Green pit viper antivenom from Thailand and Agkistrodon halys antivenom from China compared in treating Cryptelytrops albolabris envenomation of mice.

OBJECTIVE: To compare the relative efficacy of the green pit viper antivenom from Thailand and Agkistrodon halys antivenom from China. DESIGN. In-vivo experimental study. SETTING: A wildlife conservation organisation, a university, a poison information centre, and a regional hospital in Hong Kong. MAIN OUTCOME MEASURES: Pre- and post-antivenom lethal dose 50 (LD50) of the Cryptelytrops albolabris venom, median effective dose (ED50) of green pit viper antivenom and Agkistrodon halys antivenom against a lethal dose of the venom. SUBJECTS. Adult mice. RESULTS: The intraperitoneal LD50 of the venom from locally caught Cryptelytrops albolabris was 0.14 microL. After post-exposure treatment with 10 microL of antivenom, it was elevated to 0.36 microL and 0.52 microL by the green pit viper antivenom and the Agkistrodon halys antivenom, respectively. The ED50 was 32.02 microL for green pit viper antivenom and 6.98 microL for Agkistrodon halys antivenom. Both green pit viper antivenom and Agkistrodon halys antivenom ameliorated the lethality of Cryptelytrops albolabris venom in mice. CONCLUSION: The overall superior neutralisation capacity of Agkistrodon halys antivenom over green pit viper antivenom may be related to the geographic proximity of the venoms used for antivenom preparation. The results point towards the need for further comparison of the two antivenoms on protein or immunoglobulin weight basis, and with respect to non-lethal clinically significant toxicities.

A cross-sectional survey of snake oral bacterial flora from Hong Kong, SAR, China.

OBJECTIVE: To determine the pattern of oral bacterial flora and their sensitivity to antibiotics in freshly captured native snakes in Hong Kong SAR, People's Republic of China. METHODS: Healthy native snakes were captured and kept in a designated centre. Snake species were identified by experienced herpetologists. Mouth swabs were taken by the veterinarian using strict aseptic techniques. The snakes were released back to the wild immediately after the above procedure. Swabs were sent for microbiological studies of bacterial culture and antibiotic sensitivity. RESULTS: 47 venomous snakes of the families Colubridae, Elapidae and Viperidae and 53 non-medically important snakes were captured. 406 bacterial isolates of 72 different species were cultured: these included gram negative and positive bacterial species and also anaerobic bacterial species. With the exception of the white-lipped pit viper (Cryptelytrops albolabris), venomous snakes harboured more pathogenic bacteria and total bacteria species compared to the non-medically important species. Of the venomous snakes, the Chinese cobra (Naja atra) harboured the largest number of bacterial species. In the present study, all gram negative bacteria associated with wound infection were sensitive to levofloxacin, netilmicin and piperacillin/tazobactam. Many gram negative bacteria in the study were not sensitive to cefuroxime axetil. Amoxicillin/clavulanic acid was an appropriate choice to cover Enterococcus faecalis and anaerobes. CONCLUSION: In the presence of wound infection from snakebite injury in Hong Kong, first line empirical antibiotics include amoxicillin/clavulanic acid plus levofloxacin. Prophylactic antibiotics may be considered in selected cases of Chinese cobra (N. atra) bite, otherwise prophylactic antibiotics are not recommended in snakebite unless tissue necrosis is present.

Prevention and handling of complications of renal focal therapies.

Small renal lesions often confer relatively low oncologic risk and, as such, dictate for treatment strategies with low morbidity. Minimally invasive ablative techniques have been developed and can deliver good outcomes where used judiciously. The potential risks of treatment relate to the method of ablation, the route by which it is delivered, together with patient and tumor factors. The complications associated with radiofrequency ablation and cryoablation, delivered via percutaneous and laparoscopic approaches, are considered in this review. Percutaneous ablation appears to be associated with lower rates of morbidity but higher rates of recurrence when compared with laparoscopic ablation. The ability to dissect the lesion away from surrounding structures is limited with the percutaneous approach, which can lead to poor outcomes when treating lesions close to the ureter or hilum. Hemorrhagic complications that are seen with laparoscopic cryoablation are most often associated with tumor fracture during the freeze-thaw cycle. This is encountered most frequently in larger, peripheral lesions but may be mitigated by slowing the freeze rate. Postablation inpatient stays are often short, and early signs of complication are often nonspecific. This combination can lead to significant delay in the recognition of postablative problems with a resultant increase in morbidity. A high index of suspicion together with appropriate use of imaging allows for earlier detection and management of complications.

Minimally invasive ablative technique for the treatment of small renal masses.

Minimally invasive nephron sparing techniques are becoming popular treatment modalities in the face of smaller renal tumours diagnosed in an increasingly elderly population. Techniques include cryoablation and radiofrequency ablation, delivered via percutaneous or laparoscopic approaches. Laparoscopic cryoablation shows the lowest recurrence rates but this must be balanced against higher morbidity compared to the percutaneous approaches. To date, studies are limited by lack of biopsy data and accurate measurement of the effects of treatment on renal function. Laparoscopic partial nephrectomy represents the main minimally invasive alternative to these ablative techniques, but remains a technically challenging procedure. In the short term renal cryoablation and RFA appear to represent safe, effective minimally invasive nephron sparing techniques in the treatment of small renal tumours. Further studies examining long term recurrence rates and renal outcome will help to determine the utility of these techniques in managing renal tumours.

Does the rate of shock wave delivery affect outcomes in patients receiving shock wave lithotripsy for urinary calculi?

This Practice Point discusses a meta-analysis performed by Semins and colleagues, which included a total of 589 patients from four studies who were randomized to receive shock wave lithotripsy (SWL) delivered at either 120 shock waves per minute (fast rate) or 60 shock waves per minute (slow rate). The slow-rate group had a 10.2% increased chance of successful treatment compared with the fast-rate group (P = 0.002). Whilst this paper adds to existing evidence suggesting improved outcomes for slow-rate versus fast-rate SWL, the small sample size and heterogeneity of the studies included make it difficult to draw definitive conclusions. Varying the shock wave delivery rate according to patient, lithotripter system and stone characteristics, might form an important part of individualizing SWL treatment protocols. The potential advantages of slow-rate SWL must be weighed against the disadvantages of increased treatment times. Large multicenter studies will be required to determine how best to tailor SWL treatment to the individual patient.

The use of Raman spectroscopy to provide an estimation of the gross biochemistry associated with urological pathologies.

Near-infrared Raman spectroscopy, an optical technique that is able to interrogate biological tissues, has been used to study bladder and prostate tissues, with the objective being to provide a first approximation of gross biochemical changes associated with the process of carcinogenesis. Prostate samples for this study were obtained by taking a chip at TURP, and bladder samples from a biopsy taken at TURBT and TURP, following ethical approval. Spectra were taken from purchased biochemical constituents and different pathologies within the bladder and the prostate. We were then able to determine the biochemical basis for these pathologies by utilising an ordinary least-squares fit. We have shown for the first time that we are able to utilise Raman spectroscopy in determining the biochemical basis for the different pathologies within the bladder and prostate gland. In this way we can achieve a better understanding of disease processes such as carcinogenesis. This could have major implications in the future of the diagnosis of disease within the bladder and the prostate gland.

Raman spectroscopy for identification of epithelial cancers.

There is a real need for improvements in cancer detection. Significant problems are encountered when utilising the gold standard of excisional biopsy combined with histopathology. This can include missed lesions, perforation and high levels of inter- and intra-observer discrepancies. The clinical requirements for an objective, non-invasive real time probe for accurate and repeatable measurement of tissue pathological state are overwhelming. This study has evaluated the potential for Raman spectroscopy to achieve this goal. The technique measures the molecular specific inelastic scattering of laser light within tissue, thus enabling the analysis of biochemical changes that precede and accompany disease processes. Initial work has been carried out to optimise a commercially available Raman microspectrometer for tissue measurements; to target potential malignancies with a clinical need for diagnostic improvements (oesophagus. colon, breast, andd prostate) and to build and test spectral libraries and prediction algorithms for tissue types and pathologies. This study has followed rigorous sample collection protocols and histopathological analysis using a board of expert pathologists. Only the data from samples with full agreement of a homogeneous pathology have been used to construct a training data set of Raman spectra. Measurements of tissue specimens from the full spectrum of different pathological groups found in each tissue have been made. Diagnostic predictive models have been constructed and optimised using multivariate analysis techniques. They have been tested using cross-validation or leave-one-out and demonstrated high levels of discrimination between pathology groups (greater than 90% sensitivity and specificity for all tissues). However larger sample numbers are required for further evaluation. The discussions outline the likely work required for successful implementation of in vivo Raman detection of early malignancies.

Review of a routine test of cardiac function before aortic aneurysm surgery.

The majority of vascular surgeons employ tests of cardiac function prior to embarking on elective abdominal aortic aneurysm (AAA) repair. This study reviewed the value of measuring preoperative ventricular ejection fraction (VEF). The records of the 207 patients considered for elective AAA repair between 1994 and 2000 were reviewed. In patients who underwent surgery, morbidity and mortality data were retrieved from the vascular department database. These outcomes were correlated with the measured VEFs. In patients turned down for surgery, the reasons were determined from patients' notes, and the role that VEF played in the decision was evaluated. Low VEF did not correlate with postoperative cardiac morbidity or mortality. The range of VEF values in patients turned down for surgery was not significantly different from those who underwent AAA repair. VEF was pivotal in the decision not to operate in only one patient over the 6-year interval. This review found no evidence that routine measurement of VEF prior to elective AAA repair was valuable either in making the decision whether to operate or in predicting outcome and complications. Little or no information was added that could not be gained on simple clinical evaluation of cardiac function.