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Biomedical subjects

H Lee

Publications and source records attributed to H Lee.

At least 667 records · Page 37Linked to original sources
PubMed1992

Brain SPECT imaging in progressive aphasia.

Progressive aphasia without dementia is a relatively uncommon neurobehavioral syndrome. The initial presentation of progressive aphasia without cognitive impairment may pose a diagnostic dilemma. The authors report a patient with progressive aphasia. The initial neuro-imaging studies (MRI, CT) were not diagnostically helpful. However, brain SPECT imaging with Tc-99m HMPAO clearly demonstrated a left temporal lobe abnormality. This report discusses the potential clinical usefulness of brain SPECT imaging in the evaluation of neurobehavioral disorders.

Aphasia↗
PubMed1992

Prediction criteria for successful weaning from respiratory support: statistical and connectionist analyses.

OBJECTIVE: To develop predictive criteria for successful weaning of patients from mechanical assistance to ventilation, based on simple clinical tests using discriminant analyses and neural network systems. DESIGN: Retrospective development of predictive criteria and subsequent prospective testing of the same predictive criteria. SETTING: Medical ICU of a 300-bed teaching Veterans Administration Hospital. PATIENTS: Twenty-five ventilator-dependent elderly patients with acute respiratory failure. INTERVENTIONS: Routine measurements of negative inspiratory force, tidal volume, minute ventilation, respiratory rate, vital capacity, and maximum voluntary ventilation, followed by a weaning trial. Success or failure in 21 efforts was analyzed by a linear and quadratic discriminant model and neural network formulas to develop prediction criteria. The criteria developed were tested for predictive power prospectively in nine trials in six patients. RESULTS: The statistical and neural network analyses predicted the success or failure of weaning within 90% to 100% accuracy. CONCLUSION: Use of quadratic discriminant and neural network analyses could be useful in developing accurate predictive criteria for successful weaning based on simple bedside measurements.

Aged↗
PubMed1992

Intensive care treatment of patients with bleeding esophageal varices: results, predictors of mortality, and predictors of the adult respiratory distress syndrome.

OBJECTIVES: To determine the factors predicting mortality from bleeding esophageal varices and to examine the possibility of an association between the development of adult respiratory distress syndrome (ARDS) and the use of ethanolamine oleate as an esophageal variceal sclerosant. DESIGN: Retrospective review. SETTING: ICU in a teaching hospital. PATIENTS: A total of 101 patients with endoscopically confirmed bleeding esophageal varices were admitted on 124 occasions from 1985 to 1990. Mean age was 50 +/- 13.5 (SD) yrs. There were 62 males and 39 females. Using the Child-Pugh classification, 21.8% patients were class A, 38.6% class B, and 39.6% class C. Mean ICU and hospital lengths of stay were 5.4 +/- 5.1 and 19.6 +/- 16.1 days, respectively. Mean Acute Physiology and Chronic Health Evaluation (APACHE II) score on admission was 16.5 +/- 7.6. INTERVENTIONS: Endoscopic variceal sclerotherapy was performed in 99 (79.8%) of 124 ICU admissions in the 101 patients. Esophageal balloon tamponade was performed in 64 (51.6%) and a vasopressin infusion was administered in 47 (37.9%) of the 124 ICU admissions. A variety of factors was studied to find predictors of mortality and the development of ARDS. RESULTS: Forty-eight (48.5%) of the 101 patients died during the hospital stay. Independent predictors of mortality (by stepdown logistic regression) were total volume of ethanolamine oleate injected during sclerotherapy, multiple blood transfusions, Glasgow Coma Scale score, International normalized ratio for prothrombin test, and the presence of circulatory shock on ICU admission. Age, sex, Child-Pugh score, APACHE II score, serum bilirubin, albumin, and creatinine concentrations, use of esophageal balloon tamponade or vasopressin infusion, sepsis, pneumonia, congestive cardiac failure, aspiration, and ARDS were not statistically independent predictors of outcome. There was no difference in the mortality rates for the various causes of liver disease. Pulmonary complications occurred in 44 (43.6%) patients; sepsis occurred in 31 (25%) patients. ARDS developed in 14 patients (11.3% admissions, 13.9% patients). Statistically independent predictors of ARDS were sepsis, low plasma albumin concentration, use of esophageal balloon tamponade, and more than one sclerotherapy session. The volume and type of sclerosant used were not statistically independent predictors. CONCLUSIONS: Outcome is poor for patients with bleeding esophageal varices requiring ICU admission and is related to the severity of liver failure, the degree of blood loss, and failure of therapy to stop the bleeding. The findings do not support an association between the use of the sclerosant ethanolamine and the development of ARDS.

Adult↗
PubMed1992

DNA sequence requirements for generating paused polymerase at the start of hsp70.

RNA polymerase II is transcriptionally engaged but paused approximately 25 nucleotides from the start site of the hsp70 gene of Drosophila melanogaster in uninduced (non-heat-shocked) flies. Here, we identify regions of the hsp70 promoter that are required for formation of this paused polymerase. Various hsp70 promoter sequences are substituted for promoter sequences of a yolk protein gene, yp1, which, in males, is normally not expressed and has no paused polymerase. Run-on assays with nuclei of male transgenic flies are used to measure the level of paused polymerase on the hybrid genes. Sequences that reside upstream of the hsp70 TATA element, when fused upstream of the yp1 TATA element, specify the formation of a paused polymerase on the 5' end of this hybrid gene. Within this region are multiple copies of the GAGA element, which is known to bind a constitutively expressed factor. This element appears to play a role in generating the pause. Also, in the absence of much of this upstream region, hsp70 sequences in the vicinity of the transcriptional start and pause site participate in specifying the pause. Deletions of the pause site reduce the level of paused polymerase but do not lead to constitutive transcription. However, a connection between transcription and pausing is seen. The level of paused polymerase on the various hybrid hsp70-yp1 promoters correlates with the promoter's potential to direct heat-induced transcription.

Animals↗
PubMed1992

Lansoprazole and omeprazole have similar effects on plasma gastrin levels, enterochromaffin-like cells, gastrin cells and somatostatin cells in the rat stomach.

This study compares the effects of lansoprazole and omeprazole on the activation and proliferation of enterochromaffin-like (ECL) cells in the rat stomach. Lansoprazole was given orally once daily for 10 weeks in two doses, 135 and 200 mumol/kg. Omeprazole was given by the same regimen in a dose of 400 mumol/kg, which is equipotent in terms of acid inhibition to the higher lansoprazole dose. Lansoprazole (both doses) as well as omeprazole raised the plasma gastrin levels about 11-fold 2 h after dosing and 8-to 10-fold 24 h after dosing, reflecting complete (2 h) and 70-80% (24 h) reductions of gastric acid secretion. Administration of either drug for 10 weeks increased the weight of the stomach and the oxyntic mucosa. The oxyntic mucosal histidine decarboxylase activity, histamine concentration and ECL cell density were increased to the same extent in the rats given either of the two lansoprazole doses or omeprazole. The numbers of antral gastrin cells were doubled and the numbers of antral somatostatin cells half that in the controls. These results show that long-standing lansoprazole-evoked hypergastrinemia affects the ECL cell similarly to omeprazole, ranitidine and other acid secretion inhibitors.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1992

Enhancement of rabbit cardiac sodium channels by beta-adrenergic stimulation.

Voltage-dependent sodium channels from a variety of tissues are known to be phosphorylated by the cAMP-dependent protein kinase, protein kinase A. However, the functional significance of sodium channel phosphorylation is not clearly understood. Using whole-cell voltage-clamp techniques, we show that sodium currents (INas) in rabbit cardiac myocytes are enhanced by isoproterenol (ISO). This enhancement of INa by ISO 1) is holding potential dependent, 2) can be mimicked by forskolin and dibutyryl cAMP, and 3) is accompanied by an increase in the rate of Na+ channel inactivation. In single-channel, inside-out patch experiments, the catalytic subunit of protein kinase A also enhances INa and increases the rate of inactivation, suggesting that cardiac Na+ channel phosphorylation may be physiologically important. Addition of the protein kinase A inhibitor to the pipette solution in whole-cell experiments blocks the stimulatory effect of forskolin without blocking the effect of ISO, suggesting that ISO also enhances INa through a cAMP-independent pathway. To determine if ISO may stimulate INa through a direct G protein pathway, single channels were recorded in the presence of the Gs-activating GTP analogue, GTP gamma S, and the stimulatory G protein subunit, Gs alpha. Both of these agents enhanced INa without affecting the rate of Na+ channel inactivation. These results suggest that ISO enhances rabbit cardiac INa through a dual (direct and indirect) G protein regulatory pathway.

Animals↗
PubMed1992

Effect of overcooked soybean meal on chicken performance and amino acid availability.

Studies were conducted to evaluate the effect of overcooked soybean meals (SBM) on chick growth and amino acid availability. The SBM were custom-prepared at a commercial processing plant by changing the conditions of a desolventizer-toaster (DT) unit. Six progressively overcooked meals (designated SBM1 to 6 with SBM1 as normal, and SBM6 overcooked) were produced by increasing temperature by up to 50% and extending retention time by up to 75% above normal. The meals measured .05, .03, .01, .09, .00, and .00 delta pH of urease activity; 6.10, 5.01, 4.62, 4.83, 2.32, and 1.78 mg/g SBM of trypsin inhibitor activity; 92, 89, 91, 88, 81, and 81% of protein solubility in .2% KOH; and 46, 43, 41, 40, 23, and 19% of protein solubility in .1 M borate at 40 C, respectively. Glucose content in the hydrolysate of the soluble carbohydrate extract did not differ among the meals, indicating no differences in the degradation of sucrose, raffinose, and stachyose with increasing heat treatment. In a chick growth experiment with a methionine-adequate, low-protein diet, chicks fed SBM1 showed significantly greater weight gain than chicks fed SBM3, 5, or 6. The SBM1, 2, 5, and 6 were chosen for a study of amino acid availability. No differences were observed in amino acid content. There were significant differences in apparent amino acid availability to growing chicks, but not in true amino acid availability by adult roosters among the four meals. The results suggest that the temperature or the retention time of a DT unit may be increased by 50% over the usual operating conditions without reducing amino acid availability from SBM.

Amino Acids↗
PubMed1992

Segmenting the student healthcare market: implications for long-term and preventive healthcare.

This paper presents the findings of a cross-institutional study of health care concerns and activities of 18-25 year old college students. In general, the subjects tended to perceive themselves as quite healthy, and were not highly concerned about health issues. However, the subject group was not homogeneous. Therefore, this paper identifies three different segments of college students--the "Unconcerned" group, the "Worried" group, and the "Physical Image" group--and details their different attitudes, concerns, and behaviors.

Adult↗
PubMed1992

Value of scintigraphic localization of obscure gastrointestinal bleeding.

A total of 51 technetium-99m (99mTc)-labelled autologous red cell (LRC) scans performed on 49 patients for the localization of obscure gastrointestinal bleeding over a 5-year period was reviewed. The sensitivity for LRC scanning was 72.7% with a positive predictive value of 84.2%. Forty patients underwent both LRC scanning and visceral angiography during the same admission; angiography had a sensitivity of 38.9% compared with 66.7% for LRC scanning and the positive predictive values were 77.8% and 85.7%, respectively. Overall, the site of bleeding was located in 22 (45%) of 49 patients, but LRC scanning alone was successful in identifying the lesion in 16 (33%) cases. In patients who continue to bleed to the point of requiring operation, a combination of scintigraphy and angiography will localize a source in 70% of patients.

Aged↗
PubMed1992

Antibody to HIV-1, HTLV-I, and HCV in three populations of rural Haitians.

The seroprevalence of antibodies to HIV-1, HTLV-I, and HCV was evaluated in three populations from northern rural Haiti: 1,727 patients attending the hospital for symptoms suggestive of HIV disease, 228 consecutive surgical patients, and 500 pregnant women were tested. HIV-1 seroprevalence was 6.1 and 4.0% in the last two groups, respectively, and 39.3% in the symptomatic population. Associated symptoms of wasting, cough, and diarrhea and a clinical diagnosis of AIDS were significantly predictive of HIV-1 seropositivity. Antibody to HTLV-I seroprevalence ranged from 2.2-5.3% in pregnant women, surgical patients, and HIV-seronegative symptomatic patients and was similar among the three groups when stratified by age. In contrast, HIV-1 seropositivity and HTLV-I seropositivity were significantly associated. The prevalence of confirmed antibody to HCV was low and not associated with either HIV-1 or HTLV-I seropositivity.

Adolescent↗
PubMed1992

Interaction of rat peritoneal macrophages with homologous sialidase-treated thrombocytes in vitro: biochemical and morphological studies. Detection of N-(O-acetyl)glycoloylneuraminic acid.

Sialidase treatment of rat thrombocytes led to an increased binding of these cells to homologous peritoneal macrophages, but had no significant effect on the rate of phagocytosis during the experimental time. As revealed by electron microscopy, the partially desialylated thrombocytes adhere to macrophages predominantly via a small part of the membrane in a way that the discoidal cells adopt a vertical position with regard to the macrophage surface. One adherent macrophage was able to bind up to 55 sialidase-treated thrombocytes. Maximum binding was already reached after release of 13% of sialic acids. This interaction could be inhibited by free D-galactose and compounds with terminal D-galactose residues. Bound thrombocytes were released from the macrophages by treatment with lactose or EDTA. These experiments suggest that the interaction is mediated by a galactose-specific receptor on the macrophage surface and that galactose on thrombocytes is not recognized if it is masked by terminal sialic acid residues. The total sialic acid amount of the thrombocytes studied was about 70 micrograms sialic acid/10(10) cells being composed of 78% N-glycoloylneuraminic acid, 17% N-acetylneuraminic acid and 5% of the novel sialic acid N-(O-acetyl)glycoloylneuraminic acid, which was identified by mass spectrometry. Sixty-two percent of these sialic acids were susceptible to enzymic hydrolysis with Vibrio cholerae sialidase.

Animals↗
PubMed1992

The emerging role of HTLV-I/II and HIV-1 among intravenous drug users in Detroit.

During 1987-1988, a seroprevalence study of the human immunodeficiency virus (HIV-1) and the human T-cell lymphoma/leukemia virus (HTLV-I/II) was performed among Detroit intravenous drug users unaffiliated with substance abuse programs. Seroprevalence data along with patient demographic information were compared to a similar study performed in 1985-1986. In the earlier study, 12 (12.5%) of 96 individuals tested positive for HIV-1. Of the 74 available negative samples retested in 1987-1988 for retroviruses, 7 (9.5%) tested positive for HTLV-I/II. Thus, the overall retroviral (HIV-1, HTLV-I/II) seropositive rate for 1985-1986 was 22%. In 1987-1988, 11 (15.7%) of 70 individuals tested positive for HIV-1 and 7 (10%) tested positive for HTLV-I/II. Concomitant infection with both viruses was found in 2 (2.9%) of the 70 individuals. Thus, retrovirus seroprevalence in 1987-1988 was 22.9%. In 1987-1988, significant differences between the retroviral-positive group and the retroviral-negative group consisted of intravenous drug use greater than 16 years (P = 0.059) for an odds ratio of 3.80 (CI 1.12-12.89) and sex with female prostitutes (P = 0.029) for an odds ratio of 5.38 (CI 1.38-20.95).

Adult↗
PubMed1991

Ultraviolet nicking of large DNA molecules from pulsed-field gels for southern transfer and hybridization.

Large DNA molecules separated in pulsed-field gels are not efficiently transferred from the gel for Southern hybridization. Various procedures for fragmenting the DNA prior to transfer are in use, but quantitative details that permit reproducible application have not been reported. We have determined the optimum level of energy for uv nicking of large DNA needed to promote efficient Southern transfer and detection by hybridization. To ensure consistent results we have used a uv oven equipped with a detector that measures only 200-400 nm wavelengths, and we report the total energy delivered. Using uv nicking and the transfer techniques described, we can obtain hybridization signals overnight with single-copy DNA probes on Southern blots of large DNA fragments separated by pulsed-field gel electrophoresis.

Blotting, Southern↗
PubMed1991

Declining seroprevalence and transmission of HTLV-I in Japanese families who immigrated to Hawaii.

This study examined the seroprevalence and transmission of human T cell lymphotropic virus type I (HTLV-I) in Japanese families who originated in Okinawa, an area in which HTLV-I is endemic, and who were currently residing in Hawaii, a nonendemic area. Among a cohort of Japanese men whose sera were collected in Hawaii in 1967-1975, those of Okinawan ancestry had an HTLV-I seroprevalence of 11.4%. This study, conducted in 1987-1988, sampled 142 index subjects from this male cohort and tested them along with their wives, children, and spouses of the children for HTLV-I antibodies. Seropositivity in their wives was 11.4% and 41.2% among the seronegative and seropositive index subjects, respectively; seropositivity also increased from 29.4% to 35.3% to 58.8% with the husbands' increasing antibody levels by tertiles. Elevated antibody levels may be a marker for infectivity, which is associated with more efficient sexual transmission of HTLV-I. The age-adjusted odds ratio for the association of seropositivity between husband and wife, however, was four times lower than that reported among native Okinawans. In addition, a substantially low seroprevalence (1.3%) was found among their offspring. The decline in HTLV-I transmission in this migrant population may be due to low infectivity in the parent generation who live in a nonendemic environment, increasing numbers of offspring marrying outside of the Okinawan community, and improved living circumstances.

Aged↗
PubMed1991

Co- and post-translational processing of the hevein preproprotein of latex of the rubber tree (Hevea brasiliensis)

Hevein is a chitin-binding protein of 43 amino acids found in the lutoid body-enriched fraction of rubber tree latex. A hevein cDNA clone (HEV1) (Broekaert, W., Lee, H.-i., Kush, A., Nam, C.-H., and Raikhel, N. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 7633-7637) encodes a putative signal sequence of 17 amino acids followed by a polypeptide of 187 amino acids. Interestingly, this polypeptide has two distinct domains: an amino-terminal domain of 43 amino acids, corresponding to mature hevein, and a carboxyl-terminal domain of 144 amino acids. To investigate the mechanisms involved in processing of the protein encoded by HEV1, three domain-specific antisera were raised against fusion proteins harboring the amino-terminal domain (N domain), carboxyl-terminal domain (C domain), and both domains (NC domain). Translocation experiments using an in vitro translation system show that the first 17-amino acid sequence encoded by the cDNA functions as a signal peptide. Immunoblot analysis of proteins extracted from lutoid bodies demonstrates that a 5-kDa protein comigrated with purified mature hevein and cross-reacted with N domain- and NC domain-specific antibodies. A 14-kDa protein was recognized by C domain- and NC domain-specific antibodies. A 20-kDa protein was cross-reactive with all three antibodies. Microsequencing data further suggest that the 5-kDa (amino-terminal domain) and 14-kDa (carboxyl-terminal domain) proteins are post-translational cleavage products of the 20-kDa polypeptide (both domains) which corresponds to the proprotein encoded by HEV1. In addition, it was found that the amino-terminal domain could provide chitin-binding properties to a fusion protein bearing it either amino terminally or carboxyl terminally.

Antimicrobial Cationic Peptides↗
PubMed1991

Homodimer and heterodimer subunits of human prostate acid phosphatase.

Human prostatic acid phosphatase (PAP) isoenzymes, designated PAP-A and PAP-B, were isolated from human seminal plasma by sequential affinity chromatography on concanavalin A and L(+)-tartrate, a classic inhibitor of PAP. Both the major PAP-A and the minor PAP-B isoenzymes exhibited a similar molecular mass (100 and 105 kDa respectively), multiple pI values (5.05-5.35 and 5.05-5.12), and substrate and inhibitor specificity. Immunological characterization revealed that PAP-B possesses distinct antigenic determinants, in addition to the common sites shared with PAP-A. SDS/PAGE indicated that both isoenzymes are composed of two subunits of 50 kDa each. At high salt concentration, PAP-B dissociated completely into single subunits of 50 kDa, whereas PAP-A remained intact at 100 kDa. PAP-B was resolved by reverse-phase h.p.l.c. into three components, designated alpha, beta and gamma, each of 50 kDa, at a molar ratio of approx. 2:1:1. PAP-A contained a single component of molecular mass 50 kDa. The single component of PAP-A and the alpha component of PAP-B possessed identical amino acid compositions and N-terminal sequences, which were different from those of the beta and gamma components. These results indicate that human PAP contains three isoforms, alpha 2, alpha beta and alpha gamma. PAP-A, the major isoenzyme, is a homodimer consisting of two identical subunits (alpha 2), and PAP-B, the minor isoenzyme, is a mixture of two heterodimers, consisting of non-identical subunits (alpha beta and alpha gamma).

Acid Phosphatase↗