How to minimize inappropriate utilization of Accident and Emergency Departments: improve the validity of classifying the general practice cases amongst the A&E attendees

Studies have found that one-third to two-thirds of all patients attending Accident and Emergency (A and E) Departments could be managed appropriately by general practitioners (GPs). There is also evidence that referral to GPs can be acceptable to patients. The question of primary concern is screening non-urgent cases with high degrees of sensitivity (S), specificity (SP), and positive predictive value (PPV). This paper reports the findings of the validity (S, SP and PPV) of nurses and patients in triaging A and E visitors. A cross sectional study was conducted over a 1 year period and subjects were randomly selected from four A and E Departments located across the four principle geographic regions of Hong Kong by stratified, two-stage sampling. S, SP and PPVs were computed for both non-weighted and weighted conditions. The gold standard for defining the true urgency status of each selected patient was based on a review of the patient's record 3-21 days (or longer if necessary) following the A and E visit. The record review in each A and E was blinded and done independently by a panel of two (and if disagreement existed, three) senior emergency physicians who did not practice in the same hospital. The greatest weights would be for incorrect decisions with greatest impact on patients' well being. The most accurate unweighted nurses' triage classification had an average sensitivity of 87.8%, specificity of 83.9%, and a PPV of 70.1%. When weighted, the average sensitivity reduced to 75%, specificity to 65.7%, and PPV to 54%. The most accurate unweighted patients' self-triage classification yielded a sensitivity of 62.5%, specificity of 69.2%, and a PPV of 58.1%, and correspondingly reduced to 43.3, 49.2 and 38.6% if weights were applied. Validity of the derived patients' self-classifications was too inaccurate for practical use. Hong Kong's current use of a five-point urgency scale by nurses would be further refined for identifying non-urgent visitors. If a mechanism was put in place for additional screening on visitors with a borderline semi-urgent or non-urgent status, the nurses could safely reassign non-urgent patients to GP care. If implemented, a significant impact on hospital costs could be realized.

Facilitated loading of horizontal gels using a capillary comb loader

Manual loading of samples into horizontal gels, such as the agarose gels commonly used for DNA fragment sizing and quantification, is laborious and prone to errors. Manual-loading times for highthroughput gels can reach 10 min/gel, and human error can result in incorrect identification of samples because of reverse loading or other errors in the loading process. To reduce gel-loading times and to improve reliability, a novel comb has been developed that uses glass capillaries and hydrostatic pressure to simplify sample loading from microplates. Accurate sample metering is ensured by the uniform length and volume of the capillaries. The loaded comb is placed in the gel boat over a pre-cast agarose gel, and buffer is added to a reservoir at the top of the comb. Once the buffer rises over the ends of the capillaries, the samples are pushed into the wells by hydrostatic pressure. This technique was successfully demonstrated for a 24-lane comb. This capillary comb loader reduces loading time, maintains well-to-well uniformity, and retains the same geometry and appearance of manually loaded bands, making this loading method compatible with existing downstream processes and software for subsequent analysis of the gel image.

Cyclic AMP and cyclic GMP activate protein kinase G in cavernosal smooth muscle cells: old age is a negative factor

OBJECTIVE

To investigate protein kinase G-I (PKG-I) expression and activation in cavernosal smooth muscle cells (CSMC) of young and old rats.

MATERIALS AND METHODS

PKG-I expression in rat penis was examined by immunohistochemical staining, reverse transcription-polymerase chain reaction, and Western blot analysis. CSMC isolated from young (16-week-old) and old (28-month-old) rats were grown as monolayer cell cultures and treated with different dosages of cAMP or cGMP for different periods. Their proteins were then analysed for the expression of vasodilator-stimulated phosphoprotein (VASP), phosphorylated VASP (at serine 239), PKG-I, and protein kinase A (PKA).

RESULTS

PKG-I expression was detected in the vascular and CSMC of the rat penis. There was little or no difference in the level of PKG-I expression between young and old rats. Treatment of CSMC with different dosages of cAMP or cGMP did not change the expression levels of VASP throughout the entire test period (up to 24 h). In contrast, the level of VASP phosphorylation at S239, i.e. the level of PKG-I activation, depended on the dosages of cAMP and cGMP and on the duration of treatment. Prolonged treatment (24 h) with either cAMP or cGMP resulted in down-regulation of both PKG-I and PKA. While cAMP and cGMP produced very similar results in nearly every aspect, there was a difference in one test, in which cGMP produced much less activated PKG-I than cAMP in the CSMC of 28-month-old-rats.

CONCLUSIONS

For the first time we provide evidence for PKG-I activation in CSMC. Both cAMP and cGMP were capable of activating PKG-I in CSMC. Age seemed to compromise the ability of PKG-I in response to cGMP.

Human PDE5A gene encodes three PDE5 isoforms from two alternate promoters

Sildenafil improves erectile function by inhibiting the cGMP-catalytic activity of phosphodiesterase type V (PDE5). We used rapid amplification of cDNA Ends-polymerase chain reaction (RACE-PCR) to isolate three PDE5 isoforms from human corpus cavernosum. Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis on eight human cavernous tissue samples showed that all samples expressed the PDE5A1 at a lower level than the PDE5A2 isoform. Five samples expressed the PDE5A3 isoform at various levels while the other three did not. Analysis on non-penile tissues showed that all tissues expressed the A1 and A2 isoforms while only those that have substantial amounts of smooth muscle expressed the A3 isoform. Cloning and sequencing of the PDE5A gene showed that the isoform-specific 5'-ends of the PDE5 mRNAs are encoded from three alternative first exons arranged in the order of A1-A3-A2. Promoter activities were detected upstream from the A1-specific exon and in the intron preceding the A2-specific exon. The upstream PDE5A promoter is expected to direct the expression of all three PDE5 isoforms while the intronic PDE5A2 promoter only the A2 isoform. Both promoters were upregulated by increasing concentrations of either cAMP or cGMP. Several transcription factor AP2 and Sp1-binding sequences identified in the promoters are likely to be the mediators of cAMP/cGMP-responsiveness.

Age-related decrease of protein kinase G activation in vascular smooth muscle cells

Protein kinase G-I (PKG-I) activation is essential for vascular relaxation; however, its quantitative analysis in intact cells has been difficult. To overcome this difficulty, a monoclonal antibody, VASP-16C2, was recently developed that detects phosphorylated serine residue 239 of vasodilator-stimulated phosphoprotein (VASP), a substrate of PKG-I. In this study, we used this antibody to examine (i) possible functional differences between the alpha and beta isoforms of PKG-I, (ii) ability of cAMP to activate PKG-I, as compared to cGMP, the principal PKG-I-activating cyclic nucleotide, and (iii) time course and levels of PKG-I activation in vascular smooth muscle cells (VSMC) of young and old rats. We created COS-7 cell clones that overexpressed PKG-Ialpha or PKG-Ibeta, treated them with cAMP or cGMP, and analyzed their cell lysates for reactivity with VASP-16C2. The results showed that PKG-Ialpha phosphorylated VASP at a higher level than PKG-Ibeta, and cAMP was slightly weaker than cGMP in PKG-I activation. VSMC of young rats responded to cAMP or cGMP stimulation in a dose-dependent manner with increasing levels of PKG-I activation. The response was detected within 10 min and continued for at least 24 h. In contrast, VSMC of old rats showed no PKG-I activation during the first hour of cAMP or cGMP stimulation and, at 24 h these cells showed only low-level PKG-I activation. We propose that the reduced PKG-I activation may explain why vascular relaxation is decreased in older individuals.

The BH3 domain of BAD fused to the Antennapedia peptide induces apoptosis via its alpha helical structure and independent of Bcl-2

Since the over-expression of Bcl-2 is a common cause of multi-drug resistance, cytotoxic peptides that overcome the effects of Bcl-2 may be clinically useful. We harnessed the death-promoting alpha helical properties of the BH3 domain of BAD by fusing it to the Antennapedia (ANT) domain, which allows for cell entry (ANTBH3BAD). Treatment of 32D cells with the ANTBH3BAD peptide results in a 99% inhibition of colony formation. No significant toxicity is observed after treatment with ANT or BH3BAD alone. A mutant fusion peptide unable to bind Bcl-2 induces cell death as effectively as the wild-type ANTBH3BAD. Furthermore, 32D cells over-expressing Bcl-2 show no resistance to the ANTBH3BAD peptide. Therefore, the toxicity of the peptide was independent of the Bcl-2 pathway. We demonstrate that the toxicity of the peptide is due to its alpha helicity that disrupts mitochondrial function. Since this peptide overcomes major forms of drug resistance, it may be therapeutically useful if appropriately targeted to malignant cells.

BAD induces apoptosis in cells over-expressing Bcl-2 or Bcl-xL without loss of mitochondrial membrane potential

Inhibitors of Bcl-2 may be useful therapeutic agents for the treatment of a wide variety of malignancies including leukemia. A potential prototype of such a compound is the endogenous Bcl-2 and Bcl-xL binding protein BAD. Previous reports indicate that BAD can overcome the anti-apoptotic effect of Bcl-xL but not Bcl-2. If BAD cannot induce apoptosis in cells over-expressing Bcl-2, it would limit the application of molecules like BAD as novel anti-tumor agents. We report that transient transfection of BAD induced cell death in cells with and without over-expression of Bcl-2 or Bcl-xL. Forty-eight hours after transfection, BAD increased cell death in COS, COS Bcl-2, and COS Bcl-xL cells as demonstrated by decreased GFP expression, and an increase in the number of number of floating cells. In addition, BAD induced cell death in leukemic cell lines over-expressing Bcl-2 and Bcl-xL as determined by changes in luciferase activity. BAD-induced apoptosis was not accompanied by loss of mitochondrial membrane potential. Therefore, we conclude that transient transfection of BAD directly induces apoptosis in cells over-expressing Bcl-2 or Bcl-xL and validates the pursuit of molecules like BAD as novel therapeutic agents.

Morbidity patterns of non-urgent patients attending accident and emergency departments in Hong Kong: cross-sectional study

OBJECTIVES

To study the morbidity patterns of non-urgent patients utilising accident and emergency services and compare these patients with 'true' accident and emergency cases. To analyse the morbidity pattern of non-urgent cases over different time periods, and across different age groups.

DESIGN

A cross-sectional study completed over a 1-year period.

SETTING

Four accident and emergency departments in Hong Kong.

PATIENTS

Two thousand, four hundred and ten patients randomly selected from four accident and emergency departments.

MAIN OUTCOME MEASURES

The morbidity patterns by body system, according to the International Classification of Primary Care, were tabulated and analysed for 'true' accident and emergency cases versus non-urgent cases. The ten most frequent diagnoses for the 'true' accident and emergency and non-urgent cases were also compared. Further analysis of accident and emergency service utilisation was conducted comparing different age groups, and also different time periods.

RESULTS

Significantly more cases presenting to the accident and emergency service with respiratory and digestive problems were found to be non-urgent, rather than appropriate accident and emergency cases. In contrast, significantly more cases presenting with circulatory and neurological problems were appropriate cases for accident and emergency department management. The morbidity pattern for the ten most frequent diagnoses seen in non-urgent cases was noted to be similar to the Hong Kong general practice morbidity pattern for self-limiting conditions. Utilisation of accident and emergency services for acute self-limiting conditions was more marked in the late evening, and also among children and the younger population in general.

CONCLUSION

The utilisation of accident and emergency services by patients requiring a general practice service only, reflects problems in the primary health care delivery system. These may be solved by appropriate interfacing between general practitioners and other service providers, with the aim of providing seamless health care. Without revision of primary health care services, accident and emergency departments will continue to be used inappropriately by patients as an alternative to general practice care.

The Functional Pain Scale: reliability, validity, and responsiveness in an elderly population

OBJECTIVES

Because of difficulty experienced in assessing pain in frail older patients and the lack of pain assessment tools with standardization in the elderly, the Functional Pain Scale (FPS), an instrument incorporating both subjective and objective components to assess pain, was developed and evaluated.

DESIGN, SETTING, PARTICIPANTS, AND MEASURES

One hundred subjects more than 65 years old participated in the validity, reliability, and responsiveness (the clinical sensitivity of the instrument to change) testing of the Functional Pain Scale. Subjects were recruited from a geriatrics inpatient setting, a geriatrics outpatient setting, and a local hospice (residing in their homes). Ninety-four of the subjects completed all phases of testing. Reliability was tested using a test-retest format and a correlation matrix. Criterion-related validity was established as compared with the Visual Analog Scale (VAS), the Present Pain Intensity (PPI), the McGill Short Form Questionnaire (MPQ-SF), and the Numeric Pain Scale (NPS) instruments. Responsiveness for the FPS, the VAS, the PPI, the MPQ-SF, and the NPS instruments was determined using five previously described techniques: effect size, standardized response means, relative efficiency, direct comparison of t test scores, and direct comparison of P values. A cumulative index was developed to rank each scale. Cumulative responsiveness index scores were based on individual scale performance for each separate responsiveness test. The lowest score in the cumulative responsiveness index indicated the most responsive scale.

RESULTS

Interrater reliability for instruments tested exceeded 0.95 for all instruments tested. Validity testing showed high correlations as well (r = 0.62, r = 0.85, r = 0.80, r = 0.90 for the VAS, the PPI, the MPQ-SF, and the NPS respectively). Responsiveness evaluated overall by the responsiveness index was best for the Functional Pain Scale (7) followed by the Visual Analog Scale (12), the Present Pain Intensity (13), the McGill Pain Questionnaire-Short Form (19), and the Numerical Pain Questionnaire (24).

CONCLUSIONS

The Functional Pain Scale was determined to be reliable, valid, and responsive. The responsiveness of the Functional Pain Scale was superior to the other instruments tested. The Functional Pain Scale is an acceptable instrument for assessing pain in older adults and may reflect changes in pain better than other instruments tested. Further testing in other populations is warranted.

Measurement of MAP kinase activation by flow cytometry using phospho-specific antibodies to MEK and ERK: potential for pharmacodynamic monitoring of signal transduction inhibitors

Cancer cells frequently show abnormal signaling via the mitogen activated protein kinase (MAP kinase) pathway due to increased activity of surface receptors for growth factors, or as a result of ras mutations. The development of potent anti-cancer agents that target this pathway prompts the need for analytical methods that allow pharmacodynamic monitoring of drug effects in patients during early phase clinical trial. We describe such a method, based on the activation of T-lymphocytes in undiluted peripheral blood using phorbol myristate acetate (PMA). Following rapid hypotonic lysis and formaldehyde fixation, activation of the MAP kinase pathway can then be demonstrated using phospho-specific antibodies that recognize the activated mediators MEK or ERK, followed by surface labeling with anti-CD3 to identify T-lymphocytes. This method was used to investigate the effects of a MEK inhibitor, U0126, and a new raf kinase inhibitor BAY 37-9751 in blood samples from normal donors. Dose-dependent inhibition of pERK activation was demonstrated for both agents. Furthermore, differential effects on pMEK activation allowed the molecular targets of the two inhibitors to be distinguished. In addition to monitoring drug effects in patients during treatment with inhibitors of the MAP kinase pathway, the general methodology described in this paper has the potential for wide application to the study of signal transduction at the single cell level using flow cytometry.

Effect of knowledge of chronologic age on the variability of pediatric bone age determined using the Greulich and Pyle standards

OBJECTIVE

The purpose of this study was to investigate the impact of knowing chronologic age on the variability of pediatric bone age determination using the method of Greulich and Pyle.

MATERIALS AND METHODS

Radiographs of the left hand of 107 patients were interpreted by four radiologists on two separate occasions, once with and once without knowledge of the patient's chronologic age at time of interpretation. Twenty-five radiographs were randomly selected and reevaluated twice by each radiologist. Interobserver and intraobserver variability were calculated and compared for the two conditions. The distribution of studies with normal and abnormal findings was then compared across knowledge conditions for all observers and by individual observer, using two standard deviations above and below chronologic age as the range of "normal".

RESULTS

When the chronologic age was known, the interobserver reliability coefficient for knowledge of chronologic age was 0.954 and when not known, 0.952. The intraobserver reliability coefficients when chronologic age was known ranged from 0.944 to 0.967, and when not known from 0.938 to 0.980. Observers interpreted 58% (248/428) of the radiographs as having normal findings when chronologic age was known and 48% (205/428) when chronologic age was not known.

CONCLUSION

Knowing chronologic age before assessing bone age radiographs does not affect the reproducibility of assessment. However, observers are more likely to interpret the radiograph as showing normal findings when chronologic age is known than if the interpretation is performed with the observer unaware of chronologic age.

Identification and regulation of human PDE5A gene promoter

PDE5A gene encodes type 5 phosphodiesterase (PDE5), the principal cGMP-catalyzing enzyme in the penis and the primary target of sildenafil (Viagra). We have isolated a 3.7-kb DNA fragment that contains the human PDE5A gene promoter. The DNA fragment contains a sequence of 234 nucleotides at its 3' end that corresponds to most of the untranslated region of the PDE5A1 mRNA. The remaining 3.5-kb upstream flanking sequence contains no apparent TATA box but has several sequences that resemble binding sequences for transcription factors such as androgen receptor (AR), AP1, AP2, AP4, Sp1, MyoD, Myc, and CArG. In search of promoter activities, we used a luciferase reporter system to examine 10 DNA fragments that cover various regions of the 3.7-kb fragment. We found that a full basal promoter activity was confined to a 139-bp region that includes 78 bp of the PDE5A1-specific first exon. A lesser basal promoter activity was still detectable in a 94-bp fragment that contains the same 78-bp PDE5A1-specific exon plus 16 bp of upstream sequence. Either the 139-bp or the 94-bp promoter fragment responded minimally to cAMP or cGMP (2 mM) stimulation. Longer fragments that contain either a 308-bp 5' extension (from the 138-bp fragment) or a 156-bp 3' extension (all exon sequence) responded at higher levels to cAMP and cGMP stimulation. The 5' and 3' extensions cooperated with each other to provide the highest level of responses to cAMP and cGMP stimulation. DNase I footprint analysis identified four AP2- and two Sp1-binding sites in the 5' extension and four Sp1-binding sites in the 3' extensions. Cyclic AMP and cGMP had similar stimulatory effects on the PDE5A promoter.

Regulation of human PDE5A2 intronic promoter by cAMP and cGMP: identification of a critical Sp1-binding site

PDE5A gene encodes type 5 phosphodiesterase (PDE5), the principal cGMP-catalyzing enzyme in the penis and the primary target of sildenafil (Viagra). We have previously reported the isolation of three alternatively spliced PDE5A isoforms in humans. We also reported the identification of three corresponding alternative first exons and an intronic promoter in the human PDE5A gene. The intronic promoter is situated upstream from the PDE5A2-specific first exon but downstream from the PDE5A1- and A3-specific first exons. In the current study we showed that the intronic promoter could be upregulated by either cAMP or cGMP. In order to identify possible regulatory elements in the promoter, we created deletion and base-substitution mutants targeting one AP2- and four Sp1-binding sequences. Loss of function of these mutants to bind to the respective transcription factors was verified by DNase I footprint analysis, and changes in promoter function were analyzed with a luciferase reporter system. Mutation of the AP2-binding sequence and deletion of the 3'-most Sp1-binding site (within the exon) had little effects on the basal or the cyclic nucleotide-inducible promoter functions. Mutation of the 5'-most Sp1-binding site had much more severe effects on the basal and the cyclic nucleotide-inducible promoter functions. Mutation of a neighboring site that contains two overlapping Sp1-binding sequences completely nullified the basal and cyclic nucleotide-inducible promoter activities. Thus, the PDE5A2 intronic promoter depends on the overlapping Sp1-binding site for basal and cyclic nucleotide-inducible functions.

Direct evidence for Mendelian inheritance of the variations in the ribosomal protein gene introns in yellowfin tuna (Thunnus albacares)

Restriction fragment length polymorphism found in the S7 ribosomal protein gene introns of yellowfin tuna (Thunnus albacares) was compared between a single pair of parents and their offspring. The sizes of the first intron ( RP1) and second intron ( RP2) amplified by polymerase chain reaction were 810 bp and 1400 bp, respectively. The dam and sire had different restriction types from one another in HhaI and RsaI digestions for RP1 and in DdeI, HhaI, and ScrFI digestions for RP2. Putative genotypes in both introns of 64 larvae were found to be segregated in Mendelian proportions. Genotype distributions in a wild yellowfin tuna sample ( n = 34) were in Hardy-Weinberg proportions, and observed heterozygosity ranged from 0.149 to 0.388. This study presents novel Mendelian markers, which are feasible for tuna population genetic study and pedigree analysis.

Factors associated with non-urgent utilization of Accident and Emergency services: a case-control study in Hong Kong

Accident and Emergency Departments (A&E) have been a popular source of primary care, and studies have shown that up to two thirds of patients attending A&E have problems that could be managed by general practitioners (GPs). Although many studies have found that patients of lower socio-economic class with less social support have a higher utilization rate of A&E, some recent studies have revealed contrary evidence. In this study 2410 patients were randomly selected from four A&E at different times. The gold standard in differentiating true emergency cases and GP cases was based on a retrospective record review conducted independently by a panel of emergency physicians. Two emergency physicians reviewed each case independently, and if their independent ratings were in agreement, this became the gold standard. Patients classified as GP cases were given a telephone interview, and a sample was selected and matched with cases from general out patient clinics (GOPC) in the public sector by morbidity. Reasons for not attending a private GP included closure of clinic, deterioration of symptoms, GPs' inability to diagnose properly, and patients' wish to continue medical treatment in the same hospital. Reasons why non-urgent patients did not choose to attend the nearby public GOPC included affordability, closure of the GOPC, patients' wish to continue treatment at the same hospital, GOPC too far away, no improvement shown after visits to GOPC doctors, and GOPC doctors' inability to make proper diagnoses. The reasons for high level of utilization of A&E services are complex and reflect problems of delivery of GP services. There is an urgent need for GPs to set up a network system to provide out of hours services, and also for a better interfacing between primary and secondary care, and between public and private sectors, so that patients can be referred back to GPs. Interim clinical services provided to those non-urgent cases by nursing practitioners or by GPs working in A&E could also facilitate discharge of patients to primary care facilities.

Inhibition of phosphatidylinositide 3-kinase enhances gemcitabine-induced apoptosis in human pancreatic cancer cells

Human pancreatic adenocarcinoma cell lines PK1 and PK8 are resistant to the clinically relevant chemotherapy agent gemcitabine. Cell cycle analysis demonstrated an accumulation of cells in the early S phase during treatment with 20 microM gemcitabine, consistent with its mode of action as a DNA chain terminator. However, apoptosis was evident in only a small percentage of cells. Similar to pancreatic cancers in the clinic, PK1 and PK8 cells carry constitutively active Ki-Ras and overexpress multiple receptor tyrosine kinases. Both genetic abnormalities may potentially up-regulate the activity of the phosphatidylinositide 3-kinase (P13K)-protein kinase B (PKB)/Akt cell survival pathway. The current study examined the relevance of this pathway in the modulation of drug resistance in PK1 and PK8 cells. After exposure to 20 microM gemcitabine for 48 h and in the continuous presence of the drug, treatment with the P13K inhibitors wortmannin (50-200 nM) and LY294002 (15-120 microM) for 4 h substantially enhanced apoptosis in a concentration-dependent manner as compared with treatment with gemcitabine alone, as determined by the loss of mitochondrial membrane potential and the increase in propidium iodide uptake using flow cytometry. Furthermore, Western blotting showed that the reduction of phosphorylated PKB/Akt levels correlated with the enhancement of gemcitabine-induced apoptosis, suggesting that the PI3K-PKB/Akt pathway plays a significant role in mediating drug resistance in human pancreatic cancer cells. PI3K inhibitors may have therapeutic potential when combined with gemcitabine in the treatment of pancreatic cancers.

Discrimination between Atlantic and Pacific Subspecies of Northern Bluefin Tuna (Thunnus thynnus) by Magnetic-Capture Hybridization Using Bacterial Magnetic Particles

The previously developed magnetic-capture hybridization technique employing bacterial magnetic particles was applied to discriminate between Atlantic and Pacific subspecies of the northern bluefin tuna (Thunnus thynnus) using specific DNA sequences. Nucleotide sequences of a 925-bp fragment (ATCO) flanking the mitochondrial ATPase and cytochrome oxidase subunit III genes in these two subspecies were compared. Two regions having single-nucleotide and three-nucleotide differences between the subspecies were adopted to design DNA probes (NR1, 21-mer; NR2, 29-mer), and two internal primer sets were designed to amplify DNA fragments containing these regions. The DNA probes were immobilized on bacterial magnetic particles via streptavidin-biotin conjugation and subjected to magnetic-capture hybridization with the digoxigenin-labeled fragments amplified using the internal primers. The luminescence intensities of DNA on bacterial magnetic particles obtained by hybridization between the probes and the complementary fragments were higher than those obtained by hybridization with noncomplementary fragments. These data suggest that this system employing DNA on bacterial magnetic particles may be useful for discrimination of these two subspecies by recognizing a single-nucleotide difference.

Measuring the inappropriate utilization of accident and emergency services?

Accident and Emergency (A&E) departments are increasingly popular venues for primary care, causing a serious threat to healthcare quality. This paper reports the development of a comprehensive research method for identifying primary care patients attending A&E. Patients were randomly selected from the four A&E departments across different time periods and different regions in Hong Kong. The definition of GP cases was based on a retrospective record review conducted by a panel of emergency physicians using the standard laid down by the Hong Kong College of Family Physicians. The patients sampled were similar in sex and age distribution to A&E attendees for the whole territory. The level of GP cases was found to be 57 per cent, with a significantly higher proportion of patients in the younger age group. The high level of use reflects the lack of a well co-ordinated development of primary care services and interfacing with secondary care.

Genetic divergence between Atlantic and Indo-Pacific stocks of bigeye tuna (Thunnus obesus) and admixture around South Africa

Two mitochondrial DNA segments of the bigeye tuna (Thunnus obesus) were amplified by polymerase chain reaction (PCR), and restriction fragment length polymorphism (RFLP) analyses of these segments were used for the genetic stock study. The variation in a segment flanking the ATPase and COIII genes was low; only two genotypes (alpha and beta) were detected by RsaI digestion. Yet a large difference in the genotype distribution was observed between ocean basin samples. The alpha type predominated in four Atlantic samples, where 178 of 244 individuals were the alpha type. In contrast, only one of 195 individuals collected in the Indo-Pacific was the alpha type? The frequency of the alpha type varied considerably from 0 to 80% among seven samples collected off the Cape of Good Hope. The variation found in the other segment, containing the D-loop region, was much higher; two endonucleases (DpnII and RsaI) detected five genotypes each and 15 composite genotypes. A highly significant difference in genotype frequencies was observed between the Atlantic and Indo-Pacific samples, but no heterogeneity was observed among the four Atlantic or among four Indo-Pacific samples. These results clearly indicate that not only gene flow, but also fish migration, between the Atlantic and Indian Oceans are severely restricted, and that fishes from these distinct stocks are intermingling around South Africa. The simple and diagnostic genetic marker found in this study can be used to estimate mixing ratios between Atlantic and Indian stocks around South Africa.

A comparison in individual murine tumors of techniques for measuring oxygen levels

PURPOSE

To investigate the relationship between different techniques for measuring oxygen levels in a murine tumor model.

METHODS AND MATERIALS

Using the murine fibrosarcoma line KHT-C, five techniques of measuring oxygen levels-the Eppendorf pO2 Histograph, EF5 binding, the comet assay, a paired survival assay, and an in vivo growth delay assay-were assessed. In these experiments, three or more techniques were applied in different combinations to measure the oxygen levels in individual tumors.

RESULTS

Statistically significant correlations were observed between the hypoxic proportions calculated from the paired survival assay with those from EF5 binding. The comet assay was found to have a statistically significant correlation with the paired survival analysis and the growth delay analysis. No statistically significant correlation was found between the Eppendorf pO2 Histograph measurements and those from the other techniques, although there were weak correlations with the paired survival assay and EF5 binding. For technical reasons, a comparison was not made between EF5 binding and the growth delay assay.

CONCLUSIONS

The correlations found between EF5 binding and the comet assay with the radiobiological assays suggest that these techniques have potential for predicting outcome following radiation treatment. The lack of correlation seen between the pO2 Histograph data and the radiobiological assays is in contrast to results from early clinical trials.

Imaging features of avulsion injuries

Avulsion injuries are common among participants in organized sports, especially among adolescent participants. Imaging features of both acute and chronic avulsion injuries of the pelvis, knee, ankle and foot, shoulder, and elbow were evaluated to help distinguish these injuries from more serious disease processes such as neoplasm and infection. At radiography, acute injuries (ie, those resulting from extreme, unbalanced, often eccentric muscular contractions) may be associated with avulsed bone fragments, whereas subacute injuries have an aggressive appearance that may include areas of mixed lysis and sclerosis. Chronic injuries (ie, those resulting from repetitive microtrauma or overuse) or old inactive injuries may be associated with a protuberant mass of bone and may bear a striking resemblance to a neoplastic or infectious process. Although not usually required, computed tomography is helpful in the diagnosis if radiographic findings are equivocal or if the injury is not in the acute phase. MR imaging is best suited for the evaluation of injuries to muscles, tendons, and ligaments. Recognition of characteristic imaging features and familiarity with musculotendinous anatomy will aid in accurate diagnosis of avulsion injuries.

Induction of microtubule-associated protein 1B expression in Schwann cells during nerve regeneration

Microtubule-associated protein 1B (MAP1B) is expressed at high levels during development of the nervous system and is localized primarily in neurons while specific phosphorylated isoforms of MAP1B are localized exclusively in growing axons. The levels of MAP1B are down regulated in most regions of the adult CNS, but remain high in neurons and axons of the PNS. This study demonstrates that the expression of MAP1B is induced in adult Schwann cells following sciatic nerve lesion and regeneration. High levels of both mRNA and the MAP1B protein were detected in Schwann cells associated with the axotomized distal stump. Expression of MAP1B was also observed in cultured primary Schwann cells from neonatal rats. The properties of the MAP1B protein in cultured Schwann cells were further characterized by Western blot analysis using specific antibodies that recognize the N-terminal, middle and C-terminal domains of MAP1B. All of these antibodies detected a protein of 320-340 kDa demonstrating that MAP1B expressed by Schwann cells is very similar, or identical, to MAP1B expressed by neurons. The phosphorylation of MAP1B in Schwann cells was also studied using monoclonal antibodies (mAb) that recognize specific phosphorylation epitopes. The results indicated that the expression of MAP1B in Schwann cells exhibited a differential phosphorylation state that was recognized by mAb 1B6 but not by other mAbs, including 1B-P, 150 and RT97, that recognize phosphorylated MAP1B in growing axons. We therefore conclude that MAP1B is expressed in Schwann cells during both development and axonal regeneration, suggesting that the developmental pattern of MAP1B in these cells is recapitulated in adult Schwann cells during the early stages of regeneration and remyelination of injured peripheral axons. The presence of MAP1B in Schwann cells may support morphological changes of these cells, particularly the formation of processes prior to their differentiation into myelin forming Schwann cells.

Total skin electron beam therapy with or without adjuvant topical nitrogen mustard or nitrogen mustard alone as initial treatment of T2 and T3 mycosis fungoides

PURPOSE

To compare the efficacy of total skin electron beam therapy (TSEBT) with or without adjuvant topical nitrogen mustard (+/- HN2) with topical nitrogen mustard (HN2) alone as initial management of T2 and T3 mycosis fungoides (MF).

METHODS AND MATERIALS

A retrospective analysis of 148 patients presenting to Stanford from January, 1970 through January, 1995 within 4 months of pathologic diagnosis of MF. Fifty-five patients with T2 and 27 with T3 disease received TSEBT +/- HN2. Fifty-four patients with T2 and 12 with T3 disease received HN2 alone. Boosts with radiotherapy were usually administered to cutaneous tumors of patients with T3 disease.

RESULTS

TSEBT +/- HN2 yielded significantly higher complete response (CR) rates than did HN2 alone in patients with T2 and T3 disease (76% vs 39%, p = 0.03 for T2, and 44% vs 8%, p < 0.05 for T3, respectively). In T2 disease, treatment with adjuvant HN2 was associated with a longer freedom from relapse following TSEBT when compared to observation following a CR to TSEBT (p = 0.068). However, no significant differences in survival were observed for different management programs for T2 or T3 disease. In T2 disease, both TSEBT and HN2 were as effective as salvage therapy as when utilized as initial therapy. However, salvage therapy in T3 disease was rarely effective. Limited tumor involvement in T3 disease did not correlate with improved survival compared to more generalized tumorous disease. MF contributed to 27% and 68% of deaths in patients with T2 and T3 disease, respectively.

CONCLUSION

Because of high response rates, management of significantly symptomatic or extensive T2 MF should include TSEBT, and adjuvant HN2 should be administered after a CR to TSEBT. Patients with T2 disease who fail TSEBT or HN2 can be salvaged with the other modality. TSEBT is also an effective treatment for T3 disease. The small subset of patients with limited T3 disease may also be treated with HN2 and local radiotherapy to the tumors. Further investigations are necessary to improve the overall outcome for T3 mycosis fungoides.