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Biomedical subjects

C L Johnson

Publications and source records attributed to C L Johnson.

At least 163 records · Page 9Linked to original sources
PubMed1983

A micro-analysis of "senility": the responses of the family and the health professionals.

In research on 167 post-hospitalized older people, thirty individuals were described by their families as being senile. In comparisons of the behaviorally impaired with those who have only a physical condition, it was found that the behaviorally impaired were significantly more likely to be placed in a nursing home than were those with serious physical impairment. In this sub-group, the family also was much more likely to seek-out health professionals for advice in the disposition of the patient, although mental health professionals were rarely consulted. Through a case study analysis, we analyze the interactions between the patients, their families and the health professions as a three-stage process where the patient's behaviors become increasingly specified and elaborated. As a result behaviors formerly tolerated become a formal problem where the solution is likely to be institutionalization.

Aftercare↗
PubMed1983

Autoimmunity and the Kell blood groups: auto-anti-Kpb in a Kp(a+b-) patient.

An example of auto-anti-Kpb in a Kp(a+b-) patient is described. The antibody present in the patient's serum and in eluates from her red cells was IgG. It did not bind complement, and did not cause in vivo hemolysis. 9 months after recognition of the autoimmune state the direct antiglobulin test had become negative and anti-Kpb was no longer detectable. It is postulated that autoimmunity involving the Kell blood group may be precipitated by antigens or enzymes of microbial origin.

Adult↗
PubMed1983

Prevalences of anemia and iron deficiency anemia in Black and White women in the United States estimated by two methods.

Prevalences of anemia were estimated by two methods for 742 Black and 3,074 White nonpregnant women of childbearing age drawn from a large probability sample of the United States civilian noninstitutionalized population (NHANES I). One method defines the prevalence of anemia as the proportion of women with hemoglobin levels below a 12 g/dl "cut-off". The second method defines the prevalence of anemia as the proportion of women whose hemoglobin values are shifted downwards relative to a distribution of hemoglobin values of non-anemic women. Estimates produced by both methods suggest a higher prevalence of anemia in Black than in White women. Estimates produced by the "cut-off" method, however, are higher than those from the "distribution" method for both racial groups, probably because the "cut-off" method results in large overestimates in populations where anemia prevalence is low. The "distribution" method is further used to estimate the contribution of iron deficiency to anemia. Essentially all anemia in White women and a high proportion of anemia in Black women is associated with iron deficiency in the US civilian noninstitutionalized population. Iron supplementation trials are needed in order to define the magnitude of the problem accurately and plan appropriate public health programs.

Adolescent↗
PubMed1982

Inactivation of Kell blood group antigens by 2-aminoethylisothiouronium bromide.

Human red cells incubated with a solution containing 6% 2-aminoethylisothiouronium bromide (AET) lose activity of antigens that are part of, or related to, the Kell blood group system. However, Kx antigen is not inactivated. Studies on a wide range of other blood-group antigens show no other evidence of changes and AET appears to react specifically with red-cell membrane structures that have Kell activity. The AET procedure produces an artificial K0 red cell that can be used in blood group serology, and allows easy recognition of antibodies that are associated with the Kell system. AET has been used by other workers to produce a red cell that has many serological and biochemical characteristics of a PNH cell. Our studies on red cells from PNH patients have not shown any changes in Kell blood-group antigens.

Blood Group Antigens↗
PubMed1981

Elevated serum creatine phosphokinase in subjects with McLeod syndrome.

McLeod phenotype red cells of the Kell blood group system have acanthocytic morphology and reduced in vivo survival. The phenotype has an X-linked mode of inheritance and is found in some males who have no abnormality of leukocyte function and in some who have X-linked chronic granulomatous disease (CGD). We now describe an association between the McLeod phenotype and an abnormal elevation of serum creatine phosphokinase (CPK). The increase is of the MM isoenzyme type, derived from skeletal muscle or cardiac muscle, and muscle biopsy shows evidence of muscle cell changes. All of 11 males who have McLeod syndrome but do not have CGD have high levels of serum CPK. Males with McLeod syndrome and CGD may have normal or high levels of the enzyme. Individuals with other variant phenotypes in the Kell system have normal levels of serum CPK. Studies on a large kindred, which includes 5 people of McLeod phenotype, show high CPK levels only in the members of McLeod type. We conclude that the high level of CPK in the serum of these people is a reflection of a muscle cell anomaly and that in these individuals it is a pleiotropic effect of the X-linked gene that produces the McLeod red cell phenotype.

Anemia, Hemolytic, Congenital↗
PubMed1980

Mosaicism of red cell ABO type without recognizable cause.

A 19-year old woman has been found whose red cells are a mixture of groups A1B (60%) and A1 (40%). Tests for many other genetic markers show no other evidence of mosaicism. She is not a twin and her parents and a sib are of normal ABO type. The cause of her dual population of red cells cannot be established, but may be an effect of somatic crossing over or mutation.

ABO Blood-Group System↗
PubMed1980

Effects of RMI 12330A, a new inhibitor of adenylate cyclase on myocardial function and subcellular activity.

1 RMI 12330A, a lactam-imine, at concentrations of 10(-4) M and higher, inhibited basal as well as isoprenaline and NaF-stimulated adenylate cyclase activity of guinea-pig heart homogenates. However, RMI 12330A was a more potent inhibitor of histamine-stimulated adenylate cyclase (IC50 of 1.5 X 10(-5) M). 2 In the isolated work-performing heart of the guinea-pig, RMI 12330A (IC50 of 1.1 X 10(-6) M) depressed all cardiac functions: pressures developed, dP/dt, contractile force, dF/dt, work performance and stroke work. Left atrial pressure rose and the positive inotropic response to increasing heart rate (staircase) became negative. Histamine, isoprenaline and ouabain no longer caused positive inotropic effects. 3 Increasing the perfusate calcium concentration from 2.5 mM to 4.5 and 6.5 mM completely restored cardiac function after its depression by RMI 12330A. 4 RMI 12330A uncoupled mitochondrial oxidative phosphorylation; the classical uncoupler, dinitrophenol, had the same effects on cardiac dynamics as RMI 12330A. 5 RMI in high doses inhibited hydrolytic activity of Na+, K+-ATPase of crude and purified heart preparations (IC50 of 1.7 X 10(-4) M) and inhibited ouabain binding to the same enzymes (IC50 of 1.5 X 10(-4) M). 6 A lactam-imine analogue of RMI 12330A that had no effect on adenylate cyclase, was also without effect on any of the systems examined.

Adenylyl Cyclase Inhibitors↗
PubMed1980

Calcium dependent regulation of brain and cardiac muscle adenylate cyclase.

The very close interdependence of Ca2+ and hormones in the overall metabolism of cyclic nucleotides has recently been emphasized by Cheung. Clearly the results presented here show that [Ca2+] in the physiological range (less than 10(-7) M to greater than 10(-6) M) has profound effects on the activity of adenylate cyclase from both brain and cardiac muscle. Whereas both brain and cardiac cyclase exhibit a Ca2+ dependent inhibition (perhaps mediated by calmodulin), only the brain cyclase is activated by Ca2+ via calmodulin. With both cyclases there is an inverse relationship between the inhibition of cyclase and the activation of calmodulin dependent (cAMP and cGMP) phosphodiesterase as a function of Ca2+ concentration. Because the IC50's for Ca2+ are the same in both heart and brain, the possibility exists that the Ca2+ inhibitory site of both cyclases is similar and perhaps identical. Considering the ability of Ca2+ to both stimulate and inhibit cyclase, one could imagine that in different species, tissues, or regions of the same tissue, there could exist multiple populations of cyclase, that is a cyclase which would only show Ca2+ dependent inhibition, Ca2+ dependent stimulation, or the biphasic response to Ca2+ (FIGURE 7). The fact that Ca2+ still regulates adenylate cyclase after various stimuli (histamine, NaF, etc.) suggests that Ca2+ may function to regulate the cyclase over shorter time periods (regardless of its state of stimulation) and that other affectors of cyclase (e.g., hormones) would serve to regulate the cyclase over longer time periods.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1980

Familial hypersensitivity pneumonitis induced by Bacillus subtilis.

Six members of one family developed symptoms consistent with hypersensitivity pneumonitis after exposure to wood dust generated during the remodeling of a bathroom in their house. A detailed microbiologic investigation of the house and surrounding areas resulted in the isolation of 2-Bacillus species. The vegetative cell and spore extracts of these organisms were used for extensive in vivo and in vitro laboratory tests. All symtomatic members of the family demonstrated positive bronchoprovocation responses to vegetative cell extracts of B. subtilis. Two patients with clinical disease exhibited immediate positive skin tests to similar extracts. Positive lymphoproliferative responses to the vegetative cell extract of B. subtilis were observed in 4 of 5 symptomatic patients and in 1 additional patient tested with the spore form of B. subtilis. It is postulated that the abrupt appearance of this family epidemic depended on the special circumstance of continued exposure to high concentrations of B. subtilis organisms within the household. B. subtilis should be added to the list of antigens causing hypersensitivity penumonitis. Prompt recognition and elimination of this new causal agent could prevent irreversible lung damage in susceptible patients.

Adolescent↗