Oncostatin M promotes biphasic tissue factor expression in smooth muscle cells: evidence for Erk-1/2 activation

Tissue factor (TF), a transmembrane glycoprotein, initiates the extrinsic coagulation cascade. TF is known to play a major role in mediating thrombosis and thrombotic episodes associated with the progression of atherosclerosis. Macrophages at inflammatory sites, such as atherosclerotic lesions, release numerous cytokines that are capable of modulating TF expression. This study examined the role of oncostatin M (OSM), a macrophage/ T-lymphocyte-restricted cytokine, in the expression of TF in vascular smooth muscle cells (SMCs). It is reported here that OSM stimulated a biphasic and sustained pattern of TF messenger RNA (mRNA). The effect of OSM on TF mRNA expression was regulated at the transcriptional level as determined by nuclear run-offs and transient transfection of a TF promoter-reporter gene construct. OSM-induced TF expression was regulated primarily by the transcription factor NF-kappaB. Activation of NF-kappaB by OSM did not require IkappaB-alpha degradation. Inhibition of MEK activity by U0126 prevented OSM-induced TF expression by suppressing NF-kappaB DNA binding activity as determined by gel-shift analysis. Further, inhibition of Erk-1/2 protein by antisense treatment resulted in suppression of TF mRNA expression, indicating a role for Erk-1/2 in modulating NF-kappaB DNA binding activity. These studies suggest that the induced expression of TF by OSM is primarily through the activation of NF-kappaB and that activation of NF-kappaB is regulated in part by the MEK/Erk-1/2 signal transduction pathway. This study indicates that OSM may play a key role in promoting TF expression in SMCs within atherosclerotic lesions.

Bilirubin-IXalpha and -IXbeta pigments, coproporphyrins and bile acids in meconium and stools from full-term and preterm neonates during the first month of life

Individual bilirubin pigments in the excreta were quantitated by newly developed methods. In meconium, bilirubin-IXbeta predominated, whereas bilirubin-IXgamma and -IXdelta remained undetectable. The daily excretion of bilirubin-IXalpha plus -IXbeta was 0.03-1.00 and 0.04-2.00 micromoles kg(-1) of birthweight in preterm and full-term infants, respectively. The ratio of bilirubin-IXalpha to -IXbeta in meconium was 0.25 +/- 0.34, 0.32 +/- 0.30 and 0.46 +/- 0.55 in newborns of gestational ages below 30, from 31 to 36 and above 36 wk, respectively. The predominance of bilirubin-IXbeta disappeared within the first week in those with gestational age >31 wk but more slowly in the very preterm group. The ratio of monoconjugated to diconjugated bilirubin-IXalpha was 4 to 5 in full-term infants, whereas this ratio was only reached after 1 mo in preterm infants. The ratio of glucuronide or glucoside to xyloside varied widely, independent of gestational age. No correlation between faecal UCB-IXalpha and beta-glucuronidase was observed. The daily coproporphyrin excretion fell from a median of 500 microg on day 1 to below 20 microg from day 7 onwards; this decrease correlated with that of bilirubin-IXbeta. The daily 3alpha-hydroxylated bile acid loss in the excreta was two- to fivefold higher than in the adult; this, together with the higher neonatal serum levels (12-90 nmoles ml(-1)), indicates an immature intestinal reabsorption and an enhanced bile acid synthesis.

CONCLUSION

Both zinc coproporphyrin and bilirubin-lXbeta are characteristic compounds of human meconium, diconjugated bilirubin-IXalpha is low or absent in meconium of very preterm infants, and faecal and serum bile acids are high.

Determination of pesticide residues in fruits and vegetables in Islamabad market

Pesticide residues in fruits and vegetable from Islamabad market, Pakistan were determined by GLC using Perkin Elmer Autosystem equipped with 63NECD and capillary column. Dimethoate was determined in the quantity of 0.032 mg kg-1 in apple, 0.110 mg kg-1 in banana, 0.004 mg kg-1 in brinjal, 1.80 mg kg-1 in cauliflower and 0.13 mg kg-1 in arvi, fenvalerate 0.010 mg kg-1 in apple and chlorpyrifos 0.004 mg kg-1 in brinjal. The importance of these pesticide residues with reference to human health is also briefly discussed.

Induction of the urokinase plasminogen activator system by oncostatin M promotes endothelial migration

Oncostatin M (OSM) is an inflammatory cytokine produced by activated macrophages and T-lymphocytes. We have previously demonstrated that OSM-induced endothelial cell migration, unlike endothelial cell proliferation and spindle formation, is independent of basic fibroblast growth factor expression (Wijelath et al. [1997] J. Cell. Sci. 110:871-879). To better understand the mechanism of OSM-induced endothelial cell migration, this study examined the potential role of the plasminogen activator system in promoting OSM mediated endothelial cell migration. OSM stimulated increased mRNA levels of urokinase-plasminogen activator (uPA) and urokinase-plasminogen activator receptor (uPAR) in a time and dose-dependent manner. Transcriptional run-off and mRNA stability analysis demonstrated that the increase in uPA and uPAR mRNA levels was due to both increased gene transcription and mRNA stability. The increase in mRNA correlated with increased protein levels of both uPA and uPAR. This increase was reflected in elevated levels of membrane-bound plasmin activity. OSM-induced endothelial cell migration was only partially dependent on plasmin activity since incubating endothelial cells without plasminogen or, in the presence of aprotinin, resulted in suppression of endothelial cell migration, indicating that OSM promoted endothelial cell migration through both a plasmin-dependent and -independent mechanism. Our results imply a role for OSM in promoting endothelial cell migration via a plasmin-dependent pathway and a uPAR-mediated pathway. Together, these and other recent studies support a role for OSM in modulating the different phases of angiogenesis.

Endoscopic plantar fasciotomy: a retrospective analysis of results in 53 patients

This retrospective study analyzes satisfaction of patients who had undergone an isolated endoscopic plantar fasciotomy (EPF) between January 1994 and January 1997. A subjective survey was completed and returned by 53 patients (a total of 69 feet), and a chart review was performed to determine final outcome. Postoperative follow-up averaged 7.2 months (range, 4-42 months). Postoperative pain levels were scored on a 7-point scale at 1 week, 1 month, and 6 months. Forty-three patients (81.1%) were satisfied with the EPF procedure and 10 patients (18.9%) were unsatisfied.

Secondary pulmonary hypertension does not adversely affect outcome after single lung transplantation

OBJECTIVE

Primary and secondary pulmonary hypertension have been associated with poor outcomes after single lung transplantation. Some groups advocate double lung transplantation and the routine use of cardiopulmonary bypass during transplantation in this population. However, the optimal procedure for these patients remains controversial. The goal of our study was to determine the safety of single lung transplantation without cardiopulmonary bypass in patients with secondary pulmonary hypertension.

METHODS

We retrospectively reviewed 76 consecutive patients with pulmonary parenchymal disease who underwent single lung transplantation from 1992 to 1998. Recipients were stratified according to preoperative mean pulmonary artery pressure. Secondary pulmonary hypertension was defined as parenchymal lung disease with a preoperative mean pulmonary artery pressure of 30 mm Hg or more. Patients with primary pulmonary hypertension or Eisenmenger's syndrome were excluded from analysis.

RESULTS

Eighteen of 76 patients had secondary pulmonary hypertension. No patient with secondary pulmonary hypertension required cardiopulmonary bypass, whereas 1 patient without pulmonary hypertension required bypass. After the operation, no significant differences were seen in lung injury as measured by chest radiograph score and PaO(2)/FIO(2) ratio, the requirement for inhaled nitric oxide, the length of mechanical ventilation, the intensive care unit or hospital length of stay, and 30-day survival. There were no differences in the forced expiratory volume in 1 second or 6-minute walk at 1 year, or the incidence of rejection, infection, or bronchiolitis obliterans syndrome greater than grade 2. Survival at 1, 2, and 4 years after transplantation was 86%, 79%, and 65%, respectively, in the low pulmonary artery pressure group and 81%, 81%, and 61%, respectively, in the group with secondary pulmonary hypertension (P >.2).

CONCLUSION

We found that patients with pulmonary parenchymal disease and concomitant secondary pulmonary hypertension had successful outcomes as measured by early and late allograft function and appear to have acceptable long-term survival after single lung transplantation. Our results do not support the routine use of cardiopulmonary bypass or double lung transplantation for patients with this disorder.

Hypocalvaria associated with intrauterine growth retardation, facial dysmorphism, congenital heart disease and camptomelia

We report an Omani child from an inbred family with a combination of hypocalvaria, intrauterine growth retardation, craniofacial disproportion, partial synostosis of the right coronal suture and a small mandible associated with congenital heart defect and bowing of the limbs. A literature search failed to reveal a similar case.

Generation and characterization of human smooth muscle cell lines derived from atherosclerotic plaque

The study of atherogenesis in humans has been restricted by the limited availability and brief in vitro life span of plaque smooth muscle cells (SMCs). We describe plaque SMC lines with extended life spans generated by the expression of the human papillomavirus (HPV)-16 E6 and E7 genes, which has been shown to extend the life span of normal adult human aortic SMCs. Resulting cell lines (pdSMC1A and 2) demonstrated at least 10-fold increases in life span; pdSMC1A became immortal. The SMC identity of both pdSMC lines was confirmed by SM22 mRNA expression. pdSMC2 were generally diploid but with various structural and numerical alterations; pdSMC1A demonstrated several chromosomal abnormalities, most commonly -Y, +7, -13, anomalies previously reported in both primary pdSMCs and atherosclerotic tissue. Confluent pdSMC2 appeared grossly similar to HPV-16 E6/E7-expressing normal adult aortic SMCs (AASMCs), exhibiting typical SMC morphology/growth patterns; pdSMC1A displayed irregular cell shape/organization with numerous mitotic figures. Dedifferentiation to a synthetic/proliferative phenotype has been hypothesized as a critical step in atherogenesis, because rat neonatal SMCs and adult intimal SMCs exhibit similar gene expression patterns. To confirm that our pdSMC lines likewise express this apparent plaque phenotype, osteopontin, platelet-derived growth factor B, and elastin mRNA levels were determined in pdSMC1A, pdSMC2, and AASMCs. However, no significant increases in osteopontin or platelet-derived growth factor B expression levels were observed in either pdSMC compared with AASMCs. pdSMC2 alone expressed high levels of elastin mRNA. Lower levels of SM22 mRNA in pdSMC1A suggested greater dedifferentiation and/or additional population doublings in pdSMC1A relative to pdSMC2. Both pdSMC lines (particularly 1A) demonstrated high message levels for matrix Gla protein, previously reported to be highly expressed by human neointimal SMCs in vitro. These results describe 2 novel plaque cell lines exhibiting various features of plaque SMC biology; pdSMC2 may represent an earlier plaque SMC phenotype, whereas pdSMC1A may be representative of cells comprising an advanced atherosclerotic lesion.

Cardiovascular surgery in the elderly

The elderly segment of the population is increasing rapidly, and surgeons are more frequently being requested to operate on this group of patients. A number of reports suggest that elderly patients have a significantly higher incidence of operative mortality and 30-day hospital mortality as compared with younger patients. Elderly patients also had a significantly higher increased incidence of complications, such as renal failure, prolonged ventilation, and incidence of strokes and postoperative cardiac arrest. Regarding coronary artery disease, elderly patients are more acutely sick on admission, are more likely to have triple-vessel disease, more likely have comorbid disease, and are usually less likely to receive an internal mammary artery graft. The presence of valvular disorders with concomitant coronary disease (especially mitral ischemic related valve disease) increases operative time, morbidity, and mortality. Efforts must continue to be made to gather data on outcomes of cardiac surgery in the elderly. Consideration must be given to modify the operative approach that minimizes cardiopulmonary bypass time, mitigates the multisystem organ injury associated with cardiopulmonary bypass, and decreases the likelihood of embolization from the ascending aorta. Future efforts must be made to develop measures to decrease the complications rate identified in elderly patients.

Snake bite experience at Pakistan Institute of Medical Sciences

We reviewed 40 cases of snake bite seen from January, 1996 to December, 1996. Most of the cases survived uneventfully but many developed complications which were either haematologic, (23 patients) or neurological (5 patients). Appropriate treatment was offered in every case. Polyvalent antisnake venom was administered to 30 patients (75%). Premedication used was steroids and antihistamines to prevent anaphylactic reactions. Antifibrinolytic therapy (tranxemic acid) was given to every bleeding patient. The species of offending snake could be recognized in one patient while in all others, it was not possible due to night time incidence and poor description by the patient.

The clinical significance of flow cytometry crossmatching in heart transplantation

BACKGROUND

Flow cytometry crossmatching is more sensitive than cytotoxic methods in identifying preformed antibodies to donor alloantigens. However, the significance of a positive flow crossmatch remains unknown for a recipient of a heart transplant who has a negative anti-human globulin crossmatch.

METHODS

Flow crossmatching was performed retrospectively for 92 recipients of a primary cardiac allograft who underwent transplantation with a negative AHG crossmatch.

RESULTS

Forty-six patients were flow crossmatch-positive for alloantibody: 20 were positive on both T and B lymphocytes, 12 were positive only on B lymphocytes, and 13 were positive only on T lymphocytes. Eleven had autoantibody invalidating the flow crossmatch with donor cells. Thirty-six patients had negative flow crossmatch. A significantly higher incidence of graft dysfunction with vascular rejection by 6 months was found for patients who had a positive flow crossmatch on B lymphocytes. This group also had an increased incidence of mortality within this same period. Patients who were flow crossmatch-positive on T and B lymphocytes were more likely to experience greater than two episodes of treated cellular rejection within the first 6 months. Flow crossmatch-positive patients stayed longer in the hospital in comparison to the other two groups, although the increases were not statistically significant. There were no differences between groups with regard to time to first rejection, absence of rejection episodes, episodes of decreased cardiac index (<2.3 L/m2), depressed left and right ventricular ejection fraction, or development of transplant atherosclerosis.

CONCLUSION

A positive flow crossmatch identified a subset of patients who are predisposed to development of vascular rejection or are more likely to have frequent cellular rejection.

Pattern of tuberculosis in general practice

An audit of 690 cases of tuberculosis out of 46,276 patients seen during the last 25 years in a busy general practice is reported. Of the 690 cases, 67% were pulmonary, 33% extra-pulmonary TB. Modes of both types of tuberculosis are described and the reason for increased incidence of extra-pulmonary tuberculosis are discussed.

Bioresorbable microporous stents deliver recombinant adenovirus gene transfer vectors to the arterial wall

The use of intravascular stents as an adjunct for percutaneous transluminal revascularization is limited by two principal factors, acute thrombosis and neointimal proliferation, resulting in restenosis. To overcome these limitations, we have investigated the potential of microporous bioresorbable polymer stents formed from poly(L-lactic acid) (PLLA)/poly(epsilon-caprolactone) (PCL) blends to function both to provide mechanical support and as reservoirs for local delivery of therapeutic molecules and particles to the vessel wall. Tubular PLLA/PCL stents were fabricated by the flotation-precipitation method, and helical stents were produced by a casting/winding technique. Hybrid structures in which a tubular sheath is deposited on a helical skeleton were also generated. Using a two-stage solvent swelling technique, polyethylene oxide has been incorporated into these stents to improve hydrophilicity and water uptake, and to facilitate the ability of these devices to function as drug carriers. Stents modified in this manner retain axial and radial mechanical strength sufficient to stabilize the vessel wall against elastic recoil caused by vasoconstrictive and mechanical forces. Because of the potential of direct gene transfer into the vessel wall to ameliorate thrombosis and neointimal proliferation, we have investigated the capacity of these polymer stents to function in the delivery of recombinant adenovirus vectors to the vessel wall. In vitro, virus stock was observed to readily absorb into, and elute from these devices in an infectious form, with suitable kinetics. Successful gene transfer and expression has been demonstrated following implantation of polymer stents impregnated with a recombinant adenovirus carrying a nuclear-localizing betaGal reporter gene into rabbit carotid arteries. These studies suggest that surface-modified polymer stents may ultimately be useful adjunctive devices for both mechanical support and gene transfer during percutaneous transluminal revascularization.

Prospective trial of catheter irrigation and muscle flaps for sternal wound infection

BACKGROUND

Sternal wound infection is a relatively rare but potentially devastating complication of open heart operations. The most common treatments after debridement are rewiring with antibiotic irrigation and muscle flaps. Here we present the results of a prospective trial to determine the appropriate roles of closed-chest catheter irrigation and muscle flap closure for sternotomy infection and to assess the effect of internal mammary artery bypass grafting on the outcome of each treatment modality.

METHODS

Between 1990 and 1994, 5,658 sternotomies were performed at the University of Washington Medical Center. Sternal dehiscence occurred in 43 patients, 25 of whom had infection (overall incidence, 0.44%). Because of the infrequency of this complication, a prospective, randomized trial was developed in which the initial approach to sternal dehiscence was rewiring and catheter irrigation. Muscle flaps were used as the primary treatment if the sternum could not be restabilized or as secondary treatment if catheter irrigation failed. Wound resolution, length of hospital stay, and complications were evaluated.

RESULTS

Sterile dehiscences were successfully closed with irrigation in 17 of 18 patients; the other patient required flap closure. Of the 25 patients with infection, 19 had irrigation and 6, closure with flaps primarily. In the group of infected patients, 17 of the 19 who received irrigation also had internal mammary artery bypass grafting. Irrigation failed in 15 (88.2%) of these 17 patients, and salvage was accomplished with muscle flap closure. All 6 patients with infection who were closed primarily with muscle flaps had a successful outcome. Hospitalization averaged 10.2 days when muscle flaps were used primarily and 14.3 additional days for unsuccessful irrigation. When irrigation was successful, the hospital stay averaged 11.2 days.

CONCLUSIONS

Catheter irrigation should be reserved for patients without infection or patients with infection but without internal mammary artery bypass grafts in whom dehiscence occurs less than 1 month after sternotomy. All others should have closure with muscle flaps.

Donor left ventricular hypertrophy increases risk for early graft failure

A review of factors contributing to early mortality after cardiac transplantation revealed that up to 25% of deaths were due to primary graft dysfunction unrelated to rejection or infection. In light of this finding, evaluation of a donor heart with regard to its suitability for transplantation takes on added importance. In an effort to screen the suitability of donor hearts in the region covered by the Northwest Organ Procurement Agency (USA), all donors are evaluated by two-dimensional transthoracic echocardiography as part of the initial evaluation. A total of 110 donor echocardiograms were reviewed and an attempt was made to correlate the 30-day outcome with the parameters measured. An unexpected finding was that the presence of left ventricular hypertrophy in the donor heart was associated with an increase in the incidence of donor heart dysfunction compared with donors with normal echocardiographic profiles (33% vs 3%, P = 0.007).

Corticosteroid use and abuse by medical practitioners for arthritis and related disorders in Pakistan

A total of 256 consecutive patients attending our out-patient clinic in Islamabad, Pakistan, with complaints of pain in or around the joints were evaluated for use of corticosteroids prescribed by medical practitioners they had seen earlier. The appropriateness of such prescriptions and their consequent effects were assessed. Of the 256 patients, 110 (i.e. 42.5%) were identified as steroid users; some of them were suffering from conditions known to be unresponsive to this form of therapy. One hundred and one of the 256 patients had rheumatoid arthritis and 67% of these had been using steroids, mostly in an irrational manner. The general practitioners and consultants (all non-rheumatologists) were responsible for the majority of steroid prescriptions. Steroid side-effects were observed in 42/110 (38.2%) cases. This prevalent practice in Pakistan is a reflection of the state of affairs in developing countries, and indicates a need for improvement and better regulation of health care in such countries.

Blood ionized magnesium concentrations during cardiopulmonary bypass and their correlation with other circulating cations

BACKGROUND AND AIM

The recent introduction of new measurement technology (using ion specific electrodes) makes intraoperative evaluation of blood ionized magnesium (Mg2+, or iMg)--the bioactive fraction of circulation magnesium--possible. The goals of this study were: (1) to examine the longitudinal pattern(s) of change in blood iMg during cardiopulmonary bypass (CPB); and (2) to determine the relationship of iMg to Ca2+ (iCa), K, pH, Na, and hematocrit (Hct) during CPB.

METHODS

Blood was collected serially before, during, and after CPB on 30 patients undergoing elective coronary artery bypass graft procedures and the iMg was measured with an AVL Scientific Corp., model 988-4 instrument.

RESULTS

Overall, 73% of iMg results were abnormally low, 50% during CPB. Some cases had both hypo- and hyperionized magnesemic episodes. There were low iCa during CPB in 97% of cases. Using Spearman's rank order correlations and p < 0.05, iMg and K were directly correlated before, during, and after bypass, suggesting their parallel movement between tissue and blood. iMg and iCa were directly correlated before, and inversely correlated after, CPB, but unassociated during bypass. iMg and Na were inversely correlated after bypass in all cases. iMg was inversely correlated to pH and positively correlated to Hct during CPB only, and only in patients with concurrent association of iMg and iCa.

CONCLUSIONS

Blood iMg depletion occurs frequently in CPB patients. iMg changes are not readily predictable. The association of intraoperative iMg depletion with postsurgical atrial fibrillation--reported to have a hypomagnesemic connection- should be investigated.