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Biomedical subjects

W P Pierson

Publications and source records attributed to W P Pierson.

At least 19 recordsLinked to original sources
PubMed1989

Alterations in oxygen saturation and ventilation after intravenous sedation for peritoneoscopy.

The effect of intravenous sedation on oxygen saturation and ventilation was studied in 11 patients undergoing peritoneoscopy. Oxygen saturation (mean +/- SD) decreased from baseline (94.7% +/- 1.7%) to nadir (78.6% +/- 10.7%) after sedation. Respiratory depression was evident in these patients by concomitant decreases in minute ventilation and tidal volume. Baseline to nadir arterial blood gas changes in eight patients were consistent with hypoventilation and also suggested a superimposed ventilation perfusion mismatch. Mean respiratory rate did not significantly change during peritoneoscopy. Peritoneal gas insufflation stimulated increased ventilation and oxygen saturation, but no further changes in PCO2 or pH. We conclude that serious arterial oxygen desaturation and possibly some ventilation perfusion mismatch occur after sedation with intravenously administered meperidine-diazepam for peritoneoscopy with resultant hypoxemia, hypercarbia, and acidosis.

Adolescent↗
PubMed1988

Capreomycin kinetics in renal impairment and clearance by hemodialysis.

The single-dose kinetics of capreomycin are described for 12 renal patients and seven healthy control subjects. Creatinine clearances (CrCl) ranged from zero to 121 ml/min. After single-dose intravenous infusions, mean +/- SD capreomycin clearance values (L/kg/h x 10(-2)) were 0.558 +/- 0.160 for the dialysis group (n = 4, CrCl = 1.4 +/- 1.9), 1.77 +/- 0.45 for the moderate renal group (n = 3, CrCl = 25 +/- 5), 2.82 +/- 1.52 for the mild renal group (n = 4, CrCl = 46 +/- 5), and 5.73 +/- 1.54 for the normal renal group (n = 7, CrCl = 109 +/- 11); p less than 0.01, using analysis of variance. The correlation between capreomycin clearance and CrCl was r = 0.90. Hemodialysis cleared clinically significant amounts of capreomycin. These data imply that capreomycin maintenance doses need to be reduced for renal patients.

Adolescent↗
PubMed1987

Normal standards for kidney length in premature infants: determination with US. Work in progress.

In 52 healthy premature infants, 104 kidneys were sonographically examined and kidney length was measured. Kidney length was compared with four parameters: body weight, body length, body surface area, and gestational age. Scatter plots of these data demonstrated that kidney length versus body weight conformed well to a linear distribution with a high correlation coefficient. A nomogram for kidney length versus body weight in premature infants is also presented.

Body Height↗
PubMed1987

Prolongation of survival for high-grade malignant gliomas with adjuvant high-dose BCNU and autologous bone marrow transplantation.

Employment of postoperative brain irradiation in the initial management of high-grade malignant glial tumors has now become standard. The addition of conventional chemotherapy to irradiation has not significantly improved median survival beyond 1 year. We treated 25 consecutive patients (13 pilot patients and 12 protocol patients) with histologically confirmed unresectable grade 3 or 4 malignant gliomas with high-dose BCNU (carmustine) followed by autologous bone marrow transplantation and whole brain irradiation. Within 3 weeks of initial surgery, each patient had autologous bone marrow stored (median 2 X 10(8) nucleated cells/kg), and then received BCNU 1,050 mg/m2 intravenously (IV). Peripheral granulocytes recovered (greater than 500/microL) at a median of 19 days (range, 10 to 37 days), and platelets recovered (greater than 20,000/microL) at a median of 18 days (range, 13 to 40 days), following bone marrow infusion. Patients received 60 Gy whole brain irradiation when granulocytes were greater than 1,500/microL. Toxicity was well tolerated. Nausea occurred in 19 patients (76%); however, only eight patients (32%) experienced vomiting (mild in three, moderate in five). Eleven patients (44%) did not require empiric antibiotics, six of whom never developed an absolute granulocyte count less than 500/microL. Three patients with a poor performance status died early (one seizure with vomiting and asphyxiation; one, klebsiella urinary tract infection (UTI) with bacteremia; one, candidal pneumonia), and one additional patient who was performing well died of pulmonary hemorrhage. The 13 pilot patients have now been followed for a median of 23 months, with a significant survival advantage compared with the 52 consecutive historical control patients who received similar surgery and radiotherapy without high-dose BCNU (P = .037). The overall study group of 25 patients also has a significant survival advantage when compared with the same historical control group, with a projected median survival of 26 months (P = .007). This new approach using early postoperative intensive therapy consisting of high-dose BCNU, autologous bone marrow transplantation, and whole brain irradiation appears to significantly improve survival.

Adult↗
PubMed1987

Metoclopramide effect on esophageal peristalsis in normal human volunteers.

There is relatively poor documentation of the effect of metoclopramide on the human esophageal body. We, therefore, studied several parameters of esophageal function in 19 normal volunteers both before and after 20 mg intravenous metoclopramide. Contraction amplitude, wave duration, velocity, and propagation time were increased after metoclopramide. These changes were more pronounced in the distal esophagus. At the most distal manometric recording level located 2 cm above the lower esophageal sphincter, contraction amplitude increased 39% (p less than 0.01) and duration increased 22.5% (p less than 0.01) after metoclopramide. We conclude that in normal subjects metoclopramide has an effect predominant in the distal body of the esophagus.

Adult↗
PubMed1986

Quinidine assays: enzyme immunoassay versus high performance liquid chromatography.

Plasma quinidine results determined by enzyme multiplied immunoassay (EMIT) (Syva) were compared with results from a quinidine-specific high performance liquid chromatographic (HPLC) assay. During a clinical study, 16 patients with stable ventricular arrhythmias were treated with three oral quinidine preparations given during three consecutive 3-day periods. Seventeen plasma samples were drawn from each patient at steady-state during each period. Each specimen was divided into two portions, one for assay by EMIT and the other for assay by HPLC. EMIT assays were done on a Syva Autolab 6000 System using Syva quinidine kits and bilevel Ortho Diagnostics controls. The overall mean (+/- SD) quinidine concentrations by EMIT and HPLC were 2.16 +/- 0.58 and 1.81 +/- 0.60, respectively, n = 816, with a mean overall EMIT/HPLC ratio of 1.23 +/- 0.18. Mean ratios in individual patients ranged from 1.01 to 1.56; the average of mean individual ratios was 1.23 +/- 0.13. The EMIT assay, which also reports dihydroquinidine and small amounts of quinidine metabolites as quinidine, reported quinidine values that averaged 1.2-fold greater than results from a quinidine-specific HPLC method.

Chromatography, High Pressure Liquid↗
PubMed1986

Colon cleansing: acceptance by older patients.

The influence of age on patient acceptance and adequacy of preparation was evaluated in 557 patients from our previous colon cleansing studies for colonoscopy, barium enema, and elective colon surgery. Since study design was similar for all studies, the patients were combined and stratified to those over age 60 (old) and those 60 or younger (young). Patients were previously randomized in their respective studies to polyethylene glycol electrolyte gut lavage solution (old, 105; young, 181) or standard prep (old, 71; young, 20). Patient response data were analyzed in two fashions; distribution of response scores and minimal responses. When the distribution of scores were compared, older gut lavage patients had fewer cramps but more overall discomfort than younger patients receiving the lavage preparation. Older standard prep patients had less overall discomfort than younger standard prep subjects. Comparison of responses rated as minimal showed the older lavage patients to have fewer cramps than younger lavage patients and fewer cramps than standard preparation patients of similar age. None of the other assessed symptoms was significantly different between age groups or prep method. Most patients had minimal symptoms regardless of age or prep. Age did not influence adequacy of preparation for gut lavage or standard prep methods.

Age Factors↗
PubMed1985

Bond strengths of three resin systems used with brackets and embedded wire attachments.

Orthodontic wire bonded directly to teeth with a resin adhesive system has been used to establish anchor units for procedures in orthodontics as well as for splinting teeth in other disciplines. This procedure can save the cost and time of placing a bracket. In addition, several different resin systems have been used for this procedure as well as for placing brackets. The purpose of this study was to determine the strength of three adhesive systems used to bond orthodontic wires directly to teeth and to compare these values with those found for directly bonded orthodontic brackets. Equal sample sizes of brackets or wires were attached to 240 human teeth with either Concise, Miradept, or Endur in a standardized area of etched enamel. Shear and tensile strengths were measured at 30 minutes and at 48 hours. At 30 minutes brackets were significantly stronger than embedded wires, and Concise was significantly stronger than either of the other resins. However, all significant differences between any of the three resin systems using either bonded brackets or wires disappeared at 48 hours. Whether or not this initial strength difference is clinically significant remains speculative.

Acrylic Resins↗
PubMed1985

Metoclopramide kinetics in patients with impaired renal function and clearance by hemodialysis.

Metoclopramide kinetics were examined in 24 adult patients with diminished renal function and in eight healthy subjects with normal renal function. Creatinine clearance correlated with metoclopramide plasma clearance, renal clearance, nonrenal clearance, and elimination t1/2. Regardless of renal function, renal clearance accounted for less than or equal to 21% of total plasma clearance. Nonrenal clearance was reduced in patients and accounted for most of the reduction in plasma clearance. The comparatively small plasma clearances in patients imply that maintenance doses should be reduced accordingly to avoid drug cumulation. Metoclopramide clearance by hemodialysis was also assessed in four patients. Metoclopramide losses from hemodialysis were relatively small compared to estimates of total body metoclopramide stores. Compensatory dosage increases are probably unnecessary for most patients. These data also suggest that hemodialysis is not likely to be effective in metoclopramide overdose.

Adolescent↗
PubMed1985

Golytely lavage--is metoclopramide necessary?

During Golytely cleansing for colonoscopy, two dose forms of oral metoclopramide were evaluated in separate studies for patient tolerance and adequacy of preparation. In study 1, patients were randomized to 10 mg metoclopramide (n = 21) or placebo (n = 27); in study 2, 20 mg metoclopramide (n = 21) was compared to placebo (n = 25). Ten milligrams metoclopramide was not significantly different from placebo in patient acceptance for any of the assessed symptoms. Patients taking 20 mg metoclopramide had less cramping (p = 0.02), but more nausea (p = 0.03) than placebo. Time for rectal effluent to clear was similar in all groups. The percentage of patients preferring Golytely was similar in both studies (70-79%, p = NS) and 85% of all patients were willing to repeat Golytely. Physician assessment of colon cleansing showed no difference between metoclopramide or placebo in either study, with adequate preparations in 97% and optimal cleansing in 80% of all patients. Neither 10 nor 20 mg oral metoclopramide improved adequacy of colon cleansing for colonoscopy or decreased symptoms associated with Golytely lavage.

Adolescent↗
PubMed1985

Statistical determinants of success and complications of thrombolytic therapy for arterial occlusion of lower extremity.

In this prospective study, we have documented the limited usefulness of thrombolytic therapy in the management of all patients with arterial occlusion of the lower extremities. We have also emphasized the significant rate of recurrent thrombosis unless an underlying obstructive lesion is corrected surgically after clot dissolution. Because thrombolytic drugs can lyse clots of a duration of several weeks, we recommend consideration of fibrinolytic therapy for subacute graft occlusions and segmental arterial thromboses. In such instances, thrombolysis is likely to reveal a focal underlying lesion that is correctable by a limited anastomotic revision or balloon angioplasty. Without fibrinolytic therapy, these older occlusions generally require more extensive bypass grafting or graft replacement. In contrast, we are less enthusiastic about thrombolytic therapy for distal small vessel thrombosis or embolism because complete clot lysis was achieved in only one of five patients. The primary problems with regional arterial low dosage thrombolytic infusions are bleeding at the angiographic catheter entry site and distal thromboemboli of the lysing clot. These difficulties may discourage wide acceptance of fibrinolytic therapy. However, they can be minimized by careful technique. Although its usefulness is limited and complications are common, catheter directed arterial low dosage thrombolytic therapy can be an important initial step in the diagnosis and treatment of selected arterial occlusion of the lower extremities.

Aorta, Abdominal↗
PubMed1984

The validity of transcranial radiography in diagnosing TMJ anterior disk displacement.

Two transcranial radiographic methods for determining anterior disk displacement in the TMJ were evaluated in comparison with results obtained from arthrography. Both transcranial radiographic methods could only accurately predict the presence of an anteriorly displaced disk in a range of 26% to 56% of the time (for example, the methods gave false-negative results 44% to 74% of the time). The methods were more valuable in correctly identifying joints that were free of disease, achieving this identification anywhere from 64% to 96% of the time. Although noninvasive, these two transcranial radiographic techniques produced results that lacked validity and, therefore, remain of questionable value to the clinician who is diagnosing anterior disk displacement.

Cartilage, Articular↗
PubMed1984

Comparison of Golytely lavage with standard diet/cathartic preparation for double-contrast barium enema.

In a two-part study, two groups of 100 outpatients each were randomly assigned a colon preparation. In part 1, a standard 1-day diet/cathartic combination was compared with Golytely. In part 2, diet/cathartics was compared with Golytely plus Dulcolax (bisacodyl). The standard preparation provided good or excellent feces removal in 81 (80%) of 101 subjects. Golytely alone was successful in only 21 (53%) of 40 patients, but Golytely followed by Dulcolax achieved good or excellent feces removal in 31 (82%) of 38. Degraded mucosal coating with Golytely alone, due to excessive fluid retention, was also corrected by the addition of Dulcolax. Golytely alone is not an adequate method of colon cleansing for double-contrast barium enema, but Golytely plus Dulcolax is as effective as the standard preparation.

Adult↗
PubMed1984

Passive smoking and thiocyanate concentrations in pregnant women and newborns.

Serum thiocyanate concentrations have been used as a marker of cigarette exposure in both smokers and nonsmokers. The authors used this measure to estimate passive exposure in low-risk healthy pregnant women at term. Three groups were compared: smokers, passive smokers, and nonsmokers. The mean thiocyanate concentration (95 mumol/L) was significantly higher (P less than .001) in smokers than in passive smokers (35.9 mumol/L) or nonsmokers (32.3 mumol/L). The maternal and umbilical mean cord thiocyanate concentrations were similar in the smoking group (95 versus 72 mumol/L). Although the umbilical cord levels in the infants of passive smokers and nonsmokers were similar (26 versus 23 mumol/L), both levels were significantly lower than those of smokers. Most important, there was an inverse relationship between umbilical cord thiocyanate concentration and birth weight (P less than .001). The authors found no evidence that passive cigarette smoke exposure resulted in higher maternal or umbilical cord thiocyanate concentrations than found in nonsmokers.

Adult↗
PubMed1984

Comparison of colon cleansing methods in preparation for colonoscopy.

Colonoscopy cleansing regimens were evaluated in 197 patients randomized in two study phases to one of four methods: group 1 (64 patients), 3-day clear liquid diet; group 2 (40 patients), 3-day minimum-residue diet; group 3 (44 patients), 1-day minimum-residue diet; group 4 (49 patients), Golytely. Groups 1-3 also received laxatives and enemas before colonoscopy. Physician assessment by endoscopists unaware of the method of colon cleansing favored group 4 (p less than 0.001), with good to excellent preparations achieved in 69% of group 1, 80% of groups 2 and 3, and 92% of group 4. Group 4 patients also experienced less abdominal distress (p less than 0.01). Breath hydrogen and methane levels were measured in groups 3 and 4 both before and after preparation. The decrease in pre- to postprep levels of hydrogen and methane were not significantly different between the groups and postprep gas concentrations were below combustible levels in both groups. There were no clinically significant differences between the four groups for any of the other measured hematologic or biochemical parameters. It is concluded that Golytely is a safe, effective method of colon cleansing, well tolerated by patients.

Adult↗