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Biomedical subjects

A Nelson

Publications and source records attributed to A Nelson.

At least 127 records · Page 7Linked to original sources
PubMed1988

Complementary oligodeoxynucleotide mediated inhibition of tobacco mosaic virus RNA translation in vitro.

Two different "antisense" oligodeoxynucleotides and their RNA analogues, each complementary to non-overlapping sequences of 51 bases near the 5' end of TMV RNA, inhibit in vitro translation of the genomic RNA in a rabbit reticulocyte lysate. Inhibition is dependent upon complementarity, concentration, and hybridization of the oligomers with TMV RNA. Inhibition is observed at molar ratios of TMV RNA to antisense oligomers as low as 1:1.5. A plateau of inhibition at which 10-25% of the control signal remains is achieved by molar ratios of TMV RNA:antisense DNA or RNA greater than or equal to 1:15. The extent of inhibition is not increased by the simultaneous presence of both complementary fragments. Oligodeoxynucleotides and their RNA analogues identical to the same regions of TMV RNA have no direct effect on translation, however, they can block inhibition by the antisense fragments. Translation of BMV RNA is not affected by any of the oligodeoxynucleotides. Polyacrylamide gel electrophoresis shows translation of TMV p126 is selectively inhibited. We conclude that the observed inhibition of translation is due to direct interference with ribosome function.

Base Sequence↗
PubMed1988

A new model for providing prehospital medical care in large stadiums.

To determine proper priorities for the provision of health care in large stadiums, we studied the medical incident patterns occurring in a major college facility and combined this with previously reported information from four other large stadiums. Medical incidents were an uncommon occurrence (1.20 to 5.23 per 10,000 people) with true medical emergencies being even more unusual (0.09 to 0.31 per 10,000 people). Cardiac arrest was rare (0.01 to 0.04 events per 10,000 people). However, the rates of successful resuscitation in three studies were 85% or higher. The previous studies were descriptive in nature and failed to provide specific recommendations for medical aid system configuration or response times. A model is proposed to provide rapid response of advanced life support care to victims of cardiac arrest. We believe that the use of this model in large stadiums throughout the United States could save as many as 100 lives during each football season.

Adolescent↗
PubMed1988

Appraisal of the event as a factor in coping with malpractice litigation.

The authors designed a study to explore medical malpractice litigation as a stressor, factors that contribute to doctors' appraisal of it, how they actually cope with it, and the potential effects on them and on their mode of practice. We interviewed 51 physicians who had been sued for medical malpractice. Those who identified litigation as their most stressful life event (Group 1, N = 11) experienced significantly more physical and emotional symptoms, especially those suggestive of a major depressive disorder, and used more emotion-focused coping mechanisms than those who identified some other event in life as being most stressful (Group 2, N = 39). The appraisal of litigation as one's most stressful life experience may be a useful predictor of coping response, with previous life experiences as a major contributing factor to this appraisal.

Adaptation, Psychological↗
PubMed1988

[3H]neurotensin(8-13) binds in human brain to the same sites as does [3H]neurotensin but with higher affinity.

The binding of [3H]neurotensin(8-13) to membranes from human frontal cortex at 0 degree C was time dependent, specific, saturable, and reversible. Saturation isotherms provided an equilibrium dissociation constant (KD) of 0.52 nM, and the maximal number of binding sites (Bmax) was 3.5 pmol/g original wet weight of tissue. Scatchard analysis yielded a straight line, and the Hill coefficient was equal to 1, a result indicating that [3H]neurotensin(8-13) bound to single, noncoopertive sites. The KD values of several analogs of neurotensin determined in competition with [3H]neurotensin(8-13) were similar to those previously determined in competition with [3H]neurotensin. The regional distribution of binding sites for [3H]neurotensin(8-13) was also similar to that for [3H]neurotensin. These results suggest that [3H]neurotensin(8-13) binds to the same sites as [3H]neurotensin and that [3H]neurotensin(8-13) has a higher affinity than [3H]neurotensin for these sites in human brain.

Aged↗
PubMed1988

T-lymphocyte subsets in the lesional skin of allogeneic and autologous bone marrow transplant patients.

Cutaneous biopsy specimens obtained from bone marrow transplant (BMT) patients, most with graft-vs-host disease (GVHD), were analyzed for infiltration by helper, cytotoxic, and suppressor T lymphocytes and natural killer cells. Lesional skin from patients with early mild GVHD and drug reactions showed a CD4/CD8 ratio of 5.0 or more, but later biopsy specimens from patients with acute GVHD and the majority of sections from those with chronic GVHD showed a CD4/CD8 ratio of 0.8 to 3.0 due to increased numbers of presumably cytotoxic cells. Significant numbers of suppressor (CD11 +/- CD16b-) cells were found in only one patient with severe chronic GVHD. Natural killer cells were not found. Preliminary examination of lesional skin from seven autologous BMT patients showed a similar trend of decreased CD4/CD8 ratios in the three patients with a syndrome that resembled GVHD. Analysis of CD4/CD8 ratios in serial biopsy specimens from patients with GVHD may allow more accurate monitoring of the progression of cutaneous GVHD and may help to elucidate the mechanism of development of the GVHD-like reaction in autologous BMT patients.

Biopsy↗
PubMed1987

Antagonism by neuroleptics of serotonin 5-HT1A and 5-HT2 receptors of normal human brain in vitro.

Using radioligand binding techniques and human frontal cortex, we determined the equilibrium dissociation constants (KDs) of 17 neuroleptics at the serotonin 5-HT1A and serotonin 5-HT2 receptors with [3H]WB4101 and [3H]ketanserin, respectively. At the serotonin 5-HT1A receptor, the most and least potent neuroleptics were chlorprothixene (KD = 230 nM) and fluphenazine (KD = 40 microM), respectively. At the serotonin 5-HT2 receptor, the most and least potent neuroleptics were spiperone (KD = 0.38 nM) and molindone, (KD = 5 microM), respectively.

Antipsychotic Agents↗
PubMed1986

Antagonism by antidepressants of serotonin S1 and S2 receptors of normal human brain in vitro.

Using radioligand binding techniques and human frontal cortex, we determined the equilibrium dissociation constants (KDs) of 25 antidepressants at the serotonin S1 (probably the S1A subtype) and serotonin S2 receptors using [3H]WB4101 and [3H]ketanserin, respectively. At the serotonin S1 receptor, the most and least potent antidepressants were trazodone (KD = 60 nM) and bupropion (KD = 170 microM), respectively. At the serotonin S2 receptor, the most and least potent antidepressants were amoxapine (KD = 0.6 nM) and bupropion (KD = 90 microM), respectively. Analysis of the data revealed a relationship between structure and serotonin S1 affinity for some tricyclic antidepressants. Buspirone, a new anxiolytic agent, possessed high affinity for the serotonin S1 receptor (KD = 3.8 nM).

Antidepressive Agents↗
PubMed1986

Bedside cognitive screening instruments. A critical assessment.

Bedside cognitive screening instruments are used increasingly in clinical and research settings to detect cognitive impairment and to quantify its severity. The authors review the five most frequently cited bedside screening tests that use an interview format and require brief administration times: the Mini-Mental State Examination, the Cognitive Capacity Screening Examination, Mattis Dementia Rating Scale, Kahn's Mental Status Questionnaire, and the Short Portable Mental Status Questionnaire. The tests all have adequate inter-rater reliability, and adequate test-retest reliability has been established for three of the tests. All of the tests show close correspondence with clinical diagnoses of delirium and dementia and are useful for the diagnosis and quantification of these syndromes. However, there is currently no evidence that the tests increase the level of diagnostic accuracy achieved through clinical examination alone. All of the tests have substantial false-negative rates, with false-negative errors frequent among patients with focal lesions, particularly of the right hemisphere. False-positive errors may be more common among patients with less education and lower socioeconomic status. The tests reviewed do not detect many types of cognitive deficit that may bear critically on differential diagnosis and case management. Suggestions are given for further research on the current measures and for the development of new screening tests that would meet a broader range of clinical purposes.

Adult↗
PubMed1986

Prenatal ultrasonic diagnosis of congenital duplication of the stomach.

A case of gastric duplication cyst first visualized sonographically in the prenatal period is described. The prenatal identification of abnormality allowed prompt postdelivery diagnosis and surgical treatment. The characteristic location of this cyst is in the right upper quadrant of the fetal abdomen. The presence of peristalitic activity within the cyst can point to a gastrointestinal origin. A hypoechoic outer rim and hyperechoic inner rim also suggests the stomach as the etiologic origin of the cyst. With this entity, the presence of associated congenital anomalies should be sought. No known associated genetic chromosomal anomalies are reported.

Adult↗
PubMed1985

Structure of taste buds in foliate papillae of the rhesus monkey, Macaca mulatta.

Taste buds in foliate papillae of the rhesus monkey were examined by electron microscopy. Three distinct cell types were identified. Type I cells were narrow elongated cells containing an oval nucleus, bundles of intermediate filaments, several Golgi bodies, and characteristic apical membrane-bounded dense granules. These cells exhibited morphological variations: some had a moderately dense cytoplasm, perinuclear free ribosomes, and flattened sacs of rough endoplasmic reticulum; others had a more lucent cytoplasm, dilated irregular rough endoplasmic reticulum, lysosome-like dense bodies, and lipid droplets. Type II cells typically contained a spherical, pale nucleus, a prominent nucleolus, supranuclear and infranuclear Golgi bodies, mitochondria with tubular cristae, and one or two centrioles. This cell type, too, showed some variation in the relative amounts of ribosomes and smooth endoplasmic reticulum, which varied inversely with each other. Type III cells were characterized by a clear apical cytoplasm essentially devoid of ribosomes and containing microtubules. In a few type III cells, the peri- and infranuclear regions contained many ribosomes and some rough endoplasmic reticulum. In most Type III cells, there were large numbers of dense and clear vesicles in the peri- and infranuclear regions; some of the vesicles were grouped in synapse-like arrangements with adjacent nerves. The morphological variations exhibited by all three cell types could be accounted for by age differences in each of the cells. This would be consistent with the notion that cell renewal occurs in each of the three cell populations.

Animals↗
PubMed1984

Antagonism by neuroleptics of neurotransmitter receptors of normal human brain in vitro.

Using radioligand binding techniques, we determined the equilibrium dissociation constants (KD's) for a series of neuroleptics at the dopamine (D-2), muscarinic, histamine H1, alpha 1- and alpha 2-adrenergic receptors of normal human brain tissue obtained at autopsy. Seventeen different compounds were studied at the D-2 receptor and 15 compounds at the remaining receptors. At the D-2 receptor of caudate nucleus, spiperone was the most potent compound (KD = 0.16 nM); clozapine the least potent (KD = 180 nM). The KD's for six compounds at the D-2 receptor of nucleus accumbens were not significantly different from their respective KD's in the caudate nucleus. The most potent and least potent compounds at the other receptors were clozapine and molindone at the muscarinic receptor, mesoridazine and molindone at the H1 receptor, spiperone and molindone at the alpha 1-receptor, and clozapine and haloperidol at the alpha 2-receptor, respectively.

Adolescent↗
PubMed1984

Subpleural pulmonary hamartoma: demonstration by computed tomography.

A case of a subpleural pulmonary hamartoma demonstrated by computed tomography is presented. The literature on subpleural pulmonary lesions demonstrated by computed tomography is reviewed. Although peripheral pulmonary hamartomas have been well documented, we believe this is the first demonstration of a subpleural location by computed tomography scanning. In the appropriate clinical setting, pulmonary hamartoma should be included in the differential diagnosis of subpleural lesions identified on computed tomography scanning of the chest.

Aged↗
PubMed1984

Antagonism by antidepressants of neurotransmitter receptors of normal human brain in vitro.

Using radioligand binding techniques, we determined the equilibrium dissociation constants (KDS) for a series of antidepressants at the histamine H1, muscarinic acetylcholine, alpha-1 and alpha-2 adrenergic and dopamine (D-2) receptors of normal human brain tissue obtained at autopsy. Twenty-five different antidepressants were studied at all but the D-2 receptor at which the number was 13 (including a metabolite of an antidepressant). Of all the receptor interactions studied, that at the histamine H1 receptor was in general the most potent interaction of this class of compounds, corresponding to results from studies using animal tissue as the source of receptors. At the human brain histamine H1 receptor, antidepressants remained among the most potent histamine H1 antagonists known, although their affinities for human receptors were lower than those for animal receptors. The most potent and the least potent compounds at the receptors were doxepin (KD = 0.24 nM) and fluvoxamine (KD = 109 microM) at the histamine H1 receptor, amitriptyline (KD = 18 nM) and trazodone (KD = 324 microM) at the muscarinic receptor, doxepin (KD = 24 nM) and viloxazine (KD = 14 microM) at the alpha-1 receptor, mianserin (KD = 73 nM) and bupropion (KD = 81 microM) at the alpha-2 receptor and amoxapine (KD = 160 nM) and trazodone (KD = 3800 nM) at the D-2 receptor, respectively. In general, compared to older drugs, the newer compounds tended to have lower affinities for these receptors.

Antidepressive Agents↗