EPIDEMIOLOGY OF CHLAMYDIA-INDUCED REPRODUCTIVE DISEASE IN MALE KOALAS (PHASCOLARCTOS CINEREUS) FROM SOUTHEAST QUEENSLAND, AUSTRALIA AS ASSESSED FROM PENILE URETHRAL SWABS AND SEMEN

Declining population sizes of koalas (Phascolarctos cinereus) in SE Queensland (QLD), Australia can partially be attributed to chlamydiosis, with the majority of epidemiological studies focusing on the prevalence of infection and associated pathology in female koalas, with lesser attention given to males. We aimed to explore the epidemiology of Chlamydia pecorum infection in the male urogenital tract from wild (hospitalized and free-ranging) koalas in SE QLD. Although 67% of male koalas were infected with C. pecorum in their urogenital tract and 55% were shedding the organism in their semen, only a third of the males sampled presented with overt signs of urogenital disease. Infection with C. pecorum was lower in populations from rural locations, compared with periurban locations, with a corresponding low association between urogenital infection and clinical disease. The presence of C. pecorum in penile urethral swabs was a good predictor of the presence of C. pecorum in semen, with a significant correlation (P=0.006) in 58% of males. In contrast, the C. pecorum load in penile urethral swabs was not a good predictor of the C. pecorum load in semen, with no significant correlation. In addition, 57% of male koalas had large numbers of bacterial copy numbers in the penile urethra (upper quartile) and 40% shedding into semen with no overt signs of disease. Investigation of the association of C. pecorum infection, body condition score, and age revealed that the highest incidence of urogenital infection occurred in males with the lowest body score (1 out of 10). Furthermore, 63% of sexually mature male koalas (>2 yr old) had urethral infections and 50% had C. pecorum in their semen. Our study suggested that the role of chlamydia in male koala infertility has been previously underestimated.

Pyridazino[3,4-b][1,5]Benzoxazepin-5(6H)-ones: Synthesis and Biological Evaluation

Starting from 3,6-dichloro-4-pyridazinecarboxylic acid chloride a series of novel pyridazino[3,4- b][1,5]benzoxazepin-5(6 H)-ones as 1,2-diazine isosters of nonnucleoside reverse transcriptase inhibitors was prepared via N-(2-hydroxyphenyl)-3,6-dichloro-4-pyridazinecarboxamides. The inhibition of HIV-1 reverse transcriptase was evaluated.

The Role of Bioacoustic Signals in Koala Sexual Selection: Insights from Seasonal Patterns of Associations Revealed with GPS-Proximity Units

Despite being a charismatic and well-known species, the social system of the koala (Phascolarctos cinereus--the only extant member of the family Phascolarctidae) is poorly known and much of the koala's sociality and mating behaviors remain un-quantified. We evaluated these using proximity logging-GPS enabled tracking collars on wild koalas and discuss their implications for the mating system of this species. The frequency and duration of male-female encounters increased during the breeding season, with male-male encounters quite uncommon, suggesting little direct mating competition. By comparison, female-female interactions were very common across both seasons. Body mass of males was not correlated with their interactions with females during the breeding season, although male size is associated with a variety of acoustic parameters indicating individuality. We hypothesise that vocal advertising reduces the likelihood of male-male encounters in the breeding season while increasing the rate of male-female encounters. We suggest that male mating-season bellows function to reduce physical confrontations with other males allowing them to space themselves apart, while, at the same time, attracting females. We conclude that indirect male-male competition, female mate choice, and possibly female competition, mediate sexual selection in koalas.

Feasibility of automated speech sample collection with stuttering children using interactive voice response (IVR) technology

PURPOSE

To investigate the feasibility of adopting automated interactive voice response (IVR) technology for remotely capturing standardized speech samples from stuttering children.

METHOD

Participants were 10 6-year-old stuttering children. Their parents called a toll-free number from their homes and were prompted to elicit speech from their children using a standard protocol involving conversation, picture description and games. The automated IVR system was implemented using an off-the-shelf telephony software program and delivered by a standard desktop computer. The software infrastructure utilizes voice over internet protocol. Speech samples were automatically recorded during the calls. Video recordings were simultaneously acquired in the home at the time of the call to evaluate the fidelity of the telephone collected samples. Key outcome measures included syllables spoken, percentage of syllables stuttered and an overall rating of stuttering severity using a 10-point scale.

RESULT

Data revealed a high level of relative reliability in terms of intra-class correlation between the video and telephone acquired samples on all outcome measures during the conversation task. Findings were less consistent for speech samples during picture description and games.

CONCLUSION

Results suggest that IVR technology can be used successfully to automate remote capture of child speech samples.

Review article: percutaneous endoscopic gastrostomy in infants and children

BACKGROUND

Percutaneous endoscopic gastrostomy (PEG) placement is widely accepted in children needing long-term gastrostomy feeding and clinical experience has been accumulated using PEG in children for nearly three decades.

AIM

To discuss the current knowledge about clinical application of percutaneous endoscopic gastrostomy in children as well as associated complications and special aspects.

METHODS

We reviewed literature on PEG, primarily in children, with a focus on complications, gastro-oesophageal reflux, potential benefits and parental perceptions. In addition to reviewing scientific literature, we considered clinical experience and judgment in developing recommendations for special aspects concerning PEG in children.

RESULTS

Since its introduction in 1980, the use of PEG in paediatric patients has become widely accepted. With expanded experience, the number of medical conditions for which PEG is indicated, as well as the use of new techniques has increased. Published reports have helped improve expertise in dealing with associated complications; however, several key issues remain unresolved such as the implications of gastro-oesophageal reflux associated with PEG placement.

CONCLUSIONS

Percutaneous endoscopic gastrostomy insertion for enteral nutrition in children and adolescents is an efficient and safe technique, even in small children, and is associated with a tolerable complication rate.

HPRT mutations in V79 Chinese hamster cells induced by accelerated Ni, Au and Pb ions

Mutation induction by accelerated heavy ions to 6-TG resistance (HPRT system) in V79 Chinese hamster cells was investigated with Ni (6-630 Me V/u), Au (2.2, 8.7 Me V/u) and Pb ions (11.6-980 Me V/u) corresponding to a LET range between 180 and 12895 ke V/microns. Most experiments could only be performed once due to technical limitations using accelerator beam times. Survival curves were exponential, mutation induction curves linear with fluence. From their slopes inactivation- and mutation-induction cross-sections were derived. If they are plotted versus LET, single, ion-specific curves are obtained. It is shown that other parameters like ion energy and effective charge play an important role. In the case of Au and Pb ions the cross-sections follow a common line, since these ions have nearly the same atomic weight, so that they should have similar spatial ionization patterns in matter at the same energies. Calculated RBEs were higher for mutation induction than for killing for all LETs.

Inverse dose-rate effect for the induction of 6-thioguanine-resistant mutants in Chinese hamster V79-S cells by 60Co gamma rays

Chinese hamster V79-S cells capable of growing in suspension culture were exposed to 60Co gamma rays at a high dose rate (84 Gy/h), low dose rates (200, 50, and 39 mGy/h), and a spectrum of very low dose rates (between 29 and 4.5 mGy/h). Following time for appropriate expression the cultures were assayed for the induction of 6-thioguanine-resistant mutants. For a given dose, a decrease in mutation induction occurred as the dose rate was reduced from high dose rates to low dose rates. However, further reduction in dose rate resulted in a reverse dose-rate effect, and an increase in the frequency of mutants was observed. The contribution of background mutation frequency to this reverse dose-rate effect was studied, both by examining fluctuations of mutation frequency in nonirradiated culture and by its impact upon the dose-rate-independent nature of the reversed effect, and it was found to be negligible. The physiological state of the suspension culture under periods of protracted exposure to very low dose rates was also investigated. The effect of doubling time, plating efficiency, cell cycle distribution, and sensitivity on survival and mutation were examined. In no case was a change apparent during the very low-dose-rate exposures. The results are discussed in terms of the possible expression of cryptic radiation damage after prolonged culture times and/or the involvement of an error-free repair system which requires a certain amount of radiation damage to become active.

[Behaviour of the peripheric leucocyte count and leucocyte resistance in rat after acute whole-body irradiation with 60Co-gamma-rays (author's transl)]

Wistar-rats were exposed to whole-body 60Co gamma irradiation and underwent continuous blood analysis through 70 days. By means of these experiments information as to the reliability of "values of the leucocyte resistance against ultrasound (LRW)" should be obtained in order to diagnose radiation injury. For all the dose ranges studied (from 10 R to 500 R) it was possible to ascertain a qualitatively radiation-specific LRW-curve being independent of the behaviour of peripheric leucocyte counts.