[Early melanoma detection. Skin cancer screening must become an insurance covered procedure].
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Germany↗
Biomedical subjects
M Steinert
Publications and source records attributed to M Steinert.
Identification and in situ detection of intracellular bacteria in the environment.
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Bacteria↗
Expression and use of the green fluorescent protein as a reporter system in Legionella pneumophila.
The gene encoding the green fluorescent protein (GFP) was used as a reporter gene in Legionella pneumophila. To analyze GFP expression in Legionella, transcriptional fusions of gfp with the Legionella-specific mip (Macrophage Infectivity Potentiator) promoter (P(mip)) and the sod (SuperOxide Dismutase) promoter (P(sod)) derived from Listeria monocytogenes were constructed. Following transformation into the virulent L. pneumophila strain JR 32, strong GFP-mediated fluorescence was detected with both plasmids, although the sod promoter was associated with a 1ten-fold higher intensity. No fluorescence was observed in L. pneumophila transformed with the promoterless gfp gene. Comparison of fluorescence yields between various L. pneumophila strains that differ in their virulence characteristics and were transformed with the P(mip)-gfp carrying plasmid revealed no differences in GFP expression. Infection studies using Acanthamoeba castellanii as host and recombinant L. pneumophila strains carrying the P(mip)-gfp and P(sod)-gfp fusions indicated that the mip promoter was expressed when the bacteria replicated intracellularly. GFP expression was also used to monitor, in infected A. castellanii cells, the intracellular survival of, and incidence of host-cell killing by. L. pneumophila strains that vary in their virulence properties. As quantified by flow cytometry the highly virulent L. pneumophila strain Corby was twice as infectious to A. castellanii as the Philadelphia strain JR 32. Using the avirulent Philadelphia derivative 25D invasion but no intracellular multiplication was observed. In addition, we examined by flow cytometry the influence of cytochalasin D, cycloheximide, and methylamine on the uptake of Legionella by A. castellanii. In conclusion, gfp appears to be a convenient reporter gene whose expression in Legionella can be followed in real time and allows analysis of promoter activities in Legionella and monitoring of the infection process.
Acanthamoeba↗
[Recurrent laryngeal nerve paralysis as intubation injury?].
INTRODUCTION: Vocal cord paralysis is a important complication in thyroid gland surgery. A prospective study was conducted ascertain the frequency of laryngeal nerve palsy not caused by surgical trauma. PATIENTS AND METHODS: Two hundred and ten patients were investigated laryngoscopically pre- and postoperatively after short-term intubation in the course of operations far removed from thorax or neck region. We noted the inner diameter of the tube, intubation problems, the qualification of the anaesthesiologist and the positioning of the patient. RESULTS: Preoperatively we found previously unknown unilateral laryngeal nerve palsy in 1.9% of cases. Postoperatively there were pathological findings of vocal cords in 13 patients (6.2%). In 10 patients a direct lesion (oedema, rubor, haematoma, granuloma) was established. Three patients (1.4%) were found to have a movement disorder caused by a neural lesion without morphological findings, leading to restitutio ad integrum in two of three cases after 6 months. CONCLUSION: The frequency of intubation-related recurrent nerve palsy is 1.4% transiently and 0.5% permanently. The reasons are discussed. Preoperative laryngoscopic investigation of vocal cords should be carried out before intubation.
Adolescent↗
Symbiosis and pathogenesis: evolution of the microbe-host interaction.
Symbiotic and pathogenic bacteria have in common that they live in or on host organisms or host cells. To make a successful living in eukaryotic hosts, bacteria must possess the traits to recognize a given host and establish adherence. When the bacterial location is internal or intracellular, they must further have the ability to invade, to establish a niche, and finally to multiply within a host. The underlying mechanisms which allow this form of existence show similarities between symbiotic and pathogenic bacteria. The final outcome, however, may result in a wide spectrum of consequences for the host ranging from the acquisition of novel metabolic pathways to damage or death. Despite the vastly different forms of interactions, symbiotic and pathogenic bacteria have in common that they are adapted to a particular environmental niche represented by the host organism or compartment thereof. This contribution reviews the evolutionary forces which have shaped the microbial-host interactions. Particular emphasis is placed on the genetic and molecular mechanisms that drive bacterial evolution in response to the selective pressures of the host environment.
Animals↗
Cloning and characterization of a Legionella pneumophila-specific gene encoding a member of the LysR family of transcriptional regulators.
Flagellin gene regulation in Legionella pneumophila is modulated by various environmental factors. The expression of the virulent phenotype seems to be linked genetically to flagellum expression. To better understand the mechanisms of flagellin gene expression in L. pneumophila (Lp), we screened a pool of plasmids from a L. pneumophila Corby genomic library for the ability to prevent or reduce luciferase activity in the Escherichia coli strain YK410, which harbours a Lp-pflaA-luxAB fusion. We cloned a DNA fragment encoding the N-terminal part of a protein with significant similarity to members of the LysR family of transcriptional regulators (LTTRs). The entire gene, cloned by inverse PCR, was named flaR. It encodes a protein of 302 amino acids, and computer-assisted analysis of the amino acid sequence revealed a helix-turn-helix motif located near the N-terminus of the protein. The FlaR protein exhibits 21-31% identity to various LTTRs. Furthermore, gel retardation experiments indicate that the FlaR protein is able to bind to its own promoter region and, to a lesser extent, to the flaA promoter of L. pneumophila. The flaR promoter region contains putative LysR binding motifs and two putative Fur boxes. Taken together, these results indicate that FlaR is a DNA-binding protein which belongs to the LTTR family. Southern analysis with a L. pneumophila Corby-specific flaR probe revealed homologous genes in various L. pneumophila strains, but not in the 12 nonpneumophila strains tested so far.
Amino Acid Sequence↗
Evaluation of ultracision in lung metastatic surgery.
BACKGROUND: There are very few studies on the histological outcome of lung metastatic surgery using the Ultracision particularly in deeper areas of the lung. METHODS: In a prospective study, we resected 24 lung metastases from 18 patients using the Ultrasonic scalpel (Ethicon Endo-Surgery, Norderstedt, Germany). We analyzed the risk of bleeding and air leakage as well as the histopathological features of the resection area. RESULTS: There was no intraoperative bleeding and, in 72%, no intraoperative air leakage. The resection surface was closed with a suture. In 8 cases, the metastases were located deeply, near the hilus of the lobe which did not necessitate a lobectomy. Histologically, occluded blood vessels as well as occluded small bronchioli under 0.1 cm were observed. There was no evidence of deep tissue destruction. No postoperative complications occurred. CONCLUSIONS: Ultracision in metastatic lung surgery is an appropriate method of treatment with minimum risk of bleeding or air leakage. This procedural approach allows for adequate resection of lung metastases while sparing a generous amount of healthy lung tissue.
Adult↗
Common molecular mechanisms of symbiosis and pathogenesis.
Traditionally, symbiotic and pathogenic interactions were considered different manifestations of the bacteria-host interaction. However, the molecular mechanisms that mediate communication between and cellular modulation of the involved partners are quite similar. With this review we aim to contribute to a reduction of the traditional gap between symbiosis and pathogenesis research.
Animals↗
Exercise-induced anaphylaxis to wheat flour.
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Adult↗
Dictyostelium discoideum: a new host model system for intracellular pathogens of the genus Legionella.
The soil amoeba Dictyostelium discoideum is a haploid eukaryote that, upon starvation, aggregates and enters a developmental cycle to produce fruiting bodies. In this study, we infected single-cell stages of D. discoideum with different Legionella species. Intracellular growth of Legionella in this new host system was compared with their growth in the natural host Acanthamoeba castellanii. Transmission electron microscopy of infected D. discoideum cells revealed that legionellae reside within the phagosome. Using confocal microscopy, it was observed that replicating, intracellular, green fluorescent protein (GFP)-tagged legionellae rarely co-localized with fluorescent antibodies directed against the lysosomal protein DdLIMP of D. discoideum. This indicates that the bacteria inhibit the fusion of phagosomes and lysosomes in this particular host system. In addition, Legionella infection of D. discoideum inhibited the differentiation of the host into the multicellular fruiting stage. Co-culture studies with profilin-minus D. discoideum mutants and Legionella resulted in higher rates of infection when compared with infections of wild-type amoebae. Because the amoebae are amenable to genetic manipulation as a result of their haploid genome and because a number of cellular markers are available, we show for the first time that D. discoideum is a valuable model system for studying intracellular pathogenesis of microbial pathogens.
Acanthamoeba↗
Recurrent pleural effusion and a mediastinal mass.
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Humans↗
Expression and regulation of regulated on activation, normal T cells expressed and secreted in thyroid tissue of patients with Graves' disease and thyroid autonomy and in thyroid-derived cell populations.
Thyroid glands affected by Graves' disease (GD) show striking lymphocytic infiltration, mainly by CD45RO(+) T cells. The mechanisms by which the various lymphocytic subsets are recruited and maintained in the thyroid are unknown. RANTES (regulated on activation, normal T cells expressed and secreted) in interaction with its receptors (CCR1, CCR3, CCR4 and CCR5) may be one of the favorite chemokines involved in the cell trafficking and maintenance. RANTES messenger RNA (mRNA) was quantified in the thyroid tissue of 16 patients with GD and 7 patients with thyroid autonomy (TA), using competitive RT-PCR. We found a clear correlation between the RANTES mRNA level and 1) the degree of T-cell infiltration (r = 0.68), and 2) the level of serum antibodies to thyroid peroxidase (r = 0.76) in GD but not in TA patients. There was no difference between the autonomous nodules and the quiescent surrounding tissue in TA patients. To define the cellular source of RANTES mRNA and protein, we examined various thyroid-derived cells. Lymphocytes showed a markedly higher basal RANTES mRNA and protein level (mean +/- SEM; pg/mL, n = 3; 140 +/- 30) than thyrocytes (12 +/- 5) and fibroblasts (9 +/- 2). Lymphocyte stimulation with PMA enhanced RANTES secretion significantly (4490 +/- 200). Fibroblasts responded to stimulation with interleukin 1 (530 +/- 220) and tumor necrosis factor alpha (2780 +/- 1790), whereas thyrocytes did not. However, some thyroid carcinoma cell lines showed very high basal and stimulated RANTES expression. Lymphocytes expressed the mRNA of all chemokine receptors that bind RANTES. The number of CCR3(+) and CCR5(+) T cells was significantly higher in thyroid-derived leukocytes than in those in the peripheral blood stream. We conclude that RANTES expression, mainly by lymphocytes, is perhaps involved in the maintenance of lymphocytic infiltration and, therefore, in the autoimmune responses in GD.
Cells, Cultured↗
[Therapeutic management of postoperatively diagnosed bilateral recurrent laryngeal nerve paralysis].
UNLABELLED: Bilateral vocal cord paralysis is a rare but potentially dangerous postoperative complication in thyroid gland surgery. There is a controversial discussion about therapeutic management of postoperative bilateral vocal cord paralysis. METHODS: We analysed the frequency of bilateral nerve palsy in 985 operations. The disease of thyroid gland, the operative procedure, the exposure of laryngeal nerve, the mobility of vocal cord detected by an otolaryngologist, clinical symptoms and therapy of patients with bilateral paralysis were analysed. All patients were examined immediately postoperatively and 5 days, 14 days, 6 and 12 months after resection. RESULTS: The overall transient bilateral palsy rate was 0.7%, the permanent 0.3%. The palsy rate depended on the disease of thyroid gland. After resection of simple goitre we found a 0.2% transient injury rate (0.1% permanent), after operation of thyroid cancer 2.0% transient (1.0% permanent) and in cases of recurrent goitre 5.9% transient (1.9% permanent) palsies. The immediate postoperative symptoms are also very different. There are patients suffering from stridor and dyspnoea, patients with dysphonia without dyspnoea and those without any symptoms. These different clinical symptoms are due to the different grade of laryngeal nerve damage and the resulting position of vocal cords. The bilateral paralysis was completely temporary in 4 cases. 12 months later 4 patients suffered from dysphonia. Only in 3 patients with thyroid cancer and a preoperative unilateral vocal cord paralysis tracheostomy was necessary after operation. The vocal cord mobility did not recover in these 3 cases after 12 months and the patients are not decannulated. DISCUSSION: Bilateral paralysis is only relevant in thyroid cancer and recurrent goitre. The symptoms varies and no patient should leave the hospital without examination of the vocal cords by an otolaryngologist. Because vocal cord paralysis is temporary in most cases an emergency tracheostomy is seldom indicated.
Adult↗
Regrowth of Legionella pneumophila in a heat-disinfected plumbing system.
We examined the factors involved in the occurrence of Legionellaceae in a hospital water system and the recontamination by Legionella pneumophila after a thermal disinfection procedure was studied. Three months after the heat treatment (70 degrees C), the regrowth of the two prevalent Legionella strains (L. pneumophila serogroup 1 [Oxford-like] and L. pneumophila serogroup 2) reached the original level of cell numbers. Genomic analysis (pulsed-field gel electrophoresis) revealed the strains to be survivors of the decontamination. Temperature tolerance experiments showed that the serogroup 1 strain exhibited a higher tolerance to 60 degrees C than the serogroup 2 strain, which could account for the order of reappearance of the strains after the heat treatment. Potential host amoebae, including Acanthamoeba spp. and Vahlkampfia spp., which are known to play a critical role in the amplification process of Legionella, were isolated from the plumbing system. In-vitro studies demonstrated both Legionella strains for a similar rate of multiplication in A. castellanii. In competitive coinfections, however, the serogroup 1 strain achieved a higher rate of multiplication if compared with the serogroup 2 strain.
Acanthamoeba↗
Mycobacterium avium bacilli grow saprozoically in coculture with Acanthamoeba polyphaga and survive within cyst walls.
Protozoans are gaining recognition as environmental hosts for a variety of waterborne pathogens. We compared the growth of Mycobacterium avium, a human pathogen associated with domestic water supplies, in coculture with the free-living amoeba Acanthamoeba polyphaga with the growth of M. avium when it was separated from amoebae by a 0.1-micron-pore-size polycarbonate membrane (in a parachamber). Although viable mycobacteria were observed within amoebal vacuoles, there was no significant difference between bacterial growth in coculture and bacterial growth in the parachamber. This suggests that M. avium is able to grow saprozoically on products secreted by the amoebae. In contrast, Legionella pneumophila, a well-studied intracellular parasite of amoebae, multiplied only in coculture. A comparison of amoebae infected with L. pneumophila and amoebae infected with M. avium by electron microscopy demonstrated that there were striking differences in the locations of the bacteria within amoebal cysts. While L. pneumophila resided within the cysts, M. avium was found within the outer walls of the double-walled cysts of A. polyphaga. These locations may provide a reservoir for the bacteria when environmental conditions become unfavorable.
Acanthamoeba↗
[Incidence of damage to the recurrent laryngeal nerve in surgical therapy of various thyroid gland diseases--a retrospective study].
UNLABELLED: We investigated the incidence of the recurrent laryngeal nerve (RLN) palsy after thyroid gland surgery in 725 cases. The incidence was correlated to the different diseases of the thyroid gland, to the operative procedure (subtotal resection, lobectomy, thyroidectomy), to the intraoperative exploration of the nerve and to the surgeons' state of training. RLN palsy was found in 7.6 per cent (4.8 per cent nerve at risk) five days after surgery. A permanent RLN damage was defined as a persisting paralysis of the vocal cord six months after surgery. Permanent nerve damage occurred in 2.1 per cent for euthyroid nodular goitre, for recurrent goitre in 11.7 per cent and for thyroid carcinoma in 10.1 per cent. There was a statistically significant difference between the number of RLN pareses occurring after nerve exposure with 4.2 per cent and that occurring after non-exposure with 1.1 per cent for subtotal lobectomy. 67.7 per cent of these pareses at day five were transient. The RLN palsy rate for Senior House Officers was 6.7 per cent but there where none for registrars and consultants. CONCLUSIONS: The RLN damage five days after thyroid gland surgery is mainly caused by the great number of recurrent goitre and thyroid cancer (16.1 per cent), the rate of procedures performed by younger surgeons and the near total resection of euthyroid goitre. The exposure of RLN is important for the training to manage thyroid gland surgery.
Cross-Sectional Studies↗
[Indications and surgical therapy of thyroid gland diseases--analysis of 725 operated patients].
Diseases of the thyroid gland are an important part of elective surgical procedures. The adequate surgical therapy is at present standardized and requires a permanent qualitative control to reduce avoidable complications. The relation between men and women in our patients (n = 725) was 1 to 5. The mean age was 51.2 years. 10% (n = 79) of the patients were hyperthyroid. 646 patients had benign disease; and 79 patients were found to have malignancy of the thyroid gland. The most common indication for an operation was bilateral multinodular goitre (n = 325) in combination with a cold nodule (n = 123), in 79 patients latent hyperthyroidism or Morbus Basedow (n = 22). Struma nodosa with retrosternal extension (n = 49), recurrence of goitre (n = 34), thyroiditis (n = 12) and dystopic goitre (n = 2) were rare in these patients. Patients with malignancy of the thyroid gland were always treated by thyroidectomy or completed thyroidectomy with lymphnode dissection. In the cases of benign disease the surgical methods were variable, although the bilateral subtotal resection (n = 413) predominated. While doing so the radical resection of parenchyma with a persistent functioning remnant of goitre of 5 cm3 was favoured. The resulting postoperative complications are discussed. An endocrinological appropriate follow-up of the patients is necessary.
Female↗
Novel activation stimulus of chloride channels by potassium in human osteoblasts and human leukaemic T lymphocytes.
1. The whole-cell recording mode of the patch-clamp technique was used to study the effect of extracellular K+ and Rb+ on membrane currents in human osteoblasts, in a human osteoblast-like cell line, and in the Jurkat human leukaemic T cell line. 2. Increasing the extracellular concentration of K+ increased the membrane conductance of the cells in a concentration-dependent manner. This increase in membrane conductance was due to the activation of a Cl- conductance. Rb+ also induced this conductance, but conductance was less than half that seen in K+. 3. The Cl- channel blockers 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) and 4-acetamido-4'-isothiocyanatostilbene 2,2'-disulphonic acid (SITS) blocked the K(+)-induced Cl- current in a voltage-dependent manner. The degree of blockade increased with membrane depolarization to a maximum level at 40 mV. At potentials above this value the block appeared to decrease. 4. Both tonicity and K+ were required for maximal activation of the Cl- conductance since the K(+)-induced Cl- conductance could be inhibited by hypertonic solutions and the activation of a volume-sensitive Cl- conductance by hypotonic solutions could be enhanced by extracellular K+. 5. We conclude that an outwardly rectifying Cl- conductance can be activated either upon osmotic swelling or by an increase in extracellular K+. Both activation pathways may be involved in cell volume regulation and seem to apply to volume-sensitive Cl- channels in general since we observe this phenomenon in two different cell types, in human osteoblasts as well as in human leukaemic T lymphocytes.
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗