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Biomedical subjects

S E Wilson

Publications and source records attributed to S E Wilson.

At least 127 records · Page 7Linked to original sources
PubMed1997

Analysis of corneal topography after automated lamellar keratoplasty.

PURPOSE: The purpose of the study is to evaluate the effects of myopic automated lamellar keratoplasty (ALK) on corneal topography. METHODS: The authors performed a retrospective study of computer-assisted topographic maps obtained before surgery and at the last follow-up visit of 9 patients (13 eyes) who underwent ALK without enhancement to correct moderate-to-high myopia during a 12-month period. RESULTS: Follow-up ranged from 3.5 to 13 months (mean, 5.8; standard deviation, 3.1). The mean manifest spherical equivalent changed from -10.5 +/- 2.2 diopters (D) before surgery to -1.1 +/- 1.8 D at the last follow-up visit. Mean simulated keratometry (Sim K) decreased from 45.6 +/- 1.9 D to 38.9 +/- 2.7 D. Mean corneal astigmatism increased from 1.3 +/- 0.8 D to 2.1 +/- 0.9 D. The mean surgically induced cylinder vector (calculated by vector analysis) was 1.1 +/- 0.6 D. Mean surface regularity index (SRI) and surface asymmetry index (SAI) increased from 0.37 +/- 0.38 and 0.32 +/- 0.43 before surgery to 1.00 +/- 0.32 (P < 0.001) and 0.75 +/- 0.36 (P = 0.01), respectively, at the last visit. A positive correlation was observed between the decrease in mean Sim K and the increase in manifest spherical equivalent (reduction of myopia) (r = 0.77, P = 0.002), increase in SRI (r = 0.73, P = 0.005), and increase in SAI (r = 0.58, P = 0.04). The change in manifest spherical equivalent was significantly less than the change in Slm K (P < 0.001). CONCLUSIONS: Myopic ALK significantly flattens the cornea and reduces myopia. However, it induces corneal astigmatism and decreases corneal surface regularity and symmetry. The degree of myopic correction, as well as the surgically induced corneal surface irregularity and asymmetry, is positively correlated with the amount of corneal flattering derived from the surgical procedure.

Adult↗
PubMed1997

Small-diameter, round, eccentric penetrating keratoplasties and corneal topographic correlation.

PURPOSE: The purpose of the study is to report the outcome and postoperative topographic analysis of seven patients who underwent small-diameter, round, eccentric penetrating keratoplasty. METHODS: Seven patients underwent small-diameter, round, eccentric penetrating keratoplasty for a variety of corneal disorders (cataract wound necrosis and dehiscence or fistula, three patients; penetrating keratoplasty wound infection, two patients; corneal rheumatoid melt and perforation, one patient; localized fungal keratitis, one patient). Full-thickness corneal transplants ranged in size from 3.0 to 5.5 mm. The graft wound and sutures spared the visual axis in all cases. Patients were observed for 7 to 42 months (mean, 21 months). All patients had postoperative topographic analysis. One of these also had preoperative analysis. RESULTS: All grafts tectonically were effective in treating the intended condition. Best-corrected visual acuity was 20/30 or better in the four patients without pre-existing corneal transplants or dry eyes; 20/60 and 5/200 in the patients with previous central penetrating keratoplasties; and 20/40 in the patient with rheumatoid melt. There was no clinically significant regular or irregular astigmatism induced centrally by the eccentric graft in the four patients where visual acuity was 20/30 or better. Irregular astigmatism was noted in the other three patients. CONCLUSION: Small-diameter, eccentric penetrating keratoplasties may be used successfully to treat various peripheral corneal disorders. In some cases, this can be performed without inducing high or irregular astigmatism or both centrally.

Adult↗
PubMed1997

Relationship of age, gender, race, and body size to infrarenal aortic diameter. The Aneurysm Detection and Management (ADAM) Veterans Affairs Cooperative Study Investigators.

PURPOSE: To assess the effects of age, gender, race, and body size on infrarenal aortic diameter (IAD) and to determine expected values for IAD on the basis of these factors. METHODS: Veterans aged 50 to 79 years at 15 Department of Veterans Affairs medical centers were invited to undergo ultrasound measurement of IAD and complete a pre-screening questionnaire. We report here on 69,905 subjects who had no previous history of abdominal aortic aneurysm (AAA) and no ultrasound evidence of AAA (defined as IAD > or = 3.0 cm). RESULTS: Although age, gender, black race, height, weight, body mass index, and body surface area were associated with IAD by multivariate linear regression (all p < 0.001), the effects were small. Female sex was associated with a 0.14 cm reduction in IAD and black race with a 0.01 cm increase in IAD. A 0.1 cm change in IAD was associated with large changes in the independent variables: 29 years in age, 19 cm or 40 cm in height, 35 kg in weight, 11 kg/m2 in body mass index, and 0.35 m2 in body surface area. Nearly all height-weight groups were within 0.1 cm of the gender means, and the unadjusted gender means differed by only 0.23 cm. The variation among medical centers had more influence on IAD than did the combination of age, gender, race, and body size. CONCLUSIONS: Age, gender, race, and body size have statistically significant but small effects on IAD. Use of these parameters to define AAA may not offer sufficient advantage over simpler definitions (such as an IAD > or = 3.0 cm) to be warranted.

Aged↗
PubMed1997

Inhibitory effect of type 1 collagen gel containing alpha-elastin on proliferation and migration of vascular smooth muscle and endothelial cells.

The purpose of this study was to investigate in vitro the potential effect of type 1 collagen gel containing alpha-elastin on the proliferation of vascular smooth muscle cells and vascular endothelial cells, and on smooth muscle cell migration. Vascular smooth muscle cell and endothelial cell were cultured in 12-well plates precoated with collagen gels and alpha-elastin. Cell proliferation rates were measured by monitoring [3H]-thymidine incorporation. After 2, 3 or 4 days of culture, the proliferation rate of both smooth muscle cells and endothelial cells was significantly decreased on collagen gel containing 10 mg/ml alpha-elastin compared with collagen gel only as control. Smooth muscle cell proliferation on collagen gel containing alpha-elastin on the 4th day of culture was decreased dose-dependently, e.g. 1 mg/ml of alpha-elastin (74.8(2.3)% of control, P=n.s.); 5 mg/ml (56.7(2.1)%; P<0.05); 10 mg/ml (30.3(3.1)%; P<0.005). In the case of cultured endothelial cells, however, [3H]-thymidine incorporation was not decreased significantly in the presence of 5 mg/ml alpha-elastin (83.1(7.9)%, P=n.s.). After stimulation by platelet-derived growth factor, the smooth muscle cell migration rate on collagen gel containing alpha-elastin (5 mg/ml) was decreased over time. The area of migration on the 6th day of culture was also significantly decreased dose-dependently in the presence of alpha-elastin, e.g. 1 mg/ml (72.6(3.4)% of control, P<0.05), 5 mg/ml (56.9%(1.5)%; P<0.05); 10 mg/ml (37.3(2.7)%; P<0.0005). In conclusion, alpha-elastin inhibited the proliferation and migration of smooth muscle cell in a dose-dependent manner on collagen gel culture, however, at high concentrations of alpha-elastin (10 mg/ml), the endothelial cell proliferation rate was also inhibited. At 5 mg/ml, alpha-elastin significantly inhibited smooth muscle cell proliferation and migration but did not significantly inhibit endothelial cell proliferation. Incorporation of collagen gel containing alpha-elastin into the structure of arterial prosthesis offers the possibility of inhibiting smooth muscle cell hyperplasia without significant effect on endothelial cell formation.

Animals↗
PubMed1997

In defense of routine antimicrobial susceptibility testing of operative site flora in patients with peritonitis.

The species and number of bacteria present at a surgical site correlate with postoperative wound infection. When organisms cultured from intraabdominal infections are resistant to the presumptive antimicrobial therapy, the incidence of postoperative wound and intraabdominal infections is significantly increased. Knowledge of operative site culture data allows identification of resistant organisms, leads to an early change in therapy, and guides selection of antimicrobials for treatment of postoperative complications. Anaerobic susceptibility data vary geographically, even differing within hospitals in the same city. Surveillance of resistance patterns of bacteria causing intraabdominal infections facilitates accurate initial therapy. Failure of treatment in the absence of bacteriologic results confirming appropriate antimicrobial therapy may be difficult to rationalize on a medicolegal basis. In summary, it is advisable for surgeons to perform cultures and susceptibility tests for both aerobic and anaerobic organisms present in intraabdominal infections.

Bacteria, Anaerobic↗
PubMed1997

Results of a randomized, multicenter trial of meropenem versus clindamycin/tobramycin for the treatment of intra-abdominal infections.

In a randomized, double-blind clinical trial conducted at 13 medical centers, meropenem (1,000 mg given iv every 8 hours) was compared with the combination of clindamycin (900 mg every 8 hours) plus tobramycin (5 mg/[kg.d] in three divided doses) given iv for the treatment of intra-abdominal infections that required surgery and parenteral antibiotic therapy. At the end of treatment, efficacy data on patients who met study inclusion criteria (intent-to-treat) were available for 132 of 215 patients in the meropenem group and 134 of 212 patients in the clindamycin/tobramycin group; 120 (91%) of 132 intent-to-treat patients in the meropenem group were cured, 115 (86%) of 134 intent-to-treat patients in the clindamycin/tobramycin group were cured (P value, not significant). Of the patients treated with meropenem and considered evaluable according to the study protocol, 89 (92%) of 97 were cured, and 81 (86%) of 94 patients treated with clindamycin/tobramycin and considered evaluable were cured. Bacteriologic response rates for all evaluable patients (n = 191) were 96% (93 of 97 patients) among those randomized to the meropenem arm and 93% (87 of 94) among those randomized to the clindamycin/tobramycin arm. Adverse events occurred with similar frequency in both treatment groups; neither seizures nor deaths related to treatment were reported for any patients in either group. The results of this trial demonstrated that meropenem, together with appropriate surgical intervention, was safe and effective in the treatment of patients who had bacterial intra-abdominal infections, most of which were secondary to complicated appendicitis.

Abdominal Abscess↗
PubMed1997

Expression of HGF, its receptor c-met, c-myc, and albumin in cirrhotic and neoplastic human liver tissue.

Hepatocellular carcinoma (HCC) is a common type of cancer, with approximately 260,000 new cases each year, and liver cirrhosis is generally considered a major predisposing factor for HCC. However, specific changes of gene expression in liver cirrhosis and HCC remain obscure. The expression of genes for hepatocyte growth factor (HGF), its receptor c-met proto-oncogene, c-myc proto-oncogene, and albumin was analyzed. Gene expression was studied by PCR in seven normal human livers, nine cases of hepatitis C cirrhosis, 12 cases of alcoholic cirrhosis, two cases of liver adenoma, and 12 cases of HCC. HGF and c-met protein were revealed by immunofluorescent staining. HGF mRNA was not expressed in normal livers but was detected in adenomas, in 80% of HCC, and in some cirrhoses. Paraffin-embedded and fresh-frozen tissue samples yielded similar results. Immunohistochemical data correlated with PCR results regarding the overexpression of the HGF/c-met system in HCC. Albumin gene expression was decreased in HCC vs normal livers, consistent with altered function of tumor hepatocytes. The elevated expression of the HGF/c-met system in HCC may play a role in tumor development and/or progression. Tissue localization studies of HGF and its receptor c-met protein support the existence of both autocrine and paracrine mechanisms of action of HGF in HCC vs only a paracrine mechanism in normal liver.

Adenoma, Liver Cell↗
PubMed1997

Characterization of SV40-transfected cell strains from rabbit keratocytes.

The process of corneal wound healing involves the transformation of adjacent corneal keratocytes to myofibroblast-like cells characterized by the development of prominent microfilament bundles containing alpha-smooth muscle-specific actin (alpha-SM), a contractile protein thought to be important in mediating wound contraction. Recent studies have shown that the expression of alpha-SM in cultured corneal keratocytes can be induced by serum and TGF beta 1. To study the cellular and molecular mechanisms underlying this transformation process and to begin to identify the role of alpha-SM in wound contractile events, we generated immortalized rabbit corneal cell strains with extended life by using SV40 transfection. Two unique strains were isolated (TRK-36 and TRK-43). TRK-36, which appears similar to normal corneal keratocytes, maintains a stellate, keratocyte morphology when grown in the absence of serum and transforms to a myofibroblast-like cell when treated with TGF beta 1 (1 ng/ml), as indicated by the induced expression of alpha-SM actin. TRK-43 exhibits features characteristic of myofibroblasts in that it constitutively expresses alpha-SM actin under serum-free conditions. Both strains show in vitro contraction of collagen gels < or = 80% in 24 h in serum-containing medium. Interestingly, under serum-free conditions, TRK-43 cells showed significantly greater contraction of collagen gels compared with those of TRK-36. Overall, the establishment and further study of these cell strains may provide important insights into the molecular mechanisms underlying myofibroblast transformation.

Actins↗
PubMed1997

Epithelial growth within the lamellar interface after laser in situ keratomileusis (LASIK)

PURPOSE: To report the occurrence and follow-up of ectopic, interface, epithelial growth after laser in situ keratomileusis (LASIK) in four eyes (three patients) and provide suggestions for management. METHODS: Each eye was examined by slit-lamp biomicroscopy, and corneal topography was obtained with the Tomey TMS-1 instrument. RESULTS: Each eye with epithelium within the interface after LASIK developed interface opacities and surface irregularity. One eye had an early surgical intervention, and three eyes were observed. Each eye lost at least one line of best spectacle-corrected visual acuity and had visual disturbance at the last follow-up visit. CONCLUSIONS: The presence of epithelium within the lamellar interface is a significant complication after LASIK. In some cases, interface epithelium may be associated with early postoperative inflammation. When reoperation is required to treat this complication, we suggest scraping of both sides of the interface with a metal blade. In some cases, light excimer laser treatment can be used to facilitate epithelial removal.

Adult↗
PubMed1997

IL-1 upregulates keratinocyte growth factor and hepatocyte growth factor mRNA and protein production by cultured stromal fibroblast cells: interleukin-1 beta expression in the cornea.

PURPOSE: To determine whether interleukin 1 beta (IL-1 beta) messenger RNA (mRNA) and protein were expressed in corneal cells and to examine the effects of IL-1 alpha and IL-1 beta on the expression of hepatocyte growth factor (HGF) and keratinocyte growth factor (KGF) mRNAs and proteins in corneal stromal fibroblasts. METHODS: IL-1 beta mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). IL-1 beta protein was detected by immunohistologic tests. Changes in the expression of HGF and KGF mRNAs and proteins in response to stimulation of cultured corneal stromal fibroblasts with IL-1 alpha and IL-1 beta were monitored by Northern and Western blotting, respectively. RESULTS: IL-1 beta mRNA is expressed in human primary cultured corneal epithelial, stromal fibroblast, and endothelial cells. IL-1 beta protein was detected in epithelium and endothelium in fresh frozen human and rabbit corneal tissue. Little, if any, IL-1 beta was detected in the unwounded corneal stroma. IL-1 alpha and IL-1 beta at 10 ng/ml upregulated the levels of HGF and KGF mRNAs and proteins in cultured human corneal fibroblasts. CONCLUSIONS: IL-1 alpha and IL-1 beta may serve as key modulators in an epithelial-stromal regulatory loop in the cornea. These data and previously published observations support the hypothesis that corneal epithelial wounding releases IL-1 alpha and IL-1 beta from epithelial cells; these cytokines in turn upregulate HGF and KGF mRNA and protein levels in keratocytes, and HGF and KGF released by the keratocytes modulate healing of the wounded corneal epithelial cells by regulating proliferation, motility, and differentiation.

Animals↗
PubMed1997

Hepatocyte growth factor, keratinocyte growth factor, and other growth factor-receptor systems in the lens.

PURPOSE: To examine the expression and function of hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), epidermal growth factor (EGF) and other growth factor-cytokine-receptor systems in lens epithelial cells. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot analysis were used to examine the expression of messenger RNAs in primary cultured rabbit and human lens cells and in ex vivo rabbit lens tissue. Protein expression and the effect of HGF and KGF on crystallin expression in lens epithelial cells were evaluated by immunoprecipitation and Western blot analysis. The effect of exogenous HGF, KGF, and EGF and of the coculture of lens epithelial cells with corneal endothelial cells on the proliferation of rabbit lens cells in a Transwell system was determined by cell counting. RESULTS: Messenger RNAs and proteins of HGF and KGF were expressed in primary rabbit lens epithelial cells and in ex vivo rabbit lens epithelial tissue. Human lens cells also expressed the mRNAs. Other growth factors and receptor messenger RNAs were also expressed. Hepatocyte and keratinocyte growth factors, and coculture with corneal endothelial cells stimulated proliferation of rabbit lens epithelial cells. In first-passage rabbit lens cells, HGF, KGF, and EGF increased the expression of alpha and beta crystallins. CONCLUSIONS: Hepatocyte and keratinocyte growth factor-receptor systems are expressed in lens cells. HGF and KGF are not expressed in epithelial cells in such tissues as skin, cornea, and lacrimal gland in which fibroblastic and epithelial cells interact in the formation of an organ. Expression of these growth factors in the lens may have evolved because the lens cells are relatively isolated within the anterior chamber of the eye. Our results suggest, however, that growth factors released by the corneal endothelium also could modulate lens functions (aquecrine interactions).

Animals↗
PubMed1997

Effects of 50% ethanol and mechanical epithelial debridement on corneal structure before and after excimer photorefractive keratectomy.

PURPOSE: The corneal epithelium is generally removed before photoablation in photorefractive keratectomy (PRK) because laser transepithelial PRK may result in surface irregularity caused by variability in epithelial thickness and differing ablation rates between epithelium and stroma. We compared the effects of mechanical deepithelialization with chemical epithelial removal by using 50% ethanol on the corneal structure. METHODS: Fourteen rabbits underwent corneal deepithelialization by using a blade in the left eye and 24 h later in the right eye. Another 14 rabbits underwent corneal deepithelialization by using 50% ethanol solution. Half of the eyes treated with each technique underwent PRK after deepithelialization. Pachymetry was performed before and after each procedure on right eyes. Keratocyte and neutrophil densities were assessed by light microscopy. RESULTS: Among non-laser-treatment groups, eyes that underwent mechanical deepithelialization had decreased corneal thickness (p = 0.001), increased keratocyte densities (p = 0.03), and no significant difference in neutrophil densities (p = 0.91) compared with chemically treated eyes 24 h after surgery. Among laser-treatment groups, eyes that underwent mechanical epithelial removal had increased keratocyte densities (p = 0.001), decreased corneal thickness (p = 0.03), and increased neutrophil densities (p = 0.03) 24 h after surgery compared with chemically treated eyes. CONCLUSION: Deepithelialization with 50% ethanol causes more keratocyte loss with perhaps more corneal edema, but less stromal influx of neutrophils, than does a mechanical technique 24 h after PRK in a rabbit model. Corneal deepithelialization with dilute ethanol may be a viable option in PRK. However, further investigation into the safety of this technique is warranted before it can be widely applied clinically.

Administration, Topical↗
PubMed1996

Effect of activation of protein phosphatase 1 on sulfhydryl reactivity.

Myofibril protein phosphatase 1 (PP1) from bovine heart, identified as PP1alpha, was purified in a latent form which was dependent on Co2+ or Mn2+ for activity (Y. Chu, S. E. Wilson, and K. K. Schlender (1994) Biochim. Biophys. Acta 1208, 45-54). This was also true for recombinant PP1 alpha expressed in Escherichia coli (Z. Zhang, G. Bai, S. Deans-Zirattu, M. F. Browner, and E. Y. C. Lee (1992) J. Biol. Chem. 267, 1484-1490). Here we report on the change in the sulfhydryl reactivity during the cation activation process. The activation of myofibrillar PP1 by Co2+ was prevented by 10 mM dithiothreitol (DTT) and incubation of the Co2+-activated enzyme with 50 mM DTT reversed the activation. Activation of recombinant PP1alpha was associated with 57Co2+ incorporation into PP1. DTT reversal of Co2+-activated PP1 was accompanied by release of Co2+ from the enzyme. The latent PP1 modified with 2-nitro-5-thiocyanobenzoic acid (NTCB) or N-ethylmaleimide (NEM) did not bind Co2+ and could not be activated by Co2+. Conversely, the Co2+-activated PP1 was resistant to inactivation with NTCB and less sensitive to NEM. Similarly, PP1 pretreated with NTCB was not activated by Mn2+ and the Mn2+-activated enzyme was also resistant to NTCB inhibition. The number of sulfhydryls of nondenatured PP1, reactive with 5, 5'-dithiobis[2-nitrobenzoic acid] (DTNB), was reduced from approximately 8 to 2-3 mol/mol when the enzyme was activated with Co2+ or Mn2+. After denaturation with guanidine-HCl, the number of reactive sulfhydryls of nonactivated PP1 and Co2+-activated PP1 was approximately 10 mol/mol enzyme. These results suggest that when PP1 is activated by Co2+ or Mn2+, the enzyme undergoes a conformational change resulting in some of the cysteine sulfhydryls no longer being accessible to chemical modification.

Animals↗
PubMed1996

Epithelial injury induces keratocyte apoptosis: hypothesized role for the interleukin-1 system in the modulation of corneal tissue organization and wound healing.

The purpose of this study was to determine the role of programmed cell death (apoptosis) in the disappearance of keratocytes beneath an epithelial debridement wound in the cornea and to investigate a potential role of interleukin-1 (IL-1) in induction of apoptosis in stromal fibroblasts in vitro and keratocytes in vivo. Keratocyte and stromal fibroblast cell morphology was examined in wounded and unwounded mouse corneas using transmission electron microscopy. Nuclear DNA fragmentation was detected with the TUNEL assay for 3'-hydroxyl DNA ends. The effect of IL-1 on keratocytes in vivo was determined by microinjection of IL-1 alpha into the central corneal stroma via a limbal entry site. The in vitro effects of interleukin-1 alpha (IL-1 alpha) and interleukin-1 beta (IL-1 beta) were determined with primary cultures of human corneal stromal and dermal fibroblasts. Cell shrinkage, blebbing with formation of membrane bound bodies, condensation and fragmentation of the chromatin, and DNA fragmentation, consistent with apoptosis were detected in anterior stromal keratocytes after epithelial scrape wounds. Thus, disappearance of keratocytes from the underlying stroma following epithelial debridement is mediated by apoptosis. Microinjection of IL-1 alpha into the central stroma of the mouse cornea caused a redistribution of keratocytes in the stroma via apoptosis and, possibly, negative chemotaxis. IL-1 alpha and IL-1 beta induced apoptosis in corneal stromal and dermal fibroblasts in vitro. The epithelial/endothelial-stromal IL-1 system may mediate corneal tissue organization and responses to mechanical- and pathogen-induced injury through induction of keratocyte apoptosis. Keratocyte apoptosis is likely an initiating event in wound healing following corneal surgery. We hypothesize that derangement's in this system may have a role in the pathogenesis of keratoconus and other diseases of the cornea.

Animals↗
PubMed1996

Preservation of the pelvic circulation during infrarenal aortic surgery.

Paraplegia, ischemia of the colon, and gluteal necrosis are uncommon but devastating sequelae of surgery of the infrarenal aorta. These complications are ischemic in nature, secondary to the following technical maneuvers, individually or in combination: bilateral occlusion of the hypogastric arteries; division of a patent inferior mesenteric artery; or proximal end-to-end aortic to common femoral artery bypass grafting accompanied by stenosis of the external iliac arteries. The etiology of paraplegia after infrarenal aortic surgery is of particular interest since it now appears that it is more likely due to interruption of flow to lumbosacral branches of the hypogastric arteries supplying the conus of the spinal cord and/or to division of a low-lying 'conus medullaris artery' rather than to occlusion of the higher-lying great radicularis artery of Adamkiewicz. Knowledge of the pelvic circulation to the colon, buttocks, and terminal spinal cord allows the surgeon prophylactically to avoid or reconstruct critical branches during operations on the infrarenal aorta. While rare, severe complications cannot be completely eliminated; hopefully their incidence can be reduced by an understanding of their etiology.

Anastomosis, Surgical↗
PubMed1996

Phenobarbital minimally alters plasma concentrations of losartan and its active metabolite E-3174.

Losartan, a selective angiotensin II (AT1) receptor antagonist for hypertension, is metabolized to an active carboxylic acid metabolite, E-3174, which has a longer half-life. To investigate the effects of induction of cytochrome P450 on the metabolism of losartan, we evaluated the effects of phenobarbital on the plasma profiles of losartan and E-3174 in 15 healthy male subjects. Ten subjects received a single 100 mg oral dose of losartan before and during phenobarbital administration (100 mg/day for 16 days), and five subjects received losartan before and during placebo. Urinary excretion of 6-beta-hydroxycortisol (relative to 17-hydroxycorticosteroids) was measured as an endogenous marker of cytochrome P450 induction. The geometric mean area under the plasma concentration-time curve ratios (with/without phenobarbital and 90% confidence intervals) for losartan and its metabolite (E-3174) were 0.795 (0.723, 0.875) and 0.799 (0.778, 0.820), respectively, indicating that phenobarbital treatment significantly but to a clinically minor extent reduced plasma concentrations of losartan and E-3174 (p<0.01). Half-life values of losartan and E-3174 were unchanged. The ratio of 6-beta-hydroxycortisol to 17-hydroxycorticosteroids doubled in the phenobarbital group (p < 0.001) and did not change appreciably in the placebo group.

Adult↗
PubMed1996

The surgical management of aortoenteric fistulas.

Aortoenteric fistulas are serious and life-threatening complications of aortic surgery. Their exact pathogenesis is unknown, but mechanical erosion or infection leading to suture line failure are likely mechanisms. The presentation of an aortoenteric fistula can be seen months to years following the original operation, and clinical suspicion remains the cornerstone for diagnosis. When it is suspected, a prompt diagnostic work-up should be pursued in the absence of a readily recognizable source of hemorrhage. Once it is found, either by diagnostic studies or emergency laparotomy, repair can be accomplished by in situ graft replacement or extra-anatomic bypass with closure of the aortic stump. Thorough debridement of the aorta and perigraft tissues is essential for success and patient survival. As perioperative preparation and surgical techniques evolve, so too will the controversy concerning the optimal method for repair.

Aortic Diseases↗