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Biomedical subjects

L Lee

Publications and source records attributed to L Lee.

At least 289 records · Page 16Linked to original sources
PubMed1988

Percutaneous transluminal coronary angioplasty improves survival in acute myocardial infarction complicated by cardiogenic shock.

Modest survival benefits have been reported in patients with acute myocardial infarction complicated by cardiogenic shock who were treated with early surgical revascularization or thrombolytic therapy. To determine whether coronary angioplasty improves survival, 87 patients with cardiogenic shock complicating acute myocardial infarction at the University of Michigan, Ann Arbor, Michigan, from 1975 to 1985 were retrospectively analyzed. Patients in group 1 (n = 59) were treated with conventional therapy; patients in group 2 (n = 24) were treated with conventional therapy and angioplasty. Extent of coronary artery disease, infarct location, and incidence of multivessel disease were similar between groups. Hemodynamic variables including cardiac index, mean arterial pressure, and pulmonary capillary wedge pressure were also similar. The 30-day survival was significantly improved for group 2 patients (50% vs. 17%, p = 0.006). Survival in group 2 patients with successful angioplasty was 77% (10 of 13 patients) versus 18% (two of 11 patients) in patients with unsuccessful angioplasty, (p = 0.006). The findings suggest that angioplasty improves survival in cardiogenic shock compared with conventional therapy with survival contingent upon successful reperfusion of the infarct-related artery.

Angioplasty, Balloon↗
PubMed1988

The insulin-like growth factor II/mannose-6-phosphate receptor is present in monkey serum.

We recently reported that the insulin-like growth factor II (IGF-II)/mannose-6-phosphate (Man-6-P) receptor is present in fetal and postnatal rat serum and that its serum content declined dramatically postnatally between days 20 and 40 . We now provide evidence that the IGF-II/Man-6-P receptor is also present in monkey serum. Serum was gel filtered on Sephadex G-200, and the column fractions were assayed for binding of radiolabeled IGF-II. There was significant binding of [125I]IGF-II to the void volume fractions in addition to binding to the 150K and 40K carrier proteins. Binding to the void volume fractions was greatest in cord serum and decreased with age. Competitive binding studies with [125I]IGF-II and the void volume pools from monkey serum demonstrated that IGF-I competed less potently than IGF-II, and insulin did not compete. Radiolabeled IGF-I did not bind specifically to the void volume pools. Chemical cross-linking of [125I]IGF-II to aliquots of the void volume pools from monkey cord serum samples and analysis with sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of dithiothreitol demonstrated a specific band at about 240K. Western blotting using a specific antiserum (no. 3637) against rat IGF-II/Man-6-P receptor was performed on aliquots of the Sephadex G-200 void volume pools of monkey serum. A band of approximately the same size as that found with human fibroblast members (approximately 215 K without dithiothreitol) was detected. The IGF-II/Man-6-P receptor band was more intense in cord serum than in the postnatal samples. When cord serum Sephadex G-200 pools were gel filtered on Sephadex G-50 in 1 mol/L acetic acid to separate binding components from free IGF, and IGF-II was measured by RRA, approximately 20% of the circulating IGF-II was found to be associated with this IGF-II/Man-6-P receptor in monkey serum. We conclude that the IGF-II/Man-6-P receptor present in serum may be a significant carrier for IGF-II in the monkey.

Aging↗
PubMed1987

An antibody that blocks insulin-like growth factor (IGF) binding to the type II IGF receptor is neither an agonist nor an inhibitor of IGF-stimulated biologic responses in L6 myoblasts.

To better define the biologic function of the type II insulin-like growth factor (IGF) receptor, we raised a blocking antiserum in a rabbit by immunizing with highly purified rat type II IGF receptor. On immunoblots of crude type II receptor preparations, only bands corresponding to the type II IGF receptor were seen with IgG 3637, indicating that the antiserum was specific for the type II receptor. Competitive binding and chemical cross-linking experiments showed that IgG 3637 blocked binding of 125I-IGF-II to the rat type II IGF receptor, but did not block binding of 125I-IGF-I to the type I IGF receptor, nor did IgG 3637 block binding of 125I-insulin to the insulin receptor. In addition, IgG 3637 did not inhibit the binding of 125I-IGF-II to partially purified 150- and 40-kDa IGF carrier proteins from adult and fetal rat serum. L6 myoblasts have both type I and type II IGF receptors. IGF-I was more potent than IGF-II in stimulating N-methyl-alpha-[14C]aminoisobutyric acid uptake, 2-[3H]deoxyglucose uptake, and [3H]leucine incorporation into cellular proteins. IgG 3637 did not stimulate either 2-[3H]deoxyglucose uptake, N-methyl-alpha-[14C]aminoisobutyric acid uptake, or [3H]leucine incorporation into protein when tested alone. Furthermore, IgG 3637 at concentrations sufficient to block type II receptors under conditions of the uptake and incorporation experiments did not cause a shift to the right of the dose-response curve for stimulation of these biologic functions by IGF-II. We conclude that the type II IGF receptor does not mediate IGF stimulation of N-methyl-alpha-[14C]aminoisobutyric acid and 2-[3H]deoxyglucose uptake and protein synthesis in L6 myoblasts; presumably, the type I receptor mediates these biologic responses. The anti-type II receptor antibody inhibited IGF-II degradation in the media by greater than 90%, suggesting that the major degradative pathway for IGF-II in L6 myoblasts utilizes the type II IGF receptor.

Animals↗
PubMed1987

Induction of penile erection by intracavernosal injection: a double-blind comparison of phenoxybenzamine versus papaverine-phentolamine versus saline.

Recent data suggest that intracavernous injections of phenoxybenzamine in saline, and/or papaverine with phentolamine mesylate in saline, result in erection in otherwise impotent men. A double-blind study using normal saline and normal saline mixed with phenoxybenzamine or papaverine-phenotolamine mesylate showed that none of 11 subjects with organic erection dysfunction responded with appreciable penile swelling to saline injection, but all responded with some degree of penile swelling to the other solutions. The mechanism of penile erection in response to intracavernous injections is still unclear, but it is thought to be related to the alpha-adrenergic blocking and/or smooth muscle relaxant actions of these drugs; the volume of the injection or the normal saline content of the solution are not factors in causing penile tumescence.

Adult↗
PubMed1987

Retinitis pigmentosa with segmental massive retinal gliosis. An immunohistochemical, biochemical, and ultrastructural study.

A morphologic, immunohistologic, and biochemical study was made on the eyes of a 79-year-old woman with clinically documented retinitis pigmentosa (RP). The methods included light and electron microscopy, immunohistologic staining, and biochemical analysis of interphotoreceptor retinoid-binding protein (IRBP) and cyclic nucleotides. Results from a histopathologic examination showed marked equatorial pigmentary retinal degeneration as well as peripheral chorioretinal atrophy corresponding to areas of paving stone chorioretinal changes. An unusual finding was a localized equatorial nodule in the right eye that stained with anti-glial fibrillary acidic protein (GFAP) antibodies, and showed lipid infiltrates in its margin and base. The equatorial retina showed marked gliosis of the outer layers. Photoreceptor cells were present only in the posterior retina, macula, and focally, in the far periphery. These areas corresponded to detectable IRBP assessed by immunohistochemical staining and biochemical analysis using the enzyme-linked immunosorbent assay (ELISA). Cyclic nucleotides were reduced in the peripheral retina, in areas of photoreceptor cell loss.

Aged↗
PubMed1987

Type II insulin-like growth factor receptor is present in rat serum.

We previously identified in fetal rat serum a component capable of specifically binding radiolabeled insulin-like growth factor type II (IGF-II) that is considerably larger than both the fetal (40 kDa) and the adult (150 kDa) carrier proteins. We now present immunologic and affinity crosslinking data to show that this binding species is the type II IGF receptor. Rat serum was gel-filtered on a Sephadex G-200 column (0.05 M NH4HCO3, pH 8), and 125I-labeled IGF-II (125I-IGF-II) binding was measured in individual column fractions. 125I-IGF-II binding activity was found in the void volume of the column in addition to the carrier protein regions. Competitive binding studies using 125I-IGF-II and binding activity from the Sephadex G-200 void volume showed the characteristics of the type II receptor: IGF-II was more potent than IGF-I, and insulin did not compete. Moreover, a specific anti-type II IGF receptor antibody (no. 3637) completely blocked 125I-IGF-II binding. 125I-IGF-I did not bind to the void volume pool, demonstrating the absence of the type I IGF receptor in rat serum. Affinity crosslinking of 125I-IGF-II to the Sephadex G-200 void volume material demonstrated a specific band at 210 kDa without reduction and at 240 kDa after reduction of disulfide bonds. The serum type II IGF receptor size was confirmed by immunoblotting the void volume material with antiserum 3637, which revealed a band slightly smaller (approximately 10 kDa) than the type II IGF receptor from rat placental membranes. Immunoquantitation by immunoblotting using pure type II IGF receptor from rat placental membranes as standard showed a developmental pattern. In fetal rat serum (19-days gestation) and in sera from 3-, 10-, and 20-day-old rats, the concentrations of receptor protein were similar (1-5 micrograms/ml). The level of the type II IGF receptor in serum declined dramatically between age 20 and 40 days, but the receptor was still measurable at age 12 mo. We conclude that the type II IGF receptor is present in rat serum and is developmentally regulated.

Animals↗
PubMed1987

Construction and Homologous Expression of a Maize Adh1 Based NcoI Cassette Vector.

The alcohol dehydrogenase I (Adh1) gene of maize (Zea mays L.) was employed as a source of transcriptional, posttranscriptional, and translational regulatory sequences in the construction of an expression vector. By transforming the translation-initiating ATG and an ATG three triplets upstream from the translational termination triplet into NcoI sites (5'-CCATGG-3'), the maize Adh1 gene was converted into a cassette vector allowing one-step placement of any structural gene under Adh1 regulatory control. We inserted the structural gene for chloramphenicol acetyl transferase (CAT) into this cassette vector and found that this construct expressed the cat gene when transfected into maize protoplasts. Significant expression was observed with a construct that contained only 146 base pairs of Adh1 sequence upstream of the transcription-initiation site. Derivatives with a further 266 or 955 base pairs of contiguous Adh1 upstream sequences increased CAT expression approximately 5-fold or 8-fold, respectively.

Journal Article↗
PubMed1987

Neonatal hypertrophic cardiomyopathy: a case report and family study.

An infant of a diabetic mother is described with severe neonatal hypertrophic obstructive cardiomyopathy. Commencement of regular intravenous propranolol was associated with marked clinical improvement. Long-term oral propranolol was continued and at 12 months of age there was complete resolution of the cardiomyopathy. Familial hypertrophic cardiomyopathy hypertrophy was present in two other generations of this family. The results of family screening and tissue typing are presented, with the suggestion that tissue typing may be a useful tool in the assessment of doubtful cases in certain affected families.

Adult↗
PubMed1987

IRBP from bovine retina is poorly uveitogenic in guinea pigs and is identical to A-antigen.

Retinal interphotoreceptor retinoid-binding protein (IRBP) is a potent uveitogen in Lewis rats, producing experimental autoimmune uveitis (EAU) reproducibly at doses lower than those of S-antigen (S-Ag). In contrast, IRBP was found to be poorly uveitogenic in three strains of guinea pigs, inducing only minor changes in a small proportion of these animals. On the other hand, S-Ag was found to induce EAU in the majority of immunized guinea pigs, with changes more severe than those induced by IRBP. Unlike the difference in their uveitogenicity, IRBP and S-Ag induced similar levels of specific immune responses in the immunized guinea pigs. The poor uveitogenicity of IRBP in guinea pigs resembles that of A-antigen (A-Ag). The two proteins are also similar in other features and were found in this study to be antigenically identical. It is proposed that IRBP and A-Ag are one and the same protein.

Animals↗
PubMed1987

Quaternary structure of intestinal maltase-glucoamylase in pancreatectomized rats.

Detergent-solubilized intestinal maltase-glucoamylase was isolated 1 week postpancreatectomy (dMpanc) and purified in the presence of detergent and protease inhibitors. Upon sodium dodecyl sulfate - polyacrylamide gel electrophoresis under nondissociating conditions, the major band had a molecular weight of 280,000, slightly smaller than similar bands from detergent (dM) and papain (pM) solubilized maltase from nonpancreatectomized rats. Upon octyl-Sepharose CL-4B chromatography, 57% of the enzyme was eluted by aqueous buffer, unlike pM which was almost completely eluted or dM, 95% of which bound to the column. All fractions of dMpanic from octyl-Sepharose 4B were reduced, by boiling +/- beta-mercaptoethanol, to monomeric subunits, indicating that processing by pancreatic enzymes at the level of the brush border is not a requirement for the appearance of subunits in the rat. As well, under these dissociating conditions, the 145,000 subunit previously identified with the apolar terminus was present in all fractions of dMpanc, including the aqueous fraction, whereas pM contained only the 130,000 subunit. The presence of dMpanc in the aqueous fraction cannot be explained, therefore, by proteolytic cleavage of an apolar anchor segment from the 145,000 subunit. Pancreatic enzymes may affect the enzyme in a minor fashion, however, since aqueous solubility was enhanced and the apparent molecular weight was reduced by pancreatectomy, suggesting a more compact conformation with shielding of apolar segments.

Animals↗
PubMed1986

Effect of ethanol on receptor-stimulated phosphatidic acid and polyphosphoinositide metabolism in mouse brain.

The effects of chronic ethanol consumption as well as the effects of ethanol added in vitro on phosphoinositide metabolism were determined in mouse forebrain. [32P] incorporation into synaptosomal phosphatidic acid (PhA) was stimulated through both M1 muscarinic cholinergic and alpha 1 adrenergic receptor activation. Similarly, [3H]inositol 1-PO4 accumulation in brain slices was stimulated through these same receptors, but could also be stimulated by histamine1 receptor activation. In mice made physically dependent to ethanol, the magnitude of receptor-mediated [32P] incorporation in PhA did not differ from that of control animals. However, ethanol (100mM) added in vitro to synaptosomes from control mice significantly inhibited the carbamylcholine stimulated PhA response, but had no effect on the response to norepinephrine. Carbamylcholine stimulated [32P] incorporation into PhA, however, was no longer significantly inhibited by the addition of 100mM ethanol to synaptosomes from physically dependent-tolerant animals indicating that a cellular tolerance had developed. In contrast, receptor mediated [3H]inositol 1-PO4 accumulation in brain slices was not significantly affected by either chronic ethanol treatment or the in vitro addition of ethanol as high as 200mM. It is concluded that the muscarinic cholinergic stimulation of [32P] incorporation into PhA, but not [3H]inositol 1-PO4 accumulation is relatively more sensitive to the direct effects of ethanol than are the other receptor mediated phospholipid responses examined in the present investigation and that this sensitivity is lost in animals made behaviorally tolerant and physically dependent to ethanol.

Animals↗
PubMed1986

Herpes simplex virus expressing Epstein-Barr virus nuclear antigen 1.

DNA fragments containing an open reading frame known to encode most or all of the EBNA1 protein of Epstein-Barr virus (EBV) were fused in the proper transcriptional orientation to the promoter regulatory domain, capping site, and a portion of the 5' transcribed noncoding sequences of the HSV-1 alpha 4 gene of herpes simplex virus 1 (HSV-1). In these constructs 20, 130, or 385 bp of EBV DNA and 28 bp of HSV-1 DNA separated the alpha 4 cap site from a putative initiator codon of the EBNA1 gene. The chimeric alpha 4-EBNA1 genes were introduced into L cells or recombined into the viral genome using the thymidine kinase selection system. The three chimeric gene constructs resident in the L cell clones expressed a protein indistinguishable from authentic EBNA1 with respect to electrophoretic and immunologic properties indicating that the ATG at the beginning of the EBV open reading frame initiated translation of the bonafide EBNA1 protein. The chimeric alpha 4-EBNA1 genes resident in L cells were induced by HSV-1 infection and were regulated as alpha genes. The chimeric alpha 4-EBNA1 gene recombined into the viral genome was also regulated as an alpha gene. The recombinant viruses were stable and expressed 50- to 100-fold more EBNA1 than is ordinarily expressed in human lymphocytes carrying the EBV genome. EBNA1 did not alter the program of HSV-1 protein expression. The utility of the vector is discussed.

Animals↗
PubMed1986

African sleeping sickness presenting in an American emergency department.

A 27-year-old American man who had returned recently from East Africa presented with African sleeping sickness, probably of the Rhodesian (East African) type. High fever, malaise, and watery diarrhea were his predominant symptoms. No trypanosomal chancre was noted. Treatment for malaria in Africa had not been effective. In the emergency department, diagnosis was established by demonstrating trypanosomes on blood smear. Treatment with an IV course of Suramin was successful.

Adult↗