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Biomedical subjects

D D Wood

Publications and source records attributed to D D Wood.

At least 19 recordsLinked to original sources
PubMed1992

The N terminus of human myelin basic protein consists of C2, C4, C6, and C8 alkyl carboxylic acids.

Peptide 1-21, generated by cyanogen bromide cleavage of each of two highly purified components of human myelin basic protein, components 1 and 8, gave a series of peaks in the fast atom bombardment mass spectra with m/z 2299, 2327, 2355, 2383, and 2411, indicating additions of 42, 70, 98, 126, and 154 atomic mass units respectively with m/z 2327 and 2355 as the dominant species. The pentafluorobenzyl esters prepared from an acid hydrolysate analyzed by negative ion chemical ionization gas chromatography mass spectrometry confirmed that C6, C8, and C10 fatty acids were present. These data demonstrated (i) that the N terminus of a myelin basic protein is not simply acetylated but contains C2, C4, C6, C8, and C10 fatty acids with C4 and C6 as the dominant species, (ii) the two components studied (C-1 and C-8) showed different relative amounts of C2 and C8 in particular, and (iii) human myelin basic protein is the first protein to be reported with a complex N terminus consisting of several alkyl carboxylic acid species.

Amino Acid Sequence↗
PubMed1992

An immunochemical comparison of human myelin basic protein and its modified, citrullinated form, C8.

An immunochemical analysis was conducted to compare the C1 isomer of human myelin basic protein (MBP) with the newly described and less cationic, citrullinated isomer of MBP referred to as C8. Ten polyclonal antisera directed at multiple epitopes or restricted regions of MBP were used in radioimmunoassays to examine MBP-C1 and MBP-C8. Antisera reactive with MBP peptide 1-14 clearly distinguished MBP-C1 from MBP-C8. Antisera to human MBP peptides 10-19 and 90-170, but not to MBP peptide 69-89, showed modest differences between MBP-C1 and MBP-C8. The MBP-C8s from multiple sclerosis (MS) and non-MS brain reacted essentially the same. With murine monoclonal antibodies and enzyme-linked immunosorbent assay (ELISA), differences between MBP-C8 and other isomers were shown for anti-MBP 10-19 but not for anti-MBP 1-9 or anti-MBP 80-89. These findings imply differences in sequence or conformation in the structure of MBP-C7 compared to MBP-C1, most notably near the amino terminus.

Adult↗
PubMed1979

Comparison of the plaque-stimulating and thymocyte-stimulating activities derived from human monocytes.

Human monocytes have been reported to release factors that can elicit distinct responses from a number of different target cells. In this report, it is shown that most of the thymocyte-stimulating activity in supernatants of endotoxin-stimulated monocytes can be separated from the plaque-stimulating factor (BAF) by gel filtration and isoelectric focusing; however, since these activities could not be entirely resolved, the question was addressed whether the plaque-stimulating activity of BAF depends upon the stimulation of T-cells. Several critical experiments are reported which fail to support this hypothesis. On the other hand, these experiments led to the observation that the response to BAF depends on both an IgM-positive B-cell and a G10-adherent, plastic nonadherent, IgM-negative, irradiation-insensitive cell found in nude splenocytes. Finally, the possibility is discussed that this factor may be responsible for many of the physiological sequelae of infection.

Animals↗
PubMed1979

Purification and properties of human B cell-activating factor.

Human monocytes, when appropriately stimulated in vitro, release into the culture medium a factor (BAF) that stimulates the IgM response of T-depleted murine splenocytes to heterologous erythrocytes. The behavior of this factor on gel filtration, isoelectric focusing, ion exchange chromatography, and isopycnic centrifugation was studied. BAF appears to be a molecule of 15,000 daltons, pI 6.5, 1.33 g/ml with low solubility at low ionic strength. It is stable to acid, mild heating, and long-term storage. Activity is lost in alkali or by boiling. Papain may reduce BAF activity slightly, whereas trypsin and chymotrypsin have no significant effect. These properties are similar to those of other monokines reported to have a similar m.w.

Animals↗
PubMed1978

A simple method for the preparation and storage of helper T cells.

Relatively purified populations of helper T cells free of active PFC precursors can be prepared from primed splenocytes by irradiation, hypotonic shock, and filtration over glass wool. These purified populations can be stored and helper activity recovered undiminished after up to 6 months of cryopreservation.

Animals↗
PubMed1978

Sensitization to myelin basic protein in attacks of multiple sclerosis. A preliminary report.

Recent attempts to detect the presence of antibody to encephalitogenic basic protein in multiple sclerosis have generally been unsuccessful. The utilization of a new system of double immunodiffusion in detecting such antibody in EAE serum prompted us to apply this method in the search of such antibody MS sera. In our preliminary investigation of 67 sera, antibody was detectable in MS sera, but it was most often found during convalescence rather than an acute exacerbation of illness. Antibody was also found in several myasthenic patients, and occasionally in subjects with other neurological disease.

Antibodies↗
PubMed1977

Localization of the basic protein and lipophilin in the myelin membrane with a non-penetrating reagent.

The localization of proteins in myelin was studied by the use of a non-penetrating reagent. Tritiated 4,4'-diisothiocyano-2,2'-ditritiostilbene disulfonic acid was used to label the isolated myelin membrane. The membrane was labelled, the basic protein and the hydrophobic protein, lipophilin, were isolated. After 10 min of exposure to the reagent, the specific activity of lipophilin was found to be 10 times greater than that of the basic protein. Water shock did not alter the specific activities. However, sonication increased the specific activity of lipophilin but not that of basic protein. When the isolated proteins were labelled with 3H-labelled 4,4'-diisothiocyano-2,2'-ditritiostilbene disulfonic acid, the specific activity of the basic protein was 10 times that of lipophilin. We concluded that the low specific activity of basic protein isolated from the labelled membrane was due to the inaccessible position of this protein in the membrane bilayer.

Amino Acids↗
PubMed1977

Lipid phase separation induced by a hydrophobic protein in phosphatidylserine--phosphatidylcholine vesicles.

Differential scanning calorimetry (DSC) was used to detect phase separation induced by hydrophobic myelin protein, lipophilin, in a mixture of phosphatidylserine (PS) and dipalmitoylphosphatidylcholine (DPPC). Preferential binding of PS to the boundary layer of lipophilin causes a decrease in the PS content of the remaining lamellar phase with a resultant shift in the phase-transition temperature to a higher temperature. The phase diagram for this mixture in the presence and absence of lipophilin is presented. From the phase diagram, it can be estimated that for an equimolar mixture of PS and DPPC, the boundary layer contains only PS, although for higher DPPC contents, some DPPC can also be found in the boundary layer. In the case where partial phase separation in induced in this mixture by Ca2+ alone, lipophilin increases the phase separation indicating that it also binds PS preferentially in the presence of Ca2+. Preferential binding of two other acidic lipids, phosphatidic acid and phosphatidyl-glycerol, to the boundary layer was also found, including a mixture where the acidic lipid was the higher melting component in the mixture.

Calcium↗
PubMed1976

Computerized system analyzes epidemiological data.

The computer is a valuable tool in helping to analyze epidemiological data that are collected through the infection surveillance system. The computerized system described has many significant advantages over the manual system of infection surveillance: quick assimilation, computation, and dissemination of the nosocomial infection summary report (within seven working days of the month's end); identification of infection problems and problem areas; and ability to retrieve data necessary for a complete establishment of a hypothesis regarding cause and effect implicated by an epidemiological investigation. Above all, timely and accurate infection data must be obtained in order for the reports to be beneficial in the decision-making process used by the infection control committee. Manual systems of month-to-month correlation of infection data are difficult and extremely time consuming for the surveillance person. Often the infection control committee cannot act intelligently and quickly because it is not knowledgeable of current trends occurring within the hospital. The computer has a number of limitations, and any computerized surveillance system should be approached with caution, especially during the developmental stages. The computer uses input data, follows instructions, and thus formulates output. If the computer is given either inadequate input data or inaccurately programmed instructions, the output will be erroneous. Therefore, a close working relationship should be established between the epidemiologist and the hospital's data processing department. The goals of the system must be clearly defined and understood by both areas. Once the system is established, the output is only as good as the data supplied by the epidemiologist. If this system is properly utilized, valuable information can be obtained that would have been difficult to obtain using a manual surveillance method.

Communicable Disease Control↗