Comparison of ultrashort-lived iridium-191m with technetium-99m for first pass radionuclide angiocardiographic evaluation of right and left ventricular function in adults.

Ultrashort-lived iridium-191m (Ir-191m, physical half-life = 5.0 seconds) has been used in angiocardiography, primarily in pediatric patients. A theoretical obstacle to more widespread use of Ir-191m is the belief that its physical half-life is too short to permit evaluation of left ventricular function in adult patients. To evaluate its usefulness in adults, first pass ejection fractions of the left and right ventricles determined with use of Ir-191m and technetium-99m (Tc-99m) were compared in 33 adult patients. An osmium-191m----iridium-191m (Os-191----Ir-191m) generator was employed to deliver doses of 150 to 250 mCi (5.5 to 9.2 GBq) of Ir-191m for intravenous injection. The whole body radiation absorbed dose with Ir-191m was 15 to 25 mrad. High quality angiocardiograms were obtained with both Tc-99m and Ir-191m. Total counts per image for the right ventricle were 51,000 +/- 8,000 (mean +/- SD) for Ir-191m and 30,000 +/- 8,000 for Tc-99m. The left ventricular counts were comparable for both radiotracers (25,000 +/- 7,000 for Ir-191m and 25,000 +/- 8,000 for Tc-99m). Right ventricular ejection fractions were similar: 44 +/- 8% for Ir-191m and 47 +/- 9% for Tc-99m. The correlation coefficient was 0.93 with a standard deviation of the regression of 3.1% ejection fraction units. The left ventricular ejection fractions were also similar: 45 +/- 14% for Ir-191m and 46 +/- 13% for Tc-99m. The left ventricular ejection fraction correlation coefficient was 0.96 with a standard deviation of the regression of 3.7%.(ABSTRACT TRUNCATED AT 250 WORDS)

An osmium-191/iridium-191m radionuclide generator using an oxalato osmate parent complex.

A new osmium-191/iridium-191m (191Os/191mIr) radionuclide generator has been developed that offers high 191mIr yield (greater than 20%/ml) and low 191Os breakthrough (less than 5 X 10(-4)%/ml) when eluted with a solution of 0.001 M oxalic acid and 0.9% (normal) saline. This is the first 191Os/191mIr generator that combines the advantages of high 191mIr yield, extremely low 191Os breakthrough, and an eluate that does not require buffering prior to injection. These improvements in performance were accomplished through use of the chelate transdioxobisoxalatoosmate(VI) as the parent complex on the generator. The clinical result of the combination of higher yield and lower breakthrough is a 100-fold decrease in the estimated patient radiation dose compared with the same study performed with technetium-99m (99mTc), and the injectable eluate makes the generator easier to use. Acute and subacute toxicity studies performed on this generator eluate have shown no adverse effects attributable to the eluate.

Surveillance bronchoscopy in lung transplant recipients.

STUDY OBJECTIVES: To establish whether a consensus exists among active transplant centers regarding the use and interpretation of information obtained by surveillance bronchoscopic lung biopsy (SBLB). DESIGN: Prospective standardized questionnaire answered via mail and telephone communications. PARTICIPANTS: A five page, 18-question survey was sent to all lung transplant programs listed by the United Network of Organ Sharing in North America, as well as eight selected international programs. Ninety-one surveys were sent to 83 North American and eight international programs. Seventy-four programs (81%) responded. Seventeen programs (19%) were excluded secondary to inactivity. The remaining 57 programs (63%) were included in final data analysis. INTERVENTIONS: None. RESULTS: Sixty-eight percent (39/57) of the responding programs perform SBLBs. Ninety-two percent of the programs performing SBLBs do so within the first month, and 69% continue to do so on a regular basis. Sixty-nine percent (27/39) of programs performing SBLBs continue to do so after 1 year. Eighty-six percent (32/37) of respondents believe that SBLB impacts on patient management at least 10% of the time. Technically, 90% (35/39) take biopsy specimens from more than one lobe per SBLB session. Fifty-nine percent (23/39) took 6 to 10 biopsy specimens per session, 33% (13/39) took three to five biopsy specimens, and 7% (4/39) took > 10 biopsy specimens per session. Eighty-six percent (32/37) of the responding centers reported treating asymptomatic rejection at grade 2A, while 14% (5/37) waited until histologic grade 3A before beginning treatment. Complications from SBLB were minimal with < 5% rates of pneumothorax, requirement for chest tube placements, or significant bleeding during SBLB reported by > 95% of the programs performing SBLB. CONCLUSIONS: Most active lung transplant centers perform SBLBs and do so on a regular basis. However, a wide range of opinion exists over the utility and technique of SBLB and the impact of its results influencing outcome in the lung transplant recipient. To answer these questions, a randomized multicentered trial or registry to determine the effect of SBLB on lung transplant recipient morbidity and mortality is required.

Improvements in lung function, exercise, and quality of life in hypercapnic COPD patients after lung volume reduction surgery.

STUDY OBJECTIVE: To determine the impact of preoperative resting hypercapnia on patient outcome after bilateral lung volume reduction surgery (LVRS). METHODS: We prospectively examined morbidity, mortality, quality of life (QOL), and physiologic outcome, including spirometry, gas exchange, and exercise performance in 15 patients with severe emphysema and a resting PaCO2 of > 45 mm Hg (group 1), and compared the results with those from 31 patients with a PaCO2 of < 45 mm Hg (group 2). RESULTS: All preoperative physiologic and QOL indices were more impaired in the hypercapnic patients than in the eucapnic patients. The hypercapnic patients exhibited a lower preoperative FEV1, a lower diffusing capacity of the lung for carbon monoxide, a lower ratio of PaO2 to the fraction of inspired oxygen, a lower 6-min walk distance, and higher oxygen requirements. However, after surgery both groups exhibited improvements in FVC (group 1, p < 0.01; group 2, p < 0.001), FEV1 (group 1, p=0.04; group 2, p < 0.001), total lung capacity (TLC; group 1, p=0.02; group 2, p < 0.001), residual volume (RV; group 1, p=0.002; group 2, p < 0.001), RV/TLC ratio (group 1, p=0.03; group 2, p < 0.001), PaCO2 (group 1, p=0.002; group 2, p=0.02), 6-min walk distance (group 1, p=0.005; group 2, p < 0.001), oxygen consumption at peak exercise (group 1, p=0.02; group 2, p=0.02), total exercise time (group 1, p=0.02; group 2, p=0.02), and the perceived overall QOL scores (group 1, p=0.001; group 2, p < 0.001). However, because the magnitude of improvement was similar in both groups, and the hypercapnic group was more impaired, the spirometry, lung volumes, and 6-min walk distance remained significantly lower post-LVRS in the hypercapnic patients. There was no difference in mortality between the groups (p=0.9). CONCLUSIONS: Patients with moderate to severe resting hypercapnia exhibit significant improvements in spirometry, gas exchange, perceived QOL, and exercise performance after bilateral LVRS. The maximal achievable improvements in postoperative lung function are related to preoperative level of function; however, the magnitude of improvement can be expected to be similar to patients with lower resting PaCO2 levels. Patients should not be excluded from LVRS based solely on the presence of resting hypercapnia. The long-term benefit of LVRS in hypercapnic patient remains to be determined.

Bilateral apical vs nonapical stapling resection during lung volume reduction surgery.

STUDY OBJECTIVES: To determine whether biapical stapling resection alone or resection of diseased, nonapical areas of emphysematous lung provides comparable physiologic outcomes or alters morbidity and mortality after lung volume reduction surgery (LVRS). DESIGN: Consecutive case-series analysis. SETTING: Urban university hospital. PATIENTS: Forty-seven patients ([mean +/- SD] aged 58+/-8 years; 18 men) with severe emphysema (FEV1, 0.7+/-0.2 L; total lung capacity [TLC], 139+/-23% predicted). INTERVENTIONS: Thirty-two patients underwent biapical LVRS, 27 by median sternotomy (MS) and 5 by video-assisted thoracoscopic surgery (VATS), and 15 underwent nonapical resection, 9 by MS and 6 by VATS. Patients were assessed for postoperative complications (respiratory tract infections, air leak duration, and death), length of stay, and physiologic parameters, which included a 6-min walk distance, spirometry, lung volume, gas exchange, diaphragm strength, and quality-of-life measures. MEASUREMENTS AND RESULTS: Patients were studied at baseline and at 3 months postoperatively. At the preoperative baseline, both groups had similar ages (57 vs 60 years; p = 0.2), 6-min walk distance (294 vs 263 m; p = 0.3), FEV1 (28% vs 29% predicted; p = 0.6), degree of hyperinflation (TLC, 138% vs 141% predicted; p = 0.8), gas exchange (PaO2/fraction of inspired oxygen, 344 vs 313, p = 0.1; PaCO2 46 vs 48 mm Hg, p = 0.4), and diaphragm strength (maximal transdiaphragmatic pressure sniff, 54 vs 46 cm H2O, p = 0.4). Resected tissue weight was similar in both groups (94 vs 93 g, p = 0.9). There were no differences in the mean percentage of change from baseline for these physiologic parameters or for quality-of-life measures between the two groups. The 6-min walk distances increased by 20% and 33%, FEV1 increased by 37% and 38%, the degrees of hyperinflation (residual volume/TLC) decreased by 16% and 15%, and the quality-of-life scores improved by 51% and 41%, respectively, in the groups that underwent biapical and nonapical resections at 3 months post-LVRS. The length of stay in the hospital for LVRS (18 vs 23 days; p = 0.4) and the duration of air leak (10 vs 15 days; p = 0.4) were also similar. Complications between the two groups (biapical vs nonapical) were similar (respiratory tract infection, 47% vs 60%, p = 0.2; reintubation, 34% vs 33%, p = 0.2; reoperation, 9% vs 20%, p = 0.4; and death, 9% vs 7%, p = 0.2). CONCLUSIONS: LVRS, by biapical or nonapical resection, produces similar improvements in lung function, exercise, diaphragm strength, and quality of life, with comparable morbidity and mortality.

Treatment of left pneumonectomy syndrome with an expandable endobronchial prosthesis.

Postneumonectomy syndrome has only been described after a right pneumonectomy except in cases of congenital mediastinal anomalies or right-sided aortic arch. Placement of Silastic prostheses into the empty hemithorax is the preferred surgical treatment; however, other nonsurgical options exist. Herein, we report a case of left postpneumonectomy syndrome in an adult who was successfully treated with the placement of an endobronchial stent.

Coital behavior of male Pteropus scapulatus (little red flying foxes) in captivity.

Copulation in Pteropus scapulatus, the little red flying fox (suborder Megachiroptera), is characterised by brief orogenital grooming for 20 s; a single mount lasting 175 s; a single intromission, which includes a mean of 20 s thrusting in most copulations; ejaculation, lasting only about 9 s, observed in about 20% of copulations; and lock et copula, for about 155 s. In 65% of copulations, mating between the same pair resumes, usually after about 35 s. Each pair typically undertakes a series of two-three copulations at a time. Copulation is the dorso-ventral position, while both animals hang by their feet in their normal head-down posture. An unusual feature of their coitus is that each animal supports its own weight, and the female appears undisturbed by the male's thrusting movements. Mating is essentially silent and still. Peak mating occurs in November and December (late spring/early summer), with fertile matings being rare at other times.

"Inappropriate" emergency department use: a comparison of three methodologies for identification.

OBJECTIVE: To determine the level of agreement between the rates of "inappropriate" ED visits assigned to a cohort of ambulatory patients based on three methods of defining ED use appropriateness. METHODS: Ambulatory adult patients seen at one urban, university-based teaching hospital ED between 8 AM and midnight during select days from April to June 1994 were assessed regarding the appropriateness of their ED visits. Patients triaged to acute resuscitation rooms in the ED were excluded. Eligible patients were asked to complete a 90-question survey including demographics and health service use (response rate 81%). The appropriateness of ED use was assessed for consenting respondents by 1) application of a list of 51 non-emergent complaints that have been used by managed care providers and previously published (TRIAGE), 2) use of ten explicit criteria (e.g., need for parenteral medication) from prior publications (EXPLICIT), and 3) the consensus of two emergency physicians (EPs) reviewing the records of ED patients (PHYS). All three methods were applied at the time of retrospective chart review. The agreement between methods was evaluated using kappa scores. RESULTS: Of the 892 eligible respondents, 64% were white, 54% were employed, 50% were female, and 29% were uninsured. Of the respondents, 26% had no regular source of ambulatory care and 25% considered the ED their regular source of care. The assigned rates of "inappropriate" visits using the three definitions were TRIAGE, 58%; PHYS, 47%; and EXPLICIT, 42%. Of those deemed "inappropriate" by the EXPLICIT criteria, 81% also were judged as "inappropriate" by the TRIAGE criteria, and 72%, by the PHYS criteria. Of those patients deemed "inappropriate" by the TRIAGE criteria, 59% also were judged as "inappropriate" by the EXPLICIT criteria, and 66%, by the PHYS criteria. Levels of agreement (kappas) were TRIAGE/EXPLICIT, 0.39; TRIAGE/PHYS, 0.42; and EXPLICIT/PHYS, 0.42. CONCLUSION: There is only moderate agreement between different methods of determining appropriateness of ED use. Until further refinement is made in triage assessment, managed care organizations and EPs should remain cautious when implementing a protocol that defines and restricts "inappropriate" ED visits.

Enhanced emergency department referral improves primary care access.

OBJECTIVE: People who use the emergency department (ED) as their main source of medical care cite access barriers to primary care as the reason. The purpose of this study was to test an intervention designed to refer regular ED users to primary care. STUDY DESIGN: A prospective randomized clinical trial. PATIENTS AND METHODS: Adults who stated the ED is their regular source of care and have no primary care (n = 189) were randomized to 2 groups: the intervention being studied or usual care. The study took place over 3 months at a northeastern urban hospital. RESULTS: Subjects in the intervention group were more than twice as likely to keep the primary care appointment compared with the usual care group, and most also received some measure of preventive care. There was no significant difference in ED utilization by these patients in the 12-month period following study entry. CONCLUSION: Making an appointment with detailed instructions during a visit to the ED markedly improves show rates at follow-up appointments with a primary care provider and allowed for opportunity to provide important preventive services.

Chronic pulmonary disease in the trauma patient.

Despite a better understanding of the pathophysiologic changes that occur in the respiratory system as a result of trauma and surgery, pulmonary complications remain an important contributor of morbidity and mortality. Pre-existing pulmonary disease predisposes the patient to these complications and further complicates their management. Timely identification of chronic pulmonary dysfunction and the early institution of pharmacologic measures and respiratory care, as outlined, may reduce pulmonary complications in this high-risk group.

Seasonal reproduction in flying foxes, reviewed in the context of other tropical mammals.

Megachiroptera inhabit the Old World tropics and most are seasonal breeders having defined times of testis growth, mating and parturition. In Pteropus scapulatus, the little red flying fox, the robust rhythm of testis cycles is resistant to modification by photoperiod. P. poliocephalus, the greyheaded flying fox, can be manipulated by photoperiod but responds slowly and incompletely. Most mammals live in the tropics, many in seasonally harsh climates, and many breed seasonally. However, few long-lived tropical mammals have been investigated for photoperiodic entrainment of annual reproductive cycles, and only animals from the edge of the tropics have responded. Thus, in long-lived tropical mammals, factors that regulate seasonal breeding have not yet been identified. Endogenous oscillators may generate circannual rhythms centrally. Downstream pathways (reproduction, metabolism, antlers, etc.) may derive their rhythm directly from the oscillator or may be modified by environmental cues. Plasticity of the circannual oscillator resolves confusion from previous contrasts between circannual rhythms and environmentally cued patterns. Plasticity may continue throughout life (species responsive to zeitgebers), but the oscillator may be 'set' in utero in some tropical species. Feedback effects from temperature, nutrition, hormones, etc. can be readily tested in this model of an oscillator generating an endogenous circannual rhythm.

Pituitary content of luteinizing hormone reveals species differences in the reproductive synchrony between males and females in Australian flying-foxes (genus Pteropus).

Flying-foxes (genus suborder, Pteropus Megachiroptera) are long-lived tropical mammals. Their seasonal reproduction appears to be regulated by an endogenous, circannual rhythm modified by multiple environmental cues. Luteinizing hormone (LH) content in pituitary extracts was examined to establish the broad time-frame of pituitary stages in the reproductive seasonality of the flying-foxes. A comparison was made between the grey-headed flying-fox P. poliocephalus, which mates and conceives in autumn, and the little red flying-fox P. scapulatus, which mates and conceives in spring. In P. scapulatus, LH was maximum during the spring mating season at 1494 ng mg(-1) in males and 896 ng mg(-1) in females. In P. poliocephalus males, LH increased to 1082 ng mg(-1) in early summer, 4 months before the mating season; LH concentrations in male P. poliocephalus returned to a low of 222 ng mg(-1) by the time of the autumn mating, by which time the female P. poliocephalus expressed elevated LH concentrations (624 ng mg(-1)). Apparently in P. poliocephalus, the peak LH concentrations in females are delayed by 4 months relative to LH concentrations in males. This is associated with 4 months of energetic courtship on the part of male P. poliocephalus, which is not observed in P. scapulatus, the fertility of which is synchronized between the sexes. The heterologous radioimmunoassay developed using monoclonal antibody 518B7 confirmed classic suppression of LH during pregnancy and lactation in flying-foxes and LH elevation in response to gonadectomy. Juveniles generally had pituitary levels similar to non-breeding levels in adults.

Surgery for severe COPD. Lung volume reduction and lung transplantation.

A management strategy for patients with severe emphysema is shown in figure 2 on page 199. Although the reported physiologic improvements after LVRS are significantly less than those seen after lung transplantation, LVRS has the potential to improve functional performance in a larger number of patients because of wider availability. Moreover, it accomplishes these goals without the attendant risks associated with transplantation and immunosuppression. The efficacy of LVRS over standard medical therapy in influencing survival and favorably affecting physiologic variables at rest and during exercise remains to be elucidated in NETT. Lung transplantation should be reserved for those patients deemed unsuitable or too ill for LVRS. It is to be hoped that future developments in organ preservation techniques and immunosuppressive regimens will expand the donor pool and decrease the incidence of posttransplantation bronchiolitis.

Reproductive seasonality and the effect of the GnRH agonist deslorelin as a contraceptive in captive male Black Flying-foxes (Pteropus alecto).

Effective contraception would enhance genetic management of captive Pteropus species, which typically breed well in captivity. Male reproductive seasonality was monitored (15-mo interval) in captive P. alecto (6 controls and 5 treated with 4.7 mg deslorelin). In untreated males, there were seasonal changes in testicular volume, body weight and testosterone secretion; testicular volume and body weight peaked in February and March, respectively, whereas testosterone concentration remained >5 ng/ml before rising (P < 0.001) to 24.9 ± 3.6 ng/ml (mean ± SEM) in April. However, there was no corresponding change in sperm quality, and seminal vesicle gland (SVG) secretions remained present in ejaculates. In treated males, testosterone concentration had an initial 'flare' response (mean ± SEM peak: 19.95 ± 3.27 ng/ml) before declining (P < 0.001) by 32 d to basal levels, where it remained. In these males, there was reduced sperm motility after 1 mo (P < 0.001) and the absence of SVG secretions after 4 mo. However, aspermic ejaculates were first recorded 5 mo post-treatment. At 10 mo after treatment, spermatogenesis was still disrupted, when membrane-intact, but non-motile sperm were present in two individuals. Motile sperm were first recovered from one of these males 13 mo after deslorelin treatment. We concluded that captive P. alecto males: (a) had seasonal reproductive changes in testicular volume, body weight and testosterone secretion; (b) produced motile, membrane-intact sperm and SVG secretions throughout the year; and (c) had a rapid decline in testosterone concentration and consequent suppression of testicular function for at least 5 mo following deslorelin administration.

High activity antioxidant enzymes protect flying-fox haemoglobin against damage: an evolutionary adaptation for flight?

Flying-foxes are better able to defend haemoglobin against autoxidation than non-volant mammals such as sheep. When challenged with the common physiological oxidant, hydrogen peroxide, haemolysates of flying-fox red blood cells (RBC) were far less susceptible to methaemoglobin formation than sheep. Challenge with 1-acetyl-2-phenylhydrazine (APH) caused only half as much methaemoglobin formation in flying-fox as in ovine haemolysates. When intact cells were challenged with phenazine methosulfate (PMS), flying-fox RBC partially reversed the oxidant damage, and reduced methaemoglobin from 40 to 20% over 2 h incubation, while ovine methaemoglobin remained at 40%. This reflected flying-fox cells' capacity to replenish GSH fast enough that it did not deplete beyond 50%, while ovine RBC GSH was depleted to around 20%. The greater capacity of flying-foxes to defend haemoglobin against oxidant damage may be explained in part by antioxidant enzymes catalase, superoxide dismutase and cytochrome-b ( 5 ) reductase having two- to four-fold higher activity than in sheep (P < 0.001). Further, their capacity to limit GSH depletion to 50% and reduce methaemoglobin (in the presence of glucose), despite ongoing exposure to PMS may result from having ten-fold higher activity of G6PD and 6PGD than sheep (P < 0.001), indicating the presence of a very efficient pentose phosphate pathway in flying-foxes.

Comparative morphology of the pituitary gland in Australian flying foxes (Megachiroptera: genus Pteropus).

BACKGROUND: Investigations of reproductive endocrinology of flying foxes (genus Pteropus) have been hampered by inadequate information on the normal morphology of the megachiropteran pituitary. METHODS: The novel technique of graphical three-dimensional (3-D) reconstruction, supported by more traditional anatomical techniques, have now been used to examine the shapes of, the interrelations between, the lobes of the pituitary of the little red flying fox, Pteropus scapulatus. Statistical analysis of data from three species tested whether there were changes in pituitary size with annual cycles in function, particularly with key stages of reproduction. RESULTS: In the three species of Australian flying foxes examined, the hypophyseal cleft is closed; the pars intermedia extends over the rostral, ventral, and lateral surfaces of the neural lobe. The pars distalis is broad rostrally and extends over two-thirds of the lateral and ventral pars intermedia. The hypophyseal recess is broad at the median eminence, then narrows and extends through the infundibulum to, but not into, the neural lobe. In adult animals the pituitary weight was 10.0 +/- 0.3 mg (mean +/- s.e.) in P. scapulatus, 14.7 +/- 0.5 mg in Pteropus poliocephalus (greyheaded flying foxes), and 18.7 +/- 1.5 mg in Pteropus alecto (black flying foxes). Pituitary weight was not significantly affected by reproductive stage. CONCLUSIONS: Thus histologically, the adenohypophysis and neurohypophysis are similar to those of other mammals. Comparative differences in pituitary size reflected differences in species body size rather than cyclical reproduction.

The development of an 191Os----191mIr generator using an osmium chelate parent complex--I. Trans-dioxobismalonatoosmate(VI).

A 191Os----191mIr generator has been developed that has higher 191mIr yield and lower 191Os breakthrough than previous designs. These improvements have been realized through the use of the osmium chelate complex trans-dioxobismalonatoosmate(VI) as the parent species on the generator. The new generator provides an initial 191mIr yield of 40%/mL and 191Os breakthrough of 2-3 X 10(-3)% when eluted with a solution of 0.05 M malonic acid/0.10 M sodium chloride at pH 4. Other advantages of the new design include faster clearance of the 191Os breakthrough products and simpler assembly.