Defects in osmoregulation of vasopressin secretion. A report of four cases

Four patients are presented, all having pathologic responses in plasma vasopressin concentration to changes in plasma osmolality. Clinically, three of them had the syndrome of inappropriate antidiuretic hormone secretion (SIADH). The fourth had diabetes insipidus associated with an increased threshold for plasma osmolality. Two of the patients with SIADH had lowered thresholds for ADH secretion and one of these also had increased sensitivity to increments in osmolality. The latter patient, like another earlier reported similar case, had a defective blood-cerebrospinal fluid barrier. The third SIADH patient had no response at all to changes in osmolality from 230 to 305 mOsm/kg and had a small cell carcinoma of the lung. These examples illustrate that both the setting and the sensitivity of osmoreceptors and AVP-secreting neurons probably are under complex control from the CNS, and that CNS diseases can affect one or several of these pathways thereby affecting the setting of the osmoreceptor-vasopressin system.

Plasma vasopressin, cortisol, and growth hormone concentrations in relation to surgery in the suprasellar region

Posterior and anterior pituitary functions were assessed in 8 patients before, during, and after surgery for tumors in the suprasellar region. Preoperatively, all patients but one responded adequately to an osmotic stimulus with a rise in plasma vasopressin (AVP) and all but one showed adequate cortisol response to adrenocorticotropic hormone (ACTH) and hypoglycemia. During surgery a transient rise was seen in plasma levels of AVP (5 out of 8 patients), cortisol (7 out of 8 patients) and growth hormone (4 out of 8 patients). This response could be predicted from the preoperative stimulation tests. Postoperatively the AVP response to osmotic stimuli was impaired in 4 out of 5 patients, although urine volume had returned to normal after a transient polyuric phase. The response of plasma cortisol to ACTH was still adequate but lower than preoperatively.

The adrenocortical response to angiotensin II infusion in anephric and non-nephrectomized patients on regular hemodialysis

In the present study 8 anephric and 4 non-nephrectomized patients were stimulated with angiotensin II (A-II). In 5 of the anephric patients, an increased plasma aldosterone concentration (PAC) in response to ACTH stimulation had previously been demonstrated. After A-II stimulation, all 8 anephric patients responded with a significant rise in PAC although the increase was less pronounced than in 4 non-nephrectomized patients. In both groups of patients the increase in PAC was correlated to the increase in diastolic and systolic BP and to the A-II dose. Furthermore, in the non-nephrectomized patients, the plasma renin activity showed a significant decline, which was inversely correlated to the increase in PAC. When all 12 patients, regardless of the difference in remaining renin-angiotensin system, were considered as one population, the variable basal levels of PAC correlated significantly to the increase in PAC during A-II and ACTH stimulation. It is concluded that the adrenals of anephric man respond to A-II with an increase in PAC and that the reason for a lower response appears to be the lack of the renin-angiotensin system.

[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.

Retinal vessel oximetry-calibration, compensation for vessel diameter and fundus pigmentation, and reproducibility

The purpose of this study was to measure the hemoglobin oxygenation in retinal vessels and to evaluate the sensitivity and reproducibility of the measurement. Using a fundus camera equipped with a special dual wavelength transmission filter and a color charge-coupled device camera, two monochromatic fundus images at 548 and 610 nm were recorded simultaneously. The optical densities of retinal vessels for both wavelengths and their ratio, which is known to be proportional to the oxygen saturation, were calculated. From 50-deg images, the used semiautomatic vessel recognition and tracking algorithm recognized and measured vessels of 100 microm or more in diameter. On average, arterial and venous oxygen saturations were measured at 98+/-10.1% and 65+/-11.7%, respectively. For measurements in the same vessel segments from the five images per subject, standard deviations of 2.52% and 3.25% oxygen saturation were found in arteries and veins, respectively. Respiration of 100% oxygen increased the mean arterial and venous oxygen saturation by 2% and 7% respectively. A simple system for noninvasive optical oximetry, consisting of a special filter in a fundus camera and software, was introduced. It is able to measure the oxygen saturation in retinal branch vessels with reproducibility and sensitivity suitable for clinical investigations.

Intrinsic tissue fluorescence in an organotypic perfusion culture of the porcine ocular fundus exposed to blue light and free radicals

BACKGROUND

A wide variety of pathological pathways may result in age-related macular degeneration. Because of its complexity, there is no comprehensive model of the disease yet. One key feature is the accumulation of the autofluorescent pigment lipofuscin in the retinal pigment epithelium (RPE). Thus, we developed an organotypic perfusion culture model of the porcine ocular fundus, generating lipofuscin under exposure to blue light and hydrogen peroxide.

METHODS

Porcine fundi (choroid, Bruch's membrane, RPE, and retina) were explanted in toto, transferred into a perfusion culture chamber, perfused with cell culture medium and kept at 37 degrees C. Free radical stress was induced by supplementation of H(2)O(2), and/or the specimens were exposed to blue light, or kept untreated as controls. After a culture period of 7 days, the specimens were subject to microscopic inspection, histology, fluorescence microscopy, and measurement of fluorescence spectra as well as fluorescence decay times.

RESULTS

Histology showed atrophic ganglion cells and rod outer segments. All other tissue structures were morphologically intact. Compared to the controls, RPE and retina exposed to light showed increased fluorescence, which was shifted towards shorter wavelengths. The fluorescence spectra and decays resembled that of lipofuscin granules isolated from human donor eyes. HPLC analysis revealed the abundance of the lipofuscin component N-retinylidene-N-retinylethanolamine (A2E), its precursor products, as well as two new, green-emitting fluorophores.

CONCLUSIONS

Porcine ocular fundi were successfully preserved in an organotypic perfusion culture for 7 days, and exhibited remarkable autofluorescence after light and free radical exposure, making the model suitable for investigations of lipofuscinogenesis.

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.

Ocular fundus auto-fluorescence observations at different wavelengths in patients with age-related macular degeneration and diabetic retinopathy

BACKGROUND

Post-translational protein modification by lipid peroxidation products or glycation is a feature of aging as well as pathologic processes in postmitotic cells at the ocular fundus exposed to an oxidative environment. The accumulation of modified proteins such as those found in lipofuscin and advanced glycation end products (AGEs) contribute greatly to the fundus auto-fluorescence. The distinct fluorescence spectra of lipofuscin and AGE enable their differentiation in multispectral fundus fluorescence imaging.

METHOD

A dual-centre consecutive case series of 78 pseudo-phacic patients is reported. Digital colour fundus photographs as well as auto-fluorescence images were taken from 33 patients with age related macular degeneration (AMD), 13 patients with diabetic retinopathy (RD), or from 32 cases without pathologic findings (controls). Fluorescence was excited at 475-515 nm or 476-604 nm and recorded in the emission bands 530-675 nm or 675-715 nm, respectively. Fluorescence images excited at 475-515 nm were taken by a colour CCD-camera (colour-fluorescence imaging) enabling the separate recording of green and red fluorescence. The ratio of green versus red fluorescence was calculated within a representative region of each image.

RESULTS

The 530-675 nm auto-fluorescence in AMD patients was dominated by the red emission (green vs. red ratio, g/r = 0.861). In comparison, the fluorescence of the diabetics was green-shifted (g/r = 0.946; controls: g/r = 0.869). Atrophic areas (geographic atrophy, laser scars) showed massive hypo-fluorescence in both emission bands. Hyper-fluorescent drusen and exudates, unobtrusive in the colour fundus images as well as in the fluorescence images with emission >667 nm, showed an impressive green-shift in the colour-fluorescence image.

CONCLUSIONS

Lipofuscin is the dominant fluorophore at long wavelengths (>675 nm or red channel of the colour fluorescence image). In the green spectral region, we found an additional emission of collagen and elastin (optic disc, sclera) as well as deposits in drusen and exudates. The green shift of the auto-fluorescence in RD may be a hint of increased AGE concentrations.

[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.

Retinal pigment epithelium cell damage by A2-E and its photo-derivatives

PURPOSE

A2-E, a major component of the retinal pigment epithelium (RPE) lipofuscin, is a compound that can neither be degraded by nor eliminated from cells and is toxic as well as phototoxic to the cells. Illumination of A2-E with short wavelength light results in isomerization, photooxidation, as well as photolysis. Cytotoxic intermediates (free oxygen radicals) and reaction products (peroxides) are involved in this process.

METHODS

A2-E solution (1.28 mM in ethanol or 10 microM phosphate-buffered saline) was kept in dark, exposed to blue light (450-490 nm, 0.2 mW/mm2) for 15 min, or to white light (8.9 mW/mm2) for 60 min, respectively and supplemented to the culture medium of primary porcine RPE cells for 24 h. Damaged cells were determined by staining with propidium iodide in 24 experiments. The photooxidation products of A2-E were analyzed by ultraviolet-visible spectroscopy and MALDI-TOF mass spectrometry.

RESULTS

Supplementation of A2-E for 24 h resulted in a rate of damaged cells of 28%. Blue light exposure of A2-E before supplementation increased the rate to 91% whereas the exposure to high dosage white light reduced it to 14%. Irradiation of A2-E resulted in a dosage-dependent addition of one through four oxygen atoms.

CONCLUSIONS

The increase of the cell damage rate by A2-E irradiated with low dosage light supports the hypothesis of direct DNA damage by oxidized A2-E. Furthermore, we found a reduced cell damage rate from intensively irradiated A2-E resulting in a tetraoxidized molecule which was rather stable and thus less toxic.