Ultrafast Spectral Tuning of a Fiber Laser for Time-Encoded Multiplex Coherent Raman Scattering Microscopy

Coherent Raman scattering microscopy utilizing bioorthogonal tagging approaches like isotope or alkyne labeling allows for a targeted monitoring of spatial distribution and dynamics of small molecules of interest in cells, tissues, and other complex biological matrices. To fully exploit this approach in terms of real-time monitoring of several Raman tags, e.g., to study drug uptake dynamics, extremely fast tunable lasers are needed. Here, we present a laser concept without moving parts and fully electronically controlled for the quasi-simultaneous acquisition of coherent anti-Stokes Raman scattering images at multiple Raman resonances. The laser concept is based on the combination of a low noise and spectrally narrow Fourier domain mode-locked laser seeding a compact four wave mixing-based high-power fiber-based optical parametric amplifier.

Time-encoded stimulated Raman scattering microscopy of tumorous human pharynx tissue in the fingerprint region from 1500-1800 cm-1

Stimulated Raman scattering (SRS) microscopy for biomedical analysis can provide a molecular localization map to infer pathological tissue changes. Compared to spontaneous Raman, SRS achieves much faster imaging speeds at reduced spectral coverage. By targeting spectral features in the information dense fingerprint region, SRS allows fast and reliable imaging. We present time-encoded (TICO) SRS microscopy of unstained head-and-neck biopsies in the fingerprint region with molecular contrast. We combine a Fourier-domain mode-locked (FDML) laser with a master oscillator power amplifier (MOPA) to cover Raman transitions from 1500-1800cm^-1. Both lasers are fiber-based and electronically programmable making this fingerprint TICO system robust and reliable. The results of our TICO approach were cross-checked with a spontaneous Raman micro-spectrometer and show good agreement, paving the way toward clinical applications.

Live video rate volumetric OCT imaging of the retina with multi-MHz A-scan rates

Surgical microscopes are vital tools for ophthalmic surgeons. The recent development of an integrated OCT system for the first time allows to look at tissue features below the surface. Hence, these systems can drastically improve the quality and reduce the risk of surgical interventions. However, current commercial OCT-enhanced ophthalmic surgical microscopes provide only one additional cross sectional view to the standard microscope image and feature a low update rate. To present volumetric data at a high update rate, much faster OCT systems than the ones applied in today's surgical microscopes need to be developed. We demonstrate live volumetric retinal OCT imaging, which may provide a sufficiently large volume size (330x330x595 Voxel) and high update frequency (24.2 Hz) such that the surgeon may even purely rely on the OCT for certain surgical maneuvers. It represents a major technological step towards the possible application of OCT-only surgical microscopes in the future which would be much more compact thus enabling many additional minimal invasive applications. We show that multi-MHz A-scan rates are essential for such a device. Additionally, advanced phase-based OCT techniques require 3D OCT volumes to be detected with a stable optical phase. These techniques can provide additional functional information of the retina. Up to now, classical OCT was to slow for this, so our system can pave the way to holographic OCT with a traditional confocal flying spot approach. For the first time, we present point scanning volumetric OCT imaging of the posterior eye with up to 191.2 Hz volume rate. We show that this volume rate is high enough to enable a sufficiently stable optical phase to a level, where remaining phase errors can be corrected. Applying advanced post processing concepts for numerical refocusing or computational adaptive optics should be possible in future with such a system.

Live video rate volumetric OCT imaging of the retina with multi-MHz A-scan rates

Surgical microscopes are vital tools for ophthalmic surgeons. The recent development of an integrated OCT system for the first time allows to look at tissue features below the surface. Hence, these systems can drastically improve the quality and reduce the risk of surgical interventions. However, current commercial OCT-enhanced ophthalmic surgical microscopes provide only one additional cross sectional view to the standard microscope image and feature a low update rate. To present volumetric data at a high update rate, much faster OCT systems than the ones applied in today's surgical microscopes need to be developed. We demonstrate live volumetric retinal OCT imaging, which may provide a sufficiently large volume size (330x330x595 Voxel) and high update frequency (24.2 Hz) such that the surgeon may even purely rely on the OCT for certain surgical maneuvers. It represents a major technological step towards the possible application of OCT-only surgical microscopes in the future which would be much more compact thus enabling many additional minimal invasive applications. We show that multi-MHz A-scan rates are essential for such a device. Additionally, advanced phase-based OCT techniques require 3D OCT volumes to be detected with a stable optical phase. These techniques can provide additional functional information of the retina. Up to now, classical OCT was to slow for this, so our system can pave the way to holographic OCT with a traditional confocal flying spot approach. For the first time, we present point scanning volumetric OCT imaging of the posterior eye with up to 191.2 Hz volume rate. We show that this volume rate is high enough to enable a sufficiently stable optical phase to a level, where remaining phase errors can be corrected. Applying advanced post processing concepts for numerical refocusing or computational adaptive optics should be possible in future with such a system.

Wavelength agile multi-photon microscopy with a fiber amplified diode laser

Multi-photon microscopy is a powerful tool in biomolecular research. Less complex and more cost effective excitation light sources will make this technique accessible to a broader community. Semiconductor diode seeded fiber lasers have proven to be especially robust, low cost and easy to use. However, their wavelength tuning range is often limited, so only a limited number of fluorophores can be accessed. Therefore, different approaches have been proposed to extend the spectral coverage of these lasers. Recently, we showed that four-wave mixing (FWM) assisted stimulated Raman scattering (SRS) can be harnessed to red-shift high power pulses from 1064 nm to a narrowband output at 1122 nm and 1186 nm and therefore extend the number of accessible fluorophores. In this contribution, we show the applicability of all three wavelengths for multi-photon microscopy and analyze the performance.

High-resolution retinal swept source optical coherence tomography with an ultra-wideband Fourier-domain mode-locked laser at MHz A-scan rates

We present a new 1060 nm Fourier domain mode locked laser (FDML laser) with a record 143 nm sweep bandwidth at 2∙ 417 kHz  =  834 kHz and 120 nm at 1.67 MHz, respectively. We show that not only the bandwidth alone, but also the shape of the spectrum is critical for the resulting axial resolution, because of the specific wavelength-dependent absorption of the vitreous. The theoretical limit of our setup lies at 5.9 µm axial resolution. In vivo MHz-OCT imaging of human retina is performed and the image quality is compared to the previous results acquired with 70 nm sweep range, as well as to existing spectral domain OCT data with 2.1 µm axial resolution from literature. We identify benefits of the higher resolution, for example the improved visualization of small blood vessels in the retina besides several others.

Combined in-depth, 3D, en face imaging of the optic disc, optic disc pits and optic disc pit maculopathy using swept-source megahertz OCT at 1050 nm

Purpose

To demonstrate papillary imaging of eyes with optic disc pits (ODP) or optic disc pit associated maculopathy (ODP-M) with ultrahigh-speed swept-source optical coherence tomography (SS-OCT) at 1.68 million A-scans/s. To generate 3D-renderings of the papillary area with 3D volume-reconstructions of the ODP and highly resolved en face images from a single densely-sampled megahertz-OCT (MHz-OCT) dataset for investigation of ODP-characteristics.

Methods

A 1.68 MHz-prototype SS-MHz-OCT system at 1050 nm based on a Fourier-domain mode-locked laser was employed to acquire high-definition, 3D datasets with a dense sampling of 1600 × 1600 A-scans over a 45° field of view. Six eyes with ODPs, and two further eyes with glaucomatous alteration or without ocular pathology are presented. 3D-rendering of the deep papillary structures, virtual 3D-reconstructions of the ODPs and depth resolved isotropic en face images were generated using semiautomatic segmentation.

Results

3D-rendering and en face imaging of the optic disc, ODPs and ODP associated pathologies showed a broad spectrum regarding ODP characteristics. Between individuals the shape of the ODP and the appending pathologies varied considerably. MHz-OCT en face imaging generates distinct top-view images of ODPs and ODP-M. MHz-OCT generates high resolution images of retinal pathologies associated with ODP-M and allows visualizing ODPs with depths of up to 2.7 mm.

Conclusions

Different patterns of ODPs can be visualized in patients for the first time using 3D-reconstructions and co-registered high-definition en face images extracted from a single densely sampled 1050 nm megahertz-OCT (MHz-OCT) dataset. As the immediate vicinity to the SAS and the site of intrapapillary proliferation is located at the bottom of the ODP it is crucial to image the complete structure and the whole depth of ODPs. Especially in very deep pits, where non-swept-source OCT fails to reach the bottom, conventional swept-source devices and the MHz-OCT alike are feasible and beneficial methods to examine deep details of optic disc pathologies, while the MHz-OCT bears the advantage of an essentially swifter imaging process.

Electronic supplementary material

The online version of this article (10.1007/s00417-017-3857-9) contains supplementary material, which is available to authorized users.

Pulse-to-pulse wavelength switching of a nanosecond fiber laser by four-wave mixing seeded stimulated Raman amplification

We report on a multi-color fiber laser based on four-wave mixing (FWM) and stimulated Raman scattering (SRS), delivering rapidly wavelength switchable narrowband output at 1064, 1122, and 1186 nm. High-power pulses from a nanosecond pulsed fiber master oscillator power amplifier at 1064 nm are combined with 1122 nm of seed light for Raman amplification at the first Stokes order in a standard single-mode fiber. With increasing power, we observe a narrowband spectral component at 1186 nm, without any additional seed or resonator at this wavelength. We analyze this occurrence of a narrowband second Stokes order both experimentally and theoretically and suggest it is a result of FWM seeding of the SRS amplification in the fiber. We demonstrate that the wavelength shifting can be controlled electronically within microseconds for very rapid and even pulse-to-pulse wavelength changes. This wavelength conversion method can extend the spectral coverage of single-wavelength fiber lasers for biomedical imaging.

Single pulse two photon fluorescence lifetime imaging (SP-FLIM) with MHz pixel rate

Two-photon-excited fluorescence lifetime imaging microscopy (FLIM) is a chemically specific 3-D sensing modality providing valuable information about the microstructure, composition and function of a sample. However, a more widespread application of this technique is hindered by the need for a sophisticated ultra-short pulse laser source and by speed limitations of current FLIM detection systems. To overcome these limitations, we combined a robust sub-nanosecond fiber laser as the excitation source with high analog bandwidth detection. Due to the long pulse length in our configuration, more fluorescence photons are generated per pulse, which allows us to derive the lifetime with a single excitation pulse only. In this paper, we show high quality FLIM images acquired at a pixel rate of 1 MHz. This approach is a promising candidate for an easy-to-use and benchtop FLIM system to make this technique available to a wider research community.

Two-photon microscopy using fiber-based nanosecond excitation

Two-photon excitation fluorescence (TPEF) microscopy is a powerful technique for sensitive tissue imaging at depths of up to 1000 micrometers. However, due to the shallow penetration, for in vivo imaging of internal organs in patients beam delivery by an endoscope is crucial. Until today, this is hindered by linear and non-linear pulse broadening of the femtosecond pulses in the optical fibers of the endoscopes. Here we present an endoscope-ready, fiber-based TPEF microscope, using nanosecond pulses at low repetition rates instead of femtosecond pulses. These nanosecond pulses lack most of the problems connected with femtosecond pulses but are equally suited for TPEF imaging. We derive and demonstrate that at given cw-power the TPEF signal only depends on the duty cycle of the laser source. Due to the higher pulse energy at the same peak power we can also demonstrate single shot two-photon fluorescence lifetime measurements.

A Time-Encoded Technique for fibre-based hyperspectral broadband stimulated Raman microscopy

Raman sensing and microscopy are among the most specific optical technologies to identify the chemical compounds of unknown samples, and to enable label-free biomedical imaging. Here we present a method for stimulated Raman scattering spectroscopy and imaging with a time-encoded (TICO) Raman concept. We use continuous wave, rapidly wavelength-swept probe lasers and combine them with a short-duty-cycle actively modulated pump laser. Hence, we achieve high stimulated Raman gain signal levels, while still benefitting from the narrow linewidth and low noise of continuous wave operation. Our all-fibre TICO-Raman setup uses a Fourier domain mode-locked laser source to achieve a unique combination of high speed, broad spectral coverage (750–3,150 cm⁻¹) and high resolution (0.5 cm⁻¹). The Raman information is directly encoded and acquired in time. We demonstrate quantitative chemical analysis of a solvent mixture and hyperspectral Raman microscopy with molecular contrast of plant cells.

Raman microscopes suffer from the compromise between speed and spectral information and are often unsuited for fibre beam delivery. Karpf et al. overcome these limitations using continuous-wave rapidly wavelength-swept probe lasers and a short-duty-cycle actively modulated pump laser in an all-fibre setup.

Radiological anatomy of the ambient cistern in children

Ambient cistern (AC) is a thin extension of the subarachnoid space surrounding the brainstem at the level of the mesencephalon and pons. Despite various definitions, it constitutes an important landmark in clinical assessment of intracranial volume reserve. Although it is indisputably useful, there exists no defined standard for radiological examination for the dimensions and ranges in specific age groups. This paper aims to describe the ambient cistern anatomically and give the ranges of dimensions for proper radiological interpretation. The study was performed on 160 axial computed tomography (CT) examinations of Polish children of both sexes, aged 1-18 years, admitted to the hospital because of mild brain concussion. Pictures were made using a Siemens 8-row CT scanner, without contrast administration. We estimated distances at the level of the pons and midbrain, based on axial cross-sections, according to standard radiological protocol. The parameters included the width of the AC in its anterior and posterior part, the width of the tentorial notch, and the distance from the pons and sella. All measurements were analyzed statistically with StatSoft Statistica 8.0 software. The average width of the AC differs between age groups. It is greatest at 1-3 years (2.8 +/- 0.6 mm) and lowest at 4-10 years (2.4 +/- 0.6 mm). AC is more likely to be greater in its anterior part in boys. The distance from the sella to the pons is greatest in 1-3-year-old girls (6.9 +/- 1.3 mm), and the tentorial notch is widest in the 15-18-year-old group (24.6 +/- 2.4 mm). Dimensions of the AC correlate with intracranial reserve volume. This is particularly visible in the youngest children. Thin and narrow AC is not always a sign of raised intracranial pressure. It may be specific for the child's age.

High-risk AML complicated by pulmonary aspergillosis: successful treatment with nonmyeloablative stem cell transplantation and long-term administration of voriconazole

Acute myeloid leukemia (AML) associated with central diabetes insipidus (DI) and chromosomal aberrations is characterised by a very poor prognosis. We present a 28-year-old female with AML FAB M0, preceding DI and cytogenetic abnormalities (monosomy 7 and inversion of chromosome 9). Complete remission was achieved with FLAG after she was refractory to two different induction regimens. Prolonged neutropenia resulted in invasive pulmonary aspergillosis. Allogeneic stem cell transplantation from a matched unrelated donor was performed using a reduced-intensity conditioning regimen. Desmopressin substitution for DI was withdrawn after transplant without recurrence of symptoms. Initial antifungal treatment, including liposomal amphotericin B, caspofungin and itraconazole, was replaced by voriconazole after deterioration of pulmonary aspergillosis, resulting in improvement, stabilisation and finally, also as the combined effect of discontinuation of the immunosuppressive therapy, in disappearance of signs and symptoms. Thirteen months after transplant, the patient is in continuous complete remission. The presented case study thus demonstrates that high-risk AML with concomitant invasive fungal infection may be safely and effectively treated by nonmyeloablative stem cell transplantation and long-term administration of voriconazole.

Accuracy of whole-body 18F-FDP-PET for restaging malignant lymphoma

BACKGROUND

The aim of this retrospective study was to evaluate the accuracy of fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG-PET) images, which were interpreted under daily routine conditions, in patients with Hodgkin's disease (HD) or non-Hodgkin lymphoma (NHL) for restaging after chemotherapy and/or radiotherapy. For this purpose, 18F-FDG-PET results were compared with morphological imaging methods and the patients' clinical background.

METHODS

121 PET images of 93 lymphoma patients (44 HD, 49 NHL) were investigated after chemotherapy/radiotherapy. For PET imaging, 160-200 MBq 18F-FDG was administered intravenously, followed by an infusion of 20 mg Furosemid in 250 mL saline. Whole-body 18F-FDG-PET images were obtained using a partial-ring PET scanner without attenuation correction. The morphological imaging consisted in computed tomography and ultrasound (CT/US) in all patients, additional MRI in some patients, and iliac crest biopsy in cases of suspicious bone marrow involvement. The standard of reference was composed of biopsy data, clinical status at the time of investigation, and follow-up of at least 12 months. The PET images were evaluated for their sensitivity, specificity and accuracy based on written reports, which were compiled from other imaging data and the clinical history of the patients.

RESULTS

Sensitivity, specificity, and accuracy of 18F-FDG-PET was 91 %, 81 %, and 85 %; of CT/US, 88 %, 35 %, 56 %, respectively. Major sources of error in 18F-FDG-PET were due to asymmetric muscular hypermetabolism and inflammatory lesions misinterpreted as persistent viable lymphoma tissue. Furthermore, secondary malignancies other than lymphomas were another reason for misinterpretations of 18F-FDG-PET studies.

CONCLUSIONS

18F-FDG-PET showed a comparable sensitivity but a higher specificity and accuracy compared with CT/US. To achieve a high accuracy in 18F-FDG-PET, the nuclear medicine specialist needs imaging and clinical data as background information, which can only be acquired through close co-operation with the referring clinicians. Pharmacological muscular relaxation in the course of 18F-FDG-PET imaging may be advisable, as nonspecific muscular hypermetabolism was one of the problems at the image readings and a source of incorrect 18F-FDG-PET interpretations.

Acute pseudo-obstruction of the small intestine following high-dose chemotherapy and stem cell support

BACKGROUND

Acute intestinal pseudo-obstruction is a potentially life-threatening disease which is characterized by massive dilation of the colon or small intestine without mechanical obstruction and may develop after surgery or severe illness.

PATIENTS AND METHODS

We report 2 cases in which acute small intestinal pseudo-obstruction occurred after high-dose chemotherapy and autologous stem cell support. In 1 patient explorative abdominal laparoscopy was performed to rule out mechanical ileus. However, after having initiated treatment with acetylcholinesterase inhibitors a prompt small intestinal decompression was observed in both patients.

CONCLUSIONS

Acetylcholinesterase inhibitors should be considered as an early conservative intervention in the treatment of acute intestinal pseudo-obstruction to avoid surgery of patients undergoing high-dose chemotherapy with autologous stem cell support.

Monitoring of cardiac function by serum cardiac troponin T levels, ventricular repolarisation indices, and echocardiography after conditioning with fractionated total body irradiation and high-dose cyclophosphamide

OBJECTIVES

Highly differing rates of cardiac complications associated with high-dose cyclophosphamide (CY) have been reported, and only one clinical study has been performed on the cardiotoxic effects of CY monotherapy following total body irradiation (TBI).

PATIENTS AND METHODS

We prospectively evaluated the potential cardiotoxic effects of conditioning with fractionated total body irradiation and high-dose cyclophosphamide (TBI/CY) by serial measurement of serum cardiac troponin T (cTnT), assessment of systolic and diastolic echocardiographic parameters and analysis of ventricular repolarisation indices (QT-dispersion and corrected QT-dispersion) in 30 adult patients with haematological malignancies undergoing haematopoietic stem cell transplantation.

RESULTS

There was no evidence of pretreatment cardiac dysfunction in any patient. Although cTnT was determined serially for a median of 14 d after completion of conditioning, no elevated levels were observed. Echocardiographic parameters did not show any significant change at a median follow-up of 5 months except for one patient with evidence of impaired diastolic filling. No significant differences for mean values before and after high-dose CY were noted for ventricular repolarisation indices. Two patients had a significant increase in corrected QT-dispersion after CY without any other signs of cardiotoxicity. Congestive heart failure or arrhythmias were not observed.

CONCLUSIONS

These data suggest that TBI/CY is safe with respect to cardiotoxicity in patients without pre-existing cardiac dysfunction. Hitherto unknown synergistic cardiotoxic effects of CY with other cytostatic drugs may constitute the major pathogenic factor of myocardial dysfunction after high-dose chemotherapy.

Hepatic veno-occlusive disease in two patients with relapsed acute myeloid leukemia treated with anti-CD33 calicheamicin (CMA-676) immunoconjugate

Monoclonal antibodies recognizing hematopoietic antigens are increasingly being used to target therapy directly at leukemic cells, with the aim of achieving sustained remission with little systemic toxicity. Administration of anti-CD33 calicheamicin immunoconjugate is commonly regarded as being safe, with only moderate systemic non-hematological side effects. We report on two cases of hepatic veno-occlusive disease in heavily pretreated patients presenting with relapsed acute myeloid leukemia (AML). Since significant liver toxicity prevented further specific therapy in both patients, we recommend that antibody therapy with anti-CD33 immunoconjugate should be applied with caution in patients presenting with risk factors for the development of hepatic veno-occlusive disease.

Amifostine in combination with erythropoietin and G-CSF promotes multilineage hematopoiesis in patients with myelodysplastic syndrome

Ineffective hematopoiesis leading to profound cytopenias represents a major clinical problem in the management of patients with myelodysplastic syndrome (MDS). The aminothiol amifostine has shown to promote multilineage hematopoiesis both in vivo and in vitro in patients with MDS. We have treated 10 patients with 250 mg/m2 amifostine thrice weekly in combination with erythropoietin for 4 consecutive weeks followed by 2 weeks observation. Responding patients received the same 6 week schedule, while nonresponder received G-CSF in addition to erythropoietin and amifostine during the second treatment course. All patients experienced single or multilineage hematologic improvement, but only 2 reached transfusion independency. Moreover, response was durable only in a minority of patients and thus additional studies are warranted to further define the potential interaction of amifostine and growth factors.

Cytomegalovirus diagnosis in renal and bone marrow transplant recipients: the impact of molecular assays

BACKGROUND

Cytomegalovirus (CMV) infections are a major threat in transplant recipients. In recent years, new assays for routine CMV diagnosis, based on molecular techniques, have become available.

OBJECTIVE

The impact of molecular assays for CMV diagnosis in transplant recipient was evaluated.

STUDY DESIGN

A total of 51 transplant recipients were screened for CMV infection. Serological (AxSYM CMV IgG and recombinant CMV IgM assays), antigenemia, CMV DNA (qualitative in house PCR and the quantitative COBAS AMPLICOR CMV MONITOR Test), and CMV mRNA (NucliSens CMV pp67 Test) tests were compared.

RESULTS

In 11/20 bone marrow transplant (BMT) recipients and 10/31 renal transplant (RTX) recipients there was no evidence of active CMV infection. Ten RTX recipients and one BMT recipient were antigenemia positive, 21 RTX and seven BMT recipients were PCR positive (qualitative CMV PCR). There were more BMT recipients CMV DNA positive in serum (7/21) than antigenemia positive (1/21). CMV mRNA was found positive in two BMT recipients (one case with no other evidence of CMV infection, the other one CMV DNA positive and antigenemia negative). The only antigenemia positive BMT recipient was found negative for CMV mRNA, but positive in all other tests. Eight RTX recipients were found positive for CMV mRNA. Six of them were also antigenemia positive and five of those were also found positive for CMV IgM. One CMV mRNA positive RTX recipient was CMV IgM positive but antigenemia negative and the other one CMV mRNA positive RTX recipient was found negative in all other tests. Two antigenemia positive RTX recipients were found negative for mRNA and CMV IgM.

CONCLUSION

Antigenemia was found to be a good screening test for CMV infection in RTX recipients. In BMT recipients, tests based on molecular techniques appeared to be superior compared to antigenemia.

Preterm infants with low immunoglobulin G levels have increased risk of neonatal sepsis but do not benefit from prophylactic immunoglobulin G

OBJECTIVE

In a prospective, randomized, placebo-controlled, multicenter study, we evaluated the prevention of neonatal infections with intravenous immunoglobulin G (IVIgG) prophylaxis for preterm infants (gestational age <33 weeks) with umbilical cord blood IgG levels < or =4 g/L.

STUDY DESIGN

Intravenous IgG or placebo (albumin), 1 g/kg body weight, was given on days 0, 3, 7, 14, and 21 to 81 infants with umbilical cord blood IgG levels < or =4 g/L: (1) IVIgG group, n = 40, mean (SD) gestational age 27.5 (2.2) weeks and birth weight 1.06 (0.39) kg; (2) placebo group, n = 41, mean (SD) gestational age 27.7 (2.5) weeks and birth weight 1.13 (0.38) kg. Infants with umbilical cord blood IgG levels >4 g/L (n = 238) served as a separate comparison group. Neonatal infections according to European Society of Pediatric Infectious Disease criteria were monitored until 28 days of life.

RESULTS

Infants with IgG levels < or =4 g/L at birth who received IVIgG had no significant reduction in infectious episodes or mortality rate when compared with those given placebo. However, infants with a serum concentration of IgG >4 g/L at birth had significantly fewer infectious episodes (culture-proven sepsis) than infants with low serum concentrations of IgG (< or =4 g/L) when compared at the same gestational ages (26 to 29 weeks, P <.003).

CONCLUSIONS

Prophylactic immunotherapy with IVIgG did not improve the immune competence in preterm infants with low serum IgG concentrations at birth. We speculate that a spontaneously high serum IgG concentration at birth reflects placenta function and is an indicator of a more mature immune system capable of protecting the preterm infant against severe neonatal infections.

Enteroviral meningoencephalitis in immunocompromised children after matched unrelated donor-bone marrow transplantation

Two children are described who presented with fever and generalized seizures, days 50 and 200, respectively, after matched unrelated donor-bone marrow transplantation. Upon antiepileptic treatment the seizures vanished but somnolence and fever remained. Magnetic resonance imaging (MRI) of the brain was performed and revealed transient asymmetric multifocal hyperintense lesions. Seizures were considered related to infection, and the cyclosporin A (CsA) treatment was not interrupted. Enterovirus was detected by reverse transcriptase-polymerase chain reaction in the spinal fluid of one patient and in the sputum of the other. Both children recovered completely within the next weeks without neurological sequel. This report shows that enteroviral meningoencephalitis can present with seizures during the post-transplant period. It highlights the importance of MRI for neuroimaging and of viral infections as differential diagnosis to CsA neurotoxicity.

Electron microscopic and immunohistochemical verification of diagnosis in two archival cases recognized as encephalitis necroticans acuta (ENA) on routine examinations

Two archival cases diagnosed 20 years ago on routine neuropathological methods as Encephalitis Necroticans Acuta (ENA) were investigated in EM and by immunohistochemical methods. The previous diagnosis was confirmed only in one case because Herpes simplex virus was found. In the second case the intracellular inclusions visible in ME corresponded to Measles Virus thus previous diagnosis was changed to SSPE.

Effect of intravenous immunoglobulin on steroid consumption in patients with severe asthma: a double-blind, placebo-controlled, randomized trial

BACKGROUND

There is a significant group of patients with severe asthma who require chronic use of systemic steroids for control of their disease. These patients are at risk for severe side effects from oral steroids. Intravenous immunoglobulin (IVIG) has immunomodulatory properties, and a few open-label trials have suggested its possible benefit in individuals with severe asthma.

OBJECTIVE

This study was designed to assess the potential benefit of IVIG as a steroid-sparing agent in patients with severe asthma.

METHODS

Thirty-eight immunocompetent steroid-requiring patients with severe asthma were randomly enrolled in a double-blind, placebo-controlled trial of IVIG.

RESULTS

Of the 38 patients enrolled, 28 patients completed the study. A significant reduction in oral steroid requirement was observed in both the IVIG-treated (n = 16) and the placebo-treated (n = 12) patients. Further exploration of the results showed that IVIG, but not placebo, had a significant steroid-sparing effect in patients requiring high doses of oral steroids (ie, >2000 mg in the year before the study). Within this subgroup, IVIG treatment (n = 9) resulted in a significant decrease in oral steroid requirement, with a median of 16.4 mg/day during the pretreatment period to 3 mg/day during the treatment phase (P =. 0078). No significant decrease in oral steroid requirement was observed in placebo-treated patients (n = 8) within this subgroup. Objective and subjective parameters of the patients' asthma were unchanged in spite of the steroid tapering achieved in the group treated with IVIG.

CONCLUSION

IVIG may be a useful steroid-sparing agent in patients with severe asthma requiring high doses of oral steroids.

Defective self-reactive antibody repertoire of serum IgM in patients with hyper-IgM syndrome

We have analyzed the self-reactive repertoires of IgM and IgG Abs in the serum of 19 patients with hyper-IgM syndrome (HIM) by means of a quantitative immunoblotting technique that allows for a quantitative comparison of Ab repertoires in health and disease by multiparametric statistical analysis. Normal tissue extracts of liver, lung, stomach, and kidney were used as sources of self Ags. Extracts of Pseudomonas aeruginosa and Staphylococcus epidermidis were used as sources of nonself Ags. We demonstrate a significant bias in repertoires of reactivities of IgM of patients with HIM with self Ags. Ab repertoires of IgM toward nonself Ags did not differ, however, between patients and controls. No difference was found between IgM repertoires of untreated patients and those of patients receiving substitutive treatment with i.v. IgG. IgG in the serum of HIM patients lacked reactivity with self Ags, although it exhibited a pattern of reactivity with nonself Ags that was similar to that of IgG of healthy controls. The data demonstrate that functional CD40-CD40 ligand interactions are essential for the selection of natural self-reactive B cell repertoires.

Role of preimmunization virus sequences in cellular immunity in HIV-infected patients during HIV type 1 MN recombinant gp160 immunization

The effect of patient preimmunization virus sequences on CTL responses during gp160 immunization were studied. Ten HLA-A2+, HIV+ asymptomatic patients with CD4+ T cells >500/mm3 were given two courses of HIV-1 MN rgp160 vaccine over a 2-year period. Envelope epitope-specific CTL responses, using PBMCs, were measured against peptide-coated autologous B lymphoblastoid cell lines. Optimum CTL epitopes were determined by HLA-A2-binding affinity of 9- to 10-mer peptides containing the HLA-A2.1-binding motif. Ten of the high- or intermediate-binding peptides were conserved among >50% of reported clade B HIV strains. These peptide-specific CTL activities and the patient virus sequences in peptide-coding regions were monitored. Six patients showed envelope peptide-specific CTL responses, which correlated with the presence of whole envelope antigen-specific CTL responses. Five of these patients, who showed responses to epitopes in the gp41 region (aa 814-824), had preimmunization virus similar to the vaccine sequence in this region. Three patients who did not show these epitope-specific responses had initially different sequences in the HIV gene encoding that region. The epitope-specific CTL responses appear to reflect recall responses, as only patients infected with virus containing the vaccine sequence developed them and they could be recalled with a second set of vaccine injections. This appears to be reminiscent of the concept of T cell "original antigenic sin." This vaccine was also immunogenic as measured by gp160-specific lymphocyte-proliferative responses. However, increased immune responses did not impact the HIV load or CTL epitope sequences during therapy.

A pilot clinical trial of HIV antigen-pulsed allogeneic and autologous dendritic cell therapy in HIV-infected patients

A pilot study was carried out to assess the safety and antigen-presenting properties of allogeneic or autologous dendritic cells (DCs) in six HLA-A2+, HIV-infected patients. Allogeneic DCs obtained from the peripheral blood of HLA-identical, HIV-seronegative siblings were pulsed with recombinant HIV-1 MN gp160 or synthetic peptides corresponding to HLA-A2-restricted cytotoxic epitopes of envelope, Gag, and Pol proteins. The antigen-pulsed cells were infused intravenously six to nine times at monthly intervals and HIV-specific immune responses were monitored. One allogeneic DC recipient with a CD4+ T cell count of 460/mm3 showed increases in envelope-specific CTL- and lymphocyte-proliferative responses, as well as in IFN-gamma and IL-2 production. Another allogeneic DC recipient with a CD4+ T cell count of 434/mm3 also showed an increase in HIV envelope-specific lymphocyte-proliferative responses. A recipient of autologous DCs with a CD4+ T cell count of 730/mm3 showed an increase in peptide-specific lymphocyte-proliferative responses after three infusions. Three other allogeneic DC recipients with CD4+ T cell counts <410/mm3 did not show increases in their HIV-specific immune responses. No clinically significant adverse effects were noted in this study and CD4+ T cell numbers and plasma HIV-1 RNA detected by RT-PCR of all six patients were stable during the study period. Thus, both allogeneic and autologous DC infusions were well tolerated and in patients with normal or near normal CD4+ T cell counts administration of these antigen-pulsed cells enhanced the immune response to HIV. However, since no effect on viral load was observed there was no evidence that this approach provided clinical benefit.

Hodgkin's disease developing after spontaneous remission of chronic lymphocytic leukemia

We present a 71-year-old patient with chronic lymphocytic leukemia diagnosed 27 years ago. Initially, the disease was staged as Rai II and the patient suffered from secondary immunoglobulin deficiency. Nevertheless, no treatment was necessary at that time. Because of disease progression a single course of chemotherapy was given in 1984. During the following year there was a constant decline of the WBC, accompanied by normalization of the immunoglobulins; both have remained stable ever since that time. However, there was still residual bone marrow infiltration, indicating persisting CLL. In 1993 cervical lymphadenopathy occurred with acute onset. A diagnostic lymphadenectomy revealed Hodgkin's disease of the nodular-sclerosing subtype. The patient was staged as II-III according to the Ann Arbor Classification and underwent radiation therapy. Cytogenetic examination of the bone marrow revealed a normal karyotype with an inversion of chromosome 9. This case demonstrates the rate coincidence of two lymphoproliferative disorders in the same patient. The clinical course and the immunologic findings of this patient are presented, together with a review of the literature.

Reduced mitogenic stimulation of peripheral blood mononuclear cells as a prognostic parameter for the course of breast cancer: a prospective longitudinal study

Immunosuppression has been often associated with the course of malignant diseases. In the present study, the proliferation of peripheral blood mononuclear cells (PBMCs) in response to mitogenic stimulation with phytohaemagglutinin (PHA) was assessed prospectively in 90 patients with stage I-III breast cancer. Whereas PHA-induced proliferation of PBMCs derived from patients with breast cancer preoperatively was significantly decreased when compared with data obtained in healthy control individuals (P < 0.001), the degree of the defect in PHA-induced proliferation of PBMCs depended upon the tumour burden as manifested by tumour size and axillary lymph node involvement (P < 0.003 in each case). PHA-induced proliferation of PBMCs dropped significantly in patients who received adjuvant chemotherapy consisting of cyclophosphamide, methotrexate and fluorouracil (CMF) after an observation period of 6 months (P < 0.01), but not in patients under adjuvant treatment with tamoxifen only. After an additional 6 months (i.e. 12 months after surgery), PHA-induced proliferation of PBMCs was similar in patients after adjuvant chemotherapy with CMF and in those receiving continued adjuvant tamoxifen treatment (P > 0.1), but in all patients still significantly decreased as compared with healthy controls (P < 0.001). When data obtained preoperatively and after 12 months were compared, it was found that out of 23 patients whose PBMCs had experienced a drop in their PHA-induced proliferation, 14 (61%) had developed metastatic disease within the subsequent 24 months (i.e. 36 months after surgery). In contrast, out of 59 patients whose PBMCs showed an increase in their PHA-induced proliferation within the first 12 months after surgery, only one (2%) presented with disease progression. We thus conclude that PHA-induced proliferation of PBMCs derived from patients with breast cancer depends upon the tumour load and is a good clinical predictor for the further course of the disease.

HIV-1 recombinant gp160 vaccine given in accelerated dose schedules. NIAID AIDS Vaccine Clinical Trials Network

The purpose of this randomized, double-blind study was to test the safety and immunogenicity of an HIV-1LAI recombinant gp160 (rgp160) vaccine in healthy, uninfected volunteers using accelerated dosing schedules. Thirty volunteers were randomly assigned to receive 50-micrograms doses of rgp160 in one of two immunization schedules. Group 1 received rgp160 at times 0, 1, 2 and 5 months; and group 2 received rgp160 at times 0, 1, 2, 3 and 4 months. The vaccine was safe and stimulated high levels of HIV-1 envelope-specific binding antibody and T cell memory. There was a trend (P < 0.10) suggesting neutralizing antibodies were better induced by the regimen incorporating a rest period before the final immunization in group 1 volunteers. Both accelerated immunization schedules induced immune responses at levels similar to or better than those achieved by four rgp160 vaccine injections given over 12-18 months in other studies.

Growth kinetics of fibroblasts on bovine dentin

In vitro dentin barrier tests published so far show several shortcomings. Therefore, we designed a new test method using bovine dentin disks on which cells were grown on one side. In this study, we evaluated the growth kinetics of L-929 mouse fibroblasts on dentin disks of 0.75-mm thickness and 4-mm diameter derived from lower incisors of freshly slaughtered bovines. The application of 50% citric acid for 30 s was optimal for the gentle removal of the smear layer from the cut dentin slices. Growth kinetics of mouse fibroblasts depended on the initially plated cell density: optimal cell growth on the disks was observed with approximately 200 cells/mm2, which was the same as the growth rate on the bottom of a cell culture vessel. Consequently, bovine dentin disks are a suitable substrate for normal cell growth, and this set-up can be used in a dentin barrier test.

Determination of placental ferritin-positive peripheral lymphocytes in early stages of breast cancer

"Ferritin-blocked lymphocytes" or placental ferritin (PLF) -positive T cells have repeatedly been described in the circulation of patients with female breast cancer. Since a monoclonal antibody directed against PLF became available, a study was performed to evaluate its usefulness in an easily reproducible system. One hundred patients with controversial or highly suspicious findings on mammography who subsequently underwent operation entered this trial. Sixty-one healthy blood donors served as controls. Patients with early (lymph-node negative) stages of breast cancer (in situ and T1N0 tumors) revealed significantly higher numbers of PLF-positive cells (9.00% +/- 4.5% and 6.21% +/- 3.4%) as compared with controls or patients with benign lumps (p < 0.001). Patients with negative lymph nodes differed significantly from node-positive patients (9.79% versus 2.55%; p < 0.001), whereas no difference as related to menopausal and estrogen-receptor status was observed. In order to define the sensitivity and specificity of this test, we analyzed four different cutoff levels (3%, 4%, 5%, and 6% of PLF-positive T cells). At a level of PLF-positive lymphocyte cells of 4%, 94% of cancer patients with stage T1N0 disease or ductal carcinoma in situ, 5% of patients with benign lumps, and 7% of healthy controls were identified. Furthermore, 88% of all lymph node-negative cancer patients had more than 4% positive cells, compared with only 25% in patients with axillary node involvement. The fact that more than 90% of all patients with in situ carcinomas and patients with stage T1N0 cancer had values above 4% offers promising aspects for this method to be used to complement mammography in the early detection of breast cancer.

Determination of placental ferritin (PLF)-positive lymphocytes in women in early stages of breast cancer

Previous studies have proved that a certain acidic isoform of ferritin is specifically synthesized by the placenta and breast-cancer tissue. In this context it has been further reported that the determination of this so-called placental isoferritin (PLF) on the surface of a subset of peripheral lymphocytes is highly specific and sensitive for early stage breast cancer. By use of the monoclonal antibody CM-H-9 and flow cytometry, the levels of placental ferritin (PLF)-positive cells were determined in 133 female patients undergoing surgical excision of a controversial or highly suspicious lesion of the breast detected by mammography. In addition, 61 healthy blood donors served as controls. Values of PLF-positive cells in breast cancer patients differed significantly from those found in women with benign diseases and healthy controls (3.87% vs. 1.55% and 2.02, respectively; p less than 0.00001). Analysis of prognostic factors in breast cancer patients (tumor size, lymph-node status, menopausal status, estrogen receptor status, histologic grading and grading subfactors) revealed significantly higher levels of PLF-positive cells in lymph-node-negative patients compared with node-positive patients (p less than 0.00001). Furthermore, levels of PLF-positive cells showed a significantly negative correlation with tumor size and nuclear polymorphism. In 15 patients who underwent a guide-wire-directed surgical biopsy for a non-palpable, mammographically suspect lesion, 4 cases of cancer correlated with high values of PLF-positive lymphocytes while only 1 patient with a benign histologic result exhibited more than 4% positive cells.

[Growth hormone therapy in STH deficiency with immunologic deficiency and chromosome fragility]

A 8 year old boy with short stature, low height velocity, mental retardation, cutaneous abnormalities, common variable immunodeficiency and increased chromosomal instability is described. In this patient growth hormone deficiency could be demonstrated by several stimulation tests. Growth hormone treatment increased growth rate from 4 cm/year before therapy to 7.8 cm in the first and 7.1 cm in the second year of treatment. Under therapy no effect on the immunological reactivity could be observed.

An HLA-DR alpha promoter DNA-binding protein is expressed ubiquitously and maps to human chromosomes 22 and 5

The class II major histocompatibility complex antigens are a family of integral membrane proteins whose expression is tissue-specific and developmentally regulated. Three consensus sequences, X1, X2, and Y, separated by an interspace element, is found upstream from all class II genes. Deletion of each of these sequences eliminates expression of class II genes in vitro or in transgenic mice. Here we further characterize the expression of a cDNA encoding a DNA binding protein (human X-box binding protein, hXBP-1) which, like the proteins in whole nuclear extract, recognizes both the X2 promoter element of the human DR alpha and DP beta and mouse A alpha genes. The hXBP-1 cDNA hybridizes to human RNA species of approximately 2.2 kilobases (kb) and 1.6 kb, which are expressed in class II negative as well as class II positive cells. hXBP-1 transcripts are present in several class II deficient mutant B cell lines, although in one such line, 6.1.6, levels were somewhat reduced. Chromosome mapping studies demonstrate that hXBP-1 arises from a small gene family, two of whose members map to human chromosomes 5 and 22. Taken together, these data suggest a high degree of complexity in the transcriptional control of the class II gene family.

[Clinico-immunologic aspects of IgG subclass deficiency]

Serum IgG contains 4 subclasses, IgG1 (60-66%), IgG2 (20-30%), IgG3 (less than or equal to 5%) and IgG4. Individual subclasses vary with respect to their physicochemical and biological properties. IgG subclass concentrations in serum are age dependent. IgG1 and IgG3 reach near to adult levels around the age of 3, IgG2 and IgG4 after the age of 6. Antibodies of certain specificities generally belong to a certain isotype (subclass) due to the isotype restriction. Patients with subclass deficiencies often suffer from recurrent infections. Those with IgG2 deficiency coften occurring with IgA and IgG4 deficiency) develop recurrent infection of the upper and lower respiratory tract often caused by pyogenic microorganisms (Haemophilus, Pneumo-(occus). Since early initiation of IVIG substitution therapy has a beneficial effect on long term prognosis the importance of early diagnosis is apparent.

Large-scale production and purification of a vaccinia recombinant-derived HIV-1 gp160 and analysis of its immunogenicity

The human immunodeficiency virus (HIV-1) envelope gene was expressed in large-scale microcarrier cultures of Vero cells using a system involving coinfection with two recombinant vaccinia viruses. One recombinant contained the bacteriophage T7 RNA polymerase gene under control of a vaccinia virus promoter. The second contained the HIV-1 gp160 gene flanked by T7 promoter and termination sequences. The protein was expressed on the surface of infected cells, and it was shown to have a molecular weight of 160 kD and to react with gp41 and gp120 specific monoclonal antibodies. After purification by successive affinity and ion-exchange chromatography, the protein was demonstrated to be present in a particulate form with a diameter in the range of 15-30 nm. When injected into goats a high-titer gp160 specific antibody response was elicited and group-specific neutralizing activity could be demonstrated in vitro. The immunogenicity of the protein was also studied in conjunction with a number of adjuvant formulations, and the highest potency in mice was obtained using a preparation with 0.2% Al(OH)3 and 0.25% deoxycholate.

[Results of the treatment of children with brain neoplasms. I. Survival of children and cause of death]

In a group of 146 children aged from 8 months to 16 years treated for brain neoplasms the authors analysed the therapeutic results. Excluding the so called operative losses the survival over 4 years was obtained in one-fourth of patients with medulloblastoma, in over one-third of those with ependymoma, one-half of astrocytoma cases, and over one-third of children with other neoplasms. The authors estimate positively the therapeutic methods used (operation, radiotherapy and chemotherapy by Bloom's schedule) and see the possibility of increasing the survival rate by improvement in the diagnosis of brain tumours in children and by optimalization of treatment, especially in its early period, for reducing the number of operative losses.

[Parameters of cellular and humoral immunity in patients with severe acne]

Severe forms of acne, characterized by predominance of inflammatory reactions and persistence of the disease for years, still present therapeutic problems. The purpose of our study was to investigate the role of the immune system in severe persisting forms of acne by means of determination of cellular and humoral immunobiological parameters. The study was performed on 52 patients (47 males and 5 females) having suffered from severe acne for six years on an average, including papulopustular acne grade IV resistant to therapy, nodulocystic acne, conglobate acne, and acne tetrade. The results were compared with those of 52 healthy controls of the same age showing no inflammatory diseases, who were tested on the same day. In 56% of the acne patients, one or more parameters showed pathological values, while in nodulocystic and conglobate acne there were similar results with regard to cellular defects and acute phase reactants. The lymphocytic proliferation induced by mitogens was significantly decreased in 35% of the acne patients. We assume that the immunodeficiency observed in these patients may be mainly secondary; however, it may contribute to the perpetuance of the disease and its resistance to therapy.

[The septic state in infancy]

In a retrospective study it was investigated in which a course the septicemia appears during the first year of life and which laborchemical and immunological findings are typical for the specific manifestation and can be used for the diagnosis. 27 sucklings with septicemia were admitted at our hospital during 1976-1982. As the clinical course we found: the acute septicemia with pronounced shocksymptoms (Septic-Toxic-Course, STC), the septicemia with a tardy course and hematogenous dispersion of bacteria in one organsystem, namely in the brain (Meningoencephalitis), in the bone (Osteomyelitis) and in the soft tissue (Phlegmon), the septicemia with a tardy course and forms a septicopyemia with secundary dispersion of bacteria in multiple organsystems. Only STC and septicopyemia show the symptoms which are lead back with the dispersion of bacteria. By the septicemia with a tardy course and hematogenous dispersion of bacteria in one organsystem the clinical symptoms are determined only in the infected organ. As the only course of septicemia the STZ shows laborchemically in the blood a damage to the livercells with a constant elevated levels of plasmaencyms GOT, GPT and LDH; this findings can be used for a diagnostic criterion. By septicopyemia, meningitis and osteomyelitis the findings of sepsis exist in the blood but are rare by phlegmon. By septicemia with a tardy course (2, 3) a humoral and/or cellular immundeficiency exist. This is a point of application for therapy to give biological antibody with a large spectrum.