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Presents some aspects of using infrared spectrophotometry in forensic medical diagnosis of poisonings with some toxic compounds (drugs, organic solvents, etc.). Describes methods of preparing cadaveric material to analysis, examination of microsamples, and assessment of the results of analysis; examples of use of the method are offered.
The purpose of this study was to compare the accuracy of four methods to assess body composition of women. Seventy-seven Caucasian women [mean (+/- SD) age: 31.8 +/- 8.6 years; mass: 59.5 +/- 9.1 kg; stature: 162.4 +/- 6.9 cm; Quetelet Index: 22.5 +/- 3.1 kg/m2] were tested for percent body fat (%BF) with hydrostatic weighing (HW), near-infrared spectrophotometry (NIR), bioelectrical impedance analysis (BIA), and seven-site skinfolds (7-SFs). Compared to %BF with HW (24.9 +/- 6.5%), an analysis of variance revealed no mean differences (P > or = 0.05) among %BF with NIR (26.0 +/- 5.5%), BIA (25.7 +/- 5.8%) and 7-SFs (24.0 +/- 6.0%). The correlations between %BF with HW and NIR, BIA and 7-SF were r = 0.47, r = 0.77, and r = 0.79, respectively (P < or = 0.05), and prediction errors (SEE) were 5.8%, 4.2%, and 4.1%. Comparisons of %BF obtained from machine readings versus those computed from the manufacturer's equation indicated significant differences for the BIA (machine 25.7%, equation 27.8%) and NIR (machine 26.0%, equation 21.5%) methods. We concluded that although the mean %BF differences were small among the four methods, the large SEE values may allow the use of BIA and 7-SFs but not NIR. Inaccuracies of machine readings versus equation-computed %BF indicate that BIA and NIR variables and/or constants in the equations supplied are not identical to those used in machine-generated calculations.
We conducted the present study to determine the effect of endotoxin challenge on brain oxidative metabolism, after finding evidence in previous studies suggesting early uncoupling of mitochondrial oxidative phosphorylation in the rat small intestine during endotoxemia. Twenty male Sprague-Dawley rats were divided into two groups (N = 10 each) which received E. coli endotoxin (20 mg/kg BW) or an equal volume of 0.9% saline (1 ml/kg) by i.v. bolus. Catheter implantation and the subsequent data collection were conducted using isoflurane anesthesia with controlled ventilation. Hemodynamic and metabolic data were recorded for 30 min before and 60 min after endotoxin or saline injection. Tissue oxidative metabolism was monitored in vivo using differential multiwavelength near-infrared spectrophotometry. Optrodes were positioned on either side of the rat's head (transillumination mode) to monitor the redox state of mitochondrial cytochrome a,a3 (AA3) as well as the supply of oxygen to the brain as reflected by tissue oxyhemoglobin (HbO2). In contrast to our previous results for the small intestine, where the decrease in AA3 oxidation level was disproportionately greater than the concomitant HbO2 decrease, we found that the endotoxin-induced impairment in blood flow to the head was associated with a decrease in brain AA3 redox level, which was proportional to the decrease in tissue HbO2. This finding of an apparent oxygen-dependent AA3 redox shift in the brain during endotoxemia is similar to previous findings of others in hemorrhagic hypotension and hypoxic hypoxia. Possible mechanisms for the different mitochondrial AA3 redox responses to endotoxin in the brain and small intestine are discussed.
An analytical method has been developed for determination of 2-ethylhexyl 4-(N-methyl-N-nitrosamino) benzoate (NMPABAO), a nitrosamine contaminant in sunscreen products containing 2-ethylhexyl 4-(N,N-dimethylamino) benzoate (Padimate O). The method involves extraction of NMPABAO by column chromatography followed by liquid chromatographic separation and analysis wit a nitric oxide detector. To confirm the presence of NMPABAO in sunscreen products, the N-nitrosamine was synthesized and its structure was determined by infrared spectrophotometry, nuclear magnetic resonance spectrometry, and mass spectrometry (MS). For method validation, recovery studies were performed on a commercial suntan lotion, cream, and gel. Recoveries of NMPABAO added to representative test samples averaged 83%. The method has an estimated detection limit of 30 ppb. The method was used to analyze 25 commercial cosmetic and sunscreen products containing Padimate O. Eleven products contained NMPABAO at levels ranging from 160 to 21000 ppb. NMPABAO presence in 4 products was confirmed by MS at levels > or = 4000 ppb. The highest levels of NMPABAO were associated with products that contained the nitrite-releasing preservative 2-bromo-2-nitro-1,3-propanediol.
The presence of bone tissue in renal stones has been described for a long time. Two cases of heterotopic ossification are reported in this study. Stone analysis was performed by stereoscopic microscopy, infrared spectrophotometry and fine slice petrographic section and polarized light microscopy. This last technique revealed the existence of osteocytic filling defects inside the stones, an unquestionable sign of mineralized bone tissue.
The BACTEC NR730 blood culture system is a commercially available system which utilizes infrared spectrophotometry to detect bacterial growth in broth media inoculated with the blood specimen. The objective of this study is to compare this system with the conventional system used in our laboratory. A total of 479 blood samples were collected from adult patients in the Klang TAR Hospital and inoculated simultaneously into the two systems. Clinically significant isolates were recovered from 59 (12.3%) specimens by one or both systems yielding a total of 65 isolates of which 41 isolates were recovered in both systems, 18 in BACTEC only and 6 in the conventional system (P < 0.01). Of the 40 (8.3%) blood cultures that were judged as contaminated, 2 were found in both systems, 12 in the BACTEC only and 26 in the conventional system. After 48 hours (day 2) the BACTEC system had recovered 93.2% of the total significant isolates while the conventional system recovered 61.7% only. Our results showed that the BACTEC system yielded more significant isolates in a shorter time and with a lower incidence of contamination as compared to the conventional system.
OBJECTIVE: Evaluate the frequency and assess curative and preventive measures against urinary lithiasis in patients treated with indinavir. PATIENTS AND METHODS: Fourteen HIV seropositive patients who developed severe and acute flank pain were included. Four of the patients receiving 800 mg indinavir t.i.d. had fever (38.5 degrees C) or delayed secretion (> 2 h). Delay from indinavir treatment onset was 1 to 321 days. During the same period, 155 patients had been treated with indinavir. Clinical features, radiology and laboratory results were recorded in addition to an analysis of the lithiasis if possible. RESULTS: Transient moderate renal failure occurred in 8 patients. Mean urine pH was 6. Serum phosphorus, calcium, and uric acid, liver tests and urinalysis were normal. A JJ ureteral stent was inserted in 4 cases due to complications. In all cases, fluids, analgesics and antispasmodics provided favorable outcome. Inversely, nonsteroid antiinflammatory drugs given in 2 patients had a deleterious effect on renal function. The lithiasis was eliminated in 3 cases and infrared spectrophotometry demonstrated a structure compatible with indinavir monohydrate. CONCLUSION: The formation of urinary lithiasis is a frequent complication of indinavir therapy (9%). Hyperhydration and urine acidification are usually successful but emergency drainage is required in approximately 3% of cases. Nonsteroidal antiinflammatory drugs should be avoided due to the risk of renal toxicity. A precise evaluation of fluid intake and diet, drug associations and personal history is needed to recognize patients at risk of recurrent lithiasis formation.
BACKGROUND: To determine the correlation of near-infrared spectrophotometry (NIRS) readings from the liver surface with invasive measurements of blood flow and tissue perfusion parameters in an animal model of endotoxemic shock. MATERIAL/METHODS: Laparotomy was performed in 12 Yorkshire piglets, and ultrasound blood flow probes were placed on the hepatic artery and portal vein. Hepatic vein, portal vein, and femoral artery catheters were inserted for intermittent blood sampling, and a pulmonary artery catheter was inserted via the jugular vein for cardiac output measurements. Near-infrared spectrophotometry optodes were placed across the right hepatic lobe. Endotoxemic shock was induced by continuous infusion of Escherichia coli lipopolysaccharide 055: B5. Pearson correlations were calculated between the perfusion parameters and the near-infrared spectrophotometry (NIRS) readings. RESULTS: After endotoxemic shock induction, liver blood flow decreased from 144 +/- 36 to 62 +/- 24 ml*min(-1)*100 g(-1) and oxygen delivery to the liver decreased from 20 +/- 6 to 7 +/- 4 ml*min(-1)*100 g(-1). Near-infrared spectrophotometry readings of oxyhemoglobin concentration decreased by 11.7+/-15.1 micromol*L(-1), and readings of deoxyhemoglobin concentration increased by 12.3 +/- micromol*L(-1). There were significant correlations (p < 0.05 for r2 > 0.11) between the oxyhemoglobin readings and liver oxygen delivery (r2 = 0.58), liver blood flow (r2 = 0.73) and cardiac output (r2 = 0.80). Deoxyhemoglobin readings highly correlated (p < 0.05 for r2 > 0.11) with mixed venous lactate (r2 = 0.87) and with hepatic vein lactate (r2 = 0.82). CONCLUSIONS: Noninvasive near-infrared spectrophotometry measurements of hepatic oxyhemoglobin and deoxyhemoglobin correlate with liver hemodynamics as well as with global and specific organ perfusion parameters and may serve, in the future, as a useful tool to monitor tissue perfusion in septic patients.
It is now possible to detect quantitative changes in cytochrome aa3 by means of near-infrared spectrophotometry. This technique is also suitable for determining oxidised hemoglobin (HbO2), reduced hemoglobin (Hb), cerebral blood volume, and the redox state of cytochrome aa3 (cyt aa3) in the tissues. The significance of elevated cyt aa3, measured by near-infrared spectrophotometry, is still unclear, so we investigated this question using both near-infrared spectrophotometry and oxygen saturation meters in endotoxemic dogs. Ten anaesthetised mongrel dogs were injected with endotoxin (E. coli 0111: B4 Difco 2 mg/kg i.v.) and the redox state of Hb and cyt aa3 was determined in real time by near-infrared spectrophotometry. The levels of arterial and cisternal venous oxygen saturation were recorded simultaneously by two Oximetrix 3 saturation meters to calculate the cerebral arterial and venous oxygen saturation difference (Sata-vO2D) in real time. HbO2 decreased along with the fall in mean arterial pressure and remained at a low level, while Hb increased and remained at a high level. The cerebral blood volume decreased in the endotoxic early stage and then returned gradually towards baseline. Cyt aa3 showed an increase following endotoxin injection and maintained an oxidised form. The cerebral Sata-vO2D rose to about three times the control level. From these observations, an increase of oxidised cytochrome aa3 after endotoxin administration seems to be a compensatory protective effect in response to the cerebral oxygen demand rather than over-oxygenation or hyperoxia.
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Near infrared spectrophotometry provides noninvasively real-time information on cerebral oxygenation and cerebral blood volume. Using this method of spectrophotometry we investigated the adequacy of collateral circulation during cross-clamping of the internal carotid artery in patients who underwent carotid endarterectomy. In 15 patients, oxy-hemoglobin, deoxyhemoglobin and total hemoglobin were monitored continuously by near infrared spectrophotometry at the ipsilateral frontal area on the operated side. Changes in these parameters following temporary cross-clamping of the internal carotid artery were evaluated. The stump pressure of the internal carotid artery was measured in every patient. Only the maximum decrease in oxy-hemoglobin during cross-clamping of the internal carotid artery correlated significantly with the stump pressure of the internal carotid artery. Changes in oxy-hemoglobin during cross-clamping of the internal carotid artery demonstrated three patterns; no change or minimally decreased (4 patients), decrease with recovery (4 patients), and decrease without recovery (7 patients). The stump pressure of the internal carotid artery in patients who had no recovery of their decreased oxy-Hb was significantly lower than that in any other pattern (p < 0.01, Mann-Whitney U analysis). Patients who experience decrease in oxy-Hb without recovery following cross-clamping of their internal carotid artery may have poor collateral circulation and therefore may develop cerebral ischemia.
Larger and more perfect crystals in bone mineral from osteoporotic women have been described using biophysical methods. In search of the cause of this change, both chemical analysis and infrared spectrophotometry were used on iliac crest bone biopsies from 19 postmenopausal osteoporotic women. These women had each had a vertebral crush fracture and had a urinary hydroxyproline: creatinine ratio greater than 0.012. Lower than normal trabecular bone magnesium content and larger and more perfect crystals in trabecular bone mineral identified on infrared spectrophotometry were found in 16 out of the 19 women. Magnesium deficiency was confirmed by Thoren's magnesium load test in this subgroup of 16. Higher than normal bone magnesium content and smaller and less perfect crystals in bone mineral were found in five postmenopausal uremic women tested.
Seventeen cases of urinary calculi analyzed by infrared spectrophotometry were found to be composed entirely or nearly entirely of bihydrated calcium hydrophosphate. The observations are summarized here. This type of stone occurs with a frequency of about 1% (0.85% in our experience) of all urinary calculi, predominantly in men (14 of our 17 cases). Diagnosis is based on the physical and chemical analysis of the stone and on infrared spectrophotometry. Most of these stones are pure or nearly pure compounds. The macroscopic aspect of the stones or fragments of stones can guide diagnosis. These stones are cream coloured stones with a smooth regular outer surface. Broken fragments show the same cream colour, sometimes with strips radiating from the centre of the fracture surface. Radiologically, these stones are homogeneously radio-opaque, often oval-shaped with a regular outline. Blood tests can demonstrate suspected or proven hyperparathyroidism (4 out of 10 cases in our 17 observations) with hypercalcemia, hypophosphatemia and hypercalciuria. Complementary examinations may be needed to search for a parathyroid adenoma. With or without hyperparathyroidism, 24-h urinalysis usually shows hypercalciuria up to ro over 500 to 600 mg/24 h. Crystallization usually occurs in the upper urinary tract, in the bladder or in indwelling catheters. These stones are extremely hard and are difficult to break in vitro. To be successful, lithotripsy requires prolonged treatment: up to 3000 to 6000 shockwaves at 22-23 kv with the Dornier apparatus. Despite the notion of hypercalciuria, the pathogenesis of bihydrated calcium hydrophosphate calculi remains to be elucidated.
The mechanism of the inclusion of tropaeolin OO (TPOO) and beta-cyclodextrin (beta-CD) has been studied by spectrophotometry. The inclusion depth of the guest molecule in the host molecule was demonstrated by infrared spectrometry. Effect of the pH, concentrations of beta-CD, solvents and ionic strength on the inclusion of TPOO and beta-CD were examined. The result showed that TPOO reacts with beta-CD to form a 1:1 host-guest complex with an apparent formation constant of 1.50 x 10(3) l mol(-1). The thermodynamic parameters of inclusion reaction, DeltaG degrees , DeltaH degrees and DeltaS degrees were obtained.
PURPOSE: To evaluate the effect of two commercially available carbamide peroxides bleaching agents, Opalescence and Nite-White, in concentrations of 10, 15 and 16%, on enamel. MATERIALS AND METHODS: Vickers hardness measurements (VH) were made at the surface and 110 microns below the surface on human enamel samples that were treated for 5 or 10 days, 6 hrs/day. Furthermore, infrared spectrophotometry (IR), Fourier transform infrared spectrophotometer (FTIR) and X-ray diffraction (XRD) measurements were performed after the VH measurements were completed. RESULTS: Using a one-way ANOVA, statistically significant differences in VH could be established between surface and subsurface VH values. For all groups, including the control group, the surface VH values were statistically significantly higher than subsurface VH. IR, FTIR and XRD established a change from hydroxyapatite to primary calcium ortho phosphate [Ca(H2PO4)2] for all experimental groups except for 10% Opalescense tested for 5 or 10 days.
A quadruple wavelength method to monitor the changes in concentration of oxygenated and deoxygenated hemoglobin and the redox state of cytochrome oxidase within a living tissue is presented. The expected advantages of this technique over the triple wavelength method are (i) that it can compensate for the light scattering change of tissue itself or for instabilities of light source and photomultiplier, (ii) that it can treat the optical properties of the red blood cell in a tissue in the same way as in an in vitro model system, and (iii) that it requires no estimation of the absorption coefficient of cytochrome oxidase in situ.
A major vitamin D metabolite was isolated in pure form from the blood plasma of chicks either maintenance levels or large doses of vitamin D3. The isolation involved methanol-chloroform extraction and five column chromatographic procedures. The metabolite purification and elution position on these columns were followed by a competitive protein binding assay. The metabolite was identified, using high- and low-resolution mass spectrometry, 270-MHz proton nuclear magnetic resonance spectrometry, ultraviolet absorption spectrophotometry, Fourier transform infrared spectrophotometry, and specific chemical reactions, as 3 beta,-25-dihydroxy-9,10-seco-5,7,10(19)-cholestatrieno-26,23-lactone. The trivial names 25-hydroxyvitamin D3 26,23-lactone or calcidiol 26,23-lactone are suggested for this compound.
A new vitamin D3 metabolite was isolated in pure form (18.2 micrograms) from the serum of rats given large doses (two doses of 26 mumol/rat) of vitamin D3. The new metabolite has been unequivocally identified as 3 beta, 25-dihydroxy-9,10-seco-5,7,10(19)-cholestatrieno-26,23-peroxylactone by ultraviolet absorption spectrophotometry, Fourier transform infrared spectrophotometry, mass spectrometry, field desorption mass spectrometry, and specific chemical reaction with triphenyl phosphine. The stereochemical configuration at the C-23 and c-25 positions of the 25-hydroxyvitamin D3-26-23-peroxylactone was definitely determined to be the 23(S)25(R),25-hydroxyvitamin D3-26,23-peroxylactone is suggested for this metabolite. The isolation involved chloroform-methanol extraction and four column chromatographic procedures. The metabolite purification and elution position on these columns were followed by UV measurement at 264 nm. This metabolite was ultimately resolved from the previously known 25-hydroxyvitamin D3-26,23-lactone by high pressure liquid chromatography using a Zorbax Sil column. The 25-hydroxyvitamin D3-26,23-peroxylactone was converted upon storage at room temperature or -20 degrees C into the 25-hydroxyvitamin D3-26,23-lactone. Since under the conditions of this isolation only the 26,23-peroxylactone and no 26,23-lactone of 25-hydroxyvitamin D3 was present in the rat serum, this suggests that the 25-hydroxyvitamin D3-26,23-peroxylactone is the naturally occurring metabolite.