bluuebunny/crossref_metadata_2025 huggingface dataset:
Sparse ordinal logistic regression and its application to brain decoding
Authors: Satake Emi , Majima Kei , Aoki Shuntaro C , Kamitani Yukiyasu
Published: December 2017

Brain decoding with multivariate classification and regression has provided a powerful framework for characterizing information encoded in population neural activity. Classification and regression models are respectively used to predict discrete and continuous variables of interest. However, cognitive and behavioral parameters that we wish to decode are often ordinal variables whose values are discrete but ordered, such as subjective ratings. To date, there is no established method of predicting ordinal variables in brain decoding. In this study, we present a new algorithm, sparse ordinal logistic regression (SOLR), that combines ordinal logistic regression with Bayesian sparse weight estimation. We found that, in both simulation and analyses using real functional magnetic resonance imaging data, SOLR outperformed ordinal logistic regression with non-sparse regularization, indicating that sparseness leads to better decoding performance. SOLR also outperformed classification and linear regression models with the same type of sparseness, indicating the advantage of the modeling tailored to ordinal outputs. Our results suggest that SOLR provides a principled and effective method of decoding ordinal variables.
Stimulus content shapes cortical response statistics
Authors: Bányai Mihály , Lazar Andreea , Klein Liane , Klon-Lipok Johanna , Singer Wolf , Orbán Gergő
Published: December 2017

Spike count correlations (SCCs) are ubiquitous in sensory cortices, are characterized by rich structure and arise from structured internal interactions. Yet, most theories of visual perception focus exclusively on the mean responses of individual neurons. Here, we argue that feedback interactions in primary visual cortex (V1) establish the context in which individual neurons process complex stimuli and that changes in visual context give rise to stimulus-dependent SCCs. Measuring V1 population responses to natural scenes in behaving macaques, we show that the fine structure of SCCs is stimulus-specific and variations in response correlations across-stimuli are independent of variations in response means. Moreover, we demonstrate that stimulus-specificity of SCCs in V1 can be directly manipulated by controlling the high-order structure of synthetic stimuli. We propose that stimulus-specificity of SCCs is a natural consequence of hierarchical inference where inferences on the presence of high-level image features modulate inferences on the presence of low-level features.
MateSim: Monte Carlo simulation for the generation of mating tables
Authors: Carvajal-Rodríguez A.
Published: December 2017

In species with sexual reproduction, the mating pattern is a meaningful element for understanding evolutionary and speciation processes. Given a mating pool where individuals can encounter each other randomly, the individual mating preferences would define the mating frequencies in the population. However, in every mating process we can distinguish two different steps. First, the encounter between partners. Second, the actual mating once the encounter has occurred. Yet, we cannot always assume that the observed population patterns accurately reflect the individual’s preferences. In some scenarios the individuals may have difficulties to achieve their preferred matings, such as in monogamous species with low population size, where the mating process is similar to a sampling without replacement. In the latter, the encounter process will introduce some noise that may disconnect the individual preferences from the obtained mating pattern. Actually, the difference between the mating pattern observed in a population and the mating preferences of the individuals have been shown by different modeling scenarios.

Here I present a program that simulates the mating process for both discrete and continuous traits, under different encounter models and individual preferences, including effects as time dependence and aging. The utility of the software is demonstrated by replicating and extending, a recent study that showed how patterns of positive assortative mating, or marriage in human societies, may arise from non-assortative individual preferences. The previous result is confirmed and is shown to be caused by the marriage among the “ugliest” and oldest individuals, who after many attempts were finally able to mate among themselves. In fact, I show that the assortative pattern vanishes if an aging process prevents these individuals from mating altogether. The software MateSim is available jointly with the user’s manual, at http://acraaj.webs.uvigo.es/MateSim/matesim.htm
Automated 3D Axonal Morphometry of White Matter
Authors: Abdollahzadeh Ali , Belevich Ilya , Jokitalo Eija , Tohka Jussi , Sierra Alejandra
Published: December 2017

Axonal structure underlies white matter functionality and plays a major role in brain connectivity. The current literature on the axonal structure is based on the analysis of two-dimensional (2D) cross-sections, which, as we demonstrate, is precarious. To be able to quantify three-dimensional (3D) axonal morphology, we developed a novel pipeline, called ACSON (AutomatiC 3D Segmentation and morphometry Of axoNs), for automated 3D segmentation and morphometric analysis of the white matter ultrastructure. The automated pipeline eliminates the need for time-consuming manual segmentation of 3D datasets. ACSON segments myelin, myelinated and unmyelinated axons, mitochondria, cells and vacuoles, and analyzes the morphology of myelinated axons. We applied the pipeline to serial block-face scanning electron microscopy images of the corpus callosum of sham-operated (n = 2) and brain injured (n = 3) rats 5 months after the injury. The 3D morphometry showed that cross-sections of myelinated axons were elliptic rather than circular, and their diameter varied substantially along their longitudinal axis. It also showed a significant reduction in the myelinated axon diameter of the ipsilateral corpus callosum of rats 5 months after brain injury, indicating ongoing axonal alterations even at this chronic time-point.
“CapZyme-Seq” comprehensively defines promoter-sequence determinants for RNA 5’ capping with NAD+
Authors: Vvedenskaya Irina O. , Bird Jeremy G. , Zhang Yuanchao , Zhang Yu , Jiao Xinfu , Barvík Ivan , Krásný Libor , Kiledjian Megerditch , Taylor Deanne M. , Ebright Richard H. , Nickels Bryce E.
Published: December 2017

Nucleoside-containing metabolites such as NAD+can be incorporated as “5′ caps” on RNA by serving as non-canonical initiating nucleotides (NCINs) for transcription initiation by RNA polymerase (RNAP). Here, we report “CapZyme-Seq,” a high-throughput-sequencing method that employs NCIN-decapping enzymes NudC and Rai1 to detect and quantify NCIN-capped RNA. By combining CapZyme-Seq with multiplexed transcriptomics, we determine efficiencies of NAD+capping byEscherichia coliRNAP for ~16,000 promoter sequences. The results define preferred transcription start-site (TSS) positions for NAD+capping and define a consensus promoter sequence for NAD+capping: HRRASWW (TSS underlined). By applying CapZyme-Seq toE. colitotal cellular RNA, we establish that sequence determinants for NCIN cappingin vivomatch the NAD+-capping consensus definedin vitro, and we identify and quantify NCIN-capped small RNAs. Our findings define the promoter-sequence determinants for NCIN capping with NAD+and provide a general method for analysis of NCIN cappingin vitroandin vivo.
The continuous flow culture as an in vitro model in experimental mycology
Authors: Bernhardt Hannelore , Zimmermann Kathrin , Knoke M.
Published: December 2017

We used the model of continuous flow culture (cfc) to study the growth of Candida species. This model allows special test conditions: a long generation time of 15–20 hs, controlled limitation of nitrogen sources and carbohydrates, comparison of the growth under aerobic and anaerobic conditions simultaneously. These conditions were used to study the effect of antimycotic drugs, mainly during a long time of 7 to 10 days.

Germ tube formation as a virulence factor was more abundant and faster in cfc of strains with a stronger adherence to buccal epithelium cells. Co‐cultivation of C. albicans and C. glabrata allowed conclusions for their colonization in vivo. A biofilm on the glass wall of the culture vessel led to mycelium formation by C. albicans. Concomitantly the growth of C. glabrata was favoured. Growth of C. albicans in the gastrointestinal flora was reduced by masses of bacteria and their multiple metabolic activities. A remarkable growth of C. albicans was only to be seen if the ecosystem was destroyed e.g. by antibacterial antibiotics. The influence of fluconazole in a long‐term follow up study under anaerobic conditions showed an inhibition of C. albicans in 99.9 %. This means fungicidal efficacy.
Cutaneous sporotrichosis in Thailand: first reported case
Authors: Kwangsukstith C. , Vanittanakom N. , Khanjanasthiti P. , Uthammachai C.
Published: December 2017

A case of cutaneous sporotrichosis is reported for the first time in Thailand. The infection occurred in a 33‐ year‐old Thai female who has been in good health and had no history of previous trauma or contact with any animals. Histopathology revealed pseudoepitheliomatous hyperplasia of the epidermis and a combination of granulomatous and pyogenic reactions in the dermis and subcutaneous tissue. Typical asteroid bodies (Splendore‐Hoeppli phenomenon) with central yeast cells were seen. Sporothrix schenckii was recovered from skin biopsy specimens. The patient responded well to the treatment with saturated solutions of potassium iodide within three months. No recurrence was seen after more than six months follow‐up.
In Vitro Susceptibility of Dermatophytes from Munich to Griseofulvin, Miconazole and Ketoconazole
Authors: Korting H. C. , Rosenkranz Simone
Published: December 2017

Various recent clinical isolates of Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis and Epidermophyton floccosum from Munich were subjected to antimicrobial susceptibility testing using the microdilution method. Both azoles miconazole and ketoconazole were found to be more active than griseofulvin. Comparatively high inhibitory concentrations of griseofulvin were especially found with Tr. mentagrophytes. On the whole miconazole turned out to be even somewhat more effective than ketoconazole. Considering the minimum inhibitory concentrations found at least some of the strains tested might not be open to eradication in clinical terms with conventional treatment protocols.
Induction of zoospore formation in Thai isolates of Pythium insidiosum
Authors: Chaiprasert A. , Samerpitak K. , Wanachiwanawin W. , Thasnakorn P.
Published: December 2017

Three human isolates of Pythium insidiosum De Cock 1987, the aetiologic agent of pythiosis, were induced for zoosporogenesis. The isolates were grown on Sabouraud glucose agar for 2 days before being inoculated into boiled spikelets of Axonopus compressus (Gramineae) and then into induction medium (IM). Optimum zoospore formation was demonstrated under the light microscope after incubation for 24 h at 37°C in IM.
Pulmonary fungal infections in immunocompromised patients: incidence and risk factors
Authors: von Eiff M. , Roos N. , Fegeler W. , von Eiff C. , Zühlsdorf M. , Glaser J. , van de Loo J.
Published: December 2017

In a prospective study, 178 patients with fever > 38.4 °C and newly diagnosed pulmonary infiltrates underwent bronchoscopy with bronchoalveolar lavage (BAL), aspiration of bronchial secretions (BS) and, in 71 cases, protected specimen brushing (PSB). In 42/143 immunocom‐promised patients (haematological malignancies, n= 92; AIDS, n = 22; immunosuppressant therapy, n = 29) and in 4/35 patients with no defined underlying disease fungal pneumonia was present (candidosis, n= 35; aspergillosis, n = 8 mixed fungal infection, n = 3). Candidosis was combined, in 17 cases, with Aspergillus (n=3), bacterial (n= 15) or cytomegalovirus (n=2) infection. Aspergillosis was combined in eight cases with infection with Candida (n = 3), Pneumocystis carinii (n=1) or bacteria (n = 5). The sensitivity of BAL and PSB in Candida pneumonia was 48% and 50%, respectively; specificity was 75% and 74% respectively. Bronchial secretions were more sensitive in detecting Candida pneumonia, but specificity was only 55%. In aspergillosis, the specificity of BAL, BS and PSB in each case was 100%; the sensitivity of BAL, BS and PSB was 38%, 64% and 100%. Twenty‐four fungal infections were fatal. Unfavourable prognostic factors were respiratory failure needing mechanical ventilation, diffuse bilateral pulmonary infiltrates, mixed fungal infections and start of i.v. antifungal treatment > 14 days after fever onset, which were associated with a mortality rate of 74%, 67%, 67% and 63% respectively.
Doctors with Asperger's: the impact of a diagnosis
Authors: Price Sophie , Lusznat Rosie , Mann Richard , Locke Rachel
Published: December 2017

Background

Asperger syndrome (AS) is part of a spectrum of disorders encompassing difficulties with social interaction that may result in specific educational needs for doctors in training. There is currently limited research on the impact of AS on working as a doctor.

Methods

This is a qualitative study using semi‐structured interviews to explore the perceptions of trainees diagnosed with AS following input from a professional support service, and the perspectives of the staff involved in their professional development.

Findings

Receiving a diagnosis of AS was viewed as a double‐edged sword, allowing the development of insight into lifelong difficulties, but also creating the potential for prejudice. Understanding AS traits provided an explanation for challenges in the workplace and therefore opportunities to find solutions.

Understanding AS traits provided an explanation for challenges in the workplace

Discussion

This study explores the benefits and disadvantages of defining and labelling a specific professional support need for a group of trainees. It also reveals the need for improved awareness of AS amongst all clinical educators.
The structure of one weight linear and cyclic codes over Z_{2}^r x (Z_{2} + uZ_{2})^s
Authors: Aydogdu Ismail
Published: December 2017

Inspired by the Z2Z4-additive codes, linear codes over Z_{2}^r x  (Z_{2} + uZ_{2})^s have been introduced by Aydogdu et al. more recently. Although these family of codes are similar to each other, linear codes over Z_{2}^r x  (Z_{2} + uZ_{2})^s have some advantages compared to Z2Z4-additive codes. A code is called constant weight(one weight) if all the codewords have the same weight. It is well known that constant weight or one weight codes have many important applications. In this paper, we study the structure of one weight Z2Z2[u]-linear and cyclic codes. We classify these type of one weight codes and also give some illustrative examples.
Can technology replace live preparations in student laboratories?
Authors: Modell H I
Published: December 2017

We have seen a trend in recent years toward reduction or elimination of student laboratories in many physiology curricula. Some departments have sought "alternatives" to live preparations in an attempt to retain an active learning experience for students. However, it seems as if few departments have seriously examined the specific educational objectives of their student laboratories to determine whether alternatives exist that will allow these objectives to be met. Technology certainly offers a variety of ways to provide active learning experiences. In some instances, technological approaches can be used to address the same educational objectives as traditional laboratories, while in others these objectives may be partially met by use of technology. However, it is important to recognize that some educational objectives can only be achieved through first-hand experience with live preparations.
Human situations: a course introducing physiology to medical students.
Authors: Hansen P A , Roberts K B
Published: December 2017

A block course of 12 days is described. It is considered to be appropriate for both physiologically naive and sophisticated students entering either a traditional or a problem-based curriculum. It is adaptable for medical schools in both developed and developing countries. Six problem-based small-group sessions, based on everyday human situations, are the core of the course. They are supplemented by a lecture series, laboratory experiments using student volunteers as subjects, laboratory demonstrations, and patient presentations. Student assessment is carried out by criterion-referenced examinations using take-home assignments, oral examinations, and a multiple-choice test containing context-dependent questions. The course is well received by students and faculty. Pre- and posttesting show that all students acquire a basic understanding of physiological control systems and of homeostatic mechanisms as they operate in intact human beings.
Teaching medical physiology in Brazil.
Authors: Bartoszeck A B
Published: December 2017

An analysis of physiology teaching in Brazil is carried out based on data collected from a questionnaire sent to 78 medical schools. It investigates faculty graduate degrees, time spent on teaching, audiovisual equipment available, evaluation of student performance, books in current use, and areas of research. Local results as compared with those from an international sample have shown a preference for lectures and that large departments are more concerned with research, but changes are underway to introduce computer simulations and modular instruction as a means to improve teaching.
Project labs in physiology.
Authors: Woodhull-McNeal A P
Published: December 2017

Projects in which students design and carry out their own experiments can be a basis for physiology laboratories. A sequence of such projects is described and evaluated informally. It is argued that these inquiry-oriented project labs serve to motivate and teach students important concepts and attitudes about the nature of science and their ability to participate actively in it. Although physiology laboratories are a standard part of physiology courses, teachers are not always clear about the purposes of these activities. At least three categories of purpose seem important: the conceptual, the motivational, and the technical. As laboratories are being replaced in some cases by videodisc or computer simulations, it is important to see which purposes can be served by simulations and which cannot. Project-based laboratories, even more than standard laboratories, can serve the technical, motivational, and conceptual purposes for our laboratory teaching.
A faculty research and training program for undergraduates in the sciences.
Authors: Randall W C , Burden S L
Published: December 2017

Faculty enthusiasm, with actual hands-on involvement, is a critical factor in establishing student research interest and excitement in a university or college science environment. Such faculty involvement is infectious to students and therefore key to restoring United States leadership in science and technology in the next decades. Most scientists acknowledge that they were initially attracted into scientific careers through one or two notable teachers who served as role models. However, with the introduction of so-called "big science" and its distraction of university faculty away from meaningful, direct student contacts, and with associated withdrawal of funding from "little science" in the college teacher's laboratory, research languishes in nearly all undergraduate teaching institutions. The inspiring college science teacher seems essentially gone, tired or burnt out, unable to keep pace with the rigorous demands of an active research lab while simultaneously meeting the exhausting load of 15-18 (or more) contact teaching hours per week. With all of the associated lecture preparations, student counseling, and Dean's committee assignments, the teacher has little or no scholarly "think time" or opportunity to inspire even the bright students. Without the teacher's honest and evident involvement and deep commitment, the student fails to experience the essential impact of a convincing role model. It is therefore necessary to restore the college science teacher's opportunity and aspirations to be personally involved in research. This can only be accomplished by providing time, facilities, incentives, and encouragement to do what originally attracted the teacher into a career in science and teaching in the first place.(ABSTRACT TRUNCATED AT 250 WORDS)
The Predictions Table: a tool for assessing students' knowledge.
Authors: Rovick A A , Michael J A
Published: December 2017

The Predictions Table (PT), a tool for determining students' knowledge, is described. The PT is a matrix consisting of a group of variables and a set of time periods. Students enter in the PT their qualitative predictions of the effects of a perturbation on a physiological system. The instructor or a teaching program can then evaluate the students' knowledge from these entries. An example is given from the teaching program CIRCSIM, which deals with blood pressure regulation. It shows the way that the program uses errors in the students' PT entries. CIRCSIM was evaluated and was found to have a statistically significant effect. It reduced the number of errors that students made in predicting the responses of the cardiovascular system to a perturbation. Also, students who worked in groups had significantly greater improvement than did control students. Using CIRCSIM also significantly reduces the number of relationship errors that the students make. They made even fewer errors when an instructor was present in the computer classroom while the students used CIRCSIM.
The life and death of laboratory teaching of medical physiology: a personal narrative. Part I.
Authors: Davenport H W
Published: December 2017

Part I of this essay sketches the history of laboratory teaching of medical physiology in England from the perspective of the author as a student at Oxford from 1935 to 1938. The systematic laboratory teaching that began in the 1870s at University College London under William Sharpey was carried to Oxford, as well as to other English and Scottish universities, by Sharpey's junior colleagues. C. S. Sherrington added mammalian experiments, and C. G. Douglas and J. G. Priestley added experiments on human subjects. The author describes his experience as a student in the Oxford courses and tells how he learned physiology by teaching it from 1941 to 1943 in the laboratory course established at the University of Pennsylvania by Oxford-trained physiologist Cuthbert Bazett.
Case-stimulated learning within endocrine physiology lectures: an approach applicable to other disciplines.
Authors: Walters M R
Published: December 2017

The problem of presenting endocrine physiology lectures in a format that interests medical students was addressed. Incorporating truncated case-stimulated learning sessions into the lectures has proven to be a successful solution to this issue, while also providing continuity between topics in the lecture block. This method of providing a direct clinical link for basic physiological concepts and providing a more active learning experience is adaptable to most basic science disciplines.
Unilateral nephrectomy in the rat as a teaching model of renal function.
Authors: Zwemer C F
Published: December 2017

The white rat offers a valuable teaching model to demonstrate the in situ anatomy, homeostatic control, and function of the mammalian renal system. Students in the upper-level physiology class at Dickinson College are responsible for formulating a set of testable hypotheses as to the possible compensatory mechanisms that will result from a unilateral nephrectomy in the rat. To test their hypotheses, each group of students is made responsible for induction and maintenance of anesthesia, removal of the left kidney, closure, and recovery of the animal in their experiment. Before and 1 wk after nephrectomy, blood samples are collected via tail section for measurement of hematocrit and plasma creatinine concentrations. Pooling data across all student groups (n = 6) for pre- and postnephrectomy hematocrit and creatinine values allows students to run statistical comparisons testing their hypotheses. This laboratory experience in integrative physiology is a successful exercise in introducing fundamentals of experimental design and, most importantly, provides students with an appreciation for the process of humane use of animals in research and teaching.
Refresher course for teaching cardiovascular physiology.
Authors: Belloni F L
Published: December 2017

This report presents highlights of a refresher course presented at Experimental Biology '99 on Saturday, April 17, 1999, in Washington, District of Columbia.
Teaching vascular adaptations to mechanical stress.
Authors: Prewitt R L
Published: December 2017

Blood vessels change their number and structure in attempt to meet tissue demands for blood flow while simultaneously controlling mechanical stresses. A great deal of information is emerging in this field, especially concerning the role of the endothelium and signaling pathways for mechanotransduction. While not delving too deeply into the rapidly changing details, the students can be introduced to this exciting field by describing the structural changes that take place and outlining the major theories that are being investigated. The applications to peripheral vascular disease, myocardial infarctions, hypertension and tumor growth are readily apparent.
A simplified paired neck chamber for the demonstration of baroreflex blood pressure regulation.
Authors: Raine N M , Cable N T
Published: December 2017

In this investigation a simplified variable-pressure paired neck chamber was developed as a practical alternative to traditional neck collar designs used to study the arterial baroreceptor reflex in humans. The purpose of this new design was to extend the use of the noninvasive neck chamber method of baroreceptor investigation to teachers of physiology. Performance tests indicate that these new chambers are capable of delineating the stimulus-response relationship for both the blood pressure baroreflex [sensitivity = 0.425 +/- 0.13 mmHg mean arterial pressure (MAP)/mmHg neck chamber pressure (NCP); range = 24.9 +/- 4.6 mmHg MAP] and the heart rate baroreflex (sensitivity 0.273 +/- 0.12 beats.min-1.mmHg NCP-1; range = 16.7 +/- 6.8 beats/min). This was achieved by applying localized positive and negative air pressures to the carotid sinuses throughout the range from +60 to -60 mmHg in steps of 20 mmHg. This simplified neck chamber method offers distinct methodological advantages over traditional neck collars, making it a valuable tool for demonstrating baroreflex regulation of the circulation.
A model circulatory system for use in undergraduate physiology laboratories.
Authors: Smith A M
Published: December 2017

The cardiovascular system is a central topic in physiology classes, yet it is difficult to provide undergraduates with quality laboratory experiences in this area. Thus a model circulatory system was developed to give students hands-on experience with cardiovascular fluid dynamics. This model system can be constructed from readily available materials at a reasonable cost. It has a realistic pressure drop across the different vessels. Using this system, students can investigate the effect that blood volume, vessel compliance, vessel construction, and heart activity have on blood pressure and flow. The system also demonstrates the effect of vessel diameter on resistance and fluid velocity. This model may give students a more concrete, intuitive feel for cardiovascular physiology. Another advantage is that it allows dramatic and easily controlled manipulations with quantitative results. Finally, its simple construction allows students to interchange components, giving them greater flexibility in experimentation.
Structural elements of kallistatin required for inhibition of angiogenesis
Authors: Miao Robert Q. , Chen Vincent , Chao Lee , Chao Julie
Published: December 2017

Kallistatin is a serpin first identified as a specific inhibitor of tissue kallikrein. Our recent studies showed that kallikrein promoted angiogenesis, whereas kallistatin inhibited angiogenesis and tumor growth. This study is aimed to identify the structural elements of kallistatin essential for its antiangiogenic function. Kallistatin mutants at the hinge region (A377T) and a major heparin-binding domain (K312A/K313A) were created by site-directed mutagenesis. Recombinant kallistatin mutant A377T did not bind or inhibit tissue kallikrein activity. Wild-type kallistatin and kallistatin mutant A377T, but not kallistatin mutant K312A/K313A lacking heparin-binding activity, inhibited VEGF-induced proliferation, growth, and migration of human microvascular endothelial cells. Similarly, wild-type kallistatin and kallistatin mutant A337T, but not kallistatin mutant K312A/K313A, significantly inhibited VEGF-induced capillary tube formation of cultured endothelial cells in Matrigel and capillary formation in Matrigel implants in mice. To elucidate the role of the heparin-binding domain in modulating angiogenesis, we showed that wild-type kallistatin interrupted the binding of 125I-labeled VEGF to endothelial cells, whereas kallistatin mutant K312A/K313A did not interfere with VEGF binding. Consequently, wild-type kallistatin, but not kallistatin mutant K312A/K313A, suppressed VEGF-induced phosphorylation of Akt. Taken together, these results indicate that the heparin-binding domain, but not the reactive site loop of kallistatin, is essential for inhibiting VEGF-induced angiogenesis.
Effect of nicotine on gastric acid secretion: evidence of electrogenic pump theory.
Authors: Dinno M A , Ando M , Dinno F H , Huang K C , Rehm W S
Published: December 2017

In vitro studies on H+ secretion, potential difference (PD), short-circuit current (Isc), and resistance across stripped mucosa of frog stomach in Cl-medium have shown that addition of nicotine in the serum bathing fluid caused a marked inhibition of the H+ secretory rate and an increase of PD and Isc without change of the transmucosal resistance. A dose-response correlation was indicated. During the first 8 min, the changes in the measured parameters, namely, PD versus Ih and Isc versus Ih, were linear. After 8 min, a deviation from linearity was observed. From the slope of the regression lines, the resistance of the electrogenic Cl- pump on the mucosal membrane (Rcl) was calculated to be 127 omega cm2 and the resistance of the chloride pathway on the serosal side (Rcl) was 407 omega cm2. The resistance of the H+ pump on the mucosal membrane (Rh) in Cl- medium was estimated to be 385 omega cm2. The sum of the emf's of the Cl+ pump on the mucosal membrane and of the Cl- gradient across the serosal membrane, namely Ecl + Ecl, was found to be 35 mV. The presence of such linear relationships between measured versus the H+ rate and Isc versus Ih lends support to the electrogenic theory of HCl secretion.
Lipoprotein lipase distribution in rat adipose tissues: effect on chylomicron uptake.
Authors: Hartman A D
Published: December 2017

Adipocytes in the epididymal (Epi) and perirenal (PR) depots of the rat increased continuously in size in rats ranging fromm 50 to 550 g body wt. In contrast, cell size in the subcutaneous (SC) and mesenteric (M) depots was similar to that in the other two depots only until rats achieved 250-350 g. Thereafter, adipocytes in the latter depots were significantly smaller than in the former. In all four depots, the activity of lipoprotein lipase (LPL) per 10(6) cells increased with increasing size in both fed and fasted rats. No significant differences were noted in LPL activity per 10(6) cells between depots as a function of cell size in either nutritional state. During growth, a greater percentage of whole tissue LPL of all depots was sequestered within enlarging adipocytes, resulting in an absolute decrease in activity extracellulalrly. This effect was least pronounced in the Epi and PR depots. In large adipocytes of fed rats, decreased extracellular localization of LPL was paralleled in vivo by decreased uptake of chylomicron triglyceride fatty acids in all depots. In fasted rats, uptake was low and unaffected by changes in cell size in all sites.
Biliary transport of cholephilic dyes: evidence for two different pathways.
Authors: Mahu J L , Duvaldestin P , Dhumeaux D , Berthelot P
Published: December 2017

The hepatobiliary transport of three structurally related phthaleins was compared in the rat, and found to differ to a large extent in three experimental conditions: 1) after a 72-h fast; 2) after a 4-day phenobarbital treatment; and 3) during infusion of bile salts: sodium dehydrocholate or taurocholate. In the fasting group, bile flow and bile salt excretion (on a whole liver basis) decreased by 49 and 41%, respectively; bromsulphthalein sodium (BSP) and dibromsulphthalein sodium (DBSP) transport maximum (Tm) were reduced by 59 and 50%; however, rose bengal (RB) Tm remained normal. Phenobarbital pretreatment yielded a 44 and 29% increase in BSP and DBSP Tm, respectively, whereas RB Tm remained unchanged. Dehydrocholate infusion caused a 27 and 49% increase in BSP and DBSP Tm, whereas RB Tm increased by 12%. On the contrary, equimolar taurocholate infusion yielded a more important increase in RB Tm (56%) than in BSP and DBSP (31 and 22% respectively). It is suggested that RB does not share the same liver-to-bile excretory pathway as that of the former molecules. Our results emphasize the difficulties in predicting the biliary excretion of foreign compounds, even when their structure is closely similar.
Unidirectional influx of glutamine and other neutral amino acids into liver of fed and fasted rat in vivo.
Authors: Pardridge W M
Published: December 2017

The fractional extraction of unidirectional influx of several neutral amino acids (glutamine, leucine, alanine, tryptophan, and cycloleucine) into rat liver in vivo is studied with a tissue-sampling, single-injection technique. Liver uptake of 14C-amino acid is expressed as an index relative to the hepatic clearance of a 3H-labeled water (3HOH) internal reference. The maximal fractional extraction of 3HOH influx into liver, 0.85, and the rate constant of 3HOH exodus back to blood, 0.87 min-1, provide an estimate of portal blood flow, 0.93 ml min-1 g-1, in the barbiturate-anesthetized, laparotomized rat. Given the extraction data for the 3HOH reference, liver uptake indices for the five amino acids studied are converted into maximal fractional extractions of amino acid influx into liver: glutamine, 0.72 +/- 0.03; leucine, 0.56 +/- 0.02; alanine, 0.43 +/- 0.04; tryptophan, 0.40 +/- 0.03; cycloleucine, 0.25 +/- 0.01; and sucrose, 0.09 +/- 0.02. The influx of glutamine and cycloleucine is shown to be increased (35%) with 48 h of fasting. These data indicate that glutamine penetrates the liver cell membrane faster than any of the 19 amino acids studied thus far. The rate of unidirectional influx of glutamine and other amino acids into liver is estimated and reveals that the capacity of liver cells to transport amino acids is severalfold greater than that of other organs such as brain or muscle.
Development in calves and heifers after hypophysial stalk transection or hypophysectomy.
Authors: Anderson L L
Published: December 2017

Growth was inhibited markedly in prepuberal bull and heifer calves after either hypophysial stalk transection or hypophysectomy as compared with that found in sham-operated calves or in unoperated calves. Male mounting behavior and evidence of puberal estrous behavior were lost or undetected after hypophysial stalk transection or hypophysectomy. Testes regressed, contained few spermatogonia and interstitial cells, and lacked spermatogenesis. Epithelial cells of seminal vesicles, bulbourethral glands, and prostate were cuboidal, indicating inadequate testicular androgen. Atresia of numerous ovarian follicles and reduced ovarian weight occurred in hypophysectomized heifer calves. Graafian follicles regressed after hypophysial stalk transection of sexually mature heifers, but ovaries responded to pregnant mare serum and human chorionic gonadotropin by follicular development, ovulation, and formation of multiple corpora lutea. Thyroid and adrenal gland weights decreased and adrenal cortices atrophied after hypophysectomy, but not after stalk transection. Thyroid glands contained colloid-filled follicles with flattened epithelial cells; atrophy was more extensive after hypophysectomy. Hypophysial stalk transection or hypophysectomy severely depresses growth and arrests sexual development in young calves, but in mature animals exongenous gonadotropins can sustain gonadal function.
Brain serotonin turnover in chronically uremic rats.
Authors: Siassi F , Wang M , Kopple J D , Swendseid M E
Published: December 2017

Brain serotonin turnover was investigated in chronically uremic and sham-operated pair-fed control rats. Animals were injected ip with 100 mg/kg body wt of pargyline HCl, a nonreversible monoamine oxidase inhibitor, and decapitated 0, 30 and 60 min later. The level of total tryptophan in plasma was decreased, and that of free tryptophan was increased in the uremic group. Uremic and control rats had similar concentrations of tryptophan and serotonin at 0 and 30 min after pargyline administration. However, the brain serotonin concentration was elevated in the uremic group 60 min after pargyline treatment. The brain serotonin turnover rate was higher and serotonin turnover time was lower in the uremic group. These results indicate that uremic stress, in addition to altering plasma tryptophan levels, also affects brain serotonin turnover.
Calcium dependence of neuromuscular events in esophageal smooth muscle of the opossum.
Authors: de Carle D J , Christensen J , Szabo A C , Templeman D C , McKinley D R
Published: December 2017

Intramural nerves in smooth muscle strips from opossum esophagus were stimulated electrically to cause contractions of longitudinal body muscle, off responses of transverse body muscle and relaxations of sphincter muscle. Krebs solution was modified by calcium removal by strontium substitution for calcium, by adding magnesium, and by adding nitroprusside. Longitudinal muscle contractions were abolished by calcium removal and by excess magnesium; they were unaffected by nitroprusside; strontium could not replace calcium. Off responses were abolished by calcium removal and by excess magnesium; they were depressed by nitroprusside; strontium effectively replaced calcium. Resting active tension in sphincter strips was partly reduced by calcium removal and by excess magnesium; it was abolished by nitroprusside; strontium could not replace calcium. Relaxations in sphincter strips were unaffected by all experimental conditions. Longitudinal contractions, off responses, and resting active tension of the sphincter represent different kinds of calcium activation of muscle. The excitatory nerves (which are cholinergic) in longitudinal muscle are calcium dependent, the nerves that produce off responses may not be, and the nerves that relax the sphincter are not.
Activity of chloride in absorptive cells of Amphiuma small intestine.
Authors: White J F
Published: December 2017

Double-barreled chloride-selective microelectrodes constructed by a new method have been used to determine intracellular chloride activity (aic1) in the absorptive cells of isolated, stripped proximal and distal segments of Amphiuma small intestine. Chloride was passively distributed across the mucosal membrane in fall and winter animals and aic1 is about 20 mM. In contrast summer animals actively accumulated chloride in both proximal and distal segments. Parallel measurements of intracellular chloride concentration (Cic1) reveal a very low apparent chloride activity coefficient (aic1/CiC1) indicating that all of the chloride is not free in the cytoplasm. The chloride activity in the bath immediately adjacent to the mucosa is higher than in the bulk solution.
Facilitation of hepatic uptake of phenol 3,6-dibromphthalein disulfonate by taurocholate.
Authors: Marinovic Y , Glasinovic J C , Semelle B , Boivieux J F , Erlinger S
Published: December 2017

The influence of sodium taurocholate (TC) on the hepatic uptake of phenol 3,6-dibromphthalein disulfonate (dibromosulphophthalein, DBSP) was examined in the dog. Single injections of DBSP (7.5-83.3 mg-kg-1) were given intravenously and the initial velocity of uptake (V) of the dye was calculated from the plasma disappearance rate measured during the 1st 5 min. It was observed that: a) the initial velocity of uptake of DBSP increased with the dose (D) in a nonlinear way, a finding consistent with Michaelis-Menten kinetics; the maximal initial velocity of uptake (Vmax) was 7.5+/-1.0 (SD) mg-min-1-kg body wt-1, and the half-saturation constant (Kd) was 27.7+/-7.0 (SD) mg-kg-1; b) when a TC infusion was given prior to the DBSP injection, the initial disappearance of the dye was more rapid than in the absence of the bile acid; Vmax increased to 12.3+/-2.0 (SD) mg-min-1-kg-1 (P less than 0.001) and Kd increased to 50.3+/-12.8 (SD) mg-kg-1 (P less than 0.001). These results indicate that: 1) the uptake of DBSP by the liver cell is a saturable process; 2) TC increases both the Vmax, suggesting a facilitation of the uptake process, and the Kd, suggesting competition for a common site. This effect of TC on DBSP uptake is similar to the previously described effect of this bile salt on BSP excretion into bile and suggests an interaction of bile salts with the uptake process of dyes.
A comparison of intrinsic nerve supplies of two muscular layers of duodenum.
Authors: Anuras S , Christensen J , Cooke A R
Published: December 2017

The duodenums of opossums and cats were cut into strips 2 mm wide and 2-2.5 cm long. Strips cut in the direction of the oral-caudal axis were called longitudinal strips, and those cut at 90 degrees to that axis were called circular strips. Each muscle strip was stimulated with trains of electrical rectangular pulses (10 Hz, 50-70 V, 0.5 ms). In the longitudinal strips, electrical field stimulation caused contraction, and this contraction was abolished by atropine, 10(-7) M. In the circular strips, electrical field stimulation caused relaxation. This relaxation was abolished by tetrodotoxin, 10(-7) M, but it was not affected by antagonists to adrenergic and cholinergic transmission, nor by some gastrointestinal hormones. Reserpinization of the opossums or alteration of the frequencies of electrical field stimulation from 0.1-50 Hz did not affect or alter the relaxation of the circular strips or the contraction of the longitudinal strips. These findings suggest that the longitudinal muscle is dominated by an excitatory cholinergic innervation, and the circular muscle is dominated by a nonadrenergic, noncholinergic inhibitory innervation.
Episodic secretion of arginine vasopressin.
Authors: Weitzman R E , Fisher D A , DiStefano J J , Bennett C M
Published: December 2017

The plasma arginine vasopressin (pAVP) response to osmotic stimulation was studied in dogs and sheep by sampling at frequent intervals during steady-state dehydration and during water diuresis. Frequent sampling also was conducted after continuous infusion or bolus injection of 5 or 20 g/100 ml NaCl. A pulsatile pattern of pAVP was observed after such infusions or injections and in some animals after water deprivation. This pattern was not seen after water loading or in mildly dehydrated animals. The short term changes in pAVP during continuous infusion of 5 g/100 ml NaCl could not be correlated with variations in plasma tonicity. Rather, they appeared to reflect discontinuous hypothalamic posterior pituitary release of AVP. Thirst was evoked by a lower dose of 5 g/100 ml NaCl than was required for consistent stimulation of pAVP release, and the thirst response frequently was observed prior to the peak AVP response after bolus injection of 5 and 20 g/100 ml NaCl.
Transport of purine nucleotides and nucleosides by in vitro rabbit ileum.
Authors: Harms V , Stirling C E
Published: December 2017

The kinetics of [14C]ATP and [14C]adenosine entry into rabbit ileum were measured using 1-min mucosal exposures. ATP influx was the sum of a linear (P = 1.02 X 10(-3) cm/min) and nonlinear component (Jm = 4.07 nmol/min cm2, Km = 0.31 mM). Adenosine yielded quantitatively similar results. The kinetics of [gamma-32P]ATP entry were only linear (P = 0.55 X 10(-3) cm/min). These data indicate that at least 85% of the terminal phosphate of ATP is hydrolyzed during transport. Inhibitory measurements indicate that ring-labeled ATP and adenosine compete for a common entry path; however, adenosine does not inhibit the saturable component of [14C]ATP to the degree expected of a simple carrier-mediated system. Adenosine (5 mM) produced no inhibition of [gamma-32P]ATP (0.1-1.0 mM) entry. Measurement of hydrolysis during incubation indicates a negligible fraction of uptake results from labeled adenosine released into the bulk solution. Hydrolysis of ATP followed by a preferred uptake of the adenosine released at the membrane surface probably accounts for most of the observed transport. [14C]ATP entry depended neither on [Na+], [Mg2+], nor [Ca2+] of the bulk solution. Structural requirements for the saturable pathway were also investigated. Autoradiography of [3H]ATP confirmed that the labeled material entered the epithelial cells and that uptake was nonuniform among cells.
Glucose utilization and role of blood in endotoxin shock.
Authors: Hinshaw L B , Archer L T , Beller B K , White G L , Schroeder T M , Holmes D D
Published: December 2017

The present study was conducted to explore influences modifying glucose uptake in canine blood administered LD100 E. coli endotoxin. Particular emphasis was given to assay the role of the white blood cell (WBC) in glucose utilization. Significant increases in glucose uptake and lactic acid production, attributed to increased activity of the WBC, were observed 1-3 h after endotoxin was added to blood in vitro. Although a net increase in glucose utilization was noted, endotoxin simultaneously exerted adverse effects by depressing glucose uptake below predicted values (Q10 = 2.12 with LD100 endotoxin vs. 2.78 in saline controls) and increasing WBC mortality rate. Blood from dogs pretreated with sublethal doses of endotoxin in vivo utilized glucose at an accelerated rate when subjected to endotoxin in vitro. Excess glucose was consumed because of elevated numbers of white blood cells although additional glucose requirements after endotoxin were independent of temperature between the ranges of 34-41 degrees C. All animals pretreated with daily sublethal injections of endotoxin for 3 days survived superlethal doses of endotoxin.
Effect of thyroparathyroidectomy of calcium metabolism in rats: role of 1,25-dihydroxyvitamin D3.
Authors: Rizzoli R , Fleisch H , Bonjour J P
Published: December 2017

Thyroparathyroidectomy (TPTX) decreases plasma calcium, bone formation and resorption, and tubular reabsorption of calcium. It also reduces the production of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] which very likely results in the decrease in the intestinal calcium absorption (Vna) observed after TPTX. We have examined whether the influence of TPTX on plasma calcium and bone calcium fluxes could be corrected by doses of 1,25-(OH)2D3 (2 X 13 pmol/day ip), which just normalize Vna. The study was made by calcium balance and 45Ca kinetics in rats receiving a normal supply of vitamin D3. The results show that in TPTX rats physiological doses of 1,25-(OH)2D3 increased plasma calcium and decreased plasma phosphate. Calcium retention was not fully corrected because 1,25-(OH)2D3 increased urinary calcium excretion. The deposition into and the release of calcium from bone were enhanced by 1,25-(OH)2D3 but remained lower than in pair-fed sham-operated animals. Thus, in as much as the diminished renal production of 1,25-(OH)2D3 in TPTX is entirely responsible for the reduced Vna, the decrease in 1,25-(OH)2D3 could only partly explain the effect of thyroparathyroidectomy on bone calcium fluxes.