Necrotizing fasciitis of the lower limb: an outcome study of surgical treatment

Necrotizing fasciitis is a limb- and life-threatening rapidly spreading infection affecting the deep fascia with secondary necrosis of the subcutaneous tissue. It requires immediate medical attention and emergency surgery to prevent morbidity and death. This study was undertaken to determine its co-morbidity and risk factors affecting the outcome of its surgical treatment. This is a retrospective review of 36 cases of necrotizing fasciitis of the lower limb treated in our center between 1998 and 2002. Only 19% of the cases were correctly diagnosed upon admission and 48.6% were initially diagnosed as 'cellulitis'. Diabetes mellitus was the most common co-morbid. Pseudomonas, Staphylococcus, Streptococcus and Enterobactericae were the common pathogens isolated. Ten patients (27.8%) had major amputation as part of radical debridement. The overall mortality rate was 36% with laboratory parameters: high serum urea and creatinine, and low haemoglobin levels were predictors for higher mortality. Poor white cell response which is common in diabetic patients and a delay in surgical debridement were. notable attributes to a higher mortality. Necrotizing fasciitis is a serious infection associated with significant morbidity and mortality. A poor white blood cell response, high serum urea and creatinine, and low haemoglobin level were the predictors for mortality. Early diagnosis and prompt treatment are of paramount importance in the treatment of this infection.

In Vitro Evaluation of the Performance of Korean Pulsatile ECLS (T-PLS) Using Precise Quantification of Pressure-Flow Waveforms

The Twin-Pulse Life Support System (T-PLS) is a novel pulsatile extracorporeal life support system developed in Korea. It has been reported that the T-PLS achieves higher levels of tissue perfusion of the kidney during short-term extracorporeal circulation and provides more blood flow to coronary artery than nonpulsatile blood pumps. However, these results lack pulsatility quantifications and thus make it hard to analyze the effects of pulsatility upon hemodynamic performance. We have adopted the concepts of hemodynamic energy, energy equivalent pressure (EEP), and surplus hemodynamic energy (SHE) to evaluate pulsatility performance in the different circuit configurations of the T-PLS and a membrane oxygenator (MO) in vitro. In a mock system, three different circuits were constructed depending on the location of an MO: pump-MO-pump (serial), MO-pumps (parallel A), and pumps-MO (parallel B). In parallel A, a low-resistance MO was used to preserve the pulsatility from the pump. All circuits showed good pulsatility in terms of EEP (serial: 13.2% +/- 3.2%, parallel A: 10.0% +/- 1.6%, parallel B: 7.00% +/- 1.1%; change from aortic pressure to EEP; p < 0.003). The SHE levels were 17,404 +/- 3750 ergs/cm3, 13,170 +/- 1486 ergs/cm3, and 9192 +/- 1122 ergs/cm3 in each circuit setup (p < 0.001). Although EEP levels were somewhat lower, both parallel types provided higher pump output compared with the serial type (serial: 1.87 +/- 0.29 l/min, parallel A: 3.09 +/- 0.74 l/min, parallel B: 3.06 +/- 0.56 l/min; p < 0.003 except parallel A vs. parallel B, p = 0.90). Conclusively, the precise quantifications of pressure flow waveforms, EEP, and SHE are valuable tools for evaluating pulsatility of the mechanical circulatory devices, and are expected to be used as additional performance indexes of a blood pump. The pulsatility performances are different according to circuit setups. However, the parallel A circuit could achieve higher pump output and generate adequate pulsatility level. Thus, the parallel A circuit is suggested as the optimal configuration in T-PLS applications.

Optimization of the Circuit Configuration of a Pulsatile ECLS: An In Vivo Experimental Study

An extracorporeal life support system (ECLS) with a conventional membrane oxygenator requires a driving force for the blood to pass through hollow fiber membranes. We hypothesized that if a gravity-flow hollow fiber membrane oxygenator is installed in the circuit, the twin blood sacs of a pulsatile ECLS (the Twin-Pulse Life Support, T-PLS) can be placed downstream of the membrane oxygenator. This would increase pump output by doubling pulse rate at a given pumpsetting rate while maintaining effective pulsatility. The purpose of this study was to determine the optimal circuit configuration for T-PLS with respect to energy and pump output. Animals were randomly assigned to 2 groups in a total cardiopulmonary bypass model. In the serial group, a conventional membrane oxygenator was located between the twin blood sacs of the T-PLS. In the parallel group, the twin blood sacs were placed downstream of the gravity-flow membrane oxygenator. Energy equivalent pressure (EEP), surplus hemodynamic energy (SHE) and pump output were collected at the different pump-setting rates of 30, 40, and 50 beats per minute (BPM). At a given pump-setting rate the pulse rate doubled in the parallel group. Percent changes of mean arterial pressure to EEP were 13.0 +/- 1.7, 12.0 +/- 1.9, and 7.6 +/- 0.9% in the parallel group, while 22.5 +/- 2.4, 23.2 +/- 1.9, and 21.8 +/- 1.4 in the serial group at 30, 40, and 50 BPM of pump-setting rates. SHE at each pump setting rate was 20,131 +/- 1408, 21,739 +/- 2470, and 15,048 +/- 2108 erg/ cm3 in the parallel group, while 33,968 +/- 3001, 38,232 +/- 3281, 37,964 +/- 2693 erg/cm3 in the serial group. Pump output was higher in the parallel circuit at 40, and 50 BPM pump-setting rates (3.1 +/- 0.2, 3.7 +/- 0.2 L/min vs. 2.2 +/- 0.1 and 2.5 +/- 0.1 L/min, respectively, p =0.01). Either parallel or serial circuit configuration of T-PLS generates effective pulsatility. As for the pump out, the parallel circuit configuration provides higher flow than the serial circuit configuration by doubling the pulse rate at a given pump-setting rate.

Prospective study of acute gastrointestinal bleeding attributable to anti-inflammatory drug ingestion in the Yorkshire region of the United Kingdom

OBJECTIVE

To assess the general use of all non-steroidal anti-inflammatory drugs (NSAID) and their relation to upper gastrointestinal bleeding in view of National Institute for Clinical Excellence guidelines published in July 2001 in the UK.

METHODS

Cross sectional study on all patients who were referred for endoscopy for suspected upper gastrointestinal bleeding in six hospitals in Yorkshire region of the UK.

RESULTS

One hundred and sixty three patients presented for endoscopy for suspected upper gastrointestinal bleeding, 43 patients were taking at least one ulcerogenic drug, and 120 were not. The mean age difference between these two groups was eight years (p<0.01). The absolute difference between the proportion of patients with peptic ulcer disease/erosion (PUD) in NSAID with/without aspirin group and no ulcerogenic drug group was 31% (p = 0.02). The difference between the proportion of PUD in cyclo-oxygenase 2 with/without aspirin group and no ulcerogenic drug group was 30% (p = 0.1). The overall 30 days mortality rate was 14.1%.

CONCLUSIONS

Elderly patients are being inappropriately prescribed conventional NSAIDs. NSAIDs with or without aspirin use are still associated with a significant risk of upper gastrointestinal bleeding in the era of cyclo-oxygenase 2 selective agents. Substitution with cyclo-oxygenase 2 selective NSAIDs is not without risk of upper gastrointestinal bleeding.

Oesophageal haematoma and associated Mallory-Weiss tear

Intramural oesophageal haematoma is a rare condition that may present as vomiting or haematemesis. Mallory-Weiss tear has been proposed as a possible aetiology but the evidence to support this is circumstantial. A case of oesophageal haematoma associated with evidence of Mallory-Weiss tear on endoscopy that helps to support this hypothesis is presented.

Bioequivalence of pravastatin tablet formulations assessed in Korean males

AIM

Determination of the bioequivalence of 2 pravastatin tablet formulations manufactured in Korea.

PATIENTS AND METHODS

Twenty-three healthy male Korean volunteers received each of the 2 pravastatin formulations at a dose of 20 mg in a 2 x 2 crossover study. There was a 1-week washout period between doses. Plasma concentrations of pravastatin were monitored using high-performance liquid chromatography over a period of 8 hours after administration. AUC(0-8h) (the area under the plasma concentration-time curve from time zero to the last measured time in plasma, 8 h) was calculated using the linear-log trapezoidal method. Cmax (maximum plasma drug concentration) and tmax (time to reach Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUC(0-8h) and Cmax and untransformed tmax.

RESULTS

The point estimates and 90% confidence intervals for AUC(0-8h) (parametric) and Cmax (parametric) were 1.067 (0.968 to approximately 1.176) and 1.074 (0.999 to approximately 1.155), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration guidelines. The corresponding value of tmax was 0.000 (-0.250 to approximately 0.250).

CONCLUSION

These results indicate that the 2 medications of pravastatin are bioequivalent and, thus, may be prescribed interchangeably.

Ten year follow up of ulcerative colitis patients with and without low grade dysplasia

BACKGROUND AND AIMS

Low grade dysplasia (LGD) is believed to predispose to colorectal cancer (CRC), and proctocolectomy has been advocated when this is identified. Between 1978 and 1990, 160 patients with longstanding extensive ulcerative colitis (UC) were recruited for annual colonoscopic surveillance and 40 developed LGD at some stage. We report the outcome of this cohort 10 years after the original study ended.

METHODS

Retrospective cohort study and histopathological review of the original diagnoses of LGD. The outcome of 158/160 (98.8%) patients was established in 2000.

RESULTS

Of the 128 patients still alive and with an intact colon at the end of 1990, two were not traceable, 29 had LGD, and 97 had no dysplasia (controls). After 10 years, high grade dysplasia (HGD) or CRC developed in 3/29 LGD (10%) and in 4/97 controls (4.0%). Kaplan-Meier analysis from 1991 to death or colectomy did not show a statistically significant difference between the two groups (log rank test p=0.63). Histopathological review demonstrated the unreliability of LGD diagnosis. Agreement between pathologists was uniformly poor: kappa <0.4 for all comparisons.

CONCLUSION

LGD diagnosis is not sufficiently reliable to justify prophylactic colectomy. Conservative management of established LGD cases should not be ruled out.

Synthesis and binding affinities of 2 beta-(3-iodoallyloxycarbonyl)-3 beta-(4-substituted-aryl)tropane analogues as ligands for the dopamine transporter studies

Tropane analogues from cocaine, which is known to be one of the most reinforcing and addictive compounds, were designed, synthesized, and characterized for inhibition of presynaptic uptake of dopamine (DA) in brain. Eight new derivatives of 3 beta-aryl-2 beta-(3-iodoallyloxycarbonyl)tropanes were synthesized and tested for their potential abilities to displace [(3)H]2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane (WIN 35,428) binding to the rat striatal membranes.

Xenobiotic response in humanized double transgenic mice expressing tetracycline-controlled transactivator and human CYP1B1

The cytochrome P450 enzymes (P450s or CYPs) are a superfamily of hemeproteins that catalyze the monooxygenation of a wide range of endobiotic and xenobiotic substrates. A typical strategy in toxicological research and testing involves applying a toxicant at high doses for a short period to homogeneous animals under controlled conditions. However, the conditions of this approach have very little in common with actual human exposure. Transgenic (Tg) mice carrying human genes encoding a drug-metabolizing enzyme (CYP) offer a solution to many of the difficulties in the evaluation of chemical toxicity. It has been demonstrated that the expression of human CYP transgenes under the control of mammalian-inducible promoters exhibits relatively poor fold increases after induction. In this study, we used the tetracycline-regulated (tet) promoter system to increase the expression of the human CYP1B1 (hCYP1B1) gene in the tissues of transgenic mice. By mating two lineages of transgenic mice, double transgenic (dTg) mice expressing both tTA and hCYP1B1 genes under the control of the tet promoter were successfully produced, into which the two transgenes were introduced in an embryo. The expression pattern of tTA-driven hCYP1B1 transgene featured a fold induction of more than 3 to 12 in the brain, heart, and lung and 2- to 4-fold induction in the liver, kidney, and intestine upon doxycycline removal. Immunohistochemical staining with hCYP1B1 antibody was also increased by the removal of doxycycline. In addition, the activities of CYP liver microsomes in the dTg mice without doxycycline showed an increase compared to that in the dTg mice treated with doxycycline. The level of activities correspond to the levels of human CYP1B1 protein expression in the Tg mice (-dox) that was increased by 2-fold induction as compared to that of the dTg mice with doxycycline. Thus, overproduction in Tg can be purified and the activity of purified human CYP1B1 can be characterized by alterations to the coding sequence in order to solve the physiological function of this enzyme in a humanized in vivo system. It is also possible to examine the activity of purified human CYP1B1 using several environmental toxicants such as procarcinogens.

Occlusive myocardial infarction: investigation of bis-gadolinium mesoporphyrins-enhanced T1-weighted MR imaging in a cat model

PURPOSE

To test whether bis-gadolinium mesoporphyrins-enhanced magnetic resonance (MR) imaging can accurately depict irreversibly damaged myocardium in occlusive myocardial infarction.

MATERIALS AND METHODS

Ten cats were subjected to 90 minutes of occlusion of the left anterior descending coronary artery. Bis-gadolinium mesoporphyrins-enhanced T1-weighted MR imaging was performed in the cats for 6 hours. Histopathologic examinations with 2'3'5-triphenyl tetrazolium chloride (TTC) staining and electron microscopy were performed on the resected specimens. The time course and pattern of signal intensity enhancement were evaluated. The size of the infarcted myocardium was estimated on the MR images by measuring the size of the signal intensity-enhanced area.

RESULTS

In eight of 10 cats, it was impossible to distinguish infarcted myocardium from normal myocardium at visual inspection of T1-weighted MR images. The contrast ratio between infarcted and normal myocardium did not increase significantly over time. In one of the two remaining cats, a doughnut pattern of signal intensity enhancement was noted. The other cat showed intensely homogeneous enhancement of infarcted myocardium at MR imaging. The size of the area of signal intensity enhancement at MR imaging in these two cats was accurately mapped to that of the infarction on the TTC-stained specimens.

CONCLUSION

Occlusive myocardial infarction cannot be accurately detected at bis-gadolinium mesoporphyrins-enhanced MR imaging.

Irreversibly damaged myocardium at MR imaging with a necrotic tissue-specific contrast agent in a cat model

PURPOSE

To investigate the capability of a necrosis-avid magnetic resonance (MR) contrast agent, bis-gadolinium mesoporphyrins, for assessment of irreversibly damaged myocardium and to evaluate the time course of signal enhancement in the reperfused myocardium.

MATERIALS AND METHODS

Nine cats were subjected to 90 minutes of occlusion of the left anterior descending coronary artery followed by 90 minutes of reperfusion. Contrast material-enhanced T1-weighted spin-echo images were obtained for 12 hours in five cats and 6 hours in four cats. Pathologic examinations of the resected specimens were performed with 2'3'5-triphenyl tetrazolium chloride (TTC) histochemical staining and electron microscopy. The size of enhanced area on MR images was compared with that of irreversibly damaged myocardium with TTC staining. The time course of signal enhancement was evaluated.

RESULTS

The size of enhanced area on MR images was well correlated with that of irreversibly damaged myocardium with TTC staining. Maximum enhancement occurred 1-3 hours after administration of the contrast material, with mean enhancement of 171% that of normal myocardium. Electron microscopic examinations showed severe myocardial damage in the irreversibly damaged myocardium but only mild edematous changes in the reversibly damaged myocardium.

CONCLUSION

MR images enhanced with bis-gadolinium mesoporphyrins provide accurate sizing of irreversibly damaged myocardium with a strong and persistent signal enhancement in the reperfused myocardium.