Late salvage of a free TRAM flap

We present the case of a patient with arterial thrombosis of a free TRAM flap 11 days after surgery. Initial salvage involved thrombectomy through an arteriotomy using a Fogarty catheter. Subsequent return to the operating theatre was necessary because of further vascular compromise. Thrombectomy was combined with flap thrombolysis and anticoagulation, and the flap remained viable at 6 months. Although rates of successful salvage vary, the literature indicates that flaps are rarely saved if signs of compromise present later than 2 days postoperatively. This case demonstrates that aggressive salvage may be successful even in cases of 'late' vascular compromise.

Evidence for superantigen involvement in severe group a streptococcal tissue infections

Host-pathogen interactions were studied in tissue biopsy samples from patients with severe invasive group A streptococcus (GAS) infections. Skin, subcutaneous tissue, and fascia biopsy samples were divided into clinical grade 1 (no evidence of inflammation [n=7]) or clinical grade 2 (inflamed tissue--erythema and edema including cellulitis, fasciitis, and necrotizing fasciitis [n=24]). In situ imaging demonstrated significantly higher bacterial load in biopsy samples of higher clinical grade (P<.05), and the bacterial load correlated with the in vivo expression of the superantigen streptococcal pyrogenic exotoxin F (P<.02). Increased expression of the interleukin-1 cytokines and significantly higher expression of tumor necrosis factor-beta, interferon-gamma, and the homing receptors CC chemokine receptor 5, CD44, and cutaneous lymphocyte-associated antigen (P<.002-.05) were observed in biopsy samples of higher clinical grade. Thus, the cytokine profile at the local site of infection mimics that of a typical superantigen cytokine response. The findings of this study demonstrate a critical role for superantigens and Th1 cytokines in GAS tissue infections.

Can bacterial interference prevent infection?

The concept that one bacterial species can interfere with the ability of another to colonize and infect the host has at its foundation the prerequisite that bacteria must attach to biological surfaces to cause infection. Although this is an over-simplification of pathogenesis, it has led to studies aimed at creating vaccines that block adhesion events. Arguably, the use of commensal bacteria (also referred to as "normal flora", "indigenous" or "autochthonous" microorganisms) to inhibit pathogens has even greater potential than vaccine use, because these bacteria are natural competitors of pathogens and their action does not require host immune stimulation. Exogenous application of commensal organisms (probiotics) has been shown to reduce the risk of infections in the gut, urogenital tract and wound sites. To manipulate and optimize these effects, further studies are required to understand cell signaling amongst commensals and pathogens within biofilms adherent to host tissues. The potential for new therapeutic regimens using probiotics is significant and worthy of further study.

Electrophysical properties of electrosurgery and capacitive induced current

BACKGROUND

Although electrosurgery is one of the most commonly used technologies in the operating room, its electrophysical properties, including the potential for complications, are poorly understood by many surgeons.

METHODS

We describe the experimental simulation of a highly unusual complication that occurred during a surgical procedure requiring concurrent use of monopolar and bipolar electrosurgery.

RESULTS

Capacitive induced current from an activated monopolar electrode to the bipolar cord was reproduced and consistently led to full-thickness burns in our experiments.

CONCLUSIONS

Surgeons should be familiar with the principles of electrosurgery, its electrophysical properties, and possible complications.

Identification of collagen-binding proteins in Lactobacillus spp. with surface-enhanced laser desorption/ionization-time of flight ProteinChip technology

Biosurfactants produced by Lactobacillus fermentum RC-14, L. rhamnosus GR-1 and 36, and L. casei Shirota were found to contain proteins that bind to both collagen types III and VI, as determined by surface-enhanced laser desorption/ionization (SELDI)-time of flight mass spectrometry. Both collagen types III and VI immobilized on SELDI preactivated ProteinChip arrays detected several different sizes (2 to 48 kDa) of collagen-binding proteins. Overall, the RC-14-produced biosurfactant contained the greatest number of collagen-binding proteins (RC-14 > GR-1 > 36 > Shirota), including the mature form of a previously cloned 29-kDa collagen-binding protein (referred to in its mature 26-kDa form). Although biosurfactants isolated from L. casei Shirota and L. rhamnosus 36 and GR-1 also contain several collagen-binding proteins, they do not contain the 26-kDa collagen-binding protein. Together, these results demonstrate the utility of the SELDI system as a means of rapidly characterizing clinically important but complex biosurfactant solutions.

Infected nonunion of the tibia

The treatment of infected nonunited fractures of the tibia using the techniques of Ilizarov was compared with autogenous cancellous bone graft application under a well vascularized soft tissue envelope. There were 10 patients in the Ilizarov group and 17 in the bone graft group. Soft tissue coverage with a free vascularized or a rotational muscle flap was used more frequently among the patients having bone graft (71%) than the Ilizarov group (30%). All 27 patients had bony defects (average, 3.7 cm; range, 1-18 cm). At an average followup of 6 years, 26 patients had a functional limb, and one patient (Ilizarov group) ultimately required a below knee amputation. Three patients in each group required a second plate and bone graft procedure to gain union. Infection persisted in four patients (all in the Ilizarov group). If a well vascularized soft tissue envelope is present (particularly after flap coverage), bone grafting procedures are safe and efficacious. The Ilizarov technique may be best suited for the treatment of very proximal or distal metaphyseal nonunions and nonunions associated with large leg length discrepancies.

Calciphylaxis precipitated by ultraviolet light in a patient with end-stage renal disease secondary to systemic lupus erythematosus

Calciphylaxis is a rare and severe calcification syndrome described mainly in patients with end-stage renal disease (ESRD) undergoing dialysis or with a renal transplant. This life-threatening condition is characterized by the abrupt onset of painful ischemic skin ulcers and necrosis. Secondary local and systemic infection may supervene and, without timely and appropriate interventions, calciphylaxis may be fatal. A precipitant or challenging agent is believed to be necessary to initiate the process. We describe a case of a woman with ESRD receiving continuous ambulatory peritoneal dialysis who developed calciphylaxis in the setting of severe hyperparathyroidism after receiving UV photoradiation therapy. We suggest that the UV light served as the challenging agent in the precipitation of this devastating condition.

Loading pyranine via purinergic receptors or hypotonic stress for measurement of cytosolic pH by imaging

Although used extensively for the measurement of intracellular pH, derivatives of fluorescein such as 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) have suboptimal sensitivity and can generate toxic photoproducts. These limitations can be overcome using the pH-sensitive fluorescent dye 8-hydroxypyrene-1,3,6-trisulfonic acid (pyranine), which has improved spectroscopic properties. However, the use of pyranine has been limited by the difficulties encountered in delivering this highly hydrophilic dye to the cell interior. We describe a strategy for intracellular delivery of pyranine based on the reversible activation of purinergic P2x7 receptors, which allow permeation of the dye into otherwise intact cells. When loaded into J774 or RAW cells by this method, pyranine is not only more sensitive than BCECF (the dynamic range is approximately 7-fold greater), but is retained better and is less toxic. Pyranine was distributed throughout the cytosol but was not detectable in endomembrane compartments. Repeated illumination resulted in blebbing and loss of functional responsiveness of cells loaded with BCECF, whereas comparably irradiated cells loaded with pyranine remained healthy and responsive. Pyranine can also be loaded into cells not expressing P2x7 receptors by brief exposure to a hypotonic solution. The properties of cells labeled by this method are similar to those loaded via purinergic receptors and compare favorably with those of BCECF-loaded cells. Pyranine thus provides a useful alternative to fluorescein derivatives for the measurement of intracellular pH, particularly when using the high excitation intensities required for microscopic digital imaging.

Topological analysis of NHE1, the ubiquitous Na+/H+ exchanger using chymotryptic cleavage

Proteases, glycosidases, and impermeant biotin derivatives were used in combination with antibodies to analyze the subcellular distribution and transmembrane disposition of the Na+/H+ exchanger NHE1. Both native human NHE1 in platelets and epitope-tagged rat NHE1 transfected into antiport-deficient cells were used for these studies. The results indicated that 1) the entire population of exchangers is present on the surface membrane of unstimulated platelets, ruling out regulation by recruitment of internal stores of NHE1; 2) the putative extracellular loops near the NH2 terminus are exposed to the medium and contain all the N- and O-linked carbohydrates; 3) by contrast, the putative extracellular loops between transmembrane domains 9-10 and 11-12 are not readily accessible from the outside and may be folded within the protein, perhaps contributing to an aqueous ion transport pathway; 4) the extreme COOH terminus of the protein was found to be inaccessible to extracellular proteases, antibodies, and other impermeant reagents, consistent with a cytosolic localization; and 5) detachment of approximately 150 amino acids from the NH2-terminal end of the protein had little effect on the transport activity of NHE1.

Late digital replantation failure: pathophysiology and risk factors

It is generally accepted that replanted digits surviving at least 1 week following surgery rarely succumb to ischemic necrosis. Presented here are 2 patients who experienced late digital replantation failure. The first patient is an 8-year-old boy who had his index finger replanted at the proximal phalangeal level. After 16 days of viability, the replanted digit became swollen and subsequently necrosed. The second patient is a 35-year-old man with a history of smoking and intravenous drug use who underwent replantation of his avulsed thumb at the metacarpophalangeal joint. The replanted thumb was viable at the 2-week follow-up, but began to show ischemic changes at 3 weeks and eventually required revision amputation at the interphalangeal level. Both of these patients demonstrate late digital replantation failure--an unusual and poorly understood phenomenon. A discussion of possible risk factors and potential pathophysiology is presented.

Use of bilateral folded radial forearm free flaps for reconstruction of a midface gunshot wound

Optimal treatment of midfacial gunshot wounds includes early definitive reconstruction of the bony scaffold to prevent soft tissue contraction. When this is not possible, secondary reconstruction is more difficult. The authors present a case of delayed reconstruction of a midface gunshot wound. Two months following a self-inflicted, submental gunshot wound and eventual rigid fixation of the remaining midfacial bony anatomy, two simultaneous radial forearm free flaps were utilized in the reconstruction. The first flap was folded onto itself to recreate the hard palate in conjunction with a split rib graft; the second flap filled the remaining soft-tissue defect and simultaneously provided lining for an eventual staged nasal reconstruction. The second stage of the nasal reconstruction was completed 5 weeks later with a calvarial bone graft and forehead flap. This dual microsurgical approach allowed for one-step reconstruction of both surfaces of the hard palate, resulting in separate oral and nasal cavities, and optimizing the patient's ability to speak and eat. Extensive soft-tissue contraction encountered in late reconstructions underscores the importance of an early, definitive, surgical approach in these difficult wounds.

Soft tissue management of open tibia fractures

In this article, we have outlined our treatment approach to severe open tibial fractures (Gustilo type III injuries). We believe that collaboration between the plastic surgeons and orthopedic surgeons will aid in minimizing complications and facilitate optimal rehabilitation. In our opinion, the treatment of these injuries is facilitated in trauma centers with the expertise to address the complicated issues surrounding bone and soft tissue management techniques. The fundamental concepts of our approach are adequate debridement and early bone fixation, followed by soft tissue closure with obliteration of all dead space. Bone defects are addressed 4 to 8 weeks following injury with cancellous bone grafts or vascularized fibula transfer. This protocol has been successful in virtually eliminating the problem of infection and in salvaging and rehabilitating severely injured extremities.

The effects of ultrasound treatment on flexor tendon healing in the chicken limb

We report the effects of early and late ultrasound treatment protocols on healing of surgically lacerated zone 2 flexor tendons in a chicken model. Ultrasound was administered directly using a coupling gel. Treatment was shown to increase range of movement, to advance scar maturation and to decrease the amount of inflammatory infiltrate around the repair site. No adverse effects on tensile strength were noted in either group. Early (starting 7 days post-operatively) administration was more effective than late (starting 42 days post-operatively) administration in achieving these effects. These results suggest that ultrasound therapy may be of benefit in the early healing process of flexor tendon lacerations.

Arthroscopic treatment of triangular fibrocartilage tears

Lesions of the TFCC are more frequently implicated as a cause of ulnar-sided wrist pain. Accurate diagnosis of TFCC pathology must be based on a thorough history and physical examination. Imaging modalities of particular use include plain radiographs, triple compartment arthrography, and MR imaging. The most sensitive and accurate diagnosis of the extent as well as the clinical significance of intra-articular pathology on the ulnar side of the wrist is by means of the arthroscope. With the advent of smaller and more elaborate arthroscopic instrumentation, the ability to perform arthroscopic surgery on the TFCC has dramatically increased over the past decade. The present arthroscopic treatment of traumatic central and radial lesions consists of debridement of unstable flaps, whereas dorsal and ulnar-sided lesions can be directly repaired. Centrally located degenerative perforations can be debrided in conjunction with an arthroscopic wafer procedure on the distal ulna.

Intralesional methotrexate in keratoacanthoma of the nose

Keratoacanthomas are rapidly growing benign cutaneous neoplasms, usually occurring on sun-exposed areas of the body. Although many treatment modalities have been described, surgical excision is currently the treatment of choice for the majority of keratoacanthomas. Occasionally, however, the size and location of these lesions preclude complete excision without extensive reconstruction and/or scarring. Two such cases of large keratoacanthoma of the nose were treated successfully with intralesional methotrexate. The rapid regression and very acceptable final cosmetic result suggest that intralesional methotrexate may play a beneficial role in the treatment of these difficult lesions and encourage further study of the benefits of this treatment modality.

An unusual complication of appendectomy

Intraabdominal abscess formation is a well-recognized complication of perforated appendicitis. Extraabdominal complications, however, are rare. The authors present the case of an 8-year-old boy who had an acute painful right-sided scrotal mass 2 days after an operation for perforated appendicitis. During exploration, an abscess within a previously undiagnosed patent processus vaginalis was found and successfully managed by drainage. This case demonstrates that a persistent patent processus vaginalis may predispose to scrotal pathology secondary to intraabdominal sepsis and represents a unique complication of perforated appendicitis.

Distinct coronary artery receptor systems for epidermal growth factor-urogastrone

In porcine (PCA) and bovine (BCA) coronary arterial strips, epidermal growth factor-urogastrone (EGF-URO) caused an endothelium-independent Ca-requiring contractile response that could not be attributed to the secondary release of agonists from neural elements. In these tissues, EGF-URO also potentiated the contractile actions of other agonists (prostaglandin F2 alpha, KCl or norepinephrine). Nonetheless, the responsiveness of the PCA and BCA preparations differed markedly in terms of 1) their sensitivity to indomethacin and dexamethasone (indomethacin and dexamethasone abrogated the PCA but not the BCA response), 2) their desensitization properties (the BCA rapidly desensitized, whereas the PCA did not) and 3) the order of potencies for EGF-URO and transforming growth factor-alpha (TGF-alpha) (in the PCA, EGF-URO was more potent than TGF-alpha, whereas in the BCA, the potency of TGF-alpha was greater than or equal to that of EGF-URO). Taken together our data document the presence of two distinct receptor signaling systems for EGF-URO in the PCA and BCA preparations, and our results support the hypothesis that distinct receptor subtypes for EGF-URO may be present in these two tissues.

Autoradiographic localization of binding sites for epidermal growth factor-urogastrone (EGF-URO) in coronary arteries

Previously published data have indicated that epidermal growth factor-urogastrone (EGF-URO) can regulate blood flow in vivo and can modulate vascular smooth muscle contractility in vitro. However, the exact location of the receptors responsible for this vascular action of EGF-URO has not been previously determined. In this report, employing in vitro autoradiography with 125I-labeled EGF-URO, we have documented the presence of specific EGF-URO binding sites in the tunica media of bovine and porcine coronary arteries. Our observations support the indirect evidence pointing to presence of EGF-URO receptors on the smooth muscle elements of arterial tissue. Our data also support further the hypothesis that EGF-URO and related growth factors (like TGF-alpha or PDGF) may play a role in normal and pathophysiological vascular function.

Epidermal growth factor-urogastrone causes vasodilatation in the anesthetized dog

Epidermal growth factor-urogastrone (EGF-URO) administered intraarterially was a potent dilator in dog femoral (FEM), superior (cephalic) mesenteric (SMA), celiac (CAC), coronary (COR), carotid (CAR), and renal (REN) vascular beds. The effects of EGF-URO, which exhibited tachyphylaxis, could not be attributed either to recirculating EGF-URO or to the secondary release of other agonists or products of the cyclooxygenase pathway. Two vascular beds (FEM, SMA) showed a high maximum responsiveness to EGF-URO (maximum effect [Emax] approximately equal to 70% increase in flow) whereas another group (CAC, COR, CAR, and REN) exhibited lower responsiveness (Emax approximately equal to 20%). The ED50 for this effect of EGF-URO was in the range of 0.4 micrograms (FEM, SMA, CAR, and COR) to 0.9 micrograms (CAC and REN). In isolated dog COR helical strips, EGF-URO did not exhibit either a direct relaxing or a contractile effect. However, preincubation of strips with EGF-URO caused up to a 66% inhibition of contraction in response to norepinephrine (1 microM), with an ED50 for EGF-URO of 1 nM. This action of EGF-URO also showed marked tachyphylaxis. Our data point to a potential role for EGF-URO (and possibly for the structurally related alpha-transforming growth factor) in the regulation of blood flow in vivo.

Distinct vascular actions of epidermal growth factor-urogastrone and transforming growth factor-alpha

We compared the effects of epidermal growth factor-urogastrone (EGF-URO) with those of transforming growth factor-alpha (TGF-alpha) on regional blood flow in the anesthetized dog in vivo, and on isolated canine helical coronary artery strips in vitro. Like EGF-URO, TGF-alpha was a potent stimulator of femoral arterial blood flow in vivo; and, when added to the tissue bath in vitro before an agonist, TGF-alpha like EGF-URO was a potent inhibitor of the contractile responses of helical coronary arterial strips to various smooth muscle agonists: norepinephrine (NE), prostaglandin F2 alpha (PGF alpha) and potassium chloride (KCl). Nonetheless, there were marked differences between EGF-URO and TGF-alpha in terms of the two biological responses measured. In terms of blood flow, although the ED50 for the increase in blood flow was similar for EGF-URO and TGF-alpha (ED50 = 0.4 micrograms EGF-URO equivalents per dose), the maximum responsiveness to TGF-alpha (130% increase in flow) was substantially greater than the maximum response to EGF-URO (70% increase in flow). Furthermore, TGF-alpha did not cause tachyphylaxis to subsequent doses of TGF-alpha, whereas a prior dose of either EGF-URO or TGF-alpha desensitized markedly the blood flow preparations to EGF-URO. Different desensitization patterns for the actions of EGF-URO and TGF-alpha also were observed in the arterial strip preparations. The inhibitory action of EGF-URO for agonist (NE, PGF2 alpha or KCl)-mediated contraction was diminished with repeated exposure of the tissue to EGF-URO, whereas the inhibitory action of TGF-alpha persisted with repetitive tissue exposure.(ABSTRACT TRUNCATED AT 250 WORDS)