bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of tonsillectomy in adult sleep apnea syndrome
Authors: MIYAZAKI SOICHIRO , ITASAKA YOSHIAKI , TADA HIROYUKI , ISHIKAWA KAZUO , TOGAWA KIYOSHI
Published: March 2008

Abstract Tonsillectomy was performed on 10 adult sleep apnea patients (five males, five females; average age, 39 years old; average body mass index, 24.8 kg/m2). Tonsillectomy alone was indicated if tonsillar hypertrophy was moderate to severe and the length of the soft palate was less than 35 mm according to cephalometry. Remarkable improvements were observed in all cases following surgery. The average weight of the resected tonsils was 11 g. The patients demonstrated a preoperative apnea + hypopnea index (AHI) of 14.4/h. This decreased to 2.9/h postoperatively. The intraesophageal pressure change improved from ‐36.6 to ‐15.7 cmH2O following surgery. A significant correlation between preoperative AHI and the degree of obesity (r= 0.684, P < 0.05) was found. Although uvulopalatopharyngoplasty has been used extensively to treat sleep apnea, the present results suggests that certain subjects can be effectively treated through only tonsillectomy.
Mechanism of action and therapeutic indication of prosthetic mandibular advancement in obstructive sleep apnea syndrome
Authors: ISHIDA MASAE , INOUE YUICHI , SUTO YUJI , OKAMOTO KAZUMI , RYOKE KAZUO , HIGAMI SHIGERU , SUZUKI TAKEO , KAWAHARA RYUZO
Published: March 2008

Abstract Prosthetic mandibular advancement (PMA) was applied to nine patients with obstructive sleep apnea syndrome (OSAS) and its therapeutic usefulness, mechanism of action, and clinical indication were discussed based on polysomnographic findings and serial examination of upper airway before and during PMA treatment. Apnea hypopnea index significantly decreased during PMA treatment compared with the value before treatment (P < 0.01) and the rate of the treatment responder counted 78.1%. Cephalometric variables indicated forward and inferior advancement of mandible in our subjects. Magnetic resonance imaging of the upper airway during sleep revealed a marked improvement of velopharyngeal obstruction in most subjects. In addition, intraesophageal negative pressure during sleep decreased significantly. Our results confirmed the high therapeutic efficacy of PMA for OSAS and indicated forward advancement of the mandible and decrease of negative pressure loading on upper airway with PMA might suppress velopharyngeal collapse. Thus, PMA was regarded as one of the treatments of choice for OSAS occurring based on with velopharyngeal narrowing.
Prevalence of sleep‐related respiratory disorders in 101 schizophrenic inpatients
Authors: TAKAHASHI KEN‐ICHI , SHIMIZU TETSUO , SUGITA TOSHIO , SAITO YASUSHI , TAKAHASHI YUJI , HISHIKAWA YASUO
Published: March 2008

Abstract We studied the prevalence of sleep‐related respiratory disorders (SRRD) in 101 schizophrenic inpatients (64 men and 37 women) and in 48 healthy volunteers (control group:22 men and 26 women) using ambulatory pulse‐oximetric devices. Those with a desaturation index (DI) 5 were classified as having SRRD. The prevalence of SRRD in the schizophrenic patients (men 21.9%, women 13.5%) was not higher than that in the control group (men 30.7%, women 13.6%). Gender difference in the prevalence of SRRD was not observed in schizophrenic group. This was probably because the schizophrenic women took an increased amount of sleeping pills. Neuroleptics were shown to be least effected on SRRD.
Two cases of sleep‐disordered breathing in climacteric
Authors: WATANABE TAKUYA , MIKAMI AKIRA , MOTONISHI MASAMICHI , HONDA HIDEHARU , KYOTANI KYOKO , URUHA SHIGEHIKO , TERASHIMA KIYOJI , TESHIMA YOSHIO , SUGITA YOSHIRO
Published: March 2008

Abstract Two cases of sleep disordered‐breathing in climacteric were reported. Polysomnography including esophageal pressure (Pes) measurement was performed. Case 1 was diagnosed as upper airway resistance syndrome. Case 2 was diagnosed as obstructive sleep apnea syndrome, while many episodes of upper airway resistance also existed. Hormone replacement therapy improved clinical symptoms, and in case 1, Pes nadir was improved but incidence of arousals which was induced by breathing disturbances was not significantly changed. Sleep disordered‐breathing should be suspected as a cause of sleep disorder even in females, especially in climacteric age. Pes measurement and evaluation of arousals is required. Hormone replacement therapy may release the upper airway resistance.
Sleep‐disordered breathing in a patient with congenital myopathy
Authors: TAKAHASHI YUJI , SHIMIZU TETSUO , TAKAHASHI KENICHI , SAITO YASUSHI , OGAWA YURIKO , KANBAYASHI TAKASHI , HISHIKAWA YASUO
Published: March 2008

Abstract A case of adult onset myopathy who showed a peculiar sleep‐related respiratory disorder (SRRD) is reported. She recovered from respiratory failure after tracheostomy and/or with the aid of the respirator used only during the night. Sleep study without the use of respirator revealed that her sleep was highly fragmented by frequent arousal responses due to inspiratory effort but not by apnea or hypopnea. To our knowledge this type of SRRD has not been described.
Clinical characteristics of circadian rhythm sleep disorders
Authors: KAMEI YUICHI , URATA JUJIRO , UCHIYAYA MAKOTO , HAYAKAWA TATSURO , OZAKI SHIGERU , SHIBUI KAYO , OKAWA MASAKO
Published: March 2008

Abstract From our practice at the sleep disorders clinic in Kohnodai Hospital, National Center of Neurology and Psychiatry (NCNP), we report the clinical characteristics of circadian sleep‐wake rhythm disorders. Nearly 90% of circadian rhythm sleep disorders were diagnosed as delayed sleep phase syndrome (DSPS) or as non‐24 sleep‐wake syndrome (non‐24). While DSPS was equally common in males and females, non‐24 was more frequently seen in men. It was of psychiatric interest that a considerable number of patients had depressive states in the course of their circadian rhythm sleep disorders. Difficulty in adapting to social life was more severe in patients with non‐24 than in those with DSPS.
Human time production under constant routine
Authors: NAKAJIMA TORU , UCHIYAMA MAKOTO , ENOMOTO TETSURO , SHIBUI KAYO , ISHIBASHI KENICHI , KANNO OSAMU , OKAWA MASAKO
Published: March 2008

Abstract Previous reports have suggested that human time production of several seconds fluctuates across the day. In order to test whether human time production was controlled by the circadian process or by the homeostatic process, we investigate diurnal fluctuation of human time production under constant routine conditions. We found a common circadian feature in time production tests of 10 s by calculating Z‐score for each subject; afternoon troughs and morning peaks. These results may suggest that human time production was modulated by the circadian process.
Twenty‐four hour profiles of four hormones under constant routine
Authors: UCHIYAMA MAKOTO , ISHIBASHI KENICHI , ENOMOTO TETSURO , NAKAJIMA TORU , SHIBUI KAYO , HIROKAWA GO , OKAWA MASAKO
Published: March 2008

Abstract We studied the circadian features of melatonin, cortisol, thyroid stimulating hormone (TSH), and growth hormone (GH) together with rectal temperature during 36 h continuous forced wakefulness without physical exercise under dim light condition (constant routine). Subjects consisted of four healthy men aged 22–24 years. Blood sampling was conducted hourly, and food and water were supplied bi‐hourly during the constant routine. Melatonin, TSH and cortisol displayed clear circadian rhythms under constant routine condition. While GH secretion was unlikely to be driven solely by the circadian pacemaker, its suppression round BT nadir may indicate that GH secretion was modulated to some extent by circadian rhythm.
Core temperature pattern and self‐rated lifestyle
Authors: FUKUDA KAZUHIKO , ISHHARA KANEYOSHI , TAKEUCHI TOMOKA , TAKEUCHI TOMOKA , INUGAMI MAKI
Published: March 2008

Abstract We investigated the relationship between a subject's self‐rated lifestyle and their pattern of nocturnal rectal temperature. Fifty‐five students participated in the study. Among several significant findings, irregularity and eveningness component of lifestyle (irregular and delayed sleep phase) showed a significant negative correlation with temperature at the morning rising time. Examination of the nocturnal temperature pattern revealed that rectal temperature stayed at its lowest level in the early morning hours in the subjects with irregular and eveningness‐like lifestyles.
Effects of evening light on body temperature
Authors: KUBOTA TOMIO , UCHIYAMA MAKOTO , HIROKAWA GO , OZAKI SIGERU , HAYASI MITUKO , OKAWA MASAKO
Published: March 2008

Abstract Six healthy male subjects aged 21–35 years participated in the present study. The subjects were exposed to dim light (150 lux) or bright light (3000 lux) at eye level, from 19.00 to 21.30 h for 5 days. Rectal temperature and wrist activity were monitored throughout the study period. Rectal temperature nadir was delayed significantly after the bright light exposure. Ease in sleep initiation and overall sleep quality, measured by questionnaire, were aggravated significantly by the evening bright light exposure. These results suggest that strong illumination at night may disturb nocturnal sleep.
Effects of short duration morning bright light in healthy elderly subjects. I:Subjective feeling and ophthalmological examinations
Authors: FUKUDA NORIKO , KOHSAKA MASAKO , SASAMOTO YOICHI , KOYAMA EMI , KOBAYASHI RIKO , HONMA HIROSHI , MATSUBARA HOZUMI , NAKANO TOSHIO , SAKAKIBARA SATOSHI
Published: March 2008

Abstract Seven aged subjects aged 61–78 years were exposed to 6000 lx bright light for 30 min during morning hours at their homes for 1 week. Visual analog scale was recorded before bedtime and after rising to assess subjective feelings. Ophthalmological examinations were made before and after light exposure, to exclude pre‐existing ocular disorders and to detect ocular damage. Furthermore, ocular fatigue was self‐evaluated immediately before and after exposure. Visual analog scale results indicated that alertness reduced significantly before bedtime. Ophthalmological abnormalities were not found after exposure. These findings suggest that short duration morning bright light exposure reduces night‐time vigilance.
Polysomnography and body temperature changes by phototherapy in a delayed sleep phase syndrome case
Authors: WATANABE TSUYOSHI , KATO MASAAKI , SEKIMOTO MASANORI , KAJIMURA NAOFUMI , TAKAHASHI KIYOHISA
Published: March 2008

Abstract We examined polysomnography (PSG) and body temperature in a patient with delayed sleep phase syndrome who responded to phototherapy. The patient was a 31‐year‐old woman whose condition had slightly improved by a vitamin B12 administration. Phototherapy was administered to her in combination with the vitamin B12 medication, and this combined treatment successfully advanced her delayed sleep phase. On PSG, the regimen showed shortened sleep latency, decreased total sleep time and stages 1 and 2 sleep, and increased slow wave sleep. Phototherapy also improved temporal distribution of delta half‐waves (0.5‐2.0 Hz, 31 µV) as well as phase relationship between sleep and body temperature.
Wrist activity rhythm and sleep diary of delayed sleep phase syndrome
Authors: MIZUMA HIKARI , SAKAMOTO TETSURO
Published: March 2008

Abstract Wrist activity rhythm and sleep diary data in a case of delayed sleep phase syndrome were investigated. The sleep self‐estimation was nearly compatible with the activity levels of the actigraph. The actigraphic data were also analyzed. The subject's most fixed period of activity was 24.31 h, and acrophase (time of day) that fixed the data to a 24 h period was 03.25 h. The subject has had reversed night and day sleep patterns for more than 7 years. It was very difficult to advance the sleep phase when the delayed phase has been continuous long‐term under the state of poor social cues.
Melatonin treatment for circadian rhythm sleep disorders
Authors: OKAWA MASAKO , UCHIYAMA MAKOTO , OZAKI SHIGERU , SHIBUI KAYO , KAMEI YUICHI , HAYAKAWA TASTURO , URATA AND JUJIRO
Published: March 2008

Abstract We administered 1–3 mg melatonin to 11 patients (eight men, three women, aged 16–46 years) with circadian rhythm sleep disorders; nine with delayed sleep phase syndrome and two with non‐24‐hour sleep‐wake syndrome. Sleep logs were recorded throughout the study periods and actigraph and rectal temperature were monitored during treatment periods. Melatonin was administered 1–2 h before the desirable bedtime for expected phase‐shifting, or 0.5‐1 h before habitual bedtime for gradual advance expecting an hypnotic effect of the melatonin. Melatonin treatments were successful in 6/11 patients. Timing and dose of melatonin administration, together with its pharmacological properties for circadian rhythm sleep disorders, should be further studied.
Trials of bright light exposure and melatonin administration in a patient with non‐24 hour sleep‐wake syndrome
Authors: HAYAKAWA TATSURO , KAMEI YUICHI , URATA JUJIRO , SHIBUI KAYO , OZAKI SHIGERU , UCHIYAMA MAKOTO , OKAWA MASAKO
Published: March 2008

Abstract We report a patient with non‐24 h sleep‐wake syndrome (non‐24) whose free‐running sleep‐wake cycle was successfully treated with both scheduled bright light exposure and melatonin treatment. In the present study, morning bright light as well as evening melatonin phase‐advanced sleep‐wake cycles and melatonin rhythm. Both these procedures achieved appropriate entrainment to a 24 h day. However, the patient did not continue morning bright light therapy after the discharge. Rising at appropriate times in the morning for bright light therapy was difficult for him to continue. Melatonin treatment was better tolerated because of its ease of application.
Criminal and violent behavior in schizophrenic patients: An overview
Authors: MODESTIN JIRI
Published: March 2008

Abstract  An overview of the most important older and newer results regarding the relationship between violent and criminal behavior on the one hand and schizophrenic illness on the other hand is presented. Four different methods are available to study this relationship: (i) study of the prevalence of mental illness in criminal/violent populations; (ii) study of criminality/violence rate in samples of psychiatric patients; (iii) study of criminality/violence in community samples comparing mental patients with non‐patient community residents; and (iv) study of criminality/violence in birth cohorts prospectively. All these methods have been used; but samples composed of schizophrenic patients exclusively were only exceptionally studied. The results indicate that there is a modest but significant relationship between schizophrenia and violence and crime which persists even after controlling for demographic and socio‐economic variables. The probability of schizophrenic patients to be criminal or violent depends on the acuity of their illness and is increased by their use of psychoactive substances. Generally, however, violent and criminal acts directly attributable to mental illness account only for a very small proportion of such acts in the society.
European Monetary Union or competing currencies: which way for monetary integration in Europe?
Authors: CURRIE DAVID
Published: March 2008

In theAntibes in September, Mr. Laws on perplexed and irritated his fellow European finance ministers by proposing a scheme for allowing currencies to compete one against the other in Europe. It perplexed them because it was presented as a basis for proceeding towards monetary union within the European Community in accordance with the resolve of European Heads of State at the Madrid Summit, whereas it appeared as a recipe for monetary confusion, not fusion. It irritated them because it appeared to them to be yet another British manoeuvre to derail agreed progress towards greater economic and monetary integration in Europe. It especially annoyed the potential allies of the UK on this issue who regard the French and Commission attempts to push rapidly towards monetary union as ill‐advised, and who saw the Chancellor's ill‐thought out proposal as playing into their hands.

Some political commentators have suggested that Mr. Lawson was seeking to play a clever hand. He is known to favour UK entry to the Exchange Rate Mechanism of the European Monetary System, and on this is at odds with Mrs. Thatcher. Professor Alan Walters, adviser to the Prime Minister, is said to favour the idea of competing currencies in Europe. It may be that the Chancellor was not displeased to have this idea knocked down in the Antibes, leaving a strengthened EMS as the only realistic alternative to full monetary union in Europe.

Whatever the truth of this, it seems inevitable that UK opposition to ambitious proposals for European Monetary Union will be met with less sympathy in future as a result of the Antibes meeting. This is a pity. For as we suggested in the June Economic Viewpoint, there is a serious case yet to be made in favour of the idea of competing currencies. This idea need not be in conflict with the objective of exchange rate stability, so that it is not incompatible with the EMS. Competition between currencies need not mean exchange rate instability. Rather it may mean competition over responsible monetary policies, encouraging their spread within Europe. An implication is that full monetary union may not be desirable. If the UK advanced this position in Europe, it may well carry the day. In this Viewpoint, we develop this argument about the direction for further monetary integration in Europe.
Economic Policy ‐ Fact and Ambition
Authors: BALL PROFESSOR SIR JAMES
Published: March 2008

For much of the postwar period, the consensus in British macroeconomics held that output and unemployment were determined by demand which could be managed by the government. Constraints on policy were set by inflation and the balance of payments. Despite the failure of this approach in the 1970s and its rejection in favour of a less ambitious approach since 1979, there are signs that the old consensus is returning. It would be surprising if the 1990s did not produce a shift away from the more hands‐off monetarist approach towards greater intervention once again.
On the back of a motorbike: Middle‐class mobility in Ho Chi Minh City, Vietnam
Authors: TRUITT ALLISON
Published: March 2008

“Mobility” is a key concept in understanding processes of globalization and class formation. In this article, I examine motorbike mobility in Ho Chi Minh City and its role in reordering social stratification in urban Vietnam. In the years following trade liberalization, motorbikes emerged as exemplary symbols of purchasing power, displaying both monetized and motorized power. In response to the exponential increase in the number of motorbikes, Vietnamese state agencies inscribed streets with divisions to separate different classes of vehicles and regulate the flow of traffic. Motorbikes, I argue, elude attempts to regulate their movement precisely because they embody the very mobility promised by economic reforms. [Vietnam, traffic, commodity, circulation, public space, mobility]
Defiant desire in Namibia: Female sexual–gender transgression and the making of political being
Authors: LORWAY ROBERT
Published: March 2008

In this article, I explore local productions of desire in Namibia by focusing on the engagement of young, working‐class lesbians with human rights ideologies of sexual freedom. I discuss how various techniques deployed by a sexual minority‐rights NGO allow youth to amplify and legitimize their embodied sense of sexual–gender difference. In my analysis of their self‐mediated incitement, I regard desire as a moral practice; practices of self‐determination and acts of resistance are generated and authenticated through repeated reflection on the internality of desire. My elaborations also emphasize class‐related issues. I argue that struggles with class and gender inequality destabilize the very notion of “sexual identity” in ways that open up political and erotic possibilities between lesbians and other working‐class women in Namibia, blurring the dividing lines of identity politics and of gender and class politics. [lesbian resistance, African sexuality, moral practice, desire, global queer identity, human rights]
“The Holocaust does not belong to European Jews alone”: The differential use of memory techniques in Israeli high schools
Authors: GOODMAN YEHUDA C. , MIZRACHI NISSIM
Published: March 2008

On the basis of participant‐observations of classroom discussions in Jewish Israeli high schools during two memorial days, we examine how different ethnoclass groups within a presumably consensual national collectivity remember the nation. We found that teachers use different memory techniques with different groups of students and in relation to different historical memories, and we suggest that doing so variously repositions subgroups toward the public sphere. We argue that, to understand ethnoclass memory work and its differential appropriation and refraction along ethnoclass divides, scholars need to go beyond the contents of historical narratives and collective ceremonies to inquire into the plethora of memory techniques social actors use. [ethnoclass, national memory, memory techniques, citizenship participation, hegemony, Israel, high school]
Standing in the shadows: Of matrilocality and the role of women in a village election in northern Thailand
Authors: BOWIE KATHERINE
Published: March 2008

In this article, I analyze a village election in Thailand to show how anthropological insights into kinship systems can provide important avenues into understanding the gender dynamics of electoral politics. Because few women hold public office in Thailand, Thai politics has been considered a male domain. Exploring four social dramas in which conflicts made the hidden role of women visible, I argue that the public domain of electoral politics in rural Thailand is embedded within village practices of matrilocality and matrilineal kinship. [politics, elections, public sphere, women, matrilocality, matrilineages, Thailand]
A house of one's own: Gender, migration, and residence in rural Mexico
Authors: PAULI JULIA
Published: March 2008

Gender dynamics in Mexican migrant communities have been conceptualized mainly in terms of transformations in conjugal relations. Other meaningful relations, especially conflict‐laden female in‐law relations, have not been discussed widely in the context of transnational communities. I show how this wider perspective on gender relations is essential for unraveling the social processes behind the boom in house construction that many rural regions in Mexico are experiencing. A growing number of women reduce the length of their often very traumatic residence in their mothers‐in‐law's houses or try to avoid it altogether by creatively appropriating new spaces—building houses—using migradólares, remittances from their husbands who work in the United States. The newly built houses both constitute and express changing gender and kin relations. In the long run, these changes are likely to erode the social security of members of the elderly population. [migration, gender, kinship, postmarital residence, domestic space, social security, Mexico]
Insulin‐Secretagogue Activity of p‐Methoxycinnamic Acid in Rats, Perfused Rat Pancreas and Pancreatic β‐Cell Line
Authors: Yibchok‐anun Sirintorn , Adisakwattana Sirichai , Moonsan Preecha , Hsu Walter H.
Published: March 2008

Abstract:  This study investigated the effect of p‐methoxycinnamic acid (p‐MCA) on plasma glucose and insulin concentrations in normal and streptozotocin‐induced diabetic rats. In both fasting and glucose‐loading conditions, an oral administration of p‐MCA (40–100 mg/kg) significantly decreased plasma glucose and also increased plasma insulin concentrations in both normal and diabetic rats. The onset of the p‐MCA‐induced antihyperglycaemia/hypoglycaemia was observed at 1 hr after administration. In perfused rat pancreas, p‐MCA (10–100 µM) stimulated insulin secretion about 1.4‐ and 3.1‐fold of basal–control group. In addition, p‐MCA (10 µM) enhanced glucose‐induced insulin secretion. Moreover, p‐MCA stimulated insulin secretion and increased intracellular Ca2+ concentration ([Ca2+]i) in insulinoma‐1 cells. Taken together, our findings suggested that p‐MCA exerted antihyperglycaemic/hypoglycaemic effect by stimulating insulin secretion from pancreas and could be developed into a new potential for therapeutic agent used in type 2 diabetic patients.
Antitumoural Effect of an l‐Amino Acid Oxidase Isolated from Bothrops jararaca Snake Venom
Authors: De Vieira Santos Mariana M. , Sant’Ana Carolina D. , Giglio José R. , Da Silva Reinaldo J. , Sampaio Suely V. , Soares Andreimar M. , Fecchio Denise
Published: March 2008

Abstract:  An l‐amino acid oxidase (BjarLAAO‐I) from Bothrops jararaca snake venom was highly purified using a stepwise sequential chromatography on Sephadex G‐75, Benzamidine Sepharose and Phenyl Sepharose. Purified BjarLAAO‐I showed a molecular weight around 60,000 under reducing conditions and about 125,000 in the native form, when analysed by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and gel filtration, respectively. BjarLAAO‐I is a homodimeric acidic glycoprotein, pI ~5.0, and N‐terminal sequence showing close structural homology with other snake venom LAAOs. The purified enzyme catalysed the oxidative deamination of l‐amino acids, the most specific substrate being l‐Phe. Five amino acids, l‐Ser, l‐Pro, l‐Gly, l‐Thr and l‐Cys were not oxidized, clearly indicating a significant specificity. BjarLAAO‐I significantly inhibited Ehrlich ascites tumour growth and induced an influx of polymorphonuclear cells, as well as spontaneous liberation of H2O2 from peritoneal macrophages. Later, BjarLAAO‐I induced mononuclear influx and peritoneal macrophage spreading. Animals treated with BjarLAAO‐I showed higher survival time.
Caffeine Inhibits the Proliferation of Liver Cancer Cells and Activates the MEK/ERK/EGFR Signalling Pathway
Authors: Okano Jun‐ichi , Nagahara Takakazu , Matsumoto Kazuya , Murawaki Yoshikazu
Published: March 2008

Abstract:  Caffeine has been reported to prevent hepatocarcinogenesis. We investigated the molecular mechanisms by which caffeine inhibits the growth of hepatocellular carcinoma (HCC) cells. We found that caffeine inhibited the proliferation of HCC cells via cell cycle arrest independent of apoptosis. We revealed a novel signalling axis for caffeine involving activation of the mitogen‐activated ERK‐regulating kinase (MEK)/extracellular signal‐regulated kinase (ERK) pathway that resulted in the downstream up‐regulation of epidermal growth factor receptor (EGFR), although the MEK/ERK/EGFR signalling pathway was not involved in the growth inhibitory effect of caffeine. Our data reveal that caffeine could be a promising candidate for the treatment of patients with HCC.
Inhibitory Effects on Cytochrome P450 Enzymes of Pentamidine and Its Amidoxime Pro‐Drug
Authors: Bürenheide Anja , Kunze Thomas , Clement Bernd
Published: March 2008

Abstract: Pentamidine is an antimicrobial drug, intravenously used in the treatment of trypanosomiasis, leishmaniasis or pneumocystis pneumonia. To elucidate potential drug interactions with pentamidine and N,N′‐dihydroxypentamidine, respectively, the cytochrome P450 (CYP450) inhibitory properties of these compounds were determined. The study was performedin vitroby using human liver microsomes and marker substrates of several CYP450 isoenzymes. Marker activities were investigated by high‐performance liquid chromatography in presence of known selective inhibitors or at different concentrations of pentamidine and N,N′‐dihydroxypentamidine, respectively. No or only minor influence on CYP1A2, 2A6, 2C9, 2C19, 2D6, 2E1 and 3A4 marker activities could be observed, suggesting that neither of the tested substances would exert a significant effect on hepatic CYP450 isoenzymes responsible for the metabolism of co‐administrated drugsin vivo. However,in vivostudies are needed before final conclusions can be drawn.
Identification of a Frequency Response Model of Joint Rotation
Authors: Becker J. D. , Mote C. D.
Published: March 2008

A second order, linear oscillator transfer function model is fit to the measured transfer function relating the abduction-adduction rotation of the first finger to the applied moment. Nearly constant isometric contractions of the first palmar and dorsal interossei are maintained by the subjects during the measurements. The stiffness and damping components of the identified models increase significantly with increasing isometric contraction when compared to those recorded under relaxed contraction. Muscle fatigue causes the natural frequency, damping ratio and stiffness of the joint rotation to decrease under full isometric contraction, and it causes the natural frequency and stiffness to increase when the muscles are relaxed.
Measurement of Changes in Ligament Tension with Knee Motion and Skeletal Maturation
Authors: Woo Savio L.-Y. , Weiss J. A. , Gomez M. A. , Hawkins D. A.
Published: March 2008

This study was designed to determine the in situ strains, stresses, and loads in the medial collateral ligament (MCL) of skeletally immature and mature rabbits. Using a noncontact method, the magnitudes of the in situ strains were first determined as a function of knee flexion angle. The MCL was divided into three anatomical regions (anterior, middle, and posterior) across its width. For strain measurements, the variation of a gauge length in these regions was obtained in the intact knee at 60, 90, and 120 deg of flexion. Subsequently, all soft tissues around the knee were dissected away, leaving the femur-MCL-tibia (FMT) complex. The MCL was allowed to retract freely and the new length, called the zero length, was measured. From this, the in situ strains were determined. To obtain the stress-strain relationship of the FMT complex, the specimens were subjected to tensile testing. Knowing the in situ strains and the stress-strain relationship, the in situ stresses in the three anatomical regions of the MCL were determined as a function of knee flexion angle. Multiplying these stresses by 1/3 of the cross-sectional area and summing the loads thus calculated, the in situ loads of the MCL were obtained. Our data suggest that the in situ load in the MCL is not large within the range of knee flexion angles studied, i.e., 1.4 to 2.7 N for the skeletally immature animals and 3.0 to 5.8 N for the skeletally mature animals. An increase in the in situ load with skeletal maturation was demonstrated.
Muscle Activation and Contraction: Constitutive Relations Based Directly on Cross-Bridge Kinetics
Authors: Zahalak George I. , Ma Shi-Ping
Published: March 2008

This paper reviews recent work aimed at deriving tractable constitutive relations for skeletal muscle from biophysical cross-bridge theories. Discussion is focused on a model proposed previously by the first author (the Distribution-Moment Model), which emphasizes the important role of the moments of the actin-myosin bond distribution function. The theory leads to a relatively simple third order state variable model for contraction dynamics in which the state variables are the three lowest order moments of the bond-distribution function; further, these three moments have simple macroscopic interpretations as muscle stiffness, force, and elastic energy. New results are presented on the formulation of a compatible model for excitation-contraction coupling, and this model requires the introduction of only one more state variable—the free calcium concentration.
Experimental Analysis of Pulsatile Flow Through Elastic Collapsible Tubes: Application to Cardiac Assist Device
Authors: Lichtenstein O. , Dinnar U.
Published: March 2008

This study presents a simulated analysis of Phased Compression Cardiac Assist Device (PCCAD) and evaluation of its applicability as a non-invasive temporary assist for a failing heart. The new technique is based on the chest pump mechanism for blood flow augmentation during external massage by phased compression of the abdominal and thoracic cavities. A semi-closed hydraulic system to simulate the systemic circulation was constructed; the system includes a left ventricle which functions according to the Starling principle and a pneumatic system which controls the pressures applied to the thoracic and abdominal cavities, in complete synchronization with the beating normal or failing heart. The possibility of manipulating the three pumps in series (venous, heart, and arterial) has been checked, and the principal parameters which effect the efficiency of the PCCAD were evaluated. This in-vitro analysis shows the high potential of a non-invasive temporary cardiac assist device. It points to the necessary measures one has to take in order to achieve good synchronization and to interfere externally with the augmentation of cardiac output or with the augmentation of root aortic pressure.
Secondary Flow Velocity Patterns in a Pulmonary Artery Model With Varying Degrees of Valvular Pulmonic Stenosis: Pulsatile In Vitro Studies
Authors: Sung Hsing-Wen , Yoganathan Ajit P.
Published: March 2008

The objective of this study was to characterize in detail the secondary flow velocity patterns in an in vitro model of a human (adult) pulmonary artery with varying degrees of valvular pulmonic stenosis. A two-dimensional laser Doppler anemometer (LDA) system was used to map the flow fields in the main (MPA), left (LPA), and right (RPA) branches of the pulmonary artery model. The study was conducted in the Georgia Tech right heart pulse duplicator system. A pair of counter-rotating secondary flows were observed in each daughter branch in which the fluid moved outwardly along the side walls and then circled back inwardly toward the center of the vessel. For the case of the “normal” valve, the two counter-rotating secondary flows were symmetric about the centerline. The strength of secondary flows in the RPA was much stronger than in the LPA. However, as the pulmonic valve became more stenotic, the two counter-rotating secondary flows in both the LPA and RPA were no longer symmetric. In addition, the strength of secondary flows in both daughter branches increased with increasing degree of valvular stenosis. The increment in the LPA was, however, greater than in the RPA. The study demonstrates the importance of analyzing complex biological flows from a three-dimensional viewpoint.
Model Studies of Nonsteady Flow Using Magnetic Resonance Imaging
Authors: Fei Ding-Yu , Kraft Kenneth A. , Fatouros Panos P.
Published: March 2008

A bolus-tracking magnetic resonance imaging (MRI) method has been employed to measure velocity profiles for oscillatory flow with and without a steady flow component as well as pulsatile flow in an axisymmetric tube model. A range of flow conditions within normal physiological limits was tested. The imaged velocity profiles were observed to be generally in accord with theoretical predictions. Instantaneous flow rates calculated from the MR images agreed well with those assessed using an ultrasonic flowmeter. Because MRI is noninvasive and poses few risks to subjects, this technique is potentially useful for studying vascular hemodynamics in vivo.
Effects of Data Smoothing on the Reconstruction of Helical Axis Parameters in Human Joint Kinematics
Authors: de Lange A. , Huiskes R. , Kauer J. M. G.
Published: March 2008

In biomechanical joint-motion analyses, the continuous motion to be studied is often approximated by a sequence of finite displacements, and the Finite Helical Axis (FHA) or “screw axis” for each displacement is estimated from position measurements on a number of anatomical or artificial landmarks. When FHA parameters are directly determined from raw (noisy) displacement data, both the position and the direction of the FHA are ill-determined, in particular when the sequential displacement steps are small. This implies, that under certain conditions, the continuous pathways of joint motions cannot be adequately described. The purpose of the present experimental study is to investigate the applicability of smoothing (or filtering) techniques, in those cases where FHA parameters are ill-determined. Two different quintic-spline smoothing methods were used to analyze the motion data obtained with Roentgenstereophotogrammetry in two experiments. One concerning carpal motions in a wrist-joint specimen, and one relative to a kinematic laboratory model, in which the axis positions are a priori known. The smoothed and nonsmoothed FHA parameter errors were compared. The influences of the number of samples and the size of the sampling interval (displacement step) were investigated, as were the effects of equidistant and nonequidistant sampling conditions and noise invariance.
Two-Dimensional Stress-Strain Relationship for Canine Pericardium
Authors: Choi Hwa Soon , Vito R. P.
Published: March 2008

Two-dimensional pseudoelastic mechanical properties of the canine pericardium were investigated in vitro. The pericardium was assumed to be orthotropic. The material symmetry axis was determined a priori and aligned with the stretching axis. Various biaxial stretching tests were then performed and a set of data covering a wide range of strains was constructed. This complete data set was fitted to a new exponential type constitutive model, and a set of true material constants was determined for each specimen. Using the constitutive model and the true material constants, the results from constant lateral force tests and constant lateral displacement tests were predicted and compared with experiment.
Surface Tension and the Dodecahedron Model for Lung Elasticity
Authors: Kimmel E. , Budiansky B.
Published: March 2008

Macroscopic elastic moduli governing the incremental deformations of lung parenchyma are calculated on the basis of a model for an individual lung element in the shape of a regular dodecahedron. Elastic stiffness within the element is provided by pin-jointed tension members along the edges of the dodecahedron, surface tension is incorporated into its pentagonal faces, and the influence of transpulmonary pressure is simulated by an externally applied hydrostatic tension. The analysis is based on a variational statement of nonlinear structural mechanics, and the results show how the moduli depend on the effective inflation pressure, the constitutive behavior of the idealized truss members, and the surface-area dependent surface tension. The theory is discussed in the light of available experimental information. A more general analysis is needed to account for the effects of structural as well as surface-tension hysteresis.
Gas Absorption in Pulmonary Airways at Low Peclet Number
Authors: Grotberg J. B.
Published: March 2008

A mathematical model is presented that investigates the mass transport of a diffusible and soluble gas contaminant through a liquid-lined tube when the Peclet number is small. The transport is determined by four dimensionless parameters: λ, the tube aspect ratio; d, the relative difference in end concentrations; Γ, the radial transport coefficient; and Pe, the Peclet number. The problem is formulated for arbitrary Γ, but in the case of ozone and nitrous oxides the value of Γ is small. An asymptotic analysis for Pe ≪ 1 and Γ ≪ 1 is presented which yields the concentration field and transport characteristics we seek. It also provides a low Peclet number analysis for the conjugate problem of mass and heat transfer that is not currently available in the literature. The application to transport in the small airways of the lung is discussed, particularly the radial absorption differences in inspiratory and expiratory flow. Depending on the relative sizes of Γ and Pe, fractional uptake decreases with increasing Pe during inspiration but can increase during expiration.
Cell Biomechanics: A Brief Overview
Authors: Hochmuth Robert M.
Published: March 2008

In this issue of the JOURNAL OF BIOMECHANICAL ENGINEERING, there are eleven papers and one technical brief in the general area of “Cell Biomechanics.” In general, the work in these papers focuses on measuring and characterizing the mechanical and adhesive properties of cells and membranes. Included are studies of lipid membranes, erythrocytes, endothelial cells, and neutrophils. Characterizing and measuring the properties and behavior of cells in both passive and active states present a major challenge to investigators in this field. In this paper in the comments to follow, a simple overview of the field is presented and the principles and techniques used in the studies of cell biomechanics are discussed.
Determination of the Red Blood Cell Apparent Membrane Elastic Modulus From Viscometric Measurements
Authors: Drochon A. , Barthes-Biesel D. , Lacombe C. , Lelievre J. C.
Published: March 2008

Rhelogical measurements on a dilute suspension of red blood cells (RBCs) are interpreted by means of a microheological model that relates the shear evolution of the apparent viscosity to the intrinsic properties of the suspended particles. It is then possible to quantify the average deformability of a RBC population in terms of a mean value of the membrane shear elastic modulus, Es. Dilute suspensions of erthrocytes exhibit a shear-thinning behavior with a constant high shear viscosity. This behavior is identical to the one predicted for a suspension of spherical capsules where the same phenomena of deformation and orientation prevail. A comparison between theoretical and experimental curves yields a mean value of Es, assuming all other cell properties—internal viscosity, geometry—to be otherwise equal. In Dextran, the values of Es for normal RBCs are found to be of order 3.10−6 N/m. For erythrocytes hardened by heat exposure for 15 minutes at 48°C, the increase in Es reaches 45 percent. This procedure of shear elastic modulus determination is easy to perform and seems to give a good discrimination between normal and altered erythrocytes.
Effects of Cell Lysis on the Rheological Behavior of Red Blood Cell Suspensions
Authors: Tran-Son-Tay Roger , Beaty B. B. , Coffey B. E.
Published: March 2008

Rheological studies of lysed cell suspensions are performed with a magneto acoustic ball microrheometer. Two methods for lysing the cells are developed in order to provide cell volume concentrations identical to control intact cell suspensions. The first uses a freeze-thaw technique and the second uses sonication. It is found that cell suspensions disrupted by sonication have a lower viscosity than intact suspensions, whereas cell suspensions lysed by the freeze-thaw method exhibit a higher viscosity. Sonication is discovered to have a detrimental impact on the cell membrane, and to cause complete destruction of the cell membrane structure. Measurements of the steady state viscosity show that indeed the presence of the membrane is not detected, and that what is measured is mainly the viscosity of the hemoglobin solution. On the other hand, freeze-thaw results indicate that at least two phenomena occur. The first phenomemon, occurring during the first freeze-thaw cycle, produces an increase in viscosity and in viscoelasticity. The second one, taking place after subsequent freeze-thaw cycles, induces a decrease in the bulk rheological properties. Several possible mechanisms are presented to explain the observed phenomena.
Determination of Cellular Mechanical Properties by Cell Poking, With an Application to Leukocytes
Authors: Zahalak G. I. , McConnaughey W. B. , Elson E. L.
Published: March 2008

In this paper we review the cell-poking technique as an approach for investigating the mechanical properties of living cells. We first summarize the rationale for the technique and the mainly qualitative results obtained so far. Then we provide a technical description of the instrument as it is configured at present. This is followed by a discussion of the current status of analytical results available for interpreting cell-poking measurements. In the final section we apply these results to an analysis of unmodulated and modulated lymphocytes and neutrophils, and conclude that the mechanical response of these leukocytes to indentation is not consistent with simple models developed by previous investigators on the basis of micropipette-aspiration experiments.
Kinematics of Cytoplasmic Deformation in Neutrophils During Active Motion
Authors: Simon S. I. , Schmid-Scho¨nbein G. W.
Published: March 2008

A procedure is proposed to measure the cytoplasmic deformation in active motile neutrophils in the form of cytoplasmic strains and strain rates. Three neighboring microspheres in a local region of the cytoplasm serve as markers for local motion. Their positions are tracked by means of a high resolution light microscope and serve to compute nonlinear measures of strains and strain rates together with the principal strains and principal directions. Active neutrophils exhibit large cytoplasmic strains both during periodic pseudopod projections and during continuous locomotion in a polarized shape. The cytoplasmic motion is often synchronized with the whole cell deformation. The local cytoplasmic strains exceed the strains estimated for the whole cell and are not reversible except in some cases of single pseudopod projections. Large strains are observed both in attached and freely suspended cells. Strain rates are relatively constant but show an increase during the pseudopod retraction phase. Local cytoplasmic strains in neutrophils are inhomogeneous and reach large values during passage of the contraction rings. Neutrophils rendered passive by treatment with cytochalasin or EDTA show a random motion of microspheres with much smaller displacements. These observations suggest that the cytoplasm of active neutrophil exhibits large cytoplasmic strains and strain rates in the absence of an external stress resulting in a high degree of intracellular mixing. The proposed technique may be applied to a wide range of problems in cell biology.
Cell-Cell, Cell-Substrate Adhesion: Theoretical and Experimental Considerations
Authors: Tozeren A.
Published: March 2008

Cell-cell adhesion plays a fundamental role in tissue and organ development, cell mediated immunity and blood flow. In the present study a micro-mechanical model of specific adhesion is presented. Analytical expressions are derived for the adhesive energy density (Γ) at zero speed of peeling for the cases of immobile (trapped) as well as laterally mobile bonds. It is shown that Γ increases in both cases with the increasing density of bonds and with the binding of affinity of unstressed bonds. In the case of laterally mobile bonds Γ also increases with the extent of peeling. The analytical results are shown to be valid whether or not one takes into account of the bending stiffness of adhering membranes. It is also shown that Γ does not depend on the functional form of bond elasticity. The effect of the speed of peeling on the number density distribution of attached bonds is considered next. Numerical solutions for the energy required to separate conjugated cell pairs are presented. The theoretical predictions are then used to analyze experimental data on red cell aggregation and adhesion between a cytotoxic-T cell and its target cell. The results show that the binding affinity of unstressed bonds and their number density before conjugation can be obtained from data on slow peeling of cell-pairs. The information on the diffusivity of bonds, their stiffness and their rates of attachment and detachment are more difficult to obtain, requiring a set of experiments with increasing rates of separation (conjugation) of cell-pairs.