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Biomedical subjects

M Lawson

Publications and source records attributed to M Lawson.

At least 91 records · Page 5Linked to original sources
PubMed1989

Comparison of chlortenoxicam and indomethacin on frusemide-induced diuresis.

A single oral dose of chlortenoxicam 4 mg, a new non-steroidal anti-inflammatory drug, significantly antagonized the diuretic and natriuretic actions of frusemide when compared with placebo in normal human volunteers. Indomethacin 50 mg significantly reduced the natriuretic, but not diuretic action of frusemide.

Adult↗
PubMed1987

How many electrocardiographic leads are required for exercise treadmill tests?

Forty-four consecutive patients who had perfusion defects on thallium-201 scanning and positive exercise treadmill tests were prospectively studied. Thirty-eight (86%) subjects had diagnostic ST segment changes in lead V5, 37 (84%) in lead V4, and 44 (100%) in either lead V4, V5 or both. Thirty patients had ST segment changes in the inferior leads, 20 in lead aVR, and only four in lead I and/or aVL. All of these latter subjects had diagnostic ST segments in lead V4 and/or V5. It is concluded that: combined electrocardiographic leads V4 and V5 detect the vast majority of ischemic changes during exercise treadmill testing, regardless of the site of perfusion defects detected by thallium-201 scanning; and monitoring the inferior and lateral leads rarely provides more diagnostic information.

Coronary Disease↗
PubMed1987

Local infusion of urokinase for the lysis of thrombosis associated with permanent central venous catheters in cancer patients.

We assessed the efficacy of local fibrinolytic therapy in 35 axillary-subclavian vein thromboses (SVT) that occurred in cancer patients with percutaneous central venous catheters (CVC). These catheters were indwelling for a median of 1 month (range, one day to 10 months) before thrombosis developed. Urokinase was administered at a dose of 500 to 2,000 U/kg/h. Complete lysis occurred in 25 of 30 thrombi that were directly infused, after a median of four days. Complete lysis occurred in one of 12 thrombi that could not be directly infused with urokinase and in two of six with associated phlebitis. Eighty-one percent of the thrombi that were symptomatic for less than 1 week before treatment resolved, compared with 56% present for longer than 1 week. Sixteen patients who had complete (12) or partial (four) thrombolysis did not have their CVCs removed. All four patients with partial thrombolysis had recurrent thrombosis at a median of eight days (range, one to 90). Only two patients who had complete thrombolysis had recurrent thrombosis, at 8 and 16 months. Only minor hemorrhagic toxicity was seen.

Adult↗
PubMed1986

Effect of 5-aminosalicylic acid (5-ASA) and other salicylates on short-chain fat metabolism in the colonic mucosa. Pharmacological implications for ulcerative colitis.

5-Aminosalicylic acid (5-ASA) suppressed nitrite-stimulated oxidation of the fatty acid n-butyrate in a dose-dependent manner in isolated human and rat colonic epithelial cells. 4-ASA had one-sixth of the capacity of 5-ASA and sulphapyridine (SP) little of the capacity of 5-ASA to suppress fatty acid oxidation in human colonic epithelial cells. Sulphasalazine (SASP), azodisalicylic acid (ADS), acetyl-5-ASA and acetyl salicylic acid (ASA) did not suppress fatty acid oxidation in rat colonocytes. The suppression index of fatty acid oxidation (SIFO) of respective salicylic acids correlated with the reported clinical effectiveness of each drug against ulcerative colitis (UC). The capacity of 5-ASA to affect nitrite-stimulated oxidation of fat in the colonic mucosa suggests that nitrite ions and control of fatty acid oxidation play a central role in the development and therapy of active UC.

Aminosalicylic Acids↗
PubMed1985

Student situation.

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Education, Nursing↗
PubMed1985

Gastrointestinal transit time in human pregnancy: prolongation in the second and third trimesters followed by postpartum normalization.

Fifty-nine studies of gastrointestinal transit time were performed in 27 healthy women during pregnancy and postpartum. Gastrointestinal transit time was defined as the time of the first sustained rise in breath hydrogen concentration after ingestion of 10 g of lactulose. Gastrointestinal transit time was significantly prolonged in both the second and third trimesters of pregnancy (125 +/- 48 min and 137 +/- 58 min, respectively) when compared with either the first trimester of pregnancy or the postpartum period (99 +/- 39 min and 75 +/- 33 min, respectively). Transit times measured in the first trimester were not significantly different from those postpartum. Because the prolongation of transit time in late pregnancy is transient, it is probably due to hormones (perhaps progesterone) or other metabolic effects of pregnancy.

Adolescent↗
PubMed1985

Evaluation of silicone elastomer catheters for long-term intravenous chemotherapy.

We evaluated the efficacy and the complications of 65 silicone elastomer catheters inserted percutaneously for long-term venous access for administration of chemotherapy, antibiotics, and blood products in patients with metastatic cancer. Treatments were administered either in the hospital or in the outpatient clinic, using a portable infusion pump. The median indwelling time of catheters was 238 days (range, two to 521). The projected duration of catheter function, when the electively removed catheters were censured, was 310 days. Twenty-three catheters were removed because of malfunction, while the remaining either were discontinued electively (20) or were functioning at the conclusion of the study (22). The problems necessitating removal of 23 catheters were inadvertent dislodgement from loose sutures (eight), mechanical damage to the catheters (four), sepsis (four), phlebitis (four), intraluminal blockage with a clot (two), and cellulitis (one). We conclude that silicone elastomer catheters are safe and reliable for extended venous access for cancer chemotherapy. They are easy to insert and remove and can be replaced with a guide wire without requiring surgical intervention.

Antineoplastic Agents↗
PubMed1983

Coordination of gastric and gallbladder emptying after ingestion of a regular meal.

The relationship of gallbladder emptying and refilling to gastric emptying of solids, gastrointestinal transit time, and human pancreatic polypeptide response was examined after ingestion of a standard breakfast (40% fat) in 12 healthy men and women. Gallbladder volume, emptying, and refilling was measured by real-time ultrasonography, and gastric emptying of solids was measured scintigraphically by the disappearance from the stomach of egg labeled with 99mTc-sulfur colloid. Gastrointestinal transit time was defined as the time of initial rise in breath hydrogen following ingestion of 10 g of lactulose. Serum human pancreatic polypeptide level was measured by radioimmunoassay. Gallbladder emptying was biphasic, initially 0.015 +/- 0.003 min-1 and later 0.005 +/- 0.001 min-1, and gallbladder volume remained small until refilling began at 249 +/- 67 min. Gallbladder refilling was 70% complete at 335 +/- 57 min. The slower rate of gallbladder emptying and tonic gallbladder contraction occurred during gastric emptying of solids. Gallbladder refilling began when approximately 13% of solids remained in the stomach. Serum human pancreatic polypeptide showed the expected biphasic response to the meal and returned to basal levels at approximately the time of initiation of gallbladder refilling. The gastrointestinal transit time of women was twice that of men (73.6 +/- 20.2 vs. 37.5 +/- 22.7, p = 0.025). No other sex-related differences were detected. We conclude that gastric emptying of the solid portion of a meal containing fat maintains tonic gallbladder contraction through continued release of humoral mediators from small bowel and pancreas. When gastric emptying nears completion, humoral stimulation ceases and the gallbladder refills. Human pancreatic polypeptide does not appear to be responsible for gallbladder refilling.

Adult↗
PubMed1982

Gallbladder function in the human female: effect of the ovulatory cycle, pregnancy, and contraceptive steroids.

We have previously shown that in pregnancy fasting gallbladder volume is increased and emptying after a small volume liquid meal is incomplete. In this study we measured gallbladder volume throughout day and night in healthy women ingesting regular meals. Pregnant women, postpartum women, contraceptive-steroid users, and controls in both phases of the ovulatory cycle were studied. After an overnight fast gallbladder volume was measured by realtime ultrasonography in the fasting state and every 5-10 min for 90 min after breakfast. Residual volume was the lowest volume achieved and the rate constant of gallbladder emptying was calculated from the ln/linear regression of gallbladder volume vs. time. Gallbladder volume was also measured hourly from 11 AM to midnight while subjects ate regular, standard meals, allowing the determination of an average hourly volume. There was no effect of phase of the ovulatory cycle on any measure of gallbladder function. Fasting, residual, and average hourly volume were increased in all trimesters of pregnancy, but tended to return to normal in the postpartum period. Women taking contraceptive steroids had an increased fasting volume. Two distinct rates of emptying after breakfast, an early and a late one, were identified. The early rate was the same in all groups. Pregnant women had a slower late rate of emptying, but women taking contraceptive steroids had emptying rates similar to controls. Retention of bile in the gallbladder may be one reason for the increased risk of cholesterol cholelithiasis in pregnant women and in those taking contraceptive steroids.

Adult↗
PubMed1980

Restoring patency of occluded central venous catheters.

Thrombotic occlusion remains a major cause of central venous catheter removal prior to completion of therapy. Injection of a dilute solution of a potent fibrinolytic agent, urokinase or streptokinase, into the occluded Silastic central venous catheter consistently reestablishes its patency. This procedure was performed on 352 occluded silicone elastomer central venous catheters with only one failure and one minor complication. We recommend this technique for restoring patency of occluded silicone elastomer central venous catheters.

Catheters, Indwelling↗
PubMed1979

Long-term intravenous therapy with peripherally inserted silicone elastomer central venous catheters in patients with malignant diseases.

Peripherally inserted central venous silicone elastomer catheters were studied in 81 patients who had malignancy requiring prolonged intravenous therapy. The catheters remained in place from 5 to 171 days, with a median of 30 days. Ninety-one percent of the catheters were unassociated with clinical complications. Six percent of 87 inserted catheters were removed due to peripheral thrombophlebitis. Two patients developed subclavian thrombosis, requiring catheter removal. One patient had catheter-related sepsis with Staphylococcus aureus. Bacteria grew from eleven percent of the cultured catheter tips. Indwelling catheters presence did not appear to influence response to antibiotic therapy. We conclude from this pilot study that long-term central venous access with peripherally inserted silicone elastomer catheters has an acceptably low complication rate in a high-risk patient population.

Adolescent↗
PubMed1979

Continuous intravenous arabinosyl cytosine infusions delivered by a new portable infusion system.

Eighty-six patients with acute leukemia were given 116 continuous intravenous arabinosyl cytosine (Ara-C) infusions (for 24 to 432 hours) with a new portable infusion device. The infusor is powered by interchangeable elastomeric 25 ml balloon reservoirs loaded from standard syringes. The reservoir contents are discharged at nearly constant pressure through an adjustable resistance element, thereby providing flow rates from 0.4 to 2.0 ml/hour. Serum levels of labeled Ara-C delivered by the infusor were found to achieve steady-state therapeutic levels within 24 hours. The average-flow-rate-to-indicator-setting ratio determined for each infusion via scalp vein needles was 0.9 +/- 0.2. Delivery through catheters was more reliable and an average-flow-rate-to-indicator-setting ratio of 0.1 +/- 0.1 was observed. The therapeutic effectiveness of Ara-C in combination with other agents was not compromised by this delivery system. Eleven of 14 patients who received all their induction Ara-C through the infusor achieved complete remission.

Acute Disease↗