Effects of green tea and black tea on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone bioactivation, DNA methylation, and lung tumorigenesis in A/J mice

Previous studies in our laboratory showed that decaffeinated green tea and black tea extracts inhibited 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced tumorigenicity in A/J female mice. In order to understand the mechanism of the inhibitory action, we examined the effects of decaffeinated green tea, black tea, and tea components on the metabolic activation of NNK in vitro and in vivo in this animal model. When added to incubation mixtures containing mouse lung microsomes, decaffeinated green tea and black tea extracts and their fractions, at concentrations up to 0.4 mg/ml, inhibited NNK oxidation and NNK-induced DNA methylation. Among the tea components examined, (-)-epigallocatechin-3-gallate was the most potent inhibitor with 50% inhibitory concentrations of about 0.12 mM for both NNK oxidation and DNA methylation. At these concentrations, (-)-epigallocatechin-3-gallate inhibited the catalytic activities of several P450 enzymes and was more potent against P450 1A and 2B1 than 2E1. When decaffeinated green or black tea extracts were given to female A/J mice as the sole source of drinking fluid before an i.p. injection of NNK (100 mg/kg body weight), a statistically significant inhibition of lung DNA methylation, however, was not observed, although a significant reduction in lung tumor multiplicity was observed. The results suggest that, although inhibition of the metabolic activation of NNK and the subsequent DNA alkylation by tea extracts can be demonstrated in vitro, this mechanism may not be important for the inhibitory action of tea against lung tumorigenesis.     

Respiratory response to cigarette smoking among adolescent smokers: a pilot study

BACKGROUND: Because cigarette smoking affects the respiratory system earlier than many other systems of the human body, an attempt was made to identify objective and subjective respiratory problems among adolescent smokers. METHODS: Two studies based on a pulmonary function test (PFT), respiratory symptom assessment, and other smoking-related variables were undertaken. Study 1 involved cigarette smokers (N = 18, 22% males, mean age 18.7 years) from a freshman college class who participated in an acute smoking experiment that involved performing a PFT before and after smoking a single cigarette. Study 2 was performed on a combined group of vocational-technical high school students and freshman college students (N = 44, 48% males, mean age 17.8 years) where PFT parameters, respiratory symptoms, and smoking-related health vulnerability were assessed among smokers vs nonsmokers. RESULTS: In Study 1, the average reduction across PFT parameters was 4.4% and the mean estimated lung age increased from 27.15 to 29.84 years. In Study 2, a consistent trend toward reduction of PFT values among smokers vs nonsmokers was observed; the mean forced expiratory volume in 1 sec/forced vital capacity ratio (90.51% vs 94.59%), peak expiratory flow rate (80.32% vs 92.06%), and flow rate of 50% of forced vital capacity (88.39% vs 102.81%) differed significantly. Significant differences in respiratory symptoms were also observed among smokers vs nonsmokers. CONCLUSIONS: The beginning of respiratory health disorders can be identified among adolescent smokers. These findings might provide important clues on how to improve outcomes from health care provider-based adolescent smoking cessation counseling.     

Respiratory distress of the newborn

ATP-sensitive potassium (KATP) channels are reversibly inhibited by intracellular ATP. Agents that interact with sulfhydryl moieties produce an irreversible inhibition of KATP channel activity when applied to the intracellular membrane surface. ATP appears to protect against this effect, suggesting that the cysteine residue with which thiol reagents interact may either lie within the ATP-binding site or be inaccessible when the channel is closed. We have examined the interaction of the membrane-impermeant thiol-reactive agent p-chloromercuriphenylsulphonate (pCMPS) with the cloned beta cell KATP channel. This channel comprises the pore-forming Kir6.2 and regulatory SUR1 subunits. We show that the cysteine residue involved in channel inhibition by pCMPS resides on the Kir6.2 subunit and is located at position 42, which lies within the NH2 terminus of the protein. Although ATP protects against the effects of pCMPS, the ATP sensitivity of the KATP channel was unchanged by mutation of C42 to either valine (V) or alanine (A), suggesting that ATP does not interact directly with this residue. These results are consistent with the idea that C42 is inaccessible to the intracellular solution, and thereby protected from interaction with pCMPS when the channel is closed by ATP. We also observed that the C42A mutation does not affect the ability of SUR1 to endow Kir6.2 with diazoxide sensitivity, and reduces, but does not prevent, the effects of MgADP and tolbutamide, which are mediated via SUR1. The Kir6.2-C42A (or V) mutant channel may provide a suitable background for cysteine-scanning mutagenesis studies.     

Isolation and characterization of tilapia (Oreochromis mossambicus) insulin-like growth factors gene and proximal promoter region

It has been shown that both multidrug resistance-associated protein (MRP1) and canalicular multispecific organic anion transporter (cMOAT/MRP2) have the ability to extrude glutathione conjugates (GS-X pump activity)from cells. Therefore, they play an important role in the detoxification of xenobiotics. Using mrp1-knockout mice, it has recently been shown that MRP1/mrp1 has an important role in the export of leukotriene C4 (LTC4), a mediator of inflammation, and in protecting the body from a number of toxins, including several antitumor drugs. A comparison of the transport properties across the bile canalicular membrane in normal and mutant rats, whose cMOAT function is hereditarily defective, has shown that the physiologic role of cMOAT is to excrete LTC4, bilirubin glucuronides, 171-estradiol-170-D-glucuronide, and reduced folates. In the present review article, we summarize the substrate specificity and mechanism for the transport of these GS-X pumps, focusing on the pharmacologic and physiologic aspects. The transport activity mediated by cMOAT is also discussed in terms of a comparison between membrane vesicles from hepatocytes and cMOAT-transfected cells, and we also briefly examine the possible role of MRPI and cMOAT in the extrusion of reduced glutathione.     

Closed ruptures of the flexor digitorum tendons: MRI evaluation

OBJECTIVE: To assess the MRI findings in cases of closed rupture of the flexor digitorum tendons (FDT). PATIENTS AND DESIGN: Ten patients with a clinical suspicion of rupture of FDT underwent MRI before surgery. None of the patients presented a skin injury. Fingers were imaged using axial T1-weighted SE sequences, three-dimensional GE images, and curved reconstructions. RESULTS: Twelve FDT had surgical confirmation of rupture. Flexor digitorum profundus (FDP) and flexor pollicis longus (FPL) tendons were more frequently ruptured (n=8) than flexor digitorum superficialis (FDS) tendons (n=4). MR images accurately depicted the level of the rupture. The gap between the tendon ends (mean 45 mm, range 21-70 mm) was assessed best with curved reconstructions and was well correlated with the surgical findings. The proximal end mainly retracted into the palm or the carpal tunnel (n=8), and less frequently into the digital canal (n=4). In two cases, the proximal end curled up in the palm, clinically simulating a rupture of a lumbrical muscle in one case. MRI also showed the appearance of the adjacent tendons. CONCLUSION: MRI accurately depicted the level of rupture and the gap between the tendon ends, which assisted the surgical choice between suture, graft or tendon transfer.     

Initiation of spontaneous epileptiform activity in the neocortical slice

Cortical local circuitry is important in epileptogenesis. Voltage-sensitive dyes and fast imaging were used to visualize the initiation of spontaneous paroxysmal events in adult rat neocortical slices. Although spontaneous paroxysmal events could start from anywhere in the preparation, optical imaging revealed that all spontaneous events started at a few confined initiation foci and propagated to the whole preparation. Multielectrode recording over hundreds of spontaneous events revealed that often two or three initiation foci coexisted in each preparation (n = 10). These foci took turns being dominant; the dominant focus initiated the majority of the spontaneous paroxysmal events during that period. The dominant focus and dynamic rearrangement of foci suggest that the initiation of spontaneous epileptiform events involves a local multineuronal process, perhaps with potentiated synapses.     

Hemichorea and striatal infarction

We present two cases of hemichorea associated with an arterial ischaemic stroke in the controlateral striatum and we reviewed 28 similar cases in the literature. The pathogenesis of this movement disorder involves the gabaergic and enkephalinergic neurons of the striatal matrice which mainly projects on the external globus pallidus. A destruction of the striatal neurons of the indirect striato-thalamo-cortical ways may reduce their inhibitory out flow on normal inhibited thalamic and cortical structures and then create abnormal choreiform movements. The scarcity of this phenomenon can be explained by: 1) the repartition of the enkephalinergic local circuit neurons which represent but one third of the motor striatal neuronal population; 2) the type of vascularisation which often involves larger territories in the striatum and the globus pallidus or the anterior limb of the internal capsule. These abnormal movements are often transient because of the regulation of accessory striato-nigro-striatal, cortico-striato-nigro-thalamo-cortical and cortico-luysin circuits. More over, because these hypotheses and after having reviewed all such cases in literature, choreic movements to pure thalamic involvement are to be questioned.     

An alpha 5 beta 1-like integrin receptor mediates the binding of less pathogenic Candida species to fibronectin

The present study was undertaken to investigate whether less pathogenic Candida species (C. tropicalis, C. stellatoidea, C. krusei and C. glabrata) express a fibronectin receptor (FNr) antigenically related to alpha 5 beta 1 integrin, which mediates their binding to fibronectin (FN). By flow cytometric analysis, a monoclonal antibody (MAb) directed against human alpha 5 integrin subunit (clone SAM-1) and two different antisera to FNr positively stained C. tropicalis, C. stellatoidea and C. glabrata, with the greatest expression observed for C. tropicalis. No or only marginal immunoreactivity was found on C. krusei. C. tropicalis, C. stellatoidea, C. glabrata, but not C. krusei yeasts specifically adhered to FN; higher levels of adhesion were found for C. tropicalis and C. stellatoidea with respect to C. glabrata. Less pathogenic Candida spp. bound to the Arg-Gly-Asp (RGD) containing 120-kDa fragment of FN and adhesion to intact FN was markedly inhibited by Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP), but not by Gly-Arg-Gly-Glu-Ser-Pro (GRGESP) peptides. In addition, anti-alpha 5 SAM-1 MAb and both anti-FNr antisera strongly blocked binding of less pathogenic Candida spp. to FN. Overall, these results indicate that less pathogenic Candida spp., including C. tropicalis, C. stellatoidea and C. glabrata, express a receptor antigenically related to alpha 5 beta 1 integrin which mediates their adhesion to FN.     

Unresolved questions in the indications for the conservative treatment of invasive cancer of the breast

The majority of patients with breast cancer can be treated by partial mastectomy and radiation therapy. The choice of the treatment involves the estimation of the risk for intramammary recurrence and the ability to achieve satisfactory cosmetic result. Patient selection in breast conserving therapy is dependent on clinical and histologic characteristics of the tumor, but many times the therapeutic decision is not easy. We present a review of the literature in order to try to resolve some controversed questions about breast conservation in relation to tumor size, margin status, tumor location, multicentricity, histologic subtype or presence of extensive intraductal component, age of patients and genetic factors.     

Effect of intravenous immunoglobulin G on natural killer cell cytotoxicity in vitro in women with recurrent spontaneous abortion

Intravenous immunoglobulin (IVIg) has been used to treat women with recurrent spontaneous abortion (RSA), particularly for women with elevated natural killer (NK) cells. We investigated the effect of IVIg on peripheral blood NK cell activity in vitro in women with RSA. 51Cr-release assays using K562 in the presence of varying concentrations of IVIg were performed using PBL from 16 women with RSA. Antibody dependent cellular cytotoxicity (ADCC) was evaluated using Daudi cells. Effectors and targets were preincubated with IVIg. Binding of IVIg to K562 and Daudi was evaluated by flow cytometry. The effect of K562 absorbed IVIg on NK activity was compared to that of non-absorbed IVIg. NK cytotoxicity and ADCC in the presence of F(ab')2 fragments were compared with those in the presence of intact IVIg. IVIg produced a significant, dose dependent inhibition of NK activity in vitro. Inhibition of NK activity occurred when effectors but not targets were preincubated with IVIg. IVIg binds to K562 and Daudi. IVIg increased ADCC when targets but not effectors were incubated with IVIg. K562 absorbed IVIg produced more inhibition of NK cytotoxicity than non-absorbed IVIg. Suppression of NK cytotoxicity by F(ab')2 was as effective as that of IVIg. However, F(ab')2 did not increase ADCC. IVIg effectively reduces peripheral blood NK cytotoxicity in vitro. Inhibition of NK cytotoxicity is mediated at the effector cell level through the antigen binding portion of the immunoglobulins. Women with RSA and elevated NK cells may benefit from IVIg treatment.