GroEL protein of the Leptospira spp. interacts with host proteins and induces cytokines secretion on macrophages

BACKGROUND

Leptospirosis is a zoonotic disease caused by infection with spirochetes from Leptospira genus. It has been classified into at least 17 pathogenic species, with more than 250 serologic variants. This wide distribution may be a result of leptospiral ability to colonize the renal tubules of mammalian hosts, including humans, wildlife, and many domesticated animals. Previous studies showed that the expression of proteins belonging to the microbial heat shock protein (HSP) family is upregulated during infection and also during various stress stimuli. Several proteins of this family are known to have important roles in the infectious processes in other bacteria, but the role of HSPs in Leptospira spp. is poorly understood. In this study, we have evaluated the capacity of the protein GroEL, a member of HSP family, of interacting with host proteins and of stimulating the production of cytokines by macrophages.

RESULTS

The binding experiments demonstrated that the recombinant GroEL protein showed interaction with several host components in a dose-dependent manner. It was also observed that GroEL is a surface protein, and it is secreted extracellularly. Moreover, two cytokines (tumor necrosis factor-α and interleukin-6) were produced when macrophages cells were stimulated with this protein.

CONCLUSIONS

Our findings showed that GroEL protein may contribute to the adhesion of leptospires to host tissues and stimulate the production of proinflammatory cytokines during infection. These features might indicate an important role of GroEL in the pathogen-host interaction in the leptospirosis.

Neither Basic Life Support knowledge nor self-efficacy are predictive of skills among dental students

AIM

Basic life support (BLS) is considered a core competence for the graduating dentist. This study aimed to measure BLS knowledge, self-efficacy and skills of undergraduate dental students in Dublin.

METHODS

This study consisted of a cross-sectional survey measuring BLS knowledge and self-efficacy, accompanied by a directly observed BLS skills assessment in a subsample of respondents. Data were collected in January 2014. Bivariate correlations between descriptive and outcome variables (knowledge, self-efficacy and skills) were tested using Pearson's chi-square. We included knowledge and self-efficacy as predictor variables, along with other variables showing association, into a binary logistic regression model with BLS skills as the outcome measure.

RESULTS

One hundred and thirty-five students participated. Almost all (n = 133, 98.5%) participants had BLS training within the last 2 years. One hundred and four (77%) felt that they were capable of providing effective BLS (self-efficacy), whilst only 46 (34.1%) scored >80% of knowledge items correct. Amongst the skills (n = 85) subsample, 38.8% (n = 33) were found to pass the BLS skills assessment. Controlling for gender, age and skills assessor, the regression model did not identify a predictive relationship between knowledge or self-efficacy and BLS skills.

CONCLUSIONS

Neither knowledge nor self-efficacy was predictive of BLS skills. Dental students had low levels of knowledge and skills in BLS. Despite this, their confidence in their ability to perform BLS was high and did not predict actual competence. There is a need for additional hands-on training, focusing on self-efficacy and BLS skills, particularly the use of AED.

Breast nodularity and ulceration: diffuse dermal angiomatosis a corticosteroid responsive disease

Diffuse dermal angiomatosis of the breast (DDAB) is an uncommon ulcerative angiomatosis, which occurs in middle aged women with large pendulous breasts, a history of cigarette smoking, and risk factors for atherosclerosis. Based on its rarity, no well-defined therapeutic regimen has been elucidated. We report a case of DDAB in a woman with no history of smoking or radiographic evidence of occluded vasculature who presented with ulceration and pain-associated breast nodularity. She had a complete reproducible response to oral corticosteroids.

Dementia is associated with open-angle glaucoma: a population-based study

PURPOSE

Previous epidemiologic studies that focused on the association between open-angle glaucoma (OAG) and dementia showed inconsistent results. In the present study, we explored the association between OAG and dementia in an ethnic Chinese (i.e., Taiwanese) population using a population-based data set.

METHODS

We retrieved data on study subjects for this case-control study from the Longitudinal Health Insurance Database 2000. We identified 7770 patients who had a diagnosis of dementia as cases, and 7770 subjects matched in terms of sex and age, which were randomly extracted as controls. A conditional logistic regression conditioned on age group, sex, and index year was used to assess the association of dementia with previously diagnosed OAG among the sampled patients.

RESULTS

Of 15,540 patients, 1.70% had prior OAG, including 2.02% of the dementia group and 1.38% of the controls. After adjusting for patient socioeconomic characteristics and comorbid medical disorders, dementia patients were more likely to have had prior OAG than controls (odds ratio (OR): 1.44; 95% confidence interval (CI): 1.12-1.85; P<0.01). In addition, female dementia patients were more likely to have had prior OAG than controls (OR: 1.93; 95% CI: 1.35-2.77; P<0.001), whereas no statistical difference in prior OAG between male dementia patients and controls was found.

CONCLUSIONS

Female dementia patients were associated with a higher proportion of prior OAG than were the controls.

Intravitreous tissue plasminogen activator injection and pneumatic displacement in the management of submacular hemorrhage complicating scleral buckling procedures

PURPOSE

To evaluate the efficacy of recombinant tissue plasminogen activator (rTPA) and sulfur hexafluoride (SF6) in displacing submacular hemorrhage in patients who had scleral buckling procedures complicated by the development of submacular hemorrhage. Final visual acuity and complications of the procedures were evaluated.

METHODS

Sequential intravitreal injections of 50 microg rTPA in 0.1 mL and 0.4 cc SF6 were performed in eight patients who showed submacular hemorrhage 1 day after a scleral buckling procedure. The fundus was checked daily for 3 days after the injection of TPA and gas, and then was followed every week for 1 month and then every 2 months. Patients were observed for at least 6 months. Visual acuity and the status of complications were evaluated.

RESULTS

Submacular hemorrhage was totally or partially displaced extramacularly in all patients on the day after rTPA and SF6 injection. Vitreous hemorrhage was present in all patients. The retina was attached in all patients and no recurrent retinal detachment was noted. Visual acuity was improved at 6 months after treatment in all seven of the patients with macula-off retinal detachments compared to the preoperative visual acuity. The last patient who had a macula-sparing retinal detachment had decreased vision (20/25) at 6 months compared to preoperatively.

CONCLUSIONS

Recombinant tissue plasminogen activator and SF6 injection is an easy procedure that is less complicated than and as effective as internal drainage in patients with submacular hemorrhage developing as a complication of scleral buckling procedures.

Acute angle-closure glaucoma resulting from spontaneous hemorrhagic retinal detachment in age-related macular degeneration: case reports and literature review

PURPOSE

Acute angle-closure glaucoma resulting from massive subretinal hemorrhage is a rare and catastrophic complication in age-related macular degeneration. Anticoagulant usage had been strongly correlated with this complication in previously reported cases.

METHODS

Four patients (4 eyes), 3 men and 1 woman, developed angle-closure glaucoma with diffuse subretinal hemorrhage and total hemorrhagic retinal detachment.

RESULTS

Serial funduscopic examinations and echographic studies in 2 eyes showed that the blood gradually accumulated in the subretinal space. It took more than 10 days for the bleeding to build up to bullous hemorrhagic retinal detachment and secondary glaucoma. Anti-glaucomatous agents were given and sclerotomy was performed in 3 of the 4 patients. Phthisical changes were observed subsequently in these 3 eyes. The eye that received early drainage of blood was an exception, and a small degree of residual acuity was retained. Three of the 4 patients had diabetes mellitus, and hypertension and vascular diseases were also present in the same 3 patients.

CONCLUSIONS

Diabetes mellitus might be a predisposing factor for the impaired hemostasis. Anti-glaucomatous agents were of no effect in the management of intraocular pressure. Sclerotomy and drainage of blood help control intraocular pressure and relieve ocular pain. Poor final visual acuity is inevitable. However, phthisical changes might be prevented with early sclerotomy and drainage of blood.

Progression of hydroxychloroquine retinopathy after discontinuation of therapy: case report

Chloroquine and its derivative, hydroxychloroquine sulfate, have been used in treating malaria, dermatitides of systemic lupus erythematosus and rheumatoid arthritis. Hydroxychloroquine retinopathy is uncommon in Taiwan. Here we report a patient with hydroxychloroquine retinopathy which progressed even after discontinuation of hydroxychloroquine. A 42-year-old woman had systemic lupus erythematosus for twenty years. She had been treated with 200 to 400 mg of hydroxychloroquine per day (4 to 8 mg/kg of body weight/day) with a cumulative dose of 657 g. After bull's-eye maculopathy was found, hydroxychloroquine was discontinued. Her medical history revealed no chloroquine administration and no other systemic disease. Five years after cessation of the therapy, her visual acuity and visual fields continued to deteriorate. Ophthalmoscopic examination revealed the hydroxychloroquine retinopathy had advanced. To the best of our knowledge, the progression of hydroxychloroquine retinopathy after discontinuation of medications is a rare phenomenon. Regular ophthalmologic examinations should be performed for patients on hydroxychloroquine regimens because there is no satisfactory treatment for hydroxychloroquine retinal toxicity. Ophthalmologists, dermatologists and rheumatologists should monitor for ocular toxicity of hydroxychloroquine carefully.

Idiopathic polypoidal choroidal vasculopathy: case report

In 1990, Yannuzzi et al. introduced a new clinical entity, "idiopathic polypoidal choroidal vasculopathy" (IPCV). There is now a more-widespread worldwide recognition of a higher prevalence and importance of this disorder. We report on the first case of IPCV in Taiwan to our knowledge. A 63-year-old Taiwanese man complained of blurred vision in his right eye for 6 months. The anterior segment and vitreous were normal except for mild nuclear cataract changes. Fundus examination of the right eye showed hard exudates and multiple reddish-orange subretinal lesions in the macula. Fundus examination of the left eye was normal. Fluorescein angiography of the right eye showed multiple hyperfluorescent granular lesions in the macula. Subretinal leakage and pooling of fluorescein were present in the temporal macula. Indocyanine green angiography disclosed multiple aneurysmal dilations at the terminals of branching vascular networks. A hyperfluorescent aneurysmal lesion corresponding to the reddish-orange nodule was observed ophthalmoscopically, and a granular lesion was observed in fluorescein angiography. Focal retinal photocoagulation was applied to the leakage area identified with fluorescein angiography. Two months after photocoagulation was performed, the subretinal fluid had gradually resolved, but a new leakage in the macula was demonstrated with fluorescein angiography. His best corrected vision in the right eye was stable.

Bilateral diffuse uveal melanocytic proliferation in a woman with uterine leiomyoma: case report

Bilateral diffuse uveal melanocytic proliferation (BDUMP) associated with systemic carcinoma is a rare paraneoplastic syndrome. It was reported to be associated with primary carcinomas of the lung, ovary, colon, gall bladder, esophagus, pancreas, uterus, and cervix. We report a case of BDUMP that occurred in a woman with cervical leiomyoma. The 79-year-old woman experienced bilateral progressive visual loss to hand motion within 2 weeks. Fundus examination showed bilateral exudative retinal detachment and multiple oval red patches. Echographic study showed diffuse thickening of the uveal tracts. Fluorescein angiography showed multiple patches of window defect without late leakage, which was correlated with the oval red patches. After screening for tumor markers and meticulous examinations, an elevated serum level of CA-125 was noted. The only neoplasm found in this patient was a cervical leiomyoma, which has never been reported to be associated with BDUMP. One month after the onset of symptoms, accidental head injury due to poor vision led to right parietal intracerebral hemorrhage and left hemiplegia. Prompt diagnosis of this paraneoplastic syndrome is important to discover the underlying malignancy in patients with no history of cancer. For those cases without malignant neoplasm, attention should be directed to the disability caused by the severe visual loss, which led to accidental head injury and intracerebral hemorrhage in this case.

Perfluorodecalin condensation on posterior surface of lens capsule and corneal endothelium during vitrectomy

BACKGROUND

High-density vitreous substitutes, including perfluorodecalin, are widely used in current vitreoretinal surgery. We report 4 cases of perfluorodecalin condensation on the posterior capsule of the lens or corneal endothelium during vitrectomy. To the best of our knowledge, no such phenomenon has ever been reported.

METHODS

This study consisted of 4 patients with retinal detachment and large retinal tears. All patients were men. All of the patients underwent pars plana vitrectomy, perfluorodecalin injection, endolaser retinopexy and air-fluid exchange. Two patients received additional surgery for scleral buckling.

RESULTS

Perfluorodecalin condensation was observed on the posterior surface of the lens capsule in one phakic patient and on the endothelium in three aphakic patients during vitrectomy. The condensation obscured the image of the fundus and made air-fluid exchange difficult. The condensation could be dissipated by first removing the perfluorodecalin as completely as possible, and then by lowering the intraocular pressure below the vapor pressure of perfluorodecalin.

CONCLUSIONS

Perfluorodecalin condensation may occur when perfluorodecalin is not properly used. To avoid forming condensation, high-density vitreous substitutes should never be injected into eyes that are completely air-filled, prolonged air-fluid exchanges should be avoided, and the intraocular pressure should always be kept at a higher level during air-fluid exchange.

Induction of positive cooperativity by amino acid replacements within the C-terminal domain of Penicillium chrysogenum ATP sulfurylase

ATP sulfurylase from Penicillium chrysogenum is an allosteric enzyme in which Cys-509 is critical for maintaining the R state. Cys-509 is located in a C-terminal domain that is 42% identical to the conserved core of adenosine 5'-phosphosulfate (adenylylsulfate) (APS) kinase. This domain is believed to provide the binding site for the allosteric effector, 3'-phosphoadenosine 5'-phosphosulfate (PAPS). Replacement of Cys-509 with either Tyr or Ser destabilizes the R state, resulting in an enzyme that is intrinsically cooperative at pH 8 in the absence of PAPS. The kinetics of C509Y resemble those of the wild type enzyme in which Cys-509 has been covalently modified. The kinetics of C509S resemble those of the wild type enzyme in the presence of PAPS. It is likely that the negative charge on the Cys-509 side chain helps to stabilize the R state. Treatment of the enzyme with a low level of trypsin results in cleavage at Lys-527, a residue that lies in a region analogous to a PAPS motif-containing mobile loop of true APS kinase. Both mutant enzymes were cleaved more rapidly than the wild type enzyme, suggesting that movement of the mobile loop occurs during the R to T transition.

Prehospital consideration of sildenafil-nitrate interactions

OBJECTIVE

To determine whether paramedics and on-line physicians screen patients for use of sildenafil citrate (Viagra) prior to prehospital administration of nitrates.

METHODS

A prospective, observational study was performed over a one-month period in three EMS systems. Consecutive radio communications between on-line physicians and paramedics concerning male patients with cardiac complaints were monitored. Investigators observed the frequency with which on-line physicians screened for sildenafil use prior to ordering nitrates. After observation of the radio communications was completed, a written survey was distributed to all paramedics in the three EMS systems.

RESULTS

Seventy-six physician-paramedic interactions were monitored. Nitrates were ordered by on-line physicians in 56 cases. No paramedic reported sildenafil use/nonuse, and no on-line physician inquired about the patient's potential use of the drug. Only half of the surveyed paramedics reported that they routinely screen for sildenafil use, and approximately a fourth reported that its use would not alter their management of chest pain patients.

CONCLUSION

In this study, on-line physicians in three EMS settings did not screen for sildenafil use prior to ordering nitrates. While some paramedics do screen for sildenafil use, practice patterns among paramedics in these three systems were inconsistent.

Failure of adjunctive bicarbonate to improve outcome in severe pediatric diabetic ketoacidosis

STUDY OBJECTIVE

Although adjunctive intravenous bicarbonate therapy is commonly recommended for children with severe diabetic ketoacidosis (DKA), no studies assessing clinical outcome with this therapy have ever been performed. Our objective was to determine whether bicarbonate therapy influenced outcome for pediatric DKA.

METHODS

The study was a retrospective consecutive case series of 147 admissions for severe DKA (initial pH < or = 7.15 and glucose concentration > or = 300 mg/dL [16.7 mmol/L]) in 106 children during a 16-year period at a tertiary university medical center. Descriptive statistics were applied to the 147 admissions. The first patient admitted with DKA was then selected for each of the 106 children, and clinical and laboratory data were compared between subjects who did and did not receive bicarbonate. Multivariate and matched pair analyses were performed to control potentially confounding variables.

RESULTS

Fifty-seven of the 147 patients admitted with DKA (39%) were successfully treated without bicarbonate, including 9 with a pH of 7.00 or less and one with a pH of 6.73. The frequency of complications was comparable between bicarbonate and nonbicarbonate groups (4% versus 2%, P = 1.00). The mean duration of hospitalization for children receiving bicarbonate was 23% (16 hours) longer than children who did not receive bicarbonate in the multivariate analysis (P = .07) and 37% (22 hours) longer in the matched pair analysis (P = .01). The mean rate of metabolic recovery by three distinct measures was similar between groups, and the sample had 80% power to detect differences of 14% to 29% in these measures.

CONCLUSION

We found no evidence that adjunctive bicarbonate improved clinical outcome in children with severe DKA. The rate of metabolic recovery and complications were similar in patients treated with and without bicarbonate, and prolonged hospitalizations were noted in the bicarbonate group. We conclude that adjunctive bicarbonate is unnecessary and potentially disadvantageous in severe pediatric DKA.