Confocal imaging of Pseudomonas syringae pv. phaseolicola colony development in bean reveals reduced multiplication of strains containing the genomic island PPHGI-1.

Pseudomonas syringae pv. phaseolicola is the seed borne causative agent of halo blight in the common bean Phaseolus vulgaris. Pseudomonas syringae pv. phaseolicola race 4 strain 1302A contains the avirulence gene hopAR1 (located on a 106-kb genomic island, PPHGI-1, and earlier named avrPphB), which matches resistance gene R3 in P. vulgaris cultivar Tendergreen (TG) and causes a rapid hypersensitive reaction (HR). Here, we have fluorescently labeled selected Pseudomonas syringae pv. phaseolicola 1302A and 1448A strains (with and without PPHGI-1) to enable confocal imaging of in-planta colony formation within the apoplast of resistant (TG) and susceptible (Canadian Wonder [CW]) P. vulgaris leaves. Temporal quantification of fluorescent Pseudomonas syringae pv. phaseolicola colony development correlated with in-planta bacterial multiplication (measured as CFU/ml) and is, therefore, an effective means of monitoring Pseudomonas syringae pv. phaseolicola endophytic colonization and survival in P. vulgaris. We present advances in the application of confocal microscopy for in-planta visualization of Pseudomonas syringae pv. phaseolicola colony development in the leaf mesophyll to show how the HR defense response greatly affects colony morphology and bacterial survival. Unexpectedly, the presence of PPHGI-1 was found to cause a reduction of colony development in susceptible P. vulgaris CW leaf tissue. We discuss the evolutionary consequences that the acquisition and retention of PPHGI-1 brings to Pseudomonas syringae pv. phaseolicola in planta.

Characterization of the pathogenicity of strains of Pseudomonas syringae towards cherry and plum.

Bacterial canker is a major disease of Prunus avium (cherry), Prunus domestica (plum) and other stone fruits. It is caused by pathovars within the Pseudomonas syringae species complex including P. syringae pv. morsprunorum (Psm) race 1 (R1), Psm race 2 (R2) and P. syringae pv. syringae (Pss). Psm R1 and Psm R2 were originally designated as the same pathovar; however, phylogenetic analysis revealed them to be distantly related, falling into phylogroups 3 and 1, respectively. This study characterized the pathogenicity of 18 newly genome-sequenced P. syringae strains on cherry and plum, in the field and laboratory. The field experiment confirmed that the cherry cultivar Merton Glory exhibited a broad resistance to all clades. Psm R1 contained strains with differential specificity on cherry and plum. The ability of tractable laboratory-based assays to reproduce assessments on whole trees was examined. Good correlations were achieved with assays using cut shoots or leaves, although only the cut shoot assay was able to reliably discriminate cultivar differences seen in the field. Measuring bacterial multiplication in detached leaves differentiated pathogens from nonpathogens and was therefore suitable for routine testing. In cherry leaves, symptom appearance discriminated Psm races from nonpathogens, which triggered a hypersensitive reaction. Pathogenic strains of Pss rapidly induced disease lesions in all tissues and exhibited a more necrotrophic lifestyle than hemibiotrophic Psm. This in-depth study of pathogenic interactions, identification of host resistance and optimization of laboratory assays provides a framework for future genetic dissection of host-pathogen interactions in the canker disease.

Successful total knee arthroplasty in the presence of sporotrichal arthritis.

Articular sporotrichosis, a chronic granulomatous fungal infection, is a rare entity but when present may lead to significant joint destruction. Severe knee arthrosis due to sporotrichal arthritis has traditionally been treated with arthrodesis. Total knee arthroplasty in the presence of sporotrichal arthritis has been treated with long-term suppressive antifungal agents or 1-stage exchange total knee arthroplasty. We present a case in which primary total knee arthroplasty in the presence of sporotrichal arthritis resulted in good functional outcome at 2.5 years of follow-up.

HIV-1 non-specifically stimulates production of transforming growth factor-beta 1 transfer in primary astrocytes.

HIV-1 expression in monocytes/macrophages can be controlled by transforming growth factor-beta 1 (TGF-beta 1). TGF-beta 1 is present in astrocytes surrounding HIV-1-infected monocyte/macrophages in brain tissue from patients with AIDS but not from seronegative, normal individuals. We sought to determine whether or not production of TGF-beta 1 can be directly stimulated by HIV-1 in astrocytes. Astrocytes from neonatal rat cortex grown in primary culture were exposed to HIV-1 virions for 24 h. One day later, TGF-beta 1 was measured in culture supernatants by a biological assay. HIV-1 caused 1.7-2.1-fold increase in extracellular concentration of TGF-beta 1. TGF beta 1 production also was stimulated by recombinant HIV-1 proteins gp120, p66 and p24. Gp120 labeled with fluorescein was visualized inside astrocytes and its stimulatory effect was not blocked by antibodies against rat CD4. The effect was not specific to HIV-1 and its proteins, because non-opsonized Latex particles and leucine methyl ester (LME) (known to be phagocytosed and endocytosed, respectively, by astrocytes) also stimulated TGF-beta 1 production. The effect was inhibited by two inhibitors of the phago/endocytotic pathway, chloroquine and leupeptin. These results may be relevant to the neuropathogenesis of HIV-1 infection.

Glial cell-specific mechanisms of TGF-beta 1 induction by IL-1 in cerebral cortex.

Transforming growth factor beta-1 (TGF-beta 1) immunoreactive product (IRP) has recently been detected in autopsied brains of individuals who died with central nervous system diseases and/or fever but not in normal individuals or in normal rodent brain. However, the mechanism(s) of induction of TGF-beta 1 in brain and the identity of cells expressing TGF-beta 1 need to be understood before a role, if any, for this potent pleiotropic cytokine in neuropathogenesis can be discerned. Towards this end we determined that IL-1 stimulated the production of TGF-beta 1 IRP in cells and TGF-beta 1 activity in culture fluids of all glial cells, astrocytes, microglial cells, and oligodendrocytes, derived from neonatal rat cortex and grown in cell type-enriched cultures. TGF-beta 1 production in vitro varied with the cell type and isoform of IL-1. Oligodendrocytes produced the most and astrocytes the least amount of TGF-beta 1. IL-1 alpha stimulated TGF-beta 1 production in all glial cell types, whereas IL-1 beta did not. In vivo, TGF-beta 1 IRP was detected in human tissues from cerebral frontal cortex and subcortical white matter only when interleukin-1 (IL-1) was elevated in the same tissues. Moreover, the amount of detectable TGF-beta 1 was positively correlated with the amount of detectable IL-1 (rho = 0.605; P = 0.003), as determined by morphometry. Double-labelling of cells for their phenotypic markers and expression of TGF-beta 1 indicated that all glial cells, but not neurons, expressed TGF-beta 1. IL-1 alpha and IL-1 beta IRPs were also detected in all three glial cell types, most frequently in astrocytes and least frequently in microglial cells. The cells containing both cytokine IRPs were also detected. These results indicate that TGF-beta 1 may be induced by IL-1 in all glial cells of the frontal cortex, by both autocrine and paracrine mechanisms.

Urinary excretion of vasoactive factors are correlated to sodium excretion.

BACKGROUND: The relationship between urinary vasoactive factors and sodium excretion has not been adequately addressed in humans. PROCEDURE: Excretion rates of sodium, nitrates/nitrites (NOx), cGMP, and endothelin-1 (ET-1) were measured before and after ingestion of a mixed electrolyte solution (8 oz Gatorade) while undergoing a routine cardiovascular evaluation in a sample of 51 normotensive young adults. RESULTS: Significant correlations were detected for changes in excretion between all four variables, r ranged from 0.50 to 0.86 (P < .001). Correlations were higher in African Americans than white Americans. CONCLUSIONS: The association of renal ET-1 and NO activity with sodium excretion supports the hypothesis that these factors play a role in the physiologic response to acute changes in sodium intake, particularly in African Americans.

A rapid sensitive radioimmunoassay for rhodopsin: development and application.

Antisera have been raised against unbleached chromatographically pure bovine rhodopsin. A rapid sensitive radioimmunoassay (RIA) has been developed for rhodopsin, employing [125I]rhodopsin labeled using the Bolton-Hunter reagent. Protein A-bearing Staphylococcus aureus cells are used to precipitate the immune complex. Subpicomolar amounts of rhodopsin can be determined when the RIA is performed in the dark using any of nine different detergents tested. When the RIA is performed using bleached rhodopsin, the results are dependent upon the detergent in which the assay is performed. Bleached rhodopsin is most immunologically similar to unbleached rhodopsin in the mildest detergents and less similar in harsher detergents. One and a half times more bleached rhodopsin is required to compete to the same extent as unbleached rhodopsin when the RIA is performed in digitonin. Results for other detergents are: sucrose monoester, 5.0; CHAPS, 64; sodium cholate, 91; octylglucoside, 250; Triton X-100, 430; Emulphogene, 570; Ammonyx LO approximately 14,000; CTAB, unmeasureable. Other species of rhodopsin were tested as competitive in the RIA. Pig rhodopsin is 1/100th as effective a competitor as bovine rhodopsin, rat 1/200th, and frog 1/800th.

Meniscectomy and chondromalacia of the femoral condyle.

One hundred and fifty-four knees with 161 torn menisci were examined with the arthroscope immediately before meniscectomy. The incidence of early degenerative arthritis (chondromalacia) of the femoral condyle was correlated with the age of the patient, the interval between injury and surgery, and the type of meniscal lesion. The incidence of condylar chondromalacia was significantly higher in patients over the age of thirty (p less than 0.01) and in those with a history longer than three months (p less than 0.05). Posterior horn tears were associated with the highest incidence of degenerative changes, but were also associated with a longer history and with older patients. Attention is drawn to the adverse effect of damaged menisci on condylar articular cartilage, and a plea is made for early diagnosis and removal of damaged menisci.

Comparison of iodixanol and iohexol in renal impairment.

Iodixanol (Visipaque, Nycomed, Oslo, Norway) is an iodinated contrast medium in the form of a non-ionic dimer which is iso-osmolar with plasma at all iodine concentrations. There is little evidence regarding its renal tolerance in renal impairment. We therefore undertook a prospective randomized comparison of iodixanol and the non-ionic monomer iohexol (Omnipaque, Nycomed, Oslo, Norway). The serum creatinine was measured pre- and post-angiography in a series of in-patients to establish whether there was any clinically detectable evidence of superiority of iodixanol over iohexol in this high risk group. 8/54 (15%) patients in the iodixanol group had a rise in creatinine of > 10% in the week following angiography compared with 15/48 (31%) in the iohexol group (p < 0.05). The creatinine rise was positively correlated with the dose of both contrast media. These results suggest that iodixanol may be slightly less nephrotoxic than iohexol.

A new stent-graft for transjugular intrahepatic portosystemic shunts.

The transjugular intrahepatic portosystemic shunt (TIPSS) has become an effective method of treatment for the complications of portal hypertension, however shunt dysfunction is common. Covered stent-grafts have been tested in animal models, and customized or "home-made" devices have been deployed in several institutions. We report the use of a new commercially available TIPSS stent-graft in six patients undergoing primary shunting as well as two cases of revision or secondary TIPSS. The device has proved relatively easy to handle and appears to have the technical features likely to improve primary patency. Further follow-up is required to properly assess shunt patency and re-intervention rates.

Radiation risk estimation in varicocele embolization.

Varicocele embolization is performed in healthy young men with normal life expectancy. Therefore, it is essential that the radiation risks associated with the procedure are minimized. The radiation risks associated with varicocele embolization have been estimated retrospectively from dose-area product records in a series of 41 cases and compared with a prospective series of 10 cases. Lithium fluoride dosemeters were used to measure gonad dose in the prospective series. Estimated lifetime fatal cancer risk was of the order of 0.1% in the retrospective series. A seven-fold reduction in median radiation dose was observed in the prospective series. The results indicate that with meticulous attention to technique, substantial reductions in radiation exposure can be achieved.

In vivo degradation of tungsten embolisation coils.

It has been suggested that tungsten embolisation coils in intracranial aneurysms may dissolve in situ. These coils are also used, in much larger quantities, for the occlusion of larger vessels outside the cranium. This study was performed to investigate whether tungsten embolisation coils may become degraded in vivo and to examine whether this is radiographically evident on medium-term follow-up. 10 patients who had undergone aortic stent-graft repair of an abdominal aortic aneurysm (8 male and 2 female, mean age 69.7 years) and 10 age- and sex-matched controls were studied. The study group had also received an average of 64 cm of tungsten coil either to prevent or to treat an endoleak. Whole blood, serum and urine tungsten levels were assayed. Immediate post-operative and follow-up abdominal radiographs were reviewed by two consultant vascular radiologists to detect visible changes in the coils. Whole blood, serum and urine levels of tungsten were highly and significantly elevated (p < 0.001) in the study group compared with the controls. No radiographic changes in the coils were seen at an average of 16.7 months. In conclusion, tungsten embolisation coils dissolve in humans but radiographic changes are not apparent on medium-term follow-up. The clinical significance of these findings is uncertain but long-term follow-up is needed.

Effects of race, sex, and socioeconomic status upon cardiovascular stress responsivity and recovery in youth.

Cardiovascular (CV) responsivity to and recovery from acute laboratory stressors, as derived from aggregate scores of CV functioning during and after postural change, video game challenge, social competence interview, and parent-child conflict discussion, were evaluated in 272 youths [mean age 13.5 +/- 2.6 years; 162 Blacks (77 males, 85 females), 110 Whites (60 males, 50 females)], all with a positive family history of essential hypertension. Blacks demonstrated greater systolic and diastolic blood pressure (SBP, DBP) and lower heart rate responsivity compared to Whites (all P values < 0.05). A race by neighborhood socioeconomic status (SES) interaction for SBP responsivity was also observed where low SES Whites and high SES Blacks had the greatest responsivity compared to their same race cohorts. Additionally, upper SES Whites had the lowest total peripheral resistance responsivity. For recovery, Blacks and males exhibited higher SBP during recovery compared to Whites and females, respectively. These findings extend previous studies and provide further support for the hypothesis that recovery from stress is a potentially informative component of the contribution of stress responsivity to cardiovascular disease.

Sports for the physically disabled. The 1976 Olympiad (Toronto).

The 1976 Olympiad for the Physically Disabled was the first olympiad with full competition for blind, paralyzed, and amputee athletes. More than 1,500 from 38 countries took part in wheelchair (12 events), blind (8 events), and amputee (11 events) games. Participants were classified by an international team of doctors. The athletes were accomodated in university residences with small infirmaries. A school near the games site was used as a field hospital. Rest areas were also set up. Volunteers served on the medical staff (three doctors, three nurses, three receptionists, and three physical therapists on each of two shifts per day). In addition doctors, nurses, trainers, and physical therapists rotated around various venues at the games site. Physicians treated 285 patients (184 were athletes; others were spectators) for a variety of problems, physical therapists treated 119 athletes, and trainers treated 114 athletes. Contigency plans in case of mass disaster were made but were not needed. Disabled athletes are slightly more vulnerable to stress and fatigue than able-bodied athletes. The Toronto games will probably be remembered as the turning point in the emergence of sports for the disabled from a purely rehabilitation measure to a true sporting event in its own right.

Anterior cruciate ligament insufficiency: a dynamic three-dimensional motion analysis.

An electrogoniometer, capable of measuring all six degrees of freedom of knee movement, was developed in our laboratory. This Instrumented Spatial Linkage system was then used to generate data for a three-dimensional assessment of 20 ACL deficient and 30 normal subjects during level walking. The system proved to be a viable method for describing total knee motion. We found the ACL deficient knees to have increased anterior/posterior translation and significant pattern differences compared to the controls. The results of this study may have implications in the treatment of the ACL deficient patient.

Lateral substitution for chronic isolated anterior cruciate ligament deficiency.

Thirty-five patients who had been surgically treated for major symptomatic isolated chronic anterior cruciate ligament deficiency by lateral extra-articular reconstruction alone were reviewed at an average of five years after operation. Seventy-seven per cent of patients reviewed were improved subjectively, and 83% of patients who were examined had objective evidence of only minor instability or none at follow-up. However, only a few patients had "normal" knees and many continued to have minor symptoms of instability with some restriction of activity. Most of the unsatisfactory results were in patients with significant chondral pathology at the time of reconstruction. While an extra-articular pivot-shift repair did not correct all the symptoms and signs completely, most patients were improved subjectively and objectively, and there were few complications.

The impact of arthroscopy on the management of disorders of the knee.

A study has been made of 800 consecutive arthroscopic examinations of the knee with special emphasis on the changes in management that resulted. Of 614 knees that would have been operated upon if arthroscopy had not been available, open operation was avoided in 32 per cent, a defferent operation was done or planned in 27 per cent, and there was no important change in the remaining 41 per cent. Of 186 knees that would have been treated conservatively if arthroscopy had not been available, the examination resulted in some immediate benefit to 30 per cent of the patients. There were no wound infections after arthroscopy alone, and the known incidence of incorrect interpretation was 1.4 percent.

The diagnosis of problems after meniscectomy.

The causes of persistent symptoms after meniscectomy have been assessed clinically, radiologically and arthroscopically in 174 knees. The commonest finding was early degenerative arthritis (chondromalacia) of the femoral condyle (40 per cent). Retained fragments of meniscus were less common than expected (13 per cent), and lesions of the other meniscus were rare (5 per cent). The clinical diagnosis was altered in 42 percent by arthroscopic examination. Arthroscopy was found to be a valuable technique in this group of patients with problems of diagnosis.

The results of partial arthroscopic meniscectomy in patients over 40 years of age.

The role of arthroscopic meniscectomy in middle-aged patients has not previously been evaluated. This paper reports on 73 knees in 68 patients aged over 40, all of whom were shown arthroscopically to have meniscal tears and who were felt to be suitable candidates for meniscectomy. Many of these patients had typical traumatic meniscal tears, and if no degenerative joint changes were present at the time of meniscectomy, 95 per cent of them had good or excellent results an average of two and a half years later. In those instances where degenerative joint changes were present, removal of the offending segment of torn meniscus produced 80 per cent good or excellent results over the same period of time. These facts seem important now that arthroscopy permits such precise diagnosis of meniscal tears and of joint degeneration.