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Biomedical subjects

H H Huang

Publications and source records attributed to H H Huang.

At least 19 recordsLinked to original sources
PubMed2006

Community-acquired pneumonia in Shanghai, China: microbial etiology and implications for empirical therapy in a prospective study of 389 patients.

The aim of this multicenter study was to identify the causative pathogens of community-acquired pneumonia (CAP) in Shanghai, China, and to determine their susceptibility to antimicrobial agents. Pathogens obtained from 389 patients with documented CAP during 2001-2003 were identified by multiple diagnostic tools that included bacterial culture, polymerase chain reaction (PCR), and specific immunological assays. Susceptibility of the bacterial isolates was tested by the broth microdilution method. A specific pathogen was identified in 39.8% (155/389) of the patients: Haemophilus influenzae (n=80), Klebsiella spp. (n=15), Streptococcus pneumoniae (n=12), Staphylococcus aureus (n=6), Moraxella catarrhalis (n=1), other gram-negative organisms (n=9), and atypical pathogens that comprised Mycoplasma pneumoniae (n=42), Chlamydia pneumoniae (n=17), and Legionella pneumophila (n=2). Most H. influenzae isolates were susceptible to ampicillin (88.3%), and all were susceptible to macrolides. Of the S. pneumoniae isolates, 75% (9/12) were susceptible to penicillin, while 25% (3/12) were intermediately susceptible. H. influenzae and atypical pathogens are among the most important pathogens of CAP. Ampicillin, cephalosporins, and the newer fluoroquinolones can be used as empirical therapy for CAP in the Shanghai area. The efficacy of monotherapy with newer macrolides for CAP caused by S. pneumoniae requires further evaluation.

Adolescent↗
PubMed2005

Biotransformation of pantoprazole by the fungus Cunninghamella blakesleeana.

To investigate the biotransformation of pantoprazole, a proton-pump inhibitor, by filamentous fungus and further to compare the similarities between microbial transformation and mammalian metabolism of pantoprazole, four strains of Cunninghamella (C. blakesleeana AS 3.153, C. echinulata AS 3.2004, C. elegans AS 3.156, and AS 3.2028) were screened for the ability to catalyze the biotransformation of pantoprazole. Pantoprazole was partially metabolized by four strains of Cunninghamella, and C. blakesleeana AS 3.153 was selected for further investigation. Three metabolites produced by C. blakesleeana AS 3.153 were isolated using semi-preparative HPLC, and their structures were identified by a combination analysis of LC/MS(n) and NMR spectra. Two further metabolites were confirmed with the aid of synthetic reference compounds. The structure of a glucoside was tentatively assigned by its chromatographic behavior and mass spectroscopic data. These six metabolites were separated and quantitatively assayed by liquid chromatography-ion trap mass spectrometry. After 96h of incubation with C. blakesleeana AS 3.153, approximately 92.5% of pantoprazole was metabolized to six metabolites: pantoprazole sulfone (M1, 1.7%), pantoprazole thioether (M2, 12.4%), 6-hydroxy-pantoprazole thioether (M3, 1.3%), 4'-O-demethyl-pantoprazole thioether (M4, 48.1%), pantoprazole thioether-1-N-beta-glucoside (M5, 20.6%), and a glucoside conjugate of pantoprazole thioether (M6, 8.4%). Among them, M5 and M6 are novel metabolites. Four phase I metabolites of pantoprazole produced by C. blakesleeana were essentially similar to those obtained in mammals. C. blakesleeana could be a useful tool for generating the mammalian phase I metabolites of pantoprazole.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2004

Expression of transforming growth factor beta (TGF-beta1) in human epithelial alveolar cells: a pro-inflammatory mediator independent pathway.

Regulation of transforming growth factor beta 1 (TGF-beta1) expression remains unclear. Inflammation has been inferred to play a major role in stimulating TGF-beta1 production since high concentrations of TGF-beta1 have been found in the lungs of patients with various diffuse inflammatory lung diseases. To establish an association between inflammation and TGF-beta1 expression, human alveolar epithelial (A549) cells were co-cultured with lipopolysaccharide (LPS), Tumor necrosis factor alpha (TNFalpha), Interleukin 1 beta (IL-1beta) and Interleukin 8 (IL-8) for 12 hours. Total and bioactive TGF-beta1 protein were then measured. A549 cells transiently transfected with a plasmid containing the TGF-beta1 promoter linked to a luciferase reported gene were then co-cultured with the same inflammatory peptides for 12 hours and TGF-beta1 promoter activity determined. Nuclear transcription factors AP-1 (c-jun) or NF-kappa (p65, p50 and p105) were over expressed in A549 cells transiently transfected with the TGF-beta1 promoter and TGF-beta1 promoter activity subsequently measured. Stimulation with inflammatory signals LPS, TNFalpha, IL-1beta, IL-8 resulted in no increase of total or bioactive TGF-beta1 activity above constitutive concentrations in vitro. TGF-beta1 promoter activity was also unchanged from baseline levels in response to the same inflammatory peptides. Expression of c-jun however led to significant increases of TGF-beta1 promoter activity over constitutive levels. In contrast p65 and p105 expression resulted in inhibition of TGF-beta1 promoter activity below baseline levels. We conclude that in a human alveolar epithelial cell line, inflammation does not regulate TGF-beta1 expression. These studies suggest that in lung pathologies such as asthma, lung fibrosis and CLD, TGF-beta1 production may involve pathways independent of inflammatory mediators LPS, TNFalpha, IL-1beta and IL-8.

Cell Line↗
PubMed2002

Low frequency of HLA-B*2706 in Taiwanese patients with ankylosing spondylitis.

The presence of HLA-B27 in patients affected with ankylosing spondylitis (AS) was well established prior to the advent of DNA typing of various genes within the major histocompatibility complex (MHC) in humans. However, molecular typing of the MHC genes revealed that B27 comprises a motley assortment of alleles, some of which are strongly positively associated with the disease and some of which are negatively associated with the disease. B*2706 was reported to have a negative association with AS in the Thai population and in Chinese Singaporeans. We report here our finding of an absence of B*2706 in 184 Taiwanese AS patients.

Adolescent↗
PubMed2001

Catalytic decomposition of hydrogen peroxide and 2-chlorophenol with iron oxides.

The aim of this study was to examine the catalyzed decomposition of hydrogen peroxide and 2-chlorophenol (2-CP) in the presence of iron oxides. Granular ferrihydrite, goethite, and hematite were selected as catalysts in this study. 2-CP was used as the model compound because it is a typical toxic compound and has not been investigated in the catalytic decomposition by iron oxides. The catalytic activity for hydrogen peroxide decomposition followed the sequence: granular ferrihydrite > goethite > hematite. However, hematite exhibited the highest activity in catalyzing 2-CP oxidation. The oxidation efficiency of 2-CP corresponded with the inverse sequence of specific area and pHpzc of the iron oxides. The catalytic activity of granular ferrihydrite was affected significantly by the mixing speed and particle size for its large value of Thiele modulus (phi) and Damkohler number (Da). The strong diffusion resistance for granular ferrihydrite was attributed either to its microporous structure or to the formation of oxygen in the pores of the iron oxide leading to the unexpected catalytic activity of granular ferrihydrite to hydrogen peroxide and 2-CP.

Catalysis↗
PubMed2001

Detection of cytomegalovirus infection in a patient with febrile ulceronecrotic Mucha-Habermann's disease.

BACKGROUND: Febrile ulceronecrotic Mucha-Habermann's disease (FUMHD) is a severe and very rare variant of pityriasis lichenoides et varilioformis acuta, which is characterized by large coalescing, and ulceronecrotic maculopapules or plaques. Morphological changes of the skin accompanied by persistent high fever and several constitutional symptoms have suggested virus infection in patients with FUMHD. However, the available information of viral origin is limited. In this study we investigated the relationship of cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 8 (HHV8), type I human T-cell lymphotropic virus (HTLV-I), and parvovirus B19 (PVB19) with FUMHD in a Taiwanese patient. METHODS: The existence of CMV, EBV, HHV8, HTLV-I, and PVB19 was determined by polymerase chain reaction (PCR). The presence of CMV in the endothelial cells was characterized by in situ hybridization (ISH) and immunohistochemistry (IHC). RESULTS: Serologic immunoglobulin to CMV and IHC identification of CMV late gene in the biopsy specimen indicated that the patient was infected with CMV. Detection of CMV was confirmed by PCR and ISH. CONCLUSIONS: These results indicate that FUMHD is associated with dermal CMV manifestation. Nonetheless, the induction mechanism of FUMHD with CMV infection has yet to be determined.

Acyclovir↗
PubMed2001

Characteristic structural features of schistosome cercarial N-glycans: expression of Lewis X and core xylosylation.

Schistosomal egg N-glycans are the only examples in nature that have been structurally shown to contain beta2-xylosylation, alpha6-fucosylation, and alpha3-fucosylation on the N,N'-diacetyl chitobiose core. We present evidence that core difucosylated and xylosylated N-glycans are characteristics of Schistosoma japonicum eggs but not of the cercariae and adults, for which neither core xylosylation nor alpha3-fucosylation could be readily detected. In contrast, a majority of the N-glycans from Schistosoma mansoni cercariae but not the adults are core xylosylated. Tandem mass spectrometry analysis coupled with chromatographic mapping, sequential exoglycosidase digestion, and methylation analysis were employed to unambiguously define the structures of core beta2-xylosylated, alpha6-fucosylated N-glycans from S. mansoni cercariae. Unexpectedly, a majority of these N-glycans were found to carry Lewis X determinant, Galbeta1-->4(Fucalpha1-->3)GlcNAcbeta1-->, on the nonreducing termini of mono- and biantennary structures. The Lewis X-containing glycoproteins were found to be distinct from those carrying the complex, multifucosylated glycocalyx O-glycans reported previously. The corresponding N-glycans from S. japonicum cercariae are likewise dominated by Lewis X termini but without the core xylosylation. We concluded that the invading cercariae present an important and abundant source of Lewis X antigens, which may contribute to the induced humoral response upon infection. Following transformation and development into the adults, the N-glycans synthesized comprise a significantly larger amount of high mannose and fucosylated pauci-mannose structures in comparison with the cercarial N-glycans. A portion of the mono- and biantennary complex types were identified to carry Lewis X and fucosylated LacdiNAc termini, which could also be detected by mass spectrometry analysis on larger, complex-type structures.

Animals↗
PubMed2001

Selective expression of different fucosylated epitopes on two distinct sets of Schistosoma mansoni cercarial O-glycans: identification of a novel core type and Lewis X structure.

The glycobiology of Schistosoma mansoni is dominated by developmentally regulated expression of various fucosylated structures, most notably the Lewis X epitope and a multifucosylated sequence, Fuc alpha1-->2Fuc alpha1-->, in its various forms. For the infective cercarial stage, Lewis X has been structurally identified on glycosphingolipids and N-glycans of total glycoprotein extracts, and a population of multifucosylated glycoproteins were found to carry a unique terminal sequence, +/-Fuc alpha1-->2Fuc alpha1-->[3GalNAc beta1-->4(Fuc alpha1-->2Fuc alpha1--> 2Fuc alpha1-->3) GlcNAc beta1-->3Gal alpha1-->](n), on their O-glycans. Using a mass spectrometry approach coupled with chromatographic separation, sequential exoglycosidase digestion, periodate oxidation, and other chemical derivatization, we demonstrate that Lewis X could also be carried on the cercarial O-glycans, but the two distinctive sets of fucosylated epitopes were conjugated to two different core structures. Lewis X, lacNAc, or single GlcNAc was found to attach directly to the -->3Gal beta1-->3GalNAc core and indirectly via another beta-Gal residue branching off from C6 of the reducing end GalNAc to give a biantennary-like structure. The -->3(+/-Gal beta1-->6)Gal beta1-->3(-->3Gal beta1-->6)GalNAc core thus characterized represents a novel core type for O-glycans. In contrast, the previously characterized multifucosylated terminal sequences were carried on conventional type 1 and 2 cores. The smallest structures of the reductively released O-glycans were defined as GalNAc beta1-->4GlcNAc beta1-->3Gal beta1-->3GalNAcitol with a total of two to four fucoses attached to the terminal lacdiNAc. alpha-Galactosylation of the nonreducing terminal beta-GalNAc instead of fucose capping leads to further elongation with another lacdiNAc unit that could also extend directly from C6 of the reducing end GalNAc and similarly elongated or terminated.

Animals↗
PubMed2001

Time-Frequency analysis of heart rate variability during transient segments.

The spectral characteristics of heart rate variability (HRV) are related to the modulation of the autonomic nervous system. As the physiological condition is changed by such external stimuli such as drugs, postural changes, and anesthesia, or by internal deregulation such as in syncope, adjective autonomic responses could alter HRV characteristics. Time-frequency analysis is commonly used to investigate the time-related HRV characteristics. An alteration of the autonomic regulation resulting in a change in mean heart rate induces a transient component in heart rate, which, with any analysis method based on signals from multiple beats, results in the apparent spread of the spectrum of frequencies. This obscures the spectral components related to the autonomic function. In this paper we investigated the influence of the transient component in several time-frequency methods including the short-time Fourier transform, the Choi-Williams distribution, the smoothed pseudo Wigner-Ville distribution (SPWVD), the filtering SPWVD compensation, and the discrete wavelet transform. One simulated signal and two heart rate signals during general anesthesia and postural change were used for this assessment. The result demonstrates that the filtering SPWVD compensation and the discrete wavelet transform have small spectrum interference from the transient component.

Anesthesia, General↗
PubMed2001

Rapid recovery of spontaneous baroreflex after sevoflurane anesthesia in ambulatory surgery.

BACKGROUND: Although sevoflurane seems to have fulfilled the criteria of ideal anesthetic agent for ambulatory surgery, its effects on intraoperative alteration and postoperative recovery of arterial baroreflex have not been well documented. This study assessed the time required for patients anesthetized with sevoflurane to regain their baseline baroreflex after ambulatory surgeries. METHODS: Ten ASA class I female patients scheduled for minor gynecological operation (D&C) were enrolled in this study. Spontaneous baroreflex sensitivity (SBR) calculated by sequence analysis of beat-to-beat variations in systolic arterial pressure and R-R intervals was recorded before anesthesia (Baseline), during anesthesia (Anesthesia), five min after operation (Post-op 1) and ten min after operation (Post-op 2). Data obtained from Anesthesia, Post-op 1, and Post-op 2 was compared with the Baseline. RESULTS: SBR value determined in Baseline group (28.6 +/- 4.9 ms/mmHg) was significantly different from Anesthesia group (12.2 +/- 2.1 ms/mmHg) and Post-op 1 group (15.8 +/- 1.8 ms/mmHg). Patients regained their conscious baseline baroreflex sensitivity within ten min after sevoflurane was switched off. CONCLUSIONS: Sevoflurane anesthesia depresses SBR and provides a quick SBR recovery upon emergence.

Adult↗
PubMed2001

Lack of intravenous lidocaine effects on HRV changes of tracheal intubation during induction of general anesthesia.

BACKGROUND: Intravenous lidocaine has been widely used for suppressing the autonomic activation from tracheal intubation during induction of general anesthesia. Conventionally, researches of its effectiveness through assessment of heart rate and blood pressure changes obtained by common clinical methods result in the conclusions deduced of much controversy. Heart rate variability is a noninvasive measurement of autonomic regulation and is suitable for the study of this subject. METHODS: 36 ASA class I-II patients undergoing general anesthesia were divided into 3 groups. Besides induction agents, intravenous lidocaine was given 5 min before tracheal intubation in group A, 3 min before intubation in group B and nothing in group C. HRV spectral powers were measured at awake state, anesthetized state before tracheal intubation and anesthetized state after tracheal intubation by time frequency spectral analysis method and comparison was made between the three groups. RESULTS: The HRV spectral power in high frequency (HF) and mid-frequency (MF) power bands and their ratios (MF/HF) were not significantly different among the 3 groups during the 3 observation periods. CONCLUSIONS: There was no evidence to indicate the effectiveness of intravenous lidocaine on the autonomic regulation during tracheal intubation under the influence of induction agents used in general anesthesia.

Anesthesia, General↗
PubMed2001

Demethylation metabolism of roxithromycin in humans and rats.

AIM: To investigate the demethylated metabolites of roxithromycin (RXM) in humans and rats, and to study the antibiotic activity of these metabolites in vitro. METHODS: The demethylated metabolites of RXM in humans and in rats were identified by liquid chromatography-mass spectrometry (LC-MS), and the in vitro antibiotic activities of them against three standard strains were also studied compared with those of the parent drug and some other metabolites of RXM. RESULTS: O-Demethylation of RXM was one of the main metabolic routes of RXM in humans, whereas N-demethylation metabolism was more predominant in rats. O-Demethyl-RXM appeared to be equally effective with RXM. CONCLUSION: The O-demethyl-RXM was an active metabolite in humans, and there were some species differences in RXM demethylation metabolism between humans and rats.

Adolescent↗
PubMed2001

Characteristics of patients at a Taipei summer rock concert festival.

BACKGROUND: Rock concerts are popular mass gatherings in Taiwan. Millions of fans participate in rock concerts in Taiwan each year. However, there were no reports on the characteristics of the patients seen in rock concerts in Taiwan. METHODS: Medical care for a summer rock concert festival held in an outdoor stadium in Taipei was coordinated by emergency physicians of a medical center. About 50,000 attendees participated in the two-night concert. Three stations were set up to provide advanced medical care. A standardized form was used to collect information about patients. RESULTS: A total of 28 cases visited the medical stations, fourteen cases each day. They were aged from 13 to 40 years, with an average of 20.8 +/- 6.4. Twenty-one cases were female and seven were male. Twenty-two (79%) were spectators, five (18%) were on-duty staff, and one was a by-stander. Based on an estimation of totally 50,000 participants in the stadium for this two-night festival, the medical use rate was roughly 5.6 PPTT (patients per ten thousand attendees). The most common major problem was fainting which accounted for 13 cases (46%). Of these 13 cases, three cases (23%) lost consciousness and 12 cases (92%) were female. Sixteen cases (57%) were classified as requiring ALS (advanced life support) and 12 cases (43%) as requiring BLS (basic life support). Most cases improved and were discharged after onsite treatment. Only one case was transferred by ambulance due to persistent chest pain. However, she recovered several hours later. CONCLUSIONS: By this preliminary data, first reported in Taiwan, we found that the most common problem was fainting. More than half of the cases seen at the concert required advanced life support. A well-designed emergency medical service (EMS) system is mandatory to provide services for these events.

Adolescent↗
PubMed2000

Differential change in cardiac baroreflex sensitivity estimated by sequence and spectral analysis during etomidate anesthesia.

Spontaneous baroreflex sensitivity, high-frequency gain, (0.15-0.35 Hz), and mid-frequency gain (0.07-0.14 Hz) are noninvasive measures of cardiac baroreflex function derived by spontaneous sequence and cross-spectral analysis. To demonstrate the difference between these baroreflex estimates, 14 patients received etomidate (0.3 mg/kg bolus and 0.9 mg/kg/h infusion), lidocaine (60 mg), and vecuronium (0.1 mg/kg) by intravenous injection. The authors found that spontaneous baroreflex sensitivity and high-frequency gain were decreased (p <0.05) after etomidate anesthesia, whereas mid-frequency gain was maintained. Spontaneous baroreflex sensitivity, high-frequency gain, and mid-frequency gain, although compared simultaneously, did not change in a parallel manner. In another 5 patients, who received normal saline only, measures were unchanged. The authors conclude that spontaneous baroreflex sensitivity, high-frequency gain, and mid-frequency gain are not interchangeable. Experimental results on baroreflex control depend on the parameter selected.

Adult↗
PubMed2000

Sports and other soft tissue injuries, tendinitis, bursitis, and occupation-related syndromes.

This review highlights three areas: plantar fasciitis, Achilles tendinitis, and carpal tunnel syndrome. The diagnosis and treatment of plantar fasciitis are reviewed; nonsurgical treatments remain the mainstay of management. Several recent articles support the use of night splints. Some novel treatments recently investigated, including low intensity laser irradiation and extracorporeal shock wave lithotripsy, are reviewed, as well as the effectiveness of steroid injection. Novel treatments for Achilles tendinitis are also reviewed, including the use of injection therapy and the treatment approach of one author for the management of Achilles tendon rupture. Nonsurgical techniques in the treatment of carpal tunnel syndrome, such as yoga, ultrasound, noninvasive laser neurolysis, manipulation, nerve and tendon gliding exercises, and medications, are reviewed. Prednisolone was shown to be effective in the treatment of mild to moderate disease and nonsteroidal anti-inflammatory drugs were found to be ineffective.

Athletic Injuries↗