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Biomedical subjects

L Chen

Publications and source records attributed to L Chen.

At least 1,531 records · Page 85Linked to original sources

Neurofibrillary change on Guam.

Distribution and occurrence of neurofibrillary change (NFC) in the brain were studied in 114 Guamanians who had neither amyotrophic lateral sclerosis (ALS) nor parkinsonism dementia (PD). Comparison was made with 28 Guamanians with ALS-PD and 53 non-Guamanians without ALS-PD. Search for NFC was made in 15 dogs and cats that lived on Guam. Most of the Guamanians without ALS-PD during and after middle age had NFC similar to that of Guamanians with ALS-PD but lesser in degree and extent of involvement. It is possible that the general population of Guam had been exposed to the unknown etiologic agent of ALS-PD during some previous period.

Adolescent↗

Synthesis of human interferon beta 1 in Escherichia coli infected by a lambda phage recombinant containing a human genomic fragment.

DNA from a human adult was fragmented by partial digestion with restriction endonuclease EcoRI and cloned in lambda Charon 4A. Clone C15, with a human DNA insert of 17 X 10(3) bases, was identified as containing a gene for the fibroblast interferon, interferon beta 1. Restriction mapping shows that this gene, located on a 1840-base EcoRI fragment, is not interrupted by introns. Moreover, we show that this human genomic DNA fragment is able to direct the synthesis of active human interferon beta 1 in Escherichia coli. Interferon activity of up to 7 X 10(6) U/l was recovered from phage lysates by chromatography on Cibacron blue--Sepharose, and had the same immunological properties and species specificity as interferon produced by human fibroblasts.

Adult↗

Adenosine 3',5'-monophosphate (cAMP)-binding proteins and cAMP-dependent protein kinases in bovine adrenal cortical cell plasma membrane.

A cAMP-binding protein and cAMP-dependent protein kinase have been identified and partially characterized in bovine adrenocortical plasma membranes. [3H]cAMP binding to the plasma membrane preparation demonstrates both high (Ka = 4.2 X 10(9) M-1) and low (Ka = 1.3 X 10(8) M-1) affinity binding sites. cAMP-dependent protein kinase was demonstrated using both bovine histone and endogenous substrates. The detergent-dependent solubilization characteristics of this cAMP-dependent protein kinase indicate that it is an integral membrane protein.

Adrenal Cortex↗

Preoperative and postoperative echocardiographic studies of pulmonic valvular endocarditis.

The echocardiographic manifestations of pulmonic valvular endocarditis in a patient with underlying heart disease consisting of a ventricular septal defect and infundibular stenosis are reported. The abnormal shaggy echoes observed on the pulmonic valve were confirmed to be vegetations based on surgical and pathologic findings. This was further proven by the disappearance of the shaggy echoes after surgical excision of the vegetations. We conclude that echocardiograms can detect the presence and disappearance of pulmonic valvular vegetations, which may be of aid in the diagnosis of pulmonic valvular endocarditis.

Adult↗

Steroid receptors in human renal carcinoma.

Glucocorticoid- and androgen-binding receptors were demonstrated in cytosol of human renal cell carcinomas by the dextran-coated charcoal technique. Sedimentation studies using preparative ultracentrifugation indicated a 7 to 8 S binding component. None of the renal carcinoma cells tested contained detectable estrogen receptors and a few samples had a very low but demonstrable progestin receptor level. In the normal kidneys tested, cytoplasmic components that bound only androgen could be detected. Competition studies showed that progestin competed for the glucocorticoid receptor sites in all the renal tumors tested, whereas diethylstilbestrol and testosterone were weak or not competitive. It is suggested that the response of some patients with renal carcinoma to high doses of progesterone or androgens could be explained by the ability of these hormones to block the activity of glucocorticoid receptors, which might be involved in tumor growth.

Adenocarcinoma↗

A testicular tumor with gingival metastasis.

Testicular tumors comprise approximately 1 percent of all malignant neoplasms in the male. However, they are one of the more common malignant diseases of adolescent and young adult males. An unusual case of a testicular neoplasm in a 23-year-old man exhibiting gingival metastasis is presented.

Adult↗