Posterior Tube Research Articles

Facilitating tracheal intubation in pediatric patients with the Airtraq® optical laryngoscope

To the Editor, The Airtraq optical laryngoscope (Airtraq) (Prodol Meditec S.A., Vizcaya, Spain) is a relatively new disposable tracheal intubation device with an anatomically shaped blade that has two parallel channels, the optical channel and the guiding channel, which accommodates the endotracheal tube (ETT). The Airtraq incorporates a guiding channel to the right of the viewing axis to solve the challenge of passing the ETT through the glottis. However, delivering the ETT through the gap between the end of the guiding channel tube to the glottis may not be straightforward. The guiding channel tube and viewing axis are somewhat incongruent, because the direction of ETT advancement from the guiding channel is defined by the configuration of the guiding channel tube and the ETT angulation. When attempting to advance the ETT through the laryngeal aperture with the Airtraq during tracheal intubation, it has been reported that a posterior tube tip location can be problematic, especially for pediatric patients. On the basis of our cumulated experience with the Airtraq, which includes more than 500 pediatric patients to date, another possible difficulty in advancing the ETT through the glottis, especially in infants and young children with smaller airways, is a left tube tip location. This potential problem arises because the Airtraq is designed with the guiding channel at the right of the viewing axis, and a left-oriented slope at the right side of the distal opening of the guiding channel is devised to direct the tube tip into the glottis in the midline (Figure, Panel A). This design results in ETT advancement from the guiding channel towards the left. Consequently, during advancement of the ETT, the tube tip may move across the midline (Figure, Panel B) towards either the left vocal cord or the left laryngeal vestibule rather than align the ETT towards the midline of the glottis (Figure, Panel C). Whenever this problem arises, our practice has been to withdraw the ETT by approximately 0.5 cm and to exercise one of four available options: 1) slightly rotate the Airtraq in a clockwise direction; 2) advance the Airtraq downwards; 3) gently apply leftwards laryngeal pressure with external laryngeal manipulation, then re-attempt ETT advancement; and 4) in the very rare occasions the above measures fail, withdraw the ETT from the guiding channel and introduce a pediatric bougie into the visualized glottis via the guiding channel. The ETT is then railroaded along the bougie through the larynx, and the Airtraq is used to monitor the progress of the ETT advancement. Over the previous two years, we have used these maneuvers quite successfully to facilitate advancing the ETT into the glottis with the Airtraq device in pediatric patients with uncomplicated and difficult airways alike.

Posterior migration of Ahmed glaucoma valve tube in a patient with Reiger anomaly: a case report

BackgroundTo describe, a yet non-documented complication of GDI surgery (glaucoma drainage incision surgery) - anterior to posterior segment migration of Ahmed Glaucoma Valve (AGV) tube.Case PresentationWe report a young 9 year old boy, diagnosed with refractory glaucoma with Reiger anomaly. History included of poor vision in both eyes, left more than right with glare since childhood. He underwent GDI surgery with AGV implantation following which he developed posterior migration of AGV tube. The detailed ocular history, ophthalmic findings, clinical course, surgical management and development of the posterior tube migration is discussed.ConclusionPosterior Migration of AGV tube has yet not been described. Also there is a role of expectant management of the complication in this case as evidenced by the benign course of events.

Combined 25-Gauge Vitrectomy and Posterior Tube Shunt Placement for Advanced Glaucoma

To report the initial clinical outcomes of a combined procedure utilizing 25-gauge vitrectomy and posterior tube shunt placement in eyes with refractory glaucoma not amenable to standard treatment. Retrospective chart review. We included 10 eyes (10 consecutive adult patients, mean age 61 years) with advanced glaucoma and anterior segment abnormalities precluding tube placement in the anterior chamber who were treated with combined 25-gauge vitrectomy and posterior tube shunt placement. Records of consecutive patients were reviewed for demographics, etiology of glaucoma, preoperative clinical data (visual acuity, intraocular pressure, number of ocular antihypertensive medications), and postoperative outcome measures at predetermined time points. (1) Intraocular pressure (IOP) at 1, 2, 6, and 12 months postoperatively; (2) number of ocular antihypertensive medications needed at 12 months postoperatively; (3) visual acuity (VA) at 12 months postoperatively; and (4) incidence of hypotony, retinal detachment, endophthalmitis, and corneal decompensation. Preoperatively, mean IOP was 31 mmHg, and patients required a mean of 2.5 ocular antihypertensive medications. Mean IOP at 1, 2, 6, and 12 months postoperatively were 17.0, 16.1, 17.8, and 16.1 mmHg, respectively, and significantly lower than preoperative IOP (P < 0.005 at all time points). At 1 year postoperatively, 90% of patients had an IOP < 20 mmHg, and 50% of patients required ≤ 2 ocular antihypertensive medications. At 1 year postoperatively, VA was the same or improved in 70% of patients, and no worse than 1 Snellen line in any patient. Corneal edema developed in 2 patients. No patient developed hypotony or endophthalmitis. Combined 25-gauge vitrectomy and posterior tube shunt placement can be successful in lowering IOP in eyes with advanced glaucoma not amenable to other therapies.

Mineralization of vestimentiferan tubes at methane seeps on the Congo deep-sea fan

Vestimentiferan tube worms are prominent members of modern methane seep communities and are totally reliant as adults on symbiotic sulphide-oxidizing bacteria for their nutrition. The sulphide is produced in the sediment by a biochemical reaction called the anaerobic oxidation of methane (AOM). A well-studied species from the Gulf of Mexico shows that seep vestimentiferans ‘mine’ sulphide from the sediment using root-like, thin walled, permeable posterior tube extensions, which can also be used to pump sulphate and possibly hydrogen ions from the soft tissue back into the sediment to increase the local rate of AOM. The ‘root-balls’ of exhumed seep vestimentiferans are intimately associated with carbonate nodules, which are a result of AOM. We have studied vestimentiferan specimens and associated carbonates from seeps at the Kouilou pockmark field on the Congo deep-sea fan and find that some of the posterior ‘root’ tubes of living specimens are enclosed with carbonate indurated sediment and other, empty examples are partially or completely replaced by the carbonate mineral aragonite. This replacement occurs from the outside of the tube wall inwards and leaves fine-scale relict textures of the original organic tube wall. The process of mineralization is unknown, but is likely a result of post-mortem microbial decay of the tube wall proteins by microorganisms or the precipitation from locally high flux of AOM derived carbonate ions. The aragonite-replaced tubes from the Kouilou pockmarks show similar features to carbonate tubes in ancient seep deposits and make it more likely that many of these fossil tubes are those of vestimentiferans. These observations have implications for the supposed origination of this group, based on molecular divergence estimates.

Description of Pseudorhabdosynochus justinei n. sp. (Monogenea: Diplectanidae) and redescription of P. vagampullum (Young, 1969) Kritsky & Beverley-Burton, 1986 from the gills of the longfin grouper Epinephelus quoyanus (Valenciennes) (Perciformes: Serranidae) in Dapeng Bay, South China Sea.

Pseudorhabdosynochus justinei n. sp. is reported and described from the gills of the longfin grouper Epinephelus quoyanus in Dapeng Bay, South China Sea off the town of Nan'ao, Shenzhen, Guangdong Province, China. P. justinei n. sp. is characterised by the presence of a male copulatory organ (MCO) composed of a moderately quadriloculate organ, a short cone and a long, variable internal tube, and a sclerotised vagina comprising anterior 'trumpet' with a characteristic sclerotised ring, slightly medially curved canal, heavily sclerotised principal chamber and star-shaped lateral structure with accessory chambers. It is differentiated from the most similar species, P. caledonicus Justine, 2005, by the absence of a thinly sclerotised posterior tube of the MCO and by the size and morphology of the sclerotised vagina. P. vagampullum (Young, 1969) is redescribed based on specimens collected from the same species of host and locality as P. justinei n. sp. In comparison with the original description by Young [Young, P. C. (1969). Journal of Helminthology, 43, 223-254] and the redescription by Justine [Justine, J.-L. (2005a). Systematic Parasitology, 62, 1-37; (2005b). Systematic Parasitology, 62, 39-45] based on old museum material, the new specimens of P. vagampullum clearly showed the internal anatomy of the terminal genitalia, especially the sclerotised vagina, consisting of a distal, cylindrical canal with an anterior 'trumpet' continuing as an unsclerotised, curved, bulb-shaped vaginal pore, a conical principal chamber and a star-shaped lateral structure with an accessory chambers leading to the seminal receptacle via a fine, unsclerotised duct.

Pseudorhabdosynochus venus n. sp. (Monogenea: Diplectanidae) from Epinephelus howlandi (Perciformes: Serranidae) off New Caledonia.

Pseudorhabdosynochus venus n. sp. is described from specimens collected from the gills of Epinephelus howlandi off Nouméa, New Caledonia, South Pacific. The male sclerotised quadriloculate organ of P. venus, 61-101 microm in internal length, has an anterior chamber with a thin anterior wall, a very short cone and a short posterior tube. The sclerotised vagina, 50-67 microm in total length, is composed of an anterior open trumpet, an S-shaped canal, a tear-shaped principal chamber and a spherical accessory chamber; all parts are heavily sclerotised. The two squamodiscs have 10-11 rows of separate rodlets and no central closed row of rodlets. P. venus is differentiated from all other species of Pseudorhabdosynochus by the spectacular morphology of its sclerotised vagina. It is the first diplectanid described from E. howlandi.

Pseudorhabdosynochus hirundineus n. sp. (Monogenea: Diplectanidae) from Variola louti (Perciformes: Serranidae) off New Caledonia.

Pseudorhabdosynochus hirundineus n. sp. is described from specimens collected from the gills of Variola louti off Nouméa, New Caledonia, South Pacific. No diplectanid was found on V. albimarginata from the same location. The male sclerotised quadriloculate organ of P. hirundineus is 42 microm in internal length, with a long posterior tube; and the sclerotised vagina, 36 microm in length, is composed of a long tube with anterior open trumpet and two posterior, heavily sclerotised chambers. The two squamodiscs, each with 11-15 rows of rodlets and no central closed row of rodlets, are dissimilar in shape, the ventral being round and the dorsal being oval. By the morphology of its sclerotised vagina, P. hirundineus appears close to P. epinepheli (Yamaguti, 1938) but it is differentiated from it by the shape of its squamodiscs. Pseudorhabdosynochus spp. previously recorded from epinephelines are parasites of species of Epinephelus and Mycteroperca; this is the first species from a species of Variola.

Assessment of patient radiation doses during transcatheter closure of ventricular and atrial septal defects with Amplatzer devices

The purpose of this study was to estimate the radiation dose to which children are exposed during cardiac catheterizations for the treatment of ventricular and atrial septal defects. Radiation doses were estimated for 46 children aged 1-18 years. These children were treated for secundum atrial septal defects (ASD group) for perimembranous ventricular septal defects (VSD group) or underwent a routine diagnostic catheterization (diagnostic group). Thermoluminescent dosimeters (TLDs) were attached in locations, representing the lateral entrance dose, the posterior entrance dose, the thyroid dose, and the gonad dose, respectively. A dose area product (DAP) meter was also attached externally on the posterior-anterior (PA) tube to give a direct value in cGy cm(2) for each procedure. The patient's entrance dose from the PA field ranged from 1.5 to 185.0 mGy for all patients, while the lateral entrance dose varied from 0.9 to 204 mGy. Radiation exposure to the thyroid and the gonads was found to vary from 0.4 to 8.3 and 0.1 to 2.1 mGy, respectively. The DAP meter recorded DAP values for the posterior tube, between 46 and 3,700 cGy cm(2). The mean effective dose was found to be 7.7, 16.2, and 33.3 mSv for the diagnostic, the ASD, and the VSD group, respectively. Very strong correlation was found between the DAP values and the entrance radiation dose measured with TLDs. The mean entrance dose received from therapeutic cardiac catheterizations using the Amplatzer devices was found approximately twice the dose received from a diagnostic one. Even for the most complex procedures, the maximum entrance dose was at least 10 times lower than the threshold, associated with skin erythema.

Habitat, growth and physiological ecology of a basaltic community of Ridgeia piscesae from the Juan de Fuca Ridge

The vestimentiferan tubeworm Ridgeia piscesae is an ecosystem-structuring organism in the hydrothermal vent environments of the Northeast Pacific. During this study, a single representative aggregation of the long-skinny morphotype of R. piscesae from the main endeavor segment was monitored for 3 yr before being collected in its entirety with a hydraulically actuated collection device manipulated in situ by a research vehicle. Vestimentiferan growth rates in this aggregation were determined by staining the exterior of the tubes and measuring newly deposited tube sections. The average growth rate of R. piscesae in this aggregation was very low in both years of the growth study (3.2 mm yr −1). Although the incidence of plume damage from partial predation was very high (>95%), mortality was very low (<4% yr −1). The distribution and the very tight clustering of recently recruited individuals indicated gregarious settlement behavior that is hypothesized to be partly due to biotic cues from settled larvae. Coupled measurements of vent fluid sulfide concentration and temperature were used to calculate the exposure of the vestimentiferans to sulfide from short- and long-term temperature monitoring. Plume-level temperature records indicate that most of the time individuals in this aggregation were exposed to extremely low levels of vent fluid, and therefore sulfide (<0.1 μM), while their posterior sections were consistently exposed to sulfide concentrations in the 100 μM range. A rootball-like structure formed the common base of the aggregation. In contrast to the anterior sections of the tubeworm tubes, the portions of the tubes within the “rootball” were freely permeable to sulfide. The results of this study show that R. piscesae, unlike vestimentiferans from the East Pacific Rise, can survive and grow in areas of low diffuse vent flow with very low plume-level exposure to sulfide. We propose that this morphotype of R. piscesae has the ability to acquire sulfide from sources near their posterior ends, similar to some species of cold seep vestimentiferans from the Gulf of Mexico. The ability of this single species of vestimentiferan to survive low exposure to vent flow with low mortality coupled with sulfide uptake across posterior tube sections may help explain the occurrence of a single vent vestimentiferan species in a wide variety of habitat conditions at hydrothermal vent sites in the Northeast Pacific.

Complications of glaucoma drainage implant surgery.

Glaucoma drainage implants play an important role in the management of refractory glaucoma. It may be considered as a primary procedure in eyes with severe scarring of the conjunctiva and the limbus, neovascularization, multiple previous, failed filtering procedures, and severely glaucomatous eyes for which corneal graft is planned. Recommendations have been made regarding improving the biocompatibility of the materials used in the manufacture of these implants. The current state of development of glaucoma drainage implants is likened to that of intraocular lenses in the 1970s. Further development of devices and techniques will only serve to improve our armamentarium and success against glaucoma, specifically refractory glaucoma. Glaucoma posterior tube shunts have proved to be safe, with the majority of complications either nonsight-threatening, spontaneously resolving, or reversible. Considered primarily in the most severe cases of refractory glaucoma, it has otherwise changed the outlook for such patients.

Krupin Eye Valve with Disk for Filtration Surgery

The authors evaluate a long posterior tube shunt device with a pressure sensitive valve for filtration surgery in eyes with recalcitrant glaucoma.The device consisted of an anterior chamber tube connected to an oval (13 x 18 mm) episcleral explant. The explant was designed to maximize the area of surrounding encapsulation while still allowing implantation within one quadrant. A pressure-sensitive and unidirectional slit valve in the tube provided resistance to aqueous humor flow. One-stage implantation without the use of restrictive sutures was performed in 50 eyes with various types of glaucoma unresponsive to prior glaucoma surgery.Mean (+/- standard error of the mean) preoperative intraocular pressure (IOP) of 36.4 +/- 1.6 mmHg was reduced significantly (P < 0.001) to 8.3 +/- 1.3 mmHg on the first postoperative day. Mean anterior chamber depth (scale, 0-4+) was 3.4 +/- 0.1. Mean IOP 1 month after surgery was 14.1 +/- 1.3 mmHg. The implant was removed from four eyes due to IOP failure (1 eye), external erosion (2 eyes), or endophthalmitis (1 eye). A suprachoroidal hemorrhage occurred in one eye on the first postoperative day. Diplopia developed in one eye after surgery. Mean IOP at last follow-up examination (mean, 25.4 +/- 2.4 months; range, 16-36 months) was 13.1 +/- 1.3 mmHg. Intraocular pressure was 19 mmHg or lower in 80% of the eyes, 59% of which were without adjunctive antiglaucoma medications.Design features of the Krupin Eye Valve with Disk result in a large area of encapsulation in a single ocular quadrant which functions as an external reservoir for passage of aqueous humor. The valve portion facilitates maintenance of anterior chamber depth during the early postoperative interval. This new therapeutic device can be effective in the long-term control of IOP in glaucomatous eyes not responsive to prior filtration surgery with adjunctive antimetabolite therapy.

Acoustic rhinometry as method for evaluating paranasal sinuses--experimental studies

The potential application of acoustic rhinometry for evaluating paranasal sinuses was evaluated experimentally. In order to assess the influence of paranasal sinus volume in acoustic rhinometry, three model studies were performed. A tube made of acryle (20 cm in length, 2 cm in diameter) with a side hole was used for the first experiment. In the experiment measuring this tube with acoustic rhinometry, a difference between cases with a side hole (ex. 2 mm in diameter) and these without a side hole was observed. In the former, a more posterior tube position gave rise to an increase in the acoustic curve. In the second experiment, a syringe was was fixed to the side hole of the tube, so as that no leakage of sound wave would occur. A change in the volume of the syringe could be detected by acoustic rhinometry, even with changes as small as 1 ml. In the third experiment, the relationship between the size of the side hole and the volume of the syringe was evaluated. When the volume was less than 20 ml, the value was almost equal to the theoretical value even if the diameter of the side hole was as small as 4 mm. A larger size hole was required when the volume was increased. It was concluded that acoustic rhinometry is of possible value in assessing the paranasal sinuses, if the nasal cavity communicates with the paranasal sinuses via a large opening (e.g. in post-operative cases).

Posterior tube shunt implants for glaucoma surgery.

(1991). Posterior Tube Shunt Implants for Glaucoma Surgery. Seminars in Ophthalmology: Vol. 6, No. 2, pp. 87-94.

Histology and functional morphology of the female reproductive tract of the tortoise Gopherus polyphemus.

The oviducts of 25 tortoises (Gopherus polyphemus) were examined by using histology and scanning electron microscopy to determine oviductal functional morphology. Oviductal formation of albumen and eggshell was of particular interest. The oviduct is composed of 5 morphologically distinct regions; infundibulum, uterine tube, isthmus, uterus, and vagina. The epithelium consists of ciliated cells and microvillous secretory cells throughout the oviduct, whereas bleb secretory cells are unique to the infundibulum. The epithelium and endometrial glands of the uterine tube histologically resemble those of the avian magnum which produce egg albumen and may be functionally homologous. The isthmus is a short, nonglandular region of the oviduct and appears to contribute little to either albumen or eggshell formation. The uterus retains the eggs until oviposition and may form both the fibrous and calcareous eggshell. The endometrial glands are histologically similar to the endometrial glands of the isthmus of birds, which are known to secrete the fibers of the eggshell. These glands hypertrophy during vitellogenesis but become depleted during gravidity. The uterine epithelium may supply "plumping water" to the egg albumen as well as transport calcium ions for eggshell formation. The vagina is extremely muscular and serves as a sphincter to retain the eggs until oviposition. Sperm are found within the oviductal lumen and endometrial glands from the posterior tube to the anterior uterus throughout the reproductive cycle. This indicates sperm storage within the female tract, although the viability and reproductive significance of these sperm are unknown.

Fishes of the southern hemisphere genusNeophrynichthys(scorpaeniformes : cottoidei), with descriptions of two new species from New Zealand and Macquarie Island

Two new species of Neophrynichthys are described, N. angustus from New Zealand and N. magnicirrus from Macquarie Island. Both have a narrow and rigid interorbital with strongly sculptured roofing bones. N. angustus has dark brown spots on a light background and is larger, occurs at greater depths, and is wider ranging than its New Zealand compatriot N. latus (Hutton, 1875). N. magnicirrus has a large cirri-ornamented posterior nostril tube and long frilled rostral cirri. Data from additional material of the Australian N. marcidus McCulloch, 1926, are presented. A key is given to the five recognized species, a review of the genus is presented, and the systematic relationships of Neophrynichthys are discussed.

Dribbling of saliva in children with cerebral palsy and its management.

Drooling is a serious disability in cerebral palsy. Analysis of 50 such cases treated surgically has been reported. This study shows that drooling can be corrected by converting the anterior overflow into swallowing, and the posterior submucosal tube extension of the parotid duct considerably improved the results. In children under 3 years of age, or with minimal drooling or as a salvage, excision of the submandibular glands promises satisfactory results. Myotomy of the mylohyoid is indicated whenever open mouth deformity is present in such cases.

On the Life History of Lepoderma ramlianum Looss, 1896, and Its Development from a Xiphidiocercaria

During the course of investigations on Bilharzia infections among different snails, I came across a peculiar type of xiphidiocercariae liberated from Bulinus contortus. The cercariae were white in colour with elongated bodies and short stumpy tails. They were extremely sluggish and had a marked tendency to sink towards the bottom of the test tube. Specimens a few hours old, drawn from the tube, were surrounded with a rudimentary cyst wall and the tail was partially attached to them. The body was 0.57 mms. in length by 0.22 mms. in breadth. The tail was 0.3 mms. long in extended specimens. The oral sucker was 8o p in diameter and communicated with a well-developed pharynx leading to a thin oesophagus. This bifurcated, anterior to the ventral sucker into two intestinal ceca reaching as far posteriorly as the border of the body. The ventral sucker was 60 p in diameter. The surface of the body was covered with minute spines attaining their optimum size in the region of the oral sucker where they were arranged in concentric rows; then, they became sparsely distributed over the rest of the surface of the body. Its parenchyma was extremely cellular owing to the presence of numerous cystogenous glands, which obscured the minute details of the excretory system. On either side of the body, there were three stylet glands (fig. 3). Each had a separate duct opening in the vicinity of the stylet. This structure (fig. 4) was thin and fragile. It was partially embedded in the parenchyma of the oral sucker, had no marked shoulders and measured 40 p in length; the spine being onefourth the total length of the stylet. The excretory system (fig. 3) comprised two tubes; the anterior tube received two groups of tributaries, each with a couple of flame cells which drained the regions of the oral and ventral suckers. The posterior tube received a group of tributaries with three flame cells and another with a single flame cell. Both groups drained the region posterior to the ventral sucker. The two tubes joined each other at the level of the posterior margin of the ventral sucker, forming a thick main tube. The main tube from either side opened directly into the excretory vesicle, which received the main tributary from the tail, at its posterior margin. The formula of the excretory system would be 2 X (2 + 2) + (3 + I) I6. The cercariae developed in rediae (fig. i) about i mm. in length