Fibrovascular polyp of the oropharynx

Fibrovascular polyps are benign but rare tumours of the upper digestive tract. In most of the cases reported to date, fibrovascular polyps have originated from the oesophagus or hypopharynx. In 85-90 percent of these reports, the commonest site was adjacent to the cricopharyngeal muscle. We report a very rare case, the third in the English language literature, of a fibrovascular polyp arising from the oropharynx. The patient provided a history of coughing with regurgitation of the polyp, which caused respiratory discomfort that was only relieved by swallowing it. The patient was successfully treated by excision through the peroral route. There was no recurrence in the three years of follow-up. We also discuss the various diagnostic tests available and the pathogenesis and histopathology of such lesions.

Usefulness of percutaneously injected ethylene-vinyl alcohol copolymer in conjunction with standard endovascular embolization techniques for preoperative devascularization of hypervascular head and neck tumors: technique, initial experience, and correlation with surgical observations

BACKGROUND AND PURPOSE

Few reports have described the embolization of head and neck lesions by using direct percutaneous techniques. We report our preliminary experience in the direct percutaneous embolization of hypervascular head and neck tumors by using Onyx in conjunction with standard endovascular embolization techniques. We describe the technical aspects of the procedure and its efficacy in reducing intraoperative blood loss.

MATERIALS AND METHODS

We retrospectively studied 14 patients (3 females and 11 males; mean age, 33.4 years; range, 11-56 years) with 15 hypervascular tumors of the head and neck that underwent direct percutaneous embolization with Onyx in conjunction with particulate embolization. Nine paragangliomas and 6 JNAs underwent treatment. Documented blood loss was obtained from operative reports in these 15 patients with surgical resection performed 24-48 hours after the embolization.

RESULTS

Intratumoral penetration with progressive blood flow stasis was achieved during each injection. A mean of 3.1 needles (20-gauge, 3.5-inch spinal needle) were placed percutaneously into the lesion (range, 1-6). The mean intraoperative blood loss was 780 mL (range, <50-2200 mL). Near total angiographic devascularization was achieved in 13 of 15 tumors. There were no local complications or neurologic deficits from the percutaneous access or embolization of these hypervascular tumors.

CONCLUSIONS

In this study, the use of percutaneous injected Onyx in conjunction with standard endovascular embolization techniques in patients with hypervascular head and neck tumors seemed to enhance the ability to devascularize these tumors before operative removal.

System-level analysis of tryptophan regulation in Escherichia coli--performance under starved and well-fed conditions

Biological systems respond appropriately to a variety of environments thus representing complex systems with rich physiological behaviour. Quantitative models can be used to identify the design components that result in the system complexity. In this work, the tryptophan system of Escherichia coli that synthesises tryptophan internally when faced with starvation in a rapid manner and shuts off the synthesis sluggishly when the cells are exposed to a medium replete with tryptophan has been discussed. The evolved regulatory design is capable of providing such an asymmetric response that represents an appropriate behaviour to ensure survival. The tryptophan system uses three distinct regulatory mechanisms namely genetic regulation, transcriptional attenuation and enzyme inhibition to achieve its goals. It has been shown that genetic repression and attenuation are the only active regulatory mechanisms during moderate and severe starvation. However, as the degree of starvation increases, repression is relieved prior to attenuation. The analysis also shows that enzyme inhibition does not play a role under severe starvation and plays a marginal role in increasing the rate of repression when the cells are exposed to well-fed conditions. Finally, we use tools from linear systems theory to rationalise the above observations based on the poles and zeros of an approximated linear system.

Imaging of muscular denervation secondary to motor cranial nerve dysfunction

The effects of motor cranial nerve dysfunction on the computed tomography (CT) and magnetic resonance imaging (MRI) appearances of head and neck muscles are reviewed. Patterns of denervation changes are described and illustrated for V, VII, X, XI and XII cranial nerves. Recognition of the range of imaging manifestations, including the temporal changes in muscular appearances and associated muscular grafting or compensatory hypertrophy, will avoid misinterpretation as local disease. It will also prompt the radiologist to search for underlying cranial nerve pathology, which may be clinically occult. The relevant cranial nerve motor division anatomy will be described to enable a focussed search for such a structural abnormality.

Acute toxicity of heavy metals to acetate-utilizing mixed cultures of sulfate-reducing bacteria: EC100 and EC50

Acid mine drainage from abandoned mines and acid mine pit lakes is an important environmental concern and usually contains appreciable concentrations of heavy metals. Because sulfate-reducing bacteria (SRB) are involved in the treatment of acid mine drainage, knowledge of acute metal toxicity levels for SRB is essential for the proper functioning of the treatment system for acid mine drainage. Quantification of heavy metal toxicity to mixed cultures of SRB is complicated by the confounding effects of metal hydroxide and sulfide precipitation, biosorption, and complexation with the constituents of the reaction matrix. The objective of this paper was to demonstrate that measurements of dissolved metal concentrations could be used to determine the toxicity parameters for mixed cultures of sulfate-reducing bacteria. The effective concentration, 100% (EC100), the lowest initial dissolved metal concentrations at which no sulfate reduction is observed, and the effective concentration, 50% (EC50), the initial dissolved metal concentrations resulting in a 50% decrease in sulfate reduction, for copper and zinc were determined in the present study by means of nondestructive, rapid physical and chemical analytical techniques. The reaction medium used in the experiments was designed specifically (in terms of pH and chemical composition) to provide the nutrients necessary for the sulfidogenic activity of the SRB and to preclude chemical precipitation of the metals under investigation. The toxicity-mitigating effects of biosorption of dissolved metals were also quantified. Anaerobic Hungate tubes were set up (at least in triplicate) and monitored for sulfate-reduction activity. The onset of SRB activity was detected by the blackening of the reaction mixture because of formation of insoluble ferrous sulfide. The EC100 values were found to be 12 mg/L for copper and 20 mg/L for zinc. The dissolved metal concentration measurements were effective as the indicators of the effect of the heavy metals at concentrations below EC100. The 7-d EC50 values obtained from the difference between the dissolved metal concentrations for the control tubes (tubes not containing copper or zinc) and tubes containing metals were found to be 10.5 mg/L for copper and 16.5 mg/L for zinc. Measurements of the turbidity and pH, bacterial population estimations by means of a most-probable number technique, and metal recovery in the sulfide precipitate were found to have only a limited applicability in these determinations.

Nasal septal perforation in a patient with allergic bronchopulmonary aspergillosis and rhinitis on long term corticosteroids

A 22-year-old male, referred to us as a case of multi-drug resistant tuberculosis was diagnosed as allergic bronchopulmonary aspergillosis (ABPA) after serological and computed tomography confirmation. He was initiated on oral as well as inhaled corticosteroids along with nasal corticosteroid spray for his nasal complaints. One year subsequently, he developed a nasal septal perforation. Biopsy taken from the site did not reveal any granulomatous or atrophic changes and cultures of the biopsy did not yield any organism. The septal defect, repaired surgically by Hazeltine's method healed completely within 6 weeks. There have been anecdotal reports of septal perforation in patients with rhinitis on intranasal corticosteroids but hitherto not in patients with ABPA. A periodic examination of the nasal septum should be undertaken in patients with ABPA and rhinitis on long term inhaled oral and intranasal corticosteroids along with oral corticosteroids.

Effect of intraesophageal acid instillation on airway reactivity in patients with asthma

OBJECTIVE

To study the change in airway reactivity due to presence of acid in lower esophagus and its reversibility by antacid.

METHOD

In this double blind study 12 subjects with asthma and gastroesophageal reflux received acid (N/10 hydrochloric acid) and antacid (mixture of magnesium trisilicate and aluminum hydroxide) perfusion in lower esophagus via a nasogastric tube. The four combinations were antacid-antacid (control), antacid-acid, acid-antacid and acid-acid. Airway reactivity (Histamine PD20) was recorded after each perfusion.

RESULTS

Histamine PD20 significantly decreased (airway reactivity increased) (p < 0.05) with all three combinations containing acid as compared to control. No significant difference in airway reactivity was observed if the antacid was given before or after the acid.

CONCLUSION

Presence of acid in lower esophagus can increase airway reactivity. This effect lasts longer than the presence of acid in esophagus itself.

The relationship between the theory of evolution and the social sciences, particularly psychology

The application of the theory of evolution to human social behavior has, along with some illumination, produced friction that occasionally bursts into flame. In this paper we will examine the relationship between the theory of evolution and the social sciences, psychology in particular. We will identify some of the sources of friction between proponents and opponents of applying evolutionary theory to the social sciences, and we will suggest that listening carefully to both sides in the debate points the way to an enriched understanding of human social behavior.

Inhibition of hepatitis C virus (HCV)-RNA-dependent translation and replication of a chimeric HCV poliovirus using synthetic stabilized ribozymes

Ribozymes are catalytic RNA molecules that can be designed to cleave specific RNA sequences. To investigate the potential use of synthetic stabilized ribozymes for the treatment of chronic hepatitis C virus (HCV) infection, we designed and synthesized hammerhead ribozymes targeting 15 conserved sites in the 5' untranslated region (UTR) of HCV RNA. This region forms an internal ribosome entry site that allows for efficient translation of the HCV polyprotein. The 15 synthetic ribozymes contained modified nucleotides and linkages that stabilize the molecules against nuclease degradation. All 15 ribozymes were tested for their ability to reduce expression in an HCV 5' UTR/luciferase reporter system and for their ability to inhibit replication of an HCV-poliovirus (HCV-PV) chimera. Treatment with several ribozymes resulted in significant down-regulation of HCV 5' UTR/luciferase reporter expression (range 40% to 80% inhibition, P <.05). Moreover, several ribozymes showed significant inhibition (>90%, P <.001) of chimeric HCV-PV replication. We further show that the inhibitory activity of ribozymes targeting site 195 of HCV RNA exhibits a sequence-specific dose response, requires an active catalytic ribozyme core, and is dependent on the presence of the HCV 5' UTR. Treatment with synthetic stabilized anti-HCV ribozymes has the potential to aid patients who are infected with HCV by reducing the viral burden through specific targeting and cleavage of the viral genome.

Decreased and aberrant nuclear lamin expression in gastrointestinal tract neoplasms

BACKGROUND

Altered expression of lamins A/C and B1, constituent proteins of the nuclear lamina, may occur during differentiation and has also been reported in primary lung cancer.

AIMS

To examine the expression of these proteins in gastrointestinal neoplasms.

PATIENTS

Archival human paraffin wax blocks and frozen tissue from patients undergoing surgical resection or endoscopic biopsy.

METHODS

Immunohistochemistry and western blotting using polyclonal antisera against A type lamins and lamin B1.

RESULTS

The expression of lamin A/C was reduced and was frequently undetectable by immunohistochemistry in all primary colon carcinomas and adenomas, and in 7/8 primary gastric cancers. Lamin B1 expression was reduced in all colon cancers, 16/18 colonic adenomas, and 6/8 gastric cancers. Aberrant, cytoplasmic labelling with both antibodies occurred in some colonic cancers and around one third of colonic adenomas. Cytoplasmic lamin A/C expression was detected in 3/8 gastric cancers. Lamin expression was reduced in gastric dysplasia, but not intestinal metaplasia, atrophy, or chronic gastritis. Lamin expression was low in carcinomas of oesophagus, prostate, breast, and uterus, but not pancreas.

CONCLUSIONS

Reduced expression of nuclear lamins, sometimes together with aberrant, cytoplasmic immunoreactivity is common in gastrointestinal neoplasms. Altered lamin expression may be a biomarker of malignancy in the gastrointestinal tract.