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Biomedical subjects

J Blue

Publications and source records attributed to J Blue.

27 records · Page 2Linked to original sources
PubMed1985

Urinary tract infection due to indwelling bladder catheters in dogs and cats.

Urine samples were collected from 27 dogs and 4 cats with indwelling urinary catheters connected to a closed system. Twenty-one animals had sterile urine at the initiation of catheterization. Eleven of these 21 animals developed positive urine culture after 4 (mean) days (range 1 to 10 days) of catheterization. Infections persisted after catheter removal in 6 of 8 animals. The 10 animals that did not develop bacteriuria had a shorter duration of catheterization (3 days vs 12 days, mean). Antibiotics (chloramphenicol, trimethoprim/sulfonamide, cephradine, lincomycin, gentamicin, or ampicillin) were used during the period of catheterization in 17 of 21 animals, 8 of which developed bacteriuria and 9 of which did not. Ten animals had bacteriuria at the initiation of urine collection for culture. The type of bacteria changed during the catheterization period in 6 animals, all of which were given antibiotics. Bacteria isolated from animals given antibiotics seemed to become increasingly antibiotic-resistant.

Animals↗
PubMed1985

Behavior problems and social competence in girls with true precocious puberty.

We report a controlled standardized behavioral assessment of 33 girls with true precocious puberty using the Child Behavior Checklist. Although a majority of the girls were reported not to have behavior problems, many were reported to have a dysphoric adjustment to their condition. Twenty-seven percent of the girls with true precocious puberty scored greater than 2 SD above the mean on the Total Behavior Problem scale 10 times the expected prevalence rate. They also scored significantly higher (P less than 0.01) than matched controls on both the internalizing or "overcontrolled symptom" and externalizing or "undercontrolled symptom" scales. Forty-eight percent scored greater than 2 SD above the mean on the Social Withdrawal scale. The high prevalence of reported problem behaviors in this sample may be related directly or indirectly to the precocious maturation mediated by biologic, psychologic, social, and environmental variables. Although elevated levels of sex steroids may directly contribute to increased aggressive and hyperactive behaviors, they may also be modified by social and environmental factors.

Adaptation, Psychological↗
PubMed1985

Biological considerations for treating alternate fields versus all fields daily with high and low LET radiation.

The rationale for treating all fields every day with photons was reviewed. Since the effects of neutron radiation are much less dependent on alterations of fractionation schedules, and since preferential sparing for late effects is not obtained by fractionation of neutron dose, less convincing reasons exist for treating all fields every day with neutrons. Treating one field/day would not alter the physical dose distribution or overall treatment time, yet still maintain biological homogeneity. Preliminary in vitro experiments support this conclusion.

Animals↗
PubMed1981

Periarterial macrophage sheaths (ellipsoids) in cat spleen--an electron microscope study.

Periarterial macrophage sheaths (PAMS), a term we introduce to replace "ellipsoids," surround arterial capillaries in the red pulp of the spleen and are major sites for clearance of blood-borne particles. PAMS and their arterial capillaries in cat spleens in various states of congestion and contraction were studied by transmission electron microscopy. Thorotrast, a colloidal suspension of thorium dioxide, was injected to label macrophages. A PAMS consisted of a fine meshwork of reticular cells and reticular fibers which held macrophages and formed a cylindrical sheath around an arterial capillary lying in its longitudinal axis. Some PAMS were spongy due to loosening of cell associations by plasma infiltration; others were tightly compressed. Blood cells were both free in the interstices of the PAMS and attached to macrophages. Reticular cells formed a closely applied but incomplete layer adventitial to the arterial capillary and extended branches which contributed to the meshwork. Small villous processes on the major branches of reticular cells approached each other, sometimes forming intercellular junctions, and fit into complementary indentations in the surfaces of macrophages and endothelial cells. Thin filaments within reticular cells filled the villous processes and formed a border beneath the plasmalemma; intermediate filaments ran through the centers of the branches. Reticular fibers lay between reticular cells. Basement membrane fabricated of the same material as reticular fibers lay between the endothelium and reticular cells. Macrophages contained Thorotrast and abundant debris of phagocytized cells and were joined by extensive interdigitation of micropseudopodia. Endothelial cells were long rods which lay parallel and were joined along their bases by interdigitating lateral processes. Intercellular junctions were present at some points, but at others lateral processes were everted to form open interendothelial slits through which blood cells could pass. Endothelial cells possessed great numbers of randomly oriented intermediate filaments and small patches of thin filaments scattered along the basal plasmalemma and in lateral processes. Thin filaments may function to attach cells to one another and to the basement membrane and may assist in closing interendothelial slits. We believe that the endothelium responds to changes in arterial blood pressure and blood flow. It stretches to allow dilatation and recoils, probably due to the intermediate filaments, squeezing blood cells through interendothelial slits.

Animals↗
PubMed1981

Vascular pathways in nonsinusal red pulp--an electron microscope study of the cat spleen.

The red pulp of the cat spleen, including terminal segments of arterial capillaries, pulp venules, and the reticular meshwork, was studied by transmission electron microscopy. Splenic congestion and contraction were produced by barbiturate anesthetic and norepinephrine. Terminal segments of arterial capillaries were ampullary and flared. Blood escaped into surrounding pulp spaces through interendothelial gaps. Pulp venules originated as open-ended vessels in the reticular meshwork near trabeculae and drained into trabecular veins. Venule walls were thin and composed of squamous endothelial cells, a continuous basement membrane, and reticular cells. Venules in congested spleens had many mural apertures, but venules in contracted spleens had few. The interstices of the reticular meshwork in congested spleens contained large amounts of blood, which often was concentrated, many macrophages, lymphocytes, and plasma cells. Fewer blood cells and scant plasma were present in contracted spleens. The vascular arrangements are anatomically open. Blood takes pathways through the reticular meshwork from arterial terminations to pulp venules. Some pathways through the reticular meshwork probably function as closed vascular channels conveying rapidly flowing blood. Other pathways are functionally open and probably contain slowly moving blood that constitutes a reservoir of red cells. Macrophages formed associations with mature red cells and with reticulocytes. Mature red cells were attached to macrophages in a manner indicating erythrophagocytosis. Reticulocyte attachment had a different appearance and likely resulted in reticulocyte sequestration. Platelets bore pseudopodia which would impede their passage through irregular and cell-filled pulp spaces. The change in platelet shape probably is responsible for the formation of the splenic pool of platelets.

Animals↗
PubMed1981

Species variation in the structure and function of the marginal zone--an electron microscope study of cat spleen.

The marginal zone in the cat spleen consisted of a characteristic mixture of lymphocytes and other blood cells located mainly between the several layers of circumferential reticulum around white pulp. A region of fine-meshed reticulum between white pulp and red pulp, as present in some species, was absent from the cat spleen. Arterial capillaries to the marginal zone were few. Some were continuations of white pulp capillaries, whereas others were red pulp capillaries that likely were continuations of axial capillaries of periarterial macrophage sheaths (PAMS) (ellipsoids). Blood cells deposited in the marginal zone could reach red pulp by passing through the numerous openings in each layer of circumferential reticulum. Lymphocytes appeared to migrate across the marginal zone both toward and away from white pulp. Macrophages lying on the circumferential reticulum of the marginal zone phagocytized cells but did not ingest Thorotrast, although it coated their surfaces. Because of the scarcity of arterial endings and the lack of a macrophage-charged reticular meshwork, the marginal zone in cat spleen is not a major site of blood clearance and phagocytosis. These functions are better served in PAMS and red pulp.

Animals↗
PubMed1981

Electron microscopy of the red pulp of the dog spleen including vascular arrangements, periarterial macrophage sheaths (ellipsoids), and the contractile, innervated reticular meshwork.

The vascular and stromal arrangements of the red pulp in congested and contracted dog spleens were studied by transmission electron microscopy. Each dog had been injected intravenously with Thorotrast to label actively endocytizing cells. Only macrophages ingested Thorotrast. The proximal portion of each arterial capillary was surrounded by a "periarterial macrophage sheath" (PAMS), a term we introduce to replace the term "ellipsoid". PAMS were composed of a fine meshwork of reticular cells and reticular fibers which held tightly-packed macrophages and interspersed blood cells. These macrophages, as well as those in the reticular meshwork of red pulp, contained Thorotrast, cell debris, and deposits of hemosiderin. The arterial capillary at the center of each PAMS was formed by parallel, rod-shaped endothelial cells and discontinuous layers of basement membrane and reticular-cell cytoplasm. PAMS were tapered at their distal ends; the terminal portion of the arterial capillary continued beyond the PAMS to end in the reticular meshwork of red pulp. Endothelial cells in the terminal arterial capillaries were separated by gaps through which blood cells passed into the spaces of the reticular meshwork of red pulp. The reticular meshwork was formed by reticular cells which appeared to be specialized for contraction. These cells were filled with thin filaments and possessed plasmalemmal dense bodies as found in smooth muscle cells. Furthermore, the reticular meshwork was innervated by unmyelinated adrenergic axons which probably were derived from nerves that followed arterioles. Axons were enclosed in surface invaginations of cells which were similar to reticular cells in shape and cytologic detail and which we called "axon-bearing reticular cells". Axon-bearing reticular cells were inserted between the branches of the reticular cells that formed the meshwork. Venous sinuses formed an anastomosing system of vessels draining into pulp veins which then joined trabecular veins. Sinuses were formed by parallel, rod-shaped endothelial cells encircled by strands of basement membrane and reticular-cell branches. Endothelial cells lay closely side by side except where interendothelial slits were opened by blood cells passing into the lumen or by pseudopodia of macrophages which lay outside the sinus. Cell traffic across the sinus wall was greatest in areas where blood cells were mixed with plasma. Congested spleens stored concentrated red cells in both sinuses and the reticular meshwork; contracted spleens were emptied of blood. The reticular meshwork may contract to assist trabecular and capsular smooth muscle in expelling stored red cells and effecting hemoconcentration.

Animals↗
PubMedDate not supplied

Interaction between exercising humans and growing plants in a Closed Ecological Life Support System.

The purpose of this study was to quantify the gas exchange between plants growing in a Closed Environmental Life Support System (CELSS) and the metabolism of human subjects undergoing various levels of physical exercise, and subsequently determine the buffer characteristics in relation to the carbon exchange established for plants in this closed loop life support system. Two men (ages 42 and 45 yr) exercised on a cycle ergometer at three different work intensities, each on a separate day. The CELSS, a 113 m3 chamber, was sized to meet the needs of one human. The plants, consisting of 20 m2 of potato, provided oxygen to the human during an artificially lighted photosynthesis phase and the human provided CO2 to the plants. The average rates of exchange for the subjects were 0.88, 1.69, and 2.47 liters O2/min and 0.77, 1.47, and 2.21 liters CO2/min at approximately 25%, 50%, and 75% of their maximal aerobic capacity, respectively. The photosynthetic rate for the CELSS was 0.95 liters/min. A balance between human CO2 production and plant utilization was noted at approximately the 50% VO2max level. The oxygen balance and changes were not within detectable limits of the CELSS instrumentation for the durations of these exercise exposures. If a CELSS environment is the methodology selected for long term spaceflight, it will be important to select plants that efficiently grow at the available light and nutrient levels while balancing the needs for the human crew at their levels of physical activity.

Adult↗