A265 TEMPORAL DYNAMICS OF SYMPTOMS AND GUT MICROBIOTA IN EPISODES OF IRRITABLE BOWEL SYNDROME

Background

Irritable bowel syndrome (IBS) is a disorder of gut-brain axis that manifests with chronic abdominal pain, altered bowel habits, and frequent psychiatric comorbidities. Despite mounting evidence showing gut microbiota composition and associated metabolites being altered in IBS, the mechanisms by which they drive the symptoms are unclear. We have previously shown that several IBS symptoms co-occur, that their severity vary among IBS subtypes (10.1093/jcag/gwab049.050), and that several bacterial taxa are differentially modulated during periods of symptom flares and remission. Here we investigate whether the changes in gut microbiome and bacterial metabolites are linked to symptom occurrence and severity.

Purpose

To investigate temporal associations of IBS symptoms with gut microbiota profiles and metabolites.

Method

16S rRNA gene sequencing was performed on stool samples of 28 IBS patients (IBS-D n=20, IBS-C n=8) and 10 healthy controls (HC), collected weekly over a period of 25 weeks, during which gut and mood symptoms were recorded (total of 950 samples). Correlations between principal ordinates obtained from symptom scores and microbiota beta diversity were studied using Procrustes analysis in R. Metabolomics was performed by Mass Spectrometry and analysed using MetaboAnalyst 5.0. Statistical significance was set at p<0.05.

Result(s)

Significant correlation was found between the symptom scores and microbiota beta diversity ordinates over time in 7 patients (5 IBS-D and 2 IBS-C subjects) out of 28 IBS patients. Metabolomics performed on samples selected based on Procrustes analysis and symptom severity scores of individual subjects showed that several pathways are altered in IBS patients (both subtypes) compared to HC, including primary bile acid biosynthesis, beta alanine metabolism, pyrimidine and histidine metabolism. Furthermore, during symptom flares, ornithine, citrulline and gluconic acid vary in IBS-D, while amino acids cysteine, methionine, threonine, and glycine vary in IBS-C subjects.

Conclusion(s)

Our results suggest that IBS symptoms and changes in gut microbiota composition and metabolites must be studied in conjunction, in order to understand the mechanisms underlying IBS pathophysiology. We found that same pathways are altered in IBS subjects irrespective of their subtype, suggestive of a basal metabolic shift in IBS patients. This shift may make them sensitive to further gut microbial modulation of carbohydrate and protein metabolism in IBS-D and IBS-C subjects, respectively, leading to symptom flares. Further analyses are needed to investigate these metabolites and associated bacteria, as they can help identifying subsets of patients with specific disease mechanisms. This will be a steppingstone in moving away from symptom-based subtyping towards mechanism-based grouping and developing effective treatment strategies accordingly.

Disclosure of Interest

None Declared

80 A PILOT POPS SERVICE (PERI-OPERATIVE CARE OF THE OLDER PERSON UNDERGOING SURGERY): A PROMISING START

Background

It is understood that older persons undergoing surgery benefit from Comprehensive Geriatric Assessment (CGA), however these services remain limited in Ireland. Latest guidelines recommend all patients over 65 undergoing surgery should be screened for frailty and receive a CGA if frailty is identified. Our pilot service was to implement this on our acute surgical in-patient ward.

Methods

Baseline data was gathered prior to implementation of our service. Interventions included education, dedicated sessions for geriatrician input on ward, single point of referral and increased signage. Patients identified as living with frailty (Rockwood Clinical Frailty Score (CFS) ≥5) then received CGA. Progress monitored with monthly audit and foundation doctor feedback surveys over a 6-month period.

Results

We have increased the percentage of patients over 65 being screened for frailty from 0% to a peak of 100% over our pilot 6-month period. Foundation doctor surveys showed an improvement in confidence in screening for frailty (19 to 100%) and managing frailty (13 to 80%). They also reported feeling more supported managing these patients (38% to 100%). Focusing on patients with CFS ≥5, we have shown a reduction in length of stay from a mean of 20 days to 11 days, albeit numbers remain small.

Conclusion

By increasing identification of frailty in older patients, we have managed to apply CGA to appropriate patients. Geriatrician input on the surgical ward has also allowed foundation doctors to feel supported and improve confidence in managing patients living with frailty. Furthermore, we have shown a trend towards reduced length of stay. However, our patient numbers remain low and there is a reliance on our team to screen all patients over 65. Our focus moving forward is for the surgical team to screen for frailty allowing us to expand the service to other surgical wards.

464 ESCALATION DURING COVID-19

Introduction

During the first surge of COVID-19 it was well recognised that early identification of a plan for escalation in the event of deterioration for each patient was vital. If no decision is documented it results in junior staff frequently making decisions regarding escalation in the out of hours period. This leads to patients, or family members, having these conversations with a doctor they may never have met before. My aim was to improve the documentation of escalation plans in all patients within the first 24 hrs of admission.

Method

Baseline data was collected in September 2019 with further samples in April 2020 and August 2020. Patient medical notes were reviewed to identify if an escalation plan had been made during the period from admission to post take ward round. A COVID admission pathway document was introduced with a specific section on Clinical Frailty Score and Escalation plan between the baseline and April 2020 data.

Results

Baseline data showed that only 12.8% of medical patients had a documented escalation plan within the first 24 hrs of admission to hospital. During the first surge in April 2020 this number had improved to 47% following introduction of the COVID-19 admission pathway. This included 100% of patients admitted to respiratory wards. Unfortunately when reassessed in August 2020, this number had fallen to 16%.

Conclusion

Introduction of clinical frailty scoring and an area specifically to document escalation discussions resulted in a marked improvement. Heightened awareness of rapid deterioration of patients during the first surge almost certainly played a role in this. Unfortunately this was not sustained once staff discontinued the use of COVID-19 admission document. Moving forward we will incorporate these sections into the medical and surgical admissions pathways in the hope it produces similar results.

Tuberculosis and diabetes in low and moderate tuberculosis incidence countries

In countries with low and moderate incidence of tuberculosis (TB), the disease tends to concentrate in specific high-risk populations such as people with diabetes mellitus (DM). We review the updated evidence on the association between 1) DM and active TB, and 2) DM and latent tuberculous infection (LTBI), and 3) we summarize the findings on the population-level impact of DM on TB epidemiology, with particular focus on low- and moderate-incidence settings. We conducted an updated review of studies on DM and active TB, and found 11 more cohort studies published after the previous systematic review from 2008. The updated pooled relative risk (RR) (2.03, 95%CI 1.62-2.55) of all the studies was substantially lower than the three-fold risk increase in the previous review. Substantial heterogeneity of RR across studies was found. Possible reasons for such heterogeneity include different levels of residual confounding, the effect of modification by age, and different levels of glycemic control in the population. In a recently published systematic review on DM and LTBI, one cohort study and 12 cross-sectional studies were identified. The results from cross-sectional studies suggest a significant but modestly increased risk of LTBI among patients with DM (pooled odds ratio 1.18, 95%CI 1.06-1.30). We reviewed evidence on the population-level impact of DM on TB epidemiology in studies using population-attributable fraction analysis and infectious disease modelling. Those studies revealed that DM accounted for a substantial TB burden in low- and moderate-incidence countries. Finally, we discussed the complex association of obesity, DM and TB risk and the impact of the global obesity pandemic on TB epidemiology.

Evaluation of Soluble CD30 as an Immunologic Marker in Heart Transplant Recipients

CD30 is an immunologic molecule that belongs to the TNF-R superfamily. CD30 serves as a T-cell signal transducing molecule that is expressed by a subset of activated T lymphocytes, CD45RO+ memory T cells. Augmentation of soluble CD30 during kidney transplant rejection has been reported. Our study sought to determine whether the level of sCD30 prior to heart transplant could categorize patients into high versus low immunologic risk for a poor outcome. A significant correlation was observed between high levels of soluble CD30 and a reduced incidence of infection. None of the 35 patients with high pretransplant levels of sCD30 level (>90 U/mL) developed infections posttransplantation. However, 9 of 65 patients who had low levels of sCD30 (<90 U/mL) developed infections posttransplantation (P < .02). No remarkable differences were noted among the other clinical parameters. The results also showed that the high-definition flow-bead (HDB) assay detected both weak and strong class I and class II HLA antibodies, some of which (weak class II HLA Abs) were undetectable by the anti-human globulin cytotoxicity method. In addition, more antibody specificities were detected by HDB. In conclusion, we have observed that high levels of sCD30 prior to heart transplant may be associated with greater immunologic ability and therefore produce a protective effect on the development of infection post heart transplant. We have also shown that the HDB assay is superior to the visual cytotoxicity method to detect HLA antibodies, especially those to class II HLA antigens.

Degenerative spondylolysis: a concise report of scintigraphic observations

OBJECTIVES

Spondylolysis is traditionally thought to be a diagnosis of adolescence and childhood, and is ascribed to mechanical stress through the immature pars interarticularis. Over the last 4 yr we have noted a presentation of spondylolysis in association with hypertrophic zygapophyseal joint disease in the lumbar spine in an older age group.

METHODS

Records of 94 patients presenting with low back pain were examined. A pattern of intense zygapophyseal joint uptake in association with extended uptake in the pars interarticularis was ascribed as degenerative spondylolysis.

RESULTS

The ages of the 94 cases ranged from 33 to 80 yr (mean 64 yr). There were 53 males and 41 females. In the group with degenerative spondylolysis the mean age was 72 yr, with four females and two males. None of these six patients gave a history of childhood spinal disease or back pain and all were relatively inactive in terms of current participation in sport. All cases of spondylolysis were confirmed by computed tomography scanning.

CONCLUSION

The finding of hypertrophic zygapophyseal joint disease in association with spondylolysis is easily recognized by scintigraphic tomographic imaging.

Empathy in medical students as related to academic performance, clinical competence and gender

CONTEXT

Empathy is a major component of a satisfactory doctor-patient relationship and the cultivation of empathy is a learning objective proposed by the Association of American Medical Colleges (AAMC) for all American medical schools. Therefore, it is important to address the measurement of empathy, its development and its correlates in medical schools.

OBJECTIVES

We designed this study to test two hypotheses: firstly, that medical students with higher empathy scores would obtain higher ratings of clinical competence in core clinical clerkships; and secondly, that women would obtain higher empathy scores than men.

MATERIALS AND SUBJECTS

A 20-item empathy scale developed by the authors (Jefferson Scale of Physician Empathy) was completed by 371 third-year medical students (198 men, 173 women).

METHODS

Associations between empathy scores and ratings of clinical competence in six core clerkships, gender, and performance on objective examinations were studied by using t-test, analysis of variance, chi-square and correlation coefficients.

RESULTS

Both research hypotheses were confirmed. Empathy scores were associated with ratings of clinical competence and gender, but not with performance in objective examinations such as the Medical College Admission Test (MCAT), and Steps 1 and 2 of the US Medical Licensing Examinations (USMLE).

CONCLUSIONS

Empathy scores are associated with ratings of clinical competence and gender. The operational measure of empathy used in this study provides opportunities to further examine educational and clinical correlates of empathy, as well as stability and changes in empathy at different stages of undergraduate and graduate medical education.

Impact of health care system on physicians' discontent

This study was designed to investigate the impact of physicians' perceptions of the health care system on their discontent with their profession. By using a random digit dialing technique, a structured telephone interview was conducted with 401 generalist physicians (343 men, 56 women) who were practicing medicine at least for five years and were younger than 65 years. Physicians' willingness to choose medicine again was correlated with their perceptions of different aspects of the health care system. Of the total participants, 288 (72 percent) indicated that they would choose medicine again, 91 (23 percent) would not choose medicine, and 22 (5 percent) were not sure. Results of the step-wise logistic regression showed that after adjustment for physicians' gender and age, those who would not choose medicine again were more than twice as likely as other physicians who would choose medicine to believe that the health care environment will deteriorate more in the future (odds ratio = 2.1, p < .01), were less than half as likely to believe that physicians nowadays share more responsibilities with other health care professionals (odds ratio = .42, p < .01), and were less than half as likely to confirm that patients understand their health insurance better than before (odds ratio = .46, p < .01). Findings suggest that physicians' discontent can be predicted by their negative perceptions of the health care environment. Findings have implications for improving the quality of professional and personal life of the physician, thus improving the quality of care and satisfaction of the patient.

Left mini-thoracotomy for beating heart bypass grafting: a safe alternative to high-risk intervention for selected grafting of the circumflex artery distribution

BACKGROUND

Progression of disease and bypass graft attrition results in a population of patients who require repeated coronary interventions. Frequently, these patients have patent internal mammary artery grafts and require isolated intervention to the circumflex distribution. As an alternative to high-risk repeated sternotomy and conventional bypass surgery or catheter-based intervention, the circumflex marginal vessels may be approached by thoracotomy. We reviewed our experience in revascularizing the circumflex distribution with off-pump techniques via left mini-thoracotomy.

METHODS AND RESULTS

Thirty-two patients underwent off-pump bypass grafting of the circumflex vessels via thoracotomy from December 1995 to April 2000. Twenty-seven patients presented with circumflex disease after having previous bypass grafting. Five patients, who presented with circumflex disease and either nondiseased or ungraftable disease in their other arteries, were revascularized as a primary procedure. There was no observed mortality. Seven patients (22%) required inotropes on leaving the operating room, and 3 patients (9.4%) received transfusion of packed red blood cells. There was 1 reoperation for bleeding and 1 patient with a postoperative neurological deficit. There were no perioperative myocardial infarctions. The average length of stay was 4.8 days from time of surgery to discharge.

CONCLUSIONS

Off-pump grafting via thoracotomy provides a safe and effective alternative approach for patients requiring limited revascularization. Potential cardiac injury and danger to viable grafts from repeated sternotomy is minimized, and manipulation of the diseased ascending aorta is avoided. Morbidity, hospital length of stay, and cost are less than for conventional repeated coronary bypass surgery.

A study of U.S. orchards to identify potential sources of Escherichia coli O157:H7

The association of unpasteurized apple cider with Escherichia coli O157:H7 foodborne illness has led to increased interest in potential reservoirs of this pathogen in the orchard. Fourteen U.S. orchards were surveyed in autumn 1999 to determine the incidence and prevalence of E. coli O157:H7, E. coli, total aerobic microflora, and yeasts and molds. Fruit samples (n = 63) (eight apple and two pear varieties) and soil, water, and fecal samples were collected. Samples were plated on (i) tryptic soy agar for total mesophilic aerobic count, (ii) E. coli and coliform Petrifilm for total coliforms and E. coli, and (iii) yeast and mold Petrifilm. Samples positive for coliforms and E. coli were enriched and tested for E. coli O157:H7. Fruit was also tested for internalization of microflora by aseptically removing the core, stem, and calyx areas, and the individual sections were assessed for the categories of microflora listed above. E. coli was detected in soil and water and in 6% of fruit samples (three pear samples and one apple sample), generally collected from areas previously designated as high risk in this study. However, no E. coli O157:H7 was found. Coliforms were found in 74% of fruit samples and were internalized in the cores of 40% of fruit tested. Yeasts and molds were internalized in 96.7% of samples and aerobic bacteria in 89.6%. E. coli was not found to be internalized. Total aerobic counts and total coliforms were higher in dropped and damaged fruit (P < 0.05). Findings suggest that dropped or damaged fruit should not be included in fruit designated for the production of unpasteurized juice or for the fresh or fresh-cut market. In addition, orchards should be located away from potential sources of contamination, such as pastures.

Clinical significance of the arthroscopic drive-through sign in shoulder surgery

PURPOSE

During arthroscopy of the shoulder, the ability to pass the arthroscope easily between the humeral head and the glenoid at the level of the anterior band of the inferior glenohumeral ligament is considered a positive drive-through sign. The drive-through sign has been considered diagnostic of shoulder instability and has been associated with shoulder laxity and with SLAP lesions. The goal of this study was to examine the prevalence of the drive-through sign in patients undergoing shoulder arthroscopy and to determine its relationship to shoulder instability, shoulder laxity, and to SLAP lesions.

TYPE OF STUDY

Case series.

METHODS

We prospectively studied 339 patients undergoing arthroscopy of the shoulder for a variety of diagnosis from 1992 to 1998. The drive-through sign was performed with the patients in a lateral decubitus position and under general anesthesia. The drive-through sign was correlated with preoperative physical findings, intraoperative laxity testing, and with intra-articular pathology at the time of arthroscopy.

RESULTS

The arthroscopic evaluation showed that drive-through sign was positive in 234 (69%) shoulders. For the diagnosis of instability, the drive-through sign had a sensitivity of 92%, a specificity of 37. 6%, a positive predictive value of 29.9%, a negative predictive value of 94.2%, and an overall accuracy of 49%. There was an association between the drive-through sign and increasing shoulder laxity, but not with SLAP lesions.

CONCLUSIONS

This study shows that a positive drive-through sign is not specific for shoulder instability but is associated with shoulder laxity. This arthroscopic sign should be incorporated with other factors when considering the diagnosis of instability.

A comparison of the personality profiles of internal medicine residents, physician role models, and the general population

PURPOSE

To compare personality profiles of internal medicine residents with those of the general population and positive role models in medicine.

METHOD

A widely used personality inventory, NEO PI-R, which measures five major personality factors and 30 important personality facets, was administered in 1998 to 104 physicians in internal medicine residency and earlier to a nationwide sample of 188 physicians selected as positive role models in medicine.

RESULTS

The internal medicine residents, compared with the general population, were more likely to be attentive, to have deeper intellectual curiosity, to have higher aspiration levels, to have more vivid imaginations, to be more receptive to their emotions, to be interested in mental stimulation, and to think carefully before acting. The residents, compared with role models in medicine, were less eager to face challenges, less able to control their impulses, less able to cope with adversity, less easygoing, and less relaxed, but were more likely to crave excitement.

CONCLUSION

Internal medicine residents and positive role models in medicine have some distinct personal qualities. Understanding the qualities of successful physicians can be helpful in career counseling of medical students and young physicians.

Single-photon emission tomography of a computerised model of pulmonary embolism

Planar pulmonary scintigraphy is currently the standard investigation for the diagnosis of pulmonary embolism. There are a number of problems with the technique, particularly in patients with an intermediate scan report under the PIOPED criteria. The technique is also under threat from the increasing use of spiral CT angiography. A putative improvement may be gained by use of tomography. The incremental value of tomography over planar studies was therefore evaluated in a virtual model of pulmonary scintigraphy. A model of the segmental anatomy of the lungs was developed from computed tomography, cadaveric human lungs and available anatomical texts. Counts were generated within the phantom by Monte Carlo simulation of photon emission. Eighteen single segmental lesions were interspersed with 47 subsegmental defects and displayed on an Icon reporting station. These were presented in the transaxial, sagittal and coronal planes to four experienced reporters to obtain assessment of defect size. Planar studies of the same defects were displayed to the same observers in the standard eight views with a normal study for comparison. With planar studies, the accuracy of estimation of defect size was 51% compared with 97% using tomographic studies. Defects in the medial basal segment of the right lower lobe were not identified in planar studies but were easily seen by all observers in the tomographic study. It is concluded that there is marked improvement in the accuracy of determination of defect size for tomographic studies over the planar equivalents. This is especially important in the lung bases, the most common reported site of pulmonary emboli. Tomography permits visualisation of defects in the medial basal segment of the right lung, which are not seen in planar studies.

Oral use of interferon-alpha stimulates ISG-15 transcription and production by human buccal epithelial cells

ISG-15 is a 15-kDa protein encoded by an interferon (IFN)-stimulated gene (ISG), which is transcriptionally regulated by IFN-alpha and IFN-beta. Considered as part of the cytokine network, ISG-15 has the potential to amplify the immunomodulatory effects of these IFNs by enhancing IFN-gamma production, natural killer cell proliferation, and lymphokine-alphactivated killer cell cytotoxicity. To understand better the mechanism(s) of action of orally administered IFN-alpha, we have studied the effect of IFN-alpha on ISG-15 gene expression by human buccal epithelial cells (BEC). For in vitro studies, ISG-15 mRNA and protein levels were measured in BEC incubated for 0.5, 2, and 9 h with 100 or 1,000 IU/ml of human lymphoblastoid IFN-alpha. For in vivo studies, ISG-15 mRNA was measured in BEC samples collected at baseline, and 0.5, 2, and 9 h after 5-20 min of oral rinsing with 10 ml of IFN-alpha (1,000 IU/ml). ISG-15 mRNA was measured by reverse transcriptase polymerase chain reaction (RT-PCR), and ISG-15 protein production by Western Blot analysis. IFN-alpha augmented BEC ISG-15 gene expression in a concentration dependent manner both in vivo and in vitro. We conclude that orally administered IFN-alpha exerts its immunomodulatory effects in humans in part by upregulating the production of ISG-15 by BEC, thereby enhancing the immune reactivity of mucosa-associated lymphocytes.

Phase I-II evaluation of rapid sequence tandem high-dose melphalan with peripheral blood stem cell support in patients with multiple myeloma

This study was designed to determine the maximum tolerated dose (MTD) of high-dose melphalan (HDM), with peripheral blood stem cell support, that could be given twice within 90 days to patients with multiple myeloma. Twenty patients received tandem HDM at 160, 180 or 200 mg/m2 and a total of 55 were treated at the estimated MTD of 200 mg/m2. Seventeen of 55 (31%) did not receive cycle 2; six because of low CD34+ cell yields, three because of severe (n = 1) or fatal toxicities (n = 2) and eight for other reasons. The median interval between doses for 38 patients was 70 days (range 41-225). Three of 55 patients (5%) died of treatment-related causes. In patients completing two cycles of HDM, at any dose level, the complete remission rate improved from 15% following cycle 1 to 55% following cycle 2. The probabilities of survival, event-free survival and relapse or progression at 18 months for the 55 patients treated at the MTD were 0.84, 0.76 and 0.20, respectively, with a median follow-up of 19 months (range 9-36) from mobilization chemotherapy. It was concluded that two cycles of HDM, 200 mg/m2, could be administered to approximately 70% of patients under the age of 66 with multiple myeloma in a median interval of 70 days, with improvement in CR rates.

Enhanced accuracy and reproducibility in reporting of lung scintigrams by a segmental reference chart

The diagnostic probability of pulmonary embolic disease is based on the recognition of unmatched segmental perfusion defects. Although interobserver and intraobserver reproducibility have been studied, accuracy has been an elusive goal due to the lack of a gold standard. We investigated the accuracy and reproducibility of reporting in a virtual scintigraphic model of the lungs, with and without the use of a lung segmental reference chart.

METHODS

A Monte Carlo package was used to model lung scintigraphy from a digital phantom of the human lungs. An ideal lung segmental reference chart was created from the phantom. Five experienced nuclear medicine physicians reported a set of all possible defects involving 100% of a segment, without and with the chart. A further set of defects involving 45%-55% of a segment in the lower lobes was investigated using the chart.

RESULTS

There was a significant improvement in accuracy (from 48% to 72%) and intraobserver agreement (from 61% to 77%) with the chart. The accuracy of reporting defects in the upper and middle lobes was consistently better than that in the lower lobes. There was no significant difference between the accuracy of reporting large defects and that of reporting moderate defects in the lower lobes.

CONCLUSION

The lung segmental reference chart significantly improves both the accuracy and reproducibility of reporting lung scintigrams; however, although reporting in the lung bases is improved, absolute accuracy is substantially less than that in the upper and middle lobes. This emphasizes the need for caution because the lung bases are the most common site of embolic disease.

Personality profiles of male and female positive role models in medicine

This study was designed to investigate the personality profile of positive role models in medicine. Participants were a national sample of 188 physicians (164 men, 24 women) who had been nominated by the chief executive officers of their institutions as positive role models and who completed the Revised NEO Personality Inventory. Compared to the general population, these 188 male and female positive role models in medicine scored higher on Conscientious factor, and on Achievement Striving, Activity, Competence, Dutifulness, Trust, Assertiveness, and Altruism facets, but they scored lower on the Vulnerability facet than the general population. In addition, the male role models scored significantly higher than men in the general population on the Agreeableness factor, and the female role models obtained significantly higher scores than the population norms on Extraversion and Openness factors, and on Feelings, Ideas, Positive Emotions, Values, Warmth, Aesthetics, and Fantasy facets. The female role models scored far below their sex-related norms on Neuroticism factor and on Angry Hostility facet. Comparisons between the male and female role models showed that the female role models scored higher on the Openness factor, and on the Feelings, Positive Emotions, Aesthetics, and Fantasy facets of personality. Implications in medical education and in explaining, assessing, and improving the qualities that contribute to professional success and in promoting the concept of "positive medicine" are discussed.

Variability of perceived defect size in virtual lung scintigraphy

The diagnosis of pulmonary embolism is based on the presence of mismatched segmental or subsegmental defects. An important axiom is the classification of defect sizes into small, moderate and large. Little information about the recognition and classification of such defects has been published. We undertook a study of the perception of defect size using a model of the virtual scintigraphic anatomy of the lungs to address this issue.

METHODS

Segmental anatomy of the lungs was modeled with CT, cadaveric lungs and standard anatomical tests. The emission, scatter and attenuation of photons were modeled within these virtual lungs and the surrounding tissues. Single segmental lesions, each 100% of a segment, were created in eight projections and submitted for blinded reporting by four experienced nuclear medicine physicians to obtain their assessment of the size of each defect on two occasions.

RESULTS

Of the 144 defects submitted for reporting, 15% were reported as <25% of a segment, 35% were reported as 25%-75% and 50% were reported as 75%-100%. The accuracy of each reporter and the intraobserver agreement were calculated; the weighted kappa value ranged from 0.34 to 0.60. The segmental defects that were most likely to be underestimated in size were in the right lower lobe.

CONCLUSION

It is clear that segmental defect sizes were underestimated, particularly in the right lower lobe. Although the intraobserver agreement in reporting was fair, the accuracy of estimation was only 50%. The variability and inaccuracy might be reduced by the use of a guide to segmental anatomy.

Optimization of the scintigraphic segmental anatomy of the lungs

Accurate and reproducible reporting of lung scintigraphy is predicated on a sound knowledge of the segmental anatomy of the lungs. A limited amount of hard data exists about the true segmental anatomy of the lungs. A virtual model of human lungs was created using a CT-based dataset and a Monte Carlo simulation technique to examine the optimal projections for the visualization of each segment in the lungs.

METHODS

Segmental anatomy of the lungs was modeled using CT, cadaveric lungs and standard anatomical texts. The emission, scatter and attenuation of photons was modeled within these virtual lungs and the surrounding tissues. Single segmental lesions were created in eight projections and submitted for blinded reporting to four experienced nuclear medicine physicians to obtain the best views for each segment.

RESULTS

The anterior and posterior oblique projections yielded the best views for 10 of 18 segments, with the laterals contributing four views, the anterior contributing two views and the posterior contributing one view. The majority of basal segments (six of nine) were best seen in the anterior and posterior oblique projections.

CONCLUSION

This model overcomes the major problems associated with experimentation in the normal human and has the potential to provide answers to the major problems of scatter, attenuation and "shine-through" in lung scintigraphy.

Creating and implementing guidelines on caring for difficult patients: a research utilization project

Difficult patients challenge the resourcefulness of nurses. Considering the results of a focus group study, guidelines are designed for the care of difficult patients. Four case studies present the use of the guidelines, including interventions and outcomes.

Induction, mobilization of peripheral blood stem cells (PBSC), high-dose chemotherapy and PBSC infusion in patients with untreated stage IV breast cancer: outcomes by intent to treat analyses

We investigated the outcomes of patients with breast cancer undergoing induction chemotherapy, mobilization of peripheral blood stem cells (PBSC) and high-dose chemotherapy (HDC) with PBSC infusion. One hundred and fourteen patients with untreated stage IV breast cancer, with a median age of 46 years (range 24-62), were entered on a phase II trial consisting of; (1) doxorubicin, 5-flurouracil, methotrexate (AFM) x 4 courses at 2 week intervals; (2) cyclophosphamide (4 g/m2), etoposide (600 mg/m2), cisplatin (105 mg/m2) (CEP), filgrastim (6 micrograms/kg/day) and PBSC collection; (3) cyclophosphamide (6 g/m2), thiotepa (500 mg/m2), carboplatin (800 mg/m2), (CTCb) followed by PBSC infusion. All patients received AFM, 107 (94%) received CEP, 93 (82%) received CTCb and PBSC as per protocol and 99 (87%) ultimately received HDC and PBSC. There was one infectious death after AFM and all other deaths were associated with progressive disease. Fifty-two patients (46%) are alive, 21 (18%) without progression, at a median 31 months (range 22-47). The probabilities of survival and progression-free survival at 3.5 years were 0.40 and 0.17, respectively. All 62 patients with visceral disease and/or a prior history of doxorubicin adjuvant therapy have relapsed or progressed. We conclude that the sequential administration of AFM, CEP and CTCb followed by PBSC resulted in long-term PFS only in patients who were NED, had bone-only disease or had lymph node or soft tissue disease with or without bone disease. Other strategies, aimed at improving responses to initial therapy, improving HDC regimens and/or developing immunomodulatory therapies, will be necessary to improve PFS for patients who fail doxorubicin adjuvant or who have visceral disease.

Physical properties and use of pertechnegas as a ventilation agent

Pertechnegas, a variant of technegas, produces similar ventilation images with a much increased clearance rate. This work aims to determine the properties of pertechnegas and its use as a ventilatory agent.

METHODS

Fourteen men and 11 women were scanned for PE, after pertechnegas ventilation. Six were reimaged with technegas within 1 wk. Studies were reported according to PIOPED criteria. Pertechnegas samples were analyzed by transmission electron microscopy (TEM), cascade impaction (CI), aerosol mobility analysis (AMA), Fourier transform mass spectrometry (FTMS), x-ray photoelectron spectroscopy (XPS), paper strip (PC) and gas chromatography (GC).

RESULTS

Post-test probabilities were normal in 5, low in 8, high in 5 and indeterminate in 7. There were 15 Grade 1, 6 Grade 2 and 4 Grade 3 studies. All Grade 3 patients had FEV1 < 1.5 liters, 3 with rates < 1.0 liter. Patients with high probability had proven deep venous thrombosis in three by venography and in one by doppler. TEM identified 0.3 micron salt particles. CI demonstrated a 7-min time to half clearance from the chamber for particles in the < 0.1 micron range. AMA indicated all particles were < 0.032 micron when salt was excluded. Pertechnegas behaves in PC as pertechnetate, GC demonstrated CO levels below 516 ppm. CO2 concentrations were 0.146 +/- 0.0009%. FTMS found molecular pertechnetate species including 99TcO3(OH)+, Na99TcO3(OH)3+ and Na99TcO3(OH)3+. XPS confirmed that these Tc species exist in oxidation state +7.

CONCLUSION

Comparison with technegas images in the follow-up group proved equivalent in the first five views, but indistinct lung boundaries and a high background activity characterized the final anterior images. The active component of pertechnegas is molecular pertechnetate.

Structural organization and developmental expression of the protein isoaspartyl methyltransferase gene from Drosophila melanogaster

A protein carboxyl methyltransferase activity (PCMT) with a specificity for age-damaged protein D-aspartyl and L-isoaspartyl residues (E.C. 2.1.1.77) has been identified and cloned in Drosophila. The Drosophila gene was localized by chromosome in-situ hybridization to region 83AB of the third chromosome. The methyltransferase coding sequence is distributed among four exons within a 1.4-kb segment of the genome; it predicts a polypeptide of 226 amino acids that is 55% identical to the mouse enzyme. When expressed in bacteria, the Drosophila protein exhibits PCMT activity. A single 1.4-kb Pcmt transcript is detected in RNA preparations from embryos, larvae, pupae and adults. The abundance of the transcript, which is lowest in larvae and highest in adults, parallels the specific activity of the enzyme measured in extracts from the same developmental stages. It has been proposed that the PCMT initiates the repair of structurally damaged cellular proteins. The constitutive expression of PCMT and the relatively high level of expression in postmitotic adult cells suggest that PCMT activity is required through development, but acquires additional significance in aging tissues.

Thoracoscopic laser bullectomy: a prospective study with three-month results

One hundred forty-one patients were prospectively enrolled in a study of contact-tip laser bullectomy at four institutions. Ninety-one have had both preoperative and postoperative testing at 3 months. Nonsmoking patients with disabling dyspnea at less than 50 yards and with a forced expiratory volume in 1 second of 35% or less were enrolled. Testing included formal pulmonary function tests, arterial blood gasses, computed tomographic scans, ventilation/perfusion scans, echocardiograms, electrocardiograms, 6-minute walk testing, transdiaphragmatic pressures, and quality of life and dyspnea index questionnaires. A modest 16% improvement was noted in forced expiratory volume in 1 second (0.69 to 0.80 L), and there was a 29% improvement in 6-minute walk distances (655.2 to 846.3 feet). Oxygen use was completely discontinued in 16%. Risk factors for mortality included age, 6-minute walk distances, low diffusing capacity for carbon monoxide, high carbon dioxide tension, and high base excess. Minor improvement was judged from the dyspnea index and the Medical Outcome Study Short Form-36. Preoperative predictors of good outcome included heterogeneous disease, lack of carbon dioxide retention, and no emaciation (weight < 40 kg). Comparison of our results with those in the literature suggests that the improvement seen with the contact neodymium:yttrium-aluminum-garnet laser is not as good as that provided by the stapled techniques for volume reduction.

The use of the iSTAT portable analyzer in patients undergoing cardiopulmonary bypass

OBJECTIVE

To evaluate the utility of the iSTAT blood analyzer, a bedside device for hematocrit, sodium, potassium, and glucose measurement during cardiopulmonary bypass (CPB).

METHODS

Forty patients scheduled for elective CPB were evaluated prospectively. In addition to using the iSTAT analyzer, blood samples were analyzed at four time points: following induction of anesthetic, 10 min. after initiation of CPB, 60 min. after initiation of CPB, and following heparin neutralization by protamine. Blood glucose concentration was measured by the hospital laboratory using a Kodak Analyzer and by a glucose meter, electrolytes were evaluated by the Kodak Analyzer and BGE (a device which is commonly used for "satellite laboratory" determinations of electrolyte and blood gas results), and hematocrit samples were measured by the hospital laboratory using an NE 8,000 and a centrifuge. The means and standard deviations of the differences between the methods were calculated.

RESULTS

The hematocrit values determined by the iSTAT machine, when adjusted for the level of total protein (according to manufacturer's directions), differed from the laboratory values by 0.53 +/- 1.46 percentage points. An alternative to measuring total protein and making the adjustment is simply adding 1% to the hematocrit in the pre-CPB period and 3% on-CPB or post-CPB, which we found to yield values that differed from the laboratory by 0.52 +/- 1.42 percentage points. For all four tests (hematocrit, sodium, potassium, and glucose) the iSTAT had a similar relationship to the laboratory values as did the other commonly used means (centrifuge, BGE, and glucose meter) of clinical evaluation.

CONCLUSION

In summary, we found that in patients undergoing CPB, the iSTAT values agreed sufficiently well with standard laboratory values and that the iSTAT instrument can be relied upon for bedside measurements.

Differential autoantibody responses to thyroid peroxidase in patients with Graves' disease and Hashimoto's thyroiditis

In order to examine the specificity of the autoantibody response to thyroid peroxidase (TPO, previously identified as thyroid microsomal antigen) in autoimmune thyroid disease, we examined reactivity of sera from 45 Hashimoto's and 48 Graves' patients to native thyroid microsomes, denatured and reduced human TPO and several recombinant fragments of human TPO corresponding to amino acids 457-933 of the native protein. Both Graves' and Hashimoto's sera bound native, denatured and reduced TPO at significantly greater rate than normal controls, and no differences were noted between the two disorders in binding to these forms of the autoantigen. Binding was also noted to two recombinant fragments of TPO, corresponding to amino acids 513-633 and 633-933 in TPO. The frequency of autoantibodies to the TPO AA(633-933) region was not significantly different in Hashimoto's vs. Graves' disease patients (58% vs. 65% respectively), and appeared to relate to evidence of glandular inflammation in the Graves' patients (presence of anti-thyroglobulin antibodies and elevated anti-microsomal antibody levels). In contrast, antibodies to the TPO AA(513-633) fragment were significantly more common and of higher titer in Hashimoto's vs. Graves' disease patients, and did not correlate with any measure of glandular inflammation. These results identify two specific regions of TPO autoantibody binding and indicate that there are differences in the autoantibody response to TPO in Hashimoto's and Graves' diseases.

The Cape Mendocino, California, Earthquakes of April 1992: Subduction at the Triple Junction

The 25 April 1992 magnitude 7.1 Cape Mendocino thrust earthquake demonstrated that the North America-Gorda plate boundary is seismogenic and illustrated hazards that could result from much larger earthquakes forecast for the Cascadia region. The shock occurred just north of the Mendocino Triple Junction and caused strong ground motion and moderate damage in the immediate area. Rupture initiated onshore at a depth of 10.5 kilometers and propagated up-dip and seaward. Slip on steep faults in the Gorda plate generated two magnitude 6.6 aftershocks on 26 April. The main shock did not produce surface rupture on land but caused coastal uplift and a tsunami. The emerging picture of seismicity and faulting at the triple junction suggests that the region is likely to continue experiencing significant seismicity.

Thoracoscopic stapled resection for spontaneous pneumothorax

Video-assisted thoracoscopy has recently evolved as an alternative to thoracotomy for several thoracic disorders. Spontaneous pneumothorax may be ideally suited for thoracoscopic management. Stapling of apical blebs and pleurodesis or pleurectomy can now be performed thoracoscopically in a fashion identical to the standard operation done through a lateral or axillary thoracotomy. We compared our results with thoracoscopic management of spontaneous pneumothorax in 26 patients (group I) with a group of 20 patients previously subjected to axillary thoracotomy (group II). Indications for operation, sex distribution, and average age (group I, 32.3 years; group II, 33.7 years) were comparable. Hospital stay was less in group I (2.88 +/- 0.99 days versus 4.47 +/- 1.07 days; p = 0.07), as was the use of parenteral narcotics after 48 hours (2/26 = 7.7% versus 14/20 = 70%; p = 0.01). There have been no recurrences to date (mean follow-up, 8 months) in the thoracoscopic group. Video-assisted thoracoscopic management of spontaneous pneumothorax allows performance of the standard surgical procedure while avoiding the thoracotomy incision. Video-assisted thoracoscopic management is safe and offers the potential benefits of shorter hospital stays and less pain.