Residual effect of growth regulators in etiolation and regeneration of in vitro pineapple plants

This work aimed to evaluate the influence of naphthaleneacetic acid (NAA) and gibberellic acid (GA3) plant regulators in in vitro etiolation and subsequent regeneration of the PE x SC-60 pineapple hybrid. Nodal segments of in vitro plants with approximately 5-7 cm height were incubated in basic MS culture medium supplemented with 0.0; 0.5 and 1.0 mg L-1 of naphthaleneacetic acid (NAA) in combination with gibberellic acid (GA3) in concentrations of 0.0; 0.5 and 1.0 mg L-1, and maintained at 27 ºC under dark condition. Evaluations were carried out at 90 and 180 days after incubation period. The best results for length of etiolated stems were obtained with 1.0 mg L-1 of NAA. In the experiment followed by the regeneration, stems with 3 cm from the etiolation treatment, were cultivated in proliferation medium and the number of regenerated plants per treatment was evaluated at 60 days of cultivation. The treatment that promoted the best etiolation of plants also promoted the worst regeneration rates, demonstrating the residual effect of the auxin used in the previous step in the regeneration of plants of the pineapple hybrid evaluated.

Ultrastructural calli analysis of Inga vera Willd. subsp. Affinis (DC.) T.D. Penn

Subcellular changes are relevant to understand plant organogenesis and embryogenesis in the early stages of cell development. The cytology during cell development in tissue culture is however still poorly characterized. This study aimed to characterize the ultrastructural differences related to callogenesis of anthers, ovaries, leaf and nodal segments of Inga vera Willd. subsp. Affinis (DC.) T.D. Penn. Flower buds, nodal segments and leaves were disinfected and inoculated in test tubes containing MS medium with 3% sucrose and 4.5µM 2.4-D, except for leaf callogenesis, where 9µM of this auxin was used, and for the callogenesis of anthers and ovaries, where the culture medium was enriched with 0.25% activated charcoal and 90µM PVP. After 45 days in culture medium, the anther, ovary, leaf and nodal segment calli were fixed in Karnovisky and prepared for visualization by scanning and transmission electron microscopy. Ultrastructural differences were observed among the callus cells of anthers, ovaries, segments and leaves. There was no evidence of somatic embryo formation in the anther, leaf and nodal segment calli, in spite of some embryogenic characteristics in the cells. The ovary calli, with indications of embryo formation, seem to be the most responsive explant source for embryogenesis.

Hydrocortisone decreases apoptosis in jejunum of horses subjected to experimental ischemia and reperfusion

In order to evaluate the effect of hydrocortisone on apoptosis in the jejunum of horses subjected to ischemia and reperfusion, ten horses were paired and grouped into two groups - treated (n=5) and non treated (n=5). Segments of the jejunum were used as controls (C), or as venous ischemia (VIsc), which were subjected to 2h of ischemia followed by 2 or 12h of reperfusion. C samples were collected at time zero (prior to ischemia) and VIsc samples were collected at 2h of ischemia and at 2 and 12h of reperfusion. TUNEL positive apoptotic cells were counted in 10 microscopical fields in deep mucosa from each horse throughout the time course. After 12h of reperfusion, the number of apoptotic cells in treated group were significantly lower than in untreated animals, indicating that hydrocortisone inhibits apoptosis. These results indicate that hydrocortisone has a beneficial effects favoring the maintenance of jejunal integrity in horses with ischemia and reperfusion injuries by preventing apoptotic cell death.

A systematic study of the brain base arteries in the turkey (Meleagris gallopavo)

Thirty heads with neck segments of turkeys (Meleagris gallopavo) were dissected for a systematic study of the arteries. The frequency of the arteries found was: Cerebral carotid artery, intercarotid anastomosis and internal ophthalmic artery (100%). Caudal branch of the cerebral carotid artery to the right (R) vestigial artery (70%) and developed (30%) and to the left (L) developed (70%) and vestigial artery (30%). Ventral tectal mesencephalic artery in (70%) to R and (30%) to L was the direct branch of the cerebral carotid artery to L (70%) and to R (30%) collateral branch of the developed caudal branch. Basilar artery to L in (70%) and to R (30%) formed from the developed caudal branch; rostral ventral cerebellar artery present (86.7%) and absent (13.3%) to R and L. Caudal ventral cerebellar artery to R single (73.3%), double (23.3%) and triple (3.3%); caudal ventral cerebellar artery to L single (73.3%) and double (26.7%). Dorsal spinal artery branch of caudal ventral cerebellar artery to R (80%) and to L (73.3%). The rostral branch of cerebral carotid artery showed as collateral branches the single caudal cerebral artery to R (100%) and to L (96.7%) while in (3.3%) it was double. The middle cerebral artery was single to R and L (100%). Cerebroethmoidal artery to R and L (100%) with its collateral branch to single rostral cerebral artery (90%) to R and (86.7%) to L and double (10%) to R and (13.3%) to L. Ethmoidal artery to R and to L (100%) single. The cerebral arterial circle was rostrally and caudally opened, so that the cerebral blood supply was exclusively made by the carotid system.

Morphological and morphometric evaluation of prepubertal gilt ovaries, uterine tubes and uterus at different oestrus cycle stages

Studies are performed in developing techniques/procedures that provide greater reproductive performance in farm animals, including pigs. In this sense, the study of gilts reproductive organs at different oestrus cycle stages for assessing the presence of abnormalities and/or other parameters that may affect the future animal fertility is important. In order to evaluate the morphological, morphometric and histomorphometric features of ovaries, uterus and uterine tubes (UTs) characteristics of prepubertal gilts at different oestrus cycle stages, reproductive tracts from 48 animals immediately after slaughter were obtained. After, the structures were dissected and removed, and the ovaries were used for classification of oestrus cycle stage of each gilt in follicular phase (FP) and luteal phase (FL). Then, morphometric evaluations of ovaries, UTs, uterine horns and uterine body were performed. Besides that, medial segments of UTs and uterus were fixed in Bouin solution, processed and included in paraffin, when histological sections of 5.0 micrometers (µm) were obtained and stained with Hematoxylin and Eosin. Histomorphometric analyzes using image capture system and specific software were performed. Afterwards, data were submitted to Student's t test for assessment the statistical differences (P<0.05) between the two different oestrus cycle stages (FP × LP) and between the placement of reproductive structures (right × left antimer). Among the gilts evaluated, 35 were in the FP and 13 in LP. There was no difference (P>0.05) between morphometric parameters of ovaries, UTs and uterus of gilts in FP and LP. Likewise, in respect to the placement of reproductive structures, both in the oestrus cycle stages, as in the general average, there was no difference (P>0.05). Regarding the histomorphometric variables, gilts classified in FP presented a higher (P<0.05) height of glandular and UT epithelium compared to animals in LP. On the other hand, the diameter of endometrial glands was higher (P<0.05) in gilts at LP compared to FP. Furthermore, gilts in LP presented a higher (P<0.05) proportion of endometrium occupied by glands, whereas animals in FP had a higher (P<0.05) proportion of connective tissue and blood vessels. In conclusion, in prepubertal gilts, the histomorphometric parameters as endometrial glands diameter, the height of glandular epithelium and of UT epithelium and the proportion of endometrium occupied by connective tissue, besides the glands and blood vessels varies through the oestrus cycle, possibly under the influence of ovarian steroids.

Triplex Doppler evaluation of the testes in dogs of different sizes

This study aimed to assess whether there are differences in Doppler velocimetry parameters between different sizes. Twenty dogs were equally divided into small and large groups used in this study. The dogs were evaluated using Triplex ultrasound. Testicular artery was located by Colour Doppler in the spermatic cord, marginal to the testes and intratesticular segments and then, spectral Doppler were used to calculate: peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI) and pulsatility index (PI). The mean testicular volume in the left side was significantly higher than the right side, in both groups. Doppler examination showed higher velocities (EDV) at spermatic cord in large dogs; marginal to the testes was observed higher velocities in small dogs; intratesticular region no differences were observed (P < 0.05) and within the groups differences between segments of the artery were also observed for each parameter. The results showed that there are differences in Doppler velocimetry parameters between different sizes.

Histological changes in banana explants, cv. Nanicão (Musa spp., Group AAA), submitted to different auxins for induction of somatic embryogenesis

The present work analyzes the behavior of banana explants, cv. Nanicão (Musa spp. Group AAA) regarding somatic embryogenesis induction treatments with several auxins. Longitudinal segments of shoot meristematic apices of micropropagated banana plantlets cultivated and rooted in vitro were introduced in culture medium containing dicamba, picloram, 2,4-D or NAA in different concentrations. Explant samples were collected at 0, 7 and 10 days and prepared for light microscopy. Histological sections were used for comparison of the histological changes occurring after induction treatment with different auxins. Embryogenic response was observed only in treatments with picloram or dicamba, with distinct embryogenic regions observed at 14 and 21 days in culture, respectively. Histological sections of embryogenic regions of the explant at 26 days in culture revealed the formation of meristematic regions, structures with multiple root meristems, and somatic embryos at early globular stages. Embryo-like structures morphologically similar to Musa balbisiana zygotic embryos were sectioned and showed a lack of apical meristems and absence of procambial differentiation. These results indicate the induction of non-functional somatic embryos and the need for more studies on developmental aspects and maturation treatments for optimization of the process.

Taxonomy and distribution of the green algal genus Halimeda (Bryopsidales, Chlorophyta) in Brazil

Halimeda is a genus of calcified coenocytic green algae with a well known ecological importance in some tropical areas. Bleached calcified segments of Halimeda may accumulate in large deposits of economic potential as is the case in the northeastern coast of Brazil. In a survey of the genus in Brazil based on recent collections and examination of abundant material deposited on Brazilian herbaria we identified seven species: Halimeda cuneata Hering, H. discoidea Decaisne, H. gracilis Harvey ex J. Agardh, H. incrassata (Ellis) Lamouroux, H. opuntia (Linnaeus) Lamouroux, H. simulans Howe and H. tuna (Ellis & Solander) Lamouroux. These species are described in detail, with emphasis on diagnostic characters. Our study has shown that the shape and size of the utricula in surface view, under scanning electron microscopy, can be utilized to discriminate some species. Fertile specimens of Halimeda cuneata and H. discoidea are reported for the first time in the region. Data on vertical and geographical distribution are presented for each species and the southern limit of the genus in the western Atlantic was extended.

Family names and the length of the Y chromosome in Brazilian blacks

The variability of the lengths of the heterochromatic and euchromatic segments of the human Y chromosome was studied by a quantitative method of densitometric measurement in 60 normal and unrelated black individuals (30 with and 30 without devotional surnames), living in Salvador, Bahia, northeastern Brazil. Thirty normal and unrelated Caucasian individuals of European origin, living in Curitiba, Paraná, south Brazil, were included as controls. The heterochromatic segment and total Y chromosome lengths were greater in caucasians than in blacks without devotional surnames, and these were greater than in blacks with devotional surnames. These findings are in agreement with previous reports of a higher percentage of black ancestry in blacks carrying devotional surnames than those carrying non-devotional ones.

Reactivity of the isolated perfused rat tail vascular bed

Isolated segments of the perfused rat tail artery display a high basal tone when compared to other isolated arteries such as the mesenteric and are suitable for the assay of vasopressor agents. However, the perfusion of this artery in the entire tail has not yet been used for functional studies. The main purpose of the present study was to identify some aspects of the vascular reactivity of the rat tail vascular bed and validate this method to measure vascular reactivity. The tail severed from the body was perfused with Krebs solution containing different Ca2+ concentrations at different flow rates. Rats were anesthetized with sodium pentobarbital (65 mg/kg) and heparinized (500 U). The tail artery was dissected near the tail insertion, cannulated and perfused with Krebs solution plus 30 µM EDTA at 36oC and 2.5 ml/min and the procedures were started after equilibration of the perfusion pressure. In the first group a dose-response curve to phenylephrine (PE) (0.5, 1, 2 and 5 µg, bolus injection) was obtained at different flow rates (1.5, 2.5 and 3.5 ml/min). The mean perfusion pressure increased with flow as well as PE vasopressor responses. In a second group the flow was changed (1.5, 2, 2.5, 3 and 3.5 ml/min) at different Ca2+ concentrations (0.62, 1.25, 2.5 and 3.75 mM) in the Krebs solution. Increasing Ca2+ concentrations did not alter the flow-pressure relationship. In the third group a similar protocol was performed but the rat tail vascular bed was perfused with Krebs solution containing PE (0.1 µg/ml). There was an enhancement of the effect of PE with increasing external Ca2+ and flow. PE vasopressor responses increased after endothelial damage with air and CHAPS, suggesting an endothelial modulation of the tone of the rat tail vascular bed. These experiments validate the perfusion of the rat tail vascular bed as a method to investigate vascular reactivity

Signaled two-way avoidance learning using electrical stimulation of the inferior colliculus as negative reinforcement: effects of visual and auditory cues as warning stimuli

The inferior colliculus is a primary relay for the processing of auditory information in the brainstem. The inferior colliculus is also part of the so-called brain aversion system as animals learn to switch off the electrical stimulation of this structure. The purpose of the present study was to determine whether associative learning occurs between aversion induced by electrical stimulation of the inferior colliculus and visual and auditory warning stimuli. Rats implanted with electrodes into the central nucleus of the inferior colliculus were placed inside an open-field and thresholds for the escape response to electrical stimulation of the inferior colliculus were determined. The rats were then placed inside a shuttle-box and submitted to a two-way avoidance paradigm. Electrical stimulation of the inferior colliculus at the escape threshold (98.12 ± 6.15 (A, peak-to-peak) was used as negative reinforcement and light or tone as the warning stimulus. Each session consisted of 50 trials and was divided into two segments of 25 trials in order to determine the learning rate of the animals during the sessions. The rats learned to avoid the inferior colliculus stimulation when light was used as the warning stimulus (13.25 ± 0.60 s and 8.63 ± 0.93 s for latencies and 12.5 ± 2.04 and 19.62 ± 1.65 for frequencies in the first and second halves of the sessions, respectively, P<0.01 in both cases). No significant changes in latencies (14.75 ± 1.63 and 12.75 ± 1.44 s) or frequencies of responses (8.75 ± 1.20 and 11.25 ± 1.13) were seen when tone was used as the warning stimulus (P>0.05 in both cases). Taken together, the present results suggest that rats learn to avoid the inferior colliculus stimulation when light is used as the warning stimulus. However, this learning process does not occur when the neutral stimulus used is an acoustic one. Electrical stimulation of the inferior colliculus may disturb the signal transmission of the stimulus to be conditioned from the inferior colliculus to higher brain structures such as amygdala

Feeding manipulation elicits different proliferative responses in the gastrointestinal tract of suckling and weanling rats

Food deprivation has been found to stimulate cell proliferation in the gastric mucosa of suckling rats, whereas the weanling period has been reported to be unresponsive in terms of proliferative activity. In the present study we analyze regional differences in the effect of milk or food deprivation on cell proliferation of the epithelia of the esophagus and of five segments of small intestine in suckling, weanling and newly weaned Wistar rats of both sexes. DNA synthesis was determined using tritiated thymidine to obtain labeling indices (LI); crypt depth and villus height were also determined. Milk deprivation decreased LI by 50% in the esophagus (from 15 to 8.35%) and small intestine (from 40 to 20%) of 14-day-old rats. In 18-day-old rats, milk and food deprivation decreased LI in the esophagus (from 13 to 5%) and in the distal segments of the small intestine (from 36-40 to 24-32%). In contrast, the LI of the epithelia of the esophagus (5%) and of all small intestine segments (around 30%) of 22-day-old rats were not modified by food deprivation. Crypt depth did not change after treatment (80 to 120 µm in 14- and 22-day-old rats, respectively). Villus height decreased in some small intestine segments of unfed 14- (from 400 to 300 µm) and 18-day-old rats (from 480 to 360 µm). The results show that, contrary to the stomach response, milk deprivation inhibited cell proliferation in the esophagus and small intestine of suckling rats, demonstrating the regional variability of each segment of the gastrointestinal tract in suckling rats. In newly weaned rats, food deprivation did not alter the proliferation of these epithelia, similarly to the stomach, indicating that weanling is a period marked by the insensitivity of gastrointestinal epithelia to dietary alterations

A pulsatile flow model for in vitro quantitative evaluation of prosthetic valve regurgitation

A pulsatile pressure-flow model was developed for in vitro quantitative color Doppler flow mapping studies of valvular regurgitation. The flow through the system was generated by a piston which was driven by stepper motors controlled by a computer. The piston was connected to acrylic chambers designed to simulate "ventricular" and "atrial" heart chambers. Inside the "ventricular" chamber, a prosthetic heart valve was placed at the inflow connection with the "atrial" chamber while another prosthetic valve was positioned at the outflow connection with flexible tubes, elastic balloons and a reservoir arranged to mimic the peripheral circulation. The flow model was filled with a 0.25% corn starch/water suspension to improve Doppler imaging. A continuous flow pump transferred the liquid from the peripheral reservoir to another one connected to the "atrial" chamber. The dimensions of the flow model were designed to permit adequate imaging by Doppler echocardiography. Acoustic windows allowed placement of transducers distal and perpendicular to the valves, so that the ultrasound beam could be positioned parallel to the valvular flow. Strain-gauge and electromagnetic transducers were used for measurements of pressure and flow in different segments of the system. The flow model was also designed to fit different sizes and types of prosthetic valves. This pulsatile flow model was able to generate pressure and flow in the physiological human range, with independent adjustment of pulse duration and rate as well as of stroke volume. This model mimics flow profiles observed in patients with regurgitant prosthetic valves.

Effect of inhibition of nitric oxide synthase on blood pressure and renal sodium handling in renal denervated rats

The role of sympathetic nerve activity in the changes in arterial blood pressure and renal function caused by the chronic administration of NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthesis, was examined in sham and bilaterally renal denervated rats. Several studies have demonstrated that sympathetic nerve activity is elevated acutely after L-NAME administration. To evaluate the role of renal nerve activity in L-NAME-induced hypertension, we compared the blood pressure response in four groups (N = 10 each) of male Wistar-Hannover rats weighing 200 to 250 g: 1) sham-operated vehicle-treated, 2) sham-operated L-NAME-treated, 3) denervated vehicle-treated, and 4) denervated L-NAME-treated rats. After renal denervation or sham surgery, one control week was followed by three weeks of oral administration of L-NAME by gavage. Arterial pressure was measured weekly in conscious rats by a tail-cuff method and renal function tests were performed in individual metabolic cages 0, 7, 14 and 21 days after the beginning of L-NAME administration. L-NAME (60 mg kg-1 day-1) progressively increased arterial pressure from 108 ± 6.0 to 149 ± 12 mmHg (P<0.05) in the sham-operated group by the third week of treatment which was accompanied by a fall in creatinine clearance from 336 ± 18 to 222 ± 59 µl min-1 100 g body weight-1 (P<0.05) and a rise in fractional urinary sodium excretion from 0.2 ± 0.04 to 1.62 ± 0.35% (P<0.05) and in sodium post-proximal fractional excretion from 0.54 ± 0.09 to 4.7 ± 0.86% (P<0.05). The development of hypertension was significantly delayed and attenuated in denervated L-NAME-treated rats. This was accompanied by a striking additional increase in fractional renal sodium and potassium excretion from 0.2 ± 0.04 to 4.5 ± 1.6% and from 0.1 ± 0.015 to 1.21 ± 0.37%, respectively, and an enhanced post-proximal sodium excretion compared to the sham-operated group. These differences occurred despite an unchanged creatinine clearance and Na+ filtered load. These results suggest that bilateral renal denervation delayed and attenuated the L-NAME-induced hypertension by promoting an additional decrease in tubule sodium reabsorption in the post-proximal segments of nephrons. Much of the hypertension caused by chronic NO synthesis inhibition is thus dependent on renal nerve activity.

Identification of clonally rearranged T-cell receptor beta chain genes in HTLV-I carriers as a potential instrument for early detection of neoplasia

We analyzed the genetic recombination pattern of the T-cell receptor beta-chain gene (TCR-beta) in order to identify clonal expansion of T-lymphocytes in 17 human T-lymphotropic virus type I (HTLV-I)-positive healthy carriers, 7 of them with abnormal features in the peripheral blood lymphocytes. Monoclonal or oligoclonal expansion of T-cells was detected in 5 of 7 HTLV-I-positive patients with abnormal lymphocytes and unconfirmed diagnosis by using PCR amplification of segments of TCR-beta gene, in a set of reactions that target 102 different variable (V) segments, covering all members of the 24 V families available in the gene bank, including the more recently identified segments of the Vbeta-5 and Vbeta-8 family and the two diversity beta segments. Southern blots, the gold standard method to detect T-lymphocyte clonality, were negative for all of these 7 patients, what highlights the low sensitivity of this method that requires a large amount of very high quality DNA. To evaluate the performance of PCR in the detection of clonality we also analyzed 18 leukemia patients, all of whom tested positive. Clonal expansion was not detected in any of the negative controls or healthy carriers without abnormal lymphocytes. In conclusion, PCR amplification of segments of rearranged TCR-beta is reliable and highly suitable for the detection of small populations of clonal T-cells in asymptomatic HTLV-I carriers who present abnormal peripheral blood lymphocytes providing an additional instrument for following up these patients with potentially higher risk of leukemia.