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Biomedical subjects

R J Montgomery

Publications and source records attributed to R J Montgomery.

14 recordsLinked to original sources
PubMed1995

The impact of respite use on nursing home placement.

The results of experimental studies of the effects of respite care have been difficult to interpret because researchers have lacked experimental control over who actually received the treatment. Data from one such study are reanalyzed, focusing on the linear relationship between amount of respite use and probability of nursing home placement at the end of the treatment period. The results indicate a significant negative relationship between amount of respite use and nursing home placement.

Aged↗
PubMed1994

A longitudinal analysis of nursing home placement for dependent elders cared for by spouses vs adult children.

Five-wave panel data from 531 informal caregivers and frail elders were analyzed using an event history framework to identify how changes in the caregiving situation are related to nursing home placement. The results indicate that the predictors of placement differ substantially for elders cared for by spouses vs those cared for by adult children. In addition, the findings suggest dramatically different descriptions of the caregiving role over time for the two groups of caregivers. There were differences not only in the conditions under which caregiving ends, but also apparent differences in when caregiving begins and how it is perceived by the caregiver. Differences in the probability of placement of elders cared for by spouses vs adult children are interpreted within the framework of these contextual differences in the caregiving role.

Adolescent↗
PubMed1990

Reaction of the circulatory system to injury and regeneration.

The anatomy of the bone blood supply is well known. Techniques to measure bone blood flow are available, but no accurate method is available for clinical use. Ion movement from the capillary to the matrix is by diffusion, and efflux appears to be controlled by a concentration-dependent binding mechanism in the extravascular space of bone. The resistance vessels of bone are regulated by local, neural, and humoral factors. Fractures of long bone provoke a decrease in blood flow followed by a large increase in blood flow driven by metabolic demand. Fractures heal by coordinated formation of new bone, which is a combination of interstitial and surface remodeling. Age affects bone remodeling. Fixation of an experimental fracture may modify blood flow as well as bone remodeling. Fluid fluxes in bone may produce streaming potentials that in turn stimulate the osteoblasts to form new bone.

Animals↗
PubMed1989

The effects of alternative support strategies on family caregiving.

Family units (N = 541) of impaired elderly persons and caregivers were randomly assigned to a control group or one of five treatment groups eligible for a variety of respite or educational services. After 12 months of service eligibility, caregivers of elderly persons remaining in the community reported lower levels of subjective burden. Services appeared to delay nursing home placement among families with adult child caregivers, but encouraged placement by spouse caregivers.

Adult↗
PubMed1988

Interstitial fluid flow in cortical bone.

After injection of ferritin into the tibial nutrient artery of adult dogs, ferritin was seen in the interstitial fluid compartment of the tibial cortex immediately and up to 25 min after injection. The pattern of movement was consistent with bulk interstitial fluid flow influenced by hydrostatic pressure. In osteons sectioned transversely, evidence was seen of centrifugal movement of ferritin in a halo pattern around the central capillary. Haloes in the superficial part of the cortex coalesced to form a ferritin front which moved toward the periosteal surface. Movement of ferritin was delayed by appositional bone of the periosteal surface. Ferritin was seen in channels in the matrix and perivascular spaces termed "matrix prelymphatics" and "perivascular prelymphatics," respectively, because they lacked an endothelial lining.

Animals↗
PubMed1988

Parathyroid hormone effects on skeletal exchangeable calcium and bone blood flow.

The effects of alterations in serum calcium levels on the volume of distribution of a calcium tracer in bone and on bone blood flow were investigated in dogs by manipulation of parathyroid status. The volume of distribution increases with increasing serum calcium. This implies that there is a concentration-dependent binding mechanism in the extravascular space of bone, which is not saturated at the levels of serum calcium achieved in these experiments. The skeletal exchangeable calcium was increased in hypercalcemic dogs and decreased in hypocalcemic dogs. Cancellous bone contains proportionately more exchangeable calcium than cortical bone. Bone blood flow was decreased by 50% 15 min after injection of a bolus of parathyroid hormone (PTH) but returned to control values by 240 min. Fifty-two hours after the induction of hypercalcemia with repeated doses of PTH, there was no difference in blood flow over control animals.

Animals↗
PubMed1987

Maternal serum alpha-fetoprotein screening: report of a Canadian pilot project.

A pilot project of maternal serum alpha-fetoprotein (MSAFP) screening was carried out in Ontario from 1982 to 1985 to examine the feasibility and acceptability of screening a prenatal population for open fetal neural tube defects. A total of 8140 patients at low genetic risk were screened. Patient acceptance was excellent. Blood samples were taken at 16 to 18 weeks' gestation. If the MSAFP level was elevated, the assay was repeated and an ultrasound examination performed. Amniocentesis was offered to 67 women with unexplained persistently elevated levels. The outcome of pregnancy was known in 7473 patients (91.8%). Seven of nine known open fetal neural tube defects were detected. All were confirmed, and no unaffected fetuses were aborted on the basis of the screening results. The rates of perinatal death (6.7%), intrauterine growth retardation (11.7%) and prematurity (23.3%) were significantly higher among the patients with unexplained elevated MSAFP levels than among those with normal levels (p less than 0.001). Of 20 patients with unexplained low levels, 10 subsequently had spontaneous abortions and 10 gave birth to term appropriate-for-gestational-age infants. Seven of nine patients who gave birth to infants with autosomal trisomy had MSAFP values below the median. The findings indicate that MSAFP screening is feasible, accurate and acceptable in a low-risk area.

Abortion, Spontaneous↗