Does an intraoperative finding of an intact dural sac help to prognosticate neurological recovery in cauda equinal and epiconal injuries in thoracolumbar fractures? An analysis of 31 patients

Objective

To evaluate the effect of integrity of dural sac in determining motor neurological recovery in patients with cauda equinal and epiconal injuries in vertebral fractures at thoracolumbar junction.

Methods

Thirty-one patients with single-level vertebra fracture over T12–L2 with cauda equinal or epiconal injuries that underwent posterior spinal decompression and stabilization were evaluated in the period between 2006 and 2012. All patients included had motor incomplete ASIA C in neurology and were either Type B or C (AO/Magerl classification) of fracture morphology. Radiologist opinion to confirm the level of conus in MRI was done preoperatively. Intraoperative findings with respect to intactness of dura was noted. All MRI images were postoperatively evaluated by an independent, blinded radiologist for evidence of dural breach caused by the trauma. All participants provided basic demographic data, ambulatory status, and current neurology and received neurologic examination at intervals. The differences in neurologic injury sites and functional walkers in patients with different levels of vertebral injury were analyzed. Receiver operating characteristic curve analysis was used to define the cut-off value of lower extremities motor score (LEMS) in functional walkers and non-walkers. All patients were seen at a postoperative follow-up of minimum 18 months.

Results

Data of the 31 patients were analyzed. Seventeen patients (55 %) had epiconus and lumbar roots lesions and 14 (45 %) had cauda equina lesions. The injury was at the T12 vertebra in 9 patients (29 %), L1 in 12 (39 %) and in L2 in 10 patients (32 %). Mean LEMS for patients with T12, L1, and L2 fractures were calculated. Fourteen patients had intraoperative findings of intact dura as against 17 patients with dural breach. MRI images when revisited by an independent radiologist by keeping him blind about the intraoperative surgeons findings showed statistically very good interobserver agreement (κ = 0.618) with regard to integrity of the dural sac. Postoperative neurological assessment at minimum 18 months follow-up showed that four out of the 14 patients with intact dura were walkers (28 %) whereas of the 17 patients with dural breach, 13 were walkers (82 %).

Conclusion

Neurological recovery in cauda equinal and epiconal injuries in thoracolumbar fractures is significantly less likely in an intact dural sac, probably because the dural breach prevents the roots to take as much impact as compared to an intact dural sac.

     

Improvement in CD 4 counts in HIV positive patients treated with HAART and antitubercular drugs: an observational study from North India

A decrease in CD4 counts in HIV positive patients with concomitant tuberculosis leads to an increase in the morbidity and mortality. Little data exists about the use of antiretroviral drugs along with antitubercular drugs on the improvement in CD4 counts from this part of country. The records of 119 HIV and TB positive patients were obtained from immunodeficiency clinic of tertiary care centre of North India who were on drug treatment for both the diseases and were analysed for demographic profile and effects on CD4 counts. There was a statistically significant improvement in the CD4 counts of the patients as compared to their baseline values mean (SD) as 120.03 (124.1) at visit one to 270.2 (141.3) at visit two (p < 0.01) and 320.9 (184.3) at visit three (p < 0.05). Six patients died during the period of evaluation. Concomitant use of antitubercular drugs with antiretroviral drugs has resulted in a significant improvement in the CD4 counts which is a marker of delay in disease progression.     

Predicting negligence in female sterilization failure using time interval to sterilization failure: analysis of 131 cases

BACKGROUND: Sterilization failure due to 'tubal non-occlusion' or 'wrong structure sterilization' is considered negligent, whereas 'spontaneous tubal recanalization' or 'fistula formation' is considered non-negligent. We examined whether interval to pregnancy failure was predictive of a negligent rather non-negligent failure mechanism. We aim to test this hypothesis in a selected population series of known mechanisms of sterilization failure and their time interval to failure. METHODS: Analyses of 131 failed sterilizations pooled from UK (NHS Litigation Authority, Medical Protection Society and our hospital), Australia and a qualitative systematic review. RESULTS: We identified 88 negligent and 43 non-negligent sterilization failures. Filshie and ring methods failed earlier than diathermy and Pomeroy methods. Sterilization failure occurred significantly earlier in negligent than non-negligent failure mechanisms [median failure intervals 7.0 versus 12.0 months; Hazard ratio (2.35 95% CI 1.31-4.21)]. Knowing that sterilization failure occurred early, increased the probability that the failure mechanism was likely to be negligent rather than non-negligent. CONCLUSIONS: A short interval to failure is suggestive of a negligent failure mechanism. There is less certainty in the predictive value of longer time intervals on the mechanism of failure due to a paucity of cases. A national register of failed sterilizations that have been systematically investigated is needed to improve our understanding of negligent and non-negligent failure mechanisms.     

Mechanism-Based Pharmacokinetic Modeling to Evaluate Transporter-Enzyme Interplay in Drug Interactions and Pharmacogenetics of Glyburide

The purpose of this study is to characterize the involvement of hepato-biliary transport and cytochrome-P450 (CYP)-mediated metabolism in the disposition of glyburide and predict its pharmacokinetic variability due to drug interactions and genetic variations. Comprehensive in vitro studies suggested that glyburide is a highly permeable drug with substrate affinity to multiple efflux pumps and to organic anion transporting polypeptide (OATP)1B1 and OATP2B1. Active hepatic uptake was found to be significantly higher than the passive uptake clearance (15.8 versus 5.3 μL/min/10⁶-hepatocytes), using the sandwich-cultured hepatocyte model. In vitro, glyburide is metabolized (intrinsic clearance, 52.9 μL/min/mg-microsomal protein) by CYP3A4, CYP2C9, and CYP2C8 with fraction metabolism of 0.53, 0.36, and 0.11, respectively. Using these in vitro data, physiologically based pharmacokinetic models, assuming rapid-equilibrium between blood and liver compartments or permeability-limited hepatic disposition, were built to describe pharmacokinetics and evaluate drug interactions. Permeability-limited model successfully predicted glyburide interactions with rifampicin and other perpetrator drugs. Conversely, model assuming rapid-equilibrium mispredicted glyburide interactions, overall, suggesting hepatic uptake as the primary rate-determining process in the systemic clearance of glyburide. Further modeling and simulations indicated that the impairment of CYP2C9 function has a minimal effect on the systemic exposure, implying discrepancy in the contribution of CYP2C9 to glyburide clearance.     

Light-induced damage to ocular lens cation pump: prevention by vitamin C.

The cation pump activity of the ocular lens was damaged by exposure to light in the presence of riboflavin phosphate. The intensity of light was similar to that used for reading purposes. The observed light-induced damage was due to superoxide or its derivatives, the superoxide being produced photochemically. Such damage was attenuated by vitamin C in amounts comparable to that in the aqueous humor. Thus, a new role for the high ascorbate level present in the anterior chamber fluid and the lens has been suggested. Ascorbate in other tissues also might have this novel physiological function of protecting against damage due to superoxide and its derivatives produced during normal cellular oxidation.     

TB, HIV-associated TB and multidrug-resistant TB on Thailand's border with Myanmar, 2006-2007

Objective To measure the burden and improve management of tuberculosis (TB), HIV‐associated TB and MDR TB in Tak Province, Thailand, which borders Myanmar. Methods From September 2006 to August 2007, we collected uniform data about TB cases and enhanced human immunodeficiency virus (HIV) counselling and testing. We provided mycobacterial culture and drug‐susceptibility testing in public or non‐governmental organization facilities. Patients were classified by nationality and, for non‐Thais, by migration status. Results Of 1662 TB cases in the 12‐month period, 1087 (65%) occurred in non‐Thais. Of non‐Thais, 415 (38%) lived in Myanmar but crossed the border for healthcare. HIV infection was diagnosed in 18% of Thais compared with 12% of non‐Thais (P < 0.01); HIV status was unknown for 22% of Thais and 27% of non‐Thais (P = 0.02). Overall, multidrug‐resistant (MDR) TB was diagnosed in 27 patients, 19 (70%) in non‐Thais. Among TB cases never previously treated for TB, no MDR cases were diagnosed in Thais or in Myanmar refugees, but six cases were diagnosed in migrants from Myanmar. Conclusions In Thailand, TB, HIV‐associated TB and MDR TB in migrants from Myanmar are important public health problems; they need to be resolved in both the countries.     

Down-regulation of myometrial atrial natriuretic factor receptors by progesterone and pregnancy and up-regulation by oestrogen in rats.

We previously reported that pregnancy and progesterone treatment abolish and ovariectomy reduces the tocolytic activity of atrial natriuretic factor (ANF) on rat uterus. The present study was carried out to determine whether the hormonal state of the animal influences myometrial ANF receptors. A single high-affinity binding site for 125I-labelled ANF(1-28) was detected in myometrial membrane preparations partially purified by discontinuous sucrose gradient centrifugation. The specifically bound ANF could be displaced completely by unlabelled ANF(1-28) (biologically active circulating form of ANF), partially (approximately 50%) by the clearance receptor (ANF-R2) ligand, ANF(4-23), and insignificantly by angiotensin II, vasopressin, carbachol and progesterone. Maximum binding capacities (fmol/mg protein +/- S.E.M.) of myometrial membrane preparations for ANF were as follows: vehicle-treated cyclic rats, 30.2 +/- 5.9 (n = 6); oestrogen-treated virgin rats, 55.8 +/- 7.1 (n = 8); progesterone-treated virgin rats, 21.9 +/- 2.4 (n = 6); 20-day pregnant rats, 18.9 +/- 4.3 (n = 4); ovariectomized rats, undetectable (n = 3); ovariectomized rats treated with oestrogen, 50.2 +/- 4.1 (n = 3); virgin rats treated with progesterone antagonist RU 486, 64.5 +/- 5.2 (n = 3). Relative to cyclic rats, oestrogen and RU 486 caused a significant (P less than 0.05) increase and progesterone and pregnancy caused a significant (P less than 0.05) decrease in ANF myometrial receptors. The hormonal state did not change dissociation constants for ANF binding to myometrial preparations.(ABSTRACT TRUNCATED AT 250 WORDS)