bluuebunny/crossref_metadata_2025 huggingface dataset:
Passive acoustic detection of deep-diving beaked whales
Authors: Zimmer Walter M. X. , Harwood John , Tyack Peter L. , Johnson Mark P. , Madsen Peter T.
Published: November 2008

Beaked whales can remain submerged for an hour or more and are difficult to sight when they come to the surface to breathe. Passive acoustic detection (PAD) not only complements traditional visual-based methods for detecting these species but also can be more effective because beaked whales produce clicks regularly to echolocate on prey during deep foraging dives. The effectiveness of PAD for beaked whales depends not only on the acoustic behavior and output of the animals but also on environmental conditions and the quality of the passive sonar implemented. A primary constraint on the range at which beaked whale clicks can be detected involves their high frequencies, which attenuate rapidly, resulting in limited ranges of detection, especially in adverse environmental conditions. Given current knowledge of source parameters and in good conditions, for example, with a wind speed of 2m∕s, a receiver close to the surface should be able to detect acoustically Cuvier’s beaked whales with a high probability at distances up to 0.7km, provided the listening duration exceeds the deep dive interval, about 2.5h on average. Detection ranges beyond 4km are unlikely and would require low ambient noise or special sound propagation conditions.
Transitional wall pressure fluctuations on axisymmetric bodies
Authors: Hong Chinsuk , Shin Ku-Kyun , Jeon Jae-Jin , Kim Sang-Youn
Published: November 2008

This paper reports the characteristics of wall pressure fluctuations in the transition region of the flow over axisymmetric bodies. Measurements are conducted in a low noise wind tunnel to obtain the boundary-layer flow field, the local static pressures, and the wall pressure fluctuations using hot wires, micromanometers and flush-mounted microphones. The spatial and the temporal developments of Tollmien–Schlichting (T-S) waves were first observed in the time domain. The wall pressure fluctuations in the transitional boundary-layer flows were of intermittent pulses and intensified as they were convected downstream at typically 63% of the upstream velocity. The Wigner–Ville distributions are then obtained to examine the energy evolution jointly in time and in frequency. The center frequency of the T-S wave is decreased with increases of the boundary-layer thickness and the bandwidth of the energy distribution is broadened as the local Reynolds number is increased. Finally the nondimensional spectra of the transitional wall pressure fluctuations scaled on the outer variables was obtained and it was then found that the characteristic frequency of the T-S wave was related to the outer variables as ωδ∗/U∞≈0.2. The peak level of the pressure fluctuations during late transition at the characteristic frequency is about 10 dB higher than that of the fully developed flow.
A new equation for the accurate calculation of sound speed in all oceans
Authors: Leroy Claude C. , Robinson Stephen P. , Goldsmith Mike J.
Published: November 2008

A new equation is proposed for the calculation of sound speed in seawater as a function of temperature, salinity, depth, and latitude in all oceans and open seas, including the Baltic and the Black Sea. The proposed equation agrees to better than ±0.2m∕s with two reference complex equations, each fitting the best available data corresponding to existing waters of different salinities. The only exceptions are isolated hot brine spots that may be found at the bottom of some seas. The equation is of polynomial form, with 14 terms and coefficients of between one and three significant figures. This is a substantial reduction in complexity compared to the more complex equations using pressure that need to be calculated according to depth and location. The equation uses the 1990 universal temperature scale (an elementary transformation is given for data based on the 1968 temperature scale). It is hoped that the equation will be useful to those who need to calculate sound speed in applications of marine acoustics.
Effects of low-frequency biasing on spontaneous otoacoustic emissions: Frequency modulation
Authors: Bian Lin
Published: November 2008

It was previously reported that low-frequency biasing of cochlear structures can suppress and modulate the amplitudes of spontaneous otoacoustic emissions (SOAEs) in humans [Bian, L. and Watts, K. L. (2008). “Effects of low-frequency biasing on spontaneous otoacoustic emissions: Amplitude modulation,” J. Acoust. Soc. Am. 123, 887–898]. In addition to amplitude modulation, the bias tone produced an upward shift of the SOAE frequency and a frequency modulation. These frequency effects usually occurred prior to significant modifications of SOAE amplitudes and were dependent on the relative strength of the bias tone and a particular SOAE. The overall SOAE frequency shifts were usually less than 2%. A quasistatic modulation pattern showed that biasing in either positive or negative pressure direction increased SOAE frequency. The instantaneous SOAE frequency revealed a “W-shaped” modulation pattern within one biasing cycle. The SOAE frequency was maximal at the biasing extremes and minimized at the zero crossings of the bias tone. The temporal modulation of SOAE frequency occurred with a short delay. These static and dynamic effects indicate that modifications of the mechanical properties of the cochlear transducer could underlie the frequency shift and modulation. These biasing effects are consistent with the suppression and modulation of SOAE amplitude due to shifting of the cochlear transducer operating point.
Diagnostic imaging algorithm for cervical soft disc herniation.
Authors: Van de Kelft E , van Vyve M
Published: November 2008

MRI with surface coils is currently the preferred method for evaluating degenerative cervical spine disease. The differentiation between soft disc herniation and osteophytic spurs is not always obvious, however, on a 0.5 Tesla unit. The procedure of choice for soft disc herniation, MRI on a 0.5 T superconducting system associated with plain radiography of the cervical spine, in selecting patients for anterior cervical discectomy without interbody fusion (ACD), was evaluated. This prospective study comprised 100 patients with cervical radicular symptoms, not subsiding after conservative treatment. Plain radiographs were obtained for all patients. Patients without spinal instability, spondylosis, or major osteophytes on plain radiographs and without clinical findings of myelopathy underwent MRI (n = 59) on a 0.5 Tesla superconducting system. The other 41 patients underwent CT myelography. On MRI, herniation of a cervical soft disc was seen in 55 patients and the localisation corresponded well with the clinical symptoms. CT myelography showed a foraminal herniation in one of four selected patients with negative MRI. Fifty of 55 patients underwent ACD. All herniations were confirmed at operation, but in two patients there were important foraminal spurs not seen on MRI. It is concluded that 0.5 T MRI combined with plain radiographs offers an accurate, non-invasive test in the assessment of selected patients with cervical radiculopathy.
WATSON-CRICK BORDERED WORDS AND THEIR SYNTACTIC MONOID
Authors: KARI LILA , MAHALINGAM KALPANA
Published: November 2008

DNA strands that, mathematically speaking, are finite strings over the alphabet {A, G, C, T} are used in DNA computing to encode information. Due to the fact that A is Watson-Crick complementary to T and G to C, DNA single strands that are Watson-Crick complementary can bind to each other or to themselves in either intended or unintended ways. One of the structures that is usually undesirable for biocomputation, since it makes the affected DNA string unavailable for future interactions, is the hairpin: If some subsequences of a DNA single string are complementary to each other, the string will bind to itself forming a hairpin-like structure. This paper studies a mathematical formalization of a particular case of hairpins, the Watson-Crick bordered words. A Watson-Crick bordered word is a word with the property that it has a prefix that is Watson-Crick complementary to its suffix. We namely study algebraic properties of Watson-Crick bordered and unbordered words. We also give a complete characterization of the syntactic monoid of the language consisting of all Watson-Crick bordered words over a given alphabet. Our results hold for the more general case where the Watson-Crick complement function is replaced by an arbitrary antimorphic involution.
FUZZY ROBUST REGRESSION ANALYSIS BASED ON THE RANKING OF FUZZY SETS
Authors: KULA KAMİLE ŞANLI , APAYDIN AYŞEN
Published: November 2008

Since fuzzy linear regression was introduced by Tanaka et al., fuzzy regression analysis has been widely studied and applied in various areas. Diamond proposed the fuzzy least squares method to eliminate disadvantages in the Tanaka et al method. In this paper, we propose a modified fuzzy least squares regression analysis. When independent variables are crisp, the dependent variable is a fuzzy number and outliers are present in the data set. In the proposed method, the residuals are ranked as the comparison of fuzzy sets, and the weight matrix is defined by the membership function of the residuals. To illustrate how the proposed method is applied, two examples are discussed and compared in methods from the literature. Results from the numerical examples using the proposed method give good solutions.
FORMATION MECHANISM AND SURFACE EVOLUTION OF SILVER FILMS SPUTTERING DEPOSITED ON SILICONE OIL SUBSTRATES
Authors: YU SEN-JIANG , ZHANG YONG-JU
Published: November 2008

The formation mechanism and surface evolution of thin silver films deposited on silicone oil substrates by a DC-magnetron sputtering method are reported. As the film thickness increases, the deposited silver atoms first form compact clusters, then transfer to ramified aggregates and finally form a continuous film on the liquid substrate. After deposition, the surface morphology of the silver film is susceptible to evolve successively in the atmosphere condition, resulting in the formation of broad cracks and straight-sided (or worm-like) wrinkles. The evolution behaviors and underlying physical mechanisms of the cracks and wrinkles are presented and discussed in detail.
SYNTHESIS AND CHARACTERIZATION OF THE ANTIMICROBIAL 4-AMINO-DECYLPYRIDINIUM BROMIDE CATIONIC SURFACTANT
Authors: MADAAN PARAG , TYAGI V. K.
Published: November 2008

4-Amino-decylpyridinium bromide (ADPBr), an antimicrobial surface active agent, was synthesized by quaternization of 4-aminopyridine (AP) with decyl bromide (DBr). The reaction was carried out at 1:1.2 molar ratio of reactants (4-aminopyridine and decyl bromide, respectively) at 200°C for 10 min. The maximum yield of the product was 74.6%. The structure of the synthesized product was characterized by using modern analytical techniques, such as FT-IR, 1 H NMR, and 13 C NMR. The antimicrobial activity of the salt was evaluated with minimum inhibition concentration method and showed good activity against gram-negative bacteria. The MIC of the salt was found to be 600 ppm for 2 × 104 CFU/mL of E. coli.
SALT BATH OXINITRIDING OF GRAY CAST IRON
Authors: AHMADI M. , TEIMOURI M. , ALIOFKHAZRAEE M. , MOUSAVI KHOEE S. M.
Published: November 2008

Salt bath oxinitriding is a duplex surface treatment developed to improve tribological and corrosion properties of ferrous materials. In this research, gray cast iron samples were nitrided at the temperature range of 480°C–580°C, and then oxidized in an oxidative salt bath. The phase composition of surface layer was identified by X-ray diffraction. Using a microhardness tester, hardness of nitrided gray cast iron was measured. Corrosion behavior of treated (nitrided and oxinitrided) samples was evaluated using potentiodynamic polarization technique in 3.5% NaCl solution. XRD analyses indicate that the surface layer in nitrided and oxinitrided samples is composed of ε-iron nitride ( Fe2-3N ) and magnetite ( Fe3O4), respectively. Results show that the corrosion resistance of gray cast iron can be improved up to 170%.
THE EFFECT OF ROTOR DISC MATERIAL ON TRIBO BEHAVIOR OF AUTOMOTIVE BRAKE PAD MATERIALS
Authors: LIEW K. W. , EL-TAYEB N. S. M.
Published: November 2008

This work aims to investigate the effect of two different counterdisc materials, i.e. gray cast iron (GCI) and ductile gray cast iron (DGCI) on tribo behavior of non-commercial frictional materials (NF1, NF2, NF4, and NF5) and two other chosen commercial brake pads (CMA and CMB) under dry sliding contact conditions. The four non-commercial frictional materials were fabricated with various percentages of phenolic binder resin (15 and 20 vol.%) and reinforced with steel fibers (15 and 20 vol.%) using hot press molding methods. Tribo tests were carried out using a small-scale tribo-tester of pad-on-disc type. Friction coefficient and wear of non-commercial and commercial brake pads were measured against each counterdisc (GCI and DGCI) and compared. Then, the friction and wear characteristic are discussed by comparing the experimental results obtained for each kind of cast iron.

The results showed that maximum friction coefficient (0.4–0.5) of brake pad was attained at 2.22 MPa applied pressure and 2.1 m/s sliding speed when the frictional brake pad materials were tested against DGCI disc rotor. Meanwhile, similar wear rates for all frictional brake pad materials were sustained at higher applied pressure and sliding speed when tested against either type of rotor discs (GCI and DGCI).

The results on the other hand, indicated that non-commercial materials NF1 and NF4, gave better wear resistance compared to other frictional pad materials. NF2 exhibited the lowest wear resistance when tested against GCI and DGCI rotor disc at all applied pressure and sliding speeds. The latter result is referred to the low percentage binder resin in the friction material NF2.
PPARα/γ‐Independent Effects of PPARα/γLigands on Cysteinyl Leukotriene Production in Mast Cells
Authors: Yamashita Masamichi
Published: November 2008

Peroxisome proliferator‐activated receptor (PPAR)αligands (Wy‐14,643, and fenofibrate) and PPARγligands (troglitazone and ciglitazone) inhibit antigen‐induced cysteinyl leukotriene production in immunoglobulin E‐treated mast cells. The inhibitory effect of these ligands on cysteinyl leukotriene production is quite strong and is almost equivalent to that of the anti‐asthma compound zileuton. To develop new aspects for anti‐asthma drugs the pharmacological target of these compounds should be clarified. Experiments with bone‐marrow‐derived mast cells from PPARαknockout mice and pharmacological inhibitors of PPARγsuggest that the inhibitory effects of these ligands are independent of PPARsαandγ. The mechanisms of the PPAR‐independent inhibition by these agents on cysteinyl leukotriene production are discussed in this review.
Real-Time DVB-MHP Interactive Data Transcoding to Blu-Ray
Authors: Infante Sergio , Nasiopoulos Panos
Published: November 2008

Digital TV systems are being deployed worldwide, and interactive applications are being offered as part of the services. The unparalleled success of DVD technology has motivated the development of interactive services for broadcast TV, with DVB-MHP being the most widely used open standard in the world. Despite the similarities between DVB-MHP-based interactive TV and the new Blu-ray format, there still exist substantial differences that make the two systems incompatible. In this paper, we analyze the differences in the DVB-MHP and Blu-ray interactive formats and propose a transcoding scheme to convert live broadcast interactive TV to a Blu-ray compatible format.
Genetic Counseling in Renal Masses
Authors: López-Guerrero José Antonio , García-Casado Zaida , Fernández-Serra Antonio , Rubio-Briones José
Published: November 2008

All urologists have faced patients suffering a renal cancer asking for the occurrence of the disease in their offspring and very often the answer to this question has not been well founded from the scientific point of view, and only in few cases a familial segregation tree is performed. The grate shift seen in the detection of small renal masses and renal cancer in the last decades will prompt us to know the indications for familial studies, which and when are necessary, and probably to refer those patients with a suspected familial syndrome to specialized oncological centers where the appropriate molecular and familial studies could be done. Use of molecular genetic testing for early identification of at-risk family members improves diagnostic certainty and would reduce costly screening procedures in at-risk members who have not inherited disease-causing mutations. This review will focus on the molecular bases of familial syndromes associated with small renal masses and the indications of familial studies in at-risk family members.
Consensus Statement on Terminology and Management: Disorders of Sex Development
Authors: Houk C.P. , Lee P.A.
Published: November 2008

The recent consensus conference addressed several aspects of the care of patients with Disorders of Sex Development (DSD). Among these were proposals regarding a new terminology to classify patients, medical, surgical and psychological care and the decision regarding sex of rearing or gender assignment for those with the most severe forms of genital ambiguity. However, a basis was found to be lacking for the assignment of sex of rearing for many diagnoses as well as for some for whom no diagnosis could be made. Also, no consensus could be made concerning genital surgery, particularly in response to the call to defer all genital surgery until the age a child could decide. This in part involved the lack of a clear indication of the point when a person has arrived at a state of maturity enabling such a decision. However, consensus was reached that genital surgery should be performed for the infant with significant ambiguity, in spite of the lack of outcome data, when the parents unequivocally desire. It was clear that desired outcome data will not be available for decades, if ever. Also, blatantly lacking are adequate data concerning the impact of prenatal androgen on the fetal central nervous system regarding subsequent development of gender and sexual issues.
Steroidogenic Factor-1 (SF-1, Ad4BP, NR5A1) and Disorders of Testis Development
Authors: Lin L. , Achermann J.C.
Published: November 2008

Steroidogenic factor-1 (SF-1) (Ad4BP, NR5A1) is a nuclear receptor that regulates many aspects of adrenal and reproductive development and function. Consequently, deletion of the gene (Nr5a1) encoding Sf-1 in XY mice results in impaired adrenal development, complete testicular dysgenesis with Müllerian structures, and female external genitalia. Initial efforts to identify NR5A1 changes in humans focused on 46,XY individuals with combined adrenogonadal failure and Müllerian structures. Although this combination of clinical features is rare, 2 such patients harboring NR5A1 mutations have been described within the past decade. More recently, however, it has emerged that heterozygous loss of function mutations in NR5A1 can be found relatively frequently in children and adults with 46,XY disorders of sex development (DSD) but with apparently normal adrenal function. The phenotypic spectrum associated with these changes ranges from complete testicular dysgenesis with Müllerian structures, through individuals with mild clitoromegaly or genital ambiguity, to severe penoscrotal hypospadias or even anorchia. Furthermore, a non-synonymous polymorphism in NR5A1 may be associated with micropenis or undescended testes within the population. Taken together, these reports suggest that variable loss of SF-1 function can be associated with a wide range of reproductive phenotypes in humans.
Genetics of Spermatogenic Failure
Authors: Huang W.J. , Yen P.H.
Published: November 2008

Spermatogenesis is an ongoing developmental process in adult testes that requires the coordinated expression of many genes. The genetic causes of spermatogenic failure in men remain largely unknown, though abnormalities in the sex chromosomes constitute a significant portion of them. In this review, we focus on 3 disorders that involve the sex chromosomes and are often screened in infertility clinics. These are Klinefelter syndrome, Y chromosome microdeletion, and XX male syndrome. We describe their prevalence, the associated phenotypes, and the molecular mechanisms underlying the disorders and discuss the difficulties in identifying the causal genes contributing to the spermatogenic defects. Currently, there are no effective therapies for the spermatogenic failure in the patients, and conception through assisted reproductive technology bears the risk of passing genetic abnormalities to the next generation.
Environmental Endocrine Disrupters
Authors: Toppari J.
Published: November 2008

Androgens, anti-Müllerian hormone, and insulin-like factor 3 are testis-derived hormones that regulate male sexual differentiation. Correct timing of secretion and action of these hormones is critical for normal development. Endocrine disrupters are exogenous substances that cause adverse effects in the endocrine system. They can impair the synthesis, distribution, metabolism, excretion, and action of hormones. Male sexual differentiation can be disrupted by antiandrogens and synthetic estrogens such as diethylstilbestrol. The number of identified environmental antiandrogens keeps growing and these compounds show clear dose-additive effects causing worry that a mixture of these chemicals can cause adverse effects even when each compound is present at a low concentration. This is also a demanding research task for endocrinologists working with disorders of sex differentiation.
Pseudocyst in the Pancreatic Tail Associated with Chronic Pancreatitis Successfully Treated by Transpapillary Cyst Drainage
Authors: Naitoh Itaru , Ohara Hirotaka , Okayama Yasutaka , Nakazawa Takahiro , Ando Tomoaki , Hayashi Kazuki , Okumura Fumihiro , Kitajima Yasuhiro , Ban Tessin , Miyabe Katsuyuki , Ueno Koichiro , Joh Takashi , Sano Hitoshi
Published: November 2008

We report a 50-year-old male with pseudocysts in the pancreatic tail associated with chronic pancreatitis successfully treated by transpapillary cyst drainage. He had previously undergone ultrasonography-guided percutaneous cyst drainage for a pancreatic pseudocyst in our hospital. He was readmitted due to abdominal pain and fever. Computed tomography showed recurrence of a pseudocyst in the pancreatic tail measuring 5 cm in diameter. Since conservative treatment failed, endoscopic retrograde pancreatography was performed. There was communication between the pseudocyst and the main pancreatic duct, and pancreatic duct stenosis proximal to the pseudocyst. First, transpapillary pancreatic duct drainage was performed using a plastic stent, but the pseudocyst did not decrease in size and became infected. After removal of the stent, a pigtail type nasocystic catheter was placed in the pseudocyst via the pancreatic duct. The pseudocyst infection immediately disappeared, and the pseudocyst gradually decreased and disappeared. After removal of the nasocystic catheter, no recurrence was observed. As transpapillary drainage of pancreatic pseudocyst, cyst drainage and pancreatic duct drainage have been reported. In our patient with pseudocyst in the pancreatic tail, duct drainage was ineffective and the pseudocyst was infected, whereas cyst drainage was very effective. We considered that cyst drainage by a nasocystic catheter was the first-line therapy as the transpapillary drainage of the pancreatic pseudocyst.
Effect of n–3 Polyunsaturated Fatty Acids in Asthma after Low-Dose Allergen Challenge
Authors: Schubert R. , Kitz R. , Beermann C. , Rose M.A. , Lieb A. , Sommerer P.C. , Moskovits J. , Alberternst H. , Böhles H.J. , Schulze J. , Zielen S.
Published: November 2008

Background: We investigated the anti-inflammatory potential of n–3 polyunsaturated fatty acids (PUFA) on specific bronchial inflammation. Allergic asthmatics were challenged using a low-dose allergen provocation model. Methods: Our parallel double-blinded study randomly assigned 23 house dust mite-allergic asthmatics (aged 22–29 years; 13 females, 10 males) to dietary supplementation with either an n–3 PUFA-enriched fat blend (0.69 g/day) or placebo for 5 weeks. After 3 weeks, the patients were challenged daily with low doses of mite allergen for 2 weeks. Primary outcome parameters were effects on lung function (forced expiratory volume in 1 s, FEV1) and exhaled nitric oxide (eNO) as a marker of bronchial inflammation. Results: Even before the bronchial challenge, eNO was significantly lower in the n–3 PUFA group (p = 0.014). Levels of eNO increased during allergen exposure in both groups, but differences in means were significantly lower in the n–3 PUFA group (p = 0.022). During the low-dose allergen challenge, there were no differences between the groups with regard to symptoms, FEV1 or the allergen dose required to induce deterioration of lung function (PD20). Numbers of sputum eosinophils did not differ significantly, while serum eosinophils (10.1 ± 0.1.84 vs. 5.79 ± 0.69%) as well as changes in eosinophilic cationic protein (20.5 ± 9.93 vs. –1.68 ± 4.36 ng/ml) and in vitro cysteinyl leukotriene release (2,889 ± 872 vs. 1,120 ± 173 ng/ml) were significantly lower in the n–3 PUFA group (p < 0.05 each). Conclusion: Our results provide evidence that dietary supplementation with n–3 PUFA is able to reduce bronchial inflammation even after low-dose allergen challenge.
Sequence Diversity of the Bla g 4 Cockroach Allergen, Homologous to Lipocalins, from Blattella germanica
Authors: Jeong Kyoung Yong , Yi Myung-hee , Jeong Kyoung-jin , Lee Haeseok , Hong Chein-Soo , Yong Tai-Soon
Published: November 2008

Background: The cockroach allergen Bla g 4, a putative lipocalin, is known to exhibit frequent sequence variations. However, the previously reported cDNA sequences are truncated at the N terminus. This study was undertaken to investigate the mechanisms by which these sequence variations are generated. Methods: Rapid amplification of cDNA ends PCR and RT-PCR were performed to obtain the full sequence of the Bla g 4 cDNA, and PCR was also used to clone the Bla g 4 genomic DNA. In addition, Bla g 4 protein variants were analyzed by two-dimensional gel electrophoresis. Results: Nine additional amino acid residues at the N terminus of Bla g 4 were identified, and 2 genes encoding Bla g 4, both of which consisted of 5 exons, were cloned. Examination of 34 clones of Bla g 4 cDNA obtained by RT-PCR revealed 14 variants. In particular, Bla g 4 sequences showed frequent clusters of variations in residues 38–45, 61–82 and 144–163. Differences in cDNA sequences may imply that RNA sequences are edited after transcription. More than 10 spots were identified between pH 5 and 7 upon two-dimensional gel electrophoresis, indicating that multiple variants of Bla g 4 are produced at the protein level. Conclusions: Genetic polymorphisms among individual cockroaches, the existence of multiple genes and sequence variations caused by RNA editing produce sequence diversity of Bla g 4, which may influence its allergenicity. The sequence information obtained in this study will be helpful for the standardization of the cockroach allergen and thereby aid in the development of diagnostics and immunotherapeutics.
Effects of Verapamil, an Antagonist of L-Type Calcium Channels, on Cardiovascular Symptoms in Alcohol Withdrawal
Authors: Kähkönen Seppo , Bondarenko Boris B. , Lipsanen Jari , Zvartau Edwin E.
Published: November 2008

Aims: We studied whether verapamil, a Ca2+ channel blocker, affects cardiovascular symptoms in alcohol withdrawal. Methods: Cardiovascular effects of verapamil (5 mg intravenously) were compared in 20 alcohol-dependent subjects during alcohol withdrawal (n = 10) on days 1, 2 and 10 and during early recovery (n = 10; duration 45 ± 4.1 days). The heart rate was obtained from the electrocardiogram. Systolic and diastolic blood pressures were measured with a sphygmomanometer by Korotkoff. Stroke volume was studied by impedance cardiography. Results: Significant differences in verapamil effects on systolic and diastolic blood pressure and stroke volume and total peripheral resistance were observed in patients with withdrawal when compared with those in early recovery. Conclusion: L-type Ca2+ channels may modify vascular tone in alcohol withdrawal.
In vitro Use of Polyethylene-(1,2-14C)-Glycol to Measure Extracellular Space in Renal Cortex Slices from Neonatal, Immature and Adult Mammals
Authors: Chesney Russell W. , Jax Diane K. , Mohyuddin Fazl , Scriver Charles R.
Published: November 2008

Polyethylene-(1, 2-14C)-glycol is a reliable probe of the extracellular space in renal cortex slices. The PEG distribution volume is similar to that measured with inulin (24–25% of wet slice weight at 30 min). Comparable values were found using PEG and inulin in slices from newborn, 4-week-old and adult animals. Contamination of PEG with low molecular polymers did not occur, in contrast with our experience with stored inulin.
Characterization of the Collagenous Domain of Bovine Glomerular Basement Membrane
Authors: Hudson Billy G. , Fox Wesley
Published: November 2008

Bovine glomerular basement membrane was subjected to limited pepsin digestion and the solubilized collagenous polypeptides were characterized. Several electrophoresis systems were used which enabled an examination over a molecular weight range from 20,000 to > 106. A 0.1% SDS-5% polyacrylamide gel system resolves the reduced digestion product into 17 polypeptides ranging in molecular weight from 78,000 to 340,000. The larger collagenous components were resolved on a 0.1 % SDS-2.5% agarose gel system. The nonreduced digestion product resolves into 13 components which vary in molecular weight from 85,000 to 5 million. Upon reduction, the majority of this material is converted to a 165,000 molecular weight component(s) and cross-linked (aldehyde derived) multimers of this component(s) containing as many as 6 cross-linked monomers. The digestion product was subjected to a second pepsin digestion after reduction and alkylation under nondenaturing conditions. This results in a conversion of the larger polypeptides to three lower molecular weight peptides, two of which exhibit an electrophoretic migration identical to α1-and α2-chains of collagen. The results indicate that the collagenous domain of glomerular basement membrane consists of various size collagen molecules connected by disulfide bonds and aldehyde-derived cross-links to form high molecular weight aggregates containing as many as 30 of these polypeptides, and that the larger collagenous polypeptides contain α-size segments within their structure.
Evidence for H2 Receptor Activity on Glomerular Cells
Authors: Sperk G. , Ratzenhofer E. , Simbruner G. , Coradello H. , Pollak A. , Lubec G.
Published: November 2008

The role of histamine in physiological and pathological states has not been fully elucidated. In the pathological state histamine release can be induced by several mechanisms. The most frequent events are IgE-mediated release, complement-mediated release and release by chemical agents. During inflammation histamine is set free and contributes to the course of inflammatory processes, either enhancing or inhibiting inflammatory reactions. In order to look for a target in the glomerulum we examined H2 receptor binding to isolated glomerular cells using 3H-cimetidine as ligand. Two binding sites were detected, a low affinity site with a kD = 6.3 µM and a high affinity site exhibiting a kD = 0.18 µM. These findings are comparable to properties of 3H-cimetidine receptor binding to brain membranes.
Structural Organization of Heterogeneous Basal Laminas in Human Glomeruli
Authors: Huang Thomas W.
Published: November 2008

Differential response to 5 M guanidine, pH 7.0, shows at least two classes of glomerular basal laminas: epithelial and endothelial-mesangial. The former is the predominant element, folding into capillary tufts and loops but never completely encircle the entire circumference of glomerular capillaries. It remains as a single, continuous sheet within each glomerulus. The mesangial basal lamina partitions the vascular space into individual capillary lumen. The endothelial basal lamina, which extends from mesangium to encircle capillary lumens, is poorly developed, and undetectable in most capillaries. The organization of these two classes of basal laminas provides a structural framework for understanding glomerular permeability, especially the spatial relationship between capillary lumens and the mesangium. Interruption of the juxtaglomerular epithelial basal lamina, with sprouting of a new endothelial-mesangial bud, and formation of a new glomerular capillary tuft are noted in a group of patients with diabetic glomerulosclerosis and chronic renal failure. Wrinkling and resorption of the juxtamesangial epithelial basal lamina with formation of a new epithelial basal lamina are also observed. These findings indicate that the mesangium and the juxtamesangial epithelial basal lamina may be the active site of glomerular basal lamina resorption, turnover, and neoangiogenesis.
Renal Injury and Proteinuria in Female Spontaneously Hypertensive Rats
Authors: Feld Leonard G. , Brentjens Jan R. , Van Liew Judith B.
Published: November 2008

This investigation describes the evolution of functional and morphological changes in the kidney of female spontaneously hypertensive rats (SHR; 5–90 weeks) and control animals of the same genetic strain, Wistar-Kyoto (WKY). Systolic blood pressure in SHR was 162.0 ± (SD) 14.1 mm Hg up to 45 weeks, then increased to 189.4 ± (SD) 16.6 mm Hg (50–90 weeks). Blood pressure in WKY controls remained constant (117.8 ± 13.6 mm Hg, 5–100 weeks). Protein excretion in the SHR was higher than controls (1.5 ± 0.5 mg/24 h x 100 g BW, 5–100 weeks) from week 30 on. At 90 weeks, excretion rose to 26.1 ± 9.8 mg/24 h x 100 g BW and is predominately an albuminuria. After 70 weeks superficial tubular fluid albumin concentration in the SHR is significantly increased (p < 0.001) over controls. Microscopic changes were evident in glomeruli, tubules, interstitium and arterial vessels at 72–90 weeks and demonstrated an increasing gradient of severity from outer to inner cortex. Glomeruli show sclerosis, fibrinoid necrosis and pericapsular fibrosis. Glomeruli studied with a polyanionic stain revealed a marked decrease in staining affinity of deep, compared to superficial glomeruli. The arterial lesions consisted of thickening of the intima and hyperplasia of the media. WKY kidneys were unremarkable. The selectivity of renal injury and proteinuria in the female SHR is similar to that in the male SHR. However, the evolution of these changes is delayed and may be related to a lower blood pressure until 50 weeks of age.
Effect of Furosemide on Sodium and Potassium Flow at the End of the Juxtamedullary Descending Limb in Psammomys obesus
Authors: Dobyan Dennis C. , Arrascue Jose F. , de Rouffignac Christian , Roinel Nicole , Jamison Rex L.
Published: November 2008

To examine the effect of reducing medullary interstitial solute concentration on sodium and potassium flow at the end of the juxtamedullary descending limb in Psammomys obesus, micropuncture was performed on the exposed left renal papilla. After a control period, furosemide was administered to reduce medullary interstitial solute concentration without altering the delivery of sodium, potassium and water from the proximal tubule. The fraction of filtered sodium remaining at the end-descending limb before (52 ± 4.9%) and after furosemide (55 + 4.2%) was not significantly different, despite a fall in tubule-to-plasma osmolality from 4.32 to 2.00 (p < 0.001). In contrast, the fraction of filtered potassium delivered to the end-descending limb fell from 91 ± 9.0% to 61 + 8.0% (p < 0.001). As expected, the fraction of filtered sodium and potassium remaining at the end of the accessible proximal tubule of the superficial nephron was not changed after the administration of furosemide. While these findings do not provide additional support for the thesis of transepithelial sodium addition to the juxtamedullary descending limb, they strongly suggest that transepithelial entry (secretion) of potassium normally occurs upstream to the juxtamedullary hairpin turn of Psammomys obesus.
Influence of Bradykinin and Papaverine on Renal and Glomerular Hemodynamics in Dogs
Authors: Thomas Charles E. , Bell Darwin , Navar Gabriel
Published: November 2008

Although it is recognized that vasodilator-induced increases in renal plasma flow are not associated with increases in glomerular filtration rate (GFR), the mechanism responsible for the failure of GFR to exhibit plasma flow dependency under these circumstances remains uncertain. To evaluate this problem further, the effects of intra-arterial infusion of two vasodilators, bradykinin (n = 7) and papaverine (n = 6), on renal hemodynamics and glomerular function of dogs were determined. Both agents increased renal blood flow; however, GFR and single nephron GFR (SNGFR) remained unchanged during bradykinin infusion and decreased significantly during papaverine infusion. Transglomerular hydrostatic pressure and mean effective filtration pressure were not altered during bradykinin infusion but were significantly reduced by papaverine. Neither agent altered the glomerular filtration coefficient. These observations indicate that, in the dog, the GFR responses during renal vasodilation are dependent primarily on the effective filtration pressure.
Difference in Urinary N-Acetyl-β-D-Glucosaminidase Activity between Male and Female Beagle Dogs
Authors: Nakamura Masuhisa , Itoh Takako , Miyata Kenji , Higashiyama Noboru , Takesue Hideo , Nishiyama Shinya
Published: November 2008

Urinary N-acetyl-β-D-glucosaminidase (NAG) activity differed greatly between male and female beagle dogs in an age-matched group. The NAG activity in males per animal, per body weight, or per 16-hour urine sample was approximately double that in females and was 2.4-fold higher when the activity was considered relative to urinary creatinine. On the other hand, alanine aminopeptidase activity relative to urinary creatinine was not significantly different between males and females. These findings indicate that when using urinary NAG activity to detect drug nephrotoxicity in dogs, some consideration must be given to different control levels between males and females before starting drug administration.
Comparative Regional Distribution of Angiotensin-I-Converting Enzyme in the Rat, Rabbit, Dog, Monkey and Human Kidneys
Authors: Morin J.P. , Moulin B. , Borghi H. , Grise P. , Fillastre J.P.
Published: November 2008

Kidney is the main source of the production of renin and angiotensin, while also being one of their main target organs. This study was designed to determine the regional distribution of angiotensin-I-converting enzyme (ACE) in the kidney using a biochemical approach. Interspecies variations were analyzed in human, monkey, rabbit, dog and rat kidneys. Kidney ACE content differed among species with decreasing contents as follows: rabbit > human- > monkey > dog > rat. In rabbit, human, monkey and dog kidneys, we observed predominant cortical distribution of ACE compared with the medulla or papilla; median cortex/papilla ACE activity ratio was 19, 14, 9 and 7 for the rabbit, human, dog and monkey, respectively. In rat kidney, ACE predominantly distributes in the outer medulla, while cortex ACE content appears to be low. The difference in ACE distribution in the rat kidney and to a lesser extent in the dog kidney when compared to rabbit, monkey or man should be taken into account when extrapolating to the human renal hemodynamic studies, which are frequently performed in rats or dogs.
Action of Aldosterone on Protein Expression in Cultured Collecting Duct Cells from Neonatal Rabbit Kidney
Authors: Minuth Will W. , Zwanzig Marianne , Gross Peter
Published: November 2008

To investigate whether ‘aldosterone-induced proteins’ could be detected in mammalian species, cultured renal collecting duct epithelia from neonatal rabbit kidneys were labelled under aldosterone administration with radioactive methionine and subsequently fractionated into cytosolic and coarse membrane protein fractions. Newly synthesized proteins were then analyzed by SDS-PAGE, isoelectric focussing and two-dimensional electrophoresis. Quantitative estimates of individual newly synthesized proteins were performed utilizing gel slicing, scintillation counting and autoradiography. The labelling experiments demonstrated that, in comparison to controls, aldosterone (1× 10-6 M) generally increased the amount of radioactive protein. No qualitative changes in the pattern of newly synthesized proteins and, therefore, no classical aldosterone-induced proteins were observed. The increase of radioactive protein was already seen after 1, 6, and 18 h of hormone treatment. The effect could be blocked partially by spironolactone (1.5×10-4M), and totally by amiloride (1×10-6M), g-strophantin (5×10-4M), and cycloheximide (1 × 10-6M). Thus, the interference of aldosterone action at the receptor level, the Na+ channels and the Na+/K+-ATPase pump demonstrate that the expression of proteins in cultured renal collecting duct cells is a sensitive system and seems to be controlled by aldosterone at the receptor level, but also counter-controlled by specific plasma membrane sites.
Cation Channels in the Apical Membrane of Collecting Duct Prinicipal Cell Epithelium in Culture
Authors: Laskowski Frank H. , Christine Chadwick W. , Gitter Alfred H. , Beyenbach Klaus W. , Gross Peter , Frömter Eberhard
Published: November 2008

The apical cell membrane of cultured monolayers of collecting duct principal cells was investigated with the patch-clamp technique to study single ion channels. A broad spectrum of channel events was observed which complicated the analysis. Although principal cells absorb mainly Na+ ions and although most patches must have contained an Na+ conductance as evidenced by asymmetric clamp currents in the presence of amiloride, single Na+ channel events could not be identified with certainty, possibly because single-channel conductance was too low (≤5pS). Instead, non-selective cation channels of 21.2 ± 4.0 pS were frequently observed. They were impermeable to choline and anions but did not discriminate between Na+ and K+. These channels, however, do not appear to participate in active Na+ absorption. Different types of K+ channels were observed: a high-conductance Ca2+-activated K+ channel and a bursting low-conductance K+ channel. Since the former channel has been denied a role in K+ secretion/ absorption in native collecting ducts, the latter might be involved. In addition three types of CΓ channels have been observed which will be described separately. At least one of those, a 30-pS outwardly rectifying Cl- channel appears to allow small amounts of Cl- ions to be absorbed across principal cells.
Ion Channels in Madin-Darby Canine Kidney Cells
Authors: Lang F. , Friedrich F. , Paulmichl M. , Schobersberger W. , Jungwirth A. , Ritter M. , Steidl M. , Weiss H. , Wöll E. , Tschernko E. , Paulmichl R. , Hallbrucker C.
Published: November 2008

Ion channels in Madin-Darby canine kidney cells serve transepithelial chloride transport and probably cell volume regulation. Three distinct potassium channels and one anion channel have been revealed by patch clamp studies in Madin-Darby canine kidney cells. The potassium channels are activated by an increase in intracellular calcium activity. A number of hormones activate the potassium channels by an increase in intracellular calcium activity. However, under certain conditions the hormones hyperpolarize the cell membrane without increasing intracellular calcium activity sufficiently to activate the calcium-sensitive potassium channels. Thus, the hormones may activate potassium channels via another, as yet undefined, intracellular mechanism. The anion channel is stimulated by cAMP. Another factor modifying channel activity is cell volume: cell swelling leads probably to subsequent activation of potassium and anion channels. The net result is a variable transient hyperpolarization followed by a sustained depolarization of the cell membrane.
Early Acute Effects of Mercuric Chloride on Synthesis and Release of Kallikrein and on Distal Tubular Morphology of Rat Renal Cortical Slices
Authors: Girolami Jean Pierre , Orfila Claudine , Cabos-Boutot Ghisiaine , Pecher Christiane , Bascands Jean Loup , Colle Allain
Published: November 2008

The effect of mercuric chloride on kallikrein content and secretion of renal cortical slices was studied. Mercuric chloride showed dose-dependent inhibition of the secretion of immunoreactive and active kallikrein in the medium associated with a relative increase in the kallikrein tissue content of slices. However the net de novo biosynthesis was also reduced. Active and inactive kallikrein exhibited the same percentage of inhibition indicating that the activation mechanism of prokallikrein was not affected. These results suggest that mercuric chloride exerts an inhibition on tubular secretion but also on the tissular biosynthesis of kallikrein in these in vitro conditions. Morphological study of slices incubated in the presence of mercury also revealed significant tissular lesions which were located on the proximal tubule, but distal tubular changes were also observed. Distal nephrons were identified by the presence of immunoreactive kallikrein with the peroxidase-antiperoxidase method. These ultrastructural alterations included an increase in number and size of lysozomes, vacuoles and lipid droplets. These lesions were associated with an increased release of the lysozomal enzyme N-acetyl-β-D-glucosaminidase. Since these distal tubular lesions are associated with inhibition of kallikrein secretion which is specifically located in the distal tubule, these results suggest that acute exposure of kidney cortical slices to mercuric chloride causes rapid and marked ultrastructural changes not only on the proximal tubule but also induced structural and biochemical effects at the distal tubule level. As incubation of mercuric chloride did not induce any direct alterations of immunoreactive and active kallikrein, it is likely that the observed inhibition of kallikrein synthesis and secretion are secondary to the morphological lesions.
Effects of Low-Potassium Diet on N-Ethylmaleimide-Sensitive ATPase in the Distal Nephron Segments
Authors: Garg Lal C. , Narang Neelam
Published: November 2008

The present study was undertaken to investigate whether or not potassium deficiency influences N-ethylmaleimide (NEM)-sensitive ATPase in the distal nephron segments of the rat. One group of animals was fed a low-K diet, whereas the normal K-group was given the same diet after supplementation with KCl. The nephron segments examined were: the medullary and cortical thick ascending limbs, the distal convoluted tubule, and the cortical, outer and inner medullary collecting ducts. NEM-sensitive ATPase activity in microdissected segments was measured by a fluorometric microassay. The plasma K+ concentration in the low-K group was 3.1 ± 0.3 mEq/l compared with 4.2 ± 0.1 mEq/1 in the normal-K group. NEM-sensitive ATPase activity in the outer medullary collecting duct of low-K diet animals was significantly greater than in normal-K animals. There was no significant difference in NEM-sensitive ATPase activity between the two groups of animals in the other nephron segments examined. It is suggested that NEM-sensitive H-ATPase activity in the outer medullary collecting duct is modulated by the potassium status of the animal.