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Biomedical subjects

M Mullen

Publications and source records attributed to M Mullen.

At least 19 recordsLinked to original sources
PubMed1995

Harvesting and enrichment of hematopoietic progenitor cells mobilized into the peripheral blood of normal donors by granulocyte-macrophage colony-stimulating factor (GM-CSF) or G-CSF: potential role in allogeneic marrow transplantation.

To explore the use of stem/progenitor cells from peripheral blood (PB) for allogeneic transplantation, we have studied the mobilization of progenitor cells in normal donors by growth factors. Normal subjects were administered either granulocyte-macrophage colony-stimulating factor (GM-CSF) at 10 micrograms/kg/d, or G-CSF at 10 micrograms/kg/d, or a combination of G- and GM-CSF at 5 micrograms/kg/d each, administered subcutaneously for 4 days, followed by leukapheresis on day 5. Mononuclear cells expressing CD34 (CD34+ cells) were selectively enriched by affinity labeling using Dynal paramagnetic microspheres (Baxter Isolex; Baxter Healthcare Corp, Santa Ana, CA). The baseline CD34+ cells in peripheral blood before mobilization was 0.07% +/- 0.05% (1.6 +/- 0.7/microL; n = 18). On the fifth day after stimulation (24 hours after the fourth dose), the CD34+ cells were 0.99% +/- 0.40% (61 +/- 14/microL) for the 8 subjects treated with G-CSF, 0.25% +/- 0.25% (3 +/- 3/microL, both P < .01 v G-CSF) for the 5 subjects administered GM-CSF, and for the 5 subjects treated with G- and GM-CSF, 0.65% +/- 0.28% (41 +/- 18/microL, P < .5 v GM-CSF). Parallel to this increase in CD34+ cells, clonogenic assays showed a corresponding increase in CFU-GM and BFU-E. The total number of CD34+ cells collected from the G-CSF group during a 3-hour apheresis was 119 +/- 65 x 10(6) and was not significantly different from that collected from the group treated with G- and GM-CSF (101 +/- 35 x 10(6) cells), but both were greater than that from the group treated with GM-CSF (12.6 +/- 6.1 x 10(6); P < .01 for both comparisons). Analysis of the CD34+ subsets showed that a significantly higher percentage of cells with the CD34+/CD38- phenotype is found after mobilization with G- and GM-CSF. In the G-CSF group, immunomagnetic selection of CD34+ cells permitted the enrichment of the CD34+ cells in the apheresis product to 81% +/- 11%, with a 48% +/- 12% yield and to a purity of 77% +/- 21% with a 51% +/- 15% recovery in the G- and GM-CSF group. T cells were depleted from a mean of 4.5 +/- 2.0 x 10(9) to 4.3 +/- 5.2 x 10(6) after selection, representing 99.9% depletion. We conclude that it is feasible to collect sufficient numbers of PB progenitor cells from normal donors with one to two leukapheresis procedures for allogeneic transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Effects of a behavioral weight loss program stressing calorie restriction versus calorie plus fat restriction in obese individuals with NIDDM or a family history of diabetes.

OBJECTIVE: The aim of this randomized trial was to compare the effects of a behavioral intervention focusing on either calorie restriction alone or calorie plus fat restriction on weight loss and changes in lipids and glycemic control in individuals with non-insulin-dependent diabetes mellitus (NIDDM) or a family history of diabetes. RESEARCH DESIGN AND METHODS: We recruited 44 obese women with NIDDM and 46 obese women with a family history of NIDDM and randomly assigned these subjects to calorie restriction (CAL) or to calorie plus fat restriction (CAL + FAT). All subjects participated in a 16-week behavioral weight loss program, with training in diet, exercise, and behavior modification. Subjects assigned to the CAL condition were given a 1,000-1,500 kcal/day goal and self-monitored calories consumed. Subjects assigned to the CAL+FAT condition had the same calorie goal, but were also given a fat goal (grams of fat/day), to produce a diet with < 20% of calories from fat; this group monitored both calories and fat grams. RESULTS: Among NIDDM subjects, weight loss of the subjects in the CAL+FAT condition was significantly greater than subjects in the CAL condition (7.7 vs. 4.6 kg) and the CAL+FAT condition group also maintained their weight loss better at the 1-year follow-up (5.2 vs. 1.0 kg). Significant decreases in glucose, high-density lipoprotein (HDL) cholesterol, and total cholesterol were seen after 16 weeks of treatment among NIDDM subjects; these changes were similar in CAL and CAL+FAT groups, but a greater proportion of subjects in CAL condition required oral hypoglycemic medication. At the 1-year follow-up, all parameters had returned to baseline. No significant differences in weight loss or physiological changes were seen between CAL and CAL+FAT conditions in subjects with a family history of diabetes. CONCLUSIONS: These results suggest that using the combination of calorie and fat restriction may help promote weight loss in obese NIDDM patients. No other long-term benefits of this regimen were observed.

Behavior Therapy↗
PubMed1994

A meta-analysis of the effect of oral and inhaled corticosteroids on growth.

This analysis summarizes studies comparing attained heights with expected heights of children with asthma treated with inhaled or oral corticosteroids. The possible moderating effects of treatment duration, and dosage and asthma severity are also examined. A preliminary database of 95 articles rendered 21 includable studies representing 810 patients with asthma, which yielded 29 tests of the corticosteroid-growth effect. Statistical integration of the results of these studies revealed a significant but small tendency for corticosteroid therapy in general to be associated with diminished final height (Z = 2.328, p = 0.01, mean r = -0.023). However, this effect varied for the specific drugs under consideration. As expected, significant weak growth impairment was observed for prednisone (Z = 2.137, p = 0.0164, mean r = -0.295) and "other oral corticosteroids" (Z = 9.107, p = 2.44E-18, mean r = -0.260). On the other hand, a significant moderate tendency was observed for inhaled beclomethansone dipropionate therapy to be associated with attaining normal stature (Z = 7.395, p = 2.17E-13, mean r = +0.432). There was no statistical evidence for beclomethasone dipropionate therapy to be associated with growth impairment at higher doses, for longer therapy durations, or among patients with more severe asthma. This meta-analytic integration indicates that available studies of inhaled beclomethasone dipropionate therapy do not show an association between its use and the adverse effect of diminished stature.

Administration, Inhalation↗
PubMed1994

Localised pulmonary resection for bronchiectasis in hypogammaglobulinaemic patients.

BACKGROUND: Bronchiectasis and pulmonary infections are common in patients with hypogammaglobulinaemia. Despite intravenous gammaglobulin treatment and appropriate antibiotics, a subgroup of patients remains with persistent localised pulmonary infection in segments where bronchiectasis had developed before appropriate treatment. As such localised pulmonary suppuration (segmental or lobar) may serve as a focus for progression of bronchiectasis, surgical resection of the involved segments may be considered. The outcome of pulmonary resection in four such patients is reported. RESULTS: Surgery was well tolerated except for one postoperative empyema. Information on follow up is available from 3.5 to 5 years. All patients experienced considerable reduction of symptoms including cough, sputum production, antibiotic use, and hospital admissions. CONCLUSIONS: Surgical resection of localised bronchiectatic segments should be considered in patients with hypogammaglobulinaemia with persistent localised suppuration and symptoms refractory to medical treatment.

Adolescent↗
PubMed1994

Symptom severity and utilization of treatment resources among dually diagnosed inpatients.

OBJECTIVE: The author's goal was to determine the clinical characteristics of patients admitted to an acute voluntary psychiatric unit with a dual diagnosis treatment program. METHODS: A total of 104 consecutive patients admitted the unit were divided into three groups based on whether they had a current substance use disorder, a past substance use disorder, or no substance use disorder. On the basis of data derived from extensive structured interviews, the three groups' demographic characteristics, severity of symptoms, and utilization of psychiatric and alcohol and drug treatment services were compared. RESULTS: The dually diagnosed patients in the sample were more likely to have a mood disorder, and the patients without a substance use disorder were more likely to have a diagnosis of schizophrenia or mania. Patients with a current substance use disorder had more severe symptoms and used more treatment resources than patients in other groups. Patients with a past substance use disorder also had increased symptom severity, with measures of severity about halfway between those of patients with current substance use disorder and those of patients with no substance use disorder. CONCLUSIONS: Psychiatric patients with a past substance use disorder, like those with a current substance use disorder, may be at risk for increased symptom severity and increased utilization of treatment resources and may need specialized treatment planning. The needs of dually diagnosed patients with mood disorders as well as those with chronic psychotic conditions should be considered in local and national mental health care planning.

Adult↗
PubMed1994

Reinfusion and serial measurements of carboplatin-mobilized peripheral-blood progenitor cells in patients receiving multiple cycles of high-dose chemotherapy.

PURPOSE: To examine the ability of carboplatin to mobilize peripheral-blood progenitor cells (PBPCs) and to examine the impact of infusing these cells on myelosuppression following multiple cycles of high-dose therapy. Fluctuations in circulating progenitor cell concentration following repeated cycles of this therapy were also measured. PATIENTS AND METHODS: Eight patients received a total of 20 cycles of carboplatin 1,200 mg/m2 per course, granulocyte-macrophage colony-stimulating factor (GM-CSF) 5 micrograms/kg/d, and PBPC reinfusion every 28 days. PBPC were collected following 1 week of GM-CSF and following the first and second cycles of chemotherapy. Hematologic toxicity was correlated with the number of progenitor cells reinfused per cycle. The concentration of PBPC per milliliter of blood was measured at study entry, following GM-CSF priming, and after each cycle of chemotherapy. RESULTS: We observed a strong inverse correlation between the number of PBPCs (CD34 and colony-forming unit granulocyte-macrophage [CFU-GM]), but not mononuclear cells (MNCs) reinfused and the days with neutropenia less than 500/microL and platelets less than 20,000/microL. Compared with baseline levels, the circulating PBPC concentration increased up to 27-fold following the first course of chemotherapy, but decreased toward, and eventually below, baseline following the second and third cycles of carboplatin. CONCLUSION: PBPC reinfusion directly correlated with a reduction in myelosuppression following high-dose carboplatin chemotherapy. While high-dose carboplatin plus GM-CSF leads to a substantially greater mobilization of PBPC than GM-CSF alone, this effect is lost after multiple treatment cycles. These results emphasize the importance of early procurement and value of PBPC reinfusion in conjunction with multiple cycles of dose-intensive chemotherapy.

Adult↗
PubMed1993

The association between beta-agonist use and death from asthma. A meta-analytic integration of case-control studies.

OBJECTIVES: The purpose of this investigation was to provide an empirical summary of the evidence regarding the association between beta-agonist use and death from asthma. This effort integrated the results of case-control studies that examined the use of beta-agonists among asthmatic patients who died and the use of beta-agonists among asthmatic patients who did not die. The possible moderating effects of patient sample age and mode of delivery (oral, metered-dose inhaler, and nebulizer) were also examined. DATA SOURCES: An on-line computer search (using MEDLINE) was conducted using the key words beta-agonist and asthma. This search was supplemented by ancestry and descendency approach searches. Studies that were available as of April 1992 were eligible for inclusion in this integration. STUDY SELECTION: Studies were included if they reported the precise numbers of cases and controls who did and did not use a beta-agonist. A total of six case-control studies comprising 15 separate tests of the relation between beta-agonist use and death from asthma and data for 364 cases and 1388 controls were included. DATA EXTRACTION: The 2 (case vs control) x 2 (did vs did not use beta-agonist) designs allowed for direct derivation of a chi 2 statistic that tested the association between beta-agonist use and death from asthma. Mode of delivery and average age of sample were also coded. DATA SYNTHESIS: Statistical integration revealed a significant, although extremely weak, relation between beta-agonist use and death from asthma (z = 3.996; P = .000075; mean r = .055). This relation emerged only when beta-agonists were administered with a nebulizer (z = 4.481; P = .0000038; mean r = .103). There was no association between beta-agonist use and death when beta-agonists were administered by metered-dose inhaler (z = 1.194; P = .11; mean r = .031) or orally (z = 1.247; P = .1; mean r = .031). Adults were more likely than adolescents to evidence the association between beta-agonist use and death. CONCLUSIONS: These results document the extremely small magnitude of the relation between beta-agonist use and death from asthma. Furthermore, these results specify that the weak relation between beta-agonist use and death from asthma may really be restricted to the delivery of beta-agonists with a nebulizer. These findings suggest that the headlines that followed the report by Spitzer et al (1992) were misleading.

Administration, Inhalation↗
PubMed1993

Effects on food cravings of a very low calorie diet or a balanced, low calorie diet.

It is commonly believed that dieting and the restriction of specific types of foods produces cravings for these foods. This study, therefore, compared changes in self-reported cravings experienced by 93 obese subjects with Type II diabetes who were randomly assigned to behavioral treatment programmes which used either: (a) a balanced, low-calorie diet (LCD) of 1000-1200 kcal/day throughout, with all foods allowed in moderation, or (b) a programme which included a 12-week period of a very low calorie diet (VLCD), where intake was restricted to 400 kcal/day with only lean meat, fish, or fowl allowed. There were significant decreases in cravings for all types of foods over the 20 weeks of the study for both the VLCD and the LCD conditions. The decreases in cravings were particularly pronounced for the VLCD condition for low-fat, high-protein foods (the only foods allowed on the VLCD) and for complex carbohydrates, especially grains (one of the types of foods prohibited on this diet). There was no evidence to support the belief that restricting intake of certain foods leads to increased craving for these foods or that the magnitude of weight loss is related to food cravings.

Adult↗
PubMed1993

High-dose carboplatin chemotherapy with GM-CSF and peripheral blood progenitor cell support: a model for delivering repeated cycles of dose-intensive therapy.

High-dose chemotherapy regimens can cure a number of otherwise incurable diseases, such as Hodgkin's disease, non-Hodgkin's lymphoma, neuroblastoma, acute leukemia (in remission), and breast cancer. Trials of high-dose chemotherapy have generally used autologous bone marrow transplant or peripheral blood stem cell support to ensure hematologic recovery after intensive chemotherapy and/or radiation. This report describes an approach in which high-dose carboplatin chemotherapy was followed initially by granulocyte-macrophage colony-stimulating factor (GM-CSF; Escherichia coli. Sandoz-Schering, East Hanover and Kenilworth, NJ) and in subsequent patients, by both GM-CSF and repeated cycles of peripheral blood progenitor cell (PBPC) collection and administration. The addition of PBPC to this regimen led to significant reductions in the duration of neutropenia and thrombocytopenia, the requirement for erythrocyte and platelet transfusions, the length of hospital stay, and the use of intravenous antibiotics in this group relative to those patients who received GM-CSF alone. In addition, laboratory studies are presented that show a direct correlation between the number of progenitor cells reinfused and the duration of neutropenia and thrombocytopenia. The report also reviews data indicating that circulating progenitor cells are depleted by this approach. This suggests that the number of progenitor cells available for mobilization is finite. Finally, the magnitude of these effects, and their implications for future trials with repetitive cycles of dose-intensive therapy, are discussed.

Adult↗
PubMed1993

Strengthening behavioral interventions for weight loss: a randomized trial of food provision and monetary incentives.

Behavioral treatments for obesity seek to modify eating and exercise behaviors by a change in their antecedents and consequences. More direct modification of antecedents and consequences by (a) the provision of food to patients and (b) the provision of financial rewards for weight loss was hypothesized to improve treatment outcomes. Two hundred two men and women were randomly assigned to no treatment, standard behavioral treatment (SBT), SBT plus food provision, SBT plus incentives, or SBT plus food provision and incentives. The major finding was that food provision significantly enhanced weight loss. Weight losses with SBT averaged 7.7, 4.5, and 4.1 kg at 6, 12, and 18 months, respectively, compared with 10.1, 9.1, and 6.4 kg, respectively, at the same intervals with the addition of food. Food provision also enhanced attendance, completion of food records, quality of diet, and nutrition knowledge. We conclude that the provision of food to weight-loss patients is a promising methodology that deserves further exploration.

Adult↗
PubMed1992

Sequential cycles of high-dose carboplatin administered with recombinant human granulocyte-macrophage colony-stimulating factor and repeated infusions of autologous peripheral-blood progenitor cells: a novel and effective method for delivering multiple courses of dose-intensive therapy.

PURPOSE: The trial was undertaken to study the effect of administering granulocyte-macrophage colony-stimulating factor (GM-CSF) with and without peripheral-blood progenitor cells (PBPC) on the hematologic and nonhematologic toxicity observed with multiple cycles of high-dose carboplatin chemotherapy. PATIENTS AND METHODS: Eighteen patients with a variety of solid tumors received a total of 40 cycles of carboplatin, 1,200 mg/m2 per cycle, administered by continuous infusion over 96 hours. All 40 courses were administered with a daily 4-hour intravenous (IV) infusion of either 5 or 10 micrograms/kg/d of recombinant human Escherichia coli-derived GM-CSF. The first 20 courses were administered without PBPC support (treatment A). Because of severe neutropenia and thrombocytopenia, the next 20 courses of therapy were administered with GM-CSF, PBPC, and oral antibiotic prophylaxis (treatment B). RESULTS: The addition of PBPC support led to a significant reduction in the duration of neutropenia (10.5 v 7.5 days; P = .027) and thrombocytopenia (12.4 v 5.2 days; P = .001), number of RBC transfusions (six v three; P = .01) and platelet transfusions (10.3 v 3.7; P = .013), number of hospital days (12.6 v 2.9; P = .01), and days of IV antibiotics (11.8 v 2.4; P = .007) per cycle. Significant increases in the weekly dose intensity (206 v 285 mg/m2/wk; P = .014) and total dose (2,287 v 3,600 mg/m2; P = .018) of carboplatin delivered were also observed with treatment B. The overall response rate in this study was 70%, with 11 of 16 assessable patients achieving either a complete (three patients) or partial (eight patients) remission. CONCLUSION: This combination of GM-CSF and PBPC infusion represents an effective method for delivering multiple cycles of high-dose carboplatin chemotherapy and may serve as a model for the administration of high-dose chemotherapy in future trials.

Adult↗
PubMed1992

A dose-escalation study of carboplatin/cyclophosphamide/etoposide along with autologous bone marrow or peripheral blood stem cell rescue.

Twenty patients have received 21 courses of high-dose cyclophosphamide (6 g/m2 over 4 days), etoposide (1,800 mg/m2 over 3 days), and carboplatin (800 to 1,600 mg/m2 by continuous infusion over 96 hours) and autologous bone marrow or peripheral blood stem cell rescue. The maximum tolerated dose of this regimen included these doses of cyclophosphamide and etoposide with a total of 1,600 mg/m2 carboplatin. Acute renal failure was the dose-limiting toxicity and, at the maximum tolerated dose, was observed in two patients of 14 evaluable courses. Nonhematologic toxicity was otherwise modest, and the overall response rate was 70% in patients with a wide variety of solid hematologic neoplasms.

Acute Kidney Injury↗
PubMed1991

Alcohol counseling in a general medicine clinic. A randomized controlled trial of strategies to improve referral and show rates.

We conducted a controlled trial of two interventions to increase the number of patients receiving alcohol counseling in an academic, general medicine clinic. Ongoing randomization yielded similar groups of patients and providers. By applying a two-item alcoholism-screening instrument incorporated into the routine intake process, nursing staff were successful in screening 90.4% of the 1,328 eligible patients seen during a 4-month study period. Of the patients screened, 428 (35.6%) were found to be positive. In those groups where nurses were allowed to refer directly on the basis of a positive screening result, over four times as many patients (10.8% versus. 2.3%) accepted appointments for counseling, as did patients seen by physicians providing standard care. Patients who were briefly introduced to the alcohol counselor at the time referral were no more likely to keep their first, formal appointments than were patients scheduled in the usual manner. Patients who did receive counseling had their diagnoses confirmed by the 25-item Michigan Alcoholism Screening Test. We conclude that the adoption of an alcohol screening program in our clinic increased the number of patients appropriately referred for counseling.

Alcoholism↗
PubMed1988

High-pressure pulsation of central and microvessel pulmonary artery endothelial cells.

We developed an in vitro method of pulsating central and microvessel pulmonary artery endothelial cells that would allow us to study the effects of increased distending pressures over a prolonged period of time. Preservation of the contact-inhibited monolayer was assessed on phase contrast microscopy and, in addition, scanning and transmission electron microscopy (SEM, TEM) were used to determine whether there were alterations in the surface characteristics or intracytoplasmic organelles that suggested cellular damage. The cells used were obtained from Rambouillet lambs, age 3-5 days, anesthetized with halothane and ventilated. The endothelium was harvested from the central pulmonary artery (CPA) by scraping the luminal surface and from the microvessels (MPA) by infusing microcarrier beads 40-140 microns external diameter. After the second passage in culture, the cells were seeded onto the translucent, flexible polyvinylchloride membrane of a transducer dome and grown to confluence. The cell dome was then connected to a blank dome with an attached quartz transducer, to a reservoir, and to stainless steel bellows tubing, all filled with culture medium and affixed to a pulsation generator. By varying the height of the reservoir, the amplitude of excursion of the bellows tubing, and the rate, the cells could be pulsated at a given distending pressure and frequency. Confluent CPA endothelial cells from three lambs and MPA cells from two others were studied after pulsation at both 100/60 and 20/10 mmHg, 60 times/min for 48 h and after nonpulsation. On phase contrast light microscopy and on SEM, the cells remained confluent.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Angiotensin II prevents hypoxic pulmonary hypertension and vascular changes in rat.

Angiotensin II, a vasoconstrictor, has been previously demonstrated to produce a secondary vasodilatation due to release of prostaglandins. Because of this effect, we investigated whether infusion of exogenous angiotensin II via miniosmopumps in rats during a 1-wk exposure to chronic hypobaric hypoxia might prevent pulmonary hypertension, right ventricular hypertrophy, and vascular changes. We instrumented the rats with indwelling cardiovascular catheters and compared the hemo-dynamic and structural response in animals given angiotensin II, indomethacin in addition to angiotensin II (to block prostaglandin production), or saline with or without indomethacin. We then determined whether angiotensin II infusion also prevents acute hypoxic pulmonary vasoconstriction. We observed that exogenous angiotensin II infusion abolished the rise in pulmonary artery pressure, the right ventricular hypertrophy, and the vascular changes induced during chronic hypoxia in control saline-infused rats with or without indomethacin. The protective effect of angiotensin II was lost when indomethacin was given to block prostaglandin synthesis. During acute hypoxia, both angiotensin II and prostacyclin infusions similarly prevented the rise in pulmonary artery pressure observed in saline-infused rats and in rats given indomethacin or saralasin in addition to angiotensin II. Thus exogenous angiotensin II infusion prevents chronic hypoxic pulmonary hypertension, associated right ventricular hypertrophy, and vascular changes and blocks acute hypoxic pulmonary hypertension, and this is likely related to its ability to release vasodilator prostaglandins.

Acute Disease↗
PubMed1986

Effect of intravenous papain on tracheal pressure-volume curves in rabbits.

To investigate the effects of airway cartilage softening on tracheal mechanics, pressure-volume (PV) curves of excised tracheas were studied in 12 rabbits treated with 100 mg/kg iv papain, whereas 14 control animals received no pretreatment. The animals were killed 24 h after the injection and the excised specimens studied 24 h later. Treated tracheas exhibited decreased ability to withstand negative transmural pressures, reflected in increased collapse compliance: 6.2 +/- 2.1 vs. 2.0 +/- 0.5% peak volume (Vmax)/cmH2O means +/- SD, P less than 0.001, (Vmax = extrapolated maximal tracheal volume), increased kc (exponential constant that reflects the shape of collapse limb of the PV curve): 0.244 +/- 0.077 vs. 0.065 +/- 0.015 (P less than 0.001). The distension limb of the PV curve greater than 2.5 cmH2O transmural pressure (Ptm) was no different. Compliance between 0 and 2.5 cmH2O Ptm was increased in papain-treated rabbits: 4.97 +/- 1.73 vs. 2.30 +/- 0.31% Vmax/cmH2O (P less than 0.001). Tracheal volume, and therefore mean diameter, was decreased at 0 Ptm: 2.7 +/- 0.26 vs. 3.2 +/- 0.27 mm (P less than 0.001). We conclude that airway cartilage softening increases the compliance of the trachea at pressures less than 2.5 cmH2O Ptm.

Animals↗
PubMed1985

Pulmonary toxicity of monocrotaline differs at critical periods of lung development.

We injected 3-day-old (neonatal), 8-day-old (infant), and 8-wk-old (adult) Sprague-Dawley rats with monocrotaline to examine the effect of a toxic agent at various stages of lung development. Two and four weeks after injection the rats were killed and the heart and lungs removed: the right and left ventricles were separated and weighed, the pulmonary artery was injected with barium-gelatin, and the lung was fixed in the inflated state. Morphometric techniques were applied to assess lung volume, alveolar size and number, and arterial size, muscularity, and concentration relative to alveolar. Rats injected with monocrotaline in the neonatal period did not survive to 3 wk. After 2 wk, there was no significant right ventricular hypertrophy and pulmonary vascular changes were no worse than in the other rat groups injected with monocrotaline, but alveolar development was severely impaired; less than one-third the normal number was present. Rats injected with monocrotaline in infancy had normal alveolar development. After 2-wk, the arterial changes, i.e. extension of muscle into peripheral arteries, medial hypertrophy of muscular arteries, and decreased arterial concentration relative to alveolar were similar to those observed in adult rats. After 4 wk, there was a decrease in medial hypertrophy associated with growth in artery size and only a lack of regression of right ventricular weight. In adult rats, after 4 wk medial hypertrophy became progressively more severe, the arterial concentration relative to alveolar decreased further, and right ventricular hypertrophy developed.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗