Reproductive interference in live-bearing fish: the male guppy is a potential biological agent for eradicating invasive mosquitofish.

The eradication of invasive exotic species is desirable but often infeasible. Here, we show that male guppies are a potential biological agent for eradicating invasive mosquitofish through the mechanism of reproductive interference, which is defined as any sexual behavior erratically directed at a different species that damages female and/or male fitness. Together with decades of data on species distribution, our field surveys suggest that mosquitofish initially became established on Okinawa Island before being replaced by the more recently introduced guppies. More importantly, our laboratory experiments suggest that reproductive interference was one of the mechanisms underlying this species exclusion, and that in this case, the negative effects were asymmetric, i.e., they only impacted mosquitofish. Reproductive interference may offer a safer and more convenient method of biological control than the traditional sterile male release method because radiation is not necessary.

Inheritance of song and stridulatory peg number divergence between Chorthippus brunneus and C. jacobsi, two naturally hybridizing grasshopper species (Orthoptera: Acrididae).

Knowledge of the genetic basis of divergence in mating signal characters that contribute to reproductive isolation is critical to understanding speciation. Here, we describe a semi-automated system for characterizing grasshopper acoustic signals. We used this system to study the genetic basis of divergence in three male calling song components [echeme (EL), syllable (SL) and phrase (PL) lengths] between Chorthippus brunneus and C. jacobsi, two species of grasshoppers that hybridize in northern Spain. We also studied the number of pegs in the stridulatory file. For all characters, additive effects accounted for most of the genetic differentiation between species. However, the three song components also showed small but significant epistatic effects. No sex linkage was detected. Wright-Castle-Lande estimates of the minimum numbers of genetic factors underlying song and peg number divergence were low: peg number (n(e)=5.87+/-5.84), SL (n(e)=2.37+/-4.79) and PL (n(e)=0.87+/-0.86). On the other hand, EL appeared to be controlled by many genes. These results suggest that divergence in SL and PL might be driven by sexual selection whereas EL might not be under selection. This is consistent with experimental results on female song preference in related species. However, the fact that few factors appear to underlie the differences in peg number is surprising. Peg number is not closely related to song characteristics. It often varies between closely related grasshopper species and it has been assumed to be a neutral character. The biometrical approaches used here tend to underestimate the number of factors influencing a trait but provide valuable background for subsequent quantitative trait loci analyses.

B chromosomes, translocation between B and autosomes, and C-heterochromatin polymorphism of the grasshopper Podisma sapporensis Shir. (Orthoptera, Acrididae) in Hokkaido, northern Japan.

Seven categories of B chromosomes found in the brachypterus grasshopper Podisma sapporensis from Hokkaido populations differ in structure, size, and C-band content. The interchange between B and one autosome from M3 and sporadically M7 was observed in most of the populations examined. Such an interaction between standard and non-standard chromosomal set provides an insight into the integration of supernumerary chromosome. In addition, C-heterochromatin polymorphism was also identified in male karyotypes in some populations. These facts indicate P. sapporensis is a highly polymorphic species from the cytogenetic point of view.

Comparative effect of theophylline and aminophylline on theophylline blood concentrations and peripheral blood eosinophils in patients with asthma.

The comparative effects of a new theophylline preparation (Theodrip) and aminophylline on blood concentrations of theophylline were examined in 74 patients with asthma. Subjects were intravenously administered 200 mg of Theodrip or 250 mg of aminophylline for 1 h. The mean increases in blood theophylline concentration after Theodrip or aminophylline administration were 8.80 +/- 1.80 mg/l and 8.81 +/- 2.15 mg/l, respectively. In addition, these patients were divided into four groups based on baseline theophylline concentrations before infusion of Theodrip or aminophylline: i) naïve patients (not administered theophylline); ii) those with a baseline theophylline concentration of 0-5 mg/l; iii) those with a baseline theophylline concentration of 5-10 mg/l; iv) those with a baseline theophylline concentration of 10-15 mg/l. Mean increases in blood theophylline concentration after administration of Theodrip in each group were similar to those after aminophylline administration. We found no significant differences between Theodrip and aminophylline. However, when the comparative effects of Theodrip and aminophylline on peripheral blood eosinophil counts were examined, Theodrip, but not aminophylline, reduced blood eosinophil counts. With acute exacerbations of bronchial asthma, it is expected that Theodrip, but not aminophylline, may have an antiinflammatory effect. In conclusion, it is suggested that Theodrip is a more useful drug than aminophylline in patients with acute exacerbations of bronchial asthma.

Chromosome polymorphism and C-banding variation of the brachypterous grasshopper Podisma sapporensis Shir. (Orthoptera, Acrididae) in Hokkaido, northern Japan.

The grasshopper Podisma sapporensis consists of two main chromosome races in Hokkaido. The western group of populations of P. sapporensis, belonging to the XO race, has a diploid number of chromosomes 2n = 23 in the male and 2n = 24 in the female (sex determination XO male/XX female). The eastern group of populations of this species, belonging to the XY race, differs from the western one as a result of Robertsonian translocation between the originally acrocentric X chromosome and M5 autosome in homozygous state, having resulted in the forming of chromosome sex determination neo-XY male/neo-XX female (2n = 22). These races are geographically isolated by the mountainous system consisting of the Mts Daisetsu and Hidaka range, occupying the central part of the island. The hybrid zones between the races have not so far been discovered. Various levels of polymorphism for the pericentric inversions and C-banding variation exist in different chromosomes throughout populations in both chromosome races. In some solitary populations (the population at the summit of Mt Yotei, populations in the vicinity of Naganuma, Oketo, and Tanno) pericentric inversions are fixed in some pairs of chromosomes, which enables marking of the discrete karyomorphes. In the Mt Daisengen population all chromosomes are two-armed as a result of fixing the pericentric inversions. These facts contradict karyotypical conservatism of the tribe Podismini. The level of diversity of P. sapporensis karyotypes could provide a new perspective on the evolutionary process of different karyotype in Orthoptera. The considerable occurrence of polymorphism in chromosomes suggests that karyotypic diversification is undergoing in P. sapporensis. The authors also proposed that P. sapporensis would be divided into four chromosome subraces in the XO chromosome race and two chromosome subraces in the XY race, on the basis of karyotypic features. These races may have been established by fundamental climatic changes during the glacial epoch.

[Active pulmonary tuberculosis in patients with lung cancer].

To clarify the features of the coexistence of active pulmonary tuberculosis in patients with lung cancer, we analyzed clinical data on 25 cases with coexisting lung cancer and active pulmonary tuberculosis encountered at Tokyo National Chest Hospital during the period from 1991 to 1998. There were 23 men and 2 women, with a mean age of 70 years. The incidence of lung cancer among patients with active pulmonary tuberculosis at our hospital was 0.7 per cent, while the incidence of active pulmonary tuberculosis in untreated lung cancer patients at our hospital was 1.9 per cent. We classified the 25 cases into 2 groups as follows: (1) tuberculosis sequential to lung cancer (11 cases) and (2) tuberculosis concurrently detected with lung cancer (14 cases). All patients in the former group were transferred from other hospitals after diagnosing the coexistence of pulmonary tuberculosis during the management of lung cancer. Histological types of lung cancer were squamous cell carcinoma in 12, adenocarcinoma in 9, and small cell carcinoma in 4, and as to the disease stage, stages III to IV were predominant. Analysis on relationship of chest X-ray findings between lung cancer and pulmonary tuberculosis revealed that in general, the location of lung cancer and tuberculosis seemed to be independent. Tuberculosis in the sequential group was more extensive and severer than in the concurrent group. In the concurrent group, treatment for tuberculosis was successful except for one case, and coexisting tuberculosis did not seem to affect the course of lung cancer among this group. However, in the sequential group, 5 patients died within 3 months, 2 of them died of tuberculosis. We consider that in the management of lung cancer, physicians should consider the possibility of coexistent active pulmonary tuberculosis and should not make delay in the diagnosis of active pulmonary tuberculosis.

GABAergic inhibition of hiccup-like reflex induced by electrical stimulation in medulla of cats.

We hypothesize that the hiccup reflex is actively inhibited through GABA(B) receptor within central connections of the hiccup reflex arc. Because the hiccup-like reflex can be elicited by electrical stimulation to a limited area within the medullary reticular formation, the hiccup-evoking site (HES), electrical stimulation (50-100 microA, three train pulses at 20 Hz) was delivered to HES by means of a metal electrode containing 1.0 mM baclofen, in anesthetized spontaneously breathing cats. The evoked response was characterized by a brief powerful increase in diaphragmatic activity and a temporal suppression of the posterior cricoarytenoid muscle, laryngeal dilator, which corresponded to the fixed motor pattern of hiccup reflex. The hiccup-like response was rapidly suppressed after microinjection of baclofen (0.1-0.5 nmol) into HES, indicating that HES has GABA(B) receptors. In the other experiments, to histologically examine the inputs to the hiccup reflex arc, unconjugated cholera toxin subunit B (UCTB) was injected into HES. Following injections of UCTB, retrogradely labelled cells were found distributed in various areas of the lower brainstem. Among these areas, the nucleus raphe magnus (RM) is reported to have GABA-containing cells. It is thus hypothesized that RM is most likely to be the source of the GABAergic inhibitory inputs to the hiccup reflex arc.

Organization of the human carboxypeptidase E gene and molecular scanning for mutations in Japanese subjects with NIDDM or obesity.

Insulin is synthesized in the pancreatic beta cell as a larger precursor molecule proinsulin which is converted to insulin and C-peptide by the concerted action of prohormone convertase 2 (PC2), prohormone convertase 3 (PC3) and carboxypeptidase E (CPE). One of the features of non-insulin-dependent diabetes mellitus (NIDDM) is an elevation in the proinsulin level and/or proinsulin/insulin molar ratio suggesting that mutations in these three proinsulin processing enzymes might contribute to the development of NIDDM. The identification of a mutation in the CPE gene of the fat/fat mouse which leads to marked hyperproinsulinaemia and late-onset obesity and diabetes is consistent with a possible role for mutations in CPE in the development of diabetes and obesity in humans. In order to test this hypothesis, we have isolated and characterized the human CPE gene and screened it for mutations in a group of Japanese subjects with NIDDM and obesity. The human CPE gene consists of 9 exons spanning more than 60 kb. Primer extension analysis identified the transcriptional start site at -141 bp from the translational start site. Single strand conformational polymorphism analysis and nucleotide sequencing of the promoter and entire coding region of the CPE gene in 269 Japanese subjects with NIDDM, 28 nondiabetic obese subjects and 104 nonobese and nondiabetic controls revealed three nucleotide changes, a G-to-T substitution at nucleotide -53, a G-to-A substitution at nucleotide -144 (relative to start of transcription) in the promoter region and a silent G-to-A substitution in codon 219. None of the nucleotide substitutions were associated with NIDDM or obesity. Thus, genetic variation in the CPE gene does not appear to play a major role in the pathogenesis of NIDDM or obesity in Japanese subjects.

Characterization of the promoter of the mouse prohormone convertase PC2 gene.

Prohormone convertase 2 (PC2) is a member of a family of mammalian subtilisin-like endoproteases that are involved in the processing of prohormones, neuropeptides and many other precursor derived proteins. The expression of PC2 is restricted to neuroendocrine tissues such as pancreatic islets, the pituitary and the brain. To understand the regulation of the PC2 gene, we cloned and characterized the promoter region of the mouse PC2 gene. The transcriptional start site of the mouse PC2 gene is identical to that of the human. There is 79% identity in the sequences of the promoter regions between the mouse and human PC2 genes. The mouse PC2 gene, like the human, does not have a TATA-like motif in the region just upstream of the start of the transcription. Studies with promoter-reporter gene, chloramphenicol acetyltransferase (CAT), constructs showed that the region from -400 to -170 bp was necessary for high level expression of the mouse PC2 gene in the betaTC-3 insulinoma cells.

Nonadrenergic relaxation of the cat cervical trachea evoked by stimulation in the lateral hypothalamic area.

The purpose of this study was to evaluate hypothalamic contributions to control of tracheal tone. We found hypothalamic sites where electrical stimulation (60-90 microA: 1 ms pulse duration: 50 Hz: 5-10 s) and microinjection of L-glutamate (5-50 nmol) produced tracheal relaxation responses along with decreased blood pressure and heart rate in anesthetized, spontaneously breathing cats. Responsive sites were located in anterior (LHAa) and tuberal (LHAt) regions of the lateral hypothalamic area indicating that neuronal cells in those regions are responsible for development of tracheal relaxation. In a second experiment, we evaluated possible pathways mediating the tracheal relaxation response elicited by LHA stimulation. Tracheal relaxation was not attenuated by beta-adrenergic blockade (propranolol i.v., 0.2-0.5 mg/kg); the response is mediated by nonadrenergic mechanisms Muscarinic blockade (atropine i.v.) at doses of 0.05-0.1 mg/kg almost abolished tracheal tone during spontaneous breathing, and LHA stimulation evoked a small, insignificant reduction of tracheal tone. Cervical vagotomy completely abolished the trachea tone, and LHA stimulation no longer evoked the tracheal relaxation. These results indicate the existence of a nonadrenergic descending pathway within the vagal efferents, which is linked with behavioral control arising from LHA, and causes trachea relaxation.

Human prohormone convertase 3 gene: exon-intron organization and molecular scanning for mutations in Japanese subjects with NIDDM.

Proinsulin is converted to insulin by the concerted action of two sequence-specific subtilisin-like proteases termed prohormone convertase 2 (PC2) and prohormone convertase 3 (PC3). PC3 is a type I proinsulin-processing enzyme that initiates the sequential processing of proinsulin to insulin by cleaving the proinsulin molecule on the COOH-terminal side of the dibasic peptide, Arg31-Arg32, joining the B-chain and C-peptide. Thus, PC3 plays a key role in regulating insulin biosynthesis. Expressions of insulin and PC3, but not PC2, are coordinately regulated by glucose, consistent with the important role of PC3 in regulating proinsulin processing. NIDDM is associated with increased secretion of proinsulin and proinsulin-like molecules, suggesting that mutations in the PC3 gene may be involved in the development of this disorder. To examine this hypothesis, we have isolated and characterized the human PC3 gene and screened it for mutations in a group of Japanese subjects with NIDDM. The PC3 gene consists of 14 exons spanning more than 35 kb. The exon-intron organization of PC2 and PC3 genes are conserved, consistent with a common evolutionary origin for the prohormone convertase gene family. Single-strand conformational analysis and nucleotide sequencing of the entire coding region of the PC3 gene in 102 Japanese subjects with NIDDM revealed missense mutations in exons 2 (Arg/Gln53) and 14 (Gln/Glu638), neither of which was associated with NIDDM in this population. These data suggest that genetic variation in the PC3 gene is unlikely to be a major contributor to NIDDM susceptibility in Japanese.

[Primary varicella pneumonia with respiratory failure].

Varicella pneumonia is a rare but serious and occasionally fatal complication of infection with varicellazoster. A 40-year-old man was admitted to our hospital with fever, eruptions, dyspnea, and severe hypoxemia. A chest X-ray film showed diffuse nodular infiltrative shadows in both lung fields. Transbronchial lung biopsy was done, and examination of the specimen revealed an organizing exudative reaction in the alveolar spaces, as well as interstitial inflammation. Primary varicella pneumonia was diagnosed on the basis of family history, typical eruptions, high titer of antibody against varicellazoster virus, and pathological findings. The patient was treated with methylprednisolone, antibiotics, acyclovir, and immunoglobulin. The skin eruptions and disturbances of gas exchange and diffusion resolved in about one week, but the infiltrative shadows on chest X-ray films remained for more than eight weeks.

Voltage- and time-dependent K+ channel currents in the basolateral membrane of villus enterocytes isolated from guinea pig small intestine.

Patch-clamp studies were carried out in villus enterocytes isolated from the guinea pig proximal small intestine. In the whole-cell mode, outward K+ currents were found to be activated by depolarizing command pulses to -45 mV. The activation followed fourth order kinetics. The time constant of K+ current activation was voltage-dependent, decreasing from approximately 3 ms at -10 mV to 1 ms at +50 mV. The K+ current inactivated during maintained depolarizations by a voltage-independent, monoexponential process with a time constant of approximately 470 ms. If the interpulse interval was shorter than 30 s, cumulative inactivation was observed upon repeated stimulations. The steady state inactivation was voltage-dependent over the voltage range from -70 to -30 mV with a half inactivation voltage of -46 mV. The steady state activation was also voltage-dependent with a half-activation voltage of -22 mV. The K+ current profiles were not affected by chelation of cytosolic Ca2+. The K+ current induced by a depolarizing pulse was suppressed by extracellular application of TEA+, Ba2+, 4-aminopyridine or quinine with half-maximal inhibitory concentrations of 8.9 mM, 4.6 mM, 86 microM and 26 microM, respectively. The inactivation time course was accelerated by quinine but decelerated by TEA+, when applied to the extracellular (but not the intracellular) solution. Extracellular (but not intracellular) applications of verapamil and nifedipine also quickened the inactivation time course with 50% effective concentrations of 3 and 17 microM, respectively. Quinine, verapamil and nifedipine shifted the steady state inactivation curve towards more negative potentials. Outward single K+ channel events with a unitary conductance of approximately 8.4 pS were observed in excised inside-out patches of the basolateral membrane, when the patch was depolarized to -40 mV. The ensemble current rapidly activated and thereafter slowly inactivated with similar time constants to those of whole-cell K+ currents. It is concluded that the basolateral membrane of guinea pig villus enterocytes has a voltage-gated, time-dependent, Ca(2+)-insensitive, small-conductance K+ channel. Quinine, verapamil, and nifedipine accelerate the inactivation time course by affecting the inactivation gate from the external side of the cell membrane.

[Prevention of alcohol-induced gastric mucosal injury by prostaglandin E-1].

Effects of ethanol and prostaglandin on the glycoprotein synthesis in the gastric mucus cells have been evaluated. The rat gastric mucosal cell were subjected to a short-term tissue culture in the presence of ethanol and prostaglandin E2 (Ornoprostil), using [3H]-proline, [3H]-palmitic acid, [3H]-galactosamine. Low concentration of ethanol (0.05-0.01 M) stimulated the glycoprotein synthesis, but higher concentration of ethanol (0.5-1.5 M) caused a marked reduction in the glycoprotein synthesis. Addition of prostaglandin E2, especially addition of prostaglandin prior to ethanol treatment, has improved the glycoprotein synthesis and secretion in the presence of ethanol. It was suggested that addition of prostaglandin resulted in the stabilization of the synthesis and secretion of the mucus glycoprotein in the presence of ethanol.