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Biomedical subjects

B Stuart

Publications and source records attributed to B Stuart.

52 records · Page 3Linked to original sources

Fetal blood velocity waveforms in normal pregnancy.

A combination of pulsed echo and continuous wave Doppler ultrasound was used to obtain blood flow velocity signals from the umbilical arteries of 18 normal patients from the 16th until the 40th week of pregnancy. Audio frequency analysis of these signals yielded fetal blood velocity waveforms. Analysis of these waveforms demonstrated that the placenta is an organ of low vascular resistance and that placental resistance to blood flow declines with advancing gestational age in normal pregnancy.

Blood Flow Velocity↗

Infrared spectroscopic studies on the development of crystallinity in dental zinc phosphate cements.

An infrared spectroscopic study has been made of the development of crystallinity (hopeite) in dental zinc phosphate cements. Crystallization in the bulk of a cement is prevented only by the incorporation, in the liquid, of aluminum which forms complexes with phosphoric acid. The development of surface crystallinity is related to the chemical composition of the cement and the speed of the reaction. No acid phosphates are to be found in the matrix which consists solely of neutral orthophosphates.

Aluminum↗

Effect of angiotensin-converting enzyme inhibitor (SQ 20881) on the plasma concentration of angiotensin I, angiotensin II, and arginine vasopressin in the dog during hemorrhagic shock.

The effect of an angiotensin-converting enzyme inhibitor on the circulating levels of angiotensin I, angiotensin II, and arginine vasopressin was studied in dogs subjected to hypotensive hemorrhagic shock. In dogs subjected to hemorrhage but not given the inhibitor, angiotensin II rose 20-fold (from 69 to 1,343 pg/ml of plasma), whereas in dogs subjected to hemorrhage but pretreated with the inhibitor, angiotensin II rose only 2-fold (from 92 to 171 pg/ml of plasma). In the pretreated dogs angiotensin I rose 30-fold (from 108 to 3,232 pg/ml of plasma). There was no statistically significant difference between the vasopressin levels found in the untreated dogs and the levels found in dogs given the inhibitor (1,016 and 1,095 pg/ml of plasma). Of the 15 dogs in the untreated group, five died before retransfusion was completed (four of cardiac failure and one of cardiac arrhythmia); none of the 10 dogs in the inhibitor-treated group died. These observations suggest that the very high levels of angiotensin II observed following severe hemorrhage do not contribute significantly to the increased secretion of vasopressin and that the inhibitor protects against death, possibly by suppressing the very high blood levels of angiotensin II observed following this type of experimental hemorrhagic shock.

Angiotensin II↗

The assessment of the feto-placental circulation with continuous wave Doppler ultrasound.

Continuous wave Doppler ultrasound was used together with B-mode real time ultrasound to study feto-placental blood flow in utero. The results of 887 examinations on 221 patients are presented. The fetal heart rate acceleration slope and pulsatility index (P.I.) of the audiofrequency ultrasound display were analysed. There was a significant reduction in fetal heart rate (P less than 0.001) and P.I. (P less than 0.001) with advancing gestational age in normal pregnancy. In contrast, in retarded intrauterine growth a significant increase in P.I. values was observed in 77% of patients.

Blood Flow Velocity↗

Nurse-physician communication in home care and hospice: a physician's point of view.

As economic pressure continues to mount within the medical system, more and more patient contact is shifting away from expensive inpatient care. Initially, the shift in patient visits was away from the hospital and into clinics and the physicians offices. With the growth of capitated medical groups and prepaid care, not just inpatient days are declining. With efforts to control costs, the numbers of physician office and clinic visits are declining also.

Attitude of Health Personnel↗

Who bears the burden of Medicaid drug copayment policies?

This DataWatch examines the impact of Medicaid prescription drug copayment policies in thirty-eight states using survey data from the 1992 Medicare Current Beneficiary Survey. Findings indicate that elderly and disabled Medicaid recipients who reside in states with copay provisions have significantly lower rates of drug use than their counterparts in states without copayments. After controlling for other factors, we find that the primary effect of copayments is to reduce the likelihood that Medicaid recipients fill any prescription during the year. This burden falls disproportionately on recipients in poor health.

Aged↗

Dynamics in drug coverage of Medicare beneficiaries: finders, losers, switchers.

Although the vast majority of elderly Americans have the stability of basic Medicare benefits, Medicare alone offers no protection from the vicissitudes of the market for outpatient prescription drugs. This paper analyzes the sources and stability of prescription coverage maintained by Medicare beneficiaries in 1995 and 1996. The results show that fewer than half of all beneficiaries had continuous drug coverage over this period, while nearly a third gained, lost, or had spells without coverage.

Adult↗

Caregiving arrangement and nutrition: good news with some reservations.

The objective of this study was to assess the impact of caregiving arrangement on the iron and folate status of infants and toddlers reared at home or enrolled in centre-based, independent home, or licensed home care. One hundred and eighty-nine children aged 2 to 29 months were assessed 1 month prior to child care entry and at 6 months after entry into child care. Dietary (24-hour records), anthropometric (height, weight, head circumference) and biochemical (red blood cell folate, hematocrit, transferrin, and serum ferritin concentrations) methods were used to assess nutritional status. Frequency of illness was determined by a series of telephone interviews. Median intake of nutrients exceeded Canadian recommendations, regardless of care arrangement. Fifteen of 65 children had hematocrit values below age-specific cutoffs at the 6-month post-entry to child care visit. Children were frequently taken to obtain medical advice (average of 4 to 6 times during the study period) and 75% of subjects were prescribed at least one course of antibiotics. In conclusion, infants and toddlers in this study were generally well nourished, regardless of child care arrangement; however, iron status may remain an issue in this sample of infants and toddlers.

Adult↗

Which formula should be used in Ireland to estimate fetal weight?

In order to determine which formula most accurately predicts weight in Irish infants we performed a prospective study on 162 mothers within one week of delivery. Actual weights were compared with estimated weights derived from the formulae of Shepard; Hadlock; Birnholtz; Deter and Campbell. Overall the Deter formula gave the closest approximation of birth weight. All the formulae became increasingly inaccurate in the larger infants i.e. > 4 kg. However in infants of average weight the Campbell formula, which is based on a single measurement (A.C), is as good as any.

Birth Weight↗

The impact of insurance on access to physician services for elderly people with arthritis.

The impact of insurance on access to physician services among elderly individuals with chronic illnesses has far-reaching policy implications. Using a national probability sample of aged Medicare beneficiaries (N = 5,543), and controlling for severity of illness, comorbidities, and other covariates, we analyze this issue for the most prevalent, chronic disabling disease among the elderly: arthritis. The results from the two-part multivariate model (logistic regression followed by ordinary least squares regression) suggest that insurance status is a positive and statistically significant predictor of both initial access to care (p < .01), and amount of arthritis care used (p < .05). Taking the results of the two-part model, we conducted a microsimulation to estimate the increase in Medicare spending that would result if various types of Medicare supplemental insurance were provided to those who had none. Results suggest that Medicare expenditures would rise from $51 million to $59 million annually depending on the type of supplement provided.

Activities of Daily Living↗