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Y F Huang

Publications and source records attributed to Y F Huang.

69 records · Page 4Linked to original sources
PubMed1993

IV bolus administration of subconvulsive doses of lignocaine to conscious sheep: relationships between myocardial pharmacokinetics and pharmacodynamics.

We have studied relationships between the time-courses of lignocaine concentrations in arterial and coronary sinus blood and myocardial tissue, and negative inotropic effects on the myocardium, after i.v. bolus administration of 50-, 75- or 100-mg doses of lignocaine to conscious, chronically instrumented sheep. Peak arterial and coronary sinus blood lignocaine concentrations occurred 26-38 s before and 29-78 s after the maximum decreases in myocardial contractility, respectively. Peak myocardial concentrations occurred simultaneously with the maximum decreases in myocardial contractility, except for the 100-mg doses. Anti-clockwise hysteresis occurred only between arterial blood lignocaine concentrations and the negative inotropic effect. It was concluded that, after short-term i.v. administration, only the myocardial concentrations of lignocaine were in pseudoequilibrium with the negative inotropic effects of the lignocaine on the myocardium.

Animals↗
PubMed1993

Growth factor modulation of insulin-like growth factor-binding proteins in rat osteoblast-like cells.

Insulin-like growth factors (IGFs) stimulate growth and differentiation of osteoblasts in culture, and these biological functions can be modulated by their binding proteins (IGFBPs). Previous studies have shown that IGFBP-2 is the major IGFBP synthesized by fetal rat osteoblast-like (ROB) cells, which also secret a minor 24-kilodalton IGFBP, presumably IGFBP-4. In this study we examined the modulation of the abundance of IGFBPs by various growth factors. By immunoprecipitation and ligand blotting, we have proved that the 24 kilodalton protein, which appeared at 25 kilodalton in the present study, is IGFBP-4, whose level was strongly enhanced by basic fibroblast growth factor (bFGF) and platelet-derived growth factor BB homodimer. Induction of IGFBP-4 by these factors was detected at 1 nM (10- to 30-fold) and increased to 50- to 70-fold of control at 10 nM. The abundance of IGFBP-4 was also increased but to a lesser degree by transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF). As opposed to the actions of other growth factors, TGF-beta 1 substantially lowered the levels of IGFBP-2 and IGFBP-4. PTH and PTH-related peptide did not induce IGFBPs in ROB cells. This is in contrast to the findings from a malignant rat osteoblast-like cell line, UMR 106-01. Since the level of IGFBP-4 after bFGF treatment remained elevated in the presence of hydroxyurea, the induction was likely to be independent of the stimulatory effects of these factors on mitogenesis. To further examine the mechanisms by which IGFBPs were regulated, cultures were treated with actinomycin D and cycloheximide with and without bFGF. Although the synthesis of IGFBP-2 and IGFBP-4 were both inhibited by cycloheximide, actinomycin D blocked the synthesis of basal and bFGF-induced IGFBP-4 but not IGFBP-2. Total RNA extracted from ROB cells and hybridized with specific rat complementary DNAs for IGFBP-2 and IGFBP-4 showed single transcripts of 1.3 and 2.2 kilobases, respectively. Regardless of the changes at the protein level, the abundance of IGFBP-4 transcripts was not different from the vehicle-treated controls at 2, 8, and 24 h after bFGF treatment. Similarly, the levels of messenger RNA for IGFBP-2 and IGFBP-4 did not change during the same time course in the TGF-beta 1 treatment. These data demonstrate that in ROB cells, the abundance of IGFBPs is differentially regulated by various growth factors.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

IV bolus administration of subconvulsive doses of lignocaine to conscious sheep: effects on circulatory function.

We have studied the effects of subconvulsive doses of lignocaine on circulatory function in five conscious, chronically instrumented sheep. In the absence of overt signs of central nervous system toxicity, 50-, 75- or 100-mg i.v. bolus doses of lignocaine induced reductions in myocardial contractility, as assessed by the maximum rate of increase in left ventricular pressure (LV dP/dtmax), of 17 (SD 4)%, 25 (4)% and 33 (4)%, respectively. The durations of these reductions in myocardial contractility were 2-3.5 min. There were no significant changes in cardiac output, coronary artery blood flow, mean arterial pressure, heart rate or left ventricular systolic and diastolic pressures. It is concluded that the initial toxic effects of lignocaine are on the heart rather than the central nervous system, as is generally believed. This negative inotropic effect of lignocaine in vivo may be more deleterious to myocardial function when the heart is compromised by pre-existing disease, or the co-administration of other myocardial depressive drugs.

Animals↗
PubMed1991

An assessment of methods for sampling blood to characterize rapidly changing blood drug concentrations.

The accuracy of different blood sampling methods used to characterize rapidly changing blood drug concentrations was examined both in vitro and in vivo. It was shown in vitro that blood sampling methods based on the fraction collection principle failed to characterize a "square wave" change in drug concentration, and there was a 9-16-s delay before achieving 95% of the expected drug concentration. Varying the catheter size and length did not improve the response. This observation is consistent with laminar and/or turbulent flow producing dispersion and mixing of blood of different drug concentrations in the catheter. A sampling method (flush and withdrawal) was developed to minimize these effects. In vivo studies showed that peak blood drug concentrations obtained using this method after an iv bolus of a drug were approximately 25-28% higher than those simultaneously obtained by methods based on fraction collection principles. It is concluded that blood sampling methods based on fraction collection principles can produce significant errors in measured blood drug concentrations. The error is greater the greater the rate of change of the blood drug concentrations.

Animals↗
PubMed1991

Insight into interstitial drug disposition: lymph concentrations of lidocaine, procainamide and meperidine in the hindquarters of unanesthetized and anesthetized sheep.

Drug concentrations in the lymph of the hindquarters of sheep were used to gain insight into drug disposition within the interstitial space. Lidocaine, procainamide and meperidine were each infused into the right atrium of adult merino ewes for 220 min. The time courses of drug concentrations in arterial and inferior vena caval (IVC, draining the hindquarters) blood and hindquarter lymph were determined. It was found that in unanesthetized sheep the mean (+/- S.D., n = 3) lidocaine, procainamide and meperidine concentrations in the hindquarter lymph, were 74 +/- 11, 107 +/- 25 and 94 +/- 17%, respectively, of the arterial and 92 +/- 15, 113 +/- 27 and 134 +/- 28%, respectively, of the IVC blood drug concentrations. Drug binding in lymph, determined by equilibrium dialysis, was not significantly higher than that in blood, except for lidocaine at an initial buffer concentration of 5 micrograms/ml. When the studies were repeated with different animals under halothane anesthesia, the lymph/arterial and lymph/IVC blood drug concentration ratios of the three drugs decreased to 66 +/- 9, 73 +/- 13 and 71 +/- 13% and 77 +/- 8, 88 +/- 19 and 85 +/- 10%, respectively. These values were all significantly lower than those in unanesthetized animals. The results suggest that drug protein binding in interstitial fluid and the status of the microcirculation are important determinants of drug distribution in the interstitial and intracellular spaces. The data also confirm the assumption made in pharmacokinetic studies based upon mass balance principles that the rate of drug removal from organs by lymph is negligible.

Anesthesia↗
PubMed1990

[Therapeutic effect of methyl 5-aminosalicylate on experimental ulcerative colitis in rabbits].

Using the improved Kirsner model of ulcerative colitis in rabbits, we found that the therapeutic effect of methyl 5-amino salicylate hydrochloride (M-5-AS) was similar to that of sulfasalazine (salicylazosulfapyridine, SZ). The length of pathological damage and the range of diffuse ulcers were decreased in comparison with the control group (P less than 0.01, 0.05). Microscopically, tissue repairing at the regions of ulcers and proliferation in serolemma were noted, and the edema in muscular mesenchyme was less evident in the treated rabbits. M-5-AS completely inhibited the spontaneous contraction of rat stomach fundus strips and colon. The IC50 of the resting tone of the 2 tissues were 1.30 +/- 0.39 and 0.72 +/- 0.25 mmol/L, respectively. In addition, M-5-AS antagonized the contraction induced by human fresh semen. The results suggest that the therapeutic mechanism is related to the antagonism of prostaglandins in the inflammatory regions.

Aminosalicylic Acids↗
PubMed1990

A review of botulism in China.

The epidemiological characteristics and etiology of botulism in China, as well as the distribution of different types of Clostridium botulinum in China, are described. Through 1989, 15 provinces and autonomous regions reported the occurrence of botulism. There were 2861 cases involved in 745 outbreaks. Among the cases 421 died, with a case fatality of 14.7%. The main epidemiological characteristics of botulism in China are: (i) the major foods causing botulism are homemade fermented bean products which accounted for 62.6% of the cases; (ii) the incubation period is longer (3 h-54 days) than that described in the western literature (mostly 2-7 days); (iii) the peak occurrence is from February to May; (iv) the progression of symptoms and signs is slower than that of western cases. All types of C. botulinum, with the exception of type G, have been found in China. The distribution of various types of C. botulinum is significantly different between southern and northern China; this is related to the latitude and is correlated with the prevalence of this disease. Most of the botulism outbreaks occurred above 30 degrees north latitude in northern China and outbreaks rarely occurred below 30 degrees north latitude. Nationwide surveys showed that the average detection rate of C. botulinum spores in soil and foods in the northern parts of China was 14.8%, while it was only 2.5% in the south. C. botulinum types A, B, E, and F, which are involved in human botulism, were frequently found in the North, while types C and D, which are involved only in animal intoxication, were found more frequently in the south.

Botulism↗
PubMed1989

[Automatic static quantitative perimetry of the central 30 degrees visual field in normal subjects].

131 normal volunteers (131 eyes) with visual acuities of 20/20 or better were tested by automatic static quantitative perimetry (Octopus-500E) for the central 30 degrees visual field. The results revealed that only 35 eyes (26.7%) had sensitivities at all points tested equal to or better than the age-corrected norms established for the device, and 96 eyes (73.3%) were 5 dB or more below the age adjusted norms at one point at least in areas not adjacent to the blind spot; the farther from the point of fixation, the sensitivity drop became more obvious and with higher frequency. When the central 30 degrees field was divided into five concentric circles, the greatest sensitivity drops appeared in the area between 25-30 degrees. The authors put forward more reasonable criteria for defects in the central 25 degrees visual field by Octopus-500 E Program 36.

Adolescent↗
PubMed1989

[Study on molecular hybridization with biotin-labelled HPV 16 DNA probe in human cervical carcinoma].

Biotin-labelled human papillomavirus (HPV) 16 type DNA probe was prepared by the techniques of molecular biology. And dot hybridization technique was used to detect the HPV 16 homologous sequences in the tissues DNA of human cervical carcinoma. The results indicated that 16 cases out of 28 of the human cervical carcinoma tissues were positive. The positive rate was 57%. The other 4 cases of normal uterine cervix tissues were negative. Only 1 in 4 chronic cervicitis tissues showed positive. The HPV 16 plasmid DNA, as the positive control group, showed strong positive, while lambda-phage DNA was negative. The results have shown that the genome of the HPV actually exists in the tissue of the cervical carcinoma and that there is a close relationship between the cervical carcinoma and HPV infection. This experiment adopted the Biotin-labelled HPV 16 DNA probe. And it may provide us with a quick and sensitive method for investigation of the infection of HPV and its role in the carcinogenesis of cervical carcinoma.

Biotin↗
PubMedDate not supplied

Lack of secondary hyperalgesia and central sensitization in an acute sheep model.

BACKGROUND AND OBJECTIVES: We aimed to determine the following in an experimental acute pain model in sheep: (1) whether multimodal analgesia with intravenous fentanyl and ketorolac was more effective than fentanyl alone; (2) whether secondary hyperalgesia (central sensitization) occurred in adjacent (foreleg) dermatomes after thoracic surgery; (3) whether ketorolac used preemptively influenced the development of secondary hyperalgesia after surgery. METHODS: Changes in primary nociception were measured by increases to tolerated pressure, applied to the foreleg by a blunt pin, before foreleg withdrawal occurred. Changes to breath-to-breath interval and estimated end-tidal CO2 were used as indices of respiratory effects. Study 1 (n = 6) compared the paired responses to acute nociception after ketorolac (90 mg) or saline (control) pretreatment, followed by fentanyl (graded, 0 mg to 1.5 mg). Study 2 (n = 6) used a cross-over of ketorolac (90 mg) or saline (control) 24 hours and 1 hour, respectively, before a standardized thoracotomy incision, followed by antinociceptive testing with ketorolac (90 mg) and fentanyl (0.6 mg) daily over 4 days. RESULTS: In study 1, fentanyl produced naloxone-antagonizable antinociception and respiratory depression. Ketorolac did not affect fentanyl antinociception, except for prolonging antinociception at the highest dose; it did not affect the respiratory effects. In study 2, preemptive ketorolac had no effect on the postoperative antinociceptive or respiratory effects of fentanyl. The pharmacokinetics of fentanyl were unaltered by ketorolac. CONCLUSIONS: The results obtained in this acute pain model found no significant evidence of a fentanyl-ketorolac interaction, of central sensitization as shown by secondary hyperalgesia, or of a preemptive analgesic effect.

Acute Disease↗
PubMedDate not supplied

Kimura's disease in a teenage male: report of one case.

A 14-year-old boy gradually developed several subcutaneous masses over bilateral peri-auricular regions, neck, and both upper arms near the elbows over the past 2 years. The recent development of eyelid puffiness elicited his seeking medical attention. Hypereosinophilic syndrome was first considered due to the markedly elevated blood eosinophil count without other evidence of allergy or parasite infestation, but the absence of organ involvement made this diagnosis questionable. The histopathological investigation of the subcutaneous mass in the upper arm showed lymph node-like tissue with markedly reactive follicular hyperplasia and eosinophilic abscesses associated with granulomatous inflammation, thus leading to the final diagnosis of Kimura's disease. Oral prednisolone was prescribed successfully. This illness occurs mainly in young oriental males. We report this case to introduce it to pediatric clinicians as an important differential diagnostic entity in eosinophilia-associated diseases and reactive lymphadenopathy.

Adolescent↗
PubMedDate not supplied

The predisposing factors of coagulase negative staphylococcal bacteraemia in neonatal intensive care unit.

Coagulase negative staphylococci are the commonest blood culture isolate from infants on neonatal intensive care units. The differentiation of contaminants from isolates representing true infection remains a significant clinical problem. Data from two neonatal intensive care units were collected prospectively in order to find those parameters, which best correlated with actual sepsis. Each case was assessed using clinical parameters to categorise infants into infection and contaminant groups. Logistic regression was then performed to find significant correlates. Three correlates were found, namely the presence of a long line (P = 0.001), abnormal white cell count (P = 0.037) and abnormal white cell morphology (P = 0.027). Abnormal white cell morphology was assessed by two experienced hematologists. More than half the isolates were probable contaminants and true infection may occur in the absence of a long line in this patient group.

Adrenal Cortex Hormones↗
PubMedDate not supplied

A total organic carbon analysis method for validating cleaning between products in biopharmaceutical manufacturing.

The validation of cleaning procedures for biopharmaceutical products produced by recombinant DNA (rDNA) technology presents a diverse analytical challenge. This is because of the need for quantitation of a broad range of potential residual cellular components, including proteins, carbohydrates, and nucleic acids, as well as trace levels of detergents at various manufacturing stages. The validation of a Total Organic Carbon (TOC) analysis method for use in cleaning validation studies is presented. The method has a limit of detection of approximately 0.1 ppm, with a limit of quantitation of 0.5 ppm. TOC analysis has an accuracy of 50 to 70% or better in the 0.5- to 10-ppm range and demonstrates an overall variability of approximately 5%. The method is broadly applicable to a variety of impurities and contaminants that are likely to be encountered following the manufacture of rDNA products.

Asepsis↗
PubMedDate not supplied

Torticollis: a long-term follow-up study.

To achieve better guidelines for the future management of torticollis, this study analyzed surgical and nonsurgical management of 253 torticollis patients who were treated in this hospital from 1971 to 1993. Of those, 37 cases received operation only, 78 cases were operated after failed physical therapy, and 138 cases were treated only at the Rehabilitation Department. If free neck movement was considered to be the primary goal of treatment, most parents were satisfied with the results. However, if facial and skull deformities were the serious sequelae of torticollis, then only less than half of the surgical and nonsurgical groups of patients were graded as normal. Further, 10.9% of physical therapy group and 7% of the surgical patients need further operation to release the fibrotic bundle which limited their neck movement. Therefore, it is suggested that torticollis treatment should include early interventions such as adjusting sleep position, careful planning of physical therapy and/or operation and a long term follow-up period as essential for better management of torticollis.

Child↗