Effectiveness of a complex regional advance care planning intervention to improve care consistency with care preferences: study protocol for a multi-center, cluster-randomized controlled trial focusing on nursing home residents (BEVOR trial)

Background

According to recent legislation, facilitated advance care planning (ACP) for nursing home (NH) residents is covered by German sickness funds. However, the effects of ACP on patient-relevant outcomes have not been studied in Germany yet. This study investigates whether implementing a complex regional ACP intervention improves care consistency with care preferences in NH residents.

Methods

This is a parallel-group cluster-randomized controlled trial (cRCT) with 48 NHs (≈ 3840 resident beds) between 09/2019 and 02/2023. The intervention group will receive a complex, regional ACP intervention aiming at sustainable systems redesign at all levels (individual, institutional, regional). The intervention comprises comprehensive training of ACP facilitators, implementation of reliable ACP processes, organizational development in the NH and other relevant institutions of the regional healthcare system, and education of health professionals caring for the residents. Control group NHs will deliver care as usual.

Primary outcome is the hospitalization rate during the 12-months observation period. Secondary outcomes include the rate of residents whose preferences were known and honored in potentially life-threatening events, hospital days, index treatments like resuscitation and artificial ventilation, advance directives, quality of life, psychological burden on bereaved families, and costs of care.

The NHs will provide anonymous, aggregated data of all their residents on the primary outcome and several secondary outcomes (data collection 1). For residents who have given informed consent, we will evaluate care consistency with care preferences and further secondary outcomes, based on chart reviews and short interviews with residents, surrogates, and carers (data collection 2). Process evaluation will aim to explain barriers and facilitators, economic evaluation the cost implications.

Discussion

This study has the potential for high-quality evidence on the effects of a complex regional ACP intervention on NH residents, their families and surrogates, NH staff, and health care utilization in Germany. It is the first cRCT investigating a comprehensive regional ACP intervention that aims at improving patient-relevant clinical outcomes, addressing and educating multiple institutions and health care providers, besides qualification of ACP facilitators. Thereby, it can generate evidence on the potential of ACP to effectively promote patient-centered care in the vulnerable population of frail and often chronically ill elderly.

Trial registration

ClinicalTrials.gov ID NCT04333303. Registered 30 March 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06576-3.

Macrophage-based delivery of interleukin-13 improves functional and histopathological outcomes following spinal cord injury

BACKGROUND

Spinal cord injury (SCI) elicits a robust neuroinflammatory reaction which, in turn, exacerbates the initial mechanical damage. Pivotal players orchestrating this response are macrophages (Mφs) and microglia. After SCI, the inflammatory environment is dominated by pro-inflammatory Mφs/microglia, which contribute to secondary cell death and prevent regeneration. Therefore, reprogramming Mφ/microglia towards a more anti-inflammatory and potentially neuroprotective phenotype has gained substantial therapeutic interest in recent years. Interleukin-13 (IL-13) is a potent inducer of such an anti-inflammatory phenotype. In this study, we used genetically modified Mφs as carriers to continuously secrete IL-13 (IL-13 Mφs) at the lesion site.

METHODS

Mφs were genetically modified to secrete IL-13 (IL-13 Mφs) and were phenotypically characterized using qPCR, western blot, and ELISA. To analyze the therapeutic potential, the IL-13 Mφs were intraspinally injected at the perilesional area after hemisection SCI in female mice. Functional recovery and histopathological improvements were evaluated using the Basso Mouse Scale score and immunohistochemistry. Neuroprotective effects of IL-13 were investigated using different cell viability assays in murine and human neuroblastoma cell lines, human neurospheroids, as well as murine organotypic brain slice cultures.

RESULTS

In contrast to Mφs prestimulated with recombinant IL-13, perilesional transplantation of IL-13 Mφs promoted functional recovery following SCI in mice. This improvement was accompanied by reduced lesion size and demyelinated area. The local anti-inflammatory shift induced by IL-13 Mφs resulted in reduced neuronal death and fewer contacts between dystrophic axons and Mφs/microglia, suggesting suppression of axonal dieback. Using IL-4Rα-deficient mice, we show that IL-13 signaling is required for these beneficial effects. Whereas direct neuroprotective effects of IL-13 on murine and human neuroblastoma cell lines or human neurospheroid cultures were absent, IL-13 rescued murine organotypic brain slices from cell death, probably by indirectly modulating the Mφ/microglia responses.

CONCLUSIONS

Collectively, our data suggest that the IL-13-induced anti-inflammatory Mφ/microglia phenotype can preserve neuronal tissue and ameliorate axonal dieback, thereby promoting recovery after SCI.

Macrophage phagocytosis after spinal cord injury: when friends become foes

After spinal cord injury (SCI), macrophages can exert either beneficial or detrimental effects depending on their phenotype. Aside from their critical role in inflammatory responses, macrophages are also specialized in the recognition, engulfment, and degradation of pathogens, apoptotic cells, and tissue debris. They promote remyelination and axonal regeneration by removing inhibitory myelin components and cellular debris. However, excessive intracellular presence of lipids and dysregulated intracellular lipid homeostasis result in the formation of foamy macrophages. These develop a pro-inflammatory phenotype that may contribute to further neurological decline. Additionally, myelin-activated macrophages play a crucial role in axonal dieback and retraction. Here, we review the opposing functional consequences of phagocytosis by macrophages in SCI, including remyelination and regeneration versus demyelination, degeneration, and axonal dieback. Furthermore, we discuss how targeting the phagocytic ability of macrophages may have therapeutic potential for the treatment of SCI.

ADAM17-deficiency on microglia but not on macrophages promotes phagocytosis and functional recovery after spinal cord injury

A disintegrin and metalloproteinase 17 (ADAM17) is the major sheddase involved in the cleavage of a plethora of cytokines, cytokine receptors and growth factors, thereby playing a substantial role in inflammatory and regenerative processes after central nervous system trauma. By making use of a hypomorphic ADAM17 knockin mouse model as well as pharmacological ADAM10/ADAM17 inhibitors, we showed that ADAM17-deficiency or inhibition significantly increases clearance of apoptotic cells, promotes axon growth and improves functional recovery after spinal cord injury (SCI) in mice. Microglia-specific ADAM17-knockout (ADAM17flox^+/+-Cx3Cr1 Cre^+/-) mice also showed improved functional recovery similar to hypomorphic ADAM17 mice. In contrast, endothelial-specific (ADAM17flox^+/+-Cdh5Pacs Cre^+/-) and macrophage-specific (ADAM17flox^+/+-LysM Cre^+/-) ADAM17-knockout mice or bone marrow chimera with transplanted ADAM17-deficient macrophages, displayed no functional improvement compared to wild type mice. These data indicate that ADAM17 expression on microglia cells (and not on macrophages or endothelial cells) plays a detrimental role in inflammation and functional recovery after SCI.

Liver X Receptor Alpha Is Important in Maintaining Blood-Brain Barrier Function

Dysfunction of the blood-brain barrier (BBB) contributes significantly to the pathogenesis of several neuroinflammatory diseases, including multiple sclerosis (MS). Potential players that regulate BBB function are the liver X receptors (LXRs), which are ligand activated transcription factors comprising two isoforms, LXRα, and LXRβ. However, the role of LXRα and LXRβ in regulating BBB (dys)function during neuroinflammation remains unclear, as well as their individual involvement. Therefore, the goal of the present study is to unravel whether LXR isoforms have different roles in regulating BBB function under neuroinflammatory conditions. We demonstrate that LXRα, and not LXRβ, is essential to maintain barrier integrity in vitro. Specific knockout of LXRα in brain endothelial cells resulted in a more permeable barrier with reduced expression of tight junctions. Additionally, the observed dysfunction was accompanied by increased endothelial inflammation, as detected by enhanced expression of vascular cell adhesion molecule (VCAM-1) and increased transendothelial migration of monocytes toward inflammatory stimuli. To unravel the importance of LXRα in BBB function in vivo, we made use of the experimental autoimmune encephalomyelitis (EAE) MS mouse model. Induction of EAE in a constitutive LXRα knockout mouse and in an endothelial specific LXRα knockout mouse resulted in a more severe disease score in these animals. This was accompanied by higher numbers of infiltrating leukocytes, increased endothelial VCAM-1 expression, and decreased expression of the tight junction molecule claudin-5. Together, this study reveals that LXRα is indispensable for maintaining BBB integrity and its immune quiescence. Targeting the LXRα isoform may help in the development of novel therapeutic strategies to prevent BBB dysfunction, and thereby neuroinflammatory disorders.

HDAC3 Inhibition Promotes Alternative Activation of Macrophages but Does Not Affect Functional Recovery after Spinal Cord Injury

After spinal cord injury (SCI), monocyte derived macrophages play a detrimental role. Histone deacetylases (HDACs) are central epigenetic regulators of macrophage-polarization. We hypothesized that HDAC3 inhibition suppresses the pro-inflammatory macrophage phenotype (M1), promotes the anti-inflammatory phenotype (M2) and improves functional recovery after SCI. Therefore, two inhibitors of HDAC3 were selected, namely scriptaid and RGFP966. The impact on macrophage polarization was studied by investigating the effect on gene and protein expression of selected M1 and M2 markers. We show that scriptaid differentially influences M1 and M2 markers. It increases CD86 and iNOS gene expression and decreases GPR18, CD38, FPR2 and Arg-1 gene expression as well as the production of IL-6 and NO. RGFP966 primarily increased the expression of the M2 markers Arg-1 and Ym1 and reduced the production of IL-6 (M1). RGFP966 and scriptaid reduced the formation of foamy macrophages. Finally, to investigate the impact of HDAC3 inhibition on functional recovery after SCI, we studied the effects of RGFP966 and scriptaid in an in vivo T-cut hemisection SCI model. Histological analyses were performed on spinal cord sections to determine lesion size and astrogliosis, demyelinated area and selected infiltrating immune cells. RGFP966 and scriptaid did not affect functional recovery or histopathological outcome after SCI. In conclusion, these results indicate that specific HDAC3 inhibition with RGFP966 promotes alternative activation of macrophages and reduces the formation of foamy macrophages, but does not lead to a better functional recovery after SCI.

Salmonella detection in poultry samples

Study: The efficiency of two commercial PCR methods based on real-time technology, the foodproof® Salmonella detection system and the BAX® PCR Assay Salmonella system was compared to standardized culture methods (EN ISO 6579:2002 – Annex D) for the detection of Salmonella spp. in poultry samples. Material and methods: Four sample matrices (feed, dust, boot swabs, feces) obtained directly from poultry flocks, as well as artificially spiked samples of the same matrices, were used. All samples were tested for Salmonella spp. using culture methods first as the gold standard. In addition samples spiked with Salmonella Enteridis were tested to evaluate the sensitivity of both PCR methods. Furthermore all methods were evaluated in an annual ring-trial of the National Salmonella Reference Laboratory of Germany. Results: Salmonella detection in the matrices feed, dust and boot swabs were comparable in both PCR systems whereas the results from feces differed markedly. The quality, especially the freshness, of the fecal samples had an influence on the sensitivity of the real-time PCR and the results of the culture methods. In fresh fecal samples an initial spiking level of 100 cfu/25 g Salmonella Enteritidis was detected. Two-days-dried fecal samples allowed the detection of 14 cfu/25 g. Both real-time PCR protocols appear to be suitable for the detection of Salmonella spp. in all four matrices. The foodproof® system detected eight samples more to be positive compared to the BAX® system, but had a potential false positive result in one case. In 7-days-dried samples none of the methods was able to detect Salmonella likely through letal cell damage. Clinical relevance: In general the advantage of PCR analyses over the culture method is the reduction of working time from 4–5 days to only 2 days. However, especially for the analysis of fecal samples official validation should be conducted according to the requirement of EN ISO 6579:2002 – Annex D.

[Role of the poultry red mite (Dermanyssus gallinae) in the transmission of avian influenza A virus]

OBJECTIVE

The aim of this study was to investigate the role of the poultry red mite (Dermanyssus [D.] gallinae) in the horizontal transmission of avian influenza A virus (AIV) to chickens. This mite is the most common ectoparasite in poultry worldwide, and may play a role in the spread of infectious agents including AIV. Currently, the control of mites is difficult due to frequently developed resistance to many acaricides, their nocturnality and their ability to survive hidden without feeding for months.

MATERIALS AND METHODS

D. gallinae were collected in a commercial layer farm and housed in self-made fibreboard boxes. SPF chickens were intravenously infected with AIV strain A/turkey/Ontario/7732/1966 (H5N9). The viraemia in chickens was monitored and at an appropriate time point about 1000 mites were allowed to suck on the AIV infected chickens. Re-isolation of the virus from blood-filled mites was tried daily for 14 days using chicken embryo fibroblast cultures and embryonated chicken eggs. Subsequently, the virus containing mites were placed into boxes that contained naïve SPF chickens to enable virus transmission from mites to chickens. Possible transmission to the chickens was examined using clinical signs, serology, gross lesions, histopathology and immunohistochemistry.

RESULTS

Chickens developed a dose-dependent viraemia one day after infection, therefore this day was chosen for the bloodmeal of the mites. AIV was detected in mites after bloodsucking on AIV-infected chickens over a 10-day period. Naïve SPF chickens were infected during bloodsucking of AIV carrying mites. AIV isolates in mites and in chickens were undistinguishable from the original AIV inoculum by RT-PCR.

CONCLUSIONS

D. gallinae ingested AIV during bloodmeals on AIV infected chickens and are able to transmit AIV to SPF chickens. Therefore, mites serve as mechanical vector of AIV and may play a major role in the circulation of AIV within a facility or area although the life span of infectious virus in the mite is limited.

CLINICAL RELEVANCE

The proven transmission requires more than ever a systematic control of this ectoparasite in order to maintain poultry health and productivity. The demonstrated vector function of this mite is of great significance for poultry flocks all over the world.

The role of expert evaluation for microsleep detection

Recently, it has been shown by overnight driving simulation studies that microsleep density is the only known sleepiness indicator which rapidly increases within a few seconds immediately before sleepiness related crashes. This indicator is based solely on EEG and EOG and subsequent adaptive pattern recognition. Accurate microsleep recognition is very important for the performance of this sleepiness indicator. The question is whether expensive evaluations of microsleep events by a) experts are necessary or b) non-experts provide sufficient evaluations. Based on 11,114 microsleep events in case a) and 12,787 in case b) recognition accuracies were investigated utilizing (i) artificial neural networks and (ii) support-vector machines. Cross validated classification accuracies ranged between 92.2 % for (i,b) and 99.3 % for (ii, a). It is concluded that expert evaluations are very important to provide independent information for detecting microsleep.

5% Lidocaine Medicated Plaster for the Treatment of Postherpetic Neuralgia: A Review of the Clinical Safety and Tolerability

Postherpetic neuralgia (PHN) is a common, very painful, and often long-lasting complication of herpes zoster which is frequently underdiagnosed and undertreated. It mainly affects the elderly, many of whom are already treated for comorbidities with a variety of systemic medications and are thus at high risk of drug-drug interactions. An efficacious and safe treatment with a low interaction potential is therefore of high importance. This review focuses on the safety and tolerability of the 5% lidocaine medicated plaster, a topical analgesic indicated for the treatment of PHN. The available literature (up to June 2014) was searched for publications containing safety data regarding the use of the 5% lidocaine medicated plaster in PHN treatment; unpublished clinical safety data were also included in this review. The 5% lidocaine medicated plaster demonstrated good short- and long-term tolerability with low systemic uptake (3 ± 2%) and minimal risk for systemic adverse drug reactions (ADRs). ADRs related to topical lidocaine treatment were mainly application site reactions of mild to moderate intensity. The treatment discontinuation rate was generally below 5% of patients. In one trial, the 5% lidocaine medicated plaster was better tolerated than systemic treatment with pregabalin. The 5% lidocaine medicated plaster provides a safe alternative to systemic medications for PHN treatment, including long-term pain treatment.

LIM-only protein FHL2 is a positive regulator of liver X receptors in smooth muscle cells involved in lipid homeostasis

The LIM-only protein FHL2 is expressed in smooth muscle cells (SMCs) and inhibits SMC-rich-lesion formation. To further elucidate the role of FHL2 in SMCs, we compared the transcriptomes of SMCs derived from wild-type (WT) and FHL2 knockout (KO) mice. This revealed that in addition to the previously recognized involvement of FHL2 in SMC proliferation, the cholesterol synthesis and liver X receptor (LXR) pathways are altered in the absence of FHL2. Using coimmunoprecipitation experiments, we found that FHL2 interacts with the two LXR isoforms, LXRα and LXRβ. Furthermore, FHL2 strongly enhances transcriptional activity of LXR element (LXRE)-containing reporter constructs. Chromatin immunoprecipitation (ChIP) experiments on the ABCG1 promoter revealed that FHL2 enhances the association of LXRβ with DNA. In line with these observations, we observed reduced basal transcriptional LXR activity in FHL2-KO SMCs compared to WT SMCs. This was also reflected in reduced expression of LXR target genes in intact aorta and aortic SMCs of FHL2-KO mice. Functionally, the absence of FHL2 resulted in attenuated cholesterol efflux to both ApoA-1 and high-density lipoprotein (HDL), in agreement with reduced LXR signaling. Collectively, our findings demonstrate that FHL2 is a transcriptional coactivator of LXRs and points toward FHL2 being an important determinant of cholesterol metabolism in SMCs.

ABCC6-mediated ATP secretion by the liver is the main source of the mineralization inhibitor inorganic pyrophosphate in the systemic circulation-brief report

OBJECTIVE

Mutations in ABCC6 underlie the ectopic mineralization disorder pseudoxanthoma elasticum (PXE) and some forms of generalized arterial calcification of infancy, both of which affect the cardiovascular system. Using cultured cells, we recently showed that ATP-binding cassette subfamily C member 6 (ABCC6) mediates the cellular release of ATP, which is extracellularly rapidly converted into AMP and the mineralization inhibitor inorganic pyrophosphate (PPi). The current study was performed to determine which tissues release ATP in an ABCC6-dependent manner in vivo, where released ATP is converted into AMP and PPi, and whether human PXE ptients have low plasma PPi concentrations.

APPROACH AND RESULTS

Using cultured primary hepatocytes and in vivo liver perfusion experiments, we found that ABCC6 mediates the direct, sinusoidal, release of ATP from the liver. Outside hepatocytes, but still within the liver vasculature, released ATP is converted into AMP and PPi. The absence of functional ABCC6 in patients with PXE leads to strongly reduced plasma PPi concentrations.

CONCLUSIONS

Hepatic ABCC6-mediated ATP release is the main source of circulating PPi, revealing an unanticipated role of the liver in systemic PPi homeostasis. Patients with PXE have a strongly reduced plasma PPi level, explaining their mineralization disorder. Our results indicate that systemic PPi is relatively stable and that PXE, generalized arterial calcification of infancy, and other ectopic mineralization disorders could be treated with PPi supplementation therapy.

[Investigation of the practical use of a vaccination device ("Pullet Vaccinator") for young layers]

OBJECTIVE

To evaluate the safety of layer vaccination of the vaccination device "Pullet Vaccinator", its publicised increased operational safety and the practicality of the device using serological monitoring of the vaccination success.

MATERIALS AND METHODS

In a first trial, two veterinarians experienced in the syringe method vaccinated hens using the syringe and the vaccination device, respectively. After 1 hour, the equipment was switched and both veterinarians continued to vaccinate for a further hour. The second trial proceeded as in the first trial, except with untrained persons. For each of the four vaccination groups (experienced/syringe; experienced/device; untrained/syringe; untrained/device), the number of vaccinated hens was counted and 20 hens were dissected from each group to compare the impact of both inoculation methods on the animals. To monitor vaccination success, blood was collected for serological screening. On the final blood collection day, further hens per group were dissected to evaluate possible long-term injuries.

RESULTS

The vaccination device offers greater occupational safety compared to the syringe method. Vaccination injuries to the hens' breast muscles were more pronounced with the syringe application. For experienced persons, the number of vaccinated animals per hour was approximately doubled using the syringe compared to the device. For the untrained, a comparable number of vaccinated animals was recorded for both methods. Serological monitoring did not show any significant differences in antibody response to the vaccination between both methods.

CONCLUSION AND CLINICAL RELEVANCE

In certain points, the device proved technically imperfect and should be revised for improved use in the field.

Untersuchungen zum Einsatz des Impfautomaten „Pullet Vaccinator“ in der Junghennenaufzucht

Gegenstand und Ziel: Überprüft werden sollten Sicherheit und Unbedenklichkeit der Vakzination von Hühnern mit dem Impfautomaten „Pullet Vaccinator“, die vom Hersteller propagierte höhere Arbeitssicherheit und die Praktikabilität des Systems mit anschließender serologischer Kontrolle des Impferfolgs. Material und Methoden: Im ersten Versuchsabschnitt impfte je ein mit dem Spritzenverfahren geübter Tierarzt parallel mit der halbautomatischen Spritze und mit dem Automaten. Nach 1 Stunde wurden die Impfgeräte getauscht und für eine weitere Stunde geimpft. Der zweite Versuchsteil verlief analog zum ersten, doch führten hier im Impfen ungeübte Personen die Vakzination durch. Die Anzahl der geimpften Hennen wurde gezählt und von jeder der vier Impfgruppen (geübt/Spritze; geübt/Automat; ungeübt/Spritze; ungeübt/Automat) wurden 20 Tiere seziert, um die Auswirkungen der beiden Methoden zu vergleichen. Weiterhin erfolgte eine serologische Untersuchung zur Prüfung des Impferfolgs. Für die Evaluierung möglicher Spätfolgen der Vakzination wurden am letzten Termin der Blutentnahme weitere Hennen seziert. Ergebnisse: Der Impfautomat bietet eine höhere Arbeitssicherheit als die halbautomatische Spritze. Nach Spritzenapplikation lagen ausgeprägtere Impfschäden in der Muskulatur der Hühner vor. Geübte Personen impften mit der Spritze pro Stunde etwa doppelt so viele Tiere wie mit dem Automaten. Wurden die Impfungen von ungeübten Personen vorgenommen, war die Zahl geimpfter Tiere bei beiden Verfahren annähernd gleich. Die serologische Untersuchung ergab keine signifikanten Unterschiede zwischen den zwei Methoden in Bezug auf den Impferfolg. Schlussfolgerung und klinische Relevanz: Technisch ist der Impfautomat in einzelnen Punkten noch nicht ausgereift und sollte überarbeitet werden, um im praktischen Einsatz bestehen zu können.

Salmonella detection in poultry samples. Comparison of two commercial real-time PCR systems with culture methods for the detection of Salmonella spp. in environmental and fecal samples of poultry

STUDY

The efficiency of two commercial PCR methods based on real-time technology, the foodproof® Salmonella detection system and the BAX® PCR Assay Salmonella system was compared to standardized culture methods (EN ISO 6579:2002 - Annex D) for the detection of Salmonella spp. in poultry samples.

MATERIAL AND METHODS

Four sample matrices (feed, dust, boot swabs, feces) obtained directly from poultry flocks, as well as artificially spiked samples of the same matrices, were used. All samples were tested for Salmonella spp. using culture methods first as the gold standard. In addition samples spiked with Salmonella Enteridis were tested to evaluate the sensitivity of both PCR methods. Furthermore all methods were evaluated in an annual ring-trial of the National Salmonella Reference Laboratory of Germany.

RESULTS

Salmonella detection in the matrices feed, dust and boot swabs were comparable in both PCR systems whereas the results from feces differed markedly. The quality, especially the freshness, of the fecal samples had an influence on the sensitivity of the real-time PCR and the results of the culture methods. In fresh fecal samples an initial spiking level of 100cfu/25g Salmonella Enteritidis was detected. Two-days-dried fecal samples allowed the detection of 14cfu/25g. Both real- time PCR protocols appear to be suitable for the detection of Salmonella spp. in all four matrices. The foodproof® system detected eight samples more to be positive compared to the BAX® system, but had a potential false positive result in one case. In 7-days-dried samples none of the methods was able to detect Salmonella likely through letal cell damage.

CLINICAL RELEVANCE

In general the advantage of PCR analyses over the culture method is the reduction of working time from 4-5 days to only 2 days. However, especially for the analysis of fecal samples official validation should be conducted according to the requirement of EN ISO6579:2002 - Annex D.

[Air conducted ocular VEMP: II. First clinical investigations]

BACKGROUND

Vestibular-evoked myogenic potentials (VEMP) are widely used to assess vestibular function. Air conducted (AC) cervical VEMP (cVEMP) reflect sacculus and inferior vestibular nerve function. Ocular VEMP (oVEMP) however has been hardly examined up to now. In recent studies it has been assumed that AC oVEMP probably reflects superior vestibular nerve function. The aim of this pilot study was to evaluate clinical application of the AC oVEMP.

MATERIAL AND METHODS

AC oVEMP were recorded in patients with peripheral vestibular disorders (n=21). In addition thermal irritation and head impulse test were performed and AC cVEMP were recorded. For intense AC-sound stimulation tone bursts (500 Hz) with 100 dB nHL were used.

RESULTS

In peripheral vestibular disorders AC oVEMP and AC cVEMP could be classified into: • type 1 (inferior vestibular neuritis) with loss of AC oVEMP but normal AC cVEMP, • type 2, probable type of superior vestibular neuritis, showing present AC cVEMP but loss of AC oVEMP, • type 3, probable complete vestibular neuritis, without AC oVEMP and AC cVEMP.

CONCLUSIONS

AC oVEMP may be used as an appropriate test for clinical investigation in patients with vestibular disorders. AC oVEMP is an additional, essential test for assessing otolith function beside AC cVEMP. Further vestibular test are necessary for precise clinical interpretation.

[Air conducted ocular VEMP: I. Determination of a method and application in normal patients]

BACKGROUND

Air conducted (AC) cervical vestibular evoked myogenic potentials (AC cVEMP) and air conducted ocular VEMP (AC oVEMP) may be used for measurement of otolith function. However AC oVEMP are few examined till now. The aim of this pilot study was to apply a method for use of AC oVEMP in clinical practice.

PATIENTS AND METHODS

AC oVEMP were recorded in healthy voluntary people (n=20) using intense AC-sound stimulation (500 Hz tone bursts, 100 dB nHL). Thermal irrigation and AC cVEMP were normal as including criteria. Values were evaluated statistically.

RESULTS

AC oVEMP were recorded in all healthy patients. Mean and standard deviation for the first negative peak was 11.35±1.00 ms and for the first negative peak 16.30±1.10 ms. The mean amplitudes were 7.70±4.50 μV. The stability of n10 and p15 component was the same.

CONCLUSIONS

AC oVEMP can be easy and fast obtained. N10 and p15 latencies may used as parameter for clinical interpretation. Amplitude fluctuations are relatively large. Results can be used in further clinical investigation of AC oVEMP.

Evaluation of PERCLOS based current fatigue monitoring technologies

In an overnight driving simulation study three commercially available devices of fatigue monitoring technologies (FMT) were applied to test their accuracy. 16 volunteers performed driving tasks during eight sessions (40 min each) separated by 15 minutes breaks. The main output variable of FMT devices, which is the percentage of eye closure (PERCLOS), the driving performance (standard deviation of lateral position in lane, SDL), the electroencephalogram (EEG) and electrooculogram (EOG) were recorded during driving. In addition, the subjective self-rated Karolinska sleepiness scale (KSS) was assessed every 2 min. As expected, Pearson product-moment correlation coefficient (PMCC) yielded significant linear dependence between KSS and PERCLOS as well as between SDL and PERCLOS. However, if PMCC was estimated within smaller data segments (3 min) as well as without averaging across subjects then strongly decreased correlation coefficients resulted. To further validate PERCLOS at higher temporal resolution its ability to discriminate between mild and strong fatigue was investigated and compared to the results of the same analysis for EEG/EOG. Spectral-domain features of both types of signals were classified using Support-Vector Machines (SVM). Results suggest that EEG/EOG indicate driver fatigue much better than PERCLOS. Therefore, current FMT devices perform acceptably if temporal resolution is low (> 20 min). But, even under laboratory conditions large errors have to be expected if fatigue is estimated on an individual level and with high temporal resolution.

[The use of artificial neural networks in evaluation of posturographic data]

BACKGROUND

Posturography methods have been applied in clinical neurootology to evaluate the equilibrium function of patients. Methods of statistical analysis play an important role for improving data processing and to support the interpretation of the results. In contrast to conventional statistics, artificial neural networks are model-free and non-parametric. The aim of the presented study was to investigate how accurately these methods are able to discriminate between healthy and equilibrium-disturbed subjects.

PATIENTS AND METHODS

51 healthy volunteers participated in this study. 2 static posturography measurements were recorded before and 40 min after alcohol intake (0.4‰-0.6‰). Recorded signals were processed by 4 different methods in order to estimate power spectral densities (0 Hz-25 Hz). 11 different methods of artificial neural networks were investigated. The ability of artificial neural networks for classification was evaluated in patients with an acute unilateral vestibular loss.

RESULTS

It turned out that estimating power spectral densities by means of autoregressive modelling and subsequent classification by Support-Vector Machine or by Learning Vector Quantization Networks are most accurate. Validation analysis yielded mean classification errors for the test set of 4.2 ± 2.2%.

CONCLUSIONS

Analysis of neurootological data by artificial neural networks proved to be a sensitive recognition method of even small changes of the postural system.

Monitoring of drowsiness and microsleep

An overview is presented of different studies on monitoring and detection of drowsiness and microsleep (MS) during driving simulation.

[BeO-OSL detectors for dose measurements in cell cultures]

AIM

The absorbed dose is an important parameter in experiments involving irradiation of cells in vitro with unsealed radionuclides. Typically, this is estimated with a model calculation, although the results thus obtained cannot be verified. Generally used real-time measurement methods are not applicable in this setting. A new detector material with in vitro suitability is the subject of this work.

METHODS

Optically-stimulated luminescence (OSL) dosimeters based on beryllium oxide (BeO) were used for dose measurement in cell cultures exposed to unsealed radionuclides. Their qualitative properties (e. g. energy-dependent count rate sensitivity, fading, contamination by radioactive liquids) were determined and compared to the results of a Monte Carlo simulation (using AMOS software). OSL dosimeters were tested in common cell culture setups with a known geometry.

RESULTS

Dose reproducibility of the OSL dosimeters was +/-1.5%. Fading at room temperature was 0.07% per day. Dose loss (optically-stimulated deletion) under ambient lighting conditions was 0.5% per minute. The Monte Carlo simulation for the relative sensitivity at different beta energies provided corresponding results to those obtained with the OSL dosimeters. Dose profile measurements using a 6 well plate and 14 ml PP tube showed that the geometry of the cell culture vessel has a marked influence on dose distribution with 188Re.

CONCLUSION

A new dosimeter system was calibrated with beta-emitters of different energy. It turned out as suitable for measuring dose in liquids. The dose profile measurements obtained are suitably precise to be used as a check against theoretical dose calculations.

[Osteoblast reaction on SLA and microgrooved implant surfaces]

The osseointegration process of dental implants depends on the tissue reaction at the tissue-implant interface. Osteoblasts are the main cells responsible for the regulation of osteoinduction. The manner and kinetics of the tissue reaction crucially depend on the interaction between osteoblasts and the morphology of the implant surface. The aim of this study was to investigate osteoblast behaviour on different implant surfaces (smooth, microgrooved, SLA) under standardized conditions. For this in vitro investigation we used primary bovine osteoblasts. Attachment kinetics, proliferation rate and synthesis of bone-associated proteins were used as parameters for cell reaction. The results demonstrate that both attachment and adhesion strength of the primary cell surface interaction was higher on the microgrooved surfaces than on SLA surfaces. The proliferation rate of cells and the synthesis of bone-specific proteins were higher on microgrooved surfaces in contrast to SLA surfaces. Ultrastructural analysis revealed phenotypic osteoblast-like cells on smooth and microgrooved surfaces, whereas cells on SLA surfaces showed a more fibroblastic appearance. This study demonstrates that the morphology of the implant surface determined the subsequent osteoblast reaction. An optimal cell reaction was found at surfaces which are smooth in the microenvironment of osteoblasts.

A quantitative analysis of anaesthetist-patient communication during the pre-operative visit

Previous communication research in general medical practice has shown that effective communication enhances patient compliance, satisfaction and medical outcome. It is expected that communication is equally important in anaesthesia, since patients often suffer from anxiety and lack of knowledge about anaesthetic procedures. However, little is known about the nature of communication during routine anaesthetic visits. The present study of 57 authentic anaesthetic visits provides the first results on the structure and content of communication in the pre-operative setting using the Roter Interaction Analysis System (RIAS). Patient-centred communication behaviours of anaesthetists and the extent of patient involvement were particularly investigated. From the 57 pre-operative visits, 18 267 utterances were coded. The mean (SD) [range] duration of the visit was 16.1 (7.8) [3.7-42.7] min. Anaesthetists provided 169 (68) and patients 153 (82) utterances per visit (53.5% vs. 46.5%). Physician and patient gender had no impact on the distribution of utterances and the duration of the visit. Conversation mainly focussed on biomedical issues with little psychosocial discussion (< 0.1% of all anaesthetist utterances). However, anaesthetists quite frequently used emotional comments toward patients (7%) and involved them in the conversation. The use of facilitators, open questions and emotional statements by the anaesthetist correlated with high patient involvement. The amount of patient participation in anaesthetic decisions was assessed with the Observing Patient Involvement Scale (OPTION). Compared with general practitioners, anaesthetists offered more opportunities to discuss treatment options (mean (SD) OPTION score 26.8 (16.8) vs. 16.8 (7.7)).

Modulation of the phosphatase activity of calcineurin by oxidants and antioxidants in vitro

Previous research has indicated that oxidants, antioxidants and the intracellular redox state regulate the activities of a variety of protein tyrosine kinases, protein tyrosine phosphatases, phospholipases and transcription factors. In order to explore the redox regulation of the serine/threonine phosphatase calcineurin, we have investigated the effects of a variety of oxidants and antioxidants on calcineurin phosphatase activity in vitro. The oxidants hydrogen peroxide, superoxide and glutathione disulfide inhibited the phosphatase activity of calcineurin in a dose-dependent manner. Incubation of purified calcineurin with the antioxidants ascorbate, ascorbate 2-phosphate, alpha-lipoic acid, N-acetyl-L-cysteine and glutathione increased phosphatase activity relative to untreated controls. In contrast, several other commonly used antioxidants, including butylated hydroxytoluene, butylated hydroxyanisole, TEMPOL (4-hydroxy-2,2,6, 6-tetramethylpiperidine-N-oxyl), Trolox (6-hydroxy-2,5,7, 8-tetramethyl-chroman-2-carboxylic acid) and dihydrolipoic acid decreased the activity of purified calcineurin, possibly through prooxidative mechanisms. Although the antioxidant pyrrolidine dithiocarbamate increased the activity of purified calcineurin, it significantly inhibited the activity of calcineurin present in crude fibroblast lysates. These results support and extend the hypothesis that redox factors modulate the phosphatase activity of calcineurin and suggest that further in vivo studies are warranted.

Advances in the management of major airway collapse: the use of airway stents

The management of major airway collapse in the pediatric age group has evolved and continues to evolve over time. Tracheobronchomalacia, either primary or secondary, is still the most frequent cause of major airway collapse. This article reviews tracheobronchomalacia and discusses several treatment options; from traditional aortopexy to the more recent introduction of tracheobronchial stenting. Various types of stents are discussed and the authors' preferences are included.

Fetal trisomy 10 mosaicism: ultrasound, cytogenetic and morphologic findings in early pregnancy

We report the ultrasound, cytogenetic and morphologic findings in a case of trisomy 10 mosaicism prenatally detected by chorionic villus sampling (CVS). CVS sampling was carried out at the 13th week of gestation because of ultrasound diagnosis of hydrops fetalis and hygroma colli. Trisomy 10 mosaicism was diagnosed in cells from the cytotrophoblast (short-term culture) and the chorionic villus core (long-term culture). Fetal mosaicism was confirmed after termination of pregnancy in umbilical cord cells, placenta and fetal skin fibroblasts.

Mitochondrial DNA synthesis studied autoradiographically in various cell types in vivo

It is generally accepted that mitochondria are able to proliferate even in postmitotic cells due to their natural turnover and also to satisfy increased cell energy requirements. However, no detailed studies are available, particularly with respect to specific cell types. Since [3H]-thymidine is incorporated not only into nuclear (n) DNA but also into the DNA of cytoplasmic mitochondria, an autoradiographic approach was developed at the light microscopy level in order to study basic questions of mitochondrial (mt) proliferation in organs of rodents in situ via the cytoplasmic incorporation of [3H]-thymidine injected into the animals 1 h before sacrifice. Experiments carried out on mice after X-irradiation showed that cytoplasmic labeling was not due to a process such as unscheduled nuclear DNA synthesis (nUDS). Furthermore, half-lives of mitochondria between 8-23 days were deduced specifically in relation to cell types. The phase of mtDNA synthesis was about 75 min. Finally, mt proliferation was measured in brain cells of mice as a function of age. While all neurons showed a decreasing extent of mtDNA synthesis during old age, nUDS decreased only in distinct cell types of the cortex and hippocampus. We conclude that the leading theories explaining the phenomenon of aging are closely related, i.e., aging is due to a decreasing capacity of nDNA repair, which leads to unrepaired nDNA damage, or to an accumulation of mitochondria with damaged mtDNA, which leads to a deficit of cellular energy production.

Phylloid pigmentary pattern with mosaic trisomy 13

In most patients with hypomelanosis of Ito, the hypopigmentation is characterized by narrow bands following the lines of Blaschko. We report a 13-year-old severely retarded girl with leaf-shaped patches of hypopigmentation on the back together with short stature, scoliosis, facial dysmorphism, and asymmetrical leg length. The cytogenetic examination of both lymphocytes and fibroblasts demonstrated a mosaicism of 46,XX/47,XX+13. This result was confirmed by in situ hybridization using a chromosome 13-specific library in interphase cells. The pigmentary disturbance of our patient was similar to the phylloid pattern (type 3) of the classification of pigmentary patterns postulated by Happle. This type has been described in four patients so far, along with additional anomalies and a chromosomal mosaisicm in two patients.

A possible tyrosine phosphorylation of phytochrome

Red/far-red light signal transduction by the phytochrome family of photoreceptors regulates plant growth and development. We investigated the possibility that tyrosine kinases and/or phosphatases are involved in phytochrome-mediated signal transduction using crude extracts of oat seedlings that are grown in the dark. We found that a 124 kDa protein was tyrosine-phosphorylated as determined by Western blotting with a phosphotyrosine-specific monoclonal antibody. The 124 kDa protein was recognized by the anti-phosphotyrosine antibody in anti-phytochrome A immunoprecipitates. The level of anti-phosphotyrosine antibody binding to the 124 kDa protein(s) in phytochrome immunoprecipitates that had been treated with red light prior to immunoprecipitation decreased relative to dark controls. These results suggest that either phytochrome from dark-grown seedlings is tyrosine phosphorylated or that it co-immunoprecipitates with a phosphotyrosine-containing protein of the same molecular weight. The implications of these results in the regulation of (a) the putative Ser/Thr kinase activity of the photoreceptor and (b) the binding of signaling molecules, such as phospholipase C to phytochrome, are discussed.

Light signal transduction mediated by phytochromes: preliminary studies and possible approaches

Phytochromes mediate a variety of developmental and growth processes involved in the photomorphogenesis of plants. In this article, we review the current understanding of the structure and function of the photoreceptor, discuss some very preliminary results, and offer speculations and even conjectures that may elicit future studies into the molecular mechanisms of the phytochrome-mediated light signal transduction in plants.

Factors affecting herd milk composition and milk plasmin at four levels of somatic cell counts

A longitudinal study was carried out on samples of bulk tank milk collected from 200 farms for 12 mo to evaluate SCC, plasmin and plasminogen activities, psychrotrophic bacteria count, and protein quality in milk and to examine the proteolytic effects of plasmin on milk proteins. Herds were selected randomly from client lists of two dairies to create four groups based on milk SCC of the month before the study; herds were reassigned monthly to one of four groups based on SCC for that month. Overall means were 3.73% fat, 3.13% protein by infrared analysis, 3.16% protein by Kjeldahl analysis, 2.42% casein percentage, 4.65% lactose, 5.43 cells/ml of log SCC, 1.13 U of plasmin, 45.6 U of plasminogen, and log 2.86 cfu/ml of psychrotrophic bacteria. The ANOVA showed a significant effect of month on all factors except SCC, which was fixed by the experimental design. Plasmin and plasminogen activities were high from December to May. Plasmin activities and psychrotroph counts were significantly higher for the high SCC group. Casein percentage and number were significantly higher for the low SCC group.

Isolation and purification of a small-molecular-weight GTP-binding protein from plants

As part of testing the hypothesis that signal transduction in higher plants is mediated by G-protein(s), a 24-kDa GTP-binding protein was isolated and purified to near homogeneity from 3.5-day-old dark grown oat (Avena) seedlings by hydroxyapatite, GTP-agarose, and Sephacryl S-200 chromatographies. The protein bound maximally 0.9 +/- 0.1 mol of [35S]guanosine 5'-(3-O-thio) triphosphate (GTP gamma S)/mol of protein with an apparent Kd of approximately 32 nM. Although binding of [35S]GTP gamma S was inhibited by both GTP and GDP, no inhibition of [35S]GTP gamma S binding was observed in the presence of ATP, UTP, CTP, ITP, or TTP. The 24-kDa protein hydrolyzed GTP with a rate of 0.06 mol Pi/mol protein/min. The results suggest that this GTP-binding protein is a unique plant GTP-binding protein that exhibits characteristics similar to those of animal ras-related GTP-binding proteins.

A plant nucleoside diphosphate kinase homologous to the human Nm23 gene product: purification and characterization

Nucleoside diphosphate kinases (NDPKs) catalyze the transfer of high-energy phosphates from nucleoside triphosphates to nucleoside diphosphates and may be involved in the regulation of growth, development, and signal transduction processes. We report here the purification and characterization of NDPK from detergent-solubilized extracts of dark-grown oat (Avena) tissue. The purification was achieved primarily through adsorption to GTP-agarose, followed by elution with ATP. SDS-polyacrylamide gel electrophoresis and gel filtration chromatography indicated that the purified protein is composed of six 18 kDa subunits. Substrate specificity experiments indicated that the purified kinase is capable of using all tested nucleosides as substrates. N-terminal sequencing of the Avena protein revealed that 87% of the 23 amino acids sequenced were identical to the human Nm23 protein, a nucleoside diphosphate kinase identified as a possible tumor metastasis suppressor and transcriptional activator of the myc oncogene.

G-proteins in etiolated Avena seedlings. Possible phytochrome regulation

The molecular mechanism of light signal transduction in plants mediated by the photosensor phytochrome is not well understood. The possibility that phytochrome initiates the signal transduction chain by modulating a G-protein-like receptor is examined in the present work. Etiolated Avena seedlings contain G-proteins as examined in terms of the binding of GTP as well as by cross-reaction with mammalian G-protein antibodies. The binding of GTP was regulated in vivo by red/far-red light. The possible involvement of G-proteins in the phytochrome-mediated signal transduction in etiolated Avena seedlings has been implicated from the study of the light regulated expression of the Cab and phy genes.

Chromophore topography and secondary structure of 124-kilodalton Avena phytochrome probed by Zn2(+)-induced chromophore modification

The relative extent of chromophore exposure of the red-absorbing (Pr) and far-red-absorbing (Pfr) forms of 124-kDa oat phytochrome and the secondary structure of the phytochrome apoprotein have been investigated by using zinc-induced modification of the phytochrome chromophore. The absence of bleaching of Pr in the presence of a 1:1 stoichiometric ratio of zinc ions, in contrast to extensive spectral bleaching of the Pfr form, confirms previous reports of differential exposure of the Pfr chromophore relative to the Pr chromophore [Hahn et al. (1984) Plant Physiol. 74, 755-758]. The emission of orange fluorescence by zinc-chelated Pfr indicates that the Pfr chromophore has been modified from its native extended/semi-extended conformation to a cyclohelical conformation. Circular dichroism (CD) analyses of native phytochrome in 20 mM Tris buffer suggests that the Pr-to-Pfr phototransformation is accompanied by a photoreversible change in the far-UV region consistent with an increase in the alpha-helical folding of the apoprotein. The secondary structure of phytochrome in Tris buffer, as determined by CD, differs slightly from that of phytochrome in phosphate buffer, suggesting that phytochrome is a conformationally flexible molecule. Upon the addition of a 1:1 molar ratio of zinc ions to phytochrome, a dramatic change in the CD of the Pfr form is observed, while the CD spectrum of the Pf form is unaffected. Analysis of the bleached Pfr CD spectrum by the method of Chang et al. (1978) reveals that chelation with zinc ions significantly alters the secondary structure of the phytochrome molecule, specifically by increasing the beta-sheet content primarily at the expense of alpha-helical folding.(ABSTRACT TRUNCATED AT 250 WORDS)

Non-responsiveness to hepatitis-B vaccination: revaccination and immunogenetic typing

The variation in immune responses to standard inoculation of the hepatitis-B virus vaccine suggest that host factors influence response in ways that are not presently understood. We studied 25 low/nonresponding health care workers (anti-HBs titer less than 50 IU/l) after the third inoculation of an experimental hepatitis-B vaccine to determine their immune status (through lymphocyte phenotypes) and HLA type. After application of a fourth inoculation, the seroconverting subjects showed only low anti-HBs levels; three male subjects remained anti-HBs negative. Twelve months after the fourth inoculation only 9 of 25 subjects (36%) maintained anti-HBs titer greater than 10 IU/l. Almost all subjects had normal B-cell and CD-4 and CD-8 counts and ratios. Relative to other European populations HLA-A-10 (P less than 0.05), B-12 (P less than 0.025), CW-5 (P less than 0.05), DR-3 (P less than 0.025), and DR-5 (P less than 0.025) were increased, whereas DR-2 (P less than 0.05) was decreased. However, after correction of the P-values for the number of HLA antigens determined, these differences were no longer significant. Furthermore, these HLA types were not the same as those reported in other studies (except for DR-3). We suggest that larger sample sizes or even not yet available immunogenetic markers will be required to prove an "immunogenetic background" in low/nonresponders, if it exists.

Complexity of the early genetic response to growth factors in mouse fibroblasts

Genes whose expression is growth factor regulated are likely to be important components in the mechanisms controlling cell proliferation and differentiation. With the aim of identifying some of those genes, a lambda cDNA library was prepared with poly(A)+ RNA from quiescent NIH 3T3 cells stimulated with serum for 4 h in the presence of cycloheximide. Differential screening of approximately 200,000 recombinant phage plaques revealed 2,540 clones that cross hybridized preferentially with [32P]cDNA derived from RNA of stimulated cells rather than with cDNA derived from nonstimulated cells. Cross hybridization of these clones identified 82 independent sequences, including c-fos and c-myc. Seventy-one clones were further studied. Analysis of the changes in transcription and mRNA levels after serum stimulation demonstrated that the kinetics and extent of the induction vary dramatically between the different genes. Cycloheximide in all cases superinduced the mRNA levels by two mechanisms, inhibiting the shutoff of transcription and prolonging the half-lives of the mRNAs. Our results showed that induction of proliferation is accompanied by the onset of a complex genetic program.

German experimental hepatitis B vaccine--influence of variation of dosage schedule, sex and age differences on immunogenicity in health care workers

Of the medical staff of our hospital 217 members at high risk for hepatitis B were immunized with an experimental hepatitis B vaccine and anti-HBs titers used to study the influence of two dosage schedules, age, and sex on immunogenicity. Participants were 34 years of age (mean; range, 20-61); they were divided into two groups and vaccinated three times. Group A received 42 micrograms HBsAg for each vaccination. Group B received 84 micrograms for the first and 21 micrograms for the second and third vaccinations. The seroconversion rate was 32.7% after the first, 78.8% after the second, and 95.7% after the third vaccination. The participants who failed to produce anti-HBs titer (3 IU/l; n = 9) or whose anti-HBs titers were below 50 IU/l (n = 31) were vaccinated a fourth time. Only mild side effects of injections were observed in a third of all participants, usually in the form of a sore arm. Between groups A and B there were no significant differences as far as the seroconversion rate and anti-HBs titer were concerned. Nonresponders plus low-responders accounted for 19%. Female participants produced a markedly higher anti-HBs titer than males, and the female/male ratio among non- and low-responders was 1:2; among nonresponders, 1:2.5. There was a negative correlation of the anti-HBs titer with the age of the participants. These results not only have practical consequences for revaccination policy, but also offer the opportunity to further study the genetic regulation of the immune response to a complex peptide antigen in man.

Caudal medullary expiratory neurone and internal intercostal nerve discharges in the cat: effects of lung inflation

In midcollicular decerebrate, thoracotomized, paralysed cats that were ventilated by a cycle-triggered pump and had an expiratory load, recordings were taken from expiratory neurones in the nucleus retroambigualis of the caudal medulla and from the internal intercostal nerves at T8-T9 levels. Expiratory neurone and internal intercostal activities had augmenting patterns of two types: (a) step-ramp (one-third of the neurones): a large initial increase of activity synchronous with inspiratory termination, followed by a ramp increase throughout the expiratory phase; (b) ramp (two-thirds of the neurones): a steady rise of activity without a sharp initial increase, discharge usually starting after a delay (as much as several hundred milliseconds) from the onset of expiration. Both types of unit pattern could occur together with each type of internal intercostal pattern. At the end of expiration, unit activity shut off abruptly just prior (0-120 ms) to the onset of phrenic discharge. The effects of pulmonary afferent discharge on unit and internal intercostal activities were evaluated by use of inflation tests: withholding inflation during the preceding inspiratory phase; maintaining inflation at the end-inspiratory level during expiration. Both tests produced lengthening of expiratory phase duration (TE), but their effects on activity differed. Following no-inflation during inspiration, the discharge onset delay was lengthened for most ramp neurones, but for only a minority of step-ramp neurones; the slope of activity augmentation did not change on the average; and the peak (end-expiratory) discharge frequency was only slightly increased. The predominant effect of maintained expiratory inflation was reduction of activity slope for ramp neurones and for a minority of step-ramp neurones, as well as increase of peak frequency; there was a moderate increase of discharge onset delay for ramp neurones, but not for step-ramp neurones. The lengthening of TE produced by no-inflation in the preceding inspiration was associated with lengthening of the durations of both the discharge onset delay and the discharge burst, but there was no correlation between changes of these two variables. We observed a 'reversal phenomenon': moderate inflation facilitated activity, whereas higher inflation levels depressed activity, as demonstrated by: comparison of effects of maintained expiratory deflation (removal of the expiratory load) and of maintained expiratory inflation, both of which reduced activity; comparison of effects of phasic expiratory inflations having different magnitudes.(ABSTRACT TRUNCATED AT 400 WORDS)