Lower limb revascularisation preceding surgical wound coverage - an interdisciplinary algorithm for chronic wound closure.

BACKGROUND: Chronic wounds may occur or persist due to arterial insufficiency. Despite the high prevalence of arterial occlusive disease, a search of the literature has yielded a paucity of data on the benefit of interventions to recanalise lower extremity arteries prior to surgical closure of chronic wounds. OBJECTIVE: To investigate the correlation of simple clinical examinations and apparative diagnostics for the detection of arterial occlusive disease of the lower extremity in patients with chronic wounds, and to evaluate the benefit of vascular procedures to optimise wound perfusion before surgical closure. PATIENTS AND METHODS: During a 6-year period, 150 patients with chronic lower extremity wounds (no healing for more than 30 days) were included into this prospective study. All patients underwent palpation of foot pulses, Doppler sonography and measurement of occlusive pressures. Positive clinical findings were re-evaluated by angiography. All patients with peripheral extremity vessel occlusions underwent vascular interventions (percutaneous transluminal angioplasty with stenting, open thrombectomy or vascular bypass surgery) prior to surgical wound closure. RESULTS: In all 34 patients (21%) with missing foot pulses, suspicious Doppler signals or pathological occlusive pressure measurements, the clinical diagnosis of arterial occlusion was confirmed by angiography. An arterial pathology had previously been diagnosed in merely two of those patients. Nineteen patients underwent percutaneous transluminal angioplasty and 21 stents were implanted; in 10 cases, open thrombectomy or vascular bypasses were performed. In all 34 patients, sufficient peripheral recanalisation and improved wound perfusion were successfully achieved. For definitive wound closure, microsurgical tissue transplantation was performed in 15 patients. Angiography was performed prior to surgery. In 11 patients, regional or local flaps were used. Six patients received split skin grafting only; two wounds healed conservatively following vascular intervention. Vacuum-assisted closure (VAC) therapy was applied in 15 cases. Postoperatively, three cases of impaired wound healing and one infection occurred. CONCLUSIONS: Arterial insufficiency can be diagnosed safely by simple clinical examination. All clinically pathological results were successfully confirmed by angiography, allowing for a targeted peripheral vessel reopening to improve wound perfusion before surgery. This straightforward algorithm helped to improve the success of surgical therapy of chronic lower extremity wounds.

[Vascular interventions and reconstructive plastic surgery. Optimizing the treatment of chronic wounds]. / Gefässchirurgische Interventionen und plastisch-rekonstruktive Chirurgie. Ergebnisoptimierung in der Behandlung chronischer Wunden.

Despite the high prevalence of arterial occlusive disease, only a few studies have investigated the benefit of interventions to recanalize extremity arteries prior to plastic operations to close chronic wounds. The purpose of this study was to investigate the correlation of simple clinical examinations and apparative diagnostics of arterial occlusive disease of the lower extremity in patients with chronic wounds and to evaluate the benefit of vascular procedures to optimize wound perfusion before surgical closure. A total of 150 individuals with chronic wounds were included in this retrospective study. All patients underwent palpation of their foot pulses, Doppler sonography, and measurement of occlusive pressure. Positive results were tested by angiography. All patients with peripheral extremity vessel occlusion underwent vascular interventions prior to plastic operations for definitive wound closure. In all 34 patients with missing foot pulses, the clinical diagnosis of arterial occlusion could be confirmed by angiography. Peripheral recanalization and improved wound perfusion could be achieved in all patients. Arterial insufficiency could be diagnosed rapidly and safely using simple clinical examination such as palpation of foot pulses or measurement of occlusive pressures combined with Doppler sonography. Thus this simple and straightforward algorithm helped to secure the success of surgical therapy by shortening the time until wound-healing and reducing the psychosocial burden on the patient and financial costs to the health care system.

Use of the weighted jackknife method to calculate the variance in cellular-specific protein secretion rate: application to monoclonal antibody secretion rate kinetics in response to osmotic stress.

The specific secretion rate (q, microg protein secreted/viable cell-h) and its variance are very useful to compare the capability of cell lines for protein secretion. An assessment of specific secretion rate variability is also beneficial and important when the specific secretion rate is to be used as an on-line process parameter to monitor culture production behavior or for in-process decisionmaking. Experimental errors in mammalian cell culture (e.g., protein concentration measurement and cell counting) and estimation error in the method of calculating q contribute to the total variance of the specific secretion rate. Although the variance of q is essential for comparing the differences between cell lines and the response of the same cell line to different nutrient or environmental conditions, few methods for calculating the variance of the specific secretion rate have been reported. As a model system, we have used the weighted jackknife method and the delta method to calculate the variance in the specific secretion rate of a murine monoclonal antibody (q(mAb)) determined by a differential method. These methods were applied to calculate q(mAb) and its standard deviation to determine the change in q(mAb) kinetics during batch culture of the 9.2.27 hybridoma in response to growth in hyperosmotic media or osmotic stress. Without osmotic stress, during exponential growth in DMEM + 5% FBS spinner culture, the estimate of q(mAb) decreases at least threefold. Results indicate that the 9.2.27 hybridoma responds to hyperosmotic media (400 mOsm, 470 mOsm) by significantly reducing the degree of q(mAb) decrease in the exponential phase, thus maintaining a higher q(mAb) through the stationary phase. The trend of q(mAb) during the batch cultures studied is further confirmed by t-test. Osmotic stress is statistically shown to be able to alter significantly the hybridoma-specific mAb secretion kinetics during batch culture. Determination of the variance of specific secretion rate using the weighted jackknife method offers a powerful approach for establishing the confidence limits of specific protein secretion rate between cell cultures in different nutritional or osmotic environments.

A reanalysis of the Stanton et al. pleural sarcoma data.

An analysis of the Stanton et al. (1981, J. Natl. Cancer Inst. 67, 965-975) data reconfirms number of index particles as the primary dimensional predictor of tumor incidence. Fitting separate intercepts and/or slopes to each mineral type results in substantial significant improvement in fit, indicating the importance of mineral type. This contrasts with the "Stanton hypothesis," which states that dimensional properties alone determine carcinogenesis. Log mean aspect ratio is not as good a predictor of tumor incidence as the number of index particles; among those samples that did not have index particles, log mean aspect ratio is not a significant predictor of tumor incidence.

Analyses for binomial data, with application to the fluctuation test for mutagenicity.

The fluctuation test proposed by Green, Muriel and Bridges (1976, Mutation Research 38, 33-42), a short-term microbial test for mutagenicity, yields binomial observations for which the probability of success varies with the background mutation rate, the total number of microbial growth cycles for which a microbe is at risk of mutation, and the rate of induced mutation for the compound being tested. A standard one-tailed two-sample binomial test is preferable to the two-tailed test adopted by Green et al. for analyzing data from a control versus single positive dose fluctuation test. Based on exact power computations, recommendations are offered for the design of such a fluctuation test. A simple method of guarding against the impact of a small number of aberrant observations in a multisample binomial problem is studied; it is applicable to the fluctuation test when the protocol involves replicate measurements . Finally, the case of more than one positive dose of the test compound is investigated. Two statistical tests for this situation, both extensions of one-tailed two-sample test, are extensively compared. A departure from monotonicity at high doses has a more serious effect on the power of the 'regression' test than on that of the 'isotonic' test. A variant of the isotonic test, based on the angular transformation, should be avoided.

Familial stuttering patterns are not related to one measure of severity.

The possibility of a genetic component to the severity of stuttering was investigated using data on 184 adult stutters and their families. Frequency of stuttering during a pre-treatment oral reading task was used as the severity measure for each of the index cases. Information on whether or not a relative ever stuttered was obtained on all first degree relatives. The family data variables, including sex and exact relationship, combined with birthdate and sex of index case were used in three types of analyses: multiple regressions, AID regressions, and stepwise regressions. None of the variables tested, including stuttering among first degree relatives, was a predictor of severity of stuttering in the index case. We conclude that this measure of severity is not related to the genetic factors which predispose to stuttering.