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Biomedical subjects

K Lee

Publications and source records attributed to K Lee.

At least 883 records · Page 49Linked to original sources
PubMed1982

Viruses of symbiotic Chlorella-like algae isolated from Paramecium bursaria and Hydra viridis.

We previously reported that isolation of symbiotic Chlorella-like algae from the Florida strain of Hydra viridis induced replication of a virus (designated HVCV-1) in the algae. We now report that isolation of symbiotic Chlorella-like algae from four other sources of green hydra and one source of the protozoan Paramecium bursaria also induced virus synthesis. Algae from one of these hydra contained a virus identical to HVCV-1 (based on its rate of sedimentation, buoyant density, reaction to HVCV-1 antiserum, and DNA restriction fragments) whereas algae from the other three hydra contained another similar, but distinct, virus (designated HVCV-2). The virus from the paramecium algae (designated PBCV-1) was distinct from both HVCV-1 and HVCV-2. The symbiotic algae in the hydra could also be distinguished ultrastructurally. Chloroplasts of both algae that produced HVCV-1 lacked a pyrenoid whereas chloroplasts of the other three symbiotic algae contained pyrenoids. Since all symbiotic eukaryotic algae we have examined have had virus, a potential viral role in symbiosis is suggested.

Journal Article↗
PubMed1982

A combined in vivo/in vitro study of the presynaptic release of adenosine derivatives in the hippocampus.

To investigate the release of adenine compounds from defined neuronal pathways, we employed a hippocampal slice preparation in which a selective-loading of the releasable pools was achieved in vivo with the aid of axonal transport. By injecting radioactive adenosine stereotaxically into the entorhinal cortex, the major afferent system to the dentate gyrus (the perforant path) was loaded within 20-36 h, at which time the rats were killed and hippocampal slices were prepared. The efflux of radioactive material, as recovered from the perfusate and measured in a scintillation counter, was found to be significantly increased in response to electrophysiologically controlled stimulation of the perforant path but not to stimulation of an alternative fiber tract, the fimbria. These findings provide supportive and more direct evidence for an activation-coupled release of adenosine derivatives from presynaptic sites in the central nervous system.

Adenosine↗
PubMed1982

Incremental value of the exercise test for diagnosing the presence or absence of coronary artery disease.

To determine the incremental value of the exercise test (ETT) for diagnosing coronary artery disease (CAD), we derived a multivariate logistic regression model for the pre-ETT prediction of CAD using data from 3840 patients at Duke University. We then applied the model to 324 patients at the Brigham and Women's Hospital. Using seven clinical factors, the multivariate model had an 84% overall predictive accuracy on both the training (Duke) and the validation (Brigham) sets of patients. Three ETT factors (ST-segment change in patients not taking digitalis, absence of ST-segment change in patients taking digitalis, ETT stopped because of ECG or blood pressure changes) had incremental, significant predictive power, but overall predictive accuracy based on both clinical and ETT factors improved only to 87%. When the ETT result was important enough to move the probability of CAD across a potential therapeutic threshold, the direction of the change in probability was correct only two-thirds of the time. Thus, the ETT was of limited value in predicting the presence or absence of CAD after other easily obtainable clinical data were taken into account.

Adult↗
PubMed1981

The binding site for ribosomal protein L11 within 23 S ribosomal RNA of Escherichia coli.

Ribosomal protein L11 of Escherichia coli was bound to 23 S rRNA and the resultant complex was digested with ribonuclease T1. A single RNA fragment, protected by protein L11, was isolated from such digests and was shown to rebind specifically to protein L11. The nucleotide sequence of this RNA fragment was examined by two-dimensional fingerprinting of ribonuclease digests. It proved to be 61 residues long and the constituent oligonucleotides could be fitted perfectly between residues 1052 and 1112 of the nucleotide sequence of E. coli 23 S rRNA.

Bacterial Proteins↗
PubMed1981

Fine-needle aspiration cytology in the management of gynecologic cancer.

The technique and application of fine-needle aspiration cytology in the management of gynecologic cancer are discussed. The authors report 90 cases that have been evaluated by means of fine-needle technique. The technique has been applied both for primary diagnosis and for follow-up evaluation. Among the 90 cases reported, there was two false negatives and one false positive and three cases in which the histologic findings were false negative.

Adenocarcinoma↗
PubMed1981

Sodium valproate versus phenobarbital in the prophylactic treatment of febrile convulsions in childhood.

Phenobarbital has been shown to offer effective prophylaxis against childhood febrile convulsions. However, a high percentage of children do not tolerate phenobarbital, mainly due to behavioral changes. Valproate, due to its low toxicity, appears to be an attractive alternative to phenobarbital treatment. Ninety children admitted with their first febrile convulsion were offered prophylactic treatment with either phenobarbital 3-5 mg/kg/day or valproate 20-30 mt/kg/day. Twenty-five children whose parents refused prophylactic treatment make up an untreated control group. Serum levels of the appropriate drug were measured at each follow-up visit. The three groups appear to be comparable. Twenty-one per cent of the phenobarbital treated children required discontinuation of the drug due to side effects. All the children tolerated valproate therapy. Twelve out of 25 untreated children suffered recurrences. Eight out of 33 children treated with phenobarbital suffered recurrences. Four out of 32 children on valproate therapy had recurrences. The difference between valproate treatment and no therapy at all is highly significant (p less than 0.001). Phenobarbital did not reduce the risk of recurrence. We now recommend prophylactic treatment with valproate to children with febrile seizures.

Child Behavior Disorders↗
PubMed1981

Continuous transepidermal drug collection: basis for use in assessing drug intake and pharmacokinetics.

Continuous transepidermal drug collection (CTDC) has been proposed for use in assessing ethanol intake and in monitoring compliance with therapeutic regimens. Exploration of a theoretical basis for use of CTDC in these circumstances and for its use in assessing other aspects of drug disposition kinetics was undertaken. Effects of single and multicompartmental drug disposition models, single dose and multiple dose regimens, with regular and irregular doses and dosing intervals, and zero-order, first-order, and Michaelis-Menten excretion patterns were explored. First-order transepidermal drug transfer was assumed with and without back transfer from the collection device. These analyses suggest that the utility of CTDC is severely restricted when back transfer from the collection device is substantial. With back transfer minimized, CTDC may be a useful tool for assessing amount of drug exposure, compliance with therapeutic regimens, and relative bioavailability, but offers little advantage over discrete sampling of other body fluids in the study of other aspects of drug disposition kinetics.

Half-Life↗
PubMed1981

Effect of bronchoconstriction on the firing behavior of pulmonary stretch receptors.

To study the effect of bronchoconstriction on the activity of pulmonary stretch receptors (PSRs), acetylcholine aerosols (0.05% solution) were delivered continuously into the lungs while the afferent activity of a single PSR was recorded from a filament of the vagus nerve. The relationship between the PSR frequency (fPSR) and the transpulmonary pressure (Ptp) was examined during both constant volume ventilation and hyperinflation. During bronchoconstriction, the peak fPSR for the same tidal volume increased significantly (P less than 0.05) compared to the control response obtained with saline aerosols. However, the fPSR at functional residual capacity decreased in the receptors above the carina but increased in those below. Bronchoconstriction induced a hysteresis in the dynamic Ptp-fPSR relationship during hyperinflation in 11 out of the 21 receptors studied: a clockwise hysteresis was found in those receptors above the carina whereas a counterclockwise one in those below. Results of these studies suggest that the response of PSRs to bronchoconstriction depends on their locations in the tracheobronchial tree.

Acetylcholine↗
PubMed1981

An evaluation of the effects of lithium in the treatment of chronic alcoholism. II. Assessment of the two-period crossover design.

Analysis of self-reported alcohol intake by alcoholic subjects participating in a two-period crossover trial of lithium versus placebo failed to demonstrate a significant effect of lithium in reducing alcohol consumption. An appraisal of the adequacy of this study design to meet the original objective of the trial was undertaken. It was impossible under this study design to simultaneously and unequivocally estimate effects of treatment periods, drug carryover, sequence group and other period by treatment interactions in addiction to the lithium/placebo effects. Presence of one or more of these additional influences on the trial outcome not only complicated the interpretation of results but diminished the power of the trial design to test the major hypothesis of interest, that lithium could reduce alcohol intake. We conclude that the two-period crossover design has serious drawbacks in this clinical trial setting and that alternative strategies need to be considered for future trials.

Adult↗
PubMed1981

Temporal lobe epilepsy -- not a consequence of childhood febrile convulsions in Denmark.

Temporal lobe epilepsy in particular has been considered a consequence of childhood febrile convulsions. Previous studies have dealt with populations of epileptic children. This retrospective, follow-up study concerns 362 children with a primary diagnosis of febrile convulsions. 4% developed epilepsy. When followed into early adulthood one half of those remitted. The incidence of temporal lobe epilepsy among the none-remitters did not differ from that of a random population of epileptics.

Adolescent↗
PubMed1981

Circulatory effects of acute or chronic endotoxemia in rats.

A study was made of the effects of acute (4 h) infusion of Escherichia coli endotoxin on cardiovascular function in rats. Rats with acute endotoxemia had a reduced cardiac output but maintained their arterial blood pressure. Fractional distribution of the cardiac output was increased to the liver and reduced to the gastorintestinal tract and skin. No changes in fractional distribution to the kidneys, lungs, or heart were observed although absolute blood flow to these areas was reduced. Rats with chronic endotoxemia had a reduced cardiac output and hypotension with no change in peripheral resistance. Other changes resembled those seen in acute endotoxemia apart from a low renal fraction of the cardiac output. Calculation and interpretation of blood flow changes in these animals was difficult because of a large fall in hematocrit and changes in organ weight.

Animals↗
PubMed1981

Determinants of neurobehavioral outcome in low-birth-weights infants.

The relative importance of (1) birth weight, gestational age, and head circumference at birth, and (2) appropriateness of birth weight and head circumference to gestational age in the predictability of neurobehavioral outcome was evaluated in 127 low-birth-weight infants at 7 months of age. Lower absolute birth weights, shorter gestational ages, and smaller head circumferences at birth correlated with poorer outcome (Bayley Scales of Infant Development and abnormal neurologic examination) at the corrected chronologic age of 7 months (r = .28 to .42, all P less than .005). The incidence of low scores on the Mental Development Index and of severe neurologic deficit was significantly higher in small head circumference for gestational age infants than in appropriate head circumference for gestational age infants (both, P less than .05). In the absence of small head circumference, small for gestational age infants had similar incidences of low Bayley scores and abnormal neurologic examinations as did appropriate for gestational age infants. These observations suggest that head circumference at birth may be the single most important variable for subsequent neurobehavioral outcome, and that both birth weight and gestational age may simply be markers of fetal head growth in their relationship to later outcome.

Birth Weight↗