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PubMed2005

[Surgical technique of endonasal micro-endoscopic operation in patients with massive and recurrence nasal polyposis--own experience].

The author presents modification of the well-known surgical techniques used in endonasal optically aided operations in the patients with massive and recurrent nasal polyposis. After septal correction the attachment of the middle turbinate and lower turbinate is identified. It helps to find an appropriate place to open a maxillary sinus through uncinectomy. Opened maxillary sinus makes possible to find orbital lamella. The posterior maxillary sinus wall as the anatomic point helps to find the anterior wall of sphenoid sinus through posterior ethmoidectomy. After finding choane it is possible to open sphenoid sinus without cutting the posterior part of the middle turbinate. From this part it is possible to continue the operation like in the posterior-to-anterior technique, because it is well known where is the ethmoid roof. The operation is finished after opening frontal recess and correction of the middle turbinate. I did 110 total endonasal sphenoethmoidectomies using this technique in the patients with massive and recurrent nasal polyposis without any serious complications. I didn't have any problems with orientation in operative field even in very complicated cases.

Endoscopy↗
PubMed1983

Virulence of Pasteurella multocida in atrophic rhinitis of gnotobiotic pigs infected with Bordetella bronchiseptica.

Bordetella bronchiseptica and Pasteurella multocida have been impLicated in the aetiology of atrophic rhinitis of pigs but the precise cause and pathogenesis of field outbreaks have still to be clarified. The virulence of 11 strains of P multocida was investigated by intraperitoneal injection of culture filtrates in BALB/C mice, or by infection of gnotobiotic piglets given B bronchiseptica five days previously. Three of four type D strains of P multocida were lethal for mice and caused severe turbinate lesions and shortening of the snout with B bronchiseptica in gnotobiotic pigs; large numbers of P multocida and B bronchiseptica persisted for 64 days in the nasal cavity of these pigs. The fourth strain caused moderately severe turbinate lesions in gnotobiotic pigs infected with B bronchiseptica; small numbers of P multocida were found in these pigs and the lesions were attributed mainly to B bronchiseptica. Filtrates from seven strains of P multocida (four type A and three type D) were not lethal for mice and these strains with B bronchiseptica caused moderately severe turbinate lesions in gnotobiotic pigs; five of them colonised the nasal cavity reasonably well for 35 days but the lesions were attributed mainly to B bronchiseptica. The turbinate bones had regenerated by 64 days in pigs given type A strains of P multocida whereas the lesions persisted in pigs given type D strains. Antibodies to P multocida were detected in sera from infected gnotobiotic pigs by acid agglutination but not by indirect haemagglutination tests; neutralising activity to the mouse lethal toxin was detected in serum from one of five piglets at 64 days. The lethal toxin was inactivated at 56 degrees C for 30 minutes, by incubation with protease K for two hours and by 0.2 per cent formalin for 18 hours at 37 degrees C but not by trypsin; it was precipitated by 30 to 40 per cent saturation with ammonium sulphate and remained in the supernatant after centrifugation at 150,000 g. It was concluded that infection with virulent, type D strains of P multocida and B bronchiseptica could explain severe outbreaks of atrophic rhinitis; large numbers of both organisms persisted in the nasal cavity of gnotobiotic pigs with severe lesions; and that a soluble, heat-labile toxin may be an important virulence determinant in the type D strains of P multocida that cause severe atrophic rhinitis.

Animals↗
PubMed1980

Experiences in middle turbinectomy.

Rhinologists have long cautioned about removal of the middle turbinate, though exenteration of the ethmoid labyrinth including the middle turbinate has shown the structure can be sacrificed. The middle turbinate can be removed in the crowded nose often with septoplasty and partial inferior turbinectomy, to improve the nasal airway. A vasoactive middle turbinate which engorges and compresses against an often deviated nasal septum gives rise to the "four finger headache" patient for whom middle turbinectomy, often with septoplasty, is helpful. Point cocainization of the compressed site helps prognosticate the good candidate for surgical relief. Patients with purulent sinusitis have been excluded from the study. Results have been good to excellent with no long-term adverse sequelae. There has been no crusting, drying, or infection as a result of our middle turbinectomies. Careful patient selection is critical.

Airway Obstruction↗
PubMed1998

Immunohistochemical localisation of tear lipocalin in human nasal mucosa.

Lipocalins are low molecular weight soluble proteins, a sub-class of this family are the odorant binding proteins (OBPs) which are postulated as having an important role in the perireceptor events of olfactory transduction, though their specific physiological function has yet to be defined. From the nasal mucus of normal subjects we recently isolated a 19kDa protein, the amino-acid sequence of which, limited to the first 20 residues, is identical to that of tear lipocalin. In this study we performed an immuno-histochemical investigation on the nasal localisation of this protein, using tissue specimens taken from the inferior (27 samples), middle (7 samples) and superior turbinates (6 samples) in 27 patients undergoing septoplastic surgery. The protein was detected in the sub-epithelial tubulo-acinar glands of the nasal mucosa, particularly in the mucoserous glands, in 74% of the specimens taken from the inferior turbinate, in 71.4% of those from the middle turbinate and in 66.6% of the samples of superior turbinate tissue. The homogeneous distribution of this protein in the nasal mucus could imply that it functions as a general protection agent rather than as an odour carrier or transducer.

Adolescent↗
PubMed1998

Isobutyraldehyde administered by inhalation (whole body exposure) for up to thirteen weeks or two years was a respiratory tract toxicant but was not carcinogenic in F344/N rats and B6C3F1 mice.

Isobutyraldehyde (a chemical structurally related to formaldehyde and used as a flavoring agent) was studied for toxicity and carcinogenicity by exposing male and female F344/N rats and B6C3F1 mice. Animals were exposed to isobutyraldehyde vapors 6 h per day, 5 days per week for up to 13 weeks or 2 years. In the 13-week studies, groups of 10 male and 10 female F344/N rats and B6C3F1 mice were exposed to concentrations of 0, 500, 1000, 2000, 4000, or 8000 ppm. Chemical-related body weight depression and deaths occurred in rats and mice exposed to 4000 and 8000 ppm. Necrosis of the epithelium accompanied with acute inflammatory reaction was observed in the nasal turbinate, larynx, and trachea of rats exposed to 8000 ppm. Exposure of rats to 4000 ppm resulted in metaplasia of the nasal respiratory epithelium, inflammation, degeneration of the olfactory epithelium, and osteodystrophy of the nasal turbinate bone. In the 13-week mouse study, exposure to 8000 ppm or 4000 ppm resulted in necrosis of the epithelium lining of the nasal turbinates. Osteodystrophy of the nasal turbinate bone and squamous metaplasia of the nasal respiratory epithelium were noted in mice exposed 4000 ppm. Degeneration of the olfactory epithelium was noted in males exposed 2000 ppm and in females exposed to 4000 ppm. In the 2-year studies, groups of 50 male and 50 male F344/N rats and B6C3F1 were exposed to concentrations isobutyraldehyde vapors of 0, 500, 1000, or 2000 ppm 6 h per day, 5 days per week. There were no differences in survival rates or mean body weights between exposed groups and control rats. Survival of male mice exposed to 2000 ppm and mean body weights of female mice exposed to 1000 or 2000 ppm were lower than those of the of the controls. No increase in neoplasm incidence was observed in rats and mice in the 2-year studies that could be attributed to isobutyraldehyde exposure. Chemical-related nonneoplastic lesions were limited to the nose of rats and mice. They included squamous metaplasia of the respiratory epithelium (rats), suppurative inflammation (rats), and olfactory epithelial degeneration (rats and mice) at 1000 and 2000 ppm.

Aldehydes↗
PubMed1996

A morphometric and functional study of the toxicity of atmospheric ammonia in the extrathoracic airways in pigs.

The effects of atmospheric ammonia (NH3) on the nasal and tracheal mucosa of pigs were investigated by morphometric and functional methods. Pigs were exposed to four concentrations of NH3 [5 (control), 25, 50 and 100 ppm] for 6 days in a specially designed air-pollutant exposure chamber. Samples were taken from the turbinates and the trachea, and the respiratory mucosa was examined by light and scanning electron microscopy. Dose-response curves to carbachol and isoproterenol were constructed using isolated strips of tracheal smooth muscle, with or without epithelium. In pigs exposed to ammonia, considerable mucosal injuries were observed in the turbinates but not in the trachea. The number of neutrophils in the epithelial layer and in the lamina propria, and epithelial hyperplasia were closely and significantly correlated with the concentrations of ammonia (r = 0.894, p < 0.001; r = 0.727, P < 0.001; and r = 0.818, p < 0.001, respectively). Except for the lamina propria, all these changes were significant (p < 0.05) at ammonia concentrations as low as 25 ppm. The percentage of the surface of the turbinate mucosa that was ciliated tended to decrease with increasing ammonia concentration (r = 0.439, p < 0.082). Ammonia induced smooth-muscle hyperresponsiveness to carbachol with a close linear correlation between individual values of the carbachol-induced maximal effect and the NH3 concentrations (r = 0.526, p < 0.003). While mechanical destruction of the epithelium induced an increase in Emax in the control group, no difference was observed between the intact and denuded strips from animals exposed to ammonia. The response to isoproterenol was not influenced by ammonia. It was concluded that quantitative histological analysis of the inflammatory infiltration and epithelial hyperplasia in the turbinates is a useful tool for quantifying the effects of atmospheric pollutants in pigs; a 6-day exposure to ammonia induces nasal irritation and functional disturbances of the tracheal smooth-muscle contractions at concentrations as low as 25 ppm.

Adrenergic beta-Agonists↗
PubMed1979

Protection of mice against virulent virus infection by a temperature-sensitive mutant derived from an HVJ (Sendai virus) carrier culture.

Experimental infection with HVJ (haemagglutinating virus of Japan-the Sendai strain of parainfluenza 1 virus) in mice was studied. Aerosol infection of newborn mice with the wild-type virus (HVJ-W) retarded the development of body weight and killed the animals within a few weeks. Large amounts of virus were isolated from both the lungs and the nasal turbinates of infected mice. In contrast, newborn mice exposed by inhalation to a temperature-sensitive (ts) mutant (HVJ-pB) derived from an HVJ carrier culture showed no clinical signs and grew equally well as mock-infected animals. No infectious virus could be recovered from the lungs although the ts mutant grew to moderate titre in the nasal turbinates. The prior inoculation of newborn mice with the ts mutant virus induced a state of significant resistance to subsequent challenge with the virulent wild-type virus. No replication of challenge virus in both lungs and nasal turbinates could be detected and the animals were protected a lethal infection. It is suggested that an avirulent temperature-sensitive mutant which has lost the capacity to replicate in the lower respiratory tract but is still capable of multiplying in the nasal turbinates may be a promising candidate for use in live vaccines especially against the infectious disease of the lower respiratory tract.

Animals↗
PubMed1993

Eosinophils in nasal polyps and nasal mucosa: an immunohistochemical study.

Immunohistochemical staining was performed at the time of endoscopic sinus surgery (ESS), after 6 months, and after 1 year on nasal polyps and biopsy specimens of the macroscopically unaffected mucosa of the middle and inferior turbinate bones of 46 patients with nasal polyps. During the follow-up period the patients were treated with topical corticosteroids. At time of ESS significantly more BMK13+ and EG1+ (pan eosinophil markers) and EG2+ (activation marker) eosinophils were found in the polyps than in the macroscopically unaffected mucosa of the middle and inferior turbinate bones of the patients. In the middle and inferior turbinate bones of 10 healthy subjects no EG2+ (activated) eosinophils were detected, whereas low-to-moderate numbers of BMK13+ and EG1+ eosinophils were seen in these specimens. This emphasizes that eosinophils play a role in the pathogenesis of nasal polyps. Compared with numbers at ESS, after 6 months and 1 year of follow-up, lower numbers of BMK13+, EG1+, and especially of EG2+ eosinophils were found in recurrences of polyps and in the macroscopically unaffected mucosa of the middle and inferior turbinate bones of the patients. The decrease in number of EG2+ (activated) eosinophils is an indication of a reduced local inflammatory reaction, and could be an important factor in postponement of recurrences of nasal polyps.

Adolescent↗
PubMed2005

Comparison of avian cell substrates for propagating subtype C avian metapneumovirus.

Avian metapneumovirus (AMPV) is a respiratory viral pathogen that causes turkey rhinotracheitis (TRT) or swollen head syndrome (SHS) in chickens. AMPV was first isolated in South Africa during the early 1970s and has subsequently spread worldwide during the 1980s to include Europe, Asia, and South America. In 1996, a genetically distinct AMPV subgroup C was isolated in the US following an outbreak of TRT. Vero cells are currently the best available substrate for AMPV propagation but are of non-avian origin. A number of different avian cell substrates have been compared to determine which is the most suitable for the propagation of AMPV to sufficiently high titers. Of the cell substrates tested, primary turkey turbinate and kidney and chicken kidney cells produced titers equal to or greater than Vero cells. Turkey turbinate and kidney epithelial cells that were life-span extended by the ectopic expression of human telomerase catalytic subunit (HTERT) initially displayed AMPV titers comparable to Vero cell controls, but declined in virus production with increased passage in culture. Interestingly, plaques emanating from Vero propagated virus were relatively small and dispersed, when analyzed by immunofluorescent assays (IFA), while both turkey turbinate and kidney cell propagated AMPV produced larger plaques. Even with these differences, there were no changes in the predicted amino acid sequences of the nucleocapsid (N) and phosphoprotein (P) genes of AMPV propagated in either turkey turbinate or Vero host cells. However, the fusion (F) gene showed 11 amino acid differences (98.7% identity) between the two host cell types. These results suggest that AMPV propagated in homologous avian cellular substrates may produce more infectious virus with possibly more effective fusion activity, compared to Vero cell propagation.

Amino Acid Sequence↗
PubMed2002

Chronic insomnia, premenopausal women and sleep disordered breathing: part 2. Comparison of nondrug treatment trials in normal breathing and UARS post menopausal women complaining of chronic insomnia.

OBJECTIVE: The question addressed here is: Can a discrete sleep disordered breathing (SDB) play a role in the insomnia complaint of postmenopausal chronic insomniacs? To respond to the query, two groups of individuals derived from a cohort of postmenopausal chronic insomniacs recruited mostly from the community were enlisted in a treatment protocol. These subjects were all individuals identified with normal breathing (n=68) and all those recognized with Upper Airway Resistance Syndrome (UARS) (n=62) pooled from a cohort of 349 postmenopausal insomniacs. TREATMENT PROTOCOL: The 62 UARS were allocated to either treatment of chronic insomnia by behavioral approaches or treatment of SDB. Based on ENT evaluation, health professionals in charge of patients selected either treatment with nasal CPAP or treatment of nasal turbinates. A stratification correction was performed to obtain a near equal number of both treatment modalities in each of the two subgroups. The 68 individuals with normal breathing were randomly allocated to immediate behavioral treatment of insomnia or delay treatment of insomnia. The delay treatment received a list of 10 sleep hygiene recommendations by mail. METHODOLOGY: Questionnaires, visual analog scales (VAS), Epworth Sleepiness Scale (ESS), clinical interviews, clinical evaluation with oto-laryngologic clinical assessment of a presence/absence of narrow upper airway and location of narrowing. Actigraphy and polysomnography (PSG) with pressure transducer/and nasal cannula system and esophageal manometry. DATA ANALYSES: All recording data were scored blind to patient's condition. RESULTS: Two subjects in the SBD-CPAP treated group (Group B) and two subjects in the delayed treatment group (Group D) dropped out. Total sleep time was improved compared to baseline in all groups, including the delayed treatment group. One group was significantly better (ANOVA, P=.05) with a more important delta score compared to baseline, and this was the behaviorally treated non-SDB. Sleep latency was significantly decreased in the behaviorally treated group (with or without SBD), P=.05, compared to SBD-treated and delayed treatment groups. Sleep latency was, however, improved in all groups. VAS for "quality of sleep" was higher at 6 months in all the groups when compared to "baseline" values. VAS for "daytime fatigue" showed significant differences among the four groups (ANOVA, P=.01); the overall score at the end of treatment was significantly better in the SDB-treated group than the other three groups. SBD was treated either by radio frequency on nasal turbinate or by nasal CPAP. CPAP-treated patients had a lower VAS score than nasal turbinate treatment, but the difference was only a trend. The delta improvement (6-month baseline condition) in "daytime fatigue" of each subgroup was calculated and compared within and between groups. Despite the small number of subjects, the turbinate-treated subgroup was significantly different from Groups B, C and D (ANOVA, P=.05). When a similar comparison was made with the nasal CPAP group, there was only a nonsignificant trend when compared to Groups B, C and D. CONCLUSION: Abnormal breathing during sleep significantly enhanced complaints of daytime fatigue in postmenopausal chronic insomniacs and this complaint improved with SDB treatment. This improvement is significantly better compared to SDB insomniacs treated with a behavioral regimen. Behavioral treatment, however, gave the best response in the non-SDB chronic insomnia group and improved better long sleep latency even in the SDB group. These results suggest the need to find an appropriate treatment for SBD even if mild and to recognize the role of SDB in relation to symptoms seen with chronic insomnia.

Aged↗
PubMed2002

Systematic unciformectomy for a standardized endonasal dacryocystorhinostomy.

PURPOSE: To describe a standardized osteotomy method for endonasal dacryocystorhinostomy (en-DCR) and the results obtained. DESIGN: Prospective nonrandomized, noncomparative, interventional case series study. PARTICIPANTS: One hundred consecutive adult patients (81 females, 19 males) underwent en-DCR performed by the same team of oculoplastic and rhinologic surgeons. METHODS: A standardized procedure was used in all cases. This included endoscopic assessment of the surgical site from the nasal aspect, diaphanoscopy of the common canaliculus, and endonasal osteotomy. Anterior unciformectomy was followed by resection of the lacrimal bone and protected drilling of the maxillary bone of the lacrimal fossa to expose the entire medial aspect of the lacrimal sac. The middle turbinate was preserved whenever atraumatic dissection of the nasal mucosa was possible or when it was resected partially before osteotomy. MAIN OUTCOME MEASURES: Rate of direct localization of the lacrimal fossa, rate of turbinectomy/septoplasty, rate of residual postoperative tearing, rate and nature of complications RESULTS: Transillumination of the common canaliculus was obtained directly in 94% of cases; transillumination, required the opening of an ethmoidal cell in 2%, partial resection of the middle turbinate in 3%, and unciformectomy in 1%. Access to the surgical site required partial resection of the middle turbinate in 21% of cases, but no septoplasty. Osteotomy was initiated in 90% of cases by cleavage of the anterior insertion of the uncinate process, and in 5% by cleavage of the first, overdeveloped ethmoidal cell. The cleavage opened directly to the medial aspect of the lacrimal fossa in these 95 cases. Osteotomy was achieved by drilling alone in only five cases. Perioperative complications were limited to significant bleeding in six cases. Postoperative complications included one case of resolved frontal sinusitis on day 3, and one case of inferior lid hematoma with emphysema. CONCLUSIONS: The authors suggest that anterior resection of the uncinate process is the most important surgical step to expose the medial aspect of the lacrimal fossa during endonasal DCR, whereas partial resection of the middle turbinate can be considered optional.

Adult↗
PubMed2004

Effect of heat treatments on machinability of gold alloy with age-hardenability at intraoral temperature.

OBJECTIVE: This study investigated the effect of heat treatment on the machinability of heat-treated cast gold alloy with age-hardenability at intraoral temperature using a handpiece engine with SiC wheels and an air-turbine handpiece with carbide burs and diamond points. METHODS: Cast gold alloy specimens underwent various heat treatments [As-cast (AC); Solution treatment (ST); High-temperature aging (HA), Intraoral aging (IA)] before machinability testing. The machinability test was conducted at a constant machining force of 0.784N. The three circumferential speeds used for the handpiece engine were 500, 1,000 and 1,500 m/min. The machinability index (M-index) was determined as the amount of metal removed by machining (volume loss, mm(3)). The results were analyzed by ANOVA and Scheffé's test. RESULTS: When an air-turbine handpiece was used, there was no difference in the M-index of the gold alloy among the heat treatments. The air-turbine carbide burs showed significantly (p<0.05) higher M-indexes than the diamond points after any heat treatments. With the SiC wheels, increasing the circumferential speed increased the M-index values for each heat treatment. The specimens heat-treated with AC, HA and IA had similar M-indexes at the lower speeds (500 and 1,000 m/min). The ST specimens exhibited the lowest M-index at the lower speeds. However, at the highest speed (1,500 m/min), there were no significant differences in the M-indexes among the heat treatments except for HA, which showed the highest M-index. CONCLUSION: There was no effect of heat treatment on the machinability of the gold alloy using the air-turbine handpiece. The heat treatments had a small effect on the M-index of the gold alloy machined with a SiC wheel for a handpiece engine.

Body Temperature↗
PubMed1999

Effect of resection velocity and suction ring on corneal flap formation in laser in situ keratomileusis.

PURPOSE: To determine the effects of microkeratome-cutting velocities and the suction ring on corneal flap creation. SETTING: Department of Ophthalmology, College of Medicine, The Catholic University of Korea, Seoul, Korea. METHODS: Procedures were performed under clinical settings in 65 pig eyes. Keratometric diopters (D) were measured before and after application of the suction ring. Corneal thickness was measured before and after resection cutting, and the difference was taken as flap thickness. The microkeratome was initially set at a resection thickness of 160 microns. The blade oscillation (turbine velocity) was set at 30, 35, and 42 psi. The translational velocity was arbitrarily divided into high (1 to 2 seconds), moderate (3 to 5 seconds), and low (6 seconds or more). Data were analyzed by varying the velocities consecutively. Photographs of the cut surface were acquired by scanning electron microscopy to evaluate resection morphology by comparison. RESULTS: Mean refractive powers were 39.94 D +/- 0.66 (SD) and 39.69 +/- 0.98 D before and after application of the suction ring, respectively; however, no significant difference was observed (P = .216). Lower surgeon translational velocity resulted in a significantly thicker corneal flap in 8 of the 9 paired comparisons (P < .05). Higher turbine velocity resulted in a significantly thicker corneal flap in 7 of the 9 paired comparisons (P < .05). The cut surface was smoother at higher turbine and lower translational velocity. The initial cut margin was steeper at higher translational velocity. CONCLUSIONS: The increase in intraocular pressure induced by the suction ring had no significant effect on keratometric power. At higher turbine and lower translational velocities, the corneal flap was thicker and the cut surface smoother. Higher translational velocities made the initial cut margin steeper.

Animals↗
PubMed1997

Evaluation of a new device for sterilizing dental high-speed handpieces.

Dental high-speed turbines and handpieces can take up and expel microorganisms during operation and thus need regular sterilization. This study established a method for validating devices used to sterilize high-speed turbines and handpieces. The air and water channels and turbine chambers were contaminated with suspensions of Streptococcus salivarius or endospores of Bacillus stearothermophilus. The effect of flushing and/or autoclaving performed by a new device combining both procedures was evaluated by counting the number of viable bacteria recovered from these devices. Further, the effect on clinically used handpieces was evaluated. In an initial experiment, the device partially reduced S. salivarius, and the endospores survived. In a second experiment, a 5 to 6 log reduction of S. salivarius in air and water channels was obtained. No growth was observed in clinically used high-speed handpieces, and both S. salivarius and endospores were eliminated from the turbine chambers. Thus, the method of validation proved capable of discriminating between different levels of bacterial reduction.

Air↗
PubMed2000

Effects of mixing on fed-batch fermentation of L-ornithine.

The effects of mixing on L-ornithine fermentation were studied using an L-arginine auxotrophic mutant of Brevibacterium ketoglutamicum ATCC 21092. Three different modes of fed-batch culture using two different impeller types were studied in a 7 l fermentor. The first two modes of fed-batch culture were carried out in a fermentor equipped with six-flat-blade disk-turbine impellers with top and bottom feeding. The third mode of fed batch culture was carried out using pitched-six-flat-blade disk-turbine impellers with top feeding. The titre of L-ornithine increased up to 1.8 fold with bottom-feeding or when the pitched-six-flat-blade disk-turbine impellers were used compared to when the six-flat-blade disk-turbine impellers with top-feeding were used. It was observed that the mixing time of the limiting nutrients varied significantly depending on both the direction of feeding and the impeller type. Since the profiles of the specific rates of CO2 evolution, oxygen and glucose uptakes were very similar for the three culture modes, it could be reasonably assumed that the microorganism exhibited similar growth rates for each mode used. However, different amino acid producing activities were observed in the three culture modes. From these results it is concluded that the productivity of L-ornithine fermentation is significantly improved by shortening the mixing time of the limiting nutrient in the fermentor.

Journal Article↗
PubMed2005

Reducing CO2 emissions and energy consumption of heat-integrated distillation systems.

Distillation systems are energy and power intensive processes and contribute significantly to the greenhouse gases emissions (e.g. carbon dioxide). Reducing CO2 emissions is an absolute necessity and expensive challenge to the chemical process industries in orderto meetthe environmental targets as agreed in the Kyoto Protocol. A simple model for the calculation of CO2 emissions from heat-integrated distillation systems is introduced, considering typical process industry utility devices such as boilers, furnaces, and turbines. Furnaces and turbines consume large quantities of fuels to provide electricity and process heats. As a result, they produce considerable amounts of CO2 gas to the atmosphere. Boilers are necessary to supply steam for heating purposes; besides, they are also significant emissions contributors. The model is used in an optimization-based approach to optimize the process conditions of an existing crude oil atmospheric tower in order to reduce its CO2 emissions and energy demands. It is also applied to generate design options to reduce the emissions from a novel internally heat-integrated distillation column (HIDiC). A gas turbine can be integrated with these distillation systems for larger emissions reduction and further energy savings. Results show that existing crude oil installations can save up to 21% in energy and 22% in emissions, when the process conditions are optimized. Additionally, by integrating a gas turbine, the total emissions can be reduced further by 48%. Internal heat-integrated columns can be a good alternative to conventional heat pump and other energy intensive close boiling mixtures separations. Energy savings can reach up to 100% with respect to reboiler heat requirements. Emissions of these configurations are cut down by up to 83%, compared to conventional units, and by 36%, with respect to heat pump alternatives. Importantly, cost savings and more profit are gained in parallel to emissions minimization.

Air Pollution↗
PubMed1999

Expression of histidine decarboxylase messenger RNA and histamine N-methyltransferase messenger RNA in nasal allergy.

BACKGROUND: Histamine is an important chemical mediator in allergic rhinitis. Histamine is synthesized by L-histidine, catalysed by L-histidine decarboxylase (HDC) and metabolized mainly by histamine N-methyltransferase (HMT). The patients with allergic rhinitis may have altered histamine metabolism in the nasal tissue. OBJECTIVE: The objective was to compare the expression of HDC mRNA and HMT mRNA in nasal mucosa with normal individuals and patients with allergic rhinitis. METHODS: We extracted RNA from scrapings of inferior turbinate mucosa of 11 patients with allergic rhinitis and from 11 normal subjects and from surgically dissected inferior turbinate mucosa of 11 patients. HDC, HMT and beta-actin mRNA were amplified by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The mean +/- SD of HDC/beta-actin ratios were 0.58 +/- 0.28 for the scrapings of normal subjects, 0.93 +/- 0.38 for the scrapings of the patients with allergic rhinitis and 1.41 +/- 0.26 for the inferior turbinates of the patients with allergic rhinitis. The mean +/- SD of HMT/beta-actin ratios were 1.66 +/- 0.27 for the scrapings of normal subjects, 0.93 +/- 0.20 for the scrapings of the patients with allergic rhinitis and 0.65 +/- 0.28 for the inferior turbinates of the patients with allergic rhinitis. The differences among the three groups were statistically significant. CONCLUSIONS: Increased HDC mRNA expression and decreased HMT mRNA expression may be playing some role in the hyperresponsiveness of patients with allergic rhinitis.

Actins↗
PubMed2001

Study and application of a mathematical model for the provisional assessment of areas and nasal resistance, obtained using acoustic rhinometry and active anterior rhinomanometry.

Nasal resistance (NR) depends on the geometrical features and tortuosity of the nasal airway and on the air flow. Knowing the longitudinal distribution of cross-sectional areas (CSAs) in the nasal cavity (which can be obtained using acoustic rhinometry) and the laminar nasal resistance (obtainable by processing the rhinomanometric results), it is possible to calculate, utilizing a mathematical model elaborated on the basis of fluid dynamics, the differential nasal resistance (NRdiff) and the cumulative nasal resistance (NRcum), thus localizing the position at which the highest resistance is concentrated and the related longitudinal distribution. Using a mathematical model, we integrated the sigmoid curves DeltaP/Q of rhinomanometry with the cross-sectional areas obtained using acoustic rhinometry, thus obtaining the normal distribution of differential and cumulative nasal resistances. Afterwards, we empirically reduced the cross-sectional areas corresponding to the head, body, tail and the whole inferior turbinate, recalculating the differential and cumulative nasal resistance distribution curves. The results show that reduction of up to 50% of cross-sectional areas does not substantially affect the resistivity role of the nasal valve, while greater reductions move the highest resistivity point to an area at the junction of the body and the head of the inferior turbinate. The study of the differential nasal resistance trend curves as a function of the reduction of cross-sectional areas shows that the resistance variation of the body and the whole inferior turbinate prevail with reductions of up to 40%, while the variation of cross-sectional areas of the body bordering the inferior turbinate head is predominant with higher reductions. The cross-sectional areas of the nasal airway cavity with highest resistivity are mainly located in an anterior position, where the differential nasal resistances are higher, but there are substantial variations produced by reducing the cross-sectional area of the posterior nasal airway. A similar model can produce provisional values for the results obtainable with functional nasal surgery.

Acoustics↗