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At least 343 records · Page 19Linked to original sources
PubMed2000

Collaborative work to evaluate toxicity on male reproductive organs by repeated dose studies in rats 18). Comparative 4 and 2 weeks oral repeated dosing studies on male reproductive organs in rats treated with 5-fluorouracil.

Oral repeated toxicity studies were conducted to compare the effects of 5-fluorouracil (5-FU) administered for 4 or 2 weeks on male reproductive organs of Sprague-Dawley (SD) rats. In both studies, decrease of feces, abnormal fur and emaciation were observed. On gross autopsy examination, softening/atrophy of the testis as well as atrophy of accessory reproductive organs were noted, and absolute organ weights of male reproductive organs were almost all reduced in both studies. Histopathologically, degeneration of the seminiferous epithelium in the testis and desquamated cell debris in the epididymal ducts were apparent after both time periods. In the 2-week study, furthermore, exfoliation of the seminiferous epithelium, formation of multinucleated giant cells and vacuolation of Sertoli cells in the seminiferous tubules in the testis, and decrease of sperms in the epididymal ducts were observed. The present results indicated that a 2-week study is sufficient to detect effects on the male reproductive organs of 5-FU treatment. In our study, however, changes in associated parameters after 2-week treatment of 8-week-old rats were greater than those after 4 weeks in 6-week-old rats. Thus, for detection of 5-FU-induced male reproductive toxicity, we can evaluate more accurately by using maturated rats of the same age.

Animals↗
PubMedDate not supplied

Advanced solid-state carbon-13 nuclear magnetic resonance spectroscopic studies of sewage sludge organic matter: detection of organic "domains".

Two novel solid-state 13C nuclear magnetic resonance (NMR) spectroscopic techniques, PSRE (proton spin relaxation editing) and RESTORE [Restoration of Spectra via T(CH) and T(1rho)H (T One Rho H) Editing], were used to provide detailed chemical characterization of the organic matter from six Australian sewage sludges. These methods were used to probe the submicrometer heterogeneity of sludge organic matter, and identify and quantify spatially distinct components. Analysis of the T1H relaxation behavior of the sludges indicated that each sludge contained two types of organic domains. Carbon-13 PSRE NMR subspectra were generated to determine the chemical nature of these domains. The rapidly relaxing component of each sludge was rich in protein and alkyl carbon, and was identified as dead bacterial material. The slowly relaxing component of each sludge was rich in carbohydrate and lignin structures, and was identified as partly degraded plant material. The bacterial domains were shown, using the RESTORE technique, to also have characteristically rapid T(1rho)H relaxation rates. This rapid T(1rho)H relaxation was identified as the main cause of underrepresentation of these domains in standard 13C cross polarization (CP) NMR spectra of sludges. The heterogeneous nature of sewage sludge organic matter has implications for land application of sewage sludge, since the two components are likely to have different capacities for sorbing organic and inorganic toxicants present in sewage sludge, and will decompose at different rates.

Bacteria↗
PubMed2005

A new way to use solid-state carbon-13 nuclear magnetic resonance spectroscopy to study the sorption of organic compounds to soil organic matter.

Several solid-state 13C nuclear magnetic resonance (NMR) techniques were used to characterize soil organic matter spiked with 13C-labeled organic compounds spanning a range of hydrophobicities (benzoic acid, benzophenone, naphthalene, phenanthrene, and palmitic acid). The chemical shifts of NMR resonances of the sorbed species were shifted by up to 3 ppm relative to those of the neat compounds. Sorption also resulted in increased resonance linewidth for the compounds containing a single 13C label, indicating the presence of a range of different chemical environments at the sites of sorption. On the other hand, sorption decreased the linewidth of the resonance of naphthalene, which was uniformly 13C-labeled. This was attributed to the removal of intermolecular 13C-13C dipolar coupling. Heterogeneity of the organic matter was demonstrated using the spectral editing technique proton spin relaxation editing (PSRE), which enabled the identification and quantification of charcoal-rich domains characterized by rapid rates of proton spin-lattice relaxation in the static frame (T1H), and humic domains characterized by slow rates of T1H relaxation. Furthermore it was demonstrated that the sorbed 13C-labeled molecules "inherit" the T1H "signature" of the organic matrix in their immediate vicinity. Thus PSRE on the spiked soils enabled evaluation of the relative affinity of the two domain types for the sorbate molecules. The charcoal-rich domains were shown to have a twofold to tenfold greater affinity for the organic compounds, with greater differences found for the more hydrophobic compounds.

Adsorption↗
PubMed2004

A non-invasive approach to detecting organ rejection by MRI: monitoring the accumulation of immune cells at the transplanted organ.

Organ transplantation is the generally preferred medical procedure of treatment for patients with end-stage organ failure. The immunological reaction of rejection is a major cause of functional failure in transplant patients. The current "gold standard" for detecting or confirming graft rejection following solid organ transplantation requires biopsy samples in order to detect immune cell (e.g., T-cells, macrophages, etc.) infiltration into the graft and other pathological changes. This procedure is not only invasive, having associated risks, but is also prone to sampling errors that can yield false negative results. To circumvent the need for biopsies, we are developing magnetic resonance imaging (MRI) techniques to monitor the accumulation of immune cells at the transplanted organ as a means to detect graft rejection. By labeling immune cells with an MRI contrast agent, dextran-coated ultrasmall superparamagnetic iron oxide (USPIO) particles, we can monitor the accumulation of these labeled immune cells at the rejecting graft as a non-invasive method to detect graft rejection. Cells can be labeled ex vivo and then infused into the animal, or MRI contrast agents can be introduced directly into the animal in vivo. Our results show excellent correlation among the MRI signal intensity due to the USPIO-labeled macrophages at the rejecting graft, immuno-staining for macrophages, histo-pathology for graft rejection, and the iron staining of tissue samples. In this article, we shall give a summary of our progress from detecting single immune cells in vitro to monitoring the accumulation of immune cells in vivo at the transplanted kidneys, hearts, and lungs in our rat models for organ transplantation by MRI.

Animals↗
PubMed1999

Acquired organ system derangements and hospital mortality: are all organ systems created equally?

BACKGROUND: Acquired organ system derangements are common among patients who require intensive care, but the relative importance of different derangements as determinants of patients' outcomes is unclear. OBJECTIVES: To determine organ system derangements that occur in patients who require intensive care and the relative importance of different derangements to hospital mortality. METHODS: A prospective cohort study design was used to evaluate the occurrence of organ system derangements and hospital mortality in 617 adults admitted to the medical and surgical intensive care units of a university-affiliated teaching hospital. RESULTS: Eighty-three patients (13.5%) died while hospitalized. Patients who died had significantly more derangements than did patients who survived (3.3 +/- 1.2 vs 0.9 +/- 0.9; P < .001). The crude hospital mortality rate varied with the specific organ system involved (pulmonary, 23.6%; gastrointestinal, 25.0%; hepatic, 42.4%; hematological, 47.9%; cardiac, 54.0%; renal, 54.8%; neurological, 65.9%). Derangements of neurological function (adjusted odds ratio, 3.20; 95% CI, 2.0-5.3; P = .019) and cardiac function (adjusted odds ratio, 3.96; 95% CI, 2.63-5.99; P < .001) were independently associated with hospital mortality. Additionally, derangements occurred later during the stay in the intensive care unit in patients who died in the hospital than in patients who survived, especially for derangements of pulmonary, neurological, and renal function. CONCLUSION: Among critically ill patients, neurological and cardiac dysfunction are the acquired organ system derangements most closely associated with hospital mortality. These data suggest that hospital mortality depends on both the specific types of derangements that occur and the total number of such derangements. Interventions to prevent cardiac and neurological dysfunction have the greatest potential for improving outcomes for patients in the intensive care unit.

APACHE↗
PubMed2000

Early tumor growth in metastatic organs influenced by the microenvironment is an important factor which provides organ specificity of colon cancer metastasis.

We have previously demonstrated that liver metastases in nude mice and lung metastases in nude rats occurred specifically, when KM12SM human colon carcinoma cells were inoculated orthotopically into the cecal wall of nude mice and rats. To clarify the relationship between the tumor growth potential in the metastatic organs and the metastatic organ preference in these two metastatic models, we have evaluated the in vitro cell growth activities affected by the organ conditioned medium (CM) from the liver and lung, and the in vivo growth activities of the ectopic implanted tumors in the liver and lung. The tumorigenicity of the ectopic implanted tumors was 100% in mouse liver, 33% in rat liver, 50% in mouse lung, and 75% in rat lung. The crude liver CM of the animals showed inhibitory activities for KM12SM cell growth in a dosage-dependent manner, and the crude lung CM stimulated KM12SM cell growth. The liver CM of nude mice inhibited the KM12SM cell growth more strongly compared with the CM of nude rats, and the lung CM of nude rats was more strongly stimulated compared with the CM of nude mice. The liver CM of nude mice had non-heparin binding factors, which stimulated or inhibited KM12SM cell growth, in a molecular weight range of 50 to 100 kDa. By contrast, the liver CM of nude rats showed no growth stimulating activity for KM12SM cells. These results suggest that the metastatic organ specificity of KM12SM cells may depend on the early tumor growth influenced by the microenvironment in metastatic organs.

Animals↗
PubMed1998

Issues in organ procurement: presumed consent, bioethical type II errors, and organ registries.

In an effort to alleviate the current imbalance between the many in need of an organ transplant and the limited number of organs procured, a policy of presumed consent has been recently debated. Presumed consent assumes that potential organ donors agree to donate their organs in the absence of known objections to the contrary. The authors examine the bioethical principles and consequences involved in such a policy and apply hypothesis testing, borrowed from clinical epidemiology, to a "bioethical test" of presumed consent in a hypothetical clinical scenario. A possible bioethical alternative to presumed consent, an organ donor registry of advanced directives as has been established in British Columbia, is also discussed.

Advance Directives↗
PubMed1992

[Organ donation from recently deceased patients. Experiences from a donor hospital and suggestions for handling potential organ donors and their relatives].

Homologous organ transplantation using organs from patients suffering complete destruction of the brain and brain stem is a major achievement in modern medicine. The care of potential organ donors and their relatives is complex and very demanding for the medical team and nursing staff. In Norway the law sets very clear criteria (documentation of total irreversible brain and brain stem injury) for performing donation. As a rule consent from the family is asked for, although not legally required. This article deals with the problems related to the treatment of potential organ donors. We give practical guidelines for medical staff on how to prepare the patient and his/her family, with emphasis on the human and psychosocial aspects. Preservation of the donor and the organs is not discussed.

Decision Making↗
PubMed2006

[Organ transplantation using organs taken from executed prisoners in China--a call for the cessation of Israeli participation in the process].

Organ transplantation using organs taken from prisoners convicted to death is being practiced in China for the last two decades. These transplantations, which harshly violate medical ethics and international conventions, have become a prosperous market in China. This review presents details of the testimonies of a former prisoner and a Chinese physician who fled to the U.S.A., portraying the horrifying process of organ harvesting from executed prisoners, sometimes even before they are even dead. For years the Chinese authorities have denied the existence of this process, but following massive international diplomatic pressure they have recently publicly admitted to it for the first time. Many Israeli transplant candidates, who are desperate due to the organ shortage in Israel, seek their way to China in attempts to try and save their lives. The fact that they are currently being funded by all medical insurance companies constitutes a sort of formal approval to this atrocity. We, as a society, should stop this funding immediately, and divert all our human and financial resources to increase organ donation from brain-dead donors in Israel.

Attitude to Health↗
PubMed1985

Observations on organized areas of the endoplasmic reticulum, mitochondria, and ribosomes in ependymal cells of the subcommissural organ of Cebus, Saimiri and Callicebus (Platyrrhina, Primates).

The endoplasmic reticulum, the distribution of ribosomes attached to its membranes and the topographic relation of mitochondria have been studied in ependymal cells of the subcommissural organ of Cebus, Saimiri, and Callicebus. Occasionally, these organelles appear to be distinctly organized in restricted areas. They may be either irregularly arranged, formed into stacks, or organized into individualized corpuscules. The constituents of these organized areas are the same. Topographic relations with the GOLGI apparatus which would indicate a close interaction between these organelles, were not observed. The assemblage of substructures known to be involved in the synthesis of secretions of the subcommissural organ indicates a specific function of those areas.

Animals↗
PubMed1980

Chemically-defined organ culture of embryonic mouse tooth organs: morphogenesis, dentinogenesis and amelogenesis.

Chemically-defined in vitro conditions without serum have been identified which are permissive for embryonic mouse tooth organs to express morphogenesis and cytodifferentiation. In the absence of antibiotics, embryonic extracts, autologous and/or heterologous sera, molar tooth organs from Theiler stage 25 embryos (C57BL/6, A/Jax and Tabby mouse strains) routinely formed discrete dentin and enamel extracellular organic matrices within 10 days of continuous in vitro cultivation. Collagen and non-collagenous protein synthesis and secretion by differentiated cells within explants, between 9 and 10 days in vitro, were studied with light microscopic autoradiography. Finally, explants of embryonic mouse molar tooth organs have been maintained in organ culture for three week without serum supplementation.

Amelogenesis↗
PubMed1997

[Which graft for which patient? and when? III. Organization schema of organ procurement and graft coordination].

Organ and tissue procurement strongly increased during the past decades to become a common activity among accredited hospitals. Structuring efficient regional organ procurement organisations appear as an important goal in order to offer the relevant number and quality of transplants to the patients on the national waiting list maintained by the Etablissement français des Greffes. Two structures acting together coordinate organ and tissue procurement: (i)accredited hospitals allocate some medical and non medical personal interfacing; (ii) the Etablissement français des Greffes through one of its seven regional units or its national unit. These units are in charge with the operational responsibility of multiorgan and tissue retrieval co-ordination in their geographical area, with organ allocation and with an institutional role of local and regional organ procurement development and promotion.

France↗
PubMed2004

Mutation of amino acid 475 of rat organic cation transporter 2 (rOCT2) impairs organic cation transport.

Protein sequence alignments revealed one amino acid position, where organic cation transporters (OCTs, aspartate (D) at position 475 of rOCT2) and organic anion transporters (OATs, arginine (R) at position 466 of rOAT1) are charged oppositely. To address the impact of this amino acid for protein function we cloned rat organic cation transporter 2 (rOCT2), the renal electrogenic cation transporter of the basolateral side of proximal tubule cells. Site-directed mutagenesis was used to generate rOCT2-D475R (rOCT2-mut). Heterologous expression of rOCT2 wild-type (rOCT2-wt) in A6 cells resulted in a significant uptake of the fluorescent organic cation 4-(4-dimethylaminostyryl)-N-methylpyridinium (ASP(+)). Accordingly, rOCT2-wt-transfected COS 7 cells showed an almost fourfold uptake of 25 microM [(14)C]-TEA, whereas rOCT2-mut did not exhibit any uptake of [(14)C]-TEA. These data indicate that rOCT2 transports both ASP(+) and TEA and that aspartate at position 475 of rOCT2 plays a critical role in transport function.

Amino Acid Substitution↗
PubMed2005

Sex differences in the mRNA, protein, and functional expression of organic anion transporter (Oat) 1, Oat3, and organic cation transporter (Oct) 2 in rabbit renal proximal tubules.

Sex differences in transport of the organic anion (OA) substrate p-aminohippurate (PAH) and the organic cation (OC) substrate tetraethylammonium (TEA) have been recognized for some time. In the rat kidney, androgens up-regulate and estrogens down-regulate PAH and TEA transport, which correlate with similar changes in mRNA and protein expression for the renal basolateral membrane transporters organic anion transporter (Oat) 1 and organic cation transporter (Oct) 2. However, these sex differences are not readily demonstrated in other species. The present study characterizes the kinetics of basolateral membrane PAH, estrone sulfate (ES), and TEA uptake in renal proximal tubule (RPT) suspensions isolated from female and male rabbits to compare functional expression of transport with mRNA and protein expression for rbOat1, rbOat3, and rbOct2. Although rbOat1-rbOat3 mRNA expression exhibited developmental differences, no sex differences in mRNA levels were observed. Oat1 and Oat3 protein expression in RPT suspensions also was similar between adult female and male rabbits. In contrast, rbOct1 and rbOct2 mRNA levels did not show developmental differences, but rbOct2 mRNA expression was greater in adult male than female rabbits. However, the sex difference in rbOct2 mRNA level did not translate to rbOct2 protein expression. Importantly, functional expression of Oat1, Oat3, and Oct2 transport as measured by kinetics (J(max) and K(t)) of PAH, ES, and TEA uptake was similar between adult male and female rabbits, and correlated with rbOat1, rbOat3, and rbOct2 protein expression. Thus, unlike rodents, rabbit renal OA and OC transport does not exhibit sex differences, pointing to the need for caution in extrapolating transport-related sex differences between species.

Animals↗
PubMed1975

Histological and three dimensional organization of the odontogenic organ in the upper incisor of 100 gm rats: comparison with the lower incisor.

The epithelial tissue forming the posterior aspect of the apical foramen in the upper incisor of the rat was reconstructed from 1 mum thick serial cross sections. Like the lower incisor, this portion of the odontogenic organ in the upper incisor was composed of a bulbous and a "U"-shaped part. However, the bulbous part was considerably blunter and the "U"-shaped part much larger in circumference in comparison to the lower incisor. Although no differences were found between the upper and lower incisor regarding the contents and the basic organization of cells within each part of the odontogenic organ, specific differences were found within the bulbous part in the upper incisor. There was a more definitive boundary between the outer dental epithelium and stellate reticulum, a more intimate relationship of cell streams to the stellate reticulum, and a noticeable lack of swirling of cells as part of the streams. These features suggest that the activity inside the bulbous part is less intense in the upper incisor than it is in the lower incisor. In addition, the relationships between the bulbous part, the "U"-shaped part and the root sheath part of the odontogenic organ and the enamel organ were described for the upper incisor.

Ameloblasts↗
PubMed2006

Chicken lateral septal organ and other circumventricular organs form in a striatal subdomain abutting the molecular striatopallidal border.

The avian lateral septal organ (LSO) is a telencephalic circumventricular specialization with liquor-contacting neurons (Kuenzel and van Tienhoven [1982] J. Comp. Neurol. 206:293-313). We studied the topological position of the chicken LSO relative to molecular borders defined previously within the telencephalic subpallium (Puelles et al. [2000] J. Comp. Neurol. 424:409-438). Differential expression of Dlx5 and Nkx2.1 homeobox genes, or the Shh gene encoding a secreted morphogen, allows distinction of striatal, pallidal, and preoptic subpallial sectors. The chicken LSO complex was characterized chemoarchitectonically from embryonic to posthatching stages, by using immunohistochemistry for calbindin, tyrosine hydroxylase, NKX2.1, and BEN proteins and in situ hybridization for Nkx2.1, Nkx2.2, Nkx6.1, Shh, and Dlx5 mRNA. Medial and lateral parts of LSO appear, respectively, at the striatal part of the septum and adjacent bottom of the lateral ventricle (accumbens), in lateral continuity with another circumventricular organ that forms along a thin subregion of the entire striatum, abutting the molecular striatopallidal boundary; we called this the "striatopallidal organ" (SPO). The SPO displays associated distal periventricular cells, which are lacking in the LSO. Moreover, the SPO is continuous caudomedially with a thin, linear ependymal specialization found around the extended amygdala and preoptic areas. This differs from SPO and LSO in some molecular aspects. We tentatively identified this structure as being composed of an "extended amygdala organ" (EAO) and a "preoptohypothalamic organ" (PHO). The position of LSO, SPO, EAO, and PHO within a linear Dlx5-expressing ventricular domain that surrounds the Nkx2.1-expressing pallidopreoptic domain provides an unexpected insight into possible common and differential causal mechanisms underlying their formation.

Animals↗
PubMed1988

Organization of spinocerebellar projection map in three types of agranular cerebellum: Purkinje cells vs. granule cells as organizer element.

The organization of the spinocerebellar projection was analysed by the anterograde axonal WGA-HRP (horseradish peroxidase-wheat germ agglutinin conjugate) tracing method in three different types of agranular cerebellar cortex either induced experimentally by X-irradiation or occurring spontaneously in weaver (wv/wv) and staggerer (sg/sg) mutant mice. The results of this study show that in the X-irradiated rat and weaver mouse, in both of which the granule cells are directly affected and die early in development, the spinal axons reproduce, with few differences, the normal spinocerebellar pattern. Conversely, in staggerer mouse, in which the Purkinje cells are intrinsically affected and granule neurons do not seem to be primarily perturbed by the staggerer gene action, the spinocerebellar organization is severely modified. These findings appear somewhat paradoxical because if granule cells, the synaptic targets of mossy spinocerebellar fibers, were necessary for the organization of spinocerebellar projection, the staggerer cerebellum would exhibit a much more normal projectional map than the weaver and the X-irradiated cerebella. It is, therefore, obvious that granule cells, and even specific synaptogenesis, are not essential for the establishment of the normal spinocerebellar topography. On the other hand, the fact that the Purkinje cells are primarily affected in the unique agranular cortex in which the spinocerebellar organization is severely modified suggests that these neurons could be the main element in the organization of the spinocerebellar projection map. This hypothesis is discussed in correlation with already-reported findings on the zonation of the cerebellar cortex by biochemically different clusters of Purkinje cells.

Animals↗
PubMed1989

Organic acid (or anion) and organic base (or cation) transport by renal tubules of nonmammalian vertebrates.

Organic acids (or anions) and organic bases (or cations) are transported by the renal tubules of nonmammalian vertebrates, but until recently the details of the transport processes have been poorly studied. Work with isolated perfused and nonperfused renal tubules and with membrane vesicles has now begun to supply information on the transepithelial transport processes and the transport steps at the individual cell membranes. The current information is reviewed for organic acids (or anions) as a general group, for urate (which generally appears to be transported by a separate system from that for other organic anions), and for organic bases (or cations) as a general group. Tentative cellular models for the transepithelial transport of each of these general categories of compounds are suggested.

Amphibians↗