Effect of Early vs Late Inguinal Hernia Repair on Serious Adverse Event Rates in Preterm Infants: A Randomized Clinical Trial

Importance

Inguinal hernia repair in preterm infants is common and is associated with considerable morbidity. Whether the inguinal hernia should be repaired prior to or after discharge from the neonatal intensive care unit is controversial.

Objective

To evaluate the safety of early vs late surgical repair for preterm infants with an inguinal hernia.

Design, Setting, and Participants

A multicenter randomized clinical trial including preterm infants with inguinal hernia diagnosed during initial hospitalization was conducted between September 2013 and April 2021 at 39 US hospitals. Follow-up was completed on January 3, 2023.

Interventions

In the early repair strategy, infants underwent inguinal hernia repair before neonatal intensive care unit discharge. In the late repair strategy, hernia repair was planned after discharge from the neonatal intensive care unit and when the infants were older than 55 weeks' postmenstrual age.

Main Outcomes and Measures

The primary outcome was occurrence of any prespecified serious adverse event during the 10-month observation period (determined by a blinded adjudication committee). The secondary outcomes included the total number of days in the hospital during the 10-month observation period.

Results

Among the 338 randomized infants (172 in the early repair group and 166 in the late repair group), 320 underwent operative repair (86% were male; 2% were Asian, 30% were Black, 16% were Hispanic, 59% were White, and race and ethnicity were unknown in 9% and 4%, respectively; the mean gestational age at birth was 26.6 weeks [SD, 2.8 weeks]; the mean postnatal age at enrollment was 12 weeks [SD, 5 weeks]). Among 308 infants (91%) with complete data (159 in the early repair group and 149 in the late repair group), 44 (28%) in the early repair group vs 27 (18%) in the late repair group had at least 1 serious adverse event (risk difference, -7.9% [95% credible interval, -16.9% to 0%]; 97% bayesian posterior probability of benefit with late repair). The median number of days in the hospital during the 10-month observation period was 19.0 days (IQR, 9.8 to 35.0 days) in the early repair group vs 16.0 days (IQR, 7.0 to 38.0 days) in the late repair group (82% posterior probability of benefit with late repair). In the prespecified subgroup analyses, the probability that late repair reduced the number of infants with at least 1 serious adverse event was higher in infants with a gestational age younger than 28 weeks and in those with bronchopulmonary dysplasia (99% probability of benefit in each subgroup).

Conclusions and Relevance

Among preterm infants with inguinal hernia, the late repair strategy resulted in fewer infants having at least 1 serious adverse event. These findings support delaying inguinal hernia repair until after initial discharge from the neonatal intensive care unit.

Trial Registration

ClinicalTrials.gov Identifier: NCT01678638.

Factors that impact second attempt success for neonatal intubation following first attempt failure: a report from the National Emergency Airway Registry for Neonates

OBJECTIVE

To determine the factors associated with second attempt success and the risk of adverse events following a failed first attempt at neonatal tracheal intubation.

DESIGN

Retrospective analysis of prospectively collected data on intubations performed in the neonatal intensive care unit (NICU) and delivery room from the National Emergency Airway Registry for Neonates (NEAR4NEOS).

SETTING

Eighteen academic NICUs in NEAR4NEOS.

PATIENTS

Neonates requiring two or more attempts at intubation between October 2014 and December 2021.

MAIN OUTCOME MEASURES

The primary outcome was successful intubation on the second attempt, with severe tracheal intubation-associated events (TIAEs) or severe desaturation (≥20% decline in oxygen saturation) being secondary outcomes. Multivariate regression examined the associations between these outcomes and patient characteristics and changes in intubation practice.

RESULTS

5805 of 13 126 (44%) encounters required two or more intubation attempts, with 3156 (54%) successful on the second attempt. Second attempt success was more likely with changes in any of the following: intubator (OR 1.80, 95% CI 1.56 to 2.07), stylet use (OR 1.65, 95% CI 1.36 to 2.01) or endotracheal tube (ETT) size (OR 2.11, 95% CI 1.74 to 2.56). Changes in stylet use were associated with a reduced chance of severe desaturation (OR 0.74, 95% CI 0.61 to 0.90), but changes in intubator, laryngoscope type or ETT size were not; no changes in intubator or equipment were associated with severe TIAEs.

CONCLUSIONS

Successful neonatal intubation on a second attempt was more likely with a change in intubator, stylet use or ETT size.

Implementing bubble continuous positive airway pressure in a lower middle-income country: a Nigerian experience

Bubble CPAP (bCPAP) is used for respiratory distress (RD) in neonates. The leading causes of neonatal mortality can lead to severe RD. Many neonatal deaths are preventable using evidence-based interventions like bCPAP as part of a comprehensive approach. The study aimed to assess the implementation of a multi-center, comprehensive hospital-based bCPAP program in a low-middle-income country using a low-cost bCPAP device. Seven established hospitals in three Nigerian States were selected using purposive sampling. A respiratory support program was developed and implemented using the Pumani® bCPAP. Neonates <28 days old with severe RD, birth weight >1000g and breathing spontaneously, were eligible. The program lasted 22 months. Focus group discussions and in-depth interviews of healthcare workers and hospital administrators were used in program assessment. Content analysis of qualitative data completed. The staff reported that the bCPAP device was easy to use and effective. All staff reported comfort in eligible patient identification, effective set up and bCPAP administration. All study sites experienced varying degrees of electric power interruption and oxygen availability and affordability. Staff training, staffing disruptions, data collection challenges and use of improvised bCPAP contributed to low enrollment. Advocacy, direct program support, and innovation using locally available resources improved enrollment. Professional organization collaboration, competency-based training and peer mentoring contributed to program success. Thorough pre-program assessment, with comprehensive understanding of all aspects of the existing system within the local context which are likely to impact the introduction of a new program is important to implementation success.

Transmitted Home Oximetry and Duration of Home Oxygen in Premature Infants

OBJECTIVES

To determine if a home oxygen therapy (HOT) management strategy that includes analysis of recorded home oximetry (RHO) data, compared with standard monthly clinic visit assessments, reduces duration of HOT without harm in premature infants.

METHODS

The RHO trial was an unmasked randomized clinical trial conducted in 9 US medical centers from November 2013 to December 2017, with follow-up to February 2019. Preterm infants with birth gestation ≤37 + 0/7 weeks, discharged on HOT, and attending their first pulmonary visit were enrolled. The intervention was an analysis of transmitted RHO between clinic visits (n = 97); the standard-care group received monthly clinic visits with in-clinic weaning attempts (n = 99). The primary outcomes were the duration of HOT and parent-reported quality of life. There were 2 prespecified secondary safety outcomes: change in weight and adverse events within 6 months of HOT discontinuation.

RESULTS

Among 196 randomly assigned infants (mean birth gestational age: 26.9 weeks; SD: 2.6 weeks; 37.8% female), 166 (84.7%) completed the trial. In the RHO group, the mean time to discontinue HOT was 78.1 days (SE: 6.4), compared with 100.1 days (SE: 8.0) in the standard-care group (P = .03). The quality-of-life scores improved from baseline to 3 months after discontinuation of HOT in both groups (P = .002), but the degree of improvement did not differ significantly between groups (P = .75).

CONCLUSIONS

RHO was effective in reducing the duration of HOT in premature infants. Parent quality of life improved after discontinuation. RHO allows physicians to determine which infants can be weaned and which need prolonged oxygen therapy between monthly visits.

Neonatal early onset sepsis in Middle Eastern countries: a systematic review

BACKGROUND

Early onset neonatal sepsis (EOS) accounts for a significant portion of neonatal mortality, which accounts for 46% of global under five child mortality.

OBJECTIVE

This systematic review studies the bacterial aetiology of EOS in the Middle East, susceptibility patterns to recommended empirical antibiotic therapy and whether this differs between high-income and middle-income countries in the region.

METHODS

Articles were collected from Medline, Web of Science, the Cochrane Library and Index Medicus for the Eastern Mediterranean Region. The articles included in our systematic review met the following criteria: published after January 2000, data relevant to the Middle East, data specific for early onset sepsis, no language restriction. Data on aetiology and susceptibility were extracted from prospective and retrospective studies. Risk of bias was assessed using the Newcastle-Ottawa Scale. This study focused on EOS but does include data regarding neonatal late-onset sepsis antibiotic susceptibility. The data regarding coagulase-negative Staphylococcus species were excluded from final analysis, as possible contaminants. The protocol for this systematic review was registered on PROSPERO: CRD42017060662.

RESULTS

33 articles from 10 countries were included in the analysis. There were 2215 cases of culture-positive EOS, excluding coagulase-negative Staphylococcus. In middle-income countries, Klebsiella species (26%), Staphylococcus aureus (17%) and Escherichia coli (16%) were the most common pathogens, in contrast to group B Streptococcus (26%), E. coli (24%) and Klebsiella (9%) in high-income countries. Overall susceptibility to ampicillin/gentamicin and third-generation cephalosporin were 40% and 37%, respectively, in middle-income countries versus 93% and 91%, respectively, in high-income countries.

CONCLUSIONS

EOS in middle-income countries was more likely to be due to Gram-negative pathogens and less likely to be susceptible to empirical antibiotic therapy. This has important public health implications regarding neonatal mortality in the Middle East region.

Agronomic Factors Associated with Bacterial Leaf Streak Development Caused by Xanthomonas vasicola pv. vasculorum in Corn

In 2016, the bacterium Xanthomonas vasicola pv. vasculorum was reported causing bacterial leaf streak on Nebraska corn. Prior to this report, the pathogen was reported on corn only in South Africa. Hence, there was a lack of information about the effects of corn production practices on bacterial leaf streak development. A survey of growers, crop consultants, extension agents, and others in the field of agriculture was initiated during the 2016 and 2017 corn growing seasons to examine agronomic factors that may affect the disease. Survey respondents were asked to submit a symptomatic leaf sample for pathogen confirmation via polymerase chain reaction, along with a completed survey on corn production practices. Analyses of 325 survey responses via random forest analysis indicated that irrigation, planting date, and crop rotation were the three most important predictors of corn samples testing positive for X. vasicola pv. vasculorum. According to a classification and regression tree analysis, irrigation use, the V7-R2 range of crop stages, multiple years of corn in a crop rotation or a corn-sorghum rotation, and planting dates after 2 May, were most closely associated with corn samples testing positive for X. vasicola pv. vasculorum. χ² tests of independence indicated that applications of nitrogen fertilizer and glyphosate herbicide use may also be related to bacterial leaf streak development.

Alternative Hosts in the Families Poaceae and Cyperaceae for Xanthomonas vasicola pv. vasculorum, Causal Agent of Bacterial Leaf Streak of Corn

The bacterial pathogen Xanthomonas vasicola pv. vasculorum was first reported in the United States causing bacterial leaf streak on Nebraska corn (Zea mays) in 2016. The bacterium is also known to cause disease in sugarcane, grain sorghum, broom bamboo, and various palm species. The objective of this study was to identify alternative hosts for X. vasicola pv. vasculorum among plants commonly found in corn growing areas of the United States. In repeated greenhouse experiments, 53 species of plants found in the United States that had not been tested previously for susceptibility to X. vasicola pv. vasculorum were inoculated with the pathogen and monitored for symptom development. Eleven species in the family Poaceae exhibited symptoms: oat (Avena sativa), rice (Oryza sativa), orchardgrass (Dactylis glomerata), indiangrass (Sorghastrum nutans), big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), timothy (Phleum pratense), sand bluestem (Andropogon hallii), green foxtail (Setaria viridis), bristly foxtail (Setaria verticillata), and johnsongrass (Sorghum halepense). Yellow nutsedge (Cyperus esculentus) in the Cyperaceae also was a symptomatic host. In addition, endophytic colonization by X. vasicola pv. vasculorum was found in three asymptomatic alternative hosts: downy brome (Bromus tectorum), tall fescue (Festuca arundinacea), and western wheatgrass (Pascopyum smithii). Experiments were also conducted in the field to determine the potential for alternative hosts to become infected by natural inoculum. Symptoms developed only in big bluestem and bristly foxtail in field experiments. These results suggest that infection of alternative hosts by X. vasicola pv. vasculorum can occur, but infection rates might be limited by environmental conditions.

Bubble CPAP therapy for neonatal respiratory distress in level III neonatal unit in Amman, Jordan: a prospective observational study

PURPOSE

Bubble continuous positive airway pressure (bCPAP), a noninvasive respiratory support modality used to manage newborns with respiratory distress, provides continuous pressure that helps prevent derecruitment of alveoli, increasing the lungs' functional residual capacity, and thus decreasing the work of breathing. bCPAP can be used to manage various respiratory conditions in the newborn. In this prospective study, we describe our experience using bCPAP therapy as the primary respiratory support in a level III neonatal unit in Amman, Jordan. In addition to reporting therapeutic indications, durations, and side effects, we aimed to identify areas requiring improvement in bCPAP therapy in our population.

PATIENTS AND METHODS

This prospective observational study investigated the usage of bCPAP in the management of respiratory distress in newborns admitted to a Jordan University Hospital in Amman. The newborns were followed until discharge. The patients' demographic and clinical data were recorded.

RESULTS

A total of 143 babies (mean gestational age, 36±2.7 weeks; mean birth weight, 2,770±1,800 g) were included. All received bCPAP as the primary respiratory support. The most common underlying cause of respiratory distress was transient tachypnea of the newborn (42%), followed by prolonged respiratory transition (34%). The therapy success rate was 93.7%; only nine infants failed bCPAP. The most common side effect was physical facial injury.

CONCLUSION

The use of neonatal bCPAP therapy is well established in Jordan University Hospital. The area of potential improvement was the low rate of bCPAP use as a primary respiratory support in extremely premature infants.

The optimization of home oxygen weaning in premature infants trial: Design, rationale, methods, and lessons learned

Improved survival among preterm infants has led to an increase in diagnosis of chronic lung disease and infants discharged home from the NICU on supplemental oxygen. Despite this increased prevalence, no clearly defined guidelines for the management of home oxygen therapy (HOT) exist. This lack of consensus leads to significant variability in the duration of home oxygen therapy and a general paucity of evidence-based practice. Our team has identified recorded home oxygen therapy (RHO) as a potential new resource to guide clinical decision making in the outpatient pulmonology clinic. By recording extended O2 saturation data during the weaning process, RHO has the potential to save cost and improve the processes of HOT management. Our team is currently supporting a prospective, multi-center, randomized, controlled trial of RHO guided HOT weaning with the aims of determining effect upon duration of HOT, perceived parent quality of life and effect upon growth and respiratory outcomes. We plan to randomize 196 infants into one of two study arms evaluating standard HOT management versus RHO guided oxygen weaning. Our primary outcomes are total HOT duration and parental quality of life. This trial represents an unprecedented opportunity to test a novel home monitoring intervention for weaning within a vulnerable yet quickly growing population. If effective, the use of RHO may provide clinicians a tool for safe weaning.

Detection and Characterization of Xanthomonas vasicola pv. vasculorum (Cobb 1894) comb. nov. Causing Bacterial Leaf Streak of Corn in the United States

Bacterial leaf streak of corn (Zea mays) recently reached epidemic levels in three corn-growing states, and has been detected in another six states in the central United States. Xanthomonas vasicola was identified as the causal agent of this disease. A multilocus sequence alignment of six housekeeping genes and comparison of average nucleotide identity from draft genome sequence were used to confirm phylogenetic relationships and classification of this bacteria relative to other X. vasicola strains. X. vasicola isolates from Nebraska and South Africa were highly virulent on corn and sugarcane and less virulent on sorghum but caused water-soaking symptoms that are typical of X. vasicola infection on the leaves of all three hosts. Based on host range and phylogenetic comparison, we propose the taxonomic designation of this organism to X. vasicola pv. vasculorum ( Cobb 1894 ) comb. nov. Polymerase chain reaction-based diagnostic assays were developed that distinguish X. vasicola pv. vasculorum and X. vasicola pv. holcicola from each other and from other Xanthomonas spp.

A defect in myoblast fusion underlies Carey-Fineman-Ziter syndrome

Multinucleate cellular syncytial formation is a hallmark of skeletal muscle differentiation. Myomaker, encoded by Mymk (Tmem8c), is a well-conserved plasma membrane protein required for myoblast fusion to form multinucleated myotubes in mouse, chick, and zebrafish. Here, we report that autosomal recessive mutations in MYMK (OMIM 615345) cause Carey-Fineman-Ziter syndrome in humans (CFZS; OMIM 254940) by reducing but not eliminating MYMK function. We characterize MYMK-CFZS as a congenital myopathy with marked facial weakness and additional clinical and pathologic features that distinguish it from other congenital neuromuscular syndromes. We show that a heterologous cell fusion assay in vitro and allelic complementation experiments in mymk knockdown and mymk^insT/insT zebrafish in vivo can differentiate between MYMK wild type, hypomorphic and null alleles. Collectively, these data establish that MYMK activity is necessary for normal muscle development and maintenance in humans, and expand the spectrum of congenital myopathies to include cell-cell fusion deficits.

Photoemission of cooper pairs from aromatic hydrocarbons

We report the discovery of the formation of an electron Cooper pair approximately 40 eV above the double-ionization threshold in benzene, naphthalene, anthracene, and coronene after absorption of a single photon. We have measured the ratios of doubly to singly charged parent ions of the above mentioned molecules as well as pyrrole and furan by using monochromatized synchrotron radiation up to 100 eV above the corresponding thresholds. We also recorded photoelectron spectra of benzene and naphthalene at selected energies. The electron-pair formation is based on the specific structure of the molecules and does not exist for pyrrole and furan.

Large molecules reveal a linear length scaling for double photoionization

We have measured the ratio of doubly to singly charged parent ions of benzene, naphthalene, anthracene, and pentacene using monochromatized synchrotron radiation up to 30 eV above the corresponding threshold. Our measurements show a striking similarity between the ratio of doubly charged to all parent ions and the ratio for helium. Moreover, the magnitudes of the ratios for these molecules scale linearly with their lengths with an amazing accuracy. A high ratio, i.e., a high relative double-photoionization probability, makes a molecule an important source of low-energy electrons that can promote radiation damage of biomolecules [B. Boudaïffa et al., Science 287, 1658 (2000)].

Weight and body composition changes during and after adjuvant chemotherapy in women with breast cancer

Uncontrolled trials have reported significant weight gain in women with breast cancer during treatment with adjuvant chemotherapy. We prospectively evaluated body composition before (visit 1), immediately after (visit 2), and 6 months after (visit 3) chemotherapy in 20 women with stages I-IIIA breast cancer [body mass index (BMI): 24.1 +/- 3.9 kg/m(2)]. We compared their weight change to 51 age- and BMI-matched healthy controls (BMI: 25.5 +/- 3.8 kg/m(2)). In women with breast cancer, there was no weight change from visit 1-2, or from visit 1-3, but weight increased from visit 2-3 (+1.09 +/- 2.46 kg; P = 0.05). Weight change was not different from controls during either interval. In the breast cancer group, the percentage of body fat assessed by air displacement plethysmography increased, and fat-free mass decreased from visit 1-2 (+2.3 +/- 4% and -2.2 +/- 4%; P = 0.02) and from visit 1-3 (+4.0 +/- 6% and -3.8 +/- 6%; P = 0.01). By dual energy x-ray absorptiometry, the percentage of body fat increased from visit 2-3 (+0.9 +/- 1.6%; P = 0.02). Bone mineral content decreased from visit 2-3 (-0.02 +/- 0.04 kg; P = 0.02) and from visit 1-3 (-0.04 +/- 0.06 kg; P = 0.005). By computed tomography, the visceral adipose to sc adipose tissue ratio decreased from visit 1-3 (-0.02 +/- 0.05 ml; P = 0.02). We conclude that, compared with controls, women with breast cancer receiving modern adjuvant chemotherapy regimens show no significant changes in weight during the first year of their treatment. They do, however, appear to undergo unfavorable changes in body composition.

Preovulatory treatment of mice with anti-VEGF receptor 2 antibody inhibits angiogenesis in corpora lutea

Adult mammalian angiogenesis occurs predominantly in female reproductive organs: the ovary and the uterus. Angiogenesis is very active during corpus luteum formation. A key regulator of angiogenesis is vascular endothelial growth factor (VEGF), which is highly expressed during corpus luteum formation. Inhibition of VEGF activity can block the formation and function of the corpora lutea by preventing angiogenesis. The VEGF receptor 2 (VEGF-R2) mediates the angiogenic action of VEGF and is expressed during corpus luteum formation. We hypothesized that treatment with an antibody against VEGF-R2 would inhibit luteal angiogenesis by blocking VEGF/VEGF-R2 interaction. Immature mice were induced to superovulate with PMSG/hCG resulting in neovascularization in the corpora lutea, as evidenced by abundant staining for the endothelial-specific adhesion molecule PECAM. Multiple doses of a monoclonal antibody against the VEGF-R2 (DC101) were administered to immature mice. Treatment was initiated 2 days prior to the induction of superovulation with PMSG/hCG. This antibody inhibited luteal angiogenesis as evidenced by the lack of PECAM staining in the center of the corpora lutea. Multiple dose treatment with antibody initiated prior to gonadotropin administration could not dissociate the luteal inhibition from the consequences of inhibition of angiogenesis in the developing follicle. Administration of a single, preovulatory dose of anti-VEGF-R2 antibody, such that follicular angiogenesis would not be affected, also inhibited luteal development, demonstrating that luteal angiogenesis is required for corpus luteal development. We conclude that VEGF acting through VEGF-R2 has an obligatory role in luteal angiogenesis and corpus luteum formation.

Hypomethylation of p53 in peripheral blood DNA is associated with the development of lung cancer

Alterations in DNA methylation have been associated with cancers at almost all tumor sites and represent one of the most consistent changes in neoplastic cells. The underlying etiological mechanisms for alteration of DNA methylation patterns are not understood, but experimental studies in animals suggest potential environmental and genetic influences. The purpose of this study was to investigate whether DNA hypomethylation in peripheral blood DNA (potentially representing status at the lung) was associated with increased risk for the development of lung cancer. We evaluated genome-wide and p53 gene-specific hypomethylation in 100 lung cancer cases and controls selected from a large clinical trial of male smokers, the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Genome-wide methylation status was assessed using the in vitro methyl acceptance capacity assay and p53 gene-specific methylation status using the HpaII quantitative PCR assay. Hypomethylation was evaluated as a risk factor using multivariate conditional logistic regression analyses. Genome-wide methylation status was unrelated to lung cancer risk; the odds ratio was 1.25 and the 95% confidence interval was 0.48-3.21 for those in the highest versus lowest quartile of hypomethylation status. Hypomethylation of the p53 gene in exons 5-8, the hypermutable region, was associated with a 2-fold increased risk for lung cancer (odds ratio, 2.20; 95% confidence interval, 1.04-4.65), whereas there was no risk increase for hypomethylation at exons 2-4, a region of the gene not known for its mutability or functional significance in cancer. Our results indicate that hypomethylation status within exons 5-8 of p53 from peripheral lymphocyte DNA may be a relevant predictor of lung cancer among male smokers.

Pds5p is an essential chromosomal protein required for both sister chromatid cohesion and condensation in Saccharomyces cerevisiae

The PDS5 gene (precocious dissociation of sisters) was identified in a genetic screen designed to identify genes important for chromosome structure. PDS5 is an essential gene and homologues are found from yeast to humans. Pds5p function is important for viability from S phase through mitosis and localizes to chromosomes during this cell cycle window, which encompasses the times when sister chromatid cohesion exists. Pds5p is required to maintain cohesion at centromere proximal and distal sequences. These properties are identical to those of the four cohesion complex members Mcd1p/Scc1p, Smc1p, Smc3p, and Scc3p/Irr1p (Guacci, V., D. Koshland, and A. Strunnikov. 1997. Cell. 91:47-57; Michaelis, C., R. Ciosk, and K. Nasmyth. 1997. Cell. 91:35-45; Toth, A., R. Ciosk, F. Uhlmann, M. Galova, A. Schleiffer, and K. Nasmyth. 1999. Genes Dev. 13:307-319). Pds5p binds to centromeric and arm sequences bound by Mcd1p. Furthermore, Pds5p localization to chromosomes is dependent on Mcd1p. Thus, Pds5p, like the cohesin complex members, is a component of the molecular glue that mediates sister chromatid cohesion. However, Mcd1p localization to chromosomes is independent of Pds5p, which may reflect differences in their roles in cohesion. Finally, Pds5p is required for condensation as well as cohesion, which confirms the link between these processes revealed through analysis of Mcd1p (Guacci, V., D. Koshland, and A. Strunnikov. 1997. Cell. 91:47-57). Therefore, the link between cohesion and condensation is a general property of yeast chromosomes.

Radiation doses to the cell nucleus in single cells and cells in micrometastases in targeted therapy with (131)I labeled ligands or antibodies

PURPOSE

The aim of this study was to theoretically investigate how the radiation dose to cell nuclei depends on the subcellular position of (131)I. The influence of the size of the cells and crossfire irradiation in clusters of cells was also studied.

METHODS AND MATERIAL

Using data describing the dose rate around a point source of (131)I, we calculated the dose distributions inside and around cell models of different sizes. The assumed positions of (131)I were on the cellular or nuclear membrane, in the cytoplasm, in the nucleus, or spread in the whole cell. The mean doses to the nucleus of the targeted cell and to the nuclei of its neighbors were calculated using the dose distributions.

RESULTS

The dose distributions inside a single targeted cell showed very different distribution profiles depending on the subcellular position of the (131)I. Targeting the nucleus instead of the cellular membrane could increase the dose to the nucleus 10-fold. Crossfire irradiation can be the major contributor to the nuclear dose in clusters of more than six cells.

CONCLUSIONS

Dosimetry without microscopic considerations is inadequate for targeted radionuclide therapy of disseminated or clustering tumor cells exposed to (131)I. Therapeutic doses could be achieved, even in single cells, when (131)I was positioned near, or inside the cell nucleus, or when the clusters were large enough.

Serum tocopherols, selenium and lung cancer risk among tin miners in China

OBJECTIVE

To evaluate the association of prediagnostic serum antioxidants and lung cancer risk we conducted a case-control study nested in an occupational cohort of tin miners.

METHODS

Male workers free of cancer enrolled in the cohort. During up to 6 years of follow-up, 339 lung cancer cases were diagnosed and, among these cases, those who donated blood prospectively (n = 108) were eligible for this study. For each case, two controls alive and free of cancer at the time of case diagnosis were matched on age and date of blood collection.

RESULTS

Overall, we observed no association between serum alpha-tocopherol, gamma-tocopherol or selenium levels and lung cancer risk. However, a significant gradient of decreasing lung cancer risk with increasing serum alpha-tocopherol was apparent for men less than 60 years old (odds ratio by tertile: 1.0, 0.9, 0.2; trend p = 0.002). Alpha-tocopherol was also protective in men who reported no alcohol drinking (OR by tertile: 1.0, 0.6, 0.3; trend p = 0.008).

CONCLUSION

Although there were no significant overall associations between prospectively collected serum alpha-tocopherol, gamma-tocopherol or selenium and incidence of lung cancer, results from this study suggest that higher alpha-tocopherol levels may be protective in men less than 60 years old and in those who do not drink alcohol.

Uptake, toxicity and radiation effects of the boron compounds DAAC-1 and DAC-1 in cultured human glioma cells

PURPOSE

To study the uptake, toxicity and radiation effects in vitro of a diol-amino acid-carborane (DAAC-1) and make comparisons with the previously studied diol-amine-carborane (DAC-1).

MATERIALS AND METHODS

Toxicity and radiation effects were studied with clonogenic survival, uptake by measuring the cellular boron content and the subcellular distribution was investigated after organelle separation with centrifugation. The studied cell line was human glioma U343.

RESULTS

DAAC-1 showed an accumulation of 1-1.5 times, compared with the culture medium, and was non-toxic up to 47 microg boron/ml. The accumulation of DAC-1 was about 90 times, but toxic effects were detectable already at the concentration 5 microg boron/ml. None of the compounds was localized in the cell nucleus. Following irradiation with thermal neutrons, DAC-1 was about 2.5 times more effective than DAAC-1 and about 4.9 times more effective than neutrons alone, at the survival level 0.2. The dose modifying factors, when compared with the neutron beam alone, were for both DAAC-1 and DAC-1 about 1.5 and about 5 when compared with 60Co-gamma-radiation.

CONCLUSIONS

DAAC-1 was less toxic than DAC-1 but gave less accumulation of boron. Both substances gave significant boron-dependent cell inactivation when the test cells were exposed to thermal neutrons.

A peptide derived from neutrophil inhibitory factor (NIF) blocks neutrophil adherence to endothelial cells

OBJECTIVE AND DESIGN

Peptides derived from neutrophil inhibitory factor (NIF), a known antagonist of Mac-1, were evaluated as inhibitors of neutrophil adherence.

MATERIAL

In vitro assays of adherence employed: 1) human polymorphonuclear cells (PMN), 2) human umbilical vein endothelial cells (HUVEC), and 3) CHO cells expressing ICAM-1 (CHO-ICAM cells).

TREATMENT

Cells, pretreated with NIF-derived peptides (0.1-100 microM) for 10 minutes, were permitted to adhere for 20 min in the continued presence of peptide.

METHODS

Cell-based assays: 1) PMN adherence to HUVEC, 2) PMN adhesion to immobilized human serum proteins, and 3) adherence of CHO-ICAM cells to immobilized Mac-1.

RESULTS

A NIF-derived peptide of 29 amino acids blocked PMN adherence to HUVEC, but behaved somewhat differently than the parent NIF protein. NIF specifically antagonized Mac-1 dependent adherence, but the peptide blocked neutrophil adherence that was dependent upon both Mac-1 and LFA-1 integrins. CHO-ICAM adherence to Mac-1 was blocked by NIF, but not by the peptide. Binding studies with NIF and the peptide indicate that the molecules bind to different sites.

CONCLUSIONS

A peptide derived from NIF blocks PMN adherence but, unlike NIF, the mechanism of action is not mediated by direct antagonism Mac-1.

Chemistry and biology of some low molecular weight boron compounds for boron neutron capture therapy

Boronated DNA targeting agents are especially attractive candidates for BNCT because they may deliver boron-10 to the nuclei of tumor cells. Numerous boron-containing analogs have been synthesized and some have shown promising results in initial biological tests. One of the most challenging tasks in this special field of research remains the finding of suitable targeting strategies for the selective delivery of boron rich DNA-intercalator/alkylator to tumor cells. Synthetic and biological studies of boron compounds suitable for DNA-binding are reviewed. The amino acid p-boronophenylalanine (BPA) is presently of considerable clinical interest. Other boronated amino acids might also be candidates for BNCT either per se, as part of part of tumor-seeking peptides or conjugated to targeting macromolecules. A large number of boronated L- and D-amino acids with varying liphophicility and sterical requirements are now available for evaluation. Recent synthetic and biological studies of aromatic boronoamino acids, carboranylamino acids and carboranyl amines are also reviewed.

Rejoining of DNA double-strand breaks induced by accelerated nitrogen ions

Rejoining of radiation-induced DNA double-strand breaks (dsb) was measured in cultured cells with pulsed-field gel electrophoresis after radiation doses in the range of 5-30 Gy. Human glioma, U-343MG and Chinese hamster, V79, cells were irradiated with either accelerated nitrogen ions of high linear energy transfer, LET approximately 125 keV/ microns, or photons from 60Co. The induction frequencies of dsb were similar for the two radiation qualities with a relative biological effectiveness, RBE, of 0.90 and 0.89 for the human and hamster cell lines respectively. The biphasic rejoining kinetics differed significantly between the two radiation qualities when studied in the human glioma cells. The difference was seen within the first hour after irradiation and after 6 h there were considerable differences in both the total amount of unrejoined dsb and the fraction of dsb rejoined during the slow phase. When rejoining was analysed 20-22 h after irradiation, the nitrogen ions gave 2.5-2.9 times more residual dsb than the gamma photons. The results for the hamster V79 cells were, up to 2h after irradiation, similar, but the difference between the two radiation qualities was less accentuated. In summary, similar initial yields of dsb after exposure of cells to high or low LET resulted in both radiation quality and cell type-dependent differences when the rejoining of these breaks were compared.

In vitro determination of toxicity, binding, retention, subcellular distribution and biological efficacy of the boron neutron capture agent DAC-1

In boron neutron capture therapy (BNCT), 10B is delivered selectively to the tumour cells and the nuclide then forms high-LET radiation (4He2+ and 7Li3+) upon neutron capture. Today much research is focused on development of a variety of boron compounds aimed for BNCT. The compounds must be thoroughly analysed in preclinical tests regarding basic characteristics such as binding and subcellular distribution to enable accurate estimations of dose-modifying factors. DAC-1,2-[2-(3-amino-propyl)-1,2-dicarba-closo-dodecaboran (12)-1-yl-methoxy]- 1,3-propanediol was synthesized at our laboratories and the human colon carcinoma cells LS-174T were used as an in vitro model. The boron compound showed a remarkable intracellular accumulation, 20-100 times higher than the boron content in the culture medium, in cultured cells and was not removed by extensive washes. Approximately half of the boron taken up also remained within the cells for at least 4 days. The DAC-1 compound alone was not toxic at boron concentrations below 2.5 micrograms B/g. The intracellular distribution of the boron compound was investigated by subcellular fractionation experiments and low pH treatments. It is possible that DAC-1 binds to some intracellular molecules or to membranes connected with organelles in the cytoplasm or even to the inside of the outer cell membrane. Another possibility is that the compound, due to the somewhat lipophilic properties, is embedded in the membranes. Thermal neutron irradiations were carried out at the Brookhaven Medical Research Reactor (BMRR). At a survival level of 0.1, DAC-1 + thermal neutrons were about 10.5 times more effective in cell inactivation than the thermal neutrons alone. Monte Carlo calculations gave a mean value of the 10B-dependent specific energy, the dose, of 0.22 Gy. The total physical dose during irradiation of DAC-1-containing cells with a neutron fluence of 0.18 x 10(12) n/cm2 was 0.39 Gy. The dose-modifying factor, at survival level 0.1, when comparing irradiation with thermal neutrons with and without DAC-1 was 3.4, while the dose-modifying factor when comparing neutron irradiations of cells with DAC-1 and irradiation of the cells with 60Co-gamma was 7.3. The results are encouraging and in vivo tests of tissue distributions and tumour uptake should now be carried out.

Radioimmunotherapy of prostatic adenocarcinomas: effects of 131I-labelled E4 antibodies on cells at different depth in DU 145 spheroids

Spheroids of the human prostatic adenocarcinoma cell line DU 145 were used to study experimental radioimmunotherapy. Spheroids were incubated with the 131I-labelled monoclonal E4 antibody until the radionuclide immunoconjugate had bound the 5 to 6 outermost cell layers of the spheroids. A set of 50 spheroids were exposed, either immediately or 48 hr after antibody incubation and washings, to a dilute trypsin solution with the aim of stripping off cells from the spheroid surface. Stripped cells were collected in fractions corresponding to defined spherical shells. Cells were subsequently plated for clonogenic growth. The technique of automated sequential trypsinization of spheroids followed by a clonogenic survival assay permits studies on therapeutic efficacy for radionuclide immunoconjugates on cells from different layers of spheroids. In addition, the absorbed doses throughout a spheroid were calculated. The binding and retention kinetics of the radionuclide immunoconjugate and the excess of 131I-E4 in the culture medium during incubation are factors that were all accounted for in the calculations. If the calculated absorbed doses were inserted into the linear-quadratic survival model and the low dose rate was taken into account, survival values were well in accordance with the experimentally obtained values. The results demonstrate that the 131I-labelled E4 antibody is capable of sterilizing cultured tumour cells that have bound the radionuclide immunoconjugate and, by means of radiation "cross-fire", those cells located in close proximity.

A comparison of the efficacy and complication rates of low dose-rate versus high dose-rate brachytherapy in the treatment of uterine cervical carcinoma

PURPOSE

To compare the outcome and complication rates for treatment of uterine cervical carcinoma with low dose-rate (LDR) vs. high dose-rate (HDR) brachytherapy at the University of Wisconsin Comprehensive Cancer Center (UWCCC).

METHODS AND MATERIALS

One-hundred ninety-eight evaluable patients with cervical carcinoma, Stages IB to IIIB, treated with curative intent with a combination of megavoltage teletherapy and LDR brachytherapy from 1977 to 1988 were the subject of an initial review. In 1989, a HDR treatment program was initiated where all patients with cervical carcinoma were subsequently treated with a combination of HDR brachytherapy and teletherapy. Using the linear-quadratic model (LQ), the dose and schedule of HDR brachytherapy and teletherapy were designed to give similar tumor control and late effects as LDR therapy. Technically, the HDR schedule required meticulous attention to treatment geometry to limit severe late effects. Forty patients treated with the HDR program with 2-4 year follow-up were reviewed and compared to the previous LDR patient group. The LDR and HDR treatment groups were comparable with regards to age, weight, stage distribution, bulk of disease, and histology.

RESULTS

No significant difference in survival was found between the LDR and HDR groups with 3-year actuarial overall survival being 66% and 77%, respectively. Three-year actuarial pelvic control rates were similar at 80% and 77% for the LDR and HDR groups, respectively. No significant difference in late treatment complications requiring hospitalization or surgery was found between the two treatment groups with a complication rate of 10% (20/198) for the LDR patients and 2.5% (1/40) for the HDR patients.

CONCLUSION

As predicted by our LQ calculations, treatment results for LDR and HDR brachytherapy were similar with respect to survival, pelvic control and late complications in the treatment of cervical carcinoma. The HDR brachytherapy program at the UWCCC appears to be a safe and effective alternative to LDR therapy in the treatment of cervical carcinoma.

Strategy for boron neutron capture therapy against tumor cells with over-expression of the epidermal growth factor-receptor

PURPOSE

Gliomas, squamous carcinomas and different adenocarcinomas from breast, colon and prostate might have an increased number of epidermal growth factor (EGF) receptors. The receptors are, in these cases, candidates for binding of receptor specific toxic conjugates that might inactivate cellular proliferation. The purpose of this study was to evaluate whether it is reasonable to try ligand-dextran based conjugates for therapy.

METHODS AND MATERIALS

EGF or TGF alpha were conjugated to dextran and binding, internalization, retention and degradation of eight types of such conjugates were analyzed in EGF-receptor amplified glioma cells. The conjugates were labelled with radioactive nuclides to allow detection and two of the conjugates were carrying boron in the form of carboranyl amino acids or aminoalkyl-carboranes. Comparative binding tests, applying 125I-EGF, were made with cultured breast, colon and prostate adenocarcinoma, glioma and squamous carcinoma cells. Some introductory tests to label with 76Br for positron emission tomography and with 131I for radionuclide therapy were also made.

RESULTS

The dextran part of the conjugates did not prevent receptor specific binding. The amount of receptor specific binding varied between the different types of conjugates and between the tested cell types. The dextran part improved intracellular retention and radioactive nuclides were retained for at least 20-24 h. The therapeutical effect improved when 131I was attached to EGF-dextran instead of native EGF.

CONCLUSION

The improved cellular retention of the ligand-dextran conjugates is an important property since it gives extended exposure time when radionuclides are applied and flexibility in the choice of time for application of neutrons in boron neutron capture therapy (BNCT). It is possible that ligand-dextran mediated BNCT might allow, if the applied neutron fields covers rather wide areas around the primary tumor, locally spread cells that otherwise would escape treatment to be inactivated.

Radiation dose heterogeneity in receptor and antigen mediated boron neutron capture therapy

Boron neutron capture therapy, BNCT, might be a valuable tumour therapeutical modality for the treatment of cells that are difficult to handle with conventional methods such as surgery or external radiotherapy. The principle is that tumour associated 10B atoms capture thermal neutrons and thereby forms high-LET helium and lithium ions as reaction products. An interesting development is to conjugate 10B atoms to macromolecules that bind to tumour cells with over-expressed receptors or specific antigens. The targeting macromolecules might be receptor-ligands, antibodies or antibody-fragments containing 10B. The present study deals with the limitations of such an approach. One problem is the background dose from capture of neutrons in physiologically occurring elements, especially nitrogen. We showed, with computer simulations, that the background specific energy (the stochastic analogy of dose) in the cell nuclei, due to captures in nitrogen, had a wide spread and could be rather high, up to 3 Gy in some cells, when relevant neutron fluencies were applied. The maximal amount of 10B that can be delivered to single tumour cells due to receptor-ligand, receptor-antibody or antigen-antibody mediated binding is probably in the range 10(8)-10(10) atoms/cell. Our calculations showed that the tumour cells had to contain about 10(9) 10B/cell to give a therapeutically interesting dose to the nuclei of the targeted cells. The doses were highest when the boron was in the cell nucleus. There was also a wide spread of specific energy absorbed by the nuclei after neutron capture in 10B. When, for example, 10(8) 10(10)B/nucleus were applied the specific energy to the analysed nuclei varied from 0 Gy up to about 7 Gy. These variations were due to the stochastic nature of the capture processes. Some helium or lithium ion tracks passed through the centre of the cell nuclei delivering a lot of energy, some passed through only a smaller part delivering small amounts of energy and sometimes the nuclei escaped without any hits at all. The results were obtained when relevant neutron fluencies (2-5 x 10(12) n/cm2) were applied. Increased neutron fluencies gave higher doses both due to capture in boron and in nitrogen but in order to improve the ratio between the dose to targeted tumour cells and the dose to normal cells, the number of 10B atoms in the targeted cells had to be increased and/or the boron placed in the cell nuclei.

Dose enhancement in fast neutron tumour therapy due to neutron captures in 10B

High energy neutrons, applied in fast neutron tumour therapy, lose energy when passing through tissue and are at the end of their trajectories captured in nitrogen, hydrogen or other normally occurring elements. If the tissue contains 10B, which has a very high cross section for capture of thermal neutrons, then disintegration products of this process, helium and lithium ions, give a dose enhancement which, if the boron is targeted to tumour cells, may be beneficial. The dose enhancement was in the present study calculated as a function of the 10B concentration in the cells and as a function of different thermal neutron fluencies. If the tumour cells contained 10 or 100 microns 10B/g the average dose enhancement was about 20 or 200 mGy respectively. This was obtained with the thermal neutron fluency 2.0 x 10(10) n/cm2. The relative biological effectiveness of the neutron capture process is unknown but assuming the factor 2, these doses correspond to 0.04 or 0.4 CGE (cobolt-60 gray equivalent) respectively, which could directly be compared to the 2-3 Gy of low-LET radiation that is daily applied in conventional radiotherapy. However, if thermal or epithermal neutron fields are directly applied to the patients a hundred times higher thermal neutron fluency can be used. This gives, in the cases with 10 or 100 micrograms 10B/g, about a hundred times higher average doses so that 2-20 Gy, corresponding to about 4-40 CGE, can be given to the patients. Thus, a successful targeting with high amounts of 10B in the tumour cells gives a significant dose enhancement when applied in fast neutron therapy but it is then more reasonable to treat the patient directly with thermal or epithermal neutrons since the average dose enhancement in the latter case is about a hundred times higher and curable doses might be obtained by the tumour specific capture processes alone.

NPC 16377, a potent and selective sigma-ligand. II. Behavioral and neuroprotective profile

6-[6-(4-Hydroxypiperidinyl)hexyloxy]-3-methylflavone HCI, (NPC 16377), a potent and highly selective sigma-site ligand, was evaluated in tests predictive of antipsychotic and neuroprotective potential and for toxicity. Like haloperidol, clozapine and remoxipride, and the sigma-ligands BMY 14802, ifenprodil and rimcazole, NPC 16377 reversed amphetamine-induced hyperactivity and apomorphine-induced climbing in mice. Additional evidence for antipsychotic activity was obtained in rats with NPC 16377, clozapine, BMY 14802, ifenprodil, haloperidol and rimcazole, all of which reduced conditioned avoidance responses at doses that did not reduce escape behavior. NPC 16377 did not induce catalepsy in mice, suggesting a decreased liability for producing extrapyramidal side effects. NPC 16377 extended survival time for mice exposed to a hypoxic environment. In a model of global ischemia using conscious gerbils, NPC 16377 prevented damage to hippocampal CA1 neurons after either intraperitoneal or oral administration. NPC 16377 did not disrupt prepulse inhibition or block the disruption of prepulse inhibition induced by the phencyclidine site-selective ligand (+)MK-801. In rats trained to discriminate phencyclidine from saline, NPC 16377 did not substitute for the psychotomimetic. These data are consistent with the notion that selective sigma-agents may possess antipsychotic and neuroprotective activities. Moreover, the results from prepulse inhibition and drug discrimination experiments suggest that NPC 16377 is devoid of phencyclidine-like effects.

Effects of strychnine-insensitive glycine receptor antagonists and sigma agents on working memory performance: comparison with dizocilpine and scopolamine

The strychnine insensitive glycine receptor antagonists (+/-) HA 966 (2.5, 3.5, 4.25 and 5.0mg/kg) and 7 chlorokynurenic acid (5.0, 10.0, and 15.0mg/kg), the putative sigma agents NPC 16377 (5.0 and 8.0mg/kg), BMY 14802 (5.0, 7.5 and 10.0mg/kg), and ifenprodil (5.0 and 7.0mg/kg) and the reference agents scopolamine and dizocilpine [(+) MK 801] were evaluated in a nonspatial delayed matching to sample working memory task in rats. (+/-) HA 966 impaired accuracy at the longest retention interval and decreased response probability measures. 7-Chlorokynurenic acid was essentially without effect. The noncompetitive NMDA antagonist dizocilpine reduced accuracy at all retention intervals, decreased the probability of a choice response and increased the probability of an intertrial interval response. The anticholinergic agent scopolamine selectively reduced accuracy at the longest retention interval but did not affect other performance measures. Sigma agents decreased response probability measures but did not affect accuracy at any retention interval. The results support the notion that sigma agents, glycine antagonists and NMDA antagonists produce different effects in cognitive tasks including working memory performance.

The human gene for vascular endothelial growth factor. Multiple protein forms are encoded through alternative exon splicing

Vascular endothelial growth factor (VEGF) is an apparently endothelial cell-specific mitogen that is structurally related to platelet-derived growth factor. By Northern blot and protein analyses, we show that VEGF is produced by cultured vascular smooth muscle cells. Analysis of VEGF transcripts in these cells by polymerase chain reaction and cDNA cloning revealed three different forms of the VEGF coding region, as had been reported in HL60 cells. The three forms of the human VEGF protein chain predicted from these coding regions are 189, 165, and 121 amino acids in length. Comparison of cDNA nucleotide sequences with sequences derived from human VEGF genomic clones indicates that the VEGF gene is split among eight exons and that the various VEGF coding region forms arise from this gene by alternative splicing: the 165-amino-acid form of the protein is missing the residues encoded by exon 6, whereas the 121-amino-acid form is missing the residues encoded by exons 6 and 7. Analysis of the VEGF gene promoter region revealed a single major transcription start, which lies near a cluster of potential Sp1 factor binding sites. The promoter region also contains several potential binding sites for the transcription factors AP-1 and AP-2; consistent with the presence of these sites, Northern blot analysis demonstrated that the level of VEGF transcripts is elevated in cultured vascular smooth muscle cells after treatment with the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate.