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Biomedical subjects

J Erickson

Publications and source records attributed to J Erickson.

At least 73 records · Page 4Linked to original sources
PubMed1986

Neurologic complications in diabetics after metrizamide lumbar myelography.

Recognized risk factors for metrizamide myelography are seizure disorder, seizure-threshold-lowering drugs, dehydration, and possibly age. After observing serious neurologic complications in diabetic patients after routine metrizamide myelography, a retrospective study was conducted to determine if diabetes should be considered another independent and important risk factor. Forty-one diabetic patients who had lumbar metrizamide myelograms were compared with a control group of 110 nondiabetic patients. A significantly higher incidence was found of severe vomiting (15% vs. 3%, p less than 0.01) and neurologic complications (20% vs. 2%, p less than 0.001) in the diabetic population. Neurologic complications included one case each of seizure, severe encephalopathy, auditory and visual hallucinations, and prolonged somnolence and four cases of confusion-anxiety. Four of the diabetic patients had major transient elevations of blood pressure. These findings suggest that diabetics are a high-risk population for metrizamide myelography. The dose of metrizamide should be minimized, whenever possible. The new nonionic myelographic agents may prove to be safer in this population, but caution and careful follow-up should be exercised in the initial trials with these patients.

Aged↗
PubMed1986

Cancer induction in mice by feeding of the uncooked cultivated mushroom of commerce Agaricus bisporus.

The cultivated mushroom of commerce in the Western hemisphere, Agaricus bisporus, was given p.o. to randomly bred Swiss mice for 3 days and was followed by semisynthetic diet for 4 days each week for life. The mice were 6 weeks old at the beginning of the experiment. As a result of treatment, tumors were induced in the bone, forestomach, liver, and lungs in the following incidences: 16, 38, 8, and 40% in females and 16, 28, 12, and 62% in males, respectively. The corresponding tumor incidences in the untreated controls were 0, 0, 0, and 26% in females and 0, 4, 2, and 34% in males, respectively. Histopathologically, the tumors were classified as osteomas and osteosarcomas, squamous cell papillomas and carcinomas of forestomach, benign hepatomas, and adenomas and adenocarcinomas of lungs. The investigation thus proves the carcinogenicity of uncooked Agaricus bisporus.

Agaricales↗
PubMed1985

Sequence organization of repetitive elements in the flanking regions of the chloroplast ribosomal unit of Chlamydomonas reinhardii.

The flanking regions and the end of the chloroplast ribosomal unit of Chlamydomonas reinhardii have been sequenced. The upstream region of the ribosomal unit contains three open reading frames coding for 111, 117 and 124 amino acids, respectively. The latter polypeptide is partially related to the ribosomal protein L16 of E. coli. Two of the open reading frames overlap each other and are oriented in opposite direction. The region between these open reading frames and the 5' end of the 16S rRNA gene contains numerous short direct and inverted repeats which can be folded into large stem-loop structures. Sequence elements that resemble prokaryotic promoters are found in the same region. Several of the repeated elements are distributed throughout the non-coding regions of the chloroplast inverted repeat. Sequence comparison between the 5S rRNA and its gene does not reveal any significant sequence heterogeneity between the chloroplast 5S rRNA genes.

Base Sequence↗
PubMed1985

Morphological changes in the coronary circulation following experimental myocardial ischemia in swine.

The diagonal branches of the left anterior descending coronary artery in ten pigs were ligated for 5, 15, 30, 60 and 120 minutes. Pieces of occluded vessels were fixed with 2.5% buffered glutaraldehyde and processed for scanning and transmission electron microscopy. After 5 to 30 minutes of occlusion, endoplasmic reticulum and mitochondria begin to swell, vacuoles appear, and the number of pinocytic vesicles in endothelial cells decrease. After 60 minutes, endothelial cells contained numerous vacuoles, endoplasmic reticulum and mitochondria were markedly swollen, leukocytes and fragments detached from smooth muscle cells had infiltrated the subendothelial space, and endothelial cells were partially disrupted. Following 120 minutes of occlusion, internal elastic lamina had split, leukocytes had migrated into tunica media and smooth muscle cells had obviously penetrated into the subendothelial space, but no endothelial denudation or associated platelet accumulation was seen. These observations indicate that leukocyte infiltration and intrusion of partially disrupted endothelial cells precede, and may promote proliferation of medial smooth muscle cells into the tunica intima during myocardial ischemia. The events are reported for large conduit arterial branches of a main coronary artery.

Animals↗
PubMed1984

Remodeling of sperm chromatin following fertilization: nucleosome repeat length and histone variant transitions in the absence of DNA synthesis.

Within the first cell cycle following fertilization the average nucleosomal repeat length of sea urchin male pronuclear chromatin declines by 30-40 base pairs to a value typical of that found in the embryo. This decline occurs after a lag of about 30 min postfertilization, and is accompanied by replication of the male chromatin and accumulation of cleavage-stage (CS) core histone variants. When replication is inhibited by greater than 95% with aphidicolin, the decline in repeat length still occurs, although it is slightly retarded. The decline in repeat length also occurs when protein synthesis is blocked by greater than 98% and DNA synthesis by 60-70% with emetine. The adjustment of nucleosome repeat length therefore can occur in vivo without extensive movement of replication forks across the length of the chromatin, or normal progression of the cell cycle, and appears to require no proteins synthesized postfertilization. Blocking of DNA synthesis or protein synthesis also does not prevent the normal histone variant transitions involved in male pronuclear chromatin remodeling. Although their accumulation is slowed, CS core variants eventually become the predominant male pronuclear histones in their classes when replication is inhibited. Since a shortening of the average nucleosomal repeat length of approximately 10-20% is not sufficient to account for this large acquisition of CS variants, some of the sperm (Sp) core histones are probably displaced from the replication-blocked pronucleus. Therefore, accumulation of CS H2A and CS H2B are temporally correlated with the repeat length transition, whereas replication, normal progression of the cell cycle, and the early histone transitions involving SpH1 and SpH2B are not.

Animals↗
PubMed1983

Molecular analysis of rearrangements in human ribosomal RNA gene clones.

Human placental DNA, enriched for ribosomal sequences, was cloned in the phage vector lambda Charon 16A. Recombinants containing 28S rDNA sequences were isolated, and all were found to have deletions in the insert and/or vector DNA. Electron microscopic analysis was used to map the deletions and provide evidence that unstable forms of the recombinants can revert to the original vector or undergo further rearrangements. Specific deletions are manifested as previously unreported plaque phenotypes.

Bacteriophage lambda↗
PubMed1983

Radiographic techniques to evaluate paintings.

Radiographic techniques may be helpful in evaluation of the condition of paintings for their restoration, preservation, and occasionally to determine their authenticity. On the basis of experience with several of these procedures, the utility of each method is described in reference to specific "diagnoses" regarding paintings. Radiographic techniques have several advantages over other methods; they are nondestructive, they may be used to survey the entire painting, and they are subject to quantitative and serial analysis.

Art↗
PubMed1982

Structure and variation of human ribosomal DNA: the external transcribed spacer and adjacent regions.

A group of human ribosomal DNA (rDNA) recombinants that include the probable site for initiation of transcription have been examined for sequence polymorphism. A detailed restriction map of one rDNA insert was constructed using plasmid subclones and end-labeled segments. Comparison of 16 similar rDNA inserts by restriction and heteroduplex analysis demonstrated striking conservation of the external transcribed spacer and 18S gene regions, but defined a region where restriction sites for the enzymes Sma I, Hpa II, and Hha I become frequent or variable. This region extends for about 400--800 base pairs (bp) at the left end of the rDNA insert and is postulated to contain nontranscribed spacer sequences. The use of cloned rDNA segments as probes for the restriction analysis of genomic rDNA has demonstrated certain fixed sites in the nontranscribed spacer that do not vary significantly among different individuals or tumor cell lines. In contrast, restriction with the enzyme Sal I reveals several variable fragments, one of which has been found only in a retinoblastoma cell line.

Base Composition↗
PubMed1981

A comparison of carbon-fiber and aluminum front plates in rapid film changers.

The radiation transmission characteristics of 2-mm-thick aluminum front plates and 2-mm-thick carbon-fiber-reinforced plastic front plates for rapid film changers were compared. While the carbon-fiber plates were found to be intrinsically more radiolucent than the aluminum plates, the decrease in patient exposure with the carbon-fiber plates was only approximately 25%. No measurable differences in image quality were observed in carefully controlled experiments on the two types of front plates.

Aluminum↗
PubMed1979

False morel mushroom Gyromitra esculenta toxin: N-methyl-N-formylhdrazine carcinogenesis in mice.

N-Methyl-N-formylhydrazine was administered in drinking water as a 0.0039% solution to randomly bred Swiss albino mice for life starting from 6 weeks of age. The compound induced tumors of lungs, livers, blood vessels, gall bladder and bile ducts. The tumor incidences in these five tissues were 77, 46, 21, 10 and 7% while in the untreated controls they were 18, 1, 6, 0 and 0% respectively. Histopathologically, the tumors were classified as adenomas and adenocarcinomas of lungs, benign hepatomas and liver cell carcinomas, angiomas and angiosarcomas of blood vessels, adenomas and adenocarcinomas of gall bladder and cholangiomas. The macroscopic and light microscopic involvement of the tissues with the tumors are described and some of them are illustrated. N-Methyl-N-formylhydrazine is an ingredient of the edible mushroom, the false morel Gyromitra esculenta. The findings are discussed from the viewpoint of a potential human health hazard.

Animals↗
PubMed1979

Unlinked control of multiple glucocorticoid-induced processes in HTC cells.

HTC cell variants chosen for their lack of tyrosine aminotransferase (EC 2.6.1.5) (TAT) induction by glucocorticoids were tested for interrelated effects on other glucocorticoid responses: TAT induction by dibutyryl cyclic AMP (dBcAMP) +/- dexamethasone, glutamine synthetase (GS) induction, cyclic nucleotide phosphodieterase (PDE) suppression, inhibition of alpha-aminoisobutyric acid (AIB) uptake, inhibition of plasminogen activator (PA), and induction of mouse mammary tumor virus (MTV). Loss of TAT induction by steroid was accompanied by loss of TAT induction by dBcAMP and of PDE suppression by steroid. In addition, subclones of MTV-infected cells were examined for the effect of the virus on glutamine synthetase (GS) and TAT induction. The virus had no effect on their induction in wild-type cells and no effect on GS induction in the variants. One MTV-infected subclone from a TAT variant, however, showed significant return of TAT induction.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1978

Lung tumorigenesis by 1,2-diformylhydrazine in mice.

1,2-Diformylhydrazine was administered in drinking water as a 2% solution to randomly bred Swiss albino mice for life from 6 weeks of age. As a result of treatment, the lung tumor incidence rose from 15 to 96% in females and from 22 to 82% in males. The treatment had no statistically significant effect on the development of other types of tumors. Histopathologically, the neoplasms exhibited the characteristic appearance of adenomas and adenocarcinomas of the lungs. The work is part of a series of studies aimed at revealing the relative carcinogenic potency of mono- and dialkyl-hydrazines and also their possible environmental significance as cancer causative agents.

Adenocarcinoma↗
PubMed1978

Tumor induction with the N'-acetyl derivative of 4-hydroxymethyl-phenylhydrazine, a metabolite of agaritine of Agaricus bisporus.

N'-Acetyl-4-(hydroxymethyl)phenylhydrazine was administered as a 0.0625% solution in drinking water continuously for the life span of Swiss mice, from 6 weeks of age. Compared to that in untreated controls, in treated animals the lung tumor incidence rose from 15 to 34% in females and 22 to 48% in males, whereas the incidence of blood vessel tumors increased from 8 to 32% in females and from 5 to 30% in males. Histopathologically, the tumors were classified as adenomas and adenocarcinomas of the lungs and angiomas and angiosarcomas of the blood vessels. The commonly eaten mushroom Agaricus bisporus contains beta-N-[gamma-L(+)-glutamyl]-4-hydroxymethylphenylhydrazine, which under certain conditions yields 4-hydroxymethylphenylhydrazine and L-glutamic acid. Since 4-hydroxymethylphenylhydrazine is relatively unstable, its acetyl derivative was synthesized for this study. The possible environmental significance of the findings is discussed.

Adenocarcinoma↗
PubMed1977

Reversal of the toxicity of hydrazine an analogues by pyridoxine hydrochloride.

Single subcutaneous injections of each of five substituted hydrazines were given alone and jointly with pyridoxine hydrochloride (PH) to Swiss mice. The convulsive, toxic, and lethal effects of four compounds--methylhydrazine (MH), ethylhydrazine hydrochloride (EH), n-butylhydrazine hydrochloride (BH), and beta-N-[gamma-L(+)-glutamyl]-4-hydroxymethylphenylhydrazine--were successfully prevented by administering PH before and/or after injection. The toxic symptoms caused by N-methyl-N-formylhydrazine (MFH) were, however, only slightly inhibited by this vitamin.

Animals↗
PubMed1976

Trimethylhydrazine hydrochloride as a tumor inducer in Swiss mice.

A 0.05% solution of trimethylhydrazine hydrochloride (TMH) administered for a lifetime in drinking water to outbred Swiss albino mice, beginning at 6 weeks of age, induced tumors of blood vessels, lungs, and kidneys. The tumor incidences in these tissues in untreated controls were 5,22 and 0%, whereas in the treated groups the corresponding tumor incidences increased to 85, 44, and 6%, respectively. Histopathologically, tumors were classified as angiosarcomas of blood vessels and adenomas of the lungs and kidneys. The study thus demonstrated the tumorigenicity of TMH. Contrary to expectation, the chemical structure modification apparently failed to alter qualitatively the tumorigenic response.

Adenoma↗