Changes in T-lymphocyte subpopulations in patients splenectomized for trauma

Surface markers of peripheral mononuclear cells, using a monoclonal antibody, were characterized, and the serum immunoglobulins (IgG, IgM, IgA) as well as complement proteins (C3, C4) were determined in 20 adult patients with splenectomy because of trauma. A similar analysis was performed on 20 healthy individuals and the results compared. The average interval from splenectomy to testing was two years. The percentages of total T-cells (CD3), T-helper cells (CD4), and T-suppressor cells (CD8) were reduced in all subjects the splenectomized, but the results were statistically significant only for the CD4 cells (p less than 0.01). The proportion of B-cells (OKB7) showed no difference in either group. However, the ratio of CD4/CD8 cells was significantly decreased in splenectomized subjects (p less than 0.05). Measurement of serum immunoglobulins (IgG, IgA, IgM) and complement proteins (C3, C4) revealed no significant differences between the two groups. These data suggest that healthy adults undergoing splenectomy for trauma have a specific and persistent immunological deficit. Our results suggest that a more cautious and conservative attitude toward the splenic trauma should be adopted.

Frequency and severity of mitral regurgitation one year after balloon mitral valvuloplasty

Mitral regurgitation (MR) was evaluated by Doppler echocardiography in 59 patients with mitral stenosis before, immediately after and 1 year after balloon mitral valvuloplasty (BMV). The severity of MR was graded on a scale from 1+ to 4+. Echocardiographic and hemodynamic variables were analyzed to study the potential factor(s) that might predict the long-term persistence of MR. Echocardiographic variables were mitral valve thickness and motion, subvalvular change, left atrial dimension, commissural calcification and effective balloon/mitral anular diameters. Hemodynamic variables were mitral pressure gradient, pulmonary arterial pressure, ejection fraction, mitral valve area index, age, gender and cardiac rhythm. Mitral valve area index increased from 0.9 +/- 0.5 to 1.5 +/- 0.8 cm2/m2 immediately after BMW, and to 1.4 +/- 0.3 cm2/m2 at 1 year follow-up (p less than 0.01). Immediately after BMV, MR grading did not change in 30 patients (51%), increased by 1+ in 23 patients (39%), by 2+ in 2 patients (3.3%) and by 3+ in 2 patients (3.3%), and decreased by 1+ in 2 others. At 1-year follow-up, only 1 patient with severe MR required valve replacement. Fifty-one patients (88%) had no change in the extent of MR (less than or equal to 1+) and 6 patients (10%) had a 1-grade decrease in their MR; only 1 patient had a 1-grade increase in MR. No clinical or hemodynamic variables or morphologic characteristics of the mitral valve could predict the development of significant MR after BMV. It is concluded that an increment in MR severity less than or equal to 2+ is frequently seen after BMV.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of low levels of the stereoisomers of leucovorin and 5-methyltetrahydrofolate in plasma using a coupled chiral-achiral high-performance liquid chromatographic system with post-chiral column peak compression

A method for the determination of low levels of the stereoisomers of leucovorin and 5-methyltetrahydrofolate has been developed and validated. The assay involved initial chromatography on a bovine serum albumin (BSA)-based high-performance liquid chromatography chiral stationary phase (CSP) followed by post-column peak compression and elution on two C18 columns. In this manner, the poor efficiency of the BSA-CSP was overcome and sub-microgram quantities of the target solutes could be detected. The BSA-CSP separated the leucovorin and 5-methyletrahydrofolate from interfering plasma components and from each other and achieved the stereochemical resolution of the diastereomeric (6S)-and (6R)-leucovorin. The eluent containing (6S)-leucovorin was directed onto one C18 column and the eluent containing (6R)-leucovorin and 5-methyltetrahydrofolate was directed onto the other. This was followed by sequential rapid gradient elution of the target compounds from the respective C18 columns. The method was validated for plasma levels ranging from 15 to 500 ng/ml and was able to detect leucovorin concentrations of as low as 5 ng/ml.

[Cavernous hemangioma of the heart: report of a case]

Cavernous hemangioma of the heart is a very rare disease. A 57-year-old male patient was admitted due to frequent onset of dull chest pain, which had been occurring for about 1 year. The pain was not related to exercise and was not relieved with nitroglycerin. On echocardiographic examination, a tumor was shown in the outflow tract of the right ventricle and was confirmed with computer tomography. He underwent open heart surgery for resection of the tumor. After a median sternotomy and opening of the pericardial cavity, a reddish-brown-colored tumor, 3 cm in diameter, was found protruding from the epicardial layer of the right ventricular outflow tract. The tumor involved all layers of the ventricle and could be resected only with the help of the cardiopulmonary bypass technique. The defect in the right ventricle was repaired with a woven dacron patch. The patient recovered without incident after the operation, and experienced no chest pain during 7 months of follow-up. Histology showed it to be a cavernous hemangioma.

Correlation of orbital computed tomography and antibodies in patients with hyperthyroid Graves' disease

The purpose of this study was to elucidate the incidence of orbital changes in computed tomography, and the relationships of orbital changes with eye-muscle antibody (EMAb), thyrotrophin-binding inhibitor immunoglobulin (TBII), antithyroglobulin antibody (TgAb) and anti-thyroid microsomal antibody (MsAb), in 55 consecutive patients with hyperthyroid Graves' disease. EMAb was demonstrated by an immunoperoxidase technique. The results showed that the prevalence of orbital fat increase, extraocular muscle enlargement, lacrimal gland enlargement and optic nerve swelling were 54.5, 41.8, 21.8 and 16.5% respectively. There were 32.7% of patients without any orbital changes. The patients with extraocular muscle enlargement, lacrimal gland enlargement and optic nerve swelling had higher titres of EMAb than the patients without these orbital changes. The patients with lacrimal gland enlargement had a lower TBII index than those without. There was no difference in TgAb or MsAb between the patients with extraocular muscle enlargement, lacrimal gland enlargement, optic nerve swelling or orbital fat increase and those patients without these orbital changes. The patients with extraocular muscle enlargement, optic nerve swelling and orbital fat increase had a higher degree of exophthalmos than the patients without these orbital changes. EMAb was negatively correlated with TBII. However, there was no correlation between EMAb and TgAb or MsAb. The degree of exophthalmos was positively correlated with EMAb and negatively correlated with age. There was no correlation between exophthalmos and TBII, TgAb or MsAb. In conclusion, although the pathogenesis of orbital changes and hyperthyroidism is different, a close link between these two entities is suggested by the high incidence of orbital changes in hyperthyroid Graves' disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence from X-ray absorption fine structure spectroscopy for significant differences in the structure of concanavalin A in solution and in the crystal

We have used X-ray absorption fine structure spectroscopy (XAFS) to study and compare the structure of concanavalin A in crystals and in aqueous solution. Significant differences were found between crystal and solution in the configuration of the transition-metal site of the protein. The metal has six ligands in solution but only five in the crystal. The ligand bond lengths are shorter in the crystal than in solution. The vibrational disorder in the crystal and possibly the corresponding bond length show a negative temperature dependence whereas in solution they vary normally with temperature. The anomalous temperature dependence in the crystal suggests that as the temperature decreases the protein molecules are subject to additional stresses, which are transmitted as a tensile stress at the metal site leading to distorted geometry and lengthening and weakening of metal-ligand bonds.

Usefulness of echocardiography in the prediction of early results of catheter balloon mitral valvuloplasty

Catheter balloon mitral valvuloplasty (BMV) was performed in 50 patients and 32 of them undergoing BMV with double balloon technique were studied to evaluate the usefulness of echocardiography in the prediction of early results of BMV. Five echocardiographic variables including mitral valve motion, mitral valve thickness, subvalvular change, commissural calcification and left atrial dimension were evaluated. Each variable was divided into mild, moderate and severe subgroups. Before valvuloplasty there were no differences in mitral valve area among any subgroup for any variable. After valvuloplasty, variables associated with a greater increase in mitral valve area from mild and moderate subgroups than from severe subgroup included mitral valve motion, mitral valve thickness, and subvalvular change, but not commissural calcification or left atrial dimension. We scored the former 3 variables as 0, 1 and 2 points in the mild, moderate and severe subgroups, respectively. The sums of individual scores in these 3 variables were further divided into 3 groups: 12 patients had a lower score (less than 2), 10 patients had a score of 3-4 and 10 patients had a higher score (greater than 5). Patients with lower scores tended to have greater increases in mitral valve areas after valvuloplasty than those with higher scores. Thus, mitral valve motion, mitral valve thickness and subvalvular change may be useful to predict a greater increase in mitral valve area after valvuloplasty. A lower score of echocardiographic variables anticipates successful balloon mitral valvuloplasty, which may be helpful in patient selection.

Inaccuracy of Doppler estimates of pulmonary artery pressure using pulmonary flow acceleration time

Pulsed Doppler echocardiography was used to estimate mean pulmonary artery pressure (PAP), mean pulmonary artery wedge pressure PAWP) and the changes in PAP and PAWP following intervention in an unselected population composed of 60 patients undergoing routine diagnostic cardiac catheterization. Simultaneous Doppler and strain gauge manometry recordings of PAP and PAWP were interpreted by independent observers in a blinded fashion. A first set of measurements was obtained before left ventricular angiography and a second soon after the injection of contrast dye. The mean Doppler PAP and PAWP were derived from acceleration time and calculated using previously published regression equations: PAP = -0.45 x AcT + 79, PAWP = 57 - 0.39 x AcT. At rest, PAP measurements by strain gauge manometry ranged from 13 to 45 mmHg with a mean of 24 +/- 10 (one standard deviation); PAWP ranged from 2 to 40 mmHg with a mean of 15 +/- 6. Following left ventricular angiography, the PAP ranged from 18 to 50 mmHg with a mean of 29 +/- 7; PAWP ranged from 6 to 45 mmHg with a mean of 20 +/- 7. The values obtained by pulsed Doppler before and after intervention correlated poorly with those obtained by strain gauge manometry (r = 0.09 and 0.26 for PAP; r = 0.03 and 0.25 for PAWP).(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of early myocardial tissue changes in acute canine myocardial infarction by ultrasonic tissue characterization methods

To determine the time after left anterior descending (LAD) artery occlusion in which myocardial texture changes first occur, two-dimensional echocardiograms on five sham operated dogs and eight dogs before and after proximal LAD occlusion were performed. Serial two-dimensional echocardiograms were performed every 15 mins by placing a 5 MHz transducer directly on the chest wall. The dogs were sacrificed at the end of the study and the area of myocardial infarction was confirmed by triphenyltetrazolium chloride staining. The two-dimensional echocardiogram images were digitized. The mean pixel intensity +/- SD in the area of myocardial infarction (region of asynergy) and a normally moving area (control region) equidistant from the transducer were calculated; thus, each dog served as its own control. In sham operated dogs, no significant changes in mean pixel intensity, skewness or kurtosis were observed. There was a significant increase (P less than 0.01) in mean pixel intensity in the infarcted regions (anteroseptal) compared to values obtained in the normally moving (lateral) regions at 30 mins (mean pixel intensity 25.2 +/- 2.1 versus 23.0 +/- 0.7, P less than 0.05); this difference persisted at 45 mins (mean pixel intensity 25.8 +/- 0.9 versus 22.6 +/- 0.5, P less than 0.01), 60 mins (mean pixel intensity 27.2 +/- 1.4 versus 22.8 +/- 0.8, P less than 0.01), 90 mins (mean pixel intensity 28.6 +/- 1.6 versus 22.5 +/- 0.9, P less than 0.01) and 180 mins (mean pixel intensity 28.7 +/- 1.8 versus 21.3 +/- 1.4, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Minimal requirement of effective dilation diameter of balloon(s) in percutaneous transluminal mitral valvotomy

40 patients are included to study the minimal requirement of effective dilation diameter of balloon(s) in performing percutaneous transluminal mitral valvotomy (PTMV) to obtain good hemodynamic and long-term follow-up consequences. The patients are divided into 2 groups depending on the ratio of effective dilation diameter of balloon(s) (determined by calculating the cross-sectional area of the oval enveloping the one or two balloons and then taking the diameter of the circle with the same area) to mitral annular diameter (determined by 2-dimensional echocardiography) (Balloon-Mitral Anular Ratio, BMAR). BMAR in group 1 may be equal to or greater than 0.80 or 0.90, BMAR in group 2 may be less than 0.80 or 0.90. From the careful analysis, the statistically significant immediate hemodynamic improvement, e.g. the reduction of trans-valvular pressure gradient, left atrial pressure, pulmonary artery systolic pressure, the increase of mitral valve area, can be obtained even BMAR is less than 0.80. However, the increase of stroke volume index after PTMV can only be obtained with the BMAR equal to or greater than 0.80. The long-term improvement, determined by greater increment of exercise duration, is also only obtained if the BMAR equal to or greater than 0.80 at PTMV. Therefore, we conclude that to obtain the adequate and satisfactory immediate hemodynamic and long-term follow-up results of PTMV, the BMAR must exceed 0.80.

Acute primidone intoxication: report of a case

A case of acute primidone intoxication, due to overdose, was evaluated at National Taiwan University Hospital. Serial assessment of the clinical manifestations, electroencephalograms and serum levels of primidone and phenobarbital were made. From these data, we conclude that the toxic effects, such as depression of the central nervous system and dysequilibrium, are due mostly to primidone itself, rather than its metabolite, phenobarbital.

[Effect of trace elements in traditional Chinese medicine in the light of Chinese medicinal theory]

This paper presents a survey of the study on the relationship between trace elements and effect of treatment in traditional Chinese medicine. The authors have made a review in the light of Chinese medicinal theory.

Ultrasonic tissue characterization of acute canine myocardial infarction

This study assessed changes in left ventricular texture on two-dimensional (2-D) echocardiography after experimental myocardial infarction. In 13 dogs, the left anterior descending coronary artery (LAD) was occluded for 3 h, followed by 1 h of reperfusion and sacrifice. Two-dimensional echocardiography was performed pre-LAD occlusion, 3 h post occlusion and 1 h after reperfusion by placing a 5 MHz transducer on the chest wall. After sacrifice, triphenyltetrazolium chloride staining was performed on 1 cm thick left ventricular cross-sectional slices. Five dogs served as controls (shams). Two-dimensional echocardiograms were digitized and in the region of left ventricular asynergy (area of myocardial infarction), and adjacent normal area, the mean pixel intensities (+/- SD) were calculated. There was no significant change in the mean pixel intensity from 0 through 4 h in the lateral (22.8 +/- 1.3 and 23.4 +/- 1.8) and anteroseptal (23.2 +/- 1.9 and 22.6 +/- 1.9) regions in sham operated dogs. In dogs undergoing LAD occlusion, the mean pixel intensity from the pre- to post occlusion period showed no significant change in the lateral (normal) area, 24.4 +/- 2.7 versus 24.7 +/- 2.9. In the area of wall motion abnormality (area of myocardial infarction) the mean pixel intensity increased from 25.4 +/- 2.7 to 33.7 +/- 4.5, P less than 0.01. There was no significant change in the mean pixel intensity between the 3 h post occlusion and post reperfusion period in either the lateral (normal) or anteroseptal areas of the left ventricle. The area of left ventricular asynergy corresponded to the area of myocardial infarction on triphenyltetrazolium chloride stain.(ABSTRACT TRUNCATED AT 250 WORDS)

Platelet activation in patients with mitral valve prolapse

An increased frequency of thromboembolic events in patients with mitral valve prolapse has been demonstrated. It has been suggested that this association may be related to increased systemic platelet activity. Beta-thromboglobulin (BTG) is a platelet specific protein secreted during the platelet release reaction, with BTG levels reflecting ongoing platelet activation. Plasma BTG levels were measured in 14 normal volunteers, 23 patients with mitral valve prolapse and nonthickened mitral leaflets (group 1) and 13 patients with mitral valve prolapse and thickened mitral leaflets (group 2). The BTG level was 8.1 +/- 4.6 ng/mL (mean +/- SD) in normal subjects, 9.6 +/- 5.5 ng/mL in the nonthickened mitral valve prolapse group and 10.0 +/- 5.7 ng/mL in thickened mitral valve prolapse group. There was no significant difference in the BTG levels between groups. Five patients with multiple valvular prolapse did not show elevation of BTG levels. The present study did not demonstrate increased BTG levels in neurologically asymptomatic mitral valve prolapse patients.

[Determination of berberine in Angong Niuhuang Wan by HPLC]

A normal phase liquid chromatographic method was developed for the determination of berberine-type alkaloids in rhizoma Coptidis and traditional Chinese medicine--Angong Niuhuang Wan. Experimental evidences indicate that a normal phase system of a silica column (3.9 x 250 mm) as stationary phase with an eluent of ethyl acetate-formic acid-ethanol (15:3:2) as mobile phase can separate excellently (R5 greater than 1.5) four berberine-type alkaloids in the samples tested. According to the results obtained with this method the percent content of berberine hydrochloride in some Angong Niuhuang Wan from different factories and different batches was 0.331-0.456% and the average recovery was 97.23%; coefficient of variation was 1.2%.

Orientation of carbon monoxide and structure-function relationship in carbonmonoxymyoglobin

Fourier transform infrared spectroscopy of the CO stretch bands in carbonmonoxymyoglobin (MbCO) reveals three major bands implying that MbCO exists in three major substates, A0, A1, and A3. After photolysis at low temperatures the CO is in the heme pocket, and the resulting CO stretch bands represent the B substates. Photoselection experiments determine the orientation of CO in the A (bound) and B (photolyzed) substates: Small fractions of MbCO are photolyzed at 10 K with linearly polarized light at 540 nm. The resulting linear dichroism in the A and B IR bands yields the tilt angle between the heme normal and CO. The average angles are as follows: alpha (A0) = 15 degrees +/- 3 degrees; alpha (A1) = 28 degrees +/- 2 degrees, and alpha (A3) = 33 degrees +/- 4 degrees. The A bands are inhomogeneously broadened; the angle alpha shows a wavenumber dependence within the A bands. The wavenumber dependence is interpreted as a distribution of the tilt angle within the individually inhomogeneous A substates, thus providing a structural parameter to characterize the distribution of the conformational substates. The B substates exhibit no induced linear dichroism; in the photolyzed substates the ligand is randomly oriented with respect to the heme plane. The present results together with earlier data on static and kinetic properties of CO binding to Mb establish relations among spectroscopic, structural, energetic, and functional parameters.

Comparison of Doppler echocardiographic and hemodynamic indexes of left ventricular diastolic properties in coronary artery disease

Transmitral flow velocity was measured by Doppler echocardiography in 15 patients with coronary artery disease simultaneously with high-fidelity recording of left ventricular pressure. Doppler echocardiographic recordings were also performed in 14 age- and heart rate-matched normal subjects. Statistically significant differences (p less than 0.05) in acceleration half-time (55.3 +/- 8.2 vs 70.4 +/- 14.9 ms), deceleration half-time (83.1 +/- 17.9 vs 109.5 +/- 18.1 ms), deceleration rate (4.9 +/- 0.9 vs 3.1 +/- 0.9 m/s2), peak velocity of early diastolic left ventricular inflow (E wave) (0.78 +/- 0.13 vs 0.61 +/- 0.13 m/s) and A/E ratio (0.74 +/- 0.20 vs 0.98 +/- 0.31) between normal subjects and patients were noted. There was no significant difference in peak velocity of atrial systolic flow (A wave) between normal subjects and patients. Correlation between transmitral flow indexes and hemodynamic indexes of left ventricular diastolic properties were poor, with r values ranging from 0.02 to 0.65. Significant correlations between deceleration rate versus maximal isovolumic left ventricular pressure decrease (maximum -dP/dt) and A wave versus maximum -dP/dt (p less than 0.05) were found (0.53 and 0.65, respectively). Deceleration rate was the most sensitive index of isovolumic relaxation assessed by hemodynamic methods, whereas the A/E ratio was a poor indicator of hemodynamic measurements of isovolumic relaxation. An abnormal deceleration rate had 100% specificity for detecting abnormal maximum -dP/dt, while abnormal acceleration half-time, deceleration half-time and A/E ratio had 80% specificity for detecting abnormal time constant. The deceleration rate, acceleration half-time, deceleration half-time and A/E ratio had a predictive value of 60 to 100% for the detection of abnormal maximum -dP/dt and time constant.

Promotion of Mycoplasma pulmonis growth in rat tracheal organ cultures by ammonium chloride

During exacerbation of respiratory mycoplasmosis in rats by environmental ammonia, numbers of Mycoplasma pulmonis organisms in the respiratory tract are increased. To test whether or not exposure of respiratory epithelium to ammonia in vitro promotes growth of the organism, rat tracheal organ cultures were treated with 50 mM ammonium chloride, inoculated with M. pulmonis, and quantitatively cultured. After 48 hours, treated tracheas harbored almost 10 times more M. pulmonis colony-forming units than control tracheas. Cellular lesions in the epithelium of treated tracheas resembled those in the nasal passages of rats exposed to gaseous ammonia. To determine whether or not growth-modifying factors were released from tracheal epithelium exposed to ammonium chloride, M. pulmonis growth was assessed in medium collected from ammonium chloride-treated and control tracheas. Growth in medium from treated tracheas was greater than that in medium from untreated tracheas.

Deprotonation of tyrosines in bacteriorhodopsin as studied by Fourier transform infrared spectroscopy with deuterium and nitrate labeling

Fourier transform infrared (FTIR) difference spectra are presented for bacteriorhodopsin (BR) at low temperature. Previous FTIR measurements have identified several tyrosine residues that change their absorption characteristics between light-adapted BR and dark-adapted BR, or between intermediates K and M [Dollinger, G., Eisenstein, L., Lin, S.-L., Nakanishi, K., Odashima, K., & Termini, J. (1986) Methods Enzymol. 127, 649-662]. These changes were explained by protonation/deprotonation of tyrosine moieties and perturbation of the protein environment surrounding tyrosines. A tyrosine deprotonation was observed to occur between intermediates K and M. The present studies confine the deprotonation to being between intermediates L and M and show that no tyrosines undergo changes between the K and the L states. Evidence is presented that none of the tyrosines undergoing changes at low temperature can be assigned to tyrosine-64. The environmental changes of these tyrosines are discussed in relation to the proton pumping mechanism. Their spatial relation to the chromophore is also discussed. At least two tyrosines are suggested to reside close to the retinal binding site. The reactive groups of the nitrated tyrosine-64 are speculated to be remote from the Schiff base and the active tyrosines but can possibly interact sterically with the ionone ring of the retinal.

Remarriage after divorce: recent changes and demographic variations

Using data from US Bureau of the Census publications from the decennial censuses and the Bureau's Current Population Reports, the authors analyze remarriage in the US. Among adults who had ended their 1st marriage in divorce, about 3/4 of the elderly men and 2/3 of the elderly women in both 1970 and 1980 were found to be remarried. However, the general decline in remarriage at the younger ages during the 1970s was accentuated among those under 35 years old. Although the proportion remarried among women with graduate school training was the smallest, that proportion declined less during the 1970s than for women in any other educational level. In both 1970 and 1980, the proportion remarried was positively correlated with personal income for men but negatively for women. An estimated 2/3 of those who end their 1st marriage in divorce will eventually remarry while they have young children living with them. During the lifetime of women in their 2nd marriage after their 1st marriage ended in divorce, only 1/3 of their children are born after remarriage, whereas 2/3 are born before their 2nd marriages. During the 1970s, the proportion of currently divorced adults living alone or sharing the homes of relatives diminished, while the proportion living as cohabitants outside marriage rose substantially. It appears as if both the divorce rate and the remarriage rate are approaching a period of relative stability.

Disappearance of statin, a protein marker for non-proliferating and senescent cells, following serum-stimulated cell cycle entry

Statin, a protein of 57,000 D, is present in the nuclei of quiescent or senescent fibroblasts (Wang, E, J cell biol 100 (1985) 545), but is absent in their young replicating counterparts. Immunohistochemical survey of a variety of tissues demonstrates that the presence of statin is a marker for cells that are no longer involved in proliferation, i.e. those cells that are terminally differentiated. Statin expression was examined by immunofluorescence microscopy in serum-starved cultures whose replication had been reinitiated by raising the serum concentration from 0.5 to 10%. Prior to serum addition, more than 85% of the cells stained positively for statin. After stimulation with serum, the expression of statin disappeared rapidly within the first 12-14 h. On the other hand, an increase in the level of DNA synthesis, signifying entry into S phase, was observed initially at 18 h after serum stimulation, and reached maximal levels 6 h later. Immunoprecipitation of statin derived from cells harvested at different intervals after serum stimulation revealed that the level of statin synthesis was reduced by 4 h and was hardly detectable at 8 h. These results demonstrate that the synthesis of statin occurs primarily when cells are in a quiescent state, and declines rapidly when cells are induced to proliferate; this decline precedes the transition from G1 to S phase.

Fourier transform infrared difference spectroscopy of bacteriorhodopsin and its photoproducts regenerated with deuterated tyrosine

Fourier transform infrared (FTIR) difference spectroscopy has been used to detect the vibrational modes due to tyrosine residues in the protein that change in position or intensity between light-adapted bacteriorhodopsin (LA) and other species, namely, the K and M intermediates and dark-adapted bacteriorhodopsin (DA). To aid in the identification of the bands that change in these various species, the FTIR spectra of the free amino acids Tyr-d0, Tyr-d2 (2H at positions ortho to OH), and Tyr-d4 (2H at positions ortho and meta to OH) were measured in H2O and D2O at low and high pH. The characteristic frequencies of the Tyr species obtained in this manner were then used to identify the changes in protonation state of the tyrosine residues in the various bacteriorhodopsin species. The two diagnostically most useful bands were the approximately 1480-cm-1 band of Tyr(OH)-d2 and the approximately 1277-cm-1 band of Tyr(O-)-d0. Mainly by observing the appearance or disappearance of these bands in the difference spectra of pigments incorporating the tyrosine isotopes, it was possible to identify the following: in LA, one tyrosine and one tyrosinate; in the K intermediate, two tyrosines; in the M intermediate, one tyrosine and one tyrosinate; and in DA, two tyrosines. Since these residues were observed in the difference spectra K/LA, M/LA, and DA/LA, they represent the tyrosine or tyrosinate groups that most likely undergo changes in protonation state due to the conversions. These changes are most likely linked to the proton translocation process of bacteriorhodopsin.

Concomitant enhancement of a cytoskeleton-associated 76,000-dalton protein and inhibition of fluid-phase pinocytosis by interferon-alpha in Fujinami sarcoma virus-transformed rat 3Y1 cells

Addition of rat interferon-alpha (IFN-alpha) to Fujinami sarcoma virus-transformed rat 3Y1 cells progressively inhibited fluid-phase pinocytosis [10% inhibition at 3 h; maximal (60%) inhibition by 12 h]. Electrophoretic analysis of the cytoskeletal fraction from cultures exposed to IFN for 24 h revealed a novel 76,000-dalton protein (CKp76). The kinetics of its appearance paralleled the inhibition of fluid-phase pinocytosis. CKp76 was not detected in cultures pretreated with actinomycin D, or prelabeled with [35S]methionine, prior to IFN addition. However, the presence of cycloheximide during incubation with IFN had no effect on the synthesis of CKp76 after removal of both agents. These results suggest that the appearance of CKp76 was due to enhanced transcription of its gene in response to IFN. Subcellular fractionation revealed the presence of induced CKp76 in the nuclear pellet. From these results it is possible that CKp76 may be responsible at leat in part for the effects of IFN on fluid-phase pinocytosis.

Interferon inhibits the establishment of competence in Go/S-phase transition

Addition of mouse interferon-alpha/beta (IFN) to confluent, quiescent BALB/c 3T3 (clone A31) mouse fibroblasts resulted in a block or delay in serum-induced activation of the cell cycle. It was necessary to add IFN within 6 hours after serum stimulation to inhibit nuclear labeling with [3H]thymidine. This is consistent with the time required for platelet-derived growth factor (PDGF) to induce cells to become competent to respond to additional growth factors present in platelet-poor plasma. Simultaneous addition of IFN with PDGF inhibited the PDGF-induced synthesis of a 29-kilodalton and a 35-kilodalton protein that normally occurs within 1 hour after PDGF addition. IFN also suppressed the general increase in protein synthesis that occurs by the fifth hour after PDGF addition. These results show that IFN antagonizes the action of PDGF, thereby interfering with the activation of Go cells for G1 traverse and S-phase entry.

Nadolol and supraventricular tachycardia: an electrophysiologic study

To assess antiarrhythmic efficacy of oral nadolol, 15 patients with recurrent supraventricular tachycardia were studied. Eight patients had atrioventricular (AV) nodal reentrant tachycardia and seven had AV reciprocating tachycardia involving an accessory AV pathway. Electrophysiologic studies were performed before and after intravenous infusion of propranolol (0.20 mg/kg), and were repeated 5 to 8 days after oral nadolol therapy at a daily dose of 80 to 160 mg. Both intravenous propranolol and oral nadolol induced significant prolongation of the sinus cycle length from 741 +/- 73 ms to 834 +/- 97 and 1,029 +/- 95 ms, respectively (p less than 0.001 and p less than 0.0001, respectively). Both intravenous propranolol and oral nadolol depressed AV nodal but not accessory AV pathway conduction, and shifted the dual AV nodal pathway conduction curves (A1A2, A2H2; A1A2, H1H2) upward and to the right by prolonging the conduction time and increasing the refractory period. Ten patients (seven with AV nodal reentry and three with AV reciprocation) who responded to intravenous propranolol also responded to oral nadolol with loss of the inducibility of sustained tachycardia; the remaining five patients (one with AV nodal reentry and four with AV reciprocation) who did not respond to intravenous propranolol also failed to respond to oral nadolol with persistence of the inducibility of sustained tachycardia. Thus, in conclusion, intravenous propranolol testing predicts the therapeutic efficacy of oral nadolol therapy and oral nadolol in once-daily doses may be used for long-term prophylaxis of recurrent supraventricular tachycardia.

Reduced synthesis of pp60src and expression of the transformation-related phenotype in interferon-treated Rous sarcoma virus-transformed rat cells

Treatment of Rous sarcoma virus-transformed rat cells with rat interferon-alpha (specific activity, 10(6) U/mg of protein) for 24 h caused a 50% reduction in intracellular pp60src-associated protein kinase activity. Staphylococcus aureus V8 protease digestion of pp60src, derived from 32P-labeled monolayer cultures incubated with or without interferon, revealed no differences either in the phosphopeptide pattern or in the phosphoserine-phosphotyrosine ratio. However, [3H]leucine pulse-labeling experiments showed that the synthesis of pp60src was reduced by 42 to 48%, relative to the level of bulk protein synthesis, in the interferon-treated cultures. Rat interferon-alpha also reduced the growth rate of Rous sarcoma virus-transformed rat cells in a dose-dependent manner over a 72-h period. The decrease in growth rate was accompanied by increases in the thickness and number of actin fibers per cell and by a decline in intracellular tyrosine phosphorylation by pp60src. The results suggest that interferon can inhibit the expression of the transformation-related phenotype by selectively reducing the synthesis of the Rous sarcoma virus transforming gene product. However, the interferon effects on the cytoskeletal organization and proliferation of Rous sarcoma virus-transformed cells may be due at least in part to the predominance of interferon-induced phenotypic changes over those caused by pp60src.

Epidermal growth factor-urogastrone action: induction of 2',5'-oligoadenylate synthetase activity and enhancement of the mitogenic effect by anti-interferon antibody

Epidermal growth factor-urogastrone (EGF-URO), early in the course of stimulating DNA synthesis in quiescent human fibroblasts, also causes a three to five-fold elevation of the activity of intracellular 2',5'-oligoadenylate synthetase (2,5A synthetase), an enzyme that has been previously implicated in the antiproliferative effects of interferon. The increase in synthetase activity precedes DNA synthesis by approximately six hours, with maximal synthetase activity either preceding or coinciding with maximal DNA synthesis. EGF-URO stimulation does not result in the secretion of detectable amounts of interferon (IFN) into the growth medium and anti-human IFN-beta antibodies do not block the EGF-URO-mediated rise in 2,5A synthetase activity. Thus, the elevation of 2,5A synthetase can be attributed to the action of EGF-URO itself, and not to IFN. Nonetheless, in the presence of anti-human interferon-antibodies, the time course of EGF-URO-stimulated DNA synthesis is prolonged both in human and in Syrian hamster embryo fibroblasts; the effects of the antibody were reversed in both cell strains by the addition of human IFN-beta (HuIFN-beta). The data suggest a role for 2',5'-oligoadenylate synthetase in the process of EGF-URO-mediated mitogenesis and point to the possible production of interferon-related cell-associated regulators during the course of EGF-URO action.

A new collimator for cardiac tomography: the quadrant slant-hole collimator

A quadrant slant-hole (QSH) collimator was constructed for myocardial perfusion tomography on a 15-inch large-field gamma camera. This system optimizes the crystal area for multiple-view photon detection while at the same time offering excellent tomographic performance. In addition to the advantages associated with parallel slant-hole collimation, this system's four orthogonal views provide a solution to the problem of patient positioning, namely, proper alignment of the long axis of the left ventricle to the camera. Rapid data acquisition, together with fast reconstruction, make the QSH system a practical approach to tomographic imaging of the myocardium.

The Effects of Anisotropic Scattering on Electron Transport

The recently developed theory of Lin et al. has been used to make a systematic study of calculated electron drift velocities and diffusion coefficients. Differences between the usual two-term solution and the converged results are calculated for a number of cases to demonstrate the effects of anisotropic scattering on the interpretation of swarm experiments.

Equivalence of microbiological and hydroxylamine methods of analysis for ampicillin dosage forms

Ampicillin formulations were assayed by microbiological and hydroxylamine methods to determine whether thehydroxylamine analytical method is a suitable substitute for the microbiological method. Paired assay results by the 2 analytical methods were obtained on different strengths of tablet, capsule, and suspension, formulations containing ampicillin and ampicillin degradation compounds. Several statistical tests were used to assess the equivalence of the paired assay results. The data analyses indicate that the hydroxylamine method is a suitable substitute for the microbiological method for potency assays and stability studies of ampicillin formulations. The hydroxylamine method yielded slightly higher assay results than the microbiological method for severely degraded formulations.