Gap creation alters the mode of conspecific distance-dependent seedling establishment via changes in the relative influence of pathogens and mycorrhizae.

In forest communities, conspecific density/distance dependence (CDD) is an important factor regulating diversity. It remains unknown how and the extent to which gap creation alters the mode and strength of CDD via changes in the relative importance of pathogens and mycorrhizae. Seeds of two hardwoods (i.e., Acer mono associated with arbuscular mycorrhizae [AM] and Quercus serrata associated with ectomycorrhizae [EM]) were sown reciprocally at four distances from the boundary between Acer- and Quercus-dominated forests towards forest interior in each of forest understories (FUs) and gaps. The causes of seed and seedling mortality, seedling growth and colonization of mycorrhizal fungi were investigated. In Acer, seed and seedling mortality were highest in Acer forests and gradually decreased towards the interior of Quercus forests in FU, mainly due to severe attack of soil pathogens, invertebrates, and leaf diseases. The reverse was true in gaps, due to reduction of damping-off damage caused by distance-dependent colonization of AM. In Quercus, most seeds and seedlings were eaten by vertebrates in FUs. The seedling mortality caused by leaf diseases was not high, even beneath conspecific forests with higher colonization of EM in gaps, suggesting a positive EM influence. In both species, seedling mass was greatest in conspecific forests and gradually decreased towards the interior of heterospecific forests in gaps, due to higher colonization of mycorrhizae near conspecifics. In conclusion, light conditions strongly altered the mode of CDD via changes in relative influence of pathogens and mycorrhizae, suggesting that gap creation may regulate species diversity via changes in the mode of CDD.

Role of mycorrhizal associations in tree spatial distribution patterns based on size class in an old-growth forest.

An important factor controlling tree species diversity is conspecific density dependence (CDD). Adult trees associated with arbuscular mycorrhiza (AM) and ectomycorrhiza (ECM) can exhibit negative and positive CDD effects on conspecific recruitment, respectively. However, the extent to which these mycorrhizal associations affect spatial distributions of individual trees and their relative abundances within forests through CDD remains uncertain. We analysed changes in spatial correlations between adults and conspecific juveniles at different growth stages of five hardwood species in a 6-ha plot of an old-growth forest using a point pattern analysis. The clump sizes of large individuals were also evaluated using the Iδ index (a measure of individual dispersion) in 24 species. In two AM-associated species, juveniles were distributed at greater distances with increasing size or were always distributed at a distance from adults, resulting in small clumps of adults. In contrast, juveniles of two ECM-associated species were distributed close to adults during early or late growth stage, resulting in large clumps of adults. Juveniles of an ECM-associated species disappeared with increasing size, probably due to shade intolerance. In 24 tree species with large numbers of individuals within a plot, the relative basal area was related to both mycorrhizal type and maximum diameter, suggesting that the relative abundance of a species is largely related to its mycorrhizal associations and maximum plant size. This study strongly demonstrated that mycorrhizal associations play an important role in determining the spatial distribution patterns and community structure of tree species through CDD.

Dynamics of Neotyphodium uncinatum and N-formylloline in Italian ryegrass, and their relation to insect resistance in the field.

AIMS: A fungal endophyte, Neotyphodium uncinatum, accumulates N-formylloline, which is toxic to Hemipteran insects, in Italian ryegrass. This study aimed to clarify the dynamics of N. uncinatum and N-formylloline in Italian ryegrass, and their relationship to insect resistance. METHODS AND RESULTS: Changes in the density and localization of N. uncinatum and N-formylloline in N. uncinatum-infected Italian ryegrass were examined by real-time PCR and gas chromatography, respectively. Neotyphodium uncinatum multiplied on pseudostems at the flowering stage, and then increased on inflorescences at the ripening stage. On the other hand, N-formylloline accumulated heavily in inflorescences and leaf blades, but lightly in pseudostems at the ripening stage. In field experiments, N. uncinatum-infected Italian ryegrass suppressed the occurrence of Stenotus rubrovittatus, which fed on the inflorescences, but was not effective to Laodelphax striatellus, which do not necessarily prefer a particular plant tissue. CONCLUSION: Localization of N. uncinatum and N-formylloline were discordant in Italian ryegrass. The N. uncinatum-infected Italian ryegrass was effective to only insects that prefer to feed on particular plant tissues containing N-formylloline. SIGNIFICANCE AND IMPACT OF STUDY: Our data implies that the relationship between insect habits and the dynamics of alkaloids in plants is important for the effective use of endophyte-infected crops.

Upgrading rural Japanese nurses' respiratory rehabilitation skills through videoconferencing.

We examined the effect of distance learning on nurses' clinical skills in a rural Japanese hospital. The subject matter was respiratory rehabilitation. After one face-to-face session, who 30 min sessions were delivered by videoconferencing to staff nurses working in a 100-bed rural hospital 250 miles (400 km) from Sapporo Medical University. A self-rating questionnaire was distributed before and after the sessions. Responses were collected from 15 out of 32 nurses participating in the face-to-face session (47%). Before the first videoconferencing session, 'always use' and 'sometime use' the new skills were rated by 67% of nurses, but after the second videoconferencing session 'always use' and 'sometimes use' were rated by 73% and 'never use' at 0%. This implies that there was increased use of new skills after the second session, although the difference was not significant. The nurses' opinions about the effectiveness for patients increased from 8% to 27% after the second session, which was significant. The pilot project indicated the usefulness of distance learning for upgrading nurses' clinical practice in one rural Japanese hospital and suggested ways in which videoconferencing can be used in future.

[Exposure to blood during midwifery operations--a questionnaire study].

A self-administered questionnaire was mailed to all midwives working in Nara Prefecture to investigate blood exposure events at delivery and to consider protective measures for the exposure. Out of the 203 midwives 193 responded to the questionnaire. The median number of deliveries in which the midwives had assisted within the past one year was 35 after excluding those who had not assisted in deliveries at all. The incidence of needle-stick injuries was estimated to be 86.2 per 100 persons within the past one year. The occurrence in the subgroup who had worked as midwife for less than 5 years was 2-3 times higher than that in those who worked for more than 5 years. Over 90% of the midwives had experiences of direct blood contact events to the skin while assisting in their 10 most recent deliveries. Blood contact events occurred in the finger-hand-arm area in 85% of the midwives, on the legs in 62%, in the face in 20% and in the eyes in 1%. Around 20% of the midwives had unintentionally sucked amniotic fluid when using a tracheal catheter on a newborn. The most common occasion where direct blood contact events occurred was while bathing an infant for removing blood and amniotic fluid. The midwives wore a disposal gown more often when assisting in labors of parturient women infected with blood-born infectious diseases than without the diseases, and similarly for wearing gloves when measuring blood loss and for usage of a mechanical device for sucking amniotic fluid in the tracheae of an infant. Based on the results obtained in this questionnaire study and our previous study about blood contact events observed in a delivery room, protective measures for midwives against exposure to blood at delivery are required and some ideas are presented.

[Exposure to blood during midwifery procedures--blood contact events to midwives occurred in a delivery room].

Midwives are often exposed to blood during delivery procedures. A study aimed at clarifying actual status of blood contact during midwifery procedures was performed. Observations in a delivery room were conducted to record blood contact events experienced by midwives from the time of episiotomy until 2 hour after expulsion of the placenta. All gloves used by midwives were collected and tested for holes. Blood contact was defined as any contact with blood of a parturition woman as recognized visually by an observer. During a one-month study period data was obtained from a total of 19 midwives (12 midwives and 7 student midwives) who assisted in 8 deliveries. All of the midwives wore gowns with long sleeves, gloves and caps but did not use eye protection or masks. None of the parturient women had Hepatitis B, Hepatitis C or acquired immunodeficiency syndrome. Deliveries caused widespread blood exposure to the midwives throughout the complete course. Protection from most of this exposure was provided by the gowns and gloves. However, direct blood contacts occurred to the fingers, hands or forearms in several midwives. These events were caused by partly because the midwives unintentionally performed procedures without gloves and partly because blood penetrated the gown and soaked to the skin. Direct blood contacts to the foot in two midwives and to the mouth in one also occurred. The overall perforation rate for gloves examined was 4 out of 154 (2.6%). Two gloves were broken during washing sharp instruments contaminated with blood, one was torn when wearing, and the remaining one appeared to have had a hole prior to use.(ABSTRACT TRUNCATED AT 250 WORDS)

[General pharmacology of T-1982, a new cephamycin antibiotic].

General pharmacological studies on T-1982 produced the following results. On central nervous system, subcutaneous injection of T-1982 at dose of 2,000 mg/kg hastened the onset of pentetrazole-induced tonic extensor in mice. T-1982 had no effect on spontaneous motor activity, pentobarbital hypnosis, body temperature or EEG in mice or rabbits, and also did not show motor incoordinate, anticonvulsive or analgesic activity in mice at intravenous doses of 250--1,000 mg/kg or subcutaneous doses of 500--2,000 mg/kg. On motor and sensory nervous systems, no effect of T-1982 was noted on spinal reflex, neuromuscular junction, conduction anesthesia or surface anesthesia in rats or rabbits. On respiratory, cardiovascular and autonomic nervous systems, T-1982 caused transient increase of respiratory rate, slight hypotension and transient increase of femoral blood flow in dogs at intravenous doses of 250--1,000 mg/kg. However, it caused a slight hypertensive tendency in rabbits. Heart rate and ECG in dogs or rabbits, blood pressure response to epinephrine, isoproterenol, acetylcholine or histamine in dogs, nictitating membrane in cats and pupil size in mice were not affected after intravenous injection of T-1982. No effect was found on isolated guinea pig atrium or rabbit descending aorta following T-1982 application. On renal function in rats, T-1982 caused an increase of PSP excretion but had no effect on urine volume or electrolytes excretion at intravenous doses of 250--1,000 mg/kg. T-1982 prolonged bleeding time in mice at intravenous doses of 500--1,000 mg/kg, but did not show hemolytic property and inhibitory activity on blood coagulation or platelet aggregation in vitro experiments. Spontaneous movement and tone of isolated stomach, ileum, colon, uterus, vas deferens or trachea and acetylcholine-, histamine-, nicotine- or barium chloride-induced contraction of ileum were not affected following T-1982 application. Intestinal propulsion of barium meal in mice, gastric secretion and carrageenin-induced edema in rats were not affected after intravenous injection of T-1982. T-1982 increased bile secretion in rats dose-dependently at intravenous doses of 31.3--125 mg/kg. The local irritative activity of T-1982 in rats was slightly milder than cefoxitin and moderately milder than cefmetazole after intradermal injection. In conclusion, these results suggest that T-1982 would not cause any adverse effects at its estimated clinical doses of 10--20 mg/kg (500--1,000 mg/man).

Influence of angiotensins (I, II & III) on prostaglandin production by minced rat renal medulla.

Minced rat renal medulla was incubated for 30 min at 37 degrees C in the presence of angiotensin I, II or III (100 ng/ml) to determine the existence of a direct stimulating effect on prostaglandin (PG) production. PGE2, PGF2 alpha, 6-keto PGF1 alpha and Thromboxane B2 (TXB2) were determined by radioimmunoassay. For analysis of data variance, the results were separated according to whether the net output of PGE2 was above or below 1.5 ng PGE2 equivalent/mg tissue/30 min. Under low-output conditions, angiotensin I, II or III stimulated PGE2 production significantly (p less than 0.02) and tended to augment PGF2 alpha production, while under high-output conditions no effect on PGE2 or PGF2 alpha production was observed. Under either output condition, angiotensin I, II or III had no effect on 6-keto PGF1 alpha and TXB2.