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Biomedical subjects

Q He

Publications and source records attributed to Q He.

At least 127 records · Page 7Linked to original sources
PubMed1999

Enterobacterial infection modulates major histocompatibility complex class I expression on mononuclear cells.

Major histocompatibility complex (MHC) class I expression is reduced in several viral infections, but it is not known whether the same happens during infections caused by intracellular enterobacteria. In this study, the expression of MHC class I antigens on peripheral blood mononuclear cells (PBMC) from 16 patients with Salmonella, Yersinia, or Klebsiella infection was investigated. During or after the acute infection, the expression of MHC class I antigens was markedly decreased in eight patients, all with genotype HLA-B27, and six out of eight with reactive arthritis (ReA). A significant decrease of monomorphic MHC class I was found in three patients, of HLA-B27 in eight (P<0.05) and of HLA-A2 in two. However, patients negative for the HLA-B27 genotype, or healthy HLA-B27-positive individuals, did not have a significant decrease of MHC class I antigens. During the decreased expression on the cell surface, intracellular retention of MHC class I antigens was observed, whereas HLA-B27 mRNA levels did not vary significantly. This is the first evidence that enterobacterial infection may down-regulate expression of MHC class I molecules in vivo and that down-regulation is predominant in patients with the HLA-B27 genotype.

Adolescent↗
PubMed1999

Expression of a higher plant light-harvesting chlorophyll a/b-binding protein in Synechocystis sp. PCC 6803.

A chimeric lhcb gene, coding for Lhcb, a higher plant chlorophyll a/b-binding light-harvesting complex of photosystem II (LHCII), was constructed using the Synechocystis sp. PCC 6803 psbA3 promoter and a modified lhcb gene from pea. This construct drives synthesis of full-length, mature Lhcb under the control of the strong psbA3 promoter that usually drives expression of the D1 protein of photosystem II. This chimeric gene was transformed into a photosystem I-less/chlL(-) Synechocystis sp. PCC 6803 strain that is unable to synthesize chlorophyll in darkness. In the resulting strain, a high level of lhcb transcript was detected and transcript accumulation was enhanced by addition of exogenous Zn-chlorophyllide b. The chimeric lhcb gene was translated to produce full-length Lhcb as demonstrated by pulse-labeling: a new radioactively labeled band of a size corresponding to full-length Lhcb was visible on autoradiograms. Using Triton X-114 phase fractionation, this labeled protein band was found to partition to the phase containing integral membrane proteins, indicating that the pulse-labeled Lhcb is readily integrated into the membrane. However, Lhcb was rapidly degraded and did not accumulate in thylakoid membranes to levels that were detectable other than by pulse labeling. Upon immunological detection with LHCII antibodies, a small protein (approximately 8 kDa) was found specifically in the lhcb-containing mutant. We interpret this protein to be a degradation product of the full-length Lhcb. This fragment was stabilized by supplementing cells with xanthophylls, which incorporated into thylakoid membranes only in the mutant carrying lhcb. The lutein/chlorophyll ratio of thylakoids of this mutant was about 1 : 10. These results indicate that in this cyanobacterial system Lhcb is synthesized, integrated into the membrane, and then degraded to a approximately 8 kDa fragment that is stabilized by pigment binding and does not require the presence of chlorophyll b.

Chlorophyll↗
PubMed1999

Cell-mediated immune responses to antigens of Bordetella pertussis and protection against pertussis in school children.

BACKGROUND: Increasing evidence suggests that cell-mediated immunity (CMI) is involved in immune response against Bordetella pertussis. However, there are practically no studies evaluating the significance of pertussis-specific CMI in relation to protection against clinical pertussis. METHODS: An outbreak of pertussis was studied prospectively in 13-year-old pupils in a rural school. B. pertussis infection was diagnosed by culture, microagglutination and enzyme immunoassay serology with the use of pertussis toxin, filamentous hemagglutinin and pertactin as antigens. Pertussis-specific CMI responses were assessed by in vitro proliferation assay of peripheral blood mononuclear cells. RESULTS: At the initial sampling 7 of 22 children had symptoms suggestive of pertussis and 15 were asymptomatic. Of the latter 3 remained healthy, 8 were later confirmed to have had asymptomatic infection, 3 developed laboratory-confirmed pertussis and 1 developed cough without laboratory evidence of pertussis. Initial in vitro proliferations of peripheral blood mononuclear cells induced by pertussis toxin, filamentous hemagglutinin and/or pertactin were positive in all 3 healthy children, in 6 of 8 children who had asymptomatic infection, but in none of the 3 children who later developed pertussis. Although some children who remained healthy had high values of antibodies, no clear association was found between initial serum antibody values and clinical outcome. CONCLUSIONS: These preliminary data suggest that CMI may have an important role in protection against clinical pertussis but do not exclude a role for antibodies. Furthermore the results stress a multifactorial nature of the immune protection against B. pertussis.

Adolescent↗
PubMed1999

Outcomes of Bordetella infections in vaccinated children: effects of bacterial number in the nasopharynx and patient age.

Five outbreaks of infection (three pertussis, one parapertussis, and one mixed) in schools were studied prospectively. Nasopharyngeal swabs were obtained from a total of 697 children for culture of Bordetella organisms. Of 50 vaccinated children with culture-confirmed Bordetella infections (29 with pertussis and 21 parapertussis), 40 were symptomatic and 10 remained symptom-free. Smaller numbers of colonies were recovered from the nasopharyngeal swabs of the asymptomatic children than from those of the symptomatic children. Older children had longer durations of illness than younger ones. Our results indicate that during outbreaks children who do not develop disease may have small amounts of Bordetella organisms in their nasopharynges and/or better immune defenses against the disease.

Adolescent↗
PubMed1999

Reactive nitrogen and oxygen species ameliorate experimental cryptosporidiosis in the neonatal BALB/c mouse model.

Four-day-old BALB/c mice were infected by the oral administration of 50,000 Cryptosporidium parvum oocysts, and the resulting infection was scored histologically and by counting colonic oocysts. Infection occurred in the ileum and proximal colon (but not duodenum and jejunum), peaked on days 14 to 18, and was cleared between days 24 and 30. Nitric oxide (NO) appeared to play a protective role in this model as evidenced by the facts that plasma nitrite and nitrate levels increased during the period of peak parasitosis; immunohistochemically detected inducible nitric oxide synthase (iNOS) was increased in the ileum and colon enterocytes of infected animals; the NOS inhibitor L-N-iminoethyl lysine or N-nitro-L-arginine methyl ester (L-NAME) decreased the elevated plasma nitrite and nitrate levels while exacerbating the infection and increasing oocyst shedding; administration of a NO donor, S-nitroso-N-penicillamine, reduced oocyst and infection scores; and neonatal iNOS knockout mice exhibited a slightly longer infection than control animals. The oral administration of oocysts to L-NAME-treated BALB/c mice, but not control animals, between 24 and 40 days old resulted in the fecal excretion of oocysts 1 week later. Administration of the antioxidant ascorbic acid also exacerbated the C. parvum infection, suggesting a protective role for reactive nitrogen and/or reactive oxygen compounds, while administration of the superoxide scavenger superoxide dismutase exacerbated the infection. Taken together these data suggest that both reactive nitrogen and reactive oxygen species play protective roles in experimental cryptosporidiosis.

Animals↗
PubMed1999

Variation in the Bordetella pertussis virulence factors pertussis toxin and pertactin in vaccine strains and clinical isolates in Finland.

There is evidence that pertussis is reemerging in vaccinated populations. We have proposed, and provided evidence for, one explanation for this phenomenon in The Netherlands: antigenic divergence between vaccine strains and circulating strains. Finland has a pertussis vaccination history very similar to that of The Netherlands, and yet there is no evidence for an increase in the incidence of pertussis to the extent that it was observed in The Netherlands. A comparison of the Bordetella pertussis strains circulating in the two countries may shed light on the differences in pertussis epidemiology. Here we investigated whether temporal changes had occurred in pertussis toxin and pertactin types produced by the Finnish B. pertussis population. We show that strains isolated before 1964 produced the same pertussis toxin and pertactin variants as the vaccine strains. However, these vaccine types were replaced in later years, and in the 1990s most strains were distinct from the vaccine strains with respect to the two proteins. These trends are similar to those found in the Dutch B. pertussis population. An interesting difference between the contemporary Finnish and Dutch B. pertussis populations was found in the frequencies of pertactin variants, possibly explaining the distinct epidemiology of pertussis in the two countries.

Amino Acid Sequence↗
PubMed1999

Human monocytic U937 cells kill Salmonella in vitro by NO-independent mechanisms.

Nitric oxide (NO) has a central role in host defense against intracellular microbes. HLA-B27 has been shown to directly modulate host-microbe interaction in vitro, leading to the impaired elimination of Salmonella in human monocytic U937 cells. Here, we studied whether impaired elimination of Salmonella would result from differences in NO production between HLA-B27- and HLA-A2-transfected U937 cells. Both human monocytic transfectants produced NO equally well and killed Salmonella via NO-independent mechanisms.

HLA-A2 Antigen↗
PubMed1999

Interleukin-1beta regulation of the human brain natriuretic peptide promoter involves Ras-, Rac-, and p38 kinase-dependent pathways in cardiac myocytes.

Because both the brain natriuretic peptide (BNP) gene and the cytokine interleukin-1beta (IL-1beta) are induced in the infarcted myocardium, localized production of IL-1beta may regulate the BNP gene. We tested whether (1) IL-1beta regulates the human BNP promoter, (2) cis elements in the proximal promoter respond to IL-1beta, and (3) mitogen-activated protein kinase (MAPK) signaling pathways [p42/44, c-jun (JNK) and p38 kinase] are involved. We transferred the hBNP promoter coupled to a luciferase reporter gene or constructs with mutations in the proximal promoter GATA and M-CAT elements into neonatal rat ventricular myocytes and treated the cells with IL-1beta for 24 hours. IL-1beta-stimulated hBNP luciferase activity was eliminated by pretreatment with the transcription inhibitor actinomycin D. Both the p38 kinase inhibitor SB205380 (SB) and cotransfection of a dominant-negative mutant of p38 kinase reduced IL-1beta stimulation of the hBNP promoter. Dominant-negative mutants of Ras and Rac inhibited IL-1beta-stimulated hBNP luciferase activity by 64% and 90%, respectively. Constitutively active forms of Rac and MKK6, the immediate upstream activator of p38, were stimulatory; however, only the effect of MKK6 was inhibited by SB. Neither the p42/44 nor the JNK pathway was involved in the action of IL-1beta. Both IL-1beta and MKK6 activation of the hBNP promoter were partially reduced when the promoter contained a mutated M-CAT element. In summary, (1) IL-1beta is a transcriptional activator of the hBNP promoter; (2) IL-1beta acts through a Ras-dependent pathway not coupled to activation of p42/44 MAPK or JNK; (3) IL-1beta acts through a Rac-dependent pathway, but the downstream effector is not known; and (4) IL-1beta activation of p38 kinase is partially involved in regulation of the hBNP promoter, targeting the proximal M-CAT element.

Animals↗
PubMed1999

Prediction of adult overweight during the pediatric years.

Obesity in adults is associated with an increased mortality rate from various diseases. Childhood overweight or obesity may persist into adulthood, and for this reason it is important to identify such children at risk. The data were taken from a larger longitudinal growth study of 3650 full-term and healthy Swedish babies followed from birth to 18 y of age. Body mass index (BMI) was used to estimate (during the pediatric years) the risk of obesity at 18 y of age. A probability chart for becoming overweight (>25 kg/m2) by 18 y of age was constructed, For example, in girls, a BMI of 16 kg/m2 at 4 y of age is associated with a 20% risk of attaining a BMI value over 25 kg/m2 at 18 y, and in boys at 4 y of age, a BMI of 19 kg/m2 leads to a 60% risk that they will have a BMI value over 25 kg/m2 at 18 y. The probability risk charts for adult overweight developed here is the first one presented. They provide an easy and novel instrument to use to identify those children who are at high risk of becoming obese adults, so that they may have clinical intervention at younger ages.

Adolescent↗
PubMed1999

[The relationship between p53 protein and c-erb B-2 expression and apoptosis in colorectal cancer].

In order to elucidate the relationship between tumor growth and various kinds of gene expression and the occurrence of apoptosis in the front portion of neoplastic invasion, 57 advanced colorectal cancers were studied by immunohistochemical staining of p53, c-erb B-2, the TUNEL method and electron microscopy. Light microscopically, the columnar epithelial cells of adenocarcinoma frequently showed a decrease in high and a fall off into the lumen in tumor invasive forefront. Immunohistochemically the positive rate of p53 and c-erb B-2 in tumors with high vascular invasion were higher (p < 0.05) than in those with low vascular invasion. There was a close correlation between the vascular or lymphatic invasion and positive immunoreactivity of p53 and c-erb B-2. The apoptosis index was demonstrated to be related to vessel invasion, over expression of p53 and inflammatory cell infiltration around the front portion of the tumor invasion. These results suggested that p53. c-erb B-2 and the apoptosis index should be evaluated in conjunction with the prognostic factors in colorectal cancer. The infiltrative inflammatory cells may induce apoptosis of the tumor cells.

Adult↗
PubMed1999

Acellular vaccines containing reduced quantities of pertussis antigens as a booster in adolescents.

OBJECTIVE: To evaluate the immunogenicity and reactogenicity of an acellular pertussis vaccine (pa) either formulated with diphtheria and tetanus toxoids (dTpa) or administered consecutively with a licensed tetanus and diphtheria vaccine (Td) as a 5th dose in adolescents. METHODS: A total of 510 healthy children 10 to 13 years of age were assigned randomly, using a single-blind design, to receive either the dTpa vaccine or the Td vaccine with the pa vaccine 1 month later. The quantities of 3 pertussis antigens (pertussis toxin, filamentous hemagglutinin, and pertactin) in the dTpa and the pa vaccines were one third of those of the Infanrix vaccine (SmithKline Beecham Biologicals, Rixensart, Beligium) licensed for use in infants. For enzyme-linked immunosorbent assay measurement of serum immunoglobulin G antibodies and proliferation assay of peripheral blood mononuclear cells, blood samples were obtained before and 1 month after immunization. Local and systemic reactions were recorded on diary cards for 15 days after immunization. RESULTS: After immunization with dTpa or pa, significant and comparable rises in geometric mean values of antibodies (12- to 46-fold) and proliferations (8- to 18-fold) to each of the pertussis antigens were noted. After immunization with dTpa or Td, significant rises in geometric mean values of antidiphtheria and antitetanus antibodies (35- to 76-fold) were noted, and all subjects had values of these antibodies >/=.1 international units/mL. The dTpa and pa vaccines were at least as well tolerated as the licensed Td vaccine. CONCLUSIONS: Booster immunization of adolescents with an acellular vaccine containing reduced quantities of pertussis antigens in addition to diphtheria and tetanus toxoids induces good responses in both arms of the immune system without an increase in adverse reactions.

Adolescent↗
PubMed1999

Extracting noun phrases for all of MEDLINE.

A natural language parser that could extract noun phrases for all medical texts would be of great utility in analyzing content for information retrieval. We discuss the extraction of noun phrases from MEDLINE, using a general parser not tuned specifically for any medical domain. The noun phrase extractor is made up of three modules: tokenization; part-of-speech tagging; noun phrase identification. Using our program, we extracted noun phrases from the entire MEDLINE collection, encompassing 9.3 million abstracts. Over 270 million noun phrases were generated, of which 45 million were unique. The quality of these phrases was evaluated by examining all phrases from a sample collection of abstracts. The precision and recall of the phrases from our general parser compared favorably with those from three other parsers we had previously evaluated. We are continuing to improve our parser and evaluate our claim that a generic parser can effectively extract all the different phrases across the entire medical literature.

Linguistics↗
PubMed1999

[Monitoring of serum lidocaine concentration in tumescent liposuction infiltrated with high-dosage lidocaine and its clinical significance].

OBJECTIVE: This study was carried out to determine the maximum and safe dosage of lidocaine administered in tumescent liposuction. METHODS: In 14 cases of tumescent liposuction using high-dosage, low-concentration lidocaine as local infiltration anesthetic, serum lidocaine concentrations were monitored with automated fluorescence polarization analysis. RESULTS: The time-concentration curve together with clinical manifestations indicated that in tumescent liposuction, lidocaine, under a concentration of 0.1 mg/ml mixed with 1/1,000,000 to 1/2,000,000 epinephrine, could be administered with a dosage of 35 mg/kg body weight as a local infiltration anesthetic while the serum lidocaine was still within the safety limit and no signs of intoxication manifested. The resulting diminution both in pain and blood loss during the operation enhanced the overall operation safety and suction volume. CONCLUSION: This study provides the basis for high-dosage lidocaine administration in tumescent liposuction.

Adult↗
PubMed1999

[Study on the expression of calreticulin in hypertrophic scar-derived fibroblasts].

OBJECTIVE: To investigate the expression level and intracellular distribution of calreticulin(CRT) in hypertrophic scar-derived fibroblasts(HSF) and normal skin-derived fibroblasts(NSF). METHODS: Using anti-CRT antibody, CRT was detected in HSF and NSF by immunocytochemistry and ELISA technique. RESULTS: CRT was present in the cytoplasm and nuclei in proliferating HSF or NSF in culture, but HSF possessed significantly higher expression level of CRT than NSF(P < 0.01). When these cells (HSF and NSF) were fused, neither intracellular nor intranuclear staining for CRT was observed. CONCLUSION: In HSF and NSF, the distribution of CRT is widespread. Because of its abundant expression in HSF, we postulate that CRT as a multifunctional protein plays an important role in Ca2+ sequestering, integrin-mediated signalling and cell adhesion.

Adolescent↗
PubMed1999

[Human preadipocyte culture and the establishment of hyperplasia and hypertrophy model].

OBJECTIVE: To better understand hyperplasia and hypertrophy properties of human adipose tissue. METHODS: Using an "adhesion-ceiling" culture strategy, fibroblast-like cells from adult pure adipose granules were successfully cultured. RESULTS: The cells were highly homogeneous, highly proliferative and with a high differentiation rate. Their dynamic morphological changes, growth curve, glycerophosphate dehydrogenase pattern, oil red O staining, and reaction to insulin and dexamethasone all verified their preadipocyte identity. Under controlled conditions, the preadipocytes replayed their in vivo hyperplasia and hypertrophy process. CONCLUSION: In mature human adipose tissue there exist functionally active fractions that can be modified. This study laid the basis for further probing into obesity and fat autotransplantation.

Adipocytes↗
PubMed1999

[The clinical study of pulmonary emphysema with pulmonary fibrosis].

OBJECTIVE: Emphysema and interstitial pulmonary fibrosis are two different diseases in clinical manifestation and pathology, but it was noticed that there were cases diagnosed as pulmonary emphysema and pulmonary fibrosis. It is necessary to study the relationship between the clinical aspects of these cases. METHODS: 11 patients with emphysema and pulmonary fibrosis were found in the past five years. Clinical symptoms, radiographic features, arterial blood-gas, lung function testing and computed tomography of the chest were analyzed. RESULTS: These patients had a long history of cigarette-smoking. Their clinical features are those of both emphysema and pulmonary fibrosis. CONCLUSIONS: Although emphysema and interstitial pulmonary fibrosis are two different diseases, they could coexist in some patients. Their clinical features do not like either of the two diseases. HRCT is an important method for discovering the coexistance of pulmonary emphysema and interstitial fibrosis.

Diagnosis, Differential↗