Interplay of Chiral and Helical States in a Quantum Spin Hall Insulator Lateral Junction

We study the electronic transport across an electrostatically gated lateral junction in a HgTe quantum well, a canonical 2D topological insulator, with and without an applied magnetic field. We control the carrier density inside and outside a junction region independently and hence tune the number and nature of 1D edge modes propagating in each of those regions. Outside the bulk gap, the magnetic field drives the system to the quantum Hall regime, and chiral states propagate at the edge. In this regime, we observe fractional plateaus that reflect the equilibration between 1D chiral modes across the junction. As the carrier density approaches zero in the central region and at moderate fields, we observe oscillations in the resistance that we attribute to Fabry-Perot interference in the helical states, enabled by the broken time reversal symmetry. At higher fields, those oscillations disappear, in agreement with the expected absence of helical states when band inversion is lifted.

One-dimensional weak antilocalization due to the berry phase in HgTe wires

We study the weak antilocalization (WAL) effect in the magnetoresistance of narrow HgTe wires fabricated in quantum wells with normal and inverted band ordering. Measurements at different gate voltages indicate that the WAL is only weakly affected by Rashba spin-orbit splitting and persists when the Rashba splitting is about zero. The WAL amplitude in wires with normal band ordering is an order of magnitude smaller than for wires with an inverted band structure. These observations are attributed to the Dirac-like dispersion of the energy bands in HgTe quantum wells. From the magnetic-field and temperature dependencies we extract the dephasing lengths and band Berry phases. The weaker WAL for samples with a normal band structure can be explained by a nonuniversal Berry phase which always exceeds π, the characteristic value for gapless Dirac fermions.

Continuous intraventricular pressure monitoring for diagnosis of normal-pressure hydrocephalus

OBJECTIVES

Normal-pressure hydrocephalus (NPH) syndrome is treatable by implantation of a cerebrospinal fluid (CSF) shunt. However, diagnosis of NPH by clinical and radiological findings alone is unreliable, and co-existing structural dementia can contribute to low success rates after shunt implantation. The aim of our study was to investigate whether long-term results after shunt implantation in NPH improve when surgical candidates are selected by continuous intraventricular pressure monitoring (CIPM).

PATIENTS AND METHODS

Ninety-two consecutive patients who were admitted with suspected NPH received CIPM for 48 h including an intraventricular steady-state infusion test to determine the resistance outflow. With positive CIPM, shunt implantation was performed and the patients were prospectively followed up for 1 to 10 years (median 6.5 years).

RESULTS

CIPM was negative in 37 patients. Fifty-five patients had a positive CIPM and received CSF shunt. 96.1% of them improved from gait disturbance, 77.1% from cognitive impairment and 75.7% from urinary dysfunction. Clinical improvement remained during long-term follow-up in all but 3 patients who showed a decline at 4, 5 and 7 years, respectively. CIPM-related complications (ventriculitis) occurred in only one patient.

CONCLUSION

CIPM is a safe and valuable tool to establish a reliable diagnosis of NPH and to identify promising surgical candidates.

Fecal estradiol and progesterone metabolite levels in the three-toed sloth (Bradypus variegatus)

The present study was carried out to assess the possibility of measuring fecal steroid hormone metabolites as a noninvasive technique for monitoring reproductive function in the three-toed sloth, Bradypus variegatus. Levels of the estradiol (E2) and progesterone (P4) metabolites were measured by radioimmunoassay in fecal samples collected over 12 weeks from 4 captive female B. variegatus sloths. The validation of the radioimmunoassay for evaluation of fecal steroid metabolites was carried out by collecting 10 blood samples on the same day as defecation. There was a significant direct correlation between the plasma and fecal E2 and P4 levels (P < 0.05, Pearson's test), thereby validating this noninvasive technique for the study of the estrous cycle in these animals. Ovulation was detected in two sloths (SL03 and SL04) whose E2 levels reached 2237.43 and 6713.26 pg/g wet feces weight, respectively, for over four weeks, followed by an increase in P4 metabolites reaching 33.54 and 3242.68 ng/g wet feces weight, respectively. Interestingly, SL04, which presented higher levels of E2 and P4 metabolites, later gave birth to a healthy baby sloth. The results obtained indicate that this is a reliable technique for recording gonadal steroid secretion and thereby reproduction in sloths.

Alpha-1-antitrypsin deficiency in children: liver disease is not reflected by low serum levels of alpha-1-antitrypsin - a study on 48 pediatric patients

BACKGROUND

Alpha-1-antitrypsin (alpha1-AT) is an important protease inhibitor. The phenotypes are characterized by a low total serum alpha1-AT or by an abnormal protein accumulating in the hepatocytes. The aim of our study was to examine a correlation of total serum alpha1-AT, phenotype, and liver involvement in pediatric patients.

METHODS

48 patients, deficient for alpha1-AT were included. The phenotypes for alpha1-AT were determined by isoelectric focusing. Liver disease was defined either as elevated transaminases or/and as elevated conjugated bilirubin and gammaGT. Patients were reexamined after a mean interval of 2 years.

RESULTS

Homozygous alpha1-AD was found in 12 patients, heterozygous in 24 patients. In 12 children rare variants of alpha1-AD were diagnosed. Serum alpha1-AT levels less than 60% of normal were found in all patients with homozygous, in 37% of patients with heterozygous alpha1-antitrypsin deficiency (alpha1-AD), and in patients with the homozygous variant PiM(palermo). Liver disease was found in 8/12 patients with the phenotype PiZZ and in 15/24 patients with heterozygous alpha1-AD. Three of 4 patients with the phenotype PiMQ0 had severe liver disease despite normal serum levels for alpha1-AT. In 11 patients with heterozygous alpha1-AD liver disease was apparent despite normal serum alpha1-AT levels. In two patients with the variant type Mpalermo serum levels were as low as 11% of normal without any signs of liver disease.

CONCLUSIONS

Our data clearly show that in the diagnostic workup of neonatal cholestasis measurement of total serum alpha1-AT does not exclude liver disease due to abnormal alpha1-AT variants. We suggest analysis of alpha1-AT-phenotype by isoelectric focussing in patients with unknown liver disease. Heterozygous or rare variant types might remain undiagnosed by measuring total alpha1-AT only.

Differential effects of deoxycholic acid and taurodeoxycholic acid on NF-kappa B signal transduction and IL-8 gene expression in colonic epithelial cells

Several effects of bile acids (BAs) on colonic epithelial cells (CECs) have been described, including induction of proliferation and apoptosis. Some of these effects are mediated through activation of the NF-kappa B transcriptional system. In this study, we investigated the molecular mechanisms underlying the BA-induced gene expression in CECs. The human CEC line HT-29 and primary human CECs were treated with dilutions of salts of deoxycholic acid (DCA) and taurodeoxycholic acid (TDCA). NF-kappa B binding activity was analyzed with EMSA, RelA translocation with immunofluorescence, and I kappa B alpha- and RelA-phosphorylation with Western blot analysis. IL-8 mRNA and protein expression were assessed by quantitative PCR and ELISA. Functional impact of NF-kappa B activation was determined by blocking the proteasome activity with MG132 or by preventing IKK activity with a dominant-negative IKK beta delivered by adenoviral dominant-negative (dn) IKK beta (Ad5dnIKK beta). DCA and TDCA induced IL-8 expression in a dose- and time-dependent manner. It is interesting that DCA but not TDCA induced I kappa B alpha-phosphorylation, RelA translocation, and NF-kappa B binding activity. Accordingly, the proteasome inhibitor MG132 blocked DCA- but not TDCA-induced IL-8 gene expression. In contrast, TDCA-induced IL-8 gene expression correlated with enhanced RelA phosphorylation, which was blocked by Ad5dnIKK beta. Our data suggest that DCA-induced signal transduction mainly utilized the I kappa B degradation and RelA nuclear translocation pathway, whereas TDCA primarily induced IL-8 gene expression through RelA phosphorylation. These differences may have implications for the understanding of the pathophysiology of inflammation and carcinogenesis in the gut.

Early diagnosis of external ventricular drainage infection: results of a prospective study

OBJECTIVES

The aim of this study was to evaluate the influence of total drainage time on the risk of catheter infection, and the predictive value of standard laboratory examinations for the diagnosis of bacteriologically recorded cerebrospinal fluid (CSF) infection during external ventricular drainage.

METHODS

During a three year period, all patients of the neurosurgical intensive care unit (ICU), who received an external ventricular drain, were prospectivly studied. Daily CSF samples were obtained and examined for cell count, glucose and protein content. Bacteriological cultures were taken three times a week, and serum sepsis parameters were determined.

RESULTS

130 patients received a total of 186 external ventricular drains. The ventricular catheters were in place from one to 25 days (mean 7.1 days). In 1343 days of drainage, the authors recorded 41 positive bacteriological cultures in 21 patients between the first and the 22nd drainage day (mean 6.4). No significant correlation was found between drainage time and positive CSF culture. The only parameter that significantly correlated with the occurrence of a positive CSF culture was the CSF cell count (unpaired t test, p<0.05).

CONCLUSIONS

Drainage time is not a significant risk factor for catheter infection. Increasing CSF cell count should lead to the suspicion of bacteriological drainage contamination. Other standard laboratory parameters, such as peripheral leucocyte count, CSF glucose, CSF protein, or serum sepsis parameters, are not reliable predictors for incipient ventricular catheter infection.

Penetration failure and misdiagnosis of stereotactic biopsy caused by the uncommonly firm tissue of a gliomyosarcoma

OBJECTIVE AND IMPORTANCE

We report the very rare case of a gliomyosarcoma that caused penetration failure in stereotactic biopsy and therefore led to misdiagnosis. This complication should be considered as a potential reason for diagnostic failure with uncommonly firm tumors in frame-based stereotactic biopsy.

CLINICAL PRESENTATION

An 83-year-old women presented with a 4-week history of right hemiparesis. Computed tomography (CT) demonstrated a left precentral lesion of 1 cm in diameter with moderate contrast uptake and perifocal edema.

INTERVENTION

Stereotactic biopsy was performed using the Cosman-Robert-Wells (CRW) system and a side-aspirating biopsy needle. Six tissue samples were taken; however, histopathologic examination remained non-diagnostic. Because the hemiparesis had worsened, a magnetic resonance tomography (MRT) was taken four weeks later and clearly demonstrated an increase in size of the lesion. Neuronavigation-guided open surgery revealed a very firm, well-delimited tumor that was classified in the pathologic examination as a gliomyosarcoma. Repeated recalculations of the target coordinates, analysis of the CT scan that was taken 4 days after the stereotaxy, and finally, recognition of the extraordinary firmness of this gliomyosarcoma allowed us to presume with certainty that we had not penetrated the lesion with the biopsy cannula, but rather had merely pushed it ahead of the instrument while the tissue samples were taken.

CONCLUSION

The reported case is both unique for its histopathologic diagnosis and for the complication it caused in stereotactic biopsy. The case also supports the implementation of image-guided interventions for diagnostic biopsy, rather than frame-based stereotaxy in the future.

The lateral transfacetal retrovascular approach for an anteriorly located chordoma originating from the second cervical vertebra

BACKGROUND

Anteriorly located lesions at the craniocervical junction (CCJ) require careful surgical planning to avoid neuraxis retraction. Several different routes have been described in the search for the most appropriate yet least invasive approach. However, most of these far-lateral posterior approaches are specifically tailored for non-osseous intradural tumours or chordomas with cephalad extension. We introduce an approach that allows for better access to laterally extending osseous tumours originating from the second cervical vertebra. Using this approach, the lesion is manipulated from a strictly lateral direction parallel to a plane through the articular pillar of the CCJ and the odontoid process, and the C1- and C2-laminae are spared for posterior fixation.

METHOD

The application of this approach is demonstrated in detail by an illustrative case of a chordoma originating from C2 that presented with intradural mass effect, considerable bone destruction, far-lateral extension to the right, and vertebral artery involvement.

FINDINGS

The described approach gave ample access for total tumour resection. It allowed for safe control and displacement of the vertebral artery, spinal cord decompression, C2-corpectomy across the midline, and anterolateral bone reconstruction. No C1- or C2-hemilaminectomy was needed, and these bone elements could be used for posterior fixation (the patient presented in this study was referred to our institution after posterior fixation from the occiput to C3 had already been performed elsewhere). No intra-operative or postoperative complications occurred. At the 6-month follow-up, the patient was fully ambulatory with no neurological deficit.

INTERPRETATION

The described lateral transfacetal route is the method of choice for operating on laterally extending osseous tumours originating from the second cervical vertebra.

Platelet-derived growth factor-alpha receptor expression supports the growth of conventional chondrosarcoma and is associated with adverse outcome

Bone cells are important targets of platelet-derived growth factors (PDGFs) because they stimulate proliferation of osteoblasts and chondrocytes. In this study we wanted to determine the expression of PDGF-AA and PDGF-alpha receptor in conventional chondrosarcomas and to compare the results with those obtained from benign enchondromas and non-neoplastic cartilage tissue. Sixty-seven chondrosarcomas, 20 enchondromas, and 5 specimens of healthy cartilage as well as 7 specimens of hypertrophic callus cartilage were immunohistochemically analyzed for the expression of PDGF-AA and PDGF-alpha receptor, respectively. Additionally, the proliferation activity was examined with the MIB-1 antibody. Clinical follow-up data were available from 53 patients. A significant overexpression of receptor and factor was found in chondrosarcomas as compared with enchondromas (PDGF-AA p = 0.013, PDGF-alpha receptor p <0.001). MIB-1 values were significantly higher in chondrosarcomas (p <0.001). In healthy joint cartilage no staining was detectable, whereas reactive cartilage of callus formation showed high expression levels. PDGF-alpha receptor expression was significantly higher in grade 3 chondrosarcomas compared with grade 2 (p = 0.022) and grade 1 tumors (p = 0.002). Survival analysis documented a significantly shorter overall survival for patients with high PDGF-alpha receptor expression (p = 0.0172, log-rank test). Because PDGF-alpha receptor expression positively correlates with the aggressiveness of chondrosarcoma, it may be considered as a possible target for novel therapeutic strategies.

[Short-term results of modified chevron osteotomy with soft tissue technique and guide wire fixation--a prospective study]

AIM

A Chevron osteotomy with lateral soft-tissue release was performed at our department in 1993. In 1994 a prospective study to evaluate the temporary Kirschner wire fixation was started. Aim of this prospective study was to analyse the short-term clinical and radiological results with special attention to stability, necroses, and luxation of the first metatarsal head.

METHOD

Between February 1994 and October 1995 45 patients (55 feet) were treated with a Chevron osteotomy combined with a lateral soft-tissue release and temporary Kirschner wire fixation. The average follow-up was 33.9 months. All patients were seen and evaluated preoperatively and at a minimum follow-up of 24 months using a standardized questionnaire based on the Hallux metatarsophalangeal interphalangeal Scale (HMIS) of the American Foot and Ankle Society.

RESULTS

Results of the survey of patient satisfaction revealed excellent and good results in 83%, fair in 8%, and poor in 9%. The median HMIS at final follow-up was 86.9 pints of 100 points. The average hallux valgus angle correction was 19.8 (from 28.7 to 8.9) and the average first intermetatarsal angel correction was, 8.2 (from 14.4 to 6.2). No avascular necrosis of the first metatarsal head and no loss of correction were noted. In one case a luxation of the metatarsal head was observed.

CONCLUSION

Combining the Chevron osteotomy with an excessive lateral soft-tissue release increases the likelihood of instability of the metatarsal head and consecutive loss of correction. The temporary Kirschner wire fixation increases the stability of the Chevron osteotomy and prevents the loss of correction. The disadvantage of this method is, that the wire has to be removed after 6 weeks.

Measurement of the electric form factor of the neutron through d-->(e-->,e(')n)p at Q2 = 0.5 (GeV/c)(2)

We report the first measurement using a solid polarized target of the neutron electric form factor G(n)(E) via d-->(e-->,e(')n)p. G(n)(E) was determined from the beam-target asymmetry in the scattering of longitudinally polarized electrons from polarized deuterated ammonia ( 15ND3). The measurement was performed in Hall C at Thomas Jefferson National Accelerator Facility in quasifree kinematics with the target polarization perpendicular to the momentum transfer. The electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle segmented detector. We find G(n)(E) = 0.04632+/-0.00616(stat)+/-0.00341(syst) at Q2 = 0.495 (GeV/c)(2).

Noncontiguous spinal metastases and plasmocytomas should be operated on through a single posterior midline approach, and circumferential decompression should be performed with individualized reconstruction

BACKGROUND

In noncontiguous spinal metastatic disease, anterior or combined anterior-posterior surgery is an effective treatment. The objective of this study is to investigate whether circumferential decompression through a single-stage posterior midline approach with individualized spinal reconstruction can still achieve comparable results for functional improvement and for maintenance of spinal alignment in the absence of the risks associated with the more invasive transcavitary or combined approaches.

METHOD

Seventeen patients with noncontiguous spinal metastases and plasmocytomas at one or two adjacent levels were included in this series. Circumferential decompression was obtained with anterior reconstruction and posterior fixation in ten patients, and with posterior instrumentation alone in seven patients. Postoperatively the patients were prospectively followed, and their functional status and spinal alignment were periodically evaluated.

FINDINGS

Fourteen patients died from progression of their underlying cancer. Their mean survival time was 8 months (range: 1 to 21 months). Three survivors were evaluated at 10, 4 and 3 months respectively. At one month after surgery, 14 patients (82%) showed neurological improvement. Of 10 preoperative nonambulators, seven regained walking capacity. Five patients who were ambulatory with assistance improved to full functional independence. Local tumour recurrence was recorded in one patient after subtotal vertebrectomy for a plasmocytoma at L5. No other tumour recurrences were noted. In one patient a partial loss of correction occurred at T6 - without functional deterioration, however. Spinal alignment was maintained in all other patients who became or remained ambulatory. No major intra-operative complications or peri-operative deaths occurred. CSF leakage was recorded as the most common complication in four patients.

INTERPRETATION

Circumferential decompression and spinal reconstruction through a single-stage posterior midline approach is feasible and effective. The extent of surgery can be individualized by means of this technique to the patient's specific problem. In patients with limited life expectancy from metastatic neoplastic disease, the results compare favourably with the more invasive anterior or combined antero-posterior procedures.

Minimally invasive retroperitoneal approach for lumbar corpectomy and anterior reconstruction. Technical note

The anterior decompressive procedure in which spinal fusion is performed is considered an effective treatment for thoracolumbar fractures and tumors. However, it is also known to be associated with considerable surgery-related trauma. The purpose of this study was to show that lumbar corpectomy and anterior reconstruction can be performed via a minimally invasive retroperitoneal approach (MIRA) and therefore the surgical approach-related trauma can be reduced. The authors studied retrospectively the hospital records and radiological studies obtained in five patients (mean age 67.4 years, range 59-76 years) who underwent lumbar corpectomy and spinal fusion via an MIRA followed by posterior fixation. Four patients presented with osteoporotic compression fractures at L-2 and L-3, and one patient presented with metastatic disease in L-4 from prostate cancer. Neurological deficits due to cauda equina compression were demonstrated in all patients. The MIRA provided excellent exposure to facilitate complete decompression and anterior reconstruction in all patients, as verified on follow-up radiographic studies. All patients improved clinically. A 1-year follow-up record is available for four patients and a 6-month follow-up record for the fifth patient; continuing clinical improvement has been observed in all. Radiography demonstrated anatomically correct reconstruction in all patients, as well as a solid fusion or a stable compound union in the four patients for whom 1-year follow-up records were available. The MIRA allows the surgeon to perform anterior lumbar spine surgery via a less invasive approach. The efficacy and safety of this technique and its potential to reduce perioperative morbidity compared with conventional retroperitoneal lumbar spine surgery should be further investigated in a larger series.

[Hallux valgus: a therapy concept and its outcome from 1993 to 1996]

INTRODUCTION

Aim of this study is to present the treatment concept and the results of hallux valgus surgery of our department.

PATIENTS AND METHODS

The criteria for decision making are 1st intermetatarsal angle, congruency of the first metatarsophalangeal joint and sesamoid position. According to our concept we performed between 1993 and 1996 42 Chevron osteotomies for mild, 138 Chevron with lateral soft tissue release (Chevron + LSR) for moderate and 93 basal crescentic (Mann) osteotomies with lateral soft tissue release for severe hallux valgus deformities.

RESULTS

31 Chevron, 118 Chevron with lateral soft tissue release and 80 basal crescentic osteotomies (Mann) were seen at an average follow up of 19 months (12-29) after a Chevron, respectively. 16 months (12-43) after Chevron with lateral soft tissue release and 18 months (12-32) after a basal crescentic osteotomy. 83% of all patients classified the results of the surgery as "very satisfactory" and "satisfactory". The average hallux valgus angle was corrected from preoperatively. 25.3 degrees (Chevron), 29.9 degrees (Chevron + LSR) and 41.8 degrees (Mann) to 16.5 degrees (Chevron), 12.1 degrees (Chevron + LSR) and 14.1 degrees (Mann) at final follow up, the average first intermetatarsal angle was corrected from preoperatively 12.1 degrees (Chevron), 14.0 degrees (Chevron + LSR) and 17.4 degrees (Mann) to 7.9 degrees (Chevron), 5.8 degrees (Chevron + LSR) and 7.8 degrees (Mann) at final follow up.

CONCLUSION

Our analysis of the three osteotomies revealed that with this differentiated concept we were able to achieve excellent and good results in more than 80% of our patients. Only with a treatment plan that includes different procedures to address the various stages of hallux valgus can one achieve the optimum result for the patient.

[Short-term outcome of Weil osteotomy in treatment of metatarsalgia]

INTRODUCTION

The aim of this retrospective study was to analyse the short term results after the Weil-procedure for the treatment for metatarsalgia in 30 consecutive patients.

METHODS

30 patients (69 osteotomies) after the Weil-procedure with an average age of 60 years (range 25 to 78 years) were analysed by clinical and radiological evaluation. The average follow up was 15 months (range 12 to 26 months). Analysis was performed using the patients' records, weight-bearing radiographs and a standardized questionnaire.

RESULTS

Subjective evaluation revealed 23 very satisfied and satisfied patients. Based on the Lesser-Metatarsal-Interphalangeal-Scale the objective results showed 77.1 points on average. The results were excellent in 17 cases, good in 4, fair in 3 and unsatisfactory in 6 cases respectively. Recurrent metatarsalgia was noted in 5 cases, whereas no transfermetatarsalgia was observed. The average shortening was 4.4 mm. Subluxation of the metatarsophalangeal joint was corrected in 18 out of 22 cases. A restricted plantar flexion of the metatarsophalangeal joint was noted in 14 cases. 2 patients showed loss of movement.

CONCLUSION

Our short-term results reveal that the Weil-osteotomy is a sufficient treatment for metatarsalgia. This technique is able to reestablish the alignment of the metatarsals and to correct luxation and subluxation of the metatarsophalangeal joint. Restricted plantarflexion of the metatarsophalangeal joint is a drawback, which may be avoided by intensive physiotherapy.

Detection of melanoma cells in the blood of melanoma patients by melanoma-inhibitory activity (MIA) reverse transcription-PCR

The detection of tumor-specific mRNA transcripts in the blood of patients by reverse transcription (RT)-PCR has been used as a very sensitive technique for determining systemically disseminated tumor cells. On the basis of previous expression studies, we aimed to trace melanoma cells in the blood of melanoma patients by RT-PCR of melanoma-inhibitory activity (MIA) mRNA. To detect sensitively MIA transcripts in total RNA isolated from peripheral blood mononuclear cells (PBMCs), we established a sensitive PCR-ELISA system. With this assay, we detected one melanoma cell in 2 ml of blood by a single round of 32 PCR cycles. A total of 295 PBMC samples isolated from 166 patients with melanocytic tumors were tested with the MIA RT-PCR-ELISA: (a) 58 patients (99 samples) with malignant melanomas in stage I; (b) 49 patients (65 samples) with malignant melanomas in stage II; and (c) 47 patients (116 samples) with metastasized melanomas (stages III and IV), with an additional 12 patients (15 samples) with benign melanocytic nevi. Forty-four (26.8%) of 164 samples isolated from patients with melanomas in stages I and II were positive for MIA mRNA; in stages III/IV, 33 (28.4%) of 116 samples of patients, irrespective of clinically evident disease, were positive. Eleven (84.6%) of 13 PBMC samples from patients with metastasized melanoma and clinically evident disease without treatment were MIA mRNA-positive in contrast to only 19 (25.7%) of 74 samples isolated from patients in stage IV with metastasis during chemotherapy. Furthermore, none of the 16 PBMC samples of patients in stage IV without clinically detectable metastases at that time point during chemotherapy was MIA mRNA-positive. Interestingly, of the 44 positive samples (26.8%) isolated from patients with melanomas in stages I and II, 20 were still positive when retested after complete excision of the tumor. Our results reveal that amplification of MIA mRNA from the PBMCs of patients with malignant melanomas by PCR-ELISA provides a useful means to detect tumor cells in the systemic blood circulation. A correlation between positive blood samples and tumor burden in stages III and IV was detected, and, in addition, a significant effect of chemotherapy with respect to the reduction of the number of systemically spread tumor cells was observed. However, MIA amplification seems to be of little value as a surrogate marker for clinical staging or the detection of metastatic disease.

Basal closing wedge osteotomy for correction of hallux valgus and metatarsus primus varus: 10- to 22-year follow-up

Between 1974 and 1985, 59 patients (83 feet) underwent basal closing wedge osteotomy in combination with a bunionectomy and a lateral soft tissue release for correction of hallux valgus and metatarsus primus varus at this institution. Of the original 59 patients, 42 patients (60 feet) with at least 10 years of follow-up (average, 194 months; range, 144-266 months) were available for this study. Results were analyzed by review of the medical records and plain radiographs, a standardized clinical questionnaire, and physical examination. Of the 60 feet, patients rated outcomes as excellent or good in 51 feet (85%) and rated cosmesis as excellent or good in 44 feet (73%). Radiographically at final follow-up, hallux valgus and intermetatarsal angles averaged 19.9 degrees (range, 0-40 degrees) and 6.7 degrees (range, 0-18 degrees), respectively. The sesamoid position was corrected from an average preoperative grade of 2.6 to a grade of 0.9 at final follow-up. The average shortening of the first metatarsal was 5 mm. The disadvantages of the closing wedge osteotomy are that it is technically demanding and it entails the risk of shortening, dorsal malalignment, and metatarsalgia. In the current study, long-term complications included hallux varus deformity (16 feet), dorsal malalignment (15 feet), and metatarsalgia (14 feet). Despite good correction of the intermetatarsal angle and sesamoid position, the clinical results and the incidence of complications after basal closing wedge osteotomy were not as favorable as those reported for other procedures in the literature. Therefore, alternative procedures, such as the basal crescentic osteotomy or the basal chevron osteotomy, should be used.

Comparison of the results of the Weil and Helal osteotomies for the treatment of metatarsalgia secondary to dislocation of the lesser metatarsophalangeal joints

We retrospectively reviewed the outcome of 30 patients who were treated surgically for metatarsalgia resulting from dislocation of one or more lesser metatarsophalangeal (MTP) joints. We used two treatments, including an osteotomy of the metatarsal head (Weil osteotomy, N = 15) or an osteotomy of the metatarsal shaft (Helal osteotomy, N = 15). Before surgery, all patients had been treated with various nonoperative modalities for a minimum of 6 months. Between 1991 and 1993, 15 consecutive patients underwent a Helal osteotomy (22 metatarsals), and 15 consecutive patients were subsequently treated between 1994 and 1995 with a Weil osteotomy (25 metatarsals). All patients were evaluated clinically and radiographically at a mean follow-up period of 22 months (range, 12-39 months), noting especially persistent subluxation or dislocation, recurrent metatarsalgia, and transfer lesions. Patients managed with a Weil osteotomy had significantly higher satisfaction (P = 0.049), lower incidence of recurrent metatarsalgia (0 vs. 27%, P = 0.107), and fewer transfer lesions (0 vs. 41%, P = < 0.001) than those managed with a Helal osteotomy. Furthermore, those managed with the Weil procedure had a higher percentage of radiographic reduction and maintenance of the MTP joint dislocation (21 of 25, 84%; vs. 8 of 22, 36%; P = 0.002) than those managed with the Helal procedure. In the Weil group, there was also no malunion or pseudoarthrosis; in the Helal group there were five malunions and three pseudoarthroses. Although the follow-up period for the Weil osteotomy (15 months) was shorter than that for the Helal osteotomy (26 months), the former group had higher American Orthopaedic Foot and Ankle Society forefoot scores, which were significantly different from the results attained with the Helal osteotomy. A telephone update was performed on the Weil osteotomy group at an average of 27 months postsurgery, and no patient had experienced changes since the clinical follow-up. We concluded that the Weil procedure is a satisfactory method for correcting metatarsalgia caused by dislocation of the MTP joint and that, because of the high complication rate, the Helal osteotomy is not an acceptable procedure for correcting this condition.

The pdr12 ABC transporter is required for the development of weak organic acid resistance in yeast

Exposure of Saccharomyces cerevisiae to sorbic acid strongly induces two plasma membrane proteins, one of which is identified in this study as the ATP-binding cassette (ABC) transporter Pdr12. In the absence of weak acid stress, yeast cells grown at pH 7.0 express extremely low Pdr12 levels. However, sorbate treatment causes a dramatic induction of Pdr12 in the plasma membrane. Pdr12 is essential for the adaptation of yeast to growth under weak acid stress, since Deltapdr12 mutants are hypersensitive at low pH to the food preservatives sorbic, benzoic and propionic acids, as well as high acetate levels. Moreover, active benzoate efflux is severely impaired in Deltapdr12 cells. Hence, Pdr12 confers weak acid resistance by mediating energy-dependent extrusion of water-soluble carboxylate anions. The normal physiological function of Pdr12 is perhaps to protect against the potential toxicity of weak organic acids secreted by competitor organisms, acids that will accumulate to inhibitory levels in cells at low pH. This is the first demonstration that regulated expression of a eukaryotic ABC transporter mediates weak organic acid resistance development, the cause of widespread food spoilage by yeasts. The data also have important biotechnological implications, as they suggest that the inhibition of this transporter could be a strategy for preventing food spoilage.

[Long-term results of basal wedge osteotomy in metatarsus primus varus in the young patient]

INTRODUCTION

Aim of this retrospective study was to analyse the long term results after basal closing wedge osteotomy for correction of metatarsus primus varus and hallux valgus in the younger patient.

PATIENT AND METHODS

49 patients (70 feet) were operated according to a basal closing wedge osteotomy from 1974 to 1985 at our institution. Age was under 40 years in all patients at the time of surgery. 34 patients (50 feet) were evaluated in respect to their clinical and 26 patients (37 feet) to their radiological outcome. The average age was 26 years (14-39 years). The follow-up was 12 to 22 years (Median: 18 years). Analysis was performed using the patient's record, weight-bearing X-rays, a standardized questionnaire and clinical investigation.

RESULTS

82% of the patients had very good and good subjective results. Cosmetics was rated very good and good in 78%, 88% of the patients were painfree. Radiological analysis at follow-up: Hallux valgus-angle 19,3 degrees, intermetatarsal I/II-angle 6 degrees, shortening of first metatarsale 5 mm, at average; dorsal elevation of first metatarsale 38%, degenerative arthritis of the metatarsocuneiforme joint 19%, congruency of first metatarsophalangeal joint 54%,sesamoid subluxation: 46% grade 0, 30% grade I, 14% grade II and 10% grade III. In 14 feet (28%) metatarsalgia was found.

DISCUSSION

The basal closing wedge osteotomy is rather a technically demanding procedure conjuncted with a higher risk of failure. Satisfactory long term results can be obtained by an ideal operating technique. As undesirable side effects shortening of the first ray and dorsal malangulation of the first metatarsale may occur consecutively leading to metatarsalgia. Lower risk procedures like the crescentic osteotomy according to Mann or chevron osteotomy should be preferred.

Experimental laparoscopic and thoracoscopic discectomy and instrumented spinal fusion. A feasibility study using a porcine model

To explore the safety and the effectiveness of laparoscopic and thoracoscopic spinal surgery, an acute/non-survival animal trial was performed in 5 pigs using rigid and flexible endoscopes, flouroscopy, a holmium-YAG laser, and prototype instruments and implants. Our study aimed to approach the intervertebral disc space and spinal canal using laparoscopic and thoracoscopic techniques and to explore the potential and limits for endoscopic anterior spinal decompression and fusion. In a lateral recumbency access was provided to the anterolateral aspect of the lumbar spine from L1/2 to L7/S1, the thoracic spine was accessible from T2/3 to the diaphragmatic insertion. Complete disc space emptying with penetration into the spinal canal could be performed, epidural bleeding could be controlled by a hemostatic sponge, however bleeding restricted visualization for further endoscopic manipulation in the spinal canal. Intervertebral fusion was accomplished at T6/7, L4/5 and L7/S1 using small fragment plates with 3.5 mm screws and iliac bone grafts or prototype carbon fiber cages. On post mortem examination we found no dural tears and no nerve root damage, all animals had stabilized fusion sites and good implant position. We conclude that minimally invasive thoracoscopic and laparoscopic approaches to the spine are feasible and safe to perform disc decompression and implant placement for spinal fusion. In addition to currently performed laparoscopic interbody fusion, also plate fixation to reestablish lordosis of the lumbar spine is feasible at least in the porcine model. Careful disc decompression must be performed prior to implant introduction to prevent iatrogenic disc protrusion and spinal cord or nerve root compression. However, further surgical exploration of the spinal canal using these techniques does not provide adequate visualization of epidural spaces and therefore must be regarded as unsafe.

Acquired hallux varus and clinical tolerability

This retrospective study was undertaken to determine the long-term clinical problems, residual disability, and need for further surgery in patients with iatrogenic hallux varus. Between 1975 and 1985, in 16 (19 feet) of 83 patients who underwent foot surgery for hallux valgus or metatarsus primus varus, hallux varus deformity was noted at 1-year follow-up on dorsoplantar roentgenograms obtained with the patients bearing weight. Thirteen of those patients (16 feet) were reexamined at an average of 18.3 years (220 months) after surgery. The average hallux varus deformity in this group was 10.1 degrees. Eleven patients (12 feet) rated their results as excellent. The average hallux metatarsophalangeal interphalangeal score for all patients was 91.5 points. Only those with extreme hallux varus deformity were dissatisfied or required further surgery.

[CT-assisted definition of puncture site and penetration angle for percutaneous lumbar diskectomy]

In 20 consecutive patients submitted to CT evaluation of a suspected disk protrusion at level L4-5, CT measurements to define entry point and penetration angle for percutaneous diskectomy were performed. It was shown that in order to reach the disk center, the entry point had to be more lateral than recommended by most authors. Body height, weight and body surface area were not significantly correlated to entry point position or penetration angle. In particular, the extension of the intervertebral facet joint determined the route of the probe to the disk center. Therefore, CT-assisted planning of the instrument route prior to percutaneous lumbar diskectomy is helpful in defining the proper entry point and penetration angle for safe and effective instrument positioning.

Cloning and characterisation of genes (pkc1 and pkcA) encoding protein kinase C homologues from Trichoderma reesei and Aspergillus niger

Oligonucleotides, designed on the basis of conserved flanking amino acid sequence segments within the catalytic domain of eukaryotic protein kinase C (PKC) proteins, were used as primers for polymerase chain reactions to amplify a 427-bp chromosomal DNA fragment from the filamentous fungus Trichoderma reesei. This fragment was then used to isolate genes encoding PKC homologues of T. reesei and Aspergillus niger (pkc1 and pkcA, respectively). The genes contain six (T. reesei) and eight (A. niger) introns, which exhibit notable conservation in position with those found in the corresponding Schizosaccharomyces pombe pkc1+ and Drosophila melanogaster dPKC53Ebr genes. A single 4.2-kb transcript was detected in Northern analyses. The deduced PKC1 (T.reesei, 126 kDa) and PKCA (A. niger, 122 kDa) amino acid sequences reveal domains homologous to the C1 and C3/C4 domains of PKC-related proteins, but lack typical Ca(2+)-binding (C2) domains. Both contain a large, extended N-terminus, which shares a high degree of similarity with the corresponding regions of Saccharomyces cerevisiae PKC1 and S. pombe pkc1+ and pkc2+ proteins, but which is not present in PKCs of Dictyostelium or higher eukaryotes. This extended region can be divided into three subdomains; the N-terminal one contains a hydrophobic helix-turn-helix motif, whereas the C-terminal one contains potential targets for proteolytic processing. A polyclonal antiserum raised against the pseudosubstrate-binding domain of PKC1 recognizes in T. reesei a 115-120 kDa protein in Western blots. Expression of pkc1 cDNA in insect cells directs the synthesis of a PKC1 protein of similar size. The T. reesei PKC1 protein was partially purified and some of its properties examined: it is stimulated about twofold by phospholipids or phorbol esters but is not stimulated by Ca2+. We conclude that these PKC proteins from filamentous fungi represent the Ca(2+)-insensitive fungal homologues of the nPKC family.

Stenoses of the first segment of the vertebral artery: difficulties in angiographic diagnosis

Pathology at the origin of the vertebral artery may be the cause of incapacitating vertebrobasilar insufficiency (VBI). Preoperative diagnosis is made primarily on angiographic criteria. We compared intraoperative and angiographic findings in 30 patients and found important diagnostic discrepancies in patients with a caudal, ventral or dorsal origin of the vertebral artery. In their angiograms, vessel superimposition led us to over look 3 ostial stenoses and 10 stenoses due to kinking. Angiographic assessment of patients with VBI can be difficult. Adequate visualisation of the origin of the vertebral artery is mandatory for accurate diagnosis.

[Diagnostic imaging following surgery of spinal disk herniation]

The magnetic resonance imaging findings recorded in patients after surgery for degenerative disc disease in the lumbar and cervical spine are discussed in comparison with conventional radiographs and computed tomography findings. In the lumbar spine normal postoperative findings in the immediate postoperative period can be demonstrated by MR imaging. Contrast-enhanced MR imaging can differentiate disc herniation from postoperative scar formation with a greater degree of confidence than other imaging modalities. MR imaging improves differentiation between other causes of failed back syndrome such as postoperative hematoma and infection, lateral spinal stenosis and arachnoiditis. In the cervical spine types of operative approaches, the appearance of bony stenosis and disc herniations by MR imaging are discussed. Computed tomography still has a role in the assessment of osseous complications such as central or foraminal stenosis.

Spontaneous subarachnoid hemorrhage with negative angiography: CT findings

Computed tomography of 31 patients with spontaneous subarachnoid hemorrhage (SAH) but negative angiography was evaluated to find out whether the pattern of SAH as seen in CT offers indications for a possible reexamination with angiography. Based on the distribution and the amount of SAH, classification into three groups was possible: (a) 18 cases, normal CT (but blood in the CSF, gained by lumbar puncture) or SAH in the basal cisterns only; repeat angiography was negative in all these cases; (b) nine cases, SAH in the basal cisterns as well as in one or both Sylvian fissures; in addition, small amounts of blood in the interhemispheric fissure and/or in the sulci; repeat angiography revealed an aneurysm in one of these cases; (c) four cases, large quantities of blood in all subarachnoid spaces; in all but one of these cases a vascular lesion was visualized with repeat angiography or verified at autopsy. In conclusion, repeat angiography is mandatory in cases with SAH patterns that can be classified into group b or c, whereas it can be omitted in patients with small amounts of blood confined to the basal cisterns.