Treatment of Monomorphic Posttransplant Lymphoproliferative Disorder in Pediatric Solid Organ Transplant: A Multicenter Review

Posttransplant lymphoproliferative disorder (PTLD) is the most common posttransplant malignancy in children. We reviewed data from 3 Canadian pediatric centers to determine patient characteristics, treatment approaches, and outcomes for children with monomorphic PTLD. There were 55 eligible children diagnosed between January 2001 to December 2021. Forty-eight patients (87.2%) had B-cell PTLD: Burkitt lymphoma (n = 25; 45.4%) and diffuse large B-cell lymphoma (n = 23; 41.2%), the remainder had natural killer (NK)/T-cell lymphoma (n = 5; 9.1%), Hodgkin lymphoma (n = 1;1.8%), or other (n = 1;1.8%). Thirty-nine (82.1%) patients with B-cell PTLD were treated with rituximab and chemotherapy with or without a reduction in immunosuppression (reduced immune suppression). The chemotherapy used was primarily one of 2 regimens: Mature Lymphoma B-96 protocol in 22 patients (56.4%) and low-dose cyclophosphamide with prednisone in 14 patients (35%). Most patients with T/NK-cell lymphoma were treated with reduced immune suppression + chemotherapy (n = 4; 80%). For all patients with monomorphic PTLD, the projected 3-year event-free survival/3-year overall survival was 62% and 77%, respectively. Of the patients, 100% with T/NK-cell PTLD 100% progressed or relapsed and, subsequently, died of disease. For patients with B-cell PTLD, there was no significant difference in outcome between the two main chemotherapy regimens employed.

Child health nursing in the Solomon Islands: A qualitative evaluation of the impact of the 'Bachelor of nursing - Child health'

AIM

To explore graduates' perceptions of the impact on nursing practice of a new postgraduate course in child health, developed and implemented in the Solomon Islands in 2016.

BACKGROUND

The Bachelor of Nursing - Child Health was implemented in 2016 to develop nurses' knowledge and skills in child health and paediatric care with the intent to improve national child health outcomes.

DESIGN

A qualitative exploratory, descriptive design was used to evaluate the impact of the Bachelor of Nursing - Child Health on graduates' nursing practice.

METHODS

Fourteen nurses who graduated from the first cohort of students enrolled in the child health course were purposively selected to participate. Participants engaged in individual semi-structured interviews, conducted between August and December 2018. A thematic analysis was undertaken following Braun and Clarke's six-phase process.

RESULTS

Findings from the study demonstrate positive impacts of the course on graduates' nursing practice. These include a perceived enhanced quality of care through their commitment to evidence-based practice, the ability to contribute to capacity building of colleagues, the reinforcement of provincial public health programmes and expanded participation in managerial activities. Following graduation, most alumni took on senior roles and greater responsibilities, felt more confident in managing unwell children, felt there was better access to and quality of child health care at the community and broader country levels and felt recognised by colleagues and communities. Some graduates faced resistance from colleagues to change practice and felt that despite being given greater responsibilities, nursing levels and salaries remained unchanged. This reflected a potential lack of recognition from hospital or provincial managers, the Nursing Council as the regulatory body for the nursing profession, and the Ministry of Health and Medical Services. A lack of human and material resources also impacted quality of care.

IMPLICATIONS FOR NURSING AND HEALTH POLICY

Findings from this study underline the need for the Solomon Islands National University, the Nursing Council, the Public Service and the Ministry of Health and Medical Services to concord and delineate formal accreditation standards for child health nurses. Overall, collaborative efforts and commitments at local, regional and global levels are required to support child health nurses in their ability and ambition to improve national child health outcomes.

CONCLUSIONS

Findings from this study demonstrate positive impacts of the course on graduates' nursing practice. The impact of increasing nurses' knowledge and skills on national child health outcomes could be significant. Ongoing implementation and recognition of this course in the Solomon Islands, as well as more broadly across the Pacific region, are recommended.

Treatment outcomes of childhood PICALM::MLLT10 acute leukaemias

The prognostic impact of PICALM::MLLT10 status in childhood leukaemia is not well described. Ten International Berlin Frankfurt Münster-affiliated study groups and the Children's Oncology Group collaborated in this multicentre retrospective study. The presence of the PICALM::MLLT10 fusion gene was confirmed by fluorescence in situ hybridization and/or RNA sequencing at participating sites. Ninety-eight children met the study criteria. T-cell acute lymphoblastic leukaemia (T-ALL) and acute myeloid leukaemia (AML) predominated 55 (56%) and 39 (40%) patients, respectively. Most patients received a chemotherapy regimen per their disease phenotype: 58% received an ALL regimen, 40% an AML regimen and 1% a hybrid regimen. Outcomes for children with PICALM::MLLT10 ALL were reasonable: 5-year event-free survival (EFS) 67% and 5-year overall survival (OS) 76%, but children with PICALM::MLLT10 AML had poor outcomes: 5-year EFS 22% and 5-year OS 26%. Haematopoietic stem cell transplant (HSCT) did not result in a significant improvement in outcomes for PICALM::MLLT10 AML: 5-year EFS 20% for those who received HSCT versus 23% for those who did not (p = 0.6) and 5-year OS 37% versus 36% (p = 0.7). In summary, this study confirms that PICALM::MLLT10 AML is associated with a dismal prognosis and patients cannot be salvaged with HSCT; exploration of novel therapeutic options is warranted.

Outcomes of Coronavirus Disease 2019 Infection in Children and Adolescents With Cancer in Canada: Population-based Study and Systematic Review

Published outcomes for children with cancer with coronavirus disease 2019 (COVID-19) have varied. Outcome data for pediatric oncology patients in Canada, outside of Quebec, have not been reported. This retrospective study captured patient, disease, and COVID-19-related infectious episode characteristics and outcome data for children, 0 to 18 years, diagnosed with a first COVID-19 infection between January 2020 to December 2021 at 12 Canadian pediatric oncology centers. A systematic review of pediatric oncology COVID-19 cases in high-income countries was also undertaken. Eighty-six children were eligible for study inclusion. Thirty-six (41.9%) were hospitalized within 4 weeks of COVID-19; only 10 (11.6%) had hospitalization attributed to the virus, with 8 being for febrile neutropenia. Two patients required intensive care unit admission within 30 days of COVID-19 infection, neither for COVID-19 management. There were no deaths attributed to the virus. Of those scheduled to receive cancer-directed therapy, within 2 weeks of COVID-19, 20 (29.4%) experienced treatment delays. Sixteen studies were included in the systematic review with highly variable outcomes identified. Our findings compared favorably with other high-income country's pediatric oncology studies. No serious outcomes, intensive care unit admissions, or deaths, in our cohort, were directly attributable to COVID-19. These findings support the minimization of chemotherapy interruption after COVID-19 infection.

A Human Ex Vivo Skin Model to Study Candida auris Biofilms

Candida auris can persist for long periods on hospital surfaces and on the skin. C. auris has the ability to form drug-resistant biofilms, which can substantially impact on patient outcome. In comparison to Candida albicans, C. auris has a lower capacity to form biofilms in in vitro models and a higher capacity when tested on animal skin models. Intraspecies variation is shown to exist, with some clinical isolates having greater biofilm capabilities than others. There is a need for models that closely mimic the real niches where infection occurs on human patients. This protocol describes, in detail, a human skin model to study C. auris biofilm formation using catheterized and non-catheterized skin.

Safety of administration of BNT162b2 mRNA (Pfizer-BioNTech) COVID-19 vaccine in youths and young adults with a history of acute lymphoblastic leukemia and allergy to PEG-asparaginase

Vaccinationis a critical tool in the prevention of COVID-19 infection for individuals and for communities. The mRNA vaccines contain polyethylene glycol (PEG) as a stabilizer. Currently, in North America, only the BNT162b2 (Pfizer-BioNTech) mRNA vaccine is approved for individuals aged 12-17. Most patients treated with contemporary regimens for acute lymphoblastic leukemia receive PEG-asparaginase (PEG-ASNase) and 10%-30% will develop allergic reactions. Optimizing access and safety for vaccine administration for these patients is critical. This report describes a process developed to support COVID vaccination in a cohort of adolescents and young adults with a history of PEG-ASNase allergy.

Detecting long-range interactions between migrating cells

Chemotaxis enables cells to systematically approach distant targets that emit a diffusible guiding substance. However, the visual observation of an encounter between a cell and a target does not necessarily indicate the presence of a chemotactic approach mechanism, as even a blindly migrating cell can come across a target by chance. To distinguish between the chemotactic approach and blind migration, we present an objective method that is based on the analysis of time-lapse recorded cell migration trajectories: For each movement step of a cell relative to the position of a potential target, we compute a p value that quantifies the likelihood of the movement direction under the null-hypothesis of blind migration. The resulting distribution of p values, pooled over all recorded cell trajectories, is then compared to an ensemble of reference distributions in which the positions of targets are randomized. First, we validate our method with simulated data, demonstrating that it reliably detects the presence or absence of remote cell-cell interactions. In a second step, we apply the method to data from three-dimensional collagen gels, interspersed with highly migratory natural killer (NK) cells that were derived from two different human donors. We find for one of the donors an attractive interaction between the NK cells, pointing to a cooperative behavior of these immune cells. When adding nearly stationary K562 tumor cells to the system, we find a repulsive interaction between K562 and NK cells for one of the donors. By contrast, we find attractive interactions between NK cells and an IL-15-secreting variant of K562 tumor cells. We therefore speculate that NK cells find wild-type tumor cells only by chance, but are programmed to leave a target quickly after a close encounter. We provide a freely available Python implementation of our p value method that can serve as a general tool for detecting long-range interactions in collective systems of self-driven agents.

Fifteen-minute consultation: Assessment, surveillance and management of hemihypertrophy

This article aims to provide a structured and concise guide for the general paediatrician managing a child with hemihypertrophy. Hemihypertrophy is a relatively uncommon condition. The significance is that a proportion of those affected are at risk of developing malignancies in childhood. For these children regular surveillance is required. We have outlined how one might assess and investigate a child presenting with hemihypertrophy. We have also formulated a practicable surveillance strategy which is in line with the current Royal College of Paediatrics and Child Health (RCPCH) guideline 'Wilms' tumour surveillance in at-risk children'.

Polymer Chain Conformation and Dynamical Confinement in a Model One-Component Nanocomposite

We report a neutron-scattering investigation on the structure and dynamics of a single-component nanocomposite based on SiO_{2} particles that were grafted with polyisoprene chains at the entanglement limit. By skillful labeling, we access both the monomer density in the corona as well as the conformation of the grafted chains. While the corona profile follows a r^{-1} power law, the conformation of a grafted chain is identical to that of a chain in a reference melt, implying a high mutual penetration of the coronas from different particles. The brush crowding leads to topological confinement of the chain dynamics: (i) At local scales, the segmental dynamics is unchanged compared to the reference melt, while (ii) at the scale of the chain, the dynamics appears to be slowed down; (iii) by performing a mode analysis in terms of end-fixed Rouse chains, the slower dynamics is tracked to topological confinement within the cone spanned by the adjacent grafts; (iv) by adding 50% matrix chains, the topological confinement sensed by the grafted chain is lifted partially and the apparent chain motion is accelerated. We observe a crossover from pure Rouse motion at short times to topological confined motion beyond the time when the segmental mean squared displacement has reached the distance to the next graft.

The world's first immunization campaign: the Spanish Smallpox Vaccine Expedition, 1803-1813

Smallpox produced the death of up to thirty percent of those infected, so Jenner's preventive method spread quickly. The Spanish government designed and supported a ten-year effort to carry smallpox vaccine to its American and Asian territories in a chain of arm-to-arm vaccination of children. An expedition directed by Doctor Francisco Xavier de Balmis sailed from Corunna in November 1803, stopping in the Canary Islands, Puerto Rico, and Venezuela. Balmis led a subexpedition to Cuba, Mexico, and the Philippines; his assistants returned to Mexico in 1807, while Balmis took vaccine to China and returned to Spain (and again to Mexico, 1810-13). Vice-director José Salvany and his staff took vaccine to present-day Colombia, Ecuador, Peru, Bolivia, and Chilean Patagonia. The Spanish Royal Philanthropic Vaccine Expedition shows the first attempts to solve questions still important for the introduction of new immunizations--professionalization in public health, technology transfer, protection of research subjects, and evaluation of vaccine efficacy, safety, and cost.

Large variations in the ovalbumin content in six European influenza vaccines

Since influenza vaccines are propagated in embryonated chicken eggs, they contain residual egg proteins (mostly ovalbumin). This could lead to the induction of allergic reactions in vaccinated individuals that are allergic to egg. The ovalbumin content in six influenza vaccines, available on the Swedish market in the autumn of 2004, was studied using a commercial ELISA kit. The results show a high degree of variation in ovalbumin content between the different influenza vaccines, ranging between 28 ng/ml and 1.1 microg/ml. No vaccine, however, had an ovalbumin concentration above the limit of 1.0 microg per dose (i.e. 2.0 microg/ml) set by the European Pharmacopoeia for the actual types of influenza vaccines. Thus results presented here clearly show that a tightening of the limit is fully possible.

Molecular cloning and preliminary functional analysis of two novel human KRAB zinc finger proteins, HKr18 and HKr19

cDNA clones encoding two novel human KRAB zinc finger proteins, HKr18 and HKr19, were isolated from a human testis cDNA library. Their corresponding genes were later identified in sequences originating from chromosomes 19 and 7, respectively. On the basis of the collected information from gene and cDNA sequences, Hkr18 was found to be a protein of 94 kDa with 20 zinc finger motifs in its C terminus. The HKr19 is a smaller protein, with a molecular weight of 56 kDa containing 11 zinc finger motifs. Both HKr18 and HKr19 contained a KRAB A as well as a KRAB B domain in their N termini. Northern blot analysis showed expression of HKr18 in all human tissues tested, indicating a ubiquitous expression pattern. In contrast, HKr19 showed a more restricted tissue distribution, with detectable expression primarily in testis and fetal tissues. The HKr19 protein is a member of the large ZNF91 subfamily of KRAB zinc finger genes. A PCR-based analysis of the expression of HKr19 and other closely related genes showed that lymphoid, myeloid, and nonhematopoietic cells expressed different sets of these genes. This latter finding indicates that some members of the ZNF91 family may be involved in regulating lineage commitment during hematopoietic development. Transfection of various parts of HKr19 into human embryonic kidney cells (HEK 293 cells) showed that the entire protein and its zinc finger region were toxic to these cells when expressed at high levels. In contrast, the KRAB domain and the linker region seemed to be well tolerated.

Conserved interaction between distinct Kruppel-associated box domains and the transcriptional intermediary factor 1

The Krüppel-associated box (KRAB) domain, originally identified as a 75-aa sequence present in numerous Krüppel-type zinc-finger proteins, is a potent DNA-binding-dependent transcriptional repression domain that is believed to function through interaction with the transcriptional intermediary factor 1 (TIF1) beta. On the basis of sequence comparison and phylogenetic analysis, we have recently defined three distinct subfamilies of KRAB domains. In the present study, individual members of each subfamily were tested for transcriptional repression and interaction with TIF1 beta and two other closely related family members (TIF1 alpha and TIF1 gamma). All KRAB variants were shown, (i) to repress transcription when targeted to DNA through fusion to a heterologous DNA-binding domain in mammalian cells, and (ii) to interact specifically with TIF1 beta, but not with TIF1 alpha or TIF1 gamma. Taken together, these results implicate TIF1 beta as a common transcriptional corepressor for the three distinct subfamilies of KRAB zinc-finger proteins and suggest a high degree of conservation in the molecular mechanism underlying their transcriptional repression activity.

Comparative analysis of KRAB zinc finger proteins in rodents and man: evidence for several evolutionarily distinct subfamilies of KRAB zinc finger genes

Although the KRAB zinc finger proteins probably constitute the single largest class of transcription factors within the human genome, almost nothing is known about their biological function. To increase our knowledge about this interesting and relatively unexplored family of potent transcriptional repressors, we here present the cloning, structural analysis, and expression study of three novel mouse KRAB zinc finger proteins. In addition, we present an extensive comparative analysis of various members of this gene family based on the structure of the common KRAB A motif. At least three larger subfamilies of KRAB zinc finger proteins are identified: one carrying the classical KRAB A motif only, another holding both a classical KRAB A and a classical KRAB B motif, and a third holding a classical KRAB A and a highly divergent KRAB B domain, named b. A large variation both in size and in primary amino acid sequence was observed in the linker region between the KRAB domain and the C-terminally located zinc finger repeats. This variability indicates that this region is of minor importance for the biological function of KRAB-containing zinc finger proteins. The fact that in many zinc finger genes, the entire or almost the entire linker region is composed of degenerate finger motifs substantiates this conclusion. The absence of identifiable KRAB A and B motifs in the genome of yeast, Saccharomyces cerevisiae, indicates a relatively late appearance of the KRAB domain in evolution and may suggest that the biological functions are restricted to multicellular organisms. In addition, we show that the expression of individual members of one subfamily of KRAB zinc finger genes is restricted to specific hematopoietic cell lineages. This finding suggests that KRAB zinc finger proteins may play a role in lineage commitment, possibly silencing leakage transcription from nonlineage-expressed genes.

Functional epitope mapping of insulin-like growth factor I (IGF-I) by anti-IGF-I monoclonal antibodies

Based on a collection of monoclonal antibodies (mAb) against insulin-like growth factor I (IGF-I), we have defined the IGF-I epitopes involved in the interaction with IGF-binding proteins (IGFBP) and IGF-I receptors. We have also characterized the ability of these antibodies to block IGF-I-induced survival of the IL-3-dependent Ba/F3 cell line. More than 140 hybridomas secreting IGF-I-specific mAb were characterized, of which 28 were studied in detail. They display apparent affinity constants ranging from less than 10(6) to 10(10) M-1 and varying crossreactivity with IGF-II, including 2 mAb with higher affinity for IGF-II than for IGF-I. None crossreact with insulin or any other growth factor tested. Using both enzyme immunoassays and real-time biospecific interaction analysis, we have identified 8 epitopic clusters related to the primary structure of IGF-I, according to mAb reactivity to synthetic peptides, proteolytic fragments of IGF-I, and various IGF-I mutants. The mAb panel also was used to map the IGF domains implicated in the interaction with IGFBP and IGF-I receptors. An IGF-I domain has been identified that remains exposed after IGF-I binding to IGFBP-1 or to IGFBP-3, which is recognized by 6 different mAb. The mAb in this group also bind IGF-I, when complexed to the type-1 IGF receptor on the murine pro-B cell line Ba/F3, and BALB/c 3T3 fibroblasts overexpressing the human receptor. Finally, IGF-I-promoted survival can be blocked with mAb specific for target epitopes, and their potential use in tumor cell growth control is discussed.

Glucose challenge testing in pregnancy

This study examines results of routine glucose challenge screening in 608 third-trimester patients in a private practice setting. Four patient categories were defined on the basis of the results: normal, abnormal screen with normal glucose tolerance test, borderline glucose tolerance test, and gestational diabetes. When only standard prenatal management practices were used, the fetal outcomes in the four groups were not measurably different. The costs of these procedures resulted in an expenditure of $722.31 per diagnosis of gestational diabetes. This seems excessive in view of the negligible impact of these studies on fetal outcome. Our impression was that routine third-trimester dietary counseling, postprandial glucose monitoring without challenge testing, and evaluation of cases of suspected fetal macrosomia would result in comparable outcome at significantly reduced cost.

RBC lithium transport in the psychoses

In vitro and in vivo red blood cell (RBC) lithium (Li+) intracellular/extracellular ratios were determined in 93 DSM-III schizophrenics (SCZ) in 47 DSM-III schizophreniform disorder patients (SF), in 22 DSM-III bipolar manics (M), in 15 affective disorders patients with mood-incongruent psychotic features (AD-MIP), and in 40 normal controls. There were no significant differences among groups in the in vitro Li+ ratio. Similarly, there was no significant difference among patient groups in the in vivo Li+ ratio. Furthermore, there was no significant difference in the mean Li+ ratios between the Li+-responsive and nonresponsive schizophrenic-like subjects. However, the distribution of Li+ ratios (both in vitro and in vivo) in the Li+-responsive group was significantly abnormal, showing more ratios in the extremes of the distribution (a platykurtic distribution).

Complete or partial homozygosity of chromosome 13 in primary retinoblastoma

Sixteen retinoblastomas were examined with chromosome 13 polymorphic probes to determine the frequency of homozygosity for the chromosome in the tumors. Each of the tumors had two cytogenetically normal appearing No. 13 chromosomes. Nontumorous cells from the same patients were heterozygous for the various polymorphic chromosome 13 probes used. At least partial homozygosity for a single chromosome 13 was observed in 75% of the tumors. These studies confirm and extend previous studies which suggest that homozygosity or hemizygosity at RBI occurs in the majority of retinoblastomas. We also demonstrate in an additional tumor that rapid clonal evolution from hemizygosity to homozygosity can occur in the tumor.

Preinduction cervical ripening with sequential use of prostaglandin E2 gel

Two hundred patients received a prostaglandin E2-containing gel for preinduction cervical ripening. The gel was administered every 6 hours until a Bishop score greater than or equal to 7 was obtained or the attending physician deemed induction necessary. Forty-eight percent of the patients labored "spontaneously" after one or more gel applications. The average cumulative change in Bishop score with sequential application of the gel was 2.7. Sequential application of the prostaglandin gel proved no more effective in the process of preinduction cervical ripening than single application of the gel with a similar period of observation.

Membranes, methylation and lithium responsive psychoses

Data are presented showing that the erythrocyte ghost membranes of lithium-responsive and non-responsive schizophrenic-like patients are different from control membranes. In both groups of patients there was a significant decrement of phosphatidylcholine (PC) which was largely compensated for by an increase in sphingomyelin. The decrement in PC may in part be associated with a decrease in phospholipid methylation which converts phosphatidylethanolmine (PE) to PC. Interestingly, in the lithium-responsive but not the non-responsive patients, lithium stimulates methylation activity. This stimulation may affect a variety of membrane functions, e.g. adenyl cyclase activity, which would be involved in lithium's therapeutic actions.

Characteristics of phospholipid methylation in human erythrocyte ghosts: relationship(s) to the psychoses and affective disorders

Recent studies have shown that patients with a schizophrenic-like illness have a significant deficit in erythrocyte ghost membrane (EGM) phosphatidylcholine (PC); patients with the most severe deficiency showed a marked decrease in Na+-Li+ counterflow activity (Hitzemann et al. 1984a and b). The present study was undertaken to see if the decrement in PC is associated with a decrease in phospholipid methylation activity. Phospholipid methylation in human EGMs is distinctly different from that in rat EGMs (Hirata and Axelrod 1980) in that the human activity is not Mg++-dependent, and apparent methyltransferase I activity is located in the external membrane surface. The patient population consisted of 20 DSM-III schizophrenics (SCZ), 13 DSM-III schizophreniform (SF) disorder patients, and 11 DSM-III manics (M). Twelve age- and sex-matched controls were used for the comparison group. Methylation activity was significantly decreased in all three patient groups, although the M group had significantly higher activity than the SF group. Twenty-four of the SCZ and SF patients entered a Li+ trial. The Li+ responder group (n = 8) showed significantly lower activity than the nonresponder group (n = 16). Overall, we conclude that the decrement in phospholipid methylation activity partially contributes to the decrement in PC levels.

Tumorigenicity of human HT1080 fibrosarcoma X normal fibroblast hybrids: chromosome dosage dependency

The tumorigenic capacity of hybrids formed by fusion of the highly tumorigenic HT1080 human fibrosarcoma cell line with nontumorigenic normal fibroblasts was examined. The HT1080 also contains an activated N-ras oncogene. Near-tetraploid hybrids which contained an approximately complete chromosomal complement from both parental cells were nontumorigenic when 1 X 10(7) cells were injected s.c. into athymic (nude) mice, whereas the parental HT1080 cells produced tumors in 100% of the animals with no latency period following injection of 2 X 10(6) cells. Tumorigenic variants were obtained from these hybrids which had lost only a few chromosomes compared to cells from the nontumorigenic mass cultures. In addition, several near-hexaploid hybrids were obtained which contained approximately a double chromosomal complement from the HT1080 parental line and a single chromosomal complement from the normal fibroblasts. All of these near-hexaploid hybrids produce tumors in 100% of nude mice with no latency period. Our results indicate that tumorigenicity of these particular human malignant cells of mesenchymal origin can be suppressed when fused with normal diploid fibroblasts. In addition, the results suggest that tumorigenicity in this system is chromosomal dosage dependent, since a diploid chromosomal complement from normal fibroblasts is capable of suppressing the tumorigenicity of a near-diploid but not a near-tetraploid chromosomal complement from the tumorigenic HT1080 parent. Finally, the loss of chromosome 1 (the chromosome to which the N-ras oncogene has been assigned) as well as chromosome 4 was correlated with the reappearance of tumorigenicity in the rare variant populations from otherwise nontumorigenic near-tetraploid hybrid cultures. Our results also suggest the possibility that tumorigenicity in these hybrids may be a gene dosage effect involving the number of activated N-ras genes in the hybrids compared to the gene(s) controlling the suppression of the activated N-ras genes.

Nonrandom chromosomal changes in untreated retinoblastomas

The karyotypic patterns of 15 retinoblastomas were examined. Five tumors were found to have two distinct stem lines and, therefore, the chromosomal patterns of 20 tumor cell lines are reported. Three nonrandom chromosomal changes, namely, a loss of a chromosome #13, the presence of an i(6p), or a trisomy of 1q were observed. The potential importance of these chromosomal changes in tumor development is discussed, particularly the loss of a chromosome #13 or the gain of an i(6p). At least one of the three chromosomal changes was found in 75% of the tumor lines analyzed.

A comparison of prostaglandin E2 gel and prostaglandin F2 alpha gel for preinduction cervical ripening

The unfavorable cervix remains a major obstacle to the successful induction of labor. Reported are results from an ongoing study of topical prostaglandin preparations used to effect preinduction cervical ripening. The current study compares the efficacy of 40 mg of prostaglandin (PG) F2 alpha versus 5 mg of PGE2, applied to the cervix in a methyltylose gel the night before attempted induction of labor. A prospective double-blind protocol was used similar to that which previously established the efficacy of the 5 mg of PGE2 preparation versus placebo at this institution. Results indicate the superiority of the PGE2 preparation as measured by change in Bishop score, Pitocin requirement, rate of cervical dilatation, and percentage of failed inductions. Cesarean section rates were similar in the two study groups, and no fetal or maternal morbidity was attributable to the preinduction ripening technique.

Cervical ripening with intravaginal prostaglandin E2 gel

Ripening of the cervix by intravaginal application of a prostaglandin-containing gel is evaluated. Thirty patients with an unfavorable cervix needing labor induction were studied in a double-blind, prospective fashion. The prostaglandin gel proved superior to placebo in ripening the cervix (P less than .05), reducing induction failures (P less than .025), diminishing the oxytocin dosage necessary for induction (P less than .05), and lowering the rate of cesarean section (.05 less than P less than .1). One hundred fifty additional patients with varying Bishop scores and differing clinical situations were also studied. There were 35 cesarean sections (23.3%), nine failed inductions (6%), a spontaneous labor rate of 46%, and an average Bishop score change of 2.5. Twenty patients with premature rupture of the membranes and an unfavorable cervix received a modified gel containing 2.5 mg of prostaglandin E2. Average Bishop score change was 2.9, and there was a 55% incidence of spontaneous labor.

Invasive properties of primary pediatric neoplasms in vitro

Primary solid tumors were mechanically and/or enzymatically disassociated, and the resulting suspensions of single cells and small clumps of cells were seeded onto three different substrates, i.e., tissue culture plastic, rat smooth muscle cells (SMCs), and SMC-derived extracellular matrix. Tests of the relative effectiveness of these substrates in supporting the survival and/or growth of ten different neoplasms demonstrated that only two explants remained viable for longer than 2 weeks when seeded onto tissue culture plastic while nine of the ten survived on biological substrates for 1 month or longer. Thus, tissue culture plastic was a poor substrate for primary pediatric neoplasms. In general, more than 80% of the most common solid neoplasms in childhood (brain tumor, neuroblastoma, renal tumor, rhabdomyosarcoma, osteogenic sarcoma, and Ewing's sarcoma) routinely survived or grew in long-term cultures when cultured onto SMCs or their matrix. Both substrates were effective in promoting survival and/or growth; however, cells of neuroblastomas and certain brain tumors showed a preference for a living smooth muscle substrate. Tumor cells maintained their characteristic cellular and subcellular morphology when compared with the histology of the in vivo neoplastic lesions. Light and electron microscopy of selected neoplasms cultured on SMCs for various time periods demonstrated areas of distinct cellular invasion and/or partial destruction of the SMC multilayers which correlated with the invasive potentials of the neoplasms in patients. Invasion and destruction of the SMCs were also noticed with quiescent tumor cell cultures, indicating that growth was not a necessary property of invasion. Several neoplasms were also capable of the degradation of connective tissue proteins as indicated by the hydrolysis of radiolabeled SMC matrices, but simple correlations between the extent of matrix degradation and invasive ability could not be drawn. The culture system described consistently provided for the survival and/or growth of the most common pediatric tumors for long time periods. Thus, basic biological properties of primary tumors, e.g., growth, invasive potentials, and differentiation capabilities, could be investigated routinely.

Routine growth and differentiation of primary retinoblastoma cells in culture

The lack of systems permitting the routine growth of primary retinoblastomas has been a hindrance in the study of basic properties of these neoplastic cells. Therefore, a new culture system has been developed in which all retinoblastomas, regardless of their origin (primary eye tumor and/or its metastasis, subcutaneous and/or intraocular xenograft from the nude mouse), showed consistent growth. Each tumor could be grown for an unlimited number of culture passages with the use of rat smooth muscle cell multilayers as a biologic substrate and human serum as a culture medium supplement. Several of the tumor lines were continuously grown for longer than 1 year. Labeling with [3H]thymidine for 16 hours demonstrated that between 15 and 40% of the retinoblastoma cells were labeled, depending on the individual neoplasm. Retinoblastomas were organized into clumps of cells that adhered to the smooth muscle cells. The tumor cells maintained a round morphology, and cell spreading was observed in only a few cases. Cultured retinoblastomas consistently showed spontaneous formation of well-differentiated Flexner-Wintersteiner rosettes if these structures were present in the primary eye tumor of the patient. Thus the culture system consistently permitted the growth of retinoblastomas and their photoreceptor cell differentiation.

Effects of free fatty acids, ethanol and development on gamma-aminobutyric acid and glutamate fluxes in rat nerve endings

The effects of type A (cis-unsaturated) and type B (trans-unsaturated and saturated) fatty acids, 1% and 3% ethanol (v/v), and development (7 days) on the thermodynamics of glutamate and gamma-aminobutyric acid (GABA) transport into cortical rat brain nerve endings were examined. The effects of the various manipulations, which are known to affect membrane fluidity, may be summarized. Three percent ethanol and oleic acid increased delta S degrees and delta S+ for glutamate transport and decreased delta H degrees and delta H+. Type B fatty acids had the opposite effects. In comparison to glutamate transport, GABA transport was less affected by the various manipulations and showed less specificity in terms of the fatty acid effects. Similarly, the effects of development on the thermodynamic parameters for glutamate and GABA transport were not consistent. Glutamate transport into 7-day nerve endings showed thermodynamic behavior similar to that seen when type A fatty acids were incorporated into adult nerve endings. In contrast, GABA transport into 7-day nerve endings had the character of adult nerve endings into which type B fatty acids were incorporated.

Tissue distribution of 3H-hematoporphyrin derivative in athymic "nude" mice heterotransplanted with human retinoblastoma

Quantitative uptake levels of tritium-labeled hematoporphyrin derivative (3H-HpD) have been obtained for normal and malignant tissue of athymic "nude" mice heterotransplanted intraocularly with human retinoblastoma. It was determined that eyes with tumor accumulated higher levels of 3H-HpD than those in control eyes. In addition, an improved therapeutic retention ratio of the drug (eyes with tumor compared with control eyes) was obtained at extended time intervals after administration.

Heteroploid conversion of human skin cells by methylcholanthrene

Cultured epithelial cells from human skin generally had 3- to 30-fold more hydrocarbon-metabolizing activity than fibroblasts from skin of the same donor. This activity was constant for up to 55 days in primary culture but was lost rapidly upon physical subdivision of the cultures. Treatment of primary mixed fibroblasts and epithelial cell cultures with methylcholanthrene, but not phenanthrene, led to development of actively growing fibroblastic cultures with many heteroploid cells. Unique marker chromosomes, stable over a number of cell population doublings, were identified in several of the heteroploid cell strains. Pure cultures of fibroblasts from the same donors did not undergo heteroploid conversion in response to methylcholanthrene. Spontaneously occurring heteroploidy in logarithmic phase human fibroblasts is a rare event; thus, heteroploid conversion may be a useful marker for chemical transformation of human cells. Because methylcholanthrene seems to have little transforming effect on human skin fibroblasts, human skin epithelial cells, because of their hydrocarbon-metabolizing activity, may serve to convert methylcholanthrene from a distal to an ultimate carcinogenic form.

Correlation between balance of specific chromosomes and expression of malignancy in hamster cells

Four 1-theta-D-arabinofuranosylcytosine (ara-C)-and one dimethylnitrosamine-transformed Syrian hamster cell lines were established. All produced tumors when inoculated into newborn hamsters. Specific chromosome changes were found in these lines consistent with changes observed recently by other investigators. Clones that had either high or low malignant potential were derived from two fibrosarcomas produced by one of the ara-C-transformed cell lines. The expression of malignancy in these clones was associated with an excess of 57 chromosomes over 73 chromosomes.