bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

AbstractMany 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

AbstractIn 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

AbstractErupted 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

AbstractThe 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

AbstractPrevious 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

AbstractAlterations 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

AbstractThe 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

AbstractThe 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

AbstractTestes 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

AbstractThe 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

AbstractIntrasphenoid 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

AbstractApart 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

AbstractMice 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

AbstractWhile 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.