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Biomedical subjects

J C Jackson

Publications and source records attributed to J C Jackson.

At least 37 records · Page 2Linked to original sources
PubMed1997

Hepatitis B among the Khmer. Issues of translation and concepts of illness.

OBJECTIVE: To assess the comprehensibility of hepatitis B translations for Cambodian refugees, to identify Cambodian illnesses that include the symptoms of hepatitis, and to combine these observations with critical theoretical perspectives of language to reflect on the challenges of medical translations generally. DESIGN: Open-ended, semistructured interviews, and participant-observation of a refugee community in Seattle, Washington. SETTING: Homes of Cambodian residents of inner-city neighborhoods. PARTICIPANTS: Thirty-four adult Cambodian refugees who had each been educated about hepatitis B through public health outreach. RESULTS: Medical interpreters translated hepatitis B as rauk tlaam, literally "liver disease." Unfortunately, while everyone knew of the liver (tlaam), rauk tlaam was a meaningless term to 28 (82%) of 34 respondents and conveyed none of the chronicity and communicability intended by refugee health workers for 34 (100%) of the respondents. In contrast, all respondents knew illnesses named after symptom complexes that include the symptoms of acute and chronic hepatitis, but do not refer to diseased organs. The Cambodian words chosen to translate hepatitis B reflect the medical thinking and medical authority that can unintentionally overwhelm attempts at meaningful communication with non-English-speaking patients. CONCLUSIONS: To improve comprehension of hepatitis B translations for the Khmer, translators must choose between medical terminology focused on the liver and Khmer terminology which identifies recognizable experiences, but represents important Khmer health concepts. A critical linguistic view of this situation suggests that for these translations to be meaningful clinicians and health educators must first analyze and then monitor the contextual significance of medical language. In cross-cultural settings, this means a partnership with medical interpreters to pay close attention to the experience of illness and social context of the translation.

Adolescent↗
PubMed1997

High-frequency oscillatory ventilation with partial liquid ventilation in a model of acute respiratory failure.

OBJECTIVE: To determine whether there is an improvement in oxygenation when partial liquid ventilation and high-frequency oscillatory ventilation are combined in the treatment of acute lung injury, compared with high-frequency oscillatory ventilation alone. DESIGN: Controlled animal trial. SETTING: Research laboratory in a university setting. SUBJECTS: Ten 3-kg piglets. INTERVENTIONS: Anesthetized piglets underwent high-frequency oscillatory ventilation, with mean airway pressure of 20 cm H2O, before induction of acute lung injury with repeated saline lavage. When PaO2 values were < 100 torr (< 13.3 kPa), five animals were randomized to receive escalating doses (3, 15, and 30 mL/kg) of perflubron at 60-min intervals. The other five animals remained on high-frequency oscillatory ventilation only. Sham dosing was performed at 60-min intervals in these animals. Arterial blood gases were obtained in both groups at baseline, after injury, and after perflubron and sham doses. MEASUREMENTS AND MAIN RESULTS: Statistically significant improvements in oxygenation were demonstrated in animals that received 3 mL/kg of perflubron with high-frequency oscillatory ventilation compared with animals receiving high-frequency oscillatory ventilation alone (253 +/- 161 vs. 90 +/- 30 torr [33.65 +/- 21.46 vs. 12.0 +/- 4.0 kPa], p < .05). Improvements in oxygenation with additional administration of perflubron were not greater than the improvements seen in the high-frequency oscillatory ventilation-only group. PaCO2 and pH were similar in both groups at all times. No hemodynamic compromise occurred in either group of animals. CONCLUSIONS: The combination of low-dose perflubron with high-frequency oscillatory ventilation leads to more rapid improvement in arterial oxygenation than high-frequency oscillatory ventilation alone, in a piglet model of acute lung injury. Although the group receiving high-frequency oscillatory ventilation alone eventually achieved PaO2 values that were equivalent to the group receiving high-frequency ventilation and perflubron, the combination of perflubron with high-frequency oscillatory ventilation may permit effective oxygenation and ventilation at lower mean airway pressures by facilitating alveolar expansion and decreasing intrapulmonary shunt.

Analysis of Variance↗
PubMed1997

Shunt and ventilation-perfusion distribution during partial liquid ventilation in healthy piglets.

Replacing gas in the lung with perfluorocarbon fluids (PFC) and periodically ventilating with a gas [partial liquid ventilation (PLV)] has been shown to improve oxygenation in models of respiratory distress syndrome. We hypothesized that the addition of PFC to healthy lungs would result in shunt, diffusion impairment, and increased ventilation-perfusion (VA/Q) heterogeneity. Previously, Mates et al. showed that O2 shunt and arterial-alveolar CO2 difference increased linearly with dose in piglets given graded intratracheal doses of PFC (10, 20, and 30 ml/kg followed by mechanical ventilation with 100% O2) (E.A. Mates, J. C. Jackson, J. Hildebrandt, W. E. Truog, T. A. Standaert, and M. P. Hlastala. In: Oxygen Transport to Tissue XVI, 1994, p. 427-435). Here we report VA/Q distribution in the same animals, showing a 50% increase in VA/Q heterogeneity during PLV independent of PFC dose. Ventilation heterogeneity was the major factor in this increase, and there was no significant change in dead space ventilation. We also report on five animals given a single 20 ml/kg dose of PFC and followed for 3 h. They showed an increase in shunt during PLV but no change in arterial-alveolar CO2 difference.

Animals↗
PubMed1997

Adverse events associated with exchange transfusion in healthy and ill newborns.

OBJECTIVE: To determine the incidence of adverse events attributable to exchange transfusion during the past 15 years and compare the incidence of severe complications between healthy and ill infants. DESIGN: Medical records for the past 15 years from two teaching hospitals with neonatal intensive care units were reviewed. Those newborns who underwent exchange transfusions were classified as healthy or ill. Adverse events were analyzed to determine whether they were attributable to the procedure. RESULTS: Of the 106 patients who underwent exchange transfusion, 81 were healthy and had no medical problems other than jaundice. The remaining 25 patients were classified as ill and had medical problems ranging from mild to severe. At least 2 (2%) of the 106 patients died of complications probably attributable to exchange transfusion. None of the 81 healthy infants died, but 1 had severe necrotizing enterocolitis requiring surgery. Of the 25 ill infants, at least 3 (12%) experienced severe complications (including 2 deaths) probably attributable to exchange transfusion. Serious complications from the most common adverse events, hypocalcemia and thrombocytopenia, were limited to the group of infants already ill with other medical problems. CONCLUSIONS: Because of the significantly greater rate of severe complications in ill infants, exchange transfusion should be delayed until the risk of bilirubin encephalopathy is as high as the risks of severe complications from the procedure itself (12%). These results do not support recommendations to use lower exchange levels in ill infants compared with healthy infants.

Bacteremia↗
PubMed1996

Partial liquid ventilation with perflubron in premature infants with severe respiratory distress syndrome. The LiquiVent Study Group.

BACKGROUND: The intratracheal administration of a perfluorocarbon liquid during continuous positive-pressure ventilation (partial liquid ventilation) improves lung function in animals with surfactant deficiency. Whether partial liquid ventilation is effective in the treatment of infants with severe respiratory distress syndrome is not known. METHODS: We studied the efficacy of partial liquid ventilation with perflubron in 13 premature infants with severe respiratory distress syndrome in whom conventional treatment, including surfactant therapy, had failed. Partial liquid ventilation was initiated by instilling perflubron during conventional mechanical ventilation to a volume approximating the functional residual capacity. Infants were considered to have completed the study if they received partial liquid ventilation for at least 24 hours. RESULTS: Ten infants received partial liquid ventilation for 24 to 76 hours. In the other three infants, partial liquid ventilation was discontinued within four hours in favor of high-frequency ventilation, which was not permitted by the protocol, and the data from these infants were excluded from the analysis. Within one hour after the instillation of perflubron, the arterial oxygen tension increased by 138 percent and the dynamic compliance increased by 61 percent; the mean (+/- SD) oxygenation index was reduced from 49 +/- 60 to 17 +/- 16. Chest radiographs showed symmetric filling, with patchy clearing during the return from partial liquid to gas ventilation. There were no adverse events clearly attributable to partial liquid ventilation. Infants were weaned from partial liquid to gas ventilation without complications. Eight infants survived to 36 weeks' corrected gestational age. CONCLUSIONS: Partial liquid ventilation leads to clinical improvement and survival in some infants with severe respiratory distress syndrome who are not predicted to survive.

Fluorocarbons↗
PubMed1996

The yeast UME6 gene is required for both negative and positive transcriptional regulation of phospholipid biosynthetic gene expression.

In Saccharomyces cerevisiae, regulation of the phospholipid biosynthetic genes, INO1, CHO1, CHO2 and OPI3, is known to occur at the level of transcript abundance. Derepression in response to inositol deprivation requires the INO2 and INO4 regulatory genes. Repression in response to inositol supplementation requires the OPI1 regulatory gene. Here, we examined the role of the UME6 global negative regulatory gene in expression of the phospholipid biosynthetic genes. These studies were stimulated by the finding that the INO1 promoter included a UME6 cognate cis-acting regulatory sequence (URS1). We found that the UME6 negative regulatory gene was involved in regulation of phospholipid biosynthetic gene expression through two distinct regulatory pathways. One pathway was the direct repression of INO1 expression through the URS1 element. Surprisingly, the UME6 gene was also required for derepression of CHO1, CHO2 and OPI3 gene expression. Consistent with this observation, the UME6 gene was required for wild-type levels of expression of the INO2 positive regulatory gene. Therefore, the UME6 gene has both a negative and a positive role in regulating phospholipid biosynthesis.

Base Sequence↗
PubMed1996

Effects of exogenous surfactant on lung pressure-volume characteristics during liquid ventilation.

Total liquid ventilation (LV) lowers airway pressures and potentially reduces barotrauma in models of hyaline membrane disease. LV eliminates surface tension by eliminating the air-perfluorochemicals (PFC) interface but does not eliminate interfacial tension (IT) at the lung/PFC interface. We hypothesized that pretreatment with exogenous surfactant before LV would shift the overall pressure-volume (PV) curve to the left, compared with LV without surfactant. Sequential quasi-static PV curves were obtained in 10 excised lungs (saline, air, PFC), with one-half randomized to exogenous surfactant replacement before LV. Analysis revealed that maximal inflation pressures were reduced during LV compared with baseline air curves. Addition of exogenous surfactant to LV further reduced maximal inflation pressures. A novel approach was used to transform these PV curves to estimates of in situ IT-volume curves. Estimated maximal IT at 20 ml/kg in preterm lamb lungs on air inflation after surfactant was 51 mN/m, compared with 40 mN/m for LV alone and with 27 mN/m for the combination of surfactant and LV. We conclude that the IT-reducing properties of the PFC studied (perflubron) can be augmented through the use of exogenous surfactant.

Animals↗
PubMed1995

A cDNA from Schizosaccharomyces pombe encoding a putative enolase.

Here we report the isolation of an enolase (Eno)-encoding cDNA clone from Schizosaccharomyces pombe. The deduced amino acid (aa) sequence of the 1.4-kb cDNA shares identifies with a number of Eno from Escherichia coli to humans. The highest degree of similarity is to the known Eno from Saccharomyces cerevisiae and an Eno from Candida albicans. Northern blot analysis identified a single transcript of approx. 1.4 kb, which was most abundant when cells were grown in media with glucose as the carbon source, as opposed to glycerol/lactate or ethanol.

Amino Acid Sequence↗
PubMed1995

Physical map locations of the phospholipid biosynthetic structural and regulatory genes of Saccharomyces cerevisiae.

Here we report the physical map locations of five genes required for phospholipid biosynthesis in Saccharomyces cerevisiae. These include four structural genes (INO1, CHO2, OPI3 and PIS1) and one global negative regulatory gene (UME6). Collectively, this information completes the mapping of all phospholipid biosynthetic structural and regulatory genes identified to date.

Chromosome Mapping↗
PubMed1995

"Strong medicine": Cambodian views of medicine and medical compliance.

OBJECTIVE: To identify important determinants of noncompliance among Cambodian refugees. DESIGN: Open-ended interviews. SETTING: University-affiliated ambulatory care clinic in an inner-city hospital. PARTICIPANTS: Thirty adult Cambodian refugees (15 men and 15 women) who were regular utilizers of a refugee clinic. MEASUREMENTS AND MAIN RESULTS: Sixty-seven percent of the participants described being noncompliant with at least one of their medications. Four common causes of noncompliance were identified: 1) misunderstanding the intent of the medication; 2) side effects; 3) concern about the effect of medication on "internal strength"; and 4) Cambodian ideas about pharmacokinetics. CONCLUSIONS: Noncompliance was commonly reported by the Cambodian respondents. Noncompliance was both intentional and unintentional; the unintended noncompliance derived from patients' attempting to comply with therapy according to Cambodian ideas about the body and Western medication. This article suggests clinical approaches to enhance compliance with prescribed regimens among recent Cambodian immigrants and refugees.

Adult↗
PubMed1995

Outcome of infants weighing less than 800 grams at birth: 15 years' experience.

OBJECTIVE: Mortality and neurodevelopmental morbidity among infants weighing less than 800 g at birth are compared in three separate studies from the same intensive care nursery during an almost 15-year period. METHODS: The survival and neurodevelopmental outcome of 210 infants with birth weights less than 800 g admitted to the University of Washington neonatal intensive care unit between 1986 and 1990 are compared with those of two previous cohorts (1977 through 1980 and 1983 through 1985) of extremely low birth weight (ELBW) infants from the same nursery. RESULTS: Annual admissions of these ELBW infants nearly doubled from 1977 to 1990, whereas nursery survival rose from 20% between 1977 and 1980, to 36% between 1983 and 1985, to 49% in this current study of births between 1986 and 1990. The greatest increase in survival among the three studies occurred among infants with birth weights less than 700 g. Female survival was 20% higher than male survival in each of the time periods. The prevalence of major neurosensory impairments did not differ significantly among the three study groups (19%, 21%, and 22% respectively); male survivors were more commonly affected across time periods. There were no differences in mean cognitive test scores between the current 1986 through 1990 birth cohort (94) and the two previous cohorts (1977 through 1980, 98; 1983 through 1985, 89). CONCLUSIONS: The experience of our center with these ELBW infants over time seems reassuring to the extent that progressive increases in nursery survival have not resulted in increased neurodevelopmental morbidity.

Central Nervous System Diseases↗
PubMed1994

The social significance of routine health behavior in Tamang daily life.

Programs to promote behavioral change among non-Western people sometimes emphasize individual cognitive processes at the expense of social practices. While health beliefs are important, it is equally important to understand the language and the pattern of relationships that affect routine health behaviors. In rural central Nepal we conducted a health survey of 265 Tamang people, followed by a series of 22 in-depth interviews focused on diarrhea and related illnesses. This paper describes the nomenclature used and automatic health behaviors enacted, in response to diarrheal illnesses in Tamang villages. We draw on the work of Anthony Giddens to show that routine health behavior is embedded in specific social relationships that in turn help to structure many aspects of Tamang daily life. We discuss the significance of routine Tamang health behavior in light of oral rehydration therapy programs.

Adult↗
PubMed1994

Reduction in lung injury after combined surfactant and high-frequency ventilation.

Previous studies demonstrated that high-frequency oscillatory ventilation (HFOV) begun at birth limits the development of alveolar proteinaceous edema in premature monkeys at risk for hyaline membrane disease (HMD). We hypothesized that exogenous surfactant combined with HFOV would lead to even further reductions in edema. Twenty Macaca nemestrina monkeys were delivered at 134 d gestation (term = 168 d) and treated with either HFOV or conventional mechanical ventilation (CMV) from the first breath; modified bovine surfactant (Survanta [beractant]) was introduced into the trachea over the first few minutes of life. These animals were compared with 20 animals treated with either CMV or HFOV but without surfactant. At 6 h the lung was rapidly frozen in situ during inflation for determination of the volume fraction of alveolar edema. The combined use of surfactant and HFOV from the first breath reduced alveolar proteinaceous edema (3 +/- 1%; mean +/- SEM) from that seen with CMV alone (27 +/- 3%, p < 0.0001), CMV after surfactant (21 +/- 3%, p < 0.0001), and HFOV alone (13 +/- 3%, p < 0.015). We conclude that the use of surfactant with HFOV after premature birth is superior to either surfactant or HFOV alone in reducing lung injury during the first few hours of life. We speculate that this reduction in lung injury may reduce the incidence or severity of bronchopulmonary dysplasia.

Animals↗
PubMed1994

Changes in hyaluronan deposition during early respiratory distress syndrome in premature monkeys.

Increased deposition of hyaluronan (HA) is part of the early response to fibrogenic stimulus in the lung exposed to bleomycin injury and has been associated with increased lung water in adult animals. Early respiratory distress syndrome (RDS) in premature infants is characterized by increased lung water, and late sequelae include fibrosis or bronchopulmonary dysplasia. We hypothesized that increased HA in the alveolar interstitium would be associated with increasingly severe RDS in prematurely delivered monkeys and that modes of therapy that affect severity of disease such as treatment with high-frequency oscillatory ventilation or exogenous surfactant would decrease this response. Thirty-four Macaca nemestrina monkeys were delivered at 134 +/- 1 d (term = 168 d) and randomized to high-frequency oscillatory ventilation or conventional mechanical ventilation from birth. Sixteen of these animals received surfactant. At 6 h of age, the right lower lung was frozen in situ during inflation to 30 cm H2O (approximately 2940 Pa) and then dehydrated and processed for microscopy. The presence and severity of RDS were evaluated by clinical and morphologic criteria. HA concentrations in lung extracts increased with progressively severe RDS (p = 0.0003). Treatment with high-frequency oscillatory ventilation decreased the lung injury score (1.69 +/- 0.7 compared with 2.5 +/- 0.9, p = 0.05), but changes in lung HA concentration did not reach significance (37.9 +/- 22.7 compared with 44.8 +/- 22.6). Surfactant treatment decreased lung HA concentration (29.6 +/- 19.0 micrograms/wet lung) compared with non-surfactant-treated animals (54.7 +/- 20.2 micrograms/g wet lung, p = 0.0009).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Full-tidal liquid ventilation with perfluorocarbon for prevention of lung injury in newborn non-human primates.

Hyaline membrane disease (HMD), the most common life-threatening respiratory disorder of newborns, is associated with lung injury manifested by alveolar proteinaceous edema. The cause of the disease is thought to be elevated alveolar surface tension due to surfactant deficiency at birth. Treatment with exogenous surfactant may be unsuccessful due to problems in distribution of the surfactant, or inhibition of the surfactant by alveolar proteinaceous edema. Liquid ventilation with oxygen-saturated perfluorocarbon liquid has been proposed as a method to eliminate alveolar surface tension; little is known about the interfacial tension between perfluorocarbon liquids and the lung lining layer. Premature and term newborn monkeys were treated from birth with a pressure-limited, time-cycled liquid ventilator using oxygenated perfluorocarbon liquids (APF-145 and perflubron). Adequate gas exchange was achieved, and pilot experiments suggest long-term survival without adverse sequelae. Although many questions remain, liquid ventilation is a promising tool for the prevention and treatment of lung injury in newborns.

Animals↗