Extended cavity diode laser master-oscillator-power-amplifier for operation of an iodine frequency reference on a sounding rocket.

We present a hybrid microintegrated diode laser module developed for iodine spectroscopy on board a sounding rocket. The laser module is based on a master-oscillator-power-amplifier concept: an extended cavity diode laser serves as the master oscillator, and a ridge-waveguide semiconductor optical amplifier provides the power boost. The module's form factor and mass correspond to 12.5×7.5×2.3cm3 and 750 g, respectively. With an electrical power of 3.75 W supplied to the module, 570 mW of optical power is provided out of a polarization maintaining optical fiber at 1064.490 nm with a technical linewidth of 13 kHz (55 kHz) at a 1 ms (10 ms) time scale. The laser module has successfully passed vibration tests at a level of 8.8g R M S . A nominally identical module has recently been used to demonstrate, for the first time, precision iodine spectroscopy in space.

Impact of body mass index on outcome in stroke patients treated with intravenous thrombolysis.

BACKGROUND AND PURPOSE: The impact of body mass index (BMI) on outcome in stroke patients treated with intravenous thrombolysis (IVT) was investigated. METHODS: In a multicentre IVT-register-based observational study, BMI with (i) poor 3-month outcome (i.e. modified Rankin Scale scores 3-6), (ii) death and (iii) symptomatic intracranial haemorrhage (sICH) based on criteria of the ECASS II trial was compared. BMI was used as a continuous and categorical variable distinguishing normal weight (reference group 18.5-24.9 kg/m2 ) from underweight (<18.5 kg/m2 ), overweight (25-29.9 kg/m2 ) and obese (≥30 kg/m2 ) patients. Univariable and multivariable regression analyses with adjustments for age and stroke severity were done and odds ratios with 95% confidence intervals [OR (95% CI)] were calculated. RESULTS: Of 1798 patients, 730 (40.6%) were normal weight, 55 (3.1%) were underweight, 717 (39.9%) overweight and 295 (16.4%) obese. Poor outcome occurred in 38.1% of normal weight patients and did not differ significantly from underweight (45.5%), overweight (36.1%) and obese (32.5%) patients. The same was true for death (9.5% vs. 14.5%, 9.6% and 7.5%) and sICH (3.9% vs. 5.5%, 4.3%, 2.7%). Neither in univariable nor in multivariable analyses did the risks of poor outcome, death or sICH differ significantly between BMI groups. BMI as a continuous variable was not associated with poor outcome, death or sICH in unadjusted [OR (95% CI) 0.99 (0.97-1.01), 0.98 (0.95-1.02), 0.98 (0.94-1.04)] or adjusted analyses [OR (95% CI) 1.01 (0.98-1.03), 0.99 (0.95-1.05), 1.01 (0.97-1.05)], respectively. CONCLUSION: In this largest study to date, investigating the impact of BMI in IVT-treated stroke patients, BMI had no prognostic meaning with regard to 3-month functional outcome, death or occurrence of sICH.

Laser cooling of beryllium ions using a frequency-doubled 626 nm diode laser.

We demonstrate laser cooling of trapped beryllium ions at 313 nm using a frequency-doubled extended cavity diode laser operated at 626 nm, obtained by cooling a ridge waveguide diode laser chip to -31°C. Up to 32 mW of narrowband 626 nm laser radiation is obtained. After passage through an optical isolator and beam shaping optics, 14 mW of 626 nm power remains of which 70% is coupled into an external enhancement cavity containing a nonlinear crystal for second-harmonic generation. We produce up to 35 µW of 313 nm radiation, which is subsequently used to laser cool and detect 6×10(2) beryllium ions, stored in a linear Paul trap, to a temperature of about 10 mK, as evidenced by the formation of Coulomb crystals. Our setup offers a simple and affordable alternative for Doppler cooling, optical pumping, and detection to presently used laser systems.

High-power distributed Bragg reflector ridge-waveguide diode laser with very small spectral linewidth.

We manufactured and investigated distributed Bragg reflector ridge-waveguide diode lasers having sixth-order surface gratings and an emission wavelength around 974 nm. The single-mode output power of the lasers with a total length of 4 mm exceeded 1 W. A very small spectral linewidth of 1.4 MHz (3 dB) consisting of a Lorentzian part of 146 kHz and a Gaussian part of 1308 MHz was measured using a self-delayed heterodyne measurement technique.

Low-noise, tunable diode laser for ultra-high-resolution spectroscopy.

We demonstrate the excellent spectral properties of a diode laser setup that combines good tunability with superb short-term frequency stability and controllability. It is based on merging two concepts, the diode laser with resonant optical feedback and the grating stabilized diode laser. To characterize the short-term performance we beat two essentially identical diode lasers and find a short-term linewidth of ~11 kHz. Phase locking between these lasers is achieved with a servo bandwidth as small as 46 kHz, although an analog phase detector is used that requires subradian residual phase error. Despite small phase error detection range and small servo bandwidth, cycle-slip-free phase locking is accomplished for typically many 10 min, and the optical power is essentially contained in a spectral window of less than 20 mHz relative to the optical reference. Due to the excellent performance this laser concept is well suited for atomic or molecular coherence experiments, which require phase locking of different lasers to each other, and as part of a flywheel for optical clocks.

Diagnostics and therapy of lymphoceles after kidney transplantation.

Lymphocele incidence after kidney transplantation is as high as 18%. We retrospectively studied the therapy of 42 lymphoceles that occurred in our clinic between 1990 and 2005, focusing on possible predisposing factors for their formation and the results of several therapy variants: conservative, operative, percutaneous puncture, and laparoscopic or open marsupialization. There was no connection between lymphocele formation and the following parameters: the extent to which the iliac vessels had been prepared, the materials used for the preparation, or whether clips or ligatures were applied. Lymphoceles may originate either from the lymphatic system of the recipient or the transplanted kidney. The most sensible measures to prevent their occurrence therefore seems to be to restrict the transplant bed to the smallest permissible level with careful ligature of the lymphatic vessels in the area of the kidney hilus. Treatment for lymphoceles should start with minimally invasive measures. We use the following algorithm in our clinic: puncture to differentiate between urinoma/lymphocele and to test for bacterial infection, sclerotization (200 mg doxycyclin), and finally marsupialization if persistent. The choice of operative technique depends on the location. This algorithm resulted in a relapse rate of 9.5% during the postoperative observation period of up to 15 years.

Use of catheters with the AgION antimicrobial system in kidney transplant recipients to reduce infection risk.

Microbial blood infection represents a high risk for immuno-suppressed patients. Of all catheter-related infections in the bloodstream, 90% result from the use of central venous catheters, the main cause being microbial colonization at the catheter's insertion point or the catheter hub. Between January 2003 and December 2004, 102 patients received a renal transplant including 57 who received a triple-lumen central venous catheter (CVC) during the procedure. Two catheters were used: a standard polyurethane catheter placed in the jugular veina or the subclavian veina for group I, and polyurethane catheters with the AgION antimicrobial system always placed in the subclavian veina for group II. Care and maintenance of the CVCs was standardized in both groups. After catheter removal, the tips were analyzed microbiologically. Of 57 (43.9%) CVCs, 25 were found to be contaminated. In the first group 24 out of 41 CVCs (58.5%) showed bacterial growth, whereas in group II only one catheter (6.6%) had a biofilm. The most common contaminant (18 out of 25, 72%) was Staphylococcus epidermidis. In group II, two patients had positive blood cultures yet a microbiologically sterile CVC. None of the catheters with the AgION antimicrobial system had to be removed owing to local infection or intolerance. The continuous release of silver ions increases the protection against bacteria and fungi during the entire time of catheterization. Use of catheters with the AgION antimicrobial system lead to a marked reduction in catheter-associated infections of the bloodstream.

Subcutaneous penile vein thrombosis (Penile Mondor's Disease): pathogenesis, diagnosis, and therapy.

OBJECTIVES: In international studies, only a few data are available on subcutaneous penile vein thrombosis. The pathogenesis is unknown, and no general recommendation exists regarding therapy. METHODS: A total of 25 patients with the clinical picture of a "superficial penile vein thrombosis" were treated at our policlinic. All patients had noted sudden and almost painless indurations on the penile dorsal surface. The extent of the thrombosis varied. Detailed anamnesis, ultrasonography, and routine laboratory tests were performed for all patients, knowing that primary therapy was conservative. RESULTS: No patient indicated any pain. Some reported a feeling of tension in the area of the thrombosis. In all patients, the thrombosis occurred in the dorsal penis shaft. It was close to the sulcus coronarius in 21 patients, near the penis root in 3, and in the entire penis shaft in 1 patient. The length of the thrombotic vein was between 2 and 4 cm. The ultrasound results were similar for all patients. The primary treatment was conservative for all patients. Recovery was achieved in more than 92% of cases (23 of 25 patients) using conservative therapy, which consisted of local dressing with heparin ointment (10,000 IU) and oral application of an antiphlogistic for 14 days. In 2 cases, thrombectomy was necessary. CONCLUSIONS: Extended imaging diagnosis does not improve the evaluation of the extent of a superficial penile vein thrombosis. Conservative primary therapy consisting of heparin ointment and oral application of antiphlogistics is sufficient. If the thrombosis persists after conservative therapy, surgery is indicated.

[Diagnostics and treatment of prostate cancer after kidney transplantation]. / Diagnostik und Therapie des Prostatakarzinoms nach Nierentransplantation.

The number of patients with prostate cancer and end-stage renal disease or prostate cancer following kidney transplantation has continuously increased in industrialized countries. According to the data generated by Penn et al. a higher incidence of prostate cancer following kidney transplantation can be seen but is probably due to a more intense screening of the recipients. It is rather a common opinion that no elevated risk of prostate cancer following kidney transplantation exists. In patients with strictly localized prostate cancer curative treatment should be the aim also after kidney transplantation. Kidney transplantation does not interfere with surgical access to the prostate gland (retropubic or perineal). Nonlocal tumors of the prostate should also be treated following the general recommendations regarding prostate cancer. Looking at the current literature, a reduction or change of immunosuppression seems reasonable. It is necessary to establish a nationwide (or even European) cancer register, especially for patients before and after transplantation.

[Questionnaire on crossover renal transplantations in Germany]. / Umfrage zur Uberkreuznierentransplantation in Deutschland.

Due to increasingly better long-term survival rates with dialysis the number of patients with renal failure constantly increases by 4% annually worldwide. Despite great progress in operative and perioperative management as well as improved immunosuppressive drugs, kidney transplantation still faces two major problems. First of all there is a huge deficit of donor organs and secondly the long-term results of the kidney grafts must be improved. One way to relieve this tense situation may be live kidney donation. In many countries not participating in Eurotransplant, especially the United States and Scandinavia, live kidney donation is performed more often than kidney transplantation from deceased donors. Germany implemented a transplantation law in December 1997. This law also regulates living donation, with exclusion of crossover transplantations. Cross-over transplantation is a special variation of live donation for couples who cannot donate/receive in their respective couple constellation. Therefore, the donor of the one couple donates his/her kidney to the recipient of the other couple and vice versa. According to German legislation this is illegal. We performed a study in order to evaluate the opinions of the German kidney transplant centers on crossover kidney transplantations. The majority of the German transplantation centers believe that crossover transplantation is acceptable with regard to ethical and medical concerns. To enable this kind of kidney transplantation the transplantation law would have to be changed. Nevertheless, nationwide polls show that live kidney donation represents only a very small portion of all transplantations taking place. Live kidney donation should be granted higher priority as dialysis triggers psychological and physical damage, especially in children. For many patients live kidney donation is the only chance for early transplantation with an excellent long-lasting kidney graft function.

[Histamine in tears in allergic rhinoconjunctivitis]. / Histamin in der Tränenflüssigkeit bei allergischer Rhinokonjunktivitis.

UNLABELLED: The classic clinical symptoms of allergic conjunctivitis (type I allergy)--itching and lacrimation--are the effect of histamine. Determination of histamine levels in tears may be useful in evaluating the dynamics of local histamine release in connection with the clinical findings. PATIENTS AND METHODS: Between 1.7.1994 and 31.6.1995 we analyzed the histamine levels in tears and investigated the clinical symptoms (score of 0-3) of 32 hyposensitized pollen-sensitive patients (14 males and 18 females, aged 18-45 years, group I) and of 32 controls (group II) without any allergic disease, performed in each case once in season and once out of season. Tear production and composition were measured by Schirmer's test and tear break-up time at the same time. The histamine levels of the tear samples (obtained by microcapillary method) were analyzed by electrochemical determination. RESULTS: In group I there was a highly significant increase of the mean histamine level from 0.89 +/- 2.22 ng/ml (out of season) to 7.71 +/- 7.51 ng/ml (in season) for the right eye and from 0.73 +/- 2.36 ng/ml (out of season) to 9.51 +/- 9.07 ng/ml (in season) for the left eye (P = 0.0000). The histamine level in tears of the controls (group II) was below the detection limit in all samples. The seasonal histamine level were higher with the severity of atopy (Erlangen atopy score). There was no significant influence of age and gender. The reduction of allergic symptoms during hyposensitization was not comparable to the degree of seasonal histamine level. Compared with the clinical findings, the histamine level in tears did not correlate with the symptoms of lacrimation, itching and conjunctival hyperemia. CONCLUSION: The histamine level in tears alone is not useful as a marker for the clinical severity of this atopyassociated disorder and for the efficacy of the anti-allergic therapy. After standardization of the determination method and the identification of other soluble mediators simultaneously, the histamine level in tears can be used as one part of a profile of mediators to evaluate the clinical symptoms.