Frequency of indicator bacteria, Salmonella and diarrhoeagenic Escherichia coli pathotypes on ready-to-eat cooked vegetable salads from Mexican restaurants.

UNLABELLED: The presence of coliform bacteria, faecal coliforms, Escherichia coli, diarrhoeagenic E. coli pathotypes (DEP) and Salmonella were determined in ready-to-eat cooked vegetable salads (RECS) from restaurants in Pachuca city, Mexico. The RECS were purchased from three types of restaurants: national chain restaurants (A), local restaurants (B) and small restaurants (C). Two restaurants for each A and B, and three for C, were included. Forty RECS samples were purchased at each A and B restaurant and 20 at each C restaurant. Of the overall total of 220 analysed samples, 100, 98·2, 72·3, 4·1 and 4·1% had coliform bacteria, faecal coliforms, E. coli, DEP and Salmonella, respectively. Identified DEP included enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC) and Shiga toxin-producing E. coli (STEC). The EPEC, ETEC and STEC were isolated each from 1·4% of samples. No E. coli O157:H7 were detected in any STEC-positive samples. The analysis of Kruskal-Wallis anova and median test of microbiological data showed that the microbiological quality of RECS did not differ between the different restaurants (P > 0·05). SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report regarding microbiological quality and Salmonella, enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC) and Shiga toxin-producing E. coli (STEC) isolation from ready-to-eat cooked vegetable salads from Mexican restaurants. Ready-to-eat cooked vegetable salads could be an important factor contributing to the endemicity of EPEC, ETEC and STEC, and Salmonella caused gastroenteritis in Mexico.

[Experience in surgical management of rectal prolapse in two hospitals in Mexico City]. / Experiencia del tratamiento quirúrgico del prolapso rectal en dos hospitales de tercer nivel en la ciudad de México.

BACKGROUND: Rectal prolapse is defined as a falling out of place of the rectum through anus. Surgery is the treatment of choice to reverse abnormal anatomy and to improve anorectal function. OBJECTIVE: To review the experience in recent years of surgical management of rectal prolapse in the Hospital Central Militar and Instituto Nacional de Ciencias Medicas y Nutrición Salvador Zubiran. METHODS: All patients with rectal prolapse who underwent surgical treatment between January 1993 through December 2008 at two institutions in Mexico City were included. Clinical information was obtained of the clinical files in both hospitals. Main study variables were age, sex, degree of prolapse, morbility and type of surgery performed. RESULTS: Fifty seven patients were included, predominantly female (59.6%) with a mean age of 45 years. The most frequent diagnosis was complete rectal prolapse. Fifteen patients (26%) were treated by perineal procedure and 42 (74%) through abdomen: 17 (40%) open and 25 (60%) laparoscopic. Morbidity rate was lower in the laparoscopic group with less length of hospital stay and a lower blood loss, but with higher recurrence rate. CONCLUSIONS: Although the laparoscopic surgery showed advantage related with a less morbility, blood loss and hospital stay, it showed higher recurrence rates."

[Pelvic angiomyxoma. A case report from National Institute of Medical Sciences and Nutrition, Salvador Zubiran.]. / Angiomixoma pélvico. Informe de un caso en el Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán.

An angiomyxoma is a pelvic neoplasia compound of myofibroblasts. This is a case report of a 41 years old female patient, who presented with a painful, pelvic mass, identified by a tomography with malignant characteristics. Total surgical excision was performed and coursed with good evolution time.

[Hereditary non-polyposis colorectal cancer associated with hereditary gastric cancer. A case report.]. / Cáncer colorrectal hereditario no polipósico asociado a cáncer gástrico hereditario. Informe de un caso.

The information regarding the association of gastric cancer and type 2 Lynch syndrome is limited. Previous studies have reported that both entities may be present in the same individual in less than 5% of the cases. The most frequent form of hereditary colorectal cancer is the Lynch syndrome or Hereditary Non-polyposic Colorectal Cancer, which is associated with germ-line mutation mostly of two genes, MLH1 and MSH2, which account for almost 90 percent of all identified mutations. The hereditary diffuse gastric cancer syndrome is caused by a germ-line mutation in the E-cadherin (CDH1) gene; only about 50 families with this syndrome have been reported. We present a case report of a patient who was diagnosed with both syndromes.

[Factors associated with survival in liver resection for metastatic colorectal carcinoma]. / Factores asociados a superviviencia en la resecciónhepática por metástasis de cáncer de colon y recto. Experiencia en el Instituto de Ciencias Médicasy Nutrición "Salvador Zubirán".

BACKGROUND: The liver is the organ in which often metastasize primary tumors. Knowledge of the etiology and forms of presentation of metastatic disease is key to deciding on the different treatment options. OBJECTIVE: Describe the surgical management of liver metastases in colorectal cancer and factors that affect the survival of patients. PATIENTS AND METHODS: We reviewed 43 cases of patients with metastatic liver cancer of the colon or rectum, who underwent liver surgery, attended January 1990 to December 2007. We analyzed demographic variables and perioperative associated with the survival of patients. There was the course and type of postoperative complications as well as the direct causes of mortality. RESULTS: Were conducted mostly metastasectomies (n = 25), followed by right hepatectomy (n = 9),and left hepatectomy (n = 9). Surgical mortality was 4.6% (n = 2). The survival rate at 1, 3 and 5 year were 45% (18 patients), 42.5% (18 patients)and 12.5% (5 patients), respectively. The presence of a single metastatic lesion (p = 0.006), size of the lesion larger than 5 cm (p = 0.003), positive lymph nodes (p = 0.002), synchronous tumor (p = 0.04),presence of extra hepatic disease (p = 0.01), positive margin (p = 0.001) and blood loss >2000 mL were significantly associated with a lower survival rate. CONCLUSION: After hepatic resection for metastatic colorectal cancer the presence of more than one tumor, > of 5 cm, with presence of synchronous tumor, nodes and positive margins, extra hepatic disease, as well blood loss > 2000 mL are factors associated with a worse survival.

[Laparoscopic colorectal surgery: third level center experience.]. / Cirugía colorrectal laparoscópica:experiencia en un centro de tercer nivel.

BACKGROUND: The role of laparoscopic surgery in the management of colorectal pathologies is steal unclear. Some new evidence has shown some advantages over open procedures. Because it is a technically demanding procedure, the progress is very low, and used among few colorectal surgeons. OBJECTIVE: To describe the experience of laparoscopic colorectal surgery in a third level referral center, in a fourth year period. We analyzed short and median outcomes, for benign and malignant diseases. MATERIAL AND METHODS: A retrospective review of all colorectal laparoscopic procedures was analyzed in a period between June 2003 and July 2007. Procedures for benign and malignant diseases were included. RESULTS: One hundred and seventy cases were included, 52 (30%) for malignant and 118 (70%)for benign diseases. The main indication for surgery was diverticular disease followed by colorectal cancer and the most common procedure was sigmoidectomy followed by right colectomy. Conversion rate was 8.8% (15 patients) and overall morbidity and mortality were 12%, and less than 1% respectively.Oncologic results were evaluated with a median follow up of 2 years, for a loco regional recurrence rate of 6%. Mean number of nodes retrieved in the pathologic specimen were 15.69 (+/- 3.53). All malignant cases had negative margins. CONCLUSIONS: Laparoscopic colorectal procedures are safe and feasible, in large volume centers showing equivalent results when comparing with open procedures evidenced in world literature,about results of oncologic cases, due to the short follow up period we can t conclude about oncologic outcomes.

Laparoscopic total proctocolectomy with ileal pouch anal anastomosis for ulcerative colitis and familial adenomatous polyposis: initial experience in Mexico.

BACKGROUND: Since the introduction of laparoscopic colectomy in 1991, experience in laparoscopic bowel surgery has gradually increased. Several reports from specialized centers have demonstrated that laparoscopic colorectal resections are feasible and safe, providing an acceptable alternative to laparotomy for a variety of diseases. Some studies have shown the feasibility, safety, and good functional outcome of the minimally invasive procedures for ulcerative colitis (UC) and familial adenomatous polyposis (FAP). No known studies have investigated laparoscopic proctocolectomy in México. This report aims to describe the first laparoscopic proctocolectomies with ileal pouch anal anastomosis (IPAA) performed at the Instituto Nacional de Ciencias Medicas y Nutrición Salvador Zubirán (INCMNSZ). METHODS: All the patients in the authors' institution who underwent a one- or two-stage laparoscopic total proctocolectomy with IPAA between June 2005 and December 2006 were included in the study. All the operations were performed by the same surgeon, who had already completed the learning curve for colorectal laparoscopic procedures. RESULTS: For the study, 10 patients underwent a laparoscopic proctocolectomy with IPAA by a single surgeon. Eight of the patients underwent a one-stage procedure, whereas two patients with severe colitis underwent a two-step procedure. All the cases were managed with a diverting loop ileostomy. Six patients underwent a standard double-stapled IPAA anastomosis, and two patients with FAP underwent a mucosectomy with a manual IPAA anastomosis. The mean operative time was 187 min, and the mean blood loss was 46 ml. There were two postoperative complications. One patient presented with an early small bowel obstruction due to an internal hernia, which required reoperation. The other complication was a wound infection. The mean return to oral intake was 1.5 days, and the mean length of hospital stay was 3.4 days. CONCLUSION: Although this was not a comparative study and although sample size imposed limitations, with this preliminary data, we conclude that the laparoscopic approach to UC and FAP at our institution is safe, feasible, and effective. However, to achieve the benefits in postoperative outcome, this procedure should be performed only by experienced laparoscopic surgeons.

Nonmuscle myosin heavy chain-B expression in balloon-dilated and stented arteries: a study in the atherosclerotic Yucatan micropig.

BACKGROUND: Restenosis after balloon angioplasty is in part due to remodelling, whereas restenosis after stenting is entirely due to neointima formation. Nonmuscle myosin heavy chain-B (NMMHC-B) is expressed by vascular smooth muscle cells and because of its overexpression in restenotic lesions after balloon angioplasty, NMMHC-B is proposed as a potential therapeutic target. Because the mechanisms underlying restenosis after balloon angioplasty or after stenting are different we hypothesised that the expression of NMMHC-B would differ in balloon-dilated versus stented arteries. METHODS: To study the localisation and time course of expression of NMMHC-B, we performed stenting or balloon dilation in peripheral arteries of 16 atherosclerotic Yucatan micropigs and used serial intravascular ultrasound (IVUS) and angiography to measure geometric dimensions following balloon angioplasty or stenting. In situ hybridisation techniques were used to detect NMMHC-B mRNA. 5'-bromo-2'-deoxyuridine (BrdU) was administered to detect proliferating cells. By counting the number of silver grains in the different layers of the artery, we could compare the amount of expression at the different time points between the groups. RESULTS: In intima and media, NMMHC-B expression increased after balloon dilation and stenting and peaked at 7 days. In stented arteries, the expression of NMMHC-B remained high for up to 42 days after injury, whereas in balloon-dilated arteries it had normalised. In the adventitia of balloon-dilated arteries, but not of stented arteries, NMMHC-B expression peaked at 7 days. NMMHC-B expression was not limited to proliferating cells. CONCLUSION: NMMHC-B is expressed near sites of active repair after arterial injury, but not limited to proliferating cells. The different pattern of NMMHC-B expression after balloon dilation compared with stenting may be related to arterial remodelling, because stented arteries that do not remodel lack this conspicuous adventitial expression at 7 days.

Differential cell cycle progression patterns of infiltrating leukocytes and resident cells after balloon injury of the rat carotid artery.

The heterogeneous nature of the cell populations involved in vascular repair remains a major hurdle for the assessment of the cellular events that take place in injured arteries. The present experiments were designed to estimate the proportions and cell cycle progression of infiltrating leukocytes versus resident vascular cells after balloon injury of the rat common carotid artery. After tissue disaggregation, cell suspension samples from each artery were analyzed by flow cytometry. Cells were stained with anti-CD45 or anti-alpha-smooth muscle actin antibodies to identify leukocytes and smooth muscle cells, respectively. A day after injury, a 12-fold increase in CD45+ leukocytes was found. Double labeling with CD45 and CD-3, ED-1, or granulocyte markers revealed that most infiltrating cells were monocytes and granulocytes. Approximately 14% of infiltrating leukocytes were found to enter apoptosis at day 1, and 17% entered S phase at day 3. In contrast, the highest proliferation rate of resident alpha-smooth muscle actin-positive cells was observed at day 7 (19%). The present results demonstrate that infiltrating leukocytes and resident vascular smooth muscle cells have dissimilar cell cycle profiles. Furthermore, our study demonstrates the feasibility of using flow cytometry to quantitatively determine the cell types and their relative activation state in injured arteries.

Intracoronary beta-radiation exacerbates long-term neointima formation in balloon-injured pig coronary arteries.

BACKGROUND: Long-term biological effects of ionizing radiation on coronary arteries remain poorly defined. We examined late arterial responses 6 months after balloon angioplasty and beta-radiation in normal pig coronary arteries. METHODS AND RESULTS: Coronary arteries of 25 adult pigs were randomized to receive 20 Gy (n=8) or 30 Gy (n=9) of (186)Re beta-radiation or sham radiation (n=8) immediately after balloon angioplasty. Aspirin was given daily during follow-up. The study vessels were analyzed histopathologically at 6 months. beta-Radiation decreased lumen area (20 Gy, 1.55+/-0.99 mm(2); 30 Gy, 1.03+/-0.82 mm(2); and 0 Gy, 2.05+/-0.80 mm(2); P<0.05) but not overall vessel area. The neointimal area was significantly larger within the injured segment with beta-radiation (20 Gy, 1.92+/-1.23 mm(2); 30 Gy, 1.51+/-0.97 mm(2); and 0 Gy, 0.89+/-0.31 mm(2); 0 Gy versus 20 Gy, P<0.05), and a significant increase of edge stenosis was observed with beta-radiation. Irradiated vessels also had larger thrombus areas within the neointima (30 Gy, 0.24+/-0.61 mm(2); 20 Gy, 0.98+/-1.57 mm2; and 0 Gy, 0.00+/-0.01 mm(2); P<0.05) and larger adventitial areas (20 Gy, 2.25+/-0.75 mm(2); 30 Gy, 2.38+/-0.98 mm(2); and 0 Gy, 1.23+/-0.29 mm(2); 0 Gy versus 20 or 30 Gy, P<0.05) that showed substantial collagen accumulation. CONCLUSIONS: Intracoronary beta-radiation did not inhibit neointima formation in balloon-injured normal pig coronary arteries 6 months after the interventional procedure. Unresorbed thrombus contributed to, but was not the sole component of, augmented neointima formation. Irradiated vessels demonstrated more adventitial thickening and fibrosis. These observations may have relevance for long-term clinical outcomes after intracoronary beta-radiation.

Adventitial cells do not contribute to neointimal mass after balloon angioplasty of the rat common carotid artery.

BACKGROUND: Previous studies suggest that the migration of adventitial cells into the neointima after balloon angioplasty might have an important role in vascular lesion formation. The current experiments were designed to study the migration of adventitial cells in response to mechanical injury of the rat carotid artery. METHODS AND RESULTS: Adventitial cells were stained in situ with PKH26, a fluorescent dye, after balloon angioplasty of the rat common carotid artery. Animals were killed at different time points, and tissue sections were examined under light and fluorescence microscopy. PKH26-labeled cells were detected exclusively in the adventitia. No labeled cells were present in the media or the neointima at any time point examined. A highly cellular neoadventitial layer composed of myofibroblasts exhibited an extensive proliferative response 3 days after injury over the entire adventitial circumference. CONCLUSIONS: Despite the prominent role that adventitial myofibroblasts seem to have in the postangioplasty remodeling process, they do not migrate to the medial or intimal layers in the rat carotid artery angioplasty model.

Perivascular inflammation after balloon angioplasty of porcine coronary arteries.

BACKGROUND: Inflammation has been suggested to play a role in vascular lesion formation after angioplasty. Whereas previous studies have focused on inflammatory reactions in the intima and media, less attention has been paid to adventitial and perivascular responses and their potential role in vascular remodeling. METHODS AND RESULTS: Balloon overstretch injury of porcine coronary arteries was performed with standard clinical angioplasty catheters. Vessels were examined from 0.5 hour to 14 days after injury by immunohistochemistry and in situ hybridization (ISH) for neutrophil and macrophage markers, cell adhesion molecules (P-selectin, E-selectin, and vascular cell adhesion molecule-1), and neutrophil-specific CXC chemokines (alveolar macrophage-derived neutrophil chemotactic factor [AMCF]-I/interleukin-8 and AMCF-II). Neutrophils accumulated in the adventitia surrounding the injury site from 2 hours to 3 days, followed by macrophages from 1 to 7 days after angioplasty. Inflammation was associated temporally with the expression of mRNAs encoding cell adhesion molecules and chemokines. The main inflammatory and proliferative foci were not limited to the adventitia but rather extended many millimeters away from the injured vessel throughout the surrounding adipose and myocardial tissues. CONCLUSIONS: Inflammatory responses after angioplasty of porcine coronary arteries occurred throughout the entire perivascular tissue. We hypothesize that perivascular inflammatory cells play a role in the recruitment and/or proliferation of adventitial myofibroblasts, possibly through the release of reactive oxygen species and/or cytokines, and thus contribute to vascular remodeling associated with postangioplasty restenosis.

Enhanced gene transfer to rabbit jugular veins by an adenovirus containing a cyclic RGD motif in the HI loop of the fiber knob.

Gene therapy using recombinant adenoviral vectors represents a promising therapeutic tool to prevent vein graft stenosis, the main complication of coronary artery bypass grafting. However, the low transduction efficiency of vascular smooth muscle cells and endothelial cells (EC) is a potential limitation, presumably due to the low levels of functional adenovirus receptor (coxsackie:adenovirus receptor; CAR). Designing vectors specifically targeted to alpha(v) integrins is a strategy that might overcome the poor expression of CAR in vascular smooth muscle cells and EC. RGD, a receptor-binding motif that can interact with alpha(v) integrins, was inserted into the HI loop and at the C-terminus of the adenoviral fiber protein in two separate adenovirus vectors encoding a beta-galactosidase reporter gene. Av1nBgCRGD (C-terminus) and Av1nBgHIRGD (HI loop) were evaluated in EC in culture and in jugular vein organ culture. Transduction of primary rat and rabbit EC with Av1nBgHIRGD was significantly more efficient when compared to Av1nBgCRGD or Av1nBg. Transduction of mouse, rat and rabbit jugular veins in organ culture using Av1nBg showed that adenovirus-mediated gene expression was greatest in rabbit jugular veins compared to rat and mouse veins. Av1nBgHIRGD augmented gene expression approximately four-fold in rabbit jugular veins when compared to Av1nBg. Histochemical analysis showed that numerous EC but few smooth muscle cells were transduced at all vector concentrations. A substantial number of adventitial fibroblasts were transduced only at the highest vector concentrations of Av1nBgHIRGD. These findings demonstrate that integrin-targeted vectors allow for enhanced gene delivery to veins and strengthen the viability of adenoviral-mediated gene transfer of therapeutic transgenes to human veins prior to vein grafting.

Mutagenicity and antioxidant assessment of Stachitarpheta jamaicensis (L.) Vahl.

Stachitarpheta jamaicensis (L.) Vahl. is a member of the Verbenaceae commonly used in Cuba, mainly as vermifugue and against diarrhoea. The mutagenic potential of a hydroalcohol extract of its aerial parts was assessed in vitro using the Salmonella/microsome assay and in vivo in the mouse bone marrow micronucleus test. No positive response was observed in a battery of four Salmonella typhimurium strains employed: TA 1535, TA 1537, TA 98 and TA 100, when exposed to concentrations up to 5 mg/plate, with and without mammalian metabolic activation. In the same way, no increase in the micronucleus frequency in mitotic erythropoietic tissue was observed when animals were administered the extract orally in doses of 500, 1000 and 2000 mg/kg. The extract inhibited lipid peroxidation in the rat liver microsomal fraction (IC(50) = 3.6 microg/mL) but it does not seem to be an effective.OH radical scavenger (IC(50) = 76.7 microg/mL). Noteworthy, it increased in a dose dependent way the level of revertant colonies in E. coli IC 203, a strain sensitive to oxidative mutagenesis, when assayed together with hydrogen peroxide and ferrous sulphate, which suggests a pro-oxidant action.

Inhibition of neointima formation by tranilast in pig coronary arteries after balloon angioplasty and stent implantation.

OBJECTIVES: We evaluated the effect of orally administered tranilast, N-(3,4-dimethoxycinnamoyl) anthranilic acid, on histologic and histomorphometric changes after angioplasty or stent implantation in pig coronary arteries. BACKGROUND: Tranilast, which has antikeloid and antiallergic properties and therefore may modulate the fibrotic and inflammatory tissue responses to angioplasty and stenting, has been shown to inhibit angiographic restenosis in small clinical trials. However, its effect on histomorphometric changes in coronary arteries after angioplasty and stenting is unknown. METHODS: Following initial pharmacokinetic studies in two pigs to determine desirable plasma levels of orally administered tranilast, 36 crossbred juvenile pigs were randomized to placebo or tranilast before undergoing balloon angioplasty in both the left anterior descending and left circumflex plus stent implantation in the right coronary artery. Oral tranilast was administered at 3 g/day starting 3 days before coronary injury and continued for 28 days until euthanasia. Injured vessels were harvested and sections analyzed by computer-assisted microscopic planimetry. RESULTS: In balloon-injured vessels, tranilast was associated with a 37% reduction in neointimal area normalized to fracture length (0.47 +/- 0.01 vs. 0.74 +/- 0.03 mm; p < 0.001) and a 23% reduction in adventitial area normalized to vessel size (0.43 +/- 0.02 vs. 0.56 +/- 0.03; p = 0.003). In stented arteries, neointimal area normalized to injury score was 32% lower in the tranilast-treated group compared to control (1.94 +/- 0.17 vs. 2.86 +/- 0.29; p = 0.01). CONCLUSIONS: In pig coronary arteries, tranilast was associated with a reduction in neointima formation and adventitial reaction after balloon injury. In stented vessels, tranilast was associated with a reduction in neointima formation normalized to injury score.

[An assessment of prostatic weight by ultrasound]. / Evaluación del peso prostático por ultrasonido.

OBJECTIVE: To analyze the utility of transvesical ultrasound in the estimation of prostate weight. METHODS: A study was conducted on 50 patients with symptomatic prostatism, aged 54-82 years (mean 60). All the patients had a prostate volume estimation by ultrasound 15 days before surgery using the following formulas: AP x T x Cc x 0.52 cm; AP + T + Cc + 3 mm. All patients underwent surgery for benign obstructive prostatic disease; 25 by TURP and 25 by open surgery. The prostate tissue removed was compared with the US estimation. RESULTS: AP x T x Cc x 0.52 cm was found to be the most accurate formula for prostates weighing less than 50 gm and AP + T + Cc + 3 mm the most accurate for prostates greater than 50 gm. CONCLUSIONS: Our results show that not all formulas are applicable to all prostate sizes.

Monocyte chemoattractant protein-1 expression in aortic tissues of hypertensive rats.

Monocyte chemoattractant protein-1 (MCP-1), a potent monocyte chemoattractant synthesized by vascular cells and monocytes, has been proposed to be an important mediator of inflammatory responses in the arterial vasculature. It was recently demonstrated that hypertension is associated with an inflammatory response in the arterial wall. To determine the effect of hypertension on arterial MCP-1 expression, we induced hypertension in Sprague-Dawley rats by infusing angiotensin II (0.75 mg x kg[-1] x d[-1] SC) for 7 days. Using Northern blot analysis, we detected a 3.6-fold increase in MCP-1 mRNA in the aortas of hypertensive rats. When we normalized blood pressure in angiotensin II-treated rats through oral administration of the nonspecific vasodilator hydralazine (15 mg x kg[-1] x d[-1]), aortic MCP-1 mRNA expression was significantly reduced. Similar results were obtained with a norepinephrine model of hypertension. Taken together, these data suggest that mechanical factors may be responsible in part for the upregulation of expression. Consistent with this interpretation, we found that cultured rat aortic vascular smooth muscle cells exposed to mechanical strain (20% peak deformation at 1 Hz) exhibited a marked increase in MCP-1 expression, suggesting the hemodynamic strain imparted onto arterial cells in hypertension is an important stimulus underlying this phenomenon. These results provide important insights into the in vivo regulation of MCP-1 and have potential implications for understanding the influence of hypertension on atherosclerosis.

Angiotensin II-induced hypertension increases heme oxygenase-1 expression in rat aorta.

BACKGROUND: We investigated the in vivo effects of angiotensin (Ang) II-induced hypertension on heme oxygenase (HO) mRNA and protein expression, activity, and localization in rat aortas. METHODS AND RESULTS: Infusion of Ang II (0.7 mg x kg(-1) x d(-1)) increased HO-1 mRNA levels to 169+/-31%, 251+/-47%, 339+/-26%, and 370+/-74% of the control level at 1, 3, 5, and 7 days after operation, respectively. The HO-1 protein level at 7 days was markedly upregulated, as was HO activity. Treatment with either losartan (25 mg x kg(-1) x d(-1)) or hydralazine (15 mg x kg(-1) x d(-1)), both of which prevented the Ang II-induced hypertension, blocked HO-1 mRNA upregulation. Norepinephrine infusion (2.8 mg x kg(-1) x d(-1)) produced a degree of hypertension and degree of HO-1 mRNA upregulation similar to those of Ang II infusion, which was again blocked by treatment with hydralazine (382+/-18% and 150+/-30% of the control level, respectively). Immunohistochemical analysis demonstrated that HO-1 is expressed in medial smooth muscle and adventitial cells in normotensive rat aortas, and this is markedly increased in adventitial and endothelial cells in Ang II-induced hypertensive rat aortas. In contrast, HO-2 protein expression was not changed in hypertensive rat aortas. CONCLUSIONS: These findings indicate that HO-1 is upregulated in hypertensive rat aortas, apparently by mechanisms unique to Ang II and by hemodynamic stress.

Expression of nonmuscle myosin heavy chain-B isoform in the vessel wall of porcine coronary arteries after balloon angioplasty.

Nonmuscle myosin heavy chain-B isoform (NMMHC-B) is expressed by proliferating vascular smooth muscle cells (SMCs), and its expression in primary lesions has been proposed to be predictive of restenosis after atherectomy. The present study was designed to study the time-course expression of NMMHC-B after angioplasty of porcine coronary arteries by in situ hybridization and immunohistochemistry. Domestic juvenile swine underwent percutaneous transluminal coronary angioplasty (PTCA) of the left anterior descending and circumflex coronary arteries with standard clinical angioplasty catheters. To identify proliferating cells, 5'-bromo-2'-deoxyuridine (BrdU) was administered and detected by immunohistochemistry on serial sections. Vessels were examined at 3, 7, and 14 days after balloon angioplasty, and uninjured coronary vessels were used as controls. Normal arteries showed hybridization to 35S-labeled NMMHC-B riboprobes localized mainly in the medial layer. NMMHC-B expression in the adventitia was markedly increased 3 days after balloon angioplasty. Seven and 14 days after injury, NMMHC-B mRNA-containing cells were localized in the adventitia and neointima at the arterial injury site. Cell proliferation, as indicated by BrdU staining, colocalized with NMMHC-B mRNA expression 3 and 7 days after angioplasty. These data indicate that cells proliferating in the adventitia and neointima express NMMHC-B; however, its expression is not limited to the proliferative state, since NMMHC-B mRNA was also found in quiescent SMCs of normal coronary arteries and in nonproliferating adventitial and neointimal cells 14 days after angioplasty.

p22phox mRNA expression and NADPH oxidase activity are increased in aortas from hypertensive rats.

Recent studies suggest that superoxide production by the NADPH/NADH oxidase may be involved in smooth muscle cell growth and the pathogenesis of hypertension. We previously showed that angiotensin II (Ang II) activates a p22phoxbased NADPH/NADH oxidase in cultured rat vascular smooth muscle cells and in animals made hypertensive by infusion of Ang II. To investigate the mechanism responsible for this increased oxidase activity, we examined p22phox mRNA expression in rats made hypertensive by implanting an osmotic minipump that delivered Ang II (0.7 mg/kg per day). Blood pressure began to increase 3 days after the start of Ang II infusion and remained elevated for up to 14 days. Expression of p22phox mRNA in aorta was also increased after 3 days and reached a maximum increase of 338 +/- 41% by 5 days after pump implantation compared with the value after sham operation. This increase in mRNA expression was accompanied by an increase in the content of the corresponding cytochrome (twofold) and NADPH oxidase activity (179 +/- 11% of that in sham-operated rats 5 days after pump implantation). Treatment with the antihypertensive agents losartan (25 mg/kg per day) or hydralazine (15 mg/kg per day) inhibited this upregulation of mRNA levels and activity. Furthermore, infusion of recombinant heparin-binding superoxide dismutase decreased both blood pressure and p22phox mRNA expression. In situ hybridization of aortic tissue showed that p22phox mRNA was expressed in medial smooth muscle as well as in the adventitia. These findings suggest that Ang II-induced hypertension activates the NADPH/NADH oxidase system by upregulating mRNA levels of one or several components of this oxidase system, including the p22phox, and that the NADPH/NADH oxidase system is associated with the pathology of hypertension in vivo.