Watt-level and sub-100-fs self-starting mode-locked 2.4-µm Cr:ZnS oscillator enabled by GaSb-SESAMs.

Femtosecond lasers with high peak power at wavelengths above 2 µm are of high interest for generating mid-infrared (mid-IR) broadband coherent light for spectroscopic applications. Cr2+-doped ZnS/ZnSe solid-state lasers are uniquely suited since they provide an ultra-broad bandwidth in combination with watt-level average power. To date, the semiconductor saturable absorber mirror (SESAM) mode-locked Cr:ZnS(e) lasers have been severely limited in power due to the lack of suitable 2.4-µm SESAMs. For the first time, we develop novel high-performance 2.4-µm type-I and type-II SESAMs, and thereby obtain state-of-the-art mode-locking performance. The type-I InGaSb/GaSb SESAM demonstrates a low non-saturable loss (0.8%) and an ultrafast recovery time (1.9 ps). By incorporating this SESAM in a 250-MHz Cr:ZnS laser cavity, we demonstrate fundamental mode-locking at 2.37 µm with 0.8 W average power and 79-fs pulse duration. This corresponds to a peak power of 39 kW, which is the highest so far for any saturable absorber mode-locked Cr:ZnS(e) oscillator. In the same laser cavity, we could also generate 120-fs pulses at a record high average power of 1 W. A comparable laser performance is achieved using type-II InAs/GaSb SESAM as well. These results pave the way towards a new class of high-power femtosecond SESAM mode-locked oscillators operating directly above 2-µm wavelength.

High-speed interband cascade infrared photodetectors: photo-response saturation by a femtosecond oscillator.

Interband cascade infrared photodetectors (ICIPs) combine interband optical transitions with fast intraband transport to achieve high-frequency and broad-wavelength operation at room temperature. Here we study the bias-dependent electronic impulse response of ICIPs with a mid-infrared synchronously pumped optical parametric oscillator (OPO). Since the OPO produces ultrashort 104-fs pulses, it is possible to probe the impulse response of the ICIP. From this impulse response, we identify two characteristic decay times, indicating the contribution of electron as well as hole carriers. A reverse bias voltage applied to the ICIP reduces both time scales and leads to an increased electrical cut-off frequency. The OPO emits up to 500 mW average power, of which up to 10 mW is directed to the ICIP in order to test its saturation characteristics under short-pulse illumination. The peak of the impulse response profile as well as the average photocurrent experience a gradual saturation behavior, and we determine the corresponding saturation powers by measuring the photo-response as a function of average power directed to the ICIP. We demonstrate that an increasing reverse bias increases the saturation power as well as the responsivity of the ICIP.

Digital mammography screening: sensitivity of the programme dependent on breast density.

OBJECTIVES: To analyse the impact of breast density on the sensitivity of a population-based digital mammography screening programme (SP) as key evaluation parameter. METHODS: 25,576 examinations were prospectively stratified from ACR category 1 to 4 for increments of 25 % density during independent double reading. SP was calculated as number of screen-detected cancers divided by the sum of screen-detected plus interval cancers (24-months period) per ACR category, related to the first reading (a), second reading (b) and highest stratification if discrepant (c). Chi-square tests were used for comparison. RESULTS: Overall sensitivity of the programme was 79.9 %. SP in ACR 4 (a: 50 %, b: 50 %, c: 50 %) was significantly lower than in ACR 3 (a: 72.9 %, b: 79.4 %, c: 80.7 %, p < 0.001), ACR 2 (a: 83.9 %, b: 85.7 %, c: 83.2 %, p < 0.001) and ACR 1 (a: 100 %, b: 88.8 %, c: 100 %; p < 0.001). Frequencies of ACR 4 were a: 5.0 %, b: 4.3 %, c: 6.9 %. CONCLUSION: Digital mammography screening with independent double reading leads to a high overall SP. In the small group of women with breast density classified as ACR 4 SP is significantly reduced compared to all other ACR categories. KEY POINTS: • Overall sensitivity of a population-based digital mammography screening programme (SP) was 79.9 %. • In women with ACR 1, 2, or 3, SP ranged between 72.9 %-100 %. • ACR 4 was rare in participants (<7 %) and SP was only 50 %. • SP in ACR 4 differed significantly from ACR 3 (p < 0.001).

Variations in the use of diagnostic procedures after acute stroke in Europe: results from the BIOMED II study of stroke care.

Valid classification of stroke is essential to initiate effective acute management and early secondary prevention strategies. To accurately evaluate stroke subtype a number of diagnostic procedures have to be performed. This study sought to investigate variations in use of diagnostic procedures across selected European hospitals. First-ever stroke patients were sampled over a 1-year period through 11 hospital-based registers across 10 European countries. We defined a diagnostic standard for valid aetiological classification of ischemic stroke including brain imaging, vascular imaging and echocardiography. The impact of socio-demographic, clinical and structural characteristics on performance of the diagnostic standard was assessed using multivariate logistic regression analyses. A total of 1721 patients were included in the study. 83.1% received brain imaging, ranging from 32.8% to 100%. The diagnostic standard was performed in 40.4% of stroke patients, ranging from 0% to 77.2%. Patients with increasing age (P < 0.001) and with more severe strokes (P = 0.001) were less probably to receive the diagnostic standard. Patients treated in stroke units and neurological departments were more frequently investigated with the diagnostic standard (P < 0.001). Less than half of hospitalized stroke patients across Europe underwent diagnostic procedures to allow for aetiological classification of stroke, which may hamper the initiation of effective early management and secondary prevention.

Liver flukes in dogs and treatment with praziquantel.

Opisthorchiid eggs were found in 6 out of 27 (22%) huskies while an ELISA detected antibodies against Opisthorchis felineus and Metorchis bilis in 24 (89%) and 25 (93%) sera taken from these dogs, respectively. All dogs showed an increased activity of glutamate dehydrogenase while aspartate aminotransferase was normal in all samples. Ten weeks after treatment with praziquantel no fluke eggs were found in the faeces from any animal and antibody titres dropped in all animals.

Reduction of Advanced Breast Cancer Stages at Subsequent Participation in Mammography Screening.

PURPOSE: The decline in advanced breast cancer stages is presumably the most relevant surrogate parameter in mammography screening. It represents the last step in the causal cascade that is expected to affect breast cancer-related mortality. To assess the effectiveness of population-based screening, we analyzed the 2-year incidence rates of advanced breast cancers between women participating in the initial and in the first subsequent round. MATERIALS AND METHODS: The study included data from 19,563 initial and 18,034 subsequent examinations of one digital screening unit (2008 - 2010). Data on tumor stages, detected by screening or within the following interval of two years (2-year incidence), were provided by the epidemiological cancer registry. Rates of all and combined UICC stages 2, 3 and 4 (advanced stages) were reported for a two-year period. Proportions were tested for significance by using chi-square tests (p < 0.001). RESULTS: The 2-year incidence rate of all stages was significantly lower in participants in subsequent screening than in initial screening (0.85 vs. 1.29 per 100 women (%); p < 0.0001). A significantly lower 2-year incidence of advanced stages was observed for subsequent screening compared to initial screening (0.26 % vs. 0.48 %; p = 0.0007). Among women aged 50 to 59 years, the incidence of advanced stages was less clearly different (0.21 % vs. 0.35 %; p = 0.07) than in women aged 60 to 69 years (0.31 % vs. 0.70 %; p = 0.0008). CONCLUSION: During the change from prevalent to incident phase mammography screening, a program impact is seen by a lower 2-year incidence of advanced breast cancers within subsequent compared to initial participants, predominately in women aged 60 to 69 years. KEY POINTS: • The incidence of advanced tumor stages represents the most relevant surrogate parameter for screening effectiveness. • For the first time the 2-year incidence of advanced breast cancer stages after subsequent mammography screening was analyzed. • We observed a significant effect of screening on the 2-year incidence of advanced stages, predominately in the age group 60 to 69 years.

Partial purification and characterization of lactate dehydrogenase from Plasmodium falciparum.

Lactate dehydrogenase (LDH) from Plasmodium falciparum was partially purified by two different procedures. In the first procedure, parasitized erythrocytes (80% parasitemia) were lysed, and the soluble fraction was purified on DEAE-Sephadex to separate the parasite LDH(LDH-P) from the LDH isoenzymes present in the human erythrocytes. LDH-P was then purified by high-performance liquid chromatography (HPLC) on a TSK-G-3000 SW protein column. This two-step procedure gave LDH-P with specific activity 85 micromol/min/mg protein; this represented a 700-fold increase in specific activity relative to the starting lysate. Alternatively, parasites of P. falciparum were isolated by mechanical rupture of infected erythrocytes followed by differential centrifugation. The 100,000 X g supernatant obtained after lysis of these parasites showed LDH-P specific activity 3.6 micromol/min/mg protein. This activity was free of contaminating erythrocyte LDH as determined by electrophoresis and specific staining for LDH. Further purification of LDH-P by HPLC, as before, gave material with specific activity 98 micromol/min/mg protein. Recoveries of activity on HPLC were more than 90%, demonstrating the usefulness of this procedure for the partial purification of small quantities of parasite protein. The kinetic properties of LDH-P were compared with those of two of the human isozymes, LDH-H4 and LDH-M4 . LDH-P resembles LDH-H4 in its kinetic properties: KM (NADH) is 7, 8.3 and 1.3 microM for LDH-P, LDH-H4 and LDH-M4, respectively; KM (pyruvate) is 30, 60 and 180 microM for LDH-P, LDH-H4 and LDH-M4. LDH-P differs significantly from LDH-H4 and LDH-M4 in that LDH-P is not sensitive to inhibition by high pyruvate nor sensitive to inhibition by the complex between NAD+ and pyruvate. LDH-P is inactivated within seconds by sodium deoxycholate at concentrations that do not affect LDH-H4 and slowly inactivate LDH-M4.

Educational level and risk profile of cardiac patients in the EUROASPIRE II substudy.

STUDY OBJECTIVE: To ascertain, whether, conventional risk factors and readiness of coronary patients to modify their behaviour and to comply with recommended medication were associated with education in patients with established coronary heart disease. DESIGN AND METHODS: EUROASPIRE II was a cross sectional survey undertaken in 1999-2000 in 15 European countries to ascertain how effectively recommendations on coronary preventions are being followed in clinical practice. Consecutive patients, men and women

Effect of Rous associated virus number 7 on lymphoid cells and tissues of the chicken.

Infection of chicks or chick embryos with Rous associated virus number 7 (RAV-7) led to a decreased blastogenic response to Concanavalin A (Con A) by lymphocytes isolated from the spleen and thymus. Chicks infected with RAV-7 8 days after hatch manifested decreased Con A blastogenesis 5 weeks postinfection, while chicks infected in ovo at 10 days of incubation showed an unusual pattern of cell density dependent decreased blastogenesis two weeks post-hatch (three weeks post-infection). Histopathological examination of tissues from RAV-7 infected chicks revealed evidence of lymphoid organ involution and widespread lymphoproliferative lesions by 3 weeks of age. The combination of decreased in vitro lymphoid blastogenesis and in vivo lymphoproliferation suggests that RAV-7 interacts with lymphocytes in a fashion that has not previously been described in the chicken.

Detection of Trichinella infection in food animals.

The first part of this review article deals with classical methods used for the detection of Trichinella larvae in muscle samples of those animal species which are recognized as traditional sources of trichinellosis for human beings, as well as those species which are important for epidemiological reasons. Special consideration is given to the main applications of these methods (routine slaughter inspection, and epidemiological studies in reservoir animals), and to the major factors that may influence detection methods (sampling site, sample size). Historical, current and future aspects concerning national and EU legislation for Trichinella inspection are also presented. The latter part of this review is directed at serodiagnostic methods for the detection of Trichinella-specific antibodies in different animal species. Classical methods of serodiagnosis such as the complement fixation test and immunofluorescence antibody test are reviewed and the characteristics and performance of the ELISA are discussed. Factors dependent upon the animal species being tested or on components of the ELISA test system are considered. This paper also reviews systematic development of the ELISA in relation to improvements in test specificity and sensitivity. Additionally, remarks are made on implementing this test for surveillance and control programs in domestic pigs and wildlife.

Marker enzymes of Plasmodium falciparum and human erythrocytes as indicators of parasite purity.

Plasmodium falciparum trophozoites, isolated by mechanical rupture of infected human erythrocytes, were analyzed for purity by determination of the specific activities of a number of marker enzymes selected for high activity, stability, and convenience of assay procedures. The specific activities of the soluble enzymes lactate dehydrogenase and malate dehydrogenase were much higher in the parasite than in the erythrocyte. The soluble enzyme glutamate dehydrogenase (NADP+) was specific for the parasite. Samples of 100,000 g supernate obtained from parasites that appeared to be free from contaminating erythrocytes consistently showed specific activities of about 4, 3 and 0.1 mumole/min/mg for lactate dehydrogenase, malate dehydrogenase and glutamate dehydrogenase, respectively. Moreover, preparations of parasites that exhibit these specific activities showed low acetylcholine esterase activity in the membrane fractions. The specific activities of these soluble marker enzymes did not appear to be strain dependent. A preparation of highly purified trophozoites obtained by free flow electrophoresis and analyzed for purity by electron microscopy exhibited the same specific activities for these marker enzymes. The use of specific activities of selected marker enzymes should be very useful for determining the purity of preparation of parasites when used in conjunction with other methods.

Aspects of clinical features, diagnosis, notification and tracing back referring to Trichinella outbreaks in north Rhine-Westphalia, Germany, 1998.

52 cases of human trichinellosis were notified from 11 towns in North Rhine-Westphalia from November 1998 to March 1999. After non-typical symptoms in the enteral phase, fever, muscular ache, headache, oedema, disorder of vision and rash occurred in the parenteral phase. Trichinellosis was serologically confirmed by ELISA, IFAT or western blot. Raw sausage and minced meat produced from raw pork could be determined as probable source of infection with 44 and eight notified cases, respectively. Whereas questionable raw sausage was not available for examination, frozen minced meat from the second outbreak could be secured in households of infected people. Larvae were isolated from minced meat and were identified by PCR as Trichinella spiralis. Tracing back to the source of infection was difficult because of the long time between clinical symptoms, laboratory diagnosis and notification as well as complex trade routes for pork and its products. Trichinella cases emphasize the necessity to meet the prescribed slaughter inspection and to guarantee a reliable prove of origin for meat products especially in view of specific consumer habits, i.e. the consumption of raw meat.

Experimental ELISA for diagnosis of ovine dicrocoeliosis and application in a field survey.

Dicrocoeliosis is a parasitic disease caused by trematodes belonging to the genus Dicrocoelium. It usually produces mild symptoms, and for this reason, dicrocoeliosis often remains undetected. Its diagnosis is mostly based on postmortem examination of the liver or on coprological assays for in vivo diagnosis. However, the latter method has scant sensitivity and because of the long pre-patency of Dicrocoelium spp. only permits late diagnosis. In the present study, an enzyme-linked immunosorbent assay (ELISA) was developed based on excretory/secretory antigen of Dicrocoelium dendriticum. The ELISA detected antibodies (IgG) in experimental infected sheep starting from day 30 post-infection (d.p.i.), whereas coprological samples were positive from 58 d.p.i. The ELISA was used in a field study in order to assess dicrocoeliosis seroprevalence in ovine flocks from the province of Trento (northeastern Italy), and this was the first sero-epidemiological study of ovine dicrocoeliosis in northern Italy. Altogether, 842 sheep sera were tested. In accordance with previous surveys carried out in other regions of Italy, a high prevalence of 80% to 100% was found.

[Changes in the perception of risk factors for stroke in the German population between 1995-1996 and 2000-2001. Results of two representative EMNID surveys]. / Veränderungen in der Wahrnehmung der Risikofaktoren für einen Schlaganfall in der deutschen Bevölkerung zwischen 1995/1996 und 2000/2001. Ergebnisse zweier repräsentativer EMNID-Befragungen.

BACKGROUND AND OBJECTIVE: Stroke is one of the leading causes for death and disability worldwide. A better understanding of the perception of modifiable stroke risk factors in the population is the first step to initiate effective prevention strategies on population level. Changes over 5 years in the risk perception in the general population were investigated by two representative surveys in Germany. METHODS: Nationwide programs to screen voluntary participants for stroke risk were undertaken in 1995-1996 and 2000-2001 by the German Stroke Foundation, in cooperation with the health insurance company BARMER and the Sanofi-Synthelabo Company. As part of these programmes two surveys were performed by TNS-EMNID to collect data on population knowledge. A representative sample of the German population was selected and asked to categorize their perception of stroke risk for common vascular risk factors. RESULTS: A total of 8193 participants were interviewed (4081 in 1995-1996 and 4112 in 2000-2001); 43.5% were (3) 50 years of age and 52.5% were female. Hypertension was rated by 68.3% to be in the highest risk category for stroke, followed by smoking (52.3%), hypercholesterolemia (48.0%), overweight (48.0%), excessive alcohol consumption (32.9%) and diabetes (26.6%). The proportion of participants who graded these factors to be important for stroke occurrence was persistently higher in 2000-2001 than in 1995-1996. CONCLUSION: Perception of modifiable risk factors for stroke increased over a 5-year time period in two representative surveys in Germany. The importance of diabetes mellitus as a risk factor for stroke is especially underestimated in the general population.

[Differences in the extent of diagnostic procedures after acute stroke in patients treated in departments of neurology, internal medicine and geriatric medicine]. / Art und Umfang der Diagnostik bei der Akutbehandlung von Schlaganfallpatienten in neurologischen, internistischen und geriatrischen Abteilungen.

BACKGROUND AND PURPOSE: In Germany, data about variations in acute stroke treatment between different facilities are lacking. The aim of the present study was to compare the extent of diagnostic procedures for acute stroke between departments of neurology, internal medicine, and geriatric medicine. METHODS: Stroke patients admitted to hospitals cooperating within the Westphalian Stroke Register between January 1, 2000 and December 31, 2001 were analyzed. Forty-two hospitals participated in the study including 24 departments of neurology, 13 of internal medicine, and 5 of geriatric medicine. The register is based on a standardized data assessment including sociodemographic and clinical characteristics of the patient, in the acute phase, as well as diagnostic and treatment procedures, complications, and status at discharge. The performance of brain imaging, Doppler, and echocardiography was defined as diagnostic standard for diagnosis and etiological classification of ischemic stroke. RESULTS: A total of 12,232 stroke patients were included. Mean age was 72 years, 49 % were men. In general, diagnostic procedures were administered more often in neurological departments compared to departments of internal or geriatric medicine. In all participating hospitals, the application of diagnostic techniques was less frequent in older patients. The defined diagnostic standard was performed more often in those neurological departments providing acute stroke unit services compared to neurological departments without stroke unit services. CONCLUSION: Our study detected variations in the extent of diagnostic procedures in acute stroke between different medical disciplines. However, further studies are required to clarify whether a more frequent performance of diagnostic techniques yields relevant therapeutic consequences.

On-line analysis of electrolytes in extracorporeally circulating blood: application of a rat model to examine the effect of a single pharmacological dose of melatonin on electrolyte levels in blood.

An experimental model was developed to study the kinetics of electrolytes under different physiological and/or pathological conditions. The model was applied to investigate in vivo the effect of a pharmacological dose of melatonin on the concentrations of Ca2+, K+, Na+, and pH in the anticoagulated blood of anaesthetized male Wistar rats (250-350 g). After the application of 0.25 mg melatonin/kg body weight, injected intraperitoneally into each of 8 rats, the electrolytes were measured by a flow-through system with highly sensitive ion-selective electrodes. The results were compared to a control group (n=8) which was treated with diluent (saline). The electrolytes were monitored continuously via an extracorporeal circulation, on-going for at least 60 min. Melatonin induced a significant increase of blood Ca2+ (p<0.02) by an average of 9.9% after 60 min. However, total calcium concentration did not increase significantly. The extracorporeal circulation provoked an elevation of K+ by hemolysis. This K+ increase was slightly diminished by melatonin (p<0.06). No melatonin effects were seen on Na+, pH and magnesium in blood and plasma, respectively. Also, the urine concentrations of the electrolytes were not altered by melatonin. The mechanism by which melatonin influences the blood concentrations of ionized calcium and potassium is not yet understood.

[Chronic recurrent abdominal pain--significance and success of laparoscopic/pelviscopic adhesiolysis]. / Chronisch rezidivierende abdominale Beschwerden--Bedeutung und Erfolge der laparoskopischen/pelviskopischen Adhäsiolyse.

The report is given about 154 patients, who were operated because of chronic abdominal pain in the lower abdomen 27 (17.5%), suspicion of adhesion 43 (27.9%), of an adnexal tumor 56 (33.8%), of endometriosis 5 (3.2%), sterility 11 (10%), or irreversible contraception 16 (7.2%). 112 patients had to be laparotomized once or several times. 105 women had only adhesion; adhesion and an adnexal tumor were found in 27 patients, 22 women had adhesion and endometriosis. Predominant were adhesions of second graduation, 72 women had these adhesions, nine of 105 patients had adhesions of first graduation, adhesions of third graduation had 24 patients. In the last group there was the greatest number of laparotomies. 95 patients answered the questionnaires six months later. 35 (36.8%) were free from pain, 13 (13.8%) stated a clear improvement, 38 (40%) were temporarily free from pain, and 9 (8.2%) stated unchanged pain. One woman complained postoperatively about clear aggravation of pain.

Continuous analysis in extracorporeally circulating blood--a rat model applying flow-through ion-selective electrodes for the measurement of Ca2+, K+, Na+ and pH.

A rat model is introduced which enables investigations in anticoagulated blood with continuous measurements by a flow-through electrode system. In the present study, a potentiometric ion-selective electrode (ISE)-system was used for measuring Ca2+, K+, Na+ and pH in rats. The setup was adjusted to an extracorporeal blood-volume of 0.750 ml. This permits indirect measurements of the analytes via a dialysis membrane, with electrical separation of the ISE's and the animal. The flow-rates of blood and dialysis-solution were adjusted in such a way that water diffusing from the aqueous dialysis solution into the blood, across the dialysis membrane, does not alter the haematocrit. Polyethyleneglycol-hirudin was used for anticoagulation, since it was superior to heparin. The assembly enables continuous measurements in the living anaesthetized rat over a time period of at least 3 hours.