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N Cobb

Publications and source records attributed to N Cobb.

At least 19 recordsLinked to original sources
PubMed2001

Zebrafish E-cadherin: expression during early embryogenesis and regulation during brain development.

Zebrafish E-cadherin (cdh1) cell adhesion molecule cDNAs were cloned. We investigated spatial and temporal expression of cdh1 during early embryogenesis. Expression was observed in blastomeres, the anterior mesoderm during gastrulation, and developing epithelial structures. In the developing nervous system, cdh1 was detected at the pharyngula stage (24 hpf) in the midbrain-hindbrain boundary (MHB). Developmental regulation of MHB formation involves wnt1 and pax2.1. wnt1 expression preceded cdh1 expression during MHB formation, and cdh1 expression in the MHB was dependent on normal development of this structure.

Animals↗
PubMed2001

Evaluating the value of screening for hypertension: an evidence-based approach.

No recommendations regarding in-school blood pressure (BP) screening currently exist. The purpose of this project was to use an evidence-based approach to determine whether BP screening should be initiated as part of one school district's standard screening protocols. Pediatric BP measurement, risk factors for hypertension, issues for determining youth at risk for hypertension, and eligibility criteria for determining conditions appropriate for screening are discussed. BPs of 1st, 6th, and 11th graders were evaluated according to standardized criteria. The evidence indicated that BP screening in school appears warranted, although a formalized study is needed before a definitive decision can be made regarding the incorporation of BP screening into school health services.

Adolescent↗
PubMed1999

R-cadherin expression in the developing and adult zebrafish visual system.

Cell adhesion molecules in the cadherin family have been implicated in histogenesis and maintenance of cellular structure and function in several organs. Zebrafish have emerged as an important new developmental model, but only three zebrafish cadherin molecules have been identified to date (N-cadherin, paraxial protocadherin, and VN-cadherin). We began a systematic study to identify other zebrafish cadherins by screening zebrafish cDNA libraries using an antibody raised to the cytoplasmic domain of mouse E-cadherin. Here, we report a partial cDNA with extensive sequence homology to R-cadherin. Spatial and temporal expression of this putative zebrafish R-cadherin was examined in embryos and adults by Northern analysis, RNase protection, and in situ hybridization. R-cadherin message increased during embryogenesis up to 80 hours postfertilization (hpf) and persisted in adults. In the embryonic brain, R-cadherin was first expressed in groups of cells in the diencephalon and pretectum. In adult zebrafish brain, R-cadherin continued to be expressed in several specific regions including primary visual targets. In the retina, R-cadherin was first detected at about 33 hours postfertilization in the retinal ganglion cell layer and the inner part of the inner nuclear layer. Expression levels were highest during periods of axon outgrowth and synaptogenesis. Retrograde labeling of the optic nerve with 1,1'-dioctadecyl-3,3,3',3', tetramethylindocarbocyanine perchlorate (DiI) followed by in situ hybridization confirmed that a subset of retinal ganglion cells in the embryo expressed R-cadherin message. In the adult, R-cadherin expression continued in a subpopulation of retinal ganglion cells. These results suggest that R-cadherin-mediated adhesion plays a role in development and maintenance of neuronal connections in zebrafish visual system.

Age Factors↗
PubMed1999

Cadherin function in junctional complex rearrangement and posttranslational control of cadherin expression.

The role of E-cadherin, a calcium-dependent adhesion protein, in organizing and maintaining epithelial junctions was examined in detail by expressing a fusion protein (GP2-Cad1) composed of the extracellular domain of a nonadherent glycoprotein (GP2) and the transmembrane and cytoplasmic domains of E-cadherin. All studies shown were also replicated using an analogous cell line that expresses a mutant cadherin construct (T151) under the control of tet repressor. Mutant cadherin was expressed at approximately 10% of the endogenous E-cadherin level and had no apparent effect on tight junction function or on distributions of adherens junction, tight junction, or desmosomal marker proteins in established Madin-Darby canine kidney cell monolayers. However, GP2-Cad1 accelerated the disassembly of epithelial junctional complexes and delayed their reassembly in calcium switch experiments. Inducing expression of GP2-Cad1 to levels approximately threefold greater than endogenous E-cadherin expression levels in control cells resulted in a decrease in endogenous E-cadherin levels. This was due in part to increased protein turnover, indicating a cellular mechanism for sensing and controlling E-cadherin levels. Cadherin association with catenins is necessary for strong cadherin-mediated cell-cell adhesion. In cells expressing low levels of GP2-Cad1, protein levels and stoichiometry of the endogenous cadherin-catenin complex were unaffected. Thus effects of GP2-Cad1 on epithelial junctional complex assembly and stability were not due to competition with endogenous E-cadherin for catenin binding. Rather, we suggest that GP2-Cad1 interferes with the packing of endogenous cadherin-catenin complexes into higher-order structures in junctional complexes that results in junction destabilization.

Amino Acid Sequence↗
PubMed1999

Improving cancer incidence estimates for American Indians in Minnesota.

OBJECTIVES: The purpose of this study was to estimate cancer incidence for American Indians in Minnesota. METHODS: Indian Health Service enrollment data were linked to the Minnesota tumor registry to identify cancers among American Indians in Minnesota. Incidence rates for the 5 most common cancers in this population, estimated after the linkage, were compared with rates estimated before the linkage and with rates for the total population of Minnesota. RESULTS: The linkage identified 302 cancer cases not previously identified as occurring among American Indians in Minnesota. Postlinkage estimates suggested that incidence rates for prostate and colorectal cancer are similar to those for the total population of Minnesota, but that rates of lung and cervical cancer are significantly higher. Breast cancer rates are slightly lower than those for the total population of Minnesota but more than twice as high as previous estimates for American Indians. CONCLUSIONS: The postlinkage estimates suggest different priorities for cancer education, prevention, and control than might be assumed from either prelinkage estimates or previously published data, and underscore the importance of using accurate and specific data for setting these priorities.

Female↗
PubMed1998

Patterns of cancer mortality among Native Americans.

BACKGROUND: Native Americans have been reported to have lower cancer incidence and mortality than other racial groups in the U.S., although some have questioned whether this was due to racial misclassification. This study provides improved estimates of cancer mortality, determined from a sampling of people who live on Indian reservations. METHODS: The authors reviewed death certificates from U.S. counties that contain Indian lands, excluding certain areas with known problems of racial misclassification. Age-adjusted mortality rates for specific types of cancer were calculated using U.S. Census population figures, and these rates were compared with rates for all races in the U.S. RESULTS: This sample included 38% of the American Indian and Alaska Native populations. The age-adjusted annual mortality rate for all cancers combined was 148.2 per 100,000 for both genders, 133.1 for females, and 167.2 for males. The rates for males and for both genders combined, but not for females, were significantly lower than the U.S. rates for all races (P < 0.05). Females had significantly lower rates of death from carcinoma of the lung and breast and significantly higher rates of death from carcinoma of the cervix and gallbladder (P < 0.05). Males had significantly lower rates of death from carcinoma of the lung, colon, and prostate, and significantly higher rates of liver carcinoma. Both genders combined had significantly lower rates of death from lung and colon carcinoma and significantly higher rates of death from stomach, liver, kidney, and gallbladder carcinoma. Geographic differences were substantial, with the Northern and Plains regions experiencing much higher mortality from lung, colon, and breast carcinoma than the Southwest region. CONCLUSIONS: Compared with the general U.S. population, Native Americans experience quite different patterns of cancer mortality. Cancer prevention and control programs should be designed specifically for this minority population.

Alaska↗
PubMed1998

Investigating cancer clusters.

A cluster is a mini-epidemic of a rare disease. Clusters may give clues to the etiology of disease, or may signal a hazardous exposure. Unfortunately, cluster investigations seldom are conclusive, for several reasons. Statistically significant clusters can occur by chance. The probability of finding chance cancer clusters is calculated for the 200 Alaska Native villages. The problem of selection bias is explained, and other limitations of epidemiology are described. A logical, stepwise protocol for investigating cancer clusters is presented.

Alaska↗
PubMed1996

Environmental causes of cancer among Native Americans.

Age-adjusted mortality from cancer is steadily increasing among Native Americans, raising concern about environmental causes. Toxic waste dumps, mining activities, paper mills, military activities, agricultural chemicals, and urban pollution are common sources of carcinogen exposure on reservations and among the urban poor. Despite documented hazards, we do not see a pattern of cancer excess that might result if Native Americans were exposed to these carcinogens more than other Americans. Abuse of tobacco can be shown to be the most important contributor to cancer mortality among Native Americans. Although there are good reasons for environmental regulation and clean-up, the most cost-effective method of cancer prevention is tobacco control.

Adult↗
PubMed1996

Urban-based Native American cancer-control activities: services and perceptions.

BACKGROUND: Cancer has become a significant health concern in American Indian communities. Over the past several decades Native peoples have experienced significant increases in life expectancy and, with these gains, significant increases in cancer incidence and mortality. Limited data are available concerning cancer-control activities accessible to American Indian communities. Even less is known about control programs in place for American Indians resident in urban areas, where more that half of all Native peoples reside. METHODS: To ascertain the extent of available services and perceptions of health directors, a survey of all Indian-Health-Service-recognized urban clinics was undertaken. RESULTS: Results indicate that the cancer needs of American Indians resident in urban areas are not being adequately addressed. Only one-third of urban health directors reported perceived increases in cancer incidence and mortality rates. The directors ranked cancer fifth among seven health problems in terms of their clinics' commitment to addressing them. Findings from this study are juxtaposed with whose obtained in a separate survey of reservation-based health directors. CONCLUSIONS: Results indicate a need to develop more responsive cancer-control programs in Indian country and to sensitize researchers to other health needs of these communities.

Cancer Care Facilities↗
PubMed1993

Black spots on the scalps of schoolchildren. A recurrent condition in the windy west.

During the past 10 years, epidemics of black spots on the scalps of schoolchildren have caused considerable concern in at least 4 communities in the Rocky Mountain states. We describe the clinical presentation of "black spots" in a group of Wyoming elementary school students and the epidemiologic investigation that revealed the cause. Our study included a questionnaire survey of students' parents, examination of students at the affected school and at two other schools, observation of playground activity patterns, and laboratory analysis of specimens taken from affected children and from the school environment. The black material in the scalp spots was chemically identical to flakes of black material found on the playground and tar from the school roof. We concluded that the spots were caused by flakes of windblown tar from the school roof. Previous outbreaks of black spots may have had a similar cause.

Air Pollutants↗
PubMed1991

Unintentional carbon monoxide-related deaths in the United States, 1979 through 1988.

OBJECTIVE: To describe the epidemiology of recent unintentional carbon monoxide poisoning deaths in the United States. DESIGN: Descriptive analysis of carbon monoxide-related deaths in the United States from 1979 through 1988, based on death certificate reports compiled by the National Center for Health Statistics. POPULATION STUDIED: All US deaths, 1979 through 1988. RESULTS: We reviewed data from 56,133 death certificates that contained codes implicating carbon monoxide as a contributing cause of death. Of these, 25,889 were suicides, 210 were homicides, 15,523 were associated with severe burns or house fires, and 11,547 were classified as unintentional. The number of unintentional deaths decreased steadily by about 63 deaths per year, from 1513 in 1979 to 878 in 1988. The highest death rates occurred in winter and among males, blacks, the elderly, and residents of northern states. Motor vehicle exhaust gas caused 6552 (57%) of the unintentional deaths; 5432 (83%) of these were associated with stationary automobiles. CONCLUSIONS: The rate of unintentional death from carbon monoxide poisoning is decreasing. This may be attributable to improvements in automobile pollution control systems and improved safety of cooking and heating appliances. Prevention programs should target young drivers, males, and the elderly.

Adolescent↗
PubMed1990

A new filter technique permitting traditional histopathological assessment of fine needle aspiration specimens.

We describe a new filtration method based on a transport medium technique which allows histopathological assessment of the tissue fragments present in many fine needle aspirates. Fine needle aspiration cytology and biopsy preparations obtained from equally divided transport medium specimens were compared in a study comprising 104 palpable breast lesions and 29 other miscellaneous lesions. In general, fine needle aspiration biopsy provided better information on tumour origin and differentiation than fine needle aspiration cytology, particularly with systemic aspirates and those which were heavily bloodstained. In most instances fine needle aspiration biopsy also provided sufficient material to perform specialised staining and immunohistological techniques, and it is suggested that it may have a role in supplementing direct smear fine needle aspiration cytology in these areas.

Biopsy, Needle↗
PubMedDate not supplied

Surveillance for dust storms and respiratory diseases in Washington State, 1991.

Southeast Washington State, which has a long history of seasonal dust storms, experienced 2 d of dust storms in October 1991, during which PM10 levels exceeded 1,000 micrograms/m3 (i.e., six times greater than the Environmental Protection Agency's 24-h PM10 standard). Three community hospitals in southeast Washington were visited for the purpose of assessing the possible effects of dust storms on respiratory health. During these visits, the number of emergency room visits for respiratory disorders for each day of 1991 were abstracted. These numbers were compared with daily PM10 levels for 1991. Also determined were the observed/expected ratios for the number of emergency room visits for each respiratory disorder category during October 1991. The maximum observed/expected ratio for the respiratory disorders was 1.2. For 1991, we found a 3.5% increase in the number of daily emergency room visits for bronchitis for each 100 micrograms/m3 increase in PM10. In addition, 2 d subsequent to those days on which the PM10 levels exceeded 150 micrograms/m3, there was a 4.5% increase in the number of emergency room visits for sinusitis for each 100 micrograms/m3 increase in PM10. Our results indicate that the naturally occurring PM10 in this setting has a small effect on the respiratory health of the population in general.

Air Pollutants↗
PubMedDate not supplied

Patient perception of quality of life after burn injury. Results of an eleven-year survey.

The purpose of this study was to assess how patients with burns perceive their physical, psychological, social, and economic status since their burn injuries and to examine the question, "Does burn severity or age at the time of injury affect the patient's perception of his or her quality of life after burn injury?" A 25-item questionnaire was mailed to 1837 former patients who had been hospitalized in our adult burn center from 1975 to 1987, and 245 (13.1%) completed questionnaires were returned. The chi 2 test suggests that the patient sample overall did not experience a change in perceptions after burn injuries. However, when the adult group is divided by burn severity (grouped into low and high percent of burn) and by age at the time of injury (grouped into young and old), both the young and the older persons with high burn severity identify impairments in their quality of life after burn injury.

Adaptation, Psychological↗
PubMedDate not supplied

The relationship of patient stress to burn injury.

The stress of burn injury can have an especially profound psychologic effect on individuals with recent histories of stress life events. A review of the literature reveals a model for this effect and documents the possibility of burn-prone patients, a concept that may explain the high number of patients with burns who also report a high level of stress before injury. This study was designed to assess the proportion of patients with burns reporting previous stress and to assess the relationship of this stress to burn injury and its exacerbating effects. A definite correlation between previous stress and burn injury was found, indicating that many patients with burns may have been in a vulnerable state at injury. Since such vulnerable patients will show a more severe reaction and more serious level of psychologic dysfunction than the seriousness of their injuries might indicate, their identification would have decided benefits in their psychologic rehabilitation.

Adaptation, Psychological↗
PubMedDate not supplied

Low national breast and cervical cancer-screening rates in American Indian and Alaska Native women with diabetes.

BACKGROUND: The cervical cancer mortality rate for American Indian and Alaska Native women is twice that of all races in the United States. To date the only published national breast and cervical cancer-screening rates for American Indian and Alaska Native women are based on self-reported data. When the Indian Health Service (IHS) conducts an annual audit on patients with diabetes, it includes cancer screening. This observational study presents national breast and cervical cancer-screening rates for American Indian and Alaska Native women with diabetes. METHODS: Cancer-screening rates were extracted from the 1995 diabetic audit for the 12 IHS areas. These rates were compared with rates for women without diabetes of the same age, 50 to 69 years, by chart review, at four IHS hospitals in the Aberdeen IHS area. RESULTS: Screening rates for women with diabetes in the 12 areas varied: mammogram (ever) 35% to 78%; clinical breast examination (last year) 28% to 70%, and Papanicolaou smear (last year) 26% to 69%. The Aberdeen IHS area women with diabetes had 51% more clinic visits per year than women without diabetes, but the groups had similar screening rates. CONCLUSION: Cancer-screening rates for American Indian and Alaska Native women vary by region. In the Aberdeen IHS area, women with diabetes had more visits (missed opportunities) but similar screening rates as women without diabetes. The diabetic audit could be used to monitor national IHS cancer-screening trends for women with diabetes and in the Aberdeen IHS area for all women aged 50 to 69 years.

Aged↗