bluuebunny/crossref_metadata_2025 huggingface dataset:
THE ADOPTION OF ADVANCED MANUFACTURING TECHNOLOGY AND INNOVATION STRATEGY IN SMALL FIRMS
Authors: HEWITT-DUNDAS NOLA
Published: March 2004

The properties inherent in Advanced Manufacturing Technology (AMT) create new opportunities for firms, and in particular small firms. The capability of this technology to modify production specifications quickly and accurately means that firms can customize their products and attain economies of scope based on low volume and low cost production. While traditionally technology has been perceived merely as a tool in implementing business strategy, this paper suggests that AMT has the potential to directly affect a firm's innovation strategy. To date, however, empirical analysis to examine the technology-strategy relationship has not been forthcoming. Through empirical analysis this paper focuses on the relationship between the adoption of AMT and one element of firm's strategy choice, that is, their innovation strategy. This relationship is examined in the context of firm's market and industry structure and internal non-technological resource capabilities.
PROFIT AND RISK SHARING IN A VIRTUAL ENTERPRISE
Authors: KARJALAINEN JOUKO , HAAHTELA TERO , MALINEN PEKKA , SALMINEN VESA
Published: March 2004

Organizations are increasing the use of partnerships but improved models addressing the sharing of profits and risks are needed to foster innovations in networked new product development. We have used a case study approach to explore the implementation of profit- and risk-sharing mechanisms in a virtual enterprise. Lack of a shared vision may have been the most important cause for the early decomposition of the virtual enterprise. Therefore, the trust did not start to accumulate during the cooperation. This would have been imperative for the implementation of profit sharing mechanisms, because risk attitudes seemed to favor hierarchical rewarding mechanisms.
BEST PRACTICES FOR R&D PROJECT LEADERS: LESSONS FROM THIRTY YEARS OF LEADERSHIP RESEARCH
Authors: ELKINS TERI J. , KELLER ROBERT T.
Published: March 2004

We have generated six best practice lessons for R&D project leaders from the past 30 years of research. These lessons take into account the situation in the project team, advocate activities by the leader outside the project team, and encourage him/her to provide a vision of the project's importance. Furthermore, the lessons note the significance of developing a climate of innovation and relationships of trust and openness. Leadership differences for scientists and for engineers are discussed. Our lessons recognize the growing importance of the project leader's role for R&D effectiveness.
ROAM — THE RESEARCH OPPORTUNITY ASSESSMENT MODEL FOR TARGETED INNOVATION
Authors: DONATELLO JAMES M. , SAWYER JOHN E.
Published: March 2004

Knowledge-driven companies are facing financial and competitive pressures that make them increasingly difficult to allocate the kinds of financial resources to research as they have in the past. For this reason, corporate scientists, research managers and business managers must understand both the financial and knowledge returns associated with the research they conduct so that they can best direct and allocate resources to research that provides both financial returns and establishes the knowledge basis for future discovery and innovation. We present a model for assessing research opportunities both from the standpoint of responding to market needs and pushing forward new knowledge development. We illustrate the use of this analytic model in both market pull and research push examples. We argue that both business and research managers in corporations can use this analytical discipline to better join the needs of business and the research divisions that support them.
THE USE OF PROCESSES AND METHODS IN NPD — A SURVEY OF SWEDISH INDUSTRY
Authors: RUNDQUIST JONAS , CHIBBA ARON
Published: March 2004

Research often suggests that formal New Product Development (NPD) processes increase the success rate of NPD projects in a firm. However, recent studies indicate a relatively low usage of formal NPD-processes. Very few studies of NPD practices have been carried out in contexts other than that of the US, thus it is of interest to explore whether or not important differences exist. The present study aims to identify the use of and practices within formal NPD-processes in Swedish manufacturing firms and to compare the results with a study conducted in a US context. The results indicate that differences exist in for example reward systems for NPD teams.
TECHNOLOGY AND CORPORATE GOVERNANCE — LESSONS LEARNT
Authors: BETZ FREDERICK
Published: March 2004

The commercial benefits of technological change arise only from the proper convergence of several factors — corporate governance, financial markets, tax policy, and technological innovation. We explore a case in the United States in the 1990s when these factors were improperly handled and created a financial bubble without economic advance. There must be together — a proper business climate, proper tax laws, proper corporate governance, proper investment in innovation, and proper science & technology infrastructures. Distortion of these factors fosters not economic growth but corporate fraud.
Hepatic glucose autoregulation: responses to small, non-insulin-induced changes in arterial glucose
Authors: Camacho Raul C. , Lacy D. Brooks , James Freyja D. , Coker Robert H. , Wasserman David H.
Published: April 2004

The purpose of this study was to determine whether the sedentary dog is able to autoregulate glucose production (Ra) in response to non-insulin-induced changes (<20 mg/dl) in arterial glucose. Dogs had catheters implanted >16 days before study. Protocols consisted of basal (−30 to 0 min) and bilateral renal arterial phloridzin infusion (0–180 min) periods. Somatostatin was infused, and glucagon and insulin were replaced to basal levels. In one protocol (Phl ± Glc), glucose was allowed to fall from t = 0–90 min. This was followed by a period when glucose was infused to restore euglycemia (90–150 min) and a period when glucose was allowed to fall again (150–180 min). In a second protocol (EC), glucose was infused to compensate for the renal glucose loss due to phloridzin and maintain euglycemia from t = 0–180 min. Arterial insulin, glucagon, cortisol, and catecholamines remained at basal in both protocols. In Phl ± Glc, glucose fell by ∼20 mg/dl by t = 90 min with phloridzin infusion. Radid not change from basal in Phl ± Glc despite the fall in glucose for the first 90 min. Rawas significantly suppressed with restoration of euglycemia from t = 90–150 min ( P < 0.05) and returned to basal when glucose was allowed to fall from t = 150–180 min. Radid not change from basal in EC. In conclusion, the liver autoregulates Rain response to small changes in glucose independently of changes in pancreatic hormones at rest. However, the liver of the resting dog is more sensitive to a small increment, rather than decrement, in arterial glucose.
Paradoxical decrease of mitochondrial DNA deletions in epithelial cells of active ulcerative colitis patients
Authors: Fukushima Kouhei , Fiocchi Claudio
Published: April 2004

Ulcerative colitis (UC) is a condition characterized by chronic inflammation targeted at the epithelial layer. In addition to being involved in immune phenomena, UC epithelial cells exhibit decreased oxidation of butyrate, downregulation of oxidative pathway regulatory genes, and overexpression of mitochondrial (mt) genes. We investigated whether these events, which translate an altered energy metabolism, are associated with an abnormal pattern of mtDNA deletions. Highly purified colonocytes were isolated from surgically resected control, involved and uninvolved inflammatory bowel disease mucosa. The frequency, type, and number of mtDNA deletions were assessed by PCR amplification, Southern blot analysis, and cloning and sequencing of amplified DNA fragments. The 4977 mtDNA deletion was less frequent in UC than control and Crohn's disease (CD) epithelium, regardless of patient age. Several other deletions were detected, but all were less common in UC than control and CD cells. The frequency, variety, and number of mtDNA deletions were invariably lower in colonocytes isolated from inflamed mucosa than in autologous cells from noninflamed mucosa. In conclusion, in the absence of inflammation, UC colonocytes exhibit an mtDNA deletion pattern similar to that of control cells, indicating a normal response to physiological levels of oxidative stress. In active inflammation, when oxidative stress increases, the frequency, variety, and number of mtDNA deletions decrease. Because comparable abnormalities are absent in active CD, the mtDNA deletion pattern of active UC suggests that colonocytes respond uniquely to inflammation-associated stress in this condition.
Soluble complement receptor 1 preserves endothelial barrier function and microcirculation in postischemic pancreatitis in the rat
Authors: von Dobschuetz E. , Bleiziffer O. , Pahernik S. , Dellian M. , Hoffmann T. , Messmer K.
Published: April 2004

Components of the activated complement cascade are considered to play a pivotal role in ischemia-reperfusion-induced organ injury. With the use of intravital epifluorescence microscopy, we investigated the effect of complement inhibition by the recombinant soluble complement receptor 1 (sCR1; TP10) on the effect of macromolecular microvascular permeability, functional capillary perfusion, and leukocyte endothelium interaction in postischemic pancreatitis. Anaesthetized Sprague-Dawley rats were subjected to 60 min of normothermic pancreatic ischemia induced by microclipping of the blood-supplying arteries of the organ. Rats who received sCR1 (15 mg/kg body wt iv; n = 7) during reperfusion showed a significant reduction of permeability (1.77 ± 1.34 × 10-8cm/s; n = 7) of tetramethylrhodamine isothiocyanate-labeled albumin injected 90 min after the onset of reperfusion compared with vehicletreated animals (6.95 ± 1.56 × 10-8cm/s; n = 7). At 120 min after the onset of reperfusion, the length of red blood cell-perfused capillaries (functional capillary density) was significantly improved (from 279 ± 15.7 to 330 ± 3.7 cm-1; n = 7) and the number of leukocytes adherent to postcapillary venules was significantly reduced (from 314 ± 87 to 163 ± 71 mm-2; n = 7) by sCR1 compared with vehicle treatment. Complement inhibition by sCR1 effectively ameliorates pancreatic ischemia-reperfusion-induced microcirculatory disturbances and might be considered for treatment of postischemic pancreatitis.
Identification of nonsulfated cholecystokinin-58 in canine intestinal extracts and its biological properties
Authors: Reeve Joseph R. , Liddle Rodger A. , McVey Douglas C. , Vigna Steven R. , Solomon Travis E. , Keire David A. , Rosenquist Grace , Shively John E. , Lee Terry D. , Chew Peter , Green Gary M. , Coskun Tamer
Published: April 2004

Nonsulfated CCK58[CCK58(ns)] has not been considered to be of biological importance because CCK58(ns) binds poorly to the CCKAreceptor and has only been identified once in intestinal extracts. In this work, a radioimmunoassay specific for the COOH-terminal region of gastrin and CCK (antibody 5135) was used to monitor the purification of CCK molecular forms from canine intestinal extracts. A minor immunoreactive peak was associated with a major absorbance peak during an ion-exchange, HPLC step. Characterization of this minor immunoreactive peak demonstrated that it was CCK58(ns). CCK58(ns) is 14% as immunoreactive as sulfated CCK8[CCK8(s)]. Amino acid analysis demonstrated that CCK58(ns) was present at 50% the amount of CCK58(s). In addition, we found that CCK58(ns) does not potently displace an125I-labeled CCK10analog from the CCKAreceptor in mouse pancreatic membranes and does not stimulate amylase release from isolated pancreatic acini, or stimulate pancreatic secretion in an anesthetized rat model. By contrast, CCK58(ns) does bind to CCKBreceptors and stimulates gastric acid secretion via this receptor. The presence of CCK58(ns) and its ability to selectively stimulate the CCKBreceptor without stimulation of the CCKAreceptor suggest that CCK58(ns) may have unique physiological properties, especially tissues where the nonsulfated peptide can act as a paracrine or neurocrine agent.
Inhaled nitric oxide attenuates pulmonary hypertension and improves lung growth in infant rats after neonatal treatment with a VEGF receptor inhibitor
Authors: Tang Jen-Ruey , Markham Neil E. , Lin Yuh-Jyh , McMurtry Ivan F. , Maxey Anne , Kinsella John P. , Abman Steven H.
Published: April 2004

VEGF plays a critical role during lung development and is decreased in human infants with bronchopulmonary dysplasia. Inhibition of VEGF receptors in the newborn rat decreases vascular growth and alveolarization and causes pulmonary hypertension (PH). Nitric oxide (NO) is a downstream mediator of VEGF, but whether the effects of impaired VEGF signaling are due to decreased NO production is unknown. Therefore, we sought to determine whether impaired VEGF signaling downregulates endothelial NO synthase (eNOS) expression in the developing lung and whether inhaled NO (iNO) decreases PH and improves lung growth after VEGF inhibition. Newborn rats received a single dose of SU-5416 (a VEGF receptor inhibitor) or vehicle by subcutaneous injection and were killed up to 3 wk of age for assessments of right ventricular hypertrophy (RVH), radial alveolar counts (RAC), lung eNOS protein, and NOx production in isolated perfused lungs (IPL). Neonatal treatment with SU-5416 increased RVH in infant rats and reduced RAC. Compared with controls, SU-5416 reduced lung eNOS protein expression by 89% at 5 days ( P < 0.01). IPL studies from day 14 rats demonstrated increased baseline pulmonary artery pressure and lower perfusate NOx concentration after SU-5416 treatment. Importantly, iNO treatment prevented the increase in RVH and improved RAC after SU-5416 treatment. We conclude that treatment of neonatal rats with SU-5416 downregulates lung eNOS expression and that iNO therapy decreases PH and improves lung growth after SU-5416 treatment. We speculate that decreased NO production contributes to PH and decreases distal lung growth caused by impaired VEGF signaling.
Renal ischemia induces tropomyosin dissociation-destabilizing microvilli microfilaments
Authors: Ashworth Sharon L. , Wean Sarah E. , Campos Silvia B. , Temm-Grove Constance J. , Southgate Erica L. , Vrhovski Bernadette , Gunning Peter , Weinberger Ron P. , Molitoris Bruce A.
Published: March 2004

Ischemic-induced cell injury results in rapid duration-dependent actin-depolymerizing factor (ADF)/cofilin-mediated disruption of the apical microvilli microfilament cores. Because intestinal microvillar microfilaments are bound and stabilized in the terminal web by the actin-binding protein tropomyosin, we questioned whether a protective effect of tropomyosin localization to the terminal web of the proximal tubule microfilament cores is disrupted during ischemic injury. With tropomyosin-specific antibodies, we examined rat cortical sections under physiological conditions and following ischemic injury by confocal microscopy. In addition, Western blot analysis of cortical extracts and urine was undertaken. Our studies demonstrated the presence of tropomyosin isoforms in the proximal tubule microvillar terminal web under physiological conditions and their dissociation in response to 25 min of ischemic injury. This correlated with the excretion of tropomyosin-containing plasma membrane vesicles in urine from ischemic rats. In addition, we noted increased tropomyosin Triton X-100 solubility following ischemia in cortical extracts. These studies suggest tropomyosin binds to and stabilizes the microvillar microfilament core in the terminal web under physiological conditions. With the onset of ischemic injury, we propose that tropomyosin dissociates from the microfilament core providing access to microfilaments in the terminal web for F-actin binding, severing and depolymerizing actions of ADF/cofilin proteins.
Poly(ADP-ribose) polymerase and renal hypothermic preservation injury
Authors: Mangino Martin J. , Ametani Mary , Szabó Csaba , Southard James H.
Published: March 2004

The nuclear enzyme poly(ADP-ribose) polymerase (PARP) has been implicated in ischemia-reperfusion injury in many tissues under normothermic conditions. The purpose of this study was to determine whether PARP contributes to mechanisms of the hypothermic ischemia-reperfusion injury that occurs when kidneys are cold stored for transplantation. Cortical tissue slice PARP enzyme activity rose significantly with prolonged cold storage and was dependent on both reperfusion and preservation quality. However, prior exposure to warm ischemia abrogated this increase. PARP protein increased with cold storage but was not dependent on reperfusion. PARP enzyme activity rose quickly after reperfusion in buffer and was not different when whole blood was used. Addition of exogenous hydrogen peroxide (3 mM) to normal renal slices significantly increased PARP activity over 4 h in the cortex but not in the medulla, but the medullary basal PARP synthesis rate was five times higher than that in the cortex. However, the reactive oxygen species (ROS) inhibitors catalase (2,000 U/ml), Trolox (200 μM), and DMSO (15 mM) did not reduce reperfusion-induced PARP activity in cold-stored cortical slices. Finally, PARP inhibitors potentiated preservation injury in isolated canine proximal renal tubules. In conclusion, canine renal PARP enzyme activity rises with prolonged cold storage after reperfusion and may play a protective rather than an injurious role in hypothermic preservation for transplantation. ROS are sufficient but not necessary to activate PARP under these conditions.
Renal expression of COX-2, ANG II, and AT1receptor in remnant kidney: strong renoprotection by therapy with losartan and a nonsteroidal anti-inflammatory
Authors: Gonçalves Anderson Ricardo Roman , Fujihara Clarice Kazue , Mattar Ana Lúcia , Malheiros Denise Maria Avancini Costa , Noronha I. L. , de Nucci Gilberto , Zatz Roberto
Published: March 2004

Chronic renal injury can be mediated by angiotensin II (ANG II) and prostanoids through hemodynamic and inflammatory mechanisms and attenuated by individual suppression of these mediators. In rats with ⅚ renal ablation (Nx), we investigated 1) the intrarenal distribution of COX-2, ANG II, and the AT1receptor (AT1R); 2) the renoprotective and antiinflammatory effects of an association between the AT1R blocker, losartan (Los), and the gastric sparing anti-inflammatory nitroflurbiprofen (NOF). Adult male Munich-Wistar rats underwent Nx or sham operation (S), remaining untreated for 30 days, after which renal structure was examined in 12 Nx rats (Nxpre). The remaining rats were followed during an additional 90 days, distributed among 4 treatment groups: NxV(vehicle), NxLos(Los), NxNOF(NOF), and NxLos/NOF(Los/NOF). Nxprerats exhibited marked albuminuria, hypertension, glomerulosclerosis, interstitial expansion, and macrophage infiltration, accompanied by abnormal glomerular, vascular, and interstitial COX-2 expression. ANG II appeared in interstitial cells, in contrast to S, in which ANG II was virtually confined to afferent arterioles. Intrarenal AT1R distribution shifted from mostly tubular in S to predominantly interstitial in Nxpre. All these changes were aggravated at 120 days and attenuated by Los and NOF monotherapies. Los/NOF treatment arrested renal structural injury and ANG II expression and reversed hypertension, albuminuria, and renal inflammation. In conclusion, abnormal expression of COX-2, ANG II, and AT1R may be key to development of renal injury in Nx. Concomitant COX-2 inhibition and AT1R blockade arrested renal injury and may represent a useful strategy in the treatment of chronic nephropathies.
Evidence for bradykinin as a stimulator of thirst
Authors: Cadnapaphornchai Melissa A. , Rogachev Boris , Summer Sandra N. , Chen Yung-Chang , Gera Lajos , Stewart John M. , Schrier Robert W.
Published: March 2004

Angiotensin-converting enzyme inhibition (ACEI) with captopril has been shown to increase water intake and urine output in rats, but the mechanism is unknown. ACEI impairs the conversion of ANG I to ANG II, a dipsogenic hormone, and impairs the degradation of bradykinin. The goal of this study was to examine the role of bradykinin in the polydipsia and polyuria associated with ACEI. Male Sprague-Dawley rats received captopril (CPT; 20 mg·kg-1·day-1) in ground chow for 48 h. Water intake, food intake, and urine output were monitored and compared with control rats (CTL), rats receiving captopril treatment with limited water intake (CPT-LIM), and rats receiving captopril treatment with ad libitum water intake plus 24-h treatment with the bradykinin antagonist B-9430 (CPT-BK1). CPT rats consumed significantly more water and produced more urine vs. CTL. Urine osmolality was significantly decreased in CPT rats vs. CTL. Inner medullary aquaporin-2 (AQP2) protein abundance was also markedly decreased in CPT rats vs. CTL. These findings were reversed in CPT-LIM rats, suggesting captopril-induced primary polydipsia. CPT-BKI rats demonstrated parameters no different from CTL despite ad libitum water intake. Mean arterial pressure and 24-h creatinine clearance did not differ among groups. We conclude that ACEI with captopril induces primary polydipsia despite impaired production of the dipsogen ANG II and that this primary increase in water intake is likely the cause of the decreased protein abundance of inner medullary AQP2. Furthermore, this dipsogenic effect was reversed by antagonism of bradykinin, thus implicating this hormone in thirst regulation in the rat.
Increased expression and apical targeting of renal ENaC subunits in puromycin aminonucleoside-induced nephrotic syndrome in rats
Authors: Kim Soo Wan , Wang Weidong , Nielsen Jakob , Praetorius Jeppe , Kwon Tae-Hwan , Knepper Mark A. , Frøkiær Jørgen , Nielsen Søren
Published: March 2004

Nephrotic syndrome is often accompanied by sodium retention and generalized edema. However, the molecular basis for the decreased renal sodium excretion remains undefined. We hypothesized that epithelial Na channel (ENaC) subunit dysregulation may be responsible for the increased sodium retention. An experimental group of rats was treated with puromycin aminonucleoside (PAN; 180 mg/kg iv), whereas the control group received only vehicle. After 7 days, PAN treatment induced significant proteinuria, hypoalbuminemia, decreased urinary sodium excretion, and extensive ascites. The protein abundance of α-ENaC and β-ENaC was increased in the inner stripe of the outer medulla (ISOM) and in the inner medulla (IM) but was not altered in the cortex. γ-ENaC abundance was increased in the cortex, ISOM, and IM. Immunoperoxidase brightfield- and laser-scanning confocal fluorescence microscopy demonstrated increased targeting of α-ENaC, β-ENaC, and γ-ENaC subunits to the apical plasma membrane in the distal convoluted tubule (DCT2), connecting tubule, and cortical and medullary collecting duct segments. Immunoelectron microscopy further revealed an increased labeling of α-ENaC in the apical plasma membrane of cortical collecting duct principal cells of PAN-treated rats, indicating enhanced apical targeting of α-ENaC subunits. In contrast, the protein abundances of Na+/H+exchanger type 3 (NHE3), Na+-K+-2Cl-cotransporter (BSC-1), and thiazide-sensitive Na+-Cl-cotransporter (TSC) were decreased. Moreover, the abundance of the α1-subunit of the Na-K-ATPase was decreased in the cortex and ISOM, but it remained unchanged in the IM. In conclusion, the increased or sustained expression of ENaC subunits combined with increased apical targeting in the DCT2, connecting tubule, and collecting duct are likely to play a role in the sodium retention associated with PAN-induced nephrotic syndrome. The decreased abundance of NHE3, BSC-1, TSC, and Na-K-ATPase may play a compensatory role to promote sodium excretion.
Protein tyrosine kinase is expressed and regulates ROMK1 location in the cortical collecting duct
Authors: Lin Dao-Hong , Sterling Hyacinth , Yang Baofeng , Hebert Steven C. , Giebisch Gerhard , Wang Wen-Hui
Published: March 2004

We previously demonstrated that dietary K intake regulates the expression of Src family PTK, which plays an important role in controlling the expression of ROMK1 in plasma membrane (Wei Y, Bloom P, Lin D-H, Gu RM, and Wang WH. Am J Physiol Renal Physiol 281: F206–F212, 2001). In the present study, we used the immunofluorescence staining technique to demonstrate the presence of c-Src, a member of Src family PTK, in the thick ascending limb (TAL) and collecting duct. Confocal microscopy shows that c-Src is highly expressed in the renal cortex and outer medulla. Moreover, c-Src and ROMK are coexpressed in the same nephron segment. Also, the positive staining of c-Src is visible in tubules stained with Tamm-Horsfall glycoprotein or aquaporin-2. This suggests that c-Src is present in the TAL, cortical collecting duct (CCD), and outer medullary collecting duct (OMCD). To study the role of PTK in the regulation of ROMK membrane expression in the TAL and CCD, we carried out immunocytochemical staining with ROMK antibody in the CCD or TAL from rats on either a high-K (HK) or K-deficient (KD) diet. A sharp membrane staining of ROMK can be observed in the TAL from rats on both HK and KD diets. However, a clear plasma membrane staining can be observed only in the CCD from rats on a HK diet but not from those on a KD diet. Treatment of the CCD from rats on a HK diet with phenylarsine oxide (PAO) decreases the positive staining in the plasma/subapical membrane and increases the ROMK staining in the intracellular compartment. However, PAO treatment did not significantly alter the staining pattern of ROMK in the TAL. Moreover, the biotinylation technique has also confirmed that neither herbimycin A nor PAO has significantly changed the biotin-labeled ROMK2 in HEK293 cells transfected with ROMK2 and c-Src. We conclude that c-Src is expressed in the TAL, CCD, and OMCD and that stimulation of PTK increases the ROMK channels in the intracellular compartment but decreases them in the apical/subapical membrane in the CCD.
Adipose differentiation-related protein and regulators of lipid homeostasis identified by gene expression profiling in the murinedb/dbdiabetic kidney
Authors: Mishra Rangnath , Emancipator Steven N. , Miller Casey , Kern Timothy , Simonson Michael S.
Published: March 2004

We investigated the molecular basis of progressive diabetic renal injury in db/db mice by profiling kidney gene expression. Using high-density microarrays, we identified 482 RNA transcripts differentially expressed in 8-wk db/db vs. nondiabetic db/m kidneys, a time characterized by hyperglycemia but by little renal histopathology. By 16 wk significant mesangial expansion had developed. Sixteen-week db/db kidneys differentially expressed 639 RNA transcripts. Diabetic kidneys specifically expressed several genes normally found in adipocytes, including adipocyte differentiation-regulated protein (ADRP; or adipophilin in humans). ADRP mRNA was specifically upregulated 5.4-fold in 16-wk db/db kidneys. This finding was confirmed at the protein level by Western blotting, and immunohistochemistry localized ADRP diffusely to tubular epithelium throughout the cortex. ADRP is a perilipin family protein that forms lipid storage vesicles and controls triglyceride utilization; we showed that accumulation of lipid storage droplets correlated with the magnitude and localization of ADRP in db/db kidneys. Other genes involved in lipid transport, oxidation, and storage were differentially regulated in db/db kidneys, and peroxisome proliferator-activated receptor-α (PPARα) has been shown to regulate their expression in adipocytes. In our experiments, PPARα mRNA was elevated in db/db diabetic kidneys, and PPARα protein was upregulated in glomeruli, cortical tubules, and renal arterial vessels of db/db mice. In conclusion, these studies furnish new RNA-based data for mechanistic investigation into renal injury in the diabetic kidney and identify a switch of kidney phenotype in favor of lipid accumulation in diabetic kidney.
Angiostatin and matrix metalloprotease expression following ischemic acute renal failure
Authors: Basile David P. , Fredrich Katherine , Weihrauch Dorothee , Hattan Naoichiro , Chilian William M.
Published: March 2004

Ischemic injury to the kidney results in blood vessel loss and predisposition to chronic renal disease. Angiostatin is a proteolytic cleavage product of plasminogen that inhibits angiogenesis, promotes apoptosis of endothelial cells, and disrupts capillary integrity. A combination of lysine-Sepharose enrichment followed by Western blotting was used to study the expression of angiostatin in response to the induction of ischemic renal injury. No angiostatin products were readily detectable in kidneys of sham-operated control rats. In contrast, both 38- and 50-kDa forms of angiostatin were dramatically enhanced in the first 3 days following 45-min ischemia-reperfusion injury. Renal angiostatin levels declined but remained detectable at late time points postrecovery (8–35 days postischemia). Angiostatin-like immunoreactivity was also elevated in the plasma and in urine for up to 35 days following injury. Lysine-Sepharose extracts of either kidney or urine inhibited vascular endothelial cell growth factor-induced proliferation of human aortic endothelial cells in vitro; an effect that was blocked by coincubation with an angiostatin antibody. RT-PCR verified that mRNA of the parent protein plasminogen was produced in the liver, but it was not present in either sham-operated or postischemic kidney. Matrix metalloproteinase (MMP)-2 and MMP-9, which may mediate angiostatin generation, were enhanced in postischemic kidney tissue and were localized to the renal tubules, interstitial cells, and the tubulo-interstitial space. These data indicate the possible local synthesis of angiostatin following acute renal failure (ARF) and suggest a possible role for MMPs in this activity. Renal angiostatin generation following ARF may modulate renal capillary density postischemia and thereby influence chronic renal function.
The basolateral expression of mUT-A3 in the mouse kidney
Authors: Stewart Gavin S. , Fenton Robert A. , Wang Weidong , Kwon Tae-Hwan , White Stanley J. , Collins Valerie M. , Cooper Gordon , Nielsen Søren , Smith Craig P.
Published: March 2004

Facilitative UT-A urea transporters play a central role in the urinary concentrating mechanism. There are three major UT-A isoforms found in the mouse kidney: mUT-A1, mUT-A2, and mUT-A3. The major aim of this study was to identify the location and function of mUT-A3. UT-A proteins were investigated using three novel mouse UT-A-targeted antibodies: ML446, MQ2, and ML194. ML446 detected mUT-A1 and mUT-A3. ML194 detected mUT-A1 and mUT-A2. Importantly, MQ2 was found to be selective for mUT-A3. MQ2 detected a 45- to 65-kDa signal in the mouse kidney inner medulla, which was deglycosylated to a 40-kDa protein band. Immunolocalization studies showed that mUT-A3 was strongly detected in the papillary tip, mainly in the basolateral regions of inner medullary collecting duct (IMCD) cells. Immunoblotting of subcellular fractions of inner medullary protein suggested that in mouse kidney mUT-A3 was present in plasma membranes. Consistent with this, immunoelectron microscopy demonstrated that mUT-A3 was predominantly localized at the basal plasma membrane domains of the IMCD cells in mouse kidney. Heterologous expression of mUT-A3-enhanced green fluorescent protein in Madin-Darby canine kidney cells showed that the protein localized to the basolateral membrane. In conclusion, our study indicates that mUT-A3 is a basolateral membrane transporter expressed in IMCD cells.
Kidneys sans glomeruli
Authors: Beyenbach Klaus W.
Published: March 2004

The evolution of the vertebrate kidney records three occasions, each separated by about 50 million years, when fish have abandoned glomeruli to produce urine by tubular mechanisms. The recurring dismissal of glomeruli suggests a mechanism of aglomerular urine formation intrinsic to renal tubules. Indeed, the transepithelial secretion of organic solutes and of inorganic solutes such as sulfate, phosphate, and magnesium can all drive secretory water flow in renal proximal tubules of fish. However, the secretion of NaCl via secondary active transport of Cl is the primary mover of secretory water flow in, surprisingly, proximal tubules of both glomerular and aglomerular fish. In filtering kidneys, the tubular secretion of solute and water is overshadowed by reabsorptive transport activities, but secretion progressively comes to light as glomerular filtration decreases. Thus the difference between glomerular and aglomerular urine formation is more a difference of degree than of kind. At low rates of glomerular filtration in seawater fish, NaCl-coupled water secretion serves to increase the renal excretory capacity by increasing the luminal volume into which waste, excess, and toxic solutes can be secreted. The reabsorption of NaCl and water in the distal nephron and urinary bladder concentrates unwanted solutes for excretion while minimizing renal water loss. In aglomerular fish, NaCl-coupled water secretion across proximal tubules replaces glomerular filtration to increase renal excretory capacity. A review of the literature suggests that tubular secretion of NaCl and water is an early function of the vertebrate proximal tubule that has been retained throughout evolution. Active transepithelial Cl secretion takes place in gall bladders studied as models of the mammalian proximal tubule and in proximal tubules of amphibians and apparently also of mammals. The tubular secretion of Cl is also observed in mammalian distal tubules. The evidence consistent with and for Cl secretion in, respectively, proximal and distal tubules of the mammalian kidney calls for a reexamination of basic assumptions in renal physiology that may lead to new opportunities for managing some forms of renal disease.
Organic anion transport in choroid plexus from wild-type and organic anion transporter 3 (Slc22a8)-null mice
Authors: Sykes Destiny , Sweet Douglas H. , Lowes Simon , Nigam Sanjay K. , Pritchard John B. , Miller David S.
Published: March 2004

The choroid plexus actively transports endogenous, xenobiotic, and therapeutic compounds from cerebrospinal fluid to blood, thereby limiting their exposure to the central nervous system (CNS). Establishing the mechanisms responsible for this transport is critical to our understanding of basic choroid plexus physiology and will likely impact drug targeting to the CNS. We recently generated an organic anion transporter 3- (Oat3)-null mouse, which exhibited loss of PAH, estrone sulfate, and taurocholate transport in kidney and of fluorescein (FL) transport in choroid plexus. Here, we measured the uptake of four Oat3 substrates by choroid plexus from wild-type and Oat3-null mice to establish 1) the contribution of Oat3 to the apical uptake of each substrate and 2) the Na dependence of transport by Oat3 in the intact tissue. Mediated transport of PAH and FL was essentially abolished in tissue from Oat3-null mice. In contrast, only a 33% reduction in estrone sulfate uptake was observed in tissue from Oat3-null mice and, surprisingly, no reduction in taurocholate uptake could be detected. For PAH, FL, and estrone sulfate, all Oat3-mediated transport was Na dependent. However, estrone sulfate and taurocholate also exhibited additional mediated and Na-dependent components of uptake that were not attributed to Oat3, demonstrating the complexity of organic anion transport in this tissue and the need for further examination of expressed transporters and their energetics.
Determinants of plasma water sodium concentration as reflected in the Edelman equation: role of osmotic and Gibbs-Donnan equilibrium
Authors: Nguyen Minhtri K. , Kurtz Ira
Published: March 2004

Edelman et al. have empirically shown that plasma water sodium concentration ([Na+]pw) is equal to 1.11(Nae + Ke)/TBW - 25.6 (Edelman IS, Leibman J, O'Meara MP, Birkenfeld LW. J Clin Invest 37: 1236–1256, 1958). However, the physiological significance of the slope and y-intercept in this equation has not been previously considered. Our analysis demonstrates that there are several clinically relevant parameters determining the magnitude of the y-intercept that independently alter [Na+]pw: 1) osmotically inactive exchangeable Na+ and K+; 2) plasma water K+ concentration; and 3) osmotically active non-Na+ and non-K+ osmoles. In addition, we demonstrate quantitatively the physiological significance of the slope in the Edelman equation and its role in modulating [Na+]pw. The slope of 1.11 in this equation which Edelman et al. determined empirically can be theoretically predicted by considering the combined effect of the osmotic coefficient of Na+ salts at physiological concentrations and Gibbs-Donnan equilibrium. In addition, our results demonstrate that the slope has an independent quantitative impact on the magnitude of the y-intercept in the Edelman equation. From a physiological standpoint, the components of both the slope and the y-intercept need to be addressed when considering the factors that modulate [Na+]pw.
Age-dependent regulation of vasopressin V1areceptors in preglomerular vessels from the spontaneously hypertensive rat
Authors: Vågnes Øyvind B. , Hansen Frank H. , Christiansen Rolf E. F. , Gjerstad Camilla , Iversen Bjarne M.
Published: March 2004

Experiments were performed to get insight into the role of AVP receptor V1aregulation with age, i.e., during development and maintenance of high blood pressure. Previous studies showed an increased gene expression and renal vascular response to AVP in young spontaneously hypertensive rats (SHR). The age regulation of the V1areceptor was examined in preglomerular vessels from 5-, 10-, 20-, and 70-wk-old SHR using normotensive Wistar-Kyoto rats (WKY) as controls. Real-time PCR and ligand binding were used for analysis of receptor expression, and the change in cytosolic calcium concentration during stimulation of isolated preglomerular vessels with AVP was studied. Studies showed an increase of the V1areceptor protein and mRNA from 5-and 10-wk-old SHR compared with vessels from 20- and 70-wk-old SHR. In 5-wk-old SHR receptor density was 84 ± 13 fmol/mg protein, and 38 ± 11 fmol/mg protein in 70-wk-old SHR ( P < 0.05). mRNA in the 5- and 70-wk-old SHR was 15,854 ± 629 and 3,181 ± 224 V1amRNA/108 18S ribosomal RNA, respectively ( P < 0.001). Values from WKY at all ages were similar to 20- and 70-wk-old SHR. During stimulation with AVP, the change in cytosolic calcium in vessels from 5-wk-old SHR increased 234 ± 59 nM, whereas the increase was 89 ± 9 nM in 70-wk-old SHR ( P = 0.03). These results indicate that the V1areceptor is increased at protein and mRNA level during development of hypertension in SHR but is normalized when hypertension is established.
Increased blood pressure in transgenic mice expressing both human renin and angiotensinogen in the renal proximal tubule
Authors: Lavoie Julie L. , Lake-Bruse Kristy D. , Sigmund Curt D.
Published: March 2004

The purpose of this study was to evaluate the physiological significance of a tissue renin-angiotensin system in the proximal tubule of the kidney. To accomplish this, we produced mice that express human renin (hREN) under the control of the kidney androgen-regulated promoter (KAP), which is androgen responsive. One of the lines expressed the hREN transgene primarily in the kidney. Renal expression of the transgene was undetectable in females but could be induced by testosterone treatment. Because the renin-angiotensin system is species specific, we bred KAP2-hREN mice with the mice expressing human angiotensinogen under the same promoter (KAP-hAGT) to produce offspring that expressed both transgenes. We measured mean arterial blood pressure (MAP) in the carotid artery of double-transgenic and control mice using radiotelemetry. Double-transgenic female mice had a normal baseline MAP (116 ± 4 mmHg, n = 8), which increased by 15 mmHg after 2 wk of testosterone treatment, and returned to baseline after elimination of the testosterone pellet. The change in arterial pressure paralleled the change in plasma testosterone. There was no MAP change in testosterone-treated control littermates. We conclude that dual production of renin and angiotensinogen in the renal proximal tubule can result in a systemic increase in arterial pressure. These data support a role for a tissue-specific renin-angiotensin system in the renal proximal tubule that contributes to the regulation of systemic blood pressure.
NBCn1 is a basolateral \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Na}^{+}\mathrm{-HCO}_{3}^{-}\) \end{document} cotransporter in rat kidney inner medullary collecting ducts
Authors: Praetorius Jeppe , Kim Young-Hee , Bouzinova Elena V. , Frische Sebastian , Rojek Aleksandra , Aalkjær Christian , Nielsen Søren
Published: March 2004

Primary cultures of rat inner medullary collecting duct (IMCD) cells Na+dependently import [Formula: see text] across the basolateral membrane through an undefined transport protein. We used RT-PCR, immunoblotting, and immunohistochemistry to identify candidate proteins for this basolateral [Formula: see text] cotransport. The mRNA encoding the electroneutral [Formula: see text] cotransporter NBCn1 was detected as the only [Formula: see text] cotransporter in the rat inner medulla (IM) among the five characterized Na+-dependent [Formula: see text] transporters. The mRNA of a yet uncharacterized transporter-like protein, BTR1, was also present in the IM, but its expression in microdissected tubules seemed restricted to the thin limbs of Henle's loop. Immunoblotting confirmed the presence of NBCn1 as an ∼180-kDa protein of the rat IM. Anti-NBCn1 immunolabeling was confined to the basolateral plasma membrane domain of IMCD cells in the papillary two-thirds of the IM. Consistent with the presence of NBCn1, IMCD cells possessed stilbene-insensitive, Na+- and [Formula: see text]-dependent pH recovery after acidification, as assessed by fluorescence microscopy using a pH-sensitive intracellular dye. In furosemide-induced alkalotic rats, NBCn1 protein abundance was decreased in both the IM and inner stripe of outer medulla (ISOM) as determined by immunoblotting and immunohistochemistry. In contrast, NBCn1 abundance in the IM and ISOM was unchanged in NaHCO3-loaded animals, and the NBCn1 abundance increased only in the ISOM after NH4Cl loading. In conclusion, NBCn1 is a basolateral [Formula: see text] cotransporter of IMCD cells and is differentially regulated in IMCD and medullary thick ascending limb.
Deconvolution of confocal images of dihydropyridine and ryanodine receptors in developing cardiomyocytes
Authors: Sedarat Franklin , Lin Eric , Moore Edwin D.W. , Tibbits Glen F.
Published: April 2004

Colocalization of dihydropyridine (DHPR) and ryanodine (RyR) receptors, a key determinant of Ca2+-induced Ca2+release, was previously estimated in 3-, 6-, 10-, and 20-day-old rabbit ventricular myocytes by immunocytochemistry and confocal microscopy. We now report on the effects of deconvolution (using a maximum-likelihood estimation algorithm) on the calculation of colocalization indexes. Clusters of DHPR and RyR can be accurately represented as point sources of fluorescence, which enables a model of their relative distributions to be constructed using images of point spread functions to simulate their fluorescence inside a cell. This model was used to investigate the effects of deconvolution on colocalization as a function of separation distance. Deconvolution resulted in significant improvements in both axial and transverse resolutions, producing significant increases in clarity. Comparisons of intensity profiles (full-width half-maximum) pre- and postdeconvolution showed decreased dispersion of the fluorescent signal and a corresponding decrease in false colocalization as determined by fluorescence modeling. This hypothesis was extended to physiological data previously collected. The number of colocalized voxels was quantified after deconvolution, and the degree of colocalization of DHPR with RyR decreased significantly after deconvolution in all age groups: 3 days (62 ± 2% before deconvolution, 43 ± 3 after deconvolution) to 20 days old (79 ± 1% before deconvolution, 63 ± 2% after deconvolution). The data demonstrate that confocal images should be deconvolved before any quantitative analysis, such as colocalization index determination, to minimize the detrimental effects of out-of-focus light in coincident voxels.
Effects of progressive exercise and hypoxia on human muscle sarcoplasmic reticulum function
Authors: Duhamel T. A. , Green H. J. , Sandiford S. D. , Perco J. G. , Ouyang J.
Published: April 2004

This study examined the effects of progressive exercise to fatigue in normoxia (N) on muscle sarcoplasmic reticulum (SR) Ca2+cycling and whether alterations in SR Ca2+cycling are related to the blunted peak mechanical power output (POpeak) and peak oxygen consumption (V̇o2 peak) observed during progressive exercise in hypoxia (H). Nine untrained men (20.7 ± 0.42 yr) performed progressive cycle exercise to fatigue on two occasions, namely during N (inspired oxygen fraction = 0.21) and during H (inspired oxygen fraction = 0.14). Tissue extracted from the vastus lateralis before exercise and at power output corresponding to 50 and 70% of V̇o2 peak(as determined during N) and at fatigue was used to investigate changes in homogenate SR Ca2+-cycling properties. Exercise in H compared with N resulted in a 19 and 21% lower ( P < 0.05) POpeakand V̇o2 peak, respectively. During progressive exercise in N, Ca2+-ATPase kinetics, as determined by maximal activity, the Hill coefficient, and the Ca2+concentration at one-half maximal activity were not altered. However, reductions with exercise in N were noted in Ca2+uptake (before exercise = 357 ± 29 μmol·min−1·g protein−1; at fatigue = 306 ± 26 μmol·min−1·g protein−1; P < 0.05) when measured at free Ca2+concentration of 2 μM and in phase 2 Ca2+release (before exercise = 716 ± 33 μmol·min−1·g protein−1; at fatigue = 500 ± 53 μmol·min−1·g protein−1; P < 0.05) when measured in vitro in whole muscle homogenates. No differences were noted between N and H conditions at comparable power output or at fatigue. It is concluded that, although structural changes in SR Ca2+-cycling proteins may explain fatigue during progressive exercise in N, they cannot explain the lower POpeakand V̇o2 peakobserved during H.