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Biomedical subjects

J Cao

Publications and source records attributed to J Cao.

At least 289 records · Page 16Linked to original sources
PubMed1995

Methods for the estimation of failure distributions and rates from automobile warranty data.

We consider the occurrence of warranty claims for automobiles when both age and mileage accumulation may affect failure. The presence of both age and mileage limits on warranties creates interesting problems for the analysis of failures. We propose a family of models that relates failure to time and mileage accumulation. Methods for fitting the models based on warranty data and supplementary information about mileage accumulation are presented and illustrated on some real data. The general problem of modelling failures in equipment when both time and usage are factors is discussed.

Automobiles↗
PubMed1995

The effects of low dietary copper intake during pregnancy on physiological fluids and reproductive performance of first-litter gilts.

Seven pairs of first littermate gilts were used to study the influence of low copper supply and pregnancy on physiological fluids and reproductive performance of first-litter gilts. They were fed semi-purified diets containing either 2.13 or 12.25 micrograms/kg of Cu from 30 days of gestation through two weeks of lactation. Low-Cu gilts had lower plasma Cu in early- and mid- gestation and farrowed piglets with lower plasma Cu and higher plasma Zn concentrations (p < 0.05). Plasma Fe and Mn concentrations were not affected by Cu supply (p > 0.05). Plasma Cu and Fe levels of newborn piglets were lower than those of their dams (p < 0.05) but this was not true for plasma Zn and Mn (p > 0.05). Low-Cu gilts had lower Cu and higher Zn content in colostrum and also lower Cu in milk than control gilts (p < 0.05). No significant differences were found in Fe and Mn levels in colostrum and milk between the two treatments (p > 0.05). Colostrum was richer in Cu and Zn than milk (p < 0.05) but not in Fe and Mn (p > 0.05). The low-Cu diet did not affect (p > 0.05) weight changes during pregnancy. The duration of parturition was shorter for low-Cu than for control gilts (3.19h vs. 5.71h, p < 0.05). Control gilts farrowed larger litters than low-Cu gilts (9.71 vs. 7.57 piglets, p < 0.05). There were no significant differences in live litter weights at birth, one wk. or two wks. of age (p > 0.05). The results indicated that a low-Cu diet and pregnancy had some effect on plasma, colostrum and milk mineral concentrations, as well as on litter size of gilts. An interaction between Cu and Zn was found.

Animals↗
PubMed1995

Comparative trace mineral nutritional balance of first-litter gilts under two dietary levels of copper intake.

Seven pairs of purebred Landrace first-litter gilts, housed in individual stainless-steel metabolic cages were used in this study. A low-Cu (LCu) basal diet containing only 2 mg/kg of Cu was compared to the control (CCu) diet, which was supplemented with cupric carbonate to provide 10 mg/kg of Cu. Both diets were fed at the rate of 2 kg per day to first-litter gilts during the entire pregnancy. The metabolic response under these two levels of dietary Cu intake was evaluated through nutritional balances conducted for 5 days starting at 30, 60 and 100 days of pregnancy. Total urine collection was done through teflon-coated catheters to the bladder while daily fecal collection was carried out continuously. Water consumption was measured and periodic samples were collected for analysis. Nutritional balances included DM digestibility, Cu, Zn, Fe and Mn. The LCh group consumed 4.26 mg of Cu per day while the CCu received 25 mg of Cu per day. This includes 1 mg per day in the drinking water in both groups. DM digestibility was significantly (P < 0.05) higher during early pregnancy in the LCu group compared to the CCu group, which showed a significant (P < 0.05) increase in DM digestibility from early to late pregnancy period. Dietary Cu intake had a direct effect (p < 0.05) on Cu balance but also altered the Zn and Fe nutritional balance, leaving Mn balance almost unchanged. Feces represented the almost exclusive route of excretion of trace minerals. Regardless of the dietary Cu intake, it represents more than 99.9% of the Fe and Mn, 98% of the Zn and 97% of the Cu was excreted daily through feces plus urine. The nutritional balance of Cu, Zn and Fe, in absolute amounts as well as relative to the level of intake, improved significantly as pregnancy progressed. Although relative retention of the low-Cu group was significantly improved compared to the control group, the absolute amount was still much lower. The well recognized dietary and metabolic interactions of Cu with Zn and Fe were evident in the first-litter gilts receiving the low-Cu diet during pregnancy. The absolute amount, as well as the relative retention as a % of the intake, was increased on average during the entire pregnancy for Zn by more than 70% and for Fe by more than 80% during the last third of pregnancy. In contrast Mn balance was almost unchanged. The major response to low-Cu intake was directed toward greater apparent absorption of the trace minerals which was reflected in a reduced fecal excretion.

Animals↗
PubMed1995

Ordered translocation of 987P fimbrial subunits through the outer membrane of Escherichia coli.

The 987P fimbria of enterotoxigenic Escherichia coli is a heteropolymeric structure which consists essentially of a major FasA subunit and a minor subunit, the FasG adhesin. The latter harbors the binding moiety for receptor molecules on piglet intestinal epithelial cells. In this study, anti-FasF antibody probes were developed and used to demonstrate that the FasF protein represents a new minor fimbrial component. FasF was identified in highly purified fimbriae, and its sequence demonstrated significant levels of similarity with that of FasA. Immune electron microscopy localized both the FasG and FasF proteins at the fimbrial tip as well as at broken ends and at various intervals along the fimbrial length. The presence of these minor proteins in purified 987P fimbriae was corroborated by enzyme-linked immunosorbent assay inhibitions. Finally, the use of nonfimbriated fasG, fasF, and fasA mutants indicated that subunit translocation through the outer membrane follows a specific order, FasG being the first, FasF being the second, and FasA being the third type of exported subunit. Since fimbriae are thought to grow from the base, FasG is proposed to be a tip adhesin and FasF is proposed to be a linker molecule between the adhesin and the fimbrial shaft. Moreover, export of FasG (or FasF) in the absence of FasF (or FasA) indicates that during the process of fimbrial biogenesis in the outer membrane, translocating events precede the initiation of subunit heteropolymerization.

Adhesins, Escherichia coli↗
PubMed1995

Translational inhibition by a human cytomegalovirus upstream open reading frame despite inefficient utilization of its AUG codon.

The second of three short upstream open reading frames (uORF2) in the transcript leader of the human cytomegalovirus gp48 (gpUL4) virion glycoprotein gene inhibits downstream translation approximately 10-fold. Remarkably, this inhibition depends on the amino acid coding information of uORF2. In the current studies we demonstrate that expression of the cistron downstream from uORF2 depends on ribosomes bypassing the uORF2 AUG codon (AUG2) by a leaky scanning mechanism. Replacing the nucleotides surrounding the wild-type AUG2 codon with those optimal for translation initiation reduces downstream translation approximately 10-fold. Analyses of mutants in which uORF2 either overlaps or is in frame with the downstream reading frame reveal that the initiation frequency at the wild-type AUG2 codon is surprisingly low; rather, the majority of ribosomal subunits bypass the wild-type AUG2 codon because of its suboptimal context. We propose a model to explain this unprecedented example of a paradoxically strong inhibitory effect of an upstream ORF despite inefficient utilization of its initiation codon.

Base Sequence↗
PubMed1995

Identification of malignant cells in multiple myeloma bone marrow with immunoglobulin VH gene probes by fluorescent in situ hybridization and flow cytometry.

Because it has been difficult to identify and separate malignant cells in human lymphoid malignancies, we have developed a flow cytometry-based fluorescent in situ hybridization (FISH) technique using immunoglobulin (Ig) heavy chain variable region (VH) gene probes. After obtaining the specific VH gene sequence expressed by the multiple myeloma IM-9 cell line and the malignant cells in five multiple myeloma patients, sense and antisense biotinylated single-stranded RNA probes were prepared by transcription from the malignant clone's VH DNA sequences. The cells from the IM-9 cell line and from the mononuclear bone marrow cells of multiple myeloma patients were fixed, hybridized with the above biotinylated RNA probes, incubated with streptavidin-phycoerythrin, and analyzed by FACS analysis. The myeloma cells stained positive with their own specific antisense VH biotinylated RNa probes, whereas sense and irrelevant antisense biotinylated probes demonstrated only background staining. Dilutional concentrations of the IM-9 cell line with normal bone marrow cells were also accurately quantitated by this procedure. The application of this technique will allow a more accurate assessment of tumor burden in patients with multiple myeloma and should permit an accurate method of tumor cell purification for clinical as well as biological studies. Furthermore, this technological advance should be equally effective at identifying specific VH gene-expressing cells in other lymphoid malignancies, as well as in nonmalignant B cell disorders.

Bacterial Proteins↗
PubMed1995

Longitudinal studies of blood pressure in children.

A longitudinal study of six years was conducted to find out the pattern of longitudinal changes of blood pressure and to affirm the "tracking phenomenon" of blood pressure in children in China. We initially measured blood pressure and related parameters of 2,946 children (aged 4-14 years) in 1981 at Fanshan county, Beijing, and then two follow-up remeasurements were conducted in 1985 and 1987, respectively. The results indicated that: the average level of blood pressure increases with age even after adjusting for height and weight; tracking coefficients of systolic blood pressure range from weak to moderate levels, increasing with age. Only 30% of the children whose systolic blood pressure was beyond the 90th percentile of the systolic pressure distribution at the first examination remained at the same region after four years. Multiple stepwise regression was used to determine factors correlated with blood pressure. Our results indicate that systolic blood pressure in children is correlated with body weight, pulse rate, serum glucose and HDL-C, while diastolic blood pressure is correlated only with pulse rate and serum glucose.

Adolescent↗
PubMed1995

Cellular sterol accumulation stimulated by cholesterol 5 beta,6 beta-epoxide in J774 macrophages.

A significant accumulation of cellular free cholesterol and steryl esters is observed in J774 macrophages when cells are exposed to low-density lipoproteins (LDL) containing cholesterol 5 beta,6 beta-epoxide. This cellular sterol accumulation is mainly due to the formation of esterified cholesterol and desmosterol. Cellular steryl esters increased to 39.4 and 22.4 micrograms/mg cell protein with 0.8 microM of cholesterol 5 beta,6 beta-epoxide and 3,5-cholestadien-7-one, respectively, whereas hardly detectable levels were observed with the absence of oxysterols. The total cellular sterols increased 45% above the value of control with cholesterol 5 beta,6 beta-epoxide. The uptake of [3H] cholesteryl oleate-LDL was also enhanced by cholesterol 5 beta,6 beta-epoxide. The rapid displacement of desmosterol with cholesterol was observed when cells were treated with cholesterol 5 beta,6 beta-epoxide or 3,5-cholestadien-7-one in the presence of LDL. Cholesterol 5 beta,6 beta-epoxide became associated with LDL in the culture conditions, and its uptake into J774 cells and the cytotoxicity were reduced significantly by the association with LDL. The comparison of selected oxysterols for their ability to stimulate cellular sterol accumulation indicated that cholesterol 5 beta,6 beta-epoxide is the most potent. Cholesterol esterification was enhanced significantly by cholesterol 5 beta,6 beta-epoxide whereas cholesterol 5 alpha,6 alpha-epoxide and 3,5-cholestadien-7-one produced a modest response. In contrast, although cholestantriol, the metabolic hydrolysis product of cholesterol epoxides, also associated with LDL, it showed no stimulating effect on both cellular sterol content and sterol esterification. These results indicate that some oxysterols, such as cholesterol 5 beta,6 beta-epoxide and possibly 3,5-cholestadien-7-one, stimulate cellular sterol accumulation in J774 macrophages and may play an important role in atherogenesis.

Animals↗
PubMed1995

A CD10-positive subset of malignant cells is identified in multiple myeloma using PCR with patient-specific immunoglobulin gene primers.

Immunophenotypic studies show the presence of CD10-bearing malignant cells in a small subset of multiple myeloma (MM) patients. We used a sensitive PCR-based technique in order to determine the frequency that MM patients contain a malignant subpopulation which expresses this antigen. The immunoglobulin (Ig) heavy chain variable region (VH) gene sequence expressed by the malignant clone in MM can be used as a tumor specific marker. After determining this sequence in six MM patients, patient specific VH oligonucleotide primers from complementarity determining region (CDR) sequences were generated. Bone marrow mononuclear cells from these patients were incubated with two different anti-CD10 antibodies or isotype identical murine IgG controls. Cells were then sorted by flow cytometry into the 1% brightest cells containing > 99.99% CD10-positive cells and two fractions including the 90 and 10% dimmest staining cells. PCR amplification was performed on DNA from approximately 10(4) cells (0.1 microgram) using patient specific CDR1 and CDR3 primers. Detectable PCR product was obtained in each sorted sample although the intensity of the band was much higher in cells lacking CD10 expression (the 90 and 10% dimmest fractions) than in the CD10-bearing (1% brightest) population. These results imply that there is a small population of CD10-bearing clonal cells in most, if not all patients with MM.

Base Sequence↗
PubMed1995

[Significance and detection of insulin-like growth factor I in vitreous with proliferative retinal diseases by radioimmunoassay].

The insulin-like growth factor I (IGF-I) levels in 67 vitreous samples taken from 57 patients with various proliferative retinal diseases and 10 normal subjects were detected by radioimmunoassay (RIA). The acid-ethanol-extracted (AEE) method was used to remove the IFG-binding protein before the detection. Our results revealed that IGF-I levels were increased to varying extents in these patients' vitreous. The IGF-I levels in the vitreous with proliferative diabetic retinopathy (PDR) and central retinal vein occlusion (CRVO) were significantly higher than those of the controls. In the PDR group, the increased IGF-I level in the vitreous was positively correlated with the level in serum. The increased IGF-I level in vitreous may play an important role in the development and pathogenesis of proliferative retinal diseases. Great differences were found between the native and the AEE treated vitreous, suggesting that the binding protein posed an obvious interference on the detection of IGF-I by RIA.

Adolescent↗
PubMed1995

[Onco-gene c-fos expression in light-damaged human embryo retinal pigment epithelium and protective effect of taurine and gamma-interferon].

We used well-cultured human embryo retinal pigment epithelial (RPE) cells to establish a light-damaged RPE cell model. There was no onco-gene c-fos expression in RPE cells cultured under normal condition. Immediately after 30 minutes of light exposure, onco-gene c-fos expression occurred in the RPE cells. The expression reached the highest level 1.5 hours after light exposure and disappeared 4 hours later. Taurine and gamma-interferon in different concentrations could restrain onco-gene c-fos expression in light damaged RPE cells. The restraint effects were of concentration dependence.

Cells, Cultured↗
PubMed1995

[Management of Labbé's vein in subtemporal operation].

Management of Labbé's vein in operations of cerebellar pons angle (CPA) and clivus regions was reported. Ligation of the Labbé's vein in the left side resulted in hematoma in the temporal lobe or aphasia. In preservation of Labbé's vein, either on the left or right side, only one case of intracerebral hematoma occurred. The reason for this difference was discussed. In protecting Labbé's vein, continuous ventricular draining and removal of the inferior temporal gyrus if necessary was effective.

Cerebellar Neoplasms↗
PubMed1995

[Cultured human retinal pigment epithelial cell produced and secreted epidermal growth factor: its bioactivity and clinical significance].

The epidermal growth factor bioactivity from cultured primary human and monkey retinal pigment epithelial (RPE) cell systems was detected by using the radioreceptor assay. We report that the cultured human and monkey RPE cells produce and secrete the EGF bioactively to the media as demonstrated by radioreceptor binding assay. The EGF bioactivities secreted by human and monkey RPE cells were at peak of 48 hours (human RPE cells secreted 2.11 +/- 0.46 ng/ml vs monkey RPE was 1.56 +/- 0.12 ng/ml) in the serum-free media. The results indicate that the RPE is one of important sources for EGF in the eye. The RPE cells may play much important roles in the development of proliferative retinal diseases through the autocrine or paracrine mechanism. This new discovery will be helpful to elucidate the pathogenesis of proliferative retinal diseases and also provide an important basis for the treatment of such diseases.

Animals↗
PubMed1995

[A preliminary report of small incision cataract surgery by phacoemulsification].

The results of 34 cases with cataract extracted by phacoemulsification were preliminarily reported. Postoperatively, they achieved corrected visual acuities > 1.0 in 24 eyes (70.59%) in one week and in 25 eyes (73.53%) after 3 months. The post-operative astigmatism showed a tendency of change from with-the-rule shifting to against-the-rule. The rate of the corneal endothelial cell loss was 13.28%. No severe intra- and post-operative complications were found. It is concluded that the small incision, slight post-operative reaction and fast visual rehabilitation inherent in phacoemulsification procedures are more beneficial to patients than the conventional extracapsular cataract extraction.

Adult↗
PubMed1995

[Transjugular intrahepatic portosystemic shunt: indications, prevention and management of complications].

Transjugular intrahepatic portosystemic shunt (TIPS) was carried out in 140 cases of advanced cirrhosis with portal hypertension. The success rate of TIPS was 94.62%. The complication rate of TIPS was 16.15%, of which, 4.62% was TIPS procedure related including intraabdominal or intratheoracic bleeding and rebleeding of esophageal varices. The complication rate related to portosystemic shunt was 11.54% and the complications included encephalopathy and acute hepatic failure. The mortality of TIPS was 3.08% within one month following TIPS. 2.31% of patients died of hepatic failure and 0.77% died of rebleeding of varices.

Adult↗
PubMed1994

Mutational analysis of the translational signal in the human cytomegalovirus gpUL4 (gp48) transcript leader by retroviral infection.

A short upstream open reading frame (uORF2) in the human cytomegalovirus (CMV) gpUL4 (gp48) transcript leader is conserved among CMV strains and inhibits translation of a downstream cistron. Remarkably, this inhibitory effect depends on the amino acid coding information of uORF2, at least in transient transfection assays in diploid human fibroblasts. Using retroviral vectors, we now report that the gp48 leader inhibits downstream translation in multiple additional cell types, even when expressed from a stably integrated gene, and on a transcript containing an additional kilobase of complex leader sequences. The magnitude of inhibition can be augmented approximately 3- to 10-fold by replacing the context of nucleotides flanking the wild-type initiation codon of uORF2 with an optimal context, suggesting that leaky scanning past the wild-type AUG codon accounts for translation of the downstream cistron. Using an in vivo mutagenesis protocol that relies on reverse transcriptase infidelity, we isolated mutants in which the inhibitory effect of the gp48 leader was inactivated as a result of alterations in the coding information of uORF2. These studies demonstrate that, independent of the cell type or expression system used, CMV gp48 uORF2 is a potent translational inhibitory element.

3T3 Cells↗
PubMed1994

The hematopoietic stem cell antigen, CD34, is not expressed on the malignant cells in multiple myeloma.

Autologous stem cell transplantation has become an important therapy in multiple myeloma (MM). To develop adequate autograft purging methods, it is necessary to determine whether antigens expressed on early hematopoietic progenitors exist on malignant cells. The Ig heavy chain produced by the MM cells shows evidence of prior somatic mutation without intraclonal diversity. As a result, this sequence can be used as a specific marker to detect all members of the malignant clone. The Ig heavy chain sequence expressed by the MM cells was obtained in five patients with advanced disease. Patient specific oligonucleotide primers were designed based on the complementarity determining regions (CDR) of each MM Ig sequence and used to amplify DNA by polymerase chain reaction for the detection of malignant cells. A highly purified collection of CD34+ cells was obtained after passage of the initial bone marrow cells through an immunoadsorption column and fluorescence-activated cell sorting. Despite an assay sensitivity of 1 tumor cell in 2,500 to 44,000 normal cells, none of the CD34+ samples showed product with the myeloma-specific CDR primers. Therefore, positive selection for cells bearing this antigen should yield a tumor-free autograft capable of providing hematopoietic recovery after myeloablative chemotherapy.

Antigens, CD↗