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Biomedical subjects

H H Huang

Publications and source records attributed to H H Huang.

At least 37 records · Page 2Linked to original sources
PubMed2000

Mechanisms mediating the effects of IL-3 gene expression on tumor growth.

IL-3 gene expression within tumors leads to host-cell infiltration, particularly by macrophages, slower tumor growth, and enhanced immunogenicity. Surprisingly, tumor-associated macrophages (TAMs) from within FSAN-JmIL3 tumors had decreased expression of TNF-alpha and iNOS. On short-term culture, TAMs from FSAN-JmIL3 tumors regained their capacity to produce TNF-alpha and NO, indicating that they were primed in vivo. In vitro experiments were unable to demonstrate differences between FSAN-JmIL3 and FSAN tumor cells in their ability to stimulate TNF-alpha production by TAMs. In the absence of evidence that TAM activation was responsible for the slower growth of FSAN-JmIL3 tumors, the response of tumor cells to these effector molecules was studied. TNF-alpha and NO were cytotoxic for FSAN-JmIL3 cells but growth stimulatory for FSAN. These tumor-related phenotypic changes may contribute as much if not more than functional changes in host infiltrating cells to the slower growth of FSAN-JmIL3 tumors in vivo.

Animals↗
PubMed2000

[Study on hydroxylated metabolites of benproperine in human urine].

AIM: To investigate the hydroxylation process of benproperine in humans. METHODS: After an oral administration of 60 mg benproperine to ten healthy male volunteers, urine samples collected within 0-24 h were extracted by solid phase extraction and analyzed by liquid chromatography-ion trap mass spectrometry. A microbial transformation of benproperine combined with semi-preparative HPLC was used to get two reference substances of the hydroxylated metabolites, and their structures were then elucidated by NMR. Furthermore, the structures of conjugated metabolites were speculated based on their characteristics in MS fragmentation. RESULTS: Five hydroxylated metabolites of benproperine and some of their conjugates with endogenous glucuronic acid or sulfuric acid were found in urine of volunteers after the dose. The structures of two metabolites were identified as 4"-hydroxybenproperine and 4"'-hydroxybenproperine by comparison of HPLC retention times and mass spectra with those of authentics obtained from the microbial transformation. CONCLUSION: Hydroxylation of benproperine occurs preferentially at para-position of the alkoxyl group in the aromatic ring. The hydroxylated metabolites of benproperine in human urine mainly exist as their glucuronic acid or sulfuric acid conjugates.

Adult↗
PubMed1999

Preamplifier with a second-order high-pass filtering characteristic.

A new preamplifier for suppressing low-frequency interference is presented. The proposed preamplifier, with its front end being implemented by an instrumentation amplifier, enjoys the following advantages: differential high-pass filtering, high input impedance, high common--mode rejection ratio and low passive sensitivity. This circuit can be realized with commercial operational amplifiers with enough phase margin, or fabricated in a chip for practical measurement of physiological signals.

Electric Impedance↗
PubMed1998

Craniofacial pattern of young adults with various types of malocclusion.

Craniofacial morphological characteristics of young adults with various malocclusions were investigated. Cephalometric radiographs of 100 Class I, 100 Class II, and 100 Class III cases were selected and subjected to counterpart analysis as described by Enlow. Results of individuals with normal occlusion revealed a mean value of 38.75 degrees for the angle of the middle cranial fossa relative to the posterior maxillary plane alignment (MCF/PM). This value was used as the basis for intrinsic alignment comparisons for all the other various parts. Classes I and II malocclusions were classified as either type A or B, depending on whether point A or B was protrusive in the functional occlusal plane (FOP). We found that type B was more common for Class I malocclusion. Further, these cases exhibited an underlying Class III character. We also noted that B groups had different structural craniofacial patterns relative to those seen in A groups. The difference between Class IA and Class IIA, or between Class IB and Class IIB was slight but quantitative. Class III and Class IIA individuals had distinctly different and essentially opposite underlying patterns. However, the composite compensatory result in Class IB case was, for the most part, effective.

Adult↗
PubMed1997

Time-frequency spectral analysis of heart rate variability during induction of general anaesthesia.

We have examined the spectral components of heart rate variability (HRV) during induction of anaesthesia with thiopentone, tracheal intubation and subsequent inhalation of isoflurane-nitrous oxide. Commonly used spectral analysis methods such as fast Fourier transformation or autoregressive modelling require stationary data and are not suitable for the rapidly changing HRV data in this period. An advanced spectral analysis method, time-frequency analysis, which can treat non-stationary data, was used in this study. Multiple spectra were generated to demonstrate the time-related spectral components of HRV. Mid-frequency power (MF, 0.08-0.15 Hz), high-frequency power (HF, 0.15-0.5 Hz) and MF/HF ratio at baseline, after induction (before intubation), immediately after intubation and during maintenance periods were calculated and compared. MF and HF powers decreased after induction and were reduced further in the maintenance period but MF/HF ratio remained unchanged after induction. Immediately after intubation MF and HF powers did not differ significantly from the immediate pre-intubation values, but MF/HF ratio did.

Adult↗
PubMed1997

Elimination of interference component in Wigner-Ville distribution for the signal with 1/f spectral characteristic.

A new technique for interference-term suppression in Wigner-Ville distribution (WVD) is proposed for the signal with 1/f spectrum shape. The spectral characteristic of the signal is altered by f alpha filtering before time-frequency analysis and compensated after analysis. With the utilization of the proposed technique in smoothed pseudo Wigner-Ville distribution, an excellent suppression of interference component can be achieved.

Heart Rate↗
PubMed1996

Cytotoxic effects of anthrax lethal toxin on macrophage-like cell line J774A.1.

The cytotoxic effects of anthrax lethal toxin purified from an avirulent strain were examined on mouse macrophage-like J774A.1 cells. Cell death induced by high concentration of purified lethal toxin had the characteristics of necrosis. At lower concentrations, the toxin caused no morphological change and most of the cells were viable. Interestingly, apoptotic cells were observed when the cells were preincubated with a serine/threonine phosphatase inhibitor, calyculin A, and then exposed to a toxin concentration of 0.1 microg/ml. This is the first report that lethal toxin of the anthrax bacillus can induce both necrosis and apoptosis and that protein phosphatases are implicated in the regulation of bacterial toxin-induced apoptosis.

Animals↗
PubMed1996

Testicular blood flow following spinal cord injury in the Sprague Dawley rat.

The causes of poor semen quality following spinal cord injury (SCI) are unknown. One possible mechanism is decreased testicular blood flow. Chronic testicular ischemia in non-SCI animals has been shown to have significant adverse impact on spermatogenesis. This study was designed to evaluate testicular blood flow following SCI in the Sprague Dawley rat. Testicular blood flows were determined in 11 rats with SCI at thoracic level nine (T9) and six sham control rats three days prior and three days and 14 days after SCI. Testicular blood flow velocity was measured with a Doppler flow probe. Blood flows were compared between groups using T-tests. There were no significant changes in blood flow in the sham operated rats three or 14 days after surgery. However, three days after SCI, blood flow had decreased in the SCI rats to 78 +/- 5 percent of the pre-SCI flow (t = -4.65 with 10 df, p < 0.001). At 14 days after SCI, blood flow was still decreased to 77 +/- 8 percent, (t = -3.40 with 3 df, p < 0.05). This study established that following SCI, testicular blood flow decreases in the Sprague Dawley rat.

Animals↗
PubMed1996

Perioperative changes of plasma endothelin-1 concentrations in patients undergoing cardiac valve surgery.

Twenty-one patients who underwent cardiac valvular replacement procedures were studied to determine the perioperative changes of plasma endothelin-1 (ET-1) concentration and disposition of ET-1 in the pulmonary and systemic vasculature between patients with elevated (over 20 mmHg) mean pulmonary artery pressure and patients with normal pulmonary artery pressure. The overall profile alterations of plasma ET-1 concentration did not differ between the two groups of patients. The plasma ET-1 levels in the pulmonary artery and right atrium were significantly higher in patients with high pulmonary artery pressure than in patients with normal pulmonary artery pressure. Before cardiopulmonary bypass, significant pulmonary extraction of the plasma ET-1 existed in patients with high pulmonary artery pressure but the pulmonary extraction was not seen after bypass. There was no transpulmonary difference of the plasma ET-1 concentration in patients with normal pulmonary artery pressure either before or after bypass. The high levels of ET-1 in the pulmonary circuit and the pulmonary extraction of the ET-1 in patients with high pulmonary artery pressure might be a protective mechanism for rheumatic valvular patients with elevated pulmonary artery pressure.

Endothelin-1↗
PubMed1996

Blood and central venous pressure responses after serial tourniquet deflation during bilateral total knee replacement.

Thirty-five patients who underwent one-stage bilateral total knee replacement were included in this study to determine whether there was any difference in hemodynamic effects following the deflation of the first and second tourniquets. The values of hemodynamic variables were not significantly different immediately before either the first or the second tourniquet release as compared to preoperative values. The changes in heart rate after the release of the first and second tourniquets showed similar patterns. The systolic and diastolic blood pressure decreased significantly after deflation of the first and second tourniquets. However, the decrease was more marked after the second tourniquet deflation. The level of central venous pressure decreased significantly after the release of the first and second tourniquets but the patterns of change were not significantly different. The need for administration of ephedrine was also higher after the deflation of the second tourniquet than after the first. We conclude that the blood pressure changes after the second tourniquet deflation are more pronounced than those following the first tourniquet deflation. Anesthesiologists must be aware of this phenomenon and prevent marked hemodynamic changes that could be detrimental to high-risk patients.

Aged↗
PubMed1995

The effect of cerebrospinal fluid dilution of isobaric 0.5% bupivacaine used for spinal anaesthesia.

A prospective study was conducted to see the effect on spinal anaesthesia of the dilution of isobaric 0.5% bupivacaine with cerebrospinal fluid. Sixty patients were randomly allocated to three groups. In group 1, patients received 3 ml isobaric 0.5% bupivacaine intrathecally without aspirating cerebrospinal fluid. In groups 2 and 3, cerebrospinal fluid 1 ml and 2 ml was aspirated respectively and mixed with 3 ml isobaric 0.5% bupivacaine. A total volume of 4 ml in group 2 and 5 ml in group 3 was administered. Thus, the volume of cerebrospinal fluid remained unchanged. Pinprick analgesia and motor block was evaluated from induction until recovery. No differences in onset time, duration and 'two segments regression' were noticed. The only statistical difference was the time to reach complete motor block, which was shorter in group 1 as compared to groups 2 and 3 (6.9 SD 1.4 min versus 11.3 SD 3.0 and 13.5 SD 3.9 min respectively). The mean value of maximum decrease in systolic blood pressure was small, being less than 15% of the pre-operative value for each group. In conclusion, the effect of diluting isobaric 0.5% bupivacaine with cerebrospinal fluid, 1 ml and 2 ml, is minimal and it is an unnecessary procedure with limited clinical effect.

Adult↗
PubMed1994

Role of urinary cytology and urinary deoxyribonucleic acid flow cytometry in the diagnosis of bladder cancer.

In order to determine the diagnostic efficiencies of urinary cytology and urinary deoxyribonucleic acid (DNA) flow cytometry (FCM) in the detection of bladder cancer, 92 patients were studied from March 1991 to the end of July 1992. Thirty cases had previously undergone operation for bladder cancer and 62 cases were suspected as bladder cancer. One to three fresh voided urine samples from the same patient were sent for conventional urinary cytology and urinary DNA FCM analysis. Each patient underwent cystoscopic examination or surgical histopathologic examination to verify the presence of bladder tumor. From December 1991 to the end of July 1992, 52 cases were analyzed and reported separately due to improved FCM techniques. Urinary DNA FCM showed a higher sensitivity than cytology in both the total (p < 0.05) and the second half time period (p < 0.01). Cytology showed a statistically superior specificity against FCM in the total period (p < 0.05) but not in the second half time period (p > 0.1). Combining sensitivity and specificity, FCM's overall accuracy rate was better than cytology in the second half time period (p < 0.05). To clarify the specific features of bladder tumors in which FCM showed superior sensitivity than cytology, we analysed the detection rates for various features of bladder tumor in the second half time period. FCM was better than cytology in detecting multiple tumors, small tumors and papillary tumors. No statistical differences were obtained if tumors were single, larger than 3 cm or flat in outer surface. To our knowledge, no previous similar analysis has been reported in the literature.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Differences in temperature changes between pediatric and adult patients after cardiopulmonary bypass.

Nasopharyngeal (NPT) and rectal (RT) temperatures were continuously monitored in 51 adult or pediatric patients undergoing cardiac surgical procedures until 1 hour after the termination of cardiopulmonary bypass (CPB). The measurement also included the lowest NPT achieved and the dwelling time at that temperature on CPB, the rewarming time, the time on CPB, and the time that the chest remained opened after CPB. After the termination of CPB, the decrease of NPT (afterdrop) was significantly greater in the adult group than in the pediatric group. The mean decrease in adult patients was 1.34 +/- 0.65 degrees C versus 0.63 +/- 0.8 degrees C in pediatric patients. The combination of the NPT at the end of bypass (EndNPT), body weight times the EndNPT, and the dwelling of the lowest temperature times the EndNPT could predict 45% of the afterdrop. It is concluded that afterdrop occurs to a lesser degree in pediatric patients than in adults. This may be due to more efficient supplying of external heat to pediatric patients in whom there is a larger body surface area to weight ratio.

Adult↗
PubMed1993

Validity and feasibility of nasopharyngeal end-tidal carbon dioxide tension monitorings: a novel approach in spontaneous breathing patients.

Conventional end-tidal CO2 (Pe'CO2) monitoring is difficult and impractical in nonintubated patients who are either sedated or anesthetized while spontaneous respiration is maintained. An alternative technique using nasopharyngeal end-tidal carbon dioxide tension (PNe,CO2) has been developed. The present study evaluates the feasibility and validity of PNe,CO2 as a reliable respiratory monitoring method. Sixty patients in ASA class status I or II and scheduled for elective surgery were divided into two groups. In group 1 (n = 30), conventional Pe'CO2 was used in intubated patients under general anesthesia. In group 2 (n = 30), PNe,CO2 monitoring was used in patients under regional anesthesia with spontaneous respiration maintained. A 12 FG suction catheter, connected to the sampling tube of a CO2 analyzer, was inserted via the nasal airway to within 1 cm of the nasopharyngeal orifice. Arterial blood gas (PaCO2) was sampled 25 minutes after the operation began, Pe'CO2 (group 1) and PNe,CO2 (group 2) were recorded simultaneously. In both groups, PaCO2 was highly correlated with Pe'CO2 (r = 0.6938) and PNe,CO2 (r = 0.8613). The difference between the two values, (a-e')PCO2 = 0.35 +/- 0.33kPa and (a-Ne')PCO2 = -0.1 +/- 0.51kPa, indicates that PNe,CO2 is more closely correlated to PaCO2 than conventional Pe'CO2. The reduced (a-Ne')PCO2 in group 2 may be explained by CO2 rebreathing and a reduced respiratory deadspace during anesthesia and spontaneous breathing. Interestingly, 60% of the (a-Ne')PCO2 measurements were negative values, suggesting that PNe,CO2 and a spatial V/Q mismatch is caused by sedation; higher CO2 production and CO2 rebreathing may explain the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Polymerase chain reaction to detect human cytomegalovirus in livers of infants with neonatal hepatitis.

Neonatal hepatitis is closely related to human cytomegalovirus infection in Taiwan, a conclusion based on serological and urine culture studies. To obtain more direct evidence further relating cytomegalovirus to the pathogenesis of neonatal hepatitis, the cytomegalovirus genome was studied in the liver tissues of 50 infants with neonatal hepatitis using the polymerase chain reaction (PCR). Liver tissues from 26 infants with biliary atresia and another 30 infants and children with diagnoses other than neonatal hepatitis, cholestasis, or hepatitis were also studied for comparison. Sequences from the immediate early gene 1 and 2 regions were used as primers. The liver tissues from 23 (46%) of the 50 infants with neonatal hepatitis were positive for cytomegalovirus genome, whereas those of 2 of the 26 infants with biliary atresia and none of the liver tissues from 30 infants and children without neonatal hepatitis were positive for cytomegalovirus genome, by PCR. The results of PCR correlated well with that of serology and urine culture. This study provides further evidence of cytomegalovirus in the pathogenesis of neonatal hepatitis.

Base Sequence↗