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Biomedical subjects

R Ford

Publications and source records attributed to R Ford.

At least 109 records · Page 6Linked to original sources
PubMed1992

From the jumping Frenchmen of Maine to post-traumatic stress disorder: the startle response in neuropsychiatry.

The startle response is a universal and phylogenetically ancient reflex. Pathological exaggerations and modifications of startle underlie the symptomatology of a surprisingly diverse range of neuropsychiatric disorders, a fact that seems to have gone largely unappreciated. We review the available literature on the physiology of the normal human startle response and examine the neuropsychiatric conditions characterized by pathological startle. Startle epilepsy and primary hyperekplexia are considered as neurological disorders involving abnormal startle. Patients with hyperstartle and exotic culture-bound syndromes characterized by excessive startle are considered by the authors to represent extreme variants of the normal startle response. Post-traumatic stress disorder, drug and alcohol withdrawal states and schizophrenia all have abnormal startle as a clinical feature secondary to increased arousal and presumed disturbance of central neurotransmitter systems. The neurophysiological mechanisms by which abnormalities of the startle response may occur are discussed and a system of classification of neuropsychiatric hyperstartles is suggested.

Humans↗
PubMed1990

Uterine cervical punch biopsy specimens can be analyzed by 1H MRS.

Biopsy specimens of the uterine cervix, including colposcopically directed punch biopsy specimens of females with atypical Papanicolaou smear tests, are suitable for analysis by magnetic resonance (MR) spectroscopy. A narrow lined lipid MR spectrum, characteristic of malignant tissue, is obtained from a 6-mm3 biopsy specimen of histologically confirmed squamous carcinoma of the cervix. In contrast, specimens containing inflammatory cells generate a broad component only centered at 1.3 ppm with a T2 relaxation value of less than 350 ms. Most biopsy specimens which contain dysplastic cells or evidence of human papilloma virus (HPV) infection have a discernible lipid spectrum similar to that of the malignant tissue specimen. Long T2 relaxation values found in malignant tissue specimens at 1.3 and 1.2 ppm are observed in some but not all of the biopsies which show evidence of HPV infection. The suitability of small tissue samples, such as punch biopsy specimens, for study by MR illustrates the sensitivity of this technique and its potential as an aid to histopathological discrimination between the various precursor states of cervical cancer.

Biopsy↗
PubMed1990

Bone marrow transplant. Recent advances and nursing implications.

The myriad therapies used during bone marrow transplantation are in constant flux. Major problems still need to be solved including relapse after transplant and graft rejection. More effective and less toxic conditioning regimens, acceleration of hematopoietic and immune reconstruction, and improved control of GVHD and infections are currently being studied. Nurses are vital in orchestrating the complicated care these therapies mandate as well as providing emotional support to patients and their families. Nursing research is being conducted in many areas of marrow transplantation. Quality-of-life and survivor issues have been identified as priorities by many nurses working in this field. Nurses will continue to play a pivotal role in caring for patients as marrow transplantation continues to evolve as a major form of cancer treatment.

Bone Marrow Transplantation↗
PubMed1990

Continuous multiple location body temperature measurement of infants.

This study was done to evaluate the most suitable location of skin temperature sensors to enable long term temperature measurements of infants. A high accuracy eight channel temperature monitor was developed. Linear semiconductor sensor probes were constructed in association with this. System accuracy and stability were tested. Preliminary clinical studies have shown considerable variation from the core temperature for all surface measurement locations.

Body Temperature↗
PubMed1990

Computer polygraphic system for infants at risk for sudden infant death syndrome (SIDS).

We have designed and developed a suite of equipment for polygraphic assessment of infants thought to be at risk for Sudden Infant Death Syndrome. A range of commercially available and custom made instrumentation is used to monitor cardio-respiratory function and thermal activity. The PC based system records continuous overnight trends and is able to detect apnoea, bradycardia, tachycardia, oxygen desaturation and other significant clinical events, producing summary data and graphs at the conclusion of the monitoring. The system is fully interactive and adaptable to various clinical and research requirements.

Computer Graphics↗
PubMed1989

Summary of complementation groups of UV-sensitive CHO cell mutants isolated by large-scale screening.

A summary is given for the lineage and complementation group assignments of 153 UV-sensitive mutants of the CHO AA8 cell line. The distribution of mutants among six complementation groups was highly non-random, with the great majority of the isolates belonging to groups 1 and 2. This asymmetry is consistent with the known hemizygosity of these two linked loci in CHO cells. The relative numbers of mutants induced in group 2 was found to depend greatly on the type of mutagen used. Mutagenesis with UV radiation, ethyl methanesulfonate (EMS), N-methyl-N'-nitro-N-nitrosoguanidine and 7-bromomethylbenz[a]anthracene produced high frequencies of group 2 mutants. In contrast, ICR170 and ICR191, which are thought to produce mostly frameshift mutations, yielded very few mutants in group 2. These results are of particular importance in light of the recent finding that the human ERCC2 gene, which corrects group 2 mutants, has very strong homology with the yeast gene RAD3. RAD3 is an essential gene for viability in yeast, and the low recovery of group 2 mutants using the frameshift agents strongly suggests that frameshift mutations tend to be lethal in the hamster ERCC2 locus. Several mutagen-sensitive double mutants were isolated in two-step selections from EMS-, mitomycin C- or UV-sensitive parental cells, including the line UVU1, the first mammalian line with two mutations that affect UV sensitivity. The first mutation inactivated excision repair, and the second mutation appears to have affected some other recovery process. UVU1 should be useful for studying recovery processes that are separate from nucleotide excision repair.

Animals↗
PubMed1988

Characterization of receptors for a T cell derived cytosolic BCGF-60kD.

A 60 kD cytosolic protein derived from human peripheral blood T cells has been shown to mediate proliferation in BCGF responsive long term B cell cultures. In this report, we show cBCGF-60kD can be radioiodinated with no significant loss of biologic activity and bound specifically to B cell surface membrane receptors. The time course of 125I-cBCGF-60kD demonstrated that binding reached saturation within 40 minutes, (T 1/2 of 15 minutes). Scatchard analyses of ligand-receptor binding identified a high affinity receptor (0.6(-3) x 10(3) receptors per cell) having a dissociation constant of 1-8 pM. Partial cross-competition experiments with a secreted, T cell derived BCGF-12kD identified a potential receptor heterogeneity on BCGF responsive B cell line.

B-Lymphocytes↗
PubMed1987

Bacterial chemotaxis. Cell flux model, parameter measurement, population dynamics, and genetic manipulation.

In this paper, we summarized our recent efforts toward accomplishing four key goals important for control of microbial population dynamics in nonmixed systems: (1) derivation of a cell population flux model based on individual cell properties; (2) measurement of the population random motility and chemotaxis parameters appearing in this model using a simple experimental assay; (3) quantitative understanding of the effects of cell motility and chemotaxis properties on microbial population dynamics; and (4) manipulation of chemotactic responses by genetic modification.

Bacteria↗
PubMed1986

A behavioral role for enkephalins in regulating locomotor activity in the insect Leucophaea maderae: evidence for high affinity kappa-like opioid binding sites.

D'-Ala-2 met-5-enkephalinamide application to the cerebral ganglia of Leucophaea maderae results in a decrease in locomotor activity. The opiate antagonist, naloxone, can block this effect as well as the depressant effect of morphine on locomotor activity. D-Ala-2,leu-5-enkephalinamide and dynorphin enhance locomotor activity following their topical application to the cerebral ganglia. This effect also can be antagonized by concomitant naloxone treatment. Benzomorphans were the most potent ligands tested in their ability to displace [3H]D'-ala-2,met-5-enkephalinamide whereas mu and delta ligands were by comparison less potent. These results suggest the presence of kappa-like opioid receptors in Leucophaea cerebral ganglia. The kappa ligands also are potent in enhancing locomotor activity in addition to being weakly antagonized by naloxone. Again, these results indicate the presence of multiple-opiate receptor types in invertebrates.

Animals↗
PubMed1986

Hind-limb vascular responses in anaesthetized dogs to aortic root injections of veratridine.

In dogs anaesthetized with chloralose we determined the reflex responses of the blood vessels in the vascularly isolated hind limb to injection of veratridine into the aortic root. The presence of a cannula tied in the ascending aorta ensured that responses were due to stimulation of nerves only in the region perfused by the coronary arteries. Injections of veratridine resulted in transient decreases in vascular resistance and in venous resistance in a perfused cutaneous vein. The responses were reduced when carotid perfusion pressure was elevated. The afferent pathway for the reflex lay in the vagus nerves and the efferent pathway to the limb was in the sciatic and femoral nerves, but the vasodilatation was shown to be predominantly non-cholinergic.

Anesthesia, General↗
PubMed1986

Effect of veratridine injected into the aortic root on resistance and capacitance in the abdominal circulation in anaesthetized dogs.

In dogs anaesthetized with chloralose, cardiac receptors were stimulated by injections of veratridine into the aortic root and the effects studied on resistance and capacitance in the vascularly isolated and perfused abdominal circulation. Unless carotid sinus pressure was high, veratridine injections consistently resulted in dilatation of resistance and capacitance vessels. However, at high carotid pressures, the resistance response to veratridine was inhibited and the capacitance response was usually reversed. These results indicate that stimulation of cardiac receptors can affect resistance and capacitance in the abdominal circulation. Further experiments are required to evaluate the physiological role of these responses.

Abdomen↗
PubMed1985

Abdominal vascular responses to changes in carbon dioxide tension in the cephalic circulation of anaesthetized dogs.

Dogs were anaesthetized with chloralose, the regions of both carotid sinuses were vascularly isolated and perfused with arterial blood and both cervical vagosympathetic trunks were cut above the nodose ganglia. The cephalic circulation was perfused through the brachiocephalic and left subclavian arteries with blood which was equilibrated with various levels of CO2. The abdomen was vascularly isolated, perfused through the aorta at constant flow and drained through the inferior vena cava at constant pressure. Changes in vascular resistance were determined from changes in abdominal aortic perfusion pressure and changes in capacitance from the integral of the changes in venous outflow. An increase in PCO2 in the cephalic perfusate resulted in an increase in abdominal vascular resistance and a decrease in capacitance. However, when carotid sinus pressure was high, the response of resistance to an increase in cephalic PCO2 was abolished and that of capacitance was significantly reduced. The reflex responses of both vascular resistance and capacitance to a change in carotid sinus pressure were enhanced when the cephalic PCO2 was raised. However, the effect on the reflex capacitance response from stimulation of baroreceptors was obtained only when PCO2 was changed below 5 kPa whereas the effect on resistance occurred at higher values of PCO2. The interaction between the effects of changes in cephalic PCO2 and the carotid sinus reflex and the differential effect on resistance and capacitance vessels have been explained in terms of the known difference in the sensitivities of these vessels to sympathetic nerve activity.

Abdomen↗
PubMed1983

Veno-occlusive disease following marrow transplantation.

Veno-occlusive disease is a newly identifiable complication after marrow transplantation that demands further research into its treatment and etiology. Nurses play a key role in the early detection as well as the continual physical and psychologic support needed by the patient throughout the course of this disease.

Ascites↗