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By means of a suitable histochemical method free cholesterol and its esters could be detected into the epidermis layers. The results show that in the stratum spinosum keratinocytes free cholesterol appears as an amorphous or granular structure apparently protein unbound; into the stratum granulosum keratinocytes the cholesterol becomes protein-bound and its most part undergoes esterified. The extracellular compartment nearly the stratum granulosum contains a little amount of cholesterol esters loosely bound to proteins. The results suggest that free cholesterol after being synthesized into the cytoplasm of the stratum spinosum and granulosum keratinocytes, it is partially esterified and becomes protein-bound, appearing as fine granules within the cytoplasm of the granulous cells. From this site it takes to fates:1. Its most part remains into the granulous cell cytoplasm and at the same time the granulous cell develop to the horny cell it is placed on the thick cell membrane inner surface contributing to its thickness; 2. Another part after reaching the extracellular compartment it is spread over the thick membrane out surface. Inside the thick cell membrane, into the horny layer, free cholesterol is continuously esterified since the keratinizing cell migrate to the periphery; however even at the most peripheral layers the free cholesterol predominates. Either free cholesterol or its esters, contained into the keratinizing cell thick membrane, were excreted throughout the horny layer exfoliation. The keratinizing cell cytoplasm does not contain neither free cholesterol nor its esters.

A suitable histochemical method able to discriminate vitamins D and 7-dehydrocholesterol from cholesterol and its esters is proposed taking into account the alkaline permanganate-toluidine blue reaction, the alkaline permanganate-Schiff reaction and the inhibitory effect of the HgCl2-formalin fixative. This method appears specific according to the results provided by spot test. On tissue sections the alkaline permanganate-toluidine blue reaction is more sensitive and more specific than the alkaline permanganate-Schiff reaction. A previous ribonuclease treatment or the methylation effect improves the specificity of the alkaline permanganate-toluidine blue reaction. The 2.4-dinitrophenylhydrazine blockade must be used previously to the alkaline permanganate-Schiff reaction as an attempt to improve its specificity. The previous hydrolysis carried on by some suitable treatments seems very useful to detect masked vitamins D and 7-dehydrocholesterol. The oxidized products accountable for the reactivity of vitamins D and 7-dehydrocholesterol to the alkaline permanganate-toluidine blue and alkaline permanganate-Schiff reactions were discussed.

The spleen-hypophysis relationship particularly the effect of splenectomy on the body growth rate was studied on young rats from both sexes. The following experimental groups were tested: 1. sham-operated controls; 2. splenectomized rats; 3. marsupialized-spleen rats; 4. parabiosis rats; 5. parabiosis plus splenectomy from only one animal. The results were taking in basis on the regression lines of the body weight increasing on time, during 11 weeks. In addition, the hypophysis weight, the volume of its lobes and the adenohypophysis alpha, beta and cromophobe cells nuclear volume were estimated. The results show that splenectomy provides a significant increasing of body weight. The splenectomized rats show furthermore, a significant hypophysis weight increasing, a hypertrophy of its anterior lobe and morphological evidences of functional hyperactivity of its alpha-cells (estimated towards its nuclear volume increasing). The results suggest that the growth rate increasing of splenectomized young rats depends upon the adenohypophysis alpha-cells hypersecretion.

An almost specific and highly sensitive technique to detect histochemically choline-containing lipids is proposed. This technique is based on the effect of Hg++ and phosphomolybdic ion on the choline, that yields insoluble complexes able to react with diphenylcarbazide producing a deep blue or violet stain. The specificity and the sensitivity of this technique was investigated on filter paper strips loaded with choline-containing lipids, choline-free lipids, steroids, vitamins, proteins or choline hydrochloride. The results show that the choline-containing substances react positively. The choline-free substances react negatively except calciferol and vitamin A that show weakly positive results. This technique used on tissue sections appears very suitable to histochemical purposes.

The spot test carried on filter paper strips appears as a very suitable technique to investigate the reactivity of catalases, peroxidases, porphyrins (bilirubin and protoporphyrin), metalloporphyrins (haemoglobin, haemin, haematin, chlorophyll and cyanocobalamin), ferric and ferrous salts. By using this technique the specificity of the already proposed techniques admitted as appropriate to detect histochemically peroxidases and catalases was investigated. The results shown from the already proposed techniques to detect peroxidases only the alpha-naphthol reaction is somewhat specific for this enzyme, if the results were taken immediately. However, if the results were taken after 24 h, the reaction loose all specificity. The other techniques proposed to detect peroxidase are not specific, either concerning the discrimination between catalases and peroxidases activity or regarding the possibility to differenciate an enzymic from a catalytic activity provided by haemic iron containing compounds and sometimes by iron salts. Our histochemical technique already proposed as suitable to detect catalases seams to be specific, since peroxidases do not react positively. By replacing benzidine for some others hydrogen donors the peroxidases histochemical techniques remain not specific and are unable to discriminate this enzyme from catalases. Porphyrins (protoporphyrin and bilirubin), magnesium and cobalt containing metalloporhyrins (chlorophyll and cyanocobalamin) do not produce oxidation of any hydrogen donors used. Iron salts are also able to give positive results with some techniques already proposed as suitable for peroxidases and catalases detection.

The occurrence of nest of trypanosoma cruzi in the smooth muscle cells of the central veins of the adrenal glands and the inferior vena cava was studied in 21 chronic Chagas' patients, by serial sections. Nine patients presented parasites in the adrenal veins, with a total of 24 nests, and only one nest was found in the inferior vena cava. The area of muscular tissue examined was of 2944.3 mm2 for the adrenal veins and of 47808.6 mm2 for the vena cava, giving a relation of 0.815 nests/100 mm2 for the adrenal vein and of 0.002 for the vena cava. Thus the smooth muscle of the adrenal vein was 407 times more parasited than the muscular wall of the inferior vena cava. This higher parasitism of the adrenal vein by trypanosoma cruzi in chronic Chagas' disease may be determined by its greater corticosteroid concentration, which can reduce the anti-trypanosomal defenses.

By using the benzidine reaction, on filter paper strips loaded with catalases, peroxidases, porphyrins, haemic iron compounds and iron salts, it was possible to establish 2 histochemical techniques able to detect and discriminate catalases and peroxidases. Spot test analytical studies show that only peroxidases oxidize benzidine in presence of a 0.0015 M H2O2 final concentration into the incubation medium. If a 0.0035 M H2O2 final concentration is used both peroxidases and haemic iron were able to oxidize benzidine. At a 0.01 M H2O2 final concentration the oxidative property of catalases become apparent and therefore at this H2O2 concentration either peroxidases or haemic iron, as well as catalases could be detected. By increasing the H2O2 concentration into the incubation medium, when a 4M concentration was chosen to detect histochemically catalases without any peroxidases interference. Using 0.0015 M and 4 M H2O2 final concentrations into the incubation medium it is possible to discriminate histochemically catalases and peroxidases. Several inhibitors of catalases and peroxidases were used as an attempt to try a specific inhibition of only one of these enzymes. It was demonstrated that the use of inhibitors does not help the histochemical discrimination between catalases and peroxidases.

The present work consisted in evaluating the feasibility of utilizing different energy sources--corn, nixtamalized corn, sorghum and corn starch--in colostrum fermentation, by incorporating them in two different percentages, with and without the addition of acetic acid. The crude and true protein, ammonia, and dry matter content, as well as pH, total sugars, lactic acid, starches, dry matter digestibility, bacteriological count and gross energy, were studied. Results revealed that up to 10 days of fermentation, the most viable energy source was nixtamalized corn, and that the addition of acetic acid was not useful in colostrum preservation. The incorporation level of nixtamalized corn added to colostrum which rendered the best results, was that of 6.33%.

The peracetic acid-toluidine blue and the peracetic acid-Schiff reactions as well as the failure of HgCl2-formalin fixative for inhibiting these reactions appears as a very useful method for free cholesterol histochemical detection and to discriminate it from its esters and from some of its metabolic products such as 7-dehydrocholesterol and vitamins D. The cholesterol histochemical detection provided by those reactions appears specific taking into account the findings afforded by spot tests. The peracetic acid-toluidine blue reaction is very suitable for histochemical purposes on tissue sections, since it does not produces tissues damages, it is sensitive and the stained end product is almost insoluble in the solvents frequently used in histological techniques. The previous ribonuclease treatment and methylation are very useful in avoiding the basophil substances interference on the peracetic acid-toluidine blue reaction. The 2,4-dinitrophenylhydrazine carbonyl group blockade is useful to decrease the influence of carbonyl group on the peracetic acid-histological techniques. The previous ribonuclease treatment and methylation are very useful in avoiding the basophil substances interference on the peracetic acid-toluidine blue reaction. The 2,4-dinitrophenylhydrazine carbonyl group blockade is useful to decrease the influence of carbonyl group on the peracetic acid-histological techniques. The previous ribonuclease treatment and methylation are very useful in avoiding the basophil substances interference on the peracetic acid-toluidine blue reaction. The 2,4-dinitrophenylhydrazine carbonyl group blockade is useful to decrease the influence of carbonyl group on the peracetic acid-Schiff reaction. The peracetic acid-toluidine blue reaction is more sensitive and more specific than peracetic acid-Schiff reaction, since the tissues do contain Schiff reactive products unable to be 2,4-dinitrophenylhydrazine blocked which interfere on the results of the latter reaction decreasing its specificity and its sensitivity. The cholesterol histochemical detection based on the peracetic acid-toluidine blue and peracetic acid-Schiff reaction as it is suitable in discriminating free cholesterol from its esters as well as from some of its metabolic products it appears very useful for metabolic studies on tissue sections.

The red pulp's argentophil reticular cell network of the spleen is composed by 3 types of fixed cells: 1. the primitive reticular cell, slightly argentophil; 2. the small reticular cell; 3. the larger reticular cell, strongly argentophil and phagocytic. This latter shows the classical morphological characteristics attributed to the reticular cells of the spleen. The large argentophil reticular cell may become free, constituting a 4th cell type, the free macrophage. A 5th reticular cell type is the dendritic cell found into the lymphatic follicles of the white pulp. The argentophil reticular cells of the red pulp assemble together to form the reticular cells' network, that occurs inside the red pulp cords. The primitive and the small reticular cell form the fundamental network on which the large cells are apposed. The reticular cells of this network maitain relationship with the arterial terminal vessels of the red pulp, being responsible by the ellipsoid structure. In those arteriolar segments without ellipsoid and in those mammalian species devoid of ellipsoid, the white pulp reticular cells, that surround the blood vessel as a part of the lymphoid periarteriolar sheath, mix with the red pulp's reticular cells and both can hardly be discriminated. The ellipsoids are formed by large argentophil cells arranged in concentrical layers around its lumen that sometimes appear devoid of endothelial lining cells. The red pulp's argentophil reticular cells, either the small or the large ones, contributed to the structure of the splenic sinuses' wall; its thin processes surround the sinus wall outside the endothelial lining cell as fibrillar structures that cross the back side of the lining cells. Two or more argentophil reticular cells send fibrillar processes to a single sinus. The perisinusal reticular cells may send a process between adjacent endothelial lining, cells that insinuate and attain the sinus lumen; this process becomes thick and eventually, the reticular cell enter the sinus lumen as a free macrophage. The argentophil reticular cells of the red pulp make connection between the capsule or the trabeculae and the reticular cell network. The endothelial lining cells of the splenic sinuses are not argentophil.