Chronic Gut Inflammation and Dysbiosis in IBS: Unraveling Their Contribution to Atopic Dermatitis Progression

Emerging evidence suggests a link between atopic dermatitis (AD) and gastrointestinal disorders, particularly in relation to gut microbial dysbiosis. This study explored the potential exacerbation of AD by gut inflammation and microbial imbalances using an irritable bowel syndrome (IBS) mouse model. Chronic gut inflammation was induced in the model by intrarectal injection of 2,4,6-trinitrobenzene sulfonic acid (TNBS), followed by a 4-week development period. We noted significant upregulation of proinflammatory cytokines in the colon and evident gut microbial dysbiosis in the IBS mice. Additionally, these mice exhibited impaired gut barrier function, increased permeability, and elevated systemic inflammation markers such as IL-6 and LPS. A subsequent MC903 challenge on the right cheek lasting for 7 days revealed more severe AD symptoms in IBS mice compared to controls. Further, fecal microbial transplantation (FMT) from IBS mice resulted in aggravated AD symptoms, a result similarly observed with FMT from an IBS patient. Notably, an increased abundance of Alistipes in the feces of IBS mice correlated with heightened systemic and localized inflammation in both the gut and skin. These findings collectively indicate that chronic gut inflammation and microbial dysbiosis in IBS are critical factors exacerbating AD, highlighting the integral relationship between gut and skin health.

Potential role of acupuncture in the treatment of Parkinson's disease: A narrative review

Background

The prevalence of Parkinson's disease (PD) has grown rapidly compared to that of other neurological disorders. Acupuncture has been used to address the complex symptoms of PD. Recently, similarities in the mechanisms of action between acupuncture and neuromodulation have received considerable attention. This review aims to summarize the evidence regarding these similarities to suggest potential role of acupuncture in the treatment of PD.

Methods

The literature from two electronic databases, PubMed and Google Scholar, was searched using the search terms 'Acupuncture', 'Parkinson's disease', 'Vagus nerve stimulation', and 'Brain functional connectivity'. We then explored the evidence for the effectiveness of acupuncture in PD and evaluated the evidence for similarities in the mechanisms of action between acupuncture and neuromodulation.

Results

Data suggests that acupuncture treatment is effective for PD symptoms by modulating inflammation and brain functional connectivity (BFC). These acupuncture effects have been shown to be similar to neuromodulation in controlling inflammation and BFC. Based on the shared mechanisms of action, potential acupuncture mechanisms that may ameliorate a wide range of PD symptoms include but are not limited to (1) vagal activation of the anti-inflammatory pathway and (2) BFC enhancement.

Conclusion

The development of acupuncture strategies based on shared mechanisms with neuromodulation will provide new treatment options for patients with PD as personalized neuromodulating therapies. Further studies are needed to gather scientific evidence for optimizing parameters in PD patients.

Acupuncture Regulates Symptoms of Parkinson’s Disease via Brain Neural Activity and Functional Connectivity in Mice

Parkinson’s disease (PD) is a multilayered progressive brain disease characterized by motor dysfunction and a variety of other symptoms. Although acupuncture has been used to ameliorate various symptoms of neurodegenerative disorders, including PD, the underlying mechanisms are unclear. Here, we investigated the mechanism of acupuncture by revealing the effects of acupuncture treatment on brain neural responses and its functional connectivity in an animal model of PD. We observed that destruction of neuronal network between many brain regions in PD mice were reversed by acupuncture. Using machine learning analysis, we found that the key region associated with the improvement of abnormal behaviors might be related to the neural activity of M1, suggesting that the changes of c-Fos in M1 could predict the improvement of motor function induced by acupuncture treatment. In addition, acupuncture treatment was shown to significantly normalize the brain neural activity not only in M1 but also in other brain regions related to motor behavior (striatum, substantia nigra pars compacta, and globus pallidus) and non-motor symptoms (hippocampus, lateral hypothalamus, and solitary tract) of PD. Taken together, our results demonstrate that acupuncture treatment might improve the PD symptoms by normalizing the brain functional connectivity in PD mice model and provide new insights that enhance our current understanding of acupuncture mechanisms for non-motor symptoms.

The Role of Skin Mast Cells in Acupuncture Induced Analgesia in Animals: A Preclinical Systematic Review and Meta-analysis

While mast cells (MCs) are previously well-known as a pathological indicator of pain, their role in alleviating pain is recently emerged in acupuncture research. Thus, this study systematically reviews the role of MC in acupuncture analgesia. Animal studies on MC changes associated with the acupuncture analgesia were searched in PubMed and EMBASE. The MC number, degranulation ratio and pain threshold changes were collected as outcome measures for meta-analyses. Twenty studies were included with 13 suitable for meta-analysis, most with a moderate risk of bias. A significant MC degranulation after acupuncture was indicated in the normal and was significantly higher in the pain model. In the subgroup analysis by acupuncture type, manual (MA) and electrical (EA, each P < .00001) but not sham acupuncture had significant MC degranulation. Meta-regression revealed the linear proportionality between MC degranulation and acupuncture-induced analgesia (P < .001), which was found essential in MA (P < .00001), but not in EA (P = .45). MC mediators, such as adenosine and histamine, are involved in its mechanism. Taken together, skin MC is an essential factor for acupuncture-induced analgesia, which reveals a new aspect of MC as a pain alleviator. However, its molecular mechanism requires further study. PERSPECTIVE: This systematic review synthesizes data from studies that examined the contribution of skin MC in acupuncture analgesia. Current reports suggest a new role for skin MC and its mediators in pain alleviation and explain a peripheral mechanism of acupuncture analgesia, with suggesting the need of further studies to confirm these findings.

Intranasal Administration of Melanin-Concentrating Hormone Reduces Stress-Induced Anxiety- and Depressive-Like Behaviors in Rodents

Major depressive disorder is a complex neuropsychiatric disorder with few treatment options. Non-targeted antidepressants have low efficacy and can induce series of side effects. While a neuropeptide, melanin-concentrating hormone (MCH), is known to exhibit regulator of affective state, no study to date has assessed the anti-depressive effects of MCH in a stress-induced depression model. This study aimed to evaluate the pharmacological effects of intranasal administration of MCH on depression-related behavior in stressed rats and mice. Using a number of behavioral tests, we found that MCH treatment significantly decreased anxiety- and depressive-like behaviors induced by stress. Notably, the effects of MCH were equivalent to those of fluoxetine. MCH treatment also restored the activity of the mammalian target of rapamycin (mTOR) signaling pathway and normalized the levels of synaptic proteins, including postsynaptic density 95, glutamate receptor 1, and synapsin 1, which were all downregulated by stress. Interestingly, the protective effects of MCH were blocked by the mTOR inhibitor, rapamycin. These results suggest that MCH exhibits antidepressant properties by modulating the mTOR pathway. Altogether, this study provides an insight into the molecular mechanisms involved in the antidepressant-like effects of MCH, thereby paving the way for the future clinical application of MCH.

Strong correlation between flux pinning and epitaxial strain in the GdBa2Cu3O7-x /La0.7Sr0.3MnO3 nanocrystalline heterostructure

The effect of magnetic flux pinning is investigated in GdBa₂Cu₃O₇ (GdBCO) thin films with two different types of ferromagnetic La_0.7Sr_0.3MnO₃ (LSMO) buffers (nanoparticles and a layer) deposited on an STO substrate. Magnetization analyses reveal the presence of multiple flux pinning mechanisms responsible for the improvement in the critical current density of GdBCO films. While core pinning becomes a dominant pinning mechanism in GdBCO films with LSMO nanoparticles, a hybrid effect of magnetic-volume and core-point pinning is observed in GdBCO films with LSMO layers. Examinations of local structures for both LSMO and GdBCO using extended X-ray absorption fine structure spectroscopy (EXAFS) exhibit a close relation between the parameters in the pinning force scaling and the length ratio of the Mn–O bond to the Cu–O bond. This result implies that the origin of core pinning is probably attributed to epitaxial strain induced by lattice mismatch between LSMO and GdBCO. Therefore, an appropriate strain state of LSMO is required for an effective operation of magnetic pinning.

The effect of magnetic flux pinning is investigated in GdBa₂Cu₃O₇ (GdBCO) thin films with two different types of ferromagnetic La_0.7Sr_0.3MnO₃ (LSMO) buffers (nanoparticles and a layer) deposited on an STO substrate.

Acupuncture inhibits neuroinflammation and gut microbial dysbiosis in a mouse model of Parkinson's disease

Growing evidences show that gut microbiota is associated with the pathogenesis of Parkinson's disease (PD) and the gut-brain axis can be promising target for the development of the therapeutic strategies for PD. Acupuncture has been used to improve brain functions and inflammation in neurological disorders such as PD, and to recover the gastrointestinal dysfunctions in various gastrointestinal disorders. Thus, we investigated whether acupuncture could improve Parkinsonism and gut microbial dysbiosis induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. First, we observed that acupuncture treatment at acupoints GB34 and ST36 could improve motor functions and comorbid anxiety in PD mice. Next, we found that acupuncture increased the levels of dopaminergic fibers and neurons in the striatum and the substantia nigra, respectively. Acupuncture also restored the overexpression of microglia and astrocyte as well as conversion of Bax and Bcl-2 expression in both the striatum and the substantia nigra, indicating that inflammatory responses and apoptosis were blocked by acupuncture. Additionally, via 16S rRNA sequence analysis, we observed that the relative abundance of 18 genera were changed in acupuncture-treated mice compared to the PD mice. Of them, Butyricimonas, Holdemania, Frisingicoccus, Gracilibacter, Phocea, and Aestuariispira showed significant correlations with anxiety as well as motor functions. Furthermore, the predicted functional analyses showed that acupuncture restored the physiology functions such as glutathione metabolism, methane metabolism, and PD pathway. In conclusion, we suggest that the effects of acupuncture on the enhanced motor function and the protection of the dopaminergic neurons may be associated with the regulation of the gut microbial dysbiosis and thus the inhibition of the neuroinflammation in the PD mice.

Muscovite nanoparticles mitigate neuropathic pain by modulating the inflammatory response and neuroglial activation in the spinal cord

Despite numerous efforts to overcome neuropathic pain, various pharmacological drugs often fail to meet the needs and have many side effects. Muscovite is an aluminosilicate mineral that has been reported to have an anti-inflammatory effect, but the efficacy of muscovite for neuropathic pain has not been investigated. Here, we assessed whether muscovite nanoparticles can reduce the symptoms of pain by controlling the inflammatory process observed in neuropathic pain. The analgesic effects of muscovite nanoparticles were explored using partial sciatic nerve ligation model of neuropathic pain, in which one-third to one-half of the nerve trifurcation of the sciatic nerve was tightly tied to the dorsal side. Muscovite nanoparticles (4 mg/100 μL) was given intramuscularly to evaluate its effects on neuropathic pain (3 days per week for 4 weeks). The results showed that the muscovite nanoparticle injections significantly alleviated partial sciatic nerve ligation-induced mechanical and cold allodynia. In the spinal cord, the muscovite nanoparticle injections exhibited inhibitory effects on astrocyte and microglia activation and reduced the expression of pro-inflammatory cytokines, such as interleukin-1β, tumor necrosis factor-α, interleiukin-6 and monocyte chemoattractant protein-1, which were upregulated in the partial sciatic nerve ligation model. Moreover, the muscovite nanoparticle injections resulted in a decrease in activating transcription factor 3, a neuronal injury marker, in the sciatic nerve. These results suggest that the analgesic effects of muscovite nanoparticle on partial sciatic nerve ligation-induced neuropathic pain may result from inhibiting activation of astrocytes and microglia as well as pro-inflammatory cytokines. We propose that muscovite nanoparticle is a potential anti-nociceptive candidate for neuropathic pain. All experimental protocols in this study were approved by the Institutional Animal Ethics Committee (IACUC) at Dongguk University, South Korea (approval No. 2017-022-1) on September 28, 2017.

Prone positioning before extracorporeal membrane oxygenation for severe acute respiratory distress syndrome: A retrospective multicenter study

OBJECTIVE

To evaluate the clinical outcomes of patients with severe acute respiratory distress syndrome (ARDS) subjected to prone positioning before extracorporeal membrane oxygenation (ECMO).

DESIGN

A retrospective analysis of a multicenter cohort was carried out.

SETTING

Patients admitted to the Intensive Care Units of 11 hospitals in Korea.

PATIENTS

Patients were divided into those who underwent prone positioning before ECMO (n=28) and those who did not (n=34).

INTERVENTIONS

None.

VARIABLES OF INTEREST

Thirty-day mortality, ECMO weaning failure rate, mechanical ventilation weaning success rate, mechanical ventilation-free days at day 60.

RESULTS

The prone group had lower median peak inspiratory pressure and lower median dynamic driving pressure before ECMO. Thirty-day mortality was 21% in the prone group and 41% in the non-prone group (p=0.098). The prone group also showed a lower ECMO weaning failure rate, and a higher mechanical ventilation weaning success rate and more mechanical ventilation-free days at day 60. In the non-prone group, median dynamic compliance marginally decreased shortly after ECMO, but no significant change was observed in the prone group.

CONCLUSIONS

Prone positioning before ECMO was not associated to increased mortality and tended to exert a protective effect.

Acupuncture Improves Comorbid Cognitive Impairments Induced by Neuropathic Pain in Mice

Growing evidence indicates that neuropathic pain is frequently accompanied by cognitive impairments, which aggravate the quality of life of chronic pain patients. Here, we investigated whether acupuncture treatments can improve cognitive dysfunction as well as allodynia induced by neuropathic pain in mice. One week after the left partial sciatic nerve ligation (PSNL), acupuncture treatments on the acupoints GB30-GB34 (AP1), HT7-GV20 (AP2), or control points (CP) were performed for 4 weeks. Notably, the significant attenuations of mechanical allodynia and cognitive impairment were observed in the AP1 group, but not in PSNL, AP2, or CP groups. A random decision forest classifier based on the pain and cognitive functions displayed that the acupuncture group was clearly segregated from the other groups. We also demonstrated that acupuncture restored the reduced field excitatory post-synaptic potentials and was able to elevate the expression levels of glutamate receptors (NR2B and GluR1) in the hippocampus. Moreover, the expressions of Ca²⁺/calmodulin-dependent protein kinase II and synaptic proteins (pPSD-95 and pSyn-1) were enhanced by acupuncture treatment. These results suggest that acupuncture can enhance hippocampal long-term action through the regulation of the synaptic efficacy and that acupuncture may provide a viable option for managing both pain and cognitive functions associated with chronic neuropathic pain.

Augmented Mechanical Forces of the Surface-Modified Nanoporous Acupuncture Needles Elicit Enhanced Analgesic Effects

Over the past several decades, clinical studies have shown significant analgesic effects of acupuncture. The efficacy of acupuncture treatment has improved with the recent development of nanoporous needles (PN), which are produced by modifying the needle surface using nanotechnology. Herein, we showed that PN at acupoint ST36 produces prolonged analgesic effects in an inflammatory pain model; the analgesic effects of PN acupuncture were sustained over 2 h, while those using a conventional needle (CN) lasted only 30 min. In addition, the PN showed greater therapeutic effects than CN after 10 acupuncture treatments once per day for 10 days. We explored how the porous surface of the PN contributes to changes in local tissue, which may in turn result in enhanced analgesic effects. We showed that the PN has greater rotational torque and pulling force than the CN, particularly at acupoints ST36 and LI11, situated on thick muscle layers. Additionally, in ex vivo experiments, the PN showed greater winding of subcutaneous connective tissues and muscle layers. Our results suggest that local mechanical forces are augmented by the PN and its nanoporous surface, contributing to the enhanced and prolonged analgesic effects of PN acupuncture.

Acupuncture modulates stress response by the mTOR signaling pathway in a rat post-traumatic stress disorder model

Post-traumatic stress disorder (PTSD) is a psychiatric disease that can form following exposure to a traumatic event. Acupuncture has been proposed as a beneficial treatment for PTSD, but the underlying mechanisms remain unclear. The present study investigated whether acupuncture improves depression- and anxiety-like behaviors induced using a single prolonged stress (SPS) as a PTSD rat model. In addition, we investigated whether the effects were mediated by increased mTOR activity and its downstream signaling components, which contribute to protein synthesis required for synaptic plasticity in the hippocampus. We found that acupuncture at HT8 significantly alleviated both depression- and anxiety-like behaviors induced by SPS in rats, as assessed by the forced swimming, elevated plus maze, and open field tests; this alleviation was blocked by rapamycin. The effects of acupuncture were equivalent to those exerted by fluoxetine. Acupuncture regulated protein translation in the mTOR signaling pathway and enhanced the activation of synaptic proteins, PSD95, Syn1, and GluR1 in the hippocampus. These results suggest that acupuncture exerts antidepressant and anxiolytic effects on PTSD-related symptoms by increasing protein synthesis required for synaptic plasticity via the mTOR pathway in the hippocampus. Acupuncture may be a promising treatment for patients with PTSD and play a role as an alternative PTSD treatment.

Prone positioning before extracorporeal membrane oxygenation for severe acute respiratory distress syndrome: A retrospective multicenter study

OBJECTIVE

To evaluate the clinical outcomes of patients with severe acute respiratory distress syndrome (ARDS) subjected to prone positioning before extracorporeal membrane oxygenation (ECMO).

DESIGN

A retrospective analysis of a multicenter cohort was carried out.

SETTING

Patients admitted to the Intensive Care Units of 11 hospitals in Korea.

PATIENTS

Patients were divided into those who underwent prone positioning before ECMO (n=28) and those who did not (n=34).

INTERVENTIONS

None.

VARIABLES OF INTEREST

Thirty-day mortality, ECMO weaning failure rate, mechanical ventilation weaning success rate, mechanical ventilation-free days at day 60.

RESULTS

The prone group had lower median peak inspiratory pressure and lower median dynamic driving pressure before ECMO. Thirty-day mortality was 21% in the prone group and 41% in the non-prone group (p=0.098). The prone group also showed a lower ECMO weaning failure rate, and a higher mechanical ventilation weaning success rate and more mechanical ventilation-free days at day 60. In the non-prone group, median dynamic compliance marginally decreased shortly after ECMO, but no significant change was observed in the prone group.

CONCLUSIONS

Prone positioning before ECMO was not associated to increased mortality and tended to exert a protective effect.

What intrinsic factors influence responsiveness to acupuncture in pain?: a review of pre-clinical studies that used responder analysis

BACKGROUND

Not many studies have investigated individual sensitivity to acupuncture. To explore the intrinsic factors related to individual responses to acupuncture, we reviewed published pre-clinical studies using responder analysis on pain.

METHODS

We searched the PubMed and EMBASE databases to June 2015. We included pre-clinical reports describing responders and non-responders to anti-nociceptive and analgesic effects of acupuncture in animal study. We identified the potential intrinsic factors which might be related with the response to acupuncture.

RESULTS

Totally, 216 potentially relevant articles were retrieved and 14 studies met our inclusion criteria. Rat (n = 1348) and rabbit (n = 56) were used, and only electroacupuncture (EA) was applied as an intervention. Results showed that high levels of cholecystokinin-8 and receptors were associated with poor responsiveness to EA. Endogenous opioids including β-endorphin and met-enkephalin, descending inhibitory norepinephrine and serotonin system, and hypothalamic 5'-AMP-activated protein kinase seemed to be associated with high-level responses. Spinal levels of neurotransmitters and pro-inflammatory cytokines were also differentially expressed depending on the EA sensitiveness. In the central nervous system, hypothalamus, periaqueductal grey, pituitary gland, and spinal cord were suggested to be involved in the EA responsiveness. Identified individual variations did not seem to be accidental, as the responsiveness to EA was replicated over time. However, methodological issues such as reproducibility, cut-off criteria, and clinical relevance need to be further elaborated.

CONCLUSION

Our study suggests that the identification of the biological factors differentiating responders from non-responders is necessary and it may aid in understanding how acupuncture modulates pain.

Association between interleukin-27 polymorphisms and pulmonary tuberculosis

OBJECTIVE

To investigate the effect of interleukin (IL) 27 -964A/G, 2095T/G, 4603G/A and 4730T/C gene polymorphisms on the development of pulmonary tuberculosis (PTB), radiographic characteristics and severity.

DESIGN

Differences in the allele and genotype distributions of the -964A/G, 2095T/G, 4603G/A and 4730T/C polymorphisms between 224 PTB patients and 233 healthy controls, between patients with single- and multi-lobe involvement, and between patients with and without cavitation, were investigated. Serum IL-27 concentration was measured using an enzyme-linked immunosorbent assay.

RESULTS

There were no significant differences in the allele or genotype distributions between PTB patients and healthy controls. However, the -964A/A genotype was more prevalent in patients with single-lobe involvement than the -964A/G or -964G/G genotype in patients with multi-lobe involvement (50.0% vs. 31.3%, P = 0.01). There was no difference between patients with and without cavitation (P > 0.05). Serum median IL-27 concentration was significantly higher in patients with single-lobe involvement than in those with multi-lobe involvement (P = 0.03) and in those with -964A/A genotypes than in those with -964A/G or -964G/G genotypes (P = 0.02).

CONCLUSIONS

In terms of serum IL-27 levels, the -964 A/A genotype may be associated with a protective role that prevents the intrapulmonary spread of PTB rather than its development.

The embryo lethality of Escherichia coli isolates and its relationship to the presence of virulence-associated genes

The aims of this study were to determine if the chicken embryo lethality assay and the presence of 9 virulence-associated genes of Escherichia coli were correlated and to discover which virulence genes contributed most to embryo lethality. We examined 58 E. coli strains isolated from visceral organs of chickens with colibacillosis for the presence of 9 virulence genes (fimC, tsh, fyuA, irp2, iucD, cvi/cva, iss, astA, and vat) by PCR. The gene FimC (type I fimbriae) was detected with the highest prevalence in 93.1% of the isolates, followed by iucD (67.24%), iss (58.62%), tsh (34.48%), cvi/cva (34.48%), fyuA (32.76%), astA (31.0%), irp2 (27.59%), and vat (17.24%). The embryo mortality ranged from 5 to 100%; however, most of the isolates were moderately or highly virulent. High positive correlations were observed between the presence of virulence genes and chicken embryo lethality. In addition, presence of the iucD (aerobactin) gene was the trait that best contributed to embryo mortality by using the multivariate model. These results suggest that expression frequency of these 9 virulence genes is associated with embryo mortality, and the gene that best predicted embryo mortality was iucD.

Characterization of Escherichia coli isolates from laying hens with colibacillosis on 2 commercial egg-producing farms in Korea

The present study reports on layer chickens with colibacillosis in 2 commercial egg-producing farms (referred to as farm A and farm B, which were managed by the same owner and were about 1 km apart) in the middle region of the Korean peninsula. The 2 flocks were infected at the initiation of egg laying. They were characterized by no previous clinical signs but sudden mortality (2.7-4.0%), with severe lesions of septicemia and fibrinous polyserositis. Escherichia coli was isolated from the lesions of the infected birds. Serotyping tests identified isolates that belonged to somatic groups O1 (12/17), O46 (2/17), O78 (1/17), and O84 (1/17) or that were unidentified (1/17). Thirteen of 17 E. coli isolates (76.4%) obtained from 11 birds in the 2 flocks showed similar pulsed-field gel electrophoresis patterns that were arbitrarily designated as pattern A. The isolates had high frequencies of putative virulence genes including 100% [fimC (type 1 fimbriae), iucD (aerobactin synthesis), and iss (increased serum survival)], 94.1% [cva/cvi (structural genes of colicin V operon) and vat (vacuolating autotransporter toxin)], 88.2% [irp2, iron-repressible protein (yersinia bactin) synthesis, and fyuA, ferric yersinia uptake], and 82.3% [tsh (temperature-sensitive hemagglutinin)]; astA (encoding a heat-stable cytotoxin associated with enteroaggregative E. coli) was not associated with the enteric disorder. These data suggest that all chickens with colibacillosis on farms A and B were likely infected by E. coli strains that are highly pathogenic in avian species.

A Selective Encryption Algorithm Based on AES for Medical Information

OBJECTIVES

The transmission of medical information is currently a daily routine. Medical information needs efficient, robust and secure encryption modes, but cryptography is primarily a computationally intensive process. Towards this direction, we design a selective encryption scheme for critical data transmission.

METHODS

We expand the advandced encrytion stanard (AES)-Rijndael with five criteria: the first is the compression of plain data, the second is the variable size of the block, the third is the selectable round, the fourth is the optimization of software implementation and the fifth is the selective function of the whole routine. We have tested our selective encryption scheme by C(++) and it was compiled with Code::Blocks using a MinGW GCC compiler.

RESULTS

The experimental results showed that our selective encryption scheme achieves a faster execution speed of encryption/decryption. In future work, we intend to use resource optimization to enhance the round operations, such as SubByte/InvSubByte, by exploiting similarities between encryption and decryption.

CONCLUSIONS

As encryption schemes become more widely used, the concept of hardware and software co-design is also a growing new area of interest.

Susceptibility of porcine keratocytes to immune-mediated damage in xeno-related rejection

We admixed cultured porcine keratocytes or corneal endothelial cells in the presence of human sera or peripheral blood mononuclear cells (PBMCs) for 4 to 72 hours to investigate their immune-related susceptibilities to xeno-related rejection. We evaluated complement deposition at 48 hours by flow cytometry after staining with the C3 anti-goat cy3 antibody. The inhibition of proliferation of porcine corneal cells by human sera was examined using the 3-[4,5-dimethy/thiazol-2,5-dephenyl tetrazolium bromide (MTT) assay over 24 to 72 hours. The amount of 51chromium (Cr)-release was estimated after a reaction between the porcine cells and human PBMCs for 4 hours. There was greater C3 deposition in keratocytes (60.2%) than in endothelial cells (26.9%; P = .05, Mann-Whitney U test). Both keratocytes and endothelial cells showed significant levels of proliferative inhibition over a period of 72 hours. The number of 51Cr-release cells on interleukin-2 addition was significantly higher among keratocytes (88.0%) than endothelial cells (51.4%) at a 1:100 target:effector ratio (P = .04, Mann-Whitney U test). Our present data suggested that porcine keratocytes might be key target cells in xeno-related rejections when the porcine cornea is transplanted to primates.

Systemic armed oncolytic and immunologic therapy for cancer with JX-594, a targeted poxvirus expressing GM-CSF

Targeted oncolytic viruses and immunostimulatory therapeutics are being developed as novel cancer treatment platforms. These approaches can be combined through the expression of immunostimulatory cytokines from targeted viruses, including adenoviruses and herpesviruses. Although intratumoral injection of such viruses has been associated with tumor growth inhibition, eradication of distant metastases was not reported. The major limitations for this approach to date have been (1) inefficient intravenous virus delivery to tumors and (2) the lack of predictive, immunocompetent preclinical models. To overcome these hurdles, we developed JX-594, a targeted, thymidine kinase(-) vaccinia virus expressing human GM-CSF (hGM-CSF), for intravenous (i.v.) delivery. We evaluated two immunocompetent liver tumor models: a rabbit model with reproducible, time-dependent metastases to the lungs and a carcinogen-induced rat liver cancer model. Intravenous JX-594 was well tolerated and had highly significant efficacy, including complete responses, against intrahepatic primary tumors in both models. In addition, whereas lung metastases developed in all control rabbits, none of the i.v. JX-594-treated rabbits developed detectable metastases. Tumor-specific virus replication and gene expression, systemically detectable levels of hGM-CSF, and tumor-infiltrating CTLs were also demonstrated. JX-594 holds promise as an i.v.-delivered, targeted virotherapeutic. These two tumor models hold promise for the optimization of this approach.

Short-term effect of intracameral triamcinolone acetonide on corneal endothelium using the rabbit model

PURPOSE

To investigate the effect of intracameral injection of triamcinolone acetonide on the corneal endothelium in rabbit eyes.

METHODS

Triamcinolone acetonide (40 mg/ml, 0.2 cm3) after filtering and resuspension in balanced salt solution (BSS) was injected intracamerally for 3 min into 10 rabbit eyes and irrigated with 5 cm(3) of BSS. Triamcinolone without resuspension and BSS were injected, respectively, into five rabbit eyes. Endothelial toxicity was evaluated and compared by measurements of endothelial cell counts and central corneal thickness. The endothelial viability was determined using vital staining with alizarin red and trypan blue at 2 h after injection. The scanning electron microscopy (SEM) was performed in one cornea from each group.

RESULTS

Endothelial cell counts and central corneal thickness following intracameral injection of triamcinolone acetonide did not significantly change when compared to controls. The mean percentage of viable endothelial cells was 99.50, 99.52, and 99.49% in the resuspended triamcinolone group, triamcinolone without resuspension group, and BSS group, respectively (P=0.46, Kruskall-Wallis test). But SEM showed reduced microvilli of endothelial surface in an eye of the triamcinolone without resuspension group.

CONCLUSIONS

The intracameral injection of triamcinolone acetonide did not induce a significant visible change of endothelium in rabbit eyes. However, ultrastructural villi changes observed suggest a possibility of microstructural damages in endothelium with triamcinolone acetonide injection when used without filtering and resuspension.

Survival analysis of 365 patients with exotropia after surgery

PURPOSE

Few reports have included large numbers of exotropia patients. Thus, we undertook this study to perform a survival analysis of over 350 patients with exotropia and to determine which factors might affect the outcome of exotropia surgery.

METHODS

The clinical records of 365 patients who underwent exotropia surgery by one surgeon were retrospectively reviewed. Preoperative patient characteristics, surgical procedures performed, and early postoperative ocular alignment were evaluated as potential risk factors of surgical outcome using survival analysis.

RESULTS

The estimated median time from surgery to recurrence was 48.3 months. None of the characteristics or procedures were found to be significantly associated with surgical outcome. The likelihood of a good postoperative surgical outcome was highest with an initial postoperative alignment of more than 10 prism diopters of esotropia (P<0.001).

CONCLUSIONS

Early postoperative overcorrection was the only predictor of a successful long-term outcome after exotropia surgery.

Purification and characterization of a new anticoagulant protein, PP27, from placenta

It has long been known that water extracts of placenta hominis (Jahage in Korean) are effective for treating immunological and vascular diseases and is a major constituent of traditional oriental medicines. We report herein on the isolation and purification of a new type of anticoagulant protein, PP27, from human placenta. PP27 ran as a single band on SDS-PAGE with a molecular mass (Mr) of 27 kDa under denaturing conditions and chromatography on a calibrated Sepharose 4B column indicated a molecular mass of 23 kDa, a value that is similar to those of other PP4 enzymes reported to date. The isoelectric point of PP27 was pI 5.2. PP27, at doses higher than 10 microg/ml, inhibited platelet activating factor (PAF)-induced platelet activation in a dose-dependent manner. The protein was found to inhibit the coagulation time in a concentration-dependent manner. PP27, which acts as a vascular anticoagulant of annexin type, inhibits the blood clotting process by virtue of its binding of essential lipids, which is dependent on the presence of Ca2+ ions. In the presence of Ca2+ ions, PP27 combines with platelet membranes and neutralizes their procoagulant effect. Coagulation, triggered by the addition of thromboplastin/lipid mixtures, is extinguished by PP27.

Response of pulmonary tuberculomas to anti-tuberculous treatment

Pulmonary tuberculomas are well-circumscribed masses caused by Mycobacterium tuberculosis. However, the response of tuberculomas to anti-tuberculous (TB) treatment has not been well defined as yet. The response of pulmonary tuberculomas to anti-TB treatment was retrospectively reviewed in 45 patients diagnosed between January 1997 and December 2001. The areas of pulmonary tuberculomas were estimated by calculating products of the longest and their perpendicular short diameters on chest radiographs. The response to anti-TB treatment was categorised as "decreased" (> 25% reduction in area versus its initial area), "increased" (> 251% increase) and "no change" (the remainder). The mean of treatment duration was 11.5 +/- 3.6 months. Three months after treatment, 18 patients (40.0%) were categorised as decreased, 25 (55.6%) as no change and two (4.4%) as increased. Twelve months after treatment, out of 42 patients available for chest radiographs, 32 patients (76.2%) were categorised as decreased, nine (21.4%) as no change and one patient (2.4%) as increased. At the last follow-up (mean follow-up 27.0 +/- 10.2 months), 37 patients (82.2%) were categorised as decreased. The majority of pulmonary tuberculomas were decreased by anti-tuberculosis treatment during and even after treatment, although a transient enlargement during the early period of treatment was observed infrequently.

Antibiotic selective pressure for the maintenance of antibiotic resistant genes in coliform bacteria isolated from the aquatic environment

Coliform bacteria isolated from the aquatic environment were investigated for antibiotic susceptibility and detailed structures of class 1 integrons. A high proportion of isolates were found to be resistant to sulfamethoxazole, aminoglycosides, and beta-lactams. The 750 (53.6%) isolates were resistant to one or more of the antibiotics tested out of 1,400 coliform bacteria. Based on the MIC of antibiotics and antibiogram, 150 isolates were selected and further studied for class 1 integrons. The intI1 gene was found in 36 (24.0%) of the 150 isolates. Twelve isolates carried the gene cassettes responsible for antibiotic resistance, while no gene cassettes were found in 24 isolates. Seven different genes, dfrA5, dfrA7, dfrA12, dfrA17, aaA2, aaA5, and aad(3'), were detected in gene cassettes. The dfrA and aad genes located on class 1 integrons were responsible for resistance to trimethoprim and aminoglycosides. The remaining 24 coliform bacteria had the incomplete or non-functional class 1 integrons. These results indicated that antibiotic selective pressures may play an important role to maintain gene cassettes of class 1 integrons and in the absence of sustained antibiotic pressures, such as the aquatic environment, coliform bacteria may carry empty or non-functional class 1 integrons.

p21(WAF1) is associated with CDK2 and CDK4 protein during HL-60 cell differentiation by TPA treatment

TPA-treated HL-60 cells are mainly arrested in G1 by p21(WAF1) accumulation. We investigate the downstream changes following such accumulation. Increased p21(WAF1) is associated with CDK2 and CDK4. pRb is dephosphorylated in the presence of p21-CDK2/4 complexes, and the Rb-E2F1 complex increases after TPA treatment, whereas the Rb-HDAC1 complex decreases slightly. Our results suggest that increased p21(WAF1) is associated with CDK2/4, and that these complexes induce pRb dephosphorylation. In turn, hypophosphorylated pRb are mainly complexed with E2F1, but HDAC1 appears not to be a key component in this process.

Enhancement of phospholipase D activity by overexpression of amyloid precursor protein in P19 mouse embryonic carcinoma cells

It has been shown that phospholipase D (PLD) activity is stimulated by the beta-amyloid protein in neuronal cells. The aim of this study was to determine whether overexpression of the amyloid precursor protein (APP) affects the activity and the level of PLD expression in P19 embryonic carcinoma cells. We observed that the unstimulated basal PLD activity was higher in wild-type APP(695)-transfected cells than in non-transfected control cells. The protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate (PMA), has been shown to activate PLD. PMA-stimulated PLD activity was 3-fold higher in the APP overexpressing cells than in the control cells. P19 cells express two distinct PLD isozymes, PLD1 and PLD2. The level of PLD2 expression was increased by APP overexpression. Although the PKC inhibitor, GF109203X, inhibited PMA-stimulated PLD activity, it did not affect the high basal PLD activity induced by APP overexpression. Neuronal differentiation of the P19 cells by retinoic acid did not affect the basal or PMA stimulated-PLD activity. Interestingly, APP overexpression in the differentiated P19 cells also led to an increase in PLD activity. The PLD activity of the P19 cells is apparently regulated by amyloid protein through both PKC-dependent and -independent mechanisms.

Apoptotic cell death induced by Acinetobacter baumannii in epithelial cells through caspase-3 activation

Epithelial cell death induced by Acinetobacter baumannii infection was investigated using in vitro assays. Eight hours after live A. baumannii infection, HeLa cells exhibited detachment from the dish, rounding morphologies, high proportions of trypan blue-positive cells and extensive DNA breakdown with faint apoptotic banding, which is indicative of cells undergoing apoptosis. The enzymatic activity of caspase-3 was increased in cells as early as 2 h after infection. In addition, apoptosis of HeLa cells was induced by treatment with bacterial culture filtrates but not with formalin-killed bacteria. These results indicate that A. baumannii infection triggers apoptosis in HeLa cells through caspase-3 activation.

Apolipoprotein E polymorphism and lipid levels differ by gender and family history of diabetes: the Rancho Bernardo Study

Association between apolipoprotein E (apoE) gene polymorphism and lipid levels was studied in 164 nondiabetic first-degree relatives of persons with diabetes and 962 nondiabetic persons with no family history of diabetes. Sex-specific genotypic distribution of apoE polymorphism did not differ between persons with and without a family history of diabetes. In first-degree relatives, lipid levels did not differ among persons with apoE2 (E2/2, E2/3), apoE3/3, and apoE4 (E4/4, E3/4) after adjusting for age, waist circumference, smoking, and alcohol and estrogen use. In persons without a family history of diabetes, both men (p<0.01) and women (p<0.001) with apoE2 showed lower levels of total and low density lipoprotein cholesterol compared with persons with apoE3/3 and apoE4. In women with a family history of diabetes, persons with apoE4 had larger waist circumference (p<0.05). ApoE2 allele is associated with more favorable levels of total and low density lipoprotein cholesterol in men and women without a family history of diabetes. ApoE4 allele is associated with obesity independent of dyslipidemia in women but not men with a family history of diabetes. ApoE polymorphism is not associated with lipids in men or women with a family history of diabetes.

The prevalence of trimethoprim-resistance-conferring dihydrofolate reductase genes in urinary isolates of Escherichia coli in Korea

One-hundred and twenty-two urinary isolates of Escherichia coli were studied for trimethoprim resistance. Seventy-seven (63.1%) of the 122 isolates were found to be resistant to trimethoprim. Of the 77 trimethoprim-resistant isolates, 75 dfr genes were detected in 72 isolates as follows: the dfrA17 gene was the most prevalent, being found in 27 isolates, followed by dfrA12 in 26, dfrA1 in 15, dfrA5 in four and dfrA7 in three. Southern blot and PCR mapping analysis revealed that all of the dfrA17, dfrA12, dfrA5 and dfrA7 genes were located on class 1 integrons. The dfrA1 gene inserted as a gene cassette in class 1 integrons was found in 10 of 15 isolates, and the intI2 gene of Tn7 was detected in two out of five isolates. In conjugation experiments, the dfr genes inserted in class 1 integrons were transferred to a recipient E. coli in 32 (42.7%) of the 75 dfr genes. In conclusion, the dfrA17 and dfrA12 genes were the most prevalent genes responsible for trimethoprim resistance in urinary tract isolates of E. coli from Korea and the dfr genes inserted in integrons are more widespread than those that are not related to gene cassettes.

Peripheral blood mitochondrial DNA content is related to insulin sensitivity in offspring of type 2 diabetic patients

OBJECTIVE

To investigate whether the peripheral blood mtDNA (pb-mtDNA) content is decreased and linked to insulin resistance in the offspring of type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

A total of 82 offspring of type 2 diabetic patients and 52 age-, sex-, and BMI-matched normal subjects from the Mokdong, Korea, population were selected for this study by stratified, randomized sampling. Of the offspring of diabetic patients, 52 had normal glucose tolerance (NGT), 21 had impaired glucose tolerance (IGT), and 9 had newly diagnosed type 2 diabetes. The pb-mtDNA content was measured by real-time polymerase chain reaction with a mitochondria-specific fluorescent probe, normalized by a nuclear DNA, 285 rRNA gene. The associations between pb-mtDNA content and several parameters of insulin resistance were studied.

RESULTS

The pb-mtDNA contents tended to be lower in the 82 offspring of type 2 diabetic patients (1,084.7 +/- 62.6 vs. 1,304.0 +/- 99.2 in the offspring and control subjects, respectively, P = 0.051) and was significantly lower in the combined NGT and IGT offspring group (NGT+IGT, 1,068.0 +/- 67.8, P < 0.05) than in the control subjects. In NGT+IGT offspring, the pb-mtDNA content was significantly correlated with logarithmically transformed insulin sensitivity (r = 0.253, P < 0.05) and was the main predictor of insulin sensitivity.

CONCLUSIONS

Quantitative mtDNA status might be a hereditary factor associated with type 2 diabetes and could serve as an indicator for insulin sensitivity.

Antimicrobial resistance of Shigella sonnei in Korea during the last two decades

Eighty-eight strains of Shigella sonnei isolated in Korea during the period 1980 to 1999 were tested for susceptibility to 13 antimicrobial agents. S. sonnei isolates demonstrated high frequencies of resistance to sulfamethoxazole (97.7%), tetracycline (96.6%), and trimethoprim (95.5%). S. sonnei isolates from the 1990s were more resistant to nalidixic acid than isolates from the 1980s (100 vs 7.7%), while isolates from the 1990s were more susceptible to chloramphenicol than isolates from the 1980s (0 vs 100%). Ampicillin-resistant S. sonnei isolates produced the TEM-1 beta-lactamase with a pI of 5.4. The TEM-1 gene was located on conjugally transferable plasmids in the majority of isolates. S. sonnei isolates were all susceptible to cefotaxime, cefoxitin, ceftazidime, ciprofloxacin, and norfloxacin. These results indicate that cephalosporins and quinolones may be alternative antibiotics for the treatment of S. sonnei infections in Korea.

The design and development of a biosensor to measure the concentration of meconium in amniotic fluid

Meconium aspiration syndrome occurs in 0.2% to 1% of all deliveries and has a mortality rate as high as 18%. The disease is responsible for 2% of all perinatal deaths. Meconium may be classified as being thick or thin, but this assessment is normally performed visually by clinicians. A "meconiumcrit" analysis has been developed to objectively define the concentration of meconium. However, this analysis does not provide real-time continuous readings. This study focused on the design and development of a sensor to provide an objective, continuous, real-time assessment of meconium thickness. Meconium has an absorption spectrum centered at 410 nm and observes Beer's law. Blue light centered at 430 nm was delivered through meconium solutions, and a photodiode translated the strength of the incoming light into a voltage. This voltage was analyzed by a microcontroller to determine the concentration of meconium.

The HslU ATPase acts as a molecular chaperone in prevention of aggregation of SulA, an inhibitor of cell division in Escherichia coli

HslVU is an ATP-dependent protease consisting of two multimeric components: the HslU ATPase and the HslV peptidase. SulA, which is an inhibitor of cell division and has high tendency of aggregation, is degraded by HslVU protease. Here we show that HslU plays a role not only as a regulatory component for the HslV-mediated proteolysis but also as a molecular chaperone. Purified HslU prevented aggregation of SulA in a concentration-dependent fashion. This chaperone activity required oligomerization of HslU subunits, which could be achieved by ATP-binding or in the presence of high HslU protein concentrations. hsl mutation reduced the SulA-mediated inhibition of cell growth and this effect could be reversed upon overproduction of HslU, suggesting that HslU promotes the ability of SulA to block cell growth through its chaperone function. Thus, HslU appears to have two antagonistic functions: one as a chaperone for promotion of the ability of SulA in cell growth inhibition by preventing SulA aggregation and the other as the regulatory component for elimination of SulA by supporting the HslV-mediated degradation.

The possibility of gene therapy for the treatment of choroidal neovascularization

PURPOSE

Choroidal neovascularization (CNV) is responsible for most cases of severe visual loss in age-related macular degeneration. Recently, the possibility of gene therapy has been proposed for the treatment of CNV. The purpose of this study was to examine the feasibility of ex vivo and in situ gene therapy approaches for CNV.

DESIGN

Experimental study.

METHODS

Human retinal pigment epithelial (RPE) cells were transduced with a retroviral vector coding for beta-galactosidase. Transduced cells were grown on type II collagen sheets and transplanted under the retina of 20 rabbits. Animals were observed for 3 to 56 days, and transplanted cells were examined histologically and with X-gal staining. Bovine choroidal endothelial cells (CEC) were transduced with retroviral vectors coding for tissue inhibitor of metalloproteinase-2 (TIMP-2) or control vector. Production of TIMP-2 by transduced cells was determined by immunohistochemical analysis and enzyme-linked immunosorbent assay. Effect of transduction on in vitro proliferation, migration, and tube formation was examined in response to vascular endothelial growth factor (VEGF). Four CNV lesions were induced in one cynomolgus monkey by laser photocoagulation. Two days later, retroviral vector coding for TIMP-2 or control vector was injected into the subretinal space overlying the CNV lesions. The monkey was observed for 12 weeks using fluorescein angiography.

RESULTS

Transplantation of transduced RPE cells was technically achieved in 10 of 20 animals. In these animals, RPE cells at the site of transplantation formed a monolayer and expressed beta-galactosidase for 14 days. beta-Galactosidase-positive cells were not identified at 56 days. Choroidal endothelial cells transduced with TIMP-2 secrete TIMP-2 into the media and show decreased migration and tube formation in vitro. In the in vivo monkey model, the control CNV lesions (n = 2) showed prominent leakage, whereas the experimental lesions (n = 2) showed minimal hyperfluorescence.

CONCLUSIONS

Retrovirally transduced RPE cells survive in the subretinal space for at least 14 days and continue to express the gene product coded for by the vector. Choroidal endothelial cells retrovirally transduced for TIMP-2 produce TIMP-2 in vitro and show decreased angiogenic responses in vitro in response to VEGF. A preliminary study attempting in situ delivery of TIMP-2 vector to CNV lesions in a monkey eye supports the feasibility of this approach and encourages further study.

MMA/MPEOMA copolymers as coating materials for improved blood compatibility: protein adsorption study

Surface-induced thrombosis remains one of the main problems in the development of blood-contacting devices. When a foreign surface comes in contact with blood, the initial blood response is adsorption of blood proteins, followed by platelet adhesion and activation, leading to thrombus formation. A particularly effective polymer for the prevention of protein adsorption and platelet adhesion appears to be polyethylene oxide (PEO). In this study, water-insoluble copolymers of methyl methacrylate (MMA) and methoxy PEO monomethacrylates (MPEOMA) with different PEO molecular weights (200, 400, and 1000) and monomer composition were synthesized and characterized by gel permeation chromatography and 1H-nuclear magnetic resonance spectroscopy. The synthesized copolymers were coated on glass slides by a spin coating method to prepare PEO-rich surfaces as blood-compatible surfaces. The surface properties of the copolymers and their interaction with blood proteins (albumin, gamma-globulin, fibrinogen, and plasma proteins) were investigated by the measurement of water contact angles and by electron spectroscopy for chemical analysis, respectively. It was observed that the protein adsorption on the copolymer surfaces decreased with increasing PEO molecular weight and MPEOMA content in the copolymers. The copolymers with long PEO chains in MPEOMA (MMA/MPEO1000MA copolymers) were effective in preventing protein adsorption, even though their MPEOMA content was less than the copolymers with shorter PEO chains.

ATP-dependent degradation of SulA, a cell division inhibitor, by the HslVU protease in Escherichia coli

HslVU is an ATP-dependent protease consisting of two multimeric components, the HslU ATPase and the HslV peptidase. To gain an insight into the role of HslVU in regulation of cell division, the reconstituted enzyme was incubated with SulA, an inhibitor of cell division in Escherichia coli, or its fusion protein with maltose binding protein (MBP). HslVU degraded both proteins upon incubation with ATP but not with its nonhydrolyzable analog, ATPgammaS, indicating that the degradation of SulA requires ATP hydrolysis. The pulse-chase experiment using an antibody raised against MBP-SulA revealed that the stability of SulA increased in hsl mutants and further increased in lon/hsl double mutants, indicating that SulA is an in vivo substrate of HslVU as well as of protease La (Lon). These results suggest that HslVU in addition to Lon plays an important role in regulation of cell division through degradation of SulA.

ATP hydrolysis activity of the DEAD box protein Rok1p is required for in vivo ROK1 function

The yeast ROK1 gene has been initially identified as a high copy plasmid suppressor of the kem1 null mutation and implicated in microtubule-mediated functions. Based on the deduced amino acid sequence of the ROK1 gene, Rok1p has been classified in the DEAD protein family of ATP-dependent RNA helicases. A subsequent report has suggested that Rok1p is required for rRNA processing. We report here the first study on the biochemical activity associated with Rok1p. The MBP-Rok1 hybrid protein was synthesized in Escherichia coli and purified by amylose affinity column and ion exchange chromatography. Rok1p has ATP hydrolysis activity. The significance of the conserved ATPase domains was addressed by generating a series of amino acid substitution mutations in these domains. Both in vivo lethality tests of the mutations and biochemical characterization of the mutant proteins suggest that ATP hydrolysis activity of Rok1p is essential for ROK1 function. The ATPase activity of Rok1p appears to be independent of single-stranded RNA. Furthermore, replacement of the first Arg in the HRIGR domain, the known RNA-binding domain, with Thr, Ile or Lys has no detectable effect on in vivo ROK1 function. The lack of RNA dependency and some of the mutational phenotypes of ROK1 differentiate this gene from other members of the family.

LonR9 carrying a single Glu614 to Lys mutation inhibits the ATP-dependent protease La (Lon) by forming mixed oligomeric complexes

An unusual lon mutation (called lonR9) is dominant over the wild-type gene, which encodes the ATP-dependent protease La (Lon) in Escherichia coli, when present in multicopy plasmids. Here, we cloned and sequenced lonR9, and showed that the mutant gene carries a single point mutation in its open reading frame, which leads to replacement of Glu614 by Lys. The LonR9 protein and its poly-His-tagged form were purified to apparent homogeneity. Both of the purified proteins were capable of inhibiting the ATP-dependent proteolysis and the protein-activated ATP hydrolysis by protease La. Furthermore, the His-tagged LonR9 protein was found to form mixed oligomeric complexes with protease La, upon analysis by chromatography on a metal-chelating column. These results suggest that the phenotypic dominance of the lonR9 mutant is due to the formation of mixed oligomeric complexes between LonR9 and protease La, in which the defective components prevent the function of the wild-type subunits.

NMR analyses of the interactions of human annexin I with ATP, Ca2+, and Mg2+

Human annexin I is a member of the annexin family of calcium-dependent phospholipid binding proteins. The structure of an N-terminally truncated human annexin I (delta-annexin I) and its interactions with Ca2+, Mg2+, and ATP were studied at the atomic level using nuclear magnetic resonance (NMR) spectroscopy. Since delta-annexin I is a large protein, with a molecular weight of 35 kDa, a site-specific (carbonyl-13C, amide-15N) labeling technique was used to determine the interaction sites of delta-annexin I with Ca2+, Mg2+, and ATP. The 13C NMR study focused on the carbonyl carbon resonances of the histidine residues of delta-annexin I. We found that ATP binds to delta-annexin I, and that the ATP binding site is located in the 1-domain of annexin I. We also found that histidine-52 is involved in that site, and that the binding ratio of ATP to delta-annexin I is 1:1.