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At least 451 records · Page 25Linked to original sources
PubMed2003

Trimethoprim induces heat shock proteins and protein aggregation in E. coli cells.

Trimethoprim (TMP), an inhibitor of dihydrofolate reductase, decreases the level of tetrahydrofolate supplying one-carbon units for biosynthesis of nucleotides, proteins, and panthotenate. We have demonstrated for the first time that one of the effects of the TMP action in E. coli cells is protein aggregation and induction of heat shock proteins (Hsps). TMP caused induction of DnaK, DnaJ, GroEL, ClpB, and IbpA/B Hsps. Among these Hsps, IbpA/B were most efficiently induced by TMP and coaggregated with the insoluble proteins. Upon folate stress, deletion of the delta ibpA/B operon resulted in increased protein aggregation but did not influence cell viability.

Escherichia coli↗
PubMed2005

Characterization of phages virulent for Sarothamnus scoparius bradyrhizobia.

Four virulent phages--PhiDl, PhiTl, PhiCYT21, and PhiOS6, infective on Sarothamnus scoparius rhizobia--were isolated from the soil and characterized for morphology, host range, rate of adsorption to bacterial cells, and genome size. New phages were separated into two morphological families: Siphoviridae with long, noncontractile tails (PhiDl, PhiTl) and Myoviridae with long, contractile tails (PhiCYT21, PhiOS6). They were also classified into two groups by a host specificity. One of them included viruses (PhiDl and PhiTl) that lysed S. scoparius bradyrhizobia and Bradyrhizobium sp. (Lupinus) strain Dl, and the second one comprised phages (PhiCYT21 and PhiOS6) that parasitized only Scotch broom native microsymbionts. Phages specific for S. scoparius rhizobia were differentiated not only by morphology and host range but also by a genome size that was in the range from 47,583 to 60,098 b.p.

Bradyrhizobiaceae↗
PubMed2004

Intragenic suppressors that restore the activity of the maturase encoded by the second intron of the Saccharomyces cerevisiae cyt b gene.

The protein encoded by the second intron (bi2) of the mitochondrial cyt b gene from Saccharomyces cerevisiae functions as a maturase promoting intron splicing. This protein belongs to a large family characterized by the presence of two conserved motifs: LAGLIDADG (or P1 and P2). We have isolated and characterized spontaneous revertants from two mis-sense mutations, G85D and H92P (localized in the P1 motif of the bi2-maturase), that have a detrimental effect on intron splicing. All analyzed revertants are intragenic and resulted from monosubstitutions in the mutated codons. Only true back-mutations that restor the initial glycine 85 and a pseudoreversion that replaces the deleterious aspartic acid 85 by alanine were found in revertants of the mutant G85D. In contrast, all possible monosubstitutions in the mutated codon H92P were identified among the revertants of this mutant. The maturase activity of all novel forms of the protein is similar to the wild-type protein.

Base Sequence↗
PubMed2006

Visualisation of microtubules and actin filaments in fixed BY-2 suspension cells using an optimised whole mount immunolabelling protocol.

Excellent visualisation of microtubules and actin filaments was obtained in fixed tobacco BY-2 suspension cells after optimising a protocol for whole mount immunolabelling. The procedure is based on modification of fixation, cell wall digestion, dimethyl sulfoxide (DMSO) treatment, post fixation, and blocking. The most critical aspects of successful preservation and visualization of cytoskeletal elements appeared to be: a two-step fixation with paraformaldehyde and glutaraldehyde before enzymatic cell wall digestion and a post fixation with aldehydes thereafter. The method allows the improved visualization of the organisation of the microtubular and actin filament arrays during the successive stages of cell division and at interphase. Although we present the application of our protocols for cytoskeleton labelling, the excellent results show the potential of using this method for the analysis of various proteins and molecules in plant cells.

Actin Cytoskeleton↗
PubMed2005

Day-night specific binding of 2-[125I]iodomelatonin and melatonin content in gill, small intestine and kidney of three fish species.

Some of melatonin's (Mel) well-established physiological effects are mediated via high-affinity cell-membrane receptors belonging to the superfamily of G-protein-coupled receptors. Specific binding of ligand 2-[(125)I]iodomelatonin, using membrane preparations from osmoregulatory tissues of flounder, rainbow trout and sea bream, together with Mel concentrations in the tissues and plasma were studied. The kidney, gill and small intestine samples were collected during the day and at night. The dissociation constants (K (d)) and maximal binding densities (B (max)) were calculated for each tissue at 11:00 and 23:00 h. The binding sites with K (d) values in the tissues in the picomolar range indicated the high affinity. K (d) and B (max) values were tissue- and species-dependent. The GTP analogue [Guanosine 5'-O-(3-thiotriphosphate)] treatment significantly reduced the B (max) value, indicating that the 2-[(125)I]iodomelatonin-binding sites are probably coupled to a G-protein. No daily variations in K (d) and B (max) values were observed. These are the first studies of the presence of 2-[(125)I]iodomelatonin-binding sites in the small intestine, kidney tubule and gill of fish. The data strongly suggest new potential targets for Mel action and the influence of Mel on water/ion balance in fish. The intestine seems to be a site of Mel synthesis and/or an active accumulation of the hormone.

Animals↗
PubMed2003

Pineal cysts in childhood.

INTRODUCTION: Little is known about the incidence and symptomatology of pineal cysts in children. Until now, the proper management of this group of patients has not been established. PURPOSE: The purpose of this study was to evaluate the epidemiological and clinical features of pineal cysts in children and adolescents and to try to find guidelines for their management. METHODS AND RESULTS: We analyzed 24 patients (17 girls, mean age 9, and 7 boys, mean age 14) with pineal cysts found as the only pathology on MRI. Six patients were treated surgically (excision of the cysts via a supracerebellar-infratentorial approach) because of the progression of neurological symptoms or the enlargement of the cyst at follow-up. In this group of patients, no surgery-related complications were noted, nor was residual cyst observed on postoperative MRI. In 4 cases, histological examination revealed simple cysts, but in 2 cases pineocytomas were diagnosed. Preoperative symptoms disappeared except light headache in 2 cases and in 1 case no improvement was obtained. The remaining 18 patients had a mean follow-up of 38 months (range 24-60 months). None of the cysts diminished or collapsed. We also measured the circadian pattern of melatonin secretion as well as beta-HCG and AFP levels in serum before surgery. We found very high night levels of melatonin in both of the patients with pineocytomas, while the patients with pineal cysts showed normal or depressed melatonin secretion profile. CONCLUSION: We concluded that though most pineal cysts were clinically benign they should be followed up for many years. If the cyst grows larger in follow-up MRI study and neurological symptoms are progressive, surgical treatment should be performed. In the authors' opinion, one of the markers discriminating benign and neoplastic lesions may be melatonin.

Adolescent↗
PubMed2005

Difficulties in differentiation of Parry-Romberg syndrome, unilateral facial sclerodermia, and Rasmussen syndrome.

INTRODUCTION: Parry-Romberg syndrome (progressive facial hemiatrophy) is a unilateral, slowly progressive atrophy affecting the skin, subcutaneous tissues, muscles, and bones. The relationship between Parry-Romberg syndrome and connective tissue disorders, especially scleroderma en coup de sabre, is still unclear. The neurological symptoms, including epilepsy, migraine, and brain lesion, on neuroimaging may be similar. Rasmussen encephalitis (RE) is connected with chronic inflammation and damage of one hemisphere. Clinically, it is manifested by epileptic partial seizures and unilateral neurological symptoms. CASE REPORT: The authors present the case of a 10-year-old girl with features suggestive of RE, with refractory partial motor dextrolateral seizures followed by development of hemiparesis and with progressive intellectual deterioration. At the age of 2 years, some changes on the left part of the face typical of Parry-Romberg syndrome or a linear form of scleroderma were noticed. DISCUSSION: The authors discussed the difficulties in differential diagnosis in that patient. The presented girl constitute the case from the borderline zone of the aforementioned disorders.

Cerebral Cortex↗
PubMed2004

Dietary trans fatty acids and composition of human atheromatous plaques.

Dietary fatty acids are incorporated into atheromatous plaques mainly in the form of cholesterol esters. Physicochemical properties of the plaque (e. g. mechanical strength) depend on its fatty acid composition. Trans isomers of unsaturated fatty acids (TFA) are known to reduce the availability of fatty acid precursors for the synthesis of anticoagulant PG(1) and PG(3) prostaglandins. The present study was undertaken to determine the content of trans isomers in atheromatous plaques and to search for correlations between trans isomers in the plaque and adipose tissue. Atheromatous plaques were obtained from 31 patients who underwent surgery due to atherosclerotic stenosis of the abdominal aorta, iliac or femoral arteries. Fatty acids were extracted and separated as methyl esters using gas chromatography (GC) with an internal standard. Correlations were searched for with statistical methods, taking the level of significance as p < 0.05. We found spatial and positional isomers of sixteen- and eighteen-carbon fatty acids in plaques and adipose tissue, with elaidic acid (C18:1 trans-9) being the most abundant. Every plaque and adipose tissue sample contained linolelaidic acid (C18:2 trans-9 trans-12) which is derived exclusively from linoleic acid, as well as conjugated dienes of linoleic acid (CLA) produced during oxidative processes. The presence of trans isomers of fatty acids in the atheromatous plaque seems to be of relevance to plaque formation. Of much concern is the detection of elaidic and linolelaidic acids which adversely affect the physiologically important metabolism of eicosanoids. The TFA pool in adipose tissue has little effect on the amount of these acids in the atheromatous plaque. Apparently, the presence of TFA in atheromatous plaques is the result of processes taking place during plaque formation and maturation.

Adipose Tissue↗
PubMed2006

Inhibition of phospholipase A(2) activity by conjugated linoleic acids in human macrophages.

The objective of this study was to assess the effect of conjugated linoleic acid isomers (CLAs) on the expression and activity of phospholipases A(2) (PLA(2)) in human macrophages. Macrophages were incubated with 30 microM cis-9, trans-11 and trans-10, cis-12 CLAs for 48 h. After incubation, the total activity of phospholipases as well as the expression of mRNA for cytosolic (cPLA(2)) and secretory (sPLA(2)) phospholipases and activity of sPLA(2) were measured. Both CLA isomers reduced the total activity of PLA(2) (by 30.2%, P < 0.01 for cis-9, trans-11 CLA and by 30%, P < 0.001 for trans-10, cis-12 CLA). Trans-10, cis-12 CLA isomer downregulated the expression of mRNA of sPLA(2) and decreased the enzymatic activity of this enzyme (by 23%, P = 0.02) in macrophages. Conjugated linoleic acid isomers can significantly reduce the activity of PLA(2) in macrophages and downregulate sPLA(2) expression. The consequence of this effect may be reduction of releasing the arachidonic acid (AA) from the cellular membranes of macrophages.

Down-Regulation↗
PubMed2003

Tumour necrosis factor-alpha and the failing heart--pathophysiology and therapeutic implications.

Immune activation plays a significant role in the development and progression of chronic heart failure (CHF). Indeed, pro-inflammatory cytokines, especially tumour necrosis factor-alpha (TNFalpha) are activated in this condition and exert direct detrimental actions on the myocardium. Physiological dampeners of TNFalpha production, such as interleukin-10, catecholamines, cortisol, and others fail in the course of the disease. However, the outcomes of two large-scale clinical trials with etanercept and infliximab, which directly antagonise TNFalpha have been rather disappointing. Nevertheless, TNFalpha antagonism remains a major target of CHF therapy, although counterbalancing this cytokine alone may not be sufficient.

Heart Failure↗
PubMed2004

Plastic solutions for orthopaedic problems.

INTRODUCTION: Infection and exposure of the implant may occur in 1-12% of patients operated on for arthroplasty or osteosynthesis. Variables such as tissue viability, presence of infection, exposure of osteosynthesis material and patient-related factors contribute to the lack of general consensus regarding the management of these defects. MATERIALS AND METHODS: Between January 1999 and January 2001, six patients were treated for complex soft-tissue defects following various orthopaedic procedures at the Department of Plastic Surgery in the Slotervaartziekenhuis in Amsterdam, a rheuma-orthopaedic orientated hospital. All patients were initially treated by radical debridement and vacuum-assisted closure (VAC) system of the wound. After 1 week, this was followed by transplantation of a pedicled or free flap to cover the defect. We studied the medical history, initial orthopaedic procedure, wound treatment, transplanted flap and outcome of plastic surgery in this group. RESULTS: Plastic surgical intervention led to wound closure in all cases. In only one case was the osteosynthesis material removed because of osteomyelitis. CONCLUSIONS: We conclude that the earlier coverage with vital tissue is obtained, the lower the incidence of infection. Early consultation by a plastic surgeon will increase a positive outcome of treatment of complex tissue defects.

Adult↗
PubMed2003

Expression and localization of tight junction-associated proteins in human hair follicles.

Tight junctions (TJ) are barrier-forming intercellular junctions selectively sealing cells and controlling the paracellular pathway. They have been well-characterized in simple epithelia and endothelia but have only recently been described in stratified epithelia such as epidermis, oesophagus and oral mucosa. Various epithelial layers which are partly in morphogenic continuity with the epidermis and develop therefrom during early fetal life, build the human hair follicle. The barrier function of these epithelial layers seems to be important for the universal continuity of the barrier represented by the skin. We show the presence of the TJ proteins ZO-1, occludin, and various claudins in the hair follicle and demonstrate their impressive heterogeneous distribution pattern within a given stratum as well as within its different epithelial layers. Coexpression of the various TJ proteins, arguing for typical TJ structures, can be observed especially in cell layers facing the hair shaft and the stratum corneum, and in addition at the border between the outer and inner root sheaths. Usually they are found in close proximity to desmosomal and adherens junction proteins. The morphological and biological importance of these findings and the possible roles of TJ in hair follicles, e.g. in follicular penetration, are discussed.

Adherens Junctions↗
PubMed2007

Formation of spheroids composed of Henle layer cells and fat droplet in the cultures of rat hair follicles.

The aim of the study was to elucidate the structure of dark-looking spheroids, which appeared in the cultures of hair follicles isolated from rat dermis. These spheroids were particularly numerous when if a keratinocyte growth medium with a reduced amount of supplements was used. Light microscopic observations disclosed that these spheroids consisted of fat droplets covered by cells reacting with the antitrichohyalin AE 15 monoclonal antibody. These fat droplets originated from subcutaneous adipocytes damaged during isolation and remained in cultures. The morphological appearance of cells covering fat droplets studied at the EM level corresponded with that of the cells in the Henle layer of the intact hair follicles in the dermis. EM observations further suggested that in cultures the Henle layer detached from the Huxley layer and that the fat droplets penetrated under the Henle layer resulting in formation of a spheroid. Since from 2 cm2 of rat skin more than 400 spheroids were regularly obtained, it seems conceivable that they could be exploited for isolation of the Henle layer cells.

Animals↗
PubMed2007

Markers of antioxidant defence system and lipid peroxidation in peripheral blood of female patients with chronic idiopathic urticaria.

Oxidative stress is an important event in lesional skin of patients with chronic idiopathic urticaria (CIU). In the present study, we assessed blood oxidant/antioxidant status of patients suffering from CIU with positive response to autologous serum skin test (ASST) and with negative ASST, to improve our understanding of biological processes and the part of oxidative stress in this disease. Activities of manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (Cu/ZnSOD), glutathione peroxidase (GSH-PX), and catalase (CAT) as indices of enzymatic antioxidant capacity, as well as malondialdehyde (MDA) level as a maker of lipid peroxidation were measured in plasma and erythrocytes from 14 CIU female patients showing positive ASST, 31 CIU female patients with negative ASST and in 19 sex- and age-matched healthy subjects. The antioxidant enzyme activity in plasma and in erythrocytes did not differ significantly among the three groups. Also, the plasma and erythrocytes MDA levels were similar in the three groups. Based on our results, it seems that systemic activity of the enzymatic antioxidants (CuZn/SOD, MnSOD, GSH-Px, and CAT) as well as level of lipid peroxidation determined by MDA may not be increased in the course of immune-inflammatory processes associated with CIU. We also suggest that the systemic oxidant/antioxidant status of CIU patients, showing positive response to ASST, may not be different from that of CIU patients with negative ASST.

Adult↗
PubMed2003

Etiopathogenesis of cholesteatoma.

Cholesteatoma is a destructive lesion of the temporal bone that gradually expands and causes complications by erosion of the adjacent bony structures. Bone resorption can result in destruction of the ossicular chain and otic capsule with consecutive hearing loss, vestibular dysfunction, facial paralysis and intracranial complications. Surgery is the only treatment of choice. The etiopathogenesis of cholesteatoma, however, is still controversial. This review was designed to understand the reasons for these disparities and to reduce or eliminate them. Future studies focused on developmental, epidemiological, hormonal and genetic factors as well as on treatment are likely to contribute to further understanding of cholesteatoma pathogenesis.

Antigens, Differentiation↗
PubMed2005

Cytokeratin expression pattern in congenital and acquired pediatric cholesteatoma.

Pediatric cholesteatoma can be classified as congenital or acquired based on clinical criteria. We studied the expression patterns of five distinctive cytokeratins in both types of cholesteatoma in order to improve understanding of their pathogenesis and origin. A comparable expression pattern for CK10, CK14, CK18, CK19 and 34betaE12 antigens was found in the matrix of congenital and acquired pediatric cholesteatoma. Our results demonstrate that congenital and acquired pediatric cholesteatoma exhibit an identical cytokeratin distribution pattern, suggesting that they share a common origin. Therefore, it seems possible that a portion of the so-called "acquired" cholesteatoma may actually originate from advanced congenital cholesteatoma with secondary destruction of the tympanic membrane in the pediatric patient population.

Child↗
PubMed2005

Apoptosis in the pathogenesis of cholesteatoma in adults.

The aim of this study was to determine the distribution and apoptotic capacity in the various layers of cholesteatoma epithelium compared to the normal skin. Cholesteatomas were collected during surgical procedures of the ear. Normal skin specimens taken from the retroauricular area served as controls. Apoptosis was detected by using highly specific antibodies against APO2.7 antigen. The Membstain Apoptosis kit Direct based on in situ labeling of nuclear DNA fragmentation (Tolt-mediated dUTP nick and labeling TUNEL staining) was used. The distribution of apoptotic cells in the layer of the cholesteatoma epithelium and the epidermis was determined. The percentage of apoptotic cells was then counted per 100 cells of cholesteatoma epithelium and the normal epidermis in three different areas of each section and expressed in terms of mean +/- SD. An automatic analyzing system was used for counting. In normal epidermis, the apoptotic cells were observed in the granular layer of the epidermis. The percentage of these cells was 28.5 +/- 8.1%. A significantly greater number of apoptotic cells was observed in the suprabasal layers of the cholesteatoma epithelium (47.39 +/- 6.2%). A statistically significant difference was obtained for APO2.7-positive cells in the cholesteatoma epithelium as compared to the skin (P < 0.05) as determined by Student's t-test and the Mann-Whitney U test. Apoptotic activity is mainly observed in the suprabasal layer of cholesteatoma epithelium. It is not seen in the basal layer. Apoptosis plays an important role in the pathogenesis of cholesteatoma. It seems to be part of the differentiation and accumulation of keratin debris within the middle ear and expansion of cholesteatoma.

Adult↗