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Biomedical subjects

D Hess

Publications and source records attributed to D Hess.

At least 181 records · Page 10Linked to original sources
PubMed1989

Assay of pyridoxal-5'-phosphate, pyridoxal and pyridoxic acid in biological material.

The two vitamin B6-vitamers having an aldehyde function are oxidised to the corresponding acids and subjected to an HPLC separation on an RP 18 phase with a solvent consisting of 5% methanol in phosphate buffer at pH 3.5. The detection is carried out by fluorometry with excitation at 318 nm and emission at 418 nm. The peaks obtained correspond to pyridoxic acid 5'-phosphate and pyridoxic acid. Pyridoxal-5'-phosphate is determined as pyridoxic acid 5'-phosphate. Pyridoxal is determined as pyridoxic acid by subtracting the amount of pyridoxic acid already existing before oxidation.

Amniotic Fluid↗
PubMed1988

The carbohydrate composition of human serum amyloid P component.

The carbohydrate moiety of human serum amyloid P component was analyzed and found to consist of equal amounts of galactose and mannose (total 4.0%), of glucosamine and galactosamine in a ratio of 7:1 (total 2.7%) and sialic acid (3.9%). It should be noted that this is the first report on the separate quantification of the neutral hexoses and the demonstration of the presence of galactosamine. The contents of glucosamine and galactosamine suggest that this protein possesses both an N- and an O-glycan.

Carbohydrates↗
PubMed1988

Glycosaminoglycan content in neonatal rat aortic smooth muscle cell cultures.

In the present study the biosynthesis of glycosaminoglycans (GAGs) by neonatal rat aortic smooth muscle cells in culture was studied. Heparan sulfate (HS) was the predominant GAG of the cell layer accounting for 32-49% of the total GAGs depending on the time in culture. The presence of low sulfated chondroitin sulfate (LSC) in aortic smooth muscle cell cultures is reported here for the first time. The effect of ascorbate on the synthesis and accumulation of these macromolecules resulted in a relative increase of C4S and DS in the cell layer. In contrast, the distribution of the GAGs which were secreted into the medium was not significantly effected by the addition of ascorbate. While HS was always found to be a minor component, the other GAGs were present in about equal concentrations. The total GAG accumulation in the medium was much greater (91-97%) than that of the cell layer (3-9%) indicating that the cells are synthesizing relatively large amounts of GAGs, although incorporation of these macromolecules into the extracellular matrix was consistently low.

Animals↗
PubMed1988

Conjunctival oxygen tension monitoring during a controlled phlebotomy.

A decrease in the conjunctival oxygen tension (Pcjo2) and conjunctival index (Pcjo2/Pao2) has been shown to be an early marker of acute blood loss. We sequentially measured Pcjo2, Pcjo2/Pao2, blood pressure, and pulse rate in five healthy adults after controlled phlebotomy of 450 mL and after intravenous fluid repletion. No significant changes occurred in either the Pcjo2 or Pcjo2/Pao2 after phlebotomy or after fluid replacement. We conclude that a blood loss of 450 mL in healthy, euvolemic adults is insufficient to perturb the conjunctival index. The lower limits of sensitivity of changes in Pcjo2 and Pcjo/Pao2 in response to acute blood loss remain to be established.

Adult↗
PubMed1988

Correlation of transconjunctival PO2 with cerebral oxygen delivery during cardiopulmonary resuscitation in dogs.

The relationship between transconjunctival PO2 (PcjO2) and cerebral oxygen delivery (DO2) was examined in dogs during sinus rhythm and CPR with an inflatable vest. Microsphere-determined cerebral blood flow (CBF), DO2, and PcjO2 readings were normal during sinus rhythm. During CPR, with carotid pressure of 82 +/- 11/25 +/- 5 (SEM) mm Hg, cerebral perfusion and DO2 fell by 53% and 57%, respectively, while PcjO2 fell by 87%. After epinephrine administration, carotid pressure increased to 128 +/- 13/48 +/- 9 mm Hg, and CBF and DO2 rose to 130% and 115% of pre-arrest levels, respectively, but PcjO2 readings remained at 11% of control values. Thus, PcjO2 failed to reflect accurately either CBF or DO2 during CPR. In the presence of epinephrine, PcjO2 does not seem to provide an accurate index of the effectiveness of CPR.

Animals↗
PubMed1987

Continuous Fick cardiac output compared to continuous pulmonary artery electromagnetic flow measurement in pigs.

A system for continuous Fick cardiac output measurement (CFCO) is described and compared to continuous electromagnetic pulmonary artery flow (EMCO) and intermittent thermodilution (TDCO) measurements. Oxygen consumption was determined from continuous respiratory gas exchange analysis and arterio-venous oxygen difference from fiberoptic oximetry. A computer calculated cardiac output and other variables every 20 s. Seven pigs were monitored for a total of 10 h, during which cardiac output was manipulated by obstructing venous return or infusing epinephrine. 1748 pairs of EMCO and CFCO values were compared. The best correlation was obtained when CFCO was advanced 20 s with respect to EMCO (R = .89, CFCO = .99 EMCO + .16). TDCO was compared to EMCO during periods of steady state (R = .85, TDCO = .89 EMCO + 1.25, N = 139). TDCO was also compared with simultaneous CFCO (R = .87, TDCO = .89 CFCO + 1.01, N = 251). CFCO is recommended as a reliable standard of continuous cardiac output measurement. It is not a real time measurement; the technique has a time lag of approximately 20 s which is the result of the time constant of the VO2 measurement. Sources for error are discussed with suggestions for improving quality control.

Animals↗
PubMed1986

An evaluation of the P.K. Morgan pocket spirometer.

UNLABELLED: The P. K. Morgan pocket spirometer, which has recently become available in the United States, is small, portable, relatively inexpensive, and measures forced vital capacity (FVC) and the forced exhaled volume in 1 second (FEV1). We conducted this study to evaluate the accuracy of the FVC and FEV1 measurements by the P.K. Morgan spirometer. METHODS: The flow signal used to evaluate the Morgan spirometer was produced by a Vent-Aid TTL Training Test Lung. The flow of air from the test lung was directed in series through the Morgan's volume transducer and into the bell of a 9-L Collins water-sealed spirometer. RESULTS: The difference between Collins mean FVC and Morgan mean FVC was not significant (P = 0.17). The correlation coefficient for the relationship between Collins FVC and Morgan FVC was 0.996. American Thoracic Society (ATS) standards for accuracy were met by 56% of the FVC volumes measured by the Morgan. The difference between Collins mean FEV1 and Morgan mean FEV1 was clinically small but statistically significant (P = 0.01). The correlation coefficient for the relationship between Collins FEV1 and Morgan FEV1 was 0.999. ATS standards for accuracy were met by 87% of the FEV1 volumes measured by the Morgan. CONCLUSION: The overall accuracy of the Morgan spirometer is adequate for bedside screening, but its accuracy is not sufficient to allow it to be used for diagnostic spirometry in place of more accurate pulmonary function equipment.

Equipment and Supplies, Hospital↗
PubMed1986

A portable and inexpensive computer system to interpret arterial blood gases.

The hand-held computer (HHC) allows computer technology to be brought inexpensively to the patient's bedside. In this paper we describe HHC applications software that interprets oxygenation, ventilation, and acid-base status--and also provides a differential diagnosis and makes suggestions for therapy. Although this software was designed to be used in an emergency department, it has equally useful applications elsewhere such as in critical care units. Computerized arterial blood gas interpretation is especially helpful to students and others who infrequently interpret arterial blood gases. The software described here has been enthusiastically accepted by emergency department personnel in our institution.

Blood Gas Analysis↗
PubMed1985

Ventilatory volumes using mouth-to-mouth, mouth-to-mask, and bag-valve-mask techniques.

The volumes delivered to a resuscitation manikin were compared using four ventilatory techniques: mouth-to-mouth, mouth-to-mask, one-person bag-valve-mask, and two-person bag-valve-mask. The effects of experience and sex of the rescuer on the resuscitation volume delivered were also evaluated. The volume delivered using the one-person bag-valve-mask technique was significantly less than that using the other three techniques (P less than 0.001). The experience and sex of the rescuer made no significant difference in the volume delivered using any of the techniques. As compared with the one-person technique, bag-valve-mask ventilatory volume improved significantly when it was performed as a two-person technique. The mean volumes delivered using mouth-to-mouth and mouth-to-mask ventilation were lower than those recommended by the American Heart Association. Emphasis must be placed on ventilation with an adequate volume when these techniques are taught. When mouth-to-mouth and mouth-to-mask ventilation are taught, a spirometer should be used with the manikin so that the rescuer can learn how to estimate an adequate expired volume.

Allied Health Personnel↗
PubMed1984

Use of high-frequency jet ventilation to prevent aspiration in a patient with an uncuffed tracheostomy tube.

We report the use of high-frequency jet ventilation (HFJV) in a patient with an uncuffed tracheostomy tube who had significant pulmonary aspiration of upper-airway secretions. Respiratory secretions decreased during HFJV, indicating that the patient was no longer aspirating. Despite a continuous flow of gas out of the patient's nose and mouth, arterial blood gases remained within acceptable limits. We conclude that HFJV can prevent aspiration and maintain adequate ventilation when used with an uncuffed tracheostomy tube.

Blood Gas Analysis↗