bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative phosphoproteomics of vasopressin-sensitive renal cells: Regulation of aquaporin-2 phosphorylation at two sites
Authors: Hoffert Jason D. , Pisitkun Trairak , Wang Guanghui , Shen Rong-Fong , Knepper Mark A.
Published: April 2006

Protein phosphorylation plays a key role in vasopressin signaling in the renal-collecting duct. Large-scale identification and quantification of phosphorylation events triggered by vasopressin is desirable to gain a comprehensive systems-level understanding of this process. We carried out phosphoproteomic analysis of rat inner medullary collecting duct cells by using a combination of phosphopeptide enrichment by immobilized metal affinity chromatography and phosphorylation site identification by liquid chromatography-mass spectrometry
n
neutral loss scanning. A total of 714 phosphorylation sites on 223 unique phosphoproteins were identified from inner medullary collecting duct samples treated short-term with either calyculin A or vasopressin. A number of proteins involved in cytoskeletal reorganization, vesicle trafficking, and transcriptional regulation were identified. Previously unidentified phosphorylation sites were found for membrane proteins essential to collecting duct physiology, including eight sites among aquaporin-2 (AQP2), aquaporin-4, and urea transporter isoforms A1 and A3. Through label-free quantification of phosphopeptides, we identified a number of proteins that significantly changed phosphorylation state in response to short-term vasopressin treatment: AQP2, Bclaf1, LRRC47, Rgl3, and SAFB2. In the presence of vasopressin, AQP2 monophosphorylated at S256 and diphosphorylated AQP2 (pS256/261) increased in abundance, whereas AQP2 monophosphorylated at S261 decreased, raising the possibility that both sites are involved in vasopressin-dependent AQP2 trafficking. This study reveals the practicality of liquid chromotography-mass spectrometry
n
neutral loss scanning for large-scale identification and quantification of protein phosphorylation in the analysis of cell signaling in a native mammalian system.
Congenital progressive hydronephrosis (
cph
) is caused by an S256L mutation in aquaporin-2 that affects its phosphorylation and apical membrane accumulation
Authors: McDill Bradley W. , Li Song-Zhe , Kovach Paul A. , Ding Li , Chen Feng
Published: April 2006

Congenital progressive hydronephrosis (
cph
) is a spontaneous recessive mutation that causes severe hydronephrosis and obstructive nephropathy in affected mice. The mutation has been mapped to the distal end of mouse chromosome 15, but the mutated gene has not been found. Here, we describe the identification of a single base pair change in
aquaporin-2
(
Aqp2
) in
cph
mutants through genetic linkage mapping. The C-T change led to the substitution of a Ser (S256) by a Leu in the cytoplasmic tail of the Aqp2 protein, preventing its phosphorylation at S256 and the subsequent accumulation of Aqp2 on the apical membrane of the collecting duct principal cells. The interference with normal trafficking of Aqp2 by this mutation resulted in a severe urine concentration defect.
cph
homozygotes demonstrated polydipsia and produced a copious amount of hypotonic urine. The urine concentration defect could not be corrected by [deamino-Cys
1
,
d
-Arg
8
]-vasopressin (DDAVP, a vasopressin analog), characteristic of nephrogenic diabetes insipidus. The nephrogenic diabetes insipidus symptoms and the absence of developmental defects in the pyeloureteral peristaltic machinery in the mutants before the onset of hydronephrosis suggest that the congenital obstructive nephropathy is most likely a result of the polyuria. This study has revealed the genetic basis for the classical
cph
mutation and has provided direct genetic evidence that S256 in Aqp2 is indispensable for the apical accumulation, but not the general glycosylation or membrane association, of Aqp2.
Epicatechins Purified from Green Tea (Camellia sinensis) Differentially Suppress Growth of Gender‐Dependent Human Cancer Cell Lines
Authors: Ravindranath Mepur H. , Saravanan Thiruverkadu S. , Monteclaro Clarence C. , Presser Naftali , Ye Xing , Selvan Senthamil R. , Brosman Stanley
Published: April 2006

The anticancer potential of catechins derived from green tea is not well understood, in part because catechin‐related growth suppression and/or apoptosis appears to vary with the type and stage of malignancy as well as with the type of catechin. This in vitro study examined the biological effects of epicatechin (EC), epigallocatechin (EGC), EC 3‐gallate (ECG) and EGC 3‐gallate (EGCG) in cell lines from human gender‐specific cancers. Cell lines developed from organ‐confined (HH870) and metastatic (DU145) prostate cancer, and from moderately (HH450) and poorly differentiated (HH639) epithelial ovarian cancer were grown with or without EC, EGC, ECG or EGCG. When untreated cells reached confluency, viability and doubling time were measured for treated and untreated cells. Whereas EC treatment reduced proliferation of HH639 cells by 50%, EGCG suppressed proliferation of all cell lines by 50%. ECG was even more potent: it inhibited DU145, HH870, HH450 and HH639 cells at concentrations of 24, 27, 29 and 30 µM, whereas EGCG inhibited DU145, HH870, HH450 and HH639 cells at concentrations 89, 45, 62 and 42 µM. When compared with EGCG, ECG more effectively suppresses the growth of prostate cancer and epithelial ovarian cancer cell lines derived from tumors of patients with different stages of disease.
Comparison of Mucosal Pressures Induced by Cuffs of Different Airway Devices
Authors: Ulrich-Pur Herbert , Hrska Franz , Krafft Peter , Friehs Helmut , Wulkersdorfer Beatrix , Köstler Wolfgang J. , Rabitsch Werner , Staudinger Thomas , Schuster Ernst , Frass Michael
Published: April 2006

Background

High pressures exerted by balloons and cuffs of conventional endotracheal tubes, the Combitube (Tyco Healthcare Nellcor Mallinckrodt, Pleasanton, CA), the EasyTube (Teleflex Ruesch, Kernen, Germany), the Laryngeal Mask Airway (LMA North America, San Diego, CA), the Intubating Laryngeal Mask Airway (Fastrach; LMA North America), the ProSeal (LMA North America), and the Laryngeal Tube (LT; VBM Medizintechnik, Sulz, Germany) may traumatize the pharyngeal mucosa. The aim of this study was to compare pressures exerted on the pharyngeal, tracheal, and esophageal mucosa by different devices designed for securing the patient's airways.

Methods

Nineteen fresh cadavers were included. To measure mucosal pressures, microchip sensors were fixed on the anterior, lateral, and posterior surfaces of the proximal balloon and the distal cuff of the investigated devices. Depending on the respective airway device, the cuff volume was increased in 10-ml increments at the proximal balloon starting from 0 to a maximum of 100 ml, and in 2-ml increments at the distal cuff starting from 0 up to 12 ml.

Results

Tracheal mucosal pressures were significantly higher using the Combitube compared with the endotracheal tube and the EasyTube. Maximal esophageal pressures were significantly higher using the EasyTube compared with the Combitube. Using cuff volumes according to the manufacturers' guidelines, we found the highest pharyngeal pressures with the Intubating Laryngeal Mask Airway versus all other devices. At maximal volumes, the Laryngeal Mask Airway, the Intubating Laryngeal Mask Airway, and the ProSeal induced significantly higher pharyngeal pressures compared with all other devices. Using a pharyngeal cuff volume of 40 ml, the Intubating Laryngeal Mask Airway followed by the Laryngeal Mask Airway exerted significantly higher pressures compared with the other devices.

Conclusions

Although some devices exhibit a somewhat higher mucosal pressure when compared with others, the authors believe that the observed differences of the cuff pressures do not suggest a clinically relevant danger, because the investigated devices, except the endotracheal tubes, are not intended for prolonged use.
Mild Hypercapnia Increases Subcutaneous and Colonic Oxygen Tension in Patients Given 80% Inspired Oxygen during Abdominal Surgery
Authors: Fleischmann Edith , Herbst Friedrich , Kugener André , Kabon Barbara , Niedermayr Monika , Sessler Daniel I. , Kurz Andrea
Published: April 2006

Background

Supplemental perioperative oxygen increases tissue oxygen tension and decreases incidence of wound infection in colorectal surgery patients. Mild intraoperative hypercapnia also increases subcutaneous tissue oxygen tension. However, the effect of hypercapnia in patients already receiving supplemental oxygen is unknown, as is the effect of mild hypercapnia on intestinal oxygenation in humans-although the intestines are presumably the tissue of interest for colon surgeries. The authors tested the hypothesis that mild intraoperative hypercapnia increases both subcutaneous tissue and intramural intestinal oxygen tension in patients given supplemental oxygen.

Methods

Patients undergoing elective colon resection were randomly assigned to normocapnia (n = 15, end-tidal carbon dioxide tension 35 mmHg) or mild hypercapnia (n = 15, end-tidal carbon dioxide tension 50 mmHg). Intraoperative inspired oxygen concentration was 80%. The authors measured subcutaneous tissue oxygen tension in the right upper arm and intramural oxygen tension in the left colon. Measurements were averaged over time within each patient and, subsequently, among patients. Data were compared with chi-square, unpaired t, or Mann-Whitney rank sum tests; P < 0.05 was significant.

Results

Morphometric characteristics and other possible confounding factors were similar in the groups. Intraoperative tissue oxygen tension in hypercapnic patients was significantly greater in the arm (mean +/- SD: 116 +/- 29 mmHg vs. 84 +/- 25 mmHg; P = 0.006) and colon (median [interquartile range]: 107 [81-129] vs. 53 [41-104] mmHg; P = 0.020).

Conclusions

During supplemental oxygen administration, mild intraoperative hypercapnia increased tissue oxygen tension in the arm and colon. Previous work suggests that improved tissue oxygenation will reduce infection risk via the proposed pathomechanism, although only an outcome study can confirm this.
Propofol-induced Activation of Protein Kinase C Isoforms in Adult Rat Ventricular Myocytes
Authors: Wickley Peter J. , Ding Xueqin , Murray Paul A. , Damron Derek S.
Published: April 2006

Background

Myocardial protection by anesthetics is known to involve activation of protein kinase C (PKC). The authors' objective was to identify the PKC isoforms activated by propofol in rat ventricular myocytes. They also assessed the intracellular location of individual PKC isoforms before and after treatment with propofol.

Methods

Freshly isolated ventricular myocytes were obtained from adult rat hearts. Immunoblot analysis of cardiomyocyte subcellular fractions was used to assess translocation of individual PKC isoforms before and after exposure to propofol. An enzyme-linked immunosorbent assay kit was used for measuring PKC activity. Immunocytochemistry and confocal microscopy were used to visualize the intracellular location of the individual PKC isoforms.

Results

Under baseline conditions, PKC-alpha, PKC-delta, and PKC-zeta were associated with both the cytosolic and membrane fractions, whereas PKC-epsilon was exclusively located in the cytosolic fraction. Propofol (10 microM) caused translocation of PKC-alpha, PKC-delta, PKC-epsilon, and PKC-zeta from cytosolic to membrane fraction and increased total PKC activity (211 +/- 17% of baseline; P = 0.003) in a dose-dependent manner. Immunocytochemical localization of the individual PKC isoforms demonstrated that propofol caused translocation of PKC-alpha to the intercalated discs and z-lines; PKC-delta to the perinuclear region; PKC-epsilon to sites associated with the z-lines, intercalated discs, and the sarcolemma; and PKC-zeta to the nucleus.

Conclusions

These results demonstrate that propofol causes an increase in PKC activity in rat ventricular myocytes. Propofol stimulates translocation of PKC-alpha, PKC-delta, PKC-epsilon, and PKC-zeta to distinct intracellular sites in cardiomyocytes. This may be a fundamentally important cellular mechanism of anesthesia-induced myocardial protection in the setting of ischemia-reperfusion injury.
The Common Inhalation Anesthetic Isoflurane Induces Apoptosis and Increases Amyloid β Protein Levels
Authors: Xie Zhongcong , Dong Yuanlin , Maeda Uta , Alfille Paul , Culley Deborah J. , Crosby Gregory , Tanzi Rudolph E.
Published: April 2006

Background

The common inhalation anesthetic isoflurane has previously been reported to enhance the aggregation and cytotoxicity of the Alzheimer disease-associated amyloid beta protein (Abeta), the principal peptide component of cerebral beta-amyloid deposits.

Methods

H4 human neuroglioma cells stably transfected to express human full-length wild-type amyloid precursor protein (APP) were exposed to 2% isoflurane for 6 h. The cells and conditioned media were harvested at the end of the treatment. Caspase-3 activation, processing of APP, cell viability, and Abeta levels were measured with quantitative Western blotting, cell viability kit, and enzyme-linked immunosorbent assay sandwich. The control condition consisted of 5% CO2 plus 21% O2 and balanced nitrogen, which did not affect caspase-3 activation, cell viability, APP processing, or Abeta generation.

Results

Two percent isoflurane caused apoptosis, altered processing of APP, and increased production of Abeta in H4 human neuroglioma cell lines. Isoflurane-induced apoptosis was independent of changes in Abeta and APP holoprotein levels. However, isoflurane-induced apoptosis was potentiated by increased levels of APP C-terminal fragments.

Conclusion

A clinically relevant concentration of isoflurane induces apoptosis, alters APP processing, and increases Abeta production in a human neuroglioma cell line. Because altered processing of APP leading to accumulation of Abeta is a key event in the pathogenesis of Alzheimer disease, these findings may have implications for use of this anesthetic agent in individuals with excessive levels of cerebral Abeta and elderly patients at increased risk for postoperative cognitive dysfunction.
Mechanisms Underlying the QT Interval–prolonging Effects of Sevoflurane and Its Interactions with Other QT-prolonging Drugs
Authors: Kang Jiesheng , Reynolds William P. , Chen Xiao-Liang , Ji Junzhi , Wang Hongge , Rampe David E.
Published: April 2006

Background

Sevoflurane prolongs ventricular repolarization in patients, but the mechanisms are not fully characterized. The effects of sevoflurane on many cloned human cardiac ion channels have not been studied, and the interactions between sevoflurane and other drugs that prolong cardiac repolarization have not been detailed.

Methods

The effects of sevoflurane on action potentials and L-type Ca channels in guinea pig myocytes were examined. Sevoflurane's effects on cloned human cardiac K channels and the cloned human cardiac Na channel were studied. The consequences of combining sevoflurane and the class III antiarrhythmic drugs sotalol or dofetilide on action potential duration were also examined.

Results

Sevoflurane produced an increase in action potential duration at concentrations of 0.3-1 mm. Contrary to most drugs that delay ventricular repolarization, sevoflurane was without effect on the human ether-a-go-go-related gene cardiac potassium channel but instead produced a reduction in KvLQT1/minK K channel currents and inhibited the Kv4.3 K channel by speeding its apparent rate of inactivation. Sevoflurane had little effect on Na and Ca channel currents at concentrations of 1 mm or less. When the authors coadministered sevoflurane with sotalol or dofetilide, synergistic effects on repolarization were observed, resulting in large increases in action potential duration (up to 66%).

Conclusion

Prolonged ventricular repolarization observed with administration of sevoflurane results from inhibition of KvLQT1/minK and Kv4.3 cardiac K channels. Combining sevoflurane with class III antiarrhythmic drugs results in supra-additive effects on action potential duration. The results indicate that sevoflurane, when administered with this class of drug, could result in excessive delays in ventricular repolarization. The results suggest the need for further clinical studies.
Orexins Increase Cortical Acetylcholine Release and Electroencephalographic Activation through Orexin-1 Receptor in the Rat Basal Forebrain during Isoflurane Anesthesia
Authors: Dong Hai-long , Fukuda Satoru , Murata Eri , Zhu Zhenghua , Higuchi Takashi
Published: April 2006

Background

Cholinergic arousal system plays an important role in the maintenance of consciousness. The authors investigated whether the intrabasalis injection of orexin-A or orexin-B and the electrically stimulated pedunculopontine tegmentum nuclei (PPTg: the origin of cholinergic ascending pathways) may alter acetylcholine efflux and electroencephalographic activity in the somatosensory cortex in relation to the orexinergic system in isoflurane-anesthetized rats.

Methods

Either orexin-A (10, 30, or 100 pmol) or orexin-B (10, 30, or 100 pmol) (n = 6 each) was injected into the basal forebrain while the electroencephalogram was measured during 1.0 minimum alveolar concentration (1.2%) isoflurane anesthesia. Injection of Ringer's solution was used as a control. The PPTg was electrically stimulated twice with the following conditions: 1-s stimulus train (0.2 ms, 100 Hz, 400 microA) per min for 20 min. Twenty minutes before the second PPTg stimulation, Ringer's solution or 20 microg SB334867, an orexin-1 receptor antagonist (n = 5 each) was injected into the basal forebrain.

Results

Injection of orexin-A (30 and 100 pmol) and orexin-B (100 pmol) significantly increased the acetylcholine efflux in the somatosensory cortex (P < 0.05). Injection of orexin-A (10, 30, 100 pmol) and orexin-B (30, 100 pmol) changed the burst and suppression patterns to arousal electroencephalogram. Compared with orexin-B, injection of a lower dose of orexin-A induced increase in the acetylcholine efflux and arousal electroencephalogram. SB334867 significantly attenuated the increases in the acetylcholine efflux and electroencephalographic activation evoked by PPTg stimulation.

Conclusion

The authors demonstrated that orexin-A was more potent than orexin-B in producing alteration of cholinergic basal forebrain neuronal activity and that the cortical activation induced by the PPTg stimulation against isoflurane anesthesia may be mediated through the orexin-1 receptors in the basal forebrain.
A Multicenter Dose-escalation Study of the Analgesic and Adverse Effects of an Oral Cannabis Extract (Cannador) for Postoperative Pain Management
Authors: Holdcroft Anita , Maze Mervyn , Doré Caroline , Tebbs Susan , Thompson Simon
Published: April 2006

Background

Cannabinoids have dose-related antinociceptive effects in animals. This clinical study aimed to investigate whether a single oral dose of cannabis plant extract (Cannador; Institute for Clinical Research, IKF, Berlin, Germany) could provide pain relief with minimal side effects for postoperative pain.

Methods

Patients (aged 18-75 yr) were recruited and consented before surgery if patient-controlled analgesia was planned for provision of postoperative pain relief. Each patient received a single dose of 5, 10, or 15 mg Cannador if he or she had at least moderate pain after stopping patient-controlled analgesia. Starting with 5 mg, dose escalation was based on the number of patients requesting rescue analgesia and adverse effects. Pain relief, pain intensity, and side effects were recorded over 6 h and analyzed using tests for trend with dose.

Results

Rescue analgesia was requested by all 11 patients (100%) receiving 5 mg, 15 of 30 patient (50%) receiving 10 mg, and 6 of 24 patients (25%) receiving 15 mg Cannador (log rank test for trend in time to rescue analgesia with dose P < 0.001). There were also significant trends across the escalating dose groups for decreasing pain intensity at rest (P = 0.01), increasing sedation (P = 0.03), and more adverse events (P = 0.002). The number needed to treat to prevent one rescue analgesia request for the 10-mg and 15-mg doses, relative to 5 mg, were 2.0 (95% confidence interval, 1.5-3.1) and 1.3 (95% confidence interval, 1.1-1.7), respectively. The study was terminated because of a serious vasovagal adverse event in a patient receiving 15 mg.

Conclusion

These significant dose-related improvements in rescue analgesia requirements in the 10 mg and 15 mg groups provide a number needed to treat that is equivalent to many routinely used analgesics without frequent adverse effects.
Efficacy of Single-dose, Multilevel Paravertebral Nerve Blockade for Analgesia after Thoracoscopic Procedures
Authors: Hill Steven E. , Keller Rebecca A. , Stafford-Smith Mark , Grichnik Katherine , White William D. , D'Amico Thomas A. , Newman Mark F.
Published: April 2006

Background

Although video-assisted thoracoscopic surgery for pulmonary resection is increasingly chosen over thoracotomy, the optimal analgesia regimen for thoracoscopy is unknown. The purpose of this trial was to compare the efficacy of analgesia from preoperative bupivacaine paravertebral nerve blockade with that from placebo injections.

Methods

Eighty adult patients undergoing unilateral thoracoscopic procedures were enrolled in a prospective, double-blinded, randomized clinical trial of preoperative, multilevel, single-dose paravertebral nerve blockade. Patients received six paravertebral injections with 5 ml of either 0.5% bupivacaine with 0.0005% epinephrine (treated, n = 40) or preservative-free saline (control, n = 40). Cumulative weight-adjusted intraoperative fentanyl and postoperative patient-controlled morphine usage, visual analog pain scores, and spirometry were used to compare efficacy of analgesia between groups.

Results

The treated group received significantly less intraoperative fentanyl compared with the control group (P = 0.003) and had a 31% smaller cumulative patient-controlled morphine dose (P = 0.03) in the 6 h after block placement. Within 6 h, treated patients also reported lower maximum pain scores (P = 0.02) and demonstrated less pain score variability (P = 0.01). No statistically significant difference in cumulative morphine usage existed at 12 or 18 h after block placement. No significant difference in spirometry, cortisol levels, or cytokine production was found between treatments.

Conclusions

Single-dose paravertebral nerve blockade with bupivacaine is effective in reducing pain after thoracoscopic surgery, but only during the first 6 h after nerve blockade. Because of the limited duration of effect with currently available local anesthetic agents, the current data suggest that, at present, this technique is not indicated in the setting of thoracoscopic surgery.
Comparison of crystal structures of human androgen receptor ligand‐binding domain complexed with various agonists reveals molecular determinants responsible for binding affinity
Authors: Pereira de Jésus‐Tran Karine , Côté Pierre‐Luc , Cantin Line , Blanchet Jonathan , Labrie Fernand , Breton Rock
Published: April 2006

Androgens exert their effects by binding to the highly specific androgen receptor (AR). In addition to natural potent androgens, AR binds a variety of synthetic agonist or antagonist molecules with different affinities. To identify molecular determinants responsible for this selectivity, we have determined the crystal structure of the human androgen receptor ligand‐binding domain (hARLBD) in complex with two natural androgens, testosterone (Testo) and dihydrotestosterone (DHT), and with an androgenic steroid used in sport doping, tetrahydrogestrinone (THG), at 1.64, 1.90, and 1.75 Å resolution, respectively. Comparison of these structures first highlights the flexibility of several residues buried in the ligand‐binding pocket that can accommodate a variety of ligand structures. As expected, the ligand structure itself (dimension, presence, and position of unsaturated bonds that influence the geometry of the steroidal nucleus or the electronic properties of the neighboring atoms, etc.) determines the number of interactions it can make with the hARLBD. Indeed, THG—which possesses the highest affinity—establishes more van der Waals contacts with the receptor than the other steroids, whereas the geometry of the atoms forming electrostatic interactions at both extremities of the steroid nucleus seems mainly responsible for the higher affinity measured experimentally for DHT over Testo. Moreover, estimation of the ligand–receptor interaction energy through modeling confirms that even minor modifications in ligand structure have a great impact on the strength of these interactions. Our crystallographic data combined with those obtained by modeling will be helpful in the design of novel molecules with stronger affinity for the AR.
Stoichiometry of lipid interactions with transmembrane proteins—Deduced from the 3D structures
Authors: Páli Tibor , Bashtovyy Denys , Marsh Derek
Published: April 2006

The stoichiometry of the first shell of lipids interacting with a transmembrane protein is defined operationally by the population of spin‐labeled lipid chains whose motion is restricted directly by the protein. Interaction stoichiometries have been determined experimentally for a wide range of α‐helical integral membrane proteins by using spin‐label ESR spectroscopy. Here, we determine the spatially defined number of first‐shell lipids at the hydrophobic perimeter of integral membrane proteins whose 3D structure has been determined by X‐ray crystallography and lipid–protein interactions characterized by spin‐labeling. Molecular modeling is used to build a single shell of lipids surrounding transmembrane structures derived from the PDB. Constrained energy optimization of the protein–lipid assemblies is performed by molecular mechanics. For relatively small proteins (up to 7–12 transmembrane helices), the geometrical first shell corresponds to that defined experimentally by perturbation of the lipid‐chain dynamics. For larger, multi‐subunit α‐helical proteins, the lipids perturbed directly by the protein may either exceed or be less in number than those that can be accommodated at the intramembranous perimeter. In these latter cases, the motionally restricted spin‐labeled lipids can be augmented by intercalation, or can correspond to a specific subpopulation at the protein interface, respectively. For monomeric β‐barrel proteins, the geometrical lipid stoichiometry corresponds to that determined from lipid mobility for a 22‐stranded barrel, but fewer lipids are motionally restricted than can be accommodated around an eight‐stranded barrel. Deviations from the geometrical first shell, in the β‐barrel case, are for the smaller protein with a highly curved barrel.
‘Indolent’ Waldenstrom's macroglobulinemia and a cerebrospinal fluid protein level of 16 g/L
Authors: Garderet Laurent , Baudel Jean Luc , Cervera Pascale , Azizi Louisa , Maury Eric , Guidet Bertrand , Gorin Norbert Claude , Offenstadt George
Published: April 2006

Abstract:  Waldenstrom's macroglobulinemia occasionally presents with neurological manifestations. Very rarely, it is due to a central nervous system localization, the so‐called Bing Neel Syndrome. We report a patient with an ‘indolent’ systemic disease and surprisingly a concomitant major CNS involvement.
Pharmacokinetics of nelfinavir in HIV‐1‐infected pregnant and nonpregnant women
Authors: Villani P. , Floridia M. , Pirillo M. F. , Cusato M. , Tamburrini E. , Cavaliere A. F. , Guaraldi G. , Vanzini C. , Molinari A. , Antoni A. degli , Regazzi M.
Published: April 2006

Aims

To compare steady‐state nelfinavir (NFV) pharmacokinetics in pregnant and nonpregnant HIV‐infected women.

Methods

Twenty‐five pregnant HIV‐infected women were selected from an ongoing observational study evaluating the pharmacokinetics of antiretroviral agents during pregnancy. Twenty of them were in the third and five in the second trimester. Data for the control group of 21 HIV‐infected nonpregnant women were taken from a previous multicentre pharmacokinetic trial. All the participating women achieved steady‐state plasma concentrations while on a highly active antiretroviral therapy (HAART) regimen including NFV (1250 mg bid) and two nucleoside reverse transcriptase inhibitors (NRTIs). Blood samples for NFV measurement were collected predose (Ctrough) and at 0.5, 1, 2, 3, 4, 5, 6, 8 and 12 h post dose.

Results

During the third trimester of pregnancy NFV AUC0−12 h median (range) values were 25.76 (12.61–42.74) µg h−1 ml−1, and were 32.49 (19.16–63.81) µg h−1 ml−1 in the control group [mean difference − 9.30 µg h−1 ml−1; 95% confidence interval (CI) −15.76, −2.83; P < 0.05). Median oral clearance (CL/F) was significantly higher in pregnant women than in the control group (48.5 l h−1, range 29.3–99.1 l h−1 vs. 38.5 l h−1, range 19.6–65.2 l h−1; mean difference 12.6 l h−1; 95% CI 3.3, 21.9) but the difference disappeared when CL/F was adjusted for body weight. Ctrough was significantly (P < 0.01) lower in pregnant compared with nonpregnant women (median 0.8 µg ml−1, range 0–2.6 µg ml−1 vs. 1.5 µg ml−1, range 0.5–4.9 µg ml−1; mean difference −1.0 µg ml−1; 95% CI −1.7, −0.31). The median elimination half‐life of NFV observed during pregnancy was 3.7 h (range 1.4–6.6 h), compared with 5.2 (range 3.1–10.1 h) in the control group (mean difference −1.7; 95% CI −2.8, −0.51).

Conclusions

Our results indicate that women in the later stages of pregnancy may be exposed to subtherapeutic concentrations of NFV. Thus, adjustments in drug dosage or frequency of administration may be required.
Immunobiology of Toll‐like receptors: Emerging trends
Authors: Pandey Saumya , Agrawal Devendra K
Published: April 2006

Toll‐like receptors (TLR), a family of evolutionarily conserved pathogen recognition receptors, play pivotal role as primary sensors of invading pathogens. TLR identify molecular motifs of infectious agents (pathogen associated molecular patterns) and elicit an effective defensive response against them. Mammalian TLR derive their name from the Drosophila Toll protein, with which they share sequence similarity. So far, expression of 10 TLR is known in humans. The adaptor proteins, myeloid differentiation factor 88 and Toll IL‐1 receptor (TIR) domain containing adaptor inducing IFN‐β (TRIF) are the key players in the TLR signalling cascade leading to the activation of nuclear factor (NF)‐κB and interferon regulatory factor‐3, respectively. Targeted manipulation of the TLR signalling pathway has immense therapeutic potential and may eventually prove to be a boon in the development of innovative treatments for diverse disease conditions. There is accumulating evidence that TLR agonists have tremendous potential as novel therapeutic targets. In this review, we have discussed the immunobiology of TLR and emphasize significant advances made within the ever‐expanding field of TLR that provide intriguing insights efficacious in unravelling the complexities associated with TLR.
Differential effects of insulin‐like growth factor‐1 and atheroma‐associated cytokines on cell proliferation and apoptosis in plaque smooth muscle cells of symptomatic and asymptomatic patients with carotid stenosis
Authors: Jia Guanghong , Cheng Gang , Agrawal Devendra K
Published: April 2006

Morbidity and mortality from atherosclerosis are associated with complicated atherosclerotic lesions due to plaque rupture, which is regulated by a balance between proliferation and apoptosis of vascular smooth muscle cells (VSMC). We examined insulin‐like growth factor‐1 (IGF‐1)‐induced survival of plaque VSMC from carotid endarterectomy specimens and investigated the underlying cellular mechanisms in the presence and absence of IL‐12 and IFN‐γ. Both IL‐12 and IFN‐γ were strongly expressed in symptomatic atherosclerotic plaques as compared with asymptomatic plaques. In asymptomatic plaque VSMC, IGF‐1 induced the survival and proliferation of VSMC and accelerated VSMC into S‐phase. IL‐12 or IFN‐γ inhibited proliferation and VSMC were arrested in the G0–G1 phase. IGF‐1 markedly inhibited the expression of p27kip and p21cip and significantly induced cyclin E and cyclin D. Both cytokines by themselves increased the expression of p27kip and p21cip and inhibited cyclin E and cyclin D. On the contrary, in symptomatic VSMC there was already increased apoptosis of VSMC and there was no significant effect of IGF‐1 or inflammatory cytokines on proliferation, apoptosis or the expression of p27kip and p21cip and cyclin D and E. These data suggest that IGF‐1 is more potent in inducing the survival of VSMC from the endarterectomy specimens of asymptomatic patients as compared to that of symptomatic subjects and cytokines associated with atheroma lesions decrease the activity of IGF‐1‐induced survival in the VSMC of asymptomatic plaques. The different expression and activity of cell cycle regulatory proteins could be responsible for apoptosis of VSMC and destabilization of atherosclerotic plaques.
Modulated microRNA expression during adult lifespan in Caenorhabditis elegans
Authors: Ibáñez‐Ventoso Carolina , Yang Maocheng , Guo Suzhen , Robins Harlan , Padgett Richard W. , Driscoll Monica
Published: April 2006

MicroRNAs (miRNAs) are small, abundant transcripts that can bind partially homologous target messages to inhibit their translation in animal cells. miRNAs have been shown to affect a broad spectrum of biological activities, including developmental fate determination, cell signaling and oncogenesis. Little is known, however, of miRNA contributions to aging. We examined the expression of 114 identified Caenorhabditis elegans miRNAs during the adult lifespan and find that 34 miRNAs exhibit changes in expression during adulthood (P≤ 0.05), 31 with more than a twofold level change. The majority of age‐regulated miRNAs decline in relative abundance as animals grow older. Expression profiles of developmental timing regulators lin‐4 and let‐7 miRNAs, as well as conserved muscle miRNA miR‐1, show regulation during adulthood. We also used bioinformatic approaches to predict miRNA targets encoded in the C. elegans genome and we highlight candidate miRNA‐regulated genes among C. elegans genes previously shown to affect longevity, genes encoding insulin‐like ligands, and genes preferentially expressed in C. elegans muscle. Our observations identify miRNAs as potential modulators of age‐related decline and suggest a general reduction of message‐specific translational inhibition during aging, a previously undescribed feature of C. elegans aging. Since many C. elegans age‐regulated miRNAs are conserved across species, our observations identify candidate age‐regulating miRNAs in both nematodes and humans.
RETRACTED: Melatonin inhibits the expression of the inducible isoform of nitric oxide synthase and nuclear factor kappa B activation in rat skeletal muscle
Authors: Alonso María , Collado Pilar S. , González‐Gallego Javier
Published: April 2006

Abstract:  This study investigated whether the induction of inducible nitric oxide synthase (iNOS) produced by acute exercise in rat skeletal muscle could be prevented by melatonin and whether iNOS down‐regulation was related to inhibition of nuclear factor kappaB (NF‐κB) activation. Male Wistar rats received melatonin i.p. at a dose of 1.0 mg/kg body weight 30 min before being exercised for 60 min on a treadmill at a speed of 25 m/min and a 10% slope. Exercise caused a significant induction of iNOS protein levels and a marked activation of NF‐κB that were significantly prevented in rats treated with melatonin. Exercise also resulted in increased IκB kinaseα (IKKα) and phosphorylated IκBα protein levels, whereas IκBα content decreased. These effects were blocked by melatonin administration. The increase in the muscle concentration of thiobarbituric acid reactive substances and in the oxidized/reduced glutathione ratio induced by exercise was partially prevented by melatonin. Our data indicate that melatonin has potent protective effects against damage caused by acute exercise in rat muscle, preventing oxidative stress, NF‐κB activation and iNOS over‐expression. These findings support the view that melatonin treatment, by abolishing the IKK/NF‐κB signal transduction pathway, might block the production of noxious mediators involved in the inflammatory process.
Genetic basis of Alzheimer's dementia: role of mtDNA mutations
Authors: Grazina M. , Pratas J. , Silva F. , Oliveira S. , Santana I. , Oliveira C.
Published: April 2006

Alzheimer's disease (AD) is the most common neurodegenerative disorder associated to dementia in late adulthood.Amyloid precursor protein,presenilin 1andpresenilin 2genes have been identified as causative genes for familial AD, whereas apolipoprotein Eɛ4allele has been associated to the risk for late onset AD. However, mutations on these genes do not explain the majority of cases. Mitochondrial respiratory chain (MRC) impairment has been detected in brain, muscle, fibroblasts and platelets of Alzheimer's patients, indicating a possible involvement of mitochondrial DNA (mtDNA) in the aetiology of the disease. Several reports have identified mtDNA mutations in Alzheimer's patients, suggesting the existence of related causal factors probably of mtDNA origin, thus pointing to the involvement of mtDNA in the risk contributing to dementia, but there is no consensual opinion in finding the cause for impairment. However, mtDNA mutations might modify age of onset, contributing to the neurodegenerative process, probably due to an impairment of MRC and/or translation mechanisms.
Chromatin remodeling and neuronal function: exciting links
Authors: Santos M. , Coelho P. A. , Maciel P.
Published: April 2006

Regulation of gene expression occurs at different levels, from DNA to protein, and through various mechanisms. One of them is modification of the chromatin structure, which is involved in the definition of transcriptional active and inactive regions of the chromosomes. These phenomena are associated with reversible chemical modifications of the genetic material rather than with variability within the DNA sequences inherited by the individual and are therefore called ‘epigenetic’ modifications. Ablation of the molecular players responsible for epigenetic modifications often gives rise to neurological and behavioral phenotypes in humans and in mouse models, suggesting a relevant function for chromatin remodeling in central nervous system function, particularly in the adaptive response of the brain to stimuli. We will discuss several human disorders that are due to altered epigenetic mechanisms, with special focus on Rett syndrome.
The microwave sky and the local Rees—Sciama effect
Authors: Rakić Aleksandar , Räsänen Syksy , Schwarz Dominik J.
Published: April 2006

The microwave sky shows unexpected features at the largest angular scales, among them the alignments of the dipole, quadrupole and octopole. Motivated by recent X-ray cluster studies, we investigate the possibility that local structures at the 100 h−1 Mpc scale could be responsible for such correlations. These structures give rise to a local Rees–Sciama contribution to the microwave sky that may amount to ΔT/T ∼ 10−5 at the largest angular scales. We model local structures by a spherical overdensity (Lemaître–Tolman–Bondi model) and assume that the Local Group is falling toward the centre. We superimpose the local Rees–Sciama effect on a statistically isotropic, Gaussian sky. As expected, we find alignments among low multipoles, but a closer look reveals that they do not agree with the type of correlations revealed by the data.
Polyamines Induce Resistance to Cationic Peptide, Aminoglycoside, and Quinolone Antibiotics in
Pseudomonas aeruginosa
PAO1
Authors: Kwon Dong H. , Lu Chung-Dar
Published: April 2006

Pseudomonas aeruginosa
, a gram-negative bacterium of human pathogens, is noted for its environmental versatility, enormous metabolic capacity, and resistance to antibiotics. Overexpression of the outer membrane protein OprH and increased resistance to polycationic peptide antibiotics (e.g., polymyxin B) mediated by the PhoPQ two-component system on induction of a putative lipopolysaccharide (LPS) modification operon (
PA3552-PA3559
) have been reported as part of the adaptive responses to magnesium limitation in
P. aeruginosa
. Induction of the
oprH-phoPQ
operon and the LPS modification operon by exogenous spermidine was revealed from GeneChip analysis during studies of polyamine metabolism and was confirmed by the
lacZ
fusions of affected promoters. From the results of MIC measurements, it was found that addition of spermidine or other polyamines to the growth medium increased the MIC values of multiple antibiotics, including polycationic antibiotics, aminoglycosides, quinolones, and fluorescent dyes. MIC values of these compounds in the transposon insertion mutants of
oprH
,
phoP
,
phoQ
, and
pmrB
were also determined in the presence and absence of spermidine. The results showed that the spermidine effect on cationic peptide antibiotic and quinolone resistance was diminished in the
phoP
mutant only. The spermidine effect on antibiotics was not influenced by magnesium concentrations, as demonstrated by MICs and
oprH
::
lacZ
fusion studies in the presence of 20 μM or 2 mM magnesium. Furthermore, in spermidine uptake mutants, MICs of cationic peptide antibiotics and fluorescent dyes, but not of aminoglycosides and quinolones, were increased by spermidine. These results suggested the presence of a complicated molecular mechanism for polyamine-mediated resistance to multiple antibiotics in
P. aeruginosa
.
Randomized, Double-Blind Study of Emtricitabine (FTC) plus Clevudine versus FTC Alone in Treatment of Chronic Hepatitis B
Authors: Lim Seng Gee , Krastev Zahary , Ng Tay Meng , Mechkov Grigor , Kotzev Iskren Andreev , Chan Sing , Mondou Elsa , Snow Andrea , Sorbel Jeff , Rousseau Franck
Published: April 2006

Emtricitabine (FTC) is approved for the treatment of human immunodeficiency virus. FTC and clevudine (CLV) have activity against hepatitis B virus (HBV). This report summarizes the results of a double-blind, multicenter study of patients with chronic hepatitis B who had completed a phase 3 study of FTC and were randomized 1:1 to 200 mg FTC once daily (QD) plus 10 mg CLV QD or 200 mg FTC QD plus placebo for 24 weeks with 24 weeks of follow-up. One hundred sixty-three patients were treated (82 with FTC plus CLV [FTC+CLV] and 81 with FTC); 72% were men, 53% were Asian, 47% were Caucasian, and 52% were hepatitis B e antigen positive, and the median baseline HBV DNA level was 6 log
10
copies/ml. After 24 weeks of treatment, 74% (FTC+CLV) versus 65% (FTC alone) had serum HBV DNA levels of <4,700 copies/ml (
P
= 0.114) (Digene HBV Hybrid Capture II assay). Twenty-four weeks posttreatment, the mean change in serum HBV DNA levels from baseline was −1.25 log
10
copies/ml (FTC+CLV), 40% had undetectable viremia (versus 23% for FTC alone), and 63% had normal alanine aminotransferase levels (versus 42% for FTC alone) (
P
≤ 0.025 for all endpoints). The safety profile was similar between arms during treatment, with less posttreatment exacerbation of hepatitis B in the combination arm. In summary, after 24 weeks of treatment, no significant difference between arms was observed, but there was a significantly greater virologic and biochemical response 24 weeks posttreatment in the FTC+CLV arm.
New Potential Antimalarial Agents: Therapeutic-Index Evaluation of Pyrroloquinazolinediamine and Its Prodrugs in a Rat Model of Severe Malaria
Authors: Xie Lisa H. , Li Qigui , Lin Ai J. , Smith Kirsten , Zhang Jing , Skillman Donald S.
Published: April 2006

Tetra-acetamide pyrroloquinazolinediamine (PQD-A4) and bis-ethylcarbamyl pyrroloquinazolinediamine (PQD-BE) are new derivatives of pyrroloquinazolinediamine (PQD) and are being investigated as potential chemotherapeutic agents for the treatment of malaria. Comparative studies to assess the therapeutic indices of PQD-A4, PQD-BE, and PQD were conducted in
Plasmodium berghei
-infected rats following daily intragastric dosing for three consecutive days. Artesunate (AS), a standard drug for treatment of severe malaria, was used as a comparator. The minimum doses required to clear malaria parasitemia were 156 μmol/kg of body weight for AS and 2.4 μmol/kg for PQD, PQD-4A, and PQD-BE. The maximum tolerated dose (MTD) of AS was 625 μmol/kg, and its therapeutic index was calculated to be 4. The MTDs of PQD-A4, PQD-BE, and PQD were found to be 190, 77, and 24 μmol/kg, respectively, yielding therapeutic indices of 80, 32, and 10, respectively. Although PQD-A4 and PQD-BE are only half as potent as PQD based on their curative effects, the two new derivatives, PQD-4A and PQD-BE, are 8.0-fold and 3.2-fold safer, respectively, than their parent compound when they are dosed for three consecutive days. Oral PQD-A4 and PQD-BE are 44 to 70 times more potent on an mg basis than intravenous AS. As assessed from the therapeutic index over 3 days, PQD-A4, PQD-BE, and PQD administered orally are 20.0, 8.0, and 2.5 times safer than AS given intravenously. The results indicate that PQD-4A is a promising candidate for antimalarial treatment.
Pharmacokinetics of Telbivudine in Subjects with Various Degrees of Hepatic Impairment
Authors: Zhou Xiao-Jian , Marbury Thomas C. , Alcorn Harry W. , Smith William B. , Dubuc Patrick Gloria , Chao George C. , Brown Nathaniel A.
Published: April 2006

This study evaluated the effect of hepatic impairment on the pharmacokinetics of telbivudine, an investigational nucleoside antiviral for the treatment of chronic hepatitis B virus infection. Twenty-four subjects were assigned to four hepatic function groups (normal function and mild, moderate, and severe impairment, with six subjects in each group) on the basis of Child-Pugh scores. The subjects were administered a single oral dose of 600 mg telbivudine, and blood samples were collected over a 48-h interval for pharmacokinetic analyses. Telbivudine was well tolerated by all subjects. Telbivudine plasma concentration-time profiles were similar across the four hepatic function groups. The principal pharmacokinetic parameters of drug exposure, i.e., the maximum plasma concentration and area under the drug concentration-time curve, were comparable between subjects with various degrees of hepatic impairment and those with normal hepatic function. Results from this single-dose pharmacokinetic assessment therefore provide a pharmacologic rationale for further evaluation of the safety and efficacy of telbivudine in hepatitis B virus-infected patients with decompensated liver diseases.