Three-dimensional recording of the human face with a 3D laser scanner.

Three-dimensional recording of the surface of the human body or of certain anatomical areas has gained an ever increasing importance in recent years. When recording living surfaces, such as the human face, not only has a varying degree of surface complexity to be accounted for, but also a variety of other factors, such as motion artefacts. It is of importance to establish standards for the recording procedure, which will optimise results and allow for better comparison and validation. In the study presented here, the faces of five male test persons were scanned in different experimental settings using non-contact 3D digitisers, type Minolta Vivid 910). Among others, the influence of the number of scanners used, the angle of recording, the head position of the test person, the impact of the examiner and of examination time on accuracy and precision of the virtual face models generated from the scanner data with specialised software were investigated. Computed data derived from the virtual models were compared to corresponding reference measurements carried out manually between defined landmarks on the test persons' faces. We describe experimental conditions that were of benefit in optimising the quality of scanner recording and the reliability of three-dimensional surface imaging. However, almost 50% of distances between landmarks derived from the virtual models deviated more than 2mm from the reference of manual measurements on the volunteers' faces.     

Methods of Measuring Community Characteristics

There is increasing interest in the influence of community characteristics on child development and family functioning. In order to address questions on community influence, it is important to be aware of the measures available and their strengths and limitations. Useful strategies have been developed within a number of disciplines, including sociology, social and community psychology, and criminology. Methods include summarising information from existing administrative databases and census data, conducting observations, and using survey instruments with residents. The most commonly used methods are reviewed and their psychometric properties described .     

Education in family and community health: the challenge faced by a new medical school

This paper describes the efforts of the Department of Family and Community Health at Sultan Qaboos University in providing opportunities for the development of 'hands-on' problem-solving skills appropriate for Oman. The curriculum of the Department is discussed, highlighting the unusual emphasis of this discipline in both the preclinical and clinical curriculum of the College of Medicine. The importance of continuous assessment and supervision of students is discussed. Course-work in the preclinical curriculum of the Department is kept to a minimum. Field-work forms an important part of preclinical training, where application and problem-based learning are emphasized. During the clinical years the students are exposed to an integrated series of lectures and practicals covering core knowledge in clinical medicine. Practical clinical training, over a total period of 15 weeks, takes place at a variety of sites where common problems in primary health care in Oman are handled by students under supervision.     

连续肾替代治疗对严重烧伤脓毒症患者血浆内毒素和细胞因子水平的影响

目的　分析连续肾替代治疗 (continuousrenalreplacementtherapy,CRRT)对严重烧伤脓毒症患者血浆内毒素和细胞因子水平的影响。　方法　对 10例应用CRRT及 10例应用常规疗法治疗的严重烧伤脓毒症患者血浆内毒素和细胞因子 (TNFα、IL 1β、IL 6、IL 8)浓度变化进行比较分析。　结果　严重烧伤脓毒症患者应用CRRT后血浆内毒素、细胞因子浓度较治疗前明显下降 ,其下降速度与常规治疗组比较差异有非常显著性意义 (P <0 .0 1)。　结论　严重烧伤脓毒症患者应用CRRT能有效降低血浆内毒素和细胞因子浓度     

Electrical impedance scanning in breast tumor imaging: correlation with the growth pattern of lesion

Background This study researched the electric impedance properties of breast tissue and demonstrated the differentcharacteristic of electrical impedance scanning (EIS) images.Methods The impedance character of 40 malignant tumors, 34 benign tumors and some normal breast tissue from 69patients undergoing breast surgery was examined by EIS in vivo measurement and mammography screening, with aseries of frequencies set between 100 Hz-100 kHz in the ex vivo spectroscopy measurement.Results Of the 39 patients with 40 malignant tumors, 24 showed bright spots, 11 showed dark areas in EIS and 5showed no specific image. Of the 30 patients with 34 benign tumors there were almost no specific abnormality shown inthe EIS results. Primary ex vivo spectroscopy experiments showed that the resistivity of various breast tissue take thefollowing pattern: adipose tissue＞cancerous tissue＞mammary gland and benign tumor tissue.Conclusions There are significant differences in the electrical impedance properties between cancerous tissue andhealthy tissue. The impedivity of benign tumor is lower, and is at the same level with that of the mammary glandulartissue. The distinct growth pattern of breast lesions determined the different electrical impedance characteristics in theEIS results.     

Pharmacokinetics of piperacillin and tazobactam in critically ill patients with renal failure, treated with continuous veno-venous hemofiltration (CVVH)

Objective: Kinetics of piperacillin (pip), in combination with the beta-lactamase inhibitor tazobactam (taz) have been studied in volunteers and patients in relatively stable conditions. The fixed drug preparation appeared to have ideal pharmacokinetic properties if renal function was normal or slightly impaired, but no data are available for critically ill patients in anuric renal failure. This study should provide such data. Patients, design: We studied the pharmacokinetics in nine patients with multiple organ failure, including anuric renal failure, treated with continuous veno-venous hemofiltration (CVVH). Patients received a standard schedule of 4 g pip and 0.5 g taz administered over 0.5 h intravenously, 8 hourly. During 2 consecutive days, the serum levels of both compounds were determined, and total clearance (CI_T) was calculated from serum concentrations. Results: All nine patients completed day 1, and 8 completed day 2 of the protocol. On day 1, single-dose kinetics showed considerable spread, but pip/taz serum levels followed the pattern as expected, with a pip / taz concentration ratio of 20 : 1. On day 2, however, taz serum concentrations showed a relative increase as compared to pip, resulting in a change in the serum pip/taz concentration ratio to 10 : 1 on day 2. The CI_T of pip was 2.52 ± 1.38 l/h (t ¹/₂ : 5.9 ± 2.9 h), and CI_T of taz 4.44 ± 2.28 l/h (t ¹/₂ : 8.1 ± 3.7 h). The CI_T and t ¹/₂ of pip and taz correlated highly significantly with clearance by CVVH. Despite a higher CI_T, taz has a longer half-life, because of a higher volume of distribution. Conclusion: In CVVH dependent patients, pip/taz fixed drug preparations can be used initially, but the pip dosage should be increased relative to that of taz (or interval-adjusted) to prevent cumulation of taz, as compared to the active antimicrobial agent pip. Received: 19 February 1997 Accepted: 20 May 1997     

Limitations of a thermal camera in measuring surface temperature of laser-irradiated tissues

Thermal cameras are used in research laboratories to measure tissue temperature during laser irradiation. This study was an evaluation of the accuracy of a 3-5 microns thermal camera and two 8-12 microns cameras in detecting the maximum temperatures of small targets. The size of the targets was within the range of laser spot diameters which are used for vessel welding, angioplasty, and dermatology. The response to a sharp thermal edge was measured and analyzed for the three cameras, which had a scanning rate of 30 frames per second. The response of the 3-5 microns camera to reference black body targets of different sizes was also studied. It was found that the detector system required an average of 2.44 microseconds to reach 90% of maximum step response for the 8-12 microns system and 5.85 microseconds for the 3-5 microns system. With a 3 x telescope and a 9.5 inch focal distance close-up lens, the 3-5 microns camera underestimated the temperature of targets smaller than 2.0 mm because of its slow detector response. Although the 8-12 microns camera provides more accurate measurements due to its faster detector response, it still underestimates the temperature of targets smaller than 900 microns, when similar magnification and focal distance are used. Methods to compensate for the inaccuracies are discussed, including empirical correction factors and the inverse filtering technique.     

Continuous arteriovenous haemofiltration in the treatment of tumour lysis syndrome

The management of tumour lysis syndrome remains problematic despite the rigorous use of preventative measures. Continuous arteriovenous haemofiltration (CAVH) is well suited to its use in both the prevention and treatment of metabolic abnormalities and renal insufficiency associated with tumour lysis. We report the successful use of CAVH in the treatment of a patient with tumour lysis syndrome.     

Microalbuminuria and nerve conduction velocity in type-I diabetics during conventional therapy and during continuous I.V. insulin infusion

Summary The objective of this study was to follow the development of microalbuminuria and nerve conduction velocity under continuous i.v. insulin therapy over a limited period of 4 months. For this purpose, 8 labile type I diabetics were selected (age 33±8 years, duration of diabetes 16±9 years) and treated conventionally with two insulin injections daily over 4 months. Afterwards, the same patients were treated with continuous i.v. insulin infusion and finally again with two injections daily over 4 months each. This procedure allowed each diabetic to serve as his own control. HbA₁, microalbuminuria, nerve conduction velocity and relative refractory period of the ulnar nerve were checked at montly intervals. During the continuous i.v. infusion over 4 months, blood sugar values were significantly lower, glucosuria had disappeared almost completely and the glycosylated hemoglobin had fallen to near normal values. The mean rate of albumin excretion was 16±5 μg/min at rest and 76±26 μg/min during exercise (normal: 3.9±0.4 and 4.8±1.2 μg/min, respectively) and did not change significantly. Nerve conduction velocity in the ulnar nerve rose significantly under i.v. insulin therapy from 47.9±0.6 m/sec to 52±0.6 m/sec. Similarly, the relative refractory period of the same nerve fell significantly from 3.7±0.2 to 1.9±0.1 msec (i.e. to within normal range). It is concluded that functional disturbances of peripheral nerve can regress by improved blood sugar control with continuous i.v. insulin infusion over 4 months. On the other hand, incipient microangiopathy measured as microalbuminuria remains unchanged over the same period of time. If an improvement is at all possible, considerably longer periods of euglycemia are likely to be necessary. Supported by Grant No. 3.964-0.80 from the Swiss National Science Foundation.     

乳腺钼靶片计算机光密度测定的临床应用研究

目的：利用计算机对乳腺钼靶片上病灶中心及病灶周围影像光密度的测定，来探索良、恶性乳腺病变之间以及各种病变病灶中心与病灶周围影像的密度差异：探讨病理基础和临床意义。材料和方法：随机选取１００例临床可扪及乳腺＂肿块＂的女性病人，进行乳腺钼靶Ｘ线检查，将检出病变的１０２张钼靶片进行计算机处理后，对病灶中心及病灶周围组织影像的光密度进行测定。所有病例除炎性病变外均取得病理结果。结果：１．良性病变的病灶中心密度与病灶周围密度无显著差异（Ｐ＞０．５），良性肿块（指纤维腺瘤和囊肿）的病灶中心与病灶周围密度间仅提示一种可能存在显著差异的趋势（０．１＞Ｐ＞０．０５）；２．乳腺癌病灶中心与病灶周围密度之间存在非常显著的差异（Ｐ＜０．００１）；３．良、恶性肿瘤病灶中心密度之间存在较显著差异（Ｐ＜０．０５）。结论：本研究的结果有助于乳腺良、恶性病变的鉴别诊断和提高早期乳腺癌的检出率。