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P Stavropoulos

Publications and source records attributed to P Stavropoulos.

18 recordsLinked to original sources
PubMed2006

Assessment of the efficacy of cryosurgery in the treatment of granuloma faciale.

BACKGROUND: Granuloma faciale (GF) is an uncommon dermatosis of unknown pathogenesis. Multiple treatments have been proposed with varying results. We report nine cases treated successfully with cryosurgery and we review the literature. OBJECTIVES: To study the efficacy, tolerability and safety of cryosurgery techniques in the treatment of GF. METHODS: Nine immunocompetent adults with GF were treated by cryosurgery. The initiation of the therapy was preceded by a 60-day washout period in all subjects using other medication. Two different techniques were used (open-spray and contact cryo-probe). RESULTS: All patients were treated successfully. Apart from mild postinflammatory hypopigmentation in two patients that resolved within 4 months, no other adverse event was mentioned. During an average 24-month follow-up period after the integration of therapy, no recurrences were observed. CONCLUSIONS: Cryosurgery is an efficient, safe, inexpensive, easily used method for this uncommon dermatosis, which can be proposed as a treatment of first intention.

Adult↗
PubMed2001

Induction of beta-transducin repeat-containing protein by JNK signaling and its role in the activation of NF-kappaB.

Activation of Jun N-kinase (JNK) and NF-kappaB transcription factor are the hallmarks of cellular response to stress. Phosphorylation of NF-kappaB inhibitor (IkappaB) by respective stress-inducible kinases (IKK) is a key event in NF-kappaB activation. beta-TrCP F-box protein mediates ubiquitination of phosphorylated IkappaB via recruitment of SCF(beta-TrCP)-Roc1 E3 ubiquitin ligase complex. Subsequent proteasome-dependent degradation of IkappaB results in activation of the NF-kappaB pathway. We found that a variety of cellular stress stimuli induce an increase in the steady state levels of beta-TrCP mRNA and protein levels in human cells. Activation of stress-activated protein kinases JNK (and, to a lesser extent, p38) by forced expression of constitutively active mutants of JNKK2 and MKK6 (but not MEK1 or IKKbeta) also leads to accumulation of beta-TrCP. Transcription of the beta-TrCP gene is not required for JNK-mediated induction of beta-TrCP. A synergistic effect of stimulation of IKK and JNK on the transcriptional activity of NF-kappaB was observed. The mechanisms of beta-TrCP induction via stress and its role in NF-kappaB activation are discussed.

3T3 Cells↗
PubMed2001

The gif paradox.

This Account summarizes research work on the structural aspects and functional features encountered in all major branches of the Gif family of hydrocarbon-oxidizing reagents. Despite assertions by the inventor of Gif chemistry, D. H. R. Barton, to the effect that nonradical pathways could better explain the behavior of Gif systems, detailed experimental investigations provide compelling evidence to support the preponderance of oxygen- and carbon-centered radical chemistry.

Hydrocarbons↗
PubMed2001

Determinants of carotid plaque instability: echoicity versus heterogeneity.

OBJECTIVE: to identify the echoicity and heterogeneity of carotid plaques associated with ipsilateral symptomatic and asymptomatic neurovascular presentations. DESIGN: cross-sectional study. MATERIALS: a total of 113 patients, with 127 symptomatic and asymptomatic plaques, were studied. METHODS: the duplex images of the plaques were analysed echoically in a computer by means of Grey Scale Median (GSM) [hypoechoic (low GSM), hyperechoic (high GSM)]. The presence or absence of at least two plaque regions within the plaque area being echoically uniform (no variation of echoicity), occupying each at least 10% of the plaque area and having GSM difference greater than the plaque GSM was evaluated to distinguish the heterogeneous (presence of this pattern) from the homogeneous (absence of this pattern) plaques. RESULTS: the symptomatic status was associated with plaques of low median GSM (10.5) and 88% prevalence of the homogeneous pattern as contrasted with the asymptomatic status that was associated with high median GSM (28) and 65% prevalence of the homogeneous pattern [(p=0.001 (GSM), p=0.003 (heterogeneity)]. CONCLUSIONS: symptomatic plaques were associated with hypoechoic and predominant homogeneous echo-pattern whereas the asymptomatic ones were associated with hyperechoic and less predominant homogeneous pattern.

Aged↗
PubMed2000

Synthesis, characterization, and reactivity of ferrous and ferric oxo/peroxo pivalate complexes in relation to Gif-type oxygenation of substrates.

This study examines structural features and aspects of reactivity of Gif-type reagents, which depend on O2/Zn to mediate oxidation of hydrocarbons. The reagents investigated derive from the use of iron complexes with the anion of the weak carboxylic acid Me3CCO2H (pivalic acid (PivH)) in pyridine/PivH. In these solutions, the known compound [Fe3O(O2CCMe3)6(py)3] is reduced by Zn to generate yellow-green [FeII(O2CCMe3)2(py)4], which readily reverts to [Fe3O(O2CCMe3)6(py)3], and eventually to [Fe3O(O2CCMe3)6(py)3]+, upon exposure to dioxygen. All three species are equally well suited to mediate Gif-like oxygenation of substrates supported by O2/Zn. [FeIII3O(O2CCMe3)6(L)3]+ (L = H2O, py) is converted by H2O2 to afford the hexairon(III) peroxo compounds [Fe6(O2)(O)2(O2CCMe3)12(L)2] (L = Me3CCO2H, py), which feature a [Fe6(eta 2-mu 4-O2)(mu 3-O)2] core previously documented in the closely related [Fe6(O2)(O)2(O2CPh)12(H2O)2]. A similar peroxo species, [Fe6(O2)(O)2(O2CCMe3)2(O2CCF3)10(H2O)2], is obtained upon replacing all pivalate ligands by trifluoroacetate groups with the exception of those pivalates that bridge between the two [Fe3O(O2CCF3)5(H2O)]2+ units. The structure of the [Fe6(O2)(O)2] core in these peroxo species is found to range from a recliner to a butterfly-type conformation. Reduction of [Fe6(O2)(O)2(O2CCMe3)12(HO2CCMe3)2] with NaBH4 generates [Na2Fe4(O)2(O2CCMe3)10(L)(L')] (L = CH3CN, L' = Me2CO; L = L' = Me3CCO2H), which feature a [Na2Fe4(O)2] core possessing a bent butterfly conformation of the [Fe4(O)2] unit. Oxidation of the same peroxo complex by CeIV or NOBF4 regenerates the oxo-bridged [Fe3O(O2CCMe3)6(solv)3]+ (solv = EtOH, H2O, thf). Employment of the sterically encumbered 2-Me-5-Etpyridine provides the tetrairon compound [Fe4(O)2(O2CCMe3)8(2-Me-5-Etpy)2], which can be readily transformed upon treatment with H2O2 to the asymmetric peroxo complex [Fe6(O2)(O)2(O2CCMe3)12(2-Me-5-Etpy)2]. The peroxo-containing complexes oxidize both cis-stilbene and adamantane in either benzene or py/PivH, but only under forceful conditions and at very low yields. The low reactivity and high selectivity (tert/sec = 8) obtained in the oxidation of adamantane suggests that the present type of peroxo species is not directly involved in catalytic Gif-type oxygenations of adamantane.

Etilefrine↗
PubMed2000

Structural and functional characteristics of rhenium clusters derived from redox chemistry of the triangular [ReIII3(mu-Cl)3] core unit.

The present study investigates structural and functional aspects of the redox chemistry of rhenium(III) chloride [Re3Cl9] (1) in aqueous and organic solvents, with emphasis on the dioxygen-activating capabilities of reduced rhenium clusters bearing the Re3(8+) core. Dissolution of 1 in HCl (6 M) generates [Re3(mu-Cl)3Cl9]3- (2a), which can be isolated as the tetraphenylphosphonium salt (2b). Anaerobic one-electron reduction of 1 by Hg in HCl (6-12 M) produces [(C6H5)4P]2[Re3(mu-Cl)3Cl7(H2O)2].H2O (3), the structure of which features a planar [Re3(mu-Cl)3Cl3] framework (Re3(8+) core), involving two water ligands that occupy out-of-plane positions in a trans arrangement. Compound 3 dissociates in the presence of CO, yielding [(C6H5)4P]2[ReIII2Cl8] (4) and an unidentified red carbonyl species. In situ oxidation (O2) of the reduced Re3(8+)-containing cluster in HCl (6 M) produces quantitatively 2a, whereas oxidation of 3 in organic media results in the formation of [(C6H5)4P]4[(Re3(mu-Cl)3Cl7(mu-OH))2].2CH2Cl2 (5). The structure of 5 reveals that two oxygen ligands (hydroxo units) bridge asymmetrically two Re3(9+) triangular clusters. The origin of these hydroxo units derives from the aquo ligands, rather than O2, as shown by 18O2 labeling studies. The hydroxo bridges of 5 can be replaced by chlorides upon treatment with Me3SiCl to afford the analogous [(C6H5)4P]4[(Re3(mu-Cl)3Cl7(mu-Cl))2].10CH2Cl2 (6). The reaction of 5 with Hg in HCl (6 M)/tetrahydrofuran regenerates compound 3. Complexes 1-3 exhibit nitrile hydratase type activity, inducing hydrolysis of CH3CN to acetamide. The reaction of 3 with CH3CN yields [(C6H5)4P]2[Re3(mu-Cl)3Cl6.5(CH3CN)1.5(CH3C(O)NH)0.5] (7), the structure of which is composed of [Re3(mu-Cl)3Cl7(CH3CN)2]2- (7a) and [Re3(mu-Cl)3Cl6(CH3CN)(CH3C(O)NH)]2- (7b) (Re3(8+) cores) as a disordered mixture (1:1). Oxidation of 7 with O2 in CH3CN affords [(C6H5)4P]2[Re3(mu-Cl)3Cl7(CH3C(O)NH)].CH3CN (8) and small amounts of [(C6H5)4P][ReO4] (9). Compound 8 is also independently isolated from the reaction of 2b with wet CH3CN, or by dissolving 5 in CH3CN. In MeOH, 5 dissociates to afford [(C6H5)4P]2[Re3(mu-Cl)3Cl8(MeOH)].MeOH (10).

Journal Article↗
PubMed1999

FBI-1, a factor that binds to the HIV-1 inducer of short transcripts (IST), is a POZ domain protein.

The HIV-1 promoter directs the synthesis of two classes of transcripts, short, non-polyadenylated transcripts and full-length, polyadenylated transcripts. The synthesis of short transcripts is activated by a bipartite DNA element, the inducer of short transcripts or IST, located downstream of the HIV-1 transcriptional start site, while the synthesis of full-length transcripts is activated by the viral activator Tat. Tat binds to the RNA element TAR, which is encoded largely between the two IST half-elements. Upon activation by Tat, the synthesis of short RNAs is repressed. We have previously purified a factor called FBI-1 (for factor that binds to IST) whose binding to wild-type and mutated ISTs correlated well with the abilities of these ISTs to direct the synthesis of short transcripts. Here, we report the cloning of cDNAs encoding FBI-1. FBI-1 contains a POZ domain at its N-terminus and four Krüppel-type zinc fingers at its C-terminus. The C-terminus is sufficient for specific binding, and FBI-1 can form homomers through its POZ domain and, in vivo, through its zinc finger domain as well. In addition, FBI-1 associates with Tat, suggesting that repression of the short transcripts by Tat may be mediated through interactions between the two factors.

Amino Acid Sequence↗
PubMed1999

Acne neonatorum: a study of 22 cases.

BACKGROUND: Acne is not uncommon in the neonatal period. Acne neonatorum is characterized by a mainly facial eruption of inflammatory and noninflammatory lesions. It is most commonly mild and transient. Hyperactivity of sebaceous glands, stimulated by neonatal androgens, has been implicated as the underlying pathogenetic mechanism. MATERIALS AND METHODS: All patients diagnosed with acne neonatorum in "A. Sygros" Hospital, Athens, Greece, during the years 1993-1996, were evaluated clinically and epidemiologically. Histologic examination and smears for Propionibacterium acnes and Pityrosporum ovale were performed in selected cases. RESULTS: Of the 22 patients studied, 18 were male (81.8%) and 4 were female. The mean age at onset was 3 weeks and the mean duration of the disease was 4 months. Papules and pustules were the most frequent types of lesions (72.7%), followed by comedones only (22.7%). The cheeks were the most common site of predilection (81.8%). A family history of acne was reported in only three patients. Histologic examination showed hyperplastic sebaceous glands with keratin-plugged orifices. Smears for P. ovale were negative. CONCLUSIONS: Our findings are consistent with previous experience, although inflammatory lesions were encountered more often than previously reported. Hereditary factors did not seem to play a significant role in our series. Topical treatment hastened the resolution of this self-limited condition. Recalcitrant cases warrant investigation for underlying androgen excess.

Acne Vulgaris↗
PubMed1997

Cognitive function in non-demented individuals complaining of short-term memory disturbances: a study with event-related potentials (P 300) and brain CT scan.

Event-related potentials (ERPs) were elicited in 30, non-consecutive, non-demented individuals, complaining of short-term memory disturbances. Fifteen of them had a moderate diffuse cerebral atrophy on their brain CT and the other 15 had a negative brain CT. ERPs were also elicited in 15 age-matched controls with no reported memory disturbances and negative brain CTs. The statistical analysis showed that the group of individuals with cerebral atrophy had a significantly prolonged P300 (P3) latency and a decreased P3 amplitude compared to controls. It is concluded that among persons complaining of short-term memory disturbances, the individuals who show cerebral atrophy, taken as a group, have a P3 latency prolongation and/or low P3 amplitude a finding which reflects an impaired information processing.

Adult↗
PubMed1996

Hereditary neuropathy with liability to pressure palsies: the same molecular defect can result in diverse clinical presentation.

Hereditary neuropathy with liability to pressure palsies (HNPP) is a peripheral nerve disorder characterized by autosomal dominant inheritance, recurrent pressure palsies, reduced motor and sensory conduction velocities and sausage-like swellings (tomacula) of myelin sheaths in nerve biopsy. Two young adult patients are reported as index cases of two families in which HNPP was diagnosed. The first patient presented with recurrent pressure palsies, whereas the second suffered from fasciculations and myokymias in his right hand, with difficulty in writing, and upper and lower limb paraesthesias of 3 years' duration. Electrodiagnostic studies revealed slowing of conduction primarily in common sites of compression in both patients. Sural nerve biopsy revealed the characteristic tomaculous swellings in both patients. DNA analysis showed that both patients have a deletion in chromosome 17p11.2 which is found in the majority of HNPP cases. In light of the common molecular defect, the different clinical symptomatology of the two patients is discussed.

Adult↗
PubMed1991

The metabolism of fibroblasts from normal and fibrotic skin is inhibited by minoxidil in vitro.

The effects of minoxidil in vitro were studied using fibroblasts grown from the lesional skin of patients with lichen sclerosus et atrophicus, morphoea and from the skin of normal individuals. The proliferation of all fibroblast lines over 3 days was inhibited in proportion to the concentration of minoxidil, being 20% or less of controls at 1 mM, where cell viability was only marginally reduced (84 +/- 2% vs. 88 +/- 2% (SEM) in controls). At 5 mM there was usually a net loss of cells and only 72% of those remaining were viable. In contrast, minoxidil at 0.1-1 mM stimulated the proliferation of foreskin keratinocytes by up to 130%. Contraction of collagen lattices containing the three types of fibroblasts was inhibited by 22-26% with 1 mM minoxidil after 5 days and by 50-94% with 5 mM. Secretion of glycosaminoglycans by normal fibroblasts showed concentration-dependent reduction, being 25 +/- 6% of that of untreated cultures with 1 mM minoxidil. These findings show that minoxidil has a range of inhibitory effects on both normal and abnormal skin fibroblasts in vitro, which contrast with its stimulation of skin epithelial cells, and support suggestions that it may provide a useful topical treatment for keloids and other fibroses.

Cell Division↗
PubMed1991

Coexistence of pemphigus vulgaris, malignant melanoma and low-grade lymphoma.

A 53-year-old female patient with pemphigus vulgaris under continuous immunosuppressive therapy for about 2 years presented a superficial spreading malignant melanoma on a pre-existing melanocytic naevus. After surgical removal of the inguinal lymph node group, a diffuse low-grade polymorphous immunocytoma was proved both histologically and immunocytochemically. The possible induction mechanisms are discussed.

Female↗
PubMed1988

Delayed hypersensitivity and differences of histologic pattern in allergic cutaneous vasculitis.

Fourteen patients with allergic cutaneous vasculitis of either the polymorphonuclear (PMN)- or the mononuclear (MN)-predominant type were studied as regards the following parameters: the disease duration, histology, monoclonal antibody typing of the mononuclear cell infiltrate from recent lesions, and the delayed hypersensitivity (DH) response, assessed both by recall antigens (tuberculin type) and the dinitrochlorobenzene skin test. From the results, it was shown that in PMN-predominant vasculitis, DH reactions were well elicited, whereas in MN-predominant vasculitis, DH skin reactions were somehow impaired. In MN-predominant cases, many OKT3+, OKT4+, OKT8+, and OKM1+ cells were usually seen to surround the skin vessels, whereas in PMN-predominant cases, rare OKT8+, OKT4+, or OKM1+ cells were seen in the dermis. The epidermal dendritic cell system, as revealed by the Na(1)34 monoclonal antibody, was unaffected in both types of allergic cutaneous vasculitis.

Adult↗
PubMed1986

Serum testosterone and sex hormone binding globulin levels in women with androgenetic alopecia.

Serum levels of testosterone and sex hormone binding globulin (SHBG) were assessed in eight women suffering from male pattern alopecia. Eight healthy women of similar age served as controls. A statistically non-significant increase was observed in serum testosterone levels as compared with those of the controls (p greater than 0.1). On the other hand, a statistically significant fall was observed in serum SHBG levels as compared with those of the controls (p less than 0.001).

Adult↗
PubMedDate not supplied

New information on the value of plaque characterisation--relation to symptoms.

This paper reviews the literature on the significance of carotid plaque echomorphology and degree of stenosis in relation to the different types of cerebrovascular symptomatology (amaurosis fugax, hemispheric transient ischaemic attacks, stroke) and the asymptomatic status. It provides evidence that amaurosis fugax is associated with hypoechoic and severely stenosed plaques, the hemispheric transient ischaemic attacks and stroke are associated with plaques of intermediate echodensity and stenosis while the asymptomatic status is associated with hyperechoic and moderately stenosed plaque. It lends support to the notion that plaque hypoechoicity is associated with embologenicity. It supports the view that the severe carotid stenosis facilitates the opening of the cerebral collateral circulation and that amaurosis fugax is associated with an "opened" cerebral collateral supply as contrasted to the cerebrovascular symptomatology. It proposes the inclusion of the cerebral collateral circulation as a stroke risk factor along with the plaque echomorphology and the degree of stenosis in the natural history studies of asymptomatic individuals with carotid bifurcation plaques.

Amaurosis Fugax↗