Occlusion Of Tract Research Articles

Technical modifications for improving the success rate of PEG tube placement in patients with head and neck cancer

Background: Patients with head and neck cancer (HNC) benefit from nutritional support by means of PEG tubes, but endoscopy may be impossible when there is partial or complete trismus and/or stenosis or occlusion of the upper aerodigestive tract. Methods: PEG tubes were placed in 277 patients with HNC. Oral insertion of an endoscope into the esophagus was impossible in 27 patients. Transnasal endoscopy was performed (n = 4). In the cases of high-grade tumor obstruction, the endoscope was introduced into the esophagus through a straight laryngoscope (n = 9). When upper aerodigestive tract occlusion was present, endoscopy with PEG placement was successfully performed during surgery by means of the opened pharynx after tumor resection (n = 12). Results: In 25 of the 27 cases PEG tubes could be placed by using the above alternative techniques. There were no immediate complications, and no complications occurred within 30 days of PEG placement. Conclusions: Transnasal, straight laryngoscopic, or intraoperative open endoscopy can improve the success rate for PEG tube placement in patients with HNC.

Effect of fibrin glue occlusion of the hepatobiliary tract on thioacetamide-induced liver failure

Background: Expression and activation of hepatocyte growth factor (HGF) is stimulated by a complex system of interacting proteins, with thrombin playing an initial role in this process. The impact of temporary occlusion of the hepatobiliary tract with fibrin glue (major component thrombin) on the HGF system in acute and chronic liver damage in a rat model was investigated. Methods: Chronic liver damage was induced in 40 rats by daily intraperitoneal application of thioacetamide (100 mg/kg) for 14 days. After 7 days half of them received an injection of 0.2 mL fibrin glue into the hepatobiliary system. Daily intraperitoneal administration of thioacetamide continued for 7 consecutive days. The rats were then sacrificed for blood and tissue analysis. Acute liver failure was induced in 12 rats by intraperitoneal administration of a lethal dose of thioacetamide (500 mg/kg per day for 3 days) after an injection with 0.2 mL fibrin glue into their hepatobiliary tract. Survival rates and histological outcome were investigated and compared with control animals. Results: Fibrin glue occluded rats showed significantly lower liver enzyme activities and serum levels of bilirubin, creatinine and urea nitrogen. Immunohistochemistry revealed a significant increase in c-met-, HGFα- and especially HGFβ-positive cells. Rats subjected to a lethal dose of thioacetamide survived when fibrin glue was applied 24 hours prior to the toxic challenge. These animals showed normal liver structure and no clinical abnormalities. Conclusion: Fibrin glue occlusion of the hepatobiliary tract induces therapeutic and prophylactic effects on chronic and acute liver failure by stimulating the HGF system. Therefore, fibrin glue occlusion might be useful in treating toxic liver failure.

The VOT of the Hungarian Voiceless Plosives in Words and in Spontaneous Speech

Due to the various techniques used in experimental phonetics and the language inventories, more and more has been learned about the nature of stops of the world's languages. Stop consonants occur in all languages, with voiceless unaspirated stops being the most common. The differences in voice onset time (VOT) have been termed lead vs. short lag, where VOT itself is defined as the timing between the onset of phonation and the release of the occlusion of the vocal tract.

Acoustic impedance of an artificially lengthened and constricted vocal tract

Voice training techniques often make use of exercises involving partial occlusion of the vocal tract, typically at the anterior part of the oral cavity or at the lips. In this study two techniques are investigated: a bilabial fricative and a small diameter hard-walled tube placed between the lips. Because the input acoustic impedance of the vocal tract is known to affect both the shaping of the glottal flow pulse and the vibrational pattern of the vocal folds, a study of the input impedance is an essential step in understanding the benefits of these two techniques. The input acoustic impedance of the vocal tract was investigated theoretically for cases of a vowel, bilabial occlusion (fully closed lips), a bilabial fricative, and artificially lengthening the tract with small diameter tubes. The results indicate that the tubes increase the input impedance in the range of the fundamental frequency of phonation by lowering the first formant frequency to nearly that of the bilabial occlusion (the lower bound on the first formant) while still allowing a continuous airflow. The bilabial fricative also has the effect of lowering the first formant frequency and increasing the low-frequency impedance, but not as effectively as the extension tubes.

Refractory abdominal-cutaneous fistulas or leaks: percutaneous management with a collagen plug.

We report the results of abdominal-cutaneous fistula tract occlusion with a collagen plug in a series of patients with fistulas or leaks refractory to conservative therapy. Seven patients were found to have persistent fistula or leak after percutaneous drainage of abdominal pelvic fluid collections. All patients but one were refractory to surgical or percutaneous drainage. Under fluoroscopic guidance, modified Vasoseal (Datascope Inc, Montvale, NJ) collagen plugs were deployed into the fistulas using catheter-directed techniques. The plugs were split longitudinally to fit into an 8F or 9F peel-away sheath, placed into the fistula, and deployed. Results were tabulated and patients were followed up. Six of seven patients undergoing fluoroscopically guided, catheter-directed tract occlusion had resolution of the fistula, with no evidence of fistula or abscess recurrence from 30 to 180 days after closure. There were no procedural complications. The technique was unsuccessful in dosing a gastrocutaneous fistula after removal of a large-bore gastrostomy tube; this failure was believed to be secondary to the short length and large caliber of the tract in a patient with hypercortisolemia. Closure of abdominal-cutaneous fistula tracts by occlusion with a modified Vasoseal collagen plug shows promise in the management of fistulas refractory to catheter drainage.

Ventricular-vascular uncoupling by acute conotruncal occlusion in the stage 21 chick embryo.

Embryonic ventricular diastolic and systolic function was evaluated during normal ejection (coupled) and during acute ventricular outflow tract occlusion (uncoupled) in the stage 21 chick embryo. We simultaneously measured ventricular pressure with a servo-null system and ventricular dimensions using video microscopy. Experimental protocols included 1) baseline recording followed by acute conotruncal (CT) ligation (n = 15) and 2) baseline recording, preload increase using Krebs-Henseleit buffer (3 microliters), preload reduction via venous hemorrhage, and then CT occlusion (n = 20). Ventricular epicardial cross-sectional area was converted to internal volume using wall volume measures and assuming an ellipsoid geometry to produce pressure-volume loops. We calculated the time constant of ventricular pressure decline using a monoexponential decay function with a pressure asymptote. As previously noted, heart rate was unaffected by acutely altered preload or afterload. CT ligation increased end-systolic pressure, maximal +dP/dt, and the time constant of ventricular pressure decline and decreased stroke volume indexed for end-diastolic volume. Thus the embryonic ventricle has significant contractile reserve masked in vivo by the dynamic coupling between the ventricle and arterial circulation.

Stent-Grafts for Revision of TIPS Stenoses and Occlusions: A Clinical Pilot Study

To assess the clinical and technical results of stent-graft placement for revision of transjugular intrahepatic portosystemic shunt (TIPS) stenoses and occlusions. Six patients who developed recurrent TIPS stenosis or occlusion of the parenchymal tract underwent shunt revision with use of polytetrafluoroethylene (PTFE) stent-grafts anchored at both ends by Z stents and centrally supported by Wallstents. Before graft placement, mean primary patency was 50 days (range, 9-100 days). Patients underwent one to eight revisions with angioplasty or stent placement (mean, 3.2). Three patients had biliary-TIPS fistulas documented with use of a prototype double occlusion balloon catheter. Stent-grafts were successfully placed within the obstructed shunt, creating an excellent lumen in all cases. The portosystemic gradient was decreased from a mean of 24.3 mm Hg (range, 12-35 mm Hg) to a mean of 10.3 mm Hg (range, 7-16 mm Hg). Five of six patients were asymptomatic and no complications occurred (median clinical follow-up, 331 days). One patient died of pre-existing multi-organ system failure. The duration of primary patency after stent-grafting was improved (mean, 229 days; range, 27-324 days) and the difference approached statistical significance despite the small sample size (P = .056, paired t test). Three patients remained primarily patent at a mean venographic follow-up of 315 days. One shunt occluded at 1 month from residual thrombus in the portal vein, and one stenosis occurred that was secondary to misplacement of the original stent-graft. Patency was re-established in each of these patients. PTFE covered stent-grafts are effective for shunt revision in patients with tract stenosis or occlusion and appear to improve TIPS patency.

Animal model of the univentricular heart and single ventricular physiology.

The univentricular heart complexes are a fairly common and potentially lethal set of congenital cardiac anomalies. Progress in developing new therapeutics has been hampered by a lack of suitable animal models. The authors developed a stable, closed heart preparation to systematically examine potential interventions. Using neonatal piglets (3.5-6.0 kg), a 6-mm PTFE graft was anastomosed end to end to the innominate artery and end to side to the pulmonary artery. An atrial septostomy was made, using a Rashkind septostomy catheter passed transvenously. With the same catheter, the tricuspid valve was rendered incompetent. Occlusion of the right ventricular outflow tract completed a univentricular circuit. All cardiac output exited from the left ventricle, and pulmonary blood flow was maintained via the innominate artery-to-pulmonary artery shunt. Pressure transducers measured central venous (mid inferior vena cava), aortic, and pulmonary arterial pressures. Oximetric probes recorded systemic venous and arterial oxygen saturations. Transit-time flow probes measured total cardiac output and pulmonary flows. Systemic flow was calculated by subtracting pulmonary flow from total cardiac output. This model has been completed in 30 animals. Minimal pressure drops have been recorded across the innominate-to-pulmonary artery graft. Pulmonary flows up to 700 +/- 52 mL/min were seen. Total cardiac outputs are as high as 1370 +/- 88 mL/min. Mean ratios of pulmonary to systemic flow (Qp/Qs ratio) range from 1.29 +/- 0.08 to 0.41 +/- 0.09. The model allows for full continuous monitoring of systemic and pulmonary pressures and flows and for accurate characterization of the physiological effects of respiratory and pharmacological interventions. In addition, mechanical constriction of the graft may allow direct alteration of the Qp/Qs ratio, with determination of an optimum value for this ratio.

ＴＩＰＳＳ施行後のＴＩＰＳＳ路と門脈の閉塞の治療にＤ‐ＢＲＴＯが有効であった孤立性胃静脈りゅう合併肝硬変の１例

肝硬変(LC)による孤立性胃静脈瘤(Lg-f)に対する治療法として近年Transjugular Intrahepatic Portosystemic Stent Shunt (TIPSS)に加え,Balloon occluded retrograde transvenous obliteration (BRTO)も行われている.我々はLg-fの治療のために実施したTIPSS後に発生したTIPSS路と門脈(PV)の閉塞にBRTOが有効であった1例を経験したので報告する.症例は68歳,女性.肝硬変症.Lg-fに対してTIPSS施行後,TIPSS路とPVの閉塞,Lg-fの再燃をきたし,DSAではPV本幹からTIPSS路の閉塞を認めた.胃腎短絡路(GR-S)形成による門脈血流の減少によりPVとTIPSS路の閉塞をきたしたと推測された.GR-S血流をPV本幹,TIPSS路方向に変更し,PVの再疎通とLg-fの改善を目的にTIPSS路とGR-SからDouble BalloonによるBRTO (D-BRTO)とTIPSS路のPercutaneous Transluminal Angioplasty (PTA)を施行した.D-BRTO施行後,Lg-fは改善しPV本幹も再疎通し合併症も認められなかった.Lg-fに対するTIPSS施行後に発生したPV, TIPSS路の閉塞の再疎通にD-BRTOは合併症も少なく有用であった.

Intraductal hepatocellular carcinoma treated by intralumenal brachytherapy

Hepatocellular carcinoma (HCC) rarely presents as biliary tract occlusion [1,2]. Intralumenal iridium-192 brachytherapy has been used to treat extrahepatic bile duct carcinoma and may be curative if the macroscopic tumour has been resected surgically [3]. We describe a rare event, a case of HCC presenting with bilary tract occlusion treated with intralumenal iridium-192 brachytherapy.

Local intraarterial thrombolysis for acute stroke in the carotid artery territories.

We have tested the feasibility of local intraarterial thrombolytic therapy in ischemic stroke in the carotid artery territories observed within 5 h of the onset of symptoms. Only 5 of 615 consecutive patients were enrolled. They were 1 man and 4 women aged 50 to 75 years. Angiography disclosed occlusion of the M2 tract in one, of the M3 tract in one, of the carotid siphon in one of M4 tract in two. Intraarterial urokinase was infused at a mean dosage of 560,000 units close to the site of occlusion. Four of them had partial or complete recanalisation at early angiographic control and were independent at 6th month control. The one who did not demonstrate recanalisation was confined to a wheelchair. One patient, who had recanalisation, sustained a hemorrhagic transformation of the brain ischemia not interfering with outcome. Our experience, at the light of the low rate of enrollment, despite the results, suggest that intraarterial thrombolysis may be a therapeutic tool for selected patients with stroke in the carotid artery territories and not a routinary treatment for them.

Complete Occlusion of the Intestinal Tract with Staples

Iatrogenic transmural knife wounds of the duodenum, proximal jejunum, distal ileum, and right colon were made in pigs. In order to assure healing of the repair, the intestinal lumen proximal to the iatrogenic injury was purposefully occluded with staples and gastrointestinal content was diverted proximally. Our results showed that 9 of 9 intestinal lumens closed in continuity (with one application of two rows of zig-zag staples) became patent by day 62 (range 11–62, median = 35). This technical approach was utilized successfully in a patient with a bleeding and necrotic giant ulcer of the duodenum and head of the pancreas associated with high output pancreatic fistula.

Cyromazine-induced effects on the larval cuticle of the sheep blowfly, Lucilia cuprina: Ultrastructural evidence for a possible mode of action

Cyromazine inhibits development and ecdysis of larval Lucilia cuprina (Wiedemann). This study details unique changes induced by cyromazine in the ultrastructure of the cuticle of the body, foregut, and hindgut. Apolysis and, ultimately, ecdysis are severly disrupted or inhibited in affected larvae. However procuticle continues to be secreted by the epidermal cells of body and foregut, resulting in a gross thickening of the cuticle. The cuticle of severely affected larvae is traversed by disoriented microfibrils and is also subject to abnormal sclerotization and melanization. Despite the disruption of ecdysis, new cuticle is secreted under the old one in treated larvae. In extreme cases, this results in the occlusion of the digestive tract by cuticle from two instars. This study supports previous conclusions that cyromazine does not act by inhibiting chitin formation. It is suggested that the primary mode of action of cyromazine is via the hormonal system.

Azoospermies à FSH plasmatique normale et carnitine séminale non abaissée : une double signification. Implications diagnostiques et thérapeutiques

In secretory azoospermia, plasma FSH is usually high and seminal carnitine in relation with epididymal secretion, normal. In excretory azoospermia, FSH is not increased and seminal carnitine is lowered. Here we report the case of 23 patients in whom FSH was not increased and seminal carnitine not decreased. Among these patients 17 had had surgery with vas deferens and epididymis exploration. Testis biopsy for histological analysis was performed. It turned out that most of the patients (13 of the 17) had a genital tract occlusion located at the junction of corpus--caput of the epididymis (9/13) or at the junction testis-epididymis (4/13). The 4 remaining patients showed arrest of spermatogenesis which was before spermiogenesis in 3 of the 4 cases. This study allows (1) to define the diagnosis value of the seminal carnitine assay, which remains the only test to affirm excretory azoospermia when there is a bilateral occlusion located on the genital tract between the epididymis corpus and the ejaculatory ducts, (2) to consider another treatment than epididymo-vasostomy in cases of occlusion caput--corpus (epididymo-epididymostomy), (3) to detect a population presenting a very early arrest of spermatogenesis without any pituitary effect, probably having a special regulation of FSH secretion.

Fetal surgery for obstructive uropathy: rational considerations.

The widespread use of high resolution dynamic ultrasound imaging methods in obstetrics now permits recognition of structural and/or functional developmental anomalies of fetal genitourinary tract with some considerable accuracy. Detection of congenital obstructive uropathy in the human fetus may occur as early as 16 weeks gestation. In the fetal lamb model, experimental occlusion of the outflow tract results in progressive hydronephrosis, pulmonary hypoplasia, and oligohydramnios. The renal parenchymal changes vary with the fetal age at obstruction ranging from simple hydronephrosis with later obstruction to dysgenesis with earlier obstruction. The pulmonary damage, and to some extent the renal damage, may be halted or even reversed with release of obstruction. These advances in diagnosis and an understanding of the pathophysiology have prompted attempts at chronic in utero diversion therapy in the human fetus with obstructive uropathy yielding encouraging, but as of yet, unproven success. In this report, the methods for such therapy, the rationale for the therapy, and the results of the therapy is reviewed.

Zum Erstickungstode beim Verschlu� der Atem�ffnungen durch Sand

Eleven cases are reported in which death occurred because of suffocation as a result of occlusion of the respiratory tract by sand (without thoracic compression: 3 cases) or being buried alive (8 cases). Two tables demonstrate the findings and circumstances in the events. Three cases are described in detail. A 22-year-old woman was manhandled by blows and kicks to the head and neck. She became unconscious and her head and neck were covered by a layer of sand so that she suffocated. A 42-year-old man was smothered, while unconscious, in a prone position with his face in the sand, after hard blows to the head by two culprits. A 17-year-old girl finally died by chocking. Previously the culprit had pressed her face into the ground, so that she aspirated particles of soil. The question of vital reactions during aspiration of sand was investigated by microscopic examination of the content of the air passage and by destroying parts of the lungs by sulphuric acid. Minimal aspiration of sand occurred in all cases. Although the postmortal remains were left in the ground, there was no postmortem penetration of sand into the air passage. Histological examinations were carried out to support the diagnosis of violent suffocation. In some cases, there were remarkable findings (mobilization of alveolar cells, hepatocelullar hydropic degeneration), but there were no typical or unanimous findings that pertained to all cases.

Ascaris suum: Continuous perfusion of the pseudocoelom and nutrient absorption

A double-cannulation apparatus was constructed for continuous perfusion of the pseudocoelom of adult Ascaris suum while maintaining the intact parasite in a controlled incubation chamber. Peristaltic pumps maintained a constant flow rate of artificial perienteric fluid through the incubation chamber (1 ml/min) and through the parasite (100 μl/min). Based on protein determinations, perienteric fluid was removed from the pseudocoelom within 35 min of initiation of perfusion (3.5 ml). A nonabsorbable dye, Blue Dextran, was detected first in the perfusate 4 min (400 μl) after initiation of infusion into the pseudocoelom, and was maintained at a constant concentration in the perfusate by 8 min after initiation of dye infusion. Removal of the dye from the pseudocoelom was accomplished within 8 min (800 μl) after the cessation of dye infusion. Occlusion of the digestive tract had no effect ( P < 0.05) on the short-term (3 hr) absorption of 3H-labeled cholesterol, [ 14C]-3- o-methylglucose or [ 14C]glucose from the incubation medium into the perienteric cavity. Concentrations of isotopes in the pseudocoelom reached steady-state levels within 60 min of the initiation of incubation, but remained low (>0.5%) when compared to medium concentration. Similarly, the time course of the accumulation of [ 14C]glucose into individual tissue components did not differ in intact worms with or without patent intestinal tracts. Thus, the cuticular/muscle tissue largely appears to be the primary route of absorption of cholesterol and glucose in adult A. suum. The cannulation and perfusion procedure for A. suum is an adaptable system for continual or intermittent measurements of internal physiological processes, in particular, the absorption and metabolism of nutrients. Furthermore, this system permits simple modification for “closed-loop” perfusion or internal delivery of select compounds.

Right ventricular performance during increased afterload impaired by hypercapnic acidosis in conscious dogs.

Since heart failure may occur in the setting of lung dysfunction and CO2 retention with only modest increases in cardiac work load, we questioned whether myocardial function is impaired by hypercapnic acidosis. To determine the influence of hypercapnic acidosis on right ventricular function, we measured the effects of acute (2 hours) and chronic (2 weeks) hypercapnic acidosis on right ventricular performance during normal and increased right ventricular afterload in five conscious dogs. Systemic hemodynamic and right ventricular functions were unaltered during normal right ventricular afterload by acute hypercapnic acidosis (PaCO2 = 49 +/- 3 mm Hg, pH = 7.27 +/- 0.003). As right ventricular afterload was increased by progressive balloon occlusion of the right ventricular outflow tract during acute hypercapnic acidosis, the rise (slope) in right ventricular end-diastolic pressure was increased 4-fold (P less than 0.01) over that observed in normocapnic control. Maximum isovolumic right ventricular dP/dt rose (P less than 0.05) comparably with increasing right ventricular afterload during normocapnic control and acute hypercapnic acidosis. Chronic hypercapnic acidosis (PaCO2 = 55 +/- 2 mm Hg, pH = 7.28 +/- 0.01) resulted in systemic vasodilation and increased (P less than 0.05) heart rate and cardiac output during normal right ventricular afterload. As right ventricular afterload was increased during chronic hypercapnic acidosis, the rate of rise in right ventricular end-diastolic pressure was 2-fold (P less than 0.01) above normocapnic control but maximum isovolumic right ventricular dP/dt was unchanged in contrast to normocapnic control and acute hypercapnic acidosis. Moreover, cardiac output fell and stroke work was unchanged with increasing afterload during chronic hypercapnic acidosis. beta-Adrenergic blockade resulted in an increased (P less than 0.01) rate of rise in right ventricular end-diastolic pressure with afterload during normocapnic control and chronic hypercapnic acidosis. We conclude that hypercapnic acidosis results in diminished right ventricular performance during increased right ventricular afterload, evidenced by accentuated rise in right ventricular end-diastolic pressure, and may contribute to the congestive heart failure and edema observed in patients with pulmonary hypertension and CO2 retention.

Dynamic Control of a Computer Model of the Vocal Cords

Dynamic, time-varying controls are implemented for a vocal-cord model described earlier [Bell System Tech. J. 51, 1233–1268 (1912)]. A speech synthesis system is formulated from the cord-model, a programmed vocal tract, and a control mechanism. Time-varying controls in the simulation include subglottal pressure, cord tension, glottal area at rest, and vocal-tract shape. Previously reported physiological data on muscle electromyography, air flow, and lung pressure are used to estimate control correlates in the computer model. For voicing at constant subglottal pressure and with an unoccluded vocal tract, the rest-area of cord opening is found to be the dominant factor in voiced/voiceless control. Asymmetry in onset and cessation of voicing is found to relate to direct observations of cord motion. Cord tension is dominant in pitch control. Time variations in lung pressure and in tract occlusion modify these control factors. A computer movie is presented to illustrate the dynamic control and behavior of the model.

A method for recording the effects of anthelmintics on the movements of Ascaris lumbricoides.

Adult roundworms (Ascaris lumbricoides) obtained from pigs were suspended in modified Tyrode solution at 37 degrees in fine nylon stockings, and the movements of the stockings were recorded. This method of suspension avoided damage to the cuticle or occlusion of the alimentary tract of the worm.Piperazine salts caused gradual narcosis, the time of onset of which was related linearly to the logarithm of the concentration of drug in the bath. The method is suitable for the assay of preparations of piperazine. Tetrachlorethylene, hexylresorcinol, and oil of chenopodium all caused stimulation of movement before the worm was immobilized. Santonin caused incoordination of the movements of the anterior end of the worm; the movements of the body were apparently unaffected. Piperazine is the safest preparation available for the treatment of ascariasis.