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Biomedical subjects

C Her

Publications and source records attributed to C Her.

33 records · Page 2Linked to original sources

Predictors of English fluency among Hmong refugees in Minnesota: a longitudinal study.

The objective of this study was to assess factors associated with later acquisition of English language fluency among Hmong refugees in Minnesota. Fluency in a society's lingua franca is a critical skill in psychosocial adaptation and mental health. A longitudinal study design was used, in which premigration and early postmigration factors were related to subsequent English fluency. The first group of 102 Hmong refugees located in Minnesota by the Immigration and Naturalization Service participated, and were interviewed in their homes. Hmong research assistants collected data using a questionnaire format at 1.5 years following resettlement in the U.S. Eight years later, two measures of English language competence were obtained: a self-assessment and an objective measure of English language fluency. Self-assessed fluency and performance on a brief English test showed good correlation. Greater English fluency on both measures was predicted by the following: younger age, male gender, education or vocational training in Laos prior to migration, occupation in Laos requiring literacy, study of English while in Asia, less proximity to other Hmong households in the U.S., any educational involvement in the U.S. (except English as a second language or ESL training), and not receiving welfare. Self-assessment of English fluency appeared to be a valid measure of competence in English. Demographic characteristics, certain premigration experiences, and early postmigration experiences predicted English fluency after 10 years in the U.S. ESL training was not associated with eventual English fluency on either self-assessment or objective testing. Recommendations are made to enhance English fluency, and hence the psychosocial adaptation of refuguees and other immigrants to the U.S.

Adolescent↗

Human estrogen sulfotransferase gene (STE): cloning, structure, and chromosomal localization.

Sulfation is an important pathway in the metabolism of estrogens. We recently cloned a human liver estrogen sulfotransferase (EST) cDNA. We have now determined the structure and chromosomal localization of the EST gene, STE, as a step toward molecular genetic studies of the regulation of EST in humans. STE spans approximately 20 kb and consists of 8 exons, ranging in length from 95 to 181 bp. The locations of most exon-intron splice junctions within STE are identical to those found in a human phenol ST (PST) gene, STM, and in a rat PST gene. In addition, the locations of five STE introns are also conserved in the human dehydroepiandrosterone (DHEA) ST gene, STD. The 5'-flanking region of STE contains one CCAAT and two TATA sequences. The location of one of the TATA box elements is in excellent agreement with the site of transcription initiation as determined by 5'-rapid amplification of cDNA ends. STE was mapped to human chromosome 4q13.1 by fluorescence in situ hybridization. Cloning and structural characterization of STE will now make it possible to study potential molecular genetic mechanisms involved in the regulation of EST in human tissues.

Amino Acid Sequence↗

Human dehydroepiandrosterone sulfotransferase gene: molecular cloning and structural characterization.

Dehydroepiandrosterone sulfotransferase (DHEA ST) catalyzes the sulfate conjugation of DHEA and other steroids. From 20 to 25% of subjects are included in a subgroup with high levels of hepatic DHEA ST activity, raising the possibility that this enzyme activity might be controlled by a genetic polymorphism. To understand the molecular mechanisms involved in regulating levels of DHEA ST activity in human tissue, we cloned the human DHEA ST gene, STD. STD spans at least 17 kb and is composed of 6 exons and 5 introns. The locations of the splice junctions for several of the introns are identical to those present in the rat phenol or aryl ST gene, the only other cytosolic ST gene for which the entire exon/intron structure has been reported, as well as those present in two partially characterized genes for the rat senescence marker protein, genes that are also thought to encode ST enzymes. The 5'-flanking region of the human STD gene does not contain canonical TATA or CCAAT elements, but this region is capable of promoting transcription of a reporter gene in Hep G2 cells. Molecular cloning and structural characterization of the human STD gene will make it possible to study genetic mechanisms involved in the regulation of DHEA ST activity in human tissue.

Amino Acid Sequence↗

Thermolabile phenol sulfotransferase gene (STM): localization to human chromosome 16p11.2.

Thermolabile (TL) phenol sulfotransferase (PST) catalyzes the sulfate conjugation of phenolic monoamine neurotransmitters such as dopamine and serotonin. We recently cloned a cDNA for human liver TL PST and expressed it in COS-1 cells. We now report the chromosomal localization of the human TL PST gene (STM) as well as its partial sequence. DNA from NIGMS Human/Rodent Somatic Cell Hybrid Mapping Panels 1 and 2 was screened by use of the PCR, and the STM gene was mapped to chromosome 16. Regional localization to 16p11.2 was performed by PCR analysis of a high-resolution mouse/human somatic cell hybrid panel that contained defined portions of human chromosome 16.

Amino Acid Sequence↗

Accurate assessment of right ventricular function in acute respiratory failure.

OBJECTIVE: Since right ventricular ejection fraction is highly dependent on afterload, right ventricular ejection fraction may not reflect right ventricular contractile function in acute respiratory failure. Despite a severe reduction in right ventricular ejection fraction, the right ventricle may be able to generate pressure output that is sufficient enough to maintain an adequate distribution of pulmonary perfusion. We tested this hypothesis by assessing the correlation between the right ventricular ejection fraction and the right ventricular end-systolic pressure-volume relationship, and by assessing the correlations between right ventricular ejection fraction and the physiologic deadspace/tidal volume ratio and between the physiologic deadspace/tidal volume ratio and the right ventricular end-systolic pressure-volume relationship. DESIGN: Prospective study. SETTING: University hospital intensive care unit (ICU). PATIENTS: Twenty-one patients with acute respiratory failure. MEASUREMENTS AND MAIN RESULTS: The physiologic deadspace/tidal volume ratio was used as an index of the distribution of pulmonary perfusion. Right ventricular ejection fraction was measured by the thermodilution method. Right ventricular end-diastolic volume index was obtained from the stroke volume index divided by the right ventricular ejection fraction. Right ventricular end-systolic volume index was calculated as the difference between the right ventricular end-diastolic volume index and the stroke volume index. Pulmonary arterial dicrotic notch pressure was used as an estimate of right ventricular end-systolic pressure. Data were collected at baseline and after one or two alterations in preload to define the right ventricular end-systolic pressure-volume relationship. There was no correlation between the right ventricular ejection fraction and the slope of the right ventricular end-systolic pressure-volume relationship line. No correlation was found between the right ventricular ejection fraction and the physiologic deadspace/tidal volume ratio. There was a hyperbolic curvilinear relationship between the physiologic deadspace/tidal volume ratio and the slope of the right ventricular end-systolic pressure-volume relationship line (r2 = .82, p < .0001). When the patients were divided into two groups based on the slope of the right ventricular end-systolic pressure-volume relationship line, the physiologic deadspace/tidal volume ratio was lower in the group with a high slope of the right ventricular end-systolic pressure-volume relationship line (p < .0001). There was no difference in other hemodynamic data between the two groups. CONCLUSIONS: These data suggest that in acute respiratory failure, the right ventricular ejection fraction does not reflect right ventricular performance.

Adolescent↗

Elevated pulmonary artery systolic storage volume associated with improved ventilation-to-perfusion ratios in acute respiratory failure.

The possibility that an elevated pulmonary artery systolic storage volume (PASSV) correlates with improved overall ratios of ventilation-to-perfusion and hence benefits gas exchange in acute respiratory failure was examined. We examined this by assessing the correlation between PASSV and both the physiologic dead space to tidal volume ratio (VD/VT) and intrapulmonary shunt fraction (Qsp/Qt). The VD/VT and Qsp/Qt were used as an index of distribution of ventilation-to-perfusion as well as efficiency of pulmonary gas exchange. Twenty-eight patients suffering from acute respiratory failure were included. All required mechanical ventilation. PASSV was calculated from the pulmonary artery (PA) compliance and mean PA systolic distending pressure. Pulmonary arteriolar pressures were computed by Fourier analysis. PA compliance was derived from the PA time constant and the PA resistance. Storage volume fraction of stroke volume index (PASSV/SVI) was used to compare individual variations. There were inverse linear relationships between PASSV/SVI and VD/VT (r = 0.693, p less than 0.0001), and between PASSV/SVI and Qsp/Qt (r = 0.427, p = 0.012). Also, a direct correlation was found between VD/VT and PA time constant (r = 0.503, p = 0.002). The patients were divided into two groups based on PASSV/SVI to evaluate the effect of other hemodynamic data on PASSV. Comparison of the two groups revealed that VD/VT and Qsp/Qt were lower (p less than 0.0001, and p = 0.018, respectively), PA time constant was higher (p less than 0.001), and right ventricular stroke-work index was higher (p = 0.005) in the group with a high PASSV/SVI. There were no differences in other hemodynamic data between the two groups. These data suggest that an elevated PASSV may indeed benefit gas exchange in acute respiratory failure.

Acute Disease↗

Factor analysis of the Rudie-McGaughran Essential-Reactive questionnaire for VA alcoholic men.

In this study factor analysis was used to estimate the validity of the Rudie-McGaughran Essential-Reactive questionnaire. Answers of VA alcoholic men were tape-recorded and scored using the Rudie and McGaughran criteria. Only 2 factors, economic dependence and gastrointestinal symptoms, were validated using factor analysis. Five of the remaining six factors evaluated dimensions of dependence unique to the Essential alcoholic men.

Activities of Daily Living↗

Combined epidural and general anesthesia for abdominal aortic surgery.

The hypothesis that combined epidural and light general anesthesia for infrarenal abdominal aortic surgery is associated with a more stable intraoperative course and less postoperative morbidity than general anesthesia alone was tested. The authors compared intraoperative hemodynamic variables and postoperative morbidity between a group with combined epidural and general anesthesia (n = 30) and a group with general anesthesia (n = 19). Patients who had combined epidural and general anesthesia were given epidural bupivacaine intraoperatively and epidural morphine postoperatively. After cross-clamping of the aorta, cardiac index and pulmonary capillary wedge pressure did not change in the group with combined epidural and general anesthesia, whereas cardiac index decreased (mean change, 0.30 L/min/m2; P = 0.0006) and pulmonary capillary wedge pressure increased (mean change, 1 mm Hg; P = 0.007) in the group with general anesthesia. After unclamping, cardiac index increased in both groups (mean change, 0.26 L/min/m2, P = 0.002, and 0.30 L/min/m2, P = 0.001, respectively). Postoperatively, the necessity for ventilatory support and the incidence of respiratory failure were lower in the combined epidural and general anesthesia group than in the general anesthesia group (P = 0.0002 and P = 0.018, respectively). In addition, vasodilator therapy was required less frequently in the group with combined epidural and general anesthesia (P = 0.002). Duration of intensive care unit stay was shorter in the combined epidural and general anesthesia group (2.7 days v 3.8 days, P = 0.003). These data indicate that for infrarenal abdominal aortic surgery, combined epidural and general anesthesia is associated with more stable intraoperative hemodynamics and significantly less postoperative morbidity than general anesthesia alone.

Adult↗

Elevated pulmonary artery systolic storage volume associated with redistribution of pulmonary perfusion.

The possibility that an increased pulmonary arterial systolic storage volume (PASSV) correlates with a significant redistribution of pulmonary perfusion was examined in 30 surgical patients. Right ventricular stroke work index (RVSWI) was used as an index of distribution of pulmonary perfusion. The systolic storage volume was calculated from the pulmonary arterial compliance and mean pulmonary arterial distending pressure. Pulmonary arteriolar pressures were computed by Fourier analysis. Pulmonary arterial compliance was derived from the pulmonary arterial time constant and pulmonary arterial resistance. There was a linear relationship between PASSV and RVSWI (r = .81, p less than .001). Also, a direct correlation was found between RVSWI and pulmonary arterial time constant (r = .45, p less than .01). When the patients were divided into three groups according to the severity of pre-existing disease, linear relationships between PASSV and RVSWI were present in all groups, and the slopes were not different among the three groups. The patients were also divided into two groups based on a storage volume fraction of stroke volume index, to evaluate the effect of other hemodynamic data on the PASSV. Comparison of the two groups revealed that pulmonary arterial pressure and pulmonary arterial compliance were significantly higher in the group with a high storage volume fraction (p = .05 and p = .01, respectively). RVSWI and time constant were also significantly different between the groups (p less than .01 and p less than .01, respectively). We conclude that the pressure work generated by the right ventricle improved the distribution of pulmonary perfusion by increasing PASSV.

Capillary Permeability↗

Right ventricular stroke-work. An index of distribution of pulmonary perfusion in acute respiratory failure.

To evaluate the possibility that an elevated right ventricular stroke-work index observed in acute respiratory failure correlates with less dead space ventilation, 20 patients requiring mechanical ventilation were studied. Ratio of physiologic dead space to tidal volume was used as an index of distribution of pulmonary perfusion. An inverse linear relationship was found between right ventricular stroke-work index and dead space ratio (r = -0.74, p less than 0.001). No correlation was present between cardiac index and dead space ratio. To evaluate the effects of other hemodynamic data on the distribution of pulmonary perfusion, the patients were divided into two groups based on a dead space ratio. Comparison of the two groups revealed right ventricular stroke-work index was significantly higher in the low dead space ratio group (p less than 0.001). There were no differences in cardiac index, pulmonary-artery pressure, or right atrial pressures. These data suggest that elevated right ventricular stroke-work index in acute respiratory failure is associated with more even distribution of pulmonary perfusion, and that patients with a high dead space ratio were characterized by right ventricular dysfunction when compared to patients with a low dead space ratio.

Acute Disease↗

Correction for gas compression in mechanical ventilators.

Errors in measurements arising from compression of gases in a mechanical ventilator may be corrected by calculation based on the compressible volume of the ventilator, or by physical separation of expired from compressed gases. Using a Frumin valve to effect this separation, the volume compressed in the Bear I ventilator was found to be 5.15 ml/mm Hg, and its compressible volume to be 3790 ml (range 3760 to 3806 ml). The ratio of uncorrected/corrected tidal volume (termed the correction factor) was 1.229 +/- 0.014. When VD/VT was corrected using this factor and compared with that obtained by calculating VD/VT using PECO2 measurements in expired air collected from the Frumin valve, the difference between the two was not significant. It is concluded that the use of the Frumin valve is a practical method for determining the true dead space-to-tidal volume ratios and that the application of the correction factor is also reliable.

Airway Resistance↗