Biomedical subjects

Y Z Hu

Publications and source records attributed to Y Z Hu.

At least 19 recordsLinked to original sources

PubMed1994

Studies on the chelation of hypocrellin A with aluminium ion and the photodynamic action of the resulting complex.

Hypocrellin A (HA), a perylenoquinone derivative, is an efficient phototherapeutic agent. The chelation of HA with aluminium ion (Al3+) results in the formation of a 1:1 complex (Al(3+)-HA). The probable structure for this complex has been proposed. Compared with HA, this complex has a much higher solubility in water. In addition, Al(3+)-HA preserves the 1O2-generating function of HA as demonstrated by diphenylanthracene photo-bleaching experiments. In irradiated oxygen-saturated solutions of Al(3+)-HA superoxide radical anion and hydroxyl radical are formed as verified using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the electron spin resonance (ESR) spin trapping agent. The production of superoxide radical anion is enhanced significantly in the presence of electron donors such as 1-benzyl-1,4-dihydronicotinamide (BNAH). These results suggest that the photodynamic action of Al(3+)-HA proceeds via both type 1 and type 2 reactions.

Aluminum↗

PubMed1994

[Topical clonidine in prevention of intra-ocular hypertension after Nd: YAG laser therapy].

We evaluated the prophylactic effect of 0.25% Clonidine HCl on the increase of intraocular pressure after Nd: YAG laser therapy. IOP of 150 eyes using Clonidine and 119 eyes without Clonidine were measured before and 0.5, 1, 2, 24 hours after Nd: YAG application. Various stages of angle-closure glaucoma and after cataract were both included in the treated and control groups and were compared respectively. Overall, the incidence of increase of IOP in the Clonidine-treated group was significantly less (9.3%) than the group without Clonidine (63.0%); the incidence of marked increase (> 1.06kPa) was also significantly less (2.0%) than those without Clonidine (18.5%). The peak value of IOP after laser therapy in the treated group did not exceed 3.06 kPa. Therefore, topical Clonidine is recommended as an effective and safe procedure to prevent the intraocular hypertension in Nd: YAG laser therapy.

Adolescent↗

PubMed1993

Human plasma transport of vitamin D after its endogenous synthesis.

Transport of vitamin D3 from its sites of cutaneous synthesis into the circulation has been assumed to be via the plasma vitamin D binding protein (DBP). We studied vitamin D transport from the skin in seven healthy volunteers who received whole body irradiation with 27 mJ/cm2 dosage of ultraviolet B light (290-320 nm). Samples of venous blood were collected serially in EDTA and immediately chilled. In KBr, plasma samples were ultracentrifuged to provide a rapid separation of proteins of density < and > 1.3 g/ml. Upper and lower phases and serial fractions were analyzed for vitamin D3 (extraction, HPLC), cholesterol (enzyme assay), and human DBP (hDBP) (radial immunodiffusion). Total plasma vitamin D (basal level < 1 ng/ml) increased by 10 h and peaked at 24 h (9 +/- 1 ng/ml). 98% of the D3 remained at the density > 1.3 layers for up to 7 d, whereas cholesterol (> 85%) was detected at density < 1.3 and all of the hDBP was at density > 1.3. In three volunteers who each ingested 1.25 mg of vitamin D2, the total plasma D2 increased to 90 +/- 32 ng/ml by 4 h, and the D2 was evenly distributed between the upper and lower layers at 4, 8, and 24 h after the dose, indicating a continuing association of the vitamin with chylomicrons and lipoproteins, as well as with hDBP. Actin affinity chromatography removed D3 from plasma of irradiated subjects, indicating the association of the D3 with DBP. These findings indicate that endogenously synthesized vitamin D3 travels in plasma almost exclusively on DBP, providing for a slower hepatic delivery of the vitamin D and the more sustained increase in plasma 25-hydroxycholecalciferol observed after depot, parenteral administration of vitamin D. In contrast, the association of orally administered vitamin D with chylomicrons and lipoproteins allows for receptor-mediated, rapid hepatic delivery of vitamin D, and the reported rapid but less-sustained increases in plasma 25-hydroxycholecalciferol.

Adult↗

PubMed1993

[Combination therapy of 91 cases of spinal metastases].

The majority of spinal neoplasms are metastatic lesions. This paper reports results of combination therapy of ninety-one cases of spinal metastasis verified by pathology. Most of them were metastases from breast, lung, thyroid and gastrointestinal cancers. Multiple metastatic lesions were mainly treated by chemotherapy. Radiotherapy was for radio-sensitive solitary lesions. Indication for operation included: (1) isolated spinal focus with unknown site of primary tumor; (2) recurrence or aggravation of tumor after chemotherapy or radiotherapy; (3) isolated radioresistant focus; and (4) the patients having paraplegia or an instable spine. Thirty cases were mainly treated by chemotherapy, 10 by radiotherapy, and 51 by operation. After the combination therapy, 13 cases were completely free of symptoms, 44 alleviated and 11 invalid. Of the 39 cases having paraplegia, 3 had complete recovery, 15 partial recovery and 21 no improvement. Of 85 cases having been followed up for 1-4 years, 51 cases (59.3%) survived for 3-11 months, 25 (29.1%) for 1-2 years and 10 (11.6%) for 2-3 years. The average survival time was 10.5 months. Analyzing the clinical and radiographic manifestations of the tumors and their treatment and prognosis, we consider that early diagnosis and combination therapy are the major factors influencing the therapeutic effect of spinal metastatic tumors.

Adenocarcinoma↗

PubMed1993

[New method for selectivity optimization in thin layer chromatography and its application in pharmaceutical analysis].

A new experimental design method named the step climbing method (SCM), as well as a new global criterion (NRC), are proposed for the selectivity optimization of thin layer chromatography. The method offers chromatographers a convenient means to decide the optimum developer composition for thin layer chromatography. The principle of the method is described, and examples of applications in pharmaceutical analysis are given to certify the feasibility of the method. Clearly, it may also be used for the selectivity optimization in high performance liquid chromatography.

Cephalothin↗

PubMed1992

Identification of the sterol- and actin-binding domains of plasma vitamin D binding protein (Gc-globulin).

The mammalian plasma vitamin D binding protein (DBP), or Gc-globulin, is recognized to have at least two functional properties: sterol binding and G-actin sequestration. Affinity labeling of the sterol binding site with the radioactive electrophilic ligand, 3 beta-(bromoacetoxy)-25-hydroxycholecalciferol, followed by limited proteolysis, permitted the isolation and identification of three overlapping peptides in the amino terminus of the molecule. When G-actin affinity chromatography was applied to other proteolytic fragments, two fragments from the carboxy terminus of the molecule were isolated and identified. Another, large, tryptic fragment displayed both sterol- and actin-binding properties. The amino-terminal assignment of the sterol-binding domain was confirmed by demonstrating sterol-specific binding by an in vitro transcribed and translated product of a mutated rat DBP cDNA encoding a protein truncated in its carboxy terminus. The sterol-binding domain was localized to the region between the first-amino-terminal disulfide bond, and the actin-binding domain was found between residues 350 and 403. A high degree of sequence conservation in these regions was found among human, rat, and mouse DBP's. These functional domain assignments confirm the apparent independence of these two binding activities and help to explain the observed triprotein complex of DBP-actin-DNase I and the competition between DBP and profilin for G-actin binding. Our findings should facilitate more precise delineation of the binding domains by site-directed mutagenesis experiments.

Actins↗

PubMed1991

The IVBF dual-blade plate and its applications.

A recently developed simple device, the intervertebral body fixation dual-blade plate, was used in 88 cases of different spinal disorders. This patients in the first series were operated on from 1984 to 1986. The device is biomechanically simple and its application safe and easy. Using a proper bone grafting technique, it is a reliable device to establish spinal stability in spine surgery through an anterior approach. Its application in cases of fractures and fracture-dislocations of the thoracolumbar spine with paraplegia, tuberculous spondylitis, and primary tumors of vertebral bodies is presented. The midterm results, covering a follow-up period of 24-49 months (mean, 32 months) were satisfactory; there were no serious complications directly related to the device. There were four cases of pseudarthrosis due to insufficient bone graft technique. Of these, there were three cases of failure of the dual-blade plate.

Adult↗

PubMed1991

[Observations in vivo on spermicidal effect of nonoxynol-9 contraceptive in forms of effervescent suppository and film].

Spermicidal effect of nonoxynol-9 contraceptive in forms of efferscent suppository and film trade in China were studied in vivo. There were noticeable differences on the spermicidal effect in vivo between the two types and different doses. This study indicated that nonoxynol-9 efferscent suppository was more effective than the np-9 film in spermicidal efficacy. (1) No live sperm was found in the samples of vaginal and cervical mucus in the 20 cases of the suppository group. (2) There were live sperms in the samples of vaginal mucus of 6 cases and cervical mucus of 3 cases among the 20 cases of the film group.

Adult↗

PubMed1988

Effects of Tripterygium hypoglaucum (Lévl.) Hutch on male fertility.

Tripterygium hypoglaucum (Lévl.) Hutch (TH) is a perennial used in Chinese traditional medicine for the treatment of rheumatoid arthritis and various skin disorders. One study showed that daily oral doses of TH significantly reduced the fertility of male rats without apparent toxicity. The effects of daily oral doses of TH on the fertility of men taking it for the treatment of rheumatoid arthritis were evaluated. Sperm concentration, motility and motility grade all were significantly reduced in the 13 men taking TH compared to 11 untreated controls. TH therapy did not affect testosterone, FSH, LH levels, and its antifertility effects appeared to be reversible.

Adult↗

PubMed1988

Follow-up of men in the recovery period immediately after the cessation of gossypol treatment.

Variables in 46 men who had stopped taking gossypol in two centres in China were investigated for their predictive association with the degree and time of recovery of spermatogenesis. Thirty-nine (87%) were azoospermic at cessation of gossypol treatment. In those with sperm present the geometric mean concentration and total sperm count were 8.3 x 10(6)/ml and 30.7 x 10(6), respectively. Twenty-eight (61%) recovered to a defined threshold spermatogenic function (sperm concentration greater than or equal to 20 x 10(6)/ml), with median recovery time 1.1 years. However, 18 men (39%) had not recovered after a median follow-up of 1.9 years and, of these, 10 (22%) remained azoospermic. The failure of recovery was strongly associated with longer treatment, greater total dose of gossypol, smaller testicular volume, elevated FSH concentrations and, to a lesser extent, with greater body weight.

Contraceptive Agents, Male↗

PubMed1988

Recovery of sperm production following the cessation of gossypol treatment: a two-centre study in China.

A number of variables were investigated in 46 men who had stopped taking gossypol for their predictive association with the degree and time of recovery of spermatogenesis. Thirty-nine (87%) of the men were azoospermic at cessation of gossypol treatment. In those with sperm present the geometric mean concentration and total sperm count were 8.3 X 10(6)/ml and 30.7 X 10(6), respectively. Twenty-eight men (61%) recovered to a defined threshold of spermatogenic function (sperm concentration greater than or equal to 20 X 10(6)/ml), with a median recovery time of 1.1 years. However, 18 men (39%) had not recovered to this degree of spermatogenic function after a median follow-up of 1.9 years and, of these, 10 (22%) remained azoospermic. The influence of individual baseline variables on the time to defined recovery was examined using Kaplan-Meier curves for groups and their joint effect by Cox's regression model. The failure of recovery was strongly associated with longer treatment, greater total dose of gossypol, smaller testicular volume, elevated FSH concentrations and, to a lesser extent, with greater body weight.

China↗

PubMed1988