Clinical Application of Angulated Prosthetic Platform Implants: A Retrospective Study

This retrospective study reports on the survival of two-piece angulated prosthetic platform (APP) implants consecutively placed at a specialist periodontics clinic with a mean follow-up of 28.2 ± 15.6 months (range 4.0-71.0). For 183 recalled patients that received 239 implants, modelled survival at follow-up up to 71 months was 99.2% and 91.1% at the patient and implant level respectively. The majority of patients were non-smokers and non-diabetics, with a quarter having a history of treated periodontitis. Eighty percent of patients received a single APP implant. Sixty-three percent of implants supported a single crown, 28% a fixed partial denture, and 9% a fixed complete denture. Nearly all implants were placed either at the time of tooth extraction or after complete bone healing, in approximately equal numbers. Three quarters had adjunct bone grafting with a quarter having adjunct soft tissue grafting. For 210 surviving and restored implants with satisfactory intra-oral radiographs taken at last recall with a mean follow-up 28.4 ± 15.5 months (range 4.0-71.0), the mean radiographic bone levels were -0.70 ± 0.87 mm (range -3.60 - +2.15). The results demonstrated clinically successful use of this unique geometry implant for multiple applications with acceptable short to medium term clinical outcomes.

An evaluation of gingival phenotype and thickness as determined by indirect and direct methods

OBJECTIVES

To evaluate gingival phenotype (GP) and thickness (GT) using visual, probing, and ultrasound (US) methods and to assess the accuracy and consistency of clinicians to visually identify GP.

MATERIALS AND METHODS

The GP and GT of maxillary and mandibular anterior teeth in 29 orthodontic patients (mean age 25 ± 7.5 years) were assessed using probing and US by a single examiner. General dentist and dental specialist assessors (n = 104) were shown intraoral photographs of the patients, including six repeated images, and asked to identify the GP via a questionnaire.

RESULTS

An increasing trend in GT values of thin, medium, and thick biotype probe categories was found, though this was not statistically significant (P = .188). Comparison of probing method to determinations of GT made by US yielded slight agreement (κ = 0.12). Using the visual method, assessors' identification of the second GP determination ranged from poor to moderate agreement (κ = 0.29 to κ = 0.53).

CONCLUSIONS

The probe method is sufficient in differentiating between different categories of GP. However, further research is required to assess the sensitivity of the probe method in recognizing phenotypes in the most marginal of cases. Assessors using the visual method lack the ability to identify GP accurately and consistently among themselves.

Effect of craniofacial morphology on gingival parameters of mandibular incisors

OBJECTIVES

To investigate the association between the width of keratinized gingiva (WKG), gingival phenotype (GP), and gingival thickness (GT) with craniofacial morphology in sagittal and vertical dimensions.

MATERIALS AND METHODS

WKG, GP, and GT of mandibular anterior teeth in 177 preorthodontic patients (mean age 18.38 ± 5.16 years) were assessed clinically using a periodontal probe, a Colorvue Biotype Probe, and ultrasound by a single examiner. Patients were grouped into skeletal Class I, II, and III and hyperdivergent, normodivergent, and hypodivergent based on ANB and SN-MP angles. Mandibular incisor inclination (L1-NB) was also measured. Clinical and cephalometric measurements were repeated to assess inter- and intraexaminer reproducibility.

RESULTS

A significant association was found between thin GP and skeletal Classes I and III for the left mandibular central incisor (MCI; P = .0183). In skeletal Class III patients, L1-NB angle demonstrated a decreasing trend as phenotype thickness decreased. A significant association was found between thin phenotype and normodivergent and hypodivergent groups for MCIs (left: P = .0009, right: P = .00253). No significant association between WKG or GT and craniofacial morphology was found.

CONCLUSIONS

Thin GP is associated with skeletal Class I and III for the left MCI. Thin GP is associated with hypodivergent and normodivergent skeletal patterns for the MCIs. There was no association between WKG and GT and craniofacial morphology in both skeletal and vertical dimensions. Dental compensations that exist due to different craniofacial morphology may influence the GP.

Increased Levels of C5a in Gingival Crevicular Fluid and Saliva of Patients with Periodontal Disease

C5a is a powerful complement effector molecule that is considered to be an important proinflammatory mediator in several systemic chronic inflammatory diseases. However, its levels in periodontal diseases are yet to be assessed. We aimed to analyse the secretion of C5a in gingival crevicular fluid (GCF) and saliva of patients with periodontal disease. Twenty-eight patients diagnosed with stage 3–4 periodontitis and 16 periodontally healthy subjects participated in this study. GCF was collected from sites with the deepest probing depth of each patient, and volume was measured using a Periotron 8000^®. One mL of unstimulated saliva was also collected. Samples were analysed using a commercially available ELISA kit. The data were analysed using the Mann–Whitney U test, Pearson’s bivariate testing, and receiver operating characteristic curve. C5a was present in GCF from patients with periodontitis (1.06 ± 0.25 ng/mL) whilst it was undetected in controls. Saliva concentration was also significantly higher in periodontitis (1.82 ± 2.31 ng/mL) than controls (0.60 ± 0.72 ng/mL, p = 0.006). C5a levels were more pronounced in periodontitis in both oral fluids assessed by the present pilot study. These results suggest that the more pronounced levels of C5a in oral fluids from periodontitis patients indicate a potential role of this molecule in this disease pathogenesis, deserving to be better explored in subsequent studies.

Success Rates and Complications Associated with Single Immediate Implants: A Systematic Review

This study examined the success rates of single immediate implants and their associated biological, hardware and aesthetic complications. Using a developed search strategy, randomized controlled trials (RCTs) on single-unit immediate implants with at least six human participants, a minimum follow-up time of 12 months and published between January 1999 and January 2021 were identified. Data was extracted independently using pre-designed data extraction forms. Information on success rates and associated biological, hardware and aesthetic complications were obtained and assessed. Out of 191 potentially eligible studies, 26 RCTs assessing 1270 patients with a total of 1326 single implants were included and further evaluated. In this review, success rate was reported to be 96.7–100% over a total of 9 studies. However, there was a lack of consensus on a universal success criterion between authors emphasizing the need for agreement. The average follow up was 29 months and most reported complications were aesthetic (63 cases, 4.7%), whilst there were relatively fewer biological, (20 cases, 1.5%), and hardware complications (24 cases, 1.8%). Success rate is an uncommon clinical outcome with 9 out of 26 of the selected RCTs reporting it. In these studies, single immediate implants showed a high success rate with low numbers of biological and hardware complications, and high patient satisfaction with aesthetics were reported in the short-term follow-up of one year.

Effect of photoperiod on ovarian maturation in Cheirodon interruptus (Teleostei: Characidae)

Cheirodon interruptus is a ubiquitous small characid that inhabits the Pampean region and commonly used as bait. Its vast market is supplied from the wild population causing a significant environmental impact. In this study, we assess the effect of photoperiod on ovarian maturation in order to evaluate its potential as a tool to manipulate reproduction under artificial conditions. Four treatments in triplicate (light: dark, L: D) were tested: 24L: 0D, 12L: 12D, 0L: 24D and a progressive photoperiod corresponding to the daily photoperiod increments in wild during winter-spring transition, accelerated three times. The experiment was conducted for 45 days. Gonadosomatic index (GSI), oocyte mean diameter, vitellogenic oocyte proportions, plasma estradiol concentrations (E2), condition factor (Kn) and standard length were estimated. Values of mean GSI, oocyte diameter, vitellogenic oocyte proportions and E2 concentration were maximum in the progressive treatment indicating vitellogenesis stimulation. In turn the same parameters were minimum in the 24L: 0D, revealing the vitellogenesis inhibition. This study showed that photoperiodic regime play an important role in the onset of ovarian maturation in C. interruptus.

Pituitary-thyroid axis development during the larval-juvenile transition in the pejerrey Odontesthes bonariensis

The morphological development of the thyroid gland of pejerrey Odontesthes bonariensis during larval-juvenile transition was studied and related to whole-body concentrations of thyroxine (T₄ ) and tri-iodothyronine (T₃ ). A complementary (c)DNA fragment of the thyroid-stimulating hormone β-subunit (tshb) was sequenced and transcript levels quantified during this period. Follicles with eosinophilic and T₄ -immunoreactive colloids were detected at hatching together with tshb transcript levels and whole-body concentrations of T₄ and T₃ hormones. Thyroid follicles were located in the subpharyngeal region associated with the ventral aorta below the hyoid bone. Follicle structure switched from the rounded form at hatching to oval in juveniles. Significant increase of follicle number per larva, mean colloidal area and total colloidal area was observed throughout development with maximum values at the end of the larval-juvenile transition. A significant decrease of tshb expression together with a significant increase in T₄ and T₃ whole-body concentrations was observed prior to achieving the juvenile phenotype. These results are in accordance with a negative feedback regulation of tshb expression by thyroid hormones and a possible association between thyroid hormone levels and the acceleration of metabolic processes necessary to complete metamorphosis.

Herbivore-induced plant volatiles can serve as host location cues for a generalist and a specialist egg parasitoid

Herbivore-induced plant volatiles are important host finding cues for larval parasitoids, and similarly, insect oviposition might elicit the release of plant volatiles functioning as host finding cues for egg parasitoids. We hypothesized that egg parasitoids also might utilize HIPVs of emerging larvae to locate plants with host eggs. We, therefore, assessed the olfactory response of two egg parasitoids, a generalist, Trichogramma pretiosum (Tricogrammatidae), and a specialist, Telenomus remus (Scelionidae) to HIPVs. We used a Y-tube olfactometer to tests the wasps' responses to volatiles released by young maize plants that were treated with regurgitant from caterpillars of the moth Spodoptera frugiperda (Noctuidae) or were directly attacked by the caterpillars. The results show that the generalist egg parasitoid Tr. pretiosum is innately attracted by volatiles from freshly-damaged plants 0-1 and 2-3 h after regurgitant treatment. During this interval, the volatile blend consisted of green leaf volatiles (GLVs) and a blend of aromatic compounds, mono- and homoterpenes, respectively. Behavioral assays with synthetic GLVs confirmed their attractiveness to Tr. pretiosum. The generalist learned the more complex volatile blends released 6-7 h after induction, which consisted mainly of sesquiterpenes. The specialist T. remus on the other hand was attracted only to volatiles emitted from fresh and old damage after associating these volatiles with oviposition. Taken together, these results strengthen the emerging pattern that egg and larval parasitoids behave in a similar way in that generalists can respond innately to HIPVs, while specialists seems to rely more on associative learning.

Implications of climate change for the reproductive capacity and survival of New World silversides (family Atherinopsidae)

The New World silversides (family Atherinopsidae) are found in marine, estuarine and inland waters of North, Central and South America, where they are ecologically important as forage fishes and sometimes economically important for commercial and recreational fisheries. This report reviews the knowledge of the reproductive attributes of temperate and subtropical atherinopsids in relation to temperature and discusses the potential effects of climate change on their reproduction and adaptive responses. Their reproductive cycles are primarily entrained by photoperiod with high temperature acting as a limiting factor. They are generally multiple spawners which release successive batches of eggs in spring, but some species can spawn also in autumn and even summer when temperatures do not increase excessively. The decoupling of temperature patterns and photoperiod with further global warming and associated asymmetric thermal fluctuations could lead to spawning at times or temperatures that are unsuitable for larval development and growth. Many members of this family show temperature-dependent sex determination (TSD), where the phenotypic sex of an individual is determined partly or wholly by the temperature experienced during gonadal sex differentiation, and high-temperature induced germ cell degeneration and decreased fertility. The predicted short-term reproductive responses of atherinopsids to climate change therefore include acceleration, shortening or overall disruption of spawning activity, and also more subtle, but nonetheless equally population-threatening, dysfunctions such as highly skewed sex ratios and partial or total loss of fertility. In the case of species with TSD, asymmetric thermal fluctuations could also cause larvae to encounter temperatures lower than normal during early development and be feminized. Such dysfunctions have been documented already in natural populations but are confined so far to landlocked, inland water habitats, perhaps because they impose more severe thermal fluctuations and limitations to migration and dispersal. The severity and recurrence of these dysfunctions with further climate change will depend both on the magnitude, speed and pattern of change and on how much (or how fast) physiological and behavioural traits can evolve to match the new conditions imposed by the climate, which is largely unknown. In this regard, compelling evidence is shown that numerous traits, including the sex determination system, are capable of rapid evolution and could mitigate the negative effects of temperature increases on population viability in atherinopsids.

Effects of light and temperature conditions on the expression of GnRH and GtH genes and levels of plasma steroids in Odontesthes bonariensis females

In this study we examined the endocrine mediation between environmental factors (temperature and photoperiod) and the brain-pituitary-gonadal axis in females of pejerrey Odontesthes bonariensis. Changes in the expression of brain gonadotropin-releasing hormones (GnRHs) and gonadotropin (GtH) subunit [follicle stimulating-beta (FSH-beta), luteinizing hormone-beta (LH-beta), glycoprotein hormone-alpha (GPH-alpha)] genes, plasma gonadal steroids [estradiol (E(2)) and testosterone (T)], gonadal histology, and gonadosomatic index (GSI) in adult females exposed to combinations of short-day (8 h) or long-day (16 h) photoperiods and low (12 degrees C) or high (20 degrees C) temperatures after winter conditions (8 h light, 12 degrees C) were analyzed. Pejerrey females kept under the short photoperiod had low GSIs, and their ovaries contained only previtellogenic oocytes regardless of the experimental temperature. In contrast, females exposed to the long photoperiod had high GSIs and ovaries with vitellogenic oocytes at both temperatures. These fish also showed a significantly higher expression of sGnRH, pjGnRH, cGnRH-II (the three different GnRH variants found to date in the pejerrey brain), FSH-beta, LH-beta and GPH-alpha genes and plasma E(2 )levels than those at the shorter photoperiod. No significant changes were observed in plasma T levels. Based on these results, we concluded that the increase in day length but not that of temperature triggers the maturation of pejerrey females after the winter period of gonadal rest and that this occurs by an integrated stimulation of the various components of the brain-pituitary-gonad axis.

The short-term effectiveness of non-surgical treatment in reducing protease activity in gingival crevicular fluid from chronic periodontitis patients

OBJECTIVES

The aim of this study was to evaluate the short-term effect of non-surgical periodontal treatment on protease activity in gingival crevicular fluid (GCF) of patients with chronic periodontitis.

MATERIAL AND METHODS

After clinical examination, in which pocket probing depth, probing attachment level, plaque and bleeding indices were recorded, gingival fluid samples from 21 chronic periodontitis patients were collected from gingivitis (GP) and periodontitis (PP) sites with an intracrevicular washing method. Samples were taken in the same way from a group of patients with gingivitis alone (GG). The periodontitis patients received non-surgical periodontal treatment and were re-evaluated 30 days later. We compared elastase and collagenase activities before and after treatment. The former activity was measured with a low-weight substrate (S-2484) and inhibited by alpha-1-antitrypsin. Matrix-metalloproteinase-8 (MMP-8) was measured with an ELISA and collagenolytic activity with fluorescein-conjugated collagen type I as substrate.

RESULTS

All clinical parameters showed a significant improvement after treatment (p<0.05) which was accompanied by a significant reduction in the values of total elastase activity, free elastase, MPP-8 and collagenolytic activity in both GP and PP sites (p<0.05). However, the latter sites continued to have higher levels of MMP-8 and collagenolytic activity than the former ones after treatment. The free elastase activity and the proportion of free elastase in GP and PP samples after treatment remained higher than in untreated GG samples.

CONCLUSION

This study shows that the clinical improvements after non-surgical treatment are accompanied by reductions in protease and neutrophil activities.

Expression of pejerrey gonadotropin-releasing hormone in three orders of fish

Molecular variants of GnRH were characterized by reverse-phase, high-performance liquid chromatography from brain extracts of fish in three different orders: Synbranchiformes (swamp eel [Synbranchus marmoratus]), Cyprinidontiformes (platyfish [Xiphophorus maculatus] and green swordtail [X. helleri]), and Atheriniformes (Patagonia pejerrey [Odontesthes hatchery]). Also, pituitary gland extracts from the pejerrey O. bonariensis (Atheriniformes) were characterized. Eluted fractions were tested in radioimmunoassays with antisera specific to GnRH, including both antisera that detected only one form of GnRH and those that detected several forms. The results show that brain extracts obtained from all species contained the same three molecular forms of GnRH, which were immunologically and chromatographically undistinguishable from chicken GnRH-II, pejerrey GnRH (pjGnRH), and salmon GnRH. This study supports the hypothesis that expression of these three forms is common in different fish orders and that pjGnRH is the main regulator of pituitary function in these fish.

Immunocytochemical identification of GtH1 and GtH2 cells during the temperature-sensitive period for sex determination in pejerrey, Odontesthes bonariensis

The ontogeny of gonadotropin 1 (GtH1) and 2 (GtH2) cells and its possible link to gonadal sex differentiation were studied in pejerrey, Odontesthes bonariensis, by immunocytochemistry using anti-chum salmon beta-GtH1 and beta-GtH2 antisera. In adults, GtH1 cells were found in the proximalis pars distalls (PPD) close to the neurohypophysis, whereas GtH2 cells were identified surrounding GtH1 cells, at the external layer of the PPD and in the pars intermedia. Essentially the same distribution was observed in larvae. In pejerrey, the phenotypic sex is governed by the temperature during the critical period of sex determination (temperature-dependent sex determination, TSD). Female proportions vary gradually from 100% at 15-19 degrees to 0% at 29 degrees, and the critical time of TSD has been estimated to be 3-5, 2-4, and 1-4 weeks after hatching at 17, 19, and 27 degrees, respectively. Thus, the expression of both GtHs was examined weekly in larvae reared from hatching to week 11, at 17, 24, and 29 degrees. The proportion of females at 17, 24, and 29 degrees was, 100%, 78%, and 0%, respectively. Histological ovarian differentiation was noticed at 7 and 4 weeks at 17 and 24 degrees, whereas testicular differentiation occurred at 7 and 4 weeks at 24 and 29 degrees. GtH1 cells were first observed at week 3 at 29 degrees and at week 4 at 17 and 24 degrees. These cells increased in number until week 4 and then decreased, disappearing after week 6 at all temperature regimes. GtH2 cells appeared at week 2 at 24 and 29 degrees and at week 3 at 17 degrees. GtH2 cell number increased until week 3 at 29 degrees and until week 4 at 17 and 24 degrees and then temporarily decreased, thereafter increasing again. These results strongly suggest that GtH1 and GtH2 are expressed by different cells. The fact that GtH1 and GtH2 cells appear just before histological gonadal differentiation at all temperatures, together with the peak of GtH1 and GtH2 cell number during the temperature-sensitive period, suggests that GtHs are related to sex differentiation or TSD in O. bonariensis.

Fluoride release and uptake from glass ionomer cements and composite resins

The aim of this investigation was to evaluate fluoride release and uptake from 4 glass ionomer cements (GICs)--Vitremer (VIT), Fuji II LC (FII LC), Fuji IX (FIX), Chelon Fill (CHE)--and 2 composite resins (CRs)--Heliomolar (H) and Zeta-100 (Z-100). Eight discs (8 mm x 2 mm) were made of each material and were stored in plastic vials containing artificial saliva at 37 degrees C. In group 1 (N = 3), the specimens were immersed in artificial saliva which was changed daily for 25 days. In group 2 (N = 5), besides receiving the same treatment as group 1, the specimens were immersed, after 24 hours, in a fluoride solution (1% NaF) for 1 min before daily saliva change. An ion-specific electrode (9609 BN-Orion) connected to an ion analyzer (SA-720 Procyon) was used to determine the amount of fluoride released at days 1, 2, 5, 10, 15, 20 and 25. Data were analyzed using two way ANOVA and Friedman's test. GICs released more fluoride during the first day and after this period the mean fluoride released decreased. Composite resin H released fluoride during the first day only and Z-100 did not release fluoride. In terms of NaF treatment, CRs did not show fluoride uptake, whereas the GICs showed fluoride uptake (VIT = FII LC = CHE > FIX).

Corticotropin-releasing factor accelerates metamorphosis in Bufo arenarum: effect on pituitary ACTH and TSH cells

The actions of several neuropeptides as hypothalamic mediators in the regulation of Bufo arenarum metamorphosis were investigated. Prometamorphic larvae were injected with 1.5 microg thyrotropin-releasing hormone (TRH), 2 microg ovine corticotropin-releasing factor (oCRF), 2 microg mammalian gonadotropin-releasing hormone (mGnRH), 2 microg human growth hormone-releasing hormone (hGHRH), or Holtfreter solution (control group). Larvae received two injections with the same dose: one at the beginning of the experiment and the other 7 days later. Several morphologic parameters (total length, tail length, wet weight, hind limb length, and metamorphic stages) were measured as indicators of growth and metamorphic development. These measurements were taken in 20 larvae per treatment or control group at the beginning of the experiment, at day 7 and at day 14 when the experiment ended. We observed that only the administration of exogenous CRF stimulated resorption of the tail and accelerated the rate of metamorphosis. In the pituitary of CRF-treated larvae we observed that thyrotropin (TSH) and adrenocorticotropic hormone (ACTH) producing cells showed a weaker immunoreactivity, a decrease in cell number and a reduction of volume density when compared with normal larvae. In conclusion, the results obtained indicate a possible role for CRF in Bufo arenarum metamorphosis. CRF may regulate interrenal and thyroid activity by acting directly upon TSH and ACTH cells. On the other hand, TRH, GnRH and GHRH were inactive in stimulating growth or metamorphosis of Bufo arenarum. J. Exp. Zool. 286:473-480, 2000.

Immunoidentification of CRF-like material in the intermaxillary glands during Bufo arenarum development

The presence of corticotropin-releasing factor-like material in the intermaxillary glands was studied by immunocytochemical techniques during the metamorphosis of Bufo arenarum. The intermaxillary glands appeared at stage XV (midprometamorphosis) with CRF-like material slightly immunoreactive. These glands are located posterior to the premaxillae and between the nasal capsules in the roof of the mouth and are formed of alveoli or tubules. During metamorphic climax, corticotropin-releasing factor-like material was identified strongly immunostained at the apices of the secretory cells. It was observed that collecting ducts of the gland open to the anterior palatal surface suggesting that the secretion could be ingested by tadpoles. Our results clearly showed that ir-CRF-like material present in the intermaxillary glands is ingested by tadpoles during metamorphosis and could play an important role during amphibian development.

Thyrotropin-releasing hormone immunoreactivity in the brain and the pituitary during Bufo arenarum development

The ontogeny of the thyrotropin releasing hormone (TRH) neuronal system was evaluated by immunocytochemistry in Bufo arenarum. The first appearance of TRH immunoreactive fibers was at early premetamorphosis. These fibers were found in small numbers and weakly stained in the median eminence and pars nervosa. With the advance of larval development, TRH-like material stained intensely and tended to aggregate in the median eminence, pars nervosa and pars intermedia. At climax stages immunoreactive fibers and perikarya (weakly stained) were also identified in the preoptic area. In adult specimens TRH perikarya and neuronal fibers were found in the preoptic and infundibular nuclei of the hypothalamus and in the amygdala, septum and diagonal band of Broca of the telencephalon. In addition, TRH neuronal fibers and endings were found in the preoptic-hypophyseal tract, the external zone of the median eminence, the pars nervosa and pars intermedia. Fibers were absent in the pars distalis. This study represents the first immunocytochemical demonstration of TRH in Bufo species, and serves as a basis for clarification of the neuroendocrine regulation of metamorphosis.

Identification and neuroanatomical distribution of immunoreactivity for mammalian gonadotropin-releasing hormone (mGnRH) in the brain and neural hypophyseal lobe of the toad Bufo arenarum

The presence and distribution of gonadotropin-releasing hormone (GnRH) in sexually mature specimens of Bufo arenarum was studied by reverse phase/high performance liquid chromatography (RP-HPLC) combined with radioimmunoassay and immunocytochemistry. The analysis of brain extracts with RP-HPLC followed by radioimmunoassay with PBL#45 antiserum showed the presence of only one peak with immunoreactivity for GnRH (ir-GnRH) having the chromatographic and immunological characteristics of mammalian GnRH (mGnRH). This peak was further analyzed with two mGnRH-specific antisera, EL-15 and m1076, yielding serial dilution displacement curves parallel to those obtained with the mGnRH synthetic standard. Immunocytochemical results with the monoclonal antibody LRH13 showed the presence of a terminal nerve-septo-preoptic system with neurons and fibers distributed from the olfactory bulb, septal area, and anterior preoptic area toward the hypothalamus and hypophyseal neural lobe. The main group of ir-GnRH fibers and neurons was identified in the anterior preoptic area. These neurons appear to be the origin of fibers that, after surrounding the preoptic recess, border the dorsal surface of the optic chiasma, extend through the infundibulum, traverse the external layer of the median eminence, and end in the pars nervosa.

Manometric measurement of anal canal resting tone: comparison of a rectosphincteric balloon probe with a water-perfused catheter assembly

The purpose of this study was to compare the manometric measurements of a rectosphincteric balloon probe with a water-perfused catheter assembly on anal canal resting tone. Ten normal subjects (9 males, 1 female; mean age: 32 years; range 27-46 years) underwent station pull-through (0.5 cm/3 sec) beginning in the rectum with a water-perfused catheter assembly and a rectosphincteric balloon probe. Both the probe and the catheter were 5 mm in diameter. Three catheter side ports were perfused at 1 ml/min, and the rectal balloon was inflated with 5 ml of air. Measurements were taken on the same day in a counterbalanced manner. Data were analyzed on a computerized system. Mean (+/-SEM) values with the balloon were 82.3 (+/-8.9) mm Hg and 97.1 (+/-9.3) mm Hg with the catheter. These values were not significantly different (P=0.22). A significant order effect (P=0.04) was found where the first measure (101.3+/-10.2 mm Hg) was higher than the second measure (78.1+/-6.6 mm Hg), which was controlled for in the experimental design. A rectosphincteric balloon probe can accurately measure the resting tone of the anal canal compared to a water-perfused catheter assembly. Caution should be used when measuring anal canal resting tone early in an anorectal manometry assessment.

Immunocytochemical distribution of corticotropin-releasing factor in the brain and hypophysis of larval Bufo arenarum; effect of KClO4 during early development

The maturation of the corticotropin-releasing factor (CRF) neuronal system was evaluated by immunocytochemistry and morphometry in Bufo arenarum, during spontaneous metamorphosis and in tadpoles with inhibited thyroid function. The first appearance of CRF immunoreactive fibers was at the end of premetamorphosis (stage VIII). These fibers were found in small numbers and weakly stained in the median eminence and infundibular stalk. With the advance of larval development, CRF-like material stained intensely and tended to aggregate in the external zone of the median eminence. At climax stages, immunoreactive fibers and perikarya (weakly stained) were identified in the interpeduncular nucleus and in the dorsal infundibular nucleus. Morphometric and immunocytochemical results indicate that the maturation of the CRF neuronal system in Bufo arenarum occurs just before metamorphic climax, coinciding with high levels of thyroid and steroid hormones. We have also found that in larvae with inhibited thyroid function, the CRF neuronal system is able to develop, and that thyroid hormone could exert a negative feedback control on the synthesis of CRF.

Ultrastructural study on thyroid glands of Bufo arenarum larvae kept in potassium perchlorate solution

The ultrastructure of thyroid glands in Bufo arenarum tadpoles was studied with inhibited thyroid function. After hatching, larvae were kept in potassium perchlorate solution, a goitrogenic substance known to prevent absorption of iodine from water or food, resulting in impaired thyroid hormone synthesis. Increased thyroid gland volume and follicular cell height were observed in treated larvae. The changes in size and volume of follicular cells in experimental tadpoles appeared to be mainly a function of the overstimulation of proteinpoietic apparatus. The cell shows a conspicuous development of endoplasmic reticulum and Golgi complex, as well as an increase in number of mitochondria and colloid droplets. These observations in follicular thyroid cells from Bufo arenarum, obtained under such experimental conditions, were interpreted in terms of interruption of negative feedback mechanisms involving the decrease in the thyroxine circulatory level, and therefore the increase in hypothalamo-hypophyseal endocrine secretory stimulation.

Immunocytochemical and morphometric study on the changes of TSH, PRL, GH and ACTH cells during the development of Bufo arenarum

The development and dynamics of thyrotropin (TSH), adrenocorticotropic hormone (ACTH), prolactin (PRL), and growth hormone (GH) cells have been studied using immunocytochemical techniques and rabbit antisera, raised against the relevant human hormone, in the pars distalis of Bufo arenarum larvae at different stages of development. The four types of cells studied were identified in different zones of the pars distalis: TSH cells occurred mainly in the centro-ventral zone, ACTH cells in the rostral and dorsal zones, GH cells in the central and caudal zones, and PRL cells in the anterior two-thirds of the gland. This distribution pattern does not show significant changes with development. Morphometry and stereology were used to evaluate the changes observed in the volume of the pars distalis and the immunoreactive cells during development. The former increased during larval growth and decreased throughout the metamorphic climax. The results obtained on cell number, volume density, and total volume suggest that, during larval growth (pre-prometamorphosis) of B. arenarum, TSH, PRL, GH and ACTH cells show a proliferative period with storage of their hormones; a second period involving hormone release occurs at the metamorphic climax.

Immunocytochemical and morphometric study of TSH, PRL, GH, and ACTH cells in Bufo arenarum larvae with inhibited thyroid function

Changes in the pituitary cells involved in amphibian metamorphosis were studied in Bufo arenarum tadpoles with inhibited thyroid function. After hatching, larvae were treated for 5 months with potassium perchlorate (KClO4), a goitrogenic substance known to prevent absorption of iodine from water or food, resulting in impaired thyroid hormone synthesis. Treated larvae continued to grow but halted their development in premetamorphosis, showing hyperplastic thyroid glands with disorganized follicles lacking colloid. Thyrotrop (TSH), lactotrop (PRL), somatotrop (GH), and corticotrop (ACTH) cells were stained immunocytochemically and the changes observed were evaluated morphometrically using an automatic image analyzer. Pars distalis volume increased in treated larvae. Morphometric results showed that, in treated tadpoles, TSH and PRL cell populations and cell volumes increased compared to normal larvae at the same stage. Changes in the GH and ACTH cell morphometry were slight. These results indicate that in Bufo tadpoles, after chronic thyroid hormone withdrawal, TSH, PRL, GH, and ACTH cells are able to develop and that thyroid hormones exert a strong feedback control on the synthesis and storage of TSH and PRL.