**8. Conclusions**

AI applications in prostate mpMRI are promising tools for more effective and efficient image interpretation, leading to improved care. In pure image interpretation, ML has shown noteworthy progress in prostate organ segmentation and volume estimation. As better-curated data becomes available for prostate lesions, ML will likely become more successful at lesion detection, volume estimation, and characterization. As ML evolves, it will indisputably change radiologists' workflow by performing many of the simple tasks in image interpretation. However, ML will not replace the role of radiologists, who are critical to solving complex clinical problems [104]. AI is poised to enhance the decisions made by radiologists. It will enable radiologists to better care for their patients rather than supersede the need for radiologists.

Similarly, ML's ability to evaluate complex datasets across different domains suggests this technique may facilitate the bridging of advanced imaging, such as mpMRI, with emerging biomarker analysis or tumor genetics. Thus, ML may form the underpinnings of radiogenomics, allowing for the integration of imaging data, blood chemistry analysis, and pathologic evaluation in forming complex models that can predict treatment response. Enabled by larger datasets and more sophisticated mathematical techniques, ML could progress to creating completely automated tools that receive a patient's prostate mpMRI images and then delineate a range of desired features, as well as giving likelihood metrics for an array of pathologies.

**Funding:** This review was partially funded by the Radiological Society of North America Medical Student Research Grant RMS1902 and the Alpha Omega Alpha Carolyn L. Kuckein Student Research Fellowship.

**Conflicts of Interest:** Author Peter D. Chang, MD, is a co-founder and shareholder of Avicenna.ai, a medical imaging startup. Author Daniel S. Chow, MD, is a shareholder of Avicenna.ai, a medical imaging startup, and a grant recipient from Cannon Inc. The other authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.


**2. Lactic acid bacteria as source of probiotics**

Etymologically the term probiotics is derived from the Greek "probios" which means "for life". In 1974 Parker [11] defined as probiotics "organisms and substances which contribute to intestinal microbial balance". Fuller in 1989 [12] defined as probiotic "a live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance". Later the Food and Agriculture Organization / World Health Organization defined probiotic bacteria as "live microorganisms which when administered in adequate amounts confer a health benefit on the host" [13]. Since probiotics can colonize the gastrointestinal tract and exert their beneficial effect long term, without requiring continuous medical intervention, they have been used for a century to treat a variety of mucosal surface infections (gut, vagina), but their use decreased after the appearance of antibiotics. However, today, probiotics are considered as an alternative solution to antibiotics due to the increasing spread of antibiotic resistance and the need for treatment cost reduction [14].

Microorganisms considered as commercial probiotics are mainly of the Lactobacillus genus with over one hundred species recognized, for example: *L. acidophilus, L. rhamnosus, L. reuteri, L. casei, L. plantarum, L. bulgaricus, L. delbrueckii, L. helveticus* [15-17]. Lactobacilli are Generally Recognized As Safe (GRAS) organisms [18,19].

Probiotic bacteria are very sensitive to many environmental stresses, such as acidity, oxygen and temperature [20,21] and they must fulfill some functional and physiological aspects such as [21,22]: a) Adherence to the intestinal epithelium and colonization of the lumen of the tract. b) Ability to stabilize the intestinal microbiota. c) Counteracting the action of harmful microorganisms. d) Production of antimicrobial substances. e) Stimulation of the immune response.

There are subcategories of the general term probiotic [23,24] which are: a) Probiotic drugs: intended to cue, treat and prevent disease. b) Probiotic foods: food ingredients and dietary supplements. c) Direct-fed microbials: probiotics for animal use. d) Designer probiotics: genetically modified. Generally, foods containing probiotic bacteria fall in the category of functional foods [25].

### **2.1. Mechanism of action of probiotics**

590 Lactic Acid Bacteria – R & D for Food, Health and Livestock Purposes

pollution by the petrochemical industry [10].

**Figure 1.** Uses and Functional Ingredients of Lactic Acid Bacteria

**2. Lactic acid bacteria as source of probiotics**

relation with human health.

considered to have "Qualified Presumption of Safety" QPS-status [9].

meats (salami), fermented vegetables (olives, sauerkraut), sourdough bread, etc [9]. The European Food Safety Authority (EFSA) has stated that several LAB strains can be

Moreover, nowadays, LAB play an important role in the industry for the synthesis of chemicals, pharmaceuticals, or other useful products (Figure 1). Also, the biotechnological production of lactic acid has recently reported that offers a solution to the environmental

This chapter will discuss recent applications of LAB as source of probiotics, starter cultures, antimicrobial agents, vitamins, enzymes and exopolysaccharides, especially those that can satisfy the increasing consumer's demands for natural products and functional foods in

Etymologically the term probiotics is derived from the Greek "probios" which means "for life". In 1974 Parker [11] defined as probiotics "organisms and substances which contribute to intestinal microbial balance". Fuller in 1989 [12] defined as probiotic "a live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance". Later the Food and Agriculture Organization / World Health Organization defined probiotic bacteria as "live microorganisms which when administered in adequate amounts confer a health benefit on the host" [13]. Since probiotics can colonize the gastrointestinal Probiotics have multiple and diverse effects on the host. The main mechanisms of action of probiotic bacteria by which they improve mucosal defenses of the gastrointestinal tract include:

c. Immunomodulation: Specific strains of probiotics might influence the innate and the acquired immune system, thus playing an important role in human diseases. Probiotic bacteria may affect the epithelial cells, the dendritic cells, the monocytes / macrophages and the various types of lymphocytes (Natural killer cells, T-cells and T-cell redistribution) directly or secondarily [33,34]. This action of probiotics could be important for the elimination of neoplastic host cells [22]. Moreover, the effects of probiotics on B-lymphocytes and antibody production resulted in an increase in IgA secretion and the enhancement of response to vaccination [34]. Recently, it was also reported that probiotics can have positive effects on the respiratory system by preventing and reducing the severity of respiratory infections, because of an increase of IgA in the bronchial mucosa [35].

Lactic Acid Bacteria as Source of Functional Ingredients 593

17, 46, 47

17, 36

17, 36

48

50-52

Lactic Acid Bacteria Effects on human health References

pH of the gut and inhibits the

Reduces blood cholesterol.

against inflammation

development of pathogens (*Salmonella*

block the generation of carcinogenic agents by reducing enzyme activities

microflora. Effective against bacterial

a. Infective diarrhea. The most studied gastrointestinal condition treated by probiotics is acute infectious diarrhea in infants. Children represent a main target of studies due to the importance of limiting the spread of diseases and decreasing the need of antibiotics (Aureli et al. 2011). Clinical trials with LAB derived probiotics (*L. rhamnosus* GG; *L. reuteri*; *L. casei*; *L. delbrueckii subsp. Bulgaricus*) support the efficacy of these probiotics in preventing diarrhea [14,49,53], due to their direct or indirect

b. Antibiotic associated diarrhea. A variety of probiotic bacteria, mainly lactobacilli have been used in the treatment and prevention of antibiotic associated diarrhea [55,56]. In a recent study *L. acidophilus* and *L. casei* seemed to be effective in reducing the risk of development of diarrhea [57]. Nevertheless, the results obtained were from pilot studies, so further investigation is needed to evaluate the

c. Clostridium difficile associated diarrhea. *C. difficile* is an opportunistic pathogen often responsible for diarrhea in vulnerable people. *L. rhamnosus* GG, has

d. Travelers diarrhea. Probiotics with Lactobacilli did not seem to be effective on such diarrhea, which is caused by bacteria, in particular enterotoxigenic E. coli [14,53]. e. Radiation induced diarrhea. Although there is little research on this subject,

probiotics seem to be promising in decreasing radiation diarrhea [53].

to decreased blood pressure

LAB derived probiotics have potential health benefits in the following situations:

*Lactobacillus acidophilus* Secretes lactic acid which reduces the

*spp*, *E. coli*).

*Lactobacillus johnsonii* Effective in inhibition of *H. pylori* and

*Lactobacillus plantarum* Produces short-chain fatty acids that

*Lactobacillus fermentum* Effective in restoration of a normal

vaginosis flora

*Lactobacillus reuteri* Reduces the duration of diarrhea 49

*Enterococcus faecium* Can reduce blood cholesterol leading

**Table 1.** Lactic acid bacteria derived probiotics and human health

interaction with the enterotoxins [54].

efficacy of probiotics on such disorders.

demonstrated positive effects on treated patients [14].

1. Diarrheal diseases:


**5. Conclusions**

The one-dimensional sorption enhanced gasification model developed in this study was verified with experimental data obtained from a 200 kW facility at IFK, University of Stuttgart. The results showed that the model is able to successfully predict the performance of the pilot plant at di fferent operation conditions. With this model, the influence of important process parameters, such as gasification temperature, steam-to-carbon ratio, solid inventory, and fuel mass flow, can be simulated. On the basis of gas composition (H2, CO, CO2, CH4, and C2H4), *LHV*, and the *M* module, the model was validated over the whole SEG temperature range. As the activity of the limestone sorbent decreases after several carbonation/calcination cycles, an additional model was integrated, which adapts the carbonation reaction kinetics depending on the circulation rate and molar flow of fresh limestone. With this possibility, three di fferent fresh limestone make-up flow rates (0.2 kg/h, 6.6 kg/h, and 15 kg/h) were simulated. A parametric study revealed a larger dependence on the limestone make-up, especially for gasification temperatures below 650 ◦C. This e ffect probably has to do with the lower circulation rate between gasifier and regenerator and the reduced transfer of fresh CaO into the gasifier with di fferent CO2 capture activities. Increasing the make-up flow rate also increases the bed activity for the same quantity of mass transferred into the gasifier. At higher temperatures, it can be assumed that this e ffect is reduced by limitations of the carbonation reaction equilibrium. Considering the reaction rates in the temperature range between 600 and 750 ◦C, a strong dependency of the limestone make-up on the carbonation reaction can be identified. Furthermore, the water–gas shift reaction is influenced due to the CO2 capture. For the other reactions considered, only a minor influence from the limestone make-up was observed.

Variation of the fuel feeding rate (22 kg/h to 40 kg/h) with a constant *S*/*C* ratio (2.2 mol/mol) revealed an increase of the bed height by a factor of 2. From the gas velocity ratio (*u*/*umf*) along the reactor height, di fferent fluidization states can be recognized. While a low fuel input led to low mixing in certain areas of the fluidized bed (*u* was only higher than *umf* by a factor of 20), high fuel input increased mixing in the whole fluidized bed. However, the entrainment of particles was also higher. Based on these evaluations, the syngas power and the gas velocities of the bubbling fluidized gasifier were described in a performance diagram which is dependent on the gasification temperature and the fuel input. Therefore, the developed model can be used as a fast and reliable engineering tool for reactor design or scale-up purposes.

**Author Contributions:** M.B. is responsible for conceptualization, simulation studies, validation, and original draft preparation. M.B. and M.S. designed the methodology of the software. Writing—review and editing, A.M.P.; supervision, G.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Ministry of the Environment Baden-Württemberg, Germany, grant number BWE13008.

**Acknowledgments:** The authors gratefully acknowledge financial supports from the project BioenergieFlex (BWE13008) funded by the Ministry of the Environment Baden-Württemberg, Germany.

**Conflicts of Interest:** The authors declare no conflict of interest.


**6.3 Increased mitochondrial oxygen consumption is associated with poor cardiac outcomes in HLHS patients**

Oxygen consumption rate (OCR) from peripheral blood mononuclear cells in 16 biventricular-CHD (BV-CHD) patients, 20 single ventricle-CHD (SV-CHD) patients, and 22 healthy controls without CHD demonstrated higher respiratory maximum and reserve in single ventricle patients with poor cardiac outcome (death or cardiac death) [87]. Apart from that, we observed a lower OCR in HLHS patients with cardiac dysfunction compared with normal controls [87]. Of the 8 SV-CHD patients with Fontan completion, we observed significantly higher OCR in 4 patients with poor cardiac outcomes (death or cardiac death) (**Figure 9a** and **b**). These changes were observed in two related respiratory parameters—respiratory maximum and respiratory reserve. In contrast, SV-CHD patients with normal cardiac function showed significantly lower OCR when compared to either SV-CHD patients with HF, BV-CHD patients, or healthy controls (**Figure 9a** and **b**). Given SV-CHD with systemic RV are known to have worse clinical outcomes than SV-CHD patients with systemic LV [88–90], we reanalyzed the data focusing on only SV patients with HLHS (systemic RV), either with or without HF. This analysis yielded similar findings with significantly higher respiratory maximum and reserve observed in the post-Fontan HLHS patients with HF. However, we observed a lower OCR in HLHS patients without HF (**Figure 9c** and **d**). In addition, there is no difference between post-Fontan SV or HLHS patients either with or without HF when compared to BV-CHD patients or control subjects in basal glycolysis by measurement ECAR. Heart tissue from *Ohia* mutant mice with HLHS showed elevated


**Chapter 8 155**

Canine Hepatic Carcinoma: Diagnoses and Treatments Via Global State-of-the-Art Approach and Traditional Chinese Veterinary Medicine *by Chih-Feng Chen, Shao-Wen Chiu, Lung-Kwang Pan and Chao-Hsun Chuang* Preface

Canine Genetics, Health and Medicine combines clinical and basic scientific research to present work being undertaken in fields including cardiovascular health, genetics, infectious and parasitic studies, and oncology. With nearly 1 billion dogs co-existing with us in the world, some living as companion animals and others free-roaming, understanding their needs and health is essential. Technology, research, and the availability and development of resources are expanding both what we know and what we understand about our canine friends. Therefore, we can push boundaries in clinical diagnosis and surgical methods, develop more pharmaceutical and surgical interventions, and better understand anatomy, physiology, pathology, and genetics. This enhanced information and innovation, alongside many other factors, enhance our diagnosis, prognosis, and treatment options and also expands our preventative medicine and general

The first section of this book is titled 'Cardiovascular Disease and Genetics.' Chapter 1 'Canine Genetics and Genomics' gives a general overview of how and why genetics is used in canine health, the advances being made, techniques being employed, and where the future lies for this field. It also explores areas in which genetics has an impact, ranging from hair color and breeding characteristics to heart disease and cancer. With increasing numbers of genetic tests becoming available commercially, both owners and veterinary professionals are often interested in not just genetic disorders but also in the vast array of information the canine genome holds such as breeding lines and phenotypic attributes and even delving into ancestry. This chapter introduces a wide range of uses for genetics, explains the background behind many of the techniques presently used, and looks at future directions of canine genomics. Chapter 2 'Diagnosis, Prognosis, Management, Treatment, Research and Advances in Canine Dilated Cardiomyopathy' shows an example of how genetic investigations have benefitted cardiovascular research. It highlights the latest advances in canine cardiomyopathy from pharmaceutical treatments to surgical procedures and healthy living advice. The chapter gives an overview of canine cardiomyopathy and discusses all the different techniques and standards presently used for diagnosis and prognosis, and the different treatment and management options available. It then continues with an in-depth look at the genetics of cardiomyopathy and its associations with other conditions. Finally, the chapter compares the genetic knowledge related to human cardiomyopathy with the information presently discovered in dogs and looks towards the future of both cardiomyopathy and advancements in technology

The second section, 'One Health,' concentrates on parasitic and yeast infections in canines Chapter 3 'The State of Knowledge on Intestinal Helminths in Free-Roaming

Dogs in Southern South America', looks at the latest research undertaken on helminths. It covers issues such as the differences between urban and rural dogs, and how zoonotic diseases pose risks beyond the species of interest, and therefore

health and care opportunities.

in this area.


**4. Conclusion**

326 Current Frontiers in Cryopreservation

**3.6 Cost of production of cryopreserved catfish sperm for the aquaculture industry**  The cost analyses for each reagent and materials used in cryopreservation per ml, g or piece is shown in Table 5. Table 6 shows the cost estimates for the 4-best cryoprotecting agents (DP,

Table 5.   DMSO-dimethylsulphoxide proved to be more efficient than other cryopreservatives in preserving sperm viability. Its potential in cryopreservation can be increased when used in combination with a 5% glucose solution, i.e. DGP and DP proved to be the best even for both trials.

Also, viability of African catfish *C. gariepinus* semen cryopreserved in liquid nitrogen can be maintained for a relatively long time provided ideal protocols are strictly followed. From economic feasibility perspective of cryopreservation of catfish semen, cryopreserved semen is economically feasible and profitable for the cryobank institute or company. The farmers are also assured of the viability of the sperm cells they are buying.

The ability of the African giant catfish (*Clarias gariepinus* Burchell, 1822) semen cryopreserved from 4-8 months with different combinations of extender and cryoprotecting agents, dimethylsulphoxide (DMSO) and glycerol with two extenders: GFR (Ginzburg fish ringer) and PBS (Phosphate buffer saline) to fertilize various egg clutch weights were investigated to evaluate the optimum clutch of egg a milliliter of cryopreserved semen can fertilize. DMSO + glucose with PBS and DMSO+ PBS only proved to be the best cryoprotectant-extender combination in maintaining viability of catfish semen. The optimum viability of the semen was also observed at 4.0-5.0 g of clutch of eggs/ml of semen with little deviation. The first trial was on dilution ratio of 1:1 but in the second trial, the semen was diluted further at a ratio of 1:20 and tested on various egg clutch weights (1, 2, 3, 4, 5 g) to evaluate the viability of cryopreservation even at further dilution. There was a significant effect of different cryoprotecting agents (p<0.05) on egg clutch weights. There was a significant effect (p<0.05) for hatchability and fertility in the first trial but only fertility in the second trial.

In another experiment we tried higher dilution ratio 1:40 and with bigger clutch of eggs (120g) of a standard female breeder (1.0 kg + 0.2 kg) simulating the practices of many commercial farmers, this time with the cryopreserved sperm. Compared with the control

Cryopreservation of the Sperm

pp. 55-60.

70.

Ibadan. Pp 335-343. ISSN 0189-9686

Vol. 9 Hors Series, pp. 35-41. Coppens International. (2009). www.coppens.eu Cryobiosystems. (2006). Fundamentals of cryobiology-

**6. References**

of the African Catfish for the Thriving Aquaculture Industry in Nigeria 329

Amupitan, P.S, Ilori, O.I, Aladele, S.E, Odofin, W. T. and Omitogun, O.G. (2010). Scaling up

Baynes, S.M., Scott, A. P. and Dawson, A. P. (1981). Rainbow trout spermatozoa: Effect of cations and pH on motility. *Journal of Fish Biology* Vol.19. pp. 259-267. Bruton, M.N. (1996). Alternative life-history strategies of catfishes. In: Legendre, M. and J.P.

http://www.Cryobiosystem.imv. com/CBS/Cryobiology/cons.cbs-asp. Hetch,T., Oellermann, L. and Verheust, L.. (1996). Perspectives and clariid catfish culture in

lagoon (Ivory Coast). *Aquaculture* Vol. 55 pp. 201-213.

secretion*. Journal of Fish Biology* Vol. 60 No. 3. pp. 545-560.

of sperm motility in teleosts. *Science* Vol. 210 pp.1145-1146.

application. *Aquaculture* Vol. 155 pp. 173-178.

Nigeria. Nov. 6-9, 2006. ISSN 0189-9686.

the viability of cryopreserved giant catfish semen in liquid nitrogen for commercial application. In: *34th Annual Conference of the Genetic Society of Nigeria.* NIHORT,

Proteau (Eds.).The Biology and culture of Catfishes. *Aquatic Living Resources,* Paris

Africa. In: Legendre, M. and Proteau, J-P. (eds.).The Biology and Culture of Catfishes. *Aquatic Living Resources. Paris*, 1996, Vol. 9, Hors Series pp. 197-206. Hogendoorn H. (1979). Controlled propagation of the African catfish, *Clarias lazera (C & V).*I. Reproductive biology and field experiments. *Aquaculture* Vol. 17 pp. 323-333. Legendre, M. (1986). Seasonal changes in sexual maturity and fecundity, and HCG-induced

breeding of the catfish *Heterobranchus longifilis* Val. (Clariidae) reared in Ebrien

quantity of ova after HCG-induced ovulation in the African catfish, *Heterobranchus longifilis* (Teleostei: Clariidae). *Aquatic Living Resources.* Paris Vol. 8 pp. 309-316. Lubzens E., Daube, N., Pekarsky, I.., Magnus, Y., Cohen, A., Yusefovich, F. and Feigin, P.

(1997). Carp (*Cyprinus carpio* L.). Spermatozoa cryobanks strategies in research and

Catfish: fine structure, motility, viability and its behaviour in seminal vesicle

of cooling and freezing on sperm motility of the endangered fish Piracanjuba *Brycon orbignyanus* (Characiformes, Characidae) *Animal Reproduction* .Vol. 3 No. l

catfish, *Clarias gariepinus* (Burchell 1822). *Ife Journal of Science* Vol. 7 No.1 pp. 63-

(2006). Potentials of short-term cryopreserved sperm of the giant African catfish*, Clarias gariepinus*( Burchell, 1822) for aquaculture in Nigeria. In: Olakojo, S.A., Ogunbodede, B.A. and Akande, S.R (Eds) Proceedings of the 31st*Annual Conference of the Genetic Society of Nigeria* pp. 141-146. NACGRAB, Moor Plantation, Ibadan,

Legendre, M. and Oteme, Z.I. (1995). Effect of varying latency period on the quality and

Mansour, N, Lahnsteiner, F. and Patzner, R. A. (2002). The spermatozoan of the African

Maria A. N., Viveiros, A. T. M., Orfao L. H., Oliveira, A. V. and Morales, G. F. (2006). Effects

Morisawa, M. and Suzuki, K. (1980). Osmolality and potassium ions: their roles in initiation

Olaleye, V.F. (2005). A review of reproduction and gamete management in the African

Omitogun, O. G., Oyeleye, O.O., Betiku, C.O. Ojiokpota, C., Aladele, S.E. and Sarumi, M.B.

fresh semen that gave the highest motility at appreciably high percentage (71%) which was significantly different (P<0.05) from cryopreserved semen diluted at ratios 1:1 (50.52%) and 1:40 (49.05%). However, there was no significant difference between the two diluted cryopreserved semen (P>0.05). It was evident that the freezing process and cryopreservation decreased sperm motility after cryopreservation. It could be deduced that cryopreserved sperm still needs to be completely activated after thawing in order to fertilize the whole clutch of eggs since there is a direct relationship between motility and fertility.

In order to assist subsistence fish farmers who may not be able to obtain cryopreserved semen, the motility of sperm cells stored under refrigerated conditions in different extenders was studied. This research evaluated the effect of extenders and period of refrigerated storage on the sperm motility of *Clarias gariepinus* sperm cells with the intent to identify a suitable extender for the refrigerated storage of the sperm cells of *Clarias gariepinus.* Semen samples were collected from mature broodstock and were refrigerated with various different extenders at ratio 1:3 namely: Calcium-free Hanks' Balanced Salt Solution (Ca-F HBSS), RPMI 1640 culture medium and 0.9% NaCl. Ca-F HBSS extender was prepared at 3 different osmolalities: 200mOsmol/kg, 300mOsmol/kg and 400mOsmol/kg. Sperm cells in RPMI 1640 and 0.9% NaCl extenders were also kept at room temperature to assess the effect of refrigeration on motility of catfish sperm cells. Motility was monitored on a 24-hour basis and % motility was evaluated daily. Results showed that sperm cells of *Clarias gariepinus*  using 200mOsmol/kg as extender (p<0.05) can be stored under refrigeration for 12 days. However, of all the extenders evaluated, RPMI 1640 proved to be the most effective extender (p<0.05) retaining higher motility of the refrigerated sperm cells of *Clarias gariepinus.*

The viability of sperm preserved under ordinary refrigerated conditions is possible for a short period of time of 2-7 days depending on the amount of extender used. A culture medium like RPMI 1640 used in this study may give longer life span for sperm cells under refrigerated conditions. Extenders like RPMI 1640 or the cheaper Ca-F HBSS is an alternative that can be recommended for farmers who may have excess of sperm cells from slaughtered male fish for more female gravid eggs that can be sourced within a time period of one week.

The cost of production of a cryotube of sperm (cost of materials, reagents, liquid nitrogen, etc.) was carried out to determine the cost of a milliliter of cryopreserved sperm with a view to selling cryopreserved semen by the research laboratory to farmers who may not be able to afford to buy a male broodstock yielding an affordable cost of N100/ml compared to current cost of a male breeder which is N 1000 -1500 each (1 \$ = 165 N). This also ensures the farmer that the cryopreserved sperm cells they might alternatively buy are viable and will be able to induce the spawning of the female broodstock.


**2. Measurement of heart rate variability**

An electrocardiogram and HR data were obtained using a one-channel heart monitor (MINISCOPE II Instramed, Porto Alegre, RS, Brazil) and processed using a Lab. PC+ analogto-digital converter (Lab PC + / National Instruments, Co., Austin, TX, USA) acting as an interface between the heart rate monitor and a microcomputer. The ECG signal was recorded in real time after analog-to-digital conversion at a sampling rate of 500 Hz and the R-R intervals (ms) were calculated on a beat-to-beat basis using specific software (Silva et al., 1994). To evaluate the effect of body position on the HR response and its variability, R-R intervals were recorded over a 15-min period under resting conditions with the subjects in the supine and sitting positions, respectively.

HR and R-R intervals (RRI) can be obtained in real time, beat-by-beat, using the ECG and specific software (Silva et al., 1994). First, a visual inspection of RRI (ms) distribution obtained during 900s of collection at rest in the supine condition was carried out in order to eliminate the fragments containing spikes, which resulted in an interval with higher stability of ECG RRI tracing (Task Force, 1996).