Influence of testosterone substitution on sperm suppression by LHRH agonists

To investigate the effect of LHRH (GnRH) agonists on sperm suppression, we studied the effect of a depot preparation of D-Trp6 LHRH in 10 normal men for 30 weeks. In addition, to determine the role of androgenic substitution on sperm suppression, the volunteers were divided into two groups: group 1 (n = 5) received a low dose T substitution (125 mg of T enanthate every month), while group 2 (n = 5) received a normal T substitution (120 mg of T undecanoate every day). Four men became azoospermic in group 1 and none in group 2. Moreover, administration of additional T injections in 1 volunteer of group 1 resulted in the reappearance of spermatozoa in the ejaculate. Return to the low dose therapy produced azoospermia. These results suggest that testosterone supplementation supports spermatogenesis.

Collaborative study on antigens for immunodiagnosis of Schistosoma japonicum infection

Six research laboratories in Australia, Japan, the Philippines and the USA participated in a collaborative evaluation of immunodiagnostic tests for Schistosoma japonicum infections. The serum bank consisted of 385 well-documented sera from Brazil, Kenya, Philippines, Republic of Korea and Europe. Twelve S. japonicum antigen/test system combinations were evaluated.Crude S. japonicum egg antigens showed the highest sensitivity and specificity. The defined or characterized antigens showed no advantage over the crude antigens. Quantitative seroreactivity of all S. japonicum antigens showed a positive correlation with faecal egg counts (log x + 1) in all age groups. The performance of the circumoval precipitin test was satisfactory within the same laboratory but with differences in the results between laboratories. A monoclonal antibody used in a competitive radioimmunoassay test system performed as well as the crude egg antigens.The high sensitivity of crude S. japonicum antigens now permits further evaluation for wide-scale use in public health laboratories of endemic areas to support control efforts.

Quantitation of extent, depth, and severity of planar thallium defects in patients undergoing exercise thallium-201 scintigraphy

Previous quantitation of exercise-redistribution planar 201TI scintigraphy has shown high sensitivity and specificity in the detection of coronary artery disease and improved detection of individual coronary stenoses over visual analysis. By using similar methodology based on the circumferential profile method, we studied 133 patients to quantitatively assess the extent, depth, and severity of thallium defects compared with consensus visual analysis. These quantitative measurements are objective, requiring only three operator interactions. In comparing quantitative and visual results, a close correlation was found for measurement of extent of thallium defect (r = 0.73) and severity of defect (r = 0.79). In detecting patients with the high-risk scintigraphic pattern of a severe stress thallium defect, a quantitative depth score of greater than or equal to 36 had an 81% sensitivity and an 82% specificity. Thus, this nearly automatic, computerized quantitative method allows objective determination of extent, severity, and depth of planar 201TI defects.

Searching for autolysin functions. Characterization of a pneumococcal mutant deleted in the lytA gene

The first mutant of Streptococcus pneumoniae showing a complete deletion in the lytA gene coding for the N-acetylmuramyl-L-alanine amidase has been isolated and characterized. This amidase was previously the only autolysin detected in this species. This mutant shows a normal growth rate and can be transformed using either chromosomal or plasmid DNA. The most remarkable biological consequences of the absence of the amidase are the formation of small chains (six to eight cells) and the absence of lysis in the stationary phase of growth. In addition, this mutant exhibits a tolerant response against the beta-lactam antibiotics.

The echocardiographic spectrum of atrial myxoma: a ten-year experience

We analyzed the echocardiograms of 28 patients with a left atrial myxoma and two with a right atrial myxoma. Our purpose was to evaluate the value of echocardiography for the diagnosis of these cardiac masses. Only 59% of the m-mode echocardiograms in patients with a left atrial myxoma showed the characteristic findings of multiple diastolic echoes within the mitral orifice as well as abnormal systolic echoes within the left atrium. M-mode echocardiograms were atypical for left atrial myxoma in the remaining patients, and a definitive diagnosis could not be established on the basis of this procedure in six of the patients (22%). Two-dimensional echocardiography showed the presence of a left atrial mass in all 16 patients who had the procedure, and aided in understanding the atypical m-mode recordings. There was a close relationship (r =.82) between two-dimensional echocardiographic measurements of the myxomas' size and pathologic measurements. Both right atrial myxomas could be identified on the m-mode echocardiogram. Our experience indicates that two-dimensional echocardiography is superior to the m-mode technique for the diagnosis and characterization of left atrial myxomas.

[Biomorphogenetic changes caused by the application of precocene II in nymphs of Triatoma infestans (Klug, 1834) (Hemiptera, Reduviidae, Triatominae)]

The morphogenetic effect of precocene II on 4th instar nymphs of Triatoma infestans was examined. Topical treatment with precocene II (200, 300 and 400 micrograms/nymph) induced the formation of adultoids with the following characteristics: rudimentary wings, three segmented tarsi, ocelli, deformed genitalia and mouth-parts and testes with intermediary development. Precocene II also increases the duration of the molting cycle. The survival of the adultoid insects was related to the inverse of the applied doses. These data extend our knowledge of the action of precocene II on triatominae species.

Differential expression of HLA class I and II antigens in primary and metastatic melanomas

Class I and II histocompatibility antigen expression was studied in cryostat sections of biopsy tissues from 15 patients diagnosed as suffering from malignant melanoma, using monoclonal antibodies against HLA class I and II monomorphic determinants and an indirect immunofluorescence technique. Class I antigens were detected in three of the four primary melanomas and in five of the eleven metastatic melanomas. Class II antigens were expressed only in metastatic melanomas, in three out of eleven cases. Some tumour cell suspensions were obtained and short-term cultures were established. Radiobinding and immunoprecipitation studies were carried out in two cases, named M6 and M8. The results were comparable to those obtained with direct immunofluorescence. We modulated the expression of class I and II HLA antigens with interferon in M6 when adapted to tissue culture. This melanoma was class I and II negative; after IFN gamma treatment it became strongly positive for class I and II antigens. In addition we have demonstrated, using Southern blot analysis with the restriction enzymes PvuII and EcoRI, that the M6 melanoma does not have any detectable alterations in its class II beta genes.

Noninvasive quantification of the extent of jeopardized myocardium in patients with single-vessel coronary disease by stress thallium-201 single-photon emission computerized rotational tomography

In 22 patients with single-vessel coronary artery disease and no history of infarction, stress Tl-201 rotational tomography was used to quantify the extent of jeopardized myocardium. The vertical long- and short-axis tomograms were quantified by means of maximum-count circumferential profile analysis. The scintigraphic extent of jeopardized myocardium was expressed as the percentage of profile points falling 2.5 standard deviations below a previously established mean normal profile and was correlated to a quantitatively expressed angiographic extent of jeopardized myocardium. The extent of jeopardized myocardium varied from 1% to 55% by tomography and 8% to 50% by angiography and correlated with an r = 0.79 and a 10% standard error of the estimate. Defect intensity, reflecting the mean depth by which the abnormal points fell below the normal value of greater than or equal to 10%, was 100% specific for a coronary stenosis of greater than or equal to 70%. In conclusion, this study demonstrates that: patients with single-vessel disease have highly variable extents of hypoperfused myocardium defined by Tl-201 tomography and coronary arteriography, there is a fair relationship between angiographic jeopardy score and perfusion defects by Tl-201 tomography during exercise, and Tl-201 tomography may be used to noninvasively determine the extent of hypoperfused myocardium in coronary artery disease.

Digital signal and image processing in echocardiography. The American Society of Echocardiography

Digital signal and image processing techniques are acquiring an increasingly important role in the generation and analysis of cardiac images. This is particularly true of 2D echocardiography, in which image acquisition, manipulation, and storage within the echocardiograph, as well as quantitative analysis of echocardiographic data by means of "off-line" systems, depend upon digital techniques. The increasing role of computers in echocardiography makes it essential that echocardiographers and technologists understand the basic principles of digital techniques applied to echocardiographic instrumentation and data analysis. In this article, we have discussed digital techniques as applied to image generation (digital scan conversion, preprocessing, and postprocessing) as well as to the analysis of image data (computer-assisted border detection, 3D reconstruction, tissue characterization, and contrast echocardiography); a general introduction to off-line analysis systems was also given. Experience with other cardiac imaging methods indicates that digital techniques will likely play a dominant role in the future of echocardiographic imaging.

Outpatient keratoplasty

Outpatient keratoplasty in 103 patients (46 males and 57 females ranging in age from 1 to 90 years) produced no instances of infection, shallow or flat anterior chambers, or anterior synechia formation. Postoperative discomfort was minimal.

HLA antigens in hemophiliacs A with or without factor VIII antibodies in a Venezuelan Mestizo population

Twenty-eight unrelated hemophilia A patients, seven of them with anti-factor VIII antibodies were typed for HLA-A, B, C antigens and 25 of them for HLA-DR. The results show a significant difference in HLA-DR4 frequency between hemophiliacs with antibodies who lack this antigen and hemophiliacs without antibodies, in whom HLA-DR4 is increased as compared to a healthy control series. This data suggests that DR4 may be associated with a factor preventing anti-factor VIII immunization.

Thallium-201 stress-redistribution myocardial rotational tomography: development of criteria for visual interpretation

Despite high sensitivity and specificity for overall detection of coronary artery disease (CAD), planar stress-redistribution thallium-201 (Tl-201) scintigraphy remains suboptimal in localizing disease, because of overlap of myocardial segments. Single photon emission computerized tomography (SPECT), by providing three-dimensional representation of myocardial Tl-201, offers promise for improved localization of CAD. In 50 consecutive patients (22 normal and 28 with CAD), who underwent SPECT stress-redistribution Tl-201 imaging, we systemically developed visual interpretive criteria for perfusion abnormality on SPECT. For overall detection of disease, the best criterion for abnormality was greater than or equal to 8 sectors of moderately decreased Tl-201 uptake. With this criterion, the true positive and true negative rates for overall detection of disease were 96% and 91%, respectively. The best criterion for significant defect in the anterior or posterior coronary circulation was greater than or equal to 3 sectors of moderately decreased Tl-201 uptake. With this criterion, the true positive and true negative rates for anterior circulation disease were 71% and 100%, respectively. With respect to posterior circulation disease, the true positive and true negative rates were 100% and 50%, respectively. Regarding identification of dual circulation disease, the true positive and true negative rates were 71% and 82%, respectively.

Slow regional clearance of myocardial thallium-201 in the absence of perfusion defect: contribution to detection of individual coronary artery stenoses and mechanism for occurrence

As a result of the "spatially relative" nature of perfusion defect analysis of stress-redistribution thallium-201 (201Tl) scintigrams, hypoperfused myocardial segments may not appear as perfusion defects but they may demonstrate a slow washout rate of 201Tl that can be analyzed in a "spatially nonrelative" manner. Quantitative analysis of perfusion defects and slow washout rate of 201Tl was performed on scintigrams from 116 consecutive patients with adequate exercise tests, defined as achievement of 85% or more of age-predicted maximum heart rate or development of angina or ST segment depression. A total of 232 diseased and 116 nondiseased vessels were found in the patients. Additional analysis of slow washout rate significantly (p less than .05) improved sensitivity for detection of disease in the left anterior descending (from 74% to 82%), left circumflex (from 40% to 61%), and right coronary arteries (from 78% to 90%) without significant loss of specificity. This improvement resulted from the additional detection of 32 of 232 (14%) diseased vascular distributions when the isolated slow washout rate of 201Tl was also determined. In nine of these 32, isolated slow washout rate was associated with another region with isolated slow washout rate in the contralateral myocardial segment. Coronary arteriography revealed similar degrees of stenosis in the vessels supplying these segment pairs. In 13 of 32 cases, a perfusion defect and a slow washout rate were found in the contralateral segment.(ABSTRACT TRUNCATED AT 250 WORDS)

Collateral circulation in coronary artery disease

The coronary arteriograms and left ventriculograms of 202 consecutive patients were reviewed. All had at least 75% diameter reduction of 1 or more major coronary arteries. In 127 patients (63%), at least 1 major branch was totally occluded. Collateral circulation was seen in 125 of these 127 patients (190 of 192 totally occluded arteries). Of the 75 patients without total occlusion, only 2 with 99% (or near-total) occlusion had demonstrable collateral circulation (2 of 208 arteries). In no patient with 75 to 98% diameter narrowing was collateral circulation demonstrated (0 of 164 arteries). An analysis was made of the relation between left ventricular (LV) segmental wall motion and the quality of collateral circulation in 190 totally occluded arteries among 125 patients. Of 126 arteries with good collateral circulation, LV contraction was normal in 21%, hypokinetic in 48% and akinetic/dyskinetic in 29%. Of 64 arteries with poor collateral circulation, LV contraction was normal in 23%, hypokinetic in 55% and akinetic/dyskinetic in 20%. There was no statistically significant difference between the effect of good or poor collateral circulation on LV function. These data indicate that collateral circulation cannot be seen angiographically unless there is total or near-total occlusion, and that the presence of collateral circulation does not correlate with LV wall motion abnormalities, i.e., akinetic area, despite good collateral flow or normal wall motion despite absent or poor collateral flow.

Bacterial gene expression and biotechnology

This brief review article has been intended to give a few up-to-date examples of the dramatic impact that our knowledge of gene expression (especially bacterial gene expression) has had in the area of biotechnology. This area is in a state of such rapid growth that it has only been possible to present a limited overview of the subject matter. We have tried to illustrate our points with examples from work in which we have had some direct involvement. It should be apparent that continued increase in our understanding of gene expression should provide additional opportunities for expanded application of the new methodology.

Echocardiographic mimic of loculated pericardial effusion due to fluid accumulation in the subphrenic space

Images

[Actinomycosis of the abdominal wall--report of a case]

É relatado um caso de actinomicose de localização na parede abdominal.

A case of myocardial infarction in a patient with Werner's syndrome

We report on a case of premature atherosclerosis in a patient with short stature, dysmorphic features, mild diabetes mellitus, hypertriglyceridemia, Mönckeberg's sclerosis, and the general appearance of premature aging, compatible with the diagnosis of Werner's Syndrome. The patient was referred to us after suffering a myocardial infarction at the age of 26.

Validation of a computerized edge detection algorithm for quantitative two-dimensional echocardiography

An edge detection algorithm used in conjunction with digitized two-dimensional echocardiograms was applied to validate computerized two-dimensional echocardiographic (2DE) quantitation of cross-sectional areas of canine left ventricular chambers. Images were enhanced by space-time smoothing and dynamic range expansion, after which automatic edge detection was performed by convolving a Laplacian operator with the enhanced image. In an in vitro study of 29 myocardial slabs, computer-derived 2DE measurements of short-axis sections of the left ventricle were compared with manually derived 2DE data and validated against direct measurements of intraluminal areas of myocardial slabs. Correlations of both manually and computer-derived 2D echocardiograms vs direct measurements were equally satisfactory (r = .95 for both). Computer-derived measurements of perimeters tended to underestimate actual perimeters of the endocardial outlines of left ventricular sections. In 13 closed-chest anesthetized dogs, manually and computer-derived left ventricular short-axis areas measured by 2DE techniques showed a good correlation at both end-diastole (r = .91) and end-systole (r = .92). Left ventricular volumes reconstructed from 2DE images were compared with angiographically determined volumes. The computer-enhanced 2DE method correlated against angiography, with r = .93 for end-diastolic and r = .93 for end-systolic volumes. Left ventricular volume correlations between manually and computer-derived 2D echocardiograms were satisfactory, with r = .87 for end-diastole and r = .87 for end systole. We conclude that computerized enhancement and edge detection of 2D echocardiograms obtained in dogs provided accurate analysis of actual left ventricular cross-sectional areas and left ventricular volumes.

Analysis of the degree of pulmonary thallium washout after exercise in patients with coronary artery disease

An abnormal increase in pulmonary thallium activity may be visualized on post-stress thallium images in patients with coronary artery disease. Because this increased pulmonary thallium activity usually disappears by the time of redistribution imaging, this study was designed to assess whether measurement of the degree of pulmonary thallium washout between stress and redistribution might improve the detection of increased pulmonary thallium activity in patients with coronary artery disease. Quantitative analysis revealed abnormal (that is, greater than 2 standard deviations of normal values) pulmonary thallium washouts in 59 (64%) of 92 patients with coronary artery disease, but in only 2 (25%) of 8 subjects with angiographically normal arteries (p less than 0.06). By comparison, the visual analysis of pulmonary thallium washout and use of initial pulmonary to myocardial thallium ratio were significantly (p less than 0.05) less sensitive in detecting abnormality in patients with coronary artery disease. Abnormal pulmonary thallium washout was related to both the anatomic extent and functional severity of disease: it occurred with greatest frequency in patients with multivessel disease and in those with exercise-induced left ventricular dysfunction (p less than 0.005). When added to the quantitative analysis of myocardial scintigraphy, the analysis of pulmonary thallium washout increased the detection of coronary artery disease from 84 to 93% (p less than 0.05), but the sample size was too small to assess specificity. Thus, the analysis of pulmonary thallium washout is a useful diagnostic variable because it: 1) provides an objective measurement of abnormal pulmonary thallium activity and is more sensitive than other methods; 2) correlates with both the extent of coronary artery disease and the degree of exercise-induced left ventricular dysfunction, and 3) improves the sensitivity of quantitative myocardial thallium scintigraphy to detect the presence of coronary artery disease.

Clinical evaluation of seven-pinhole tomography for the detection and localization of coronary artery disease: comparison with planar imaging using quantitative analysis of myocardial thallium-201 distribution and washout after exercise

The development of quantitative techniques to assist in the analysis of planar thallium-201 stress-redistribution scintigrams has led to improved abilities of this modality to detect the presence of and to localize significant coronary artery disease (CAD). This fact has encouraged the reevaluation of its capabilities relative to other types of scintigraphic data collection, including seven-pinhole tomography. We have undertaken a comparison of planar scintigraphy and seven-pinhole tomography to detect in 40 exercised patients (23 with angiographically demonstrated CAD, eight with normal coronary angiograms, and nine with less than or equal to 1% likelihood of having CAD) the presence of significant CAD and to localize it correctly to an individual coronary artery. Emphasis was placed on similar imaging conditions and on analysis of images by the same quantitative program of TI-201 distribution and washout. Both techniques were found to be highly sensitive and specific for disease detection and localization. Importantly, seven-pinhole tomography did not significantly improve results.

Determination of cardiac output and ejection fraction with the dual cardiac probe

Cardiac output and left ventricular ejection fraction were determined noninvasively at the bedside in 26 patients by using a dual scintillation probe. The probe is a nonimaging detector that records a high frequency time-activity curve of the passage of an intravenously injected radioactive bolus through the heart. Results were correlated with ejection fraction measured by biplane cineangiography (r = 0.80) and cardiac output determined by green dye dilution (R = 0.86). It is concluded that the dual probe provides an accurate noninvasive means of measuring these parameters, and that it may be particularly applicable to serial measurements in patients in the intensive care unit.

Cascade control of Escherichia coli glutamine synthetase. Purification and properties of PII uridylyltransferase and uridylyl-removing enzyme

Uridylyltransferase, a component of the covalent modification cascade system that controls glutamine synthetase activity in Escherichia coli, has been purified to apparent homogeneity. The purification was facilitated by the use of an E. coli strain which carries multiple copies of a ColE1-hybrid plasmid containing the glnD gene that encodes uridylyltransferase and which overproduces its synthesis by 25-fold. Gel electrophoresis and high pressure liquid chromatography studies show that the native enzyme is a single polypeptide chain of Mr = 95,000 +/- 5,000. The purified enzyme catalyzes the uridylylation as well as the deuridylylation of the regulatory protein PII, demonstrating that a single bifunctional enzyme is involved in the covalent interconversion of PII. Gel filtration studies indicate that the enzyme undergoes slow irreversible aggregation during most steps of purification with a concomitant loss of activity.

Mechanism of phage-induced lysis in pneumococci

Earlier studies have suggested the possible role of host autolytic enzyme in the release of progeny phage from Dp-1 infected pneumococci. Several new experiments described here reinforce this notion. Specifically, the resistance of an autolysis-defective mutant to infection at low phage to cell ratios could be eliminated by prior 'coating' of the host bacteria with pneumococcal autolysin isolated from wild-type cells. Similar, productive infection was also possible by lowering the temperature of incubation to 30 degrees C, a condition that leads to a partial activation of the thermosensitive residual autolysin in the mutant cells. Other experiments, however, clearly indicate the role of the newly discovered phage-associated lysin (PAL), reported in the accompanying communication, in bacteriophage release and culture lysis; specifically, lysis was stimulated by reducing agents and inhibited by cardiolipin. It seems that both the host-related and the PAL activities are involved with Dp-1 induced lysis of pneumococci.

A phage-associated murein hydrolase in Streptococcus pneumoniae infected with bacteriophage Dp-1

A phage-associated murein hydrolase activity capable of degrading pneumococcal cell walls was isolated and purified to homogeneity from the phage-induced lysate of an autolysis-defective pneumococcal mutant infected with the bacteriophage Dp-1. Some properties of the enzyme resembled those of the wild-type (host) pneumococcal murein hydrolase: cell walls prepared from ethanolamine-grown pneumococci were resistant to the enzyme; the activity was inhibited by the Forssman antigen and was sensitive to proteolytic enzymes. The phage-associated enzyme was not inhibited by antiserum prepared against the purified pneumococcal murein hydrolase; the activity was stimulated by reducing agents and was partially inhibited by cardiolipin. The subunit molecular weight of the phage-associated enzyme was somewhat smaller (31 000) than that of the pneumococcal hydrolase (35 000). This appears to be the first description of a phage-associated murein hydrolase activity in pneumococci.

D-homoandrostanes. 4. The incubation of some D-homo-5 alpha-androstanes with Rhizopus nigricans

Nine dioxygenated D-homoandrostanes were incubated with Rhizopus nigricans to investigate the effect of D-ring modification on microbiological hydroxylation. Structure determination of the products by NMR spectroscopy, and in certain cases independent synthesis of their oxidised products, showed that in contrast to 5 alpha-androstanes the majority of the compounds were hydroxylated in the "reverse" mode, and only D-homo-5 alpha-androstane-3,17-dione was hydroxylated in the "normal" mode to any extent. Stereospecific ring D-hydroxylation at C(17 alpha) was observed for both D-homo-5 alpha-androstane-3,6- and 3,7-diones.

The noninvasive diagnosis of coronary artery disease in patients with left bundle-branch block

The prognosis in patients with left bundle-branch block (LBBB) is related primarily to the presence or absence of underlying cardiac disease. Because coronary artery disease (CAD) is the most common underlying disease found in these patients, it would be desirable, in the presence of LBBB, to have a noninvasive method of differentiating between patients with and without CAD. We reviewed our experience in patients with LBBB who had undergone coronary arteriography with regard to electrocardiographic (ECG) stress testing, exercise radionuclide ventriculography (RNV), and exercise thallium scintigraphy; we also reviewed their clinical histories. A clinical history of typical angina pectoris was specific for CAD, a false-positive history being present in only one of 12 patients without CAD. The frequency of a positive ECG ST response to exercise was equal in patients with and without CAD. False-positive ejection fraction and wall-motion responses to exercise were frequent by RNV. A modification of the usual RNV criteria for positivity improved specificity but resulted in poor sensitivity for CAD. False-positive thallium study results also were. frequent in these patients. The perfusion defects usually involved the ventricular septum; the inferior and posterior walls were involved only in patients with CAD. We conclude that the usual noninvasive diagnostic tests for CAD are of limited value in patients with LBBB.

Noninvasive assessment of the Ionescu-Shiley pericardial xenograft in the mitral position: preliminary experience

To establish noninvasive criteria for assessment of the Ionescu-Shiley pericardial xenograft in the mitral position, 29 patients with a normally functioning bioprosthesis were studied with m-mode echocardiography and phonocardiography. Two-dimensional echocardiograms were also obtained in ten of the patients. Although two-dimensional echocardiography provided simultaneous visualization of a greater number of stents and leaflets than the m-mode technique, the superior resolution of m-mode ultrasound permitted more detailed analyses of the xenograft's motion patterns. The anterior leaflet, recorded in all patients, had an average excursion of 1.2 +/- 0.22 cm. Leaflet thickness measured 4 mm or less. Coarse diastolic vibration of the anterior leaflet was recorded in two patients in the absence of both aortic insufficiency and prosthesis dysfunction. Ultrasonic estimates of prosthesis height and orifice diameter did not correlate with micrometer measurements, possibly due to the limited resolution of pulsed ultrasound in the presence of a highly reflective substance. Opening and closing of the pericardial leaflets were associated with the production of high frequency vibrations on the phonocardiogram. The potential usefulness and limitations of echocardiography for evaluating the function of bioprosthetic valves are discussed.

Choline-containing bacteriophage receptors in Streptococcus pneumoniae

Choline-containing teichoic acid seems to be essential for the adsorption of bacteriophage Dp-1 to pneumococci. This conclusion is based on the following observations: In contrast to pneumococci grown in choline-containing medium, cells grown in medium containing ethanolamine or other submethylated aminoalcohols instead of choline were found to be resistant to infection by Dp-1. Live choline-grown bacteria and heat- or UV-inactivated cells and purified cell walls prepared from these cells were capable of adsorbing phage Dp-1; ethanolamine-grown pneumococci or cell wall preparations were unable to do so. Adsorption of Dp-1 to choline-containing cell walls was competitively inhibited by phosphorylcholine and by several choline-containing soluble cell surface components, such as the Forssman antigen and the teichoic acid-glycan complexes formed by autolytic cell wall degradation. Cell walls prepared from pneumococci grown in ethanolamine or phosphorylethanolamine were inactive. Electron microscopic studies with pneumococci that had segments of choline-containing cell wall material amid ethanolamine-containing regions indicated that the Dp-1 phage particles adsorbed exclusively to the choline-containing surface areas. We suggest that the choline residues of the pneumococcal teichoic acid are essential components of the Dp-1 phage receptors in this bacterium.

Post-exercise potentiation of wall motion to identify myocardial viability

Resting left ventricular wall motion abnormalities may represent myocardial scars or areas of viable muscle which are ischemic and may thus benefit from revascularization surgery. Improvement in wall motion in the 3-6 minute post-exercise recovery period as compared to the resting state was investigated as a possible criterion to predict myocardial viability in 168 patients with coronary artery disease. Of 125 patients with abnormal resting wall motion, 14 of 14 who improved regional function post-exercise also improved following coronary bypass surgery. However, wall motion improved postoperatively in an additional 55 patients who had not demonstrated post-exercise improvement. An increase in ejection fraction post-exercise occurred in patients with coronary disease as well as an additional group of 24 normal subjects. Thus in the post-exercise period, improvement in resting wall motion is a highly specific but insensitive predictor of myocardial viability.

Initial diastolic indentation of the mitral valve in aortic insufficiency

An abnormal diastolic indentation of the mitral valve has been noted on short-axis two-dimensional echocardiograms in patients with aortic insufficiency. In order to assess the clinical usefulness of this finding, we reviewed the echocardiograms of 18 patients with this lesion who had undergone cineaortography. Results were compared with those of a control group of 100 patients. Initial diastolic indentation of the anterior mitral leaflet occurred in 8 of 12 patients with 3+ to 4+ aortic insufficiency. None of the patients with lesser regurgitation and no patients from the control group demonstrated this pattern. The presence of this abnormality appears to be a specific indicator of critical aortic insufficiency.

Premature closure of prosthetic mitral valves as a consequence of gravity

To determine the influence of gravity on premature closure of prosthetic mitral valves, we studied 17 patients in whom this phenomenon had been observed during routine examination. All patients were in atrial fibrillation and none had aortic incompetence. Patients were studied in multiple positions by means of simultaneous echocardiography, phonocardiography, and cinefluoroscopy. In all patients premature closure was observed when the atrial side of the prosthesis was below the ventricular side, resulting in a downward motion of the occluder inside the valve cage. When patients were studied in positions in which the atrial side of the valve was higher that the ventricular side, premature closure never occurred, even during extremely prolonged diastolic periods. Since minor positional changes, which were found to determine whether premature closure occurred or not, are unlikely to produce significant alterations in pressure and flow across the mitral orifice during diastole, we conclude that position-dependent premature closure of prosthetic mitral valves in patients with atrial fibrillation is best explained by the effect of gravity on the prosthetic occluder. Examination of such patients in multiple positions should be helpful in distinguishing premature valve closure caused by aortic regurgitation from gravity-related presystolic closure. Inability to produce premature closure in patients in whom it had previously been demonstrated in the presence of similar R-R intervals may even prove useful in diagnosing new orifice obstruction.

Skin window immune response to normal human IgG in patients with rheumatoid arthritis and acute poststreptococcal glomerulonephritis

The skin window technic was utilized to determine the reactivity of patients with rheumatoid arthritis (RA) and acute poststreptococcal glomerulonephritis (APSGN) to human IgG (H-IgG). The response to H-IgG was compared in nine patients with RA, 20 patients with APSGN, and 10 normal individuals. All subjects were tested concomitantly with the saline solution used as solvent for H-IgG. The normal controls and five patients were challenged, in addition, with diphtheria-tetanus-pertussis antigen (DPT) to which they had previous prophylactic exposure. The following results were obtained: 1) Four patients with RA and nine patients with APSGN responded with increased lymphocyte migration (more than 2 SD above the normal mean level) at nine and 12 hours. 2) The mean estimated immunogenic lymphocytosis (calculated subtracting the lymphocyte counts of the saline skin windows) of both patient groups was significantly higher than that of controls at the same time intervals. 3) The response of normal individuals and patients to DPT was comparable in time of appearance and intensity to the response of patients to H-IgG. Our studies that patients with RA and APSGN respond to H-IgG in a manner comparable to that observed with a known antigenic stimulus and support a clinical role for antiglobulin reactivity.

Real time computerization of two-dimensional echocardiography

A computerized system was developed for real time acquisition, enhanced processing, analysis, and display of cross-sectional images of the left ventricle derived by two-dimensional echocardiography (2DE). The new methodology couples a standard medical imaging computer system to the video output of any current 2DE unit, uses a 128 x 128 or 64 x 64 matrix window and stores the real time 30 frames/sec digitized images on a magnetic disk. Computerized beat-to-beat and frame-by-frame processing employs space-time smoothing the automatic detection of endocardial interfaces by standard threshold and second derivative techniques. Multiple views are displayed in real time with 256 levels of gray and color. The methodology was used to analyze and graphically display frame-by-frame changes throughout the cardiac cycle. In addition, regional wall motion and thickness were analyzed in 12 sectors of individual cross-sections using a standardized angular subdivision originating at the center of area and indexed by an external reference point. An algorithm was developed to correct cross-sectional interference definition from the commonly used trailing-to-leading edge to the more valid leading-to-leading outline technique. Computerized analysis of spatial and temporal variations of cardiac contraction were demonstrated in several clinical and experimental applications, including bicycle exercise testing, investigation of acute myocardial infarction, and assessment of interventions. Initial evaluation indicates that the new real time computerized digital acquisition and data analysis represents a major advances toward quantitation of left ventricular function using 2DE.

Space/time quantitation of thallium-201 myocardial scintigraphy

A comprehensive method is described for quantitation of the spatial distribution of TI-201 in the myocardium and its changes with time. The method, applied here to 51 patients, uses bilinear interpolative background subtraction to compensate for tissue crosstalk, and circumferential profiles to quantitate the relative radionuclide activity in the myocardium as an angular function with origin at the center of the left-ventricular cavity. In addition, washout circumferential profiles are calculated as percent washout from the stress circumferential profiles. Abnormal thallium distribution or washout is identified by automatic computer comparison of each patient's profiles with the corresponding limits of normal profiles, determined from the pooled profiles of 31 normal patients. In these 31, the computer output was normal in all cases. In 20 patients with angiographically documented coronary artery disease, 19 were determined to be abnormal by this method. This new computerized treatment provides accurate objective assessment of the presence of coronary artery disease.

Bacteriophages of Streptococcus pneumoniae

Properties of some of the bacteriophages of Streptococcus pneumoniae are reviewed. Studies with these phages have yielded several interesting observations and results. (1) A simple transfection system that uses DNA of mature pneumococcal phages was developed; results of studies utilizing this system have determined the intracellular events that followed infection with these bacteriophages. (2) Some pneumococcal phages have shown dependence on the bacterial (host) murein hydrolase for the liberation of phage progeny. (3) Phage Dp-1 has been described as the first lipid-containing phage with a gram-positive bacterial host. (4) Phage Cp-1, a recently isolated phage of unique morphology, promises to become a useful phage for studies of the genetic of the pneumococcus.

Respiratory variation in Frank vectorcardiography and echocardiography in children

Forty pediatric patients underwent echocardiographic and Frank vectorcardiographic studies during normal respiration. The right ventricular minor axis (RVEDD) increased significantly with inspiration (p less than 0.005), while the left ventricular minor axis did not significantly change. The distance from the anterior chest wall to the center of the left ventricle did significantly increase with inspiration (p less than 0.005). Some vectorcardiographic parameters changed with inspiration, also. Both the maximal spatial vector to the left (MSVL) and the X to the left (X-L) significantly decreased with inspiration. Although the average magnitude of these changes was small (10-15%), there was wide variation. Five of twenty-one patients with left ventricular hypertrophy during expiration had a clearly normal Frank VCG during inspiration. It is suggested that phases of respiration should be monitored when evaluating the Frank VCG in pediatric patients.