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Biomedical subjects

H Lee

Publications and source records attributed to H Lee.

At least 829 records · Page 46Linked to original sources
PubMed1984

Transfer of language dominance.

It has been suggested that recovery from aphasia may depend on the ability of the nondominant hemisphere to subserve language functions. We describe a patient who illustrates a possible "transfer" of language dominance. The patients sustained two infarcts two years apart, one in each hemisphere, involving mirror image territories in the temporoparietal area. The clinical course of each infarct was almost identical, consisting of an initial Wernicke's aphasia which evolved into anomic aphasia during recovery.

Anomia↗
PubMed1984

Estrogen induction of progestophilins in rat estrogen-sensitive cells grown in media supplemented with sera from castrated rats and from rats bearing an alpha-fetoprotein-secreting hepatoma.

The purpose of this work was to study the effect of alpha-fetoprotein (AFP) over cell multiplication and the induction of an estradiol-17 beta (E2)-dependent marker, i.e., progestophilins in E-sensitive cells C2(9)RAP derived from a W/Fu rat pituitary tumor. These cells proliferate in isogeneic hosts under the influence of E2, while they proliferate in culture regardless of the presence of E2. C2(9)RAP cells were grown in medium supplemented with 10% horse serum. Progestophilin levels were measured 48 h after adding serum (20% horse, or castrated rat, or AFP-secreting tumor-bearing rat) and estrogen to the 10% horse serum-supplemented medium in which the cells were growing. Maximal induction of progestophilins was obtained at 3 X 10(-10) M E2 in cells grown in medium containing horse or castrated rat serum. In contrast, maximal induction of progestophilins required 3 X 10(-8) M E2 in cells grown in medium supplemented with the serum of Morris hepatoma 7777-bearing rats. This serum contained AFP levels comparable to those present at birth in the rat. 11-Methoxy-17 beta ethynylestradiol (R2858), a synthetic estrogen with little affinity for AFP, was also tested for its ability to induce progestophilins. The degree of maximal induction of progestophilins expressed as percentage of the respective control, was similar for all experimental groups, both with E2 and with R2858. In addition, we compared the free E2 levels in the culture medium with the progestophilin levels and the cell proliferation rate. We found that the progestophilin levels were maximal at free E2 concentrations above 11 pg E2/ml, whereas there was no correlation between the free E2 levels and the proliferation rate. Moreover, the proliferation rate of cells in medium supplemented with horse or castrated rat serum was maximal at concentrations of free E2 below 0.4 pg/ml; whereas cell proliferation was inhibited with hepatoma serum even at concentrations of free E2 of 44 pg/ml. We conclude that the effect of hepatoma serum on the E2 induction of progestophilins seems to be mediated by the effect of AFP on the availability of free estrogen, since it is abolished by the addition of both natural and synthetic estrogens. The inhibitory effect of hepatoma serum upon cell proliferation is not reversed by estrogens and thus seems to be mediated by mechanisms other than E2 trapping by AFP.

Animals↗
PubMed1984

Radiation therapy of conjunctival and orbital lymphoid tumors.

Lymphoid tumors of the conjunctiva and orbit are rare and remain localized in the majority of cases. Sometimes it is not possible either clinically or histologically to differentiate between a non-Hodgkin's lymphoma (NHL) and benign lymphoid hyperplasia. A series of 24 patients is reported. Nineteen were classified as having malignant NHL and 5 benign hyperplasia; 1 of these 5 later developed metastases, however. All patients had systemic work-up: 18 had Stage I, 1 had Stage II, and 5 had Stage IV disease. All patients received local radiation therapy with doses of 2400 to 2750 rad in 2-3 weeks for lesions of the eyelid and conjunctiva, and between 3000 and 3750 rad in 3-4 weeks for retrobulbar lesions. The lens was shielded in all patients except in 2 who had NHL of the vitreous body. A method of shielding the lens with a lead block mounted on a "low vac lens" is described, and the dose distribution within the eye and orbit is presented. The dose to the ocular lens is reduced to about 10% of the tumor dose with this technique. Patients who were treated with doses higher than 3000 rad experienced conjunctivitis and skin erythema that resolved completely. No other effects of radiation on normal structures of the ocular adnexa were observed in the 20 patients who are alive and without signs of tumor 10-46 months with a median follow-up time of 22 months.

Adolescent↗
PubMed1984

Cellular ADP-ribosyltransferase with the same mechanism of action as diphtheria toxin and Pseudomonas toxin A.

An ADP-ribosyltransferase was found in elongation factor 2 (EF-2) preparations from polyoma virus-transformed baby hamster kidney (pyBHK) cells. Like fragment A of diphtheria toxin and Pseudomonas toxin A, this eukaryotic cellular enzyme transfers [14C]adenosine from NAD+ to EF-2. However, the cellular transferase is immunologically distinct from fragment A. The transferase also can be distinguished from fragment A and Pseudomonas toxin A by the inhibition of the activity of the former by cytoplasmic extracts and by histamine. Snake venom phosphodiesterase digestion of the [14C]adenosine-labeled EF-2 product of the cellular transferase reaction yielded [14C]AMP, indicating that the cellular enzyme is a mono(ADP-ribosyl)transferase. The forward ADP-ribosylation reaction catalyzed by the cellular enzyme is reversed by fragment A, yielding [14C]NAD+. The results strongly suggest that the cellular transferase is a mono(ADP-ribosyl)transferase, which ADP-ribosylates the same diphthamide residue of EF-2 as does fragment A and Pseudomonas toxin A.

ADP Ribose Transferases↗
PubMed1984

A method for exposing the internal anatomy of small and delicate tissues for correlated SEM/TEM studies using polyethylene glycol embedding.

A method for preparing and handling large, clean, distortion-free cut surfaces through small and delicate tissues for correlated SEM/TEM examination is described. In this method, tissues are fixed according to conventional protocols; however, instead of critical-point-drying after fixation, tissues are first embedded in polyethylene glycol (PEG), a water-soluble waxy solid. Tissue blocks are easily oriented and sectioned to the desired regions, immersed in a solvent to remove PEG, critical-point-dried, and examined with an SEM. The same tissue blocks can be reworked for TEM by immersing in propylene oxide and embedding in an epoxy resin.

Animals↗
PubMed1984

Sustained upgaze in coma.

Sustained upgaze is a rare phenomenon that is observed primarily in those patients with coma secondary to cardiac arrest or prolonged hypotension. Because of "selective vulnerability" of the brain, cardiac arrest or prolonged hypotension may produce both cerebral and cerebellar cortical damage sparing the brain stem vestibulo-ocular reflex (VOR) pathways. This selective damage may be responsible for the generation of sustained upgaze. The VORs receive their selective inhibition from the cerebellar flocculus. This inhibition is exerted on only one of the two VOR pathways converging on each extra-ocular muscle, so that total disinhibition of the VOR pathway activities will result in a tonic upward bias. The underlying neuronal mechanism of sustained upgaze appears to be due to total floccular disinhibition resulting in upward drift produced by the biased VOR and the lack of correcting saccades due to cerebral dysfunction releasing the brain stem ocular motor systems from their control.

Cerebellar Cortex↗
PubMed1984

Anti-inflammatory adrenal steroids that neither inhibit skin collagen synthesis nor cause dermal atrophy.

Clinically used topical anti-inflammatory adrenal steroids inhibit skin collagen synthesis. This impaired collagen synthesis may result in dermal atrophy. Structure activity studies contrasted the effects of the novel prednisolone derivatives, methylprednisolonate , and methyl 20 dihydroprednisolonate , with presently used anti-inflammatory adrenal steroids on granuloma formation and skin collagen synthesis. These two new prednisolone derivatives, when applied locally at equivalent-potency anti-inflammatory doses compared with other corticosteroids, markedly inhibit granuloma formation but do not inhibit skin collagen synthesis nor cause dermal atrophy in rats. The data indicate that the two prednisolone acid methyl esters may be safer topical anti-inflammatory adrenal steroids to use, since they do not inhibit normal skin collagen synthesis.

Administration, Topical↗
PubMed1984

Epileptic Kluver-Bucy syndrome: case report.

The Kluver-Bucy syndrome (KBS) consists of prominent oral tendencies, emotional blunting, altered dietary habits, hypersexuality, and visual and auditory agnosia. It was first produced experimentally in monkeys; subsequently, many human cases have been reported. The syndrome results from bilateral temporal lobe damage, and is mainly observed in conditions which tend to produce such damage, such as herpes encephalitis, Pick disease, and head injury. A case of KBS associated with psychomotor status epilepticus is reported.

Agnosia↗
PubMed1984

Aerosol bag for administration of bronchodilators to young asthmatic children.

An aerosol rebreathing bag was developed by modifying an ordinary freezer bag of 1-qt size. A mouthpiece was inserted in a corner of the bag, and the aerosol canister was actuated inside the bag while an asthmatic child breathed in and out of the bag. Its feasibility was tested in 20 child-parent pairs. Children less than age 7 years easily learned to inhale aerosols from the bag. Bronchodilator efficacy of albuterol aerosol using the bag was compared with that of the canister mouthpiece in 15 children aged 7 to 15 years. The results were nearly identical.

Adolescent↗
PubMed1983

Carbocyclic arabinofuranosyladenine (cyclaradine): efficacy against genital herpes in guinea pigs.

Carbocyclic arabinofuranosyladenine (cyclaradine), a novel nucleoside analog with such desired features as hydrolytic and enzymatic stability, adenosine deaminase resistance, and low systemic toxicity, inhibited the replication of herpes simplex virus types 1 and 2. The 5'-methoxyacetate prodrug form exhibited significant efficacy in the topical treatment of genital infections by herpes simplex virus type 2.

Acyclovir↗
PubMed1983

Conformational states of N-acylglycine dithioesters in solution: resonance Raman studies of isotopically substituted models for enzyme-substrate complexes.

Resonance Raman (RR) and FTIR spectroscopic studies, taken with X-ray crystallographic data, are used to define the three major conformational states of N-acylglycine dithioesters in solution and to set up spectra-structure correlations. Importantly, each conformer has a characteristic RR signature, and thus the RR spectrum can be used to follow conformational events within dithioester enzyme-substrate intermediates. The signatures are further defined in the present work by the synthesis and spectroscopic characterization of 13C and 15N derivatives of N-benzoylglycine ethyl dithioester and N-(beta-phenylpropionyl)glycine ethyl dithioester. The observed isotope shifts offer insight into the normal mode character of the RR bands and provide standards with which to compare the shifts in the corresponding enzyme-substrate intermediates.

Enzymes↗
PubMed1983

Relaxed and perturbed substrate conformations in enzyme active sites: evidence from multichannel resonance raman spectra.

A diode array based multichannel Raman spectrometer has made it possible to record complete, high quality, resonance Raman (RR) spectra of enzyme-substrate intermediates. The intermediates are dithioacylpapains in which the acyl group is either N-benzoylglycine or N-(beta-phenylpropionyl)glycine. RR data are reported for the unlabeled dithioacylpapains as well as for the intermediates labeled separately with ND, 15N, and 13C = S in the glycine residue. Comparison of the results for the dithioacylpapains with that of the corresponding labeled glycine ethyl dithioesters [Lee, H., Storer, A. C., & Carey, P. R. (1983) Biochemistry (preceding paper in this issue)] leads to the conclusion that for both substrates in the active site the dihedral angles in the glycine NH-C-C(= S) linkages assume an essentially relaxed type B conformation. Similarly, there is no evidence for distortion about the C(= O)-NH peptide bond which links the P1 and P2 sites on the substrate. However, for the N-benzoylglycine case there is evidence for some conformational distortion in the -S-C-C cysteine linkages. The present data favor a single homogeneous conformational population about the substrates' NH-C-C(= S) bonds in the native dithioacylpapains. However, below pH 3.0 the dithioacyl enzymes denature and the RR spectra of the 13C = S substituted species confirm that the conformational population reverts to the mixture of conformers A and B found for the corresponding ethyl dithioesters in solution.

Binding Sites↗
PubMed1983

Purification and properties of an altered form of elongation factor 2 from mutant cells resistant to intoxication by diphtheria toxin.

Elongation factor 2 (EF-2) was isolated from wild-type and mutant-polyoma-virus-transformed baby hamster kidney cells resistant to intoxication by diphtheria toxin. Cells were grown as tumors in hamsters and EF-2 was purified from tissue homogenates by column chromatography. Both forms of EF-2 chromatograph identically in Whatman DE-52 DEAE-cellulose, Sephadex DEAE-A50 and Sephacryl S-200 resins. However, wild-type and the mutant form of EF-2 elute from phosphocellulose at 0.16 M and 0.24 M KCl respectively. Both forms of EF-2 migrate in sodium dodecyl sulfate/polyacrylamide gels as a single band with an Mr of 93000 and produce identical 125I-labeled tryptic peptide maps. However, additional labeled tryptic peptides are seen when wild-type EF-2 is ADP-ribosylated by fragment A diphtheria toxin. The purified mutant protein is totally resistant to ADP-ribosylation and cannot be transformed into an ADP-ribosylatable form in a posttranslational modification system in vitro, indicating that resistance to ADP-ribosylation results from a mutation in the structural gene for EF-2.

Adenosine Diphosphate Ribose↗
PubMed1983

Acquired immunodeficiency with reversed T4/T8 ratios in infants born to promiscuous and drug-addicted mothers.

A new syndrome of acquired immunodeficiency has been identified in seven children who were small for gestational age at birth and subsequently have exhibited failure to thrive, lymphadenopathy, parotitis, hepatosplenomegaly, interstitial pneumonia, and recurrent infections. All have a profound cell-mediated immunodeficiency with reversed T4/T8 ratios. Six are hypergammaglobulinemic and one has low IgG levels. The mothers of five of the seven children are sexually promiscuous and/or drug addicts. Three mothers have an immunodeficiency similar to that found in their infants. One of them died at age 33 years with a diagnosis of acquired immunodeficiency syndrome. In five of the children and in three of their mothers, there is evidence of a persistent Epstein-Barr virus (EBV) infection. We speculate that a perinatal or in utero transmission of EBV can induce an "infectious immunodeficiency." The clinical, histopathologic, and immunologic features resemble those described in adult homosexuals and drug addicts.

Acquired Immunodeficiency Syndrome↗