Reprogramming microbes to be pathogen-seeking killers

Recent examples of new genetic circuits that enable cells to acquire biosynthetic capabilities, such as specific pathogen killing, present an attractive therapeutic application of synthetic biology. Herein, we demonstrate a novel genetic circuit that reprograms Escherichia coli to specifically recognize, migrate toward, and eradicate both dispersed and biofilm-encased pathogenic Pseudomonas aeruginosa cells. The reprogrammed E. coli degraded the mature biofilm matrix and killed the latent cells encapsulated within by expressing and secreting the antimicrobial peptide microcin S and the nuclease DNaseI upon the detection of quorum sensing molecules naturally secreted by P. aeruginosa. Furthermore, the reprogrammed E. coli exhibited directed motility toward the pathogen through regulated expression of CheZ in response to the quorum sensing molecules. By integrating the pathogen-directed motility with the dual antimicrobial activity in E. coli, we achieved signifincantly improved killing activity against planktonic and mature biofilm cells due to target localization, thus creating an active pathogen seeking killer E. coli.

Visualizing the perturbation of cellular cyclic di-GMP levels in bacterial cells

Cyclic di-GMP (c-di-GMP) has emerged as a prominent intracellular messenger that coordinates biofilm formation and pathogenicity in many bacterial species. Developing genetically encoded biosensors for c-di-GMP will help us understand how bacterial cells respond to environmental changes via the modulation of cellular c-di-GMP levels. Here we report the design of two genetically encoded c-di-GMP fluorescent biosensors with complementary dynamic ranges. By using the biosensors, we found that several compounds known to promote biofilm dispersal trigger a decline in c-di-GMP levels in Escherichia coli cells. In contrast, cellular c-di-GMP levels were elevated when the bacterial cells were treated with subinhibitory concentrations of biofilm-promoting antibiotics. The biosensors also revealed that E. coli cells engulfed by macrophages exhibit lower c-di-GMP levels, most likely as a response to the enormous pressures of survival during phagocytosis.

Rational design of fluorescent biosensor for cyclic di-GMP

Messenger bagged: The design of a fluorophore-labeled protein biosensor for the bacterial messenger cyclic di-GMP is described. The biosensor responds to c-di-GMP with sub-micromolar sensitivity in a real-time fashion. The biosensor can be used for enzyme assays for diguanylate cyclases and c-di-GMP phosphodiesterases as well as the high-throughput screening of inhibitors.

One-Stage Reconstruction of the Penis with Free Skin Flap: Report of Three Cases

Three cases of penile defect of varying extent were reconstructed with free skin flaps from the forearm based on the radial artery. In two cases, part of the forearm flap was used to reconstruct the urethra, and the rest of the flap to reconstruct the corpus penis. A piece of autogenous cartilage was then inserted between the two layers. All procedures were completed in a one-stage operation. In the third case, a free skin graft was used for urethral reconstruction. Surgery in all three cases was successful, providing a penis of acceptable appearance as well as excellent urinary function.

CNS aspergillosis with mycotic aneurysm, cerebral granuloma and infarction

We are reporting a case of an immunocompromised patient with invasive aspergillosis (IA) who developed aspergillotic granulomas and a mycotic aneurysm of the superior cerebellar artery. The route of infection of the central nervous system (CNS) was hematogenous spread from a pulmonary focus. IA was detected with the Galactomannan (GM) technique. However, despite treatment with amphotericin B, progressive involvement of the vessel wall occurred causing fatal subarachnoid hemorrhage and massive brainstem and cerebellar infarction. This case provides pathologic-imaging correlation of one of the most devastating types of fungal involvement affecting the CNS with a fungal aneurysm. Finally the literature regarding the pathogenetic, and diagnostic investigations and the management of CNS aspergillosis is reviewed.

Idiopathic segmental infarction of right sided greater omentum. Case report and review of the literature

Idiopathic right segmental infarction of the greater omentum is an uncommon cause of acute abdomen. The aetiology is still unclear and the symptoms mimick acute appendicitis. We present a case of a 77-year old man with unsignificant medical history, admitted with an acute abdomen, in whom the clinical diagnosis was unknown until an infarcted segment of right side of the greater omentum was found at laparoscopy, and successfully resected. As the aetiology is unknown, we highlighted some of the possible theories, and emphasize the importance of considering omental infarction in the differential diagnosis of right iliac fossa syndrome in cases of acute abdomen.

Clinical PET imaging--an Asian perspective

Positron emission tomography (PET) has entered a new phase of development since a major technological breakthrough in 2000. Combined with computed tomography (CT), the second-generation PET-CT scanner is now able to obtain both functional and anatomical information of the whole body from a single study. Its application in oncology has become one of the standard imaging modalities in diagnosis, staging and monitoring therapeutic efficacy. It is well known that the Asian and Western populations have their own characteristic disease spectrum and cancer incidence. Although changes in diet and life-style have narrowed the differences in the last decade, there remains moderate divergence and disparities in cancer pattern and priority of resource allocation in different countries. It is known that F-18 fluorodeoxyglucose (FDG) is the most widely used radiopharmaceutical in PET imaging and it has been confirmed valuable in a variety of cancer types such as lung, colorectum, oesophagus, head and neck (including nasopharyngeal carcinoma), breast, pancreas, lymphoma, melanoma, cholangiocarcinoma and many types of sarcoma. Some cancer types, however, are less sensitive to FDG-PET detection and these include hepatocellular carcinoma, urological carcinoma, gastric malignancy, mucinous and clear-cell gastrointestinal tumours, neuroendocrine tumours and well-differentiated thyroid cancers. Some of these less sensitive cancer types are more prevalent in the Asian population than the Euro-American population and are, therefore, more frequently encountered as false negative cases in FDG-PET imaging. On the other hand, Asian countries are more prevalent in diseases such as tuberculosis and the chance of having false positive FDG-PET cases is higher than the Euro-American countries in the evaluation of lung and other cancers. From the Asian perspective, we are more susceptible to having a higher chance of both false negative and false positive FDG-PET cases. Thus, there is a stronger emphasis of research on new drugs to overcome the limitations of FDG. The use of PET imaging as a diagnostic tool has gained wide acceptance in Asia during the past few years and its clinical utility is expected to continue to rise. More research on other PET radiopharmaceuticals should therefore be given a higher priority along side with the maturation of scanning technology.

Suppurative salmonella thyroiditis in a patient with chronic lymphocytic leukemia

We describe an 82-year-old man with undiagnosed chronic lymphocytic leukemia (CLL) who presented with acute swelling of the thyroid goiter. Subsequent thyroid aspirate and blood culture yielded group B Salmonella thyroid abscess with septicemia. Infectious complications are the major cause of morbidity and mortality in patients with CLL since most of them can be timely detected and few can arise from innocent-looking lesions.

Rhegmatogenous retinal detachment in morning glory syndrome pathogenesis and treatment

We report a case of morning glory syndrome with retinal detachment. A slit-like retinal break at the edge of the excavated disc anomaly provided a direct communication between the subretinal space and the vitreous cavity. Retinal reattachment and useful vision was achieved after a single procedure of vitrectomy and gas tamponade. We believe that identification of the retinal break, removal of epipapillary fibroglial tissue and its traction force, the avoidance of perfluorocarbon liquid and the appropriate use of long-acting gas as endotamponade, all contributed to the favorable outcome. This is more evidence supporting the rhegmatogenous theory of retinal detachment in morning glory syndrome. A literature review of the clinical presentations and treatments of similar cases is included.

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.

Reduction of subretinal fluid after preoperative immobilization of the eyes with rhegmatogenous retinal detachment

BACKGROUND

Bullous retinal detachment may be difficult to handle with higher operative complications. Preoperative immobilization of the eyes might reduce subretinal fluid and facilitate surgical procedures. Factors influencing subretinal fluid absorption were analyzed.

METHODS

Twenty-eight eyes with primary rhegmatogenous retinal detachment with preoperative binocular patching and complete bed rest for at least 12 hours were enrolled. Ultrasonography was performed before and after immobilization to estimate the reduction in subretinal fluid.

RESULTS

The amount of reduction diverged in cases with an average of a 17.1% decrease in the maximal height of detachment. Retinal detachments in patients with smaller breaks and without vitreal traction or chronicity showed more significant reduction of subretinal fluid than did those patients with larger breaks and with vitreal traction or chronicity. On the other hand, break shape, height of retinal detachment, age, and gender had no obvious effect on subretinal fluid change.

CONCLUSIONS

Preoperative immobilization of the eyes reduces the subretinal fluid in selected cases, which can decrease operative complications. Break size, vitreal traction, and chronicity are important factors affecting the absorption of subretinal fluid.

Adult lymphoblastic lymphoma in Taiwan: an analysis of treatment results of 26 patients

Lymphoblastic lymphoma (LBL) frequently affects young adults and usually presents with a mediastinal mass as well as bone marrow involvement. Although the frequency of LBL in the Far East is higher than that of Western countries, no reports regarding treatment of this disease have as yet been reported. We herein report our treatment experience and verify the efficacy of the Stanford/Northern California Oncology Group (NCOG) protocol for this disease and recommend treatment strategies for LBL patients. We retrospectively reviewed the medical records of adult LBL patients treated in our hospital from 1986 to 1996. Twenty-seven patients were diagnosed to have LBL. These patients' ages ranged from 17 to 73 years old with a median of 23. Nineteen patients had an initial stage IV disease. Of the 23 cases in which immunological studies were performed, 20 proved to be of T cell lineage, 1 of B cell type, and the other 2 lacked both T and B markers. Three major chemotherapeutic regimens including prednisone, methotrexate, doxorubicin, cyclophosphamide, etoposide-mechlorethamine, vincristine, procarbazine, prednisone (ProMACE-MOPP), cyclophosphamide, hydroxydaunomycin, vincristine, prednisone (CHOP), and the Stanford/NCOG protocol were used to treat 3, 6, and 15 patients, respectively. Two other patients were treated with two different chemotherapeutic regimens, respectively. One patient was excluded for analysis because of initial treatment by surgery. The complete response (CR) rates with ProMACE-MOPP, CHOP, and the Stanford/NCOG regimens were 0%, 17%, 80% and median overall survival 9, 8.5, and 15 months, respectively. Five patients with stage II-III diseases achieved long-term disease-free survival of 11-36 months with the Stanford/NCOG protocol with a median follow-up of 24 months. Four patients in late stage or relapse received allogeneic bone marrow transplantation (BMT). Two of them obtained long-term disease-free survival. Two other patients in CR were treated with high-dose chemotherapy (HDCT) supported with autologous BMT and peripheral blood stem cell transplantation (PBSCT), respectively. The patient receiving HDCT with autologous PBSCT died of LBL relapse 6 months after transplantation. The other patient undergoing HDCT with autologous BMT died of fulminant hepatitis 5.5 months after transplantation. The median overall survival of all these 26 patients was 12 months. B symptoms and treatment without the Stanford/NCOG protocol were found to have significantly negative impacts on both patients' overall and progression-free survivals. Our results suggest that the Stanford/NCOG protocol may be an effective chemotherapy for adult LBL and may provide long-term remission for patients in an early stage of disease. For those patients with LBL in an advanced stage or in relapse, HDCT with allogeneic or autologous BMT is probably the treatment of choice.

Impact of open lung biopsy for undiagnosed pulmonary infiltrates in patients with hematological malignancies

Pulmonary complications are frequently encountered in patients with hematological malignancy. The optimal therapeutic decision including open lung biopsy (OLB) for such patients is uncertain. We herein examine the clinical impact of OLB on these patients. Seven patients with progressively diffuse pulmonary infiltrates despite aggressive medical treatment were examined. The underlying diseases, prior treatment for presumptive pneumonia, the change in therapeutic approach after operation, and clinical outcome were reviewed retrospectively. Diffuse pulmonary infiltrates were caused by infection in two patients and by noninfectious etiology such as alveolar proteinosis, idiopathic interstitial pneumonitis, leukemic involvement, and drug-induced alveolar damage in the others. Four patients who had serious underlying hematologic diseases such as myelodysplastic syndrome, acute and chronic myeloid leukemia, and T cell lymphoma died. Three patients with acute lymphoid leukemia survived. In two of these three, change of therapeutic strategies after OLB was created for the survival. OLB in patients with hematological malignancy may be useful in selected patients with a treatable hematologic disease who have treatable underlying causes of the pulmonary infiltrate.

Enhancing the hypotensive effect and diminishing the cytolytic activity of hornet mastoparan B by D-amino acid substitution

Mastoparan B (MP-B) is a cationic tetradecapeptide (LKLKSIVSWAKKVL-CONH(2)) isolated from the venom of the Taiwan hornet Vespa basalis. Unlike other vespid mastoparans, the peptide is capable of inducing short-term hypotension and causes hemolysis in animals. This study was aimed to find out MP-B analogs that possess higher hypotensive potency with the least lytic action by D-amino acid substitution, especially at lysine (Lys) residues. The synthetic MP-B isomer in which Lys(2) was replaced by D-Lys showed a significant decrease in both hemolytic and hypotensive activities. Substitution of Lys(4) by D-Lys in MP-B also caused a marked reduction of hemolytic activity, but its hypotensive action was only slightly affected. However, when Lys(11,12) were replaced by D-Lys, the resulting isomer ([D-Lys(11,12)]MP-B) exhibited a higher hypotensive activity with negligible hemolytic activity as compared with the native peptide. The D-antipot of MP-B in which all amino acid residues were replaced by D-isomers showed the highest hypotensive activity with a hemolytic activity about 1/5 that of MP-B. The results reveal that D-Lys substitution at the N-terminus of MP-B (Lys(2,4)) causes decreases in both hypotensive and hemolytic activities, while D-Lys substitution at the C-terminus (Lys(11,12)) leads to a significant increase in hypotensive activity of MP-B with a remarkable decrease in hemolytic activity. The hypotensive effect of [D-Lys(11,12)]MP-B was more prominent on spontaneously hypertensive rats. At a proper dose (0.3mg/kg) the peptide could reduce the high blood pressure (approximately 180 mmHg) of the rat to a normal level (approximately 120 mmHg) for more than 3h. [D-Lys(11,12)]MP-B which possesses a potent hypotensive action with the least cytolytic side effect is the best MP-B analog for studying the mechanism of cardiovascular inhibition by MP-B and could be useful as a hypotensive agent in hypertension crisis.

Ocular ischemic syndrome

BACKGROUND

The purpose of this study was to investigate the clinical features and management of ocular ischemic syndrome (OIS) and factors influencing its development.

METHODS

Ten patients (12 eyes) with OIS underwent detailed medical and ocular histories, complete ophthalmic evaluation including fluorescein angiography, internal carotid artery evaluation by duplex ultrasonography, and management. The following outcome measures were considered: visual acuity, anterior segment neovascularization, lens status, retinal and choroidal changes, and carotid artery stenosis or occlusion.

RESULTS

The mean age of the patients was 63 +/- 8 years. Presenting visual symptoms included gradual (82.5%) or sudden (17.5%) onset of vision loss. At initial visit, eyes with OIS had visual acuity less than or equal to counting fingers in 50%, iris neovascularization in 58%, and neovascular glaucoma in 42%. Initially associated systemic diseases in these patients included arterial hypertension (60%), diabetes mellitus (40%), coronary artery disease (20%), previous stroke (30%) and hemodialysis (10%). Complete occlusion or severe occlusion (70-99%) of the internal carotid artery was seen in 75% on the side of OIS. Panretinal photocoagulation did not prevent OIS from progressing but vitreous hemorrhage and rubeosis iris regressed. Carotid endarterectomy had some benefit in stabilizing or improving vision in patients with OIS.

CONCLUSION

OIS has a poor visual prognosis. It is imperative that the clinician be aware of the signs and symptoms of carotid disease in order to facilitate prompt diagnosis and appropriate referral, because OIS may be the presenting sign of serious ischemic cerebrovascular and ischemic heart disease.

Expression profiles of ErbB family receptors and prognosis in primary transitional cell carcinoma of the urinary bladder

In vitro experiments have demonstrated that epidermal growth factor (EGF)-related peptides activate distinct subsets of ErbB receptors and differ in their biological activities. The implications of cross-talk among ErbB family receptors in human cancer, however, remain to be clarified. This cohort study was performed to examine the expression patterns of ErbB receptors by immunohistochemistry in primary human bladder cancer (n = 245) and compared with conventional biological indicators for their prognostic significance. Expression of individual EGF receptor (EGFR) and ErbB2, ErbB3, or ErbB4 receptors was detected in 72.2, 44.5, 56.3, and 29.8% of bladder cancer cases, respectively. Expression of two of the receptors varied from 14.7 to 42.4%, of three of the receptors between 11.0 and 22.0%, and of all four of the ErbB receptors by 8.6%. Important indicators in association with patient survival were tumor staging (P = 0.017), ErbB2 (P = 0.018), EGFR-ErbB2 (P = 0.023), and ErbB2-ErbB3 (P = 0.042). In the subset of grade-2 tumors, EGFR-ErbB2-ErbB3 and EGFR-ErbB2 predicted the development of second recurrence (P = 0.026 and 0.039, respectively), and ErbB2-ErbB3 tended to correlate with patient survival (P = 0.09). The results indicate that a combination of EGFR, ErbB2, and ErbB3 expression profile may be a better prognostic indicator than any family member alone. Given that ErbB2 is the preferred coexpression partner of ErbB family members, expression of other ErbB receptors may significantly affect the prognostic implication of ErbB2 for bladder cancer patients.

Autologous peripheral blood stem cell transplantation for patients with malignancies: the Tri-Service General Hospital experience

BACKGROUND

High-dose chemotherapy/radiotherapy followed by autologous peripheral blood stem cells transplantation (APBSCT) can be used to treat chemosensitive malignant diseases. We retrospectively studied the APBSCT treatment efficacy and safety of patients at Tri-Service General Hospital (TSGH).

METHODS

From January 1994 to March 2000, 11 patients were treated with high doses of chemotherapy/radiotherapy followed by APBSCT. Nine patients were male and 2 were female. The median age was 26 years, with a range of 21 to 51. There were 7 acute myeloid leukemia (AML), 3 non-Hodgkin's lymphoma (NHL) and 1 ovarian cancer. All patients received both chemotherapy and granulocyte-colony stimulating factor to mobilize hematopoietic stem cells, and the most commonly used conditioning regimen was combined chemotherapy with Busulfan and Cyclophosphamide.

RESULTS

The median numbers of infused mononuclear and CD34+ cells were 3.19 x 10(8)/kg and 9.2 x 10(6)/kg, respectively. Nine of the 11 patients engrafted successfully, but 2 patients with AML failed to engraft. The median times of WBC recovery (ANC > or = 500/uL) and platelet recovery (> or = 20 x 10(3)/uL) were 13 and 16 days, respectively. Four patients with AML survived after APBSCT and two of them were alive and disease-free for 36 and 51 months, respectively. One patient with AML and 3 patients with NHL died of relapse, and one patient with ovarian cancer was alive but with disease at 50 months.

CONCLUSIONS

For patients with AML, APBSCT may be an alternative, safe and useful treatment modality. Further strategies for reducing relapse in lymphoma patients merit further investigation.

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.