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Biomedical subjects

F L Williams

Publications and source records attributed to F L Williams.

At least 37 records · Page 2Linked to original sources
PubMed1995

Sex ratios of births, mortality, and air pollution: can measuring the sex ratios of births help to identify health hazards from air pollution in industrial environments?

OBJECTIVES: To compare the sex ratios of births and mortality in 12 Scottish localities with residential exposure to pollution from a variety of industrial sources with those in 12 nearby and comparable localities without such exposure. METHODS: 24 localities were defined by postcode sectors. SMRs for lung cancer and for all causes of death and sex ratios of births were calculated for each locality for the years 1979-83. Log linear regression was used to assess the relation between exposure, sex ratios, and mortality. RESULTS: Mortalities from all causes were consistently and significantly higher in the residential areas exposed to air pollution than in the non-exposed areas. A similar, but less consistently significant, excess of mortality from lung cancer in the exposed areas was also found. The associations between exposure to the general air pollution and abnormal sex ratios, and between abnormal sex ratios and mortality, were negligible. CONCLUSIONS: Sex ratios were not consistently affected when the concentrations or components of the air pollution were insufficiently toxic to cause substantially increased death rates. Monitoring of the sex ratio does not provide a reliable screening measure for detecting cryptic health hazards from industrial air pollution in the general residential environment.

Air Pollutants↗
PubMed1993

Applications of extraction mapping in environmental epidemiology.

This paper discusses a new method which allows the extraction of a background disease rate from a data set consisting of spatial co-ordinates of morbidity or mortality events. We demonstrate its application with two data sets, one based on cancer registry data and the other on death certificates.

Air Pollutants↗
PubMed1993

Effects of feeder cattle frame size, muscle thickness, and age class on days fed, weight, and carcass composition.

Feeder steers (n = 189) representing nine frame size x muscle thickness subclasses were started on a high-concentrate diet as calves, yearlings, or long yearlings and slaughtered at a constant s.c. fat thickness (13.5 mm) to determine the effects of feeder cattle frame size (large, medium, small), muscle thickness (No. 1, No. 2, No. 3), and age class on carcass traits and composition. After slaughter, one side of each carcass was physically separated into muscle, fat, and bone. Subcutaneous, intermuscular, and internal fat depot percentages were calculated as proportions of total fat weight. Effects of age class, frame size, and muscle thickness were significant for time-on-feed, slaughter weight, and carcass weight. Among age classes, long yearling steers required the fewest (P < .05) days on feed and heaviest (P < .05) live weights to reach the fat thickness end point. Increased frame size and decreased muscle thickness were associated with greater time-on-feed and heavier weights at slaughter. However, the effects of muscle thickness on slaughter traits were not consistent among frame and age subclasses; effects were greatest among large-framed steers and smallest among long yearling steers. Compositional differences (P < .05) were noted among age and muscle subclasses. Long yearling steers had the lowest (P < .05) percentage of bone among all age classes and a higher (P < .05) percentage of fat than steers fed as calves. No. 2 steers had the highest (P < .05) percentage of bone and the lowest (P < .05) muscle:bone ratio among muscle thickness groups; no (P > .05) compositional differences were observed between No. 1 and No. 3 steers. Differences in muscle:bone ratio, though statistically significant, were relatively small in magnitude and were not directionally consistent with differences in muscle thickness. Differences in fat partitioning were noted among frame and muscle subclasses. Large-framed steers had the lowest (P < .05) percentage of s.c. fat and the highest (P < .05) percentage of internal fat among frame sizes. No. 3 steers deposited the lowest (P < .05) percentage of intermuscular fat and the highest (P < .05) percentage of internal fat.

Adipose Tissue↗
PubMed1992

Low sex ratios of births in areas at risk from air pollution from incinerators, as shown by geographical analysis and 3-dimensional mapping.

Previous research in environmental and occupational health has suggested that fluctuations in the sex ratios of births might provide a useful early warning to the possible health effects of toxins or other stresses in the environment. To examine further this hypothesis, we investigated the sex ratios of births in an area in central Scotland which contained two incineration plants. Analyses of the sex ratios, at various levels of geographical detail and using 3-dimensional mapping techniques, in the residential areas at risk from airborne pollution from these incinerators showed locations with statistically significant excesses of female births.

Air Pollution↗
PubMed1992

Effect of frame size, muscle score, and external fatness on live and carcass value of beef cattle.

Commercial slaughter steers (n = 329) and heifers (n = 335) were selected to vary in slaughter frame size and muscle thickness score, as well as adjusted 12th rib fat thickness. After USDA carcass grade data collection, one side of each carcass was fabricated into boneless primals/subprimals and minor tissue components. Cuts were trimmed to 2.54, 1.27, and .64 cm of external fat, except for the bottom sirloin butt, tritip, and tenderloin, which were trimmed of all fat. Four-variable regression equations were used to predict the percentage (chilled carcass weight basis) yield of boneless subprimals at different fat trim levels (.64, 1.27, and 2.54 cm) as influenced by sex class, frame size, muscle score, and adjusted 12th rib fat thickness. Carcass component values, total carcass value, carcass value per 45.36 kg of carcass weight, and live value per 45.36 kg of live weight were calculated for each phenotypic group and external fat trim level. Carcass fatness and muscle score had the most influence on live and carcass value (per 45.36 kg weight basis). Carcasses with .75 and 1.50 cm of fat at the 12th rib were more valuable as the trim level changed from 2.54 cm to .64 cm; however, for carcasses with 2.25 cm of fat at the 12th rib, value was highest at the 2.54 cm trim level. Value was maximized when leaner cattle were closely trimmed. There was no economic incentive for trimming light-muscled or excessively fat carcasses to .64 cm of external fat.

Adipose Tissue↗
PubMed1992

Development of a quantitative quality grading system for mature cow carcasses.

Data from 400 cow carcasses were used to develop a new quality grading system. First principal component (FPC) values were determined for shear force (SHR) and palatability attributes of tenderness, connective tissue amount, flavor, and juiciness (JUC). Associated eigenvector load values for those traits were -.48, .54, .51, .46, and .05, respectively, and FPC values ranged from -3.20 to 2.18. Linear regression, using FPC as the independent variate, and SHR and palatability attributes (8-point scale, where 8 was highest) as dependent variates explained a significant amount of variation (P less than .001) in all traits, except JUC, and resulted in R2 values of .71, .89, .80, .66, and .01, respectively. A predictive quality-grade equation was developed using FPC as the dependent variate, and overall maturity (OM), lean color, marbling score (MS), lean firmness, lean texture, fat color (FC), and marbling fineness ([marbling texture + marbling distribution]/2; 8-point scale, where 8 was highest) as independent variates. The resulting best-fit prediction equation (FPC = -.052-[.0031 x OM] + [.0013 x MS] + [.31 x FC]) explained a significant amount (P less than .001) of variation in FPC with R2 = .53, Cp = 15.0, and residual standard deviation = .69. A short-cut equation was developed from this prediction equation. Simple correlations for OM, MS, and FC with FPC were -.56, .39, and .64, respectively. Cow carcasses were assigned to one of three quality grades based on FPC values that corresponded with predetermined acceptability levels for each palatability trait. Newly developed grades were quantitative and less variable than existing grades. Future grades for cow carcasses should include fat color to predict palatability.

Adipose Tissue↗
PubMed1992

Development of a multivariate yield grade equation to predict compositional traits in mature cow carcasses.

Data from 68 cow carcasses were used to develop a new yield grading system. First principal component (FPC) values for compositional attributes (LNFT = separable lean weight/[lean+fat weight] x 100, LNBN = separable lean weight/[lean+bone+connective tissue weights] x 100, and BTPR = [defatted lean from the round, loin, rib, and chuck]/side weight x 100) were determined. The first component explained 83.5% of the standardized variance and load values were .63, -.52, and .58, respectively. The resulting FPC values ranged from -1.93 to 1.89. The linear regression of LNFT, LNBN, and BTPR (dependent variables) on FPC (independent variable) explained a significant amount of variation (P less than .001) in each case and resulted in R2-values of .98, .67, and .85, respectively. A best-fit yield grade equation, developed to predict FPC, included adjusted fat thickness (ADF), percentage of kidney, pelvic, and heart fat (KPH), and overall muscling grade (OM). The equation, FPC = 2.04 - (.67 x ADF) - (.21 x KPH) - (.0016 x OM), explained a significant amount (P less than .001) of variation in FPC with R2 = .94 and residual standard deviation = .25. Simple correlations for ADF, KPH, and OM with FPC were -.87, -.71, and -.80, respectively. Cow carcasses were assigned to one of three grades based on FPC values that corresponded with predetermined levels of LNFT, LNBN, and BTPR. These grades generally had smaller CV than existing grades. When used in conjunction with quality grades, proposed grades could be more useful to the cow meat industry.

Abattoirs↗
PubMed1992

Beef carcass composition of slaughter cattle differing in frame size, muscle score, and external fatness.

Commercial slaughter steers (n = 329) and heifers (n = 335) were selected to vary in slaughter frame size and muscle thickness score, as well as carcass adjusted 12th-rib fat thickness. After collection of USDA carcass grade data, one side of each carcass was fabricated into boneless primals, subprimals, and minor tissue components. Cuts were trimmed to 2.54, 1.27, and .64 cm of external fat, except for the knuckle, tri-tip, and tenderloin, which were trimmed of all fat. Forced four-variable regression equations were used to predict the percentage (chilled carcass weight basis) yield of boneless subprimals at the three fat trim levels as influenced by sex class, frame size, muscle score, and adjusted 12th-rib fat thickness. Independent variables that had the most influence on percentage yield of primals and boneless subprimals were adjusted 12th-rib fat thickness and sex class. Within the same phenotypic group, percentage of trimmable fat increased by 2.32% as 12th-rib fat thickness increased by .75 cm. Estimated percentage yield of the major subprimals from the loin and round tended to be higher or relatively equal for heifer carcasses at all trim levels compared with those subprimals from steer carcasses. Holding frame size, sex class, and fat thickness constant, there was a higher percentage yield of chuck roll, rib eye roll, and strip loin for carcasses from thick-muscled cattle than for those from average- and thin-muscled cattle. Frame size had little effect on percentage yield of boneless subprimals.

Abattoirs↗
PubMed1991

Toxicity from ragwort and fat cow syndrome, or from industrial chemicals: the value of epidemiological analysis for interpreting clinico-pathological findings.

When livestock in close proximity to industries develop signs of ill-defined disease, toxic effects from industrial pollution should be considered in the differential diagnosis. In establishing the final diagnosis, epidemiological methods should be applied to supplement the clinical and pathological techniques. This viewpoint is illustrated by two case-histories describing episodes of cattle disease in central Scotland. A long-established and successful dairy herd in central Scotland sustained severe morbidity and mortality amongst animals which had grazed on a field beside a recently established dump which contained wastes from a chemical waste incinerator. An official investigation concluded that the episode of disease was the result of ragwort poisoning; this diagnosis was reached on clinical and pathological grounds only. A similarly unexpected and severe epidemic occurred a few years later in another dairy herd, about 1 km further away from that incinerator (which was also within 100 m of a municipal incinerator). The official investigation, which again focused on clinical and pathological criteria, led to the diagnosis of fat cow syndrome. In the first episode, contaminated water drained from the chemical waste dump on to the cows' field; in the second episode, the relevant field was affected by airborne pollution from the two waste incinerators mentioned earlier. In both episodes, the epidemiological features, which were not examined systematically by the original investigators, were consistent with the hypothesis that these episodes resulted from exposures to toxic contaminants.

Animals↗
PubMed1991

Deaths from road traffic accidents in Scotland: 1979-1988. Does it matter where you live?

The purpose of this study was to calculate and compare the geographical distributions of male and female deaths from road traffic accidents in Scotland. A retrospective, nationwide study of deaths from road traffic accidents was undertaken; all road traffic deaths between 1979 and 1988 were included. Deaths were abstracted from the Annual Reports of the Registrar General for Scotland. Standardized mortality ratios (SMRs) for males and for females were calculated for 1979-83 and 1984-88. Maps showing the distributions of high SMRs (SMR greater than 135 or P less than 0.05) and low SMRs (SMR less than 65 or P less than 0.05) were prepared for males and females separately. The geographical distributions of deaths from road traffic accidents in Scotland were dissimilar to those of England and Wales. For both sexes, high mortality was predominantly in the sparsely populated regions of the north and south of Scotland; whereas low mortality was found in the cities and the populous central belt. Possible reasons for this pattern are discussed: speed, response time (both of notification of the accident and of arrival of the ambulance), distance to nearest hospital with suitable emergency facilities, and road conditions.

Accidents, Traffic↗
PubMed1991

Trends in lung cancer mortality in Scotland and their relation to cigarette smoking and social class.

This paper describes the trends in lung cancer rates in Scottish men and women during 1959-85, the relationship between lung cancer and cigarette consumption, and between lung cancer and social class, and the urban-rural gradient of lung cancer. Lung cancer rates in Scottish men have declined in all age groups under the age of 74 for at least the past two decades; the most notable decrease was in men aged 40-44 years, whose rates halved between 1970 and 1980. In women, who began smoking in large numbers only after World War II, lung cancer mortality declined slightly in those between 40-54 years and rose in those over 54 years. Trends in cigarette consumption did not fully explain the decline in lung cancer. Marked urban-rural gradients in the SMRs for lung cancer were evident in all periods, and these strengthened over time. Correlations between lung cancer and social class differed markedly from those found in previous studies, except for those with social classes II and V.

Adult↗
PubMed1991

Deposition and distribution of carcass fat for steers differing in frame size and muscle thickness.

Yearling feeder steers (n = 324) representing nine frame size (Large, Medium, Small) x muscle thickness (No. 1, No. 2, No. 3) subclasses were serially slaughtered at 28-d intervals during a 140-d finishing period. Weights for total dissectible (TDF) and subcutaneous fat (SQ) from each of nine wholesale cuts were recorded. Resulting data were analyzed using allometry (Y = aXb and Y = aXb10cx) to characterize deposition patterns for fat and to determine effects of feeder cattle frame size (F) and muscle thickness (M) on relative fat deposition and distribution. Patterns of TDF and SQ deposition were similar among cuts. As the steers became fatter, relative proportions of TDF and SQ in the abdominal and dorsal regions of the carcass increased and relative proportions of fat in the distal regions decreased. There was a tendency for the growth impetus of TDF and SQ to shift from the ventral portions of the carcass toward the dorsal region of the carcass as fattening progressed. Despite significant among-class differences in allometric coefficients, relative proportions of TDF and SQ in the nine wholesale cuts were remarkably similar for all nine F x M subclasses when compared at a constant percentage of total carcass fat. At endpoints of either a constant fat thickness measurement or a constant USDA marbling score, subclass differences in fat distribution were negligible.

Adipose Tissue↗
PubMed1991

A review of aging of dental components and a retrospective radiographic study of aging of the dental pulp and dentin in normal teeth.

A review of aging of dental components is followed by a clinical radiographic study. Patients received radiographs at 5-year intervals with a 10-year minimum followup. Data obtained were age, gender, tooth, and systemic diseases. Measurements taken were tooth length, coronal length, apical length, cervical width, midroot width, and apical width. Root canal shrinkage was calculated vertically, horizontally, and as a combination (vertical and horizontal). Results showed statistically significantly more shrinkage in men, the elderly, and people with calcification-related diseases. Shrinkage increased with advancing age. With further studies, radiographically determined root canal measurements could prove useful in anthropology, forensics, and as a biomarker of aging.

Adult↗
PubMed1990

Mortality at early ages in Scottish communities, 1959-83: geographical distributions and associations with selected socioeconomic indices.

Mortality at early ages has long been known to reflect the general health of communities, and derived epidemiological parameters have been used to indicate those communities to which policies of environmental improvement and health promotion should be directed. The geographical distributions of stillbirths, and perinatal, neonatal, post-neonatal and infant mortalities in Scottish communities were analysed for the years 1959-63, 1969-73 and 1979-83. For all categories of mortality, urban-rural gradients were present in the earlier periods, but had disappeared by 1979-83. Several communities were identified which had high rates for at least two categories of mortality, and which may benefit, therefore, from intervention programmes. For 1979-83 only, bivariate correlation coefficients were calculated between the five categories of mortality and four socio-economic variables: social class, overcrowding (over 1.5 persons per room and persons per hectare), single parent households and housing tenure. For stillbirths and perinatal mortality, significant correlations were found with persons per room, housing tenure and social class. Neonatal and postneonatal mortalities were significantly correlated with council house tenure and persons per hectare respectively, whereas infant mortality was not significantly correlated with any variable. Multiple regression, using the five categories of mortality as dependent variables and social class, persons per room, persons per hectare, housing tenure and single parent families as the independent variables, showed that these socioeconomic characteristics explained between 10-32% of the variation in mortality.

Fetal Death↗
PubMed1990

Gastric and colorectal cancers in Scotland: a study of the geographical distributions and selected associations.

The geographical distributions of gastric and colorectal cancers in Scotland were investigated by analysing the data available for those diseases in the Annual Reports of the Registrar General for Scotland. For gastric cancer, the standardised mortality ratios (SMRs) for the 234 traditional communities in 1969-73 and for the 56 districts in 1979-83 were calculated. For colorectal cancer, only the data for the latter period were available, and SMRs for that period were calculated similarly. Possible determinants on the resulting pattern of high and low SMRs were investigated. Gastric cancer was generally associated with industrial and urban environments, particularly in west central Scotland, although mortality in Dundee was high in both periods; this cancer also showed significant negative correlations with social class II. By contrast, colorectal cancer showed no strong geographical pattern, no urban-rural gradient, and no social class associations. The cancers showed a weak association with each other.

Colonic Neoplasms↗
PubMed1990

Effect of plane of nutrition and age on carcass maturity of sheep.

One hundred twenty ewe and wether lambs were fed high (76% TDN, 12.3% crude protein) or low (70.6% TDN, 16.1% crude protein) energy diets and slaughtered at average ages of 261, 356 or 469 d. High planes of nutrition for lambs at 356 or 469 d of age resulted in heavier carcasses, thicker fat depth and higher flank streaking scores compared to lambs fed low planes of nutrition. Rib bone, break joint and overall maturity scores were not influenced (P greater than .05) by diet. Metacarpal and metatarsal bones from lambs fed high planes of nutrition were slightly longer and heavier and required more force to break (P less than .05) compared with bones from lambs fed low planes of nutrition. The majority of the ewes fed high or low planes of nutrition had fused growth plates and possessed spool joints by 469 d; none of the wethers had spool joints. An additional 27 wethers were slaughtered at an average of 480, 578 or 662 d. Rib bone, break joint and overall maturity scores were not different (P greater than .05) for animals fed the high or low energy diets, but bone weight and shaft break force values were higher for those fed high energy diets. At 662 d of age, only 20% of the wethers on each dietary regimen possessed fused growth plates. Overall, plane of nutrition in market-weight lambs and yearlings had very little influence on the presence or absence of a break joint or on other bone maturity scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1990

Comparison of market hog characteristics of pigs selected by feeder pig frame size or current USDA feeder pig grade standards.

Two feeder pig grading systems were tested. Forty-five barrows were selected using current USDA Feeder Pig Grade Standards (U.S. No. 1, No. 2 and No. 3). Additionally, 45 barrows were selected using three frame sizes (large, medium and small). Pigs were slaughtered at 100, 113.5 of 127 kg live weight. Trimmed four lean cuts were separated into soft tissue, skin and bone. The skinless belly and soft tissue from the four lean cuts were ground separately and analyzed chemically. Data from each grading system were analyzed separately in a 3 X 3 factorial plan. Pigs selected using current USDA grade standards differed (P less than .05) for last rib backfat, 10th rib fat depth, longissimus muscle area, percentage of trimmed four lean cuts and USDA carcass grade. In the frame size system, pigs with large frame size had less last rib backfat, less 10th rib fat depth, longer carcasses, higher percentage of four lean cuts and superior USDA carcass grades than pigs with small frame size did (P less than .05). The Bradley and Schumann test of sensitivity showed that selection by frame size was more sensitive than current USDA grade standards for discriminating feeder pig foreleg length, body depth and ham width. In addition, selection by frame size was more sensitive than current USDA grade standards for discriminating carcass length and carcass radius length. No increase in sensitivity (P greater than .10) was noted for carcass composition or growth traits over the current USDA Feeder Pig Grade Standards.

Animals↗