Characterization of the activity of heavy metal-responsive promoters in the cyanobacterium Synechocystis PCC 6803.

Aiming at developing cyanobacterial-based biosensors for heavy metal detection, expression of heavy metal inducible genes of the cyanobacterium Synechocystis PCC 6803 was investigated by quantitative RT-PCR upon 15 minutes exposure to biologically relevant concentrations of Co2+, Zn2+, Ni2+, Cd2+, Cr6+, As3+ and As5+. The ziaA gene, which encodes a Zn2+-transporting P-type ATPase showed a markedly increased mRNA level after incubation with Cd2+ and arsenic ions, besides the expected induction by Zn2+ ions. The Co2+ efflux system-encoding gene coaT was strongly induced by Co2+ and Zn2+ ions, moderately induced by As3+ ions, and induced at a relatively low level by Cd2+ and As5+ ions. Expression of nrsB, which encodes a part of a putative Ni2+ efflux system was highly induced by Ni2+ salts and at a low extent by Co2+ and Zn2+ salts. The arsB gene, which encodes a putative arsenite-specific efflux pump was highly induced by As3+ and As5+ ions, while other metal salts provoked insignificant transcript level increase. The transcript of chrA, in spite of the high sequence similarity of its protein product with several bacterial chromate transporters, shows no induction upon Cr6+ salt exposure. We conclude that due to the largely unspecific heavy metal response of the studied genes only nrsB and arsB are potential candidates for biosensing applications for detection of Ni2+ and arsenic pollutants, respectively.

Characterisation of epitopes on barley mild mosaic virus coat protein recognised by a panel of novel monoclonal antibodies.

Barley mild mosaic virus (BaMMV), a member of the family Potyviridae, genus Bymovirus, is involved in the economically important yellow mosaic disease of winter barley in East Asia and Europe. We investigated serological properties of bacterially expressed BaMMV coat protein (CP) of a German isolate. Ten mouse monoclonal antibodies were produced using purified E. coli expressed BaMMV-CP as immunogen. The reactivity of MAbs with different strains of BaMMV was analysed by several immunological methods that are frequently used in diagnostic virology: enzyme-linked immunosorbent assay (ELISA), dot-blot, Western-blotting (WB), direct tissue blotting immunoassay (DTBIA) and immunoelectron microscopy (IEM). The amino acids involved in the formation of epitopes recognised by several MAbs were mapped by using synthetic pin-bound peptides and the localisation of epitopes in assembled virus particles was determined by electron microscope studies. MAbs V29 and M1 decorated the whole virion indicating that their epitopes 6PDPI9 and 96ITDDEK101, respectively, are exposed on the surface. The MAbs V6 and V14 both interacted with 44LPEPKM49, which seems to be accessible at only one end of the virus particle. The MAbs V6, V14, V29 and M1 detected epitopes common to a wide range of BaMMV isolates and can therefore be used effectively in routine diagnostic tests for BaMMV from barley leaves. We suggest that MAbs M1, V6, V14 and V29 are most suitable for use in TAS-ELISA, V6, V14 and V29 for Western blotting and V29 and M1 for electron microscope serology.

Prevention of deep-vein thrombosis after major spinal surgery: a comparison study of external devices.

We studied the difference in postoperative thrombotic complications after major spinal surgery between two commonly used external compression devices. Our 136 subjects were prospectively randomized to receive either thigh-high sequential pneumatic compression wraps or pneumatic foot-compression wraps. All were studied postoperatively with duplex ultrasonography and analyzed for leg swelling, the rate of thrombotic events, and overall subjective patient comfort. The rate of postoperative thrombosis was 1.5%. The one pulmonary embolism was successfully treated with heparin. One other patient had a small asymptomatic thrombus of the saphenous vein. Both subjects wore foot wraps. Subjectively, the devices were rated as being equally comfortable. We believe that external compression for thrombosis prophylaxis after major spinal surgery is effective. The particular device chosen may be driven by other factors such as cost, physician or nursing preference, and ease of application.

Renal artery angioplasty: technical results and clinical outcome in 320 patients.

OBJECTIVE: To review the results of percutaneous transluminal renal artery angioplasty (PTRA), including technical success and clinical outcome, at Mayo Clinic Rochester. DESIGN: We retrospectively reviewed our experience with 320 patients who underwent PTRA for stenosis of 396 arteries during a 14-year period. MATERIAL AND METHODS: We reviewed medical records and angiograms of patients who underwent PTRA at Mayo Clinic Rochester between January 1980 and December 1993. The patients were divided into four groups, based on clinical history and angiographic appearance of the stenosing lesion: renal artery atherosclerosis (ASO group), fibromuscular dysplasia (FMD group), previous renal artery bypass or endarterectomy, and renal artery stenosis in a solitary kidney. Technical results of the PTRA were determined by evaluation of angiograms obtained before and after the procedure. Data on patient demographics, blood pressure, antihypertensive medications, and serum creatinine were recorded for the period preceding PTRA, after the procedure, and at last follow-up. RESULTS: All groups had statistically significant reductions in mean arterial pressure and antihypertensive medications after PTRA. The percentage of patients who benefited after renal artery angioplasty was 70% for patients with ASO (8.4% cured), 63% for patients with FMD (22% cured), 53.8% for patients with prior surgical revascularization (23.1% cured), and 91.7% for patients with a solitary kidney (0% cured). No significant overall change in serum creatinine level was noted after the procedure in any group. Complications were comparable to those reported in other studies. The 30-day all-cause mortality rate was 2.2% for the current study, all deaths occurring in the ASO group. CONCLUSION: PTRA rarely leads to a "cure" of renovascular hypertension but provides effective control of blood pressure and decreases the medication requirements in selected patients.

Advanced renovascular hypertension and renal insufficiency: trends in medical comorbidity and surgical approach from 1970 to 1993.

PURPOSE: The primary aims of this study were to delineate trends in medical comorbidity and surgical approach in patients with renal atherosclerosis and azotemia. METHODS: We reviewed 1643 patients undergoing renovascular surgery between 1970 and 1993. We focused on those with the most advanced kidney disease (serum creatinine > 2 mg/dl) (n = 402). Attention was focused specifically on trends in sex, age, medical risk factors, surgical technique (bypass vs endarterectomy), and outcome including eventual need for long-term dialysis. RESULTS: From 1970 to 1980, 652 patients underwent renovascular surgery, with 98 (15%) having a serum creatinine > 2 mg/dl. From 1980 to 1993, the percentage of patients with renal insufficiency increased to 31% (304 of 991) (p < 0.001). Gender distribution did not change, but median age rose from 63.5 years in the first decade to 68.0 in the past 13 years. A remarkable increase in all serious medical risk factors also occurred (first vs second decade). Another significant trend was a shift toward bilateral simultaneous transaortic endarterectomy (18% from 1980 to 1985 vs 53% from 1986 to 1993; p < 0.01), which simplified and achieved complete renal revascularization, especially in patients having multiple renal artery stenoses and those needing aortic grafting for occlusive or aneurysmal disease (56% from 1970 to 1980 vs 75% from 1980 to 1993). Patients at low risk (0 to 1 comorbid medical conditions) had a 30-day mortality rate of 5.6% compared with patients at high risk (2 to 3 comorbid conditions) (15.5%) (p = 0.016). The eventual need for long-term dialysis remained low (9%) for patients with a preoperative serum creatinine of 2 to 2.9 mg/dl compared with those with a serum creatinine greater than 3 mg/dl (35%, p < 0.01). CONCLUSIONS: In the past 20 years, there has been a remarkable increase in the medical comorbidity and extent of aortic disease in patients undergoing surgical revascularization for advanced renovascular hypertension and renal insufficiency. However, the surgical approach can be simplified and expedited by bilateral transaortic endarterectomy, and the risk of late dialysis can be reduced significantly by operating before the serum creatinine exceeds 3 mg/dl.