Factors associated with perceived Anaplasma marginale infection and clinical anaplasmosis cases on beef operations in California

Bovine anaplasmosis is a tick-borne disease caused by Anaplasma marginale in the United States. The objective of this study was to use a survey tool to generate information for beef operations in California on anaplasmosis prevention and control management, including to what extent management activities were informed by perceived herd-level exposure to A. marginale infection or occurrence of clinical anaplasmosis cases. We mailed 2,621 questionnaires with questions on Anaplasma status, herd demographics, anaplasmosis control and prevention measures, and environmental factors to beef ranchers in California in October 2020. Survey-weighted chi-square tests were used to compare management differences according to perceived Anaplasma infection status. Generalized estimating equations (GEEs) were used to analyze whether region of California, management practices, or environmental factors were associated with reported clinical cases of anaplasmosis in the previous five years. A total of 466 questionnaires describing 749 herds were obtained and used in this study. Use of management measures, including deliberate exposure of calves to ticks, vaccination for Anaplasma, infection control through antibiotics in feed, maintaining a completely closed herd, blood testing for Anaplasma on all herd additions, and taking no anaplasmosis control and prevention measures, were significantly different between herds with or without perceived A. marginale infection based on producers' self-declared status. The overall perceived prevalence for Anaplasma infection and reported clinical cases of anaplasmosis at the herd level was 26.0 % (95 % CI: 24.3-27.7 %) and 17.1 % (95 % CI: 15.6-18.6 %) respectively, with the highest perceived infection and case numbers reported in the Central Coast region. In the GEE model, higher odds of reporting clinical cases of anaplasmosis in the previous five years were observed in cattle located in the Central Coast region, cattle within a large herd, cattle that are treated with tick/fly control, cattle in a completely closed herd, and cattle receiving Anaplasma vaccine. Anaplasma infection and bovine anaplasmosis status may be underestimated in beef herds in California based on previous study results. Changing needles between cattle after injections and conducting blood testing for Anaplasma on herd additions are important Anaplasma management measures that are infrequently implemented in beef herds in California. The results show a need for producer education to improve producers' awareness of bovine anaplasmosis and implement proper measures for disease control and prevention.

Data is the new oil. How Covid-19 boosted information transparency in Austria

Background

Austria has no tradition of sharing administrative or routine (health) data collected by public authorities with researchers and accordingly no corresponding data infrastructure exists. Triggered by the GDPR and the pandemic situation an increasing demand from scientific institutions to obtain access to health care data (e.g. use of resources, patient pathways) for research purposes emerged. The latest governmental program addressed this fundamental request even before the start of the pandemic mainly because one of the members of the current coalition, the Green Party, values information transparency very high. The abolishment of “professional secrecy” and the promotion of research by enabling a comprehensive secondary use of data are cornerstones of their political agenda.

Mathods

The agenda was boosted by the outbreak of the Covid-19 pandemic that made the need for joint and real-time data-based research into SARS-CoV-2 and COVID-19 evident and eventually led to the establishment of the Covid-19 data platform https://datenplattform-covid.goeg.at in April 2020, which is run by the Austrian National Public Health Institute (GÖG). Since June 2020 national and international scientific institutions can obtain, free of cost, data from the Epidemiological reporting system which includes core information on COVID-19 infections in Austria. Institutions need to apply with GÖG for accreditation which is granted (or denied) by the Scientific Advisory Board of the Platform. Data provision is continuously expanded and includes as of now, data on hospital and ICU admissions due to COVID-19 as well as data on SARS-CoV-2 genome sequencing.

Results

In April 2021, 84 institutions (8 international) had applied for access. 60 have been accredited, in line with the rules of procedure (incl. a plausibility check of the applicant against OECD's Frascati-criteria. In total, nine articles using data from the Covid-19 platform have been submitted to scientific journals.

Key messages

On a national level, the Covid-19 data platform, commissioned by the Austrian Ministry of Health (BMSGPK) is an important step towards a modern and transparent health care administration system.

Covid-19 and the data platform triggered a debate around the need for a (national) data-governance framework balancing benefits from data usage vs the right to data protection of citizens’ health data.

How can the orthopedic surgeon ensure optimal vitamin D status in patients operated for an osteoporotic fracture?

In this narrative review, the role of vitamin D deficiency in the pathophysiology, healing of fragility fractures, and rehabilitation is discussed. Vitamin D status can be assessed by measuring serum 25(OH)-vitamin D level with standardized assays. There is a high prevalence of vitamin D insufficiency (25(OH)D < 50 nmol/l (i.e., 20 ng/mL)) or deficiency (25(OH)D < 25 nmol/l (i.e., 10 ng/mL)) in patients with fragility fractures and especially in those with a hip fracture. The evidence on the effects of vitamin D deficiency and/or vitamin D supplementation on fracture healing and material osseointegration is still limited. However, it appears that vitamin D have a rather positive influence on these processes. The fracture liaison service (FLS) model can help to inform orthopedic surgeons, all caregivers, and fractured patients about the importance of optimal vitamin D status in the management of patients with fragility fractures. Therefore, vitamin D status should be included in Capture the Fracture® program as an outcome of FLS in addition to dual-energy X-ray absorptiometry (DXA) and specific antiosteoporosis medication. Vitamin D plays a significant role in the pathophysiology and healing of fragility fractures and in rehabilitation after fracture. Correction of vitamin D deficiency should be one of the main outcomes in fracture liaison services.

Beurteilungskriterien für die Captopril-Nierenfunktions- szintigraphie mit 99mTc-MAG3

Im Rahmen der Diagnostik der renovaskulären Hypertonie hat die Nierenfunktionsszintigraphie unter Einfluß eines ACE-Hemmers als nichtinvasives Verfahren erhebliche Bedeutung erlangt. Unter Einsatz des Radiopharmazeutikums 99mTc-MAG3 wurden bei 54 Nieren mit angiographisch, klinisch und endokrinologisch gesicherter Diagnose folgende szintigraphischen Parameter isoliert auf ihre Aussagekraft zum Nachweis bzw. Ausschluß einer relevanten Nierenarterienstenose untersucht: parenchymaler Nuklidtransport, Harnabflußsituation, Nierengröße und seitengetrennte Funktionsanteile. Als typischer Befund einer dekompensierten Nierenarterienstenose erwies sich eine ausgeprägte parenchymale Nuklidretention in Kombination mit einer deutlich verzögerten Harnaktivitätsanflutung im Nierenhohlraumsystem. Im Vergleich zur rein visuellen Beurteilung der Sequenzszintigramme erbrachte die Miteinbeziehung zusätzlicher, quantitativer Kriterien im eigenen Patientenkollektiv keine diagnostischen Vorteile. Bei 43 Patienten mit klinischen Hinweisen auf eine renovaskuläre Hypertonie ergab sich mit diesen Kriterien eine Sensitivität von 89%, die Spezifität betrug 88%. Bilateral positive Befunde erwiesen sich als unspezifisch; blieben diese unberücksichtigt, erhöhte sich die Spezifität der Untersuchung auf 100%.

Relaxation und optische Kernspinpolarisation der Protonen in optisch angeregten Anthracen-Kristallen

The influence of optically excited metastable triplet states on the spin lattice relaxation time T1 of protons in anthracene is investigated at room temperature. From the H0-field dependence of T1 in the presence of excited triplets we calculate the hopping time of triplet excitons τc=(5±1) · 10–12 sec. Especially in the low field region a new type of dynamic nuclear polarisation is observed. Triplet excitons, which are excited using unpolarized light produce via optical exciton spin polarisation an optical nuclear spin polarisation. Polarisation factors of more than 1000 are observed. Preliminary experiments with anthracene-tetracene mixed crystals are able to separate relaxation and polarisation effects due to mobile excitons from effects, which don’t need the mobility of excitons.

Protonenspinrelaxation in kristallinem Benzol

Für kristallines Benzol wird nach der halbklassischen Methode die Spingitterrelazationszeit T1 und - für zwei Grenzfälle - auch das 2. Moment 〈Δ ω2〉 berechnet. Erstmals werden auch die intermolekularen Wechselwirkungen quantitativ (mit Hilfe einer elektronischen Rechenmaschine) berücksichtigt. Die berechneten Verhältnisse T1 intra/T1 inter und 〈Δ ω2〉 intra/〈Δ ω2〉inter werden mit entsprechenden Messungen von ANDERSON 1 und von ANDREW 2, die berechneten T1-Werte selbst mit eigenen impulstechnischen Messungen bei 5 Frequenzen zwischen 22 und 88 MHz verglichen. In allen Fällen wurde Übereinstimmung zwischen Rechnung und Messung innerhalb der Fehlergrenzen gefunden. Die gemessene Frequenzabhängigkeit von T1 zeigt, daß sich die Molekülbewegung - sprunghafte Drehungen um die sechszählige Symmetrieachse - durch eine einzige Korrelationszeit charakterisieren läßt.

Kernmagnetische Messungen von Selbstdiffusions-Koeffizienten in Wasser und Benzol bis zum kritischen Punkt

The most commonly used nuclear magnetic resonance spin-echo methods for determining selfdiffusion coefficients D are described; some experimental data are presented for protons in water and in benzene from room temperature up to the critical point. The results are interpreted in terms of the free-volume rate theory of MACEDO and LITOVITZ. The D-value of benzene may be described by a single activation energy. Water, however, shows such behavior only at high temperatures, thus demonstrating the strong influence of hydrogen bonding. The STOKES-EINSTEIN relation between diffusion coefficient and viscosity is well satisfied over that part of the temperature range where viscosity values are available.

Antitumour activity of docetaxel following treatment with the CYP17A1 inhibitor abiraterone: clinical evidence for cross-resistance?

BACKGROUND

Abiraterone and docetaxel are both approved treatments for men with metastatic castration-resistant prostate cancer (mCRPC). Abiraterone pre-docetaxel is currently undergoing evaluation in a phase III study. In vitro studies indicate that taxanes may act by disrupting androgen receptor signalling. We hypothesised that prior abiraterone exposure would adversely impact docetaxel efficacy.

PATIENTS AND METHODS

We retrospectively evaluated activity of docetaxel in mCRPC patients previously treated with abiraterone, using Prostate Cancer Working Group and radiological criteria.

RESULTS

Of the 54 patients treated with abiraterone, 35 subsequently received docetaxel. Docetaxel resulted in a prostate-specific antigen (PSA) decline of ≥50% in nine patients [26%, 95% confidence interval (CI) 13% to 43%], with a median time to PSA progression of 4.6 months (95% CI 4.2% to 5.9%). PSA declines ≥30% were achieved by 13 patients (37%, 95% CI 22% to 55%). The median overall survival was 12.5 months (95% CI 10.6-19.4). All patients who failed to achieve a PSA fall on abiraterone and were deemed abiraterone-refractory were also docetaxel-refractory (N = 8). In the 24 patients with radiologically evaluable disease, partial responses were reported in four patients (11%), none of whom were abiraterone-refractory.

CONCLUSION

The activity of docetaxel post-abiraterone appears lower than anticipated and no responses to docetaxel were observed in abiraterone-refractory patients.

Fluorinated Heteroaromatic Polyethers for Low Dielectric Constant/High Temperature Applications

Synthesis and characterization of three classes of poly(arylene ether oxazole)s and poly(arylene ether thiazole)s with trifluoromethyl substituents in various positions is described. Based on these examples, the influence of the chemical structure of the polymers on properties such as glass transition temperature, solubility, and thermal stability will be discussed. Structural parameters studied are the number and nature of the heteroaromatic rings, the number and position of the trifluoromethyl groups, and the structure (flexibility, polarity) of various linking groups.

Cell-seeded polyurethane-fibrin structures--a possible system for intervertebral disc regeneration

Nowadays, intervertebral disc (IVD) degeneration is one of the principal causes of low back pain involving high expense within the health care system. The long-term goal is the development of a medical treatment modality focused on a more biological regeneration of the inner nucleus pulposus (NP). Hence, interest in the endoscopic implantation of an injectable material took center stage in the recent past. We report on the development of a novel polyurethane (PU) scaffold as a mechanically stable carrier system for the reimplantation of expanded autologous IVD-derived cells (disc cells) to stimulate regenerative processes and restore the chondrocyte-like tissue within the NP. Primary human disc cells were seeded into newly developed PU spheroids which were subsequently encapsulated in fibrin hydrogel. The study aims to analyze adhesion properties, proliferation capacity and phenotypic characterization of these cells. Polymerase chain reaction was carried out to detect the expression of genes specifically expressed by native IVD cells. Biochemical analyses showed an increased DNA content, and a progressive enhancement of total collagen and glycosaminoglycans (GAG) was observed during cell culture. The results suggest the synthesis of an appropriate extracellular matrix as well as a stable mRNA expression of chondrogenic and/or NP specific markers. In conclusion, the data presented indicate an alternative medical approach to current treatment options of degenerated IVD tissue.

Changes in the prevalence of asthma in adults since 1966: the Busselton health study

Asthma prevalence has increased worldwide; although less so in developed countries recently. This study assessed changes in the prevalence of asthma and related symptoms in the Busselton community since 1966. Cross-sectional respiratory health surveys of Busselton adults were conducted in 1966, 1969, 1972, 1975, 1981, 1990 and 2005-2007. Logistic regression models were used to estimate prevalence rates of asthma, respiratory symptoms, smoking, airway hyperresponsiveness (AHR) and atopy and to make comparisons in 2005-2007 and previous survey years. Asthma was defined as ever having doctor-diagnosed asthma (DDA). The prevalence of DDA was around 6% from 1966 to 1975, 8% in 1981 and rose to 19% in 2005-2007. From 1981 to 2005-2007, smoking prevalence declined and obesity and atopy increased but changes in these variables explained only a small part of the increase in DDA. Wheeze and cough/phlegm increased but AHR, breathlessness and doctor-diagnosed bronchitis remained relatively stable over the same period. These observations indicate that the increase in DDA is partly explained by increased symptoms and atopy. The lack of changes in AHR and doctor-diagnosed bronchitis suggests that factors such as diagnostic transfer and increased awareness of asthma have also contributed to the rise in prevalence of DDA.

Magnetic resonance spectroscopy for measuring the biodistribution and in situ in vivo pharmacokinetics of fluorinated compounds: validation using an investigation of liver and heart disposition of tecastemizole

BACKGROUND AND OBJECTIVE

The study of biodistribution and in situ pharmacokinetics is a challenging, but sometimes very important, aspect of premarketing characterization of drugs. We aimed to develop a non-invasive fluorine magnetic resonance (MR) spectroscopic method for the absolute quantitation of a mono-fluorinated compound and of its metabolites in the heart and liver of healthy subjects for this purpose.

METHOD

We used fluorine MR spectroscopy (MRS) at 4 T (Tesla) and external standardization in an open label multiple-dose study. Twenty-three healthy adult subjects were enrolled in the study. The surface coil localized fluorine MR spectrum was monitored in the heart and liver at baseline and after oral administration of multiple doses of tecastemizole. Steady-state measurements were made at set time points that depended upon dose, and washout measurements were made only on subjects in which in vivo fluorine signal was observed.

RESULTS AND DISCUSSION

At 4 T, under the given experimental conditions, the method had a lower limit of quantitation (LLOQ) of about 2.6 microm and a limit of detection (LOD) of about 0.3 microm for solution state samples (linewidth approximately 15 Hz). The measurement reproducibility was 6.4% using a 50 microm phantom. The effect of MR operator and spectral analyst on the calculated calibration curve slope was small, with inter-rater correlation coefficients of 0.999 and 0.998 respectively. MR signal from fluorine-containing tecastemizole-related moieties was observed in situ only at day 8 in the liver of three of five subjects dosed at 270 mg/day. The average in situ concentration was estimated to be 58+/-22 microm, with an average test-retest reproducibility of 216%. Extrapolating the in vitro results to human measurements, with an approximate linewidth of 250 Hz, predicts in situ LOD and LLOQ values of approximately 6 and 44 microm respectively. However, the human study had a fluorine MRS LOD of approximately 20 microm. The decrease in sensitivity and the increase in variability of the in vivo, in situ measurements compared with the validation study most likely arose from coil placement and incomplete rephasing of the MR signal by the respiratory phase compensation method.

CONCLUSION

The measured concentrations were the lowest ever recorded for a multi-dose exogenous mono-fluorinated compound in the human liver using a validated fluorine MR quantitation method. The proposed non-invasive MR method for studying the biodistribution and in situ pharmacokinetics of mono-fluorinated compounds in the liver and heart should have broader application to the development of non-invasive biomarkers.

Calibration of a heating/cooling chamber for X-ray diffraction measurements of mechanical stress and crystallographic texture

Methods have been developed for the calibration of specimen temperature and of specimen displacement caused by the thermal expansion of the specimen holder in a heating/cooling chamber equipped with a strip or plate heater mounted on an X-ray diffractometer. For the temperature calibration two methods were proposed. One method relies on X-ray diffraction measurements of thermal lattice strains, whereas the other method is based on resistance thermometry. The method proposed for the determination of the temperature-dependent specimen displacement is based on the measurement of diffraction-line positions of the specimen employing two diffraction geometries, one being sensitive to the specimen displacement and the other being insensitive to the specimen displacement. The thermal displacement of the specimen due to thermal expansion of the specimen holder is significant and was determined as about 38 µm per 100 K.

Navigationsgestützte Arthrodese des Iliosakralgelenks

Arthrodesis of the sacroiliac joint (SI) usually requires a large surgical exposure using the lateral approach. Computer-assisted surgery based on intraoperative 3D fluoroscopy imaging can reduce the approach to stab incisions. The clinical example shows the insertion of two screws and a cylindrical bone graft to achieve an arthrodesis of the SI joint. The intraoperatively navigated placement of implants and bone graft was performed only by stab incisions.

Detection and imaging of atmospheric radio flashes from cosmic ray air showers

The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >10(20) eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within approximately 50 Mpc through interactions with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or gamma-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing.

Regulation of the voltage gated K+ channel Kv1.3 by the ubiquitin ligase Nedd4-2 and the serum and glucocorticoid inducible kinase SGK1

The stimulation of cell proliferation by insulin like growth factor IGF-1 has previously been shown to depend on activation of voltage gated K(+) channels. The signaling involved in activation of voltage gated K(+) channel Kv1.3 includes the phosphatidylinositol-3 (PI3) protein kinase, 3-phosphoinositide dependent protein kinase PDK1 and the serum and glucocorticoid inducible kinase SGK1. However, nothing is known about mechanisms mediating the stimulation of Kv1.3 by SGK1. Most recently, SGK1 has been shown to phosphorylate and thus inactivate the ubiquitin ligase Nedd4-2. The present study has been performed to explore whether the regulation of Kv1.3 involves Nedd4-2. To this end Kv1.3 has been expressed in Xenopus oocytes with or without coexpression of Nedd4-2 and/or constitutively active (S422D)SGK1. In oocytes expressing Kv1.3 but not in water injected oocytes, depolarization from a holding potential of -80 mV to +20 mV triggers rapidly inactivating currents typical for Kv1.3. Coexpression of Nedd4-2 decreases, coexpression of (S422D)SGK1 enhances the currents significantly. The effects of either Nedd4-2 or of SGK1 are abrogated by destruction of the respective catalytic subunits ((C938S)Nedd4-2 or (K127N)SGK1). Further experiments revealed that wild type SGK1 and SGK3 and to a lesser extent SGK2 are similarly effective in stimulating Kv1.3 in both, presence and absence of Nedd4-2. It is concluded that Kv1.3 is downregulated by Nedd4-2 and stimulates by SGK1, SGK2, and SGK3. The data thus disclose a novel mechanism of Kv1.3 channel regulation.

Assessment of porcine bone metabolism by dynamic

The aim of this study was to quantify regional bone blood flow and [(18)F]fluoride ion influx with [(18)F]fluoride ion PET and correlate the results with specific static and dynamic indices of bone metabolism in healthy pigs.

METHODS

During continuous ventilation (fractional concentration of oxygen in inspired gas = 0.3), dynamic PET scans 120 min in duration were obtained for 9 mini pigs after intravenous injection of 10.0 +/- 1.2 MBq (mean +/- SD) of [(18)F]fluoride ion per kilogram of body weight. Iliac crest bone biopsies were performed immediately before the PET scan to determine static and dynamic indices of bone metabolism (i.e., the mineral apposition rate) by bone histomorphometry. Kinetic rate constants describing influx (K(1)) and efflux (k(2)) of [(18)F]fluoride as well as chemisorption and incorporation of [(18)F]fluoride (k(3)) and reverse transport (k(4)) were determined for 6 vertebral bodies in each animal. Blood flow estimates (f) were derived from K(1) values corrected for the permeability-surface area product using a previously derived correction algorithm. A rate constant describing the net forward transport rate of fluoride (K(i)) and the fluoride volume flux (K(flux)) derived from a 2-tissue-compartment model was calculated and compared with the results of Patlak graphic analysis (K(pat)).

RESULTS

A significant correlation was found between mineral apposition rate and K(i) (P < 0.005), K(flux) (P < 0.01), K(pat), K(1), and f (P < 0.05). The values of f, K(i), K(flux), and K(pat) did not correlate significantly with other static or dynamic histomorphometric indices or with age, serum alkaline phosphatase, or parathyroid hormone levels. The values of f and K(i) correlated linearly (y = 0.023 + 0.32x; r(2) = 0.74; P < 0.001).

CONCLUSION

PET bone studies using [(18)F]fluoride ion provide quantitative estimates of bone blood flow and metabolic activity that correlate with histomorphometric indices of bone formation in the normal bone tissue of the mini pig. Therefore, it seem reasonable to assume that [(18)F]fluoride ion PET can reduce the number of invasive bone biopsies, thus facilitating follow-up of patients with metabolic bone diseases.

An experimental and theoretical study of the basicity of tetra-tert-butyltetrahedrane

The gas-phase basicity (GB) of tetra-tert-butyltetrahedrane (tBu4THD) was determined by FT-ICR mass spectrometry and comparison with reference compounds of known basicity. Its GB, 1035+/-10 kJ x mol(-1), makes tetra-tert-butyltetrahedrane one of the strongest bases reported so far. Ab initio calculations [B3LYP/6-31G(d) and B3LYP/6-311 + G(d,p)//6-31G(d)] have been carried out in order to compare the high experimental basicity of tBu4THD with that estimated theoretically. Both B3LYP/6-31G(d) and QCISD(T) calculations were used to determine the reaction path which connects the initial tetrahedrane-ammonium complex with the final products, protonated cyclobutadiene (CBDH+) and ammonia.

[Gainful employment and women in the 2nd half of life]

The present study analyses gender-specific risks for women in the second half of their career, especially their labour force participation rate, the degree and quality of their vocational qualification, the risk of becoming unemployed, and their transition to retirement. The analysed data show that women obviously are at higher risks to participate in the labourforce throughout their biography. Therefore, strategies to improve the working conditions of female elderly workers should not only consist of age-specific policies, but of general practices in human resource development.

Effect of Escherichia coli chaperonin GroELS on heterologously expressed human immunodeficiency virus type 1 reverse transcriptase in vivo and in vitro

The two subunits of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (HIV-1 RT), p66 and p51, were coexpressed in Escherichia coli along with the E. coli chaperonin system GroEL/GroES. Coexpression increases the yield of heterodimeric HIV-1 RT by a factor of 4 to 5 and improves the nucleic acid binding affinity of HIV-1 RT by a factor of 1.6. We have analyzed the reasons for the improvements. The total increase in yield of HIV-1 RT can be attributed to an accumulation of RT subunits in the cells (factor of about 2.8) and an increased growth of the E. coli cells (factor of about 1.4). One reason for the accumulation in the cells is an improved stability of HIV-1 RT subunits toward bacterial proteases. In vitro studies showed that the nucleic acid binding affinity of HIV-1 RT purified from cells that did not coexpress GroELS was stimulated by adding purified GroELS (approx 1.5-fold), whereas HIV-1 RT stemming from cells coexpressing GroELS was stimulated only marginally (approx 1.1-fold). The in vivo as well as the in vitro studies suggest that the chaperonin interacts with HIV-1 RT and therefore affects the folding process of HIV-1 RT.

Ring opening of 1-methylcyclopropene and cyclopropene: matrix infrared spectroscopic identification of 2-butene-1,3-diyl and propene-1,3-diyl

Triplet 2-butene-1,3-diyl (T-11) was generated on irradiation of 1-methylcyclopropene (10) in a bromine-doped xenon matrix and was characterized by means of IR spectroscopy for the first time. Experimental results suggest that triplet propene-1,3-diyl (T-3) is formed from cyclopropene (1) under similar conditions. In accordance with theoretical calculations, the experimental data indicate that the reactions 1-->3 and 10-->11 are the lowest energy ground-state pathways for the ring opening of 1 and 10, respectively.

Isomerizations between nitrosyl halides X-N=O and isonitrosyl halides X-O-N: a matrix-spectroscopic study

Irradiation of nitrosyl bromide BrNO (4) with light of the wavelength lambda = 248 nm and nitrosyl chloride CINO (6) with lambda = 193 nm in an argon matrix at 10 K leads to the corresponding isomers isonitrosyl bromide BrON (5) and isonitrosyl chloride CION (7). Both new compounds 5 and 7 have been identified by comparison of the experimental and calculated (BLYP/6-311 + G*) IR spectra. Nitrosyl fluoride FNO (8) could not be transferred into isonitrosyl fluoride FON (9). The back reactions 5-->4 and 7-->6 can be initiated by UV (lambda > 310 nm), visible or IR light. The retransformation also occurs spontaneously in the matrix at 10 K under exclusion of any UV/Vis or IR radiation. Surprisingly, the reaction rates of these spontaneous back reactions are temperature independent between 8.5 and 25 K. The mechanism of these processes is discussed.

Optical implementation of asynchronous-transfer-mode header-error control

The asynchronous transfer mode (ATM) is a promising technique for broadband switching that is capable of supporting high-bit-rate multimedia services. Progress in all-optical parallel processing shows that photonics may be used in the future in full-functionality ATM switching nodes. All-optical switching fabrics and buffers have already been demonstrated. Fewer studies have been dedicated to ATM header-processing functions. As an example of photonic header processing, the implementation of a header-error control (HEC) subsystem by means of an optical circuit is investigated. Although traditional electronic decoders perform HEC in a serial mode, the architecture chosen for the optical HEC subsystem is based on parallelism, and an appropriate parallel-decoding algorithm was used in designing it.

Antitumor activity and induction of apoptosis by water-soluble derivatives of 7 beta-hydroxycholesterol in human colon carcinoma cell lines

At present, cancer therapy of solid tumors, such as lung and colorectal cancer, is unsatisfactory. Recently, oxygenated sterols have shown selective cytotoxicity against tumor cells. In this study, the cytotoxicity of 7 beta-hydroxycholesterol (7 beta HC) and two water-soluble derivatives of 7 beta HC, i.e. 7 beta HC-bis-hemisuccinate [disodium salt] (7 beta HC-HS) and 7 beta HC-bis-hemisuccinate-diethanolaminoate (7 beta HC-EA), was determined in DLD-1, KM20L2, HCT-116, HT-29 and SW620 colon carcinoma cell lines using a cell count assay. IC50 values of the two water-soluble derivatives were, on the whole, comparable to 7 beta HC lying in the range of 3-10 microM. In addition, the water-soluble derivatives were able to induce apoptosis in the examined DLD-1 and KM20L2 colon carcinoma cell lines in contrast to the parent compound 7 beta HC, as shown by DNA fragmentation, by the cleavage of DNA repair enzyme poly(ADP) ribose polymerase (PARP), and by the proteolytic cleavage of caspase-3 (CPP32). Due to the improved water-solubility of 7 beta HC-HS and 7 beta HC-EA and their promising antitumor activity in vitro, animal studies in suitable tumor models are warranted.

Temporal coordination between initiation of HIV (+)-strand DNA synthesis and primer removal

In this study, we have analyzed the interdependence between the polymerase and RNase H active sites of human immunodeficiency virus-1 reverse transcriptase (RT) using an in vitro system that closely mimics the initiation of (+)-strand DNA synthesis. Time course experiments show that RT pauses after addition of the 12th DNA residue, and at this stage the RNase H activity starts to cleave the RNA primer from newly synthesized DNA. Comparison of cleavage profiles obtained with 3'- and 5'-end-labeled primer strands indicates that RT now translocates in the opposite direction, i.e. in the 5' direction of the RNA strand. DNA synthesis resumes again in the 3' direction, after the RNA-DNA junction was efficiently cleaved. Moreover, we further characterized complexes generated before, during, and after position +12, by treating these with Fe2+ to localize the RNase H active site on the DNA template. Initially, when RT binds the RNA/DNA substrate, oxidative strand breaks were seen at a distance of 18 base pairs upstream from the primer terminus, whereas 17 base pairs were observed at later stages when the enzyme binds more and more DNA/DNA. These data show that the initiation of (+)-strand synthesis is accompanied by a conformational change of the polymerase-competent complex.

Mixed reconstitution of mutated subunits of HIV-1 reverse transcriptase coexpressed in Escherichia coli - two tags tie it up

The active form of HIV-1 reverse transcriptase (RT) is a p66/p51 heterodimer, in which the p51 subunit is generated by C-terminal proteolytic cleavage of p66. A well-known problem of p66 recombinant expression is partial cleavage of a 15-kDa peptide from the C-terminus by host proteases that can not be completely suppressed. In order to analyse the contribution of specific residues to a particular function in one distinct subunit, an expression and purification system is required that selects for the combination of the two individual subunits with the desired substitutions. We reconstituted the p66/p51 heterodimer from subunits coexpressed in Escherichia coli as an N-terminal fusion protein of glutathione S-transferase (GST) with p51 and a C-terminally His-tagged p66, respectively. The two-plasmid coexpression system ensures convenience for gene manipulation while degradation is reduced to a minimum, as dimerization protects the protein from further proteolysis. The combination of glutathione-agarose, phenyl-superose and Ni/nitrilotriacetate affinity chromatography allows rapid and selective purification of the desired subunit combination. Truncated forms of p51 are efficiently removed. Mobility-shift assay revealed that the preparations are free of p66 homodimer. In a successful test of the novel expression system, mixed reconstituted RTs with p51 selectively mutated in a putative nucleic acid binding motif (the so called helix clamp) show reduced binding of dsDNA in mobility-shift assays. This indicates the p51 subunit has an active role in DNA binding

Poroelastic finite element analysis of a bone specimen under cyclic loading

It had been suggested that the fluid embodied in bone lacunar-canalicular porosity may play an important role in bone remodelling [Weinbaum et al., 1994. Journal of Biomechanics 27, 339-360]. In this paper a finite element model of a poroelastic prismatic solid of rectangular cross-section is considered to simulate bone behaviour, precisely as in the previous work by Zhang and Cowin [Zhang and Cowin, 1994. Journal of Mechanical Physics of Solids 42, 1575-1599]. This solid is subject to combined cyclic axial and bending loads at its end. The objectives of the study are: (1) to verify the accuracy of the simplifying hypotheses underlying the analytical solutions established by the above authors; (2) to provide further insight into the behaviour of that solid; (3) to test the advantages in generality and versatility and the computing costs of general-purpose finite element codes in poroelastic analysis. The study is parametric with respect to the fluid leakage coefficient, to the ratio of the bending moment and axial load, and to the ratio of the characteristic relaxation time of the pore pressure over the excitation period. Results show that, for all the cases considered, the pore pressure distribution along the section height of the poroelastic beam exhibits a very good matching with previous analytical results. Stresses transversal with respect to the beam axis (assumed as constant or zero in previous analytical solutions) are evaluated. The analysis pointed out that: (1) the effects due to end-loads with zero resultants practically extinguish within a distance from the beam end almost equal to a typical length of the cross-section; (2) cross-sections remain plane above that distance; (3) the transversal total stresses are three orders of magnitude lower than axial stress.

Stimulation of phospholipase C-beta2 by the Rho GTPases Cdc42Hs and Rac1

Neutrophils contain a soluble guanine-nucleotidebinding protein, made up of two components with molecular masses of 23 and 26 kDa, that mediates stimulation of phospholipase C-beta2 (PLCbeta2). We have identified the two components of the stimulatory heterodimer by amino acid sequencing as a Rho GTPase and the Rho guanine nucleotide dissociation inhibitor LyGDI. Using recombinant Rho GTPases and LyGDI, we demonstrate that PLCbeta2 is stimulated by guanosine 5'-O-(3-thiotriphosphate) (GTP[S])-activated Cdc42HsxLyGDI, but not by RhoAxLyGDI. Stimulation of PLCbeta2, which was also observed for GTP[S]-activated recombinant Rac1, was independent of LyGDI, but required C-terminal processing of Cdc42Hs/Rac1. Cdc42Hs/Rac1 also stimulated PLCbeta2 in a system made up of purified recombinant proteins, suggesting that this function is mediated by direct protein-protein interaction. The Cdc42Hs mutants F37A and Y40C failed to stimulate PLCbeta2, indicating that the Cdc42Hs effector site is involved in this interaction. The results identify PLCbeta2 as a novel effector of the Rho GTPases Cdc42Hs and Rac1, and as the first mammalian effector directly regulated by both heterotrimeric and low-molecular-mass GTP-binding proteins.

[Clinical examinations of gilts with puerperal septicemia and toxemia]

In a clinical examination on 78 gilts suffering from feverish puerperal illness the signs were documented. 42 gilts without puerperal disturbances out of the same farms (n = 22) were used as a control. Data for statistics were recorded in minute-books, listing 38 parameters, partly divided in three or four subunits. Within the first 24 hours after parturition 60% of the probands were registered, the other gilts up to the 72nd hour after parturition. 42.3% of the patients beared for the first or second time. Duration of partus averaged more than six hours in 85.9% of patients with consequent puerperal illness, whereas probands of the same age in the control group finished parturition in less than three hours (78.8%; p < or = 0.01). Frequency of obstetrical intervention measured 27% in the group of patients, in the group of probands 9.5% (p < or = 0.05). Gilts with following puerperal illness delivered 1.1 piglets more than healthy individuals (p < or = 0.05) and showed an increased stillbirth rate (p < or = 0.01). Signs of clinical interest in puerperal illness were increase of body temperature (p < or = 0.01), cardiac rate (p < or = 0.01) and respiratory frequency (p < or = 0.01). Approximately 75% of the patients showed anorexia, 66% abnormal faecal consistency. 24.4% of the diseased animals showed exclusively signs of mastitis, in 29.5% there was a combination of mastitis and inflammatory affection of the genital system to be diagnosed, in 46.1% of the cases a solitary infection of the reproductive tract was to be stated. Predominantly E. coli, followed by Staphylococcus spp. and Streptococcus spp. were isolated from the genital tract. The results of this study emphasize the clinical necessity to differentiate between isolated mastitis and puerperal septicaemia respectively toxaemia in cases of feverish puerperal illness. Puerperal septicaemia and toxaemia can, but do not have to be associated with mastitis in gilts.

Crystal structure of an eight-base pair duplex containing the 3'-DNA-RNA-5' junction formed during initiation of minus-strand synthesis of HIV replication

During initiation of minus-strand synthesis by HIV-1 reverse transcriptase, a 3'-DNA-RNA-5' junction is formed involving the 3'-end of tRNAlys,3. The HIV-RT-associated RNase H cleaves the RNA template strand specifically, opposite the newly synthesized DNA strand. We have determined the crystal structure at 1.9 A resolution of an eight-base pair hybrid duplex representing the junction to identify global or local structural perturbations which may be recognized by HIV-RT RNase H. The junction octamer is in a global A-type conformation throughout. A base pair step with distinct stacking geometry and variable backbone conformation is located next to the main endonucleolytic cleavage site. This base pair step may serve as a recognition site for HIV-RT RNase H.

Blood flow measurements with [(15)O]H2O and [18F]fluoride ion PET in porcine vertebrae

A dual positron emission tomography (PET) tracer study with [18F]fluoride and the freely diffusible tracer [(15)O]H2O was performed to measure the capillary transport of [18F]fluoride and to evaluate the potential of [18F]fluoride ion PET to quantitate bone blood flow. Under the condition of a high predictable single-pass extraction fraction (E(F)) for [18F]fluoride, the [18F]fluoride ion influx transport constant (K1F), derived from kinetic [18F]fluoride ion PET measurements, can be used to estimate bone blood flow. Bone blood flow was measured in vertebral bodies by dynamic [(15)O]H2O PET during continuous ventilation with N2O, O2, and Isoflurane (FiO2 = 0.3) in seven adult mini pigs, followed by dynamic [18F]fluoride ion PET. The mean blood flow measured by [(15)O]H2O (FlowH2O) was 0.145 +/- 0.047 ml x minute(-1) x ml(-1) and the mean K1F was 0.118 +/- 0.031 ml x minute(-1) x ml(-1), respectively (mean +/- SD). Regional analysis showed excellent agreement between FlowH2O and K1F at low flow and a significant underestimation of flow by K1F relative to FlowH2O in regions of normal and elevated flow. The observed relationship between parameters followed the Renkin-Crone distribution. The permeability-surface product was determined as 0.25 minute(-1) for vertebral bodies consisting of a mixture of trabecular and cortical bone. We conclude that [18F]fluoride ion PET can be used to estimate bone blood flow in low and normal flow regions, as long as the flow dependency of the E(F) is taken into consideration. Above blood flow values of 0.2 to 0.35 ml x minute(-1) x ml(-1), the magnitude of K1F is increasingly independent on blood flow because diffusion limits tracer transport.

Synthesis and in vitro efficacy of transferrin conjugates of the anticancer drug chlorambucil

One strategy for improving the selectivity and toxicity profile of antitumor agents is to design drug carrier systems employing soluble macromolecules or carrier proteins. Thus, five maleimide derivatives of chlorambucil were bound to thiolated human serum transferrin which differ in the stability of the chemical link between drug and spacer. The maleimide ester derivatives 1 and 2 were prepared by reacting 2-hydroxyethylmaleimide or 3-maleimidophenol with the carboxyl group of chlorambucil, and the carboxylic hydrazone derivatives 5-7 were obtained through reaction of 2-maleimidoacetaldehyde, 3-maleimidoacetophenone, or 3-maleimidobenzaldehyde with the carboxylic acid hydrazide derivative of chlorambucil. The alkylating activity of transferrin-bound chlorambucil was determined with the aid of 4-(4-nitrobenzyl)pyridine (NBP) demonstrating that on average 3 equivalents were protein-bound. Evaluation of the cytotoxicity of free chlorambucil and the respective transferrin conjugates in the MCF7 mammary carcinoma and MOLT4 leukemia cell line employing a propidium iodide fluorescence assay demonstrated that the conjugates in which chlorambucil was bound to transferrin through non-acid-sensitive linkers, i.e., an ester or benzaldehyde carboxylic hydrazone bond, were not, on the whole, as active as chlorambucil. In contrast, the two conjugates in which chlorambucil was bound to transferrin through acid-sensitive carboxylic hydrazone bonds were as active as or more active than chlorambucil in both cell lines. Especially, the conjugate in which chlorambucil was bound to transferrin through an acetaldehyde carboxylic hydrazone bond exhibited IC50 values which were approximately 3-18-fold lower than those of chlorambucil. Preliminary toxicity studies in mice showed that this conjugate can be administered at higher doses in comparison to unbound chlorambucil. The structure-activity relationships of the transferrin conjugates are discussed with respect to their pH-dependent acid sensitivity, their serum stability, and their cytotoxicity.

Localization of the active site of HIV-1 reverse transcriptase-associated RNase H domain on a DNA template using site-specific generated hydroxyl radicals

Reverse transcriptase (RT)-associated ribonuclease H (RNase H) can cleave both the RNA template of DNA/RNA hybrids as well as double-stranded (ds) RNA. This report shows that human immunodeficiency virus (HIV)-RT can also cleave the template strand of dsDNA when Mg2+ is replaced by Fe2+ in the RNase H active site of HIV-RT. The cleavage mechanisms as well as the positions of the cut vary depending on whether RNA or DNA is used. While DNA is cleaved 17 base positions upstream of the primer 3'-end, RNA is cleaved 18 base positions upstream. Competition experiments show that Fe2+ replaces the catalytically active Mg2+ of RT-associated RNase H. The bound Fe2+ is the source of locally generated OH-radicals that cleave the most proximate base in the DNA. Electrophoretic mobility studies of the cleaved fragments suggest that DNA is cleaved by an oxidative mechanism, while RNA is cleaved by an enzymatic mechanism which is indistinguishable from the Mg2+-dependent cleavage. The Fe2+-dependent cuts can be used to trace the active site of RT-associated RNase H on dsDNA as well as on dsRNA and DNA/RNA hybrids. The observed 1 base difference in the cleavage positions on DNA and RNA templates can be attributed to conformational differences of the bound nucleic acids. We suggest that the lower pitch of dsRNA and DNA/RNA hybrids compared with dsDNA permits accommodation of an additional base pair in the region between the primer 3'-end and the Fe2+-dependent cleavage position at the RNase H active site.