Gene Electrotransfer via Conductivity-Clamped Electric Field Focusing Pivots Sensori-Motor DNA Therapeutics: "A Spoonful of Sugar Helps the Medicine Go Down".

Viral vectors and lipofection-based gene therapies have dispersion-dependent transduction/transfection profiles that thwart precise targeting. The study describes the development of focused close-field gene electrotransfer (GET) technology, refining spatial control of gene expression. Integration of fluidics for precise delivery of "naked" plasmid deoxyribonucleic acid (DNA) in sucrose carrier within the focused electric field enables negative biasing of near-field conductivity ("conductivity-clamping"-CC), increasing the efficiency of plasma membrane molecular translocation. This enables titratable gene delivery with unprecedently low charge transfer. The clinic-ready bionics-derived CC-GET device achieved neurotrophin-encoding miniplasmid DNA delivery to the cochlea to promote auditory nerve regeneration; validated in deafened guinea pig and cat models, leading to improved central auditory tuning with bionics-based hearing. The performance of CC-GET is evaluated in the brain, an organ problematic for pulsed electric field-based plasmid DNA delivery, due to high required currents causing Joule-heating and damaging electroporation. Here CC-GET enables safe precision targeting of gene expression. In the guinea pig, reporter expression is enabled in physiologically critical brainstem regions, and in the striatum (globus pallidus region) delivery of a red-shifted channelrhodopsin and a genetically-encoded Ca2+ sensor, achieved photoactivated neuromodulation relevant to the treatment of Parkinson's Disease and other focal brain disorders.

Clinical utility of local over general anesthetic tonsillectomy using the BiZact™ device.

PURPOSE: Tonsillectomy under general anesthesia may be viewed preferentially to local anesthesia, due to mitigation of potential airway compromise secondary to intraoperative hemorrhage, patient discomfort and anxiety. However, this is offset by risk of increased trauma (via the endotracheal tube and gag), adverse medication reactions and cost. Here we evaluated the case for use of local anesthesia in tonsillectomy using the BiZact™ (Medtronic) device by comparing surgical outcomes and cost factors across patients where either local or general anesthesia was employed. MATERIALS AND METHODS: Retrospective cohort study of 59 BiZact™ tonsillectomy patients (38 under local anesthetic, and 21 under general anesthetic) from a single surgeon at Tauranga Hospital (public) and Grace Hospital (private) in New Zealand; March 2018 to June 2021. RESULTS: Neither patient group had any primary postoperative hemorrhage and there was comparable incidence of secondary hemorrhage (one case in each cohort). Local anesthetic tonsillectomy was well tolerated with only 2 patients requiring conversion to general anesthetic secondary to anxiety. Local anesthetic proved to be cost-effective, with a halving of hospital length of stay and significant associated overall cost saving, and did not add significantly to operating or total theatre time. Local anesthetic tonsillectomies where perioperative sedation was not required were associated with additional reductions in recovery and overall hospital stay, and cost. CONCLUSIONS: Local anesthetic BiZact™ tonsillectomy is evidently safe and cost-effective.

Audiological and Surgical Correlates of Myringoplasty Associated with Ethnography in the Bay of Plenty, New Zealand.

INTRODUCTION: This retrospective cohort study of myringoplasty performed at Tauranga Hospital, Bay of Plenty, New Zealand from 2010 to 2020 sought to identify predictive factors for successful myringoplasty with particular consideration given to the known high prevalence of middle ear conditions in New Zealand Maori. METHODS: Outcomes were surgical success (perforation closure at 1 month) and hearing improvement, which were correlated against demographic, pathological, and surgical variables. RESULTS: 174 patients underwent 221 procedures (139 in children under 18 years old), with 66.1% of patients being New Zealand Maori and 24.7% New Zealand European ethnicity. Normalized by population demographics, New Zealand Maori were 2.3 times overrepresented, whereas New Zealand Europeans were underrepresented by 0.34 times (a 6.8 times relative treatment differential). The rate of surgical success was 84.6%, independent of patient age, gender, and ethnicity. A postauricular approach and the use of temporalis fascia grafts were both correlated with optimal success rates, whereas early postoperative infection (<1 month) was correlated with ∼3 times increased failure. Myringoplasty improved hearing in 83.1% of patients (average air-bone gap reduction of 10.7 dB). New Zealand Maori patients had ∼4 times greater preoperative conductive hearing loss compared to New Zealand Europeans, but benefited the most from myringoplasty. DISCUSSION/CONCLUSION: New Zealand Maori and pediatric populations required greater access to myringoplasty, achieving good surgical and audiological outcomes. Myringoplasty is highly effective and significantly improves hearing, particularly for New Zealand Maori. Pediatric success rates were equivalent to adults, supporting timely myringoplasty to minimize morbidity from untreated perforations.

Australian Scorpion Hormurus waigiensis Venom Fractions Show Broad Bioactivity Through Modulation of Bio-Impedance and Cytosolic Calcium.

Scorpion venoms are a rich source of bioactive molecules, but characterisation of toxin peptides affecting cytosolic Ca2+, central to cell signalling and cell death, is limited. We undertook a functional screening of the venom of the Australian scorpion Hormurus waigiensis to determine the breadth of Ca2+ mobilisation. A human embryonic kidney (HEK293) cell line stably expressing the genetically encoded Ca2+ reporter GCaMP5G and the rabbit type 1 ryanodine receptor (RyR1) was developed as a biosensor. Size-exclusion Fast Protein Liquid Chromatography separated the venom into 53 fractions, constituting 12 chromatographic peaks. Liquid chromatography mass spectroscopy identified 182 distinct molecules with 3 to 63 components per peak. The molecular weights varied from 258 Da-13.6 kDa, with 53% under 1 kDa. The majority of the venom chromatographic peaks (tested as six venom pools) were found to reversibly modulate cell monolayer bioimpedance, detected using the xCELLigence platform (ACEA Biosciences). Confocal Ca2+ imaging showed 9/14 peak samples, with molecules spanning the molecular size range, increased cytosolic Ca2+ mobilization. H. waigiensis venom Ca2+ activity was correlated with changes in bio-impedance, reflecting multi-modal toxin actions on cell physiology across the venom proteome.

Does gated beam delivery impact delivery accuracy on an Elekta linac?

In this study, we evaluated the performance of an Elekta linac in the delivery of gated radiotherapy. Delivery accuracy was examined with an emphasis on the impact of using short gating windows (low monitor unit beam-on segments) or long beam hold times. The performance was assessed using a 20cm by 20cm open field with the radiation delivered using a range of beam-on and beam-off time periods. Gated delivery measurements were also performed for two SBRT plans delivered using volumetric modulated arc therapy (VMAT). Tests included both free-breathing based gating (covering a variety of gating windows) and simulated breath-hold based gating. An IBA MatriXX 2D ion chamber array was used for data collection, and the gating accuracy at low MU was evaluated using gamma passing rates. For the 20 cm by 20 cm open field, the measurements generally showed close agreement between the gated and non-gated beam deliveries. Discrepancies, however, began to appear with a 5-to-1 ratio of the beam-off to beam-on times. The discrepancies observed for these tight gating windows can be attributed to the small number of monitor units delivered during each beam-on segment. Dose distribution analysis from the delivery of the two SBRT plans showed gamma passing rates (± 1%, 2%/1 mm) in the range of 95% to 100% for gating windows of 25%, 38%, 50%, 63%, 75%, and 83%. Using a simulated sinusoidal breathing signal with a 4 second period, the gamma passing rate of free-breathing gating and breath-hold gating deliveries were measured in the range of 95.7% to 100%. In conclusion, the results demonstrate that Elekta linacs can accurately deliver respiratory gated treatments for both free-breathing and breath-hold patients. Some caution should be exercised with the use of very tight gating windows.

Scorpion toxin peptide action at the ion channel subunit level.

This review categorizes functionally validated actions of defined scorpion toxin (SCTX) neuropeptides across ion channel subclasses, highlighting key trends in this rapidly evolving field. Scorpion envenomation is a common event in many tropical and subtropical countries, with neuropharmacological actions, particularly autonomic nervous system modulation, causing significant mortality. The primary active agents within scorpion venoms are a diverse group of small neuropeptides that elicit specific potent actions across a wide range of ion channel classes. The identification and functional characterisation of these SCTX peptides has tremendous potential for development of novel pharmaceuticals that advance knowledge of ion channels and establish lead compounds for treatment of excitable tissue disorders. This review delineates the unique specificities of 320 individual SCTX peptides that collectively act on 41 ion channel subclasses. Thus the SCTX research field has significant translational implications for pathophysiology spanning neurotransmission, neurohumoral signalling, sensori-motor systems and excitation-contraction coupling. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'

Determination of Urinary Neopterin/Creatinine Ratio to Distinguish Active Tuberculosis from Latent Mycobacterium tuberculosis Infection.

Background. Biomarkers to distinguish latent from active Mycobacterium (M.) tuberculosis infection in clinical practice are lacking. The urinary neopterin/creatinine ratio can quantify the systemic interferon-gamma effect in patients with M. tuberculosis infection. Methods. In a prospective observational study, urinary neopterin levels were measured by enzyme linked immunosorbent assay in patients with active tuberculosis, in people with latent M. tuberculosis infection, and in healthy controls and the urinary neopterin/creatinine ratio was calculated. Results. We included a total of 44 patients with M. tuberculosis infection and nine controls. 12 patients had active tuberculosis (8 of them culture-confirmed). The median age was 15 years (range 4.5 to 49). Median urinary neopterin/creatinine ratio in patients with active tuberculosis was 374.1 micromol/mol (129.0 to 1072.3), in patients with latent M. tuberculosis infection it was 142.1 (28.0 to 384.1), and in controls it was 146.0 (40.3 to 200.0), with significantly higher levels in patients with active tuberculosis (p < 0.01). The receiver operating characteristics curve had an area under the curve of 0.84 (95% CI 0.70 to 0.97) (p < 0.01). Conclusions. Urinary neopterin/creatinine ratios are significantly higher in patients with active tuberculosis compared to patients with latent infection and may be a significant predictor of active tuberculosis in patients with M. tuberculosis infection.

Delivery efficiency of an Elekta linac under gated operation.

In this study, we have characterized the efficiency of an Elekta linac in the delivery of gated radiotherapy. We have explored techniques to reduce the beam-on delay and to improve the delivery efficiency, and have investigated the impact of frequent beam interruptions on the dosimetric accuracy of gated deliveries. A newly available gating interface was installed on an Elekta Synergy. Gating signals were generated using a surface mapping system in conjunction with a respiratory motion phantom. A series of gated deliveries were performed using volumetric modulated arc therapy (VMAT) treatment plans previously generated for lung cancer patients treated with stereotactic body radiotherapy. Baseline values were determined for the delivery times. The machine was then tuned in an effort to minimize beam-on delays and improve delivery efficiency. After that process was completed, the dosimetric accuracy of the gated deliveries was evaluated by comparing the measured and the planned coronal dose distributions using gamma index analyses. Comparison of the gated and the non-gated deliveries were also performed. The results demonstrated that, with the optimal machine settings, the average beam-on delay was reduced to less than 0.22 s. High dosimetric accuracy was demonstrated with gamma index passing rates no lower than 99.0% for all tests (3%/3 mm criteria). Consequently, Elekta linacs can provide a practical solution for gated VMAT treatments with high dosimetric accuracy and only a moderate increase in the overall delivery time.

Internal quality control: best practice.

There is a wide variation in laboratory practice with regard to implementation and review of internal quality control (IQC). A poor approach can lead to a spectrum of scenarios from validation of incorrect patient results to over investigation of falsely rejected analytical runs. This article will provide a practical approach for the routine clinical biochemistry laboratory to introduce an efficient quality control system that will optimise error detection and reduce the rate of false rejection. Each stage of the IQC system is considered, from selection of IQC material to selection of IQC rules, and finally the appropriate action to follow when a rejection signal has been obtained. The main objective of IQC is to ensure day-to-day consistency of an analytical process and thus help to determine whether patient results are reliable enough to be released. The required quality and assay performance varies between analytes as does the definition of a clinically significant error. Unfortunately many laboratories currently decide what is clinically significant at the troubleshooting stage. Assay-specific IQC systems will reduce the number of inappropriate sample-run rejections compared with the blanket use of one IQC rule. In practice, only three or four different IQC rules are required for the whole of the routine biochemistry repertoire as assays are assigned into groups based on performance. The tools to categorise performance and assign IQC rules based on that performance are presented. Although significant investment of time and education is required prior to implementation, laboratories have shown that such systems achieve considerable reductions in cost and labour.

Audit of internal quality control practice and processes in the south-east of England and suggested regional standards.

BACKGROUND: Internal quality control (IQC) has a long and well-established role in clinical biochemistry laboratories. However, despite the duration of use, and the publication of several articles detailing best practice, the implementation and use of IQC vary significantly between institutions. Consequently, the North Thames Audit and Quality Assurance Group undertook a region-wide audit of current IQC practice in 2006. METHODS: On aspects of IQC testing, interpretation and laboratory processes, 54 laboratories in the region were audited. RESULTS: Audit data showed significant variability in all aspects of practice, including IQC frequency, use of appropriate material, statistical processing and grades of staff involved. CONCLUSIONS: Some of the variation in practice may affect the effectiveness of laboratory IQC, and thus the adequacy of a laboratory to monitor system performance. Consequently, a set of proposed regional standards have been developed and disseminated, prior to re-audit at a future date.

Profound hypocalcaemia associated with bilateral cataracts post-total thyroidectomy.

Profound hypocalcaemia is an uncommon presentation from primary care. We describe a case of hypocalcaemia presenting 4 years after total thyroidectomy. Long-term complications of chronic hypocalcaemia are rarely seen in clinical practice today, but had occurred in this case with the development of bilateral cataracts. All patients should be monitored following thyroidectomy to ensure that hypocalcaemia does not persist. In addition to this, patients with a history of thyroid surgery presenting with cataracts should have serum calcium measured.

Gitelman's syndrome presenting as intolerance to statin therapy.

Several factors predisposing patients to statin-induced myopathy have been described. We describe a patient whose statin intolerance was associated with changes in serum potassium arising from previously undiagnosed Gitelman's syndrome.