The Perils of Riding Motocross: A Summary of this Extensive, Prospective Study

Background

Motocross is a high-risk form of motorbiking where serious injuries occur regularly, although little data have been collected to illustrate this relationship. Over 5 years, teams from RJAH Oswestry and RSH sought to demonstrate the impact of Motocross on orthopaedic presentation and workload.

Method

Data were collected prospectively over 5 years including 615 orthopaedic injuries associated with both recreational and competitive motocross.

Results

An increase in injury and operation frequency was observed, young males were identified as the highest risk participant. This was evident over winter and weekends, during the competitive racing season. A variety of injuries have been implicated, some with life threatening or disabling consequences.

Conclusion

Motocross has seen exponential growth in popularity with increases in injuries and operations. This implicates major impacts on finances and healthcare, especially at times of seasonal vulnerability. The authors encourage event organisers to explore the avenues of rider safety in this increasingly popular sport.

Report on the CCT Supplementary comparison S2 on thermal conductivity measurements of insulating materials by guarded hot plate

Seven National Metrology Institutes (NMIs) from France, United States, United Kingdom, Russia, Mexico, China and Germany participated in an inter-laboratory comparison on thermal conductivity measurements by the Guarded Hot Plate method. This action was part of a series of supplementary inter-laboratory comparisons (including infrared spectral emittance and thermal diffusivity) sponsored by the Consultative Committee on Thermometry (CCT) Task Group on Thermophysical Quantities (TG-ThQ). The objective of this collaborative work was to strengthen the consistency of thermal conductivity measurements carried out worldwide on low conductive materials. Measurements were conducted successively by all participants on the same sets of specimens of insulating materials (mineral wool and expanded polystyrene) at temperatures ranging from 10 °C to 40 °C, according to the International Standard ISO 8302. This protocol aimed to minimize issues of material variability by circulating the same pairs of specimens among the laboratories following the strict format of a round-robin test program. More than 120 data points (combinations of material, thickness and temperature) were compared. 92 % of the data points were in agreement, with differences to weighted mean values less than the expanded uncertainties calculated from the individual NMI uncertainties and uncertainties related to the comparison process.

Calibration of thermocouple-based scanning thermal microscope in active mode (2ω method)

We present a procedure dedicated to the calibration of a scanning thermal microscopy probe operated in an active mode and a modulated regime especially for the measurement of solid material thermal conductivities. The probe used is a microthermocouple wire mounted on a quartz tuning fork. Measurements on reference samples are performed successively in vacuum and ambient air conditions revealing a clear difference in the dependence of the thermal interaction between the probe and the sample on the sample properties. Analytical modeling based on the resolution of the heat equation in the wire probe and a description of the thermal interaction using a network of thermal conductances are used to fit experimental data and analyze this difference. We have experimentally verified that the effective thermal contact radius of the probe tip depends on the sample thermal conductivity in ambient conditions, whereas it remains constant in vacuum. We have defined the measurement range of the technique based on the decrease in the probe sensitivity at high thermal conductivities. Considering the experimental noise of our electrical device, it is shown that the maximum measurable value of thermal conductivity is near 23 W m^-1 K^-1 in vacuum and 37 W m^-1 K^-1 in ambient air conditions. Moreover, the lowest uncertainties are obtained for thermal conductivities below 5 W m^-1 K^-1 typically.

Development of an air flow calorimeter prototype for the measurement of thermal power released by large radioactive waste packages

The estimation and control of the thermal power released by the radioactive waste packages are a key parameter in the management of radioactive waste geological repository sites. In the framework of the European project "Metrology for decommissioning nuclear facilities," the French National Agency of Radioactive Waste Management (ANDRA) collaborates with Laboratoire National de Métrologie et D'essais in order to measure the thermal power up to 500 W of typical real size radioactive waste packages (of at least 0.175 m³) with an uncertainty better than 5% by using a measurement method traceable to the international system of units. One of the selected metrological approaches is based on the principles of air flow calorimetry. This paper describes in detail the development of the air flow calorimeter prototype as well as the design of a radioactive waste package simulator used for its calibration. Results obtained from the calibration of the calorimeter and from the determination of thermal powers are presented here with an investigation of the measurement uncertainties.

[Neurodevelopmental outcome of very low birth weight infants born at the Perinatal Centre in Ulm, Germany]

BACKGROUND

Since 2006 an assessment of the neurodevelopmental outcome of very low birth weight infants (VLBWI) at a corrected age of 2 years is mandatory for every perinatal centre in Germany. The aim of our study was to check how complete these assessments were performed in our population of infants born at our perinatal centre and receiving treatment within our local neonatal network. Furthermore, the data obtained will be used for prenatal consultations. Another objective was to identify risk factors for adverse neurodevelopmental outcomes.

METHODS

All VLBWI were invited for a follow-up exam using the Bayley Scales of Infant Development II (BSID-II) or III (BSID-III), or Griffiths Mental Developmental Scales) at 2 years corrected age. The results of children assessed by other institutions were collected.

RESULTS

142 (69.3%) of the 205 VLBWI, born and finally discharged alive at the perinatal centre in Ulm were assessed at a median (minimum - maximum) corrected age of 23 (18-27) months. The BSID-II Psychomotor Development Index (PDI) 91 was (< 50-128) (n=115), the BSID-II Mental Development Index (MDI) was 87 (< 50-134) (n=96), BSID-III MDI 95 (60-112) (n=29) and the Griffiths Score was 93 (67-140) (n=17). Severe disability was diagnosed in 36 (25.4%) of the children studied. Gestational age and higher grade intraventricular haemorrhage were associated independently with severe disability.

CONCLUSIONS

It is very difficult to achieve a high rate of follow-up examinations in preterm infants <1,500 g in a neonatal network. Severe impairment in VLBWI is not rare. Improving neurodevelopmental outcome remains a challenge.

Essential role of grim-led programmed cell death for the establishment of corazonin-producing peptidergic nervous system during embryogenesis and metamorphosis in Drosophila melanogaster

In Drosophila melanogaster, combinatorial activities of four death genes, head involution defective (hid), reaper (rpr), grim, and sickle (skl), have been known to play crucial roles in the developmentally regulated programmed cell death (PCD) of various tissues. However, different expression patterns of the death genes also suggest distinct functions played by each. During early metamorphosis, a great number of larval neurons unfit for adult life style are removed by PCD. Among them are eight pairs of corazonin-expressing larval peptidergic neurons in the ventral nerve cord (vCrz). To reveal death genes responsible for the PCD of vCrz neurons, we examined extant and recently available mutations as well as RNA interference that disrupt functions of single or multiple death genes. We found grim as a chief proapoptotic gene and skl and rpr as minor ones. The function of grim is also required for PCD of the mitotic sibling cells of the vCrz neuronal precursors (EW3-sib) during embryonic neurogenesis. An intergenic region between grim and rpr, which, it has been suggested, may enhance expression of three death genes in embryonic neuroblasts, appears to play a role for the vCrz PCD, but not for the EW3-sib cell death. The death of vCrz neurons and EW3-sib is triggered by ecdysone and the Notch signaling pathway, respectively, suggesting distinct regulatory mechanisms of grim expression in a cell- and developmental stage-specific manner.

[Maintenance of health and relief for caregivers of elderly with dementia by using "initial case management": experiences from the Lighthouse Project on Dementia, Ulm, ULTDEM-study]

BACKGROUND

When facing the well-known demographic development with an increasing number of people suffering from dementia, there is a need of programmes to support nursing relatives and care at home. Many support services have been established in the past few years but they are rarely used by the relatives and the patients. The purpose of the Lighthouse Project Ulm (ULTDEM Study) was to prove the effectiveness of a single advisory approach in order to provide support services after care level classification and to relieve the burden placed on relatives caring for family members suffering from dementia ("initial case management").

METHODS

The ULTDEM Study is a prospective, open, randomized, controlled, interventional study with different parallel outcome measures (burden of caring, quality of life and mood). After the randomization, the interventional group was given comprehensive, individual advice about available treatment possibilities for dementia patients. Control group participants received standard treatment. Inclusion criteria were application of a care level (0 or 1) as well as dementia diagnosis. All participants (patients/relatives) underwent an initial and a 6 month comprehensive assessment.

RESULTS

Our results show that a single advisory approach does not lead to a significant difference in outcome measures in interventional and control groups. Those tendencies described have to be interpreted as clinically not relevant. Although utilization of support services increases, it remains similar in both study groups. A confirmatory interpretation has not been possible due to a lack of adjustment to the findings regarding multiple testing and an insufficient degree of recruitment. Possible causes will be discussed such as premature intervention during the course of the disease, a lack of intervention blinding, recruitment bias and lack of an influence on adherence with regard to the use of support services.

IMPLICATIONS

The study demonstrates that there is a substantial information deficit for persons affected by dementia and their relatives. Innovative ways still have to be developed to ensure that this information actually reaches the target audience.

Drosophila caspases involved in developmentally regulated programmed cell death of peptidergic neurons during early metamorphosis

A great number of obsolete larval neurons in the Drosophila central nervous system are eliminated by developmentally programmed cell death (PCD) during early metamorphosis. To elucidate the mechanisms of neuronal PCD occurring during this period, we undertook genetic dissection of seven currently known Drosophila caspases in the PCD of a group of interneurons (vCrz) that produce corazonin (Crz) neuropeptide in the ventral nerve cord. The molecular death program in the vCrz neurons initiates within 1 hour after pupariation, as demonstrated by the cytological signs of cell death and caspase activation. PCD was significantly suppressed in dronc-null mutants, but not in null mutants of either dredd or strica. A double mutation lacking both dronc and strica impaired PCD phenotype more severely than did a dronc mutation alone, but comparably to a triple dredd/strica/dronc mutation, indicating that dronc is a main initiator caspase, while strica plays a minor role that overlaps with dronc's. As for effector caspases, vCrz PCD requires both ice and dcp-1 functions, as they work cooperatively for a timely removal of the vCrz neurons. Interestingly, the activation of the Ice and Dcp-1 is not solely dependent on Dronc and Strica, implying an alternative pathway to activate the effectors. Two remaining effector caspase genes, decay and damm, found no apparent functions in the neuronal PCD, at least during early metamorphosis. Overall, our work revealed that vCrz PCD utilizes dronc, strica, dcp-1, and ice wherein the activation of Ice and Dcp-1 requires a novel pathway in addition to the initiator caspases.

Inactivation and elimination of human enteric viruses by Pacific oysters

AIMS

To investigate the comparative elimination of three different human enterically transmitted viruses [i.e. hepatitis A virus (HAV), norovirus (NoV) and poliovirus (PV)] and inactivation of HAV and PV by Pacific oysters.

METHODS AND RESULTS

New Zealand grown Pacific oysters (Crassostrea gigas) were allowed to bioaccumulate HAV, NoV and PV. Samples of oyster gut, faeces and pseudofaeces were then analysed by using real-time RT-PCR to determine the amount of viral RNA and cell culture methods to identify changes in the number of plaque forming units. The results suggest that the majority of the PV present in the oyster gut and oyster faeces is noninfectious, while in contrast, most of the HAV detected in the oyster gut are infectious. Depuration experiments identified a large drop in the count of PV in the gut over a 23-h cleansing period, whereas the levels of HAV and NoV did not significantly decrease.

CONCLUSIONS

Human enterically transmitted viruses are eliminated and inactivated at different rates by Pacific oysters.

SIGNIFICANCE AND IMPACT OF STUDY

The research presented in this article has implications for risk management techniques that are used to improve the removal of infectious human enteric viruses from bivalve molluscs.

The deubiquitinase emperor's thumb is a regulator of apoptosis in Drosophila

We have characterized the gene emperor's thumb (et) and showed that it is required for the regulation of apoptosis in Drosophila. Loss-of-function mutations in et result in apoptosis associated with a decrease in the concentration of DIAP1. Overexpression of one form of et inhibits apoptosis, consistent with et having an anti-apoptotic function; however, overexpression of a second form of et induces apoptosis, indicating that the two forms of et may have competing functions. et encodes a protein deubiquitinase, suggesting it regulates apoptosis by controlling the stability of apoptotic regulatory proteins.

Identification of novel genes involved in light-dependent CRY degradation through a genome-wide RNAi screen

Circadian clocks regulate many different physiological processes and synchronize these to environmental light:dark cycles. In Drosophila, light is transmitted to the clock by a circadian blue light photoreceptor CRYPTOCHROME (CRY). In response to light, CRY promotes the degradation of the circadian clock protein TIMELESS (TIM) and then is itself degraded. To identify novel genes involved in circadian entrainment, we performed an unbiased genome-wide screen in Drosophila cells using a sensitive and quantitative assay that measures light-induced degradation of CRY. We systematically knocked down the expression of approximately 21,000 genes and identified those that regulate CRY stability. These genes include ubiquitin ligases, signal transduction molecules, and redox molecules. Many of the genes identified in the screen are specific for CRY degradation and do not affect degradation of the TIM protein in response to light, suggesting that, for the most part, these two pathways are distinct. We further validated the effect of three candidate genes on CRY stability in vivo by assaying flies mutant for each of these genes. This work identifies a novel regulatory network involved in light-dependent CRY degradation and demonstrates the power of a genome-wide RNAi approach for understanding circadian biology.

Differential requirements for the Pax6(5a) genes eyegone and twin of eyegone during eye development in Drosophila

In eye development the tasks of tissue specification and cell proliferation are regulated, in part, by the Pax6 and Pax6(5a) proteins respectively. In vertebrates, Pax6(5a) is generated as an alternately spliced isoform of Pax6. This stands in contrast to the fruit fly, Drosophila melanogaster, which has two Pax6(5a) homologs that are encoded by the eyegone and twin of eyegone genes. In this report we set out to determine the respective contributions that each gene makes to the development of the fly retina. Here we demonstrate that both eyg and toe encode transcriptional repressors, are expressed in identical patterns but at significantly different levels. We further show, through a molecular dissection of both proteins, that Eyg makes differential use of several domains when compared to Toe and that the number of repressor domains also differs between the two Pax6(5a) homologs. We predict that these results will have implications for elucidating the functional differences between closely related members of other Pax subclasses.

Antidepressant effects of augmentative transcranial magnetic stimulation: randomised multicentre trial

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) has been proposed as a new treatment option for depression. Previous studies were performed with low sample sizes in single centres and reported heterogeneous results.

AIMS

To investigate the efficacy of rTMS as augmentative treatment in depression.

METHOD

In a randomised, double-blind, sham-controlled multicentre trial 127 patients with moderate to severe depressive episodes were randomly assigned to real or sham stimulation for 3 weeks in addition to simultaneously initiated antidepressant medication.

RESULTS

We found no difference in the responder rates of the real and the sham treatment groups (31% in each) or in the decrease of the scores on the depression rating scales.

CONCLUSIONS

The data do not support previous reports from smaller samples indicating an augmenting or accelerating antidepressant effect of rTMS. Further exploration of the possible efficacy of other stimulation protocols or within selected sub-populations of patients is necessary.

Type II diabetes mellitus and impaired glucose regulation in Caucasian children and adolescents with obesity living in Germany

BACKGROUND

Recent studies reported an increased prevalence of type II diabetes mellitus in obese children and adolescents, especially in specific ethnic subgroups. The aim of this study was to determine the prevalence of type II diabetes mellitus and impaired glucose regulation in a large group of Caucasian children and adolescents with obesity living in Germany.

PATIENTS AND METHODS

A total of 520 subjects (237 boys, 283 girls) (mean age: 14.0+/-2.0 y (range 8.9-20.4 y)) with a BMI>97th percentile, BMI-SDS: 2.7+/-0.5 (range 1.9-4.6), who were consecutively admitted to an in-patient obesity unit participated in the study. A 2-h oral glucose tolerance test (1.75 mg of glucose per kilogram of body weight) was performed before entering a weight-loss program and capillary blood glucose concentrations were measured. Patients were categorized into normal glucose regulation, impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and diabetes. In addition, fasting venous blood was taken to determine the circulating insulin, C-peptide and lipids. Insulin resistance was estimated by homeostatic model assessment.

RESULTS

Type II diabetes was present in 1.5% (n=8) of the patients, two patients were admitted with already diagnosed type II diabetes and six patients were identified with yet unknown diabetes. IFG was detected in 3.7% (n=19) and IGT in 2.1% (n=11) of the patients. All together, in 6.7% (n=35) (95% confidence interval: 4.7-9.2%) of the patients, impaired glucose regulation (IFG, IGT) or diabetes was identified. These patients had a higher BMI-SDS, higher levels of fasting insulin and C-peptide and a higher insulin resistance index than the patients with normal glucose regulation. Risk factors for the occurrence of impaired glucose regulation were a BMI-SDS>2.5 as well as a positive parents' history for diabetes.

CONCLUSIONS

This is the first report on the prevalence of type II diabetes in a large cohort of Caucasian children and adolescents with obesity living in Europe. Impaired glucose regulation and type II diabetes were present in a substantial proportion of the patients studied. Screening for diabetes in severely obese children and adolescents (BMI-SDS>2.5) is therefore recommended. Patients identified with impaired glucose regulation need specific treatment programs in order to prevent progression to diabetes.

Antimicrobial expenditures and usage at four university hospitals. Baden-Württemberg Interuniversity Study Group

BACKGROUND

The increasing use of antimicrobiaL drugs is resulting in enormous hospital expenditures. Careful assessment of inappropriate prescribing and a search for more cost-effective treatment strategies are urgently required. Comparisons between hospitals should help identify areas of inappropriate prescribing as well as effective drug use programs, but such analyses may be severely biased if the impact of different case-mixes is not recognized.

PATIENTS AND METHODS

We studied antimicrobial usage and expenditures at four state university hospitals in southwestern Germany and assessed the significance of differences between hospital services after adjustment for patient variables. A prevalence survey was done with review of 2,254 charts of patients admitted to the surgical, medical and pediatric services to obtain information on antimicrobial drug prescription and expenditures in the week preceding the survey.

RESULTS

According to pharmacy data for the year 1994, maximal differences between these hospitals in the antibiotic costs per patient-day were 1.9-fold (surgical services), 1.5-fold (medical services), and 1.6-fold (pediatric services). In a multivariate analysis, adjusted antibiotic prescription prevalence rates did not differ for medical and pediatric service patients, but did differ for surgical service patients (p = 0.03). Similarly, adjusted expenditures per patient-week differed significantly between hospitals for surgical service patients (p = 0.001), but only marginally for medical (p = 0.14) and pediatric (p = 0.05) service patients. The adjusted difference in expenditures between surgical departments was as large as 2.8-fold (95% CI 1.8 to 4.3) and was primarily related to preferential use of expensive iv antimicrobial drugs.

CONCLUSION

In two hospitals, lowest expenditures in either surgery or medicine were associated with active antimicrobial drug use programs suggesting an impact of these programs on drug use and expenditures limited to these services. The identification of such large patient-mix unrelated differences in antimicrobial usage and expenditures offers opportunities for quality improvements and cost reduction.

[Prevalence of cholecystolithiasis in South Germany--an ultrasound study of 2,498 persons of a rural population]

Gallbladder stones represent one of the most common reason for morbidity in western industrial nations. There remains a paucity of exact information regarding the prevalence and risk factors for this disease entity in Germany. As part of a whole-community survey focusing on the prevalence of echinococcosis multilocularis conducted in a population in southwestern Germany (response rate: 66.6%), 2,560 subjects underwent an upper abdominal ultrasound examination at which the presence of gallbladder stones was ascertained. In each case, upper abdominal sonography was performed following completion of a standardized interview. In 62 subjects, the gallbladder could not be adequately visualized due to an insufficient fasting period; the remaining 2,498 subjects (1,326 females, age 38.9 +/- 19.9 years; 1,172 males, age 37.7 +/- 18.8 years) were included in the study collective. Gallbladder stones (sonographically visualized gallbladder stones or history of cholecystectomy for cholecystolithiasis) were found in 196 participants (7.8%; 139 females [10.5%] versus 57 males [4.9%]). Statistical treatment of the data using multiple logistical regression techniques revealed a significant influence of the variables age, gender, body mass index (BMI) and positive family history on the development of gallbladder stones. The prevalence of gallbladder stones in the present study population is lower than figures reported for a study in Brandenburg and at 7.8% is rather low in comparison with other European studies. One explanation may be the low average age of study participants, almost 50% of whom were less than 35 years. Besides age, subjects' gender, BMI and positive family history were identified as significant risk factors.

Gallstone prevalence in Germany: the Ulm Gallbladder Stone Study

The Ulm Gallbladder Stone Study is the first ultrasound-based epidemiologic survey of cholecystolithiasis in the former West Germany. A study population of 1116 blood donors (656 men, age 38.0 +/- 12.0 years; 460 women, age 34.1 +/- 11.2 years) at the Central Blood Bank of the German Red Cross in Ulm was examined between April 1994 and February 1995. Based on age, subjects were assigned to one of four groups (18-30, 31-40, 41-50, and 51-65 years). Following a structured interview of each study subject, an ultrasound examination was carried out and a blood sample obtained for laboratory study. Overall, 6.0% (95% (95% CI: 4.8%-7.6%) of all study subjects (5.8% of the men and 6.3% of the women) exhibited evidence of current or past gallbladder disease (cholelithiasis or history of cholecystectomy). The prevalence of gallbladder disease correlated positively with age, reaching a maximum of 13.7% (9.5-20.0) in the 51- to 65-year-old age group, and also correlated as with body mass index (BMI). Female subjects with previous full-term pregnancies showed a higher prevalence of cholelithiasis, but this difference was not statistically significant for age-adjusted analysis. Subjects with a family history of cholelithiasis were found to suffer from gallstones in 11.5% (8.0-16.7) of cases compared with 4.6% (3.4%-6.3%) of subjects without such family history. Autopsy studies conducted in Germany have shown the prevalence of gallstones to be about 13.1% in men and 33.8% in women. Our sonographic data are relatively low in comparison. This may be due, in part, to the specific selection characteristics inherent in retrospective autopsy studies, such as age distribution and the presence of other pathologic factors associated with increased risk for cholelithiasis. The Ulm data rank in the lower third of the prevalence range reported for European sonographic studies to date. Age, positive family history, and increased BMI all correlated positively with the prevalence of gallbladder disease (P < 0.05). For the study population as a whole, there was no gender-specific increased risk for the development of gallstones.

Gallstone prevalence in relation to smoking, alcohol, coffee consumption, and nutrition. The Ulm Gallstone Study

BACKGROUND

Besides considering well-known risk factors for the development of gallbladder stones, such as age, sex, fecundity, and hereditary predisposition, efforts at prevention have focused increasingly on other factors, such as nicotine, alcohol, and caffeine consumption, as well as general nutrition, which may be modified.

METHODS

A total of 1116 blood donors were examined between April 1994 and February 1995 in the central blood bank of the German Red Cross in Ulm, Germany. Each subject received a questionnaire and underwent to an upper abdominal ultrasound examination.

RESULTS

Gallbladder stone disease (current cholecystolithiasis and history of cholecystectomy) was detailed in 5.8% of the men and 6.3% of the women. Neither regularity nor number of daily meals correlated with the frequency of gallstone disease. Vegetarians (n = 48), as a group, were not found to have gallstones. In relation to the consumption of alcohol, tobacco, or caffeine higher prevalence of cholecystolithiasis was found only in heavy drinkers of coffee (P = 0.051; odds ratio (OR), 1.083; 95% confidence interval (CI), 0.999, 1.174).

CONCLUSION

Results of the present study do not show a definite relationship between nutritional factors and the consumption of alcohol, tobacco, or caffeine and an increased prevalence of gallbladder stone disease.

Submicroscopic deletions at 16p13.3 in Rubinstein-Taybi syndrome: frequency and clinical manifestations in a North American population

Rubinstein-Taybi syndrome (RTS) is a well delineated multiple congenital anomaly syndrome characterised by mental retardation, broad thumbs and toes, short stature, and specific facial features. The recent localisation of the disorder to 16p13.3 and subsequent identification of a submicroscopic deletion of this region in RTS patients led us to screen a large cohort of affected subjects using the RT1 probe. Among 64 patients with clinical evidence of RTS, seven (11%) had a deletion. Another patient had a translocation of the region without evidence of a deletion. The features of coloboma, growth retardation, naevus flammeus, and hypotonia have a positive predictive value for the presence of an RT1 deletion. Because of the relatively low frequency of deletions in RTS, the RT1 probe is useful in diagnostic confirmation, but has limited use as a screening tool.

A randomized trial of roxithromycin in patients with acute leukemia and bone marrow transplant recipients receiving fluoroquinolone prophylaxis

Fluoroquinolone prophylaxis in patients with profound neutropenia may be useful for preventing gram-negative bacterial infection, but it is ineffective against gram-positive bacterial infections in the bloodstream, particularly those caused by streptococci and coagulase-negative staphylococci, which appear to have emerged as significant causes of morbidity, decreased treatment efficacy, and the increased costs of empiric antimicrobial therapy. In a prospective, randomized, open trial, we evaluated the efficacy and safety of oral roxithromycin (150 mg twice daily) as additional antibacterial prophylaxis in 131 adult patients with acute leukemia and bone marrow transplant recipients receiving oral ofloxacin. In comparison with patients given ofloxacin alone, fewer patients receiving ofloxacin plus roxithromycin developed bacteremia caused by viridans group streptococci (incidence, 9 versus 0%; P = 0.03), while the incidence of bacteremia caused by other organisms, the incidence of febrile episodes from any cause, the risk of infection-associated complications (including prolonged or secondary fever, pneumonia, septic shock, need for mechanical ventilation, and/or infection-related death), and antimicrobial usage for therapy were comparable between both groups. Adverse events possibly related to the study drugs were slightly more common among the patients receiving the combination treatment (P = 0.05). Although effective for the prevention of streptococcal bacteremia, the addition of roxithromycin to a fluoroquinolone should not be used routinely as a prophylactic regimen in patients with profound neutropenia, but it might be considered and may be useful for cancer patients with a particularly high risk of streptococcal infection and related complications.

Single-drug oral antibacterial prophylaxis with ofloxacin in BMT recipients

We evaluated the efficacy and safety of a new oral fluoroquinolone, ofloxacin (200 mg twice daily), as antibacterial prophylaxis after BMT in a non-comparative prospective study of patients nursed in either LAF plastic isolators or HEPA filtered single rooms. Of the 101 evaluable patients who were neutropenic (< 500 x 10(6)/l) for a median duration of 20 days, 92 (91%) had febrile episodes of varying length and causes. Infections were documented in 34 patients, of whom 14 had proven bacterial infection (13 with bacteremia and one with pneumonia). Mortality rate within 6 weeks after transplant was 6%. Only one patient died from bacterial infection. Univariate analysis using an array of potentially prognostic factors including the type of isolation was not helpful in identifying significant variables for predicting the development of documented infection. Tolerance was excellent. Oral ofloxacin was associated with a relatively low incidence of documented bacterial infection and related mortality, although it did not obviate the need for frequent empiric antimicrobial therapy due to a high incidence of febrile episodes.

The germ cell-less gene product: a posteriorly localized component necessary for germ cell development in Drosophila

The first cell fate specification process in the Drosophila embryo, formation of the germline precursors, requires posteriorly localized germ plasm. We have cloned a gene, germ cell-less (gcl), required for germline formation. Posterior localization of the gcl messenger RNA (mRNA) requires the function of those genes essential for the localization of both nanos RNA, which specifies the abdomen, and the germ cell determinants. Mothers with reduced gcl function give rise to sterile adult progeny that lack germ cells. In embryos with reduced maternal gcl product, the germ cell precursors fail to form properly. Consistent with this phenotype, gcl protein specifically associates with those nuclei that later become the nuclei of the germ cell precursors. These observations suggest that gcl functions in the germ cell specification pathway.

Localization of vasa, a component of Drosophila polar granules, in maternal-effect mutants that alter embryonic anteroposterior polarity

Cytoplasm at the posterior pole of the early Drosophila embryo, known as polar plasm, serves as a source of information necessary for germ cell determination and for specification of the abdominal region. Likely candidates for cytoplasmic elements important in one or both of these processes are polar granules, organelles concentrated in the cortical cytoplasm of the posterior pole. Females homozygous for any one of the maternal-effect mutations, tudor, oskar, staufen, vasa, or valois give rise to embryos that lack localized polar granules, fail to form the germ cell lineage and have abdominal segment deletions. Using antibodies against a polar granule component, the vasa protein, we find that vasa synthesis or localization is affected by these mutations. In vasa mutants, synthesis of vasa protein is absent or severely restricted. In oskar and staufen mutant females, vasa synthesis appears normal, but the vasa protein is not localized. In tudor and valois mutant females, vasa is localized to the posterior pole of oocytes, but this localization is lost following egg activation. In addition to the posterior localized vasa, there is a low level of vasa distributed throughout the embryo. A function for this distributed vasa is postulated based on the observation that embryos from Bicaudal-D mothers, in which abdominal determinants are incorrectly localized to the anterior pole, do not show any ectopic vasa localization, though abdomen development at the anterior end depends on the amount of vasa protein in the embryo.

A protein component of Drosophila polar granules is encoded by vasa and has extensive sequence similarity to ATP-dependent helicases

Determinants of pole cells, which are precursors of the germ line, are provided maternally and are localized to the posterior pole of the Drosophila egg, as are polar granules. It has been hypothesized that certain RNA molecules associated with polar granules may be necessary for pole cell determination. Using a monoclonal antibody (Mab46F11) against polar granules, we have cloned the gene for one of their components. This gene turns out to be vasa, which is required maternally for the formation of polar granules and germ cells. This polar granule component shows significant sequence similarity to eIF-4A, a translation initiation factor that binds to mRNA, and to other helicases.

Identification of a component of Drosophila polar granules

Information necessary for the formation of pole cells, precursors of the germ line, is provided maternally and localized to the posterior pole of the Drosophila egg. The maternal origin and posterior localization of polar granules suggest that they may be associated with pole cell determinants. We have generated an antibody (Mab46F11) against polar granules. In oocytes and early embryos, the Mab46F11 antigen is sharply localized to the posterior embryonic pole. In pole cells, it becomes associated with nuclear bodies within, and nuage around, the nucleus. Immunoreactivity remains associated with cells of the germ line throughout the life cycle of both males and females. This antibody recognizes a 72–74 × 10(3) Mr protein and is useful both as a pole lineage marker and in biochemical studies of polar granules.

Evidence for a secretory form of the cellular prion protein

The biogenesis of hamster brain prion protein (PrP) has been studied by expression of RNA transcribed from a full-length PrP cDNA in Xenopus oocytes and cell-free systems. Earlier studies in the wheat germ cell-free system showed that one form of PrP is a transmembrane protein that spans the bilayer at least twice [Hay, B., Barry, R. A., Lieberburg, I., Prusiner, S. B., & Lingappa, V. R. (1987) Mol. Cell. Biol. 7, 914-920]. We now report that PrP can also exist as a secreted protein. SP6 PrP RNA microinjected into Xenopus oocytes produced two forms of PrP: one that remained in the cell and another that was secreted into the medium. Cell-free translation studies in rabbit reticulocyte lysates supplemented with microsomal membranes gave similar results: while one form of PrP was found as an integral membrane protein spanning the membrane at least twice, another form of PrP was found to be completely translocated to the microsomal membrane vesicle lumen. Both the membrane and secretory forms of PrP appear to be generated from the same pool of nascent chains. The mechanism governing the alternative fates of nascent PrP remains to be elucidated but may have significance for understanding the pathogenesis of scrapie and other prion diseases.

Developmental expression of prion protein gene in brain

Synthesis of the cellular isoform of the prion protein (PrPC) was found to be regulated during development of the hamster brain. PrP poly A(+) RNA was readily detectable 10 days postpartum; after 20 days of age, no change in its level could be detected through 13 months of age. Low levels of PrP poly A(+) RNA were detectable 1 day after birth. By contrast, myelin basic protein poly A(+) RNA was found at high levels in brain at 30 days of age and thereafter declined steadily. Using monospecific PrP antisera, immunoprecipitable cell-free translation products were detected at low levels 2 days after birth and increased progressively through 10 days of age. How the levels of PrP mRNA participate in brain development and function remains to be established.

Biogenesis and transmembrane orientation of the cellular isoform of the scrapie prion protein [published errratum appears in Mol Cell Biol 1987 May;7(5):2035]

Considerable evidence suggests that the scrapie prion protein (PrP) is a component of the infectious particle. We studied the biogenesis and transmembrane orientation of an integral-membrane form of PrP in a cell-free transcription-linked translation-coupled translocation system programmed with a full-length PrP cDNA cloned behind the SP6 promoter. Translation of SP6 transcripts of the cDNA or of native mRNA from either normal or infected hamster brain in the absence of dog pancreas membranes resulted in the synthesis of a single PrP immunoreactive polypeptide (each polypeptide was the same size; Mr, 28,000), as predicted from the known sequence of the coding region. In the cotranslational presence of membranes, two additional forms were observed. Using peptide antisera specific to sequences from the amino- or the carboxy-terminal domain of PrP together with proteinase K or endoglycosidase H digestion or both, we showed that one of these forms included an integrated and glycosylated form of PrP (Mr = 33,000) which spans the bilayer twice, with domains of both the amino and carboxy termini in the extracytoplasmic space. By these criteria, the other form appeared to be an unglycosylated intermediate of similar transmembrane orientation. The PrP cell-free translation products did not display resistance to proteinase K digestion in the presence of nondenaturing detergents. These results suggest that the PrP cell-free translation products most closely resemble the normal cellular isoform of the protein, since its homolog from infected brain was proteinase K resistant. The implications of these findings for PrP structure and function are discussed.

Voltage-dependent calcium and calcium-activated potassium currents of a molluscan photoreceptor

Two-microelectrode voltage clamp studies were performed on the somata of Hermissenda Type B photoreceptors that had been isolated by axotomy from all synaptic interaction as well as any impulse-generating (i.e., active) membrane. In the presence of 2-10 mM 4-aminopyridine (4-AP) and 100 mM tetraethylammonium ion (TEA), which eliminated two previously described voltage-dependent potassium currents (IA and the delayed rectifier), a voltage-dependent outward current was apparent in the steady state responses to command voltage steps more positive than -40 mV (absolute). This current increased with increasing external Ca++. The magnitude of the outward current decreased and an inward current became apparent following EGTA injection. Substitution of external Ba++ for Ca++ also made the inward current more apparent. This inward current, which was almost eliminated after being exposed for approximately 5 min to a solution in which external Ca++ was replaced with Cd++, was maximally activated at approximately 0 mV. Elevation of external potassium allowed the calcium (ICa++) and calcium-dependent K+ (IC) currents to be substantially separated. Command pulses to 0 mV elicited maximal ICa++ but no IC because no K+ currents flowed at their new reversal potential (0 mV) in 300 mM K+. At a holding potential of -60 mV, which was now more negative than the potassium equilibrium potential, EK+, in 300 mM K+, IC appeared as an inward tail current after positive command steps. The voltage dependence of ICa++ was demonstrated with positive steps in 100 mM Ba++, 4-AP, and TEA. Other data indicated that in 10 mM Ca++, IC underwent pronounced and prolonged inactivation whereas ICa++ did not. When the photoreceptor was stimulated with a light step (with the membrane potential held at -60 mV), there was also a prolonged inactivation of IC. In elevated external Ca++, ICa++ also showed similar inactivation. These data suggest that IC may undergo prolonged inactivation due to a direct effect of elevated intracellular Ca++, as was previously shown for a voltage-dependent potassium current, IA. These results are discussed in relation to the production of training-induced changes of membrane currents on retention days of associative learning.

Depolarization-induced effects of Ca2+-calmodulin-dependent protein kinase injection, in vivo, in single neurons of cat motor cortex

Intracellular injection of calcium-calmodulin-dependent protein kinase followed by depolarization and depolarization-elicited impulse activity increased input resistance of neurons of the motor cortex of cats. Protein kinase alone or depolarization in the absence of protein kinase did not produce this effect. An analogous increase of input resistance can be produced in the type B photoreceptor of Hermissenda by applying protein kinase and sufficient depolarization to increase calcium conductance and internal Ca2+ concentration. Given previous studies linking changes in both types of neurons to the development of conditioning, the results suggest the possibility of shared biochemical steps in mechanisms of neuronal adaptation by vertebrate and invertebrate species.