Positive effect of leptin substitution on mood and behaviour in patients with congenital leptin deficiency

BACKGROUND

States of starvation are characterized by reduced physical activity and social withdrawal. This has been suggested to be mediated at least in part via reduced leptin concentrations.

OBJECTIVE

We therefore aimed to ascertain if leptin substitution in patients with congenital leptin deficiency (CLD) can improve physical activity and mood.

METHODS

Seven patients with CLD were filmed prior to and after short- and long-term substitution (2-21 days; 3-4 months) in a play situation. Six independent, blinded investigators ranked each video according to specifically developed scales concerning motor activity, social interaction, emotionality, and mood with higher scores representing improvements.

RESULTS

Short term metreleptin substitution significantly increased mean total score from 17.7 ± 4.1 to 22.6 ± 6.6 (p = 0.039), and mean scores for motor activity (4.1 ± 1.1 to 5.1 ± 1.5, p = 0.023) and social interaction (4.6 ± 1.1 to 6.2 ± 1.7, p = 0.016). After long term substitution means of all four single scales and of total score were even higher than at short-term follow-up. During a treatment pause of 3 months in two children, all four scale scores fell below substitution levels and rose again after restart.

CONCLUSIONS

Metreleptin substitution improved indices of physical activity and psychological wellbeing in patients with CLD. This suggests that reduced leptin concentrations might be in part responsible for emotional and behavioural changes seen during starvation.

Acute inflammation and psychomotor slowing: Experimental assessment using lipopolysaccharide administration in healthy humans

Data from clinical and cross-sectional studies suggest that inflammation contributes to psychomotor slowing and attentional deficits found in depressive disorder. However, experimental evidence is still lacking. The aim of this study was to clarify the effect of inflammation on psychomotor slowing using an experimental and acute model of inflammation, in which twenty-two healthy volunteers received an intravenous injection of lipopolysaccharide (LPS, dose: 0.8 ​ng/kg body weight) and of placebo, in a randomized order following a double-blind within-subject crossover design. A reaction time test and a go/no-go test were conducted 3 ​h after the LPS/placebo injection and interleukin (IL)-6 and tumor necrosis factor (TNF)-α concentrations were assessed. No effect of experimental inflammation on reaction times or errors for either test was found. However, inflammation was related to worse self-rated performance and lower effort put in the tasks. Exploratory analyses indicated that reaction time fluctuated more over time during acute inflammation. These data indicate that acute inflammation has only modest effects on psychomotor speed and attention in healthy subjects objectively, but alters the subjective evaluation of test performance. Increased variability in reaction time might be the first objective sign of altered psychomotor ability and would merit further investigation.

Immunological and behavioral responses to in vivo lipopolysaccharide administration in young and healthy obese and normal-weight humans

Obesity is associated with an increase prevalence of neuropsychiatric symptoms and diseases, such as depression. Based on the facts that pro-inflammatory cytokines are able to modulate behavior, and that obesity is characterized by a chronic low-grade inflammatory state, inflammation has been hypothesized to contribute to the neuropsychiatric comorbidity in obese individuals. However, a causal link between inflammation and the development of neuropsychiatric symptoms is hard to establish in humans. Here, we used an inflammatory stimulus, i.e. the intravenous injection of lipopolysaccharide (LPS), in a double-blind placebo-controlled design, to determine the vulnerability of obese individuals to inflammation-induced behavioral changes. The hypothesis was that obese individuals would show heightened behavioral response compared to normal-weight subjects for the same inflammatory stimulus, reflecting an increased sensitivity to the behavioral effects of pro-inflammatory cytokines. LPS (dose 0.8 ng/kg body weight, adjusted for estimated blood volume in obese subjects) and placebo (saline) were intravenously injected in 14 obese healthy subjects and 23 normal-weight healthy subjects in a within-subject, randomized, crossover design. LPS administration induced, in both groups, an acute increase in blood concentrations of cytokines (interleukin-6, tumor necrosis factor-α, and IL-10), as well as in body temperature, cortisol, norepinephrine, sickness symptoms, fatigue, negative mood, and state anxiety. There were little differences in the immune and behavioral responses to LPS between obese and normal-weight subjects, but the cortisol response to LPS was strongly attenuated in obese individuals. Higher percentage of body fat was related to a lower cortisol response to LPS. Taken together, the population of young and healthy obese individuals in this study did not exhibit an increased behavioral sensitivity to cytokines, but an attenuated cortisol response to the immune challenge. Future studies will need to determine whether additional physiological and psychological factors interact with the state of obesity to increase the risk for inflammation-induced neuropsychiatric symptoms.

[Psychosocial Characteristic and Health Care for Unemployed Youths with Extreme Obesity - A Model Project]

INTRODUCTION

In clinical care, unemployed youths have limited access to available obesity treatments including obesity surgery. With the implementation of a specialized obesity outpatient unit in cooperation with five German job-centers we aim to prove whether unemployed youths are interested in obesity treatment and how they adhere to a multilevel obesity treatment in terms of participation rates.

MATERIALS AND METHODS

Youths (aged 15.0-24.9 years) with a body-mass-index (BMI) ≥30 kg/m² were initially offered an individualized patient information concerning obesity treatment on the premises of the job-center. If interested, youths were included in the multicomponent treatment program (6 sessions). Those who participated in a minimum of 5 out of 6 treatment sessions were offered access to a preparation course (4 sessions) and an individualized evaluation of the indication for obesity surgery.

RESULTS

Between 2012 and 2017, 83 youths (mean age 21.1 years, BMI 48.1 kg/m², BMI 35.0-39.9 kg/m²: N=7, ≥40 kg/m²: N=71) were enrolled in the treatment program. 34 participated in ≥5/6 sessions in the multicomponent obesity treatment and 20 expressed an interest in obesity surgery. To date, 11 adolescents underwent obesity surgery with a mean BMI reduction of 14.3 kg/m² between 3 and 36 months after obesity surgery (excess weight loss 27.3%) vs. 3.8 kg/m² between 6 and 48 months after treatment initiation in the group of youths who did not receive obesity surgery. 13 youths were integrated in the primary labor market.

DISCUSSION

Several unemployed youths accepted our treatment program and improved their health and vocational status in the course of their participation.

CONCLUSIONS

The implementation of a specialized obesity outpatient unit within German job-centers is a successful strategy to characterize this high-risk-group and to determine their individual treatment needs. This finding must be confirmed with a larger sample size and by evaluating the long-term course of treatment.

[Complications of corneal lamellar refractive surgery]

Techniques available for corneal lamellar refractive surgery are laser-assisted in situ keratomileusis (LASIK) using a microkeratome or femtosecond laser incision followed by excimer laser corneal ablation, and femtosecond laser-assisted refractive lenticule extraction (ReLEx). These treatments are nowadays considered to be safe and effective standard procedures for surgical correction of mild to moderate ametropia. Possible complications include too small or decentered optical zones, intraoperative flap cutting errors and postoperative inflammation (e.g. diffuse lamellar keratitis, DLK), epithelial or flap folds, epithelial ingrowths or iatrogenic ectasia. The occurrence of complications may be significantly reduced by compliance to corresponding standards of indication and treatment that are based on current scientific knowledge.

Whatever their differentiation status, human progenitor derived - or mature - endothelial cells induce osteoblastic differentiation of bone marrow stromal cells

Association of the bone-forming osteoblasts (OBs) and vascular endothelial cells (ECs) into a biomaterial composite provides a live bone graft substitute that can repair the bone defect when implanted. An intimate functional relationship exists between these cell types. This communication is crucial to the coordinated cell behaviour necessary for bone development and remodelling. Previous studies have shown that direct co-culture of primary human osteoprogenitors (HOPs) with primary human umbilical vein endothelial cells (HUVECs) stimulates HOPs differentiation and induces tubular-like networks. The present work aims to test the use of human bone marrow stromal cells (HBMSCs) co-cultured with human endothelial progenitor cells in order to assess whether progenitor-derived ECs (PDECs) could support osteoblastic differentiation as mature ECs do. Indeed, data generated from the literature by different laboratories considering these co-culture systems appear difficult to compare. Monocultures of HUVECs, HOPs, HBMSCs (in a non-orientated lineage), PDECs (from cord blood) were used as controls and four combinations of co-cultures were undertaken: HBMSCs-PDECs, HBMSCs-HUVECs, HOPs-PDECs, HOPs-HUVECs with ECs (mature or progenitor) for 6 h to 7 days. At the end of the chosen co-culture time, intracellular alkaline phosphatase (ALP) activity was detected in HOPs and HBMSCs and quantified in cell extracts. Quantitative real-time polymerase chain reaction (qPCR) of ALP was performed over time and vascular endothelial growth factor (VEGF) was measured. After 21 days, calcium deposition was observed, comparing mono- and co-cultures. We confirm that ECs induce osteoblastic differentiation of mesenchymal stem cells in vitro. Moreover, HUVECs can be replaced by PDECs, the latter being of great interest in tissue engineering.

[An in-vivo evaluation of Brilliant Blue G in macular surgery]

OBJECTIVE

The aim of this study was to evaluate the functional outcome of Brilliant Blue G (BBG) and the staining properties in macular surgery.

METHODS

BBG was applied during vitrectomy for macular holes (n = 21) or epiretinal membranes (n = 18) in a prospective, non-comparative consecutive series of patients (Brilliant Peel®; Fluoron® GmbH, Neu-Ulm, Germany). Before and after surgery all patients underwent a complete clinical examination including measurement of best corrected visual acuity and intraocular pressure, perimetry, fundus photography and optical coherence tomography.

RESULTS

Vitrectomy was performed in combination with a cataract operation in 14 patients. All macular holes were closed successfully. Visual acuity was in average 0.16 preoperatively in macular hole cases and increased up to 0.4 after 6 months. Visual acuity of patients with epiretinal membranes changed on average from 0.3 to 0.45 after 6 months. The retina thickness in patients with epiretinal membranes was initially 402.6 µm according to the OCT and 304.7 µm after 6 months postoperatively. No toxic effects attributable to the dye were noted during patient follow-up, especially all perimetry tests were normal.

CONCLUSIONS

Brilliant blue provides a sufficient and selective staining of the ILM. No retinal toxicity or adverse effects related to the dye were observed in this study. The long-term safety of this dye will have to be evaluated in larger patient series and a longer follow-up.

An in vivo evaluation of Brilliant Blue G in animals and humans

BACKGROUND/AIMS

To evaluate the retinal toxicity of Brilliant Blue G (BBG) following intravitreal injection in rat eyes and examine the biocompatibility and the staining properties in humans.

METHODS

BBG was injected into the 11 rat eyes to evaluate toxic effects with balanced salt solution (BSS) serving as control. Retinal toxicity was assessed by retinal ganglion cell (RGC) counts and by light microscopy 7 days later. In addition, BBG was applied during vitrectomy for macular hole (MH) (n = 15) or epiretinal membranes (ERM) (n = 3) in a prospective, non-comparative consecutive series of patients. Before and after surgery, all patients underwent a complete clinical examination including measurement of best corrected visual acuity (VA) and intraocular pressure, perimetry, fundus photography and optical coherence tomography. Patients were seen 1 day before surgery and then in approximately four weeks intervals.

RESULTS

No significant reduction in RGC numbers and no morphological alterations were noted. A sufficient staining of the internal limiting membrane (ILM) was seen in patients with MH, while the staining pattern in ERM cases was patchy, indicating that parts of the ILM were peeled off along with the ERM in a variable extent. All MHs could be closed successfully. VA improved in 10 eyes (56%; 8/15 MH patients, 2/3 ERM patients), was unchanged in four eyes (22%; all MH patients) and was reduced in four eyes (22%; 3/15 MH, 1/3 ERM). No toxic effects attributable to the dye were noted during patient follow-up. The ultrastructure of tissue harvested during surgery was unremarkable.

CONCLUSION

Brilliant Blue provides a sufficient and selective staining of the ILM. No retinal toxicity or adverse effects related to the dye were observed in animal and human studies. The long-term safety of this novel dye will have to be evaluated in larger patient series and a longer follow-up.

The storage of sewage sludge: influence of liming on the evolution of copper chemical fractions

Sewage sludge re-used in agriculture has to be stabilized and is often stored for several months before land spreading. Stabilization treatment may affect the behaviour of heavy metals such as Cu, which is an element potentially toxic to the environment. In the present study, the chemical forms of copper have been investigated in heaps of limed and unlimed sludge coming from the wastewater treatment plant of Roselies (Belgium). These limed and unlimed aerobically digested sludges were stored during 4 mo in controlled conditions close to field ones. The sequential extraction procedure developed by Tessier was used to determine the copper chemical forms of representative samples taken in the outer shell and in the depth of the heaps. The physico-chemical properties (pH, organic matter, dry matter and temperature) of these samples were also monitored. This study shows that liming transforms part of organically-bound copper into both exchangeable and residual copper. These changes mainly occur during the first 2 wk of storage. After several months of storage, copper passes from the residual fraction to the exchangeable and oxide fractions. During the whole experiment, changes occur faster in the outer shell than in the depth of the heaps. Thus, we demonstrate that the distribution of the copper forms depends on the storage time and it is different in the outer shell from that in the depth of the heaps.

A general model of reaction kinetics in biological systems

Dynamic mathematical models in biotechnology require, besides the information about the stoichiometry of the biological reaction system, knowledge about the reaction kinetics. Modulation phenomena like limitation, inhibition and activation occur in different forms of competition with the key enzymes responsible for the respective metabolic reaction steps. The identification of a priori unknown reaction kinetics is often a critical task due to the non-linearity and (over-) parameterization of the model equations introduced to account for all the possible modulation phenomena. The contribution of this paper is to propose a general formulation of reaction kinetics, as an extension of the Michaelis-Menten kinetics, which allows limitation/activation and inhibition effects to be described with a reduced number of parameters. The versatility of the new model structure is demonstrated with application examples.

Liming as an advanced treatment for sludge sanitisation: helminth eggs elimination--Ascaris eggs as model

The presence of helminth eggs (Ascaris eggs) in sewage sludge may constitute a sanitary risk when used as agricultural fertiliser. Sanitisation of sewage sludge can be achieved by treatment with quick lime, a process that destroys sludge pathogens in two ways: pH increase and temperature rise. Among the pathogens of epidemiological relevance, Ascaris eggs are the most resistant to liming, and, hence, may serve as indicators of hygienic quality of biosolids. This research aims at defining, between 50 degrees C and 60 degrees C, the time required in the case of limed sludge to obtain a product with a negligible level of viable Ascaris eggs. To achieve this objective, investigations on inactivation kinetics of Ascaris eggs were conducted in the following products: contaminated milk of lime; naturally contaminated sludge treated with slaked lime and heat; naturally contaminated sludge treated with quick lime; and sludge treated at full scale with quick lime. For the inactivation kinetics where a negligible level of Ascaris eggs was reached, the inactivation threshold was determined. Depending on the experimental situation, the inactivation threshold period was found to fluctuate between 5 and 75 min at 55 degrees C and between 1 and 8 min at 60 degrees C.

[Male osteoporosis]

AN UPCOMING PUBLIC HEALTH PROBLEM: There has been a considerable focus on osteoporosis in men recently. Bone mass is high in men who have larger bones than women. The frequency of fractures is also higher due to post-trauma lesions. Femoral neck fractures have also increased over the last few years although the F/M ratio remains about 2.8. Overall, there is a trend towards an increased incidence of masculine osteoporosis (and vertebral fractures) due to population aging. FAVORING FACTORS IN MEN: The most important factors are hypoandrogenism, hypoestrogenism (pre or post-puberty), the alcohol-smoking association, malnutrition, lack of sun exposure and chronic liver disease. Other causes of osteoporosis (hyperthyroidism, Cushing's disease, hemochromatosis, gastrectomy, inflammatory rheumatic disease, tubulopathy, hypercalciuria and iatrogenic causes) should also be taken into consideration. PRETHERAPY WORK-UP: All the different possible etiologies should be investigated. Therapeutic protocols should provide hormone replacement when required, withdrawal of causal drugs, better nutrition and reduced alcohol and tobacco use.

Dynamic model of airway pressure drop

A multipath model of the mechanical behaviour of healthy lungs subject to a plethysmographic test (close to quiet breathing conditions) has been developed, which includes the main physiological nonlinearities. This model is built on a symmetric branching scheme based on Weibel's data, and uses non-linear fluid equations for the upper and lower airways. The alveolar gas compression, the changes in airway dimensions related to lung volume and/or transmural pressure, and the respiratory swings in glottic aperture have been taken into account. As clinically observed, the behaviour of the lungs, taken as a whole, seems linear, but it is confirmed by simulation that this linearity is only apparent. Simplifications and linearisations therefore need to be made carefully, only after their impact on the global behaviour of the lung is evaluated.

Up-regulation of thrombomodulin is inducible on an endothelialized polyester

The concept of endothelial cell seeding of vascular prostheses is designed as a method for improving long-term patency substitutes because endothelium is considered as the haemocompatible surface of reference. The assessment of the functionality of cells lining a biomaterial is thus of crucial importance. We have reported encouraging results concerning the ability of a polyester coated with albumin and chitosan (M 11) to be lined by a confluent monolayer of cultured human endothelial cells (EC). The aim of the present work was to study the expression of thrombomodulin (membrane glycoprotein responsible for anticoagulant activity) in EC lying on M.11 by anticoagulant activity and mRNA level with and without stimulation. Results obtained in basal conditions showed that EC on M.11 have a comparable expression of TM mRNA when compared to control (EC on tissue culture plates) despite a lower TM surface activity for EC on the biomaterial. In terms of ratio (stimulated cells to unstimulated ones) the response in activity for EC on M.11 is comparable to that of the control. These results indicate that cells lying on M.11 are able to respond to physiological-like stimuli, despite a tendency for these cells to express a procoagulant phenotype when compared with control EC.

Erdheim-Chester disease. Clinical and radiologic characteristics of 59 cases

We made a retrospective evaluation of clinical and radiologic features, treatment, and outcome of Erdheim-Chester disease, a rare non-Langerhans cell histiocytosis. We had 7 patients coming from 3 French teaching hospitals and reviewed 52 cases from the literature. These cases were considered to have Erdheim-Chester disease when they had either typical bone radiographs (symmetrical long bones osteosclerosis) and/or histologic criteria disclosing histiocytic infiltration without features for Langerhans cell histiocytosis (no S-100 protein, no intracytoplasmic Birbeck granules). Ages at diagnosis ranged from 7 to 84 years (mean +/- SD = 53 +/- 14 yr) with a male/female ratio of 33/26. Bone pain was the most frequent clinical sign (28/59), mostly located in the lower limbs. Exophthalmos and diabetes insipidus were found in respectively 16/59 and 17/59 patients. General symptoms (fever, weight loss) and "xanthomas" (mainly located on the eyelids) were present in 11/59 patients. Retroperitoneal involvement was found in 17/59 patients. Skeletal X-ray showed typical osteosclerosis of the diaphysis of the long bones in 45/59 patients. Bone radiographs showed osteolytic lesions of the flat bones (skull, ribs) in 8 patients. Histologic diagnosis was performed after a bone biopsy (28 patients), a retroorbital biopsy (9 patients), and/or a biopsy of the retroperitoneal infiltration or the kidney (11 patients). Six of our 7 patients but only 5 of 52 patients from the literature had the complete histologic criteria, disclosing no Birbeck granules or S-100 immunostaining. In other cases, histologic results usually described a xanthogranulomatous infiltration by foamy histiocytes nested in fibrosis. Treatment was corticotherapy (20/59), chemotherapy (8/59), radiotherapy (6/59), surgery (3/59) and immunotherapy (1 patient). Twenty-two patients died after a mean follow-up of 32 +/- 30 mo (range, 3-120 mo). In conclusion, Erdheim-Chester disease may be confused with Langerhans cell histiocytosis as it sometimes shares the same clinical (exophthalmos, diabetes insipidus) or radiologic (osteolytic lesions) findings. However, it also appears to have distinctive features. Patients are older and have a worse prognosis than those with Langerhans cell histiocytosis, and the diagnosis relies on the association of specific radiologic and histologic findings.

Thermal behavior of the constant volume body plethysmograph

The thermal behavior of the constant volume body plethysmograph under the thermal effect of the patient and the thermostatic bag is modeled by two relations: the first is between the temperature in the box and the heat flux generated by the patient and the bag, and the second is between the pressure in the box and the same flux. When the heat flux evolves as a step function, the temperature and the pressure are characterized by four time constants, the theoretical values of which are functions of the heat transfer coefficients by natural convection between the faces of the walls, and the air inside and outside the box. Only two of these four theoretical constants can be experimentally measured with reasonable precision. One of these is responsible for an important delay between the installation of the patient in the box and the disappearance of the disturbance thereby created in the pressure signal. Investigations with patients and with three different plethysmographs each built of a different material (wood, PVC, and Perspex) show the influence of the construction material on the waiting period before the disappearance of the disturbance in the pressure signal.

Beware of commercial human thrombins used to stimulate cultured endothelial cells

In the field of in vitro biocompatibility testing, the investigation of cell response at the interface with a biomaterial is of great importance; there is a need for standard conditions and thus of well-defined and reliable sources of materials for an objective evaluation of cellular function. Thrombin is often used in vitro as a stimulating agent to check the specific functions of cultured endothelial cells. In the present work, and in order to select a thrombin of commercial origin, two criteria were borne in mind: purity towards the presence of the von Willebrand factor (vWF) and effectiveness towards vWF release by human umbilical venous endothelial cells (HUVEC) that have been submitted to four human commercial thrombins. We detected the presence of vWF in some thrombin solutions that have not yet been in contact with HUVEC. The different thrombins contained vWF antigen ranging from less than 0.1 mUnit per NIH unit of thrombin (from Diagnostica Stago and Sigma Chemical Co.) to 10-20 mUnit per NIH unit of Fibrindex thrombin (from Ortho Diagnostic Systems). Thus, if vWF is present in commercial thrombins, it contributes to and overestimates the vWF appearance in the media resulting from cell stimulation. Consequently, we fixed on thrombin from Diagnostica Stago for further studies involving HUVEC on biomaterials.

Evaluation of cell colonization on biomaterials: preventing cell attachment to plastic containers

In biocompatibility evaluation involving cell culture models, we use samples of biomaterials of different forms and sizes. During cell seeding onto biomaterials of an inadequate size to cover the bottom of the culture wells completely, cells have the opportunity to attach to the plastic. As described in this report with two culture models and two biomaterials, we use an agarose gel sublayer to prevent this phenomenon.

Jaw movement kinematics and jaw muscle (EMG) activity during drinking in the pigeon (Columba livia)

Movements of the maxilla and mandible were recorded during drinking in the head-fixed pigeon and correlated with electromyographic activity in representative jaw muscle groups. During drinking, each jaw exhibits opening and closing movements along both the dorso-ventral and rostro-caudal axes which may be linked with or independent of each other. All subjects showed small but systematic increases in cycle duration over the course of individual drinking bouts. Cyclic jaw movements during drinking were correlated with nearly synchronous activity in the protractor (levator) of the upper jaw and in several jaw closer muscles, as well as with alternating activity in tongue protractor and retractor muscles. No EMG activity was ever recorded in the lower jaw opener muscle, suggesting that lower jaw opening in this preparation is produced, indirectly, by the contraction of other muscles. The results clarify the contribution of the individual jaws to the generation of gape variations during drinking in this species.

Retinal afferents to the tectum opticum and the nucleus opticus principalis thalami in the pigeon

The retinal afferents of the tectum opticum and the n. opticus principalis thalami (OPT) were studied with fluorescent tracers in pigeons. Injections into the tectum opticum revealed topographically related areas of high density labelling in the contralateral retina. In these areas up to 15,000 cells/mm2 were labelled. After tectal injections the soma sizes of labelled retinal ganglion cells in the area centralis ranged from 5 to 23 microns with a mean of 7.5 microns. Afferents from the ipsilateral retina could not be demonstrated. Injections into the OPT labelled neurons throughout the retina without a clear topographical relation to the locus of injection. The density never exceeded 150 cells per mm2. The soma size range was 8 to 35 microns with a mean of 14.6 microns. Independently of the injection area within the OPT, the red field in the dorsotemporal retina was always extremely sparsely labelled. The number of labelled ganglion cells in this area never exceeded 25 neurons/mm2. After OPT injections the average density of labelling per unit area was six times higher in the yellow than in the red field. The results confirm previous reports of a massive and topographically organized retinal projection onto the optic tectum. The projection onto the OPT was clearly smaller and with the retrograde tracing techniques in use, an orderly topography has not been demonstrated. The paucity of red field projections onto the OPT suggests that the role of the thalamofugal pathway in binocular integration is very limited.

Directional dependence of intraocular transfer of stimulus detection in pigeons (Columba livia)

The eyes of the pigeon (Columba livia) are positioned laterally in the head. Thus, there is only a small area of binocular overlap, which constitutes the frontal visual field and a large area of monocular vision in the lateral visual fields. The conditions were examined under which intraocular transfer occurs in pigeons; that is, the transfer of information between both portions of the visual field of one eye. Different groups of head-fixed birds learned to discriminate the presence of a bright light from its absence in an instrumental conditioning situation with water as reinforcer. After the animals had acquired the task when the stimuli were viewed in either the frontal or lateral visual field, the stimuli were moved into the converse visual field. Transfer was shown to be directionally selective: It occurred when stimulus presentation was changed from the lateral to the frontal visual field but not when this change was in the opposite direction.

Assistant programming software: a new tool for an improved programming of pacemakers

Programming the new DDD pacemakers is becoming increasingly difficult. One must take into account the pacemaker's complexity, the fact that some parameters are linked to others, and the clinical profile of the patient. This difficult problem will lead to the design of software to assist programming, which will help the implanting physicians in choosing adequate programmed settings adapted to the functioning of the device and to the physiology and pathology of the patient. These programming aides should meet certain basic requirements to make them safe, efficient, and easy to use. One such system designed by ELA Médical, "Programming Assistant" is herein described. The preliminary results of an initial study on the acceptance of this programming aide among physicians involved in cardiac pacing are given and discussed.

The topographical projection of the nucleus isthmi pars parvocellularis (Ipc) onto the tectum opticum in the pigeon

The projection of the nucleus isthmi pars parvocellularis (Ipc) onto the tectum opticum was studied with tectal injections of three different fluorescent tracers and wheat germ-agglutinated horseradish peroxidase (WGA-HRP) in 21 pigeons. In frontal sections obtained, the relationship between position and size of the tectal injection and the location of the retrogradely labelled Ipc neurons were analyzed. The results reveal a topographically organized system with reciprocal projections in which the dorsoventral axis of the tectum receives afferents from the lateromedial axis of the Ipc. The caudorostral tectal axis is innervated by neurons situated along the caudorostral axis of the Ipc. Specific points on the tectal surface do not correspond to single points within the Ipc, but to column-like strings of Ipc neurons extending through the dorsoventral aspect of the nucleus.

Behavioral spectral sensitivities of different retinal areas in pigeons

The spectral sensitivity of the red and the yellow retinal fields of head-fixed pigeons was separately measured for wavelengths between 340 and 640 nm by a behavioral perimetric technique. Within this spectral range the mean spectral sensitivity of both fields was found to be maximal at 584 nm and minimal at the lower ultraviolet wavelengths. Differences in sensitivity were found, however, at shorter wavelengths, with the yellow field being more sensitive than the red at wavelengths below 500 nm and especially in the ultraviolet spectral range. These sensitivity differences are discussed in relation to other functional differences between the pigeon's retinal fields.

Behavioral spectral sensitivities of different retinal areas in pigeons

The spectral sensitivity of the red and the yellow retinal fields of head-fixed pigeons was separately measured for wavelengths between 340 and 640 nm by a behavioral perimetric technique. Within this spectral range the mean spectral sensitivity of both fields was found to be maximal at 584 nm and minimal at the lower ultraviolet wavelengths. Differences in sensitivity were found, however, at shorter wavelengths, with the yellow field being more sensitive than the red at wavelengths below 500 nm and especially in the ultraviolet spectral range. These sensitivity differences are discussed in relation to other functional differences between the pigeon's retinal fields.

[Selective IgA deficiency, DPH-treated epilepsy and polyarthritis (author's transl)]

A selected IgA deficiency was found in a 66 years old, DPH-treated epileptic female, suffering from polyarthritis. Familial survey brings information for genetic transmission of IgA decreased concentrations in her offspring, unrelated with HLA A, B, C system.