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PubMed1996

Interpretation of BOLD MRI signals in rat brain using simultaneously measured near-infrared spectrophotometric information.

The purpose of this paper is to investigate the origin of the signal changes in the blood oxygenation level dependent effect (BOLD) and the influence of oxygen metabolism by utilizing near-infrared spectrophotometry (NIRS), which can measure deoxyhemoglobin (deoxyHb) content in blood vessels and redox states of cytochrome oxidase in whole tissue. Simultaneous MRI and NIRS measurements of the rat head were performed by changing oxygen concentrations in the inhalant gas. The signal intensity based on the BOLD effect depended on the influence of both arterial and venous blood deoxygenation in the brain, whose relative contributions differed at various points. In this paper, it is noteworthy that the differential apparent transverse relaxation rate between two conditions in the brain areas was linearly correlated with deoxyHb content determined by NIRS, except in severe hypoxia, and that no reduction of cytochrome oxidase occurred under the same conditions. These results indicate that the influence of hemodynamic changes on the signal intensity of the BOLD effect, and therefore functional MRI, can be elucidated by the NIRS information to determine actual changes of blood deoxygenation and blood volume.

Animals↗

PubMed1988

Physical characterization of two oxyphenbutazone pseudopolymorphs.

Two pseudopolymorphic forms of oxyphenbutazone, a benzene solvate (Solvate B) and a cyclohexane solvate (Solvate C), were prepared by recrystallization from benzene and cyclohexane, respectively. The forms were characterized by means of differential scanning calorimetry, thermogravimetry, infrared spectrophotometry, X-ray powder diffraction, and thermomicroscopy, as well as powder and intrinsic dissolution rates. The dissolution rates of the two pseudopolymorphs were shown to be superior to those of the anhydrate, hemihydrate, and monohydrate which were previously reported. A brief stability report is included.

Calorimetry, Differential Scanning↗

PubMed1989

Physical and structural comparison of oxyphenbutazone monohydrate and anhydrate.

Two crystal forms of oxyphenbutazone (a monohydrate and an anhydrate) were prepared by recrystallization. The forms were characterized by means of differential scanning calorimetry, thermogravimetry, infrared spectrophotometry, X-ray powder diffraction patterns, thermomicroscopy, scanning electron microscopy, as well as powder and intrinsic dissolution rates. The crystal structure of the anhydrate has been elucidated and compared with that of the monohydrate.

Calorimetry, Differential Scanning↗

PubMed1989

Primary cholesterol hepatolithiasis.

Stones extracted from patients with hepatolithiasis were analysed by infrared spectrophotometry. Cholesterol stones containing 70% or more cholesterol were found in 12 out of 55 cases. Judging from the lodging site of the stones, the degree of dilatation of the cystic duct, and the presence of cholecystitis, five of the cases were considered to be cholesterol stones produced in the liver. Two out of the five cases were a 44-year-old female and a 46-year-old female, respectively, with normal bifurcation of intrahepatic ducts, and stones were found in the lateral branches of dilated cystic bile ducts. The other three were 2 males and 1 female with an average age of 33. In these cases, the posterior descending branch bifurcated from the left hepatic duct, and stones were lodged in the dilated bile ducts distal to the junction of the left hepatic duct and the posterior descending branch. It is our conclusion that at least the former two were cases of "primary cholesterol hepatolithiasis" in view of the shape of the stones conforming to the hepatic duct, their easy morcellation, and the high cholesterol contents.

Adult↗

PubMed1975

Interaction of water with egg lecithin in benzene solution.

Benzene solutions of purified egg lecithin, with small amounts of water added, have been examined by 60 MGz and 100 MHz NMR spectroscopy, infrared spectrophotometry and phase contrast microscopy. The transverse relaxation times of the water, N-methyl and O--H protons are dependent on water concentration. This dependence changes sharply for the water proton at a level of one water molecule per lecithin monohydrate molecule. These results do not fully agree with those reported by other workers. Four mathematical models are examined which could account for the behaviour of the water protons. Models which assume a constant transverse relaxation time for water protons above a level of one water molecule per lecithin molecule cannot predict the behaviour observed. It is sufficient to assume that water protons above this concentration have a single relaxation time which is a linear function of water concentration. The added water associates primarily with the phosphate in the lecithin head group. Above nine water molecules per lecithin monohydrate molecule free water is present in the system.

Benzene↗

PubMed1990

Ascaris lumbricoides: detecting its metabolites in the urine of infected people using gas-liquid chromatography.

Substances dissolved in the urine of people infected with Ascaris lumbricoides were extracted and detected by gas-liquid chromatography. The ratios of the areas of the peaks produced by two substances extracted from urine to the area of the peak of solvent were found to be significantly correlated with the worm burden. A chemical analysis of the predominant substance by infrared spectrophotometry and proton magnetic resonance spectrometry indicated that it was 2-methyl-butyramide. The chemical properties of the other substance indicated that it was 2-methyl-valeramide. These substances are likely to be derivatives of two acids known to be end products of the carbohydrate metabolism of Ascaris.

Amides↗

PubMed1992

Chromatographic analysis of cis- and trans-mevinphos in poisoned wildlife.

A method is described for the analysis of the cis- and trans-isomers of mevinphos in baits and avian tissues. The procedure involves extraction of the mevinphos isomers with acetone-dichloromethane (1:1) followed by clean-up on alumina. Bait samples were initially screened by thin-layer chromatography and identity of extracts confirmed by infrared spectrophotometry and gas chromatography-mass spectrometry.

Animals↗

PubMed1992

A study of hydrogen exchange of monoclonal antibodies: specificity of the antigen-binding induced conformational stabilization.

Amide-hydrogen exchange of three anti-yeast iso-1-cytochrome-c IgG monoclonal antibodies and the Fab, prepared from one of them, were studied by infrared spectrophotometry in the presence and absence of the deuterated immunogen and evolutionarily related species (the deuterated immunogen contained a population of a dimer. Each subunit of the dimer appeared to bind to the antibodies in a manner similar to the monomer). The number of hydrogens of the antibodies whose exchange was suppressed on binding to the immunogen was found to exceed that estimated for the residues shielded by the immunogen. Analysis of the data suggests that such suppression of hydrogen exchange occurs mainly for the Fab domains, but not for the Fc. One of the antibodies showed two distinct classes of amide-hydrogens. Class-1 hydrogens (approx. 36/site) exchange faster than class 2 (approx. 37/site). The exchange of class-1 hydrogens was suppressed by binding to the immunogen, but not to the evolutionarily related species. The exchange of class-2 hydrogens was suppressed by binding to the evolutionarily related species, as well as to the immunogen. Thus, the suppression of exchange of class-1 hydrogens appears to occur by some kind of conformational stabilization, the mechanism of which differentiates between the deuterated immunogen and the evolutionarily related species. Evidence suggests that the trans-interactions of the Fab domains may modulate the hydrogen exchange. If it is assumed that the antigen-binding strengthens the trans-interactions in such a way that the exchange of the slower exchanging hydrogens is suppressed, this could explain the suppression of exchange of class-2 hydrogens.

Amides↗

PubMed1993

Detection of dynamic changes in cerebral oxygenation coupled to neuronal function during mental work in man.

Changes in the oxygenation state of brain hemoglobin during mental work were monitored in real time (time resolution: 1 s) using near-infrared spectrophotometry in 14 healthy volunteers. In a younger group (age range 22-30 years, n = 12), the subjects finding difficulty in solving a problem were accompanied by significant increases in both oxygenated hemoglobin and total hemoglobin, while the subjects making a correct answer without difficulty showed no significant changes in hemoglobin oxygenation. When compared with those younger subjects, observations on the older subject demonstrated a decrease in oxygenated hemoglobin and a reciprocal increase in deoxygenated hemoglobin, unaccompanied by changes in total hemoglobin.

Adult↗

PubMed2004

Oxygenation and hemodynamics in left and right cerebral hemispheres during induction of veno-arterial extracorporeal membrane oxygenation.

OBJECTIVE: Oxygenation and hemodynamics in the left and right cerebral hemispheres were measured during induction of veno-arterial extracorporeal membrane oxygenation (VA-ECMO). STUDY DESIGN: Using near infrared spectrophotometry, effects of right common carotid artery (RCCA) and right internal jugular vein (RIJV) ligation and start of VA-ECMO on concentrations of oxyhemoglobin, deoxyhemoglobin, and cerebral blood volume (CBV) were evaluated in 10 newborn infants. Mean cerebral blood flow velocity (CBFV) in the major cerebral arteries was compared before and after the start of VA-ECMO (pulsed Doppler ultrasonography). RESULTS: RCCA ligation caused a decrease in oxyhemoglobin concentration and an increase in deoxyhemoglobin concentration. RIJV ligation caused no changes. Sixty minutes after the start of VA-ECMO, oxyhemoglobin concentration and CBV had increased, and deoxyhemoglobin concentration had decreased. There were no differences between the hemispheres. Mean CBFV had increased in the left internal carotid artery, and it increased equally in both middle cerebral arteries. Flow direction was reversed in the right internal carotid artery. Three patients had asymmetric cerebral lesions, not related to differences in the measurements between the cerebral hemispheres. CONCLUSION: The initiation of VA-ECMO causes changes in cerebral oxygenation and hemodynamics but without a difference in effect on left and right cerebral hemispheres.

Blood Pressure↗

PubMed1988

Effects of crying on cerebral blood volume and cytochrome aa3.

To determine if crying alters cerebral hemodynamics and oxidative metabolism in the brain, near infrared spectrophotometry was used to assess relative changes in cerebral blood volume and the oxidation-reduction state of cytochrome aa3. Thirty-six crying episodes were observed, 20 in healthy infants and 16 in infants with respiratory problems. Throughout all crying episodes cerebral blood volume and oxidized cytochrome aa3 demonstrated oscillatory fluctuations every 10 to 20 seconds, with maximum changes during prolonged exhalations. In 86% of episodes baseline blood volume rose and remained elevated during the cry. The relative content of deoxyhemoglobin in cerebral blood also rose, indicating that venous blood is the major contributor to the increase in blood volume. Changes in baseline cytochrome aa3 oxidation varied with the presence of lung disease and with the chronologic age of the infant. Cytochrome reduction with crying occurred significantly more often in infants with respiratory problems than in healthy infants. Cytochrome aa3 became more oxidized in 82% of crying episodes in healthy infants older than 3 days of age, but no change in cytochrome oxidation was usually noted in those younger than 3 days. Thus crying alters cerebral blood volume in all neonates in a pattern consistent with cyclic obstruction to cerebral venous return; it decreases cerebral oxygenation in infants with respiratory problems.

Blood Volume↗

PubMed1999

Formation of ondansetron polymorphs.

We used differential scanning calorimetry, infrared spectrophotometry and 1H nuclear magnetic resonance imaging to search for polymorphs of ondansetron. Samples were tested under different conditions of temperature, pulverization and pH, and in different solvents. The factors identified as able to cause the formation of polymorphs were heating to different temperatures for different times, and the use of ethanol and methanol as solvents.

Antiemetics↗

PubMed1999

Cyclical fluctuations in blood pressure, heart rate and cerebral blood volume in preterm infants.

Many recently published papers describe cyclical changes of cerebral circulatory variables, mainly in cerebral blood flow velocity (CBFV) performed with Doppler sonography. In this paper we focus on another important variable of cerebral circulation: on cerebral blood volume (CBV) measured by near infrared spectrophotometry (NIRS). In a retrospective analysis of NIRS measurements in 20 preterm infants (median 27 3/7 weeks of gestation), the dominating frequencies and prevalence of cyclical changes of CBV and its possible correlation with peripheral circulatory variables (mean arterial pressure and heart rate) was examined. In 19 out of the 20 infants cyclical changes of CBV were found within a frequency range of 2-4.7 cycles/min which is comparable to the results of the Doppler studies describing fluctuations in CBFV. A dominating frequency of heart rate (HR), was found only in 12 out of 20 infants, and it was with 2.1-3.8 cycles/min in a similar range compared to CBV. In mean arterial blood pressure (MABP), however we detected cycles with longer periods every 1-2.5 min in 14 out of 20 infants. There was a significant coherence between MABP/CBV and HR/CBV. The area under the coherence curve, however, was significantly larger between MABP and CBV as compared to HR and CBV (P = 0.0007, Wilcoxon signed-rank test).

Blood Pressure↗

PubMed1998

Quality evaluation of radiographic contrast media in large-volume prefilled syringes and vials.

RATIONALE AND OBJECTIVES: The authors compared the particle contaminations of radiographic contrast media packaged in large-volume prefilled syringes and vials. MATERIALS AND METHODS: Particle counting was performed for four contrast media packaged in large-volume prefilled syringes (iohexol, ioversol, ioversol for angiography, and ioxaglate) and three contrast media packaged in vials (iohexol, ioversol, and ioxaglate). X-ray emission spectrometry was performed to characterize the individual particles. The amount of silicone oil in the syringe was quantified with infrared spectrophotometry. RESULTS: The particle contamination in syringes containing ioversol was higher than that in syringes containing iohexol or ioxaglate. Particle contamination in the vials was relatively low, except with ioxaglate. X-ray emission spectrometry of the components of the syringe and vial showed that the source of particles was internal material released from the rubber stopper or inner surface. CONCLUSION: The particle counts for contrast media packaged in syringes and vials varied considerably among the different contrast media and were related to the amount of silicone oil on the inner surface and rubber piston of the syringe.

Contrast Media↗

PubMed1983

Infrared spectrometry and Raman microprobe in the analysis of urinary calculi.

Infrared spectrophotometry and Raman spectroscopy, thanks to the laser molecular microsond (MOLE), are two analytical techniques particularly well suited to a precise analysis of the composition and structure of urinary calculi. They both showed noteworthy efficiency in their ability to recognize the various crystalline or amorphous mineral and organic species. The MOLE permits analysis of crystals 1 mu in size, demonstrating its usefulness in the study of calculi nuclei as well as in the study of urinary crystals. These analyses are a very important source of information about conditions of crystalline nucleation and growth as well as about ions and molecules which can take place in the formation and the evolution of the diverse crystalline phases. On the clinical level, these data can contribute to a better comprehension of the formation of every stone.

Apatites↗

PubMed1984

Calcium oxalate dihydrate formation in urine.

Factors that promote the formation of calcium oxalate dihydrate (COD) in urine were investigated. Crystals resulting from the incubation of 25-ml aliquots of the solution to be tested and 1 ml of 0.05 M ammonium oxalate were examined by infrared spectrophotometry. With reference spectra of known mixtures, the fractional content of COD could be estimated. At pH 6.5, only COD formed in human urine. In a supersaturated inorganic solution of calcium oxalate, the percentage of COD was 7.5 +/- 1.4. Pyrophosphate (1 to 8 X 10(-5) M), citrate (10(-4) to 2 X 10(-3) M), RNA from yeast (5 X 10(-9) to 0.5 X 10(-7) M), or heparin (2 X 10(-9) to 2 X 10(-7) M) added to a supersaturated solution of calcium oxalate increased the percentage of COD proportional to the concentration of the additives. Chondroitin sulfate and magnesium had no effect. An increase in pH increased the formation of COD in inorganic solutions containing citrate, pyrophosphate, and heparin and in undiluted urine. RNA-citrates and citrate-pyrophosphate mixtures showed additivity. Urine showed an effect that was inversely proportional to its dilution. Substances that promote COD formation in this system had their phase-stabilizing effects at concentrations normally found in urine. Further, these same substances are known inhibitors of calcium oxalate crystal formation. With both inhibition and phase stabilization, there is additivity of effects, and changes in pH alter the response.

Adult↗

PubMed2000

Cerebral near infrared spectroscopy for the measurement of indocyanine green elimination in cirrhosis.

BACKGROUND: Indocyanine green (ICG) clearance is a useful indicator of hepatic function but most measurement methods are invasive. AIM: To validate a less invasive technique using cerebral near infrared spectrophotometry (NIRS) to measure ICG elimination, and to compare it with the established methods for the determination of ICG clearance in a group of normal controls and patients with cirrhosis. METHOD: NIRS was used to measure ICG elimination in 41 cirrhotic patients and nine healthy volunteers. The first 13 of the cirrhotic patients also had their ICG clearance measured by the conventional spectrophotometric technique. RESULTS: NIRS ICG elimination rate (ICG-k) and spectrophotometry ICG-k values correlated strongly (r= 0. 828, P < 0.001, n=13). There was a significant reduction in the mean NIRS-k in cirrhotic patients and within Child-Pugh classes A, B, and C (P < 0.001). CONCLUSION: Measurement of ICG elimination by the NIRS method is at least as reliable as the conventional spectrophotometric technique in normals and in patients with cirrhosis. This technique merits further development for use as a bedside, less invasive liver function test.

Coloring Agents↗

PubMed2000

Phosphoglyceride crystal deposition disease.

An extremely rare phosphoglyceride deposition disease is reported. A healthy 62-year-old Japanese woman suffered from tumors that repeatedly appeared in injured soft tissues for more than 20 years. No immunologic disorders or abnormal laboratory data were found. Histology showed foreign body granulomas consisting of macrophages surrounding yellowish-white crystals. The crystals were weakly positive by von Kossa's method, were dissolved in 30% acetic acid with gas, and were easily dissolved in 0.1 N NaOH or potassium hydroxide, losing their crystal structure. Using a scanning electron microscopy X-ray microanalyzer, phosphorus and calcium peaks were detected. Phosphoglycerides were detected by microscopic infrared spectrophotometry and microsampling mass spectrometry. The gold hydroxamic acid method for detecting phosphoglyceride showed strong positive staining in the crystals. Based on the above analyses, the deposited crystals were regarded as phosphoglyceride, which bound calcium as a counter ion. The crystals tended to be deposited at sites of injury, where macrophages had accumulated. The patient had received many injections of a medicine made from alcohol extract from bovine liver. We suspect that this medicine was related to the cause of the deposition as the deposition repeatedly appeared at the site of the injections.

Connective Tissue↗