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Biomedical subjects

D Greiff

Publications and source records attributed to D Greiff.

At least 19 recordsLinked to original sources
PubMed1992

Development of cycles for lyophilization.

In order to find the freeze-drying cycle for the effective drying of a given biological entity or a material of biologic origin by sublimation of ice in vacuo, numerous time-consuming, trial and error preliminary studies have been required. Following a series of studies using different shelf temperatures, -30 degrees, -10 degrees, 0 degrees, +10 degrees and +20 degrees C, and elapsed times of 1,500, 2,000, 2,700, 4,000 and 5,500 minutes, plug characteristics and contents of residual moistures of freeze-dried 3 ml samples of 2% serum albumin were determined. Using the statistical method of least squares, geometric curves were fitted to the plot of times versus residual moistures for the several shelf temperatures. The equations for the fitted curves were used to construct a table showing the contents of residual moistures at 300 minute intervals. This table was used for developing successful drying cycles for several concentrations of serum albumin, dilute solutions of interferon, and serum containing HLA antibodies.

Antibodies↗
PubMed1983

Effect of motilin on the opossum upper gastrointestinal tract and sphincter of Oddi.

We studied the effect of motilin on myoelectric activity of the sphincter of Oddi (SO) and upper gastrointestinal tract in conscious opposums. In 17 animals, bipolar electrodes were implanted on the gastric antrum, SO, duodenum, and jejunum. Subsequent 8-h recordings reconfirmed our previous findings that SO spike burst rate changed with interdigestive cycles of the gastrointestinal migrating myoelectric complex (MMC), becoming maximal during passage of phase III activity through the duodenum. In eight animals, peak motilin levels were shown to occur concurrently with maximal SO spike burst rate and MMC phase III activity in the duodenum. Motilin infusion (0.3 and 0.9 micrograms X kg-1 X h-1), given for 30-60 min starting 10 min after duodenal phase III, elicited premature MMC activity that originated in the stomach. Maximal SO activity occurred coincident with passage of premature phase III activity through the duodenum. Pulse intravenous doses of motilin (25-1,600 ng/kg) generally caused an immediate increase in spike burst activity in the gastric antrum, duodenum, and SO that lasted 3-5 min and was often followed by a premature MMC, usually starting in the antrum and progressing through the duodenum and jejunum. Increases in SO spike burst rate also occurred concurrent with motilin-induced, premature duodenal phase III. Motilin given at 5-60% of the duodenal MMC cycle length elicited premature MMCs at 10-60% of the cycle, but no premature MMCs were elicited by any of the motilin doses at the 5% intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Ampulla of Vater↗
PubMed1976

An improved freeze-dried bilirubin preparation.

We describe the conditions for successful freeze-drying of bilirubin solutions in the presence of dimethylsulfoxide and human serum albumin. Freeze-dried bilirubin preparations rehydrate readily, rapidly resulting in clear solutions. The preparations exhibit excellent homogeneity and stability at -20 degrees C. Accelerated storage tests indicate that the freeze-dried product would also be stable at higher temperatures but our results do not permit, at the present time, to make accurate predictions regarding the stability at 4 degrees C or 0 degrees C. We believe that our approach will permit manufacturers of bilirubin calibrators for clinical use to improve the quality of their products.

Animals↗
PubMed1970

Stabilities of suspensions of influenza virus dried by sublimation of ice in vacuo to different contents of residual moisture and sealed under different gases.

Suspensions of influenza virus were dried by sublimation of ice in vacuo to contents of residual moisture of 2.8, 1.6, or 0.6%. After drying, the preparations were sealed under helium, argon, nitrogen, or a mixture of oxygen and nitrogen (30% O(2), 70% N(2)). Stabilities of the several preparations were determined by an accelerated storage test. Based on the times predicted for the dried preparations stored at preselected temperatures to lose 1 log of infectivity titer, the order of stabilities in relation to residual moisture, gas was as follows: 1.6%, He > 0.6%, He > 2.8%, He > 1.6%, Ar > 2.8%, N(2) > 2.8%, Ar > 1.6%, N(2) > 2.8%, O(2) > 0.6%, Ar > 0.6%, N(2) > 1.6%, O(2) > 0.6%, O(2). The stability of the preparation sealed under helium and dried to the content of residual moisture found best for this gas (1.6%) resulted in an increased stability of the order of years as compared to the other preparations tested.

Argon↗
PubMed1970

Toxicity of pneumococcal neuraminidase.

Sterile sonic-treated materials of pneumococci grown in media containing N-acetylmannosamine as the carbohydrate source were lethal for mice. Purification of the toxic factor led to its identification as the enzyme neuraminidase.

Journal Article↗
PubMed1969

Stabilities of dried suspensions of influenza virus sealed in a vacuum or under different gases.

Suspensions of purified influenza virus, dried to a 1.4% content of residual moisture by sublimation of ice in vacuo, were sealed in a vacuum or under different gases of high purity. The stabilities of the several preparations were determined by an accelerated storage test. Based on the times predicted for the dried preparations stored at different temperatures to lose 1 log of infectivity titer, the order of stabilities in relation to sealing in vacuum or under different gases was as follows: helium > hydrogen > vacuum > argon > nitrogen > oxygen > carbon dioxide.

Argon↗
PubMed1968

Stability of suspensions of influenza virus dried to different contents of residual moisture by sublimation in vacuo.

After freezing, suspensions of influenza virus were dried by sublimation of water in vacuo to contents of residual moisture of 3.2, 2.1, 1.7, 1, or 0.4%. The stability of the several suspensions was determined by an accelerated storage test. Based on the times predicted for the dried preparations stored at different temperatures to lose 1 log of infectivity titer, the order of stability in relation to residual moistures was as follows: 1.7% > 2.1% > 1% > 3.2% > 0.4%.

Humidity↗