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Biomedical subjects

A Meyer

Publications and source records attributed to A Meyer.

At least 55 records · Page 3Linked to original sources
PubMed2003

Closing of the Tethys Sea and the phylogeny of Eurasian killifishes (Cyprinodontiformes: Cyprinodontidae).

To test vicariant speciation hypotheses derived from geological evidence of the closing of the Tethys Sea, we reconstruct phylogenetic relationships of the predominantly fresh-water killifish genus Aphanius using 3263 aligned base pairs of mitochondrial DNA from samples representing 49 populations of 13 species. We use additional 11 cyprinodontid species as outgroup taxa. Genes analysed include those encoding the partial 12S and 16S ribosomal RNAs; transfer RNAs for valine, leucine, isoleucine, glutamine, methionine, tryptophan, alanine, asparagine, cysteine and tyrosine; and complete nicotinamide adenine dinucleotide dehydrogenase subunit I and II. Molecular substitution rate for this DNA region is estimated at of 8.6 +/- 0.1 x 10(-9) substitutions base pair(-1) year(-1), and is derived from a well dated transgression of the Red Sea into the Wadi Sirhan of Jordan 13 million years ago; an alternate substitution rate of 1.1 +/- 0.2 x 10(-8) substitutions base pair(-1) year(-1) is estimated from fossil evidence. Aphanius forms two major clades which correspond to the former eastern and western Tethys Sea. Within the eastern clade Oligocene divergence into a fresh-water clade inhabiting the Arabian Peninsula and an euhaline clade inhabiting coastal area from Pakistan to Somalia is observed. Within the western Tethys Sea clade we observe a middle Oligocene divergence into Iberian Peninsula and Atlas Mountains, and Turkey and Iran sections. Within Turkey we observe a large amount of genetic differentiation correlated with late Miocene orogenic events. Based on concordance of patterns of phylogenetic relationships and area relationships derived from geological and fossil data, as well as temporal congruence of these patterns, we support a predominantly vicariant-based speciation hypothesis for the genus Aphanius. An exception to this pattern forms the main clade of A. fasciatus, an euhaline circum-Mediterranean species, which shows little genetic differentiation or population structuring, thus providing no support for the hypothesis of vicariant differentiation associated with the Messinian Salinity Crisis. The two phylogenetically deepest events were also likely driven by ecological changes associated with the closing of the Tethys Sea.

Animals↗
PubMed2003

Interleukin-18 expression in BAL cells of sarcoidosis patients is decreased in vivo but protein secretion is not impaired in vitro.

Recently, increased expression of interleukin-18 (IL-18) has been shown in sarcoid airway epithelium. However, IL-18 expression has not been investigated extensively in bronchoalveolar lavage (BAL) cells in sarcoidosis yet. Expression of IL-18 and tumour necrosis factor-alpha (TNFalpha) mRNA in cells of the BAL of 23 patients with sarcoidosis and nine healthy volunteers was determined using semiquantitative RT-PCR. IL-18 protein in BAL cells was investigated by immunocytochemistry (ICC). IL-18 protein levels in BAL cell culture supernatants from patients and controls with and without LPS stimulation were measured by enzyme-linked immuno-sorbent assay. BAL cells from patients were stimulated with either IL-10 or IL-13 and IL-18 protein levels were determined. IL-18 mRNA expression was significantly decreased in BAL cells of patients compared to control subjects (1.62 +/- 0.27 vs. 4.29 +/- 0.77, P < 0.05). TNFalpha mRNA expression was significantly increased in BAL cells of patients in comparison to control subjects (0.63 +/- 0.09 vs. 0.11 +/- 0.08, P < 0.05). ICC showed less positive alveolar macrophages in sarcoidosis patients than in control subjects (26 vs. 53%). IL-18 protein levels did not differ significantly between both groups. Stimulation with IL-10 significantly reduced IL-18 protein concentration in sarcoidosis patients. Our results suggest that BAL cells may not be the main source of IL-18 production in sarcoidosis in vivo. Since IL-18 production of BAL cells was not impaired in culture antiinflammatory cytokines might contribute to decreased IL-18 expression in vivo.

Adult↗
PubMed2003

HLA-DQA1*0301-associated susceptibility for autoimmune polyglandular syndrome type II and III.

No significant differences were reported for the frequency of DR3-DQ2 and DR4-DQ8 haplotypes in a recent study of one of the largest cohorts worldwide of patients with isolated Addison's disease compared to patients with APS II. However, previous studies had suggested that the HLA-DQ genes, especially DQA1*0102, may be a genetic marker for resistance to autoimmune thyroid disease, which is the most frequent disease in APS II or III. Until now, HLA-DQA1 alleles have not been systematically investigated in APS. We determined the HLA-DR and HLA-DQA1 association in 112 unrelated patients with APS II (n = 29), APS III (n = 83) and 184 unrelated patients with single-component diseases without further manifestations of APS: Graves' disease (n = 70), Hashimoto's thyroiditis (n = 53), autoimmune Addison's disease (n = 15), vitiligo (n = 16) and alopecia (n = 30), and 72 healthy controls - German Caucasians - to identify possible predisposing and protective HLA class II alleles in APS. In agreement with previous studies, we detected a significantly higher frequency of DR 3 and/or DR 4 in patients with APS II and III compared to controls. In patients with APS II, we detected a significantly higher frequency of DQA1*0301 and *0501 compared to controls confirming the increased frequency of an extended HLA DRB1-*04-DQA1-*03-DQB-*03 haplotype as previously described. In contrast, only DQA1*0301 was increased in our patients with APS III compared to controls. Moreover, we detected an increased frequency of DQA1*0301 in patients with APS, whereas DQA1*0301 was only significantly elevated in alopecia in patients with single-component diseases without APS. Therefore, our results indicate an association between DQA1*0301 and APS II or III since this allele was otherwise not significantly associated with any of its component diseases except alopecia. Moreover, our data imply that the allele DQA1*0301 is a marker of increased risk for further APS manifestations in patients who suffer from an organ-specific autoimmune disease.

Addison Disease↗
PubMed2003

[Surgical treatment for hilar cholangiocarcinoma (Klatskin's tumor)].

Surgical treatment of hilar bile duct carcinoma remains difficult, which is due to the inadequate possibilities in assessing tumor extent during the preoperative diagnostic procedure as well as intraoperatively. Radical resection with negative histologic margins offers the best chance for long-term survival. The decision regarding the appropriate surgical approach is challenging due to the complexity of tumor localization and neighboring vascular structures. Aggressive resection demands extended liver resection, which is associated with the risk of postoperative liver failure. However, even limited surgery such as hilar resection can be curative and leads to long-term survival in individual cases. The principles of surgical oncology have led to more aggressive procedures, including the combination of liver transplantation and multivisceral resection, and can be performed with calculable morbidity and mortality. Nevertheless, the high risk of tumor recurrence under long-term immunosuppression, the limited availability of donor organs and the excellent results of liver transplantation in non-malignant diseases do not justify this procedure at present. Neoadjuvant radiochemotherapy has failed to demonstrate major benefit. In patients with irresectable tumor or distant metastases palliative measures are aimed at restoring an unobstructed bile flow with endoscopic placement of metal stents. Palliative treatment with additional radio- or photodynamic therapy may be considered in individual cases.

Adult↗
PubMed2003

Use of a phage-based assay for phenotypic detection of mycobacteria directly from sputum.

The phage amplified biologically assay is a new method for rapid and low-cost phenotypic determination of the drug sensitivities of Mycobacterium tuberculosis isolates and the detection of viable organisms in patient specimens. Infection of slowly growing mycobacteria with phage (phage D29) was followed by chemical virucide destruction of extracellular phage. Infected mycobacteria were mixed in culture with rapidly growing sensor cells, which the phage can also infect; i.e., lytic amplification of phage occurs. The aims of the present study were to optimize the speed and sensitivity of the assay and reduce its cost for developing countries by using an M. tuberculosis-spiked sputum model with (i). identification of inhibitory components of sputum and optimization of decontamination methods; (ii). simplification of the washing and development steps; (iii). reduction of the use of high-cost components, e.g., oleate-albumin-dextrose-catalase (OADC) supplement; and (iv). optimization of virucide treatment. The following results were obtained. (i). An inhibitory factor in sputum which could be removed by treatment of the sample with sodium dodecyl sulfate or NaOH decontamination was identified. (ii). A microcentrifuge-based approach with thixotropic silica as a bedding and resuspension agent was developed as an alternative to conventional centrifugation medium exchange. The yield was increased 228-fold, with increased speed and reduced cost. (iii). At present, after extracellular inactivation of phage, the ferrous ammonium sulfate (FAS) virucide is sequestered by dilution with an expensive supplement, OADC. Sodium citrate with calcium chloride was found to be a cost-effective after treatment with the FAS protectant and offered greater protection than OADC. Kinetic-lysis experiments indicated that an infection time of 1 to 3 h prior to FAS addition was optimal. (iv). Amplification of the signal (which corresponded to the burst size) was shown by allowing lysis prior to plating in a spiked medium model (up to 20-fold) and a spiked sputum model (up to 10-fold). A liquid culture detection method capable of detecting approximately 60 viable M. tuberculosis organisms in 1 ml of sputum was developed. Taken together, these improvements support the routine application of the assay to sputum specimens.

Bacteriophages↗
PubMed2003

Increased interleukin-13 expression in patients with sarcoidosis.

BACKGROUND: Sarcoidosis is a systemic granulomatous disorder of unknown origin. Lymphocytic inflammation is dominated by expression of Th1 type cytokines such as tumour necrosis factor alpha (TNFalpha). Interleukin 13 (IL-13) is a Th2 cytokine which is expressed by CD4+ T cells and has been shown to suppress TNFalpha in human blood monocytes. The role of IL-13 as a possible anti-inflammatory cytokine in sarcoidosis was investigated. METHODS: mRNA expression of IL-13, IL-4, IL-10, and TNFalpha in bronchoalveolar lavage (BAL) fluid cells and peripheral mononuclear blood cells (PBM) of 18 patients with sarcoidosis and nine healthy controls was assessed using RT-PCR. In addition, IL-13 protein levels in BAL cell culture supernatants from 12 patients and all controls were measured and immunocytochemistry of IL-13 protein was performed in BAL fluid cells of eight patients. TNFalpha concentrations were measured with and without stimulation with recombinant human (rh) IL-13, rhIL-10, and lipopolysaccharide (LPS). RESULTS: IL-13 mRNA expression was significantly increased in BAL cells and PBM of patients compared with controls (p<0.05). No significant difference was found in IL-4 mRNA or IL-10 mRNA expression in BAL fluid cells or PBM between the two groups. TNFalpha mRNA expression was significantly higher in BAL fluid cells of patients than controls (p<0.05). IL-13 protein levels in BAL cell culture supernatants were slightly raised in half the patients investigated but in only two controls. Immunocytochemistry detected IL-13 protein in alveolar macrophages of patients. IL-13 led to decreased TNFalpha concentrations (p<0.05). CONCLUSIONS: IL-13 expression is increased in BAL cells and PBM in sarcoidosis and IL-13 is secreted from BAL cells. Alveolar macrophages may be the cellular source. These data suggest that IL-13 might have an anti-inflammatory effect by acting on TNFalpha.

Adult↗
PubMed2003

[Multilocular eyelid hidrocystoma: an anatomical and clinical observation].

A cystic cutaneous mass was observed on the lateral canthus of the left eyelid in a 25-year-old woman, 2 years after being operated on for a lesion that had existed in the same area several years before, but the patient could not identify its nature. The present mass appeared as a well-circumscribed bluish cystic lesion. A surgical resection was performed; pathological analysis disclosed a cystic sweat tumor composed of several contiguous cysts. One year of follow-up has revealed no complications.

Adult↗
PubMed2003

[Inflammatory pseudotumor of the caruncle].

A 6-year-old girl exhibited a recent caruncular tumor which was increasing in size. It was removed after a CT scan had showed a both medial and superficial mass. Fortunately, histological tests only found inflammatory cells attesting that the mass was due to an inflammation of this area. Inflammation is one of the different processes that may increase the size of the caruncle, but sometimes, only histopathology can provide conclusive evidence.

Child↗
PubMed2003

[Hypertrophic eyelid conjunctival scar. A tarsal keloid].

The clinicopathologic case of a 53-year-old female patient with an abnormal tumor growing on the mucous part of the superior right eyelid is reported. The patient was operated on for ten years ago and a whitish mass slowly developed on the conjunctival face of the eyelid disturbing the use of corneal lenses. It was hard, painless and had the shape of a flat mushroom. The removal was performed under local anesthesia and allowed us to resect a hard and fibrous lesion. Histopathology showed that the lesion was made of a fibrous tissue organized like a hypertrophic scar. Surgical treatment of chalazion is frequent and rarely gives rise to abnormal scarring.

Cicatrix↗
PubMed2003

[Conjunctival semi-lunar fold nevus of presumed late onset].

Conjunctival nevi are lesions observed commonly occasionnally and can be found later in a life. Such a lesion was observed on the conjunctival semilunar fold in a 76-year-old female patient. It was oval in shape, pigmented, and was mainly visible when the affected eye was in abduction. As no accurate anterior clinical history was available, surgical resection was performed. Hitopathological study disclosed a subepithelial nevus, which was completely resected. Regular follow-up was recommended, as is usual after surgical resection of a conjunctival pigmented tumor.

Aged↗
PubMed2003

[Pseudotumoral eyelid inflammation. Apropos of an anatomo-clinical case].

A clinicopathological case of a 76-year-old male patient with a chronic inflammatory change of the inferior left eyelid is reported. The inflammation appeared as a reddish area of the inner part of the eyelid, without sharp limits, but with loss of lashes. Numerous local treatments did not to cure this condition. As some true eyelid tumors may mimic an inflammation during growth and, for example, sebaceous carcinoma may clinically present as chronic unilateral blepharitis, a surgical excisional biopsy was performed on this left eyelid. Its histopathological study showed a granulomatous inflammation, which was typical of a simple chalazion. This case clearly illustrates that the chalazion may not always appear as a limited nodular inflammation of the eyelid, but may have a more diffuse clinical presentation.

Aged↗
PubMed2003

[Corneal edema in pseudophakia. A case report].

Pseudophakic bullous keratopathy is one of the most common complications of intraocular lenses, which explains the high rate of this condition in series of patients experiencing corneal grafts. It is caused by irreversible damage to the endothelial layer of the implanted eye involving the artificial lens, and occurs either during cataract extraction or after the operation. Intraoperative endothelial protection and the choice of an appropriate lens may contribute to decreasing this secondary disease, which can have severe consequences for many patients whose corneal graft may not restore their visual potential as well as expected. We report a clinicopathological case of a 59-year-old male, previously operated on for cataract in both eyes with an anterior chamber lens. A bilateral corneal edema occurred a few years after the operation, with a bilateral decrease in vision as a consequence. A corneal graft was performed in 2000 on the left eye in order to improve the patient's visual autonomy. The best treatment of this condition remains prevention, avoiding the use of this type of intraocular lens, whose main complication is corneal edema.

Cataract Extraction↗
PubMed2003

[Conjunctival pyogenic granuloma in a patient with chalazions].

A 28-year-old male patient had a chalazion on his left eyelid. Increased discomfort led to the discovery of a conjunctival mass under the inner part of his upper eyelid. On clinical examination, a small reddish mass on the palpebral conjunctiva of the upper left eyelid was only visible on the underside of the lid; the mass was diffusely reddish. Additionally, a chalazion was present in the middle of the lower left eyelid. As this condition was a source of discomfort to the patient, the mass was surgically resected. The histological study found a typical pyogenic granuloma, a possible complication in the course of a chalazion.

Adult↗
PubMed2002

A multicenter survey of complications associated with 21,676 operative hysteroscopies.

OBJECTIVE: The following study analyses the hysteroscopic experience of multiple gynecologic centers throughout Germany in regard to the incidence of complications, the therapy of these complications and anesthesiological management during 21,676 hysteroscopic procedures. METHODS AND MATERIAL: Under the supervision of the German Society of Gynecology Endoscopy, 92 hysteroscopic centers were evaluated and the following information was collected: hysteroscopic experience in years, number of surgical hysteroscopies per year, total number of operative hysteroscopies, types of hysteroscopic procedures, intra- and post-operative complications. RESULTS AND CONCLUSION: The results of the study show that in most German centers, hysteroscopy is just being established. Nevertheless, the rate of complications such as perforation of the uterus, fluid-overload syndrome, infection and perioperative bleeding is small. This may be due to the high proportion of documented procedures performed by the more experienced centers.

Blood Loss, Surgical↗
PubMed2002

Circulating concentrations of asymmetrical dimethyl-L-arginine are increased in women with previous gestational diabetes.

AIMS/HYPOTHESIS: The concentration of asymmetrical dimethyl- L-arginine (ADMA), an endogenous inhibitor of the nitric oxide synthase, is increased in patients at risk or with cardiovascular disease. We have investigated ADMA concentrations in women with a history of gestational diabetes (GDM), who could develop endothelial dysfunction and Type II (non-insulin-dependent) diabetes mellitus after delivery, and in healthy control subjects. METHODS: Previous GDM patients were grouped according to their BMI as obese (> or =25 kg/m(2), n=46) or non-adipose (<25 kg/m(2), n=31). Serum samples were taken 14 to 16 weeks after delivery and after 1 year. The control group comprised 17 healthy women (BMI<25 kg/m(2)). ADMA concentrations were analysed by high performance liquid chromatography. RESULTS: ADMA concentrations were comparable between obese and non-adipose GDM patients (0.58+/-0.02 and 0.57+/-0.02 micro mol/l, respectively), and higher than in the control group (0.47+/-0.03 micro mol/l; p<0.006). Insulin resistance as estimated by the insulin sensitivity index was more frequent among the obese than the non-adipose GDM women (p<0.05) and control subjects (p<0.05, both). No change in ADMA concentrations was found after 1 year in women with GDM. There was only a slight correlation between ADMA and BMI (r=0.26, p<0.02), triglycerides (r=0.29, p<0.004), or fasting plasma glucose (r=0.21, p<0.05), and not with the insulin sensitivity index or other parameters. In a multiple regression analysis ADMA serum concentrations were only associated with triglycerides. CONCLUSION/INTERPRETATION: Circulating ADMA concentrations are increased in normoglycaemic women with previous GDM. This increase is independent from other risk factors or surrogate markers for diabetes or cardiovascular events.

Adult↗
PubMed2002

Use of MALDI-TOF mass spectrometry to monitor solid-phase synthesis of oligonucleotides.

MALDI-TOF mass spectrometry has been used to characterize solid-supported oligonucleotides containing natural and non-natural and non-nucleoside moieties and a variety of internucleosidic linkages including phosphate and phosphite triesters and H-phosphonate diesters. This technique was used to follow the reactions involved in oligonucleotide synthesis; this enabled direct control of the elongation and optimization of the coupling process.

Base Sequence↗
PubMed2002

The role of neoadjuvant chemotherapy and interval laparotomy in advanced ovarian cancer.

Radical debulking surgery allows for optimal cytoreduction in less than 50% of patients with advanced ovarian cancer. In spite of highly efficient chemotherapeutic regimens, the prognosis of patients with residual tumor masses larger than 1 cm in diameter following staging laparotomy is very poor. This observation led to the initiation of numerous trials evaluating the feasibility and efficiency of the use of primary chemotherapy followed by interval laparotomy in women with advanced ovarian cancer. The available data is presented and discussed in this review.

Antineoplastic Combined Chemotherapy Protocols↗