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Biomedical subjects

C Percy

Publications and source records attributed to C Percy.

At least 19 recordsLinked to original sources
PubMed1997

Non-Hodgkin's lymphoma among people with AIDS: incidence, presentation and public health burden. AIDS/Cancer Study Group.

We describe the anatomic and histologic presentation and prognosis of non-Hodgkin's lymphoma (NHL) among people with AIDS (PWA) and determine their contribution to the NHL burden. We linked AIDS and cancer registries in selected areas of the United States and compared NHL sites and histologies in PWA and non-PWA, after adjusting for age, sex and ethnicity. Among 51,033 PWA, we found 2,156 cases of NHL (4.3%). Half of NHL cases occurring post-AIDS were not reported to AIDS registries. NHL was part of an AIDS-defining condition for 3.2% of all PWA; the relative risk of NHL with 3.5 years of another AIDS diagnosis was 165-fold compared to non-PWA within the cancer surveillance system. Of NHLs, 39% were high grade (vs. 12% among non-PWA), 60% were nodal (vs. 74% among non-PWA) and 15% had brain primaries (vs. 1% among non-PWA). Excluding brain sites, extranodal sites were still 20% more common than expected. Relative risk was elevated for all histologic types, with the risk ranging from 652-fold for high-grade diffuse immunoblastic tumors and 261-fold for Burkitt's lymphomas to 113 for intermediate-grade lymphoma to 14-fold for low-grade lymphoma. Survival among PWA with NHL was poor, and tumor grade had little impact. In high-risk AIDS areas, AIDS-related NHLs constitute a major share of the NHL burden. We conclude that NHL risk is considerably under-estimated in AIDS registry data. The major differences between PWA and non-PWA were the high frequency of brain lymphoma and the increase in high-grade lymphomas in PWA. However, the grade of NHL did not influence the prognosis among PWA with lymphoma. The increasing risk of NHL in PWA has contributed substantially to the general increase in NHL rates in the United States since 1981.

Adolescent↗
PubMed1997

Prevalence of hypertension among Navajo Indians: findings from the Navajo Health and Nutrition Survey.

Hypertension and other chronic diseases are becoming increasingly important health problems for many Native American people, including the Navajo. A community-based survey that included three standardized measurements of blood pressures, was conducted during 1991-92 on the Navajo Reservation. Among the 780 adults examined, the overall age-standardized prevalence of hypertension, defined as an elevated systolic (> or = 140 mm Hg) or diastolic (> or = 90 mm Hg) blood pressure, or possession of prescription antihypertensive medications, was 19% (24% among men and 15% among women). The prevalence of hypertension increased with age and relative weight, and among men, was associated with diabetes mellitus. Among women, hypertension was associated with a central distribution of body fat, cigarette smoking, self-reported diabetes mellitus and impaired glucose tolerance. Although only 50% of the persons found to have elevated blood pressure at the examination reported they had been previously told that they had hypertension, persons who had been previously diagnosed with hypertension had a slightly higher rate (approximately 60%) of blood pressure control than that seen in the general U.S. population. On the basis of these results, the prevalence of hypertension among the Navajo appears to have substantially increased since the 1930s. Improved prevention and management of hypertension, especially for overweight and diabetic individuals, may reduce morbidity and mortality from cardiovascular and renal disease.

Adult↗
PubMed1997

Immunodetection of PrPSc in spleens of some scrapie-infected sheep but not BSE-infected cows.

The development of diagnostic tools for transmissible spongiform encephalopathies (TSEs) would greatly assist their study and may provide assistance in controlling the disease. The detection of an abnormal form of the host protein PrP in noncentral nervous system tissues may form the basis for diagnosis of TSEs. Using a new antibody reagent to PrP produced in chickens, PrP can be readily detected in crude tissue extracts. PrP from uninfected spleen had a lower molecular mass range than PrP from brain, suggesting a lower degree of glycosylation. A simple method for detecting the abnormal form of the protein, PrPSc, in ruminant brain and spleen has been developed. PrPSc was detected in sheep spleen extracts from a flock affected by natural scrapie and was also found in spleens from some, but not all, experimental TSE cases. In spleens from cattle with bovine spongiform encephalopathy (BSE) no PrPSc was detected. It is therefore suggested that there is differential targeting of PrPSc deposition between organs in these different types of TSE infection which, with other factors, depends on strain of infecting agent.

Animals↗
PubMed1995

Cancer. Introduction.

This supplement presents the study of various histologic types of cancers diagnosed in the populations covered by the Surveillance, Epidemiology, and End Results (SEER) Program. It describes the SEER program and the coding of histologic type by the International Classification of Diseases for Oncology. Each of the 19 articles deals with the histologic types of cancer found in major sites or with specific histologic types, such as lymphomas or melanomas. Histologic types have been grouped based on those developed by Dr. John Berg. Data presented in this supplement are based on more than one million microscopically proven invasive cancers and 98,000 in situ cancers diagnosed during the period 1973-1987 in areas covered by the SEER Program.

Adolescent↗
PubMed1992

Obesity among Navajo adolescents. Relationship to dietary intake and blood pressure.

We evaluated anthropometric measurements, blood pressures, dietary intakes, and self-perceived body image of 352 Navajo Indian adolescents. Thirty-three percent of the girls and 25% of the boys were obese according to a body mass index criterion. Navajo youth tended to have larger skinfolds than their white (National Health and Nutrition Examination Survey II) and Mexican American (Hispanic Health and Nutrition Examination Survey) counterparts, with the greater difference in the subscapular skinfolds indicating a greater amount of truncal rather than peripheral fat. When divided into lower, middle, and upper thirds of body mass index, systolic and diastolic blood pressures were positively related with increasing body mass index for girls, and systolic blood pressure and body mass index were related among boys. The high prevalence of obese adolescents and the apparent effect of the increased weight on blood pressure in this population indicate the need for interventions aimed at improving dietary habits and fitness levels.

Adolescent↗
PubMed1991

Is brain cancer mortality increasing in industrial countries?

This paper analyzes age-specific trends in brain and other central nervous system cancer mortality from 1968 to 1987 in several major industrial countries. It also examines changes in the use of diagnostic confirmation technology and trends in incidence in the U.S. National Cancer Institute, Surveillance, Epidemiology, and End Results (SEER) program from 1973 to 1987 to estimate the influence of diagnostic factors on recent mortality trends. Other sources of error have not been evaluated in this paper. Age-specific analyses of brain and other nervous system cancer mortality show drastic increases in persons ages 75-84 and consistent increases in younger age groups in most countries, although mortality declined in the U.S. in persons 0-24 by 2% annually. In the SEER program, brain cancer incidence increased significantly by 2%, 1%, and 5% annually in persons aged 0-44, 65-74, and 75-84, respectively. Throughout this time period, microscopic or radiographic confirmation occurred in at least 96% of all incident cases of brain and other central nervous system cancers diagnosed before death, with older persons receiving consistently more radiographic tests than younger persons. Changes in diagnoses across populations and over time are unlikely to account completely for these increasing trends which are occurring simultaneously in both males and females in major industrial countries. Additional studies need to be conducted, to exclude artifacts, to assist health care planners in anticipating treatment demands, and to detect preventable causes of these changing trends.

Adult↗
PubMed1990

Is brain cancer mortality increasing in industrial countries?

This paper analyzes recent age-specific trends in brain and other central nervous system cancer mortality from 1968 to 1986-1987 in the United States, United Kingdom, Italy, France, and West Germany. It also examines changes in the use of diagnostic confirmation technology in the U.S. SEER program from 1973 to 1987 to estimate the influence of such factors on recent mortality trends. Other sources of error have not been evaluated in this paper. In the United States and Sweden, deaths due to brain and other central nervous system cancer, adjusted to the overall population, are unchanging. However, age-specific analyses of brain and other nervous system cancer in six major industrial countries show markedly different trends at different age groups, with drastic increases in brain tumor rates in the old: rates doubled in persons ages 75 to 84. In the United States, microscopic or radiographic confirmation occurred throughout this time period in 96% of all incident cases of brain and other central nervous system cancers diagnosed before death in the SEER program, with older persons receiving consistently more radiographic tests than younger persons. The use of diagnostic technology may change over time and across populations, but it is not known to what extent it accounts for these increasing trends, which require careful additional study.

Adolescent↗
PubMed1989

International comparability of coding cancer data: present state and possible improvement by ICD-10.

These are only a few of the major findings of this international death certificate study but they should be enough to make epidemiologists and statisticians wary of international mortality figures and to realize that the World Health Organization must put some effort into improving the rules for selecting the underlying cause of death and to training the users to use them in a uniform manner; otherwise the huge and costly effort of revising the ICD-9 into ICD-10 will have been in vain because the mortality figures will not be internationally comparable.

Data Collection↗
PubMed1989

The international comparability of cancer mortality data. Results of an international death certificate study.

In preparation for the 10th revision of the International Classification of Diseases (ICD-10), a two-part study was undertaken to assess the international comparability of the coding, by the 9th revision (ICD-9), of death certificates mentioning cancer, to see whether there had been improvement since the 8th revision (ICD-8). Part I repeated a 1978 study in which nine countries coded the same 1,234 United States death certificates mentioning cancer by ICD-9. The proportion of disagreements in coding the underlying cause of death fell about 35% between 1978 and the present study. This reduction was probably due to the new more detailed rules for coding cancer death certificates given in ICD-9. To combat the criticism of the possible bias associated with using United States death certificates only, in Part II of the study, each of seven countries submitted about 100 certificates translated into English which had posed problems in coding cancer. Discrepancies in assigning the underlying cause of death were found for 54% of these problem certificates. The major types of problems identified were coding when multiple cancer sites were mentioned on the death certificate, whether to select heart disease or cancer as the underlying cause of death, and the interpretation of the coding rules. Better rules for ICD-10 must be provided for both physicians and coders if international comparability of cancer mortality data is to be achieved.

Abstracting and Indexing↗
PubMed1989

Prevalence of diabetes in a Navajo Indian community.

The age- and sex-adjusted prevalence of non-insulin-dependent diabetes mellitus (NIDDM) of 494 (76 per cent) Navajo adults living in a reservation community was 10.2 per cent, approximately 60 per cent greater than the estimated prevalence (6.4 per cent) in the general US population. The screening protocol utilized likely underestimates the prevalence of NIDDM in this population. A high proportion of Navajo people were overweight when compared to the general US population.

Adult↗
PubMed1985

Cancer data systems.

Explore the source record for details and available documents.

Abstracting and Indexing↗
PubMed1984

Non-Hodgkin's lymphomas. Application of the International Classification of Diseases for Oncology (ICD-O) to the Working Formulation.

International Classification of Diseases for Oncology (ICD-O) code numbers for the non-Hodgkin's lymphomas (NHL) are assigned to the new Working Formulation (WF). This will facilitate the coding of NHL cases by registrars and pathologists by providing a ready means of translation of terms utilized in most of the existing classification schemes. Additional code numbers and synonyms are suggested to accommodate all of the terms in the six major classification systems currently in use and to permit the coding of immunologic cell type when appropriate tests have been performed. To demonstrate how the assignment of these code numbers can be useful, over 8000 incidence cases from the Surveillance, Epidemiology and End Results (SEER) Program (1977-1980) were coded according to the WF groups and the data analyzed. The prognostic significance of the three major groups in the WF is confirmed for each group in the SEER data and comparisons are discussed with the NCI study.

Actuarial Analysis↗
PubMed1983

Surveillance, epidemiology, and end results lung cancer data applied to the World Health Organization's classifications of lung tumors.

Less than 1% of the lung cancer cases from the Surveillance, Epidemiology, and End Results (SEER) Program changed categories as a result of the World Health Organization's revision of histologic classifications of lung tumors. Of the 28,119 microscopically proved lung cancers reported to SEER in 1977-79, 32% were squamous cell carcinoma, 16% were small cell and/or oat cell carcinoma, 27% were adenocarcinoma, 8% were large cell carcinoma, and 5% were other specified types. A further 12% (approximately 3,500 cases) were reported with such nonspecific terms as bronchogenic carcinoma, carcinoma of the lung, and undifferentiated or anaplastic carcinoma. The magnitude of the use of these nonspecific terms showed the need for greater precision in reporting and recording data.

Carcinoma↗
PubMed1981

Accuracy of cancer death certificates and its effect on cancer mortality statistics.

A study to determine the accuracy of cancer mortality data was done using cancer deaths occurring during 1970 and 1971 in eight of the nine areas included in the Third National Cancer Survey (TNCS). Death certificates with an underlying cause of death of cancer were compared to the hospital diagnosis for 48,826 resident cases of single primary cancers. The underlying cause of death as coded on the death certificate was found to be accurate for about 65 per cent of the cancer deaths in this study. Misclassification problems occurred for colorectal cancer, the second leading cause of death from cancer. Colon cancer was overreported and rectal cancer was under-reported on death certificates. Other misclassification problems were found for cancers of the uterus, brain, and buccal cavity including most of its sub-sites. Physicians tended to report a non-specific site of cancer on the death certificate rather than the specific site identified by the hospital diagnosis.

Autopsy↗