PERIORAL DERMATITIS: STILL A THERAPEUTIC CHALLENGE.

Perioral dermatitis is a common and often chronic dermatosis. In its classic form, it primarily affects women aged 15 to 45 years, but there are also variants including lupus-like and granulomatous perioral dermatitis, where granulomatous form is more common in childhood and affects mostly prepubescent boys. The etiopathogenesis of the disease remains unclear, but there is a frequent finding of prolonged use of topical products, especially corticosteroids, in the treatment of rosacea and seborrheic dermatitis, preceding the clinical manifestation of perioral dermatitis.

Pulmonary tumorlets with surrounding fibrous tissue--suspected carcinoma: case report and review of the literature.

Pulmonary tumorlets are small, often multiple nodular proliferations of pulmonary neuroendocrine cells. They are common incidental findings in chronic inflammatory pulmonary diseases. They can also be found in normal lung parenchyma and as one part of the continuum known as diffuse idiopathic pulmonary neuroendocrine cell hyperplasia.

Advances in a rapidly emerging field of hair follicle stem cell research.

Human skin maintains the ability to regenerate during adulthood, as it constantly renews itself throughout adult life, and the hair follicle (HF) undergoes a perpetual cycle of growth and degeneration. The study of stem cells (SCs) in the epidermis and skin tissue engineering is a rapidly emerging field, where advances have been made in both basic and clinical research. Advances in basic science include the ability to assay SCs of the epidermis in vivo, identification of an independent interfollicular epidermal SC, and improved ability to analyze individual SCs divisions, as well as the recent hair organ regeneration via the bioengineered hair follicular unit transplantation (FUT) in mice.

[Pleural mesothelioma--case report].

Pleural mesothelioma is a rare neoplasm with the incidence of 1-2 per million people. The incidence is higher in male population (10-30/million), whereas the incidence in female population is 2 per million. It occurs predominantly at older age (65+ years).

[Erythroblasts in the peripheral blood of adult patient as an adverse prognostic sign--a case report].

Red blood cells (RBC) normally lose their nuclei before appearing in peripheral blood. After having undergone differentiation in bone marrow, blood cells must cross the blood-marrow barrier to enter the bloodstream. Erythroblasts, or nucleated red blood cells (NRBC), do not distort easily, so they cannot escape this barrier.

Ehlers-Danlos syndrome type IV (EDS IV) as model of a defective biopolymer composite material.

The connective tissue of a lethal EDS IV case was investigated for the reasons of the manifested disturbances of the arterial wall. This functional disorder was attributed to the mechanical decoupling of elastin and collagen, with the premise of a composite material consisting of cellular, fibrillar, lamellar and other matrix components. A conceivable relation between the manifested deficiency of type III collagen and a disturbed anchoring of elastin is shown.

Twisted fibrils are a structural principle in the assembly of interstitial collagens, chordae tendineae included.

X-ray diffraction analysis of connective tissue samples, which contain type I and type III collagen shows that twisted collagen fibrils are a general principle of assembly. The occurrence of twisted fibrils in native wet Chordae tendineae, skin and Aorta is combined with a shorter axial periodicity of about 65 nm. This shorter D period is shown to be directly related to the tilt of the molecules, which have to be curved to build-up twisted fibrils.

Structural dynamic of native tendon collagen.

The dynamic behaviour of collagen fibrils is revealed by time-resolved X-ray investigations of native rat tail tendon fibres in tensile tests.

The macromolecular structure of collagen in tendon fibres of dermatosparactic animals.

Small-angle x-ray diffraction spectra of dermatosparactic tendon collagen show a decreased intensity of the first order reflection. We interprete this finding to be due to the N-terminal propeptide which fills the intermolecular gap region partially.

New aspects of the etiology of tendon rupture. An analysis of time-resolved dynamic-mechanical measurements using synchrotron radiation.

Native collagen fibers were exposed to different dynamic loads to simulate damage to tendons and ligaments relevant clinically and for sports medicine. The results suggest that the rupture of a tendon is caused at the submicroscopic fibrillar level. Not only slow or very fast elongation, but also very fast unloading of stretched fibers seems to be responsible for disseminated damage, which reduces the stability of a fiber.

Stress-induced molecular rearrangement in tendon collagen.

Tension-induced molecular rearrangements in wet native fibres of rat-tail tendons and human finger flexor tendons are registered with the help of time-resolved diffraction spectra using synchrotron radiation. The tension-induced increase of the 67 nm D period is combined with changes in the intensities of some orders of the meridional small angle reflection. Both effects are reversible when unloading the fibre, but are preserved when the load is held constant until the fibre tears.

Packing of collagen molecules modified with 2-propanol.

X-ray diffraction data of collagen molecules modified with 2-propanol favour a quasi-hexagonal lateral packing over a quasi-tetragonal one.

Transformation of the structure of collagen. A time-resolved analysis of mechanochemical processes using synchrotron radiation.

Mechanochemically induced molecular transformations of collagen fibres were analysed using time-resolved small-angle diffraction spectra and histomechanical measurements. In particular, the influence of aqueous and methanolic perchlorate solutions was examined. According to a transformation continuing from the periphery towards the centre, the macroscopic contraction that is completed less than five minutes after incubation with perchlorate is caused by peripherally transformed fibrils only, whereas the centrally situated fibrils first undergo an accordion-like folding, but after more than 20 minutes are transformed similarly.