Let-7 microRNAs are developmentally regulated in circulating human erythroid cells

Background

MicroRNAs are ~22nt-long small non-coding RNAs that negatively regulate protein expression through mRNA degradation or translational repression in eukaryotic cells. Based upon their importance in regulating development and terminal differentiation in model systems, erythrocyte microRNA profiles were examined at birth and in adults to determine if changes in their abundance coincide with the developmental phenomenon of hemoglobin switching.

Methods

Expression profiling of microRNA was performed using total RNA from four adult peripheral blood samples compared to four cord blood samples after depletion of plasma, platelets, and nucleated cells. Labeled RNAs were hybridized to custom spotted arrays containing 474 human microRNA species (miRBase release 9.1). Total RNA from Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines provided a hybridization reference for all samples to generate microRNA abundance profile for each sample.

Results

Among 206 detected miRNAs, 79% of the microRNAs were present at equivalent levels in both cord and adult cells. By comparison, 37 microRNAs were up-regulated and 4 microRNAs were down-regulated in adult erythroid cells (fold change > 2; p < 0.01). Among the up-regulated subset, the let-7 miRNA family consistently demonstrated increased abundance in the adult samples by array-based analyses that were confirmed by quantitative PCR (4.5 to 18.4 fold increases in 6 of 8 let-7 miRNA). Profiling studies of messenger RNA (mRNA) in these cells additionally demonstrated down-regulation of ten let-7 target genes in the adult cells.

Conclusion

These data suggest that a consistent pattern of up-regulation among let-7 miRNA in circulating erythroid cells occurs in association with hemoglobin switching during the fetal-to-adult developmental transition in humans.

Competitive forces and academic plastic surgery

Economic constraints developing as a result of rising health care costs in the United States pose significant challenges for and threats to the survival of academic plastic surgery. Declining clinical revenues, competition for patients and resources from other health care providers, and reductions in support of its education and research efforts necessitate a paradigm shift if it is to survive. Questionnaires were used to collect data from 92 of the 100 postgraduate training program directors of plastic surgery in the United States. The most common source of clinical income on a national basis was indemnity insurance. Sources of clinical income varied by region. The majority of programs, 80 percent, report that at least 75 percent of the income support for faculty came from practice income. Financial support for ancillary and research personnel, in large part, came from this same source. Resident salaries and benefits came largely from other resources. Generally as population density within the metropolitan area in which a program was located increased, so too did the number of competing plastic surgeons, including graduates of the program and nonacademic cosmetic and hand surgeons. However, levels of competition for cosmetic surgery in smaller metropolitan areas of some regions seem to be similar to those reported by programs in larger communities. Plastic surgery programs in very competitive communities received significantly greater amounts of their income from indemnity insurance and self-paying patients than did programs in less competitive metropolitan areas. Internal competition from other surgical and nonsurgical specialists within the same institution is likewise keen. Virtually all respondents, 93 percent, report that their institutions provided patient care in a least one designated center of excellence in the following disciplines: hand, microsurgery, craniofacial, cleft lip and palate, burn, and cosmetic surgery. This study suggests that centers of excellence are more likely to be present in metropolitan areas with fewer competing surgeons than in areas with large numbers of competing surgeons. The data did not demonstrate that the presence of a center of excellence substantially affected the sources or levels of clinical income. To survive as an academic entity, program directors must correctly perceive and fulfill the needs and wants of its stakeholders, particularly with regard to quality of life issues.

Tissue repair after Mohs surgery. A plastic surgeon's view

BACKGROUND

Goals of the treatment for skin cancer include completeness of removal of the lesion, minimal functional disability, and a good aesthetic result. With increasing standards for the quality assurance and the demand for cost-effectiveness, assessment of resource-consuming treatment modalities, especially those involving multidisciplinary approaches, seems appropriate.

OBJECTIVE

The purpose of this study was to review the strategy of management and the approaches to tissue repair following cutaneous micrographic surgery from the plastic surgeon's point of view.

METHOD

Retrospective review of personal experience based on approximately 800 patients treated between 1989 and 1996 and current plastic surgery literature.

RESULTS AND CONCLUSIONS

Teamwork with the Mohs surgeon, recognition of the post-Mohs' procedure wound components, and familiarity with reconstructive techniques are essential for the multidisciplinary practice success. The pitfalls of the reconstructive approaches are discussed.

New trends in skin tumor surgery

Over 8 years, 1700 patients were referred from the Mohs' Surgery and Cutaneous Laser Unit after Mohs micrographic skin tumor excision to the Division of Plastic and Reconstructive Surgery. Preoperative coordination between the two divisions was emphasised in wound preparation and timing of reconstruction for maximized patient convenience and outcome. Most repairs of facial and extremity defects were carried out under local anesthesia. Techniques of repair were selected based upon algorithmic priorities emphasizing simple techniques over complex ones. Direct closure, skin grafts and flaps were used. Preference for aesthetic subunit reconstruction of the face and the use of particular flap techniques including the O-to-S, O-to-T, V-to-Y island advancement, islandized nasolabial flap for alar reconstruction and the forehead flap for nasal dorsum and tip repair are illustrated.

Transmissibility of live Mycoplasma gallisepticum vaccine strains ts-11 and 6/85 from vaccinated layer pullets to sentinel poultry

In separate trials, layer pullets were vaccinated with Mycoplasma gallisepticum (MG) strain 6/85 or strain ts-11 commercially produced live vaccines. For a 15-wk postvaccination (PV) period, vaccinates were commingled with unvaccinated pullets and were in indirect contact with sentinel groups of pullets, broiler breeders, turkey breeders, or meat turkeys in adjoining pens. Infectivity and transmissibility of vaccine strains were determined by tracheal culture and serology at 1 wk followed by 3-wk intervals PV. Strain 6/85 was recovered from 0%-20% of vaccinates, but not from commingled pullets or sentinel birds. Strain ts-11 was recovered from 60%-90% of vaccinates and 0%-40% of commingled pullets but not from any of the sentinel birds. No birds in the 6/85 vaccine trial tested positive for MG antibodies by serology. MG enzyme-linked immunosorbent assays detected positive responses in ts-11 vaccinates (range = 10%-70%) at 42, 63, 84, and 105 days PV, and commingled pullets (10%) at 84 and 105 days PV. MG serum plate agglutination tests detected positive responses in 90% and 20% of ts-11 vaccinates at 42 and 105 days PV, respectively, and commingled pullets (10%) at day 42 PV. Clinical signs, morbidity, or mortality suggestive of pathogenic MG infection were not observed in any bird during either trial, and no gross lesions were observed at necropsy. Random amplified polymorphic DNA analysis was capable of distinguishing each of the vaccinal strains 6/85 and ts-11 from each other by their distinct DNA banding patterns.

Infectious bursal disease viral RNA amplification using RT/PCR from bursa tissue following phenol: chloroform inactivation of the virus

The preservation of viable infectious agents for future studies could create complicated logistic problems, and at times it is not feasible. Methods for preserving the genetic integrity of inactivated agents would not only facilitate these studies but would also make it possible to transport inactivated preparations around the world. In this report, the effect of inactivation on the genetic material of infectious bursal disease virus (IBDV) was studied. Tissues from the bursa of Fabricius of birds experimentally infected 3 days earlier with the classic STC strain of IBDV were collected and immediately placed in a solution of phenol:chloroform:isoamyl alcohol (25:24:1) for 24, 48, 72, or 96 hr. Infected bursal tissue not treated with the phenol:chloroform solution and uninfected phenol: chloroform bursal tissue were used as controls. In a separate experiment, bursal tissues collected 5 days following infection of specific-pathogen-free birds with the classic STC or variant 1084-E strain were placed in the phenol:chloroform solution for 2 wk. All bursal samples were tested for viable IBDV following phenol:chloroform treatment. The tissues were washed in phosphate-buffered saline to remove phenol and then homogenized. Viability of the viruses in homogenized bursal tissue was examined by inoculation of embryonated chicken eggs. Viable IBDV was not observed in any phenol:chloroform-treated bursal tissue but was observed in the infected but non-phenol:chloroform-treated control bursa. The reverse transcriptase/polymerase chain reaction (RT/PCR) was used to test the integrity of the viral RNA. Viral RNA from the nontreated control and all infected bursal samples treated with phenol:chloroform solution at all the time points examined were transcribed into DNA, and a 394-bp fragment of the VP2 gene was amplified using specific primers in the PCR. The RT/PCR assay was negative using the phenol:chloroform-treated uninfected bursal tissue. This study clearly demonstrated that phenol:chloroform treatment of infected bursal tissue inactivated the classic and variant IBDV strains tested and preserved the viral RNA for use in the RT/PCR assay.

Pharmacodynamic modeling of the antihypertensive response to amlodipine

The distinctive pharmacokinetic characteristics of amlodipine, particularly the long half-life, are presumed to translate directly to a prolonged duration of action, but the concentration-effect relationship for the antihypertensive response has not been clearly established. In this study of 12 patients with essential hypertension, treatment with 5 mg amlodipine once daily has been evaluated with use of an integrated pharmacokinetic-pharmacodynamic model to calculate individual patient responsiveness for the decrease in blood pressure per unit change in drug concentration. Amlodipine concentrations were well correlated with the placebo-corrected reductions in blood pressure in individual patients and responsiveness, for example, for erect systolic blood pressure was -3.1 +/- 0.9 mm Hg/ng/ml. By characterizing the concentration-effect relationships in individual patients, this study has confirmed that the plasma concentration-time profile is an appropriate index of the effect-time profile, as reflected by an antihypertensive response that is sustained throughout 24 hours with relatively little trough-to-peak variability.

Spect brain imaging in neurologic disease

In recent years cerebral SPECT imaging is rapidly evolving as a clinical tool in the evaluation of a variety of neurologic disorders. In large part, the major advances in brain imaging which have occurred in the last four years are related to new developments in instrumentation and radiopharmaceuticals. In particular, the increased availability of multidetector and dedicated ring detector systems has given rise to improved image resolution and more rapid patient throughput. Advances in the field of radiopharmaceutical development, particularly as it pertains to perfusion brain SPECT agents, has also contributed to the advances in the field. As a result of these developments, there has been an expanded interest in and use of brain SPECT imaging procedures in the evaluation of cerebrovascular disease, dementia, epilepsy, and head trauma.

Reconstruction after Mohs cancer excision

At our institution, 363 skin defects following Mohs excision for carcinoma were repaired in a two-year period. The majority of the patients were women (62%). Most repairs were to the nose (42%), and almost all followed basal cell carcinoma excision (91% of tumor types). Flaps were preferable to skin grafts for facial repair, with forehead and nasolabial flaps particularly useful for the nose. Injection of Kenalog (triamcinolone acetonide, 5-20 mg/mL) speeds the maturation of scars and flaps.

Consumer satisfaction survey: an outcome measure for work services

This article describes a consumer satisfaction survey of work services in a community mental health center. The development of a satisfaction survey tool is discussed, the results from 41 respondents are given, and the implications of the survey's results are outlined.

Gastric lesions in the excluded gastric segment undetected by endoscopy or radiography in patients status post vertical banded gastroplasty

A patient had two surgical revisions and another patient had one surgical revision of a vertical banded gastroplasty because of intraoperative findings of gastric ulceration, incomplete penetration, and transmural penetration of the silicone band. Preoperative esophagogastroduodenoscopy in all three cases and an upper gastrointestinal series in two of the cases failed to demonstrate these lesions, because the lesions were located in the surgically excluded gastric segment. These reports demonstrate that a normal upper gastrointestinal series or panendoscopy in a patient after vertical banded gastroplasty does not exclude significant lesions in the endoscopically inaccessible, excluded gastric segment, and that it may be necessary to perform a laparotomy on a severely symptomatic patient even when an endoscopy is normal.

Complications of nasoenteral tubes. Intragastric tube knotting and intragastric tube breakage

We report two complications of nasoenteral tubes. A nasogastric tube became knotted during gastric intubation in a patient with a small gastric remnant, created during gastric surgery for morbid obesity. A clogged Dobbhoff tube ruptured while it was being flushed manually with a syringe containing normal saline under great pressure. To retrieve the knotted tube, we grasped the distal knotted part visible in the oropharynx with forceps, pulled it out of the mouth, and cut it. To retrieve the broken tube, we snared the intragastric fragment at endoscopy. These case reports suggest that a small gastric remnant may be a risk factor for nasogastric tube coiling and knot formation and that flushing a clogged tube at high pressure may rupture it. To prevent these complications, a nasogastric tube should be carefully passed just into the stomach in a patient with a small gastric remnant, and a clogged feeding tube should be flushed with only moderate pressure. Failure to clear a blocked tube by flushing with normal saline at moderate pressure should lead to tube removal and not to use of excessive pressure.

Do forehead lifts lift or unfurl?

Forehead lifts are becoming increasingly more popular as an adjunct to facial rejuvenation. Considerable confusion exists as to how much the eyebrow should be elevated and how much scalp should be removed to achieve this goal. In an effort to evaluate this question, we have reviewed our recent forehead lift experience. These were done with forehead flap dissection down to glabella and supraorbital ridge, partial resection of corrugator supercilii, procerus, and frontalis muscles, and limited skin resection. We suggest that a natural-appearing, rejuvenating forehead lift should unfurl facial wrinkles without excessive eyebrow elevation. Technical maneuvers to obtain this goal are discussed.

Studies with abanoquil (UK-52,046) a novel quinoline alpha 1-adrenoceptor antagonist: II. Duration of action, pharmacokinetics and concentration-effect relationships in normotensive subjects

1. This study further examines the quinoline-derivative abanoquil with particular respect to the duration of its alpha 1-adrenoceptor antagonist activity and its concentration-effect relationship following a single intravenous bolus dose of 0.5 micrograms kg-1 in young, normotensive males. 2. alpha 1-adrenoceptor antagonism (as assessed by phenylephrine pressor responses) was detectable for up to 12 h post dosing: at 12 h there was a significant 1.5-fold rightward shift (95% CI: 2.2 to 1.1) of the pressor dose-response curve for diastolic blood pressure. 3. Despite evidence of substantial alpha 1-adrenoceptor antagonism abanoquil had no significant effect on blood pressure, supine and erect, but there were small and statistically significant increments in heart rate. 4. The degree of alpha 1-adrenoceptor antagonism was related to whole blood concentrations abanoquil: the PD-ratios of phenylephrine pressor responses performed at 1, 6, and 12 h post dosing were significantly correlated with log drug concentrations (r = 0.57 for systolic (P less than 0.05) and r = 0.78 for diastolic blood pressure (P less than 0.005). 5. In conclusion, abanoquil produced significant alpha 1-adrenoceptor antagonism which was related to circulating drug concentrations. The absence of other significant cardiovascular effects suggests that abanoquil warrants further clinical study as an antiarrhythmic agent.

Chronic swim stress enhances the motoric inhibiting effects of a muscarinic agonist

The authors previously demonstrated that chronic inescapable swim stress and footshock increase the capacity of a fixed dose of a muscarinic agonist to produce hypothermia in the rat. This project was designed to determine whether chronic inescapable swim stress in cold water would render a low dose of a muscarinic agonist, devoid of an effect on motor behavior in the naive rat (i.e., prior to subjection to the course of swim stress), an inhibitor of mobility. The study involved two groups of rats, an experimental group which received arecoline and a control group which received saline five minutes prior to being placed in an open field. Number of crossings, the dependent variable, was measured in both groups before and after a 14-day course of twice daily inescapable swim stress of 10 minutes duration at 12 degrees C. The arecoline-treated group, as hypothesized, exhibited a significantly greater reduction in number of crossings than the saline-treated groups following the course of swim stress.

Healing in the irradiated wound

Poor or nonhealing of irradiated wounds has been attributed to progressive obliterative endarteritis. Permanently damaged fibroblasts may also play an important part in poor healing. Regardless of the cause, the key to management of irradiated skin is careful attention to prevent its breakdown and conservative, but adequate, treatment when wounds are minor. When wounds become larger and are painful, complete excision of the wound or ulcer is called for and coverage should be provided by a well-vascularized nonparasitic distant flap.

Effectiveness of prophylactic mastectomy in the prevention of breast tumors in C3H mice

The effectiveness of prophylactic mastectomy in the prevention of breast tumors was studied in spontaneous breast-tumor-forming C3H mice. Prolactin levels were assayed to determine if this hormone was related to the incidence of mammary tumors. Two-hundred and fifty-six 1-month-old C3H mice were divided into four groups (control, 1; sham surgery, 2; mammectomy 50 percent, 3; and mammectomy 100 percent, 4). At the time of sacrifice (0 to 1 year postoperatively) estrus cycles were determined, ventral skin (breast) and ovaries were removed for histology, and serum was collected for prolactin assays. Prolactin levels 24 hours postoperatively were significantly elevated (p less than 0.01) in groups 2 to 4 when compared with group 1. Six months postoperatively, prolactin levels were significantly higher (p less than 0.05) in mice with tumors compared with those without tumors in groups 3 and 4. There were no differences in tumor incidence between the four groups. At 12 months postoperatively, no differences in prolactin levels were noted, but group 2 animals had the highest incidence of mammary tumors (89 percent; p less than 0.01) when compared to groups 3 and 4. Mammary tumor incidence was not decreased by 50 percent or 100 percent mammectomy in C3H mice. Prolactin levels rose in response to surgery and/or anesthesia and remained elevated only in tumor-bearing mice who underwent mammectomy, an occurrence similar to that reported in humans.

Improved imaging of the augmented breast

The breast containing an augmentation implant presents a challenge to the mammographer and is often considered unsuitable for adequate mammographic evaluation. A modified positioning technique is described. By displacing the implant posteriorly against the chest wall and pulling breast tissue over and in front of the implant, marked improvement in compression and visualization of substantially more breast tissue is achieved. Over 250 patients with augmentation implants have been successfully studied with this modified compression technique. After review of 50 consecutive cases, two experienced mammographers confirmed a significant improvement in image quality, amount of breast tissue visualized, and overall benefit of the modified technique. Modified positioning for women with breast implants substantially improves both image quality and amount of breast tissue imaged.

Effects of phenylephrine on tissue gas tension, bleeding, infection, and lidocaine absorption

In an attempt to find a vasoconstrictor with less detrimental local and systemic effects than epinephrine, the effects of phenylephrine, a pure alpha agonist, on tissue gas tension, bleeding, infection rates, and lidocaine absorption were studied. All concentrations of phenylephrine significantly reduced tissue PO2 within 10 minutes of injection, and reduction of PO2 was dose-dependent. Phenylephrine 1:10,000 produced significant bacterial growth when simultaneously injected with 6 X 10(6) Staphylococcus aureus. Bacterial growth was insignificant with 1:20,000 phenylephrine and absent with 1:40,000 phenylephrine. Blood loss from a standard wound was significantly reduced at all concentrations of phenylephrine. Lidocaine absorption was significantly reduced with 1:20,000 and 1:40,000 phenylephrine. In a rat model, 1:40,000 phenylephrine significantly reduced blood loss and lidocaine absorption, produced minimal reduction of tissue PO2, and did not enhance bacterial invasion.

The effect of food on the absorption of slow-release isosorbide-5-mononitrate tablets

The influence of food on the absorption characteristics of slow release isosorbide-5-mononitrate tablets was investigated in 10 normal healthy volunteers. There were no differences in the peak concentration achieved or the area under the curve, but the peak concentration occurred later when the drug was administered after food. The apparent elimination half-life ranged from 4.7 to 10.1 h. Bioavailability of slow-release isosorbide-5-mononitrate is therefore unaffected by food, but there is a slower rate of absorption.

Craniofacial biostereometrics

We believe that biostereometrics can be useful to the craniofacial surgeon in providing a highly accurate, reproducible diagnostic and presurgical tool that is inexpensive and noninvasive. It can help visualize complex pathologic bony abnormalities, resolve ambiguous CT scans, and predict soft-tissue changes secondary to alterations in bony contours when used in conjunction with CT scans and cephalograms.

Management of burned long bones

The management of severely burned and exposed supportive osseous tissues is not fully standardized. We present two patients in whom extensive debridement and decortication of the involved bone may have contributed to subsequent stress fractures. We propose an alternative therapeutic approach for this problem, including: minimal debridement of the bone, early coverage of the exposed bone with vascularized muscle, and adequate prophylactic protection.

Attempts to improve tissue survival during ex vivo storage

Ex vivo hypothermic perfusion has been shown to enhance short-term survival of organs before transplantation. The effects of perfusion, control of media pH, and systemic drug treatment were studied utilizing superficial epigastric free flaps in Sprague-Dawley rats. Viability of the flaps could be reliably maintained (9/10, 90%) for 72 hours using simple storage in phosphate-buffered Ringer's (pH 7.8) at 4 degrees C. Pretreatment with prostaglandin E1 was of slight benefit. Flap perfusion with or without pharmacologic agents was not beneficial.

Juvenile aponeurotic fibroma with disseminated fibrosarcoma

Juvenile aponeurotic fibromas, although locally recurrent, generally do not metastasize. This observation supports the practice of incomplete excision of the tumor to preserve the function of the involved extremity. We report on a patient with a juvenile aponeurotic fibroma of the palm, who returned 5 years after the second local surgical excision with metastatic fibrosarcoma of the lungs and bones.

Use of ultrasound to locate a "lost" tissue expander injection port

We have presented a rapid and reliable method of finding lost injection valves. (A frustrating footnote, however, is that 1 week later the port had again migrated and could not be located. Since the further anticipated gain was marginal, the bladder was already nearly expanded, and the expense for repeated ultrasound was a consideration, no further attempts were made to locate this port by ultrasound for further filling).

Tissue expansion as an adjunctive technique for the management of difficult wounds

Replacement of lost or injured tissues with similar tissues is a major goal of the reconstructive surgeon. A relatively new modality, tissue expansion, appears to be an helpful adjunct in achieving this goal by providing tissues for reconstruction that are near at hand, possess similar characteristics to the lost tissue, and can even enhance vascularity within an ischemic area. Although the technique is a useful one, its indications and contraindications are incompletely defined. We have used this technique 65 times in 42 patients during a 2 1/2 year period. The overall complication rate has been 22 percent, similar to other reconstructive techniques, but the consequences of these complications have been relatively minor and have not, for the most part, added significantly to patient morbidity.

Repeated skin expansion to resurface a massive thigh wound

We report here a patient who sustained posttraumatic skin and soft-tissue loss of the right thigh. Replacement of approximately 750 cm2 of split-thickness skin graft with adjacent skin serially expanded and advanced demonstrates the applicability of this technique to cover large tissue defects. Despite infection and exposure, we believe that expansion can proceed safely on an outpatient basis, providing that systemic toxicity does not develop and the exposure does not mechanically preclude expansion.

Hemodynamic alterations secondary to an electrical burn in the rat: a pilot study

Rats subjected to a standard electrical burn of 250 volts for 10 seconds receive a severe injury stimulating a pronounced systemic circulatory response. Initial postinjury hyperemia is replaced by a low perfusion state within 24 hours. Our study demonstrates the difficulty in isolating regional microcirculatory alterations under such circumstances. Modification of the burn model or the method of fluid resuscitation may minimize the influence of this dynamic systemic response.

Analysis of the risk reduction of prophylactic partial mastectomy in Sprague-Dawley rats with 7,12-dimethylbenzanthracene-induced breast cancer

The effectiveness of prophylactic mastectomy in preventing breast cancer was studied in female albino Sprague-Dawley rats. Group A served as untreated controls. Groups B, C, and D underwent 50%, 75%, and total mastectomies 2 weeks after the administration of 7,12-dimethylbenzanthracene (DMBA). Group E was initially subjected to total mastectomy. Two weeks after surgery, group E received 5 mg of DMBA intravenously. Group F underwent sham procedures. All animals were sacrificed at age 8 months. The mean number of tumors per animal developing in groups A through E was 5.00, 5.17, 4.67, 5.46, and 5.20, respectively. There was 0.21 tumor per animal in group F. The mean time to tumor development in groups A through E was 11.33, 10.05, 9.88, 19.25, and 19.38 weeks, respectively. All results were subjected to an analysis of variance. There was no statistically significant difference in the number of DMBA-induced tumors in groups A through E. Groups D and E had a significant prolonged time to tumor development. The overall risk of the development of breast tumors was not significantly reduced by prophylactic mastectomy. Residual breast tissue after prophylactic mastectomy is at increased risk for the development of breast tumors. The risk of developing breast tumors in this model is not reduced in proportion to the amount of breast tissue removed. (This study suggests that subcutaneous mastectomy in high-risk individuals may not have appropriate prophylaxis against the development of carcinoma of the breast.)

Potentiation of infection by epinephrine

A subinfective dose of Staphylococcus aureus (6 X 10(6)) does not produce wound infection in the rat model. Reducing the dosage (concentration) of epinephrine results in decreased numbers of viable bacteria in tissue and a lower incidence of wound infection in this model.

Aggressive approach to the extremity damaged by electric current

Electrical current injuries involving the extremities occurred in 41 of 75 patients with electrical burns admitted to the Oregon Burn Center over an 11 year period. Based solely on physical findings, the muscle compartments of 27 limbs in 14 patients were promptly explored, decompressed, and debrided of necrotic tissue on admission. This resulted in the salvage of 10 useful extremities. Major amputation of 11 extremities was carried out during initial surgery. No extremity needing exploration was overlooked. After exploration and fasciotomy, exposed tissues were protected with biologic dressings until repeated explorations and debridements demonstrated the absence of necrotic tissues and closure could be accomplished. The use of both local and free flaps was helpful in closing the wounds. No evidence or renal failure and no deaths attributable to retained necrotic tissue occurred.

Biostereometrics and computergraphics for patients with craniofacial malformations: diagnosis and treatment planning

Utilizing the techniques of biostereometric photography and current state-of-the-art computergraphics, topographic contourgrams have been generated in a series of patients with complex craniofacial malformations. These contourgrams are considered useful in diagnosis and treatment planning and as an aid in postoperative follow-up. We hope that the technique will provide a means to study longitudinal growth in unoperated and operated patients with craniofacial malformations. Comparisons between these groups and normal patients are currently being investigated.

Denaturation behavior of antithrombin in guanidinium chloride. Irreversibility of unfolding caused by aggregation

The structural stability of the protease inhibitor antithrombin from bovine plasma was examined as a function of the concentration of guanidinium chloride (GdmCl). A biphasic unfolding curve at pH 7.4, with midpoints for the two phases at 0.8 and 2.8 M GdmCl, was measured by far-ultraviolet circular dichroism. Spectroscopic and hydrodynamic analyses suggest that the intermediate state which exists at 1.5 M GdmCl involves a partial unfolding of the antithrombin molecule that exposes regions of the polypeptide chain through which slow, intermolecular association subsequently takes place. The partially unfolded molecule can be reversed to its fully functional state only before the aggregation occurs. Upon return of the aggregated state to dilute buffer, the partially unfolded antithrombin remains aggregated and does not regain the spectroscopic properties, thrombin-inhibitory activity, or heparin affinity of the native inhibitor. This behavior indicates that the loss of the functional properties of the proteins is caused by the macromolecular association. Comparative experiments gave similar results for the human inhibitor. Analyses of bovine antithrombin in 6 M GdmCl indicated that the second transition reflects the total unfolding of the protein to a disulfide-cross-linked random coil. This transition is spectroscopically reversible; however, on further reversal to dilute buffer, the molecules apparently are trapped in the partially unfolded, aggregated, intermediate state. The results are consistent with the existence of two separate domains in antithrombin which unfold at different concentrations of GdmCl but do not support the contention that the thrombin-binding and heparin-binding regions of the protein are located in different domains [Villanueva, G. B., & Allen, N. (1983) J. Biol. Chem. 258, 14048-14053].

Management of mandibular fractures in unreliable patient populations

There is a high incidence of complications following treatment of fractures of the dentulous mandible at our institution, which has led us to scrutinize the criteria for maintaining teeth in the line of fracture and to evaluate other factors that may compromise healing of the fractured mandible, especially in an unreliable patient population. We have reviewed the opinions of various authors and agree that management decisions must be individualized. We recommend prompt and stable immobilization, adequate observation, use of a "tickle file" to keep track of missed appointments, and long-acting intramuscular prophylactic antibiotic coverage, all of which will help minimize morbidity associated with teeth in the line of mandibular fractures, especially in high-risk patients. We also recommend extraction of fully or partially erupted third molars in the line of fracture as well as deeply carious teeth, severely mobile teeth, or teeth with half or more of their root surface exposed to the fracture line. Finally, we recommend that intraoral rather than extraoral open reduction be considered when teeth are to be extracted in order to avoid contamination with the extraoral environment, to enhance surgical access, and to lower postsurgical morbidity.

Complications of embolization treatment for problem cavernous hemangiomas

Radiologists trained in selective angiography can now deliver sclerosing or occluding materials to the arterial supply of vascular tumors. Such skills require special training and there are limitations to the use of these materials. Specific obliteration can be carried out if this technique is quality controlled. Materials being used for embolization are continually being studied and are changing as new materials are developed. Radiologists can assist surgeons in managing some of these very difficult problems. A large series of patients with various vascular lesions treated at the Oregon Health Sciences University was reviewed. The complications of embolization used for cavernous hemangiomas have tempered our enthusiasm for it as an adjunct form of therapy. We do feel that this method of treatment remains useful in selected cases. The occlusion achieved caused a decrease in both symptoms and size of lesions treated. The decrease in size excluded the need for surgery in 3 cases, aided resection in 1, but caused significant complicating slough in 1. Five cases are presented to demonstrate problems of tissue necrosis encountered.

Inadvertent intraradial arterial injection of cocaine

Injection of a chemical irritant into the radial artery at the wrist causes acute discoloration of the skin, edema, and pain in the hand. Subsequent damage due to vasospasm, endarteritis, particulate embolization, and vascular thrombosis may result in ischemic contractures, amputations, and other functional hand deficits. Injection of a street cocaine preparation into the radial artery of a 22-year-old man produced a constellation of signs and symptoms similar to that described for other irritants. Current thoughts with regard to the pathophysiology and treatment of these injuries are reviewed.