Antibiotic Treatment of Suspected and Confirmed Neonatal Sepsis Within 28 Days of Birth: A Retrospective Analysis

Neonatal sepsis causes significant mortality and morbidity worldwide. Diagnosis is usually confirmed via blood culture results. Blood culture sepsis confirmation can take days and suffer from contamination and false negatives. Empiric therapy with antibiotics is common. This study aims to retrospectively describe and compare treatments of blood culture-confirmed and unconfirmed, but suspected, sepsis within the University of Utah Hospital system. Electronic health records were obtained from 1,248 neonates from January 1, 2006, to December 31, 2017. Sepsis was categorized into early-onset (≤3 days of birth, EOS) and late-onset (>3 and ≤28 days of birth, LOS) and categorized as culture-confirmed sepsis if a pathogen was cultured from the blood and unconfirmed if all blood cultures were negative with no potentially contaminated blood cultures. Of 1,010 neonates in the EOS cohort, 23 (2.3%) were culture-confirmed, most with Escherichia coli (42%). Treatment for unconfirmed EOS lasted an average of 6.1 days with primarily gentamicin and ampicillin while confirmed patients were treated for an average of 12.3 days with increased administration of cefotaxime. Of 311 neonates in the LOS cohort, 62 (20%) were culture-confirmed, most culturing coagulase negative staphylococci (46%). Treatment courses for unconfirmed LOS lasted an average of 7.8 days while confirmed patients were treated for an average of 11.4 days, these patients were primarily treated with vancomycin and gentamicin. The use of cefotaxime for unconfirmed EOS and LOS increased throughout the study period. Cefotaxime administration was associated with an increase in neonatal mortality, even when potential confounding factors were added to the logistic regression model (adjusted odds ratio 2.8, 95%CI [1.21, 6.88], p = 0.02). These results may not be generalized to all hospitals and the use of cefotaxime may be a surrogate for other factors. Given the low rate of blood culture positive diagnosis and the high exposure rate of empiric antibiotics, this patient population might benefit from improved diagnostics with reevaluation of antibiotic use guidelines.

Abstract P3-07-57: Development of a 6-gene qPCR RUO-validated assay as a predictive biomarker for response of vantictumab (OMP-18R5; anti-frizzled) in HER2- breast cancer patients

Background: We have developed a monoclonal antibody, vantictumab that blocks canonical WNT/β-catenin signaling through binding of five FZD receptors (1, 2, 5, 7, 8). This antibody inhibits the growth of several tumor types, including breast. Vantictumab reduces tumor-initiating cell frequency and exhibits synergistic activity with standard-of-care (SOC) agents (Gurney et al, 2012). To target breast cancer patients most likely to respond to vantictumab, we undertook a predictive biomarker study.

Methods: We have identified a 6-gene Wnt pathway-related signature, FBXW2, CCND2, RHOU, CTBP2, WIF1, and DKK1, based on microarray gene expression data from 8 breast cancer patient derived xenograft (PDX) models with established in vivo response to vantictumab plus SOC. This signature successfully predicted the response of 8 additional and independent PDX breast tumors. We further developed a qPCR Research Use Only (RUO) assay for the 6 genes to be used on FFPE human breast tumor samples. Multiple assays targeting different regions spanning each mRNA transcript were tested and selected based on PCR efficiency, specificity and sensitivity. We compared assay sensitivity under different cDNA synthesis and pre-amplification conditions: random vs. gene-specific priming, number of pre-amplification cycles, pre-amplification reaction volumes, and cDNA synthesis kits. A repeatability study was performed to test assay performance. The pre-amplification and PCR were repeated over three separate days and across two independent labs.

Results: Our results showed that cDNA synthesis by gene-specific priming followed by 18 cycles of pre-amplification performed the best and the assay is robust with minimal starting FFPE RNA input. The results of the repeatability study were consistent among the different days and the different labs (<5% CV). Using the 6-gene qPCR RUO assay, the signature score from the microarray data was further refined using 12 PDX HER2- breast tumors with known in vivo response to vantictumab with SOC. The prevalence of the 6-gene signature was established using ∼100 HER2- breast cancer samples.

Conclusions: A robust 6-gene RUO-validated assay was developed as a predictive biomarker for vantictumab in HER2- breast cancer. The assay is currently being evaluated in a Phase 1b study of vantictumab with paclitaxel in HER2- breast cancer.

Citation Format: Zhang C, O'Young G, Wikstrom K, Davison T, Yeung P, Cattaruzza F, Yen W-C, Hoey T, Lewicki J, Rachmann R, Kerr P, Hill L, Eason R, McErlean S, Liu Y, Kapoun AM. Development of a 6-gene qPCR RUO-validated assay as a predictive biomarker for response of vantictumab (OMP-18R5; anti-frizzled) in HER2- breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-57.

Single-transverse-mode Ti:sapphire rib waveguide laser

Laser operation of Ti:sapphire rib waveguides fabricated using photolithography and ion beam etching in pulsed laser deposited layers is reported. Polarized laser emission was observed at 792.5 nm with an absorbed pump power threshold of 265 mW, which is more than a factor of 2 lower in comparison to their planar counterparts. Measured beam propagation factors M2x and M2y of 1.3 and 1.2, respectively, indicated single-transverse-mode emission. A quasi-cw output power of 27 mW for an absorbed pump power of 1W and a slope efficiency of 5.3% were obtained using an output coupler of 4.6% transmission with a pump duty cycle of 8%.

Genetic immunization of chimpanzees chronically infected with the hepatitis B virus, using a recombinant retroviral vector encoding the hepatitis B virus core antigen

Cytotoxic T lymphocyte (CTL) activity and CD4+ helper T cell responses to the hepatitis B virus (HBV) core antigen (HBcAg) have been implicated in clearance of acute and chronic HBV infections. We showed that intramuscular injections of a novel recombinant retroviral vector expressing an HBcAg-neomycin phosphotransferase II (HBc-NEO) fusion protein induces HBc/eAg-specific antibodies and CD4+ and CD8+ T cell responses in mice and rhesus monkeys. We have now immunized three chronically infected chimpanzees, each with 10(10) CFU of nonreplicating retroviral vector particles expressing the HBc-NEO fusion protein. Of two immunized chimpanzees examined for CTL responses, one developed HBcAg-specific CTLs and showed marginal, transient elevations of alanine aminotransferase (ALT) levels following injection. However, both chimpanzees remained positive for serum HBeAg, negative for anti-HBe antibody by conventional assays, and displayed no change in HBV viral load throughout the study. In contrast, the third chimpanzee exhibited a traditional seroconversion evidenced by a loss of serum HBeAg and the subsequent emergence of anti-HBe antibodies within 24 weeks after the first injection. Simultaneously, two transient ALT flares and a significant decrease in the serum HBV DNA levels were noted. Despite its limitations, the present study demonstrates (1) the safety of treatment with high titers of retroviral vector in chimpanzees, (2) the capability of a retroviral vector expressing HBcAg to stimulate immune responses in HBV chronic carrier chimpanzees, and (3) that retroviral vector immunization may be therapeutically beneficial in the treatment of chronic HBV infection.

Stroke rehabilitation in south Auckland; the value of an effective rehabilitation unit

AIM

To assess the validity of Barthel based poststroke triage, the effectiveness of a rehabilitation unit in minimising poststroke institutionalisation, and medical resource utilisation for stroke management.

METHODS

A prospective study of stroke outcome for 115 consecutive patients admitted to Middlemore Hospital, Auckland, between March and September 1993, based on Barthel functional assessments at 1 week and 3 months poststroke, postdischarge domicile and duration of inpatient stay in both acute medical and rehabilitation units.

RESULTS

For the 73 patients offered rehabilitation, 48 (76%) of the survivors were able to return home after a mean period of 6 weeks. Of 24 subjects with 1 week Barthel scores of five or less, 15 of 19 (84%) survivors returned to their original domicile. Of eight patients with 1 week Barthel scores of two or less, all survived and five returned home. The median delay between admission by the acute medical service and transfer to the rehabilitation unit was only four days for the 70 patients involved.

CONCLUSION

Our data provides local confirmation of internationally increasing acceptance of the effectiveness of rehabilitation units in reducing expensive long term institutionalisation and freeing up stressed acute medical resources.

Tropical pyomyositis in the Solomon Islands: clinical and aetiological features

A prospective study of tropical pyomyositis (TP) in the Solomon Islands' Western Province followed 48 cases (mean age 10.6 years) from a population of 20,000 Melanesians over a two-year period. 32 patients were under 10 years and the male:female ratio was 1.7. Affected muscle was painful, swollen and often fluctuant but hard and indurated in presuppurative lesions. Abscesses, single in 40 and multiple in 8 subjects, were sited in the large muscles of the buttock, thigh, shoulder, arm and back on 52 occasions (90%). They contained 5-200 ml of pus which invariably grew penicillin-resistant Staphylococcus aureus sensitive to cloxacillin and erythromycin. All phage typable strains were identified as group 2 in contrast to the wider range of types found at carrier sites in otherwise healthy controls. TP was preceded by trauma in 30 cases (63%) and 26 (55%) of the patients had pre-existing pyoderma. Histological examination of clinically unaffected muscle biopsies from 10 subjects with solitary (7) or multiple (3) abscesses showed no abnormality. Serological evidence of previous infection with adenoviruses or myxoviruses was present in the same proportion (41-42%) of controls as of 22 patients tested. The results provide no evidence for antecedent diffuse myositis, viral or parasitic infections or nutritional deficiencies but support the role of trauma in localizing haematogenous skin staphylococci into damaged muscle.

The integration of habits maintained by food and water reinforcement through stimulus compounding

In Experiment 1, a light and a tone were correlated independently with water reinforcement of bar pressing by rats. With different naive subjects in Experiment 2, one of these stimuli was correlated with food and the other with water reinforcement (counterbalanced). In both experiments the absence of tone and light signaled extinction. Tests of stimulus-reinforcer independence in Experiment 2 indicated that tone and light controlled behavior whose rate was specifically affected by deprivation state. In the stimulus-compounding tests of both experiments, response rates were higher to tone-plus-light than to tone or light presented alone (additive summation). This is the first report of additive summation produced through compounding stimuli paired with different reinforcers. The results are discussed in the context of the effects of incentive motivation on operant performance.

CpG deficiency, dinucleotide distributions and nucleosome positioning

The dinucleotide CpG is deficient in (A + T)-rich regions of vertebrate DNA in both coding and non-coding sequences and there is a corresponding increase above expectation in the occurrence of TpG and CpA. By contrast in (G + C)-rich regions no deficiency of CpG is found. Such (G + C)-rich sequences, containing the expected number of CpG dinucleotides, alternate along the genome with (A + T)-rich sequences which have a lower than expected CpG content. The G + C content of vertebrate DNA can oscillate with a period of 150-200 bp and this may be a factor in positioning nucleosomes. The role of mutagenesis in loss of CpG and increase of A + T, particularly in non-coding regions, is discussed.

The efficiency of folding of some proteins is increased by controlled rates of translation in vivo. A hypothesis

We propose that the way in which some proteins fold is affected by the rates at which regions of their polypeptide chains are translated in vivo. Furthermore, we suggest that their gene sequences have evolved to control the rate of translational elongation such that the synthesis of defined portions of their polypeptide chains is separated temporally. We stress that many proteins are capable of folding efficiently into their native conformations without the help of differential translation rates. For these proteins the amino acid sequence does indeed contain all the information needed for the polypeptide chain to fold correctly (even in vitro, after denaturation). However, other proteins clearly do not fold efficiently into their native conformation in vitro. We argue that the efficiency of folding of these problematic proteins in vivo may be improved by controlled synthesis of the nascent polypeptide.

Isolation and characterization of latherin, a surface-active protein from horse sweat

A protein, latherin, with unusual surface activity was isolated from horse sweat by gel filtration and ion-exchange chromatography. The protein has a Stokes radius, determined by gel filtration, of 2.47 nm, and in the ultracentrifuge sediments as a single species with S20,W 2.05 S, indicating an Mr of 24,400. On SDS/polyacrylamide-gel electrophoresis the molecule behaves as a single peptide chain of apparent Mr 20,000. Latherin contains a high proportion of hydrophobic amino acids (37.2%), and the leucine content (24.5%) is exceptionally high. The unusual composition of the protein may account for apparent anomalies in the Mr of latherin determined by empirical methods. Evidence indicating that latherin is responsible for much of the surface activity of horse sweat was obtained by a simple assay for surface tension and by contact-angle measurements. Latherin adsorbs very readily at hydrophobic surfaces, rendering them wettable. A possible role for latherin in thermoregulation is proposed.

Increased G + C content of DNA stabilizes methyl CpG dinucleotides

The vertebrate genome is a mosaic of regions differing dramatically in their G + C content. Those regions with a high G + C content contain the expected number of CpG dinucleotides and we propose that following methylation these have been protected from deamination by the increased stability of the surrounding DNA duplex. This argument applies both to the microenvironment of the CpG dinucleotide and to whole gene regions.

Distinctions in variability of motor output between learning disabled and normal children

This study measured the differences in motor output between groups of 8- and 10-yr.-old learning disabled and normal boys. Variability of motor output was investigated by having children learn an alternating tapping task to a criterion of a specified number of taps per minute and then having them transfer to more difficult tapping tasks with the same rhythmic beat but requiring more distance to move or more accuracy. Results suggest variability of motor output distinguishes normal and learning disabled boys.

The crossed upgoing toe sign: a clinical study

We compared the crossed upgoing toe sign with the plantar response as an indicator of pyramidal tract dysfunction in 125 normal subjects and 192 patients with neurological disorders. A positive crossed upgoing toe sign was associated significantly with a partial pyramidal tract lesion in the contralateral cerebral hemisphere with a frequency similar to that of Babinski's sign. Unlike Babinski's sign, however, the positive crossed upgoing toe sign was lost when pyramidal weakness was severe enough to produce paralysis of voluntary dorsiflexion of the great toe, and it was found only rarely with pyramidal tract lesions of the spinal cord. The crossed upgoing toe sign has little value as a sensitive indicator of a pyramidal tract lesion. It is potentially of limited value as an aid in determining the level of a pyramidal tract lesion (cerebral hemisphere versus spinal cord), but its usefulness is seriously impaired by the high frequency of false positive signs in normal subjects and patients with other neurological disorders.

18S coding sequences in amplified ribosomal DNA from Xenopus laevis oocytes are highly homogeneous, unmethylated, and lack major open reading frames

We have used two approaches to search for sequence variants in the 18S coding region of amplified ribosomal DNA (rDNA) from Xenopus laevis oocytes. First, using clones derived from amplified rDNA, we compared the equivalent of a complete 18S coding region from two clones and short regions from two other clones with the 18S sequence previously determined from a "reference" clone. The respective sequences in all the clones were identical. Secondly, we examined greater than 60% of the 18S sequence in "pooled 18S genes" in uncloned amplified rDNA. The predominant sequence corresponded to that in the reference clone and no heterogeneities were apparent. Since many chromosomal rDNA units contribute to rDNA amplification the findings indicate that 18S coding sequences in X. laevis are largely homogeneous. The previously established sequence is the predominant one, thus providing a reliable basis for studies on 18S rRNA. Sequencing gels on uncloned amplified rDNA confirmed the absence of methylated cytosine in this DNA. The 18S sequence lacks major open reading frames.

The subunit structure of horse spleen apoferritin; the molecular weight of the oligomer and its stability to dissociation by dilution

The oligomer molecular weight of horse spleen apoferritin was determined by sedimentation-equilibrium techniques and a value of 443000 found. It is concluded that the apoferritin molecule consists of 24 subunits. At concentrations as low as 0.01mum there is no evidence of subunit dissociation.

Nucleoprotein complexes in simian virus 40-infected cells

When African green monkey kidney cells (BSC-1) were infected with simian virus 40 (SV40) and extracted with 0.25% Triton X-100 after exposure to (3)H-thymidine, the (3)H-SV40 deoxyribonucleic acid (DNA) was present in a form which had a sedimentation coefficient in sucrose gradients of 44S. The change from the sedimentation coefficient of purified SV40 DNA (21S) was shown to result from the association of the SV40 DNA in the Triton extracts with protein by means of sensitivity to Pronase digestion and labeling with (14)C-amino acids. Short-term labeling experiments with (3)H-thymidine demonstrated that SV40 DNA molecules in the course of replication (25S) were also present as nucleoprotein complexes in Triton-extracted material. Labeled DNA extracted with Triton in the form of nucleoprotein complexes was obtained in amounts which were quantitatively equivalent to the amounts extracted with deoxycholate in parallel experiments. This indicated that the newly synthesized pools of SV40 DNA may not occur as free DNA in the infected cell.

Superhelix density heterogeneity of intracellular simian virus 40 deoxyribonucleic acid

Covalently closed intracellular and viral simian virus 40 (SV40) deoxyribonucleic acid (DNA) were separately isolated from infected African green monkey cells (BSC-1) grown in culture. The two DNA species form overlapping bands centered at different positions in a propidium di-iodide-cesium chloride (PDI-CsCl) buoyant density gradient capable of separating closed DNA species with different superhelix densities. When the dense side of a (32)P-labeled intracellular DNA band was mixed with the light side of a (3)H-labeled intracellular DNA band and again centrifuged in a PDI-CsCl density gradient, two overlapping bands formed with modes displaced from each other. Similar band-splitting experiments performed with viral DNA always gave superimposable bands. The foregoing experiments demonstrate that the intracellular DNA is heterogeneous in superhelix density, whereas, by the same criteria, the viral DNA is homogeneous. The mean superhelix density of the intracellular closed DNA is approximately three-fourths as large as the superhelix density of the viral DNA. These results rule out the possibility that closed SV40 DNA is drawn randomly from the intracellular pool and assembled without a further nicking-closing step into virions. When the cells were grown and infected in the presence of ethidium bromide (EB), the intracellular closed DNA was found to be homogeneous in superhelix density and to have the same superhelix density as the viral DNA which, in turn, was unaffected by the presence of the drug. The foregoing results were explained by postulating that the intracellular DNA is formed with a homogeneous superhelix density and becomes heterogeneous in the absence of EB as a result of a nicking-closing cycle that occurs in a spacially or temporally heterogeneous environment. The drug EB would inhibit this action by inhibiting the nicking enzyme(s).