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Biomedical subjects

J Y Lin

Publications and source records attributed to J Y Lin.

At least 109 records · Page 6Linked to original sources
PubMed1993

Glucose effects in an ovarian cancer protocol of exceptional activity.

A French multidrug protocol for stage III ovarian cancer has achieved 77% pathologic complete response, 100% total response, and 81% actuarial 4-year survival. Our analysis indicates that these rates exceed typical with very high statistical significance. Yet neither the drugs, the combined intravenous and intraperitoneal mode of delivery, nor potential bias in the predominantly suboptimal patient population appear to explain the protocol's exceptional results. Here we propose that the atypical administration of intraperitoneal glucose prior to drugs underlies the unusual activity of this protocol. We review studies demonstrating that high-dose glucose has pronounced effects on cancer cells, most notably, substantial potentiation of certain antineoplastic agents. We consider possible mechanisms of such glucose potentiation, including hypothesized osmotic effects that would be especially strong under intraperitoneal administration. We conclude that the French ovarian cancer protocol may represent a significant advance and that glucose potentiation may be more widely applicable as an adjunct to cancer chemotherapy.

Actuarial Analysis↗
PubMed1993

Bombesin and neurotensin excite neurons in hypothalamic arcuate nucleus in brain slices: an extracellular single-unit study.

Using extracellular single-unit recording in brain tissue slices, the effects of bombesin (Bomb), neurotensin (NT), and their analogs on hypothalamic arcuate (ARC) neurons were tested in this study. Adult ovariectomized Sprague-Dawley rats were used for obtaining the brain slices. Both Bomb and NT in pmol ranges stimulated nearly 70% of ARC neurons tested and the effects were all very significant. [D-Trp11]-NT, a NT analog, behaved more like an analog of NT instead of an antagonist, although [Leu13-psi(CH2NH)-Leu14]-Bomb, a Bomb receptor antagonist, could not block most of Bomb's effects on ARC neurons. The significant effects of Bomb and NT shown in this report indicate that both peptides may play significant roles in the neuroendocrine control system.

Animals↗
PubMed1993

Effects of various neuroactive substances on single-unit activities of hypothalamic arcuate neurons in brain slices.

Extracellular single-unit activities of 288 dorsomedial/ventrolateral hypothalamic arcuate (ARC) neurons were studied electrophysiologically in brain slices in vitro. We tested the effects of several neuroactive substances plus some of their analogs in this study. Among them, baclofen, a GABAb-receptor agonist, inhibited 95.6% of ARC neurons tested, although GABA itself was much less effective (23.8%). About half of baclofen's effect was blocked by phaclofen, a GABAB antagonist. Serotonin and dopamine also exhibited mostly inhibitory effects on responsive ARC neurons (80 and 78.4%, respectively), although more than half ARC neurons tested (53.3% of 169) were not responsive to dopamine. Neither ketanserin, a 5-HT2, nor domperidone, a D2 receptor antagonist, had much effect on blocking the actions of 5-HT or DA. Histamine and carbachol excited 67.4% and 52.2% of ARC neurons tested, respectively. Moreover, their effects were completely blocked by pyrilamine, a H1, and atropine, a muscarinic receptor antagonist, respectively. Ranitidine, a H2 receptor antagonist, however, was less effective. Norepinephrine had about equal number of excitation (33.3%) and inhibition (38.5%) on ARC neurons. Cholecystokinin-octapeptide sulphate (CCK-8S), a neuropeptide tested exerted potent excitatory effects on ARC neurons (62.8% of 137). In summary, ARC neurons in a more localized region aiming at the tuberoinfundibular dopaminergic neurons were selected in this study. Their responses to many agents and the implications on the regulation of prolactin secretion were discussed.

Animals↗
PubMed1993

The complete amino acid sequence of a Kunitz family trypsin inhibitor from seeds of Acacia confusa.

The complete amino acid sequence of a Kunitz-type two-chain trypsin inhibitor was determined for the first time. The sequence of the inhibitor from Acacia confusa (ACTI) was determined by analysis of peptides obtained from the reduced and S-carboxymethylated protein by digestion with endopeptidase Lys-C, endopeptidase Arg-C, and V8 endopeptidase. ACTI is comprised of two chains, namely A and B chains linked by the disulfide bridge between Cys(133) and Cys(141), and the inhibitor consists of 175 amino acid residues, 136 residues in the A-chain and 39 residues in the B-chain. The N-terminal amino acid sequence of ACTI shows extensive homology to the trypsin inhibitors from Acacia elata and Albizzia julibrissin, while the whole amino acid sequence of ACTI has a high degree of homology to the other Kunitz-type trypsin inhibitors from soybeans, winged bean seeds [Psophocarpus tetragonolobus (L) DC.], and seeds of Erythrina species.

Acacia↗
PubMed1993

Entamoeba histolytica proteins modulate the respiratory burst potential by murine macrophages.

Reactive oxygen intermediates are important components of macrophage microbicidal mechanisms and pathogenesis of parasitic disease. The purpose of the present study was to investigate the effect of virulent Entamoeba histolytica (strain HM1-IMSS) on respiratory burst potential of macrophages. Pretreatment of elicited peritoneal macrophages (EPM) with crude soluble amoebic proteins from 1 to 6 hr was found to prime EPM for enhanced O2 and H2O2 release in response to phorbol myristate acetate (PMA) in a dose-dependent manner, whereas pretreatment with the same concentrations of the non-pathogenic E. histolytica-like Laredo strain was without priming effect. Low molecular weight (MW) amoebic proteins (27,000-67,000) purified by Sephacryl-200 column chromatography and subfractionated by diethylaminoethyl cellulose chromatography were 10-fold more potent than crude amoebic proteins in priming EPM for an enhanced respiratory burst potential. Both crude and purified amoebic proteins inhibited the priming effect of lipopolysaccharide (LPS) or interferon-gamma (IFN-gamma) and antagonized the stimulating effect of PMA. Amoebic proteins by themselves were incapable of stimulating EPM respiratory burst. These findings demonstrate that amoebic proteins are capable of modulating the respiratory burst response of macrophages, suggesting an important role for them in the immunoregulation and pathogenesis of amoebiasis.

Animals↗
PubMed1993

Diagnoses after laparotomy for a mass in the pelvic area in women.

The management and outcome of 80 women with an undiagnosed pelvic mass who were referred to the Gynecologic Oncology Division at the University of Rochester during a one year period were reviewed. All patients underwent an exploratory laparotomy for definitive diagnosis. We correlated the final diagnosis with the results of preoperative evaluation and intraoperative assessment. Of the 80 patients, 48 were diagnosed with malignant disease. Of patients with carcinoma, 32 had carcinoma of the ovaries, two had other gynecologic malignancies, ten had nongynecologic malignancies and four had synchronous gynecologic and nongynecologic carcinomas. Carcinoma of the colon and rectum was the most common nongynecologic carcinoma; other malignant diseases were found in the endometrium, vagina, colon and rectum and the breast as well as lymphoma. Preoperative roentgenographic examinations and colonoscopy only had a sensitivity of 38 percent in detecting primary carcinoma of the colon and rectum. Ultrasound of the pelvic region and computed tomographic scan of the abdomen did not improve prediction of malignant disease in the patient population. Serum CA 125 was elevated in 26 of 37 patients with a carcinoma; however, it was elevated with relatively equal frequency in carcinomas of the ovaries and colon and rectum. Intraoperative frozen section accurately identified the primary site of the disease in 90 percent of the patients. However, in the presence of a tumor in the ovaries, carcinomatosis and a tumor in the colon, the results of frozen section were erroneous in four of six patients. Because preoperative assessment seems to be of limited value in excluding nongynecologic lesions, we recommend that pelvic surgeons be prepared to manage operatively a variety of malignant disease or have appropriate consultation available at laparotomy.

Adult↗
PubMed1992

Defining the carbohydrate specificities of Abrus precatorius agglutinin as T (Gal beta 1----3GalNAc) greater than I/II (Gal beta 1----3/4GlcNAc).

The combining site of the nontoxic carbohydrate binding protein (Abrus precatorius agglutinin, APA) purified from the needs of Abrus precatorius (Jequirity bean), was studied by quantitative precipitin and precipitin-inhibition assays. Of 26 glycoproteins and polysaccharides tested, all, except sialic acid-containing glycoproteins and desialized ovine salivary glycoproteins, reacted strongly with the lectin, and precipitated over 70% of the lectin added, indicating that APA has a broad range of affinity and recognizes (internal) Gal beta 1----sequences of carbohydrate chains. The strong reaction with desialized porcine and rat salivary glycoproteins as well as pneumococcus type XIV polysaccharide suggests that APA has affinity for one or more of the following carbohydrate sequences: Thomsen-Friedenreich (T, Gal beta 1----3GalNAc), blood group precursor type I and/or type II (Gal beta 1----3/4GlcNAc) disaccharide determinants of complex carbohydrates. Among the oligosaccharides tested, the T structure was the best inhibitor; it was 2.4 and 3.2 times more active than type II and type I sequences, respectively. The blood group I Ma-active trisaccharide, Gal beta 1----4GlcNAc beta 1----6Gal, was about as active as the corresponding disaccharide (II). From the above results, we conclude that the size of the combining site of the A. precatorius agglutinin is probably as large as a disaccharide and most strongly complementary to the Gal beta 1----3GalNAc (T determinant) sequence. The carbohydrate specificities of this lectin will be further investigated once the related oligosaccharide structures become available.

Binding, Competitive↗
PubMed1992

Low calcium/high magnesium medium increases activities of hypothalamic arcuate and suprachiasmatic neurons in brain tissue slices.

Extracellular single-unit recording was conducted in hypothalamic arcuate (ARC) and suprachiasmatic nucleus (SCN) in rat brain slices. The perifusion medium was switched from normal artificial cerebrospinal fluid (ACSF) to ACSF containing low Ca2+ and high Mg2+ to test the effect of extracellular calcium on the spontaneous activities of these neurons and their responses to some test agents. It was found that almost all of the ARC and SCN units tested increased their firing rates in low Ca2+, high Mg2+ ACSF, and exhibited more significant responses to excitatory test agents. The effects of low Ca2+, high Mg2+ ACSF were repeatable and reversible. The results suggest that extracellular Ca2+ is essential in maintaining the membrane stability of most hypothalamic neurons and most agents tested are acting postsynaptically on the unit recorded.

Action Potentials↗
PubMed1992

The complete primary structure of abrin-a B chain.

The complete 267 amino acid sequence of abrin-a B chain was determined by analysis of peptides obtained by digestion with trypsin, chymotrypsin, lysyl endopeptidase, Staphylococcus aureus V8 protease and thermolysin. The sequence is not identical with that predicted previously by nucleotide sequencing, indicating the presence of isoforms of abrin. Comparison of the amino acid sequence of abrin-a B chain with that of ricin-D B chain reveals a high degree of sequence identity (59%). Abrin-a B chain appears to consist of two domains, each domain with subdomains (alpha, beta, gamma) of about 40 amino acid residues.

Abrin↗
PubMed1992

Macrophage cytotoxicity against Entamoeba histolytica trophozoites is mediated by nitric oxide from L-arginine.

The killing of Entamoeba histolytica trophozoites by phagocytes involves oxidative and nonoxidative mediators. In this study, we determine whether L-arginine-derived nitric oxide (NO) is involved in the killing of E. histolytica trophozoites by activated murine macrophages in vitro. Elicited peritoneal and bone marrow-derived macrophages activated with IFN-gamma alone or with IFN-gamma and LPS killed 62 to 73% of amebae, concomitant with increased levels of nitrate (NO2). Depletion of L-arginine by addition of arginase to culture medium abrogated macrophage amebicidal activity. NG-monomethyl L-arginine, an L-arginine analog, competitively inhibited NO2 release and amebicidal activity in a dose-dependent fashion, without affecting H2O2 production; however, the addition of excess L-arginine competitively restored macrophage amebicidal effects. In culture, sodium nitrite and sodium nitroprusside were cytotoxic to E. histolytica and this was reversed by the addition of myoglobin. Exogenously added FeSO4 prevented macrophage cytotoxicity. Addition of superoxide dismutase, a scavenger of O2-, partially inhibited amebicidal activity, without influencing NO2 production. Untreated and LPS-exposed macrophages produced high levels of H2O2 independent from NO2 production and amebicidal effects. However, the addition of catalase, a scavenger of H2O2, inhibited both amebicidal activity and NO2 production by activated macrophages. Our results demonstrate that NO is the major cytotoxic molecule released by activated macrophages for the in vitro cytotoxicity of E. histolytica and that O2- and H2O2 may be cofactors for the NO effector molecule.

Animals↗
PubMed1992

Nucleotide sequence of cDNA for Acacia confusa trypsin inhibitor and implication of post-translation processing.

Synthetic oligonucleotides corresponding to all possible sequences of N-terminal and C-terminal region of Acacia confusa trypsin inhibitor were used to generate ACTI-related sequences using the polymerase chain reaction on the cDNAs encoding ACTI of the seeds of legume, A. confusa. The deduced amino acid sequence agreed with that determined by the peptide analysis except an extra amino acid residue, serine, was found at the junction of A and B chain, which was removed by post-translation processing with specific protease(s). The substrate specificity of the protease(s) was found to cleave at the C-terminal sites of asparagine and serine, which was also shown to be the same case for another plant protein, abrin, isolated from legume, Abrus precatorius.

Acacia↗
PubMed1992

Clinical presentation and management of stage I cervical adenocarcinoma: a 25 year experience.

In this study, we review the clinical presentation, treatment, and prognosis of 89 patients with stage I cervical adenocarcinoma treated at Strong Memorial Hospital over the past 25 years. In the past decade, the mean age of patients with stage I cervical adenocarcinoma was 44 years, in contrast to a mean of 58 years in the prior interval (P less than 0.001). Prior to 1980 only 4% of patients were of childbearing age, whereas in the past decade 27% were under 35 years old (P = 0.02). The difference in age at presentation cannot be explained by earlier detection, as the fraction of stage I patients, the mean tumor size, and the percentage of clinically occult tumors have not changed. There were no ovarian metastases in 41 patients who underwent oophorectomy. Adenosquamous tumours did not differ in prognosis from pure adenocarcinoma. Grade and lymph node status were significant predictors of outcome. Treatment results have not improved over the past 25 years, and combined therapy with radiation and surgery offered no advantage over radiation alone. Because this tumor is more frequently seen in younger patients, the management of occult adenocarcinoma with early stromal invasion has become problematic. Ovarian conservation has been questioned, and the lack of generally accepted criteria for microinvasive adenocarcinoma has led to radical therapy in patients who might have been adequately treated with local excision. Further study is necessary to guide our recommendations regarding preservation of ovarian function or even childbearing potential in young women.

Adenocarcinoma↗
PubMed1992

Morbidity and recurrence with modifications of radical vulvectomy and groin dissection.

Vulvar carcinoma has been managed in recent years with modifications of radical vulvectomy and groin dissection. Separate groin incisions, superficial inguinal lymphadenectomy, unilateral groin dissection, and wide excision have been utilized to reduce the morbidity of treatment. In this study, the surgical management of 82 patients with vulvar squamous cell carcinoma was reviewed in order to assess morbidity and risk of recurrence. A modification of radical vulvectomy and groin dissection was employed in 67 patients, while 15 patients underwent classical en-bloc vulvar and groin dissection. Wound complications of the vulva occurred in 1 of 12 patients undergoing hemivulvectomy, in 8 of 55 undergoing radical vulvectomy, and in 7 of 15 who had en-bloc vulvar resection and groin dissection (P = 0.01). Among the 46 patients undergoing bilateral groin dissection through separate incisions, groin breakdown, lymphocyst, and lymphedema occurred in 10 (22%), 7 (15%), and 7 (15%), versus 0, 1 (7%), and 2 (13%) of the 15 who had unilateral groin dissection. Modification of vulvar resection did not increase the risk of local recurrence. Groin recurrence developed in 2 of 15 patients who underwent en-bloc groin dissection and in 1 of 46 who underwent bilateral groin dissection through separate incisions. Two of 15 who had a unilateral groin dissection recurred in the contralateral groin. The risk of recurrence as well as morbidity following modifications of radical vulvectomy with groin dissection should be considered when planning treatment.

Aged↗
PubMed1992

Inhibition of Moloney murine leukemia virus reverse transcriptase activity by tetrahydroxyxanthones isolated from the Chinese herb, Tripterospermum lanceolatum (Hyata).

Five tetrahydroxyxanthones (THXs) isolated from Tripterospermum lanceolatum (Hyata) have been shown to have a strong inhibitory effect on Moloney murine leukemia virus reverse transcriptase (Mo-MLV RT) activity when (rA)n-(dT)15 and (rC)n-(dT)12-18 were used as template-primers. 50% inhibitory concentrations of 1,3,5,6-THX, 2,3,6,7-THX 1,3,6,7-THX, 3,4,5,6-THX, and 3,4,6,7-THX were determined to be 0.15, 0.27, 0.58, 0.12, and 0.12 microM, respectively. Their effects were concentration-dependent, and the mode of inhibition was found to be by competitive inhibition with respect to template-primer. The tetrahydroxyl groups of THXs were shown to be important for their inhibitory activity. Acylation of THXs with various groups resulted in a moderate or strong decrease in their inhibitory activity.

Acylation↗
PubMed1992

Inhibitory effects of flavonoids on Moloney murine leukemia virus reverse transcriptase activity.

Several flavonoids were tested for their effects on Moloney murine leukemia virus reverse transcriptase activity. Four groups of flavonoids, namely flavones, flavanones, flavonols, and flavanonols, were studied, and it was found that flavonols and flavanonols were very active in this regard while flavones and flavanones displayed very low activity. Among the flavonoids tested, fisetin, quercetin, myricetin, kaempferol, morin, (+/-)-taxifolin, (+)-catechin, and (-)-epicatechin were shown to be highly effective in inhibiting the reverse transcriptase activity. Structure-activity relationship analysis of these flavonoids revealed that the simultaneous presence of free hydroxyl groups at positions 3 and 4' enhanced the reverse transcriptase inhibitory activity. Replacement of the 3-hydroxyl group with a monosaccharide or of the 4'-hydroxyl group with a methyl group reduced inhibitory activity. The double bond at position 2 and 3 of the flavonoid's pyrone ring is not essential for inhibiting reverse transcriptase activity. The flavonoids studied demonstrated ability to inhibit the reverse transcriptase activity using either (rA)n(dT)12-18 or (rC)n(dG)12-18 as template-primers.

DNA Polymerase I↗
PubMed1992

Inhibition of angiotensin-I-converting enzyme by tetrahydroxyxanthones isolated from Tripterospermum lanceolatum.

Five tetrahydroxyxanthones, 3,4,6,7-tetrahydroxyxanthone [1], 1,3,5,6-tetrahydroxyxanthone [2], 3,4,5,6-tetrahydroxyxanthone [3], 1,3,6,7-tetrahydroxyxanthone [4], and 2,3,6,7-tetrahydroxyxanthone [5] isolated from Tripterospermum lanceolatum inhibited angiotensin-I-converting-enzyme activity in a dose-dependent manner. The mode of inhibition of the tetrahydroxyxanthones (THXs) was found to be competitive inhibition. When the tetrahydroxy groups of THXs were blocked with acetyl groups, the angiotensin-I-converting-enzyme inhibitory activity was abolished, suggesting that the tetrahydroxy groups are indispensible for the inhibitory activity.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

The young pioneers: first baccalaureate nursing students in the People's Republic of China.

Nursing in the People's Republic of China, like elsewhere, has undergone monumental changes during the 20th century. This paper focuses on one of those changes by examining the professional socialization process of the first class from the first baccalaureate in nursing (BSN) programme in China since 1952. These data from this first BSN class are part of a larger study on professional socialization in which data were collected from four of the recently established 11 BSN programmes in China. To put these data into a historical context, some highlights of Chinese nursing history are noted. These will help us to understand the present-day situation in this the world's most populous nation.

Adult↗