Correlation of radiographic parameters and patient satisfaction in adolescent idiopathic scoliosis treated with posterior screw-dual-rod instrumentation

PURPOSE

In surgical treatment of adolescent idiopathic scoliosis (AIS), only a few studies measure both, radiological parameters and PROMs and correlate them.

METHODS

Prospectively collected AIS-data of one scoliosis-center within a multicenter German-Spine-Society-Study. All patients underwent instrumented posterior spinal correction and fusion with pedicle-screw-dual-rod-systems from 05/2019 to 01/2021. The data were retrospectively analyzed.

INCLUSION CRITERIA

age 11-17 years, follow-up (FU) at least 12 months. Clinical data, radiographic parameters, and PROMs (SRS-30-questionnaire) were collected. 100% of patients had X-ray images, 88.2% completed SRS-30. Parameters were given as mean ± SD. Differences and subdivision by lower instrumented vertebra (LIV) were analyzed by students t-test (significancy a = 0.05), associations by Pearson's correlation.

RESULT

Total of 51 patients: 15 ± 1.4 years, BMI 20.7 ± 3.7 kg/m2, FU 16.6 ± 6.1 months, fusion length 9.2 ± 2.3 segments, implant density 93 ± 9%, surgical time 215 ± 71 min, mean blood loss 504 ± 360 ml. Mean preoperative Cobb angle of main curve 64 ± 14°, of secondary main curve 46 ± 12°, corrected by 68 ± 11%, 56 ± 17%, respectively. Mean thoracic rib and lumbar hump significantly decreased by - 8.5 ± 7.0° and - 7.7 ± 8.9° (p < 0.5). High thoracic rib hump almost unchanged, - 0.4 ± 2.8° (p = 0.3). Thoracic kyphosis (- 0.9 ± 12.8°, p = 0.6), lumbar lordosis (1.5 ± 10.1°, p = 0.3), clavicle angle (- 0.5 ± 2.7°) and spinopelvic parameters (p > 0.5) did not significantly change, only LIV-tilt from 24.5 ± 6.7° to 6.5 ± 4.3° (p < 0.05). PROMs significantly improved (p < 0.05), no significant improvement for function/activity (p = 0.4). Preoperative mean total-score was 3.6 ± 0.5, 4.2 ± 0.3 at FU(p < 0.05). Self-image improved in 67%. Moderately strong correlation for PROMs: the better LIV-tilt (r = - 0.5) correction and the shorter surgery time (r = - 0.4), the better SRS-30 total-score. No correlation for curve correction and patient's satisfaction.

CONCLUSION

In summary, results of this study demonstrate good surgical correction and significant improvement of most PROMs.

[Increased risk of thoracic hypokyphosis after posterior spinal correction and fusion in adolescent idiopathic scoliosis with thoracic double curve]

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is often associated with thoracic hypokyphosis or even lordosis.

OBJECTIVES

To analyze the influence of posterior correction and fusion in thoracic, structurally double-curved AIS.

MATERIAL AND METHODS

Out of 127 thoracic AIS (Lenke types 1 and 2) recorded prospectively, idiopathic double thoracic curve AIS were analyzed retrospectively. Surgery 2010-2019 with pedicle screw double rod systems in a scoliosis center. Follow-up (FU) at least 2 years. Frontal and sagittal angles (whole-spine radiographs, 2 planes): thoracic curve (MK), proximal-thoracic curve (PK) and lumbar curve (LK), thoracic kyphosis (TK), lumbar lordosis (LL).

STATISTICAL ANALYSIS

values as MW ± SD, students t‑test (significance a = 0.05), Pearson's correlation, sub-analysis with sagittal modifiers (-, N, +).

RESULTS

A total of 47 AIS-double thoracic curve were identified, mean FU 29.3 ± 12.2 months, mean age 14 ± 1.5 years. The mean correction (FU-preop) of MK was 67%, PK 53%, LK 73%, each significant, (p < 0.05). On average, TK (FU-preop) decreased by -6.5 ± 11.6° (p < 0.05), no significant change from FU (p = 0.6). TK (FU-preop) increased by 8.6 ± 5.0° (p < 0.05) in hypokyphotic cases, significantly decreased by -4.8 ± 9.6° in normokyphotic AIS and -25.3 ± 11.1° in hyperkyphotic cases, respectively (p < 0.05). In hypokyphosis: moderately strong correlation between correction PK (r = -0.5) and spontaneous correction LK (r = 0.8) (frontal plane) and change from pre- to postop TK (sagittal plane) (p < 0.05). Moderate correlation for hyperkyphosis: correction PK (r = -0.5) and postop TK (p < 0.05). No relevant correlations for normokyphosis. 17% had postop hypokyphosis, of which 0% had preop hypokyphosis. Rod diameter (5.5 mm vs. 6 mm) had no significant effect on TC.

CONCLUSIONS

Posterior instrumented correction and fusion (pedicle screw dual rod systems) can significantly correct both lateral curves in idiopathic double thoracic curves, although it is associated with an increased risk of postop thoracic hypokyphosis, especially in preoperatively normokyphotic patients.

Influence of posterior instrumented correction with pedicle screw dual rod systems on thoracic kyphosis in Lenke 1 and 2 curves: minimum 2 years follow-up

PURPOSE

Adolescent idiopathic scoliosis (AIS) often correspond with hypo thoracic kyphosis (TK) or even lordosis. The aim of this study was to analyze the influence of posterior instrumentation in thoracic AIS.

METHODS

Analysis of prospectively collected AIS-data with structural thoracic curves (Lenke type 1 & 2), operated 2010-2019 with pedicle screw dual rod systems in one scoliosis center. Follow-up (FU) minimum 24 months. Coronal and sagittal angles measured based on standing long-cassette-X-rays: thoracic major (MC), proximal thoracic (PC) and lumbar curve (LC), TK, lumbar lordosis (LL).

STATISTICAL ANALYSIS

values as mean ± SD, differences by student's t-test (significancy a = 0.05), Pearson's correlation, sub-analysis with sagittal modifier (-, N, +).

RESULTS

A total of 127 AIS could be identified (63% type 1, 37% type 2). Mean FU 32.2 ± 16.6 months, mean age 14 ± 1.5 years. Mean Correction of MC 73 ± 12%, PC 51 ± 17%, LC 69 ± 21% with a significantly better correction of PC in Lenke 2 curves(p < 0.05). On average, TK (FU-preop) decreased by -2.1 ± 12.1°(p < 0.05) in all AIS. Whereas TK in type 1 was unchanged (p = 0.9), TK significantly decreased by - 6.0 ± 12.7°(p < 0.05) in type 2. No significant difference in LL. TK in hypokyphotic cases increased by 9.5 ± 5.5°(p < 0.05), stayed almost unchanged (- 1.4 ± 9.1°,p = 0.2) in normokyphotic, decreased by - 17.2 ± 14.2°(p < 0.05) in hyperkyphotic cases. Only hypokyphotic cases had a moderately strong correlation between correction of LC (r = 0.6) and PC (r = - 0.4) (frontal plane) and change from pre- to postoperative TK (sagittal plane) (r = 0.6). No relevant correlations for normo- and hyperkyphotic AIS. Postoperative hypokyphosis was significantly more often in Lenke 2 (16.3% vs. 2.6%, p < 0.05). Rod diameter (5,5 mm versus 6 mm) had no significant influence.

CONCLUSION

Significant correction of hypo- and hyperkyphosis can be achieved with posterior spinal fusion (pedicle screw dual rod systems), whereas normokyphotic spines stay unchanged. However, Lenke 2 curves have a significantly higher risk for a postoperative thoracic hypokyphosis.

Novel AI-Based Algorithm for the Automated Computation of Coronal Parameters in Adolescent Idiopathic Scoliosis Patients: A Validation Study on 100 Preoperative Full Spine X-Rays

STUDY DESIGN

Retrospective, mono-centric cohort research study.

OBJECTIVES

The purpose of this study is to validate a novel artificial intelligence (AI)-based algorithm against human-generated ground truth for radiographic parameters of adolescent idiopathic scoliosis (AIS).

METHODS

An AI-algorithm was developed that is capable of detecting anatomical structures of interest (clavicles, cervical, thoracic, lumbar spine and sacrum) and calculate essential radiographic parameters in AP spine X-rays fully automatically. The evaluated parameters included T1-tilt, clavicle angle (CA), coronal balance (CB), lumbar modifier, and Cobb angles in the proximal thoracic (C-PT), thoracic, and thoracolumbar regions. Measurements from 2 experienced physicians on 100 preoperative AP full spine X-rays of AIS patients were used as ground truth and to evaluate inter-rater and intra-rater reliability. The agreement between human raters and AI was compared by means of single measure Intra-class Correlation Coefficients (ICC; absolute agreement; >.75 rated as excellent), mean error and additional statistical metrics.

RESULTS

The comparison between human raters resulted in excellent ICC values for intra- (range: .97-1) and inter-rater (.85-.99) reliability. The algorithm was able to determine all parameters in 100% of images with excellent ICC values (.78-.98). Consistently with the human raters, ICC values were typically smallest for C-PT (eg, rater 1A vs AI: .78, mean error: 4.7°) and largest for CB (.96, -.5 mm) as well as CA (.98, .2°).

CONCLUSIONS

The AI-algorithm shows excellent reliability and agreement with human raters for coronal parameters in preoperative full spine images. The reliability and speed offered by the AI-algorithm could contribute to the efficient analysis of large datasets (eg, registry studies) and measurements in clinical practice.

Anterior Lumbar Interbody Fusion (ALIF) or Transforaminal Lumbar Interbody Fusion (TLIF) for Fusion Surgery in L5/S1 - What Is the Best Way to Restore a physiological Alignment?

STUDY DESIGN

A retrospective single center cohort study with prospective collected data from an institutional spine registry.

OBJECTIVES

To determine whether restoration of lordosis L5/S1 is possible with both anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) and to find out which technique is superior to recreate lordosis in L5/S1.

METHODS

Seventy-seven patients with ALIF and seventy-nine with TLIF L5/S1 were included. Operation time, estimated blood loss), and complications were evaluated. Segmental lordosis L5/S1 and L4/5, overall lordosis, and proximal lordosis (L1 to L4) were measured in X-rays before and after surgery. Oswesery disability index and EQ-5D were assessed before surgery, and 3 and 12 months after surgery.

RESULTS

Mean operation time was 176.9 minutes for ALIF and 195.7 minutes for TLIF (p = 0.048). Estimated blood loss was 249.2 cc for ALIF and 362.9 cc for TLIF (p = 0.005). In terms of complications, only a difference in dural tears were found (TLIF 6, ALIF none; p = 0.014). Lordosis L5/S1 increased in the ALIF group (15.8 to 24.6°; p < 0.001), whereas no difference was noted in the TLIF group (18.4 to 19.4°; p = 0.360). Clinical results showed significant improvement in the Oswesery disability index (ALIF: 43 to 21.9, TLIF: 45.2 to 23.0) and EQ-5D (ALIF: 0.494 to 0.732, TLIF: 0.393 to 0.764) after 12 months in both groups, without differences between the groups.

CONCLUSION

ALIF and TLIF are comparable methods for performing fusion at L5/S1, with good clinical outcomes and comparable rates of complications. However, there is only a limited potential for recreating lordosis at L5/S1 with a TLIF.

How can postoperative shoulder imbalance be prevented in adolescent idiopathic scoliosis type 2?

Postoperative shoulder imbalance (PSI) is a common complication following adolescent idiopathic scolio- sis (AIS) surgery. There is little data available in literature on prediction of PSI. Prospectively collected data of AIS with thoracic curve (Lenke 2), operated in 2014-2018 at a single scoliosis-center, were analyzed retrospectively using X-rays of whole spine and traction films (TA): age, Cobb-angle of proximal (PC), major thoracic (MC) and lumbar curve (LC), shoulder height [mm], clavicle angle [°], T1-tilt [°], plumb line [mm]. Results as mean ± standard deviation. Change over time (postOP- FU) compared using t-test (≥=0.05). Correlation of preOP parameters and curve correction with PSI (|≥|15mm) was analyzed by correlation (Pearson)- and regression-classification-analysis. 32 AIS, average age of 14±1.3 yrs. FU 16 months (84%). Curve correction was 52.5% (PC), 70.1% (MC), 69.9% (LC), significant change in FU for PC (-2.4°, p>0.05), not for MC, LC (p=0.2, p=0.6). Shoulder height was negative if right- side up: 2.9±15.1mm (preOP), 5.5±15.0 mm (TA), 17.9±14.9mm (postOP), 17.4±8.4mm (FU). 28% had preOP shoulder imbalance, 69% postOP and 44% FU had PSI. Shoulder height on TA correlated to change preOP to FU (r=0.62) and preOP shoulder height (r=-0.85), clavicle angle had strong correlation (r=- 0.81). Regression-classification-analysis: correction of MC>62.4%, 81.5% of cases had PSI; with correction of MC>64.9% and LC>93.2%, 51.9% of cases had PSI. PSI is a common in Lenke2 AIS. In preOP planning TA, shoulder position and clavicle angle should be considered to prevent PSI. Correction of MC should be moderate, overcorrection of the LC avoided.

[What explains the "gendered reputation" of residency subjects? : Reasons for gendered specialty selection and careers in spine-surgery residency programs-compared to a "female" specialty]

BACKGROUND

Currently, the proportion of women in academic education and residency is predominant, but specialty-specific distribution of leading positions is partly reciprocal (orthopedics/surgery). Are there any differences that indicate a gender-dependent redistribution in leadership positions already in the selection of postgraduate training?

METHODS

Online survey with orthopedics/trauma surgery (OUC) and neurosurgery (NCH) residents. Comparison with gynecology (GYN). Statistical analysis, mean in percent, statistical differences using t‑ or chi²-test (significance level α = 0,05).

RESULTS

Returned questionnaire = 277, complete participation = 250. Female residents: OUC:52%, NCH:57%, GYN:85%. A total of 49% were told in medical school that a subject was inappropriate for gender reasons (f57-76%, m10-33%). The most frequent reason for a subject: all = "operating activity". The second most frequent reason: OUC-f = "good working atmosphere", OUC-m = "establishment", NCH-f = "career" and "good working atmosphere", NCH-m = "good working atmosphere", GYN-f = "establishment", GYN-m = "career". The most frequent reason against: OUC/GYN = "hardly any possibility to become established", NCH = "negative leadership style by superiors". For female residents in OUC/NCH, work/family balance had the smallest influence on the choice of specialty. Their subjective evaluation of compatibility was significantly the worst, and overall OUC/NCH was significantly worse than GYN. Although female residents in NCH were more likely to justify the specialty choice based on career goals, male residents in OUC/NCH were more likely to aim for a higher hierarchical position.

DISCUSSION

The results of this study emphasize that disciplines receive a gender-specific conditioning already at the undergraduate level, which has a clear impact on the choice of specialty. The image in this regard needs to be reconsidered, as even surgical subjects will predictably have to rely on more female specialists.

Analysis of Preoperative and Operative Factors Influencing Postoperative Shoulder Imbalance in Lenke Type 1 Adolescent Idiopathic Scoliosis

BACKGROUND

Postoperative shoulder imbalance is a common complication in adolescent idiopathic scoliosis and may impair patient satisfaction. The little data in the literature on the prediction and treatment of postoperative shoulder imbalance is incongruous. According to some studies, postoperative shoulder imbalance depends on the superior instrumented vertebral bodies, skeletal maturity, extent of correction and flexibility of the major curve.

QUESTION

Can preoperative radiological parameters from X-ray and traction films as well as correction of the curves be used to identify a factor impacting on postoperative shoulder imbalance?

MATERIAL AND METHODS

Prospective data in adolescent idiopathic scoliosis with thoracic curve (Lenke type 1), operated on between 2015 and 2018 at a scoliosis centre, were analysed retrospectively based on full-length X-rays of the spine (pre-/postOP and follow-up (FU)) and preoperative-traction films: age; correction of proximal, main and lumbar curve; shoulder height [mm]; clavicle angle [°]; T1 tilt [°]; coronal plumb line deviation [mm]. The findings were expressed as means with standard deviation. Changes in parameters over time (postOP-FU) were compared by t test (significance level α = 0.05). The correlation between preOP parameters and extent of correction with postoperative shoulder imbalance (≥ 15 mm) was determined by Pearson correlation and regression classification analysis.

OUTCOMES

55 patients with adolescent idiopathic scoliosis, mean age of 15 ± 1.4 years. The FU-rate after a mean of 15 months was 80% (n = 44). Correction of proximal, main and lumbar curve: 47.0%, 75.8% and 68.8%, respectively, without statistically significant change (Δ) in FU (p > 0.05). Shoulder height was - 11.0 ± 12.7 mm (preOP), 15.5 ± 13.4 mm (postOP), 10.1 ± 10.6 mm (FU) (p < 0.05). 38% of those with adolescent idiopathic scoliosis had preOP right shoulder elevation; 55% (postOP) and 32% (FU) respectively had postoperative shoulder imbalance (left shoulder elevation). Strong statistical correlation was found for Δshoulder position (FU-preOP) with pre-OP shoulder position (r = - 0.7), and Δshoulder position (pre-OP traction films) (r = 0.5) with pre-OP clavicle angle (r = - 0.5). On regression classification analysis, 81.8% of cases did display postoperative shoulder imbalance if proximal curve correction was ≤ 64.4%; main and lumbar curve correction, Δshoulder elevation (preOP traction films) played a secondary role.

DISCUSSION

One common complication even in Lenke type 1 adolescent idiopathic scoliosis is postoperative shoulder imbalance. Preoperative planning should include traction films, preoperative shoulder position and clavicle angle to avoid postoperative shoulder imbalance. Moderate correction of proximal curve is critical for postoperative shoulder balance.

Intraoperative Radiation Exposure for Patients with Double-Curve Idiopathic Scoliosis in Freehand-Technique in Comparison to Fluoroscopic- and CT-Based Navigation

BACKGROUND

In the operative treatment of idiopathic scoliosis, posterior correction and fusion in freehand technique is a proven procedure and is frequently performed. Malpositioned pedicle screws can result in serious neurovascular complications. Intraoperative fluoroscopy and neurophysiological measurements are performed to ensure the correct position of pedicle screws. Newer procedures with fluoroscopic- and computertomographic-assisted navigation are advertised as less dangerous and with a more accurate screw position.

HYPOTHESIS

Is the freehand technique used in the surgical treatment of idiopathic scoliosis safer than other methods with regard to complications caused by screw malposition and intraoperative radiation exposure?

MATERIAL AND METHODS

Register data of 34 consecutive idiopathic scoliosis patients with two structural curves (Lenke 3 and 6) were collected prospectively in our scoliosis center and were retrospectively analyzed. The following parameters were evaluated: total radiation product, time of fluoroscopy, number of fused segments, time of operation, blood loss, screw-related complications and number of instrumented pedicle screws. All values were given as mean ± standard deviation and statistically analyzed. Finally, our data were compared on accuracy of screw placement and radiation exposure to data from literature with screw placement under navigation.

RESULTS

Average age at the time of surgery was 23.6 ± 12 years. The average thoracic curve was 69.2 ± 14.2° preoperatively and 21.7 ± 12.8° postoperatively (correction 69.9%), the average lumbar curve was 64.3° ± 10.8° preoperatively and corrected to 15.6 ± 10.4° postoperatively (correction 76.2%). The total radiation product per patient was 145.7 ± 86.1 cGy*cm², the time of fluoroscopy 31.7 ± 23.5 s (11.5 segments), the time of operation 267.2 ± 64.1 min and the blood loss 700.4 ± 522.3 ml. A total of 803 pedicle screws were placed. No screw-associated complications were detected in the entire collective. The comparison of our data with freehand placement of pedicle screws to literature data showed a noticeable higher radiation exposure for the patient during fluoroscopic- and computertomographic-assisted navigation.

DISCUSSION

The results showed that positioning of pedicle screws with freehand technique in patients with idiopathic scoliosis is accompanied with considerably lower intraoperative radiation exposure compared to fluoroscopic- or computertomographic-assisted navigation. An increased radiation exposure of these typically young patients is associated with an increased long-term risk for the occurrence of radiation-induced malignant diseases. With appropriate surgical experience, placement of pedicle screws in freehand technique is safe and effective and with similar accuracy than screws placed under navigation, but produces significantly less radiation exposure to the patients.

[Collected data on freehand technique instrumentation and literature comparison on fluoroscopic and CT-assisted navigation]

BACKGROUND

A proven and frequently used surgical procedure in patients with idiopathic scoliosis (IS) is posterior transpedicular corrective spondylodesis using the freehand technique. Novel procedures with fluoroscopically and computed tomography (CT)-assisted navigation are presumed to be less risky and more accurate.

OBJECTIVE

Is the freehand technique for IS safe with respect to screw-associated complications and intraoperative radiation exposure?

MATERIAL AND METHODS

Prospectively collected data (2017-2018) from 39 consecutive patients (average age 18.7 years) with thoracic single curvature IS (61.7° ± 13.9°) from a specialized scoliosis center were evaluated for the following parameters (mean ± standard deviation): total radiation product, fluoroscopy time, fused segments, operative time, blood loss and screw-associated complications. A comparison with data from the literature on intraoperative radiation exposure using navigation procedures was carried out.

RESULTS

The total radiation product per patient was 71.7 ± 44.0 cGy*cm², fluoroscopy time 17.4 ± 8.6 s. (7.8 segments), operative time 183.5 ± 54.2 min and blood loss 379.5 ± 183 ml. There were no screw-associated complications in the entire collective. Correction of the main curvature was 75.7%. Comparison of the data with index data from the literature showed a 1.25-12.5-fold higher radiation exposure for patients with fluoroscopically assisted navigation and 9.25-12.3-fold higher radiation exposure with CT-assisted procedures compared to the present results.

CONCLUSION

The results of this study showed that with appropriate experience freehand positioning of pedicle screws is associated with comparable accuracy and less radiation exposure for patients than navigation procedures. With respect to the young age of patients, a radiation-induced long-term risk for malignant diseases should be taken into consideration.

Comparison of 4D Flow MRI to 2D Flow MRI in the pulmonary arteries in healthy volunteers and patients with pulmonary hypertension

Purpose

4D and 2D phase-contrast MRI (2D Flow MRI, 4D Flow MRI, respectively) are increasingly being used to noninvasively assess pulmonary hypertension (PH). The goals of this study were i) to evaluate whether established quantitative parameters in 2D Flow MRI associated with pulmonary hypertension can be assessed using 4D Flow MRI; ii) to compare results from 4D Flow MRI on a digital broadband 3T MR system with data from clinically established MRI-techniques as well as conservation of mass analysis and phantom correction and iii) to elaborate on the added value of secondary flow patterns in detecting PH.

Methods

11 patients with PH (4f, 63 ± 16y), 15 age-matched healthy volunteers (9f, 56 ± 11y), and 20 young healthy volunteers (13f, 23 ± 2y) were scanned on a 3T MR scanner (Philips Ingenia). Subjects were examined with a 4D Flow, a 2D Flow and a bSSFP sequence. For extrinsic comparison, quantitative parameters measured with 4D Flow MRI were compared to i) a static phantom, ii) 2D Flow acquisitions and iii) stroke volume derived from a bSSFP sequence. For intrinsic comparison conservation of mass-analysis was employed. Dedicated software was used to extract various flow, velocity, and anatomical parameters. Visualization of blood flow was performed to detect secondary flow patterns.

Results

Overall, there was good agreement between all techniques, 4D Flow results revealed a considerable spread. Data improved after phantom correction. Both 4D and 2D Flow MRI revealed concordant results to differentiate patients from healthy individuals, especially based on values derived from anatomical parameters. The visualization of a vortex, indicating the presence of PH was achieved in 9 /11 patients and 2/35 volunteers.

Discussion

This study confirms that quantitative parameters used for characterizing pulmonary hypertension can be gathered using 4D Flow MRI within clinically reasonable limits of agreement. Despite its unfavorable spatial and lesser temporal resolution and a non-neglible spread of results, the identification of diseased study participants was possible.

Mapping the HLA ligandome landscape of acute myeloid leukemia: a targeted approach toward peptide-based immunotherapy

Identification of physiologically relevant peptide vaccine targets calls for the direct analysis of the entirety of naturally presented human leukocyte antigen (HLA) ligands, termed the HLA ligandome. In this study, we implemented this direct approach using immunoprecipitation and mass spectrometry to define acute myeloid leukemia (AML)-associated peptide vaccine targets. Mapping the HLA class I ligandomes of 15 AML patients and 35 healthy controls, more than 25 000 different naturally presented HLA ligands were identified. Target prioritization based on AML exclusivity and high presentation frequency in the AML cohort identified a panel of 132 LiTAAs (ligandome-derived tumor-associated antigens), and 341 corresponding HLA ligands (LiTAPs (ligandome-derived tumor-associated peptides)) represented subset independently in >20% of AML patients. Functional characterization of LiTAPs by interferon-γ ELISPOT (Enzyme-Linked ImmunoSpot) and intracellular cytokine staining confirmed AML-specific CD8(+) T-cell recognition. Of note, our platform identified HLA ligands representing several established AML-associated antigens (e.g. NPM1, MAGED1, PRTN3, MPO, WT1), but found 80% of them to be also represented in healthy control samples. Mapping of HLA class II ligandomes provided additional CD4(+) T-cell epitopes and potentially synergistic embedded HLA ligands, allowing for complementation of a multipeptide vaccine for the immunotherapy of AML.

The architectural transition of human complement component C9 to poly(C9)

Several regions of C9 including three cysteine-rich modules homologous to those in thrombospondin (TS), the low density lipoprotein receptor (LDL), the epidermal growth factors (EDGF), as well as two middle sections of the polypeptide chain were expressed in bacteria. Antibodies derived from these segments were used to probe the relative exposure of epitopes in C9 and poly(C9) using ELISAs. The results indicated that the TS and LDL modules are fully exposed in both monomer and polymer; however, the middle region of the polypeptide chain is buried in the monomer but external in the polymer. Using specified conditions, Fab fragments to the TS and LDL modules did not block C9 polymerization, but those to the middle region of the polypeptide chain and to some extent to the EDGF module did so. Immuno-electron microscopy of poly(C9) indicated that the C9 polypeptide chain assumes a 'U' shape, in which the TS and LDL modules are located on the upper rim. The EDGF module is located on the lower edge of the upper rim, and midsection of the polypeptide chain constructs the barrel of the tubule. Computer assisted contrast enhancement of select electron micrograph images of poly(C9) allowed the clear visualization of each subunit. These were seen to have a volute shape. The upper rim is composed of whorls that are apparently not in lateral contact. It is concluded that the TS and LDL modules do not participate directly in polymerization but cover the hydrophobic central region of the polypeptide chain in the monomer. As a consequence of circular polymerization the midsection of the polypeptide chain becomes exposed as each C9 lengths to fashion a volute form. reserved.

The efficacy and safety of miglitol therapy compared with glibenclamide in patients with NIDDM inadequately controlled by diet alone

OBJECTIVE

To compare the therapeutic effects of the alpha-glucosidase inhibitor miglitol (BAY m 1099), the sulfonylurea glibenclamide, and placebo on parameters of metabolic control and safety in patients with NIDDM that is inadequately controlled by diet alone.

RESEARCH DESIGN AND METHODS

After a 4-week placebo run-in period, 201 patients in 18 centers in 4 countries were randomized in a double-blind manner to miglitol (50 mg t.i.d., followed by 100 mg t.i.d.), glibenclamide (3.5 mg q.d/b.i.d.), or placebo for 24 weeks. Efficacy criteria were changes from baseline of HbA1c, fasting and postprandial blood glucose and insulin levels, body weight, and serum triglycerides.

RESULTS

Efficacy was assessed in 119 patients who completed the full protocol, and the results were similar to those obtained in 186 patients who fulfilled the validity criteria for analysis. Compared with placebo, mean baseline-adjusted HbA1c decreased by 0.75% (P = 0.0021) and 1.01% (P = 0.0001) in the miglitol and glibenclamide treatment groups, respectively. Blood glucose decreased slightly in the fasting state and considerably in the postprandial state in both treatment groups but not in the placebo group. Fasting insulin levels increased slightly (NS) in all treatment groups; however, postprandial insulin levels decreased with miglitol, while increasing markedly with glibenclamide (P = 0.0001 between all treatment groups). Gastrointestinal side effects (flatulence and diarrhea) occurred mostly in the miglitol-treated patients, while some glibenclamide-treated patients had symptoms suggestive of hypoglycemia.

CONCLUSIONS

Miglitol monotherapy is effective and safe in NIDDM patients. Compared with glibenclamide, it reduced HbA1c less effectively and caused more gastrointestinal side effects. On the other hand, glibenclamide, unlike miglitol, tended to cause hypoglycemia, hyperinsulinemia, and weight gain, which are not desirable in patients with NIDDM.

N-methyl-D-aspartate antagonists limit aminoglycoside antibiotic-induced hearing loss

The use of aminoglycoside antibiotics is limited by ototoxicity that can produce permanent hearing loss. We report that concurrent administration of N-methyl-D-aspartate (NMDA) antagonists markedly attenuates both the hearing loss and destruction of cochlear hair cells in guinea pigs treated with aminoglycoside antibiotics. These findings indicate that aminoglycoside-induced hearing loss is mediated, in part, through an excitotoxic process. The high correlation (Spearman correlation coefficient: 0.928; P < 0.01) obtained between the relative cochleotoxicities of a series of aminoglycosides in humans and the potencies of these compounds to produce a polyamine-like enhancement of [3H]dizocilpine binding to NMDA receptors is consistent with this hypothesis, and provides a simple in vitro assay that can predict this aspect of aminoglycoside-induced ototoxicity.

A continuous microtiter plate assay for screening nucleotide sugar-synthesizing nucleotidyltransferases

A continuous microtiter plate nucleotidyltransferase substrate screening assay (NUSSA) is described which allows the identification of nucleotide sugar-synthesizing enzyme activities. The assay is accomplished by the determination of the common product of these enzymes PPi with a PPi-dependent phosphofructokinase. A subsequent enzyme reaction cascade leads to the production of 2 mol NAD per mol PPi. PPi-dependent phosphofructokinase was purified from potato with respect to contaminating enzyme activities which would disturb NUSSA performance. NUSSA allows the quick, simultaneous, and comprehensive check of different sugar 1-phosphate and nucleoside triphosphate substrates using purified pyrophosphorylases or crude extracts of plants, microorganisms, and mammalian tissues. Moreover, NUSSA will assist to evaluate these enzymes for the synthesis of important nucleotide sugars which serve as substrates of glycosyltransferases in carbohydrate syntheses.

alpha 4 integrins mediate lymphocyte attachment and rolling under physiologic flow

Of the several families of adhesion receptors involved in leukocyte-endothelial cell interactions, only the selectins have been shown to initiate leukocyte interaction under physiologic shear; indeed, beta 2 (CD18) intergrins responsible for neutrophil arrest are unable to engage without prior selectin-mediated rolling. In contrast, alpha 4 (CD49d) integrins are shown here to initiate lymphocyte contract ("tethering") in vitro under shear and in the absence of a selectin contribution. The alpha 4 integrin ligands MAdCAM-1 and VCAM-1 support loose reversible interactions including rolling, as well as rapid sticking and arrest that is favored following integrin activation. Moreover, alpha 4 beta 7 mediates L-selectin (CD62L)-independent attachment of blood-borne lymphocytes to lamina propria venules in situ. Scanning electron microscopy of alpha 4 beta 7hi lymphoid cells reveals that, like L-selectin, alpha 4 beta 7 is highly concentrated on microvillous sites of initial cellular contact, whereas the beta 2 integrin LFA-1 is excluded from villi. Thus, alpha 4 but not beta 2 integrins can initiate leukocyte adhesion under flow, a capacity that may be in part a function of topographic presentation on microvilli.

Distinct but overlapping epitopes are involved in alpha 4 beta 7-mediated adhesion to vascular cell adhesion molecule-1, mucosal addressin-1, fibronectin, and lymphocyte aggregation

The mouse CD8+ T cell lymphoma TK1 expresses high levels of alpha 4 beta 7 integrin, which it can use to interact with multiple ligands including mucosal addressin-1 (MAdCAM-1), VCAM-1, and fibronectin. In addition, alpha 4 beta 7 can support TK1 cell aggregation. Here we have produced and characterized a panel of mAbs against alpha 4 beta 7 to define antigenic and functional epitopes associated with its distinct functions. One mAb, DATK32, is unique in recognizing an epitope specific to the alpha 4 beta 7 heterodimer. Furthermore, DATK32 induces TK1 cell aggregation yet inhibits TK1 cell adhesion to MAdCAM-1, VCAM-1, and fibronectin. Considered as a whole, the panel of anti-alpha 4 beta 7 mAbs studied define unique patterns of inhibition for alpha 4 beta 7 binding to each of its defined molecular ligands. We conclude that alpha 4 beta 7 interactions with MAdCAM-1, VCAM-1, and fibronectin can be modulated by Ab binding to distinct epitopes and thus probably involve functionally separable, although physically overlapping binding sites on this multifunctional integrin. These findings are consistent with the general observation that integrins use distinct, potentially differentially regulated interaction sites for adhesion to multiple ligands. Extension of these concepts to alpha 4 beta 7 has important considerations for understanding the roles of this integrin in lymphocyte homing to mucosal sites and in cell-cell interactions during the immune response.

Distinct but overlapping epitopes are involved in alpha 4 beta 7-mediated adhesion to vascular cell adhesion molecule-1, mucosal addressin-1, fibronectin, and lymphocyte aggregation

The mouse CD8+ T cell lymphoma TK1 expresses high levels of alpha 4 beta 7 integrin, which it can use to interact with multiple ligands including mucosal addressin-1 (MAdCAM-1), VCAM-1, and fibronectin. In addition, alpha 4 beta 7 can support TK1 cell aggregation. Here we have produced and characterized a panel of mAbs against alpha 4 beta 7 to define antigenic and functional epitopes associated with its distinct functions. One mAb, DATK32, is unique in recognizing an epitope specific to the alpha 4 beta 7 heterodimer. Furthermore, DATK32 induces TK1 cell aggregation yet inhibits TK1 cell adhesion to MAdCAM-1, VCAM-1, and fibronectin. Considered as a whole, the panel of anti-alpha 4 beta 7 mAbs studied define unique patterns of inhibition for alpha 4 beta 7 binding to each of its defined molecular ligands. We conclude that alpha 4 beta 7 interactions with MAdCAM-1, VCAM-1, and fibronectin can be modulated by Ab binding to distinct epitopes and thus probably involve functionally separable, although physically overlapping binding sites on this multifunctional integrin. These findings are consistent with the general observation that integrins use distinct, potentially differentially regulated interaction sites for adhesion to multiple ligands. Extension of these concepts to alpha 4 beta 7 has important considerations for understanding the roles of this integrin in lymphocyte homing to mucosal sites and in cell-cell interactions during the immune response.

L-selectin-mediated lymphocyte rolling on MAdCAM-1

The L-selectin, a cell surface C-type lectin, directs lymphocyte traffic to lymph nodes, and contributes to lymphocyte homing to Peyer's patches and to leukocyte interactions with inflamed venules. Here we report that the mucosal vascular addressin MAdCAM-1, a mucosal endothelial adhesion molecule with immunoglobulin- and mucin-like domains, is a facultative ligand for L-selectin. MAdCAM-1 isolated from mesenteric lymph nodes, but not from cultured endothelioma cells, bears N-glycanase-resistant sialic acid-containing carbohydrate which supports adhesion of L-selectin-transfected lymphoid cells under shear. Interacting lymphoid cells display a 'rolling' behaviour similar to the selectin-dependent rolling of neutrophils observed in inflamed venules. MAdCAM-1 is also a ligand for the lymphocyte integrin homing receptor for Peyer's patches, alpha 4 beta 7 (ref. 7), and may be uniquely adapted to support both selectin-mediated lymphocyte rolling and integrin-mediated adhesion and arrest in vivo.

Alpha 4 beta 7 integrin mediates lymphocyte binding to the mucosal vascular addressin MAdCAM-1

The mucosal vascular addressin, MAdCAM-1, is an immunoglobulin superfamily adhesion molecule for lymphocytes that is expressed by mucosal venules and helps direct lymphocyte traffic into Peyer's patches (PP) and the intestinal lamina propria. We demonstrate that the lymphocyte integrin alpha 4 beta 7, also implicated in homing to PP, is a receptor for MAdCAM-1. Certain antibodies to alpha 4 and beta 7 integrin chains but not to the beta 2 integrin LFA-1 inhibit lymphocyte binding to purified MAdCAM-1 and to MAdCAM-1 transfectants. Lymph node lymphocytes, alpha 4 beta 7+ TK1 lymphoma cells, and a beta 7-transfected variant of an alpha 4+ B cell line, 38C13, bind constitutively to MAdCAM-1. Binding is enhanced by Mn(++)-induced integrin activation. The related integrin alpha 4 beta 1 supports efficient binding to VCAM-1 but not to MAdCAM-1, even after integrin activation, indicating that MAdCAM-1 is a preferential ligand for alpha 4 beta 7. Alpha 4 beta 7 can also bind VCAM-1, but this requires greater integrin activation than binding to MAdCAM-1. The findings imply a selective role for the interaction of alpha 4 beta 7 and MAdCAM-1 lymphocyte in homing to mucosal sites.

Lymphocyte activation and regulation of three adhesion molecules with supposed function in homing: LECAM-1 (MEL-14 antigen), LPAM-1/2 (alpha 4-integrin) and CD44 (Pgp-1)

Directed migration of lymphocytes from blood into lymph nodes and gut-associated lymphatic tissue, also referred to as homing, is subject to change following activation. Lymphocyte migration into lymphoid organs in vivo and binding to high endothelial venules in vitro is largely suppressed after short-term stimulation with phorbol esters. The observed functional alterations were correlated with changes in the expression of three putative homing receptors, LECAM-1 (MEL-14 antigen), LPAM-1/2 (alpha 4-integrin) and the murine CD44 (Pgp-1, H-CAM, Hermes-antigen equivalent) upon different modes of cellular activation. Expression of LECAM-1 (gp90 MEL-14), a lymphocyte adhesion molecule implicated in targeting extravasation into lymph nodes, was found to be lost almost completely within minutes after protein kinase C activation. LECAM-1 re-expression occurred within less than 24 h. Rapid loss of LECAM-1 was also observed after calcium ionophores whereas anti-CD3 or concanavalin A elicited a gradual and heterogeneous loss of LECAM-1 becoming detectable after several hours only. A number of cytokines tested were not able to induce alterations in LECAM-1 expression. In contrast, expression of LPAM-1/2 (alpha 4-integrin) and CD44 (Pgp-1, H-CAM), two adhesion molecules supposed to direct extravasation into Peyer's patches, remained stable for hours after every stimulus tested; CD44 expression gradually increased 24 h after mitogenic activation, whereas a small reduction only was observed for the expression of the alpha 4-chain under certain conditions. Thus, reduced extravasation of lymphocytes into Peyer's patches after activation is not due to a decline in the surface density of LPAM-1/2 alpha-chain or CD44 whereas alterations in migration into lymph nodes parallel the expression of LECAM-1.

Lymphocyte activation and expression of the human leucocyte-endothelial cell adhesion molecule 1 (Leu-8/TQ1 antigen)

The Leu-8/TQ1 antigen, recently shown to be the human equivalent of the murine MEL-14 lymph node homing receptor and now designated as leucocyte-endothelial cell adhesion molecule, LECAM-1, has been used to dissect T, B and natural killer (NK) cells into various subpopulations with different functional properties, such as suppressor-inducer (CD4+ Leu-8/TQ1+) or helper (CD4+ Leu-8/TQ1-) T lymphocytes. Diminished Leu-8/TQ1 antigen density has been reported after lymphocyte activation with B- or T-cell specific stimuli for several days. In the present study, we sought to determine the signal requirements for altered Leu-8/TQ1 expression. Exposure of freshly isolated peripheral blood lymphocytes to phorbol 12-myristate 13-acetate (PMA) and/or calcium ionophores was found to cause rapid down-regulation of the Leu-8 antigen, with little or no Leu-8 reactivity remaining 1 hr after simultaneous addition of PMA and calcium ionophores to the culture medium. TQ1 reactivity was changed in parallel with that of Leu-8. Leu-8 expression of T and B cells was sensitive to both PMA and calcium ionophores, whereas Leu-8 expression of NK cells was affected by PMA but not by the calcium ionophore A23187. The effect of PMA on Leu-8/TQ1 expression could be antagonized by pretreatment with the protein kinase C inhibitor, H7, whereas that of A23187 could not. Partial re-expression of the Leu-8 antigen was seen 3 days after addition of PMA alone but not when it was given together with calcium ionophores. After Leu-8 down-regulation induced by 1 hr treatment with PMA or calcium ionophores. Leu-8 re-expression was observed within 24 hr when stimuli were removed by washing. Activation of T cells with anti-CD3 antibody resulted in a partial reduction of Leu-8/TQ1 expression, first detectable after 1-3 hr of stimulation and maximal at 24 hr. Fully mitogenmic concentrations of concanavalin A (Con A) did not affect Leu-8 expression within the first hours of culture. Transient reduction of Leu-8 expression was seen 24 hr after supraoptimal dosages of Con A, but Con A-stimulated lymphocytes cultured for 4-12 days with interleukin-2 (IL-2) retained Leu-8/TQ1 reactivity to a similar degree as fresh cells. In contrast to Leu-8/TQ1, CD45RA expression was not altered after 1 hr treatment with PMA and/or calcium ionophores but gradually disappeared during 1 week after Con A stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Reactive perforating collagenosis and phototraumatism

Two pairs of siblings are reported suffering from reactive perforating collagenosis. The clinical features were recurrent crusted papules with a central keratinaceous plug. The plug was sometimes encircled by a narrow yellowish ring and a wider red ring, giving the appearance of a cockade. Lesions recurred spontaneously or were provoked by superficial injury to sun-exposed skin (phototraumatism). There were no other changes in the general health of these patients.

Fluorometric assay of bethanidine in plasma

A fluorometric method for determining bethanidine in blood plasma is described. The bethanidine is extracted into chloroform, a drug-dye complex with eosin Y is formed, and the fluorescence is measured (excitation, 535 nm; fluorescence, 560 nm). The assay detects 0.02 muM bethanidine (4 ng/ml) in plasma. The relative fluorescence of several body constituents and antihypertensive drugs is negligible. The plasma levels of bethanidine in four hypertensive patients receiving this drug were measured.

Diabetic scleredema

A special form of scleredema, confined to adults with severe and complicated diabetes mellitus, has come to be recognized. It lasts for an indefinite period of time, without tendency to spontaneous remission. The name diabetic scleredema is proposed for this form. Two such patients are presented and the literature on the subject is reviewed. We believe that diabetic scleredema should be added to the list of conditions complicating or in any way associated with diabetes mellitus.