[Rhinophyma : Successful treatment with low-dose oral isotretinoin]. / Rhinophym : Therapieerfolg mit niedrig dosiertem systemischem Isotretinoin.

Rhinophyma is a form of rosacea and is often cosmetically disfiguring. There are various therapeutic ablation modalities. Surgery is often associated with down-time and side-effects. We describe successful treatment with low-dose isotretinoin as a safe alternative with a lower risk of complications. We also discuss the advantages and disadvantages of various therapeutic modalities.

Is non-ablative 1550-nm fractional photothermolysis an effective modality to treat melasma? Results from a prospective controlled single-blinded trial in 51 patients.

BACKGROUND: Melasma is a common benign pigmentary disease and can pose a substantial therapeutic challenge. Although the use of non-ablative fractional photothermolysis (NFP) has gained much popularity, there are still very few evidence-based data supporting NFP in the treatment of melasma. OBJECTIVE: To assess the efficacy and safety of NFP for the treatment of melasma in a controlled observer-blinded parallel-group study. PATIENTS AND METHODS: Fifty-one patients [90.2% women, 9.8% men; mean age 40.3±6.1 (control group) and 41.7±11.4 (treatment group)] received a broad-spectrum sunscreen either alone (n=25; 49.0%) or in combination with a 1550-nm NFP treatment (n=26; 51.0%) [energy: 15 mJ/microthermal zone (MTZ); total density: 1048 MTZs/cm(2); density per pass: 131 MTZs/cm(2); number of passes: 8; total coverage: 20%]. Four sessions of NFP treatment were performed at 3-week intervals on each subject in the treatment group. Patients were evaluated at baseline and 12 weeks after final treatment. The primary efficacy variables were the Melasma Area and Severity Index (MASI) and the physician's global assessment (PGA); secondary efficacy variables were the patients' subjective assessment of improvement and patient satisfaction. Safety was evaluated through the reporting of adverse events. RESULTS: The percentage of subjective improvement was virtually identical in both groups: one-third of the patients reported a 'marked improvement' and another half reported 'some improvement'. Twenty-three patients in each group declared that they were 'satisfied' with the treatment result. The MASI corroborated the patients' subjective estimate, both in terms of the degree of improvement and the lack of a group difference. In both groups, the MASI score and the PGA were reduced significantly after therapy, and the reduction was also clinically relevant. No serious side-effects were reported in either group. CONCLUSION: Our findings do not support the hypothesis of NFP providing a substantial benefit in treating melasma when compared with the lone application of a broad-spectrum sunscreen.

[Recurrent pyogenic granuloma. Treatment at difficult anatomic sites with the long-pulsed Nd:YAG laser (1064 nm)]. / Therapieresistentes Granuloma pyogenicum. Behandlung an schwierigen anatomischen Lokalisationen mit dem lang gepulsten Nd:YAG-Laser (1064 nm).

Treatment of pyogenic granuloma is still difficult as lesions tend to recur. There are various means of treatment: surgical, cryotherapy, topical agents and various lasers. We successfully treated two recurrent pyogenic granulomas at difficult sites (on the tip of the finger and ear) using the Nd: YAG laser (1064 nm). Several treatments under local anesthesia were needed. The energy was increased until coagulation was visible. The laser treatment led to complete resolution.

Chitosan encapsulation modulates the effect of capsaicin on the tight junctions of MDCK cells.

Capsaicin has known pharmacological effects including the ability to reversibly open cellular tight junctions, among others. The aim of this study was to develop a strategy to enhance the paracellular transport of a substance with low permeability (FITC-dextran) across an epithelial cell monolayer via reversible opening of cellular tight junctions using a nanosystem comprised by capsaicin and of chitosan. We compared the biophysical properties of free capsaicin and capsaicin-loaded chitosan nanocapsules, including their cytotoxicity towards epithelial MDCK-C7 cells and their effect on the integrity of tight junctions, membrane permeability and cellular uptake. The cytotoxic response of MDCK-C7 cells to capsaicin at a concentration of 500 µM, which was evident for the free compound, is not observable following its encapsulation. The interaction between nanocapsules and the tight junctions of MDCK-C7 cells was investigated by impedance spectroscopy, digital holographic microscopy and structured illumination fluorescence microscopy. The nanocapsules modulated the interaction between capsaicin and tight junctions as shown by the different time profile of trans-epithelial electrical resistance and the enhanced permeability of monolayers incubated with FITC-dextran. Structured illumination fluorescence microscopy showed that the nanocapsules were internalized by MDCK-C7 cells. The capsaicin-loaded nanocapsules could be further developed as drug nanocarriers with enhanced epithelial permeability.

Primary and beta-secondary deuterium isotope effects in N-deethylation reactions.

Lidocaine (1), labeled specifically with deuterium in the alpha-methylene (lidocaine-d4,2) and beta-methyl (lidocaine-d6,3) carbon atoms of the terminal amino group, was used to probe the mechanism of oxidative N-deethylation by rat liver microsomes. The reaction rates were determined by measuring the formation of acetaldehyde colorimetrically. This general assay for oxidative N-deethylation reactions has the advantages of being rapid, producing a relatively stable colored derivative and being linear over the range of 0.25-4 mug of acetaldehyde formed per milliliter of incubate. Deuterium substitution at the methylene carbon atoms, the presumed site of initial oxygen insertion, revealed a kH/kD = 1.49 +/- 0.11 and a KmD/KmH = 1.23. Deuterium substitution on the terminal methyl groups showed a kH/kD = 1.52 +/- 0.10 and a KmD/KmH = 0.92. The results are explained in terms of both primary and secondary isotope effects on a possible rate-determining step in the N-deethylation sequence.

Synthesis and thin-layer chromatographic ultraviolet, and mass spectral properties of the anticoagulant phenprocoumon and its monohydroxylated derivatives.

Phenprocoumon and all of its aromatic monohydroxylated derivatives have been synthesized and analyzed by TLC, uv, and chemical ionization mass spectroscopy. By utilization of various combinations of these analytical techniques all of the titled compounds can be uniquely identified.

Biotransformation of phenprocoumon in the rat.

The metabolic fate of phenprocoumon [3-(alpha-ethylbenzyl)-4-hydroxycoumarin] in the rat is described. The major metabolites, 4',-6-,7-, and 8-hyproxyphenprocoumon, have been identified yb mass spectrometry, TLC, and uv and compared with authentic smaples. Metabolites are mainly excreted via the feces. The results are compared with those previously reported for warfarin.

Immunohistochemical localization of carboxylesterase in the nasal mucosa of rats.

The enzymatic esterase activity of carboxylesterases is integral to the nasal toxicity of many esters used as industrial solvents or in polymer manufacture, including propylene glycol monomethyl ether acetate, dimethyl glutarate, dimethyl succinate, dimethyl adipate, and ethyl acrylate. Inhalation of these chemicals specifically damages the olfactory mucosa of rodents. We report the localization and differential distribution of a 59 KD carboxylesterase in nasal tissues of the rat by immunohistochemistry. Rabbit antiserum against the 59 KD rat liver microsomal carboxylesterase bound most prominently to the olfactory mucosa when applied to decalcified, paraffin-embedded sections of rat nasal turbinates. Within the olfactory mucosa, anti-carboxylesterase did not bind to sensory neurons, the target cell for ester-initiated toxicity; these cells apparently lack carboxylesterase. Instead, the antibody was preferentially bound by cells of Bowman's glands and sustentacular epithelial cells which are immediately adjacent to the olfactory nerve cells. In contrast, non-olfactory tissues (respiratory mucosa and squamous epithelium), which are more resistant to the toxicity of esters, had less carboxylesterase content. The distribution of immunoreactivity correlated well with the distribution of carboxylesterase catalytic activity described elsewhere. These findings help to link the metabolic fate of inhaled esters to the site-specific pathological findings that follow exposure to such chemicals.

Association of anti-58 kDa endoplasmic reticulum antibodies with halothane hepatitis.

We recently showed that when rats were administered the inhalation anesthetic halothane, a 58 kDa liver endoplasmic reticulum protein became covalently trifluoroacetylated by the trifluoroacetyl chloride metabolite of halothane. Although the 58 kDa protein showed 99% identity to that of the deduced amino acid sequence of a cDNA reported to correspond to phosphatidylinositol-specific phospholipase C-alpha, it did not have phosphatidylinositol-specific phospholipase C activity. It was concluded that the reported cDNA of phosphatidylinositol-specific phospholipase C-alpha actually encoded for the 58 kDa endoplasmic reticulum protein of unknown function. Other researchers have come to the same conclusion and have shown that the 58 kDa protein has protein disulfide-isomerase and protease activities. We now report that patients with halothane hepatitis have serum antibodies that react with both purified trifluoroacetylated and native rat liver 58 kDa proteins. These results suggest that when patients are exposed to halothane a human liver orthologue of the rat liver trifluoroacetylated-58 kDa protein is formed. In certain patients, this protein may become immunogenic and lead to the formation of specific antibodies and or specific T-cells, which may react with both trifluoroacetylated and native 58 kDa proteins, and ultimately be responsible, at least in part, for the hepatitis caused by halothane.

The topography of trifluoroacetylated protein antigens in liver microsomal fractions from halothane treated rats.

Sera from patients with halothane hepatitis contain immunoglobulin G (IgG) antibodies to trifluoroacetylated liver microsomal proteins of 100, 76, 59, 57 and 54 kDa, which are produced as a consequence of metabolism of halothane to trifluoroacetyl halide by cytochrome(s) P450. In the present study, the membrane topographies of the various antigens in rat liver microsomal fractions were investigated. Liver microsomal fractions from rats treated with halothane in vivo, and rat liver microsomal fractions which had been incubated with halothane in vitro, were used as the source of trifluoroacetyl antigens. The antigens were detected by immunoblotting. Whereas the 100, 76, 59 and 57 kDa antigens were solubilized from the microsomal membrane by either 0.1 M sodium carbonate or 0.1% (w/v) sodium deoxycholate, the 54 kDa antigen was not solubilized by 0.1% (w/v) sodium deoxycholate. In intact microsomal fractions, the 100, 76, 59 and 57 kDa antigens were not degraded appreciably by trypsin unless detergent was added to permeabilize the microsomal membrane. These results indicate that the 54 kDa antigen is an integral membrane protein, whereas the 100, 76, 59 and 57 kDa antigens are peripheral membrane proteins situated within the lumen of microsomal vesicles, and hence presumably located within the lumen of the endoplasmic reticulum in vivo.

Two-dimensional J-resolved nuclear magnetic resonance spectral study of two bromobenzene glutathione conjugates.

The application of two-dimensional J-resolved nuclear magnetic resonance spectroscopy to determine the structure of two bile metabolites isolated from rats injected interperitoneally with bromobenzene is described. The structures of the two molecules are obtained unambiguously from the proton-proton spin coupling constants. This paper discusses the fundamentals of the technique and demonstrates the resolution of small long-range coupling constants.

Classification of carotid bifurcation disease using quantitative Doppler spectrum analysis.

Spectrum analysis of continuous-wave Doppler recordings from the region of the carotid bifurcation was used to classify the degree of stenosis in the internal (ICA) and external (ECA) carotid arteries. Measurements of systolic peak frequency, end-diastolic frequency, and the degree of spectral broadening were used to define five ICA disease categories: 0% to 15% diameter reduction (DR), 16% to 49% DR, 50% to 80% DR, greater than 80% DR, and occlusion. The results were compared to contrast arteriography in 122 patients (243 arteries). The agreement with angiography in classifying ICA stenosis was 82%. Doppler spectrum analysis identified 96% of hemodynamically significant disease (greater than 50% DR) in the ICA and ECA and 97% of ICA occlusions. Attention to the common carotid artery waveform and the ICA diastolic frequency improved the accuracy of predicting greater than 80% DR and occlusion of the ICA. Noninvasive classification of carotid bifurcation disease is useful in clinical decision making to select the angiographic technique most likely to accurately define disease morphology and to follow up patients for disease progression.

Determination of the rate of release of intra-oral mercury vapor from amalgam.

The experimental and analytical difficulties associated with the measurement of mercury vapor in the oral cavity are considerable. In the present paper, the objective was to measure the amount of intra-oral mercury vapor in subjects with amalgams, by means of two sets of equipment based on different functional principles. In addition, it was found that the type of mercury source prevalent in the oral cavity had to be evaluated. The measuring technique used to obtain correct results is discussed, and an evaluation of the conditions for the application of the measuring equipment available was made. It was found that the amount of mercury released from the oral cavity was time-dependent. Furthermore, the amount of mercury released with the time kept constant was almost independent of the pumping flow rate up to 8 L/min. It was found that the tissue, saliva, and the amalgam restorations were not depleted of mercury during the measuring time. The results of the Mercollector-Mercometer measurements carried out on seven subjects with nine or more occlusal surfaces restored with dental amalgam and on three subjects without any amalgam restorations revealed that the rate of mercury release was in the range 0.03-0.34 ng/sec in the former group and less than 0.01 ng/sec in the latter. Based on the experimental results and on theoretical considerations, it was concluded that the amount of mercury released per time unit is the only quantity measurable.

Model of mercury vapor transport from amalgam restorations in the oral cavity.

A model of the oral cavity was used as the basis for a discussion of the conditions prevalent during the transport of mercury vapor from amalgam restorations via the saliva to the gas phase of the oral cavity during respiration or during pumping of air through the mouth. It was found that the mercury diffusion rate through the saliva layer is independent of the air flow rate through the oral cavity. Mercury appears to be transported as atoms both in the aqueous phase of saliva and in the gas phase. The majority of the mercury atoms reaching the gas phase appears to originate directly from the surface of the amalgam restorations, passing through the saliva layer, while only a minority originates from mercury dissolved in the aqueous phase. The amount of mercury released per unit of time to the gas phase was shown to be independent of the air flow rate during respiration and pumping. Furthermore, the released mercury atoms are distributed partly to the gas phase, from which they are respired to the lungs and the environment, and partly to the saliva and the gastro-intestinal tract, by swallowing.

Cloning and sequencing of a human liver carboxylesterase isoenzyme.

A human liver lambda gt11 library was screened with antibodies raised to a purified rat liver carboxylesterase, and several clones were isolated and sequenced. The longest cDNA contained an open reading frame of 507 amino acids that represented 92% of the sequence of a mature carboxylesterase protein. This sequence possessed many structural features that are highly conserved among rabbit and rat liver carboxylesterase proteins, including Ser, His, and Asp residues that comprise the active site, two pairs of Cys residues that may participate in disulfide bond formation, and one Asn-Xxx-Thr site for N-linked carbohydrate addition. When the clone was used to probe human liver genomic DNA that had been digested with various restriction enzymes, many hybridizing bands of differing intensities were observed. The results suggest that the carboxylesterases exist as several isoenzymes in humans, and that they are encoded by multiple genes.

Oxidation of carbon tetrachloride, bromotrichloromethane, and carbon tetrabromide by rat liver microsomes to electrophilic halogens.

In order to determine whether CCl4, CBrCl3, CBr4 or CHCl3 undergo oxidative metabolism to electrophilic halogens by liver microsomes, they were incubated with liver microsomes from phenobarbital pretreated rats in the presence of NADPH and 2,6-dimethylphenol. The analysis of the reaction mixtures by capillary gas chromatography mass spectrometry revealed that 4-chloro-2,6-dimethylphenol was a metabolite of CCl4 and CBrCl3 whereas 4-bromo-2,6-dimethylphenol was a metabolite of CBr4. The formation of the metabolites was significantly decreased when the reactions were conducted with heat denatured microsomes, in the absence of NADPH or under an atmosphere of N2. These results indicate that the chlorines of CBrCl3 and CCl4 and the bromines of CBr4 are oxidatively metabolized by rat liver microsomes to electrophilic and potentially toxic metabolites.

Carbon-13 nuclear magnetic resonance studies of spironolactone and several related steroids.

The 13C chemical shifts for all the carbon atoms is spironolactone have been assigned. Assignments for nine additional steroids which include the C-7 beta isomer of spironolactone, its C-7 thiol hydrolysis product, the 7 alpha-thioacetate derivative of testosterone and its thiol hydrolysis product are also reported.

Inactivation of cytochrome P-450 by 2-isopropyl-4-pentenamide and other xenobiotics leads to heme-derived protein adducts.

When cytochrome P-450 in phenobarbital-induced rat liver microsomes was destroyed by 2-isopropyl-4-pentenamide (AIA) in vitro, 50% of the degraded heme was recovered as heme-derived products irreversibly bound to microsomal proteins. In contrast, less than 50% of the degraded heme was accounted for as N-alkylated porphyrins. Furthermore, 64% of the irreversibly bound products was bound specifically to a 54-kD form of cytochrome P-450. Several other compounds which have been reported to destroy cytochrome P-450 by forming N-alkylated porphyrins also produced heme-derived protein adducts. These findings indicate that the formation of heme-derived protein adducts may represent an important pathway for the irreversible degradation of cytochrome P-450 by many xenobiotics.

Stereoselective formation of bromobenzene glutathione conjugates.

Two bromobenzene-glutathione conjugates have been detected as both in vivo and in vitro metabolites of bromobenzene. Separation and purification by high pressure liquid chromatography (HPLC) and analysis by 13C and 1H-NMR spectroscopy indicated that the metabolites are trans-3-bromo-6-(glutathion-S-yl)-cyclohexa-2,4-dien-1-ol and trans-4-bromo-6-(glutathion-S-yl)-cyclohexa-2,4-dien-1-ol. The two conjugates are formed in unequal amounts; over a dose range of 25-500 mg/kg the ratio of the two conjugates excreted into bile in 6 h was 1.6 +/- 0.1 (mean +/- S.E.). Pretreatment of rats with either phenobarbital or 3-methyl-cholanthrene did not significantly alter the ratio of the two conjugates excreted into bile. When bromobenzene was incubated with rat liver microsomes and glutathione, the same two conjugates were formed in the presence but not in the absence of 100 000 x g supernatant. Furthermore, in the presence of 100 000 x g supernatant from control animals, microsomes from rats treated with phenobarbital formed both conjugates 6 times more rapidly than did microsomes from control rats, whereas microsomes from rats treated with 3-methylcholanthrene formed both conjugates less rapidly than did those from control rats. Thus, the data suggest that both conjugates are formed via bromobenzene 3,4-oxide and that their formation requires in liver cytosol.

A new concept of cellular uptake and intracellular trafficking of long-chain fatty acids.

Fatty acids are the main structural and energy sources of the human body. Within the organism, they are presented to cells as fatty acid:albumin complexes. Dissociation from albumin represents the first step of the cellular uptake process, involving membrane proteins with high affinity for fatty acids, e.g., fatty acid translocase (FAT/CD 36) or the membrane fatty acid-binding protein (FABPpm). According to the thus created transmembrane concentration gradient, uncharged fatty acids can flip-flop from the outer leaflet across the phospholipid bilayer. At the cytosolic surface of the plasma membrane, fatty acids can associate with the cytosolic FABP (FABP(c)) or with caveolin-1. Caveolins are constituents of caveolae, which are proposed to serve as lipid delivery vehicles for subcellular organelles. It is not known whether protein (FABP(c))- and lipid (caveolae)-mediated intracellular trafficking of fatty acids operates in conjunction or in parallel. Channeling fatty acids to the different metabolic pathways requires activation to acyl-CoA. For this process, the family of fatty acid transport proteins (FATP 1-5/6) might be relevant because they have been shown to possess acyl-CoA synthetase activity. Their variable N-terminal signaling sequences suggest that they might be targeted to specific organelles by anchoring in the phospholipid bilayer of the different subcellular membranes. At the highly conserved cytosolic AMP-binding site of FATP, fatty acids are activated to acyl-CoA for subsequent metabolic disposition by specific organelles. Overall, fatty acid uptake represents a continuous flow involving the following: dissociation from albumin by membrane proteins with high affinity for fatty acids; passive flip-flop across the phospholipid bilayer; binding to FABP(C) and caveolin-1 at the cytosolic plasma membrane; and intracellular trafficking via FABP(c) and/or caveolae to sites of metabolic disposition. The uptake process is terminated after activation to acyl-CoA by the members of the FATP family targeted intracellularly to different organelles.