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Biomedical subjects

M Landau

Publications and source records attributed to M Landau.

At least 37 records · Page 2Linked to original sources
PubMed2000

Plantar hidradenitis in children induced by exposure to wet footwear.

Painful erythematous papules and nodules involving either the palms of the hands, or, more commonly, the soles of the feet, characterize palmoplantar eccrine hidradenitis or palmoplantar hidradenitis (PH). The younger pediatric population is predominately affected. Histologically, the eccrine gland apparatus is the target of inflammatory neutrophilic infiltrates. This entity has been reported under a variety of names, including traumatic plantar urticaria, neutrophilic eccrine hidradenitis, plantar erythema nodosum, and idiopathic recurrent palmoplantar hidradenitis. All are essentially the same process, described in different forms. Despite the growing number of reported cases, the pathogenesis remains obscure. We present four children with PH of the soles of the feet, who shared a common recent history of exposure to cold, damp, footwear. The temporal relationship between exposure to dampness and cold and the appearance of the skin lesions suggest a possible pathogenetic mechanism.

Child↗
PubMed2000

[Dermatitis from contact with Agave americana].

Various plants induce dermatitis in man. There have been only a few published cases of contact dermatitis caused by Agave americana (AA). We report intentional exposure to AA in a soldier seeking sick leave, and review our previously reported cases. Treatment with oral antihistamines and topical saline compresses resulted in subsidence of the systemic symptoms within 24 h and regression of cutaneous manifestations in 7-10 days. Physicians should be alert to the possibility of self-inflicted contact dermatitis induced by exposure to plants, especially to A. americana. Systemic signs may accompany the cutaneous lesions.

Adult↗
PubMed1999

Effects of psychotropic drugs on cell proliferation and differentiation.

Some of the psychotropic agents widely used for the amelioration of anxiety, depression, and psychosis also show an effect at the cellular proliferation level. Surprisingly little research, however, has been directed to the antitumoral potential of these drugs, alone or in combination with established cancer treatments. Our review of the literature to date has yielded some promising early findings. Ligands active at the benzodiazepine (BZ) receptors have been studied the most extensively and were found to have differential, concentration-dependent effects on the growth and proliferation of both normal and cancer cells. Of the phenothiazines tested, chlorpromazine (CPZ) and perphenazine (PPZ) had the most potent cytotoxic action on fibroblasts and glioma cells. Antiproliferative effects also were noted by these and other agents in leukemic and breast cancer cell lines. Additional psychotropic drugs studied include the atypical antipsychotics, antidepressants, and mood stabilizers, especially lithium. Most of the reported activities were observed in in vitro studies and were achieved at high pharmacological concentrations. Further in vivo studies in well-designed animal models are warranted to determine whether these well-tolerated, relatively inexpensive, and widely available drugs or their derivatives may be added in the future to the armamentarium of cancer pharmacotherapy.

Anticonvulsants↗
PubMed1999

The diagnostic value of café-au-lait macules.

Single café-au-lait macules (CALMs) are common in the pediatric population and in most children represent a normal finding. It is important to recognize whether the presence of multiple CALMs in a particular patient is normal or indicates an association with a multisystem disorder. This article addresses issues concerning the prevalence, genetics, and natural history of CALMs in the general population and reviews disorders in which CALMs are present as a characteristic trait.

Cafe-au-Lait Spots↗
PubMed1999

Unusual eruption as a presenting symptom of cat scratch disease.

Cat scratch disease (CSD) is a common infectious cause of subacute regional lymphadenopathy. Bartonella henselae is the principal etiologic agent. About 10% of CSD patients experience atypical manifestations, including rashes. The most common cutaneous manifestation of CSD is a papule at the inoculation site. We report a case of CSD presenting with an eruption on the upper trunk, reminiscent of Sweet's syndrome, accompanied by lymphadenopathy, arthralgia, and fever. Response to systemic corticosteroids was remarkable. Histopathologic findings refuted the diagnosis of Sweet's syndrome. Identification of anti-B henselae antibodies and B henselae DNA in the affected lymph node confirmed the diagnosis of CSD. This is a first report of extensive papuloedematous eruption as a cutaneous manifestation of CSD. Accurate diagnosis is possible due to the availability of serological tests and DNA amplification techniques.

Adult↗
PubMed1999

Computerized system to enhance the clinical diagnosis of pigmented cutaneous malignancies.

BACKGROUND: An increase in the incidence of cutaneous malignant melanoma in recent years has not been accompanied by satisfactory progress in diagnostic methods. This study was carried out to evaluate a specially designed computerized image analysis system, called Derma Vision, to aid in the differentiation between malignant and benign cutaneous pigmented lesions. METHODS: Seventy-one lesions were photographed with a digital camera and the data were analyzed by the Derma Vision system. The system assessed the variation of hues in each image, calculated the mean standard deviation of the hues, and produced a value that expressed the range of hues in the lesion. The lesions were then excised and examined histologically. The computer-assisted clinical diagnosis was correlated with the histologic diagnosis to determine the accuracy of the former. RESULTS: Derma Vision predicted the malignant character of a lesion with 92% precision, compared with 87% accuracy based only on the clinical features. CONCLUSIONS: This simple, inexpensive device can boost the accuracy of clinical diagnosis and provide a useful tool to the physician faced increasingly with having to determine whether pigmented lesions are malignant or benign.

Basal Cell Carcinoma↗
PubMed1998

Antiproliferative and differentiating effects of benzodiazepine receptor ligands on B16 melanoma cells.

In this study, we evaluated the effect of several ligands active at the central-type and peripheral-type benzodiazepine receptor (BzR) (clonazepam, diazepam, PK11195 and Ro5-4864) on the growth and differentiation of B16 melanoma cells. All tested BzR ligands were able to suppress proliferation of the cells at the micromolar range and in a concentration-dependent manner. However, agents selectively active at the peripheral-type BzR (PK11195 and Ro5-4864) exhibited more potent antiproliferative activity. In addition, the BzR ligands were demonstrated to affect the cell cycle by reducing the percent of cells in the S phase and increasing the percent in the G2/M phase. BzR ligands induced cellular phenotypic alterations, which have been previously shown to be associated with melanoma cell differentiation. These alterations included: marked morphological changes, enhancement of melanogenesis, lipid accumulation and increase in the activity of gamma glutamyl transpeptidase. All BzR ligands induced a marked reduction in the concentration of UTP and most of them did the same in GTP and CTP, while ATP levels were not significantly altered. In summary, BzR ligands (clonazepam, diazepam, PK11195 and Ro5-4864) were found to exert antitumor effects in B16 melanoma cells. These findings encourage further studies of a possible therapeutic potential of BzR ligands in treatment of melanoma.

Animals↗
PubMed1998

Substituted 4-acylpyrazoles and 4-acylpyrazolones: synthesis and multidrug resistance-modulating activity.

A series of 4-acyl-3-pyrazolone derivatives with a 3-substituted 2-hydroxy-3-aminopropyl chain attached to pyrazole N-1 (7-20) as well as isomeric 4-acyl-5-(3-substituted 3-amino-2-hydroxypropoxy)pyrazole derivatives (5, 6) were synthesized, and their multidrug resistance (MDR)-modulating activity was measured using the daunomycin efflux assay. Reaction of N1-substituted 4-acyl-3-pyrazolones (tautomer to 4-acyl-5-hydroxypyrazoles) with excessive epichlorohydrin and successive treatment with an appropriate amine resulted in N-alkylation and thus afforded the target pyrazolone derivatives 7-20. In contrast, O-alkylation occurred upon reaction with 1 equiv of epichlorohydrin and subsequent treatment with amine leading to the corresponding 4-acyl-5-pyrazolyl ethers 5 and 6. QSAR studies showed a good correlation of MDR-modulating activity with lipophilicity of the compounds. Inclusion of hydrogen bond acceptor strength and steric parameters as descriptors led to a QSAR equation with remarkably increased predictive power (r2cv = 0.92). Additionally, ortho substitution of the propanolamine side chain and the acyl moiety is favorable. Detailed NMR spectroscopic investigations were carried out with the title compounds.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Contact dermatitis with systemic symptoms from Agave americana.

BACKGROUND: Twelve cases of contact dermatitis provoked by Agave americana are described, 10 with systemic signs and symptoms and 8 with abnormal laboratory results. RESULTS: Patient history revealed a background of intentional exposure among soldiers seeking sick leave. Treatment with oral antihistamines and topical saline compresses resulted in subsidence of the systemic symptoms within 24 h of hospitalization and regression of cutaneous manifestations in 7-10 days. CONCLUSION: The importance that dermatologists be alert to the possibility of self-inflicted contact dermatitis induced by exposure to plants is stressed, especially to A. americana. Systemic signs are not rare accompanying findings with this plant.

Adolescent↗
PubMed1998

Screening for tumour suppressor p16(CDKN2A) germline mutations in Israeli melanoma families.

Approximately ten percent of patients with malignant melanoma have family histories of the disease, suggesting a genetic predisposition. Germline mutations in tumour suppressor p16 gene have been implicated as disease causing mutations in some of the melanoma families. The frequency of families with p16 germline mutations among melanoma prone families varies from eight to fifty percent. The range of the variability is influenced apparently by the number of melanoma affected individuals within the family, as well as by other, yet unidentified factors. Ethnic background is known to determine both the frequency and the nature of germline alterations. Recently, specific mutations in tumour suppressor genes involved in breast cancer and in colon cancer were found at elevated frequency among Ashkenazi Jews. This report describes results of a screening for p16 germline alterations in a collection of Israeli melanoma families. We have analyzed genomic DNA from thirty one Ashkenazi and non-Ashkenazi Jewish melanoma families, as well as from thirty melanoma patients without an apparent family history of the disease. The entire coding region of the p16 gene was screened by single strand conformation polymorphism analysis and direct DNA sequencing. We have detected a number of carriers with the Ala148 Thr polymorphism at the end of the second exon and several instances of 500(G=>C) substitution at the 3' untranslated portion of the gene.

Female↗
PubMed1997

Conduction block and chaotic dynamics in an asymmetrical model of coupled cardiac cells.

The initiation and propagation of the cardiac impulse depends on intrinsic properties of cells, geometrical arrangements, and intercellular coupling resistances. To address the issue of the interplay between these factors in a simple way, we have used a system, based on the van Capelle and Dürrer model, including a pacemaker and a non-pacemaker cell linked by an ohmic coupling resistance. The influence of asymmetrical cell sizes and electronic load was investigated by using numerical simulations and continuation-bifurcation techniques. The loading of a small pacemaker cell by a large non-pacemaker one (pacemaker: non-pacemaker size ratio = 0.3) was expressed as a pronounced early repolarization in the pacemaker cell and a quite long latency for the impulse propagation. Using coupling resistance as the continuation parameter, three behavioral zones were detected from low to high coupling resistance values: a zone of total quiescence (0:0), a zone of effective entertainment (1:1), and a zone of total block (1:0 pattern). At the boundary between 1:1 and 1:0 patterns, for relatively high coupling resistance values, a cascade of period doubling bifurcations emerged, corresponding to discrete changes of propagation patterns leading into irregular dynamics. Another route to irregular dynamics was also observed in the parameter space. The high sensitivity of the detected irregular dynamics to initial conditions and the positive value of the maximum Lyapunov exponent allowed us to identify these dynamics as being chaotic. Since neither intermediate block patterns nor irregular dynamics were observed with larger size ratios, we suggest that the interplay between resting membrane conductance of the non-pacemaker cell and intercellular coupling may bring about these rhythmic disturbances.

Animals↗
PubMed1997

Histopathologic findings in drug-induced pemphigus.

Drug-induced pemphigus represents a diagnostic challenge, as usually no clinical feature differentiates it from its idiopathic counterpart. It was suggested recently that some histologic features may assist in diagnosing drug-associated diseases. The purpose of the study was to determine whether the histologic criteria suggested in the literature are specific enough to arouse suspicion of drug-induced pemphigus. Biopsy specimens of drug-induced and idiopathic pemphigus were reviewed by five dermatologists with no clinical data available about the patients. The sections were assessed to the presence of spongiosis with eosinophils, vacuolar degeneration, and the degree of acantholysis and cleavage level. Using the suggested criteria, the reviewers were unable to confirm a diagnosis of drug-induced pemphigus. It is advisable to consider drug etiology in every case of newly diagnosed pemphigus based on clinical criteria an detailed drug consumption history, as histologic features do not differentiate between drug-associated and idiopathic disease.

Acantholysis↗
PubMed1996

Topical treatment with 1% sodium cromoglycate in pyoderma gangrenosum.

BACKGROUND: Pyoderma gangrenosum is an uncommon skin disease usually treated with systemic drugs, most frequently corticosteroids. Isolated topical treatment is usually considered unsatisfactory. OBJECTIVE: To evaluate the effect of topical 1% sodium cromoglycate solution on pyoderma gangrenosum in 5 patients 25-30 years of age. METHODS: 5 patients, including 2 under systemic steroid treatment, hospitalized in our department from 1992 to 1993 because of pyoderma gangrenosum, were treated with topical 1% sodium cromoglycate solution. Systemic corticosteroids were further added in 2 patients whose initial improvement was inadequate. RESULTS: Initial improvement was noted in all 5 patients after 3-7 days of sodium cromoglycate treatment. Complete healing of the ulcers occurred within 5-8 weeks. CONCLUSIONS: Topical treatment with sodium cromoglycate can be effective as adjunctive or sole treatment in pyoderma gangrenosum.

Administration, Topical↗