A Comprehensive Study of the Effects by Sequence Truncation within Inverted Terminal Repeats (ITRs) on the Productivity, Genome Packaging, and Potency of AAV Vectors

One of the primary challenges in working with adeno-associated virus (AAV) lies in the inherent instability of its inverted terminal repeats (ITRs), which play vital roles in AAV replication, encapsidation, and genome integration. ITRs contain a high GC content and palindromic structure, which occasionally results in truncations and mutations during plasmid amplification in bacterial cells. However, there is no thorough study on how these alterations in ITRs impact the ultimate AAV vector characteristics. To close this gap, we designed ITRs with common variations, including a single B, C, or D region deletion at one end, and dual deletions at both ends of the vector genome. These engineered ITR-carrying plasmids were utilized to generate AAV vectors in HEK293 cells. The crude and purified AAV samples were collected and analyzed for yield, capsid DNA-filled percentage, potency, and ITR integrity. The results show that a single deletion had minor impact on AAV productivity, packaging efficiency, and in vivo potency. However, deletions on both ends, except A, showed significant negative effects on the above characteristics. Our work revealed the role of ITR regions, A, B, C, and D for AAV production and DNA replication, and proposes a new strategy for the quality control of ITR-bearing plasmids and final AAV products.

AAV-based gene therapy prevents and halts the progression of dilated cardiomyopathy in a mouse model of phosphoglucomutase 1 deficiency (PGM1-CDG)

Phosphoglucomutase 1 (PGM1) deficiency is recognized as the third most common N-linked congenital disorders of glycosylation (CDG) in humans. Affected individuals present with liver, musculoskeletal, endocrine, and coagulation symptoms; however, the most life-threatening complication is the early onset of dilated cardiomyopathy (DCM). Recently, we discovered that oral D-galactose supplementation improved liver disease, endocrine, and coagulation abnormalities, but does not alleviate the fatal cardiomyopathy and the associated myopathy. Here we report on left ventricular ejection fraction (LVEF) in 6 individuals with PGM1-CDG. LVEF was pathologically low in most of these individuals and varied between 10% and 65%. To study the pathobiology of the cardiac disease observed in PGM1-CDG, we constructed a novel cardiomyocyte-specific conditional Pgm2 gene (mouse ortholog of human PGM1) knockout (Pgm2 cKO) mouse model. Echocardiography studies corroborated a DCM phenotype with significantly reduced ejection fraction and left ventricular dilation similar to those seen in individuals with PGM1-CDG. Histological studies demonstrated excess glycogen accumulation and fibrosis, while ultrastructural analysis revealed Z-disk disarray and swollen/fragmented mitochondria, which was similar to the ultrastructural pathology in the cardiac explant of an individual with PGM1-CDG. In addition, we found decreased mitochondrial function in the heart of KO mice. Transcriptomic analysis of hearts from mutant mice demonstrated a gene signature of DCM. Although proteomics revealed only mild changes in global protein expression in left ventricular tissue of mutant mice, a glycoproteomic analysis unveiled broad glycosylation changes with significant alterations in sarcolemmal proteins including different subunits of laminin-211, which was confirmed by immunoblot analyses. Finally, augmentation of PGM1 in KO mice via AAV9-PGM1 gene replacement therapy prevented and halted the progression of the DCM phenotype.

Multiple phases of human occupation in Southeast Arabia between 210,000 and 120,000 years ago

Changing climatic conditions are thought to be a major control of human presence in Arabia during the Paleolithic. Whilst the Pleistocene archaeological record shows that periods of increased monsoon rainfall attracted human occupation and led to increased population densities, the impact of arid conditions on human populations in Arabia remains largely speculative. Here, we present data from Jebel Faya in Southeast (SE) Arabia, which document four periods of human occupation between c. 210,000 and 120,000 years ago. The Jebel Faya record indicates that human occupation of SE Arabia was more regular and not exclusively linked to major humid periods. Our data show that brief phases of increased rainfall additionally enabled human settlement in the Faya region. These results imply that the mosaic environments in SE Arabia have likely formed a population refugia at the end of the Middle and the beginning of the Late Pleistocene.

Arabinosylation of recombinant human immunoglobulin-based protein therapeutics

Protein glycosylation is arguably the paramount post-translational modification on recombinant glycoproteins, and highly cited in the literature for affecting the physiochemical properties and the efficacy of recombinant glycoprotein therapeutics. Glycosylation of human immunoglobulins follows a reasonably well-understood metabolic pathway, which gives rise to a diverse range of asparagine-linked (N-linked), or serine/threonine-linked (O-linked) glycans. In N-linked glycans, fucose levels have been shown to have an inverse relationship with the degree of antibody-dependent cell-mediated cytotoxicity, and high mannose levels have been implicated in potentially increasing immunogenicity and contributing to less favorable pharmacokinetic profiles. Here, we demonstrate a novel approach to potentially reduce the presence of high-mannose species in recombinant human immunoglobulin preparations, as well as facilitate an approximate 100% replacement of fucosylation with arabinosylation in Chinese hamster ovary cell culture through media supplementation with D-arabinose, an uncommonly used mammalian cell culture sugar substrate. The replacement of fucose with arabinose was very effective and practical to implement, since no cell line engineering or cellular adaptation strategies were required. Arabinosylated recombinant IgGs and the accompanying reduction in high mannose glycans, facilitated a reduction in dendritic cell uptake, increased FcγRIIIa signaling, and significantly increased the levels of ADCC. These aforementioned effects were without any adverse changes to various structural or functional attributes of multiple recombinant human antibodies and a bispecific DVD-Ig. Protein arabinosylation represents an expansion of the N-glycan code in mammalian expressed glycoproteins.

No effect of host-parasite co-evolution on host range expansion

Antagonistic co-evolution between hosts and parasites (reciprocal selection for resistance and infectivity) is hypothesized to play an important role in host range expansion by selecting for novel infectivity alleles, but tests are lacking. Here, we determine whether experimental co-evolution between a bacterium (Pseudomonas fluorescens SBW25) and a phage (SBW25Φ2) affects interstrain host range: the ability to infect different strains of P. fluorescens other than SBW25. We identified and tested a genetically and phenotypically diverse suite of co-evolved phage variants of SBW25Φ2 against both sympatric and allopatric co-evolving hosts (P. fluorescens SBW25) and a large set of other P. fluorescens strains. Although all co-evolved phage had a greater host range than the ancestral phage and could differentially infect co-evolved variants of P. fluorescens SBW25, none could infect any of the alternative P. fluorescens strains. Thus, parasite generalism at one genetic scale does not appear to affect generalism at other scales, suggesting fundamental genetic constraints on parasite adaptation for this virus.

Effect of PI3K- and mTOR-specific inhibitors on spontaneous B-cell follicular lymphomas in PTEN/LKB1-deficient mice

Background:

The PI3K–mTOR (phosphoinositide 3-kinase–mammalian target of rapamycin kinase) pathway is activated in the majority of tumours, and there is interest in assessing whether inhibitors of PI3K or mTOR kinase have efficacy in treating cancer. Here, we define the effectiveness of specific mTOR (AZD8055) and PI3K (GDC-0941) inhibitors, currently in clinical trials, in treating spontaneous B-cell follicular lymphoma that develops in PTEN^+/−LKB1^+/hypo mice.

Methods:

The PTEN^+/−LKB1^+/hypo mice were administered AZD8055 or GDC-0941, and the volumes of B-cell follicular lymphoma were measured by MRI. Tumour samples were analysed by immunohistochemistry, immunoblot and flow cytometry.

Results:

The AZD8055 or GDC-0941 induced ∼40% reduction in tumour volume within 2 weeks, accompanied by ablation of phosphorylation of AKT, S6K and SGK (serum and glucocorticoid protein kinase) protein kinases. The drugs reduced tumour cell proliferation, promoted apoptosis and suppressed centroblast population. The AZD8055 or GDC-0941 treatment beyond 3 weeks caused a moderate additional decrease in tumour volume, reaching ∼50% of the initial volume after 6 weeks of treatment. Tumours grew back at an increased rate and displayed similar high grade and diffuse morphology as the control untreated tumours upon cessation of drug treatment.

Conclusion:

These results define the effects that newly designed and specific mTOR and PI3K inhibitors have on a spontaneous tumour model, which may be more representative than xenograft models frequently employed to assess effectiveness of kinase inhibitors. Our data suggest that mTOR and PI3K inhibitors would benefit treatment of cancers in which the PI3K pathway is inappropriately activated; however, when administered alone, may not cause complete regression of such tumours.

MDX-070, a human anti-plasma antibody, administered as either a single dose or as multiple doses to patients with hormone-refractory prostate cancer

14549

Background: Prostate-specific membrane antigen (PSMA) is a type II transmembrane glycoprotein that is specifically expressed in prostatic epithelial cells and up-regulated in hormone refractory prostate cancer (HRPC). MDX-070 is a HuMAb that recognizes conformational epitopes on PSMA, mediates anti-body-dependent cellular cytotoxicity (ADCC), and is internalized. The primary objective of these studies was to establish the safety and tolerability and maximum tolerated dose (MTD) of MDX070 in patients (pts) with HRPC. Secondary objectives included characterization of the pharmacokinetic (PK) profile and a preliminary assessment of clinical antitumor activity measured by PSA levels and scans. Methods: MDX070 was administered intravenously over 90 minutes to pts with HRPC as either a single dose (Protocol MDX070–01) at dose levels of 0.1 (3 pts), 0.5 (3 pts), 1 (3 pts), 5 (3 pts), or 10 (6 pts) mg/kg/dose or every two weeks for up to 4 doses (Protocol MDX070–02) at dose levels of 1 (9 pts), 5 (6 pts), and 10 (15 pts) mg/kg/dose. Pts with stable disease or better at the end of the treatment period could receive additional treatment cycles until progression in a companion protocol (MDX070–03). Results: There were no Grade 4 toxicities judged to be related to MDX070 administration. One patient experienced Grade 3 anorexia that was possibly drug-related (5 mg/kg). Grade 1 or 2 toxicities (reported in 35 pts in the clinical database- 18 in 01, and 17 in 02) deemed to be related to MDX070 included anorexia (2), fatigue (3), fever (4), nausea (3) and vomiting (2). No significant differences in toxicity were seen between dose groups. No >50% decline in PSA or response according to RECIST criteria occurred in any of the dosing cohorts, but 6 patients had stable disease and received 1 or more additional cycles of treatment at the same dose. Conclusions: MDX-070 as monotherapy, at the dose levels administered, was safe and well tolerated. No objective antitumor activity was observed at the dose levels tested, however, 20% (6/30) had stable disease. Enrollment is continuing at the 10 mg/kg multi-dose cohort. PK analysis is ongoing.

[Table: see text]

Phase I study of the effects of hepatic impairment on the pharmacokinetic (PK) and safety of satraplatin in patients with refractory non-hematologic cancer

2045

Background: Satraplatin (S) is a third-generation oral platinum analog that has demonstrated activity in the treatment of patients with platinum-sensitive malignancies. A worldwide double-blind, placebo controlled randomized phase III trial evaluating S as 2nd line therapy for HRPC has recently completed enrollment. The current study was designed to determine the effect of hepatic impairment on S pharmacokinetics in patients with refractory cancer, as well as treatment efficacy and toxicity. Methods: S was administered orally at a dose of 80mg/m2/day (d) on d1–5 every 35 days. Study groups (cohorts) were defined at 4 levels of hepatic impairment - Group 1 (G1) = control; G2 = Child-Pugh Class A; G3 = Child-Pugh Class B; and Group 4 = Child-Pugh Class C. Results: 19 pts have been enrolled to date (11 M/ 8 F); median age is 57 (range 44–80). Pts with prostate (2), pancreas (4), colorectal (3), adenocystic (2), and 1 each neuroendocrine, hepatocellular, melanoma, breast, ovarian, SCLC, and anal cancers were enrolled. 8 pts were in G1, 3 pts in G2, 4 pts in G3, and 5 pts in G4. Accrual is ongoing in this study with a total of 8 pts planned for each group. The median number of prior regimens was 5 (range 2–8). A total of 35 cycles of S have been given: median 2/pt (range 1–4). 9 pts have completed 2 cycles of S. Hematologic toxicities during the first 2 cycles included grade (G) 3/4 thrombocytopenia in 15 %. There were no cases of G 3/4 neutropenia or anemia. One case of G3 hypokalemia, was reported. Two patients developed acute renal failure; one of which was due to uncontrolled nausea (N) and vomiting (V) and the other was associated with rapid disease progression in the liver. Both were G4 patients. Otherwise, N, V, and diarrhea were mild to moderate, and controlled with oral therapy. Conclusions: S is, in general, well tolerated in patients with mild or moderate liver impairment. Severe thrombocytopenia is the most common side-effect. Of the patients enrolled to date 15% did not have progression of disease. PK data will also be presented.

[Table: see text]

Expression of p300-truncated fragments results in the modulation of apoptosis in rat mesangial cells

BACKGROUND

Mesangial cell proliferation, apoptosis, and matrix deposition have pivotal roles in the pathogenesis of renal diseases such as diabetic nephropathy and glomerulonephritis. The behavior of mesangial cells depends on the integration of intracellular signals elicited by hormones and cytokines. We hypothesized that p300 is primarily involved in the integration of signal transduction pathways in rat mesangial cells (RMCs) and that interference with p300 function will alter apoptotic signals.

METHODS

We established an RMC cell line expressing the Tet-activator (tTA). RMC-tTA cells were transiently transfected with vectors coding for either the N-terminal third or the C-terminal third of p300. Expression was induced by the addition of doxycycline [Dox; 1 microg/mL; 5% fetal bovine serum (FBS)]. The percentage of apoptosis was determined using the TUNEL technique. Specific protein-protein interactions were determined by Western blot analysis of immunoprecipitated complexes. Cells were treated with 5% FBS or with H2O2 (500 micromol/L, 1 h) with and without Dox.

RESULTS

The expression of p300-C resulted in increased susceptibility to low serum-induced (20.0 +/- 4.6 vs. 3.0 +/- 1.7%) and to H2O2-induced apoptosis (75.3 +/- 13.3 vs. 50.8 +/- 6.5%) compared with controls. Immunoprecipitation of p300-C showed an interaction with the transcription factor c-Fos, which was enhanced by H2O2 treatment. Expression of the p300-N resulted in a rescue (34.8 +/- 6. 4 vs. 50.8 +/- 6.5%) from H2O2-induced apoptosis compared with controls. P300-N was shown to form a complex with the transcription factor nuclear factor-kappaB (NF-kappaB).

CONCLUSIONS

The data indicate that endogenous p300 is involved in apoptosis in mesangial cells. We propose that interference or enhancement of endogenous p300 function, by expression of exogenous fragments, can alter interactions with c-Fos or NF-kappaB and modulate signals during cellular stress.

Australia's notifiable diseases status, 1998. Annual report of the National Notifiable Diseases Surveillance System

In 1998 there were 85,096 notifications to the National Notifiable Diseases Surveillance System; slightly lower than in 1997 (89,579). The number of measles cases remained low, and well below the number reported in the outbreak years of 1993 and 1994. Rubella notifications further decreased and remained low in 1998. The Measles Control Campaign from August to November 1998, did not impact significantly on the number of measles or rubella cases reported for 1998. Notifications of Haemophilus influenzae type b reached a record low since surveillance began in 1991, and appeared to have stabilised at a low rate since the introduction of the conjugated vaccine in 1992. The previously reported outbreak of pertussis in 1997 tapered off in early 1998. Food-borne disease, or detection of disease, appeared to be on the rise with an increase in notification rates of campylobacteriosis and salmonellosis. Notifications of hepatitis A decreased, correcting the previous high number of notifications in 1997. Sexually transmissible diseases (STDs) increased. Notifications for chlamydial infection were the highest for all sexually transmitted diseases and third highest for all notifiable diseases. Notifications of gonococcal infection also continued to rise and have doubled since 1991, whilst notifications for syphilis increased slightly after falling steadily over recent years. Arbovirus infections of concern in 1998 were dengue outbreaks in Far North Queensland and the first case of Japanese Encephalitis for mainland Australia, highlighting the importance of surveillance of arboviruses and vectors for their detection and management.

The Pseudomonas syringae pv. tomato HrpW protein has domains similar to harpins and pectate lyases and can elicit the plant hypersensitive response and bind to pectate

The host-specific plant pathogen Pseudomonas syringae elicits the hypersensitive response (HR) in nonhost plants and secretes the HrpZ harpin in culture via the Hrp (type III) secretion system. Previous genetic evidence suggested the existence of another harpin gene in the P. syringae genome. hrpW was found in a region adjacent to the hrp cluster in P. syringae pv. tomato DC3000. hrpW encodes a 42. 9-kDa protein with domains resembling harpins and pectate lyases (Pels), respectively. HrpW has key properties of harpins. It is heat stable and glycine rich, lacks cysteine, is secreted by the Hrp system, and is able to elicit the HR when infiltrated into tobacco leaf tissue. The harpin domain (amino acids 1 to 186) has six glycine-rich repeats of a repeated sequence found in HrpZ, and a purified HrpW harpin domain fragment possessed HR elicitor activity. In contrast, the HrpW Pel domain (amino acids 187 to 425) is similar to Pels from Nectria haematococca, Erwinia carotovora, Erwinia chrysanthemi, and Bacillus subtilis, and a purified Pel domain fragment did not elicit the HR. Neither this fragment nor the full-length HrpW showed Pel activity in A230 assays under a variety of reaction conditions, but the Pel fragment bound to calcium pectate, a major constituent of the plant cell wall. The DNA sequence of the P. syringae pv. syringae B728a hrpW was also determined. The Pel domains of the two predicted HrpW proteins were 85% identical, whereas the harpin domains were only 53% identical. Sequences hybridizing at high stringency with the P. syringae pv. tomato hrpW were found in other P. syringae pathovars, Pseudomonas viridiflava, Ralstonia (Pseudomonas) solanacearum, and Xanthomonas campestris. DeltahrpZ::nptII or hrpW::OmegaSpr P. syringae pv. tomato mutants were little reduced in HR elicitation activity in tobacco, whereas this activity was significantly reduced in a hrpZ hrpW double mutant. These features of hrpW and its product suggest that P. syringae produces multiple harpins and that the target of these proteins is in the plant cell wall.

Characterization of the hrpC and hrpRS operons of Pseudomonas syringae pathovars syringae, tomato, and glycinea and analysis of the ability of hrpF, hrpG, hrcC, hrpT, and hrpV mutants to elicit the hypersensitive response and disease in plants

The species Pseudomonas syringae encompasses plant pathogens with differing host specificities and corresponding pathovar designations. P. syringae requires the Hrp (type III protein secretion) system, encoded by a 25-kb cluster of hrp and hrc genes, in order to elicit the hypersensitive response (HR) in nonhosts or to be pathogenic in hosts. DNA sequence analysis of the hrpC and hrpRS operons of P. syringae pv. syringae 61 (brown spot of beans), P. syringae pv. glycinea U1 (bacterial blight of soybeans), and P. syringae pv. tomato DC3000 (bacterial speck of tomatos) revealed that the 13 genes comprising the right half of the hrp cluster (including those in the previously sequenced hrpZ operon) are conserved and identically arranged. The hrpC operon is comprised of hrpF, hrpG, hrcC, hrpT, and hrpV. hrcC encodes a putative outer membrane protein that is conserved in all type III secretion systems. The other four genes appear to be characteristic of group I Hrp systems, such as those possessed by P. syringae and Erwinia amylovora. The predicted products of these four genes in P. syringae pv. syringae 61 are HrpF (8 kDa), HrpG (15.4 kDa), HrpT (7.5 kDa), and HrpV (13.4 kDa). HrpT is a putative outer membrane lipoprotein. HrpF, HrpG, and HrpV are all hydrophilic proteins lacking N-terminal signal peptides. The HrpG, HrcC, HrpT, and HrpV proteins of P. syringae pathovars syringae and tomato (the two most divergent pathovars) had at least 76% amino acid identity with each other, whereas the HrpF proteins of these two pathovars had only 36% amino acid identity. The HrpF proteins of P. syringae pathovars syringae and glycinea also showed significant similarity to the HrpA pilin protein of P. syringae pathovar tomato. Functionally nonpolar mutations were introduced into each of the genes in the hrpC operon of P. syringae pv. syringae 61 by insertion of an nptII cartridge lacking a transcription terminator. The mutants were assayed for their ability to elicit the HR in nonhost tobacco leaves or to multiply and cause disease in host bean leaves. Mutations in hrpF, hrcC, and hrpT abolished or greatly reduced the ability of P. syringae pv. syringae 61 to elicit the HR in tobacco. The hrpG mutant had only weakly reduced HR activity, and the activity of the hrpV mutant was indistinguishable from that of the wild type. Each of the mutations could be complemented, but surprisingly, the hrpV subclone caused a reduction in the HR elicitation ability of the DeltahrpV::nptII mutant. The hrpF and hrcC mutants caused no disease in beans, whereas the hrpG, hrpT, and hrpV mutants had reduced virulence. Similarly, the hrcC mutant grew little in beans, whereas the other mutants grew to intermediate levels in comparison with the wild type. These results indicate that HrpC and HrpF have essential functions in the Hrp system, that HrpG and HrpT contribute quantitatively but are not essential, and that HrpV is a candidate negative regulator of the Hrp system.

Negative regulation of hrp genes in Pseudomonas syringae by HrpV

Mutations in the five hrp and hrc genes in the hrpC operon of the phytopathogen Pseudomonas syringae pv. syringae 61 have different effects on bacterial interactions with host and nonhost plants. The hrcC gene within the hrpC operon encodes an outer membrane component of the Hrp secretion system that is conserved in all type III protein secretion systems and is required for most pathogenic phenotypes and for secretion of the HrpZ harpin to the bacterial milieu. The other four genes (in order), hrpF, hrpG, (hrcC), hrpT, and hrpV, appear to be unique to the group I hrp clusters found in certain phytopathogens (e.g., P. syringae and Erwinia amylovora) and are less well understood. We initiated an examination of their role in Hrp regulation and secretion by determining the effects of functionally nonpolar nptII cartridge insertions in each gene on the production and secretion of HrpZ, as determined by immunoblot analysis of cell fractions. P. syringae pv. syringae 61 hrpF, hrpG, and hrpT mutants were unable to secrete HrpZ, whereas the hrpV mutant overproduced and secreted the protein. This suggested that HrpV is a negative regulator of HrpZ production. Further immunoblot assays showed that the hrpV mutant produced higher levels of proteins encoded by all three of the major hrp operons tested-HrcJ (hrpZ operon), HrcC (hrpC operon), and HrcQB (hrpU operon)-and that constitutive expression of hrpV in trans abolished the production of each of these proteins. To determine the hierarchy of HrpV regulation in the P. syringae pv. syringae 61 positive regulatory cascade, which is composed of HrpRS (proteins homologous with sigma54-dependent promoter-enhancer-binding proteins) and HrpL (alternate sigma factor), we tested the ability of constitutively expressed hrpV to repress the activation of HrcJ production that normally accompanies constitutive expression of hrpL or hrpRS. No repression was observed, indicating that HrpV acts upstream of HrpRS in the cascade. The effect of HrpV levels on transcription of the hrpZ operon was determined by monitoring the levels of beta-glucuronidase produced by a hrpA'::uidA transcriptional fusion plasmid in different P. syringae pv. syringae 61 strains. The hrpV mutant produced higher levels of beta-glucuronidase than the wild type, a hrcU (type III secretion) mutant produced the same level as the wild type, and the strain constitutively expressing hrpV in trans produced low levels equivalent to that of a hrpS mutant. These results suggest that HrpF, HrpG, and HrpT are all components of the type III protein secretion system whereas HrpV is a negative regulator of transcription of the Hrp regulon.

Inhibition of cell proliferation and induction of apoptosis by the retinoid AHPN in human lung carcinoma cells

In this study, we investigated the effect of the novel retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (AHPN/CD437) on the growth of human lung carcinoma cell lines. AHPN inhibits the proliferation of all cell lines tested, irrespective of the lung tumor type, in a concentration- and time-dependent manner. A dramatic reduction in cell number was observed in adenocarcinoma H460 cells, and was shown to be related to an induction of apoptosis. Bromodeoxyuridine (BrdU) incorporation and flow-cytometric analyses indicated that treatment of H460 cells with AHPN induces cell-cycle arrest at the G1 phase. We therefore investigated the effect of AHPN on several regulatory proteins of the G1 phase of the cell-cycle. The cell-cycle arrest induced by AHPN was accompanied by an inhibition of the hyperphosphorylation of the retinoblastoma (Rb) protein, an indication of G1 arrest. Furthermore, two cyclin-dependent kinases, cdk2 and cdk4, which are normally involved in the phosphorylation of Rb, were shown to have decreased activity. In some cell lines, the decrease in cdk activity may be partly related to an increase in p21(WAF1/Cip1) (p21), an inhibitor of cyclin-dependent kinases. No changes were observed in the cyclin-dependent kinase inhibitor p27(Kip1). The observed increase in p53 in response to AHPN could at least to some extent be responsible for the increased levels of p21. The increase in p53 expression was found to be regulated at a post-transcriptional level. Our results suggest that the growth inhibition of certain lung carcinoma cell lines by AHPN is at least partly related to an increase in p21. However, in other cell lines, different mechanisms appear to be involved. The specificity with which AHPN and other retinoids induce growth arrest and p21 expression indicates that the action of AHPN is not mediated by RAR or RXR receptors, but involves a novel signaling pathway.

The HrpZ proteins of Pseudomonas syringae pvs. syringae, glycinea, and tomato are encoded by an operon containing Yersinia ysc homologs and elicit the hypersensitive response in tomato but not soybean

The Pseudomonas syringae pathovars are composed of host-specific plant pathogens that characteristically elicit the defense-associated hypersensitive response (HR) in nonhost plants. P. s. pv. syringae 61 secretes an HR elicitor, harpinPss (HrpZPss), in a hrp-dependent manner. An internal fragment of the P. s. pv. syringae 61 hrpZ gene was used to clone the hrpZ locus from P. s. pv. glycinea race 4 (bacterial blight of soybean) and P. s. pv. tomato DC3000 (bacterial speck of tomato). DNA sequence analysis revealed that hrpZ is the second ORF in a polycistronic operon. The amino acid sequence identities of HrpZPss/HrpZPsg and HrpZPss/HrpZPst were 79 and 63%, respectively. Although none of the HrpZ proteins showed significant overall sequence similarity with other known proteins, HrpZPst contained a 24-amino acid sequence that is homologous with a region of the PopA1 elicitor protein of the tomato pathogen, Pseudomonas solanacearum GMI1000. hrpA, the upstream ORF, was highly divergent: The amino acid sequence identities of HrpAPss/HrpAPsg and HrpAPss/HrpAPst were 91 and 28%, respectively, and no HrpA sequence showed similarity to known proteins. In contrast, the predicted products of the downstream ORFs in P. s. pv. syringae and P. s. pv. tomato, hrpB, hrpC, hrpD, and hrpE showed varying levels of similarity to those of yscI, yscJ, yscK, and yscL. These are colinearly arranged genes in the virC locus of Yersinia spp., which are involved in the secretion of the Yop virulence proteins via the type III pathway. The similarity of the Ysc proteins was generally stronger in comparisons with the P. s. pv. tomato Hrp proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Jugular bulb catheterization does not increase intracranial pressure

Cerebral venous monitoring through jugular bulb catheterization (JBC) allows assessment of global oxygen delivery adequacy. Because of concern that venous obstruction by catheterization may cause or exacerbate intracranial hypertension, physicians are reluctant to puncture this vessel in brain-injured patients. We evaluated the impact of JBC on intracranial pressure (ICP). 37 consecutive pediatric patients with jugular bulb catheters and ICP monitoring were studied. ICP was monitored in 28 patients during JBC. Also immediately after JBC and daily thereafter the contralateral, ipsilateral, and bilateral jugular veins were compressed in all 37 patients to assess patency of these vessels. Change in ICP was noted. If ICP increased more than 5 torr, compression was stopped. Preinsertion ICP was 17.3 +/- 5.1 and postinsertion 17.2 +/- 5.1 torr. The maximum rise in ICP was 2 torr in a single patient while 6 others had a decrease in ICP. 120 compression tests were performed. Compression ipsilateral to the catheter caused the ICP to rise from 16.0 +/- 4.3 to 18.4 +/- 4.4 torr, and in contralateral compression 15.9 +/- 4.2 to 17.0 +/- 4.4. Neither the duration of catheterization nor the precompression ICP correlated with the rise in ICP. These data revealed no evidence of jugular venous obstruction in the catheterized vessel. We conclude that JBC can be performed in patients without aggravating an elevated ICP.

Jugular bulb catheterization: experience with 123 patients

Jugular bulb catheterization (JBC) provides cerebral venous access for titration of brain-specific therapy. Little has been written about the catheterization procedure. We prospectively studied the time, number of punctures, success rate, and complications during JBC for a 24-month period in our ICUs. One hundred twenty-three patients (mean age 6.7 yr, range 12 hours to 21 yr) underwent JBC. Procedure time was 15.6 +/- 5.0 (SD) min. Median number of skin punctures was two. All but four were successful on first attempt. Three of the remaining were catheterized on second attempt. Inadvertent carotid puncture occurred in 3%. No other significant complications were noted. Radiography confirmed proper position in 97%. Duration of indwelling venous catheters was 2.5 +/- 1.6 days. All catheters functioned well until removal. We conclude that our technique of JBC is safe and highly successful. It compares favorably with previous, smaller series and with standard anterograde internal jugular catheterization in both children and adults.

Acute pulmonary edema after near strangulation

We report a case of acute, noncardiogenic pulmonary edema in an 11-year-old boy who suffered strangulation during an altercation. The clinical presentation was characterized by moderate respiratory distress and hemoptysis. Both the radiographic and clinical findings resolved during the three day admission which followed. A review of the literature is presented, and possible pathogenesis is discussed.

Reye syndrome and juvenile rheumatoid arthritis in Michigan

Reye syndrome (RS) is believed to occur infrequently among children receiving long-term aspirin therapy. We reviewed all cases of RS reported to the Michigan Department of Public Health during 1982 and 1983. Three of the 36 patients were receiving aspirin for the treatment of juvenile rheumatoid arthritis. All three patients had clinical courses characteristic of RS and two had supportive histologic findings on liver biopsy. The incidence of RS among children with juvenile rheumatoid arthritis is significantly greater than the incidence of RS among children who do not have juvenile rheumatoid arthritis. These findings support previous studies that showed that the use of aspirin during the antecedent illness may be a risk factor for the development of RS. Physicians should be aware of the potential for the development of RS among children who are receiving long-term aspirin therapy for the treatment of systemic inflammatory illnesses.

Intracranial pressure and cerebral perfusion pressure in near-drowning

Intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were strictly controlled in 11 pediatric victims of near-drowning. Three outcome groups were defined: complete recovery, persistent vegetative state, and death. In the early postimmersion phase (first 72 h), CPP was consistently above 50 mm Hg in all patients. There were occasional, nonrepetitive, and easily controllable ICP spikes above 15 mm Hg in three patients from each group. Repeated ICP spikes above 15 mm Hg were observed in some patients with adverse outcome only after 72 h. Successful control of ICP and CPP did not ensure intact survival, and sustained late intracranial hypertension is more likely a sign of profound neurologic insult rather than its cause.

Effects of anoxia on cerebral blood flow in the rat brain: evidence for a role of adenosine in autoregulation

The purpose of these experiments was to determine the utility of a new method for monitoring CBF using a venous outflow technique with an extracorporeal circulation and to examine the effects of agents that potentiate or antagonize the actions of adenosine on the blood flow response to brief periods of anoxia. The results demonstrate the ability of the new technique to detect the increases in CBF in response to anoxia. Caffeine, an adenosine antagonist, reduced the intensity and duration of the anoxia-induced hyperemia. Dipyridamole and papaverine, inhibitors of adenosine uptake, potentiated the increase in CBF during anoxia. The results support the hypothesis that adenosine plays an important role in regulating CBF during anoxic episodes.

Transient intellectual and psychosocial regression during recovery phase of stage V Reye's syndrome

The outcome of stage V Reye's syndrome survivors has not been critically assessed. Three teenage survivors, who initially exhibited severe psychosocial and intellectual regression, are described. Findings support the observation that the neurological outcome from Reye's syndrome correlates with the duration of altered consciousness during the acute phase. Recovery of intellectual, psychosocial, learning and motor function is reported. A period of transient dementia was noted, which may be typical in recovery from stage V Reye's syndrome. Unlike other types of encephalopathies, complete resolution may be expected.