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Biomedical subjects

J G Wagner

Publications and source records attributed to J G Wagner.

At least 19 recordsLinked to original sources

Absorption of flurbiprofen in the fed and fasted states.

The oral absorption of flurbiprofen, an antiinflammatory nonsteroidal compound, was compared in the fasted vs the fed state. When ingested as an aqueous solution of the sodium salt, absorption kinetics followed a monoexponential pattern in half of the subjects and a bimodal pattern with a lag time before the onset of the second phase of absorption in the other half of the subjects. When ingested in the free acid form as a tablet either with water (fasted state) or with water 15 min after 330 ml of apple juice (fed state), flurbiprofen absorption was always bimodal, and the lag time before the onset of the second phase was shown to be dependent on the gastric emptying time (r = 0.623, P less than 0.01). The gastric emptying times were significantly longer when the drug was administered in the fed state (average GET = 57 min in the fasted state and 102 min in the fed state; P less than 0.01). These results suggest that gastric emptying effects are one important way in which absorption of drugs can be affected by meal intake.

Administration, Oral

Effect of intraperitoneal injection volume and antibody protein dose on the pharmacokinetics of intraperitoneally administered IgG2a kappa murine monoclonal antibody in the rat.

The i.p. route of antibody administration offers a regional delivery advantage to the peritoneal cavity. In an effort to optimize this method of delivery, the volume of i.p. injection and total protein dose were examined for their effect on the absorption and disposition of an IgG2a kappa murine monoclonal antibody. 5G6.4, administered i.p. Normal rats (Sprague-Dawley) were given one of two protein doses (1-2 or 100 micrograms) of 125I-5G6.4 in a 2.0-ml i.p. injection volume. In both cases the same radiation dose (approximately 20 mu Ci/rat) was administered since only the tracer level (1-2 micrograms) was labeled. Hence, the 100-micrograms dose consisted of approximately 2 micrograms of labeled antibody with 98 micrograms of unlabeled antibody. In a separate experiment, two i.p. injection volumes (2.0 or 20.0 ml) of 125I-5G6.4 (approximately 20 mu Ci/rat) were administered to normal Sprague-Dawley rats. Pharmacokinetic modeling of the whole blood radioactivity levels was undertaken for both groups. The liver, kidney, muscle, lung, diaphragm, and anterior mediastinal lymph nodes were excised upon sacrifice and tissue levels at sacrifice were recorded. The volume of i.p. injection is shown to be a significant factor with respect to i.p. transport. Maximum concentration in the blood, Cmax, was reduced (P less than 0.1) and time of maximum concentration, tCmax was prolonged (P less than 0.05) from 8.4 h (in the 2-ml group) to 14.5 h (in the 20-ml group). Both contribute to a modest reduction in AUC(0----infinity) (P less than 0.15) in which AUC is the area under the concentration-time curve. The increase in blood clearance, Clb, at the higher injection volume (0.287 ml/h for the 20-ml volume and 0.194 ml/h for the 2-ml volume) is presumably due to increased diuresis resulting from autoregulation of fluid removal via lymphatic drainage. Volume of distribution, Vd, is increased since Vd and Clb are functionally proportionate and elimination is assumed constant. Tissue levels at sacrifice, except for the thyroid and anterior mediastinal lymph nodes, were the same. Mean thyroid levels were reduced in the 20-ml group (P less than 0.05) by 22.5%, likely as a result of increased diuresis. Increased nodal uptake (P less than 0.01) can be attributed to the dilution effect of the bolus injection. The rate of mass transfer is greater for the 2-ml group up to 4 h postinjection. Subsequently, the mass transfer rate is greater for the 20-ml group.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals

In vitro radiation resistance among cell lines established from patients with squamous cell carcinoma of the head and neck.

Twenty-five squamous cell carcinoma (SCC) cell lines from 20 patients with head and neck cancer were assessed for radiosensitivity in vitro using a 96-well plate assay. Four non-SCC lines were also tested. Radiation sensitivity of individual cell lines was compared using the area under the survival curve (AUC) as a measure of the mean inactivation dose. Tumor lines were tested with either a cobalt-60 (60Co) gamma-irradiator having a dose rate of 100 cGy/minute or with a 4-meV photon beam having a dose rate of 200 cGy/minute. The mean AUC of the 25 SCC cell lines was 188 +/- 7 (SEM) cGy (range, 100 to 250 cGy) whereas the four non-SCC lines had a mean AUC of 225 +/- 9 cGy. The SCC cell lines with mean inactivation dose values greater than 188 cGy were classified as relatively radioresistant whereas those with values less than 188 cGy were considered relatively radiosensitive. In seven cases SCC cell lines were derived from patients who had already received radiation therapy. In four of these cases the tumor cell lines were radioresistant (AUC, 210 to 250) but in the other three cases the tumor lines were radiosensitive (AUC, 160 to 180). Thus, failure of a tumor to respond to radiation did not always select for radioresistant cells. The mean of the AUC for cell lines from previously irradiated patients (197 +/- 11 cGy) did not differ significantly from that of the cell lines from patients who received no prior radiation therapy (182 +/- 9 cGy). However, among radiation-resistant lines those from the four previously irradiated patients were significantly more resistant (mean AUC = 235 +/- 9) than seven other radioresistant lines from nonirradiated patients (mean AUC, 208 +/- 4) (P = 0.0194). In four cases more than one cell line was derived from different tumor specimens in the same patient. In each of these cases the lines from the same patients were similar to one another in their degree of radioresistance. Based on these observations the authors conclude that the degree of in vitro radiation resistance is an inherent property of some squamous cell tumors.

Adult

Early indications of monocrotaline pyrrole-induced lung injury in rats.

Monocrotaline pyrrole (MCTP), a putative metabolite of the naturally occurring plant toxin, monocrotaline (MCT), causes lung injury, pulmonary hypertension, and right cardioventricular hypertrophy when administered intravenously to rats. The lesions caused by MCTP administration are similar to those caused by MCT but appear to occur on a slightly accelerated time course. To explore the onset and development of lung lesions, male Sprague-Dawley rats were treated with a single, intravenous injection of MCTP, and several markers of lung injury were evaluated at early times after administration. Rats received 3.5 mg MCTP/kg or an equal volume of the vehicle, N,N-dimethylformamide (DMF), via the tail vein at time 0 and were killed at 4, 12, 24, 48, 72, or 120 hr after treatment. Beginning at 4 hr, MCTP-treated rats had increased wet lung-to-body-weight ratios (LW/BW). The LW/BW remained elevated at 12 hr, returned to baseline at 24 hr, then increased steadily over the next few days. At 24 hr, the protein concentration of cell-free bronchoalveolar lavage fluid (BALF) was slightly elevated. Lactate dehydrogenase activity in cell-free BALF samples was moderately increased 48 hr after MCTP. Changes in these markers were modest initially but became much more pronounced by 120 hr. Total nucleated cell counts in BALF were variable but were moderately elevated at 120 hr. Cytologic examination of the BALF samples revealed small but significant infiltrates of segmented neutrophils at 4 hr and relatively large infiltrates of segmented neutrophils and small lymphocytes at 120 hr post-treatment. Mature neutrophils had degenerate cytomorphologic characteristics at both 4 and 120 hr. These results confirm that pronounced lung injury is delayed for several days after a single, intravenous administration of MCTP, but they also indicate that subtle lung injury can be detected using quantitative markers quite early after MCTP administration.

Animals

Variability of 5-bromo-2'-deoxyuridine incorporation into DNA of human glioma cell lines and modulation with fluoropyrimidines.

Human glioma-derived cell lines were found to vary in their ability to incorporate the radiosensitizer 5-bromo-2'-deoxyuridine (BrdUrd) into DNA after one cell doubling. The U-251 cell line was the best incorporator of BrdUrd, whereas U-118 and D-54 demonstrated poor incorporation with respective C50 (BrdUrd concentration required for 50% of the maximum amount of BrdUrd incorporation into DNA) values of 2.8- and 6-fold greater than that of U-251 (P less than 0.001). Modulation of radiosensitizer uptake into DNA could be achieved using the thymidylate synthase inhibitors 5-fluorouracil or 5-fluoro-2'-deoxyuridine (FdUrd). Incorporation into U-251 cells increased only slightly in the presence of the fluoropyrimidines. The BrdUrd concentration required for 50% of the maximum amount of BrdUrd incorporation into DNA changed (P less than 0.001) from 1.8 +/- 0.11 microM (SD) in the absence of a modulator to 1.1 +/- 0.09 or 1.1 +/- 0.16 microM in the presence of 10 microM 5-fluorouracil or 5 nM FdUrd, respectively. The D-54 cell line, which was the worst incorporator of BrdUrd, was found to have an extensive amount of BrdUrd into DNA following biomodulation. The C50 in the absence of modulation was 7.3 +/- 1.3 microM, which was reduced (P less than 0.001) to 0.62 +/- 0.04 and 0.32 +/- 0.13 microM, respectively, in the presence of 10 microM 5-fluorouracil and 5 nM FdUrd. This represents a 12- to 22-fold reduction in the concentration of radiosensitizer required to achieve the same level of BrdUrd incorporation into DNA. Furthermore, this enhancement of BrdUrd DNA incorporation seen in the presence of the fluoropyrimidines is observed at clinically achievable concentrations. The degree of radiosensitization was solely dependent upon the amount of BrdUrd incorporated into DNA. D-54 cells grown in the presence of 0.18 microM BrdUrd plus 5 nM FdUrd or 2.8 microM BrdUrd alone yielded a similar level of BrdUrd incorporation into DNA and radiosensitization, though a 15-fold lower BrdUrd concentration was used in the presence of FdUrd. The combined use of a radiosensitizer with a fluoropyrimidine may overcome poor incorporation of BrdUrd into DNA that may exist among resistant subpopulations of cells within malignant glioma.

Bromodeoxyuridine

Exact dosing times calculations in linear pharmacokinetics.

The problem of determining the particular dosing time, tau, that results in a certain ratio between peak and trough drug levels at steady state (ss) is addressed. Calculation of tau in combination with simple dose linearity principles ensures constraint on the drug level variations at ss, contrary to calculations based on only clearance principles. It is shown that the dosing time problem is solved using a nested, single-variable rootsolving. Using a derivative-free, robust, single-variable rootsolver enables automatic, reliable calculations of tau. An algorithm and computer program, SSTATE, for the automatic calculation of tau in intra- and extravascular dosings are presented. Contrary to various approximation formulae proposed in the past, SSTATE provides solutions that are exact. SSTATE provides additional ss parameters such as time to peak, and maximum, minimum, and mean levels, and can also be executed in a simulation mode to explore various practical dosage regimen schemes. Dosage regimen calculations for quinidine are presented to demonstrate the practical utility of the proposed approach. It is also demonstrated by simulation studies that some approximation formulae previously proposed may produce excessive errors, especially when applied to extravascular dosings.

Algorithms

Absorption of flurbiprofen through human buccal mucosa.

The absorption of flurbiprofen through human buccal mucosa was studied after 25 mL of a 2.5-mg/mL solution (pH 4) of the drug in a cosolvent mixture (ethanol 95%:glycerin:propylene glycol:0.3 M sodium acetate buffer, 10:40:30:20) was held and circulated in the mouth for 5 min in a "buccal absorption test." The results were compared with those obtained after oral administration of 25 mL of a solution (pH 7) of sodium flurbiprofen having the same concentration. Twelve subjects participated in the crossover study. After the buccal treatment, mean Cmax and Tmax values were 0.751 micrograms/mL and 41 min, respectively. Average Cmax and Tmax values after the oral treatment were 10.8 micrograms/mL and 32 min, respectively. Mean dose-corrected AUCs were 0.0854 and 0.811 (micrograms.h/mL)/mg for the buccal and the oral treatments, respectively. The absorption kinetics after the buccal treatment were evaluated using the Exact Loo-Riegelman Method (ELRM). Buccal plasma flurbiprofen concentration-time data for 11 subjects were very well fitted by reconstructed curves using ka and the lag-time obtained from ELRM analysis of the buccal data and the disposition parameters obtained from the oral data. These results strongly support the concept of intrasubject constancy of flurbiprofen disposition parameters. Analysis, by ELRM, of the plasma concentration-time data obtained after the buccal treatment indicated first-order absorption, with a mean ka value of 3.9 +/- 2.2 h-1. This value was significantly different (0.05 greater than p greater than 0.02) from the ka after oral treatment (7.89 +/- 5.2 h-1), obtained from the triexponential fitting of the oral plasma data.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption

Stepwise determination of multicompartment disposition and absorption parameters from extravascular concentration-time data. Application to mesoridazine, flurbiprofen, flunarizine, labetalol, and diazepam.

When disposition is monoexponential, extravascular concentration-time (C, t) data yield both disposition and absorption parameters, the latter via the Wagner-Nelson method or deconvolution which are equivalent. Classically, when disposition is multiexponential, disposition parameters are obtained from intravenous administration and absorption data are obtained from extravascular C, t data via the Loo-Riegelman or Exact Loo-Riegelman methods or via deconvolution. Thus, in multiexponential disposition one assumes no intrasubject variation in disposition, a hypothesis that has not been proven for most drugs. Based on the classical two- and three-compartment open models with central compartment elimination, and using postabsorptive extravascular C, t data only, we have developed four equations to estimate k10 when disposition is biexponential and two other equations to estimate k10 when disposition is triexponential. The other disposition rate constants are readily obtained without intravenous data. We have analyzed extravascular data of flurbiprofen (12 sets), mesoridazine (20 sets), flunarizine (5 sets), labetalol (9 sets), and diazepam (4 sets). In the case of diazepam intravenous C, t data were also available for analysis. After disposition parameters had been estimated from the extravascular data the Exact Loo-Riegelman method with the Proost modification was applied to the absorptive extravascular data to obtain AT/VP as a function of time. These latter data for each subject and each drug studied were found to be fitted by a function indicating either simple first-order absorption, two consecutive first-order processes, or zero-order absorption. After absorption and disposition parameters had been estimated, for each set of extravascular data analyzed, a reconstruction trend line through the original C, t data was made. The new methods allow testing of the hypothesis of constancy of disposition with any given drug. There is also a need for new methods of analysis since the majority of drugs have no marketed intravenous formulation, hence the classical methods cannot be applied.

Algorithms

An evaluation of procoagulant activity in the peripheral blood of rats treated with monocrotaline pyrrole.

Monocrotaline pyrrole (MCTP), a putative toxic metabolite of the naturally occurring pyrrolizidine alkaloid, monocrotaline, causes pulmonary vascular thrombi that are associated with vascular remodeling, pulmonary hypertension, and right cardioventricular hypertrophy in rats. The thrombi are composed of platelets and fibrin and occur in the absence of vascular necrosis. Since thrombosis may result from excessive procoagulant activity in the systemic circulation, we evaluated the hemostatic system of rats treated with MCTP to determine if a hypercoagulable state developed in the peripheral blood. Male Sprague-Dawley rats received a single, bolus injection of MCTP (3.5 mg/kg) or an equal volume of the N,N-dimethylformamide (DMF) vehicle in the tail vein. Rats were killed at 1, 3, 5, 8, 11, or 14 days after toxin administration, and several markers of lung injury and hemostasis were evaluated. The protein concentration of cell-free bronchoalveolar lavage fluid (BALF) from MCTP-treated rats was slightly elevated at 1 and 3 days. At 5 days the elevation had become more pronounced, and values increased markedly thereafter. The wet lung-to-body-weight ratio and lactate dehydrogenase activity of cell-free BALF from rats treated with MCTP were mildly increased at 3 days. Increases in these markers progressed at 5 days and values reached a plateau thereafter. MCTP-treated rats had moderately increased total nucleated cell counts in BALF at 5 days, and counts increased markedly thereafter. Right cardioventricular hypertrophy was first detected at 8 days in MCTP-treated rats and became more pronounced with time. The prothrombin time and modified prothrombin time of MCTP-treated rats were consistently greater than those of controls. Although statistically different, these values never exceeded the range of normal values. The activated partial thromboplastin time of MCTP and control rats was variable. Only at Day 14 did MCTP-treated rats have significantly longer activated partial thromboplastin times than those of controls, and these values were within the normal range. Rats treated with MCTP had statistically significant elevations in antithrombin 3 activity at Day 8 and of fibrinogen concentration and antithrombin 3 activity at Day 11 that exceeded the normal range. Platelet numbers of both MCTP- and DMF-treated rats were greater than normal on Day 1 but quickly returned to baseline. The plasminogen values of rats treated with MCTP were lower than controls on Day 5 only. These results suggest that the pulmonary vascular thrombi induced by administration of MCTP to rats are not mediated by an excess in procoagulant activity in the peripheral blood.

Animals

The uptake and efflux of doxorubicin by a sensitive human bladder cancer cell line and its doxorubicin-resistant subline.

The uptake and efflux of doxorubicin (Dox) were investigated in a human bladder cancer cell line (UM-UC-6) and in a multi-drug resistant (mdr) subline (UM-UC-6Dox). Unlike previous reports, the initial uptake kinetics of Dox, and its accumulation and retention to steady-state were modelled mathematically. Cells were incubated with Dox and the amount of Dox in the cellular and medium phases was measured by a specific HPLC method. When monitored for 1 min from 0.02 microM to 25 microM Dox, the uptake was very rapid but was significantly faster in the resistant cell line. The initial rate of uptake at t = 0 followed Michaelis-Menten kinetics yielding Vmax values (the maximal rate of uptake) of 15.0 +/- 1.7 and 12.9 +/- 1.2 nmol/10(6)/min and Km (rate at Vmax/2) of 25.2 +/- 4.7 and 16.4 +/- 2.9 microM for UM-UC-6 and UM-UC-6Dox, respectively. There was no metabolism of Dox by keto-reduction or reductive hydrolysis. At 1.0 microM the uptake of Dox to steady-state was biexponential but there was no difference in total cellular Dox concentration between the two cell lines at equilibrium. A 3 compartment sequential closed model was fitted yielding significantly different values for the intercompartmental and hybrid rate constants, indicating altered intracellular distribution in resistant cells. Verapamil (10 microM), trifluoperazine (10 microM) or Tween 80 (0.005%) had no effect on the uptake or efflux of Dox. The UM-UC-6Dox line appeared to show atypical mdr characteristics since net drug accumulation was not lowered and classic P-glycoprotein inhibitors were not effective. The primary mechanism of Dox resistance is not enhanced metabolism or lowered intracellular concentrations.

Chromatography, High Pressure Liquid

Effect of verapamil on the uptake and efflux of etoposide (VP16) in both sensitive and resistant cancer cells.

The effect of calcium antagonist verapamil on the uptake and efflux of Etoposide (VP16), a semi-synthetic derivative of podophylotoxin and a broad spectrum antineoplastic agent, has been investigated and compared in sensitive (UM-UC-2) and resistant (UM-UC-9) human bladder cancer cells, and L1210 leukemia cells, by using both radioisotope (3[H]-VP16) liquid scintillation and high performance liquid chromatography assay with electrochemical detection. The uptake of VP16 was rapid in all three cell lines, showing an initial rapid linear phase followed by a second slower phase, but at steady state the ratios of intracellular to extracellular VP16 concentrations were only 0.004-0.006. No significant difference in drug uptake was observed in sensitive UM-UC-2 and resistant UM-UC-9 cells at all concentrations studied. Verapamil at a concentration of 10 microM enhanced the intracellular VP-16 levels in all sensitive and resistant cell lines. The increments were 21.5% for UM-UC-2, 11.8% for UM-UC-9, and 31.0% for L1210 cells after 30 minutes incubation with 1 microM VP16. A slower efflux of VP16 was observed in verapamil treated cells in all three cell lines. There was a small increase in the nonexchangeable components in verapamil treated cells, although only 5-10% of VP16 was retained. No peak other than that of VP16 was detected in the HPLC chromatogram of extracts from both cell pellet and influx or efflux medium.

Animals

Comparison of response of bovine and porcine pulmonary arterial endothelial cells to monocrotaline pyrrole.

Monocrotaline (MCT)-induced vascular injury in liver and lung may be caused by interaction of MCT metabolites such as monocrotaline pyrrole (MCTP) with vascular cells. Responses of bovine and porcine pulmonary artery endothelial cells (BECs and PECs, respectively) to a single administration of MCTP were compared. MCTP caused a delayed and progressive release of lactate dehydrogenase (LDH) activity from BECs and a gradual decrease in monolayer cellularity. Surviving cells became markedly hypertrophic. PECs were less sensitive to the cytolytic effects of MCTP, showing minimal cell detachment and little release of LDH activity. However, monolayer cellularity, as assessed by PEC enumeration, decreased in a dose-dependent manner. Hypertrophy of surviving PECs was less pronounced than in BECs. MCTP caused enhanced release of prostacyclin from monolayers of BECs and PECs exposed to 10 micrograms MCTP/ml, and concentrations of 0.5 microgram/ml or greater caused equivalent reduction in colony-forming efficiency in both cell types. In summary, whereas BECs were more susceptible to the cytolytic and hypertrophic effects of MCTP, BECs and PECs responded similarly with regard to prostacyclin release and were equally sensitive to the cytostatic effects of this compound.

6-Ketoprostaglandin F1 alpha

Investigations into the route of uptake and pharmacokinetics of intraperitoneally-administered monoclonal antibodies: I. Transdiaphragmatic blockade of the terminal lymphatics in the rat.

Recent studies on the intraperitoneal administration of radiolabeled monoclonal antibodies indicate that the diaphragm and, in particular, the lymphatics associated with the diaphragm are more involved in the transport of such high-molecular-mass moieties than was earlier suspected. The current study examines the role of the diaphragm in the i.p. transport of an IgG2a murine monoclonal antibody, 5G6.4, by observing the effect on the absorption of the antibody produced when the diaphragm has been scarred. Normal, sham-operated, and diaphragmatically scarred (abrasions made with 600-grade sandpaper) female Sprague Dawley rats (150-250 g) were administered intraperitoneal injections of 125labeled 5G6.4 in a volume of 2.0 cm3. Approximately 5 micrograms antibody protein was administered in the individual 19-microCi injections per rat. Scarring was effective in partially blocking the amount of labeled antibody that crossed the diaphragm. Mean diaphragm levels (% injected dose/g) of 125I-labeled 5G6.4 from the scarred group were 16.8% lower than values from the sham-operated rats and 37.2% lower than those from the control rats. The blockade was effective in slowing the appearance of the labeled antibody in the systemic circulation. The half-time to absorption was significantly prolonged in the scarred group; mean t1/2 absorption values of 2.5 h for the control group, 5.3 h for the sham-operated group, and 9.6 h for the diaphragmatically blocked group were recorded. Scarring the diaphragm reduced the mean maximum blood concentration by 27.6% over the control group and 23.9% over the sham-operated group. The mean time to maximum blood concentration was lengthened by 93..0% over the control group and 35.3% over the sham-operated group due as a result of scarification. Presumably this impedence to absorption would increase the time that the radiolabeled antibody bathed the peritoneal space. The scarred group also had the largest "system mean residence time" (162.5 h) compared to the sham-operated (147.9 h) and control (118.7 h) groups. These values further verify the effect of surgery on the kinetics of the i.p. administered radiolabeled monoclonals. This work demonstrates that scarifying the diaphragm does alter the kinetics of the i.p. administered monoclonal antibodies and supports the concept that transdiaphragmatic lymphatic absorption is an important route of antibody clearance from the peritoneal cavity.

Absorption

Development of morphologic, hemodynamic, and biochemical changes in lungs of rats given monocrotaline pyrrole.

A single, intravenous administration of a low dose of monocrotaline pyrrole (MCTP), a derivative of the pyrrolizidine alkaloid monocrotaline (MCT), induces progressive pulmonary hypertension and right ventricular hypertrophy (RVH) in rats. The temporal relationship between morphologic alterations, biochemical markers of lung injury, and the development of pulmonary hypertension was determined during the developing pulmonary disease. Three days after a single iv injection of 3.5 mg/kg MCTP, small increases in bronchoalveolar lavage (BAL) fluid lactate dehydrogenase (LDH) activity and accumulation in the lungs of intravenously administered 125I-bovine serum albumin (BSA) were associated with minimal to mild interstitial edema around large airways and blood vessels. By Day 5, BAL fluid LDH activity and 125I-BSA accumulation had increased further, and lung weight/body weight ratio and BAL fluid protein concentration were greater than those of control. Interstitial edema was more pronounced and involved patches of alveolar septal walls. A mild increase in numbers of mononuclear cells, including hypertrophied interstitial cells, was evident in these areas. Walls of pulmonary arteries less than 60 microns in diameter were mildly thickened. By Day 8, scattered clusters of alveolar sacs contained serous exudate, and interstitial mononuclear infiltrates were more pronounced. Mild to moderate thickening of arterial walls was apparent in small and large vessels. By Day 14, pulmonary arterial pressure was elevated and RVH was evident. Arterial walls were thickened and had hypertrophy of medial smooth muscle cells and intercellular edema, which was particularly prominent in areas with perivascular interstitial inflammation. Large patches of lung interstitium and alveolar lumens contained serous or fibrinous exudate. In summary, a single, intravenous administration of MCTP induced a delayed and progressive pulmonary microvascular leak, interstitial inflammation, and alterations in muscular blood vessels which resulted in pulmonary hypertension within 14 days. These morphologic, biochemical, and hemodynamic changes are nearly identical to alterations induced by the parent alkaloid, MCT.

Animals

Estimation of the amount of alcohol ingested from a single blood alcohol concentration.

Capillary blood alcohol concentrations (BAL) measured in 22 young adult male volunteers each of whom received three different treatments of alcohol (total N = 66) have been related quantitatively to the dose of alcohol ingested. Linear regression with reasonably homogeneous variances have been found when the BAL at 2, 2.5 and 3 hr are divided by the person's body weight and plotted versus the g/kg (D/W) dose. Error analysis indicated that the least error in the predicted dose (D/W) was obtained for BAL measured at 2 hr post dosing. In the latter case the mean absolute error was 6.23%, 59% of the errors were within +/- 5% and 88% of the errors were within +/- 10%.

Adult

Effects of altered platelet number on pulmonary hypertension and platelet sequestration in monocrotaline pyrrole-treated rats.

To study the role of platelets in monocrotaline pyrrole (MCTP)-induced pulmonary hypertension, pulmonary sequestration of 111In-labeled platelets in rats treated with MCTP and anti-rat platelet serum (PAS) was examined. Lung injury from a single, intravenous injection of MCTP (3.5 mg/kg) at Day 8 was evident as elevated lung weight and lavage fluid protein and lactate dehydrogenase activity. Additionally, right ventricular hypertrophy and elevated pulmonary arterial pressures (PAP) occurred. Treatment with PAS on Days 6-8 did not affect the lung injury but resulted in an attenuation of the pulmonary hypertensive response. Pulmonary platelet sequestration was also decreased in PAS-treated rats, yet the sequestration in the lungs of MCTP-treated rats that received PAS was significantly higher than that in the lungs of N,N-dimethylformamide (DMF) controls. MCTP-treated rats receiving control serum (CS) tended to sequester more 111In-labeled platelets than respective DMF controls, but this was not statistically significant. Blood platelet half-life was unaltered in rats receiving CS. When rats were treated similarly with MCTP and PAS and were killed at 18 days, the attenuation of the pulmonary hypertensive response previously described was not observed, and lung injury was more extensive than when CS was given. Apparently, platelet depletion delayed the development of the pulmonary hypertensive response. Supranormal platelet numbers produced by splenectomy did not affect MCTP-induced lung injury or the elevation in PAP. These results support the hypothesis that the development of MCTP-induced pulmonary hypertension is mediated in part by platelets.

Animals

Gas chromatographic determination of gallopamil and norgallopamil in human plasma.

A highly sensitive gas chromatographic assay is described for the simultaneous determination of gallopamil, a calcium channel blocking agent, and its major metabolite, norgallopamil. A multi-step extraction procedure is employed followed by on-column capillary gas chromatographic analysis using nitrogen-selective detection. Acetylation of norgallopamil is performed to enable accurate quantification of the metabolite. Linearity was achieved over the range 1-50 ng/ml for both analytes. Assay specificity, precision and accuracy were investigated.

Chemical Phenomena