Preoperative embolization of hypervascular head and neck tumours

The embolization of vascular tumours of the head and neck has become an important adjunct to the surgical treatment of these tumours. A vascular tumour in the head and neck region in a surgically treatable patient may be a candidate for embolization. Palliative embolization may be the sole treatment for high risk patients. Reducing intraoperative bleeding may shorten surgery time thus decreasing morbidity and mortality. The purpose of this study is to assess the efficacy of embolization as an adjunct to surgery or as a curative measure in the management of hypervascular head and neck tumours. We retrospectively reviewed the records of 46 consecutive patients (27 men and 16 women; mean age, 37.8 years) with 48 hypervascular head and neck tumours that had undergone preoperative transarterial, direct puncture or combined mode of embolization. Diagnosis of tumours was made on the basis of findings of imaging studies. The 46 patients underwent embolization either through transarterial route, by direct puncture technique or both direct puncture and arterial route. The devascularization reached 90–95% with the use of NBCA. The amount of devascularization reached by transarterial particle embolization is a little lesser. One patient (carotid body tumour) developed mild unilateral seventh, ninth and 10th cranial nerve palsy after transarterial embolization, transient hemiparesis was seen in another patient (nasopharyngeal angiofibroma). Both patients improved completely with steroids and had no deficit on follow up. One patient developed delayed glue migration into the middle cerebral artery territory 6 h after the procedure with no reported increase in size of the lesion in the following 5 years. Preoperative embolization of hypervascular tumour of head and neck region appears to be safe and improves the chance of complete removal during surgery with minimal blood loss.     

European concerted action on anticoagulation. Use of plasma samples to derive international sensitivity index for whole-blood prothrombin time monitors.

BACKGROUND: To simplify International Sensitivity Index (ISI) calibration, the possibility of substituting fresh plasma for fresh whole-blood samples with point-of-care testing (POCT) whole-blood monitors was investigated in a three-center study of three different POCT systems. METHODS: A modified full WHO calibration procedure based on 20 healthy controls and 60 coumarin-treated patients was performed on three monitoring systems with whole-blood and plasma samples against plasma tested using the European Concerted Action on Anticoagulation (ECAA) rabbit reference plain thromboplastin and the manual prothrombin time (PT) method. RESULTS: With one of the three systems, the mean ISI was 1.51 for whole blood and 1.49 for plasma; with the second system, the mean ISI was 1.08 for both whole blood and plasma. With the third system, however, the difference between the mean ISI for whole blood and that for plasma was greater (1.15 and 1.01, respectively). Overall, the precision of the calibrations was less than with traditional manual plasma PT testing. CONCLUSIONS: Provided that an appropriate calcium chloride concentration is used, the plasma PT results can be used for accurate ISI calibration of two of these three whole-blood POCT systems. Precision criteria need to be modified for POCT monitors.     

Shigatoxin triggers thrombotic thrombocytopenic purpura in genetically susceptible ADAMTS13-deficient mice

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening illness caused by deficiency of the vWF-cleaving protease ADAMTS13. Here we show that ADAMTS13-deficient mice are viable and exhibit normal survival, although vWF-mediated platelet-endothelial interactions are significantly prolonged. Introduction of the genetic background CASA/Rk (a mouse strain with elevated plasma vWF) resulted in the appearance of spontaneous thrombocytopenia in a subset of ADAMTS13-deficient mice and significantly decreased survival. Challenge of these mice with shigatoxin (derived from bacterial pathogens associated with the related human disease hemolytic uremic syndrome) resulted in a striking syndrome closely resembling human TTP. Surprisingly, no correlation was observed between plasma vWF level and severity of TTP, implying the existence of TTP-modifying genes distinct from vWF. These data suggest that microbe-derived toxins (or possibly other sources of endothelial injury), together with additional genetic susceptibility factors, are required to trigger TTP in the setting of ADAMTS13 deficiency.     

Timing of prophylactic antibiotic administration in the uninfected laboring gravida: a randomized clinical trial

OBJECTIVE: The purpose of this prospective study was to determine whether the timing of prophylactic antibiotics at cesarean delivery influences maternal/neonatal infectious morbidity. STUDY DESIGN: In this double-blind placebo-controlled trial, cefazolin was given at skin incision (group A) or at cord clamping (group B). Patients were eligible for the trial if they had labored and required a cesarean delivery. RESULTS: Over a 30-month period 303 patients with singleton pregnancies entered the trial; 153-group A, 149-group B. Demographics, indication for cesarean delivery (P = .54), and operative time (P = .999), as well as rates of endometritis (RR 0.67, 95% CI 0.42-1.07), wound infection (RR 0.84, 95% CI 0.45-1.55), neonatal sepis (RR 1.28, 95% CI 0.91-1.79), and NICU admissions (RR 1.28, 95% CI 0.91-1.79) were similar between the 2 groups. CONCLUSION: There was no difference in maternal infectious morbidity whether antibiotics were given before skin incision or at cord clamping.     

Isolation and characterization of type I signal peptidase of different malaria parasites

Type I signal peptidases are important membrane-bound serineproteases responsible for the cleavage of the signal peptide ofthe proteins. These enzymes are unique serine proteases thatcarry out catalysis using a serine/lysine catalytic dyad. In thepresent study, we report the isolation of type I signal peptidasefrom the malaria parasites Plasmodium falciparum,Plasmodium knowlesi, and Plasmodium yoelii andsome characterization of type I signal peptidase ofPlasmodium falciparum. We show that these enzymes arehomologous to signal peptidases from various sources and alsocontain the conserved boxes present in other type I signalpeptidases. The type I signal peptidase from P falciparumis an intron-less and a single-copy gene. The results also showthat the enzyme from Plasmodium falciparum is subject toself-cleavage and it has been demonstrated to possess type Isignal peptidase activity in E coli preprotein processingin vivo by complementation assay. This study will be helpful inunderstanding one of the important metabolic pathways “thesecretory pathway” in the parasite and should make an importantcontribution in understanding the complex process of proteintargeting in the parasite.     

Performance improvement of the SPIHT coder based on statistics of medical ultrasound images in the wavelet domain

This paper proposes some modifications to the state-of-the-art Set Partitioning In Hierarchical Trees (SPIHT) image coder based on statistical analysis of the wavelet coefficients across various subbands and scales, in a medical ultrasound (US) image. The original SPIHT algorithm codes all the subbands with same precision irrespective of their significance, whereas the modified algorithm processes significant subbands with more precision and ignores the least significant subbands. The statistical analysis shows that most of the image energy in ultrasound images lies in the coefficients of vertical detail subbands while diagonal subbands contribute negligibly towards total image energy. Based on these statistical observations, this work presents a new modified SPIHT algorithm, which codes the vertical subbands with more precision while neglecting the diagonal subbands. This modification speeds up the coding/decoding process as well as improving the quality of the reconstructed medical image at low bit rates. The experimental results show that the proposed method outperforms the original SPIHT on average by 1.4 dB at the matching bit rates when tested on a series of medical ultrasound images. Further, the proposed algorithm needs 33% less memory as compared to the original SPIHT algorithm.     

Multiple high-intensity focused ultrasound probes for kidney-tissue ablation

BACKGROUND AND PURPOSE: To investigate kidney-tissue ablation by high-intensity focused ultrasound (HIFU) using multiple and single probes. MATERIALS AND METHODS: Ultrasound beams (1.75 MHz) produced by a piezoceramic element (focal distance 80 mm) were focused at the center of renal parenchyma. One of the three probes (mounted on a jig) could also be used for comparison with a single probe at comparable power ratings. Lesion dimensions were examined in perfused and unperfused ex vivo porcine kidneys at different power levels (40, 60, and 80 W) and treatment times (4, 6, and 8 seconds). RESULTS: At identical power levels, the lesions induced by multiple probes were larger than those induced by a single probe. Lesion size increased with increasing pulse duration and generator power. The sizes and shapes of the lesions were predictably repeatable in all samples. Lesions in perfused kidneys were smaller than those in unperfused kidneys. CONCLUSIONS: Ex vivo, kidney-tissue ablation by means of multiple HIFU probes offers significant advantages over single HIFU probes in respect of lesion size and formation. These advantages need to be confirmed by tests in vivo at higher energy levels.     

Giant ossifying chondroma of skull

We report a rare case of giant ossifying chondroma of skull arising from temporoparietal region in a 14-year-old female, which was successfully excised. While reviewing world literature few cases of extracranial chondromas arising from the skull base were found.