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Biomedical subjects

J J Hwang

Publications and source records attributed to J J Hwang.

At least 163 records · Page 9Linked to original sources
PubMed1991

Comparison of pulmonary tuberculosis in younger and elderly patients.

Pulmonary tuberculosis remains a significant clinical and public health problem in the elderly population. To describe age-related differences in disease manifestations, a comparison of the clinical features, predisposing factors, diagnostic approaches and radiographic findings in cases of pulmonary tuberculosis among 52 young and 62 elderly patients was performed. The elderly patients had a higher number of underlying disease than younger patients (p less than 0.05). Prior to admission, symptoms occurring with equal frequency in both younger and elderly patients included coughing, malaise, and weight loss. Elderly patients had significantly higher incidences of negative reactions to the PPD test (p less than 0.05). Radiographic findings revealed that upper lung field infiltrates were still common in both groups, but the elderly had more severe lung field involvement (two or more lobes affected), and more frequent pleural reactions than younger patients (p less than 0.05). Since there were non-specific clinical features, false negative skin test and complex radiographic manifestations, tuberculosis was frequently not suspected in the differential diagnosis, especially among elderly patients with multiple medical problems. We suggest that physicians need to have a high level of suspicion and awareness of varied manifestations for tuberculosis, especially elderly patients.

Adult↗
PubMed1990

Evaluation of host defense in critically ill patients in medical intensive care unit.

Thirty three patients, 24 male and 9 female, aged from 19 to 90 with an average of 58.8, were admitted to the medical intensive care unit (ICU) from 1988 December to 1989 December. Their host defenses were evaluated. Cell-mediated immunity (CMI) included delayed type skin test (MULTITEST CMI), total lymphocyte count and lymphocyte subpopulations (CD3, CD4 and CD8) were determined. Investigation of humoral immunity (HI) included use of serum levels of immunoglobulins (IgG, IgA and IgM) and complements (C3 and C4). Episodes of nosocomial infection were documented by patients' clinical and laboratory data, including positive culture. The CMI, especially for total lymphocyte count, T lymphocyte count and skin test, was impaired by underlying diabetes mellitus and such associated conditions as malnutrition, steroid administration and surgical procedures. The longer the admission period, the lower was the CMI including total lymphocyte count, CD3 percentage, CD4 percentage and skin test response. The HI was less impaired by underlying conditions and not influenced by admission duration. More infection episodes were found in patients with longer admission duration. In conclusion, the host defense was impaired in patients hospitalized longer in medical ICU, and the combination of compromised immunity and impaired mucocutaneous barriers made them more susceptible to infections.

Adult↗
PubMed1990

Quantitative C-reactive protein in pulmonary infections.

A total of 207 cases were selected to evaluate the diagnostic value of C-reactive protein (CRP) in pulmonary infections. The mean +/- SD of CRP values in various pulmonary infections were as follows: 18.62 +/- 11.34 micrograms/ml for 32 cases of exudative-fibrotic tuberculosis; 15.98 +/- 16.66 micrograms/ml for 15 cases of tuberculous pneumonia; 25.61 +/- 18.96 micrograms/ml for 29 cases of tuberculous effusion; 16.66 +/- 10.18 micrograms/ml for 11 cases of tuberculous cavity; 81.1 +/- 24.9 micrograms/ml for 10 cases of miliary tuberculosis; 36.4 +/- 22.1 micrograms/ml for 19 cases of mycoplasmal pneumonia; 241 +/- 72 micrograms/ml for 38 cases of bacterial pneumonia; 225 +/- 65 micrograms/ml for 30 cases of bacterial pneumonia with effusion; 169 +/- 50 micrograms/ml for 16 cases of lung abscess. The CRP values of other pulmonary infections were as follows: 20.6, 20.8 micrograms/ml for two cases of Strongyloides stercoralis pneumonia; 7.4, 1.6 micrograms/ml for two cases of aspergilloma; 11.2, 12.4, 7.6 micrograms/ml for three cases of Pneumocystis carinii pneumonia. Serial changes in CRP values in 13 cases of well-treated bacterial pneumonia showed that values of CRP decreased to below half of the initial value on the 3rd to 4th day, and returned to about normal value on the 10th to 13th day. The study suggested that: a) various types of infections had different levels of CRP values, b) level of CRP values was determined both by the pathogen and the severity of inflammation, c) serial CRP values in bacterial infection could be used as a guide in treatment.

Adolescent↗
PubMed1990

[Dose-response relationships of propofol in Chinese].

Propofol is a new intravenous anesthetic which possesses the rapid induction and recovery of anesthesia. It has been approved to be used in clinical anesthesia and critical care medicine since 1989. From the dose-response study of propofol, we can get the ED50 and induction dose of propofol and compare those with other anesthetics. Sixty young patients, ASA I-II, both sexes, were allocated into six groups of ten patients. All of patients did not receive premedicants. Groups I-VI were given intravenously over 25 sec 1.0 mg/kg, 1.2 mg/kg, 1.4 mg/kg, 1.6 mg/kg, 1.8 mg/kg and 2.0 mg/kg, respectively. Blood pressure and heart rate were monitored and recorded before and 1 min, 3 min, 5 min after the injection of propofol. Induction of anesthesia by propofol is considered to be successful as a patient closes his eyes and does not response to simple command. As a patient obeys the order to open his eyes, he is judged to emerge from anesthesia. Induction and recovery times were recorded in each successfully-induced patient. Data were analyzed using Litchfield and Wilcoxon, and Student's t tests. The ED50 of propofol was found to be 1.46 mg/kg (95% confidence interval: 1.35 mg/kg to 1.58 mg/kg). Induction and recovery times at 1.0 mg/kg, 1.2 mg/kg, 1.4 mg/kg, 1.6 mg/kg, 1.8 mg/kg and 2.0 mg/kg were 40 sec and 5.6 min, 38 sec and 6.0 min, 38 sec and 6.2 min, 36.8 sec and 6.7 min, 36.3 sec and 7.2 min, 35.5 sec and 7.2 min, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Monoclonal antibodies specific for rat relaxin. IV. Passive immunization with monoclonal antibodies during the antepartum period reduces cervical growth and extensibility, disrupts birth, and reduces pup survival in intact rats.

The purpose of this investigation was to use an approach targeted specifically on endogenous relaxin to determine the influence of antepartum (days 20-22) relaxin on cervical modifications and birth in the rat. To that end, a monoclonal antibody specific for rat relaxin, designated MCA1, was used to neutralize endogenous relaxin in intact pregnant rats. MCA1 or PBS vehicle was administered iv to intact rats daily from days 20-22 of pregnancy. Cervices were removed at 1200 h on day 22. Cervices obtained from MCA1-treated rats were less extensible than cervices obtained from PBS-treated control rats. Furthermore, wet weight, dry weight, water content, and uronate content were lower in cervices obtained from MCA1-treated rats than in cervices from PBS-treated controls. Birth and maternal behavior of MCA1-treated and PBS-treated control rats were observed continuously from 2100 h on day 22 until day 2 postpartum (d2PP). MCA1-treated rats exhibited significantly prolonged durations of litter delivery as well as reduced incidences of live pups on d2PP compared with controls. There were lower incidences of normal maternal behavior observed at birth and on d1PP with MCA1-treated rats than with control rats. In addition, little or no milk was observed in the abdomen of most live pups of MCA1-treated rats on d2PP, whereas abundant milk was observed in the abdomen of all live pups of control rats. The mean live pup weight on d2PP was lower in the litters of MCA1-treated rats than in control litters. The present study indicates that in the rat endogenous relaxin is needed during the antepartum period for normal cervical growth and extensibility, normal litter delivery, and high postpartum pup survival. This work supports the hypothesis that the influence of endogenous relaxin on birth is attributable, at least in part, to its effects on the cervix.

Animals↗
PubMed1989

Diagnostic value of ferritin measurements in patients with pleural effusions.

The diagnostic value of ferritin measurements has been evaluated in 59 patients with pleural effusions (PE). The Mean(+/- standard error [SE]) PE-ferritin level was 1913 +/- 720 ng/ml in 10 patients with nonmalignant nontuberculous (nonTB) exudates (Group I), 594 +/- 110 ng/ml in 14 patients with TB effusions (Group II), 1286 +/- 194 ng/ml in 28 patients with malignant exudates (Group III), and 280 +/- 60 ng/ml in 7 patients with transudates (Group IV). Significant difference was found between Group II and Group III (p less than 0.05). The mean (+/- SE) ratio of PE/serum (PE/S) ferritin in Groups I, II, III, and IV was 3.5 +/- 1.1, 10.5 +/- 5.1, 4.9 +/- 1.0, and 2.0 +/- 0.7, respectively, and it showed no significant difference among Groups I, II, and III. There were good correlations between PE-ferritin and PE-LDH or S-ferritin, but no correlation between PE-ferritin and PE-protein. PE-ferritin revealed a considerable overlap among the exudative groups, and was of no value in the differentiation between malignant and nonmalignant (Group I + II) exudates. In the discrimination between exudates and transudates, the diagnostic accuracy (86%) of PE-ferritin was inferior to those (all 98%) of PE-protein, PE-LDH, PE/S protein ratio, and PE/S LDH ratio. Using PE-ferritin greater than or equal to 500 ng/ml in distinguishing malignant exudates from TB effusions, the sensitivity was 79%, specificity 57% and accuracy 71%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Pneumocystis Carinii pneumonia in an AIDS patient with dramatic response to inadvertent steroid therapy--a case report.

A 28 year-old homosexual man had one month history of intermittent high fever, nonproductive cough and progressive shortness of breath. He not only had immunity deficits, with decrease CD4 cells decreased CD8 cells and inverted CD4/CD8 ratio, but also presented with evidence of human immunodeficiency virus infection (positive ELISA antibody tests and Western blot tests). Chest X-ray showed diffuse pulmonary infiltration. The arterial blood gases revealed hypoxemia. The PaO2 was 69 mmHg. Spirometry showed FVC 2.28 L (45% predicted), FEV1 2.21 L (49% predicted), FEV1/FVC 93%, and MMEF 4.41 L/sec (90% predicted). The configuration of the Flow-Volume loop was consistent with a restrictive ventilatory defect. Transthoracic lung biopsy demonstrated pneumocystis carinii pneumonia (PCP). He had inadvertent steroid therapy and showed some clinical, pulmonary function and chest X-ray improvement before the diagnosis was established. Steroids might be as adjunctive therapy for a short period of time in treatment of PCP associated with acquired immunodeficiency syndrome (AIDS) at respiratory failure.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Determination of possible doses to the gonads or fetus in pregnant patients during radiation therapy.

Some of the women undergoing radiation therapy may be pregnant and the scatter radiation to the fetus and gonads is a matter of great concern. Quantitative measurement of the scatter dose in polystyrene solid phantoms with a Farmer type chamber and effects of shielding blocks under the collimators were studied. The scatter dose outside of the primary beam was found to be decreasing exponentially with increasing distance from the radiation beam edge. When the distance increased from 10 cm to 60 cm, the scatter dose drops from 1-2% to 0.15% for the Co-60 beam and from 1-2% to 0.02% for the 10 MV X-rays. The collimation system was a major source of scatter radiation because the scatter dose could be substantially reduced by placing shielding blocks under the collimators and the scatter dosed varied with field sizes. The lead apron used in diagnostic radiographic procedures reduced the scatter dose by 5-6% only. The scatter dose distribution in the body outside of the radiation field was also analyzed.

Female↗
PubMed1988

Characterization of a doubly mutant derivative of the lambda PRM promoter. Effects of mutations on activation of PRM.

The mutation, prmE37, located at -14 in the PRM promoter of bacteriophage lambda, reduces PRM function dramatically both in vitro and in vivo. In a search for second-site revertants of prmE37, we isolated a double mutant that exhibits a partially restored Prm+ phenotype. The second-site mutation (at -31) is identical to the mutation prmup-1. The activity of the doubly mutant (pseudo-revertant) promoter, prmE37prmup-1, was investigated in vivo using a PRM-lacZ fusion phage and found to be intermediate between that of prmE37 and wild-type PRM. However, the relative strength of the prmE37prmup-1 promoter was greater than expected following superinfection of a lambda lysogen. Since nalidixic acid was found to preferentially inhibit transcription from the doubly mutant promoter under these conditions, we suggest that DNA supercoiling favors activation of this promoter by repressor. In runoff transcription assays in the absence of repressor, the activity of wild-type PRM and the doubly mutant promoter were the same. However, while addition of repressor significantly stimulated wild-type PRM, it had little or no effect on the activity of the doubly mutant promoter. Values of KB, the equilibrium constant for formation of closed complexes, and kf, the rate constant for isomerization of closed to open complexes, were determined in abortive initiation assays, and the product of kfKB was used as a measure of promoter strength. The results of these assays are in agreement with those obtained in runoff transcription assays. In the absence of repressor, values of kfKB for the doubly mutant promoter and wild-type PRM are the same; however, tau obs, the time required for open complex formation, is significantly greater for the double mutant than for wild-type PRM at all RNA polymerase concentrations used for the abortive initiation analysis. In the presence of repressor, the doubly mutant promoter is stronger than the prmE37 promoter, but much weaker than wild-type PRM. This is due to the fact that kf for the doubly mutant promoter is increased 2.5-fold by repressor, but KB is reduced to the same extent. These two effects counteract each other, so that repressor has no net effect on the strength of the prmE37prmup-1 promoter in vitro. In contrast, repressor increases kf for wild-type PRM eightfold and increases overall promoter strength (KBkf) nearly fivefold. In the presence of repressor, the effects of the two mutations, prmE37 and prmup-1, on kf are independent. This observation is discussed in relation to revised models for open complex formation.

Bacteriophage lambda↗
PubMed1988

Interactions between Escherichia coli RNA polymerase and lambda repressor. Mutations in PRM affect repression of PR.

The rightward operator, OR, of bacteriophage lambda is part of a complex regulatory region that includes PRM, the promoter for repressor synthesis by a prophage, the rightward early promoter PR, and three repressor-binding sites, OR1, OR2 and OR3. By binding to OR2, repressor blocks transcription from PR and simultaneously stimulates the formation of open complexes between RNA polymerase and PRM. In this letter, we describe a test of the hypothesis that the interaction between RNA polymerase bound at PRM and repressor bound at OR2 increases the apparent affinity of repressor for OR. One implication of this hypothesis is that the amount of repressor required for repression of PR should be inversely correlated with PRM promoter strength. This is indeed the case. The amount of repressor required for 50% repression of PR is decreased by prmup-1, an "up" mutation of PRM, and is increased by prm- mutations. An unexpected finding is that in addition to their effect on the apparent affinity of repressor for OR, mutations in the -35 region of PRM alter the shape of repressor-titration curves. We propose that these mutations alter the interaction between RNA polymerase bound at PRM and repressor bound at OR2 in such a way that cooperativity in the binding of repressor to OR1 and OR2 is also disrupted.

DNA-Binding Proteins↗
PubMed1988

Isolation of a cDNA for rat brain glutaminase.

A single phage was isolated from a lambda gt11 rat brain cDNA library by screening with antibodies prepared against rat renal glutaminase. Partial proteolysis of the fusion protein produced by a lysogen of the isolated phage generated a series of immunoreactive peptides that co-migrated with those derived from the purified brain glutaminase. The cDNA has a single open reading frame which encodes 326 amino acids that are in frame with beta-galactosidase. A 72-kDa protein, corresponding in size to the precursor of mitochondrial glutaminase, was immunoprecipitated from the translation products of rat renal mRNA that selectively hybridized to the cDNA. A probe made from the glutaminase cDNA detected an mRNA about 6 kb in length. This mRNA was present in rat brain and normal kidney RNA, increased 6-fold in acidotic kidney RNA, but was not detectable in liver RNA.

Amino Acid Sequence↗
PubMed1988

Monoclonal antibodies specific for rat relaxin. III. Passive immunization with monoclonal antibodies throughout the second half of pregnancy reduces cervical growth and extensibility in intact rats.

Relaxin is required for normal delivery in the rat. The mechanism(s) whereby relaxin contributes to rapid and safe delivery of the fetuses, however, has not been established. The purpose of this investigation was to determine if relaxin enables normal delivery by promoting the growth and modifying the tensile properties of the uterine cervix. To that end, a monoclonal antibody specific for rat relaxin, designated MCA1, was used to passively neutralize endogenous relaxin in intact pregnant rats. MCA1 or PBS vehicle was administered iv to rats daily from days 12-22 of pregnancy. Cervices were removed at 1200 h on day 22. Cervices obtained from MCA1-treated rats were much smaller and far less extensible than cervices obtained from control rats. Moreover, cervices from MCA1-treated rats were less able to accommodate stress created by extension than cervices from control rats. Passive neutralization of relaxin had no influence on 1) the weights of other reproductive tissues (uterus, placenta, and ovary), 2) the number of fetuses, and 3) the viability of fetuses. The present study indicates that in the rat endogenous relaxin is required for promoting cervical growth and softening during the second half of pregnancy. This work supports the hypothesis that the influence of endogenous relaxin on birth is attributable, at least in part, to its effects on the cervix.

Animals↗