bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional Organization of Visual Cortex in the Prosimian Bush Baby Revealed by Optical Imaging of Intrinsic Signals
Authors: Xu Xiangmin , Bosking William H. , White Leonard E. , Fitzpatrick David , Casagrande Vivien A.
Published: July 2005

Cells in primary visual cortex (V1) of primates and carnivores respond most strongly to a visual stimulus presented to one eye, in a particular visual field location, and at a particular orientation. Each of these stimulus attributes is mapped across the cortical surface, and, in macaque monkeys and cats, strong geometrical relationships exist between these feature maps. In macaque V1 and V2, correlations between feature maps and cytochrome oxidase (CO)-rich modules have also been observed. To see if such relationships reflect a conserved principle of V1 functional architecture among primate species, we examined these maps in the prosimian bush baby, a species that has been proposed to represent the ancestral primate organization. We found that the layout of individual feature maps in bush baby V1 is similar to that of other primates, but we found an entirely different organization of orientation preference in bush baby V2 compared with that reported in simian primates. Another striking distinction between bush baby and simian species is that we observed no strong relationships among maps of orientation, ocular dominance, and CO blobs in V1. Thus our findings suggest that precise relationships between feature maps are not a common element of the functional organization in all primates and that such relationships are not necessary for achieving basic coverage of stimulus feature combinations. In addition, our results suggest that specific relationships between feature maps in V1, and the subdivision of V2 into functional compartments, may have arisen comparatively late in the evolution of primates.
Enhanced resistance to fatigue and altered calcium handling properties of sarcalumenin knockout mice
Authors: Zhao Xiaoli , Yoshida Morikatsu , Brotto Leticia , Takeshima Hiroshi , Weisleder Noah , Hirata Yutaka , Nosek Thomas M. , Ma Jianjie , Brotto Marco
Published: July 2005

Sarcalumenin is a Ca2+-binding protein located in the sarcoplasmic reticulum of striated muscle cells, the physiological function of which has not been fully determined yet. Using sarcalumenin knockout ( sar−/−) mice, we showed that sar ablation altered store-operated Ca2+entry (SOCE) and enhanced muscle fatigue resistance. Sar−/−mice fatigued less with treadmill exercise, and intact isolated soleus and extensor digitorum longus muscles from sar−/−mice were more resistant to intermittent fatiguing stimulation than those from wild-type mice. Enhanced SOCE was observed in the sar−/−muscles. Biochemical analysis revealed that sar−/−muscles contained significantly elevated expression of mitsugumin 29 (MG29), a synaptophysin-related membrane protein located in the triad junction of skeletal muscle. Because the ablation of mg29 has been shown to cause increased fatigability and dysfunction of SOCE, the enhanced SOCE activity seen in sar−/−muscle may be correlated with the increased expression of MG29. Our data suggest that systemic ablation of sarcalumenin caused enhanced resistance to muscle fatigue by compensatory changes in Ca2+regulatory proteins that effect SOCE.
Liposomes and Niosomes as Topical Drug Delivery Systems
Authors: Choi M.J. , Maibach H.I.
Published: July 2005

The skin acts as a major target as well as a principle barrier for topical/transdermal (TT) drug delivery. The stratum corneum plays a crucial role in barrier function for TT drug delivery. Despite major research and development efforts in TT systems and the advantages of these routes, low stratum corneum permeability limits the usefulness of topical drug delivery. To overcome this, methods have been assessed to increase permeation. One controversial method is the use of vesicular systems, such as liposomes and niosomes, whose effectiveness depends on their physicochemical properties. This review focuses on the effect of liposomes and niosomes on enhancing drug penetration, and defines the effect of composition, size and type of the vesicular system on TT delivery.
Bone Alkaline Phosphatase besides Intact Parathyroid Hormone in Hemodialysis Patients – Any Advantage?
Authors: Jorge Cristina , Gil Célia , Possante Marília , Silva Eugénia , Andrade Rui , Santos Nazaré , Cruz Ana , Teixeira Romeu , Ferreira Aníbal
Published: July 2005

Background/Aim: Bone alkaline phosphatase (bAP) is known to be an important biochemical marker of bone formation. Through the present study, we intended to find out whether there is any advantage in bAP determination, as a routine biochemical marker, besides intact parathyroid hormone (iPTH) in hemodialysis patients. Methods: In a population of 140 hemodialysis patients, bAP and iPTH were determined on four quarterly consecutive occasions. According to the values of iPTH (pg/ml) and bAP (ng/ml), patients were divided into four groups: group I: iPTH >200 and bAP >20, group II: iPTH >200 and bAP <20, group III: iPTH <200 and bAP <20 and group IV: iPTH <200 and bAP >20. Patients with higher serum phosphorus (P) (group A: p ≧7 mg/dl) were compared with those with lower serum P levels (group B: p <7 mg/dl). Results: The global correlation between iPTH and bAP (total evaluations, n = 503) was 0.32 (p < 0.001). Group IV patients tended to show a slight increase of serum aluminum (sAl) levels, which were 12.48 ± 5.35 µg/l higher than in the patients from group I (sAl = 9.97 ± 4.39 µg/l), group II (sAl = 10.86 ± 4.45 µg/l) or group III (sAl = 10.92 ± 3.92 µg/l). Significance values (Mann-Whitney) in each group, in comparison with group IV, were the following: group I: 0.004; group II: 0.062; group III: <0.001. Group A (n = 66) showed higher iPTH levels than group B (n = 430), although bAP and sAl were both similar in these two groups of patients (Mann-Whitney): iPTH (A) = 631.0 ± 487.7 vs. iPTH (B) = 253.3 ± 191.6, p < 0.001; bAP (A) = 22.9 ± 17.4 vs. bAP (B) = 20.4 ± 13.1, p = n.s.; sAl (A) = 10.2 ± 3.5 vs. sAl (B) = 10.8 ± 4.4, p = n.s. For similar Al and bAP values, group A showed a much stronger iPTH/bAP correlation than group B: r = 0.67 (p < 0.001) vs. r = 0.30 (p < 0.001), respectively. Conclusion: Although iPTH and bAP are frequently in agreement, it seems important to separate parathyroid activity given by iPTH, from bone remodelling reflected by bAP, in the presence of either a higher aluminum exposition or a well-controlled phosphatemia.
Assessing Suitability for Renal Donation: Can Equations Predicting Glomerular Filtration Rate Substitute for a Reference Method in the Indian Population?
Authors: Mahajan Sandeep , Mukhiya Gulshan K. , Singh Rajvir , Tiwari Suresh C. , Kalra Vikram , Guleria Sandeep , Agarwal Sanjay K. , Bhowmik Dipankar M. , Gupta Sanjay , Dash Suresh C.
Published: July 2005

Background: Accurate measurement of donor renal function has important long-term implications for both the donor and recipient. As the use of recommended filtration markers is limited by cumbersome and costly techniques, renal function is typically estimated using 24-hour urinary creatinine clearance (urine-CrCl). Prediction equations used for rapid bedside estimation of glomerular filtration rate (GFR) are simple and overcome the inaccuracies of urinary collection and, if validated, can expedite the donor workup besides reducing the cost. We assessed the suitability of urine-CrCl and prediction equations for evaluating potential Indian renal donors. Methods: 173 consecutive renal donors were enrolled. The predictive capabilities of the Cockcroft and Gault equation for creatinine clearance (CrCl) corrected for body surface area (CG-CrCl), CG-CrCl corrected for GFR (CG-GFR), MDRD-1, MDRD-2 and urine-CrCl were evaluated with 99mTc-diethylenetriaminepentaacetic acid (DTPA)-GFR as reference GFR. Results: The study population had a mean age of 44.1 years with 74% being females. Mean DTPA-GFR was 83.85 ml/min/1.73 m2. The median percent absolute difference was most with urine-CrCl and least with CG-GFR (21.84 and 13.82). The Pearson’s correlation varied from 0.08 to 0.26 (urine-CrCl and MDRD-1). The precision was most with MDRD-1 and least with urine-CrCl (0.07 and 0.01). The bias was least with CG-GFR and most with MDRD-2 (1.34 and 17.16). The number of subjects with predicted GFR values within 30% of DTPA was most with MDRD-1 (86%) and least with urine-CrCl (69%). The sensitivity for selecting a donor with a GFR of ≧80/ml/min/1.73 m2 was the most with CG-GFR (65.7%), while specificity was maximum with MDRD-2 (90.1%). Conclusion: Our results in potential Indian renal donors show that of all the prediction equations MDRD-1 is the most precise and accurate, while CG-GFR is the least biased. However, the poor correlation and level of error exhibited by these equations makes them suboptimal for donor evaluation.
Association between Neopterin and Carotid Intima-Media Thickness in Hemodialysis Patients
Authors: Erten Yasemin , Öztürk M.Akif , Oktar Suna , Pasaoglu Hatice , Reis Kadriye Altok , Derici İlver , Elbeg Sehri , Güz Galip , Bali Musa , Arinsoy Turgay , Sindel Sükrü
Published: July 2005

Background: Atherosclerotic lesions are heavily infiltrated by macrophages. Neopterin can be used as a marker of the activity of macrophages. Serum neopterin levels were elevated in non-renal patients with atherosclerosis. The intima-media thickness (IMT) of the carotid arteries in hemodialysis patients was significantly higher than in control subjects. In this study, we measured serum neopterin levels in hemodialysis patients and evaluated a possible correlation between neopterin levels and carotid IMT. Patients and Methods: Thirty-seven hemodialysis patients (26 male/11 female, mean age 47 ± 15 years) and 12 healthy subjects (8 male/4 female, mean age 43 ± 10 years) were included in this study. Serum neopterin levels were measured by using a commercial ELISA kit. Carotid IMT of the subjects were measured by high-resolution B-mode ultrasonography. Results: Carotid IMT values were 1.04 ± 0.29 and 0.77 ± 0.25 mm in hemodialysis patients and healthy controls, respectively (p < 0.01). Serum neopterin levels were 110.9 ± 19.1 and 3.8 ± 2.3 ng/ml in hemodialysis patients and healthy controls, respectively (p < 0.01). Serum neopterin levels were 103.2 ± 21.3 ng/ml in hemodialysis patients with IMT <1 mm (n = 15), and 116.7 ± 15.4 ng/ml in hemodialysis patients with IMT ≧1 mm (n = 22) (p < 0.05). Moreover, there was a significant correlation between serum neopterin levels and carotid IMT (p < 0.05, r = 0.363). Conclusion: Our findings suggest that neopterin could be associated with the severity of carotid atherosclerosis in hemodialysis patients.
Urinary Excretion of Vasoactive Factors following Contrast Media Exposure in Humans
Authors: Murakami Ryusuke , Kumazaki Tatsuo , Tajima Hiroyuki , Hayashi Hiromitsu , Kuwako Tomoyuki , Hakozaki Kenta , Kiriyama Tomonari
Published: July 2005

Background: Radiographic contrast media (CM) induce renal vasoconstriction and may initiate induced nephropathy. Endothelin (ET), a vasoconstrictor, and nitric oxide (NO), a vasodilator, which are synthesized in the kidney by the vascular endothelium as well as by tubular epithelial and glomerular mesangial cells, are key modulators of renal circulation after CM administration. Intravascular CM, in addition, induces pronounced diuresis and natriuresis. The aim of the present study was to evaluate and compare changes in endogenous vasoactive mediators and contrast-induced natriuresis after CM administration. Methods: Diagnostic angiographic procedures were performed in 14 patients (9 males and 5 females) using the non-ionic CM Iopamidol. Before and immediately after angiography, venous blood and urine samples were obtained. The urinary excretion of ET-1 and nitrates/nitrites (NOx), and the fractional excretion of sodium (FENa) were measured and analyzed. Results: The urinary excretion of both ET-1 and NOx increased significantly (p < 0.05) after angiography, and urinary ET-1 and NOx excretion was correlated with an increase in FENa (p < 0.05). Conclusion: Exposure to CM in humans is associated with an increase in urinary ET and NOx. The excretion of sodium following CM administration is associated with an increase in urinary ET and NOx. ET and NO might be important in the renal change in humans after CM administration.
Romberg and His Sign
Authors: Pearce J.M.S.
Published: July 2005

Moritz Heinrich Romberg (1795–1873) acquired much of the wisdom and attitudes prevailing in English medicine when in 1820 he translated into German, Andrew Marshall’s (1742–1813) The Morbid Anatomy of the Brain and Charles Bell’s The Nervous System of the Human Body. He revolutionised European neurology, publishing his Lehrbuch der Nervenkrankheiten des Menschen: the first systematic textbook in neurology. Romberg’s contribution to neurology, and his establishing tabes dorsalis as a distinctive disease were of crucial importance. Romberg’s sign, once synonymous with tabes dorsalis, became recognised as common to all proprioceptive disorders of the legs. His several major clinical contributions included: a classic description of achondroplasia, progressive facial hemiatrophy, and an unmistakable description of the pupils in tertiary syphilis before E.J. Remak and Argyll Robertson.
Prognosis following Postanoxic Myoclonus Status epilepticus
Authors: Hui Andrew C.F. , Cheng Claudia , Lam Anita , Mok Vincent , Joynt Gavin M.
Published: July 2005

Prediction of outcome after cardiac arrest has important ethical and socioeconomic implications. In general, delay in recovery of neurological function is associated with a worse prognosis. The presence of myoclonic seizures early after anoxia has been identified as a poor prognostic factor. We report a series of patients who developed postanoxic myoclonus status epilepticus (MSE), which was defined as continuous myoclonic seizure activity lasting 30 min or more. The results from 18 patients were retrieved, 11 men and 7 women, age ranging from 29 to 90 years. Myoclonus developed a mean of 11.7 h after cardiac arrest, persisting for a mean of 60.5 h. Sixteen (89%) died following MSE and the 2 survivors were highly dependent or remained in a persistent vegetative state, supporting the view that prognosis is poor in this condition.
Increased Antitumor Activity in Combined Treatment TS-1 and Docetaxel
Authors: Takahashi Ikuo , Emi Yasunori , Kakeji Yoshihiro , Uchida Junji , Fukushima Masakazu , Maehara Yoshihiko
Published: July 2005

As TS-1 and docetaxel (TXT) have different mechanisms of antitumor activity, the combination therapy is expected to have a higher response. Human gastric cancer xenografts SC-2, St-40, and SC-4 inoculated into nude rats were treated with TS-1 alone (TS-1 12 mg/kg/day, day 1–14), TXT alone (TXT 2 mg/kg/day, day 1 or day 8), and combination of both drugs. TS-1 alone showed antitumor activity against three tumors (growth inhibition rate (IR): SC-2 (38.6 and 40.5%), St-40 (54.5%), SC-4 (55.1%)). TXT was effective with minimal toxicity, especially on day 1 of administration (IR at day 1 administration: SC-2 (51.7%), St-40 (42.1%), SC-4 (46.3%)). In the combined TS-1 and TXT group, antitumor activity increased at day 1 and at day 8 TXT administration (IR at day 1 administration: SC-2 (68.4%), St-40 (72.5%), SC-4 (76.0%)). Weight loss of TS-1 and day 1 TXT administration was the same as that of TS-1 alone. TS-1 and TXT showed no pharmacokinetic interaction. Compared with 5-fluorouracil and cisplatin treatment, combined therapy with TS-1 and TXT showed the same antitumor activity and toxicity. Combined therapy with TS-1 and TXT showed enhanced antitumor activity compared with monotherapy of each drug. The outpatient-based treatment of this combination is worth investigating.
Immunochemotherapy with Rituximab, Vincristine and 5-Day Cyclophosphamide for Heavily Pretreated Follicular Lymphoma
Authors: Lazzarino Mario , Arcaini Luca , Orlandi Ester , Iacona Isabella , Bernasconi Paolo , Calatroni Silvia , Varettoni Marzia , Isa Luciano , Brusamolino Ercole , Bonfichi Maurizio , Passamonti Francesco , Burcheri Sara , Pascutto Cristiana , Regazzi Mario
Published: July 2005

Purpose: Therapeutic options for relapsed or refractory follicular lymphoma include combination chemotherapy, immunotherapy and, for selected patients, autotransplant. Because of the different mechanisms of action and non-overlapping toxicities, combination of rituximab with chemotherapy is a rational approach. Methods: 30 patients with follicular non-Hodgkin’s lymphoma with advanced-stage disease were treated with four cycles of immunochemotherapy with rituximab 375 mg/m2 on day 1, vincristine 2 mg i.v. on day 2 and cyclophosphamide 400 mg/m2 i.v. from days 2 to 6, repeated at 3-week intervals. All patients had received multiple lines of therapy (median 3); 9 (30%) had relapses (2 after high-dose therapy with autologous transplant), and 21 (70%) were in relapse and refractory to salvage treatment (with an anthracycline-containing regimen in 19). Results: Of 29 patients evaluable for response, 16 (55 %) obtained a complete response (CR) and 3 (10%) a partial response (PR), with an overall response rate of 65% (19/29); 10 patients (35%) achieved less than PR. The median event-free survival was 16.1 months for all patients, being 22.8 months for responders. After a median follow-up of 2 years from the start of therapy (range 6 months to 3.8 years), of 16 patients who achieved CR, 10 remain free of disease. Conclusion: The combination of rituximab with vincristine and 5-day cyclophosphamide is able to produce CR in patients with advanced follicular lymphoma, even in patients resistant to third-generation regimens. The regimen designed on the basis of pharmacokinetics of the chimeric antibody seemed important for the clinical efficacy of the combination.
An Early Phase II Study of S-1 in Patients with Metastatic Pancreatic Cancer
Authors: Ueno Hideki , Okusaka Takuji , Ikeda Masafumi , Takezako Yoriko , Morizane Chigusa
Published: July 2005

Objective: The aim of this study was to evaluate the efficacy and toxicity of S-1 in patients with metastatic pancreatic cancer. Methods: Patients were required to have a histological diagnosis of pancreatic adenocarcinoma with measurable metastatic lesions, and no prior chemotherapy. S-1 was administered orally at 40 mg/m2 twice daily for 28 days with a rest period of 14 days as one course. Administration was repeated until the appearance of disease progression or unacceptable toxicity. A pharmacokinetic study was done on day 1 in the initial 8 patients. Results: Nineteen patients were entered into this study. Four patients (21.1%) achieved a partial response with a 95% confidence interval of 6.1–45.6%. No change was noted in 10 patients (52.6%), and progressive disease in 5 patients (26.3%). The median survival time was 5.6 months with a one-year survival rate of 15.8%. The major adverse events were gastrointestinal toxicities such as nausea and anorexia, though most of them were tolerable and reversible. There were no large differences in the pharmacokinetic parameters of S-1 in patients with pancreatic cancer and those in patients with other cancers. Conclusion: S-1 is active and tolerated in patients with metastatic pancreatic cancer, which will be confirmed in the following large-scale phase II study.
Enhancement of Gemcitabine-Induced Apoptosis by Restoration of p53 Function in Human Pancreatic Tumors
Authors: Cascalló Manel , Calbó Joaquim , Capellà Gabriel , Fillat Cristina , Pastor-Anglada Marçal , Mazo Adela
Published: July 2005

Human pancreatic adenocarcinomas are highly resistant to conventional treatment modalities, specially to chemotherapy. Among the genes that modulate apoptosis in response to cytotoxic drugs, the role of p53 has been demonstrated to be of paramount importance. Moreover, p53 is mutated in close to 50% of pancreatic cancer, which renders attractive the reintroduction of this gene as a way to enhance the action of chemotherapeutics. In this paper, gemcitabine, the most effective drug for the treatment of pancreatic tumors, has been selected to develop a new combination approach in vivo based on an administration schedule previously optimized in vitro. In a human xenograft model, the sequential administration of gemcitabine and p53 resulted in potent tumor growth inhibition. Statistical differences were observed with respect to the growth of tumors receiving only gemcitabine or p53. Moreover, the chemosensitization observed in tumors treated with the combination gemcitabine-p53 correlated with differential histological features such as important increases in intratumoral fibrosis and apoptotic levels, when compared with unimodal treatments. Taken together, our data indicate that reintroduction of p53 function in human pancreatic tumors in vivo allows to restore molecular pathways improving the response to gemcitabine. It may constitute a useful step towards a better clinical treatment of patients harboring pancreatic cancer.
Outcome in Patients with Stroke Associated with Internal Carotid Artery Occlusion
Authors: Paciaroni Maurizio , Caso Valeria , Venti Michele , Milia Paolo , Kappelle L. Jaap , Silvestrelli Giorgio , Palmerini Francesco , Acciarresi Monica , Sebastianelli Michela , Agnelli Giancarlo
Published: July 2005

Background: The clinical outcome in patients with stroke associated with internal carotid artery (ICA) occlusion is poor, although a minority may recover without dependency. The purposes of this study were (1) to assess the predictive factors of adverse outcome in patients with stroke associated with an occlusion of the ICA and (2) to evaluate the rate of spontaneous recanalization of an occluded ICA. Methods: A total of 177 consecutive patients with first-ever ischemic stroke associated with ICA occlusion were prospectively examined from the Perugia Stroke Registry. Mean age was 71.4 ± 14.3 years; 53% were males. Multiple regression models were used to analyze predictors of mortality, dependency and ipsilateral stroke recurrence. Results: The most probable cause of occlusion was atherosclerosis in 65%, cardioembolism in 22%, dissection in 9% and other causes in 4%. Thirty percent of the patients died within 30 days. After a mean follow-up of 420 days (range 1–1,970 days), 45% of the patients had died and 75% had died or were disabled. Another 6% of the patients had a recurrent stroke ipsilateral to the occluded carotid artery. Age was the only predictor of 30-day mortality (77.7 ± 9.7 vs. 68.7 ± 15.2 years; p = 0.03) and of long-term mortality or disability (p < 0.003). Hypertension (OR 0.42; 95% CI 0.17–1.00; p = 0.05) was associated with a better outcome within 30 days from stroke onset. Previous ipsilateral transient ischemic attack (OR 0.24; 95% CI 0.06–0.89; p = 0.03) and hyperlipidemia (OR 0.38; 95% CI 0.15–0.99; p = 0.049) were predictors of a better outcome with respect to long-term mortality or disability. No predictors of ipsilateral stroke recurrence were found. One hundred and five out of 177 patients had adequate follow-up ultrasound data. After a mean follow-up of 1.8 years, 10 patients had recanalization of the occluded ICA (2/71 atherosclerosis, 3/19 cardioembolism and 5/15 dissection). Conclusions: After a mean follow-up of 1.2 years, 45% of the patients with stroke associated with ICA occlusion had died, while 75% had died or were functionally dependent. The presence of either previous ipsilateral transient ischemic attack, hypertension or hyperlipidemia was associated with a favorable outcome. Recanalization of an occluded ICA occurred in a minority of patients and it was associated with cardioembolism and with arterial dissection.
Preoperative Clinical Predictors of Response to Bilateral Subthalamic Stimulation in Patients with Parkinson’s Disease
Authors: Pahwa Rajesh , Wilkinson Steven B. , Overman John , Lyons Kelly E.
Published: July 2005

Background: Younger age and a response to a supra-threshold levodopa challenge have been reported to predict a favorable response to bilateral subthalamic nucleus (STN) stimulation. Objective: To identify and evaluate clinical factors which predict a positive outcome after bilateral STN stimulation in patients with Parkinson’s disease, using each patient’s typical doses of antiparkinsonian medication rather than a supra-threshold levodopa challenge. Methods: Forty-five Parkinson’s disease patients who underwent bilateral STN implantation were included in the study. There were 33 men and 12 women. Mean age and disease duration were 59.4 and 12.7 years, respectively. All patients underwent Unified Parkinson Disease Rating Scale (UPDRS) evaluations in the medication off and on states at baseline and postsurgically with stimulation on at 3, 6 and 12 months. The percentage improvement in UPDRS motor scores at baseline (medication off vs. on) was compared with the percentage improvement after stimulation optimization (baseline medication off vs. follow-up medication off/stimulation on). Results: The preoperative percentage improvement in UPDRS motor scores with antiparkinsonian medications was predictive of the postoperative percentage improvement in the UPDRS motor scores in the medication off/stimulation on state (r = 0.53, p < 0.001). However, preoperative UPDRS motor scores in the medication on state were more strongly correlated with the postsurgical effect of stimulation (r = 0.64, p < 0.001). The postoperative improvement in UPDRS motor scores with stimulation did not correlate with age, disease duration or time to programming optimization. Conclusions: The preoperative percentage improvement in UPDRS motor scores with antiparkinsonian medications and UPDRS motor score in the medication on state at baseline are the strongest clinical predictors of responsiveness to bilateral STN stimulation.
Unconventional Homologous Internalization of the Angiotensin II Type-1 Receptor Induced by G-Protein–Independent Signals
Authors: Feng Ying-Hong , Ding Yaxian , Ren Shuo , Zhou Lingyin , Xu Chuan , Karnik Sadashiva S.
Published: July 2005

Internalization of a G-protein–coupled receptor (GPCR) is essential to the desensitization, endocytosis, and signal transduction of the receptor. It has been the general view that conventional homologous internalization of a GPCR requires activation of the G-protein(s) coupled to the receptor. However, whether and how GPCR-mediated G-protein–independent signals trigger receptor internalization remains unknown, although G-protein–independent internalization has been reported. Here we show that an angiotensin II (Ang II) type-1 (AT
1
) receptor mutant incapable of activating any G-protein still undergoes normal internalization. Substitution of Asp
125
with Ala and Arg
126
with Leu at the highly conserved DRY motif of the AT
1
receptor disabled the ability of the receptor to activate G-proteins, as shown by various Ang II binding studies, GDP–GTP exchange, and inositol phosphate production assays. Surprisingly, the mutant internalized normally in the presence of Ang II and transactivated the epidermal growth factor receptor (EGFR). Similar to the wild-type receptor, overexpression of a dominant-negative K220R mutant GRK2 diminished the internalization of D125A-R126L but not the transactivation of EGFR. These data indicate that G-protein–independent specific signals may also trigger homologous internalizations of the AT
1
receptor through β-arrestin–dependent and -independent pathways, suggesting a possible mechanism for G-protein–independent activation of G-protein–coupled receptor kinases (GRKs). This may represent a general mechanism for triggering GPCR internalization.
Role of Natriuretic Peptide Receptor Guanylyl Cyclase-A in Myocardial Infarction Evaluated Using Genetically Engineered Mice
Authors: Nakanishi Michio , Saito Yoshihiko , Kishimoto Ichiro , Harada Masaki , Kuwahara Koichiro , Takahashi Nobuki , Kawakami Rika , Nakagawa Yasuaki , Tanimoto Keiji , Yasuno Shinji , Usami Satoru , Li Yuhao , Adachi Yuichiro , Fukamizu Akiyoshi , Garbers David L. , Nakao Kazuwa
Published: July 2005

Although plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are elevated early after myocardial infarction (MI), the significance is not fully understood. We therefore investigated the function of natriuretic peptides after induction of MI in knockout (KO) mice lacking the natriuretic peptide receptor guanylyl cyclase-A, the receptor for ANP and BNP. KO and wild-type (WT) mice were subjected to left coronary artery ligation and then followed up for 4 weeks. Irrespective of genotype, almost all deaths occurred within 1 week after induction of MI. KO mice showed significantly higher mortality because of a higher incidence of acute heart failure, which was associated with diminished water and sodium excretion and with higher cardiac levels of mRNAs encoding ANP, BNP, transforming growth factor-β1, and type I collagen. By 4 weeks after infarction, left ventricular remodeling, including myocardial hypertrophy and fibrosis, and impairment of left ventricular systolic function were significantly more severe in KO than WT mice. Notably, the enhanced myocardial fibrosis seen in KO mice was virtually absent in infarcted double-KO mice, lacking guanylyl cyclase-A and angiotensin II type 1a receptors, although there was no improvement in survival and no attenuation of cardiac hypertrophy. Thus, guanylyl cyclase-A activation by endogenous cardiac natriuretic peptides protects against acute heart failure and attenuates chronic cardiac remodeling after MI. These beneficial effects are mediated partly through inhibition of the renin-angiotensin system (RAS), although RAS-independent protective actions of guanylyl cyclase-A are also suggested.
Electrophysiological Properties of Rostral Ventrolateral Medulla Neurons in Angiotensin II 1a Receptor Knockout Mice
Authors: Matsuura Tomokazu , Kumagai Hiroo , Onimaru Hiroshi , Kawai Akira , Iigaya Kamon , Onami Toshiko , Sakata Katsufumi , Oshima Naoki , Sugaya Takeshi , Saruta Takao
Published: July 2005

We compared the electrophysiological properties of neurons in the rostral ventrolateral medulla of neonatal angiotensin II type 1a receptor knockout mice and wild-type mice with responses to angiotensin II, its type-1 receptor blocker candesartan, and its type-2 receptor blocker PD123319. Using the whole-cell patch-clamp technique, we examined the characteristics of rostral ventrolateral medulla neurons in brain stem-spinal cord preparations in which the sympathetic neuronal network is preserved. Baseline membrane potential and firing rate were almost similar between angiotensin II type 1a receptor knockout mice and wild-type mice. Superfusion with angiotensin II depolarized rostral ventrolateral medulla bulbospinal neurons in wild-type mice, whereas it hyperpolarized those in angiotensin II type 1a receptor knockout mice. Because pretreatment with candesartan significantly prevented the angiotensin II-induced depolarization in wild-type mice, the angiotensin II type 1 receptor is crucial for this depolarization. Superfusion with PD123319 depolarized rostral ventrolateral medulla bulbospinal neurons in angiotensin II type 1a receptor knockout mice. PD123319 prevented the angiotensin II-induced hyperpolarization in angiotensin II type 1a receptor knockout mice, and, rather, it induced depolarization. These results suggest that the angiotensin II type 2 receptor in rostral ventrolateral medulla plays an antagonistic role against the angiotensin II type 1a receptor in controlling the neuronal activity of rostral ventrolateral medulla.
North American Ginseng Exerts a Neutral Effect on Blood Pressure in Individuals With Hypertension
Authors: Stavro P. Mark , Woo Minna , Heim Tibor F. , Leiter Lawrence A. , Vuksan Vladimir
Published: July 2005

An early observational study suggested that ginseng could elevate blood pressure. This caused concern because 4.5% of American adults use ginseng, with a popular choice being North American ginseng. To date, North American ginseng lacks hemodynamic evaluation; therefore, we conducted a randomized, double-blinded, controlled trial to investigate its effect on blood pressure in 16 hypertensive individuals (mean±SD age 61.1±8.1 years; systolic/diastolic blood pressure 132.4±12.8/83.3±8.1 mm Hg; 13 on antihypertensives). We used 6 batches of North American ginseng root that varied in quality and ginsenoside content, representing the spectrum of this ginseng on the market. On 8 mornings, each participant was fitted with an ambulatory blood pressure monitor, which measured blood pressure during a 30-minute baseline period. Each participant then consumed in a randomized and double-blind fashion 3 g of encapsulated treatment: placebo (on 2 mornings) or powdered North American ginseng (on 6 mornings). After treatment, blood pressure was measured every 10 minutes for 160 minutes, and its change at each post-treatment time point relative to baseline was determined per individual and averaged, and the mean was obtained for the overall 160-minute period. None of the North American ginsengs or their mean differed from placebo in their effect on overall (160 minutes) mean blood pressure change. None affected blood pressure versus placebo at the 10-minute intervals; but their mean versus placebo increased systolic and diastolic blood pressure at 140 and 160 minutes, respectively, and lowered diastolic blood pressure at 100 minutes. The findings together suggested that North American ginseng exerts a neutral acute effect on blood pressure in hypertensive individuals.
A New Kindred With Pseudohypoaldosteronism Type II and a Novel Mutation (564D>H) in the Acidic Motif of the WNK4 Gene
Authors: Golbang Amir P. , Murthy Meena , Hamad Abbas , Liu Che-Hsiung , Cope Georgina , Van’t Hoff William , Cuthbert Alan , O’Shaughnessy Kevin M.
Published: July 2005

We identified a new kindred with the familial syndrome of hypertension and hyperkalemia (pseudohypoaldosteronism type II or Gordon’s syndrome) containing an affected father and son. Mutation analysis confirmed a single heterozygous G to C substitution within exon 7 (1690G>C) that causes a missense mutation within the acidic motif of WNK4 (564D>H). We confirmed the function of this novel mutation by coexpressing it in
Xenopus
oocytes with either the NaCl cotransporter (NCCT) or the inwardly rectifying K-channel (ROMK). Wild-type WNK4 inhibits
22
Na
+
flux in
Xenopus
oocytes expressing NCCT by ≈90% (
P
<0.001), whereas the 564D>H mutant had no significantly inhibitory effect on flux through NCCT. In oocytes expressing ROMK, wild-type WNK4 produced >50% inhibition of steady-state current through ROMK at a +20-mV holding potential (
P
<0.001). The 564D>H mutant produced further inhibition with steady-state currents to some 60% to 70% of those seen with the wild-type WNK4. Using fluorescent-tagged NCCT (enhanced cyan fluorescent protein–NCCT) and ROMK (enhanced green fluorescent protein–ROMK) to quantify the expression of the proteins in the oocyte membrane, it appears that the functional effects of the 564D>H mutation can be explained by alteration in the surface expression of NCCT and ROMK. Compared with wild-type WNK4, WNK4 564D>H causes increased cell surface expression of NCCT but reduced expression of ROMK. This work confirms that the novel missense mutation in WNK4, 564D>H, is functionally active and highlights further how switching charge on a single residue in the acid motif of WNK4 affects its interaction with the thiazide-sensitive target NCCT and the potassium channel ROMK.
Genetic Deletion of the p66
Shc
Adaptor Protein Protects From Angiotensin II–Induced Myocardial Damage
Authors: Graiani Gallia , Lagrasta Costanza , Migliaccio Enrica , Spillmann Frank , Meloni Marco , Madeddu Paolo , Quaini Federico , Padura Ines Martin , Lanfrancone Luisa , Pelicci PierGiuseppe , Emanueli Costanza
Published: July 2005

Angiotensin II (Ang II), acting through its G protein–coupled AT
1
receptor (AT
1
), contributes to the precocious heart senescence typical of patients with hypertension, atherosclerosis, and diabetes. AT
1
was suggested to transactivate an intracellular signaling controlled by growth factors and their tyrosin-kinase receptors. In cultured vascular smooth muscle cells, this downstream mechanism comprises the p66
Shc
adaptor protein, previously recognized to play a role in vascular cell senescence and death. The aim of the present study was 2-fold: (1) to characterize the cardiovascular phenotype of
p66

Shc

knockout mice (
p66

Shc

−/−
), and (2) to test the novel hypothesis that disrupting the
p66

Shc

might protect the heart from the damaging action of elevated Ang II levels. Compared with wild-type littermates (
p66

Shc

+/+
),
p66

Shc

−/−
showed similar blood pressure, heart rate, and left ventricular wall thickness. However, cardiomyocyte number was increased in mutant animals, indicating a condition of myocardial hyperplasia. In
p66

Shc

+/+
, infusion of a sub-pressor dose of Ang II (300 nmol/kg body weight [BW] daily for 28 days) caused left ventricular hypertrophy and apoptotic death of cardiomyocytes and endothelial cells. In contrast,
p66

Shc

−/−
were resistant to the proapoptotic/hypertrophic action of Ang II. Consistently, in vitro experiments showed that Ang II causes apoptotic death of cardiomyocytes isolated from
p66

Shc

+/+
hearts to a greater extent as compared with
p66

Shc

−/−
cardiomyocytes. Our results indicate a fundamental role of p66
Shc
in Ang II–mediated myocardial remodeling. In perspective, p66
Shc
inhibition may be envisioned as a novel way to prevent the deleterious effects of Ang II on the heart.
Postprandial Myocardial Perfusion in Healthy Subjects and in Type 2 Diabetic Patients
Authors: Scognamiglio Roldano , Negut Christian , De Kreutzenberg Saula Vigili , Tiengo Antonio , Avogaro Angelo
Published: July 2005

Background—

In diabetic patients, postprandial hyperglycemia is a more powerful risk factor for cardiovascular disease than fasting hyperglycemia itself. A negative influence of acute hyperglycemia on systemic endothelial function (brachial artery) has been shown. However, myocardial perfusion during postprandial hyperglycemia has not been investigated.

Methods and Results—

We evaluated the effects of a standardized mixed meal on myocardial perfusion in 20 healthy subjects and 20 consecutive patients with type 2 diabetes mellitus without macrovascular or microvascular complications. Myocardial perfusion was assessed in fasting and postprandial states by myocardial contrast echocardiography. Fasting myocardial flow velocity (β, 0.65±0.27 versus 0.67±0.24;
P
=NS), myocardial blood volume (MBV; 8.3±1.2 versus 8.4±2;
P
=NS), and myocardial blood flow (5.4±1.5 versus 5.6±2;
P
=NS) did not differ between control subjects and diabetic patients. In the postprandial state, β (0.67±0.24 versus 0.92±0.35;
P
<0.01), MBV (8.4±2 versus 10.9±2.7;
P
<0.01), and myocardial blood flow (5.6±2 versus 9.9±2.8;
P
<0.01) increased significantly in control subjects. In diabetic patients, β increased (0.65±0.27 versus 0.8±0.24;
P
<0.01) but MBV (8.3±1.2 versus 4.3±1.3;
P
<0.01) and myocardial blood flow (5.4±1.5 versus 3.4±0.9;
P
<0.01) decreased significantly. Changes in MBV (expressed as [(MBV
postprandial
−MBV
fasting
)/MBV
fasting
]×100) were significantly correlated with postprandial glycemia levels in diabetic patients.

Conclusions—

Postprandial hyperglycemia determines myocardial perfusion defects in type 2 diabetic patients. They are secondary to deterioration in microvascular function causing a decrease in MBV. In diabetic patients without microvascular or macrovascular complications, postprandial myocardial perfusion defects may represent an early marker of the atherogenic process in the coronary circulation; hence, its reversal constitutes a potential goal of treatment.
Hereditary Hemochromatosis and Risk of Ischemic Heart Disease
Authors: Ellervik Christina , Tybjærg-Hansen Anne , Grande Peer , Appleyard Merete , Nordestgaard Børge G.
Published: July 2005

Background—

We tested the hypothesis that the hereditary hemochromatosis genotypes C282Y/C282Y, C282Y/H63D, or C282Y/wild-type are risk factors for ischemic heart disease (IHD) and myocardial infarction (MI).

Methods and Results—

We performed a prospective study of 9178 individuals from the Danish general population followed up for 24 years, during which 1035 and 511 developed IHD and MI, respectively, and a case-control study of 2441 and 1113 IHD and MI cases versus 8080 controls. C282Y/C282Y, C282Y/H63D, and C282Y/wild-type versus wild-type/wild-type individuals were not associated with increased risk of IHD or MI in prospective studies, overall or stratified by gender. We had 90% power to detect a hazard ratio for IHD of 3.4 for C282Y/C282Y, 1.9 for C282Y/H63D, and 1.3 for C282Y/wild-type versus wild-type/wild-type. Furthermore, these genotypes were not associated with increased risk of IHD or MI in case-control studies, overall or stratified by gender. We had 90% power to detect an odds ratio for IHD of 3.6 for C282Y/C282Y, 1.8 for C282Y/H63D, and 1.3 for C282Y/wild-type versus wild-type/wild-type.

Conclusions—

In these studies, hereditary hemochromatosis C282Y/C282Y, C282Y/H63D, and C282Y/wild-type genotypes were not associated with IHD or MI; however, the study lacked the power to exclude the possibility that C282Y/C282Y and C282Y/H63D individuals have a modestly increased risk of IHD or MI.
Organization of Myocardial Activation During Ventricular Fibrillation After Myocardial Infarction
Authors: Thomas Stuart P. , Thiagalingam Aravinda , Wallace Elisabeth , Kovoor Pramesh , Ross David L.
Published: July 2005

Background—

Studies of ventricular fibrillation (VF) in small mammals have revealed localized sustained stationary reentry. However, studies in large mammals with surface mapping techniques have demonstrated only relatively short-lived rotors. The purpose of this study was to identify whether sustained high-frequency activation with low beat-to-beat variability was present at intramural sites in a postinfarct ovine model of VF.

Methods and Results—

VF was induced in 12 sheep 77±40 days after anterior myocardial infarction. Electrical activation was recorded with 20 multielectrode transmural plunge needles. Unipolar electrogram frequency content and local cycle duration variability were studied in 30-second recordings beginning 5 seconds after the onset of VF. Higher mean beat frequency was associated with lower SD of the cycle duration intervals (
r
=−0.91,
P
<0.001). The mean beat frequency and the SD of cycle duration intervals of the highest-frequency electrode were 8.8±2.0 Hz and 17±11 ms. In 3 cases, a region with regular activation throughout the recording was identified (SD of the cycle duration interval, 6.0±0.7 ms). Two of these sites and 67% of all sites with low local cycle duration variability were intramural. They occurred within regions with a high dominant frequency as determined by fast Fourier transform of the unipolar electrogram.

Conclusions—

Regions with the highest frequency of activation during VF were always associated with a low local cycle duration variability and usually intramural in this chronic infarct model. In a minority of cases, a region of stable, rapid, and very regular activation could be identified. These findings support the hypothesis that relatively stable periodic sources form a component of the mechanism of VF in this model.
Mapping of Familial Thoracic Aortic Aneurysm/Dissection With Patent Ductus Arteriosus to 16p12.2–p13.13
Authors: Van Kien Philippe Khau , Mathieu Flavie , Zhu Limin , Lalande Alain , Betard Christine , Lathrop Mark , Brunotte François , Wolf Jean-Eric , Jeunemaitre Xavier
Published: July 2005

Background—

Three loci have been shown to be responsible for nonsyndromic familial thoracic aortic aneurysms (TAAs) and aortic dissections (ADs). We recently described a large family in which TAA/AD associates with patent ductus arteriosus (PDA) and provided genetic arguments for a unique pathophysiological entity.

Methods and Results—

Genome-wide scan was performed in 40 subjects belonging to 3 generations in this large pedigree. Using the 7 TAA/AD cases as affected, we observed positive 2-point LOD scores on adjacent markers at chromosome 16p, with a maximum LOD score value of 2.73 at θ=0, a value that increased to 3.56 when 5 PDA cases were included. Multipoint linkage analysis yielded a maximum LOD score of 4.14 in the vicinity of marker
D16S3103
. Fine mapping allowed the observation of recombinant haplotypes that delimited a critical 20-cM interval at 16p12.2-p13.13. Automatic determination of aortic compliance with cine MRI showed that all subjects bearing the disease haplotype, even asymptomatic, displayed a very low level of aortic compliance and distensibility. Aortic stiffness was strongly associated with disease haplotype with a marked effect of age, indicating subclinical and early manifestation of the disease.

Conclusions—

Genetic analysis of this family identified a unique locus responsible for both TAA/AD and PDA at chromosome 16p12.2-p13.13 with aortic stiffness as an early hallmark of the disease. TAA/AD with PDA is a new monogenic entity among the genetically heterogeneous group of TAA/AD disease.
Differential Response of Delayed Healing and Persistent Inflammation at Sites of Overlapping Sirolimus- or Paclitaxel-Eluting Stents
Authors: Finn Aloke V. , Kolodgie Frank D. , Harnek Jan , Guerrero L.J. , Acampado Eduardo , Tefera Kirubel , Skorija Kristi , Weber Deena K. , Gold Herman K. , Virmani Renu
Published: July 2005

Background—

Although effective coverage of challenging coronary lesions has warranted the use of overlapping drug-eluting stents, the histopathological response to stent overlap is unknown.

Methods and Results—

The arterial reaction to overlapping Cypher or Taxus drug-eluting stents was examined in rabbits with bare metal stents, BxVelocity or Express, serving as controls. Single iliac artery balloon injury was followed by placement of 2 overlapping 3.0-mm-diameter drug-eluting stents or bare metal stents in 60 animals (mean length of overlap, 9.8±3.6 mm). Stented arteries were harvested at 28 and 90 days for histology. Overlapped segments exhibited delayed healing compared with proximal and distal nonoverlapping sites at 28 days. Overlapped segments in Taxus stents induced significantly more luminal heterophils/eosinophils and fibrin deposition than Cypher; peristrut giant cell infiltration, however, was more frequent in the latter. Overlapping bare metal stents also showed mild delayed healing compared with nonoverlapped segments, but not to the same extent as drug-eluting stents. Although neointimal thickness within the overlap was similar in 28- and 90-day Cypher stents, there was a significant increase with Taxus (
P
=0.03).

Conclusions—

Compared with bare metal stents, drug-eluting stents further delay arterial healing and promote inflammation at sites of overlap. Taxus stents induced greater fibrin deposition, medial cell loss, heterophils/eosinophils, and late neointimal hyperplasia. Patients receiving overlapping drug-eluting stents need more frequent follow-up than patients with nonoverlapping stents.