Medullary

Clinically, GM-CSF or G-CSF have been used to accelerate recovery after chemotherapy and total body or extended field irradiation, situations that cause neutropenia and decreased platelets, and possibly lead to fatal septic infection or diffuse hemorrhage, respectively. G-CSF and GM-CSF reproducibly decrease the period of granulocytopenia, the number of infectious episodes, and the length of hospitalization in such patients (152), although it is not clear that dose escalation of the cytotoxic agent and increased cure rate can be rehably achieved. One aspect of the effects of G-CSF and GM-CSF is that these agents can activate mature cells to function more efficiently. This may, however, also lead to the production of cytokines, such as TNF- a, that have some toxic side effects. In general, both cytokines are reasonably well tolerated. The side effect profile of G-CSF is more favorable than that of GM-CSF. Medullary bone pain is the only common toxicity. 

Wool fibers consist of cells, where battened ovedapping cuticle cells form a protective sheath around cortical cells. In some coarser fibers, a central vacuolated medullary cell type may be present. 

Fig. 2. Schematic representation of relevant electrolyte transport through the renal tubule, depicting the osmolar gradient ia medullary iaterstitial fluid ia ywOj yW where represents active transport, —passive transport, hoth active and passive transport, and passive transport of H2O ia the presence of ADH, ia A, the cortex, and B, the medulla. An osmole equals a mole of solute divided by the number of ions formed per molecule of the solute. Thus one mole of sodium chloride is equivalent to two osmoles, ie, lAfNaCl = 2 Osm NaCl. ADH = antidiuretic hormone.

In normal human subjects, ANP infusion for one hour causes increased absolute and fractional sodium excretion, urine flow, GFR, and water clearance (53—55). As shown in many in vitro and in vivo animal studies, ANP achieves this by direct effect on the sodium reabsorption in the inner medullary collecting duct, ie, by reducing vasopressin-dependent free-water and sodium reabsorption leading to diuresis and by indirect effect through increased hemodynamic force upon the kidney. ANP inhibits the release of renin and aldosterone resulting in the decreased plasma renin activity and aldosterone concentration (56,57). 

Muzolimine (710), a 1-substituted 2-pyrazolin-5-one derivative, is a highly active diuretic, differing from the structures of other diuretics since it contains neither a sulfonamide nor a carboxyl group. It has a saluretic effect similar to furosemide and acts in the proximal tubule and in the medullary portion of the ascending limb of the loop of Henle. Pharmacokinetic studies in dogs, healthy volunteers and in patients with renal insufficiency show that the compound is readily absorbed after oral administration (B-80MI40406). 

Cocaine. This lias a bitter taste, is mydriatic, produces local anaesthesia and is toxic. After absorption, or when taken internally, it acts chiefly by stimulation of the central nervous system, succeeded by depression. Since the two phases may be present in different areas simultaneously, a mixed result may ensue. With large doses the chief symptoms are those of medullary depression. Death is due to paralysis of the respiratory centre. The main use of cocaine in medicine is as a local anaesthetic. 

Mark-, medullary, markant, a. striking, remarkable, markartig, a. marrow-like, myeloid, medullary pith-like. 

Rohren-halter, m. tube (or pipe) holder, tube (or pipe) clamp, -kassie, /. pur ng cassia, -kleuune, /. tube clamp, -kiibler, m. tubular condenser, tube condenser tubular cooler, -libelle, /. spirit level, air level, -lot, n. pipe solder, -manna, /. flake manna, -nudeln, /.pi. macaroni, -ofen, m. tube furnace (for heating tubes liable to explosion) pipe still, -pulver, n. (Expl.) perforated powder, -struktur, /. tubular structure, -substanz, /. (Anat.) medullary substance, -trager, m. tube (or pipe) support, -wachs, n. petroleum ceresin. -werk, n. tubing piping tube mill, -wischer, m. tube brush, -wulst, n. tubular tore, doughnut , -zelle, /. tubular cell, specif. (Bot.) tracheid. 

Dronabinol (tetrahydrocannabinol), the active principle from cannabis and synthetic cannabinoids, nabilone and levonantradol are effective in treating nausea and vomiting in cancer chemotherapy. The mode of action is unclear but appears to involve cannabinoid CBi receptors. Cannabinoids have been shown to reduce acetylcholine release in the cortex and hippocampus, and have been suggested to inhibit medullary activity by a cortical action. Inhibition of prostaglandin synthesis and release of endorphins may also be involved in the antiemetic effect. A review of trials of dronabinol, nabilone or levonantradol concluded that while the cannabinoids were superior to placebo or dopamine receptor antagonists in controlling emesis... 

Porreca F, Ossipov MH, Gebhart GF (2002) Chronic pain and medullary descending facilitation. Trends Neurosci 25 319-325... 

Inhibition of acetylcholine stimulated medullary catecholamine release... 

The VACM-1 receptor is a membrane-associated protein with a single putative transmembrane domain that binds selectively AVP (XD — 2 nM), but cannot discriminate between VXR and V2R analogues. It is expressed in endothelial and medullary collecting duct cells and upon stimulation by AVP. It induces a mobilization of cytosolic-free Ca2+, decreases cAMP production and inhibits cellular growth via MAPK phosphorylation and p53 expression. The mechanism of action and physiological functions of this new receptor are not well understood, but it seems to participate in the regulation of AVP induced signal transduction pathways or of a yet unidentified peptide. 

Renal Effects. Hemorrhage of the medullary layer of the kidneys was reported in three persons who died following ingeshon of endosulfan (Terziev et al. 1974). Acute renal failure was a major contributor to the deaths of two individuals who ingested unknown amounts of endosulfan (Blanco-Coronado et al. 1992 Loetal. 1995). In both cases, postmortem examination revealed extensive tubular necrosis. In contrast, no kidney lesions were found in a man who died 4 days after ingesting approximately 260 mg endosulfan/kg (Boereboom et al. 1998). 

DBH is a monooxygenase and uses ascorbate as an electron donor, copper at the active site, and fiimarate as modulator. DBfl is in the particulate fraction of the medullary cells, probably in the secretion granule thus. 

Methodology. Several radioimmunoassays of human calcitonin (hCT) have been developed In the past 5 years (18-20). Their greatest utility has been In the definitive diagnosis of patients with medullary carcinoma of the thyroid gland (MTC) and, recently. In Identifying family members of these patients who have occult MTC. 

Synthetic hCT Is not commercially available now. Most assays have been developed by using hormone supplied as gifts from the CIBA-Gelgy Co., Basel, Switzerland for 131i or labeling. Immunization and standards although several useful antisera have been produced by Immunization with crude extracts of medullary carcinoma tissue. 

Hill, C. S. Jr. "Immunoassay of Human Calcitonin Clinical Measurement, Relation to Serum Calcium and Studies in Patients With Medullary Carcinoma". N. Engl. J. Med. (1970), 283. 890-895. 

L. J. Holtermuller, K. H. Arnaud, C. D. "Relations of Calcitonin and Gastrin in the Zollinger-Ellison Syndrome and Medullary Carcinoma of the Thyroid". N. Engl. J. Med. 

Sizemore, G. W. Heath, H. Ill "Immunochemical Heterogeneity of Calcitonin in Plasma of Patients With Medullary Carcinoma of the Thyroid". J. Clin. Invest. (1975), In Press. 

Early Diagnosis of Medullary Carcinoma of the Thyroid Gland... 

Figure 9.1 The distribution of 5-HT neurons in the brain. The cell bodies are clustered in nuclei (B1-B7) in the pons/upper medullary regions of the brainstem. The rostral cluster ( superior group ) project mainly to forebrain areas while the caudal ( inferior ) group projects mainly to the medulla and spinal cord. Collectively, these neurons innervate most regions of the central nervous system...

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