'Bone map' for a safe placement of miniscrews generated by computed tomography.

OBJECTIVES: The aim of this manuscript is to provide a bone map that can be used as a general guide to determine the areas where miniscrews can be safely anchored. MATERIALS AND METHODS: Twenty-one computed tomographies (CTs) of maxilla and mandible were taken by the imaging centre ORTOSCAN and two measures were taken: --first, the interradicular space in the mesiodistal plane of the maxillary and mandible teeth with slices taken at 3, 6, and 9 mm from the alveolar crest, in the palatine and vestibular slices, --second, the interradicular space in the vestibular-lingual direction. RESULTS: We can see that the greatest amount of mesiodistal bone is between the first and second inferior molars on the vestibular side and between the second and first inferior molars on the lingual side, whereas the least amount of bone on the mesiodistal plane is between the inferior incisors on the vestibular side. To determine the length of the miniscrew, we must take into account that the greatest amount of vestibular-lingual bone is between the first and second inferior molar, whereas the least amount is between the central and lateral inferior incisors. CONCLUSIONS: Mesiodistal values in vestibular are those that must be considered when inserting the microscrew so as not to damage the dental tissue. Mesiodistal measurements taken in palatal-lingual do not present problems when inserting microscrews.

[The noninvasive study of cerebral veins and dural sinuses: comparison of two MR angiography techniques]. / Estudio no invasivo de las venas cerebrales y los senos durales: comparación de dos técnicas de angiografía con resonancia magnética.

OBJECTIVE: To evaluate MR venography with bolus injection of intravenous contrast and elliptical filling of the K space, using three-dimensional fast spoiled gradient-echo (3D-FSPGR) sequences, and to compare it to the technique most frequently employed in the study of cerebral veins and dural sinuses, which is two-dimensional time-of-flight (2D-TOF) MR venography. MATERIAL AND METHODS: Source images, multiplanar reconstructions, and maximum intensity projections (MIP) were obtained using both 2D-TOF venography and contrasted-enhanced 3D-FSPGR venography in 20 healthy volunteers. Two radiologists independently evaluated both techniques for the visualization of twenty-one predefined venous structures, classifying the depiction as completely visible, partially visible, or not visible. RESULTS: The predefined venous structures were completely visible in 795 of 840 (94.6%) of the evaluations of contrast-enhanced 3D-FSPGR images versus 682 of 840 (81.1%) evaluations of 2D-TOF venography images. In the major dural sinuses, visualization was complete in 99.4% of the readings of contrast-enhanced 3D-FSPGR images versus 81% in the readings of the 2D-TOF images. CONCLUSION: 3D-FSPGR with elliptical filling of the K space and bolus injection of contrast material provides higher quality images of the intracranial venous system than those obtained using 2D-TOF sequences.

US drinking water: fluoridation knowledge level of water plant operators.

OBJECTIVES: We determined the knowledge level of water plant operators who fluoridate drinking water, and we compared small and large water plants. METHODS: A pretested survey was sent to 2,381 water plant operators in 12 states that adjust the fluoride concentration of drinking water. A z-test for proportion was used to test for statistical difference between small and large plants at alpha = 0.05. Small water plants were those treating less than 1 million gallons of water daily. RESULTS: Eight hundred small and 480 large water plant operators responded, resulting in a response rate of 54 percent. Two-thirds of water plant operators correctly identified the optimal fluoride level, but more than 20 percent used a poor source for choosing the optimal level. Only one-fourth of operators were able to maintain the fluoride concentration to within 0.1 mg/L of the optimal concentration. A significantly greater proportion of operators at large water plants than at small water plants reported that they were able to maintain a fluoride concentration to within 0.1 mg/L of the optimal concentration (33.5% vs 21.3%, z = 4.74, P < .05). CONCLUSIONS: Although most operators correctly identified the optimal fluoride level, small water plant operators were less likely to use accurate reasoning for choosing that level and in maintaining fluoride concentrations within 0.1 mg/L of that level than large water plant operators.

[Adult congenital anomalies of the coronary arteries described over 31 years of angiographic studies in the Asturias Principality: main angiographic and clinical characteristics]. / Anomalías congénitas de las arterias coronarias del adulto descritas en 31 años de estudios coronariográficos en el Principado de Asturias: principales características angiográficas y clínicas.

OBJECTIVE: The aim of this study was to determine the incidence of adult congenital anomalies of the coronary arteries over 31 years of angiographic studies, describing their angiographic and clinical characteristics. The results have been compared with the main series published. METHODS: The diagnostic angiographic reports done in the Principado de Asturias from 1968 to 1999 are reviewed. In those in which a congenital anomaly was diagnosed, the clinical report and the angiography were studied. The initial course of the anomaly was defined following angiographic criteria. RESULTS: Thirteen thousand five hundred reports were reviewed describing 75 patients with 75 anomalies (0.5%) including: anomalous origin of the left circumflex coronary artery (n = 24), coronary artery fistulae (n = 21), both coronary arteries arising from the left coronary sinus (n = 15), single coronary arteries (n = 6), both coronary arteries arising from the right coronary sinus (n = 2), separated origin of anterior descending and left circumflex coronary arteries (n = 3), anterior descending artery arising from the right coronary sinus (n = 2), and others (n = 1). Angiographic studies were done because of: angina (59%), dysnea (25%), atypical chest pain (7%), syncope (3%), dizziness (3%) and palpitations (3%). The initial course was retroaortic in all the circumflex arteries, interarterial in the right coronaries, anterior in the anterior descending arteries and retroaortic, septal and combined, in the left coronaries. CONCLUSIONS: Adult congenital anomalies of the coronary arteries are not very common and are usually casual findings of diagnostic angiographic studies. Left circumflex coronary artery anomalies are the most frequently diagnosed.

In vivo bromodeoxyuridine (BrdU)-labelling index of rat thymus: influence of different BrdU doses and exposure times as analyzed both in tissue sections and in single cell suspensions.

Tissue sections and single cell suspensions of rat thymus were analyzed by flow and image cytometry to study the effects of different doses of bromodeoxyuridine (BrdU) (10, 50 and 100 mg/kg and different labelling periods (15, 30 and 60 min) on the BrdU-labelling index. The proportions of BrdU-labelled cells, as analyzed by flow cytometry, were similar in the different groups of our study. However, the quality of the results was not exactly the same, since when the BrdU dose decreased, the separation between BrdU-positive S-phase cells and both the G0/G1 and the G2/M BrdU-negative cells on a DNA/BrdU histogram became less clear. On the other hand, the proportion of BrdU-labelled cells in tissue sections was greater in the groups of animals that received doses of 100 mg/kg and were killed 15, 30 or 60 min later than in the sections obtained from the remaining groups. Our results show that both dose and exposure time to BrdU may influence the final results when cell proliferation is assessed, the variations obtained clearly depending on the technique used for the immunological detection of BrdU-positive S-phase cells.

Changes in hypothalamic met-enkephalin levels of rats induced by painful stimulation and morphine treatment.

The possible influence of painful stimulation and morphine analgesia on hypothalamic met-enkephalin levels, and the possible correlation between this biochemical parameter and animal behaviour was studied. The results indicate that both painful stimulation and morphine treatment induce an increase in hypothalamic metenkephalin. On the other hand, naloxone did not cause any variation. In animals submitted to painful stimulus, morphine treatment induced a decrease in hypothalamic met-enkephalin levels. Finally, when both morphine and naloxone were administrated before nociceptive stimulation, much higher levels were measured. There was no correlation between the level of hypothalamic met-enkephalin and the pain rating.

Immunohistochemical localization of epidermal growth factor and its receptor during odontogenesis in the rat.

The expression of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFr) in developing teeth has been immunohistochemically studied in rat embryos (E-16 to E-21). Both EGF and EGFr showed a similar pattern of distribution. A very weak immunostaining was observed in the dental germ cells during the bud, cap, and bell teeth stages, as well as in few ectomesenchymal cells. In developed, but not erupted teeth, a moderate immunoreactivity for EGF and EGFr was present in the odontoblasts, in the ameloblasts and in the internal epithelial cells, but it was stronger in the dentine. In addition, the presence of EGF/EGFr was also observed in the intercalated ducts of salivary glands, primarily the submaxillary gland, in the maxillary bone cells, and in the cells of the peripheral and central nervous system. These results suggest that EGF has little or no effect during the early periods of tooth differentiation, whereas it is probably involved in the production of dentine. Moreover, EGF/EGFr seem to participate in the maturation and differentiation of other embryonic tissues such as tissues of the nervous system and bone.

Expression of thyroglobulin gene in maternal and fetal thyroid in rats.

The relationship between the changes in thyroglobulin (Tg) mRNA and Tg proteins during thyroid development in the fetus and in maternal thyroid glands during gestation and lactation is studied. While the appearance of Tg mRNA (fetal day 15) showed good temporal correlation with that of 12S Tg, no 19S Tg could be detected until 3 days later. The 12S Tg was the predominant protein on days 18 and 19 of gestation in the fetus, while 19S Tg was the predominant protein on fetal days 21-22 and during the postnatal period in the offspring; by the 20th postnatal day, the 19S Tg content per gland was 4 times the amount of 12S (155 vs. 37 micrograms/gland; P less than 0.001). The 19S iodine content in the fetus was the same as that in 12S up to the 21st day of gestation, except for lower values on day 18. From fetal day 22 and through the postnatal period, the iodine content in 19S was 1.6-5.9 times greater than that in 12S. Therefore, the ratio of atoms of iodine per mol Tg during the experimental period changed from 0.75 to 19.5 for 19S and from 0.72 to 7.2 for 12S. The levels of all of the iodoamino acids were low on fetal days 17-19, after which they increased at different rates for each protein. The greatest increase in monoiodotyrosine and T3 corresponded to 12S, while diiodotyrosine and especially T4 showed a greater increase in 19S than in 12S Tg; 20 days after birth, the T4 content in 19S was about 3 times greater than that in 12S Tg. The soluble thyroid proteins from pregnant, lactating, and nonpregnant female controls contained a main protein, 19S, and a smaller amount of 27S. Both 19S Tg and 19S iodine contents were already lower than those in nonpregnant rats at 14 days of pregnancy, and the levels continued to decrease during the experimental period. In contrast, the 27S Tg and 27S iodine levels remained constant and similar to nonpregnant values. Surprisingly, a decrease in the level of Tg mRNA was observed during pregnancy and lactation. We have no explanation for the dramatic decrease in Tg mRNA during the last days of pregnancy. Further studies should help to elucidate the mechanism responsible for the changes in Tg gene expression in the thyroids of pregnant and lactating rats.

Ultrastructural, immunocytochemical and morphometric studies of pituitary prolactin cells after chronic administration of met-enkephalin.

The effects of chronic administration of met-enkephalin (40 micrograms/day, for 20 days) on the pituitary prolactin cells of Wistar male rats were studied at the light (PAP-immunohistochemical for PRL demonstration technique) and electron microscopy levels. The D. CIRCLE (mean diameter), D. MAX (maximum diameter) and FORM PE (circular factor of form; irregularity degree) form secretory granules, as well as their percent distribution, were also evaluated. The cellular alterations were variable. Most prolactin cells showed an increase in immunohistochemical reaction. At the electron microscope level the prolactin cells showed an enlargement and swelling of the RER and Golgi apparatus. The secretory granules were bigger and more spherical in experimental than in untreated and control animals. A number of cells showed a variable number of cytoplasmic vacuoles or a large central vacuole formed from dilated RER-cisternae. The authors discuss the possible mechanism whereby met-enkephalin exerts a control on prolactin cells.

Study of the rat TSH-producing cells after met-enkephalin treatment: effects of dopamine antagonists.

The effects of single and repeated doses of met-enkephalin (Met-E) on the ultrastructure and TSH-like immunoreactivity (IR) of pituitary TSH-producing cells, and TSH plasma levels in male rats and the influence of pretreatment with a dopamine antagonist, haloperidol, on these, were evaluated. Both acute and repeated Met-E administration produced changes in TSH cells consisting of: an increase in TSH-like IR, enlargement and dilation of RER and Golgi apparatus, size-increase of secretory granules, and the presence of a variable number of cytoplasmic vacuoles. The ultrastructural changes were more evident in the chronically treated animals, whereas no differences were found in IR-intensity between both Met-E treated groups. Haloperidol alone modifies neither ultrastructure nor TSH-like IR of TSH producing cells, but it prevented the Met-E produced changes. On the other hand, Met-E treatment resulted in a decrease of TSH plasma levels, but being significant only in the acutely injected animals. No variations were produced by haloperidol alone, but it prevented the decrease of TSH plasma levels stimulated by Met-E. Our results suggest that Met-E plays a role in the release of TSH, and that dopamine is implicated in this process. The possible mechanisms through which Met-E influences TSH secretion are discussed.

Effects of morphine on the pituitary-thyroid axis: morphological and analytical studies.

The morphology of the TSH-producing pituitary cells and the thyroid gland, and plasma TSH, T3 and T4 hormone levels, were studied in normal rats, in rats treated with 10 micrograms morphine (M) and in M-treated animals pretreated with naloxone (Nx) (10 mg/kg). Morphological changes in the pituitary TSH cells and thyroid cells of M-treated animals were minimal and were not modified by Nx pretreatment. Plasma TSH levels in M-treated animals showed a significant decrease (P less than 0.05), which was not blocked by Nx pretreatment. No significant changes in plasma T3 or T4 levels were found in either experimental group.

Presence of catecholamine-related enzymes in a subpopulation of primary sensory neurons in dorsal root ganglia of the rat.

The presence of enzymes (tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (D beta H)) and enzymatic activities (monoamino oxidase, (MAO)) related to catecholamine synthesis and degradation have been investigated in cervical, thoracic and lumbar dorsal root ganglia (DRG) of adult male rats using immunohistochemical and enzyme histochemical techniques, respectively. A small population (between 2-4%) of TH-like immunoreactive and MAO positive neurons was found. They were small in diameter (18 +/- 2 microns), predominate in lumbar DRG and did not display D beta H-like immunoreactivity. These sensory neurons which are likely catecholaminergic were insensitive to systemic administration of capsaicin and 6-hydroxydopamine. Colchicine administration caused an increase of TH-like immunoreactivity and MAO activity. Pargyline produced an increase in TH-like immunoreactivity and the disappearance of MAO activity. The possible dopaminergic nature of the subpopulation of DRG sensory neurons investigated in the present study is discussed.

Localization of met-enkephalin like immunoreactivity in the glabrous skin of the cat rhinarium.

The presence of met-enkephalin like immunoreactivity (MEL IR) was investigated immunohisto-chemically in the glabrous skin of the cat rhinarium using the peroxidase-antiperoxidase Sternberger's method. Neither sensory corpuscles nor nerve bundles show MEL IR. MEL IR was found in the epidermal Merkel cells, as well as in Langerhans cells and/or melanocytes. In dermal papillae the reaction results positive in a number of cells which could be identified as Schwann or pigmentary cells.

Immunohistochemical study of cat Pacinian corpuscles: co-localization of vimentin- and S-100 protein-like in the inner core.

The presence of vimentin and S-100 protein in cat Pacinian corpuscles of cat mesentery has been investigated immunohistochemically (streptavidin-biotin method) using monoclonal antibodies. A positive reaction for both vimentin- and S-100 protein-like was found only in the lamellae of the inner core. The presence of vimentin and the co-expression of vimentin/S-100 protein-like in sensory corpuscles is reported for the first time. The authors discuss the origin of the inner core and capsule of sensory corpuscles on the basis of their immunohistochemical characteristics.

Vasoactive intestinal polypeptide (VIP)-like immunoreactivity in intraprostatic neurons and major pelvic ganglia in the rat.

VIP-like immunoreactive neurons have been found within the prostate and major pelvic ganglia of the male rats; they are of two different sizes. Moreover many VIP-like nerve fibers were found around the perikarya. On the basis of present data it is suggested that VIP-like prostatic nerves arise from both pelvic ganglia and intraprostatic neurons.

Immunohistochemical study of the sensory formations in the glabrous skin of the rat.

The presence of some cytoskeletal proteins related to the intermediate filaments glial fibrillary acidic protein -GFAP and vimentin) and S-100 protein has been investigated in sensory formations of the glabrous skin of the rat. A positive reaction both for S-100 protein and vimentin was found in the inner core and related cells of glomerular and simple sensory corpuscles; in contrast, no positive reaction was shown for GFAP. The authors discuss these results on the basis of the glial origin of the inner core and related cells in sensory formations.

Effects of met-enkephalin on the adrenocorticotropic cells of the rat pituitary.

The effects of chronic administration of met-enkephalin (40 micrograms/d during 20 days) on ACTH producing cells of the rat adenohypophysis have been studied both in light (PAP-immunocytochemistry for ACTH) and electron microscope. In addition a morphometric analysis and a percent distribution of secretory granules were performed. The ACTH cells of treated animals showed ultrastructural signs of hyperactivity, and some of them vacuolization (small vacuoles or a large central vacuole). The secretory granules of the experimental animals are larger and more spherical than the ones in the untreated and the control animals. We discuss the possible mechanism of action whereby met-enkephalin influences ACTH cells.

Expression of glial fibrillary acidic protein-like and S-100 protein like immunoreactivities on cartilages of the rat vestibulum nasi. Post-natal development changes.

The cartilages of vestibulum nasi in rats of different ages (newborns, 1 week, 1 month and 12 months old) were studied immunohistochemically using monoclonal antibodies against glial fibrillary acidic protein (GFAP) and S-100 protein. The immunoreaction for both GFAP and S-100 protein results positive in a variable number of chondrocytes. The number of chondrocytes displaying GFAP-like immunoreaction does not change during development and maturation, whereas those showing S-100 protein-like immunoreactivity increase from birth to the adult state. The formation of cartilaginous tissue from neuroectodermic cells of neural crest has been postulated by several authors and our results strongly support these opinions; moreover, according to present findings S-100 protein could be involved in chondroid tissue formation.

[Microscopic innervation of the spermatic ducts and testis. I. Vas deferens]. / Inervación microscópica de las vías espermáticas y testículo. I. Vas deferens.

The microscopic innervation of the vas deferens in the rat was studied both in light and electron microscope. The nerve fibres form perivascular, intramuscular and subepithelial plexuses. Inside the connective tissue surrounding the vas deferens both isolated nerve fibres and sensory corpuscles (glomerular and Ruffine-like types) were observed. The varicosities and endings of nerve fibres contain synaptic vesicles of different sizes and electron characteristics. These varicosities were closely related to the smooth muscle cells and some of them lacked of Schwannian sheath. The nervous fibres were not in direct contact with the epithelial cells.

[An experimental pain model: the formaldehyde test]. / Un modelo de dolor experimental: el "test" del formaldehído.

Some papers have been published in relation to alternative models of experimental pain in animals. In this work, with the aim of proving the validity, safety, reproducibility and objectivity of this model, we have compared the behaviour of the animal under the formaldehyde test before and after the intracerebroventricular administration of morphine, proving itself as an ideal model for the study of chronic pain caused by an excess of nociception.