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At least 181 records · Page 10Linked to original sources
PubMed2006

Infrared spectrophotometry of intraluminal meconium calculi in a neonate with imperforate anus and rectourethral fistula.

BACKGROUND/PURPOSE: Intraluminal meconium calculi are a rare cause of neonatal abdominal calcifications in patients with anorectal malformations. To investigate their pathogenesis, we performed infrared spectroscopic analysis of meconium-calcified lesions. METHODS: Meconium calculi were collected from the colostomy in a newborn patient with imperforate anus and rectourethral fistula. The potassium bromide method was employed to obtain the infrared absorption spectrum of the meconium calculi. RESULTS: The wavelength pattern of the meconium calculi exhibited 4 specific peaks at 1570, 1390, 1105, and 1005 cm(-1) between 22% and 45% transmittance values. The unique absorption spectrum exclusively indicated ammonium hydrogen urate (C(5)N(5)O(3)H(7)), having the combined constituents of ammonium and uric acid. CONCLUSIONS: These results suggest that the intraluminal meconium calculi were originally derived from meconium and fetal urine. The stasis of meconium passage and fetal urine mixing through the rectourethral fistula in a low-pH condition was deduced to be the main cause of this rare stone formation.

Anus, Imperforate↗
PubMed1992

[Composition of urinary calculi defined with precision by infrared spectrophotometry].

In order to reduce the relapse of the disease lithiasis, it is very important to have a very good idea about the growth process of the urinary stone. The greatest concern is the recuperation and the profound analysis of the nucleus and the peripheral layers. The preceding morphological study of the stone fragments in combination with the infrared spectrometry is the only manner to know all about the urinary calculus. Many information is lost if only an overall infrared spectrum of the sample is taken.

Calcium Oxalate↗
PubMed1990

[Near infrared spectrophotometry--a non-invasive, continuous method for monitoring of cerebral status in newborn infants].

Hypoxic-ischaemic injury to the brain is the commonest cause of permanent neurodevelopmental disability in the very preterm and other children who survive after neonatal intensive care. Non-invasive techniques are therefore needed to examine the mechanisms of damage to the brain. Near infrared spectroscopy provides continuous cot-side information about cerebral oxygenation and metabolism in sick preterm infants by measurements of oxyhaemoglobin, deoxyhaemoglobin and oxidized cytokrom aa3. The cytokrome aa3 signal may, however, be artifactual due to interference from oxyhaemoglobin. Future investigations may clarify this problem.

Brain Damage, Chronic↗
PubMed1991

[Study on polymorphism of gossypol by infrared spectrophotometry and X-ray diffraction].

The polymorphism of gossypol has been investigated by IR spectrophotometry and X-ray diffraction. Nine samples of gossypol crystallized from mixed solvent of ether, ethanol and water (1:2:2), five samples from chloroform and ten samples from petroleum ether (bp 60-90 degrees C) were determined. Significant differences in the infrared spectra of gossypol crystallized from three solvents were observed near 3500 cm-1. The spectrum of gossypol crystallized from mixed solvent of ether, ethanol and water (mp 183-184 degrees C) showed bands at 3500 (sh), 3470, 3375 cm-1; that from chloroform (mp 198-199 degrees C) at 3455, 3415 (sh) cm-1 and that from petroleum ether (mp 213-214 degrees C) at 3510, 3495, 3430 (sh), 3410 cm-1. Moreover, the spectra of the three forms of gossypol showed slightly different bands at 780 and 600-400 cm-1. Gossypol crystallized from the three solvents showed the same infrared spectra after being crystallized from acetone. Significant differences in the X-ray diffraction pattern of gossypol crystallized from the three solvents were also observed. Angles, intensities and D-values of most of the X-ray diffraction peaks were listed.

Crystallization↗
PubMed2003

The influence of a clear layer on near infrared spectrophotometry: comparison of measurements in a liquid neonatal head phantom to infants in vivo.

Near infrared spectrophotometric (NIRS) algorithms to determine the tissue oxygen saturation (TOI) assume a semi-infinite, homogenous tissue geometry. At the head, the clear cerebrospinal fluid (CSF) layer may violate this assumption. The aim was to estimate the error in the TOI values caused by the CSF layer in vitro and to confirm the results in vivo. The liquid phantom mimicking the neonatal head, consisted of a spherical shell of silicone filled with a liquid solution (1% Intralipid, 60 mumol/l haemoglobin, yeast) and a clear layer imitating CSF. The solution was oxygenated and deoxygenated, while measuring its TOI and pO2. Without clear layer the mean TOI was 90.9 +/- 0.5% at pO2 > 18 kPa and decreased to 26.0 +/- 1.3% at pO2 = 0 kPa. With a clear layer the TOI increased from 27.8 +/- 0.8% at pO2 > 18 kPa to 68.0 +/- 0.8% at pO2 = 0 kPa. The clear layer caused a large error in the TOI. In ten mechanically ventilated infants (postnatal age 0.03 to 8 months) the TOI (at the head) and arterial oxygen saturation (SaO2) were measured while the inspired oxygen fraction was altered. The TOI was always positively correlated with the SaO2 (mean slope linear regression = 0.89, r2 = 0.62). Thus an adverse effect of the CSF layer on TOI measurements can be excluded for infants. The CSF layer is not modelled correctly in the phantom.

Head↗