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The method of blood-free isolated perfused rat brain was described, of which EEG was within the normal range. The simultaneous measurement of heme a+a3 and copper in cytochrome oxidase could be performed under the various conditions such as graded hypoxia and seizure. The relationship between these two chromophores in the brain was same to that of isolated mitochondria.
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Lyophilized preparations of sterile broth, broth used for cultivation of enteropathogenic E. coli strains from which endotoxin and enterotoxin had been removed, were prepared for spectrophotometry by mixture with potassium bromide, and examined in heavy water. Despite basic biochemical differences, all the preparations showed similar or identical curves, with the same absorption maximum and wave length. The substances present in broth (proteins, lipids, sugars, etc.) were so dominant that that completely masked substances specific for E. coli and its toxins. Spectrophotometry revealed only the pattern belonging to broth, so that toxins can be only examined by this method after they have been separated from the broth. It is hoped to do this in the future.
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A standard procedure for the identification of volatile solvents in the gas phase by infrared spectrophotometry has been modified and applied to the analysis of gastric contents. A 10 ml sample of the vapor from the gastric aspirate is removed with a hypodermic syringe, injected on a spectrophotometer from 2.5 to 15 nm. The sample is then identified by comparison with known reference spectra. Solvent concentrations cen be estimated by comparing the ratios of the major peaks.
Percent body fat (%BF) was assessed in 171 men with underwater weighing (UWW), seven-site skinfolds (7 SF), and near-infrared spectrophotometry (NIR). NIR was determined at eight sites, including biceps, triceps, axilla, chest, abdomen, suprailium, subscapula and thigh. Analysis of variance and Dunnett's post-hoc procedure revealed that NIR significantly (P less than 0.05) underpredicted %BF when using the biceps (12.9%), chest (11.3%), abdomen (10.2%), subscapula (11.3%) and thigh (9.9%) sites compared to the criterion %BF measured with UWW (13.4% +/- SD = 6.49). %BF with 7 SF was only 0.3% higher than %BF with UWW (r = 0.94, standard error of estimate = 2.9%). Correlation coefficients between SF thickness and NIR optical density readings at 940 nm (OD1) and 950 nm (OD2) wavelengths ranged from r = -0.30 (subscapula) to r = -0.67 (biceps) for OD1 and r = -0.39 (axilla) to r = -0.68 (biceps) for OD2. Multiple linear regression showed that the OD readings were not significant predictors of UWW %BF when using body mass, stature, activity level, and frame size as predictors, except for the OD2 reading at the biceps site. Stepwise regression revealed that NIR OD readings did not predict additional variance in %BF beyond mass, stature, activity level, frame size, or 7 SF. It was concluded that 7 SF are better predictors of %BF than NIR, and that NIR at multiple sites is inconsistent in assessing body composition.
The hemoglobin oxygenation state and the redox state of Cyt.ox. in the rat brain during and after seizure induced by PTZ were measured by using near-infrared spectrophotometry. PTZ administration caused transient reduction of Cyt.ox. in the brain, which might be a trigger for the increase of CBF during seizure. In postictal phase, although BP remained high, Cyt.ox. was in the certain reduced state, which might be due to A-V shunt. Hypoxic loading during seizure caused more reduction of Cyt.ox. than under non-epileptic conditions, which meant that seizure even under mild hypoxic conditions could cause severe hypoxic brain damage.
Numerous clinicians criticise the insufficiency and imprecision, and the incoherency of the analyses of biological calculations by the usual clinical methods and thus frequently avoid prescribing such an examination. The authors propose the application of a physical method, infrared spectrophotometry for the qualitative and semi-quantitative determination of the composition of stones of all origins. They recall the often heterogeneous structure of the stones and emphasise the importance which they attribute of differential analysis by separate zones during careful dissection, the results of which may orient the therapeutic attitude of the clinician. The differentiation of a few crystalline structures and the study of complex mixtures are dealt with in the form of characteristic infrared spectra. The advantages and limits of the method compared with other technics of analysis are discussed.
Fast scanning near infrared spectroscopy (680-1050nm) was utilized to evaluate human forearm muscle oxygenation in 15 adults volunteers. Spectra were recorded in hypoxic hypoxia, ischemia and venous outflow restriction. Derivative spectra were performed with the aim to obtain a quantitative information of Hb/Mb oxygen saturation free from volume and scattering changes. The absorption spectra O.D. demonstrate an increase of deoxy-Hb/Mb in hypoxic condition with a moderate volume changes. In ischemia a rapid Hb/Mb desaturation occurred until a plateau was reached at 4th min. The cuff release was followed by hyperemia with Hb volume raise and oxy-Hb/Mb increase above the control. Spectral data support the hypothesis that derivative NIRS can be used to identify muscle oxygenation changes.