Kenneth J. Woodside

Morphologic characteristics of varicose veins: possible role of metalloproteinases☆

BACKGROUND Although varicose veins are a common cause of morbidity, etiologic factors predisposing to dilatation, elongation, and tortuosity of the saphenous vein and its tributaries are poorly understood. We compared histologic features of normal and varicose saphenous veins and investigated the role of enzyme or inhibitor imbalance in development of varicosities. METHODS Eight normal and 10 varicose (C(2,3)E(P,S)A(S)P(R,O)) vein segments were used for this analysis. Matrix metalloproteinase (MMP) expression and activity were analyzed with Western blotting and zymography. Venous architecture and protein localization were determined with histology and immunohistochemistry. RESULTS Western blot analysis demonstrated the presence of MMP- 1, MMP-2, MMP-9, and MMP-12, as well as small quantities of tissue inhibitor of metalloproteinases (TIMP)-1 and TIMP-2 in protein isolates from normal and varicose veins. Both vein types demonstrated MMP-2, MMP-9, and MMP-12 activity by gelatin zymography, although varicose vein expressed less MMP-9 activity than normal vein did. Compared with normal veins, changes in varicose veins were not uniformly distributed along the circumference; areas of intimal thickening were often interspersed with focal areas of dilatation. Fragmentation of elastic lamellae and loss of circular and longitudinal muscle fibers were evident in the varicosities. Focal aggregates of macrophages were detected within the media and adventitia of both normal and varicose veins. MMP-1 and MMP-9 were expressed in both types of vein segments; however, their immunohistochemical localization was distinctly different. In normal vein, endothelial cells, occasional smooth muscle cells (SMC), and adventitial microvessels expressed MMP-1, whereas its expression was localized to fibroblasts, SMC, and endothelial cells throughout involved portions of varicose veins. MMP-9 was localized to endothelial cells, medial SMC, and adventitial microvessels in both normal and varicose veins, although varicose veins demonstrated increased medial smooth muscle cell staining. MMP-12 was found in SMC and fibroblasts in both normal and varicose veins. Neither TIMP-1 nor TIMP-2 were detected with immunohistochemistry in any specimens examined. CONCLUSIONS There are distinct differences in the structural architecture and localization of MMP expression in normal and varicose veins. Although the changes observed are not sufficiently definitive to enable a causal relationship, they do suggest a possible mechanism for the alterations in matrix composition observed between normal and varicose veins.

Deep venous thrombosis prophylaxis in trauma: improved compliance with a novel miniaturized pneumatic compression device

OBJECTIVE Intermittent pneumatic compression (IPC) devices prevent lower-extremity deep venous thrombosis (LEDVT) when used properly, but compliance remains an issue. Devices are frequently discontinued when patients are out of bed, and they are rarely used in emergency departments. Trauma patients are at high risk for LEDVT; however, IPCs are underused in this population because of compliance limitations. The hypothesis of this study was that a new miniaturized, portable, battery-powered pneumatic compression device improves compliance in trauma patients over that provided by a standard device. METHODS This was a prospective trial in which trauma patients (mean age, 46 years; revised trauma score, 11.7) were randomized to DVT prophylaxis with a standard calf-length sequential IPC device (SCD group) or a miniaturized sequential device (continuous enhanced-circulation therapy [CECT] group). The CECT device can be battery-operated for up to 6 hours and worn during ambulation. Timers attached to the devices, which recorded the time each device was applied to the legs and functioning, were used to quantify compliance. For each subject in each location during hospitalization, compliance rates were determined by dividing the number of minutes the device was functioning by the total minutes in that location. Compliance rates for all subjects were averaged in each location: emergency department, operating room, intensive care unit, and nursing ward. RESULTS Total compliance rate in the CECT group was significantly higher than in the SCD group (77.7% vs. 58.9%, P =.004). Compliance in the emergency department and nursing ward were also significantly greater with the CECT device (P =.002 and P =.008 respectively). CONCLUSIONS Previous studies have demonstrated that reduced compliance with IPC devices results in a higher incidence of LEDVT. Given its ability to improve compliance, the CECT may provide superior DVT prevention compared with that provided by standard devices.

Current management of gastrointestinal carcinoid tumors

Gastrointestinal carcinoid tumors are rare neuroendocrine tumors arising from the embryologic primitive gut. Depending on the location in the gastrointestinal tract, these tumors may secrete a variety of hormonally active substances. However, many of these tumors are found incidentally, or the diagnosis is made postoperatively. Also, there is a significant incidence of multicentric carcinoid tumors and synchronous noncarcinoid malignancies in these patients. Treatment is usually based on the size of the tumor. Surgical resection remains the cornerstone of therapy. For advanced metastatic disease, somatostatin analog therapy and surgical debulking provide the best symptomatic relief and may improve survival. Recent studies have demonstrated a benefit from radiolabeled somatostatin analogs for carcinoid tumor localization. In contrast, radiolabeled somatostatin analogs have shown little therapeutic benefit. Future directions include somatostatin receptor profiling of carcinoid tumors, with somatostatin analog therapy targeting the specific receptors.

Predictors of alveolar air leaks.

Persistent air leaks are caused by the failure of the postoperative lung to achieve a configuration that is physiologically amenable to healing. The raw pulmonary surface caused by the dissection of the fissure often is separated from the pleura, and the air leak fails to close. Additionally, higher air flow thorough an alveolar-pleural fistula seems to keep the fistula open. Other factors that interfere with wound healing, such as steroid use, diabetes, or malnutrition, can result in persistence of the leak. A thoracic surgeon can minimize the incidence of air leak through meticulous surgical technique and can identify patients in whom the balance of risks (Table 1) and benefits warrant operative intervention based on an understanding of the underlying pathophysiology.

Safe administration of a humanized murine antibody after anaphylaxis to a chimeric murine antibody.

Background. Basiliximab and daclizumab are potent and relatively safe immunosuppressive induction agents used in transplantation. These chimeric or humanized monoclonal antibodies, respectively, act by binding to the &agr; chain of interleukin-2 receptors on activated T lymphocytes. Herein, the authors describe successful transplant induction therapy with a humanized murine antibody in a patient with a history of anaphylaxis to a chimeric murine antibody. Methods. The authors report a 42-year-old woman who received a dose of basiliximab without adverse reaction before an anticipated renal transplant that was canceled. Two weeks later, she received a second dose of basiliximab. Within 10 min of receiving the second dose, she developed chest tightness, shortness of breath, tongue swelling, diffuse pruritic rash, and skin flushing. Results. The authors hypothesized that her anaphylaxis was mediated by immunoglobulin (Ig) E antibodies to basiliximab. Consistent with this hypothesis, intradermal administration of a 1:100 dilution of basiliximab induced a 10 × 10-mm flare. The authors sought to find an alternative immunosuppressive agent for this patient. The patient elicited prick and intradermal skin testing responses to horse and rabbit polyclonal antithymocyte antibody preparations. However, she mounted neither a prick nor an intradermal response to daclizumab. The patient was administered daclizumab without any adverse effects. Conclusions. The negative skin test and safe administration of daclizumab is surprising because the similarity of these hybrid antibodies would have predicted similar IgE responsiveness and clinical outcome. The authors propose that patients who develop anaphylaxis to basiliximab or other chimeric antibodies may be candidates for treatment with a humanized antibody preparation such as daclizumab in the presence of a negative skin test to the humanized agent.

Disseminated Pseudallescheria boydii (Scedosporium apiospermum) infection in a renal transplant patient.

Abstract: Transplant recipients receive a number of immunosuppressive medications that result in an increased risk of infection, including infections with microbes that are normally not pathogenic. We describe a patient with end‐stage renal disease who underwent kidney transplantation. Six months postoperatively, he presented with a lesion on his ankle, multiple thigh nodules, and right testicular pain. Biopsy of the ankle lesion demonstrated Pseudallescheria boydii (Scedosporium apiospermum), a common environmental fungus. Following orchiectomy, multiple fungal elements were found that were initially described as Aspergillus species, but later identified as P. boydii. In addition, multiple brain abscesses were found on magnetic resonance imaging. Despite treatment with multiple antifungal medications, the patient died of cardiac dysrhythmia. Current diagnostic and therapeutic alternatives for P. boydii are reviewed.

Differential effects of interleukin-2 blockade on apoptosis in naïve and activated human lymphocytes

Background. Certain transplantation immunosuppressive strategies are primarily based on the interruption of interleukin (IL)-2 signaling by calcineurin inhibition or anti-IL-2 receptor-antibody blockade. However, recent evidence suggests that IL-2 is necessary for peripheral deletion of allograft-specific lymphocytes. Study Design. In this study, we examined the apoptotic effects of the calcineurin inhibitor, cyclosporine A, the chimeric anti-interleukin-2 receptor monoclonal antibody, basiliximab, and the rabbit antihuman thymocyte preparation Thymoglobulin (rATG) on phytohemagglutinin-activated human lymphocyte models designed to simulate initial exposure to the graft or ongoing rejection of the graft. Results. We found that rATG increases Fas expression, decreases Bcl-2 expression, and induces early apoptosis in naïve lymphocytes. However, rATG has more of a necrotic effect on activated lymphocytes. Basiliximab and cyclosporine had little effect on apoptosis, but did alter Bcl-2 and Fas expression. Conclusions. Compared with IL-2 pathway inhibitors, rATG increases lymphocyte apoptosis, probably via Bcl-2 pathway inhibition. Because apoptosis is required for the development of graft tolerance, induction strategies that use IL–2-independent pathways may be advantageous.

Use of kidneys from hepatitis C seropositive donors shortens waitlist time but does not alter one‐yr outcome*

Utilization of hepatitis C seropositive kidney donors remains controversial. We examined the use of hepatitis C seropositive donors for renal transplantation. Data for creatinine, liver function tests, cold ischemia time, and graft and patient survival were analyzed from 20 hepatitis C seropositive recipients receiving cadaveric renal allografts from seropositive donors and were compared with 20 hepatitis C seropositive recipients receiving allografts from seronegative donors. Recipients receiving a kidney from a hepatitis C seropositive donor were on the waitlist for 9.9 ± 1.8 months, compared with 17.8 ± 3.3 months for those receiving a kidney from a seronegative donor (p < 0.05). There were no significant differences in graft or patient survival. Incidences of acute cellular rejection and acute tubular necrosis were similar. There were no significant differences in creatinine, alanine aminotransferase, alkaline phosphatase, or bilirubin values. While there was a significant difference in aspartate aminotransferase at 2 wk and 6 months, these differences were of questionable clinical importance. In conclusion, donor seropositivity for hepatitis C should not preclude renal transplantation into a hepatitis C seropositive recipient and utilization of these organs decreases waitlist time for hepatitis C seropositive recipients.

Differential gene expression in primary and recurrent carotid stenosis

Apoptosis of the cellular components of complex atherosclerotic plaque may lead to plaque instability and rupture. In this study, five primary plaques and one recurrent fibrointimal lesion obtained from patients undergoing carotid endarterectomy for symptomatic carotid stenosis > or = 70% were analyzed by immunohistochemistry and cDNA microarray to identify gene expression patterns that may determine plaque susceptibility or resistance to apoptosis. Immunohistochemistry showed expression of active caspase 3, an effector of apoptosis, in macrophages and lymphocytes surrounding the lipid core, in smooth muscle cells in the fibrous cap, and media of primary plaques as well as in occasional smooth muscle cells in the recurrent lesion. Among the genes demonstrating increased expression in primary plaques were IGFR2, DR4, DAPK1, Bak, and ERK 1 and 2 and those showing decreased expression included the TNF receptors 1 and 2, akt1, and IGFBP3. When comparing the recurrent lesion to the normal tissue, the expression of 13 genes was decreased by 3-fold, including IGFBP2 and IGFBP3, and none were increased by more than 1.5-fold. The analysis of gene expression patterns in primary and recurrent stenotic lesions provides a powerful approach to identify the signaling pathways that alter cellular apoptotic patterns in such lesions.

Insulin-like growth factor-I/insulin-like growth factor binding protein-3 alters lymphocyte responsiveness following severe burn

PURPOSE Following severe burn, patients are immunocompromised, making them at increased risk for infection. Exogenous growth hormone has been shown to partially restore immune function. Herein, we investigated Th1/Th2 cytokine profiles and cellular proliferation in isolated mononuclear cells after treatment with exogenous insulin-like growth factor-I (IGF-I), the indirect mediator of many growth hormone effects, in severely burned patients. METHODS Eight children and 2 adults with >20% total body surface area burns were prospectively randomized to receive either placebo or 4 mg/kg rhIGF-I/IGFBP-3 for one-week intervals (2 groups), with another group receiving placebo for both cycles. Normal children were examined for comparison. Isolated whole blood lymphocyte production of Th1 (IL-2, IFN-gamma) and Th2 (IL-4, IL-10) cytokines, and proliferative responses to specific T-cell mitogens were measured. RESULTS Depressed Th1 and exaggerated Th2 cytokine responses were seen in all burned subjects compared to non-burned controls (P < 0.05). IL-2 and IFN-gamma production increased in patients treated with IGF-I/IGFBP-3 (P < 0.05). IL-4 production significantly decreased, while IL-10 levels did not change. Cytokine production did not change in those receiving two courses of placebo. Proliferative responses of isolated mononuclear cells to IL-2 as a Th1 specific mitogen increased with IGF-I/IGFBP-3 treatment (P < 0.05). CONCLUSIONS Following severe burn, a shift occurs toward a predominant Th2 phenotype. Exogenous IGF-I/IGFBP-3 treatment partially reverses this response.