bluuebunny/crossref_metadata_2025 huggingface dataset:
Hepatoprotective effect of ginsenoside Rb1 and compound K on tert‐butyl hydroperoxide‐induced liver injury
Authors: Lee Hae‐Ung , Bae Eun‐Ah , Han Myung Joo , Kim Nam‐Jae , Kim Dong‐Hyun
Published: September 2005

Abstract: Background/Aim: The main component of Panax ginseng, which have been reported by many researchers, are ginsenoside Rb1, Rb2 and Rc. Orally administered ginsenosides are metabolized to 20‐O‐β‐d‐glucopyranosyl‐20(S)‐protopanaxadiol (compound K) by intestinal bacteria and absorbed to blood. To understand its hepatoprotective effect and its mechanism, the effects of ginsenoside Rb1 and its metabolite compound K on chemically injured HepG2 cells and mice were investigated.

Methods: Ginsenoside Rb1 and compound K were isolated from ginseng. Hepatotoxicity of HepG2 cells and mice was induced by tert‐butyl hydroperoxide (t‐BHP). Cytotoxicity for HepG2 cells and serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) for mice as markers of hepatoprotective activity were measured.

Results: Compound K protected HepG2 cell cytotoxicity induced by t‐BHP. However, ginsenoside Rb1 did not inhibit cytotoxicity. Nevertheless, both ginsenoside Rb1 and compound K significantly inhibited the increment of ALT and AST induced by t‐BHP in mice, when it was orally administered. However, intraperitoneally administered ginsenoside Rb1 did not inhibit the increment of plasma ALT and AST induced by t‐BHP in mice. These compounds did not exhibit antioxidant activity. However, compound K showed the potent membrane stabilizing activity more than ginsenoside Rb1.

Conclusion: Compound K, which was produced from ginsenosides of Panax ginseng in intestine, could protect liver injury.
Outcome from molecular adsorbent recycling system (MARS™) liver dialysis following drug‐induced liver failure
Authors: Lee Kang‐Hoe , Lee Margaret Kwee‐Hiang , Sutedja Dede Selamat , Lim Seng‐Gee
Published: September 2005

Abstract: Rationale: Fulminant liver failure from drug ingestion is associated with a high mortality, and the introduction of liver transplantation has improved the mortality significantly if done in a timely fashion. Recently, molecular adsorbent recycling system (MARS™) liver dialysis has been introduced as a support for liver failure with varying results. We review our experience with drug‐induced liver failure and the impact of MARS™ liver dialysis on the outcome, in a setting where cadaveric liver transplantation is rarely available.

Results: A total of 13 patients were treated, and 40 sessions of MARS™ liver dialysis were conducted in the intensive care unit. The majority of cases were because of herbal medicine toxicity. Total bilirubin, conjugated bilirubin, and delta bilirubin were significantly reduced, with no change in unconjugated bilirubin. All patients satisfied the criteria for urgent liver transplantation with an average Model End Stage Liver Disease (MELD) score of 35. Only one patient received a liver transplantation from a live donor (right lobe). Overall mortality was 85%. Median time‐to‐death from the start of MARS™ was 8 days.

Conclusions: MARS™ liver dialysis in a setting without timely liver transplantation is associated with a poor outcome. It does, however, provide a window of time for consideration of living donors in the setting of limited cadaveric donors.
Upregulation ofGlypican‐3expression in hepatocellular carcinoma but downregulation in cholangiocarcinoma indicates its differential diagnosis value in primary liver cancers
Authors: Man Xiao‐Bo , Tang Liang , Zhang Bao‐Hua , Li Shen‐Jing , Qiu Xiu‐Hua , Wu Meng‐Chao , Wang Hong‐Yang
Published: September 2005

Abstract: Background/Aim:Expression alteration ofGlypican‐3(GPC3) is associated with several malignancies and has been identified as an overexpressed gene in hepatocellular carcinoma (HCC). In this studyGPC3expression in intrahepatic chanlangiocarcinoma (ICC), gallbladder cancer and HCC was quantitatively detected.

Methods:Real‐time quantitative reverse transcription polymerase chain reaction was used to detect the expression level ofGPC3.

Results:GPC3expression was elevated more than two‐fold in HCC compared with adjacent tissue in 90 of 100 HCC cases. The average expression level ofGPC3was significantly higher in HCC than that in adjacent liver tissues (P<0.0001). Only in four of 21 ICC casesGPC3expression was upregulated more than two‐fold in tumor tissues.GPC3expression was downregulated in gallbladder cancer in 12 of 13 cases and the average expression level was significantly lower than that in normal gallbladder tissues (P<0.05).

Conclusion:The different expression patterns ofGPC3in HCC and ICC suggested that it might play a different role in theses tumors and could serve as a biomarker for differential diagnosis of HCC and ICC.
Mortality predictors in liver transplant recipients with recurrent hepatitis C cirrhosis
Authors: Saab Sammy , Niho Henry , Comulada Scott , Hiatt Jonathan , Durazo Francisco , Han Steven , Farmer Douglas G. , Holt Curtis , Yersiz Hasan , Goldstein Leonard I. , Ghobrial R. Mark , Busuttil Ronald W.
Published: September 2005

Abstract: Background/Aim:Recipients of orthotopic liver transplant for hepatitis C (HCV) invariably develop recurrent disease. The risk factors for death and retransplantation following the development of cirrhosis from HCV are unclear. The aim of this study was to identify predictors of survival in liver transplant recipients who develop cirrhosis from recurrent HCV.

Methods:We reviewed records of patients who underwent liver transplantation for cirrhosis due to HCV between January 1990 and December 2001. Prognostic factors of patient survival following the development of recurrent cirrhosis were identified through multivariate analysis.

Results:During the study period, 511 patients underwent transplantation for HCV cirrhosis. Of these, 65 patients (13%) developed biopsy proven recurrent cirrhosis from HCV; 43 (8%) were relisted for transplantation, and 24 (5%) underwent retransplantation. The overall Kaplan–Meier patient survival rates after the histologic diagnosis of cirrhosis at 1 and 5 years were 66% and 30%, respectively. A multivariate Cox proportional hazards model showed patients with higher last (i.e. at follow‐up or prior to retransplantation) International normalized ratio (INR) values (hazard ratios (HR)=2.02, 95% confidence interval 1.26, 3.24,P<0.01) to have an increased risk of death.

Conclusion:Our results suggested survival was decreased after the diagnosis of cirrhosis from recurrent HCV. Higher INR was associated with an increased risk of death following the development of cirrhosis.
High glucose stimulates hepatic stellate cells to proliferate and to produce collagen through free radical production and activation of mitogen‐activated protein kinase
Authors: Sugimoto Rie , Enjoji Munechika , Kohjima Motoyuki , Tsuruta Satoshi , Fukushima Marie , Iwao Masataka , Sonta Toshiyo , Kotoh Kazuhiro , Inoguchi Toyoshi , Nakamuta Makoto
Published: September 2005

Abstract: Background: Nonalcoholic steatohepatitis is a clinicopathologic condition that may progress to liver fibrosis. Hyperglycemia is supposed to be one of the factors inducing hepatic fibrogenesis, but the mechanism has not been fully clarified. Oxidative stress is increasingly found in patients with diabetes/hyperglycemia in which conditions reactive oxygen species (ROS) are produced.

Methods: We performed experiments using hepatic stellate cells (HSCs) in culture in order to confirm the effect of high glucose concentrations on cell proliferation, type I collagen production, ROS production and activation of mitogen‐activated protein (MAP) kinase pathway.

Results: High glucose stimulated cell growth of HSCs and up‐regulated the levels of activated/phosphorylated extracellular signal‐regulated kinase 1/2 and free radical production in HSCs. The MAP kinase phosphorylation and cell proliferation were suppressed by diphenylene iodonium chloride, an NADPH oxidase inhibitor, and by calphostin C, a protein kinase C (PKC)‐specific inhibitor. Increased type I collagen mRNA and protein levels were also observed in HSCs at high glucose concentrations.

Conclusions: Our findings indicate that high glucose concentrations may stimulate ROS production through PKC‐dependent activation of NADPH oxidase, and induce MAP kinase phosphorylation subsequent to proliferation and type I collagen production by HSCs.
Tumor growth‐promoting cellular host response during liver atrophy after portal occlusion
Authors: Mueller Lars , Goettsche Juliane , Abdulgawad Awad , Vashist Yogesh K. , Meyer Jannine , Wilms Christian , Hillert Christian , Rogiers Xavier , Broering Dieter C.
Published: September 2005

Abstract: Background/Aims: Clinical observations suggest cancer progression after preoperative segmental portal vein occlusion, a procedure to prevent liver failure after major hepatic resections. The aim of this study was to determine whether portal occlusion induces host reactions which promote cancer invasion and angiogenesis.

Methods: The rat model of portal branch ligation (PBL) was compared with partial hepatectomy (PH) and sham operation (SO) and evaluated for the expression of heat shock protein‐70 (hsp70), heme oxygenase‐1 (hmox1), early growth response gene‐1 (Egr‐1) and urokinase‐type plasminogen activator (uPA), its inhibitor (PAI‐1) and receptor (uPAR).

Results: 
Portal deprivation after PBL was associated with a regression of liver tissue to 25% of its original mass within 8 days with only modest fibrotic changes. During the progression of atrophy, there were significant inductions of hsp70‐, hmox1‐ and Egr‐1‐mRNA in comparison with regenerating liver tissue. PAI‐1‐specific mRNA was transiently elevated at 3 – 48 h after PBL in the atrophying lobes, whereas uPA and uPAR were unaffected in comparison with PH or SO.

Conclusion: 
Hepatic atrophy caused by PBL is associated with increased expression of genes known to promote tumor growth. These host events represent a possible explanation for the tumor progression after portal occlusion and require further evaluation.
Expression of hypoxia inducible factor‐1α during liver regeneration induced by partial hepatectomy in rats
Authors: Maeno Hiroshi , Ono Takashi , Dhar Dipok Kumar , Sato Takashi , Yamanoi Akira , Nagasue Naofumi
Published: September 2005

Abstract: Background/Aims: It has been well established that hypoxia inducible factor‐1α (HIF‐1α) transcribes essential factors in cell preservation, including angiogenesis, during hypoxia. However, the transition of HIF‐1α expression during liver regeneration remains unknown. In this study, a role of HIF‐1α was experimentally elucidated in relation to sinusoidal endothelial reconstruction during liver regeneration.

Methods: Expression of HIF‐1α was evaluated in the regenerating liver following 70% hepatectomy in rats. Expressions of nuclear HIF‐1α, vascular endothelial growth factor (VEGF) and fms‐like tyrosine kinase‐1 (flt‐1) were measured by Western blot and liver blood flow by a laser Doppler. Sinusoidal endothelial cell area (SECA) and HIF‐1α were localized by immunohistochemistry. HIF‐1α mRNA was measured by reverse transcription‐polymerase chain reaction.

Result: Liver blood flow and SECA were lowest 36 and 72 h following hepatectomy, respectively. Nuclear HIF‐1α peaked at 24 h and continuously increased 72–120 h following hepatectomy. This transition was fully supported by histological HIF‐1α expression and HIF‐1α mRNA up‐regulation. VEGF and flt‐1 peaked at 120 and 12 h, respectively.

Conclusions: A significant evaluation in HIF‐1α expression was revealed in regenerating rat livers. HIF‐1α expression was preceded by VEGF and flt‐1 expression and thus may be related to sinusoidal endothelial reconstruction.
Endocannabinoids and liver disease – review
Authors: Gabbay Ezra , Avraham Yosefa , Ilan Yaron , Israeli Eran , Berry Elliot M.
Published: September 2005

Abstract:
Aims: Endocannabinoids are endogenous compounds that bind to the same receptors as tetrahydrocannabinol, the active component in marijuana and hashish. They have been found to have many physiological and patho‐physiological functions, including mood alteration, control of feeding and appetite, motor and co‐ordination activities, analgesia, immune modulation and gut motility. In this review we aim to elucidate current knowledge as to their role in liver physiology and disease.

Methods: The major findings published to date concerning endocannabinoids and liver disease are described, and their implications with regard to understanding disease mechanisms, and the development of new treatments is considered.

Results: Recently, endocannabinoids have been implicated in the hemodynamic alterations occurring in cirrhosis. These changes appear to be mediated via specific cannabinoid receptors (CB1) on splanchnic and hepatic vascular endothelium. Plasma levels of endocannabinoids also seem to be elevated in hepatitis, and are involved in apoptosis of hepatocytes by a membrane mechanism not related to a specific receptor. Other studies suggest a beneficial role for cannabinoids in reducing the inflammation of experimental hepatitis. In an animal model of acute hepatic failure, both endocannabinoids and the antagonist to the CB1 receptor have been found to have a beneficial effect on neurological and cognitive function.

Conclusions: Endocannabinoids appear to be involved in several aspects of acute and chronic liver disease, including vascular changes, modulation of inflammatory process and neurological function, Further research may provide new insights into the pathophysiology of liver disease, as well as a basis for novel treatment modalities.
EXOGENOUS ALKALINE PHOSPHATASE ACTIVITY OF ALGAL CELLS DETERMINED BY FLUORIMETRIC AND FLOW CYTOMETRIC DETECTION OF SOLUBLE ENZYME PRODUCTS (4‐METHYL‐UMBELLIFERONE, FLUORESCEIN)1
Authors: Bruckmeier Bernhard , Eisenmann Heinrich , Beisker Wolfgang , Simon Ute , Steinberg Christian E. W.
Published: September 2005

Phosphate acquisition in algae is an important process in ecosystem development. To explore exogenous alkaline phosphatase activity, a laboratory culture of Chlamydomonas reinhardtii Dangeard was investigated by fluorometric and cytometric techniques. Two fluorogenic substrates, 4‐methyl‐umbelliferone‐phosphate (MUP) and 3,6‐fluorescein‐diphosphate, were applied to examine induction of phosphorus regeneration as well as enzyme dynamics in P‐starved cells. Fluorometric analysis revealed the absence of constitutive or secretory phosphatases but traced the induction of surface‐bound exogenous phosphatases with a cellular Km of 52 μM MUP. In cytometric assays, single‐cell phosphate acquisition was examined. Exogenous phosphatase activity was detectable from cell halos and recorded continuously as the slope on fluorescence increase and cellular steady state of fluorochrome production. An experimental time course on P‐starvation indicated the induction of a phosphatase system after 4 days. The use of flow cytometry in combination with specific fluorogenic substrates is a valuable tool for fine‐tuned single‐cell analysis of phosphatase activity in algal communities.
Population Structure in the Mediterranean Basin: A Y Chromosome Perspective
Authors: Capelli C. , Redhead N. , Romano V. , Calì F. , Lefranc G. , Delague V. , Megarbane A. , Felice A. E. , Pascali V. L. , Neophytou P. I. , Poulli Z. , Novelletto A. , Malaspina P. , Terrenato L. , Berebbi A. , Fellous M. , Thomas M. G. , Goldstein D. B.
Published: September 2005

The Mediterranean region has been characterised by a number of pre‐historical and historical demographic events whose legacy on the current genetic landscape is still a matter of debate. In order to investigate the degree of population structure across the Mediterranean, we have investigated Y chromosome variation in a large dataset of Mediterranean populations, 11 of which are first described here. Our analyses identify four main clusters in the Mediterranean that can be labelled as North Africa, Arab, Central‐East and West Mediterranean. In particular, Near Eastern samples tend to separate according to the presence of Arab Y chromosome lineages, suggesting that the Arab expansion played a major role in shaping the current genetic structuring within the Fertile Crescent.
Retigabine: Bending Potassium Channels to Our Will
Authors: Lagrange Andre
Published: September 2005

The New Anticonvulsant Retigabine Favors Voltage-dependent Opening of the Kv7.2 (KCNQ2) Channel by Binding to Its Activation Gate

Wuttke TV, Seebohm G, Bail S, Maljevic S, Lerche H

Mol Pharmacol 2005;67:1009–1017

Retigabine (RTG) is an anticonvulsant drug with a novel mechanism of action. It activates neuronal KCNQ-type K+ channels by inducing a large hyperpolarizing shift of steady-state activation. To identify the structural determinants of KCNQ channel activation by RTG, we constructed a set of chimeras by using the neuronal KV7.2 ( KCNQ2) channel, which is activated by RTG, and the cardiac KV7.1 ( KCNQ1) channel, which is not affected by this drug. Substitution of either the S5 or the S6 segment in KV7.2 by the respective parts of KV7.1 led to a complete loss of activation by RTG. Trp236 in the cytoplasmic part of S5 and the conserved Gly301 in S6 (KV7.2), considered as the gating hinge (Ala336 in KV7.1), were found to be crucial for the RTG effect: mutation of these residues could either knock out the effect in KV7.2 or restore it partially in KV7.1/KV7.2 chimeras. We propose that RTG binds to a hydrophobic pocket formed upon channel opening between the cytoplasmic parts of S5 and S6 involving Trp236 and the channel's gate, which could well explain the strong shift in voltage-dependent activation.
Cytokines: A Link between Fever and Seizures
Authors: Mazarati Andrey M.
Published: September 2005

Interleukin-1β Contributes to the Generation of Experimental Febrile Seizures

Dube C, Vezzani A, Behrens M, Bartfai T, Baram TZ

Ann Neurol 2005;57:152–155

Fever can provoke “febrile” seizures (FSs). Because complex FSs may promote development of temporal lobe epilepsy, understanding their mechanisms is clinically important. By using an immature rodent model and transgenic technology, we examined the role of interleukin-1 β, (IL-1 β), a pyrogenic, proinflammatory cytokine, in FSs. IL-1 β receptor–deficient mice were resistant to experimental FSs. This resistance appeared independent of genetic background and was attributed to lack of IL-1 β signaling, because exogenous cytokine reduced the seizure threshold in wild-type but not receptor-deficient mice, independent of strain. In addition, high IL-1 β doses induced seizures only in IL-1 β receptor-expressing mice. These data indicate that IL-1 β signaling contributes critically to fever-induced hyperexcitability underlying FS, constituting a potential target for their prevention.
Contributions to the Piezoelectric Effect in Ferroelectric Single Crystals and Ceramics
Authors: Damjanovic Dragan
Published: September 2005

The piezoelectric effect in ferroelectric single crystals and ceramics is investigated considering intrinsic (lattice), and extrinsic (originating mainly from displacement of domain walls) contributions. The focus of the study of intrinsic properties is on piezoelectric anisotropy, which was examined using the Landau–Ginsburg–Devonshire phenomenological theory. It is shown that the enhanced piezoelectric response along nonpolar directions, observed in many perovskite systems, is a consequence of the flattening of the Gibbs free energy profile. This flattening is common for temperature‐, composition‐, and external field‐induced enhancement of the piezoelectric properties along nonpolar axes. A brief review of recent advances in understanding the origins of the piezoelectric nonlinearity, hysteresis, and frequency dispersion is also given.
The histological analysis, colorimetric evaluation, and chemical quantification of melanin content in ‘suntanned’ fish
Authors: Adachi Kohsuke , Kato Keitaro , Wakamatsu Kazumasa , Ito Shosuke , Ishimaru Katsuya , Hirata Takashi , Murata Osamu , Kumai Hidemi
Published: September 2005

Human melanocytes respond to UV irradiation by increasing the synthesis of melanin. While much is now understood of the pathways governing this process and the nature of the melanin synthesized, little is known of melanins produced by lower vertebrates and their capacity to respond to UV. Here we report that a fish, red seabream, can undergo ‘suntanning’. Histological, colorimetric and chemical assays were performed for suntanned red seabream fish bred in net cages to analyse the melanins and compared with shaded or wild red seabream fish. For color evaluation, the L* values of suntanned fish were dramatically lower than those in the other two groups. Pyrrole‐2,3,5‐tricarboxylic acid (PTCA), an indicator of eumelanin, was detected in suntanned fish at five times higher levels than in shaded or wild fish while 4‐amino‐3‐hydroxyphenyl‐alanine (4‐AHP), a marker for pheomelanin, could not be detected in any of the samples. Histological analysis showed that melanocytes in the suntanned skin enlarged and increased in number to form a monolayer at the surface of the skin. Analysis of L* values and PTCA levels showed quite a high correlation coefficient (r = −0.843). When comparing shaded and wild red seabream fish, the scores were closer but some significant differences were still found in some body areas. These results indicate that eumelanin accumulates in suntanned fish during the increase in skin color, which is induced by sunlight, presumably by ultraviolet radiation.
Expression of human β‐defensin‐3 in gingival epithelia
Authors: Lu Qian , Samaranayake Lakshman P. , Darveau Richard P. , Jin Lijian
Published: September 2005

Objective:  This study aimed to investigate the expression patterns of the newly discovered human β‐defensin‐3 (hBD‐3) in human gingiva.

Background:  Human β‐defensins (hBDs) are a group of small, broad‐spectrum, cationic antimicrobial peptides. Our recent study showed that the expression levels of hBD‐1 and 2 peptides were associated with periodontal conditions.

Methods:  A total of 49 gingival biopsies were collected, including 33 samples from 21 patients with chronic periodontitis and 16 samples from 16 periodontally healthy subjects. The expression of hBD‐3 was detected by immunohistochemistry and in situ hybridization. Double staining was undertaken to identify hBD‐3 peptide‐positive cells, using CD‐1a and cytokeratin 20 as markers for Langerhans cells and Merkel cells, respectively.

Results:  hBD‐3 peptide was detected in 88% of the samples, which was confined to the gingival epithelia. In healthy control subjects, hBD‐3 peptide was more frequently detected in the basal layer as compared to the patients (53% vs. 18%, p < 0.05). In patients, hBD‐3 expression extended from the basal layer to the spinous layers (82%), in which hBD‐3 was confined to the basal and deep spinous layers in clinically healthy tissues from patients, whereas it extended to the superficial spinous layers in pocket tissues from patients (0% vs. 50%, p < 0.05). In both groups, hBD‐3 peptide was expressed not only in gingival keratinocytes, but also in Langerhans cells and Merkel cells. hBD‐3 transcripts were detected in 90% of the samples and they were confined to the basal and/or suprabasal layers of gingival epithelia.

Conclusions:  This study shows that hBD‐3 is frequently expressed in gingival epithelia. The appropriate expression of hBD‐3 peptide may contribute to the maintenance of periodontal homeostasis, possibly through its antimicrobial effect and promotion of adaptive immune responses.
COMPARISON OF FLUID‐ATTENUATED INVERSION RECOVERY AND T2‐WEIGHTED MAGNETIC RESONANCE IMAGES IN DOGS AND CATS WITH SUSPECTED BRAIN DISEASE
Authors: Benigni Livia , Lamb Christopher R.
Published: September 2005

To compare fluid‐attenuated inversion recovery (FLAIR) and T2‐weighted magnetic resonance (MR) imaging in small animal patients with suspected brain disease, paired sets of FLAIR and T2‐weighted MR images of 116 dogs and cats were reviewed separately without any patient information. Images were rated as normal or abnormal using a five‐point scale, and the distribution, signal intensity, and anatomic location of abnormalities were recorded. In 60 animals, both FLAIR and T2‐weighted images were normal. In 50 animals, the same abnormalities were identified in both FLAIR and T2‐weighted images. Overall, very good agreement was found between FLAIR and T2‐weighted MR images (κ=0.88). FLAIR images had abnormalities that were not recognized in the corresponding T2‐weighted images in six of 116 examinations (5%). In four of these, the abnormalities in FLAIR images were thought to represent pathology, including granulomatous meningoencephalitis in one dog, postictal edema in one dog, and undiagnosed lesions in two dogs. In the remaining two examinations, the abnormalities in FLAIR images were probably artifacts. No examples were found of intracranial abnormalities in T2‐weighted images that were not visible in FLAIR images. In this study, acquiring FLAIR images in addition to T2‐weighted images resulted in detection of otherwise occult abnormalities in relatively few patients.
ULTRASONOGRAPHIC ANATOMY OF THE CANINE ELBOW
Authors: Lamb Christopher R. , Wong Kenneth
Published: September 2005

To produce detailed ultrasonographic images of the soft tissue structures around the canine elbow joint, a series of greyhound cadaver limbs were scanned both intact and dissected in a water bath. Suitable transducer positions and bone landmarks are described and the ultrasonographic appearance of the lateral collateral ligament, anconeal process, triceps tendon, origin of olecranon ligament, biceps tendon insertion, medial collateral ligament, and medial coronoid process are illustrated. Improved understanding of the anatomy of the canine elbow will support clinical ultrasonography of this region.
ULTRASONOGRAPHIC ANATOMY OF THE NORMAL CANINE CALCANEAL TENDON
Authors: Lamb Christopher R. , Duvernois Alice
Published: September 2005

To provide a series of detailed ultrasonographic images of the canine calcaneal tendon, greyhound cadaver pelvic limbs were scanned with a high‐resolution transducer, and images compared with dissected specimens. The three components of the calcaneal tendon are the tendons of insertion of the gastrocnemius, superficial digital flexor, and a conjoined tendon formed by tendons from the biceps femoris, semitendinosus, and gracilis. Each of these three tendons was visible in transverse ultrasound images, each measuring 2.4–3.2‐mm thick at mid‐calcaneal tendon. Improved understanding of the anatomy of the calcaneal tendon will support clinical ultrasonography of this region.
EVALUATION OF THE ABDOMEN USING ULTRASOUND FOLLOWING A VENTRAL MIDLINE CELIOTOMY
Authors: Weinstein Jeff , Beck Kerri , Quinn Mary , Jessen Carl
Published: September 2005

Over the last 20 years, ultrasound has become a useful diagnostic tool in veterinary medicine. The purpose of this study was to use ultrasonographic examinations to determine if intra‐abdominal contents could be visualized. Nineteen dogs, ranging from 8 months to 18 years of age were included. Each animal was evaluated sonographically prior to surgery, 24 h after surgery, and then 2–6 weeks following the surgical procedure. The results of our study suggest that ultrasound is an effective means for evaluation of the abdomen and surgery site following surgery. Both the abdomen and surgery site were clearly visualized in all dogs. In addition, subjective evaluation of the intra‐abdominal contents was performed. The limiting factor in this study was not the presence of air, as was expected. Rather the limiting factor for appropriate visualization was pain. The information obtained could prove to be useful to surgeons and radiologists in assessing a patient's status postoperatively.
Thiol reducing compounds prevent human amylin‐evoked cytotoxicity
Authors: Konarkowska Barbara , Aitken Jacqueline F , Kistler Joerg , Zhang Shaoping , Cooper Garth J S
Published: September 2005

Human amylin (hA) is a small fibrillogenic protein that is the major constituent of pancreatic islet amyloid, which occurs in most subjects with type‐2 diabetes mellitus (T2Dm). There is growing evidence that hA toxicity towards islet β‐cells is responsible for their gradual loss of function in T2Dm. Preventing hA‐mediated cytotoxicity has been proposed as a route to halt the progression of this disease, although this has not yet been demonstrated in vivo. The aim of our studies, in which we show that a small number of hA‐treated cells exhibit intracellular accumulation of reactive oxygen species (ROS), was to evaluate the role of oxidative stress in the mechanism of hA‐mediated cytotoxicity. Here we report that catalase and n‐propyl gallate, antioxidants that are thought to act mainly as free radical scavengers, afford RINm5F cells only limited protection against hA‐mediated toxicity. By contrast, the thiol antioxidants, N‐acetyl‐L‐cysteine (NAC), GSH and dithiothreitol, which not only react with ROS, but also modulate the cellular redox potential by increasing intracellular levels of GSH and/or by acting as thiol reducing agents, afford almost complete protection and inhibit the progression of hA‐evoked apoptosis. We also show that hA treatment is not associated with changes in intracellular GSH levels and that inhibition of GSH biosynthesis has no effect on either hA‐mediated cytotoxicity or NAC‐mediated protection. These results indicate that, in addition to the induction of oxidative stress, hA appears to mediate cytotoxicity through signalling pathways that are sensitive to the actions of thiol antioxidants.
The Effects of Component Variables on Performance in Graph Comprehension Tests
Authors: Attalim Yigal , Goldschmidt Chanan
Published: September 2005

Some cognitive characteristics of graph comprehension items were studied, and a model comprised of several variables was developed. 132 graph items of the Psychometric Entrance Test were included in the study. By analyzing the actual difficulty of the items, an evaluation of the impact of the cognitive variables on item difficulties could be made. Results indicate that successful prediction of item difficulty can be calculated on the basis of a wide range of item characteristics and task demands. This suggests that items can be screened for processing difficulty prior to being administered to examinees. However, the results also have implications for test validity in that the various processing variables identified involve distinct ability dimensions.
Flawed Items in Computerized Adaptive Testing
Authors: Potenza Maria T. , Stocking Martha L.
Published: September 2005

Educational Testing Service A multiple‐choice test item is identified as flawed if it has no single best answer. In spite of extensive quality control procedures, the administration of flawed items to test takers is inevitable. A limited set of common strategies for dealing with flawed items in conventional testing, grounded in the principle of fairness to examinees, is reexamined in the context of adaptive testing. An additional strategy, available for adaptive testing, of retesting from a pool cleansed of flawed items, is compared to the existing strategies. Retesting was found to be no practical improvement over current strategies.
The prolactin responses to active and passive heating in man
Authors: Low David , Purvis Alison , Reilly Thomas , Cable N. Tim
Published: September 2005

The aim of this study was to compare the prolactin and blood pressure responses at identical core temperatures during active and passive heat stresses, using prolactin as an indirect marker of central fatigue. Twelve male subjects cycled to exhaustion at 60% maximal oxygen uptake () in a room maintained at 33°C (active). In a second trial they were passively heated (passive) in a water bath (41.56 ± 1.65°C) until core temperature was equal to the core temperature observed at exhaustion during the active trial. Blood samples were taken from an indwelling venous cannula for the determination of serum prolactin during active heating and at corresponding core temperatures during passive heating. Core temperature was not significantly different between the two methods of heating and averaged 38.81 ± 0.53 and 38.82 ± 0.70°C (data expressed as means ±s.d.) at exhaustion during active heating and at the end of passive heating, respectively (P> 0.05). Mean arterial blood pressure was significantly lower throughout passive heating (active, 73 ± 9 mmHg; passive, 62 ± 12 mmHg;P< 0.01). Despite the significantly reduced blood pressure responses during passive heating, during both forms of heating the prolactin response was the same (active, 14.9 ± 12.6 ng ml−1; passive, 13.3 ± 9.6 ng ml−1; n.s.). These results suggest that thermoregulatory, i.e. core temperature, and not cardiovascular afferents provide the key stimulus for the release of prolactin, an indirect marker of central fatigue, during exercise in the heat.
Mechanism of chloride permeation in the cystic fibrosis transmembrane conductance regulator chloride channel
Authors: Linsdell Paul
Published: September 2005

The cystic fibrosis transmembrane conductance regulator (CFTR) functions as a Cl− channel important in transepithelial salt and water transport. While there is a paucity of direct structural information on CFTR, much has been learned about the molecular determinants of the CFTR Cl− channel pore region and the mechanism of Cl− permeation through the pore from indirect structure–function studies. The first and sixth transmembrane regions of the CFTR protein play major roles in forming the channel pore and determining its functional properties by interacting with permeating Cl− ions. Positively charged amino acid side‐chains are involved in attracting negatively charged Cl− ions into the pore region, where they interact briefly with a number of discrete sites on the pore walls. The pore appears able to accommodate more than one Cl− ion at a time, and Cl− ions bound inside the pore are probably sensitive to one another's presence. Repulsive interactions between Cl− ions bound concurrently within the pore may be important in ensuring rapid movement of Cl− ions through the pore. Chloride ion binding sites also interact with larger anions that can occlude the pore and block Cl− permeation, thus inhibiting CFTR function. Other ions besides Cl− are capable of passing through the pore, and specific amino acid residues that may be important in allowing the channel to discriminate between different anions have been identified. This brief review summarizes these mechanistic insights and tries to incorporate them into a simple cartoon model depicting the interactions between the channel and Cl− ions that are important for ion translocation.
An elementary derivation of E=m
c2
Authors: Rohrlich Fritz
Published: September 2005

The equality E=mc2 is derived in a fashion suitable for presentation in an elementary physics course for nonscience majors. It assumes only 19th-century physics and knowledge of the photon.
Rigid levitation and suspension of high-temperature superconductors by magnets
Authors: Brandt E. H.
Published: September 2005

A high-Tc superconductor floating freely above a magnet of low symmetry remains rigidly suspended in the air in almost any position and orientation as if stuck in an invisible heap of sand. This striking effect is due to pinning of the magnetic flux lines inside the superconductor and is often overlooked, since usually magnets with rotational symmetry are used for levitation. Magnets with rotational symmetry allow for nearly undamped orbiting and rotation of the superconductor about the magnet’s symmetry axis. But even in this geometry, flux-line pinning can be seen, since it forces the orbiting superconductor to turn the same face toward the axis. Superconductors with sufficiently strong pinning may even be suspended below a magnet.
Undergraduate laboratory experiment: Measurement of the complex refractive index and the band gap of a thin film semiconductor
Authors: Mártil I. , Díaz G. González
Published: September 2005

A simple experiment to determine the complex refractive index of a semiconductor in thin film form through transmittance measurements is presented. The experiment allows us to obtain, from the real part of the refractive index, the n dispersive law, and from the imaginary part, the absorption coefficient α. An energy dependence analysis of α is done to obtain the semiconductor band gap value and the nature of the optical transition (direct or indirect). Transmittance data of a CdS thin semiconductor film have been analyzed, and a value for the real part of the refractive index, which is very similar to the bulk value, has been obtained. Also, from the absorption coefficient a band gap value of (2.33±0.02) eV for CdS is deduced, in agreement with previously published values.
Enriching Elementary Quantum Mechanics with the Computer: Self-Consistent Field Problems in One Dimension
Authors: Bolemon Jay S. , Etzold David J.
Published: September 2005

The use of a computer in undergraduate physics courses opens the door to a large number of instructive problems which were once precluded due to the necessity of numerical analysis. One such example for elementary quantum mechanics is the problem of a bound system of more than two particles which may be solved by the method of the self-consistent field (SCF). This paper discusses one-dimensional systems of particles whose solutions are obtained by the SCF method using the Hartree approximation. The procedure is shown to be a simple extension of programs which many undergraduates already use to obtain computer solutions of the Schrödinger equation in one dimention. Calculations for these systems serve as a useful introduction to iterative techniques, and the results provide the student with insight into the nature of atomic calculations for multi-electron atoms.
Linear Momentum Conservation in a Nonconservative Environment
Authors: Finn Edward J.
Published: September 2005

An experiment is described for the general physics laboratory where metal cylinders slide, with acceleration, down an inclined metal track and out onto a horizontal track. The apparatus is quite primitive and readily fabricated from easily available materials. After the coefficient of friction is calculated through energy considerations, the conservation of momentum and Q-value for elastic and inelastic collisions is investigated. The masses of the cylinders and various distances are the only measurements necessary. In this case where friction must not be ignored, the experiment has been found stimulating to beginning students and the results satisfactory, particularly when the collision is made totally inelastic (a capture reaction).
Measuring q/m for Water Drops—An Introduction to the Effects of Electrical Forces
Authors: Hart Francis X.
Published: September 2005

The charge-to-mass ratio of charged, freely-falling water drops is measured in two ways: from their deflection in a horizontal electric field and from the total charge delivered by a large number of drops to a Faraday cup. The apparatus needed is simple and inexpensive. The data analysis requires the combined use of several concepts generally encountered separately. Suitable choice of parameters allows the study of (1) one-dimensional uniform acceleration, (2) two-dimensional uniform acceleration, or (3) uniform horizontal but non-uniform vertical acceleration.
Natural Units: Are They for Everybody?
Authors: Bartlett D. F.
Published: September 2005

The International System of Units (SI) is becoming accepted, but a different system may be more convenient, more coherent, and more conducive to communication between scientist and layman.
Energy Density and Current in Quantum Theory
Authors: Mathews W. N.
Published: September 2005

The concepts of energy density and energy current density for a single particle in nonrelativistic quantum theory are discussed. It is shown that the energy density ε and the energy current density Q are related by the equation (δε/δt)+∇·Q = S, where S represents external power sources.
Laboratory Experiment in Semiconductor Surface-Field Effects
Authors: Goodman F. R. , Heald D. L. , Neville R. C.
Published: September 2005

A laboratory instructional program involving metal-insulator-semiconductor (MIS) devices is described. At the University of California, Santa Barbara (UCSB), this program has been used to teach the theory and applications of semiconductor surface field effects. A two-part laboratory experiment is described. In the first part, students become familiar with the important parameters of a simple MIS device and learn measurement techniques. In the second part, device fabrication procedures are learned and supported by measurement techniques mastered in the first part. As an upper-division or first-year graduate laboratory experiment, this program is found to be an excellent way of introducing students to independent experimentation.
Statistical Analysis of Classical Few-Particle Systems
Authors: Olness R. J. , Hoover W. G.
Published: September 2005

The three examples of ideal gas, square well, and harmonic oscillator particles illustrate the equivalence of the constant-energy and constant-temperature descriptions of statistical mechanics if the number of degrees of freedom is large. Significant differences between these descriptions appear, however, in the opposite extreme, i.e., the few-particle limit. The analysis presented here supports the conclusion that three degrees of freedom are necessary to localize a particle in the oscillator potential. This result is discussed in connection with the stability (finite rms particle displacement) of three-dimensional harmonic crystals.
Science and Society Test for Scientists: The Energy Crisis
Authors: Hafemeister David
Published: September 2005

A “Science and Society Test” which deals with questions (and the author's answers) of the “energy crisis” is presented. The test stresses back-of-the-envelope questions which most academic scientists who have had sophomore physics should be able to answer. Such topics as laser fusion, emergency core cooling, solar sea power, urban transportation, radioactive wastes in Antarctica, isotope separation with laser, etc., are covered in the questions. It is suggested here that a question-answer format can be used to transmit science and society subject matter more effectively than sophisticated computer calculations.
Discussion of Møller on the clock paradox
Authors: Giannoni Carlo
Published: September 2005

Møller's analysis of the clock paradox in The Theory of Relativity is reformulated using Møller's mathematical formalism but comparing adjacent unresynchronized natural clocks rather than coordinate clocks. The relative behavior of natural clocks in the two systems is seen to depend in the first instance on their initial synchronization, but regardless of initial synchronization, on the return trip the “rest” clock is shown to experience a uniform and continuous increase in time relative to adjacent “moving” clocks. There is no sudden, discontinuous increase when using unresynchronized natural clocks as there is when using coordinate clocks.
Transfer of Learning and the Conservation Laws
Authors: Smith Frank A. , Schmuckler Joseph S.
Published: September 2005

An educational experiment involving the transfer of learning and the conservation laws of physics was conducted at West Chester State College. Four hundred nonscience students were divided into experimental and control groups. The students in the experimental group studied the laws of the conservation of baryons, leptons, and electric charge by means of programmed instruction, while the students in the control group studied a topic unrelated to the conservation laws, also by means of programmed instruction. At a later time, both groups studied the conservation of momentum by means of programmed instruction. Two trials of the experiment were conducted and in both trials the students in the experimental group completed the momentum program in less time and scored higher on a test on the conservation of momentum than students in the control group.
Interpretation of Instantaneous Frequencies
Authors: Mandel L.
Published: September 2005

The relation between instantaneous frequencies and Fourier components of a time-dependent signal is examined. Examples are given in which large excursions of the instantaneous frequency do not correspond to any Fourier components, and in which Fourier components are not manifest in the instantaneous frequencies. It is shown that, while the appropriately weighted first moments of the component frequency and the instantaneous frequency coincide, the same is not true of the higher moments. There is no one-to-one relationship between the two frequencies which correspond to different measurements. These considerations may be important in the study of resonant interactions between atoms and electromagnetic fields.
The Application of Noether's Theorem to Optical Systems
Authors: Blaker J. Warren , Tavel Morton A.
Published: September 2005

Noether's theorem has proved an invaluable aid in deriving conservation laws from theories which can be expressed in variational form. The article exploits this fact, deriving Snell's law and the Smith-Helmholtz invariant of optics by the rather unusual means (for optics) of applying Noether's theorem to the invariances of the optical Lagrangian. This derivation of these well-known results makes use of the symmetry properties of the optical system without specific reference to its elements.
Velocity-Dependent Nuclear Forces and Weber's Electrodynamics
Authors: Pearson J. M. , Kilambi Alamelu
Published: September 2005

It is pointed out that the p2 forces of nuclear physics are structurally similar to the force postulated by Weber in pre-Maxwellian times to be acting between moving electric charges. A brief review of the essential features of the Weber force is accordingly presented, with particular emphasis being placed on the fact that although it is incorrect as a basis for electrodynamics it nevertheless leads to the correct expressions for the force and torque acting between closed circuits. It is in this way that we can understand the quasi-electromagnetic character of certain effects that arise in nuclear scattering in the presence of velocity-dependent forces.
Perturbation Treatment for Two-Particle Symmetrized Systems with Interactions
Authors: Doty Duane R. , Einstein Stewart A.
Published: September 2005

Perturbation of a simple two particle system is briefly reviewed in one dimension leading to symmetrization of the total system's wave function for the case of identical non-interacting particles. The results of admitting some mutual particle interactions are studied by observing changes in the total system's wave function. For the case of hard-core interactions the effects on the system's symmetry properties are computed.
Dispersion Relations for Optically Active Media
Authors: Healy W. P. , Power E. A.
Published: September 2005

The simple well-known form of the Kramers-Krönig dispersion relation that connects the real part of the refractive index with the absorption coefficient in a medium must be modified if the medium is optically active. It is most enlightening to make the correct generalization because the point of departure from the derivation of the conventional dispersion relation involves the subtle analysis of crossing symmetry used mostly in high energy particle physics. An interrelation between the very familiar physical theory for the refractive index of a dilute medium and crossing symmetry is clearly of pedagogical interest especially so when the phenomena involved are basic tools in chemistry, namely optical activity and circular dichroism. The modified dispersion relation leads to the correct relationship between the optical rotary power and the differential absorption in circular dichroism for the medium. Finally it is shown that the Rosenfeld-Condon expression for optical rotary power follows from a sharp line approximation for the absorption coefficients.
Presenting the Planck's Relation E = nhν
Authors: Ram Budh
Published: September 2005

The theoretical discussion of the spectral distribution of black-body radiation is presented in a manner in which one “derives” the Planck relation E = nhν starting with the Planck radiation formula as empirically given. The presentation emphasizes the importance of experiment, and deductive and inductive reasoning in scientific research.