Evaluating the hearing screening effectiveness of active noise cancellation technology among young adults: A pilot study

BACKGROUND

The population of young adults who are hearing impaired increases yearly, and a device that enables convenient hearing screening could help monitor their hearing. However, background noise is a critical issue that limits the capabilities of such a device. Therefore, this study evaluated the effectiveness of commercial active noise cancellation (ANC) headphones for hearing screening applications in the presence of background noise. In particular, six confounders were used for a comprehensive evaluation.

METHODS

We enrolled 12 young adults (a total of 23 ears with normal hearing) to participate in this study. A cross-sectional self-controlled study was conducted to explore the effectiveness of hearing screening in the presence of background noise, with a total of 240 test conditions (=3 ANC models × 2 ANC function statuses × 2 noise types × 5 noise levels × 4 frequencies) for each test ear. Subsequently, a linear regression model was used to prove the effectiveness of ANC headphones for hearing screening applications in the presence of background noise with six confounders.

RESULTS

The experimental results showed that, on average, the ANC function of headphones can improve the effectiveness of hearing screening tasks in the presence of background noise. Specifically, the statistical analysis showed that the ANC function enabled a significant 10% improvement ( p < 0.001) compared with no ANC function.

CONCLUSION

This study confirmed the effectiveness of ANC headphones for young adult hearing screening applications in the presence of background noise. Furthermore, the statistical results confirmed that as confounding variables, noise type, noise level, hearing screening frequency, ANC headphone model, and sex all affect the effectiveness of the ANC function. These findings suggest that ANC is a potential means of helping users obtain high-accuracy hearing screening results in the presence of background noise. Moreover, we present possible directions of development for ANC headphones in future studies.

Objective Signal Analysis for Investigating Feasibility of Active Noise Cancellation in Hearing Screening

With the development of active noise cancellation (ANC) technology, ANC has been used to mitigate the effects of environmental noise on audiometric results. However, objective evaluation methods supporting the accuracy of audiometry for ANC exposure to different levels of noise have not been reported. Accordingly, the audio characteristics of three different ANC headphone models were quantified under different noise conditions and the feasibility of ANC in noisy environments was investigated. Steady (pink noise) and non-steady noise (cafeteria babble noise) were used to simulate noisy environments. We compared the integrity of pure-tone signals obtained from three different ANC headphone models after processing under different noise scenarios and analyzed the degree of ANC signal correlation based on the Pearson correlation coefficient compared to pure-tone signals in quiet. The objective signal correlation results were compared with audiometric screening results to confirm the correspondence. Results revealed that ANC helped mitigate the effects of environmental noise on the measured signal and the combined ANC headset model retained the highest signal integrity. The degree of signal correlation was used as a confidence indicator for the accuracy of hearing screening in noise results. It was found that the ANC technique can be further improved for more complex noisy environments.

[Analysis of CT features of 15 children with 2019 novel coronavirus infection]

Objective: To explore imaging characteristics of children with 2019 novel coronavirus (2019-nCoV) infection. Methods: A retrospective analysis was performed on clinical data and chest CT images of 15 children diagnosed with 2019-nCoV infection. They were admitted to the Third People's Hospital of Shenzhen from January 16 to February 6, 2020. The distribution and morphology of pulmonary lesions on chest CT images were analyzed. Results: Among the 15 children, 5 were males and 10 females, aged from 4 to 14 years. Five of the 15 children were febrile and 10 were asymptomatic on the first visit. The first nasal or pharyngeal swab samples in all the 15 cases were positive for 2019-nCoV nucleic acid. For their first chest CT images, 6 patients had no lesions, while 9 patients had pulmonary inflammatory lesions. Seven cases had small nodular ground glass opacities and 2 cases had speckled ground glass opacities. After 3 to 5 days of treatment, 2019-nCoV nucleic acid in a second respiratory sample turned negative in 6 cases. Among them, chest CT images showed less lesions in 2 cases, no lesion in 3 cases, and no improvement in 1 case. The remaining 9 cases were still positive in a second nucleic acid test. Six patients showed similar chest CT inflammation, while 3 patients had new lesions, which were all small nodular ground glass opacities. Conclusions: The early chest CT images of children with 2019-nCoV infection are mostly small nodular ground glass opacities. The clinical symptoms of children with 2019-nCoV infection are nonspecific. Dynamic reexamination of chest CT and nucleic acid are important.

[Analysis of CT features of 15 Children with 2019 novel coronavirus infection]

Objective: To explore imaging characteristics of children with 2019 novel coronavirus (2019-nCoV) infection. Methods: A retrospective analysis was performed on clinical data and chest CT images of 15 children diagnosed with 2019-nCoV. They were admitted to the third people's Hospital of Shenzhen from January 16 to February 6, 2020. The distribution and morphology of pulmonary lesions on chest CT images were analyzed. Results: Among the 15 children, there were 5 males and 10 females, aged from 4 to 14 years old. Five of the 15 children were febrile and 10 were asymptomatic on first visit. The first nasal or pharyngeal swab samples in all the 15 cases were positive for 2019-nCoV nucleic acid. For their first chest CT images, 6 patients had no lesions, while 9 patients had pulmonary inflammation lesions. Seven cases of small nodular ground glass opacities and 2 cases of speckled ground glass opacities were found. After 3 to 5 days of treatment, 2019-nCoV nucleic acid in a second respiratory sample turned negative in 6 cases. Among them, chest CT images showed less lesions in 2 cases, no lesion in 3 cases, and no improvement in 1 case. Other 9 cases were still positive in a second nucleic acid test. Six patients showed similar chest CT inflammation, while 3 patients had new lesions, which were all small nodular ground glass opacities. Conclusions: The early chest CT images of children with 2019-nCoV infection are mostly small nodular ground glass opacities. The clinical symptoms of children with 2019-nCoV infection are nonspecific. Dynamic reexamination of chest CT and nucleic acid are important.

[The clinical characteristics of the evoked nystagmus in the non-affected side during Dix-Hallpike test in the unilateral posterior semicircular canal benign paroxysmal positional vertigo]

Objective: To investigate the clinical characteristics of the evoked nystagmus in the non-affected side during Dix-Hallpike test(D-H test)in unilateral posterior semicircular canal benign paroxysmal positional vertigo(PC-BPPV). Method: Two hundred and thirty-six patients were diagnosed with unilateral PC-BPPV in the Tinnitus and Dizziness clinic.Among them,14 patients exhibited positive nystagmus when the non-affected side was stimulated by D-H test. The clinical data from this subgroup of patients were retrospectively analyzed. Result: The upbeat and torsional nystagmus of 14 patients were all evoked by D-H test in the affected side. 11 cases were right PC-BPPV and 3 cases were left PC-BPPV. Among these 14 patients, 5 patients exhibited the upbeat and torsional nystagmus during D-H test in the non-affected side, which was in the same direction as that evoked in the affected side. Among them, 4 cases were right PC-BPPV and 1 case was left PC-BPPV. However, the downbeat nystagmus of the remaining 9 patients were evoked by D-H test in the non-affected side, in which 7 cases were right PC-BPPV and 2 cases were left PC-BPPV.The nystagmus and vertigo of all patients completely disappeared after performing the Epley or Semont repositioning maneuvers on the affected side. Conclusion: The bilateral positive nystagmus of unilateral PC-BPPV can be evoked by D-H test. The form of nystagmus on the non-affected side is related with the initial position of otoconia in affected semicircular canal and the moving direction of otoconia during the positional test. It is effective to perform Epley or Semont repositioning maneuvers on the affected side. Meanwhile, both the effect of maneuvers and the type of nystagmus evoked by D-H test can verify which side is affected.

[Preliminary analysis of the effects of individualized sound therapy on chronic subjective tinnitus]

Objective:To explore the effect of individualized multi-compound sound therapy on chronic subjective tinnitus and the relationship between tinnitus frequency," notch " hearing loss and the treatment effect of sound therapy.Method: Seventy-eight cases of chronic subjective tinnitus with the pure tone test threshold (PTA)in normal range (≤25 dB HL)were enrolled in this study. Their hearing threshold were re-evaluated using the precise pure-tone audiogram (P-PTA).Tinnitus was evaluated on pitch and loudness matching, and the effectiveness of tinnitus was measured using Tinnitus Handicap Inventory (THI) before they received the individualized customized multi-compound sound therapy for 3 months. THI were re-evaluated on the 30th day and 90th day after treatment.Result: ①The averaged THI score of these patients before the sound treatment was 24.62±15.65 (n=78). The score dropped significantly to 15.82±13.02 and 13.62 ±10.98 on the 30th day and 90th day after treatment, respectively (P<0.01). ②Patient' s gender, age, and the side of tinnitus has no effect on the sound treatment of tinnitus. ③Of these 78 tinnitus patients, 31 patients who showed "notch " hearing loss and 47 patients without "notch " hearing loss in the P-PTA. The averaged THI score between the patients with and without "notch " showed no statistical difference after the treatment (P>0.05).These data suggested that "notch " hearing loss in P-PTA has no effect on the sound therapy.④Of 31 tinnitus patients with "notch " hearing loss, the tinnitus frequency of 22 cases was at the "notch " hearing loss and that of 9 cases was not at the "notch " hearing loss. Sound treatment showed significant between the former and the latter(P<0.05). After 30 days of treatment, tinnitus frequency of four patients whose tinnitus was not at the notch hearing loss drifted to the "notch " hearing loss frequency. Conclusion: Customized multi-compound sound therapy can reduce the THI score of chronic subjective tinnitus patients.The treatment reduced patient's anxiety and improved their quality of life.Sound treatment showed a better improvement in the patients whose tinnitus frequency was located at their notch hearing loss.

A multi-omic analysis reveals the role of fumarate in regulating the virulence of enterohemorrhagic Escherichia coli

The enteric pathogen enterohemorrhagic Escherichia coli (EHEC) is responsible for outbreaks of bloody diarrhea and hemolytic uremic syndrome (HUS) worldwide. Several molecular mechanisms have been described for the pathogenicity of EHEC; however, the role of bacterial metabolism in the virulence of EHEC during infection in vivo remains unclear. Here we show that aerobic metabolism plays an important role in the regulation of EHEC virulence in Caenorhabditis elegans. Our functional genomic analyses showed that disruption of the genes encoding the succinate dehydrogenase complex (Sdh) of EHEC, including the sdhA gene, attenuated its toxicity toward C. elegans animals. Sdh converts succinate to fumarate and links the tricarboxylic acid (TCA) cycle and the electron transport chain (ETC) simultaneously. Succinate accumulation and fumarate depletion in the EHEC sdhA mutant cells were also demonstrated to be concomitant by metabolomic analyses. Moreover, fumarate replenishment to the sdhA mutant significantly increased its virulence toward C. elegans. These results suggest that the TCA cycle, ETC, and alteration in metabolome all account for the attenuated toxicity of the sdhA mutant, and Sdh catabolite fumarate in particular plays a critical role in the regulation of EHEC virulence. In addition, we identified the tryptophanase (TnaA) as a downstream virulence determinant of SdhA using a label-free proteomic method. We demonstrated that expression of tnaA is regulated by fumarate in EHEC. Taken together, our multi-omic analyses demonstrate that sdhA is required for the virulence of EHEC, and aerobic metabolism plays important roles in the pathogenicity of EHEC infection in C. elegans. Moreover, our study highlights the potential targeting of SdhA, if druggable, as alternative preventive or therapeutic strategies by which to combat EHEC infection.

Glucohexaose-induced protein phosphatase 2C regulates cell redox status of cucumber seedling

Protein Phosphatase 2C (PP2C) is an important phosphatase-like protein in eukaryotic organisms that can negatively regulate protein kinase cascade abscisic acid (ABA) signal system through phosphorylation and carry out vital roles in various cell processes. The previous study indicated that the accumulation of reactive oxygen species (ROS) is a part of mechanism of glucohexaose-induced resistance in cucumber cotyledons, and CsPP2C80s might play a crucial role in processes related to ROS produce and signal transduction. To identify the mechanism of CsPP2C80s involved in glucohexaose and ABA signaling regulating cell redox status, the effects of glucohexaose and ROS inhibitor pretreatment on endogenous ABA content and ABA signaling genes expression levels of cucumber seedlings were analysed. These results suggest that cucumber CsPP2C80s are involved in ROS accumulation and ABA signal transduction pathway induced by glucohexaose, CsPP2C80s play a positive regulatory role in process of ABA combined with ABA receptors (PYLs) to activate SNF1-related protein kinases 2 (SnRK2s) and regulate NADPH oxidase to produce extracellular hydrogen peroxide (H2O2), providing unequivocal molecular evidence of PP2C-mediated ABA response mechanisms functioning in cell redox status induced by glucohexaose.

[Features of peripheral nerve injuries in workers exposed to vibration: an analysis of 197 cases]

Objective: To investigate the features of peripheral nerve injuries in workers exposed to vibration. Methods: A total of 197 male workers [median age: 34 years (21-50 years) ; median working years of vibration exposure: 7.3 years (1-20 years) ] engaged in grinding in an enterprise were enrolled. Their clinical data and electromyography results were analyzed to investigate the features of peripheral nerve impairment. Results: Of all workers, 96 (48.73%) had abnormal electromyography results. Of all workers, 88 (44.7%) had simple mild median nerve injury in the wrist, who accounted for 91.7% (88/96) of all workers with abnormal electromy-ography results. Six workers had ulnar nerve injury, superficial radial nerve injury, or/and superficial peroneal nerve injury and accounted for 6.3% of all workers with abnormal electromyography results. Of all workers, 88 had a reduced amplitude of median nerve sensory transduction, and 28 had slowed median nerve sensory transduction. A total of 46 workers were diagnosed with occupational hand-arm vibration disease and hospitalized for treatment. They were followed up for more than 4 months after leaving their jobs, and most of them showed improvements in neural electromyography results and returned to a normal state. Conclusion: Workers exposed to vibration have a high incidence rate of nerve injury in the hand, mainly sensory function impairment at the distal end of the median nerve, and all injuries are mild peripheral nerve injuries. After leaving the vibration job and being treated, most workers can achieve improvements and return to a normal state.

Interferon Gamma and Contact-dependent Cytotoxicity Are Each Rate Limiting for Natural Killer Cell-Mediated Antibody-dependent Chronic Rejection

Natural killer (NK) cells are key components of the innate immune system. In murine cardiac transplant models, donor-specific antibodies (DSA), in concert with NK cells, are sufficient to inflict chronic allograft vasculopathy independently of T and B cells. In this study, we aimed to determine the effector mechanism(s) required by NK cells to trigger chronic allograft vasculopathy during antibody-mediated rejection. Specifically, we tested the relative contribution of the proinflammatory cytokine interferon gamma (IFN-γ) versus the contact-dependent cytotoxic mediators of perforin and the CD95/CD95L (Fas/Fas ligand [FasL]) pathway for triggering these lesions. C3H/HeJ cardiac allografts were transplanted into immune-deficient C57BL/6 rag-/- γc-/- recipients, who also received monoclonal anti-major histocompatibility complex (MHC) class I DSA. The combination of DSA and wild-type NK cell transfer triggered aggressive chronic allograft vasculopathy. However, transfer of IFN-γ-deficient NK cells or host IFN-γ neutralization led to amelioration of these lesions. Use of either perforin-deficient NK cells or CD95 (Fas)-deficient donors alone did not alter development of vasculopathy, but simultaneous disruption of NK cell-derived perforin and allograft Fas expression resulted in prevention of these abnormalities. Therefore, both NK cell IFN-γ production and contact-dependent cytotoxic activity are rate-limiting effector pathways that contribute to this form of antibody-induced chronic allograft vasculopathy.

Lack of the P2X7 receptor protects against AMD-like defects and microparticle accumulation in a chronic oxidative stress-induced mouse model of AMD

The P2X₇ receptor (P2X₇R) is an ATP-gated ion channel that is a key player in oxidative stress under pathological conditions. The P2X₇R is expressed in the retinal pigmented epithelium (RPE) and neural retina. Chronic oxidative stress contributes to the pathogenesis of age-related macular degeneration (AMD). Mice lacking Cu, Zn superoxide dismutase (Sod1) developed chronic oxidative stress as well as AMD-like features, but whether the P2X₇R plays a causative role in oxidative stress-induced AMD is unknown. Thus, the main purpose of this study was to test if concurrent knockout (KO) of P2X₇R could block AMD-like defects seen in Sod1 KO mice. Using multiple approaches, we demonstrate that Sod1 KO causes AMD-like defects, including positive staining for oxidative stress markers, 3-nitrotyrosine and carboxymethyl lysine, thinning of the RPE and retina, thickening of Bruch's membrane, presence of basal laminar and linear deposits, RPE barrier disruption and accumulation of microglia/macrophages. Moreover, we find that Sod1 KO mice accumulate more microparticles (MPs) within RPE/choroid tissues. Concurrent KO of the P2X₇R protects against AMD-like defects and MP accumulation in Sod1 KO mice. Together, we show for the first time, that deficiency of P2X₇R prevents in vivo oxidative stress-induced accumulation of MPs and AMD-like defects. This work could potentially lead to novel therapies for AMD and other oxidative stress-driven diseases.

Segment-specific targeting via RNA interference mediates down-regulation of OPN expression in hepatocellular carcinoma cells

Osteopontin (OPN) plays an important role in the metastasis and recurrence of tumors after resection of hepatocellular carcinoma (HCC). In this study, the down-regulation effect on OPN expression in HCC cells of RNA interference (RNAi) molecules designed to target different segments of OPN was investigated to identify a more effective site for OPN knockdown. Specific small interfering RNAs (siRNAs A, B, and C) of OPN were synthesized and transfected into an HCC cell line (HEP-G2; representing the OPNi-A, OPNi-B, and OPNi-C groups). Fluorescent quantitative polymerase chain reaction and immunohistochemical methods were used to detect the mRNA and protein expression of OPN before and after RNAi. Results showed that after transfection, the fluorescence intensity of the OPNi-A group was greater than those of the OPNi-B and OPNi-C groups. After 48 h of transfection, the ΔCT values of OPN mRNA expression in the OPNi-A-C groups increased from 8.31 ± 1.58, 8.78 ± 1.49, and 8.25 ± 1.51 to 12.14 ± 1.43, 10.22 ± 1.97, and 10.48 ± 1.88, respectively (P < 0.05), and the OPN protein levels (immunohistochemistry scores) decreased from 6.44 ± 1.67, 5.43 ± 2.05, and 5.45 ± 2.52 to 2.84 ± 1.52, 4.43 ± 1.65, and 3.95 ± 1.43 points, respectively. These results indicated that RNAi based on different segments of the OPN gene had different down-regulatory effects on OPN expression. Synthesis of targeted siRNA aimed at specific OPN segments might have important significance for dealing with the invasiveness and metastasis of HCC cells.

The protective effect of curcumin on ischemia-reperfusion-induced liver injury

OBJECTIVE

Reperfusion of the ischemic liver results in the generation of oxidative and nitrosative stresses and reaction product of peroxynitrite, which induce rapid cytotoxicity and liver injury. In this study we demonstrated that curcumin, an antioxidant, attenuated ischemia/reperfusion (I/R)-induced liver injury.

MATERIALS AND METHODS

Ischemia was induced by clamping the common hepatic artery and portal vein of rats for 30 minutes. Thereafter, flow was restored and the liver was reperfused for 80 minutes. Blood samples collected prior to ischemia and after reperfusion were analyzed for methyl guanidine (MG), nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), and adenosphate triphosphate (ATP). Blood levels of serum glutamic oxaloacetic transaminase (sGOT), serum glutamate pyruvate transaminase (sGPT), and lactic dehydrogenase (LDH), which served as indexes of liver injury, were measured.

RESULTS

The protocol resulted in elevation of blood NO (P < .001), TNF-α (P < .001), and MG (P < .001). sGOT, sGPT, and LDH were elevated significantly (P < .001), whereas ATP was significantly diminished (P < .001). Pretreatment with curcumin (25 mg/kg) significantly attenuated the reperfusion liver injury, while the ATP content reversed. In addition, MG, TNF-α, and NO release were attenuated.

CONCLUSIONS

These results indicated that curcumin exerted potent anti-inflammatory effects in I/R-induced liver injury due to its antioxidant effects.

Intracranial pressure fluctuation during hemodialysis in renal failure patients with intracranial hemorrhage

Coagulopathy in renal failure patients often makes them vulnerable to intracranial hemorrhage. Emergency decompression to remove the hematoma and to stop bleeding is always indicated. After the surgery, hemodialysis (HD) should be arranged to maintain the BUN/Cr. level, and I/O balance. During HD, intracranial pressure in all of the patients in this study fluctuated. This phenomenon always resulted in neurological deterioration in acute or chronic renal failure. We present intracranial pressure (ICP) changes during HD in five acute or chronic renal failure patients with intracranial hemorrhage. They all underwent craniectomy or craniotomy with ICP monitors implantation. Different HD protocols were arranged for these patients and then we observed clinical results. ICP elevated during HD and resulted in severe brain swelling. This situation was one of the clinical presentations of dialysis disequilibrium syndrome (DDS). Four patients died because of this complication and one survived. ICP fluctuation seemed to be correlated with the fluid amount and frequency of HD. The prevalence and pathophysiology of DDS remain unclear. Renal failure patient with intracranial hemorrhage may be complicated with DDS when HD was performed. An attempt to reduce the fluid amount and to increase the frequency of HD might help these patients.

Redshift of edge emission from AlGaInP light-emitting diodes and correlation with electron-hole recombination lifetime

The edge emission from AlGaInP light-emitting diodes showed a red-shifted peak in addition to the peak of surface emission. This shift resulted from the quantum-well absorption of the guided wave. Although the shift degrades the color quality and the extraction efficiency of the device, it helps elucidate many important optical properties of the material and the dynamics of carrier recombination, including the electron-hole recombination lifetime, the optical joint density of state, the spontaneous emission spectrum and the absorption spectrum. A simple concept of the bimolecular recombination is established. The corresponding coefficient can be expressed by a simple formula and was therefore determined.

Hypofractionated CyberKnife stereotactic radiosurgery for acoustic neuromas with and without association to neurofibromatosis Type 2

CyberKnife stereotactic radiosurgery (CKSRS) has been proved effective in treating intra-cranial lesions. To treat acoustic neuroma (AN) patients with or without neurofibromatosis Type 2 (NF2) associations, the functional preservation of hearing, trigeminal nerve, and facial nerve are important. Twenty-one patients were treated with hypofractionated CKSRS. Fourteen non-NF2 and seven NF2 patients were enrolled. Cranial nerve function, audiograms, and magnetic resonance images (MRI) were monitored. Mean follow-up was 15 month. Tumors with volumes ranging from 0.13 to 24.8 cm3 (mean 5.4 cm3) were irradiated with the marginal dose 1800-2000 cGy/3 fractions. Tumors were treated with an 80 to 89% isodose line (mean 83%) and mean 97.9% tumor coverage. Two patients experienced hearing deterioration (16.7%) in the non-NF2 group, and 3 patients (50%) in the NF2 group. No facial or trigeminal dysfunction, brain stem toxicity, or cerebellar edema occurred. Tumor regression was seen in 9 patients (43%) and stable in 12 patients (57%). 100% tumor control rate was achieved. Hypofractionated CKSRS was not only effective in tumor control but also excellent in hearing preservation for non-NF2 AN. But for NF2 patients, although the tumor control was remarkable, hearing preservation was modest as in non-NF2 patients.

Evaluation of optimal cerebral perfusion pressure in severe traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and disability. In the 2000 guidelines, one of the suggestions for TBI treatment was to maintain cerebral perfusion pressure (CPP) < or = 70 mmHg. But in the 2003 guidelines, the suggestion was changed to < or = 60 mmHg. There have been some discrepancies of opinions about this recommendation in recent publications. In this study, we retrospectively reviewed 305 severe TBI (STBI) patients with Glasgow Coma Scales (GCS) < or = 8 between January 1, 2002 and March 31, 2003. The study group was stratified according to use or nonuse of intracranial pressure (ICP) monitoring, ICP levels, ages, and GCS levels in order to test the correlation between CCP and the prognosis. The patients < 50-year-old, with higher GCS level, with ICP monitoring, and with ICP levels < 20 mmHg had lower mortality rates and better prognosis (GOS) (p < 0.05 or 0.001). The patients in the GCS 3-5 subgroup had a significantly lower mortality and better prognosis if the CPP value was maintained higher than 70 mmHg (p < 0.05) The optimal CPP maintained < or = 60 mmHg did not fit in all STBI patients. Our study concludes that it is critical to maintain CPP substantially higher in lower GCS level patients.

Effect of hyperbaric oxygen on patients with traumatic brain injury

Hyperbaric oxygen therapy (HBOT) is the medical therapeutic use of oxygen at a higher atmospheric pressure. The United States Food and Drug Administration have approved several clinical applications for HBOT, but HBOT in traumatic brain injury (TBI) patients has still remained in controversial. The purpose of our study is to evaluate the benefit of HBOT on the prognosis of subacute TBI patients. We prospectively enrolled 44 patients with TBI from November 1, 2004 to October 31, 2005. The study group randomly included 22 patients who received HBOT after the patients' condition stabilization, and the other 22 corresponding condition patients were assigned into the matched control group who were not treated with HBOT. The clinical conditions of the patients were evaluated with the Glasgow Coma Scale (GCS) and Glasgow Outcome Scale (GOS) before and 3 to 6 months after HBOT. The GCS of the HBOT group was improved from 11.1 to 13.5 in average, and from 10.4 to 11.5 (p < 0.05) for control group. Among those patients with GOS = 4 before the HBOT, significant GOS improvement was observed in the HBOT group 6 months after HBOT. Based on this study, HBOT can provide some benefits for the subacute TBI patients with minimal adverse side effects.

Neurotrauma research in Taiwan

Because of the rapid industrial and economic growth, Taiwan and other developing countries have faced an enormous increase in the number of motorcycles, which has subsequently caused a rapid increase of the motorcycle-related traumatic brain injuries (TBI). In order to tackle this serious problem, stepwise approaches for TBI were implemented in Taiwan from 1991 to 2007. Step 1 was to do a nationwide TBI registry in order to identify the risk factors and determinants. We found that the major cause of TBI in Taiwan was motorcycle-related injury, and very few motorcyclists wore a helmet. Step 2 was to launch the implementation of the helmet use law on June 1, 1997. A rapid decline of TBI hospitalizations and deaths was demonstrated soon thereafter. Step 3 was to enroll into international collaborations with the Global Spine and Head Injury Prevention Project (Global SHIP Project) groups for TBI. The comparative results thus obtained could be used to develop prevention strategies for developing countries. Step 4 was to implement clinical researches for TBI, which included a Propofol study, hyperbaric oxygen therapy (HBOT), brain parenchymal oxygen (PbtO2) monitoring, etc. Step 5 was to develop guidelines for the management of severe TBI in Taiwan. Through a 2-year period of review, discussion, and integration, a 9-chapter guideline was published in June 2007. In summary, our experience and process for management of TBI in Taiwan can be used as a reference for other developing countries.

Molecular cloning and expression analysis of rainbow trout (Oncorhynchus mykiss) CCAAT/enhancer binding protein genes and their responses to induction by GH in vitro and in vivo

CCAAT/enhancer-binding proteins (C/EBPs) are transcription factors consisting of six isoforms and play diverse physiological roles in vertebrates. In rainbow trout (Oncorhynchus mykiss), in addition to the reported C/EBPbeta1, we have isolated cDNA of four other isoforms, C/EBPalpha, C/EBPbeta2, C/EBPdelta1, C/EBPdelta2, from the liver. Comparison of the deduced amino acid sequence of rainbow trout C/EBPs with those of other vertebrates revealed that C/EBP isoforms are highly conserved. The profiles of tissue-specific expression of individual C/EBP isoform mRNA, determined by quantitative real-time (RT)-PCR showed distinct patterns. Furthermore, injection of bovine GH into yearling rainbow trout resulted in a significant increase of mRNA levels of C/EBPbeta1, C/EBPbeta2, and C/EBPdelta2 but not C/EBPalpha and C/EBPdelta1 in the liver. GH-dependent increase of mRNA levels of C/EBPbeta1, C/EBPbeta2, C/EBPdelta2, and IGF-II were also confirmed by treating rainbow trout hepatoma cells expressing a goldfish GH receptor with bGH. Together with our previous findings, the results presented in this paper strengthen our previous hypothesis that GH may regulate the expression of the IGF-II gene via mediating the expression of C/EBPbeta1, C/EBPbeta2, and C/EBPdelta2 mRNA.

Associations between VHL genotype and clinical phenotype in familial von Hippel-Lindau disease

BACKGROUND

Von Hippel-Lindau (VHL) disease is an autosomal dominant hereditary disorder associated with tumours and cysts in the central nervous system (CNS) and other visceral organs. Germline mutations in the VHL gene on chromosome 3p25-26 are considered the cause of this disease.

MATERIALS AND METHODS

We studied six patients with VHL disease and their relatives. Loss of heterozygosity (LOH) was determined by five flanking microsatellite polymorphic markers in the VHL locus. Multiplex ligation-dependent probe amplification (MLPA) and quantitative real-time polymerase chain reaction (qPCR) amplification were used to detect the genomic deletions. Single-strand conformation polymorphism (SSCP) analysis was applied to test for sequence variations.

RESULTS

Three germline deletions in the VHL gene (142.9, 53.3 and 3.3 kb) were found by MLPA. These deletions were defined clearly by qPCR analyses. The142.9 kb germline deletion was significantly associated with patients with CNS haemangioblastomas (P < 0.01 by Fisher's exact test), and one missense mutation (Gln209Arg) was detected from a patient with a pancreatic cyst in the same family. LOH was also detected from a patient with bilateral renal cell carcinomas.

CONCLUSION

Diverse genetic conditions are associated with the clinical manifestations of VHL disease. Genomic deletions that can be detected by MLPA or qPCR are major causes for this syndrome. Missense mutations and LOH accompanying the disease lead to complex clinical symptoms and genotypic determination can facilitate a clinical diagnosis because of their strong association.

Degradation of di-butyl-phthalate by soil bacteria

Twelve Gram-positive phthalate ester degraders were isolated from soil. Using Biolog GP2 plates, eight of them were identified as belonging to the Corynebacterium-Mycobacterium-Nocardia group, while the remaining four were unidentifiable. When cultured in the presence of di-butyl-phthalate (DBP) in basal salts solution, five of these isolates accomplished more than 90% of DBP degradation within 48 h (fast group), three were placed in the medium group, and the remaining four were placed in the slow group which caused less than 30% of DBP degradation within the same period of time. A 420 bp DNA fragment was amplified from six isolates and none of them fell within the slow group. When compared with the large subunit of phthalate dioxygenase gene (phtA) of Arthrobacter keyseri, 83% and 91% similarities were evident in the nucleotide and amino acid sequences, respectively. However, no correlation between cell surface hydrophobicity and phthalate degradation ability was evident. Six surfactants (Brij 30, Brij 35, Tergitoltype NP-10, Triton N-101, Triton X-100 and SDS) were tested for their abilities to increase degradation rate. When added at the critical micellar concentration (CMC), they all displayed strong growth inhibition against the three bacteria tested, with Brij 30 been the least toxic to isolates G2 and G11, and Brij 35 had the least inhibitory effect for G1. When half the CMC of Brij 30 was incorporated into the basal salts, the inhibitory effect on DBP degradation remained. Soil helped to minimize surfactant toxicity of surfactant and increase the degradation potential of some of the test bacteria. When DBP-amended soil had been aged for three months, decreases in bioavailability were observed but the effect varied tremendously between different organisms. For isolates G1, G2, G5, G7 and G17 the aging effects were almost non-exist. The present study indicates that selection of a suitable degrader may minimize the undesired effect of aging on bioremediation process.

Idiopathic syringomyelia: case report and review of the literature

Syringomyelia is an uncommon disease that is caused most often by type I Chiari malformation, which develops in the hindbrain, and less frequently by other factors which are not limited to the hindbrain, including trauma, infection, or scoliosis. Idiopathic syringomyelia is rare. We present in this article a patient with idiopathic syringomyelia characterized by hypoesthesia and progressive weakness in the left lower limb. Decompression was attempted by means of laminectomy and a syringoarachnoid shunt. Motor, sensory, and bladder functions were monitored by the change in Japanese Orthopedic Association scores, which increased from 10 points preoperatively to 14 points 30 days postoperatively. This case demonstrates the effectiveness of surgical decompression in a patient with remarkable neurological deficit.

A prospective study of nocturia and the quality of life of elderly patients with obstructive sleep apnea or sleep onset insomnia

OBJECTIVE

To prospectively evaluate the relationship between obstructive sleep apnea syndrome (OSAS), nocturia and quality of life in elderly patients free of the urologic and medical conditions that lead to increased nocturia.

METHODS

Prospective study of nocturia in men 65 years and older with isolated OSAS or sleep onset insomnia. After a 7-day nocturia evaluation and nocturnal polysomnography, Epworth Sleepiness Scale (ESS), Beck Depression Inventory (BDI), Quality of Life (SF-36) were administered.

RESULTS

OSAS patients with frequent nocturia had significantly greater body mass index (BMI), greater apnea-hypopnea index (AHI), lower lowest oxygen saturation and lower SF-36 subscale scores. Treatment with nasal continuous positive airway pressure (CPAP) for OSAS and behavioral techniques for insomnia improved ESS and BDI scores for all three groups. SF-36 subscale scores improved more in subjects with multiple nocturia. AHI and BMI explain 38% of the variance for nocturia.

CONCLUSION

Nasal CPAP reduces OSA and nocturia and improves quality of life of elderly patients.

Consumer acceptance of fresh-cut iceberg lettuce treated with 2% hydrogen peroxide and mild heat

An antibacterial treatment consisting of 2% hydrogen peroxide at 50 degrees C for 60 s was evaluated for its effects on the sensory quality of fresh-cut iceberg lettuce. Treated lettuce was packaged in polyethylene film by a protocol used in the fresh-cut produce industry and then stored along with untreated controls for 3, 10, and 15 days at 5 degrees C. Gas chromatographic analysis confirmed that the desired initial volume (approximately 6 liters) and oxygen gas content (approximately 10%) were maintained during storage. Consumers from the local community who were the primary shoppers for their households and who purchased and ate lettuce regularly evaluated the appearance, color, aroma, flavor, and texture of the lettuce and their overall liking of the lettuce. Forty consumers were recruited to evaluate processing replication 1 on 26 April, and another 40 were chosen to evaluate processing replication 2 on 3 May. Because replication differences were observed in instrumental color measurements and in mean sensory ratings, replications were not pooled for the two test dates. Lettuce purchased for processing replication 2 was considerably greener than that used in replication 1. Overall, the antibacterial treatment was more effective than the control treatment in maintaining sensory quality over 15 days of storage, provided that the lettuce was initially intensely green. Three-fourths of the participants indicated that they would be willing to buy precut packaged lettuce that had already been treated at the packinghouse or processing plant with an antibacterial solution, and of these participants, 62.5% indicated that they would be willing to pay 5 to 10 cents more per bag.

Recognition of potassium ion in water by 15-crown-5 functionalized gold nanoparticles

Reported here is an efficient recognition of K+ by 15-crown-5 functionalized gold nanoparticles in aqueous matrix containing physiologically important cations, such as Li+, Cs+, NH4+, Mg2+, Ca2+, and excess amount of Na+. Upon exposure to K+, the colloidal solution changes from red to blue, in response to surface plasmon absorption of dispersed and aggregated nanoparticles. The concentration ranges of K+ detected in this study are 0.099-0.48 mM and 7.6 microM-0.14 mM, when concentrations of colloidal gold are 54.9 and 7.1 nM, respectively. Recognition of K+ and formation of the aggregates are proposed via a sandwich complex of 2:1 between 15-crown-5 moiety and K+. Also discussed is the possibility of a preorganized structure of 15-crown-5 at the water-organic interface for the efficient complexation with K+.

Dehydroepiandrosterone sulfate (DHEAS) suppresses P2X purinoceptor-coupled responses in PC12 cells

Some steroids rapidly alter neuronal excitability through interaction with neurotransmitter-gated ion channels in addition to their well-known genomic effects via intracellular steroid receptors. Such effects were found in GABA receptor, nicotinic receptors, yet not investigated in P2X purinoceptors. In this study, the effects of dehydroepiandrosterone sulfate on the P2 purinoceptor was investigated. Results show that dehydroepiandrosterone sulfate acutely inhibits P2X purinoceptor functions in PC12 cells. Dehydroepiandrosterone sulfate suppressed ATP-induced cytosolic free calcium concentration ([Ca(2+)](i)) rise, cytosolic free sodium concentration ([Na(+)](i)) rise, and dopamine secretion in the presence of external calcium, but had no effect on ATP-induced [Ca(2+)](i) rise in the absence of external calcium or on UTP-induced [Ca(2+)](i) rise in the absence or presence of external calcium. Our data show that dehydroepiandrosterone sulfate exerted its effect on P2X, but not on the P2Y purinoceptors found in PC12 cells. Estradiol and estrone have similar effects on P2X purinoceptor, but dehydroepiandrosterone and progesterone do not.

Inadvertent hypothermia causes pulseless electrical activity in a patient during cervical spine surgery--a case report

Recent studies have shown that hypothermia triples the incidence of major cardiac events. We present a happening in which a 71-year-old patient developed pulseless electrical activity (PEA) while he was undergoing cervical laminectomy for spinal stenosis in the sitting position. Thromboembolism or venous air embolism and acute myocardial infarction were respectively excluded by transesophageal echocardiography and cardiac enzymes analysis to be the causes of the cardiac event. The abnormal finding that stood out was low nasopharyngeal temperature (31 degrees C) during the procedure, which was thought to contribute to the development of the PEA episode.

Glutamine metabolism in sepsis and infection

Severe infection causes marked derangements in the flow of glutamine among organs, and these changes are accompanied by significant alterations in regional cell membrane transport and intracellular glutamine metabolism. Skeletal muscle, the major repository of glutamine, exhibits a twofold increase in glutamine release during infection, which is associated with a significant increase in endogenous glutamine biosynthesis. Despite an increase in glutamine synthetase activity in skeletal muscle, the intracellular glutamine pool becomes depleted, indicating that release rates exceed rates of synthesis. Simultaneously, the circulating pool of glutamine does not increase, indicating accelerated uptake by other organs. The liver appears to be the major organ of glutamine uptake in severe infection; studies in endotoxemic rodents have shown net hepatic glutamine uptake to increase by as much as 8- to 10-fold. This increase is due partially to increases in liver blood flow, but also to a three- to fourfold increase in hepatocyte System N activity in the liver. Cytokines and glucocorticoids mediate the increased uptake of glutamine by the liver in septic states as well as other compounds. Sepsis does not appear to induce an increase in System N gene expression, indicating that the increase in hepatic glutamine transport observed during severe infection is probably regulated at the protein level. The bowel displays a decrease in glutamine utilization during sepsis, a response that may be related to the decrease in circulating insulin-like growth factor-1 (IGF-1) levels that is characteristic of sepsis. Recent studies suggest that IGF-1 has a direct effect on stimulating glutamine transport across the gut lumen and thus may represent a therapeutic avenue for improving gut nutrition during severe infection. The cells of the immune system (lymphocytes, macrophages) are also major glutamine consumers during inflammatory states in which cell proliferation is increased. Under these conditions, glutamine availability can become rate limiting for key cell functions, such as phagocytosis and antibody production.

Destruction of Escherichia coli O157:H7 and Salmonella enteritidis in cow manure composting

Application of cow manure and composted manure in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Salmonella Enteritidis and Escherichia coli O157:H7. In this study, rifampicin-resistant (RifR) E. coli O157:H7 and Salmonella Enteritidis at a level of 7 log CFU/g of raw compost feed were used to determine the effect of a bench-scale composting system on their survival. RifR E. coli O157:H7 was not detected after 72 h of composting at 45 degrees C, and RifR Salmonella Enteritidis was not detected after 48 h. The use of selective media for enrichment failed to recover in the composting samples held at 45 degrees C for 96 h. However, the pathogens showed no change in bacterial numbers when the composting system was held at room temperature. Thus, properly composted manure can be safely used in food crop production while minimizing the likelihood of microbial contamination.

Combined conventional and jet ventilation in airway management in tracheal tumor

Tumors on the carina are uncommon, and their anesthetic management can present a considerable challenge. The principle anesthetic consideration is ventilation and oxygenation in the face of an open airway. A 60-year-old man patient suffered a carinal tumor, which occupied 70% of the both main bronchi and bled spontaneously while coughing. Surgical resection and reconstruction were done. The carinal surgical approach was a right posterolateral thoracotomy, and the patient was placed in the left decubitus position. Because we could not insert the jet catheter past the mass, high frequency jet ventilation to ventilate the dependent lung could not be applied. Our choice was differential lung ventilation with a combination of conventional and high frequency jet ventilation modes to preserve oxygenation during tumor excision and tracheal reconstruction. An episode of desaturation was successfully treated during removal of tumor. The postoperative course was uneventful. The patient was sent to the intensive care unit after surgery and discharged on the 11th day. He received further combined chemotherapy and radiotherapy during his next admission. Fiberoptic examination on the 5 months later no evidence of recurrence. In summary, we described our airway management on carinal tumor excision, especially the tumor was so large that dependent lung jet ventilation could not employ.

Hemodynamic responses of thiopental and propofol in different-aged patients during endotracheal intubation

BACKGROUND

Thiopental and propofol are 2 popularly used anesthetic induction agents that have different pharmacological and pharmacokinetic actions. It is not clear how the hemodynamic responses differ in different-aged patients using these 2 drugs for anesthetic induction. The aim of this study was to investigate the hemodynamic responses to propofol and thiopental of different-aged patients during endotracheal intubation.

METHODS

Sixty patients, 20 to 83 years old, were included in this study. Patients were randomly divided into 6 groups according to age and different inductive anesthetics. Non-invasive blood pressure (NIBP) monitoring was performed every minute before anesthesia, during anesthetic induction with 5 mg.kg-1 thiopental or 2 mg.kg-1 propofol intravenously, and after intubation.

RESULTS

Propofol induction produced a smaller mean arterial pressure increase immediately after intubation than did thiopental induction in adult and elderly groups (101.0 +/- 18.5 and 104.0 +/- 21.1 mmHg in the propofol groups vs. 138.3 +/- 17.1 and 138.9 +/- 16.1 mmHg in the thiopental groups at 1 minute after intubation, p < 0.001 and p = 0.001, respectively). Differences in heart rate between propofol and thiopental groups were found in young and adult groups (85.1 +/- 9.2 and 81.7 +/- 10.9 in the propofol groups vs. 94.5 +/- 9.9 and 95.0 +/- 14.0 beats per minute in the thiopental groups at 1 minute after intubation, p = 0.041 and p = 0.029, respectively).

CONCLUSION

Propofol induction produced more stable hemodynamics after intubation in adult and elderly patients than did thiopental induction. Therefore, it is safer to use propofol for induction and intubation in adult and elderly patients.

Pneumopericardium after bronchoscopic carbon dioxide laser surgery--a case report

A female baby sustained pneumopericardium after bronchoscopic CO2 laser surgery for tracheal stenosis. Perioperative pneumopericardium though rare is a life-threatening condition in babies. The symptoms are usually not specific such as hypotension, bradycardia, muffled heart sound, cardiovascular collapse, etc. The causes and clinical findings of pneumopericardium were reviewed, as are the radiographic features so as to differentiate the condition from pneumomediastinum. Early recognition of pneumopericardium is important, because emergent pericardiocentesis may be required if there is clinical evidence of cardiac tamponade.

Anterior mediastinal tumour identified by intraoperative transesophageal echocardiography

PURPOSE

To report a child with anterior mediastinal tumour misdiagnosed as pericardial effusion who had been sent to the operating theatre for drainage. After induction of general anesthesia she developed cardio-respiratory collapse. The diagnosis was made with the aid of transesophageal echocardiography (TEE).

CLINICAL FEATURES

A 14-yr-old girl suffered from cough and intermittent fever for one month before admission. Four days before admission, she became orthopneic and was admitted to the intensive care unit. Precordial echocardiography showed an anterior and posterior echolucent space between the pericardium and epicardium that was thought to be a pericardial effusion. She was sent to the operating room for emergency drainage. After induction of general anesthesia, breath sounds were not heard on the left side of the chest. The patient developed increasing hypoxemia and hypotension despite cardiocentesis. A TEE determined that an anterior mediastinal mass was the cause of her hypoxemia and hypotension. The tumour was debulked and the patient made an uneventful postoperative recovery.

CONCLUSION

In this case, the correct diagnosis of an anterior mediastinal mass was made with TEE. The place of TEE may be indicated in patients with unexplained hypoxemia and hypotension.

Interleukin-10-induced T cell unresponsiveness can be reversed by dendritic cell stimulation

The secretion of immunosuppressive factors like interleukin-10 (IL-10), either by tumor cells or by tumor-infiltrating leukocytes, has been recognized as one of the mechanisms involved in tumor immunological escape and a serious obstacle for successful immunotherapy. Therefore, any therapeutic attempts aimed at inducing antitumor immunity in tumor-bearing hosts must overcome this immunosuppressive state. This study aimed to determine whether dendritic cell (DC) immunization, a promising approach to induce antitumor immunity, could break IL-10-induced anergic state in CD4+ T cells, essential cells in generating tumor-specific immunity. We found that the ability of DC to reverse IL-10-induced anergic state in human CD4+ T cells is dependent on the IL-10 concentration that T cells have been exposed to and the degree of DC maturation. The efficacy of mature DC in reversing T cell anergy can be mimicked by higher cell numbers of immature DC. In addition, activated T cells induced by DC stimulation are sensitive to IL-10 treatment. Collectively, our results suggest the use of mature DC and the necessity of antagonizing the action of tumor-derived IL-10 in immunotherapy of cancer with DC immunization.

T cell receptor binding kinetics and special role of Valpha in T cell development and activation

The kinetics of the interaction between T cell receptor (TCR) and major histocompatibility complex (MHC) has an important role in determining thymocyte-positive and -negative selection in the thymus, as well as in T cell activation. The alpha chain of the TCR is the major player in determining how the TCR fits onto the MHC ligand, and thus has a major role in determining whether a T cell develops as class I or class II restricted. In this article, we summarize recent data from our laboratory and others on the role of polymorphism in the Valpha combining site in determining MHC class restriction, and on kinetic parameters in thymocyte selection.

Anesthesia of CO2 laser surgery in a patient with Hunter syndrome: case report

Hunter syndrome (mucopolysaccharidosis, type II; MPS II) is one of a heterogeneous group of recessively inherited mucopolysaccharide storage diseases. Patients with mucopolysaccharidosis show progressive involvement and derangement of many organs, especially upper airway anomalies, which are the major cause of perioperative death. In recent years, a CO2 laser is often applied to upper airway lesions. A 16-year-old patient suffering from Hunter syndrome was scheduled for CO2 laser surgery because of sleep apnea and respiratory stridor. Otolaryngological examination revealed bulging of the bilateral false cord with stenosis of the glottis. We adopted sevoflurane mask induction and high-frequency jet ventilation to overcome the perioperative airway problems. The anesthetic course was uneventful, and the patient was discharged 2 days after the operation.

Respiratory management after self-extubation

BACKGROUND AND PURPOSE

Self-extubation is a potentially life-threatening event, but may also provide an opportunity to wean patients who should have been extubated earlier. The purpose of this study was to determine the risk factors for re-intubation after self-extubation.

METHODS

The medical charts of 69 self-extubated patients treated in Shin Kong Hospital, Taipei, from September 1996 through August 1998 were reviewed. Demographic data, ventilator settings before self-extubation, arterial blood gas values, and the type of respiratory management used after self-extubation were examined to determine their association with re-intubation.

RESULTS

Of the 69 self-extubated patients, 38 fared well without further ventilatory support after self-extubation. Four factors were associated with extubation outcome: 1) mean pre-extubation FiO2 (fraction of inspired oxygen), which was significantly higher in the re-intubated group (RI) than in the not re-intubated group (NRI) (0.48 vs 0.33, p = 0.002)--all self-extubated patients receiving an FiO2 of more than 0.40 were re-intubated; 2) PaO2/FiO2 (ratio of arterial oxygen tension to inspired oxygen concentration), which was lower in the RI group than in the NRI group (259.4 vs 346.4, p = 0.005); 3) requirement for assist/control ventilatory mode--patients needing this type of ventilatory support had a greater likelihood of reintubation than those requiring partial ventilatory support (odds ratio [OR], 3.790; confidence interval [CI], 1.055-13.621; p = 0.041); and 4) female sex (OR 0.188; CI 0.048-0.732; p = 0.016).

CONCLUSIONS

About half of self-extubated patients may not require re-intubation. Pre-extubation FiO2, PaO2/FiO2, and ventilator mode, as well as gender, may be useful in determining the likelihood that a self-extubated patient will require re-intubation.

Effects of VEGF121 and/or VEGF165 gene transfection on collateral circulation development

BACKGROUND AND PURPOSE

Angiogenesis is regulated by various factors, including vascular endothelial growth factor (VEGF). Five isoforms of VEGF have been discovered: VEGF121, VEGF145, VEGF165, VEGF189, and VEGF206. The teleologic basis for the various VEGF isoforms remains unclear, but different VEGF isoforms may mediate distinct endothelial cell functions such as angiogenesis, vascular permeability, and differentiation. We sought to determine the effects of various VEGF isoforms on angiogenesis under ischemic conditions in rabbits.

METHODS

The effects of VEGF121 and/or VEGF165 gene transfection on collateral circulation development in ischemic rabbit hindlimb muscles were investigated by using naked plasmids encoding VEGF121 or VEGF165 (pVEGF121 or pVEGF165), either individually or in combination. pCMV beta was used as the control plasmid. The femoral artery on one side of New Zealand White rabbits was ligated. Ten days later, the ischemic muscles received direct intramuscular injection of pVEGF121 (500 micrograms), pVEGF165 (500 micrograms), or pVEGF121 (250 micrograms) + pVEGF165 (250 micrograms) in experimental groups, while pCMV beta (500 micrograms) was used in the control group. Therapeutic effects were evaluated 30 days later by anatomic and physiologic analysis.

RESULTS

Internal iliac angiography showed strong development of collateral circulation in all of the pVEGF-treated groups. In contrast, collateral arteries developed weakly in the control group. Combination treatment with both pVEGF121 and pVEGF165 did not result in additional improvement compared with pVEGF121 or pVEGF165 treatment alone (angiographic scores: pVEGF121 = 0.85 +/- 0.10; pVEGF165 = 0.81 +/- 0.11; pVEGF121 + pVEGF165 = 0.83 +/- 0.09; control = 0.53 +/- 0.09; p < 0.01). A favorable response in the development of circulation at the capillary level with pVEGF121 and/or pVEGF165 versus pCMV beta was also found. Blood pressure measurement and regional blood flow measurement using colored microspheres revealed similar results.

CONCLUSIONS

Our results show that direct intramuscular injection of naked DNA encoding VEGF121 or VEGF165, individually or in combination, is an effective method for gene transfer in an animal model of ischemic limbs and results in augmented collateral vascular development and tissue perfusion.

Antibacterial mechanism of allyl isothiocyanate

Allyl isothiocyanate (AITC), a natural compound in plants belonging to the family Cruciferae, has been shown to have strong antimicrobial activity in liquid media as well as in its vapor form. To understand its antimicrobial mechanism, AITC was tested for bactericidal activities to Salmonella Montevideo, Escherichia coli O157:H7, and Listeria monocytogenes Scott A at different stages of growth and was compared with streptomycin, penicillin G, and polymyxin B, each of known antibacterial mechanisms. Bactericidal activities were determined by measuring bacterial viability and leakage of metabolites. To determine its effects on membrane permeability, beta-galactosidase activity was examined after exposure of E. coli K-12 strain 3.300 to the three antibiotics and to AITC. The two gram-negative bacteria, Salmonella Montevideo and E. coli O157:H7, were more sensitive to AITC and to polymyxin B than the gram-positive L. monocytogenes. AITC and polymyxin B were effective bactericidal agents to bacteria at all growth stages, whereas penicillin G and streptomycin did not exhibit bactericidal activity to stationary cells. High A260 and A280 values of cellular filtrate and beta-galactosidase activity were obtained after treatments of AITC and polymyxin B. These data indicated that AITC was most similar to polymyxin B with respect to its antibacterial effect on cell membranes and on leakage of cellular metabolites. Gaseous AITC caused metabolite leakages, measurable increases in 3-galactosidase activity, and reduction of viable bacteria. The effectiveness of AITC in inhibiting bacteria at all growth stages and its strong activity in vapor phase support its application in food preservation.

Cloning and functional characterization of a constitutively expressed nitrate transporter gene, OsNRT1, from rice

Elucidating how rice (Oryza sativa) takes up nitrate at the molecular level could help improve the low recovery rate (<50%) of nitrogen fertilizer in rice paddies. As a first step toward that goal, we have cloned a nitrate transporter gene from rice called OsNRT1. OsNRT1 is a new member of a growing transporter family called PTR, which consists not only of nitrate transporters from higher plants that are homologs of the Arabidopsis CHL1 (AtNRT1) protein, but also peptide transporters from a wide variety of genera including animals, plants, fungi, and bacteria. However, despite the fact that OsNRT1 shares a higher degree of sequence identity with the two peptide transporters from plants (approximately 50%) than with the nitrate transporters (approximately 40%) of the PTR family, no peptide transport activity was observed when OsNRT1 was expressed in either Xenopus oocytes or yeast. Furthermore, contrasting the dual-affinity nitrate transport activity of CHL1, OsNRT1 displayed only low-affinity nitrate transport activity in Xenopus oocytes, with a K(m) value of approximately 9 mM. Northern-blot and in situ hybridization analysis indicated that OsNRT1 is constitutively expressed in the most external layer of the root, epidermis and root hair. These data strongly indicate that OsNRT1 encodes a constitutive component of a low-affinity nitrate uptake system for rice.

Bactericidal activity of isothiocyanate against pathogens on fresh produce

The bactericidal activity of allyl and methyl isothiocyanate (AITC and MITC) was tested with a rifampicin-resistant strain of Salmonella Montevideo and streptomycin-resistant strains of Escherichia coil O157:H7 and Listeria monocytogenes Scott A. Iceberg lettuce inoculated with high (10(7) to 10(8) CFU/g) and low (10(3) to 10(4) CFU/g) concentrations of bacterial pathogens was treated with AITC and MITC in sealed containers at 4 degrees C for 4 days. AITC showed stronger bactericidal activity than MITC against E. coli O157:H7 and Salmonella Montevideo, whereas MITC showed stronger activity against L. monocytogenes than E. coli O157:H7 and Salmonella Montevideo. Up to 8-log reduction occurred with E. coli O157:H7 and Salmonella Montevideo on lettuce following treatment with vapor generated from 400 microl of AITC for 2 and 4 days, respectively. AITC was used to treat tomatoes inoculated with Salmonella Montevideo on stem scars and skin and apples inoculated with E. coli O157:H7 on stem scars. The bactericidal effect of AITC varied with bacteria species and exposure time. Salmonella Montevideo inoculated on tomato skin was more sensitive to AITC than that on stem scars. Treatment with vapor generated from 500 microl of AITC caused an 8-log reduction in bacteria on tomato skin but only a 5-log reduction on tomato stem scars. The bactericidal activity of AITC was weaker for E. coli O157:H7 on apple stem scars; only a 3-log reduction in bacteria occurred when 600 microl of AITC was used.

Mouse endostatin inhibits the formation of lung and liver metastases

Angiogenesis is required for tumor formation. Several studies have demonstrated that tumor angiogenesis is regulated by a balance between proangiogenesis and antiangiogenesis factors and that this balance varies in different organ environments. To investigate whether expression of an angiogenesis inhibitor by cancer cells could alter this balance and prevent tumor formation in different organ environments, we engineered stable transfectants from RenCa mouse renal carcinoma cells and SW620 human colon carcinoma cells to constitutively secrete a mouse endostatin protein with c-myc and polyhistidine (His) tags. Production and secretion of the endostatin-c-myc-His fusion protein by endostatin-transfected cells were confirmed by immunofluorescence staining and Western blot analysis. The endostatin transfectants and control transfectants, stably transfected with a control plasmid, had similar in vitro growth rates compared with their parental cell lines. Conditioned medium from endostatin-transfected cells inhibited human umbilical vein endothelial cell proliferation by 36-51% compared with conditioned medium from control cells. After inoculation into mice, flank tumors from endostatin-transfected cells were 73-91% smaller than flank tumors from control cells after 3 weeks. Inoculation of a cell mixture containing 25% endostatin-transfected cells and 75% control cells resulted in inhibition of flank tumor formation as effective as after inoculation of 100% endostatin-transfected cells. Formation of lung metastases by RenCa endostatin-transfected cells and formation of liver metastases by SW620 endostatin-transfected cells were dramatically inhibited compared with formation of metastases by control cells. These findings demonstrate that endostatin can inhibit tumor formation in different organ environments and that gene delivery of endostatin into even a minority of tumor cells may be an effective strategy to prevent progression of micrometastases to macroscopic disease.

Towards metabolic sink therapy for mut methylmalonic acidaemia: correction of methylmalonyl-CoA mutase deficiency in T lymphocytes from a mut methylmalonic acidaemia child by retroviral-mediated gene transfer

The pathology associated with mut methylmalonic acidaemia (MMA) is caused by systemic accumulation of methylmalonate. Therefore, removal of methylmalonate from the circulation of affected individuals by an engineered metabolic system is proposed as a potential treatment. The haematopoietic cell is a potential site for such a metabolic system because of its direct contact with the accumulated metabolite and the demonstrated safety and ease in utilizing this cell. In this study, we assessed the feasibility of developing a haematopoietic cell-based methylmalonate sink by analysing propionate/methylmalonate metabolism in a variety of haematopoietic cells. The results show that propionate metabolism and methylmalonyl-CoA mutase (MCM) activity are intact in primary T cells, EBV-B cells, and CD34+ haematopoietic stem cell-derived granulocytes, whereas they are defective in those from a mut MMA child. Moreover, normal T and EBV-B cells clear methylmalonate from the medium at a significant rate. Transduction of MCM-deficient T cells with a recombinant retrovirus encoding the human MCM cDNA results in correction of propionate metabolism. These results establish the basis for developing haematopoietic cell-based metabolic sink therapy for mut MMA by T lymphocyte/haematopoietic stem cell-directed gene transfer.