Measurement of the helicity asymmetry E for the reaction γ p → π 0 p : The CBELSA/TAPS Collaboration.

A measurement of the double-polarization observable E for the reaction γ p → π 0 p is reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol (C 4 H 9 OH) target, which provided longitudinally-polarized protons. Circularly-polarized photons were produced via bremsstrahlung of longitudinally-polarized electrons. The data cover the photon energy range from E γ = 600 to 2310 MeV and nearly the complete angular range. The results are compared to and have been included in recent partial wave analyses.

N(1520) 3/2(-) helicity amplitudes from an energy-independent multipole analysis based on new polarization data on photoproduction of neutral pions.

New data on the polarization observables T, P, and H for the reaction γp→pπ(0) are reported. The results are extracted from azimuthal asymmetries when a transversely polarized butanol target and a linearly polarized photon beam are used. The data were taken at the Bonn electron stretcher accelerator ELSA using the CBELSA/TAPS detector. These and earlier data are used to perform a truncated energy-independent partial wave analysis in sliced-energy bins. This energy-independent analysis is compared to the results from energy-dependent partial wave analyses.

First measurement of the helicity asymmetry for γp → pπ0 in the resonance region.

The first measurement of the helicity dependence of the photoproduction cross section of single neutral pions off protons is reported for photon energies from 600 to 2300 MeV, covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, and BnGa partial wave analyses. Strikingly large differences between data and predictions are observed, which are traced to differences in the helicity amplitudes of well-known and established resonances. Precise values for the helicity amplitudes of several resonances are reported.

Well-established nucleon resonances revisited by double-polarization measurements.

The first measurement is reported of the double-polarization observable G in the photoproduction of neutral pions off protons, covering the photon energy range from 620 to 1120 MeV and the full solid angle. G describes the correlation between the photon polarization plane and the scattering plane for protons polarized along the direction of the incoming photon. The observable is highly sensitive to contributions from baryon resonances. The new results are compared to the predictions from SAID, MAID, and BnGa partial wave analyses. In spite of the long-lasting efforts to understand γp→pπ(0) as the simplest photoproduction reaction, surprisingly large differences between the new data and the latest predictions are observed which are traced to different contributions of the N(1535) resonance with spin parity J(P)=1/2(-) and N(1520) with J(P)=3/2(-). In the third resonance region, where N(1680) with J(P)=5/2(+) production dominates, the new data are reasonably close to the predictions.

[Management and outcome of vein of galen malformation in childhood]. / Management und Outcome der Vena-Galeni-Malformation im Kindesalter.

The vein of Galen malformation (VGM) is a rare congenital cerebral vascular malformation. In most cases it already has been diagnosed prenatally. The impact of heart failure due to the arteriovenous shunt is relevant for the prognosis.Prognosis of neonatal symptomatic VGM with early heart failure is severe. Therefore an interdisciplinary cooperation is necessary and it is important to treat patients in a clinic with a perinatal center and a neuroradiology and neurosurgery that is experienced in treating such patients. The genesis, the pathophysiology, the diagnostic agents, the therapeutic agents and the prognosis of VGM will be described.

Slow and fast inhibition and an H-current interact to create a theta rhythm in a model of CA1 interneuron network.

The oriens-lacunosum moleculare (O-LM) subtype of interneuron is a key component in the formation of the theta rhythm (8-12 Hz) in the hippocampus. It is known that the CA1 region of the hippocampus can produce theta rhythms in vitro with all ionotropic excitation blocked, but the mechanisms by which this rhythmicity happens were previously unknown. Here we present a model suggesting that individual O-LM cells, by themselves, are capable of producing a single-cell theta-frequency firing, but coupled O-LM cells are not capable of producing a coherent population theta. By including in the model fast-spiking (FS) interneurons, which give rise to IPSPs that decay faster than those of the O-LM cells, coherent theta rhythms are produced. The inhibition to O-LM cells from the FS cells synchronizes the O-LM cells, but only when the FS cells themselves fire at a theta frequency. Reciprocal connections from the O-LM cells to the FS cells serve to parse the FS cell firing into theta bursts, which can then synchronize the O-LM cells. A component of the model O-LM cell critical to the synchronization mechanism is the hyperpolarization-activated h-current. The model can robustly reproduce relative phases of theta frequency activity in O-LM and FS cells.

[Diagnostics and surgical therapy of enteric intussusception in adults illustrated by three cases]. / Dünndarminvagination beim Erwachsenen. Diagnostik und chirurgische Therapie anhand von 3 Fallbeispielen.

The diagnosis of enteric intussusception is rare in adults but not in children. The clinical picture often takes an insidious course. Acute abdomen may also be caused by enteric intussusception. We report on three patients with enteric intussusception and acute abdomen. In two cases, a CT led to the diagnosis of invagination of the small intestine. In one patient, invagination of the terminal ileum was detected during coloscopy. All patients were submitted to limited segment resection and end-to-end anastomosis. In all three cases, the invagination was caused by benign pathological changes. Enteric intussusception in adults always requires surgery. In more than 95% of the cases, pathological findings are obtained intraoperatively, which are benign in the small intestine in 85-95% of the cases.

[Evaluation of syncope in children with tilt table test]. / Synkopenabklärung bei Kindern mittels Kipptischuntersuchung.

Tilt table testing is a well approached examination for differentiating unexplained syncope and control trial after therapy. It is evaluated at children and is fast and reliable in spite of high personality effort. We present the indication of examination, course of examination, additional procedures like transcranial doppler sonography, reaction models during the tilt table examination and treatment features for neurocardiogenic syncope.

[Value of transcranial Doppler sonography during tilt table test in children]. / Wertigkeit der transkraniellen Dopplersonographie in der Kipptischuntersuchung bei Kindern.

AIM: Transcranial Doppler sonography was used to asses time relation and characteristically changes in middle cerebral artery blood flow velocity before syncope during tilt table test in children. METHOD: We performed tilt table tests in 40 pediatric patients with a medical history for syncope after exclusion of neurologic and cardiologic diseases. Examination was done in a 70 degrees postural position under control of electrocardiogram, blood pressure measurement and measurements of blood flow velocity of middle cerebral artery by transcranial Doppler with 3-MHz probe. RESULTS: In 13 children syncope occurred after 5 to 45 min (average 23.3). 10 of them were neurocardiogenic syncopes. With it diastolic and medium blood flow velocity of middle cerebral artery initial ever increased while resistance and pulsatility index decreased. Just before syncope the diastolic blood flow velocity decreased dramatically thus no diastolic blood flow could be measured, respectively. Almost we could measure no diastolic blood flow just before syncope occurred. CONCLUSION: Patients with neurocardiogenic syncope do have characteristically blood flow velocity changes of middle cerebral artery just before loosing consciousness. Transcranial Doppler is a usefully examination during tilt table. Clear transcranial Doppler results can help to prevent children from the impending syncope.

Does gastric juice pH influence tonometric PCO2 measured by automated air tonometry?

To determine the influence of changes in gastric juice pH due to intravenous administration of pentagastrin and omeprazole on intramucosal regional PCO2 (Pr(CO2)), we investigated 17 healthy human volunteers. Gastric juice pH was obtained from a glass pH electrode for continuous gastric juice pH measurement and Pr(CO2))was measured by using automated air tonometry. After baseline (8:00 A.M.-9:00 A.M.) the subjects received 0.6 microg/kg/h pentagastrin intravenously for 1 h (9:00 A.M.-10:00 A.M., after stimulation 10:00 A.M.-11:00 A.M.) and 40 mg omeprazole intravenously (after omeprazole 11:00 A.M.-3:00 P.M.). Following pentagastrin administration gastric juice pH significantly decreased from 1.2 +/- 0.4 to 0.6 +/- 0.4 (mean +/- SD, p < 0.007, versus baseline), whereas omeprazole transiently increased luminal pH up to 4.4 +/- 1.7 (p < 0.007 versus baseline). These subsequent changes in gastric juice pH were accompanied by a significant increase in Pr(CO2) from 48 +/- 12 to 61 +/- 17 mm Hg (p < 0.007 versus baseline) and a decrease to 44 +/- 5 mm Hg (p < 0.002 versus pentagastrin), respectively. A gastric juice pH > 4 considerably reduces mean gastric Pr(CO2) and interindividual variability. Thus omeprazole may improve the validity of gastric tonometry data.

Efficacy of silver-coating central venous catheters in reducing bacterial colonization.

OBJECTIVE: To compare silver-coated and uncoated central venous catheters regarding bacterial colonization. To assess the relative contribution of catheter hub and skin colonization to catheter tip colonization. DESIGN: Prospective, randomized clinical trial. SETTING: Intensive care unit in a university hospital. PATIENTS: Patients after cardiac surgery who required a central venous double-lumen catheter (DLC). INTERVENTIONS: Sixty-seven adult patients were prospectively randomized to receive either a silver-coated (S group, n = 34) or an uncoated control (C group, n = 33) DLC. Blood cultures were drawn at catheter removal, and removed catheters were analyzed with quantitative cultures. Typing of microorganisms included DNA fingerprinting. MEASUREMENTS AND MAIN RESULTS: Catheters were removed if no longer necessary and aseptically divided into three segments: segment A, the catheter tip; segment B, an intermediate section; and segment C, the subcutaneous portion. Bacterial catheter colonization was quantitatively measured using sonication to detach adherent bacteria from the catheter segments in the broth and subsequent culture of an aliquot. Selected isolates of coagulase-negative staphylococci and other bacteria from catheter segments were examined by means of pulsed-field gel electrophoresis (PFGE) after macrorestriction digestion of bacterial DNA to study colonization pathogenesis. Quantitatively lower bacterial colonization could be demonstrated on the silver-coated catheters (200 +/- 550 colony forming units [CFUs]/cm catheter segment; mean +/- SD). The difference in the control catheters (1120 +/- 5350 CFUs/cm catheter segment; mean +/- SD) was not, however, significant (p = .25). The frequency of colonization of at least one catheter segment was 52.9% for the silver-coated catheters and 57.6% for the control catheters (p= .44), without any significant differences in the colonization of corresponding catheter segments. The rate of significant catheter colonization (i.e., > or = 10(3) CFUs/cm catheter by quantitative catheter culture or > or = 10(3) CFUs/mL by luminal flush) was nine in the silver group and seven in the control group, a difference that failed to reach significance (p = .41). Two patients in both groups developed catheter-related bacteremia. Pattern analysis after PFGE demonstrated that about 70% of the isolates found on the catheter tip were identical with those on the skin at the insertion site, whereas about 75% were identical with those recovered from the hub. In 29% of colonized catheters, identical bacteria were found on the hub and the skin at the insertion site. CONCLUSIONS: Silver-coating of DLCs did not significantly reduce bacterial catheter colonization compared with the control catheters. PFGE analysis of coagulase-negative staphylococci and other bacteria demonstrated various pathogenic routes of catheter-related colonization, whereby the microorganisms of the skin flora around the insertion site must be regarded as the main source of catheter-related infections.

cMeso-1, a novel bHLH transcription factor, is involved in somite formation in chicken embryos.

The segmentation of somites from the paraxial mesoderm is a crucial event in vertebrate embryonic development; however, the mechanisms underlying this process are not well understood. In a yeast two-hybrid screen we have identified the novel basic-helix-loop-helix (bHLH) protein cMeso-1 which is expressed in the presomitic mesoderm of early chicken embryos. Initially the gene is activated in the epiblast and transcripts concentrate later in and around the primitive streak. When the segmental plate is laid down the cMeso-1 expression domain successively retracts toward the caudal end but a second domain appears in bilateral stripes in the anterior paraxial mesoderm. This highly dynamic domain of cMeso-1 transcripts demarcates the area immediately posterior to the next prospective pair of somites in cyclic waves which apparently correspond to the formation of new somites. Loss of cMeso-1 function by antisense RNA or oligonucleotides results in severe attenuation of somitogenesis suggesting that it plays an important role in setting up the segmentation process. The dynamic and periodically reiterated expression of cMeso-1 along the anteroposterior axis is not dependent on anterior structures or the propagation of a signal along the anteroposterior axis but seems to follow an intrinsic patterning program which is already set up in the segmental plate.

[The efficacy of radiotherapy in vertebral hemangiomas]. / Effizienz der Strahlentherapie bei Wirbelhämangiomen.

AIM: Assessment of the efficacy of radiation therapy for symptomatic vertebral hemangiomas. PATIENTS AND METHODS: Records of 19 patients who were treated from 1969 to 1988 were retrospectively analyzed. Radiation treatment was given at 2 Gy per fraction to 20 Gy (n = 2), 30 Gy (n = 11), or 40 Gy (n = 6). Improvement of symptoms was chosen to determine the efficacy of the treatment. In addition the lesions were controlled radiographically. RESULTS: Symptomatic improvement was achieved in 17 of 19 patients, remission was complete in 7 patients. No dose-response relationship was observed. The median time to improvement of symptoms was 3 months. The radiographic controls did not correlate with the clinical course. CONCLUSIONS: Radiation therapy is an effective treatment for symptomatic vertebral hemangiomas. The aim of the treatment is to ameliorate clinical symptoms, radiographic improvement is of minor importance.

"Stuck twin" syndrome associated with congenital cytomegalovirus infection.

A case is reported of presumed twin-twin transfusion syndrome successfully treated with amniocentesis and also complicated by congenital cytomegalovirus infection and second trimester exposure to high-dose ibuprofen with temporally related ductal narrowing.

Sequence variation in the E7 gene of human papillomavirus type 18 in tumor and non-tumor patients and antibody response to a conserved seroreactive epitope.

We have determined nucleotide sequences of the E7 open reading frame (ORF) of human papillomavirus type 18 (HPV-18) isolates obtained from 18 cervical carcinomas from Tanzanian and German patients and 8 cervical scrapings from Tanzanian non-tumor patients. The HPV-18 prototype sequence was detected in only 3 out of 26 isolates. Silent mutations were found at nt positions 640 and 751, whereas the mutations observed at nt positions 770, 806, 864 and 865 all change the respectively encoded amino acid. The HPV-18 isolates of 3 German carcinomas showed the same mutations (at position 751) as those of 2 established cervical carcinoma cell lines (HeLa and C4-1), whereas different mutations were found in 16/23 African isolates (at positions 640 and 864), to which the isolate of cell line SW756 was similar (changes at positions 640 and 865). Seven out of 15 HPV-18-positive Tanzanian tumor patients (46.7%) reacted in a peptide ELISA against a recently described seroreactive epitope of the HPV-18 E7 ORF (nt positions 704-769). Mutational changes of the E7 ORF were excluded as a possible explanation for the lack of antibody response, because there was no correlation with the serological results. The seroreactive region appears to be well conserved despite geographically varying mutations within the E7 ORF of HPV-18.

Geographical dependence of sequence variation in the E7 gene of human papillomavirus type 16.

We have determined nucleotide sequences of the E7 open reading frame (ORF) of human papillomavirus type 16 (HPV-16) isolates obtained from 32 genital tumours and two HPV-16-transformed human keratinocyte cell lines. In comparison to the prototype HPV-16 isolated from a German cervical cancer biopsy, no sequence variations were noticed in either the two cell lines or the 10 biopsies that were obtained from German patients. In contrast only three of 22 (13.6%) of Tanzanian isolates showed the prototype sequence. In 18 of these biopsies two alterations (T to C and T to G) not affecting the amino acid sequence were found within the HPV-16 E7 ORF (nucleotide positions 789 and 795) but eight of these isolates contained an additional change (nucleotide position 647) coding for serine instead of asparagine (amino acid position 29). One tumour harbours HPV-16 DNA with a mutation (C to T) at nucleotide 790 changing the E7 amino acid sequence (arginine to cysteine) at position 76. Our findings suggest that clustering of E7 sequence variants may occur in different geographical regions of the world.

Human papillomavirus (HPV) infection, HIV infection and cervical cancer in Tanzania, east Africa.

The presence of HPV-DNA was determined in tumor biopsies of cervical-cancer patients and in cervical swabs of non-cancer patients from Tanzania, East Africa, by Southern blot hybridization and/or PCR. HPV types 16 and 18 were detected in 38% and 32%, respectively, of 50 cervical-carcinoma biopsies. A consensus primer PCR capable of detecting a broad spectrum of HPV types revealed the presence of HPV-DNA in 59% of 359 cervical swabs of non-cancer patients. Type-specific PCR showed that types 16 and 18 accounted for 13.2% and 17.5%, respectively, of all HPV infections. Therefore we concluded that HPV 18 is more prevalent in Tanzania than in any other geographical location so far reported. The strongest risk factors for the presence of any HPV-DNA in the 359 female non-cancer patients were young age and HIV infection. The epidemiology of HPV types 16 and 18 was found to differ from that of other HPV types, being associated in univariate analysis with trichomonas vaginalis infection, martial status (single/divorced), age at first intercourse, and young age at menarche. However, young age at menarche accounted for most of the effects of all other, variables in multivariate analysis. Of the non-cancer patients, 12.8% had antibodies against HIV I (no patient being severely symptomatic), and HIV infection was highly correlated with the presence of HPV-DNA, especially types 16 and 18. While HPV-DNA of any type was detectable 1.4-fold more often in HIV-positive patients than in HIV-negative patients, evidence of an infection with HPV types 16 or 18 was found 2.2-fold more often in the HIV-positive patients. The HIV-positive women did not show an increased rate of cervical cytological abnormalities as assessed by PAP staining of a single cervical smear, the overall rate of abnormalities being 2.8%. Furthermore, the age-adjusted prevalence of HIV antibodies was found to be considerably lower in 270 cervical-carcinoma patients (3% HIV-positive) in comparison with non-cancer patients. Thus there was no association observable between the prevalence of HIV infections and the frequency of cervical cytological abnormalities or cervical cancer in the setting of this cross-sectional study.

PIP: Southern blot hybridization and/or PCR was used to examine tumor biopsies of 53 women with cervical or vaginal cancer at Ocean Road Hospital in Dar es Salaam, Tanzania, and the cervical swabs of 359 women with no cancer at the gynecologic clinic at Muhimbili University College of Health Sciences in Dar es Salaam. Tanzanian and German scientists wanted to determine whether an association existed between human papillomavirus (HPV) infections and HIV, and whether the high prevalence of HIV infection was matched by a high prevalence of HPV infections, cervical dysplasias, and cervical cancer in HIV-positive cases. 59% of the noncancerous women had HPV-DNA. Young age and HIV infection were the greatest risk factors for HPV-DNA in these women (p .0001 for age and HPV-16/18; p = .08 for other HPVs; and p = .03 for HIV). 13.2% and 17.5% of all HPV infections were HPV types 16 and 18, respectively. Tanzania had the highest prevalence of HPV 18 ever reported. HPV-16/18 risk factors included: Trichomonas vaginalis infection (odds ratio [OR] = 2.23; p = .04), single status (OR = 2.55; p = .01), 16 years old or less at first intercourse (OR = 2.1; p = .03), and young age at menarche (OR = 6 for or=12 years old; p = .02 and OR = 3.25 for or=13 years old and or=16 years old; p = .05). Yet, the multivariate analysis revealed young age at menarche had the greatest effect (OR = 6.2 for or= 12 years old, p = .03; OR = 3.73 for or=16 years old, p = .08). 12.8% of noncancerous women tested positive for HIV-1, but none of them were obviously symptomatic. These HIV-positive women had a higher OR if they had HPV-16/18 than if they had other HPV types (4.25 vs. 2.02). Further, they did not have more cervical cytological abnormalities than did the HIV-negative women (overall cervical cytological abnormality rate - 2.8%). The HIV-positive rate for cancerous patients was only 3%. In conclusion, no association existed between HIV infection and cervical cytological abnormalities or cervical cancer.