High prevalence of ST-78 infection-associated vancomycin-resistant Enterococcus faecium from hospitals in Asunción, Paraguay.

Forty infection-associated VanA-type vancomycin-resistant Enterococcus faecium (VRE) strains obtained from five collaborating hospitals in Asunción, Paraguay were investigated. Genotyping using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing revealed the presence of 17 cluster types and four STs, with 93% (37/40) of isolates comprising ST type 78. Other ST types included ST-132, ST-210 and one new ST type (ST-438). All but one isolate (ST-438) were associated with clonal complex 17 (CC17), and 97% of the total isolates carried the esp gene. Three Tn1546 variants were found, including a new lineage containing an ISEfa5 insertion in an existing IS1251 element.

[Assessment and management of the risk for violence. An overview of the literature]. / Beoordeling en management van het risico op gewelddadig gedrag.

BACKGROUND: In general psychiatry the risk of violence has to be assessed regularly, for instance in cases where civil commitment is under consideration. AIM: This article gives an overview of the actuarial instruments for risk assessment, discusses a model for the clinical assessment of risks of violence and for the compulsory management of such risks. METHOD: The relevant literature was located via cross-references from key publications and via bibliographic references in specialized journals. The key words used in the search were violence, violent behaviour, dangerousness, risk assessment, risk prediction and risk management. RESULTS: Standardised actuarial assessment of the risk of violence is only of limited value in general psychiatric practice. Among certain high-risk groups standardised instruments targeted at the specific type of risk (acute, long-term) and at the type of decision (relating to security, treatment) can have added value within a broader clinical assessment. CONCLUSION: In general psychiatric practice a potential risk of violence should be assessed systematically in a structured manner. If there are risks of violence these can best be studied and assessed in specialised clinics or by specialized teams. Dynamic risk factors and protective factors should be evaluated systematically in cooperation with the various organizations concerned.

[Visual acuity and magnification requirement after ranibizumab in patients with wet age-related macular degeneration]. / Fernvisus und Vergrösserungsbedarf nach Ranibizumab bei Patienten mit feuchter altersbedingter Makuladegeneration.

BACKGROUND: The purpose of this study was to examine the visual outcome by measuring visual acuity (VA) and magnification requirement (MR) in patients with wet AMD after repeated intravitreal injections of ranibizumab. PATIENTS AND METHODS: A total of 195 eyes were treated with repeated intravitreal injections of ranibizumab "as needed". VA (Snellen chart) and MR (SZB reading chart) at baseline of 114 eyes with occult or minimally classic lesions, 42 eyes with predominantly classic lesions and 39 with retinal angiomatous proliferations (RAP) were compared at 3 and 6 months after beginning of treatment. RESULTS: The whole group of 195 patients with wet AMD (688 intravitreal injections within 6 months) demonstrated a mean improvement of VA of 0.72 lines after 3 months (p < 0.001) and 1.54 lines after 6 months (p < 0.001) and a mean improvement of MR of 0.59 log units after 3 months (p < 0.001) and 0.73 log units after 6 months (p < 0.001). Mean change in VA after 3 and 6 months demonstrated a significant improvement (p < 0.001 to p < 0.05) for eyes with occult CNV (+ 0.8 /+ 1.6 lines) and RAP (+ 1.2 /+ 1.9 lines) whereas mean improvement in VA for classic CNV (+ 0.02 /+ 0.87 lines) did not reach significance compared to baseline. Comparable results were obtained for the mean change of MR after 3 and 6 months for eyes with occult CNV (+ 0.75 log units/+ 0.92 log units). For eyes with RAP mean improvement of MR was + 0.74 log units after 3 months (p < 0.05) and it was not significant with + 0.8 log units after 6 months (p > 0.05). MR did not show a significant change during follow-up for classic CNV. Apart from eyes with classic CNV, in more than 90 % of the eyes both VA and MR remained stable or improved (loss < 3 lines in VA or deterioration of MR of < 3 log units). Although 45 % of the eyes with predominantly classic CNV had received photodynamic therapies with Verteporfin prior to the intravitreal injections with ranibizumab, MR remained stable in 80 % over 6 months. CONCLUSION: With repeated injections of ranibizumab "as needed", VA could be improved as well as MR could be lowered in a majority of patients with wet AMD and therefore reading ability could be optimized. Over 6 months the treatment frequency was lower compared to the monthly administration.

[Periocular sub-tenon triamcinolone acetonide injections for the treatment of retinal angiomatous proliferation (RAP) and occult choroidal neovascularisation]. / Periokuläre subtenonale Triamcinoloninjektionen zur Behandlung von retinal angiomatösen Proliferationen (RAP) und okkulten choroidalen Neovaskularisationen.

BACKGROUND: Intravitreal triamcinolone injections are used for the treatment of occult choroidal neovascularisations (CNV) combined with photodynamic therapy (PDT). However, this therapy is not without considerable risks. The periocular mode of application seems to be a logical alternative. PATIENTS AND METHODS: A retrospective case series of 39 eyes with occult CNV either with retinal angiomatous proliferations (RAP) (group A) or with occult choroidal neovascularisation (CNV) (group B), treated with periocular triamcinolone was reviewed. Data regarding efficacy and side effects were extracted. RESULTS: After a mean follow-up of 10 - 11 months 84 % in group A lost < 3 lines of visual acuity (VA). 26 % of them gained > or = 1 line of VA. 16 % lost > or = 3 lines of VA. In group B (19 eyes) VA was stable in 100 %, whereas 20 % gained > or = 1 line. Both groups showed similar results for magnification requirement (MR). A rise in intraocular pressure was found in 15 %. CONCLUSION: In patients with RAP or occult CNV sub-tenon injections seem to delay moderate to severe visual loss. Whether larger randomised controlled studies regarding this treatment are still relevant in the era of anti-VEGF treatments remains to be seen.

Strain fields at contacts between small particles.

Stress fields between interacting small particles ( approximately 100 nm) have been investigated by transmission electron microscopy. The background for these TEM observations is discussed in terms of adhesion stress fields (due to surface forces), the action of an applied point force, possibly magnetic, and dislocations or misfit strains due to an unfavorable matching of crystal lattices at the grain boundary. A further explanation might be sought along the line "squeezed-in oxide" which can be visualized as a coherent particle or a dislocation loop. Accompanying theoretical calculations have been performed and compared with the experimental results.

Fatal combination of moclobemide overdose and whisky.

The antidepressant moclobemide (Aurorix) is a reversible inhibitor of monoamine oxidase-A. Pure moclobemide overdose is considered to be relatively safe. Mixed drug overdoses including moclobemide are potentially lethal, especially when serotonergical drugs are involved. So far, only one fatality due to moclobemide mono-overdose has been reported. We report here on a fatality following the ingestion of a moclobemide overdose in combination with half a bottle of whisky. Although dietary restrictions during moclobemide therapy are not considered necessary, the combination of large quantities of moclobemide and tyramine-containing products seems to be lethal, probably because monoamine oxidase-A selectivity is overwhelmed after massive overdoses. Since there is no specific antidote and treatment is only symptomatic, the severity of an overdose with moclobemide must not be underestimated.

[Reading ability after photodynamic therapy (PDT) for age-related macular degeneration (AMD) and for high myopia]. / Lesefähigkeit nach photodynamischer Therapie (PDT) für altersabhängige Makuladegeneration (AMD) und für hohe Myopie.

BACKGROUND: A prospective uncontrolled follow-up of changes in reading ability after PDT with Verteporfin in patients with predominantly classic subfoveal choroidal neovascularization (CNV) due to AMD or high myopia was carried out. PATIENTS AND METHODS: A follow-up time of at least 6 months is documented for 48 patients with AMD and for 22 patients with high myopia. In addition to the usual clinical parameters the need for magnification was measured using standardized reading charts provided by the SZB.A need for magnification higher than 3.2-fold was defined as a severe loss in reading ability.PDT's were repeated every 3 months according to the usual guidelines. RESULTS: Before treatment, the mean reading acuity for patients with AMD was between 20/200 and 20/100. The average need for magnification was between 2.5-fold and 3.2-fold.Reading acuity, need for magnification and the percentage of patients with a need for magnification of 3.2-fold or less remained stable over a 6-12 months follow-up period. High myopic patients initially had a mean reading acuity of 20/200 and a need for magnification of 2.5-fold. After 9 months follow-up, reading acuity showed a mean improvement from 0.2 up to 0.3 ( p<0.05). There was also a trend towards improvement in the need for magnification and the percentage of patients with a need for magnification of 3.2-fold or less improved significantly from 68% to 78% ( p<0.05). CONCLUSION: Reading ability could be stabilized with PDT for predominantly classic subfoveal CNV in patients with high myopia or AMD for at least 9-12 months. The risk of developing a severe loss in reading ability (need for magnification >3.2-fold) was significantly reduced in high myopia and was stable over time in AMD.

[Acute zonal occult outer retinopathy (AZOOR)]. / Akute zonale okkulte äussere Retinopathie (AZOOR).

BACKGROUND: The "white dot syndromes" are a clinically heterogeneous group of inflammatory chorioretinopathies with an inconsistent classification. It is not yet clear if they represent distinct entities or if they are only different forms of the same basic disease. CASE REPORT: A 53-year-old female patient presented with unilateral photopsia and reduced vision in the left eye. Funduscopy of the left eye showed peripapillary confluent whitish infiltrates in the deep retinal layers with corresponding enlargement of the blind spot. Slow progression of the lesions was observed followed by the development of subretinal fibrosis in the macula. The ERG was reduced in the left eye. In both eyes there were small round, partly confluent areas of RPE atrophy in the lower fundus periphery without inflammatory reaction in the vitreous body or anterior chamber. CONCLUSION: The presented case shows overlapping features of acute zonal occult outer retinopathy (AZOOR), multifocal choroiditis and diffuse subretinal fibrosis and uveitis. This case and other previously described cases with overlaps between different clinical entities support the theory that clinically different inflammatory chorioretinal diseases may represent parts of a spectrum of one common disease.

[Idiopathic sclerochoroidal calcification--case report]. / Idiopathische sklerochoroidale Kalzifikation--eine Kasuistik.

BACKGROUND: Idiopathic sclerochoroidal calcification is a rare benign disorder of the choroid and sclera which has initially been described twelve years ago. Clinically, it is often mistaken for osteoma, choroidal metastasis or infiltration in lymphoma leading to exentsive further investigations. CASE REPORT: A 68-year-old patient had been referred to our outpatient clinic because of unusual fundus changes on both eyes. Ophthalmoscopic examination revealed a yellowish placoid-like lesion in the superotemporal quandrant of the fundus of both eyes, the left lesion being more discrete. Flurescein angiography and echography led to the diagnosis of bilateral ISC. CONCLUSION: Although idiopathic sclerochoroidal calcification can easily be diagnosed by echographic and angiopraphic examination, it is frequently misdiagnosed for malignant tumors thus initiating excessive further investigation.

[Stargardt's disease and its intrafamilial variability]. / Morbus Stargardt mit intrafamiliärer Variabilität.

BACKGROUND: Because of its considerable differential diagnosis and a wide range of phenotypic variation, Stargardt's disease (juvenile macular dystrophy) can cause diagnostic problems. Moreover, ample variability in course and outcome of the disease has been described. PATIENTS AND METHODS: The diagnosis and variable course of Stargardt's disease of three affected siblings have been documented by clinical manifestation, fluorescein angiography and Ganzfeld-ERG including the ISCEV standard protocol. RESULTS: All three siblings presented with retinal abnormalities. However, only the youngest brother revealed symptoms for more than 10 y in terms of reduced visual acuity. The two elder ones had preserved central vision. Classical findings of contact lens biomicroscopy, fluorescein angiography and changes in the Ganzfeld-ERG confirmed the diagnosis of Stargardt's disease. CONCLUSIONS: The diagnosis of Stargardt's disease can be made as late as in the 7th decade of life. Tremendous variability can occur in course and outcome even within the same family. Therefore, visual prognosis is uncertain and has to be made with caution. In most cases the diagnosis can be established with the above mentioned methods.

Characterization of abundance and diversity of lactic acid bacteria in the hindgut of wood- and soil-feeding termites by molecular and culture-dependent techniques.

Lactic acid bacteria have been identified as typical and numerically significant members of the gut microbiota of Reticulitermes flavipes and other wood-feeding lower termites. We found that also in the guts of the higher termites Nasutitermes arborum (wood-feeding), Thoracotermes macrothorax, and Anoplotermes pacificus (both soil-feeding), lactic acid bacteria represent the largest group of culturable carbohydrate-utilizing bacteria (3.6-5.2x10(4) bacteria per gut; 43%-54% of all colonies). All isolates were coccoid and phenotypically difficult to distinguish, but their enterobacterial repetitive intergenic consensus sequence (ERIC) fingerprint patterns showed a significant genetic diversity. Six different genotypes each were identified among the isolates from R. flavipes and T. macrothorax, and representative strains were selected for further characterization. By 16S rRNA gene sequence analysis, strain RfL6 from R. flavipes was classified as a close relative of Enterococcus faecalis, whereas strain RfLs4 from R. flavipes and strain TmLO5 from T. macrothorax were closely related to Lactococcus lactis. All strains consumed oxygen during growth on glucose and cellobiose; oxygen consumption of these and other isolates from both termite species was due to NADH and pyruvate oxidase activities, but did not result in H2O2 formation. In order to assess the significance of the isolates in the hindgut, denaturing gradient gel electrophoresis was used to compare the fingerprints of 16S rRNA genes in the bacterial community of R. flavipes with those of representative isolates. The major DNA band from the hindgut bacterial community was further separated by bisbenzimide-polyethylene glycol electrophoresis, and the two resulting bands were sequenced. Whereas one sequence belonged to a spirochete, the second sequence was closely related to the sequences of the Lactococcus strains RfLs4 and TmLO5. Apparently, those isolates represent strains of a new Lactococcus species which forms a significant fraction of the complex hindgut community of the lower termite R. flavipes and possibly also of other termites.

[Bilateral cystoid macular edema in an older female patient with tubulointerstitial nephritis and uveitis (TINU syndrome)]. / Bilaterales zystoides Makulaödem bei älterer Patientin mit tubulointerstitieller Nephritis und Uveitis (TINU-Syndrom).

BACKGROUND: TINU-Syndrome (Acute tubulointerstitial nephritis and uveitis) is a rare immune-mediated disease, primarily occurring in children and young women. Uveitis may precede, follow or occur concomitantly with nephritis. Corticosteroids are the mainstay of therapy. PATIENT: A 73-year old female patient with tubulointerstitial nephritis and recurrences of anterior uveitis was diagnosed having TINU syndrome. During follow-up she developed bilateral cystoid macular edema with accompanying visual loss. Nephritis and uveitis responded well to oral corticosteroids. CONCLUSIONS: Uveitis screening should exclude renal disease independent of the age of the patient. Diagnosis can often be inferred from anamnesis, physical examination, or laboratory tests. Renal biopsy as the most definite method of diagnosis may be necessary. Ophthalmologic follow-up on a regular basis is mandatory for a successful management of long-term complications.

[Radiotherapy for choroidal neovascularization (CNV) in age-related macular degeneration (AMD)]. / Radiotherapie von choroidalen Neovaskularisationen (CNV) bei altersabhängiger Makuladegeneration (AMD).

AIM OF THE STUDY: Several pilot studies have indicated, that radiation therapy might have a beneficial effect on the course of CNV in AMD. This controlled study was aimed at the question, whether such treatment might halt progression of neovascular AMD and whether a low or a high radiation dose should be applied. METHODS AND PATIENTS: Enclosed were patients aged > or = 60 and < or = 85 and eyes with a VA of > or = 0.1 and < or = 0.6, revealing a juxta/subfoveal CNV either of the occult or the classic type. Treatment was performed with a linear accelerator at fractions of 2 Gy up to a total dose of 10 Gy or 36 Gy. 95 eyes had completed follow-up of > or = 12 < or = 24 months. RESULTS: Among eyes with occult CNV 8 received 36 Gy, 16 were treated with 10 Gy and 21 were in the control group. Mean visual loss was 3.5 lines after 12 months and 5 lines after 24 months with no difference between irradiated eyes and those in the control group. In the groups with classic CNV 8 eyes were treated with 36 Gy, 27 eyes received 10 Gy and 15 eyes were in the control group. Mean visual loss after 6 months was 2.2 lines in eyes of both groups treated with radiation and 5.7 lines in the control group. This was statistically significant (p < 0.05). VA was < 0.1 after 12 (24) months of follow-up in 50 (75)% of the cases with 36 Gy, in 48 (83)% with 10 Gy and in 60 (83)% of the controls. These results were statistically significant after 12 months only. DISCUSSION AND CONCLUSIONS: The natural course of occult CNV could not be improved by irradiation with 10 or 36 Gy. In eyes with classic CNV a VA of > or = 0.1 was maintained significantly more often in irradiated eyes than in those of the control group. Treatment with 36 Gy however was associated with an unacceptable incidence of radiation retinopathy.

Impact of oxygen on metabolic fluxes and in situ rates of reductive acetogenesis in the hindgut of the wood-feeding termite Reticulitermes flavipes.

The symbiotic digestion of lignocellulose in the hindgut of the wood-feeding termite Reticulitermes flavipes is characterized by two major metabolic pathways: (i) the oxidation of polysaccharides to acetate by anaerobic hydrogen-producing protozoa; and (ii) the reduction of CO2 by hydrogenotrophic acetogenic bacteria. Both reactions together would render the hindgut largely homoacetogenic. However, the results of this study show that the situation is more complex. By microinjection of radiolabelled metabolites into intact agarose-embedded hindguts, we showed that the in situ rates of reductive acetogenesis (3.3 nmol termite(-1) h(-1)) represent only 10% of the total carbon flux in the living termite, whereas 30% of the carbon flux proceeds via lactate. The rapid turnover of the lactate pool (7.2 nmol termite(-1) h(-1)) consolidates the previously reported presence of lactic acid bacteria in the R. flavipes hindgut and the low lactate concentrations in the hindgut fluid. However, the immediate precursor of lactate remains unknown; the low turnover rates of injected glucose (< 0.5 nmol termite(-1) h(-1)) indicate that free glucose is not an important intermediate under in situ conditions. The influence of the incubation atmosphere on the turnover rate and the product pattern of glucose and lactate confirmed that the influx of oxygen via the gut epithelium and its reduction in the hindgut periphery have a significant impact on carbon and electron flow within the hindgut microbial community. The in situ rates of reductive acetogenesis were not significantly affected by the presence of oxygen or exogenous H2, which is in agreement with a localization of homoacetogens in the anoxic gut lumen rather than in the oxic periphery. This adds strong support to the hypothesis that the co-existence of methanogens and homoacetogens in this termite is based on the spatial arrangement of the different populations of the gut microbiota. A refined model of metabolic fluxes in the hindgut of R. flavipes is presented.

An intelligent system for pacemaker reprogramming.

The process of reprogramming a cardiac pacemaker can be described in terms similar to those used for describing diagnostic problem solving. In this paper, the process of reprogramming a pacemaker is formalized as a special form of abductive diagnostic reasoning, where observable findings are interpreted with respect to results obtained from diagnostic tests. The dynamics of this process is cast as a diagnostic strategy, where information is gathered in a structured fashion. This abductive theory of pacemaker reprogramming has been used as the basis for an actual system that in its present form is capable of assisting cardiologists in dealing with problems in atrial sensing and pacing. The performance of the system has been evaluated using data from actual patients.

Localization and in situ activities of homoacetogenic bacteria in the highly compartmentalized hindgut of soil-feeding higher termites (Cubitermes spp.).

Methanogenesis and homoacetogenesis occur simultaneously in the hindguts of almost all termites, but the reasons for the apparent predominance of methanogenesis over homoacetogenesis in the hindgut of the humivorous species is not known. We found that in gut homogenates of soil-feeding Cubitermes spp., methanogens outcompete homoacetogens for endogenous reductant. The rates of methanogenesis were always significantly higher than those of reductive acetogenesis, whereas the stimulation of acetogenesis by the addition of exogenous H(2) or formate was more pronounced than that of methanogenesis. In a companion paper, we reported that the anterior gut regions of Cubitermes spp. accumulated hydrogen to high partial pressures, whereas H(2) was always below the detection limit (<100 Pa) in the posterior hindgut, and that all hindgut compartments turned into efficient H(2) sinks when external H(2) was provided (D. Schmitt-Wagner and A. Brune, Appl. Environ. Microbiol. 65:4490-4496, 1999). Using a microinjection technique, we found that only the posterior gut sections P3/4a and P4b, which harbored methanogenic activities, formed labeled acetate from H(14)CO(3)(-). Enumeration of methanogenic and homoacetogenic populations in the different gut sections confirmed the coexistence of both metabolic groups in the same compartments. However, the in situ rates of acetogenesis were strongly hydrogen limited; in the P4b section, no activity was detected unless external H(2) was added. Endogenous rates of reductive acetogenesis in isolated guts were about 10-fold lower than the in vivo rates of methanogenesis, but were almost equal when exogenous H(2) was supplied. We conclude that the homoacetogenic populations in the posterior hindgut are supported by either substrates other than H(2) or by a cross-epithelial H(2) transfer from the anterior gut regions, which may create microniches favorable for H(2)-dependent acetogenesis.

[Physician-assisted suicide for a patient with a psychiatric disorder: guidelines for psychiatrists. Dutch Association of Psychiatry]. / Hulp bij zelfdoding bij een patiënt met een psychiatrische stoornis; richtlijnen voor de psychiater.

In September 1998, the Dutch Association of Psychiatry published guidelines for the psychiatrist concerning cases of psychiatric patients requesting assistance with suicide. Assistance with suicide is restricted to a psychiatrist in his role as a treating physician of a patient with a psychiatric disorder. Requests for assisted suicide should primarily be considered as requests for help with life. Individual psychiatrists have no moral or legal obligation to assist in suicide. The guidelines require that the request is voluntary, explicit and well considered, the desire for death long-lasting and the suffering unbearable and hopeless. In addition an independent psychiatrist should be consulted as well as former treating physicians, general practitioner, family members and other people involved. If a somatic specialist or a general practitioner is asked to assist in suicide consultation of two psychiatrists is required. The guidelines offer psychiatrists a framework for taking great care when their patients request assisted suicide and will certainly play a part in the legal control of assisted suicide.

[Radiotherapy for choroidal neovascularization in age-related macular degeneration. A pilot study using low- versus high-dose photon bean radiation]. / Radiotherapie von subretinalen Neovaskularisationsmembranen bei altersabhängiger Makuladegeneration (AMD). Niedrig- versus hochdosierte Photonenbestrahlung.

PURPOSE: Several pilot studies have indicated that low-dose radiation therapy might have a beneficial effect on the course of choroidal neovascularization (CNV) in age-related macular degeneration (AMD). This study aimed to ascertain whether such treatment might halt the progression of neovascular AMD and whether a low or a high radiation dose should be applied. PATIENTS: The patients comprised some randomized to 0 vs 10 vs 36 Gy of radiation and (after a change of the study protocol became necessary) others who participated in a prospective, controlled non-randomized pilot study. Enclosed were eyes with visual acuity of > or = 0.1 and < or = 0.6 revealing a juxta-subfoveal CNV either of the occult type (type 1) or the classic type (isolated or as part of a predominantly occult lesion). RESULTS: Eyes treated with 10 Gy for occult CNV (n = 12) were subject to severe visual loss in 41.6% of the cases compared to 38.5% in the control group (n = 13) at 12 months of follow-up. For eyes treated with 10 Gy because of classic CNV, the corresponding figures were 33% (n = 18) and 57% (n = 14) respectively. At 18 months of follow-up, the percentages were 63% and 75% respectively. Fluorescein angiographic growth of classic and occult CNV could not be halted by 10 Gy, while a temporary growth retardation was observed in cases irradiated with 36 Gy. CONCLUSION: In the study presented, the natural course of occult CNV could not be improved by irradiation with 10 or 36 Gy. In cases of classic CNV, low-dose irradiation with 10 Gy postponed severe visual loss by a maximum of 18 months. A positive treatment effect was also observed in cases irradiated with 36 Gy; however, a 25% incidence of radiation retinopathy seems unacceptable.

Assessment of the sympatho-vagal interaction in central serous chorioretinopathy measured by power spectral analysis of heart rate variability.

BACKGROUND: The purpose of this study was to measure the activity of the sympathetic nervous system in patients with central serous chorioretinopathy (CSC) by power spectral analysis (PSA) of heart-rate (RR-interval) variability, a noninvasive method that reflects the balance of the sympathetic-vagal interaction. METHODS: The following four different groups of patients were measured; group 1, acute CSC (n = 11); group 2, acute recurrent CSC (n = 7); group 3, chronic persistent CSC (n = 4); group 4, complete remission of CSC (n = 9). The data recorded for these 31 patients (29 men and 2 women), with an average age of 44 years were compared with those noted for a group of 15 age-matched healthy individuals. The sympathetic-vagal balance is expressed by the ratio of the low-frequency component (LF) to the high-frequency component (HF) of the power spectrum. RESULTS: Significant differences in mean LF/HF ratios were found as follows for all but one of the sub-groups as compared with the normal controls (LF/HF = 1.1): group 1, LF/HF = 5.5 (P < 0.01); group 2, LF/HF = 5.4 (P < 0.05); group 3, LF/HF = 4.2 (P = 0.1); and group 4, LF/HF = 3.0 (P < 0.01). There was also a significant difference between active CSC and inactive CSC (P < 0.05). CONCLUSIONS: These results support the view that the pathogenesis of CSC is related to an increase in the sympathetic activity of the autonomic nervous system. Furthermore, the LF/HF ratios seem to correlate with the activity of the disease.