Mamdouha A. Barmada

Neonatal electroencephalography and neuropathology.

One-hundred-eight EEGs from 47 newborn infants were compared with the postmortem neuropathological findings. The degree of EEG background abnormality had good correlation with the severity of the brain lesion; the more severe the EEG background abnormality, the more extensive and intensive the morphological change. Widespread encephalomalacia was demonstrated in six infants who manifested isoelectric tracings. In particular, cerebral cortex, corpus striatum, thalamus, midbrain, and pons were affected in all patients with this abnormal EEG pattern. Burst-suppression patterns, which were seen in seven infants, also correlated with multifocal severe brain damage, but there was no common structure that was consistently affected for all patients with this pattern. Positive rolandic sharp-wave transients (PRS) appeared highly specific for white matter lesions. All eight infants with PRS had white matter lesions. However, the sensitivity of PRS for white matter lesions was not high (32%), and the white matter lesions of PRS-positive patients were not necessarily composed of periventricular leuko-malacia. The sensitivity of EEG asymmetry was also low (40%) for the focality of morphological change, although the specificity was relatively high (85%). The origin of seizure discharges, on the other hand, had poor correlation with the site of the brain lesion.

Recombinant vesicular stomatitis virus targeted to Her2/neu combined with anti-CTLA4 antibody eliminates implanted mammary tumors

Vesicular stomatitis virus (VSV) is being developed for cancer therapy. We created a recombinant replicating VSV (rrVSV) that preferentially infected Her2/neu expressing breast cancer cells. We now used this rrVSV to treat macroscopic peritoneal tumor implants of a mouse mammary tumor cell line stably transfected to express Her2/neu. rrVSV therapy alone prolonged survival but did not cure any animals. rrVSV therapy combined with antibody to TGFb or antibody to IL-10 receptor (IL-10R) each produced cure in one of six animals. Strikingly, rrVSV therapy combined with anti-CTLA4 monoclonal antibody (MAb) produced cure in four of five animals. Anti-CTLA4 MAb was only effective when administered within one day of rrVSV therapy. Cure required CD4 T-cells early (<7 days) and late (>7 days) after rrVSV therapy whereas CD8 T-cells were required only late (>7 days) after rrVSV therapy. Surviving animals were resistant to re-challenge with D2F2/E2 suggesting a memory immune response. Histopathologic analysis demonstrated a dense inflammatory infiltrate of tumor nodules within days of therapy and foamy histiocytes replacing the tumor nodules 2 weeks following therapy. These studies demonstrate that targeted rrVSV combined with anti-CTLA4 MAb can eliminate established macroscopic tumor implants by eliciting an anti-tumor CD4 and CD8 T-cell immunologic response.

Comparison of in vitro antibody-targeted cytotoxicity using mouse, rat and human effectors

Abstract Antibodies can direct tumor cell lysis by activating complement-mediated and cell-mediated cytoxicities (antibody-dependent cell-mediated cytotoxicity, ADCC). Clinical translation of these effects into successful cancer therapy has been slow. Choosing an appropriate animal model to test new therapeutic strategies is difficult because of species differences in immunological effector functions. In previous work, we found that an unmodified anti-ganglioside mouse IgG3 monoclonal antibody (mAb), 3F8, could successfully treat clinical tumors in humans and experimental tumors in rats but not experimental tumors in mice. We explored the reasons for this species difference by performing in vitro antibody-dependent cytotoxicity assays comparing the potency of polymorphonuclear neutrophils (PMN), natural killer (NK) cells and complement from the three species: mouse, rat and human. 3F8-dependent complement-mediated cytotoxicity produced more than 70% specific release when human and rat sera were used and only 20% with mouse serum. PMN-mediated ADCC was 35%–70% with human effectors, 25%–60% with rat and undetectable with mouse. Human eosinophils did not contribute to this ADCC. Cytotoxicity utilizing interleukin-2-activated NK cells was antibody-independent in all three species but the specific release was 60%–70% with human and rat NK cells and 10% with mouse NK cells. These data suggest that, for mouse IgG3, the rat may provide a more relevant rodent model than the mouse for testing the in vivo antitumor effects of monoclonal antibodies.

Timing of brain insults in severe neonatal encephalopathies with isoelectric EEG

In a neonatal intensive care unit of a large obstetric hospital, 20 neonates (7 preterm, 9 term, 4 postterm) with at least one isoelectric recording were treated over a 6-year period. Seventy-four EEGs were obtained in this cohort, including 36 isoelectric recordings. Seven infants in this group had evidence of a predominant antepartum component of a pathologic process based on placental, postmortem examination findings, or clinical history. Of the 16 placentas available for review, chronic lesions were observed in 13 of 16 specimens, including villitis, infarction, dysmaturity, and thrombosis. Seven of 9 patients with postmortem neuropathologic examinations had evidence of chronic lesions, principally neuronal necrosis, infarction, and microcalcifications. An additional 10 infants had evidence of an antepartum contribution to a pathologic process that continued into either the intrapartum or neonatal periods, based on maternal and/or neonatal medical factors. Clinical findings supportive of antepartum insults included intrauterine growth retardation, antepartum hemorrhage, abnormal antepartum fetal heart rate patterns, and maternal medical complications. Three patients had either intrapartum- or neonatal-onset of injury. Clinical signs of severe encephalopathy, however, were present in the immediate postnatal period in most patients (18 of 20; 90%). Assessment of clinical and pathologic information on neonates with isoelectric EEGs may estimate the timing of brain injury to the antepartum period, as opposed to, or in addition to, the labor and delivery periods. A neonate who suffered brain injury before parturition may be neurologically depressed after birth with absence of electrocerebral activity on EEG.

Malignancy after retinoblastoma: Secondary cancer or recurrence?

The risk of second malignancy after retinoblastoma is reported to be as high as 20% at 10 years after initial diagnosis. This incidence may be an overestimate because of difficulties in distinguishing a second malignancy from recurrent tumor. We encountered a patient with bilateral retinoblastoma who developed a temporal mass 3.5 years after initial treatment for what had first been diagnosed as rhabdomyosarcoma; further study suggested that it was recurrent retinoblastoma manifesting as primitive neuroectodermal tumor (PNET) with multilineage differentiation. Chromosome 13 abnormalities were compatible with either rhabdomyosarcoma or recurrent retinoblastoma. To determine how often second malignancies in retinoblastoma patients may be confused with recurrent primary tumor, we reviewed our experience at Childrens Hospital of Pittsburgh. Of 43 retinoblastoma patients seen between 1951 and 1992, presumed second malignancies were documented in four, including the current case. Of the three other second tumors, one had both neural and skeletal muscle differentiation; another was diagnosed as rhabdomyosarcoma unclassifiable as embryonal or alveolar; the last was an osteosarcoma. Only the osteosarcoma was clearly a second neoplasm; two and perhaps three of the other cases may be recurrent retinoblastoma. The distinction between second malignancy and recurrent retinoblastoma may be difficult but is worth determining, because treatment may differ, depending on the correct designation.

Pancytopenia and vacuolation of marrow precursors associated with necrotizing encephalopathy

Subacute necrotizing encephalopathy (SNE) or Leigh disease is an autosomal recessive disorder associated with various defects of oxidative phosphorylation. Two reports have described the concurrence of SNE with pancytopenia and vacuolation of bone marrow precursors, and have raised the possibility that this symptom complex may be part of a spectrum of diseases which includes Pearsons syndrome (vacuolation of bone marrow precursors, sideroblastic anaemia, exocrine pancreatic dysfunction). We describe a case of Pearsons syndrome in which haematological manifestations antedated progressive neurological deterioration by several years. Cytogenetic studies showed an inverted duplication of chromosome 9 (qh) [inv dup (9) (qh)]. We suggest that cytopenia associated with vacuolation of bone marrow precursors even without clinically apparent central nervous system pathology should prompt consideration of SNE, or related diseases. Conversely, a diagnosis of SNE should prompt evaluation of other organ system functions including bone marrow. Cytogenetic evaluation of other patients with SNE may determine whether the 9 (qh) findings are pathogenetic.

Congenital alopecia, seizures, and psychomotor retardation in three siblings

Three siblings, devoid of hair at birth, had an unusual autosomal recessive disorder characterized by universal congenital alopecia, microcephaly, seizures, psychomotor retardation, and severe growth failure. Metabolic and chromosome studies were normal. Skin biopsies disclosed immature hair follicles, some of which were filled with keratotic material but had no hair shafts. Neuropathologic features included cerebral cortical hypoplasia, neuronal depletion, and microcalcifications. The familial occurrence of universal congenital alopecia conjoined with nonprogressive central nervous system abnormalities in this and other kindreds defines a nosologic group of neurocutaneous disorders in which congenital alopecia is the solitary cutaneous manifestation.

Viral infection of implanted meningeal tumors induces antitumor memory T-cells to travel to the brain and eliminate established tumors.

BACKGROUND Leptomeningeal metastases occur in 2%-5% of patients with breast cancer and have an exceptionally poor prognosis. The blood-brain and blood-meningeal barriers severely inhibit successful chemotherapy. We have developed a straightforward method to induce antitumor memory T-cells using a Her2/neu targeted vesicular stomatitis virus. We sought to determine whether viral infection of meningeal tumor could attract antitumor memory T-cells to eradicate the tumors. METHODS Meningeal implants in mice were studied using treatment trials and analyses of immune cells in the tumors. RESULTS This paper demonstrates that there is a blood-meningeal barrier to bringing therapeutic memory T-cells to meningeal tumors. The barrier can be overcome by viral infection of the tumor. Viral infection of the meningeal tumors followed by memory T-cell transfer resulted in 89% cure of meningeal tumor in 2 different mouse strains. Viral infection produced increased infiltration and proliferation of transferred memory T-cells in the meningeal tumors. Following viral infection, the leukocyte infiltration in meninges and tumor shifted from predominantly macrophages to predominantly T-cells. Finally, this paper shows that successful viral therapy of peritoneal tumors generates memory CD8 T-cells that prevent establishment of tumor in the meninges of these same animals. CONCLUSIONS These results support the hypothesis that a virally based immunization strategy can be used to both prevent and treat meningeal metastases. The meningeal barriers to cancer therapy may be much more permeable to treatment based on cells than treatment based on drugs or molecules.