Search PubMed⌕ Search

Biomedical subjects

S H Li

Publications and source records attributed to S H Li.

At least 127 records · Page 7Linked to original sources
PubMed1992

The effect of a deprogrammer on the position of the terminal transverse horizontal axis of the mandible.

This study measured the amount of positional change in the terminal transverse horizontal axis of the mandible that results from altering undesirable neuromuscular influence. Centric relation records were made on 19 healthy subjects before and after deprogramming. The axis was located with a computerized axiograph, and the centric relation records were compared in vivo at the axis location. The positional change of the axis was quantified in three dimensions at an accuracy of +/- 0.05 mm. The net amount of positional change was compared to scores from the temporomandibular joint scale to test for correlation with the potential for developing a temporomandibular disorder. The findings showed that the amount of positional change in the terminal transverse horizontal axis in 18 of 19 healthy patients after 12 hours of deprogramming was less than 0.5 mm and did not correlate with scores from the TMJ Scale.

Adolescent↗
PubMed1992

Effects of a single oral dose of desipramine on postoperative morphine analgesia.

Drugs that block norepinephrine reuptake offer promise as opioid potentiators, because norepinephrine mediates opioid analgesia but not side effects such as sedation or nausea. In a two-by-two factorial design, we randomized 62 inpatients with pain following major surgery to receive either desipramine, 50 mg by mouth, or placebo at 6 a.m. on the first day after surgery. At their first request of pain medication after 8 a.m., they were given intravenous morphine, either 0.033 mg/kg or 0.10 mg/kg. Pain relief and side effects were assessed for 4 hr; peak relief on the visual analog scale (VAS) was the primary outcome variable. Pain relief, side effect scores, and time to remedication were significantly greater with the higher dose than with the lower dose of morphine, verifying assay sensitivity, but desipramine pretreatment did not significantly enhance morphine analgesia. The mean increase in peak VAS relief score after desipramine pretreatment, relative to placebo, was 6%; the 95% confidence interval for this estimate ranged from a 21% reduction to a 34% increase in pain relief. These results differ from a previous report that 1 week of pretreatment with desipramine, 75 mg per day, potentiated postoperative morphine analgesia. We conclude that if desipramine potentiation of opioid analgesia occurs in humans, its demonstration may require higher doses or chronic treatment.

Administration, Oral↗
PubMed1992

Synergistic effects of interleukin 4 and interferon-gamma on monocyte phosphodiesterase activity.

Patients with atopic dermatitis (AD) have elevated leukocyte cyclic AMP-phosphodiesterase (PDE) activity and increased in vitro IgE synthesis compared to normal (NL) subjects. Interleukin 4 (IL-4), interferon-gamma (IFN-gamma), and PDE inhibitor have been shown to regulate in vitro IgE synthesis. This study investigated whether soluble T-cell factors such as IL-4 and IFN-gamma could account for elevated PDE activity in patients with AD. Both rhIL-4 and IFN-gamma significantly increased normal monocyte PDE activity to a maximum of 188% (n = 6, p less than 0.05) and 315% above control (n = 3, p less than 0.05), respectively. At concentrations below 0.1 units/ml IL-4 and IFN-gamma had synergistic effects on activation of monocyte PDE. AD and NL T-cell culture supernatants also significantly stimulated normal monocyte PDE activity, but the stimulatory activity was not significantly greater in the AD T-cell supernatants. The effect of both cytokines and T-cell supernatants on normal monocytes was inhibited by antibodies against IL-4 and IFN-gamma, respectively. This study demonstrates that IL-4 and IFN-gamma can increase PDE activity in normal monocytes. Though the levels of IL-4 and IFN-gamma in T-cell supernatants are undetectable with an enzyme-linked immunosorbent assay (ELISA) assay, the concentration of these cytokines below the detectable level can significantly increase PDE activity of monocytes in a synergistic and dose-dependent manner. These results suggest that cytokine-mediated activation of monocytes can increase PDE activity. Furthermore, lymphokines may play an important role in modulating the cyclic nucleotide regulatory pathway.

Dermatitis, Atopic↗
PubMed1992

A comparison of the caries-preventive effects of fluoride mouthrinsing, fluoride tablets, and both procedures combined: final results after eight years.

This paper presents final results of an eight-year clinical trial designed to compare the caries-preventive benefits of two self-administered fluoride procedures when used separately and in combination with one another. Children in kindergarten and first grade residing in Springfield, Ohio, a nonfluoridated community, were assigned randomly within school to one of three groups that either (a) rinsed once a week in school with a 0.2 percent neutral NaF solution; (b) chewed, rinsed with, and then swallowed daily in school a neutral 2.2 mg NaF tablet; or (c) carried out both procedures. At baseline (1981), 1,640 participants were examined clinically using the DMF surface index. Findings for 640 children remaining after eight years show that subjects in the combination group experienced a mean caries increment of 2.40 DMFS, 15.2 percent lower than the mean score of 2.83 DMFS for children in the tablet group and 32.8 percent lower than the 3.57 DMFS for those in the rinse group. Only the difference in incremental caries scores between the combined fluoride procedure and the fluoride rinse was statistically significant (P less than .05). The pattern of these findings is similar to that found on the two interim examinations. Even though the combined regimen showed an additional caries-preventive benefit compared with the rinse, considerations of cost effectiveness and feasibility do not support changing an ongoing rinse program to one that employs both procedures. For new programs the best choice appears to be the tablet procedure alone.

Adolescent↗
PubMed1992

Diurnal variation of insulin sensitivity in NIDDM patients and normal subjects.

A modified insulin suppression test was adopted to assess the diurnal variation in insulin sensitivity and insulin clearance in 14 non-insulin-dependent diabetes mellitus (NIDDM) patients and eight age-, sex- and weight-matched normal subjects. The modified insulin suppression test was combined with an infusion of regular insulin, 30 mU/min x m2; glucose, 6 mg/kg x min; and somatostatin, 500 micrograms/h, for 120 minutes followed by only a somatostatin infusion for 60 minutes. Blood samplings were performed at appropriate times to obtain data on steady-state plasma insulin (SSPI), steady-state plasma glucose (SSPG as an index of insulin sensitivity), metabolic clearance and the half disappearance time (T1/2) of insulin. Blood specimens were also obtained during SSPI for measurement of erythrocyte insulin receptor binding. Each subject took the insulin suppression test twice. One test was started at 8 am and the other at 4 pm; each test was preceded by 16 hours of fasting. The order of the insulin suppression tests in each subject was randomized and balanced. In normal subjects, the SSPG level was lower in the morning than in the afternoon (118.0 +/- 43.6 vs 150.3 +/- 34.2 mg/dL, p less than 0.05). The NIDDM patients had a higher SSPG in the morning (217.7 +/- 51.4 vs 188.3 +/- 40.6 mg/dL, p less than 0.01). There was no diurnal difference in insulin clearance or the T1/2 in either normal subjects or NIDDM patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The ovarian innervation in the dog: a preliminary study for the base for electro-acupuncture.

The origin of the canine ovarian sensory and sympathetic nerves was studied by applying horseradish peroxidase (HRP) or wheat germ agglutinin conjugated to HRP (WGA-HRP) to the ovarian stroma and into the ovarian bursa. HRP/WGA-HRP positive neurons were found bilaterally in the dorsal root ganglia of T10 to L4 segment with the majority located in T13 to L2. In sympathetic paravertebral ganglia, labeled neurons were distributed bilaterally in ganglia from T11 to L4 with the majorities located in segments T13 to L2. Both distributions show ipsilateral predominance. Labeled prevertebral neurons were mainly located in the aorticorenal ganglion, ovarian ganglia and caudal mesenteric ganglion. No labeled neurons were found in the dorsal motor nucleus of vagus, nodose ganglia or sacral segment from S1 to S3. This study provides the possible morphological basis of electro-acupuncture concerning the somato-visceral reflex of the ovary.

Animals↗
PubMed1991

Bulimia nervosa. Its effect on salivary chemistry.

Erosion of the dental hard tissues and enlarged parotid and submandibular saliva glands are commonly associated with bulimia nervosa. In 15 patients and controls, no significant difference was detected in the concentrations of potassium, chloride, calcium, urea nitrogen or albumin. There was also no evidence of olfactory dysfunction.

Adult↗
PubMed1991

Effectiveness of halothane used with ultrasonic or hand instrumentation to remove gutta-percha from the root canal.

This study compared halothane and chloroform used with hand or ultrasonic instrumentation to remove gutta-percha and sealer from root canals. Apically extruded debris, residual debris, time for filling removal, and amount of solvent used were determined. The differences in extruded apical debris and radiographically visible residual debris were not significant (p greater than 0.05). Ultrasonic instrumentation required significantly less time to remove the root canal filling than did hand instrumentation (p = 0.02). The only significant difference in the amount of solvent used occurred when the ultrasonic-chloroform group was compared with the hand instrumentation-chloroform group (p = 0.05). Halothane was found to be an acceptable alternative to chloroform for removing gutta-percha and sealer from the obturated root canal.

Analysis of Variance↗
PubMed1991

Effect of three sterilization techniques on finger pluggers.

The effects of different sterilization methods on the fatigue life of finger pluggers were investigated. Ninety finger pluggers for each of four sizes (A, B, C, and D) were subdivided into subgroups of 10. Each subgroup was subjected to 1, 8, or 15 cycles of steam autoclave, dry heat, or bead sterilization. Ten control pluggers for each size were not sterilized. After sterilization, experimental and control finger pluggers were subjected to cyclic bending until fracture. Only the A finger pluggers autoclaved for eight cycles had a significantly lower number of cycles to failure compared with that of the controls. Nine subgroups had significantly greater number of cycles before failure than did the control. Because all but one sterilized group had fatigue lifetimes statistically equal to or greater than nonsterilized controls, clinicians generally can use any of the three sterilization methods without fear of plugger failure.

Analysis of Variance↗
PubMed1991

Ultraviolet response of CaF2:Tm with high-temperature treatment.

The thermoluminescent (TL) response to ultraviolet irradiation of CaF2:Tm phosphor is affected by pre-irradiation high-temperature treatment. The experimental results indicate that the maximum intrinsic TL output is about 2000 times higher for 1000 degrees C treatment than when not treated. TL stability for this phosphor occurs when the optimum temperature range and time are 800 degrees to 900 degrees C and 1 h. However, the intrinsic sensitivity is only about 50 times higher than with no treatment, which limits the application of this phosphor as a personal UV dosimeter.

Calcium Fluoride↗
PubMed1991

Effects of an acidic calcium phosphate solution and the intraoral fluoride-releasing device on dental caries and fluoride uptake in rats.

This investigation comprised two studies evaluating the effects of an acidic calcium phosphate solution (CPS) on fluoride uptake in the enamel, glycolysis of dental plaque, the incidence of dental caries and urinary fluoride concentrations of rats wearing an intraoral fluoride-releasing device (IFRD). In the first study, CPS-fluoride treatment preceded the cariogenic challenge. In the second study, the cariogenic challenge preceded the treatments. In the first study, CPS treatments increased the ability of enamel to bind fluoride. However, the enamel-bound fluoride exerted a negligible effect on plaque glycolysis as measured by the pH decrease after sucrose challenge. In the second study CPS augmented the caries inhibition for both the sulcal-morsal and buccal-lingual surfaces. In both studies the IFRD significantly restricted the development of carious enamel on the sulcal-morsal surfaces and caused elevated concentrations of fluoride in the urine independent of CPS treatments.

Actinomyces viscosus↗
PubMed1991

Further investigation on nuclear transplantation in different orders of teleost: the combination of the nucleus of Tilapia (Oreochromis nilotica) and the cytoplasm of Loach (Paramisgurnus dabryanus).

The nucleus of a blastula cell from Tilapia (Oreochromis nilotica, family Cichlidae, order Perciformes) was transplanted into an enucleated egg of Loach (Paramisgurnus dabryanus, family Cobitidae, order Cypriniformes). From among 3747 nucleo-cytoplasmic hybrid (NCH) eggs two NCH larval fish (0.05%) were obtained; one died on the 6th day and the other died on the 12th day after the operation. Morphological examinations showed that both NCH larval fish had developed normally with an opened mouth except they could not take food after complete utilization of their egg yolk on the 5th day of development. The possible mechanisms for obtaining such inter-order NCH larval fish are discussed. This is the first report indicating that inter-order NCH larval fish can be obtained in spite of their evolutionary divergence.

Animals↗
PubMed1991

Effects of platelet-activating factor antagonist SRI 63-441 on endotoxin-induced changes in rat mesenteric microcirculation.

Intravenous injection of E. coli endotoxin 30 mg/kg to rats resulted in a systemic hypotension and rapid decrease in mesenteric arteriolar blood flow velocity (MABFV). The mesenteric arterioles constricted within 3 min followed by a short period of vasodilation after endotoxin administration. Pretreatment with the platelet-activating factor receptor antagonist SRI 63-441 attenuated the endotoxin-induced systemic hypotension and the decrease in MABFV, and abolished the mesenteric vasodilation effect of endotoxin infusion. The results suggest that PAF may be a mediator of endotoxic shock.

Animals↗
PubMed1990

Phospholipase A2-induced lung edema and its mechanism in isolated perfused guinea pig lung.

Lung injury induced by phospholipase A2 (PLA2, 0.046 IU/ml perfusate) was studied in a continuous weighing system of isolated perfused guinea pig lungs. The results revealed that lung weight increased progressively during the 30-min perfusion of PLA2. No change of pulmonary arterial pressure was observed in the same period. Albumin permeability-surface area product, lung index, lung water content, exudate from pleura, and angiotensin-converting-enzyme activity increased significantly at the end of 30 min PLA2 perfusion. p-Bromophenacyl bromide, a PLA2 inhibitor, may block the above changes nearly completely. The effects of inhibitors of cyclooxygenase (indomethacin, IM), lipoxygenase (diethylcarbamaxine, DE), and platelet-activating factor (SRI 63-441) on PLA2-induced lung injury were also studied. We found: (1) PLA2 may induce high permeability lung edema. The role of endothelial injury in the permeability change remains to be further investigated. (2) DE ameliorated lung injury significantly within 10 min of PLA2 treatment but showed no effect after 15 min. IM ameliorated lung injury during the whole experimental period. SRI 63-441 had no effect. It is suggested that PLA2 may damage lung by inducing products of cyclooxygenase and lipoxygenase besides its direct effect.

Acetylcholinesterase↗
PubMed1990

Thymopentin therapy reduces the clinical severity of atopic dermatitis.

One hundred patients with moderate to severe atopic dermatitis were entered into a two-center, double-blind trial. Patients were randomized to receive either thymopentin (Timunox, n = 48) or placebo (n = 52), administered as daily subcutaneous injections for 6 weeks. Clinical extent of disease and severity parameters were measured at baseline and at regular time intervals during the study. Both the placebo- and thymopentin-treated groups demonstrated a progressive and statistically significant (p less than 0.001) decline in the overall severity of their disease, but reduction in the clinical severity score was higher in the thymopentin-treated group and statistically significant (p = 0.04) in comparison with the placebo-treated group after 6 weeks of treatment. Of the individual symptoms comprising the total severity score, pruritus (p = 0.02) and erythema (p = 0.04) were reduced significantly when thymopentin therapy was compared to placebo therapy. In addition, both the extent of body involvement and severity index (a combined severity/extent index) were significantly reduced after 6 weeks in the thymopentin-treated group in comparison to the placebo-treated group (p = 0.04). There were no serious adverse experiences in either treatment group. We conclude that treatment with thymopentin is safe and offers significant therapeutic promise for atopic dermatitis.

Adolescent↗
PubMed1990

Manganese activation of CaSO4:Dy.

The influence of Mn activation on CaSO4:Dy thermoluminescent (TL) phosphor has been observed to study the basic TL characteristics such as TL output, fading, sensitivity, and dose response. The experimental results indicate that the TL characteristics are strongly influenced by the concentration of Mn dopant in CaSO4:Dy, especially for the low temperature trapping peak of the glow curves. The TL properties of CaSO4:Dy:Mn phosphor with a concentration ratio of 1:4 of Dy to Mn include not only high sensitivity, negligible fading, and linear dose response as compared to the CaSO4:Dy phosphor, but also two well-separated peaks and relative peak heights. This suggests that it can be used for accidental dose and elapsed time evaluations as well as for a routine personnel dosimeter. It was also found that 350 degrees C to 400 degrees C for 30 min is the optimum temperature and time in annealing treatment for this phosphor.

Calcium Sulfate↗
PubMed1990

Insulin insensitivity in offspring of parents with type 2 diabetes mellitus.

Measurements were made of the plasma glucose and insulin responses to a 75 g oral glucose challenge in 50 Chinese born in Taiwan, divided into two groups on the basis of family history of Type 2 diabetes. Twenty-five individuals (age 29 +/- 5 (+/- SD) years) had 2 parents with normal oral glucose tolerance, whereas at least 1 parent had Type 2 diabetes in the other 25 subjects (age 30 +/- 6 years). In addition, in vivo insulin action was estimated by determining the steady-state plasma glucose concentration during a 3-h continuous infusion of glucose, insulin, and somatostatin. Steady-state plasma glucose concentration was used as a measure of insulin-induced glucose disposal. The 50 subjects were non-obese, and of comparable gender distribution and body mass index. Plasma glucose and insulin concentrations in response to oral glucose were similar in the two groups. However, the steady-state plasma glucose concentration was significantly (p less than 0.01) higher in offspring with a family history of Type 2 diabetes when compared by two-way analysis of variance (mean +/- SE was 5.87 +/- 0.27 vs 5.12 +/- 0.32 mmol l-1). This difference was found despite a significantly (p less than 0.01) higher steady-state plasma insulin concentration during the infusion studies (0.705 +/- 0.027 vs 0.643 +/- 0.025 nmol l-1) in offspring of people with diabetes. The results support the view that resistance to insulin-stimulated glucose uptake is present in offspring of diabetic parents.

Adult↗