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J Tang

Publications and source records attributed to J Tang.

At least 55 records · Page 3Linked to original sources
PubMed2001

Differences between subcultures of the Mesorhizobium loti type strain from different culture collections.

Because of differences in the reported 16S rRNA gene sequence of the Mesorhizobium loti type strain available from different culture collections, we collected different subcultures of this strain and compared them by 16S rDNA sequencing, SDS-PAGE of whole-cell protein extracts and RAPD-PCR. Our results indicate that the 16S rDNA sequence differences can be explained by the presence of two different organisms in one of the subcultures. In addition, even for subcultures of the type strain that had identical 16S rDNA sequences, small differences could be observed in the protein profiles and in the RAPD-PCR patterns. These latter observations indicate that maintenance procedures necessary for long-term preservation by freeze-drying can cause subcultures of the same original strain to undergo changes, effectively leading to different fingerprints even though 16S rDNA sequences remain identical.

DNA Fingerprinting↗
PubMed2001

Lower BMI cut-off value to define obesity in Hong Kong Chinese: an analysis based on body fat assessment by bioelectrical impedance.

There is increasing evidence suggesting that the cut-off values for defining obesity used in the Western countries cannot be readily applied to Asians, who often have smaller body frames than Caucasians. We examined the BMI and body fat (BF) as measured by bioelectrical impedance in 5153 Hong Kong Chinese subjects. We aimed to assess the optimal BMI reflecting obesity as defined by abnormal BF in Hong Kong Chinese. Receiver operating characteristic curve (ROC) analysis was used to assess the optimal BMI predicting BF at different levels. The mean age and SD of the 5153 subjects (3734 women and 1419 men) was 51.5 (SD 16.3) years (range: 18.0-89.5 years, median: 50.7 years). Age-adjusted partial correlation (r) between BMI and BF in women and men were 0.899 (P < 0.001) and 0.818 (P < 0.001) respectively. Using ROC analysis, the BMI corresponding to the conventional upper limit of normal BF was 22.5-23.1 kg/m(2), and the BMI corresponding to the 90 percentiles of BF was 25.4-26.1 kg/m(2). Despite similar body fat contents, the BMI cut-off value used to define obesity in Hong Kong Chinese should be lower as compared to Caucasians. We suggest a BMI of 23 kg/m(2) and 26 kg/m(2) as the cut-off values to define overweight and obesity respectively in Hong Kong Chinese.

Absorptiometry, Photon↗
PubMed2001

Helper virus-free HSV-1 vectors packaged both in the presence of VSV G protein and in the absence of HSV-1 glycoprotein B support gene transfer into neurons in the rat striatum.

Herpes simplex virus (HSV-1) vectors have potential for gene transfer into quiescent cells, but the gene transfer process could be more efficient. In other vector systems, both the titers and the efficiency of gene transfer have been enhanced by pseudotyping the vector particles with vesicular stomatitis virus (VSV) G protein. In this report, we pseudotyped helper virus-free HSV-1 plasmid vectors with VSV G protein. Packaging was performed in the presence of both VSV G protein and a deletion in an essential HSV-1 glycoprotein, gB. The resulting vector stocks supported gene transfer into both fibroblast and neuronal cell lines. VSV G protein was required for gene transfer because preincubation of these vector stocks with antibodies directed against either VSV G protein or VSV reduced the titer to undetectable levels. Although the titers were lower than those obtained using the unmodified vector system, the titers were not increased by use of chimeric proteins that contain the extracellular domain of VSV G protein and the transmembrane and/or cytoplasmic domains of specific HSV-1 glycoproteins. Also, the titers were not increased by performing the packaging in the presence of deletions in multiple HSV-1 glycoproteins. Nonetheless, pHSVlac pseudotyped with VSV G protein supported gene transfer into striatal neurons in the rat brain. Thus, HSV-1 vectors pseudotyped with VSV G protein may be useful for specific gene transfer studies.

Animals↗
PubMed2001

Effects of repeated oral postnatal exposure to chlorpyrifos on open-field behavior in juvenile rats.

Organophosphorus (OP) insecticides have the potential to cause behavioral effects in children. This study was designed to determine if repeated oral exposure of preweanling rats to chlorpyrifos would produce behavioral changes at both pre- and postweanling ages. Treatment occurred every second day beginning on post-natal day (PND) 1, and continued through PND 21. The rats received one of the following regimens: a low-dosage (3 mg/kg) from PND 1-21; a medium dosage (mg/kg from PND 1-5, and then 6 mg/kg from PND 7-21; or a high-dosage schedule of 3 mg/kg on PND 1-5, then 6 mg/kg from PND 7-13, and 12 mg/kg from PND 15-21. There were no differences in body weights among the control-, low-, and medium-dosage groups but the high-dosage group had significantly lower body weights on PND 13-21. An open field was used to measure locomotor activity on PND 10, 12, 14, 16, 18, 20, 25, and 30. There were no differences in locomotor activity levels or treatment effects between males and females. On PND 10, 12, 14, 16, 18, and 20 there was no effect on locomotor activity with any dosage. On days 25 and 30, locomotor activity was significantly decreased with the medium- and high-dosage groups. Brain cholinesterase (ChE) inhibition was about 25-38% on PND 25 and 14-34% on PND 30. On PND 25 but not 30, lung and diaphragm ChE and serum butyrylcholinesterase (BChE), with the high-dosage animals, and heart ChE with the medium- and high-dosage groups were significantly inhibited. There was no significant inhibition of skeletal muscle ChE or serum acetylcholinesterase (AChE) on PND 25 and 30. These data suggest that early postnatal chlorpyrifos exposures will depress locomotor activity in juvenile rats, with the effects most pronounced after brain ChE activity has substantially recovered.

Acetylcholinesterase↗
PubMed2001

Fast-track office-based anesthesia: a comparison of propofol versus desflurane with antiemetic prophylaxis in spontaneously breathing patients.

IMPLICATIONS: Compared to propofol, maintenance of anesthesia with desflurane provided significantly better intraoperative conditions during office-based surgery. In addition, desflurane with routine antiemetic prophylaxis was associated with a faster early recovery and similar incidence of postoperative side effects.

Ambulatory Surgical Procedures↗
PubMed2001

Propacetamol versus ketorolac for treatment of acute postoperative pain after total hip or knee replacement.

We assessed the analgesic efficacy of IV propacetamol and ketorolac in a double-blinded, placebo-controlled study involving patients undergoing total hip or knee replacement procedures. On the first morning after major joint replacement surgery, 164 patients experiencing moderate-to-severe pain were randomly assigned to receive an IV infusion of propacetamol (2 g), ketorolac (15 or 30 mg), or placebo (saline). Patient-controlled analgesia with morphine was made available as a "rescue" analgesic on patient's request during the 6-h postdosing evaluation period. The median time to onset of analgesia with propacetamol (8 [95% confidence interval 6,10] min) was shorter than ketorolac 15 mg (14 [7,16] min), and placebo (16 [8; not estimable] min) although the differences did not reach statistical significance. However, compared with ketorolac 30 mg, propacetamol had a shorter duration of analgesia (3.5 [2;5.4] vs 6 [3.3; not estimable] h). Analysis of pain intensity and pain relief scores demonstrated that propacetamol produced a significantly greater improvement in pain relief than saline from 45 min until 5 h after the injection. Propacetamol was not significantly different from ketorolac 15 mg and 30 mg with respect to the main analgesic efficacy variables during the 6-h assessment period. The most frequently reported adverse event with propacetamol was injection site pain (28% vs 19% for ketorolac 15 mg, 29% for ketorolac 30 mg, and 10% for placebo, respectively). In conclusion, propacetamol (2 g IV) possesses a similar analgesic efficacy to ketorolac (15 or 30 mg IV) after total hip or knee replacement surgery.

Acetaminophen↗
PubMed2001

The effect of timing of dolasetron administration on its efficacy as a prophylactic antiemetic in the ambulatory setting.

UNLABELLED: Dolasetron (12.5 mg IV) is effective in both preventing and treating postoperative nausea and vomiting (PONV) after ambulatory surgery. However, the optimal timing of dolasetron administration and its effect on the patient's quality of life after discharge have not been established. One-hundred-five healthy, consenting women undergoing gynecologic laparoscopic procedures with a standardized general anesthetic technique were enrolled in this randomized, double-blinded study. Group 1 received dolasetron 12.5 mg IV 10-15 min before the induction of anesthesia; Group 2 received dolasetron 12.5 mg IV at the end of the laparoscopy (79 +/- 48 min later than Group 1); and Group 3 received dolasetron 12.5 mg IV at the end of anesthesia (93 +/- 52 min later than Group 1). The incidence of PONV, complete responses (defined as no emetic episodes and no rescue medication within the 24-h period after anesthesia), recovery profiles, and patient satisfaction were recorded. In the postanesthesia care unit and during the 24-h follow-up period, the incidence of nausea and vomiting, as well as the need for rescue antiemetics, did not differ significantly among the three groups. The percentages of patients with complete responses to the study drug within the first postoperative 24 h were also similar in all three groups (55%, 59%, and 52% for Groups 1, 2, and 3, respectively). The early and intermediate recovery profiles, including resumption of a normal diet and patient satisfaction with the control of PONV, were not different among the three study groups. Dolasetron 12.5 mg IV administered before the induction of anesthesia is as effective as dolasetron given at the end of laparoscopy or at the end of anesthesia in preventing PONV after outpatient laparoscopy. IMPLICATIONS: The timing of dolasetron administration appears to have little effect on its efficacy when administered as a prophylactic antiemetic in the ambulatory setting.

Adult↗
PubMed2001

The recovery of cognitive function after general anesthesia in elderly patients: a comparison of desflurane and sevoflurane.

UNLABELLED: We evaluated the cognitive recovery profiles in elderly patients after general anesthesia with desflurane or sevoflurane. After IRB approval, 70 ASA physical status I-III consenting elderly patients (> or =65 yr old) undergoing total knee or hip replacement procedures were randomly assigned to one of two general anesthetic groups. Propofol and fentanyl were administered for induction of anesthesia, followed by either desflurane 2%-4% or sevoflurane 1%-1.5% with nitrous oxide 65% in oxygen. The desflurane (2.5 +/- 0.6 MAC. h) and sevoflurane (2.7 +/- 0.5 MAC. h) concentrations were adjusted to maintain comparable depths of hypnosis using the electroencephalogram bispectral index monitor. The Mini-Mental State (MMS) test was used to assess cognitive function preoperatively and postoperatively at 1, 3, 6, and 24-h intervals. The use of desflurane was associated with a more rapid emergence from anesthesia (6.3 +/- 2.4 min versus 8.0 +/- 2.8 min) and a shorter length of stay in the postanesthesia care unit (213 +/- 66 min versus 241 +/- 87 min). However, there were no significant differences between the Desflurane and the Sevoflurane groups when the MMS scores were compared preoperatively, and postoperatively at 1, 3, 6, and 24 h. Compared with the preoperative (baseline) MMS scores, the values were significantly decreased at 1 h postoperatively (27.8 +/- 1.7 versus 29.5 +/- 0.5 in the Desflurane group, and 27.4 +/- 1.7 versus 29.2 +/- 1.0 in the Sevoflurane group, respectively). However, the MMS scores returned to preoperative baseline levels within 6 h after surgery. At 1 h and 3 h after surgery, 51% and 11% (versus 57% and 9%) of patients in the Desflurane (versus Sevoflurane) Group experienced cognitive impairment. In conclusion, desflurane is associated with a faster early recovery than sevoflurane after general anesthesia in elderly patients. However, recovery of cognitive function was similar after desflurane and sevoflurane-based anesthesia. IMPLICATIONS: Desflurane was associated with a faster early recovery than sevoflurane after general anesthesia in elderly patients. However, recovery of cognitive function was similar with both volatile anesthetics.

Aged↗
PubMed2001

Polymorphisms in HLA class I genes associated with both favorable prognosis of human immunodeficiency virus (HIV) type 1 infection and positive cytotoxic T-lymphocyte responses to ALVAC-HIV recombinant canarypox vaccines.

Carriers of certain human leukocyte antigen class I alleles show favorable prognosis of human immunodeficiency virus type 1 (HIV-1) infection, presumably due to effective CD8(+) cytotoxic T-lymphocyte responses, but close relationships between class I variants mediating such responses to natural and to vaccine HIV-1 antigen have not been established. During 6 to 30 months of administration and follow-up in trials of ALVAC-HIV recombinant canarypox vaccines, cells from 42% of 291 HIV-1-negative vaccinated subjects typed at class I loci responded to an HIV-1 protein in a lytic bulk CD8(+) cytotoxic T-lymphocyte assay. By 2 weeks after the second dose, higher proportions of vaccinees carrying one of two alleles consistently associated with slower progression of natural HIV-1 infection reacted at least once: B*27 carriers reacted to Gag (64%; odds ratio [OR] = 10.3, P = 0.001) and Env (36%; OR = 4.6, P = 0.04), and B*57 carriers reacted to Env (44%; OR = 6.6, P < 0.05). By 2 weeks after the third or fourth dose, B*27 carriers had responded (two or more reactions) to Gag (33%; OR = 4.4, P < 0.05) and B*57 carriers had responded to both Gag (39%; OR = 5.3, P = 0.013) and Env (39%; OR = 9.5, P = 0.002). Homozygosity at class I loci, although conferring an unfavorable prognosis following natural infection, showed no such disadvantage for vaccine response. Individual class I alleles have not previously demonstrated such clear and consistent relationship with both the clinical course of an infection and cellular immunity to a vaccine against the infectious agent. This proof of principle that class I an alleles modulate both processes has implications for development of HIV-1 and presumably other vaccines.

AIDS Vaccines↗
PubMed2001

The regulatory role of DR4 in a spontaneous diabetes DQ8 transgenic model.

MHC class II molecules are critical determinants of genetic susceptibility to human type 1 diabetes. In patients, the most common haplotype contains the DRA1*0101-DRB1*0401 (DR4) and DQA1*0301-DQB1*0302 (DQ8) loci. To assess directly the relative roles of HLA-DQ8 and DR4 for diabetes development in vivo, we generated C57BL/6 transgenic mice that lack endogenous mouse MHC class II molecules but express HLA-DQ8 and/or DR4. Neither HLA-DQ nor HLA-DR transgenic mice developed insulitis or spontaneous diabetes. However, when they were crossed to transgenic mice (C57BL/6) expressing the B7.1 costimulatory molecules on pancreatic beta cells that do not normally develop diabetes, T cells from these double transgenic mice were no longer tolerant to islet autoantigens. The majority of DQ8/RIP-B7 mice developed spontaneous diabetes, whereas only 25% of DR4/RIP-B7 mice did so. Interestingly, when DQ8 and DR4 were coexpressed (DQ8DR4/RIP-B7), only 23% of these mice developed diabetes, an incidence indistinguishable from the DR4/RIP-B7 mice. T cells from both DR4/RIP-B7 and DQ8DR4/RIP-B7 mice, unlike those from DQ8/RIP-B7 mice, exhibited a Th2-like phenotype. Thus, the expression of DR4 appeared to downregulate DQ8-restricted autoreactive T cells in DQ8DR4/RIP-B7 mice. Our data suggest that although both DQ8 and DR4 can promote spontaneous diabetes in mice with a non-autoimmune-prone genetic background, the diabetogenic effect of the DQ8 allele is much greater, whereas DR4 expression downregulates the diabetogenic effect of DQ8, perhaps by enhancing Th2-like immune responses.

Animals↗
PubMed2001

A comparative study on the viscoelasticity and morphology of polyaniline films galvanostatically grown on bare and 4-aminothiophenol-modified gold electrodes using an electrochemical quartz crystal impedance system and SEM.

The equivalent-circuit parameters of the 9-MHz piezoelectric quartz crystal (PQC) resonance were measured in situ during the galvanostatic polymerization of aniline on 4-aminothiophenol(4-ATP)-modified and bare Au electrodes for ca. 2000 s, respectively. Two polymerization media, 0.100 mol L-1 aniline in 1.0 mol L-1 H2SO4 and in 2.0 mol L-1 HClO4 aqueous solutions, and two values of the current density, 12 and 36 microA cm-2, were used. At identical levels of the resonant frequency shifts in the solutions, obviously greater increases in the motional resistance (R1) were found after aniline polymerization on bare Au electrodes, though the absolute values of delta f0/delta R1 were all large; also, the resonant frequency shifts in air (delta f0g) were considerably smaller for PANI films grown on bare Au electrodes. It is thus concluded that, under identical polymerization conditions, (1) the PANI film grown on a bare gold electrode is rougher, less compact, and can entrap solution more notably; (2) the deposition efficiency of PANI is higher on a 4-ATP-modified Au electrode, owing to a significantly greater observed "dry" frequency shift, and thus a greater "net" mass value of the polyaniline backbone. SEM observations have confirmed that PANI films on 4-ATP-modified Au electrodes were smoother and more compact than those grown on bare Au ones under identical polymerization conditions. In addition, a technique of simultaneous measurements of the electroacoustic admittance of the PQC resonance and the electrochemical impedance was used to monitor the adsorption of 4-ATP onto a PQC gold electrode.

Journal Article↗
PubMed2001

Abnormalities of retinal metabolism in diabetes and experimental galactosemia. VII. Effect of long-term administration of antioxidants on the development of retinopathy.

Antioxidants were administered to diabetic rats and experimentally galactosemic rats to evaluate the ability of these agents to inhibit the development of diabetic retinopathy. Alloxan diabetic rats and nondiabetic rats that were fed 30% galactose randomly received standard diets or the diets supplemented with ascorbic acid and alpha-tocopherol (vitamins C+E diet) or a more comprehensive mixture of antioxidants (multi-antioxidant diet), including Trolox, alpha-tocopherol, N-acetyl cysteine, ascorbic acid, beta-carotene, and selenium. Diabetes or galactose feeding of at least 12 months resulted in pericyte loss, acellular capillaries, and basement membrane thickening. Compared with diabetic controls, the development of acellular capillaries was inhibited by 50% (P < 0.05) in diabetic rats that received supplemental vitamins C+E, and the number of pericyte ghosts tended to be reduced. The vitamins C+E supplement had no beneficial effect in galactosemic rats, but these rats consumed only approximately half as much of the antioxidants as the diabetic rats. The multi-antioxidant diet significantly inhibited ( approximately 55-65%) formation of both pericyte ghosts and acellular capillaries in diabetic rats and galactosemic rats (P < 0.05 vs. controls), without affecting the severity of hyperglycemia. Parameters of retinal oxidative stress, protein kinase C activity, and nitric oxides remained elevated for at least 1 year of hyperglycemia, and these abnormalities were normalized by multi-antioxidant therapy. Thus, long-term administration of antioxidants can inhibit the development of the early stages of diabetic retinopathy, and the mechanism by which this action occurs warrants further investigation. Supplementation with antioxidants can offer an achievable and inexpensive adjunct therapy to help inhibit the development of retinopathy in diabetes.

Acetylcysteine↗
PubMed2001

Particle size analysis as a tool for performance measurements in high rate effluent filtration.

In the Netherlands almost all wastewater treatment plants have been redesigned and adapted in order to remove nitrogen, phosphorus and suspended solids to a very low level. The improved effluent quality leads to a growing interest in the reuse of effluent of the modernised wastewater treatment plants. This again results in investigations on filtration techniques as deep bed filtration and membrane filtration. At the wastewater treatment plant Ede research was done on deep bed filtration in order to develop relations between particle removal and filter performance and to explore ways of optimization. The results of the experiments are rather typical for effluent of modern Dutch wastewater treatment plants. The very low concentrations of suspended solids and precipitable substances result in poor flocculating properties. From turbidity measurements it may be concluded that the best results were obtained with a dosage of flocculant. However, the particle size measurements indicated the opposite. Suspended solids calculations, based on the particle volume distributions, showed a better removal without a dosage of flocculant. From this it is concluded that a dosage of coagulant (Fe3+ or Al3+) has an adverse effect on the removal efficiencies even at low dosages (1 mg/l).

Conservation of Natural Resources↗
PubMed2001

Metabolism of chlorpyrifos by human cytochrome P450 isoforms and human, mouse, and rat liver microsomes.

One of the factors determining the toxicity of chlorpyrifos (CPS), an organophosphorus (OP) insecticide, is its biotransformation. CPS can be activated by cytochrome P450 (CYP) through a desulfuration reaction to form chlorpyrifos-oxon (CPO), a potent anticholinesterase. CPS can also be detoxified by CYP through a dearylation reaction. Using pooled human liver microsomes (HLM), a K(m(app)) of 30.2 microM and V(max(app)) of 0.4 nmol/min/mg of protein was obtained for desulfuration, and a K(m(app)) of 14.2 microM and a V(max(app)) of 0.7 nmol/min/mg of protein was obtained for dearylation. These activities are lower than those obtained from rat liver microsomes. Gender differences in humans were also observed with female HLM possessing greater activity than male HLM. Use of human CYP isoforms expressed in human lymphoblastoma cells demonstrated that CYP1A2, 2B6, 2C9*1, 2C19, and 3A4 are involved in CPS metabolism. CYP2B6 has the highest desulfuration activity, whereas dearylation activity is highest for 2C19. CYP3A4 has high activity for both dearylation and desulfuration. The use of phenotyped individual HLM demonstrated that predictions of metabolic activation and/or detoxication could be made based on relative amounts of CYP2B6, 2C19, and 3A4 in the microsomes. Thus, individuals with high CYP2C19 but low 3A4 and 2B6 are more active in dearylation than in desulfuration. Similarly, individuals possessing high levels of CYP2B6 and 3A4 have the greatest potential to form the activation product. These differences between individuals suggest that differential sensitivities to CPS may exist in the human population.

Animals↗
PubMed2001

Body mass index profile in Hong Kong Chinese adults.

INTRODUCTION: Obesity has now become an epidemic with increasing prevalence in most parts of the world. However, information on the problem of obesity in Asians is limited. SUBJECTS AND METHODS: From April 1996 to August 1997, 17,121 Chinese adult subjects from the community of Hong Kong presented themselves voluntarily at the United Christian Nethersole Community Health Service Centers for primary health care check-up. Demographic data including height and weight were documented. Their body mass indexes (BMI) were measured. The prevalence rates of overweight and obese subjects were calculated according to the 1995 World Health Organization criteria. RESULTS: There were 4781 (27.9%) men and 12,340 (72.1%) women. The mean age (+/- SD) was 51.3 +/- 16.0 years (range 20 to 96 years, median 49.8 years). Of the 17,121 subjects, 4939 (28.85%) were overweight and 656 (3.83%) were obese. Based on the 1997 Hong Kong Census statistics of the overall Hong Kong population data, the age-standardised prevalence rates of overweight and obese subjects were 30.52% and 3.19% in men and 22.14% and 3.35% in women, respectively. Of the 10,937 subjects of working age (20 to 65 years), the prevalence rates of overweight and obese subjects were 28.98% and 3.55%, respectively. Of the 6648 subjects aged > or = 60 years, the prevalence rates of overweight and obese subjects were 36.31% and 4.81%, respectively. CONCLUSIONS: In Hong Kong, the age-standardised prevalence rate of overweight and obese subjects were 30.5% and 3.2% in men and 22.1% and 3.4% in women, respectively. This information provides some useful estimations of the extent of an important public health problem, obesity, in Hong Kong.

Adult↗
PubMed2001

[Continuous measurement of baseline atmospheric carbon monoxide in western China].

In-situ custom-designed gas chromatography(GC)-HgO system was established for the continuous measurement of atmospheric CO at Waliguan Baseline Station(36 degrees 17' N, 100 degrees 54' E, 3816 m asl) in western China. The system's assembling, testing, running and calibration indicated that the chromatographic method has stable baseline and high separation efficiency, as well as reliable detection method. This system adopted high automatic operating techniques and followed strict quality control. It is up to the standard of WMO's baseline watch on global atmosphere. According to the flask sampling results of in-situ CO variation at Waliguan, CO standards in clean dry air under international comparison were used to determine the adjustable working standard curves, so as to calculate the ambient CO mixing ratios based on peak height. This system's detection limit for CO is around 1 x 10(-9) (V/V), the precision is below 0.1% and accuracy in +/- 0.05%, it can provide continuous and accurate surface CO mixing ratios in baseline areas of China.

Air↗
PubMed2001

Tracheal-innominate artery fistula caused by the endotracheal tube tip: case report and investigation of a fatal complication of prolonged intubation.

CASE REPORT: A patient with extensive burns was intubated with an 8.0 mm internal diameter endotracheal tube (ETT) equipped with a subglottic suction port (Mallinckrodt HiLo Evac). The ETT was secured to a left upper molar with wire sutures throughout the hospitalization course to ensure airway stability. On the 40th day of intubation, the patient exsanguinated and died from a tracheo-innominate artery fistula. Postmortem examination revealed a 1 cm lesion of the left anterior tracheal wall at the position of the ETT tip. The prolonged stationary position of the ETT was considered the primary factor responsible for the fistula. Yet tracheo-innominate artery fistula normally is associated with high cuff pressures rather than with the tube tip. The special ETT construction required for the subglottic suction feature was suspected to have increased tube rigidity and may have played a contributory role. METHODS: The rigidity of the Mallinckrodt HiLo Evac was measured with a mechanical model and compared to 5 other commercially-available ETTs. Rigidity was expressed as the force generated by the ETT tip when the tube curvature was altered by 5 cm and 10 cm of flexion from its resting position. RESULTS: The mean force exerted by the Mallinckrodt HiLo Evac was 10.1 +/- 2.8 g at 5 cm of flexion and 17.7 +/- 5.1 g at 10 cm of flexion. This was significantly greater than all other ETT brands tested (by one-way analysis of variance and Student-Newman-Kuels test, p < 0.05). CONCLUSION: This case of fatal tracheo-innominate artery fistula formation associated with an ETT tip was unusual because of the extended duration of endotracheal intubation and the complexity of the patient's airway management problems. Our data suggest that the higher rigidity of the HiLo Evac ETT may have contributed to fistula development at the tube tip. However, we do not believe that the higher rigidity of the HiLo Evac ETT necessarily poses any greater risk than other ETTs under normal circumstances, in which the tube tip is not fixed in a stationary position for an extended period.

Adult↗