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Biomedical subjects

R A Kramer

Publications and source records attributed to R A Kramer.

At least 91 records · Page 5Linked to original sources
PubMed1978

Enhancement of L-dopa incorporation into melanoma by dopa decarboxylase inhibition.

Melanoma cells possess a special biochemical pathway for the conversion of L-dopa to melanin. Selective incorparation of exogenous L-dopa into melanoma cells in vivo has been limited by extensive decarboxylation to dopamine. Pretreatment of animals bearing the S-91 Cloudman or ACI melanomas with Ro4-4602, a potent dopa decarboxylase inhibitor limited incorporation of label into adrenal tissue and enhanced entry of label into tumor. Six hours following pretreatment, the ratio of tumor to adrenal specific activities was altered from 0.25 to 1.5 for the S-91 melanoma and 0.68 to 1.99 for the ACI melanoma indicating diversion of metabolism away from catecholamine formation. The possibility of a selective diagnostic and/or therapeutic approach is proposed.

Adrenal Medulla↗
PubMed1978

Computed tomographic brain scanning in intraparenchymal pyogenic abscesses.

Retrospective analysis of 25 pyogenic brain abcesses diagnosed by computed tomography (CT) revealed relatively specific morphologic characteristics of these infections. The ability to obtain an early accurate diagnosis resulted in a dramatic decrease in patient morbidity and mortality. Repeated examinations by CT permitted close monitoring of the response of the abscess to antibiotic therapy. In some instances the need for surgical intervention was eliminated or the surgical approach was modified as a result of these studies.

Actinomycosis↗
PubMed1978

The angiographically occult cerebrovascular malformation. Report of three cases.

Three cases presenting with hemiparesis, headache, or seizures gave no history suggestive of subarachnoid or intracerebral hemorrhage. Carotid arteriograms were performed, and in each case failed to demonstrate a vascular malformation. In all three cases cerebral lesions were shown by either computerized tomographic (CT) scan, radionuclide scan, or both. Surgical exploration and biopsy revealed a vascular malformation in each case. The CT scans in two of the cases showed dense lesions that could suggest vascular malformation as a diagnostic possibility.

Adult↗
PubMed1978

Myocardial necrosis following general anesthesia in hemoglobin SC disease.

A 4-year-old girl with hemoglobin SC disease died following general anesthesia. Autopsy showed widespread intravascular sickling; staining with hematoxylin-basic fuchsin-picric acid demonstrated newly developed massive myocardial necrosis, a rarely documented finding. Anesthesia may produce conditions that provoke "crises" in patients with sickle hemoglobinopathies. Preoperative identification of sickle states and careful attention to hydration and oxygenation may minimize anesthetic risks in these patients.

Anemia, Sickle Cell↗
PubMed1977

Nucleotide sequence surrounding a ribonuclease III processing site in bacteriophage T7 RNA.

We have determined a nucleotide seuqence of 87 residues surrounding a ribonuclease III (endoribonuclease III; EC 3.1.4.24) processing site in the bacteriophage T7 intercistronic region between early genes 0.3 and 0.7. The structural requirements necessary for proper recognition and cleavage by RNase III are discussed. In addition, other structural features characteristic of this intercistronic boundary are described.

Base Sequence↗
PubMed1977

Computed tomography of angiographically occult cerebral vascular malformations.

Although some cerebral vascular malformations are angiographically occult, the correct diagnosis may be suggested by their appearance on computed tomography (CT). The authors advise caution in assuming that angiographically avascular lesions which show contrast enhancement on CT represent neoplasms rather than vascular malformations.

Adolescent↗
PubMed1977

Statistical profiles in computed tomography.

A diagnostic console consisting of a high resolution video display coupled to a microcomputer was programmed to enable us to derive a battery of statistical parameters from any area of interest on a CT scan. These statistical parameters enable us to characterize the CT numbers of areas of interest in a more meaningful way than has been possible with most currently available consoles. A combination of statistical parameters enables us to discriminate between certain lesions with similar appearance such as porencephalic cysts, epidermoid tumors and cystic gliomas.

Brain Diseases↗
PubMed1976

Isolation of bacteriophage lambda containing yeast ribosomal RNA genes: screening by in situ RNA hybridization to plaques.

We have developed an in situ hybridization technique which can be used to screen large numbers of hybrid bacteriophage for the presence of a particular inserted DNA sequence. Plaques of hybrid phage are formed on E. coli lawns on nitrocellulose filters, and their DNA is released, denatured, and fixed directly on the filters for hybridization to radioactive RNA probes. We have used this technique to isolate a number of hybrid bacteriophage lambda which contain EcoRl restriction fragments of the ribosomal RNA genes from yeast, and have examined the DNA from several of these phage.

Coliphages↗
PubMed1976

The isolation and characterization of bacteriophage T7 messenger RNA fragments containing an RNase III cleavage site.

We have isolated overlapping RNA fragments which contain the region surrounding the ribonuclease III cleavage site between bacteriophage T7 genes 0.3 and 0.7. Although all of these fragments contain the site of cleavage, only certain fragments are correctly recognized and cleaved by RNase III. Analysis of the cleavage products of the fragments indicates that the enzyme produces a single endonucleolytic break at this site in the T7 early RNA precursor molecule. In addition, the 3'-terminal adenylic acid residues observed previously on the in vivo T7 early RNA species were not found in these fragments and, therefore, must represent a post-transcriptional, post-processing modification of the RNA.

Base Sequence↗
PubMed1975

The terminal sequences of Bombyx mori 18S ribosomal RNA.

The 5' and 3' terminal T1 oligonucleotides of 32p-labelled B. mori 18S ribosomal RNA were isolated by a two dimensional electrophoretic (diagonal) technique. Nucleotide sequence analysis showed that the 3' terminal fragment, (G)AUCAUUAOH, is identical to that previously obtained from the 18S rRNA of several other eukaryotic species. The sequence of the B. mori 5' terminal fragment is pUCCUCG.

Animals↗
PubMed1975

An approach to contrast enhancement in computed tomography of the brain.

A total of 450 brain examinations were performed using computed tomography before and after intravenous infusion of methylglucamine diatrizoate 30%. In 110 cases involving a documented intracranial lesion, the scans were analyzed to determine the degree and usefulness of contrast enhancement. Enhancement was achieved in a wide variety of neoplastic and non-neoplastic lesions and was found to be of considerable help in detection of abnormality as well as in defining tumor morphology.

Adenoma, Chromophobe↗