Continuous Flow Microfluidic Production of Arbitrarily Long Tubular Liquid Crystal Elastomer Peristaltic Pump Actuators

While liquid crystal elastomers (LCEs) are ideal materials for soft-robotic actuators, filling the role of muscle and shape-defining material simultaneously, it is non-trivial to give them ground state shapes beyond simple sheets or fibers. Here tubular LCE actuators scalable to arbitrary length are produced using a continuous three-phase coaxial flow microfluidic process. By pumping an oligomeric precursor solution between inner and outer aqueous phases in a cylindrically symmetric nested capillary set-up, and by reducing the interfacial tension to negligible values using surfactants adapted to each phase, the tubular liquid flow is stabilized over distances more than 200 times the diameter or 2000 times the thickness. In situ photocrosslinking of the middle phase turns it into an LCE network that is flow-aligned by the shear gradient over the phase. The reversible actuation of the tubes upon heating yields a reduction of the interior space, pumping out enclosed fluid, and the relaxation upon cooling leads to the fluid being sucked back in. By moving a local heat source along the tube, it acts as a peristaltic pump. It is proposed that the tubes could, pending functionalization for light-triggered actuation, function as active synthetic vasculature in biological contexts.

PATIENTS' OPINIONS ON OUTPATIENT MEDICAL CARE DURING THE COVID-19 CRISIS

COVID-19 was a challenge which tested the entirety of our country's healthcare system from 2020-2021. The pandemic was an emergency, quite dynamic, and necessitated quick and thoughtful actions. Ever since the official announcement of the COVID-19 pandemic in Bulgaria and the first reported cases from 08.03.2020 to 30.09.2020, the total number of registered cases has risen to 500112. This fact was the reason we conducted a survey among 531 patients from all over the country regarding the changes in their access to the doctor's office and the methods they used for contacting their general practitioner for the period from March 2020 to April 2021.The results show that over 51.41% of participants have seen an improvement in their access to their GP's office due to the fewer patients visiting the office. At the same time, 42.18% of participants reported they received phone consults or had their phone calls returned during their general practitioner's working hours. 26.18% of respondents have received phone consults regardless of the time. 30.70% of respondents have communicated with their GP via Viber; 14.50% via messenger; 6.03% via email.

Identification of serum microRNA signatures associated with autism spectrum disorder as promising candidate biomarkers

Background

MicroRNAs (miRNAs) are short non-coding RNA molecules with a well-recognized role in gene expression mostly at the post-transcriptional level. Recently, dysregulation of miRNAs and miRNA-mRNA interactions has been associated with CNS diseases, including numerous psychiatric disorders. Dynamic changes in the expression profiles of circulating miRNA are nowadays regarded as promising non-invasive biomarkers that may facilitate the accurate and timely diagnosis of complex conditions.

Methods

In this study, we investigated the gene expression patterns of four miRNAs, which were previously reported to be dysregulated in pooled serum samples taken from Autism Spectrum Disorder (ASD) patients and typically developing children. The performance of a diagnostic model for ASD based on these four miRNAs was assessed by a receiver operating characteristic (ROC) curve analysis, which evaluates the diagnostic accuracy of the investigated miRNA biomarkers for ASD. Finally, to examine the potential modulation of CNS-related biological pathways, we carried out target identification and pathway analyses of the selected miRNAs.

Results

Significant differential expression for all the four studied miRNAs: miR-500a-5p, miR-197-5p, miR-424-5p, and miR-664a-3p, was consistently measured in the samples from ASD patients. The ROC curve analysis demonstrated high sensitivity and specificity for miR-500a-5p, miR-197-5p, and miR-424-5p. With all miRNA expression data integrated into an additive ROC curve, the combination of miR-500a-5p and miR-197-5p provided the most powerful diagnostic model. On the other hand, the mRNA target mining showed that miR-424-5p and miR-500-5p regulate pools of target mRNA molecules which are enriched in a number of biological pathways associated with the development and differentiation of the nervous system.

Conclusions

The steady expression patterns of miR-500a-5p, miR-197-5p, miR-424-5p, and miR-664a-3p in ASD children suggest that these miRNAs can be considered good candidates for non-invasive molecular biomarkers in the study of ASD patients. The highest diagnostic potential is manifested by miR-500a-5p and miR-197-5p, whose combined ROC curve demonstrates very strong predictive accuracy.

Clinoptilolite Microparticles as Carriers of Catechin-Rich Acacia catechu Extracts: Microencapsulation and In Vitro Release Study

The main goal of the present study was to investigate the microencapsulation, in vitro release capacity and efficiency of catechin-rich Acacia catechu extract by Clinosorbent-5 (CLS-5) microparticles by in-depth detailed analyses and mathematical modelling of the encapsulation and in vitro release kinetics behaviour of the polyphenol-mineral composite system. The bioflavanol encapsulation and release efficiency on/from the mineral matrix were assessed by sorption experiments and interpretative modelling of the experimental data. The surface and spectral characteristics of the natural bioactive substance and the inorganic microcarrier were determined by Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet/Visible (UV/Vis) spectrophotometric analyses. The maximum extent of catechin microencapsulation in acidic medium was 32%. The in vitro release kinetics study in simulated enzyme-free gastric medium (pH = 1.2) approved 88% maximum release efficiency achieved after 24 h. The in vitro release profile displayed that the developed bioflavanol/clinoptilolite microcarrier system provided sustained catechin in vitro release behaviour without an initial burst effect. Thus, the results from the present study are essential for the design and development of innovative catechin-CLS-5 microcarrier systems for application in human and veterinary medicine.

EZH2 mutations are frequent and represent an early event in follicular lymphoma

Gain of function mutations in the H3K27 methyltransferase EZH2 represent a promising therapeutic target in germinal center lymphomas. In this study, we assessed the frequency and distribution of EZH2 mutations in a large cohort of patients with follicular lymphoma (FL) (n = 366) and performed a longitudinal analysis of mutation during the disease progression from FL to transformed FL (tFL) (n = 33). Mutations were detected at 3 recurrent mutation hot spots (Y646, A682, and A692) in 27% of FL cases with variant allele frequencies (VAF) ranging from 2% to 61%. By comparing VAF of EZH2 with other mutation targets (CREBBP, MLL2, TNFRSF14, and MEF2B), we were able to distinguish patients harboring clonal EZH2 mutation from rarer cases with subclonal mutations. Overall, the high incidence of EZH2 mutations in FL and their stability during disease progression makes FL an appropriate disease to evaluate EZH2 targeted therapy.

Interplay between Homeobox proteins and Polycomb repressive complexes in p16INK⁴a regulation

The INK4/ARF locus regulates senescence and is frequently altered in cancer. In normal cells, the INK4/ARF locus is found silenced by Polycomb repressive complexes (PRCs). Which are the mechanisms responsible for the recruitment of PRCs to INK4/ARF and their other target genes remains unclear. In a genetic screen for transcription factors regulating senescence, we identified the homeodomain-containing protein HLX1 (H2.0-like homeobox 1). Expression of HLX1 extends cellular lifespan and blunts oncogene-induced senescence. Using quantitative proteomics, we identified p16(INK4a) as the key target mediating the effects of HLX1 in senescence. HLX1 represses p16(INK4a) transcription by recruiting PRCs and HDAC1. This mechanism has broader implications, as HLX1 also regulates a subset of PRC targets besides p16(INK4a). Finally, sampling members of the Homeobox family, we identified multiple genes with ability to repress p16(INK4a). Among them, we found HOXA9 (Homeobox A9), a putative oncogene in leukaemia, which also recruits PRCs and HDAC1 to regulate p16(INK4a). Our results reveal an unexpected and conserved interplay between homeodomain-containing proteins and PRCs with implications in senescence, development and cancer.

Modified natural clinoptilolite detoxifies small mammal's organism loaded with lead I. Lead disposition and kinetic model for lead bioaccumulation

Zeolites, especially clinoptilolites, have wide application in removing heavy metals from different solutions and wastewater. The detoxification capacity of the clinoptilolite sorbent KLS-10-MA, a modified natural Bulgarian zeolite, applied as a food supplement in conditions of an ecotoxicological experiment with conventional food and lead was demonstrated for the first time. Laboratory mice, inbred imprinting control region strain, were used in a 90-day ecotoxicological experiment. Animals were divided into four experimental groups. Lead bioaccumulations in exposed and non-supplemented/supplemented with KLS-10-MA animals were compared. As additional control, healthy animals non-exposed to Pb were fed with conventional forage mixed with 12.5% KLS-10-MA. The dietary inclusion of the sorbent reduced Pb concentrations in exposed and supplemented mice by 84%, 89%, 91%, 77%, and 88% in carcass, liver, kidneys, bones, and feces, respectively. A mathematical model was proposed to outline the common trends of bone Pb bioaccumulation in exposed and non-supplemented/supplemented animals. Characteristic parameters of the kinetics of Pb concentrations were determined. Based on the model, the coefficient of absorption of Pb by gastrointestinal mucosa in the supplemented mice was found-η = 3.53% (versus η = 15% in non-supplemented ones). The present study clearly indicates that there is a realistic perspective to create a new drug based on modified natural clinoptilolites in cases of chronic heavy metal intoxication, without negatively affecting the environment.

Functional crosstalk between Bmi1 and MLL/Hoxa9 axis in establishment of normal hematopoietic and leukemic stem cells

Bmi1 is required for efficient self-renewal of hematopoietic stem cells (HSCs) and leukemic stem cells (LSCs). In this study, we investigated whether leukemia-associated fusion proteins, which differ in their ability to activate Hox expression, could initiate leukemia in the absence of Bmi1. AML1-ETO and PLZF-RARα, which do not activate Hox, triggered senescence in Bmi1(-/-) cells. In contrast, MLL-AF9, which drives expression of Hoxa7 and Hoxa9, readily transformed Bmi1(-/-) cells. MLL-AF9 could not initiate leukemia in Bmi1(-/-)Hoxa9(-/-) mice, which have further compromised HSC functions. But either gene could restore the ability of MLL-AF9 to establish LSCs in the double null background. As reported for Bmi1, Hoxa9 regulates expression of p16(Ink4a)/p19(ARF) locus and could overcome senescence induced by AML1-ETO. Together, these results reveal an important functional interplay between MLL/Hox and Bmi1 in regulating cellular senescence for LSC development, suggesting that a synergistic targeting of both molecules is required to eradicate a broader spectrum of LSCs.

Epigenetic regulation of the INK4b-ARF-INK4a locus: in sickness and in health

The INK4b-ARF-INK4a locus encodes for two cyclin-dependent kinase inhibitors, p15(INK4b) and p16(INK4a) and a regulator of the p53 pathway, ARF. In addition ANRIL, a non-coding RNA, is also transcribed from the locus. ARF, p15(INK4b) and p16(INK4a) are well-established tumor suppressors which function is frequently disabled in human cancers. Recent studies showed that single nucleotide polymorphisms mapping in the vicinity of ANRIL are linked to a wide spectrum of conditions, including cardiovascular disease, ischemic stroke, type 2 diabetes, frailty and Alzheimer's disease. The INK4b-ARF-INK4a locus is regulated by Polycomb repressive complexes (PRCs), and its expression can be invoked by activating signals. Other epigenetic modifiers such as the histone demethylases JMJD3 and JHDM1B, the SWI/SNF chromatin remodeling complex and DNA methyltransferases regulate the locus interplaying with PRCs. In view of the intimate involvement of the INK4b-ARF-INK4a locus on disease, to understand its regulation is the first step for manipulate it to therapeutic benefit.

Chemokine signaling via the CXCR2 receptor reinforces senescence

Cells enter senescence, a state of stable proliferative arrest, in response to a variety of cellular stresses, including telomere erosion, DNA damage, and oncogenic signaling, which acts as a barrier against malignant transformation in vivo. To identify genes controlling senescence, we conducted an unbiased screen for small hairpin RNAs that extend the life span of primary human fibroblasts. Here, we report that knocking down the chemokine receptor CXCR2 (IL8RB) alleviates both replicative and oncogene-induced senescence (OIS) and diminishes the DNA-damage response. Conversely, ectopic expression of CXCR2 results in premature senescence via a p53-dependent mechanism. Cells undergoing OIS secrete multiple CXCR2-binding chemokines in a program that is regulated by the NF-kappaB and C/EBPbeta transcription factors and coordinately induce CXCR2 expression. CXCR2 upregulation is also observed in preneoplastic lesions in vivo. These results suggest that senescent cells activate a self-amplifying secretory network in which CXCR2-binding chemokines reinforce growth arrest.

[Surgical diseases of thyroid gland]

Medical reports of 8,768 patients with various diseases of thyroid gland were analyzed. There were 1,563 (17.8) male and 7,201 (82.2%) female patients aged 6 to 86 years. One-nodular goiter was diagnosed at 13.85% patients, multinodular goiter - at 67.2%, diffuse toxic goiter - at 5.85%, thyreotoxic adenoma - at 4.91%, Hashimoto's thyroiditis - at 8.16% patients. Thyroid cancer was revealed at 1.56 patients with nodular goiter, at 8.45% - with multinodular goiter, at 2.72% - with diffuse toxic goiter, at 3.71% - with thyreotoxic adenoma, and at 27.09% patients with Hashimoto's thyroiditis. Totally thyroid cancer was diagnosed at 741 (8.45%) patients including 71.12% papillary cancer, 26.47% follicular cancer and 2.42% medullar (anablastic) cancer. Some patients had metastases. It is concluded that all the patients with goiter should be operated. At diffuse toxic goiter the surgical treatment is indicated at the patients with recurrences or after 6 - 12 months of conservative treatment without clinical improvement.

[Primary flexor tendon ruptures of the little finger within the carpal tunnel. Proposed classification based on six clinical cases and review of the literature]

Six cases of primary flexor tendon rupture of the little finger within the carpal tunnel are presented. All of them were attritional ruptures caused by a rough hook of the hamate. These ruptures are rare. They have their place among the flexor tendon ruptures of the wrist and the palm. Ultrasound may by helpful to determine the level of rupture. The surgical treatment consists of excision of the hook of the hamate and tendon repair.

Cytotoxicity and apoptotic effects of microcystin-LR and anatoxin-a in mouse lymphocytes

There is an increasing amount of knowledge on the cytotoxic properties of cyanotoxins, but relatively little is known regarding their fine specificity and mechanisms of action. In this study, we investigated the influence of microcystin-LR and AnTx-a on mouse B- and T-lymphocyte subpopulations in vitro. Cyanotoxins significantly decreased the cell viability after 4 and 24 h, compared to the untreated control. After 24 h exposure to microcystin-LR and anatoxin-a, the viability of splenocytes dropped to 23% and 57%, respectively. Our data demonstrate that microcystin-LR induced apoptosis specifically in mouse B cells, probably via the B-cell antigen receptor and mitochondrial pathway, while the T cells were not affected. AnTx-a showed cytotoxic effects on both lymphocyte subpopulations, but the effects were driven by mechanisms different from apoptosis. These findings demonstrate that the cyanotoxins could cause cytotoxic alterations in a variety of cell types different from the major targets, operating via distinct mechanisms.

Morphological, genetic and functional variability of a T-cell hybridoma line

The variability in the morphology, modal number of chromosomes, TCR expression and functional reactivity of a CII-specific T-cell hybridoma at continuous subcultivation have been investigated. As the number of passages increased, besides the oval semiadherent cells (normal phenotype), fibroblast-like cells (transformed phenotype) were also observed. The two cell subpopulations differed in their karyotype characteristic, as well as in their functional reactivity. The cell population with a normal phenotype was characterized by a tetramodal number of chromosomes (30, 40, 48 and 70) and trisomies of chromosomes 6 and 14, while the cell population with a transformed phenotype was characterized by a trimodal number of chromosomes (11, 68 and 74) and trisomy of chromosome 12. A nullisomy of sex chromosomes was established in both types of cells. In the initial passages of subcultivation, 73.04% of the cells with a normal morphological phenotype expressed TCR-CD3 complexes on their surface and possessed high functional reactivity. After a two-week subcultivation, the values of these indices went down considerably: 46.11% of the cells expressed functional TCR-CD3 complexes, as a result of which their functional reactivity decreased. Only 2.71% of the cells with a transformed morphological phenotype expressed functional TCR-CD3 complexes on their surface. In these cells, a total loss of reactivity towards the specific antigens was established. The achieved results show that at continuous subcultivation the T-cell hybridomas are unstable, and with the increase in the number of passages there appear chromosome rearrangements, leading to loss of their functional reactivity.

Switch from Myc/Max to Mad1/Max binding and decrease in histone acetylation at the telomerase reverse transcriptase promoter during differentiation of HL60 cells

Recent evidence suggests that the Myc and Mad1 proteins are implicated in the regulation of the gene encoding the human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase. We have analyzed the in vivo interaction between endogenous c-Myc and Mad1 proteins and the hTERT promoter in HL60 cells with the use of the chromatin immunoprecipitation assay. The E-boxes at the hTERT proximal promoter were occupied in vivo by c-Myc in exponentially proliferating HL60 cells but not in cells induced to differentiate by DMSO. In contrast, Mad1 protein was induced and bound to the hTERT promoter in differentiated HL60 cells. Concomitantly, the acetylation of the histones at the promoter was significantly reduced. These data suggest that the reciprocal E-box occupancy by c-Myc and Mad1 is responsible for activation and repression of the hTERT gene in proliferating and differentiated HL60 cells, respectively. Furthermore, the histone deacetylase inhibitor trichostatin A inhibited deacetylation of histones at the hTERT promoter and attenuated the repression of hTERT transcription during HL60 cell differentiation. In addition, trichostatin A treatment activated hTERT transcription in resting human lymphocytes and fibroblasts. Taken together, these results indicate that acetylation/deacetylation of histones is operative in the regulation of hTERT expression.

Assessment of left ventricular systolic function and diastolic time intervals by the bioimpedance polyrheocardiographic system

In order to detect left ventricular systolic function and diastolic time intervals using a new improved bioimpedance polyrheocardiographic system (BPCS), 110 healthy subjects and 128 patients with myocardial infarction were examined. Twenty-four simultaneous measurements of cardiac output by thermodilution and BPCS were performed in 11 patients with complicated acute left ventricular failure. Studies demonstrated a high degree of correlation (r = 0.91, p < 0.001). The correlation between the methods of using signals of the second derivative and the subtracted first derivative waveform of BPCS and continuous-wave Doppler echocardiography of systolic and diastolic time intervals was studies in 51 patients. The methods were closely correlated, especially with respect to left ventricular ejection time (r = 0.95), isovolumic relaxation time (r = 0.85), time to peak filling (r = 0.90), and deceleration of rapid filling time (r = 0.91). New bioimpedance hemodynamic parameters such as peak volume acceleration of ejection (PVAE) and peak power ejection (PPE) in patients with heart failure (NYHA Class I-III) were studied. Significant reductions of PVAE and PPE in groups of patients with marked progression of heart failure were noted. These results have demonstrated that BPCS is a noninvasive, simple accurate method of assessment of left ventricular systolic function and diastolic time intervals.

[A dental concept in gerontology]

The necessity of gerontal dental care programme will be caused by statistical datas. The mainpoints of this prophylactically orientated care programme are described.

Effects of intraventricularly applied gangliosides and N-acetylneuraminic acid on acquisition and retention performance of a brightness discrimination task in rats

The effects of intraventricularly applied gangliosides (about 90 to 120 nmoles/10 microliters) and N-acetylneuraminic acid (800 nmoles/10 microliters) on acquisition and retention of a brightness discrimination task were studied in rats. Single injection of GT1b and N-acetylneuraminic acid improved the retention performance. GM1 showed an enhancing effect on both acquisition and retention, while GD1a and GD1b exerted no influence on the behavioral parameters tested. The findings presented show how memory may be improved by exogenous application of substances commonly occurring in the mammalian body.

Influence of dopamine receptor agonists and antagonists on calmodulin translocation in different brain regions

Acute and chronic experiments were performed to study the effects of intraperitoneally administered dopamine receptor agonists and antagonists on the translocation of cytosolic and membrane-bound calmodulin in the striatum and hippocampus of the rat brain. Single doses of apomorphine and a low-dose amphetamine (1.25 mg/kg) resulted in a translocation of calmodulin, as measured by a decrease in membrane-bound and increase in cytosolic calmodulin in the striatum, whereas bromocryptine was ineffective. Amphetamine exerted a similar effect in the hippocampus and striatum. However, a high-dose amphetamine (5 mg/kg) had an opposite effect on translocation, in that there was an increase in membrane-bound calmodulin. Chronically applied amphetamine (5 mg/kg) and haloperidol (1 mg/kg), i.e. under conditions of dopamine receptor supersensitivity, tended to decrease cytosolic calmodulin in the striatum and hippocampus, and to increase membrane-bound calmodulin. The findings and, especially, the chronic effects of haloperidol and the high dose of amphetamine are interpreted in the light of the current concept which suggests that transmitters and intraneuronal signalling systems converge, thereby influencing the more complex processes of neuronal plasticity, rather than receptor sensitivity only.

[Application of implants for dental prostheses in indications for complete dentures. 2]

An interesting clinical case of fixed dental prostheses is described, performed via Bulgarian bioceramic intraosseous implants and two retained teeth on the upper jaw, i.e. indications for complete prostheses in a 38-years old female patient. The case has been solved in a way so that when necessary (retention of implants) guarantees a removable prosthesis with Bulgarian traverse-joint elements.

[Exchangeable system synthetics-rider at the bridge-joint prosthetics]

In order to improve the prosthetic supply, a clam-on system for bar-joint-mandibular dentures has been developed. When replacing clamp No. 1 by clamp No. 2 both the vertical translation and the frontal rotation of the prosthesis are ensured over a longer time of function. Placing at disposal ready-made plastic bar-joint elements facilitates the clinic and the laboratory technology for making the bar-joint-mandibular denture.

[In vitro cytotoxicity of melanoidins isolated from cooked meat and fish samples]

A study has been undertaken to investigate the biological activity of melanoidins isolated from meat samples baked according to Kuntscheva (electro-baking oven, 200-300 degrees C, 60-210 min) and from semi-finished meat products baked in swimming fat (200 degrees C, 3 X 50 min, repeated use of the oil) as well as from semi-finished fish products (190 degrees C, 60 min). A weak toxicity of the melanoidins formed within a longer thermal treatment, but no mutagenic effect was stated. The cytotoxic alterations showed no specific character.

[Articular-telescopic bridge prosthesis on loose teeth]

A clinical case is described for removable articulartelescopic bridge prosthesis of a defect, restricted distally by loose teeth (II degree of pathological looseness) and 3/4 atrophy of the alveolar bone. Compromised prosthesis has been realized by restriction and equalizing the mobility of the bridge-carriers by an articular and telescopic connection. Bulagarian articular elements have been used (TCE) for a soft contact and stabilization and sinking conical telescopes.

[Central incisors--implants]

Two clinical cases are presented in the paper with one of the most common defects of dentitions as an indication for implantation-prosthesis--the absence of the upper central incisors as a results from acute trauma. A good functional and aesthetic effect has been attained. The constructions are in good order and have no changes in the teeth and implants during the almost two-year period.

Changes in activities of fucokinase and fucosyltransferase in rat hippocampus after acquisition of a brightness discrimination reaction

Activities of enzymes involved in utilization of the glycoprotein precursor L-fucose (fucokinase and fucosyltransferase) were studied in rat hippocampal tissue after acquisition of a brightness discrimination reaction. Fucokinase activity was increased immediately after training, while fucosyltransferase revealed decreased values. However, 7 hr after training fucokinase activity showed normal values, while fucosyltransferase activity rose in trained animals over active and passive controls. The results are discussed in the light of a regulatory role that fucokinase and fucosyltransferase may play in fucose utilization under altered functional conditions.

Distribution of hippocampal glycoproteins as demonstrated in rats by lectin binding and autoradiography after intraventricular injections of labelled fucose, N-acetyl-glucosamine and mannose

The present study demonstrates distinct distribution patterns of glycoproteins in rat hippocampus, with respect to synthesis from precursors (autoradiography) and endogenous contents (lectin binding). The autoradiographic analysis performed 1, 2, 8 and 24 h after intraventricular injections of tritium-labelled L-fucose. N-acetyl-D-glucosamine and D-mannose revealed that up to 2 h after application of any of the three precursors, radioactivity occurred in the pyramidal and granular cell layers. Afterwards, however, rapid migration of label proceeded from the cell bodies into the neuropil after application of fucose and acetylglucosamine, while after injection of mannose a considerable amount of radioactivity stayed in the cell body layers, even 24 h after administration of labelled precursor. These findings were consistent with the histochemical visualization of glycoprotein constituents by fluorescent wheat germ lectin (preferentially binding to glucosaminyl residues) and concanavalin A-horseradish peroxidase (preferentially binding to mannosyl residues). These showed a heavy staining predominantly in neuropil and somata, respectively, with concanavalin A-binding giving more distinct patterns than the application of labelled mannose. The usefulness of the three glycoprotein precursors as correlates with functional behavioural changes in discussed.

Mechanisms of dopamine induced changes in hippocampal glycoprotein metabolism

In rat hippocampal slices incubated in the presence of dopamine, a relatively strong correlation was observed between changes in the incorporation of 3H-fucose into total proteins and the formation of GDP-3H-fucose. However, in hippocampal homogenate the incorporation of 14C-fucose from GDP-14C-fucose was not stimulated by dopamine. In contrast, the incorporation of 3H-fucose was stimulated by dopamine to a similar extent observed in hippocampal slices. Furthermore, in hippocampal slices dopamine did not increase the activity of fucosyltransferase. These results, together with our previous findings, suggest that the increased incorporation of fucose induced by dopamine in the hippocampal slices may be due to a receptor-mediated cAMP-dependent regulation, which controls the rate of fucosylation of acceptor-glycoproteins either at the level of fucose phosphorylation or of formation of GDP-fucose rather than the activity of fucosyltransferase.

Effect of L-fucose on brain protein metabolism and retention of a learned behavior in rats

The intraperitoneal or intraventricular application of L-fucose (100 mg/kg or 75 microgram, respectively) prior to training in shuttle box avoidance as well as in shock-motivated brightness discrimination in rats significantly improved the retention of learned behavior 24 hr later. The application of D-fucose was without influence on retention. In naive animals, intraventricularly applied L-fucose (75-200 microgram) caused an increase in the rate of protein synthesis in the hippocampus, resulting in a significant increase in total proteins of this brain structure, mainly attributed to the Tris-insoluble protein fractions. The results are discussed in terms of an activation of glycoprotein formation by increasing supply with L-fucose.

Electrophoresis of water-insoluble leptospiral proteins and the taxonomy of Leptospira

The cellular debris obtained after lysis of Leptospira were solubilized by sodium dodecyl sulfate and studied by polyacrylamide electrophoresis, comparing the molecular weight and relative concentration of the protein bands. The percentage similarity of 30 characteristic bands from 21 Leptospira strains, belonging to the main pathogenic and some saprophytic serogroups, was calculated; A partial matching of the derived dendrogram with the other classifications was observed.