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Biomedical subjects

C Li

Publications and source records attributed to C Li.

At least 1,207 records · Page 67Linked to original sources
PubMed1985

Evidence for proctolin-like substances in the central nervous system of the leech Hirudo medicinalis.

The distribution of proctolin-like immunoreactive (PLI) cells was mapped in the central nervous system of the leech Hirudo medicinalis. In segmental ganglia, PLI cells can be divided into two groups: cells that stain repeatedly in every successive ganglion, and cells that stain only in specific segmental ganglia. The number of PLI cells, therefore, ranged from eight to 20 cells per ganglion. One bilateral pair of PLI cells (cells PLI-1) was further characterized morphologically by Lucifer yellow and horseradish peroxidase cell injections. Cell PLI-1 conforms in soma position, morphology, and physiological properties with cell 101, which has been previously classified as an inhibitory motoneuron to the flattener muscles. A locust bioassay (O'Shea and Adams, Science 213:567-569, 1981) was used to detect the presence of proctolin-like bioactivity. Extracts of leech ganglia when applied to the extensor tibialis muscle of the locust leg induced a proctolin-like response similar to the responses induced by proctolin standards. This work extends the finding of proctolin-like substances to the annelid phylum.

Animals↗
PubMed1985

Keshan disease: an endemic cardiomyopathy in China.

Keshan disease is an endemic cardiomyopathy in China. Morphologically, the condition is characterized by multifocal necrosis and replacement fibrosis of the myocardium, resulting in acute or chronic heart failure. Some patients with Keshan disease show the clinical features of congestive (dilated) cardiomyopathy, but the pathologic features of the two conditions are different. The etiology of Keshan disease remains unknown. It is likely that numerous agents work synergistically to cause the disease.

Adolescent↗
PubMed1985

China's experiences in the quality control of its 1982 population census.

The author reports on experiences with China's 1982 census, which covered approximately one billion people and 19 census items. It is noted that "the postenumeration sample survey indicates that the quality of the census enumeration is: 0.071% of overcounts and 0.056% of undercounts. The paper presents principles governing quality control in the population census and explains a series of quality control procedures adopted to reduce possible errors originating in census planning, enumeration and data processing."

Asia↗
PubMed1985

FMRF-amide-like substances in the leech. I. Immunocytochemical localization.

FMRF-amide-like immunoreactivity (FLI) was localized to approximately 50 neurons in each segmental ganglion of the medicinal leech using immunocytochemical techniques. Although most of these neurons were iterated in each segmental ganglion, some were more restricted in their segmental distribution. The head and tail ganglia likewise contained numerous FMRF-amide-like immunoreactive cells. In addition to cell bodies, many nerve processes and varicosities were also immunoreactive throughout the ganglion. All labeling of FLI was blocked by preabsorption of the anti-FMRF-amide antiserum with synthetic FMRF-amide. Using a combination of Lucifer Yellow cellular injection and indirect immunofluorescence techniques, we identified several of the neurons possessing FLI. Identified neurons included excitatory motor neurons (HE, RPE, LPE, AE, and L), the HA modulatory neuron, interneuron cell 204, and cells of unknown function (AP). The processes of HE motor neurons and HA modulatory neurons which innervate the heart tubes were also immunoreactive. These results indicate a role for FMRF-amide-like substances as neurochemical signals in the leech.

Animals↗
PubMed1985

FMRF-amide-like substances in the leech. II. Bioactivity on the heartbeat system.

In the preceding paper (Kuhlman, J. R., C. Li, and R. L. Calabrese (1985) J. Neurosci. 5: 2301-2309) FMRF-amide-like immunoreactivity was localized to a specific set of neurons in the leech. Three types of these neurons are involved in controlling the animal's heartbeat: HE motor neurons and HA modulatory neurons which directly innervate the hearts, and the swim-initiating interneurons (cells 204) which can accelerate the heartbeat central pattern generator. Application of synthetic FMRF-amide had effects on the hearts and the heartbeat central pattern generator that mimicked the actions of the HA and cell 204 neurons. Bath application of FMRF-amide (10(-7) to 10(-6) M) to the hearts activated their myogenic rhythm and increased their beat tension, thus mimicking the effects of activity in HA cells. Bath application of lower concentrations of FMRF-amide (10(-9) to 10(-8) M) to the isolated central nervous system dramatically accelerated the central motor program for heartbeat, thus mimicking the effects of activity in cell 204. These observations suggest that an FMRF-amide-like substance may be used as a chemical signal by HA and cell 204 neurons. The role of the FMRF-amide-like substance contained in HE motor neurons remains unclear, but it may be released along with the HE cell's neuromuscular transmitter, acetylcholine.

Animals↗
PubMed1984

Absence of antibodies to ethinyl estradiol in users of oral contraceptive steroids.

Sera from current and past oral contraceptive users, never-users, and never-users with venous thrombosis were examined for immunoglobulin G (IgG) which was precipitable at 25% or 33% saturation with ammonium sulfate or which showed specific binding of ethinyl estradiol. No increase in "specific" IgG and no evidence of ethinyl estradiol binding was observed in oral contraceptive users. This provides no support for the claim that a significant percentage of oral contraceptive users develop a special IgG, precipitable at 25% ammonium sulfate saturation and showing high binding affinity to ethinyl estradiol, which may be causally linked to the development of thrombotic phenomena in oral contraceptive users.

Antibodies↗
PubMed1982

Infective endocarditis caused by Paecilomyces varioti.

The first reported case of Paecilomyces varioti endocarditis occurring on a porcine heterograft prosthesis is presented and the clinical and pathological features described in the four previously reported cases of prosthetic valvular endocarditis caused by this organism are reviewed. In each case, infection became apparent more than two months after cardiac surgery. Three of the four patients with infected aortic prosthesis developed outflow obstruction secondary to valvular vegetations. All patients died regardless of medical or surgical intervention. Appropriate therapy remains unknown.

Adult↗
PubMed1982

Kinetic studies of haemopoietic progenitor cells (CFU-C) and T-lymphocytes in the liver of human foetus.

In the development of human foetus, liver is an important haemopoietic organ. We have determined the liver weight and total hepatic nucleated cells from 24 foetuses on the one hand, and CFU-C yield, total number of CFU-C and T-lymphocytes in liver from 22 foetuses of different ages on the other. From the kinetic observations through the early developmental period of the foetuses, the maximum yield of CFU-C or the total number of CFU-C in the liver occurs at 4-5 months of gestation; during the first 5 months of gestation the percentage of T-lymphocytes in the liver is about 1-2%.

Cells, Cultured↗
PubMed1981

Cyclic urea and thiourea derivatives as inducers of murine erythroleukemia differentiation.

A series of derivatives of tetramethylurea, a known inducer of the differentiation of Friend erythroleukemia cells, has been synthesized and tested for its capacity to induce erythroid maturation, as measured by the synthesis of hemoglobin. Cyclic urea and thiourea derivatives consisting of five-, six-, and seven-membered ring systems containing N-alkyl substituents were prepared. Most of these agents were relatively effective inducers od differentiation, with N-alkyl substitution appearing to be essential for maximum response. The most potent agents developed were N,N'-dimethyl cyclic ureas. Exposure to concentrations of 2 to 4 mM of these derivatives resulted in more than 90% of the cell population achieving a differentiated state. Under these conditions, the parent compound, tetramethylurea, was slightly less efficacious, causing differentiation of only 68% of the population at its maximum effective level of 4 mM.

Animals↗
PubMed1981

Induction of differentiation of leukemia cells in vitro by N-substituted amides, lactams, and 2-pyridones.

N-Substituted amides, lactams, and 2-pyridones were examined for their ability to induce leukemic cell differentiation in vitro. These substituted amides were effective inducers of the differentiation of murine erythroleukemia (Friend) cells, as judged by the cellular accumulation of hemoglobin. N-Substitution increases the effectiveness of all classes of agents as inducers of maturation as judged by an increase in potency. N-Cyclohexylacetamide appeared to be a particularly effective compound, causing 92% of the population to synthesize hemoglobin at a concentration which was not inhibitory to cell replication. In the lactam series, an increase in ring size was paralleled by an increase in the potency of unsubstituted compounds, but ring size had less effect on N-substituted lactams. Increasing the chain length of the N-alkyl substituent had little additional effect on a series of lactam and 2-pyridone derivatives; however, some decrease in maximal induction occurred with butyl- and hexyl-substituted 2-pyridones. N-Isopropyl-2-pyridone, selected for further study, was as good an inducer of the HL60 human promyelocytic leukemia as it was of the Friend murine erythroleukemia.

Amides↗