Ex vivo identification of atherosclerotic plaque calcification by a 31P solid-state magnetic resonance imaging technique.

Calcified tissue is a common component of atherosclerotic plaques, and occurs most often in mature plaques. The process of calcification is a poorly understood risk factor that may contribute to a plaque's vulnerability to sudden rupture. In this study a solid-state imaging sequence, termed single-point imaging (SPI), was used to observe calcification directly in ex vivo atherosclerotic plaques. Standards were used to validate the ability of (31)P SPI to detect and differentiate calcification from crystalline cholesterol, phospholipids, and other plaque components. After suitable experimental parameters were found, human carotid specimens obtained by endarterectomy were imaged ex vivo by (31)P solid-state imaging and standard (1)H methods. In contrast to (1)H imaging methods, (31)P imaging detected only the calcification in the plaque.     

Cranial nasal bone grafts

Reconstitution of the nasal scaffolding with maintainence of soft tissue proportions either following severe facial trauma or as a sequela to aesthetic rhinoplasty misadventures frequently is best achieved using the stability afforded by bone grafts. Split cranial bone grafts offer many advantages and may be the donor site of choice, and may even allow such surgery to be performed on an outpatient basis in some cases. The use of miniplate or screw osteosynthesis, now commonly accepted as a superior technique in craniomaxillofacial procedures, may simplify fixation of these calvarial nasal bone grafts with an apparent decrease in the risk of resorption.     

Preliminary assessment of laser Doppler flowmetry for determining timing of division of the cross-finger flap

The elapsed time before division of the cross-finger flap depends on adequate neovascularization from the recipient digit. Although subjective assessment of capillary filling in the flap after application of a tourniquet to the donor finger usually is accurate, on occasion, interpretation of observations may be equivocal. In these circumstances, noninvasive office measurement with use of the laser Doppler permits a sequential determination of relative flap perfusion. This objective data facilitates an appropriate clinical decision by the hand surgeon to ensure flap viability after pedicle division.     

Miniplate washers for improving lag screw fixation

Increased efficiency in using the lag screw principle for rigid fixation of bone, particularly for fragile cortical or soft cancellous grafts, is facilitated by dispersion of screw head compression forces with a biocompatible metallic washer. Although none is commercially available, such washers may be quickly fashioned from the residua of any adaptation miniplate in quantities as required.     

Recognition of potential morbidity after use of the radial artery as a conduit for coronary artery revascularization

The use of the radial artery as an alternative vascular conduit for coronary bypass surgery has become increasingly popular. The plastic surgery experience with radial forearm flaps has shown that sacrifice of the radial artery is not always a benign maneuver. The potential morbidity after using this conduit donor site in terms of hand dysfunction or wound healing problems can be significant, and frequently must ultimately be addressed as part of the role of the reconstructive surgeon. Case examples of skin necrosis, subsequent forearm wound infection and hypertrophic scarring after radial artery harvest are presented to introduce this as a real concern and to allow a review of the entire spectrum of potential problems in this regard. Any selection process where the radial artery may be chosen as the coronary revascularization conduit must anticipate these known donor site complications.     

Mortality studies of machining fluid exposure in the automobile industry III: A case-control study of larynx cancer

A case-control study of larynx cancer was conducted within a cohort of automobile workers exposed to metal working fluids, commonly referred to as machining fluids (MF). Results are based on 108 cases of larynx cancer and 5:1 matched controls. Risks associated with specific types of MF, as well as specific components of the fluids were evaluated. Based on a retrospective exposure assessment, lifetime exposures to straight and soluble fluids, grinding particulate, biocides, selected metals, sulfur, and chlorine were examined. Exposure to asbestos and acid mists at two of the three study sites was also characterized. Results suggest that straight mineral oils are associated with almost a two-fold excess in larynx cancer risk. There was also evidence of an association with elemental sulfur, commonly added to straight MF to improve the integrity of the materials under extreme pressure and heat. It is not clear whether sulfur is causally related to an excess relative risk of larynx cancer or whether the observed association is the result of unmeasured confounding by another contaminant or process feature. For example, the high stress operations that require MF enriched with sulfur are also more likely to produce polycyclic aromatic hydrocarbons (PAHs) during the process. Thus, the observed association with sulfur may be due to an association with PAH. The finding of excess risk of laryngeal cancer associated with MF is consistent with several previous reports in the literature. This is the first study, however, to distinguish straight mineral oils from other types of MF. Based on these findings, a general reduction in concentrations of straight mineral oil particulate in occupational environments would be prudent.     

Bipedicled fasciocutaneous flaps in the lower extremity.

It is well known that a bipedicled skin flap permits survival of longer flaps due to the secondary recruitment of vascularity. Inclusion of the deep fascia with such a flap, obeying the principles of the single-pedicled fasciocutaneous flap, provides even greater security for the immediate transposition of yet larger or riskier flaps without the need for delay maneuvers. This variation is especially valuable for the management of difficult wounds encountered in the lower extremity when no other local options may be available. Thirteen local bipedicled fasciocutaneous flaps including both vertical and horizontal orientations, without isolation of any discrete fascial perforators, have been successfully used for soft tissue coverage in the distal leg and ankle with only three (23%) minor complications as untoward sequelae. Another major advantage of this bipedicled version of the fasciocutaneous flap was that the inclusion of a distal pedicle simultaneously may be designed to prevent bone or tendon exposure at the donor site that otherwise frequently is a concern with a unipedicled flap.     

Closure of the ulnar forearm free flap donor site using a local radial forearm flap.

Thin, pliable cutaneous flaps with large calibre vessels ideal for microsurgical transfers are major attributes of the reliable forearm fasciocutaneous flaps. A major detriment, however, that must always be considered is the management of the residual donor site deformity. Just as this potential morbidity for small radial forearm free flap donor sites may be minimised by the V-Y advancement of a local ulnar forearm flap, the converse, using a local radial forearm flap for closure of the ulnar forearm free flap donor site, may be efficacious.     

Mortality studies of machining-fluid exposure in the automobile industry. II. Risks associated with specific fluid types.

Excesses of digestive and respiratory cancers have been reported previously in association with exposure to machining fluids, agents in widespread use as coolants and lubricants in machining operations. Previous studies have had limited power to distinguish the effects of the different types of machining fluids in use. In a cohort of over 30,000 workers employed at two automotive plants in Michigan, mortality patterns were studied in relation to exposure to each of the three major fluid types--straight oils, soluble oils, and synthetic fluids. Standardized mortality ratios were estimated for subgroups of the cohort ever exposed to each of the three fluid types, and Poisson regression analyses were used to assess trends in risk with duration of exposure. The data suggest modest positive associations between exposure to straight oils and rectal, laryngeal, and prostatic cancer and a negative association between soluble and synthetic fluid exposure and lung cancer.     

Gene conversion is a likely cause of mutation in PKD1

Approximately 70% of the gene responsible for the most common form of autosomal dominant polycystic kidney disease ( PKD1 ) is replicated in several highly homologous copies located more proximally on chromosome 16. We recently have described a novel technique for mutation detection in the duplicated region of PKD1 that circumvents the difficulties posed by these homologs. We have used this method to identify two patients with a nearly identical cluster of base pair substitutions in exon 23. Since pseudogenes are known to be reservoirs for mutation via gene conversion events for a number of other diseases, we decided to test whether these sequence differences in PKD1 could have arisen as a result of this mechanism. Using changes in restriction digest patterns, we were able to show that these sequence substitutions are also present in N23HA, a rodent-human somatic cell hybrid that contains only the PKD1 homologs. Moreover, these changes were also detected in total DNA from several affected and unaffected individuals that did not harbor this mutation in their PKD1 gene copy. This is the first example of gene conversion in PKD1 , and our findings highlight the importance of using gene-specific reagents in defining PKD1 mutations.