bluuebunny/crossref_metadata_2025 huggingface dataset:
Simple pressure-tuned Fabry–Pérot interferometer
Authors: Hansis E. , Cubel T. , Choi J.-H. , Guest J. R. , Raithel G.
Published: February 2005

A simple, compact and inexpensive pressure-tuned Fabry–Pérot interferometer is presented. It is used as a laser locking reference for optical frequencies where the use of an atomic reference is impractical. The scanning range is several GHz. Absolute positioning of the interferometer with an accuracy of 7MHz rms over a range of 2GHz is possible. The instrument is temperature stabilized and shows long-term drift of 16MHz rms over 48h.
Active radiometric calorimeter for absolute calibration of radioactive sources
Authors: Stump K. E. , DeWerd L. A. , Rudman D. A. , Schima S. A.
Published: February 2005

This report describes the design and initial noise floor measurements of a radiometric calorimeter designed to measure therapeutic medical radioactive sources. The instrument demonstrates a noise floor of approximately 2 nW. This low noise floor is achieved by using high temperature superconducting (HTS) transition edge sensor (TES) thermometers in a temperature-control feedback loop. This feedback loop will be used to provide absolute source calibrations based upon the electrical substitution method. Other unique features of the calorimeter are (a) its ability to change sources for calibration without disrupting the vacuum of the instrument, and (b) the ability to measure the emitted power of a source in addition to the total contained source power.
Diatom Plastids Possess a Phosphoribulokinase with an Altered Regulation and No Oxidative Pentose Phosphate Pathway
Authors: Michels Andreas K. , Wedel Norbert , Kroth Peter G.
Published: February 2005

The chloroplast enzyme phosphoribulokinase (PRK; EC 2.7.1.19) is part of the Calvin cycle (reductive pentose phosphate pathway) responsible for CO2 fixation in photosynthetic organisms. In green algae and vascular plants, this enzyme is light regulated via reversible reduction by reduced thioredoxin. We have sequenced and characterized the gene of the PRK from the marine diatom Odontella sinensis and found that the enzyme has the conserved cysteine residues necessary for thioredoxin-dependent regulation. Analysis of enzymatic activity of partially purified diatom enzyme and of purified protein obtained by native overexpression in Escherichia coli, however, revealed that under natural redox conditions the diatom enzyme is generally active. Treatment of the enzyme with strong oxidants results in inhibition of the enzyme, which is reversible by subsequent incubation with reducing agents. We determined the redox midpoint potentials of the regulatory cysteine in the PRK from O. sinensis in comparison to the respective spinach (Spinacia oleracea) enzyme and found a more positive redox potential for the diatom PRK, indicating that in vivo this enzyme might not be regulated by thioredoxin. We also demonstrate that in protease-treated diatom plastids, activities of enzymes of the oxidative pentose phosphate pathway are not detectable, thus reducing the need for a tight regulation of the Calvin cycle in diatoms. We discuss our results in the context of rearrangements of the subcellular compartmentation of metabolic pathways due to the peculiar evolution of diatoms by secondary endocytobiosis.
Changes in rain forest tree diversity, dominance and rarity across a seasonality gradient in the Western Ghats, India
Authors: Davidar Priya , Puyravaud Jean Philippe , Leigh Egbert G.
Published: February 2005

Aim We assessed the effects of latitude, altitude and climate on the alpha diversity of rain forest trees in the Western Ghats (WG) of India. We tested whether stem densities, dominance, the prevalence of rarity, and the proportion of understorey trees are significantly correlated with alpha diversity.

Location The WG is a chain of mountainsc.1600 km in length, running parallel to the western coast of the Indian peninsula from above 8° N to almost 21° N latitude. Wet forests occur as a narrow strip in regions with heavy rainfall.

Methods To assess tree diversity we used data from 40 small plots, < 1 ha in area, where all trees ≥ 3.18 cm d.b.h. had been inventoried. These plots were distributed across 7 latitudinal degrees and at elevations between 200 and 1550 m. Fisher's alpha was used as a measure of diversity. For each plot, the proportion of trees belonging to the understorey, the proportion of trees belonging to the most abundant species in the plot, as a measure of dominance, and the proportionate representation of singletons, as a measure of rarity, were estimated, and correlated with Fisher's alpha, elevation, rainfall and seasonality.

Results Annual rainfall and seasonality increased towards the north, but were not significantly correlated. Tree diversity increased significantly with decreasing seasonality. Tree diversity was not significantly correlated with stem density or with the proportion of understorey tree species, but was significantly correlated with tree dominance and rarity. Dominance increased and rarity significantly decreased with increasing seasonality.

Main conclusions This study demonstrates that seasonality influences rain forest tree diversity in the WG of India. The relationship between alpha diversity, dominance and rarity lends correlative support for the Janzen–Connell pest pressure hypothesis.
Effects of Clenbuterol on Haemocoagulation Process in Calves
Authors: Domina F. , Niutta P. P. , Naccari C. , Pugliese A. , Naccari F.
Published: February 2005

The aim of this investigation was to study the effects of clenbuterol treatment (1 μg/kg b.w. i.m. for 10 consecutive days) on haemocoagulation process in seven calves. From each animal, blood samples were taken before (basal sample) and 24, 72, 144, 216, 264, 336 and 360 h after the end of treatment and some parameters were evaluated: coagulation process [prothrombin (PTT) and thrombin times (PT)], a complete blood count and plasmatic levels of 3′5′‐monophosphatocyclic‐adenosine (c‐AMP) . A comparison of the values in each time group during the whole course of the experiments shows a significant increase (P < 0.03, P < 0.01) in PT and PTT at 72, 144, 216 and 264 h. Significant increase (P < 0.01) in c‐AMP plasma levels were observed at 144, 216 and 264 h. All these values returned to normal levels after 360 h.
Novel method for measurement of medium size arterial lumen area with an impedance catheter: in vivo validation
Authors: Kassab Ghassan S. , Lontis Eugen R. , Hørlyck Arne , Gregersen Hans
Published: February 2005

There is no doubt that the transformation of a cardiac catheter into a conductance catheter that allows reliable and accurate assessment of lumen cross-sectional area (CSA) will provide a powerful diagnostic and treatment tool for the invasive cardiologist. The objective of this study was to develop a method based on the impedance catheter that allows accurate and reproducible measurements of CSA for medium size vessels (e.g., coronary, femoral, and carotid arteries). Two solutions of NaCl (0.5% and 1.5%) with known conductivities were injected directly into the lumen of the artery in eight swine. We showed that the CSA can be determined analytically from two Ohm's law-type algebraic equations that account for the parallel conductance of the current into the surrounding tissue. Excellent agreement was found between the conductance catheter with the proposed two-injection method and B-mode ultrasound (US). The root mean square error for the impedance measurements was 4.8% of the mean US diameter. The repeatability of the technique was assessed with duplicate measurements. The mean of the difference between the two measurements was nearly zero, and the repeatability coefficient was within 2.4% of the mean of the two measurements. The validated method was used to assess the degree of acute vasodilatation of the vessel in response to flow overload.
Radionuclide plethysmography for noninvasive evaluation of peripheral arterial blood flow
Authors: Harel François , Dupuis Jocelyn , Benelfassi Ahmed , Ruel Nathalie , Grégoire Jean
Published: February 2005

We validated a noninvasive radionuclide plethysmography technique to evaluate peripheral arterial blood flow during reactive hyperemia. This method, based on the measurement of blood volume variations during repetitive venous occlusions, was compared with strain-gauge venous impedance plethysmography. The technique uses 99mTc-labeled autologous red blood cells scintigraphy to determine the rate of change of forearm scintigraphic counts during venous occlusion. Thirteen subjects were simultaneously evaluated with radionuclide and impedance plethysmography. Six baseline flow measurements were performed to evaluate the reproducibility of each method. Twenty-seven serial measurements were then made to evaluate flow variation during forearm reactive hyperemia. After 30 min of recovery, resting forearm blood flows were again evaluated. Impedance and radionuclide methods showed excellent reproducibility with intraclass correlation coefficients of 0.96 and 0.93, respectively. There was also good correlation of flows between both methods during reactive hyperemia ( r = 0.87). Resting flows at 30 min after reactive hyperemia were slightly lower than at baseline with both methods. We conclude that radionuclide plethysmography could be used for the noninvasive evaluation of forearm blood flow and its dynamic variations during reactive hyperemia.
Monitoring the initial pulmonary absorption of two different beclomethasone dipropionate aerosols employing a human lung reperfusion model
Authors: Freiwald Matthias , Valotis Anagnostis , Kirschbaum Andreas , McClellan Monika , Mürdter Thomas , Fritz Peter , Friedel Godehard , Thomas Michael , Högger Petra
Published: February 2005

Background

The pulmonary residence time of inhaled glucocorticoids as well as their rate and extend of absorption into systemic circulation are important facets of their efficacy-safety profile. We evaluated a novel approach to elucidate the pulmonary absorption of an inhaled glucocorticoid. Our objective was to monitor and compare the combined process of drug particle dissolution, pro-drug activation and time course of initial distribution from human lung tissue into plasma for two different glucocorticoid formulations.

Methods

We chose beclomethasone dipropionate (BDP) delivered by two different commercially available HFA-propelled metered dose inhalers (Sanasthmax®/Becloforte™ and Ventolair®/Qvar™). Initially we developed a simple dialysis model to assess the transfer of BDP and its active metabolite from human lung homogenate into human plasma. In a novel experimental setting we then administered the aerosols into the bronchus of an extracorporally ventilated and reperfused human lung lobe and monitored the concentrations of BDP and its metabolites in the reperfusion fluid.

Results

Unexpectedly, we observed differences between the two aerosol formulations Sanasthmax®/Becloforte™ and Ventolair®/Qvar™ in both the dialysis as well as in the human reperfusion model. The HFA-BDP formulated as Ventolair®/Qvar™ displayed a more rapid release from lung tissue compared to Sanasthmax®/Becloforte™. We succeeded to explain and illustrate the observed differences between the two aerosols with their unique particle topology and divergent dissolution behaviour in human bronchial fluid.

Conclusion

We conclude that though the ultrafine particles of Ventolair®/Qvar™ are beneficial for high lung deposition, they also yield a less desired more rapid systemic drug delivery. While the differences between Sanasthmax®/Becloforte™ and Ventolair®/Qvar™ were obvious in both the dialysis and lung perfusion experiments, the latter allowed to record time courses of pro-drug activation and distribution that were more consistent with results of comparable clinical trials. Thus, the extracorporally reperfused and ventilated human lung is a highly valuable physiological model to explore the lung pharmacokinetics of inhaled drugs.
Comparison of patterns of use, beliefs, and attitudes related to waterpipe between beginning and established smokers
Authors: Asfar Taghrid , Ward Kenneth D , Eissenberg Thomas , Maziak Wasim
Published: February 2005

Background

To compare patterns of use, beliefs, and attitudes related to waterpipe smoking between university students (beginning smokers) and café customers (established smokers) in Aleppo Syria, in order to explore the evolution of this smoking method.

Methods

Two cross-sectional surveys were conducted among representative samples of university students (total 587, 48.4% men, mean age 22 years), and waterpipe users among cafe' customers (total 268, 60% men, mean age 30 years) in Aleppo, Syria. We used interviewer-administered questionnaire inquiring about pattern of waterpipe smoking (initiation, frequency), situational characteristics of use (partner, place, sharing), beliefs related to waterpipe smoking (harmful/addictive properties of waterpipe), attitudes related to waterpipe smoking (confidence in quitting, will to quit, motivation for quitting, past year quit attempt), and cigarette smoking.

Results

Daily and regular patterns of smoking become more prevalent with increased duration of smoking, but intermittent smoking remains the predominant pattern of waterpipe use. Women seem to be drawn later to the habit, which seem to escape the usual taboo against women's cigarette smoking. Patterns and context of waterpipe use tend to change with progress of the practice affecting frequency, setting, and sharing of waterpipe. Unlike beginners, established waterpipe smokers seem more smoking-method oriented, more hooked on the habit, less willing to quit, and less likely to foresee challenges to quitting.

Conclusion

Use patterns and attitudes related to waterpipe smoking evolve to accommodate the change in dependence and life circumstances of the smoker. Most of use features, beliefs, attitudes, as well as time-course seem unique to this smoking method requiring novel approach to intervention.
Colorectal cancer metastasis: in the surgeon's hands?
Authors: Atkin Gary , Chopada Abhay , Mitchell Ian
Published: February 2005

Background

Lymphovascular ligation before tumour manipulation during colorectal cancer resection is termed the 'no-touch isolation' technique. It aims to reduce the intra-operative dissemination of colorectal cancer cells. Recently, the detection of circulating tumour cells has been enhanced by molecular biology techniques. This paper reviews the evidence for the no-touch isolation technique in light of the recent developments in circulating tumour cell detection.

Methods

Studies investigating the effect of colorectal cancer surgery on circulating tumour cells were identified by a Medline search using the subject headings colorectal neoplasms and neoplasm circulating cells together with the map term 'no-touch isolation technique'. Further references were obtained from key articles.

Results

Molecular biological techniques have improved the detection of circulating colorectal cancer cells. There is a trend towards reduced tumour cell dissemination with the no-touch technique compared with the conventional method. However the benefit in terms of improved patient survival remains unproven.

Conclusion

The no-touch isolation technique reduces circulating tumour cell dissemination but further work is needed to determine the significance of this with regards to patient survival.
A giant subcutaneous leiomyosarcoma arising in the inguinal region
Authors: Yajima Kazuhito , Shirai Yoshio , Fujita Nobuhiro , Sato Daisuke , Umezu Hajime , Hatakeyama Katsuyoshi
Published: February 2005

Background

Subcutaneous leiomyosarcoma is a rare condition that accounts for 1% to 2% of all superficial soft tissue malignancies. Approximately 10% of cases arise in the trunk, although the extremities are the most commonly affected.

Case presentation

We report herein the case of a 31-year-old man with a subcutaneous leiomyosarcoma, measuring 124 × 105 mm, arising in the left inguinal region. A wide local excision (with a resection margin ≥ 20 mm) was performed. Histological examination of the resected specimen revealed a leiomyosarcoma with high cellularity and two mitoses per 10 high-power fields. The patient remains well with no evidence of disease 5 years and 8 months after the operation.

Conclusion

This is the first reported case of subcutaneous leiomyosarcoma arising in the inguinal region and also one of the largest tumors reported. The experience of this case and a review of the English-language literature (PubMed, National Library of Medicine, Bethesda, MD, USA) suggest that a resection margin of ≥ 10 mm is recommended when excising this rare tumor.
The health workforce crisis in TB control: a report from high-burden countries
Authors: Figueroa-Munoz José , Palmer Karen , Dal Poz Mario R , Blanc Leopold , Bergström Karin , Raviglione Mario
Published: February 2005

Background

Human resources (HR) constraints have been reported as one of the main barriers to achieving the 2005 global tuberculosis (TB) control targets in 18 of the 22 TB high-burden countries (HBCs); consequently we try to assess the current HR available for TB control in HBCs.

Methods

A standard questionnaire designed to collect information on staff numbers, skills, training activities and current staff shortages at different health service levels was sent to national TB control programme managers in all HBCs.

Results

Nineteen HBCs (86%) replied, and 17 (77%) followed the questionnaire format to provide data. Complete information on staff numbers at all service levels was available from nine countries and data on skill levels and training were complete in six countries. Data showed considerable variations in staff numbers, proportions of trained staff, length of courses and quality of training activities. Eleven HBCs had developed training materials, many used implementation guidelines for training and only three used participatory educational methods. Two countries reported shortages of staff at district health facility level, whereas 14 reported shortages at central level. There was no apparent association between reported staff numbers (and skills) and the country's TB burden or current case detection rates (CDR).

Conclusion

There were few readily available data on HR for TB control in HBCs, particularly in the larger ones. The great variations in staff numbers and the poor association between information on workforce, proportion of trained staff, and length and quality of courses suggested a lack of valid information and/or poor data reliability. There is urgent need to support HBCs to develop a comprehensive HR strategy involving short-term and long-term HR development plans and strengthening their HR planning and management capabilities.
Erythropoietin response in critically ill mechanically ventilated patients: a prospective observational study
Authors: DeAngelo Alan J , Bell David G , Quinn Michael W , Long Deborah Ebert , Ouellette Daniel R
Published: February 2005

Introduction

Anemia is a common problem in critically ill patients. The etiology of anemia of critical illness is often determined to be multifactorial in the clinical setting, but the pathophysiology remains to be elucidated. Erythropoietin (EPO) is an endogenous glycoprotein hormone that serves as the primary stimulus for erythropoiesis. Recent evidence has demonstrated a blunted EPO response as a factor contributing to anemia of critical illness in specific subsets of patients. Critically ill patients requiring mechanical ventilation who exhibit anemia have not been the subject of previous studies. Our goal was to evaluate the erythropoietic response to anemia in the critically ill mechanically ventilated patient.

Methods

A prospective observational study was undertaken in the medical intensive care unit of a tertiary care, military hospital. Twenty patients admitted to the medical intensive care unit requiring mechanical ventilation for at least 72 hours were enrolled as study patients. EPO levels and complete blood count were measured 72 hours after admission and initiation of mechanical ventilation. Admission clinical and demographic data were recorded, and patients were followed for the duration of mechanical ventilation. Twenty patients diagnosed with iron deficiency anemia in the outpatient setting were enrolled as a control population. Control patients had baseline complete blood count and iron panel recorded by primary care physicians. EPO levels were measured at the time of enrollment in conjunction with complete blood count.

Results

The mean EPO level for the control population was 60.9 mU/ml. The mean EPO level in the mechanically ventilated patient group was 28.7 mU/ml, which was significantly less than in the control group (P = 0.035). The mean hemoglobin value was not significantly different between groups (10.6 g/dl in mechanically ventilated patients versus 10.2 g/dl in control patients; P > 0.05).

Conclusion

Mechanically ventilated patients demonstrate a blunted EPO response to anemia. Further study of therapies directed at treating anemia of critical illness and evaluating its potential impact on mechanical ventilation outcomes and mortality is warranted.
Postmastectomy Radiation and Mortality in Women With T1-2 Node-Positive Breast Cancer
Authors: Smith Benjamin D. , Smith Grace L. , Haffty Bruce G.
Published: February 2005

Purpose

To determine the relationship between postmastectomy radiotherapy (PMRT) and mortality in a population-based cohort of women with T1-2 node-positive breast cancer.

Patients and Methods

Using data from the Surveillance, Epidemiology, and End Results program, we identified 18,038 women with T1-2 node-positive invasive breast cancer who were treated with mastectomy between 1988 and 1995. The relationship between PMRT and mortality was determined using proportional hazards multivariate modeling and propensity score matched case-control analysis.

Results

Median follow-up was 8.1 years. Only 2,648 women (15%) received PMRT. After adjusting for covariates, PMRT use was not associated with mortality (hazard ratio [HR] = 0.96; 95% CI, 0.90 to 1.03). However, the interaction term for PMRT use and number of involved regional lymph nodes was significant (P = .002), suggesting that, above a certain threshold of involved nodes, a mortality benefit from PMRT may exist. Adjusted analysis stratified by number of involved nodes revealed that patients with seven or more involved nodes treated with PMRT experienced a significant reduction in all-cause (HR = 0.84; 95% CI, 0.76 to 0.93) and cause-specific mortality (HR = 0.86; 95% CI, 0.77 to 0.96). Propensity score matched case-control analysis confirmed that PMRT was associated with reduced mortality only in the subset of patients with seven or more involved nodes (HR = 0.81; 95% CI, 0.73 to 0.91 for all-cause mortality; and HR = 0.82; 95% CI, 0.72 to 0.93 for cause-specific mortality).

Conclusion

For women with T1-2 breast cancer, PMRT is associated with a 15% to 20% relative reduction in mortality for patients with seven or more involved regional lymph nodes.
The fine structure of the supramedullary neurons of the puffer with special reference to endocellular and pericellular capillaries
Authors: Nakajima Y. , Pappas G. D. , Bennett M. V. L.
Published: February 2005

Many capillaries are embedded in the cytoplasm of large supramedullary neurons (about 200 to 300 μ in diameter). Fewer such capillaries are seen in the smaller neurons (about 80 to 100 μ in diameter). The neuron clusters remain unstained after vital staining with trypan blue indicating presence of the blood‐brain barrier. Electron microscopic studies show that the capillary lumen is lined by nonfenestrated endothelial cells, pericytes, and a continuous basement membrane. Glial cell processes consisting mostly of astrocytes abut onto the capillary basement membrane separating the capillary from the neuron. The continuous glial investment around blood vessels may play a role in maintenance of the blood‐brain barrier. The nucleus in supramedullary cells is roughly circular and contains one large and several small nucleoli. The perikaryon contains neurofilaments, diffusely distributed elements of endoplasmic reticulum, clusters of RNP granules, Golgi complex, mitochondria, multivesicular bodies, and inclusion bodies; but is devoid of elementary neurosecretory granules. The cell body of the neuron is entirely covered by glial cells, often with processes which deeply indent the soma surface. Neither synapses nor arborizing dendrites are found on the cell body.
An electron microscopic visualization of transport across rat visceral yolk sac
Authors: Lambson Roger O.
Published: February 2005

In an attempt to elucidate some of the mechanisms utilized in the placental transfer of large molecules morphological changes in the visceral yolk sac have been studied in relation to the disposition of ferritin molecules at different stages of gestation.

From the tenth through the eighteenth days of pregnancy, ferritin molecules were readily absorbed by the visceral endodermal cells when this material was injected either into the maternal blood stream or directly into the uterine lumen. These large molecules entered the endodermal cells through a progressively developed apical canalicular system and became localized within relatively large, heterogenous vacuoles. These vacuoles were seen to retain the ferritin for long periods, except during the last few days of gestation. At the end of pregnancy, when normally antibodies are being transferred in the largest quantities to the fetus, relatively smaller vesicles which contain ferritin appeared to have migrated away from the larger apical storage vacuoles and to have approached the endodermal basal plasma membrane. Once the large protein molecules left these cells they appeared to pass either directly into vitelline capillaries, or through mesothelial cells which line the exocoelom.

Transport of large protein molecules through visceral endodermal cells involves an apical tubular system, large storage vacuoles, and smaller vesicles which appear to migrate basally near the end of pregnancy. Regulation of this process appears not to depend on the failure or success of entry of such a substance into these cells, but rather on its subsequent disposition once it is intracellular.
Electron microscopic study of the gingivo‐dental junction of man
Authors: Listgarten Max A.
Published: February 2005

Erupted teeth with attached gingival tissue were obtained from 15 patients ranging in age from 4 to 26 years. After preliminary glutaraldehyde fixation, the area to be studied was excised with a high speed dental drill. The tissue was decalcified in Versene, subdivided into smaller blocks and post‐fixed in 2% buffered osmic acid fixative. Epon embedded sections were stained with uranyl acetate and lead citrate prior to being examined in the electron microscope.

The results indicate that (1) an attachment is present between the epithelial cuff and enamel or cementum, (2) the attachment apparatus of epithelium to tooth structure consists of hemidesmosomes and a cementing layer resembling the basement lamina of various epithelium‐connective tissue junctions, (3) the attachment may be to two types of cuticle of undetermined origin, or directly to the tooth, and (4) apical to the epithelial attachment the gingiva is connected to cementum by parallel bundles of collagen fibrils which extend from the gingiva into the cementum. The cementum itself consists of parallel collagen fibrils the periodicity of which is in register between adjacent fibrils. The fibrils are embedded in a rather sparse, granular matrix.
A histochemical study of the esterases of the rat heart
Authors: Hegab El‐Sayed H. H. , Ferrans Victor J.
Published: February 2005

The histochemistry of esterases was studied in the rat heart, using various methods of tissue preparation and a large number of substrates, inhibitors and activators.

Non‐specific esterase and cholinesterase was demonstrated in the fibers of the atrioventricular conduction system, in atrial and ventricular muscle fibers, in cardiac neurons and in some of the nerve fibers of the heart. The highest concentration of both types of enzymes was found in the conduction system and in the neural elements. Pericytes and macrophages showed only non‐specific esterase activity.

Two broad types of non‐specific esterase activity, cytoplasmic and lysosomal, were distinguished in the pericytes, macrophages and cardiac muscle fibers by the use of selective inhibitors and activators. The cytoplasmic activity is due to the presence of B and C esterases and was better demonstrated with esters of a‐naphthol than with naphthol AS derivatives or indigogenic esters. The esterase activity of lysosomes appears to be due to a group of fluoride‐ and organophosphate‐resistant enzymes, some of which are probably cathepsins.
Localization of uptake of tritiated norepinephrine by rat brain in vivo and in vitro using electron microscopic autoradiography
Authors: Lenn Nicholas J.
Published: February 2005

Previous studies have identified granular vesicles in peripheral adrenergic axons, and larger granular vesicles in various brain regions which seem to be correlated with the presence of norepinephrine. In the present study, electron microscopic autoradiography was used to localize 3H‐norepinephrine taken up by brain slices in vitro and by brain in vivo after injection via the lateral ventricle. In both preparations, the label was found predominantly in relation to small, unmyelinated axons and nerve endings. Many of these contained granular vesicles in axons which were located in regions of the brain known to contain norepinephrine. It is suggested on the basis of this study and previous work, that exogenous norepinephrine is accumulated by brain axons and nerve endings which contain endogenous norepinephrine, and that the presence of granular vesicles is a common feature of such structures.
Changes in cells, matrix and water of calcifying turkey leg tendons
Authors: Engel Milton B. , Zerlotti Eugenio
Published: February 2005

Alterations in morphology and composition of ossifying turkey leg tendons were followed using biophysical and histochemical procedures in combination with improved methods of tissue preparation. The principal biophysical changes accompanying calcification were loss of water, increase in shrinkage temperature, shifts in form birefringence curves and increased resistance to the disrupting effects of potassium iodide. Fibroblasts of the tendon were modified to cuboidal cells; at the same time, intracellular lipid increased and presumptive secretion of glycoproteins and lipids into the contiguous matrix was observed. As the bony tendon matured, osteocytes appeared and the stainability of the matrix with the periodic acid‐Schiff reagent and dinitrofluorobenzene was markedly diminished. The matrix changes were interpreted as representing increased cross‐linking of a negatively charged biological polyelectrolyte. Concurrently, diminished binding of calcium, the formation of hydrophobic lipid‐containing phases and the lowering of dielectric constant favor the precipitation of bone salts. During calcification, barriers to diffusion, including low vascularity, tend to create a closed, or partially closed, system in the tissue. Then, the mineral phases form with minimal transfer of electrolytes to the circulation. According to the phase rule, the formation of insoluble bone salts stabilizes the heterogeneous biological structure.
The distribution of cholinergic and adrenergic nerves in the mammalian epididymis a comparative histochemical study
Authors: El‐Badawi Ahmad , Schenk Eric A.
Published: February 2005

The distribution of cholinergic and adrenergic nerves in the epididymis was studied in the dog, cat, rat and rabbit using specific histochemical techniques for acetylcholinesterase and norepinephrine. Both cholinergic and adrenergic nerves are associated with tunical, septal and interstitial blood vessels, run independently in the intertubular connective tissue, and surround the epididymal tubules.

Throughout the epididymis there are rich adrenergic and cholinergic perivascular plexuses. The distribution and pattern of interstitial and peritubular cholinergic and adrenergic nerves vary in the three anatomical regions of the epididymis in different animals. In the dog and cat the nerves form plexuses in relation to the ductuli efferentes in the caput, and run as isolated fibers in the corpus epididymidis. In the rat and rabbit there are no interstitial or peritubular nerves in the caput and proximal part of the corpus and few nerves in the distal part of the corpus. The cauda epididymidis is the most richly innervated part of the epididymis. Both interstitial and peritubular cholinergic and adrenergic nerves form plexuses of nerve fibers and bundles, which progressively become more prominent and more intricate as the cauda is traced distally towards its junction with the vas deferens. These changes in innervation pattern follow the distalward increase in thickness of the muscular wall of the ductus epididymidis and are noted in all animals studied.

Ganglia are encountered only in the caput epididymidis in the cat. Cholinergic and adrenergic epithelial fibers are present in the caput and cauda but not in the corpus epididymidis. In the cauda they penetrate through most of the thickness of the epithelium; the cholinergic fibers in this region form a loose intra‐epithelial plexus.
Electron microscopy of the early postnatal development of fibrous astrocytes
Authors: Vaughn James E. , Peters Alan
Published: February 2005

The early postnatal development of fibrous astrocytes in rat optic nerves, has been studied with the electron and light microscopes. At birth, immature astrocytes form approximately 85% of the total cell population, and they have many features in common with the fibrous astrocytes of adult optic nerve. They are stellate cells whose processes form both the glia limitans and the glial sheets which group the axons into fascicles. However, in respect to their cytoplasmic characteristics, immature and mature astrocytes differ considerably. Early postnatal astrocytes have a more electron‐dense cytoplasmic matrix containing an extensive array of organelles. Many microtubules occur in the processes of immature astrocytes, but the characteristic filaments of adult fibrous astrocytes are very sparse. During development, the number of microtubules decreases while the filaments increase until all cytoplasmic areas not occupied by organelles are filled by filaments. This suggests that filaments may be derived from the breakdown of microtubules. This and other possible functions of microtubules in developing astrocytes are discussed.
The fine structure and development of the peritubular contractile cell component in the seminiferous tubules of the mouse
Authors: Ross Michael H.
Published: February 2005

Testes of sexually mature, as well as newborn and young mice of varying ages were studied by electron microscopy. The seminiferous tubules in the mature mouse possess a single cell layer of extremely flattened cells which form a sheath‐like structure around the epithelium of the tubule. These peritubular cells are characterized by cytoplasmic filaments and other features which are typical of smooth muscle cells. A basement lamina is associated with the interstitial or peripheral surface of the cell. Peripherally, there is an additional cellular layer consisting of connective tissue fibrocytes.

In newborn animals, the cells surrounding the tubule epithelium consist of a homogeneous population of fibroblasts, 3–4 layers in thickness. With growth and development of the testes the number of cell layers is reduced and the cells become more attenuated. At 13 days, those cells which are closest to the epithelium show localized aggregates of fine filaments, as well as what appears to be the elaboration of a basement lamina. By 17 days, the cytoplasmic filaments are more numerous and the basement lamina is well defined: by 19 days, the cells closely resemble the peritubular muscle cells of the adult.

The probable functional role of these cells is discussed with respect to both sperm transport and the production and maintenance of the surrounding connective tissue stroma.
The effects of hypophysectomy on the digestive glands of the mouse
Authors: Koerker Richard Mortson
Published: February 2005

The objective was to observe the influence of hypophysectomy on the secretory cells of digestive glands in the mouse and to compare these findings with those reported for other mammalian species. Hypophysectomy of the mouse induced involutional changes in glandular cells concerned with secretion of proteins and mucins, and in those involved in ion transport or release. Gastric chief cells, pancreatic acinar cells, and serous cells of submandibular tubules were markedly involuted; acinar cells of the parotid gland were changed less significantly. Gastric mucous neck cells and mucous acinar cells of the submandibular and sublingual glands contained less secretory material. A colloidal iron‐positive variety of mucous neck cell became dominant. These changes were less profound than those which occurred in most types of zymogenic cells. Parietal cells became atrophic and contained a greatly contracted intracellular canalicular system. Salivary ducts of the parotid and sublingual glands showed partial involution. It was concluded that, as in the rat and man, protein‐secreting cells of the digestive tract of the mouse depend on the support of pituitary hormones. Those cells which secrete mucopolysaccharides or are involved in ion transport also require pituitary hormones for complete maintenance of their structure and function.
The avian intercarotid anastomosis and its homologue in other vertebrates
Authors: Baumel Julian J. , Gerchman LeRoy
Published: February 2005

Intrasphenoid and intrasellar segments of the cerebral carotid arteries were dissected in 82 specimens of birds, representing 21 avian orders. The configuration and branching of these carotid segments and the intercarotid anastomosis were observed.

A well develop intercarotid anastomosis unites the two carotids directly caudal to the hypophysis in all birds examined except for five specimens of passeriform birds of the Suborder Tyranni. Three principal patterns occur: an H‐type having a lengthy transverse anastomosis connecting the carotids; an X‐type with the carotids anastomosing side‐to‐side; and an I‐type with the carotids merged into a single longitudinal vessel. Patterns for each species are illustrated.

Since ordinarily birds lack a cerebral arterial circle comparable to that of mammals. the intercarotid anastomosis obviously serves as its substitute. Evidence of correlation between asymmetry of caudal rami of the cerebral carotids and form of the intercarotid anastomosis is presented.

A communication between cerebral carotids caudal to the hypophysis seems to be a deep‐rooted vertebrate characteristic. An intercarotid anastomosis, apparently homologous to that of birds, occurs in a number of cartilaginous fishes, reptiles, and mammals. In mammals the intercarotid anastomosis is a communication between right and left posterior hypophyseal arteries.
The relationship between the transverse tubular system and other tubules at the Z disc levels of myocardial cells in the ferret
Authors: Simpson F. O. , Rayns D. G.
Published: February 2005

Apart from cytoplasmic microtubules, which exist in cardiac muscle as in most other tissues, there are two tubular systems in mammalian myocardial cells — the transverse (T) tubules which are invaginations of the sarcolemma (i.e., plasma membrane and basement membrane) and the finer tubules which appear to be separate from the transverse system and which have hitherto been known as longitudinal (L) tubules. Because so many of these finer tubules are transversely orientated it seems better to call them simply “sarcotubules.” The sarcotubular system is best envisaged as a three‐dimensional network extending throughout the cell, with specialized areas of flattened sarcotubular sacs at points of contact with the plasma membrane or its extensions in the transverse tubular system. A particularly constant element of the sarcotubular system is found encircling the myofibrils at the Z regions.
The effects of essential fatty acid deficiency on the skin of the mouse
Authors: Menton David N.
Published: February 2005

Mice raised from weaning on a diet free of essential fatty acids (EFA) developed a syndrome involving scaliness and inelasticity of the skin with extensive loss of hair. Histologically, the epidermis of EFA‐deficient mice became noticeably thicker within as few as ten days on the diet and reached a maximum thickness in all strata of the epidermis by 50 days. Animals on the same diet supplemented with 50 mg of purified linoleic acid every other day developed none of the symptoms of deficiency. Mitotic counts on whole‐mounted epidermal sheets split from the foot pads of EFA‐deficient and linoleic acid‐supplemented mice revealed significantly greater mitotic activity in the deficient animals. Histochemical activity for succinic dehydrogenase and cytochrome oxidase was more intense and extensive in the lower stratum Malpighii of the deficient animals than in controls. Acid phosphatase activity also was more intense in the stratum granulosum of deficient animals. These observations are interpreted to indicate that in the mouse cellular proliferation and differentiation of the epidermis are accelerated by essential fatty acid deficiency.
Dense granules (lysosomes?) and crystals in the thyroids of senile rats
Authors: Youson John , Van Heyningen H.
Published: February 2005

While all follicular cells display some dense “lysosome‐like” granules (0.1–2.5 μ), they are more numerous and complex in animals of 14 months or older. There are various types of granules which share some morphological features, but vary in the extent to which they accumulate dense membranous fragments and droplets (0.02–0.4 μ) within their matrices.

Crystalline inclusions are also found in the follicular cells of these older animals, and morphological similarities to dense granules suggest that the crystals may be derived from the granules.
Articular and internal remodeling in the human otic capsule
Authors: Gussen Ruth
Published: February 2005

A comprehensive histologic study of the human otic capsule is presented demonstrating the interrelations between cartilage, bone, blood vessels and soft tissue throughout life. Remodeling occurs through continual degeneration of chondrocytes within the uncalcified articular surfaces of the stapediovestibular joint and through continual degeneration of cartilage about the cochlea and semicircular canals. Degenerated chondrocytes are removed by macrophages and new endochondral bone forms from adjacent osteogenically active blood vessels. The cartilage surfaces of the footplate and oval window are constantly replenished by new cartilage formed by mesenchymal cells of the annular ligament. Within the otic capsule, new cartilage forms from mesenchymal cells lining the labyrinth. Cartilage foci continually undergo partial replacement by endochondral bone with remnants of uncalcified cartilage matrix remaining, forming globuli ossei and interglobular spaces. In addition to continual endochondral bone formation partially replacing the continually forming and degenerating cartilage, chondroid bone forms by direct transformation of some cartilage to bone. These chondroid bone areas are cellular in young age groups, but become pale and relatively acellular with age. These processes occur throughout life, regardless of age or sex.
Formation and structure of the hemodichorial chorio‐allantoic placenta of the bat (Myotis lucifugus lucifugusy)
Authors: Enders Allen C. , Wimsatt William A.
Published: February 2005

The definitive chorio‐allantoic placenta of the bat is hemodichorial, since the cytotrophoblast layer persists to term. The syncytium contains intrasyncytial lacunae in which there is a continuous lamina interrupted only where portions of the syncytium communicate with the thin ectoplasmic layer at the surface of the maternal blood spaces.

The future cytotrophoblast and syncytial trophoblast layers can be distinguished shortly after implantation. The future syncytial layer is not syncytial until after it invests most of the anastomotic vessels of the vascular tuft. The resulting labyrinth is converted from the vaso‐chorial to the hemodichorial condition as processes of syncytium pass through the basement membrane of the maternal vessels and spread out under the endothelial cells. The basement membrane is then included within the syncytium as the intrasyncytial lamina, and the maternal endothelial cells are lost. The numerous communications of the maternal vessels with the labyrinth seen early in gestation are reduced through occlusion of many of the efferent channels, which process also contributes areas of necrosis to the decidua basalis. The peculiarity of a maternal extracellular membrane being incorporated into the fetal portion of the placenta is discussed.
A comparative morphologic study of the cardiac innervation in domestic animals I. The canine
Authors: McKibben John Scott , Getty Robert
Published: February 2005

Cardiac nerves arising from the cervical and thoracic sympathetic chain, the vagi, and the recurrent laryngeal nerves of the dog were described. The findings are correlated with the nomenclature of the NA ('66) and proposals of the NAV ('67), and additional suggestions are made when appropriate. Although individual cardiac nerves were followed to specific areas of the heart, additional supplies to these areas were noted from the cardiac plexus. Sympathetic cardiac innervation arose primarily from the vertebral ganglion. Cranial vagal cardiac nerves on the left and caudal vagal cardiac nerves on the right contributed the majority of the parasympathetic cardiac innervation. Right cardiac nerves ramified primarily along the right coronary artery, left descending branch of the left coronary artery, circumflex branch of the left coronary artery on the left surface of the heart, and onto the right atrium. Left heart nerves, in addition to their direct contributions to all but the last area, proceeded along the circumflex branch of the left coronary artery on the caudal and right surfaces of the heart. Right nerves contributed more in the area of the S.A node, while left nerves formed a network in the area of the coronary sinus and A.V. node. Both sympathetic and parasympathetic nerves were followed to each area. It was noted that pulmonary innervation via the cardiac plexus would be disturbed by the technique of cardiac denervation referred to as regional neural ablations.
Nerve endings in the human endocardium
Authors: Johnston Brian D.
Published: February 2005

The endocardium of 12 human hearts was studied following methylene blue perfusion and immersion within eight hours after death. Photomicrographs presented show two major types of endings: complex unencapsulated endings, and end‐nets. Complex unencapsulated endings are discrete, much branched, highly variable “bush‐like” endings, which originate from myelinated fibers. These structures were found only in the atria, and particularly at atrio‐venous junctions. The close resemblance of complex unencapsulated endings to stretch receptors seen in other tissues suggests that they serve as “baroreceptors” in the heart. End‐nets are composed of repeatedly branching and anastomosing fine beaded fibers. The fine, beaded fibers originate from myelinated fibers, but the number and origin of the parent fibers is not known. In this study, end‐nets were found in the atria, on the atrioventricular valves, and in the ventricular endocardium. The function of the end‐net is unknown, and while most evidence suggests that it is sensory, motor function cannot be ruled out.