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Biomedical subjects

S C Wang

Publications and source records attributed to S C Wang.

At least 163 records · Page 9Linked to original sources
PubMed1990

Evaluation of Gd-DTPA-labeled dextran as an intravascular MR contrast agent: imaging characteristics in normal rat tissues.

Dextran covalently linked to moieties of gadolinium diethylenetriamine pentaacetic acid (DTPA), for use as a macromolecular, intravascular blood pool marker for contrast material-enhanced magnetic resonance (MR) imaging was characterized by means of physicochemical and relaxivity measurements and MR imaging in healthy rats. Dextran labeled with 15 Gd-DTPA moities (molecular weight of approximately 75,000 d) had a T1 relaxivity at 0.25 T and 37 degrees C of 157.1 mmol-1.sec-1 per molecule and 10.5 mmol-1.sec-1 per gadolinium atom, more than twice that of unbound Gd-DTPA. Osmolality was 300-350 mOsm/kg at a gadolinium concentration of 0.01 mmol/L. Tissue enhancement was essentially linearly related to injected dose in the gadolinium dose range of 0.01-0.05 mmol/kg of body weight. Approximate typical enhancement values over baseline for normal tissues at 10 minutes after a gadolinium dose of 0.05 mmol/kg were as follows: cardiac muscle, adrenal gland, and liver, 40%-50%; lungs, 160%-200%; renal cortex, 130%; renal medulla, 240%; spleen, 75%; muscle, 15%; and brain, 5%-10%. Projection-subtraction images showed that dextran-(Gd-DTPA)15 remained intravascular for at least 1 hour after injection. The prolonged and easily appreciated levels of tissue enhancement with dextran-(Gd-DTPA)15, at a gadolinium dose less than that routinely used in Gd-DTPA, indicate further evaluation of this macromolecular marker.

Animals↗
PubMed1989

The production of polyclonal and monoclonal antibodies in mice using novel immunization methods.

Two novel immunization methods (intrasplenic and intra-inguinal lymph node) have been developed for the production of polyclonal and monoclonal antibodies in mice. Freund's complete adjuvant and antigen were mixed in the ratio of 1:2 (v/v). Various concentrations of human serum albumin (HSA) were used as antigen. No primary immune response was induced with 0.1 microgram of HSA in either of the methods studied. Intrasplenic immunization resulted in the strongest primary immune responses using all other doses of HSA. The primary immune response induced by intrasplenic immunization with 0.5 microgram of HSA was higher than any response induced by subcutaneous immunization with various doses of HSA. Inguinal lymph node immunization was less effective than intrasplenic immunization but better than subcutaneous immunization with 1-50 micrograms of HSA. Comparisons were also made of the efficacy of different adjuvants when inducing primary immune responses with 1 microgram of HSA. Freund's complete adjuvant resulted in a much stronger response than Freund's incomplete adjuvant and alum. Both intrasplenic and inguinal lymph node immunization using 1-5 micrograms of HSA were able to induce strong primary immune responses. Secondary immunization with either method or intravenous injection 3 days before fusion resulted in a higher frequency of specific monoclonal antibodies.

Adjuvants, Immunologic↗
PubMed1989

A brief overview of nuclear medicine in China.

The year 1956 witnessed the birth of Nuclear Medicine in China, when the first course, Biomedical Applications of Isotopes, was offered in our country by the Peking Union Medical College (PUMC). This course was preceded by a training course in nuclear instruments in which students learned to construct the radiation detection devices required for performing experiments using radioisotopes. In 1958, several courses in clinical nuclear medicine brought up the first generation of nuclear medicine physicians in China. Historically, some of the chief events include: (1) operation of the first reactor, producing 33 radioactive isotopes in 1958; (2) first linear scanner built in 1960; (3) setting up an organization for the control of radiopharmaceuticals in 1961; (4) distribution of the first batch of cyclotron-produced isotopes in 1963; (5) development and use of the first radioimmunoassay (RIA) procedure in 1963; (6) production of tritium in 1964; (7) production of 99.8% enriched heavy water in 1965; (8) supply of 99mTc and 113mIn generators in 1972; (9) first gamma camera imported in 1972 and first homemade gamma camera installed in 1977; (10) founding of Chinese Society of Nuclear Medicine (CSNM) in 1980; (11) publication of the Chinese Journal of Nuclear Medicine beginning in 1981; (12) first single photon emission computed tomography (SPECT) imported in 1983. At present, there are 556 nuclear medicine departments in China with 4,000 staff.(ABSTRACT TRUNCATED AT 250 WORDS)

China↗
PubMed1989

Urethral dilation in the management of urological complications of myelodysplasia.

Urethral dilation was performed in 11 of 65 myelodysplastic children with high intravesical pressures. These 11 children had persistent bladder pressure elevations uncontrolled by intermittent catheterization and anticholinergic agents. After dilation intravesical pressures decreased, and upper tract function and measured bladder compliance improved. No discernible effect on continence function occurred. The procedure appears to be a safe alternative to temporary vesicostomy in myelodysplastic children with high intravesical pressures that cannot be controlled by intermittent catheterization and anticholinergic agents.

Child↗
PubMed1989

In vitro effects of cycloheximide and luteinizing hormone on the estradiol-to-progesterone shift in follicular steroidogenesis.

The objectives of this study were to establish a completely in vitro system that would simulate the in vivo effects of cycloheximide (cyclo) on preovulatory serum levels of estradiol (E2) (prolonged) and progesterone (P4) (reduced). Graafian follicles were removed from proestrous hamsters at 0900 h and incubated for a basal hour (Hour 1) with various doses of cyclo before the medium was replaced; in Hour 2, 100 ng luteinizing hormone (LH) was added with cyclo added every hour for 5 or 6 h. The endpoints were steroid levels/follicle/h per ml medium of P4, 17 alpha-hydroxyprogesterone (170HP), androstenedione (A), and E2. The goal was best accomplished with hourly addition of 400 ng cyclo, which reduced follicular protein synthesis by 76%. Cyclo suppressed P4 and 170HP and prolonged the accumulation of A and E2, in Hour 5 and Hour 6, correlated with sustained thecal C-17,20-lyase/17 alpha-hydroxylase as determined by enzyme assays. Cyclo therefore prevented the early demise of the enzyme complex after LH stimulation and hence prolonged the ability of the theca to provide androgens for conversion to E2 by the granulosa cells. Our earlier work established that one of the major effects of LH is to recruit the granulosa compartment as a source of C-21 steroids, and cyclo interferes with the availability of cholesterol to mitochondrial side-chain cleavage (Greenwald and Limback, 1984). Thus, cyclo affects follicular steroidogenesis through different mechanisms in theca and granulosa.

17-alpha-Hydroxyprogesterone↗
PubMed1988

A bladder pressure management system for myelodysplasia--clinical outcome.

A program for the management of neurogenic bladder in patients with myelodysplasia was instituted in July 1983. Of the 114 patients entered into the program who have been followed for a minimum of 18 months 42 per cent required treatment for high intravesical pressures. None of this group or the larger group with low bladder pressures showed progressive upper urinary tract deterioration. In 8 children (17 per cent of those with high pressure bladder dysfunction) high intravesical pressure persisted despite anticholinergic medication and intermittent catheterization, and they required an operation to achieve a low pressure bladder. These results confirm the findings in other studies that about 40 per cent of myelodysplastic children are at high risk for the development of upper tract changes, and that approximately 6 to 8 per cent will not respond sufficiently to anticholinergic agents and intermittent catheterization.

Adolescent↗
PubMed1988

Fascial sling to correct male neurogenic sphincter incompetence: the McGuire/Raz approach.

We report the surgical approach used in 4 male myelomeningocele patients suffering from severe urinary incontinence owing to poor bladder compliance and sphincter incompetence. While bladder compliance was corrected by enlargement cystoplasty the sphincteric incompetence was treated by an autologous fascial sling around the bladder neck with excellent results. We consider this operation as an alternative to the artificial urinary sphincter in cases of male neurogenic sphincter incontinence.

Adolescent↗
PubMed1987

Indium-111 chloride imaging with ununited fractures.

Twenty patients with ununited fractures and a suspicion of infection had In-111 chloride imaging. Surgically obtained cultures were positive for infection in 12 and negative in eight patients. In-111 chloride images were positive in all 12 patients with infection but also were positive in six of the patients with negative cultures. It is not possible to differentiate infected from noninfected ununited fractures by In-111 chloride imaging.

Fractures, Ununited↗