Exploring the gray areas of informed consent

Learn your role in informed consent and explore the gray areas, including circumstances when consent may be valid even if the patient wasn't fully informed.

Ultra-high throughput screen of two-million-member combinatorial compound collection in a miniaturized, 1536-well assay format

Results of a complete survey of the more than 2-million-member Pharmacopeia compound collection in a 1536-well microvolume screening assay format are reported. A complete technology platform, enabling the performance of ultra-high throughput screening in a miniaturized 1536-well assay format, has been assembled and utilized. The platform consists of tools for performing microvolume assays, including assay plates, liquid handlers, optical imagers, and data management software. A fluorogenic screening assay for inhibition of a protease enzyme target was designed and developed using this platform. The assay was used to perform a survey screen of the Pharmacopeia compound collection for active inhibitors of the target enzyme. The results from the survey demonstrate the successful implementation of the ultra-high throughout platform for routine screening purposes. Performance of the assay in the miniaturized format is equivalent to that of a standard 96-well assay, showing the same dependence on kinetic parameters and ability to measure enzyme inhibition. The survey screen identified an active class of compounds within the Pharmacopeia compound collection. These results were confirmed using a standard 96-well assay.

P'-extended alpha-ketoamide inhibitors of proteasome

A series of potent P'-extended alpha-ketoamide inhibitors of chymotrypsin-like activity of proteasome is described.

Sequence heterogeneity of the ferripyoverdine uptake (fpvA), but not the ferric uptake regulator (fur), genes among strains of the fluorescent pseudomonads Pseudomonas aeruginosa, Pseudomonas aureofaciens, Pseudomonas fluorescens and Pseudomonas putida

Pseudomonas aeruginosa, Pseudomonas aureofaciens, Pseudomonas fluorescens and Pseudomonas putida are of importance to medicine, agriculture and biocycling. These microbes acquire ferric ion via the use of the siderophores pyochelin and the family known as the pyoverdines or pseudobactins. The ferric uptake regulator (fur) gene is responsible, at least in part, for the regulation of siderophore synthesis and uptake in P. aeruginosa. To determine whether the organisms contain single or multiple homologues of the siderophore-related genes fpvA (ferripyoverdine uptake) and fur, and whether these homologues displayed sequence heterogeneity, their chromosomal DNAs were probed with fur and fpvA sequences. As a representative of a non-fluorescent pseudomonad, the bacterium Burkholderia (Pseudomonas) cepacia was also examined. The pseudomonads all contained fpvA- and fur-like homologues, and heterogeneity was observed among the different species. The presence of two or more fpvA-like genes is indicated in all of the fluorescent pseudomonads surveyed. In contrast, B. cepacia DNA either did not hybridize to these probes, or did so only very weakly, suggesting that fur- and fpvA-like homologues are either absent or significantly different in B. cepacia compared to the fluorescent pseudomonads examined.

P2-achiral, P'-extended alpha-ketoamide inhibitors of calpain I

A series of potent P2-achiral, P'-extended alpha-ketoamide inhibitors of calpain I is described.

Diagnosis of congenital toxoplasmosis at birth: what is the value of testing for IgM and IgA?

Recommendations vary on the best combination of tests to use for the diagnosis of subclinical congenital toxoplasmosis at birth. The diagnostic accuracy of IgM and IgA tests was assessed in the context of routine clinical practice on 233 newborns with congenital toxoplasmosis and 661 healthy controls. IgM/IgA sensibility and specificity were compared in cord and postnatal samples. Both tests were considerably more specific in neonatal blood (IgM: 98%; IgA: 100%) than in cordblood (IgM: 85%; IgA: 88%). Sensitivity for IgM and IgA was not significantly different in neonatal blood (61% and 60%, respectively) and cord blood (67% and 54%, respectively). Combining IgM and IgA increased the overall sensitivity to 73% without any significant loss in specificity (98%). The influence of the date of maternal infection on the sensitivity and negative predictive value was also clearly demonstrated.

CONCLUSION

Because of their relatively low cost compared to more sophisticated methods, IgM and IgA tests should remain the main method for the routine diagnosis of congenital toxoplasmosis although follow up is essential to identify the Ca. 25% of infected children who are missed at birth on the basis of these tests.

Mother-to-child transmission of toxoplasmosis: risk estimates for clinical counselling

BACKGROUND

Women who acquire toxoplasmosis infection during pregnancy (in most cases detected through serological screening) require counselling about the risk of congenital infection and its clinical sequelae. Reliable estimates of risk are not currently available. We undertook an analysis of data from women referred to the toxoplasmosis reference laboratory, Lyon, France, between 1987 and 1995.

METHODS

Information was collected from clinical notes kept at the laboratory and, where necessary, from the relevant obstetrician or paediatrician via telephone. Methods were developed to derive estimates of the risk of congenital toxoplasmosis by exact duration of gestation at maternal seroconversion.

FINDINGS

We analysed obstetric and paediatric data on 603 confirmed maternal toxoplasmosis infections. At least 564 women received antiparasitic drugs according to a standard protocol. Congenital infection status was ascertained in 554 cases, and infected children were followed-up for a median of 54 months. The overall maternal-fetal transmission rate was 29% (95% CI 25-33), which masked a sharp increase in risk with duration of gestation from 6% at 13 weeks to 72% at 36 weeks. However, fetuses infected in early pregnancy were much more likely to show clinical signs of infection. These effects counterbalance, and women who seroconverted at 24-30 weeks of gestation carried the highest risk (10%) of having a congenitally infected child with early clinical signs who was thus at risk of long-term complications.

INTERPRETATION

This information will assist the clinical counselling of pregnant women diagnosed with acute toxoplasmosis and may guide individual decisions on investigative and therapeutic options. Further studies are required to determine the long-term risks of clinical symptoms and disability due to congenital toxoplasmosis.

Correction of the PNH defect by GPI-anchored protein transfer

Hemolytic anemia is a major feature of paroxysmal nocturnal hemoglobinuria (PNH). Intravascular red blood cell (RBC) destruction is caused by increased sensitivity of the abnormal erythrocyte to complement-mediated lysis, due to the GPI absence of a membrane-bound glycosylphosphatidylinositol (GPI)-linked protein, which functions as an inhibitor of reactive lysis (CD59). Both in vivo and in vitro models have suggested the feasibility of cell-to-cell transfer of GPI proteins, and patients with hemolysis could potentially benefit from transfer of CD59 to their deficient erythrocytes. We studied the ability of RBC components prepared from outdated packed RBC collections, as well as high-density lipoprotein (HDL) preparations, rich in CD55 and CD59, to promote protein transfer, as assessed by flow cytometry, immunoblotting, and susceptibility to complement-mediated lysis. By flow cytometry, CD55 and CD59 were present on RBC-derived microvesicles that stained with an antiglycophorin antibody Ab; in addition, soluble CD59 and CD55 were detected by immunoblot in soluble fractions eluated from RBC units stored for more than 35 days, but not in fresh blood. Both commercial HDL preparations and those prepared in our laboratory contained CD55 and CD59, as assayed by immunoblot. When RBC that were deficient (GPI)-anchored protein, obtained from five patients, with PNH were incubated with HDL preparations for 2 to 4 hours, there was significant transfer of both proteins to the cell surface, as demonstrated by flow cytometry. Washed RBC microvesicles, prepared by ultrasonification, also mediated transfer of GPI-linked proteins to deficient RBC. Pretreatment of microvesicles, RBC eluate preparations, and HDL with phosphatidylinositol-specific, phospholipase C, abrogated protein transfer to deficient cells, indicating that increased cell-associated CD55 and CD59 levels were related to insertion of the intact GPI moiety, rather than to simple adhesion. PNH RBC that were exposed to HDL, RBC eluate preparations, or microvesicles demonstrated decreased in vitro complement-mediated hemolysis in the Ham test. Transfer of GPI-linked proteins from soluble preparations containing CD55 and CD59 to PNH erythrocytes is feasible and may have clinical utility.

P2-proline-derived inhibitors of calpain I

The syntheses and biological activities of a series of calpain I inhibitors, derived from D- and L-Pro, are described.

Preoperative assessment criteria and patient teaching for ambulatory surgery patients

Today's trend is to have the surgical patient return to the comfort of his or her home rather than be admitted to the hospital for expensive nursing and medical care. The perioperative team must initially assess the patient's American Society of Anesthesiology status, anxiety level, food and drugs to which he or she may be allergic, and skin integrity; obtain a medical and surgical history and consent; review laboratory, electrocardiogram, and radiological results; and perform preoperative teaching (e.g., which medications to take or withhold preoperatively, when to withhold food and fluids) and postoperative teaching (e.g., catheter care, dressing changes). In addition, the nurse needs to anticipate and be prepared for medical emergencies such as airway management problems and malignant hyperthermia. The age of the patient (e.g., pediatric and geriatric age groups) and preoperative disease states and their severity also need to be recognized as they impact on the perioperative outcome. The assessment phase is one of the most important phases in the perioperative experience. Proper evaluation is the key to success for positive surgical outcomes. Given the time constraints in the ambulatory surgical setting, assessing and teaching the patient on the day of surgery is not feasible or appropriate. Reaching out to the patient a few days before surgery either in the patient's home, in the ambulatory surgery center, or by telephone is the ultimate goal.

Overexpression of the fanconi anemia group C gene (FAC) protects hematopoietic progenitors from death induced by Fas-mediated apoptosis

Fanconi anemia is a rare, inherited disorder characterized by bone marrow failure, congenital malformations, and cancer susceptibility. The group C Fanconi anemia gene, FAC, identified by expression cloning methods, encodes a protein of unknown function that may be involved in the response to apoptotic stimuli. Hematopoietic progenitor cells from Fac knock-out mice are hypersensitive to IFN-gamma, a molecule that can induce apoptosis through up-regulation of the Fas death receptor. In this study, we used FAC-overexpressing transgenic mice to examine the relationship between FAC and Fas-triggered cell death. Hematopoietic progenitors from FAC-transgenic mice were up to 10-fold less sensitive to the cytolytic effect of Fas-ligation. Our experiments implicate FAC in the regulation of apoptosis mediated by the Fas death receptor.

Development of scales to measure psychosocial care needs of children with seizures and their parents. 1

There is little research and no self-report assessment instruments available to guide nurses in the provision of psychosocial care to children with seizures and their families. Information on the development of two instruments, Report of Psychosocial Care Scale and Child Report of Psycyhosocial Care Scale, and their use in a research study to measure psychosocial care of children with new-onset seizures and their parents are presented in three parts. This first article describes development and initial testing of their psychometric properties. The second article, Part 2, "Psychosocial Care Needs of Parents of Children with New-Onset Seizures," describes results from the use of the parent scale with mothers and fathers of children with new-onset seizures. The third article, Part 3, "Psychosocial Care Needs of Children with New-Onset Seizures," reports findings from the use of the child scale with children ages 8-14 years with new-onset seizures.

Psychosocial care needs of children with new-onset seizures. 2

The Child Report of Psychosocial Care Scale was used to measure children's satisfaction with health care received, need for information and support and seizure-related concerns and fears in children with new-onset seizures. The sample of 63 children (33 girls and 30 boys), 8-14 years, completed the scale two times, 3 months and 6 months after their first seizure. Results indicated that children need the most nursing care in two areas: information related to the seizure condition, especially managing their condition, and support, in the form of talking to other children with seizures. The scale provides direction for tailored nursing interventions that will meet the specific needs of children with seizures for information and support.

Psychosocial care needs of parents of children with new-onset seizures. 3

The Parent Report of Psychosocial Care was developed to address the concerns, needs for care and satisfaction with care received of parents of children with new-onset seizures. Parents were interviewed three months and six months after their child's first seizures using the instrument. Mothers especially identified continued needs for information and support and were worried about unlikely events such as brain tumors and death. The results from this study indicate that parents' needs for information and support need to be assessed at every encounter with the health care system during the first 6 months after the child's first seizure.

An alternative synthesis of peptidyl alpha-keto-2-oxazolines

Application of Wipf's protocol to generate alpha-keto-2-oxazolines is described.

Applications of Ion Microscopy and In Situ Electron Microscopy to the Study of Electronic Materials and Devices

: We discuss the application of ion microscopy and in situ electron microscopy to the study of electronic and optical materials and devices. We demonstrate how the combination of in situ transmission electron microscopy and focused ion beam microscopy provides new avenues for the study for such structures, enabling extension of these techniques to the study of dopant distributions, nanoscale stresses, three-dimensional structural and chemical reconstruction, and real-time evolution of defect microstructure. We also discuss in situ applications of thermal, mechanical, electrical, and optical stresses during transmission electron microscopy imaging.

Transfection of interleukin-12 cDNAs into tumor cells induces cytotoxic immune responses against native tumor: implications for tumor vaccination

Interleukin-12 (IL-12) is a heterodimeric cytokine that is central to the development of T helper 1-dependent cellular immunity. Although this cytokine has potential therapeutic application as an antineoplastic agent, the systemic infusion of IL-12 has led to toxic fatalities; hence, restriction of expression of IL-12 to the microenvironment of target tumor cells has obvious appeal. In this study, we examined whether tumor cells that were liposome-transfected with IL-12 could enhance the induction of cytolytic lymphocyte immunity to the native tumor. The plasmid expression vector that we used has several useful features including replication to high copy number as an episome and a polycistronic message enabling the production of both the p35 and p40 subunits of IL-12 without alternative splicing; up to 3 ng/mL/10(6)/48 hours of IL-12 was produced following transfection. Tumor cells transfected with IL-12 were superior to untransfected cells in the induction of lymphocyte-mediated cytolysis. IL-12 transfectants induced a heterogeneous population of natural killer, lymphokine activated killer, and cytolytic T lymphocytes, the latter of which exhibited tumor-specific activity. Our studies suggest that liposome-mediated transfection of tumor cells with an episomal, high copy number plasmid vector expressing both IL-12 subunits is a promising approach to cancer vaccination, a strategy that could be implemented ex vivo in treating malignancies such as metastatic ovarian cancer.

Responsibilities of the preoperative holding area nurse

The preoperative holding area is an important, but often over-looked, area in the surgical suite. This area, however, is where the majority of surgical patients and their family members have their first direct contact with perioperative staff members. The preoperative holding area can provide the environment for calming, informative interactions that should help patients prepare for their surgical procedures. The preoperative holding area nurse's primary responsibility is to provide information and emotional support for patients and their family members, to ensure that all preoperative data have been accumulated, and to maintain patients' baseline hemodynamic statuses.

Ciprofloxacin-resistant Escherichia coli emerging in a rehabilitation medical center

A retrospective review of laboratory records from 1988 to 1996 has shown an increased rate of ciprofloxacin-resistant (cip(r)) Escherichia coli in our rehabilitation center. Resistance increased from 0.6% in 1989 to 5.9% in 1996. Of 7870 E. coli strains isolated during this period, 257 cip(r)-E. coli were recovered from 257 patients. The majority (96%) of these resistant strains were isolated from the urine samples. One hundred and twenty strains of cip(r)-E. coli were also resistant to four other fluoroquinolones. MICs ranging from 64 to 512 micrograms/mL were observed in 75% of the strains and > or = 1028 micrograms/mL in 6.4% of the strains. Resistance to ciprofloxacin was due to possible mutations in topoisomerase gyrA.

Malignant hyperthermia

Malignant hyperthermia (MH) is a medical emergency that all perioperative nurses should be prepared to handle. Patients with the inherited MH trait have a rare skeletal muscle disease that causes them to develop life-threatening hyperthermia (ie, body temperatures of 43.3 degrees C [110.0 degrees F] or higher) at the time MH-triggering agents are administered to induce general anesthesia or shortly thereafter. The incidence of MH episodes is reported to be 1 in every 12,000 pediatric anesthetic procedures and 1 in every 40,000 adult anesthetic procedures. The MH syndrome also is characterized by continuous skeletal muscle rigidity, hypermetabolism, hypercapnia, tachypnea, and tachycardia that result in cardiac arrest and death if left untreated. Perioperative staff members' knowledge of MH, the care of MH-susceptible patients, and adequate preparation for MH crises are the cornerstones of successful patient outcomes to this life-threatening syndrome.

Evidence for mediation of L-2-chloropropionic acid-induced delayed neuronal cell death by activation of a constitutive nitric oxide synthase

1. Delayed neuronal cell death elicited by excess excitatory amino acid concentrations has been strongly implicated in many neurological disorders including head trauma, stroke, motor neurone disease and Huntington's disease. We have used the neurotoxin, L-2-chloropropionic acid (L-CPA) to model cellular events in vivo leading to delayed neuronal cell loss which is confined to the cerebellar cortex and can be prevented by inhibitors of nitric oxide synthase such as NG-nitro-L-arginine methyl ester. 2. Experiments were performed to determine whether the constitutive nitric oxide synthase (NOS) or inducible form of NOS (iNOS) was responsible for the neuronal cell death. Activation of NOS was confirmed by a 39% increase in cerebellar total nitrate and nitrite concentrations in L-CPA-treated brains, as compared to controls (controls = 2.53 +/- 0.10; L-CPA treated = 3.51 +/- 0.31 nmol mg-1 protein, P < 0.01 Student's t tests, n = 6, mean +/- s.e.mean). Biochemical measurements of total NOS activity were made in homogenates of cerebellum 6 h and 48 h following L-CPA administration, times at which L-CPA concentrations are maximal in brain and a time when there is a high proportion of cerebellar granule cell death, respectively. NOS activity as measured by the amount of [3H]-arginine converted to [3H]-citrulline, did not reveal any difference between controls (rats dosed with water) and animals dosed with L-CPA at either 6 or 48 h following dosing. Furthermore the ability of three NOS inhibitors, NG-nitro-L-arginine, 7-bromo-3-nitroindazole and S-methylisothiourea to block the conversion of [3H]-citrulline to [3H]-arginine was identical at 6 and 48 h time points in control and L-CPA treated rats. 3. Quantitative autoradiography using [3H]-NG-nitro-L-arginine was used to measure the relative anatomical distribution and amount of NOS enzyme in the cerebellum of controls and L-CPA-treated rats 48 h following dosing. There was no significant alteration in the binding of [3H]-NG-nitro-L-arginine to granular and molecular layers of the cerebellum of control and L-CPA-treated rat brains. 4. Western blotting using antibodies against the inducible NOS enzyme failed to detect the protein in cerebellums of L-CPA-treated rats when measured 48 h after L-CPA dosing. 5. In conclusion, the increase in cerebellar nitrate/nitrite concentrations in L-CPA-treated rats provides further evidence for activation of NOS in the cerebellum following administration of L-CPA. The failure to demonstrate an increase in NOS activity at 6 or 48 h in L-CPA-treated rats as compared to controls suggests that the source of nitric oxide responsible for the granule cell death must originate from the constitutive NOS enzyme, probably the neuronal form which is highly enriched in the cerebellum. This hypothesis was further substantiated by Western blotting and quantitative autoradiography.

Spatial Patterns of Belonolaimus spp. Among and Within Citrus Orchards on Florida's Central Ridge

A survey was initiated to determine the incidence of Belonolaimus spp. (sting nematodes) in citrus orchards in the central ridge region of Florida, following widespread damage by these nematodes to young trees replanted after freezing weather in 1989-90. Sting nematodes were detected in 50% of 210 samples and in 64% of 84 orchards surveyed. More orchards in Polk County were infested with sting nematodes (82%) than in counties to the north (36%) or south (48%). Principal component analysis of morphometric data separated six of seven sting nematode populations in northeastern Polk County from six populations in adjacent regions. Stylet:tail ratio for nematodes in northeastern Polk County tend to be > 1.0 and were << 1.0 for all other populations. Patchiness of nematodes within an orchard was associated with stunted trees (23% smaller), reduced root mass density (25% lower), and low fruit yield (57% reduction). Soil texture did not vary among trees of different size in the orchard, but soil water potential between irrigation events was highest beneath small trees with low root mass density. Results of the survey indicate that the incidence of sting nematodes in orchards on the central ridge is much higher than previously estimated and that sting nematodes can cause substantial damage in replanted orchards. Further research is needed to evaluate the significance of sting nematode population variability and its relationship to citrus crop loss in Florida.

Possible role of nitric oxide in the development of L-2-chloropropionic acid-induced cerebellar granule cell necrosis

1. L-2-Chloropropionic acid (L-CPA) produces selective neuronal cell necrosis in rat cerebellum when administered orally at 750 mg kg-1 that is mediated in part through activation of N-methyl-D-aspartate (NMDA) receptors. Cerebellar granule cell death occurs between 30 and 36 h following L-CPA administration exhibiting a number of features in common with excitatory amino acid-induced cell death. We have used this in vivo model to examine the neurochemical processes following L-CPA-induced activation of NMDA receptors leading to neuronal cell death in the rat cerebellum. 2. The effects of a number of compounds which potently block nitric oxide synthase in vitro were examined on L-CPA-induced neurotoxicity 48 h following L-CPA dosing, to discover whether the neuronal cell death is mediated in part by excessive nitric oxide generation. Four inhibitors were studied, NG-nitro-L-arginine (L-NOARG), NG-nitro-L-arginine methyl ester (L-NAME), NG-iminoethyl-L-ornithine (L-NIO) and 3-bromo-7-nitroindazole (BrNI). 3. L-NAME (50 mg kg-1, i.p. twice daily) and BrIN (50 mg kg-1, i.p. twice daily) administration prevented the L-CPA-induced loss of granule cells which can reach up to 80-90% of the total cell number in rats treated with L-CPA alone. L-NOARG (50 mg kg-1, i.p. twice daily) and L-NIO administered at either 25 or 100 mg kg-1, twice daily did not produce any significant protection against L-CPA-induced neurotoxicity. 4. Both L-NAME and BrIN also prevented the L-CPA-induced increase in cerebellar water content and sodium concentrations. L-NIO when administered at the highest doses prevented the increase in cerebellar sodium concentration but not water content. L-NIO and L-NOARG were ineffective in preventing the L-CPA-induced increases in cerebellar water and sodium concentrations. 5. L-CPA-induced reductions in cerebellar aspartate and glutamate concentrations and increases in glutamine and GABA concentrations were prevented by L-NAME and BrIn, but not by L-NIO or L-NOARG. Also reductions in L-[3H]-glutamate binding to glutamate ionotrophic and metabotrophic receptors in the granule cell layer of rat cerebellum was prevented by L-NAME and BrIN, but not L-NIO or L-NOARG. 6. In conclusion, the neuroprotection offered by L-NAME and BrIN suggests that L-CPA-induced cerebellar granule cell necrosis is possibly mediated by or associated with excessive generation of nitric oxide. The inability of nitric oxide synthase inhibitors, L-NOARG and L-NIO to afford protection may result from their limited penetration into the brain (L-NIO) or rapid dissociation from the enzyme.

Anemia and the transition of nomadic hunter-gatherers to a sedentary life-style: follow-up study of a Kalahari community

Iron profiles of communities of hunter-gatherers and former hunter-gatherers conducted between 1969 and 1987 at Dobe in the Kalahari Desert of Botswana exhibited pronounced differences during periods of rapid culture change. The loss of good health and particularly the increase in anemia through time was attributed to notable changes in diet, although changes in mobility patterns were considered a secondary cause. In 1988 and 1989, studies were conducted at Kutse, also in the Kalahari Desert of Botswana, to ascertain the frequency of anemia at a recently sedentary community in which residents still relied primarily on wild animals for meat. Although not identical, the hematological presentation in 1989 was similar to that in 1988. The studies together suggest that our findings characterize the pattern of health and disease at Kutse, which is unrelated to any specific year or to diet. Additional measures of disease, specifically ESR (erythrocyte sedimentation rate) and oral temperatures, support an interpretation of anemia of chronic disease as the cause of hypoferremia at Kutse. Morbidity is high, in spite of adequate diets, because the residents are transitional from a nomadic to a sedentary lifestyle and from a relatively dispersed to an aggregated settlement pattern. These changes have introduced new health problems.

Characteristics of pregnant HIV-1 infected women in Europe. European Collaborative Study

There is a growing number of infected women in Europe and an increasing proportion of these have acquired their infection through heterosexual contact. Most infected women are of childbearing age and thus increasing numbers of children are at risk of acquiring infection. In this paper we examine the socio-demographic characteristics and trends in mode of acquisition of infection of 1690 infected women from 7 countries enrolled in the European Collaborative Study, a prospective multi-centre study of children born to women known to be HIV infected at or before the time of delivery. The majority of women were white, primiparae, married or cohabiting and born in Europe. Two-thirds had a history of injecting drug use (IDU), most commonly involving heroin. Although patterns of transmission varied by centre, there was a relative increase in heterosexual transmission over the study period. A history of needle-sharing among IDUs was common, but needle-sharing during pregnancy significantly declined between 1987 and 1994.

Detection of virus in vertically exposed HIV-antibody-negative children

BACKGROUND

HIV-infected mothers can transmit their infection to their children in utero or at delivery (vertical transmission). There have been cases of children who were reported as acquiring infection vertically and later clearing the infection. We report the frequency of this phenomenon in a European cohort study.

METHODS

In four centres of the European Collaborative Study of children born to HIV-infected mothers, 299 children became HIV-antibody-negative and 264 of these had been followed up with virus culture and PCR for viral DNA at least once.

FINDINGS

Nine of the 264 children were positive by virus culture or PCR, and subsequently seroreverted. Two of the nine tested virus-positive after they became antibody-negative. Six cases were virus-positive early in life and became negative thereafter, which is consistent with clearance of infection. The pattern was less clear in the other three. The nine cases had had their last virus test at age 16-101 months. All nine children had been bottlefed only. Eight had been delivered vaginally. The children had no HIV-related symptoms and received no anti-HIV treatments. Based on only those children who had two or more positive virological tests, we estimate that 2.7% (6/219) cleared or "tolerated" the virus.

INTERPRETATION

The detection of virus or viral DNA in "uninfected" children born to HIV-infected mothers was rare and was not associated with clinical disease or immunological abnormalities. The timing of samples will affect the documentation of clearance since, in uninfected children of HIV-positive mothers who cleared the virus, viraemia was intermittent. Current paediatric opinion is to inform parents of children who serorevert that the child is not HIV-infected.

The active site specificity of the Yersinia protein-tyrosine phosphatase

Yersinia protein-tyrosine phosphatase substrates have been synthesized employing an expedient methodology that incorporates phosphorylated non-amino acid residues into an active site-directed peptide. While the peptidic portion of these compounds serves an enzyme targeting role, the nonpeptidic component provides a critical assessment of the range of functionality that can be accommodated within the active site region. We have found that the Yersinia phosphatase hydrolyzes both L- and D-stereoisomers of phosphotyrosine in active site-directed peptides, with the former serving as a 10-fold more efficient substrate than the latter. In addition, this enzyme catalyzes the hydrolysis of a variety of aromatic and aliphatic phosphates. Indeed, a peptide bearing the achiral phosphotyrosine analog, phosphotyramine, is not only the most efficient substrate described in this study, it is also one of the most efficient substrates ever reported for the Yersinia phosphatase. Straight chain peptide-bound aliphatic phosphates of the general structure, (Glu)4-NH-(CH2)n-OPO3(2-) (n = 2-8), are also hydrolyzed, where the most efficient substrate contains seven methylene groups. Finally, a comparison of the substrate efficacy of the peptide-bound species with that of the corresponding non-peptidic analogs, reveals that the peptide component enhances kcat/Km by up to nearly 3 orders of magnitude.

Determining factors for the outcome of peripheral blood progenitor cells harvests

This is a pilot retrospective study to investigate the factors that may affect the collection of peripheral blood progenitor cells (PBPC). Sixty-nine PBPC harvests in 18 cancer patients (median age 39.5; 8 males and 10 females) were performed during marrow recovery after chemotherapy and hematopoietic growth factors. Median number of nucleated cells (MNC) collected were 13.3 (range 2.3-44.5) x 10(9) per session. Median CFU-GM was 362 colonies (range 63-1,720) per 500,000 MNC. Neither sex, body weight, diagnosis, nor the number of days into leukapheresis was significantly associated with MNC and CFU-GM. Older patients tend to have higher CFU-GM in the PBPC harvests (P = .0437). Higher WBC on the day of harvest is significantly associated with higher yield of MNC after leukapheresis (P < .0001). Patients without any evidence of disease have significantly higher yield of MNC than those having local/distant metastases with or without marrow involvement (P = .0302 and .0446). For patients with metastatic disease, those with bone marrow involvement tend to have higher CFU-GM than those without bone marrow involvement although the difference is not statistically significant (P = .0559). Those patients who have received only one, or three and more chemotherapy regimens have a higher yield of MNC than those who have only two previous chemotherapy regimens (P = .036 and .0324). The mechanism of PBPC mobilization is also discussed. In view of the limited patient number in this study, the results should be confirmed by larger studies.

[Increased production of nitric oxide in the immediate and late asthmatic responses in models of guinea pig experimental asthma]

Nitric oxide is produced in mammalian airways by constitutive and inducible nitric oxide synthase, and endogenous nitric oxide can be detected as exhaled gas. Patients with asthma have large numbers of airway epithelial cells and inflammatory cells that contain nitric oxide synthase, and nitric oxide levels in exhaled air are high during immediate asthmatic responses. To examine the dynamics of nitric oxide synthase in the tracheas of guinea pigs, cumulative dose-response studies of 5-HT were done on tracheal strips, in the presence or absence of arginine and its analogues. This assay indicated that relative the activity of nitric oxide synthase was greater 6 hr after the challenge than immediately after, which suggests that nitric oxide is involved in the pathogenesis of bronchial asthma attacks.

Use of polymerase chain reaction and quantitative antibody tests in children born to human immunodeficiency virus-1-infected mothers

The diagnosis of human immunodeficiency virus (HIV) infection in children born to HIV-infected mothers is complicated by the presence of passively acquired maternal antibodies, and exclusion of infection in these infants remains problematic. The use of genome detection by polymerase chain reaction (PCR) amplification and the quantification of anti-HIV-1 antibodies were examined as methods for early diagnosis. Blood samples were taken from 84 non-breast-fed infants of HIV-infected mothers in five Italian and Spanish centres, a subgroup of children enrolled in the European Collaborative Study (ECS) for whom clinical and immunological information has been documented from birth. Whole blood was added to glycigel cryopreservative, stored, and tested in the United Kingdom by a nested PCR method. Antibody to HIV-1 was detected and quantified by titration using a gelatin particle agglutination test. PCR sensitivity and specificity were assessed. Twenty-one of the 84 children tested were infected. The estimated PCR sensitivity ranged from 0% (95% CI 0-26%) on day 1, 57% (19-85) on day 7, to 63% (33-92) on day 30. The negative predictive value of PCR ranged from 85% (83-88) on day 0 to 98% (94-100) at 3 months of age. On average, the level of maternal antibody halved every 33 days (31-36.5) in uninfected children. Between 6 and 9 months of age, increases in antibody titres in infected children were not more informative than absolute levels. These findings suggest that antibody measurement may supplement genomic diagnosis and that this collection method provides an alternative to the use of dried blood spots.

The cyclic dilemma: organic, functional, and environmental interaction in a young teenager

This Grand Rounds considers an early-adolescent female who demonstrated a mixed clinical picture including rapid cycling of psychotic behavior. The case presents issues commonly faced in hospital practice and provides an example of the use of standardized instruments in assessment and monitoring treatment, as well as a discussion of issues germane to inpatient child and adolescent psychiatrists and related treatment team members.

The European Collaborative Study: clinical and immunological characteristics of HIV 1-infected pregnant women

OBJECTIVE

To describe the changing clinical and immunological characteristics and timing of diagnosis of HIV-infected pregnant women enrolled in the European Collaborative Study.

DESIGN

A prospective study of the mothers of children enrolled in the European Collaborative Study on children born to HIV-infected women.

SETTING

Twenty-one European centres in seven countries.

SUBJECTS

One thousand six hundred and ninety HIV-infected women and their 1754 deliveries.

RESULTS

The proportion of women in whom HIV infection had been diagnosed before pregnancy increased significantly over time, from 7% in 1984-1985 to 65% in 1994 (P < 0.001). The prevalence of breastfeeding, which was related to the timing of diagnosis, significantly declined over the study period. The mean CD4 count was 510 cells/mm3, and there was a significant decline in average CD4 count over the study period. Black women had a significantly lower CD4 count than white women. From survival analysis it is estimated that five years after delivery 14% of women will have died and 24% will have developed CDC stage IV disease.

CONCLUSIONS

Timing of diagnosis is of critical importance if mother-to-child transmission is to be reduced through avoidance of breastfeeding and zidovudine therapy and effective antenatal screening policies have become increasingly important. The rate of progression of maternal disease highlights the implications of HIV infection for their children, both infected and uninfected.

Implementation of the Patient Self-Determination Act in a community hospital

After extensive staff/community education, a New Jersey community hospital survey found good compliance with the Patient Self-Determination Act, but only 14.8 percent of patients had completed advance directives, and there was infrequent physician documentation.