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Biomedical subjects

T M Robinson

Publications and source records attributed to T M Robinson.

15 recordsLinked to original sources
PubMed1995

Blockade of digestion by famotidine pretreatment does not interfere with the opioid-enhancing effect of ingested amniotic fluid.

Ingestion of placenta or amniotic fluid by rats has been shown to enhance ongoing opioid-mediated antinociception, but does not, by itself, produce antinociception. This enhancement is produced by an active substance(s) in placenta and amniotic fluid that we have termed POEF for placental opioid-enhancing factor. Previous research has shown that enhancement requires mediation by the gastrointestinal system: gastric vagotomy blocks enhancement produced by ingested placenta; amniotic fluid injected SC or IP does not produce enhancement. The present study was designed to distinguish between two possible explanations for the blockade of the POEF effect produced by gastric vagotomy: that afferent information arising in vagal gastric receptors conveys the critical information to the CNS, or that disruption of vagal efferent action on digestion blocks the manufacture or activation of the POEF molecule in the gut. Famotidine is an H2-histamine receptor antagonist that reduces gastric acid and pepsin secretion to an extent at least as great as gastric vagotomy. Rats treated with either famotidine or a vehicle were fed placenta or a control substance, then stimulated with vaginal/cervical probing to produce antinociception that is partly opioid mediated. Famotidine did not block POEF enhancement of vaginal/cervical stimulation-induced analgesia in a tail flick latency test. These results suggest that enhancement by POEF does not require normal digestive processes or other processes inhibited by famotidine.

Amniotic Fluid↗
PubMed1995

A transputer-based physiological signal processing system. Part 1--System design.

This paper, the first of two, details the design and in-vitro testing of a transputer-based physiological signal processing system. The heart of the system is a transputer-based digital signal processing (DSP) board which can act as a stand-alone spectrum analyser, designed to operate in the audio-frequency band up to 25 kHz. The board comprises a T800 processor, two A100 transversal filters, 12 bit A-D circuitry capable of sampling up to 48 kHz, memory and address mapper. The initial application of the system is for the detection of early arterial disease. For this the DSP board is harnessed to the front end of a multigate pulsed Doppler ultrasound scanner operating at 4.8 MHz insonation frequency and incorporating a vessel wall tracking unit. The complete system performs a Fourier transform on the backscattered signals, providing spectral information on discrete areas of flow (0.6 mm3) across the vessel lumen in real time. This first paper describes the hardware, and the second describes the performance testing of the system on the bench and an assessment of its ability to detect low grade stenoses during steady flow.

Arteries↗
PubMed1995

Automated large-core needle biopsy of surgically removed breast lesions: comparison of samples obtained with 14-, 16-, and 18-gauge needles.

PURPOSE: To determine the needle size that would consistently enable the pathologist to correctly diagnose tissue core biopsy specimens. MATERIALS AND METHODS: Fifty-seven surgically removed mass lesions of the breast were sampled with a short-throw automated biopsy gun and an 18-gauge needle first, followed by a 16- and a 14-gauge needle. Samples were evaluated independently by three pathologists, and findings were compared with the final diagnosis made at surgical excision biopsy. RESULTS: The sensitivity for the diagnosis of all 26 malignant lesions was 100%, 92%, and 65% for biopsy samples obtained with 14-, 16-, and 18-gauge needles, respectively. Specificity for malignancy was 100% for all three needle sizes. All of the benign diseases were correctly diagnosed in samples obtained with all three size needles except for two samples that did not survive processing. CONCLUSION: Biopsy samples obtained with a 14-gauge needle provide the most accurate diagnosis, which correlates with the diagnosis made with the surgical excision biopsy technique.

Automation↗
PubMed1993

Effect of extracorporeal membrane oxygenation on platelets in newborns.

OBJECTIVES: To examine the effect of extracorporeal membrane oxygenation (ECMO) therapy on platelet function and number and to determine the in vivo survival of transfused platelets during ECMO. DESIGN: Prospective study of all neonates treated with ECMO during a 6-month period. SETTING: Neonatal intensive care unit in a tertiary referral center. PATIENTS: Ten infants, < 1 wk of age, with respiratory failure requiring ECMO. INTERVENTIONS: None. MEASUREMENTS: Platelet counts were measured at timed intervals to determine the effect of ECMO on platelet counts. The change in platelet counts after transfusion was also measured. Whole blood platelet aggregation studies were performed to determine the effect of ECMO on platelet function. MAIN RESULTS: A mean decrease of 26% from the baseline platelet count was found 15 mins after the initiation of ECMO, with an additional mean decrease of 16% by the end of 1 hr (p < .05). Fifteen minutes after platelet transfusions, a 17% mean increase in platelet counts was measured (p < .05). One hour after platelet transfusion, the platelet count had decreased to pretransfusion values. Platelet aggregation studies 15 mins after starting ECMO showed a 46% mean decrease in the response to collagen from baseline (p > .05), and a significantly (p < .05) reduced response to ristocetin and to adenosine 5'-diphosphate. Platelet adenosine triphosphate release was also significantly reduced. Single-unit platelet transfusions failed to correct platelet aggregation abnormalities. Resolution of platelet aggregation abnormalities and normalization of platelet counts occurred 8 hrs off ECMO. CONCLUSIONS: The results of these studies show that qualitative and quantitative platelet changes occur while a neonate is receiving ECMO. The survival rate of transfused platelets is reduced, and the acquired platelet dysfunction is not reversed by the transfusion of platelets with normal function while the patient is receiving ECMO.

Adenosine Triphosphate↗