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Biomedical subjects

G Rabbiosi

Publications and source records attributed to G Rabbiosi.

At least 19 recordsLinked to original sources
PubMed1992

The role of the intercellular matrix in dermal calcinosis of the CRST syndrome. An electron-microscopic study.

We performed an electron-microscopic study on calcium deposits in two patients with calcifying scleroderma (CRST syndrome). Calcium deposits were detected both intracellularly in the mitochondria of phagocytic cells and extracellularly. Needle-like crystals measuring up to 4,500 A in length and approximately 60 A in width were present in both the Von Kossa-positive regions and the apparently normal dermal areas around the calcification sites. Although the fibrillar matrix's ultrastructure was normal, hollow oxytalan fibrils were detected. Slightly electron-opaque, star-shaped material was observed among the fibrillar component of the matrix (matrix granules), which is the ultrastructural expression of some types of proteoglycans containing keratan sulphate and chondroitin sulphate. These granules cannot be detected in normal dermis. The extrafibrillary calcium deposits on these mucopolysaccharide structures may represent an early event in the complex pathogenesis of calcification in the CRST syndrome.

Actin Cytoskeleton↗
PubMed1992

Bullous lesions in acrodermatitis enteropathica. Histopathologic findings regarding two patients.

Acrodermatitis enteropathica (AE) is an autosomic recessive disorder affecting early infancy. Two cases of infantile AE with low plasma zinc levels are reported in which unusually prominent bullous and vesicobullous lesions were seen on the hands and feet, in addition to the more typical erythematous and scaly patches. Both psoriasiform and bullous lesions responded dramatically to oral zinc-sulfate supplementation. The histopathologic features of the bullous lesions of AE have not previously been fully examined. Histologically, the bullous lesions were characterized by intraepidermal vacuolar changes with massive ballooning, leading to intraepidermal vesiculation and blistering, with prominent epidermal necrosis and with no acantholysis. The bullous lesions did not arise on erythematous patchy lesions, but developed ex novo on unaffected skin. The histopathologic differential diagnosis with other bullous conditions is discussed.

Acrodermatitis↗
PubMed1992

Evidence for CD8+ cell increase in long-term PUVA-treated psoriatic patients after PUVA discontinuation.

Long-term PUVA-treated psoriatic patients given maintenance therapy (UVA doses greater than 1,000 J/cm2) have been demonstrated to undergo lymphopenia and a decrease in the total number of circulating CD3+ and CD4+ T cells. The aim of this study was to assess whether the impairment of T cells is detectable also in psoriatic patients after long-lasting PUVA discontinuation. A group of 34 psoriatic patients (25 males, 9 females; mean age 52.7 +/- 12.82 years), who had previously been treated by PUVA therapy (average cumulative dose 1,898.48 +/- 1,207.12 J/cm2), was studied 1 year or more after discontinuation of PUVA therapy. The patients studied failed to show any impairment in CD3+ and CD4+ cells. Nevertheless, a significant increase (p less than 0.05) in circulating CD8+ cells (both in the percentage and the total number) was detectable in PUVA patients as compared to appropriate controls. The significance and implications of this finding are not known and need further investigations.

CD4-CD8 Ratio↗
PubMed1992

Objective prick test evaluation: non-invasive techniques.

Prick test reactions are evaluated and quantified, comparing visual assessment with two non-invasive techniques: remittance spectroscopy and pulsed ultrasound for erythema and skin thickness measurements. Different information is provided by the two methods. Remittance spectroscopy discriminates well between negative and positive reactions (+ or ++), while failing to differentiate stronger reactions, where edema is a prominent feature. The latter reactions are better evaluated by skin thickness measurements, which, on the contrary, are less sensitive in revealing small skin thickness increases in weak reactions.

Adult↗
PubMed1991

Age of onset in vitiligo: relationship with HLA supratypes.

HLA class I (A, B, C), class II (DR, DQ) histoglobulins and HLA class III (C4A, C4B and Bf) complement factors were analysed in 87 patients with vitiligo and in controls. Two HLA supratypes seem to mark different age of onset of vitiligo: HLA-BfS, C4A3, C4B1, DR5 (W11), DQW3 is characteristic of the pediatric form; while HLA-BfS, C4A3, C4B1, DR7, DQW2 marks the adult form of disease. The importance of defining HLA supratype, not single alleles, is discussed.

Adolescent↗
PubMed1991

In vivo transcutaneous penetration of nicotinates and sensitive skin.

Proclivity to develop irritant reactions and transcutaneous penetration of nicotinates has been investigated in 20 subjects of both sexes, divided into reactors and nonreactors on the basis of the responses to irritant stimuli. 1% sodium lauryl sulphate (patch application for 24 h) and 5% lactic acid in aqueous solutions were used to detect chemical and sensory (subjective) irritation. The vasodilatation induced was measured using a chromameter for 1 h after topical application of the chemical. The area-under-the-curve response and the peak response was used to assess the in vivo penetration of methyl nicotinate (10 mM in aqueous solution). Significant differences were found between reactors and non-reactors. Non-reactors showed a significantly decreased area-under-the-curve response and peak response to methyl nicotinate compared to reactors. Nicotinate-induced vasodilatation has been used as a model to study transcutaneous penetration of chemicals; the correlation between increased penetration of nicotinates and skin hyperreactivity to irritant substances may suggest an increased transcutaneous penetration of water-soluble chemicals in individuals with sensitive skin.

Administration, Cutaneous↗
PubMed1991

Lymphopenia and decrease in the total number of circulating CD3+ and CD4+ T cells during 'long-term' PUVA treatment for psoriasis.

The relationship between high-dose PUVA treatment in psoriatic patients and peripheral T lymphocyte subsets (total number and percentage) has been studied. Of the two groups of patients considered, the first included 19 patients, all affected by chronic, progressively worsening psoriasis; they had never been previously treated by photochemotherapy. The second group included 13 psoriatic patients, who had received an average cumulative dose of 2,007.69 +/- 1,191.05 J/cm2. The 'long-term' PUVA-treated group was assessed while undergoing maintenance therapy. No significant differences were found between untreated patients and healthy controls for any of the parameters considered. A significant reduction (p less than 0.05) in the total number of lymphocytes in long-term PUVA-treated patients both versus untreated patients and controls was found. Furthermore, long-term PUVA-treated patients showed a significant reduction (p less than 0.05) in the percentage of lymphocytes as compared with controls. The reduction in the total number of CD3+ and CD4+ T cells was, moreover, significant (p less than 0.05) as compared with untreated patients. The impairment of circulating CD3+ and CD4+ T cells (total number) was only on the borderline of statistical significance vis-à-vis controls. These findings suggest the usefulness of a careful assessment of circulating T lymphocyte subsets in patients who undergo long-term PUVA therapy.

Adult↗
PubMed1991

Skin bioengineering in the noninvasive assessment of cutaneous aging.

Cutaneous changes induced by aging can be quantified and monitored noninvasively by means of bioengineering tools. Skin elasticity, hydration, skin blood flow and skin surface pattern show age-related changes reflecting the damage of cutaneous structures involved. Impairment and degeneration of elastic and collagen networks are responsible for the progressive decrease in skin elasticity recorded during aging. Reduction in blood flow and water supply with probably defective stratum corneum binding result in reduced stratum corneum water content and transepidermal water loss. Morphological changes such as increased skin roughness, pigmentation and alteration of skin surface pattern appearing from the age of 30 years onwards may be investigated at a subclinical level allowing the detection of early signs of aging.

Biomechanical Phenomena↗
PubMed1990

Flagellate dermatitis after bleomycin. A histological and immunohistochemical study.

A case of flagellate dermatitis after administration of bleomycin is reported in a patient with Hodgkin's disease. Histopathological and immunohistochemical analysis revealed a drug-induced skin toxic reaction rather than a lymphomatous infiltrate. Pigmentary changes observed after the early erythematous eruption were due to a postinflammatory effect.

Adult↗
PubMed1990

In vivo tretinoin-induced changes in skin mechanical properties.

Topical tretinoin has been reported as having anti-aging effects on photodamaged skin. The purpose of this study was to evaluate tretinoin-induced changes in the mechanical properties of the skin of 18 patients (aged 39 +/- 8 years) after 4 months of treatment with topical 0.05% tretinoin on one forearm and a placebo base cream on the other. The biomechanical skin parameters investigated were elasticity, extensibility and hysteresis and data were normalized for skin thickness. A slight but non-significant increase of skin elasticity was detected in the tretinoin-treated sites using low-stressing forces (1.2 X 10(4) Nm-2) and at higher loads (3.8 X 10(4) Nm-2), the increase in skin elasticity was significant (P less than 0.01). This improved skin elasticity was dependent on the increased collagen resulting from topical tretinoin and the replacement of elastotic material. However, topical tretinoin treatment did not improve the responses mediated by elastic fibres.

Adult↗
PubMed1990

Ranking of surfactant skin irritancy in vivo in man using the plastic occlusion stress test (POST).

Irritant effects and disturbance of water-holding capacity induced by surfactants were investigated using the plastic occlusion stress test (POST) technique. 4 surfactants (sodium lauryl sulphate (SLS), sorbitan monolaurate, cocoamidopropyl betaine and benzalkonium chloride) and an amphoteric/nonionic (A/N) mix were investigated. 1 x daily for 3 days, test surfactants were applied to marked sites (open) on the volar forearm. After 24 h occlusion with a plastic chamber on the 4th day, skin surface water loss (SSWL) (g/m2h) was recorded continuously for 25 min with an evaporimeter. The differences between the surfactants were statistically significant (Friedman's test p less than 0.01). SLS and the A/N mix revealed significant differences compared to the other compounds (p less than 0.05), both in decay constants and in values recorded at the beginning and at the end of the decay curve. The study suggests a mechanism for the high irritant potential of sodium lauryl sulphate compared to other surfactants: sorbitan monolaurate and benzalkonium chloride seem to influence (at the concentrations tested) to a lesser extent the water-holding capacity of the stratum corneum. The clinical and biological relevance of these observations requires long-term clinical correlations with final product use tests.

Adult↗
PubMed1990

Relapsing eruptive psoriasis and immunological changes triggered by growth hormone therapy in a growth hormone-deficient girl.

A 9.8-year-old girl with growth hormone (GH) deficiency and concomitant chronic and localized psoriasis of the groins and axillae showed repeated and sudden relapse of eruptive psoriasis after GH treatment. The aggravating effect of GH and the improvement of the skin condition after withdrawal suggests, at least in this case, that GH plays a significant role in the pathogenesis of psoriasis.

Child↗
PubMed1990

Alopecia areata: more on topical sensitizers.

Our experience on treating alopecia areata with topical sensitizers (diphencyprone, squaric acid dibutylester) is reported: staging, prognosis, side effects, follow-up, and psychological attitude of the patients towards this therapy and wigs are the focused aspects. The possible mechanisms of action of these allergens are discussed, reporting the case of a female patient with concomitant appearance of hair regrowth and psoriatic plaques in the same area after SADBE therapy.

Administration, Topical↗
PubMed1990

In vivo hydration and water-retention capacity of stratum corneum in clinically uninvolved skin in atopic and psoriatic patients.

Hydration and the water-retention capacity of stratum corneum have been investigated in uninvolved psoriatic and atopic skin and compared with that of healthy controls. Thirty-three subjects of either sex and matched for age entered the study. The subjects were free from all signs of skin disease and skin dryness. Hydration was evaluated by means of transepidermal water loss and skin capacitance measurements. Water-retention capacity was investigated using the plastic occlusion stress test. Atopic skin differed significantly from uninvolved psoriatic and control skin which had a reduced water content and an increased transepidermal water loss. Furthermore, the skin surface water loss profile representing the stratum corneum water-retention capacity was significantly lower in normal atopic skin. The data suggest that clinically normal skin may be functionally abnormal, resulting in a defective barrier that could lead to higher risk of irritant or contact dermatitis.

Adult↗
PubMed1990

[Amiodarone-induced pigmentation. A histological, ultrastructural study and review of the literature].

Amiodarone is an iodinated cardiac antiarrhythmic drug that causes a slate- gray discoloration of sun-exposed skin. Histopathologically, biopsy specimens of two patients affected by amiodarone pigmentations reveal yellow-brown granules in the reticular dermis, both in the cytoplasm of macrophages and between the collagen bundles. The histochemical stainings of the granules suggest that a lipofuscin pigment rather than melanin is present in the granules. Electron microscopy displays distinctive intracytoplasmic inclusions in many dermal cell types. Six morphologic types can be seen: 1) electron-lucent, membrane bound granules, 2) granules with electron dense nucleus, 3) lamellar "myelin-like" granules, 4) granules with a combination of electron-dense and electron-lucent areas, 5) electron-dense membrane-bound granules, 6) electron-dense no-membrane granules. The different dimensions, structure and shape are related to the structural and aggregational phases of the granules. In particular their pathogenesis may be related to the action of the drug on cell membranes with thesaurismosis, local metabolic damage, accumulation of the drug in the lysosomes and acceleration of the physiological ageing cell process.

Aged↗
PubMed1990

[A clinical study on the use of norfloxacin in the therapy of urethritis caused by Chlamydia trachomatis].

Norfloxacin (NOR) was given to 37 patients affected by urethritis due to Chlamydia trachomatis (CT), as demonstrated by clinical findings and fluorescent monoclonal antibody in urethral swab. The patients were divided into two groups according to a randomization list, and given either: NOR 400 mg t.i.d. or NOR 800 mg b.i.d. for 10 days. The 2 groups were comparable in terms of age, clinical presentation and duration of symptoms. Six out of 18 patients treated by regimen 2 had persistence of CT at the end of treatment (2 cases were clinically improved), while 4 out of 19 patients in group 1 dit not respond to the treatment. Overall 12 patients in group 2 (66.6%) and 15 patients in group 1 (79%) were asymptomatic and negative for fluorescent antibody at the end of the treatment. Both regimens were well tolerated. Our data show that NOR given at dosage higher than those usually recommended (e.g. 400 mg b.i.d.), may be of value for the treatment of urethritis due to Chlamydia trachomatis.

Adolescent↗
PubMed1990

[Immunohistochemical study of neoplasms of the sweat glands].

The paper reports a study of 34 sweat gland tumours, 3 of which were malignant. In line with recent publications on the topic, no immunophenotype is identified which could differentiate between pathologies of an eccrine as opposed to apocrine origin. With regard to the possibility of distinguishing malignant from benign tumours, the paper reconfirms the importance of CEA which is the only immunomarker common to all the malignant forms examined.

Biomarkers, Tumor↗