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Biomedical subjects

L Cai

Publications and source records attributed to L Cai.

At least 145 records · Page 8Linked to original sources
PubMed1995

[Report of a case of glucagonoma misdiagnosed as "eczema" and "hepatic angioma" for three years and review of literature].

Glucagonoma is a rare pancreatic tumor, necrolytic migratory erythema is its distinctive feature and it is often associated with diabetes mellitus, weight loss, anemia, hypoaminoacidemia, glossitis and stomatitis. We reported a case of glucagonoma misdiagnosed as "eczema" and "benign hepatic anginoma" for 3 years. His blood glucagon level was 1,758 ng/L. The results of abdominal B-mode ultrasonography and CT scan were negative, but selected arteriogram showed a tumor mass between the pancreatic body and tail. Before operation, treatment with octreotide and supply of amino acids were given with improvement of the skin lesion. After resection of the tumor from pancreas, necrolytic migratory erythema disapeared, but his blood level of glucagon and amino acids did not improve. It is suggested that any diabetic patient with chronic skin damage should be checked for blood glucagon level. In suspected cases, selected arteriogram will be helpful for location of the tumor. Vigorous resection of the pancreatic tumor should be done as soon as possible, even though there is already metastases.

Diagnostic Errors↗
PubMed1995

[Expression of desmoplakin II in tumors].

Desmoplakin II (DPII) is a new marker for identification of epithelium and epithelial tumors. Expression of DPII in 217 tumors cases was studied immunohistochemically by ABC method using an anti-DPII monoclonal antibody which reacts with tissue on formalin-fixed, paraffin-embedded sections. A monoclonal antibody against cytokeratin (CK) was employed to compare with the antibody. Immunohistochemical staining showed that 147 of the 163 epithelial tumors and bi-directional differentiation tumors expressed DPII (90.7%); 92 of the 163 tumors expressed CK (56.4%); 54 tumors lacking desmosome expressed neither DPII nor CK. All CK positive staining was located in cytoplasm while most DPII positive dotty staining was located at the cell-cell borders, some DPII staining was present in cytoplasm. These results demonstrate that the anti-DPII monoclonal antibody is a useful immunohistochemical probe for identification of desmosome-containing tumors. Antibodies against other epithelial markers such as keratin should be employed together with anti-DPII monoclonal antibody when differentiation is made between epithelial and non-epithelial tumors.

Adenocarcinoma↗
PubMed1995

Pre-exposure of mice to low dose or low dose rate ionizing radiation reduces chromosome aberrations induced by subsequent exposure to high dose of radiation or mitomycin C.

The phenomenon of cytogenetic adaptive and cross-adaptive response induced by low dose irradiation and chemical mutagen in mice is described. We found, firstly, that adaptation can be induced by acute low dose X-irradiation (0-100 mGy). Secondly, a cross-adaptation can occur between X-irradiation and mitomycin C (MMC). And finally, mice pre-exposed to chronic low dose rate 60Co-Gamma irradiation (0-226.0 mGy/day) are less susceptible to chromosome aberration induced by subsequent acute higher X-irradiation. Therefore, our data suggest that radioadaptive response depends on dose, dose rate and time interval. Possible mechanisms are also discussed.

Adaptation, Physiological↗
PubMed1995

[Interleukin-2 gene cloning and expression in S. cerevisiae].

Mature human Interleukin-2 gene was amplified from IL-2 cDNA by PCR methods. The PCR product was cloned into pUC12 plasmid at Sma I site, then precisely engineered into an intermidiate vector pSK43SB which were digested with Hind III, mung bean nuclease, and Sal I. Added BamH I linker to Cla I site of pSK43SB-IL2 to produce one more BamH I site, then digested pSK43DB-IL2 with restriction enzyme BamH I, the BamH I fragment with an alpha-factor leading sequence, IL2 gene and cycl terminater were produced. It was then cloned into a typical high efficiency episomal expression vector YEpHc8. Human IL-2 protein was purified from supernatant secreted by yeast transformants of YEpHc8-IL2 leading by alpha-factor promoter with IL-2 right translational reading frame and accurate cleavage site. High level expression of IL-2 with highly activity has been purified. A sugar specific silver staining method and 3H sugar labelling experiment has shown the detection of carbohydrate component.

Cloning, Molecular↗
PubMed1994

Crystal structure of a four-stranded intercalated DNA: d(C4).

The crystal structure of d(C4) solved at 2.3-A resolution reveals a four-stranded molecule composed of two interdigitated or intercalated duplexes. The duplexes are held together by hemiprotonated cytosine-cytosine base pairs and are parallel stranded, but the two duplexes point in opposite directions. The molecule has a slow right-handed twist of 12.4 degrees between covalently linked cytosine base pairs, and the base stacking distance is 3.1 A. This is in general agreement with the NMR studies. A biological role for DNA in this conformation is suggested.

Computer Graphics↗
PubMed1994

Cytogenetic adaptive response with multiple small X-ray doses in mouse germ cells and its biological influence on the offspring of adapted males.

Cytogenetic adaptive response of mouse germ cells was studied by exposing male mice to a sequence of 4 conditioning doses of 0.05 Gy each (D1) administered at 10-day intervals and subsequently to a single challenging dose of 1.5 Gy (D2). In concurrent experiments, male mice after treatment with D1 doses alone were mated to unirradiated females and the F1 males were given the D2 dose. Chromosomal aberrations in both spermatocytes and bone-marrow cells and UV-induced UDS in splenocytes of these mice were studied. Adapted mice (i.e., D1 + D2 exposures) responded with a significantly lower frequency of chromosomal aberrations than the non-adapted (D2 exposure only) controls. The relative reduction in frequencies was, however, similar to that observed in earlier work with a single conditioning dose of 0.05 Gy. The frequencies of chromosomal aberrations in spermatocytes and bone-marrow cells as well as the levels of UV-induced UDS in splenocytes of the F1 males in the group D1 to fathers + D2 to F1 males were the same as those in F1 males which received only the D2 exposure.

Adaptation, Physiological↗
PubMed1994

Myometrial expression of mRNA encoding epidermal growth factor receptor (EGFR) throughout the menstrual cycle.

PROBLEM: To investigate the quantitative changes in expression of EGFR mRNA in the myometrium throughout the menstrual cycle. METHOD: Myometrium was collected at hysterectomy from 27 women with a history of regular cycles. Total RNA (20 micrograms) was isolated and analyzed by Northern blot using a human EGF-R specific 32P-labeled cDNA probe. The hybridization signals were quantified by densitometry, standardized, and reported in densitometry signal units (DSU). Endometrial specimens from the same uteri were simultaneously evaluated for histologic dating of menstrual cycle day. EGFR gene expression in endometrium was previously reported. Statistical significance of the differences in myometrial gene expression between menstrual phases was evaluated by student's t test. RESULTS: EGFR mRNA was expressed in all myometrial tissues tested. Levels were higher in the late proliferative phase than in all other phases (P < .05). Women over 40 years old had lower proliferative phase expression than younger women. CONCLUSION: This data suggests that myometrial EGFR mRNA expression varies in association with the histologic phases of the normal menstrual cycle, and may be affected by aging, even when cycles occur at regular intervals.

Adult↗
PubMed1994

[Amplification, cloning and sequencing of beta nerve growth factor gene in the Chinese population].

Genomic DNA was extracted from white blood cells. Using the genomic DNA as template, the gene encoding nerve growth factor (beta-NGF) in the Chinese population was amplified using polymerase chain reaction (PCR). The beta-NGF gene obtained by PCR was then cloned into plasmid pUC 12 which was digested with SmaI. After transformation, screening and identification, 8 clones containing the beta-NGF gene were analyzed. Nucleotide sequence of the NGF was determined by dideoxy-nucleotide chain-termination method. The sequencing result showed that there are 6 differences between the beta-NGF sequence of the Chinese population and previous reported beta-NGF sequence.

Amino Acid Sequence↗
PubMed1994

65 cases of preserving pylorus pancreatoduodenectomy: experience and problems.

Sixty-five patients with neoplasm (62 cases) or pancreatitis (3 cases) were treated with preserving pylorus pancreatoduodenectomy (PPPD) from 1984 to 1991. One postoperative death occurred. Follow-up studies were performed in 35 patients who had been treated by PPPD or the standard Whipple's procedure; they were questioned carefully concerning clinical symptoms. Further studies were performed in 20 patients with or without pylorus preservation (10 patients, respectively). Nutritional status and gastrointestinal digestive and absorptive functions were evaluated by determination of serum components, gastric analysis, barium emptying time, D-xylose absorption test, 14CO2 breath test, PABA, and other methods. The results demonstrated malnutrition and postgastrectomy syndromes in some patients after the standard Whipple's procedure, but not in those with PPPD. The quality of life was better in the latter. Pylorus preservation may be the main reason for this above difference. Delayed gastric emptying in the early postoperative period was a complication in some patients (21%) treated by PPPD. We recommend PPPD for pancreatoduodenectomy.

Adenocarcinoma↗
PubMed1994

[Detection of specific DNA fragment of Plasmodium falciparum by solid phase PCR].

Solid phase PCR for detecting Plasmodium falciparum was established and used to detect cultured FCCl/HN isolate and malaria patients in Yunnan Province. The results revealed that the sensitivity of the method for detecting FCCl/HN isolate DNA was as minimal as 0.2 pg, or about 10 parasites. The specificity of the method was confirmed by discriminating malaria patients infected with different species of Plasmodium. The results suggest that solid phase PCR is a specific and sensitive method for early detection of P. falciparum.

Animals↗
PubMed1993

A physiological role of peptide YY on exocrine pancreatic secretion in rats.

BACKGROUND: Peptide YY (PYY) given intravenously was shown to inhibit pancreatic exocrine secretion both in the dog and the rat. However, a possible physiological role of PYY on the pancreatic secretion has not been clarified. The present study was undertaken to investigate its physiological role on the exocrine pancreas. METHODS: In conscious rats, plasma PYY was determined in response to oral ingestion of a 6-mL meal and intravenous infusion of PYY; small intestinal transit time was measured by phenol red as a nonabsorbable marker, and pancreatic secretory studies were performed in rats with pancreatic fistulas and jugular vein catheters. RESULTS: Oral ingestion of the meal (containing phenol red, 1.6 mg/100 mL) significantly increased plasma PYY within 30 minutes. During this period, most (97%) of the phenol red was detected in the proximal two-thirds of the small intestine. Intravenous infusion of PYY in 25, 50, and 100 pmol.kg-1 x h-1 produced a dose-dependent increase in plasma PYY. The dose of PYY that simulated the peak postprandial level was 50 pmol.kg-1 x h-1, and this dose of PYY significantly inhibited the pancreatic secretion stimulated by physiological doses of secretin and cholecystokinin-8 (CCK-8). After the meal, pancreatic secretion of bicarbonate and protein significantly increased in rats pretreated with normal rabbit serum, whereas this increase was significantly augmented in rats pretreated with an anti-PYY serum because the postprandial increase in plasma PYY was abolished. CONCLUSIONS: PYY plays a regulatory role in the postprandial pancreatic exocrine secretion in rats.

Animals↗
PubMed1993

Induction of an adaptive response to dominant lethality and to chromosome damage of mouse germ cells by low dose radiation.

In the present paper, dominant lethal mutations, chromosome aberrations in spermatocytes and reciprocal translocations in stem spermatogonia were analyzed after whole body exposure of mice to X-radiation. Results both from chromosome aberrations in spermatocytes and for reciprocal translocations in spermatogonia showed that pre-exposure to low doses up to 200 mGy could induce a significant dose-dependent reduction in adapted mice compared to the non-adapted mice; the lower the adaptive dose, the greater the reduction. For dominant lethal mutations, it was found that spermatogonia (both stem cells and differentiated cells) and spermatocytes adapted to 50 mGy X-rays could show an adaptive response, but spermatids and spermatozoa could not.

Adaptation, Physiological↗
PubMed1993

Serological evidence of Coxiella burnetii infection in wild animals in Japan.

One hundred and thirty-four (26%) of 511 sera from 11 wild animal species in eight prefectures in Japan had antibody titers to Coxiella burnetii by the enzyme-linked immunosorbent assay. High prevalences were observed in Japanese black bears (Ursus thibetanus) (78%), Hokkaido deer (Cervus nippon yesoensis) (69%), Japanese hares (Lepus brachyurus) (63%), Japanese deer (Cervus nippon centralis) (56%), and to some extent in Japanese monkeys (Macaca fuscata) (28%). A low prevalence (13%) was observed in nutrias (Myocastor coypus). Japanese serows (Capricornis crispus), wild rats (Muroides sp.), raccoon dogs (Nyctereutes procyonoides viverrinus), wild pigs (Sus scrofa leucomystax), and masked palm civets (Paguma larvata) had no detectable antibodies to C. burnetii. Thus, six of 11 wild animal species in Japan were exposed to C. burnetii. Based on the high prevalences in some species, they may be a potential source of infection to both domestic animal and human populations.

Animals↗
PubMed1992

Prevention of thrombus growth by antithrombin III-dependent and two direct thrombin inhibitors in rabbits: implications for antithrombotic therapy.

We compared the abilities of heparin and two direct thrombin inhibitors to prevent fibrin accretion onto pre-existing thrombi in rabbits. Inhibition of thrombus growth was measured as the ability of each test compound to inhibit the accretion of 125I-fibrin onto thrombi pre-formed in jugular veins of rabbits. When administered as a continuous infusion, the two direct (i.e. antithrombin III-independent) thrombin inhibitors, r-hirudin and a tripeptide, Ac(D)-Phe-Pro-bor-Arg (P-8714) inhibited fibrin accretion as effectively as heparin, but did so in doses which generated little systemic anticoagulation, as compared to the marked anticoagulation associated with the heparin effect. However, both r-hirudin and P-8714 were more effective when they were administered as a single bolus injection than as a continuous infusion. Under the former conditions, there was only a transient systemic anticoagulant effect. We conclude that direct or antithrombin III-independent thrombin inhibitors are more effective than heparin in preventing thrombus growth. The limited effect of heparin is likely due to fibrin impairing the ability of heparin/antithrombin III to inactivate thrombin.

Amino Acid Sequence↗