bluuebunny/crossref_metadata_2025 huggingface dataset:
Determinants of Sexual Function among Women with Type 2 Diabetes in a Nigerian Population
Authors: Olarinoye John , Olarinoye Adebunmi
Published: March 2008

Introduction

Sexual health is an important but often neglected component of diabetes care. Unlike erectile dysfunction, female sexual dysfunction has not been well studied among Nigerian diabetics.

Aims

To assess the sexual function of women with diabetes, and to determine its clinical correlates.

Methods

The sexual performances of 51 women with type 2 diabetes mellitus attending the Diabetes Clinic, University of Ilorin Teaching Hospital were assessed using the Female Sexual Function Index (FSFI) questionnaire. The Female Sexual Function (FSF) scores in each domain of sexual function were then compared with those of 39 nondiabetic controls. The associations between the FSF scores and certain clinical variables, as well as some diabetic complications, were also determined.

Main Outcome Measures

Sexual performance of the women as measured by the FSF scores using the FSFI questionnaires.

Results

The FSF score in the diabetic women was 20.5 (±8.3) compared with a score of 31.2 (±8.8) in the control (P value=0.00). The FSF scores in the arousal, pain, orgasm, and overall satisfaction domains were all lower in the diabetic women (P value<0.05). There was no significant difference in the scores for “desire” domain in the two groups (P value > 0.05). Women with diabetes attempted sex less frequently (P <0.05). There was a negative correlation between the ages of the women and all the domains of sexual function (P value<0.05). Duration of diabetes correlated negatively with comfort (P value=0.04), lubrication (P =0.03), frequency (P value=0.05), as well as orgasm (P value=0.04) domains. There was no significant relationship between the FSF score and body mass index, blood pressure, and glycemic control. There was no significant difference between the FSF scores of diabetic women with complications and those without (P value > 0.05).

Conclusions

Diabetes significantly impairs the sexual performance of the Nigerian women afflicted with the disease. Determinants of FSF include age, duration of diabetes illness, and presence of menopause.
Male Erectile Dysfunction and Cardiovascular Disease: Is There an Intimate Nexus?
Authors: Chew Kew-Kim , Bremner Alexandra , Jamrozik Konrad , Earle Carolyn , Stuckey Bronwyn
Published: March 2008

Introduction

Various studies report increased risk of erectile dysfunction (ED) in men with cardiovascular (CV) disease and postulate an intimate nexus between the two conditions.

Aim

To examine the association of ED with CV risk factors and disease in a population-based cross-sectional observational study conducted in Western Australia (WA).

Method

Postal questionnaires were sent to randomly selected age-stratified male population samples obtained from the WA Electoral Roll.

Main Outcome Measures

In addition to items covering sociodemographic and self-reported clinical information, the 5-item International Index of Erectile Function (IIEF-5) was used.

Results

Of the 1,580 participants, the ages of 1,514 were known and ranged from 20 to 99 years (mean 57.9, median 59.1, standard deviation 18.5). CV risk factors and disease were more prevalent with increasing age and among participants with ED and severe ED. The age-adjusted odds of ED were significantly higher among participants with hypertension (odds ratio [OR] 1.47; 95% confidence intervals [CI] 1.05, 2.07), ischemic heart disease (OR 1.80; 95% CI 1.10, 2.94), and stroke (OR 3.30; 95% CI 1.22, 8.88), and with these conditions and peripheral arterial disease grouped together as CV disease (OR 1.85; 95% CI 1.34, 2.56). Many participants with hyperlipidemia were receiving treatment, and the age-adjusted odds for ED were not significantly higher. The age-adjusted odds of ED among participants with diabetes mellitus were 2.76 (95% CI 1.52, 5.00), and were 3.21 (95% CI 1.03, 10.05) when hypertension and hyperlipidemia were also present.

Conclusions

The findings support the postulated intimate nexus between ED and CV disease. The adverse effects of age and CV risk factors and disease on erectile function compound each other. The socioeconomic, epidemiologic, and clinical implications are immense.
Subarachnoid Hemorrhage as Complication of Phenylephrine Injection for the Treatment of Ischemic Priapism in a Sickle Cell Disease Patient
Authors: Davila Hugo H. , Parker Justin , Webster J. Christopher , Lockhart Jorge L. , Carrion Rafael E.
Published: March 2008

Introduction

Ischemic priapism (IP) is a urologic condition, which necessitates prompt management. Intracavernosal injection of phenylephrine is a usual treatment modality utilized for the management of these patients.

Aim

We present a case of subarachnoid hemorrhage following intracavernosal injection of phenylephrine for IP in a patient with sickle cell disease.

Methods

We analyzed the degree of subarachnoid hemorrhage in our patient after intracavernosal injection of phenylephrine. The patient had an acute rise in blood pressure during corporal irrigation. This was followed by the onset of severe headache. Computed tomography (CT) scan confirmed the diagnosis of a subarachnoid hemorrhage.

Main Outcome Measure

Subarachnoid hemorrhage associated with intracavernosal injection of phenylephrine.

Result

A 23-year-old African American male with a history of sickle cell disease presented with a painful penile erection. The patient was started on intravenous fluids, oxygen by nasal canula, and analgesic medication. After this, a blood gas was obtained from his left corpora cavernosa. This was followed by normal saline irrigation and injection of phenylephrine. The patient complained of a sudden, severe “terrible headache” immediately following the last injection, and noncontrast CT scan of the head was obtained and a subarachnoid hemorrhage was noted. The patient was admitted for observation and no significant changes were noted.

Conclusions

Intracavernosal injection of phenylephrine for the management of IP can be associated with several possible complications. We present our single case complicated with the formation of a subarachnoid hemorrhage. The patient was treated conservatively and had no long-term neurologic sequelae.
Effect of Testosterone on Potassium Channel Opening in Human Corporal Smooth Muscle Cells
Authors: Han Deok Hyun , Chae Mee Ree , Jung Jae Hun , So Insuk , Park Jong Kwan , Lee Sung Won
Published: March 2008

Introduction

In humans, the role of testosterone in sexual functions, including sexual desire, nocturnal penile erections, and ejaculatory volume, has been relatively well established. However, the effects of testosterone on intrapenile structure in humans remains controversial.

Aim

We assessed the direct effects of testosterone on potassium channels in human corporal smooth muscle cells, in an effort to understand the mechanisms inherent to the testosterone-induced relaxation of corporal smooth muscle cells at the cellular and molecular levels.

Methods

We conducted electrophysiologic studies using cultured human corporal smooth muscle cells. We evaluated the effects of testosterone on potassium channels—BKCa and KATP channels—by determining the whole-cell currents and single-channel activities. For the electrophysiologic recordings, whole-cell and cell-attached configuration patch-clamp techniques were utilized.

Main Outcome Measures

Changes in whole-cell currents and channel activities of BKCa and KATP channels by testosterone.

Results

Testosterone (200 nM) significantly increased the single-channel activity of calcium-activated potassium (BKCa) channels and whole-cell K+ currents by 443.4 ± 83.4% (at +60 mV; N=11, P <0.05), and this effect was abolished by tetraethylammonium (TEA) (1 mM), a BKCa channel blocker. The whole-cell inward K+ currents of the KATP channels were also increased by 226.5 ± 49.3% (at –100 mV; N=7, P <0.05). In the presence of a combination of vardenafil (10 nM) and testosterone (200 nM), the BKCa channel was activated to a significantly higher degree than was induced by testosterone alone.

Conclusions

The results of patch-clamp studies provided direct molecular evidence that testosterone stimulates the activity of BKCa channels and KATP channels. An understanding of the signaling mechanisms that couple testosterone receptor activation to potassium channel stimulation will provide us with an insight into the cellular processes underlying the vasorelaxant effects of testosterone.
The Effect of Comorbidity and Socioeconomic Status on Sexual and Urinary Function and on General Health-Related Quality of Life in Men Treated with Radical Prostatectomy for Localized Prostate Cancer
Authors: Karakiewicz Pierre I. , Bhojani Naeem , Neugut Alfred , Shariat Shahrokh F. , Jeldres Claudio , Graefen Markus , Perrotte Paul , Peloquin Francois , Kattan Michael W.
Published: March 2008

Introduction

Different treatments for localized prostate cancer (PCa) may be associated with similar overall survival but may demonstrate important differences in health-related quality of life (HRQOL). Therefore, valid interpretation of cancer control outcomes requires adjustment for HRQOL.

Aim

To assess the effect of comorbidity and socioeconomic status (SES) on sexual and urinary function as well as general HRQOL in men treated with radical prostatectomy (RP) for PCa.

Methods

We sent a self-addressed mail survey, composed of the research and development short form 36-item health survey, the PCa-specific University of California at Los Angeles (UCLA) Prostate Cancer Index (PCI), as well as a battery of items addressing SES and lifetime prevalence of comorbidity, to 4,546 men treated with RP in Quebec between 1988 and 1996.

Main Outcome Measures

The association between comorbidity, SES, and HRQOL was tested and quantified using univariable and multivariable linear regression models.

Results

Survey responses from 2,415 participants demonstrated that comorbidity and SES are strongly related to sexual, urinary, and general HRQOL in univariable and multivariable analyses. In multivariable models, the presence of comorbid conditions was associated with significantly worse HRQOL, as evidenced by lower scale scores by as much as 17/100 points in general domains, and by as much as 10/100 points in PCa-specific domains. Favorable SES characteristics were related to higher general (up to 9/100 points) and higher PCa-specific (up to 8/100 points) HRQOL scale scores.

Conclusions

Comorbidity and SES are strongly associated with sexual, urinary and general HRQOL.
The Roles of Testosterone and Alpha-Amylase in Exercise-Induced Sexual Arousal in Women
Authors: Hamilton Lisa Dawn , Fogle Emily A. , Meston Cindy M.
Published: March 2008

Introduction

Several studies have demonstrated that moderate exercise increases genital response to erotic stimuli in women. The increase in genital arousal could be the result of various changes that can occur in response to exercise including changes in hormone levels, neurotransmitter levels, mood, and autonomic nervous system activity.

Aim

The present study was an attempt to shed light on two such mechanisms through which exercise enhances sexual arousal.

Method

Sixteen participants came into the lab on two separate occasions: during one visit, they filled out questionnaires for 20 minutes, and during the other visit, they exercised on a treadmill for 20 minutes. The questionnaires and exercise were both followed by the presentation of a neutral then erotic film during which the women's physiological sexual arousal was measured. Saliva samples were taken at baseline, prefilm, and postfilm.

Main Outcome Measures

Subjective arousal was measured using a self-report questionnaire, and genital arousal was measured by a vaginal photoplethysmograph. Testosterone and α-amylase (a marker of sympathetic nervous system [SNS] activity) were measured via saliva assays.

Results

Findings replicated previous studies showing a significant increase in physiological sexual arousal with exercise. There was a significant increase in α-amylase across the study in the exercise condition, but not in the no-exercise condition. There were no differences in testosterone levels between the exercise and no-exercise conditions.

Conclusions

SNS activity is one mechanism through which exercise increases genital sexual arousal. Testosterone does not mediate the relationship between exercise and genital sexual arousal.
Does Erectile Tissue Angioarchitecture Modify with Aging? An Immunohistological and Morphometric Approach
Authors: Costa Carla , Vendeira Pedro
Published: March 2008

Introduction

Erectile dysfunction is a common problem in aged men; however, which vascular cavernosal alterations occur with age progression remain unclarified.

Aim

Using cavernosal tissue from rats of various ages, we aimed to thoroughly assess erectile vascular-associated morphologic, immunohistological, and morphometric alterations during aging.

Methods

Male Wistar rats were divided according to age in groups of 2, 6, 12, 18, 24 months old (N=5). Cavernosal tissue of all groups was collected and processed for morphologic evaluation, immunodetection of α-smooth muscle actin and von Willebrand factor and morphometric quantification of vascular and smooth muscle cell (SMC) areas.

Main Outcome Measures

The morphometric assessment of age-related alterations in cavernosal vascular and SMCs using the ImageJ image-processing program.

Results

Morphologic and immunohistological evaluation showed a similar structure of erectile tissue among all age groups, divided in two cavernosal bodies containing numerous sinusoidal vascular spaces surrounded by SMCs. Additionally, we observed a reduction of SMC content and an increase in the caliber of vascular spaces, with aging. This was confirmed by the morphometric quantification of the vascular and SMC areas (mean area ×103 µm2 ± ×103 standard error). Two-month-old animals had a mean vascular area of 4.21 ± 0.51, approximately 3.5-fold less than the 6-month-old group. The differences increased when comparing the youngest groups with the 12-, 18-, and 24-month-old animals, with mean measurements of 18.99 ± 1.91, 25.23 ± 2.76, and 26.34 ± 2.97. Conversely, SMC areas progressively decreased between 2- and 6-month-old animals, from 6.75 ± 0.90 to 6.38 ± 1.24. The elderly 12-, 18-, and 24-month-old groups presented an approximated 1.5-fold reduction on SMCs area, showed by the respective measurements of 4.11 ± 0.50, 4.01 ± 0.35, and 4.02 ± 0.44.

Conclusions

We demonstrated that cavernosal angioarchitecture was modified with aging. The decrease in SMCs and the considerable enlargement of vascular lumens may limit the basic function of penile vascular tree in the elderly.
Menstrual Cycle-Related Changes in Circulating Androgens in Healthy Women With Self-Reported Normal Sexual Function
Authors: Salonia Andrea , Pontillo Marina , Nappi Rossella E. , Zanni Giuseppe , Fabbri Fabio , Scavini Marina , Daverio Rita , Gallina Andrea , Rigatti Patrizio , Bosi Emanuele , Bonini Pier Angelo , Montorsi Francesco
Published: March 2008

Introduction

There is currently neither a clinically useful, reliable and inexpensive assay to measure circulating levels of free testosterone (T) in the range observed in women, nor is there agreement on the serum free T threshold defining hypoandrogenism that is associated with female-impaired sexual function.

Aim

Following the Clinical and Laboratory Standards Institute guidelines, we generated clinically applicable ranges for circulating androgens during specific phases of the menstrual cycle in a convenience sample of 120 reproductive-aged, regularly cycling healthy European Caucasian women with self-reported normal sexual function.

Methods

All participants were asked to complete a semistructured interview and fill out a set of validated questionnaires, including the Female Sexual Function Index, the Female Sexual Distress Scale, and the 21-item Beck's Inventory for Depression. Between 8 am and 10 am, a venous blood sample was drawn from each participant during the midfollicular (day 5 to 8), the ovulatory (day 13 to 15), and the midluteal phase (day 19 to 22) of the same menstrual cycle.

Main Outcome Measures

Serum levels of total and free testosterone, Δ4-androstenedione, dehydroepiandrosterone sulphate and sex hormone-binding globulin during the midfollicular, ovulatory and midluteal phase of the same menstrual cycle.

Results

Total and free T levels showed significant fluctuations, peaking during the ovulatory phase. No significant variation during the menstrual cycle were observed for Δ4-androstenedione and dehydroepiandrosterone sulphate. Despite the careful selection of participants that yielded an homogeneous group of women without sexual disorders, we observed a wide range of distribution for each of the circulating androgens measured in this study.

Conclusions

This report provides clinically applicable ranges for androgens throughout the menstrual cycle in reproductive-aged, regularly cycling, young healthy Caucasian European women with self-reported normal sexual function.
Penile Traction Therapy for Treatment of Peyronie's Disease: A Single-Center Pilot Study
Authors: Levine Laurence A. , Newell Mark , Taylor Frederick L.
Published: March 2008

Introduction

Peyronie's disease (PD) is a fibrotic disorder of the penis whose etiopathophysiology remains unclear. At this time, there is no known reliable nonsurgical treatment. This study reviews our experience with external penile traction therapy to correct the deformity associated with this disorder.

Aim

To evaluate prolonged external penile traction as a nonsurgical treatment for PD.

Methods

Ten men with PD completed this noncontrolled pilot study of traction therapy using the FastSize Penile Extender. Nearly all (90%) had failed prior medical therapy. Traction was applied as the only treatment for 2–8 hours/day for 6 months. All subjects underwent pre- and post-treatment physical examination including measurement of stretched flaccid penile length (SPL) and biothesiometry.

Main Outcome Measures

Curvature and girth were measured during erection before and after treatment with dynamic duplex ultrasound. Assessment of erectile and sexual function was further assessed with the International Index of Erectile Function and Quality of Life Specific to Male Erection Difficulties (QOL-MED) questionnaires. At 3 and 6 months post-treatment, SPL was measured and subjective assessment of deformity by the patient was recorded.

Results

Subjectively all men noted reduced curvature estimated at 10–40 degrees, increased penile length (1–2.5 cm) and enhanced girth in areas of indentation or narrowing. Objective measures demonstrated reduced curvature in all men from 10–45 degrees; average reduction for the group was 33% (51–34 degrees). SPL increased 0.5–2.0 cm and erect girth increased 0.5–1.0 cm with correction of hinge effect in four out of four men. International Index of Erectile Function-erectile function domain increased from 18.3–23.6 for the group. Changes in quality of life by QOL-MED were not found to be statistically significant in this small series. There were no adverse events including skin changes, ulcerations, hypoesthesia or diminished rigidity.

Conclusion

Prolonged daily external penile traction therapy is a new approach for the nonsurgical treatment of PD. Further study appears warranted given the response noted in this pilot study.
SYNTHESIS OF DOUBLY AND MULTIPLY ISOTOPICALLY LABELED RETINALS
Authors: Groesbeek M. , Lugtenburg J.
Published: March 2008

Abstract— In this paper a consecutive synthetic scheme is described that allows the synthesis of multiply 13C labeled retinals with labels in the conjugated chain. This scheme can be extended to incorporation of 2H labels in the conjugated chain. Also carotenoids can be multiply 13C labeled with this strategy. The same approach has been used to label amino acids.
CONFORMATIONAL ANALYSIS OF THE RHODOPSIN CHROMOPHORE USING BICYCLIC RETINAL ANALOGUES
Authors: Ito Masayoshi , Katsuta Yuko , Imamoto Yasushi , Shichida Yoshinori , Yoshizawa Tôru
Published: March 2008

Abstract— For investigation of the chromophore conformation around the trimethyl cyclohexene ring and of the origin of the induced β‐circular dichroism band in rhodopsin, two C6‐C7 single bond‐fixed retinal analogues, 6s‐cb‐ and 6s‐trans‐locked bicyclic retinals (6 and 7, respectively) were synthesized and incorporated into bovine opsin in CHAPS‐PC mixture. 6s‐cb‐ and 6s‐tram‐Locked rhodopsin analogues (8 and 9) with A max at 539 and 545 nm, respectively, were formed. Interestingly, both 8 and 9 displayed α‐ and β‐circular dichroism bands. The ellipticity of α‐bands are similar in each other, while the β‐band of 8 was about three times stronger than that of 9. Irradiation of 6s‐trans‐locked rhodopsin, 9, in the presence of hyroxylamine, resulted in the formation of only one of the enantiomers of 6s‐rrans‐locked retinal oxime showing a positive circular dichroism signal at around 390 nm. This fact strongly suggests that the retinal binding site of rhodopsin shows a chiral discrimination. From these experimental results, the interactions between the trimethyl cyclohexene ring portion in the chromophore and the neighbouring protein moiety in the rhodopsin molecule are discussed.
CONFORMATIONAL ENERGETICS AND EXCITED STATE LEVEL ORDERING IN 11‐cis RETINAL*
Authors: Tallent Jack R. , Birge Jonathan R. , Zhang Chian‐Fan , Wenderholm Elaine , Birge Robert R.
Published: March 2008

Abstract— Semiempirical molecular orbital theory and semiclassical solvent effect theory are used to analyze the conformational and electronic properties of the 12‐s‐cis and 12‐s‐trans conformers of 11‐cis retinal. The goal is to examine the influence of solvent environment on the equilibrium geometries of these conformers as well as to provide a perspective on the electronic transitions that contribute to the four band systems that are observed in the 200–500 nm region of the optical spectrum. We conclude that the 12‐s‐cis isomer is more stable in vacuum, but that the 12‐s‐trans conformer is preferentially stabilized in both polar and nonpolar solvent environment due to dispersive as well as electrostatic interactions. This observation is in substantial agreement with previous literature results. In contrast, our analysis of the excited state manifold indicates that the spectral features observed in the absorption spectrum are asSociated with a complex set of overlapping transitions. A total of 18 π←π transitions contribute to the four bands, and in some cases, conformation changes the relative contribution of the individual transitions that define the overall band shape. This study provides the first definitive assignments for all four band systems.
EXCITED STATE DYNAMICS OF RETINAL PROTEINS AS STUDIED BY FOURIER TRANSFORM OF OPTICAL ABSORPTION SPECTRUM—I. DEVELOPMENT OF ANALYTICAL METHOD
Authors: Kakitani Toshiaki , Hatano Yasuyo , Shichida Yoshinori , Imamoto Yasushi , Tokunaga Fumio , Kakitani Hiroko
Published: March 2008

Abstract— We significantly improved the analytical method for the study of excited state dynamics of pigments, by means of the time correlation function (tcf) of the vibrational wavepacket which is produced by the Fourier transform of experimentally obtained optical absorption spectra (FTOA). Applying the tcf method to the spectra of rhodopsin at 0°C and ‐180°C, we observed specific peaks which are slightly different between 0°C and ‐180°C in the early time region (1–130 fs) of the absolute value of tcf, representing a characteristic propagation of the wavepacket along a reaction coordinate pertinent to the cis‐trans photoisomerization of the chromophore accompanying the motion of protein moiety. From the analysis of phase angle propagation, we obtained a rather small relaxation energy, 6–7 kcal/mol. Based on these results, we can say that FTOA analysis is useful as one of the most powerful techniques for the study of very early procedures in the excited state dynamics of pigments.
EXCITED STATE DYNAMICS OF RETINAL PROTEINS AS STUDIED BY FOURIER TRANSFORM OF OPTICAL ABSORPTION SPECTRUM—II. THEORETICAL ANALYSIS OF WAVEPACKET PROPAGATION OF RHODOPSIN
Authors: Kakitani Toshiaki , Matsuda Narifumi , Hatano Yasuyo , Shichida Yoshinori , Kakitani Hiroko
Published: March 2008

Abstract— We theoretically calculated the absolute value of the time correlation function (tcf) of the wavepacket propagation in the excited state using the independent harmonic oscillators model for vibration and compared it with the experimental data obtained by the Fourier transform of optical absorption spectrum (FTOA) of rhodopsin in the preceding paper. We found that the theoretically calculated tcf differs significantly from the FTOA data. This fact indicates that the intrinsic harmonic oscillators model is too crude. We showed that better agreement is obtained between the calculated tcf and the FTOA data if we add an extra mode with low frequency and considerable decay constant which is not observable in the resonance Raman spectra. We also proposed that substantial mode‐mixing would take place among normal coordinates of vibrations at the Franck‐Condon state of the excited state and would contribute to the very rapid relaxation of vibrational energies.
IDENTIFICATION OF THE PROTON ACCEPTOR OF SCHIFF BASE DEPROTONATION IN BACTERIORHODOPSIN: A FOURIER‐TRANSFORM‐INFRARED STUDY OF THE MUTANT ASP85 → GLU IN ITS NATURAL LIPID ENVIRONMENT
Authors: Fahmy Karim , Weidlich Olaf , Engelhard Martin , Tittor Jörg , Oesterhelt Dieter , Siebert Friedrich
Published: March 2008

Abstract— In order to assign the proton acceptor for Schiff base deprotonation in bacteriorhodopsin to a specific Asp residue, the photoreaction of the Asp85 → Glu mutant, as expressed in Halobacterium sp. GRB, was investigated by static low‐temperature and time‐resolved infrared difference spec‐troscopy. Measurements were also performed on the mutant protein labeled with [4‐13C]Asp which allowed discrimination between Asp and Glu residues. 14,15‐di13C‐retinal was incorporated to distinguish amide‐II absorbance changes from changes of the ethylenic mode of the chromophore. In agreement with earlier UV‐VIS measurements, our data show that from both the 540 and 610 nm species present in a pH‐dependent equilibrium, intermediates similar to K and L can be formed. The 14 ms time‐resolved spectrum of the 540 nm species shows that a glutamic acid becomes protonated in the M‐like intermediate, whereas the comparable difference spectrum of the 610 nm species demonstrates that in the initial state a glutamic acid is already protonated. In conjunction with earlier observations of protonation of an Asp residue in wild‐type M, the data provide direct evidence that the proton acceptor in the deprotonation reaction of the Schiff base is Asp85.
TIME‐RESOLVED FOURIER TRANSFORM INFRARED SPECTROSCOPY OF THE BACTERIORHODOPSIN MUTANT TYR‐185→E: ASP‐96 REPROTONATES DURING O FORMATION; ASP‐85 AND ASP‐212 DEPROTONATE DURING O DECAY
Authors: Bousché Olaf , Sonar Sanjay , Krebs Mark P. , Khorana H. Gobind , Rothschild Kenneth J.
Published: March 2008

Abstract— The protonation state of key aspartic acid residues in the O intermediate of bacteriorhodopsin (bR) has been investigated by time‐resolved Fourier transform infrared (FTIR) difference spectroscopy and site‐directed mutagenesis. In an earlier study (Bouschéet al., J. Biol Chem. 266, 11063–11067, 1991) we found that Asp‐96 undergoes a deprotonation during the M→N transition, confirming its role as a proton donor in the reprotonation pathway leading from the cytoplasm to the Schiff base. In addition, both Asp‐85 and Asp‐212, which protonate upon formation of the M intermediate, remain protonated in the N intermediate. In this study, we have utilized the mutant Tyr‐185→Phe (Y185F), which at high pH and salt concentrations exhibits a photocycle similar to wild type bR but has a much slower decay of the O intermediate. Y185F was expressed in native Halobacterium halobium and isolated as intact purple membrane fragments. Time‐resolved FTIR difference spectra and visible difference spectra of this mutant were measured from hydrated multilayer films. A normal N intermediate in the photocycle of Y185F was identified on the basis of characteristic chromophore and protein vibrational bands. As N decays, bands characteristic of the all‐trans O chromophore appear in the time‐resolved FTIR difference spectra in the same time range as the appearance of a red‐shifted photocycle intermediate absorbing near 640 nm. Based on our previous assignment of the carboxyl stretch bands to the four membrane embedded Asp groups: Asp‐85, Asp‐96, Asp‐115 and Asp‐212, we conclude that during O formation: (i) Asp‐96 undergoes reprotonation. (ii) Asp‐85 may undergo a small change in environment but remains protonated. (iii) Asp‐212 remains partially protonated. In addition, reisomerization of the chromophore during the N→O transition is accompanied by a major reversal of protein conformational changes which occurred during the earlier steps in the photocycle. These results are discussed in terms of a proposed mechanism for proton transport.
PHOTOSELECTION AND TRANSIENT LINEAR DICHROISM WITH ORIENTED IMMOBILIZED PURPLE MEMBRANES: EVIDENCE FOR MOTION OF THE C(20)‐METHYL GROUP OF THE CHROMOPHORE TOWARDS THE CYTOPLASMIC SIDE OF THE MEMBRANE*
Authors: Heyn Maarten P. , Otto Harald
Published: March 2008

Abstract— We have determined the transition dipole moment orientation of the chromophore during the photocycle of bacteriorhodopsin by photoselection and time‐resolved linear dichroism experiments with samples of oriented immobilized purple membranes. This technique offers two important advantages over experiments with isotropic aqueous suspensions: (1) the depolarization due to the rotational diffusion of the membranes is eliminated, (2) the sensitivity for detecting the orientation of the transition dipole moment of intermediates is greatly increased. The appropriate equations for the analysis of time‐resolved linear dichroism experiments with samples of oriented immobilized membranes will be presented. In the transition from the ground state of bacteriorhodopsin to the M‐intermediate, the transition dipole moment tilts out of the plane of the membrane by about 3°. On the basis of current structural information on the plane of the chromophore and the orientation of its C(19) and C(20) methyl groups, a tilt of the transition dipole moment into the plane of the membrane would have been expected if it is assumed that the orientation of the conjugated polyene chain from C(5) to C(13) is the same in both states. The experimental result may be explained by an 11° tilt of the C(5) to C(13) part of the chain out of the plane of the membrane with the C(20) methyl group moving towards the cytoplasmic side of the membrane by about 1.7 Å and the cyclohexene ring staying fixed. This interpretation is supported by recent neutron diffraction experiments on the chromophore position in the M‐intermediate.
LIGHT‐SENSITIVITY MODULATING PROTEIN IN FROG RODS
Authors: Kawamura Satoru
Published: March 2008

Abstract— Cyclic GMP is the second messenger in the phototransduction mechanism in rod photo‐receptors. Light‐induced activation of cGMP phosphodiesterase (PDE), the hydrolyzing enzyme of cGMP, reduces cytoplasmic cGMP concentration to close the cGMP‐activated channel and thereby causes a hyperpolarizing light response. Ca2+ concentration decreases during light‐adaptation and this decrease is thought to be at least one of the underlying mechanisms of light‐adaptation. Our previous electrophysiological work suggested that PDE in frog rod photoreceptors is regulated by this Ca2+ concentration decrease. In the present work, we isolated a protein that binds to disk membranes at high Ca2+ concentrations. In the presence of this protein (a 26 kDa protein), PDE light sensitivity becomes high at high Ca2+ concentrations. The effect was observed at physiological ranges of Ca2+ concentrations. Thus we could explain high light‐sensitivity of photoreceptors under the dark‐adapted condition. According to its function, we termed the 26 kDa protein ‘sensitivity‐modulating protein’ or ‘S‐modulin’. During the purification we noticed that there are additional mechanisms present that may contribute to light‐adaptation in frog rod photoreceptors.
Evaluation of a rapid agglutination method for detection of equine red cell surface antigens (Ca and Aa) as part of pretransfusion testing
Authors: Owens Sean D. , Snipes Joy , Magdesian K. Gary , Christopher Mary M.
Published: March 2008

Background: Blood typing before transfusion minimizes the risk of transfusion reactions and prevents immunization of the recipient against incompatible RBC antigens. The major RBC antigens that warrant identification before packed RBC or whole blood transfusions in horses are Ca and Aa. Standard blood‐typing protocols are time‐consuming (2.5–3.0 hours) and impractical in emergency settings.

Objectives: The purpose of this study was to determine whether equine RBCs could be typed for Ca and Aa antigens using sera from horses with RBC antibodies in a modified rapid (15 minute) blood‐typing protocol.

Methods: Serum was obtained from a horse with anti‐Ca antibodies and from another horse with anti‐Aa antibodies. The presence of agglutinating antibodies was confirmed with antibody screening. Venous blood samples, collected in citrate–phosphate–dextrose, were obtained from 21 horses of various breeds. Samples were blood typed in the Veterinary Medical Teaching Hospital Hematology Laboratory using standard methodology. Washed RBCs from each of the 21 horses were incubated individually with anti‐Ca and anti‐Aa sera at dilutions of 1:4, 1:8, and 1:16 for 15 and 30 minutes at room temperature and 37 °C.

Results: Of the 21 horses, 13 were identified as Aa+/Ca+, four were Aa+/Ca−, two were Aa−/Ca+, and two were Aa−/Ca−. All 17 Aa‐positive horses had a positive agglutination reaction at all dilutions of anti‐Aa serum, incubation times, and temperatures, while all Aa‐negative horses were negative. Each Ca‐positive horse had a positive agglutination reaction at all incubation time points and temperatures up to the 1:16 dilution of the anti‐Ca serum. All Ca‐negative horses were negative at all times, temperatures, and dilutions of anti‐Ca serum. Use of the modified protocol on 26 hospitalized horses resulted in accurate typing, based on complete antibody screens.

Conclusions: These results support the hypothesis that equine RBCs can be blood typed using a rapid (15 minute) protocol, at room temperature, for the presence of Ca and Aa antigens using equine‐derived antisera. This technique may be beneficial for pretransfusion testing of equine patients in an emergency setting.
A multicentric retrospective study of serum/plasma urea and creatinine concentrations in dogs using univariate and multivariate decision rules to evaluate diagnostic efficiency
Authors: Concordet D. , Vergez F. , Trumel C. , Diquélou A. , Lanore D. , Le Garrérès A. , Pagès J. P. , Péchereau D. , Médaille C. , Braun J. P.
Published: March 2008

Background: Urea and creatinine are the most frequently used indirect markers in plasma and serum of glomerular filtration rate in dogs. Both have been shown to lack sensitivity but their diagnostic efficiency for the diagnosis of kidney disease has been minimally investigated.

Objective: The purpose of this retrospective study was to investigate the influence of possible factors of variation on both analytes and to determine whether specific decision rules should be drawn up for subpopulations of dogs.

Methods: The results of urea and creatinine measurements, breed, sex, age, and health status (healthy, renal disease, or nonrenal disease) of 3822 dogs were collected from the archives of 5 veterinary clinics. Data were analyzed with univariate and multivariate decision rules with and without adjustment.

Results: There were significant effects and interactions of almost all of the sources of variation. Slight improvements in diagnostic efficiency were obtained by adjusting the decision rules to these sources of variations. Univariate decision rules gave approximately the same diagnostic efficiency for urea and creatinine concentrations, with sensitivity and specificity in the range of 70% and 90%, respectively, using the upper limit of the reference interval as the threshold value. Multivariate decision rules provided only minor improvements in diagnostic efficiency.

Conclusion: Simultaneous measurement of both urea and creatinine is of limited diagnostic value over the analysis of a single variable. Creatinine is the preferred analyte as it is affected by fewer extrarenal factors of variation.
Serum amyloid A is not a marker for relapse of multicentric lymphoma in dogs
Authors: Merlo Alexandre , Rezende Bárbara Cristina Gagliano , Franchini Maria Luisa , Monteiro Paula Rumy Gonçalves , Lucas Sílvia Regina Ricci
Published: March 2008

Background:Serum amyloid A (SAA) is an acute phase protein whose concentration increases in inflammatory, infectious, and neoplastic conditions in animals and human beings. Multicentric lymphoma is a common cancer in dogs, and chemotherapy is indicated to attain long‐term survival. However, frequent relapses lead to changes in chemotherapeutic protocols.

Objectives:The aims of this study were to evaluate SAA as a marker for relapse of multicentric lymphoma in dogs and to determine whether chemotherapy induces changes in the concentration of SAA during treatment.

Methods:SAA was measured by an ELISA test in healthy control dogs (n=20), in healthy dogs receiving chemotherapy (n=8), and in dogs with lymphoma (n=20). All dogs receiving chemotherapy were randomly assigned to 2 treatment groups, one receiving cyclophosphamide, vincristine, and prednisone (CVP) and the other receiving vincristine, cyclophosphamide, methotrexate, andl‐asparaginase (VCMA) protocols. SAA concentration was determined before chemotherapy at weeks 1–4 in healthy dogs receiving chemotherapy and in dogs with lymphoma, then every 3 weeks for 4 months in healthy dogs, and at relapse and in the sample prior to relapse in dogs with lymphoma. SAA was measured only once in the healthy control dogs. Results were analyzed using repeated measures ANOVA followed by Tukey multiple comparison tests to compare groups and weeks of treatment.

Results:Mean SAA concentration was significantly higher in dogs with lymphoma before chemotherapy compared with healthy and chemotherapy control dogs. No increase in SAA concentration was found at relapse. No differences were observed in SAA concentration based on type of chemotherapy protocol.

Conclusions:SAA is not a marker of relapse in dogs with multicentric lymphoma, nor does chemotherapy regimen affect SAA concentration.
POSITIVE MAGNETO-RESISTANCE IN A POINT CONTACT: POSSIBLE MANIFESTATION OF INTERACTIONS
Authors: RENARD V. T. , OTA T. , KUMADA N. , HIRAYAMA H.
Published: March 2008

We report a non-monotonic and strongly temperature dependent magneto-resistance observed in clean quantum point contacts. At the same time the conductance of the point contact varies linearly with temperature. This unexpected behavior may be related to electron-electron interactions.
CHARACTERIZATION OF VOLTAGE-CONTROLLED OSCILLATOR USING RTD TRANSMISSION LINE
Authors: NARAHARA KOICHI , YAMAKI TAKUO , TAKAHASHI TATSUNORI , NAKAMICHI TORU
Published: March 2008

Widely-tunable voltage-controlled oscillator using resonant tunneling diodes in a distributed manner is discussed. The circuit configuration and the principle of operation of the VCO are described together with several results of numerical calculations, which include necessary condition of permanent oscillation and how much the oscillation frequency is tuned by the voltage.
MAGNETORESISTANCE IN Fe/MgO/Fe MAGNETIC TUNNEL JUNCTIONS
Authors: BELETSKII N. N. , BORYSENKO S. A. , YAKOVENKO V. M. , BERMAN G. P. , WOLF S. A.
Published: March 2008

The magnetoresistance of Fe/MgO/Fe magnetic tunnel junctions (MTJs) was studied taking into consideration image forces. For MTJs with an MgO insulator, explanations are given of the giant tunneling magnetoresistance (TMR) effect and the effect of the increasing TMR with an increase in MgO insulator thickness. It is demonstrated that the electron current density through MTJs can be high enough to switch the magnetization of a ferromagnetic electrode.
QUANTUM ENGINEERING FOR THREAT REDUCTION AND HOMELAND SECURITY
Authors: BERMAN GENNADY P. , BISHOP ALAN R. , CHERNOBROD BORIS M.
Published: March 2008

We review the results of our current research on quantum engineering which include the theory, modeling and simulations of quantum devices for potential applications to threat reduction and homeland security. In particular, we discuss: (i) scalable solid-state quantum computation with qubits based on (a) nuclear spins of impurity atoms in solids, (b) superconducting junctions, and (c) unpaired electron spins of spin radicals in self-assembled organic materials; (ii) quantum neural devices; (iii) quantum annealing; (iv) novel magnetic memory devices based on magnetic tunneling junctions with large tunneling magnetoresistance; (v) terahertz detectors based on microcantilever as a light pressure sensor; (vi) BEC based interferometers; (vii) quantum microscopes with a single-spin resolution based on (a) a magnetic resonant force microscopy and (b) an optically detected magnetic resonance; and (viii) novel approach for suppression of fluctuations in free space high-speed optical communication. Finally, we describe the similarities between the behavior of cross sections in reactions with heavy nuclei in the regions of strongly overlapped resonances and electron conductivity in semiconductor heterostructures.
APPROXIMATELY INDEPENDENT FEATURES OF LANGUAGES
Authors: HOLMAN ERIC W.
Published: March 2008

To facilitate the testing of models for the evolution of languages, the present paper offers a set of linguistic features that are approximately independent of each other. To find these features, the adjusted Rand index (R′) is used to estimate the degree of pairwise relationship among 130 linguistic features in a large published database. Many of the R′ values prove to be near zero, as predicted for independent features, and a subset of 47 features is found with an average R′ of -0.0001. These 47 features are recommended for use in statistical tests that require independent units of analysis.
DEMOGRAPHIC GROWTH AND THE DISTRIBUTION OF LANGUAGE SIZES
Authors: ZANETTE DAMIÁN H.
Published: March 2008

It is argued that the present log-normal distribution of language sizes is, to a large extent, a consequence of demographic dynamics within the population of speakers of each language. A two-parameter stochastic multiplicative process is proposed as a model for the population dynamics of individual languages, and applied over a period spanning the last ten centuries. The model disregards language birth and death. A straightforward fitting of the two parameters, which statistically characterize the population growth rate, predicts a distribution of language sizes in excellent agreement with empirical data. Numerical simulations, and the study of the size distribution within language families, validate the assumptions at the basis of the model.
QUATERNION ALGEBRAS AND INVARIANTS OF VIRTUAL KNOTS AND LINKS II: THE HYPERBOLIC CASE
Authors: BUDDEN STEPHEN , FENN ROGER
Published: March 2008

Let A, B be invertible, non-commuting elements of a ring R. Suppose that A - 1 is also invertible and that the equation [Formula: see text] called the fundamental equation is satisfied. Then an invariant R-module is defined for any diagram of a (virtual) knot or link. Solutions in the classic quaternion case have been found by Bartholomew, Budden and Fenn. Solutions in the generalized quaternion case have been found by Fenn in an earlier paper. These latter solutions are only partial in the case of 2 × 2 matrices and the aim of this paper is to provide solutions to the missing cases.
ON GENERALIZED KNOT GROUPS
Authors: LIN XIAO-SONG , NELSON SAM
Published: March 2008

Generalized knot groups Gn(K) were introduced first by Wada and Kelly independently. The classical knot group is the first one G1(K) in this series of finitely presented groups. For each natural number n, G1(K) is a subgroup of Gn(K) so the generalized knot groups can be thought of as extensions of the classical knot group. For the square knot SK and the granny knot GK, we have an isomorphism G1(SK) ≅ G1(GK). From the presentations of Gn(SK) and Gn(GK), for n > 1, it seems unlikely that Gn(SK) and Gn(GK) would be isomorphic to each other. Curiously, we are able to show that for any finite group H, the numbers of homomorphisms from Gn(SK) and Gn(GK) to H, respectively, are the same. Moreover, the numbers of conjugacy classes of homomorphisms from Gn(SK) and Gn(GK) to H, respectively, are also the same. It remains a challenge to us to show, as we would like to conjecture, that Gn(SK) and Gn(GK) are not isomorphic to each other for all n > 1.
SMOLYANOV–WEIZSÄCKER SURFACE MEASURES GENERATED BY DIFFUSIONS ON THE SET OF TRAJECTORIES IN RIEMANNIAN MANIFOLDS
Authors: TELYATNIKOV ILYA V.
Published: March 2008

We consider surface measures on the set of trajectories in a smooth compact Riemannian submanifold of Euclidean space generated by diffusion processes in the ambient space. A construction of surface measures on the path space of a smooth compact Riemannian submanifold of Euclidean space was introduced by Smolyanov and Weizsäcker for the case of the standard Brownian motion. The result presented in this paper extends the result of Smolyanov and Weizsäcker to the case when we consider measures generated by diffusion processes in the ambient space with nonidentical correlation operators. For every partition of the time interval, we consider the marginal distribution of the diffusion process in the ambient space under the condition that it visits the manifold at all times of the partition, when the mesh of the partition tends to zero. We prove the existence of some limit surface measures and the equivalence of the above measures to the distribution of some diffusion process on the manifold.
UNCERTAINTY PRINCIPLE FOR WIGNER–YANASE–DYSON INFORMATION IN SEMIFINITE VON NEUMANN ALGEBRAS
Authors: GIBILISCO PAOLO , ISOLA TOMMASO
Published: March 2008

In Ref. 9, Kosaki proved an uncertainty principle for matrices, related to Wigner–Yanase–Dyson information, and asked if a similar inequality could be proved in the von Neumann algebra setting. In this paper we prove such an uncertainty principle in the semifinite case.
A Random Coding Based Proof for the Quantum Coding Theorem
Authors: Klesse Rochus
Published: March 2008

We present a proof for the quantum channel coding theorem which relies on the fact that a randomly chosen code space typically is highly suitable for quantum error correction. In this sense, the proof is close to Shannon's original treatment of information transmission via a noisy classical channel.