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Biomedical subjects

C Lu

Publications and source records attributed to C Lu.

At least 253 records · Page 14Linked to original sources
PubMed1993

[A seroepidemiological investigation on HCV infection among population in Tianjin area].

Sera from 88 hepatitis B (HB) patients and 375 cases with gynecological conditions were detected for anti-HCV antibody with ELISA. The positive rate of anti-HCV antibody in HB cases was 12.50% (11/88); in gynecological cases was 0.80% (13/375). It was confirmed that HCV infection not only existed in this area but was also associated with the type of HB. The results suggested that HCV infection might be an important factor for HB to become chronic and difficult to treat. The positive rate of anti-HCV antibody in gynecological cases was quite high, suggesting that nosocomial infection should be paid attention to. In addition to the strict disinfection of medical equipment and blood products, the screening of blood donors, defining the indications for transfusion of blood and blood products and immunizing the population at high risk with immunoglobulin were recommended.

Adolescent↗
PubMed1993

Experimental and clinical investigations of human insoluble bone matrix gelatin. A report of 24 cases.

Human bone matrix gelatin (hBMG) was implanted into the quadriceps muscles of mice to determine its osteoinductive activity and immune responses. The host mouse muscle assay reacted positively to the hBMG, providing an experimental basis for clinical application. At two weeks after implantation, cartilage was produced in the mouse muscle, and new bone and bone marrow were formed at three to four weeks after implantation. Human bone matrix gelatin, which was thus shown to have osteoinductive activity, was subsequently implanted in 24 patients. Generally, the bone defects were filled with new bone tissue with increased density within two to four months after operation. Nonunion and delayed unions were healed at two to six months after surgery.

Adult↗
PubMed1992

Activity of the Hsp70 chaperone complex--DnaK, DnaJ, and GrpE--in initiating phage lambda DNA replication by sequestering and releasing lambda P protein.

Initiation of DNA replication by phage lambda requires the ordered assembly and disassembly of a specialized nucleoprotein structure at the origin of replication. In the disassembly pathway, a set of Escherichia coli heat shock proteins termed the Hsp70 complex--DnaK, DnaJ, and GrpE--act with ATP to release lambda P protein from the nucleo-protein complex, freeing the DnaB helicase for its DNA-unwinding reaction. To investigate the mechanism of the release reaction, we have examined the interaction between P and the three heat shock proteins by glycerol gradient sedimentation and gel electrophoresis. We have discovered an ATP-dependent ternary interaction between P, DnaK, and DnaJ; this P.DnaK.DnaJ complex is dissociated by GrpE. We have concluded that the function of the Hsp70 complex in sequestering and releasing P protein provides for the critical step in the disassembly pathway. Based on our data and other work on protein folding, the formation of the P.DnaK.DnaJ complex might involve a conformational shift to a folding intermediate of P.

Bacterial Proteins↗
PubMed1992

Activity of the purified mutagenesis proteins UmuC, UmuD', and RecA in replicative bypass of an abasic DNA lesion by DNA polymerase III.

The introduction of a replication-inhibiting lesion into the DNA of Escherichia coli generates the induced, multigene SOS response. One component of the SOS response is a marked increase in mutation rate, dependent on RecA protein and the induced mutagenesis proteins UmuC and UmuD. A variety of previous indirect approaches have indicated that SOS mutagenesis results from replicative bypass of the DNA lesion by DNA polymerase III (pol III) holoenzyme in a reaction mediated by RecA, UmuC, and a processed form of UmuD termed UmuD'. To study the biochemistry of SOS mutagenesis, we have reconstituted replicative bypass with a defined in vitro system containing purified protein and a DNA substrate with a single abasic DNA lesion. The replicative bypass reaction requires pol III, UmuC, UmuD', and RecA. The nonprocessed UmuD protein does not replace UmuD' but inhibits the bypass activity of UmuD', perhaps by sequestering UmuD' in a heterodimer. Our experiments demonstrate directly that the UmuC-UmuD' complex and RecA act to rescue an otherwise stalled pol III holoenzyme at a replication-blocking DNA lesion.

Bacterial Proteins↗
PubMed1992

Interleukin 6: a fibroblast-derived growth inhibitor of human melanoma cells from early but not advanced stages of tumor progression.

Recently we reported that human dermal fibroblasts, or conditioned media obtained from such cells, affect the growth of human melanoma cells as a direct function of tumor progression: melanoma cells obtained from early-stage (metastatically incompetent) primary lesions were growth inhibited, whereas cells obtained from more advanced (metastatically competent) primary lesions, or metastases, were growth stimulated. Ion-exchange and gel-filtration chromatography of fibroblast conditioned medium revealed the inhibitor to be a protein of molecular mass between 20 and 30 kDa and distinct from the stimulator. This is the approximate molecular mass of interleukin 6 (IL-6), a ubiquitous multifunctional cytokine known to affect in particular many kinds of hemopoietic and lymphoid cells. Since this cytokine is known to be made by fibroblasts, we attempted to determine if the human fibroblast-derived growth inhibitor (hFDGI) was identical to IL-6. Neutralizing antibodies specific for IL-6 completely eliminated the inhibitory activity of hFDGI. Moreover, exposure to human recombinant IL-6 was found to inhibit the growth of early-stage melanoma cells obtained from radial growth phase (RGP) or early vertical growth phase (VGP) primary lesions in three of four cases. In contrast, melanoma cells from a number of more advanced VGP primary lesions, or from distant metastases, were completely resistant to this IL-6-mediated growth inhibition. Acquisition of an "IL-6-resistant" phenotype by metastatically competent melanoma cell variants may provide such cells with a proliferative advantage within the dermal mesenchyme (a hallmark of melanoma cells that are malignant), helping them eventually to dominate advanced primary lesions and to establish secondary growths elsewhere.

Chromatography, High Pressure Liquid↗
PubMed1992

Successive action of DnaK, DnaJ and GroEL along the pathway of chaperone-mediated protein folding.

The main stress proteins of Escherichia coli function in an ordered protein-folding reaction. DnaK (heat-shock protein 70) recognizes the folding polypeptide as an extended chain and cooperates with DnaJ in stabilizing an intermediate conformational state lacking ordered tertiary structure. Dependent on GrpE and ATP hydrolysis, the protein is then transferred to GroEL (heat-shock protein 60) which acts catalytically in the production of the native state. This sequential mechanism of chaperone action may represent an important pathway for the folding of newly synthesized polypeptides.

Bacterial Proteins↗
PubMed1992

Verapamil (VP) improves the outcome after renal transplantation (CRT).

Calcium antagonists (CATs) have a role in the management of certain types of renal insufficiency. These include prophylaxis against post-transplant-associated acute renal failure and cyclosporine A (CsA)-induced renal dysfunction. For the transplanted kidney, CATs may be beneficial in several settings. First, a CAT during organ procurement protects the kidney during ischemic periods. Second, CATs given perioperatively protect the kidney during reperfusion and early after transplantation. Third, CATs also offer protection against CsA nephrotoxicity.

Calcium Channel Blockers↗
PubMed1992

Optical performance of the super-reversed intraocular lens.

We compared the aniseikonia, Seidel aberrations, spot diagrams, and peripheral refractive power errors of a schematic eye with a super-reversed intraocular lens (IOL) and with conventional IOLs. The results did not indicate that the super-reversed IOL performs better optically than the other IOLs, primarily because of its poorer on-axis image performance. However, this disadvantage can be overcome by aspherizing the super-reversed IOL.

Aniseikonia↗
PubMed1992

Intraoperative albumin administration affects the outcome of cadaver renal transplantation.

The prognostic significance of early malfunction or delayed function after cadaveric renal transplantation is controversial. This study examines the influence of intraoperative management in 438 cadaveric renal transplant recipients on seven posttransplant outcome measures: (1) time of onset of urine output, (2) urine volume, (3) renal function, (4) incidence of delayed function, (5) never-functioning kidney, (6) graft survival, and (7) patient survival. Delayed function, defined as the need for hemodialysis during the first posttransplant week, decreased from 46% in 1982 to 15% in 1990 and was associated with a 25% lower 1-year graft survival rate and a mortality rate of 10% at 3 months, compared with 3% when immediate function was present. The most important factors influencing the outcome were cold ischemia time (P = 0.007), intraoperative administration of albumin (P = 0.0027), duration of surgery (P = 0.020), and recipient age (P = 0.041). A high albumin dose (1.2-1.6 g/kg bodyweight) induced urine output within 30 min in 75% of patients and induced larger urine volumes (7.3 L/24 hr), as compared with the effects of a low dose (0-0.4 g/kg), which induced urine output within 30 min in 39% and only 3.7 L/24 hr. Serum creatinine at 1 week was 3.4 and 5.8 mg/dl for the high and low albumin doses, respectively (P less than 0.0001). Similarly, mean glomerular filtration rates at 1 and 7 days were 33 and 21 ml/min, compared with 47 and 28 ml/min, for the high and low albumin doses, respectively (P less than 0.01). The incidence of delayed function and of never-functioning kidneys declined from 34% and 9% for the low dose to 12% and 1% for the high dose, respectively. Finally, with increasing albumin dose, the graft survival rate at 1 year improved from 59 to 78% (P less than 0.002), and the patient mortality rate at 3 months dropped from 6% to 2%. For albumin dose intervals between the high (1.2-1.6 g/kg) and low (0-0.4 g/kg), the effect on all seven outcome measures was intermediate, generally describing a linear relationship. Weighted least-squares analysis of the relationship of delayed function with high vs. low doses of albumin, mannitol, furosemide, and volumes of crystalloid solutions showed significance only for the albumin effect. High-dose albumin infusion likely produces intravascular volume expansion and achieves a prompt restoration of blood flow, minimizes hypoxic injury, and helps preserve renal tissue. The possibility of other beneficial effects of albumin unrelated to intravascular volume also exists.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

[Preparation of antigen and antibody against aflatoxin B1].

Carboxymethyloxime of aflatoxin B1 (AFB1) was synthesized by refluxing AF B1 with carboxymethoxylamine hemihydrochloride for 4 hours in the presence of pyridine. AF B1-BSA (antigen) was made successfully by coupling AF B1-oxime with bovine serum albumin (BSA) in the presence of a water soluble carbodiimide. The rabbits were immunized with the artificial immunogen which had been purified by dialysis. The titers of antisera were determined by indirect enzyme-linked immunosorbent assay (ELISA) which was developed by ourselves. The highest titer was 1:100,000.

Aflatoxin B1↗
PubMed1992

[Observation on the changes in the frequency of end-plate potentials evoked by sera with different antibodies from patients with myasthenia gravis in nerve-muscle preparation of rats].

Using glass microelectrode recording the effect of sera with presynaptic membrane (PrM) antibody and acetylcholine receptor (AchR) antibody on the frequency of miniature end-plate potentials (MEPPs) was tested in the phrenic nerve-diaphragm preparation of rats. Sera from 5 health control persons did not affect the MEPP frequency. Twenty tested patient sera were identified to include 3 cases with AChR antibody, 6 cases with PrM antibody, 5 cases with both and 6 cases without both antibodies. The results showed that 2 cases with PrM antibody first increased for 1 to 2 minutes and then decreased the MEPP frequency. The MEPP frequency was decreased in total 11 cases, including 2 cases with AChR antibody, 3 cases with PrM antibody, 4 cases with both and 2 cases without both antibodies. The MEPP frequency was not changed in total 7 cases, including 4 cases without both antibodies and 1 case from each other 3 kinds of sera. The results demonstrated that serum from some patients with myasthenia gravis, especially from those with PrM antibody has some factors which act on the motor presynaptic ending.

Adult↗
PubMed1992

[The effect of acupuncture on rabbits with fever caused by endotoxin].

Forty-eight rabbits were used to investigate the effect of puncturing GV14, LI11 on the change of temperature and the level of plasma endotoxin. The animals were divided into 5 groups: reinforcing manipulation, reducing manipulation, electroacupuncture, endotoxin-control, N.S.-control group. The result shows that there is no influence on the fever caused by endotoxin and the level of plasma endotoxin in the treatments by the different acupuncture techniques.

Acupuncture Therapy↗
PubMed1992

Bedtime intermediate-acting insulin in the treatment of secondary failure to oral hypoglycemic agents.

Low-dose bedtime insulin therapy in combination with oral hypoglycemic agents (OHAs) has become an alternative treatment for NIDDM subjects with secondary failure to OHA. To assess its clinical efficacy, patient compliance, and its possible side effects, 33 patients with secondary OHA failure were recruited in this study. All of the subjects had experienced poor glycemic control for at least six months on their maximal OHAs before the institution of the bedtime insulin injection. Monotard HM (human insulin zinc suspension) was given at an initial dose of 0.15-0.2 U/kg body weight and was adjusted thereafter. As a whole, low-dose bedtime insulin with OHAs improved glycemic control. According to the clinical response, 10 patients (30.3%) were graded as responders, 12 (36.4%) were partial responders, 10 (30.3%) were non-responders, and one (3%) discontinued insulin therapy. There was no difference in demographic features among these three groups of patients. During this period, eight (25%) cases experienced mild hypoglycemic symptoms. In conclusion, combination of OHAs with a low-dose bedtime insulin injection is an alternative therapy for NIDDM patients with OHA failure.

Diabetes Mellitus, Type 2↗
PubMed1991

Heterogeneity of thyrotropin binding inhibitor immunoglobulins in serum from untreated patients with hyperthyroid Graves' disease.

We have previously established an assay for the simultaneous assessment of thyrotropin (TSH) binding inhibitor immunoglobulin (TBII) and thyroid stimulating autoantibody activities in cultured rat thyroid cells (FRTL-5 cell), and found a discrepancy in some patients with untreated Graves' disease between the activities of TBII measured in FRTL-5 cells (TBII-rc) and in solubilized thyroid membranes (TBII-pm). In three selected patients with untreated Graves' disease, the different dose-response relationship between TBII-rc and TBII-pm clearly indicated the heterogeneous populations of TBII-pm in patients' sera, with different binding affinities for TSH receptor in intact cells.

Animals↗
PubMed1991

Verapamil improves the outcome after cadaver renal transplantation.

Because of their favorable effects on renal hemodynamics, calcium antagonists may have a major role in the prevention and management of certain types of acute renal dysfunction. In fact, verapamil (VP) was shown to prevent cyclosporin A (CsA)-induced decreases in RBF in mice and in cadaver renal transplant (CRT) recipients. The study presented here of 59 cadaver renal transplant patients evaluates the outcome from perioperative treatment with VP (N = 30) administered intraoperatively into the renal artery (10 mg) followed by oral administration of 120 mg every 8 to 12 h for 14 days versus no drug (N = 29). Early immunosuppression included azathioprine, corticosteroids, and antilymphocyte globulin with subsequent overlapping with CsA on days 5 and 6. Actuarial graft survival at 1 yr was different when the two groups were compared (P less than 0.05). Estimated graft survival at 1 yr for VP patients was 93.3 compared with 72.4% in control patients. The improved graft survival was most striking in repeat transplants with 90% graft survival at 1 yr for VP recipients versus 37.5% for controls. Compared with controls, VP recipients had significantly improved renal parenchymal diastolic blood flow velocities on the first day after surgery (7.8 versus 5.8 cm/s). By day 7, GFR were greater with VP (44 +/- 29 mL/min) versus controls (28 +/- 22 mL/min). Of VP patients, 67% (18 of 24) had GFR greater than 30 mL/min versus 33% (9 of 26) for control patients. Similarly, on the seventh day, 77% (21 of 30) of VP patients had serum creatinines less than 2.0 mg% versus 34% (10 of 29) for controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗