Biomedical subjects
P Lawrence
Publications and source records attributed to P Lawrence.
Phase I trial of a 96 h paclitaxel infusion with filgrastim support in refractory solid tumor patients.
A phase I study of a 96 h paclitaxel infusion with filgrastim support was performed to determine the toxicity, maximum-tolerated dose (MTD) and pharmacokinetics in patients with refractory solid tumors. In this phase I trial, the initial paclitaxel dose was 140 mg/m2/96 h followed by filgrastim (5 microg/kg/day s.c.) beginning 24 h after the paclitaxel and continued until granulocyte recovery. Cycles were repeated every 21 days. Patients with refractory solid tumors were eligible; however, only one previous chemotherapy regimen was allowed. The dose of paclitaxel was escalated by 20 mg/m2/96 h in subsequent cohorts until dose-limiting toxicity (DLT) occurred. Pharmacokinetic analysis was performed by quantitating paclitaxel concentrations at baseline, 24, 48, 72 and 96 h after the start of the paclitaxel infusion. Twenty-one patients were entered into this trial of which 19 were evaluable. A total of 52 treatment cycles were administered. DLT was seen in two of four patients at 200 mg/m2/96 h, and consisted of diarrhea, mucositis and granulocytopenic infection. The MTD of the 96 h paclitaxel infusion was 180 mg/m2 with filgrastim support. Mucosal and granulocyte toxicity were correlated with steady-state paclitaxel concentrations (Css) greater than 0.100 micromol/l. In the presence of liver function test 1.5 times or lower than normal, metastatic liver disease did not alter paclitaxel Css. Objective responses were observed in non-small cell lung cancer, small cell lung cancer and melanoma. The recommended phase II dose of paclitaxel infused over 96 h with filgrastim support is 180 mg/m2. Paclitaxel Css correlate with mucosal and granulocyte toxicity. In the presence of normal enzymatic function, metastatic liver disease does not affect paclitaxel clearance.
Effectiveness and efficiency of methods of dialysis therapy for end-stage renal disease: systematic reviews.
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Bilateral iliac artery aneurysms and pancake kidney: a case report.
Renal fusion and ectopia are anomalies of the proximal urinary tract that present a special challenge to vascular surgeons. We present a rare case of bilateral iliac artery aneurysms in a 70-year-old man with a fused pancake kidney. The patient underwent preoperative evaluation with a computed tomographic scan and angiographic examination, followed by bilateral iliac artery reconstruction. Pancake kidney is a rare renal anomaly, and its association with aortoiliac disease has been referred to only one other time in the literature. Successful management is dependent on preoperative recognition of the renal anomaly, aortographic examination to delineate renal blood supply, and careful operative preservation of renal vasculature.
Comparative morphology of the alimentary tract and its glandular derivatives of captive bustards.
This study describes the gross anatomy of the alimentary tract of Houbara Bustards (Chlamydotis undulata macqueenii), Kori Bustards (Ardeotis kori), Rufous-crested Bustards (Eupodotis ruficrista) and White-bellied Bustards (Eupodotis senegalensis) maintained in captivity by the National Avian Research Center in the United Arab Emirates. The morphology of the alimentary tract and the proportions of each region were similar in all 4 species. The length of the oesophagus, combined proventriculus and ventriculus, small intestine, and large intestine formed 24.2-28.4%, 7.3-9.7%, 40.5-55.1% and 9.1-14.7% of the total alimentary tract length respectively. Neither crop nor oesophageal enlargement was observed in the birds examined in this study, although male Kori Bustards possessed a saccus oralis in the oropharyngeal cavity. Oesophagi, proventriculi, ventriculi, caeca and large intestine were well developed in all species. The small intestine was shorter than that of other avian herbivores and granivores when compared on a bodyweight basis. The well differentiated stomachs and well developed caeca of the bustards examined in this study are characteristic of omnivores. Analysis of the mean lengths of the alimentary tract components and weight of the liver and pancreas showed sexual dimorphism in cases where male and female data were available for direct comparison.
The effects of recombinant human growth hormone and intradialytic parenteral nutrition in malnourished hemodialysis patients.
Malnutrition in hemodialysis patients is associated with increased morbidity and mortality. The use of intradialytic parenteral nutrition (IDPN) to improve nutritional parameters has been shown to be of limited benefit in most studies. We studied the use of recombinant human growth hormone (rHuGH) in potentiating the effects of IDPN in seven hemodialysis patients dialyzed with a Kt/V of 1.03 +/- 0.11 (mean +/- SEM), but with evidence of malnutrition: albumin, 3.2 +/- 0.18 g/dL; transferrin, 215 +/- 30 mg/dL; insulin-like growth factor-1 (IGF-1), 115 +/- 19 ng/mL, protein catabolic rate (PCR), 0.70 +/- 0.05 g/kg/d; and weight, 12.3% +/- 4.0% below ideal body weight. During 6 weeks of IDPN, resulting in an additional 18 +/- 4 kcal and 0.69 +/- 0.03 g of protein/kg body weight per dialysis session, albumin concentration increased to 3.5 +/- 0.14 g/dL (compared with baseline, P = NS), transferrin increased to 279 +/- 36 mg/dL (P < 0.002), IGF-1 increased to 152 +/- 32 ng/mL (P = NS), and PCR increased to 0.81 +/- 0.04 g/kg/d (P = NS). During the next 6 weeks, IDPN administration was continued and rHuGH, at a dose of 5 mg subcutaneously during each dialysis, was added to the regimen. This resulted in an increase in albumin concentration to 3.8 +/- 0.08 g/dL (P < or = 0.04 compared with end of IDPN phase), an increase in transferrin to 298 +/- 41 mg/dL (P = NS compared with end of IDPN phase), and an increase in IGF-1 to 212 +/- 45 ng/mL (P = 0.05 compared with end of IDPN phase).(ABSTRACT TRUNCATED AT 250 WORDS)
A human factors evaluation of two different machine control systems for log loaders.
The implement movement in today's mobile, heavy machinery does not correspond in a one-to-one proportion with hand control movement. This lack of correspondence places high perceptual and psychomotor demands on the operator. The objective of this study was to evaluate the human factors of two different machine control systems on a log loader in a controlled field setting. The traditional joint control system was compared with a co-ordinated control system. The two machines were tested on ten novice and six experienced operators. Operator performance was based on the time required to complete a task sequence, as well as reaction time. The results show that the novice operators performed significantly better in co-ordinated mode than they did in joint mode, whereas the experienced operators performed better in joint mode than they did in co-ordinated mode. Results indicate, however, that it would not take long for experienced operators to transfer their skills from joint control to co-ordinated control.
Bullous secondary syphilis.
An earlier standard syphilology textbook states that 'If vesicles are an essential part of an eruption in an adult, the lesions are not due to secondary syphilis'. However, vesicular and bullous eruptions do occur in congenital syphilis and rare reports of both vesicular and pustular eruptions in adults with secondary syphilis have been published. We describe a patient with a bullous-pemphigoid-like eruption and a positive VDRL in whom treatment with a course of procaine penicillin resulted in rapid permanent resolution of the eruption.
Leg ulcers in hereditary spherocytosis.
Refractory leg ulcers in two patients healed following splenectomy. Neither patient had the ethnic background or family history of haematological abnormalities to suggest a haemoglobinopathy.
Caring for the suicidal patient.
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Molecular genetics. Fruitful fruitflies in Crete.
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Solutes vs. symptoms in uremia.
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Encephalopathic toxicity: an experimental model of uremia and solute-specific dialysis.
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Enhancement and dynamic time warping of somatosensory evoked potential components applied to patients with multiple sclerosis.
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Morphological measurement of the SEP using a dynamic time warping algorithm.
A dynamic time warping technique was created to align the components of digitally high-pass (300 Hz-2500 Hz) filtered somatosensory evoked potentials evoked by median nerve stimulation recorded with a bipolar cephalic montage. A cost function was assigned related to the amount of warping necessary to match a standard wave derived from 24 normal subjects. Its value ranged from 0.525 to 2.456 (mean 1.305 +/- 0.501). This contrasted with a mean of 5.089 +/- 4.277 (range 0.701-13.972) derived from 25 patients with definite (n = 24) or possible (n = 1) multiple sclerosis chosen on the basis of having few or no clinical abnormalities at the time of testing. Fourteen (56%) of the patients had cost functions that were 3 or more S.D.s above the normal mean as compared to 3 (12%) having prolonged latency of the N19 peak. When used in combination, the cost function and latency yielded 60% abnormalities; 5 times higher than latency measurement alone.
Assessment of skin ulcer healing capability by technetium-99m phosphate angiogram and blood-pool images.
The accuracy of radionuclide angiography and blood-pool imaging using [99mTc]-phosphate to assess skin ulcer perfusion as an indicator of healing capacity was determined in 50 studies performed on 45 patients with nonhealing ulcers of the lower extremities. Two nuclear medicine physicians without clinical bias, graded the perfusion of the ulcer on the images as normal, increased or reduced with respect to the opposite limb. Patients were followed closely with aggressive local wound care for at least 14 days. Of the 31 ulcers which healed, the radionuclide study correctly predicted 30; of the 19 ulcers which did not heal, 14 were correctly predicted. Eight patients had osteomyelitis; four of those healed and four did not. The radionuclide study predicted healing in seven. Excluding those patients with osteomyelitis, the sensitivity for the radionuclide angiogram and blood-pool image in predicting healing was 96%, specificity was 87%, and accuracy was 93%. This technique is a simple, reliable way to predict the microcirculatory adequacy for ulcer healing. Specificity is diminished in the presence of osteomyelitis.
Value of a 24-hour image (four-phase bone scan) in assessing osteomyelitis in patients with peripheral vascular disease.
The delayed images of the four-phase 99mTc phosphonate bone scan are compared with the delayed images of the three-phase study in patients with diabetes mellitus and/or peripheral vascular disease and suspected osteomyelitis. Three-phase bone imaging includes an immediate postinjection radionuclide angiogram, a blood-pool image, and delayed static images to 7 hr. The four-phase study adds a 24-hr static image. The scan is positive for osteomyelitis if images show progressively increasing lesion to background activity ratios over time. The results of analyzing 21 three- and four-phase bone scans in 17 patients were correlated with clinical course, cultures, and/or x-rays, gallium scans, and CT scans. The accuracy of four-phase bone imaging for diagnosing osteomyelitis was 85%; for three phase, 80%. Sensitivity for four phase was 80%; specificity was 87%. Sensitivity for three phase was 100%; specificity was 73%. Since overall accuracy of the four-phase study is slightly better than three phase, in these patients with diabetes mellitus and/or peripheral vascular disease, the addition of a 24-hr image, creating a four-phase bone scan, is recommended.
Mouth-valve-mask ventilation.
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