White pulp

Felten, S.Y. and Olschowka, J., Noradrenergic sympathetic innervation of the spleen II. Tyrosine hydroxylase (TH)- positive nerve terminals from synaptic-like contacts on lymphocytes in the splenic white pulp, J. Neurosci. Res., 18, 37,1987. 

The pulps obtained from chemical pulping are brown in colour and, whilst suitable for many applications, are unsuitable for printing and writing papers which require a bright white pulp. Both chemical and mechanical pulps often require bleaching for many end uses. The colour of these pulps is mainly due to residual lignin ( 3—6%, see Table 2.2 in Chapter 2) although products derived from carbohydrate may also make a contribution. The approach to removal of colour is different in each case. 

The spleen functions as a large lymph node and is supplied with blood via a single artery which progressively divides into smaller branches. Small arterioles are surrounded by areas of lymphocytes, which are known as the white pulp of the spleen. The arterioles ultimately end in vascular sinusoids, which contain different types of cells but especially erythrocytes, hence forming the red pulp of the spleen. 

After the chemical treatment, the pulped wood is removed, washed, and screened. Unbleached, brown-colored paper is made directly for this material. Most whitened or bleached paper is made by the treatment of the pulp with chlorine, chlorine dioxide, hypochlorite, and/or alkaline extraction. In general, sulfate-pulped paper is darker and requires more bleaching and alkaline extraction to give a white pulp. 

Gupuacu is an Amazonian forest tree from Para state, Brazil. The fruits are 15-25 cm in length, 10-12 cm in diameter, and weigh between 0.8 and 2 kg. They are oblong fruits with a hard skin. The seeds contain caffeine and theobromine, alkaloids with stimulant properties. The seeds contain about 48% of a white fat similar to cocoa butter. The creamy-white pulp has an attractive and characteristic aroma and flavour. The fruits are consumed mainly as juice. 

L Splenic marginal zone lymphoma (SMZL). These tumors involve both the white and the red pulp of the spleen. In the white pulp the neoplastic cells surround or replace the germinal centers, often with effacement of the mantle cell zone, and infiltrate the marginal zone. In the red pulp the tumor cells form nodules and sheets and infiltrate the sinuses. The neoplastic lymphocytes may circulate and involve the bone marrow (H5,19). 

Hairy Cell Leukemia (HCL). This B cell malignancy primarily involves the red pulp of the spleen (not white pulp), peripheral blood, and bone marrow and is composed of medium-sized, bland-appearing lymphocytes with relatively abundant cytoplasm including hairy cytoplasmic projections. 

H6. Hanna, M., An autoradiographic study of the germinal center in spleen white pulp during early intervals of the immune response. Lab. Invest. 13, 95—104 (1964). 

The objective of bleaching is to produce a white pulp of stable color obtained at reasonable cost and a minimum deleterious effect on the physical and chemical properties of the pulp. Inasmuch as the major chromophoric substances in wood pulps are derived from the lignin substrate, it must be chemically changed to colorless configurations in a stable form, or it must be oxidized, reduced, or hydrolyzed, rendering it soluble in aqueous solutions and so removable from the pulp. The two major methods of bleaching are based on these principles (23,24). 

Properties White, pulped fibers, soluble in ether-alcohol and in nitroglycerine. 

Properties White, pulped fibers, having a nitrogen content of 13.2-13.5 per cent, only partly soluble in ether-alcohol, completely soluble in acetone. Deteriorates under heat, but is stable in moist condition. In fiber form it is a high explosive gelatinized, it is a low-order explosive. The dry fiber can be detonated with mercury fulminate. Dry guncotton can be used as initiator for the detonation of wet guncotton. Rate of detonation (13 per cent nitrogen) 6300 m/sec. (d = 1.7). 

Properties White, pulped fibers. 12.6 per cent nitrogen. Soluble in ether-alcohol (2 1) and in acetone. Less corrosive on bore of gun than guncotton. For conversion to smokeless powder it is colloided with volatile solvents with or without addition of some non-volatile solvents. 

A readily distinguished subtype, organized into the primary follicles of B-ceU zones focused around follicular dendritic cells in the white pulp of the spleen and the cortical areas of peripheral lymph nodes. 

The most important application of cellulosic materials is the production of paper. Thus wood is transformed first into pulp by mechanical or chemical modification. Hardwood trees such as eucalyptus, birch, and softwood trees like pinus and spruce are used. In the Kraft process woodchips are treated with sodium hydroxide and sodium sulfide to promote the breakdown of the linkage between lignin, some hemicelluloses, and cellulose. This produces cellulose containing residual lignin. The latter is removed by a bleaching process that can apply several oxidizing agents. White pulp is pure cellulose that is used to produce paper. 

Cortex White Pulp PALS Lymphoid follicles Germinal center Cortex Subcapsular sinus Lymphoid follicles Germinal centers High endothelial vennles Erythroid component Lymphoid component... 

Figure 2.2-10 Normal monkey spleen (A) spleen from a normal female cynomolgus monkey general appearance is similar to the rat with a relatively thin capsule, small muscular trabeculae, and abundant white pulp (B) high magnification of a normal monkey spleen note large lymphoid follicle with centrally located homogenous eosinophilic material in germinal center.

As shown in Fig. (5) , primary tumor cells in the spleen grew and invaded the while and red pulp of the spleen in mice with intrasplenically implanted LLC. The orally administered triterpenoid fractions (100 or 200 mg/kg) prevented the tumor growth and the invasion of the white pulp of the spleen. Furthermore, the orally administered triterpenoid fractions induced an accumulaiion of lymphocytes around tumor cells in the white pulp of the spleen Fig. (5) . The metastatic tumor cells in the liver also grew and invaded the hepatocytes in mice with intrasplenically implanted... 

Cook It is often said that the white pulp of the spleen lacks lymphatic drainage. Does that hold up when you use these other markers And does it persist when you induce an immune response ... 

Cyster JG, Goodnow CC. Pertussis toxin inhibits migration of B and T-lymphocytes into splenic white pulp cords. J Exp Med 1995 182(2) 581-586. 

Fig. 155. Macrophages in the marginal zone of the splenic white pulp of a male white rat (No. 30) 8 weeks after an intravenous application of 25 mg Brazilian crystallised quartz (specific surface 2 mVg). Fixed by immersion in Bouin s fluid. Paraplast. Azan modification using rubine fast rea and aniline blue (Specht 1973). Objective Leitz Pi 40/0.65. Leitz-Orthomat (x3.2). Elliptic polarised light. Agfachrome 50 L professional...

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