Expression of green fluorescent protein in insect larvae and its application for heterologous protein production

Many eukaryotic proteins have been successfully expressed in insect cells infected with a recombinant baculovirus derived from the Autographa californica nuclear polyhedrosis virus (AcNPV). There are, however, disadvantages with this cell-based system when carried out in suspension cultures at high bioreactor volume (e.g., limited oxygen transfer, susceptibility to contamination, high cost). These problems can be avoided by using whole larvae as the "reactors." There are, however, other problems encountered with larvae, one being their inaccessibility for product sampling. To combat this problem, we have investigated the expression of green fluorescent protein (GFP) as a reporter molecule in Trichoplusia ni insect larvae. A high production level of GFPuv (1.58 mg per larva, 26% of total protein) was obtained, enabling the rapid and non-invasive monitoring of GFP. Bright green light was emitted directly from the large opaque carcasses ( approximately 30mm) after illumination with UV light. Based on the green light intensity and a correlation between intensity and GFP mass, we determined the optimal harvest time (c.a. approximately 3 days post-infection). In parallel experiments, we expressed human interleukin-2 (IL-2) from another recombinant baculovirus with an almost identical expression profile. Since both GFP and IL-2 were rapidly degraded by protease activity during the fourth day post-infection (another disadvantage with larvae), we found an accurate determination of harvest time was critical. Correspondingly, our results demonstrated that GFP was an effective on-line marker for expression of heterologous protein in insect larvae.

Predictors of compliance with a mass drug administration programme for lymphatic filariasis in Orissa State, India 2008

OBJECTIVES

To assess the performance of an educational campaign to increase adherence to a mass-administered DEC regimen against lymphatic filariasis (LF) in Orissa, and to identify factors that could enhance future campaigns.

METHOD

Randomized cluster survey, comparing areas that did and did not receive the educational campaign, using a household coverage survey and knowledge, attitudes and practices (KAP) survey.

RESULTS

LF MDA coverage for the entire population (n = 3449) was 56% (95% CI: 50.0-61.9). There was no statistical difference between the areas that did and did not receive the educational campaign. The most common barriers to adherence were fear of medication side effects (47.4%) and lack of recognition of one's risk for LF (15.8%). Modifiable, statistically significant, multivariable predictors of adherence were knowing that DEC prevents LF (aOR = 2.6, 95% CI: 1.4-5.1), knowing that mosquitoes transmit LF (aOR = 1.9, 95% CI: 1.1-3.2), and knowing both about the mass drug administration (MDA) in advance and that mosquitoes transmit LF (aOR = 5.4, 95% CI: 2.8-10.4).

CONCLUSIONS

India needs to increase compliance with MDA programmes to reach its goal of interrupting LF transmission. Promoting a simple public health message before MDA distribution, which takes into account barriers to and predictors of adherence, could raise compliance with the LF MDA programme.

Public health and economic costs of investigating a suspected outbreak of Legionnaires' disease

This paper provides one of the first assessments of the burden of both the public health investigation and the economic costs associated with an apparent outbreak of Legionnaires' disease (LD) in South East London. In addition to epidemiological, microbiological and environmental investigations, we collected data on the staff time and resources committed by the 11 main organizations responsible for managing the outbreak. Of the overall estimated costs of 455,856 pounds, only 14% (64,264 pounds) was spent on investigation and control of the outbreak compared with 86% (391,592 pounds) spent on the hospital treatment of the patients. The time and money spent on public health services in this investigation appear to represent good value for money considering the potential costs of a major outbreak, including the high case-fatality rate in LD generally and the high health-care costs. Further research is needed to determine optimum strategies for the cost-effective use of health system resources in investigations of LD. Whether the threshold for investigation of cases should be based on observed incidence rates or the cost-effectiveness of investigations, or both, should be debated further.

The impact of intra-operative high field magnetic resonance imaging on clinical decision making during oncologic neurosurgical procedures

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Background: Existing image guided surgical (IGS) technology used during resection of brain tumors is based on preoperative imaging modalities and are limited by their inability to demonstrate extent of resection (EOR) and compensate for anatomical changes which occur as a result of surgical manipulation (e.g. brain shift, tumor resection, spinal fluid loss). Having the ability to perform MRI during brain tumor surgery obviates many of these limitations. The purpose of this study was to determine the impact of intra-operative imaging with a high field MRI on brain tumor resection. Methods: Since September 2006, a total of 23 patients with brain tumors underwent resection at The University of Texas M. D. Anderson Cancer Center with intra-operative MR guidance (BrainLAB IGS system integrated with a 1.5T Siemens Espree scanner). For each patient, appropriate imaging was performed prior to craniotomy. Resection was then performed using image guidance. Surgeons completed a questionnaire documenting the reason for the scan and provided an estimation of EOR prior to and after the intraoperative scan. Multiple intraoperative scans were performed at the discretion of the operating surgeon. Results: In 23 patients, 25 scans were performed. The patients had a diagnosis of glioma (21), lymphoma (1), and schwannoma (1). Reasons for performing a scan included: evaluate EOR in 23 (92%) or update the IGS system in 2 (8%). Surgeons indicated in 21/23 (91%) scans performed to evaluate the extent of resection that they would have terminated the surgery prior to the scan. In 9/21 cases (43%), further surgery was performed after the scan to maximize EOR. In 10/24 (42%) cases, the pre-scan estimate of residual tumor matched the post-scan amount. The amount of residual tumor was correctly assessed (within 10%) prior to review of the MRI in 19/24 cases. The correlation between the pre-scan estimation of residual tumor and actual post-scan tumor was high (correlation coefficient 0.81, p<0.05). Conclusions: High field intra- operative MRI with high spatial resolution is a useful adjunct to a neurosurgical oncology practice and alters surgical decision making in a significant number of cases.

[Table: see text]

4 years' experience of head and neck tuberculosis in a south London hospital

In a south London department of otorhinolaryngology and head and neck surgery, 33 cases of tuberculosis were diagnosed in 4 years. The most common presentation was cervical adenitis (58%) and in some cases the initial investigations suggested malignant disease. Most of the patients were of non-British origin but none proved to be HIV seropositive. Fine-needle aspiration was positive for tuberculosis in 7 of 19 patients. 21 patients required a surgical procedure for diagnosis.

4 Years’ Experience of Head and Neck Tuberculosis in a South London Hospital

In a south London department of otorhinolaryngology and head and neck surgery, 33 cases of tuberculosis were diagnosed in 4 years. The most common presentation was cervical adenitis (58%) and in some cases the initial investigations suggested malignant disease. Most of the patients were of non-British origin but none proved to be HIV seropositive. Fine-needle aspiration was positive for tuberculosis in 7 of 19 patients. 21 patients required a surgical procedure for diagnosis.

Platelet storage solution improves the in vitro function of preserved platelet concentrate

BACKGROUND AND OBJECTIVES

Stored platelets develop biochemical lesions, manifest as depressed haemostatic function, clot retraction and wound healing. ViaCyte trade mark, a proprietary experimental preservative solution (comprising D-ribose, D-glucose, Hanks solution, Hepes solution, bovine serum albumin, tic anticoagulant peptide and sterile water), was tested in comparison with the presently accepted storage solution, citrate-dextrose-phosphate-plasma (CDP-P), to evaluate its ability to preserve platelet function during storage.

MATERIALS AND METHODS

Platelets stored in ViaCyte and platelets suspended in CDP-P were transferred to polypropylene tubes with PL732 covers and analysed for adenine nucleotide levels (ATP molecules), in vitro agonist-mediated P-selectin expression and aggregation.

RESULTS

After 5 days of storage at room temperature, 12.2% of platelets stored in ViaCyte exhibited P-selectin expression at rest, and 64.2% exhibited P-selectin expression upon activation with thrombin challenge, an increase of 52%. Platelets stored in CDP-P exhibited 44.4% P-selectin expression at rest, suggesting significant activation during storage, and thrombin stimulation resulted in P-selectin expression of 47.9%, an increase of only 2.5% (P< or =0.002, untreated vs. treated). ViaCyte also maintained ATP levels throughout the storage period, while these levels became depressed in platelets stored in CDP-P (P< or =0.02, untreated vs. treated). Storing platelets in the experimental preservative solution maintained their ability to aggregate, while control platelets lost their ability to aggregate in response to agonist.

CONCLUSIONS

ViaCyte appears to protect platelets during storage, reflected by a low level of induced lesions. Platelets stored in ViaCyte maintain energy levels at their resting state, which preserves their ability to aggregate and secrete granule contents, and ensures the availability of additional platelets for activation upon in vitro challenge.

[Preliminary experience with balloon kyphoplasty for the treatment of painful osteoporotic compression fractures]

PURPOSE

To describe the technique and to evaluate the safety and efficacy of percutaneous kyphoplasty as a new treatment in patients with painful osteoporotic vertebral body compression fractures of the lumbar and thoracic spine.

MATERIALS AND METHODS

In this prospective study balloon kyphoplasty was performed in 34 consecutive patients (25 females, 9 males; mean age 75 years) with 56 painful osteoporotic vertebral fractures (from T6-L5), of which 22 showed a posterior wall involvement and retropulsion on preoperative CT. The median duration of symptoms was 9.7 weeks. Symptomatic levels were identified by correlating the clinical presentation with MRI, conventional radiographs and CT including bone-densitometry. Pre- and postoperative examinations (radiographs, CT) as well as Karnofsky and visual analogy pain scores (Visual Analog Scale = VAS) were documented and compared to evaluate the success of the procedure.

RESULTS

The median Karnofsky score improved from 40 % (pre-) to 70 % (post-treatment). Simultaneously, median pain scores (VAS) decreased from 64 (pre-) to 21 (post-treatment) (p < 0.001). Perioperative morbidity included one transient L2 nerve root bruise. The procedure led to a partial restoration of the height of the vertebral body by reducing the median sagittal index from 11.5(3) to 5(3). In none of our patients, the procedure led to worsening of the fracture-induced narrowing of the spinal canal. Clinically asymptomatic cement leakage occurred in 10 cases, with leakage 4 times into the paraspinal space, 3 times into the spinal canal and 3 times into the disc space.

CONCLUSION

Balloon kyphoplasty is a safe and effective procedure. It is applicable even in fractures with posterior wall involvement since it is a low-pressure technique in contrast to vertebroplasty and restores vertebral body height partially. It results in immediate clinical improvement of mobility and pain relief. While short-term results are excellent, follow-up data have to be awaited for the final judgment of this method.

Biotechnological applications of green fluorescent protein

Since its first use as a reporter gene in 1994, green fluorescent protein (GFP) has served as the researcher's agent: slipping, virtually undetected, into unseen spaces, reporting back valuable information, and securing the delivery of precious cargo through hostile domains. GFP's strength lies in its small size, formidable stability, and relative ease of use. It requires only oxygen and an energy source to do its work, which can be supplied at low cost and high precision, respectively. With such a low threshold for use, GFP is often the first line of inquiry into an unknown space. Here is provided a brief compendium of GFP's contributions to biotechnology. They are linked by a need for a level of information that was previously inaccessible, both spatially and temporally. Protein fusions, transcriptional reporters, whole-organism visualization, and various other screening applications are reviewed with respect to biotechnological applications. Germane molecular improvements to GFP are also discussed.

Expression profiling of B cell chronic lymphocytic leukemia suggests deficient CD1-mediated immunity, polarized cytokine response, altered adhesion and increased intracellular protein transport and processing of leukemic cells

We used oligonucleotide microarrays to profile the expression of chronic lymphocytic leukemia (CLL) B cells from eight patients compared with CD5-expressing normal B cells from four donors and with pooled normal circulating B cells. Of 6790 genes examined, we identified 87 genes that were differentially expressed at least two-fold between CLL and the normal B cells. CLL cells significantly down-regulated transcripts from CD1c and CD1d genes, which encode proteins known to present lipid antigen and mediate innate and adaptive immunity. The expression pattern was also consistent with reduced signaling by interferon gamma but increased response to interleukin 4 in leukemic cells. CLL cells increased the expression of several collagen-associated extracellular matrix and adhesion molecules, up-regulated many genes involved in intracellular protein transport and processing, while downregulating genes involved in proliferation and metabolism. Based on the expression pattern, we propose that CLL-B cells prolong their survival through increased interaction with survival factors such as IL-4, and through various mechanisms of evading the immune response, such as turning off the expression of CD1c and CD1d, reducing immunogenic response to interferon gamma, inactivating T cell in B-T interaction and increasing the expression of immunoglobulin receptors which neutralize antibody-dependent cell-mediated cytotoxicity.