bluuebunny/crossref_metadata_2025 huggingface dataset:
Vasopressin-inducible ubiquitin-specific protease 10 increases ENaC cell surface expression by deubiquitylating and stabilizing sorting nexin 3
Authors: Boulkroun Sheerazed , Ruffieux-Daidié Dorothée , Vitagliano Jean-Jacques , Poirot Olivier , Charles Roch-Philippe , Lagnaz Dagmara , Firsov Dmitri , Kellenberger Stephan , Staub Olivier
Published: July 2008

Adjustment of Na+balance in extracellular fluids is achieved by regulated Na+transport involving the amiloride-sensitive epithelial Na+channel (ENaC) in the distal nephron. In this context, ENaC is controlled by a number of hormones, including vasopressin, which promotes rapid translocation of water and Na+channels to the plasma membrane and long-term effects on transcription of vasopressin-induced and -reduced transcripts. We have identified a mRNA encoding the deubiquitylating enzyme ubiquitin-specific protease 10 (Usp10), whose expression is increased by vasopressin at both the mRNA and the protein level. Coexpression of Usp10 in ENaC-transfected HEK-293 cells causes a more than fivefold increase in amiloride-sensitive Na+currents, as measured by whole cell patch clamping. This is accompanied by a three- to fourfold increase in surface expression of α- and γ-ENaC, as shown by cell surface biotinylation experiments. Although ENaC is well known to be regulated by its direct ubiquitylation, Usp10 does not affect the ubiquitylation level of ENaC, suggesting an indirect effect. A two-hybrid screen identified sorting nexin 3 (SNX3) as a novel substrate of Usp10. We show that it is a ubiquitylated protein that is degraded by the proteasome; interaction with Usp10 leads to its deubiquitylation and stabilization. When coexpressed with ENaC, SNX3 increases the channel's cell surface expression, similarly to Usp10. In mCCDcl1cells, vasopressin increases SNX3 protein but not mRNA, supporting the idea that the vasopressin-induced Usp10 deubiquitylates and stabilizes endogenous SNX3 and consequently promotes cell surface expression of ENaC.
Increased dietary NaCl induces renal medullary PGE2production and natriuresis via the EP2 receptor
Authors: Chen Jian , Zhao Min , He Wenjuan , Milne Ginger L. , Howard Jocelyn R. H. , Morrow Jason , Hébert Richard L. , Breyer Richard M. , Chen Jing , Hao Chuan-Ming
Published: July 2008

A high-NaCl diet induces renal medullary cyclooxygenase (COX)2 expression, and selective intramedullary infusion of a COX2 inhibitor increases blood pressure in rats on a high-salt diet. The present study characterized the specific prostanoid contributing to the antihypertensive effect of COX2. C57BL/6J mice placed on a high-NaCl diet exhibited increased medullary COX2 and microsomal prostaglandin E synthase1 (mPGES1) expression as determined by immunoblot and real-time PCR. Cytosolic prostaglandin E synthase and prostacyclin synthase were not induced by the high-salt diet. Immunofluorescence showed mPGES1 in collecting ducts and interstitial cells. High salt increased renal medullary PGE2as determined by gas chromatography/negative ion chemical ionization mass spectrometry. The effect of direct intramedullary PGE2infusion was examined in anesthetized uninephrectomized mice. Intramedullary PGE2infusion (10 ng/h) increased urine volume (from 3.3 ± 0.6 to 9.5 ± 1.6 μl/min) and urine sodium excretion (0.11 ± 0.02 to 0.32 ± 0.05 μeq/min). To determine which E-prostanoid (EP) receptor(s) mediated PGE2- dependent natriuresis, EP-selective prostanoids were infused. The EP2agonist butaprost produced natriuresis (from 0.06 ± 0.02 to 0.32 ± 0.05 μeq/min). The natriuretic effect of intramedullary PGE2or butaprost was abolished in EP2-deficient mice, which exhibit NaCl-dependent hypertension. In conclusion, a high-salt diet increases renal medullary COX2 and mPGES1 expression, and increases renal medullary PGE2synthesis. Renal medullary PGE2promotes renal sodium excretion via the EP2 receptor, thereby maintaining normotension in the setting of high salt intake.
Heme oxygenase induction attenuates afferent arteriolar autoregulatory responses
Authors: Botros Fady T. , Prieto-Carrasquero Minolfa C. , Martin Victoria L. , Navar L. Gabriel
Published: July 2008

Heme oxygenases (HO-1, HO-2) catalyze conversion of heme to iron, carbon monoxide (CO), and biliverdin/bilirubin. We studied the effects of renal HO-1 induction on afferent arteriole (Aff-Art) autoregulatory responses to increases in renal perfusion pressure (RPP). Rats were treated with hemin and SnCl2to induce HO-1, and Aff-Art autoregulatory responses were evaluated using the rat blood-perfused juxtamedullary nephron preparation. Renal HO-1 expression was significantly increased in hemin- and SnCl2-treated rats, while HO-2 was not altered. Aff-Art autoregulatory constrictor responses to increases in RPP from 100 to 150 mmHg were attenuated in hemin- and SnCl2-treated rats compared with control rats (+1.1 ± 3.3, n = 9 and +4.4 ± 5.3, n = 9 vs. −14.2 ± 1.5%, n = 10, respectively) ( P < 0.05). Acute HO inhibition with chromium mesoporphyrin (CrMP; 15 μmol/l) restored Aff-Art autoregulatory responses in hemin- and SnCl2-treated rats. Superfusing Aff-Arts from control rats with 100 μmol/l biliverdin did not alter autoregulatory responses; however, superfusion with 1 mmol/l CO significantly attenuated autoregulatory responses to increases in RPP from 100 to 150 mmHg (+3.3 ± 5.4 vs. −16.6 ± 3.8%, n = 6) ( P < 0.05). Acute soluble guanylate cyclase inhibition with 10 μmol/l ODQ restored Aff-Art autoregulatory responses in hemin-treated rats. Immunohistochemistry shows HO-2 to be expressed mainly in epithelial cells with weak staining in proximal tubules, interlobular arteries, and Aff-Arts. In hemin- and SnCl2-treated rats, HO-1 was induced in tubular epithelial cells but not interlobular arteries and Aff-Arts. We conclude that induction of renal HO-1 attenuates Aff-Art constrictor responses to increases in RPP via increasing CO production from tubular epithelial cells, suggesting that an augmented HO system in pathophysiological conditions modulates renal autoregulation.
GFP-expressing locus ceruleus neurons from Prp57 transgenic mice exhibit CO2/H+ responses in primary cell culture
Authors: Johnson Shereé M. , Haxhiu Musa A. , Richerson George B.
Published: July 2008

The locus ceruleus (LC) contains neurons that increase their firing rate (FR) in vitro when exposed to elevated CO2/H+ and have been proposed to influence the respiratory network to make compensatory adjustments in ventilation. Prp57 transgenic mice express green fluorescent protein (GFP) in the LC and were used to isolate, culture, and target LC neurons for electrophysiological recording. We hypothesized that GFP-LC neurons would exhibit CO2/H+ chemosensitivity under primary culture conditions, evidenced as a change in FR. This is the first study to quantify CO2/H+ responses in LC neuron FR in cell culture. Neurons were continuously bathed with solutions containing antagonists of glutamate and GABA receptors, and the acid-base status was changed from control (5% CO2; pH ∼7.4) to hypercapnic acidosis (9% CO2; pH ∼7.2) and hypocapnic alkalosis (3% CO2; pH ∼7.6). FR was quantified during perforated patch current clamp recordings. Approximately 86% of GFP-LC neurons were stimulated, and ∼14% were insensitive to changes in CO2/H+. The magnitude of the response of these neurons depended on the baseline FR, ranging from 155.9 ± 6% when FR started at 2.95 ± 0.49 Hz to 381 ± 55.6% when FR started at 1.32 ± 0.31 Hz. These results demonstrate that cultured LC neurons from Prp57 transgenic mice retain functional sensing molecules necessary for CO2/H+ responses. Prp57 transgenic mice will serve as a valuable model to delineate mechanisms involved in CO2/H+ responsiveness in catecholaminergic neurons.
Limb venous tone and responsiveness in hypertensive humans
Authors: Delaney Erin P. , Young Colin N. , DiSabatino Angela , Stillabower Michael E. , Farquhar William B.
Published: July 2008

Hypertensive (HTN) animal models demonstrate lower venous compliance as well as increased venous tone and responsiveness compared with normotensive (NTN) controls. However, the extent to which findings in experimental animals can be extended to humans is unknown. Forearm and calf venous compliance were quantified in 9 NTN (23 ± 1 yr) and 9 HTN (24 ± 1 yr) men at baseline, after administration of nitroglycerin (NTG), during a cold pressor test (CP), and post-handgrip exercise ischemia (PEI). Individual pressure-volume relationships from a cuff deflation protocol (1 mmHg/s) were modeled with a quadratic regression. Regression parameters β1 and β2 were used to calculate compliance. A one-way ANOVA was used to compare the beta parameters and a repeated-measures ANOVA was used to compare volumes across all pressures (between groups at baseline and within groups during perturbations). Limb venous compliance was similar between groups (forearm: NTN β1 = 0.11 ± 0.01 and β2 = −0.00097 ± 0.0001, HTN β1 = 0.10 ± 0.01 and β2 = −0.00088 ± 0.0001; calf: NTN β1 = 0.12 ± 0.01 and β2 = −0.00102 ± 0.0001, HTN β1 = 0.11 ± 0.01 and β2 = −0.00090 ± 0.0001). However, at baseline, volume across all pressures (i.e., capacitance) was lower in the forearm ( P ≤ 0.01) and tended to be lower in the calf ( P = 0.08) in HTN subjects. Venous compliance was not altered by any perturbation in either group. Forearm volume was increased during NTG in HTN subjects only. While venous compliance was similar between NTN and HTN adults, HTN adults have lower forearm venous capacitance (volume) which is increased with NTG. These data suggest that young HTN adults may have augmented venous smooth muscle tone compared with NTN controls.
TNF promoter polymorphisms associated with muscle phenotypes in humans
Authors: Liu Dongmei , Metter E. Jeffrey , Ferrucci Luigi , Roth Stephen M.
Published: July 2008

Tumor necrosis factor-α (TNF-α) is a potent catabolic factor to skeletal muscle. Single-nucleotide polymorphisms (SNPs) in the promoter region of the TNF-α coding gene, TNF, have been implicated in the interindividual variation in TNF-α production via transcriptional regulation. The present study investigated the association of muscle phenotypes with five TNF promoter SNPs, which potentially have biological significance. Female and male volunteers ( n = 1,050) from the Baltimore Longitudinal Study of Aging were genotyped, and their regional and total body muscle mass, and arm and leg muscle strength were measured. Results indicated that putative high-expression alleles at positions −1031 and −863, individually or in combination in the haplotype 1031C-863A-857C-308G-238G, were associated with lower muscle mass in men. Specifically, carriers of −1031C, compared with noncarriers, exhibited lower arm muscle mass (6.4 ± 0.1 vs. 6.8 ± 0.1 kg, P = 0.01) and appendicular skeletal muscle mass (ASM) (24.3 ± 0.4 vs. 25.4 ± 0.2 kg, P = 0.02), with leg muscle mass and the ASM index (ASMI; kg/m2) also tending to be lower ( P = 0.06 and 0.07). Similarly, −863A allele carriers (linked with −1031), compared with noncarriers, exhibited lower arm muscle mass (6.4 ± 0.1 vs. 6.8 ± 0.1 kg, P = 0.04). Carriers of the haplotype 1031C-863A-857C-308G-238G, compared with noncarriers, exhibited lower arm muscle mass (6.3 ± 0.2 vs. 6.8 ± 0.1 kg, P < 0.01), trunk muscle mass (25.7 ± 0.5 vs. 26.9 ± 0.3 kg, P < 0.05), and ASM (24.1 ± 0.5 vs. 25.3 ± 0.2 kg, P < 0.025), with tendencies for lower leg muscle mass and ASMI ( P = 0.07 and 0.08). Results indicate that genetic variation in the TNF locus may contribute to the interindividual variation in muscle phenotypes in men.
A Novel Type of Auditory Responses: Temporal Dynamics of 40-Hz Steady-State Responses Induced by Changes in Sound Localization
Authors: Ross Bernhard
Published: July 2008

Magnetoencephalographic responses to 40-Hz amplitude-modulated tones of 4-s duration were recorded in young, middle-aged, and older healthy participants. Interaural phase difference (IPD) in the sound carrier was changed during stimulus presentation from 0 to 180°, resulting in perceptual change from focal to spacious sound. The stimulus modulation elicited synchronized gamma-band oscillations, the 40-Hz auditory steady-state response (ASSR). Equivalent current dipoles were localized in primary auditory cortices. Waveforms of cortical activity showed a decrement in ASSR amplitude 100 ms after stimulus IPD change and modification of ASSR phase, which was maximally 90°, corresponding to 6-ms delay. Time courses of ASSR phase deviation constituted a novel auditory response. The amount of ASSR phase change decreased with increasing stimulus frequency and revealed upper limits for physiological IPD detection. Thresholds for IPD detection were found close to 1,500 Hz in the young, around 1,250 Hz in the middle-aged group, and around 1,000 Hz in the older group. Whereas the ASSR change response revealed aging-related decline of binaural hearing, the amplitude of 40-Hz response and the size of the ASSR change response were not affected by aging. Additional ASSR change responses were recorded at a high rate of stimulus changes every 400 ms. ASSR response detection at this rate was superior to response detection based on the auditory-evoked P1–N1–P2 response. Responses to changes from focal to spacious sound were larger than those in the reverse direction. The ASSRs were interpreted in relation to oscillatory gamma-band activity representing auditory object representation.
Detecting Synfire Chain Activity Using Massively Parallel Spike Train Recording
Authors: Schrader Sven , Grün Sonja , Diesmann Markus , Gerstein George L.
Published: July 2008

The synfire chain model has been proposed as the substrate that underlies computational processes in the brain and has received extensive theoretical study. In this model cortical tissue is composed of a superposition of feedforward subnetworks (chains) each capable of transmitting packets of synchronized spikes with high reliability. Computations are then carried out by interactions of these chains. Experimental evidence for synfire chains has so far been limited to inference from detection of a few repeating spatiotemporal neuronal firing patterns in multiple single-unit recordings. Demonstration that such patterns actually come from synfire activity would require finding a meta organization among many detected patterns, as yet an untried approach. In contrast we present here a new method that directly visualizes the repetitive occurrence of synfire activity even in very large data sets of multiple single-unit recordings. We achieve reliability and sensitivity by appropriately averaging over neuron space (identities) and time. We test the method with data from a large-scale balanced recurrent network simulation containing 50 randomly activated synfire chains. The sensitivity is high enough to detect synfire chain activity in simultaneous single-unit recordings of 100 to 200 neurons from such data, enabling application to experimental data in the near future.
Control of Neuronal Persistent Activity by Voltage-Dependent Dendritic Properties
Authors: Idoux Erwin , Eugène Daniel , Chambaz Antoine , Magnani Christophe , White John A. , Moore Lee E.
Published: July 2008

Neural integrators and working memory rely on persistent activity, a widespread neural phenomenon potentially involving persistent sodium conductances. Using a unique combination of voltage-clamp, dynamic-clamp, and frequency-domain techniques, we have investigated the role of voltage-dependent conductances on the dendritic electrotonic structure of neurons of the prepositus hypoglossi nucleus (PHN), which is known to be involved in oculomotor integration. The PHN contains two main neuronal populations: type B neurons with a double afterhyperpolarization and type D neurons, which not only are oscillatory but also have a greater electrotonic length than that of type B neurons. The persistent sodium conductance is present in all PHN neurons, although its effect on the dynamic electrotonic structure is shown to significantly differ in the two major cell types present in the nucleus. The electrotonic differences are such that the persistent sodium conductance can be almost perfectly manipulated in a type B neuron using an on-line dynamic clamp to add or subtract virtual sodium ion channels. The dynamic-clamp results are confirmed by data-fitted models, which suggest that the persistent sodium conductance has two different roles depending on its somatic versus dendritic location: perisomatic conductances could play a major role in maintaining action potential discharge and dendritic conductances would be more involved in other computational properties, such as those involving remote synaptic processing or bistable events.
Dynamic Coding of Vertical Facilitated Vergence by Premotor Saccadic Burst Neurons
Authors: Van Horn Marion R. , Cullen Kathleen E.
Published: July 2008

To redirect our gaze in three-dimensional space we frequently combine saccades and vergence. These eye movements, known as disconjugate saccades, are characterized by eyes rotating by different amounts, with markedly different dynamics, and occur whenever gaze is shifted between near and far objects. How the brain ensures the precise control of binocular positioning remains controversial. It has been proposed that the traditionally assumed “conjugate” saccadic premotor pathway does not encode conjugate commands but rather encodes monocular commands for the right or left eye during saccades. Here, we directly test this proposal by recording from the premotor neurons of the horizontal saccade generator during a dissociation task that required a vergence but no horizontal conjugate saccadic command. Specifically, saccadic burst neurons (SBNs) in the paramedian pontine reticular formation were recorded while rhesus monkeys made vertical saccades made between near and far targets. During this task, we first show that peak vergence velocities were enhanced to saccade-like speeds (e.g., >150 vs. <100°/s during saccade-free movements for comparable changes in vergence angle). We then quantified the discharge dynamics of SBNs during these movements and found that the majority of the neurons preferentially encode the velocity of the ipsilateral eye. Notably, a given neuron typically encoded the movement of the same eye during horizontal saccades that were made in depth. Taken together, our findings demonstrate that the brain stem saccadic burst generator encodes integrated conjugate and vergence commands, thus providing strong evidence for the proposal that the classic saccadic premotor pathway controls gaze in three-dimensional space.
Effect of Synaptic Connectivity on Long-Range Synchronization of Fast Cortical Oscillations
Authors: Bazhenov M. , Rulkov N. F. , Timofeev I.
Published: July 2008

Cortical gamma oscillations in the 20- to 80-Hz range are associated with attentiveness and sensory perception and have strong connections to both cognitive processing and temporal binding of sensory stimuli. These gamma oscillations become synchronized within a few milliseconds over distances spanning a few millimeters in spite of synaptic delays. In this study using in vivo recordings and large-scale cortical network models, we reveal a critical role played by the network geometry in achieving precise long-range synchronization in the gamma frequency band. Our results indicate that the presence of many independent synaptic pathways in a two-dimensional network facilitate precise phase synchronization of fast gamma band oscillations with nearly zero phase delays between remote network sites. These findings predict a common mechanism of precise oscillatory synchronization in neuronal networks.
Compact Bandstop Filters with Extended Upper Passbands
Authors: Alkanhal Majeed A. S.
Published: July 2008

This paper presents new compact bandstop filters (BSFs) with extended upper passbands. In the basic proposed filter configuration, the conventional quarter-wavelength open-stub resonators are replaced with equivalent two-section stepped impedance resonators. Transmission line analysis is used to determine the dimensions of the equivalent stepped impedance sections. The filter structure is analyzed using a full wave electromagnetic (EM) simulator and then realized at 2.3 GHz band. Experiments have also been done to validate the performance of the design concept. Compared with the conventional quarter-wavelength-based bandstop filter, significant extensions of the upper passband beyond 9 GHz and 40% size reduction are achieved. Two other variations of the proposed basic BSF with further size reduction (more than 60%) are implemented and their measured performances are verified.
On-Chip Bondwire Magnetics with Ferrite-Epoxy Glob Coating for Power Systems on Chip
Authors: Lu Jian , Jia Hongwei , Arias Andres , Gong Xun , Shen Z. John
Published: July 2008

A novel concept of on-chip bondwire inductors and transformers with ferrite epoxy glob coating is proposed to offer a cost effective approach realizing power systems on chip (SOC). We have investigated the concept both experimentally and with finite element modeling. A Q factor of 30–40 is experimentally demonstrated for the bondwire inductors which represents an improvement by a factor of 3–30 over the state-of-the-art MEMS micromachined inductors. Transformer parameters including self- and mutual inductance and coupling factors are extracted from both modeled and measured S-parameters. More importantly, the bondwire magnetic components can be easily integrated into SOC manufacturing processes with minimal changes and open enormous possibilities for realizing cost-effective, high-current, high-efficiency power SOCs.
Distribution of Parasympathetic Motoneurones in the Oculomotor Complex Innervating the Ciliary Ganglion in the Marmoset (Callithrix jacchus)
Authors: Clarke R.J. , Coimbra C.J.P. , Aléssio M.L.
Published: July 2008

Parasympathetic motoneurones in the oculomotor complex which innervate the ciliary ganglion were identified using the horseradish peroxidase (HRP) retrograde axonal tracer technique. The ciliary ganglion was located behind the eye by a lateral orbital approach and injected with HRP pellets mounted on the tips of microelectrodes. Most of the labelled cells were distributed throughout the whole Edinger-Westphal nucleus (EW). Outside the EW, only a small number of labelled cells were found, and most of these were located in the median zone ventral to the EW. There was no evidence of a division of the EW into rostral and posterior subnuclei, nor for separate cell populations in the EW and the anterior median nucleus (AM), respectively. At rostral levels labelled cells were confined to the EW with no overlap into the AM. In contrast to most previous studies no labelled cells were found in the AM. The possible physiological functions of the EW and the ventral components of the EW are discussed.
Testicular Organogenesis in the Fetal Calf: Interstitial Endocrine (Leydig) Cell Development
Authors: Hullinger R.L. , Wensing C.J.G.
Published: July 2008

The development of the interstitial endocrine (Ledig) cells of the fetal testis in the calf is described and correlated with a swelling reaction of the gubernaculum and normal, prenatal descent of the testis. An hydroxy-steroid dehydrogenase (HSD) procedure is used to determine the onset of functional activity for the interstitial endocrine cells (IEC). The NADH control procedure was strongly positive for the IECs at all ages investigated, indicating that these cells utilize the pyridine nucleotide as a coenzyme for oxireduction conversions. The 3α- and 3β-HSD reactions were strongly positive and lightly positive, respectively, demonstrating that these cells contain the HSDs commonly utilized in the early steroidogenesis. TEM revealed structural evidence of this differentiating steroidogenic capability within IECs. During the period of the swelling reaction there is a functional IEC population, but there is no evidence presented by this study for a causal relationship of the gubernacular swelling reaction and subsequent normal descent of the testis into the scrotum.
Macrophages in Pacinian Corpuscles
Authors: Ide Chizuka , Tohyama Koujiro
Published: July 2008

The presence of macrophages in the outer bulb region of mouse, monkey and human Pacinian corpuscles was demonstrated by light and electron microscopy. In the normal, nontreated, Pacinian corpuscles, a few particular cells were located in the spaces between lamellae of the outer bulb. These cells contained numerous vesicles and vacuoles, and various cytoplasmic processes. When horseradish peroxidase (HRP) was injected locally or systemically, many HRP-positive cells, which were considered to be similar to the particular cells described above, were found in the outer bulb region of the corpuscles. Electron microscopy revealed that these cells contained HRP in vesicles and vacuoles, suggesting that they were macrophages vigorously taking up exogenous HRP. Macrophages in the Pacinian corpuscles are considered to work as scavengers to keep the inner environment of the corpuscles clear and constant with regard to its macromolecular content.
Stimulating Effect of Natural Estrogens on Proliferation of Hepatocytes in Adult Mice
Authors: Fujii H. , Hayama T. , Kotani M.
Published: July 2008

A single oral administration of natural principal estrogens, estrone (Ei), 17β-estradiol (E2) and estriol (E3), caused active proliferation of hepatocytes of adult mouse liver. Steroid hormones tested (testosterone, progesterone and cortisone) other than estrogens were not stimulants of proliferation of hepatocytes. Among these three natural estrogens, E3 was found to be the most potent stimulant of hepatocyte proliferation and E, was the weakest. The possible mechanism of the hepatocyte-proliferating potency of estrogens was discussed in close relationship to their stimulating effect on the reticuloendothelial system.
Iron-Containing Granules in the Syncytiotrophoblast of the Human Chorionic Villi
Authors: Hamasaki K. , Fujimoto S. , Yamamoto K. , Okamura Y.
Published: July 2008

The syncytiotrophoblast of the human chorionic villi during earlier stages of gestation contains abundant granules derived from Golgi complexes. The granules often include very electron-dense lamellae in their interior, and X-ray microanalysis revealed the presence of iron in these lamellae. It is, therefore, supposed that iron particles absorbed into the syncytiotrophoblast are transported to Golgi complexes and integrated into these lamellae. No evidences that the granules are released from the.cells by exocytosis have been proved. Thus, one possibility to their nature might be considered, that is they play a role in lysosomal storage of iron during earlier stages when the capillaries in the chorionic stroma are undeveloped and so have little ability to transport iron into the fetal circulation.
Ultracytochemical Nuclear Calcium Distribution in Pancreatic B Cells: Its Relation to Glucose-Stimulated Insulin Secretion
Authors: Semino María C. , Gómez Dumm César L.A. , Rebolledo Oscar R. , Hernández Rodolfo E. , Gagliardino Juan J.
Published: July 2008

Calcium distribution in pancreatic B cells was studied, with the aid of the pyroantimonate technique, at different times of glucose-induced secretory activity in the perfused rat pancreas. Specificity of the pyroantimonate precipitates for calcium was assessed by EGTA cross-incubation. Quantitative studies for these calcium pyroantimonate precipitates were performed by a morphometrictechnique. Pyroantimonate precipitates within the B cell show both time and glucose dependence. At any time-point studied, in the nucleus as well as in other organelles, they were more numerous when glucose was increased in the medium from 3.3 to 16.6 mmol/l. The total number of nuclear calcium pyroantimonate precipitates rose sharply at the time corresponding to the refractory period, falling after that to almost the number found at the prestimulatory period. Otherwise, glucose significantly modifies the temporal distribution of precipitates bound to euchromatin, heterochromatin and perichromatin. These changes in nuclear calcium pyroantimonate precipitates during different periods of B cell secretory activity may indicate an active role of the cation in some nuclear regulatory function during glucose-induced release of insulin.
The Hedgehog Uterus
Authors: Lescoat Denise , Saboureau Michel , Castaing Laurent , Chambon Yves
Published: July 2008

The ultrastructure of the luminal epithelium of the hedgehog uterus is described on the basis of material taken from 11 animals in three different hormonal situations: castrated, active and hibernating animals. The whole uterine epithelium is composed of microvillous cells. Its appearance is very similar in ovariectomized and hibernating animals. It differs from that observed in active animals where the epithelium is taller, microvilli are more numerous and longer, and where nuclei and cytoplasm display a very active ultrastructural appearance. The results now available indicate that ultrastructural changes occurring within the cells are certainly correlated with plasma sex steroid hormone concentrations. The present paper also reports the regular occurrence of nuclear bodies in uterine cells.
Effects of Maternal Administration of Diethylstilbestrol and Estradiol on the Newborn Guinea Pig
Authors: Davies I. , Russell Marcia , Davenport G.R.
Published: July 2008

The subcutaneous injection of diethylstilbestrol (2.5 µg/day) into pregnant guinea pigs from the 28th or 40th day to term resulted in an accelerated tempo of differentiation of the genital tract of the female offspring at birth, as well as intense estrogenic stimulation. Estradiol (50 µg per day) injected over the same period caused insignificant estrogenic stimulation in the newborn. The normal embryogenesis of the genital tract is described and a pattern of caudocranial differentiation identified. The normal genital tract is described as a basis for the analysis of results in the newborn. Comparative studies in other animals are discussed.
The Effects of Simulated Increases in Body Weight on the Developing Rat Tibia: A Histologic Study
Authors: Simon Mark R. , Holmes Kenneth R.
Published: July 2008

Groups of weanling and newborn Sprague-Dawley rats were each subjected to a specific 10% simulated increase in body weight to a maximum of a doubling of body weight, using constant centrifugation, to study the effects of quantified, increased, intermittent, compressive forces on the histomorphology of the proximal tibial epiphysial growth plate. The weanling rats were sacrificed after 30 and 60 days of centrifugation; the newborn rats were sacrificed after 90 days of centrifugation. The results demonstrated no prominent changes in histomorphology, when compared to the controls, in the weanling rats sacrificed at 30 days of centrifugation, or in newborn rats subjected to 90 days of centrifugation; however, a prominent thinning of the growth plates was observed in the weanling rats sacrificed at 60 days of centrifugation.
Localization and Morphometric Analysis of Masticatory Muscle Afferent Neurons in the Nucleus of the Mesencephalic Root of the Trigeminal Nerve in the Cat
Authors: Capra Norman F. , Anderson Kenneth V. , Atkinson, III. Ralph C.
Published: July 2008

Injections of horseradish peroxidase (HRP) were made into the ipsilateral temporal muscle and contralateral masseter muscle of 10 cats in order to identify and characterize neurons in the nucleus of the mesencephahc root of the trigeminal nerve that innervate muscle receptors in the orofacial periphery. Neurons labelled by HRP injections and unlabelled cells from 5 control cats were measured with a computer-based image analyzer, and their position was mapped on a stereotaxic graph. Cells that innervate the masseter and temporal muscles were identified throughout the rostrocaudal extent of the nucleus. There was no indication of a somatotopic pattern nor of a specific segregation within the nucleus for cells innervating muscle receptors. The nucleus contained small, rounded unipolar neurons located primarily in the dorsal border of the periaqueductal gray (PAG) matter in the rostral part of the nucleus and larger oval unipolar neurons which were scattered throughout the nucleus, but were predominant in the pontine portion of the nucleus. HRP injections labelled both large and small cells, as well as occasional multipolar cells. The last-mentioned tended to be located in the lateral margins of the PAG. The mean geometric values obtained for the control group were: area 552.7 μm2 perimeter 110.3 μm; maximum diameter 36.0 μm. and diameter of an equivalent circle 26.1 μm. The mean values of the labelled neurons were: area 606.6 μm2; perimeter 100.1 μm; maximum diameter 36.0 μm, and diameter of an equivalent circle 27.2 μm.
Vascular Perfusability and Capillary Macromolecular Permeability in the Mechanically Induced Rabbit Hydrosalpinx
Authors: Verco Christopher J. , Gannon Brendan J.
Published: July 2008

The mechanically induced rabbit hydrosalpinx, a frequently studied animal model of human hydrosalpinges, was examined to determine the variations, in vascular perfusion and capillary albumin permeability, which occur in hydrosalpinges. At laparotomy, 4 adult female virgin rabbits underwent isthmic and ampullary occlusion with small tantalum clips. 4 weeks later, fluorescein isothiocyanate-labelled bovine serum albumin (FITC BSA: molecular weight 67,000) was injected intravenously 5 min before oviduct excision. Examination of tubal sections by incident light fluorescent microscopy demonstrated poor interplical vascular perfusabüity and markedly reduced interplical capillary permeability to FITC BSA in both isthmic and ampullary segments of hydrosalpinx. These observations imply that, in the experimental rabbit hydrosalpinx, interplical deciliation is probably vascular in origin; furthermore the marked decrease in capillary macromolecule permeability may explain the serous fluid collection within the hydrosalpinx. Poor fecundity following microsurgical restoration of tubal patency in hydrosalpinges is possibly due to the failure of this decrease in submucosal capillary perfusabüity and macromolecular permeability to resolve.
Immunohistochemical Studies of the Serotonergic Supraependymal Plexus in the Mammalian Ventricular System, with Special Reference to the Characteristic Reticular Ramification
Authors: Matsuura Tadao , Takeuchi Yoshihiro , Kojima Munekado , Ueda Shuichi , Yamada Hisao , Nojyo Yoshiaki , Ushijima Kazuo , Sano Yutaka
Published: July 2008

Distributional and morphological features, especially characteristics of the ramification of serotonin-containing supraependymal fibers (SEF), were studied in the ventricular systems of mammals (mouse, rat, guinea pig, rabbit, cat, dog, monkey) by means of a modified peroxidase antiperoxidase technique, using antiserotonin antiserum prepared in our laboratory. SEF were present in all ventricular systems, except on the third ventricle floor and in the choroid plexus. The density of SEF was higher in the smaller species. In the rat, light- and scanning electron microscopical SEF were almost completely abolished 1 week after intraventricular administration of 5,6-dihydroxytriptamine. Ramification of SEF was complicated; the SEF formed a true network with frequent anastomosing. In the ventricular system of rats rendered hydrocephahc by kaolin administration, the mode of axonal branching in the supraependymal plexus could best be analyzed by the scanning electron microscope because the meshes of the plexus were spread out.
Methylene Blue and Organised Differentiation in the Chick Embryo
Authors: Iyengar Bhanu , Lal S.K.
Published: July 2008

The sub-blastodermal administration of methylene blue at 17 h of incubation gives rise to a mosaic of neuroectodermal differentiation with a disruption of the neural axis at 40 h of incubation. These features appear to be due to the rapid and direct movement of this dye into all the cells of the chick embryo blastoderm, and its binding and breakdown of the cytoplasmic ribose nucleotides, due to which neural tube formation is completely inhibited. The findings are confirmed by combined copper sulphate and methylene blue treatment, as copper is a powerful catalyst of methylene blue activity and binds with RNA.
Photoreceptor Nuclei Outside of the Limiting Membrane in the Chick Retina
Authors: Armengol José A. , Prada Francisco , Génis-Gálvez José M.
Published: July 2008

The present work describes the presence of some photoreceptor nuclei in the embryonic and adult chick retina which are situated outside of the external limiting membrane. We also discuss their possible degenerative character.
Photic Responses of the Retina at Different Ages
Authors: Yew David T. , Tsang David S.C. , Chan Y.W.
Published: July 2008

The alkaline phosphatase and DNA-RNA activities in the retinas of young and old albino mice were determined histochemically after photic exposure. Different patterns between the two age groups were obtained for the alkaline phosphatase reaction before and after photic exposure. In the young animals, more retinal layers showed increased activity after exposure whereas in the old animals, the converse was true. DNA-RNA reaction revealed decreased DNA activities in the old animals 30 h after exposure. The results were also correlated with biochemical studies on the uptake of 2-deoxyglucose, dopamine and leucine.
Evaluation of Cranial Bone Suture Autotransplants in the Growing Rabbit
Authors: Nash Scott B. , Kokich Vincent G.
Published: July 2008

A coronal bone suture segment was autotransplanted into an experimentally created defect in the nongrowing portion of the nasal bone in 12 5-week-old male New Zealand white rabbits. The animals were sacrificed 90 days postoperatively. In most specimens the transplants were well incorporated into the recipient site. The transplanted sutures appeared narrower radiographically, and the bony projections of the sutures were not as long as those seen in control sutures. In each case the transplanted sutural ligament had atrophied, and six of the transplants showed bony union across the sutural space. The results suggest that growth and biomechanical stresses are important for maintenance of the sutural ligament and for the stimulation of bone deposition.
A Morphological Comparison of Aortic Elastin from Five Species as Seen with the Scanning Electron Microscope
Authors: Song S.H. , Roach M.R.
Published: July 2008

The elastic laminae were extracted from thoracic aortas of adult animals including sheep, dogs, rabbits, cats and rats by treating them in hot alkaline solution (0.1 /VNaOH at 75 °C) and observed with a scanning electron microscope. The elastic laminae are comprised of sheet-like internal elastic lamina, fibrous and membraneous elastin in tunica media, interlamellar fibers and hollow spaces which we presume were formerly filled with smooth muscle cells in the tunica media. These structures are the same in all five species except that the number of layers and the total thickness of the wall differs.
Study of Arterial Patterns of the Hand in Primates
Authors: Ugawa A. , Ikeda A.
Published: July 2008

Study of the arterial patterns of the hand in Macaca fuscata, especially those of the deep palmar arterial arches and their correlating arteries, by three-dimensional arteriographic analysis revealed the following: (1) The deep palmar arterial arches are formed by the perforating branches of the 2nd dorsal metacarpal artery, and they are usually composed of two proximal arches (catella volaris proximalis and arcus volaris profundus) and one distal arch (catella volaris distalis). (2) In the 3rd and 4th metacarpal interosseous spaces, the intermetacarpal arteries arise from the catella volaris proximalis, and the arcus volaris profundus has palmar metacarpal arteries which descend along the palmar side of each metacarpal bone. (3) There is a definite regularity in the formation of the intermetacarpal arteries between the catella volaris proximalis and the catella volaris distalis and of the palmar metacarpal arteries between the arcus volaris profundus and the catella volaris distalis.
Embolien beim Embryo
Authors: Schneider M. , Rickenbacher J.
Published: July 2008

Artificial embolisms were produced in chick embryos by injecting small mouse liver cell particles in an extraembryonal vein. 1–10 h after the injection the embryos were fixed, and serial sections were examined by light microscope. Most of the obstructed vessels were later recanalized. All of the emboli were surrounded by thrombocytes and partly fixed on the vessel wall. The smaller of the injected particles were lying outside the vessels in the neighboring mesenchyme. The significance of thrombocytes for this transport mechanism is discussed.
Differentiation of Blood Vessels in the Adipose Tissue of Lean and Obese Fetal Pigs, Studied by Differential Enzyme Histochemistry
Authors: Hausman G.J. , Thomas G.B.
Published: July 2008

Subcutaneous adipose tissue was obtained from fetuses removed from pregnant obese (Ossabaw) and lean (crossbred) sows at three stages of gestation (70, 90, and 110 days). Histochemical analysis for nucleoside phosphatase (NPase), alkaline phosphatase (APase), and NADH tetrazoleum reductase (NADH-TR) was conducted on fresh-frozen cryostat sections. Age- associated changes in NPase and NADH-TR reactions in the arteriolar system were correlated with the morphological development of the medial layer of arterioles and arteries. For instance, a strong NPase reaction in small arterioles was associated temporally with the assumption of a normal smooth muscle cell morphology and arrangement in the medial layer. In the youngest fetuses, strong NADH-TR reactions were only evident in small and presumptive arterioles and venules (associated with fat cells). Little NADH-TR reactivity was evident in larger arterioles and venules in 70-day tissue. Arteries and large arterioles were distinguished from veins and venules (strong reactions vs. weak reactions) with NADH-TR and NPase reactions in the oldest fetuses. In the younger fetuses, the NPase distinction (arterioles vs. veinules) was obvious before NADH-TR distinction. Small adipocyte-associated vessels were APase positive in the youngest fetuses, but APase reactivity was limited to short segments of vessel between arterioles and capillaries in the oldest fetuses. With the following exceptions, all the above observations were independent of fetal strain. In obese fetuses (110 day) small venules and small arterioles were equally reactive for NPase activity. Capillaries in obese fetuses (110 day) were NADH-TR reactive, whereas no activity was evident in capillaries from lean fetuses (110 day). The histology of intimal and medial vessel walls was independent of fetal strain. However, at every fetal age the adventitial layer of large arterioles and the collagenous stroma (around fat cell clusters) was thicker and better organized in obese fetuses. In the present study, differential enzyme histochemistry was utilized to distinguish the differentiation of small adipocyte-associated arterioles from larger arterioles. Furthermore, structural evidence of the arteriolar system clearly precedes metabolic and histological differentiation of tunica media cells. Finally, metabolic and structural traits of the stromal vascular cells of adipose tissue were sensitive to a fetal obese pheno-type.
Placentation in the Opossum, Didelphis virginiana
Authors: Krause William J. , Cutts Harry
Published: July 2008

For the first 9 days of gestation, opossum embryos float in uterine secretions, separated from maternal tissues by a shell membrane. Each embryo is part of the wall of its hollow embryonic sphere. By the 10th day of development, the embryo becomes enveloped by both the amnion and yolk-sac. The yolk-sac consits of vascular and non-vascular portions and, together with the surrounding trophectoderm (trophoblast), forms the yolk-sac placenta of the opossum: the allantois does not contribute to formation of the placenta. The vascular portion of the yolk-sac placenta establishes an intimate relationship with the uterine epithelium soon after loss of the shell membrane. The yolk-sac placenta is non-invasive. Cells of the trophoblast exhibit numerous microvilli, an apical endocytic complex and the lateral and basal cell membrane are elaborately folded. These features suggest a cell that is active in the transport of materials. Junctional complexes between cells of the trophoblast and uterine epithelium were not observed. The uterine epithelium changes from ciliated pseudostratified columnar with few infoldings of lateral and basal cell membranes, to non-ciliated simple columnar in which these membranes show elaborate infoldings. The cells show numerous inclusions and mitochondria are polarized to the basal half of the cell. These features suggest a cell that also is active in the transport of materials.
Ultrastructure of the Rat Pineal Stalk
Authors: Calvo J. , Boya J.
Published: July 2008

The ultrastructure of the rat pineal stalk was described. The pineal stalk contained few pinealocytes, glial cells and numerous nerve fibers. The last were mostly non-myelinated axons, although a few myelinated ones were also observed. Glial cells showed many filaments, mostly in the processes which presented a longitudinal orientation. Other more lamellar processes were found enclosing the axons. The pineal stalk became wider as it reached the body of the gland. Ultrastructurally, this wide region resembled more the pineal body. Bundles of non-myelinated nerve fibers were seen around the pineal stalk.
Quantitative Studies of the Cat Carotid Body
Authors: Pallot D.J. , Al-Neamy K.W. , Blakeman N.
Published: July 2008

The work reported here examines the quantitative ultrastructure of cat carotid body type I cells, and the effects of hypoxia on the cells. On the basis of size and density of electron-dense cored vesicle (EDCV) we were unable to identify more than one major population of type I cells. Prior ventilation of the animals with 10% O2 resulted in an increase in the volume percentage (Vv%) of mitochondria and a decrease in the Vv% of EDCV as compared to the values after ventilation with 100% O2. The lack of effect of prior denervation of the carotid body on the hypoxic changes suggests that the effects are not mediated via an efferent pathway.
Further Regression of Seminal Vesicles of Castrated Guinea Pig by Administration of Cyproterone Acetate
Authors: Tam C.C. , Wong Y.C. , Tang F.
Published: July 2008

It has been established that a low level of secretory activity persisted in seminal vesicles of guinea pigs long after castration and that this may be due to a higher extratesticular androgen level in this animal. A RIA study revealed that the normal serum testosterone concentration of the guinea pigs was comparable to that of the rats, but the basal serum testosterone level after castration was ten times higher than rats under a similar condition. It was also shown that cyproterone acetate did not significantly lower the basal serum testosterone concentration in the castrated guinea pigs. The higher basal serum testosterone level is believed to be responsible for the slow and incomplete regression of this gland in the guinea pigs. There was a significant reduction in wet weight of the seminal vesicles after the treatment of castrated guinea pigs with cyproterone acetate. Ultrastructural study showed that there were both qualitative and quantitative changes in the cytoplasmic organelles. The Golgi apparatus further reduced in size and in the number of associated vesicles and vacuoles. There was a marked decrease in the number and size of secretory granules and lysosomes and an increase in the degree of undulation of the basement membrane. Accumulation of lipid droplets and glycogen was commonly observed. All these morphological evidences showed that further regression of the castrated guinea pig seminal vesicles can be achieved by cyproterone acetate treatment.