[Influence of two different cameras on the spectrometric measurement of oxygen saturation]

OBJECTIVES

Oxygen saturation in retinal vessels can be measured by spectrometry. However, there are no studies on the influence of different camera chips on these measurements. The presented study reports the effect of two different camera chips ("1-CCD" vs. "3-CCD") on the spectrometric measurements in the same patients.

METHODS

61 eyes of 61 patients were included in this study. The study was approved by the local ethics commission. Patients were separated in 3 groups: the first group contained healthy volunteers, the second group patients with diabetes mellitus but without previous laser treatment, the third group included patients with diabetes mellitus and previous laser coagulation treatment. The oxygen saturation was calculated from the difference between wavelengths on and right next to the retinal vessel. This methodology uses the different absorption spectra of oxy- and deoxyhaemoglobin.

RESULTS

All 3 groups demonstrated valid outcomes of the retinal oxygen saturation in arterial and venous vessels. No significant differences we found in the arterial-venous oxygen difference between the two different camera chips (group 1 p = 0.063, group 2 p = 0.204, group 3 p = 0.059).

CONCLUSION

As no significant differences could be found between the two camera chips, the less expensive system should be used if the spectrometric measurement of oxygen saturation is added to an analysis system already established on the market.

Management of severe hypoglycaemia: cultural similarities, differences and resource consumption in three European countries

BACKGROUND

To investigate the characteristics of people with insulin-treated diabetes, who have experienced severe hypoglycaemic events (SHEs), in Germany, Spain or UK.

METHODS

Patients with type 1 (n=319) or insulin-treated type 2 diabetes (n=320) who had experienced ≥ 1 SHE in the preceding year were enrolled. Their median age was 53 years (range, 16-94 years). Data were collected using a questionnaire administered by an experienced interviewer.

RESULTS

The median number of reported SHEs was 2-3 in 12 months. Most events (69%) occurred at home, usually during the day or evening (74%) and most commonly due to insufficient food consumption (45%). In patients whose hypoglycaemia awareness was tested, 68% had normal awareness. Patients requiring emergency healthcare treatment frequently had impaired hypoglycaemia awareness, and developed hypoglycaemic coma more often. Hospital treatment was usually provided in an emergency department (72-94%). The duration of stay was longest in Germany. Following a SHE, patients receiving professional treatment were more likely to: consult their physician, test their blood glucose more often, adjust insulin dose and receive self-management training.

CONCLUSIONS

This survey of diabetes patients aged 16-94 years showed that SHEs represent a substantial burden on national healthcare systems in Germany, UK and Spain. The pattern of occurrence and treatment was similar in all three countries, despite differences in cultures and healthcare systems.

Quantitative assessment of optic nerve head pallor

Ischaemia, loss of neural tissue, glial cell activation and tissue remodelling are symptoms of anterior ischaemic as well as glaucomatous optic neuropathy leading to pallor of the optic nerve head. Here, we describe a simple method for the pallor measurement using a fundus camera equipped with a colour CCD camera and a special dual bandpass filter. The reproducibility of the determined mean pallor value was 11.7% (coefficient of variation for repeated measurements in the same subject); the variation over six healthy subjects was 14.8%. A significant difference between the mean pallor of an atrophic disc and that of the contralateral eye of the same individual was found. However, even the clinically unaffected eye showed a significantly increased pallor compared to the mean of the healthy control group. Thus, optic disc pallor measurement, as described here, may be helpful in the early detection and follow-up of optic neuropathy.

Towards metabolic mapping of the human retina

Functional alterations are first signs of a starting pathological process. A device that measures parameter for the characterization of the metabolism at the human eye-ground would be a helpful tool for early diagnostics in stages when alterations are yet reversible. Measurements of blood flow and of oxygen saturation are necessary but not sufficient. The new technique of auto-fluorescence lifetime measurement (FLIM) opens in combination with selected excitation and emission ranges the possibility for metabolic mapping. FLIM not only adds an additional discrimination parameter to distinguish different fluorophores but also resolves different quenching states of the same fluorophore. Because of its high sensitivity and high temporal resolution, its capability to resolve multi-exponential decay functions, and its easy combination with laser scanner ophthalmoscopy, multi-dimensional time-correlated single photon counting was used for fundus imaging. An optimized set up for in vivo lifetime measurements at the human eye-ground will be explained. In this, the fundus fluorescence is excited at 446 or 468 nm and the time-resolved autofluorescence is detected in two spectral ranges between 510 and 560 nm as well as between 560 and 700 nm simultaneously. Exciting the fundus at 446 nm, several fluorescence maxima of lifetime t1 were detected between 100 and 220 ps in lifetime histograms of 40 degrees fundus images. In contrast, excitation at 468 nm results in a single maximum of lifetime t1 = 190 +/- 16 ps. Several fundus layers contribute to the fluorescence intensity in the short-wave emission range 510-560 nm. In contrast, the fluorescence intensity in the long-wave emission range between 560 and 700 nm is dominated by the fluorescence of lipofuscin in the retinal pigment epithelium. Comparing the lateral distribution of parameters of a tri-exponential model function in lifetime images of the fundus with the layered anatomical fundus structure, the shortest component (t1 = 190 ps) originates from the retinal pigment epithelium and the second lifetime (t2 = 1,000 ps) from the neural retina. The lifetime t3 approximately 5.5 ns might be influenced by the long decay of the fluorescence in the crystalline lens. In vitro analysis of the spectral properties of expected fluorophores under the condition of the living eye lightens the interpretation of in vivo measurements. Taking into account the transmission of the ocular media, the excitation of NADH is unlikely at the fundus.

[Change of retinal oxygen saturation in healthy subjects and in early stages of diabetic retinopathy during breathing of 100% oxygen]

BACKGROUND

Disturbances in the microcirculation are a source of retinal diabetic alterations. Comprehensive studies of blood flow parameters have been performed, but it is not known how ageing, duration of diabetes, blood sugar, glycolysed haemoglobin and elevated systemic blood pressure act in the early stages of diabetic retinopathy.

MATERIAL AND METHODS

The arterial and venous oxygen saturation (aOS, vOS) were measured with a Jena Ophthalmo Spectrometer in 28 healthy subjects (NP) (30.3 +/- 13.1 years), 31 Type I diabetics (T I) (42.2 +/- 12.9 years), and in 25 Type II diabetics (T II) (58.9 +/- 6.9 years), suffering form mild or moderate non-proliferative diabetic retinopathy, before, during breathing of 100 % oxygen for 6 minutes, and after respiration of air during 10 minutes.

RESULTS

Before oxygen breathing, the venous oxygen saturation in diabetics increased with age. During breathing of 100 % oxygen, the vOS increased considerably by 20 % in all groups. The arterio-venous difference of oxygen saturation was decreased with age in diabetics, but there was no dependence on age in normals. In Type II diabetics, the vOS before oxygen breathing was increased with HbA1c. There was also a positive correlation between vOS and blood pressure before oxygen breathing.

CONCLUSION

Healthy subjects and diabetics in the early stages of diabetic retinopathy exhibit comparable changes of oxygen saturation during breathing of 100 % oxygen. Measurements of venous OS are most evident. First differences were detectable between diabetics and normals in the normalisation after oxygen respiration.

[A coping with Stress Training (SBT) for persons with mental illness--pilot study on a group training programme in support of occupational rehabilitation]

OBJECTIVE

This pilot study investigates the effects of a coping with stress training (SBT) programme which had been offered in the Workshop for Disabled People of the Stuttgart Occupational Rehabilitation Center Rudolf-Sophien-Stift to persons with mental illness. The group training is aimed at supporting the participants in coping effectively with stress, avoiding over- or under-stimulation and strengthening positive experiences.

METHOD

In a control-group study design, data was collected from 19 participants of the training group and 11 participants of a (waiting) control group. Data collection was carried out before and after the training.

RESULTS

In the pre-post comparison the training group shows a reduction of symptoms in general and especially in somatization, obsessive-compulsiveness, anxiety, and paranoid ideation. The participants showed improvements in quality of life in the areas of capability, ability to enjoy and relax, positive and negative mood. In respect of attitudes of competence and control they showed improvements in internal control attitudes. Also, as regards illness coping and prevalent coping styles, active and problem-oriented coping styles were found to have increased to some extent. In the problem solving training, 84.2% of the participants stated in their self-ratings that they had been able to achieve positive changes in a specific problem area.

CONCLUSIONS

From a methodological angle it has to be pointed out that the study had examined a very small group. Although a number of open questions remain the results obtained are encouraging and in accordance with the objectives of the training. Further studies need to be carried out with larger samples from different facilities in the fields of medical, vocational and social rehabilitation.

A tool to evaluate the fertiliser value and the environmental impact of substrates from wastewater treatment

Fertilisers may contain pollutants that are applied to the field together with the nutrients. Comparing fertilisers is difficult because of their different concentrations of nutrients and pollutants. In this study an already existing model was taken. It was further developed to compare nutrient fluxes (N, P, K, Ca, Mg, S, humus) and pollutants (heavy metals and pharmaceuticals) of pig and cattle slurry as well as human urine. The data used is taken from literature and, in the case of pharmaceuticals in urine, daily excretion rates were calculated. An amount of 19 m3 ha(-1) a(-1) undiluted urine can be applied, limiting factor is sulphur. Without taking over-fertilisation into account, an addition of mineral fertiliser is required to any organic fertiliser application. In general, heavy metal, antibiotic, and hormone fluxes are higher by using animal manure then urine as fertiliser. However, additional loads of other pharmaceuticals consumed by humans have to be considered. Overall, the model is a suitable tool worthwhile to be extended in aspects of hygiene, environmental impacts as for example, degradation processes as well as ecotoxicology.

Comparing 10-day and 4-month doxycycline courses for treatment of Chlamydia trachomatis-reactive arthritis: a prospective, double-blind trial

OBJECTIVE

To compare the efficacy of a 10-day and a 4-month doxycylcine course for the treatment of Chlamydia trachomatis-reactive arthritis (Ct-ReA).

METHODS

Patients with active Ct-ReA were enrolled in a prospective, multicentre, double-blind, controlled clinical trial and randomised to receive doxycycline 100 mg twice daily for 10 days followed either by placebo or by continued doxycycline 100 mg twice daily over 4 months. Various clinical and laboratory parameters referring to disease activity were recorded in the beginning and at the end of treatment.

RESULTS

32 of 37 patients included (15 men and 17 women; mean (standard deviation) disease duration 17 (13) months completed the study; 17 were randomised to short-term doxycycline and placebo (placebo group) and 15 to prolonged treatment with doxycycline (doxycycline group) over the 4-month study period. After this time, only two patients from each group went into remission. There were no drop-outs owing to adverse events or treatment failures.

CONCLUSIONS

The results of this study suggest that prolonged treatment with a 4-month course of doxycycline is not superior to short-term treatment over 10 days in patients with Ct-ReA.

Efficacy of sulfasalazine in patients with inflammatory back pain due to undifferentiated spondyloarthritis and early ankylosing spondylitis: a multicentre randomised controlled trial

OBJECTIVES

To assess the effect of sulfasalazine (SSZ) on inflammatory back pain (IBP) due to active undifferentiated spondyloarthritis (uSpA) or ankylosing spondylitis in patients with symptom duration <5 years.

METHODS

Patients with IBP and a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) >3 from 12 centres were randomly assigned to 24 weeks' treatment with SSZ 2 g/day or placebo. The primary outcome variable was the change in BASDAI over 6 months. Secondary outcomes included measures of spinal pain, physical function and inflammation.

RESULTS

230 patients (50% men, age range 18-64 years, 67% human leucocyte antigen B27 positive) were treated with either SSZ 2x1 g/day or placebo for 6 months. Enthesitis was found in 50%, and peripheral arthritis in 47% of the patients. The mean (SD) BASDAI dropped markedly in both groups: by 3.7 (2.7) and 3.8 (2.4), respectively, as did most secondary outcome measures. No noticeable difference in treatment was observed between groups. Patients with IBP and no peripheral arthritis had significantly (p = 0.03) more benefit with SSZ (BASDAI 5.1 (1.3) to 2.8 (2.3)) than with placebo (5.2 (1.6) to 3.8 (2.4)). Spinal pain (p = 0.03) and morning stiffness (p = 0.05) improved with SSZ in these patients, but other secondary outcomes were not markedly different.

CONCLUSION

SSZ was no better than placebo for the treatment of the signs and symptoms of uSpA; however, SSZ was more effective than placebo in the subgroup of patients with IBP and no peripheral arthritis.

Induction of pre-transplant Epstein-Barr virus (EBV) infection by donor blood transfusion in EBV-seronegative recipients may reduce risk of post-transplant lymphoproliferative disease in adolescent renal transplant patients: report of two cases

BACKGROUND

Post-transplant lymphoproliferative disease (PTLD) is a life-threatening complication following organ transplantation. The greatest risk is seen in Epstein-Barr virus (EBV)-seronegative patients receiving allografts from EBV-seropositive donors. We demonstrate a new approach of pre-transplant prophylaxis of EBV-related PTLD, suggesting that, prior to living-related renal transplantation, blood transfusion from an EBV-seropositive donor to an EBV-seronegative recipient could induce primary EBV infection in the recipient, developing EBV immunity and decreasing risk of PTLD.

METHODS

Recipients underwent weekly donor-specific blood transfusion (3 x 100 mL) before transplantation. EBV-mRNA expression, viral load, serological tests, and clinical signs of EBV infection were assessed following blood transfusion.

RESULTS

We explored a new approach in 2 young EBV-seronegative renal allograft recipients. Both patients developed primary EBV infection following blood transfusion before transplantation and showed symptom-free seroconversion post-transplantation without persistent EBV activation. There were no signs of PTLD during 5-year follow-up.

CONCLUSIONS

A new effective and inexpensive approach is suggested for development of EBV immunity and probably for prophylaxis of EBV-associated PTLD.

Fundusspektrometrie bei altersbezogener Makulopathie

BACKGROUND

Spectroscopic methods permit the non-invasive detection of fundus pigments by the wavelength-dependent absorption of fluorescence as well as by the fluorescence lifetime. From the relative concentrations of haemoglobin and oxyhaemoglobin, the oxygen saturation can be calculated. The onset of age-related maculopathy might be delayed by a high optical density of xanthophyll. The detection of alterations in fundus autofluorescence points to age-related pathomechanisms (accumulation of lipofuscin, formation of connective tissue). The detection of autofluorescence of redox-pairs of coenzymes results in information about metabolic states at the cellular level, and might make possible an early detection of age-related changes when they are still reversible.

METHOD

The evaluation of reflectance spectra, detected by imaging ophthalmo-spectrometry, results in the calculation of oxygen saturation or in the optical density of xanthophyll or of melanin. Fluorescence spectra can be measured also by this technique. For the 2-dimensional determination of the distribution of xanthophyll, a very simple method was developed, requiring fundus illumination by one wavelength only. In the detection of time-resolved autofluorescence, the fluorescence lifetime is used for the determination of endogenous fluorophores.

RESULTS

As result of comparing studies between ARM patients and healthy subjects, the consumption of retinal oxygen was increased already in the children of ARM patients. An increasing optical density of xanthophyll was determined after lutein supplementation. Differences in fluorescence lifetime were determined between ARM patients and healthy subjects, but their interpretation requires investigations of cell or of organ model cultures.

CONCLUSIONS

The described methods permit in vivo basic investigations of ARM and can be considered as impulses for the development of diagnostic devices.

[Spectral separation in ocular fundus autofluorescence images in patients suffering from age-related macular degeneration]

INTRODUCTION

Alterations in the intrinsic ocular fundus fluorescence are under discussion particularly in connection with age-related macular degeneration. However, further knowledge of the chemical substrate of fluorescence is necessary.

METHOD

Ocular fundus autofluorescence was observed using a fundus camera. The fluorescence emission was recorded using a 3-chip CCD camera. For comparison, the fluorescence spectra of lipofuscin, A2-E, FAD, NADH(2) and AGE's were recorded by the Jena ophthalmo-spectrometer.

RESULTS

In contrast to the homogeneous intrinsic fluorescence of a normal fundus, the fluorescence images of patients suffering from AMD showed remarkable local differences. The detected fluorescence spectra showed remarkable overlaps.

DISCUSSION

We introduced a new technique enabling the detection of spectral differences in images of ocular fundus autofluorescence. Besides the fluorescence of lipofuscin, we found a green one in patients suffering from nonexudative AMD.

Grenzen der konfokalen Laser Scanning Technik bei Messungen der zeitaufgelösten Autofluoreszenz am Augenhintergrund / Limits of the confocal laser-scanning technique in measurements of time-resolved autofluorescence of the eye-ground

GOAL

The 2-dimensional measurement of the time-dependent autofluorescence has in combination of confocal laser scanner technique and time correlated single photon counting the potential for the investigation of the metabolism state at the eye ground. It was to be examined, to what extent these measurements are influenced through the auto-fluorescence of the crystalline lens.

MATERIAL AND METHOD

The time-dependent auto-fluorescence was measured on eyes of 21 patients with age-related macular degeneration (AMD) and of 26 healthy subjects in 40 degrees fundus images. The experimental set-up used, was developed at the eye clinic of the University of Jena. In this scanning laser ophthalmoscope, the fundus was excited at 446 nm by pulses of 100 ps full width at half maximum and 40 MHz repetition rate. The auto-fluorescence was detected with a time resolution of 25 ps for wavelengths > 500 nm. The dynamic auto-fluorescence of each pixel was approximated by a tri-exponential model function. In order to determine the influence of the fluorescence of the crystalline lens, healthy eyes and eyes were compared with implanted artificial intra-ocular lenses. For comparison the frequency distributions were used, which the decay times t1, t2 and t3 in the fundus images had been calculated with.

RESULTS

Clear differences were shown in the frequency distributions of the fluorescence lifetimes between AMD-patients and healthy subjects, It resulted, however, from a crucial analysis that the fluorescence of the crystalline lens is not suppressed by the confocal laser scanning principle sufficiently. In particular the long lifetime t3 is overlapped by the fluorescence of the crystalline lens of about 4.6 ns. To the complete suppression of the influence of the lens fluorescence in measurements of the time-resolved fundus auto-fluorescence it is suggested to combine the confocal laser scanning technique with the principle of the aperture diaphragm division.

CONCLUSION

In order to be able to determine the capability of measurements of the time-dependent fundus auto-fluorescence as diagnostic tool exactly, the influence of the crystalline lens is to reduce through the combination of confocal laser scanning ophthalmoscopy with the principle of the aperture diaphragm division diversely.

Nutzen der station�ren Therapie in der Versorgung von Patienten mit Rheumatoider Arthritis

Our aim was to analyze the existing body of evidence about inpatient care of patients suffering from rheumatoid arthritis (RA). The report was induced by the executive board of the German Society of Rheumatology which assigned the "Oliver-Sangha committee" to dissect and point out the tasks of inpatient care during the next few years. A systemic search of the literature was performed covering the years 1966 to 2001. A total of 16 studies were selected and thoroughly appraised in a systematic way. Four randomized controlled trials addressing the question could be identified. All of them included only patients in a clinical condition allowing outpatient care as well. Two studies indicate some advantage of inpatient care in comparison to outpatient treatment. Two studies, both equivalence studies from design, reveal that RA patients do not generally experience additional benefit from hospitalization. Consideration of two additional cohort studies demonstrates the increased need of inpatient care in RA patients. None of the studies was derived from the German health care system. Emergency cases were not the subject of any of these trials. General statements about the value of inpatient care of RA patients can not be drawn from the analyzed studies. The committee makes suggestions for future investigations that may help to answer this important question considering the special circumstances of the German health care system.

[Alterations in autofluorescence decay time in the fundus after oxygen provocation]

BACKGROUND

Alterations in the equilibrium of redox pairs of co-enzymes give information about the metabolic state in the citric acid cycle as well as in the respiratory chain. Fluorescence properties are different between the reduced and oxidised states of co-enzymes so that a change of the oxygen partial pressure can be sensitively detected in the tissue. Therefore, it was investigated whether the autofluorescence of co-enzymes is detectable in the living fundus.

METHOD

The provocation of metabolism was realised by inspiration of 100% oxygen. The time-resolved autofluorescence was detected by a single photon counting technique. The decay behaviour of autofluorescence was approximated by a bi-exponential model. For evaluation of the results, histograms of decay times tau(1) and tau(2) were calculated in defined ranges around the macula and optic disc before, during, and after inhaling oxygen.

RESULTS

The calculated decay times corresponded in the macula to the decay times of FAD and NADH(+) given in the literature. Connective tissue in the optic disc also showed fluorescence.

CONCLUSIONS

Changes in the histograms of decay rates demonstrate that provocation of metabolism is detectable by measurement of time-resolved autofluorescence. This method reveals the evaluation of metabolism at the cellular level as a new diagnostic possibility.

[Determination of the concentration distribution of macular pigment from reflection and fluorescence images]

OBJECTIVE

The macular pigment xanthophyll protects the macula in two ways: firstly, it absorbs hazardous blue light and secondly, it acts as a radical scavenger. A low concentration of xanthophyll may be regarded as a risk factor for age-related macular degeneration (AMD). Therefore, we investigated a simple method to determine the xanthophyll concentration at the fundus which is suitable for patient screening.

METHOD

The local distribution of xanthophyll density was determined from monochromatic blue reflection images and autofluorescence images of the fundus in 18 healthy volunteers (mean age: 23.9 years). The significance of the parameters maximal, global, and mean concentration were compared.

RESULTS

The maximal optical density of xanthophyll determined from reflection images was found to be 0.29+/-0.08 (mean for all test persons) which is in good agreement with literature data. The total xanthophyll concentration which is proportional to the maximal density, appeared to be appropriate to describe a person's overall xanthophyll status. Because of the low intensity of autofluorescence images, these are less useful for the determination of the xanthophyll concentration.

CONCLUSIONS

Because of it's simplicity, the determination of xanthophyll concentration as described here can be performed by every ophthalmologist using a fundus camera and is, therefore, suitable as a screening method.

[Expert assessment of patients with rheumatoid arthritis]

Rheumatoid arthritis (RA) is the most common inflammatory disease of the locomotor system associated with early loss of function and joint destruction. A relevant number of patients with RA withdraw from employment within the first years. To give a medical opinion on patients with RA regarding ability for work requires thorough knowledge of the disease, its characteristic deformities and prognostic indicators as well as knowledge of the essential examinations and instruments for the estimation of functioning and disability.

[Time-correlated measurement of autofluorescence. A method to detect metabolic changes in the fundus]

The detection of metabolic changes opens the possibility for intervention of reversible pathological alterations. Measurements of oxygen saturation are limited to the blood vessel system. Detection of alterations in oxygen concentrations are up to 3 orders of magnitude more sensitive by autofluorescence of coenzymes than by measurement of oxygen saturation. Because of limited transmission of the ocular media no specific excitation of endogenous fluorophores can be realised. For this reason it was investigated if the fluorescence lifetime after pulse excitation can be detected at the human fundus. Applying a laser scanner ophthalmoscope and mode-locked Ar(+) laser as well as time-correlated single photon counting, lifetime images of the living fundus were obtained. In mono-exponential approximation, a mean lifetime of 5 ns was detected from the optic disc and large vessels whereas about 1.5 ns were detected in the parapapillary area. By evaluating the frequency of lifetimes, lipofuscin, free FAD, and collagen are probably detectable. Comparative measurements were performed in fundus specimens and on free FAD.

[Intrastomal refractive surgery with ultra-short laser pulses. Results from initial in vitro experiments]

PURPOSE

To investigate the possibilities and techniques for intrastromal ablation of the cornea by the use of ultra-short laser pulses.

METHOD

A laser-induced plasma with a diameter of 8 mu was generated 100-300 mu below Bowmans membrane by focussing of a Ti:Saphir laser (lambda=805 nm, pulse width: 115 fs, energy: 0.6-3.3 microJ). Scanning the laser beam enabled arbitrary transsections in the corneal stroma. All experiments were performed in porcine eyes 1-4 h post-mortem.

RESULTS

Two-dimensional sections were achieved applying a minimal laser energy of 0.6 microJ at a separation of the single laser effects of 10 micrometer. A 150 micrometer thick disc was excised 150 micrometer below Bowmans membrane and extracted through a keratotomy performed by the laser. Sharp-cut edges were observed by slit-lamp biomicroscopy.

CONCLUSIONS

Ultra-short laser pulses are suitable for precise intrastromal ablation.

A new method for the measurement of oxygen saturation at the human ocular fundus

Measurements of the transmission and the reflectance spectra of whole blood exhibit a different dependence of the thickness of the blood layer. Whereas the transmission spectra decrease at all wavelengths, in the reflectance two ranges with different behaviour have to distinguish. In the absorption dominated range between about 500 and 600 nm, there is only a marginal influence of the thickness of the blood layer. In contrast, in the scattering dominated range higher than about 600 nm the reflectance increases if the thickness of the blood layer increases. Proofed by Monte Carlo simulation, the reflected light, which will be measured in ophthalmologic devices, consists both of light which penetrates a vessel once and will be reflected at the background and of light which is internally reflected at the blood column. Only in small vessels (diameter < 50 microm) the transmitted part dominates. With increasing diameter of the vessels the internally reflected light dominates. Especially under the conditions of a confocal laser scanner, the transmitted part of light is always small. As the measured light consists of both parts of light, a new model for the approximation of the measured reflected light is given, containing an expression for the transmitted and for the internally reflected light. The model was applied for the approximation of the reflectance of blood in a cuvette with an coloured background, delivering sufficient exact result. The oxygen saturation was determined in 256 measurements of 30 healthy persons using an ophthalmo imaging spectrometer. The mean arterial oxygen saturation was 91 +/- 5%, the mean venous oxygen saturation was 59 +/- 9% and the arterio-venous difference in the oxygen saturation was 35%, which is in good agreement with the arterio-venous difference known in the brain. First measurements of the oxygen saturation in age-related macular degeneration point to partly different pathological changes of the retinal microcirculation in dry and in wet AMD.

Basic investigations for 2-dimensional time-resolved fluorescence measurements at the fundus

The decay time is characteristic for several natural fluorophores. The determination of the decay time is independent of the fluorescence intensity. As a consequence, a short living weak fluorescence should be detectable also if it is covered by a intensive long-living fluorescence. As the decay time is influenced by the embedding matrix, information about the cellular stage might be possible. The laser scanning technique in combination with the time correlated single photon counting technique seems to be the optimal method for the discrimination of different fluorophores at the fundus according to the decay time. Fields of an equal decay time are presented as a tau mapping. An experimental set up was developed. Until now, only basic experiments were done on structured fluorescent tests, but under the conditions of the living eye. The results are promising. For the separate detection of the most important short life-time of 120 ps of A2E (excitation at 413 nm. emission 450-600 nm) as a putative precursor of lipofuscin in age-related macular degeneration [11], a light source for pulses in the range of about 50 ps is required.

Non-invasive measurement of the concentration of melanin, xanthophyll, and hemoglobin in single fundus layers in vivo by fundus reflectometry

A new model of the reflection of the human ocular fundus on the basis of the adding-doubling method, an approximate solution of the radiative transport equation, is described. This model enables the calculation of the concentration of xanthophyll in the retina, of melanin in the retinal pigment epithelium and in the choroid, and of hemoglobin in the choroid from fundus reflectance spectra. The concentration values found in 12 healthy subjects are in excellent agreement with literature data. In single cases of pathologic fundus alterations possible benefits to the ophthalmologic diagnostics is demonstrated.

[Objective determination of optical density of xanthophyll after supplementation of lutein]

BACKGROUND

It is thought that a high optical density of xanthophyll has a protective effect against the development of aggregated macular degeneration. The aim of this study was to investigate whether an increase of the optical density of xanthophyll in the macula after a supplementation of lutein can be proven by objective methods. Most methods applied for the determination of the macular pigment require the co-operation of the proband and the ability for foveal fixation.

METHOD

Imaging spectrometry and the evaluation of laser scanner images taken at 488 nm will be presented. In contrast to psychophysical methods, both methods are independent of the patients ability for foveal fixation.

RESULTS

Even by evaluation of laser scanner images taken as in fluorescence angiography but without inserting the blocking filter, the 2-dimensional distribution of xanthophyll can be determined. In 10 probands taking 6 mg lutein daily over 40 days, an increase of the optical density could be determined at least in some probands. The optical density reached a plateau 30 days after starting the supplementation of lutein.

CONCLUSION

The assumed protective effect of xanthophyll against age-related macular degeneration can be influenced by supplementation of lutein under objective control.

Urinary excretion and bactericidal activities of gemifloxacin and ofloxacin after a single oral dose in healthy volunteers

In a randomized crossover study, 16 volunteers (8 men, 8 women) received single oral doses of 320 mg of gemifloxacin and 400 mg of ofloxacin on two separate occasions in the fasting state to assess the urinary excretion and urinary bactericidal titers (UBTs) at intervals for up to 144 h. Ofloxacin showed higher concentrations in urine compared with those of gemifloxacin. The median (range) cumulative excretion of gemifloxacin was 29.7% (8.4 to 48.7%) of the parent drug administered, and median (range) cumulative excretion of ofloxacin was 84.3% (46.5 to 95.2%) of the parent drug administered. The UBTs, i.e., the highest twofold dilutions (with antibiotic-free urine as the diluent) of urine that were still bactericidal, were determined for a reference strain and nine uropathogens for which the MICs of gemifloxacin and ofloxacin were as follows: Escherichia coli ATCC 25922, 0.016 and 0.06 microg/ml, respectively; Klebsiella pneumoniae, 0.03 and 0.06 microg/ml, respectively; Proteus mirabilis, 0.125 and 0.125 microg/ml, respectively; Escherichia coli, 0.06 and 0.5 microg/ml, respectively; Pseudomonas aeruginosa, 1 and 4 microg/ml, respectively; Staphylococcus aureus, 0.008 and 0.25 microg/ml, respectively; Enterococcus faecalis, 0.06 and 2 microg/ml, respectively; Staphylococcus aureus, 0.25 and 4 microg/ml, respectively; Enterococcus faecalis, 0.5 and 32 microg/ml, respectively; and Staphylococcus aureus, 2 and 32 microg/ml, respectively. Generally, the UBTs for gram-positive uropathogens were higher for gemifloxacin than for ofloxacin and the UBTs for gram-negative uropathogens were higher for ofloxacin than for gemifloxacin. According to the UBTs, ofloxacin-resistant uropathogens (MICs, >or=4 mg/liter) should also be considered gemifloxacin resistant. Although clinical trials have shown that gemifloxacin is effective for the treatment of uncomplicated urinary tract infections, whether an oral dosage of 320 mg of gemifloxacin once daily is also adequate for the treatment of complicated urinary tract infections has yet to be confirmed.

Chlamydia and Borrelia DNA in synovial fluid of patients with early undifferentiated oligoarthritis: results of a prospective study

OBJECTIVE

More than 50% of patients with synovitis involving 1-4 joints remain classified as having undifferentiated oligoarthritis (UOA) after 1 year of disease. The clinical presentation is often similar to that of reactive arthritis (ReA) and other spondylarthropathies or to Lyme arthritis. We therefore determined how often Chlamydia trachomatis (Ct) and Borrelia burgdorferi (Bb) can be identified in patients with UOA, by using an extensive laboratory approach.

METHODS

We prospectively studied 52 patients with UOA who presented at an early synovitis clinic in a region highly endemic for Lyme disease. Patients were examined by standardized clinical and immunoserologic procedures. Synovial fluid was screened for the presence of Ct and Bb DNA by polymerase chain reaction (PCR). Urine was tested for Ct DNA by ligase chain reaction, and serum was tested for Ct antibodies by enzyme-linked immunosorbent assay and Bb antibodies by hemagglutination test and Western blotting. PCR results in the UOA patients were compared with the results in cohorts of patients with definite rheumatoid arthritis (RA), Lyme arthritis, and Chlamydia-induced arthritis (CIA).

RESULTS

In the synovial fluid of 9 of 52 patients with UOA (17%), we found Ct DNA, and in 6 of the 52 patients (12%), Bb DNA was found. The frequency of bacteria-specific DNA was 50% (7 of 14) in CIA patients and 69% (11 of 16) in patients with Lyme arthritis. No Bb or Ct DNA was found in the synovial fluid of the 31 RA patients.

CONCLUSION

With optimized PCR protocols, it is possible to detect considerable levels of Bb and Ct DNA in the synovial fluid of patients with UOA. Although the presence of bacterial DNA does not unequivocally prove its etiologic significance, we suggest that at least one-third of patients with UOA may have a form of ReA that involves asymptomatic primary infection.

The superefficient company

Most companies do a great job promoting efficiency within their own walls, streamlining internal processes wherever possible. But they have less success coordinating cross-company business interactions. When data pass between companies, inconsistencies, errors, and misunderstandings routinely arise, leading to wasted work--for instance, the same sales, order entry, and customer data may be entered repeatedly into different systems. Typically, scores of employees at each company manage these cumbersome interactions. The costs of such inefficiencies are very real and very large. In this article, Michael Hammer outlines the activities and goals used in streamlining cross-company processes. He breaks down the approach into four stages: scoping--identifying the business process for redesign and selecting a partner; organizing--establishing a joint committee to oversee the redesign and convening a design team to implement it; redesigning--taking apart and reassembling the process, with performance goals in mind; and implementing--rolling out the new process and communicating it across the collaborating companies. The author describes how several companies have streamlined their supply-chain and product development processes. Plastics compounder Geon integrated its forecasting and fulfillment processes with those of its main supplier after watching inventories, working capital, and shipping times creep up. General Mills coordinated the delivery of its yogurt with Land O'Lakes; butter and yogurt travel cost effectively in the same trucks to the same stores. Hammer says this new kind of collaboration promises to change the traditional vocabulary of corporate relationships. What if you and I sell different products to the same customer? We're not competitors, but what are we? In the past, we didn't care. Now, we should, the author says.

[The optics of retinal blood vessels and their significance for scanning laser Doppler flowmetry]

Recently, the scanning laser Doppler flowmetry (SLDF) has been developed as a standard method for the quantification of retinal blood flow. However, the measured quantities flow, volume, and velocity depend on the angle between the direction of the blood flow and of the light. The underlying theory assumes isotropic illumination of the vessel. This assumption, however, is not valid for light back-scattered from retinal vessels. This paper investigates the contribution of different pathways of the light to the SLDF signal by a Monte Carlo simulation. It is shown that the light measured on a vessel having a thickness of 50 microns is predominantly back-scattered from the blood inside the vessel, whereas the measurement on vessels 20 microns in diameter or less also includes light transmitted through the vessel.

Formation of strong airway irritants in mixtures of isoprene/ozone and isoprene/ozone/nitrogen dioxide

We evaluated the airway irritation of isoprene, isoprene/ozone, and isoprene/ozone/nitrogen dioxide mixtures using a mouse bioassay, from which we calculated sensory irritation, bronchial constriction, and pulmonary irritation. We observed significant sensory irritation (approximately 50% reduction of mean respiratory rate) by dynamically exposing the mice, over 30 min, to mixtures of isoprene and O3 or isoprene, O3, and NO2. The starting concentrations were approximately 4 ppm O3 and 500 ppm isoprene (+ approximately 4 ppm NO2. The reaction mixtures after approximately 30 sec contained < 0.2 ppm O3. Addition of the effects of the residual reactants and the identified stable irritant products (formaldehyde, formic acid, acetic acid, methacrolein, and methylvinyl ketone) could explain only partially the observed sensory irritation. This suggests that one or more strong airway irritants were formed. It is thus possible that oxidation reactions of common unsaturated compounds may be relevant for indoor air quality.

Transforaminal ventral epidural adhesiolysis

Epidural fibrosis with chronic low back pain, nonresponsive to traditional measures of treatment including surgery, is a common entity in modern medicine. Traditionally, epidural steroid injections have been employed to treat chronic low back pain and radiculopathy associated with failed back surgery. Due to the poor effectiveness of epidural steroid injections in post lumbar laminectomy syndrome, epidural adhesiolysis was introduced in the early 1980s. Caudal epidural adhesiolysis with hypertonic saline neurolysis has been described extensively in the literature and has been proven to be relatively successful and safe. To improve the results and reach the target area with steroid, transforaminal ventral epidural adhesiolysis has been utilized. This retrospective case analysis included 14 patients. Transforaminal ventral epidural adhesiolysis was performed on an outpatient basis in all patients. The results showed 93% improvement initially, which decreased to 71% at 1 month, 57% at 3 months, 43% at 6 months and 21% at 1 year. The results of this case study show that ventral epidural lysis of adhesions with hypertonic saline neurolysis is safe and effective in managing chronic low back and lower extremity pain in patients who failed to respond to other conservative modalities of treatments, including fluoroscopically directed transforaminal epidural steroid injections.

Evidence of T cell clonality in the infectious tolerance pathway: implications toward identification of regulatory T cells

We have shown that a rare population of regulatory CD4+ T cells plays a key role in the acquisition of infectious tolerance in rat sensitized recipients of cardiac allografts pretreated with nondepleting anti-CD4 mAb. This study was designed to analyze the TCR Vbeta expression patterns in this transplantation model. First, we used Vbeta-specific RT-PCR to show that there was no differential usage of TCR Vbeta genes by T cells mediating rejection or tolerance. Indeed, graft-infiltrating lymphocytes expressed most of the 22 known rat TCR Vbeta genes in both recipient groups, suggesting unrestricted TCR Vbeta repertoire in alloreactive T cells. Then, we applied CDR3 spectrotyping of TCR beta-chain to assess the clonality of T cells at different anatomic sites. CDR3 size restriction, indicative of the presence of T cell clones, was observed in graft-infiltrating lymphocytes but not in draining lymph nodes or spleen of tolerant hosts. Consisent with the clonal expansion, T cells in tolerated grafts exhibited the memory phenotype at a much higher percentage as compared with peripheral lymphoid organs. Moreover, in tolerated graft-infiltrating lymphocytes, the CD3 size restriction occurred in limited Vbeta gene families, with Vbeta8.1 and Vbeta18 most frequently detected. Hence, T cells at the graft site of tolerant recipients contain T cell clones expressing selective Vbeta genes. This phenotypic characteristics of the tolerogenic GILs may potentially be used as a novel marker to identify operational regulatory T cells in organ allograft recipients.

Light paths in retinal vessel oxymetry

The oxygen utilization and, therefore, the metabolic state, of a distinctive area of the retina may be calculated from the diameter of the supplying artery and vein, the haemoglobin oxygenation, and the velocity of the blood. The first two parameters can be determined by imaging spectrometry at the patients ocular fundus. However, the reflected light emerging from a vessel followed different pathways through the ocular fundus layers and the vessel embedded in the retina. The contribution of the single pathways to the vessel reflection profile is investigated by a Monte Carlo simulation. Considering retinal vessels with diameters of 25-200 microm we found the reflection from a thin vessel to be determined by the single and double transmission of light at 560 nm. The backscattering from the blood column determines the reflectance in the case of a thick vessel. However, both components are in the same order of magnitude. This has to be considered in the calculation of the oxygen saturation of blood in retinal vessels from their reflection spectra.

A scattering phase function for blood with physiological haematocrit

Though the optics of red blood cells as well as whole blood has been studied extensively, an effective scattering phase function for whole blood is still needed. The interference of waves scattered by neighbouring cells cannot be neglected in highly concentrated suspensions such as whole blood. As a result, the phase function valid for single erythrocytes may fail to describe a single scattering process in whole blood with physiological haematocrit (Hct approximately 0.4). In this study we compared the results obtained in goniophotometric measurements of blood samples with the results of angle-resolved Monte Carlo simulations. The results show that a Henyey-Greenstein phase function with an anisotropy factor of 0.972 is an adequate approximation for the effective scattering phase function of whole blood with high haematocrit at a wavelength of 514 nm.

[Relationship between illness, rehabilitation and work (ZERA)--an training program for medical-vocational rehabilitation of the mentally ill]

A training programme for rehabilitation of people with mental illness is presented, designed particularly for schizophrenic patients who need occupational rehabilitation. The training goal is to connect aspects of the schizophrenic disorder with vocational issues. It is aimed at supporting the participants in developing a realistic and appropriate vocational perspective in line with their illness related restrictions and current vocational possibilities, seeking to find out the individual's optimal ability to take stress so as to avoid over- or understimulation in vocational respects. The ZERA training has been developed for implementation in different medical and vocational rehabilitation settings for persons with mental illness. An initial control-group study was carried out to evaluate the effectiveness of this group training approach, and preliminary results have revealed changes in the experimental group in accordance with the objectives of the training and encourage further research.