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Biomedical subjects

A F Williams

Publications and source records attributed to A F Williams.

At least 163 records · Page 9Linked to original sources
PubMed1987

The effect of New York's seat belt use law on teenage drivers.

This study assessed the effects of New York State's recently adopted mandatory seat belt use law on teenage drivers. Teenage drivers were observed as they entered high school parking lots before the law was adopted, after it was adopted but before it was effective, one month after the effective date, and again five months after the effective date. The results showed that 14% of the teenage drivers were wearing either shoulder or lap belts or both prior to adoption of the law. This increased to 22% after adoption of the law, 60% one month after the effective date of the law, and 63% five months after the effective date. Teenagers using seat belts were more often female, were younger, had completed driver education and had a longer trip from home to school. Both before and after the law, teenage belt use was similar to, but typically lower than, belt use in the community in which the school was located.

Adolescent↗
PubMed1987

Results of a seat belt use law enforcement and publicity campaign in Elmira, New York.

In New York and other states in which seat belt use laws went into effect in the mid-1980s, belt use rates surged initially, then declined. This pattern of belt use also occurred in Canadian provinces that enacted laws in the mid-1970s; special enforcement programs reversed this trend. In late 1985 a three-week enforcement and publicity program was conducted in Elmira, New York. Belt use rates in Elmira were 49 percent before the program, 77 percent right after, and 66 percent two months later. In Glens Falls, a comparison city without a program, belt use declined from 43 percent to 37 percent during this interval. In a telephone survey after the campaign, Elmira respondents were more likely to say the belt use law was being strictly enforced and were more favorable toward it, compared to Glens Falls respondents. These data indicate that enforcement/publicity programs are an important and feasible method for increasing compliance with belt use laws.

Humans↗
PubMed1987

Shoulder belt use in four states with belt use laws.

Shoulder belt use was observed before and after belt use laws went into effect in New York, New Jersey, Illinois, and Texas. There were large increases in belt use rates in each state in the first month the laws were enforced. In the three states in which post-law observations were made more than once, belt use declined from the levels seen in the first month; rates generally dropped to less than 50 percent. This pattern of decline from initial use rates has also been found in other jurisdictions around the world. Combined enforcement and publicity campaigns have been shown to be capable of reversing this trend and to increase use rates to 65 percent or more. Such campaigns will be needed to maximize the effect of seat belt use laws in the United States.

Humans↗
PubMed1987

Antigens of activated rat T lymphocytes including a molecule of 50,000 Mr detected only on CD4 positive T blasts.

Mouse monoclonal antibodies (MAbs) have been prepared against rat T cell blasts. One MAb called MRC OX-40 recognized an antigen that differed from any previously described in that its expression was detected only on T blasts that also expressed the CD4 antigen. The OX-40 MAb did not detect an activation determinant of CD2 or CD4 molecules but recognized a distinct chain of mol. wt 50,000. The OX-40 MAb augmented T cell proliferation at late stages on in vitro responses. Other MAbs without obvious counterparts in other species were MRC OX-48 and MRC OX-49,50 which recognized cell surface molecules of mol. wts of about 95,000 and 90,000, respectively. The OX-48 antigen was not expressed on resting lymphocytes but was found on a subset of T and B blasts and also on other leucocytes. The OX-49,50 antigen was found on most haemopoietic cells but was expressed at greatly increased levels after lymphocyte activation and this was also the case for MRC OX-47 antigen which is of unknown Mr. The MRC OX-39 MAb was found to bind the rat IL-2 receptor; expression of this antigen was detected on thymic dendritic cells as well as on T blasts. The phenotype of rat T blasts compared to resting cells was also examined and changes in expression of L-CA, Thy-1, OX-2 and CD8 antigens were seen in addition to the changes found with the above MAbs.

Animals↗
PubMed1987

Long-term effects of losing a spouse or child in a motor vehicle crash.

In this article we examine the long-term effects of the sudden, unexpected loss of a spouse or child. In the spouse study, interviews were conducted with 39 individuals who had lost a spouse in a motor vehicle crash 4 to 7 years ago and with 39 matched controls. In the parent study, interviews were conducted with 41 parents who had lost a child in a crash and with 41 matched controls. Control respondents were matched to bereaved respondents case-by-case on the basis of sex, age, income, education, and number and ages of children. Significant differences between bereaved spouses and controls were revealed on several indicators of general functioning, including depression and other psychiatric symptoms, social functioning, psychological well-being, reactivity to good events, and future worries and concerns. For the most part, these differences persisted when variables such as present family income and present marital status were statistically controlled. Comparisons between bereaved and control parents also revealed significant differences on some measures of general functioning (especially depression), but these were not as pervasive as the differences obtained in the spouse study. Responses to questions about current thoughts and feelings suggest that the deceased continued to occupy the thoughts and conversations of bereaved spouses and parents. Moreover, a large percentage of respondents (from 30% to 85%, depending on the question), continued to ruminate about the accident or what might have been done to prevent it, and they appeared to be unable to accept, resolve, or find any meaning in the loss. Taken together, the data provide little support for traditional notions of recovery from the sudden, unexpected loss of a spouse or child.

Accidents, Traffic↗
PubMed1987

Evolutionary relationship between the T3 chains of the T-cell receptor complex and the immunoglobulin supergene family.

Antigen receptors on the surface of the thymus-derived (T) lymphocytes are associated with small integral membrane proteins called the T3 (CD3) gamma, delta, epsilon, and zeta chains. After interaction of the T-cell receptor with antigen, the T3 proteins are believed to transfer an activation signal to the intracellular compartment. In previous studies, the human gamma, epsilon, and delta chains have been cloned along with the mouse delta chain, but a relationship between these sequences and known molecular families has not been established. We now report the molecular cloning and characterization of the murine T3-epsilon protein and a sequence and structural analysis of the relationships between all the T3 chains and the immunoglobulin superfamily. It is established that the T3 chains are immunoglobulin-related and a particular relationship to the neural cell adhesion molecule (N-CAM) is noted. This sequence relationship adds interest to previous findings that the T3 chains are genetically linked to N-CAM and Thy-1 antigen on band q23 of human chromosome 11.

Animals↗
PubMed1987

Peptide and nucleotide sequences of rat CD4 (W3/25) antigen: evidence for derivation from a structure with four immunoglobulin-related domains.

The rat W3/25 antigen was the first marker antigen of helper T lymphocytes to be identified. Subsequently, the human OKT4 antigen (now called CD4) was described, and cell distribution and functional data suggested that W3/25 and OKT4 antigens were homologous. This is now confirmed by the matching of peptide sequences from W3/25 antigen with sequence predicted from rat cDNA clones detected by cross-hybridization with a cDNA probe for human CD4. Analysis of the two sequences suggests an evolutionary origin from a structure with four immunoglobulin-related domains, although only domain 1 at the NH2 terminus meets the standard criteria for an immunoglobulin-related sequence. CD4 domains 2 and 4 contain disulfide bonds but seem like truncated immunoglobulin domains, whereas domain 3 may have a pattern of beta-strands like an immunoglobulin variable domain, but without the disulfide bond.

Amino Acid Sequence↗
PubMed1987

Seat belt use law enforcement and publicity in Elmira, New York: a reminder campaign.

A three-week belt use law publicity and enforcement campaign in Elmira, New York, in November 1985, increased use from 49 per cent to 77 per cent; four months later belt use was 66 per cent. A reminder program, in April 1986, increased belt use to 80 per cent; use declined to 69 per cent four months later and to 60 per cent eight months later. Throughout these periods, belt use in Glens Falls, a comparison community, remained stable at just over 40 per cent.

Attitude↗
PubMed1986

High school driver education: further evaluation of the DeKalb County study.

The DeKalb County, Georgia, study is the largest experimental evaluation of high school driver education to date. Detailed reanalyses of data from that study reveal that students assigned to an enhanced driver education program (Safe Performance Curriculum) were more likely to obtain drivers licenses, to be in car crashes and to have traffic violations than control students not assigned to driver education. Students assigned to a minimal program of high school driver education (Pre-Driver Licensing Curriculum) were also more likely than control students to obtain licenses, but the difference was smaller than for the enhanced program and they were not significantly more likely to be in crashes or to have violations. Students in the more limited course were less likely than those in the enhanced course to complete the course in a timely manner, which suggests that exposure differences may explain differences between the two groups. The results confirm that greater availability of driver education causes students to become licensed sooner, although the DeKalb study probably underestimates the effect. Because of this greater exposure, crashes and violations are incurred at an earlier age.

Accidents, Traffic↗
PubMed1986

MRC OX-45 antigen: a leucocyte/endothelium rat membrane glycoprotein of 45,000 molecular weight.

Monoclonal antibodies MRC OX-45 and OX-46 detect identical or juxtaposed antigenic determinants on a novel rat membrane molecule that plays a possible role in macrophage suppression of antigen-induced T-cell responses. These antibodies react with most mature hematopoietic cells and their bone-marrow precursors, vascular endothelium and some connective tissue. The OX-45 antigens were purified from brain (mainly endothelium) and spleen by immunoaffinity chromatography, and were found to be glycoproteins with apparent Mr 43,000 and 45,000, respectively, as determined by SDS-PAGE analysis. The amino acid compositions of the two preparations were very similar but with no distinguishing features. The broad pattern of distribution was not the result of fortuitous cross-reaction of the MAbs as a single N-terminal sequence was obtained from mixed spleen populations of cells. Carbohydrate compositions of the brain and spleen molecules differed both in absolute amount (22 and 41% by weight, respectively) and in the ratios of various saccharides reflecting overall differences in the patterns of glycosylation between the two tissues. MRC OX-45 IgG showed an heterogeneity in the Mr of its H chain due to the attachment, in some molecules, of carbohydrate structures to the Fd fragment.

Animals↗
PubMed1986

Age differences of arrested and crash-involved drinking drivers.

Studies were reviewed to determine the extent to which drivers arrested for driving while intoxicated (DWI) and crash-involved drivers impaired by alcohol are similar in age. Data indicate that younger drivers are substantially underrepresented in the DWI arrest population relative to their presence in the alcohol-related crash population. Overall, the proportion of arrested drivers less than age 20 was only one-fourth to one-third the proportion of these drivers involved in fatal crashes, and for those aged 20-29 it was two-thirds to three-fourths. The reasons for the underrepresentation of young drivers in the arrested population are not fully known and require further study. Youthful drivers constitute the major part of the alcohol-related crash problem, and effective ways to address this population most at risk should be sought.

Accidents, Traffic↗
PubMed1986

Child restraint laws: an analysis of gaps in coverage.

The limiting effects of exemptions to the coverage of child restraint laws were estimated by determining the extent to which the laws would have applied to child motor vehicle occupants, ages 0-5 years, killed before the laws were passed (1976-80). The 50 state laws would have exempted about 39 per cent of child motor vehicle occupants less than 6 years of age killed in the years immediately preceding enactment of the laws. Of those children killed in pre-law years who were within the age limits set by the subsequent state laws, about 21 per cent would not have been covered. The gaps in the laws are unnecessary, and proper amendments based on these data can save lives.

Accidents, Traffic↗
PubMed1986

Seat belt use laws and occupant crash protection in the United States.

Current federal rule-making requires restraints such as air bags or automatic seat belts in new cars starting with model year 1987 unless states with two-thirds of the United States population enact seat belt use laws meeting certain criteria. Belt use laws have been enacted by 26 states and the District of Columbia as of July 1, 1986. The first laws to go into effect increased use from less than 20 per cent to 50-70 per cent in the first month; in most cases rates subsequently dropped to below 50 per cent. Texas has been an exception to this trend because it has had much tougher enforcement of its seat belt law than other states. This pattern is similar to the experience of Canadian provinces that passed laws in the mid-1970s; enforcement/publicity programs in Canada have produced belt use rates that are currently greater than 60 per cent. An enforcement program in Elmira, New York also increased use rates sharply. New York, which had the first and one of the strongest and most successful laws so far, had an estimated fatality reduction of 9 per cent during the first nine months of the law. It is likely that a 10 per cent reduction in fatalities is the maximum that can be expected from belt use laws without special enforcement efforts. Provision of automatic restraints in combination with belt use laws would greatly increase crash protection.

Accident Prevention↗
PubMed1986

Drinking and driving among high school students.

A questionnaire survey of high school students conducted in 1983 provided information on their self-reported drinking and driving practices. By age 15 the majority reported drinking alcoholic beverages. By age 17 half or more of the males and one-third of the females reported driving after drinking at least once in the past month. About one-quarter of the students estimated that six or more cans of beer would be required to make someone an unsafe driver. Reported frequency of driving after drinking was associated with less time spent on homework and poorer academic performance, working part time, greater participation in social activities, less perceived parental influence regarding their travel, owning a car, driving high mileage, speeding, and having crashes and violations.

Achievement↗
PubMed1986

Monoclonal antibodies against a rat leucocyte antigen block antigen-induced T-cell responses via an effect on accessory cells.

The MRC OX-45 and OX-46 mouse monoclonal antibodies recognize a rat cell surface glycoprotein of 45,000 MW that is present on a wide variety of haematopoietic cells and on endothelial cells. MRC OX-45 IgG or F(ab')2 blocked the primary mixed lymphocyte response (MLR) and the secondary response of T lymphocytes to the soluble antigen DNP-BGG. In contrast, the antibodies had no effect on the cytotoxic activity of specific (CTL) or non-specific (NK) killer cells or on proliferative responses stimulated by lectins or oxidative mitogenesis. The inhibitory effect was at the level of stimulator cells rather than responders since mouse anti-rat xenogeneic MLRs were inhibited but rat anti-mouse responses were unaffected. However, the effect was not a direct one because inhibition was seen when irradiated spleen cells were used as stimulators but not when cell populations highly enriched for dendritic cells were used. In the latter case, inhibition potentiated by antibody could be restored if a peritoneal cell population enriched for macrophages was added back to the cultures. The inhibitory effects of these monoclonal antibodies seem most likely to be due to potentiation of nonspecific suppression by macrophages.

Animals↗
PubMed1985

A glycophospholipid tail at the carboxyl terminus of the Thy-1 glycoprotein of neurons and thymocytes.

Cell surface molecules of eukaryotic cells have been considered to be integrated into the membrane bilayer by a transmembrane protein sequence. The Thy-1 antigen of rodent thymocytes and brain was the first eukaryotic membrane molecule for which biochemical data clearly suggested membrane integration via a nonprotein tail. Direct evidence is now presented showing that a glycophospholipid structure is attached to the carboxyl-terminal cysteine residue and that 31 carboxyl-terminal amino acids predicted from the Thy-1 complementary DNA sequence are not present in the mature glycoprotein. These experimental results raise questions concerning signaling across a cell membrane since antibodies to Thy-1 can stimulate T lymphocytes to release lymphokines and undergo cell division.

Amino Acid Sequence↗