Staphylococcus aureus Virulence Affected by an Alternative Nisin A Resistance Mechanism.

Nisin A is a bacteriocin produced by Lactococcus lactis and is widely used as a food preservative. Staphylococcus aureus has the BraRS-VraDE system that provides resistance against low concentrations of nisin A. BraRS is a two-component system that induces the expression of the ABC transporter VraDE. Previously, we isolated a highly nisin A-resistant strain with increased VraDE expression due to a mutation in braRS In this study, we isolated S. aureus MW2 mutants with BraRS-VraDE-independent nisin A resistance. These mutants, designated SAN2 ( S.aureusnisin resistant) and SAN469, had a mutation in pmtR, which encodes a transcriptional regulator responsible for the expression of the pmtABCD operon. As a result, these mutants exhibited increased expression of PmtABCD, a transporter responsible for the export of phenol-soluble modulin (PSM). Characterization of the mutants revealed that they have decreased susceptibility to human ß-defensin-3 (hBD3) and LL37, which are innate immune factors. Additionally, these mutants showed higher hemolytic activity than the original MW2 strain. Furthermore, in a mouse bacteremia model, the SAN2 strain exhibited a lower survival rate than the original MW2 strain. These results indicate that the increased expression of pmtABCD due to a pmtR mutation is an alternative nisin A resistance mechanism that also affects virulence in S. aureusIMPORTANCE Recently, the emergence of antibiotic-resistant bacteria has resulted in serious problems for chemotherapy. In addition, many antibacterial agents, such as disinfectants and food additives, are widely used. Therefore, there is a possibility that bacteria are becoming resistant to some antibacterial agents. In this study, we investigated whether Staphylococcus aureus can become resistant to nisin A, one of the bacteriocins applied as a food additive. We isolated a highly nisin A-resistant strain designated SAN2 that displayed increased expression of Pmt proteins, which are involved in the secretion of virulence factors called phenol-soluble modulins (PSMs). This strain also showed decreased susceptibility to human antimicrobial peptides and increased hemolytic activity. In addition, SAN2 showed increased lethal activity in a mouse bacteremia model. Our study provides new insights into the possibility that the acquisition of resistance against food preservatives may modulate virulence in S. aureus, suggesting that we need to pay more attention to the use of food preservatives together with antibiotics.

Acantholytic squamous cell carcinoma of the lung with marked lymphogenous metastases and high titers of myeloperoxidase-antineutrophil cytoplasmic antibodies: a case report.

BACKGROUND: Acantholytic squamous cell carcinoma (ASQCC), histologically characterized by intercellular bridge loosening, is recognized as a rare variant of squamous cell carcinoma (SQCC). ASQCC may demonstrate a worse prognosis than conventional SQCC. Pulmonary ASQCC is particularly rare; its biological behavior and prognostic data have not been reported. CASE PRESENTATION: We report the clinical and autopsy findings of a 71-year-old Japanese man with pulmonary ASQCC. Pulmonary lesions, suggestive of idiopathic interstitial pneumonia, were radiologically observed 3 and 6 years prior to the patient's most recent hospitalization; however, the patient did not undergo further medical examinations. Upon being discovered unconscious, the patient was admitted to our hospital. Dehydration and lower limb muscle weakness were noted, as were laboratory findings of coagulation abnormalities and renal dysfunction. Computed tomography helped confirm a 21-mm peripheral nodule in the upper left lobe of the lung, with associated swollen lymph nodes in the bilateral hilar, mediastinal, and para-aortic regions. Brain and spinal lesions, suggestive of neurological disturbances, were not found. Small cell lung carcinoma was suspected, upon admission, but high serum levels of squamous cell carcinoma antigen and cytokeratin-19 fragments were present. Therefore, advanced lung cancer, possibly SQCC, was diagnosed. The patient was treated with best supportive therapy, and died one month after admission. Hypercalcemia and high serum levels of parathyroid hormone-related protein (PTHrP) and myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) titers were observed. Progressive renal insufficiency was absent due to improved renal function subsequent to hydration. An autopsy helped confirm the left lung tumor as an ASQCC associated with pulmonary lymphangitic carcinomatosis and multiple metastases in the lungs and lymph nodes. Skin lesions suggesting malignant tumors were absent. The metastatic lesions consisted largely of acantholytic tumor cells, and the lungs showed usual interstitial pneumonia pattern; vasculitis was absent. CONCLUSIONS: This is the first reported case of pulmonary ASQCC resulting in an aggressive clinical course, with marked lymphogenous metastases and PTHrP-associated hypercalcemia. The high serum MPO-ANCA titers were clinicopathologically insignificant, but may have been related to the pulmonary interstitial lesion. Pulmonary ASQCC represents a highly malignant subset of lung cancer.

Incidence of hepatitis B virus reactivation in patients with resolved infection on immunosuppressive therapy for rheumatic disease: a multicentre, prospective, observational study in Japan.

BACKGROUND: Although the reactivation of hepatitis B virus (HBV) is recognised as a serious complication in patients with rheumatic disease (RD) receiving immunosuppressive drugs (ISDs), the incidence and risk factors for reactivation remain controversial. OBJECTIVES: To investigate the incidence and risk factors for HBV reactivation in patients with RD. METHODS: We performed a multicentre, observational, prospective study over 2 years in patients with resolved HBV infection. Patients with RD treated with a dose of ≥5 mg/day prednisolone and/or synthetic or biological ISDs with negative HB virus surface antigen and positive anti-HB virus surface antibody (HBsAb) and/or anti-HB virus core antibody (HBcAb) were enrolled. Quantitative HBV DNA results and related data were regularly recorded. RESULTS: Among 1042 patients, including 959 with rheumatoid arthritis, HBV DNA was detected in 35 (1.93/100 person-years), with >2.1 log copies/mL observed in 10 patients (0.55/100 person-years). None of the reactivated patients, including seven treated with a nucleic acid analogue, showed overt hepatitis. Low HBsAb titres and advanced age seemed to be risk factors for HBV reactivation; however, reactivation was observed in three patients with positive HBsAb and negative HBcAb test results. The risk of reactivation was lower with methotrexate but higher with prednisolone among the different types of ISDs. The intervals from the start of ISD to reactivation were relatively long (3-182 months; median, 66 months). CONCLUSIONS: The incidence of HBV reactivation with ISD use was 1.93/100 person-years in patients with RD with resolved HBV infection. No overt hepatitis was observed in the reactivated patients.

Two-Component Systems Involved in Susceptibility to Nisin A in Streptococcus pyogenes.

UNLABELLED: Two-component systems (TCSs) are regulatory systems in bacteria that play important roles in sensing and adapting to the environment. In this study, we systematically evaluated the roles of TCSs in the susceptibility of the group A Streptococcus (GAS; Streptococcus pyogenes) SF370 strain to several types of lantibiotics. Using individual TCS deletion mutants, we found that the deletion of srtRK (spy_1081-spy_1082) in SF370 increased the susceptibility to nisin A, which is produced by Lactococcus lactis ATCC 11454, but susceptibility to other types of lantibiotics (nukacin ISK-1, produced by Staphylococcus warneri, and staphylococcin C55, produced by Staphylococcus aureus) was not altered in the TCS mutants tested. The expression of srtFEG (spy_1085 to spy_1087), which is located downstream of srtRK and is homologous to ABC transporters, was increased in response to nisin A. However, srtEFG expression was not induced by nisin A in the srtRK mutant. The inactivation of srtFEG increased the susceptibility to nisin A. These results suggest that SrtRK controls SrtFEG expression to alter the susceptibility to nisin A. Further experiments showed that SrtRK is required for coexistence with L. lactis ATCC 11454, which produces nisin A. Our results elucidate the important roles of S. pyogenes TCSs in the interactions between different bacterial species, including bacteriocin-producing bacteria. IMPORTANCE: In this study, we focused on the association of TCSs with susceptibility to bacteriocins in S. pyogenes SF370, which has no ability to produce bacteriocins, and reported two major new findings. We demonstrated that the SrtRK TCS is related to susceptibility to nisin A by controlling the ABC transporter SrtFEG. We also showed that S. pyogenes SrtRK is important for survival when the bacteria are cocultured with nisin A-producing Lactococcus lactis This report highlights the roles of TCSs in the colocalization of bacteriocin-producing bacteria and non-bacteriocin-producing bacteria. Our findings provide new insights into the function of TCSs in S. pyogenes.

Slowly Expanding 18 F-FDG PET-Positive Irregular Opacities in the Lung Due to Diffuse Lymphoid Hyperplasia Preceding Rheumatoid Arthritis.

ABSTRACT: Pulmonary diffuse lymphoid hyperplasia (DLH), a nonneoplastic lymphoproliferative disorder (LPD), is extremely rare, and no PET/CT findings have been reported for pulmonary DLH. We observed slowly expanding irregular opacities with 18 F-FDG accumulation (SUV max , 3.64) in the right lower lobe of a 51-year-old asymptomatic man. The patient underwent video-assisted thoracoscopic biopsy on suspicion of malignant lesions. Histologically, no neoplastic cells were present, and the lesion was consistent with DLH. Six months later, the patient developed rheumatoid arthritis. DLH should be considered in the differentiation of PET-positive irregular opacities, even in the absence of known immune abnormalities.

Positron emission tomography/computed tomography: a clinical tool for evaluation of enthesitis in patients with spondyloarthritides.

OBJECTIVE: To evaluate the accuracy of PET/CT using [(18)F]fluorodeoxyglucose (FDG) in determining the presence of enthesitis in patients with SpAs. METHODS: Results of PET/CT scans of eight patients with SpA and seven patients with RA were retrospectively examined, with specific focus on five joints and three entheses. Volume fixation values are expressed as standardized uptake values (SUVs). Data from 20 patients with non-rheumatic (NR) diseases and 20 healthy subjects were also examined if non-specific, false positive findings were possible. We evaluated the clinical utility of PET/CT examinations in SpA, compared with MRI and Ga scintigraphy. RESULTS: Images of PET/CT scans of the shoulder, hip and knee joints revealed that FDG accumulated at the entheses in SpA and in the synovium in RA patients. The maximum SUVs [mean (s.d.)] were statistically higher in SpA patients compared with RA patients at the entheses of lumbar spinous process [4.83 (1.15) vs 1.42 (0.34); P < 0.05, respectively], pubic symphysis [3.93 (0.87) vs 1.35 (0.31); P < 0.05, respectively] and ischial tuberosity [4.76 (1.5) vs 1.35 (0.42); P < 0.05, respectively]. The positive frequencies of lumbar spinous processes and ischial tuberosity evaluated by PET/CT scan in the SpA group were significantly higher than that evaluated by MRI. CONCLUSION: MRI is now widely used to detect bone marrow oedema and enthesitis in patients with SpA. PET/CT scans offer an alternative method to identify enthesitis, and will likely contribute to the early diagnosis of SpA.

Dyskeratotic cells in persistent pruritic skin lesions as a prognostic factor in adult-onset Still disease.

Adult-onset Still disease (AOSD), a systemic inflammatory disorder, is characterized by high fever, evanescent rash, arthritis, and hyperferritinaemia. AOSD is also reported to be associated with other skin lesions, including persistent pruritic papules and plaques. This study aimed to assess the significance of dyskeratotic skin lesions in Japanese AOSD patients.We retrospectively assessed the histology of persistent pruritic skin lesions and evanescent rashes and the relationship between dyskeratotic cells, serum markers, and outcomes in 20 Japanese AOSD patients, comparing AOSD histology with that of dermatomyositis (DM), drug eruptions, and graft-versus-host disease (GVHD).As the results, Persistent pruritic lesions were characterized by scattered single keratinocytes with an apoptotic appearance confined to the upper layer of the epidermis and horny layer without inflammatory infiltrate. In contrast to AOSD, the histology of DM, drug eruption, and GVHD demonstrated dyskeratotic cells in all layers of the epidermis with inflammatory infiltrate. AOSD with evanescent rash showed no dyskeratotic cells. The dyskeratotic cells in pruritic AOSD lesions stained positive for ssDNA and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling, indicating apoptosis. Serum IL-18 was significantly higher in AOSD patients with dyskeratotic cells than those without, and generally required higher doses of glucocorticoids, immunosuppressants, and biologic agents. Two of ten AOSD patients with dyskeratotic cells died from hemophagocytic lymphohistiocytosis.In conclusion, Persistent pruritic AOSD skin lesions are characterized by dyskeratotic cells with apoptotic features, involving the upper layers of the epidermis. There may be a link to elevated IL-18. This dyskeratosis may be a negative prognostic indicator.

Edaravone inhibits collagen-induced arthritis possibly through suppression of nuclear factor-kappa B.

OBJECTIVE: Rheumatoid arthritis (RA) is a chronic autoimmune disease which is induced by proinflammatory cytokines or oxidative stress. The activation of nuclear factor-kappa B (NF-kappaB) that contributed to imbalance between apoptosis and proliferation of rheumatoid synovial cells (SC). Edaravone, clinically available free radical scavenger in Japan, is confirmed to be beneficial in the acute stage of stroke. We aimed to investigate the suppressive effect of edaravone on collagen-induced arthritis (CIA) mice and on the activated molecules in SC stimulated by interleukin-1beta (IL-1beta). METHODS: Edaravone was administrated intravenously at a dose of 3mg/kg of body weight to CIA mice. The progression of CIA was evaluated by the macroscopic arthritis scoring system of paws. Interleukin-6 (IL-6) and matrix metalloproteinase-3 (MMP-3) concentrations in culture medium of human SC were measured by enzyme linked immunosorbent assays. Caspase-3/7 activity and nuclear factor-kappa B (NF-kappaB) protein level of cultured human SC were estimated by fluorometric assay and Western blot analysis, respectively. RESULTS: Edaravone significantly decreased macroscopic arthritis score in CIA mice. Acceleration of IL-6 and MMP-3 productions and attenuation of caspase-3/7 activity in IL-1beta-stimulated SC were abated by edaravone. Activated NF-kappaB in IL-1beta-stimulated SC was suppressed by edaravone. CONCLUSION: Edaravone, antioxidants available for clinical use, appears to have therapeutic effect on RA. We suggest that the inhibitory effect of edaravone on RA might be exerted, at least in part, through suppression of activated NF-kappaB. Therefore, we expect therapeutical use of edaravone as an anti-rheumatic agent.

Single mutations in BraRS confer high resistance against nisin A in Staphylococcus aureus.

Nisin A is a lantibiotic produced by Lactococcus lactis that is widely used as a food preservative. In Staphylococcus aureus, the BraRS two-component system (TCS) senses nisin A and regulates the expression of the ABC transporter VraDE, which is responsible for nisin A resistance. In this study, we exposed S. aureus to a sub-minimum inhibition concentration of nisin A and obtained three spontaneous mutants that were highly resistant to this lantibiotic, designated as SAN (S. aureus nisin resistant) 1, SAN8, and SAN87. In the wild-type S. aureus strain, VraDE expression was induced by nisin A. In contrast, SAN8 and SAN87 showed constitutively high VraDE expression, even in the absence of nisin A, while SAN1 showed higher BraRS expression, which resulted in high VraDE expression in the presence of nisin A. We identified a single mutation in the promoter region of braXRS in SAN1, whereas SAN8 and SAN87 had single mutations in braR and braS, respectively. Interestingly, even the unphosphorylated form of the mutant BraR protein induced VraDE expression. These results indicate that conformational changes in BraS or BraR resulting from the point mutations may result in the constitutive expression of VraDE, allowing S. aureus to adapt to high concentrations of nisin A.

Risk stratification and clinical course of hepatitis B virus reactivation in rheumatoid arthritis patients with resolved infection: final report of a multicenter prospective observational study at Japanese Red Cross Hospital.

BACKGROUND: The prophylaxis for hepatitis B virus (HBV) reactivation assumes that hepatic injury after reactivation is often rapidly progressive and can evoke fulminant hepatitis. The incidence and prognosis of reactivation in patients with rheumatoid arthritis (RA) may be different from those receiving organ transplantation and cancer chemotherapy. This study aimed to investigate the incidence, risk factors, and clinical course of HBV reactivation and develop a scoring system for risk stratification in RA patients with resolved infection. METHODS: HBV DNA was measured using real-time polymerase chain reaction, and patient data were collected for 4 years in RA patients with resolved HBV infection who were treated with steroids or synthetic or biologic immunosuppressive drugs. RESULTS: Among 1127 patients, HBV DNA was detected in 57 patients (1.65/100 person-years); none of the reactivated patients exhibited worsening of hepatic function. Multivariate logistical analysis revealed that age > 70 years and HB core antibody (HBcAb) positivity alone were independent risk factors for HBV reactivation. HBV DNA ≥ 2.1 log copies/mL was observed in 15 patients (0.43/100 person-years); seven patients were treated with nucleic acid analogs (NAAs), whereas the remaining eight were observed without treatment. Among reactivated cases, 15 cases changed to HBV DNA-negative status spontaneously, whereas 24 cases remained HBV DNA positive < 2.1 log copies/mL during the observation period. We designed the following scoring system: HBV reactivation risk score = 1 × (age > 70 years) + 2 × (HBcAb positivity alone) + 1 × (treatment other than methotrexate monotherapy). This revealed that patients with the highest score had an odds ratio of 13.01 for HBV reactivation, compared to those with the lowest score. CONCLUSIONS: Rapid progression and poor outcomes after HBV reactivation were not frequent in RA patients with resolved infection. Our new risk scoring system might be useful for screening and optimization of prophylactic treatment by distinguishing patients with significantly lower reactivation risk.

Glucose enhances protein tyrosine phosphatase 1B gene transcription in hepatocytes.

Protein tyrosine phosphatase 1B (PTP1B) is a negative regulator of the insulin receptor signal transduction pathway. We investigated the effects of glucose on PTP1B transcription in the human hepatocyte cell line Huh7. Using a reporter gene assay, we found that D-glucose dose-dependently enhanced the PTP1B promoter activity. Real-time PCR demonstrated that D-glucose also increased PTP1B mRNA expression. Protein kinase C (PKC) inhibitors partially but significantly inhibited the transactivation by D-glucose. Mithramycin, a Sp1 inhibitor, completely abrogated this transactivation. The deletion of three possible Sp1 sites in the promoter region of PTP1B significantly reduced the basal promoter activity and transactivation by D-glucose. Sp1 activation by PKC is one of the key mechanisms in the regulation of several gene expressions. Our data suggested that glucose enhanced PTP1B transcription through Sp1 activation by PKC. Increased hepatic PTP1B expression may partly explain glucose toxicity in diabetes.

A case of neurosyphilis accompanied by deterioration of type 2 diabetes management.

A 66-year-old man was admitted with visual impairment, functional disability, and worsening glycemic control. On admission, he had optic atrophy without diabetic retinopathy in both eyes, sensory impairment of the lower extremities, ataxia, and cognitive impairment. As both serum and cerebrospinal fluid tested positive for syphilis, he was diagnosed with neurosyphilis and treated with antibiotics. Functional ability and cognitive function improved after conducting syphilis treatment; we consequently started him on an insulin self-administration program. Two years later, his glycemic control has normalized. Dementia caused by neurosyphilis is one of the most important differential diagnoses of treatable dementia; hence, early diagnosis and early treatment are important.

Edaravone inhibits rheumatoid synovial cell proliferation and migration.

Rheumatoid arthritis (RA) is characterized by synovial proliferation and migration which is induced by proinflammatory cytokines or oxidative stress, followed by joint destruction. Edaravone, clinically available free radical scavenger in Japan, is confirmed to be beneficial in the acute stage of cerebral infarction. We aimed to investigate whether edaravone suppressed in vitro proliferation and migration of synovial cells (SC) induced by IL-1beta. SC proliferation and migration induced by IL-1beta were dose-dependently suppressed by edaravone at the clinically available concentration. These data suggest that edaravone has potential effects to suppress SC proliferation and migration, followed by suppression of synovial proliferation in RA. Therefore, edaravone, an antioxidant agent, might be a novel therapeutic agent which develops the new strategy for treatment of RA, and more detailed studies are required to establish the therapeutic effect of edaravone on RA in vivo.

A subserosal, pedunculated, multilocular uterine leiomyoma with ovarian tumor-like morphology and histological architecture of adenomatoid tumors: a case report and review of the literature.

BACKGROUND: Uterine leiomyomas are common uterine tumors, and typical cases of leiomyoma are easily diagnosed by imaging study. However, uterine leiomyomas are often altered by degenerative changes, which can cause difficulty and confusion in their clinical diagnosis. We describe the 17th reported case of a uterine leiomyoma clinically diagnosed as an ovarian tumor; however, the present case shows the most detailed radiological evaluation, including contrast-enhanced magnetic resonance imaging. We first show that a uterine leiomyoma can histologically mimic an adenomatoid tumor. CASE PRESENTATION: A 47-year-old premenopausal, nulliparous Japanese woman with a history of type 2 diabetes mellitus, hypertension, and hyperlipidemia had lower abdominal pain. Ultrasonography confirmed a 6-cm mass in the right-sided space of the pelvic cavity. Magnetic resonance imaging evaluation showed that a multilocular mass was present near the uterus, and a mucinous ovarian tumor was considered. Emergency surgery due to acute abdomen was performed under the diagnosis of pedicle torsion of the ovarian tumor. During surgery, a pedunculated uterine mass without stalk torsion was seen. The mass grossly contained serous and hemorrhagic fluids in the cavities, and pathology examination confirmed that the mass was a leiomyoma with hydropic and cystic degeneration. Anastomosing thin cord-like arrangements of the leiomyoma cells mimicked the architecture of adenomatoid tumors. The tumor cells were positive for the microphthalmia transcription factor but negative for other melanoma markers. Three days postoperatively, she was discharged without sequelae. CONCLUSIONS: Marked intratumoral deposition of fluids may induce the multilocular morphology of a tumor, and the cellular arrangement of the tumor cells with hydropic degeneration mimicked an adenomatoid tumor in this case. Clinicians need to be aware that a subserosal leiomyoma with cystic and hydropic degeneration can mimic an ovarian tumor, and pathologists should be aware that such leiomyomas can mimic adenomatoid tumors. Additionally, perivascular epithelioid cell tumors should not be diagnosed only based on its immunoreactivity for the microphthalmia transcription factor.

Effect of pitavastatin on transactivation of human serum paraoxonase 1 gene.

Hepatic hydroxymethyl glutary coenzyme A HMG-CoA reductase inhibitors (statins) have various anti atherosclerosis pleiotropic effects that are independent of cholesterol reduction. Human serum paraoxonase 1 (PON1) is associated with high-density lipoprotein (HDL) and inhibits the oxidative modification of low-density lipoprotein (LDL). We investigated the effects of statins on PON1 gene transcription using a reporter gene assay. Promoter activity of the PON1 gene was estimated by measuring luciferase activity of plasmids with a PON1 promoter region transfected into human hepatoma HepG2 cells and human embryonic kidney (HEK) 293 cells. Pitavastatin, simvastatin, and atorvastatin each significantly increased PON1 promoter activity, and the transactivation by pitavastatin was abrogated by mevalonic acid and farnesyl pyrophosphate (FPP), however, not by geranylgeranyl pyrophosphate. Further, PON1 promoter activity was enhanced by farnesyl transferase inhibitor (FTI), but not by geranylgeranyl transferase inhibitor (GGTI). PON1 gene transcription has been reported to be dependent on Sp1 and the transactivation by pitavastatin was completely abrogated by mithramycin, an inhibitor of Sp1. Our results suggest that pitavastatin activates transcription of the PON1 gene through the FPP pathway, which may play an important role in the anti atherosclerotic effects of statins.

Pioglitazone prevents reactive hypoglycemia in impaired glucose tolerance.

A 42-year-old woman with hypoglycemic symptoms that occurred several hours after a meal visited our hospital. The hypoglycemic symptoms appeared when she was 37 years old, and her plasma glucose level had been assessed as less than 60 mg/dL when she experienced the symptoms. One year before, she had been diagnosed with reactive hypoglycemia by 75 g-oral glucose tolerance test (OGTT), which showed a normal glucose tolerance (NGT) pattern, and had begun taking an alpha-glucosidase inhibitor and nutritional treatment. A 75 g-OGTT on admission showed hypoglycemia at 240 min after glucose loading, excessive insulin secretion and an impaired glucose tolerance (IGT) pattern. A euglycemic-hyperinsulinemic clamp study demonstrated decreased insulin sensitivity. Therefore, we suspected that she had reactive hypoglycemia associated with insulin resistance and treated her with 15 mg/day pioglitazone. Her hypoglycemic symptoms completely disappeared after treatment with pioglitazone; insulin sensitivity in a euglycemic-hyperinsulinemic clamp study improved. Another 75 g-OGTT revealed that the excessive insulin secretion and hypoglycemia at 240 min after glucose loading had disappeared, and glucose tolerance was normalized from an IGT pattern to an NGT pattern. Thus, we believe that pioglitazone is effective for reactive hypoglycemia and aggravated glycemic metabolism associated with insulin resistance.

Type 1 diabetes developed in a type 2 diabetic patient with severe insulin resistance.

We report a 38-year-old female with severe insulin resistance who developed type 1 diabetes after being diagnosed with type 2 diabetes. At the initial examination, BMI was 31.8 kg/m(2) and HbA1c 10.8%. Her insulin secretion was sufficient (urinary CPR 80 microg/day) and the GAD antibody was negative. Following treatment with insulin and glimepiride, HbA1c decreased to 6.3%, though diabetic control deteriorated after 1 year (HbA1c, 11.0%) and her body weight was reduced in a short period, from 78 to 67 kg. Re-examination revealed that the GAD antibody was high (1870 U/mL, normal <1.5) and the anti-islet cell antibody positive, and insulin secretion decreased (urinary CPR 18 microg/day). Further, a hyperinsulinemic-euglycemic cramp study using an artificial pancreas showed that the patient had severe insulin resistance [glucose infusion rate 1.8 mg/(min kg); normal, 7.4+/-2.4 (mean+/-S.D.)]. An HLA-analysis showed that she was a homozygote of haplotype DRB1*0901-DQB1*0303. In spite of strict insulin therapy, glucose control was not improved. Pioglitazone could not be used because of side effects, however, metformin was effective for glucose control. The accumulation of case reports of patients with type 1 diabetes and insulin resistance is important for studying the relationship between the onset of the disease and insulin resistance, and for developing an effective treatment strategy.

Roles of Sp1 and protein kinase C in regulation of human serum paraoxonase 1 (PON1) gene transcription in HepG2 cells.

Human serum paraoxonase 1 (PON1) is associated with high-density lipoprotein, and inhibits oxidative modification of low-density lipoprotein in vitro. Therefore, PON1 is supposed to protect against atherosclerosis in vivo. In this study, we investigated the direct effect of Sp1 on PON1 transcription in HepG2 cells using a reporter gene assay. A deletion analysis of the PON1 upstream region revealed that dominant promoter elements were present within a sequence between -269 and -97bp, which contained a consensus binding site for Sp1, and an electrophoretic mobility shift analysis (EMSA) indicated the Sp1 binding to the upstream sequence. In accordance with this, overexpression of Sp1 dramatically enhanced PON1 promoter activity, and the Sp1 inhibitor mithramycin inhibited Sp1-induced promoter activation in a dose-dependent manner. The basal promoter activity was also enhanced by phorbol 12-myristate 13-acetate (PMA), and synergistic promoter activation was observed when Sp1-transfected cells were treated with PMA. The PMA-induced promoter activation was inhibited by mithramycin. In addition, overexpression of the dominant negative version of PKCalpha or zeta, significantly reduced PON1 promoter activity. These data suggest that Sp1 acts as a positive regulator of PON1 transcription, and that an interaction between Sp1 and PKC is a key mechanism for the effect of Sp1 on PON1 transcription.

Regulation of human glucocorticoid receptor gene transcription by Sp1 and p53.

The human glucocorticoid receptor (hGR) gene has several GC boxes in the promoter 1C region. We studied the effects of Sp1 and p53 on promoter 1C in HepG2 and HEK293 cells using luciferase (Lu) reporter assay. The results showed that the first GC box upstream of the transcription site activated the hGR promoter and over-expression of Sp1 obviously enhanced the activity. A mutant Lu-hGR vector, whose first GC box was defective, lost promoter activity nearly completely. Further, over-expression of p53 strongly suppressed the stimulating effect of Sp1 on hGR promoter activity. We concluded that Sp1 activates the hGR gene promoter, at least in part, by acting on the first GC box in promoter 1C, while p53 suppresses the transactivation by Sp1. These phenomena, demonstrated in cultured cells, may be important for the expression of hGR in vivo.