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Biomedical subjects

C Johnson

Publications and source records attributed to C Johnson.

At least 379 records · Page 21Linked to original sources
PubMed1989

Humoral immunity and clinical reinfections following varicella vaccine in healthy children.

The duration of immunity following varicella-zoster vaccination in healthy children remains a critical issue. In a 3-year study of 140 OKA/Merck vaccine recipients, duration of immunity was assessed by two measures. The first was persistence of varicella-zoster antibody measured by modified fluorescent antibody to membrane antigen test. Thirty-six toddler vaccinees 12 to 24 months of age had sera obtained at 6 weeks, 1 year, and 2 years. Geometric mean titer +/- SD at 6 weeks was 57.7 +/- 2.9; at 1 year, it was 12.4 +/- 3.9; at 2 years, it was 9.9 +/- 3.9. Repeated-measures analysis of variance showed a significant overall decrease in antibody titer with time (F = 30.62, P less than .001). Post hoc comparisons indicated that the 6-week and 1-year titers were significantly different (P less than .001), but the difference between 1 and 2 years was not (P = .138). Clinical reinfections were also examined for 3 years after vaccination. Suspected varicella cases were confirmed by a fourfold or more increase in titer. Of 84 toddlers, 68 were exposed one or more times, and 6 became reinfected. Of 49 siblings, 45 were exposed, and one became reinfected. All 7 children had less than 70 vesicles and 6 of 7 were afebrile. No cases of zoster occurred. It is concluded that OKA/Merck varicella-zoster vaccination leads to antibody persistence for 2 years and the few reinfections that do occur are greatly attenuated.

Antibodies, Viral↗
PubMed1989

Association between bacterial vaginosis and acute cystitis in women using diaphragms.

We hypothesized that the increased vaginal fluid pH and altered vaginal microflora characteristic of bacterial vaginosis might predispose young women to introital colonization with Escherichia coli and to acute cystitis. To evaluate this hypothesis, we studied 291 women who presented with acute urinary symptoms for association of clinically defined bacterial vaginosis and vaginal conditions associated with this syndrome (increased vaginal fluid pH, absence of lactobacilli, and abnormal vaginal fluid gas-liquid chromatographic patterns) with E coli introital colonization and urinary tract infection. Escherichia coli introital colonization and urinary tract infection were both significantly more frequent among women with a high vaginal fluid pH, an absence of vaginal lactobacilli, or an abnormal vaginal fluid gas-liquid chromatographic pattern characteristic of bacterial vaginosis. Escherichia coli introital colonization was also more frequent in women with bacterial vaginosis. These associations and an association of bacterial vaginosis and E coli urinary tract infection were strong only among the 144 women who were diaphragm users. We conclude that bacterial vaginosis, or an altered vaginal microflora as reflected by an abnormal gas-liquid chromatographic pattern characteristic of bacterial vaginosis, is associated with E coli introital colonization and acute symptomatic urinary tract infection in women who use diaphragms.

Acute Disease↗
PubMed1989

Electrophoresis combined with immunologic identification of human tear proteins.

The protein content of normal human tears from five subjects was examined by molecular weight separation using SDS-polyacrylamide gel electrophoresis (PAGE) and by charge separation using agarose isoelectric focusing (IEF) gels. After separation, specific proteins were identified by immunoblot and immunofixation. Tear proteins examined included albumin, IgA, IgG, prealbumin, lactoferrin, lysozyme, secretory component and transferrin. These techniques required 1 to 14 microliters unconcentrated tears. We found SDS-PAGE superior to agarose IEF to examine total tear protein pattern, and silver stain almost ten-fold more sensitive than Coomassie blue stain. Immunologic staining markedly enhanced protein detection in all tear samples and appeared to offer the definitive method to probe for a specific protein in tears. In this study prealbumin and a portion of the IgG were present in normal tears at higher than expected molecular weight, suggesting they were present in complexed form. Prealbumin and secretory component staining showed marked variability between subjects. These techniques should be applicable to examine tear proteins in a variety of ocular disease states.

Adult↗
PubMed1989

Prevalence and clinical characteristics of borderline patients in an eating-disordered population.

Ninety-four consecutive patients seeking treatment for eating disorders were evaluated for eating attitudes and behaviors, weight history, psychiatric symptoms, psychosocial stressors, social adaptation, family environment, and the presence of borderline personality organization. The patients were divided into borderline and nonborderline groups and were compared on the above dimensions, with 46% of the patients showing borderline personality features. The borderline patients and the nonborderline patients had relatively few differences in the severity of their symptomatic eating behaviors and attitudes. The borderline patients, however, were significantly more disturbed on a number of relevant dimensions, including general psychiatric symptoms, psychosocial adaptation, family environment, self-destructive behavior, and treatment history. The authors suggest, on the basis of their findings and the findings of previous studies, that about one third of eating-disordered patients have marked borderline characteristics. They recommend that research studies in the future control for the eating-disordered patients' character pathologies. They also recommend that clinicians use a combination of long-term relationship-oriented treatment and psychopharmacological treatment with eating-disordered patients who have borderline personality disorder.

Adolescent↗
PubMed1988

The Escherichia coli biotin biosynthetic enzyme sequences predicted from the nucleotide sequence of the bio operon.

The nucleotide sequence of the biotin (bio) biosynthetic operon of Escherichia coli has been determined. The 5.8-kilobase region contains the five biotin operon genes, bioA, B, F, C, and D. and an open reading frame of unknown function. The operon is negatively regulated and divergently transcribed from a control region between the bioA and bioB genes. The product of the bioA gene, 7,8-diaminopelargonic acid aminotransferase, was discovered to be related to ornithine aminotransferase. The product of the bioF gene, 7-keto-8-aminopelargonic acid synthetase, was found to be similar to 5-aminolevulinic acid synthetase.

5-Aminolevulinate Synthetase↗
PubMed1988

Adherence induces selective mRNA expression of monocyte mediators and proto-oncogenes.

Adherence is an important regulatory signal for several monokines and the proto-oncogenes c-fms and c-fos in human peripheral blood monocytes. Although there is little if any constitutive expression of the IL-1 beta, TNF-alpha and CSF-1 genes in freshly isolated monocytes, adherence is sufficient to induce high steady-state levels of mRNA for TNF and c-fos and more slowly that of CSF-1. Expression of mRNA for the CSF-1R gene, c-fms, was transiently down-regulated by 4 h. In contrast, the induction of high levels of IL-1 beta mRNA were achieved independent of culture conditions. Although all of these genes could be induced by adherence, actual secretion of the mediators required the exposure to a second signal derived from LPS. Thus adherence rapidly primes monocytes for a variety of inflammatory responses, the magnitude of which depends on the nature of a second "activating" signal. It is likely that some of these products act locally as paracrine or autocrine factors to further regulate the phenotype of the differentiating macrophage.

Cell Adhesion↗
PubMed1988

Measurement of immunoreactive myelin basic protein peptide (45-89) in cerebrospinal fluid.

To measure myelin basic protein (MBP)-like material in cerebrospinal fluid, we compared two radioimmunoassays, both using the same antiserum to MBP but one using peptide (45-89) as the radioligand and standard (peptide assay), and the other using purified MBP as the radioligand and standard (MBP assay), with respect to their diagnostic sensitivity. Cerebrospinal fluid specimens from 185 patients with definite multiple sclerosis (MS) (n = 27), possible MS (n = 63), probable MS (n = 24), and other neurological disease (n = 71) were analyzed using both assays. The diagnostic sensitivity of the peptide assay was significantly better than that of the MBP assay in those with definite MS (sensitivity 59% and 30%, respectively); there was no significant difference in specificity. The peptide assay also showed better correlation with disease activity than the MBP assay: 14 patients classified as having active MS showed significantly higher sensitivity (78.6% versus 38%, p less than 0.04) when compared to patients with inactive disease. The MBP assay showed no significant difference between these two groups. Besides the increase in sensitivity, the actual molar concentrations of immunoreactive MBP detected using this peptide assay were considerably higher than those found using the MBP assay. These results show that the use of MBP antisera capable of recognizing epitopes present in the carboxyl half of MBP peptide (45-89) results in more sensitive detection of immunoreactive MBP when used with MBP peptide (45-89) as radiolabeled ligand in the assay.

Humans↗
PubMed1988

Parameter identification of the human lower limb under dynamic, transient torsional loading.

The response of the lower limb to dynamic, transient torsional loading applied at the foot has been measured for a male test subject. The dynamic loading was provided by a computer controlled pneumatic system which applied single haversine (i.e. half cycle of a sine wave) axial moment pulses of variable amplitude (0-100 Nm) and duration (50-600 ms). Potentiometers measured the absolute rotations of the three leg segments. Test variables included rotation direction, weight bearing and joint flexion. Two approaches were explored for specifying parameters (i.e. inertia, damping, stiffness) of a three degree-of-freedom dynamic system model which best duplicated the measured response. One approach involved identification of linear parameters by means of optimization while the other approach entailed estimation. Parameter estimates, which included non-linear, asymmetric stiffness functions, were derived from the literature. The optimization was undertaken so as to identify parameter dependence on test variables. Results indicate that parameter values are influenced by test variables. Results also indicate that the non-linear, estimated model better approximates the experimental data than the linear, identified model. In addition to identifying parameters of a three degree-of-freedom model, parameters were also identified for a single degree-of-freedom model where the motion variable was intended to indicate the rotation of the in vivo knee. It is concluded that the simpler model offers good accuracy in predicting both magnitude and time of occurrence of peak knee axial rotations. Model motion fails to track the measured knee rotation subsequent to the peak, however.

Ankle Joint↗
PubMed1988

The production of C3, PGE2 and TxB2 by splenic, alveolar, and peritoneal guinea pig macrophages.

The synthesis and release of C3, PGE2, and TxB2 by cultured splenic, alveolar and peritoneal guinea pig macrophages in 24 hour culture was determined. There were significant differences in C3 production among all three sources of macrophages. Splenic macrophages produced significantly less PGE2 than alveolar or peritoneal macrophages. Peritoneal macrophages produced significantly more TxB2 than splenic or alveolar macrophages. The cells from the different sources appear to be different populations of macrophages.

Animals↗
PubMed1988

Comparison of active and combined passive/active immunization of Navajo children against Haemophilus influenzae type b.

In a high risk Navajo population we compared the immunogenicity of a new Haemophilus influenzae type b mutant-diphtheria toxic conjugate vaccine (HbOC) with simultaneous active (HbOC) and passive immunization with bacterial polysaccharide immunoglobulin prepared from adults immunized with H. influenzae b, pneumococcal and meningococcal vaccines. Only 7 of 26 (27%) 2-month-olds had an increase in H. influenzae b capsular polysaccharide antibody after a single dose of HbOC, a proportion similar to that of saline controls (9 of 25, 36%). After a second HbOC dose at 4 months 88% had antibody concentrations of 0.15 microgram or more, and after a third dose at 6 months all had antibody levels greater than or equal to 0.15 microgram/ml. The group receiving both HbOC and bacterial polysaccharide immunoglobulin at 2 months uniformly had H. influenzae b CP antibody concentrations of greater than or equal to 0.15 microgram/ml at 4 months (P less than 0.001 relative to "HbOC alone" group) and subsequently responded similarly to second and third doses of HbOC vaccine as did also the "HbOC alone" group. We conclude that combined passive/active immunization with bacterial polysaccharide immunoglobulin and HbOC at 2 months maintains antibody at concentrations thought to be protective (greater than or equal to 0.15 microgram/ml) without interfering with the active antibody response to second and third doses of HbOC at 4 and 6 months of age.

Bacterial Capsules↗
PubMed1988

Intraparenchymal brain metastases: MR imaging versus contrast-enhanced CT.

Prospective and retrospective studies of 75 patients were performed to assess the sensitivities of magnetic resonance (MR) imaging and computed tomography (CT) in the evaluation of suspected intraparenchymal brain metastases. The findings on MR images were equivalent to those on CT scans in 49 of the 75 patients; the remaining findings were discordant in 26 patients, and neither MR imaging nor CT was consistently superior. MR imaging demonstrated more metastases in nine of these 26 patients. However, contrast material-enhanced CT scans were superior in lesion depiction in eight of the 26 patients. Large enhanced lesions that were nearly isointense on MR images were seen well on CT scans. In several cases in which results were discordant, gadolinium-diethylenetriaminepentaacetic acid (DTPA)-enhanced MR images were obtained, and this agent behaved similarly to iodinated contrast agents. If indicated clinically, such as before surgery for a single metastasis, the authors perform both MR imaging and contrast-enhanced CT. Gd-DTPA-enhanced MR imaging may prove to be the method of choice for depiction of intraparenchymal metastases.

Adolescent↗
PubMed1988

Trimethoprim-sulfamethoxazole for acute dysuria in women: a single-dose or 10-day course. A double-blind, randomized trial.

STUDY OBJECTIVE: To compare single-dose and 10-day treatment regimens of trimethoprim-sulfamethoxazole in women with acute dysuria, urgency, or urinary frequency. DESIGN: Double-blind, randomized, placebo-controlled trial. SETTING: Student health center at a major university. PATIENTS: Consecutive sample of 255 young women including 216 with a bacteriologically documented urinary tract infection. INTERVENTION: Single-dose treatment (trimethoprim, 320 mg and sulfamethoxazole, 1600 mg) given to 116 women and 10-day treatment (trimethoprim, 160 mg and sulfamethoxazole, 800 mg, twice daily) given to 125 women. Women with a history of sulfonamide allergy were given trimethoprim alone: 10 received single-dose treatment (200 mg) and 5 received 10-day treatment (100 mg, twice daily). MEASUREMENTS AND MAIN RESULTS: The rates for resolution of symptoms at 3 days, 13 days, and 6 weeks after entry into the study were not significantly different between treatment groups. Among women with urinary tract infections, cumulative crude rates of recurrence in the single-dose and 10-day treatment groups, respectively, were 24% compared with 5% at 13 days after entry (P = 0.0002; 95% confidence interval [CI] for difference in proportions, 10%, 28%) and 32% compared with 21% at 6 weeks after entry (P = 0.07; 95% Cl, -2%, 24%). Factors independently associated with lower cure rates were a history of a urinary tract infection within the previous 6 weeks (adjusted odds ratio [OR], 3.8; 95% Cl, 1.4 to 10.6) and presence of 10(5) bacteria/mL or greater in an initial midstream culture (adjusted OR, 2.9; 95% Cl, 1.2 to 7.0). After controlling for these factors, the risk of failure after single-dose treatment was not statistically significantly different from 10-day treatment at 6 weeks (adjusted OR, 1.6; 95% Cl, 0.8 to 3.2; P = 0.21). Compared to 10-day treatment, single-dose treatment less effectively eradicated Escherichia coli from the vaginal flora (P less than 0.001) and led more often to early same-strain recurrences (P = 0.003). Meaningful adverse effects occurred in 12% of women given single-dose treatment compared with 25% of women receiving 10-day treatment (P = 0.009). CONCLUSIONS: Compared with single-dose treatment, 10-day treatment yields a superior cure rate at 2 weeks after the start of treatment, but by 6 weeks the advantage of longer treatment no longer exists. This effect may be explained by the lesser effectiveness of single-dose treatment in eradicating vaginal E. coli, resulting in more frequent same-strain recurrences within 2 weeks of treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗