Further evidence for the decay K+ -->pi+nu(nu)

Additional evidence for the rare kaon decay K+-->pi+nu(nu) has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, 211<P<229 MeV/c, bringing the total for the combined data set to two. Including all data taken, the backgrounds were estimated to contribute 0.15+/-0.05 events. The branching ratio is B(K+-->pi+nu(nu)) = 1.57(+1.75)(-0.82)x10(-10).

Multi-centre assessment of the Spiegelberg compliance monitor: preliminary results

Acute brain injury states (e.g. head injury, subarachnoid haemorrhage) show clear inverse relationships of ICP vs compliance, with ICP instability at times of lower compliance states. Variance in compliance values is large in hydrocephalus where ICP is relatively lower and compliance higher. Nonetheless, early experience shows that compliance data influence decisions on CSF diversion treatments. Future work will focus on the ability of intracranial compliance to predict ensuing ICP instability and methodological refinement for monitoring patients who have higher compliance states.

Auto-catalyzed poly(ortho ester) microspheres: a study of their erosion and drug release mechanism

A study has been carried out to investigate the degradation and protein release mechanisms of BSA-loaded microspheres made with auto-catalyzed poly(ortho esters) (POEs) of varying diol composition and molecular weights. Due to the instability of the POE/dichloromethane primary emulsion, microspheres made using the W/O/W double emulsion solvent extraction/evaporation method showed a multivesicular internal structure. An O/W single emulsion process yielded dense POE microspheres. Using electron scanning microscopy, the microspheres were observed to erode throughout their matrices with increasing internal pore sizes and a steady loss of mass. However, despite a substantial weight loss of almost 80% after an in vitro period of 129 days, the molecular weight of the polymer remained relatively unchanged with loss averaging about 18 and 32% for low- and high-molecular-weight POEs, respectively. Such constancy in molecular weight was similarly reflected in the glass transition temperature of the degrading microspheres. The differences in both the molecular weight loss and polydispersity index changes depended largely on the molecular weight of the polymer. For protein release of POE microspheres, an induction period followed by BSA release for a period of 3 to 10 days was observed. The lag time depended on the hydrophilicity and the molecular weight of the polymer as well as the morphology of the microspheres. Protein release was incomplete, possibly due to the slow degradation of the POE polymers, protein aggregation and protein degradation.

POE-PEG-POE triblock copolymeric microspheres containing protein. I. Preparation and characterization

Poly(ortho ester) (POE)-poly (ethylene glycol) (PEG) triblock copolymers (POE-PEG-POE) with different PEG contents were synthesised as carriers for controlled protein delivery. POE-PEG-POE microspheres containing bovine serum albumin (BSA) were prepared using a double-emulsion (water-in-oil-in-water) process. In this first paper of a two-part series, we report the fundamentals of the fabrication and characterization of POE-PEG-POE microspheres. Because the triblock copolymer is more hydrophilic than neat poly(ortho ester), the triblock copolymer yields a more stable first emulsion (water-in-oil) and a greater BSA encapsulation efficiency (90% vs. 30%). No BSA is found on POE-PEG-POE microsphere surfaces measured by X-ray photoelectron spectroscopy, while uniform BSA distributions are observed within the microspheres by confocal microscopy. SEM pictures show that an increase in PEG content results in microspheres with a denser cross-section because of a more stable first emulsion and better affinity between the copolymer and water. POE-PEG(20%)-POE suffers significant swelling during the fabrication process and yields the biggest microspheres. However, the POE-PEG(30%)-POE microspheres are much smaller since the dissolution loss of POE-PEG(30%)-POE in the external water phase may be much higher than that of POE-PEG(20%)-POE. The salt concentration in the external water phase significantly affects the morphology of the resultant microspheres. Microspheres with a dense wall are produced when using pure water as the external water phase. Polymer concentration has less impact on BSA encapsulation efficiency but has a considerable effect on microsphere size and morphology. Increasing the concentration of the polyvinyl alcohol emulsifier does not cause an obvious decrease in microsphere size. However, increased BSA loading results in bigger microspheres.

POE-PEG-POE triblock copolymeric microspheres containing protein. II. Polymer erosion and protein release mechanism

The first paper of this series presented the fabrication and characterization of POE-PEG-POE triblock copolymeric microspheres containing protein. In this paper, we focus on the polymer erosion and the mechanism of protein release. Fourteen-week in vitro behaviors of POE-PEG-POE microspheres loaded with bovine serum albumin (BSA) have been monitored. SEM micrographs reveal that after 14-week incubation in PBS buffer, pH 7.4, 37 degrees C, the polymeric particles remain spherical despite mass loss of almost 90%. On the other hand, molecular weight undergoes a high initial loss of 38% and 44% during the first 2-week incubation for POE-PEG(5%)-POE and POE-PEG(10%)-POE, respectively. Then, it keeps relatively unchanged over 12 weeks. However, POE-PEG(20%)-POE copolymer provides a better compatibility between the POE and PEG blocks. Hydrolysis is homogeneous through the polymer backbone. Thus, its molecular weight remains relatively constant and mass loss shows quite sustained over the 14-week in vitro release. The similar phenomena are observed in the polydispersity index of the degrading copolymers. SDS-PAGE of the encapsulated BSA within the POE-PEG(5%)-POE microspheres displays that the structural integrity of BSA is intact for at least 8 weeks due to a mild environment provided by the copolymer. In addition, XPS and FTIR are utilized to investigate protein behaviors in the degrading microspheres. Protein release from the POE-PEG-POE microspheres shows a biphasic pattern, characterized by an initial stage followed by a non-detectable release. The non-release phase is dominated by either slow polymer degradation or dense microsphere matrix structures. The microsphere formulation is optimized and a sustained protein release over 2 weeks is achieved by using POE-PEG(20%)-POE at a high protein loading.

High-dose methotrexate for primary CNS lymphoma in the elderly

Primary central nervous system lymphoma (PCNSL) in the immunocompetent patient reaches a peak incidence in the sixth and seventh decades of life. This retrospective study reviewed the efficacy and tolerability of high-dose methotrexate (HDMTX) in an elderly patient population. Between May 1995 and September 1998, ten consecutive elderly patients with histologically proven PCNSL were treated with HDMTX. The median age was 72.5 years and eight patients (80%) were older than 70 years. HDMTX was well tolerated with no episodes of grade 4 toxicity nor febrile neutropenia. Toxicity included grade 3 nausea (1), grade 2 mucositis (2), and grade 2 asymptomatic elevation of liver transaminases (2). Grade 1 toxicity occurred in three patients with nausea, diarrhea, and mild reversible elevation in serum creatinine in one patient each. Six patients had a complete response and three patients achieved a partial response, giving an overall response rate of 90% (95% confidence interval, 56%-100%). The median overall survival for the cohort was 36 months (range 4-43 months). In summary, HDMTX is well tolerated in this elderly population with PCNSL and achieves response rates and median survival comparable with other chemotherapy or radiotherapy regimens.

The maximal Hughes procedure

PURPOSE

To describe the use of oblique medial and lateral periosteal flaps with the Hughes tarsoconjunctival flap for the repair of maximal defects of the lower eyelid.

METHODS

A small prospective case series of eight patients requiring lower eyelid reconstruction following with maximal defect of the lower eyelid. The patients underwent a Hughes tarsoconjunctival advancement combined with oblique medial and lateral periosteal flaps, and were assessed for aesthetic outcome and surgical complications.

RESULTS

All patients had uncomplicated surgery. Outcomes assessed included corneal protection, eye closure, lower eyelid retraction, complications, and patient satisfaction. Eyelid contour and protection was excellent in all patients. Postoperatively, one patient had mild lower eyelid retraction, and in a second patient, medial ectropion with mild lower eyelid retraction developed that required subsequent revision.

CONCLUSIONS

The maximal Hughes procedure is a safe and effective procedure that may be performed with patients under local anesthesia and may avoid the need for more extensive techniques for surgical repair of maximal defects of the lower eyelid.

Necrotizing enterocolitis in the full-term neonate

Necrotizing enterocolitis (NEC) is a relatively common disorder of multifactorial aetiology that primarily affects preterm newborns, but has been reported to occur in the full-term neonate as well. This review focuses on known and recent developments in the epidemiology, pathogenesis, diagnosis, management and prevention of NEC in the full-term neonate.

Low-binding alleles of Fcgamma receptor types IIA and IIIA are inherited independently and are associated with systemic lupus erythematosus in Hispanic patients

OBJECTIVE

To examine the relationship between allelic polymorphisms of IgG receptors (FcgammaR) and the development of lupus nephritis in a prospective study, and to determine the distribution of FcgammaR haplotypes (FcgammaRIIA and FcgammaRIIIA genotypes) in lupus patients and disease-free control subjects.

METHODS

We studied 67 Hispanic systemic lupus erythematosus (SLE) patients from a prospective study of outcome and 53 disease-free control subjects. Patients were followed up longitudinally for 3 years. FcgammaRIIA and FcgammaRIIIA genotypes were determined using allele-specific polymerase chain reaction.

RESULTS

Nephritis was present in 28% of patients at entry into the study and in 69% at the end of 3 years. In the nephritis group (n = 46), as well as the entire SLE cohort, there was a predominance of genotypes with low-binding alleles (FcgammaRIIa-R131 and FcgammaRIIIa-F176) at both loci (SLE nephritis patients 89% versus controls 62%; P < 0.002; odds ratio 0.20 [95% confidence interval 0.05-0.6] for risk of nephritis in individuals homozygous for either FcgammaRIIa-H131 or FcgammaRIIIaV176). The frequency of individuals homozygous for high-binding alleles at either locus decreased as the burden of disease increased (P < 0.002, by Mann-Whitney test). There was no linkage disequilibrium between FcgammaRIIA and FcgammaRIIIA in Hispanics, yet in the SLE patients, there was a clear overrepresentation of the FcgammaRIIa-R131;FcgammaRIIIa-F176 haplotype (SLE patients 48% versus controls 30%) and a decrease in the frequency of the high-binding haplotype (4% versus 23%) (P < 0.002).

CONCLUSION

We observed an increase in the frequency of low-binding FcgammaR alleles in an SLE population with a high prevalence of renal disease. The apparent selection for the FcgammaRIIa-R131;FcgammaRIIIa-F176 haplotype in Hispanic patients suggests that low-binding alleles of both FcgammaRIIa and FcgammaRIIIa confer risk for SLE and may act additively in the pathogenesis of disease, whereas the high-binding haplotype FcgammaRIIa-H131;FcgammaRIIIa-V176 is protective, particularly in the homozygous state.

Primate mammary gland insulin-like growth factor system: cellular localization and regulation by sex steroids

BACKGROUND

Insulin-like growth factor 1 (IGF1) plays a critical role in estrogen-induced uterine proliferation, but it is unclear whether this estromedin function occurs in other estrogen-sensitive tissues such as the mammary gland. To elucidate this possibility, we investigated the cellular localization and hormonal regulation of mRNAs for IGF1 and 2, their cognate receptors (IGF1R, IGF2R), and IGF binding proteins 2-5 (BPs 2-5) in the rhesus monkey mammary gland.

METHODS

Ovariectomized monkeys were treated with placebo, estradiol (E2), and E2 plus progesterone (E2/P4) for 3 days, after which mammary tissue was harvested for in situ hybridization and immunohistochemical analyses.

RESULTS

IGF1 and IGF2 mRNA levels were significantly increased and BP2 mRNA decreased by E2 and by E2/P4 treatment. IGF1R mRNA was increased by combined E2/P treatment but not by E2 alone. BP5 mRNA was decreased by E2/P4. No differences in IGF2R, BP3, and BP4 mRNA levels were detected in any treatment group. Mammary IGF1 and IGF2 mRNA levels were both positively correlated with local epithelial proliferation, assessed by immunodetection of the proliferation-specific antigen, Ki67.IGF1 and IGF1R expression were negatively correlated with local programmed cell death, as assessed by the in situ TUNEL method. In contrast, BP2 expression was negatively correlated with epithelial proliferation and positively correlated with programmed cell death. IGF2R, BP3, BP4, and BP5 levels were not significantly correlated with either proliferation or death.

CONCLUSIONS

Thus, E2-induced proliferation is associated with upregulation of both IGF1 and IGF2 expression and downregulation of BP2 expression. These data suggest that the local mammary IGF system is involved in sex steroid-induced mammary epithelial cell hyperplasia.

Investigating Murray's law in the chick embryo

According to the optimization principle known as Murray's law, the blood vessel geometry at a bifurcation satisfies the relation alpha = (D3(1) + D3(2))/D3(0) = 1, where D0, D1, and D2 are the diameters of the parent and two daughter vessels, respectively. Previous investigations have shown that mature blood vessels adhere to this law fairly closely. The purpose of this study was to test Murray's law in the developing extraembryonic blood vessels of 2-4 day-old chick embryos. Vessel diameters were measured manually using image analysis software. The measurements for the group of all vessels at all studied stages (n = 449) gave alpha = 1.01+/-0.34 (mean +/- SD), and the value of alpha is similar at all stages. These results indicate that Murray's law holds in the chick embryo, even before medial smooth muscle becomes functional, suggesting that blood vessels follow the same basic morphogenetic rules throughout life.

Circumdatin G, a new alkaloid from the fungus Aspergillus ochraceus

The crude extract of the broth of Aspergillus ochraceus was found to inhibit the final stage of polyprotein processing during hepatitis C virus replication. Bioassay-guided fractionation led to the isolation of the known compound mellein as the active component of the extract. Also isolated were circumdatin F and a new alkaloid, circumdatin G. The structure of circumdatin G was determined by spectroscopic analysis.

Discovery, purification, and characterization of a temperate transducing bacteriophage for Bordetella avium

We discovered and characterized a temperate transducing bacteriophage (Ba1) for the avian respiratory pathogen Bordetella avium. Ba1 was initially identified along with one other phage (Ba2) following screening of four strains of B. avium for lysogeny. Of the two phage, only Ba1 showed the ability to transduce via an allelic replacement mechanism and was studied further. With regard to host range, Ba1 grew on six of nine clinical isolates of B. avium but failed to grow on any tested strains of Bordetella bronchiseptica, Bordetella hinzii, Bordetella pertussis, or Bordetella parapertussis. Ba1 was purified by CsCl gradient centrifugation and was found to have an icosahedral head that contained a linear genome of approximately 46.5 kb (contour length) of double-stranded DNA and a contractile, sheathed tail. Ba1 readily lysogenized our laboratory B. avium strain (197N), and the prophage state was stable for at least 25 generations in the absence of external infection. DNA hybridization studies indicated the prophage was integrated at a preferred site on both the host and phage replicons. Ba1 transduced five distinctly different insertion mutations, suggesting that transduction was generalized. Transduction frequencies ranged from approximately 2 x 10(-7) to 1 x 10(-8) transductants/PFU depending upon the marker being transduced. UV irradiation of transducing lysates markedly improved transduction frequency and reduced the number of transductants that were lysogenized during the transduction process. Ba1 may prove to be a useful genetic tool for studying B. avium virulence factors.

An outbreak of ciguatera fish poisoning in Victoria

An outbreak of ciguatera fish poisoning in outer Melbourne in September 1997 was traced to a 16.2 kg Maori Wrasse fish imported into Victoria from Trunk Reef in Queensland. The outbreak involved 46 individuals attending a banquet at an Asian restaurant at which four different dishes prepared from the flesh and viscera of the fish were offered. In all 30 individuals consumed at least one of these dishes and all reported one or more symptoms, in the main gastrointestinal and/or in 18 cases neurological. Seventeen cases were seen in four different hospitals and nine were treated with parenteral mannitol therapy. Nine of 18 cases were still symptomatic 10 weeks after the episode. Education of Asian restaurateurs and the wider community about the risks of ciguatera fish poisoning was undertaken.

Testosterone inhibits estrogen-induced mammary epithelial proliferation and suppresses estrogen receptor expression

This study investigated the effect of sex steroids and tamoxifen on primate mammary epithelial proliferation and steroid receptor gene expression. Ovariectomized rhesus monkeys were treated with placebo, 17beta estradiol (E2) alone or in combination with progesterone (E2/P) or testosterone (E2/T), or tamoxifen for 3 days. E2 alone increased mammary epithelial proliferation by approximately sixfold (P:<0.0001) and increased mammary epithelial estrogen receptor (ERalpha) mRNA expression by approximately 50% (P:<0.0001; ERbeta mRNA was not detected in the primate mammary gland). Progesterone did not alter E2's proliferative effects, but testosterone reduced E2-induced proliferation by approximately 40% (P:<0.002) and entirely abolished E2-induced augmentation of ERalpha expression. Tamoxifen had a significant agonist effect in the ovariectomized monkey, producing a approximately threefold increase in mammary epithelial proliferation (P:<0.01), but tamoxifen also reduced ERalpha expression below placebo level. Androgen receptor (AR) mRNA was detected in mammary epithelium by in situ hybridization. AR mRNA levels were not altered by E2 alone but were significantly reduced by E2/T and tamoxifen treatment. Because combined E2/T and tamoxifen had similar effects on mammary epithelium, we investigated the regulation of known sex steroid-responsive mRNAs in the primate mammary epithelium. E2 alone had no effect on apolipoprotein D (ApoD) or IGF binding protein 5 (IGFBP5) expression, but E2/T and tamoxifen treatment groups both demonstrated identical alterations in these mRNAs (ApoD was decreased and IGFBP5 was increased). These observations showing androgen-induced down-regulation of mammary epithelial proliferation and ER expression suggest that combined estrogen/androgen hormone replacement therapy might reduce the risk of breast cancer associated with estrogen replacement. In addition, these novel findings on tamoxifen's androgen-like effects on primate mammary epithelial sex steroid receptor expression suggest that tamoxifen's protective action on mammary gland may involve androgenic effects.

Modulation of drug resistance by alpha-tubulin in paclitaxel-resistant human lung cancer cell lines

Beta(beta)-tubulin isotype variation has recently been implicated in the modulation of resistance to paclitaxel in human lung cancer cells and in primary human ovarian tumour samples. Whether alpha-tubulin is involved in drug resistance has not been reported. We have generated a paclitaxel-resistant cell line (H460/T800) from the sensitive human lung carcinoma parental cell line NCI-H460. The resistant cells are more than 1000-fold resistant to taxol and overexpress P-glycoprotein. Interestingly, H460/T800 cells also overexpress alpha- and beta-tubulin as detected by Western blot analysis. From Northern blot analysis, the mechanism of tubulin overexpression appears to be post-transcriptional. To understand whether alpha-tubulin plays a role in drug resistance, we transfected antisense human kalpha1 cDNA construct into the H460/T800 paclitaxel-resistant cells. The antisense clones displayed a reduced alpha-tubulin expression, and the cells were 45-51% more sensitive to paclitaxel and other known antimitotic drugs, compared with vector transfected controls. Complementary experiments of transfecting the sense kalpha1 cDNA into H460 cells conferred a 1.8- to 3.3-fold increase in the IC(50) of several antimitotic agents. Our study suggests that alpha-tubulin is one of the factors that contributes to drug resistance.

Cocaine use during pregnancy and intrauterine growth retardation: new insights based on maternal hair tests

Prenatal cocaine use is more accurately measured by maternal hair assay than by urine toxicology screening or self-report. To investigate the consequences of improved measurement, the authors ascertained cocaine use during pregnancy by maternal hair test, urine test, and self-report in a sample of 691 patients recruited from one New York City hospital in 1990-1992. Associations with intrauterine growth retardation, head circumference, and length of gestation were investigated. A positive hair test at delivery was not more strongly associated with birth weight (-38.1 g; 95% CI: -164, 88.3) or head circumference (-1.73 mm; 95% CI: -5.91, 2.44) than a positive urine test at delivery (-182 g (95% CI: -295, -69.8) and -6.11 mm (95% CI: -9.99, -2.24), respectively). Cocaine concentration in hair (which was higher if urine tests were positive) had a dose-response relationship with birth weight: a 27-g decrease (95% CI: -51.9, -1.04) with each log-unit increase in concentration. Birth weights were similar among infants of never users and infants of users who stopped using cocaine before delivery. Heavier use of cocaine, but not lighter use, was associated with intrauterine growth retardation, and exposure in late pregnancy was necessary to the association. Although maternal hair tests were instrumental in clarifying these relations, their clinical use is probably not warranted.

Cytonic acids A and B: novel tridepside inhibitors of hCMV protease from the endophytic fungus Cytonaema species

Two novel human cytomegalovirus protease inhibitors, cytonic acids A (1) and B (2), have been isolated from the solid-state fermentation of the endophytic fungi Cytonaema sp. Their structures as p-tridepside isomers were elucidated by MS and NMR methods.

The transmembrane protein semaphorin 6A repels embryonic sympathetic axons

Semaphorin 6A (Sema6A) (previously named Semaphorin VIa) is the originally described member of the vertebrate semaphorin class 6, a group of transmembrane semaphorins homologous to the insect semaphorin class 1. Although Sema-1a (previously named semaphorin I) has been implicated in axon guidance in insects, the function of Sema6A is currently unknown. We have expressed the extracellular domain of Sema6A in mammalian cells as either a monomeric or a dimeric fusion protein and tested for potential axon guidance effects on two populations of embryonic neurons in growth cone collapse and collagen matrix chemorepulsion assays. Sema6A was observed to induce growth cone collapse of sympathetic neurons with an EC50 of approximately 200 pM, although a 10-fold higher (EC50 of approximately 2 nM) concentration was necessary to induce growth cone collapse of dorsal root ganglion neurons. The activity of Sema6A is likely to depend on protein dimerization or oligomerization. Although Sema6A mRNA is expressed in complex patterns during embryonic development, it is strikingly absent from sympathetic ganglia. Sema6A is, however, expressed in areas avoided by sympathetic axons and in areas innervated by sympathetics, but before their arrival. Our results demonstrate that transmembrane semaphorins, like the secreted ones, can act as repulsive axon guidance cues. Our findings are consistent with a role for Sema6A in channeling sympathetic axons into the sympathetic chains and controlling the temporal sequence of sympathetic target innervation.

Can 16-18-year-old elite ballet dancers improve their hip and ankle range of motion over a 12-month period?

OBJECTIVE

To determine the effect of a 12-month intensive ballet training regimen on hip and ankle range of motion in male and female, first- and second-year professional dancers.

DESIGN

12-month longitudinal follow-up.

SETTING

National classical ballet school in Australia.

PARTICIPANTS

28 female and 20 male full-time ballet students with a mean +/- 1 SD, ages 16.8 +/- 0.8 and 17.7 +/- 1.2 years, respectively.

MAIN OUTCOME MEASURES

Degrees of range of motion of left and right sides for the following movements: standing plié in parallel-passive ankle dorsiflexion (DF); standing turnout in the balletic first position--lower leg external rotation (LLER); supine hip external rotation (ER); supine hip internal rotation (IR). An additional range of motion was calculated: external rotation below the hip joint (BHER) derived by subtracting hip ER from LLER.

MAIN RESULTS

In all subjects combined, hip and ankle ranges increased statistically on the right. However, the amount was generally minimal and most at the borderline of the amount of error associated with the measurement tool. While there was no change in LLER, there was a decrease in BHER. There were no overall gender differences, and year differences existed only for left hip ER and total hip ER with first-year dancers showing significant improvements in these ranges. For DF and sum of hip IR, first-year males and second-year females had increases in range. There was a negative relationship between baseline range and the amount of change over the 12 months.

CONCLUSIONS

Dancers ages 16-18 years who enter full-time ballet training did not augment their ankle dorsiflexion to any appreciable degree. Some, but certainly not all, increased their hip active external rotation over 12 months without increasing their total lower limb turnout. Hip ER was more likely to improve in the first-year rather than second-year student in this elite full-time training school.

A cost and performance evaluation of disposable and reusable biopsy forceps in GI endoscopy

BACKGROUND

Biopsy forceps are widely used in gastrointestinal endoscopy, and yet few data exist on the usage and costs associated with disposable versus reusable forceps.

METHODS

We prospectively measured the costs and operational performance of disposable and reusable forceps in 200 biopsy sessions; 100 sessions were performed using disposable forceps and 100 sessions were performed using reusable forceps. Total cost per use of the reusable forceps, including acquisition costs plus the costs of reprocessing per established guidelines, was determined. At the end of the study, the reusable forceps were disassembled to determine the cause of mechanical failures.

RESULTS

The total cost per use of the disposable forceps was $38. For the reusable forceps, the acquisition cost per forceps was $415 and the total reprocessing cost was $16.56 +/- 0.07 per forceps. For 10, 15 and 20 uses, reusable forceps costs were $58.06, $44.23, and $37.31, respectively. Reusable forceps malfunction at 11 to 15 uses was 5%; at 16 to 20 uses was 25%; and at 21 to 25 uses reached 80% (p < 0.001). Dismantling of the reusable forceps at the end of the study demonstrated coiled sheath kinking, rust in the forceps closure mechanism, bent spikes, and biomaterial contamination.

CONCLUSIONS

Up to 15 to 20 uses, disposable and reusable forceps costs were similar. If reusable forceps are used more than 20 times, then they are less expensive. However, in this range of uses, reusable biopsy forceps performance diminishes. With disposable biopsy forceps costing less than $40, cost differences between reusable and disposable forceps are minimal.

Cellular transport processes of aminoguanidine, a nitric oxide synthase inhibitor, in the opossum kidney cell culture line

Aminoguanidine has potential pharmacologic utility for diabetes and nitric oxide - mediated inflammation. Because aminoguanidine is positively charged at physiologic pH (pK(a) approximately 10), it is unlikely that simple diffusion is a predominant mechanism for cellular penetration. This study sought to determine the transport processes by which aminoguanidine, a cationic compound, traverses across cellular membranes. In cultured opossum kidney (OK) cell monolayers, aminoguanidine transport involved both saturable and non-saturable diffusion processes. At passage numbers below 67, the observed V(max) and K(m) for saturable influx were significantly lower than that observed at passages greater than 79 (V(max): low passage, 21.2+/-7.8 pmol/(min*mg protein), n=3; versus high passage, 129.7+/-24.3 pmol/(min*mg protein), n=3, P<0.05; K(m): low passage, 23.7+/-10.8 microM, n=3; versus high passage, 101.7+/-5.6 microM, n=3, P<0.05; mean+/-S.E.M.). Nonsaturable processes were not statistically different (k(ns): low passage, 1.6+/-0.1 pmol/(min*mg protein*microM), n=3; high passage, 1.1+/-0.2 pmol/(min*mg protein*microM) n=3). Saturable influx was temperature dependent, and independent of ATP energy, sodium gradients or changes in membrane potential. Other organic cations competitively inhibited and trans-stimulated saturable influx. Aminoguanidine influx was increased in the presence of an outwardly-directed proton gradient and was inhibited in the presence of an inwardly-directed proton gradient. Correspondingly, aminoguanidine efflux was trans79) express a saturable, bi-directional carrier-mediated process to transport aminoguanidine across cellular membranes.

Is there room for managed care in Canada? A preliminary inquiry of physicians

Managed care, which is becoming increasingly prevalent in the United States, is virtually absent in Canada. Yet managed care, if implemented judiciously, has the potential to provide comprehensive, high quality care while containing spiraling healthcare expenditures. Managed care is also the foundation of integrated health systems, which have been widely discussed during the past few years. Then why has Canada been so slow to accept managed care? Since physicians have a great deal of influence on how healthcare is ultimately delivered, a group of Ontario physicians was surveyed to determine their perceptions of managed care. It was found that physicians were knowledgeable about the cost-containment capabilities of managed care but had misperceptions about managed care with respect to quality of patient care, preventive services and necessary medical care. Education and further research are recommended so that any debate about managed care, integrated systems or alternative physician payment can be meaningful, objective, beneficial and accurate.

High-dose methotrexate for primary CNS lymphoma in the elderly

Primary central nervous system lymphoma (PCNSL) in the immunocompetent patient reaches a peak incidence in the sixth and seventh decades of life. This retrospective study reviewed the efficacy and tolerability of high-dose methotrexate (HDMTX) in an elderly patient population. Between May 1995 and September 1998, ten consecutive elderly patients with histologically proven PCNSL were treated with HDMTX. The median age was 72.5 years and eight patients (80%) were older than 70 years. HDMTX was well tolerated with no episodes of grade 4 toxicity nor febrile neutropenia. Toxicity included grade 3 nausea (1), grade 2 mucositis (2), and grade 2 asymptomatic elevation of liver transaminases (2). Grade 1 toxicity occurred in three patients with nausea, diarrhea, and mild reversible elevation in serum creatinine in one patient each. Six patients had a complete response and three patients achieved a partial response, giving an overall response rate of 90% (95% confidence interval, 56%-100%). The median overall survival for the cohort was 36 months (range 4-43 months). In summary, HDMTX is well tolerated in this elderly population with PCNSL and achieves response rates and median survival comparable with other chemotherapy or radiotherapy regimens.

Spontaneous activation of hamster oocytes in vitro

OBJECTIVES

To observe the time of spontaneous activation of hamster oocytes and to find out the early signs of hamster oocytes activation.

METHODS

First, 63 hamster oocytes including activated and non-activated oocytes (group A) and 51 non-activated oocytes (group B) were injected with human sperm and checked for fertilization after 16-18 hours. Then, 20 hamster oocytes were cultured in vitro in medium with or without calcium and examined under light microscope every half an hour up to 9 hours.

RESULTS

Under light microscope, hamster oocytes activation were observed to undergo 4 stages: metaphase II stage without meiotic spindle, appearance of meiotic spindle near the first polar body, protrusion of oolemma, and complete extrusion of second polar body with pronucleus formation. After culture for 1.5 hours in vitro, 30%-40% of the oocytes demonstrated meiotic spindle; but after 9 hours, 50% showed complete activation. Culture in medium without calcium showed a little delay in the process of activation. The earliest sign of spontaneous activation in hamster oocytes was the appearance of meiotic spindle near the first polar body. Although group A and B showed no difference, the damage rate was lower in group B (19.7% +/- 16.6%) than in group A (35.9% +/- 5.7%) (P = 0.08), whereas the fertilization rate (18.3% +/- 10.9%) was higher in group B than in group A (14.2% +/- 8.7%) (P = 0.135).

CONCLUSIONS

Hamster oocytes may be activated spontaneously early after their removal. It is important to recognize the earliest sign of spontaneous activation and perform intracytoplasmic sperm injection (ICSI) before it happens.

Combinatorial discovery process yields antimicrobial peptoids

N-alkylated glycine trimers are generically referred to as peptoids. The identification of antimicrobial peptoids from a statistically unbiased diverse combinatorial chemistry library led to the design of the optimization peptoid library that we describe in this manuscript. This optimization library was designed using structural information from the most active peptoids in the unbiased library. Screening of the optimization library for antimicrobial activity identified a single pool of peptoids with activity against both Staphylococcus aureus and Escherichia coli. The active peptoids from this pool were active against drug sensitive and drug resistant organisms and represent novel antibacterial compounds.

A nursing home outbreak of Clostridium perfringens associated with pureed food

OBJECTIVE

To investigate and ascertain the source of a nursing home outbreak of gastroenteritis in Melbourne in 1997.

METHOD

A retrospective cohort study. We obtained fecal and food samples and environmental swabs, and reviewed food handling.

RESULTS

There were 25 cases, and 21 of these had their meals pureed (liquidised). The relative risk for eating pureed food and becoming ill was 5.8 (95% CI 2.2-15.4). Clostridium perfringens and its enterotoxin was detected in nine fecal samples. Samples of pureed food tested positive for coliforms.

CONCLUSIONS

This outbreak was caused by C. perfringens contaminating pureed food. Food liquidising provides opportunities for re-contamination of cooked food through the use of contaminated equipment and deficiencies in food handling practices. Pureed foods should be reheated to 70 degrees C after liquidising to inactivate pathogens.

IMPLICATIONS

Health care facilities need to take specific precautions to manage the special hazards involved in preparing pureed food.

Characterization of novel antimicrobial peptoids

Peptoids differ from peptides in that peptoids are composed of N-substituted rather than alpha-carbon-substituted glycine units. In this paper we report the in vitro and in vivo antibacterial activities of several antibacterial peptoids discovered by screening combinatorial chemistry libraries for bacterial growth inhibition. In vitro, the peptoid CHIR29498 and some of its analogues were active in the range of 3 to 12 microg/ml against a panel of gram-positive and gram-negative bacteria which included isolates which were resistant to known antibiotics. Peptoid antimicrobial activity against Staphylococcus aureus was rapid, bactericidal, and independent of protein synthesis. beta-Galactosidase and propidium iodide leakage assays indicated that the membrane is the most likely target of activity. Positional isomers of an active peptoid were also active, consistent with a mode of action, such as membrane disruption, that does not require a specific fit between the molecule and its target. In vivo, CHIR29498 protected S. aureus-infected mice in a simple infection model.

Barriers to meeting the mental health needs of the Chinese community

BACKGROUND

This study aimed to identify the barriers encountered by Chinese people with mental health needs in England which hindered their obtaining appropriate help from the National Health Service (NHS).

METHODS

Attenders at Chinese community centres in health authority districts with resident Chinese population in excess of 2000 were invited to fill in a 12-item Chinese Health Questionnaire (12-CHQ). Individuals who scored two or above, indicating a high probability of a mental health problem, were invited to undertake a semi-structured interview.

RESULTS

A total of 401 completed the 12-CHQ. Eighty-six (21.4 per cent) screened positive and 71 (82.6 per cent) agreed to be interviewed. Although 70 (98.6 per cent) were registered with a general practitioner (GP), there were long delays before they made contact with health professionals, and the GP was the first port of call for help in only 27 (38.6 per cent) interviewees. Fifty-two (74.3 per cent) had encountered difficulties when they sought professional help. The main barriers were language, interviewees' perceptions of symptoms as somatic rather than psychiatric in origin, lack of knowledge about statutory services, and lack of access to bilingual health professionals. Doctors, particularly GPs, were pivotal in the management of their conditions. The majority were prescribed psychiatric medication with only a small number in contact with community psychiatric services. Unemployment and social exclusion were common. Stigma associated with mental illness and limited knowledge in the community were identified as the causes for the widespread discrimination experienced by the interviewees.

CONCLUSION

The mental health needs of these Chinese people were not adequately met by statutory services, nor could they rely on family and friends for care and support. Training for health service staff and access to health advocates are essential to maximize the effectiveness of health professional-patient contacts. The promotion of better understanding of mental illness by the Chinese community is important, and greater flexibility within the NHS is required to ensure those professionals with bilingual skills are used to the best effect.

Differential expression of NF1 type I and type II isoforms in sporadic borderline and invasive epithelial ovarian tumors

The NF1 gene, a putative tumor suppressor gene, contains a GAP related domain (GRD) which accelerates hydrolysis of ras-bound GTP to GDP, thereby converting the ras oncogene from its active to inactive form. Two forms of the NF1 GRD transcript (Type I and Type II) are differentially expressed in neuroectodermal tumor tissue relative to differentiated neural cells, and in gastric cancer cell lines relative to normal stomach mucosa. We measured relative expression of NF1 Type II and Type I isoforms in cultured normal and malignant human ovarian surface epithelial cells(HOSE) and in invasive and borderline ovarian tumor tissue. We demonstrated an 11-fold increase in Type II:Type I ratio in 7 HOSE cultures relative to eight ovarian cancer cell lines. Our findings indicate a significant decrease in Type II isoform expression and increase in Type I expression in ovarian cancer cells and tumor tissue relative to HOSE cells. We also demonstrate an increase in Type II:Type I ratio, and a decrease in cell proliferation rate in three ovarian cancer cell lines on treatment with retinoic acid. We propose that differential expression of the NF1 Type I and Type II isoforms is related to cellular differentiation in ovarian epithelial cancer and strategies based on alteration in NF1 isoform expression may have therapeutic potential in ovarian malignancies.

Influence of host genetics on the severity of coccidioidomycosis

Coccidioidomycosis, a mild flulike illness in approximately 40% of infected persons, progresses to severe pulmonary or disseminated disease in 1% to 10% of symptomatic cases. We examined host genetic influences on disease severity among class II HLA loci and the ABO blood group. Participants included African-American, Caucasian, and Hispanic persons with mild or severe disseminated coccidioidomycosis from Kern County, California. Among Hispanics, predisposition to symptomatic disease and severe disseminated disease is associated with blood types A and B, respectively. The HLA class II DRB1*1301 allele marks a pre-disposition to severe disseminated disease in each of the three groups. Reduced risk for severe disease is associated with DRB1*0301-DQB1*0201 among Caucasians and Hispanics and with DRB1*1501-DQB1*0602 among African-Americans. These data support the hypothesis that host genes, in particular HLA class II and the ABO blood group, influence susceptibility to severe coccidioidomycosis.

CSF antibiotic prophylaxis for neurosurgical patients with ventriculostomy: a randomised study

The value of prophylactic antibiotics for patients with ventricular catheter for monitoring and CSF drainage is uncertain. 228 patients were randomised to receive perioperative antibiotics only (Unasyn, Group I) or prolonged antibiotics for the presence of the ventricular catheter (Unasyn and Aztreonam, Group II). The incidence of intracranial and extracranial infection was documented prospectively. Group II patients had a significantly reduced incidence of CSF infection [3/115 (3%) vs 12/113 (11%), p = 0.01] and extracranial infections [23/115 (20%) vs 48/113 (42%), p = 0.002]. CSF pathogens in Group II patients were MRSA and Candida, whereas in Group I, Staphylococci, E coli and Klebsiella. Although prolonged antibiotic prophylaxis significantly reduced the incidence of serious CSF infection as well as extracranial infections, this policy did select resistant or opportunistic pathogens such as Candida and MRSA.

Human semaphorin K1 is glycosylphosphatidylinositol-linked and defines a new subfamily of viral-related semaphorins

The semaphorin family contains a large number of secreted and transmembrane proteins, some of which are known to act as repulsive axon guidance cues during development or to be involved in immune function. We report here on the identification of semaphorin K1 (sema K1), the first semaphorin known to be associated with cell surfaces via a glycosylphosphatidylinositol linkage. Sema K1 is highly homologous to a viral semaphorin and can interact with specific immune cells, suggesting that like its viral counterpart, sema K1 could play an important role in regulating immune function. Sema K1 does not bind to neuropilin-1 or neuropilin-2, the two receptors implicated in mediating the repulsive action of several secreted semaphorins, and thus it likely acts through a novel receptor. In contrast to most previously described semaphorins, sema K1 is only weakly expressed during development but is present at high levels in postnatal and adult tissues, particularly brain and spinal cord.

Community outbreak of psittacosis in a rural Australian town

BACKGROUND

Health authorities in Victoria, Australia were notified of three men from a rural town with atypical pneumonia, admitted to hospital over 8 days. Initial serological testing suggested Chlamydia psittaci as the cause. We did a case-control study to find risk factors for psittacosis.

METHODS

We searched for cases of pneumonia or severe flu-like illness through family physicians and the regional hospital. We selected three controls per case from the region's electoral roll. We collected blood for serological tests and administered questionnaires to all cases and controls.

FINDINGS

We found 16 cases of psittacosis and one died. Most cases were clustered within a small geographical area, with a median age of 58 years (range 23-76), 15 (94%) of whom were male. Keeping, handling, or feeding domestic or wild birds was not associated with illness. Cases spent a median of 17.5 h per week in their garden, compared with a median of 5.2 h for controls (p=0.04) and were more likely to have mowed lawns during the 3 weeks before onset of illness than controls (odds ratio 4.81 [95% CI 1.08-33.37]).

INTERPRETATION

We showed that psittacosis outbreaks are not limited to direct contact with birds and pose new challenges for disease control. Modifications may be needed to work outdoors to decrease the risk of psittacosis.

Somatostatin inhibits (d-Arg6, Pro9-NEt) salmon gonadotropin-releasing hormone- and dopamine D1-stimulated growth hormone release from perifused pituitary cells of chinese grass carp, ctenopharyngodon idellus

In this study, a heterologous radioimmunoassay (RIA) for grass carp GH has been validated and used to monitor the kinetics of GH release from perifused grass carp pituitary cells. To establish the anatomical specificity of GH antiserum used in this RIA, immunohistochemical staining was performed in grass carp pituitary sections. Somatotrophs recognized by this GH antiserum were located mainly in the proximal pars distalis without overlapping with gonadotrophs located in the same area or with lactotrophs located in the rostral pars distalis. The immunoreactivity of somatotrophs was abolished by preabsorbing GH antiserum with purified grass carp GH, suggesting that the possibility of a cross-reactivity of antiserum with other grass carp pituitary hormones is unlikely. Using 125I-labeled carp GH as the RIA tracer, parallelism was observed among the displacement curves of grass carp GH standard, grass carp serum, and culture medium conditioned by grass carp pituitary cells, suggesting that this RIA can be used to quantitate grass carp GH levels in biological samples. Using an in vitro column perifusion system, a superactive gonadotropin-releasing hormone (GnRH) analog (d-Arg6, Pro9-NEt)-sGnRH(sGnRHa, 0.3-30 nM), dopamine (DA, 0.1-10 muM), and the nonselective DA agonist apomorphine (0.1-10 muM) stimulated GH release from grass carp pituitary cells in a dose-dependent manner. The GH-releasing effect of DA was mimicked by the D1 agonists SKF38393 (0.1-10 muM) and SKF77434 (0.1-10 muM), but not by the D2 agonist LY171555 (3 muM). In addition, the GH response to DA (1 muM) was blocked by the D1 antagonist SCH23390 (5 muM) but not by the D2 antagonist (+/-) sulpiride (5 muM), suggesting that the GH-releasing action of DA is mediated through receptors resembling mammalian D1 receptors. Somatostatin-14 (SRIF14, 0.01-100 nM), unlike sGnRHa and DA, induced a dose-dependent suppression on basal GH release. At a high dose (100 nM), SRIF14 also abolished the GH responses to sGnRHa (100 nM), DA (10 muM), and the D1 agonist SKF38393 (3 muM). These results, as a whole, provide evidence that GH release in the grass carp is under the direct regulation of GnRH, DA, and SRIF at the pituitary cell level. The present study also suggests that DA D1 receptors are present in grass carp pituitary cells mediating the GH-releasing action of DA.

Dalteparin for deep venous thrombosis: a hospital-in-the-home program

OBJECTIVE

To assess the efficacy, safety and cost savings of home treatment of lower-limb deep venous thrombosis (DVT).

SETTING

A hospital-in-the-home treatment program.

PATIENTS

One hundred patients with acute lower limb DVT (53 proximal, 47 distal), and no contraindication to home treatment, were entered into the program from March 1995 to February 1997.

INTERVENTION

All patients received dalteparin, 200 units/kg subcutaneously, once daily for a minimum of five days, with commencement of oral anticoagulation (warfarin) on Day 2. Patients with proximal DVT had lung ventilation-perfusion scans performed and were admitted to hospital for at least 24 hours. Patients with distal DVT were discharged directly to home treatment.

MAIN OUTCOME MEASURES

Clinical responses and the results of sequential duplex ultrasonography at one week, one month, three months and six months.

RESULTS

There were no major, but six minor, bleeding complications, two of which led to dalteparin being withdrawn. Sixteen patients had lung ventilation-perfusion scans showing a high probability of pulmonary embolism. All were asymptomatic, and follow-up for at least three months showed no symptomatic thromboembolic events. Duplex ultrasonography showed progression of thrombosis in the first week of therapy in 13.2% of distal and 2.7% of proximal thromboses. Thereafter, distal DVT improved at a much greater rate than proximal DVT; after six months complete resolution was seen in 60.7% of distal and 18.5% of proximal thromboses, respectively. Cost saving was $197 per bed-day equivalent compared with inpatient care. At 15 months' follow-up, swelling and/or pain was reported by 49% of patients with distal DVT and 66% of those with proximal DVT.

CONCLUSIONS

Once-daily dalteparin therapy for DVT in a hospital-in-the-home setting was safe, efficacious and cost effective. However, DVT resolution is a slow process, with significant long term morbidity.

Unusual liver MR findings of Wilson's disease in an asymptomatic 2-year-old girl

We describe the unusual magnetic resonance (MR) findings of a case of Wilson's disease (WD) in an asymptomatic 2-year-old girl. Preenhanced computed tomography revealed multiple hyperdense areas in the liver. These lesions were hyperintense on T1-weighted and hypointense on T2-weighted MR images, results that might be ascribed to the paramagnetism of copper deposited in liver at a relatively early stage of the disease before severe liver cirrhosis had evolved.

Anticardiolipin IgG subclasses: association of IgG2 with arterial and/or venous thrombosis

OBJECTIVE

To determine whether the presence of anticardiolipin antibodies (aCL) of a specific IgG subclass is associated with clinical complications of the antiphospholipid antibody syndrome (APS) and whether polymorphisms of Fc receptors for IgG (FcgammaR) with differential binding preferences contribute to an increased risk of thrombotic complications.

METHODS

In 60 patients with IgG aCL, we assessed clinical complications of the APS, measured the level of antibody activity, and determined the IgG subclass distribution of aCL by a modified enzyme-linked immunosorbent assay (ELISA) with murine anti-human IgG subclass monoclonal antibodies. Selective IgG subclass adsorption studies were performed to determine the relative contribution of specific IgG subclasses to overall aCL activity. Fcgamma receptor IIA (FcgammaRIIA) genotypes of aCL patients with thrombosis and of non-systemic lupus erythematosus controls were determined by polymerase chain reaction amplification of genomic DNA and allele-specific probes.

RESULTS

IgG2 aCL, detected in 75% of the patients, was the major subclass of aCL. Selective adsorption studies demonstrated that IgG2, in contrast to IgG1, was the predominant subclass responsible for aCL reactivity. IgG2 aCL was the only subclass associated with clinical complications, specifically, arterial and/or venous thrombosis (P < 0.04). The presence of FcgammaRIIA-H131, a receptor expressed on platelets, monocytes, and endothelial cells and the only human FcgammaR which efficiently recognizes IgG2, was associated with thrombosis in aCL patients. Among 45 high-titer (>40 GPL [IgG phospholipid] units) aCL patients with thrombosis, 40% were homozygous for FcgammaRIIA-H131, compared with 25% of disease-free controls (P = 0.042).

CONCLUSION

While all 4 IgG subclasses are found in autoimmune aCL, only the presence of IgG2 is significantly associated with thrombotic complications. Reactivity in aCL ELISA is largely due to the presence of IgG2 in high-titer patients. The presence of IgG2 aCL, particularly in association with FcgammaRIIA-H131, may be a useful clinical predictor of increased thrombotic risk in patients with autoimmune IgG aCL. Allelic variants of FcgammaRIIA with distinct capacities to interact with IgG subclasses provide a mechanism for genetic susceptibility to an autoantibody-induced prothrombotic state.

Small bowel obstruction due to phytobezoar: CT diagnosis

We report two cases of small bowel obstruction (SBO) due to phytobezoar impaction. In both cases, computed tomography (CT) demonstrated a well-defined, ovoid intraluminal mass with mottled gas pattern within the dilated small bowel at the site of obstruction and an abruptly collapsed lumen beyond the lesion. Recognition of these CT findings allows specific preoperative diagnosis of SBO owing to this uncommon lesion.

Modifications in high-density lipoprotein lipid composition and structure alter the plasma distribution of free and liposomal annamycin

Recent studies have shown that changes in lipoprotein cholesterol and triglyceride concentration alters the plasma distribution of free (Ann.) and liposomal annamycin (LAnn) and that the majority of Ann. is associated with high-density lipoproteins (HDL) following the incubation in plasma of LAnn. To demonstrate that alterations in HDL lipid composition and HDL structure may influence the plasma distribution of Ann. and LAnn, Ann. and LAnn (20 micrograms/mL) were incubated in plasma pretreated with dithionitrobenzoate (DTNB, a compound which inhibits the conversion of free cholesterol to esterified cholesterol) 18 h prior to the experiment or in untreated plasma for 60 min at 37 degrees C. In addition, Ann. and LAnn were co-incubated with DTNB in plasma for 60 min at 37 degrees C. Following incubation the plasma was separated into its HDL, low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), and lipoprotein-deficient plasma (LPDP) fractions by ultracentrifugation and assayed for Ann. by fluorimetry. The HDL plasma cholesterol:triglyceride concentration ratio was significantly decreased following 18 h of DTNB pretreatment compared to untreated plasma controls. No significant differences in LDL/VLDL plasma cholesterol:triglyceride concentration ratio following 18 h of DTNB pretreatment was observed. An increased number of discoidal HDL particles were observed following 18 h of DTNB pretreatment. When Ann. was incubated in plasma pretreated with DTNB for 18 h the percentage of Ann. recovered in the HDL, LDL, and VLDL fractions significantly increased. However, the percentage of Ann. recovered within the LPDP fraction was significantly decreased. When LAnn was incubated in plasma pretreated with DTNB for 18 h the percentage of Ann. recovered in the HDL fraction significantly decreased. The percentage of Ann. recovered in the LPDP fraction significantly increased when LAnn was incubated in plasma pretreated with DTNB for 18 h. No significant differences in Ann. lipoprotein distribution were observed when Ann. and LAnn were co-incubated with DTNB in plasma for 1 h. These findings suggest that the cholesterol:triglyceride concentration ratio and physical structure of HDL maybe important in defining the capacity of HDL to sequester Ann.

Progressive multifocal leukoencephalopathy: unusual MR findings

A case of progressive multifocal leukoencephalopathy (PML) with a classic clinical presentation but with unusual pathological and radiographic findings is reported. The pathology revealed evidence of prior hemorrhage, and imaging studies revealed focal cerebral atrophy as well as contrast enhancement on MR scans. The contrast enhancement was visible only by utilizing magnetization transfer pulses on T1-weighted scans. The case report indicates that image criteria for PML may need to be redefined in the future.

Structural investigation of the capsular polysaccharide produced by a novel Klebsiella serotype (SK1). Location of O-acetyl substituents using NMR and MS techniques

The capsular polysaccharide of Klebsiella SK1 was investigated by methylation analysis, Smith degradation, and 1H NMR spectroscopy. The oligosaccharides (P1 and P2) obtained by bacteriophage phi SK1 degradation of the polymer were studied by methylation analysis, and 1D- and 2D-NMR spectroscopy. The resulting data showed that the parent repeating unit is a branched pentasaccharide having a structure identical to the revised structure recently proposed for Klebsiella serotype K8 capsular polysaccharide. [Formula: see text] The 2D-NMR data showed that one third of the glucuronic acid residues in the SK1 polymer are acetylated at O-2, O-3, or O-4. FABMS studies confirmed the presence of monoacetylated glucuronic acid residues. Thus, the relationship between the Klebsiella K8 and SK1 polymers is akin to that found for Klebsiella polysaccharides K30 and K33, which have been typed as serologically distinct yet their structures differ only in the degree of acetylation.

Peptoids: a modular approach to drug discovery

Peptoids, oligomers of N-substituted glycines, are described as a motif for the generation of chemically diverse libraries of novel molecules. Ramachandran-type plots were calculated and indicate a greater diversity of conformational states available for peptoids than for peptides. The monomers incorporate t-butyl-based side-chain and 9-fluorenylmethoxy-carbonyl alpha-amine protection. The controlled oligomerization of the peptoid monomers was performed manually and robotically with in situ activation by either benzotriazol-1-yloxytris(pyrrolidino)phosphonium hexafluorophosphate or bromotris(pyrrolidino)phosphonium hexaflurophosphate. Other steps were identical to peptide synthesis using alpha-(9-fluorenylmethoxycarbonyl)amino acids. A total of 15 monomers and 10 oligomers (peptoids) are described. Preliminary data are presented on the stability of a representative oligopeptoid to enzymatic hydrolysis. Peptoid versions of peptide ligands of three biological systems (bovine pancreatic alpha-amylase, hepatitis A virus 3C proteinase, and human immunodeficiency virus transactivator-responsive element RNA) were found with affinities comparable to those of the corresponding peptides. The potential use of libraries of these compounds in receptor- or enzyme-based assays is discussed.

Activated Val-12 ras p21 in cell culture fluids and mouse plasma

Activation of ras oncogenes has been associated with a variety of cancers as well as their precursor lesions. Ras proteins activated by substitutions at amino acid positions 12, 13 or 61 have not been identified in normal tissues and therefore their detection may have clinical value. In this study our objective was to determine whether activated ras proteins could be released into the extracellular environment. To test this hypothesis, we used ras-transformed NIH3T3 cells that express an activated p21 containing valine (Val-12 p21) at position 12 instead of the normal glycine (Gly-12 p21) and a monoclonal antibody (mAb) designated DWP that is specific for the activated Val-12 ras proteins. Culture fluids collected from NIH3T3 cells transformed by the activated Val-12 p21 were shown, using mAb DWP in a sandwich ELISA format, to contain the activated Val-12 p21. In contrast, culture fluids from non-Val-12-containing cells were unreactive with mAb DWP. PSV-LM-EJ cells which overexpress the activated Val-12 p21 were injected subcutaneously (SQ) into nude mice to produce tumors. At the time of gross tumor appearance (14-21 days after tumor cell inoculation), plasma was collected from the PSV-LM-EJ tumor-bearing mice as well as from a series of control mice. Employing mAb DWP as a detection reagent in the sandwich ELISA format, we were able to detect the Val-12 p21 in the plasma of the PSV-LM-EJ tumor-bearing mice. Activated Val-12 p21 was not present in the plasma of non-tumor-bearing mice, or in the plasma of mice bearing SQ tumors composed of non-Val-12 p21 ras-transformed cells. This report is the first description of an activated ras protein (Val-12 p21) in the plasma of tumor-bearing mice and demonstrates that the results of the Val-12 p21-specific ELISA could be validated with Western blot format.