Search

Background: Below the anterior peritoneal reflection, the anterior rectal wall and mesorectum are separated from the posterior vaginal wall by a virtual rectovaginal space. In this space, the description of a specific and independent rectovaginal septum as a female counterpart of Denonvilliers fascia has been the subject of debate over the years., Objective: The aim of this study is to perform an accurate anatomical study of the rectovaginal area in a cadaveric simulation model of total mesorectal excision to evaluate the possible structures and the dissection planes contained within the rectovaginal space., Design and Setting: This is a cadaveric study performed at the University of Valencia., Patients: The pelvises of 25 formalin-preserved female cadavers were dissected. All the included specimens were sectioned in a midsagittal plane, at the level of the middle axis of the anal canal., Main Outcome Measures: Careful and detailed dissection was performed to visualize the anatomical structures and potential dissection planes during anterior mesorectal dissection in cadavers. Histological sections were made of the posterior vaginal wall., Results: The rectovaginal space contains loose areolar tissue that allows an easy dissection plane distally. A distinct and independent rectovaginal fascia or septum is not present. The existence of 3 layers fused together in the posterior vaginal wall can be identified more or less precisely because of their different coloration. The histological study confirms this macroscopic arrangement of the posterior vaginal wall in 3 layers: the mucosa, the muscular, and the adventitia. An independent rectovaginal septum can be generated only with a splitting of the adventitia., Limitations: The cadaveric pelvic specimens of the oldest donors might have had age-related degeneration., Conclusions: The present anatomical study has shown only a plane of loose areolar tissue between the rectal and vaginal wall. We can conclude that there is no independent fascia or septum in the rectovaginal space. See Video Abstract at http://links.lww.com/DCR/B456. ANATOMÍA QUIRÚRGICA DEL ESPACIO RECTOVAGINAL: ¿EXISTE UN TABIQUE RECTOVAGINAL INDEPENDIENTE O UNA FASCIA DE DENONVILLIERS EN LAS MUJERES: Debajo del reflejo peritoneal anterior, la pared rectal anterior y el mesorrecto están separados de la pared vaginal posterior por un espacio rectovaginal virtual. En este espacio, la descripción de un tabique rectovaginal independiente específico como contraparte femenina de la fascia de Denonvilliers ha sido objeto de debate a lo largo de los años.Realizar un estudio anatómico preciso del área rectovaginal en un modelo de simulación cadavérica de escisión mesorrectal total, con el fin de evaluar las posibles estructuras y los planos de disección contenidos en el espacio rectovaginal.estudio cadavérico realizado en la Universidad de Valencia.Se disecaron las pelvis de 25 cadáveres femeninos conservados en formalina. Todas las muestras incluidas fueron seccionadas en un plano medio sagital, a la altura del eje medio del canal anal.Se llevó a cabo una disección cuidadosa y detallada para visualizar las estructuras anatómicas y los posibles planos de disección durante la disección mesorrectal anterior en cadáveres. Se realizaron cortes histológicos de la pared vaginal posterior.El espacio rectovaginal contiene tejido areolar laxo que permite un plano de disección fácil distalmente. No hay fascia o tabique rectovaginal distinto e independiente. La existencia de tres capas fusionadas en la pared vaginal posterior puede identificarse con mayor o menor precisión debido a su diferente coloración. El estudio histológico confirma esta disposición macroscópica de la pared vaginal posterior en tres capas: la mucosa, la muscular y la adventicia. Un tabique rectovaginal independiente solo se puede generar con una división de la adventicia.Las muestras pélvicas de cadáveres de los donantes más antiguos pueden haber tenido degeneración relacionada con la edad.El estudio anatómico actual solo ha mostrado un plano de tejido areolar laxo entre la pared rectal y vaginal. Podemos concluir que no hay fascia o tabique independiente en el espacio rectovaginal. Consulte Video Resumen en http://links.lww.com/DCR/B456. (Traducción-Dr. Adrian Ortega).

Purpose: We report a very unusual case of variant coronary artery anatomy, discovered during anatomical dissection in a medical school., Methods: The heart from a very advanced age donor was dissected using classic anatomical techniques, Results: The right coronary artery showed a superdominant pattern, extending beyond the crux of the heart and circling the atrioventricular groove almost completely. It followed the usual path of the absent circumflex artery, and ended as a slender branch which almost reached the origin of the anterior interventricular artery., Conclusions: To our knowledge, these are the first reported dissection images of this kind of coronary artery variation. It may have clinical consequences, either leading to more accelerated atherosclerotic changes or causing technical difficulties during cardiac surgery.

Background: Different techniques have been designed to reduce the rate of internal hernia (IH) after laparoscopic bariatric surgery, and mesenteric closure is possibly the most controversial. We propose a laparoscopic Roux-en-Y gastric bypass (LRYGB) procedure without mesenteric closure with several specific technical details to avoid IH. To support this view, we have reviewed the outcome of our LRYGB patients and have carried out an anatomical study on cadavers., Methods: A retrospective observational study was carried out using the Unit's prospective database. The patients selected were those who were operated on for morbid obesity using LRYGB and who presented to the Emergency Unit with symptoms of intestinal obstruction (IO). Data concerning demographics, weight progress, technical details of the surgery, follow-up percentage, morbidity, and mortality were collected. Furthermore, an anatomical model was made in order to recreate the surgery on cadavers., Results: Only 1.6 % of postoperative IO and very few (0.3 %) of IH cases were associated with our technique of LRYGB without mesenteric closure. The anatomical model showed two large potential hernia spaces, but their supramesocolic situation, the orientation of the bowel loops, leaving the mesentery and omentum undivided and the antecolic passage of the alimentary limb made intestinal herniation difficult even though the mesenteric spaces were not closed., Conclusions: With a proper technique, the closure of mesenteric spaces after a LRYGB is not essential to avoid postoperative IH in bariatric patients, as evidenced in an anatomical model.

Assessment of ocular dimensions is essential for ophthalmic surgeons because these values must be determined before scheduling excimer laser refractive and cataract surgeries. Dry eye seems to affect central corneal thickness (CCT) values, but it is not clear if it affects anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD) and axial length values. Following on from this, we measured the CCT, ACD, LT, VCD and axial length of 64 healthy eyes (51.20%) and 61 dry eyes (48.80%). CCT was measured with scanning-slit corneal topography (Orbscan Topography System II, Orbscan, Inc., Salt Lake City, UT, USA) and ACD, LT, VCD and axial length with a 10-MHz A-mode ultrasound device (Compuscan; Storz, St. Louis, MO, USA). There were no significant differences in ACD (P=0.588), LT (P=0.739), VCD (P=0.568) and axial length (P=0.199) between normal and dry eyes. Nevertheless, the differences in CCT between normal (549+/-34 microm) and dry eyes (527+/-30 microm) were significant (P<0.001). In sum, it seems that only the CCT values are significantly lower in subjects with dry eye.

Purpose: This study was designed to analyze the differences in central corneal thickness values determined with noncontact specular microscopy and scanning-slit corneal topography. The measurements were performed on the same eye., Methods: We analyzed the central corneal thickness values of 93 patients (n = 93) by means of noncontact specular microscopy (Topcon SP-2000P noncontact specular microscope, Topcon Corp., Tokyo, Japan) and scanning-slit corneal topography (Orbscan Topography System II, Orbscan Inc., Salt Lake City, UT). One experienced physician performed 3 consecutive central corneal thickness measurements with both devices., Results: The central corneal thickness values obtained by means of Orbscan pachymetry were 17 +/- 2.7 (range, 12-24) microm greater. A significant correlation was observed between scanning-slit corneal topography and noncontact specular microscopy (Pearson correlation coefficient, r = 0.976; P < 0.001)., Conclusions: Researchers should know of the existence of this difference between noncontact specular microscopy and Orbscan pachymetry when interpreting central corneal thickness values.

Purpose: To analyze the corneal endothelial cell density in healthy adult emmetropic subjects., Methods: We analyzed the corneal endothelial cell density of a group made up of 225 emmetropic subjects (n=225). As age-matched control groups we analyzed two other groups, one made up of myopic subjects (n=209) and the other made up of hyperopic subjects (n=203). We recorded the mean of three consecutive measurements of the corneal endothelial cell density using the Topcon SP-2000P non-contact specular microscope (Topcon Corp., Tokyo, Japan)., Results: The mean age was 38.6+/-11.8 years, 40.7+/-12.2 years, and 39.2+/-10.5 years for emmetropic, myopic and hyperopic subjects respectively (p=0.994). No significant differences (p=0.920) in endothelial cell density values were found between emmetropic (2985+/-245 cells/mm2), myopic (2936+/-258 cells/mm2) and hyperopic eyes (2946+/-253 cells/mm2). Lower corneal endothelial cell density values were found in older emmetropic (p<0.001), myopic (p<0.001), and hyperopic subjects (p<0.001). A significant correlation between endothelial cell density and age was found in emmetropic (r=-0.958; p<0.001), myopic (r= -0.954; p<0.001) and hyperopic subjects (r= -0.948; p<0.001)., Conclusions: In healthy emmetropic subjects there is a reduction in corneal endothelial cell density with age although there are no differences in corneal endothelial cell density values between emmetropic, myopic and hyperopic subjects.

Purpose: To study and compare the corneal thickness values of postmenopausal women with dry eye and postmenopausal women without dry eye., Methods: The corneal thickness value of 30 postmenopausal women with dry eye (dry eye group; aged 52 to 55 years) and 32 postmenopausal women without dry eye (normal group; aged 51 to 55 years) was analyzed with the Orbscan Topography System II. Each woman underwent a tear breakup test, the Schirmer test, fluorescein staining of the cornea, and an analysis of the meibomian gland by slit lamp before corneal thickness measurement. The statistical analysis was performed by means of the unpaired Student t test., Results: The mean corneal thickness value was significantly decreased in postmenopausal women with dry eye (P < 0.001 at each corneal location). The central cornea had the thinnest mean values in dry eyes and normal eyes (533.10 +/- 4.74 microm and 547.63 +/- 15.11 microm, respectively), whereas superonasal cornea had thicker mean values in both groups (632.43 +/- 6.11 microm and 648.78 +/- 14.98 microm in dry eye and normal eyes, respectively)., Conclusions: Postmenopausal women with dry eye have lower corneal thickness values than postmenopausal women without dry eye. Special care must be taken with these reduced corneal thickness values when selecting postmenopausal women for surgery involving corneal photoablation.

Purpose: To study the corneal thickness of young emmetropic subjects., Methods: One thousand eyes of 1000 young healthy emmetropic subjects were analyzed with the Orbscan Topography System II (Orbscan, Inc, Salt Lake City, UT) from January 2001 to May 2003. The age of the subjects ranged from 20 to 30 years old (mean +/- SD = 27.12 +/- 2.86). The mean of 5 consecutive measurements of the corneal thickness in the center of the cornea and at temporal, superotemporal, inferotemporal, nasal, inferonasal, and superonasal cornea were recorded., Results: The corneal thickness at the following areas ranged as follows: 518 to 589 microm center; 603 to 678 microm nasal; 620 to 689 microm superonasal; 600 to 669 microm inferonasal; 571 to 639 microm temporal; 601 to 669 microm superotemporal; and 572 to 647 microm inferotemporal. In each individual the difference between the central thickness and the maximum paracentral thickness ranged from 85 to 107 microm (mean +/- SD, 99.21 +/- 3.80). The difference between the central thickness and the minimum paracentral thickness ranged from 36 to 59 microm (48.97 +/- 4.23 microm). The difference between the minimum paracentral corneal thickness and the maximum paracentral corneal thickness ranged from 37 to 58 microm (50.24 +/- 4.30). The tonometry was statistically correlated with the corneal thickness (P < 0.05 at each corneal location analyzed)., Conclusions: In emmetropic corneas the difference between the minimum paracentral thickness and the maximum paracentral thickness was similar to the difference between the central thickness and the minimum paracentral thickness.

The gracilis muscle has been used extensively in reconstructive surgery, based on the proximal dominant pedicle. In the literature, little attention has been paid to the secondary distal pedicles. The distribution of the secondary pedicles of the gracilis muscle was investigated in 20 cadaver thighs. The mean number of secondary pedicles was 2.2 (range, two to three). When two pedicles were present-the most common situation-they were located at a mean distance of 12.4 and 17.5 cm from the knee joint line. The most proximal secondary pedicle was injected with barium sulfate in five specimens, and constant and abundant connections with the main pedicle were noted. A series of seven clinical cases of segmental gracilis free muscle flaps based on a secondary pedicle is reported. The flaps were successfully transferred to reconstruct traumatic defects of limited size, with one case of partial necrosis caused by a technical error. The morbidity of this flap is minimal, the scar is well hidden, the muscle need not be sacrificed, elevation is fast and straightforward under tourniquet control, and the pedicle is sizable. This flap should be considered a viable option when a small, straightforward free flap is needed.

The nucleus incertus is located caudal to the dorsal raphe and medial to the dorsal tegmentum. It is composed of a pars compacta and a pars dissipata and contains acetylcholinesterase, glutamic acid decarboxylase, and cholecystokinin-positive somata. In the present study, anterograde tracer injections in the nucleus incertus resulted in terminal-like labeling in the perirhinal cortex and the dorsal endopyriform nucleus, the hippocampus, the medial septum diagonal band complex, lateral and triangular septum medial amygdala, the intralaminar thalamic nuclei, and the lateral habenula. The hypothalamus contained dense plexuses of fibers in the medial forebrain bundle that spread in nearly all nuclei. Labeling in the suprachiasmatic nucleus filled specifically the ventral half. In the midbrain, labeled fibers were observed in the interpeduncular nuclei, ventral tegmental area, periaqueductal gray, superior colliculus, pericentral inferior colliculus, pretectal area, the raphe nuclei, and the nucleus reticularis pontis oralis. Retrograde tracer injections were made in areas reached by anterogradely labeled fibers including the medial prefrontal cortex, hippocampus, amygdala, habenula, nucleus reuniens, superior colliculus, periaqueductal gray, and interpeduncular nuclei. All these injections gave rise to retrograde labeling in the nucleus incertus but not in the dorsal tegmental nucleus. These data led us to conclude that there is a system of ascending projections arising from the nucleus incertus to the median raphe, mammillary complex, hypothalamus, lateral habenula, nucleus reuniens, amygdala, entorhinal cortex, medial septum, and hippocampus. Many of the targets of the nucleus incertus were involved in arousal mechanisms including the synchronization and desynchronization of the theta rhythm., (Copyright 2003 Wiley-Liss, Inc.)

Background: Growth factors seem to play a major role in corneal wound healing and TGF-beta seems to be associated with abnormal healing after corneal surgical procedures. Few studies have analysed the role of NGF and TGF-beta on corneal wound healing during pregnancy. The aim of the present study was to create an animal model to evaluate the expression of NGF and TGF-betas during corneal wound healing in two groups: control and pregnant rats., Methods: Corneal mRNA for NGF and the three isoforms of TGF-beta were analysed by RT-PCR, in a time-course experiment on different days after epithelial wounding (2, 7, 14 days) in pregnant and control groups, Results: The results show high corneal mRNA expression for NGF and TGF-beta1 without any variation throughout the healing process or pregnancy evolution. However, we detected a different expression of corneal mRNAs for TGF-beta2 and TGF-beta3 in the control group. This data was not detected in the pregnant group., Discussion: Our results suggested that pregnancy could have a relevant role on TGF-beta2 and TGF-beta3 mRNA expression during the corneal wound healing process. Additional research should be performed to corroborate these findings.

Synaptic bodies (SB) are ultrastructural organelles observed in the pinealocytes of mammals. According to its shape, they have been classified into synaptic ribbons (SR), synaptic spherules (SS), and intermediate synaptic bodies (ISB). They have been related to the melatonin regulation and production mechanisms of the pineal gland. Circadian and circannual fluctuations of both melatonin and SB have been reported. The possibility that other external factors, apart from light-dark or seasonal cycles, might influence pineal function has been suggested. We studied the evolution of the number of SB and serum melatonin levels not only during light-dark and seasonal phases but also during lunar cycles. Forty male wistar rats were used. Experiment was first carried out in winter and repeated identically in spring. Each season, one group of animals was killed during the new-moon days and a second group during the full-moon days: half of both groups in the photophase and the other half in the scotophase. The number of SB was measured at electron microscopic level whereas serum melatonin levels were determined by radioimmunoassay techniques. Main results showed that SR number and serum melatonin levels were higher during scotophases, winter and full-moon days. The SS only showed a light predominance during winter, whereas predominance of the ISB was found only during the scotophases. These results support the influence of the photophasic factors on the SR and ISB variations. In the case of the SS the influence of the lunar cycles is always dependent on the other factors. Finally, the serum level of melatonin is clearly influenced by the photophasic rhythms and the seasonal periods but not by the lunar cycles.

Morphological and physiological studies suggest a possible division of the pineal parenchyma into an external or "cortical" and another central or "medullar" layer. We have studied the possible influence of the light/dark, seasonal and lunar cycles on the nuclear size of the pinealocytes of the rat in both the hypothetical "cortical" and "medullar" layers. Forty male Wistar rats were used. Experiment was carried out in two seasons, winter and spring, two lunar phases, full moon and new moon, and the two circadian phases, photophase and scotophase. The nuclear volume of the pinealocytes, calculated from the Jacobj's formula, was the karyometric parameter used as measurement of the nuclear size. Main results showed that nuclear volume of the cortical pinealocytes was greater than that of the medullar pinealocytes only during the photophases of winter new-moon days and spring full moon days, whereas in all the remaining situations, the greater nuclear sizes were found in the pinealocytes of the medullar layer. These results support the existence of independent morphological variations of the pinealocyte in the central and peripheral zones of the pineal gland.

The pattern of c-Fos expression was mapped in the adult rat's brain following unilateral cochlear lesions. In normal and cochlear lesioned rats, c-Fos expression was induced with sound stimuli. Acoustic stimulation consisted of pulses of four tones. An additional control group consisted of non-stimulated rats. In the cochlear nuclei (CN), c-Fos activation was scarce in isolated rats and increased strongly following sound stimulation. Following unilateral cochlear lesion, acoustically driven expression was decreased in all CN in both the lesioned and the untreated sides. The ventromedial periolivary nucleus and the rostral periolivary nucleus showed c-Fos activation in isolated conditions and were strongly activated following sound stimulation. The rest of the superior olivary complex showed no c-Fos activation in isolated rats and a weak activation following sound stimulation. Following unilateral cochlear lesions, acoustically driven expression was decreased in some, but not all superior olivary nuclei in both the lesioned and the untreated sides. In the lateral lemniscus complex, c-Fos activation was scarce in isolated rats and increased strongly after stimulation. Following unilateral cochlear lesion, acoustically driven expression decreased bilaterally in all nuclei. We have found that unilateral inner ear lesions lead to bilateral impairment of the capability of acoustic pathway neurons, to being c-Fos-activated following sound stimulation.

The medial sural artery supplies the medial gastrocnemius muscle and sends perforating branches to the skin. The possible use of these musculocutaneous perforators as the source of a perforator-based free flap was investigated in cadavers. Ten legs were dissected, and the topography of significant perforating musculocutaneous vessels on both the medial and the lateral gastrocnemius muscles was recorded. A mean of 2.2 perforators (range, 1 to 4) was noted over the medial gastrocnemius muscle, whereas in only 20 percent of the specimens was a perforator of moderate size noted over the lateral gastrocnemius muscle. The perforating vessels from the medial sural artery clustered about 9 to 18 cm from the popliteal crease. When two perforators were present (the most frequent case), the perforators were located at a mean of 11.8 cm (range, 8.5 to 15 cm) and 17 cm (range, 15 to 19 cm) from the popliteal crease. A series of six successful clinical cases is reported, including five free flaps and one pedicled flap for ipsilateral lower-leg and foot reconstruction. The dissection is somewhat tedious, but the vascular pedicle can be considerably long and of suitable caliber. Donor-site morbidity was minimal because the muscle was not included in the flap. Although the present series is short, it seems that the medial sural artery perforator flap can be a useful flap for free and pedicled transfer in lower-limb reconstruction.

The chemoarchitecture of the periaqueductal gray has been extensively studied, based on acetylcholinesterase reaction and comparing it to other chemical markers. We have divided the periaqueductal gray into four main longitudinal columns, namely dorsomedial, dorsolateral, lateral and ventrolateral. We also identified the dorsal midline column, the supraoculomotor cap and the juxta-aqueductal ring. The acetylcholinesterase gave rise to a strong reaction in the outer half of the lateral column, the outer half of the dorsomedial column, the supraoculomotor cap and the ventral half of the juxta-aqueductal ring. This labeling was in part complementary to that of the NADPH diaphorase and allowed the lateral column to be differentiated from the ventrolateral column. However, the inner half of both lateral and ventrolateral columns displayed the same chemical properties including acetylcholinesterase, tyrosine hydroxilase and serotonin. Thus, from the chemical view, these inner halves should be considered as one different region. Finally, the juxta-aqueductal ring was composed of two clearly different halves, i.e. dorsal and ventral. The dorsal half did not show any clear differences from the above columns and was negative for acetylcholinesterase, NADPH diaphorase and tyrosine hydroxilase, while the ventral half was clearly different from the lateral and ventrolateral columns and displayed a positive reaction to all those chemical markers. From these results, we strongly suggest the use of acetylcholinesterase histochemistry as a tool for accurate parcellation of the periaqueductal gray.

In the mammalian pineal gland, synaptic bodies (SBs) are poorly understood organelles. Previous studies in rabbits have shown that the organelles are rather heterogeneous in shape, are few in number during the day and increase in number at night. No studies are currently available on seasonal changes in this species and it is unknown whether the biological rhythms are identical in the proximal, intermediate and distal parts of the elongated pineal. To this end, a study was made of 84 rabbits kept under natural lighting conditions to examine numerical variations of the different types of SBs in the proximal, intermediate and distal regions of pineal glands procured at different timepoints of a 24-hour cycle and in each of the four annual seasons. In the present study, rod-like, sphere-like, ovoid, rectangular and triangular SB profiles were distinguished; the first two types being the most abundant. In addition to the well-known circadian changes, with low numbers of SB profiles during the day and high numbers at night, we found pronounced season-related differences as well as differences related to pineal regions. In autumn and winter, nighttime SR profile numbers were significantly higher than in spring and summer. With respect to regional differences it was found that the amplitude of the circadian rhythm increased in a proximo-distal direction in the gland. In autumn the strongly enhanced nocturnal increase was restricted to the distal region of the gland, whereas in winter it was seen in both the distal and the intermediate regions. The regional differences are probably related to the fact that the postganglionic sympathetic fibres, which regulate pineal function, enter the gland distally and proceed rostrally to the proximal region. Taken together, the results show that day- and nightlength are structurally coded in the pineal gland by means of SB numbers. Provided the SBs of the mammalian pineal gland are involved in synaptic processes, the results suggest that synaptic processes are enhanced at night as well as in autumn and winter.

Chronic ethanol feeding promotes oxidative stress in rat peripheral nerve. Malondialdehyde, a lipid peroxidation product, content increases in sciatic nerves of rats fed an ethanol-containing diet, when compared with pair-fed animals. Moreover, glutathione content and glutathione peroxidase activity in this same tissue decrease in ethanol-fed vs. pair-fed rats. S-Adenosyl-L-methionine and N-acetyl-L-cysteine, both with possible therapeutic action on alcoholism, were tested in this animal model. Only N-acetyl-L-cysteine was able to normalize malondialdehyde content and to restore glutathione content and glutathione peroxidase activity, to values not significantly different from those of sciatic nerves from pair-fed animals. The reasons for the different effect of both substances tested is also discussed.

The pattern of expression of the proto-oncogene c-fos was mapped in the auditory pathway of Wistar rats kept in three different experimental conditions: a) a dark, soundproofed room; b) with exposure to usual environmental laboratory noise, and c) with exposure to wide-band noise. Under control conditions (a and b), scattered labeled neurons were found in the ventral periolivary nucleus, lateral lemniscus nuclei, inferior colliculus, medial nucleus of the medial geniculate body, and in three divisions of the temporal auditory cortex. Sound stimulation (c) increased the number of fos-like-immunoreactive (FLI) nuclei in all the auditory pathway structures. FLI nuclei were strong in the dorsal cochlear nucleus, anterior and posterior ventral cochlear nuclei, all the superior olivary complex nuclei, lateral lemniscus nuclei, all areas of the inferior colliculus, medial geniculate body, and the three temporal auditory areas, which showed a barrel pattern. Comparison of these results with the literature indicated that fos activation is not merely a sign of transitory neural activation, but a long-term neural processing pathway that is conditioned by factors such as the frequency, intensity, duration, and direction of the auditory stimulus.

The distribution of c-fos proto-oncogene expression has been studied in the periaqueductal grey matter (PAG) of non-intentional-stimulated rats by immunohistochemistry. A mean number of 53 +/- 9 Fos-like immunoreactive cells per hemiPAG, distributed into three groups, dorsolateral, lateral and ventrolateral, was found. The dorsolateral and the lateral groups appeared along the entire rostrocaudal PAG, whereas the ventrolateral group appeared only in the caudal half. These results reveal new data on the number and extent of the longitudinal columns within the hypothetical organization of the PAG. They also indicate a continuous activation of a significant population of neurones in the PAG, in agreement with the suggested role of the PAG in the modulation of internal information.

Thirty-six male Wistar rats (225g average b.w.) were studied after direct He-Ne laser irradiation (632.8 nm, 5 mW) of the surgically-exposed pineal gland. Total irradiation time was 5 minutes, with rest intervals of 1 minute for every minute of irradiation. The animals were sacrificed in groups of 4 (controls, irradiated animals and sham-operated rats--i.e., craniotomy without irradiation) on days 3, 7 and 10 postirradiation. A significant increase was seen (p < 0.0001) in the medullary and cortical karyometric indices of the pineal body in all experimental, control and sham-operated animals. The increase was greatest (over 50%) on day 3 postirradiation among the experimental animals, with respect to the control and sham-operated groups. A progressive and significant decrease in karyometric index (p < 0.05) was in turn observed on days 7 and 10 postirradiation, although the values remained higher than among the controls. Ultrastructurally, there were cytoplasmic signs of an increase in metabolic activity in the experimental animals on days 3 and 7, followed by a decrease in activity by day 10 with the appearance of numerous lipid droplets, pericanallicular dark cells and mesoglial cells. We suggest that laser irradiation stimulates cortical and medullary pinealocytes, followed by a decreased effect at day 10 postirradiation. The effect of laser light is in turn determined by experimental action and the duration of exposure.

Circadian and seasonal variations were observed in the karyometric index of pinealocytes in the cortical and medullary regions of the distal pineal body. The study involved 70 Wistar rats over a 24-hour interval (0:6, 10:00, 14:00, 18:00, 22:00, 02:00, 06:00 h) during two natural photoluminous periods, i.e. late summer (Long photoperiod) and Winter (Short photoperiod). The results show a difference between the high and low points of both photoperiods. Cortico-medullary differences are found at different times of day during long photoperiod (0:6; 10:00; 14:00 and 18:00 h.) and short photoperiod (14:00; 22:00 and 02:00 h.). The variance analyses between nuclear volume and point-time and between nuclear volume, point-time and location are significative. A high correlation between circadian rhythms and volumetric variations in both layers and photoperiod are found. The results also show significant differences in cortico-medullary karyometric indices between both seasons as well as between the diurnal and nocturnal hours of both photoperiods. It is suggested that the pineal body of the rat is influenced by circadian and seasonal photoperiod and may have groups of cells with different functional characteristics, depending on their location within the gland.

We have realized a statistic study about "Karyometric Index" in the hair cells of the Corti organ of the albino Wistar rat [correction of guinea pig] in thirty of these animals; after in vivo fixation. The Karyometric Index variations are a good indicator of the cellular basic functional activity. Therefore we tried to clarify if the their cells are or not resembling to other cellular types with the functional circadian circles as well as if they present it or not in their basic functionalism, as they are also included in the "Endocrine Difusse System" and the "Paraneuron" concepts.

A comparative statistical analysis of "synaptic ribbons" evolution over a 24 hour period during two different photoluminous seasons (September, and winter) is carried out. Seventy male rats were used. Statistical analysis involved the Kolmogorov-Smirnov test, variance analysis, the Student t-test and Pearson's correlation test. The results show that "synaptic ribbons" evolve during the circadian phase and through two different seasons, with a clear and marked influence of point-time (p < 0.0001) and season (p < 0.0001).

In continuation of earlier studies, we have investigated the influence of 52-Gs (50-Hz) magnetic fields on the evolution of pinealocyte 'synaptic ribbons' and serum melatonin levels in rats, following 30 min daily exposure. The animals were sacrificed after 1, 3, 7, 15 and 21 days. A significant decrease in the number of synaptic ribbons was observed after 15 and 21 days, together with a significant drop in serum melatonin concentrations after 15 days. The mediating role of the retina in these modifications and magnetic field effects is discussed.

We have realized a morphometric and statistic study about "synaptic ribbons" in the hair cells of the Corti organ. These structures are pinealocyte features with remarkable and demonstrated circadian circle and also the main parameter to measure the pineal function. Therefore we tried to clarify if the hair cells are or not resembling to other cellular types with the functional circadian circles, as well as if they present it or not in their basic function , as they are also included in the "endocrine diffuse system" and "the paraneuron" concepts.

Seventy Wistar rats are used to study the changes in pineal intercellular canaliculi over a 21-hour period and for two different photoperiods (pre-autumn, first week of September, and winter, first week of February). The study considers these changes at pineal body, cortical and medullar level separately, and compares the values obtained. The results show variations in canalicular surface at different point times (10:00, 14:00, 18:00) and for both photoperiods. The variations are found to favour the cortical layer, and are also observed between nocturnal and diurnal hours. Canalicular surface to greater during the diurnal hours of both photoperiods. Interesting histological findings are described that suggest an important function of the intercellular canaliculi in pineal gland metabolic exchange.

A study is made of the pinealocyte karyometric index and pineal gland ultrastructure in 60 male Wistar rats (250 g on average) sacrificed 1, 3, 7, 15 and 21 days after commencing application of a magnetic field (intensity, 52 Gauss; frequency, 50 Hz) for a period of 30 minutes daily. A progressive decrease was observed in karyometric index corresponding to both the peripheral and central gland region, with a significant difference between the two after 3 and 7 days (p less than 0.0001). A significant increase in lipid activity was also seen during the same period. Pineal gland structural organization during the experimental period is evaluated at both light and electron microscope level.

We present the results obtained in the adrenal gland of white rats (average weight 220 g) following irradiation of the pineal gland with laser light. Irradiation was carried out with a 5 mW Politec 750 Helium-Neon laser. Total irradiation time was 5 min, with rest intervals of 1 min for every minute of irradiation. Pineal gland irradiation was done under "open sky", i.e., directly at the gland. The effects of the suprarenal gland were studied 3, 7 and 10 d postirradiation. Morphological signs of an increasing activity have been observed in all layers of the cortex and in the medulla of the gland. The highest increase was found 7 d after irradiation in the fascicular zone and in the medulla, and after 3 d in the glomerular and reticular zone. We suggest that laser light induces an inhibitory effect observed at the suprarenal gland. This effect is similar to that found following pinealectomy, showing once again that the pineal gland exerts control on the suprarenal gland, mediated by luminous stimuli.