Experimental check of the Gerasimov-Drell-Hearn sum rule for 1H

For the first time we checked the fundamental Gerasimov-Drell-Hearn (GDH) sum rule for the proton experimentally in the photon energy range from 0.2-2.9 GeV with the tagged photon facilities at MAMI (Mainz) and ELSA (Bonn). New data of the doubly polarized total cross section difference are presented in the energy range from 1.6 to 2.9 GeV. The contribution to the GDH integral from 0.2-2.9 GeV yields [254+/-5(stat)+/-12(syst)] microb with negative contributions in the Regge regime at photon energies above 2.1 GeV. This trend supports the validity of the GDH sum rule.

Spontaneous and genetically engineered animal models; use in preclinical cancer drug development

The preclinical development of anticancer drugs has been based primarily on the transplantation of murine or human cancers into mice. Alternatives to these transplantation models are animals that naturally develop cancers with features relevant to the human disease. The first group of these models arises in mice that are genetically engineered to develop cancer. The second group includes pet dogs and cats that naturally develop cancer. This review will discuss the use and integration of these spontaneous cancer models into a comprehensive and comparative approach to preclinical drug development. Examples of their successful use and an outline of their relative strengths and weaknesses will be provided.

Measurement of anomalous dispersion in microstructured fibers using spectral modulation

We report on a simple technique to measure the anomalous dispersion of small-core microstructured fibers using short optical pulses. The method relies on the spectral modulation resulting from the evolution of the input pulse into a propagating soliton wave. The technique allows for a direct measurement of the dispersion at the desired wavelength from a single pulse. The measurement error is estimated to be less than 10%.

Energy distributions in multiple photon absorption experiments

Photofragmentation experiments on molecules and clusters often involve multiple photon absorption. The distributions of the absorbed number of photons are frequently approximated by Poisson distributions. For realistic laser beam profiles, this approximation fails seriously due to the spatial variation of the mean number of absorbed photons across the laser beam. We calculate the distribution of absorbed energy for various laser and molecular-beam parameters. For a Gaussian laser beam, the spatially averaged distributions have a power-law behavior for low energy with a cutoff at an energy which is proportional to fluence. The power varies between -1 for an almost parallel laser beam and -5/2 for a divergent beam (on the scale of the molecular beam). We show that the experimental abundance spectra of fullerenes and small carbon clusters can be used to reconstruct the distribution of internal energy in the excited C60 molecule prior to fragmentation and find good agreement with the calculated curves.

First Measurement of the Gerasimov-Drell-Hearn Sum Rule for 1H from 0.7 to 1.8 GeV at ELSA

To verify the fundamental Gerasimov-Drell-Hearn (GDH) sum rule for the first time experimentally, we measured the helicity dependent total photoabsorption cross section with circularly polarized real photons and longitudinally polarized nucleons in the photon energy range 0.68-1.82 GeV with the tagged photon facility at ELSA. The experiment was carried out with a 4pi detection system, a circularly polarized tagged photon beam, and a frozen spin polarized proton target. The contribution to the GDH sum rule in this photon energy range is [49.9+/-2.4(stat)+/-2.2(syst)] microb.

All-fiber chirped pulse amplification using highly-dispersive air-core photonic bandgap fiber

We show, for the first time to our knowledge, all-fiber chirped pulse amplification using an air-core photonic bandgap fiber. Pulses from a wavelength- and duration-tunable femtosecond/picosecond source at 10 GHz were dispersed in 100 m of dispersion compensating fiber before being amplified in an erbium-doped fiber amplifier and subsequently recompressed in 10 m of the anomalously dispersive photonic bandgap fiber. Pulses as short as 1.1 ps were obtained. As air-core fibers present negligible nonlinearity, the presented configuration can potentially be used to obtain ultra-high pulse peak powers. A study of the air-core fiber dispersion and dispersion slope is also presented.

Photoneutron yields from tungsten in the energy range of the giant dipole resonance

Photoneutron production on the nuclei of high-Z components of medical accelerator heads can lead to a significant secondary dose during a course of bremsstrahlung radiotherapy. However, a quantitative evaluation of secondary neutron dose requires improved data on the photoreaction yields. These have been measured as a function of photon energy, neutron energy and neutron angle for natW, using tagged photons at the MAX-Lab photonuclear facility in Sweden. This work presents neutron yields for natW(gamma, n) and compares these with the predictions of the Monte Carlo code MCNP-GN, developed specifically to simulate photoneutron production at medical accelerators.

Dispersion flattened hybrid-core nonlinear photonic crystal fiber

Photonic crystal fibers are highly attractive as nonlinear media as they combine a large nonlinear coefficient and a highly ustomizable zero dispersion wavelength - flexibility not found in any other medium. However, the high dispersion slope at the zero-dispersion wavelength demonstrated so far is very limiting to the useful bandwidth. We propose a new fiber design comprising a hybrid core-region with three-fold symmetry that enables unprecedented dispersion control while maintaining low loss and a high nonlinear coefficient. The lowest dispersion slope obtained is 1.10-3ps/(km.nm2) or one order of magnitude lower than for conventional slope reduced nonlinear fibers. The nonlinear coefficient is more than 11 (W.km)-1 and loss below 7.9 dB/km at 1.55 microm has been achieved.

Compton scattering from the deuteron and extracted neutron polarizabilities

Differential cross sections for Compton scattering from the deuteron were measured at MAX-Lab for incident photon energies of 55 and 66 MeV at nominal laboratory angles of 45 degrees, 125 degrees, and 135 degrees. Tagged photons were scattered from liquid deuterium and detected in three NaI spectrometers. By comparing the data with theoretical calculations in the framework of a one-boson-exchange potential model, the sum and the difference of the isospin-averaged nucleon polarizabilities, alpha(N)+beta(N)=17.4+/-3.7 and alpha(N)-beta(N)=6.4+/-2.4 (in units of 10(-4) fm(3)), have been determined. By combining the latter with the global-averaged value for alpha(p)-beta(p) and using the predictions of the Baldin sum rule for the sum of the nucleon polarizabilities, we have obtained values for the neutron electric and magnetic polarizabilities of alpha(n)=8.8+/-2.4(total)+/-3.0(model) and beta(n)=6.5-/+2.4(total)-/+3.0(model), respectively.

A pharmacoeconomic evaluation of escitalopram, a new selective serotonin reuptake inhibitor. Comparison of cost-effectiveness between escitalopram, citalopram, fluoxetine, and venlafaxine for the treatment of depression in Norway

This study compared the cost-effectiveness of escitalopram to that of citalopram,fluoxetine, and venlafaxine in the treatment of depression in Norway. A two-path decision analytic model with a 6-month horizon was used. Patients start at the primary path and are referred to specialist care in the secondary care path. Model inputs included drug-specific probabilities from comparative trial data, literature, and a panel of experts. The main outcome measure is success (remission), and costs of treatment (total and drug costs). Treatment with escitalopram yielded lower expected cost and greater effectiveness than citalopram, fluoxetine, and venlafaxine. The expected success rate was 64.2% with escitalopram,58.7% with citalopram, 58.7% with fluoxetine, and 62.1% with venlafaxine. Average expected total costs per patient were similar with escitalopram (19,661 Norwegian crowns) and venlafaxine (20,989) and somewhat higher with citalopram (22,379) and fluoxetine (22,558). Budgetary impact estimates a decrease in total health care budget of 72 million crowns. Escitalopram is therefore the most cost-effective alternative and its use would significantly reduce health care costs for the treatment of depression in Norway.

Current-voltage curves of atomic-sized transition metal contacts: an explanation of why Au is Ohmic and Pt is not

We present an experimental study of current-voltage (I-V) curves on atomic-sized Au and Pt contacts formed under cryogenic vacuum (4.2 K). Whereas I-V curves for Au are almost Ohmic, the conductance G=I/V for Pt decreases with increasing voltage, resulting in distinct nonlinear I-V behavior. The experimental results are compared with first principles density functional theory calculations for Au and Pt, and good agreement is found. The difference in conductance properties for Pt vs Au can be explained by the underlying electron valence structure: Pt has an open d shell while Au has not.

Helicity amplitudes A1/2 and A3/2 for the D13(1520) resonance obtained from the gamma-->p-->-->ppi(0) Reaction

The helicity dependence of the gamma-->p-->-->ppi(0) reaction has been measured for the first time in the photon-energy range from 550 to 790 MeV. The experiment, performed at the Mainz microtron MAMI, used a 4pi-detector system, a circularly polarized, tagged photon beam, and a longitudinally polarized frozen-spin target. These data are predominantly sensitive to the D13(1520) resonance and are used to determine its helicity amplitudes.

Dependence of morphology on agitation intensity in fed-batch cultures of Aspergillus oryzae and its implications for recombinant protein production

We previously reported that, although agitation conditions strongly affected mycelial morphology, such changes did not lead to different levels of recombinant protein production in chemostat cultures of Aspergillus oryzae (Amanullah et al., 1999). To extend this finding to another set of operating conditions, fed-batch fermentations of A. oryzae were conducted at biomass concentrations up to 34 g dry cell weight/L and three agitation speeds (525, 675, and 825 rpm) to give specific power inputs between 1 and 5 kWm(-3). Gas blending was used to control the dissolved oxygen level at 50% of air saturation except at the lowest speed where it fell below 40% after 60-65 h. The effects of agitation intensity on growth, mycelial morphology, hyphal tip activity, and recombinant protein (amyloglucosidase) production in fed-batch cultures were investigated. In the batch phase of the fermentations, biomass concentration, and AMG secretion increased with increasing agitation intensity. If in a run, dissolved oxygen fell below approximately 40% because of inadequate oxygen transfer associated with enhanced viscosity, AMG production ceased. As with the chemostat cultures, even though mycelial morphology was significantly affected by changes in agitation intensity, enzyme titers (AGU/L) under conditions of substrate limited growth and controlled dissolved oxygen of >50% did not follow these changes. Although the measurement of active tips within mycelial clumps was not considered, a dependency of the specific AMG productivity (AGU/g biomass/h) on the percentage of extending tips was found, suggesting that protein secretion may be a bottle-neck in this strain during fed-batch fermentations.

Pyogranulomatous myocarditis due to Staphylococcus aureus septicaemia in two harbour porpoises (Phocoena phocoena)

Staphylococcus aureus septicaemia was diagnosed in a dead, stranded harbour porpoise from the German Baltic Sea and in a live harbour porpoise by-caught in inner Danish waters and taken into captivity. Lesions included pyogranulomatous myocarditis, necrotising suppurative bronchopneumonia, pyelonephritis, osteomyelitis and leptomeningitis, and abscesses in lymph nodes and skeletal muscles. The captive animal had fibrinous suppurative epicarditis and pyogranulomatous myocarditis with abscesses. In both animals the organism was suspected to have entered through skin lesions or via the respiratory tract.

A pharmacoeconomic evaluation of zuclopenthixol compared with haloperidol and risperidone in the treatment of schizophrenia

Zuclopenthixol and haloperidol are antipsychotic medications displaying different galenic forms, while risperidone is available on the market only in tablet form. The depot form presents advantages; the duration of action allows 3-4 weeks between administrations. A meta-analysis showed that zuclopenthixol patients had a higher response rate than haloperidol. A Markov model was developed to estimate the cost-effectiveness of the three antipsychotics in schizophrenia over a 5-year period. Model parameter estimates were based on a meta-analysis and literature. The viewpoint was that of the French National Health Insurance. When compared to haloperidol and risperidone, zuclopenthixol patients had additional 4 and 7 months without relapse correspondingly over a 5-year period. The estimated 5-year medical cost associated with zuclopenthixol was 800 and 1100 euros less than haloperidol and risperidone, respectively, per patient. Sensitivity analyses indicated that the results were robust to changes in key variables. The model indicates that the zuclopenthixol treatment strategy dominates haloperidol and risperidone.

Observation of a 1/t decay law for hot clusters and molecules in a storage ring

The exponential law is valid both for decay from a single quantum state into a continuum and for an ensemble maintained in thermal equilibrium. For statistical decay of an ensemble of isolated systems with a broad energy distribution, the exponential decay is replaced by a 1/t distribution. We present confirmation of this decay law by experiments with cluster anions in a small electrostatic storage ring. Deviations from the 1/t law for such an ensemble give important information on the dynamics of the systems. As examples, we present measurements revealing strong radiative cooling of anions of both metal clusters and fullerenes.

Hsal 1 is related to kidney and gonad development and is expressed in Wilms tumor

Townes-Brocks syndrome (TBS) is a human genetic disorder with features including urogenital, limb, anal and cardiac malformations associated with mutations of the TBS gene, Hsal 1. To begin to understand the role of the Hsal 1 protein (p140) in both normal development and disease pathogenesis, both message and protein expression were evaluated in specific tissues associated with TBS. DNA sequence information for Hsal 1 predicts that this homeotic, Drosophila homologue (Sal) encodes a zinc-finger protein consistent with a transcription factor. mRNA for Hsal 1 was highly expressed in fetal kidney and brain, with detectable production in thymus and heart. p140 was found in fetal ureteric bud, fetal and postnatal renal tubular epithelium, and renal blastema. In the 14-week fetal testis, the Hsal 1 protein was specifically expressed in the testosterone producing Leydig cells while in adult gonads Hsal 1 was also found in both Leydig and Sertoli cells, spermatogonia of the testis, and granulosa cells of the ovary. Evaluation of Wilms tumor revealed consistently high expression of the gene product in the epithelial and blastemal components. These spatial and temporal patterns of expression for Hsal 1, and the phenotypic effects associated with TBS, suggest that Hsal 1 plays an important role in the development and functional maintenance of the kidney and gonads. Furthermore, the Hsal 1 gene product may play a part in the pathogenesis of specific neoplasms occurring in these organs in addition to its specific role in Townes-Brocks syndrome.

Model-free determination of dissociation energies of polyatomic systems

We describe and apply a new procedure that allows a direct determination of dissociation energies of polyatomic systems (clusters, fullerenes, polymers, and other molecules) without any modeling of the systems under investigation. As an example, we have determined the dissociation energies of a series of gold clusters Au(+)n. A comparison with values obtained from statistical models of unimolecular dissociation shows that these models significantly fail to describe the data. In contrast, the new method yields values which are an order of magnitude more accurate, thus allowing one to experimentally set benchmarks for any theory which attempts to describe activated processes.

Outpatient laparoscopic cholecystectomy. A prospective study with 100 consecutive patients

One hundred patients with cholelithiasis were included in a prospective consecutive follow-up study to evaluate laparoscopic cholecystectomy in a day surgical setting. The median operating time was 70 min. In 96% of the patients, it was possible to perform peroperative cholangiography. The median time off work was 7 days and the median time to full recovery was 14 days. Five patients were admitted due to weakness/nausea. Six patients were admitted due to conversion to open surgery or choledocholithiasis. Eighty-nine patients were treated in ambulatory surgery. We conclude that laparoscopic outpatient cholecystectomy can be performed safely with a low unplanned admission rate.

A prospective evaluation of the clinical presentation of pediatric pelvic fractures

BACKGROUND

We sought to describe pediatric, blunt trauma patients with pelvic fracture (PF) and to evaluate pelvis examination sensitivity and specificity.

METHODS

We conducted a prospective study of blunt trauma patients at a Level I pediatric trauma center. A pediatric emergency medicine physician attempted to diagnose a PF, solely on the basis of the history and pelvis examination. Patients with blunt trauma but no pelvic fracture (NPF) were used as controls.

RESULTS

We enrolled 140 patients (16 PF, 124 NPF), and no significant differences were found regarding median age, gender, injury mechanism, acuity, and medical outcome. Approximately 25% of PF patients had iliac-wing fractures; 37%, single pelvic ring; 25%, double pelvic ring; and 13%, acetabular fractures. Eleven patients with PF had an abnormal pelvis examination (69% sensitivity), compared with six NPF patients (95% specificity, negative predictive value 0.91).

CONCLUSION

Pediatric patients with PF have low mortality and few complex fractures. The pelvis examination appears to have both high specificity and negative predictive value.

Asplenic-hyposplenic overwhelming sepsis: postsplenectomy sepsis revisited

Absence of the spleen or splenic function predisposes individuals to risk of overwhelming infection. These infections are most often due to encapsulated organisms, especially pneumococcus, Haemophilus influenzae type b, and meningococcus, but any bacterial agent may cause the rapid onset of septicemia, meningitis, pneumonia, and shock characteristic of the asplenic-hyposplenic condition. The risk is greatest in infants and young children, but asplenic-hyposplenic adults also have an increased risk of infection. Prophylactic antibiotics and immunization with polyvalent pneumococcal, H. influenzae type b, and meningococcal vaccines have reduced the incidence of infections in asplenic-hyposplenic individuals, but even these measures have not eliminated the risk. Surgeons have adopted techniques to save as much splenic tissue as possible and some splenic functions, such as pitting red cells, have been preserved, but conservative surgery has not provided total protection against overwhelming infection. Therapies designed to interrupt the cascade of overwhelming sepsis have not yet been successful. In those cases in which the spleen is surgically removed, the underlying disease or condition leading to splenectomy influences the risk of sepsis. Splenectomy incidental to other operations, such as gastrectomy, results in the lowest risk for overwhelming infection, but this is still some 35-fold greater than the risk for overwhelming infections in the general population. In increasing order of risk, the other main indications for surgical removal of the spleen are idiopathic thrombocytopenia purpura, trauma, transplantation procedures, hereditary spherocytosis, staging Hodgkin's disease, portal hypertension with hypersplenism, and thalassemia. Pathologists should comment on the risk of overwhelming sepsis when spleens are processed as surgical specimens, and should carefully weigh all splenic tissue, including accessory spleens and splenic implants (splenosis), in autopsy cases with and without overwhelming sepsis.

Determination of drug effect on tumour cells, host animal toxicity and drug pharmacokinetics in a hollow-fibre model in rats

PURPOSE

Based on the previously published hollow-fibre assay mainly used for early in vivo anticancer drug screening, we wanted to develop an extended hollow-fibre model in which antitumour activity, haematological toxicity and pharmacokinetics could be studied in the same animal.

METHOD

The breast cancer cell lines MDA-MB-231 and MCF-7 were cultured in semipermeable hollow fibres. The fibres were implanted subcutaneously into immunocompetent male Sprague Dawley rats, and the rats were treated with 5-fluorouracil (5-FU, 125 mg/kg), epirubicin (EPI, 10 mg/kg) or cyclophosphamide (CP, 120 mg/kg) intraperitoneally, the new cyanoguanidine CHS 828 (375 mg/kg or 75 mg/kg x 5) orally, or vehicle only. After 6 days the fibres were retrieved and the cell density was evaluated. Haematological parameters were monitored and two to four samples per animal were drawn to determine the pharmacokinetic parameters in NONMEM.

RESULTS

Drug treatment had generally low effects on the tumour cells. Of the standard drugs (5-FU, EPI and CP), only CP exerted a statistically significant antiproliferative effect. CHS 828 had only a minor effect as a single dose, but divided into five daily doses had a pronounced effect on both cell lines. 5-FU, EPI and CP all caused a marked decrease in leucocytes, platelets and haemoglobin, while CHS 828 did not seem to affect these parameters. The pharmacokinetics of 5-FU and EPI were in accordance with previously established pharmacokinetic models. The pharmacokinetics of CP and CHS 828 were both described by one-compartment models.

CONCLUSIONS

This study illustrates the possibility of measuring antitumour effect, haematological toxicity and pharmacokinetics in the same animal using the hollow-fibre model.

Origin of nanomechanical cantilever motion generated from biomolecular interactions

Generation of nanomechanical cantilever motion from biomolecular interactions can have wide applications, ranging from high-throughput biomolecular detection to bioactuation. Although it has been suggested that such motion is caused by changes in surface stress of a cantilever beam, the origin of the surface-stress change has so far not been elucidated. By using DNA hybridization experiments, we show that the origin of motion lies in the interplay between changes in configurational entropy and intermolecular energetics induced by specific biomolecular interactions. By controlling entropy change during DNA hybridization, the direction of cantilever motion can be manipulated. These thermodynamic principles were also used to explain the origin of motion generated from protein-ligand binding.

The costs of HIV/AIDS care at government hospitals in Zimbabwe

According to official figures, HIV infection in Zimbabwe stood at 700 000-1 000 000 in 1995, representing 7-10% of the population, with even higher expected numbers in 2000. Such high numbers will have far reaching effects on the economy and the health care sector. Information on costs of treatment and care of HIV/AIDS patients in health facilities is necessary in order to have an idea of the likely costs of the increasing number of HIV/AIDS patients. Therefore, the present study estimated the costs per in-patient day as well as per in-patient stay for patients in government health facilities in Zimbabwe with special emphasis on HIV/AIDS patients. Data collection and costing was done in seven hospitals representing various levels of the referral system. The costs per in-patient day and per in-patient stay were estimated through a combination of two methods: bottom-up costing methodology (through an in-patient note review) to identify the direct treatment and diagnostic costs such as medication, laboratory tests and X-rays, and the standard step-down costing methodology to capture all the remaining resources used such as hospital administration, meals, housekeeping, laundry, etc. The findings of the study indicate that hospital care for HIV/AIDS patients was considerably higher than for non-HIV/AIDS patients. In five of the seven hospitals visited, the average costs of an in-patient stay for an HIV/AIDS patient were found to be as much as twice as high as a non-HIV/AIDS patient. This difference could be attributed to higher direct costs per in-patient day (medication, laboratory tests and X-rays) as well as longer average lengths of stay in hospital for HIV/AIDS patients compared with non-infected patients. Therefore, the impact on hospital services of increasing number of HIV/AIDS patients will be enormous.

Differential expression of laminin chains and anti-laminin autoantibodies in experimental lupus nephritis

Mice with chronic graft-versus-host disease (GvHD) develop a lupus-like disease with severe immune complex glomerulonephritis. Previous studies with this model have shown that anti-laminin autoantibodies are involved in immune complex formation and that glomerular laminin expression alters qualitatively. The present study investigated glomerular laminin chain expression and autoantibody reactivity with matrix antigens during disease development in mice with chronic GvHD, killed before and 6, 8, 10, and 11 weeks after disease induction, using antibodies raised against laminin chain peptides, in immunofluorescence and western blotting studies. Decreased glomerular expression of the laminin beta1 chain, unaltered expression of the laminin beta2 and gamma1 chains, and increased expression of the laminin alpha1 chain and filamin/actin-binding protein 280 (ABP 280) were found during disease progression. Furthermore, 4 weeks after disease induction, autoantibodies appeared which were reactive with laminin alpha1, beta1, beta2, and gamma1 chains, and filamin in rat mesangial cell matrix. Ten weeks after disease induction, autoantibodies reacted with filamin, and beta2 and gamma1 laminin chains. Autoantibodies reacted with laminin chains only and not with other proteins in matrices extracted from glomeruli of normal and diseased mice. Staining with H50, an anti-laminin alpha1 chain/anti-filamin monoclonal autoantibody derived from an MRL/lpr mouse with spontaneous lupus nephritis, confirmed these observations and showed identical anti-laminin/anti-filamin autoantibody reactivity in two different models for lupus nephritis. In summary, differential glomerular expression of laminin chains was found during the development of chronic GvHD. Concomitantly with expression of the laminin alpha1 chain and/or filamin in the glomerulus, anti-laminin alpha1 and/or anti-filamin reactivity was present, pointing towards a role for (neo) antigen expression in the epitope spreading of the immune response. Furthermore, glomerular expression of laminin beta1 decreased in conjunction with decreased presence of anti-laminin beta1 reactivity, presumably due to antigen masking or shedding of immune complexes into the urine. These changes in anti-laminin chain autoantibodies, with concomitant alterations in the glomerular expression of laminin chains, may aggravate progressive immune injury in this model for lupus nephritis.

Long-term serological follow-up of patients treated for chronic cutaneous borreliosis or culture-positive erythema migrans

The kinetics of antibodies to Borrelia burgdorferi following successful treatment of early and late cutaneous borreliosis were analysed in consecutive serum samples by an enzyme-linked immunosorbent assay (ELISA) technique. Twenty-three patients with culture positive erythema migrans were followed for 23+/-14 months: 41% stayed seronegative, 35% showed an isolated immunoglobulin M (IgM) response, 8% an isolated IgG response and 16% a combined IgM and IgG responses. In general, antibody levels peaked within the first 3 months of symptom onset, whereafter a gradual decline was observed within 1 year. Twenty-two patients with chronic cutaneous borreliosis were followed for 23+/-11 months and all patients stayed IgG positive. Nearly three-quarters showed a clear decline in IgG levels over the years, while the rest did not. After 9+/-1 years 88% of 16 patients examined were still IgG positive. In conclusion, treatment of erythema migrans should be initiated on clinical appearance as a substantial number of patients stayed seronegative. Treatment success may in part be monitored serologically for both seropositive erythema migrans and chronic cutaneous borreliosis as most patients show declining titres after successful treatment. However, continuously high titres do not necessarily indicate treatment failure.

Class II correction in patients treated with class II elastics and with fixed functional appliances: a comparative study

The aim of the present study was to evaluate quantitatively the skeletal and dental changes contributing to Class II corrections in subjects treated with Class II elastics (Begg technique) compared with subjects treated with fixed functional appliances (Herbst appliance). Thirty-six male patients with Class II, Division 1 malocclusions whose treatment had not included extraction were investigated. Eighteen were treated with the Begg technique, and eighteen were treated with Herbst appliance for an average period of 1.3 and 0.5 years, respectively. Lateral radiographs in habitual occlusion were taken at the start of treatment and 12 months afterwards. In the Begg group, the maxilla moved forward 1 mm more than in the Herbst group, and the mandible moved 1 mm more in the Herbst group than in the Begg group. The skeletal improvement in the Herbst group exceeded the changes in the Begg group by, on average, 2.0 mm (P <.01). The overjet reduction in the Begg group was larger (2.1 mm; P <.01) than in the Herbst group, mostly because of dental movements. The skeletal part of the overjet reduction was 4% in the Begg group compared with 51% in the Herbst group. The molar correction was similar in both groups, but in the Begg group, the skeletal improvement was 10%, compared with 66% in the Herbst group. The overbite correction and the increase in the anterior lower facial height and in the NSL/ML angle were larger in the Begg group (P <.05). The conclusions of this study were that the changes contributing to the Class II corrections in Begg and Herbst therapy were skeletal and dental. The skeletal changes were, however, larger in the Herbst-treated group. On the other hand, favorable and unfavorable vertical changes were more pronounced in the group treated with Class II elastics.

Helicity dependence of gammap --> Npi below 450 MeV and contribution to the Gerasimov-Drell-Hearn sum rule

The helicity dependence of the single pion photoproduction on the proton has been measured in the energy range from 200 to 450 MeV for the first time. The experiment, performed at the Mainz microtron MAMI, used a 4pi-detector system, a circularly polarized, tagged photon beam, and a frozen-spin target. The data obtained provide new information for multipole analyses of pion photoproduction and determine the main contributions to the Gerasimov-Drell-Hearn sum rule and the forward spin polarizability gamma(0).

Diagnostic value of PCR for detection of Borrelia burgdorferi DNA in clinical specimens from patients with erythema migrans and Lyme neuroborreliosis

BACKGROUND

The aim of the study is to evaluate the diagnostic sensitivity of a 16S ribosomal RNA-based PCR on clinical specimens from patients with erythema migrans (EM) and neuroborreliosis and to compare the sensitivities with those obtained by in vitro culture and serological testing. A semiquantitative detection system, representing the input amount of specific DNA and thus the density of spirochetes in clinical specimens, indicated the preferred clinical sample to obtain for PCR testing.

METHODS AND RESULTS

Skin biopsy and urine samples from 31 patients with EM and cerebrospinal fluid (CSF) and urine samples from 30 patients with neuroborreliosis were investigated. Borrelia burgdorferi DNA was detected in 71% of the skin biopsy specimens and 13% of the urine samples from patients with EM. Forty-one percent of the patients with EM were found to have B burgdorferi-specific antibodies in serum, and B burgdorferi was cultured in 29% of the EM specimens. For patients with neuroborreliosis, the diagnostic sensitivities in CSF and urine samples were 17% and 7%, respectively. Specific intrathecal antibody production was found in 90% of the patients, and 87% showed elevated B burgdorferi antibodies in serum. In general, PCR of skin biopsy samples yielded very high amounts of amplicons versus low amounts for CSF and urine samples.

CONCLUSIONS

PCR of skin biopsy specimens is currently the most sensitive and specific test for the diagnosis of patients with EM, superior to culture and serological testing. For B burgdorferi-specific CSF disgnosis in patients with neuroborreliosis, the measurement of specific intrathecal antibody synthesis is superior to PCR. However, in patients with a short duration of disease (<14 days), PCR may be a useful diagnostic supplement. PCR of urine samples cannot be recommended at the present time for routine diagnosis of patients with EM or neuroborreliosis.

The unpredictable character of congenital cystic lung lesions

BACKGROUND

The spectrum of congenital cystic disease of the lung ranges from hydrops and neonatal respiratory distress to asymptomatic lesions. Surgical management is dictated by the presence of symptoms, recurrent infection, and the potential risk of malignant transformation.

METHODS

Since 1995, all consecutive patients with congenital cystic lung lesions underwent follow-up for symptoms, treatment, and correlation of presumptive with pathological diagnosis.

RESULTS

Twelve cystic lung lesions were identified. Seven were diagnosed with mediastinal shift in utero; in 6 of 7, the shift subsequently resolved. Overall, 6 of 7 lesions that were followed up serially decreased in size. Two patients were symptomatic in utero; 1 underwent thoracoamniotic shunting, 1 pleurocentesis for impending hydrops. Postnatally, these 2, and 2 other newborns required urgent surgery. Five of 8 asymptomatic patients had elective resection by 16 months, and 4 await operation. In 6 of the 9 surgical cases (67%), there was a discrepancy between preoperative and pathological diagnosis. There were 4 hybrid congenital cystic adenomatoid malformation (CCAM)/sequestrations.

CONCLUSIONS

At least 6 of 7 congenital cystic lung lesions decreased in size regardless of gestational age or presence of mediastinal shift. Antenatal intervention is therefore rarely indicated. Hybrid morphology may necessitate resection of stable, asymptomatic lesions to prevent the theoretical concern for associated malignancies as well as other complications of CCAM.

Distinct versus redundant properties among members of the INK4 family of cyclin-dependent kinase inhibitors

p16(INK4a), p15(INK4b), p18(INK4c) and p19(INK4d) comprise a family of cyclin-dependent kinase inhibitors and tumor suppressors. We report that the INK4 proteins share the ability to arrest cells in G1, and interact with CDK4 or CDK6 with similar avidity. In contrast, only p18 and particularly p19 are phosphorylated in vivo, and each of the human INK4 proteins shows unique expression patterns dependent on cell and tissue type, and differentiation stage. Thus, the INK4 proteins harbor redundant as well as non-overlapping properties, suggesting distinct regulatory modes, and diverse roles for the individual INK4 family members in cell cycle control, cellular differentiation, and multistep oncogenesis.

From above threshold ionization to statistical electron emission: the laser pulse-duration dependence of C60 photoelectron spectra

The photoelectron spectra of C60 ionized using a 790 nm laser with pulse durations varying from 25 fs to 5 ps have been determined. For 25 fs pulses, in the absence of fragmentation, the ionization mechanism is direct multiphoton ionization with clear observation of above threshold ionization. As the pulse duration is increased, this becomes dominated by a statistical ionization due to equilibration among the electronic degrees of freedom. For pulse durations on the order of a ps coupling to the vibrational degrees of freedom occurs and the well-known phenomenon of delayed (&mgr;s) ionization is observed.

Chemosensory control of pollen ingestion in the hoverfly Eristalis tenax by labellar taste hairs

The labellar gustatory system of the dronefly Eristalis tenax L. (Syrphidae; Diptera) that enables the fly to discriminate between pollen and nectar is investigated, and the triggering of pollen ingestion is examined. In behavioural preference tests, exhaustively extracted pollen of the sunflower Helianthus annuus is consumed in smaller amounts than untreated pollen, indicating that water-soluble substances are important for acceptance. Dry pollen is preferred over moist pollen in which the grains stick together, suggesting that mechanical properties of the pollen also play a role in its sensory assessment. Electrophysiological studies of the labellar taste hairs reveal that aqueous extracts of pollen (2% w/v) stimulate the salt receptor cell, but not the sugar receptor cell. The response of the water receptor cell remains the same as to pure water (or standard electrolyte, 10 mmol.l-1 KCl). Of the 20 amino acids tested, the salt cell is sensitive only to proline in a submillimolar range. Behavioural experiments support the electrophysiological findings. When KCl is applied at concentrations eliciting salt-cell spike frequencies equal to those produced by pollen extract (which is often accepted), the water receptor cell is inhibited and a pronounced rejection behaviour occurs. This rejection of concentrated salt solution in Eristalis is therefore mainly mediated by the inhibition of the water cell.

Effect of branch frequency in Aspergillus oryzae on protein secretion and culture viscosity

Highly branched mutants of two strains of Aspergillus oryzae (IFO4177, which produces alpha-amylase, and a transformant of IFO4177 [AMG#13], which produces heterologous glucoamylase in addition to alpha-amylase) were generated by UV or nitrous acid mutagenesis. Four mutants of the parental strain (IFO4177), which were 10 to 50% more branched than the parental strain, were studied in stirred batch culture and no differences were observed in either the amount or the rate of enzyme production. Five mutants of the transformed parental strain (AMG#13), which were 20 to 58% more branched than the parental strain, were studied in either batch, fed-batch or continuous culture. In batch culture, three of the mutants produced more glucoamylase than the transformed parental strain, although only two mutants produced more glucoamylase and alpha-amylase combined. No increase in enzyme production was observed in either chemostat or fed-batch culture. Cultures of highly branched mutants were less viscous than those of the parental and transformed parental strains. A linear relationship was found between the degree of branching (measured as hyphal growth unit length) and culture viscosity (measured as the torque exerted on the rheometer impeller) for these strains. DOT-controlled fed-batch cultures (in which the medium feed rate was determined by the DOT) were thus inoculated with either the transformed parent or highly branched mutants of the transformed parent to determine whether the reduced viscosity would improve aeration and give higher enzyme yields. The average rate of medium addition was higher for the two highly branched mutants (ca. 8.3 g medium h(-1)) than for the parental strain (5.7 g medium h(-1)). Specific enzyme production in the DOT controlled fed-batch cultures was similar for all three strains (approx. 0.24 g alpha-amylase and glucoamylase [g of biomass](-1)), but one of the highly branched mutants made more total enzyme (24.3 +/- 0.2 g alpha-amylase and glucoamylase) than the parental strain (21.7 +/- 0.4 g alpha-amylase and glucoamylase).

Inhibitors present in blood do not inhibit PCR from buccal cell preparations: case report

BACKGROUND

Hemochromatosis is a common disease that is characterized by high ferritin levels and/or high iron saturation and mutations in two alleles.

MATERIAL AND METHODS

Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) is often performed on DNA extracted from blood since blood yields high concentrations of DNA. However, inhibitors can cause PCR failure in DNA extracted from blood thus preventing a molecular diagnosis.

RESULTS

This report describes a case where multiple blood draws resulted in unamplifiable DNA. Subsequently, a buccal cell sample was collected and extracted. DNA extracted from the buccal cells yielded amplifiable DNA in contrast to DNA extracted from the patient's blood. In addition, the patient was identified as having a homozygous mutation for one allele of the hemochromatosis gene.

CONCLUSION

These results suggests that a buccal cell DNA extraction may be useful in cases where blood samples contain inhibitory substances for PCR.

Upper trapezius muscle activity patterns during repetitive manual material handling and work with with a computer mouse

Firstly, upper trapezius EMG activity patterns were recorded on the dominant side of 6 industrial production workers and on the side operating a computer mouse of 14 computer-aided design (CAD) operators to study differences in acute muscular response related to the repetitiveness of the exposure. The work tasks were performed with median arm movement frequencies ranging from 5 min(-1) to 13 min(-1) and were characterized by work cycle times ranging from less than 30 sec to several days. However, the static and median EMG levels and EMG gap frequencies were similar for all work tasks indicating that shoulder muscle loads may be unaffected by large variations in arm movement frequencies and work cycle times. An exposure variation analyses (EVA) showed that the EMG activity patterns recorded during production work were more repetitive than during CAD work, whereas CAD work was associated with more static muscle activity patterns, both may be associated with a risk of developing musculoskeletal symptoms. Secondly, upper trapezius EMG activity patterns recorded on the mouse side of the CAD operators were compared with those recorded on the non-mouse side to study differences in muscular responses potentially related to the risk of developing shoulder symptoms which were more prevalent on the mouse side. The number of EMG gaps on the mouse side were significantly lower than the values for the upper trapezius on the non-mouse side indicating that more continuous activity was present in the upper trapezius muscle on the mouse side and EVA analyses showed a more repetitive muscle activity pattern on the mouse side. These findings may be of importance to explain differences in the prevalence of shoulder symptoms.

The safety and effectiveness of esmolol in the perioperative period in patients undergoing abdominal aortic surgery

OBJECTIVES

To determine (1) if perioperative use of esmolol in major vascular surgery patients provides strict heart rate (HR) control, (2) what doses of esmolol are required to do this, and (3) does this control influence myocardial ischemia or result in adverse consequences.

DESIGN

Prospective study of 40 patients randomized to two groups: The HR was controlled to either less than 80 beats/min (group 80) or less than 110 beats/min (group 110) using esmolol. Patients were monitored continuously for electrocardiographic changes perioperatively. HR control began after induction of anesthesia and continued for 48 hours thereafter.

SETTING

Operating room and intensive care unit.

PATIENTS

Patients undergoing abdominal vascular surgery involving aortic cross-clamping.

INTERVENTIONS

Esmolol was titrated until the target HR was met.

MEASUREMENTS AND RESULTS

Only one patient demonstrated an adverse effect. The median infusion rates were 100 and 12.5 microg/kg/min for groups 80 and 110. Target HR was met less in group 80 than in group 110, primarily in the postoperative period. Ischemia patterns were not significantly different between groups.

CONCLUSION

Using esmolol for HR control in the intraoperative period for abdominal vascular surgery patients is effective and safe. HR control was much less effective in the postoperative period, but esmolol is safe when used at recommended doses. Further study with a larger number of patients is necessary to determine whether strict HR control with esmolol affects the incidence of myocardial ischemia or infarction in this patient population.