stability of cryopreserved reagents was evaluated. Our studies demonstrate that two-year cryopreserved probes had similar limit of detection as freshly-diluted probes. Moreover, efficiency and limit of detection of 1-month cryopreserved, ready-to-use, qPCR reaction mixtures were similar to those of freshly prepared mixtures. Using these reactions, our proof-of-concept studies utilizing nasopharyngeal samples (N=30) collected from young children detected samples containing ≥2 serotypes/serogroups. Samples colonized by multiple serotypes/serogroups always had a serotype that contributes at least 50% of the pneumococcal load. In addition, a molecular approach called S6-q(PCR)2 was developed and proven to individually detect and quantify epidemiologically-important serogroup 6 strains including 6A, 6B, 6C and 6D. This technology will be useful for epidemiological studies, diagnostic platforms and to study the pneumobiome.

Background Identification of Streptococcus pneumoniae (Spn) and its more than 90 serotypes is routinely conducted by culture and Quellung reactions. Quantitative (q)PCR reactions have been developed for molecular detection, including a pan-Spn lytA assay, and assays targeting 78 serotypes. Reactions require genomic DNA from every target to prepare standards, which can be time consuming. In this study we have developed a synthetic DNA molecule as a surrogate for genomic DNA and present new single-plex qPCR reactions to increase molecular detection to 94 pneumococcal serotypes. Methods Single-plex qPCR reactions (N = 11) that detect 16 pneumococcal serotypes/serogroups were developed and concentration of primer and probe optimized to obtain a recommended efficiency between 90 and 110%. Specificity for the target serotype/serogroup of these new reactions was investigated using a collection of strains belonging to our laboratory and strains kindly donated by the “StrepLab” at CDC. A synthetic DNA (NUversa, ~8.2 kb) was then engineered to contain all available qPCR targets for serotyping and lytA. NUversa was cloned into pUC57-Amp-modified to generate pNUversa (~10.2 kb). Standards prepared from pNUversa and NUversa were compared against standards made out of genomic DNA. Results Specificity of these new reactions was confirmed, and after optimization, the obtained limit of detection (LOD) was between 2 and 20 genome equivalents/reaction. Molecular studies demonstrated that linearity [NUversa (R2>0.982); pNUversa (R2>0.991)] and efficiency of qPCR reactions using synthetic DNA were similar to those utilizing chromosomal DNA (R2>0.981). Quantification, however, with plasmid pNUversa (Y-Int=43.0 ± 1.12) was affected whereas that using synthetic NUversa (Y-Int=40.3 ± 1.08) was comparable to genomic DNA (Y-Int=39.9 ± 0.62). Conclusion We validated new single-plex reactions that, together with published qPCR reactions, now make possible to detect and quantify 94 pneumococcal serotypes/serogroups. NUversa can be utilized as a control in most, if not all, published single-plex qPCR reactions, for the identification (i.e., detection), and quantification (i.e., genome equivalents) of pneumococcal serotypes. Disclosures All authors: No reported disclosures.

A UWB through-wall radar using novel beam scanning array antenna previously proposed by the authors is described. This antenna scanning system has two new technologies. First, each antenna element is equipped with an impulse generator. Second, the time control between the antenna elements is realized by using tapped delay lines and by transmitting trigger signals. Based upon above technology, experimental UWB through-wall radar having beam scanning capability is designed and constructed. The fabricated radar has compact size and light weight and is easy to use. The measurement results show excellent space resolution as a through-wall radar.

Fuminori Sakai1, Hideaki Hanaki2, Kazunari Barada4, Yuriko Hirao1, Takashi Inamatsu5, Taiji Nakae2, Keisuke Sunakawa31Laboratory of Infectious Diseases, Graduate School of Infection Control Sciences, 2Research Center for Anti-Infectious Drugs, Kitasato Institute, 3Department of Research Project Studies, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan; 4Department of Pharmacy, General Ota Hospital, Society of Health Insurance of Fuji Heavy Industries Ltd, Gunma, Japan; 5Department of Infectious Diseases, Tokyo Metropolitan Geriatric Hospital, Tokyo, JapanAbstract: We analyzed 218 strains of methicillin-resistant Staphylococcus aureus (MRSA) isolated from the septicemia patients in a geriatric hospital for 25 years. These strains were classified into 11 major DNA types, A through K, and 27 minor types. The strains belonging to group A and B isolated before 1990 were susceptible to imipenem (IPM), fluoroquinolone, and most other antibiotics tested, except that they were markedly resistant to gentamicin. Strains mostly isolated in 1985 and thereafter were classified into group C through K, and they were mainly resistant to IPM, fluoroquinolones, and clindamycin. Analysis of the MRSA marker gene, staphylococcal cassette chromosome mec (SCCmec), of these strains revealed that the strains in groups A and B had mainly type IV and type I, respectively, and that strains in groups C through J had mainly type II. These results suggested that the strains holding type II SCCmec were resistant to IPM, fluoroquinolone, and clindamycin and they were dominant-resistant type after late 1980s. The antibiotic resistance profiles of MRSA dramatically changed during late 1980s, and these were correlated with the SCCmec types. The lesson from this study would be that consistent execution of surveillance study is needed to update the resistant profiles.Keywords: methicillin-resistant Staphylococcus aureus, DNA typing, antibiotic resistance, survey, geriatric hospital

In this paper, we present a newly developed UWB array antenna adopting a novel electrical scanning system. This antenna was realized by introducing two new technologies. First, each antenna element is equipped with an impulse generator. Second, the phase control between the antenna elements is realized by tapped delay lines and transmitting trigger signals. An experimental UWB array antenna with 16 elements has been designed and fabricated. The measurement results showed excellent performance of the antenna. Thus, it is expected that this UWB antenna system will contribute to performance improvement, compact size and cost reduction of UWB radar systems such as obstacle detectors and anticollision sensors. Index Terms — UWB radar, array antenna, electrical scanning antenna, beam steering, phased array, delay line.

In 2008 we isolated methicillin-resistant Staphylococcus aureus (MRSA) from an 11-month-old Japanese girl who lived in Saitama, Japan, and suffered from cellulitis of the lower thigh and sepsis. The MRSA (strain NN47) belonged to multilocus sequence type (ST) 8 and exhibited spa363 (t024), agr1, staphylococcal cassette chromosome mec (SCCmec) type IVa, and coagulase type III. It was positive for Panton-Valentine leukocidin (PVL) and the arginine catabolic mobile element (ACME). Pulsed-field gel electrophoresis (PFGE) demonstrated that the MRSA was the USA300 clone, which is the predominant community-acquired MRSA (CA-MRSA) in the US. Strain NN47 was divergent, in terms of the spa type and patterns of PFGE and plasmids, from the USA300-0114 type strain or USA300 strain NN36, previously isolated from a visitor (Indian girl) from the US. Strain NN47 was resistant to erythromycin, in addition to beta-lactam agents (e.g., oxacillin). These data demonstrate the first emergence of the USA300 clone in Japanese children who have never been abroad and have had no contact with foreigners (and therefore, the first USA300 spread in Japan), and also emergence of multiple divergent strains of the USA300 clone in Japan. Because the USA300 clone is highly transmissible and virulent, surveillance of the USA300 clone is needed.

The suppressive effect of dipyridamole on the proteinuria of aminonucleoside nephrosis and protamine-induced proteinuria, was investigated. Male Wistar rats were given puromycin aminonucleoside (80 mg/kg s.c.) or protamine sulfate (20 mg/kg i.v.), and the urine was collected in metabolic cages. The content of proteins in the urine was determined by using a continuous gradient microgel electrophoresis procedure. Dipyridamole (20 mg/kg p.o.) suppressed the excretion of albumin and proteins larger than albumin (HMP) in aminonucleoside nephrosis. But the excertion of proteins smaller than albumin (LMP) was not affected by dipyridamole. Dipyridamole also suppressed the excertion of HMP in protamine-induced proteinuria, though the excretion of albumin and LMP was not affected. Puromycin aminonucleoside and protamine sulfate were known to cause renal glomerular epithelial changes referred to as "fusion" of foot processes. Since dipyridamole was effective in suppressing the both types of proteinuria, this drug was considered to improve the damaged renal glomerular barrier for plasma proteins.

In order to investigate the presence of renal kallikrein, the localization of kallikrein-like proteolytic activity along a single nephron was determined in rabbits. Single nephrons were dissected into 8 segments under a microscope. Activity was fluorometrically measured with two different substrates (benzoyl-L-arginine ethyl ester: BAEE and prolyl-phenylalanyl-arginine-methylcoumarin amide: MCA). Proteolytic activity could be detected in the early (S1), the middle (S2), and the terminal (S3) portions of the proximal tubule and in the granular portion of the distal tubule (DCTg). With MCA, the specific activity in S1, S2, S3 and DCTg was 0.77 +/- 0.08, 0.28 +/- 0.10, 0.13 +/- 0.05, and 0.27 +/- 0.05 pmoles/microgram/min, respectively. The activity in DCTg was inhibited by aprotinin but that in the proximal tubules was not inhibited. No activity was found in the glomerulus, the thick ascending limb of Henle's loop, the bright portion of the distal tubule, and the light portion of the cortical collecting tubule. The inhibition of the activity by aprotinin in DCTg suggests that intrarenal kallikrein could be localized only in DCTg.

The ability of a microsomal enzyme, glucose dehydrogenase (hexose 6-phosphate dehydrogenease) to supply NADPH to the microsomal electron transport system, was investigated. Microsomes could perform oxidative demethylation of aminopyrine using microsomal glucose dehydrogenase in situ as an NADPH generator. This demethylation reaction had apparent Km values of 2.61 X 10(-5) M for NADP+, 4.93 X 10(-5) m for glucose 6-phosphate, and 2.14 X 10(-4) m for 2-deoxyglucose 6-phosphate, a synthetic substrate for glucose dehydrogenase. Phenobarbital treatment enhanced this demethylation activity more markedly than glucose dehydrogenase activity itself. Latent activity of glucose dehydrogenase in intact microsomes could be detected by using inhibitors of microsomal electron transport, i.e. carbon monoxide and p-chloromercuribenzoate (PCMB), and under anaerobic conditions. These observations indicate that in microsomes the NADPH generated by glucose dehydrogenase is immediately oxidized by NADPH-cytochrome c reductase, and that glucose dehydrogenase may be functioning to supply NADPH.

Summary Intra-renal distribution of 25-hydroxyvitamin D3(25-OH-D3)-lα-hydroxylase activity was studied in single nephron segments prepared from New Zealand White rabbit fetuses (26th to 28th day of gestation). Fetal kidneys were treated with collagenase and the isolated nephrons were micro-dissected into five differrent parts. Each segment of the nephron was incubated with [3H]-25-OH-D3. Metabolites of [3H]-25-OH-D3 were separated by high performance liquid chromatography. The results show that 25-OH-D3-1α-hydroxylase activity is localized only in the proximal tubule and that the pars recta of proximal tubule possesses higher activity than the proximal convoluted tubule. The findings indicate that the major and probably exclusive site of 1α,25-(OH)2-D3 synthesis is the proximal tubule not only in birds, as reported by Brunette et al. (8) , but also in mammals.

(1) Cardiovascular reactivity, 16 to 28 hours after bilateral nephrectomy was determined in rats by obtaining the dose-blood pressure-response curve in order to avoid the vertical bias.(2) Bilateral nephrectomy did not increase cardiovascular reactivity to pressor agents (angiotensin and norepinephrine) in rats anesthetized by pentobarbital or anesthetized and treated by pentolinium, a ganglion blocking agent.(3) In pithed animals without anesthesia nephrectomy augmented slightly but definitely the response to pressor agents.(4) Further elimination of the neural innervation in pithed animals by administration of bretylium, an adrenergic neurone blocking agent, atropine, and pentolinium, also resulted in an increased response to angiotensin after bilateral nephrectomy.(5) But it is inadequate to explain the marked augmentation of response to renin after nephrectomy only by the slight increase in response to angiotensin. Response to renin was markedly augmented in pithed animals as well as under usual condition.(6) Bilateral nephrectomy diminished cardiovascular reactivity to depressor agents (acetylcholine, adenosine triphosphate and histamine).(7) Angiotensinogen in the plasma increased 4 times more after bilateral nephrectomy. This is the main cause of marked augmentation in response to renin.(8) The claim that, if angiotensinogen is already in excess, a further increase in its concentration would not lead to an increased production of angiotensin was denied experimentally and theoretically.

(1) The renin-angiotensinogen reaction in the rat was examined in detail under various conditions of pH and temperature. Angiotensinase activity in the kidney extract and the plasma was also determined.(2) pH-activity curves of angiotensinases in the plasma, red cells, and kidney extracts were determined. Angiotensinases in the kidney tissue had different pH-characteristics from those of the plasma or red cells.(3) Incubation of the aid-treated extract with the heparinized plasma resulted in the maximum formation of angiotensin at pH 6.5, regardless of the presence of EDTA.(4) At pH 5.5 formation of angiotensin continued to increase until 40min., and then formed a plateau, by incubating the acid- and alkaline-treated extract of 1/30 concentration at 37°C.(5) At pH 6.5 formation of angiotensin reached the maximum after 20 to 40min., and then decreased slightly, by incubating the acid- treated extract of 1/30 concentration at 37°C with 3.3×10-3 M EDTA.(6) At pH 8.0 incubation of the acid-treated extract at 20°C resulted in a linear increase of angiotensin formation until 80min.(7) Formation of angiotensin with various concentrations of the kidney extracts was determined under the above 3 conditions, where the effect of angiotensinases was relatively low and formation of angiotensin increased with the incubation time for a sufficient length.(8) The reaction constants (K) calculated from the above results had a linear relationship with a wide range of concentrations of kidney extract at pH 8.0.(9) Incubation of the acid-treated kidney extract with the plasma at pH 8.0 and 20°C for 30min. gave a more reliable method for the determination of renin in rat kidney.

During and after the war, many clinicians in Japan witnessed unexpected febrile reactions following intravenous injections of the oficinal products of glucose-solution in ampuls which were apparently made to conform to the pharmacopoeia requirements. Main purpose of our present investigations is to contribute to solve this common problem in the postwar time. So far as the pharmacopoeial products of glucose-powder are concerned, the important role of pyrogens as a cause of clinical pyrexia cannot be ignored, as shown in the conclusion of our previous report (1). We have no doubt of the fact that certain moulds and yeasts as well as bacteria existing in glucose-powders are capable to produce pyrogens under a suitable humidity and temperature, and presumably even in a “dry” state of the powders. In the experiments regarding glucose-powder, as shown in the previous report, pyrogens were accompanied generally with pyrogen-producing microbes in experimental materials, and then they could be easily separated from microbes in case of necessity. Now, in the present attempt to determine the pyrogenecity of glucose-solution in ampuls, we must dear with a rather more involved matter, since all the samples to be adopted here are free from any mycologically or bacteriologically positive evidence as to the possible presence of microbes in them. The mode of clinical occurrences of febrile reactions following glucose injections seemed to be sporadic, so far as the commercial solutions sealed in ampuls are concerned. It was sometimes reported that when an ampul packed in a box proved pyrogenetic to a patient, some of the rest of the ampuls packed with it in the same box did not always yield a similar reaction to other patients. Aside from pyrogenetic microbes, we have to determine whether or not pyrogens are common in all ampuls of the same lot-number. Supposing the amount of pyrogens contained to be small, susceptibilities of the patient would play an important part to exhibit an equivocal phenomena concerning febrile reactions in clinics. This is also one of the questions to be solved in our experimental investigations.

1. The electrical properties of the proximal tubular cells were studied in the newt kidney by using microelectrode techniques.2. The surface membrane of the tubular cells behaved like a simple resistor when a minute current was applied intracellularly. The changes in the transmembrane potential was linearly proportional to the strength of applied current and there was neither the rectification nor the self-generative response within. a wide range of current strength.3. The potential change caused by the intracellular application of current spread over considerable distances along the longitudinal axis of the tubule. The tubular wall, thus, behaved like a core conductor.4. Application of the simple core conductor theory to the model of the tubular wall gave the values of 400μ for the space constant, 3.1×105Ωfor the effective resistance, 836Ωcm2 for the specific resistance of the surface membrane and 625Ωcm for the specific resistance of the core (cytoplasm including intercellular membranes).5. A comparison of the surface membrane resistance to the transtubular resistance suggests that there are significant extracellular shunt paths for electrolytes within the tubular wall. The leaky nature of the proximal segment was ascribed to the presence of such shunt paths.

Schon fruher haben Gibbs u. Mitarb. (1, 2) von periodischen Veranderungen der elektrischen Aktivitat des Cortex, die zeitlich den Atembewegungen entsprachen, berichtet. Jedoch konnten sic die Beziehungen zwischen elektrischer Aktivitat des Zentralnervensystems and der Atmung nicht klaren. Wir haben kiirzlich daruber berichtet (3), dass die Steigerung der elektrischen Aktivitat der Grosshirnrinde (Neocortex) bei Hypoventilation wahrscheinlich auf einer Aktivierung des Atemzentrums beruht, doch konnte die Beziehung zwischen beiden Vorgangen nur zum Teil geklart werden. Es wird nun von Versuchen berichtet, die uns der Beantwortung jener Frage naher bringen sollten.