Preparation of PVP hydrogel nanoparticles using lecithin vesicles

Hydrogels micro, sub-micro and nanoparticles are of great interest for drug encapsulation and delivery or as embolotherapic agents. In this work it is described the preparation of nano and sub-microparticles of pre-formed, high molecular weight and monomer free poly(N-vinyl-2-pyrrolidone) encapsulated inside the core of lecithin vesicles. The hydrogel particles are formed with a very narrow diameter distribution, of about 800 nm, and a moderate swelling ratio, of approximately 10.

A convenient method for lecithin purification from fresh eggs

The increasing demand for fatty acid-free lecithin required modifications in existing purification methods. In this technical note we describe a purification procedure with the following steps: a) homogenization and extraction of yolks obtained from fresh eggs with acetone, b) solubilization with ethanol and solvent elimination and c) repeated solubilization/precipitation with petroleum ether/acetone. This crude extract was chromatographed on neutral alumina, which was exhaustively washed with chloroform before elution with chloroform:methanol, allowing the sequential separation of fatty acids and lecithin. Chromatographic behavior and mass spectra of the product are presented. This fast procedure yields fatty acid-free lecithin at a competitive cost.

Physicochemical properties of lecithin-based nanoemulsions obtained by spontaneous emulsification or high-pressure homogenization

Nanoemulsions composed of a medium-chain triglyceride oil core stabilized by rapeseed or sunflower lecithins were prepared by spontaneous emulsification and high-pressure homogenization. These nanoemulsions are compared with formulations stabilized by egg lecithin. Nanoemulsions obtained by high-pressure homogenization display larger droplet size (230 to 440 nm) compared with those obtained by spontaneous emulsification (190 to 310 nm). The zeta potentials of the emulsions were negative and below -25 mV. Zeta potential inversion occurred between pH 3.0 and 4.0. The results demonstrate the feasibility of preparing lipid emulsions comprising rapeseed or sunflower lecithins by spontaneous emulsification and high-pressure homogenization.

Synaptic vesicle pool size, release probability and synaptic depression are sensitive to Ca2+ buffering capacity in the developing rat calyx of Held

The calyx of Held, a specialized synaptic terminal in the medial nucleus of the trapezoid body, undergoes a series of changes during postnatal development that prepares this synapse for reliable high frequency firing. These changes reduce short-term synaptic depression during tetanic stimulation and thereby prevent action potential failures during a stimulus train. We measured presynaptic membrane capacitance changes in calyces from young postnatal day 5-7 (p5-7) or older (p10-12) rat pups to examine the effect of calcium buffer capacity on vesicle pool size and the efficiency of exocytosis. Vesicle pool size was sensitive to the choice and concentration of exogenous Ca2+ buffer, and this sensitivity was much stronger in younger animals. Pool size and exocytosis efficiency in p5-7 calyces were depressed by 0.2 mM EGTA to a greater extent than with 0.05 mM BAPTA, even though BAPTA is a 100-fold faster Ca2+ buffer. However, this was not the case for p10-12 calyces. With 5 mM EGTA, exocytosis efficiency was reduced to a much larger extent in young calyces compared to older calyces. Depression of exocytosis using pairs of 10-ms depolarizations was reduced by 0.2 mM EGTA compared to 0.05 mM BAPTA to a similar extent in both age groups. These results indicate a developmentally regulated heterogeneity in the sensitivity of different vesicle pools to Ca2+ buffer capacity. We propose that, during development, a population of vesicles that are tightly coupled to Ca2+ channels expands at the expense of vesicles more distant from Ca2+ channels.

Ultrastructural study on the morphological changes to male worms of Schistosoma mansoni after in vitro exposure to allicin

INTRODUCTION: Garlic has a wide range of actions, including antibacterial, antiviral, antifungal, antiprotozoal and anthelmintic actions. This antiparasitic activity has been attributed to allicin, which is the main constituent of garlic. The present study aimed to investigate the in vitro activity of allicin on the tegument of adult Schistosoma mansoni worms using scanning electron microscopy. METHODS: Swiss Webster mice were infected with S. mansoni cercariae (100 per mouse) and sacrificed 50 days later to acquire the adult worms. These worms were collected by perfusion and placed in RPMI medium 1,640 at 37°C before transferring to RPMI media containing 0 (control), 5, 10, 15 and 20mg/mL of allicin, where they were incubated for 2h. The worms were fixed in 2.5% glutaraldehyde solution, washed twice, post-fixed in osmium tetroxide, washed twice and then dehydrated with ascending grades of ethanol. The samples were air-dried, mounted on stubs, gold coated in an ion sputtering unit and viewed using a scanning electron microscope. RESULTS: A concentration of 5mg/mL caused wrinkling in the tegument; a concentration of 10mg/mL resulted in changes to tubercles and loss or modification of spines. With 15 and 20mg/mL increasing damage to the tegument could be seen, such as vesicle formation and the presence of ulcers. CONCLUSIONS: These findings demonstrate the effect of allicin on adult S. mansoni worms and indicate that most of the changes occur at concentrations greater than that normally indicated for treatment.

Histologia del sistema reproductor masculino de Helobdella hyalina (Hirudinea, Glossiphoniidae) en Argentina

A detailed preliminary histological analysis of Helobdella hyalina Ringuelet, 1942 male system from Los Talas, Buenos Aires, Argentina is described. Six pairs of testisacs, located between the crop caeca, form the male reproductive system. Each testisac is clothed by the mesotelium. Inside it, the germinal cells are connected to the citophore and develop functional unit called poliplast. The spermatozoa are released into testisacs after the reabsortion of the citophore. Five stages of spermatogenesis are described taking into account the successive maturation stages of germinal cells and the changes in the citophore size. Lining cells and gland cells were found in the seminal vesicle. Five different types of gland cells are placed inside the ejaculatory ducts, as well as two kinds of cells are found in its distal portion: type 1, which produces eosinophilic granular secretion, type 2, with amorphous and slightly eosinophilic. Three distinct gland cells are located in the proximal portion of the duct: type 3, which produces a strongly eosinophilic granular secretion; type 4, with a negative eosinophilic amorphous secretion and type 5, with a basophilic granular secretion. Type 5 gland cells are described for the ducts of this species only.

Lipoides do plasma normal

1. In a series of 21 normal cases we found for fatty acids per 100 cc. of plasma an average of 332 mgm., being 314 mgm. for the male sex and 350 mgm. for the female sex. 2.- For lecithin, in four normal cases we found per 100 cc. of plasma 182 mgm. estimated by the contents is phosphorus which ranged from 6.12 to 9.0 mgrs. 3.- Cholesterol in 20 normal cases showed 172 mgm. per 100 cc. of plasma. The averages were 151 mgm. for men and 194 mgm. for women. 4.- The readings of the fractions were 2.01 for the ratio fatty acids divided by lecithins 0.90 for lecithin divided by cholesterol and 1.93 for fatty acids divided by cholesterol. 5.- On comparing the results obtained by us with those reported in foreign literature an absolute conformity is noted chiefly with the values supplied by Bloor and Horiuchi for the ratios among the various lipoid fractions. The average for Cholesterol is comparable with that obtained by Myers but is slightly under that of Bloor's. The lecithin contents found by us did not reach such high values as those supplied by foreign authors.

Observation on the morphology of Australorbis glabratus

The present morphological study of A. glabratus was based on the observation of shell, radula, renal region and genitalia of 50 specimens having a shell diameter of 18 mm. In this summary we record the data pertaining to the chracteristics that can be used in systematics. The numerals refere to the mean and their standard deviation; no special reference being made, they correspond to length measurements. Shell: 18 mm in diameter, 5.59 ± 0.24 mm in greatest width, 5 to 6 whorls. Right side umbilicated, left one weakly depressed. Last whorl about thrice as tall as the penultimate one at the aperture, the measurements being taken on the right side. Aperture perpendicular or a little oblique. Body, extended: 47.06 ± 3.31 mm. Renal tube: Narrow and elongated, 23.84 ± 1.90 mm, showing a pigmented ridge along its ventral surface. Ovotestis: 12.78 ± 1.50 mm. Mainly trifurcate diverticula attaching in fan-like manner to the collecting canal (this arrangement is seen to best advantage in the cephalic middle of the ovotestis). The collecting canal greatly swells at the cephalic end, narrowing suddenly as it leaves the ovotestis. Ovisperm duct: 13.70 ± 1.68 mm, including the non-unwound seminal vesicle. The latter, situated about 1 mm from the beginning af the ovisperm duct, was 1.14 ± 0.29 mm in greatest diameter, and is beset by numerous short diverticula. Sperm duct: 14.16 ± 1.27 mm, pursuing a sinous course along the oviduct. Prostate: Prostate duct 5.53 ± 0.74 mm, collecting a row of long diverticula, the latter 21.6 ± 3.5 in number. Last diverticulum generally simple or bifurcate, penultimate generally arborescent, bifurcate or simple, antepenultimate nearly always arborescent, the remaining ones arborescent. The arborescent diverticula frequently give off secondary branches. Vas deferens: 17.50 ± 2.05 mm. The ratio vas deferens/vergic sac was 4.7 ± 0.6. Verge: 3.70 ± 0.54 mm long, 0.12 ± 0.03 mm wide. Free end tapering to a point where the sperm canal opens. No penial stylet. Vergic sac: 3.77 ± 0.50 mm long, 0.19 ± 0.01 mm wide. The length ratio vergic sac/preputium was 1 ± 0.02. Preputium: Deeply pigmented, 3.79 ± 0.40 mm long, 0.89 ± 0.12 mm wide in the middle. Muscular diaphragm between it and the vergic sac. Two muscular pilasters along its lateral walls. Oviduct: 10.24 ± 1.29 mm, suddenly swollen at the cephalic end so that it forms a folded pouch capping the beginning of the uterus. Uterus: 10.58 ± 1.18 mm. Vagina: 2.06 ± 0.15 mm long, 0.32 ± 0.05 mm wide, showing a swelling at its caudal portion, just above the opening of the spermathecal duct. Spermatheca: 1.57 ± 0.41 mm long, 0.92 ± 0.23 mm wide. Spermathecal duct 1.15 ± 0.23 mm. Radula: 125 to 163 rows of teeth (mean 141.4 ± 9.8). Radula formula 27-1-27 to 34-1-34 (mean 30.9 ± 1.7).

Observations on the morphology of Australorbis nigricans

A morphological study was done on A. nigricans, based on the observation of shell, radula, renal region and genitalia of 50 specimens measuring 18 mm in diameter. The data obtained are to be compared with those recorded in our previous paper (PARAENSE & DESLANDES, 1955) on A. glabratus. The characteristics common to both species will not be mentioned here. The numerals refere to the means and their standard deviations: no special reference being done, they correspond to length measurementes. Shell - 18 mm in diameter, 6.37 ± 0.29 mm in greatest width, 6 whorls. Prevailing colur ferruginous sepia, a minority of olivaceous, ochreous, nigrescent and deeply black specimens being found. Right side variously depressed, umbilicated, 1.5 to 3.5 mm deep from the bottom of the umblicus to the highest level of the last whorl. Left side more depressed than the right one, broadly concave, 1.5 to 3.5 mm deep. Both sides show a varously distinct keel, that looks sharper at the left. Aperture deltoid, varying in outline and width. Body, extended - 60.26 ± 3.62 mm, less pigmented than in glabratus. Renal tube - 30.68 ± 1.69 mm, showing neither ridge nor pigmented line along its ventral surface, this negative character affording a sure means of separation from glabratus. Ovotestis - 14.48 ± 1.93 mm. Ovisperm duct - 13.04 ± 1.60 mm, including the non-unwound seminal vesicle. The latter was 0.97 ± 0,21 mm in greatest width. Carrefour - Resembling that of glabratus. Sperm duct - 21.36 ± 1.53 mm. Prostate - Prostate duct 7.14 ± 0.74 mm, collecting a row of long diverticula numbering 19.6 ± 3.1 and more separate than in glabratus. Last diverticulum generally bifurcate or arborescent, the remaining ones arborescent. Vas deferens - 28.68 ± 1.38. Ratio vas deferens/vergic sac = 6.8±0.8. Verge - 3.08 ± 0.28 mm long, 0.11 ± 0.02 mm wide. Vergic sac - 3.07 ± 0.28 mm long, about 0.20 mm wide. Ratio vergic sac/preputium = 0.84 ± 0.12. Preputium - 3.69 ± 0.47 mm long, 0.85 ± 0.10 mm wide. Albumen gland - Resembling taht of glabratus. Oviduct - 16.26 ± 1.41 mm, swollen at the cephalic end. Uterus - 13.24 ± 1.19 mm. Vagina - 1.70 ± 0.22 mm, swolen at the caudal portion. Spermatheca - 2.78 ± 0.40 mm long, 0.86 ± 0.16 mm wide. Spermathecal duct 1.11 ± 0.20 mm. Radula - 125 to 168 horizontal rows of teeth (mean 153.9 ± 8.4). Radula formula 28-1-28 to 36-1-36 (mean 31.8 ± 1.9). Mode formula 31-1-31. The morphological characteristics of the renal region and shell, and the great body length in the same condition of shell diameter, distinguish A. nigricans from the most related species A. glabratus, giving support to considering it a good species from a txonomic or phenotypic standpoint (morphospecies).

Physa Marmorata Guilding, 1828 (Pulmonata: Physidae)

A description of Physa marmorata Guilding, 1828, based on material collected at its type-locality, the Caribbean island of Saint Vincent, is presented. The shell is thin, horn-colored, surface very glossy, diaphanous. Spire acute, elevated; protoconch distinct, rounded-conical, reddish-brown; five not shouldered, broadly convex whorls with subobsolete spiral lines and thin growth lines. Aperture elongated, 1.4-2.0 times as long as the remaining shell length, narrow obovate-lunate; upper half acute-angled,lower half oval,narrowly rounded at the base, outer lip sharp, inner lip completely closing the umbilical region; a very distinct callus on the parietal wall; columellar lip with a low ridge gradually merging into the callus. ratios: shell width/shell length = 0.44 - 0.52 (mean 0.47); spire length /shell lenght = 0.33-0.41 (mean 0.39); aperture length/shell lenght = 0.59-0.67 (mean 0.62). Oral lappets laterally mucronate, foot spatulate with deeply pigmented acuminate tail. Mantle reflection with 6-10 short triangular dentations covering nearly half the right surface of the body whorl, and 4-6 covering a part of the ventral wall. Body surface with tiny dots of greenish-yellow pigment besides melanin. Renal tube tightly folded in toa zigzag course. Ovotestis diverticula acinous, laterally pressed against each other around a collecting canal. Ovispermiduct with well-developed seminal vesicle. oviduct highly convoluted, merging into a less convoluted nidamental gland which narrows to a funnel-shaped uterus and a short vagina. Spermathecal body oblong, more or less constricted in the middle and somewhat curved; spermathecal duct uniformly narrow, a little longer than be body. About 20 prostatic diverticula, simple, bifurcate or divided into a few short branches, distalmost ones assembled into a cluster. Penis long, nearly uniformly narrow; penial canal with lateral opening about the junction of its middle and lower thirds. Penial sheath with a bulbous terminal expasion the tip of which isinserted into the caudal end of the prepuce. Prepuce shouldered, much wider than the narrow portion of the penial sheath. Penial sheath/prepuce ratio about 2.08 (1.45-2.75). The main extrinsic muscles of the penial complex are a retractor, with a branch attached to the bulb, and another to the caudal end of the penial sheath; and a protractor, with a branch attached to the shoulder of the prepuce and adjoining area of the penial sheath, and another to the caudal end of the penial sheath. Egg capsule C-shaped, with 10-30 elliptical eggs (snails 10mm long) measuring about 1.10 mm (0.90-1.32) through the long axis and surrounded by an inner and an outer lamellate membranes. Jaw a simple obtusely V-shaped plate. radula will be described separately.

Physa cubensis Pfeiffer, 1839 (Pulmonata: Physidae)

A description of Physa cubensis Pfeiffer, 1839, based on 15 speciments collected in Havana, Cuba, is presented. The shell, measuring 9.0 x 4,8mm to 12.3 x 6.4mm, is ovate-oblong, thin, diaphanous, horncolored, shining. Spire elevated, broadly conical; protoconch distinct, roundish, reddish-brown. About five moderately shouldered, roundly convex whorls, penultimate whorl expanded; spiral striation subobsolete; growth line faint on the intermediate whorls, clearly visible on the body whorl, crowded here and there. Suture well impressed. Aperture elongated 2.05 - 2.67 (mean 2.27) times as long as the remaining length of the shell, narrow obovulate-lunate; upper half acute-angled, lower half oval, narrowly rounded at the base; outer lip sharp, inner lip completely closing the umbilical region; a thick callus on the parietal wall; columellar plait well marked. Ratios: shell width/shell length - 0.52-0.61 (mean 0.55); spire length/shell length = 0.27 - 0.33 (mean 0.31); aperture length/shell length = 0.67 - 0.73 (mean 0.69). Oral lappets laterally mucronate; foot spatulate with acuminate tail. Mantle relection with 6 - 8 short triangular dentations in the right lobe (columellar side) and 4 - 6 in the left lobe (near the pneumostome). Renal tube tightly folded into a zigzag course. Ovotestis, ovispermiduct, seminal vesicle, oviduct, nidamental gland, uterus and vagina as in Physa marmorata (see Paraense, 1986, Mem. Inst. Oswaldo Cruz, 81: 459-469). Spermathecal body egg-shaped or pear-shaped; spermathecal ducta uniformly narrow with expanded base, a little longer than the body. Spermiduct, prostate and vas deferens as in P. marmorata (Paraense, loc. cit.). Penis wide proximally, narrowing gradually apicad; penial canal with subterminal outlet. Penial sheath following the width of the penis and ending up by a bulbous expansion somewhat narrower than the proximal portion. Penaial sheath/prepuce ration = 1,25 - 1,83 (mean 1.49). Prepuce much wider than the bulb of the penial shealth, moderately shouldered owing to the intromission of the bulb, and with a large gland in one side of its proximal half occupating about a third of its length. Extrinsic muscles of the penial complex as in P. marmorata. Jaw a simple obtusely V-shaped plate. Radula to be described separetely.

Observations on the morphology of Pomacea lineata (Spix, 1827) (Mollusca, Ampullariidae)

This paper deals with the morpholgy of Pomacea lineata (Spix, 1827) collected at its type locality. The shell is globose, moderately heavy, horn-colored with brown spiral bands; apex subelevated; 4 - 5 rounded whorls increasing in diameter rather rapidly, separated by deep suture. Aperture large and ovoid; outer lip sharp; umbilicus narrow and deep; operculum concentric, corneous. Ratios: shell width/shell length = 0.74 - 0.83 (mean 0.78); spire length/shell length = 0.10 - 0.18 (mean 0.13); aperture length/shell length = 0.70 - 0.77 (mean 0.73). The animal is longisiphonate. Renal organ brownish with marked invagination at its right edge. Ureter elongated with its long axis transverse to the main axis of the kidney. The radula is taenioglossate (2.1.1.1.2) and has on average 35 transverse rows of teeth. The form and arrangement of the radula teeth are nearly the same as in other Ampullariidae. The testis is cream-colored and lies in the first three whorls of the spire. Spermiduct uniformly narrow, running to the base of the spire. Seminal vesicle whitish, slightly pressed dorsoventrally. Prostate cylindric and thick, similar in color to the testis. Penis whiplike, with a closed circular spermiduct. Penis pouch ovoid completely envelping the penis. Penis sheath elongated, broad prosimally, tapering distally. Its inner surface shows a longitudinal channel along its proximal half and two glands, one on the middle and the other apical. Ovary composed of branched whitish tubules situated on the surface of the digestive gland. Oviduct slender running along the columellar axis toward the base of the spire. Seminal receptalble tubiform, thick-walled and rounded proximally. Albumen gland large, pink, enclosing the receptacle and the spiral capsule gland. Vestigial male copulatory apparatus (penis and its sheath) present in all females examined.

Dinosoma clupeola sp. n. (Hemiuridae) and Pseudoacanthostomum floridensis Nahhas & Short, 1965 (Acanthostomidae), digenetic trematodes in Brazilian Marine fishes

Dinosoma clupeola sp. n. is described from Harengula clupeola, and resembles D. hawaiiense Yamaguti, 1970, from which it differs in the entire, elongate-saccular seminal vesicle, tegument weakly plicated, smaller size of body and internal organs, and slightly larger and narrower eggs. Pseudoacanthostomum floridensis Nahhas & Short, 1965 is referred to Netuma barba, which represents a new host record.

On Pomacea sordida (Swainson, 1823) (Prosobranchia, Ampullariidae)

A description of Pomacea sordida (Swainson, 1823) collected in Caxias and Nova Iguaçu, state of Rio de Janeiro, is presented. The shell is globose, heavy, whith greenish or horn-colored periostracum and dark spinal bands; apex subelevated, 4-5 moderately shoudered whorls, increasing rather rapidly and separated by deep suture. Aperture large, moderately round, yellowish or violaceous; lip thick and sometimes dark brown; umbilicus large and deep; operculum corneous and heavy, entirely closing the aperture. Ratios: shell width/shell length = 0.81-0.91 (mean 0.86); aperture length/shell length = 0.66-0.75 (mean 0.70). Testis, spermiduct and penis pouch as in Pomacea lineata (Spix, 1827). Seminal vesicle whitish and bean-shaped. Prostate cylindric and narrow, cream in coloar as the testis. Penis whiplike whith a closed circular spermiduct. Penial sheath elongated and tapered, with its distal tip turned to the right; outer basal gland situated on the left; inner median gland rounded; apical gland elongated and wrinkled. Ovary composed of branched whitish tubules lying superficially on the digestive gland; oviduct and seminal receptacle as in P. lineata; albumen gland yellowish - orange. Vestigial male copulatory apparatus (penis and its sheath) present in all females examined.