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Biomedical subjects

R B Johnson

Publications and source records attributed to R B Johnson.

At least 163 records · Page 9Linked to original sources
PubMed1982

The application of enzyme immunoassay to the study of salivary IGA.

In the study of salivary IgA, solid-phase enzyme immunoassay has been able to show that 1) the assay is reliable, 2) minimal loss of IgA occurs from centrifuging or by elimination of insoluble mucins, 3) IgA can be easily measured in fractions from sucrose gradient sedimentation, 4) freezing alone is sufficient to preserve salivary IgA, 5) the concentration in normal saliva in 11 persons ranged from 15 to 240 mg/L (-/x = 81), and 6) an abnormal saliva contained less than 6 ug/L, the detection limit for this EIA.

Adult↗
PubMed1982

IgG and IgM antibodies to rubella quantitated by enzyme immunoassay.

A solid-phase enzyme immunoassay for rubella antibodies (of IgG, H & L type, IgM-type) is described that requires assay at usually one dilution of serum. Results are reportable in milligrams IgG (or IgM)--equivalents per liter serum and in approximate hemagglutination inhibition (HAI) titers. The method uses purified rubella virus immobilized by a special process in excess, a 16 to 18 h first incubation at 20 degrees C, and a glucose-oxidase labeled second antibody to obtain 97% agreement with HAI. IgM-class antibodies are assayed after a preliminary separation from IgG by ion exchange to obtain results equivalent to those obtained after sucrose gradient sedimentation.

Antibodies, Viral↗
PubMed1982

B-lymphocyte mitogenicity in vitro of a synthetic lipopeptide fragment derived from bacterial lipoprotein.

Lipoprotein from the outer membrane of Escherichia coli is a potent mitogen towards lymphocytes of different species. A lipopeptide fragment corresponding to the N-terminal part of the lipoprotein was prepared by chemical synthesis. The mitogenicity of the compound was demonstrated by measuring the incorporation of both [3H]thymidine into DNA and [3H]uridine into RNA at various times after the addition of lipopeptide to mouse spleen cell cultures. The lipopeptide also activated B-lymphocyte development into immunoglobulin secreting cells, as shown by a hemolytic plaque assay. The mitogenicity of the synthetic compound was comparable to the activity of the B-lymphocyte mitogens lipoprotein and lipopolysaccharide. Thus, it was shown that a fragment of a bacterial surface component prepared by chemical synthesis, exhibits a marked biological activity.

Animals↗
PubMed1981

Acid phosphatase activity in the cytosol fraction of the breast cancer tissue.

Acid phosphatase activity was studied in the cytosol fraction of breast cancer tissue. Serum, plasma, and extracts of leukocyte and platelet were used for reference. The breast cancer tissue fraction had an electrophoretic mobility intermediate to leukocyte-derived bands 2 and 4 and corresponding to the platelet-derived band 3. The enzymes derived from platelet and breast cancer tissue were both inhibited by L-tartrate and showed a similar pattern for preferred substrates. By contrast, the breast cancer tissue-derived enzyme was different from the enzyme fraction responsible for the elevated serum enzyme activity in some patients with disseminated breast cancer. The two fractions could be distinguished by electrophoretic mobility and tartrate sensitivity. These findings substantiate our previous report, which suggested that the fraction responsible for elevated serum enzyme activity in the course of breast cancer is not derived from cancer tissue. It is proposed that the osteolysis, resulting from bone metastases, may be responsible for elevated serum enzyme activity in this disease.

Acid Phosphatase↗
PubMed1981

Development of transalveolar fibres in alveolar bone of the mouse.

Transalveolar fibre development in the mandibles of albino mice aged 12-32 days postnatal was studied. Silver impregnation techniques revealed transalveolar fibres in the alveolar crest bone at day 14 and throughout the interdental septum at day 17. Collagen strains revealed transalveolar fibres in alveolar crest bone at day 19 and throughout the interdental bone by day 25. Changes in orientation occurred in transalveolar fibres of the alveolar crest at day 19 and in oblique transalveolar fibres at day 25. These changes were coincident with the eruption of the teeth and the development of functional occlusion.

Alveolar Process↗
PubMed1981

Dilantin digital defects.

Diphenylhydantoin (phenytoin) is a widely used drug with multiple adverse effects, several of them cutaneous. Prenatal exposure to hydantoins may result in a spectrum of structural, developmental, and behavioral changes known as the fetal hydantoin syndrome (FHS). A patient with the dysmorphic characteristics of FHS had unusual hyperpigmentation of several fingernails, a finding which has not been described in other patients with FHS. We propose a mechanism for the dysmorphic action of phenytoin on the developing fetus, consonant with the known effects of hydantoins on collagen metabolism.

Abnormalities, Drug-Induced↗
PubMed1980

Comparison of glucose oxidase and peroxidase as labels for antibody in enzyme-linked immunosorbent assay.

Horse-radish peroxidase and glucose oxidase were each separately conjugated to identical aliquots of goat IgG containing anti-human IgG antibodies. We used a minor modification of the periodate method of Nakane and Kawaoi to covalently bind each enzyme to IgG. Glucose oxidase conjugates proved superior to peroxidase conjugates based on the following qualities. The glucose oxidase conjugates had 1) usable dilutions 2 to 10 times greater than peroxidase conjugates, 2) much lower background or control non-specific activities, and 3) nearly twice the sensitivity as expressed by absorbance change vs. change in antigen. Comparison of the antibody titers showed the glucose oxidase conjugate with 80% and the peroxidase conjugate with 20% of the original goat antibody.

Animals↗
PubMed1980

Separation of immunoglobulin M (IgM) essentially free of IgG from serum for use in systems requiring assay of IgM-type antibodies without interference from rheumatoid factor.

The proposed method was designed to replace the tedious and difficult separation of immunoglobulin M (IgM) from IgG by sucrose gradient sedimentation. In this method, a 250-microliter portion of serum diluted 20-fold was passed through a small column of quaternary aminoethyl-Sephadex A-50 ion exchanger. IgG was not retained, but additional washes were required to remove all but 5%. A second buffer-eluting fluid recovered an average of 80% of the original IgM in a defined dilution. The entire operation took 15 min. The efficiency of this process was evaluated by the following: (i) radial immunodiffusion measurements of IgG and IgM; (ii) recovery studies of isohemagglutinins; and (iii) demonstrated removal of interference by the rheumatoid factor. The method was applied successfully to distinguish rubella IgM antibody.

Antibodies, Viral↗
PubMed1978

Immune electron microscopy of avian infectious bronchitis virus serotypes.

An immune electron microscopy agglutination technique in which emphasis is placed upon the importance of antigen-antibody equivalence has been developed as a possible method for the serotyping of avian infectious bronchitis viruses. The Connecticut and Massachusetts 41 serotypes were used as a model system. Stock virus concentrations were standardized by physical particle counts of virions sedimented directly onto electron microscope specimen grids. Suspensions containing approximately 150 virions per grid square were allowed to react with dilutions of homologous and heterologous antisera. Virions in these constant virus-variable serum mixtures were sedimented directly onto electron microscope specimen grids, and the relative degree of aggregation per grid was determined from the mean percent aggregation of five randomly selected grid squares. In homologous assays, regions of relative antibody excess, of equivalence, and of relative antigen excess were clearly evident. At equivalence, the mean percent aggregation was significantly higher than in the regions of relative antibody or antigen excess. In the heterologous systems, the degree of aggregation differed little from that of the virus controls containing no antiserum.

Agglutination Tests↗
PubMed1977

Improved estrogen receptor assay in human mammary cancer. Technics for handling small tissue samples.

Studies of various technics that aid in performing estrogen receptor assays on small tissue samples from primary cancers of the breast are reported. It is shown how sufficient protein can be obtained from less than 100 mg of small primary tumor without ultracentrifugation to assay estrogen receptor by a simplified two-point Scatchard plot method. The resulting Kd and maximum binding site values with 36 tumor tissue samples approximated the values obtained with the more laborious, larger tissue sample-demanding six-point Scatchard plot. Target and nontarget tissue controls are easily included in an assay run of four to eight samples. For interpretive purposes the derivation of the characterizing value of the Kd for estrogen receptor is given and compared with nonspecific associating binders.

Animals↗
PubMed1977

Effects of frequency and duration of training on attrition and incidence of injury.

Eighty-seven male inmates from a state prison and 70 inmates from a county jail volunteered as subjects. The subjects, age 20 to 35 yrs, were assigned randomly into a control or exercise group. Their Vo2max and treadmill performance values were determined before and after a 20 week jogging program. Training intensity was between 85 and 90 percent of maximum heart rate and involved workouts 3 days/week for 15, 30, or 45-min duration at the state prison and for 30-min 1, 3, or 5 days/week at the country jail. Cardiorespiratory fitness improved in direct proportion to frequency and duration of training. Injury, occurred in 22%, 24% and 54% of the 15, 30, and 45-min duration groups and in 0%, 12%, and 39% of the 1, 3, and 5-day/week groups, respectively. Attrition resulting from injury occurred in 0%, 0%, and 17% and in 0%, 4%, and 6% of the same respective groups. Attrition due to lack of interest was similar for all training groups (25%), but was significantly lower in the control groups (10%). Although the results showed a greater increase in cardiorespiratory fitness for the 45-min duration and 5-day/week groups, these programs are not recommened for beginning joggers because of the significantly greater percent of injuries.

Adult↗