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Biomedical subjects

D Price

Publications and source records attributed to D Price.

At least 109 records · Page 6Linked to original sources
PubMed1993

Quantification of tissue plasma volume in the rat by contrast-enhanced magnetic resonance imaging.

Magnetic resonance imaging enhanced with a macromolecular contrast medium (MMCM), albumin-Gd-DTPA, was used to estimate the plasma volume in vivo in the myocardium, lung, liver, and skeletal muscle of 10 normal rats. The plasma volumes of the same tissues in a parallel group of six rats were estimated in vitro by a conventional radioisotopic technique (111In-transferrin). Plasma volumes of myocardium, lung, liver, and skeletal muscle estimated by the MR technique (microliter plasma cc-1 of tissue) were 101, 109, 163, and 11.0, respectively, while plasma volumes measured by the 111In-transferrin radioisotope technique (mg plasma g-1 of tissue) were 78.6, 215, 143, and 11.2, respectively. Assuming a ratio of densities of aerated lung to blood of 0.45 and of other tissues to blood of 1.0, correlation between the methods was excellent (R2 = 0.99) indicating that MR imaging enhanced with MMCM permits reliable in vivo estimation of tissue plasma volume in the rat.

Albumins↗
PubMed1993

The impact of spina bifida on the medical services of Newfoundland and Labrador.

This institution receives all live spina bifida patients from Newfoundland and Labrador. The aim of this study is to determine the outcome of these patients and the impact on the medical system. On a retrospective chart review, 274 patients born between 1967 and 1990 were studied. An analysis of the statistical variables showed that the incidence per 1,000 live births has remained stationary in Newfoundland and Labrador; there is a slight female predominance; 64% were born to young mothers and the peak incidence occurred in March, April, and May. A total of 179 patients of 254 who underwent surgery were alive and underwent rehabilitation programmes. Only 35% are wheelchair bound; the rest are ambulatory. One hundred sixty-one are of school age or older, 78 are in regular high school (3 dropouts), 36 are in special education, 6 graduated from high school, 4 are in university, 15 had no neurological deficit, 7 were lost in follow-up, 5 died, 9 had gross mental retardation, and 1 is the mother of three normal children. To attain these results these patients had multiple admissions and surgical procedures and the patients are seen twice a year in a rehabilitation and multidisciplinary clinic. From this study, the utilization of the medical services and impact on the community is great. However, the majority of these patients appear to attain a surprisingly high quality of life.

Female↗
PubMed1993

Positive and negative regulatory elements of the rabbit embryonic epsilon-globin gene revealed by an improved multiple alignment program and functional analysis.

The epsilon-globin genes of mammals are expressed in early embryos, but are silenced during fetal and adult erythropoiesis. As a guide to defining the regulatory elements involved in this developmental switch, we have searched the sequences of epsilon-globin genes from different mammals for highly conserved segments. The search was facilitated by the development of a new program, called yama, to generate a multiple alignment of very long sequences using an improved scoring scheme. This allowed us to generate a multiple alignment of sequences from a more divergent group than previously analyzed, as demonstrated here for representatives of four mammalian orders. In parallel experiments, we constructed a series of deletion mutations in the 5' flank of the rabbit epsilon-globin gene and tested their effect on an epsilon-globin-luciferase hybrid reporter gene. These results show that 121 bp of 5' flank, containing CACC, CCAAT and ATA motifs, is sufficient for expression in erythroid K562 cells. Both positive and negative cis-acting control sequences are located between 218 and 394 bp 5' to the cap site, in a region previously proposed to be a silencer. The positive regulatory sequence contains conserved binding sites for the nuclear protein YY1 adjacent to another highly conserved sequence. The negative element contains a conserved sequence followed by a purine-rich segment. This analysis maps the upstream control sequences more precisely and points to a very complex regulatory scheme for this gene.

Animals↗
PubMed1992

Interferon modulation of 5-fluorouracil: use in neoadjuvant therapy inhibits experimental liver metastases in nude mice.

Experimental liver metastasis was studied in 4-5 week old athymic nude mice that were injected intrasplenically with a human colorectal tumor cell line (LoVo). A treatment schedule combining 5-fluorouracil and interferon (IFN) was previously shown to inhibit liver metastases. When this treatment was delayed until after splenectomy at 1, 2 and 3 weeks after tumor cell injections, liver metastases were not inhibited. However, when IFN was given during the interval between tumor cell injections and splenectomy (as neoadjuvant therapy), liver metastases were inhibited in the 2 and 3 week groups, but not in the 1 week group.

Animals↗
PubMed1991

Tonic and phasic orientation in full-term and preterm infants.

Thirty-three full-term infants and thirty-eight preterm infants (on average born at 30 weeks gestation) were tested for their latency to turn toward checkered stimulus patterns (phasic orienting or "attention-getting") and for the duration of their initial fixation (tonic orienting or "attention-holding"). Plotted against the logarithm of the subjects' postconceptional age, turning latency fell linearly between 36 and 120 weeks, while fixation time fell abruptly at 53 weeks. Preterm and full-term infants showed the same developmental trends, implying that both of these attentional behaviors are biologically timetabled and that neither is greatly affected by premature extrauterine experience. Unexpectedly, phasic orientation in the first 30 postnatal days was significantly faster in preterm than in full-term infants, and fixation times failed to differ. Despite the necessary functional integration of phasic and tonic orienting in mature visual scanning and attention, the present results suggest an independence in their early postnatal development and that neither is mature at birth.

Arousal↗
PubMed1991

Tumour localisation with a radioactively labelled reshaped human monoclonal antibody.

A genetically reshaped human IgG1 monoclonal antibody (Hu2PLAP) with anti-tumour specificity, was radiolabelled with Indium-111 by chelation with a new macrocyclic compound (DOTA) which allows the production of stable radioimmunoconjugates for in vivo application. This was used to image seven patients with malignant disease, of whom two had been previously exposed to mouse monoclonal antibodies and had developed human anti-mouse antibodies (HAMA). Successful tumour localisation was seen in the four patients with active disease and antigen positive tumours. No patient showed any antibody responses against Hu2PLAP, but three out of six patients tested showed an immune response against the macrocycle DOTA. Reshaped human monoclonal antibodies with anti-tumour specificity may facilitate repeated administrations of radioactive antibodies, thus allowing new possibilities, both in the diagnosis and treatment of cancer.

Adult↗
PubMed1990

The Rett syndrome: progress report on studies at the Kennedy Institute.

Clinical, biochemical and pathological studies in patients with the Rett syndrome (RS) are presented. The neuropathological changes and alterations in neurotransmitter markers are particularly interesting and provide valuable information that may be helpful in understanding the behavior and neurological phenotype of RS.

Adolescent↗
PubMed1990

Release of peptide cotransmitters from a cholinergic motor neuron under physiological conditions.

In previous studies, we demonstrated that B15, one of the two cholinergic motor neurons of the accessory radula closer muscle of Aplysia, synthesizes two peptides, small cardioactive peptides A and B (SCPA and SCPB), that, when exogenously applied, increase the size and relaxation rate of muscle contractions elicited by motor neuron stimulation. In the present experiments, we obtained evidence that the SCPs are released under physiological conditions. Specifically, we characterized firing patterns of motor neuron B15 during normal behavior, simulated them in vitro, and demonstrated that this type of neuronal activity produces decreases in SCP levels in neuronal processes and terminals. We also obtained evidence that suggests that enough SCP is released under physiological conditions to modulate neuromuscular activity in the accessory radula closer. We demonstrated that physiological activity of neuron B15 produces significant increases in muscle cAMP levels. Furthermore, increases in the size and relaxation rate of muscle contractions can be produced by changes in stimulation parameters that are also likely to maximize effects of released endogenous SCPA and SCPB.

Animals↗
PubMed1990

Epidemiology of shingles.

One thousand and nineteen patients with acute varicella zoster viral infection were referred to the physiotherapy department for treatment between 1978 and 1986. Sixty per cent were women and 40% were men with a mean age of 58 years (range 9-96 years). The prevalence varied between 1.3 and 1.6 per 1000 per annum. The left side was affected in 52% while the right was affected in 48%. The thoracic dermatomes were the most commonly affected (56%) followed by cervical (17%), lumbar (10%), sacral (5%), and the trigeminal nerve was infected in 12%. There was a significant seasonal (P less than 0.001) variation in the prevalence of acute varicella zoster virus infection, most common in the summer and least common in the spring. There was no clustering in time and space so that it is unlikely that the varicella zoster virus is infective or that re-exposure to the virus causes reactivation of the latent virus.

Adolescent↗
PubMed1989

Neuropathological changes in early HIV-1 dementia.

Early pathological abnormalities in human immunodeficiency virus (HIV-1)-related dementia have not been well documented. We report a homosexual man with fatigue and intermittent diarrhea in whom early HIV-1-related dementia was demonstrated during neurological screening in the Multicenter AIDS Cohort Study. Within 4 months he died of massive epistaxis, and the brain revealed astrocytosis of white matter and mild pallor of myelin staining in the absence of inflammation, multinucleated giant cells, and brain atrophy.

AIDS Dementia Complex↗
PubMed1989

Diagnosis and incidence of cardiac injury in children with blunt thoracic trauma.

Over a 20-month period, we prospectively studied 41 children with blunt thoracic trauma (BTT) to determine the incidence and morbidity of cardiac injury in this population. Four patients died, and the data were incomplete in 10, leaving 27 for analysis. Serial electrocardiograms (ECG) were abnormal in 36% of the patients studied, serial creatine phosphokinase isoenzyme (CK-MB) ratios were elevated in 31%, echocardiogram showed septal dysfunction in 14%, and pyrophosphate scan showed grade 1 uptake in 14%. There was poor correlation among tests, since only four patients had more than one abnormal test. There was no significant difference in Injury Severity Score or Thoracic Abbreviated Injury Scale between patients with and without abnormal investigations. No patient in the study developed arrhythmias or cardiac failure. In 13 trauma-related deaths undergoing autopsy over the same period, including the four with thoracic trauma, none had evidence of cardiac injury. These results indicate a striking lack of consistency in the diagnosis of posttraumatic cardiac injury in children using standard investigations. The absence of adverse cardiac events in surviving patients and the lack of autopsy evidence of cardiac injury in the trauma deaths suggest that the actual incidence and clinical significance of these lesions in children is lower than generally reported. Children with BTT should be followed clinically, and reliance on screening tests should be avoided.

Adolescent↗
PubMed1989

Ergometrine and 5-hydroxytryptamine binding sites in rat brain and myometrium.

Functional studies suggest that ergometrine is a partial agonist involving 5-hydroxytryptamine (5-HT) receptors in rat uterus. Ergometrine displaced [3H]5-HT from specific binding sites in rat brain, but did not displace [3H]5-HT at functionally important concentrations in rat myometrium. These binding studies indicate that the agonist and antagonist actions of ergometrine in rat uterus arise from its initial interaction with binding sites other than those for 5-HT.

Animals↗