Thallium-201 scintigraphy–a predictor of tumour necrosis in soft tissue sarcoma following preoperative radiotherapy?

AIM

Thallium-201 (Tl-201) scintigraphy in patients with malignant soft tissue tumours was evaluated to determine whether the images correlated with histological response to preoperative radiotherapy.

METHODS

We studied 54 patients, median age 32 (range 17-84) years, with non-metastatic, malignant soft tissue tumours diagnosed between 1996 and 2001. Thirty-eight patients had unoperated tumours and 16 patients had previous incomplete excisions. All patients received preoperative radiotherapy followed by surgery. No patient received chemotherapy as part of their initial management. Qualitative analyses of early phase (30 min) and late phase (4 h) Tl-201 scintigraphic images before and after preoperative radiotherapy were compared with the degree of tumour necrosis determined histologically.

RESULTS

In the previously unoperated group, all 38 patients had increased TL-201 uptake in the late phase of scanning prior to radiotherapy suggesting metabolically active tissue. In the previously excised group 11 patients had increased Tl-201 uptake in the late phase of scanning prior to radiotherapy. Following radiotherapy, patients with Tl-201 retention on late phase scans had a lower rate of necrosis than patients with minimal retention, p<0.0001. Following radiotherapy, 28 of 29 patients with minimal uptake on the late phase had 80% or more necrosis, while 24 of 25 patients with increased uptake on the late phase had less than 80% necrosis (p<0.0001). Patients with previously excised tumours who had thallium retention following radiotherapy demonstrated evidence of residual disease at surgery. All patients with incompletely excised tumours who had no thallium retention on late phase scanning after radiotherapy demonstrated no evidence of residual disease at surgery.

CONCLUSION

Thallium scintigraphy is a readily available investigative tool, which when used in conjunction with other imaging modalities in the assessment of primary and incompletely excised malignant soft tissue tumours, may predict histological tumour response to preoperative radiotherapy.

The quality of a simulation examination using a high-fidelity child manikin

PURPOSE

Developing quality examinations that measure physicians' clinical performance in simulations is difficult. The goal of this study was to develop a quality simulation examination using a high-fidelity child manikin in evaluating paediatric residents' competence about managing critical cases in a simulated emergency room. Quality was determined by evidence of the reliability, validity and feasibility of the examination. In addition, the participants' responses regarding its realism, effectiveness and value are presented.

METHOD

Scenario scripts and rating instruments were carefully developed in this study. Experts were used to validate the case scenarios and provide evidence of construct validity. Eighteen paediatric residents, 'working' as pairs, participated in a manikin-based simulation pre-test, a training session and a post-test. Three independent raters rated the participants' performance on task-specific technical skills, medications used and behaviours displayed. At the end of the simulation, the participants completed an evaluation questionnaire.

RESULTS

The manikin-based simulation examination was found to be a realistic, valid and reliable tool. Validity (i.e. face, content and construct) of the test instrument was evident. The level of inter-rater concordance of participants' clinical performance was good to excellent. The item analysis showed good to excellent internal consistency on all the performance scores except the post-test technical score.

CONCLUSIONS

With a carefully designed rating instrument and simulation operation, the manikin-based simulation examination was shown to be reliable and valid. However, a further refinement of the test instrument will be required for higher stake examinations.

Physicians must participate in establishing standards of care

Dr. Ubel has raised an issue with no easy answers. Rationing and the perception that we must ration will be with us for the foreseeable future. Physicians must participate at all levels in the process to achieve consistent and appropriate care. The standard of care provided should be referenced to a societal norm, which physicians must help to establish. Physicians must then use that standard in individual patient care. This is rationing, and the medical system cannot exist without it.

Disability in an urban black community in Zimbabwe

PURPOSE

This study was undertaken to establish which health conditions are primarily responsible for disability and morbidity in a high-density area in Harare, Zimbabwe.

METHOD

House-to-house screening visits were followed up by medical examination and interview of those identified as having a functional limitation.

RESULTS

Information was obtained during screening on 10,839 residents. Of these, 608 were examined by medical professionals. The rate of disability/morbidity was 5.6% for the whole sample. Headaches and migraine were the most common problem. These were followed by back pain, hypertension and osteoarthritis. HIV/AIDS was the fifth most common condition. Depression, based on responses to a screening tool, was evident in one-third of the subjects. Common activity limitations included difficulty with the performance of housework activities and with walking. HIV/AIDS resulted in the most severe activity limitation, in that cognitive functions were also affected.

CONCLUSION

The middle-aged and elderly with osteoarthritis and young women with depression constitute vulnerable groups who are not in a position to demand services. The older women particularly need assistance as they are bearing the double burden of their own degenerative conditions and the results of the HIV/AIDS pandemic.

Wound complications following pre-operative radiotherapy for soft tissue sarcoma

AIMS

We analysed wound complications in 43 patients with soft tissue sarcoma who were treated with combined pre-operative radiotherapy and surgery.

METHODS

All patients received the same protocol of pre-operative radiotherapy at our institution.

RESULTS

Thirty-six (84%) patients developed acute skin toxicity following radiotherapy. After wide local excision, 15 patients required primary soft tissue reconstruction with vascularized muscle transfer and four patients underwent free skin flap to enable wound closure as part of their primary surgery. Nineteen patients (44%) developed post-operative wound complications including 10 (23%) patients who required an additional surgical procedure. Four (27%) patients developed flap necrosis in a group of 15 who underwent primary vascularized soft tissue transfer. All required a second vascularized muscular flap. One elderly patient, who had grade 3 acute radiation skin toxicity, had an arterial graft and total hip arthroplasty for a femoral artery aneurysm and an avascular necrosis of the hip, respectively. In our series, age (> or = 40 years) was the only impact factor influencing wound complication after surgery following radiotherapy (P=0.06).

CONCLUSIONS

Site of tumour, radiation field size, surgical resection volume, grade of acute radiation toxicity, co-morbidity, and smoking were not demonstrated to have predictive value in wound complication following pre-operative radiotherapy. Although previous papers suggested that vascularized soft tissue transfer could be useful reducing wound morbidity, our results could not confirm this.

Hypersensitivity reactions during therapy with the nucleoside reverse transcriptase inhibitor abacavir

BACKGROUND

Hypersensitivity reactions consist of a variable group of clinical findings and have been described for a wide variety of chemical compounds.

OBJECTIVE

This review characterizes the clinical profile of hypersensitivity to the nucleoside reverse transcriptase inhibitor abacavir sulfate.

METHODS

We performed a retrospective medical review of pooled adverse events data from approximately 200,000 patients who received abacavir in clinical trials, through expanded-access programs, or by prescription from 1996 through 2000. Screened cases of hypersensitivity were classified as either definitive or probable. Definitive cases were identified when initial symptoms resolved on interruption of abacavir therapy and returned on reintroduction of abacavir therapy.

RESULTS

A total of 1803 cases were identified, 1302 in the 30,595 patients participating in clinical trials or the expanded-access program and 501 in patients from the post-marketing experience. On review, 176 (9.8%) of these cases were considered definitive and the remainder probable. Based on the 1302 cases identified in clinical trials or the expanded-access program, the calculated incidence of hypersensitivity was 4.3%. Symptoms reported in > or = 20% of cases of this multiorgan reaction included fever, rash, malaise/fatigue, and gastrointestinal symptoms such as nausea, vomiting, and diarrhea, among others. Respiratory symptoms occurred in 30% of cases and included dyspnea (12%), cough (10%), and pharyngitis (6%). In 90% of cases, hypersensitivity reactions occurred within the first 6 weeks after initiation of abacavir (median time, 11 days); after an initial reaction, rechallenge with abacavir resulted in the reappearance of symptoms within hours of reexposure. Hypotension was present in 25% of these rechallenge reactions. Among patients who received abacavir in clinical trials, the mortality rate was 0.03% (3 per 10,000 patients).

CONCLUSIONS

Hypersensitivity to abacavir is an idiosyncratic reaction and a distinct clinical syndrome characterized predominantly by systemic involvement. It can be expected to appear as a treatment-limiting event in approximately 5% of patients. The appearance of clinical symptoms consistent with this syndrome mandates immediate discontinuation of abacavir. Hypersensitivity to abacavir is an absolute contraindication to subsequent treatment with any formulation that includes this agent.

Do nurses go on courses just to collect tickets?

The question ‘Which course shall I go on next?’ has become a familiar cry in hospital wards throughout the country. When the postregistration education and practice (PREP) guidelines were introduced it was never envisaged that this would create a new ethos of collecting certificates. There is a fundamental misconception among many nurses that in order to meet their PREP requirements they need to jump constantly from one course to the next.

One-step disposable chambers for sperm concentration and motility assessment: how do they compare with the World Health Organization's recommended methods?

The World Health Organization suggests that 'one-step' type disposable chambers lack the accuracy and precision of the haemocytometer method for assessing sperm concentration. The purpose of this particular study was to compare sperm concentration measurements and motility using the Neubauer((R)) haemocytometer with those obtained using three 'one-step' methods: the Microcell((R)) slide, Leja((R)) slide and a plain glass slide with a 22x22 mm coverslip. A total of 200 sperm concentration measurements and 100 motility assessments were performed on all chambers. Paired comparisons showed enormous discrepancies between the counts, particularly between the Neubauer((R)) and other chambers (P < 0.0001). This discrepancy was less pronounced in oligozoospermic samples, and samples with low (<30% progression) motility but more pronounced in normozoospermic samples and those with good motility (>50% progression). In addition, concentration assessments from a fresh undiluted and unfixed semen sample on the Microcell((R)) slide were found to be significantly lower than both fixed counts on the same slide (P = 0.011) and the initial laboratory reading on the Neubauer((R)) chamber (P = 0.009). No differences were observed in progressive motility between the different chambers and a plain glass slide. There appears to be little comparison between the haemocytometer and either re-useable or disposable one-step chambers. The unfortunate consequence of this is that diagnostic semen analysis and guidelines for allocation of patients to appropriate treatment groups will vary from centre to centre, depending on the method used and may, on occasion, be erroneous.

Tornado at Pine Lake, Alberta — July 14, 2000: Assessment of the emergency medicine response to a disaster

Les programmes de médecine et de résidence négligent souvent l’enseignement de la médecine de catastrophe, mais lorsqu’une catastrophe se produit, c’est le personnel de médecine d’urgence qui se retrouve au front. Les médecins d’urgence doivent se familiariser avec le plan de sinistre de leur hôpital et être prêts à participer à l’opération de sauvetage.

The high oleate trait in the cultivated peanut [Arachis hypogaea L.]. I. Isolation and characterization of two genes encoding microsomal oleoyl-PC desaturases

Plant oils rich in oleate are considered superior products compared to oils rich in polyunsaturated fatty acids. Peanut (Arachis hypogaea L.) is one of the major oilseed crops, and high oleate mutant varieties with as much as 85% oleate have been reported. We examined the possibility that this mutant phenotype resulted from reduction in the activity or the transcript level of microsomal oleoyl-PC desaturase. Two independently generated high oleate mutants, M2-225 and 8-2122, and their partially isogenic lines with a normal oleate phenotype were used in this study. Two cDNA sequences coding for microsomal oleoyl-PC desaturases, ahFAD2A and ahFAD2B, have been isolated from the developing peanut seed with a normal oleate phenotype. Cultivated peanut is an allotetraploid, and sequence comparisons with the genes from the putative diploid progenitor species suggested that ahFAD2A and ahFAD2B are non-allelic, but homeologous genes originating from two different diploid species. Northern analysis showed that the transcripts of oleoyl-PC desaturases are highly abundant in both normal and high oleate peanut seeds in the second stage of development. Differential digestion of the RT-PCR products revealed a restriction site polymorphism between ahFAD2A and ahFAD2B, and allowed us to examine the level of transcript expressed from each gene. The results indicate that ahFAD2A is expressed in both normal and high oleate peanut seeds, but the steady state level of the ahFAD2B transcript is severely reduced in the high oleate peanut varieties. These data suggested that the reduction in ahFAD2B transcript level in the developing seeds is correlated with the high oleate trait.

The high oleate trait in the cultivated peanut [Arachis hypogaea L]. II. Molecular basis and genetics of the trait

A peanut variety with high oleate content has previously been described. When this high oleate variety was used in breeding crosses, the F2 segregation ratio of high oleate to normal oleate progeny was 3:1 or 15:1 depending on the normal oleate varieties used in the crosses. These data suggested that the high oleate trait is controlled by two recessive genes, and some peanut varieties differ from the high oleate variety by mutations in one gene, while others differ by mutations in two genes. The objective of this study was to understand the molecular nature of the high oleate trait and the various segregation patterns. In the previous paper in this issue, we reported that the level of transcripts expressed by one (ahFAD2B) of two homoeologous genes for oleoyl-PC desaturases in cultivated peanut is significantly reduced in high oleate varieties. In this report, we examined gene expression by RT-PCR/restriction digestion in a cross that shows a one-gene segregation pattern for the high oleate trait. Our data showed that the severely reduced level of ahFAD2B transcript correlates absolutely with the high oleate phenotype in this cross, suggesting that the single gene difference is correlated with the ahFAD2B transcript level. When we tested the enzyme activity of the proteins encoded by ahFAD2A and ahFAD2B by expression of the cloned sequences in yeast, only the ahFAD2B gene product showed significant oleoyl-PC desaturase activity. These data, combined with the observation that ahFAD2A shows a change (D150N) in a residue that is absolutely conserved among other desaturases, raised the possibility that the ahFAD2A in these normal and high oleate lines is a mutant allele. In support of this hypothesis, we found that another ahFAD2A allele in a normal oleate peanut line does not have the D150N change. This peanut line displays a two-gene-segregation pattern for the high oleate trait. In conclusion, our results suggest that a mutation in ahFAD2A and a significant reduction in levels of the ahFAD2B transcript together cause the high oleate phenotype in peanut varieties, and that one expressed gene encoding a functional enzyme appears to be sufficient for the normal oleate phenotype.

In vivo caries-like lesion prevention with argon laser: pilot study

OBJECTIVE

This clinical pilot study was conducted to investigate the effectiveness of argon laser irradiation to reduce demineralization or loss of tooth structure in vivo.

SUMMARY BACKGROUND DATA

In vitro research previously demonstrated the ability of argon laser irradiation to reduce demineralization or loss of tooth structure.

METHODS

Using the Ogaard model of producing demineralization, the experimental teeth were irradiated with argon laser of 250 mW (producing approximately 12 J/cm2) prior to banding. Polarized light evaluation of the sectioned, extracted teeth was used to determine the amount of demineralization.

RESULTS

Results showed a 29.1% reduction in demineralization in the experimental teeth as compared to the bilateral control teeth.

CONCLUSION

Low-power argon laser irradiation significantly reduced demineralization clinically.

Different cup migration in rheumatoid arthritis and arthrosis: a radiographic analysis of 127 uncemented acetabular cups

We compared retrospectively the radiographic migration profiles of 82 acetabular components in 61 patients having rheumatoid arthritis with those of 45 hips having arthrosis who underwent a standardized technique of cementless arthroplasty with the Zweymüller prosthesis (Alloclassic). We used a modification of Dickob's technique of digital migration analysis that corrects for magnification errors and horizontal pelvic tilt. The rheumatoid patients were stratified as having oligoarticular, polyarticular, or mutilating arthritis. The overall rate of acetabular loosening in rheumatoid hips after mean 88 (26-117) months was 4%. Loosening was seen only in cases with mutilating arthritis and acetabular protrusion, where the direction of cup migration was also clearly different from that detected in the other types of rheumatoid arthritis and in arthrosis. The different patterns of cup migration in cementless hip replacement for rheumatoid arthritis, depending on disease severity, is of importance when comparing outcome of total hip arthroplasty in rheumatoid patients.

Role of the helper component in vector-specific transmission of potyviruses

Four aphid species were tested for their ability to transmit tobacco etch (TEV) and turnip mosaic (TuMV) potyviruses. Myzus persicae and Aphis gossypii transmitted both viruses efficiently from infected plants, whereas Lipaphis erysimi transmitted only TuMV and Myzus ascalonicus was a poor or non-transmitter of either virus. Similar electrically monitored probing patterns were produced by M. persicae, L. erysimi and M. ascalonicus, ruling out behavioural differences as the cause of differential transmission. Transmission results similar to those from infected plants were obtained when these aphids acquired homologous virus/helper component (HC) mixtures through membranes. With heterologous virus/HC mixtures, M. persicae remained a highly efficient vector and M. ascalonicus a non-vector, but L. erysimi became an efficient vector of TEV if acquired in the presence of TuMV HC and A. gossypii transmitted both viruses less efficiently when acquired with TuMV HC. Transmission was highly correlated with the retention of virus in the stylets, as determined by autoradiography of 125I-labelled virions. The results show that constituent(s) of or in the food canal of different aphid species differ in their ability to interact with specific HCs, leading to qualitative or quantitative differences in ability to retain and subsequently transmit specific potyviruses.

Is clozapine safe in the elderly?

OBJECTIVE

The aim of this paper is to assess the risk/benefit ratio of clozapine in the elderly.

METHOD

MedLine and Internet searches, followed by cross-checking for further articles, identified the references. Reports on efficacy as well as side effects were examined. Five psychogeriatric patients treated by the authors are presented.

RESULTS

The review of the literature highlighted the lack of studies on the use of clozapine in the elderly. Retrospective studies and case reports dominate. There is only one double-blind placebo-controlled study of six patients extant. Although efficacy seemed to parallel that in the younger age groups, the incidence of leukopenia, agranulocytosis, postural hypotension and confusion was greater in the elderly. Two of the five patients reported by the authors developed agranulocytosis, bringing the Australian experience of agranulocytosis in patients over 65 years of age to 4/55.

CONCLUSION

The risk/benefit ratio in the elderly is distinctly higher than found in the younger population. With specific reference to agranulocytosis alone, the frequently quoted risk of 1% for patients is likely to be 5-10 times higher in the over 65 population. Caution is advised when prescribing clozapine in the psychogeriatric population.

Microchips versus stethoscopes, part 2: Revisiting OSCAR at the Foothills Hospital

Several years have passed since the Foothills Hospital in Calgary installed a multi-million-dollar computerized patient-information system. When it arrived, the computer system known as OSCAR created controversy, anxiety and arguments among clinical caregivers who found it tedious, time consuming and cumbersome. Gregory Powell looks at how OSCAR has since changed the clinical landscape at Foothills.

Photophobia and lithium

CLINICAL PICTURE

We report the case of a 45 year old woman who developed photophobia after 6 months on lithium at non-toxic levels.

TREATMENT AND OUTCOME

Lithium was reintroduced twice and on both occasions this side-effect reoccurred within days.

CONCLUSIONS

Photophobia has only been described previously as a symptom of lithium intoxication.

Personality and psychosocial function after brain injury

A total of 74 brain-injured patients and 46 non-neurologically matched controls consecutively admitted to a specialist medical rehabilitation unit, were administered the 'Headley Court psychosocial rating scale' and four questionnaires examining personality traits of 'locus of control', 'use of humour', 'optimism' and 'easy-going disposition'. Both pre- and post-injury personality ratings were obtained. The relatives of all participants were sent the same scales. Personality changes are reported in each of the four areas; however, time post-injury appears to be a significant factor in the type of change reported; in this cross-sectional study, at 6 and 12 months post-injury, changes are noted in all variables except locus of control, whereas at 18 months post-injury only 'easy-going disposition' showed significant change, at 24 months post-injury changes were noted in all variables except optimism, and at 30 months post-injury no changes were noted. In the present study, examining a period of 2.5 years post-injury, the personality changes remain static once they have occurred. Despite widespread reports in the literature on the importance of pre- and post-trauma personality to good psychosocial functioning, the present study found that it was only an 'easy-going disposition' post-trauma that was consistently related to good psychosocial functioning. Reasons for this are discussed.