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Biomedical subjects

D Dodge

Publications and source records attributed to D Dodge.

8 recordsLinked to original sources
PubMed1999

The use of benchmark dose methodology with acute inhalation lethality data.

Benchmark dose methodology has been proposed as a refinement to the no observed adverse effect level (NOAEL) methods currently used for health risk assessments. We compared log-normal probit and quantal Weibull benchmark concentration (BMC) estimates using 1, 5, and 10% response incidences with inhalation toxicity NOAELs and LOAELs from 120 acute lethality data sets. These studies yielded relatively steep dose-response slopes, which in turn influenced the suitability of selecting response incidences. The mean magnitude of difference between the 95% lower confidence limits (LCLs) for 1, 5, or 10% BMCs and corresponding NOAELs was less than twofold using the probit model and less than fourfold using the Weibull model. BMC estimates at the 10% response exceeded the observed LOAEL in some cases. Maximum likelihood estimates for doses with 1, 5, or 10% responses frequently exceeded LOAELs. The probit model repeatedly gave a better fit for the data compared with the Weibull model, resulting in improved goodness of fit tests and reduced 95% confidence intervals. The 95% LCL appears to be necessary at the 1, 5, or 10% response levels in order to safely estimate a concentration below that resulting in a LOAEL.

Aerosols↗
PubMed1987

Nonosmotic influences on osmotic stimulation of vasopressin in humans.

To study the influence of cardiopulmonary baroreceptor loading and unloading on the osmotic stimulation of arginine vasopressin (AVP) in normal humans, we gave 105-min 5% saline infusions (0.06 ml X kg-1 X min-1) to three groups of subjects under different cardiopulmonary baroreceptor loading conditions. Group A received only the infusion, with a consequent increase in central venous pressure (CVP) of 2.6 +/- 1.7 mmHg; group B had CVP held constant by continuous lower body negative pressure; and group C had CVP decreased by -3.3 +/- 1.4 mmHg, also with lower body negative pressure, for the duration of the infusion. Mean arterial pressure increased in group A by 6.6 +/- 3.7 mmHg, but did not change in groups B and C. On average, osmolality increased by the same amount in each of the three groups (11.6 +/- 3.3, 13.7 +/- 3.2, and 10.9 +/- 2.5 mosmol/kg, P = NS). The changes in AVP in the three groups were 3.6 +/- 2.0, 2.7 +/- 1.9, and 6.2 +/- 3.5 pg/ml, P less than 0.03, with group C different from group B and groups A and B not different by individual pairs testing. An independent effect of prolonged CVP reduction on AVP levels in group C was made unlikely by studies in four additional subjects in whom AVP did not change at constant osmolality during 105 min of CVP reduction comparable with that in group C. Thus modest loading of both cardiopulmonary and sinoaortic baroreceptors does not alter the osmotic stimulation of AVP in normal humans.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Response of plasma vasopressin to ethanol in congestive heart failure.

Plasma arginine vasopressin (AVP) levels are frequently increased in patients with congestive heart failure (CHF). Further, AVP does not respond normally to certain osmotic and nonosmotic manipulations in this condition. As a test of the central suppressibility of AVP in CHF, an oral ethanol challenge was given (0.7 ml/kg body weight) to 10 patients with CHF and 10 normal control subjects, and the response of AVP, osmolality, heart rate and blood pressure was measured over the next 2 hours. In the CHF group, AVP was 9.6 +/- 3.9 pg/ml (+/- standard deviation) at control and remained unchanged throughout the protocol. In the normal group, AVP was 6.9 +/- 2.9 pg/ml at control and declined significantly to 4.9 +/- 2.0 pg/ml at 20 minutes (p less than 0.05). Osmolality and blood ethanol changes were similar in the 2 groups, as were those in mean arterial pressure. The administration of ethanol therefore did not result in an acute decrease in plasma AVP in patients with CHF, but did so in normal subjects. Differences in the response of blood pressure and osmolality do not explain the abnormality; hence, a defect in the central control of AVP release may exist in CHF. This observation may have implications for the mechanisms involved in the generation or maintenance of elevated AVP levels in patients with this disease.

Arginine Vasopressin↗
PubMed1981

Graft survival with high levels of cytotoxic antibodies.

In this study, pretransplant transfusions significantly improved the survival of first cadaver kidney transplants. Large numbers of transfusions had the same influence on graft survival as small number of transfusions. Graft survival was not influenced by pretransplant antibody levels, and the beneficial effect of transfusions was also independent of highest pretransplant antibody levels. The positive relationship between transfusions and cytotoxic antibodies was shown to be highly significant. B-warm and T-warm antibodies were both increased by transfusions and tended to occur together. B-cold antibodies occurred independent of transfusions, B-warm and T-warm antibodies. The results of this study suggest, but do not confirm, that B-cold antibodies benefit graft survival, while T-warm antibodies adversely influence graft survival. Transfusions and B-cold antibodies appear to influence graft survival by different mechanisms.

Antibody Formation↗
PubMed1981

A course in collaboration for social workers and general practitioners.

Patients have overlapping social and medical needs, yet social workers and doctors often have problems in working together to help with them. We planned a short experimental course which was to look at this situation and to help members of both professions learn about each other. This was to encourage attitudes of mutual trust and respect in order to promote future collaboration.The social workers had all qualified within the past year and were working in their first appointment, based either in the community or in a hospital. The doctors were training to become general practitioners and were either members of a three-year vocational training programme or were working in a one-year attachment in local practices.Each session started and ended with the whole course together, but the core of each meeting was case discussion among small mixed groups. In this way social workers and doctors were able to explore together mutual problems of patient care.

Education, Medical, Graduate↗
PubMedDate not supplied

Screening-level ecological risk assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans in sediments and aquatic biota from the Venice Lagoon, Italy.

Recent monitoring data indicate that portions of Italy's Venice Lagoon ecosystem have been degraded due to biological and chemical pollution from a variety of potential sources. Using polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) data collected from sediment, fish and shellfish in the Lagoon, a screening-level ecological risk assessment (ERA) was performed to evaluate the risks to representative aquatic biota and wildlife receptors. Risks to aquatic invertebrates posed by PCDD/Fs in sediment were evaluated by comparing measured tissue concentrations in fish and shellfish to appropriate ecotoxicological reference values. For mammalian and avian receptors, risks posed by theoretical exposures to PCDD/Fs through the food chain were calculated using conservative wildlife exposure models. Results of the screening-level approach indicate that the potential for adverse effects to fish and aquatic invertebrate receptors from PCDD/Fs in surficial sediments are unlikely. Adverse effects to wildlife are possible but highly uncertain, and warrants further investigation in a more comprehensive ERA.

Animals↗