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Biomedical subjects

J Lu

Publications and source records attributed to J Lu.

At least 649 records · Page 36Linked to original sources
PubMed1991

Serum cholesterol concentration and coronary heart disease in population with low cholesterol concentrations.

OBJECTIVE: To examine the relation between serum cholesterol concentration and mortality (from coronary heart disease and from other causes) below the range of cholesterol values generally seen in Western populations. DESIGN: Prospective observational study based on 8-13 years of follow up of subjects in a population with low cholesterol concentrations. SETTING: Urban Shanghai, China. SUBJECTS: 9021 Chinese men and women aged 35-64 at baseline. MAIN OUTCOME MEASURE: Death from coronary heart disease and other causes. RESULTS: The average serum cholesterol concentration was 4.2 mmol/l at baseline examination, and only 43 (7%) of the deaths that occurred during 8-13 years of follow up were attributed to coronary heart disease. There was a strongly positive, and apparently independent, relation between serum cholesterol concentration and death from coronary heart disease (z = 3.47, p less than 0.001), and within the range of usual serum cholesterol concentration studied (3.8-4.7 mmol/l) there was no evidence of any threshold. After appropriate adjustment for the regression dilution bias, a 4 (SD 1)% difference in usual cholesterol concentration was associated with a 21 (SD 6)% (95% confidence interval 9% to 35%) difference in mortality from coronary heart disease. There was no significant relation between serum cholesterol concentration and death from stroke or all types of cancer. The 79 deaths due to liver cancer or other chronic liver disease were inversely related to cholesterol concentration at baseline. CONCLUSION: Blood cholesterol concentration was directly related to mortality from coronary heart disease even in those with what was, by Western standards, a "low" cholesterol concentration. There was no good evidence of an adverse effect of cholesterol on other causes of death.

Cerebrovascular Disorders↗
PubMed1991

Mannan-binding protein in human liver.

Mannan-binding protein (MBP) is a Ca(2+)-dependent lectin which was first described in 1978 in rabbit liver, and subsequently in serum and liver tissue from humans and a range of animal species. MBP structurally resembles C1q, and may act both as a focus for complement activation on the surface of microorganisms and as an opsonin in its own right. Low serum levels of serum MBP have been described in a group of children known to suffer from severe recurrent infections. MBP has also been reported to behave as an acute phase reactant. This preliminary study has investigated the localisation of MBP in human tissues using material obtained both at post mortem and from diagnostic liver biopsies. Using the IgG fraction of rabbit anti-human MBP, immunoperoxidase staining showed no evidence of significant MBP in a wide range of normal tissues, including liver taken both at post mortem and needle biopsy. However, there was a significant degree of staining for MBP in liver biopsies showing a variety of different pathologies, in particular severely damaged alcoholic livers, and those harbouring metastatic tumour. Moderate degrees of staining were also seen in liver biopsies from patients suffering from chronic biliary disease. It is uncertain whether this localisation of MBP in abnormal liver is an acute phase response, or represents a more fundamental link with liver disease. This question could be the focus for future studies.

Adolescent↗
PubMed1991

Capacity of making choices in the brain and its quantitative evaluation: an application to comprehension of incomplete sentences and semantic commitments.

The natural language processor in the brain generates information when it disambiguates words while reading a text in which information generation refers to making semantic commitments. Contextual facilitation of disambiguation of words appearing in the perturbed text that is derived from the unperturbed and natural one by deleting words randomly, lets the language processor revise the previous semantic commitments continuously. As the frequency of revising the previous semantic commitments increases, the amount of information generated by the language processor also increases. Revising previous semantic commitments in a continuous fashion is the functional property intrinsic to the language processor in the brain.

Brain↗
PubMed1991

Non-classical androgenic actions of RU38486 in androgen-responsive Shionogi carcinoma 115 cells in serum-free culture.

Antiglucocorticoid and antiprogestin RU38486 (RU486) stimulated the growth of highly androgen- and moderately glucocorticoid-sensitive SC-3 cells (a cloned cell line from Shionogi mouse mammary carcinoma 115) in a dose-dependent manner. A maximal 8-fold stimulation of growth by RU486 has been observed at 10(-7) M in a serum-free medium and its potency has been found to be almost the same as that of dexamethasone (Dex). The growth rate of SC-3 cells treated by triamcinolone acetonide (TA) or Dex combined with RU486 at 10(-9)-10(-7) M was enhanced compared to cells treated by TA or Dex alone, indicating that RU486 had additive rather than antagonistic effects. Our previous study revealed that RU486 could compete with the specific uptake of [3H]testosterone in intact SC-3 cells at relatively low affinity and the present study showed that the stimulatory effect of RU486 on the growth of SC-3 cells was significantly inhibited by pure antiandrogen flutamine and that half-maximal inhibition by flutamine was achieved at 10(-6) M. Moreover, we demonstrated that the conditioned medium from RU486-stimulated SC-3 cells contained growth-promoting activity which caused a 3.5-fold increase in DNA synthesis by SC-3 cells in the absence of RU486 and which was abolished by treatment with heparin-Sepharose. These results indicate that RU486-induced growth of SC-3 cells may be expressed as an androgenic activity through androgen receptor and mediated by a heparin-binding growth factor.

Animals↗
PubMed1991

Tissue distribution of mouse mammary tumor virus (MMTV) antigens and new endogenous MMTV loci in Japanese laboratory mouse strains.

The distribution of mouse mammary tumor virus (MMTV) antigens was studied by the immunoperoxidase method in the II-TES and I-TES mouse strains as well as their progenitors, CS and DBA/2 strains. In the II-TES, I-TES and CS strains, and BALB/c mice foster-nursed with these strains, MMTV antigens were found not only in epithelial cells of the mammary glands but also in those of other tissues including the seminal vesicle, vas deferens, epididymis, prostate, parotid, submandibular, lacrimal, sebaceous, and urethral glands. In DBA/2 and BALB/cfDBA/2 mice, however, the MMTV antigens were found only in the mammary glands. Electron microscopic examination showed MMTV particles in these organs. When we examined the presence of Mtv-1 and 2 proviruses, which are known to be responsible for MMTV expression, in the genomes of the II-TES, I-TES, CS and DBA/2 strains by Southern blotting, Mtv-2 was not found in any of the mice and Mtv-1 was found in the II-TES and DBA/2 mice but not in the I-TES and CS mice. Instead, four new endogenous MMTV loci, which have never previously been reported in laboratory mouse strains, were detected in the genomes of the II-TES, I-TES and CS strains. One (designated Mtv-42) was common in the three strains and the other three (designated Mtv-43, 44 and 45) were common in the II-TEX and I-TES strains or the II-TES and CS strains. These results thus suggest that new endogenous MMTV loci may be responsible for MMTV expression in a variety of tissues of these three strains.

Animals↗
PubMed1991

The human fibroblast growth factor receptor genes: a common structural arrangement underlies the mechanisms for generating receptor forms that differ in their third immunoglobulin domain.

To determine the mechanisms by which multiple forms of fibroblast growth factor (FGF) receptors are generated, we have mapped the arrangement of exons and introns in the human FGF receptor 1 (FGFR 1) gene (flg). We found three alternative exons encoding a portion of the third immunoglobulin (Ig)-like domain of the receptor. One of these alternatives encodes a sequence that is part of a secreted form of FGFR 1. The other two encode sequences that are likely part of transmembrane forms of FGFR 1. One of these forms has not been previously reported in published cDNAs. Also, we have determined the structural organization of a portion of the human FGFR 2 gene (bek) and found a similar arrangement of alternative exons for the third Ig-like domain. The arrangement of these genes suggests that there are conserved mechanisms governing the expression of secreted FGF receptors as well as the expression of at least two distinct membrane-spanning forms of the FGF receptors. The diverse forms appear to be generated by alternative splicing of mRNA and selective use of polyadenylation signals.

Amino Acid Sequence↗
PubMed1991

Design and compliance of HBV vaccination trial on newborns to prevent hepatocellular carcinoma and 5-year results of its pilot study.

A large-scale, controlled study of universal immunization of newborns against HBV infection has been conducted in the high incidence area of hepatocellular carcinoma, Qidong County of China. This area has a stable population, standardized cancer registration system, and an epidemiological base for measurements of liver cancer prevention by vaccine. Randomization was done on the community level. The vaccination and the control group each will consist of 38,000 children by the end of 1990. It is anticipated that the design will provide high statistical power to detect 50% reduction in the prevalence rate of chronic hepatitis among the vaccinees vs. the controls at 6 to 10 years of age, and 50% reduction in the incidence rate of hepatocellular carcinoma at 35 to 40 years of age. The vaccine used is Hep-B Vax, donated by Merck and Co. through WHO. The vaccine was administered at 0, 1, and 6 months after birth, the dosage of 5 or 2.5 micrograms in the pilot study as used before 1985 and of 5 micrograms dose level during the main study starting from January 1, 1985. About 85% of the cohorts have now entered the protocol. The vaccination coverage during 1984 to 1989 was 98.0% (35,064/35,789). Follow-up of the vaccinees and the age-matched controls at 5 years has exceeded 97%. The cumulative mortality in the vaccinated group up to 1988 was 1.29% (354/27,450). No single death nor serious adverse reaction was found that was associated with vaccination. The use of HBV vaccine at a reduced dose was especially important for the developing countries at the present time in order to achieve widespread immunization. Five-year results of the pilot study of this vaccination project showed that significant protection against HBV infection was achieved with the 5 or 2.5 micrograms per dose regimen plus a booster of 5 micrograms given at 3.5 to 4 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Hepatocellular↗
PubMed1991

Establishment and characterization of immortalized non-transplantable mouse mammary cell lines cloned from a MMTV-induced tumor cell line cultured for a long duration.

During the culturing of a mouse mammary tumor cell line, MuMT73, maintained in vitro for more than a decade, we found morphological heterogeneity in its cells; some showed contact inhibition in their growth, some formed domes and some grew criss cross and piled up. In trying to clone the cell line to isolate cells showing contact inhibition or dome formation, we were able to establish six clonal cell lines. These six cell lines were categorically divided into three groups according to their phenotypical behavior, Groups A, B and C. Group A (clones 1, 5 and 7) cells had a property of contact inhibition. They induced no tumor when injected into the subcutaneous tissue of the back, nor even when injected into the mammary fat pads or under the kidney capsule of syngenic or nude mice, and therefore were thought to be non-malignant in nature. They were positively stained by anti-keratin antiserum and had mouse mammary tumor viruses (MMTVs). Group B (clone 6) cells grew in a crisscross pattern and piled up, and they induced tumors when injected into the subcutaneous tissue of the back of mice. Group C (clones 3 and 4) cells formed domes in their growth and induced some tumors in the mammary fat pads and under the kidney capsule of KSN nude mice. In Southern blots with MMTV-env probe, numerous exogenous MMTV proviruses were detected in these cell lines. The insertion patterns of these proviruses in cells of non-malignant clonal lines (Group A) resembled those of malignant lines (Group B), except one band (about 26 Kb), but were considerably different from those of intermediate lines (Group C). On the other hand, no difference was detected in Southern blots with int-1 or int-2 probes among the non-malignant, intermediate and malignant clonal cell lines.

Animals↗
PubMed1991

[Phospholipid components of danggui].

This paper deals with the phospholipid components in Danggui (Angelica sinensis and Levisticum officinale) by using thin-layer chromatographic scanning and the corrective method of absorbance proportional coefficient. Seven known and two unknown phospholipid components were separated and determined. The authors have compared the composition of phospholipids for six Danggui samples.

Chromatography, Thin Layer↗
PubMed1991

[Impedance audiometry with 3-probe frequency].

The 3-probe frequency (226, 678, 1000Hz) admittance (Y), susceptance (B) and conductance (G) tympanograms were recorded from 28 normal-hearing adults with a GSI 33 Version 2 Middle-Ear analyzer, and the 3-frequency ipsilateral acoustic-reflex thresholds were measured too. In all subjects, there were normal values of tympanometric indices, such as peak compliances, peak pressures, gradients and ear canal volumes, and of ipsilateral acoustic-reflex thresholds at a 226-Hz probe tone. From 226 to 1000Hz, Y, B and G increased in magnitude while the corresponding admittance-,susceptance- and conductance-tympanogram peak pressures (PY, PB, PG) shifted towards positive evidently. In comparison with 226 Hz, the 678-Hz static admittance (Y') and static susceptance (B') values were large but had no significant differences as compared with those of 1000 Hz. The relation among Y, B and G, among PY, PB and PG, and between Y' and B' changed as a function of probe frequency from 226 to 1000 Hz. The average reflex thresholds of 25 adults (30 ears) were 83 dB HL at 226-Hz probe frequency, 91 dB at 678 Hz, and 88 dB at 1000 Hz, using a 1000-Hz tonal activator. There were significant differences among the 3 values (all P less than 0.01). The ipsilateral acoustic reflexes from 3 adults (4 ears) were present at 226-and 678-Hz probe tones, but not at 1000 Hz.

Acoustic Impedance Tests↗
PubMed1991

[Survey of fungi and bacterinum of the conjunctival sac in Guangzhou area].

This paper presents the results of fungal culture from healthy conjunctival sac in 178 eyes. The rate of positive culture of the fungi was 25% in farmers, 11.1% in cleaners, and 8.8% in city residents respectively. Culture for aerobic was carried out in the samples from conjunctival sacs of 137 eyes. The rate of positive culture was 71.9% in farmers, 80.6% in cleaners, and 23.2% in city residents respectively. On the other hand, the rate of fungal positive culture was 9.7% and that of aerobic was 30% in the patients managed with steroid eyedrops for more than one month. The aspergillus and penicillium were the most commonly seen species among the isolated fungal strain, whereas the staphylococci and streptococcus pneumonia were the most common among the isolated aerobic. The results run parallel to the fact that the main pathogens of ocular infection seen clinically are fungi and aerobics. The authors emphasize that the conjunctival sac should be disinfected to prevent infections caused by opportunistic pathogens.

Adolescent↗
PubMed1991

[The role of nucleus tractus solitarii (NTS) in acupuncture inhibition of visceral-somatic reflex (VSR)].

Experiments were carried out on 164 rabbits. The transmission of abdominal vagal impulses and the mechanism of inhibitory effect by acupuncture systematically were investigated. 1) Electrical stimulation (single pulse of 20 V, 0.5 ms) of abdominal vagus nerve (AVN) produced two kinds of potential on cervical vagus nerve: the fast wave (10.4-24.4 M/sec) and the slow wave (0.9-1.7 M/sec), the later was more stable. 2) In dorsal medulla oblongata the 'M' shaped evoked potentials with long duration (100 ms or so) were recorded. The results suggest that afferents from AVN are mainly transmitted through the small fibres and multi-synaptic connections in Medulla. 3) Out of 301 response units, 281 units (93.6%) concentrated in NTS and adjacent regions. This result was also confirmed by injection of Horseradish Peroxidase (HRP) in the trunk of AVN. 4) On 24 awake rabbits the VSR were elicited by strong stimulation of AVN. Electroacupuncture (EA) on "Zusanli" points inhibited VSR, an effect lasted over 20 min. This inhibitory effect of EA was reversed partly by Naloxone (0.5 mg/kg iv) and was attenuated after lesion (DC 0.5 mA, 1 min.) of NTS. In conclusion, NTS plays an important role in suppression of VSR by EA (P less than 0.01).

Abdominal Pain↗
PubMed1990

Interaction of androgen-induced autocrine heparin-binding growth factor with fibroblast growth factor receptor on androgen-dependent Shionogi carcinoma 115 cells.

Stimulation of a Shionogi carcinoma 115-derived cultured cell line (SC-3) with androgen resulted in secretion of heparin-binding growth factor. In this study, we analyzed cell-surfaced receptors for growth factors. Binding data of growth factors on intact SC-3 cells revealed the presence of low and high affinity receptors for epidermal growth factor (EGF), insulin, and fibroblast growth factor (FGF). The dissociation constant values were 50 pM and 1.0 nM for EGF, 1.2 nM and 30 nM for insulin, and 34 pM and 7.5 nM for FGF. The numbers of maximal binding sites were 300 and 900/cell for EGF, 2,000 and 14,000/cell for insulin, and 13,000 and 810,000/cell for FGF. To examine the association of androgen-induced growth factor with one of these receptors, the conditioned medium prepared from androgen-stimulated SC-3 cells was fractionated through a heparin-Sepharose column. Growth factor activity adsorbed and eluted by 1 M NaCl from the column was comigrated with the activity inhibiting FGF-receptor association. In addition, basic 125I-FGF was cross-linked, using disuccinimidyl suberate, to the receptor with an apparent molecular weight of 130,000, whose labeling was inhibited when basic FGF, acidic FGF, or highly purified androgen-induced growth factor was present in excess. Furthermore, the highly purified growth factor-, basic FGF- or androgen-induced growth of SC-3 cells was significantly and similarly inhibited by anti-basic FGF antibody IgG. These results indicate that androgen-induced FGF-like factor acts as an autocrine growth factor via the FGF receptor in a process of SC-3 cell proliferation.

Animals↗
PubMed1990

Low levels of chromosomal mutations in germ cells derived from doxorubicin-treated stem spermatogonia in the mouse.

The mutagenic effects of doxorubicin (Adriamycin, ADR) on mouse spermatogonial stem cells were examined by analysis of spermatocyte chromosomes and of dominant lethality transmitted through the spermatozoa. The effects of ADR on mutations, cytotoxicity, and sperm head abnormalities were compared with those of radiation. The cytotoxic effect of 6 Gy of gamma-radiation on stem spermatogonia was equivalent to about 4-5 mg ADR/kg. Chromosomal translocations were observed in 0.6% of the spermatocytes of mice treated with ADR (2-6 mg/kg). In contrast, 6 Gy of radiation induced translocations in 11.1% of spermatocytes. No increase in dominant lethality was observed after treatment with ADR at doses up to 6 mg/kg, while the frequency after 6 Gy of radiation was 3.6%. Based on these results, ADR would be expected to be only a weak inducer of balanced chromosomal rearrangements. Because ADR at 4.5 mg/kg was much weaker than 6 Gy of gamma-radiation at inducing chromosomal translocations, but just as effective at inducing sperm head abnormalities, the level of sperm head abnormalities is not indicative of balanced chromosomal rearrangements induced in stem spermatogonia by cytotoxic agents.

Animals↗
PubMed1990

Topographic variations in W-cell input to cat superior colliculus.

Most of the retinal input to the cat's superior colliculus (SC) arises from W-cells of the contralateral eye and terminates just below the tectal surface. The goal of this study was to determine whether the strength of this input is uniform over the collicular map or, instead, exhibits topographic variations as has been reported for the retinotectal Y-cell projection (McIlwain and Lufkin 1976). Monosynaptic inputs from the principal W-cell projection mediate the late negative potential (LNP), a collicular field potential that can be evoked by shocks to the optic pathway. We assumed that the amplitude of the potential provided a measure of the strength of the W-cell input to the upper superficial gray layer. Using a fixed stimulus, we measured the maximal amplitude of the LNP at 90 topographically identified tectal sites in 5 cats. The amplitude of the LNP varied as much as 5-fold over the SC and was systematically related to the azimuthal position of the recording site. LNP amplitudes were consistently smallest in the representation of the area centralis and vertical meridian and largest in the representations of the contralateral hemifield periphery and the ipsilateral hemifield. There was little systematic variation in LNP amplitude as a function of elevation in the map. The observed variations did not result from non-uniform activation of retinal afferents or drift in properties of the recording electrodes, stimuli, or preparation. The results suggest that the principal W-cell input to the SC is weaker in the representation of the area centralis than elsewhere in the map.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1990

Growth stimulation by androgens, glucocorticoids or fibroblast growth factors and the blocking of the stimulated growth by antibody against basic fibroblast growth factor in protein-free culture of Shionogi carcinoma 115 cells.

Shionogi carcinoma 115 (SC115) has been accepted for 20 years as an androgen-responsive mouse mammary tumor. We have established an androgen-dependent cloned cell line (SC-3) from a SC115 tumor. In a serum-free medium, testosterone (T) or fibroblast growth factors (FGFs) markedly stimulate the growth of SC-3 cells, and the T-induced growth was shown to be mediated through FGF-like peptide(s) in an autocrine mechanism. Since we used the serum-free culture including 0.1% bovine serum albumin (BSA), a partially serum-containing condition, putative roles of BSA- or serum-borne growth factors in growth stimulation of autocrine production of FGF-like peptide(s) could not be excluded. This paper reports findings performed in a protein-free medium including plating [Ham's F-12:MEM (1:1; v/v)]. In the protein-free culture, the growth of SC-3 cells was significantly stimulated by the addition of greater than or equal to 10(-10) M T (up to 20-fold), greater than or equal to 10(-7) M dexamethasone (Dex; up to 7-fold) or greater than or equal to 1 ng/ml basic (b) or acidic FGF (up to 10-fold); other various growth factors had no such effects. Furthermore, DNA synthesis of SC-3 cells induced by T, Dex or bFGF was similarly and markedly inhibited by bFGF neutralizing antibody IgG. Therefore, the present findings seem to demonstrate that androgens or high levels of glucocorticoids induce the production and secretion of FGF-like peptide(s) from SC-3 cells for their growth even in the absence of additional support by other factors.

Androgens↗