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Biomedical subjects

A Meyer

Publications and source records attributed to A Meyer.

At least 73 records · Page 4Linked to original sources
PubMed2002

TNFalpha, interleukin-10 and interleukin-18 expression in cells of the bronchoalveolar lavage in patients with pulmonary complications following bone marrow or peripheral stem cell transplantation: a preliminary study.

Pulmonary complications pose a major clinical problem after bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT). The underlying pathophysiological mechanisms are under investigation. Twenty patients with infectious or non-infectious pulmonary complications after BMT or PBSCT underwent bronchoalveolar lavage (BAL) and tumor necrosis factor-alpha (TNFalpha), interleukin-10 (IL-10) and interleukin-18 (IL-18) mRNA expression was determined in BAL cells in comparison to 11 healthy volunteers. Patients were divided into two groups (infectious pneumonia, n = 14 or idiopathic pneumonia syndrome (IPS)/bronchiolitis obliterans (BO), n = 6). TNFalpha expression was significantly increased in both patient groups compared to the control (0.40 +/- 0.07 and 0.39 +/- 0.09 vs 0.15 +/- 0.05; P < 0.05; semiquantitative PCR analysis; mean +/- s.e.m.). IL-10 expression was significantly elevated the group of patients with infectious pneumonia in comparison to normal controls (0.15 +/- 0.06 vs 0.01 +/- 0.01; P < 0.05) but not in patients with IPS/BO (0.05 +/- 0.04; P > 0.05). However, IL-10 was not expressed in BAL cells of all patients and control individuals. IL-18 expression was significantly decreased in the both patient groups (1.47 +/- 0.24 and 1.79 +/- 0.63) in comparison to the control group (4.29 +/- 0.77; P < 0.05). Survival analysis showed a significant association between elevation of TNFalpha and poor prognosis (P < 0.05). These results highlight the immunoregulatory disturbances in the lungs after BMT/PBSCT.

Adult↗
PubMed2002

Exploring the potential of life-history key innovation: brook breeding in the radiation of the Malagasy treefrog genus Boophis.

The treefrog genus Boophis is one of the most species-rich endemic amphibian groups of Madagascar. It consists of species specialized to breeding in brooks (48 species) and ponds (10 species). We reconstructed the phylogeny of Boophis using 16S ribosomal DNA sequences (558 bp) from 27 species. Brook-breeders were monophyletic and probably derived from an ancestral pond-breeding lineage. Pond-breeders were paraphyletic. The disparity in diversification among pond-breeders and brook-breeders was notable among endemic Malagasy frogs, although it was not significant when considering Boophis alone. Sibling species which have different advertisement calls but are virtually indistinguishable by morphology were common among brook-breeders; genetic divergence between these species was high (modal 8% total pairwise divergence). Substitution rates in brook-breeding species were significantly higher than in pond-breeders. Speciation of pond-breeders may be hindered by their usually more synchronous reproduction and a higher vagility which enhances gene flow, while a higher potential of spatial segregation and speciation may exist along brooks.

Animals↗
PubMed2002

[Primary and secondary aortoiliac reconstructions in patients with coexistent horseshoe and pelvic kidney].

The coexistence of dystopic kidney and abdominal aortic aneurysm or aortoiliac occlusive arterial disease is uncommon (0.12-0.15 %) and constitutes a technical challenge to vascular surgeons. Between 1997 and 1999 we performed 249 aortoiliac reconstructions and encountered four patients (1.6 %) with dystopic kidneys. The aortoiliac reconstructions were performed successfully in all patients while maintaining renal blood supply. Aortoiliac reconstructions in patients with horseshoe or pelvic kidney show similar results as regular reconstructions on the condition that optimal preoperative diagnosis and operative technique are used considering atypical renal vessels. Nevertheless, pelvic kidneys can lead to serious complications as we describe in this report. On the basis of our patients anatomy, embryology and surgical management of this entity.

Aged↗
PubMed2002

[Participation of asthmatic children in gymnastic lessons at school].

INTRODUCTION: Exercise is a predominant stimulus leading to bronchial obstruction in asthmatic children. Therefore physicians, teachers and parents still have a negative attitude towards physical exercise of asthmatic children in school. We investigated the attendance of girls and boys with asthma during sport-lessons at school. METHODS: 254 teachers who give lessons in sports in 46 different schools (high school, primary and secondary school) in Hamburg were asked about their knowledge of the disease and how often and in which manner asthmatic children participated their sport-lessons. RESULTS: Teachers estimated that in each class (average: 25 - 30 children) approximately 1 asthmatic is present. 60 % of these asthmatics take part likewise their healthy peers. 40 % either take part only sometimes (12,6 %) or specific elements (25,2 %) or not at all (12,2 %). Most of the teachers assessed their knowledge about the disease as medium good. In contrast, only 4,7 % of them had a specific plan that allows asthmatics to participate sport-lessons without getting obstructive. CONCLUSION: Asthmatic children are underestimated in school and participate in only 60 % equally to their healthy peers at sport-lessons. The knowledge about this most frequent chronic disease in children could be increased. Better training of teacher-students and teachers is recommended.

Asthma↗
PubMed2002

The core of bluetongue virus binds double-stranded RNA.

Double-stranded RNA (dsRNA) viruses conceal their genome from the host to avoid triggering unfavorable cellular responses. The crystal structure of the core of one such virus, bluetongue virus, reveals an outer surface festooned with dsRNA. This may represent a deliberate strategy to sequester dsRNA released from damaged particles to prevent host cell shutoff.

Binding Sites↗
PubMed2002

[Basal cell carcinoma associated with a squamous cell papilloma at the inner part of the eyelid].

There are numerous variants of cutaneous tumors involving the eyelids. Tumors of a different nature may at times be observed simultaneously in the same area of the eyelid. A clinicopathologic case of a 36-year-old male patient with 2 different cutaneous tumors at the nasal part of the left eyelid is reported. One was a nodular tumor on the inner canthus with a pearly appearance; the other had a papillomatous pattern. After surgical removal, the histopathological study of the tumors disclosed a typical basal cell carcinoma and a squamous cell papilloma. Both tumors can be commonly observed on the eyelids and surgical excision cured the patient.

Adult↗
PubMed2002

[Eyelid neurofibroma affecting a young woman].

A 43-year-old female patient had an amelanotic single tumor thickening the upper right eyelid and observed since early childhood. Clinically, it appeared as a firm mass, without sharp margins, giving a thickened appearance to the superior eyelid. The ophthalmic clinical examination was normal but some subcutaneous nodules attested to the diffusion of the disease recognized as a limited form of neurofibromatosis 1. Although well tolerated, it gave rise to a cosmetic disturbance and the patient was willing to undergo an excision. A complete surgical excision was performed on the lesions and the pathological study disclosed a typical neurofibroma. Regular observation of the different cutaneous nodules was recommended.

Adult↗
PubMed2002

[Eyelid precancerous keratosis].

A 25-year-old-male patient had one keratinized tumor on the inferior right eyelid, first observed 5 months before. Its size had been increasing for the last three weeks. The visual function was normal. Clinical examination disclosed a papillomatous lesion on the cutaneous middle part of the eyelid. A surgical excision was performed under local anesthesia. The histopathological study found a papillomatous epidermal proliferation with both structural and cytological atypias, concluding with a precancerous keratosis of the eyelid.

Adult↗
PubMed2002

[Seborrheic keratosis of the eyelid in a young woman].

A 46-year-old female patient had a tumor of the free margin area of the superior right eyelid, appearing as the fourth recurrence of a primary lesion, occurring 24 years before. The lesion was covered with a thick layer of keratin, giving it a grayish and black color. Excision was performed without involving the free margin. Histopathology disclosed that the tumor was a seborrheic keratosis, which was not completely removed. As the lesion was benign, no further surgery was performed but regular examination was recommended to the patient.

Eyelid Diseases↗
PubMed2002

[Nevus mimicking a basal cell carcinoma of the eyelid].

A clinicopathologic case of a 41-year-old female patient exhibited a single cutaneous tumor at the inner part of the free margin of the inferior left eyelid. It was a pink, fleshy, and nodular well-circumscribed exophytic mass with thin vessels on its surface. Experienced already for 20 years, this lesion had been observed 6 years before and has not exhibited much change since then. However, its clinical appearance argued for a possible small basal cell carcinoma, which had grown over the inferior left lachrymal duct. After surgical removal, histopathology showed that the tumor was an amelanotic dermal nevus. No disturbance of lachrymal drainage was observed after surgery. This case shows that nodular amelanotic tumors of the eyelid, even when located on the inner segment of the eyelid, may be a nevus.

Adult↗
PubMed2002

[Followup of chicken pox keratitis. Anatomic-clinical case report].

Chicken pox is a very common infectious disease in children. Its corneal involvement is less serious than with measles, which may lead to blindness in numerous developing countries. However, with occasional cases occur. A case of a 59-year-old male patient whose left cornea was involved during a chicken pox infection at the age of 7 is reported. More recently, the vision of the right eye was normal at 20/20 and reduced to visual perception in the affected left eye. Corneal sensitivity was maintained in the left eye, which, however exhibited a central epithelial defect. A central round opacity of the left corneal stroma was believed to be the scar resulting from a previous disciform keratitis. The left central cornea was thinned and there was neither an anterior chamber flare nor new corneal vessels. This corneal condition required a corneal allograft, performed quickly because of the potential risk of perforation. Histopathological study of the corneal button showed a central corneal thinning with an increase in epithelial thickness. The corneal stroma was disorganized, with irregular collagen bundles. No inflammatory cells could be observed, however. All the histopathological changes observed were those of a corneal scar.

Chickenpox↗
PubMed2002

[Bilateral keratoconus: a case report].

Among corneal dystrophies, the keratoconus is one of the most frequently observed among young adults. A clinico pathological case is reported in a 13-year-old-girl of African origin. The diagnosis of bilateral keratoconus was established based on the obvious changes of the corneal curvature and thickness. After an unsuccessful attempt to improve vision with contact lenses, a keratoplasty was finally performed on one side to remove the pathological cornea. Its histopathological study found the characteristic changes of keratoconus: breaks of Bowman's layer and corneal thinning.

Adolescent↗
PubMed2002

[Inflammation of an ectopic pinguecula].

An 80-year-old male patient experienced recently diagnosed swelling of the limbal conjunctiva. In his clinical history were found cataract surgery on the right eye 3 months before, chronic open angle glaucoma effectively treated by local eye drops, treated systemic hypertension and hypercholesterolemia. On ophthalmic examination, a conjunctival mass was present in the inferior lateral conjunctival quadrant next to the limbus, with numerous vessels visible at its top. Treatment with topical corticosteroids failed to obtain regression, but decreased the local inflammatory signs. The persistence of the mass led to its surgical excision under local anesthesia. Histopathology found a subepithelial accumulation of modified collagen bundles typical of elastotic degeneration. Capillary vessels were seen in the superficial subepithelial area, attesting to the high degree of vascularization observed clinically. The final diagnosis was a pinguecula, which was not exactly located on the horizontal meridian area as it is usual.

Aged↗
PubMed2002

[Actinic keratosis seborrheic wart and nevus: three distinct cutaneous eyelid skin lesions in a single patient].

A 67-year-old woman had three different tumors of the eyelids. The most prominent one was a nevus of the free margin of the inferior left eyelid. The nevus was followed for 18 months without change while two epidermal papillomatous tumors grew and were surgically removed. Histopathology disclosed that one tumor was a seborrheic keratosis and the other was a pre-epitheliomatous keratosis. Histologic evaluation of the margins showed that surgical removal was complete. A regular examination of the scars was recommended to the patient.

Aged↗
PubMed2001

Comparative genomics provides evidence for an ancient genome duplication event in fish.

There are approximately 25 000 species in the division Teleostei and most are believed to have arisen during a relatively short period of time ca. 200 Myr ago. The discovery of 'extra' Hox gene clusters in zebrafish (Danio rerio), medaka (Oryzias latipes), and pufferfish (Fugu rubripes), has led to the hypothesis that genome duplication provided the genetic raw material necessary for the teleost radiation. We identified 27 groups of orthologous genes which included one gene from man, mouse and chicken, one or two genes from tetraploid Xenopus and two genes from zebrafish. A genome duplication in the ancestor of teleost fishes is the most parsimonious explanation for the observations that for 15 of these genes, the two zebrafish orthologues are sister sequences in phylogenies that otherwise match the expected organismal tree, the zebrafish gene pairs appear to have been formed at approximately the same time, and are unlinked. Phylogenies of nine genes differ a little from the tree predicted by the fish-specific genome duplication hypothesis: one tree shows a sister sequence relationship for the zebrafish genes but differs slightly from the expected organismal tree and in eight trees, one zebrafish gene is the sister sequence to a clade which includes the second zebrafish gene and orthologues from Xenopus, chicken, mouse and man. For these nine gene trees, deviations from the predictions of the fish-specific genome duplication hypothesis are poorly supported. The two zebrafish orthologues for each of the three remaining genes are tightly linked and are, therefore, unlikely to have been formed during a genome duplication event. We estimated that the unlinked duplicated zebrafish genes are between 300 and 450 Myr. Thus, genome duplication could have provided the genetic raw material for teleost radiation. Alternatively, the loss of different duplicates in different populations (i.e. 'divergent resolution') may have promoted speciation in ancient teleost populations.

Animals↗
PubMed2001

Antigen-specific modulation of an immune response by in vivo administration of soluble MHC class I tetramers.

Soluble MHC/peptide tetramers that can directly bind the TCR allow the direct visualization and quantitation of Ag-specific T cells in vitro and in vivo. We used HY-D(b) tetramers to assess the numbers of HY-reactive CD8+ T cells in HYTCR-transgenic mice and in naive, wild-type C57BL/6 (B6) mice. As expected, tetramer staining showed the majority of T cells were male-specific CD8+ T cells in female HY-TCR mice. Staining of B6 mice showed a small population of male-specific CD8+ T cells in female mice. The effect of administration of soluble MHC class I tetramers on CD8+ T cell activation in vivo was unknown. Injection of HY-D(b) tetramer in vivo effectively primed female mice for a more rapid proliferative response to both HY peptide and male splenocytes. Furthermore, wild-type B6 female mice injected with a single dose of HY-D(b) tetramer rejected B6 male skin grafts more rapidly than female littermates treated with irrelevant tetramer. In contrast, multiple doses of HY-D(b) tetramer did not further decrease graft survival. Rather, female B6 mice injected with multiple doses of HY-D(b) tetramer rejected male skin grafts more slowly than mice primed with a single injection of tetramer or irradiated male spleen cells, suggesting clonal exhaustion or anergy. Our data highlight the ability of soluble MHC tetramers to identify scarce alloreactive T cell populations and the use of such tetramers to directly modulate an Ag-specific T cell response in vivo.

Animals↗