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Biomedical subjects

B E Richardson

Publications and source records attributed to B E Richardson.

12 recordsLinked to original sources
PubMed2001

Postintubation phonatory insufficiency: an elusive diagnosis.

OBJECTIVE: To describe postintubation phonatory insufficiency, a routinely overlooked complication of prolonged intubation. This entity results from an erosive injury with permanent divots of the medial surfaces of the arytenoid cartilages and/or scarring of the anterior cricoarytenoid joint capsule so that during phonation there is incomplete adduction and a glottic gap remains. SETTING: Tertiary care center. STUDY DESIGN/RESULTS: We present a retrospective review of the findings of 138 patients evaluated for chronic intubation injuries in our voice laboratory using a diagnostic model composed of pertinent history, elicited vocal capabilities and limitations, and an intense fiberoptic laryngeal examination directed at revealing the suspected injuries. CONCLUSION/SIGNIFICANCE: In many patients, the diagnosis of postintubation phonatory insufficiency was made years after the intubation injury occurred and after numerous nondiagnostic examinations elsewhere. Mechanisms of intubation injury are reviewed, and prevention and treatment of the condition are discussed.

Female↗
PubMed2000

Mean arterial pressure, pregnancy-induced hypertension, and preeclampsia: evaluation as independent risk factors and as surrogates for high maternal serum alpha-fetoprotein in estimating breast cancer risk.

Data from a nested case-control study were analyzed to examine high mean arterial pressure (MAP), hypertension of pregnancy, and preeclampsia as independent predictors and as surrogate markers for elevated alpha-fetoprotein (AFP) levels in evaluating breast cancer risk. Cases (n = 205) were identified by the California Cancer Registry from a cohort of pregnant women who were part of the Kaiser Health Plan and took part in the Child Health and Development Studies initiated by the University of California, Berkeley, from June 1959 to September 1966. Controls (n = 337) were selected by randomized recruitment from the same cohort probability matched to cases by distribution of birth dates of cases. High MAP was associated with breast cancer risk and is different across quartile of age at first full-term pregnancy as is high AFP. Odds ratios (OR) across quartiles for MAP were 0.24 [95% confidence interval (CI), 0.08-0.71], 0.84 (95% CI, 0.39-1.66), 1.00 (referent), and 2.50 (95% CI, 1.21-5.13), and for AFP were 0.34 (95% CI, 0.13-0.93), 0.77 (95% CI, 0.36-1.67), 1.00 (referent), and 2.38 (95% CI, 1.13-5.00). Neither diagnosed preeclampsia nor hypertension of pregnancy showed any association with breast cancer risk. When both high AFP and high MAP were entered into the same analysis, neither changed the OR for the other more than 8%. Additionally, AFP level was not a linear function of MAP. Although the pattern of ORs across quartiles of age at first full-term pregnancy was similar for the two variables, it cannot be concluded that high MAP is an adequate surrogate for high levels of maternal serum AFP, but rather represents some related process that is in and of itself a risk factor for breast cancer.

Adolescent↗
PubMed1998

Levels of maternal serum alpha-fetoprotein (AFP) in pregnant women and subsequent breast cancer risk.

High maternal serum alpha-fetoprotein (AFP) levels during pregnancy may be instrumental in reducing the subsequent risk of breast cancer. This hypothesis was tested in a nested case-control study using stored frozen sera accrued between 1959 and 1966 by the University of California at Berkeley Child Health and Development Studies (CHDS) group from a cohort of pregnant women. Cases with histologically confirmed breast cancer were identified from California Cancer Registry files covering their date of enrollment in the CHDS until 1994. Controls were selected from the CHDS cohort by using randomized recruitment. Third-trimester maternal serum AFP levels were analyzed by using both a radioimmunoassay and an immunoenzymatic method. After controlling for multiple confounders in logistic regression models, the authors found an inverse association between high levels of maternal serum AFP (top quartile) during the index pregnancy and the risk of breast cancer. The protective effect of high levels of maternal serum AFP varied by age at first full-term pregnancy (age 20 years or less: odds ratio (OR) = 0.43, 95% confidence interval (CI) 0.28-0.65; age 21-23 years: OR = 0.62, 95% CI 0.41-0.92). After age 27 years, the estimated risk exceeded unity (OR = 1.67, 95% CI 1.14-2.45). These study findings suggest that some of the protection against breast cancer conferred by early first full-term pregnancy may result from high levels of maternal serum AFP. After age 27 years, a high maternal serum AFP level is not protective and may increase risk.

Adolescent↗
PubMed1998

Videoendoscopic swallowing study for diagnosis of Zenker's diverticuli.

The videoendoscopic swallowing study (VESS) provides an efficient, cost-effective method for swallowing evaluation in the clinic. Previously thought to be of little value for disorders of the proximal esophagus, this retrospective study (n = 33) demonstrates a high level of sensitivity (85%) and specificity (86%) of VESS for detecting Zenker's diverticuli in patients with symptoms of swallowing dysfunction. Furthermore, the key finding of postswallow reflux into the hypopharynx reliably distinguishes cricopharyngeus dysfunction from diverticuli in this population. This study shows that VESS can provide useful information about the proximal esophagus.

Deglutition↗
PubMed1997

Effect of antagonism at central nervous system M3 muscarinic receptors on laryngeal chemoresponse.

The laryngeal chemoresponse (LCR), comprising laryngeal adductor spasm, central apnea, and subsequent cardiovascular instability, is thought to be a factor in sudden infant death syndrome. A muscarinic subtype receptor, M3, appears to be involved in central respiratory drive and control. Both the duration of the LCR apnea and levels of M3 receptor messenger RNA in the brain stem change according to postnatal age. This study examined the effect of central nervous system antagonism at M3 receptors on the LCR with respect to animal age and dose of antagonist. Ten piglets in each of three age groups (group 1, 5 to 8 days; group 2, 18 to 21 days; and group 3, 40 to 43 days) received a series of four increasing doses of an M3 antagonist (p-fluoro-hexahydro-sila-diphenidol) by intracerebral ventricle injection. The LCR was evoked at baseline and after each dose of antagonist. An effect on susceptible animals (groups 1 and 2) was evident by the second antagonist dose, and persisted for the remainder of the experiment (2 hours). At completion of the experiment, mean apnea duration had decreased in group 1 (61%, p < .05), and group 2 (57%, p < .05), but was unchanged in group 3 (<10%, p not significant). Length of mean baseline apneas correlated directly with degree of apnea shortening. The reduction is not attributable to changes in arterial PO2 or PCO2 or baseline respiratory rate. These results support an age-related influence on the LCR by M3 receptors in younger animals that decreases with maturation.

Age Factors↗
PubMed1995

A study of milk and calcium supplement intake and subsequent preeclampsia in a cohort of pregnant women.

To test the hypothesis that high calcium intake protects against preeclampsia, the relation between milk intake and preeclampsia was examined in a cohort of 9,291 pregnant women (7,104 white women and 2,187 black women) selected from the Child Health and Development Study population assembled by the University of California, Berkeley, during 1959-1966. Exposure was based on glasses of milk per day with and without calcium supplements. Data from both white and black women displayed a U-shaped distribution of preeclampsia risk in relation to milk and milk plus supplement intake. Logistic regression analysis showed that women who drank two glasses of milk per day had the lowest risk (reference category). The relative risk (RR) for those drinking one glass of milk per day was similarly low (RR = 1.2; 95 percent confidence interval (CI) 0.7-2.0), but risk for those drinking less than one glass of milk per day was substantially higher (RR = 1.9; 95 percent CI 1.2-2.9). Women drinking three or more glasses of milk per day also showed increased risk (RR = 2.0; 95 percent CI 1.2-3.4) as did those drinking four or more glasses per day (RR = 1.8; 95 percent CI 1.1-3.0). The increased risk associated with low milk intake is consistent with studies showing reduced blood pressure with increased calcium intake. The increased risk with high milk intake has not been demonstrated previously.

Adult↗
PubMed1990

Blood flow changes in chicken brain stem auditory nuclei following cochlea removal.

Cochlea removal results in rapid and persistent metabolic and morphological changes in avian brain stem auditory nuclei. Because such changes in the central nervous system are often associated with changes in local blood flow, we examined blood flow in second-order auditory nucleus magnocellularis (NM) and third-order nucleus laminaris (NL). The diffusible tracer [14C]-iodoantipyrine was infused intravenously into 20- to 26-day-old chickens either 30 min or 6 h after unilateral cochlea removal. This tracer rapidly equilibrates between blood and tissue in proportion to local blood flow. Unoperated animals served as controls. Thirty seconds after tracer infusion, brains were removed and frozen. Cryostat sections were prepared for quantitative film autoradiography. Blood flow in normal and deafferented areas within NM and NL was compared. Nucleus magnocellularis receives its only excitatory input from the ipsilateral cochlea via the eighth nerve. Axons from NM bifurcate and project to the ipsilateral dorsal dendritic region of NL (NLd) and the contralateral ventral dendritic region of NL (NLv). Thirty minutes after cochlea removal, blood flow in ipsilateral NM decreases by 30%. This decrease persists at 6 hours. Blood flow in NL does not change in accordance with the pattern of afferent input from NM. Rather, blood flow in NLd and NLv ipsilateral to cochlea removal is significantly decreased 6 h post lesion. These results are in contrast to the pattern of morphological and metabolic changes observed in NL after cochlea removal.

Animals↗
PubMed1990

Effect of dose of Brucella abortus strain 19 in yearling heifers on the relative risk of developing brucellosis from challenge exposure with strain 2308.

Yearling heifers were given SC injections of 10(8) (n = 40), 10(9) (n = 44), or 10(10) (n = 44) colony-forming units of Brucella abortus strain 19 (S19). The proportion of heifers with positive serologic test results at 1 month following vaccination increased as the dose of S19 increased. These proportions decreased with time, and all heifers had negative card, rivanol, and complement fixation test results within 4 months. Positive ELISA results persisted beyond 4 months in all three S19 dose groups; however, all heifers were ELISA-negative within 9 months after vaccination. Comparable lymphocyte transformation activity was stimulated by S19 dose of 10(9) or 10(10) and approximately half of the heifers in both groups had a positive stimulation index at 9 months. Immunity of the pregnant heifers was challenged 9 months after vaccination with 10(7) B abortus strain 2308 as follows: diluent controls (n = 69); 10(8) B abortus S19 (n = 40); 10(9) B abortus S19 (n = 39); and 10(10) B abortus S19 (n = 39). Tissue specimens from heifers were obtained at parturition and necropsy for culturing of B abortus. The proportion of heifers that developed brucellosis, ie, had positive culture results, increased as gestation days at challenge exposure increased. The effect of gestational age was controlled in the analysis using logistic regression. The relative risk of brucellosis was reduced to 0.38, 0.15, and 0.06 for B abortus S19 doses of 10(8), 10(9), and 10(10), respectively, compared with diluent controls at 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1989

Experimental infection of dogs with Brucella abortus: effect of exposure dose on serologic responses and comparison of culture methods.

Two studies of experimentally induced Brucella abortus infections in dogs are reported. Twenty dogs in experiment 1 were fed approximately 4.8 X 10(10) colony forming units of B. abortus strain 2308 (BA 2308), and 11 dogs in experiment 2 were fed approximately 3.4 X 10(14) BA 2308. Serum samples from each infected dog and noninfected control were tested on the day of infection and at weekly and biweekly intervals post-infection (PI) for antibodies to B. abortus. The standard tube agglutination (STA) and rivanol (RIV) mean log-titers of the infected dogs in the 2 experiments were compared statistically on the day of infection and on PI days 7, 14, 21, 35, 42 and 49. The STA and RIV titers of the infected dogs in experiment 2 were significantly higher than were those of the dogs in experiment 1. Brucella abortus was isolated from 29 infected dogs in experiments 1 and 2 including 10 dogs, which were seronegative when cultured.

Animals↗
PubMed1988

Correlation of field strain exposure with new cases of brucellosis in six beef herds vaccinated with strain 19.

Three hundred sixty cattle at risk in 6 beef herds known to include cows infected with Brucella abortus field strains were vaccinated with 3 x 10(9) colony-forming units of strain 19. Field strain exposure after vaccination was estimated by the number of cows with brucellosis that calved or aborted in the herd. As the number of exposures increased, the number of cows developing brucellosis increased, and 19 exposures in the 6 herds resulted in 9 new cases. The ratio of exposures to new cases varied from 1.0 to 2.0 in the 4 herds with new cases, whereas 2 herds with 1 and 3 exposures, respectively, did not have new cases of brucellosis. The correlation coefficient between the number of exposures and the number of new cases was 0.85, and the coefficient of determination suggested that 73% of the variation in new cases could be explained by the number of exposures in strain 19-vaccinated herds.

Animals↗