Diversity of Xanthomonas campestris Isolates from Symptomatic Crucifers in New York State.

To assess the diversity of Xanthomonas campestris spp. infecting crucifers in New York, 154 isolates were collected over 10 years across the state. The goal was to determine if isolates of the pathogen were overwintering in New York and serving as primary inoculum in subsequent years, or if novel isolates were entering the state each year. Pure cultures of isolates were characterized using multilocus sequence analysis (MLSA), a greenhouse pathogenicity assay, repetitive element-polymerase chain reaction (Rep-PCR) using the BOX-A1R primer, and enzyme-linked immunosorbent assay. The MLSA scheme proved to be more efficient than Rep-PCR for a large sample population and for comparison with global isolates. X. campestris isolated from crucifers in New York comprised of X. campestris pv. campestris and X. campestris pv. raphani, with X. campestris pv. raphani being predominately isolated from transplants. Evidence for unique haplotypes persisting on the same farm for several years due to improper seedbed rotations was documented in addition to novel haplotypes being spread throughout states through infected transplants and seed. Rep-PCR confirmed the high diversity of X. campestris and was used to generate 15 unique fingerprint patterns from isolates collected in the first 5 years. A worldwide comparison of isolates suggests that the X. campestris pv. campestris population appears to be very homogenous with dominant haplotypes persisting for extended periods and being globally disseminated.

Differential effect of Huntington's and Parkinson's diseases in programming motor sequences of varied lengths.

BACKGROUND: Parkinson's disease (PD) and Huntington's disease (HD) patients have difficulties executing sequential movements. Attention control and short-term memory probably play an important role in programming sequential movements. To investigate the contribution of these cognitive factors to programming and executing visuomotor sequences in HD and PD patients a computerized version of the Corsi Block Tapping-Test was employed. METHODS: the performance of 11 patients with early stage PD, 11 HD patients with borderline to mild caudate atrophy and 20 healthy subjects was compared. The task was a reaction time task where targets were illuminated in groups of sequences increasing from 2 items to 5 items. Subjects reproduced the sequence (pressing the illuminated target) in the same order of appearance. Reaction Times and movement times were recorded. RESULTS: PD patients had increasing difficulties in programming and executing series greater than three components. HD patients did not differ significantly from the controls, although they showed a tendency to lose accuracy in the longer series. Both patient groups did not differ in their attention span. CONCLUSIONS: In PD although the spatial information may be well stored, they have difficulty accessing it when their attention is overloaded, leading to poor encoding and slow information processing. This process interferes with programming and execution of movement sequences. HD patients in the early stages of the illness seem to have more attention resources than PD patients, so that they start to show more problems in executing visuomotor sequences with longer movement sequences than PD patients.

Assessment of the hemodynamic response to acetyl-strophanthidin by Doppler echocardiography in normal subjects and in those with coronary artery disease or idiopathic dilated cardiomyopathy.

The effect of acetyl-strophanthidin, a rapidly acting digitalis-like drug, was measured on peak flow velocity, stroke distance (an index of stroke volume) and minute distance (an index of cardiac output), determined by Doppler echocardiography in 21 subjects with a wide range of left ventricular ejection fractions (12 to 89%, average 47%). For the total study group, peak flow velocity increased from 99 +/- 10 to 110 +/- 13 cm/s (p less than 0.01), and stroke distance increased from 15.1 +/- 3.2 to 16.8 +/- 3.1 cm (p less than 0.01). Minute distance remained unchanged: 1,093 +/- 168 cm before and 1,129 +/- 187 cm after acetyl-strophanthidin (difference not significant). Improvement in Doppler parameters of forward blood flow was significantly (p less than 0.001) greater in subjects with left ventricular ejection fractions less than 60% (+17% for peak flow velocity, +22% for stroke distance and +15% for minute distance) than those with left ventricular ejection fractions greater than or equal to 60% (+4% for peak flow velocity, +2% for stroke distance and -8% for minute distance). These data suggest that Doppler echocardiography is a useful method to assess the efficacy of acute digitalis administration in improving forward blood flow.

Local complications associated with indwelling Swan-Ganz catheters: autopsy study of 36 cases.

Thirty-six hearts of patients who died with indwelling Swan-Ganz catheters in place were prospectively examined to assess the incidence and extent of localized lesions in the right side of the heart. Bland mural thrombosis in the superior vena cava, the right atrium and the pulmonary artery was found in 22 of 36 cases (61%). Patients with catheter periods greater than 2 days had a greater incidence and extent of bland mural thrombosis (79%) than patients with short-term catheterization (41%, p less than 0.01). Anticoagulation had no influence on bland mural thrombosis. Valvular hemorrhage occurred in 31% and aseptic valvular vegetations in 8% of the hearts. No case of infective endocarditis was found. Four of 36 cases (11%) had evidence of pulmonary infarction that appeared to be unrelated to the lesions in the right side of the heart. Endocardial lesions were common complications of indwelling Swan-Ganz catheters but had no significant impact on the clinical courses of the patients.

Frequency of success and complications of coronary angioplasty of a stenosis at the ostium of a branch vessel.

The authors of this study hypothesized that percutaneous transluminal coronary angioplasty of a stenosis at the ostium of a branch vessel, whether isolated or associated with a bifurcation stenosis, was associated with reduced procedural success and increased in-hospital complications. One hundred six patients with 119 ostial branch stenoses were compared with 1,168 patients who underwent angioplasty of nonostial branch stenoses. An ostial branch stenosis was defined as a stenosis in the proximal 3 mm of a major branch vessel (diagonal [n = 58], posterior descending [n = 21], obtuse marginal [n = 34] and intermediate [n = 6]). The ostial branch stenosis was isolated in 61% of the patients and associated with a bifurcation stenosis in 39%. Despite a balloon to artery ratio of 1.05:1, angiographic success was 74% of ostial branch stenoses versus 91% of nonostial stenoses (p less than 0.01). Furthermore, angioplasty of ostial branch stenoses resulted in a complication rate of 13 versus 5% for angioplasty of nonostial branch stenoses (p less than 0.01). Therefore, angioplasty of ostial branch stenoses results in decreased procedural success and significant residual stenosis despite adequate balloon sizing, suggesting arterial elastic recoil and a significant increase in complications.

Value of transesophageal echocardiography as an adjunct to transthoracic echocardiography in evaluation of native and prosthetic valve endocarditis.

To determine if transesophageal echocardiography provides better visualization of valvular vegetations than transthoracic echocardiography, we used both methods to evaluate 24 consecutive patients (mean age, 54 years; 15 female patients and nine male patients) referred for symptoms suggestive of infectious endocarditis. Ten of the 24 patients had one or more valvular prostheses. Echocardiograms were classified as positive or negative based on visualization of valvular vegetations or abscesses. Of ten patients with a final diagnosis of infectious endocarditis on extended follow-up, transthoracic echocardiography was positive in five patients. Transesophageal echocardiography not only yielded abnormal findings in all ten of these patients, but also revealed additional information in four of the five patients with abnormal transthoracic echocardiographic examinations. Among the 14 patients who, on subsequent follow-up, were found not to have infectious endocarditis, transthoracic echocardiography was normal in 13 and falsely abnormal in one. Transesophageal echocardiography revealed no evidence of infectious endocarditis in any of these patients. The ten patients who were determined to have infectious endocarditis all had positive blood cultures and no alternative cause for their clinical presentation; in seven patients in this group who underwent operative or postmortem evaluation, infectious endocarditis was confirmed. All patients without infectious endocarditis were demonstrated to have other causes for their clinical presentation. We conclude that transesophageal echocardiography is a highly valuable test in the work-up of patients with suspected infectious endocarditis, especially those patients with inconclusive or normal transthoracic echocardiograms. In addition, transesophageal echocardiography may be of benefit to patients with previously documented infectious endocarditis and a complicated clinical course in whom additional cardiac lesions are suspected but not demonstrated by transthoracic echocardiography.

Motor learning by imagery is differentially affected in Parkinson's and Huntington's diseases.

Studies of motor imagery and motor learning have thus far been concerned only with its effects on healthy subjects. Therefore, in order to investigate the possible involvement of the basal ganglia, the effectiveness of motor imagery in the acquisition of motor constants in a graphomotor trajectorial learning task was examined in 11 non-demented mildly affected Huntington's disease (HD) patients and 12 non-demented Parkinson's disease (PD) patients. The patients received, after baseline, 10 min of motor imagery training, followed by a motor practice phase. Additionally, a test battery for visual imagery abilities was administered in order to investigate possible relations between visual and motor imagery. The results showed that imagery training alone enabled the HD patients to achieve a significant approach to movement isochrony, whereas the PD patients showed no marked improvements, either with motor imagery or with motor practice. Furthermore, the PD patients had more difficulties than the HD patients in solving the visual imagery tasks. Subsequent correlational analysis revealed significant relationships between the degree of caudate atrophy in the HD patients and their performance in the visual imagery tasks. However, there were no substantial correlations between the performance on the visual imagery tasks and the improvement of motor performance through motor imagery, which indicates that visual and motor imagery are independent processes. It is suggested that the dopaminergic input to the basal ganglia plays an important role in the translation of motor representations into motor performance, whereas the caudate nucleus atrophy of the HD patients does not seem to affect motor imagery, but only the visual imagery process. Furthermore, the deficits found in PD patients might also be related to their limited attentional resources and difficulties in employing predictive motor strategies.

Transesophageal echocardiography in patients with mechanical circulatory assistance.

Transesophageal echocardiography was used to assess myocardial function and to detect complications after mechanical circulatory support for 8 patients with cardiogenic shock. In 3 of 8 patients, serial transesophageal echocardiography documented improvement of systolic ventricular function, and it was possible to wean these 3 patients from the ventricular assist device. In all patients, transesophageal echocardiography added clinically important information including the extent of left and right ventricular dysfunction (6 patients), presence of atrial or ventricular thrombus (5 patients), presence of pericardial effusion or clot (2 patients), and verification of the position of the intravascular device (1 patient). Thus, transesophageal echocardiography may provide clinically useful information regarding both the underlying cardiac disease and potential complications from the mechanical circulatory assistance.

Normal striatal glucose consumption in two patients with benign hereditary chorea as measured by positron emission tomography.

Positron emission tomography (PET) with [18F]-2-fluoro-2-deoxy-D-glucose (FDG) was used to investigate the regional cerebral metabolic rate of glucose consumption (rCMRGlc) in two patients with benign hereditary chorea (BHC) and 21 normal subjects. Relative and absolute values of cerebellar, striatal, thalamic, and cortical rCMRGlc were within normal limits for both patients with BHC, indicating that the choreic movement disorder encountered in these two patients was not caused by a decrease of energy metabolism in the striatum such as that found regularly in most patients with other forms of chorea (e.g. Huntington's and Wilson's disease).

Striatal glucose consumption in chorea-free subjects at risk of Huntington's disease.

Controversial data have been reported with regard to the diagnostic value of the positron emission tomographic (PET) measurement of striatal glucose consumption (rCMRGlc) in chorea-free subjects at risk of Huntington's disease (HD). For further clarification of this issue we measured striatal and cerebellar rCMRGlc in 27 chorea-free subjects at risk of HD, 20 patients with manifest HD and 20 control subjects, using PET and 18F-fluorodeoxyglucose. In 6 of the at-risk subjects cerebellar ratios of striatal rCMRGlc were decreased below the corresponding 99% confidence limit determined in the controls. This indicates that the PET measurement of rCMRGlc may, indeed, be valuable in establishing the diagnosis of incipient HD in presymptomatic at-risk subjects.

Absence of long latency reflexes to imposed finger displacements in patients with Huntington's disease.

Long latency reflexes in the electromyogram (EMG) of the first dorsal interosseus muscle were elicited by short finger displacements under isometric conditions. In all healthy subjects tested the spinal response was followed by a second involuntary component. Patients with Huntington's disease lacked the late EMG response almost completely, but exhibited a spinal component indistinguishable from that of the control group. A spinal mechanism responsible for this result is unlikely, since double stretches evoked two distinct EMG responses in these patients. Moreover, drastically reduced cortical somatosensory evoked potentials in all patients support the notion that the second EMG response seen in our motor paradigm is of supraspinal origin.

Exclusion of atrial thrombus by transesophageal echocardiography.

To determine whether transesophageal echocardiography (TEE) is useful in ruling out the presence of atrial thrombus, we performed TEE in 20 patients immediately before valve replacement or valve repair and within 3 days of an autopsy in one patient. Mitral stenosis was the predominant lesion in three patients, mitral regurgitation was seen in 11 patients, five patients had mitral prosthesis malfunction, one patient had a tricuspid prosthesis malfunction, and one patient had aortic stenosis. Eight patients were in atrial fibrillation. Four patients demonstrated spontaneous contrast in the associated atria. Nine patients were receiving oral anticoagulation. Mean left atrial diameter was 5.3 +/- 1.3 mm. TEE revealed no evidence for atrial thrombus in 18 of the 21 patients; this finding was confirmed by careful inspection of the atria including the appendages. TEE demonstrated a left atrial thrombus in two patients and a right atrial thrombus in another (confirmed at the time of surgery or at autopsy). In all cases transthoracic echocardiography was negative. Our data suggest that TEE is useful in ruling out atrial thrombus, and therefore may be a useful test preceding interventions associated with an increased risk of embolism from the atria such as cardioversion, mitral valvuloplasty, or valve replacement.

Pre- and postcentral somatosensory evoked potentials in Huntington's disease: effects of stimulus repetition rate.

We recorded frontal, central and parietal somatosensory evoked potentials (SEPs) to median nerve stimulation in 20 patients with Huntington's disease (HD) and in a group of normal controls. Two stimulus repetition rates, 1 Hz and 5 Hz, were employed. In HD patients the early cortical potentials (latency range 20-30 ms) at all 3 recording locations were replaced by a widespread, broadly configured N20-25 deflection, while later potentials at 40-80 ms did not significantly differ from those of normals. In contrast to the early P22, P27 and N30 potentials in normals, the N20-25 potential in the patients was not significantly modified by changing the stimulus repetition rate. At 40-80 ms the stimulus rate effects were similar in the patients and normals. The results show that early pre- and postcentral SEPs are both pathological in HD, while later frontal and parietal components can be totally preserved. The early N20-25 in HD is possibly a subcortical potential, seen due to unmasking in the absence of early cortical deflections.

Huntington's disease: the neuroexcitotoxin aspartate is increased in platelets and decreased in plasma.

The neural degeneration observed in the striata of patients with Huntington's disease (HD) can be reproduced by excitatory NMDA receptor agonists such as aspartate and glutamate in striatal cell cultures and in striata of vertebrates injected with these substances. Therefore, we decided to investigate the role of aspartate and glutamate in HD. Aspartate, glutamate, glutamine, and phenylalanine were measured in platelets and plasma of HD patients and age- and sex-matched healthy controls (C), using HPLC methods. In HD platelets the mean aspartate concentration was significantly (p < 0.01) increased (8.9 +/- 3.8 (SD) nmol/mg protein, n = 28) compared to C (4.6 +/- 1.4 (SD) nmol/mg protein, n = 24), whereas plasma aspartate was significantly (p < 0.01) decreased in HD (0.092 +/- 0.023 (SD) mg/dl, n = 16) versus C (0.179 +/- 0.109 (SD) mg/dl, n = 21). The increase in platelet aspartate should be a direct or indirect consequence of the dominant gene defect in HD. It might therefore be present in neurons as well, especially since platelets share many characteristics with neurons. Hence, chronically increased release of aspartate with consecutive overstimulation of postsynaptic neurons via NMDA receptors might be responsible for the damage observed in striatal target cells of corticostriatal glutamatergic and aspartatergic projection fibers in HD.

Diagnostic meaning of the urinary output of Nepsilon-methylated lysines. Investigation of healthy individuals and patients with malignant diseases, myopathies or renal failure.

In the urine of 36 healthy persons the excretion of the three Nepsilon-methylated lysines and some other basic amino acids was determined. The following average values, related to 1 g creatinine, were found: Lys(Me) 16.2 mumol, Lys(Me2) 31.2 mumol, Lys(Me3) 40.5 mumol. The 24-hour excretion in 6 adults related to 1 kg body weight, had the following average values: Lys(Me) 0.37 mumol, Lys(Me2) 0.88 mumol, Lys(Me3) 0.92 mumol. In patients with degenerative or inflammatory myopathies (6 cases) as well as with generalized tumors (7 cases) urinary output of methyllysines was not significantly altered. In a patient with extremely impaired renal function, it was found that the plasma level and the excretion pattern of the methylated lysines were unequivocally altered. Metabolic stability and renal excretion of 3H-labelled l-Lys(Me3) were investigated in man. During a 24 hour period 65 per cent of Lys(Me3) was excreted into the urine unmetabolized after intravenous injection but not more than 20 per cent after oral administration.

Impairment of temporal organization of speech in basal ganglia diseases.

Absolute and relative speech timing were examined in patients suffering from Parkinson's, Huntington's, and Wilson's disease. The task was to speak a standard sentence 10 times, first slowly, and then successively faster up to maximum rate. All patient groups had low maximal speech rates and showed decreased variability of speech rate. The duration of pauses between words was the same as in normals and the relative time structure of the test sentence was basically preserved. For comparison, two cases with nonfluent aphasia had even slower speech rates, large increases in pause duration, and major changes in relative speech timing. The results show the same type of alterations of the temporal organization of speech as those characteristic for rapid alternating limb movements in such patients. They support the view that the speech and skeletomotor systems share common neural control modes despite fundamental biomechanical differences. The common denominator between the speech and the skeletomotor disturbances in basal ganglia diseases may be the undamping and slowing of a fast central oscillator.

Role of transmitral blood flow velocity by Doppler echocardiography in the evaluation of coronary artery disease.

To determine the relation between presence and severity of coronary artery disease and diastolic filling abnormalities by Doppler echocardiography, recordings of transmitral inflow velocity were made at rest in 90 patients with coronary artery disease and 28 normals. At the time of the Doppler examination, 81 patients with coronary artery disease (90%) and 10 normals (36%) were treated with antianginal medications. No difference was found in the ratio between early (E) and late (A) diastolic filling velocity (E/A ratio) when comparing patients with greater than 70% obstruction of at least one coronary artery to age-matched normals, regardless of the presence or absence of wall motion abnormalities. The E/A ratio was 1.3 +/- 0.46 in coronary patients with normal wall motion, 1.2 +/- 0.47 in coronary patients with abnormal wall motion, and 1.3 +/- 0.53 in both samples of age-matched normals. Multivariate analysis of the relation between E/A ratio and other variables showed that heart rate (F = 24.46, p less than 0.00001) and age (F = 19.51, p less than 0.00001) were significant independent determinants of the E/A ratio, while the presence or severity of coronary artery disease, the presence of hypertension, the magnitude of wall motion abnormalities, and end-diastolic dimension by echocardiography were not. These data suggest that transmitral inflow velocity recordings by Doppler have limited value for the recognition of coronary artery disease, since the E/A ratio is profoundly influenced by other factors, such as heart rate and age.

Relation between serum digoxin concentration and the electrocardiogram.

The relation between serum digoxin concentration and the electrocardiogram was assessed by correlating computerized measurements of electrocardiographic parameters (PR, QRS, QT and QTc intervals, ST segment, and T-wave amplitude) with the serum digoxin concentration in 97 patients on digoxin maintenance therapy and in 40 nondigitalized control subjects. None of the patients had unstable ischemic heart disease, electrolyte disorders, medication known to influence the ST segment, and/or the presence of a bundle-branch block or ventricular hypertrophy. We found a trend toward lengthened PR interval and shortened QT and QTc intervals in digitalized versus nondigitalized patients. Increasing serum digoxin concentrations were associated with progressive depression of the ST segment and decreased T-wave amplitude (p less than 0.001). A normal ST segment in four leads (I, aVF, V5, V6) excluded the presence of a serum digoxin concentration greater than 1.3 ng/ml in our patients, whereas severe ST-segment depression with a J point of greater than or equal to 100 microV was a strong indicator for the presence of a serum digoxin concentration greater than 2.0 ng/ml in our selected patient population (specificity 99%, sensitivity 30%, predictive accuracy 85%). We conclude that computerized electrocardiographic analysis of the ST segment may provide clinically useful information for the management of selected patients on digitalis therapy and may therefore increase the diagnostic yield of the electrocardiogram in predicting the presence of higher serum digoxin concentrations in a small but significant percentage of patients.