92 Using physical parameters of bovine zygotes to predict invitro development success

The objective of this study was to determine if physical parameters of bovine zygotes are correlated with invitro development success. We examined the relationship between a zygote's outer diameter (OD), cell area, and zona pellucida (ZP) thickness on blastocyst development and blastomere number. Bovine cumulus-oocyte complexes, from abattoir-derived ovaries, were matured in tissue culture medium 199-based maturation medium for 21-23h. Invitro fertilisation was performed with frozen thawed semen containing a pool of 4 Holstein bulls. After incubation with sperm for 16-18h, presumptive zygotes (n=875) were denuded and placed in 5µL droplets of synthetic oviductal fluid-bovine embryo 1 medium (SOF-BE1) under oil to be individually photographed using an inverted scope with a digital camera. Zygotes were then group-cultured in 50µL of synthetic oviductal fluid-BE1 droplets in a polyester micromesh to identify individuals. Development to the blastocyst stage was recorded on Day 7 and Day 8 of culture, and Day 8 embryos were fixed and stained with Hoechst 33342 (n=87). ImageJ was used to measure the OD, area, and ZP from images. Data were analysed with a logistic regression using the lme4 package in R with Day 7 or Day 8 blastocyst development as the response; OD, area, and ZP as predictors; and study replicate (n=11) and culture droplet as random effects. Residual estimates of area and ZP calculated from OD were used to account for collinearity. Average OD was 151.2µm, ranging 130.4-171.6µm. Average ZP was 11.8µm, ranging 7.2-17.5µm. Area averaged 9856.7µm2, ranging from 6421.9 to 13 814.8 µm2. There was a tendency for an effect of OD on probability of development on Day 8 (P=0.08) but not Day 7. There was an effect of ZP on the probability of development on Day 8 (P=0.04) but not Day 7. Blastocyst rates on Day 8 for zygotes with ZP <11.8µm were 24.3%, whereas zygotes with ZP >11.8µm were 21.7%. There was an interaction (P<0.05) between OD and ZP thickness on Day 7 and Day 8. Estimated probability of development of zygotes with ZP <10.7µm and OD <146.9µm averaged 28.5%, whereas those with ZP >12.7µm and OD >155.8µm averaged 43.3%. The observed blastocyst rates for these two groups were 26.2% and 25%, respectively. Zygotes with OD between 146.9-155.8µm and ZP between 10.7-12.7µm had an estimated development probability of 22.2%. The obtained Day 8 blastocyst rate for this group was 22.5%. Area did not affect probability of development, but was positively correlated with total blastomere number at Day 8 (P=0.01; marginal R2=0.09). The observed interaction between ZP thickness and OD may be indicative of an optimum ooplasm area before maturation or fertilisation that may enhance development. Area assessment after fertilisation is not correlated with development success. In addition, these data in comparison with our previous data generated in parthenogenetic embryos indicate that artificial activation of oocytes is not an ideal model in place of IVF for studying development. We continue to demonstrate that physical parameters of zygotes may have potential as a noninvasive, objective selection tool of embryos.

Effect of caffeinated gum on a battery of rugby-specific tests in trained university-standard male rugby union players

Background

Caffeine has been shown to enhance strength, power and endurance, characteristics that underpin performance in rugby. Caffeinated gum has attracted interest as a novel vehicle for delivering caffeine, because absorption of caffeine from gum is quick. Rapid absorption of caffeine may be useful during rugby matches when there is limited time for supplementation such as at half-time or when substitutes enter play. The purpose of this study was to determine whether a low dose of caffeine in gum improves performance in a battery of rugby-specific tests.

Methods

In a double-blind, randomized, placebo-controlled, crossover design, 17 male university-standard rugby players (mass: 85.6 ± 6.3 kg; height: 179.4 ± 6.2 cm; age: 20.4 ± 1.2 years) chewed caffeinated gum (200 mg caffeine) or a placebo gum on two occasions separated by a week. After a standardized warm-up, gum was chewed for 5 min. Subsequently, participants performed three countermovement jumps, followed by an Illinois agility test, 6 × 30 m repeated sprints, and the Yo-Yo IR-2 test; each test was separated by short rest periods.

Results

Caffeinated gum enhanced countermovement jump by 3.6% (caffeine: 43.7 ± 7.6 cm vs. placebo: 42.2 ± 6.2 cm; d = 0.22, 95% CI [0.006, 0.432]; p = 0.044). There was a greater resistance to fatigue during the 6 × 30 m repeated sprint test (fatigue index caffeine: 102.2 ± 0.9% vs. placebo: 103.3 ± 1.2%; d = 1.03, 95% CI [0.430, 1.613]; p = 0.001), and performance on the Yo-Yo IR2 was improved by 14.5% (caffeine: 426 ± 105 m, placebo: 372 ± 91 m; d = 0.55, 95% CI [0.130, 0.957]; p = 0.010). Caffeine gum had no significant effect on the Illinois agility test (caffeine 16.22 ± 1.08 s vs. placebo 15.88 ± 1.09 s; d = − 0.31, 95% CI [− 0.855, 0.240]; p = 0.271).

Conclusions

In university-standard rugby players, a low dose of caffeine (200 mg) supplied in chewing gum enhanced performance on the Yo-Yo IR-2 test and the countermovement jump test and reduced fatigue index during repeated sprints. These improvements in a battery of rugby-specific tests may transfer to enhanced performance in rugby matches.

158 Predicting embryo development success with physical parameters of oocytes

There is a continual search for reliable, noninvasive methods of selecting viable oocytes and embryos. Previous studies have indicated that the physical size of oocytes may reflect their developmental potential. The objective of this study was to observe the correlation between an oocyte’s diameter [including zona pellucida (ZP), cell area, and ZP thickness] and its ability to develop. Bovine cumulus-oocyte complexes were collected from abattoir-derived ovaries and incubated for 24h in TCM-199-based maturation medium. The cumulus-oocyte complexes were denuded by vortexing with hyaluronidase, and mature oocytes were selected based on presence of a visible polar body. Selected oocytes were artificially activated by incubating in 5 μM ionomycin for 5min followed by incubation in 2mM 6-DMAP for 3h (n=723). After activation, oocytes were placed in individual 5-μL culture droplets under oil and photographed using an inverted scope with digital camera. Oocytes were then group cultured in 50-μL droplets in a polyester micromesh for identification of individual oocytes. Development to the blastocyst stage was noted on Days 7 and 8 of culture. ImageJ was used to measure diameter, area, and ZP thickness from images. A logistic regression using the lme4 package in R was run with Day 7 or 8 blastocyst development as the response; diameter, area, and ZP thickness as predictors; and replicate and culture droplet as random effects. The residual estimates of area and ZP thickness from diameter were used to account for correlation between predictors. Only significant interactions were kept in the model. The ZP thickness ranged from 6.1 to 17.7μm with a mean of 12μm. There was a significant correlation between diameter and ZP thickness (P<0.01, R2=0.12) with a correlation coefficient of 0.35. Oocyte diameter had a significant effect on subsequent blastocyst development on Day 7 (P<0.01) and Day 8 (P<0.01), with larger oocytes more likely to develop on both days. Oocytes were also grouped into quantiles by diameter. Larger groups were more likely to develop to the blastocyst stage on Day 7 (P<0.001) and Day 8 (P<0.001). Blastocyst rate on Day 8 for oocytes with diameters <149.5μm was 24.2%, whereas blastocyst rate on Day 8 for those with diameters=159μm was 41.2%. In addition, ZP thickness also had an effect: oocytes with thinner ZP were more likely to develop to the blastocyst stage on Day 7 (P<0.001) and Day 8 (P<0.001). Blastocyst rate for oocytes with a ZP thickness <11μm was 37%, whereas the rate for those with a ZP thickness of 12.9μm was 27.6%. Area did not have an effect on blastocyst formation on Day 7 or 8 (P=0.21). Here we have demonstrated that the oocyte diameter, including the ZP and ZP thickness, affects its probability of development. Larger oocytes and those with thinner ZP are more likely to develop to the blastocyst stage. Differences in the size of the perivitelline space could explain why diameter had a significant effect on development and area did not. Further studies will focus on determining the relationship between these physical parameters of oocytes and embryo quality.

Insulin kinetics and the Neonatal Intensive Care Insulin-Nutrition-Glucose (NICING) model

BACKGROUND

Models of human glucose-insulin physiology have been developed for a range of uses, with similarly different levels of complexity and accuracy. STAR (Stochastic Targeted) is a model-based approach to glycaemic control. Elevated blood glucose concentrations (hyperglycaemia) are a common complication of stress and prematurity in very premature infants, and have been associated with worsened outcomes and higher mortality. This research identifies and validates the model parameters for model-based glycaemic control in neonatal intensive care.

METHODS

C-peptide, plasma insulin, and BG from a cohort of 41 extremely pre-term (median age 27.2 [26.2-28.7] weeks) and very low birth weight infants (median birth weight 839 [735-1000] g) are used alongside C-peptide kinetic models to identify model parameters associated with insulin kinetics in the NICING (Neonatal Intensive Care Insulin-Nutrition-Glucose) model. A literature analysis is used to determine models of kidney clearance and body fluid compartment volumes. The full, final NICING model is validated by fitting the model to a cohort of 160 glucose, insulin, and nutrition data records from extremely premature infants from two different NICUs (neonatal intensive care units).

RESULTS

Six model parameters related to insulin kinetics were identified. The resulting NICING model is more physiologically descriptive than prior model iterations, including clearance pathways of insulin via the liver and kidney, rather than a lumped parameter. In addition, insulin diffusion between plasma and interstitial spaces is evaluated, with differences in distribution volume taken into consideration for each of these spaces. The NICING model was shown to fit clinical data well, with a low model fit error similar to that of previous model iterations.

CONCLUSIONS

Insulin kinetic parameters have been identified, and the NICING model is presented for glycaemic control neonatal intensive care. The resulting NICING model is more complex and physiologically relevant, with no loss in bedside-identifiability or ability to capture and predict metabolic dynamics.

Impact of bread making on fructan chain integrity and effect of fructan enriched breads on breath hydrogen, satiety, energy intake, PYY and ghrelin

Recently, there has been considerable interest in the satiety inducing properties of inulin type fructans (ITF) as a tool for weight management. As a staple food, breads provide an excellent vehicle for ITF supplementation however the integrity of the ITF chains and properties upon bread making need to be assessed. Breads enriched with 12% fructooligosaccharides (FOS) and 12% inulin were baked and the degree of polymerisation of fructans extracted from the breads were compared to those of pure compounds. An acute feeding study with a single blind cross-over design was conducted with 11 participants to investigate the effect of ITF enriched breads on breath hydrogen, self-reported satiety levels, active ghrelin, total PYY and energy intake. Size exclusion chromatography indicated that little or no depolymerisation of inulin occurred during bread making, however, there was evidence of modest FOS depolymerisation. Additionally, ITF enriched breads resulted in increased concentrations of exhaled hydrogen although statistical significance was reached only for the inulin enriched bread (p = 0.001). There were no significant differences between bread types in reported satiety (p = 0.129), plasma active ghrelin (p = 0.684), plasma PYY (p = 0.793) and energy intake (p = 0.240). These preliminary results indicate that inulin enriched bread may be a suitable staple food to increase ITF intake. Longer intervention trials are required to assess the impact of inulin enriched breads on energy intake and body weight.

A critical review of the effectiveness of rodent pharmaceutical carcinogenesis testing in predicting for human risk

The pharmaceutical industry and regulatory agency toxicology testing paradigms in the United States currently appear successful, in part because of the continuously increasing life expectancy and the declining age-adjusted cancer rates in the United States. Although drugs likely have a minimal impact on the population statistics for cancer rates, pharmaceutical pathologists and toxicologists must focus on the individual risk for pharmaceutical carcinogenesis. As our understanding of carcinogenesis increases exponentially, and after hundreds if not thousands of rodent cancer tests, significant improvement in the precision of human pharmaceutical carcinogenesis hazard identification should now be possible and would enable a reduction in the substantial false-negative and false positive-rates reported herein. The appropriate use of acute, subchronic, chronic, and special toxicology tests to identify the major associated cancer risk factors, specifically, hormonal modulation, immunosuppression, genetic toxicity, and chronic toxicity, can be recognized through this review of pharmaceutical carcinogens. Significant opportunities exist for improving the effectiveness and efficiency of the current cancer risk assessment paradigm.

Dynamic model for predicting death within 12 months in patients with primary or post-polycythemia vera/essential thrombocythemia myelofibrosis

PURPOSE

Current prognostic tools in myelofibrosis (MF) fail to identify patients at the highest risk of death and are limited by their applicability only to the time of diagnosis. We aimed to define an accelerated phase (AP) in MF by characterizing disease features that can identify patients with median overall survival of <or= 12 months at any time in the disease course.

PATIENTS AND METHODS

Baseline characteristics of 370 consecutive patients with MF from a single center were analyzed to identify features associated with a median overall survival of <or= 12 months. These putative AP features were then validated by following the course of chronic-phase patients (no AP features at baseline) until the development of one or more AP features and determining their subsequent survival.

RESULTS

The following three characteristics were associated with poor survival at baseline and were selected as putative AP features: blasts in blood or bone marrow >or= 10%, platelets less than 50 x 10(9)/L, and chromosome 17 aberrations (median overall survival, 10, 12, and 5 months, respectively). In the validation phase, chronic-phase patients who developed AP features during follow-up were found to have short subsequent survival times (median overall survival, 12, 15, and 6 months, respectively). AP was a necessary step in the progression to blast phase, with leukemic transformation being exceedingly rare (3% risk at 10 years) in patients who remained persistently in chronic phase.

CONCLUSION

Blood or bone marrow blasts >or= 10%, platelets less than 50 x 10(9)/L, and chromosome 17 aberrations defined AP in patients with MF. Patients in AP should be candidates for intensive therapeutic interventions.

Systemic mastocytosis in association with chronic lymphocytic leukemia: A rare diagnosis

Systemic mastocytosis may be primary or be associated with other hematological malignancies, most commonly myeloid neoplasms. In contrast, the association of systemic mastocytosis with lymphoid neoplasms is comparatively rare, and in the absence of appropriate clinical vigilance the diagnosis may be missed. We report a case of aggressive systemic mastocytosis associated with chronic lymphocytic leukemia (SM-CLL), placing particular emphasis on the investigational algorithm used in establishing this diagnosis, and discussing key clinical considerations in the initiation of therapy.

Cytological studies of meiotic recombination in human males

We combined immunostaining and fluorescence in situ hybridization (FISH) methodology to directly examine meiotic exchanges in over 2,000 pachytene stage spermatocytes from 25 individuals. Our results indicate that, on average, there are about 50 exchanges per cell and that, with the exception of the acrocentric chromosomes, all chromosome arms harbor at least one exchange. We also identified significant among-individual variation in the mean number of exchanges, with an approximate 20% difference between individuals with "low" and those with "high" exchange frequencies.

Early results of a chemoimmunotherapy regimen of fludarabine, cyclophosphamide, and rituximab as initial therapy for chronic lymphocytic leukemia

PURPOSE

Fludarabine and cyclophosphamide (FC), which are active in treatment of chronic lymphocytic leukemia (CLL), are synergistic with the monoclonal antibody rituximab in vitro in lymphoma cell lines. A chemoimmunotherapy program consisting of fludarabine, cyclophosphamide, and rituximab (FCR) was developed with the goal of increasing the complete remission (CR) rate in previously untreated CLL patients to >/= 50%.

PATIENTS AND METHODS

We conducted a single-arm study of FCR as initial therapy in 224 patients with progressive or advanced CLL. Flow cytometry was used to measure residual disease. Results and safety were compared with a previous regimen using FC.

RESULTS

The median age was 58 years; 75 patients (33%) had Rai stage III to IV disease. The CR rate was 70% (95% CI, 63% to 76%), the nodular partial remission rate was 10%, and the partial remission rate was 15%, for an overall response rate of 95% (95% CI, 92% to 98%). Two thirds of patients evaluated with flow cytometry had less than 1% CD5- and CD19-coexpressing cells in bone marrow after therapy. Grade 3 to 4 neutropenia occurred during 52% of courses; major and minor infections were seen in 2.6% and 10% of courses, respectively. One third of the 224 patients had >/= one episode of infection, and 10% had a fever of unknown origin.

CONCLUSION

FCR produced a high CR rate in previously untreated CLL. Most patients had no detectable disease on flow cytometry at the end of therapy. Time to treatment failure analysis showed that 69% of patients were projected to be failure free at 4 years (95% CI, 57% to 81%).

Chronic Physical Exercise Reduces Anxiety-Like Behavior In Rats

While many individuals with anxiety disorders receive drug therapy, many do not respond or adversely respond to drugs. An alternative treatment, exercise, has been shown to relieve negative feelings and induce positive shifts in mood. The purpose of this study was to establish an animal model to specifically test the effects of chronic physical exercise on anxiety-related behaviors. Thirty-two male Sprague Dawley rats were divided into two groups: runners (R) and nonrunners (NR). Runners ran on a treadmill for 45 minutes a day, five days a week, for ten weeks at a moderate intensity. Nonrunners remained in their cages in the treadmill room during the running period and were handled for an equal amount of time. After ten weeks of training, two behavioral tests were administered including the elevated plus maze and open field tests. Results comparing R and NR showed higher responses by R in percent open arm time and center square time during the elevated plus maze test, as well as in number of entries into the center, number of rears, and lower fecal boli count during the open field test, p < 0.05. In addition, there were no differences in total activity levels between groups as indicated by similar closed arm entries in the elevated plus maze test and total lines crossed in the open field test. These results indicate that treadmill training reduces anxiety-like behaviors in two animal tests of anxiety, without a significant change in total activity levels. These data are in support of treadmill training as a model to test the anxiolytic effects of exercise.

Treatment of chronic lymphocytic leukemia with alemtuzumab: a review for nurses

PURPOSE/OBJECTIVES

To review the use of the monoclonal antibody alemtuzumab in patients with advanced refractory B cell chronic lymphocytic leukemia (B-CLL) and nursing management during treatment.

DATA SOURCES

Published articles, abstracts, book chapters, Web sites, and training material.

DATA SYNTHESIS

Alemtuzumab can achieve disease remission in patients with chemorefractory B-CLL; however, management of high-risk patients presents certain challenges. Infusion-related events can be minimized by stepwise administration and appropriate prophylaxis. Cytopenia can be minimized by drug postponement and cytokine support or red blood cell or platelet transfusions. Patients also are at risk for infection because of lymphopenia, and anti-infective prophylaxis is mandatory at initiation of therapy until at least two months post-treatment.

CONCLUSIONS

With satisfactory supportive measures in place, patients with chemorefractory B-CLL can experience the benefits of alemtuzumab therapy without excessive toxicity.

IMPLICATIONS FOR NURSING

Nurses should be familiar with treatment and prophylactic protocols, be ready to offer supportive therapy to control side effects, and invest time in patient education.

Radiological stenting provides effective palliation in malignant central venous obstruction

Malignant superior vena caval obstruction (SVCO) due to lung cancer carries a poor prognosis and response to palliative radiotherapy is variable. Eighteen patients presenting with the appearance of malignant SVCO (thirteen due to primary bronchial tumours) in a four year period from June 1995 to July 1999 underwent venography with a view to placement of an expanding metal stent under radiological control. Fourteen patients were male and four female with a mean age at presentation of 65 years (range 44-84 years). At venography only three patients had isolated SVC stenosis, fivealso had brachiocephalic, internal jugular or subclavian vein stenoses and one had an isolated right brachiocephalic stenosis. Venography demonstrated thrombus in eight of the remaining patients, seven in association with stenosis. In one patient stenosis of the SVC was thought to be due to radiation fibrosis as no mass was visible. All underwent Seldinger catheterization of the great veins via a right femoral puncture with deployment of the stent over a guide wire. Balloon angioplasty was performed prior to stent placement in eight patients. The eight patients with thrombus underwent thrombolysis using rt-PA (recombinant tissue-type plasminogen activator) with subsequent stent placement in seven. Radiological relief of obstruction with abolition of collateral flow was observed in all cases. One patient required further stenting for recurrent obstruction after 160 days of palliation. The median duration of palliation after stenting was 87 days. No procedure-related morbidity was observed. Thrombolysis was of value in patients with occlusive thrombus, either in isolation or complicating a malignant stricture, where radiotherapy may not have been effective. Radiological stenting is a safe technique which offers rapid palliation of SVCO.

Metacognitive remediation in adult ADHD. Treating executive function deficits via executive functions

The neuropathology underlying ADHD most consistently points to dysfunction in corticostriatal pathways--leading to inactivation, or insufficient engagement, of frontal and prefrontal lobes. By implication there may be functional disconnection between the anterior and posterior higher cortical regions, instead of a fixed dysfunction in either one. Given this premise, reconnection of these systems via cognitive interventions constitutes a logical remedial approach in the treatment of ADHD, which this paper introduces. In particular, a hybrid model is developed which proposes integration of existing psychodynamic, cognitive, and neuropsychological interventions. An organizing theme is expansion of metacognitive understanding through these procedures, powerfully exemplified via use of metaphor in clinical vignettes.

Biochemical, biophysical, and functional characterization of bacterially expressed and refolded receptor binding domain of Plasmodium vivax duffy-binding protein

Invasion of erythrocytes by malaria parasites is mediated by specific molecular interactions. Plasmodium vivax is completely dependent on interaction with the Duffy blood group antigen to invade human erythrocytes. The P. vivax Duffy-binding protein, which binds the Duffy antigen during invasion, belongs to a family of erythrocyte-binding proteins that also includes Plasmodium falciparum sialic acid binding protein and Plasmodium knowlesi Duffy binding protein. The receptor binding domains of these proteins lie in a conserved, N-terminal, cysteine-rich region, region II, found in each of these proteins. Here, we have expressed P. vivax region II (PvRII), the P. vivax Duffy binding domain, in Escherichia coli. Recombinant PvRII is incorrectly folded and accumulates in inclusion bodies. We have developed methods to refold and purify recombinant PvRII in its functional conformation. Biochemical, biophysical, and functional characterization confirms that recombinant PvRII is pure, homogeneous, and functionally active in that it binds Duffy-positive human erythrocytes with specificity. Refolded PvRII is highly immunogenic and elicits high titer antibodies that can inhibit binding of P. vivax Duffy-binding protein to erythrocytes, providing support for its development as a vaccine candidate for P. vivax malaria. Development of methods to produce functionally active recombinant PvRII is an important step for structural studies as well as vaccine development.

Generation of retroviral packaging and producer cell lines for large-scale vector production and clinical application: improved safety and high titer

For many applications, human clinical therapies using retroviral vectors still require many technological improvements in key areas of vector design and production. These improvements include higher unprocessed manufacturing titers, complement-resistant vectors, and minimized potential to generate replication-competent retrovirus (RCR). To address these issues, we have developed a panel of human packaging cell lines (PCLs) with reduced homology between retroviral vector and packaging components. These reduced-homology PCLs allowed for the use of a novel high multiplicity of transduction ("high m.o. t.") method to introduce multiple copies of provector within vector-producing cell lines (VPCLs), resulting in high-titer vector without the generation of RCR. In a distinct approach to increase vector yields, we integrated manufacturing parameters into screening strategies and clone selection for large-scale vector production. Collectively, these improvements have resulted in the development of diverse VPCLs with unprocessed titers exceeding 2 x 10(7) CFU/ml. Using this technology, human Factor VIII VPCLs yielding titers as high as 2 x 10(8) CFU/ml unprocessed supernatant were generated. These cell lines produce complement-resistant vector particles (N. J. DePolo et al., J. Virol. 73: 6708-6714, 1999) and provide the basis for an ongoing Factor VIII gene therapy clinical trial.

Patterns of meiotic recombination on the long arm of human chromosome 21

In this study we quantify the features of meiotic recombination on the long arm of human chromosome 21. We constructed a 67. 3-centimorgan (cM) high-resolution, comprehensive, and accurate genetic linkage map of chromosome 21q using 187 highly polymorphic markers covering almost the entire long arm; 46 loci, consisting of mutually recombining marker sets, were ordered with greater than 1000:1 odds and with average interlocus distance of 1.46 cM. These markers were used to accurately identify all exchanges in 186 female and 160 male meioses and to show (1) significant excess of recombination in female versus male meioses, (2) an overall decline in female:male recombination between the centromere and the telomere, (3) greater positive chiasma interference in male than in female meioses, and (4) lack of correlation between exchange frequency and parental age. By comparing the genetic map with the 21q sequence map, we show a general trend of increasing male, but near-constant female, recombination versus physical distance across 21q, explaining the gender-specific recombination effect. The recombination rate varies considerably between genders across 21q but is the greatest (eightfold) in the pericentromeric region, with a rate of approximately 250 kb/cM in females and approximately 2125 kb/cM in males. We used information on the locations of all exchanges to construct an empirical map function that confirms the statistical findings of positive interference. These analyses reveal that occurrence of recombination on 21q is not only gender-specific but also region-specific and that recombination suppression at the centromere is not universal. We also find evidence that male exchange location is highly correlated with gene density.

Heme binding and polymerization by Plasmodium falciparum histidine rich protein II: influence of pH on activity and conformation

The histidine rich protein II (HRPII) from Plasmodium falciparum has been implicated as a heme polymerase which detoxifies free heme by its polymerization to inactive hemozoin. Histidine-iron center coordination is the dominant mechanism of interaction between the amino acid and heme. The protein also contains aspartate allowing for ionic/coordination interactions between the carboxylate side chain and the heme metal center. The pH profile of heme binding and polymerization shows the possibility of these two types of binding sites being differentiated by pH. Circular dichroism studies of the protein show that pH and heme binding cause a change in conformation above pH 6 implying the involvement of His-His+ transitions. Heme binding at pHs above 6 perturbs HRPII conformation, causing an increase in helicity.

Two sequence-ready contigs spanning the two copies of a 200-kb duplication on human 21q: partial sequence and polymorphisms

Physical mapping across a duplication can be a tour de force if the region is larger than the size of a bacterial clone. This was the case of the 170- to 275-kb duplication present on the long arm of chromosome 21 in normal human at 21q11.1 (proximal region) and at 21q22.1 (distal region), which we described previously. We have constructed sequence-ready contigs of the two copies of the duplication of which all the clones are genuine representatives of one copy or the other. This required the identification of four duplicon polymorphisms that are copy-specific and nonallelic variations in the sequence of the STSs. Thirteen STSs were mapped inside the duplicated region and 5 outside but close to the boundaries. Among these STSs 10 were end clones from YACs, PACs, or cosmids, and the average interval between two markers in the duplicated region was 16 kb. Eight PACs and cosmids showing minimal overlaps were selected in both copies of the duplication. Comparative sequence analysis along the duplication showed three single-basepair changes between the two copies over 659 bp sequenced (4 STSs), suggesting that the duplication is recent (less than 4 mya). Two CpG islands were located in the duplication, but no genes were identified after a 36-kb cosmid from the proximal copy of the duplication was sequenced. The homology of this chromosome 21 duplicated region with the pericentromeric regions of chromosomes 13, 2, and 18 suggests that the mechanism involved is probably similar to pericentromeric-directed mechanisms described in interchromosomal duplications.

Clearance of morphine in postoperative infants during intravenous infusion: the influence of age and surgery

We analyzed morphine clearance values in infants receiving the drug by continuous i.v. infusion for analgesia after surgery, because we found lower steady-state morphine concentrations than we expected from our previous studies. Infants received morphine after a loading dose of 0.05 mg/kg and continuous infusion calculated to reach a steady-state concentration of 20 ng/mL. Blood was sampled twice on Postoperative Day 1 at times separated by at least 2 h, and morphine and morphine-6-glucuronide (M-6-G) concentrations were determined by high-performance liquid chromatography. Clearance of morphine was calculated as infusion rate divided by the steady-state morphine concentration. Morphine given to 26 infants by continuous i.v. infusion after major noncardiac surgery has rapidly increasing clearance values, from a median value of 9.2 mL x min(-1) x kg(-1) in infants 1-7 days old, 25.3 in infants 31-90 days old, and 31.0 in infants 91-180 days old to 48.9 in infants 180-380 days old. Adult clearance values are reached by 1 mo of age, more quickly than in infants of the same age previously studied who received morphine after cardiac surgeries. M-6-G was measured in all infants. The ratio of M-6-G to morphine concentrations was 1.9-2.1 in these infants, which is lower than ratios reported in older infants or adults by others, but higher than those reported in newborns. Infants with normal cardiovascular systems undergoing surgery clear morphine more efficiently than infants of the same age undergoing cardiac surgery.

IMPLICATIONS

Morphine removal from the body is slow in newborns but increases to reach adult values in the first months of life. Calculating the clearance of morphine from blood samples drawn during continuous i.v. infusions after surgery shows that this maturation occurs more quickly in infants undergoing noncardiac surgery (by 1-3 mo of age) than in those receiving morphine after cardiac surgery (by 6-12 mo of age).

Pain scores in infants: a modified infant pain scale versus visual analogue

This study describes an observational system (modified infant pain scale, MIPS) with elements from a previously published observational scale and from assessments of video-recorded infant facial expressions. It was designed to allow rapid and repeated assessments of pain in infants after brief training by an observer without pediatric experience. Forty healthy term infants (17 +/- 7 weeks) undergoing elective surgery had simultaneous independent assessment of pain using two scales: a naive observer used the MIPS and an experienced pediatric nurse used a 10-cm unmarked horizontal visual analogue scale (VAS). This validation of the MIPS included its division during analysis into partial (P-MIPS, without data on sleep or vital signs) and total scores. Infants had a broad range of MIPS scores, and the two scales categorized infants as "comfortable" or "not comfortable" with a high degree of concordance. The MIPS was easily incorporated into an infant's physical examination. We recommend its use for two-point clinical pain assessment.

A study of the prevalence of Helicobacter pylori infection and other markers of upper gastrointestinal tract disease in patients with rosacea

OBJECTIVE

Recent reports have suggested that patients with rosacea, a chronic inflammatory skin disorder of unknown etiology, have an increased prevalence of Helicobacter pylori infection. However, no causal relation has been identified. This study was designed to determine the prevalence of H. pylori infection and upper gastrointestinal symptoms in rosacea patients and in subjects without chronic skin disorders.

METHODS

Forty-five patients with rosacea and 43 healthy subjects underwent serological testing for H. pylori infection. Demographics, gastrointestinal symptoms, and medication use were recorded using a structured questionnaire.

RESULTS

There was no significant difference in the seroprevalence of H. pylori infection between rosacea patients and healthy subjects (26.7% vs 34.9%; p = 0.40). Significantly more patients with rosacea complained of indigestion (66.7% vs 32.6%; p = 0.001) and used antacids (60% vs 32.6; p = 0.01). There was no significant difference in the prevalence of H. pylori infection between symptomatic and asymptomatic rosacea patients, or in those using antacids. There were no differences in the frequency of heartburn, history of peptic ulcer disease, family history of peptic ulcer disease, use of H2-receptor antagonists, or use of nonsteroidal antiinflammatory drugs.

CONCLUSIONS

Patients with rosacea have similar rates of H. pylori infection as healthy subjects. Rosacea patients complain significantly more frequently of "indigestion" and use more antacids unrelated to H. pylori infection.

Cloning of a novel homeobox-containing gene, PKNOX1, and mapping to human chromosome 21q22.3

To contribute to the development of the transcript map of human chromosome 21 and to the understanding of the pathogenesis of Down syndrome, we have used exon trapping to identify portions of genes from pools of HC21-specific cosmids. More than 550 potential exons have been isolated to date. One such trapped exon, hmc37a09 (GenBank Accession No. X88106), was identical to a region of a human EST, L12425 (GenBank Accession No. D31072). Its predicted amino acid sequence was homologous to the homeodomain region of homeobox-containing genes. Using the trapped sequence and the EST as probes to screen human fetal brain and kidney cDNA libraries, we have cloned the corresponding full-length cDNA. This novel gene encodes a homeodomain-containing polypeptide of 436 amino acids. The most closely related sequence is that of the mouse Meis1, a PBX-like homeobox gene. The homeodomain of the novel gene is closely related to those of the mammalian PBX family and the plant Knotted1 family (involved in plant development). This gene is named PKNOX1 by the Human Nomenclature Committee. By PCR amplification, hybridization, and genetic linkage analysis using a (GT)n polymorphism in the 3'UTR, we have precisely localized PKNOX1 to chromosome 21q22.3 between markers D21S212 and D21S25 on YAC350F7. PKNOX1 is expressed in many human tissues tested by Northern blot analysis. The involvement of the PKNOX1 gene in Down syndrome and/or monogenic disorders associated with dysfunction of this gene is presently unknown. Targeted disruption of the PKNOX1 homolog in mice will enhance our understanding of its biological function in normal mammalian development.

Antigen presentation in retroviral vector-mediated gene transfer in vivo

We have examined mechanisms involved in gene transfer, protein expression, and antigen presentation after direct administration of retroviral vectors using a variety of antigen systems. We have identified transduced infiltrating cells at the injection site, and the majority of the infiltrating cells were of the monocyte/macrophage lineage. We found that the splenic dendritic cell fraction contained proviral DNA, expressed antigenic proteins, and was able to present antigens efficiently to the immune system. Furthermore, the dendritic cell fractions from retroviral vector-immunized mice were able to prime naive T cells in vitro, and adoptive transfer of in vitro-transduced dendritic cell fractions elicited antigen-specific cytotoxic T lymphocytes. These data suggest a role for dendritic cells in induction of immune responses elicited by retroviral vector-mediated gene transfer.

Transthyretin amyloidosis: a new mutation associated with dementia

Familial transthyretin (TTR) amyloidosis commonly presents with peripheral neuropathy and involvement of visceral organs. In contrast, signs of central nervous system (CNS) involvement are exceptional. We report that members of a kindred affected by a slowly progressive dementia, seizures, ataxia, hemiparesis, and decreased vision without neuropathy have TTR amyloid deposits in the leptomeninges, the brain parenchyma, and the eye. This condition, previously labeled oculoleptomeningeal amyloidosis, is linked to a mutation at codon 30 of TTR gene, resulting in the substitution of valine with glycine in this family, TTR amyloid deposits were present in the leptomeninges, especially the leptomeningeal vessels, and in the subependymal regions of the ventricular system where they disrupted the ependymal lining and resulted in amyloid-glial formations protruding into and narrowing the ventricular system. Hydrocephalus and atrophy and infarction of cerebral and cerebellar cortexes were also present. Review of the literature shows that amyloid deposition in the leptomeninges is not uncommon in TTR amyloidoses clinically characterized by peripheral neuropathy and lack of CNS signs. The present kindred, which presented exclusively with signs of CNS involvement, expands the phenotype of TTR amyloidosis and raises questions concerning the mechanisms determining phenotypic expression in TTR familial amyloidosis.

Cloning of the cDNA for a human homologue of the Drosophila white gene and mapping to chromosome 21q22.3

In an effort to contribute to the transcript map of human chromosome 21 and the understanding of the pathophysiology of trisomy 21, we have used exon trapping to identify fragments of chromosome 21 genes. Two trapped exons, from pools of chromosome 21-specific cosmids, showed homology to the Drosophila white (w) gene. We subsequently cloned the corresponding cDNA for a human homologue of the Drosophila w gene (hW) from human retina and fetal brain cDNA libraries. The gene belongs to the ATP-binding cassette transporter gene family and is homologous to Drosophila w (and to w genes from other species) and to a lesser extent to Drosophila brown (bw) and scarlet (st) genes that are all involved in the transport of eye pigment precursor molecules. A DNA polymorphism with 62% heterozygosity due to variation of a poly (T) region in the 3' UTR of the hW has been identified and used for the incorporation of this gene to the genetic map of chromosome 21. The hW is located at 21q22.3 between DNA markers D21S212 and D21S49 in a P1 clone that also contains marker BCEI. The gene is expressed at various levels in many human tissues. The contributions of this gene to the Down syndrome phenotypes, to human eye color, and to the resulting phenotypes of null or missense mutations are presently unknown.

NHS dentistry--the road to a better future

Dentistry in this country is approaching a major cross roads. Although not everyone will take the same route, now is the time to examine the options and identify a way ahead for the majority. This article seeks to examine the history which has led to the numerous changes and pressures evident in dentistry today; it examines the various components and argues that these lead inexorably to certain conclusions.

A new dinucleotide repeat polymorphism at the telomere of chromosome 21q reveals a significant difference between male and female rates of recombination

We have used a half-YAC containing the human chromosome 21 long-arm telomere to clone, map, and characterize a new dinucleotide repeat polymorphism (D21S1575) close to 21qter. This marker is < 120 kb from the telomeric (TTAGGG)n sequences and is the most distal highly polymorphic marker on chromosome 21q. This marker has a heterozygosity of 71% because of a variable (TA)n repeat embedded within a long interspersed element (LINE) element. Genotyping of the CEPH families and linkage analysis provided a more accurate determination of the full length of the chromosome 21 genetic map. A highly significant difference was detected between male and female recombination rates in the telomeric region: in the most telomeric 2.3 Mb of chromosome 21q, recombination was only observed in male meioses.

Nevus of Ota acquisita of late onset

Nevus of Ota is a melanotic pigmentary disorder characterized by its distinctive cutaneous distribution involving skin innervated by the trigeminal nerve. Most cases are clinically manifest at birth or around puberty; however, acquired lesions in adults have been reported. We report a case of nevus of Ota acquisita that occurred in an eighty-one-year-old man.

Effects of mechanical ventilation on cardiopulmonary function in children after open-heart surgery

The reduction in functional residual capacity (FRC) after anesthesia and thoracic surgery may result in atelectasis, hypoxia, and respiratory failure. Mechanical ventilation reverses the FRC reduction but may also decrease cardiac output and increase the pulmonary vascular resistance index (PVRI) in some patients. The cardiopulmonary effects of stopping mechanical ventilation after open-heart surgery were studied in 17 children. FRC, arterial pH, and PaO2 were significantly reduced, while PaCO2, oxygen consumption, and right ventricular stroke work index significantly increased. Mean FRC on spontaneous respiration was below normal despite continuous positive airway pressure. PVRI increased significantly in patients whose FRC fell below 22 ml/kg on spontaneous respiration. The PVRI increase was most marked in patients with pre-existing pulmonary vascular disease. These results confirm the value of appropriate mechanical ventilation in the early postoperative management of children undergoing open-heart surgery, particularly those with pulmonary vascular disease.

Increased intracranial pressure: an indication to decompress a tension pneumomediastinum

A 7-yr-old boy undergoing treatment for respiratory failure after near-drowning developed a pneumomediastinum. Intracranial hypertension refractory to previously successful therapy led to placement of a mediastinal tube, after which intracranial pressure decreased and was easier to control. A pneumomediastinum may cause intracranial hypertension by interfering with venous drainage from the cranium.