The IL-6 receptor antagonist SANT-7 overcomes bone marrow stromal cell-mediated drug resistance of multiple myeloma cells

The bone marrow micro-environment produces a number of different survival factors that are important for the malignant growth and drug resistance of multiple myeloma (MM) cells. One of the main factors reported to be essential for survival and growth of MM cells in some experimental systems is IL-6. Therefore, the development and testing of substances that interfere with IL-6 or IL-6 receptor (IL-6R) function might have therapeutic value for the treatment of MM. We analyzed the effect of the IL-6R antagonist SANT-7 on growth and survival of the IL-6--dependent MM cell lines INA-6 and XG-1 as well as primary MM cells from 7 patients co-cultured with bone marrow stromal cells (BMSCs). In particular, we were interested in whether SANT-7 enhances the growth-inhibitory effects of dexamethasone (Dex) and all-trans-retinoic acid (ATRA). None of the drugs when tested as a single substance, including SANT-7, induced major growth inhibition if MM cells were co-cultured with primary human BMSCs. However, when Dex and ATRA were given in combination with SANT-7, strong growth inhibition was achieved in cell lines and primary MM cells. This effect was due to cell-cycle arrest and induction of apoptosis.

Somatostatin: a new therapeutic option for the treatment of chylothorax

BACKGROUND

The standard treatment of chylothorax in pediatric intensive care today includes conservative therapy with fat-free nutrition, total parenteral nutrition and, if this is not successful, operative treatment (pleurodesis, ligation of the duct, pleuroperitoneal shunt).

PATIENTS

We describe four patients who were not in a suitable condition for operative treatment and who were treated with continuous infusion of somatostatin.

RESULTS

In three patients, chylothorax ceased with the continuous somatostatin infusion without side effects. One patient was treated without success.

CONCLUSIONS

Somatostatin is a therapeutic option for treatment of chylothorax and could reduce surgical intervention and hospitalization time, as well as allow earlier enteral feeding.

Survey of children supported by long-term mechanical ventilation in Switzerland

OBJECTIVE

The aim of the present study was to identify the number of children, from birth to 16 years of age, on long-term mechanical ventilation in Switzerland, and to establish their current location, underlying diagnoses and ventilatory needs.

METHODS

Postal questionnaires were sent to all chest physicians (pulmonologists), intensive care specialists, neurologists, national health care organisations, rehabilitation services and ventilator suppliers known or thought to be involved in paediatric long-term ventilation in Switzerland.

RESULTS

Detailed information was obtained on 32 children from 7 centers. Underlying disorders included congenital central hypoventilation syndrome (CCHS, 41%), neuromuscular disorders (41%), spinal cord injury (6%), craniofacial anomalies (6%) and others (6%). 10 children received positive pressure ventilation by tracheostomy and 19 children by nasal mask. Two children were ventilated by phrenic nerve pacing and one child with the help of a pneumatic belt. Children with CCHS were almost equally divided into nasal mask and tracheostomy users. Ventilation for 16-24 hours a day was necessary in 5 children, exclusively during sleep in 24 children and only episodically in 3 children. All but 2 children were cared for at home. The majority of families received home care support. The most common reasons for readmission into hospital were regular follow-up examinations and respiratory tract infections. The children were mainly admitted to paediatric intensive care units.

CONCLUSIONS

There are few ventilator-supported children in Switzerland and most of them are cared for at home. Nevertheless, there is a need to establish a system for continuing data collection in this particular patient population to assess outcome and quality of home care support and to follow incidence trends.

Survey of children supported by long-term mechanical ventilation in Switzerland

OBJECTIVE

The aim of the present study was to identify the number of children, from birth to 16 years of age, on long-term mechanical ventilation in Switzerland, and to establish their current location, underlying diagnoses and ventilatory needs.

METHODS

Postal questionnaires were sent to all chest physicians (pulmonologists), intensive care specialists, neurologists, national health care organisations, rehabilitation services and ventilator suppliers known or thought to be involved in paediatric long-term ventilation in Switzerland.

RESULTS

Detailed information was obtained on 32 children from 7 centers. Underlying disorders included congenital central hypoventilation syndrome (CCHS, 41%), neuromuscular disorders (41%), spinal cord injury (6%), craniofacial anomalies (6%) and others (6%). 10 children received positive pressure ventilation by tracheostomy and 19 children by nasal mask. Two children were ventilated by phrenic nerve pacing and one child with the help of a pneumatic belt. Children with CCHS were almost equally divided into nasal mask and tracheostomy users. Ventilation for 16-24 hours a day was necessary in 5 children, exclusively during sleep in 24 children and only episodically in 3 children. All but 2 children were cared for at home. The majority of families received home care support. The most common reasons for readmission into hospital were regular follow-up examinations and respiratory tract infections. The children were mainly admitted to paediatric intensive care units.

CONCLUSIONS

There are few ventilator-supported children in Switzerland and most of them are cared for at home. Nevertheless, there is a need to establish a system for continuing data collection in this particular patient population to assess outcome and quality of home care support and to follow incidence trends.

Diagnosing dural metastases: the value of 1H magnetic resonance spectroscopy

The purpose of this study was to assess the value of MRI, MR spectroscopy (MRS) and intra-arterial angiography in the preoperative diagnosis of extra-axial dural-based masses. We prospectively studied 54 patients who underwent preoperative MRI, MRS and angiography. Histologically there were 50 meningiomas and four dural metastases. MRI and angiography did not allow reliable differentiation between meningiomas and metastases. MRS showed elevated choline/creatine ratios in both meningiomas and metastases, but there were prominent lipid signals in all metastases and a lactate peak in two. This spectroscopic pattern was not found in meningiomas. However, following embolisation, they showed similar spectra, due to ischaemia and necrosis. We therefore believe MRS to be valuable in differential diagnosis of dural metastases and meningiomas prior to embolisation.

The release of antidiuretic hormone is appropriate in response to hypovolemia and/or sodium administration in children with severe head injury: a trial of lactated Ringer's solution versus hypertonic saline

We conducted an open, randomized, and prospective study to determine the effect of hypertonic saline on the secretion of antidiuretic hormone (ADH) and aldosterone in children with severe head injury (Glasgow coma scale <8). Thirty-one consecutive patients at a level III pediatric intensive care unit at a children's hospital received either lactated Ringer's solution (Ringer's group, n = 16) or hypertonic saline (Hypertonic Saline group, n = 15) over a 3-day period. Serum ADH levels were significantly larger in the Hypertonic Saline group as compared with the Ringer's group (P = 0.001; analysis of variance) and were correlated to sodium intake (Ringer's group: r = 0.39, R(2) = 0.15, P = 0.02; Hypertonic Saline group: r = 0.42, R(2) = 0.18, P = 0.02) and volume of fluids given IV (Ringer's group: r = 0.38, R(2) = 0.15, P = 0.02; Hypertonic Saline group: r = 0.32, R(2) = 0.1, P = not significant). Correlation of ADH to plasma osmolality was significant if plasma osmolality was >280 mOsm/kg (r = 0.5, R(2) = 0.25, P = 0.06), indicating an osmotic threshold for ADH release. Serum aldosterone levels were larger on the first day than during Days 2 and 3 in both groups and inversely correlated to serum sodium levels only in the Ringer's group (r = -0.55, R(2) = 0.3, P < 0.001). This group received a significantly larger fluid volume on Day 1 (P = 0.05, Mann-Whitney U-test) than did patients in the Hypertonic Saline group, indicating hypovolemia during the first day. Head-injured children have appropriate levels of ADH. They may be hypovolemic during the first day of treatment, especially if they receive lactated Ringer's solution.

IMPLICATIONS

In head-injured patients, we recommend fluid restriction to avoid inappropriate secretion of antidiuretic hormone. In a prospective, randomized, and controlled study in 31 children, we were able to show that the antidiuretic hormone levels are appropriate in response to hypovolemia, sodium load, or both.

Immune reactions of CD4- and CD8-positive T cell subpopulations in spleen and lymph nodes of guinea pigs after vaccination with Bacillus Calmette Guerin

Vaccination of guinea pigs with Mycobacterium bovis BCG confers partial resistance against infection with Mycobacterium tuberculosis. Induction of immunity is associated with a strong T cell response. The reactions of the cytotoxic and helper T lymphocyte subsets after BCG vaccination were analyzed by cytofluorometry and in functional tests. The relative number of CD8(+) T cells in the spleen increased substantially after injection of BCG. In vitro restimulation after immunization induced a strong proliferative response but no cytotoxic reactions of CD8(+) T cells against BCG-infected macrophages. A specific induction of IFN-gamma and RANTES mRNA was observed after vaccination particularly in CD8(+) but not in CD4(+) T cells of the lymph nodes.

HMSC: simultaneously detected heteronuclear shift correlation through multiple and single bonds

A new 2D pulse sequence HMSC (heteronuclear multiple-bond and single-bond coupling connectivities) for the simultaneous detection of long-range and one-bond heteronuclear connectivities is proposed which allows the two types of responses to be separated and the corresponding (n)J(CH) and (1)J(CH) connectivity maps to be calculated. (n)J(CH) coherences are selectively labeled in the course of the pulse sequence, the correspondingly acquired data are separately stored, and a simple add/subtract procedure is applied to disentangle and edit (n)J(CH) and (1)J(CH) responses prior to final data processing. Unlike standard methods, which are designed to measure one single type of heteronuclear spin-spin interactions and to efficiently suppress the other, both (n)J(CH) and (1)J(CH) are measured simultaneously in a single experiment with the HMSC pulse sequence. Compared to the common strategy with two standard experiments applied one after the other, e.g., HMBC and HMQC, valuable measuring time may be saved with this single experiment approach. The efficiency of the new pulse sequence and the quality of the corresponding spectra are demonstrated using strychnine. Features such as sensitivity, lineshapes, and the suppression of (1)J(CH) residual peaks in the final (n)J(CH) subspectra are investigated and compared with the corresponding results obtained with standard methods. The attractive and unique single experiment approach, its high efficiency, and its easy experimental setup together with straightforward data processing make HMSC a valuable experimental alternative for the today's more time-consuming "two-step" practice and makes it suitable for standard routine applications.

Complement activation by recombinant adenoviruses

Recombinant adenoviruses are currently the most important vector system in gene therapy. Adenoviruses frequently cause upper respiratory tract infections in humans and anti-adenoviral antibodies are found in 35-70% of the population. Therefore in the majority of potential patients receiving adenoviral gene therapy, the contact of virus particles and blood will lead to the formation of antigen-antibody complexes. These complexes have the ability to induce inflammatory reactions via an activation of the complement system. We have determined the level of C3a (the most reactive complement component) generated in isolated citrate plasma of healthy individuals after challenge with recombinant and wild-type adenoviruses in amounts corresponding to virus blood levels to be expected in patients during adenoviral gene therapy. All plasma samples containing anti-adenoviral antibodies showed a substantial, dose-dependent generation of C3a. A virus plasma level of about 7.5 x 10(9) particles/ml (which was calculated to be the highest blood level reached during clinical trials in the past) induced an average release of about 3000 ng/ml C3a (baseline levels <140 ng/ml). Analyzing the nature of anti-adenoviral antibodies showed, that not only antibodies with neutralizing properties (anti-Ad5), but also non-neutralizing anti-adenoviral antibodies are capable of complement activation. This study suggests that complement activation can be ignored in local low-dose applications of recombinant adenoviruses, but warrants attention after systemic application of large viral quantities. In clinical protocols aiming at systemic virus application, measures for monitoring and controlling the complement system should be included on a regular basis.

Is there a benefit of preoperative meningioma embolization?

OBJECTIVE

To evaluate the effect of preoperative embolization of meningiomas on surgery and outcomes.

METHODS

In a prospective study, 60 consecutive patients with intracranial meningiomas who were treated in two neurosurgical centers were included. In Center A, embolization was performed for none of the patients (n = 30). In Center B, 30 consecutive patients with embolized meningiomas were treated. Preoperatively, tumor size and location, neurological status, and Barthel scale score were recorded. In Center B, the extent of tumor devascularization was evaluated using angiography and postembolization magnetic resonance imaging. Intraoperatively, blood loss, the numbers of blood units transfused, and the observations of the neurosurgeon concerning hemostasis, tumor consistency, and intratumoral necrosis were recorded. Postoperatively, the neurological status and duration of hospitalization were recorded. Six months after surgery, the outcomes were assessed using the Barthel scale and neurological examinations.

RESULTS

The mean tumor sizes were 22.9 cc in Center A and 29.6 cc in Center B (P > 0.1). The mean blood losses did not differ significantly (646 ml in Center A versus 636 ml in Center B; P > 0.5). However, for a subgroup of patients with subtotal devascularization (>90% of the tumor) on postembolization magnetic resonance imaging scans in Center B, blood loss was less, compared with the entire group in Center A (P < 0.05). The observations of the neurosurgeon regarding hemostasis, tumor consistency, and intratumoral necrosis did not differ significantly. There were no surgery-related deaths in either center. The rates of surgical morbidity, with permanent neurological worsening, were 20% (n = 6) in Center A and 16% (n = 5) in Center B. There was one permanent neurological deficit (3%) caused by embolization.

CONCLUSION

In this preliminary study, only complete embolization had an effect on blood loss. The value of preoperative embolization for all meningiomas must be reconsidered, especially in view of the high costs and risks of embolization.

[Value of transcranial doppler ultrasonography compared with scintigraphic techniques and EEG in brain death]

Since 1991 transcranial doppler sonography has been accepted in Germany as a technical confirmatory test for the assessment of a cerebral circulatory arrest in patients fulfilling the clinical criteria of brain death. This study correlated transcranial doppler findings to established scintigraphic methods such as planar scintigraphy, 99mTc-HMPAO SPECT and EEG patterns. 21 patients (15 males/6 females, mean age 15-69 yrs.) fulfilled all clinical criteria of brain death. They suffered from head injuries and spontaneous bleedings. All clinical and technical investigations were performed within 60-90 minutes. In 14/21 patients clinical findings and all confirmatory tests were consistent with brain death. Planar scintigraphy and SPECT gave completely corresponding results in all 21 patients. 7 patients showed not corresponding results. In two head-injured patients with skull defects TCD yielded an oscillating flow in the MCA but SPECT/planar scintigraphy gave a residual perfusion in the related brain areas. A corresponding residual EEG pattern was seen in one case. A patient with osteoclastic skull defect showed a collateral flow from the external carotid artery and another case a secondary reperfusion in depth of a regular expected MCA signal 12 hours after definitely verification of systolic spikes in the Circle of Willis. No cerebral perfusion was detectable in the scintigraphique techniques. In the three remainder with rest activity in EEG, TCD and radionuclide methods showed no intracranial perfusion. In the presence of open skull fractures, external liquor drainages and osteoclastic craniotomies oscillating flow in TCD does not constantly represent a cerebral circulatory arrest. Awaiting of systolic spikes is absolutely necessary, if no radionuclide method is available. Determination of brain death by TCD should be carried out by an experienced investigator since unexpected collateral flow signals can be misinterpreted.

Detection of two variants of complement component C3 in C3-deficient guinea pigs distinguished by the absence and presence of a thiolester

The complement system is an essential part of the innate defense, and C3 is an integral part of this powerful system. In previously identified complement C3 deficient guinea pigs only approx. 5% of the normal serum C3 level is detectable. No differences were found between in vitro C3 protein synthesis and C3 mRNA levels of cells from C3-deficient and wild-type animals and the amino acid sequences of both C3 proteins are identical as deduced from cDNA sequencing. Previously, the principal inability to form a C3 thiolester was discussed as a possible reason for this C3-deficiency. Here we report the isolation of two functionally different C3 species from the C3-deficient animals. Only one of these C3 proteins exhibits normal hemolytic activity and contains a thiolester group. The second C3 species is exclusively present in C3-deficient animals and lacks a thiolester, explaining its failure to express hemolytic activity. The presence of a second C3 species lacking a thiolester structure only in C3-deficient animals indicates that the stability of the thiolester may play a role in C3 deficiency. However further analysis of the in vitro stability of the thiolesters of C3 from normal and C3-deficient guinea pigs revealed no differences. A decreased in vivo thiolester stability might lead to the presence of C3 with and without a thiolester or alternatively the expression of two isoforms of C3 in these animals. Considering the central role of C3 in host defense, the mechanisms of C3 thiolester formation require further analysis.

Comparison of immunogenicity and safety of a virosome influenza vaccine with those of a subunit influenza vaccine in pediatric patients with cystic fibrosis

The objective of this study was to compare the immunogenicity and safety of a single-dose regimen and a two-dose regimen of a trivalent virosome influenza vaccine (Inflexal Berna V) with those of a trivalent subunit influenza vaccine (Influvac) in children and adolescents with cystic fibrosis (CF). In an open, randomized, multicenter study with parallel groups, 11 young children with CF (1 to 6 years old) and 53 older children and adolescents with CF (>6 years old) were randomly assigned to one of the following immunization regimens: virosome vaccine at 0.5 ml on study day 0 or 0.25 ml on days 0 and 28 or a standard regimen of subunit vaccine, i. e., 0.5 ml on day 0 for older children and 0.25 ml on days 0 and 28 for younger children. Safety assessments, i.e., recording of systemic and local adverse events (AEs) and vital signs, were made for a 5-day observation period after each immunization. Hemagglutination inhibition (HI) titers were determined at baseline and 4 weeks after the single-dose and the two-dose immunizations, respectively. Immunogenicity was assessed according to the criteria of the European Agency for the Evaluation of Medicinal Products (EMEA). Both vaccines induced comparable HI antibody titers. Seroconversion (> or =4-fold rise in HI antibody titers, reaching a titer of > or =1:40) was achieved in 41 to 100% of the participants. Seroprotection (HI titer, > or =1:40) and a >2.5-fold increase in geometric mean titers were achieved in 100% of the participants. Thus, all three EMEA requirements for influenza vaccine efficacy were met by all treatment groups and for both vaccines. The virosome vaccine, when administered as a single dose, seemed to induce superior immunogenicity compared with the standard pediatric two-dose regimen. Totals of 42 and 57% of vaccinees receiving virosome and subunit vaccines, respectively, reported at least one local AE (predominantly pain). Totals of 84 and 71% of subjects receiving virosome and subunit vaccines, respectively, complained in response to questions of at least one systemic AE (mainly cough, fatigue, coryza, or headache). The majority of events were mild or moderate and lasted 1 or 2 days only. No obvious relationship was found between AE reporting rate and vaccine formulation, age group, or dose regimen. The relatively high AE reporting rate seemed to be partly related to the symptomatology of the underlying CF disease. In summary, the virosome and subunit vaccines induced in both age groups and against all three influenza strains an efficient immune response and were well tolerated by the children and adolescents with CF.

Efficacy of trisacryl gelatin microspheres versus polyvinyl alcohol particles in the preoperative embolization of meningiomas

BACKGROUND AND PURPOSE

Trisacryl gelatin microspheres are a new, commercially available nonabsorbable embolic agent. The purpose of this study was to evaluate their efficacy in the preoperative embolization of meningiomas as compared with polyvinyl alcohol (PVA) particles of various sizes.

METHODS

In 30 consecutive patients, trisacryl gelatin microspheres (150-300 microm) were used for the preoperative superselective embolization of meningiomas (group 1). Thirty other consecutive patients had embolization with PVA particles of 45 to 150 microm (n = 15, group 2) and of 150 to 250 microm (n = 15, group 3). Extent of devascularization, intraoperative blood loss, blood transfusion, and hemostasis at the time of surgery were recorded for every patient. The inflammatory reaction, the extent of necrotic areas, and the most distal intravascular location of the embolic agent (arterial, arteriolar, precapillary, capillary) were recorded.

RESULTS

There was no significant difference in the extent of angiographic devascularization among the groups. Intraoperative blood loss differed significantly between groups 1 and 2 and groups 1 and 3, but not between groups 2 and 3. The trisacryl gelatin microspheres were located more distally in tumor vessels than were the PVA particles of either size. The extent of intratumoral necrosis was not significantly different between the two embolic agents. In all groups there was a mild inflammatory tissue reaction in the vicinity of the embolic agent.

CONCLUSION

Trisacryl gelatin microspheres may be effective in the preoperative embolization of meningiomas, producing significantly less blood loss at surgery than seen with PVA particles of either size, possibly because of the significantly more distal vascular penetration of the microspheres.

MR spectroscopy in gliomatosis cerebri

BACKGROUND AND PURPOSE

The diagnosis of gliomatosis cerebri with MR imaging is known to be difficult. We report on the value of MR spectroscopy in the diagnosis, grading, and biopsy planing in eight patients with histopathologically proved gliomatosis cerebri.

METHODS

Patients underwent MR imaging and MR spectroscopy (single-voxel point-resolved spectroscopy [PRESS] at 1500/135, and chemical-shift imaging [CSI] PRESS at 1500/135) before open (n = 4) or stereotactic (n = 4) biopsy. In six patients who underwent CSI, biopsy samples were taken from regions of maximally elevated levels of choline/N-acetylaspartate (Cho/NAA).

RESULTS

All patients showed elevated Cho/creatine (Cr) and Cho/NAA levels as well as varying degrees of decreased NAA/Cr ratios, which were most pronounced in the anaplastic lesions. In low-grade lesions, there was a maximum Cho/NAA ratio of 1.3, whereas in anaplastic tumors, the maximum Cho/NAA level was at least 2.5. Spectra in two patients with grade III lesions revealed a lactate peak; lactate and lipid signals were seen in two patients with grade IV lesions. Biopsy specimens from regions with maximally elevated levels of Cho/NAA showed dense infiltration of tumor cells.

CONCLUSION

MR spectroscopy might be used to classify gliomatosis cerebri as a stable or a progressive disease indicating its potential therapeutic relevance.

Interrelations of laser doppler flowmetry and brain tissue oxygen pressure during ischemia and reperfusion induced by an experimental mass lesion

The objective of this study was to assess interrelations between bilateral changes of cortical laser doppler flowmetry and intraparenchymal, subcortical partial tissue oxygen tension in the course of an experimental trauma. Ten animals served as a sham group, 8 Sprague-Dawley rats received an unilateral, focal parietal mass lesion. The bilateral course of cortical blood flow measured by laser doppler flowmetry (LDF) was correlated with subcortical, intraparenchymal partial tissue oxygen tension [p(ti)O2]. In the sham-operated group, laser doppler mean flow values drifted between 9.0% and 9.5% and showed no significant changes over time neither between the hemispheres nor within each hemisphere. Absolute mean p(ti)O2 in sham-operated animals was 32.4 mm Hg in the left and 30.5 mm Hg in the right hemisphere. In the trauma group, mean laser doppler flow values during maximum brain compression decreased ipsilateral to 20.3% and contralateral to 34.4% of the baseline values. P(ti)O2 decreased ipsilateral from 25.9 to 6.6 mm Hg (25.4%) and contralateral from 22.6 to 9.8 mm Hg (43.6%). After balloon deflation, cortical LDF was restored much faster compared to p(ti)O2, but did not reach baseline values [ipsilateral 61.6% (p < 0.05); contralateral 75.8% of baseline values]. The p(ti)O2 values reached 25.2 mm Hg (97%) ipsilateral and 23.7 mm Hg (105%) contralateral. A temporary phase of reactive hyperemia occurred sporadically shortly after decompression. Both parameters showed a significant but rather weak correlation (r = 0.56; p < 0.001). Based upon these findings, we conclude that intraparenchymal, subcortical p(ti)O2 measurements supplemented on-line cortical CBF monitoring and score out discontinuous alternative measurement techniques in detecting hemodynamically relevant events. The small spatial resolution of LDF and p(ti)O2 probes, however, which in the small animal model may be of negligible influence, does raise the question whether the values obtained represent the microcirculatory situation of the human brain.

Silent embolism in diagnostic cerebral angiography and neurointerventional procedures: a prospective study

BACKGROUND

Cerebral angiography is associated with a small but definite risk of neurological complications with an unknown incidence of clinically silent embolism. We assessed the neurological complication rate compared with the frequency of silent embolism after angiography

METHODS

We used diffusion-weighted magnetic resonance imaging (MRI) before and after angiography to assess embolic events. 100 consecutive angiographies (66 diagnostic and 34 interventional procedures) were done on 91 patients. Patients underwent neurological assessment before, immediately after, and 1 day after angiography.

FINDINGS

Before angiography, no abnormalities were seen on diffusion-weighted MRI. Diffusion-weighted MRI showed 42 bright lesions in 23 patients after 23 procedures (17 diagnostic, six interventional) in a pattern consistent with embolic events. There was no new neurological deficit after any angiographic procedure. After diagnostic angiography in patients with a history of vasculopathy, the frequency of lesions was significantly higher than in patients without vascular risk factors (12 [44%] of 27 vs five [13%] of 39 patients, p=0.03). In diagnostic angiography, the appearance of lesions was significantly correlated with whether vessels were difficult to probe (p=0.01), amount of contrast medium needed (p<0.01), fluoroscopy time (p<0.01), and use of additional catheters (p=0.02).

INTERPRETATION

After diagnostic and interventional cerebral angiography, embolic events are more frequent than the apparent neurological complication rate. In diagnostic procedures, the incidence of embolism is closely related to a vascular risk profile.

T-cell-activating monoclonal antibodies, reacting with both leukocytes and erythrocytes, recognize the guinea pig Thy-1 differentiation antigen: characterization and cloning of guinea pig CD90

A glycophosphatidylinositol (GPI)-linked differentiation antigen expressed on guinea pig T and B lymphocytes was identified by several monoclonal antibodies; it has been shown previously that this membrane protein induced strong polyclonal T cell proliferation upon antibody binding and costimulation by PMA. Purification by immunoadsorption and microsequencing revealed that this T-cell-activating protein is the homologue of Thy-1 or CD90. In contrast to the Thy-1 antigen of most other species, guinea pig Thy-1 has a much higher molecular weight, which is due to a more extensive N-linked glycosylation, bringing the molecular weight of the total antigen up to 36 kDa. Molecular cloning of guinea pig Thy-1 indicated that the deduced molecular weight of the protein backbone is 12,777 after removal of an N-terminal 19-amino-acid leader peptide and cleavage of the 31 amino acids for GPI anchoring the C-terminal end. Sequence comparison showed that guinea pig Thy-1 has an 82% homology to human and a 72% homology to mouse Thy-1 on the amino acid level. Immunohistological staining of cryostat sections revealed intensive staining with the monoclonal antibody H154 on fibroblasts, fibrocytes, Kupffer cells, alveolar macrophages, and mesangial cells. As observed in the human, mouse, and rat, Thy-1 is abundant in the guinea pig brain. Unlike Thy-1 expression in other species, guinea pig Thy-1 is strongly expressed on most resting, nonactivated B cells and, to a lesser extent, on erythrocytes. While treatment of erythrocytes and lymphocytes with GPI-specific phospholipase C largely decreased reactivity with mAb H154, T cells retained the proliferative response to antibody and phorbol esters.

Chylothorax in children: guidelines for diagnosis and management

STUDY OBJECTIVE

To establish guidelines for the diagnosis and management of chylothorax in children.

DESIGN

Retrospective study.

PATIENTS

Fifty-one patients with a diagnosis of chylothorax. Twelve patients were excluded because of incomplete data or incorrect diagnosis. The following parameters were analyzed: triglyceride level, total cell number, and lymphocyte percentage; amount of pleural effusion on day of diagnosis, day 5, and day 14; and total time of pleural effusion. Prospectively, the same parameters were analyzed in a control group of 10 patients with pleural drainage.

INTERVENTION

Patients with chylothorax were treated primarily with fat-free oral nutrition; if chyle did not stop, total parenteral nutrition with total enteric rest was started. If conservative therapy was not successful, pleurodesis was performed.

RESULTS

In children with chylothorax triglyceride, triglyceride content ranged from 0.56 to 26.6 mmol/L; all values except one were > 1.1 mmol/L. In 36 of 39 patients (92%), the cell count was > 1,000 cells/microL. In 33 of 39 patients (85%), lymphocytes were > 90%. In patients without chylothorax triglyceride, triglyceride levels ranged from 0.1 to 0.71 mmol/L (median, 0.38 mmol/L) and cell count was from 20 to 1400 cells/microL (median, 322 cells/microL), with a maximum of 60% lymphocytes. With fat-free nutrition, chyle disappeared in 29 of 39 patients. Five patients died, and five required pleurodesis.

CONCLUSIONS

Pleural effusion in children is chyle when it contains > 1.1 mmol/L triglycerides (with oral fat intake) and has a total cell count > or 1,000 cells/microL, with a lymphocyte fraction > 80%. Chylous effusions usually last long; however, after 6 weeks, the majority of the effusions (29 of 39 patients) had ceased. Late surgical interventions reduce the number of thoracotomies substantially, but can lead to very long hospitalization times. Early surgical interventions (after < 3 weeks) lead to a high number of thoracotomies, but certainly reduce hospitalization time.

Paralysis of ventilated newborn babies does not influence resistance of the total respiratory system

Paralysis with pancuronium bromide is used in newborn infants to facilitate ventilatory support during respiratory failure. Changes in lung mechanics have been attributed to paralysis. The aim of this study was to examine whether or not paralysis per se has an influence on the passive respiratory mechanics, resistance (Rrs) and compliance (Crs) of the respiratory system in newborn infants. In 30 infants with acute respiratory failure, Rrs was measured during paralysis with pancuronium bromide and after stopping pancuronium bromide (group A). Rrs was also measured in an additional 10 ventilated infants in a reversed fashion (group B): Rrs was measured first in nonparalysed infants and then they were paralysed, mainly for diagnostic procedures, and the Rrs measurement repeated. As Rrs is highly dependent on lung volume, several parameters, that depend directly on lung volume were recorded: inspiratory oxygen fraction (FI,O2), arterial oxygen tension/alveolar oxygen tension (a/A) ratio and volume above functional residual capacity (FRC). In group A, the Rrs was not different during (0.236+/-0.09 cmH2O x s x mL(-1)) and after (0.237+/-0.07 cmH2O x s x mL(-1)) paralysis. Also, in group B, Rrs did not change (0.207+/-0.046 versus 0.221+/-0.046 cm x s x mL(-1) without versus with pancuronium bromide). FI,O2, a/A ratio and volume above FRC remained constant during paralysis. These data demonstrate that paralysis does not influence the resistance of the total respiratory system in ventilated term and preterm infants when measured at comparable lung volumes.

Attentional control during visual search: the effect of irrelevant singletons

Four experiments investigated whether a highly salient color singleton can be ignored during serial search. Observers searched for a target letter among nontarget letters and were instructed to ignore an irrelevant, highly salient color singleton that was either compatible or incompatible with the response to the target letter. The results indicate that it was possible to prevent attentional capture by the irrelevant singleton only when both the target and the distractor color were known. When either the color of the target or the color of the to-be-ignored singleton were varied over trials, the irrelevant singleton captured attention. The ability to selectively filter singleton distractors during serial search depends on the presence of an attentional set for a specific feature value of both target and distractor. In the absence of a consistently predictable feature value of both target and distractor, top-down control is not possible.

Heterogeneity of T-acute lymphoblastic leukemia (T-ALL) cell lines: suggestion for classification by immunophenotype and T-cell receptor studies

Hematopoietic cell lines are often used as representatives for a certain cell differentiation lineage and stage, particularly in immunological and hematological studies. Acute lymphoblastic leukemia (ALL) of T-cell type is a rather heterogeneous group of ALL at least by immunophenotyping. Our aim was to present a comprehensive characterization of frequently used T-cell leukemia cell lines and to suggest a correlation with the normal differentiation pattern. A total of 16 T-ALL cell lines were analyzed for their immunophenotype and for T-cell receptor (TCR) rearrangement and expression. The panel of 20 cell surface markers included two new monoclonal antibodies (MoAb), TC-12 and TH-111, which were raised in our laboratory and detect subpopulations of T-cell ALL. TC-12 was typed 'unique', TH-111 was assigned to the CD96 cluster at the Vth Conference on human leucocyte differentiation antigens (HLDA). We categorized the 16 cell lines into the four groups pro-T, pre-T, cortical T and mature T differentiation stage according to the recent proposal of the European Group for the Immunological Characterization of Leukemias (EGIL). Interestingly, none of the T-cell lines were found to be alike. In conclusion, it appears necessary to consider the particular differentiation stage of each individual cell line when using T-cell leukemia lines as models for malignant or normal T cells.