Neck contour deformities. The art, engineering, anatomic diagnosis, architectural planning, and aesthetics of surgical correction

The best quality long-lasting results require attention to the diagnosis of the precise anatomic problems followed by the architectural planning--the art of making beautiful highlights, shadows, and curves where indicated to produce a result that is aesthetically pleasing. Attention to the details of the surgical planning, execution of surgery, and postoperative care are essential to minimize untoward results and problems and produce a happy patient and pleased surgeon.     

Continuous 4-channel EEG monitoring: a guide to interpretation, with normal values, in preterm infants

A system is described for the rapid analysis of the extensive EEG data produced by continuous 4-channel monitoring. Using this system, the initial EEGs of 44 low-risk preterm infants between 26 and 37 weeks gestation have been analysed and quantified in order to establish standard values. This provides a basis for assessment of the acute EEG as an index of cerebral function in high-risk or abnormal preterm infants.     

Mechanism and prediction of nonspecific toxicity to fish using bioconcentration characteristics

A basic theory of nonspecific toxicity has been developed using bioconcentration as a basis and applying kinetic relationships developed in previous work. This approach has involved calculation of the critical volume fraction and critical concentration in lipid tissue of fish for a variety of organic compounds at the lethal level. Corrections to previous data sets for time period of exposure and inclusion of biodegradable compounds did not make a significant improvement in the values obtained. A new data base with compounds containing a wide range of Kow values gave results for critical volume and concentration similar to previous work. The influence of experimental procedures and methods for data development are considered. The basic theoretical derivation developed was found to provide a basis for predicting the approximate nonspecific toxicity of nondegradable lipophilic organic compounds at different exposure time periods. This requires a knowledge of the Kow value and the clearance rate constant (k2) which can be calculated from the Kow value.     

Preoperative localization of low-density foreign bodies under CT guidance

A simple technique for the localization of foreign bodies using a spring hook wire under computed tomographic (CT) guidance is described. The advantages of CT in detecting foreign bodies of near water density and in planning a surgical approach which avoids important anatomical structures are emphasized.     

Requirement for ICR-like sequences in the replication of brome mosaic virus genomic RNA.

Previous studies using a brome mosaic virus (BMV) RNA-2 deletion mutant (pRNA-2 M/S) and additional derivatives as reporters established that viral sequences resembling internal control regions (ICRs) 1 and 2 of tRNA gene promoters are vital to (+)-strand replication in protoplasts. Transfer of these mutations to genomic RNA-2 and functional analysis in protoplast, local lesion, and systemic infections revealed a sequence-specific requirement for bases within the ICR2-like motif. Despite the low (generally less than 20% of wild-type) and sometimes undetectable levels of replication of these RNA-2 mutants, sufficient p2a protein was produced to support at least modest levels of RNA-1, -3 and -4 replication in protoplasts. However, only those RNA-2 ICR2 mutants supporting substantial replication of the viral genome in protoplasts were capable of establishing local lesions in Chenopodium hybridum and systemic infections in barley, further establishing the essential role of the ICR-like sequences in viral infectivity. Upon passage through a second set of barley plants, accumulation patterns for progeny from inocula containing certain RNA-2 mutants paralleled those from wild-type inocula, indicating repair of the introduced mutations. RNA stability and translatability were shown to be unaffected by the introduced mutations. BMV RNA-3 contains several ICR-like sequences, each of which was individually deleted. Whereas deletion of the 5'-terminal ICR2-like motif had little effect on RNA-3 accumulation in protoplasts or local lesion formation, it debilitated systemic spread in barley. Deletion of an internal ICR2-like motif at position 1100 decreased (+):(-) strand asymmetry from greater than 100:1 to 14:1, reduced RNA-3 replication in protoplasts to less than 15% of wild-type, and abolished local lesion and systemic infectivity.     

Three-dimensional reconstruction of magnetic resonance images of the temporomandibular joint by I-DEAS.

Evaluation of the temporomandibular joint has been limited by the inability of current technology to image complex morphology and motion in three dimensions. An engineering design program, I-DEAS, has been used to construct solid models from magnetic resonance images. A dried skull with an acrylic resin temporomandibular disc replica, immersed in water, provided sagittal and coronal MR images. Linear dimensions and disc volumes obtained from the models were compared with the original and found to be consistent, within the limits imposed by the slice thickness. We have applied the method to the living joint in an asymptomatic volunteer, and report our initial experience in demonstrating the spatial relationships and motion of the joint components.     

Laser-assisted transluminal angioplasty of the superficial femoral and popliteal arteries

During an initial 1-year experience with percutaneous laser-assisted balloon angioplasty at the Vancouver General Hospital, 9 of 61 patients considered suitable for intervention because of arterial occlusive disease were selected for laser treatment. The neodymium-YAG laser with a contact sapphire tip was chosen because the probes and tips are reusable, thereby reducing the cost per patient. The patients had either severe limiting claudication or pain at rest, involving the superficial femoral or popliteal artery. One of the patients had lesions in both legs, making a total of 10 lesions. In 8 of the 10 lesions, treatment initially was successful. In the other two instances, the laser perforated the arterial wall, but the patients suffered no ill effects; repair by bypass surgery was uncomplicated. Another patient had distal thrombosis at the time of angioplasty of the popliteal artery; this responded to fibrinolytic therapy and subsequent balloon angioplasty of the peroneal artery. The initial 80% success rate was reasonable, considering that all these patients would otherwise have undergone bypass surgery. One patient had recurrent stenosis 5 months after the procedure. The other seven had good results with relief of symptoms. However, follow-up has been short (mean 4.9 months), the longest being only 11 months.