Experimental validation of an inverse method for defect reconstruction in a two-dimensional waveguide model.

Defect reconstruction is essential in non-destructive testing and structural health monitoring with guided ultrasonic waves. This paper presents an algorithm for reconstructing notches in steel plates, which can be seen as artificial defects representing cracks by comparing measured results with those from a simulation model. The model contains a parameterized notch, and its geometrical parameters are to be reconstructed. While the algorithm is formulated and presented in a general notation, a special case of guided wave propagation is used to investigate one of the simplest possible simulation models that discretizes only the cross section of the steel plate. An efficient simulation model of the plate cross section is obtained by the semi-analytical scaled boundary finite element method. The reconstruction algorithm applied is gradient-based, and algorithmic differentiation calculates the gradient. The dedicated experimental setup excites nearly plane wave fronts propagating orthogonal to the notch. A scanning laser Doppler vibrometer records the velocity field at certain points on the plate surface as input to the reconstruction algorithm. Using two plates with notches of different depths, it is demonstrated that accurate geometry reconstruction is possible.

A Multielectrode Nerve Cuff for Chronic Velocity Selective Recording in a sheep model.

Supra-sacral spinal cord injury (SCI) causes loss of bladder fullness sensation and bladder over-activity, leading to retention and incontinence respectively. Velocity selective recording (VSR) of nerve roots innervating the bladder might enable identification of bladder activity. A 10-electrode nerve cuff for sacral nerve root VSR was developed and tested in a sheep model during acute surgeries and chronic implantation for 6 months. The cuff performed well, with 5.90±1.90 kΩ electrode, and <~800 Ω tissue impedance after 189 days implantation with a stable device and tissues. This is important information for assessing the feasibility of chronic VSR.Clinical Relevance-This demonstrates the manufacturing and performance of a neural interface for chronic monitoring of bladder nerve afferents with applications in urinary incontinence and retention management following SCI.

Pediatric head and neck manifestations associated with multiple endocrine neoplasia syndromes.

INTRODUCTION: Multiple endocrine neoplasia (MEN) syndromes are a group of hereditary cancer syndromes that can predispose children to endocrine neoplasms developing within the head and neck. OBJECTIVE: To examine the neoplastic manifestations of MEN type 1 (MEN1) and MEN type 2 (MEN2) in the pediatric head and neck. METHODS: Single-institution, retrospective review of pediatric MEN between 2005 and 2022. RESULTS: Fifty-three children were genetically confirmed with MEN (15 MEN1, 34 MEN2A, and 4 MEN2B), while three patients received clinical diagnoses of MEN1. The male to female ratio was essentially equal (1.15:1), and a documented family history of cancer was present in 89% (50/56). After multidisciplinary evaluation, a familial MEN diagnosis was confirmed in 91% (51/56). The mean ages of initial presentation and surgical intervention were 8.9 years (SD 5) and 9.8 years (SD 4.8), respectively. Although patients with MEN2 received surgery earlier than patients with MEN1 (8.7 vs 12.7 years), surgical patients with MEN2 in this cohort were older relative to current American Thyroid Association (ATA) guidelines primarily due to late presentation. Thyroid malignancies were identified in 36% (9/25) of thyroidectomy specimens (21 MEN2A, 4 MEN2B), with medullary thyroid carcinoma (MTC) present in five MEN2A patients and three MEN2B patients (89%), and papillary thyroid carcinoma (PTC) present in one MEN2A patient (11%). Nearly 90% (8/9) of thyroid malignancies were occult, with some occurring earlier than predicted by current guidelines (ATA-MOD and ATA-H). Central neck dissections were performed in 24% (2 MEN1, 2 MEN2A, and 4 MEN2B), with two MEN2B (50%) demonstrating cervical lymph node (LN) metastases. Additional histopathologic findings included C-cell hyperplasia in 57% (12/21) of MEN2A thyroidectomy patients. Of the eight MEN1 parathyroidectomy patients, four demonstrated parathyroid hyperplasia and four presented with parathyroid adenoma. CONCLUSION: Nearly 60% required head and neck procedures. While MEN1 guidelines were appropriate for our cohort, we identified patients with MEN2 that developed MTC earlier than expected based on current ATA guidelines, including children in categories considered lower risk. In conjunction with a multidisciplinary approach, pediatric head and neck surgeons should be aware of the potential need for earlier surgical intervention in the pediatric MEN2 population.

Defect reconstruction in a two-dimensional semi-analytical waveguide model via derivative-based optimization.

This paper considers an indirect measurement approach to reconstruct a defect in a two-dimensional waveguide model for a non-destructive ultrasonic inspection via derivative-based optimization. The propagation of the mechanical waves is simulated by the scaled boundary finite element method that builds on a semi-analytical approach. The simulated data are then fitted to given data associated with the reflected waves from a defect which is to be reconstructed. For this purpose, we apply an iteratively regularized Gauss-Newton method in combination with algorithmic differentiation to provide the required derivative information accurately and efficiently. We present numerical results for three kinds of defects, namely, a crack, delamination, and corrosion. The objective function and the properties of the reconstruction method are investigated. The examples show that the parameterization of the defect can be reconstructed efficiently as well as robustly in the presence of noise.

Congenital Nasal Pyriform Aperture Stenosis: Evidence of Premature Fusion of the Midline Palatal Suture.

BACKGROUND AND PURPOSE: Various etiologies have been theorized for the development of congenital nasal pyriform aperture stenosis (CNPAS). Imaging possibly implicates abnormal fusion of the midline palatal suture and deficient lateral growth of the midface in affected neonates. MATERIALS AND METHODS: A single-center, retrospective study was performed at a tertiary care pediatric hospital involving neonates and infants between 0 and 90 days of life. Maxillofacial CT scans of patients were reviewed. Abnormality of the palatal suture and midface transverse dimensions were measured and analyzed in patients with and without CNPAS. RESULTS: A total of 109 patients between 0 and 90 days of life had maxillofacial CT scans. Thirteen patients were classified as having CNPAS, 27 patients had normal scans (control group), and 69 patients were excluded because of the presence of other craniofacial anomalies. All patients with CNPAS had evidence of abnormal fusion of the midline palatal suture. Zero patients without CNPAS had a midline palatal suture abnormality. The mean widths of the pyriform aperture were 5.7 mm (SD, 1.7) in the CNPAS group and 13.1 mm (SD, 2.7) in the control group (P < .0001). The mean distance between the superior portions of the nasolacrimal ducts was 9.1 mm (SD, 2.1) in the CNPAS group, and the mean of the control group was 13.4 mm (SD, 2.2) (P < .0001). CONCLUSIONS: Patients with CNPAS have abnormal fusion of the midline palatal suture and exhibit lateral growth restriction of the midface. This may implicate synostosis of the midline palatal suture and abnormal midface growth.

Non-accidental trauma presenting with nasal septal hematoma or abscess.

OBJECTIVES: Failure to diagnose non-accidental trauma (NAT) leaves the victim at risk of further injury or even death. It is incumbent upon physicians and other health care personnel to identify trauma patterns that have a high likelihood of being caused by NAT. The objective of this study is to discuss the presentation of nasal septal hematoma (NSH) or nasal septal abscess (NSA) as a sign of NAT. METHODS: This is a retrospective case series of patients presenting with nasal septal hematoma or abscess between 2010 and 2019. The primary endpoint was the etiology of the injury. Secondary endpoints included demographics, concomitant injuries and treatments rendered. RESULTS: There were 28 patients who presented with septal hematoma or abscess. The etiologies included 20 (71.4%) due to accidental trauma, four (13.8%) with NAT, one infectious, and three unknown. All four NAT patients were male and infants with an average age of 5.4 months (SD 4.6) significantly (p = 0.0069) younger than 10.3 years (SD 5.1) in the accidental trauma group. There was a delayed time to presentation for the NAT patients compared to other etiologies. Two of four NAT patients were initially thought to have a congenital midline nasal dermoid, yet surgical intervention revealed a hematoma. Further NAT evaluation noted concomitant injuries including rib fractures and intracranial injuries in 75% of the NAT patients. CONCLUSIONS: Presentation of a child with NSH/NSA prior to the onset of ambulation or with a delayed time to presentation should prompt suspicion and further workup for NAT.

The Effects of the Presence of Multiple Conduction Velocities in the Analysis of Electrically-Evoked Compound Action Potentials (eCAPs).

New methods for the analysis of electrically-evoked compound action potentials (eCAPs) are described. Mammalian nerves tend to have broad multi-modal distributions of fibre diameters, which translates into a spread of conduction velocities. The method of velocity selective recording (VSR) is unable to distinguish between this spectral spread and the transfer function of the system. The concept of the velocity impulse function (VIF) is introduced as a tool to differentiate between these signal and system attributes. The new methods enable separate estimates of velocity spectral broadening and signal-to-noise ratio (SNR) to be obtained.

Selective Recording of Urinary Bladder Fullness from the Extradural Sacral Roots.

Managing the urinary bladder is of primary importance to clinicians and patients after trauma to the spinal cord. Sacral Anterior Root Stimulators that control the bladder have been available as clinical technology for many years, however these devices cannot measure the fullness of the urinary bladder or detect the onset of reflex voiding. In order to address this fundamental limitation, it is necessary to develop a method for recording the neural signals that encode bladder fullness. This paper presents a proof of concept technique for recording bladder afferents from the extradural sacral roots using a multiple electrode cuff. Results are provided from acute in-vivo experiments performed in sheep.

Influence of thermodynamic properties of a thermo-acoustic emitter on the efficiency of thermal airborne ultrasound generation.

In this work we experimentally verify the theoretical prediction of the recently published Energy Density Fluctuation Model (EDF-model) of thermo-acoustic sound generation. Particularly, we investigate experimentally the influence of thermal inertia of an electrically conductive film on the efficiency of thermal airborne ultrasound generation predicted by the EDF-model. Unlike widely used theories, the EDF-model predicts that the thermal inertia of the electrically conductive film is a frequency-dependent parameter. Its influence grows non-linearly with the increase of excitation frequency and reduces the efficiency of the ultrasound generation. Thus, this parameter is the major limiting factor for the efficient thermal airborne ultrasound generation in the MHz-range. To verify this theoretical prediction experimentally, five thermo-acoustic emitter samples consisting of Indium-Tin-Oxide (ITO) coatings of different thicknesses (from 65 nm to 1.44 µm) on quartz glass substrates were tested for airborne ultrasound generation in a frequency range from 10 kHz to 800 kHz. For the measurement of thermally generated sound pressures a laser Doppler vibrometer combined with a 12 µm thin polyethylene foil was used as the sound pressure detector. All tested thermo-acoustic emitter samples showed a resonance-free frequency response in the entire tested frequency range. The thermal inertia of the heat producing film acts as a low-pass filter and reduces the generated sound pressure with the increasing excitation frequency and the ITO film thickness. The difference of generated sound pressure levels for samples with 65 nm and 1.44 µm thickness is in the order of about 6 dB at 50 kHz and of about 12 dB at 500 kHz. A comparison of sound pressure levels measured experimentally and those predicted by the EDF-model shows for all tested emitter samples a relative error of less than ±6%. Thus, experimental results confirm the prediction of the EDF-model and show that the model can be applied for design and optimization of thermo-acoustic airborne ultrasound emitters.

Regulation of alternative VEGF-A mRNA splicing is a therapeutic target for analgesia.

Vascular endothelial growth factor-A (VEGF-A) is best known as a key regulator of the formation of new blood vessels. Neutralization of VEGF-A with anti-VEGF therapy e.g. bevacizumab, can be painful, and this is hypothesized to result from a loss of VEGF-A-mediated neuroprotection. The multiple vegf-a gene products consist of two alternatively spliced families, typified by VEGF-A165a and VEGF-A165b (both contain 165 amino acids), both of which are neuroprotective. Under pathological conditions, such as in inflammation and cancer, the pro-angiogenic VEGF-A165a is upregulated and predominates over the VEGF-A165b isoform. We show here that in rats and mice VEGF-A165a and VEGF-A165b have opposing effects on pain, and that blocking the proximal splicing event - leading to the preferential expression of VEGF-A165b over VEGF165a - prevents pain in vivo. VEGF-A165a sensitizes peripheral nociceptive neurons through actions on VEGFR2 and a TRPV1-dependent mechanism, thus enhancing nociceptive signaling. VEGF-A165b blocks the effect of VEGF-A165a. After nerve injury, the endogenous balance of VEGF-A isoforms switches to greater expression of VEGF-Axxxa compared to VEGF-Axxxb, through an SRPK1-dependent pre-mRNA splicing mechanism. Pharmacological inhibition of SRPK1 after traumatic nerve injury selectively reduced VEGF-Axxxa expression and reversed associated neuropathic pain. Exogenous VEGF-A165b also ameliorated neuropathic pain. We conclude that the relative levels of alternatively spliced VEGF-A isoforms are critical for pain modulation under both normal conditions and in sensory neuropathy. Altering VEGF-Axxxa/VEGF-Axxxb balance by targeting alternative RNA splicing may be a new analgesic strategy.

Association of white matter hyperintensities with low serum 25-hydroxyvitamin D levels.

BACKGROUND AND PURPOSE: Vitamin D deficiency is associated with cognitive impairment in the elderly and with increased white matter T2 hyperintensities in elderly debilitated patients. We investigated the relationship between serum vitamin D and brain MR findings in adult outpatients. MATERIALS AND METHODS: Brain MR studies of 56 patients ages 30-69 years were selected when vitamin D level had been obtained within 90 days of the MRI. White matter T2 hyperintensities were characterized by size and location by two neuroradiologists. Manual volumetric analysis was assessed in patients more than 50 years of age. RESULTS: The entire cohort showed a significant negative relationship between serum 25-hydroxyvitamin D and the number of confluent juxtacortical white matter T2 hyperintensities (P = .047). The cohort ages 50 years and older showed stronger correlation between confluent white matter T2 hyperintensities and serum 25-hydroxyvitamin D in the juxtacortical region; number (P = .015) and size of white matter T2 hyperintensities (P = .048). Atrophy was not significantly related to serum 25-hydroxyvitamin D by radiologist visual analysis or by the bicaudate ratio. CONCLUSIONS: We found a significant relationship between vitamin D and white matter T2 hyperintensities in independent adult outpatients, especially over the age of 50 years.

Ultrasonic field profile evaluation in acoustically inhomogeneous anisotropic materials using 2D ray tracing model: Numerical and experimental comparison.

Ultrasound propagation in inhomogeneous anisotropic materials is difficult to examine because of the directional dependency of elastic properties. Simulation tools play an important role in developing advanced reliable ultrasonic non destructive testing techniques for the inspection of anisotropic materials particularly austenitic cladded materials, austenitic welds and dissimilar welds. In this contribution we present an adapted 2D ray tracing model for evaluating ultrasonic wave fields quantitatively in inhomogeneous anisotropic materials. Inhomogeneity in the anisotropic material is represented by discretizing into several homogeneous layers. According to ray tracing model, ultrasonic ray paths are traced during its energy propagation through various discretized layers of the material and at each interface the problem of reflection and transmission is solved. The presented algorithm evaluates the transducer excited ultrasonic fields accurately by taking into account the directivity of the transducer, divergence of the ray bundle, density of rays and phase relations as well as transmission coefficients. The ray tracing model is able to calculate the ultrasonic wave fields generated by a point source as well as a finite dimension transducer. The ray tracing model results are validated quantitatively with the results obtained from 2D Elastodynamic Finite Integration Technique (EFIT) on several configurations generally occurring in the ultrasonic non destructive testing of anisotropic materials. Finally, the quantitative comparison of ray tracing model results with experiments on 32mm thick austenitic weld material and 62mm thick austenitic cladded material is discussed.

[Antibodies against vaccine-preventable diseases in pregnant women and their offspring. Measles, mumps, rubella, poliomyelitis, and varicella]. / Antikörper gegen impfpräventable Erkrankungen bei Schwangeren und deren NeugeborenenMasern, Mumps, Röteln, Poliomyelitis, Varizellen.

In the eastern part of Germany, the age of primigravid women has clearly increased since 1990. This may change the protection provided by antibodies in pregnant women as well as their newborns. The objective of the present study was to assess antibodies against vaccine-preventable viral infectious diseases in pregnant women and their offspring to draw conclusions about their protection. Maternal and cord blood samples of 290 women from the eastern part of Germany with a mean age of 28 years were analyzed for antibodies against measles, mumps, rubella, poliomyelitis, and varicella. The study showed that the pregnant women had detectable levels of antibodies against measles virus in 79%, against mumps virus in 96%, against rubella virus in 87%, against polioviruses types 1-3 in 62-64%, and against varicella-zoster virus (VZV) in 97% of the cases. The seroprevalence of the antibodies in the newborns were not significantly different from those of their mothers. When antibody titers of mothers and newborns were compared, significantly higher titers to VZV could be detected in the cord blood sera of newborns. It is suggested that the prevalence of antibodies against measles and poliomyelitis is insufficient to protect the newborns efficiently. An immunity gap of 13% against rubella in mothers results in a potential risk for a congenital rubella syndrome in newborns. Despite the high seroprevalence of rubella and chickenpox, there is considerable potential for infections during pregnancy and neonatal period.

[Antibodies against vaccine-preventable diseases in pregnant women and their offspring. Diphtheria, pertussis, tetanus]. / Antikörper gegen impfpräventable Erkrankungen bei Schwangeren und deren NeugeborenenDiphtherie, Pertussis, Tetanus.

In the eastern part of Germany, the age of primigravid women has increased from the end of the 2nd decade to the second half of the 3rd decade since 1990. This might influence the vaccine-induced immunity in pregnant women as well as their newborns. The objective of the present study was to examine the influence of the higher age of pregnant women on antibody protection. Maternal and cord blood samples of 290 women in the eastern part of Germany with a mean age of 28 years were analyzed for antibodies against the vaccine-preventable diseases diphtheria, pertussis, and tetanus. Compared with the data on vaccination history, the seroprevalence rate of tetanus was significantly enhanced and the seroprevalence rate of diphtheria and pertussis was significantly reduced. Detectable levels of antibodies against tetanus toxin were found in 93% of the mothers, against diphtheria toxin in 70%, and against Bordetella pertussis in 37%. Cord blood samples had a significantly higher prevalence of antibodies against pertussis and diphtheria in comparison to maternal probes. In addition,there were significantly enhanced antibody concentrations against diphtheria toxin in the newborns. In conclusion, the prevalence of antibodies determined suggests they are insufficient for protecting the newborns efficiently against pertussis and diphtheria in spite of the evidence for an active placental antibody transfer.

Antibodies against vaccine-preventable diseases in pregnant women and their offspring in the eastern part of Germany.

Maternal and cord blood samples of 290 pregnant women in the eastern part of Germany with a mean age of 28 years (16-41 years) were analyzed for antibodies to vaccine-preventable diseases. Both mothers and infants had detectable levels of antibodies to mumps in 96% and to tetanus in 93% of cases. Detectable levels to poliomyelitis, diphtheria, measles and rubella varied from 55% to 91%. Cord blood samples had a significantly higher prevalence of antibodies to pertussis (61%) and diphtheria (81%) in comparison to maternal samples (pertussis 37%, diphtheria 70%) as well as significantly enhanced antibody concentrations to diphtheria. In conclusion, the prevalence of antibodies to pertussis (61%), diphtheria (81 %), poliomyelitis (55-59%) and measles (85%) is suggested to be insufficient in newborn infants to protect them against these infectious diseases.

Evaluation of patients for implantable pain modalities: medical and behavioral assessment.

BACKGROUND: Advances in neurobiology serve as the basis for current and evolving implantable pain modalities, consisting of neurostimulation and neuraxial drug administration systems. Appropriate treatment of pain begins with an accurate diagnosis based on thorough physical and behavioral evaluations. MEASURES: The medical evaluation includes a review of the patient's medical history, diagnostic studies, physical examination, complete diagnostic workup, and screening trial of the proposed implantable therapy. The behavioral evaluation includes a review of the patient's history and medical records, clinical interview, mental status examination, psychological testing, and determination of suitability for implantation. CONCLUSIONS: Patients with chronic pain are subject to neurophysiological, emotional, and behavioral influences that govern their perception of pain and of pain relief. Therefore, treatment of chronic pain is multidisciplinary, drawing on cognitive and behavioral psychological therapies, functional rehabilitation, orthopedic and neurologic surgery, medications, nerve blockade, neuroaugmentative procedures, and sometimes neurodestructive procedures. Appropriate selection of patients helps ensure that implantable therapies are used for those who are most likely to benefit.

High-b-value diffusion-weighted MR imaging of suspected brain infarction.

BACKGROUND AND PURPOSE: Recent technological advances in MR instrumentation allow acquisition of whole-brain diffusion-weighted MR scans to be obtained with b values greater than 1,000. Our purpose was to determine whether high-b-value diffusion-weighted MR imaging improved contrast and detection of signal changes in acute and chronic brain infarction. METHODS: We prospectively evaluated the MR scans of 30 subjects with a history of possible brain infarction on a 1.5-T MR imager with 40 mT/meter gradients (slew rate 150 T/m/s) by use of the following single-shot echo-planar diffusion-weighted MR sequences: 1) 7,999/ 71.4/1 (TR/TE/excitations, b = 1,000; 2) 999/ 88.1/3, b = 2,500; and 3) 7,999/ 92.1/4, b = 3,000. Diffusion-weighted MR imaging was performed in three orthogonal directions during all sequences. All subjects were scanned with fast fluid-attenuated inversion recovery (FLAIR) (10,006/145/2,200/1 [TR/TE/TI/excitations]) and fast spin-echo T2-weighted (3,650/95/3 [TR/TE/excitations], echo train length, 8). The diagnosis of brain infarction was established by clinical criteria. RESULTS: Twenty women and 10 men with a mean age of 67.7 years were enrolled in the study. One subject was excluded owing to poor image quality. Twelve of 29 subjects had a clinical diagnosis of acute infarction. All 12 had lesions that were hyperintense on diffusion-weighted images at all three b values; five were cortical and seven subcortical. There was increased contrast of all lesions on high-b-value scans (b = 2,500 and 3,000). Lesions that were hypointense on diffusion-weighted images were identified and evaluated at the three different b values. At b = 1,000, there were 19 hypointense lesions, whereas at b = 2,500 and 3,000 there were 48 and 55 lesions, respectively. On FLAIR and T2-weighted images, these low-signal lesions were predominantly chronic, subcortical, ischemic lesions and lacunar infarcts, but four chronic cortical infarcts, one porencephalic cyst, and one primary brain tumor were also found. Low-signal lesions were also noted to have increased contrast on high-b-value diffusion-weighted scans. CONCLUSION: High-b-value diffusion-weighted MR imaging (b = 2,500 or b = 3,000) had no impact on diagnosis of acute infarction. High-b-value diffusion-weighted MR imaging (b = 2,500) combined with diffusion-weighted MR imaging at b = 1,000 improves tissue characterization by increasing the spectrum of observed imaging abnormalities in patients with suspected brain infarction.

Serial CT and MR imaging of carmustine wafers.

BACKGROUND AND PURPOSE: A new option in the treatment of recurrent malignant glioma is surgical placement of chemotherapy-laden biodegradable wafers. We describe the CT and MR appearance of chemotherapy wafers in patients after surgery for recurrent malignant glioma METHODS: Eighteen patients had carmustine (BCNU) wafers implanted during reoperation for malignant glioma; three patients had empty, placebo wafers placed. The 21 patients had a total of 22 CT and 57 MR imaging studies. Repeat CT studies were conducted for up to 6 months, the MR studies for up to 1 year. Examinations were evaluated for attenuation on CT scans, signal abnormalities on MR images, and changing appearance during the follow-up period. Enhancement characteristics were also assessed. RESULTS: On CT scans, 13 of 16 acute (<7 days) cases showed linear high-attenuation wafers, with three showing low attenuation. On MR images, all T1 and T2 studies performed in the acute stage showed decreased signal of the wafers. Eight of 15 studies showed a transient increase in T1 only at about 2 months. Wafers decreased in conspicuity on both CT and MR studies after 2 months. The wafers did not enhance. One postoperative tumor showed a transient increase in edema and increased enhancement at 5 weeks. The presence or absence of BCNU within the wafers did not change their appearance. CONCLUSION: BCNU wafers have a characteristic appearance: in the first 7 days after implantation they are linear, usually of increased attenuation on CT scans, and always show decreased signal on MR images; they do not enhance, and become less conspicuous after 2 months.

Varicella vaccination in children after bone marrow transplantation.

Herpes zoster (HZ) is one of the most common complications after bone marrow transplantation (BMT) in children. Apart from treatment with antiviral drugs, effective prevention by active immunization with varicella-zoster virus (VZV) appears to be possible. In this study 15 patients were vaccinated with a live attenuated VZV vaccine (Varilrix) 12-23 months after BMT. The vaccine was well tolerated without adverse reactions. Chickenpox or HZ were not observed for up to 2 years after immunization. Eight out of nine seronegative patients seroconverted and in six virus-specific IgG could still be demonstrated 2 years later. The incidence of VZV diseases in 133 non-immunized children after BMT was 26.3%. Infections usually occurred within 18 months after BMT.