Observation of New Isotopes in the Fragmentation of

Five previously unknown isotopes (^{182,183}Tm, ^{186,187}Yb, ^{190}Lu) were produced, separated, and identified for the first time at the Facility for Rare Isotope Beams (FRIB) using the Advanced Rare Isotope Separator (ARIS). The new isotopes were formed through the interaction of a ^{198}Pt beam with a carbon target at an energy of 186 MeV/u and with a primary beam power of 1.5 kW. Event-by-event particle identification of A, Z, and q for the reaction products was performed by combining measurements of the energy loss, time of flight, magnetic rigidity Bρ, and total kinetic energy. The ARIS separator has a novel two-stage design with high resolving power to strongly suppress contaminant beams. This successful new isotope search was performed less than one year after FRIB operations began and demonstrates the discovery potential of the facility which will ultimately provide 400 kW of primary beam power.

Persistence of HIV reservoir following successful haematopoietic stem cell transplant for juvenile myelomonocytic leukaemia in a child with perinatally acquired HIV.

This report describes a case of juvenile myelomonocytic leukaemia (JMML) on a background of both perinatally acquired HIV infection and congenital cytomegalovirus, and management of antiretroviral therapy during haematopoietic stem cell transplant. Peripheral blood HIV viral load remained below the lower limit of detection throughout and following transplant and is currently <20 RNA copies/mL. The child is currently in remission from JMML, but HIV DNA remains detectable despite myeloablative conditioning and sustained plasma HIV viral suppression.

No evidence of ongoing HIV replication or compartmentalization in tissues during combination antiretroviral therapy: Implications for HIV eradication.

HIV persistence during combination antiretroviral therapy (cART) is the principal obstacle to cure. Mechanisms responsible for persistence remain uncertain; infections may be maintained by persistence and clonal expansion of infected cells or by ongoing replication in anatomic locations with poor antiretroviral penetration. These mechanisms require different strategies for eradication, and determining their contributions to HIV persistence is essential. We used phylogenetic approaches to investigate, at the DNA level, HIV populations in blood, lymphoid, and other infected tissues obtained at colonoscopy or autopsy in individuals who were on cART for 8 to 16 years. We found no evidence of ongoing replication or compartmentalization of HIV; we did detect clonal expansion of infected cells that were present before cART. Long-term persistence, and not ongoing replication, is primarily responsible for maintaining HIV. HIV-infected cells present when cART is initiated represent the only identifiable source of persistence and is the appropriate focus for eradication.

Rapidly fatal Haemophilus influenzae serotype f sepsis in a healthy child.

A previously healthy 4-year-old child became acutely ill with vomiting and low-grade fever. The following day she suddenly became limp and unresponsive. She experienced acute septic shock and despite aggressive treatment died. Blood cultures grew ampicillin-resistant Haemophilus influenzae type f. There was no evidence of bacterial pneumonia or meningitis. To our knowledge, this represents the first case of fatal H. influenzae type f sepsis in a child without an identifiable focus or underlying predisposing condition. Despite the overwhelming success of the H. influenzae type b vaccine, physicians need to be aware of the potential for severe and fatal H. influenzae infections other than type b.

Longitudinal study of plasma cortisol and 17-hydroxyprogesterone in very-low-birth-weight infants during the first 16 weeks of life.

There are few published data on plasma cortisol and 17-hydroxyprogesterone (17-OHP) in very-low-birth-weight (VLBW) infants beyond the 1st week of life. We therefore measured plasma cortisol and 17-OHP longitudinally in 26 infants (median birth weight 930 g, median gestational age 28 weeks) from 1 to 16 postnatal weeks to document normative values. We also examined the effect of clinical state on plasma cortisol and 17-OHP levels. Median plasma cortisol decreased with postnatal age from 1 to 8 weeks (110 vs. 60 nmol/l; p = 0.0007) and with postconceptional age from 25 to 36 weeks (104 vs. 47 nmol/l; p = 0.002). Median plasma 17-OHP decreased with postnatal age from 1 to 16 weeks (17.0 vs. 7.1 nmol/l; p < 0.0005) and also with postconceptional age from 25 to 42 weeks (21.1 vs. 7.1 nmol/l; p < 0.0005). Plasma cortisol was not influenced by the clinical state. Median plasma 17-OHP was significantly higher for 'unwell' versus 'well' infants at 5-8 weeks postnatal age (23.0 vs. 12.5 nmol/l; p = 0.012) but not at other postnatal age intervals. These data provide information on adrenocortical function in VLBW infants during the first 4 months of life.

Optimization of dialysate flow and mass transfer during automated peritoneal dialysis.

The purpose of this study was to evaluate the effect of patient position on the mass transfer area coefficient (KoA) and to characterize drain/fill profiles in an effort to enhance efficiency of automated peritoneal dialysis. Over 100 exchanges were performed in 38 stable peritoneal dialysis patients to either determine the small solute KoA in the supine versus upright position or to characterize fill/drain profiles. The KoA for all solutes tested was significantly greater in the supine position compared with the upright position (P < 0.05). Fill profiles revealed the fill rate to be a function of fill height (P < 0.001) and patient position (supine > upright [P < 0.001]). Analysis of drain flow rate versus time revealed an initial segment of high outflow (350 +/- 89 mL/min) followed by an abrupt transition to a segment characterized by slow drainage (36 +/- 21 mL/min). The first segment of drain only took 5.6 +/- 2.3 minutes (42% of the total drain time); in that time, 83% +/- 10% of the dialysate was drained. The transition volume (volume of dialysate remaining at the time the transition occurs, excluding residual volume) correlated with body surface area (R = 0.52, P < 0.01). In conclusion, automated peritoneal dialysis treatment (including intermittent peritoneal dialysis, which may be done in the upright position) should be done in the supine position to optimize the KoA, and shortening drain time to include only the initial segment of high outflow will improve the efficiency and convenience of therapy.

Physiological aspects of disinfection resistance in Pseudomonas cepacia.

A Pseudomonas cepacia population was isolated which had reduced susceptibility to iodine and maintained resistance when subcultured several times in phosphate buffer. This population was also resistant to iodine after growth in a minimal medium containing glycerol but not glucose. Addition of cAMP to glucose-grown cells caused increased resistance to iodine. Iodine-resistant cultures also demonstrated reduced susceptibility to chlorination but not to heat or metals (Cu/Ag). The results indicate that halogen resistance can be expressed in varying degrees, dependent on the carbon source, and cAMP may promote this expression. Thus, a catabolite repression-like mechanism may cause resistant cultures grown in some media to become more sensitive to halogens.

Computerized method for validating laboratory reference ranges for triiodothyronine and thyroxin immunoassays.

We used a computer-based method to help validate the reference ranges of assays for triiodothyronine (T3) and thyroxin (T4). A retrospective search of a database of laboratory results for the previous six months identified all patients with apparent euthyroid status, as defined by methods independent of the immunoassay under review. A computer-generated reference group (CGR Group) of 2001 records had a gaussian distribution of T4 values and a reference range (mean +/- 2 SD) of 56-161 nmol/L, compared with the supplier's suggested range for euthyroid subjects (58-148 nmol/L) and an in-house range of 60-144 nmol/L for a group of 97 normal subjects. A similar CGR Group of 1902 records gave a reference range for T3 of 0.7-2.1 nmol/L (manufacturer's range 0.8-2.8; normal subjects 0.8-2.2). An attempt to devise a reference range for thyrotropin failed when we found that its concentration in the population of patients with normal values for thyroid hormones was distributed differently from that in the normal population. The method is intended to be used in addition to conventionally derived ranges based on results for healthy subjects. It allows the laboratory to conveniently verify the reference ranges for T3 and T4 assays at regular intervals by using very large samples with appropriate age, sex, and weight distribution, drawn from the population of patients' samples submitted for analysis.

Concentric and eccentric quadriceps torque in pre-adolescent males.

The purpose of this study was to evaluate the applicability of using the Kin Com (Chattecx Corp., Chattanooga, TN) isokinetic machine to measure concentric and eccentric quadriceps torque in a group of 12 healthy male volunteers aged 10-12 years. Each individual was tested by an experienced physiotherapist using a 60 degree per second velocity mode according to our standardized protocol. Average and peak torque values for concentric and eccentric contractions of the quadriceps were recorded; based upon the best of three maximum effort trials on each lower extremity. Retesting was performed on a randomly selected sub-group in an identical manner two weeks later. Our results showed no statistically significant difference between the original and retest values using the method error of repeated measurements and paired t-test analyses. Eccentric peak torque was greater on average than concentric. This was significant with p-values of 0.01 for the non-dominant quadriceps and 0.002 for the dominant side (paired t-test). There was no significant difference between the dominant and non-dominant sides. In conclusion, eccentric muscle testing has been reliably quantitated for the first time in children. This study has shown a practical and reproducible method of quantitative muscle strength assessment.

Enumeration of Enterobacter cloacae after chloramine exposure.

Growth of Enterobacter cloacae on various media was compared after disinfection. This was done to examine the effects of monochloramine and chlorine on the enumeration of coliforms. The media used were TLY (nonselective; 5.5% tryptic soy broth, 0.3% yeast extract, 1.0% lactose, and 1.5% Bacto-Agar), m-T7 (selective; developed to recover injured coliforms), m-Endo (selective; contains sodium sulfite), TLYS (TLY with sodium sulfite), and m-T7S (m-T7 with sodium sulfite). Sodium sulfite in any medium improved the recovery of chloramine-treated E. cloacae. However, sodium sulfite in TLYS and m-T7S did not significantly improve the detection of chlorine-treated E. cloacae, and m-Endo was the least effective medium for recovering chlorinated bacteria. Differences in recovery of chlorine- and chloramine-treated E. cloacae are consistent with mechanistic differences between the disinfectants.