Maria Rita Mondello

Antiulcer activity of Opuntia ficus indica (L.) Mill. (Cactaceae): ultrastructural study.

In Sicily folk medicine, Opuntia ficus indica (L.) Mill. cladodes are used for the treatment of gastric ulcer. We studied the effect of administration of lyophilized cladodes on experimental ethanol-induced ulcer in rat. In this paper, we report the ultrastructural observations of gastric mucosa. The ultrastructural changes were observed by trasmission electronic microscopy (TEM) confirming the protective effect exercised by administration of lyophilized cladodes. Pre-treatment test in rats revealed a protective action against ethanol-induced ulcer. Probably, the mucilage of Opuntia ficus indica is involved.

Effects of Teucrium divaricatum Heldr. ssp. divaricatum decoction on experimental ulcer in rats.

The effects of chronic intragastric administration of the aerial parts decoction of Teucrium divaricatum Heldr. ssp. divaricatum (Labiateae) on experimental acetylsalicylic acid (ASA)-induced ulcer were studied in rats. The ulcer index and histological mucosa regeneration were evaluated. The ulcer index significantly decreased (U.I. 1.7+/-1.5; P<0.05) after treatment with a lyophilized decoction of T. divaricatum (500 mg/kg os), once daily for 7 days, compared to the control (U.I. 11.4+/-2.3). The ultrastructure modifications of gastric mucosa were observed by transmission electronic microscopy (TEM) confirming the antisecretory effect exercised by administration of the T. divaricatum decoction. Treatment with T. divaricatum seems to block up parietal cell acid secretion and to stimulate in the chief cells the formation of zymogen granules.

Behaviour of laminin 1 and type IV collagen in uninvolved psoriatic skin. Immunohistochemical study using confocal laser scanning microscopy

Previous studies have demonstrated the presence in psoriatic lesions of ultrastructural and molecular alterations of the basement membrane and an altered polarized distribution of the integrins; this latter alteration has also been observed in uninvolved skin. The aim of the present study was to determine, by means of immunolocalization with monoclonal antibodies directed against laminin 1 and type IV collagen and using confocal scanning laser microscopy, whether there are also alterations of the main components of the basement membrane in uninvolved skin. The findings showed a discontinuous and fragmented staining of laminin 1 and a normal distribution of type IV collagen. Taking into account both these results and the results of studies on epithelial cell lines, the authors hypothesize the existence of a functional deficit in psoriatic keratinocytes affecting the synthesis of the α1 subunit of laminin. This deficit would explain: (1) the incapacity to produce mature trimeric laminin; (2) the altered assembly into a distinct basal lamina; (3) the loss of keratinocyte adhesion to the basement membrane; (4) alterations in the polarized distribution of the integrins; and (5) the consequent total or partial block of the cell signals regulating the processes of cytomorphosis. Already present in uninvolved skin, and enhanced by various irritative stimuli, this situation could be decisive for the appearance of psoriatic lesions.

Immunohistochemical study of epidermal nerve fibres in involved and uninvolved psoriatic skin using confocal laser scanning microscopy.

Abstract Psoriasis is a typical hyperproliferative epidermal disease whose aetiopathogenesis is still to be defined. One of the most likely hypotheses is that it has a neurogenic origin correlated with an altered release of some neuropeptides by sensitive cutaneous nerves via antidromic pathways. As there are conflicting reports about the existence of cutaneous nerve alterations in psoriasis, we carried out an immunolocalization study using the protein gene product 9.5 as a marker for neuronal structures observed by confocal laser scanning microscopy in order to determine the pattern of sensory nerves in psoriatic skin. The investigation was carried out on cutaneous biopsies taken from involved (mature and long-established lesions) and uninvolved skin of ten patients with extensive chronic plaque psoriasis. In uninvolved psoriatic skin a significant decrease in epidermal nerve fibres was found, a further decrease was observed in mature lesions and almost a complete lack of epidermal nerve fibres in long-established psoriatic lesions. The reduction in epidermal nerve fibres and the consequent loss of relationship between these nerve structures and the skin immunocompetent cells (antigen-presenting cells, Langerhans cells, keratinocytes) might be a factor of fundamental importance in the self-maintenance of the disease.

IMMUNOLOCALIZATION OF THE COSTAMERES IN HUMAN SKELETAL MUSCLE FIBERS : CONFOCAL SCANNING LASER MICROSCOPE INVESTIGATIONS

The costameres in skeletal muscle fibers were first described by Pardo et al. (1983a) and have been defined as transverse circumferential elements of the cytoskeleton associated to the sarcolemma. Specific immunostaining for vinculin shows that the costameres overlie I bands. However, an exact correlation between the costameres and the Z line is uncertain, although ∼10 proteins so far have been localized in the costameres. To define the exact localization of costameres in human skeletal muscle fibers, we carried out an immunofluorescence study using confocal scanning laser microscopy on the fascia lata muscle of adult males.

A possible role of the plasmalemmal cytoskeleton, nitric oxide synthase, and innervation in infantile hypertrophic pyloric stenosis. A confocal laser scanning microscopic study.

Abstract In reference to a possible neuropathy in the pathogenesis of infantile hypertrophic pyloric stenosis (IHPS), previous studies have described alterations in peptidergic transmission while others have recently attributed an important role to nitrinergic activity. Little attention has been given to the organization of the extracellular matrix (ECM) and the constituent cytoskeleton and subsarcolemma of the pyloric smooth-muscle cell. To study a possible relationship between neuronal and muscular elements in IHPS, 9 biopsies from patients with IHPS and 5 biopsies of normal pylorus were examined using immunohistochemical techniques with regard to the distribution of nerve cells and fibers (bNOS and PGP 9.5) and the ECM (laminin) and cytoskeleton (talin, vinculin, dystrophin, α-smooth iso-actin, desmin) components of the pyloric muscle. Our results showed anti-protein gene product 9.5 and b-nitric oxide synthase immunoreaction respectively reduced or absent in nerve fibers with a positive reaction inside the ganglion cells. An uneven distribution of the ECM component laminin was evident, together with a negative immunoreaction to talin and dystrophin. The imunolocalization of vinculin, α-smooth iso-actin, and desmin was similar to the controls. Our findings suggest that there is a close relationship between the nerve and muscle elements in the pathophysiology of IHPS and that non-alteration of some elements of cytoskeleton organization can play an important role in regaining pyloric function after pyloromyotomy.

Changes in the distribution of actin-associated proteins in psoriatic keratinocytes. Immunohistochemical study using confocal laser scanning microscopy

Recent studies support the presence of adherens junctions at the dermal–epidermal interface in addition to hemidesmosomes. In this area the integrin/actin-containing cytoskeleton connection occurs by means of a complex of proteins called actin-associated proteins (talin, vinculin, α-actinin). As previous studies have demonstrated the presence in psoriatic lesions of marked alterations in both the basement membrane molecular composition and the polarized expression of integrins, we decided to determine whether alterations in the behaviour of the actin-associated proteins could be demonstrated. We thus undertook an immunolocalization study with monoclonal antibodies directed against talin, vinculin, and α-actinin in cutaneous biopsies taken from involved and uninvolved skin of 12 patients with extensive chronic plaque psoriasis. The findings showed an almost total lack of reaction against talin and vinculin in the basal layer and an increased positivity against the proteins in the suprabasal layers. Similar, though less marked, alterations were present in uninvolved psoriatic skin. These results, in agreement with those of previous studies, confirm serious alterations in the matrix protein/cytoskeleton connection system, and support the hypothesis that this condition may play a key role in the pathogenesis of the disease.

The dermoepidermal junction in psoriatic skin as revealed by scanning electron microscopy.

Abstract Our previous ultrastructural and immunohistochemical studies, in vivo and in vitro, have shown important modifications of the basement membrane of psoriatic skin, which could play a key role in the alterations of keratinocyte adhesion, migration, proliferation and differentiation. In order to complete the morphological examination of all the structures in the dermoepidermal junction of psoriatic skin, we carried out a scanning electron microscopic study using biopsies taken from eight psoriatic patients. The biopsies were fixed in a mixture of 0.2% paraformaldehyde and 0.25% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.4. The specimens were then frozen in liquid nitrogen and fractured following the natural cleavage planes and observed under a Jeol JSM-6301F field emission scanning electron microscope operating at 1.8–2.0 kV. The basal keratinocytes observed showed pore-like depressions on the lateral plasmalemma and villous-like projections in very dilated intercellular spaces. Moreover the basal cell plasma membrane was seen to rest on the papillary dermis without interposition of the lamina densa. The detachment of some keratinocytes enabled the examination of the lamina densa, which appeared slightly granular with numerous focal interruptions through which it was possible to observe the underlying collagen fibres. These findings, together with previously reported findings, support the hypothesis that in psoriasis molecular and structural alterations of the dermoepidermal junction are present, that could fundamentally alter the regulation of the cytomorphological processes and the normal functions of the basement membrane.