Biomedical subjects

S Vemuri

Publications and source records attributed to S Vemuri.

4 recordsLinked to original sources

PubMed1992

A correlation between digoxin plasma concentrations and systolic time intervals in hospitalized congestive heart failure patients.

Plasma digoxin level is at best an indirect measure of pharmacological response to digoxin in patients being treated for congestive heart failure. Systolic time interval (STI) measurement reflecting left ventricular function at the physiological site of action of digoxin, is both more direct and non-invasive. With a portable instrument to measure systolic time intervals, the measurement can also be convenient for hospital staff. A portable electrocardiogram (ECG) machine was modified to mimic the capabilities of a large, multichannel model. Upon satisfactory evaluation, it was employed in the collection of systolic time interval data from five hospitalized patients undergoing digoxin treatment. An attempt was made to show a relationship between STI indices and digoxin plasma concentrations. Additionally, a statistical comparison was made of change in STI (delta STI) and plasma digoxin concentration both before and after drug administrations. The change in pre-ejection period (delta PEP) values show a significant difference over the changes in total electromechanical systole (delta QS2) and the changes in left ventricular ejection time (delta LVET). In three congestive heart failure patients, the time course of the change in plasma concentration showed good correspondence with delta PEP.

Adolescent↗

PubMed1992

Lyophilization cycle development for interleukin-2.

The effects of temperature and pressure variation on the lyophilization of interleukin-2 (IL-2) were studied. The human recombinant IL-2 used in this study was synthesized in and purified from E. coli, formulated, and then submitted to experimental lyophilization procedures. The collapse temperature of the formulation was first determined to be -25 degrees C by differential scanning calorimetry. The effects of chamber pressure and shelf temperature on IL-2 during lyophilization were evaluated. Lyophilization chamber pressures were varied from 100 mu to 300 mu in combination with the different chamber pressures. Lyophilized cake quality was assessed by evaluating three of its properties: residual moisture, by the Karl Fischer method; the monomeric content of the protein, by RP-HPLC; and oligomeric content, by SDS-PAGE. Process uniformity was checked by determining residual moisture in cakes collected from various locations in the chamber. The experimental data show that IL-2 can be lyophilized in a pilot unit within 30 hours. The IL-2 lyophilized at various primary drying conditions retained its purity and potency throughout the stability study period (12 months).

Calorimetry, Differential Scanning↗

PubMed1991

The experience of pain and perceptions of quality of life: validation of a conceptual model.

Pain is a common symptom of terminally ill cancer patients and a major challenge for hospice care. This paper presents a conceptual model of the relationship between pain and quality of life that was derived from the authors' previous research. The model should prove useful to hospice clinicians and researchers in evaluating the impact of palliative care on the quality of life.

Evaluation Studies as Topic↗

PubMed1990

MacProMass: a computer program to correlate mass spectral data to peptide and protein structures.

A program known as MacProMass has been written for Macintosh computers to assist in the analysis of mass spectral data of peptides and proteins. The program employs a user friendly, graphical interface and accommodates a variety of protein structures including cyclic peptides and multiple chain proteins. In addition to molecular mass calculations for positive and negative molecular ions, MacProMass also calculates elemental composition, amino acid composition, isoelectric point, surface free energy, and high-performance liquid chromatography index values for whole structures and peptide fragments resulting from enzymatic or chemical degradation. Users can program their own amino acid residues and terminal groups. In addition to search routines for both mass and sequence, theoretical fragment ions for peptide mass spectra can be calculated. Analysis of variant proteins is facilitated with a subroutine that systematically catalogs single amino acid substitutions that correspond to mass differences between observed and expected molecular ions. Interchain and intrachain disulfide bonds and other types of linkages are maintained throughout the chemical and enzymatic degradation operations.

Amino Acid Sequence↗