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Biomedical subjects

J M Reynolds

Publications and source records attributed to J M Reynolds.

At least 37 records · Page 2Linked to original sources
PubMed1993

Psychosocial adjustment of adult survivors of a paediatric dialysis and transplant programme.

The social adjustment of 45 young adult renal patients who commenced treatment for end stage renal disease (ESRD) as children and of 48 age and sex matched controls were compared. Renal patients were less socially mature than controls. More lived with their parents, fewer had an intimate relationship outside the family, they had fewer school qualifications, and there was more unemployment among them. The majority, however, were in employment and the level of subjective stress and support derived from most of these areas was comparable in renal patients and in controls. Having a close relationship with a member of the opposite sex was the only domain in which renal patients reported more stress than controls. Early start of illness and current health problems were associated with poorer social outcome. A lifelong history of ESRD leads to suboptimal or delayed social functioning on conventional indicators. However this does not lead to increased overall distress in the patients about their social circumstances and quality of life does not appear to be substantially impaired.

Adaptation, Psychological↗
PubMed1993

Pharmacokinetics of 70-kilodalton fluorescein-dextran in experimental diabetes mellitus.

The pharmacokinetics of fluorescein-labeled dextran with a MW of 70,000 (FD-70) were studied after i.v. injection of single 5-mg/kg doses to control (C), untreated diabetic (D) and insulin-treated diabetic rats. Concentrations of FD-70 in serum, urine and various tissues were determined using a size exclusion chromatographic method. Untreated diabetes caused a striking change in the elimination parameters of FD-70, whereas the distribution parameters were mostly unaffected by the disease. The area under the serum concentration-time curve (microgram-hr/ml) in D rats (1360 +/- 506) was approximately 8 times that in C rats (175 +/- 16). Consistent with this, the terminal harmonic half-lives of FD-70 in D and C rats were 16.1 and 1.80 hr, respectively. Although the renal clearance of the macromolecule was similar in the two groups, the differences in the area under the serum concentration-time curve values could be accounted for by the substantially lower nonrenal clearance of FD-70 in D rats (0.0297 +/- 0.0296 vs. 0.434 +/- 0.050 ml/min/kg). At 12 hr after the administration of FD-70, concentrations of the macromolecule in the heart, lung, brain and kidneys were negligible. However, the C and D livers contained 53.3 +/- 11.2 and 14.0 +/- 6.8% of the administered dose at this time. Most of the diabetes effects on the disposition of FD-70 were reversed by chronic insulin treatment. It is concluded that the significant differences between D and C rats in their serum concentration-time profiles of FD-70 are likely due to differences in their liver accumulation of the macromolecule.

Animals↗
PubMed1991

Disposition of fluorescein-labelled dextran (150 kD) in isolated perfused livers from control and diabetic rats.

Isolated perfused livers were used to study the hepatic disposition of fluorescein-labelled dextran with a MW of 150 kD (FD-150), in control and streptozotocin-induced diabetic rats. A 100-microliter volume of FD-150 solution (10%, w/v) was injected as a rapid bolus dose into the inlet catheter of the isolated livers, and samples were collected from the outlet catheter in 2-sec intervals for 80 sec. Statistical moment theory was used to calculate the distribution and elimination parameters of the tracer based on the concentrations of FD-150 in the outflow. The values (mean +/- SD) of mean transit time, volume of distribution, and extraction ratio of FD-150 in the isolated livers from control rats were 16.3 +/- 2.00 sec, 0.298 +/- 0.054 ml/g liver, and 0.24, respectively. Similar values were obtained in diabetic livers, suggesting that streptozotocin-induced diabetes does not affect the hepatic disposition of FD-150.

Animals↗
PubMed1991

Changes in psychosocial adjustment after renal transplantation.

The psychological aspects of transplantation were studied in 29 children and adolescents with functioning renal transplants. Most parents rated their child's physical health as considerably improved after transplantation. They also noted improvements in the child's behaviour and in the quality of family life. When compared with a sample of children being treated by hospital haemodialysis, children who had received transplants had more favourable parental views of behavioural and emotional adjustment, better parental psychiatric adjustment, and indications of superior child rated mood, self concept, and social functioning. Children who had received transplants did, however, show an increase in minor behavioural symptoms compared with healthy controls, and most parents required continuing psychological and social support as well as attention to physical aspects of the child's condition. Kidney transplantation is associated with improved psychosocial behaviour in children, but there is a continuing need for support for parents in dealing with minor psychological problems after the transplant.

Adaptation, Psychological↗
PubMed1990

Psychosocial issues in children on hospital haemodialysis: nurses' views.

In a sample of 21 children and adolescents on hospital haemodialysis, nurses identified a substantial percentage of the children (about half) as having marked problems in psychological adjustment. Nearly half of the children were also regarded as showing poor compliance with aspects of treatment other than dialysis. More children were rated as disturbed by nursing than by research psychiatric assessments; there was limited congruence between nurses' and parent/child ratings of problems in physical well-being or in treatment compliance. The reasons for these discrepancies are explored. Our results highlight the importance that psychological aspects in the nursing of children with chronic renal failure on hospital haemodialysis are recognised.

Adolescent↗
PubMed1989

Early in reperfusion, leukocytes alter perfused coronary capillarity and vascular resistance.

Myocardial no-reflow is a critical consequence of myocardial ischemia-reperfusion (I/R). Recent studies indicate that formed blood elements (e.g., leukocytes and platelets) contribute greatly to the compromise of myocardial blood flow that occurs after I/R. To assess the contributions of leukocytes and platelets to alterations in microvascular perfusion, we measured total coronary vascular resistance and perfused coronary capillary density before and after a 30-min period of no-flow ischemia in isolated rat hearts perfused with either 1) a Krebs-albumin-red cell solution [K(2)RBC]; 2) diluted whole blood (DWB) with Krebs (1:1); or 3) leukocyte-free DWB (LFB). We found that hearts perfused with K(2)RBC before ischemia demonstrated a significant decrease in perfused capillarity (-25%, P less than 0.05) after 25 min of reperfusion. Hearts perfused with LFB before ischemia exhibited a similar decrease in perfused capillarity (-33%, P less than 0.05) during reperfusion. However, in the DWB-perfused hearts, there was a 62% decrease in perfused capillarity (-62%, P less than 0.01) during reperfusion. Moreover, during reperfusion, total coronary vascular resistance was elevated significantly (+76%, P less than 0.01) in the DWB-perfused hearts but not in either the K(2)RBC or LFB groups. These results indicate that 1) platelets do not play a major role in alterations of microvascular perfusion after ischemia; 2) leukocytes are not requisite for the development of microvascular no-reflow early in reperfusion but their presence further exacerbates this deleterious effect; and 3) a relationship exists between perfused capillarity and vascular resistance in the isolated rat heart after global ischemia.

Animals↗
PubMed1988

Psychiatric adjustment in children with chronic renal failure.

Problems in psychiatric adjustment were found to be more common in children and adolescents with chronic renal failure (22 subjects on hospital haemodialysis and 22 with less severe renal failure) than in healthy matched controls. There was a trend towards more definite and marked psychological difficulties in patients with more severe renal condition. However, the less severely physically ill children tended to have increased difficulties in school adjustment and they reported more feelings of loneliness. The findings have implications on the management of children with chronic renal failure.

Adaptation, Psychological↗
PubMed1988

How parents and families cope with chronic renal failure.

We studied the effects on the family of childhood chronic renal failure by contrasting children with varying degrees of severity of illness with healthy controls. Disruption of family life was most common in families with the more severely ill children (on hospital haemodialysis) and there was a tendency for more mental health problems in the parents in this group. Although more of these parents reported that the child's illness had had an impact on the marriage, marital break up was not related to illness status. There were indications that illness had resulted in an increase of subjective stress but also of support in a number of psychosocial areas for parents, especially those in the more severely affected group. Nevertheless at the time of assessment, fewer mothers in this group were deriving support from their social life and fewer fathers of ill children from their jobs or finances.

Adaptation, Psychological↗
PubMed1988

Subchronic oral administration of gossypol-acetic acid (GAA) alters the distribution and utilization of radioiron in male rats.

Gossypol-acetic acid (GAA) has been shown to be a powerful chelator of iron. To determine how subchronic administration of GAA affects the distribution and utilization of radioiron, male Holtzman rats, which had received a daily oral dose of GAA (20 mg/kg body weight) for 16 weeks, were injected i.p. with [59Fe]citrate (activity = 16.5 muCi/kg body weight) and [59Fe] incorporation into circulating erythrocytes, bone marrow, liver, spleen, skeletal muscle, and urine was measured 6, 12, or 24 h after [59Fe] administration. Iron [59Fe] incorporation was enhanced in the spleens, livers, bone marrow, and blood of the GAA-treated rats, and increased as the time post-[59Fe] injection increased. Hematological parameters remained within normal limits throughout the 16-week treatment period, suggesting an erythropoietic compensation in the GAA-treated rats. Iron status was markedly different in the GAA-treated rats at the end of the 16 week treatment period, suggesting altered iron utilization. The data suggest that [59Fe] is preferentially distributed to the erythroid tissues of GAA-treated rats for utilization in erythropoiesis.

Administration, Oral↗
PubMed1984

Using irreversible hydrocolloid to evaluate preparations and fabricate temporary immediate provisional restorations.

Two unique techniques that use irreversible hydrocolloid and an Omnivac matrix have been presented. The first technique is used to evaluate the adequacy and uniformity of the tooth preparation. The second technique is used to create a TIPR for the patient while the PIPR is being fabricated. The TIPR-PIPR system can be used to facilitate proper diagnosis, planning, and treatment; and it results in improved patient comfort, dentist efficiency, and increased control over the final restoration.

Colloids↗
PubMed1983

The concentration of sodium, potassium and chloride in rabbit submandibular saliva during postnatal development.

Saliva was collected from the cannulated ducts of submandibular glands of rabbits at various ages from birth to adulthood and analysed for sodium, potassium and chloride. Saliva was obtained at all ages by electrical stimulation of the parasympathetic innervation to the gland. On the day of birth (day 1), salivary sodium was 108.5 +/- 3.4 mM (n = 8) and chloride was 89.9 +/- 3.6 mM (n = 9) falling to adult-like concentrations of 5.7 +/- 0.6 mM (n = 13) and 16.5 +/- 1.2 mM (n = 9) respectively by day 10. On Day 1, salivary potassium was 23.9 +/- 1.8 mM (n = 7) and rose progressively to 76.8 +/- 2.5 mM (n = 8) on day 17. Adult potassium concentration was 30-40 mM. A wide range of flows was obtained at all ages and at each age sodium and chloride concentrations were approximately constant at all flows. Therefore the changes in electrolyte concentration cannot be explained by differences in flow. The results suggest a maturation of ductal transport of sodium, potassium and chloride ions concurrent with the structural maturation of striated duct cells.

Animals↗
PubMed1979

A seasonal comparison of parathion degradation on oranges in Arizona.

A study comparing the leaf residue decay of parathion wettable powder (8 lbs per acre) on oranges was carried out on neighboring plots in Arizona beginning in October, 1975, and February, 1976. While identical amounts of parathion were present immediately after spraying and the half-life of parathion was the same in both months, there was, on the average, more parathion residue during February. Graphs of parathion and paraoxon levels over time differed between months (in excess of sampling variability). This most likely was due to the daily influences of climatological variables which were obviously different in October and February.

Arizona↗
PubMed1979

Studies of the development of brain barrier systems to lipid insoluble molecules in fetal sheep.

1. The development of the blood-brain and blood-c.s.f barriers to lipid insoluble substances of different molecular radii has been studied in fetal sheep, early (60 days) and late (125 days) in gestation, using labelled erythritol (C14), sucrose (3H or 14C), inulin (3H or 14C) and albumin (125I), or albumin and IgG detected by immunoassay. 2. Morphological studies of fetal brain and choroid plexus at the same gestational stages were carried out using thin section electron microscopy and the freeze fracture techniques. 3. Penetration of markers into c.s.f. was substantially greater at 60 days than at 125 days, but at both ages the steady-state level achieved appeared to be related to molecular size. 4. A simple model describing penetration from blood into c.s.f. at 60 days is proposed. It involves the assumption that c.s.f. and brain extracellular fluid are effectively separate compartments; morphological and permeability data which supports this assumption is presented. The data for c.s.f. at 60 days are consistent with the suggestion that the markers penetrate into c.s.f. by diffusion and are not restricted by small pores in the interface between blood and c.s.f. 5. The reduction in penetration which occurred by 125 days for all markers except erythritol appears to be accounted for by an increase in the sink effect and a decrease in the effective surface area for exchange between blood and c.s.f. 6. Intercellular tight junctions of both cerebral endothelial cells and choroid plexus epithelial cells were well formed at 60 days gestation. There was no change in junctional characteristics previously thought to correlate with transepithelial permeability (tight junction depth and strand number) between the two ages studied, although there were marked changes in permeability. 7. Evidence is advanced in support of the hypothesis that in the fetus much of the penetration of lipid insoluble non-polar substances across the blood-c.s.f. barrier and perhaps across the blood-brain barrier occurs via a transcellular route consisting of a system of tubulo-cisternal endoplasmic reticulum. Penetration via the choroid plexus appears to be the dominant route for penetration from blood into c.s.f. in the 60 day fetus.

Animals↗