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Biomedical subjects

M M Morin

Publications and source records attributed to M M Morin.

6 recordsLinked to original sources

NETGEN: generating phylogenetic networks with diploid hybrids.

SUMMARY: NetGen is an event-driven simulator that creates phylogenetic networks by extending the birth-death model to include diploid hybridizations. DNA sequences are evolved in conjunction with the topology, enabling hybridization decisions to be based on contemporary evolutionary distances. NetGen supports variable rate lineages, root sequence specification, outgroup generation and many other options. This note describes the NetGen application and proposes an extension of the Newick format to accommodate phylogenetic networks. AVAILABILITY: NetGen is written in C and is available in source form at http://www.phylo.unm.edu/~morin/.

Algorithms↗

Diagnostic x-ray procedures and risk of leukemia, lymphoma, and multiple myeloma.

Exposure to diagnostic x-rays and the risk of leukemia, non-Hodgkin's lymphoma (NHL), and multiple myeloma were studied within two prepaid health plans. Adult patients with leukemia (n = 565), NHL (n = 318), and multiple myeloma (n = 208) were matched to controls (n = 1390), and over 25,000 x-ray procedures were abstracted from medical records. Dose response was evaluated by assigning each x-ray procedure a score based on estimated bone marrow dose. X-ray exposure was not associated with chronic lymphocytic leukemia, one of the few malignant conditions never linked to radiation (relative risk [RR], 0.66). For all other forms of leukemia combined (n = 358), there was a slight elevation in risk (RR, 1.17) but no evidence of a dose-response relationship when x-ray procedures near the time of diagnosis were excluded. Similarly, patients with NHL were exposed to diagnostic x-ray procedures more often than controls (RR, 1.32), but the RR fell to 0.99 when the exposure to diagnostic x-ray procedures within 2 years of diagnosis was ignored. For multiple myeloma, overall risk was not significantly high (RR, 1.14), but there was consistent evidence of increasing risk with increasing numbers of diagnostic x-ray procedures. These data suggest that persons with leukemia and NHL undergo x-ray procedures frequently just prior to diagnosis for conditions related to the development or natural history of their disease. There was little evidence that diagnostic x-ray procedures were causally associated with leukemia or NHL. The risk for multiple myeloma, however, was increased among those patients who were frequently exposed to x-rays.

Adult↗

Breast cancer in women with scoliosis exposed to multiple diagnostic x rays.

Although exposure to ionizing radiation is a recognized risk factor for breast cancer, the potential hazard from low-dose, fractionated exposures during early breast development has not been thoroughly evaluated. Women with scoliosis represent a valuable population for studying this issue because they are exposed to multiple diagnostic x rays during childhood and adolescence, times when the breast may be highly sensitive to the carcinogenic effects of radiation. A study was conducted of 1,030 women with scoliosis who were seen at four Minneapolis area medical facilities between 1935 and 1965. The average age at diagnosis was 12.3 years; 60% of the women had idiopathic scoliosis. Individual x-ray films were counted and the number per patient ranged from 0 to 618 films (mean, 41.5). On average, the x-ray exposures were given over an 8.7-year period. Ninety percent of the women were located, of whom over 92% responded to a mail questionnaire or telephone interview. The average period of observation was 26 years. Overall, 11 cases of breast cancer were reported, compared with six expected (standardized incidence ratio = 1.82, 90% confidence interval = 1.0-3.0). Excess risk increased with time since exposure and was highest among those followed for more than 30 years (standardized incidence ratio = 2.4). Risk also increased with the number of x rays and with the estimated radiation dose to the breast (mean, 13 rad). These data suggest that frequent exposure to low-level diagnostic radiation during childhood or adolescence may increase the risk of breast cancer.

Adult↗

Drinking water source and mortality in US cities.

An apparent excess risk of all-cancer mortality among 473 of the largest US cities was found in relation to surface drinking water supplies. The increased risk for 100% surface water versus 100% ground water use was slight, about 2%, but statistically significant. This finding agrees with reports from several earlier studies in smaller geographical regions of the US, Great Britain and Canada. A relationship was further supported by the replication of this association within the larger of the 11 independent regions studied. Our data suggest that the association with surface water may be specific to cancer mortality. The increased risk would be expected to be greater than 2% if analyses were restricted to cancers of sites previously related to the use of surface drinking water.

Carcinogens, Environmental↗

Geographic patterns of ethnic groups in the United States.

The geographic distributions of 11 major ethnic groups within the United States, based on 1960 census data, are illustrated by computer-generated state economic area maps. The Scandinavian, German, and Russian ethnic groups were similarly concentrated primarily in the North Central region, while the Irish, Polish, Other East European, and South European groups were clustered predominantly in the Northeast. Other ethnic groups had patterns which were different from either of the above. These maps correspond to the atlases of mortality from cancer and other diseases.

Demography↗

Canine biliary carcinoma: epidemiological comparisons with man.

A retrospective study of abstracted data representing 1.1 million hospital examinations of dogs at veterinary university teaching facilities identified 77 with bile duct carcinoma. Using the hospital population, based on patient years at risk, as the expected frequency of particular zoographic characteristics, there was a suggestion of a familial (breed) predisposition in Labrador retrievers and limited evidence of a sex differential. Because mongrel dogs displayed about the same frequency of bile duct cancer as all breeds combined, other causal factors, besides genetics, are implied. A possible association was detected between canine cholangiocarcinoma and host infection by canine hookworms and/or whipworms. Human infection from hookworms (Necator americanus) and whipworms (Trichuris trichiura) is common in the southern rural areas of the U.S.A. (e.g. Appalachia), and tropical and sub-tropical countries of Africa, Central and South America, where there have been unexplained high rates reported for human biliary cancer. It is possible that the presence of these blood-letting nematodes, like a number of other parasites (ascarids, flukes and protozoa), may be related to the occurrence of human cholangiocarcinoma.

Animals↗