The immature platelet fraction: creating neonatal reference intervals and using these to categorize neonatal thrombocytopenias.

OBJECTIVE: The immature platelet fraction (IPF) is a laboratory measurement analogous to the reticulocyte count, but reflecting the thrombopoietic state. Similar to a reticulocyte count, it can be expressed as a percent (IPF%=percent of platelets that are immature) or as an absolute number per µl blood; the immature platelet count (IPC=IPF% × platelets per µl of blood). STUDY DESIGN: Using a retrospective analysis of de-identified data from non-thrombocytopenic neonates, we created reference intervals for IPF% and IPC. We then tested the value of these measurements for categorizing thrombocytopenic neonates. RESULTS: New charts display reference intervals for IPF% and IPC on the day of birth according to gestational age, and during the first 90 days after birth. Neonates with hyporegenerative varieties of thrombocytopenias (syndromes, small for gestational age, birth asphyxia) had lower IPF% and IPC than did neonates with consumptive thrombocytopenias (immune-mediated, infection, disseminated intravascular coagulation, necrotizing enterocolitis; both P<0.0001). CONCLUSION: The new reference interval charts can be used to recognize abnormal IPFs. The IPF parameters can help clarify the kinetic mechanism responsible for thrombocytopenias in neonates.

Non-invasive vesicoureteral reflux detection: heating risk studies for a new device.

OBJECTIVE: To investigate a novel non-invasive device developed to warm bladder urine and to measure kidney temperature to detect vesicoureteral reflux. MATERIALS AND METHODS: Microwave antennas focused energy within the bladder. Phantom experiments measured the results. The heating protocol was optimized in an in-vivo porcine model, and then tested once, twice and three times consecutively in three pigs followed by pathologic examinations. RESULTS: Computer simulations showed a dual concentric conductor square slot antenna to be the best. Phantom studies revealed that this antenna easily heated a bladder phantom without over heating intervening layers. In-vivo a bladder heating protocol of 3 min with 30 W each to two adjacent antennas 45 s on 15 s off followed by 15 min of 15 s on and 45 s off was sufficient. When pigs were heated once, twice and three times with this heating protocol, pathologic examination of all tissues in the heated area showed no thermal changes. More intensive heating in the animal may have resulted in damage to muscle fibers in the anterior abdominal wall. CONCLUSIONS: Selective warming of bladder urine was successfully demonstrated in phantom and animals. Localized heating for this novel vesicoureteral reflux device requires low-power levels and should be safe for humans.

Case report: perianal necrotizing fasciitis in a near-term neonate.

Necrotizing fasciitis in the neonatal period is a rare, life-threatening condition. Previous cases of neonatal necrotizing fasciitis in the perianal region were speculated to have been initiated by rectal mucosal trauma secondary to rectal temperature measurements. We observed a case of fatal perianal necrotizing fasciitis in a neonate where the process began as a red ring surrounding the anus and guiac-positive stools, detected after a rectal temperature measurement. We speculate that the perianal necrotizing fasciitis that subsequently developed might have been initiated by a minor rectal mucosal injury, and we investigated the instrument used for the rectal temperature measurement to assess any potential areas on the probe sheath cover that might cause a minor injury. Each probe sheath cover examined had three areas that, in our opinion, could possibly generate a minor mucosal injury.

Response to Shiga toxin-1, with and without lipopolysaccharide, in a primate model of hemolytic uremic syndrome.

Shiga toxin (Stx) and lipopolysaccharide (LPS) both participate in the pathogenesis of post-diarrheal hemolytic uremic syndrome (HUS), yet little is known about the factors that modulate the host response to these toxins. We have previously shown that the baboon develops HUS if 100 ng/kg of purified Stx-1 is administered rapidly as a single bolus, but not if it is given as four 25-ng/kg doses every 12 h. We therefore used this baboon model to study the response to small intravenous doses of Stx-1, with and without the co-administration of LPS. The co-administration of two 1-mg/kg doses of LPS (given at 0 and 24 h) and four 25-ng/kg doses of Stx-1 (given at 0, 12, 24, and 36 h) resulted in HUS, but the administration of either toxin separately did not. The development of HUS was associated with a rise in urinary, but not plasma concentrations of TNF, and a rise in both urinary and plasma concentrations of IL-6 and IL-8. We speculate that LPS is not required for disease expression in the human, but that it can augment the response to otherwise subtoxic amounts of Stx and this augmentation may be mediated by LPS-induced cytokine release.

Therapy associated changes in childhood tumors.

Contemporary treatment regimens for the common solid tumors of childhood have led to increased numbers of post-treatment pathologic specimens from survivors. Current therapeutic strategies for childhood cancers in North America require an accurate pathologic diagnosis and stratify patients based on combinations of clinical, biological, and pathologic features. In several tumor systems, the pathologic response to therapy also modifies the treatment regimen. Accurate pathologic interpretation of such specimens is critical in providing useful prognostic information for therapeutic decisions. Standardized handling of post-therapy pathologic specimens, appropriate use of molecular and genetic studies, consideration of the differential diagnoses, and assessment of the potential biologic significance of therapy-induced pathologic changes are, therefore, critical for patient management and determination of treatment protocols.

Familial Wilms' tumor with neural elements: characterization by histology, immunohistochemistry, and genetic analysis.

Wilms' tumor (WT) is the most common renal malignancy of children. While most occur sporadically, a small percentage are familial or occur as part of a developmental syndrome. Classic WTs exhibit a triphasic histologic pattern composed of blastema, epithelium, and stroma. Occasionally, heterologous elements may also be observed. In this study we investigated a series of four WTs that occurred within a single familial aggregate and contained focal areas of neural differentiation. The tumors were evaluated histologically for the presence of neural elements and immunohistochemically for expression of neural-related markers. Genetic linkage analysis was performed on 3 of the 4 WTs. In addition to the classic triphasic histology, the WTs contained tumor rosettes (4/4), ganglion cells (2/4), foci of ganglioneuromatous differentiation (2/4), and anaplasia (1/4). Staining for chromogranin, S-100, synaptophysin, vimentin, and neuron-specific enolase was positive in all 4 tumors within the areas of neural differentiation whereas staining for CD99 (013) and glial fibrillary acidic protein was negative. Linkage analysis studies suggest that the familial predisposition gene segregating in this family is at 19q13.4. To our knowledge, this is the first reported series of WTs with neural differentiation that occurred within a single family aggregate. Genetic linkage analysis of this family is consistent with linkage to the FWT2 WT predisposition gene at 19q13.4. We propose that these tumors may represent a unique manifestation of tumor susceptibility in this family.

Chemistry test ordering patterns after elimination of predefined multitest chemistry panels in a children's hospital.

Predefined multitest chemistry panels (PMCPs) have constituted a large proportion of laboratory tests and patient charges, even in pediatric settings, despite the absence of documented clinical utility for PMCPs and the general availability of random access analyzers that do not require predefined test combinations. We eliminated PMCPs in our tertiary children's hospital but placed no other restrictions on ordering, and observed a 32.7% reduction in the number of automated chemistry tests ordered. All 23 tests in the previous PMCPs showed a decline in utilization, >50% for 8 of the tests and 20-50% for 13 others, and this change was sustained throughout an 8-month follow-up period. The total number of orders for one or more tests increased by 8.2%, but the variety of combinations that were ordered increased by 280%. The most substantial changes included a decrease in the number of orders for combinations of >15 tests, and increases in the number of orders for single tests and combinations of 2 to 5 tests. Orders for combinations identical to all of the former PMCPs declined, with the exception of the 4-test electrolyte panel. There was a marked decline in orders for a 7-test panel identical to the recently defined HCFA-AMA Basic Metabolic Panel, and orders for combinations identical to the HCFA-AMA Liver Function and Extended Metabolic panels were vanishingly rare and nonexistent, respectively. The calculated reduction in patient charges was much greater than actual cost savings, but the reduction in total tests and increase in the variety of test combinations suggest that significant savings can be realized if clinicians are encouraged to order only the tests or combinations they need without imposing procedural, financial, and regulatory burdens.

Characterization of the baboon responses to Shiga-like toxin: descriptive study of a new primate model of toxic responses to Stx-1.

The baboon response to intravenous infusion of Shiga toxin 1 (Stx-1) varied from acute renal failure, proteinuria, hyperkalemia, and melena with minimal perturbation of host inflammatory and hemostatic systems (high-dose group, 2.0 microg/kg; n = 5) to renal failure with hematuria, proteinuria, thrombocytopenia, schistocytosis, anemia, and melena (low-dose group, 0.05 to 0.2 microg/kg; n = 8). Both groups exhibited renal shutdown and died in 57 hours or less. Both groups produced urine that was positive for tumor necrosis factor and interleukin-6 although neither of these cytokines was detectable (

Successful therapy in a child with a congenital peripheral medulloepithelioma and disruption of hindquarter development.

PURPOSE: Medulloepithelioma is an embryonal multipotential neuroepithelial tumor with a striking potential for divergent differentiation. It is usually intraocular or intracerebral and associated with a good prognosis only if completely surgically excised. Data regarding therapy in children with incompletely resected tumors are limited. PATIENT AND METHODS: A girl was born with a large, peripheral, congenital medulloepithelioma associated with complete absence of the left hindquarter and anus. Plain film, ultrasonography, and magnetic resonance imaging demonstrated complete absence of the left kidney and hemipelvis. A subtotal resection of the mass and reconstruction of the tumor-related anatomical defects were performed. RESULTS: Pathologic examination showed neuroglia and pseudostratified neuroectoderm diagnostic of medulloepithelioma. She was treated with multiagent chemotherapy including vincristine, cisplatin, cyclophosphamide, carboplatin, and etoposide. She is now 50 months of age and developing normally without recurrent disease. CONCLUSIONS: A child with an incompletely resected congenital peripheral medulloepithelioma who has experienced long-term disease-free survival after treatment with chemotherapy is described. This report supports a role for adjuvant chemotherapy in the treatment of children with peripheral medulloepithelioma.

Adrenal fusion.

Fusion of the adrenal glands is a rare congenital anomaly. The six cases described here were encountered in 3537 pediatric-perinatal autopsy cases. A fused adrenal was always associated with multiple congenital anomalies, including major central nervous system malformations in four cases, renal agenesis in three cases, anomalies of internal genitalia in three cases, and complex cardiac anomalies in two cases. The fused adrenal had either a horseshoe or butterfly shape. Neither adrenal hypoplasia nor hyperplasia appeared to be present, and the histologic appearance of the fused adrenal was normal in all cases.

ETV6-NTRK3 gene fusions and trisomy 11 establish a histogenetic link between mesoblastic nephroma and congenital fibrosarcoma.

Congenital mesoblastic nephroma (CMN) is an infantile spindle cell tumor of the kidney that is subdivided into "classical" and "cellular" forms based on the degree of cellularity and mitotic activity. The histogenesis of CMN remains obscure, but relationships to other pediatric renal neoplasms have been proposed. However, cellular CMN is virtually identical histologically to congenital fibrosarcoma (CFS), a malignant tumor of fibroblasts in children of the same age group. Moreover, cytogenetic studies have reported common trisomies in CFS and cellular CMN, particularly of chromosome 11. We show here that t(12;15)(p13;q25)-associated ETV6-NTRK3 gene fusions described in CFS are also present in cellular CMN. ETV6-NTRK3 chimeric transcripts were detected in 8 of 9 cellular CMNs and 2 of 2 mixed CMNs. In contrast, all of the four classical CMNs tested were negative, as were cases of Wilms' tumor and clear cell sarcoma of the kidney. Moreover, we found trisomy 11 only in cellular or mixed CMNs with the ETV6-NTRK3 gene fusion. Our studies indicate that classical and cellular CMN have different genetic features and support the concept that cellular CMN is histogenetically related to CFS. They also provide insight into potential mechanisms involved in the transformation of the classical into the cellular form of CMN.

Pulmonary vascular resistance of children treated with nitrogen during early infancy.

BACKGROUND: We have empirically used supplemental nitrogen in newborns with a functional single ventricle and ductal-dependent systemic perfusion to prevent pulmonary vasodilation and deliver a greater proportion of flow to the systemic circulation. Thus, we reviewed patient outcome to determine whether adverse pulmonary vascular effects may be associated with this therapy. METHODS: From December 1991 to December 1995, the fraction of inspired oxygen was adjusted, with supplemental nitrogen if necessary, to maintain an oxygen saturation near 75% in 20 newborns awaiting heart transplantation. Medical records were reviewed to evaluate (1) the duration of nitrogen therapy, (2) pulmonary vascular histology, (3) postoperative pulmonary hemodynamics, and (4) survival. RESULTS: Thirteen patients underwent heart transplantation, 4 patients died without surgical intervention, and 3 patients underwent late aortic reconstruction. Supplemental nitrogen was used without exceeding a fraction of inspired oxygen of 0.21 for 38 +/- 6 days. One patient had evidence of changes of potentially irreversible pulmonary vascular disease. Pulmonary vascular resistance was not increased long-term in surviving patients. CONCLUSIONS: Supplemental nitrogen can be used to maintain a systemic oxygen saturation near 75% for an extended period in newborns with ductal-dependent systemic perfusion with no long-term adverse effect on pulmonary vascular resistance.

Spindle cell sarcoma of the kidney with ganglionic elements (malignant ectomesenchymoma) associated with chromosomal abnormalities and a review of the literature.

PURPOSE: Malignant ectomesenchymomas are tumors that exhibit both mesenchymal and neuroectodermal elements (1). We report a case thought to represent a malignant ectomesenchymoma arising in the kidney with cytogenetic abnormalities that may provide insight into the biologic basis for this unusual tumor. METHODS: We discuss the clinical features, histopathologic findings, cytogenetics, treatment, and outcome of a child with a malignant ectomesenchymoma arising in the kidney. RESULTS: An asymptomatic 16-month-old boy had a large abdominal mass. The resected tumor contained sheets of spindled cells that expressed mesenchymal markers and cartilaginous differentiation, interspersed with clusters of ganglion cells that expressed neural markers. No blastemal or epithelial elements were demonstrated. Cytogenetic analysis of the tumor revealed a hyperdiploid count with multiple numerical and structural abnormalities, including a translocation between chromosomes 12 and 15. In addition to the surgical resection, the patient was successfully treated with adjuvant chemotherapy and local radiation therapy. CONCLUSION: This is the first report of which we are aware of an ectomesenchymoma arising within the kidney. A subset of malignant ectomesenchymomas may be related to the Ewing's family of tumors (EFTs) (2), but this case did not exhibit cytogenetic features consistent with EFT. Thus, the malignant ectomesenchymoma phenotype probably represents a heterogeneous group of tumors with different genotypes and origins. Cytogenetic analysis may be instrumental in determining the appropriate therapeutic approach when faced with such a neoplasm. The outcomes of 12 other children with ectomesenchymoma are reviewed.

Xq28-linked noncompaction of the left ventricular myocardium: prenatal diagnosis and pathologic analysis of affected individuals.

Isolated noncompaction of the left ventricular myocardium (INVM) is characterized by the presence of numerous prominent trabeculations and deep intertrabecular recesses within the left ventricle, sometimes also affecting the right ventricle and interventricular septum. Familial occurrence of this disorder was described previously. We present a family in which 6 affected individuals demonstrated X-linked recessive inheritance of this trait. Affected relatives presented postnatally with left ventricular failure and arrhythmias, associated with the pathognomonic echocardiographic findings of INVM. The usual findings of Barth syndrome (neutropenia, growth retardation, elevated urinary organic acids, low carnitine levels, and mitochondrial abnormalities) were either absent or found inconsistently. Fetal echocardiograms obtained between 24-30 weeks of gestation in 3 of the affected males showed a dilated left ventricle in one heart, but were not otherwise diagnostic of INVM in any of the cases. Four of the affected individuals died during infancy, one is in cardiac failure at age 8 months, and one is alive following cardiac transplant at age 9 months. The hearts from infants who died or underwent transplantation appeared, on gross examination, to be enlarged, with coarse, deep ventricular trabeculations and prominent endocardial fibroelastosis. Histologically, there were loosely organized fascicles of myocytes in subepicardial and midmyocardial zones of both ventricles, and the myocytes showed thin, often angulated fibers with prominent central clearing and reduced numbers of filaments. Markedly elongated mitochondria were present in some ventricular myocytes from one specimen, but this finding was not reproducible. Genetic linkage analysis has localized INVM to the Xq28 region, where other myopathies with cardiac involvement have been located.

Neonatal, lethal noncompaction of the left ventricular myocardium is allelic with Barth syndrome.

Loss-of-function mutations in the G4.5 gene have been shown to cause Barth syndrome (BTHS), an X-linked disorder characterized by cardiac and skeletal myopathy, short stature, and neutropenia. We recently reported a family with a severe X-linked cardiomyopathy described as isolated noncompaction of the left ventricular myocardium (INVM). Other findings associated with BTHS (skeletal myopathy, neutropenia, growth retardation, elevated urinary organic acids, and mitochondrial abnormalities) were either absent or inconsistent. A linkage study of the X chromosome localized INVM to the Xq28 region near the BTHS locus, suggesting that these disorders are allelic. We screened the G4.5 gene for mutations in this family with SSCP and direct sequencing and found a novel glycine-to-arginine substitution at position 197. This position is conserved in a homologous Caenorhabditis elegans protein. We conclude that INVM is a severe allelic variant of BTHS with a specific effect on the heart. This finding provides further structure-function information about the G4.5 gene product and has implications for unexplained cases of severe infantile hypertrophic cardiomyopathy in males.

Acute renal failure in idiopathic nephrotic syndrome.

Acute renal failure (ARF) associated with idiopathic nephrotic syndrome has been reported in adults with advanced age but is a rare event in children. We have reviewed the literature on this subject and report an additional pediatric case. The pathogenetic mechanisms which may lead to ARF during the course of idiopathic nephrotic syndrome are reviewed with a brief discussion of the role of angiotensin II and angiotensin converting enzyme inhibition in this setting. Although no consensus has emerged for the prevention and treatment of ARF in patients with nephrotic syndrome, a combination of salt-poor albumin and diuretics to reduce interstitial edema may be beneficial as a preventive measure. Once acute tubular necrosis is diagnosed, dialysis may be indicated. In the majority of reports the prognosis for recovery of renal function has been good even in patients in whom long-term dialysis was required.

Aprosencephaly and cerebellar dysgenesis in sibs.

Aprosencephaly is a rare, lethal malformation sequence of the central nervous system that has been attributed to a postneuralation encephaloclastic process. We describe autopsy findings consistent with aprosencephaly in 2 fetuses conceived from a consanguineous mating (first cousins). Both showed anencephalic manifestations; however, the crania were intact, with fused sutures. The neuropathologic findings were essentially identical. Each fetus had complete absence of the telecephalon and pyramidal tracts, rudimentary diencephalic and mesencephalic structures, primitive cerebellar hemispheres, posterolateral clusters of primitive neural cells in the medullas suggesting an abnormality of neural migration, a normally-formed spinal cord, and retinal dysplasia within normally-formed globes. In addition, both fetuses manifested a peculiar perivascular mesenchymal proliferation seen only within the central nervous system. The similarity of these cases, coupled with parental consanguinity, suggests a primary malformation in brain development due to the homozygous representation of a mutant allele. We hypothesize that these patients may represent a defect in a gene important in brain development, the nature of which has yet to be elucidated.

Congenital chest wall mesenchymal hamartoma.

The case of an infant with mesenchymal hamartoma of the chest wall is presented, and the role of conservative diagnostic and therapeutic intervention is emphasized. A large mass that involved the right hemithorax and chest wall was detected in utero on routine ultrasonographic studies and diagnosed as mesenchymal hamartoma by percutaneous fine needle biopsy at 4 days after birth. The mass did not enlarge after birth, but surgical debulking was necessary at 1 month because of progressive respiratory compromise. Tumor regrowth was noted over the ensuing 8 months, and a second debulking at 9 months has been followed by a 6-year interval without evidence of recurrence.

Atelencephalic aprosencephaly.

Absence of the telencephalon and diencephalon characterizes the syndrome of aprosencephaly, while in atelencephaly, only the telencephalon is absent. Atelencephalic aprosencephaly is characterized by the presence of at least a rudimentary diencephalon. Embryologically, aprosencephaly is thought to occur after the optic vesicles form but before the cerebral vesicles appear. The syndrome is quite rare, with only 10 cases previously reported. We describe two fetuses with atelencephalic aprosencephaly. A 25-week estimated gestational age fetus was born to first-cousin parents and had a prenatal ultrasonographic diagnosis of anencephaly. The second, a 19-week estimated gestational age fetus, was thought to have semilobar holoprosencephaly by prenatal ultrasound. At autopsy, neuropathologic examination in both cases showed virtual absence of the cerebral hemispheres with an incomplete diencephalon. Microscopic examination in one case revealed disorganized neuropil with a proliferative vasculopathy. The optic globes were completely formed and attached to hypoplastic optic nerves, but retinal dysplasia was apparent histologically in both cases, and bilateral colobomata were present in one case. The findings in these cases demonstrate a spectrum of congenital variations that lie between the syndromes of atelencephaly and aprosencephaly, underscoring the complexity of the congenital anomalies.