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Biomedical subjects

C J Johnson

Publications and source records attributed to C J Johnson.

At least 19 recordsLinked to original sources
PubMed2002

Relationship of fertility to ovarian follicular waves before breeding in dairy cows.

Cows with two waves of follicular growth during the estrous cycle yield follicles that are older and larger at ovulation compared with cows having three waves. The objectives of the current research were 1) to compare fertility in cows with two or three follicular waves and 2) to examine associations between luteal function, follicular development, and fertility after breeding. Follicular waves were monitored by ultrasonography during the estrous cycle before insemination in 106 dairy cows. Fewer cows had three follicular waves before next estrus and ovulation than two waves (P < 0.01; 30% vs 68%, respectively), but pregnancy rate was higher (P = 0.058; 81 vs 63%, respectively). Cows with two waves had shorter estrous cycles (P < 0.01), with the ovulatory follicle being both larger (P < 0.05) and older (P < 0.01). In cows with three waves, luteal function was extended (P < 0.05) and the peak in plasma progesterone occurred later (P < 0.05) in the estrous cycle compared to two wave cows. Considering cows that became pregnant, luteal phase length was shorter (P < 0.05) during the estrous cycle preceding insemination than for nonpregnant cows. In conclusion, fertility was greater in lactating cows inseminated after ovulation of the third-wave follicle that had developed for fewer days of the estrous cycle as compared with two-wave cows.

Animals↗
PubMed2001

Effect of ramipril vs amlodipine on renal outcomes in hypertensive nephrosclerosis: a randomized controlled trial.

CONTEXT: Incidence of end-stage renal disease due to hypertension has increased in recent decades, but the optimal strategy for treatment of hypertension to prevent renal failure is unknown, especially among African Americans. OBJECTIVE: To compare the effects of an angiotensin-converting enzyme (ACE) inhibitor (ramipril), a dihydropyridine calcium channel blocker (amlodipine), and a beta-blocker (metoprolol) on hypertensive renal disease progression. DESIGN, SETTING, AND PARTICIPANTS: Interim analysis of a randomized, double-blind, 3 x 2 factorial trial conducted in 1094 African Americans aged 18 to 70 years with hypertensive renal disease (glomerular filtration rate [GFR] of 20-65 mL/min per 1.73 m(2)) enrolled between February 1995 and September 1998. This report compares the ramipril and amlodipine groups following discontinuation of the amlodipine intervention in September 2000. INTERVENTIONS: Participants were randomly assigned to receive amlodipine, 5 to 10 mg/d (n = 217), ramipril, 2.5 to 10 mg/d (n = 436), or metoprolol, 50 to 200 mg/d (n = 441), with other agents added to achieve 1 of 2 blood pressure goals. MAIN OUTCOME MEASURES: The primary outcome measure was the rate of change in GFR; the main secondary outcome was a composite index of the clinical end points of reduction in GFR of more than 50% or 25 mL/min per 1.73 m(2), end-stage renal disease, or death. RESULTS: Among participants with a urinary protein to creatinine ratio of >0.22 (corresponding approximately to proteinuria of more than 300 mg/d), the ramipril group had a 36% (2.02 [SE, 0.74] mL/min per 1.73 m(2)/y) slower mean decline in GFR over 3 years (P =.006) and a 48% reduced risk of the clinical end points vs the amlodipine group (95% confidence interval [CI], 20%-66%). In the entire cohort, there was no significant difference in mean GFR decline from baseline to 3 years between treatment groups (P =.38). However, compared with the amlodipine group, after adjustment for baseline covariates the ramipril group had a 38% reduced risk of clinical end points (95% CI, 13%-56%), a 36% slower mean decline in GFR after 3 months (P =.002), and less proteinuria (P<.001). CONCLUSION: Ramipril, compared with amlodipine, retards renal disease progression in patients with hypertensive renal disease and proteinuria and may offer benefit to patients without proteinuria.

Adrenergic beta-Antagonists↗
PubMed2001

The role of neck dissection after chemoradiotherapy for oropharyngeal cancer with advanced nodal disease.

OBJECTIVE: To analyze and compare the effectiveness of sequential platinum-based chemotherapy and radiotherapy with and without selective neck dissection in patients with N2a and greater stage node-positive squamous cell carcinoma of the oropharynx. DESIGN: Nonrandomized controlled trial. SETTING: Tertiary referral center. PATIENTS: Sixty-six patients with squamous cell carcinoma of the oropharynx staged N2a or greater. INTERVENTIONS: Platinum-based induction chemotherapy followed by definitive radiation therapy; and selective neck dissections 6 to 10 weeks following the completion of radiation therapy in patients with radiographic evidence suggesting residual neck disease. MAIN OUTCOME MEASURES: Locoregional recurrence and disease-free survival. RESULTS: Of 66 patients, 24 (36%) had complete responses in the primary local tumor (oropharynx) and regional disease (neck nodes), as assessed clinically and radiographically. These patients had lower rates of locoregional recurrence than did patients showing no or partial responses, but the differences were not significant (P>.05). Of 18 patients undergoing neck dissection, 10 (56%) had pathological evidence of residual tumor. Patients showing a complete response of regional and neck disease had significantly improved disease-specific and overall survival (P = .01 for both) compared with patients showing no or partial responses of their neck disease. Patients with no or partial responses who underwent neck dissections had significantly improved overall survival compared with similar patients who did not undergo neck dissections (P = .002). CONCLUSIONS: Even in patients with bulky nodal disease, a complete response in the neck to sequential chemotherapy and radiotherapy may indicate that neck surgery is not necessary for good locoregional control and improved disease-free survival. Neck dissection is recommended for patients with no or partial radiographic responses.

Adult↗
PubMed2001

Comorbidity of psychiatric and substance use disorders in late adolescence: a cluster analytic approach.

Cluster analysis was used to identify subgroups of youths with past-year substance and/or psychiatric disorders (N = 110, mean age 19.0 years). Data for this study came from a community-based, prospective longitudinal investigation of speech/language (S/L) impaired children and matched controls who participated in extensive diagnostic and psychosocial assessments at entry into the study at 5 years of age and again at follow-up. Clustering variables were based on five DSM diagnostic categories assessed at age 19with the University of Michigan Composite International Diagnostic Interview. Using Ward's method, the five binary variables were entered into a hierarchical cluster analysis. An iterative clustering method (K-means) was then used to refine the Ward solution. Finally, a series of analyses of variance (ANOVAs) were run to analyze group differences between clusters on measures of Global Assessment of Functioning (GAF), criminal involvement, anxiety and depressive symptomatology, and frequency of drug use and heavy drinking. The analysis yielded eight replicable cluster groups, which were labeled as follows: (a) anxious (20.9%); (b) anxious drinkers (5.5%); (c) depressed (16.4%); (d) depressed drug abusers (10%); (e) antisocial (16.4%); (f) antisocial drinkers (10%); (g) drug abusers (8.2%); (h) problem drinkers (12.7%). These groups were differentiated by external criteria, thus supporting the validity of our cluster solution. Cluster membership was associated with a history of S/L impairment: A large proportion of the depressed drug abusers and the antisocial cluster group had S/L impairment that was identified at age 5. Clarification of the developmental progress of the youths in these cluster groups can inform our approach to early intervention and treatment.

Adolescent↗
PubMed2001

Mathematical model of antibody targeting: important parameters defined using clinical data.

Antibody-targeted therapy of cancer has shown benefits in the treatment of some cancers but selective delivery has not been optimized. Many parameters influence antibody targeting; some will have a greater effect than others and their effects will generally be interrelated. They include effects of blood flow and pressure, vascular permeability, venous and lymphatic drainage, permeation through extravascular spaces, antibody clearance, specificity, affinity and resistance to degradation. Quantitative data about the behaviour of targeting systems can be collected, and it is possible to describe the system in terms of compartments interconnected by equations defining the passage of targeting agents between them. A mathematical model of antibody targeting can thus be built. We have collected data on the time course of the distribution of four different antibody molecules of molecular weight 27, 100 and 150 kDa directed against carcinoembryonic antigen in patients with colorectal cancer. Laboratory data were used for parameters which could not be measured in patients. These data have been used to test the validity of the model for man and to develop it so that it is consistent with the diverse clinical data. The model is then used to understand the effects of changes to a parameter on tumour targeting efficiency and to select those parameters which have the greatest effect in therapy. Affinity of antibody, flow of antibody through the tumour and rate of elimination of antibody from the tumour were shown to be the most powerful parameters determining antibody localization. These concepts can be used to determine design parameters for antibody-targeted cancer therapy.

Antigen-Antibody Reactions↗
PubMed2001

Fourteen-year follow-up of speech/language-impaired and control children: psychiatric outcome.

OBJECTIVE: To examine the association between early childhood speech and language disorders and young adult psychiatric disorders. METHOD: In a longitudinal community study conducted in the Ottawa-Carleton region of Ontario, Canada, interviewers administered structured psychiatric interviews to age 19 participants who were originally identified as speech-impaired only, language-impaired, or nonimpaired at age 5. The first stage of the study took place in 1982 when participants were 5 years old, and the latest stage of the study took place between 1995 and 1997 when participants had a mean age of 19 years. This report examines the association between early childhood speech/language status and young adult psychiatric outcome. RESULTS: Children with early language impairment had significantly higher rates of anxiety disorder in young adulthood compared with nonimpaired children. The majority of participants with anxiety disorders had a diagnosis of social phobia. Trends were found toward associations between language impairment and overall and antisocial personality disorder rates. Males from the language-impaired group had significantly higher rates of antisocial personality disorder compared with males from the control group. Age of onset and comorbidity did not differ by speech/language status. The majority of participants with a disorder had more than one. CONCLUSIONS: Results support the association between early childhood speech and language functioning and young adult psychiatric disorder over a 14-year period. This association underscores the importance of effective and early interventions.

Adult↗
PubMed2001

Alcohol intake, type of beverage, and the risk of cerebral infarction in young women.

BACKGROUND AND PURPOSE: The relationship between alcohol consumption and cerebral infarction remains uncertain, and few studies have investigated whether the relationship varies by alcohol type or is present in young adults. We examined the relationship between alcohol consumption, beverage type, and ischemic stroke in the Stroke Prevention in Young Women Study. METHODS: All 59 hospitals in the greater Baltimore-Washington area participated in a population-based case-control study of stroke in young women. Case patients (n=224) were aged 15 to 44 years with a first cerebral infarction, and control subjects (n=392), identified by random-digit dialing, were frequency matched by age and region of residence. The interview assessed lifetime alcohol consumption and consumption and beverage type in the previous year, week, and day. ORs were obtained from logistic regression models controlling for age, race, education, and smoking status, with never drinkers as the referent. RESULTS: Alcohol consumption, up to 24 g/d, in the past year was associated with fewer ischemic strokes (<12 g/d: OR 0.57, 95% CI 0. 38 to 0.86; 12 to 24 g/d: OR 0.38, 95% CI 0.17 to 0.86; >24 g/d: OR 0.95, 95% CI 0.43 to 2.10) in comparison to never drinking. Analyses of beverage type (beer, wine, liquor) indicated a protective effect for wine consumption in the previous year (<12 g/wk: OR 0.58, 95% CI 0.35 to 0.97; 12 g/wk to <12 g/d: OR 0.55, 95% CI 0.28 to 1.10; >/=12 g/d: OR 0.92, 95% CI 0.23 to 3.64). CONCLUSIONS: Light to moderate alcohol consumption appears to be associated with a reduced risk of ischemic stroke in young women.

Adolescent↗
PubMed2001

Etanercept in juvenile rheumatoid arthritis.

OBJECTIVE: To review the classification, pathophysiology, safety, and efficacy of treatment options for juvenile rheumatoid arthritis (JRA). Etanercept, the agent most recently approved by the Food and Drug Administration for use in JRA, is featured. DATA SOURCES: Articles were identified from a search of the MEDLINE database (1966 to January 2000) and through secondary sources. Meeting abstracts and posters were also evaluated. STUDY SELECTION AND DATA EXTRACTION: Articles identified and retrieved from data sources were evaluated and, if determined to be relevant, were included in this review. DATA SYNTHESIS: JRA represents a major cause of functional disability in children. In contrast to traditional therapeutic agents for JRA, which act through generalized antiinflammatory activity or generalized immunosuppression, new therapeutic modalities have been developed that target specific molecules involved in the pathophysiology of JRA. Etanercept inhibits the activity of tumor necrosis factor and lymphotoxin-alpha. In a clinical trial of patients with polyarticular-course JRA, etanercept-treated patients experienced less pain and swelling in their joints, decreased incidence of disease activity, less frequent flare, and a longer time to flare than patients receiving placebo. Treatment with etanercept was generally well-tolerated. CONCLUSIONS: Etanercept represents an exciting new therapeutic option for the treatment of JRA. The positioning of etanercept among other therapeutic options for JRA will be more clearly established as additional safety and efficacy data are made available.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

Clinical features of soft tissue sarcomas.

The presenting features of 526 patients referred to an open access 'lumps and bumps' clinic were reviewed to try and identify whether the four cardinal features of soft tissue malignancy were in fact predictive of this. The features investigated were: size bigger than 5 cm, pain, increase in size, depth beneath the deep fascia. All of these factors were found to be associated more frequently with malignancy than a benign state. Using the summed weights of evidence method we have constructed a graph which will allow prediction of whether a lump is likely to be malignant or not.

Adult↗
PubMed2000

Transesophageal echocardiographic findings in subcortical and cortical stroke.

Historically, subcortical stroke is believed to be secondary to intracranial small vessel disease. In this study, transesophageal echocardiographic findings such as aortic atherosclerotic disease and other potential cardiac sources of emboli were common in patients with subcortical stroke, supporting a multifactorial etiology for subcortical stroke and a role for transesophageal echocardiography in this patient population.

Aged↗
PubMed2000

Lipoprotein (a) and the risk of ischemic stroke in young women.

BACKGROUND AND PURPOSE: lipoprotein (a) (lp (a)) is a lipid-containing particle similar to LDL which has been found in atherosclerotic plaque. The role of lp (a) in ischemic stroke remains controversial, but some studies suggest lp (a) is particularly important as a risk factor for stroke in young adults. We investigated the role of lp (a) as a risk factor for stroke in young women enrolled in the Stroke Prevention in Young Women Study. METHODS: subjects were participants in a population-based, case-control study of risk factors for ischemic stroke in young women. Cases were derived from surveillance of 59 regional hospitals in the central Maryland, Washington DC, Pennsylvania and Delaware area. Lp (a) was measured in 110 cases and 216 age-matched controls. Demographics, risk factors, and stroke subtype were determined by interview and review of medical records. RESULTS: lp (a) values were higher in blacks than whites, but within racial groups, the distribution of lp (a) values was similar between cases and controls. After adjustment for age, race, hypertension, diabetes, cigarette smoking, coronary artery disease, total cholesterol and HDL cholesterol, the odds ratio for an association of lp (a) and stroke was 1.36 (95% CI 0.80-2.29). There was no dose-response relationship between lp (a) quintile and stroke risk. Among stroke subtypes, only lacunar stroke patients had significantly elevated lp (a) values compared to controls. CONCLUSIONS: we found no association of lp (a) with stroke in a population of young women with ischemic stroke. Small numbers of patients limit conclusions regarding risk in ischemic stroke subtypes, but we could not confirm previous suggestions of an association of lp (a) with atherosclerotic stroke in young adults.

Adolescent↗
PubMed2000

Expedition health and safety: a risk assessment.

Little has been published on the risks of participating in an expedition. A questionnaire survey was conducted to quantify those risks and to determine how expedition organizers plan for medical mishaps. 246 expeditions, taking 2381 participants to more than one hundred countries, were studied retrospectively. 65 expeditions (26%) reported no medical incidents; the remaining 181 reported 835 in 130,000 man-days (6.4 per 1000 man-days). 59% of the medical incidents seen on expeditions were preventable, one-third of these being due to gastrointestinal upsets. 78% of medical incidents were classified as minor and only 5% (40) as serious. There was no excess of serious incidents in any particular organizational group or environment. The findings of this survey suggest that the health risks of participating in a well-planned expedition are similar to those encountered during normal active life.

Adolescent↗
PubMed1999

Household firearm storage practices: do responses differ by whether or not individuals ever use firearms?

INTRODUCTION: The prevalence with which firearms are stored loaded or unlocked has been measured in previous surveys. Our purpose was to compare household firearm storage practices reported by firearm users and nonusers. METHODS: We analyzed telephone survey data from the 1992 and 1993 Oregon Behavioral Risk Factor Surveillance System on 2454 randomly selected adults in households with firearms. We compared reported firearm storage practices among persons who ever used firearms with persons who had never used firearms by demographics and type of firearm. RESULTS: Nonusers of firearms were much less likely than firearm users to report that household firearms were always or sometimes stored loaded [odds ratio (OR) = 0.45, 95% confidence interval (CI):0.36-0.54] or stored loaded and unlocked (OR = 0.46, 95% CI: 0.36-0.57). Except for persons aged 18 to 34 years and persons in handgun-only households, differences in reported firearm storage practices between nonusers and users varied little by demographic characteristics or by type of firearm. Nonusers of household firearms may be unaware that firearms are stored loaded or stored loaded and unlocked in their homes. CONCLUSIONS: Surveys that do not consider firearm use status may underestimate household exposure to loaded firearms or to loaded and unlocked firearms.

Accidents, Home↗
PubMed1999

Distribution and correlates of elevated total homocyst(e)ine: the Stroke Prevention in Young Women Study.

PURPOSE: To determine the distribution and correlates of elevated total homocyst(e)ine (tHcy) concentration in a population of premenopausal black and white women. METHODS: Data from the Stroke Prevention in Young Women Study (N = 304), a population-based study of risk factors for stroke in women aged 15-44 years of age, were used to determine the distribution and correlates of elevated tHcy in black (N = 103) and white women (N = 201). RESULTS: The mean tHcy level for the population was 6.58 micromol/L (range 2.89-26.5 micromol/L). Mean tHcy levels increased with age, cholesterol level, alcohol intake, and number of cigarettes smoked (all: p < 0.05). There were no race differences (mean tHcy 6.72 micromol/L among blacks and 6.51 micromol/L among whites; p = 0.4346). Regular use of multivitamins and increasing education was associated with significant reductions in tHcy concentration. Approximately 13% of the sample had elevated tHcy levels, defined as a tHcy concentration > or = 10.0 micromol/L. Multivariate-adjusted correlates of elevated tHcy included education > 12 vs. < or = 12 (odds ratio [OR] = 0.4, 95% confidence interval [CI] = 0.2-0.8); smoking > or = 20 cigarettes/day vs. nonsmokers (OR = 2.8, 95% CI = 1.1-7.3); and the regular use of multivitamins (OR = 0.4, 95% CI = 0.2-0.9). CONCLUSIONS: These results suggest that a substantial proportion of healthy young premenopausal women have tHcy levels that increase their risk for vascular disease. A number of potentially modifiable behavioral and environmental factors appear to be significantly related to elevated tHcy levels in young women.

Adolescent↗
PubMed1999

Fourteen-year follow-up of children with and without speech/language impairments: speech/language stability and outcomes.

This report concerns the speech and language outcomes of young adults (N = 242) who participated in a 14-year, prospective, longitudinal study of a community sample of children with (n = 114) and without (n = 128) speech and/or language impairments. Participants were initially identified at age 5 and subsequently followed at ages 12 and 19. Direct assessments were conducted in multiple domains (communicative, cognitive, academic, behavioral, and psychiatric) at all three time periods. Major findings included (a) high rates of continued communication difficulties in those with a history of impairment; (b) considerable stability in language performance over time; (c) better long-term outcomes for those with initial speech impairments than for those with language impairments; and (d) more favorable prognoses for those with specific language impairments than for those with impairments secondary to sensory, structural, neurological, or cognitive deficits. These general conclusions held when either a liberal or a more stringent criterion for language impairment was employed. Some of these findings are consistent with those from earlier follow-up studies, which used less optimal methods. Thus, the present replication and extension of these findings with a sound methodology enables greater confidence in their use for prognostic, planning, and research purposes.

Adolescent↗
PubMed1999

Local norming of the test of adolescent/adult language-3 in the Ottawa Speech and Language Study.

The young adult norms for the Test of Adolescent/Adult Language-3 (TOAL-3; D. Hammill et al., 1994) are based only on individuals who pursued postsecondary education, a restriction that renders the norms inappropriate for many clinical and research purposes. This research note details the rationale, methods, and results of a local norming of the TOAL-3 spoken language subtests, based on participants from the Ottawa Speech and Language Study (C. J. Johnson et al., 1999). The resulting Ottawa norms represent the full range of young adult language abilities and, therefore, can be used with caution for some clinical and research purposes.

Adolescent↗