Neurotoxicity after spinal anaesthesia induced by serial intrathecal injections of magnesium sulphate An experimental study in a rat model

We have previously demonstrated in a rat model that the lumbar intrathecal injection of 0.02 ml 6.3% magnesium sulphate, a concentration iso-osmolar with rat plasma, produces a state of spinal anaesthesia and general sedation which reversed completely after 6 h, without evidence of neurotoxicity, immediately or during the week thereafter. Using the same model and five groups of six animals in each, we administered the same volume and concentration of magnesium sulphate and compared its clinical effects with those of 0.02 ml 12.6% magnesium sulphate, 0.02 ml 2% lignocaine and 0.02 ml 0.9% sodium chloride solution, given as a series of 15 injections on alternate days for a period of 1 month. The animals were then killed and their spinal cords and meninges examined histologically. No significant differences were noted in the times of onset, durations of sensory and motor blockade and the times to full recovery throughout the entire period of 1 month's observation in the animals receiving intrathecal 6.3% magnesium sulphate. In the group receiving 12.6% magnesium sulphate, the time of onset of sensory and motor blockade was shorter and the duration of both parameters was significantly longer than in the former group. Full clinical recovery and resumption of normal eating and drinking took place in both groups throughout the entire series of 15 successive intrathecal injections. Identical, mild, uniform histopathological changes in the spinal cord were seen in all the five groups, including the group in which only the intrathecal catheter was implanted. The complete recovery and benign consequences of repeated intrathecal injections of iso-osmolar magnesium sulphate in a rat model indicate a lack of neurotoxicity and provide an impetus for further trials in larger animal species, before initial clinical trials of this substance, given intrathecally, in humans.     

Persistent posttraumatic wrist pain: complex regional pain syndrome? Mycobacterium tuberculosis infection should be in the differential diagnosis

It is a common algorithm for hand surgeons to diagnose and treat persistent post-traumatic wrist pain as complex regional pain syndrome (CRPS). Although it works for many patients, some conditions that affect the wrist don’t fall in this category and worsen with this treatment practice. We present a single-handed patient who had had a non-displaced distal radius fracture and was treated as CRPS for the next three months. He was eventually diagnosed with late tuberculous tenosynovitis of the wrist and a total wrist arthrodesis was performed. We believe that Mycobacterium tuberculosis infection should be in the differential diagnosis of persistent post-traumatic joint pain. This is especially important as Mycobacterium infections are becoming more common due to an increase in patients with chronic immunosuppression and definitive diagnosis and treatment of tuberculous tenosynovitis needs a high index of clinical suspicion.     

The peri‐microvascular edema in hippocampal CA1 area in a rat model of sepsis

Encephalopathy is a common complication of sepsis. However, little is known about the morphological changes that occur in the brain during sepsis. In this study, fecal peritonitis was induced in Wistar rats, which had been monitored for 4 h before their brains were removed and samples from the CA1 area taken. In addition to higher blood pressure with a decreasing pattern and a significant drop in rectal temperature, an increased heart rate and marked respiratory failure were observed. The tissue was investigated and compared with corresponding hippocampal samples taken from sham‐operated and not operated control groups. Significantly more peri‐microvascular edema was found in the hippocampal CA1 area in the septic group. The percentages of the peri‐microvascular edema were 158.57 ± 3.6%, 122.84 ± 1.5% and 120.24 ± 1.9% in the fecal peritonitis group, sham‐operated and not operated control groups, respectively. The results may suggest that the edema observed around the microvessels may participate in the pathogenesis of the septic encephalopathy probably by causing in the microvascular permeability characteristics.     

Dosimetric evaluation of the effect of dental implants in head and neck radiotherapy.

OBJECTIVE: The aim of the study was to examine the dose enhancement from scattered radiation at bone-dental implant interfaces during simulated head and neck radiotherapy. STUDY DESIGN: Four cylindrical titanium dental implants with 3 different sizes and lengths were implanted into a human mandible in 4 different positions. Ionization measurements for 6 MV X, 25 MV X, and Co-60 gamma rays were done. Thermoluminescent dosimeter (TLD 100 ) chips were used to measure radiation dose enhancement due to the scattered electrons from titanium and electronic disequilibrium at the tissue-metal interface. RESULTS: The results showed that for Co-60, there is a 21% maximum increase in dose to alveolar mandibular bone at the close proximity to the titanium. For 6-MV x-rays the dose enhancement increase was almost the same or slightly lower than for Co-60, while for 25-MV high-energy x-rays, dose enhancement was lower than that of others. This increase in dose enhancement fell off rapidly and became insignificant at 2 mm from the interface. CONCLUSION: Total dose that may lead to osteoradionecrosis risk of the mandible is slightly but not significantly affected by the scattered dose of the dental implants of lower jaw in the radiation field exposed to 3 different radiation beams.     

The effect of a copper intra-uterine contraceptive device on the microbial ecology of the female genital tract

Bacteria isolated from 108 intra-uterine contraceptive devices (IUCD) removed from patients with pelvic inflammatory disease (PID), haemorrhage, pregnancy and from asymptomatic women, and from the genital tracts of 66 healthy controls not wearing an IUCD, were studied. No significant differences were found in the types of micro-organisms or isolation rates from IUCDs removed from women in the various clinical groups. The isolation rate of anaerobic bacteria from IUCDs removed from asymptomatic wearers was significantly lower than that from controls, with the exception of the isolation rate of actinomyces which was significantly higher in IUCD wearers and A. israelii was recovered only from IUCDs. The isolation rates of the different bacterial species varied with the duration of the device in utero. The presence of a copper IUCD altered the bacterial flora of the female genital tract. The insertion of such a device and the ecological changes that follow play a crucial role in the development of PID.     

Treg-Cell Control of a CXCL5-IL-17 Inflammatory Axis Promotes Hair-Follicle-Stem-Cell Differentiation During Skin-Barrier Repair

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Emergence of rifampicin resistance in methicillin-resistant Staphylococcus aureus isolated at a Turkish university hospital

Twenty-three rifampicin-resistant methicillin-resistant Staphylococcus aureus (MRSA) isolated in three wards at a university hospital in Turkey between June, 2000, and February, 2001, were studied for their genetic relatedness using a combination of antibiogram, coagulase serotyping, coagulase gene polymorphism (coa-RFLP), and pulsed-field gel electrophoresis (PFGE). They all expressed high-level rifampicin resistance (MIC, >256 mg/L) and were resistant to gentamicin, kanamycin, amikacin, ciprofloxacin, tetracycline, and cadmium acetate and were susceptible to fusidic acid, vancomycin, trimethoprim, and mupirocin. They belonged to the same coagulase serotype (serotype IV) and had identical coa-RFLP patterns. In contrast, PFGE generated nine banding patterns designated type A, types A1-A5, B, C, and D. The most common PFGE pattern (type A) and its subtypes (types A1-A5) were seen in 20 (87%) of the 23 isolates in the three wards. The results demonstrated the acquisition of rifampicin resistance by different MRSA clones and the spread of one clone among patients in the three wards.     

Evaluation of fractionated total body irradiation and dose rate on cataractogenesis in bone marrow transplantation

PURPOSE: To assess dose rate effect on cataractogenesis in allogeneic or autologous bone marrow transplanted patients conditioned with fractionated total-body irradiation (FTBI). MATERIALS AND METHODS: Between 1987 and 2001, a total of 105 patients have received TBI conditioning for Bone Marrow Transplantation (BMT) for hematological malignancies at Gulhane Military Medical School. 12 Gy FTBI was applied in 6 fractions over 3 consecutive days with a Co60 teletherapy machine. 46 patients who have survived and were followed up after more than one year were evaluated for cataractogenesis in relation to dose rate. Conditioning therapy included only cyclophosphamide (60 mg/kg/day for two days) + TBI with no steroid and veno-occlusive disease prophylaxis. RESULTS: The median follow-up is 32 months. Posterior subcapsular cataract developed in 5 eyes of three patients out of 46 patients. The 5-year and 10-year estimated cataract incidence in the high-dose rate (> 0.04 Gy/min) group was 29% and 43% respectively while no cataracts occurred in the low-dose rate (< or = 0.04 Gy/min) group. Cataract development in the high-dose rate group versus low-dose rate group was statistically significant (p < 0.039). CONCLUSION: Cataract is a late side effect of TBI. Low-dose rate fractionated TBI is a reliable conditioning program in BMT with effective lens sparing to avoid cataractogenesis.     

Intracellular Ca++/Mg++ homeostasis during postnatal growth of experimental rats. Multiple time-point study

In most tissues, various cell membrane ion transporting systems are not fully developed and/or maximally active at the prenatal and early postnatal stage. Their progressive development and expression are a function of growth and maturity. We performed a multiple time-point study, in order to investigate the ability of a variety of tissues to maintain appropriate Ca++ and Mg++ homeostasis at different stages of postnatal development. Total intracellular Ca++ in one-week-old rat liver, brain and spinal cord tissues was significantly elevated, compared to mature animals. It increased further through the first three weeks of gestation. Intracellular Ca++ gradually and significantly declined in adult and mature animal groups. Alterations in total intracellular Mg++ of the same tissue samples, although not so profound, paralleled changes in total intracellular Ca++. We conclude that a developmental switch in intracellular Ca++ and Mg++ homeostasis occurs one to three weeks following birth. It might be related to the incomplete development of Ca++ and Mg++ transmembrane transporting systems, previously reported as being only partially expressed at the early postnatal stage. These developmental alterations in total intracellular Ca++ and Mg++ content might serve as a regulatory mechanism, adjusting cell activities to the physiological requirements of the growing and maturing animal.