Time-varying closed-loop modeling of autonomic control in pediatric obstructive sleep apnea syndrome during cold face stimulation

Adults with obstructive sleep apnea syndrome (OSAS) are known to have impaired autonomic function but the corresponding effects in children appear to be more subtle. Model-based analysis of the cardiovascular response to cold face test (CFT) was used to quantify daytime autonomic dysfunction. The increase in transfer gain between respiration and RRI was not different between controls and OSAS. However, the transfer gain between "surrogate cardiac output" (pulse pressure+R-R interval) and systolic blood pressure (SBP) and the transfer gain between cardiac output and SBP both increased significantly in controls but not in OSAS during CFT. These findings suggest that the parasympathetic function remains relatively normal in pediatric OSAS, but cardiovascular sympathetic reactivity is impaired.

Delayed and competitively inhibited excretion of urinary hippuric acid in field workers coexposed to toluene, ethyl benzene, and xylene

The purpose of this study was to investigate whether the metabolic suppression of hippuric acid (HA) occurs in field workers coexposed to toluene, xylene and ethyl benzene. Eleven male spray painters were recruited into this study and monitored for 2 weeks using a repeated-measures study design. The sampling was conducted for 3 consecutive working days each week. Toluene, ethyl benzene, and xylene in the air were collected using 3M 3500 organic vapor monitors. Urine samples were collected before and after work shift, and urinary HA, methyl hippuric acid, mandelic acid, and phenylgloxylic acid concentrations were determined. In the first week, toluene concentrations were 2.66 +/- 0.95 (mean +/- SE) ppm, whereas ethyl benzene and xylene concentrations were 27.84 +/- 3.61 and 72.63 +/- 13.37 ppm, respectively, for all subjects. Pre-work shift HA concentrations were 230.23 +/- 37.31 mg/g creatinine, whereas pre-work shift HA concentrations were 137.81 +/- 14.15 mg/g creatinine. Mean urinary HA concentration was significantly greater in the pre-work shift samples than in the pre-work shift samples (p = 0.043). In the second week, toluene concentrations were much lower (0.28 ppm), whereas ethyl benzene and xylene were 47.12 +/- 8.98 and 23.88 +/- 4.09 ppm, respectively, for all subjects. Pre-work shift HA concentrations were 351.98 +/- 116.23 mg/g creatinine, whereas pre-work shift HA concentrations were 951.82 +/- 116.23 mg/g creatinine. Mean urinary HA concentration was significantly greater in the pre-work shift samples than in the pre-work shift samples (p <0.01); a significant correlation (r = 0.565; p = 0.002) was found between pre-work shift urinary HA levels and ethyl benzene exposure. This study showed that urinary HA peak was delayed to next morning for workers coexposed to toluene, ethyl benzene, and xylene; xylene and ethyl benzene probably played competitive inhibitors for metabolism of toluene. The study also presumed that urinary HA became the major metabolite of ethyl benzene at the end of work shift, when the exposure concentrations of ethyl benzene were 2.0 times those of xylene.

Remission of nephrotic membranous glomerulonephritis after high-dose trimethoprim-sulfamethoxazole treatment for pneumocystis jiroveci pneumonia

We report an unusual case of nephrotic syndrome due to membranous glomerulonephritis that responded to high-dose trimethoprim-sulfamethoxazole (TMP-SMX) treatment. A 52-year-old man presented with nephrotic syndrome and was diagnosed to have idiopathic membranous glomerulonephritis. At the time of diagnosis, his serum creatinine level was 1.2 mg/dl and daily urine protein excretion was 7.45 g. The patient was initially treated with angiotensin-converting enzyme inhibitor and diuretics. After a 6-month period, the patient remained symptomatic. Therefore, immunosuppressive therapy with a 6-month course of alternating corticosteroids with cyclophosphamide was commenced. Unfortunately, as a sequel of the immunocompromised state, the patient acquired severe pneumonia due to Pneumocystis jiroveci infection when he was on the fourth month of immunosuppressive therapy. At this time, he still had nephrotic range proteinuria and hypoalbuminemia. Because of the risk of aggravating infection, immunosuppressive agents were discontinued. A 14-day course of intravenous high-dose TMP-SMX therapy was given for the treatment of Pneumocystis jiroveci pneumonia. With this medication, not only the pneumonia was cured, but also a sustained remission of the nephrotic syndrome occurred. This case suggests a possible therapeutic role of high-dose TMP-SMX in membranous glomerulonephritis. We will discuss the possible mechanism.

Noninvasive assessment of cardiovascular autonomic control in congenital central hypoventilation syndrome

The goal of this study was to quantify autonomic system dysfunction, as manifested by cardiovascular and respiratory response abnormalities, in patients with congenital central hypoventilation syndrome (CCHS). During wakefulness, we continuously measured the ECG, arterial blood pressure (ABP), airflow, end-tidal CO2 partial pressure (PETCO2), and arterial oxygen saturation (SatO2) in each subject. These measurements were made during spontaneous breathing in supine, sitting and standing postures, and also when each subject tracked his/her prior spontaneous breathing pattern while supine. We also performed the cold face test, hyperoxic hypercapnic rebreathing and the isocapnic hypoxic rebreathing challenges. Using spectral analysis and modeling techniques, we sought to computationally delineate the physiological mechanisms that mediate these abnormalities, as well as to determine the extent to which these abnormalities are related to peripheral or central chemoreflex dysfunction. Our preliminary results support the notion that sympathetic tone is markedly elevated in CCHS, and that differences in autonomic control from normal controls can be delineated by observing the responses to different stressors.

Field protection effectiveness of chemical protective suits and gloves evaluated by biomonitoring

OBJECTIVES

To determine the effectiveness of protective suits and gloves by biomonitoring.

METHODS

Fifteen male spray painters at a ship coating factory were studied for two weeks. Workers wore no protective clothing during the first week and wore protective suits and gloves during the second week. Sampling was conducted on four consecutive working days each week. Ethyl benzene and xylene in the air were collected by using 3M 3500 organic vapour monitors. Urine was collected before and after each work shift.

RESULTS

Urinary mandelic acid (MA) and methyl hippuric acid (MHA) levels were divided by the personal exposure concentrations of ethyl benzene and xylene, respectively. Mean (SE) corrected MA and MHA concentrations in the first week were 1.07 (0.18) and 2.66 (0.68) (mg/g creatinine)/(mg/m3), and concentrations in the second week were 0.50 (0.12) and 1.76 (0.35) (mg/g creatinine)/(mg/m3) in the second week, respectively. Both MA and MHA concentrations in the second week (when spray painters wore protective suits and gloves) were lower than in the first week, respectively (p<0.001, p = 0.011). Mean decrease in MA and MHA biomarkers were 69% and 49%, respectively.

CONCLUSION

This study successfully evaluated the effectiveness of chemical protective suits and gloves by using biomarkers as urinary MA and MHA. This method is feasible for determining the performance of workers wearing personal protective equipment. Moreover, the experimental results suggest that dermal exposure may be the major contributor to total body burden of solvents in spray painters without protective suits and gloves.

Focal segmental glomerulosclerosis in association with Cushing's disease

Focal segmental glomerulosclerosis (FSGS) may be idiopathic or secondary to a variety of causes. Clinical distinction between primary and secondary forms of FSGS has crucial therapeutic consequences. Whereas the former may respond to immunosuppressive therapy, treatment of secondary forms of FSGS must aim to resolve the underlying diseases. Although the combination of nephrotic syndrome and Cushing's syndrome has been described anecdotally, the causal relationship between these two diseases remains controversial. We report herein a 37-year-old man who presented with lower extremity pitting edema. Heavy proteinuria and mild renal insufficiency prompted to perform a kidney biopsy and the specimen showed FSGS. On the other hand, admission physical examination was notable for a Cushingoid appearance. After endocrinological investigations, the patient was diagnosed as having Cushing's disease caused by pituitary adrenocorticotropic hormone-producing microadenoma. Immunosuppressive therapy for the treatment of FSGS was not carried out and we treated his Cushing's disease with transsphenoidal resection of the pituitary microadenoma. Surprisingly, resolution of heavy proteinuria occurred when the patient's physical features characteristic of Cushing's disease were gradually resolved 3 months later. This case suggests a possible association of Cushing's disease with FSGS.

Minimal change nephrotic syndrome in association with strongyloidiasis

Although parasitic infections have been known to be associated with immune complex-mediated glomerular lesions, strongyloidiasis-related glomerulopathy has not been well documented. We report a patient with delayed-recognized disseminated strongyloidiasis who developed nephrotic syndrome 3 months after the beginning of the manifestations related to strongyloidiasis. A kidney biopsy showed minimal change disease. We treated strongyloidiasis and hesitated to give steroid therapy for the treatment of minimal change nephrotic syndrome (MCNS) because of the risk of aggravation of Strongyloides stercoralis infection. Surprisingly, resolution of heavy proteinuria occurred after anthelmintic therapy with ivermectin. This case suggests a possible causal relationship between S. stercoralis infection and MCNS. In addition, a review of another 4 cases previously reported in the literature demonstrates the importance of detecting underlying S. stercoralis infection in patients with nephrotic syndrome since steroid therapy can cause hyperinfection or disseminated strongyloidiasis, and which may lead to fatal outcome.

Observation of two new N* peaks in J/psi-->ppi-n and ppi+n decays

The decay J/psi-->NNpi provides an effective isospin 1/2 filter for the piN system due to isospin conservation. Using 58x10(6) J/psi decays collected with the Beijing Electromagnetic Spectrometer at the Beijing Electron Positron Collider, more than 100 thousand J/psi-->ppi-n+c.c. events are obtained. Besides the two well-known N* peaks at around 1500 MeV/c2 and 1670 MeV/c2, there are two new, clear N* peaks in the ppi invariant mass spectrum around 1360 MeV/c2 and 2030 MeV/c2 with statistical significance of 11sigma and 13sigma, respectively. We identify these as the first direct observation of the N*(1440) peak and a long-sought missing N* peak above 2 GeV/c2 in the piN invariant mass spectrum.

Rescue treatment for cyclosporine-associated hemolytic-uremic syndrome with intravenous immunoglobulin

Hemolytic-uremic syndrome (HUS) is a rare complication occurring in solid-organ and bone marrow transplant recipients treated with calcineurin inhibitors cyclosporine or tacrolimus. We report here about a 30-year-old female cadaveric renal transplant recipient receiving cyclosporine who developed HUS in the early post-transplant period. Renal allograft biopsy specimens showed the characteristic features of thrombotic microangiopathy and acute cyclosporine nephrotoxicity. Cyclosporine was discontinued and the patient was switched to tacrolimus in conjunction with plasma exchange. Unfortunately, plasma exchange was interrupted by bleeding complication resulting from placement of double-lumen catheter. Intravenous immunoglobulin (IVIG) was then administrated as an alternative therapy. Hematological resolution occurred promptly and renal function recovered uneventfully. Our presenting case suggests the beneficial effect of IVIG on cyclosporine-associated HUS.

Microscopic polyangiitis atypically presenting with tubulointerstitial nephritis

A 65-year-old woman was admitted with a 4-week history of non-specific constitutional symptoms. Microscopic hematuria, proteinuria and mild renal insufficiency together with the presence of serum antineutrophil cytoplasmic antibodies prompted to perform a renal biopsy. The specimen showed tubulointerstitial nephritis without glomerular change. However, she developed purpura on lower limbs and hemoptysis, along with diffuse pulmonary infiltrates on chest radiograph, 2 weeks after admission. Skin and lung biopsies demonstrated leukocytoclastic vasculitis and diffuse alveolar hemorrhage, respectively. Microscopic polyangiitis was diagnosed based on clinical and pathological criteria. Clinical improvement occurred after intensive immunosuppressive therapy was given. This case illustrates an unusual renal presentation of tubulointerstitial nephritis in microscopic polyangiitis. The possible pathogenetic mechanism will be discussed.

Crescentic glomerulonephritis associated with rifampicin in a patient co-infected with tuberculosis and human immunodeficiency virus

A 73-year-old man presented with acute renal failure after 3-month standard antituberculosis therapy with rifampicin for pulmonary tuberculosis. Previously undiagnosed human immunodeficiency virus (HIV) infection was found at the same time. A kidney biopsy showed crescentic glomerulonephritis and tubulointerstitial nephritis. Furthermore, endothelial tubuloreticular inclusions were seen on electron microscopy. Rifampicin was stopped because it was considered as the most possible cause responsible for the rapidly progressive glomerulonephritis (RPGN). Immunosuppressive therapy was not carried out because of the risk of aggravation of underlying infectious diseases including tuberculosis and HIV. Fortunately, renal function recovered 1 month after discontinuation of rifampicin. This case presented a clinical challenge in the differential diagnosis of the cause for RPGN in such a complex condition and the therapeutic dilemma regarding the use of immunosuppressive drugs.

Remission of hepatitis B virus-associated membranoproliferative glomerulonephritis in a cirrhotic patient after lamivudine therapy

We describe a 39-year-old man with hepatitis B virus-(HBV) related chronic hepatitis who presented with nephrotic syndrome and decompensated cirrhosis. A kidney biopsy revealed membranoproliferative glomerulonephritis (MPGN) which was thought to be related to the HBV infection. Because interferon-alpha therapy was generally not recommended in patients with advanced liver disease, we chose lamivudine as an alternate treatment for the HBV-associated glomerulonephritis (GN). After 3-month treatment with oral lamivudine, resolution of the renal disease dramatically occurred together with improvement in liver function. To our knowledge, this is the first case of HBV-associated MPGN successfully treated with oral lamivudine therapy. The possible role of lamivudine in the treatment of HBV-associated GN is discussed.

Spinocerebellar ataxia type 6

We report a 39-year-old woman with spinocerebellar ataxia type 6. She presented with ataxia and a 3-year history of progressive ataxia and recurrent falls. There was no relevant family history. Genetic tests revealed an expanded allele of 24 CAG repeats at the spinocerebellar ataxia type 6 locus. This appears to be the first case reported in Hong Kong. As genetic testing becomes more widely available and clinical awareness increases, more such patients are expected to be diagnosed.

High-dose glucose-insulin-potassium treatment reduces myocardial apoptosis in patients with acute myocardial infarction

BACKGROUND

Several clinical trials have suggested that a metabolic cocktail of glucose-insulin-potassium (GIK) decreases mortality rates in patients with acute myocardial infarction (AMI). It has also been reported that Fas-mediated apoptosis plays an important role in ischaemic/reperfusion injury in the rat model. This study was designed to evaluate the interaction of ischaemic/reperfusion and reperfusion therapy coadministered with high-dose GIK treatment on soluble Fas/APO-1 (sFas) and Fas ligand (sFasL) plasma concentration in patients with AMI.

MATERIALS AND METHODS

Seventy-four patients presenting with AMI who underwent reperfusion therapy were randomized into a GIK group (n = 35) receiving high-dose GIK for 24 h or a vehicle group (n = 39). Thirty-four control subjects were also enrolled in the present study. Strepavidin-biotin ELISA was used to determine the soluble sFas and sFasL plasma concentration at baseline, 24 h (h), 3 day (d), 7 d and 14 d.

RESULTS

Soluble Fas and sFas-L serum concentrations ([sFas] and [sFas-L]) of patients with AMI were significantly elevated at baseline as compared with normal controls (NCs; P < 0.01 vs. NC). The sFas in the GIK and vehicle groups markedly decreased 24 h after the GIK infusion (10.7-->5.9 ng mL(-1) and 9.7-->6.5 ng mL(-1); P < 0.01 vs. baseline) and then increased during the 3-7-d period (5.9-->12.1 ng mL(-1) and 6.5-->11.1 ng mL(-1); P < 0.01 vs. 24 h). The GIK group demonstrated reduced sFas (12.1-->5.9 ng mL(-1)) at 14 d (P < 0.01 vs. 7 d), with no concomitant changes in the vehicle group. The sFas-L in the GIK and vehicle groups was not significant different during the 14-d period.

CONCLUSIONS

These results indicate that the sFas and sFasL in patients with AMI increased significantly compared with NC. Owing to the cardioprotective effects reported here and by others, a high-dose GIK infusion co-administered with the timely re-establishment of nutritive perfusion should be strongly considered as a treatment of choice for AMI. Additionally, sFas may be a valuable marker of the physiological response to ischaemic/reperfusion injury and reperfusion associated with high-dose GIK treatment.

Interleukin-1 receptor antagonist gene polymorphism in Taiwanese patients with gout

OBJECTIVE

The purpose of this study was to examine whether interleukin-1 receptor antagonist (IL-1Ra) gene polymorphism is a marker of susceptibility to or of the clinical characteristics of gout in Taiwanese patients.

METHODS

196 Taiwanese patients with gout and 103 unrelated normal healthy control subjects living in central Taiwan were studied. Polymorphism of the gene for IL-1Ra was typed from genomic DNA. Allelic frequencies and carriage rates were compared between gout patients and control subjects. The relationship between IL-1Ra genotypes and the clinical characteristics of gout was also evaluated.

RESULTS

No significant differences were observed in genetic and allelic frequencies of the IL-1Ra gene polymorphism between patients with gout and healthy control subjects. Furthermore, we did not detect any association of IL-1Ra genotype with the clinical and laboratory profiles in patients with gout.

CONCLUSION

The results from the present study suggest that the interleukin-1 receptor antagonist gene polymorphism is not a genetic marker of susceptibility to gout for Taiwanese. Furthermore, our study also suggests that the IL-1Ra gene polymorphism is unrelated to the clinical characteristics of gout.

Observation of a threshold enhancement in the plambda invariant-mass spectrum

An enhancement near the m(p)+M(Lambda) mass threshold is observed in the combined pLambda and pLambda invariant-mass spectrum from J/psi-->pK(-)Lambda;+c.c. decays. It can be fit with an S-wave Breit-Wigner resonance with a mass m=2075+/-12(stat)+/-5(syst) MeV and a width of Gamma=90+/-35(stat)+/-9(syst) MeV; it can also be fit with a P-wave Breit-Wigner resonance. Evidence for a similar enhancement is also observed in psi(')-->pK(-)Lambda;+c.c. decays. The analysis is based on samples of 5.8x10(7)J/psi and 1.4x10(7)psi(') decays accumulated in the BES II detector at the Beijing Electron-Positron Collider.

Observation of the decay psi(2S)-->K0SK0L

The decay psi(2S)-->K(0)(S)K(0)(L) is observed using psi(2S) data collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider; the branching fraction is determined to be B(psi(2S)-->K(0)(S)K(0)(L))=(5.24+/-0.47+/-0.48)x10(-5). Compared with J/psi-->K(0)(S)K(0)(L), the psi(2S) branching fraction is enhanced relative to the prediction of the perturbative QCD "12%" rule. The result, together with the branching fractions of psi(2S) decays to other pseudoscalar meson pairs (pi(+)pi(-) and K+K-), is used to investigate the relative phase between the three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.

Twenty-year follow-up of the Carpentier-Edwards standard porcine bioprosthesis in the Oriental population

AIM

The 20-year period long-term results of porcine bioprosthetic valve use are limited. In addition, the majority of these reports come from Western countries. Given the scanty information reported in Oriental countries, this study was therefore designed to examine 20-year long-term results in patients who received a Carpentier-Edwards porcine bioprosthetic valve in an effort to contribute further information on the long-term clinical performance of porcine prosthetic valves from a viewpoint of results in the Oriental population.

METHODS

From July 1979 to April 2001, 82 patients received valve replacement with a standard Carpentier-Edwards porcine valve. There were 40 men and 42 women with a mean age of 42.3+/-15.1 years (range 16 to 73 years). Follow-up time extended more than 20 years (mean 10.9+/-3.2 years, range 0.5 to 21.5 years ) for a total of 719.5 patient-years.

RESULTS

The overall operative mortality was 16.9% (14 of 83 procedures). At 5, 10, 15, and 20 years, the actuarial survival rate of patients was 71.7%, 66.9%, 55.5%, and 44.4%, respectively. Actuarial estimates of freedom from structural valvular deterioration (SVD) at 5, 10, 15, and 17 years were 96.3%, 64.0%, 24.3%, and 24.3%, respectively; from reoperation 96.3%, 64.5%, 24.5%, and 24.5%; from operated valvular endocarditis 96.8%, 92.6%, 92.6%, and 92.6%; and from overall thromboembolism 96.3%, 88.5%, 67.2%, and 52.2%. In normal sinus rhythm, actuarial estimates of freedom from thromboembolism at 5, 10, 15, and 17 years were 100.0%, 100.0%, 81.8%, and 81.8%, respectively. Whereas for those in patients with atrial fibrillation, the estimates of freedom from thromboembolism were 94.5%, 82.4%, 57.7%, and 38.5%.

CONCLUSION

This study demonstrates the very satisfactory 20-year period long-term performance of freedom from bleeding events, thromboembolism (except in patients with atrial fibrillation), and valvular endocarditis in Oriental patients undergoing replacement with a porcine valve. However, the remarkable rate of SVD and reoperation ensued at 6 years after bioprosthesis implanted which does not differ from the series reported from Western countries.

Effect of dietary rare earth elements on growth performance and blood parameters of rats

Rare earth elements (REE) have been shown to influence growth performance in animal production, especially in pigs. In the present study, the effect of oral administration of rare earth elements on growing rats was investigated. Pure LaCl3 or an REE mixture containing 38% of LaCl3, 52% of CeCl3, 3% of PrCl3 and 7% of chlorides of other REE were used at two different concentrations as supplements to the diets. Fifty male Wistar rats at 4 weeks of age were allotted to five experimental groups: a control group; a La-low group and a La-high group with 75 and 150 mg/kg LaCl3.6H2O, respectively; a REE-low and an REE-high group with 75 and 150 mg/kg REE mixture, respectively. The animals were housed in individual pens. Feed and water were provided ad libitum. After 18 days the oral supplementation of LaCl3.6H2O or of the REE mixture improved daily body weight gain (BWG) by up to 5 or 9% (p > 0.05), respectively. LaCl3.6H2O as well as the REE mixture had positive effects (p < 0.05) on feed conversion ratio (FCR) with a decreased ratio by up to 8 and 11%, respectively. Supplementation of REE also had clear effects on blood serum parameters. The activities of alkaline phosphatase (AP) and alanine amino transferase (ALT) increased significantly (p < 0.05). At the same time, blood glucose level decreased and blood creatine level increased significantly (p < 0.05). There was no significant difference in cholesterol, total protein, albumin and urea nitrogen among the groups. There was no significant difference in triglyceride level between the control and those REE groups, however, a significantly lower (p < 0.01) triglyceride level was found in the 150 mg/kg REE mixture group compared with that in 75 mg/kg REE mixture group and the 150 mg/kg LaCl3.6H2O group. The results suggest that oral supplementation of REE improves growth performance in rats as in pigs. In this respect, concentration and type of REE supplemented to the diets are two important factors herein.

Search for nu(e) from the sun at Super-Kamiokande-I

We present the results of a search for low energy nu(e) from the Sun using 1496 days of data from Super-Kamiokande-I. We observe no significant excess of events and set an upper limit for the conversion probability to nu(e) of the 8B solar neutrino. This conversion limit is 0.8% (90% C.L.) of the standard solar model's neutrino flux for total energy=8-20 MeV. We also set a flux limit for monochromatic nu(e) for E(nu(e))=10-17 MeV.

Healthcare-associated outbreak due to pan-drug resistant Acinetobacter baumannii in a surgical intensive care unit

Acinetobacter baumannii is ubiquitous and has recently become one of the most important healthcare-associated (HA) pathogens in hospitals. Infection caused by this organism often leads to significant morbidity and mortality. Outbreaks of pan-drug resistant Acinetobacter baumannii (PDRAB) have rarely been reported. During a two-month period, an outbreak of PDRAB colonization and infection affecting 7 patients occurred in our surgical intensive care unit (SICU). The colonized sites were respiratory tract (N = 7) and central venous catheter (N = 2). One of the patients had a surgical wound infection. Extensive environmental contamination was identified, including sites such as bed rails, bedside tables, surface of ventilators and infusion pump, water for nasogastric feeding and ventilator rinsing and sinks. All of the isolates were analysed by pulsed-field gel electrophoresis (PFGE) and showed an identical pattern. After use of strict cohort nursing, hand hygiene environmental cleaning, and replacement of a dysfunctional high-efficiency particulate air filter (HEPA), the outbreak was controlled.

Discrimination of Bacillus cereus and Bacillus thuringiensis with 16S rRNA and gyrB gene based PCR primers and sequencing of their annealing sites

AIMS

To evaluate the possibility for discrimination of Bacillus cereus and B. thuringiensis using 16S rRNA and gyrB gene based PCR methods, and to obtain the sequences of the primer annealing sites so that the PCR results may be explained.

METHODS AND RESULTS

Based on the sequence difference in the variable region (V1) of 16S rRNA and in the gyrB gene between B. cereus and B. thuringiensis, PCR primers specific to these Bacillus spp. were designed. When these primers were used to discriminate B. cereus and B. thuringiensis, six of 82 B. cereus strains were identified as B. thuringiensis while 67 of 73 B. thuringiensis strains were identified as B. cereus. Sequence analysis of the primer annealing sites showed that there is no clear-cut difference in the V1 region of 16S rRNA, and in the gyrB gene, between B. cereus and B. thuringiensis strains.

CONCLUSIONS

Although 16S rDNA based probes and gyrB gene based PCR primers have been suggested for the discrimination of B. cereus and B. thuringiensis strains, when a large number of Bacillus strains was tested, results showed that discrimination between B. cereus and B. thuringiensis is difficult. Therefore, to distinguish B. thuringiensis from B. cereus, a single feature, such as the presence of a parasporal crystal protein or cry gene, may sometimes be reliable.

SIGNIFICANCE AND IMPACT OF THE STUDY

Discrimination between B. cereus and B. thuringiensis is a challenging debate to which this paper makes a contribution.