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Biomedical subjects

H H Liu

Publications and source records attributed to H H Liu.

At least 73 records · Page 4Linked to original sources

Effect of somatotropin of mammalian cell origin in growth hormone deficiency.

Sixty-nine growth hormone-deficient patients were treated for 1 year with somatotropin (recombinant DNA-derived human growth hormone) produced in mouse cells. The growth velocity of the 50 patients (72%) in whom the effectiveness of this growth hormone could be evaluated increased from a mean (+/- SD) of 3.5 +/- 1.1 to 8.7 +/- 1.6. cm/y. An enhanced rate of weight gain was also observed. Bone age was not unduly accelerated. One of 66 patients developed antibodies to recombinant growth hormone, which did not affect the response to therapy. No patient developed antibodies to host cell proteins. An increased insulin response to a standard glucose load, without any change in glucose tolerance, was observed after 1 year of treatment. This authentic sequence human growth hormone preparation produced in mammalian cells is both effective and safe in the treatment of children with growth hormone deficiency.

Adolescent↗

[Application of the "Wits" approsal in Shanghai children with normal mixed or early permanent dentition]

128 children in Shanghai with normal mixed or early permanent dentition were selected in this servey to gain their normal value of the "wits" approsal.The results showed (1) there was no significant difference of "wits" approsal between the two groups of the children. (2)There was no disparity in "wits" approsal ofthe children with the same nationality and living in different regions. (3) There was a little change in value of the "wits" apporsal during the growth period or the children,which indicated a comparative identical relationship between the upper and lower basal bone.This study suggested that the application of the "wits" approsal be very imnportant in orthodontic clinic because of its expressing exactly the relationship of the jaws.

Journal Article↗

[The effect of EBCI Iontophoresis on orthodontic tooth movement in rabbits]

The purpose of this study was to observe the effect of EBC ionophoresis on increasing the rate of tooth movement in rabbits.21 rabbits,in whose lower incisors the standard orthodontic appliances were placed,were divided into 3 groups at rendom which separately received iontoporesis of EBC,iontophosesis and injection of physiological saline at the submucosal area of the lower incisors.The results showed that the animals with EBC iontophoresis obtained tooth movement rate of 4.275+/-0.1214(mm) and the animals with NaCl iontophoresis and injection were respectively 3.337+/-0.4626(mm) and 2.178+/-0.2922(mm).The histological observation had also found the evidence of the ability of EBC to stimulate osteoclasts in preiodontal pression side and osteoblasts in tension.This study suggested that iontophoresis of EBC could play an important role in reconstructing the periodontum and speeding the tooth movement in rabbits.

Journal Article↗

Development of cholinesterase histochemical staining in cerebellar cortex: transient expression of "nonspecific" cholinesterase in Purkinje cells of the nodulus and uvula.

Patterns of "nonspecific" cholinesterase (ChE) and acetylcholinesterase (AChE) activity were studied in developing rat cerebellar cortex by enzyme histochemistry and light and electron microscopy. Three types of ChE histochemical reaction product were observed in cerebellar cortex: (i) ChE is found in capillary endothelium throughout the cerebellum. Capillary ChE staining is present by the time of birth and continues into adulthood. (ii) ChE is found in radial glial fibers and their parent cell bodies, the Golgi epithelial cells. Radial glial fiber staining is mot intense during the first 3 weeks of postnatal life. (iii) ChE is found in Purkinje cells of the nodulus and ventral uvula. No ChE staining of Purkinje cells was seen in other parts of the cerebellum. ChE staining of Purkinje cells appears to be transient, first appearing at Postnatal Day 2 (P2), reaching peak intensity at P7-9, and decreasing to adult levels by P16. AChE activity displays a pattern markedly different from ChE, with staining in deep cerebellar nuclei, in putative mossy fiber terminals, and in Golgi neurons of cerebellar cortex. No evidence was found for transient AChE staining in Purkinje cells in any part of the cerebellum. The function of transiently expressed ChE activity in developing Purkinje neurons is unknown, but may be related to reorganization of cerebellar cortical circuitry associated with growth of mossy fiber afferents.

Acetylcholinesterase↗

Comparison of conventional susceptibility tests with direct detection of penicillin-binding protein 2a in borderline oxacillin-resistant strains of Staphylococcus aureus.

Six selected strains of Staphylococcus aureus classified as borderline oxacillin-resistant, according to standard disk diffusion and microdilution susceptibility test methods, and seven methicillin-resistant and seven methicillin-susceptible control strains were examined for the presence of penicillin-binding protein 2a (PBP 2a) by fluorography and immunoblotting and for DNA hybridization with a mec-specific probe in a dot blot assay. Oxacillin agar screen tests with and without NaCl supplementation were also performed with all strains. PBP 2a was detected both by fluorography and by immunoblotting in all seven methicillin-resistant control strains and in none of the susceptible controls. PBP 2a was detected in two borderline strains. Results of agar screen tests performed without NaCl supplementation were completely concordant with susceptibility determined by PBP 2a and mec detection methods. Agar screening with NaCl supplementation was less accurate. These findings were confirmed with 20 additional borderline strains. Direct detection methods for the presence of PBP 2a or mec, the gene encoding it, allow accurate and definitive classification of borderline strains. Further efforts to develop a rapid, clinically useful, antibody detection system for PBP 2a are warranted.

Animals↗

Effect of a beta-adrenergic blocking agent on dental anxiety.

The effect of propranolol was studied on 23 dental phobics in a double-blind, placebo-controlled clinical trial involving actual dental treatment. The subjects were selected because they showed high physiological reactivity in the dental situation. Twelve subjects received the test drug and 11 subjects received the placebo at individualized doses of either 80 or 120 mg. A significant difference in self-reported anxiety at the injection phase of treatment and less overall pain intensity and aversiveness were observed for the propranolol as compared with the placebo group. No differences were detected for behavior ratings. Beta-adrenergic blocking agents may have utility for reducing anxiety in individuals fearful of dental treatment.

Adolescent↗

A cross-cultural cross validation of the Dental Fear Survey in South East Asia.

This study was designed as a cross-cultural replication and cross validation of the Dental Fear Survey (DFS) in two groups of Singapore adults: university students and military conscripts. Factor analysis of the DFS in each of these dissimilar samples revealed factor structures that were highly comparable to one another as well as to those obtained in the U.S.A. Behavioral and physiological fear assessment during exposure to simulated dental treatment also showed results comparable to those found in Western cultures. Self report measures were more likely to correlate with other self reports than with physiologic or behavioral measures. Among university students, those who had visited a dentist within the past year had significantly lower DFS scores than those who had avoided dentistry. The fear-avoidance relationship did not hold for military subjects who reported less dental fear overall. It was concluded that the DFS was factorially stable; and therefore, generalizable to this South East Asia culture.

Adolescent↗

Resonance Raman enhancement of phenyl ring vibrational modes in phenyl iron complex of myoglobin.

Resonance Raman spectra are reported for the organometallic phenyl-FeIII complexes of horse heart myoglobin. We observed the resonance enhancement of the ring vibrational modes of the bound phenyl group. They were identified at 642, 996, 1,009, and 1,048 cm-1, which shift to 619, 961, 972, and 1,030 cm-1, respectively, upon phenyl 13C substitution. The lines at 642 and 996 cm-1 are assigned, respectively, as in-plane phenyl ring deformation mode (derived from benzene vibration No. 6a at 606 cm-1) and out-of-plane CH deformation (derived from benzene vibration No. 5 at 995 cm-1). The frequencies of the ring "breathing" modes at 1,009 and 1,048 cm-1 are higher than the corresponding ones in phenylalanine (at 1,004 and 1,033 cm-1) and benzene (at 992 and 1,010 cm-1), indicating that the ring C--C bonds are strengthened (or shortened) when coordinated to the heme iron. The excitation profiles of these phenyl ring modes and a porphyrin ring vibrational mode at 674 cm-1 exhibit peaks near its Soret absorption maximum at 431 nm. This appears to indicate that these phenyl ring modes may be enhanced via resonance with the Soret pi-pi transition. The FeIII--C bond stretching vibration has not been detected with excitation wavelengths in the 406.7-457.9-nm region.

Animals↗

Antibiotics and infectious diseases.

Selection of antibiotics in clinical practice has become increasingly complex because more patients have underlying predispositions to infection, a greater variety of microorganisms with varying antibiotic resistance patterns cause these infections, and more antibiotics are available to treat these pathogens. A practical approach to antibiotic decision-making involves comparing the advantages and disadvantages of each group of antibiotics available while remembering the patient population being treated and the common pathogens encountered in one's practice. It is helpful to study the penicillin derivatives in approximately chronologic order of development and the cephalosporins in terms of generations because this puts the use of each individual agent in perspective. Familiarity with commonly encountered adverse antibiotic reactions, dosage guidelines, and special situations (pregnancy, pediatric patients) will help avoid problems associated with antibiotic use. Finally, having one or more useful references at hand will aid in resolving questions about antibiotic use.

Anti-Bacterial Agents↗

Management of Pneumocystis carinii pneumonia in patients with AIDS and other conditions: experience in a Philadelphia University Teaching Hospital.

We reviewed the records of 49 patients who had 55 episodes of Pneumocystis carinii pneumonia (PCP) from January 1984 to January 1987. Thirty-three patients had acquired immunodeficiency syndrome (AIDS), with the risk groups being homosexual/bisexual practices (26), hemophilia (6), and blood transfusion (1). Fourteen patients had a history of malignancy or chemotherapy and two underwent organ transplantation. Overall response to therapy of PCP was 75% (77% of patients with AIDS, 68% of those with other conditions). All six relapses occurred in patients with AIDS. Both trimethoprim-sulfamethoxazole (TMP-SMX) and pentamidine were associated with a higher rate of toxicity in those patients than in patients with other conditions. A 30% rate of failure due to side effects occurred when TMP-SMX was used as initial therapy, but the combination is considered effective and should be given an adequate therapeutic trial. Pentamidine was an effective alternative for patients who failed with TMP-SMX and for those who failed therapy due to side effects, but was associated with serious toxicities. Our experience was similar in some respects to previous published results from New York and California.

Acquired Immunodeficiency Syndrome↗

Ultrasound thermotherapy effect on the recovery of nerve conduction in experimental compression neuropathy.

Bilateral tibial nerves of 18 albino rats were mechanically compressed between knee and ankle. Beginning on the fifth day after compression, ultrasound thermotherapy of 0.5 or 1.0watt/cm2 was applied over the area of nerve compression in one limb for one minute three times per week. The other side (control) was not treated. Motor distal latency (DL), motor nerve conduction velocity (NCV) of the segment with nerve compression, and amplitude of the evoked compound muscle action potential (ACMAP) were measured before and immediately after nerve compression and two or three times per week after compression. The recovery rates of NCV and ACMAP of the tibial nerve treated with ultrasound of 0.5watt/cm2 were significantly faster than those of the control nerve. There was no significant change in the recovery rate of DL. However, if ultrasound of 1.0watt/cm2 was applied, the recovery rate of ACMAP of the treated nerve was slower than that of the control nerve. There were no significant changes in the recovery rates of DL and NCV. Low doses of ultrasound thermotherapy may facilitate recovery of compression neuropathy, but higher doses may induce an adverse effect.

Action Potentials↗

A mutant of Streptococcus pneumoniae that exhibits thermosensitive penicillin tolerance and the paradoxical effect.

Mutants of Streptococcus pneumoniae that contain active autolysin and yet cannot be induced to lyse during treatment with penicillin (Lyt+Tol+ mutants) have been described. We have now shown that these mutants are temperature dependent (32 degrees C); at 37 degrees C these bacteria underwent penicillin-induced lysis. In addition, mutants at the lysis-permissive temperature showed the so-called 'paradoxical response' to penicillin. Temperature shift experiments indicated that the change from tolerant to lytic response or vice versa is a fast process. No differences were detected in autolysin specific activity or in the kinetics of inhibition of protein, peptidoglycan and teichoic acid syntheses in cells treated with penicillin at 32 and 37 degrees C. The results of genetic crosses indicated that the thermosensitivity of penicillin-induced autolysis in the Lyt+Tol+ mutants is not a property of the autolytic enzyme itself. The observations suggest that the thermosensitive process in the mutants represents either a step(s) in autolysin regulation or involves some difference in the structure of the cell walls produced at 32 degrees C versus 37 degrees C.

Bacteriolysis↗