Evaluation of Staining-Dependent Colour Changes in Resin Composites Using Principal Component Analysis.

Colour changes in Gradia Direct™ composite after immersion in tea, coffee, red wine, Coca-Cola, Colgate mouthwash, and distilled water were evaluated using principal component analysis (PCA) and the CIELAB colour coordinates. The reflection spectra of the composites were used as input data for the PCA. The output data (scores and loadings) provided information about the magnitude and origin of the surface reflection changes after exposure to the staining solutions. The reflection spectra of the stained samples generally exhibited lower reflection in the blue spectral range, which was manifested in the lower content of the blue shade for the samples. Both analyses demonstrated the high staining abilities of tea, coffee, and red wine, which produced total colour changes of 4.31, 6.61, and 6.22, respectively, according to the CIELAB analysis. PCA revealed subtle changes in the reflection spectra of composites immersed in Coca-Cola, demonstrating Coca-Cola's ability to stain the composite to a small degree.

Biocompatibility of new nanostructural materials based on active silicate systems and hydroxyapatite: in vitro and in vivo study.

AIM: To evaluate in vitro cytotoxicity and in vivo inflammatory response to new nanostructural materials based on active calcium silicate systems (CS) and hydroxyapatite (HA-CS). METHODOLOGY: Cytotoxicity of eluates of new nanostructural noncommercial materials CS and HA-CS, and MTA (White MTA, Angelus(®) Soluções Odontológicas, Londrina, Brazil) as a control, were tested using the MTT assay on MRC-5 cells. Eluates of set materials were tested in 100% and 50% concentrations, 24 h, 7 days and 21 days post-elution. The pH values were determined for undiluted eluates of set materials. Polyethylene tubes containing the test materials (CS, HA-CS, MTA) were implanted in subcutaneous tissue of Wistar rats. Histopathological examinations were conducted at 7, 15, 30 and 60 days after the implantation. Data were statistically analyzed using three-way and one-way anova Tukey's post hoc test as well as Kruskall-Wallis test with Dunn's post hoc test at α = 0.05. RESULTS: All materials significantly reduced cell viability; especially when undiluted eluates were used (P < 0.001). After 24 h elution, cell viability was 10 ± 1.8%, 49.5 ± 4.2% and 61 ± 7.4%, for MTA, and HA-CS, respectively. However, CS and HA-CS were significantly less toxic than the control material MTA (P < 0.05). Cytotoxicity could be at least partially attributed to pH kinetics over time. Dilution of eluates of all tested materials resulted in better cell survival. Histopathological examination indicated similar inflammatory reaction, vascular congestion and connective tissue integrity associated with CS, HA-CS and MTA at each observation period (P > 0.05). The only significant difference was found for capsule thickness, that is thicker capsule was associated with HA-CS compared to MTA at 60 days (P = 0.0039). HA-CS induced moderately thick capsules (median score 3, score range 2-3), whereas MTA resulted in thin capsule formation (median score 2, score range 1-3). CONCLUSIONS: Evaluation of cytotoxicity and inflammatory response indicated better biocompatibility of CS and HA-CS, in comparison with MTA (White MTA, Angelus(®) Soluções Odontológicas, Londrina, Brazil).

Management in child and adolescent psychiatry: how does it look in the Balkans?

This paper examines the situation of child and adolescent psychiatry in the following Balkan countries: Greece, Serbia, Bulgaria, Romania, Bosnia and Herzegovina, FYROM, and Montenegro. With the exception of Greece, these countries are new democracies, with their mental health services in a transitional stage of organization. Overall, they have initiated programmes to move psychiatric care towards deinstitutionalization, developing outpatient infrastructures to handle psychiatric disorders. Child psychiatry as a specialization is still less developed than adult psychiatry at a significant, albeit different degree among these countries. The number of mental health services offered to children and adolescents is deemed insufficient, and the type of services limited and lacking. This situation is also reflected in the small number of child psychiatrists and other mental health specialists for children and adolescents, as well as in the complete lack (Montenegro) or deficiency of special programmes and actions for children and adolescents. The same also applies to mental health legislation. Greece is the exception in the development of the entire spectrum of services, the number of specialists, and the establishment of an adequate legislation framework reinforced by the incorporation of all international treaties on children's rights; although the recent economic crisis has affected the country negatively, threatening with regression to pre-reformational practices. Children and adolescents in need of mental health care have been increasing in all countries. The effect of violent and sudden changes taking place in most countries is a major factor for the emergence of increased and stress-related psychopathology and psychosocial problems in children and families. In all countries, there is a significant development of nongovernmental organizations undertaking a large part of reformation work. There is also the disconcerting phenomenon of professional exhaustion and the migration of experts from their countries. Finally, there is the common need to develop educational programmes and related clinical practices in all degrees of prevention, promoting interdisciplinary cooperation, the biopsychosocial approach to understanding and dealing with mental health issues, as well as the development of cooperation among all institutions concerning children (education, health, etc.). All this should be reflected in a national plan to promote child mental health as the foundation upon which the necessary cooperation among Balkan countries would be established in order to promote research, the exchange of experiences, common practices, mutual understanding, and common interests.

Effect of evaporation on the shelf life of a universal adhesive.

OBJECTIVES: The purpose of this study was to evaluate how evaporation affects the shelf life of a one-bottle universal adhesive. METHODS: Three different versions of Scotchbond Universal (SBU, 3M ESPE, Seefeld, Germany) were prepared using a weight-loss technique. SBU0 was left open to the air until maximal weight loss was obtained, whereas SBU50 was left open until 50% of evaporation occurred. In contrast, SBU100 was kept closed and was assumed to contain the maximum concentration of all ingredients. The degree of conversion (DC) was determined by using Fourier transform infrared spectroscopy on different substrates (on dentin or glass plate and mixed with dentin powder); ultimate microtensile strength and microtensile bond strength to dentin were measured as well. RESULTS: DC of the 100% solvent-containing adhesive (SBU100) was higher than that of the 50% (SBU50) and 0% (SBU0) solvent-containing adhesives for all substrates. DC of the adhesive applied onto glass and dehydrated dentin was higher than that applied onto dentin. Even though the ultimate microtensile strength of SBU0 was much higher than that of SBU50 and SBU100, its bond strength to dentin was significantly lower. CONCLUSIONS: Evaporation of adhesive ingredients may jeopardize the shelf life of a one-bottle universal system by reducing the degree of conversion and impairing bond strength. However, negative effects only became evident after more than 50% evaporation.

New type of single chain magnet: pseudo-one-dimensional chain of high-spin Co(II) exhibiting ferromagnetic intrachain interactions.

Two new six-coordinated high-spin Co(II) complexes have been synthesized through the reactions of Co(II) salts with dipyridylamine (dpamH) and 5-nitro-salicylaldehyde (5-NO2-saloH) or 3-methoxy-salicylaldehyde (3-OCH3-saloH) under argon atmosphere: [Co(dpamH)2(5-NO2-salo)]NO3 (1) and [Co(dpamH)2(3-OCH3-salo)]NO3·1.3 EtOH·0.4H2O (2). According to the crystal packing of compound 1, two coordination cations are linked with two nitrate anions into a cyclic dimeric arrangement via N-H···O and C-H···O hydrogen bonds. In turn, these dimers are assembled into (100) layers through π-π stacking interactions between inversion-center related pyridine rings of the dpamH ligands. The crystal packing of compound 2 reveals a 1D assembly consisting solely from the coordination cations, which is formed by π-π stacking interactions between pyridine rings of one of the dpamH along the [010] and another 1D assembly of the coordination cations and nitrate anions through the N-H···O hydrogen-bonding interactions along the [001] direction. All complexes were magnetically characterized, and a new approximation method was used to fit the magnetic susceptibility data in the whole temperature range 2-300 K on the basis of an empirical expression which allows the treatment of each cobalt(II) ion in axial symmetry as an effective spin S(eff) = 1/2. In zero-field, dynamic magnetic susceptibility measurements show slow magnetic relaxation below 5.5 K for compound 2. The slow dynamics may originate from the motion of broad domain walls and is characterized by an Arrhenius law with a single energy barrier Δr/k(B) = 55(1) K for the [10-1488 Hz] frequency range. In order to reveal the importance of the crystal packing in the SCM behavior, a gentle heating process to 180 °C was carried out to remove the solvent molecules. The system, after heating, undergoes a major but not complete collapse of the network retaining to a small percentage its SCM character.

Clinical reproducibility of three electronic apex locators.

AIM: To compare the reproducibility of three electronic apex locators (EALs), Dentaport ZX, RomiApex A-15 and Raypex 5, under clinical conditions. METHODOLOGY: Forty-eight root canals of incisors, canines and premolars with or without radiographically confirmed periapical lesions required root canal treatment in 42 patients. In each root canal, all three EALs were used to determine the working length (WL) that was defined as the zero reading and indicated by 'Apex', '0.0' or 'red square' markings on the EAL display. A new K-file of the same size was used for each measurement. The file length was fixed with a rubber stop and measured to an accuracy of 0.01 mm. Measurements were undertaken by two calibrated operators. Differences in zero readings between the three EALs in the same root canal were statistically analysed using paired t-tests with the Bonferroni correction, Bland-Altman plot and Linn's concordance correlation coefficients at α = 0.05. RESULTS: Mean and standard deviation values measured by the three EALs showed no statistically significant differences. Identical readings by all three EALs were found in 10.4% of root canals. Forty-three per cent of readings differed by less than ± 0.5 mm and 31.3% exceeded a difference of ± 1 mm. CONCLUSIONS: The clinical reproducibility of Dentaport ZX, RomiApex A-15 and Raypex 5 was confirmed with the majority of readings within the ± 1.0 mm range. However, the small number of identical zero readings suggests that EALs are not reliable as the sole means of WL determination under clinical conditions.

Changes in calcineurin message, enzyme activity and protein content in the spinal dorsal horn are associated with chronic constriction injury of the rat sciatic nerve.

Plasticity in the spinal dorsal horn is thought to underlie the development of neuropathic pain. Calcineurin (protein phosphatase 3) plays an important role in plasticity in the brain. Here we examined whether chronic constriction injury (CCI) of the sciatic nerve modifies calcineurin expression in the spinal dorsal horn. Male rats were assigned to control (uninjured), sham-operated or CCI groups. CCI animals exhibited both a shift in weight bearing and a reduction in paw withdrawal latencies as signs of pain behavior. At 3 days (3D) the pain behavior was associated with a significant increase in calcineurin gene expression, enzyme activity and content of its Aα isoform in the ipsilateral spinal dorsal horn. In contrast, while the pain behavior persisted at 7 days (7D) calcineurin gene expression returned to control levels and activity and protein content decreased. A single intrathecal injection of MK-801 15 min before the ligation attenuated both signs of pain behavior in 3D but not 7D CCI animals. The same pre-treatment also prevented the CCI-associated increases in calcineurin in these animals. These data suggested an involvement of calcineurin in CCI-elicited neuropathic pain. The time-dependent divergent changes in calcineurin expression may underlie the different phases of neuropathic pain development.

Psychotropic medication use in children and adolescents in an inpatient setting.

Medication can be an effective part of treatment for several psychiatric disorders of childhood and adolescence but its use should be based on a comprehensive psychiatric evaluation and treatment plan. The aim of this study was to evaluate psychotropic medication use for children and adolescents treated as inpatients and to compare it with principles of rational pharmacotherapy, thus identifying possible downsides of current practices and pointing a way towards safer and more efficient practices. This is a descriptive study of prescribing trends at the Clinical Department for Children and Adolescents of the Institute of Mental Health in Belgrade, during the period from September 2009 to September 2010. Analyzed demographic data (age, gender) and the number of hospitalizations were obtained from medical histories, while diagnoses were obtained from discharge notes. Prescribed therapy was copied from medication charts. Drug dosages were analyzed as average daily doses prescribed during the hospitalization. Psychiatric diagnoses were classified according to The International Classification of Diseases and Related Health Problems, 10th Revision (ICD-10). During the examined time period, 264 patients were hospitalized (61.4% males), with an average age of 11.4±5.1 years. We have found that 66.3% of admitted patients were treated with pharmacotherapy in addition to other treatment modalities. There was a highly significant correlation between the age of patients and the prescribed dosage (Spearman's rho=0.360, p<0.001) as well as the number of prescribed drugs (Spearman's rho=0.405, p<0.001). The most commonly diagnosed psychiatric disorders were: autism spectrum disorders (20.8%), conduct disorders(19.7%), mixed developmental disorder (14.8%), adjustment disorder (7.2%), mental retardation (7.2%),acute psychosis (4.5%), and ADHD (2.3%). The most commonly prescribed medications were antipsychotics(45.9%), followed by antidepressants (17.2%), mood stabilizers (16.1%), benzodiazepines (14.4%), and other psychotropic drugs (6.4%). The most commonly prescribed antipsychotic was risperidone, used for more than 50% of the patients treated with antipsychotics. Taken together risperidone and chlorpromazine were more than 75% of all prescribed antipsychotics. 98.4% of prescribed antidepressants belonged to the SSRIs,with sertraline and fluoxetine accounting for almost 90% of them. All prescribed dosages were in accordance with the official guidelines. This is the first survey in Serbia to document the practice of prescribing psychotropic medication in the field of child and adolescent psychiatry. Current drug-prescribing practices at the Clinical Department for Children and Adolescents of the Institute of Mental Health in Belgrade are in accordance with current practices in the United States and Europe. Not every child with symptoms of mental health problems needs pharmacological treatment; when they do, the general rule of thumb should be "start low, go slow, and taper slowly". Follow-up studies are necessary to assess the change of trends, as well as studies in different patient populations and health centers, in order to globally evaluate psychotropic medication use in children and adolescents in Serbia.

Temperature rise within the pulp chamber during composite resin polymerisation using three different light sources.

UNLABELLED: The purpose of the study was to compare temperature rise during polymerisation of resin based composites (RBCs) with two LED light curing units (LCUs) compared to a halogen control light. METHODS: Forty-five extracted molars, patients aging 11-18 years were used. Thermocouples (TCs) were placed in contact with the roof of the pulp chamber using a 'split-tooth' method. Teeth were placed in a water bath with the temperature of the pulp chamber regulated at 37 degrees +/-1 degrees C. GROUP 1 (CONTROL): Prismatics((R)) Lite II (Dentsply Detrey, Konstanz, Germany), a halogen LCU, light intensity 500 mW/cm(2). GROUP 2: Bluephase((R)) ( Ivoclar Vivadent, Schaan, Liechtenstein), light intensity 1100 mW/cm(2). Group 3:Elipar Freelight2 (3M ESPE, Seefeld, Germany), light intensity 1000 mW/cm(2). Temperature changes were continuously recorded with a data logger connected to a PC. RESULTS: Significantly higher temperature rise was recorded during bond curing than RBC curing in all 3 groups. (Halogen; p =0.0003: Bluephase; p=0.0043: Elipar; p=0.0002.). Higher temperatures were recorded during polymerisation of both Bond and RBC with both LED sources than with the halogen control. There was no significant difference between the two LED,LCUs (Bond:p=0.0279: RBC p=0.0562: Mann-Whitney). CONCLUSION: The potential risk of pulpal injury during RBC polymerisation is increased when using light-curing units with high energy output compared to low energy output light sources. The rise is greatest when curing bonding agent alone and clinicians are advised to be aware of the potential hazard of thermal trauma to the pulp when using high intensity light sources. However the mean temperature rise with all three units was below the limits normally associated with permanent pulp damage.

La infusión sistémica continua de lidocaína proporciona analgesia en un modelo animal de dolor neuropático / Continual systemic infusion of lidocaine provides analgesia in an animal model of neuropathic pain

La finalidad de este estudio fue determinar si la infusión continua a velocidad constante de lidocaína proporcionaba analgesia durante la fase inicial posterior a la lesión en el modelo de dolor neuropático causado por lesión por constricción crónica. Ratas Sprague-Dawley macho se dividieron en grupos de control y ligadura y recibieron una infusión con solución salina fisiológica o lidocaína (0,15, 0,33, 0,67 y 1,3 mg . k g- 1. h- 1) por medio de minibombas osmóticas Alzet® implantadas subcutáneamente. Se obtuvieron las latencias de retirada ante estímulos términos antes (día 0) y 3 días después de realizar una ligadura floja del nervio ciático e implantar la bomba. Los animales sometidos a ligadura que estaban recibiendo lidocaína con una velocidad de infusión de 0,67 ó 1,3 mg.kg- 1. h- 1 no exhibieron ningún cambio en la latencia de retirada el día 3 después de la cirugía, lo que indica que la lidocaína a esas dosis previno la aparición de hiperalgesia térmica como manifestación de dolor neuropático. Por el contrario, los animales sometidos a ligadura y tratados con solución salina fisiológica o lidocaína con una velocidad de infusión de 0,15 ó 0,33 mg.kg- 1. h- 1 exhibieron hiperalgesia el día 3 después de la cirugía, lo que indica que esas dosis más pequeñas de lidocaína no proporcionaron analgesia. Los animales de control tratados con solución salina fisiológica o con cualquiera de las dosis de lidocaína no exhibieron ningún cambio en las latencias de retirada entre el día 0 y el día 3. En otro grupo de animales sometidos a ligadura, la infusión de lidocaína (0,67 mg.kg- 1. h- 1) iniciada 24 horas después de la intervención quirúrgica para ligar el nervio ciático suprimió la hiperalgesia térmica ya presente. Las concentraciones plasmáticas medidas de lidocaína fueron de 0,11, 0,36 y 0,45 µg.ml- 1 en los animales que recibieron 0,33, 0,67 y 1,3 mg- 1. k g . h- 1 de lidocaína, respectivamente. Estos resultados sugieren que la infusión sistémica continua de lidocaína previene o revierte la aparición de dolor neuropático después de una lesión crónica por constricción. Estos resultados se suman a las evidencias cada vez más numerosas del valor terapéutico de la administración preventiva y postoperatoria de lidocaína para el alivio del dolor neuropático. (AU)

Changes in post-tetanic potentiation of A-fiber dorsal horn field potentials parallel the development and disappearance of neuropathic pain after sciatic nerve ligation in rats.

Significant plastic changes in spinal nociceptive processing appear to accompany peripheral nerve injury or inflammation. Using a well-established model of neuropathic pain, we have recently reported that loose ligation of the sciatic nerve was accompanied by a long-lasting post-tetanic potentiation of sciatic-evoked A-fiber superficial dorsal horn field potentials. In the present study we demonstrate that the typical disappearance of thermal hyperalgesia as a behavioral sign of neuropathic pain several weeks after loose sciatic nerve ligation is accompanied by the loss of the long-lasting potentiation. These data suggest that a significant but reversible shift in the processing of sensory information in the spinal dorsal horn follows peripheral nerve injury, and lend further support to the notion that long-lasting synaptic plasticity may contribute to the development of neuropathic pain.

Contribution of GABA-A receptors to metaplasticity in the spinal dorsal horn.

Metaplasticity is a higher-order form of synaptic plasticity that is induced by synaptic or cellular activity, which by itself may not produce changes in synaptic strength, but which modifies subsequent changes in synaptic efficacy. In this description of metaplasticity in the spinal dorsal horn, we report that a 50 Hz high-frequency tetanus, previously shown to elicit a potentiation of sciatic-evoked A-fiber spinal dorsal horn potentials, caused a depression when coupled with a more rapid rate of repetitive stimulation. This depression appeared to be dependent upon GABA(A) receptor activation because the 50 Hz tetanus elicited a persistent potentiation when the GABA(A) antagonist bicuculline was injected at 1 mg/kg (but not at 0.5 mg/kg) prior to tetanic stimulation. These data suggest the presence of strong inhibitory inputs in the spinal dorsal horn that are activated by an increased rate of primary afferent firing. The activation of these inputs may be necessary to prevent prolonged bursts of afferent activity from modifying synaptic strength because the latter may contribute to the development of persistent pain following peripheral nerve injury.

Differential effects of inorganic lead on hippocampal long-term potentiation in young rats in vivo.

Tetanic stimulation at 50 Hz elicited long-term potentiation (LTP) in the hippocampal CA1 region of 28-day-old control animals. In contrast, no significant potentiation was seen following the same tetanus in animals chronically exposed to 1000 ppm of lead acetate during development. Gender differences were observed in animals exposed to 500 ppm of lead. In females, LTP was significantly attenuated, while in males the LTP was identical to that of controls.

Increased spinal monoamine concentrations after chronic thoracic dorsal rhizotomy in goats.

In goats, bilateral thoracic dorsal rhizotomy (TDR) causes severe ventilatory failure during exercise, followed by progressive functional recovery. We investigated spinal neurochemical changes associated with TDR and/or functional recovery by measuring spinal concentrations of the monoamines serotonin (5-HT), norepinephrine, and dopamine via HPLC. Changes in 5-HT and calcitonin gene-related peptide were visualized with immunohistochemistry. Goat spinal cords were compared 4-15 mo after TDR from T(2) to T(12) (n = 7) with sham-operated (n = 4) or unoperated controls (n = 4). TDR increased the concentration of cervical 5-HT (C(5)-C(6); 122% change), caudal thoracic norepinephrine (T(7)-T(11); 53% change), and rostral thoracic dopamine (T(3)-T(6); 234% change). TDR increased 5-HT-immunoreactive terminal density (dorsal and ventral horns) and nearly eliminated calcitonin gene-related peptide immunoreactivity in the superficial laminae of the dorsal horn in rostral thoracic segments; both effects became less pronounced in caudal thoracic segments. Thus TDR elevates monoamine concentrations in discrete spinal regions, including possible compensatory changes in descending serotonergic inputs to spinal segments not directly affected by TDR (i.e., cervical) but associated with functionally related motor nuclei (i.e., phrenic nucleus).

Loose ligation of the rat sciatic nerve is accompanied by changes in the subcellular content of protein kinase C beta II and gamma in the spinal dorsal horn.

This study examined whether loose ligation of the sciatic nerve was accompanied by specific changes in protein kinase C (PKC) betaII and gamma isozymes in the spinal dorsal horn. The isozyme staining pattern was visualized with immunocytochemistry. Their content in subcellular fractions was estimated from Western immunoblots. In control animals, PKC betaII immunoreactivity extended from lamina I into lamina III, while PKC gamma immunoreactivity was concentrated within laminae II and III. In ligated animals exhibiting thermal hyperalgesia, the content of both PKC betaII and gamma in the synaptosomal membrane fraction, but not crude cytosolic fraction, was significantly greater by an average of 40% from their respective controls. These data support suggestions that peripheral nerve injury engenders plastic changes in the dorsal horn to contribute to the development of persistent pain.

Long-term changes in sciatic-evoked A-fiber dorsal horn field potentials accompany loose ligation of the sciatic nerve in rats.

The goal of the present study was to examine whether loose ligation of the sciatic nerve was associated with long-term changes in neuronal excitability in the spinal dorsal horn in urethane-anesthetized rats. The sciatic nerve was stimulated with 0. 1 ms long pulses at 1 stimulus/5 min, and the evoked dorsal horn field potentials remained stable in the absence of tetanic stimulation. In one set of control and ligated animals, high-frequency tetanic stimulation was applied to the nerve at 50 Hz (one 400 ms train of twenty 0.1 ms pulses), and the field potentials were recorded again (1 stimulus/5 min) for up to 4 h post-tetanus. In control animals, this protocol produced significant increases in field potential amplitudes at 15, 30 and 60 min post-tetanus. Interestingly, after this time the evoked field potentials began to decrease, and attained less than 50% of their pre-tetanic values at 240 min post-tetanus. In contrast, in ligated rats the pattern of post-tetanic potentiation was significantly different as the increases in amplitude persisted, and at 240 min post-tetanus the field potentials were almost twice their baseline values. In another set of control and ligated animals, low-frequency tetanic stimulation was applied at 5 Hz (one 400 ms train of two 0.1 ms pulses). Again a differential pattern of post-tetanic responses between control and ligated rats was seen. In control animals, a significant decrease in amplitude was evident within 30 min, and the depression became progressively more pronounced as the field potentials attained about a quarter of their baseline values at 180 min, and remained at these low levels at 240 min post-tetanus. On the other hand, in ligated animals, the depression was not significant, and at 240 min post-tetanus the field potentials were still at about 80% of their baseline values. These data demonstrate that long-term changes in spinal dorsal horn neuronal excitability accompany sciatic ligation to perhaps contribute to the development of neuropathic pain. These changes may result from a lessening of normally strong inhibitory processes in the spinal dorsal horn to generate conditions which favor post-tetanic potentiation over depression of dorsal horn neuronal responses.

Immunoglobulin in the control of complement action.

Complement is a critical element of innate immunity, protecting individuals from a wide variety of microbial infections. This group of proteins is responsible for many features of inflammation and tissue damage. Because of its ability to mediate autoimmune tissue damage and to destroy host tissues, it is under tight regulation with many circulating and cell-membrane-bound complement regulatory proteins. The function of much of the circulating immunoglobulin has never been defined. We have advanced the hypothesis that one function of circulating immunoglobulin is to down-regulate complement attack on host tissues in the presence of anti-self antibody. The data to support this hypothesis are reviewed. The data are consistent with the suggestion that one mechanism of action of intravenous immunoglobulin, used to treat patients with a variety of autoimmune diseases, is prevention of complement-mediated attack on host tissues.

Chronic exposure to lead acetate affects the development of protein kinase C activity and the distribution of the PKCgamma isozyme in the rat hippocampus.

This study has examined the effect of chronic inorganic lead exposure on phospholipid-dependent protein kinase C (PKC) activity, and the distribution of its alpha (alpha), beta II (betaII), gamma (gamma), and zeta (zeta) isozymes in subcellular fractions of the developing rat hippocampus. Dams were exposed to either 0 or 1000 ppm lead acetate in their drinking water for one week and mated. Offspring were exposed to lead in utero, via lactation, and directly in the drinking water after weaning. The offspring were sacrificed at postnatal days 1 (P1), 8 (P8), 15 (P15), and 29 (P29). PKC activity was determined in the post-synaptosomal supernatant (PSS) and synaptosomal (P-2) membrane fractions by an in vitro assay using histone as the phosphate acceptor. The selected PKC isozymes were detected by immunoblotting techniques. In control animals, PKC activity (pmole/min/mg total protein) in both subcellular fractions substantially increased between P1 and P8. In chronically exposed rats exhibiting clinically relevant blood lead concentrations, this marked increase in PKC activity on P8 was significantly attenuated in both subcellular fractions. On this postnatal day, the amount of immunodetectable PKC gamma was significantly higher in the synaptosomal membrane fraction of lead-exposed rats. Other isozymes were unaffected. These results imply that in lead-exposed animals the PKC gamma isozyme was inactive even though it was associated with the membrane. These results also suggest that prolonged exposure to the heavy metal attenuated PKC activity at an important developmental time to potentially adversely affect normal hippocampal function.

A technique for evaluating analgesia in conscious perching birds.

OBJECTIVE: To develop a technique for objective assessment of modulation of nociperception in conscious perching birds. ANIMALS: 31 adult African grey parrots. PROCEDURE: Birds were randomly assigned to receive saline (0.9% NaCl) solution (n = 10), butorphanol tartrate (11), or buprenorphine hydrochloride (10), i.m. Birds were fitted with a surface electrode on the medial metatarsus of 1 leg. An electrical stimulus was delivered to the bird's foot through an aluminum surface on half of the perch. The alternate side of the perch delivered a noxious thermal stimulus. A withdrawal response to either stimulus was recorded when the bird lifted its foot or vigorously flinched its wings. RESULTS: Responses to thermal stimuli were extremely variable during baseline testing and after administration of drugs. Thus, significant differences were not detected after drug injection. In contrast, responses to an electrical stimulus were predictable with much less variation. CONCLUSIONS AND CLINICAL RELEVANCE: This method and device allowed for the reliable determination of withdrawal threshold in perching birds. Use of this technique for objective assessment of modulation of nociperception in conscious perching birds will enable assessment of analgesic drugs.

Analgesic effects of butorphanol and buprenorphine in conscious African grey parrots (Psittacus erithacus erithacus and Psittacus erithacus timneh).

OBJECTIVE: To evaluate effects of butorphanol tartrate and buprenorphine hydrochloride on withdrawal threshold to a noxious stimulus in conscious African grey parrots. ANIMALS: 29 African grey parrots (Psittacus erithacus erithacus and Psittacus erithacus timneh). PROCEDURE: Birds were fitted with an electrode on the medial metatarsal region of the right leg, placed into a test box, and allowed to acclimate. An electrical stimulus (range, 0.0 to 1.46 mA) was delivered to each bird's foot through an aluminum perch. A withdrawal response was recorded when the bird lifted its foot from the perch or vigorously flinched its wings. Baseline threshold to a noxious electrical stimulus was determined. Birds then were randomly assigned to receive an i.m. injection of saline (0.9% NaCl) solution, butorphanol (1.0 mg/kg of body weight), or buprenorphine (0.1 mg/kg), and threshold values were determined again. RESULTS: Butorphanol significantly increased threshold value, but saline solution or buprenorphine did not significantly change threshold values. CONCLUSIONS AND CLINICAL RELEVANCE: Butorphanol had an analgesic effect, significantly increasing the threshold to electrical stimuli in African grey parrots. Buprenorphine at the dosage used did not change the threshold to electrical stimulus. Butorphanol provided an analgesic response in half of the birds tested. Butorphanol would be expected to provide analgesia to African grey parrots in a clinical setting.