A method for a mechanical characterisation of human gluteal tissue

The most common complication associated with immobilization is pressure sores caused by sustained localized tissue strain and stress. Computational simulations have provided insight into tissue stress-strain distribution, subject to loading conditions. In the simulation process, adequate soft tissue material parameters are indispensable. An in vivo procedure to characterise material parameters of human gluteal skin/fat and muscle tissue has been developed. It employs a magnetic resonance imaging (MRI) device together with an MRI compatible loading device. Using the derived data as constraints in an iterative optimization process the inverse finite element (FE) method was applied. FE-models were built and the material constants describing skin/fat and muscle tissue were parameterized and optimized. Separate parameter sets for human gluteal skin/fat and muscle were established. The long-term shear modulus for human gluteal skin/fat was G_{infinity, S/F}= 1182 Pa and for muscle G_{infinity, M} = 1025 Pa. The Ogden form for slightly compressible materials was chosen to define passive human gluteal soft tissue material behaviour. To verify the approach, the human skin/fat-muscle tissue compound was simulated using the derived material parameter sets and the simulation result was compared to empirical values. A correlation factor of R;{2} = 0.997 was achieved.

[In vivo proton MR spectroscopy of normal liver parenchyma: technique and results]

PURPOSE

To analyze the proton magnetic resonance spectroscopic data ( (1)H MRS) of normal liver parenchyma with regard to age, sex, body mass index and location in the liver.

MATERIALS AND METHODS

45 healthy volunteers age 24 to 65 years were examined with an optimized single-voxel (1)H MRS using a 1.5-T scanner. A spin echo sequence with a TR of 1500 ms and a TE of 135 ms was used, allowing in-phase detection of the choline signal. Weak water suppression was achieved using a chemical shift selective suppression (CHESS) technique. Each examination included the measurement of three voxels with a voxel size of 18 x 18 x 18 mm (3) in different areas of the liver. The volunteers were divided into different age-based groups (young: < or = 44 years; older: > or = 44 years), BMI (normal weighted: < 25 kg/m (2); obese: > 25 kg/m (2)) and sex.

RESULTS

In the acquired spectra different lipid (e. g. [CH (2)] (n)), choline, glutamine, glutamate and glycogen-glucose-complex resonances were detected. The analysis of the spectra, however, only focused on the concentrations of choline and (CH (2)) (n) and the relative concentrations of the choline-to-(CH (2)) (n)-ratios. In the older volunteers the relative concentration of the choline-to-(CH (2)) (n)-ratio was significantly decreased by 0.213 +/- 0.193 in comparison to the younger subjects (p = 0,031). Further statistical analysis confirmed a significant decrease of the choline-to-(CH (2)) (n)-ratio by 0.223 +/- 0.180 in obese volunteers compared to volunteers of a standard weight (p = 0,016). The significant difference between the choline-to-(CH (2)) (n)-ratio in female versus male volunteers was calculated with an increase of 0.483 +/- 0.172 (p = 0,000). The location of the voxel in the liver parenchyma did not yield a significant difference in the choline-to-(CH (2)) (n)-ratio.

CONCLUSION

The analysis of the proton liver MRS of healthy volunteers indicated a significant difference in the choline-to-(CH (2)) (n)-ratio depending on age, sex, and BMI with a confidence interval of 95 %. The different choline-to-(CH (2)) (n)-ratio could be the result of the body fat distribution depending on age and sex and also of the increased fat portion of the body in obese volunteers.

Neurogenes Thoracic-outlet-Syndrom

OBJECTIVES

Neurogenic thoracic outlet syndrome (TOS) is one of the most controversial entrapment syndromes of the upper extremity. There are two different surgical approaches for its primary surgical treatment: supraclavicular decompression and transaxillary first rib resection. The aim of this study was to evaluate long-term results and surgical risks of the former.

METHODS

This retrospective long-term study examines a series of 50 supraclavicular decompressions in 45 patients. Follow-up was for at least 24 months. All patients were reexamined regularly in nonstandardized fashion. Finally, each patient underwent a telephone interview with a standardized questionnaire.

RESULTS

There was a significant deterioration of primary results during follow-up. About 30.0% of cases worsened within 24 months after operation. In the long run, about 80.0% of cases showed improvement of symptoms (26.0% excellent, 36.0% good, 18.0% moderate). The complication rate was 4.0%.

CONCLUSION

Due to secondary deterioration of treatment during follow-up, only long-term studies are suited for the examination of neurogenic TOS. Results after supraclavicular decompression are satisfactory, and the complication rate is low.

Approach-related complications of transthoracic spinal reconstruction procedures

Direct surgical repair of instabilities of the anterior spinal column has gained in importance. New techniques and instruments have led to better operative results. Inspite of the growing number of interventions at the anterior spinal column only little data is available on the typical intra- and postoperative complications of these anterior approaches Between 4/1998 and 8/2002, 85 patients in two neurosurgical centres were treated using an anterolateral transthoracic approach for various lesions of the thoracic and thoracolumbar spine. We used a minithoracotomy with video-endoscopic guidance in 75 of these patients. Intra- and postoperative complications were evaluated retrospectively. Two operations had to be abandoned, in all other cases surgery was performed as planned. Postoperatively, eleven patients complained of temporary intercostal neuralgia (12.9%), two patients (2.3%) had a pulmonary insufficiency which was treated conservatively, another patient needed drainage of a pleural effusion. One intraoperative injury to the thoracic duct was treated conservatively, one hernia of the abdominal wall had to be corrected surgically. Relevant injuries to the vessels did not occur, blood loss was 520 ml on average. There was no surgical mortality; one revision surgery had to be performed because of bone graft dislocation. The rate of severe approach-related complications was 4/85 = 4.7% (two abandoned procedures, one injury to the thoracic duct, one abdominal hernia). Transthoracic anterolateral stabilisation via a minithoracotomy with video-endoscopic guidance is an effective surgical approach to treat instabilities of the anterior parts of the thoracic spine and the thoracolumbar area with low complication rates.

First clinical experiences with a new cervical fixation device - technical report

In a first clinical series of ten patients the new cervical fixation device StarLock trade mark (Synthes, Umkirch, Germany) was implanted.[nl]Characteristics of the device are deep threaded screws with higher pullout resistance and a high angular tolerance while inserting the rods thus simplifying the implantation.[nl]62 lateral mass screws in ten patients were inserted. In 2 cases placement of screws was insufficient (3.2 %) because of surgical difficulties not attributable to the system technique.[nl]In all other cases a radiologically proven stabilization was created. [nl]Due to the high angular tolerance of the screw clamps bending of rods is simplified, especially in cases of longer constructs, and shortens the operation time.[nl]The design of the StarLock trade mark system allows an easy application of computer-navigated placing of transpedicular screws.[nl]This new cervical fixation device is easy to handle and simplifies rod application especially in longer constructs.

Switzerland, the law, and HIV: an overview

From the first appearance of HIV/AIDS in Switzerland in the mid 1980s, various legal tools have been implemented to combat the disease, most of them based on legislation already in force. To date, there has been no specific AIDS-related legislation, but if the formal legal framework has changed very little, practice has developed and demonstrates the extent to which the law reflects current societal values. At the risk of "giving the game away," it must be said at the outset that there are virtually no major HIV/AIDS-related legal problems in Switzerland.

Case reports of symptomatic metastases in four patients with primary intracranial gliomas

Four patients with primary intracranial high-grade gliomas are reported. Three of them developed spinal symptoms and signs generated by spinal metastases a few months after first diagnosis, the last patient developed an extraspinal metastasis in cervical lymph nodes. The spinal metastasis of a 30 years old patient was located intradurally at L5/S1, in the second patient at level L3, the third patient presented with multiple metastases in the cervical, thoracic and lumbar spine. Previously reported cases are reviewed, are discussed in the light of our own observations and analysed for the various therapeutic options.

Differential regulation of endothelial cell adhesion molecule expression by nitric oxide donors and antioxidants

Although nitric oxide (NO) and antioxidants inhibit adhesion molecule expression, their inhibitory effects on nuclear factor kappaB (NF-kappaB) activation may differ. The NO donors, but not 8-bromo-cGMP, decreased tumor necrosis factor alpha (TNF-alpha)-induced VCAM-1, ICAM-1, and E-selectin expression by 11-70%. In contrast, NAC completely abolished VCAM-1 and E-selectin expression and decreased ICAM-1 expression by 56%. Gel shift assays demonstrate that NF-kappaB activation was inhibited by both NO and antioxidants. The activation of NF-kappaB involves the phosphorylation and degradation of its cytoplasmic inhibitor IkappaB-alpha by 26S proteasomes. The 26S proteasome inhibitor MG132 prevented the degradation of phosphorylated IkappaB-alpha. NAC inhibited IkappaB kinase (IKK) activity and prevented IkappaB-alpha phosphorylation and degradation. In contrast, NO did not inhibit IKK activity, IkappaB-alpha phosphorylation, or IkappaB-alpha degradation. However, NO, but not antioxidants, induced IkappaB-alpha promoter activity. The inhibitory effects of NO on adhesion molecule expression, therefore, differs from that of antioxidants in terms of the mechanism by which NF-kappaB is inactivated.

[The value of aspiration cytology within the scope of triple diagnosis of palpable breast changes]

The diagnostic value of aspiration cytology and the overall diagnostic quality of the so-called triple test (aspiration cytology, mammography and physical examination) in the evaluation of palpable breast masses were investigated in a retrospective study. 608 histologically evaluated cancers and 224 benign lesions were investigated. A main purpose of the study was to find out whether the triple diagnostic test can replace surgical biopsy and thereby reduce the number of unnecessary biopsies. All lesions triple-diagnosed as malignant were histologically proved to be malignant, i.e. there were no false positive results. The rate of false negative results was found to be within the range reported for false negative results in fresh frozen sections. Based on these results we state that the dogmatic statement "every palpable mass in the breast must be excised" should be replaced by the recommendation "every palpable mass must be assessed and clarified". A great number of retrospectively unnecessary biopsies can be avoided by a systematic use of the triple diagnosis. The diagnostic safety of this method is close to that of open biopsy. In all cases where positive or negative concordant triplets are found, histological confirmation by biopsy can be avoided. Patients with benign lesions can be thoroughly followed up by repeated physical and radiological examinations. Patients with triple diagnostic malignant results can be adequately treated. Lesions for which triple diagnosis yields neither benign nor malignant, must be biopsied: This is also necessary in all cases with suspicious findings in mammography without a palpable mass, if the equipment for stereotactic or ultrasound- guided biopsies is not available.(ABSTRACT TRUNCATED AT 250 WORDS)

[Doppler ultrasound findings in hemodilution with hydroxyethyl starch in intrauterine fetal retardation]

The surveillance of IUGR is one of the main indications of Doppler ultrasound for use in obstetrics. The volume replacement with hydroxyethyl starch is an effective therapy against plasma volume contraction diagnosed by an increase of hematocrit above 38%, which is often combined with IUGR. 48 patients with those problems were treated with middle molecular hydroxyethyl starch for at least 10 days. Doppler ultrasound was used before, within and after therapy. 39 of 48 patients (81%) showed pathological Doppler results in at least one of the examined vessels (uterine artery, umbilical artery, fetal aorta and middle cerebral artery). There is a correlation between normalisation of Doppler results, decrease of hematocrit and increase of the fetal growth indicated by ultrasound or birth weight, respectively. This therapy seems to be useful if it starts between 28th and 34th week of pregnancy; if we find at most two vessels with pathological Doppler results; and if there is an improvement of the Doppler results within therapy. A poor effect is to be expected if therapy begins after 36 weeks of pregnancy, if no change in pathological Doppler results can be found, if fetal vessels show pathological Doppler results and if there is a "notching" in the uterine artery. The group of patients with intrauterine growth retardation can be specified by Doppler ultrasound, which may profit from volume replacement. Doppler examinations are helpful to fetal surveillance within this therapy.

[Uterine rupture in the 22nd week of pregnancy in placenta percreta]

The placenta percreta is a rare event in pregnancy. A case of spontaneous rupture of the uterus in the 22nd week caused by placenta percreta (verified by histological examination) is described. Causal facts and therapeutic aspects are discussed.

[Uroflowmetry and ultrasound residual urine determination in pregnancy and post partum]

In order to estimate the influence of adaptational processes during pregnancy and post partum on micturition, uroflow-parameters (3) and residual urine were examined in 119 healthy women. Comparisons were made between women in the 1st, 2nd and 3rd trimester of pregnancy, women who were between 1 and 5 days post partum and nonpregnant, fertile women. Compared with the control group the mean flow was significantly lower during the 2. and 3. trimester. Time taken to achieve maximum flow was significantly higher after spontaneous delivery compared with the control group. During pregnancy and after delivery an increase in flow time could be shown. During the 3rd trimester time taken to achieve maximum flow was noticeably higher than in the other groups. Both mean and maximum flow were lower during pregnancy and after spontaneous delivery than in the control group. Residual urine increased mainly during the 1. trimester and showed the highest value after delivery. As all the investigated differences stayed within the standardized values, uroflowmetric investigations and ultrasonic residual urine estimation during pregnancy and after delivery are only necessary if suspicious symptoms on the part of the urinary tract exist.

[Twin pregnancy in uterus didelphys]

A case of twin pregnancy in uterus didelphys is reported. This rare event is discussed from obstetric aspects as well as that of dizygotic twins.

[The value of vaginal sonography in advanced, intact extrauterine pregnancy]

The diagnostic problems are discussed in an actual case of a vital extra-uterine pregnancy in the thirteenth week p.m. The value of endosonography and the advantages are compared with the usual abdominal scan tests. The routine use of vaginal endosonography in early pregnancy appears justifiable.

Minimal andrological requirements for in-vitro fertilization

The ejaculate used for in-vitro fertilization of human oocytes must fulfil minimum requirements. Based on the results of experimental investigations, total concentrations of spermatozoa must be greater than 5 million spermatozoa/microliters with progressive motilities of at least 30% and also a normal morphology of at least 30%. Furthermore, in sperm preparations used for inseminating human oocytes, the concentration of pathogenic microorganisms must not be less than 10(4). If there are positive bacteriological findings, the treatment of both partners is mandatory according to the antibiogram. According to the information gathered to date, the hamster oocyte penetration test can only provide additional information if it is positive, but acceptance into an IVF programme should not depend on this test. According to the results presented so far, the swell test developed by Jeyendran shows quite good correlation with the fertilization of human oocytes.

The use of a vaginal probe in the diagnosis of ectopic pregnancy

75 patients with suspected ectopic pregnancy, referred to the department of Gynaecology and Obstetrics of the RWTH-Aachen between July 1987 and May 1988, were examined by means of transvaginal sonography. The sonographic findings were subsequently vaudated by clinical and/or surgical means. An ultrasound diagnosis of an ectopic pregnancy could not be confirmed in only 3 out of 25 such cases.

[Clinical experiences with intracervical prostaglandin E2 administration for labor induction]

From January 1, 1986 to December 31, 1987, 119 patients among a total number of 2309 were recorded prospectively, who needed induction of labour for mixed indications (Group A), for a premature rupture of the membrane (Group B) or for medical indication (Group C). Independently of the ripe of cervix the results were significantly better in the multiparae than nulliparae respecting the success of induction, the duration of labour and the rate of Caesarean sections. 66.4% (n = 79) of all cases could be delivered within 24 hours after the first gel-application. Statistically significant differences in the partial collectives A, B, and C were seen only by unripe cervix (A = 60.0%, B = 71.4%, C = 30.0%). Repeated tries of inductions led to statistically significant more rates of Caesarean sections, fever during labour and prolonged course of labour. The rate of Caesarean sections and the fetal post-partum results comparing to the other remaining deliveries in 1986/87 were statistically not different. Side effects induced by Prostaglandins were only founded in two cases concerning nausea. Uterine hyperactivities with pathological CTG-patterns being resistant to treatment with beta-mimetics were found in one case. As severe complication the only case with particular rupture of uterus must be seen. Based on our experience the intracervical PGE2-application for induction of labour is not disadvantageous for mother and fetus, if there are certain indications and fixed criteria.

[Effect of risk factors on premature labor and neonatal condition following delivery]

The influence of risk factors on the course of pregnancy in cases of preterm delivery, and on the mortality and morbidity of the premature infants, was investigated in a retrospective study. Data of 574 patients who bore children weighing under 2500 g between 1976 and 1986, and of a control group of 574 patients who gave birth during the same period to infants weighing over 2500 g were statistically analyzed. In the preterm population there was a significantly higher incidence of previous treatment for sterility, repeated miscarriages and prior preterm births. Smoking doubles the risk of preterm birth. Pathologic Apgar scores and acidosis morbidity were found significantly more frequently among mothers who smoked. The mortality and morbidity of the neonate depend on its birthweight and the duration of pregnancy. A considerably better prognosis may be expected if the infant weighs over 2000 g and is born after the 32nd week of gestation.