Bacterial delivery of a novel cytolysin to hypoxic areas of solid tumors

The efficacy of current anti-cancer gene therapies is limited by the inability of gene vectors to penetrate the poorly vascularized, hypoxic regions of tumors, leaving these sites untreated. We describe a new approach for targeting gene therapy to these sites, which employs an attenuated strain of the non-pathogenic bacterium, Salmonella typhimurium, carrying an exogenous (that is, reporter or therapeutic) gene under the regulation of a new, highly hypoxia-inducible promoter (FF+20(*)). This bacterial vector was seen to rapidly migrate into, and thrive in, hypoxic areas of both mammary tumor spheroids grown in vitro and orthotopic mammary tumors after systemic injection. Using the reporter gene construct, FF+20(*)-lacZ, we show that bacterial expression of high levels of beta-galactosidase occurred only in hypoxic/necrotic sites of spheroids and tumors. We then replaced the reporter gene with one encoding a novel cytotoxic protein (HlyE) and showed that this was also expressed by bacteria only in hypoxic regions of murine mammary tumors. This resulted in a marked increase in tumor necrosis and reduced tumor growth. Our system represents a promising new strategy for delivering gene therapy to poorly vascularized regions of tumors and shows, for the first time, the efficacy of HlyE as an anti-tumor agent.

Predictors of disease-free survival in rectal cancer patients undergoing curative proctectomy

OBJECTIVE

To identify the factors that affect the disease-free survival (DFS) of rectal cancer patients.

METHOD

Patients from an IRB approved rectal cancer database were reviewed (1990-2000). All patients underwent either abdominoperineal resection or low anterior resection using total mesorectal excision with curative intent. Univariate and multivariate analyses were performed to analyse the factors that influenced DFS.

RESULTS

A total of 304 patients were reviewed (mean age 64, 52% male). Seventy-seven per cent of patients received neoadjuvant therapy (28.6% short-course radiation therapy (RT), 35.5% long-course RT, 12.5% chemo-RT). The radial margin was involved with tumour in 5.2% of patients (final pathology). The overall survival rate was 85.2% with a mean follow-up time of 33 +/- 26 months. The mean time to death was 34.8 +/- 26.8 months. Local recurrence (+/- distant recurrence) occurred in 4%. Anastomotic leaks occurred in 3.6% of patients. Overall pathologic stage, pathologic T stage, nodal status, the use of adjuvant chemotherapy, tumour fixation, involvement of the radial margin, the presence of mucin, and lymphatic and perineural invasion (PNI) were predictors of DFS by univariate analysis. Of note, anastomotic leaks and obstructing cancers did not influence DFS. Using multivariate analysis with backward elimination, overall pathologic stage, radial margin status, adjuvant chemotherapy, and PNI predicted the DFS.

CONCLUSION

Major predictors of DFS in rectal cancer are the overall pathologic stage, adjuvant chemotherapy, radial margin status and PNI. Radial margin status may be a marker of tumour aggressiveness and should be considered in deciding on adjuvant chemotherapy.

Effect of 308 nm excimer laser irradiation on retinal pigment epithelium cell viability in vitro

BACKGROUND

Translocation of an autologous retinal pigment epithelium (RPE) sheet under the macula is currently under investigation as a treatment for exudative AMD. Excimer laser-assisted RPE sheet translocation (EST) employs intraocular excimer ablation of excess graft choroidal tissue as a measure to enhance RPE sheet functionality. This study assessed potential adverse effects of excimer irradiation on RPE cells in vitro.

METHODS

Human RPE cells (ARPE-19) received 308 nm XeCl excimer laser treatment or 311-312 nm UV-B irradiation. Cell death was visualised with Trypan Blue and quantified by LDH release assay. Apoptosis was detected by DNA fragmentation assay.

RESULTS

Laser treatment of 0.175-0.25 J/cm(2) resulted in delayed cell death within 48 h. Time course and dose response paralleled the effect of UV-B irradiation. Cytotoxicity was mediated by apoptosis. Human choroid/Bruch membrane tissue sheets covering the cells during laser irradiation reduced cytotoxicity by 87-95%.

CONCLUSION

Cultured human RPE cells are susceptible to apoptotic cell death induced by 308 nm excimer laser irradiation. Absorption by choroid/Bruch membrane tissue can largely prevent the cytotoxic effect. In clinical application, the residual adverse effect of laser ablation on graft RPE cell viability needs to be outweighed by potential advantageous effects on graft survival and functionality to allow for a sensible application of excimer ablation in RPE translocation surgery.

Twenty-year survivors of heart transplantation at Stanford University

Human heart transplantation started 40 years ago. Medical records of all cardiac transplants performed at Stanford were reviewed. A total of 1446 heart transplantations have been performed between January 1968 and December 2007 with an increase of 1-year survival from 43.1% to 90.2%. Sixty patients who were transplanted between 1968 and 1987 were identified who survived at least 20 years. Twenty-year survivors had a mean age at transplant of 29.4 +/- 13.6 years. Rejection-free and infection-free 1-year survivals were 14.3% and 18.8%, respectively. At their last follow-up, 86.7% of long-term survivors were treated for hypertension, 28.3% showed chronic renal dysfunction, 6.7% required hemodialysis, 10% were status postkidney transplantation, 13.3% were treated for diabetes mellitus, 36.7% had a history of malignancy and 43.3% had evidence of allograft vasculopathy. The half-life conditional on survival to 20 years was 28.1 years. Eleven patients received a second heart transplant after 11.9 +/- 8.0 years. The most common causes of death were allograft vasculopathy (56.3%) and nonlymphoid malignancy (25.0%). Twenty-year survival was achieved in 12.5% of patients transplanted before 1988. Although still associated with considerable morbidity, long-term survival is expected to occur at much higher rates in the future due to major advances in the field over the past decade.

[Increased dietary intake of omega-3-PUFA reduces pathological retinal angiogenesis]

According to a recent publication in Nature Medicine an increased dietary intake of omega-3-polyunsaturated fatty acids (PUFA) may protect against the development and progression of retinal neovascularization. The study conducted by L. Smith et al. of the Children's Hospital Boston attracts world-wide attention. In a mouse model of oxygen-induced retinopathy the researchers were able to demonstrate that neonatal mice kept on a "Japanese diet" (i.e. rich in omega-3-PUFA) developed about 50% less retinal neovascularization as compared to mice kept on a "Western diet" (rich in omega-6-PUFA). The results are now being followed-up by a clinical study with the aim to investigate whether prematurely born infants with a high risk of developing ROP may benefit from a diet supplemented with omega-3-PUFA. In addition, the AREDS2-Study which commenced in October 2006 is examining the role of omega-3-PUFA in the development and progression of age-related macular degeneration.

Wernicke's encephalopathy after laparoscopic cardiomyotomy for achalasia

Achalasia is an incurable neuromuscular disorder of the esophagus, resulting from destruction of the esophageal myenteric plexus. This leads to aperistalsis and failure of the lower esophageal sphincter to relax after swallowing. Symptoms of achalasia are gradual in onset and include dysphagia, regurgitation, and weight loss. Severe malnutrition can ensue. Wernicke's encephalopathy (WE) is a serious, potentially fatal, neurologic disorder caused by thiamine deficiency (vitamin B(1)), classically described as presenting with a triad of ocular abnormalities, ataxia, and confusion. The incidence is uncertain, and many cases likely go unrecognized. It is usually diagnosed in the alcoholic population. We describe its onset after the successful surgical treatment of achalasia.

Effect on MRSA transmission of rapid PCR testing of patients admitted to critical care

We report a significant reduction in the rate of meticillin-resistant Staphylococcus aureus (MRSA) transmission on a critical care unit when admission screening by culture was replaced with a same-day polymerase chain reaction (PCR) test. This was an observational cohort study, set in a 19-bed mixed medical and surgical adult critical care unit in southwest England. We studied 1305 patients admitted between April 2005 and February 2006. Standard MRSA culture methods were used to screen 612 patients between April 2005 and August 2005, and the IDI MRSA PCR test was used to screen 693 patients between September 2005 and February 2006. Standard infection control precautions were instituted when positive results were obtained by either method. Outcome measures included carriage rate, turnaround time for results and rate of subsequent MRSA transmission on the unit. The overall carriage rate on admission to the unit was 7.0%. Culture results were available in three working days, PCR results within one working day. The mean incidence of MRSA transmission was 13.89/1000 patient days during the culture phase and 4.9/1000 patient days during the PCR phase (relative risk reduction 0.65, 95% CI 0.28-1.07). PCR screening for MRSA on admission to critical care units is feasible in routine clinical practice, provides quicker results than culture-based screening and is associated with a significant reduction in subsequent MRSA transmission.

Levetiracetam in pregnancy: Preliminary experience from the UK Epilepsy and Pregnancy Register

It is not known whether the antiepileptic drug (AED) levetiracetam can be used safely in human pregnancy. As part of a study to determine the risks of major congenital malformations (MCMs) for infants exposed to AEDs in utero, we identified all cases exposed to levetiracetam. Three of 117 exposed pregnancies had an MCM (2.7%; 95% CI 0.9% to 7.7%); all 3 were exposed to other AEDs.

Noninvasive discrimination of rejection in cardiac allograft recipients using gene expression profiling

Rejection diagnosis by endomyocardial biopsy (EMB) is invasive, expensive and variable. We investigated gene expression profiling of peripheral blood mononuclear cells (PBMC) to discriminate ISHLT grade 0 rejection (quiescence) from moderate/severe rejection (ISHLT > or = 3A). Patients were followed prospectively with blood sampling at post-transplant visits. Biopsies were graded by ISHLT criteria locally and by three independent pathologists blinded to clinical data. Known alloimmune pathways and leukocyte microarrays identified 252 candidate genes for which real-time PCR assays were developed. An 11 gene real-time PCR test was derived from a training set (n = 145 samples, 107 patients) using linear discriminant analysis (LDA), converted into a score (0-40), and validated prospectively in an independent set (n = 63 samples, 63 patients). The test distinguished biopsy-defined moderate/severe rejection from quiescence (p = 0.0018) in the validation set, and had agreement of 84% (95% CI 66% C94%) with grade ISHLT > or = 3A rejection. Patients >1 year post-transplant with scores below 30 (approximately 68% of the study population) are very unlikely to have grade > or = 3A rejection (NPV = 99.6%). Gene expression testing can detect absence of moderate/severe rejection, thus avoiding biopsy in certain clinical settings. Additional clinical experience is needed to establish the role of molecular testing for clinical event prediction and immunosuppression management.

Common VKORC1 and GGCX polymorphisms associated with warfarin dose

We report a novel combination of factors that explains almost 60% of variable response to warfarin. Warfarin is a widely used anticoagulant, which acts through interference with vitamin K epoxide reductase that is encoded by VKORC1. In the next step of the vitamin K cycle, gamma-glutamyl carboxylase encoded by GGCX uses reduced vitamin K to activate clotting factors. We genotyped 201 warfarin-treated patients for common polymorphisms in VKORC1 and GGCX. All the five VKORC1 single-nucleotide polymorphisms covary significantly with warfarin dose, and explain 29-30% of variance in dose. Thus, VKORC1 has a larger impact than cytochrome P450 2C9, which explains 12% of variance in dose. In addition, one GGCX SNP showed a small but significant effect on warfarin dose. Incorrect dosage, especially during the initial phase of treatment, carries a high risk of either severe bleeding or failure to prevent thromboembolism. Genotype-based dose predictions may in future enable personalised drug treatment from the start of warfarin therapy.

Reversible thioridazine-induced magnetic resonance imaging-documented pituitary enlargement associated with hyperprolactinemia

OBJECTIVE

To document a case of reversible thioridazine-induced pituitary enlargement associated with hyperprolactinemia in a patient with schizophrenia.

METHODS

We describe a 19-year-old woman with paranoid schizophrenia who was taking thioridazine (a phenothiazine), in whom hyperprolactinemia, galactorrhea, oligomenorrhea, and a reversible anatomic pituitary abnormality developed. Serial magnetic resonance imaging (MRI) studies were used to assess the status of the pituitary gland during various pharmaceutical therapies.

RESULTS

Laboratory evaluation revealed increased serum prolactin (PRL) levels that ranged from 76 to 135 mg/L. Results of thyroid function tests were normal, and gonadotropins and estradiol levels were low, consistent with hyperprolactinemia. MRI revealed asymmetric enlargement of the right side of the pituitary gland. Discontinuing the thioridazine therapy resulted in normalization of the serum PRL and resolution of the pituitary abnormality. Subsequent worsening of the patient's psychiatric condition necessitated a course of electroconvulsive therapy and initiation of treatment with clozapine, a D4 dopamine receptor antagonist. At 1-year follow-up, at which time the patient was maintained on clozapine and was not taking thioridazine, both serum PRL levels and MRI findings remained normal.

CONCLUSION

Our patient was shown to have asymmetric pituitary enlargement associated with thioridazine-induced hyperprolactinemia, which reversed when use of the drug was discontinued. In patients with serum PRL levels in excess of 100 mg/L during antipsychotic drug therapy, evaluation for a prolactinoma is warranted.

How physically active are South Asians in the United Kingdom? A literature review

BACKGROUND

Moderate physical activity is protective against coronary heart disease (CHD) and diabetes, both important public health problems among UK South Asian (Indian, Pakistani and Bangladeshi) ethnic groups. We assessed the evidence that physical activity is lower in South Asian groups than in the general population.

METHODS

We carried out a systematic literature review of studies describing levels of physical activity and fitness in UK South Asians using MEDLINE, EMBASE, the Cochrane databases, hand searching of relevant journals and review of reference lists.

RESULTS

We identified 12 studies in adults and five in children. Various methods were used to assess physical activity and fitness, but all the studies reported lower levels among South Asian groups. The differences were substantial, particularly among women and older people. For example, the Health Survey for England found that Indian, Pakistani and Bangladeshi men were 14, 30 and 45 per cent less likely than the general population to meet current guidelines for physical activity. Limited information was provided about translation and adaptation of questionnaires.

CONCLUSION

Levels of physical activity were lower in all South Asian groups than the general population and patterns of activity differed. No studies used validated measures. Insufficient attention has been paid to issues of cross-cultural equivalence. With these caveats, low levels of physical activity among UK South Asian ethnic groups may contribute to their increased risk of diabetes and CHD. Closer attention to validity, translation and adaptation is necessary to monitor changes and assess the effectiveness of interventions to increase physical activity.