Gonadal remodeling and hormonal regulation during sex change of juvenile dusky grouper Epinephelus marginatus (Teleostei, Serranidae), an endangered protogynous hermaphrodite fish.

Sex change was induced in Epinephelus marginatus juveniles using a nonsteroidal aromatase inhibitor (AI), a synthetic androgen (17α-methyltestosterone; MT), and a combination of both (MT + AI) in a 90-day experiment. A detailed remodeling of the gonads, the plasma level of gonadal steroids, and immunostaining of pituitary follicle-stimulating hormone (FSH), luteinizing hormone (LH), and somatolactin (SL) cells were analyzed. Sex inversion reached the final spermatogenesis stages using MT, while AI triggered spermatogenesis, but reaching only the spermatid stage. Estradiol (E2) levels did not change in fish treated with AI but decreased throughout the experimental period in animals treated with MT and MT + AI. Testosterone (T) levels increased in animals treated with MT during the first 60 days (and combined with AI in the first 30 days), decreasing in all experimental groups at 90 days, while AI-treated animals had increased plasma 11-ketotestosterone (11-KT) levels after 90 days. In control fish, FSH- and SL-producing cells (ir-FSH and ir-SL) were restricted to pars intermedia (PI) of the adenohypophysis. Pituitary ir-FSH cells were decreased at the end of the experimental period in all treatments compared with the CT animals. LH-producing cells (ir-LH) were present in proximal pars distalis (PPD) and pars intermedia (PI) of adenohypophysis and did not change after the experimental period. The decreased number of ir-FSH cells at the end of the experiment in all treatments could be related to the negative feedback loop triggered by the increase in natural and/or synthetic androgens.

Testes of Astyanax altiparanae: the Sertoli cell functions in a semicystic spermatogenesis.

The Astyanax altiparanae (lambari) is a South American freshwater fish belonging to the family Characidae. Although some authors have described reproductive aspects of this species, this is the first study about the morphology of the testes throughout the annual reproductive cycle of A. altiparanae. Fish spermatogenesis differs from that in mammals as it occurs in cysts whose borders are defined by cytoplasmic processes of Sertoli cells, thus creating a favorable environment for spermatogenesis. The functions commonly attributed to fish Sertoli cells were investigated using stereological, light and electron microscopy in A. altiparanae. Results showed that when the Sertoli cells of A. altiparanae are in contact with germ cells, they plan a support function that culminates in the production of spermatozoa. After releasing spermatozoa, modified Sertoli cells form the duct epithelium, transform into secretory cells and release a secretion into the duct lumen where spermatids and sperm are located. Thus, the present study revealed important aspects of the testes of A. altiparanae, and propose a sequence of functions played by the Sertoli cells in this species.

Distribution of GnRH in the brain of the freshwater teleost Astyanax altiparanae.

GnRH is well known as a key decapeptide neurohormone involved in reproduction, stimulating the pituitary gland to release gonadotropins (LH and FSH), which, in turn, regulate steroidogenesis and gametogenesis. However, in addition to its reproductive functions, GnRH displays neuromodulatory roles with implications for sexual behavior. The pattern of distribution in the brain of GnRH may help reveal GnRH specific functions. Therefore, the main emphasis of this study is to detect the presence and distribution of GnRH in the brain of the freshwater teleost Astyanax altiparanae ("lambari"). The immunohistochemical method of peroxidase with an antibody raised against GnRH3 was used to detect the location of GnRHs in the brain and pituitary gland. Immunoreactivity to GnRH was found in the following encephalic areas: olfactory bulb, terminal nerve ganglion, preoptic area, nucleus of midbrain tegmentum, but also in torus longitudinalis, glomerular nucleus, and central and dorsal posterior nuclei of dorsal thalamus. In addition, cell bodies from neurons in the parvocellular and magnocellular periventricular nuclei and ventral tuberal nucleus along with many fibers including ones innervating the neurohypophysis were immunoreactive to a GnRH antiserum that detects all known eight GnRH peptides in teleosts. This is the first study describing the distribution of the complete GnRH system in the brain of A. altiparanae, which has great importance for aquaculture and ecology, and represents one of the major orders of South American teleosts--the Characiformes.

[Syncope and work: role of the occupational physician and global risk stratification]. / Sincope e rischio lavorativo: ruolo del medico del lavoro e stratificazione globale del rischio.

Safety risk for subjects suffering from syncope while working has not been as yet addressed by occupational medicine. The present study was aimed at evaluating a new developed methodology for job tasks risk stratification in patients with syncope. During a work-shop on syncope and occupational risk, 149 occupational physicians (OP) with about 10 years of clinical experience were asked to fulfil a Visual Analogue Scale (VAS) concerning the doctor's estimated potential damage (D) to the worker and the probability of a damage to occur (P) should syncope take place during the job task. Five job tasks characterized by different risk for safety (1, driving; 2, toxic products handling; 3, job performed closed to hot surfaces o free flames; 4, surgical activity; 5, office job) were identified. OP correctly stratified the risk associated to the different job tasks in patients with syncope. Unexpectedly, task #3 was given a risk similar to that obtained in drivers. This might be of paramount clinical and social importance when patients with syncope have to return to their job tasks.

[Syncope and occupational risk survey: the role of continuing education and multidisciplinary approach]. / Indagine conoscitiva sulla percezione del problema sincope in relazione al rischio lavorativo nella pratica clinica: ruolo della formazione e dell'approccio multidisciplinare.

Syncope is a common disorder characterized most of the times by a positive clinical outcome. However, it may turn to a life threatening event even for working colleagues and third party when occurring during an high risk job. We have recently found that, out of 670 patients admitted to the Emergency Department (ED) for syncope, about 50% were potential workers, being their age between 18 and 65 years. Also, we found that in this group of patients syncope recurrence was as high as 11% at 6 months. It is unknown how physicians address the problem of the occupational risk in patients suffering from syncope and how occupational aspects are taken into account in the clinical judgment before work readmission. One hundred eighty five doctors (149 occupational physicians, OP), participating in a work-shop on syncope, were asked to fulfill a questionnaire about their clinical experience and their attention to the occupational aspects in patients after syncope. Despite long lasting clinical experience, 41% of OP did not scrutinize syncope as a relevant symptom in their daily activity. 65% of the other specialists were used to address the occupational risk aspects in their syncope patients. A multidisciplinary approach involving continuing education on safety at work might reduce work accidents due to syncope relapse and promote a safe and suitable re-employment of patients with syncope. scrutinize syncope as a relevant symptom in their daily activity. 65% of the other specialists were used to address the occupational risk aspects in their syncope patients. A multidisciplinary approach involving continuing education on safety at work might reduce work accidents due to syncope relapse and promote a safe and suitable re-employment of patients with syncope.

Patterns of oocyte development in natural habitat and captive Salminus hilarii Valenciennes, 1850 (Teleostei: Characidae).

Fecundity and oocyte development in Salminus hilarii female brood stock were analyzed with the aim of investigating the impact of migration impediment on oogenesis. Histological analyses of the ovaries were performed in adult females caught in two different environments--the Tietê River (natural) and captivity--and the gonadossomatic index, oocyte diameter and fecundity determined. Five germ cell development stages (oogonium, perinucleolar, cortical alveoli, vitellogenic, ripe) and two other structures (postovulatory follicles and atretic oocytes) were observed in females caught in the river. Captive animals lacked the ripe oocytes and postovulatory follicles and had a relatively higher number of atretic oocytes. Females in captivity are known to produce larger oocytes, and they release fewer eggs in each spawn (absolute fecundity) when compared with animals that are able to migrate. Our results suggest that the Tietê River is undergoing alterations which are being reflected in the reproductive performance of S. hilarii, mainly due to the presence of atretic oocytes in females caught in the river. The lack of postovulatory follicles and ripe oocytes in captive animals reveals that migratory impediment negatively impacts final oocyte maturation. However, the stage of maturation reached is adequate for ovulation induction with hormone manipulation.

Immunocytochemical identification of adenohypophyseal cells in the pirarucu (Arapaima gigas), an Amazonian basal teleost.

The adenohypophysis (AH) of juvenile pirarucu (Arapaima gigas), a representative species of the Osteoglossomorpha (bonytongue fishes, one of the oldest living groups of the teleosts), was studied using histochemical and immunocytochemical methods. The AH is comprised of the pars distalis (PD), without a clear distinction between rostral pars distalis (RPD) and proximal pars distalis (PPD), and the pars intermedia (PI). The neurohypophysis (NH) is positioned on top of the PD and penetrates and branches into the PI. In the most rostral dorsal portion of the PD, adrenocorticotropic cells and fusiform gonadotropic cells were found. In the central PD, scarce prolactin-producing cells and growth-hormone-producing cells were located mainly in the dorsal part, whereas round gonadotropic cells were abundant in the ventral portion of this region. Human thyrotropin immunoreactive cells were not found in the entire AH. In the PI, melanotropic, some adrenocorticotropic, and somatolactin-producing cells were located intermingled surrounding the neurohypophyseal branches. Our results showed that the A. gigas pituitary has some basal characteristics between the ancient Actinopterygii and the more derived teleosts.

Occurrence and significance of ovarian and follicular regression in cachara Pseudoplatystoma fasciatum (Linnaeus, 1766): a histology approach

The processes of ovarian regression and follicular atresia which reproduction was not induced by hormone in confined cachara, Pseudoplatystoma fasciatum, were investigated. The macro and microscopic characteristics (oocytes diameter and histology) of the ovaries were described every 20 days, in four stages: initial regression (Rg I = first 20 days), intermediate regression (Rg II = from 21st to 40th day), final regression (Rg III = from 41st to 80th day) and the recovering stage, called resting II (R II = from 81st to 150th day). The experiment was conducted from late January (summer - longer days) to May (autumn - shorter days). In the beginning, A0 samples showed oocyte diameters ranging from 437.5 to 1,187.5mm, suggesting that oocytes were in perinucleolar, at final maturation and atretic phases. After 150 days, the diameters reached the lowest values and a ruptured zona radiata, as well as the nearly complete reabsorption of the yolk could be visualized. At the same time, a sharp decrease in the mean values of the gonadosomatic index (GSI), water temperature, photophase and rainfall was observed. The gradual involution of this long process was dynamic and complex, affecting the spawning success (fertilization, eclosion and larvae survival rates) and, consequently, the whole productive system.

Estudaram-se os processos de regressão ovariana e atresia folicular em cachara, Pseudoplatystoma fasciatum, mantida em cativeiro, na reprodução não induzida por hormônios. As características macro e microscópicas (diâmetro dos ovócitos e histologia) dos ovários foram descritas a cada 20 dias, em quatro estádios: na regressão inicial (Rg I - os primeiros 20 dias), na regressão intermediária (Rg II - do 21° ao 40° dia), na regressão final (Rg III - do 41° ao 80° dia) e na fase de recuperação ou de repouso II (R II - do 81° ao 150° dia). O experimento foi realizado do final de janeiro (verão-dias longos) a maio (outono-dias curtos). No início do experimento, as amostras apresentaram ovócitos com diâmetros que variaram de 437,5 a 1.187,5mm, sugerindo encontrarem-se nas fases perinucleolar, de maturação final e atrésicos. Aos 150 dias, os diâmetros atingiram os menores valores e pôde-se visualizar a zona radiata rompida e o vitelo reabsorvido. Concomitantemente, houve diminuição abrupta dos valores médios do índice gonadossomático, da temperatura da água, das horas de luz e de chuva. A involução gradual do longo processo foi dinâmica e complexa, afetando o êxito da desova (taxas de fertilização, de eclosão e de sobrevivência de larvas) e, conseqüentemente, o sistema produtivo.

The reproductive cycle of male catfish Pseudoplatystoma fasciatum (Teleostei, Pimelodidae) revealed by changes of the germinal epithelium. An approach addressed to aquaculture.

The aims of the present study were to analyze the gonadal structure of Pseudoplatystoma fasciatum males during their annual cycle to enhance understanding of their reproductive biology and to improve the hormonally induced reproduction and culture of this species in hatcheries. We adopted the recently proposed method that establishes reproductive classes that are based on variations of the germinal epithelium within the year. Five reproductive classes were established: maturation (early, middle, and late), regression and recrudescence. Our observations revealed that in the spawning season P. fasciatum testes display two main functions: sperm production and sperm storage. We also concluded that the analysis of the variation of germinal epithelium was satisfactory when applied to this freshwater catfish and should be adopted for other fish species.

[Syncope and work. STePS study (Short Term Prognosis of Syncope)]. / La sincope in età lavorativa. Studio multicentrico prospettico STePS.

BACKGROUND: Recurrent syncope is a common medical problem responsible for 3-5% of emergency department (ED) accesses and 1-6% of hospital admissions. If syncope occurs in a subject working in a critical safety task, the consequences of this event might be very dangerous for the worker, colleagues, others or for the environment. Therefore, syncope management is a major problem for occupational medicine, converning the general safety at work. AIMS: To evaluate the syncope events in a group of potential workers aged 18 to 65 years; to evaluate the symptoms preceding syncope and the presence of associated illnesses and recurrent events. POPULATION AND RESULTS: This study is part of the prospective study STePS (Short Term Prognosis of Syncope), and included 305 consecutive patients (aged 18-65 years, female 56%) who had syncope as a main symptom and presented at ED of four general hospitals in the Milan area, Italy, between the 23rd of January and 30th of June 2004. The 24% of subjects were hospitalized. In 21% the syncope occurs suddenly without any preceding symptom. The 67% of subjects didn't have any important illness at the time. 50% of subjects had recurrent syncope. In four subjects another syncope occurred in a 10 day follow-up. CONCLUSIONS: occupational medicine should consider syncope scrupulously. Proper diagnostic management is important to permit a correct evaluation of work safety issues.

Clinical aspects of the AIDS dementia complex in relation to histopathological and immunohistochemical variables.

To correlate cerebral histopathological and immunohistochemical changes in the neuroclinical features of the AIDS dementia complex (ADC), autopsy results of 28 ADC patients were related, in a retrospective analysis, to scores on a standardised neurological examination performed at neurologic onset. From a histopathological point of view, the cases were classified as follows: 9 cases of HIV leucoencephalopathy (HIVL; diffuse myelin damage and rare microglial nodules), 7 cases of HIV encephalitis (HIVE; several microglial nodules and no myelin damage) and 12 cases of mixed HIVL and HIVE (HIVL-E). The groups differed significantly with respect to symptoms and CD4 count at neurologic onset, survival and neurological impairment. Immunohistochemically, the interstitial component (p24-positive cells scattered singly within the white matter) was significantly more prevalent in HIVL, and the micronodular component (p24-positive cells confined within microglial nodules) in HIVE. Neurological damage was worse in cases with a high prevalence of interstitial component or a low prevalence of micronodular component. HIVE, HIVL and HIVL-E are distinct clinical forms of ADC. Neurological impairment is related to white matter damage.

Light and electron microscopy oogenesis in matrinxã, Brycon cephalus.

Oocyte development has been divided into 5 distinct stages in the reared matrinxã, Brycon cephalus, based on morphological criteria by light and transmission electron microscopy: I) chromatin-nucleolus; II) perinucleolar; III) cortical alveoli; IV) vitellogenesis; V) final maturation. In stages I and II (primary growth), oocytes reside in nests close to other oocytes (chromatin-nucleolus phase) and then within a definitive follicle (perinucleolar phase) where they greatly increase in size (the Balbiani vitelline body is the main cytoplasmic component in these latter oocytes), respectively. In stage III (cortical alveolus phase) oocytes are distinguished by the appearance of variably sized cortical alveoli and the number of these structures increases steadily towards hydration. The vitelline envelope becomes prominent. In the process of vitellogenesis (stage IV) one major accumulation of yolk proteins occurs in oocytes. In stage V (final maturation), oocyte increase slightly in size. Follicle cells go through a primordial stage and later change to a squamous and to a cubical shape. The chorion grows to a tripartite structure: an outer thin porous layer, an intermediate homogenous layer and an inner thick helicoidal layer. The ovulation of females matrinxã, required hormonal stimulation and this occurred 6 and 8 h after the second application.

Historical control data on urinary and renal tissue biomarkers in naive male Wistar rats.

Total proteins, angiotensin-converting enzyme, N-acetyl-beta-D-glucosaminidase, glutamine transaminase K and glutamine synthetase were determined in urine collected overnight (14 h: 6:00 p.m.-8:00 a.m.) from naive male Wistar rats; glutamine transaminase K and glutamine synthetase in the kidney 10,000 g supernatant and p-aminohippurate uptake in renal cortical slices also were measured. Urinary parameters were related both to urinary creatinine concentration and urinary flow rate; kidney parameters were related to protein concentration (enzymes) or slice/medium (S/M) ratio (p-aminohippurate uptake). The following reference ranges (1.0 and 99.0 percentiles) were obtained: urine: total urinary proteins (195 samples) 0.03-0.29 g mmol(-1) creatinine and 0.13-1.77 mg h(-1); angiotensin-converting enzyme (115 samples) 8.9-63.7 micromol mmol(-1) creatinine and 59.4-282.7 nmol h(-1); glutamine transaminase K (115 samples) 0-1.7 micromol mmol(-1) creatinine and 0-8.5 nmol h(-1); N-acetyl-beta-D-glucosaminidase (72 samples) 0.7-5.0 micromol mmol(-1) creatinine and 4.9-28.4 nmol h(-1) (naive male rats did not excrete glutamine synthetase); kidney: glutamine transaminase K (36 samples) 14.5-32.8 nmol mg(-1) protein; glutamine synthetase (22 samples) 13.9-48.6 nmol mg(-1) protein and p-aminohippurate (54 samples) 4.77-17.89 S/M. Urinary creatinine (r = -0.780), total urinary proteins (r = -0.521), angiotensin-converting enzyme (r = -0.650) and N-acetyl-beta-D-glucosaminidase (r = -0.796) but not glutamine transaminase K were well correlated with diuresis. In addition, the same parameters, but not glutamine transaminase K, were well correlated with creatinine (r = 0.604,0.701 and 0.747, respectively). Significant correlation also was observed between urinary indices adjusted to creatinine or urinary flow rate (total urinary proteins: r = 0.813; angiotensin-converting enzyme: r = 0.677; glutamine transaminase K: r = 0.939; N-acetyl-beta-D-glucosaminidase: r = 0.657). Finally, a low but significant correlation was found between total urinary proteins and angiotensin-converting enzyme (r = 0.293) and N-acetyl-beta-D-glucosaminidase (r = 0.471).

Tubular segment-specific biomarkers of nephrotoxicity in the rat.

Segment-specific localization of p-aminohippuric acid accumulation and glutamine synthetase activity along the proximal tubule was investigated in kidneys of rats treated with segment-specific nephrotoxicants such as potassium dichromate (pars convoluta) and hexachloro-1:3-butadiene (pars recta). Potassium dichromate and the highest dose (200 mg/kg b.w.) of hexachloro-1:3-butadiene caused a significant, dose-dependent decrease of p-aminohippuric acid uptake in the renal cortical slices 24 and 48 h after the treatment. In contrast, hexachloro-1:3-butadiene and only the highest dose (40 mg/kg b.w.) of potassium dichromate, caused a significant dose-dependent decrease of glutamine synthetase activity in the kidney beginning 24 h after treatment. Finally, potassium dichromate and the highest dose (200 mg/kg b.w.) of hexachloro-1:3-butadiene (48 h after the treatment) caused a significant dose-dependent loss of kidney protein content. The results suggest that p-aminohippuric acid accumulation is localized in the pars convoluta and confirm that glutamine synthetase is in the pars recta of the rat proximal tubule. p-Aminohippuric acid uptake impairment and glutamine synthetase activity loss caused by the highest doses of hexachloro-1:3-butadiene and potassium dichromate, respectively, suggests that high doses of segment-specific chemicals may involve other portions of the proximal tubule; in addition, the decrease of glutamine synthetase activity caused by potassium dichromate may be related to the protein content loss.

Assessment of cognitive function in asymptomatic HIV-positive subjects.

This retrospective study aims to assess cognitive involvement in pre-AIDS, not drug abuser subjects and to determine whether CD4 status or disease stage best correlates with cognitive changes that may portend development of ADC. 328 cases were analyzed. No differences in psychometric performance in relation to CDC stage were found. Instead, patients with CD4 < 200/microl performed worse overall, with a statistically significant difference for Digit Symbol, Corsi Test, Block Design and HIVDA Scale. Even if cognitive decline is not evident in the early phase of HIV infection, CD4 count seems the more sensitive early indicator of cognitive changes adequately pointed out by the HIVDA Scale, which could be considered a useful screening tool for cognitive deficit.

Ultrastructure of the germ cells in the testis of matrinxã, Brycon cephalus (Teleostei, Characidae).

This study describes at ultrastructural level the germ cells in the testis of matrinxã (Brycon cephalus) raised in captivity. The specimens 'matrinxã' were maintained in four breeding tanks of 200 m(2), at the Aquaculture Research Center at Vale do Ribeira-CEPAR, from Fishery Institute, in Pariquera-Açu City, São Paulo, Brazil. The samples were collected from March 1994 to February 1996. The testis has been classified as tubular unrestricted spermatogonial type, in which four stages of germ cells can be distinguished as follows: spermatogonia, spermatocytes (primary and secondary); spermatids and spermatozoa.

Microglial nodular encephalitis and ventriculoencephalitis due to cytomegalovirus infection in patients with AIDS: two distinct clinical patterns.

In patients with AIDS, cerebral infection due to cytomegalovirus (CMV) results in two distinct neuropathological patterns: microglial nodular encephalitis (MGNE) and ventriculoencephalitis (VE). In order to identify clinical features to facilitate the differential diagnosis of these two forms of CMV encephalopathy in living patients, we retrospectively reviewed the clinical records of 18 patients with MGNE or VE diagnosed at autopsy. We identified the following clinical features as distinguishing the two encephalopathies: (1) MGNE manifests earlier than VE; (2) the onset of MGNE is acute, whereas the onset of VE is insidious; (3) the onset of MGNE is marked by confusion and delirium, which do not occur in VE; (4) VE is frequently associated with radiculopathy, which is absent in MGNE; and (5) VE is associated with more marked alterations in cerebrospinal fluid (high protein levels and pleocytosis). The early neurological manifestations of MGNE should prompt a search for systemic CMV infection, which may lead to earlier treatment.

Light chain deposition disease neuropathy resembling amyloid neuropathy in a multiple myeloma patient.

A 65-year-old man with IgG lambda multiple myeloma developed severe polyneuropathy with prominent thermal-pain sensory impairment and autonomic failure. Although the clinical presentation suggested amyloid neuropathy, nerve biopsy showed the immunohistochemical and ultrastructural features typical of light chain deposition disease (LCDD). A precise morphologic and clinical description of LCDD neuropathy is given for the first time in the present report.