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Biomedical subjects

C T Hung

Publications and source records attributed to C T Hung.

At least 91 records · Page 5Linked to original sources
PubMed1983

The analysis of tricyclic antidepressant drugs at therapeutic blood levels by reversed-phase high-performance liquid chromatography using pairing and organic counter-ions.

A serum assay method incorporating two internal standards suitable for routine clinical analysis of tricyclic antidepressant drugs at the therapeutic level is described. The method involves extraction and chromatography using a reversed-phase high-performance liquid chromatography system incorporating pairing and organic counter-ions. The quantitative characteristics of the method are reported and results are compared with consensus values for four commonly encountered drugs, amitriptyline, nortriptyline, imipramine and desipramine. The method is shown to be applicable to more recently developed antidepressants such as nomifensine and maprotiline and the flexibility of the chromatography is discussed. Sample chromatograms obtained from patient samples in the presence and absence of potentially interfering drugs and metabolites are discussed.

Journal Article↗
PubMed1982

A chromatographic quality control procedure based on HPLC for 5-hydroxymethylfurfural in autoclaved D-glucose infusion fluids.

A specific qualitative chromatographic assay method is described for 5-hydroxymethylfurfuraldehyde (5HMF) in degraded D-glucose solutions incorporating an internal standard. Comparison is made between the chromatographic method and the official direct ultraviolet absorption measurements at 284 nm for solutions of D-glucose degraded to different extents. Hospital samples of autoclaved Dextrose Injection, 5% w/v, are also examined by both methods and it is demonstrated that quite different results can be obtained depending upon the conditions of measurement. It is demonstrated that the direct absorption method does not provide an adequate limit test for compounds related to 5HMF.

Chromatography, High Pressure Liquid↗
PubMed1979

Relative vasodilator potency of ATP, ADP, AMP and adenosine (Ado) in the cat hind limb.

The relative vasodilator potencies of ATP, ADP, AMP and Ado were determined by bioassay using the skinned and unskinned cat hind limb and comparing the increase in blood flow induced by intra-arterial injection of the adenyl compounds. The relative vasodilator potencies of these agents were similar in either hind limb preparation and were as follows: ADP greater than ATP greater than Ado greater than or equal to AMP. ADP was 2-4 times more potent than ATP and about 200 times more potent than Ado or AMP. When the adenyl compounds were incubated in blood for 2 min before injection, their potencies were not changed in the bioassay. Furthermore, in a chemical assay, after Ado and ADP were incubated for 2 min in cat blood (at the concentrations used in the bioassay) only 3% of Ado and 29% of ADP were metabolized. The results indicate that ATP and ADP exert a vasodilator effect that is not dependent upon their conversion to Ado. This deduction cannot be made for AMP because its relative potency was quite similar to Ado. Since a similar relative potency was found in the skinned and the unskinned hind limb, it is concluded that the vasodilator effect due to ATP and ADP is occurring in skeletal muscle but this does not exclude simultaneous cutaneous vasodilation. The vasodilator effect of adenyl compounds may be related to purinergic receptor activation.

Adenine Nucleotides↗
PubMed1976

Predictive value of human placental lactogen determinations in pregnancy.

The relation of human placental lactogen (hPL) levels to pregnancy outcome was studied in normal and preeclamptic pregnancies, hPL determinations were performed between 38 and 44 weeks of gestation, and the results were compared with birthweight and Apgar scores in three groups. The results of hPL determinations permitted prediction of intrauterine growth retardation in all except 2 patients. The value of hPL measurement as a screening test in pregnancy is noted.

Apgar Score↗
PubMed1975

Renal carcinoma in pregnancy.

A gravid patient presented with gross hematuria in the last trimester of pregnancy but did not permit diagnostic measures. After delivery a large abdominal mass, which proved to be renal cell carcinoma, was found. Previously reported cases are reviewed, and the importance of adequate workup of hematuria during pregnancy is emphasized.

Adenocarcinoma↗
PubMed1975

Pregnancy complicated by heroin addiction.

During a 5-year time span, 118 addicted women gave birth to viable infants. These patients were subject to an increased incidence of complicating medical problems as well as many obstetric problems leading to maternal or fetal risk. The obstetrician should be aware of the possibility of addiction and its effects on pregnancy, and when possible, appropriate management should be initiated. Intensive care of the neonate must be begun as soon as possible.

Adolescent↗
PubMed1975

Comparison of sterilization by tubal ligation and hysterectomy.

A comparison was made between sterilization by hysterectomy and by tubal ligation at the time of cesarean section and as an interval procedure. All operations were done at one institution and, essentially, by the same physician population, allowing for promotion within the residency program. The major deterrent to hysterectomy was the associated high incidence of necessary blood transfusion. However, a hysterectomy does offer the benefits of a permanent and completely effective procedure and the removal of an organ which ultimately may be the source of other problems. If another pathologic condition exists, making ultimate hysterectomy likely, it is the procedure of choice for sterilization, avoiding risks, costs, and the inconvenience of another operation. Methods of elective sterilization must be individualized. If the patient is appraised of the increased risk of hysterectomy and desires this more definitive procedure on the basis of informed consent, the incidence of complications is not prohibitive. These should not deter the well trained surgeon but should mandate use of all available skills, intensive evaluation of the patient, and concerned recognition of the potential adverse consequences.

Abscess↗
PubMed1975

A diagnostic device for stress incontinence.

Many methods of evaluating anatomic deformity of the urethrovesical angle are available. A new diagnostic device has been developed to determine the degree of rotation of the urethral axis, thus differentiating between type I and type II deformities causing stress incontinence. Preliminary study in 62 patients indicates that the instrument is accurate, simple, and easily interpreted. The device also has the advantage of being easily constructed, disposable, and inexpensive.

Disposable Equipment↗
PubMedDate not supplied

Albumin microspheres. I: Physico-chemical characteristics.

Albumin microspheres are biodegradable particles which can be readily radiolabelled and synthesized in the size range of 1 to 200 microns. During the last 30 years extensive efforts have been made towards the design and development of this carrier for the purpose of diagnosis and drug delivery. This review presents a thorough discussion on the physico-chemical characteristics of albumin microspheres.

Albumins↗
PubMedDate not supplied

Albumin microspheres. II: Applications in drug delivery.

Albumin microspheres are colloidal particles which are known to sustain the release of entrapped therapeutic agent(s). The rate at which these particles metabolise in vivo can be manoeuvred by varying their synthetic conditions. These particles alter the in vivo distribution of included drugs and hence this carrier has been extensively investigated for drug delivery and targeting in laboratory animals. Attempts have also been made to use this carrier for the delivery of anti-cancer agents in patients with liver cancer. This review is focused on the experimental and clinical applications of albumin microspheres in drug delivery. An account of the toxicological properties of these particles is also presented.

Albumins↗
PubMedDate not supplied

Factorial design based optimization of the formulation of albumin microspheres containing adriamycin.

The use of factorial design in the formulation of adriamycin-associated albumin microspheres, using the heat-stabilization technique, is illustrated. The effect of stabilization temperature, protein concentration and stabilization time on the entrapment and recovery of adriamycin in microspheres have been investigated using a 2 x 4 x 4 factorial design. The associated drug content in unwashed and four times washed microspheres was determined using HPLC. Maximum drug association and drug recovery were obtained from microspheres synthesised using 25 per cent w/v albumin solution and stabilized at 120 degrees C for 2.5 min. Under these conditions, the entrapped and total associated drug content of the microspheres was about 4 per cent and 12 per cent w/w respectively, and the drug recovery was about 75 per cent. The in vitro dissolution study carried out using dynamic dialysis revealed that the release of adriamycin from these particles follows a bi-phasic pattern. The results demonstrate that use of short stabilization time, low protein concentration and low stabilization temperature are required for the formulation of microspheres with high adriamycin content.

Albumins↗