Mid-infrared-near-infrared double-resonance spectroscopy of molecules with kilohertz accuracy

Precision measurements of molecular transitions to highly excited states are needed in potential energy surface modeling, state-resolved chemical dynamics studies, and astrophysical spectra analysis. Selective pumping and probing of molecules are often challenging due to the high state density and weak transition moments. We present a mid-infrared and near-infrared double-resonance spectroscopy method for precision measurements. As a demonstration, Doppler-free stepwise two-photon absorption spectra of 13CO2 were recorded by pumping the fundamental transition of R14 (00011)-(00001) and probing the P15 (00041)-(00011) transition enhanced by a high-finesse optical cavity, and the transition frequencies were determined with an accuracy of a few kilohertz.

Precision spectroscopy of molecular hydrogen

Precision measurements on the hydrogen molecule are of fundamental importance in understanding molecular theory. Comparison of accurate experimental data and theoretical results are used to test the quantum electrodynamics theory and determine physical constants used in the calculation. We review recent advances and perspectives in the precision spectroscopy of molecular hydrogen, representing state-of-the-art molecular spectroscopy methods and cutting-edge high-precision calculations.

Optical-Optical Double-Resonance Absorption Spectroscopy of Molecules with Kilohertz Accuracy

Selective pumping and probing of highly excited states of molecules are essential in various studies but are also challenging because of high density of states, weak transition moments, and lack of precise spectroscopy data. We develop a comb-locked cavity-assisted double-resonance spectroscopy (COCA-DR) method for precision measurements using low-power continuous-wave lasers. A high-finesse cavity locked with an optical frequency comb is used to enhance both the pumping power and the probing sensitivity. As a demonstration, Doppler-free stepwise two-photon absorption spectra of CO₂ were recorded by using two milliwatt diode lasers (1.60 and 1.67 μm), and the rotation energies in a highly excited state (CO-stretching quanta = 8) were determined with an unprecedented accuracy of a few kilohertz.

Prednisolone dose during treatment of tuberculosis might be a risk factor for mortality in patients with systemic lupus erythematosus: a hospital-based cohort study

Patients with systemic lupus erythematosus (SLE) are at high risk of tuberculosis (TB) because of their immunocompromised status and the use of immunosuppressive drugs. In endemic regions, TB complicates the diagnosis and treatment of SLE, but the risk factors of mortality in these patients have not been investigated. In this study, we reviewed medical records during 2006–2016. Patients who fulfilled the 1997 American College of Rheumatology SLE criteria and presented with definite TB were enrolled. The primary outcome was mortality during TB treatment. There were 5388 SLE patients screened, and 30 patients were enrolled. Seven patients died during follow-up. Compared with the survival group, patients in the mortality group had significantly more central nervous system involvement of TB, higher Systemic Lupus Erythematosus Disease Activity Index-2000 scores and more cyclophosphamide use before TB, and higher prednisolone dose before and during TB treatment. Cox regression showed that prednisolone dose during TB treatment was an independent risk factor for mortality (per 10 mg/day increase, hazard ratio (HR) 1.61, p = .019). For SLE patients, prednisolone dose during TB treatment is an independent risk factor for mortality. Keeping prednisolone dose at less than 25 mg per day during TB treatment might be a reasonable strategy in these patients.

Multichannel continuous-wave fiber cavity ringdown gas sensing utilizing frequency-shifted interferometry

We present a multichannel continuous-wave (CW) fiber cavity ringdown (FCRD) gas sensing method based on frequency-shifted interferometry (FSI). This scheme detects gas concentration by measuring the intensity decay rates of continuous light from different ringdown cavities in the spatial domain, unlike conventional FCRD techniques, which measure the decay rates of pulse light in the time domain. This method shares one CW light source, one slow detector, and one slow data collector. In order to illustrate the theory, acetylene gas concentration measurement in a two-channel FSI-FCRD system was experimentally conducted in the range of 0%-1%. A linear relation was established between concentration and absorption loss, which is proportional to the intensity decay rate, and the measurement resolutions of 3.871%/dB and 3.658%/dB were achieved, respectively. The results reveal that the proposed system has the advantages of low cost, high sensitivity, high precision, and good stability in multichannel gas detection.

Normalization of the single atom counting rate in an atom trap

The single atom counting rate of a rare isotope and the loading rate of another stable isotope with an abundance over 10 orders of magnitude larger are measured in one atom trap. The linear correlation between the measured counting/loading rates is examined to determine the (84)Kr/(82)Kr and (85)Kr/(83)Kr ratios of a Kr gas sample. Experiments show that the relative uncertainty is reduced to 1.3% when the single atom counting rate of (85)Kr is normalized by the measured (83)Kr loading rate. The measurement of the normalized single atom counting rate can be used to determine extremely low (10(-16)-10(-11)) isotope abundance. This normalization method is robust and can also be applied in other atomic systems.

Effects of the different frequencies of whole-body vibration during the recovery phase after exhaustive exercise

AIM

This study was to investigate the effects of vibration exercise on the oxygen consumption (VO2) and heart rate variability (HRV) during the recovery phase after exhaustive exercise.

METHODS

Twenty male college students volunteered as subjects to participate in the study. The subjects were randomly crossover assigned to perform three 10 min vibration exercises, namely non-vibration (CON, 0 Hz, 0 mm), low-frequency (LFT, 20 Hz, 0.4 mm) and high-frequency (HFT, 36 Hz, 0.4 mm) treatments immediately after an incremental exhaustive cycling exercise in separated days. The beat-to-beat HRV, blood lactate concentration and VO2 were measured during the 1-hour recovery phase. The time- and frequency-domain indices of HRV were analyzed to confirm the effects of vibration exercises on the cardiac autonomic modulation.

RESULTS

There were no significant differences on the VO2, HRV and blood lactate concentrations at 30th minute (post-30 min) or 60th minute (post-60 min) during the recovery phase among the three treatments. There were also no significant differences on the excess post-exercise oxygen consumption (EPOC) during the recovery phase among the treatments. However, the VO2 at post-30 min in CON and LFT were significantly higher than the baseline values, whereas the VO2 in HFT returned to resting condition at the post-30 min.

CONCLUSIONS

The results indicate that both low and high frequency vibration exercises could not improve the physiological recovery after exhaustive cycling exercise. However, the high frequency vibration exercise probably has a potential to facilitate the VO2 to return to the resting level during the recovery phase.

Ultrasensitive near-infrared cavity ring-down spectrometer for precise line profile measurement

A cavity ring-down (CRD) spectrometer is built with a continuous-wave Ti:sapphire ring laser. Using a pair of R approximately 0.999 95 high-reflective mirrors, the noise-equivalent minimum detectable absorption loss reaches 7 x 10(-11)/cm over the spectral range of 780-830 nm. A thermal-stabilized Fabry-Perot interferometer is applied to calibrate the CRD spectrum with an accuracy of 1 x 10(-4) cm(-1). The quantitative measurement is carried out for the line profile measurements of some overtone absorption lines of C(2)H(2) near 787 nm. Doppler determined line shape has been observed with milli-Torr acetylene gas in the ring-down cavity. The instrumental line width is estimated from the line profile fitting to be <1 x 10(-4) cm(-1). It demonstrates that the CRD spectrometer with extremely high sensitivity is also very suitable for quantitative measurements including precise line profile studies in the near-infrared.

A frequency-stabilized difference frequency generation laser spectrometer for precise line profile studies in the midinfrared

A midinfrared laser spectrometer is built up based on the difference frequency generation (DFG) of a Nd:YAG (yttrium aluminum garnet) laser and a tunable Ti:sapphire (Ti:Sa) laser. Tuning the Ti:Sa laser and operating properly with the periodically poled lithium niobate crystal, the DFG emission is tunable in the spectral range of 2.3-5.0 microm. The 1064 nm Nd:YAG laser frequency is stabilized to the 10(-6) cm(-1) level on a Doppler-broadened I(2) absorption line at 532 nm. As a result, the DFG emission frequency is stabilized within 1x10(-4) cm(-1). The measurement of an absorption line of CH(4) near 3 mum demonstrates that the DFG spectrometer is very suitable for the molecular absorption line profile studies in the midinfrared region.

Screening and mutagenesis of a novel Bacillus pumilus strain producing alkaline protease for dehairing

AIMS

To characterize and optimize a novel Bacillus pumilus strain isolated from biological waste which produces protease with excellent dehairing effect. This newly isolated strain could be utilized in the industrial leather dehairing process.

METHODS AND RESULTS

Bacterial strains secreting proteases were screened from biological wastes. Positive clones were further characterized by analysing their efficacy in dehairing and effects on collagen integrity. Among 171 colonies tested, a strain BA06, identified as B. pumilus, was picked owing to its efficient dehairing capabilities with minimal impact on collagen. By combined mutagenesis using UV, N-methyl-N'-nitro-N-nitrosdguanidine and Co(60)-gamma-rays, this strain was further improved with regard to its alkaline protease production. The alkaline protease activity of the mutant strain SCU11was greatly improved up to 6000 U ml(-1), in comparison with its parent strain BA06 of 1200 U ml(-1).

CONCLUSIONS

By using screening and mutagenesis methods, we have successfully created a B. pumilus strain that can produce high levels of alkaline proteases that are able to efficiently remove hair from skin with minimal damage on the collagen.

SIGNIFICANCE AND IMPACT OF THE STUDY

This strain could be used in commercial alkaline protease production for leather dehairing.

Optical breakdown for silica and silicon with double femtosecond laser pulses

The optical breakdown thresholds (OBTs) of typical dielectric and semiconductor materials are measured using double 40-fs laser pulses. By measuring the OBTs with different laser energy and different time delays between the two pulses, we found that the total energy of breakdown decrease for silica and increase for silicon with the increase of the first pulse energy.

A defect in the Kv channel-interacting protein 2 (KChIP2) gene leads to a complete loss of I(to) and confers susceptibility to ventricular tachycardia

KChIP2, a gene encoding three auxiliary subunits of Kv4.2 and Kv4.3, is preferentially expressed in the adult heart, and its expression is downregulated in cardiac hypertrophy. Mice deficient for KChIP2 exhibit normal cardiac structure and function but display a prolonged elevation in the ST segment on the electrocardiogram. The KChIP2(-/-) mice are highly susceptible to the induction of cardiac arrhythmias. Single-cell analysis revealed a substrate for arrhythmogenesis, including a complete absence of transient outward potassium current, I(to), and a marked increase in action potential duration. These studies demonstrate that a defect in KChIP2 is sufficient to confer a marked genetic susceptibility to arrhythmias, establishing a novel genetic pathway for ventricular tachycardia via a loss of the transmural gradient of I(to).

Ablation of Cypher, a PDZ-LIM domain Z-line protein, causes a severe form of congenital myopathy

Cypher is a member of a recently emerging family of proteins containing a PDZ domain at their NH(2) terminus and one or three LIM domains at their COOH terminus. Cypher knockout mice display a severe form of congenital myopathy and die postnatally from functional failure in multiple striated muscles. Examination of striated muscle from the mutants revealed that Cypher is not required for sarcomerogenesis or Z-line assembly, but rather is required for maintenance of the Z-line during muscle function. In vitro studies demonstrated that individual domains within Cypher localize independently to the Z-line via interactions with alpha-actinin or other Z-line components. These results suggest that Cypher functions as a linker-strut to maintain cytoskeletal structure during contraction.

Morphological characterization of ventricular septal defect with posterior deviation of the outlet septum

Ventricular septal defect (VSD) with posterior deviation of the outlet septum is frequently associated with left ventricular outflow obstruction and aortic arch anomalies. In this study, 17 patients with large VSD and posterior deviation of the outlet septum were evaluated. The VSD was further classified into 'high' and 'low' types according to the extension of the VSD; the high-type VSD (8 patients) extended mainly to the outlet or infundibular portion and the low-type VSD (9 patients) extended mainly to the trabecular or inlet portion. Related morphological features, such as outlet septum hypoplasia, muscle bundle between aortic-mitral valve junction, pulmonary artery overriding and aortic arch anomalies, were found more frequently in patients with high-type VSD, while tricuspid valve straddling and outlet septum hypertrophy were found more often in patients with low-type VSD. This classification for VSD with posterior deviation of the outlet septum helps to predict the morphological features of left ventricular outflow tract and aortic arch anomalies.

Effects of cancer therapy on dental and maxillofacial development in children: report of case

Malignant lymphoma is one of the most common hematological diseases of children. The prognosis is fairly good with multimodal cancer therapy. We reported a boy with Burkitt's lymphoma in the nasal cavity who received chemotherapy and irradiation of the head and neck area at four years of age. During seven years of follow-up, we studied the developmental effects of cancer therapy, including general growth, maxillofacial bones, and dentition. Compared with boys of matching age, the development of his entire body and maxillofacial bones was delayed. In the irradiated areas, the roots of teeth were short or poorly developed and the root apices showed premature closure. After the patient was in remission from the tumor in his early childhood, the long-term effects of cancer therapy on dental and maxillofacial development are worth our further evaluation and follow-up.

Pulmonary vein atresia with Shone's anomaly in an infant: a case report

We report a case of individual pulmonary vein atresia associated with multiple levels of left heart obstruction, including aortic coarctation, valvular aortic stenosis, and parachute mitral valves with stenosis. The diagnosis of pulmonary vein obstruction is likely to be missed in patients who also have other left heart obstructive diseases, since the latter usually dominates the clinical presentation. We diagnosed the existence of individual pulmonary vein atresia preoperatively via cardiac catheterization. The pulmonary artery angiograms revealed back and forth motion of the dye with no visualization of either a capillary or venous phase on the lesion side. The pulmonary capillary wedge pressure was unevenly elevated and highest on the lesion side. The results were later confirmed by operation and autopsy. Thus, selective pulmonary artery catheterization and angiography remains a good diagnostic tool to rule out the existence of pulmonary vein obstruction in cases which have multiple levels of left heart obstruction.

Separation of N-nitrosoamino acids by C18 reversed-phase ion-pair high-performance liquid chromatography and compatible detection by electrospray ionization mass spectrometry

Four non-volatile N-nitrosoamino acids, namely N-nitrososarcosine, N-nitrosoproline, N-nitrosothiazolidine-4-carboxylic acid and N-nitroso-2-methyl-thiazolidine-4-carboxylic acid were separated by C18 reversed-phase ion-pair high-performance liquid chromatography (HPLC) using 1.4 mM C16-cetyltrimethylammonium chloride in methanol-water-acetonitrile (60:35:5, v/v) as the mobile phase. The N-nitrosoamino acids were sensitively detected by negative electrospray ionization mass spectrometry (ESI-MS) in the form of the deprotonated carboxylate anion, [M-H]-. Compatibility problems associated with HPLC separation and ESI-MS detection, such as formation of solvent cluster ions and the effects of co-eluting anions of the ion-pairing reagent, were systematically investigated. The optimized experimental conditions for separation and detection of N-nitrosoamino acids were described.

Pharmacokinetic and depletion studies of sarafloxacin after oral administration to eel (Anguilla anguilla)

The pharmacokinetics of sarafloxacin applied by oral gavage at a dose of 15 mg/kg b.w. was studied in eel (Anguilla anguilla) at water temperature of 24 degrees C. Sarafloxacin levels were determined using high performance liquid chromatography with a quantitation limit of 0.07 microg/ml or gram. The time to peak plasma concentration, Tmax, was 12 hr and peak concentration, Cmax, was 2.64 microg/ml. The absorption rate constant (k(a)) was 0.23 hr(-1) (r=0.996). The drug disposition curve after Tmax was fitted to a two-compartment open model. The distribution rate constant (alpha) was 0.085 hr(-1) (r=0.972), and the half-life (t(1,2alpha)) was 8.15 hr. The elimination rate constant (beta) was 0.023 hr(-1) (r=0.909), and the half-life (t(1/2beta)) was 30.13 hr. The estimated area under the curve, AUC, was 56.7 microg.hr/ml. The peak concentrations of drug in liver, kidney, muscle, and skin were 13.39 (12 hr), 5.53 (12 hr), 1.82 (24 hr), and 0.78 microg/g (40 hr), respectively. The time for sarafloxacin mean levels to fall below detectable limits in the plasma, muscle, and skin were 7 days but for the liver and kidney were 14 days.

Balloon dilatation for critical pulmonary stenosis

This study was conducted to investigate the outcome of balloon valvuloplasty for critical pulmonary stenosis in young infants. During a 6.2-year period between January 1992 and February 1998, 34 infants with critical pulmonary stenosis, aged 1 to 58 days (16.8+/-16.6 days), underwent attempted balloon valvuloplasty in this institution. The procedure was accomplished in 28 patients, but failed in six. Surgical pulmonary valvotomy was performed in the six patients with one mortality. Immediately following valvuloplasty, the mean right ventricular systolic pressure decreased from 109.2+/-28.6 to 55.1+/-23.6 mm Hg in the 28 patients (P<0.01). The mean pressure gradient decreased from 85.6+/-29.4 to 26+/-21.4 mm Hg (P<0.01). However, one who had a severely hypoplastic right ventricle requiring prolonged prostaglandin E1 infusion after valvuloplasty underwent a right ventricular outflow tract patch. After a follow-up period ranging from 2 months to 6.4 years (30.5+/-19.1 months), one patient developed recurrent pulmonary stenosis and underwent a repeated balloon valvuloplasty. Of the 27 patients (79%) with a definitive success of balloon valvuloplasty, the mean pressure gradient estimated with Doppler echocardiography at most recent follow-up was 15.2+/-6.8 mm Hg. Therefore, balloon valvuloplasty is the procedure-of-choice for critical pulmonary stenosis. Surgery should be reserved for those with unsuccessful balloon valvuloplasty.

Differential pulmonary flow in hypoplastic left heart syndrome

We report a case of hypoplastic left heart syndrome associated with restrictive interatrial communication and partial anomalous pulmonary venous connection via a right lower pulmonary vein draining to the inferior vena cava. We found unequal pulmonary artery pressure and different pulmonary artery structure, with the right pulmonary artery being lower in pressure and more tortuous and dilated in its peripheral branches than the left. This was attributed to the variant degrees of pulmonary venous obstruction. The left pulmonary venous return was severely obstructed by the restrictive interatrial communication, whereas the anomalous right lower pulmonary vein drained into the inferior vena cava, with less obstruction. To the best of our knowledge, there has never before been a report of differential pulmonary flow associated with a partial anomalous pulmonary vein, in a case of hypoplastic left heart syndrome.

Simultaneous determination of nitrite, nitrate and ascorbic acid in canned vegetable juices by reverse-phase ion-interaction HPLC

A simple ion-interaction C18 reverse-phase high performance liquid chromatographic method was developed for simultaneous determination of nitrite, nitrate and ascorbic acid in canned vegetable juices. The method makes use of 0.010 M octylammonium orthophosphate as the ion interacting reagent and 20% (v/v) aqueous methanol as the mobile phase. The content of nitrite, nitrate (expressed as nitrite ion and nitrate ion, respectively) and ascorbic acid in commercial brands of canned tomato, carrot and mixed vegetable juices were surveyed. The quantitative results indicated that nitrite was very probably added as a preservative in the canned vegetable juices. The total amount of nitrite and nitrate ion per can in two commercial brands of vegetable juices was found to exceed the acceptable daily intake recommended by the 1996 Joint FAO/WHO Expert Committee on Food Additives for an average adult of 60 kg body weight.

Angiographic evidence of long-axis rotation in addition to short-axis aortopulmonary rotation: its implication in transposition of the great arteries

To assess the pattern of aortic sinus in varied aortopulmonary rotations and its clinical implications, three aortic sinuses at the diastolic phase in true lateral view are identified in 53 angiograms of complete transposition of the great arteries recorded between 1988 and 1993. The patients with the high takeoff of the coronary arteries found at surgery and in the literature were selected for additional investigation. Six regions were defined on the horizontal plane. From left anterior 89 degrees to 61 degrees, the non-facing sinus moved toward the anterior aspect (one patient). From left anterior 60 degrees to left anterior 1 degree, the left-hand sinus moved gradually from an anterior toward a posterior location (two patients). From directly anterior 0 degree to right anterior 59 degrees, the right-hand sinus moved from posterior toward an anterior position (30 patients). From right anterior 60 degrees to right posterior 105 degrees, the non-facing sinus moved posteriorly (20 patients). On approaching directly anterior 0 degree and toward right anterior 60 degrees, the left-hand sinus was the lowest in anterior transposition of the great arteries instead of the non-facing sinus, as in left anterior 90 degrees and in posterior transposition of the great arteries. High takeoff occurred commonly above the lowest left-hand sinus in anterior transposition of the great arteries (2 cases here and 5 in the literature, 100%). In conclusion, aortopulmonary rotations about the short and long axes were both evident on identification of the aortic sinus in various rotations. The aortic sinus did not rotate along the long-axis in anterior transposition of the great arteries, thus making the left-hand sinus, the lowest of this group, vulnerable to the high takeoff of the coronary arteries in anterior transposition of the great arteries.

Evolution of coronary artery pattern according to short-axis aortopulmonary rotation: a new categorization for complete transposition of the great arteries

OBJECTIVES

We studied the correlation between coronary artery pattern and aortopulmonary rotation in complete transposition of the great arteries.

BACKGROUND

Classifications of the coronary arteries in complete transposition are puzzling and incomplete.

METHODS

Coronary artery anatomy and relation of the great arteries were identified at angiography, echocardiography, surgical intervention or autopsy in 76 patients with complete transposition from 1988 to 1993. Five main types (type 0 and Shaher types 1,2,4 and 9) and their similar variants of epicardial configuration were categorized into five patterns (O, I, II, IV and IX). In addition, data from 568 cases from published reports were collected for analysis.

RESULTS

As the aorta rotated from a left anterior to a directly anterior location relative to the pulmonary trunk, the left anterior descending coronary artery arose from the left-hand sinus together with the right coronary artery (type 0, one case decreased to no cases); then it gradually shifted to the left to have the same origin as the left circumflex coronary artery from the right-hand sinus (type 1, 10 cases increased to 146, p < 0.0003). When the aorta rotated farther clockwise from directly anterior to right anterior (type 1, 146 cases increased to 235; type 2, 9 cases increased to 50, p < 0.0006) or from right anterior to right lateral (type 1, 235 cases decreased to 6 cases; type 2, 50 cases decreased to 20, p < 0.00000), the left circumflex coronary artery tended to move retropulmonically and originated from the left-hand sinus with the right coronary artery (type 2). When the aorta moved from right anterior to right lateral (type 2, 50 cases decreased to 20; type 4, 13 cases increased to 14, p < 0.031) or from right lateral to right posterior (type 2, 20 cases decreased to 1; type 4, 14 cases increased to 16, p < 0.0003), the right coronary artery shifted to the right-hand sinus anteaortically to join the left anterior descending coronary artery (type 4). Finally, the left anterior descending coronary artery combined with the left circumflex coronary artery (type 9, 12 cases increased to 21, p = 0.407) to become the usual pattern for normally related great arteries. Eta-square analysis showed that the evolution from pattern O to IX was dependent on clockwise aortopulmonary rotation.

CONCLUSIONS

The coronary arteries in complete transposition of the great arteries can be classified into five patterns and their evolution deduced on the basis of aortopulmonary rotation. Dependence of coronary artery type on aortopulmonary rotation made it possible to anticipate the coronary pattern from the relation of the great arteries in transposition.

Ductus-dependent aortic coarctation with a left-to-right shunt through the ductus: report of one case

A 20 days old female baby presenting with dyspnea was found to have coarctation of the aorta and patent ductus arteriosus by echocardiography. The Doppler spectral display disclosed mainly a left-to-right shunt through the ductus. Therefore, the prostaglandin El infusion was discontinued. She developed acute left heart failure, and the echocardiograms at that time showed a markedly narrowed juxtaductal aortic coarctation with a closed ductus. After resumption of prostaglandin El, with an attenuated juxtaductal aortic coarctation, the left ventricular contractility and the systemic perfusion improved. Therefore, we conclude that the central role of a patent ductus in such a patient is to avoid the ductal constriction which will worsen the aortic coarctation.

Blocking of lung endothelial cell adhesion molecule-1 (Lu-ECAM-1) inhibits murine melanoma lung metastasis

The 90-kD lung endothelial cell adhesion molecule-1 (Lu-ECAM-1) selectively promotes Ca(2+)-dependent adhesion of lung-metastatic B16 melanoma cells. Corresponding with their metastatic performance, high lung-metastatic B16-F10 melanoma cells bind in significantly higher numbers to Lu-ECAM-1 than their intermediate and low lung-metastatic counterparts B16-L8-F10 and B16-F0, respectively. Maximum attachment is observed at a density of approximately 2.4 x 10(2) Lu-ECAM-1 sites/microns2 of plastic surface. B16 melanoma cell binding to Lu-ECAM-1 is blocked by mAb 6D3 and is competitively inhibited by soluble Lu-ECAM-1. C57B1/6 mice passively immunized with anti-Lu-ECAM-1 mAb 6D3 or actively immunized with purified Lu-ECAM-1 exhibit an anti-Lu-ECAM-1 antibody titer-dependent reduction in the number of B16 experimental metastases. Lu-ECAM-1 promotes neither binding nor metastasis of other lung-metastatic tumor cells (e.g., KLN205). Our data indicate that an "antiadhesion" therapy directed at interfering with the adherence of blood-borne tumor cells to organ-specific vascular endothelium is efficient in the control of metastasis formation in selective organ sites.

Mediation of lung metastasis of murine melanomas by a lung-specific endothelial cell adhesion molecule

Organ-specific adhesion molecules expressed by vascular endothelial cells have been implicated in the arrest of blood-borne cancer cells in selective, secondary sites. A lung-specific endothelial cell adhesion molecule (Lu-ECAM-1) localized on endothelia of distinct branches of lung blood vessels has been purified by immunoaffinity chromatography from detergent extracts of lung matrix-modulated endothelial cells using monoclonal antibody (mAb) 6D3. It has a molecular mass of 90 kDa and promotes the selective attachment of lung-metastatic B16 melanoma cells. Corresponding with their metastatic performance, B16-F10 tumor cells selected for higher lung colonization bind to Lu-ECAM-1 in significantly higher numbers than their low lung metastatic counterpart B16-F0. Binding of B16-F0 and B16-F10 is reduced with mAb 6D3 to slightly lower levels than B16-F0 bound to Lu-ECAM-1. mAb 6D3 injected into C57BL/6 mice 1 hr prior to an i.v. challenge with B16-F10 causes a 90% reduction in the number of lung colonies compared with animals injected with control mAb (6D8 or 3C6). Lu-ECAM-1 neither binds nor effects metastasis of other lung-colonizing tumor cells (e.g., KLN205). Thus, site-specific metastasis of tumor cells is regulated by similar mechanisms as the homing of lymphocytes--namely, by the ability of blood-borne cancer cells to recognize and adhere to distinct endothelial cell adhesion molecules.

Purification and characterization of human lipoprotein lipase and hepatic triglyceride lipase. Reactivity with monoclonal antibodies to hepatic triglyceride lipase

Human lipoprotein lipase and hepatic triglyceride lipase were purified to homogeneity from post-heparin plasma. These enzymes were purified 250,000- and 100,000-fold with yields of 27 +/- 15 and 19 +/- 6%, respectively. Molecular weight determination by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and reducing agents yielded Mr of 60,500 +/- 1,800 and 65,200 +/- 400, respectively, for lipoprotein lipase and hepatic triglyceride lipase. These lipase preparations were shown to be free of detectable antithrombin by measuring its activity and by probing of Western blots of lipases with a monospecific antibody against antithrombin. In additions, probing of Western blots with concanavalin A revealed no glycoproteins corresponding to the molecular weight of antithrombin. Four stable hybridoma-producing distinct monoclonal antibodies (mAb) to hepatic triglyceride lipase were isolated. The specificity of one mAb, HL3-5, was established by its ability to immunoprecipitate hepatic triglyceride lipase catalytic activity. Interaction of HL3-5 with this lipase did not inhibit catalytic activity. The three other mAb interacted with hepatic triglyceride lipase only after denaturation of the enzyme with detergents. The relatedness of these two enzymes was examined by comparing under the same conditions the thermal inactivation, the sensitivity to sulfhydryl and reducing agents, amino acid composition, and the mobility of peptide fragments generated by cyanogen bromide cleavage. The results of these studies strongly support the view that the two enzymes are different proteins. Immunological studies confirm this conclusion. Four mAb to hepatic triglyceride lipase did not interact with lipoprotein lipase in Western blots, enzyme-linked immunosorbent assay, and immunoprecipitation experiments. These immunological studies demonstrate that several epitopes of the hepatic triglyceride lipase protein moiety are not present in the lipoprotein lipase molecule.

Binding of lipoprotein lipase to endothelial cells in culture

Equilibrium-binding data of highly purified avian lipoprotein lipase to cultured bovine endothelial cells demonstrate the presence of a class of high affinity sites. Analysis of the binding function by weighted least squares technique yielded an association constant of K = 0.7 X 10(7) M-1 and a maximum binding capacity of 1.6 micrograms/1.9 X 10(6) cells. Lipoprotein lipase was monitored both by its catalytic activity and a sensitive radioimmunoassay which permitted the accurate measurement of nanogram quantities of enzyme protein. Specific activity of the bound enzyme was similar to that of the initial purified enzyme. Lipoprotein lipase binding to endothelial cells was inhibited 80% by preincubating cells in 0.1% trypsin for 3 min at 37 degrees C, 92% by 0.01% pronase, and 91% by 0.008% proteinase K. Heparin was most efficient in releasing lipoprotein lipase from endothelial cells. Fifty per cent of the enzyme appeared in the medium at a concentration of 3 micrograms/ml of heparin. At the same concentration of heparan sulfate, 20% of the enzyme was released. Hyaluronic acid and chondroitin sulfate were not effective in stimulating enzyme release. Preincubating endothelial cells with purified human platelet endoglucuronidase for 1 h at 37 degrees C led to a 90% reduction in lipoprotein lipase binding. Endoglucuronidase was purified 20,000-fold as compared to the initial platelet lysate by a 5-step purification method. The extent of inhibition of binding was shown to be dependent on concentration of endoglucuronidase in the preincubation medium. The specificity of platelet endoglucuronidase and the demonstration that the preparation utilized contained no detectable protease activity is further evidence that lipoprotein lipase is bound to endothelial cell heparan sulfate or heparan sulfate-like molecules.

Direct and reflex effects of nitroglycerin on the blood volume distribution, evaluated by regional weighing in the cat

The effects of nitroglycerin on the blood volume distribution were studied with a method of regional weighing in the anaesthetized cat. An i.v. bolus injection of nitroglycerin produced a dose-dependent decrease in arterial pressure accompanying a decrease in the thoracic blood volume. The latter change was associated with blood volume increases principally in the abdomen, and slightly in the hindquarters. Elimination of the cardiovascular reflex effects by carotid sinus denervation and cervical vagotomy signficantly enhanced and prolonged the following changes: the hypotension, the decrease in thoracic blood volume and the volume pooling in the abdomen. The magnitude of increase in hindquarters blood volume was not significantly affected by the denervation procedures, but the duration was much prolonged. The results indicate that the major site of nitroglycerin-induced venous pooling is in the splanchnic circulation. The peripheral venous pooling is produced at the expense of a decrease in the central or pulmonary blood volume. The secondary reflex adjustments tend to minimize the direct effects of nitroglycerin on the blood pressure and blood volume distribution.

Purification and characterization of rat heart and brain catechol methyltransferase

In an effort to detect the similarities and differences in the properties of rat heart, brain and liver catechol methyltransferase (S-adenosyl-L-methionine:catechol O-methyltransferase, EC 2.1.1.6), we have determined the cellular distribution of this enzyme activity and extensively purified the soluble and microsomal enzymes present in these tissues. Purification of soluble heart (688-fold) and brain enzymes (240-fold) were achieved using an affinity chromatographic system. The properties of these enzymes were compared with respect to their molecular weights, substrate specificities, inhibitor specificities and immunological properties. The characteristics of the enzyme active sites were investigated using various methyl acceptor substrates and various analogs of S-adenosylmethionine as methyl donors. A series of analogs of S-adenosylhomocysteine was also evaluated as inhibitors of these enzymes. The immunological properties of the purified soluble and microsomal enzymes from heart and brain were investigated using an antibody isolated from rabbits which had been immunized with the soluble rat liver enzyme. In general the properties of catechol methyltransferases isolated from heart and brain were similar to the properties of the enzyme isolated from liver. Some minor differences in substrate and inhibitor specificities were observed which might suggest slight differences in the active sites of these enzymes.