Association between Elevated Urine Neutrophil Gelatinase-Associated Lipocalin and Postoperative Acute Kidney Injury in Neonates

OBJECTIVE

To examine the incidence of postoperative neonatal acute kidney injury (AKI) following general surgical procedures and to test the hypothesis that postoperative urine neutrophil gelatinase-associated lipocalin (uNGAL) concentrations predict AKI. The secondary objective was to evaluate for an association between AKI and hospital mortality.

STUDY DESIGN

Prospective observational study of infants undergoing abdominal and thoracic surgical procedures in the neonatal intensive care unit from October 2018 to March 2020. The primary outcome was incidence of neonatal AKI (defined by the neonatal modified Kidney Diseases Improving Global Outcomes criteria) following each procedure to postoperative day 5. Severe AKI was defined as stage 2 or 3 AKI. Urine samples were obtained pre- and postoperatively at 6 time points to evaluate for levels of uNGAL. Secondary outcomes were in-hospital mortality and length of stay.

RESULTS

Subjects (n = 141) underwent a total of 192 general surgical procedures during the study period. Neonatal AKI and severe AKI occurred following 36 (18%) and 15 (8%) procedures (n = 33 subjects). Percent change of uNGAL from 24 hours preoperatively to 24 hours postoperatively was greater in subjects with neonatal AKI (190.2% [IQR 0.0, 1666.7%] vs 0.7% [IQR -31.2%,140.2%], P = .0374). The strongest association of uNGAL and AKI occurred at 24 hours postoperatively (area under the receiver operator curves of 0.81, 95% CI 0.72, 0.89). Increased mortality risk was observed in subjects with any postoperative AKI (aOR 11.1 95% CI 2.0, 62.8, P = .0063) and severe AKI (aOR 13.8; 95% CI 3.0, 63.1, P = .0007).

CONCLUSION

Elevation in uNGAL 24 hours postoperative was associated with AKI. Neonates with postoperative AKI had increased mortality.

No Evidence that Knops Blood Group Polymorphisms Affect Complement Receptor 1 Clustering on Erythrocytes

Clustering of Complement Receptor 1 (CR1) in the erythrocyte membrane is important for immune-complex transfer and clearance. CR1 contains the Knops blood group antigens, including the antithetical pairs Swain-Langley 1 and 2 (Sl1 and Sl2) and McCoy a and b (McC^a and McC^b), whose functional effects are unknown. We tested the hypothesis that the Sl and McC polymorphisms might influence CR1 clustering on erythrocyte membranes. Blood samples from 125 healthy Kenyan children were analysed by immunofluorescence and confocal microscopy to determine CR1 cluster number and volume. In agreement with previous reports, CR1 cluster number and volume were positively associated with CR1 copy number (mean number of CR1 molecules per erythrocyte). Individuals with the McC^b/McC^b genotype had more clusters per cell than McC^a/McC^a individuals. However, this association was lost when the strong effect of CR1 copy number was included in the model. No association was observed between Sl genotype, sickle cell genotype, α+thalassaemia genotype, gender or age and CR1 cluster number or volume. Therefore, after correction for CR1 copy number, the Sl and McCoy polymorphisms did not influence erythrocyte CR1 clustering, and the effects of the Knops polymorphisms on CR1 function remains unknown.

Strain variation in early innate cytokine induction by Plasmodium falciparum

Previous work has shown that human donors vary in the magnitude and pattern of cytokines induced when peripheral blood mononuclear cells (PBMCs) are co-cultured with Plasmodium falciparum–infected erythrocytes. Whether P. falciparum strains vary in their ability to induce cytokines has not been studied in detail and is an important question, because variation in cytokine induction could affect parasite virulence and patterns of clinical disease. We investigated the early inflammatory cytokine response to four P. falciparum laboratory strains and five field isolates. Initial studies showed that parasite strain, parasitaemia and PBMC donor all had significant effects on the magnitude of pro-inflammatory cytokine responses (IFN-γ, GM-CSF, IL-1β, TNF-α, IL-6, P < 0·005 in all cases). However, we noticed that the most highly inducing parasite strain consistently reached schizont rupture more rapidly than the other strains. When timing of schizont rupture was taken into account, parasite strains no longer differed in their cytokine induction (P = 0·383), although donor effects remained significant (P < 0·001). These data do not support the hypothesis that P. falciparum strains vary in induction of early innate cytokine responses from PBMCs, and instead are consistent with the suggestion that conserved parasite products such as haemozoin or GPI-anchors are the parasite-derived stimuli for cytokine induction.

Inter- and intra-specific cuticle variation between amphimictic and parthenogenetic species of root-knot nematode (Meloidogyne spp.) as revealed by a bacterial parasite (Pasteuria penetrans)

Specific host-parasite interactions exist between species and strains of plant parasitic root-knot nematodes and the Gram-positive bacterial hyperparasite Pasteuria penetrans. This bacterium produces endospores that adhere to the cuticle of migrating juveniles, germinate and colonise the developing female within roots. Endospore attachment of P. penetrans populations to second-stage juveniles of the root-knot nematode species Meloidogyne incognita and Meloidogyne hapla showed there were interactive differences between bacterial populations and nematode species. Infected females of M. incognita produced a few progeny which were used to establish two nematode lines from single infective juveniles encumbered with either three or 26 endospores. Single juvenile descent lines of each nematode species were produced to test whether cuticle variation was greater within M. hapla lines that reproduce by facultative meiotic parthenogenesis than within lines of M. incognita, which reproduces by obligate parthenogenesis. Assays revealed variability between broods of individual females derived from single second-stage juvenile descent lines of both M. incognita and M. hapla suggesting that progeny derived from a single individual can differ in spore adhesion in both sexual and asexual nematode species. These results suggest that special mechanisms that produced these functional differences in the cuticle surface may have evolved in both sexually and asexually reproducing nematodes as a strategy to circumvent infection by this specialised hyperparasite.

Erythrocyte complement receptor 1 (CR1) expression level is not associated with polymorphisms in the promoter or 3' untranslated regions of the CR1 gene

Complement receptor 1 (CR1) expression level on erythrocytes is genetically determined and is associated with high (H) and low (L) expression alleles identified by a HindIII restriction fragment-length polymorphism (RFLP) in intron 27 of the CR1 gene. The L allele confers protection against severe malaria in Papua New Guinea, probably because erythrocytes with low CR1 expression, are less able to form pathogenic rosettes with Plasmodium falciparum-infected erythrocytes. Despite the biological importance of erythrocyte CR1, the genetic mutation controlling CR1 expression level remains unknown. We investigated the possibility that mutations in the upstream or 3' untranslated regions of the CR1 gene could control erythrocyte CR1 level. We identified several novel polymorphisms; however, the mutations did not segregate with erythrocyte CR1 expression level or the H and L alleles. Therefore, high and low erythrocyte CR1 levels cannot be explained by polymorphisms in transcriptional control elements in the upstream or 3' untranslated regions of the CR1 gene.

A complement receptor-1 polymorphism with high frequency in malaria endemic regions of Asia but not Africa

Complement receptor-1 (CR1) is a ligand for rosette formation, a phenomenon associated with cerebral malaria (CM). Binding is dependent on erythrocyte CR1 copy number. In Caucasians, low CR1 expressors have two linked mutations. We determined the Q981H and HindIII RFLP distribution in differing population groups to ascertain a possible role in adaptive evolution. We examined 194 Caucasians, 180 Choctaw Indians, 93 Chinese-Taiwanese, 304 Cambodians, 89 Papua New Guineans (PNG) and 366 Africans. PCR/RFLP used HindIII for CR1 expression and BstNI for the Q981H mutation. DNA sequencing and pyrosequencing were performed to resolve inconclusive results. Gene frequencies for the L allele were 0.15 in Africans, 0.16 in Choctaws, 0.18 in Caucasians, 0.29 in Chinese-Taiwanese, 0.47 in Cambodians and 0.58 in PNG. Allelic frequency for 981H were 0.07 in Africans, 0.15 in Caucasians, 0.18 in Choctaws, 0.29 in Chinese-Taiwanese, 0.47 in Cambodians and 0.54 in PNG. The Q981H polymorphism correlates with the HindIII RFLP in most groups except West Africans and appears to be part of a low CR1 expression haplotype. The gene frequency for the haplotype is highest in the malaria-endemic areas of Asia, suggesting that this haplotype may have evolved because it protects from rosetting and CM.

Survey of a cDNA library from the turkey (Meleagris gallopavo)

Genome characterization and analysis is an imperative step in identifying and selectively breeding for improved traits of agriculturally important species. Expressed sequence tags (ESTs) represent a transcribed portion of the genome and are an effective way to identify genes within a species. Downstream applications of EST projects include DNA microarray construction and interspecies comparisons. In this study, 694 ESTs were sequenced and analyzed from a library derived from a 24-day-old turkey embryo. The 437 unique sequences identified were divided into 76 assembled contigs and 361 singletons. The majority of significant comparative matches occurred between the turkey sequences and sequences reported from the chicken. Whole genome sequence from the chicken was used to identify potential exon–intron boundaries for selected turkey clones and intron-amplifying primers were developed for sequence analysis and single nucleotide polymorphism (SNP) discovery. Identified SNPs were genotyped for linkage analysis on two turkey reference populations. This study significantly increases the number of EST sequences available for the turkey.Key words: turkey, cDNA, expressed sequence tag, single nucleotide polymorphism.

The role of Plasmodium falciparum var genes in malaria in pregnancy

Sequestration of Plasmodium falciparum-infected erythrocytes in the placenta is responsible for many of the harmful effects of malaria during pregnancy. Sequestration occurs as a result of parasite adhesion molecules expressed on the surface of infected erythrocytes binding to host receptors in the placenta such as chondroitin sulphate A (CSA). Identification of the parasite ligand(s) responsible for placental adhesion could lead to the development of a vaccine to induce antibodies to prevent placental sequestration. Such a vaccine would reduce the maternal anaemia and infant deaths that are associated with malaria in pregnancy. Current research indicates that the parasite ligands mediating placental adhesion may be members of the P. falciparum variant surface antigen family PfEMP1, encoded by var genes. Two relatively well-conserved subfamilies of var genes have been implicated in placental adhesion, however, their role remains controversial. This review examines the evidence for and against the involvement of var genes in placental adhesion, and considers whether the most appropriate vaccine candidates have yet been identified.

Identification of the Kna/Knb polymorphism and a method for Knops genotyping

BACKGROUND

DNA mutations resulting in the McCoy and Swain-Langley polymorphisms have been identified on complement receptor 1 (CR1)-a ligand for rosetting of Plasmodium falciparum-infected RBCs. The molecular identification of the Kna/Knb polymorphism was sought to develop a genotyping method for use in the study of the Knops blood group and malaria.

STUDY DESIGN AND METHODS

CR1 deletion constructs were used in inhibition studies of anti-Kna. PCR amplification of Exon 29 was followed by DNA sequencing. A PCR-RFLP was developed with NdeI, BsmI, and MfeI for the detection of Kna/Knb, McCa/McCb, and Sl1/Sl2, respectively. Knops phenotypes were determined with standard serologic techniques.

RESULTS

A total of 310 Malian persons were phenotyped for Kna with 200 (64%) Kn(a+) and 110 (36%) Kn(a-). Many of the Kn(a-) exhibited the Knops-null phenotype, that is, Helgeson. The Kna/b DNA polymorphism was identified as a V1561M mutation with allele frequencies of Kna (V1561) 0.9 and Knb (M1561) 0.1.

CONCLUSION

The high frequency (18%) of Knb in West African persons suggests that it is not solely a Caucasian trait. Furthermore, because of the high incidence of heterozygosity as well as amorphs, accurate Knops typing of donors of African descent is best accomplished by a combination of molecular and serologic techniques.

Microsatellite Loci for Genetic Mapping in the Turkey (Meleagris gallopavo)

New microsatellite loci for the turkey (Meleagris gallopavo) were developed from two small insert DNA libraries. Polymorphism at these new loci was examined in domestic birds and two resource populations designed for genetic linkage mapping. The majority of loci (152 of 168) was polymorphic in domestic turkeys and informative in two mapping resource populations and thus will be useful for genetic linkage mapping.

Turkey microsatellite loci from an embryonic cDNA library

Expressed sequence tags (EST) containing microsatellites have been used in the development of both genetic linkage maps and syntenic maps for various species and, thus, offer the advantage of being a convenient tool in comparative mapping studies. A turkey embryonic cDNA library was constructed and screened with (CA/TG)15, (GA/CT)15, (AGG)10, and (AAAC)7 probes for the development of polymorphic microsatellite markers. Sequences of 128 cDNA revealed 42 new loci containing microsatellites. BLAST nucleotide analysis demonstrated significant homology to known mammalian or avian coding regions for 15 of the turkey EST, five of which matched chicken transcripts. The remaining 27 EST represented novel sequences. Of the 42 new loci, 31 were polymorphic when tested on commercial turkey lines, including the founding individuals of a new resource population developed for genetic linkage mapping. Comparative mapping of these markers will provide new information toward the evolutionary divergence of turkey and chicken as well as other species.

A simple method for accurate quantification of complement receptor 1 on erythrocytes preserved by fixing or freezing

The mean number of complement receptor 1 (CR1) molecules on erythrocytes differs between normal individuals within the range of 100-1000 molecules per cell. In some disease states such as systemic lupus erythematosus (SLE), acquired immune deficiency syndrome (AIDS), insulin-dependent diabetes mellitus and malaria, erythrocyte CR1 levels are reduced and CR1 function may be impaired. Current methods for determining erythrocyte CR1 levels by flow cytometry require the use of freshly drawn blood samples because CR1 is lost from erythrocytes during storage. In order to facilitate field studies of associations between erythrocyte CR1 levels and disease, we have developed and validated an assay to quantify CR1 on both healthy and diseased erythrocytes that have been fixed in 5% formaldehyde or frozen in glycerol. These methods enable blood samples to be collected in areas lacking the facilities for flow cytometry and stored for later accurate quantification of CR1. Such procedures will be of particular benefit for future investigations of erythrocyte CR1 expression level and malaria susceptibility.

Twelve new turkey microsatellite loci

Microsatellite loci continue to be important tools in genetic analysis of populations and experimental families. Twelve new microsatellite sequences for the turkey were obtained from a small insert M13 library. Polymorphism at these new loci was examined in both domestic and wild birds. Seven of 12 loci were polymorphic in domestic turkeys, whereas 10 loci were polymorphic in our sample of wild birds.

Erythrocyte CR1 expression level does not correlate with a HindIII restriction fragment length polymorphism in Africans; implications for studies on malaria susceptibility

Complement receptor 1 (CR1) expression level on erythrocytes is genetically determined, and in Caucasian populations is linked to high (H) and low (L) expression alleles identified by a HindIII restriction fragment length polymorphism (RFLP). Erythrocyte CR1 may be an important factor in determining malaria susceptibility, as low expression of CR1 reduces the rosetting of uninfected erythrocytes with Plasmodium falciparum-infected cells, a process that contributes to malaria pathogenesis. Prior to studying CR1 expression and malaria susceptibility, we have investigated whether the quantity of erythrocyte CR1 correlates with the H and L alleles in an African population. Mean erythrocyte CR1 in 149 Malian adults was 415 molecules per cell, which is comparable to Caucasian populations; however, there was no relationship between erythrocyte CR1 level and genotype for the HindIII RFLP (mean CR1 per erythrocyte HH = 414, HL = 419 and LL = 403, P > 0.1, Student's t-test). The conclusions of a previous study of erythrocyte CR1 expression level and malaria susceptibility in West Africa that was based on HindIII RFLP genotyping may therefore need to be re-evaluated.

Molecular identification of Knops blood group polymorphisms found in long homologous region D of complement receptor 1

Complement receptor 1 (CR1) has been implicated in rosetting of uninfected red blood cells to Plasmodium falciparum-infected cells, and rosette formation is associated with severe malaria. The Knops blood group (KN) is located on CR1 and some of these antigens, ie, McCoy (McC) and Swain-Langley (Sl(a)), show marked frequency differences between Caucasians and Africans. Thus, defining the molecular basis of these antigens may provide new insight into the mechanisms of P falciparum malaria. Monoclonal antibody epitope mapping and serologic inhibition studies using CR1 deletion constructs localized McC and Sl(a) to long homologous repeat D of CR1. Direct DNA sequencing of selected donors identified several single nucleotide polymorphisms in exon 29 coding for complement control protein modules 24 and 25. Two of these appeared to be blood group specific: McC associated with K1590E and Sl(a) with R1601G. These associations were confirmed by inhibition studies using allele-specific mutants. A sequence-specific oligonucleotide probe hybridization assay was developed to genotype several African populations and perform family inheritance studies. Concordance between the 1590 mutation and McC was 94%; that between Sl(a) and 1601 was 88%. All but 2 samples exhibiting discrepancies between the genotype and phenotype were found to be due to low red cell CR1 copy numbers, low or absent expression of some alleles, or heterozygosity combined with low normal levels of CR1. These data further explain the variability observed in previous serologic studies of CR1 and show that DNA and protein-based genetic studies will be needed to clarify the role of the KN antigens in malaria.

Mapping of the region of complement receptor (CR) 1 required for Plasmodium falciparum rosetting and demonstration of the importance of CR1 in rosetting in field isolates

The malaria parasite Plasmodium falciparum induces a number of novel adhesion properties in the erythrocytes that it infects. One of these properties, the ability of infected erythrocytes to bind uninfected erythrocytes to form rosettes, is associated with severe malaria and may play a direct role in the pathogenesis of disease. Previous work has shown that erythrocytes deficient in complement receptor (CR) 1 (CR1, CD35; C3b/C4b receptor) have greatly reduced rosetting capacity, indicating an essential role for CR1 in rosette formation. Using deletion mutants and mAbs, we have localized the region of CR1 required for the formation of P. falciparum rosettes to the area of long homologous repeat regions B and C that also acts as the binding site for the activated complement component C3b. This result raises the possibility that C3b could be an intermediary in rosetting, bridging between the infected erythrocyte and CR1. We were able to exclude this hypothesis, however, as parasites grown in C3-deficient human serum formed rosettes normally. We have also shown in this report that rosettes can be reversed by mAb J3B11 that recognizes the C3b binding site of CR1. This rosette-reversing activity was demonstrated in a range of laboratory-adapted parasite strains and field isolates from Kenya and Malawi. Thus, we have mapped the region of CR1 required for rosetting and demonstrated that the CR1-dependent rosetting mechanism occurs commonly in P. falciparum isolates, and could therefore be a potential target for future therapeutic interventions to treat severe malaria.

Accountability: a fundamental component of nursing practice

The nursing care of the patient makes great demands on nurses' knowledge and skills; the care given must be competent, efficient and effective. In order to achieve this, nurses must have the necessary authority to manage and control their practice. This article seeks to examine the concept of accountability and relates its relevance to everyday nursing practice. A theoretical and critical incident approach is employed to demonstrate the principles surrounding accountability within nursing.

Rifins: a second family of clonally variant proteins expressed on the surface of red cells infected with Plasmodium falciparum

Many pathogens evade the host immune response or adapt to their environment by expressing surface proteins that undergo rapid switching. In the case of Plasmodium falciparum, products of a multigene family known as var are expressed on the surface of infected red cells, where they undergo clonal antigenic variation and contribute to malaria pathogenesis by mediating adhesion to a variety of host endothelial receptors and to uninfected red blood cells by forming rosettes. Herein we show that a second gene family, rif, which is associated with var at subtelomeric sites in the genome, encodes clonally variant proteins (rifins) that are expressed on the infected red cell surface. Their high copy number, sequence variability, and red cell surface location indicate an important role for rifins in malaria host-parasite interaction.

Retinal detachment in Olmsted County, Minnesota, 1976 through 1995

OBJECTIVE

To estimate the incidence of rhegmatogenous retinal detachment (RD) in a geographically defined population and to compare the probability of RD in residents after cataract extraction with the probability of RD in residents who did not have cataract extraction.

DESIGN

Rochester Epidemiology Project databases were used to perform a retrospective population-based incidence study of RD diagnosed between 1976 and 1995 with cohort analyses of the influence of risk factors on the occurrence of RD.

PARTICIPANTS

The population of Olmsted County, Minnesota, participated.

MAIN OUTCOME MEASURE

Incidence rates of RD adjusted to the age and gender distribution of the 1990 U.S. white population were measured.

RESULTS

Three hundred eleven incident cases of rhegmatogenous RD were identified. The mean annual age- and gender-adjusted incidence rate of rhegmatogenous RD was 17.9 per 100,000 persons (95% confidence interval [CI], 15.9-19.9). For idiopathic rhegmatogenous RD alone, the mean annual age- and gender-adjusted incidence rate was 12.6 (95% CI, 10.9-14.3) per 100,000 persons. Ten years after phacoemulsification and extracapsular cataract extraction, the estimated cumulative probability of RD was 5.5 (95% CI, 3.4-7.6) times as high as would have been expected in a similar group of county residents not undergoing cataract surgery.

CONCLUSIONS

Cataract surgery is associated with a significantly elevated long-term cumulative probability of retinal detachment.

Adverse side effects associated with latanoprost

PURPOSE

To report three different adverse reactions after initiating treatment with latanoprost.

METHOD

Serial clinical examinations of three patients were performed.

RESULTS

Adverse reactions such as ocular hypotony and choroidal effusions, recurrent cystoid macular edema, and facial rash were noted to occur within 1 to 4 weeks after starting topical latanoprost for the treatment of primary open-angle glaucoma.

CONCLUSION

Clinicians should be alerted to these possible complications of topical latanoprost therapy.

P. falciparum rosetting mediated by a parasite-variant erythrocyte membrane protein and complement-receptor 1

The factors determining disease severity in malaria are complex and include host polymorphisms, acquired immunity and parasite virulence. Studies in Africa have shown that severe malaria is associated with the ability of erythrocytes infected with the parasite Plasmodium falciparum to bind uninfected erythrocytes and form rosettes. The molecular basis of resetting is not well understood, although a group of low-molecular-mass proteins called rosettins have been described as potential parasite ligands. Infected erythrocytes also bind to endothelial cells, and this interaction is mediated by the parasite-derived variant erythrocyte membrane protein PfEMP1, which is encoded by the var gene family. Here we report that the parasite ligand for rosetting in a P. falciparum clone is PfEMP1, encoded by a specific var gene. We also report that complement-receptor 1 (CR1) on erythrocytes plays a role in the formation of rosettes and that erythrocytes with a common African CR1 polymorphism (S1(a-)) have reduced adhesion to the domain of PfEMP1 that binds normal erythrocytes. Thus we describe a new adhesive function for PfEMP1 and raise the possibility that CR1 polymorphisms in Africans that influence the interaction between erythrocytes and PfEMP1 may protect against severe malaria.

Triage assessment tool

The Triage Assessment Tool, although not meant to replace clinical judgment and experience, is designed to augment the decision making skills of the triage nurse. This is attained by focusing the user on the importance of sequence, and examination of pertinent data, thus ensuring a precise triage decision.

Tantrums: remediation through communication

There is a high correlation between behaviour problems, and lack of receptive and expressive language communication. Multiply handicapped children, with varying degrees of physical, mental, emotional, and sensory handicaps, in addition to a communication deficit, can learn a sign language system. Progress in communication through the sign language also results in substantial emotional and behavioural improvements. This paper presents two case studies of such children, and describes in detail the 7 year programme used to develop language through the Paget-Gorman sign system, with a profoundly deaf, subnormal, athetoid, disturbed boy.

Normal serum ferritin concentrations in precirrhotic hemochromatosis

We investigated 33 of 58 members of two families with latent or precirrhotic hemochromatosis to determine its pattern of inheritance and to evaluate the serum ferritin levels as an index of iron stores. In both families, the pattern of inheritance was as an autosomal dominant trait with incomplete expressivity. Mean serum ferritin values in the affected family members were 88.5 ng per milliliter (range, 28.0 to 201.9) for males and 65.2 ng per milliter (range 23.7 to 97.0) for females, which were no different from controls (P is less than 0.5). Furthermore, the serum ferritin values did not correlate with or reflect mobilizable iron stores, and there were no relations between the serum iron, iron-binding capacity and transferrin saturation (P is less than 0.2). Thus, serum ferritin concentrations in precirrhotic familial hemochromatosis appear to underestimate iron stores. Serum ferritin levels do not help to identify such patients with increased iron stores for therapeutic phlebotomy.

Adenine glycoside site of xanthosine-5'-phosphate aminase

Phosphonoacetic acid (PAA)-resistant type 1 herpes simplex virus population was isolated by repeated passage of the virus in the presence of this inhibitor. Hairless mice infected percutaneously with the inhibitor-resistant or the parental inhibitor-susceptible virus were treated intraperitoneally with PAA and 9-β-d-arabinofuranosyl-adenine by using several different dosage schedules. Whereas 9-β-d-arabinofuranosyl-adenine was effective both in the PAA-susceptible and PAA-resistant herpes simplex virus-induced skin infection, PAA suppressed only the infection induced by the parental PAA-susceptible virus.