A low dose of benzo(a)pyrene during prepuberty in male rats generated immediate oxidative stress in the testes and compromised steroidogenic enzymes/proteins

The prepubertal period is crucial for sexual development and any alterations can interfere with the reproductive system in adulthood. The aim of this study was to evaluate how Benzo(a)pyrene (BaP) can affect the testes during the prepubertal period. Juvenile male Wistar rats were divided into a control (corn oil + DMSO) and a BaP-group (0.1 μg/kg/day), exposed to BaP for 31 days (gavage), and all parameters were evaluated on postnatal day (PND) 54. Leukocyte counts were decreased. Histological analyses of the testes revealed that height and seminiferous tubules diameters (STDs) were reduced, tubular dynamics were altered, and Leydig cell atrophy was evident in the BaP-group. The testosterone concentration was decreased while FSH levels increased within the BaP-exposed group. Steroidogenic enzymes in the testes were decreased, but steroidogenic acute regulatory protein was not altered. The expression of gstp1 and ckit enzymes was decreased. Reduced glutathione (GSH) and superoxide dismutase (SOD) were increased, whereas malondialdehyde (MDA) was decreased in the testes. In conclusion, BaP or its metabolites causes low systemic toxicity; however, it adversely influences testicular function by disrupting the hormonal axis, unbalancing testicular antioxidative, and blocking the action of the steroidogenic mechanisms.

Period-Prevalence and Risk Factors for Delirium in a Tertiary Referral ICU: A prospective cohort study

BACKGROUND

Delirium is common in intensive care and leads to increases in morbidity, mortality, Intensive Care Unit (ICU) length of stay, and hospital length of stay. Certain risk factors predict the appearance of delirium.

STUDY OBJECTIVES

To determine the rates of delirium, the rate of risk factors, and their relationship to the occurrence of delirium in an adult ICU.

METHODS

Single-centre, prospective, observational study. Demographic and treatment data were collected. The Confusion Assessment Method for ICU (CAM-ICU) was performed twice daily to assess for delirium continuously during a 3-week period. Statistical analysis was used to determine the relationship between risk factors and the occurrence of delirium.

RESULTS

86 patients were screened, 44 patients were included, and 260 patient-days were analyzed. The incidence of delirium was 42.9%, the prevalence of delirium in ICU was 50%. Urinary catheters and use of opioids were the most common factors with a positive association for occurrence of delirium. Exposure to daylight and sleeping for more than 4 hours at night were the factors most commonly associated with a lack of delirium.

CONCLUSION

The rates of delirium in ICU were high and risk factors occurred frequently. Addressing modifiable risk factors, including the promotion of adequate sleep, could improve outcomes.

Serum miRNAs are differentially altered by ethanol and caffeine consumption in rats

Alcoholism is a multifactorial disease with high risk for dependence determined by genetic background, environmental factors and neuroadaptations. The excessive consumption of this substance is related to psychiatric problems, epilepsy, cardiovascular disease, cirrhosis and cancers. Caffeine is one of the most popular psychostimulants currently consumed in the world. The combination of ethanol and caffeine ingested by consuming "energy drinks" is becoming increasingly popular among young people. We analyzed the effect of simultaneous consumption of ethanol and caffeine on the serum profile of miRNAs differentially expressed in the ethanol-drinking rat model (UChB strain). Adult rats were divided into three groups (n = 5 per group): UChB group (rats fed with 1 : 10 (v/v) ethanol ad libitum); UChB + caffeine group (rats fed with 1 : 10 (v/v) ethanol ad libitum + 3 g L-1 of caffeine); control group (rats drinking water used as the control for UChB). The treatment with caffeine occurred from day 95 to 150 days old, totalizing 55 days of ethanol + caffeine ingestion. The expressions of microRNAs (miR) -9-3p, -15b-5p, -16-5p, -21-5p, -200a-3p and -222-3p were detected by Real Time-PCR (RT-PCR). The expressions of miR-9-3p, -15b-5p, -16-5p and -222-3p were upregulated in the UChB group. Conversely, simultaneous ingestion of ethanol and caffeine significantly reversed these expressions to similar levels to control animals, thus emphasizing that caffeine had a protective effect in the presence of ethanol. In addition, miR-21-5p was downregulated with ethanol consumption whereas miR-222-3p was unchanged. Ethanol and caffeine consumption was capable of altering serum miRNAs, which are potential biomarkers for the systemic effects of these addictive substances.

Human milk enriched with human milk lyophilisate for feeding very low birth weight preterm infants: A preclinical experimental study focusing on fatty acid profile

BACKGROUND

Human milk, with essential nutrients and long chain polyunsaturated fatty acids (LC-PUFAs) such as the omega 3 and 6 fatty acids is important for development of the central nervous system and the retina in very low birth weight infants (<1,500 g). However, breast milk may not be sufficient to meet these needs. The possibility of supplementing breast milk with a lyophilisate of human milk was explored in this study. The objectives of this study were to determine the total lipid content and the lipid profile of the Human Milk on Baseline (HMB) and that of the Concentrates with the Human Milk + lyophilisate (with lyophilisate of milk in the immediate period (HMCI), at 3 months (HMC3m), and at 6 months (HMC6m) of storage).

METHODS

Fifty donors from the Human Milk Bank of Children's Hospital provided consent, and donated milk samples. Macronutrient (including total lipids) quantification was performed using the MIRIS® Human Milk Analyzer, and the fatty acid profile was determined by gas chromatography (CG-FID, SHIMADZU®).

RESULTS

There was a higher lipid concentration in HMCI relative to HMB. The concentrations of the main fatty acids (% of total) were as follows: palmitic acid (C16:0) HMB, 22.30%; HMCI, 21.46%; HMC3m, 21.54%; and HMC6m, 21.95% (p<0.01); oleic acid (C18:1n-9) HMB, 30.41%; HMCI, 30.47%; HMC3m, 30.55%; and HMC6m, 29.79% (p = 0.46); linoleic acid (C18:2n-6) HMB, 19.62%; HMCI, 19.88%; HMC3m, 19.49%; and HMC6m, 19.45% (p = 0.58); arachidonic acid (C20:4n-6) HMB, 0.35%; HMCI, 0.16%; HMC3m, 0.13%; and HMC6m, 0.15% (p<0.01); α-linolenic acid (C18:3n-3) HMB,1.32%; HMCI, 1.37%; HMC3m, 1.34%; and 1.34% HMC6m (p = 0.14); docosahexaenoic acid (C22:6n-3) HMB, 0.10%; HMCI, 0.06%; HMC3m, 0.05%; and HMC6m, 0.06% (p<0.01). There were no significant changes in the lipid profile when stored. There was no evidence of peroxidation during storage.

CONCLUSIONS

Freeze-dried human milk fortified with a human milk concentrate brings potential benefits to newborns, mainly by preserving the essential nutrients present only in breast milk; however, further clinical studies are required to evaluate the safety and efficacy of the concentrate as a standard nutritional food option for very low birth weight infants.

Gavage Feed Volume Determines the Gastric Emptying Rate in Preterm Infants

OBJECTIVE

Feeding intolerance, manifesting as increased gastric residual, is a common finding in preterm neonates. Little is known about the regulation of gastric emptying early in life and the extent to which this plays a role in the preterm infants' feeding tolerance. The goal of this study was to evaluate clinically stable 28- to 32-week gestation neonates during the first 4 weeks of life and noninvasively determine their gastric emptying rate.

STUDY DESIGN

Ultrasound measurements of gastric milk content volume were obtained from 25 neonates immediately after, 30 and/or 60 minutes following routine gavage feeds. The content emptying rate was calculated from the gastric volume data.

RESULTS

Gastric emptying rate was not postnatal age-dependent, was significantly higher at 30 minutes, whenever compared with 60-minute postfeed and directly proportional to the feed volume. At any postnatal age, the gastric emptying rate was at least 6-fold greater, when comparing the lowest and highest average stomach content volumes.

CONCLUSIONS

The gastric emptying rate of preterm infants is content volume-dependent and unrelated to the postnatal age. Given the present findings, further investigation on the gastric residual of preterm infants receiving larger than currently administered feed volumes at the initiation of enteral nutrition, is warranted.

Association between type of feeding at discharge from the hospital and nutritional status of very low birth weight preterm infants

The ideal feeding for premature babies has been the source of extensive debate. The aim of this study was to assess the association between type of feeding at discharge and the nutritional status of very low birth weight infants. This was a retrospective cohort of preterm babies with birth weight ≤1500 g, born between January 2006 and December 2013. The infants were divided into 3 groups according to type of feeding at discharge: exclusive breast milk (group 1), mixed feeding (group 2) and exclusive artificial formula (group 3). Frequencies of each group were calculated, as well as mean Z-score differences in weight, length and head circumference. Six hundred and forty-nine newborns were included. The mean weight of groups 1, 2, and 3 was 1338.7, 1104.0, and 1254.7 g, respectively, and their mean gestational age was 31.9, 30, and 31.2 weeks, respectively. The Z-score differences (means±SD) for groups 1, 2, and 3 were: −0.84±0.68, −1.02±0.75, and −0.86±0.71 for weight, −0.21±1.23, −0.52±1.64 and −0.08±1.34 for head circumference, and −1.10±1.18, −1.54±1.37, and −0.97±1.21 for length. A significant difference was observed between groups 2 and 3 in the adjusted Z-score model for length, with no significant differences in anthropometric measurements for the other comparative analyses. Because of its many advantages, breastfeeding should be stimulated within neonatal units since nutritional status was not influenced by the different types of feeding.

Maternal separation on the ethanol-preferring adult rat liver structure

Background and rationale for the study. We designed to test whether there is interaction of maternal separation (MS) on the ethanol-preferring rats liver structure. The UCh rat pups were separated daily from their mothers during the stress hyporesponsive period (SHRP), between four and 14 days-old, always at the same time for four hours in a cage containing eight subdivisions, one for each pup. Subsequently, rats that presented the highest (UChB) and the lowest (UChA) ethanol (EtOH) consumption were selected to the study. Both UChB and UChA rats received 10% (v/v) EtOH and distilled water ad libitum until the end of the experiment (120 days-old). The liver was collected to histological routine for morphometric and stereological analyses, and immunohistochemistry.

RESULTS

There was an interaction of MS and EtOH on the liver: increased liver mass, peritubular vessels, stellate cell numbers, steatosis and cell death, decreased necrosis, sinusoidal capillary diameters and cell proliferation. While there was a decrease in FSH, testosterone and 5α-di-hidrotestosterone, and increasing corticosterone and cholesterol.

CONCLUSIONS

There is interaction of MS and EtOH on the liver structure, dependent on the amount of EtOH intake. Furthermore, the interaction of stress and drugs can increase or decrease their effects on the liver or indirectly via hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes.

Idiopathic interstitial pneumonia in the ICU: an observational cohort

In the absence of a clearly identifiable cause, the prognosis of patients with interstitial lung disease is grim. This study describes our institutional experience in management of patients who are admitted to an ICU with respiratory insufficiency secondary to idiopathic interstitial pneumonia (IIP). This study was performed to obtain Australian data on patients admitted to an ICU with respiratory insufficiency secondary to IIP. This is a retrospective cohort study of patients with IIP who were admitted to the ICU between December 2007 and December 2013 at one of two university-affiliated academic hospitals in Newcastle, New South Wales. Thirty-six patients (69% male) were admitted to the ICU in respiratory insufficiency from IIP. The median age of the cohort was 71 (66 to 77) years. The median APACHE III score was 68 (56 to 97). Sixty-nine percent (25/36) of patients died in hospital. The median ICU and hospital lengths of stay were 6 (2 to 13.5) and 12 (4.8 to 18.3) days respectively. No significant difference was observed between admission characteristics and mortality. Patients admitted to ICU with respiratory failure secondary to IIP are aggressively investigated and treated, but still have a high mortality rate. Accurate predictors of mortality would be useful in offering aggressive treatment to patients who would benefit from it.

Effects of therapeutic approach on the neonatal evolution of very low birth weight infants with patent ductus arteriosus

OBJECTIVE

To analyze the effects of treatment approach on the outcomes of newborns (birth weight [BW] < 1,000 g) with patent ductus arteriosus (PDA), from the Brazilian Neonatal Research Network (BNRN) on: death, bronchopulmonary dysplasia (BPD), severe intraventricular hemorrhage (IVH III/IV), retinopathy of prematurity requiring surgical (ROPsur), necrotizing enterocolitis requiring surgery (NECsur), and death/BPD.

METHODS

This was a multicentric, cohort study, retrospective data collection, including newborns (BW < 1000 g) with gestational age (GA) < 33 weeks and echocardiographic diagnosis of PDA, from 16 neonatal units of the BNRN from January 1, 2010 to Dec 31, 2011. Newborns who died or were transferred until the third day of life, and those with presence of congenital malformation or infection were excluded. Groups: G1 - conservative approach (without treatment), G2 - pharmacologic (indomethacin or ibuprofen), G3 - surgical ligation (independent of previous treatment). Factors analyzed: antenatal corticosteroid, cesarean section, BW, GA, 5 min. Apgar score < 4, male gender, Score for Neonatal Acute Physiology Perinatal Extension (SNAPPE II), respiratory distress syndrome (RDS), late sepsis (LS), mechanical ventilation (MV), surfactant (< 2 h of life), and time of MV.

OUTCOMES

death, O2 dependence at 36 weeks (BPD36wks), IVH III/IV, ROPsur, NECsur, and death/BPD36wks.

STATISTICS

Student's t-test, chi-squared test, or Fisher's exact test; Odds ratio (95% CI); logistic binary regression and backward stepwise multiple regression. Software: MedCalc (Medical Calculator) software, version 12.1.4.0. p-values < 0.05 were considered statistically significant.

RESULTS

1,097 newborns were selected and 494 newborns were included: G1 - 187 (37.8%), G2 - 205 (41.5%), and G3 - 102 (20.6%). The highest mortality was observed in G1 (51.3%) and the lowest in G3 (14.7%). The highest frequencies of BPD36wks (70.6%) and ROPsur were observed in G3 (23.5%). The lowest occurrence of death/BPD36wks occurred in G2 (58.0%). Pharmacological (OR 0.29; 95% CI: 0.14-0.62) and conservative (OR 0.34; 95% CI: 0.14-0.79) treatments were protective for the outcome death/BPD36wks.

CONCLUSION

The conservative approach of PDA was associated to high mortality, the surgical approach to the occurrence of BPD36wks and ROPsur, and the pharmacological treatment was protective for the outcome death/BPD36wks.

Response of oxygen saturation in preterm infants receiving rib cage stabilization with an elastic band in two body positions: a randomized clinical trial

BACKGROUND

Preterm newborns have higher thoracic compliance, providing less stability to the different forces of distortion imposed on the rib cage, leading to instability of the chest. Adequate body position may reduce this instability and facilitate respiratory work.

OBJECTIVE

To assess the oxygen saturation response of preterm newborns receiving rib cage stabilization with an elastic band in two body positions.

METHOD

A clinical, prospective, randomized crossover study was conducted, including sixteen newborns with a gestational age of 31 to 35 weeks (mean 32.8 weeks) at a tertiary care facility, who did not receive supplemental oxygen. The infants were placed in a sequence of prone and supine positions with and without chest stabilization with an elastic band. Respiratory rate, heart rate, and oxygen saturation were measured at 10-minute intervals, corresponding to 7 samplings of 60 minutes. Data collection was interrupted when oxygen saturation was less than 90%.

RESULTS

The mean gestational age of the infants was 32.8±1.5 weeks and the mean birth weight was 1,789±255 g. Better values for the variables studied were observed in the supine position with an elastic chest band compared to the supine position without the band. The positions using an elastic band resulted in lower mean respiratory rate and heart rate and higher oxygen saturation.

CONCLUSION

The use of an elastic chest band improves respiratory indicators such as oxygen saturation.

Examining the side effects of sucrose for pain relief in preterm infants: a case-control study

Sucrose solution is recommended as relevant pain relief management in neonates during acute painful procedures; however, only a few studies have analyzed the potentially adverse effects of sucrose administration to preterm neonates. The goal of this study was to examine the potential side effects of sucrose for pain relief in preterm infants, assessing feeding and weight gain during hospitalization and their feeding patterns postdischarge. The study sample consisted of 43 preterm neonates divided into two groups: a sucrose group (SG, n=18) and a control group (CG, n=25) in which no sucrose was administered. The SG received 0.5 mL/kg 25% oral sucrose for 2 min prior to all acute painful procedures during three consecutive days. A prospective review of medical charts was performed for all samples. The study was done prior to implementation of the institutional sucrose guidelines as a routine service, and followed all ethical requirements. There were no statistically significant differences between groups in terms of weight gain, length of stay with orogastric tubes, and parenteral feeding. Postdischarge, infant nutritional intake included feeding human milk to 67% of the SG and 74% of the CG. There were no statistically significant differences between groups regarding human milk feeding patterns postdischarge. Neonate feeding patterns and weight gain were unaffected following the short-term use of sucrose for pain relief.

Effect of body position on preterm newborns receiving continuous positive airway pressure

AIM

To evaluate the effect of body position on the cardiorespiratory indicators of preterm newborns receiving nasal continuous positive airway pressure (CPAP).

METHODS

Analytical, observational, prospective, cross-sectional, randomised crossover study was carried out on sixteen newborns that received nasal CPAP. The infants had a mean gestational age of 29.7 ± 2 weeks and birthweight of 1353 ± 280 g. Cardiorespiratory indicators (respiratory rate, heart rate and oxygen saturation) were evaluated in each infant in the supine, prone and right and left lateral decubitus positions at intervals of 10 min over a period of 60 min.

RESULTS

The cardiorespiratory indicators were similar and within the normal range in the four decubitus positions. There was no difference in respiratory or heart rate between body positions. Although they showed desirable values, oxygen saturation was significantly lower in left lateral decubitus (96.6 ± 1.7%) when compared to the supine (97.1 ± 1.3%) and prone positions (97.4 ± 1.1%) (p = 0.00) and was also significantly lower in right lateral decubitus (96.9 ± 1.4%) when compared to the prone position (p = 0.00).

CONCLUSION

We found no preferential decubitus position for preterm newborns receiving nasal CPAP, the supine position may be a choice, but the left and right lateral positions were less advantageous in terms of oxygen saturation.

Application of continuous positive airway pressure in the delivery room: a multicenter randomized clinical trial

This study evaluated whether the use of continuous positive airway pressure (CPAP) in the delivery room alters the need for mechanical ventilation and surfactant during the first 5 days of life and modifies the incidence of respiratory morbidity and mortality during the hospital stay. The study was a multicenter randomized clinical trial conducted in five public university hospitals in Brazil, from June 2008 to December 2009. Participants were 197 infants with birth weight of 1000-1500 g and without major birth defects. They were treated according to the guidelines of the American Academy of Pediatrics (APP). Infants not intubated or extubated less than 15 min after birth were randomized for two treatments, routine or CPAP, and were followed until hospital discharge. The routine (n=99) and CPAP (n=98) infants studied presented no statistically significant differences regarding birth characteristics, complications during the prenatal period, the need for mechanical ventilation during the first 5 days of life (19.2 vs 23.4%, P=0.50), use of surfactant (18.2 vs 17.3% P=0.92), or respiratory morbidity and mortality until discharge. The CPAP group required a greater number of doses of surfactant (1.5 vs 1.0, P=0.02). When CPAP was applied to the routine group, it was installed within a median time of 30 min. We found that CPAP applied less than 15 min after birth was not able to reduce the need for ventilator support and was associated with a higher number of doses of surfactant when compared to CPAP applied as clinically indicated within a median time of 30 min.

Nasal CPAP in the delivery room for newborns with extremely low birth weight in a hospital in a developing country

The objective of this study was to determine the feasibility of the use of continuous positive airway pressure installed prophylactically in the delivery room (DR-CPAP), for infants with a birth weight between 500 and 1000 g in settings with limited resources. During 23 months, infants with a birth weight between 500 and 1000 g consecutively received DR-CPAP. A total of 33 infants with low birth weight were enrolled, 16 (48.5%) were females. Only 14 (42.4%) received antenatal corticosteroids and only 2 of those 14 (14.3%) infants weighing 500-750 g were not intubated in the delivery room, and apnea was given as the reason for intubation of these patients. Of the 19 infants in the 751-1000 g weight range, 9 (47.4%) were intubated in the delivery room, 6 due to apnea and 3 due to respiratory discomfort. For DR-CPAP to be successful, it is probably necessary for preterm babies to be more prepared at birth to withstand the respiratory effort without the need for intubation. Antenatal corticosteroids and better prenatal monitoring are fundamental for success of DR-CPAP.

Proactive management of extreme prematurity: disagreement between obstetricians and neonatologists

OBJECTIVE

To verify, in extremely preterm infants, if disagreement between obstetricians and neonatologists regarding proactive management is associated with early death.

STUDY DESIGN

Prospective cohort of 484 infants with 23(0/7) to 26(6/7) weeks, without malformations, born from January 2006 to December 2009 in eight Brazilian hospitals. Pro-active management was defined as indication of ≥1 dose of antenatal steroid or cesarean section (obstetrician) and resuscitation at birth according to the international guidelines (neonatologist). Main outcome was neonatal death in the first 24  h of life.

RESULT

Obstetricians and neonatologists disagreed in 115 (24%) patients: only neonatologists were proactive in 107 of them. Disagreement between professionals increased 2.39 times the chance of death in the first day (95% confidence interval 1.40 to 4.09), adjusted for center and maternal/neonatal clinical conditions.

CONCLUSION

In infants with 23 to 26 weeks of gestation, disagreement between obstetricians and neonatologists, translated as lack of antenatal steroids and/or vaginal delivery, despite resuscitation procedures, increases the odds of death in the first day.

Pediatric pain: prevalence, assessment, and management in a teaching hospital

The goal of this study was to examine the prevalence, assessment and management of pediatric pain in a public teaching hospital. The study sample consisted of 121 inpatients (70 infants, 36 children, and 15 adolescents), their families, 40 physicians, and 43 nurses. All participants were interviewed except infants and children who could not communicate due to their clinical status. The interview included open-ended questions concerning the inpatients' pain symptoms during the 24 h preceding data collection, as well as pain assessment and pharmacological/non-pharmacological management of pain. The data were obtained from 100% of the eligible inpatients. Thirty-four children/adolescents (28%) answered the questionnaire and for the other 72% (unable to communicate), the family/health professional caregivers reported pain. Among these 34 persons, 20 children/adolescents reported pain, 68% of whom reported that they received pharmacological intervention for pain relief. Eighty-two family caregivers were available on the day of data collection. Of these, 40 family caregivers (49%) had observed their child's pain response. In addition, 74% reported that the inpatients received pharmacological management. Physicians reported that only 38% of the inpatients exhibited pain signs, which were predominantly acute pain detected during clinical procedures. They reported that 66% of patients received pharmacological intervention. The nurses reported pain signs in 50% of the inpatients, which were detected during clinical procedures. The nurses reported that pain was managed in 78% of inpatients by using pharmacological and/or non-pharmacological interventions. The findings provide evidence of the high prevalence of pain in pediatric inpatients and the under-recognition of pain by health professionals.

Chronic ethanol consumption alters all-trans-retinoic acid concentration and expression of their receptors on the prostate: a possible link between alcoholism and prostate damage

BACKGROUND

Ethanol (EtOH) alters the all-trans-retinoic acid (ATRA) levels in some tissues. Retinol and ATRA are essential for cell proliferation, differentiation, and maintenance of prostate homeostasis. It has been suggested that disturbances in retinol/ATRA concentration as well as in the expression of retinoic acid receptors (RARs) contribute to benign prostate hyperplasia and prostate cancer. This study aimed to evaluate whether EtOH consumption is able to alter retinol and ATRA levels in the plasma and prostate tissue as well as the expression of RARs, cell proliferation, and apoptosis index.

METHODS

All animals were divided into 4 groups (n = 10/group). UChA: rats fed 10% (v/v) EtOH ad libitum; UChACo: EtOH-naïve rats without access to EtOH; UChB: rats fed 10% (v/v) EtOH ad libitum; UChBCo: EtOH-naïve rats without access to EtOH. Animals were euthanized by decapitation after 60 days of EtOH consumption for high-performance liquid chromatography and light microscopy analysis.

RESULTS

EtOH reduced plasma retinol concentration in both UChA and UChB groups, while the retinol concentration was not significantly different in prostate tissue. Conversely, plasma and prostate ATRA levels increased in UChB group compared with controls, beyond the up-regulation of RARβ and -γ in dorsal prostate lobe. Additionally, no alteration was found in cell proliferation and apoptosis index involving dorsal and lateral prostate lobe.

CONCLUSIONS

We conclude that EtOH alters the plasma retinol concentrations proportionally to the amount of EtOH consumed. Moreover, high EtOH consumption increases the concentration of ATRA in plasma/prostate tissue and especially induces the RARβ and RARγ in the dorsal prostate lobe. EtOH consumption and increased ATRA levels were not associated with cell proliferation and apoptosis in the prostate.

Variations in maternal care alter corticosterone and 17beta-estradiol levels, estrous cycle and folliculogenesis and stimulate the expression of estrogen receptors alpha and beta in the ovaries of UCh rats

BACKGROUND

Variations in maternal care are associated with neonatal stress, hormonal disturbances and reproductive injuries during adulthood. However, the effects of these variations on sex hormones and steroid receptors during ovary development remain undetermined. This study aimed to investigate whether variations in maternal care are able to influence the hormonal profile, follicular dynamics and expression of AR, ER-alpha and ER-beta in the ovaries of UCh rat offspring.

METHODS

Twenty-four adult UCh rats, aged 120 days, were randomly divided into two groups (UChA and UChB) and mated. Maternal care was assessed from birth (day 0) to the 10th postnatal day (PND). In adulthood, twenty adult female rats (UChA and UChB offspring; n = 10/group), aged 120 days, were euthanized by decapitation during the morning estrus.

RESULTS

UChA females (providing high maternal care) more frequently displayed the behaviors of carrying pups, as well as licking/grooming and arched back nursing cares. Also, mothers providing high care had elevated corticosterone levels. Additionally, offspring receiving low maternal care showed the highest estrous cycle duration, increased corticosterone and 17beta-estradiol levels, overexpression of receptors ER-alpha and ER-beta, increased numbers of primordial, antral and mature follicles and accentuated granulosa cell proliferation.

CONCLUSIONS

Our study suggests that low maternal care alters corticosterone and 17beta-estradiol levels, disrupting the estrous cycle and folliculogenesis and differentially regulating the expression of ER-alpha and ER-beta in the ovaries of adult rats.

Melatonin reduces LH, 17 beta-estradiol and induces differential regulation of sex steroid receptors in reproductive tissues during rat ovulation

BACKGROUND

Melatonin is associated with direct or indirect actions upon female reproductive function. However, its effects on sex hormones and steroid receptors during ovulation are not clearly defined. This study aimed to verify whether exposure to long-term melatonin is able to cause reproductive hormonal disturbances as well as their role on sex steroid receptors in the rat ovary, oviduct and uterus during ovulation.

METHODS

Twenty-four adult Wistar rats, 60 days old (+/-250 g) were randomly divided into two groups. Control group (Co): received 0.9% NaCl 0.3 mL+95% ethanol 0.04 mL as vehicle; Melatonin-treated group (MEL): received vehicle+melatonin [100 μg/100 g BW/day] both intraperitoneally during 60 days. All animals were euthanized by decapitation during the morning estrus at 4 a.m.

RESULTS

Melatonin significantly reduced the plasma levels of LH and 17 beta-estradiol, while urinary 6-sulfatoximelatonin (STM) was increased at the morning estrus. In addition, melatonin promoted differential regulation of the estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR) and melatonin receptor (MTR) along the reproductive tissues. In ovary, melatonin induced a down-regulation of ER-alpha and PRB levels. Conversely, it was observed that PRA and MT1R were up-regulated. In oviduct, AR and ER-alpha levels were down-regulated, in contrast to high expression of both PRA and PRB. Finally, the ER-beta and PRB levels were down-regulated in uterus tissue and only MT1R was up-regulated.

CONCLUSIONS

We suggest that melatonin partially suppress the hypothalamus-pituitary-ovarian axis, in addition, it induces differential regulation of sex steroid receptors in the ovary, oviduct and uterus during ovulation.

Long-term exogenous melatonin treatment modulates overall feed efficiency and protects ovarian tissue against injuries caused by ethanol-induced oxidative stress in adult UChB rats

BACKGROUND

Chronic ethanol intake leads to reproductive damage including reactive oxygen species formation, which accelerates the oxidative process. Melatonin is known to regulate the reproductive cycle, food/liquid intake, and it may also act as a potent antioxidant indoleamine. The aim of this study was to verify the effects of alcoholism and melatonin treatment on overall feed efficiency and to analyze its protective role against the oxidative stress in the ovarian tissue of UChB rats (submitted to 10% [v/v] voluntary ethanol consumption).

METHODS

Forty adult female rats (n = 10/group) were finally selected for this study: UChB Co: drinking water only; and UChB EtOH: drinking ethanol at 2 to 6 ml/100 g/d + water, both receiving 0.9% NaCl + 95% ethanol 0.04 ml as vehicle. Concomitantly, UChB Co + M and UChB EtOH + M groups were infused with vehicle + melatonin (100 μg/100 g body weight/d) intraperitoneally over 60 days. All animals were euthanized by decapitation during the morning estrus (4 am).

RESULTS

Body weight gain was reduced with ethanol plus melatonin after 40 days of treatment. In both melatonin-treated groups, it was observed a reduction in food-derived calories and liquid intake toward the end of treatment. The amount of consumed ethanol dropped during the treatment. Estrous cycle was longer in rats that received both ethanol and melatonin, with prolonged diestrus. Following to oxidative status, lipid hydroperoxide levels were higher in the ovaries of ethanol-preferring rats and decreased after melatonin treatment. Additionally, antioxidant activities of superoxide dismutase, glutathione peroxidase activity, and glutathione reductase activity were increased in melatonin-treated groups.

CONCLUSIONS

We suggest that melatonin is able to affect feed efficiency and, conversely, it protects the ovaries against the oxidative stress arising from ethanol consumption.

IGFR-I expression and structural analysis of the hard palatine mucosa in an ethanol-drinking rat strain (UChA and UChB)

The study analyzed the effects of chronic alcohol ingestion on the ultrastructure of the lining epithelium of the hard palatine mucosa of rats UChA and UChB (lines with voluntary alcohol consumption) in order to contribute to the understanding of the consequences of alcohol abuse for the morphology of the digestive system. Thirty female adult animals aged 120 days were divided into three experimental groups. (1) Ten UChA rats (genetically low ethanol consumer) with voluntary intake of 10% v/v (5.45 g/kg/day) ethanol solution and water. (2) Ten UChB (genetically high ethanol consumer) rats with voluntary intake of 10% v/v (7.16 g/kg/day) ethanol solution and water. (3) Ten Wistar rats with voluntary ad libitum water intake (control group). Both groups received Nuvital pellets ad libitum. The IGFR-I expression was intense in both experimental groups. The epithelial cells of the alcoholic rats UChA and UChB showed many alterations such as the presence of lipid droplets, altered nuclei, nuclei in corneum layer and disrupted mitochondria. It was concluded that ethanol intake induces ultrastructural lesions in the hard palatine mucosa.

Long-term melatonin treatment reduces ovarian mass and enhances tissue antioxidant defenses during ovulation in the rat

Melatonin regulates the reproductive cycle, energy metabolism and may also act as a potential antioxidant indoleamine. The present study was undertaken to investigate whether long-term melatonin treatment can induce reproductive alterations and if it can protect ovarian tissue against lipid peroxidation during ovulation. Twenty-four adult female Wistar rats, 60 days old (± 250-260 g), were randomly divided into two equal groups. The control group received 0.3 mL 0.9% NaCl + 0.04 mL 95% ethanol as vehicle, and the melatonin-treated group received vehicle + melatonin (100 µg·100 g body weight(-1)·day(-1)) both intraperitoneally daily for 60 days. All animals were killed by decapitation during the morning estrus at 4:00 am. Body weight gain and body mass index were reduced by melatonin after 10 days of treatment (P < 0.05). Also, a marked loss of appetite was observed with a fall in food intake, energy intake (melatonin 51.41 ± 1.28 vs control 57.35 ± 1.34 kcal/day) and glucose levels (melatonin 80.3 ± 4.49 vs control 103.5 ± 5.47 mg/dL) towards the end of treatment. Melatonin itself and changes in energy balance promoted reductions in ovarian mass (20.2%) and estrous cycle remained extensive (26.7%), arresting at diestrus. Regarding the oxidative profile, lipid hydroperoxide levels decreased after melatonin treatment (6.9%) and total antioxidant substances were enhanced within the ovaries (23.9%). Additionally, melatonin increased superoxide dismutase (21.3%), catalase (23.6%) and glutathione-reductase (14.8%) activities and the reducing power (10.2% GSH/GSSG ratio). We suggest that melatonin alters ovarian mass and estrous cyclicity and protects the ovaries by increasing superoxide dismutase, catalase and glutathione-reductase activities.

Brazilian multicenter study on prevalence of preterm birth and associated factors

Background

The occurrence of preterm birth remains a complex public health condition. It is considered the main cause of neonatal morbidity and mortality, resulting in a high likelihood of sequelae in surviving children. With variable incidence in several countries, it has grown markedly in the last decades. In Brazil, however, there are still difficulties to estimate its real occurrence. Therefore, it is essential to establish the prevalence and causes of this condition in order to propose prevention actions. This study intend to collect information from hospitals nationwide on the prevalence of preterm births, their associated socioeconomic and environmental factors, diagnostic and treatment methods resulting from causes such as spontaneous preterm labor, prelabor rupture of membranes, and therapeutic preterm birth, as well as neonatal results.

Methods/Design

This proposal is a multicenter cross-sectional study plus a nested case-control study, to be implemented in 27 reference obstetric centers in several regions of Brazil (North: 1; Northeast: 10; Central-west: 1; Southeast: 13; South: 2). For the cross sectional component, the participating centers should perform, during a period of six months, a prospective surveillance of all patients hospitalized to give birth, in order to identify preterm birth cases and their main causes. In the first three months of the study, an analysis of the factors associated with preterm birth will also be carried out, comparing women who have preterm birth with those who deliver at term. For the prevalence study, 37,000 births will be evaluated (at term and preterm), corresponding to approximately half the deliveries of all participating centers in 12 months. For the case-control study component, the estimated sample size is 1,055 women in each group (cases and controls). The total number of preterm births estimated to be followed in both components of the study is around 3,600. Data will be collected through a questionnaire all patients will answer after delivery. The data will then be encoded in an electronic form and sent online by internet to a central database. The data analysis will be carried out by subgroups according to gestational age at preterm birth, its probable causes, therapeutic management, and neonatal outcomes. Then, the respective rates, ratios and relative risks will be estimated for the possible predictors.

Discussion

These findings will provide information on preterm births in Brazil and their main social and biological risk factors, supporting health policies and the implementation of clinical trials on preterm birth prevention and treatment strategies, a condition with many physical and emotional consequences to children and their families.

Ovarian structure and hormonal status of the UChA and UChB adult rats in response to ethanol

OBJECTIVES

In females, chronic alcoholism has a current and dangerous incidence to fertility. This work had the goal of elucidating the alterations on the ovary of UChA and UChB adult rats (ethanol 10% (v/v) voluntary drinkers).

STUDY DESIGN

After the treatment period, 42 female rats divided into three experimental groups (UChA, UChB and Wistar) suffered decapitation and their ovaries were removed and processed to further analysis on light and electron microscopy. The ovary was entirely sliced and stained by hematoxylin-eosin, toluidine blue, periodic acid Schiff (PAS) and Masson's tricromic. Thereby, the enzymatic reaction to acid and alkaline phosphatase, estral cyclicity, reproductive hormonal status and frequency in oestrous-related ovarian structures were assigned.

RESULTS

The UChB rats showed an increase in body mass gain index and the ovaries relative weight was significantly lower comparing to the other groups. UCh rats presented the longest estral cycle durations and also persistent oestrous phasis, with uninterrupted cycles. Advanced follicular atresia was common in UCh animals, and degenerating intracellular fragments could be observed through acid phosphatase and electron microscopy techniques.

CONCLUSIONS

There were some estral cyclicity irregularities caused by chronic ethanol intake in the UCh groups which were consequently reflected as morphologic injury in the ovary structure.

Plasma amino acids in pregnancy, placental intervillous space and preterm newborn infants

Plasma amino acid levels have never been studied in the placental intervillous space of preterm gestations. Our objective was to determine the possible relationship between plasma amino acids of maternal venous blood (M), of the placental intervillous space (PIVS) and of the umbilical vein (UV) of preterm newborn infants. Plasma amino acid levels were analyzed by ion-exchange chromatography in M from 14 parturients and in the PIVS and UV of their preterm newborn infants. Mean gestational age was 34 +/- 2 weeks, weight = 1827 +/- 510 g, and all newborns were considered adequate for gestational age. The mean Apgar score was 8 and 9 at the first and fifth minutes. Plasma amino acid values were significantly lower in M than in PIVS (166%), except for aminobutyric acid. On average, plasma amino acid levels were significantly higher in UV than in M (107%) and were closer to PIVS than to M values, except for cystine and aminobutyric acid (P < 0.05). Comparison of the mean plasma amino acid concentrations in the UV of preterm to those of term newborn infants previously studied by our group showed no significant difference, except for proline (P < 0.05), preterm > term. These data suggest that the mechanisms of active amino acid transport are centralized in the syncytiotrophoblast, with their passage to the fetus being an active bidirectional process with asymmetric efflux. PIVS could be a reserve amino acid space for the protection of the fetal compartment from inadequate maternal amino acid variations.

Morphologic changes in the urethral epithelium in an ethanol-drinking rat strain (UChA and UChB)

The extreme use of ethanol causes metabolic and pathologic changes in testes and urogenital system in different animal species. The enzyme alcohol dehydrogenase (ADH) catalyses the conversion of ethanol into carcinogenic metabolite acetaldehyde which is partly excreted into the urine. However, papers relating the chronic ethanol consumption to the urethral morphology are unknown. This work evaluates the toxic effect of the chronic ethanol ingestion on the urethral epithelium of UChA and UChB rats. Conventional techniques of histology, histochemistry, immunohistochemistry and ultrastructural analysis were used. The analysis showed the presence of lipid drops and intercellular spaces in the epithelial cells in the urethra of UChA and UChB rats compared to control rats. Urethral neuroendocrine cell were observed and characterized for presenting vesicles containing electron-dense granules associated with nervous fibers. We conclude that the chronic consumption of ethanol induces the presence lipid drops in the epithelial cells of the urethra of UChA and UChB rats. The NE cells of the urethra of UChA and UChB rats did not show alterations under chronic effect of the ethanol.

Evaluation of the ethanol intake on the Calomys callosus seminal vesicle structure

The effects of chronic alcohol ingestion on the structure of the glandular epithelium of the seminal vesicle of the rodent Calomys callosus were analyzed in 24 adult animals aged 3 months divided into three experimental groups. The control group received a solid diet and tap water, the alcoholic group received the same solid diet and ethanol P.A. diluted 20% in water (v/v) for 4 months. The abstinent group received the same liquid diet of the alcoholic one for the same period and after that the alcoholic diet was changed by water for a period of 3 months. After treatment, all animals were anesthetized, weighed and sacrificed. At the end of treatment, mean body weight did not differ between animal groups. The glandular epithelial cells of the alcoholic and abstinent groups showed atrophy and ultrastructural alterations such as the presence of altered nuclei, intense dilatation of the cisterns of the granular endoplasmic reticulum, intense digestive vacuoles and lipid droplets. Ethanol ingestion provokes marked lesions on the epithelium of the seminal vesicle probably interfering on the glandular secretion.

Morphological alterations on the prostate of Calomys callosus submitted to chronic ethanol ingestion

The objective of the present study was to assess the possible toxic effects of chronic alcohol ingestion on the ultrastructure of the glandular epithelium of the prostate of the rodent Calomys callosus, in order to contribute to the understanding of the consequences of alcohol abuse for the morphology of the male reproductive apparatus. Sixteen adult animals aged three months were divided into two experimental groups. The control group received a solid diet and tap water, and the alcoholic group received the same solid diet and ethanol P.A. diluted 20% in water (v/v). After 120 days of treatment, all animals were anesthetized, weighed and sacrificed. At the end of treatment, mean body weight did not differ between control and alcoholic animals. The prostate epithelial cells of the alcoholic group showed intense atrophy and ultrastructural alterations such as the presence of lipid droplets, altered nuclei, ruptured mitochondrial cristae, and intense dilatation of the cisterns of the granular endoplasmic reticulum. It was concluded that 20% ethanol provokes marked lesions on the epithelium of the prostate probably interfering on the glandular secretion.

Repercussions of castration and vasectomy on the ductal system of the rat ventral prostate

Diseases, such as cancer and benign prostatic hyperplasia, are related to disruption of the mechanism regulating the balance between cell proliferation and apoptosis in prostatic cells. Since castration and vasectomy might alter that balance, this study evaluates the cell proliferation, apoptosis and height of the secretory epithelium of the ventral-prostate ductal system post-castration and vasectomy. Immunohistochemical (PCNA and Ki67), cytochemical (Fuelgen reaction) and morphometric investigation have been carried out. Cell proliferation indices decreased significantly in both regions of the ventral-prostate ductal system after castration compared to the sham-operated group. The apoptotic index increased significantly after 48 h, declining 7 days post-castration. The cell proliferation indices did not differ after 48 h significantly; however, they increased 7 days post-vasectomy in both regions. The apoptotic index did not differ significantly in either time post-vasectomy. Castration caused an imbalance in favor of apoptosis, whereas vasectomy caused an imbalance in favor of cell proliferation.

[The efficacy of sucrose for the relief of pain in neonates: a systematic review of the literature]

OBJECTIVE

To present a review of empirical studies published from 1993 to 2004 on the efficacy of sucrose solution for relieving pain in neonates.

SOURCES OF DATA

Information was obtained from the MEDLINE/PsycINFO/ISI WEB of SCIENCE/LILACS and SciELO databases by searching for "sucrose", "pain", "newborn" and "neonate".

SUMMARY OF DATA

Sucrose solution has demonstrated efficacy in pain relief during puncture procedures on samples of preterm and fullterm neonates. The recommendation is to administer oral sucrose, to the front of the tongue, 2 minutes before the painful procedure. Other non-pharmacological interventions, such as human breastmilk via nasogastric tube, non-nutritional suckling and being held at the breast, also demonstrated synergic analgesic effects when administered in association with sucrose. The majority of studies demonstrated a positive pain relief effect with a single 2 ml dose at 25%. Conclusions could not be drawn on the best repeat administration scheme; in the few studies that did provide an indication, the dose was 0.1 ml at 24%. The analgesic pain relief effect promoted by the sucrose was observed through altered behavioral responses, facial activity and crying. Heart rate underwent larger reductions as a result of sucrose administration during painful procedures than any of the other physiological responses.

CONCLUSIONS

The efficacy of a single dose of sucrose for the relief of acute pain neonates is well documented in the literature. However, there are not yet definite conclusions on the scheme of use for repeated doses of sucrose.

Spermatogenic cycle length and spermatogenic efficiency in the gerbil (Meriones unguiculatus)

The gerbil (Meriones unguiculatus) is a rodent native of the arid regions of Mongolia and China. Because the gerbil can be easily bred in laboratory conditions, this species has been largely used as an experimental model in biomedical research. However, there is still little information concerning the testis structure and function in the gerbil. In this regard, we performed a detailed morpho-functional analysis of the gerbil testis and estimated the spermatogenic cycle length utilizing 3H-thymidine as a marker for germ cell progression during their evolution through the spermatogenic process. The stage frequencies of the XII stages characterized according to the acrosome formation and development were (I-XII) 13.8, 10.1, 8.1, 7.8, 4.0, 11.2, 7.5, 7.1, 5.9, 7.6, 8.1, and 8.9. The mean duration of each seminiferous epithelium cycle was determined to be 10.6 +/- 1.0 days and the total duration of spermatogenesis, based on 4.5 cycles, was approximately 47.5 days. The volume density of tubular and interstitial compartments was approximately 92% and 8%, respectively. Based on the volume occupied by seminiferous tubules in the testis and the tubular diameter, about 9 and 18 m of seminiferous tubules were found per testis and per gram of testis, respectively. Twelve primary spermatocytes were formed from each type A1 spermatogonia. The meiotic index was 2.8, indicating that 30% of cell loss occurs during meiosis. The number of Leydig and Sertoli cells per gram of the testis was 28 million and each Sertoli cell was able to support approximately 13 spermatids. The daily sperm production per gram of testis (spermatogenic efficiency) was 33 million. Taken together, these data indicate that, mainly due to the high seminiferous tubule volume density and Sertoli cell support capacity for germ cells, the gerbil presents high spermatogenic efficiency compared with other mammalian species already investigated. The data obtained in the present study might provide the basis for future research involving the reproductive biology in this species.

Ultrastructural changes on the hard palatine mucosa of Calomys callosus after 120 days of experimental chronic alcoholism

The present study analyzed the toxic effects of chronic alcohol ingestion on the ultrastructure of the lining epithelium of the hard palatine mucosa of the rodent Calomys callosus, in order to contribute to the understanding of the consequences of alcohol abuse for the morphology of the digestive system. Twenty-six adult animals aged three months were divided into two experimental groups. The control group received a solid diet and tap water, and the alcoholic group received the same solid diet and ethanol P.A. diluted 20% in water (v/v). After 120 days of treatment, all animals were anaesthetised, weighed and sacrificed. At the end of treatment, mean body weight did not differ between control and alcoholic animals. The epithelial cells of the alcoholic group showed many alterations such as the presence of lipid droplets, nuclei in corneum layer, nuclei with increase peripheral chromatin and greater electron density, altered mitochondria, and intense dilatation of the intercellular spaces. It was concluded that 20% ethanol provokes marked ultrastructural lesions in the hard palatine mucosa.

Amino acid composition of parturient plasma, the intervillous space of the placenta and the umbilical vein of term newborn infants

The objective of the present study was to determine the levels of amino acids in maternal plasma, placental intervillous space and fetal umbilical vein in order to identify the similarities and differences in amino acid levels in these compartments of 15 term newborns from normal pregnancies and deliveries. All amino acids, except tryptophan, were present in at least 186% higher concentrations in the intervillous space than in maternal venous blood, with the difference being statistically significant. This result contradicted the initial hypothesis of the study that the plasma amino acid levels in the placental intervillous space should be similar to those of maternal plasma. When the maternal venous compartment was compared with the umbilical vein, we observed values 103% higher on the fetal side which is compatible with currently accepted mechanisms of active amino acid transport. Amino acid levels of the placental intervillous space were similar to the values of the umbilical vein except for proline, glycine and aspartic acid, whose levels were significantly higher than fetal umbilical vein levels (average 107% higher). The elevated levels of the intervillous space are compatible with syncytiotrophoblast activity, which maintain high concentrations of free amino acids inside syncytiotrophoblast cells, permitting asymmetric efflux or active transport from the trophoblast cells to the blood in the intervillous space. The plasma amino acid levels in the umbilical vein of term newborns probably may be used as a standard of local normality for clinical studies of amino acid profiles.

Correlation between standing height, sitting height, and arm span as an index of pulmonary function in 6-10-year-old children

The present study evaluates the relationships of pulmonary volumes and flows and the anthropometric variables of standing height, sitting height, and arm span in 100 6-10-year-old children. To be included in the study, all children were required to be healthy and above the 3rd percentile of the curve of Tanner et al. (Arch Dis Child 1966;41:454-471; Arch Dis Child 1966;41:613-635) for height and weight. Standing height, sitting height, and arm span were measured according to standard protocol. The pulmonary function measurements were: tidal volume, minute respiratory volume, respiratory rate, expiratory reserve volume, inspiratory capacity, vital capacity, residual volume (RV), functional residual capacity, total lung capacity (TLC), forced vital capacity (FVC), forced expiratory volume in 1 sec of FVC (FEV(1)), forced expiratory flow measured between 25-75% of FVC, and FEV(1)/FVC and RV/TLC ratios. Simple linear regression best expressed the correlation between pulmonary function and the anthropometric variables. Significant correlations between anthropometric and pulmonary function measurements were observed, with FVC and FEV(1) showing the highest and RV the lowest r(2) values. There was a significant positive correlation between standing height and arm span according to linear regression and Bland-Altman comparison (Bland and Altman, Lancet 1968;8:307-310). Our results suggest that when an accurate determination of standing height cannot be obtained, arm span could be used interchangeably, using the same regression equation. However, for patients with limb deformities, regression equations of pulmonary function measurements in relation to sitting height may be a better choice for estimating pulmonary function.

Morphology of the vas deferens in an ethanol-drinking strain of rats (UChA and UChB)

Chronic alcoholism alters reproduction and therefore may be responsible for alterations of vas deferens, which are the subject of this analysis in UCh ethanol-drinking rats. The proximal and distal segments of the vas deferens of 20 animals were submitted to macroscopic, light microscopy, electron microscopy and morphometric analysis. The UCh rats showed atrophy of the epithelium of the vas deferens and alterations of the hypothalamus-pituitary axis. Ethanol induces changes in the epithelium of the vas deferens and hypothalamus-pituitary axis of UCh rats.

Ultrastructure of the urethra of the Mongolian gerbil

OBJECTIVE

The urethra is the main port of entry of sexually transmitted pathogens. However, papers on the morphology of the urethra are scarce. The Mongolian gerbil is a rodent native of the Mongolia and China and has been utilized as a laboratory animal since the 1960s. This work describes the ultrastructure of the urethra of the Mongolian gerbil to provide data for future experimental studies.

METHODS

The urethra of ten adult male gerbils was studied by transmission electron microscopy.

RESULTS

The epithelium of the pelvic urethra possesses two cell types: I and II, without the formation of cellular layers, while the penile urethra possesses cellular layers: basal, intermediate and superficial. The urethra presents neurosecretory cells belonging to the amine precursor uptake and decarboxylation system.

CONCLUSIONS

The urethral epithelium of the gerbil is a neurosecretory epithelium, part of the amine precursor uptake and decarboxylation system.

Structure of the pelvic and penile urethra--relationship with the ducts of the sex accessory glands of the Mongolian gerbil (Meriones unguiculatus)

The urethra is the main place of entry for sexually transmitted pathogens. However, there is little literature on the morphology of the urogenital system, principally the urethra and ducts of the sex accessory glands. The Mongolian gerbil is an insectivorous, herbivorous and monogamous rodent with nocturnal habits; it has been used successfully as a laboratory animal since the 1960s. Therefore, the objective of the present paper was to describe the structure and ultrastructure of the urethra and its relations to the ducts of the accessory sex glands of the Mongolian gerbil (Meriones unguiculatus), contributing to the understanding of the reproductive biology of the rodent and aiming to provide data for future experimental studies. Conventional techniques of light and scanning electron microscopy were utilized. The urethra and ducts of the accessory sex glands are similar to those of the albino rat and the mouse. However, there is variation in drainage type among accessory sex glands for the inner urethra. The ducts of the seminal vesicle, the ductus deferens, drain their contents independently into the ampullary duct that opens in the urethra. The ducts of the prostate, coagulating and bulbourethral glands drain their contents independently into the urethra.