Veins central

Bird, B. C., and Darling, R. S. (1996). Fluid Inclusion Study of the Long Lake Calcite-Fluorite Vein, Central Adirondacks. Geol. Soc. Am., Abs. 28(3), 38 pp. 

Long-lasting vasoconstriction is produced by the ETs in almost all arteries and veins and several studies have shown that ET-1 causes a reduction in renal blood flow and urinary sodium excretion. ET-1 has been reported to be a potent mitogen in fibroblasts and aortic smooth muscle cells and to cause contraction of rat stomach strips, rat colon and guinea pig ileum. In the central nervous system, ETs have been shown to modulate neurotransmitter release. 

Almost two-thirds of the world s copper resources are porphyry deposits. The term porphyry is generally appUed to a type of disseminated copper deposit that is hydrothermal in origin and characterized by a large proportion of minerals uniformly distributed as disseminations or in fractures and small veins. Copper contents are generally 1% or less. The most extensive porphyry deposits are located in western Canada, the southwestern United States, Mexico, and western South America. In addition to the porphyrys, there are large bedded copper deposits in Germany, Poland, the CIS, AustraUa, and central Africa. 

TPN may be administered through a peripheral vein or through a central venous catheter. Peripheral TPN is used for patients requiring parenteral nutrition for relatively short periods of time (no more than 5-14 days) and when the central venous route is not possible or necessary. Peripheral TPN is used when the patient s caloric needs are minimal and can be partially met by normal... 

Intoxicated patients surviving for 28 hours to 9 days had hepatocytes free in central or hepatic veins this finding was described as mobilization of liver cells. The role of methyl parathion in the induction of all of these lesions is unclear. 

M (more severe necrosis inflammation, dilation, and congestion of central veins and sinusoids)... 

The ammonia produced by enteric bacteria and absorbed into portal venous blood and the ammonia produced by tissues are rapidly removed from circulation by the liver and converted to urea. Only traces (10—20 Ig/dL) thus normally are present in peripheral blood. This is essential, since ammonia is toxic to the central nervous system. Should portal blood bypass the liver, systemic blood ammonia levels may rise to toxic levels. This occurs in severely impaired hepatic function or the development of collateral links between the portal and systemic veins in cirrhosis. Symptoms of ammonia intoxication include tremor, slurred speech, blurred vision, coma, and ultimately death. Ammonia may be toxic to the brain in part because it reacts with a-ketoglutarate to form glutamate. The resulting depleted levels of a-ketoglutarate then impair function of the tricarboxylic acid (TCA) cycle in neurons. 

Parenteral Fluids. During the past ten years interest has been renewed in the total alimentation of the infant by vein (2). The motivation for this is the fact that neonates may suffer from some congenital malformation of the intestinal tract which would require surgical resection. If this is done, then one needs some outside way for alimentation, bypassing the intestine, until the intestine is able to heal and recover its normal function. This may take many weeks. A second source of motivation is the small premature infant weighing less than a kilogram, whose immature central nervous system and gastrointestinal tract make it difficult to establish nutrition by oral intake soon after birth. These also require total intravenous nutrition for a substantial period of time. 

Polymetallic vein-type deposits occur in middle Miocene volcanic terrain in central and western Japan. 

Figure 1.104. The relationship among S O (in permil) of fluids, minor element contents, and A/Q (adula-ria/quartz ratio) in the vein from wall rock side (3-IT) to central part (5-2T) (Ryosen No. 5 vein, Hishikari mine, 85 ml E50) (Shikazono and Nagayama, 1993).

The vein-type deposits can be divided into two based on the metals produced precious (Au, Ag) and base metal (Pb, Zn, Ag, Mn, Cu, Fe) vein-types. There are two sub-types of the base metal vein-type deposits, the Cu-Pb-Zn sub-type and the Pb- Zn-Mn-Ag sub-type. Cu-Pb-Zn veins occur in southern part of the province. Large Pb-Zn-Mn-Ag veins and Au-Ag veins are distributed in northeastern part. In the northeastern part, Au-Ag vein-type deposits occur in marginal zones of the province, while the base metal-rich deposits (Pb-Zn-Mn veins and Kuroko deposits) in central zone (Fig. 1.149). The marginal zone is characterized by exposure of Quaternary volcanic rocks and Plio-Pleistocene volcanic rocks in which Au-Ag veins occur, whereas the central zone is by thick submarine volcanic rocks (Fig. 1.150), in which base metal-rich deposits (base metal veins and Kuroko deposits) occur (Fig. 1.150). Tertiary volcanic rocks, Quaternary volcanic rocks and faults are distributed, trending generally from NW to SE. Some Cu-Pb-Zn veins in southern part are hosted by basement rocks. On the other hand, Pb-Zn-Mn-Ag and Au-Ag veins occur in Tertiary and Quaternary volcanic rocks. 

It is inferred that in the northern part of the province submarine volcanic rocks are thick in the central zone, while at marginal zone it is thin and the Plio-Pleistocene subaerial volcanic rocks are exposed. The vein-type deposits occur widely in the province. The precious vein-type deposits occur in relatively young (Plio-Pleistocene) volcanic rocks, while large base metal vein-type deposits (e.g., Toyoha, Inakuraishi, Ohe) and Kuroko deposits (e.g., Kunitomi) occur in central zone where thick Miocene submarine volcanic rocks are distributed (Figs. 1.149 and 1.150). Small base metal vein-type deposits occur in Paleozoic rocks in the southern part. 

It is generally accepted that Kuroko deposits formed under the submarine environment, while polymetallic vein-type deposits in central and Northwest Japan (Ashio, Tsugu, Kishu, Obira, etc.) under the subaerial environment. 

I.6.3.2. Gold-quartz vein-type deposits in Yamizo Mountains, central Japan... 

The Yamizo Mountains extend over the eastern part of Tochigi Prefecture, and the western part of Ibaragi Prefecture, central Japan, occupying an area ca. 20 km by 50 km. A lot of hypo/mesothermal (in the sense of Lindgren, 1933) gold vein-type deposits exist there (Fig. 1.191). 

Kamilli, R.J. and Ohmoto, H. (1977) Paragenesis, zoning, fluid inclusion, and isotope studies of the Finlandia vein, Colqui district, central Peru. Econ. Geol., 72, 950—982. 

Kase, K. (1988) Tin, arsenic, zinc and silver vein mineralization in the Besshi mine. Central Shikoku, Japan. Mining Geology, 38, 407-418. 

Figure 39.4a represents schematically the intravenous administration of a dose D into a central compartment from which the amount of drug Xp is eliminated with a transfer constant kp. (The subscript p refers to plasma, which is most often used as the central compartment and which exchanges a substance with all other compartments.) We assume that mixing with blood of the dose D, which is rapidly injected into a vein, is almost instantaneous. By taking blood samples at regular time intervals one can determine the time course of the plasma concentration Cp in the central compartment. This is also illustrated in Fig. 39.4b. The initial concentration Cp(0) at the time of injection can be determined by extrapolation (as will be indicated below). The elimination pool is a hypothetical compartment in which the excreted drug is collected. At any time the amount excreted must be equal to the initial dose D minus the content of the plasma compartment Xp, hence ...

Patients who require parenteral nutrition for >7 d ° Must be administered through a central vein... 

Dose of 0.3 N THAM (mL) =1.1 ([ABW in kg] x [goal HC03 - patient s HC03]) administered intravenously >1-6 h using a large peripheral vein or central vein... 

Invasive hemodynamic monitoring in patients with HF entails placement of a right heart or pulmonary artery catheter (PAC). The catheter is inserted percutaneously through a central vein and advanced through the right side of the heart to the... 

Calcium gluconate is the preferred peripherally infused calcium supplement because it is less irritating to the veins. Calcium chloride must be infused via a central line. 

Retinal or vitreous hemorrhage, retinal detachment, transient or permanent visual loss central retinal vein occlusion... 

JM is a 32-year-old woman who was recently diagnosed with stage IIIB Hodgkin s disease. She comes to the clinic to receive her first dose of ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) chemotherapy. She currently does not have a central access device therefore, she will receive her chemotherapy via peripheral vein. 

PN can be administered via a small peripheral vein [as peripheral PN (PPN)] or via a larger central vein (as central PN). 

Potassium is the second most abundant cation in the body and is found primarily in the intracellular fluid. Potassium has many important physiologic functions, including regulation of cell membrane electrical action potential (especially in the myocardium), muscular function, cellular metabolism, and glycogen and protein synthesis. Potassium in PN can be provided as chloride, acetate, and phosphate salts. One millimole of potassium phosphate provides 1.47 mEq of elemental potassium. Generally, the concentration of potassium in peripheral PN (PPN) admixtures should not exceed 80 mEq/L (80 mmol/L). While it is safer to also stick to the 80 mEq/L (80 mmol/L) limit for administration through a central vein, the maximum recommended potassium concentration for infusion via a central vein is 150 mEq/L (150 mmol/L).14 Patients with abnormal potassium losses (e.g., loop or thiazide diuretic therapy) may have higher requirements, and patients with renal failure may require potassium restriction. 

Route of PN Administration Peripheral Versus Central Vein Infusion... 

PN can be administered via a smaller peripheral vein (e.g., cephalic or basilic vein) or via a larger central vein (e.g., superior vena cava). Peripheral PN (PPN) is infused via a peripheral vein and generally is reserved for short-term administration (up to 7 days) when central venous access is not available. PN formulations are hypertonic, and infusion via a peripheral vein can cause thrombophlebitis. Factors that increase the risk of phlebitis include high solution osmolarity, extreme pH, rapid infusion rate, vein properties, catheter material, and infusion time via the same vein.20 The osmolarity of PPN admixtures should be limited to 900 mOsm/L or less to minimize the risk of phlebitis. The approximate osmolarity of a PN admixture can be calculated from the osmolarities of individual components ... 

Central PN refers to the administration of PN via a large central vein, and the catheter tip must be positioned in the vena cava. Central PN allows the infusion of a highly concentrated, hypertonic nutrient admixture. The typical osmolarity of a central PN admixture is about 1500 to 2000 mOsm/L. Central veins have much higher blood flow, and the PN admixture is diluted rapidly on infusion, so phlebitis is usually not a concern. Patients who require PN administration for longer periods of time (greater than 7 days) should receive central PN. One limitation of central PN is the need for placement of a central venous catheter and an x-ray to confirm placement of the catheter tip. Central venous catheter placement may be associated with complications, including pneumothorax, arterial injury, air embolus, venous thrombosis, infection, chylothorax, and brachial plexus injury.1,20... 

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