Prognostic value of magnetic resonance imaging in the management of fistula-in-ano

PURPOSE

Magnetic resonance imaging of fistula-in-ano has been shown to predict surgical anatomy accurately and identify complex features. In addition, fistula complexity has been correlated with poor outcome after surgical intervention. We investigated whether preoperative magnetic resonance imaging could predict clinical outcome after surgery for fistulous disease better than clinical examination under anesthetic.

METHODS

Seventy patients with clinically suspected fistula-in-ano underwent preoperative dynamic contrast-enhanced magnetic resonance imaging before surgical exploration. Outcome was assessed at a minimum of one year after surgical exploration and correlated in a blinded fashion with the surgical and magnetic resonance grading of the severity of the fistulous disease.

RESULTS

Of 70 patients, 12 were not operated on and 6 were lost to follow-up, making 52 patients eligible for analysis. Assessment by dynamic contrast-enhanced magnetic resonance imaging more accurately predicted outcome than the findings at initial surgical exploration. Dynamic contrast-enhanced magnetic resonance imaging had a sensitivity of 81 percent, specificity of 73 percent, and positive predictive value of 75 percent; surgery had a sensitivity of 77 percent, specificity of 46 percent, and positive predictive value of 59 percent. Surgical assessment of apparent disease severity bore no relation to final outcome. Dynamic contrast-enhanced magnetic resonance imaging could accurately predict whether patients were likely to have a satisfactory or unsatisfactory outcome after surgery.

CONCLUSION

Dynamic contrast-enhanced magnetic resonance imaging better predicts clinical outcome of patients with fistula-in-ano than initial surgical exploration.

MRI of liver: a comparison of CNR enhancement using high dose and low dose ferumoxide infusion in patients with colorectal liver metastases

The purpose of this study was to compare the effects of high dose (HD) and low dose (LD) ferumoxides infusions on lesion-to-liver contrast-to-noise ratio (CNR) using four different T(2)-weighted MR sequences. Seventy-three patients with known colorectal liver metastases underwent T(2)-weighted fast spin echo (FSE) imaging before and after ferumoxides. After ferumoxides, T(2)-weighted dual echo (DE) and T(2)-weighted GRE FLASH images were also obtained. To evaluate the relationship between TE length and lesion-to-liver CNR, the same FLASH sequence was repeated in 18 LD patients after lengthening the TE. Ferumoxides was administered at a dose of 15 micromol/kg (HD) and 7.5 micromol/kg (LD) in 45 and 28 patients, respectively. The effects of HD and LD ferumoxides infusions were measured as the percentage signal intensity change (PSIC) in the liver and lesions, lesion-to-liver CNR and the change in lesion-to-liver CNR (DeltaCNR). In both LD and HD groups, all CNR values obtained after SPIO were significantly greater than those observed with unenhanced FSE (p < 0.01). There was no significant difference between the mean CNR values obtained with either dose for any sequence. With the FLASH sequence, CNR increased progressively with longer TE. At the longest TE of 26 ms, mean CNR was higher than that recorded with any of the other sequences. Although mean liver PSIC was significantly greater in the HD group than in the LD group (p < 0.01) because the mean lesion PSIC was also greater in the HD group, the mean DeltaCNR after ferumoxides was not significantly different in the two groups. LD SPIO enhanced MR significantly increases lesion-to-liver CNR compared with unenhanced images. At 1. 0 T, HD and LD ferumoxides infusions produce comparable lesion-to-liver CNR. Our results suggest that at 1.0 T ferumoxides may be administered at a dose of 7.5 micromol/kg without loss of image quality.

Maximizing response rates to a survey of dentists: a randomized trial

Dentists currently practising within the Central Sydney Area were surveyed (n = 179). A randomized controlled trial was conducted to evaluate the effect of an advance telephone prompt (intervention group) compared with an advance letter prompt only (control group) in maximizing the response rate to a self-administered questionnaire. While the overall response rate was 83 per cent, the final response rate (89 per cent) from dentists in the intervention group was significantly higher than that from dentists in the control group (78 per cent) (chi 2 = 4.14, df = 1, p = 0.04). Advance telephone prompts are effective in maximizing the response rates from dentists and are recommended in future surveys of this professional group.

The impact on retention of expansion of an Australian public methadone program

Although rapid expansion of methadone programs has occurred in many countries, there are few studies of the impact on treatment success. The one public methadone maintenance program in Canberra was expanded from 85 places in 1991 to 350 places in late 1992. While this responded to a real need, it also led to a temporary increase in drop-outs. Retention was considerably improved in 1996 when clients began to be transferred from the public program to fee-for-service primary health care, but the improvement was also not sustained. In recent years, one-quarter to one-half of clients dropped out before stabilization. Multiple entries into treatment were common and overall retention was not affected by previous treatment episodes or length of time between episodes. Methadone programs should monitor retention as part of on-going evaluation and improvement of treatment policy.

Intrathecal baclofen for management of spastic cerebral palsy: multicenter trial

Intrathecal baclofen infusion has demonstrated effectiveness in decreasing spasticity of spinal origin. Oral antispasticity medication is minimally effective or not well tolerated in cerebral palsy. This study assessed the effectiveness of intrathecal baclofen in reducing spasticity in cerebral palsy. Candidates were screened by randomized, double-blind, intrathecal injections of baclofen and placebo. Responders were defined as those who experienced an average reduction of 1.0 in the lower extremities on the Ashworth Scale for spasticity. Responders received intrathecal baclofen via the SynchroMed System and were followed for up to 43 months. Fifty-one patients completed screening and 44 entered open-label trials. Lower-extremity spasticity decreased from an average baseline score of 3.64 to 1.90 at 39 months. A decrease in upper extremity spasticity was evidenced over the same study period. Forty-two patients reported adverse events. Most common reports were hypotonia, seizures (no new onset), somnolence, and nausea or vomiting. Fifty-nine percent of the patients experienced procedural or system-related events. Spasticity in patients with cerebral palsy can be treated effectively by continuous intrathecal baclofen. Adverse events, although common, were manageable.

Hepatic lesion detection after superparamagnetic iron oxide enhancement: comparison of five T2-weighted sequences at 1.0 T by using alternative-free response receiver operating characteristic analysis

PURPOSE

To compare the accuracy of five T2-weighted sequences in the detection of liver lesion at magnetic resonance (MR) imaging after superparamagnetic iron oxide (SPIO) enhancement.

MATERIALS AND METHODS

Forty-nine candidates for hepatic resection with known coloretal metastases were examined. Before SPIO enhancement, fast spin-echo (SE) images were obtained. After enhancement, the same fast SE sequence and long; TR/short TE, short TE, long TR/TE, and T2-weighted fast low-angle shot (FLASH) sequences were used. All images were viewed independently by four observers who were blinded to the results of the other imaging sequences, the results of the other observers, and the findings at surgery and histopathologic examination. Four weeks after the initial reading, the combined long TR/short TE and long TR/TE dual-echo images were also viewed as an additional set. The alternative free response receiver operating characteristic (ROC) method was used to analyze the results, which were correlated with findings at surgery, intraoperative ultrasonography, and histopathologic examination.

RESULTS

Irrespective of lesion size, the accuracy of all sequences after enhancement was significantly greater than that of the nonenhanced fast SE sequence (P < .01). Dual-echo and FLASH sequences were significantly more accurate than the enhanced fast SE sequence (P < .03 or P < .02, respectively). For all lesions, lesions smaller than 1 cm, and lesions 1 cm or larger, mean accuracies were as follows: dual-echo, 0.75, 0.54, and 0.93; FLASH, 0.75, 0.54, and 0.95; and enhanced fast SE, 0.72, 0.49, and 0.92.

CONCLUSION

At 1.0 T, dual-echo and FLASH sequences are the most accurate pulse sequences after SPIO enhancement.

Negative regulation of macrophage activation in response to IFN-gamma and lipopolysaccharide by the STK/RON receptor tyrosine kinase

IFN-gamma primes macrophages for antimicrobial activity, increased killing of intracellular pathogens, and Ag processing and presentation to lymphocytes by cooperating with a second signal (provided by LPS or endogenous TNF-alpha) to promote increased proinflammatory cytokine production, NO production, and MHC class II expression. Macrophage-stimulating protein (MSP) suppresses NO production by activated peritoneal macrophages in vitro. Furthermore, targeted deletion of the receptor for MSP, stem cell-derived tyrosine kinase receptor (STK/RON), resulted in increased production of NO by activated macrophages both in vitro and in vivo. Here we demonstrate that expression of STK in RAW264.7 cells resulted in suppression of NO production following IFN-gamma+/- LPS stimulation in the presence of MSP, reflecting a decrease in the levels of inducible NO synthase (iNOS) mRNA and protein, which was confirmed by decreased trans-activation of an iNOS reporter. The iNOS expression is regulated by the coordinate activity of the inducible transcription factors STAT-1, IFN response factor-1, and NF-kappaB. The presence of the STK receptor did not significantly alter the expression of the IFN-gamma receptor, STAT1 phosphorylation, or the up-regulation of IFN response factor-1 expression following IFN-gamma stimulation. However, nuclear translocation of NF-kappaB following stimulation of RAW cells with IFN-gamma and LPS was reduced in the presence of the MSP/STK signaling pathway. These results suggest that the negative regulation of macrophage responses by MSP/STK occurs at least in part via inhibition of costimulatory signals, resulting in NF-kappaB activation, that cooperate with IFN-gamma to promote activation.

Combined vaccination of Haemophilus influenzae type b conjugate and diphtheria-tetanus-pertussis containing acellular pertussis

After the introduction of effective Haemophilus influenzae type b (Hib) conjugate vaccines, clinical practice has driven the development of combination vaccines comprising Hib conjugates with the infant diphtheria-tetanus-pertussis (DTP) vaccines. However, when such combinations contain an acellular pertussis component (Pa), the antibody response to Hib is lower than that with separate injections and doubts have been raised about their efficacy. We believe that such concerns are unwarranted, since the serological correlates of efficacy previously applied for Hib polysaccharide vaccines seem inappropriate for Hib conjugates. Furthermore, our own studies have shown that the lower antibody responses are not associated with impaired function of the antibodies induced, nor, and possibly more importantly, with the induction of immune memory against Hib. Therefore, with the proviso that careful clinical surveillance of Hib disease is maintained, we encourage the introduction of DTPa-Hib combinations to facilitate the inclusion of Hib into the already crowded childhood immunisation schedule.

Screening for malnutrition

This article recommends that screening for malnutrition is used in both primary care and hospital settings. The authors also outline how nurses are ideally placed to screen patients for evidence of malnutrition and to offer first line nutritional advice and care.

Implementation of nationally developed guidelines in cardiology: a survey of NSW cardiologists and cardiothoracic surgeons

BACKGROUND

In July 1996, the National Health and Medical Research Council (NHMRC) published clinical practice guidelines for 'The Procedural and Surgical Management of Coronary Heart Disease'. Despite increasing interest in dissemination and implementation of guidelines, initial reactions to these specific Guidelines and factors critical to their successful implementation had not been determined until our study.

AIMS

To determine views of New South Wales (NSW) clinicians towards these NHMRC Guidelines; to identify perceptions about local relevance, usefulness and likely impact and to elicit preferred implementation strategies.

METHODS

A postal survey in November 1997 of all cardiologists and cardiothoracic surgeons in NSW.

RESULTS

One hundred and ten of 174 clinicians returned the questionnaire (63% response rate). Forty-eight per cent indicated that they were aware of the Guidelines before receiving a copy with the questionnaire while 26% had commented on the draft version of the Guidelines when distributed in November 1995. More than half of respondents 'agreed' or 'strongly agreed' with six of nine statements about potential strengths of the Guidelines. While at least 25% 'disagreed' or 'strongly disagreed' on 11 out of the 13 statements about potential criticisms of the Guidelines, more than half agreed or 'strongly' agreed that the Guidelines did not tell them 'anything they didn't already know'. Fifty-two per cent 'agreed' or 'strongly agreed' that guidelines will be misinterpreted by lawyers. At least 30% rated nine out of 11 implementation strategies as important. Local audits of care and regular feedback, reports from colleagues at conferences and hospital workshops outranked other implementation strategies in encouraging uptake of the Guidelines.

CONCLUSIONS

Clinicians in NSW have generally positive views about the Guidelines, however, medicolegal concerns are apparent. To strengthen evidence-based decision-making as exemplified by the Guidelines, audits, presentations by opinion leaders and hospital-based workshops are recommended.

Heterotopic endochondrial ossification with mixed tumor formation in C3(1)/Tag transgenic mice is associated with elevated TGF-beta1 and BMP-2 expression

Transgenic mice which express the simian virus 40 large T-antigen (Tag) under the regulatory control of the hormone responsive rat C3(1) gene develop unusual lesions of heterotopic bone growth associated with mixed tumor formation arising from eccrine sweat glands found only in the foot pads of mice, ischiocavernosus muscle adjacent to bulbourethral glands and occasionally the salivary and mammary glands. These lesions are very similar to mixed tumors arising in several types of human cancers. Based upon electron microscopic examination and immunocytochemical analyses of cellular differentiation markers, the mixed proliferative lesions in this transgenic mouse model begin with the Tag-induced proliferation of epithelial and myoepithelial cells. The proliferation of these two types of cells results in hyperplasia and adenomatous transformation of the epithelial component, whereas the proliferating myoepithelial cells undergo metaplasia to form chondrocytes which deposit extracellular matrix, including collagen fibers. Cartilage develops focally between areas of epithelial proliferation and subsequently ossifies through a process of endochondrial bone formation. The metaplasia of myoepithelial cells to chondrocytes appears to require the inductive interaction of factors produced by the closely associated proliferating epithelial cells, including members of the TGF-beta superfamily. We demonstrate that TGF-beta1 protein accumulates in the extracellular matrix of the lesions, whereas RNA in situ hybridization reveals that BMP-2, another strong inducer of heterotopic bone formation, is overexpressed by the proliferating epithelial cells during the development of ectopic bone. The formation of sarcomatous tumors within the mixed tumors appears to be androgen-dependent and more frequent in mice lacking a normal allele of p53. This process of cartilage and bone induction may mimic epithelial-mesenchymal interactions which occur during embryonic bone formation. These transgenic mice may provide new insights into the processes of ectopic endochondrial bone formation associated with mixed tumor formation and serve as a useful model for human heterotopic bone disease.

Dynamic contrast-enhanced MR imaging and dual-phase helical CT in the preoperative assessment of suspected pancreatic cancer: a comparative study with receiver operating characteristic analysis

OBJECTIVE

The purpose of this study was to compare dynamic contrast-enhanced MR imaging and dual-phase helical CT in the preoperative assessment of patients with suspected pancreatic carcinoma.

SUBJECTS AND METHODS

Thirty-three consecutive surgical candidates (20 men, 13 women; 39-81 years old) were included. MR imaging comprised fast spin-echo (TR/TE 4000/91), fat-suppressed T1-weighted spin-echo (500/15), and T1-weighted breath-hold gradient-echo fast low-angle shot (100/4; flip angle, 80 degrees) images before and after the administration of gadopentetate dimeglumine. Helical CT used 5-mm collimation with a pitch of 1:1.5-1.7; images were obtained 20 and 65-70 sec after injection of 150 ml of contrast material. Two pairs of interpreters who were unaware of the results of the other imaging method independently scored each examination for the presence of a lesion and for surgical resectability using a five-point scale. Results were correlated with surgery (n = 25) or consensus review (n = 8). Receiver operating characteristic methodology was used to analyze the results for resectability, and positive predictive values were calculated.

RESULTS

Both MR imaging and helical CT revealed 29 of 31 lesions. In determining lesion resectability, the mean areas under the receiver operating characteristic curves were 0.96 and 0.81 (p = .01) and the positive predictive values were 86.5% and 76% (p = .02) for MR imaging and helical CT, respectively.

CONCLUSION

MR imaging and helical CT performed equally well in lesion detection. MR imaging was significantly better in the assessment of resectability of pancreatic tumors.

Uteroglobin is essential in preventing immunoglobulin A nephropathy in mice

The molecular mechanism(s) of immunoglobulin A (IgA) nephropathy, the most common primary renal glomerular disease worldwide, is unknown. Its pathologic features include hematuria, high levels of circulating IgA-fibronectin (Fn) complexes, and glomerular deposition of IgA, complement C3, Fn and collagen. We report here that two independent mouse models (gene knockout and antisense transgenic), both manifesting deficiency of an anti-inflammatory protein, uteroglobin (UG), develop almost all of the pathologic features of human IgA nephropathy. We further demonstrate that Fn-UG heteromerization, reported to prevent abnormal glomerular deposition of Fn and collagen, also abrogates both the formation of IgA-Fn complexes and their binding to glomerular cells. Moreover, UG prevents glomerular accumulation of exogenous IgA in UG-null mice. These results define an essential role for UG in preventing mouse IgA nephropathy and warrant further studies to determine if a similar mechanism(s) underlies the human disease.

Population-based mammographic screening: does 'informed choice' require any less than full disclosure to individuals of benefits, harms, limitations and consequences?

Mammographic screening is a public health intervention with benefits, harms and consequences. Assuming technical excellence and at least 70% participation, mammographic screening of women aged 50 years or over will reduce breast cancer mortality by 24%. Before the introduction of mammographic screening in Australia, the mortality rate from breast cancer for women in the target age group was 69.0 per 100,000. On the basis of this relative risk reduction, breast cancer mortality would be reduced to 46 per 100,000. However, for every breast cancer death averted, 10 additional cases of breast cancer will be diagnosed. As it is unknowable who will benefit from mammographic screening, it is unethical to claim that any given individual has been 'saved' through participation, especially in the absence of evidence that all-cause mortality will change. As women misunderstand their risks of breast cancer and the benefits and limitations of mammographic screening, public education is needed. As an individual's choice about screening is affected by the way benefits are framed, our public messages must be carefully scrutinised. It is impossible otherwise to assert that women are making an 'informed choice'. The decision of women who decline to participate must be respected. Public health expertise is crucial to ensure the rhetoric of 'informed choice' in cancer screening is realised.

MR imaging of the liver and spleen: a comparison of the effects on signal intensity of two superparamagnetic iron oxide agents

We compared the effects of two superparamagnetic iron oxide (SPIO) contrast agents, ferumoxides and SHU-555A, in MR imaging of the liver and spleen. Thirty-six patients with known malignant lesions of the liver underwent T2W turbo spin-echo (TSE) and T1WGRE FLASH opposed-phase imaging before and after SPIO injection on a 1.0 T MR system. Post-ferumoxides images were obtained in 18 patients 90 min after infusion of 15 micrommol Fe/kg of the agent. In 18 other patients SHU-555A was administered as a rapid bolus at a dose of 7.0-12.9 micrommol Fe/kg. T1WGRE FLASH images were obtained immediately, 30 s and 480 s and T2WTSE images 10 min after injection. Signal intensity of the liver, spleen, and malignant liver lesions before and after SPIO was measured with operator-defined regions of interest. The effects of ferumoxides and SHU-555A were measured as the percentage signal intensity change (PSIC) and in the malignant liver lesions additionally as changes in lesion-to-liver contrast-to-noise ratio (deltaDCNR). On T2W TSE images, there was no significant difference between the two agents in signal loss of liver parenchyma (p > 0.05). The signal loss in the spleen produced by ferumoxides was greater than with SHU-555A (p < 0.05). Both SPIO agents produced a significant increase in the CNR of malignant liver lesions. Delta CNR was slightly greater with ferumoxides than with SHU-555A (p < 0.05). On T1WGRE FLASH images, a slight decrease of liver SI induced by both agents was found on late post-SPIO images. No significant difference of liver PSIC between the two SPIO agents was noted on T1W images. The SI of spleen was significantly increased with both agents on T1W images and no difference in PSIC of spleen was noted (p > 0.05). The T1 and T2 effects produced by ferumoxides and SHU-555A were comparable in the liver although ferumoxides produced a stronger T2 effect in the spleen.

Brain stem blood flow, pupillary response, and outcome in patients with severe head injuries

OBJECTIVE

Acute pupillary dilation in a head-injured patient is a neurological emergency. Pupil dilation is thought to be the result of uncal herniation causing mechanical compression of the IIIrd cranial nerve and subsequent brain stem compromise. However, not all patients with herniation have fixed and dilated pupils, and not all patients with nonreactive, enlarged pupils have uncal herniation. Therefore, we have tested an alternative hypothesis that a decrease in brain stem blood flow (BBF) is a more frequent cause of mydriasis and brain stem symptomatology after severe head injury. We determined the relation of BBF to outcome and pupillary response in patients with severe head injuries.

METHODS

One hundred sixty-two patients with a Glasgow Coma Scale score of 8 or less underwent stable xenon computed tomographic blood flow determination at the level of the superior colliculus, and this blood flow was correlated with pupillary features, intracranial pressure, computed tomographic scan pathology, and outcome.

RESULTS

A BBF of less than 40 ml/100 g/min was significantly associated with poor outcome (P < 0.009). In patients with bilaterally nonreactive pupils, the BBF was 30.5+/-16.8 ml/100 g/min, and in those with normally reactive pupils, the BBF was 43.8+/-18.7 ml/100 g/min (P < 0.001). Intracranial pressure and the presence of a brain stem lesion observed on the computed tomographic scan did not correlate with BBF, pupillary size, or reactivity. Unfavorable outcome at 12 months was directly related to age (P = 0.062) and inversely related to pupillary responsiveness (P = 0.0006), pupil size (P = 0.005), and BBF of less than 40 ml/100 g/min (P = 0.009).

CONCLUSION

These findings suggest that pupillary dilation is associated with decreased BBF and that ischemia, rather than mechanical compression of the IIIrd cranial nerve, is an important causal factor. More important, pupil dilation may be an indicator of ischemia of the brain stem. If cerebral blood flow and cerebral perfusion pressure can be rapidly restored in the patient with severe head injury who has dilated pupils, the prognosis may be good.

Target dyspnea ratings predict expected oxygen consumption as well as target heart rate values

A target heart rate (THR) is the traditional method to prescribe and monitor exercise training intensity in healthy individuals. However, patients with chronic obstructive pulmonary disease (COPD) are limited by ventilatory impairment and dyspnea rather than cardiovascular factors. An alternative approach is to use dyspnea ratings as a target for exercise training in patients with respiratory disease just as ratings of perceived exertion have been used in healthy individuals. The study was a randomized, parallel group trial comparing the ability of patients with COPD to accurately and reliably produce an exercise intensity using a target dyspnea rating (TDR) versus a THR. At Visit 1 patients performed an incremental exercise test on the cycle ergometer, and target values were calculated at approximately 75% of maximal oxygen consumption (V O2). At Visits 2 (3 to 5 d later) and 3 (2 wk later) each patient was instructed to produce a TDR or a THR for 10 min of submaximal exertion. Anthropometric characteristics, lung function, and exercise performance were similar for the 22 patients in each group at Visit 1. For the TDR group the dyspnea target was 2.5 +/- 1.5 at an expected V O2 of 0.88 +/- 0.28 L/min; for the THR group the heart rate (HR) target was 114 +/- 15 beats/min at an expected V O2 of 0.76 +/- 0.29 L/min (p = 0.18 for V O2 between groups). Compared with the expected V O2 from Visit 1, the individual percent differences in V O2 at Visit 2 were -3.9 +/- 18.1% (TDR) and -0.5 +/- 23.2% (THR) (p = 0.58); at Visit 3 the individual percent differences in V O2 were -2.3 +/- 17.0% (TDR) and 2.6 +/- 30.6% (THR) (p = 0.52). The number of patients < 10% and >/= 10% of the expected V O2 were similar for the two groups at Visits 2 (p = 0.38) and 3 (p = 0.27). There were no significant differences for V O2 values (absolute or individual percent) at Visits 2 and 3 for each group and between the groups (p = 0.79). In conclusion, patients with symptomatic COPD demonstrated a comparable ability to use dyspnea ratings and HR as a target to accurately and reliably produce an expected exercise intensity (approximately 75% of V O2max) for 10 min of submaximal exertion.