Antibody isotypes in sera of equine fetuses aborted due to Leptospira interrogans serovar pomona-type kennewicki infection

Leptospira-specific antibody isotypes in sera of late term equine fetuses aborted due to Leptospira interrogans serovar pomona-type kennewicki infection were characterized and compared with those of their dams. IgM was the dominant Leptospira-Specific isotype in both fetuses and mares. However, IgGa was the isotype in highest concentration in petal sera and strong Leptospira-specific IgGa but no IgGb and little or no IgG(T) were detected. In contrast, although IgGb was quantitatively the dominant isotype in mares serum, Leptospira-specific serum IgG in aborting mares was dominated by IgG(T) but also included large amounts of IgGa and IgGb. IgGa and IgGb were quantitatively the dominant isotypes in sera of fetuses and mares, respectively. Affinity purified IgGa from fetuses did not agglutinate leptospires but serum devoid of IgGa did, suggesting that IgM is the principal agglutinating antibody. It is concluded that the equine fetus is deficient in IgGb and IgG(T) synthesis.

Nonspecific stimulation of the maternal immune system. I. Effects On teratogen-induced fetal malformations

BACKGROUND

Maternal immune stimulation has reported, but unconfirmed, efficacy for reducing chemical-induced morphologic defects in mice.

METHODS

Teratogenic chemicals (2,3,7, 8-tetrachlorodibenzo-p-dioxin [TCDD], ethyl carbamate [urethane], methylnitrosourea [MNU], or valproic acid [VA]) were given to pregnant mice to induce cleft palate (TCDD, urethane), digital defects (urethane, MNU), or exencephaly (VA). Before teratogen administration, the immune system of female mice was stimulated by intraperitoneal (IP) administration of pyran copolymer or attenuated bacillus Calmette Guérin (BCG), or by footpad injection with Freund's complete adjuvant (FCA).

RESULTS

Fetal defects caused by all four chemicals studied were reduced by maternal immunostimulation, sometimes dramatically. In addition to reducing VA-induced exencephaly, immunostimulation with FCA resulted in fetal mice displaying anury (absence of tails). Activated maternal immune cells could not be detected in fetal circulation using flow cytometry and a fluorescent cell-tracking probe.

CONCLUSIONS

For the chemicals tested, maternal immune stimulation has efficacy in reducing fetal defects. Immune protection against teratogenesis may be an indirect effect of maternal immune cell activation.

Nonspecific stimulation of the maternal immune system. II. Effects on gene expression in the fetus

BACKGROUND

Maternal immune stimulation reduces malformations caused by chemical teratogens. Mechanisms for this effect are not known. Altered expression of regulatory molecules (e.g., transforming growth factor [TGF-beta], tumor necrosis factor-alpha [TNF-alpha]) has been reported in fetuses from immunostimulated mice, which may affect gene expression. Expression of selected genes that function to control proliferation, differentiation, or apoptosis was evaluated in chemical-exposed fetuses, with or without maternal immunostimulation.

METHODS

Ethyl carbamate (urethane) was given to pregnant ICR mice on day 10 of gestation to induce cleft palate. Before teratogen administration, the immune system of the female mice was stimulated by footpad injection with Freund's complete adjuvant (FCA) or by intraperitoneal injection with interferon-gamma (IFN-gamma).

RESULTS

Maternal immunostimulation with interferon-gamma (IFN-gamma) decreased severity of the cleft palate lesion caused by urethane, while FCA decreased both incidence and severity of cleft palate. Gestation day 14 fetuses from urethane-exposed mothers displayed decreased expression of cell cycle/apoptotic genes bcl2alpha, bcl2beta, pkCalpha, and p53 in fetal heads. Immune stimulation with IFN-gamma-normalized expression of bcl2alpha, bcl2beta, and pkCalpha to control levels. Urethane also decreased the ratio of expression of bclalpha/p53, bclbeta/p53, and pkCalpha/p53, while maternal injection with IFN-gamma restored these expression ratios to control levels. Maternal immunization with FCA also significantly increased bcl2alpha/p53, bcl2beta/p53, and pkCalpha/p53 gene expression ratios.

CONCLUSIONS

These results suggest that (1) the maternal immune system may possess heretofore unrecognized regulatory activity in fetal development, and (2) protection against urethane-induced cleft palate may be mediated through maternal immune regulation of fetal gene expression.

Health effects of daily indoor nitrogen dioxide exposure in people with asthma

Household gas appliances produce nitrogen dioxide (NO2), which may be associated with an increase in symptoms in asthmatics. The relationship between indoor NO2 exposure, and respiratory symptoms in people with asthma was evaluated. Self-reported asthmatics (n=125) wore lapel badges that measured NO2 daily over 6 weeks at home. Outdoor pollutants, spores and meteorological parameters were measured daily, in addition to smoking status and demographic factors. Seven asthma symptoms were recorded in diaries, for analysis by same day and also with 1 day lag exposures, using a generalized estimating equation. Significant interactions were demonstrated between NO2 at age < or =14 yrs, with respect to the symptoms of chest tightness on the same day (odds ratio (OR): 1.29, 95% confidence interval (CI): 1.16-1.43) and with a 1 day lag (OR: 1.29, 95% CI: 1.14-1.46), breathlessness on exertion with a 1 day lag (OR: 1.13, 95% CI: 1.00-1.28), daytime asthma attacks on the same day (OR: 1.13, 95% CI: 1.02-1.26) night asthma attacks on the same day (OR: 1.16, 95% CI:1.03-1.30) and with a 1 day lag (OR: 1.15, 95% CI; 1.03-1.29) after adjustment for potential confounders. A significant interaction between NO2 and age 35-49 yrs was demonstrated for coughs with a 1 day lag (OR: 1.15, 95% CI: 1.01-1.31). Daily personal exposures to NO2 are associated with asthmatic symptoms in children.

In vitro kinetics of coumarin 3,4-epoxidation: application to species differences in toxicity and carcinogenicity

Coumarin, a natural product and fragrance ingredient, is a well recognized rat liver toxicant, and dietary administration at toxic dosages increased the incidence of rat cholangiocarcinomas and parenchymal liver-cell tumors in a chronic bioassay. Hepatotoxicity in rats is site- and species-specific, and is thought to result from the formation of coumarin 3,4-epoxide and its rearrangement product, o-hydroxyphenylacetaldehyde (o-HPA). The goals of the current study were to describe the in vitro kinetics of the metabolic activation of coumarin, and determine whether species differences in susceptibility to liver injury correlate with coumarin bioactivation determined in vitro. Coumarin 3,4-epoxidation was quantified via the formation of o-HPA in pooled hepatic microsomes from female B6C3F1 mice, male F344 rats, and individual humans (n = 12 subjects), and the apparent kinetic constants for o-HPA production were calculated using nonlinear regression and fitting to either a one-enzyme or two-enzyme model. Eadie-Hofstee analyses indicated that o-HPA formation was biphasic in both rat and mouse liver. Although the apparent high affinity K:(m) in rat and mouse liver microsomes was 38.9 and 47.2 microM, respectively, the overall rate of o-HPA formation was far greater in mouse than in rat liver microsomes. Furthermore, the total clearance (CL(int)) of coumarin via o-HPA formation in mouse liver microsomes was 4-fold greater than in rat liver microsomes. Since mice are relatively resistant to hepatotoxicity, the data indicated that rates of o-HPA formation in rat and mouse liver microsomes were not directly predictive of liver toxicity in vivo, and further suggested that o-HPA detoxification played a role in modulating coumarin-mediated toxicity. The current studies also indicated that coumarin 3,4-epoxidation in human hepatic microsomes was minimal. In human liver microsomes (n = 12), the kinetics of o-HPA formation were best described by a single enzyme model, with the K(m) for o-HPA formation ranging from 1320-7420 microM. In the most active human sample, the intrinsic clearance of coumarin via the 3,4-epoxidation pathway was 1/9 and 1/38 that of the rat and mouse, respectively. The in vitro kinetics of o-HPA formation, and in particular, the large quantities of coumarin required for o-HPA production in human liver microsomes, strongly suggest that humans are unlikely to produce toxicologically relevant concentrations of this metabolite following low level coumarin exposures.

High-level periplasmic expression in Escherichia coli using a eukaryotic signal peptide: importance of codon usage at the 5' end of the coding sequence

We investigated the ability of signal peptides of eukaryotic origin (human, mouse, and yeast) to efficiently direct model proteins to the Escherichia coli periplasm. These were compared against a well-characterized prokaryotic signal peptide-OmpA. Surprisingly, eukaryotic signal peptides can work very efficiently in E. coli, but require optimization of codon usage by codon-based mutagenesis of the signal peptide coding region. Analysis of the 5' of periplasmic and cytoplasmic E. coli genes shows some codon usage differences.

Active site modulation in the N-acetylneuraminate lyase sub-family as revealed by the structure of the inhibitor-complexed Haemophilus influenzae enzyme

The N-acetylneuraminate lyase (NAL) sub-family of (beta/alpha)(8) enzymes share a common catalytic step but catalyse reactions in different biological pathways. Known examples include NAL, dihydrodipicolinate synthetase (DHDPS), d-5-keto-4-deoxyglucarate dehydratase, 2-keto-3-deoxygluconate aldolase, trans-o-hydroxybenzylidenepyruvate hydrolase-aldolase and trans-2'-carboxybenzalpyruvate hydratase-aldolase. Little is known about the way in which the three-dimensional structure of the respective active sites are modulated across the sub-family to achieve cognate substrate recognition. We present here the structure of Haemophilus influenzae NAL determined by X-ray crystallography to a maximum resolution of 1.60 A, in native form and in complex with three substrate analogues (sialic acid alditol, 4-deoxy-sialic acid and 4-oxo-sialic acid). These structures reveal for the first time the mode of binding of the complete substrate in the NAL active site. On the basis of the above structures, that of substrate-complexed DHDPS and sequence comparison across the sub-family we are able to propose a unified model for active site modulation. The model is one of economy, allowing wherever appropriate the retention or relocation of residues associated with binding common substrate substituent groups. Our structures also suggest a role for the strictly conserved tyrosine residue found in all active sites of the sub-family, namely that it mediates proton abstraction by the alpha-keto acid carboxylate in a substrate-assisted catalytic reaction pathway.

The intersection of health informatics and evidence-based medicine: computer-based systems to assist clinicians

Evidence-based medicine and health informatics may assist clinicians contend with the current barriers to the integration of evidence-based "best practice" into typical healthcare settings. Computer-based decision support systems can improve the process of care, but whether they improve patient outcomes in a cost-effective manner is uncertain.

Promoting physical activity in general practice: a controlled trial of written advice and information materials

OBJECTIVE

To investigate the impact of a simple written prescription for physical activity given by a general practitioner and the effect of supplementing this with mailed information materials about physical activity.

METHODS

A controlled trial was conducted in 27 general practices in New South Wales, Australia. Subjects were sequential routine care patients between 25 and 65 years old. Controls (n = 386) were recruited first, and intervention subjects two weeks later. Intervention subjects were randomised to receive a prescription only (n = 380) or a prescription plus a mailed booklet (n = 376). Self reported physical activity levels were measured by interview at baseline, 6-10 weeks, and seven to eight months.

RESULTS

By intention to treat, the average changes in minutes of total physical activity did not differ significantly between the groups. Inactive people in the prescription plus supplementary booklet group were significantly more likely than controls to report an increase in their physical activity by at least 60 min/week after 6-10 weeks (odds ratio 1.58, 95% confidence interval 1.06 to 2.35). No significant short term improvements in self reported activity were shown in the prescription only group. In the supplemented group, the proportion reporting an increase in physical activity to 3,344 kJ/week at 6-10 weeks was not significant, and neither intervention group showed significant increases in any of the outcome measures at seven to eight months by intention to treat. Treatment received analysis showed greater improvements in intervention groups, especially the prescription plus booklet group, in which the odds of inactive people in this group reporting increased activity became significant at seven to eight months.

CONCLUSIONS

A prescription for physical activity from a general practitioner, supplemented by additional written materials, can lead to modest short term improvements in self reported physical activity levels among inactive patients. A prescription alone was found not to be effective.

Gross morphology and topography of the adult intestinal tract of the tilapian fish, Oreochromis niloticus L

The intestinal tract of the Nile tilapia, Oreochromis niloticus L., follows a complex course involving multiple loops and coils arranged in a previously undescribed form. From cranial to caudal, five principal regions were identified and designated as the hepatic loop (HL), proximal major coil (PMC), gastric loop (GL), distal major coil (DMC), and terminal segment (TS). The first four of these regions each possessed a reversal flexure and thus could be divided into proximal and distal limbs. Only the terminal segment was straight and undivided. The PMC and DMC were disposed in a spiral, cone-shaped mass (spiral intestine) - their proximal and distal limbs are thus designated as centripetal and centrifugal limbs. These spiral limbs were arranged with each successive limb nested internal to the previous one. Beginning from the stomach, the complete course of the gut including designations of the subdivisions of the major regions was as follows: proximal limb of the HL, distal limb of the HL, centripetal limb of the PMC, centrifugal limb of the PMC, proximal limb of the GL, distal limb of the GL, centripetal limb of the DMC, centrifugal limb of the DMC, and the TS. Though the topographical relations of the various gut loops permitted ready identification of each, external surface features were so similar among the segments that extirpated segments of gut could not be identified as to region of origin. The nesting of successive intestinal loops of the spiral intestine in this fish is novel among patterns previously described, and also among the more intricate of those that have been described.

Factors associated with hospital admissions and repeat emergency department visits for adults with asthma

BACKGROUND

A small proportion of patients with asthma account for a disproportionate number of acute health service events. To identify whether factors other than severity and low socioeconomic status were associated with this disproportionate use, a prospective study was undertaken to examine management and psychosocial factors associated with increased risk for admission to hospital with asthma and repeat visits to the emergency department over a 12 month period.

METHODS

A total of 293 patients with moderate or severe asthma managed at least in part at two teaching hospitals completed surveys of clinical status, acute events, sociodemographic, and psychological variables.

RESULTS

Twenty three percent had a single admission to hospital and 16% had two or more hospital admissions. Twenty six percent had one emergency department visit and 32% had two or more visits to the emergency department. In a multiple logistic regression model, adjusted for age, sex, education and income, odds ratios (95% CI) for baseline factors associated with hospital admissions over the next 12 months were: moderate severity compared with severe asthma 0.6 (0.2 to 0.9); no hospital admissions in the past 12 months 0.1 (0.01 to 0.2); not possessing a written asthma action plan 4.0 (1.5 to 10.7); less use of an avoidance coping style 0.4 (0.3 to 0.7); lower preferences for autonomy in asthma management decisions 1.4 (0.96 to 2.0). Adjusted odds ratios (95% CI) for repeat emergency department visits were: moderate asthma severity 0.3 (0.1 to 0.8); current regular use of oral corticosteroids 10.0 (3.1 to 32.4); a hospital admission in the past 12 months 2.9 (1.8 to 4.8); not possessing a written asthma action plan 2.2 (1.1 to 5.6); less dislike of asthma medications 0.7 (0.5 to 0.9).

CONCLUSIONS

In addition to factors relating to severity, not possessing a written asthma action plan, avoidance coping, and attitudes to self-management were related to acute use of health services in this at risk group. Interventions need to address or take these factors into account to reduce asthma morbidity.

Heavy metal concentrations in surface sediments in a nearshore environment, Jurujuba Sound, Southeast Brazil

Sixty-four surface sediment samples and seven cored samples were collected from the partially closed bay of Jurujuba Sound, an inlet of Guanabara Bay in Southeast Brazil. Analysis of metals, including Pb, Zn, Ni, Cu and Cr, shows levels consistent with those typically found in urbanised and industrialised estuarine environments. Metal enrichment is concentrated around the inshore margin of the Sound and is significantly in excess of background, geological concentrations observed in basal muds from the seven cores. In the absence of industrialisation within the steep, but limited catchment that feeds into the Sound, the metal enrichment, particularly of Pb, Zn and Cu, is ascribed to the uncontrolled discharge of untreated sewage waste and urban surface runoff. This has increased markedly since the beginning of rapid urbanisation following the linking of the area by bridge to Rio de Janeiro in 1974.

The APS adapter protein couples the insulin receptor to the phosphorylation of c-Cbl and facilitates ligand-stimulated ubiquitination of the insulin receptor

The APS adapter protein is rapidly tyrosine-phosphorylated following insulin stimulation. In insulin-stimulated 3T3-L1 adipocytes, APS co-precipitated with phosphorylated c-Cbl. In CHO.T-APS cells overexpressing the insulin receptor and APS, APS co-precipitated with c-Cbl but not in CHO.T cells which do not express APS. APS-mediated recruitment of c-Cbl to the insulin receptor led to rapid ubiquitination of the insulin receptor beta-subunit in CHO. T-APS but not in parental CHO.T cells. These results suggest that the function of APS is to facilitate coupling of the insulin receptor to c-Cbl in order to catalyse the ubiquitination of the receptor and initiation of internalisation or degradation.

Residential radon gas exposure and lung cancer: the Iowa Radon Lung Cancer Study

Exposure to high concentrations of radon progeny (radon) produces lung cancer in both underground miners and experimentally exposed laboratory animals. To determine the risk posed by residential radon exposure, the authors performed a population-based, case-control epidemiologic study in Iowa from 1993 to 1997. Subjects were female Iowa residents who had occupied their current home for at least 20 years. A total of 413 lung cancer cases and 614 age-frequency-matched controls were included in the final analysis. Excess odds were calculated per 11 working-level months for exposures that occurred 5-19 years (WLM(5-19)) prior to diagnosis for cases or prior to time of interview for controls. Eleven WLM(5-19) is approximately equal to an average residential radon exposure of 4 pCl/liter (148 Bq/m3) during this period. After adjustment for age, smoking, and education, the authors found excess odds of 0.50 (95% confidence interval: 0.004, 1.81) and 0.83 (95% percent confidence interval: 0.11, 3.34) using categorical radon exposure estimates for all cases and for live cases, respectively. Slightly lower excess odds of 0.24 (95 percent confidence interval: -0.05, 0.92) and 0.49 (95 percent confidence interval: 0.03, 1.84) per 11 WLM(5-19) were noted for continuous radon exposure estimates for all subjects and live subjects only. The observed risk estimates suggest that cumulative ambient radon exposure presents an important environmental health hazard.

A direct brain interface based on event-related potentials

Cross-correlation between a trigger-averaged event-related potential (ERP) template and continuous electrocorticogram was used to detect movement-related ERP's. The accuracy of ERP detection for the five best subjects (of 17 studied), had hit percentages >90% and false positive percentages <10%. These cases were considered appropriate for operation of a direct brain interface.

Analysis of apoptosis of lymphoid cells in fish exposed to immunotoxic compounds

BACKGROUND

Chemical induction of apoptosis in cells is believed to contribute to toxicity. Techniques for measuring apoptosis have increased in both sensitivity and number and in many cases can be readily extended to nontraditional research species. A comparison of established assays for measuring apoptosis of lymphoid cells has thus far not been performed in the fish and thus would be efficacious in assessing immunotoxicity.

METHODS

The present study evaluated chemical-induced immune cell apoptosis in fish (tilapia, Oreochromis niloticus) exposed to two known immunotoxic chemicals, azathioprine and T-2 toxin. Cytocentrifugation and light microscopy of leukocyte-enriched cell samples from the pronephros (i.e., the fish primary hematopoietic compartment) demonstrated chemical-related increases in apoptotic bodies. This observation was examined further with the ApoAlert Annexin V Apoptosis kit and two DNA-binding dyes employed for detecting apoptosis, 7-aminoactinomycin D (7-AAD) and propidium iodide (PI).

RESULTS

The apoptotic probes confirmed the microscopic observations of increased apoptosis in the chemical-exposed fish. The ApoAlerttrade mark annexin V and 7-AAD assays, which discriminate early and late apoptosis/necrosis, compared well in identifying apoptotic populations. PI staining in Vindelov's solution was unable to detect early apoptosis.

CONCLUSIONS

The present data suggest that apoptotic immune cells may be a useful marker for certain immunotoxicant exposures in fish. These findings agree with those of previous reports that fish may respond immunologically in a manner similar to mammals after immunotoxicant challenge.

Validity of a modified version of the Marks Asthma Quality of Life Questionnaire

To produce a scale useful for individual clinical decision making, the Marks Asthma Quality of Life Questionnaire (AQLQ-M) was modified to a 22-item scale using a 7-point Likert response scale, and the validity of the new instrument was assessed. Adult asthma subjects with moderate to severe disease, recruited from two hospitals in Adelaide, Australia, were surveyed at baseline (n = 293), and at 3-month follow-up (n = 234). Cronbach's alpha for the Total scale of the modified AQLQ-M (MAQLQ-M) was 0.97 and all subscale values exceeded 0.90. Test-retest reliability values for all scales were between 0.88 and 0.93. All correlations between disease reference measures were statistically significant to at least the p < 0.01 level. Stronger associations were seen with symptom and self-rating scales than for lung function, medication usage, and health service utilization measures of outcome. The MAQLQ-M showed good discriminative ability for all asthma symptom categories and for different FEV1 values. Moderate, statistically significant associations were seen between changes in MAQLQ-M scores and clinical measures. Higher baseline MAQLQ-M scores were associated with lower risks over 12 months for hospital admissions (odds ratio, OR = 0.58) and repeated emergency department visits (OR = 0.47). The MAQLQ-M is a highly valid measure of asthma-related quality of life.

A 5-year prospective study of Astra single tooth implants

AIM

To evaluate the AstraTech Implant ST (Molndal, Sweden) for single tooth replacement clinically and radiographically after 5 years in function.

SUBJECTS AND METHOD

Fifteen patients (age range 16 to 48) with missing maxillary anterior teeth (6 central incisors, 8 laterals, 1 bicuspid) had four 13 mm and eleven 15 mm single tooth implants provided. All patients were seen at 4- to 6-monthly intervals for oral hygiene maintenance. Periapical radiographs using Rinn holders and a long cone technique were taken at the crown insertion and after 1 year, 3 and 5 years.

RESULTS

No implant losses were observed in 14 of the 15 patients available for evaluation. No abutment screw loosening or soft tissue problems were observed. At crown insertion the mean bone level was 0.46 +/- 0.55 to 0.48 +/- 0.56 mm apical to the top of the implant neck and there were no statistically significant changes in the radiographic bone level over the 5 years of the study (0.36 +/- 0.37 to 0.43 +/- 0.46 mm at year 5). One crown was recemented after 18 months in function and 1 crown was replaced because of a fracture to the porcelain incisal edge.

CONCLUSION

The Astra Tech Implants ST were highly successful in single tooth replacement and bone levels during 5 years of function were stable.

Ictal spiking patterns recorded from temporal depth electrodes predict good outcome after anterior temporal lobectomy

PURPOSE

Investigators have shown that the presence of ictal spiking (IS) recorded from temporal depth electrodes is associated with mesial temporal sclerosis (MTS). We investigated the relation of IS to seizure control and pathology after anterior temporal lobectomy (ATL).

METHODS

All patients undergoing intracranial ictal monitoring from a single institution since 1989 were identified. Those who did not undergo ATL or had postoperative follow-up of <1 year were excluded. All received at a minimum bilateral temporal depth electrodes. Ictal recordings were reviewed for the presence of IS, and the proportion of seizures with IS was determined for each patient. Outcome was determined by using Engel's classification. Surgical specimens were reviewed for pathology. Statistics used were chi2, Fisher exact test, and Wilcoxon rank sum.

RESULTS

Forty patients with 571 seizures were reviewed. In 292 seizures from 32 patients, IS was seen. Outcomes were 24 class I (22 with IS), five class II (four with IS), three class III (one with IS), seven class IV (four with IS), and one lost to follow-up (with IS). Pathologic review revealed 25 with MTS, 22 of whom had IS. The presence of IS was associated with class I outcomes (p = 0.04), but not MTS (p = 0.06). Patients with class I outcomes had a significantly greater proportion of seizures with IS (mean, 0.58 +/- 0.3) compared with other outcomes (mean, 0.30 +/- 0.3, p = 0.02).

CONCLUSIONS

The presence of IS and higher proportion of seizures with IS correlated with good seizure outcome after ATL. This information may be used in preoperative counseling.

Improved efficiency of site-specific copper(II) ion-catalysed protein cleavage effected by mutagenesis of cleavage site

The peptide sequence (N)DKTH(C) was previously investigated as a site for efficient, specific cleavage of a fusion protein by cupric ions using a humanized gamma1 Fab' as a model protein. Here we show that conservative mutations to three of the residues in the introduced cleavage site resulted in cleavage sites that were significantly improved. They were cleaved more efficiently by Cu(2+), such that cleavage reactions could be shorter, of lower pH or at a lower temperature. Some were even found to be measurably cleaved by Ni(2+). Use of these new cleavage sequences along with cupric ions may provide a more rapid and less harsh method for cost-effective, large-scale proteolytic cleavage of fusion proteins and peptides.

Pulmonary alveolar proteinosis: two contrasting cases

Pulmonary alveolar proteinosis is a rare condition characterized by the abnormal accumulation of surfactant-like material within the alveolar spaces and distal bronchioles. Two cases with contrasting modes of presentation, course, and response to therapeutic whole lung lavage are described. Both cases were in hypoxaemic respiratory failure at the time the definitive diagnosis was made, and in both cases the diagnosis was made by segmental bronchoalveolar lavage following negative open lung biopsy. In neither was an underlying causative organism or agent identified. In one case the alveolar proteinosis developed in late pregnancy, a presentation that is previously unreported. Clinical improvement in this case required repeated whole lung lavages and was accompanied by a trend towards normalization of the ratios of surfactant protein-A and surfactant protein-B to disaturated phospholipid, ratios which may be useful as prognostic indicators. The response to therapeutic lavage was markedly different in the two cases, and it is postulated that this may relate to the fact that alveolar proteinosis is a heterogeneous disease and that the course and response to treatment may relate in part to the specific composition of the abnormal proteinaceous fluid.

Use of 16S rDNA sequences as signature characters to identify Xylella fastidiosa

The nucleotide sequences of 16S rDNAs (coding for the small subunit ribosomal RNAs) were used to identify Xylella fastidiosa, a nutritionally fastidious plant pathogenic bacterium. The near-complete 16S rDNAs from nine strains of Xyl. fastidiosa, including seven pathotypes and one strain of Xanthomonas campestris pv. campestris, were amplified through PCR with two conserved primers (forward primer 5'-AGA GTT TGA TCC TGG CTC AG-3' and reverse primer 5'-AAG GAG GTG ATC CAG CC-3') and sequenced. The 16S sequences were compared with all eukaryote and prokaryote DNA entries in GenBank database. A Xyl. fastidiosa 16S rDNA sequence, M26601, was determined to be the most similar to all the near-complete (1537 bp) and partial 5' end sequences from Xyl. fastidiosa, but not those from the Xanthomonas strain. A 20-bp oligonucleotide (5'-TTG GTA GTA ATA CCA TGG GT-3') was found to be highly characteristic of Xyl. fastidiosa. Since the 16S rDNA of Xyl. fastidiosa strains are highly homologous and characteristically different from other bacteria, including the most closely related Xanthomonas, 16S rDNA sequences can be used as signature characters to identify this bacterium.

Flumazenil discrimination by humans under a two-response and a novel-response procedure

In this study we assessed the discriminative stimulus, self-reported, and performance effects of flumazenil in humans. The first group (n = 6) was trained to discriminate flumazenil (0.56 mg/70 kg i.v.) from saline and tested with flumazenil (0.10, 0.32, 0.56, and 1.0 mg/70 kg) under a two-response drug discrimination procedure. The second group (n = 8) was trained to discriminate flumazenil (0.56 mg/70 kg i.v.) from saline and tested with flumazenil (0.32, 0.56, and 1.0 mg/70 kg), midazolam (0.10, 0.56, and 1.0 mg/70 kg), and caffeine (75 mg/70 kg) under a novel-response drug discrimination procedure. In both groups, flumazenil was acquired and maintained as a discriminative stimulus. Flumazenil dose-dependently increased flumazenil-appropriate responding and ratings of strength of drug effect and sedation, and decreased ratings of stimulant effects and psychomotor performance. Under the novel-response procedure, midazolam produced dose-dependent increases in flumazenil-appropriate responding. However, midazolam produced 43 and 25% novel responding at the intermediate and highest test doses, respectively. Midazolam dose-dependently increased ratings of strength of drug effect and sedation, and decreased ratings of stimulant effects and psychomotor performance. The magnitude of effects on ratings of strength of drug effect and sedation were comparable after flumazenil and midazolam, but psychomotor performance effects were greater after midazolam than after flumazenil. Caffeine produced mostly saline-appropriate responding. The results indicate that flumazenil has agonist effects similar to those of midazolam; however, novel responding after midazolam, and the greater performance decrement after midazolam, suggest that flumazenil does not act as a traditional benzodiazepine agonist.

Ultrastructural morphology of the gill of the hybrid striped bass (Morone saxatilis x M. chrysops)

The fine structure of the principal cell types found in the gill filaments and secondary, respiratory lamellae of the hybrid striped bass (Morone saxatilis x M. chrysops) was studied by transmission electron microscopy. Most of the cell types generally resembled those observed at this level of resolution in other euryhyaline, teleostean species, and the mucus cells, epithelial cells, and cartilage cells were non-distinctive. Pillar cells were atypically flattened within the lamellae. The extensive cytoplasmic tubular system of the chloride cells was more densely distributed and was less branched than reported for many other teleosts. The vascular endothelial cells of the marginal, lamellar blood vessels were particularly striking because of their prominent, electron-dense cytoplasmic granules. Although the physiological function and chemical composition of these granules remain obscure, their presence suggests an important role of secretion into the vascular lumen. These gill data from normal specimens of this sport and commercial, hybrid species constitute a useful basis for interpreting gill changes in diseased striped bass.

Industry, air quality, cigarette smoke and rates of respiratory illness in Port Adelaide

OBJECTIVES

To examine the prevalence of self-reported asthma, bronchitis/emphysema, wheezing, night cough and smoking in Port Adelaide; to explore the relationship of the disorders to the presence of industry, tobacco smoke, indoor appliances and air quality.

METHODS

Prevalence data from a 1995 survey of Port Adelaide residents were compared with data from the 1995 National Health Survey and the 1995 South Australian Health Omnibus Survey. These data were then compared across three geographic areas in Port Adelaide, one being highly industrialised. Their relation to tobacco smoke and the presence of unflued gas appliances were examined. Finally, outdoor gaseous air pollutants were examined across the three areas.

RESULTS

Males in Port Adelaide had higher rates of asthma and bronchitis/emphysema than nationally. Asthma was significantly higher for children aged 5-14 years and for adults aged 25-44 years. Bronchitis/emphysema was significantly higher for males aged 25-64. The highly industrial area had a higher rate of asthma (OR 1.85, 95% CI 1.07-3.22) in males that appeared unrelated to smoking or ambient gaseous pollutants. Smoking in Port Adelaide was significantly higher than in the general population, and was significantly associated with wheeze, night cough and bronchitis/emphysema. The presence of unflued gas heaters at home was significantly associated with asthma prevalence in males (OR 3.27, 95% CI 1.40-7.64).

CONCLUSIONS

Respiratory disease appeared to be independently related to an area of high industry, smoking and presence of unflued gas appliances in Port Adelaide.

Thrombolysis in acute myocardial infarction: analysis of studies comparing accelerated t-PA and streptokinase

OBJECTIVES

To compare outcomes from accelerated alteplase (recombinant tissue plasminogen activator, t-PA) and streptokinase use in acute myocardial infarction.

METHODS

Review of available studies identified by Medline and other literature searches that met the criteria of being a prospective, randomised clinical trial enrolling over 1000 patients with acute myocardial infarction. The studies had to contain an intervention arm comprising accelerated infusion t-PA, or an intervention arm comprising streptokinase provided accelerated t-PA that was compared in the same trial. Interventions compared were streptokinase 1.5 million units given over one hour compared with accelerated t-PA infusion, with concomitant use of aspirin and heparin, and main outcome measure of 30 day mortality.

RESULTS

Four studies met prespecified criteria, these being the GUSTO I, GUSTO IIb Angioplasty Substudy, GUSTO III, and COBALT trials. There was a total study population of 64,387 patients of whom 20,251 received streptokinase, 19,474 received t-PA, with others receiving different treatment. Pooled data show that accelerated t-PA produces a marginal 30 day mortality advantage compared with streptokinase (6.6% v 7.3%, p = 0.02, Bonferroni adjusted p = 0.12, that is borderline significance, relative risk 0.918, 95% confidence interval 0.854 to 0.986). Any benefit is attributable entirely to patients recruited in the United States in the GUSTO I study. There is an increased incidence of stroke with t-PA.

CONCLUSIONS

The data do not consistently show a 30 day mortality benefit from using t-PA compared with streptokinase in acute myocardial infarction, but do show increased risk of stroke. Streptokinase can be considered the thrombolytic agent of choice.

The effect of a respiratory home nurse intervention in patients with chronic obstructive pulmonary disease (COPD)

BACKGROUND

Chronic obstructive pulmomary disease (COPD) is associated with substantial mortality, morbidity, and costs to the health care system. With the increasing interest in outreach care programmes it is important to evaluate their impact upon patients and health services, for conditions such as COPD.

AIM

To determine the effectiveness of an outreach respiratory nurse in a shared care approach, with collaboration between general practitioners and hospital services, in the management of patients with severe COPD.

METHODS

Patients with severe COPD attending The Queen Elizabeth Hospital, Adelaide participated in a randomised controlled trial of a home based nursing intervention (HBNI) over 12 months with outcome measures including mortality rate, hospital service utilisation, FEV1 and health related quality of life (HRQL) using a modified Dartmouth Primary Care Co-operative Quality of Life questionnaire.

RESULTS

There were 48 subjects in each study arm, with no differences in mortality rate (eight deaths in the HBNI group and seven in the control group), hospital admissions, length of stay, number of outpatient and Emergency Service visits. The study had inadequate follow-up of FEV1 and HRQL within the control group. Within the HBNI group, a small improvement in HRQL (in three of ten indices measured) was demonstrated, despite a deterioration in FEV1 (11% reduction, p=0.04) compared to baseline. Quality of life of HBNI subjects' carers did not change.

CONCLUSION

An increased level of care given by an outreach respiratory nurse in a shared care approach for patients with severe COPD produced small improvements in HRQL but did not result in the prevention of deaths or reduced health care utilisation.

The novel-response procedure in humans

The novel-response drug discrimination procedure is one of several three-choice procedures developed to address interpretational difficulties that can occur under standard two-response procedures. The novel-response procedure is unique among three-choice discrimination procedures by using instructions, rather than explicit training procedures. With the novel-response procedure, participants are trained under a standard two-response (drug vs. placebo) discrimination, and then instructed that in the presence of a drug stimulus unlike either of the training drugs, responses should be made on the novel-response alternative. Several studies have assessed the utility of the novel-response procedure by comparing effects under a standard two-response and the novel-response procedure in participants trained to discriminate triazolam from placebo. Results indicate that the novel-response procedure can increase the selectivity of both placebo- and drug-appropriate responding, and in this way, allows for finer distinctions to be made among sedatives than a standard two-response procedure.

Morbidity and infection in combined subdural grid and strip electrode investigation for intractable epilepsy

The coverage of large surface areas of the brain for electrographic monitoring purposes necessitates a craniotomy to achieve comprehensive sampling. We undertook a review and prospective analysis over 3 years of 38 patients undergoing craniotomy for electrode implantation. The indication for invasive monitoring was to determine candidacy for resective surgery in patients whose seizure focus was not well localized by scalp electroencephalography and other noninvasive testing. Prophylactic cultures from the epidural space were obtained at electrode removal. There were five positive epidural cultures. All five patients went on to seizure-free status. Two positive cultures occurred in patients without obvious infection and who were not treated with antibiotics. Other complications included individual cases of atrial fibrillation, pulmonary edema, postoperative fever, and epidural hematoma. There was no mortality or permanent neurologic morbidity related to craniotomy for electrode placement. There was a 7.9% rate of clinical infection per patient and a 5.7% rate per craniotomy side. This study has identified several factors that significantly correlate with positive epidural culture results: > 100 electrodes, more than ten cables, more than 14 days of implantation, and more than one cable exit site.

Detection of event-related potentials for development of a direct brain interface

The study presented here is part of an ongoing effort to develop a direct brain interface based on detection of event-related potentials (ERPs). In a study presented in a companion article, averaged ERP templates were identified from electrocorticograms recorded during repetition of voluntary motor actions. Here the authors report on the detection of individual motor ERPs within the electrocorticogram using cross-correlation. An averaged ERP template was created from the first half of each electrocorticogram and then cross-correlated with the continuous electrocorticogram from the second half. Points where the cross-correlation value exceeded an experimentally determined detection threshold were considered to be detection points. A detection point was considered to be a valid "hit" if it occurred between 1 second before and 0.25 second after the recorded time of a voluntary action. The difference between the hit and false-positive percentages (HF-difference) was used as a metric of detection accuracy. HF-differences greater than 90 were found for 5 of 15 subjects, HF-differences greater than 75 were found for 8 of 15 subjects, and HF-differences greater than 50 were found for 12 of 15 subjects. The three other subjects with HF-differences less than 50 had electrode locations not well suited for recording movement-related ERPs. Recordings from sensorimotor and supplementary motor areas produced the highest yield of channels with HF-difference greater than 50; however, a number of channels with good performance were found in other areas as well. The results demonstrate the likely prospect of using ERP detection as the basis of a single-switch direct brain interface and that furthermore, there is a good possibility of obtaining multiple control channels using this approach.

Skin care management practices for premature infants

OBJECTIVE

To describe current skin care practices for preterm infants in neonatal intensive care units in the United States. We hypothesized that there would be little consensus among facilities.

STUDY DESIGN

Neonatal intensive care units (n = 823) listed in the 1996 United States Neonatologists Directory (American Academy of Pediatrics, Section on Perinatal Pediatrics) were sent a 28-question survey dealing with many aspects of neonatal skin care along with descriptive data about their neonatal intensive care unit. Descriptive data analysis was performed.

RESULTS

A total of 305 surveys were returned (37% return rate); of these, 241 of the respondents reported admitting infants weighing < or = 1000 gm. Some neonatal skin care practices showed wide consensus (> 70%) (e.g., scrub procedure for staff; use of a skin barrier under tapes/adhesives), whereas other practices showed little consensus (< 30%) (e.g., routine surveillance cultures; use of Aquaphor).

CONCLUSION

Consensus on skin care practices was not found among neonatal intensive care units. Data from this survey can be used to develop studies to examine whether certain skin care management practices can improve neonatal outcomes.

APS, an adapter protein with a PH and SH2 domain, is a substrate for the insulin receptor kinase

APS (adapter protein with a PH and SH2 domain) is the newest member of a family of tyrosine kinase adapter proteins including SH2-B and Lnk. We previously identified SH2-B as an insulin-receptor-binding protein and substrate [Kotani, Wilden and Pillay (1998) Biochem J. 335, 103-109]. Here we show that APS interacts with the insulin receptor kinase activation loop through its SH2 domain and insulin stimulates the tyrosine-phosphorylation of APS. Furthermore, the phosphorylation of activation-loop tyrosine residues 1158 and 1162 are required for this interaction.

Specific detection of Xylella fastidiosa Pierce's disease strains

Pierce's disease (PD, Xylella fastidiosa) of grapevine is the primary pathogen limiting vinifera grape production in Florida and other regions of the southeastern United States. Quick and accurate detection of PD strains is essential for PD studies and control. A unique random amplified polymorphic DNA (PD1-1-2) was isolated from a PD strain from Florida. Fragment PD1-1-2 was cloned, sequenced, and found to be 1005 bp in length. PCR primers were designed to utilize these sequence data for PD strain detection. One primer set (XF176f-XF954r) amplified a 779-bp DNA fragment from 34 PD strains including seven pathotypes of X. fastidiosa, but not from strains of Xanthomonas campestris pv. campestris, Xan. vesicatoria or Escherichia coli. A second primer set (XF176f and XF686r) amplified a 511-bp fragment specific to 98 PD strains, but not from strains of citrus variegated chlorosis, mulberry leaf scorch, oak leaf scorch, periwinkle wilt, phony peach, or plum leaf scald. Sequence analysis indicated that RAPD fragment PD1-1-2 contains a Ser-tRNA gene. The PD-specific region includes a TaqI restriction site (TCGA) and is 150 bp downstream of the Ser-tRNA gene.

The influence of an expert system for test ordering and interpretation on laboratory investigations

BACKGROUND

The Laboratory Advisory System (LAS) is an expert system interface that works interactively with clinicians to assist them with test selection and result interpretation throughout the laboratory investigation of a patient.

METHODS

To study the influence of the LAS on laboratory investigations, a repeated-measures experiment using clinical vignettes was conducted. To collect baseline data on how laboratory investigations are currently conducted, clinicians investigated one-half of the vignettes using a conventional (noncomputer) approach. To determine the influence of the LAS on clinicians' behavior, the other half of the vignettes were investigated using the LAS.

RESULTS

Clinicians using the LAS (compared with conventional practice) ordered fewer laboratory tests during the diagnostic process (mean, 17.8 vs 32.7), completed the diagnostic workup with fewer sample collections (mean, 5.8 vs 7.5), generated lower laboratory costs (mean, $194 vs $232), shortened the time required to reach a diagnosis (mean, 1 day vs 3.2 days), showed closer adherence to established clinical practice guidelines, and exhibited a more uniform and diagnostically successful investigation.

CONCLUSION

The LAS enhances the outcome of the investigation and improves laboratory utilization.

Randomised controlled trial of general practice based asthma clinics

OBJECTIVE

To compare the effects on asthma morbidity of asthma clinics based in general practice with standard general practice care.

DESIGN AND SETTING

A randomised controlled trial in eight general practices. Patients, general practitioners and outcomes assessors were not blinded to treatment allocation.

PARTICIPANTS

195 patients with asthma aged 5-64 years; 191 completed the trial.

INTERVENTION

Three asthma clinic sessions over six months involving nurse counselling, education about asthma management, spirometry and consultation with the general practitioner.

MAIN OUTCOME MEASURES

Patients reporting days lost from work or school, number of days lost, the presence of morning or nocturnal asthma symptoms, use of an action plan, medication use, current smoking, hospitalisation, and emergency visits.

RESULTS

Asthma clinics were associated with a greater reduction in nocturnal symptoms, an increase in the ownership of peak flow meters and an increase in the number of patients commencing or resuming smoking. Both control and intervention groups showed similar improvement in days lost from work or school, the presence of symptoms, use of an action plan and taking reliever medication.

CONCLUSION

Our study does not show that asthma clinics are more effective than standard general practice care in reducing asthma morbidity. It is uncertain how much of the improvement in outcomes was due to the asthma clinic, the influence of the study itself upon patients and practitioners, or other factors, such as the tendency for a patient's asthma management to improve over time.

Talin contains three similar vinculin-binding sites predicted to form an amphipathic helix

Using recombinant talin polypeptides and an SDS/PAGE-blot overlay assay, we have previously identified three regions of talin that are involved in binding to vinculin [Gilmore, Wood, Ohanian, Jackson, Patel, Rees, Hynes and Critchley (1993) J. Cell Biol. 122, 337-347]. We have confirmed these observations by using a yeast two-hybrid assay and shown that talin residues 498-656, 852-950 and 1929-2029 are each capable of binding to vinculin residues 1-258. We have further defined the three vinculin-binding sites in talin to residues 607-636, 852-876 and 1944-1969; alignment of these sequences shows 59% similarity, although there are only two identical residues. Predictions of secondary structure indicate that this vinculin-binding motif forms an amphipathic alpha-helix. The hydrophobic face of helix 607-636 contains three aligned leucines (residues 608, 615 and 622), which show conservative substitutions in the other two sites. To test the possibility that this might constitute a leucine zipper involved in vinculin binding, we mutated each leucine residue to an alanine. The results showed that this leucine repeat is not essential to the interaction between talin and vinculin. We also used the yeast two-hybrid system to define further the talin-binding site within vinculin residues 1-258. C-terminal deletions made in accordance with exon boundaries showed that vinculin residues 1-167 are capable of interacting with each of the three vinculin-binding sites in talin. However, all N-terminal deletions abolished binding. The results suggest that the talin-binding site in vinculin has a relatively complex fold, whereas the vinculin-binding motif in talin is contained within a short linear peptide sequence that is repeated three times in the talin rod domain.

Asthma and chronic obstructive airway diseases are associated with osteoporosis and fractures: a literature review

The objective was to assess the association between asthma and/or chronic obstructive airway diseases (COAD), and osteoporosis, and appraise treatments of osteoporosis in these patients. MEDLINE and Excerpta Medica were searched for original research with control groups which tested the above association. One cohort and nine cross-section studies of bone density in patients with asthma and/or COAD were retrieved. These demonstrated clinically important bone density reductions of up to 29% in subjects, dependent upon daily oral corticosteroids, by a variety of measurement techniques, at various bone sites. Bone density reduction has also been less consistently reported in the absence of oral corticosteroids, suggesting that other factors including high-dose inhaled corticosteroids may have a role. Fracture studies. Three studies in oral corticosteroid-dependent asthmatics demonstrated a vertebral fracture prevalence up to 56%, and annual vertebral fracture incidence of up to 42%. The strength of the available evidence is limited, but suggests that patients with asthma and/or COAD are at increased risk of osteoporosis. The evidence of the association between osteoporosis and inhaled corticosteroids is much more limited than for oral corticosteroids. Bisphosphonates are promising agents to maintain and/or promote bone mass in this patient group.

Comparing single and cumulative dosing procedures in human triazolam discriminators

This study evaluated a cumulative dosing procedure for drug discrimination with human participants. Four participants learned to discriminate triazolam (0.35 mg/70 kg) from placebo. A crossover design was used to compare the results under a single dosing procedure with results obtained under a cumulative dosing procedure. Under the single dosing procedure, a dose of triazolam (0, 0.05, 0.15, or 0.35 mg/70 kg) or secobarbital (0, 25, 75, or 175 mg/70 kg) was administered 45 min before assessment. Determining each dose-effect curve thus required four sessions. Under the cumulative dosing procedure, four doses of triazolam (0, 0.05, 0.10, and 0.20 mg/70 kg) or secobarbital (0, 25, 50, and 100 mg/70 kg) were administered approximately 55 min apart, producing a complete dose-effect curve in one four-trial session. Regardless of procedure, triazolam and secobarbital produced discriminative stimulus and self-reported effects similar to previous single dosing studies in humans. Shifts to the right in cumulative dose-effect curves compared to single dose-effect curves occurred on several self-report measures. When qualitative stimulus functions rather than quantitative functions are of interest, application of cumulative dosing may increase efficiency in human drug discrimination.

Tilapia (Oreochromis niloticus) dosed with azathioprine display immune effects similar to those seen in mammals, including apoptosis

Azathioprine, an anti-neoplastic drug and therapeutic immunosuppressant, was administered intraperitoneally at 10.0 and 50.0 mg/kg to 3-6-month-old tilapia (Oreochromis niloticus). Consistent alterations in immune cellular parameters of the blood, pronephros (hematopoietic kidney) and spleen were observed. Peripheral blood total cellularity decreased as the azathioprine dose increased, to approximately half that of the control. Differential analysis of white blood cells indicated a decline in lymphocyte number, in particular, with increased dosage of azathioprine. Pronephric total cellularity was depressed in fish receiving the 10.0 or 50.0 mg/kg dose. In contrast, both splenic weight and splenic total cellularity increased proportionately with the increase in the drug dosage. Histopathologic examination of the spleens showed normal patterns for both control and 10.0 mg/kg dose groups. At 50.0 mg/kg, spleens were characterized by marked expansion of the white pulp, although lymphocytes were rare. Melanomacrophage centers at the higher dose were also larger and more numerous than in the control group. Evaluation of splenic and pronephric leukocytes with apoptotic markers showed an increase in apoptotic cells in the pronephros with increasing drug dose. These changes in fish are consistent with those seen in humans and laboratory rodents dosed with azathioprine, suggesting that fish may be potentially useful as preliminary models for detecting immunosuppressive compounds.

Gas chromatographic-mass spectrometric analysis of hydroxylamine for monitoring the metabolic hydrolysis of metalloprotease inhibitors in rat and human liver microsomes

A gas chromatographic-mass spectrometric (GC-MS) method was developed for the analysis of hydroxylamine (HA) in supernatants obtained from liver microsomes. HA monitoring was used to determine the metabolic hydrolysis of two hydroxamic acid-based matrix metalloprotease inhibitors in rat and human liver microsomes. The hydrolysis of the hydroxamic acids to their corresponding carboxylic acids releases HA as a common metabolic product. HA was derivatized to acetone oxime by addition of acetone to the liver microsomal supernatant, followed by direct injection of the supernatant into the GC-MS, with detection of the oxime by selected-ion-monitoring. The method is simple, reproducible, and sensitive for the determination of the hydrolysis of hydroxamic acid compounds, where hydrolysis is the major metabolic pathway. The methodology can be used for rank ordering and selecting hydroxamic acid analogs based on their susceptibility to hydrolysis.

Efficient site specific removal of a C-terminal FLAG fusion from a Fab' using copper(II) ion catalysed protein cleavage

The peptide sequence (N)DKTH(C) was investigated as a site for efficient, specific cleavage of a fusion protein by cupric ions using a humanised gamma1 Fab' as a model protein. The native upper hinge (N)DKTH(C) sequence was mutated to create a site resistant to cleavage by cupric ions and a (N)DKTH(C) sequence introduced between the hinge and a C-terminal FLAG peptide. Incubation of Fab' with Cu2+ at 62 degrees C at alkaline pHs resulted in removal of the FLAG peptide with efficiencies of up to 86%. Cleavage conditions did not detrimentally affect the Fab' protein. Use of the (N)DKTH(C) sequence along with cupric ions may provide a cost-effective method for large scale proteolytic cleavage of fusion proteins.

Developing an effective program to complete ictal SPECT in the epilepsy monitoring unit

With the availability of more stable radiopharmaceuticals, the ictal single photon emission computed tomography (SPECT) perfusion study has emerged as a useful noninvasive functional neuroimaging tool in the presurgical evaluation of patients with medically intractable partial epilepsy. The purpose of this study was to determine whether the development of a program using trained electroencephalography (EEG) technologists to perform ictal injections in the epilepsy monitoring unit enabled a more efficient delivery of radiopharmaceuticals and therefore a higher specificity and sensitivity of outcome. All patients admitted to the epilepsy monitoring unit for prolonged video/EEG monitoring as part of the presurgical evaluation were eligible for completion of an ictal SPECT study using a three-way needle-free apparatus. Over a 19-month period, 85 (77%)) of 110 eligible patients were successfully injected during typical partial seizures. Various factors were analyzed including latency of ictal injection (27.3+/-20.8 [S.D.] s), radiopharmaceutical wastage (40% dose utilization), radiation safety parameters (1.6% contamination rate), and preliminary data of localizing value. Our results show that ictal SPECT can be a safe, noninvasive procedure completed on a routine basis in the epilepsy monitoring unit when appropriately trained support staff are utilized as part of a structured multidisciplinary program.

Spatial variation of residential radon concentrations: the Iowa Radon Lung Cancer Study

Homeowners and researchers frequently estimate the radon concentrations in various areas of the home from a single radon measurement often performed in the home's basement. This study describes the spatial variation of radon concentrations both between floors and between rooms on the same floor. The geometric mean basement and first floor radon concentrations for one-story homes were 13.8% and 9.0% higher, respectively, as compared to their counterparts in two-story homes. The median first floor/basement ratio of radon concentrations for one-story homes was 0.60. The median ratios between first floor/basement and second floor/basement for two-story homes were 0.51 and 0.62, respectively. The mean coefficient of variation for detectors placed on the same floor was 9.5%, which was only 2.6% higher than the mean coefficient of variation found for collocated (duplicate) quality control detectors. The wide individual variations noted in radon concentrations serve as a reminder of the importance of performing multiple radon measurements in various parts of the home when estimating home radon concentrations.

Photoreceptor fine structure in Oreochromis niloticus L. (Cichlidae; Teleostei) in light- and dark-adaptation

The structure and arrangement of both light- and dark-adapted retinal photoreceptors of Oreochromis niloticus L. were studied. Eyes of four light-adapted and four dark-adapted O. niloticus were fixed routinely for light and transmission electron microscopy. Rods, single cones, and double (twin) cones were present in a ratio of 30:1:2, respectively. Light-adapted rods were tall, extending into the retinal epithelial layer. Rod inner segments showed a distal ellipsoid of mitochondria that narrowed dramatically in the myoid region. Dark-adapted rod inner segments were much shorter with a thicker myoid region, indicating photomechanical movement. Rod synaptic spherules were small, with both superficial synapses and invaginated sites. Single cones were similar to individual members of a double cone. Cone outer segments consisted of uniform discs with a single incisure. All cones displayed a short, tapering outer segment, a large ellipsoid of mitochondria, and a myoid region rich in organelles. Both members of double cones had extensive subsurface cisternae along their contiguous surfaces. Cone inner segments changed little throughout the circadian cycle, suggesting an absence of significant retinomotor movements. Large, vesicular cone nuclei were located adjacent to or through the external limiting membrane. The cones' synaptic pedicles had larger synapses than rod spherules, with more of both invaginated (ribbon) and conventional (superficial) synaptic sites. Cone photoreceptors were arranged in a repeating square mosaic pattern with a single cone surrounded by four double (twin) cones. The photoreceptors of the Nile tilapia presented basic piscine characteristics, and also some more species-specific features.

Fine structure of the retinal pigment epithelium of Oreochromis niloticus L. (Cichlidae; Teleostei) in light- and-dark adaptation

The fine structure of the retinal pigment epithelium (RPE) of the cichlid Oreochromis niloticus was investigated in both light- and dark-adaptation. The eyes of four light-adapted and from four dark-adapted O. niloticus were fixed routinely for light and transmission electron microscopy. The RPE consisted of a single layer of columnar cells showing minimal basal infolding but plentiful apical processes that in light-adaptation interdigitated with the photoreceptor outer segments. The epithelial cells were joined by a series of basally-located tight junctions. These cells showed a large vesicular nucleus, plentiful smooth endoplasmic reticulum and polysomes, but only small amounts of rough endoplasmic reticulum. Phagosomes, lysosome-like bodies, lipid droplets, and myeloid bodies were observed. The choriocapillaris was a single layer of large-caliber capillaries, and Bruch's membrane (complexus basalis) was a trilaminate structure typical of teleosts. The RPE melanosomes moved basally (sclerally) in dark-adaptation and apically (vitreally) during light-adaptation. Other morphological features which changed at least to some degree during retinomotor responses were: the location of the RPE nucleus; the location and electron density of the mitochondria; and the location, number, and size of the myeloid bodies. A number of unique morphological changes take place within the RPE cells of this species during the circadian cycle in addition to the movement of melanosomes characterized in other vertebrates.