Laparoscopic esophagectomy

Minimally invasive esophagectomy is emerging as an alternative option to open esophagectomy for benign and malignant esophageal diseases. This article provides a detailed review of the history of minimally invasive esophagectomy and an update on the currently accepted techniques for minimally invasive esophagectomy and its outcomes.

Clinical trial results with linezolid, an oxazolidinone, in the treatment of soft tissue and postoperative gram-positive infections

BACKGROUND

Infectious complications encountered after major surgery include operative site infections and nosocomial pneumonia. Recent infection surveillance programs have identified the increasing pathogenic role of gram-positive bacteria in these infections and the high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the United States and abroad. Surgical site infections and nosocomial pneumonia, often serious infections, are associated with adverse clinical outcomes including bacteremia and its resultant complications, as well as the socioeconomic consequences of excess hospitalization and discharge to nursing care.

METHODS

The essential triad for management of postoperative soft tissue infection consists of thorough appraisal of the infection site for reintervention, culture of drainage or infected tissue, and prompt initiation of empiric antimicrobial therapy designed to cover the most probable causative pathogens. Broad-spectrum antimicrobial regimens are often necessary for empiric therapy of skin and soft tissue infections or nosocomial pneumonia; however, regimens should be tailored to the most effective and clinically appropriate agent based on results of susceptibility testing.

RESULTS

Results of the clinical trial experience with the first United States Food and Drug Administration (FDA)-approved antimicrobial in the new class of oxazolidinones, linezolid, are reviewed.

CONCLUSION

In randomized, controlled trials, linezolid 600 mg twice daily (intravenously or orally) provided effective antimicrobial therapy for gram-positive soft tissue infections, including MRSA, and nosocomial pneumonia in which S. aureus was a causative pathogen.

Active stiffness of the ankle in response to inertial and elastic loads

Effective stiffness of the musculoskeletal system was examined as a function of the characteristics of an external load. Thirteen healthy subjects provided active contraction of the ankle plantarflexion musculature in a neutral ankle posture to support an external load. Musculoskeletal stiffness was computed from kinetic data recorded in response to dorsiflexion/plantarflexion perturbations. Ankle dynamics were recorded while supporting external loads of 19 and 38 kg with and without antagonistic co-contraction. External loads were applied using pure gravitational mass. In separate trials external loads were applied from stretch of steel springs in parallel with the plantarflexion musculature that also provided added parallel stiffness to the system. Adding external stiffness of 4.9 and 8.1 kN/m surprisingly failed to significantly change the stiffness of the ankle-plus-spring system. This suggests contributions from intrinsic muscle stiffness and reflex stiffness declined in response to added external stiffness. This could not be explained by load magnitudes, ankle postures, or co-activation as these were similar between the inertial and elastic loading conditions. However, non-linear parametric analyses suggest mean intrinsic stiffness of 35.5 kN/m and reflex gain of 11.6 kN/m with a constant reflex delay of 70 ms accurately described the empirical results. The phase response between the mechanical dynamics of the musculoskeletal system and delayed neuromotor feedback combine to provide robust control of system behavior.

Phase I studies of interleukin (IL)-2 and rituximab in B-cell non-hodgkin's lymphoma: IL-2 mediated natural killer cell expansion correlations with clinical response

PURPOSE

Expansion and activation of natural killer (NK) cells with interleukin-2 (IL-2) may enhance antibody-dependent cellular cytotoxicity (ADCC), an important mechanism of rituximab activity. Two parallel Phase I studies evaluated combination therapy with rituximab and IL-2 in relapsed or refractory B-cell non-Hodgkin's lymphoma (NHL).

EXPERIMENTAL DESIGN

Thirty-four patients with advanced NHL received rituximab (375 mg/m(2) i.v. weekly, weeks 1-4) and escalating doses of s.c. IL-2 [2-7.5 MIU daily (n = 19) or 4.5-14 million international units three times weekly (n = 15), weeks 2-5]. Safety, tolerability, clinical responses, NK cell counts, and ADCC activity were evaluated.

RESULTS

Maximally tolerated doses (MTD) of IL-2 were 6 MIU daily and 14 million international units thrice weekly. The most common adverse events were fever, chills, and injection site reactions. Dose-limiting toxicities were fatigue and reversible liver enzyme test elevations. Of the 9 patients enrolled at the daily schedule MTD, 5 showed clinical response. On the thrice-weekly schedule at the MTD, 4 of 5 patients responded. Responders showed median time to progression of 14.9 and 16.1 months, respectively, for the two studies. For the same total weekly dose, thrice-weekly IL-2 administration induced greater increases in NK cell counts than daily dosing, and NK cells correlated with clinical response on the thrice-weekly regimen. ADCC activity was increased and maintained after IL-2 therapy in responding and stable disease patients.

CONCLUSIONS

Addition of IL-2 to rituximab therapy is safe and, using thrice-weekly IL-2 dosing, results in NK cell expansion that correlates with response. This combination treatment regimen merits additional evaluation in a randomized clinical trial.

The role of beta-lactam antimicrobials as single agents in treatment of intra-abdominal infection

Broad-spectrum beta-lactam antibiotics have several advantages in the treatment of intra-abdominal infections. These agents are effective against gram-negative rods and anaerobes, reach therapeutic levels rapidly after parenteral administration, and, in the absence of penicillin allergy, generally exhibit low toxicity. The second-generation cephalosporins (e.g., cefoxitin, cefotetan) are used widely in surgical prophylaxis, trauma, and treatment of mild-to-moderate community-acquired infections, but limitations in their spectra and microbial resistance restrict their utility in more serious infections. Extended-spectrum penicillin/beta-lactamase-inhibitor combinations are effective in the treatment of intra-abdominal infections and include enterococci in their spectrum. Gram-negative aerobe resistance has developed to ampicillin/sulbactam. Piperacillin/tazobactam, a ureidopenicillin with increased gram-negative coverage and enhanced antipseudomonal activity, has proved to be effective in clinical trial therapy for intra-abdominal infections. The very broad spectrum carbapenems--imipenem/cilastatin and meropenem--are effective for serious infections or resistant organisms and are often used in the intensive care unit or for nosocomial intra-abdominal infection. These classes of beta-lactams comprise a range of antimicrobials that can be targeted effectively as single agents to both prevention and treatment of intra-abdominal infection.

New alternatives in management of the infected vascular prosthesis

BACKGROUND

Infection of vascular prosthetics implanted for arterial occlusive disease occurs in approximately 1-5% of patients, including early and late clinical presentation. The incidence of infection depends on the anatomical site, with the highest rate occurring in vascular access grafts placed for hemodialysis and in inguinal and lower extremity incisions in patients undergoing bypass procedures for femoropopliteal tibial occlusion. Treatment of prosthetic graft infection has traditionally included antimicrobials, excision of the infected prosthesis, and extraanatomical bypass. With the recognition that prosthetic infection secondary to Staphylococcus epidermidis can be managed with less extensive procedures, clinical data have been reported on in situ replacement with antibiotic-bonded prostheses. Patients who have S. aureus isolated, including methicillin-resistant S. aureus, or gram-negative pathogens, still require conventional graft excision and extraanatomical bypass.

METHODS

Selective review of the English-language literature.

RESULTS

Recent clinical series show that management by graft excision of infected infrarenal aortic prosthetics and axillofemoral bypass results in 2- and 5-year survival rates of 67% and 47%, and limb salvage rates in survivors of 93% and 82% at 2 and 5 years. In situ replacement with a rifampicin-bonded prosthesis has been accomplished successfully in smaller numbers of patients and shows promising early results. Other methods under study include cryopreserved arterial and femoral vein allografts and autogenous femoral vein grafts, but data are limited when used as replacement for infected prosthetics.

CONCLUSION

Advances in the management of infected vascular prostheses over the last decade have led to improved mortality and decreased amputation rates with conventional excision and extraanatomical bypass. Newer methods including in situ graft replacement with antibiotic-impregnated prosthetics appear suitable for low-virulence S. epidermidis infection. Early results are promising for cryopreserved allografts and autogenous femoral vein in situ grafts; however, more clinical experience and longer follow-up will be needed to confirm their durability in a contaminated field.

Eradication of multi-drug resistant Acinetobacter from an intensive care unit

BACKGROUND

Acinetobacter baumannii is a gram-negative coccobacillus that causes outbreaks of nosocomial infections in ICUs. Due to resistance to multiple antibiotics, management of clusters of A. baumannii is useful as a model in eradication of multi-drug resistant infections. We outline the evolution of an A. baumannii outbreak, focusing on methods of transmission and multidisciplinary measures aimed at eliminating it from the ICU.

METHODS

Patients in an urban, tertiary care medical center from November 1996 to December 1997 having positive cultures for multi-drug resistant A. baumannii are included in this study. A. baumannii was isolated on blood agar and MacConkey cultures and identified by Vitek panel. Disk diffusion including amikacin, imipenem, polymyxin B, and sulbactam were used to determine resistance.

RESULTS

An outbreak of 52 patients (27 infected, 25 colonized) with 68 positive sites began with the transfer of a colonized >50% total body surface area burn patient from an outside hospital. Within 3 days, the index patient was in the burn ICU, coronary care unit, and medical ICU. Soon, clusters of patients with A. baumannii infections sensitive only to polymyxin B were seen in those units and, ultimately, the surgical ICU. On typing, 2 strains were found, PFGE B and C. Given the level of antibiotic resistance, patients with colonization or infection were cohorted and placed on contact isolation. Strict antiseptic measures, such as hand-washing, barrier isolation, equipment and room cleaning, sterilization of ventilator equipment, and dedication of medical equipment to each patient were instituted. Still, positive environmental cultures were found in ventilator water traps, sinks, and bedrails. Sporadic cases continued for a total of 13 months, with 10 deaths resulting from the infections.

CONCLUSION

A. baumannii is a mildly virulent organism that becomes resistant to antimicrobials. Because of multiple antibiotic resistance, strict contact isolation cohorting and antiseptic technique are the primary modes of containment. This outbreak serves as a model of eradication of multi-drug resistant organisms from ICUs. These measures will become of greater importance as nosocomial organisms develop increasing resistance to antimicrobials.

Synergistic anti-tumor responses after administration of agonistic antibodies to CD40 and IL-2: coordination of dendritic and CD8+ cell responses

In cancer, the coordinate engagement of professional APC and Ag-specific cell-mediated effector cells may be vital for the induction of effective antitumor responses. We speculated that the enhanced differentiation and function of dendritic cells through CD40 engagement combined with IL-2 administration to stimulate T cell expansion would act coordinately to enhance the adaptive immune response against cancer. In mice bearing orthotopic metastatic renal cell carcinoma, only the combination of an agonist Ab to CD40 and IL-2, but neither agent administered alone, induced complete regression of metastatic tumor and specific immunity to subsequent rechallenge in the majority of treated mice. The combination of anti-CD40 and IL-2 resulted in significant increases in dendritic cell and CD8(+) T cell number in advanced tumor-bearing mice compared with either agent administered singly. The antitumor effects of anti-CD40 and IL-2 were found to be dependent on CD8(+) T cells, IFN-gamma, IL-12 p40, and Fas ligand. CD40 stimulation and IL-2 may therefore be of use to promote antitumor responses in advanced metastatic cancer.

Gender differences in active musculoskeletal stiffness. Part II. Quantification of leg stiffness during functional hopping tasks

Leg stiffness was compared between age-matched males and females during hopping at preferred and controlled frequencies. Stiffness was defined as the linear regression slope between the vertical center of mass (COM) displacement and ground-reaction forces recorded from a force plate during the stance phase of the hopping task. Results demonstrate that subjects modulated the vertical displacement of the COM during ground contact in relation to the square of hopping frequency. This supports the accuracy of the spring-mass oscillator as a representative model of hopping. It also maintained peak vertical ground-reaction load at approximately three times body weight. Leg stiffness values in males (33.9+/-8.7 kN/m) were significantly (p<0.01) greater than in females (26.3+/-6.5 kN/m) at each of three hopping frequencies, 3.0, 2.5 Hz, and a preferred hopping rate. In the spring-mass oscillator model leg stiffness and body mass are related to the frequency of motion. Thus male subjects necessarily recruited greater leg stiffness to drive their heavier body mass at the same frequency as the lighter female subjects during the controlled frequency trials. However, in the preferred hopping condition the stiffness was not constrained by the task because frequency was self-selected. Nonetheless, both male and female subjects hopped at statistically similar preferred frequencies (2.34+/-0.22 Hz), therefore, the females continued to demonstrate less leg stiffness. Recognizing the active muscle stiffness contributes to biomechanical stability as well as leg stiffness, these results may provide insight into the gender bias in risk of musculoskeletal knee injury.

Treatment of warfarin-associated coagulopathy: a physician survey

STUDY OBJECTIVES

(1) To determine physician preferences in the management of warfarin-induced excessive anticoagulation (AC); and (2) to assess compliance with the American College of Chest Physicians (ACCP) guidelines for the reversal of excessive AC.

DESIGN

Cross-sectional physician survey.

PARTICIPANTS

Members of the Canadian Society of Internal Medicine practicing in Ontario, Canada.

MEASUREMENTS AND RESULTS

Physicians were asked to provide management preferences in six clinical scenarios describing warfarin-induced excessive AC. The scenarios represent various combinations of international normalized ratio (INR) value, treatment setting, and presence and severity of bleeding. In scenarios with INRs < 5.2 without bleeding, conservative approaches complying with the ACCP guidelines, such as withholding warfarin or reducing its dose, were most common. In scenarios with high INRs (ie, > 7.1) and/or bleeding, the selection of vitamin K in any form ranged between 71% and 82%. However, compliance with the ACCP-recommended doses and the routes of vitamin K administration ranged from 1 to 10%. In five of the six scenarios, subcutaneous injection, a route not recommended by the ACCP, was the most common method of vitamin K delivery.

CONCLUSIONS

Physician preferences for the reversal of warfarin-induced excessive AC were highly variable and, in most cases, did not follow the recommendations of the ACCP consensus guidelines. Furthermore, the widespread reported use of subcutaneous vitamin K is concerning because this route of vitamin K administration has been demonstrated to be less effective than IV administration of vitamin K. These findings highlight the need for randomized controlled trials to compare the efficacy of different routes of administration of vitamin K for warfarin-associated coagulopathy.

The histone deacetylase inhibitor sodium butyrate induces DNA topoisomerase II alpha expression and confers hypersensitivity to etoposide in human leukemic cell lines

The differentiating agent and histone deacetylase inhibitor, sodium butyrate (NaB), was shown previously to cause a transient, 3-17-fold induction of human DNA topoisomerase II alpha (topo II alpha) gene promoter activity and a 2-fold increase in topo II alpha protein early in monocytic differentiation of HL-60 cells. This observation has now been extended to other short chain fatty acids and aromatic butyrate analogues, and evidence is presented that human topo II alpha promoter induction correlates closely with histone H4 acetylation status. Because increased topo II alpha expression is associated with enhanced efficacy of topo II-poisoning antitumor drugs such as etoposide, the hypothesis tested in this report was whether NaB pretreatment could sensitize HL-60 myeloid leukemia and K562 erythroleukemia cells to etoposide-triggered DNA damage and cell death. A 24-72 h NaB treatment (0.4-0.5 mM) induced topo II alpha 2-2.5-fold in both HL-60 and K562 cells and caused a dose-dependent enhancement of etoposidestimulated, protein-linked DNA complexes in both cell lines. At concentrations with minimal effects on cell cycle kinetics (0.4 mM in HL-60; 0.5 mM in K562), NaB pretreatment also modestly enhanced etoposidetriggered apoptosis in HL-60 cells, as determined morphologically after acridine orange/ethidium bromide staining, and substantially increased K562 growth inhibition and poly(ADP-ribose)polymerase cleavage after etoposide exposure. Therefore, a temporal window may exist whereby a differentiating agent may sensitize experimental leukemias to a cytotoxic antitumor agent. These results indicate that histone deacetylase inhibitors should be investigated for etoposide sensitization of other butyrate-responsive hematopoietic and nonhematopoietic tumor lines in vitro and in vivo.

Is intraoperative cholangiography during laparoscopic cholecystectomy cost effective?

BACKGROUND

Common bile duct injuries occur in 0.2% to 0.8% of laparoscopic cholecystectomies (LC). Intraoperative cholangiograms (IOCG) are a useful means of detecting common bile duct injuries in the operating room.

METHODS

Data were retrospectively reviewed for patients referred for management of common duct injuries from 1996 to 2000. Cost data were obtained from hospital records. Legal settlements were obtained from published sources.

RESULTS

Twenty-one patients (0.133%) were found to have bile duct injuries and incurred median hospital stays of 11.5 days at an average cost of $587,491. The average cost of those requiring reoperation was $669,134. The 21 cases in our sample had total charges of $10,819,767. Performing IOCG during each LC in Orange County would have cost $10,669,725. If extrapolated to state and nationwide levels, the savings is far greater.

CONCLUSIONS

IOCG during LC is a cost-effective means of preventing the costs of delayed recognition of bile duct injuries.

Proinflammatory chemokine induction in keratocytes and inflammatory cell infiltration into the cornea

PURPOSE

To determine the effect of interleukin (IL)-1alpha and tumor necrosis factor (TNF)-alpha on cytokine, chemokine, and receptor expression in corneal stromal cells; the effect of corneal scrape injury on monocyte chemotactic and activating factor (MCAF) expression and monocyte-macrophage influx into the stroma; and the effect of MCAF and granulocyte colony-stimulating factor (G-CSF) microinjection on inflammatory cell infiltration into the stroma.

METHODS

Gene array technology was used to evaluate changes in cytokine, chemokine, and receptor gene expression in stromal fibroblasts in response to IL-1alpha and TNFalpha. Expression of MCAF mRNA and protein was monitored with an RNase protection assay and Western blot analysis, respectively. Keratocyte MCAF protein expression in the rabbit cornea was detected with immunocytochemistry. After epithelial scrape injury, monocytes-macrophages were detected in rabbit corneas, by immunocytochemistry for monocyte-macrophage antigen. Inflammatory cell infiltration after MCAF and G-CSF microinjection into the stroma of mouse corneas was monitored with hematoxylin and eosin staining.

RESULTS

IL-1alpha or TNFalpha upregulated the expression of several proinflammatory chemokines in stromal fibroblasts in culture. These included G-CSF, MCAF, neutrophil-activating peptide (ENA-78), and monocyte-derived neutrophil chemotactic factor (MDNCF). MCAF mRNA upregulation was confirmed by RNase protection assay, and MCAF protein was detected by Western blot analysis. MCAF protein was detected in keratocytes at 4 hours and 24 hours after epithelial injury, but not in keratocytes in the unwounded cornea. Corneal epithelial injury triggered the influx of monocytes-macrophages into the corneal stroma in the rabbit. Microinjection of MCAF and G-CSF into mouse cornea resulted in the influx of monocytes-macrophages and granulocytes, respectively, into the stroma.

CONCLUSIONS

Proinflammatory chemokine induction in keratocytes is mediated by IL-1alpha and TNFalpha. The proinflammatory chemokines produced by the keratocytes probably trigger the influx of inflammatory cells into the stroma after epithelial injury associated with corneal surgery, contact lenses, or trauma.

Characterization of human and mouse angiopoietin-like factor CDT6 promoters

PURPOSE

Angiogenesis refers to the latter stage of vascular development. It has been reported that angiopoietin-like factor cornea-derived transcript 6 (CDT6) encodes a protein homologous to angiopoietins that could play a critical role in blocking a receptor of angiopoietin (Tie2) and therefore contribute to the avascularity and transparency of the cornea in the developing embryo and the adult. This study was focused on isolation and characterization of the CDT6 promoter.

METHODS

Rapid amplification of cDNA ends (5'-RACE) was used to isolate the CDT6 promoter from an adaptor-ligated genomic DNA fragment library and to identify the transcription initiation site of the CDT6 gene. The RNase protection assay was performed to confirm the initiation site. The sequence similarity, binding sites for putative transcription factors, and transcriptional activity of human and mouse CDT6 promoters were compared. Corneal and noncorneal cells from humans and other animals were transiently transfected with CDT6 promoter-chloramphenicol acetyltransferase (CAT) reporter constructs to analyze the transcriptional activity of the promoter.

RESULTS

A 2956-bp human CDT6 promoter fragment and a 3142-bp mouse CDT6 promoter fragment were isolated. The major transcription initiation sites of the human and mouse CDT6 genes were located at 224 and 168 bp, respectively, upstream of the translation initiation site. Human and mouse CDT6 promoter sequences were very similar. Both promoters were minus TATA and CAAT boxes close to the transcription initiation site. Transfection into human corneal and noncorneal cells and into nonhuman cells revealed that the human CDT6 promoter probably contains positive and negative cis-regulatory elements that modulate cell, tissue, and species specificity. The human CDT6 promoter contains four interferon (IFN)-stimulated response elements (ISREs). No ISREs could be identified in the mouse promoter. IFN-alpha stimulated transcriptional activity of the human promoter.

CONCLUSIONS

The human and mouse CDT6 promoters have similar sequences and share many cis-regulatory elements. IFN-alpha appears to have an important role in regulating transcription of the human, but not the mouse, CDT6 promoter.

Trunk posture and spinal stability

OBJECTIVE

The influence of trunk posture on musculoskeletal stability of the spine was investigated.

DESIGN

A biomechanical model was developed to evaluate the influence of posture on spinal stability. Model performance was assessed by comparing predicted muscle recruitment patterns with measured EMG activity from the trunk muscles during static lifting exertions.

METHOD

An inverted double-pendulum model of the spine controlled by 12 muscle equivalents of the trunk was implemented to determine spinal load and stability. Model input included trunk posture and lifted mass, output included muscle recruitment patterns necessary to achieve stability of the spine and spinal load. EMG activity recorded from the trunk muscles of 10 subjects were recorded during static exertions in various trunk flexion and asymmetric postures to compare with model output. Stable spinal load was examined as a function of trunk flexion and asymmetry during the lifting exertions.

RESULTS

Antagonistic co-contraction was necessary to achieve spinal stability, particularly in upright postures. Stable spinal load was increased in asymmetric postures as a result of antagonistic muscle recruitment, suggesting greater neuromuscular control is necessary to maintain stability in asymmetric lifting postures. As trunk flexion angle increased, stability improved but spinal load was greater.

CONCLUSIONS

Results illustrate that muscle recruitment patterns are more accurately explained by stability than by equilibrium alone. Spinal stability is influenced by posture. Specifically, control of spinal stability is reduced in asymmetric postures associated with low-back disorder risk.

RELEVANCE

Traditional assessment of low-back disorder risk have focussed on spinal loading. Results illustrate that postural risk factors for low-back pain may be partially attributable to stability considerations.

Laser in situ keratomileusis-induced neurotrophic epitheliopathy

PURPOSE

To report two cases of laser in situ keratomileusis-induced neurotrophic epitheliopathy with punctate epitheliopathy and rose bengal staining of the corneal flap.

METHODS

Interventional case reports.

RESULTS

A 42-year-old woman and a 37-year-old man with no preoperative symptoms or signs of dry eye developed dry eye symptoms and bilateral punctate epithelial erosions as well as rose bengal staining of the corneal flaps after laser in situ keratomileusis. Neither patient had less than 12 mm of wetting with the Schirmer test without anesthesia at any time point between development and resolution of the flap surface abnormalities. The flap surface abnormalities resolved approximately 6 months after laser in situ keratomileusis.

CONCLUSIONS

Laser in situ keratomileusis-induced neurotrophic epitheliopathy may be attributable to loss of trophic influence from severed corneal nerve trunks. The condition typically resolves approximately 6 months after laser in situ keratomileusis or laser in situ keratomileusis retreatment.

The corneal wound healing response: cytokine-mediated interaction of the epithelium, stroma, and inflammatory cells

The corneal wound healing cascade is complex and involves stromal-epithelial and stromal-epithelial-immune interactions mediated by cytokines. Interleukin-1 appears to be a master modulator of many of the events involved in this cascade. Keratocyte apoptosis is the earliest stromal event noted following epithelial injury and remains a likely target for modulation of the overall wound healing response. Other processes such as epithelial mitosis and migration, stromal cell necrosis, keratocyte proliferation, myofibroblast generation, collagen deposition, and inflammatory cell infiltration contribute to the wound healing cascade and are also likely modulated by cytokines derived from corneal cells, the lacrimal gland, and possibly immune cells. Many questions remain regarding the origin and fate of different cell types that contribute to stromal wound healing. Over a period of months to years the cornea returns to a state similar to that found in the unwounded normal cornea.

Endovascular photodynamic therapy using mono-L-aspartyl-chlorin e6 to inhibit Intimal hyperplasia in balloon-injured rabbit arteries

BACKGROUND AND OBJECTIVE

Intimal hyperplasia (IH) leading to restenosis is a major complication of arterial revascularization. The purpose of this study was to investigate the effect of photodynamic therapy (PDT) using mono-L-aspartyl chlorin e6 (NPe6) as a photosensitizer and intraluminal radial irradiation for inhibition of IH experimentally.

STUDY DESIGN/MATERIALS AND METHODS

Study of laser transmission through the blood indicated that exclusion of blood is a prerequisite for intraluminal PDT. For homogeneous radial laser irradiation to the vessel wall, we used a newly developed cylindrical diffusing balloon laser fiber. Injuries were induced by pulling a balloon catheter through the right iliac artery of rabbits. One and 6 hours after the NPe6 injection (5mg/kg i.v.), drug distribution was examined by fluorescence microscopy. Nineteen rabbits received NPe6 at the time of injuries and PDT was performed with 664-nm laser at 30 and 10 J/cm(2) (20, 30, 40 mW/cm(2)) 1 hour after the injuries. The arteries were harvested at 2 days. In a second group of rabbits, PDT was given at 30 mW/cm(2) (30 J/cm(2)). Two weeks after treatment, the arteries were removed and examined histologically.

RESULTS

NPe6 was found to be distributed selectively in the injured media. Endovascular NPe6-PDT showed complete depletion of smooth muscle cells even with 10 J/cm(2) at 2 days. IH was significantly inhibited at 14 days after PDT.

CONCLUSIONS

Endovascular PDT of injured artery using NPe6 can prevent IH in this model of arterial wall injury and may become clinically useful for the prophylaxis of IH.

Abdominal aortic aneurysm in women

OBJECTIVE

The purpose of this study was to compare abdominal aortic aneurysm (AAA) associations in men and women.

METHODS

Veterans aged 50 to 79 years without a previous history of AAA underwent ultrasound screening for AAA after completing a questionnaire on demographic information and potential risk factors.

RESULTS

A total of 122,272 men and 3450 women were successfully screened. An AAA of 3.0 cm or greater in diameter was found in 4.3% of men and 1.0% of women (P <.001). Contrary to a previous report, we did not find suprarenal aortic enlargement accompanying AAA to be more common in women. The principal associations that we have previously reported for AAA in this cohort (age, smoking, family history of AAA, and a negative association with diabetes) were all similar in women compared with men. In age- and smoking-adjusted models, the interaction terms indicated that black race and cancer were more strongly associated with AAA in women than men (P <.05). Height and cerebral vascular disease were also more strongly associated with AAA in women than in men, but these interaction terms did not reach statistical significance (P <.10). Although the other differences were unexpected and require confirmation, the trend toward a stronger association of cerebral vascular disease with AAA in women is consistent with two previous reports.

CONCLUSIONS

Despite the much lower prevalence of AAA in women, the most important associations with AAA are similar to those seen in men. Our data provide some support for a previous finding that cerebrovascular disease may be more closely associated with AAA in women than in men.

Differential expression analysis by gene array of cell cycle modulators in human corneal epithelial cells stimulated with epidermal growth factor (EGF), hepatocyte growth factor (HGF), or keratinocyte growth factor (KGF)

PURPOSE

To identify and differentiate cell cycle and differentiation genes that are up-regulated or down-regulated in human corneal epithelial cells in response to alternative epithelium-modulating cytokines epidermal growth factor (EGF), hepatocyte growth factor (HGF) or keratinocyte growth factor (KGF).

METHODS

Primary cultures human corneal epithelial cell (HCE) were treated with 25 ng/ml of EGF, 25 ng/ml HGF, 25 ng/ml KGF, or vehicle for 8 hours. Complementary DNA (cDNA) probes were synthesized from total cellular RNA isolated from the HCE cells. The cDNA probes were hybridized to the Atlas human cell cycle/differentiation array membrane. RNAse protection assay was used to confirm up-regulation of the serine/threonine-protein kinase PITALRE gene by EGF, KGF, and HGF.

RESULTS

The expression of one hundred and eleven cell cycle and differentiation genes was monitored with the gene array system. It was found that these epithelial cell-modulating cytokines shared similar effects on some of the cell cycle and differentiation genes that were monitored, but had specific effects on some cytokines. Up-regulation of PITALRE gene expression was confirmed using RNAse protection assay.

CONCLUSION

EGF, HGF and KGF had differential effects on cell cycle- and differentiation-related gene expression in corneal epithelial cells. For example, all three mitogenic growth factors up-regulated the expression of cyclin D1 (BCL-1 oncogene) and serine/threonine-protein kinase PITALRE in the primary cultured human corneal epithelial cells. However, EGF and KGF, but not HGF, up-regulated expression of the E2F-1 pRB-binding protein gene. Thus, while these three epithelial mitogens have similar effects on many genes that were analyzed, important differences were noted that may relate to differing effects of these growth factors on corneal epithelial cells. Studies to analyze the significance of the identified differences among these growth factors are in progress.

Computerized corneal topography and its importance to wavefront technology

PURPOSE

To review the development and application of corneal topography in refractive surgery.

METHODS

Review of the literature and discussion of recent developments in corneal topography and wavefront technology.

RESULTS

Analysis of corneal topography provides critical information for the preoperative examination of patients before refractive surgery and for the evaluation and treatment of patients with complications after surgery.

CONCLUSIONS

Corneal topography will continue to be a critical diagnostic modality for refractive surgery. Even with the advent of wavefront analysis designed to detect refractive error and aberrations of the eye, it will be necessary to have detailed corneal topographic information to understand the contribution the cornea makes to vision so that custom alteration of that surface can be used to optimize vision. This will be true of the normal eye, but it will be of special importance in eyes with abnormalities that were induced by corneal surgery.

Topical phenytoin treatment of stage II decubitus ulcers in the elderly

OBJECTIVE

To compare the healing of stage II decubitus ulcers with topically applied phenytoin sodium with two other standard topical treatment procedures in a long-term care setting; and to assess the extent of systemic absorption after topical application in the phenytoin group.

METHODS

Forty-seven nursing home patients with stage II decubitus ulcers were chosen for this study. The patients were matched for age, gender, and size and severity of wounds, and randomly assigned to each treatment group. Clinical assessment of decubitus ulcers was performed at the beginning of treatment and at each dressing change. Ulcers were examined for the presence of healthy granulation tissue, reduction in surface dimensions, and time to healing. Two phenytoin sodium plasma concentrations were to be obtained on all patients in the phenytoin group.

RESULTS

Topical phenytoin therapy resulted in a shorter time to complete healing and formation of granulation tissue when compared with DuoDerm dressings or triple antibiotic ointment applications (p < or = 0.05). The mean +/- SD time to healing in the phenytoin group was 35.3 +/- 14.3 days compared with 51.8 +/- 19.6 and 53.8 +/- 8.5 days for the DuoDerm and triple antibiotic ointment groups, respectively. Healthy granulation tissue in the phenytoin group appeared within two to seven days in all subjects. Patients in the standard treatment groups required six to 21 days to produce new granulation tissue. Serum phenytoin sodium concentrations were nondetectable. No patient withdrew from the study secondary to adverse treatment effects.

CONCLUSIONS

Both the phenytoin and standard treatment groups showed progress over the study period. However, the phenytoin group demonstrated more rapid results in all aspects of ulcer healing.

Laser in situ keratomileusis-induced (presumed) neurotrophic epitheliopathy

OBJECTIVE

To evaluate tear production, corneal topography, accuracy of refractive correction, and best spectacle-corrected visual acuity in eyes that had moderate to severe rose bengal staining develop on the flap compared with eyes with little or no staining on the flap, the first few months after laser in situ keratomileusis (LASIK). None of the eyes in this study had significant preoperative dry eye disease.

DESIGN

Retrospective case control study.

PARTICIPANTS

Individual eyes of 19 consecutive patients with moderate to severe punctate epithelial erosions and rose bengal staining on the flap 1 to 3 months after LASIK were compared with eyes of 19 concurrent patients who did not have punctate epithelial erosions or more than trace staining on the flap develop.

METHODS

Nonparametric statistical analyses were used to compare tear secretion, corneal topographic irregularity, spherical equivalent, and visual acuity 3 and 6 months after surgery. Some eyes in both groups also had analysis of tear secretion 1 month after surgery.

MAIN OUTCOME MEASURES

Schirmer's test without anesthesia, the topographic corneal irregularity measurement (CIM), the difference between attempted and achieved spherical equivalent, and the loss of best spectacle-corrected visual acuity.

RESULTS

There was no difference in tear production 1, 3, or 6 months after LASIK in patients who had punctate epithelial erosions and rose bengal staining on the flap develop and those who did not. There was no significant difference in the CIM or mean accuracy of the refractive correction in the two groups, but some patients had a transient decrease in best spectacle-corrected visual acuity. Flap rose bengal staining resolved by 6 months after LASIK in most affected patients.

CONCLUSIONS

LASIK-induced rose bengal staining in patients without preexisting dry eye is likely neurotrophic epitheliopathy, because there is no difference in mean tear production between patients who have significant punctate epithelial erosions and rose bengal staining develop on the flap and those who do not. The signs and symptoms of LASIK-induced (presumed) neurotrophic epitheliopathy tend to resolve approximately 6 months after surgery. This disorder tends to be more common and severe in patients with pre-existing dry eye disease.