A nationwide investigation of radiation therapy event reporting-and-learning systems: Can standards be improved?

INTRODUCTION

Variation exists between event reporting-and-learning systems utilised in radiation therapy. Due to the impact of errors associated with this field of medicine, evidence-based and rigorous systems are imperative. The implementation of such systems facilitates the reactive enhancement of patient safety following an event. The purpose of this study was to evaluate Irish event reporting-and-learning procedures against the current literature using a developed evidence-based process map, and to propose recommendations as to how the national standard could be improved.

METHODS

Radiation Therapy Service Managers of all Irish radiation therapy institutions (n = 12) were invited to participate in an anonymous online questionnaire. Included in the questionnaire was a reporting-and-learning process map developed from evidence-based literature, which was used to assess the institution's practice through the use of vignettes. Frequency analysis of closed-ended questions and thematic analysis of open-ended questions was performed to assess the data.

RESULTS

A 91.7% response rate was achieved. The following areas were found to have the most variation with the evidence-based process map: event classification, external reporting, and dissemination of lessons-learned to a wider audience. Recommendations to standardise practice were made.

CONCLUSION

Opportunities for improvement exist within event reporting-and-learning systems of Irish radiation therapy institutions and recommendations have been made on these. These findings can provide learning for other countries with similar reporting systems.

Assessment of block height for satisfactory spinal anaesthesia for caesarean section

We investigated block heights that anaesthetists considered adequate for caesarean section to proceed under spinal anaesthesia. During 3 months, 15 obstetric anaesthetists recorded block height to touch, pinprick or cold when spinal anaesthesia was considered satisfactory for caesarean section to proceed. Median (IQR [range]) block height for touch, pinprick, first cold and icy were: T10 (T7-T12 [T3-L1]); T5 (T4-T6 [C7-L1]); T5 (T4-T6 [C7-L1]); and T3 (T2-T4 [C7-L1]), respectively. Modalities were significantly correlated for: touch and cold, p = 0.0001; touch and icy, p = 0.0007; touch and pinprick, p = 0.0018; cold and icy, p < 0.0001; cold and pinprick, p = 0.0001; icy and pinprick, p < 0.0001. Pairwise comparisons showed differences between all modalities (p < 0.001) apart from pinprick and first cold (p = 0.94). All women had satisfactory anaesthesia despite 76 (81%) having a block to touch below T6. Single modality assessment of block height, particularly using touch, may erroneously indicate inadequate anaesthesia for caesarean section.

A comparison of epidural and cerebrospinal fluid glucose in parturients at term: an observational study

BACKGROUND

Detecting inadvertent dural puncture during labour epidural insertion can be difficult when using a loss of resistance to saline technique. Testing fluid for glucose that leaks from a Tuohy needle may confirm the presence of cerebrospinal fluid and infer inadvertent dural puncture. This study compared the glucose content of intrathecal fluid obtained during spinal anaesthesia for elective caesarean delivery with that of fluid from a Tuohy needle or epidural catheter when establishing epidural analgesia for labour.

METHODS

Women aged ≥18 years undergoing elective caesarean delivery and labouring parturients who requested epidural analgesia were recruited prospectively in a tertiary referral centre over a three-month period. Fluid was collected into a sterile container either during spinal anaesthesia or from a labour epidural needle. Glucose content was evaluated using a bedside blood glucometer and laboratory colorimetric analyzer.

RESULTS

Of the 118 women approached, 115 participated. All 40 women having spinal anaesthesia and 2/75 (2.7%) women having epidural analgesia, in whom inadvertent dural puncture was subsequently confirmed, had fluid samples testing positive for glucose. Median [range] laboratory glucose readings were 2.9 [1.3-5.1] mmol/L for cerebrospinal fluid and <0.3 mmol/L in fluid that leaked from a Tuohy needle (P=0.0001).

CONCLUSION

When using a loss of resistance to saline technique for epidural catheter placement, bedside glucometer testing of fluid leaking from the epidural needle may be of value in the early detection of inadvertent dural puncture.

Effect of defoliation stress on 2-hydroxy cinnamic acid content at different growth stages in Melilotus albus

Melilotus albus (Medik.) is a pasture legume with potential value in Australian farming systems, especially in salt-affected areas. However, the use of this species has been limited because of concerns over high coumarin concentrations. The aim of this trial was to determine the effect of defoliation on the concentration of 2-hydroxy cinnamic acid, a coumarin precursor, at 3 stages of growth (vegetative, flowering and post-flowering) in 6 accessions. The concentration of 2-hydroxy cinnamic acid was determined by high performance liquid chromatography in leaves of plants grown in a glasshouse. Defoliation stress increased the 2-hydroxy cinnamic acid content in the leaves of all accessions studied by about 8%, from 0.89 to 0.96% of dry matter. The 2-hydroxy cinnamic acid concentrations were not significantly different between vegetative and flowering stages in any of the accessions studied, but showed a significant increase post-flowering for 4 out of the 6 accessions studied. This study indicates that grazing may increase the coumarin or 2-hydroxy cinnamic acid concentration in Melilotus albus, but in screening for suitable accessions to progress to new cultivars, it is not necessary to subject plants to a defoliation stress to rank the accessions for 2-hydroxy cinnamic acid or coumarin concentration.

Activated clotting time as a screening test prior to catheter-based cardiovascular procedures

The activated clotting time (ACT) was investigated as a rapid, inexpensive, point-of-service screening test for coagulation abnormalities prior to catheter-based procedures. A total of 963 patients were screened by obtaining a history, standard coagulation profile, and activated coagulation time. The prevalence of normal patients (normal ACT and coagulation profile) was 94% (sensitivity = 91%; specificity = 27%). A normal ACT had a positive predictive value of 95%. The ACT was an acceptable screening test due to its ability to predict positively a low rate of bleeding complication and normal coagulation studies. Patients with ACT > 150 sec should be further evaluated with a screening coagulation panel. Additionally, given its low specificity, coagulation studies should be obtained in high-risk patients since an abnormal ACT does not effectively correlate with abnormal coagulation studies.

Time-domain whole-field fluorescence lifetime imaging with optical sectioning

A whole-field time-domain fluorescence lifetime imaging (FLIM) microscope with the capability to perform optical sectioning is described. The excitation source is a mode-locked Ti:Sapphire laser that is regeneratively amplified and frequency doubled to 415 nm. Time-gated fluorescence intensity images at increasing delays after excitation are acquired using a gated microchannel plate image intensifier combined with an intensified CCD camera. By fitting a single or multiple exponential decay to each pixel in the field of view of the time-gated images, 2-D FLIM maps are obtained for each component of the fluorescence lifetime. This FLIM instrument was demonstrated to exhibit a temporal discrimination of better than 10 ps. It has been applied to chemically specific imaging, quantitative imaging of concentration ratios of mixed fluorophores and quantitative imaging of perturbations to fluorophore environment. Initially, standard fluorescent dyes were studied and then this FLIM microscope was applied to the imaging of biological tissue, successfully contrasting different tissues and different states of tissue using autofluorescence. To demonstrate the potential for real-world applications, the FLIM microscope has been configured using potentially compact, portable and low cost all-solid-state diode-pumped laser technology. Whole-field FLIM with optical sectioning (3D FLIM) has been realized using a structured illumination technique.

Application of the stretched exponential function to fluorescence lifetime imaging

Conventional analyses of fluorescence lifetime measurements resolve the fluorescence decay profile in terms of discrete exponential components with distinct lifetimes. In complex, heterogeneous biological samples such as tissue, multi-exponential decay functions can appear to provide a better fit to fluorescence decay data than the assumption of a mono-exponential decay, but the assumption of multiple discrete components is essentially arbitrary and is often erroneous. Moreover, interactions, both between fluorophores and with their environment, can result in complex fluorescence decay profiles that represent a continuous distribution of lifetimes. Such continuous distributions have been reported for tryptophan, which is one of the main fluorophores in tissue. This situation is better represented by the stretched-exponential function (StrEF). In this work, we have applied, for the first time to our knowledge, the StrEF to time-domain whole-field fluorescence lifetime imaging (FLIM), yielding both excellent tissue contrast and goodness of fit using data from rat tissue. We note that for many biological samples for which there is no a priori knowledge of multiple discrete exponential fluorescence decay profiles, the StrEF is likely to provide a truer representation of the underlying fluorescence dynamics. Furthermore, fitting to a StrEF significantly decreases the required processing time, compared with a multi-exponential component fit and typically provides improved contrast and signal/noise in the resulting FLIM images. In addition, the stretched-exponential decay model can provide a direct measure of the heterogeneity of the sample, and the resulting heterogeneity map can reveal subtle tissue differences that other models fail to show.

Uterine artery embolization for the treatment of adenomyosis: clinical response and evaluation with MR imaging

OBJECTIVE

This study was performed to evaluate the MR imaging appearance and clinical response of patients undergoing uterine artery embolization for the treatment of menorrhagia due to adenomyosis.

MATERIALS AND METHODS

A retrospective review of 15 patients with adenomyosis and menorrhagia who underwent uterine artery embolization was performed. The diagnosis of adenomyosis was based on established MR imaging criteria. Clinical response was assessed at a minimum of 3 months after embolization. Follow-up MR imaging was performed 6 months after embolization.

RESULTS

Of the 15 patients in this study, five had diffuse adenomyosis without evidence of uterine fibroids, one had focal adenomyosis without evidence of uterine fibroids, and the remaining nine had adenomyosis with one or more fibroids. At follow-up, 12 (92.3%) of the 13 patients reported significant improvement in presenting symptoms and quality of life. One patient continued experiencing menorrhagia, and one patient experienced amenorrhea during the 5 months of follow-up after embolization. MR imaging in nine patients, performed at a mean of 5.9 months after embolization, revealed significant reductions in median uterine volume (42%), median fibroid volume (71%), and mean-junctional-zone thickness (11 mm; 33%; p < 0.5). Six of the nine patients had subendometrial regions of decreased T2 signal intensity after embolization.

CONCLUSION

Uterine artery embolization is a promising nonsurgical alternative for patients with menorrhagia and adenomyosis. Significant improvement in presenting symptoms and in quality of life is associated with decreases in uterine size and junctional zone thickness. Larger prospective studies are needed to establish the safety and efficacy of this procedure for patients with adenomyosis.

The further development of rainbow trout primary epithelial cell cultures as a diagnostic tool in ecotoxicology risk assessment

The use of short-term cytotoxicity assays for the initial screening of chemicals not only aids in establishing priorities for the selection of chemicals that should be tested in vivo, but also decreases the time in which potential toxicants can be valued. Rainbow trout primary skin epithelial cell cultures are one such assay. Rainbow trout primary skin cell cultures contain two cell types, keratinocytes and goblet mucus cells. Two aquatic pollutants, copper and prochloraz were screened using this cell system. The influence of media composition on the effects of the aquatic pollutants was also studied by testing the chemicals in both serum-containing and serum-free medium and the morphological changes that occurred within the cell cultures recorded. The concentration of copper that causes a reduction of 90% in the residual of day 3 growth of the primary cell culture system was found to be approximately 10 fold more than that of prochloraz. Prochloraz was found to cause a greater reduction in growth area when added to the primary cell culture system in serum-free medium than in serum-containing medium. Copper, in contrast, was found to exert reduced toxicity when added to the test cultures in serum-free medium compared with addition in serum-containing medium. Prochloraz was found to kill the epithelial cells by a process of necrosis. Copper, was found to kill the epithelial cells by both necrosis and apoptosis in a ratio of 2:1. It was also observed that as the dose of both chemicals increased, the number of goblet cells contained in the cell cultures decreased. A PAS stain was carried out to determine if the goblet cells were exocytosing their contents onto the cell culture surface. It was found that as chemical exposure increased the number of cells expressing positivity for mucus also increased. The results of this study add further evidence to support that primary cell cultures are a very appropriate model for toxicity risk assessment.

Protein synthesis costs could account for the tissue-specific effects of sub-lethal copper on protein synthesis in rainbow trout (Oncorhynchus mykiss)

This study investigates protein synthesis, following exposure to sub-lethal Cu, in rainbow trout in vivo and in vitro. The investigation has two aims: to determine if perturbations in protein synthesis, compared with other physiological changes, are a biomarker of Cu pollution and to evaluate the most productive role of cellular models in ecotoxicology. Protein synthesis rates were measured by labelling with 3H-phenylalanine. In vivo this was applied by a single (i.p.) injection and in vitro by bathing the cells in 3H-phenylalanine labelled culture media. The effects in vivo were tissue specific. After 3 weeks' exposure to 0.7 microM Cu only skin protein synthesis was reduced. Gills and liver from the same fish were unaffected. This reduction in skin protein synthesis appears to be more sensitive than some other biomarkers reported in the literature. However, Cu concentrations greater by orders of magnitude were required to reproduce this reduction in protein synthesis in skin cell explants (200 and 400 microM). Hepatocyte protein synthesis was unaffected by 10, 20 and 40 microM Cu and a separate investigation has also shown that 25 and 75 microM Cu does not effect protein synthesis in cultured gill cells. Oxygen consumption rates were also measured in vitro by monitoring the decline in O2 partial pressure. The Cu concentrations given above resulted in a decline in O2 consumption rates in the respective cell types. By measuring protein synthesis and O2 consumption after treatment with a protein synthesis inhibitor (cycloheximide), the costs of protein synthesis were also determined. Synthesis costs in hepatocytes are close to the theoretical minimum and are only marginally affected by Cu. Gill cell synthesis costs are also minimal and are unaffected. In skin explants, the reduction in protein synthesis was accompanied by greatly increased synthesis costs. This in vitro result offers a hypothesis as to the tissue-specific effects in vivo; i.e. the energetic demand of protein synthesis may determine tissue sensitivity or susceptibility. Cell or tissue types with high protein synthesis rates are able to avoid detrimental increases in the synthesis cost when exposed to Cu. In tissues with a low protein synthesis rate any further reduction is more likely to incur a potentially damaging increase in protein synthesis costs. Thus, whilst in vitro models may have little practical use in environmental monitoring, they may be best used as a mechanistic tool in understanding susceptibility or tolerance to sub-lethal Cu.

Whole-field optically sectioned fluorescence lifetime imaging

We describe a novel three-dimensional fluorescence lifetime imaging microscope that exploits structured illumination to achieve whole-field sectioned fluorescence lifetime images with a spatial resolution of a few micrometers.

Outpatient uterine artery embolization for symptomatic uterine fibroids: experience in 49 patients

PURPOSE

To assess the feasibility of performing uterine artery embolization as an outpatient treatment for symptomatic uterine fibroids.

MATERIALS AND METHODS

Forty-nine consecutive patients (mean age, 44.5 years; range, 28-54 years) underwent uterine artery embolization during a 12-month period. Embolization was performed with 350-500 microm polyvinyl alcohol particles (44 of 49) or Gelfoam pledgets (five of 49). At discharge, patients were given instructions regarding the constitutional symptoms to expect after embolization. A specific medication regimen consisting of prochlorperazine, ketorolac, meperidine, and hydrocodone was prescribed for relief of these symptoms. All patients were telephoned within 24 hours of discharge. During long-term follow-up, a questionnaire was administered to all patients to evaluate the periprocedural experience. Three-month clinical follow-up was available in 26 patients and 6-month imaging follow-up was available in 16 patients.

RESULTS

Fourteen patients presented with menorrhagia, six had bulk-related symptoms (abdominal distension, stress incontinence, pelvic pain), and 29 had both. Technical success for bilateral embolization was 98%. Forty-seven of 49 patients were discharged to home 6-8 hours after the procedure; two patients required overnight observation in an ambulatory unit (one because of postprocedure hypertension and one because of a late procedure completion time). At the first follow-up phone call, reported symptoms included pelvic pain/cramping in 83.7% (41 of 49), fatigue in 75.5% (37 of 49), nausea/vomiting in 46.9% (23 of 49), and a nonpurulent vaginal discharge in 18.4% (nine of 49). These symptoms were satisfactorily controlled with discharge medications in 48 of 49 patients. No patients returned to the hospital or visited an emergency room during the first 48 hours after discharge. Forty-six of 49 patients were satisfied with the decision for home discharge. The average uterine volume reduction in 16 patients with 6-month imaging follow-up was 47.5%; 88.5%, of patients (23 of 26) with 3-month clinical follow-up reported improvement or elimination of symptoms.

CONCLUSION

With defined telephone follow-up, staff availability, and a protocol designed to alleviate the postprocedure constitutional symptoms, uterine artery embolization is both safe and effective when performed as an outpatient procedure.

Management of failing prosthetic bypass grafts with metallic stent placement

PURPOSE

To evaluate the role of metallic stents in treating stenoses involving prosthetic arterial bypass grafts.

METHODS

Patients undergoing stent placement within a failing prosthetic bypass graft, during a 41-month period, were reviewed for treatment outcome and complications. The indications for stent placement in 15 patients included severe claudication (n = 3), rest pain (n = 9), and minor or major tissue loss (n = 3). Lesions were at the proximal anastomosis (n = 6), the distal anastomosis (n = 3), or within the graft (n = 6).

RESULTS

Treatment with metallic stents was successful in all patients. There was one acute stent thrombosis, successfully treated with thrombolytic therapy. Follow-up data are available for a mean duration of 12.3 months. The mean duration of primary patency was 9.4 months with 6- and 12-month primary patency rates of 51.9% and 37.0%, respectively. The mean duration of secondary patency was 12.1 months with 6- and 12-month secondary patency rates of 80.0% and 72.7%, respectively. Two patients with discontinuous runoff and preexisting gangrene required a below-knee amputation. Six patients were revised surgically after stent placement (at a mean of 10.8 months). Three late deaths occurred during follow-up.

CONCLUSION

Given the mortality risks of surgical revision and the reduced life expectancy of this patient population, metallic stent placement represents a viable, short-term treatment option for stenoses within or at the anastomoses of prosthetic grafts. Further evaluation is warranted to compare intragraft stent placement with surgical graft revision.

Fluorescence lifetime imaging with picosecond resolution for biomedical applications

We describe a novel whole-field fluorescence lifetime imaging system, based on a time-gated image intensifier and a solid-state laser oscillator-amplifier, that images lifetime differences of less than 10 ps. This system was successfully applied to discrimination between biological tissue constituents.

Interaction of the fibrinolytic receptor, annexin II, with the endothelial cell surface. Essential role of endonexin repeat 2

Endothelial cells express a cell surface co-receptor for plasminogen and tissue plasminogen activator (t-PA) which we recently identified as annexin II (Hajjar, K. A., Jacovina, A. T., and Chacko, J. (1994) J. Biol. Chem. 269, 21191-21197). This protein enhances the catalytic efficiency of t-PA-dependent plasmin generation by 60-fold (Cesarman, G. M., Guevara, C. A., and Hajjar, K. A. (1994) J. Biol. Chem. 269, 21198-21203). Here, we demonstrate that annexin II is constitutively translocated to the endothelial cell surface within 16 h of biosynthesis, and that cell surface annexin II comprises 4.3 +/- 1.0% of the total cellular pool. Exogenous 125I-annexin II bound to EGTA-washed endothelial cells with high affinity (Kd 49 nM) and in a calcium-dependent (I50 = 3 microM), phospholipid-sensitive manner. Peptides KASMKGLGTDED and YDSMKGKGTRDK, mimicking the calcium-binding "endonexin" motif (KGXGT) of annexin II, blocked its interaction with endothelial cells. Recombinant annexin II, bearing the calcium-binding site substitution D161A of core repeat 2, failed to compete with binding of the wild type protein to the cell surface, while E246A and D321A mutants, corresponding to core repeats 3 and 4, behaved as effective competitors. These data suggest that translocated annexin II interacts with cell surface phospholipid via a high affinity calcium-dependent binding site that includes residues 118-122 (KGLGT) and the coordinating Asp161 of core repeat 2. Thus, calcium-regulated expression of annexin II on the endothelial cell surface may play a central role in control of plasmin-mediated processes.

Fish oil and oat bran in combination effectively lower plasma cholesterol in the rat

Male rats were fed a semi-purified diet containing oat bran or wheat bran with or without a marine fish oil to investigate the effects of such combinations on lipid metabolism. Oat bran alone and wheat bran plus fish oil gave lower plasma cholesterol concentrations than wheat bran alone while oat bran plus fish oil gave the lowest. Oat bran increased plasma triacylglycerols compared with wheat bran but oat bran plus fish oil gave concentrations similar to those seen with wheat bran plus fish oil. Oat bran gave higher hepatic cholesterol synthesis rates and a higher activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase compared to wheat bran. The addition of fish oil to either bran diet decreased cholesterol synthesis but HMG CoA reductase activity was not reduced. Oat bran increased hepatic acyl coenzyme A:cholesterol acyl transferase (ACAT) activity and increased the ratio of esterified to unesterified cholesterol in hepatic microsomal membranes compared with wheat bran. Fish oil decreased hepatic LDL receptor activity and increased HDL binding activity when added to the wheat bran diet but these effects were not seen with oat bran. Oat bran also had no effect on hepatic lipoprotein receptor activity compared with wheat bran. These results show that fish oil and oat bran have complementary cholesterol lowering effects in the rat.

Effects of solvent extraction on the hypocholesterolaemic action of oat bran in the rat

In adult male rats fed on a cholesterol-free synthetic diet, plasma cholesterol concentrations were lowest with oat bran, intermediate with cellulose and highest with wheat bran. Plasma triacylglycerols (TAG) were similar with wheat bran and cellulose but higher with oat bran. The concentrations and pools of caecal volatile fatty acids (VFA) were lowest with cellulose and equally higher with oat bran and wheat bran. Plasma VFA concentrations in the hepatic portal vein reflected those in caecal digesta and were unrelated to plasma cholesterol. Feeding oat bran after extraction with n-pentane gave plasma cholesterol concentrations similar to that found with wheat bran. Reconstitution of oat bran with extracted lipids did not restore the cholesterol-lowering effect. Addition of the extracted material to a wheat-bran diet had no effect on plasma cholesterol. Plasma TAG were higher with the oat bran and reconstituted-oat-bran diets than with wheat-bran or cellulose diets. However, extracted oat bran + safflower oil gave similar TAG concentrations to that with wheat bran. These extractions and additions did not change caecal bile acid or neutral sterol concentrations. Effects of these diets on plasma cholesterol were unrelated to their tocotrienol or tocopherol content. Addition of n-pentane to oat bran followed by evaporation of solvent gave plasma cholesterol concentrations that were significantly higher than untreated oat bran but lower than similarly treated wheat bran. It is concluded that oat bran affects cholesterol metabolism through a pentane-soluble component as well as non-starch polysaccharides. It appears that the activity of this lipid is not transferable by simple addition of the solvent extract to the whole diet.

The changing prevalence of cervical human papilloma virus infection

In order to determine the change in frequency of human papillomavirus infection (HPV) over a 10-year period, cervical smears from 1978 were retrieved, cytologically reviewed and compared with cervical smears taken in 1988. In this way, the slides were reviewed using the same diagnostic criteria. The prevalence of HPV infection in the population assessed at Flinders Medical Centre, rose from 0.58% to 5.6% over this period.

Should I accept or reject my assignment?

This article examines the implications of one's decision to accept or reject a nursing assignment and presents alternatives to achieving equitable nursing assignments.

Field measurement of plasma and erythrocyte cholinesterases

We have optimized Ellman-type plasma and erythrocyte cholinesterase assays for the field determination of pesticide exposure. The assays employ stable, premixed, inexpensive colorimetric reagents and a simplified kinetic measurement procedure using a novel battery-operable light-emitting-diode-source colorimeter (LEDSC). These methods were compared to a field tintometric method for cholinesterase currently in widespread use, using samples from organophosphate-intoxicated hospitalized patients. In comparison to the colorimetric method, the tintometric method was less precise and consistently underestimated the extent of pesticide exposure. Methods for the effective field determination of pesticide exposure using cholinesterase assays are critically evaluated with regard to their practical, biochemical, and medical relevance.

Management of nonfamilial adenomatous polyps and colon cancers

There is evidence that patients with adenocarcinoma of the colon and synchronous adenomatous polyps are at an increased risk for developing metachronous colon cancer. A retrospective study was made of all patients with colon cancer at our institution and the associated Veterans Administration Hospital between 1974 and 1983 to help assess the need for more extensive colon resection in patients with colon cancer and synchronous adenomatous polyps. At our hospitals 470 new cases of colon cancer were identified. Nine percent (44/470) had colon cancer and concurrent adenomatous polyps. Seven (16%) of these 44 patients developed metachronous colon cancer, as compared with four of 426 patients without polyps at the initial surgery (p less than 0.001). Four patients without polyps at the initial surgery developed polyps at a later date; three of the four patients developed metachronous colon cancer. We believe that more extensive colon resection, such as total colectomy and ileoproctostomy, may play a role in preventing the occurrence of metachronous colon cancer in patients with colon cancer and synchronous adenomatous polyps. In addition, if adenomatous polyps develop after colon surgery, close endoscopic follow-up is required.

Direct metabolic effects of isoproterenol and propranolol in ischemic myocardium of the dog

The effect of either isoproterenol or propranolol on the metabolism of ischemic myocardium was examined. To ensure that all changes were due to changes in metabolism and not drug-induced changes in residual flow to the ischemic regions, we devised a preparation in which two coronary branches on the same heart were simultaneously perfused at a low flow rate. Microsphere measurements verified that the two ischemic regions were receiving identical blood flow rates. One branch received an infusion of 0.9% NaCl and the other received the drug. After 1 h both regions were biopsied and the high-energy phosphate levels in each region were determined. ATP and phosphocreatine each fell to about 50% of their starting values in the 0.9% NaCl-treated regions, and isoproterenol did not further depress the high-energy phosphate concentrations. Propranolol, on the other hand, significantly preserved the high-energy phosphate concentrations. We conclude that although isoproterenol seemed incapable of accelerating energy utilization in ischemic myocardium, propranolol is apparently capable of reducing it.

The failure of hydrogen peroxide to improve function in ischemically depressed myocardium

The hypothesis that hydrogen peroxide might lend inotropic support to ischemically depressed myocardium was critically tested in a canine model. A coronary branch was perfused at reduced flow to depress mechanical function. Since hydrogen peroxide infusion into the perfusate failed to alter the segment's contractile force, it was concluded that the previously described beneficial effects of hydrogen peroxide infusions are probably not related to a restoration of contractility in ischemic myocardium.

Smooth-pursuit eye movements in the newborn infant

The capacity of newborn infants to smooth-pursuit eye movements in single-target tracking and in optokinetic nystagmus to a moving striped field was examined utilizing DC electrooculography. Smooth-pursuit movements were observed in all infants who were alert during testing, but they occupied less than 15% of viewing time during single-target tracking. The velocity of smooth-pursuit segments in single-target tracking increased linearly to a target velocity of 19 degrees/sec and deteriorated rapidly at faster speeds. No smooth pursuit occurred above 32 degrees/sec in single-target tracking. By contrast, optokinetic nystagmus was observed at all field velocities to 40 degrees/sec, but the speed of the mean slow component increased linearly to 25 degrees/sec and diminished above that field velocity. Infant optokinetic nystagmus differed strikingly from that of adults in that tonic ocular deviation was in the direction of field movement rather than away from it. This feature of neonatal optokinetic nystagmus is consistent with deficient foveal function and suggests that the relatively poor smooth-pursuit performance of newborns may be related to foveal immaturity.