[The study of occurrence mechanism in acute and chronic cerebral vasospasm]

Using radioimmunoassay, fluorescence and transmittal++ electronmicroscopy, we studied the of prostaglandin(PG), lipid peroxidation(LPO) and ultrastructure. Fresh arterial blood (imaging acute spasm) produced basilar arterial spasm strongly(+ + +) and vacuole deterioration in vascular walls but there were no changes in 6-keto-PGF1 alpha and TXB2 and PGE2 and LPO. Incubated arterial blood (imaging chronic spasm) produced basilar arterial spasm markedly (+ + +) also. Vacuole deterioration in vascular walls either, and decreased the level of 6-keto-PGF1 alpha apparently (P < 0.01) and elevated the content of LPO significantly (P < 0.01) and there were no changes in the level of TXB2 and PGE alpha. This experiment suggests that the mechanism of acute spasm and chronic spasm is different.

[Changes in lipid peroxides and superoxide dismutase as incubation of in vitro erythrocytes with cerebrospinal fluids and the action of various scavengers of free radicals]

In this experiment, LPO increased and SOD reduced as the time pass when erythrocytes (RBC) and CSF were mixed and incubated. There was a negative relationship between LPO and SOD. LPO in RBC of arterial blood was higher than that of venous blood after incubation for 3 days (P less than 0.01). When arterial RBCs were incubated together with various scavengers of free radical (SOD catalase and histidine and mannitol), the production of LPO was less than that of arterial RBC incubation singly (P less than 0.01). The change of LPO was not reduced when sodium nitrite and arterial RBC incubated. The results demonstrated that the scavengers of free radicals could be eliminated free radical but failed with sodium nitrite.

A graphical ICU workstation

A workstation designed to facilitate electronic charting in the intensive care unit is described. The system design incorporates a graphical, windows-based user interface. The system captures all data formerly recorded on the paper flowsheet including direct patient measurements, nursing assessment, patient care procedures, and nursing notes. It has the ability to represent charted data in a variety of graphical formats, thereby providing additional insights to facilitate the management of the critically ill patient. Initial nursing evaluation is described.

A knowledge-based experimental design system for nucleic acid engineering

Presented in this paper is a knowledge-based experimental design system that incorporates the domain expertise used in nucleic acid engineering, thus automating the processing of error-prone, laborious low-level work, and many decision-making steps, and guiding the biologist toward a workable plan. This allows the biologist to work at a higher abstraction level, concentrating on more fundamental, difficult and challenging problems directly related to protein structure - function relationships. Cassette-based site-directed mutagenesis and synthetic gene designs are used as examples to illustrate the utility of the knowledge-based system approach to experimental design.

A new method for the synthesis of a structural gene

A novel method of synthesizing a structural gene or gene fragment, consisting of the first synthesis of a single-stranded DNA (ssDNA), has been developed. As a preliminary test of this method, four synthetic genes or gene fragments have been synthesized. The first one with 396 base pairs (b.p.) codes for the mature rbcS from wheat, the next two with 370 and 342 b.p. respectively, for two half molecules of a gene for trichosanthin and the last one with 315 b.p. for the N-terminal 1-102 residues of human prourokinase. In all these syntheses, a plus-stranded DNA of the target gene was generally assembled by a stepwise or one step T4 DNA ligase reaction of six oligonucleotides (A, *pB, *pC, *pD, *pE and *pF) of 30-71 nucleotides long in the presence of two terminal complementary oligonucleotides (Ab' and eF') and three short inter-fragment complementary oligonucleotides (bc, cd and de). After purification, the synthetic ssDNA was inserted into a cloning vector, pWR13. The resulting product was directly used to transform a host cell. The structure of the cloned synthetic gene was confirmed by DNA sequence analysis.

Structural characterization of intact, branched oligosaccharides by high performance liquid chromatography and liquid secondary ion mass spectrometry

We report results of a mass-spectrometric-based strategy for determining the detailed structural features of N-linked oligosaccharides from glycoproteins. The method was used to characterize a series of intact, high mannose oligosaccharides isolated from human immunoglobulin M (IgM). The IgM was purified from a patient with Waldenstrom's macroglobulinemia. The strategy included releasing the oligosaccharides by digestion of the purified glycoprotein with endoglycosidase H, separating the released oligosaccharides by high resolution gel filtration, and derivatizing the resulting reducing termini with the uv-absorbing moiety, ethyl p-aminobenzoate. This particular derivative facilitates HPLC detection and provides centers for protonation and deprotonation enhancing liquid secondary ion mass spectra. Positive and negative ion spectra contained molecular species of similar abundance. However, fragment ion peaks yielding sequence information were significantly more prominent in the negative ion mass spectra. Furthermore, it was obvious that the fragmentation patterns differed substantially for linear and branched oligomers. For linear oligosaccharides, a smooth envelope of fragment ions was observed; from low to high mass there was an ordered decrease in ion abundance from both the reducing and nonreducing termini. This pattern of fragment ions was not observed for branched oligosaccharides since in these cases fragments at certain masses could not arise by single bond cleavages. Therefore, these fragments were either significantly reduced in abundance or absent as compared with identical fragments formed from linear molecules. Importantly, 200 pmol of an oligosaccharide could be derivatized, separated, and detected by mass spectrometry, allowing identification of previously unreported minor components of the IgM oligosaccharides. Therefore, this experimental strategy is particularly useful for the purification and detailed structural characterization of low abundance oligosaccharides isolated from heterogeneous biological samples.

A knowledge-based system for cassette mutagenesis experimental design

A knowledge-based system for the design and planning of cassette mutagenesis experiments has been developed for scientists working in the field of structural biology and protein engineering. The system applies domain-specific knowledge to manage the menial details and automate most of the decision-making steps involved in the design process. This allows scientists to work at a high abstraction level, and results in significant time savings and increased productivity. The system also includes an automated documentation facility to improve the efficiency and accuracy of record keeping.

Liquid and solid two-phase radioimmunoassay--simultaneous measurement of levels of triiodothyronine and thyroxine of human serum in a single specimen

The principle of the liquid and solid two-phase radioimmunoassay and its application to measuring the concentrations of triiodothyronine and thyroxine of human serum in a single sample at the same time are described in this paper. Rabbit anti-triiodothyronine antiserum was immobilized on the inner surface of a plastic tube as solid-phase radioimmunoassay system of testing triiodothyronine and donkey anti-rabbit gamma globulin antiserum was used to separate immunocomplex in liquid-phase radioimmunoassay system of thyroxine reaction. In both systems, radioiodine-125-labelled antigens were used as tracer. Through simple calculation, we can get the results of serum concentrations of triiodothyronine and thyroxine in a single sample. Compared with classical single-component radioimmunoassay of triiodothyronine and thyroxine and by methodological appraisal of two-phase radioimmunoassay itself, this method has the advantages of very high efficiency, reliability and also has the same specificity and precision.