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Biomedical subjects

C Cox

Publications and source records attributed to C Cox.

At least 181 records · Page 10Linked to original sources
PubMed1997

Ozone responsiveness in smokers and nonsmokers.

Short-term exposure to ozone causes decrements in lung function, but predictors of responsiveness remain largely unknown. Ninety healthy volunteers (56 never-smokers, age [mean +/- SD] 25 +/- 4 yr; 34 current smokers, 13 +/- 9 pack-yr, age 28 +/- 1 yr) were exposed to 0.22 ppm ozone for 4 h, with exercise, in an environmental chamber. We measured spirometry and specific airway conductance before, during, and immediately after exposure, and assessed symptoms by questionnaire. Smokers experienced a smaller increase in respiratory symptoms following exposure to ozone than did nonsmokers. Decrements in FEV1 were significantly less than for smokers than for nonsmokers (p = 0.0013). Ozone responsiveness (> 15% fall in FEV1) occurred in 16 of 56 never-smokers (28.6%) and 4 of 34 smokers (11.8%). Multiple logistic regression analysis found pack-yr of smoking to be associated with decreased ozone responsiveness (odds ratio [OR] 0.87, p = 0.017). Age, gender, and methacholine responsiveness were not predictive of responder status. Fourteen smokers and 25 nonsmokers were subsequently exposed once to air and twice to ozone; smokers as well as nonsmokers were consistent in their subsequent responsiveness (or lack of responsiveness) to ozone. Healthy smokers have smaller decrements in lung function and fewer symptoms in response to ozone exposure than do nonsmokers.

Adolescent↗
PubMed1997

Airway inflammation in smokers and nonsmokers with varying responsiveness to ozone.

Exposure to ozone causes symptoms, changes in lung function, and airway inflammation. We studied whether individuals who differ in lung-function responsiveness to ozone, or in smoking status, also differ in susceptibility to airway inflammation. Healthy subjects were selected on the basis of responsiveness to a classifying exposure to 0.22 ppm ozone for 4 h with exercise (responders, with a decrease in FEV1 > 15%; and non-responders, with a decrease in FEV1 < 5%). Three groups were studied: nonsmoker-nonresponders (n = 12), nonsmoker-responders (n = 13), and smokers (n = 13, 11 nonresponders and two responders). Each subject underwent two exposures to ozone and one to air, separated by at least 3 wk; bronchoalveolar and nasal lavages were performed on three occasions: immediately (early) and 18 h (late) after ozone exposure, and either early or late after air exposure. Recovery of polymorphonuclear leukocytes (PMN) increased progressively in all groups, and by up to 6-fold late after ozone exposure. Interleukin-6 (IL-6) and IL-8 increased early (by up to 10-fold and up to 2-fold, respectively), and correlated with the late increase in PMN. Lymphocytes, mast cells, and eosinophils also increased late after exposure. We conclude that ozone-induced airway inflammation is independent of smoking status or airway responsiveness to ozone.

Adolescent↗
PubMed1997

The Role of Selective Lymphadenectomy in Breast Cancer.

BACKGROUND: Axillary node dissection is considered a standard staging procedure in patients with breast cancer. The procedure is associated with significant morbidity and provides pathologists with many lymph nodes to evaluate. METHODS: A total of 174 women participated in a trial that included preoperative lymphoscintigraphy and intraoperative lymphatic mapping using a combination of a vital blue dye and radiocolloid mapping. RESULTS: The intraoperative lymphatic mapping correctly identified a sentinel lymph node (SLN) in 160 (92%) of 174 patients. One skip metastasis (0.7%) occurred in 136 women who had a subsequent complete node dissection. CONCLUSIONS: Lymphatic mapping and SLN biopsy using a combination of mapping techniques provide accurate nodal staging for women with breast cancer. With this technique, approximately 70% to 80% of women with no axillary metastases could be spared the morbidity of a complete node dissection.

Journal Article↗
PubMed1997

Menopausal Status and the Impact of Early Recurrence on Breast Cancer Survival.

BACKGROUND: Breast cancer represents the leading form of invasive cancer among American women, killing nearly 50,000 annually. Several prognostic factors that are associated with survival include age, race, menopausal status, and the stage of disease at presentation. METHODS: Patient characteristics were collected based on a systematic chart audit of demographic features and medical, family, and social histories. We studied the survival of 220 patients with recurrent disease out of 1,429 consecutive patients with breast cancer seen over a 15-year period. RESULTS: Patients with a disease-free interval following diagnosis of less than 24 months were more frequently premenopausal and hormone receptor-negative than those with a disease-free interval of 24 months or greater. Patients with early recurrence had a shorter survival than patients with late recurrence. Menopausal status, nodal involvement, receptor status, and the site of recurrent disease were independent predictors of survival following recurrence. CONCLUSIONS: Premenopausal women with early recurrence of breast cancer experience a significantly shorter survival than those with late recurrence, even after adjustment for hormone receptor status and site of recurrence. This effect was not seen in postmenopausal women.

Journal Article↗
PubMed1997

Long-term care: a comparison of policies and services in Israel and the United Kingdom and implications for the United States.

The issue of long-term care continues to be a main concern in the United States. As the country wrestles with the development of policies and services, the experiences of Israel, whose system rests upon national insurance, and that of the United Kingdom, which is based on grants to local authorities, can act as valuable teaching aids in the development of programs in the United States. Although both countries focus on community care with virtually universal access, concern over resources is forcing each to target their services increasingly to the most frail. The findings underscore the necessity for accurate planning and adequate resources if services are to meet the needs of the frail elderly population.

Aged↗
PubMed1997

Pulmonary administration of gentamicin during liquid ventilation in a newborn lamb lung injury model.

OBJECTIVES: Newborns with pulmonary infection frequently present with acute lung injury leading to ventilation/perfusion abnormalities in which intravenous delivery of antibiotics to the lung can be suboptimal. Tidal liquid ventilation (TLV) has been shown to be an effective means for delivering drugs directly to the pulmonary system. The objective of this study was to compare, with lung injury, antibiotic delivery achieved by conventional techniques (gas ventilation and intravenous gentamicin) with that using pulmonary administration of drug (PAD) during TLV. METHODS: Twelve newborn lambs with an acid lung injury were randomized to receive gentamicin either intravenously during gas ventilation or via PAD during TLV using LiquiVent (Alliance Pharmaceutical Corporation, San Diego, CA, and Hoechst-Marion Roussel, Bridgewater, NJ) perfluorochemical. Gentamicin (5 mg/kg) was administered over 1 minute, and serum levels were obtained at 15-minute intervals. Arterial blood gases and pulmonary mechanics were measured. Ventilation efficiency index and arterial/alveolar oxygen ratio were calculated. Lung-tissue gentamicin levels were measured 4 hours after administration and corrected to dry weight. RESULTS: Serum gentamicin levels were similar in both groups. Lung gentamicin levels (micrograms/g) were significantly higher for TLV. Also, TLV resulted in significantly more of the total delivered dose in the lung after 4 hours. Ventilation efficiency index and arterial/alveolar oxygen ratios were significantly higher for TLV. CONCLUSIONS: In this lung injury model, both methods achieved equivalent serum gentamicin levels with higher lung levels using PAD during TLV. This study suggests that TLV may provide an effective vehicle for gentamicin delivery in infants with severe pulmonary infection and ventilation/perfusion abnormalities.

Animals↗
PubMed1997

Suicide and alcoholism. Distinguishing alcoholic patients with and without comorbid drug abuse.

Psychological autopsy data were used to test the hypothesis that alcoholic patients with comorbid drug use disorders who committed suicide (A + D; n = 26) are distinguishable from alcoholic suicide victims without a comorbid drug use disorder (A; n = 35). Dependent variables included demographics, suicidal behavior; psychiatric symptoms, and medical illness burden. The A group were older, white, and tended to be living alone. Analyses that controlled for age and sex indicated that As were more likely to have had a comorbid major depression and less likely to tell someone they were contemplating suicide. Scores on a measure of illness burden increased with age among the A group but not the A + D group, though the latter were more likely to be under a physician's care with increasing age. These differences should be considered when designing preventive measures.

Adult↗
PubMed1997

Screening Childhood Cancer Survivors for Breast Cancer.

The development of second primary solid tumors, especially breast neoplasms, is increased among patients who have survived childhood or adolescent malignancies. With the increased long-term survival of patients with pediatric cancer, questions regarding breast cancer screening in this group have been raised. At this time, there are no established guidelines for breast cancer surveillance in this high-risk population. The objective of this review is to summarize the incidence, list additional risk factors for the development of breast cancer, and discuss the benefits of early detection of second primary breast cancers in pediatric cancer survivors. We have devised an algorithm for breast cancer screening in survivors of childhood malignancy. Implications of treatment with radiation and chemotherapy and the influence on prognosis of genetic abnormalities such as p53 mutations are debated.

Journal Article↗
PubMed1997

Perinatal methanol exposure in the rat. II. Behavioral effects in neonates and adults.

The use of methanol as a component of automobile fuel will increase perinatal exposures in the general population. Few studies have addressed questions concerning neurotoxicity stemming from such exposures. In the current study, four cohorts of pregnant Long-Evans rats, each cohort consisting of an exposure and a control group, were exposed to 4500 ppm methanol vapor in Rochester-type inhalation chambers for 6 hr daily beginning on Gestation Day 6. Exposure continued for both dams and pups through Postnatal Day 21 (PND 21) to model gestational and neonatal toxicity in humans. Several behavioral procedures were used to assess exposure effects in the offspring. Male-female littermates were studied whenever possible to examine sex differences, with one pair from a litter for each procedure. Exposure to methanol did not affect suckling latency and nipple attachment on PND 5 or performance on an aversive olfactory conditioning procedure on PND 10. Exposure to methanol did alter performances in a motor activity procedure. Methanol-exposed neonates were less active on PND 18, but more active on PND 25 than the equivalent control group pups. Two operant conditioning procedures, not used previously in this context, assayed other littermates as adults. A fixed ratio schedule required the rat to rotate a running wheel a specified number of revolutions to obtain food-pellet reinforcers. When the fixed ratio requirement changed, number of responses (revolutions) per 1-hr session displayed a complex interaction with treatment. Changes in performance over the course of training differed between males and females depending on exposure to methanol. Compared to initial baseline performances, methanol-exposed males showed decreases, and methanol-exposed females increases, in the rate of running. A stochastic spatial discrimination procedure permitted subjects to respond on any three levers, with the probabilities of food-pellet delivery determined by the location of the preceding response. A reinforcement matrix defined the response sequence required to maximize reinforcements. When the matrix was changed, the methanol-exposed subjects responded less efficiently at asymptotic levels of performance than controls. Across procedures, developmental exposure to 4500 ppm methanol vapor was associated with subtle behavioral changes in both neonates and adults.

Administration, Inhalation↗
PubMed1997

Effects of prenatal methylmercury exposure from a high fish diet on developmental milestones in the Seychelles Child Development Study.

Mercury is widespread in the environment and exists in several physical and chemical forms. Prenatal exposure to methylmercury disrupts brain development. The most common mode of prenatal methylmercury exposure is maternal fish consumption. Studies of human prenatal exposure in Iraq following maternal ingestion of methylmercury treated grain suggested that maternal hair mercury concentrations above 10 ppm may be related to delayed developmental milestones and neurological abnormalities. This level of exposure can be achieved by frequent consumption of fish. The Seychelles Child Development Study analyzed developmental milestones similar to those determined in Iraq in a large controlled, prospective study of children exposed prenatally to methylmercury when their mothers ate fish. As part of this ongoing study, cohort children were evaluated at 6.5, 19, 29, and 66 months of age. At 19 months care-givers were asked at what age the child walked (n=720 out of 738) and talked (n=680). Prenatal mercury exposure was determined by atomic absorption analysis of maternal hair segments corresponding to hair growth during the pregnancy. The median mercury level in maternal hair was 5.8 ppm with a range of 0.5-26.7 ppm. The mean age (in months) at walking was 10.7 (SD = 1.9) for females and 10.6 (SD = 2.0) for males. The mean age at talking (in months) was 10.5 (SD = 2.6) for females, and 11.0 (SD = 2.9) for males. After adjusting for covariates and statistical outliers, no association was found between the age at which Seychellois children walked or talked and prenatal exposure to mercury. Normal ages at achievement of the developmental milestones walking and talking were found in Seychellois toddlers following prenatal exposure to methylmercury from a maternal fish diet. These results do not support the lowest effect levels in young children following prenatal methylmercury exposure predicted by the dose response analysis of the Iraq data. More detailed studies in older children are needed to determine if there are adverse effects in fish eating populations.

Animals↗
PubMed1997

Effects of ozone on normal and potentially sensitive human subjects. Part II: Airway inflammation and responsiveness to ozone in nonsmokers and smokers.

Exposure to ozone at levels near the National Ambient Air Quality Standard causes respiratory symptoms, changes in lung function, and airway inflammation. Although ozone-induced changes in lung function have been well characterized in healthy individuals, the relationship between airway inflammation and changes in pulmonary function have not been prospectively examined. The purpose of this study was to determine whether individuals who differ in, lung function responsiveness to ozone also differ in susceptibility to airway inflammation and injury. A secondary goal was to determine whether ozone exposure induces airway inflammation in smokers, a population known to have airway inflammation and an increased burden of toxic oxygen species. Healthy nonsmokers (n = 56) and smokers (n = 34) were exposed to 0.22 parts per million (ppm)* ozone for 4 hours, with intermittent exercise, for the purpose of selecting ozone "responders" (decrement in forced expiratory volume in 1 second [FEV1] > 15%) and "nonresponders" (decrement in FEV1 < 5%). Selected subjects then were exposed twice to ozone (0.22 ppm for 4 hours with exercise) and once to air (with the same exposure protocol), each pair of exposures separated by at least 3 weeks, in a randomized, double-blind fashion. Nasal lavage (NL) and bronchoalveolar lavage (BAL) were performed immediately after one ozone exposure and 18 hours after the other, and either immediately or 18 hours after the air exposure. Indicators of airway effects in lavage fluid included changes in inflammatory cells, proinflammatory cytokines, protein markers of epithelial injury and repair, and generation of toxic oxygen species. In the classification exposure, fewer smokers than nonsmokers were responsive to ozone (11.8% vs. 28.6%, respectively); an insufficient number of smoker-responders were identified to study as a separate group. In the BAL study, all groups developed a similar degree of airway inflammation, consisting of increases in interleukins 6 and 8 (maximal immediately after exposure), and increases in polymorphonuclear leukocytes (PMNs), lymphocytes, and mast cells (maximal 18 hours after exposure). The increase in PMNs was inversely correlated with age (p = 0.013), but gender, nonspecific airway responsiveness, and allergy history were not predictive of inflammation. Alveolar macrophage production of toxic oxygen species decreased after ozone exposure in nonsmokers; however, not in smokers. Findings from nasal lavage did not mirror lower airway inflammatory responses in these studies. We conclude that, in response to ozone exposure, smokers experienced smaller decrements in lung function and fewer symptoms than nonsmokers; however, the intensity of the airway inflammatory response was independent of smoking status or airway responsiveness to ozone. Furthermore, the burden of toxic oxygen species following ozone exposure was greater for smokers than for nonsmokers. Subjects were young, healthy, and able to sustain exercise; the results may not be representative of nonsmokers or smokers in general. Nevertheless, the findings indicate that measuring symptoms and spirometric changes is not sufficient to assess the potential risks associated with ozone exposure.

Adolescent↗
PubMed1997

Effects of ozone on normal and potentially sensitive human subjects. Part III: Mediators of inflammation in bronchoalveolar lavage fluid from nonsmokers, smokers, and asthmatic subjects exposed to ozone: a collaborative study.

To provide bases of comparison between the studies described in Parts I and II of this Research Report, concentrations of interleukin 6 (IL-6)*, interleukin 8 (IL-8), and alpha 2-macroglobulin (a2M) were measured in airway lavage fluids obtained in the Balmes study (Part I) and compared with the same measurements in the Frampton study (Part II). For healthy subjects in the Balmes study, IL-6 and a2M, but not IL-8, increased in association with ozone exposure. Statistical analyses suggested that effects of ozone on IL-8 levels observed in the first exposure and bronchoscopy may have carried over to the second exposure and bronchoscopy, which may have obscured an effect of ozone on IL-8 after the second exposure. For asthmatic subjects in the Balmes study, IL-6 and IL-8 increased in both bronchial and alveolar lavage fluid, but not in proximal airway lavage fluid. The mean interval between exposures was longer for asthmatic subjects than for healthy subjects, and no carryover effects were seen. When the Balmes and Frampton data were analyzed together, subject groups in the two studies (nonsmokers, smokers, and subjects without and with asthma) did not differ significantly in the response of cytokines to ozone exposure. The finding of possible carryover effects in one group suggests that subtle effects of ozone exposure, or bronchoscopy including proximal airway lavage and biopsy, or both, may persist for three weeks in some subjects.

Adolescent↗
PubMed1997

Case management: an American's observations of community care in Britain.

The United States faces a rapidly growing aging population, government reforms, and policy shifts to give primary responsibility to the states for programs of community-based care for the elderly. At the same time, increasing concern is being given to the more effective use of home and community-based services, and particularly what role case management might play. Given these changes, much may be learned from the 1993 reforms to the British system of community care, which made case management the cornerstone of the system and gave primary responsibility for community care programs to local social service departments. This examination of the programs in Britain, conducted largely through site visits and personal interviews with social service staff, describes the successes and shortcomings of the implementation of the community care reforms with recommendations for program development in the United States.

Case Management↗
PubMed1996

Chronic treatment with typical and atypical antipsychotics increases the AMPA-preferring form of AMPA receptor in rat brain.

We assessed the effects of chronic (21 day) administration of antipsychotic drugs on the density of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor in rat brain. We used two typical antipsychotic drugs, haloperidol and pimozide, and two atypical antipsychotic drugs, risperidone and clozapine. Antipsychotic drugs as a group significantly elevated the density of the AMPA receptor measured with an AMPA receptor agonist ([3H]AMPA), but not with an AMPA receptor antagonist, 6-cyano-7-nitro-quinoxaline-2,3-dione ([3H]CNQX). In all regions studied, the magnitude of the increase seen with chronic typical antipsychotic drugs was significantly greater than that seen with chronic atypical antipsychotic drugs. In frontal cortex and striatum, typical antipsychotics but not atypical antipsychotics elevated AMPA receptor binding over control. These findings suggest that antipsychotic drugs alter the agonist affinity of the AMPA receptor without altering the number of AMPA receptors. Typical antipsychotic drugs may be more potent in this effect than atypical antipsychotic drugs, especially in critical corticostriatal circuits.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1996

Lymphatic mapping and sentinel node biopsy in the patient with breast cancer.

OBJECTIVES: To identify the sentinel lymph node(s) (SLN[s]) (the first node[s] draining the primary tumor in the regional lymphatic basin) in patients with invasive breast cancer and to test the hypothesis that the histologic characteristics of the SLN predict the histologic characteristics of the remaining lymph nodes in the axilla. DESIGN: A prospective trial. PARTICIPANTS: Sixty-two patients with newly diagnosed invasive breast cancers. INTERVENTION: Patients underwent intraoperative lymphatic mapping using a combination of a vital blue dye and filtered technetium-labeled sulfur colloid. The SLN was identified and removed, followed by a definitive cancer operation, including a complete axillary node dissection. MAIN OUTCOME MEASURE: The metastatic distribution in the axilla was determined in patients with occult nodal disease. RESULTS: The SLN was successfully identified in 57 (92%) of 62 patients using the 2 lymphatic mapping procedures. After localization, 18 patients (32%) were found to have metastatic disease, and the SLN tested positive in all 18 patients. There were no "skip" metastases, defined as an SLN that tested negative with higher nodes that tested positive. In 12 (67%) of 18 patients with metastatic disease, the SLN was the only site of disease. The metastatic distribution significantly favored SLN involvement. Among subjects with discordant nodal involvement, the probability of observing the distribution of SLN involvement by chance is very small (P<.001). CONCLUSIONS: This study confirms that lymphatic mapping is technically possible in the patient with breast cancer and that the histologic characteristics of the SLN probably reflect the histologic characteristics of the rest of the axillary lymph nodes. The procedure also allows the pathologist to focus the histologic examination on 1 or 2 nodes, potentially increasing the yield of positive dissections and the accuracy of staging.

Axilla↗