Carrier-Density Control of the Quantum-Confined 1T-TiSe_{2} Charge Density Wave

Using angle-resolved photoemission spectroscopy, combined with first principle and coupled self-consistent Poisson-Schrödinger calculations, we demonstrate that potassium (K) atoms adsorbed on the low-temperature phase of 1T-TiSe_{2} induce the creation of a two-dimensional electron gas (2DEG) and quantum confinement of its charge-density wave (CDW) at the surface. By further changing the K coverage, we tune the carrier density within the 2DEG that allows us to nullify, at the surface, the electronic energy gain due to exciton condensation in the CDW phase while preserving a long-range structural order. Our Letter constitutes a prime example of a controlled exciton-related many-body quantum state in reduced dimensionality by alkali-metal dosing.

[Recommendations for the diagnosis of prosthetic joint infections]

Prosthetic joint infection is the most feared complication of implant surgeries. Its diagnosis continues to be a challenge since its clinical presentation is usually not very evident and overlapping. A high clinical suspicion is needed to make a timely diagnosis. This document represents an updated review of the existing evidence and recommendations, in order to provide a tool that allows professionals to follow a course of action based on current knowledge and available resources, according to the opinion of the members of the Commission of Osteoarticular Infections from the Argentinean Society of Infectious Diseases (SADI).

Periprosthetic fungal infection of a hip caused by Trichosporon inkin

An immunocompromised patient with a history of multiple hip implant revisions extended courses of empiric antibiotic treatment, and a retained metallic rod in the femoral medullary canal was transferred for diagnostic studies and treatment. A high suspicion of fungal infection and utilization of extended and specific fungal cultures were the diagnostic keys for infection with Trichosporon inkin. The treatment consisted in a debridement surgery with the use of a functional spacer with cement supplemented with voriconazole and vancomycin plus a 6-month systemic treatment with voriconazole. After 2 years of follow-up, the patient is free of symptoms.

[Recommendations for prevention of surgical site infection in adult elective arthroplasty]

Surgical site infections complicating orthopedic implant surgeries prolong hospital stay and increase risk of readmission, hospitalization costs and mortality. These recommendations are aimed at: (i) optimizing compliance and incorporating habits in all surgery phases by detecting risk factors for surgical site infections which are potentially correctable or modifiable; and (ii) optimizing preoperative antibiotic prophylaxis as well as intraoperative and postoperative care.

Evaluation of an infectious disease consultation programme in a German tertiary care hospital

PURPOSE

To evaluate a newly implemented infectious disease (ID) consultation service in terms of patient care, outcome and antibiotic prescription and to describe factors influencing adherence to recommendations.

METHODS

Data from consultations during the first 6 months of the ID consultation program were collected and evaluated. Consultation requests, diagnostic results, treatment outcomes and antibiotic recommendations were categorised. Diagnostic and therapeutic recommendations were assessed and rated for adherence and outcome. Statistical analysis was performed to identify factors influencing adherence and treatment outcome.

RESULTS

A total of 251 consultations were assessed. In most cases, ID specialists were asked for further advice regarding a previously initiated anti-infective treatment (N = 131, 52 %). In 54 of 195 (28 %) first consultations, the ID specialist proposed a differential diagnosis that differed from that of the working diagnoses submitted with the consultation request, and which was subsequently confirmed in 80 % of these cases. Diagnostic and therapeutic recommendations were made in 190 (76 %) and 240 (96 %) of the consultations, respectively. A change in the current treatment was recommended in 66 % of consultations; 37 % of recommendations were cost-saving and 26 % were cost-neutral. Compliance with diagnostic and therapeutic recommendations was rated as good by pre-specified criteria in 65 and 86 % of consultations, respectively. Treatment outcome was correlated with adherence to diagnostic recommendations (P = 0.012). Twenty-nine patients (16 %) died during the same hospital stay.

CONCLUSION

Infectious disease consultations may help to establish the correct diagnosis, resulting in the appropriate treatment being provided to a severely sick patient population. Treatment outcome was improved in cases of good diagnostic adherence to the recommendations of the ID specialist.

Clinical assessment of HIV-associated lipodystrophy syndrome: bioelectrical impedance analysis, anthropometry and clinical scores

BACKGROUND

Diagnosis of the HIV-associated lipodystrophy syndrome is based on clinical assessment, in lack of a consensus about case definition and reference methods. Three bedside methods were compared in their diagnostic value for lipodystrophy.

PATIENTS AND METHODS

Consecutive HIV-infected outpatients (n=278) were investigated, 128 of which also had data from 1997 available. Segmental bioelectrical impedance analysis (BIA) and waist, hip and thigh circumferences were performed. Changes in seven body regions were rated by physicians and patients using linear analogue scale assessment (LASA). Diagnostic cut-off values were searched by receiver operator characteristics.

RESULTS

Lipodystrophy was diagnosed in 85 patients (31%). BIA demonstrated higher fat-free mass in patients with lipodystrophy but not after controlling for body mass index and sex. Segmental BIA was not superior to whole body BIA in detecting lipodystrophy. Fat-free mass increased from 1997 to 1999 independent from lipodystrophy. Waist-hip and waist-thigh ratios were higher in patients with lipodystrophy. BIA, anthropometry and LASA did not provide sufficient diagnostic cut-off values for lipodystrophy. Agreement between methods, and between patient and physician rating, was poor.

CONCLUSION

These methods do not fulfil the urgent need for quantitative diagnostic tools for lipodystrophy. BIA estimates of fat free mass may be biased by lipodystrophy, indicating a need for re-calibration in HIV infected populations.

Epiretinal membranes after extracapsular cataract surgery

PURPOSE

To determine whether uneventful extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens (PC IOL) implantation induces epiretinal membranes (ERMs).

SETTING

Private practice, with statistical evaluation at a university department in Germany.

METHODS

This prospective study comprised 296 consecutive patients (332 eyes) who had uneventful ECCE with PC IOL implantation for senile cataract. Eyes were examined within 2 weeks preoperatively and 2 weeks and 6, 9, and 12 months postoperatively. The macula was examined with a 78.0 diopter Volk lens. The main outcome measure was the presence of ERM. The membranes were classified as present when cellophane macular reflex (CMR) or macular pucker (MP) was observed.

RESULTS

The median age of the patients was 78 years (range 50 to 97 years). At baseline, ERM was present in 49 of 332 eyes (14.8%), 40 (12.1%) with CMR and 9 (2.7%) with MP. Six months postoperatively, ERM was present in 84 of 332 eyes (25.3%), 72 (21.7%) with CMR and 12 (3.6%) with MP. The difference between the baseline and 6 month incidence was significant (P <.001). All new cases of ERM were of the CMR type. One year after surgery, ERM was present in 54 of 198 eyes (27.3%), 47 (23.7%) with CMR and 7 (3.5%) with MP. The ERMs rarely influenced visual acuity; however, 6 of 12 eyes (50.0%) with MP and 13 of 72 (18.1%) with CMR had metamorphopsia.

CONCLUSIONS

The prevalence of ERM increased by 71.4% during the first 6 months after uneventful ECCE with PC IOL implantation. Thereafter, the prevalence remained about the same. Newly formed ERMs were probably induced by the uneventful surgery. Although new-onset membranes usually do not preclude good visual acuity, they can cause metamorphopsia postoperatively.

Risk factors for the HIV-associated lipodystrophy syndrome in a cross-sectional single-centre study

OBJECTIVE

Risk factors for the HIV-associated lipodystrophy syndrome (HALS) were studied in a single-centre, cross-sectional study. -

PATIENTS AND METHODS

278 consecutive HIV-infected outpatients at a German tertiary care centre were enrolled. Changes in body shape were quantified using linear analogue scales. Cumulative treatment duration for each antiretroviral drug, CD4 cells, viral load and age were investigated as potential risk factors for a clinical diagnosis of lipodystrophy syndrome by logistic regression.

RESULTS

HALS was diagnosed in 88 patients. The risk of HALS increased significantly with longer protease inhibitor treatment (relative risk 1.61 (95% confidence interval, 1. 24 to 2.09, per year); older age and a history of low CD4 cell counts were cofactors in this multivariate model, but nucleoside analogues did not contribute significantly. Neither pattern nor severity of disease were predicted by these risk factors. Treatment durations and other risk factors were highly correlated with each other.

CONCLUSIONS

These findings support a pathogenetic role for protease inhibitor toxicity, advanced HIV disease, and ageing. No evidence for an additional effect of nucleoside analogues was found. The high correlation of potential risk factors indicates that this and other available studies may be too small to detect multiple risk factors without major confounding.

Phase angle from bioelectrical impedance analysis remains an independent predictive marker in HIV-infected patients in the era of highly active antiretroviral treatment

BACKGROUND

Highly active antiretroviral treatment (HAART) reduces the risk of wasting in HIV infection and may alter the prognostic weight of wasting. The phase angle from bioelectrical impedance analysis (BIA) can be interpreted as a surrogate marker for the catabolic reaction to chronic HIV infection and opportunistic disease.

OBJECTIVE

Our objective was to assess the prognostic ability of the phase angle in HIV-infected patients in the era of HAART.

DESIGN

Two cross-sectional observation studies were conducted in 1996 and 1997 at a German university outpatient HIV clinic. In the 1996 and 1997 cohorts, HAART was prescribed to 17 of 212 and 168 of 257 patients at baseline and to 179 of 212 and 234 of 257 patients during observation, respectively. Whole-body BIA was assessed at 50 KHz. Time to clinical progression and survival were calculated by using Cox proportional hazard models with time-dependent covariates. Median observation times were 1000 and 515 d for the 1996 and 1997 cohorts, respectively.

RESULTS

Higher phase angle was associated with a lower relative mortality risk, adjusted for viral load and CD4(+) cell count, of 0.49 (95% CI: 0.30, 0.81) per degree in 1996 and of 0.33 (95% CI: 0.18, 0.61) in 1997. The influence of phase angle on time to clinical progression, adjusted for viral load and CD4(+) cell count, was not significant in 1996 but the relative risk was 0.58 (0.36, 0.83) in 1997.

CONCLUSION

Despite the favorable effects of HAART on the nutritional status of HIV-infected persons, low phase angle remains an independent adverse prognostic marker of clinical progression and survival.

Assessment of intracellular water by whole body bioelectrical impedance and total body potassium in HIV-positive patients

OBJECTIVE

Bioelectrical impedance analysis (BIA) is widely used as bedside assessment of body composition. Body cell mass (BCM) and intracellular water (ICW) are clinically important body compartments. Estimates of ICW obtained from BIA by different calculation approaches were compared to a reference method in male HIV-infected patients.

PATIENTS

Representative subsample of clinically stable HIV-infected outpatients, consisting of 42 men with a body mass index of 22.4 +/- 3.8 kg/m(2)(range, 13-l31 kg/m(2)).

METHODS

Total body potassium was assessed in a whole body counter, and compared to 50 kHz monofrequency BIA and multifrequency bioelectrical impedance spectroscopy. Six different prediction equations for ICW from BIA data were applied. Methods were compared by the Bland-Altman method.

RESULTS

BIA-derived ICW estimates explained 58% to 73% of the observed variance in ICW (TBK), but limits of confidence were wide (-16.6 to +18.2% for the best method). BIA overestimated low ICW (TBK) and underestimated high ICW (TBK) when normalized for weight or height. Mono- and multifrequency BIA were not different in precision but population-specific equations tended to narrower confidence limits.

CONCLUSION

BIA is an unreliable method to estimate ICW in this population, in contrast to the better established estimation of total body water and extracellular water. Potassium depletion in severe malnutrition may contribute to this finding but a major part of the residual between methods remains unexplained.

Fever and sepsis during neutropenia are associated with expansion of extracellular and loss of intracellular water

BACKGROUND AND AIMS

Shifts from intracellular to extracellular water are features of a catabolic reaction to sepsis. Bedside assessment of fluid shifts was carried out in neutropenic patients at high risk of systemic infection.

METHODS

Multifrequency bioelectrical impedance analysis was performed in 41 patients with leukemia or high-malignant lymphoma and chemotherapy-induced neutropenia.

RESULTS

Hydration was stable during afebrile periods except for transient intra- and extracellular dehydration after chemotherapy. The risk of over-hydration and dehydration increased 3-fold during fever. Over-hydration was more severe when occurring during fever. Extracellular water was highly variable and tended to increase, and intracellular water was slowly depleted. During sepsis, these alterations were enhanced. Changes in hydration status did not predict subsequent progression to sepsis because it developed more slowly than other symptoms of infection.

CONCLUSIONS

Extracellular over-hydration and intracellular dehydration are observed in febrile infection in neutropenia, similar to severe sepsis. If the technical limits of bioelectrical impedance are taken into account, this method may be useful for non-invasive monitoring of these features of metabolic stress.

Oral supplements as adjunctive treatment to nutritional counseling in malnourished HIV-infected patients: randomized controlled trial

AIMS

To compare nutritional counseling with and without oral supplements in HIV-infected patients with recent weight loss.

DESIGN

Randomized non-blinded controlled trial, stratified for change in antiretroviral treatment at baseline.

PATIENTS

HIV-infected patients with recent weight loss (> 5% of total, and >3% in the last month).

INTERVENTION

Nutritional counseling to increase dietary intake by 600 kcal/day over 8 weeks; in group A (n=24) by normal food, and in group B (n=26) by a range of fortified drink supplements with a calorific value of 0.6 to 1.5 kcal/ml.

METHODS

Body composition by bioelectrical impedance analysis, dietary intake by 24 h recall.

RESULTS

Fat free mass increased from baseline to week 8 (P<0.05) with no difference between groups A and B (P=0.97). Body cell mass and weight gain were not significant and equal between groups. Assessed at weeks 2 and 4, group B patients consumed 11 +/- 6 kcal/kg as supplements, and their total energy intake was 6 kcal/kg higher than in group A (P<0.01). Total energy intake was not different between groups at weeks 6 and 8.

DISCUSSION

Nutritional counseling and oral supplements are both feasible methods to restore food energy intake in malnourished HIV-infected patients. Although normal food intake is partially replaced, oral supplements may improve the adherence to a weight gain regimen.

Bioelectrical impedance analysis in HIV-infected patients treated with triple antiretroviral treatment

BACKGROUND

Triple antiretroviral treatment including protease inhibitors (PIs) delays the clinical progression of HIV infection and may thus reduce the risk of malnutrition. However, fat redistribution (lipodystrophy) was recognized recently as a metabolic side effect of PIs.

OBJECTIVE

The study aimed to assess the effect of triple antiretroviral treatment on body composition and on the prevalence of malnutrition.

DESIGN

Two cross-sectional studies, 1 in 1996 (t96; n = 247) and 1 in 1997 (t97; n = 266), were conducted in HIV-infected outpatients. Among patients who participated in both studies, 111 patients started a new antiretroviral treatment including a PI between t96 and t97 and were studied longitudinally. Total body water (TBW), intracellular water (ICW), extracellular water (ECW), and fat mass were estimated by monofrequency bioelectrical impedance analysis (BIA).

RESULTS

Prevalence of malnutrition was reduced by 30-50% from t96 to t97, depending on the definition used. In the longitudinal study, TBW and the ratio between ICW and ECW increased and fat mass decreased (P < 0.001). BIA indicated a greater increase in ICW in 23 (21%) patients with clinically apparent fat redistribution than in patients without this syndrome, but estimates of fat mass changes were not significantly different.

CONCLUSIONS

Triple antiretroviral treatment may protect HIV-infected patients against the development of malnutrition. Whole-body BIA data suggest an increase in appendicular body cell mass associated with improved antiretroviral treatment. However, the method is unreliable in detecting fat redistribution, and current prediction equations will need to be recalibrated for HIV-infected patients receiving highly active antiretroviral treatment.

Body weight changes with protease inhibitor treatment in undernourished HIV-infected patients

Effective reduction of HIV replication by protease inhibitor (PI) treatment was expected to reverse some of the weight loss associated with HIV infection. Body weight changes in undernourished HIV-infected patients starting PI treatment were compared to its virologic and immunologic effects. This was designed as a retrospective study using prospectively collected weight data; the setting was the HIV outpatient department of a university hospital. Among 223 consecutive HIV-positive patients starting treatment with PI February 1996 to September 1997, 63 undernourished patients were evaluable. The main outcome measures were weight trend, calculated by linear regression of a patient's weight versus time, and its change from a 4-14-wk baseline period to the first 14 wk, and 28 wk, after treatment. In our results, weight trend remained unchanged (baseline, +0.4 +/- 4.0 kg/100 d; 14 wk, +0.7 +/- 4.1 kg/100 d, and 28 wk, +1.0 +/- 3.4 kg/100 d, n.s.). Reduction of viremia and increase in CD4 cell count were unrelated to weight trends. Treatment with PI did not result in an improved weight trend. Altered body composition with PI treatment, as observed in other studies, does not seem to result in body weight changes. Drug side effects may have counteracted any positive effects. The metabolic and nutritional impact of effective antiviral treatment merits further study.

Resting energy expenditure, weight loss, and altered body composition in HIV infection

Failure to downregulate resting energy expenditure (REE) as an adaption to anorexia or malabsorption is often stated as the major cause of weight loss in individuals with AIDS. In a prospective study, REE was compared with weight changes in HIV-infected patients. The impact of altered body composition on REE was reassessed by critical review of the literature. Patients were 65 male HIV-infected patients, 28 with recent weight loss (WL), and 37 who were weight stable (WS); 50/65 patients had AIDS, and 29/65 had acute infections; 29 male healthy persons served as controls. Indirect calorimetry, prospective intake protocol, and bioelectrical impedance analysis were performed. Absolute REE was lower in WL patients than in controls (1459 +/- 309 versus 1711 +/- 151 kcal/d, p < 0.001) and in WS patients (1625 +/- 402 kcal/d, p < 0.05). REE/kg body cell mass (BCM) was higher in WL and WS than in controls (both p < 0.01) due to lower BCM in both patient groups (p < 0.001). REE (%Harris-Benedict) was not different among the three groups. Weight changes around the measurement were not correlated to REE (r2 = 0.0008, p = 0.82). REE was independent of diarrhea, acute infection, fever, or caloric intake. REE had a stronger correlation to body weight and to Harris-Benedict's prediction than to fat-free mass or BCM. REE explains < 1% of weight changes. Many patients can downregulate REE as an adaption to anorexia and/or malabsorption. Higher REE/kg BCM does not signify hypermetabolism at the cellular level but can be explained by the maintenance of energy-consuming visceral tissue within the BCM during BCM loss.

[Anhidrotic ectodermal dysplasia. Disorder of the differentiation of hair follicles and sweat glands leads to abnormal keratinization]

We report on an 11-year-old female patient with anhidrotic ectodermal dysplasia (AED) showing the following characteristics: (1) reduced number of hair follicles and incomplete formation of sweat glands; (2) disturbed hair growth with shortening of anagen and anhidrosis; (3) disturbed cytokeratin expression pattern of CK 13, 14, 19 (follicular epithelium) and of CK 18 (eccrine sweat glands); (4) reduction of cystine and increase in sulphonic cysteine acid. Thus, we demonstrated pathological differentiation on the immunomorphological and on the biochemical level, leading to disturbed keratinization that could be visualized by transmission and scanning electron microscopical studies of the hair shafts. According to these findings AED is a developmental defect that involves not only incomplete formation of hair follicles and sweat glands but also a disordered differentiation and follicular keratinization with disturbed cytokeratin pattern and pathological amino acid composition of the terminal hairs produced.

Symmetrical neurofibroma with Schwann cell predominance and focal formation of microneurinomas

A case of symmetrical neurofibroma with onion bulbs in various stages of development and progression to microneurinomas is presented. Immunohistochemistry with differentiation and growth factor markers as well as electron microscopy showed a Schwann cell origin of the concentrically arranged cells. The onion bulbs differed from those of hypertrophic neuropathy by their more compact structure. A partial expression of cellular proliferation markers in the onion bulbs was consistent with a multifocal proliferative activity, confirming the neoplastic nature of the lesion.

[Toxicity of the CYVADIC modification in patients with soft tissue sarcomas or malignant mesotheliomas]

CYVADIC (cyclophosphamide + vincristine + adriamycin + dacarbazine = DTIC) is frequently used in the treatment of patients with soft tissue sarcomas or malignant mesotheliomas. As a modification of the protocol originally published by Gottlieb, the interval between two cycles was extended to 4 weeks for better bone marrow regeneration and vincristine was given only once instead of twice per cycle. A total of 237 cycles of this modified CYVADIC protocol resulted in tolerable toxicity (except nausea and vomiting) and therapeutic results comparable to the original protocol (6/22 complete remissions and 6/22 partial remissions in sarcomas; 1/5 partial remission in mesotheliomas). Hematotoxicity was cumulative after 6 CYVADIC cycles. In contrast to the original Gottlieb scheme there were no severe infections such as pneumonia or sepsis. Neurotoxicity was weak and reversible; cardiotoxicity was not observed. Compared to the protocol originally suggested by Gottlieb, the modified CYVADIC regimen appears to be as effective but less toxic.

Reno-cerebral oxalosis induced by xylitol

A 20-year-old man suffering from Crohn's disease developed coma and generalized seizures following ileocecal resection. During postoperative parenteral feeding he received xylitol in an unusually high concentration. CT examinations a few days before death showed intense hypodensity and swelling of brainstem and basal ganglia and increasing triventricular dilatation. Autopsy revealed, mainly in the brainstem and cerebellum, a destruction of intracerebral, intracerebellar and leptomeningeal vessel walls by birefringent crystals (probably calcium oxalate), an early inflammatory reaction and severe brain edema with final tonsillar herniation. The same crystalloid deposits were found in the kidneys.

Pharmacokinetics of triamterene after i.v. administration to man: determination of bioavailability

With a new formulation, which made intravenous infusion of triamterene (TA) possible, plasma levels and urinary excretion rates of TA and its main metabolite (OH-TA-ester) were measured in a randomized, cross-over trial in 6 healthy volunteers given triamterene 10 mg i.v. and 50 mg p.o. TA and OH-TA-ester were determined by densitometric measurement of native fluorescence after thin layer chromatography. Distribution volumes of the central compartment of TA and OH-TA-ester were 1.49 l/kg and 0.11 l/kg, respectively. Terminal half-lives were 255 min for TA and 188 min for OH-TA-ester after i.v. administration. For TA total plasma clearance was 4.5 l/min and renal plasma clearance 0.22 l/kg. The formation of OH-TA-ester was very rapid and the concentration of the metabolite exceeded that of TA at all times. After i.v. administration the urinary recovery of TA and OH-TA-ester was 4.4% and 50.9%, respectively. The bioavailability of TA was 52%, corresponding to absorption of 83%. TA is partly eliminated by a first-pass-effect. The main metabolite of TA is OH-TA-ester, which is pharmacologically active.

[Intraoperative epidural opiate analgesia for pain treatment after spine surgery (author's transl)]

The intraoperative epidural opiate application seems to solve the problem of postoperative pain treatment after surgery of the vertebral column. For this purpose 2 mg of morphine in 1,0 ml NaCl-solution are placed epidurally in the root region, just prior to wound closure. 35 patients were treated in this manner and all of them, that means 100%, needed no analgetic in the first 16--24 hours after the operation. The patients feel remarkably better and nursing is facilitated. Intensive supervision however is essential during this time to prevent the risk of ascending diffusion of the morphine to the medullary regulating centers.

[Mass rearing of the Pharoah's ant Monomorium pharaonis]

New techniques for the mass rearing of the Pharaoh's ant (Monomorium pharaonis) are described. The basic idea in doing this is the enlargement of the surface of the rearing containers in order to guarantee the lapse of normal behaviour such as the search for food and recruitment. The rearing container is an aquarium inside of which a great number of levels of glass are located, which are connected with each other. The watering of the colonies is effected by wet cotton wool in petridishes in the lower parts of the rearing devices. A transposition of the colonies in intervals of 6 to 8 months is recommended. A dispersation method of great colonies to small and physiologically equal laboratory colonies is described. A further mass rearing device allowes a strong enlargement of the surface of normal rearing dishes of 20 to 30 cm in diameter. The basic principle consists in the setting into each other of separate dishes. To prevent an outbreak from these rearing containers the walls are prepared with residues of talcum powder. The methods and devices mentioned make it possible to produce great masses of experimental material under constant control of the developmental status at low costs and little need of space.

Correlation between isoprenaline-stimulated synthesis of cyclic AMP and occurrence of beta-adrenoreceptors in immature erythrocytes from rats

When increasing reticulocytosis (up to 80%) was induced in rats by treatment with acetyl-phenylhydrazine (up to 70 mg/kg on 3 consecutive days) synthesis of cAMP stimulated by isoprenaline in intact red blood cells and in the related membrane preparations increased up to 100-fold. At the same time the density of beta-adrenoreceptor sites (measured by ligand binding with (3H)(-)-dihydroalprenolol) in the related membrane preparations was only increased about 5-fold. There was however a linear correlation between the increase of isoprenaline-stimulated enzyme activity and the receptor density in membrane preparations. The results indicate that mature red cells contain beta-adrenoreceptor sites but little or not adenyl cyclase activity. Thus, during the maturation process of these cells, enzyme activity and receptor densities decrease at different speeds indicating a different turnover of these two entities of the cytoplasmic membrane.

[Studies on the incidence and clinical importance of the valve independent, arrested hydrocephalus (author's transl)]

Between 1964 and 1974 193 infants up to the age of 2 years were treated for progressive hydrocephalus by means of a ventriculo-atrial shunt. Long term follow-up studies were possible on 148 children. Among these 94 have functioning and 54 non-functioning valves. The criteria for the non-function were based on either plain X-rays of the skull and thorax (disconnection of the catheters, distal end of the cardiac catheter above D 2), direct punctures of the antichamber and contrast medium studies of the diversional system. 35 children with non-functioning valves were normal in their mental and motor development, 9 were retarded according to their primary brain damage, 10 patients showed signs of chronic increased intracranial pressure. These results suggest, that about one fourth of the valve treated patients develop a state of valve independency.