Anatomical and functional complications after tracheostomy in patients with burns and inhalation injuries

Summary It is an intricate problem to maintain a free airway in patients with smoke inhalation injuries combined with deep burns of the face, neck and chest. In this paper, we report and discuss late problems after tracheostomy seen in five patients. The causes were anatomical in three patients (tracheo-oesophageal fistula, tracheal stenosis and collapse), and functional in two (difficulties in swallowing and largyngo-spasm). The patient with a tracheo-oesophageal fistula died due to erosion of the tracheo-innominate artery. In patients with deep burns in the face, neck and chest, it is important to have a strategy of treatment to keep a free airway and to anticipate the potential development of late complications after tracheostomy.     

Optic disc oval ness,refractive error and axial length of Hong Kong Chinese

Myopic crescent, refractive error and axial length were previously investigated in Hong Kong Chinese subjects. The myopic crescent was found to correlate with axial length and myopic refraction. In this study, three groups of Hong Kong Chinese with different degrees of myopia were assessed for optic disc ovalness, refractive error and axial length. The axial length was significantly correlated with the degree of myopia, indicating that the myopia was axial in nature. The regression line shows that 0.44 mm of axial elongation would give about one dioptre of increase in myopia. The elliptical ratio of the optic disc was defined as the maximal disc diameter divided by the minimal disc diameter. All three groups showed an oval disc with vertical axis greater and an increased ovalness for the high myopic group with an elliptical ratio from 1.11 in low myopia to 1.29 in high myopia. There is a small amount (about four degrees) of temporal rotation of this vertical oval orientation, which is independent of the amount of myopia. This result shows an association between axial elongation of the globe and optic disc ovalness, in addition to the previously described temporal myopic crescent. Therefore, in myopic subjects, a vertically oval disc may be associated with a myopic refraction rather than glaucoma.     

Identification of a transferrin-binding protein from Borrelia burgdorferi.

Bacterial pathogens have evolved various strategies to acquire iron from the iron-restricted environment found in mammalian hosts. Borrelia burgdorferi should be no different with regard to its requirement for ferric iron, and previous studies have suggested that transferrin (Tf) may be a source of iron in vivo. By probing blots with Tf conjugated to horseradish peroxidase, we have identified an outer membrane protein (28 kDa) from B. burgdorferi B31 that bound holo-Tf but not apo-Tf. The 28-kDa protein bound human, rat, or mouse Tf and was produced only by low-passage (less than passage 5), virulent isolates of strain B31. In addition, the Tf-binding protein (Tbp) from strain B31 retained the ability to bind Tf after treatment with 2% sodium dodecyl sulfate-1% beta-mercaptoethanol and heating to 100 degrees C for 5 min. These properties are remarkably similar to those of the Tbp of Staphylococcus aureus and Tbp2 from Neisseria meningitidis. B. burgdorferi Sh-2-82 produced an outer membrane protein different in size, i.e., 26 kDa, but with properties similar to those of to the protein from strain B31, suggesting variation in B. burgdorferi Tbps. The exact role of the 28-kDa protein in iron acquisition by B. burgdorferi remains to be determined.     

Hepatocellular carcinoma: assessment of resectability by computed tomography and ultrasound

A retrospective review of the CT and ultrasound scans from examinations of 30 patients who had hepatocellular carcinoma (hepatoma) was undertaken with special emphasis placed on evaluation of hepatic distribution of tumor, vascular invasion, and extrahepatic spread. Although both CT and ultrasound detected hepatoma in 29 of 30 patients (96%), CT showed more extensive hepatic parenchymal involvement in eight of the patients. Vascular invasion was seen more frequently with ultrasound than with CT. Invasion into the main portal vein was seen by ultrasound in 11 of 30 patients (37%). Extrahepatic spread of tumor was much more frequently detected by CT and was present in 21 of 30 patients (70%). A reasoned approach to the diagnostic workup of hepatomas that will minimize invasive procedures and unnecessary surgery is presented.     

Arthrography of the knee: a comparative study of the accuracy of single and double contrast techniques

Single and double contrast arthrographic techniques were compared in 951 patinets with suspected meniscal injuries. Exploratory surgery of the knee was performed in 384 of these patients and good clinical follow-up was obtained in 135 patients. In the latter two groups of patients, the single contrast technique was 97% accurate in assessing the medial meniscus and 96% accurate in assessing the lateral meniscus. Double contrast arthrography was 97% accurate in assessing the medial meniscus and 93% accurate in assessing the lateral meniscus. Numerical differences in the results from the two techniques were not statistically significant. Therefore both techniques can be considered equally effective diagnostically.     

A new immobilisation method to arrange particles in a gel matrix by ultrasound standing waves

Ultrasonic forces may be used to manipulate particles in suspension. For example, a standing wave ultrasound (US) field applied to a suspension moves the particles toward areas of minimal acoustic pressure, where they are orderly retained creating a predictable heterogeneous distribution. This principle of ultrasonic retention of particles or cells has been applied in numerous biotechnological applications, such as mammalian cell filtering and red blood cell sedimentation. Here, a new US-based cell immobilisation technique is described that allows manipulation and positioning of cells/particles within various nontoxic gel matrices before polymerisation. Specifically, gel immobilisation was used to directly demonstrate that the viability of yeast cells arranged by an US standing wave is maintained up to 4 days after treatment. The versatility of this immobilisation method was validated using a wide range of acoustic devices. Finally, the potential biotechnological advantages of this US-controlled particle positioning method combined with gel immobilisation/encapsulation technology are discussed.     

Evidence of a conjugal erythromycin resistance element in the Lyme disease spirochete Borrelia burgdorferi

We report the identification of isolates of Borrelia burgdorferi strain B31 that exhibit an unusual macrolide–lincosamide (ML) or macrolide–lincosamide–streptogramin A (MLS_A) antibiotic resistance pattern. Low-passage isolates were resistant to high levels (>100 μg/mL) of erythromycin, spiramycin and the lincosamides but were sensitive to dalfopristin, an analogue of streptogramin B. Interestingly, the high-passage erythromycin-resistant strain B31 was resistant to quinupristin, an analogue of streptogramin A (25 μg/mL). Biochemical analysis revealed that resistance was not due to antibiotic inactivation or energy-dependent efflux but was instead due to modification of ribosomes in these isolates. Interestingly, we were able to demonstrate high-frequency transfer of the resistance phenotype via conjugation from B. burgdorferi to Bacillus subtilis (10⁻²–10⁻⁴) or Enterococcus faecalis (10⁻⁵). An intergeneric conjugal system in B. burgdorferi suggests that horizontal gene transfer may play a role in its evolution and is a potential tool for developing new genetic systems to study the pathogenesis of Lyme disease.     

Functional motor recovery from brain ischemic insult by carbon nanotube-mediated siRNA silencing

Stroke is the second cause of death worldwide with ischemic stroke accounting for 80% of all stroke insults. Caspase-3 activation contributes to brain tissue loss and downstream biochemical events that lead to programmed cell death after traumatic brain injury. Alleviation of symptoms following ischemic neuronal injury can be potentially achieved by either genetic disruption or pharmacological inhibition of caspases. Here, we studied whether silencing of Caspase-3 using carbon nanotube-mediated in vivo RNA interference (RNAi) could offer a therapeutic opportunity against stroke. Effective delivery of siRNA directly to the CNS has been shown to normalize phenotypes in animal models of several neurological diseases. It is shown here that peri-lesional stereotactic administration of a Caspase-3 siRNA (siCas 3) delivered by functionalized carbon nanotubes (f-CNT) reduced neurodegeneration and promoted functional preservation before and after focal ischemic damage of the rodent motor cortex using an endothelin-1 induced stroke model. These observations illustrate the opportunity offered by carbon nanotube-mediated siRNA delivery and gene silencing of neuronal tissue applicable to a variety of different neuropathological conditions where intervention at well localized brain foci may offer therapeutic and functional benefits.