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PubMedDate not supplied

Ischemic event characteristics determine the extent of myocardial stunning in conscious dogs.

Both the severity and duration of postischemic myocardial dysfunction ("stunned" myocardium) are unpredictable and may vary considerably between subjects that underwent apparently similar ischemic insults. To explain this heterogeneous response of the heart to ischemia and reperfusion, we investigated the determinants of stunning in conscious dogs. Twenty-five dogs were chronically instrumented for measurement of global and regional myocardial performance (wall thickening) and myocardial perfusion (coloured microspheres). A hydraulic occluder was positioned around the LAD coronary artery. Conscious dogs were subjected to acute coronary artery occlusions of predetermined duration (2, 5 and 10 min), followed by complete reperfusion. Multiple regression analysis identified the following variables as determinants of postischemic contractile recovery: 1) the duration of ischemia (p < 0.01),2) the amount of collateral perfusion (p = 0.01) and 3) left ventricular end-diastolic pressure during ischemia (p < 0.01). Neither the severity of regional dyskinesia during ischemia nor indices of global systolic hemodynamic performance correlated with the rate of recovery. Our data confirm that myocardial stunning relates primarily to the intensity of preceding ischemia. Variations in the preexisting level of collateral perfusion may result in markedly different recovery profiles. Except for LV end-diastolic pressure during ischemia, indices of global and regional cardiac performance fail to predict the severity of postischemic contractile failure.

Animals↗

PubMed2004

Potential application of tissue Doppler imaging to assess regional left ventricular diastolic function in patients with hypertrophic cardiomyopathy: comparison with 123I-beta-methyl iodophenyl pentadecanoic acid myocardial scintigraphy.

BACKGROUND: Tissue Doppler imaging (TDI) has been utilized to evaluate left ventricular myocardial dysfunction in patients with hypertrophic cardiomyopathy (HCM); however, no clear explanation for the abnormality of TDI variables has been forthcoming. HYPOTHESIS: Peak negative myocardial velocity gradient (MVG) derived from TDI may correlate with a disorder of fatty acid metabolism in patients with HCM. METHODS: Tissue Doppler imaging and 123I-beta-methyl iodophenyl pentadecanoic acid (123I-BMIPP) myocardial scintigraphy were performed in 15 patients with asymmetric septal hypertrophy (mean age 47 +/- 18 years) and in 12 healthy controls (mean age 43 +/- 10 years). RESULTS: In early 123I-BMIPP images, accumulation defects were observed in the ventricular septum in 12 patients and in the posterior wall in 8 patients with HCM. Peak negative MVG in the ventricular septum (1.1 +/- 0.5 vs. 2.8 +/- 0.5, p < 0.0001) and posterior wall (5.2 +/- 1.4 vs. 6.7 +/- 0.8, p < 0.01 ) was significantly lower in the HCM group than in the controls; also, these parameters were significantly lower in patients with than in those without a defect in the region in question. The peak negative MVG in the ventricular septum and posterior wall correlated inversely with the washout rate in all subjects. CONCLUSIONS: Peak negative MVG according to TDI is related to disorder of fatty acid metabolism in the regional left ventricular myocardium of patients with HCM.

Cardiomyopathy, Hypertrophic↗

PubMed1982

[Computer analysis of wo-dimensional echocardiogram for the quantitative evaluation of left ventricular asynergy in myocardial infarction].

Quantitative assessment of left ventricular asynergy in myocardial infarction was made by computer analysis of the two-dimensional echocardiogram. Short-axis cross-sectional images of the left ventricle at the levels of the mitral valve, papillary muscle and apex were recorded by a phased array sector scanner in 20 patients with myocardial infarction and ten normal controls. End cardial and epicardial outlines at end-diastole and end-systole were traced and analyzed by a computer system. Short-axis cross-sectional images of the left ventricle were divided equally into octants and analyzed with a fixed external reference system, using the center of gravity of end-diastolic left ventricular cavity and the axis intersecting this and the right side of the posterior interventricular septum as the reference point and line. Segmental hemiaxis, area, wall thickness and those changes during cardiac cycle were measured and calculated in each octants. Regional contractility of the left ventricle was evaluated by systolic percent change of segmental hemiaxis, area and wall thickness. These parameters were significantly reduced in the infarcted segments documented by left ventriculography and electrocardiography. The area method is better than the hemiaxis system in both reproducibility and variability. The center of gravity of the left ventricular cavity determined by the computer shifted slightly towards the anterior wall during systole in normal subjects, possibly reflecting anterior swinging motion of the entire heart. The center of the gravity of the left ventricular cavity in myocardial infarction showed the tendency to shift towards the infarcted region, suggesting the possibility that the location of asynergic area can be detected by determining the direction of the gravity center shift during systole in patients with a single infarction. This finding gives a basis of using the fixed reference system for the detection of asynergy. The use of computers for the analysis of short-axis two-dimensional echocardiographic images is very useful for the quantification of regional contractility of the left ventricle in a clinical setting.

Computers↗

PubMed1996

CONRAD: a method for identification of variable and conserved regions within proteins by scale-space filtering.

Advanced sequencing techniques allow rapid deduction of individual amino acid sequences of highly related proteins. Due to their quasi-species nature, viral genomes (e.g. HIV-1) represent one of the most common sources of related proteins. Another example of related proteins are immunoglobulins. Local differences in amino acid conservation are useful indicators of potential domain structures and immunological or functional epitopes prior to structural analysis of proteins. Although variability indices can be calculated by several methods, delineation of boundaries between sequence stretches with similar variability indices is left to the user. We use algorithmic scale-space filtering for delineation of conserved and variable sequence stretches within a protein which is performed on an algorithmic basis avoiding arbitrary assignments. Out method correctly identified variable regions for the human immunoglobulin lambda-chain V-regions (subgroup I). Prediction of the variable regions of the HIV-1 gp120 env protein was in agreement with empirical derived definitions. These examples indicate that our method is useful for the regional assignment of protein variability solely on the basis of amino acid sequences.

Algorithms↗

PubMed1984

Hydrogen peroxide contrast echocardiography: quantification in vivo of myocardial risk area during coronary occlusion and of the necrotic area remaining after myocardial reperfusion.

During sustained coronary occlusion in canine preparations, the extent of regions that fail to show contrast enhancement when imaged by supra-aortic hydrogen peroxide contrast echocardiography (SHPCE) has been shown to correlate well for single cross sections with the extent of malperfused myocardium "at risk" of infarction. In the present study, SHPCE was investigated as a means of determining the fraction of total left ventricular mass at risk during occlusion. Since necrotic tissue has low blood flow even when reperfused, we also investigated the potential of quantitating the extent of infarcted myocardium by measuring the extent of contrast defects seen with SHPCE performed during reperfusion. In 20 dogs the fraction of the left ventricle showing a contrast defect during coronary occlusion correlated well with the fraction of the left ventricular mass "at risk" by an autoradiographic technique (autoradiography = 0.83 echocardiography + 8.6%; r = .89, SEE = 4.5%). SHPCE was also performed after 3 hr of reperfusion following occlusions varying in duration from 60 to 150 min. The fraction of the ventricle showing a contrast defect during reperfusion predicted the infarcted portion of the left ventricle as shown by triphenyl tetrazolium chloride staining (% left ventricle infarcted = 0.81 echocardiography + 3.3%; r = .84, SEE = 5.3%). Observer variability for the fraction of the ventricle showing a contrast defect was excellent during both occlusion and reperfusion. The ratio of the left ventricular extent of contrast-negative regions during reperfusion and occlusion was used to calculate a necrosis-to-risk index in vivo that correlated relatively well with the myocardial necrosis-to-risk ratio determined morphologically (r = .77, SEE = 16%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2025

A whole-brain voxel-based analysis of structural abnormalities in PTSD: An ENIGMA-PGC study.

BACKGROUND: Patients with posttraumatic stress disorder (PTSD) exhibit smaller regional brain volumes in commonly reported regions including the amygdala and hippocampus, regions associated with fear and memory processing. In the current study, we have conducted a voxel-based morphometry (VBM) meta-analysis using whole-brain statistical maps with neuroimaging data from the ENIGMA-PGC PTSD working group. METHODS: T1-weighted structural neuroimaging scans from 36 cohorts (PTSD n = 1309; controls n = 2198) were processed using a standardized VBM pipeline (ENIGMA-VBM tool). We meta-analyzed the resulting statistical maps for voxel-wise differences in gray matter (GM) and white matter (WM) volumes between PTSD patients and controls, performed subgroup analyses considering the trauma exposure of the controls, and examined associations between regional brain volumes and clinical variables including PTSD (CAPS-4/5, PCL-5) and depression severity (BDI-II, PHQ-9). RESULTS: PTSD patients exhibited smaller GM volumes across the frontal and temporal lobes, and cerebellum, with the most significant effect in the left cerebellum (Hedges' g = 0.22, pcorrected = .001), and smaller cerebellar WM volume (peak Hedges' g = 0.14, pcorrected = .008). We observed similar regional differences when comparing patients to trauma-exposed controls, suggesting these structural abnormalities may be specific to PTSD. Regression analyses revealed PTSD severity was negatively associated with GM volumes within the cerebellum (p corrected  = .003), while depression severity was negatively associated with GM volumes within the cerebellum and superior frontal gyrus in patients (p corrected  = .001). CONCLUSIONS: PTSD patients exhibited widespread, regional differences in brain volumes where greater regional deficits appeared to reflect more severe symptoms. Our findings add to the growing literature implicating the cerebellum in PTSD psychopathology.

Humans↗

PubMed2005

Giant proliferating trichilemmal tumor of the gluteal region.

BACKGROUND: Proliferating trichilemmal tumors are rare cutaneous neoplasms that show features of typical pilar cysts but also show extensive epithelial proliferation, variable cytologic atypia, and mitotic activity. Proliferating trichilemmal tumors are benign lesions; however, there are numerous reports of malignant proliferating trichilemmal tumors. OBJECTIVE: We present a case of benign proliferating trichilemmal tumor of an 81-year-old woman that was located on the left superior gluteal region for 30 years. METHODS: A tumor measuring 9 x 7 cm was surgically excised with a 1 cm conservative margin of normal tissue. RESULTS: Based on the histopathologic findings of tumor, this case was diagnosed as proliferating trichilemmal tumor. The patient's condition was successfully treated with total excision. CONCLUSIONS: Our case is an unusual presentation of proliferating trichilemmal tumor. Physicians should be aware of this entity while differentiating cutaneous tumor located on the gluteal region.

Aged, 80 and over↗

PubMed1981

Changes in regional myocardial blood flow and variable development of hypertrophy after aortic banding in puppies.

Supravalvar aortic banding was performed in 6 to 12 week puppies. Sixteen animals were studied 7.3 (3.5 to 10) months later, closed-chested under morphine-chloralose, catheters being positioned in the great vessels and heart, including the left atrium for microsphere injection. Compared with 11 controls, eight dogs developed biventricular hypertrophy, four isolated left ventricular hypertrophy and four had no hypertrophy. The left ventricular systolic pressure was similar (P greater than 0.05) in these 3 banded groups (mean, 30 +/- 2 [SEM] kPa, [222 +/- 16 mmHg], n = 16). The left ventricle was divided into three coronal slices with approximately 59 samples being taken from subendocardial, midwall, and subepicardial layers and additional samples from the atria and right ventricle for regional myocardial flow measurement. As left ventricular hypertrophy increased, the subendocardial/subepicardial flow ratio decreased (r = -0.8). Heterogeneity of left ventricular regional myocardial flow, including a base-to-apex decrease in flow, present in controls, was markedly reduced in the banded dogs. Analysis of variance was found to be the most sensitive test for detecting left ventricular perfusion abnormalities since in banded dogs without hypertrophy, total and regional subendocardial/subepicardial flow ratios were not significantly different from control values, whereas the subendocardial circumferential flow pattern determined by analysis of variance was significantly different from control in these dogs (P less than 0.05).

Animals↗

PubMed1992

Segmental systolic responses to brief ischemia and reperfusion in the hypertrophied canine left ventricle.

OBJECTIVES AND BACKGROUND: Left ventricular hypertrophy is associated with increased mortality, increased myocardial infarct size and an increased incidence of sudden death. Although reperfusion after ischemia has been shown to result in decreased infarct size and recovery of systolic thickening, it is unknown how left ventricular hypertrophy might influence recovery of regional systolic thickening after ischemia and reperfusion. We hypothesized that left ventricular hypertrophy might attenuate or abolish the functional response to reperfusion. METHODS: Three groups of chronically instrumented, conscious dogs (dogs with left ventricular hypertrophy and hypertension; dogs with left ventricular hypertrophy and reduced blood pressure and a control group without hypertrophy and with normal blood pressure) underwent 15 min of ischemia and 24 h of reperfusion. Segmental systolic thickening was measured by sonomicrometers and myocardial segments were grouped by percent of control segmental systolic thickening retained at 15 min of ischemia (class 1 greater than or equal to 67%, class 2 from 0% to 66%, class 3 less than 0% control systolic thickening). The recovery of each class of segment was measured serially during reperfusion. Hemodynamic variables and regional myocardial blood flow were also measured. RESULTS: There were no differences among groups in recovery of segmental systolic thickening for class 1 segments. Systolic thickening in class 2 (hypokinetic) segments was significantly depressed (p less than 0.05 compared with control value) in the group with left ventricular hypertrophy and reduced blood pressure (but not in the group with hypertrophy and hypertension) during early reperfusion; systolic thickening in class 3 (dyskinetic) segments showed a similar trend in the group with hypertrophy and reduced pressure. CONCLUSIONS: Although left ventricular hypertrophy with hypertension did not attenuate the contractile response to reperfusion, hypertrophy with reduced blood pressure was associated with significantly greater depression of segmental systolic thickening early during reperfusion.

Animals↗

PubMed2002

Genetic contributions to regional variability in human brain structure: methods and preliminary results.

Twin studies provide one approach for investigating and partitioning genetic and environmental contributions to phenotypic variability in human brain structure. Previous twin studies have found that cerebral volume, hemispheric volume, ventricular volume, and cortical gyral pattern variability were heritable. We investigated the contributions of genetic and environmental factors to both global (brain volume and lateral ventricular volume) and regional (parcellated gray matter) variability in brain structure. We examined MR images from 10 pairs of healthy monozygotic and 10 pairs of same-sex dizygotic twins. Regional gray matter volume was estimated by automated image segmentation, transformation to standard space, and parcellation using a digital atlas. Heritability was estimated by path analysis. Estimated heritability for brain volume variability was high (0.66; 95% confidence interval 0.17, 1.0) but the major effects on lateral ventricular volume variability were common and unique environmental factors. We constructed a map of regional brain heritability and found large genetic effects shared in common between several bilateral brain regions, particularly paralimbic structures and temporal-parietal neocortex. We tested three specific hypotheses with regard to the genetic control of brain variability: (i) that the strength of the genetic effect is related to gyral ontogenesis, (ii) that there is greater genetic control of left than of right hemisphere variability, and (iii) that random or fluctuating asymmetry in bilateral structures is not heritable. We found no evidence in support of the first two hypotheses, but our results were consistent with the third hypothesis. Finally, we used principal component (PC) analysis of the genetic correlation matrix, to identify systems of anatomically distributed gray matter regions which shared major genetic effects in common. Frontal and parietal neocortical areas loaded positively on the first PC; some paralimbic and limbic areas loaded negatively. Bilateral insula, some frontal regions, and temporal neocortical regions functionally specialized for audition and language loaded strongly on the second PC. We conclude that large samples are required for powerful investigation of genetic effects in imaging data from twins. However, these preliminary re. sults suggest that genetic effects on structure of the human brain are regionally variable and predominantly symmetric in paralimbic structures and lateral temporal cortex.

Algorithms↗

PubMed1997

Regional cerebral blood flow in late-onset schizophrenia: a SPECT study using 99mTc-HMPAO.

Functional neuroimaging studies have been performed in many young patients with schizophrenia, but late-onset schizophrenia (LOS) remains largely unexamined by these techniques. We predicted that LOS would demonstrate regional cerebral blood flow (rCBF) abnormalities similar to those seen in early-onset schizophrenia (EOS), but with a basis in demonstrable coarse brain disease. The subjects were 15 LOS and 7 EOS patients and 27 healthy controls. Each was given a detailed clinical and neuropsychological assessment and underwent MRI and Tc99m-HMPAO single photon emission computed tomography (SPECT) scans. The LOS subjects had a significantly lower cerebral hemispheric perfusion than controls, with a lower perfusion in the frontal and temporal lobes bilaterally. The LOS group also had significantly lower left-to-right hemisphere blood flow ratios. EOS subjects had a lower frontal perfusion than the controls, which was significant in the left frontal region. The temporal perfusion in the EOS subjects was greater than in the LOS group, and not different from the control subjects. Left temporal perfusion was the most discriminating variable between LOS and control subjects on logistic regression. Correlations of perfusion with MRI were generally low with the exception that the asymmetry indices were significantly correlated, and basal ganglia perfusion correlated with basal ganglia hyperintensities on MRI. The total cerebral perfusion index correlated significantly with the mini-mental state examination (MMSE) score, and the temporal lobe perfusion correlated with MMSE scores and some verbal memory measures. In the schizophrenic groups, perfusion correlated nonsignificantly with symptom profiles. We conclude that our findings of temporal and frontal rCBF abnormalities, especially on the left side, in LOS are similar to those reported in schizophrenia in general. The results do not provide evidence for coarse brain disease underlying the rCBF abnormalities in LOS, or support the specificity of these abnormalities for particular subsyndromes of schizophrenia.

Age of Onset↗

PubMed2006

[Organization and transcription strategy of genome of Bombyx mori bidensovirus (China isolate) VD1].

To better understand the genomic structure and function of Bombyx mori bidensovirus (China isolate) VD1, the VD1 was purified and cloned into the pUC119 vector, and the complete nucleotide sequence of VD1 was determined. Sequence analysis showed that VD1 genome consisted of 6543 nts including inverted terminal repeats (ITRs) of 224 nts. In the viral genome, three major open reading frames (ORF1, ORF2 and ORF3) in the plus strand and one major ORF (ORF4) in the complementary strand were identified. Comparison of the complete genome sequence between Bombyx mori bidensovirus (China isolate) and BmDNV-2 (Yamanashi isolate) showed an identity of 98.4% in VD1, with a total number of 104 bp substitutions and 1 bp insertions found in Bombyx mori bidensovirus (China isolate), the highly variable regions were mainly located in VD1 ORF3 and VD1 ORF4. Northern blotting revealed that VD1 contained 1.1 kb and 1.5 kb transcript in the left-half 'plus' strand, and one transcript about 3.3 kb of 'minus' strand in the right-half. Sequencing of 3' and 5' ends of transcript products showed the 1.1 kb transcript started at nt 290 and ended at nt 1437, the 1.5 kb transcript was found to start nt 1423 and ended at 2931, and the 3.3 kb transcript was found to start nt 6287 and ended at nt 2922. Therefore, the 1.5 kb transcript in the left-half plus' strand and 3.3 kb transcripts of minus' strand in the right-half overlapped for 10 nts at the 3' ends. These results indicate that this virus employs a transcription strategy that is radically different from that of the other reported DNVs.

Amino Acid Sequence↗

PubMed1981

Myosin types and fiber types in cardiac muscle. I. Ventricular myocardium.

Antisera against bovine atrial myosin were raised in rabbits, purified by affinity chromatography, and absorbed with insolubilized ventricular myosin. Specific anti-bovine atrial myosin (anti-bAm) antibodies reacted selectively with atrial myosin heavy chains, as determined by enzyme immunoassay combined with SDS-gel electrophoresis. In direct and indirect immunofluorescence assay, anti-bAm was found to stain all atrial muscle fibers and a minor proportion of ventricular muscle fibers in the right ventricle of the bovine heart. In contrast, almost all muscle fibers in the left ventricle were unreactive. Purkinje fibers showed variable reactivity. In the rabbit heart, all atrial muscle fibers were stained by anti-bAm, whereas ventricular fibers showed a variable response in both the right and left ventricle, with a tendency for reactive fibers to be more numerous in the right ventricle and in subepicardial regions. Diversification of fiber types with respect to anti-bAm reactivity was found to occur during late stages of postnatal development in the rabbit heart and to be influenced by thyroid hormone. All ventricular muscle fibers became strongly reactive after thyroxine treatment, whereas they became unreactive or poorly reactive after propylthiouracil treatment. These findings are consistent with the existence of different ventricular isomyosins whose relative proportions can vary according to the thyroid state. Variations in ventricular isomyosin composition can account for the changes in myosin Ca2+-activated ATPase activity previously observed in cardiac muscle from hyper- and hypothyroid animals and may be responsible for the changes in the velocity of contraction of ventricular myocardium that occur under these conditions. The differential distribution of ventricular isomyosins in the normal heart suggests that fiber types with different contractile properties may coexist in the ventricular myocardium.

Animals↗

PubMed1996

Hearing and saying. The functional neuro-anatomy of auditory word processing.

The neural systems involved in hearing and repeating single words were investigated in a series of experiments using PET. Neuropsychological and psycholinguistic studies implicate the involvement of posterior and anterior left perisylvian regions (Wernicke's and Broca's areas). Although previous functional neuroimaging studies have consistently shown activation of Wernicke's area, there has been only variable implication of Broca's area. This study demonstrates that Broca's area is involved in both auditory word perception and repetition but activation is dependent on task (greater during repetition than hearing) and stimulus presentation (greater when hearing words at a slow rate). The peak of frontal activation in response to hearing words is anterior to that associated with repeating words; the former is probably located in Brodmann's area 45, the latter in Brodmann's area 44 and the adjacent precentral sulcus. As Broca's area activation is more subtle and complex than that in Wernicke's area during these tasks, the likelihood of observing it is influenced by both the study design and the image analysis technique employed. As a secondary outcome from the study, the response of bilateral auditory association cortex to 'own voice' during repetition was shown to be the same as when listening to "other voice' from a prerecorded tape.

Auditory Perception↗

PubMed1993

Increased activity of the sarcoplasmic reticular calcium pump in porcine stunned myocardium.

OBJECTIVE: The aim was to determine whether changes in sarcoplasmic reticular Ca2+ transport activity and the degree of phosphorylation of phospholamban of "stunned" myocardium are involved in the reversible depression of contractile function. METHODS: In anaesthetised open chest swine, stunning was induced by subjecting the myocardium perfused by the left anterior descending coronary artery to two cycles of 10 min of occlusion and 30 min of reperfusion. Before and after stunning, systemic haemodynamic variables and regional myocardial function and perfusion were determined, while biopsies were taken for determination of the content of high energy phosphate compounds. Sarcoplasmic reticular function (ATP dependent Ca2+ transport and phosphorylation of phospholamban) of the stunned and control myocardium was determined at the end of the stunning protocol. RESULTS: In the stunned myocardium the segment length shortening decreased from 17.4(SD 4.0)% to 3.5(4.4)%, while perfusion was 38% less than at baseline. ATP and total adenine nucleotide levels of the stunned myocardium were about 35% lower than in the control myocardium, but the energy charge was normal as creatine phosphate levels had increased by 66% over the content determined at baseline. Ca2+ uptake by the sarcoplasmic reticulum isolated from the stunned region was 17% (p < 0.05) higher than Ca2+ uptake from the control region [1240(303) and 1450(280) nmol.min-1.mg-1 protein, respectively]. In the presence of exogenous cyclic AMP dependent protein kinase the amount of 32P incorporated into phospholamban was similar for both myocardial regions. CONCLUSIONS: In this model of stunned porcine myocardium, the phosphorylation state of phospholamban was unchanged, but Ca2+ uptake by the sarcoplasmic reticulum was slightly increased. The results indicate that a change in active Ca2+ transport by the sarcoplasmic reticulum is most likely not to be the principal cause of contractile dysfunction of stunned myocardium.

Adenosine Diphosphate↗

PubMed1976

Limitations of thallium-201 myocardial perfusion scintigrams.

The reliability of myocardial perfusion scintigrams with thallium-201 (201Tl) for detecting areas of hypoperfusion was assessed in 16 closed-chest dogs. Variable areas of ischemia were produced either by occluding or stenosing the left anterior descending coronary artery. Cardiac scintigrams taken in four projections were compared with regional myocardial perfusion maps. Segmental concentrations and segmental perfusions were quantitated by counting the emissions from 201Tl and the microspheres in each of 96 segments of the left ventricle. In addition, studies with a phantom were performed. The results indicate: 1) The emissions from 201Tl and from microspheres correlated well in ischemic segments (r = 0.93 +/- SE 0.02). 2) Seven of twelve ischemic hearts had definitely abnormal scintigrams and in each of these the hypoperfused zone was greater than 4.9 grams and perfusion was decreased by more than 45%. 3) In the phantom, abnormal scintigrams could be detected in the presence of lesser deficits than in the dogs. The limitation of the thallium perfusion scintigrams will be the inconsistent detection of small perfusion deficits.

Animals↗

PubMed1980

[Pseudomonas aeruginosa bacteriophages with DNA structure similar to the DNA structure of Mu1 phage. II. Evidence for similarity between D3112, B3, and B39 bacteriophages: analysis of DNA splits by restriction endonucleases, isolation of D3112 and B3 recombinant phages].

It is found that bacteriophages B3 and B39 specific for Pseudomonas aeruginosa have the same genome structure as previously described phage D3112. On the right (S) end of their genomes a variable non-phage DNA is located (approximately 0.9-2.5 kilobases for different phages). It is probable that this variable DNa has its origin from different regions of bacterial chromosome. In genome of one of the phages, B3 phage, such variable DNA (not more than 150 base pairs) was found on the left end of DNA molecule. Isolation of a viable B3XD3112 recombinant phage and analysis of its genome with restriction technique and with studies of homo- and heteroduplex molecules had confirmed genetical relationship of B3 and D3112. Some essential non-homology of B3 and D3112 DNAs have been found on the right ends of genomes of the phages.

Bacteriophages↗

PubMed1981

"Abnormal" responses of ejection fraction to exercise, in healthy subjects, caused by region-of-interest selection.

We performed serial exercise equilibrium radionuclide angiography in eight normal subjects with each subject executing three tests: control, after nitroglycerin, and after propranolol. The left-ventricular ejection fraction (EF) was calculated by two methods: (a) fixed region-of-interest (FROI) using a single end-diastolic ROI, and (b) variable region-of-interest (VROI) where an end-diastolic and end-systolic region of interest were used. Abnormal maximal EF responses occurred in five of eight subjects during control using FROI but in zero of eight employing VROI (p < 0.05). After nitroglycerin, three of eight subjects had abnormal responses by FROI, but zero of eight were abnormal by VROI (p < 0.05). After propranolol, blunted EF responses occurred in three of seven by both methods. Falsely abnormal EF responses to execrise RNA may occur due to the method of region-of-interest selection in normal subjects with normal or high ejection fractions.

Adult↗