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Biomedical subjects

G Clark

Publications and source records attributed to G Clark.

At least 163 records · Page 9Linked to original sources
PubMed1978

A comparison of methods for blocking staining of nucleic acids.

Using rat spinal cord as test material 4 methods for blocking staining of nucleic acids with simple basic dyes have been compared. Two of these methods--a perchloric acid procedure for tissue blocks and a Ba(OH)2 technic for sections--block staining of RNA. The other two-immersion of sections in solutions of dichlorodiammine Pt II or in 10% zirconyl chloride-blocked staining of both RNA and DNA. None of these methods hydrolyze DNA sufficiently to produce a positive Feulgen and no loss of protein could be demonstrated. With the three metal containing procedures some metal could be demonstrated in the sections. This deposition was primarily in nucleic acid containing structures and was greatest and most widespread with the zirconyl chloride. The latter method altered the color of all hematoxylin technics to a deep red. The separation of nuclear stains on the basis of their bonding characteristics into three groups (Lillie et al. 1976) was confirmed.

Animals↗
PubMed1978

Pancreatic cancer treated with carmustine, fluorouracil, and spironolactone: a randomized study.

A prospective randomized trial between two drug regimens in 38 patients with advanced pancreatic carcinoma was performed. The two-drug regimen consisted of carmustine and fluorouracil. The survival rate and response to these two drugs was compared to a three-drug regimen consisting of these same two drugs plus spironolactone. Objective partial responses were rare in both groups, being 3/18 in the two-drug group and 2/20 in the three-drug group. Life table analysis in previously untreated patients from time of treatment shows longer survival for the three-drug group, but this difference was not statistically significant.

Adult↗
PubMed1978

Radioimmunoassay for mono-(2-ethylhexyl) phthalate in unextracted plasma.

We report a radioimmunoassay for mono-(2-ethylhexyl) phthalate that has been coupled to a protein carrier as a radioligand. Competitive interference tests with a variety of related compounds indicated the assay to be highly specific. Quantitative comparison of mono-(2-ethylhexyl) phthalate values in plasma and serum samples between the radioimmunoassay and gas chromatographic procedures indicated a high reliability. Because this potentially toxic compound can leach into plasma from polyvinyl plastics, this assay should be particularly useful for those involved in the manufacture or use of medical devices made of them.

Animals↗
PubMed1977

The echocardiophone: a new means for observing spatial movement of the heart.

The paper describes a new pocket size instrument called the "Cardiophone" for the diagnosis of cardiac dysfunction. It is a continuous wave swept frequency ultrasonic echo-location system which produces dynamic auditory signals corresponding to the positional change of internal structures of the heart. The four valves are relatively easy to locate compared with conventional ECG machines. Preliminary clinical evaluation results are presented indicating the potential of the instrument for the general practitioner.

Echocardiography↗
PubMed1976

A consistent phosphotungstic acid hematoxylin stain for glial fibers.

After deceration, celloidinization and hydration, oxidize 10 micron paraffin sections for 15 min in a solution containing 0.3 g KMnO4 and 0.1 ml conc. H2SO4 per 100 ml distilled water. Wash in water and reduce in 5% oxalic acid until the sections are colorless. Wash thoroughly in water and place in 4% iron alum solution for two hours. Wash briefly in water and stain for two hours in phosphotungstic acid hematoxylin. Rinse briefly in 95% ethanol and dehydrate in n-butyl alcohol or absolute ethanol for 4 min with two changes, clear and mount. Glial fibers, myofibrils, red blood cells, etc. are stained blue while astrocyte cell bodies, collagen, etc. are stained red. This stain has proven highly consistent in a wide variety of astrocytic derangements. Despite the intensity of this PTAH modification, false positive staining was not observed.

Astrocytes↗
PubMed1975

Effects of additives on alum hematoxylin staining solutions.

All additives tested (ethyl alcohol, glycerine, chloral hydrate, ethylene and propylene glycol, and citric, malonic and maleic acids) in varying degrees limited the conversion of hematein to insoluble compounds. Peak absorbances increased slightly in hematoxylin solutions containing citric, malonic and maleic acids, but decreased with other additives, and in controls. After four months storage the absorbance in all solutions increased about 50%, acidity increased and staining effectiveness increased.

Alcohols↗
PubMed1975

Absorbances of hematoxylin solutions at varying pH levels.

An alum hematoxylin was prepared (0.5 g hematoxylin, 8 g potassium alum, distilled water 477.5 ml and Na10(3) solution, 1 mg/ml, 22.5 ml) and divided into 50 ml aliquots. The pH of these aliquots was adjusted with 2 1/2% NaOH or 10% H2SO4. As soon as the pH of a sample was adjusted the absorbance from 400 to 700 nm was recorded with a Cary 15 spectrophotometer using specially designed cuvettes and undiluted samples. The following day the absorbances at peak were measured on a Coleman Jr. spectrophotometer and three days later a variety of tissues was stained with each solution. The pH and peak of absorbance of the aliquots were pH = 2.0 450 NM, 2.5 505, 2.6 507, 2.7 515, 2.8 520, 2.9 530, 3.0 540, 3.1 550, 3.3 560, 3.5 560. In the stained material in the intensity of nuclear staining was about the same at all pH levels but non-specific staining was greatest in slides stained at pH = .5 and virtually absent in slides stained at pH = 2.0. At intermediate pH levels the amount of non-specific staining was intermediate.

Alum Compounds↗