Large exchange-driven intrinsic circular dichroism of a chiral 2D hybrid perovskite

In two-dimensional chiral metal-halide perovskites, chiral organic spacers endow structural and optical chirality to the metal-halide sublattice, enabling exquisite control of light, charge, and electron spin. The chiroptical properties of metal-halide perovskites have been measured by transmissive circular dichroism spectroscopy, which necessitates thin-film samples. Here, by developing a reflection-based approach, we characterize the intrinsic, circular polarization-dependent complex refractive index for a prototypical two-dimensional chiral lead-bromide perovskite and report large circular dichroism for single crystals. Comparison with ab initio theory reveals the large circular dichroism arises from the inorganic sublattice rather than the chiral ligand and is an excitonic phenomenon driven by electron-hole exchange interactions, which breaks the degeneracy of transitions between Rashba-Dresselhaus-split bands, resulting in a Cotton effect. Our study suggests that previous data for spin-coated films largely underestimate the optical chirality and provides quantitative insights into the intrinsic optical properties of chiral perovskites for chiroptical and spintronic applications.

Flattening Grain-Boundary Grooves for Perovskite Solar Cells with High Optomechanical Reliability

Optomechanical reliability has emerged as an important criterion for evaluating the performance and commercialization potential of perovskite solar cells (PSCs) due to the mechanical-property mismatch of metal halide perovskites with other device layer. In this work, grain-boundary grooves, a rarely discussed film microstructural characteristic, are found to impart significant effects on the optomechanical reliability of perovskite-substrate heterointerfaces and thus PSC performance. By pre-burying iso-butylammonium chloride additive in the electron-transport layer (ETL), GB grooves (GBGs) are flattened and an optomechanically reliable perovskite heterointerface that resists photothermal fatigue is created. The improved mechanical integrity of the ETL-perovskite heterointerfaces also benefits the charge transport and chemical stability by facilitating carrier injection and reducing moisture or solvent trapping, respectively. Accordingly, high-performance PSCs which exhibit efficiency retentions of 94.8% under 440 h damp heat test (85% RH and 85 °C), and 93.0% under 2000 h continuous light soaking are achieved.

The complex and often confusing history, histology and histogenesis of mesonephric, STK11 adnexal tumour and mesonephric-like neoplasms of the upper female genital tract (including broad ligament)

Mesonephric lesions in the female genital tract are uncommon, with those arising from the upper tract being much less frequent than those developing in the lower tract (mesonephric hyperplasia and carcinoma). The most common upper tract lesions include rete cyst/cystadenoma and female adnexal tumour of Wolffian origin (FATWO). The integration of morphological, immunohistochemical and molecular studies on FATWOs has enabled recognition of a novel entity, the STK11 adnexal tumour, which is often associated with Peutz-Jeghers syndrome (~50%) and frequently has a salivary gland morphology but an unknown origin. Similarly, 'mesonephric-like' adenocarcinoma, an entity with striking similarities to mesonephric carcinoma but currently favoured to be of Müllerian derivation based on its association with other Müllerian tumours and molecular findings, has also been recently described, and may histologically mimic both FATWOs and STK11 adnexal tumours. In this review, we provide a historical overview of upper female genital tract mesonephric proliferations and discuss mesonephric lesions, STK11 adnexal tumour, mesonephric-like adenocarcinoma, and mimickers, the most common being endometrioid carcinoma.

Callosal disconnection and limb-kinetic apraxia

According to Liepmann, patients with limb-kinetic apraxia (LKA) have a loss of upper limb deftness-dexterity. Prior studies have revealed in right-handed patients that, whereas injury of the left hemisphere induces an ipsilesional LKA, injury to the right hemisphere does not induce an ipsilesional LKA. There are at least two possible means by which the left hemisphere may influence the deftness of the left hand, either by callosal connections or by ipsilesional corticospinal projections. The purpose of this study was to learn whether a patient with a focal lesion of the corpus callosum had a callosal disconnection LKA. This 57-year-old right-handed man had a memory impairment, and upon brain imaging, was found to have a septum pellucidum cyst, which was causing mild ventricular obstruction to the occipital and temporal horns. He underwent an endoscopic-assisted fenestration of the septum pellucidum. Postoperative imaging revealed a lesion of the mesial portion of his corpus callosum and an assessment of praxis revealed that he had both a limb-kinetic and ideomotor apraxia of his left but not his right hand. The observation that this man had a callosal disconnection LKA of his left hand suggests that in some people it is the left hemisphere's premotor or motor cortex that enables the right hemisphere's motor system to program deft movements of the left hand.

Impact + resistance training improves bone health and body composition in prematurely menopausal breast cancer survivors: a randomized controlled trial

Our randomized controlled trial in prematurely menopausal breast cancer survivors showed that impact + resistance training prevented increases in percentage of body fat compared with controls and also improved BMD at the hip and prevented BMD loss at the spine among exercise-trained women who were menopausal for >1 year.

INTRODUCTION

Cancer treatment-related menopause worsens bone health and body composition in breast cancer survivors (BCS). We investigated whether impact + resistance training could improve bone mineral density (BMD), reduce bone turnover, build muscle, and decrease fat mass in BCS with premature menopause.

METHODS

We conducted a randomized controlled trial in 71 BCS (mean age, 46.5 years) within 5 years of treatment-related menopause. Women were randomly assigned to one of two groups: (1) impact + resistance training (prevent osteoporosis with impact + resistance (POWIR)) or (2) exercise placebo (FLEX) 3×/week for 1 year. Outcomes were hip and spine BMD (in grams per square centimeter) and body composition (percent body fat (%BF) and lean and fat mass (in kilograms)) by DXA and bone turnover markers (serum osteocalcin (in nanograms per milliliter) and urinary deoxypryrodinoline (in nanomoles per milliliter).

RESULTS

There were no significant group × time interactions for bone outcomes when using an intent-to-treat approach on the full sample. In analyses restricted to BCS who were menopausal for ≥1 year, POWIR increased BMD at the hip and slowed BMD loss at the spine compared with FLEX (femoral neck-POWIR, 0.004 ± 0.093 g/cm(2) vs. FLEX, -0.010 ± 0.089 g/cm(2); p < 0.01; spine-POWIR, -0.003 ± 0.114 g/cm(2) vs. FLEX, -0.020 ± 0.110 g/cm(2); p = 0.03). POWIR prevented increases in %BF (POWIR, 0.01 % vs. FLEX, 1.3 %; p < 0.04). Women with attendance to POWIR at ≥64 % had better improvements in %BF than women attending less often (p < 0.03).

CONCLUSION

Impact + resistance training may effectively combat bone loss and worsening body composition from premature menopause in BCS.

New insight into transient contrast enhancement on computed tomography after endovascular treatment of stroke

Transient contrast enhancement on computed tomography following endovascular treatment of stroke is a recognized entity that has been previously reported. Technological advances in brain imaging now have the potential to explore and refine its proposed etiology. We describe three patients in whom the location of contrast enhancement correlates with decreased cerebral blood volume on pre-therapeutic CT perfusion studies and with restricted diffusion on MRI. In this regard, contrast enhancement demarcated areas of completed cerebral infarction. The diagnostic and etiological implications are discussed.

Abstract P4-06-24: KLF8 Induction of Mammary Epithelial Stem Cell Formation and Tumorigenesis by Regulating EMT-Associated MicroRNAs

Although it is well established that the epithelial-mesenchymal transition (EMT) generates cells with properties of stem cells, the molecularmechanisms responsible for this change remain largely undefined. We set out to identify the mechanisms by examining the expression of stem cell markers as well as microRNAs in MCF-10A cells during EMT induction. By immunostaining and FACS analysis, we found that during EMT induction by either TGF-β treatment or overexpression of KLF8, both the expression of CD44high/CD24low and the activity of aldehyde dehydrogenase (ALDH) were dramatically increased. Using microRNA PCR array, we identified a microRNA signature associated with the EMT. Using microRNA inhibitor, We further demonstrated that one of the microRNAs, miR-146a, is upregulated and plays an important role in keeping the stem cell percentage during EMT induced by both TGF-β and KLF8, as revealed by manipulation of miR-146a expression, analysis of the stem cell markers and mammosphere growth. Taken together, these results highlight a novel role for miR-146a in regulating the stem-like cell induction from MCF-10A cells by EMT. Experiments are in progress to investigate the contribution of KLF8-regulated expression of miR146a and its targets to the stem cell induction and transformation. Supported by: NIH, ACS, Komen and NYSTEM grants to J.Z.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-06-24.

Endobronchial ultrasound guided transbronchial needle aspiration

Staging for non-small cell lung cancer (NSCLC) requires accurate assessment of the mediastinal lymph nodes which determines treatment and outcome. As radiological staging is limited by its specificity and sensitivity, it is necessary to sample the mediastinal nodes. Traditionally, mediastinoscopy has been used for evaluation of the mediastinum especially when radical treatment is contemplated, although conventional transbronchial needle aspiration (TBNA) has also been used in other situations for staging and diagnostic purposes. Endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) offers a minimally invasive alternative to mediastinoscopy with additional access to the hilar nodes, a better safety profile, and it removes the costs and hazards of theatre time and general anaesthesia with comparable sensitivity, although the negative predictive value of mediastinoscopy (and sample size) is greater. EBUS-TBNA also obtains larger samples than conventional TBNA, has superior performance and theoretically is safer, allowing real-time sampling under direct vision. It can also have predictive value both in sonographic appearance of the nodes and histological characteristics. EBUS-TBNA is therefore indicated for NSCLC staging, diagnosis of lung cancer when there is no endobronchial lesion, and diagnosis of both benign (especially tuberculosis and sarcoidosis) and malignant mediastinal lesions. The procedure is different than for flexible bronchoscopy, takes longer, and requires more training. EBUS-TBNA is more expensive than conventional TBNA but can save costs by reducing the number of more costly mediastinoscopies. Revenue based tariff systems have been slow to reflect the innovation of techniques such as EBUS-TBNA. In the future, endobronchial ultrasound may have applications in airways disease and pulmonary vascular disease.

A prospective study of conventional transbronchial needle aspiration: performance and cost utility

BACKGROUND

Conventional transbronchial needle aspiration (TBNA) is a cheap, minimally invasive tool for lung cancer staging and diagnosis. Endobronchial ultrasound-guided TBNA (EBUS-TBNA) is more sensitive but is more expensive and less widely available. We describe a prospective analysis of TBNA diagnostic, staging and cost utility in a centre in the UK.

OBJECTIVES

To illustrate the potential diagnostic, staging and cost utility of a low cost conventional TBNA service.

METHODS

A prospective analysis of 79 TBNA procedures over a 2-year period was performed looking at performance and cost utility in a 'mixed' cohort with variable pre-test probability of malignancy (year 1) followed by a high probability cohort (year 2).

RESULTS

TBNA avoided mediastinoscopy in 25% of the cases overall (37% in high probability vs. 13% in the 'mixed' cohort, p = 0.03). The overall prevalence of malignancy was 84%, sensitivity 79%, negative predictive value 58% and accuracy 85%. Diagnostic utility varied with pre-test probability and nodal station. TBNA down-staged 8% of lung cancer patients to receive surgery and confirmed the pre-treatment stage (inoperability) in 74%. TBNA led to theoretical cost savings of GBP 560 per patient.

CONCLUSIONS

TBNA can achieve a high diagnostic sensitivity for cancer in high probability patients and stage the majority appropriately, thereby avoiding unnecessary mediastinoscopies and reducing costs. It may also down-stage a minority to have surgery. TBNA is cheap, routinely available and learnable. As EBUS-TBNA will take time to develop due to its costs, all respiratory centres should perform TBNA at flexible bronchoscopy in suspected lung cancer with accessible mediastinal adenopathy.

A local anaesthetic video-assisted thoracoscopy service: prospective performance analysis in a UK tertiary respiratory centre

INTRODUCTION

Local anaesthetic video-assisted thoracoscopy (LAVAT) is a safe, reliable and therapeutic procedure used by respiratory physicians in the management of pleural disease, especially pleural malignancy. We describe a prospective analysis of a UK LAVAT service set up in a tertiary respiratory centre to complement an existing large surgical video-assisted thoracic surgery (VATS) service.

METHODS

A prospective analysis of 125 LAVAT procedures over a 34-month period was performed looking at a variety of quality control endpoints comparing them to national thoracic surgical VATS standards.

RESULTS

Talc pleurodesis was effective in over 86% of cases and this did not significantly lengthen bed stay (median 4.5 days). Bed stay was also unchanged between the ages of 60-89 years. Over 77% of the 48 patients with proven metastatic pleural lung malignancy or mesothelioma received either surgical decortication or oncological treatment (palliative chemotherapy in 57%). In only 6% were biopsies not possible because of technical factors. LAVAT biopsies had a diagnostic accuracy of 97.4%, sensitivity 95.4%, specificity 100%, positive predictive value 100%, and negative predictive value 94.7%. Our complication rate was 4% and mortality rate 0.8%.

DISCUSSION

Our LAVAT service meets surgical VATS standards for diagnosis and safety with a good pleurodesis efficacy rate. It complements our surgical VATS service, offering a pleural diagnostic service for patients with non-complex pleural exudates or too frail for VATS. Our data demonstrate there is a demand and potential for respiratory physicians dealing with pleural malignancy to develop LAVAT and enhance their local lung cancer and pleural diagnostic pathway.

A performance and theoretical cost analysis of endobronchial ultrasound-guided transbronchial needle aspiration in a UK tertiary respiratory centre

BACKGROUND

New innovative techniques can improve patient care but may not be appropriately funded. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS) offers a minimally invasive mediastinal staging and diagnostic method for suspected lung cancer.

AIM

We report the performance and cost analysis of a newly established EBUS service in a prospective real world cohort of patients to assess the impact of Payment by Results (PbR).

DESIGN

Prospective cohort study.

METHODS

Fifty-four patients between June 2008 and April 2009 underwent EBUS for evaluation of unexplained mediastinal lymphadenopathy on CT. Cost analysis was performed from local Trust financial data and 2008-09 tariffs.

RESULTS

EBUS had an 89% sensitivity, 75% negative predictive value and 92% accuracy for malignancy. EBUS coding was inaccurate in 15.6% of cases. The actual cost of an EBUS is 1252-1433 pounds but is coded as a standard bronchoscopy (561 pounds). EBUS reduces health community costs by 107824 pounds/year, as a result of a Primary Care Trust cost saving of 113968 pounds/year and a Trust cost deficit of 6144 pounds/year. Coding inaccuracies further alter the Primary Care Trust costs.

CONCLUSION

Medical innovation is fundamental to improved patient care. EBUS can potentially reduce morbidity for lung cancer patients and save health community costs. However, with PbR the service provider delivers this at a loss as the tariffs do not reflect innovation and because of coding inaccuracies. We suggest tariffs for innovative procedures need to reflect the true cost.

Changes in lung cancer incidence in South Asians in Leicester, 1990-2005

BACKGROUND

A previous study showed that lung cancer incidence in Leicester's South Asian (SA) population had increased between 1990 and 1999. We expanded the original data set to determine if this increase had continued in recent years.

METHODS

All patients diagnosed with lung cancer in Leicester between 1990 and 2005 were identified. Ethnicity was assigned using Nam Pechan software, deprivation by Townsend score. Using Poisson regression, incidence rate ratios (IRRs) were calculated to assess variations in incidence by ethnicity, deprivation and period of diagnosis.

RESULTS

Comparing patients diagnosed in 2000-2005 with those in 1990-1994, the risk of lung cancer increased in the SA men (IRR: 1.67 (95% CI: 0.99, 2.78)) whereas in the non-South Asian (NSA) men, it had fallen (IRR: 0.84 (95% CI: 0.76, 0.94)). Comparing patients diagnosed in 2000-2005 with those in 1995-1999 an increase continued in the SA men (IRR: 1.11 (95% CI: 0.71-1.74)). A significant rise was observed in the NSA women comparing those diagnosed from 2000-2005 to 1995-1999 (IRR: 1.16 (95% CI: 1.01, 1.33)).

CONCLUSION

Lung cancer is an important public health issue amongst SAs in Leicester and has increased significantly since the early 1990s, with rates sustained in the more recent years of 2000-2005. Changes in the rates of lung cancer in SA and NSA populations are likely to be due to changing smoking habits.

Investigating the diet of the omnivorous mirid Dicyphus hesperus using stable isotopes

Omnivory involves numerous feeding relationships and a complex web of interactions. When using omnivores in biocontrol, these interactions need to be understood to maximize feeding on the target species and minimize non-target interactions. Dicyphus hesperus is used along with Encarsia formosa for biocontrol of whiteflies in greenhouse tomato crops. Dicyphus hesperus is a generalist omnivore which feeds on all components of the system. To quantify these interactions, stable isotope analysis was used to identify trophic position with nitrogen isotopes (delta15N) and plant sources with carbon isotopes (delta13C). Feeding trials were used to establish baseline isotopic data for D. hesperus and their diet, including Verbascum thapsus, an alternative plant food. Cage trials were used to monitor population abundances and the isotopic signature of D. hesperus. In feeding trials, D. hesperus were enriched relative to their food, suggesting an elevated trophic position. However, large amounts of isotopic variation were found within all diet components, with only V. thapsus exhibiting a distinct signature. In cage trials, the average delta15N and delta13C of the omnivore declined over time, coinciding with declines in total available prey, though it may be confounded by changes in temperature. The range of delta13C, but not the range of delta15N, also declined over time. This suggests a change in the plant source within the diet, but also some unquantified variability within the population. We suggest that diet variability exists within D. hesperus populations, declining as prey become less abundant.

Retrospective analysis of Healthcare Resource Group coding allocation for local anaesthetic video-assisted 'medical' thoracoscopy in a UK tertiary respiratory centre

BACKGROUND

Correct service costing is essential but may not always be done accurately.

AIM

To assess the accuracy of Healthcare Resource Group (HRG) coding allocation for patients undergoing local anaesthetic video-assisted thoracoscopy (LAVAT) against predicted codes under Payment by Results (PbR).

DESIGN

Single centre retrospective study. Tertiary respiratory centre in Leicestershire.

METHODS

One hundred twenty-five patients undergoing LAVAT from July 2005 to July 2008.

MAIN OUTCOME MEASURES

Predicted and actual revenue per LAVAT episode based on predicted and actual HRG codes allocated.

RESULTS

Among 125 patients undergoing LAVAT, the actual HRG code matched the predicted code in only 39 cases (31.2%), odds ratio (OR) 0.002, 95% confidence intervals (CIs) 0.0001-0.03, P < 0.0001. In 51 cases (40.8%), this resulted in a median (interquartile range) excess of PbR revenue of 574 pounds (574-1366) per episode; a total estimated overspend of 29,274 pounds. In 35 cases (28.0%), this resulted in a median underspend of --1093 pounds (-1285 to -851) per episode; a total estimated underspend of 38,529 pounds, with a total estimated financial error of 67,529 pounds. The net median (interquartile range) difference for PbR-related revenue was 0 pounds (-89 to + 574). Factors associated with coding discrepancy were longer length of stay (OR = 2.52, 95% CIs = 1.09-5.81, P = 0.03) and talc pleurodesis (OR = 2.25, 95% CI = 1.01-4.99, P = 0.06).

CONCLUSION

HRG coding allocation errors occur frequently. The potential financial implications of this are significant for providers and commissioners. Future strategies are required at multiple levels (NHS Trust, Primary Care Trust and Department of Health) to minimize future discrepancies and financial error.

An alpha-fetoprotein-derived peptide reduces the uterine hyperplasia and increases the antitumour effect of tamoxifen

Tamoxifen (Tam) is effective for the treatment and prevention of breast cancer. However, it has toxic drawbacks and has limited-duration utility because, over time, human tumours become refractory to Tam. Recently, a new nontoxic peptide, alpha-fetoprotein-derived peptide (AFPep) has been proposed for the treatment and prevention of breast cancer. The purpose of this paper is to determine whether combining AFPep with Tam would increase efficacy and reduce toxicity in experimental models of breast cancer. Low doses of AFPep and Tam were more effective in combination than either agent alone against breast cancer growth in cell culture, in tumour-xenografted mice, and in carcinogen-exposed rats. alpha-Fetoprotein-derived peptide interfered with Tam-induced uterine hyperplasia in immature mice, and showed no toxic effects. Unlike Tam, AFPep did not inhibit binding of oestradiol (E(2)) to oestrogen receptor (ER). Thus, these two agents utilise different mechanisms to interfere with ER functionality, yet work cooperatively to reduce breast cancer growth and alleviate Tam's troubling toxicity of uterine hyperplasia and appear to be a rational combination for the treatment of ER-positive breast cancer.

Synthetic peptide derived from alpha-fetoprotein inhibits growth of human breast cancer: investigation of the pharmacophore and synthesis optimization

Asynthetic peptide that inhibits the growth of estrogen receptor positive (ER+) human breast cancers, growing as xenografts in mice, has been reported. The cyclic 9-mer peptide, cyclo[EMTOVNOGQ], is derived from alpha-fetoprotein (AFP), a safe, naturally occurring human protein produced during pregnancy, which itself has anti-estrogenic and anti-breast cancer activity. To determine the pharmacophore of the peptide, a series of analogs was prepared using solid-phase peptide synthesis. Analogs were screened in a 1-day bioassay, which assessed their ability to inhibit the estrogen-stimulated growth of uterus in immature mice. Deletion of glutamic acid, Glu1, abolished activity of the peptide, but glutamine (Gln) or asparagine (Asn) could be substituted for Glu1 without loss of activity. Methionine (Met2) was replaced with lysine (Lys) or tyrosine (Tyr) with retention of activity. Substitution of Lys for Met2 in the cyclic molecule resulted in a compound with activity comparable with the Met2-containing cyclic molecule, but with a greater than twofold increase in purity and corresponding increase in yield. This Lys analog demonstrated anti-breast cancer activity equivalent to that of the original Met-containing peptide. Therefore, Met2 is not essential for biologic activity and substitution of Lys is synthetically advantageous. Threonine (Thr3) is a nonessential site, and can be substituted with serine (Ser), valine (Val), or alanine (Ala) without significant loss of activity. Hydroxyproline (Hyp), substituted in place of the naturally occurring prolines (Pro4, Pro7), allowed retention of activity and increased stability of the peptide during storage. Replacement of the first Pro (Pro4) with Ser maintains the activity of the peptide, but substitution of Ser for the second Pro (Pro7) abolishes the activity of the peptide. This suggests that the imino acid at residue 7 is important for conformation of the peptide, and the backbone atoms are part of the pharmacophore, but Pro4 is not essential. Valine (Val5) can be substituted only with branched-chain amino acids (isoleucine, leucine or Thr); replacement by d-valine or Ala resulted in loss of biologic activity. Thus, for this site, the bulky branched side chain is essential. Asparagine (Asn6) is essential for activity. Substitution with Gln or aspartic acid (Asp), resulted in reduction of biologic activity. Removal of glycine (Gly8) resulted in a loss of activity but nonconservative substitutions can be made at this site without a loss of activity indicating that it is not part of the pharmacophore. Cyclization of the peptide is facilitated by addition of Gln9, but this residue does not occur in AFP nor is it necessary for activity. Gln9 can be replaced with Asn, resulting in a molecule with similar activity. These data indicate that the pharmacophore of the peptide includes side chains of Val5 and Asn6 and backbone atoms contributed by Thr3, Val5, Asn6, Hyp7 and Gly8. Met2 and Gln9 can be modified or replaced. Glu1 can be replaced with charged amino acids, and is not likely to be part of the binding site of the peptide. The results of this study provide information that will be helpful in the rational modification of cyclo[EMTOVNOGQ] to yield peptide analogs and peptidomimetics with advantages in synthesis, pharmacologic properties, and biologic activity.

Gene frequencies of human platelet antigens 1-5 in indigenous Australians in Western Australia

The frequencies of human platelet antigen (HPA) systems vary between different racial groups; however, HPA frequency data for some racial groups are still incomplete. We report the distribution of HPA 1-5 systems in Australian Aborigines from a remote community in the north-west of Australia and compare our findings with HPA observed in a Western Australian blood donor population. Using a polymerase chain reaction (PCR) with sequence-specific primers, 185 indigenous Australians and 1000 Western Australian blood donors were genotyped for each of the HPA 1-5 systems. Comparison of gene frequencies of alleles from HPA-1, -2, -3 and -5 systems showed significant differences between Aboriginal people and Western Australian blood donors (P < 0.001). In particular, the frequency of HPA-3b (0.068) in the Australian Aboriginals, from this study, was one of the lowest reported, whilst the frequency of HPA-5b (0.246) was one of the highest for this allele. Gene frequencies were similar to those reported for central Australian Aborigines but with no other ethnic group. In conclusion, this study confirms significant differences in HPA distributions between indigenous Australians, Australian blood donors and other racial groups. These results indicate a higher potential risk of alloimmunization to HPA-1, -2 and -3 in Australian Aborigines receiving transfusion therapy from a Caucasian blood donor population, thereby having practical implications for transfusion and pregnancy risks in people of Aboriginal origin.

Development of a synthetic cyclized peptide derived from alpha-fetoprotein that prevents the growth of human breast cancer

The peptide, EMTPVNPG, derived from alpha-fetoprotein, inhibits estrogen-stimulated growth of immature mouse uterus and estrogen-dependent proliferation of human breast cancer cells. However, the biological activities of the peptide diminish over time in storage, even when in the lyophilized state, probably because of peptide aggregation through hydrophobic interaction among monomers. Two analogs of EMTPVNPG were designed with the intent of minimizing aggregation and retaining biological activity during prolonged storage. EMTOVNOG, where O is 4-hydroxyproline, is a linear peptide generated by substituting 4-hydroxyproline for the two prolines, thereby increasing peptide hydrophilicity. This analog exhibited a dose-dependent inhibition of estrogen-stimulated growth of immature mouse uterus similar to that of EMTPVNPG (maximal activity at 1 microg/mouse). A second analog, cyclo-(EMTOVNOGQ), a hydrophilic, cyclic analog with increased conformational constraint, was as potent as the other peptides in its inhibition of estrogen-dependent growth of immature mouse uterus, and had an expanded effective dose range. Both linear and cyclized hydroxyproline-substituted analogs exhibited indefinite shelf-life. Furthermore, both analogs inhibited the estrogen-dependent growth of MCF-7 human breast cancer growing as a xenograft in SCID mice. These analogs may become significant, novel agents for the treatment of breast cancer.

Two new loci affecting cell division identified as suppressors of an ftsQ-null mutation in Streptomyces coelicolor A3(2)

Mutations in fts genes partially or completely block both vegetative cell division and sporulation septation in the filamentous bacterium Streptomyces coelicolor A3(2). Using a novel screen, we independently isolated two double-mutant strains, each containing a spontaneous suppressor mutation, which partially restores division to an ftsQ-null mutant. Genetic complementation experiments revealed that the suppressor mutations alone confer no observable defect in sporulation. The suppressor mutations were genetically mapped to regions of the chromosome, distinct from each other and the division and cell wall cluster containing ftsQ. Therefore, the genes identified by the suppressor mutations were named sqnA and sqnB (suppressor of ftsQ-null) and may be representatives of a novel class of genes involved in cell division or the regulation of cell division in this mycelial organism.

Reducing waiting times for sleep apnoea hypopnoea syndrome and snoring using a questionnaire and home oximetry: results of a second audit cycle

As a result of a previous audit on the management of sleep apnoea hypopnoea syndrome (SAHS) which showed long waiting times that were primarily due to unnecessary interspecialty referrals, a change in practice was adopted. All referrals are now sent a questionnaire about symptoms suggestive of SAHS, the Epworth Sleepiness Scale score and their body mass index (BMI) which when returned are categorized into having a high, intermediate or low risk of SAHS. Those patients with a high probability have home overnight oximetry and those with intermediate probability have video oximetry. Those with a low probability are referred directly to ENT. We audited the first 100 patients referred. All were General Practitioner referrals to either ENT or respiratory medicine. Only two patients had a low probability score and were seen directly in ENT. Following sleep study analysis, 10 patients were referred directly to ENT with no respiratory medicine follow-up and nine were discharged back to the General Practitioner with no apnoea or snoring. Eighty-one patients were followed up by respiratory medicine. Of these, 49 received a trial of nasal continuous positive airway pressure (nCPAP) and six were referred to ENT. Therefore the majority justified an investigation to exclude SAHS in the first instance and an unnecessary initial ENT appointment was avoided. We have reduced the average waiting times to sleep study by approximately 90 days and to nCPAP trial by 32 days, mostly due to decreased delays in interspeciality referrrals. We have also demonstrated a greater than 50 per cent reduction in ENT clinic visits, a small increase in the number of sleep studies but no increase in respiratory clinic workload.

Studies on analogs of a peptide derived from alpha-fetoprotein having antigrowth properties

A 34-amino acid portion of the third domain of alpha-fetoprotein possesses antigrowth and anticancer activities. Three analogs of this sequence were chemically synthesized, in which the two cysteines of the original sequence were replaced by alanines, glycines or serines. The original cysteine and alanine peptides formed trimers at 0.20 g/L in pH 7.4 phosphate buffer, and the glycine and serine peptides formed dimers. Trimer preparations were more potent in inhibiting estrogen-induced growth in the mouse uterine assays than the two dimeric oligomers. Of salient importance is that the alanine peptide retained its trimeric form in solution much longer than the cysteine peptide. Antigrowth assays were performed starting with stock solutions at a peptide concentration of 0.20 g/L, because at very high peptide concentration (8.0 g/L) the peptides aggregated extensively. All the peptides, although differing in biological activity, had almost identical secondary structures. Unlike alpha-fetoprotein, the three peptides have low amounts of alpha-helix. Trifluoroethanol has the ability to convert peptides into a helical conformation when they have a propensity for that structure. At trifluoroethanol concentrations of 20% and higher, the alanine and glycine peptides were changed into highly helical structures.

A pilot study of rapid lithium administration in the treatment of acute mania

OBJECTIVES

The use of rapid lithium dosage administration, a strategy that could lead to rapid improvement in mania, has been largely unexamined. In this open-label, pilot, acute-treatment study, we sought to determine the safety and tolerability of lithium administered at 20 mg/ kg/day. A secondary aim was to provide preliminary data regarding the efficacy of this strategy in ameliorating manic, depressive, and psychotic symptoms.

METHODS

Fifteen patients hospitalized with DSM-IV bipolar disorder, manic or mixed, and who provided written informed consent, received lithium 20 mg/kg/day for up to 10 days. Patients were evaluated for adverse effects daily. Lithium levels were obtained on days 2, 3, 4, 5, 7, and 10 or at study termination. Electrocardiograms (EKGs) were performed at baseline and on days 1-5, 7, and 10 or at study termination. Symptomatic improvement was assessed daily using the Young Mania Rating Scale, 24-item Hamilton Depression Rating Scale, and the Scale for Assessment of Positive Symptoms (SAPS).

RESULTS

Five of the 15 patients completed the 10-day study period. Two patients dropped out due to adverse events. Seven patients did not complete the inpatient trial because of improvement sufficient to allow hospital discharge. All patients achieved serum lithium concentrations > or =0.6 mEq/L after 1 day of treatment; the mean + SD concentration on day 5 was 1.1 (+/- 0.1) mEq/L on day 5. There were significant reductions from baseline to endpoint on all rating scales, except the SAPS bizarre behavior subscale.

CONCLUSIONS

These pilot data suggest that lithium 20 mg/kg/day was well tolerated and that this strategy may produce rapid improvement in affective and psychotic symptoms. These impressions require confirmation in double-blind, randomized trials.

Valproate as a loading treatment in acute mania

Evidence from earlier studies indicates that the antimanic action of valproate becomes most apparent within 1-4 days of achieving serum concentrations 50 micrograms/ml, that valproate can be orally loaded with achievement of therapeutic serum concentrations within the first several days of treatment, there is a rapid onset of response, and minimal side effects. To provide further data on the safety and efficacy of valproate oral loading in the treatment of acute mania, we evaluated 13 consecutive patients with acute manic syndromes who received valproate initiated at a dosage of 20 mg/kg/day. In most cases, valproate was added to other psychotropics. All 13 patients received at least 5 full days of valproate maintained at or above 20 mg/kg/day, and valproate serum concentrations were 50 micrograms/ml (mean +/- SD = 88 + 25) by the second or third day of treatment. Ten (77%) patients displayed a moderate or marked response. Side effects were infrequent and minor. Consistent with our earlier study, these findings suggest that valproate can be safely administered via a loading dose of 20 mg/kg/day to patients with acute mania, including those on other psychotropics, and that it may produce a rapid response with minimal side effects.

Health-economic implications of the onset of action of antimanic agents

BACKGROUND

Three medications, lithium, valproate, and carbamazepine, have been shown to be effective in the treatment of acute mania in randomized, controlled clinical trials. Additional research over the past decade has provided data regarding potential differences between these medications according to their time course of onset and clinical predictors of response in acute mania. These differences have potential impact on both the choice of medication and the health-economics of the treatment of acute mania.

METHOD

Published reports regarding the time course of onset, clinical factors associated with response, and health-economic impact of the treatment of acute mania with lithium, valproate, and carbamazepine were reviewed (PAPERCHASE data base, 1966 to present, terms: bipolar disorder, drug treatment, lithium, valproate, and carbamazepine).

RESULTS

Valproate, when administered via an oral loading dosage, may have a more rapid onset of action than lithium and carbamazepine. Preliminary data suggest that specific clinical factors associated with response differ between the three medications. Health-economic studies suggest that treatment of acute mania with valproate may be associated with greater cost savings due to shorter lengths of hospital stay, particularly in patients with mixed mania and rapid cycling. Patients treated with the combination of carbamazepine and lithium also had reduced hospital lengths-of-stay in one study. Lithium may have greater cost savings in patients with classic mania.

CONCLUSION

Preliminary data from studies reviewed suggest that important differences exist between lithium, valproate, and carbamazepine in their time course of onset and factors associated with response in the treatment of patients with acute mania. These differences may also impact the cost savings associated with treatment with these agents.

Antiepileptic drugs for the treatment of panic disorder

Evidence from preclinical studies, preliminary clinical reports, pharmacologic challenge studies and a small number of controlled trials suggests that several antiepileptic agents--valproate, carbamazepine, and clonazepam--may have therapeutic effects in the treatment of patients with panic disorder. We review the theoretical basis and available clinical data supporting the use of these agents in panic disorder.

War, emergency and the environment: Fiji, 1939-1946

When World War Two broke out, Fiji's colonial administration assumed emergency powers to marshal the civilian population to produce goods and services for the war effort, particularly the support of American and New Zealand military personnel based there during 1942-43. This context of emergency framed land legislation revision, enabling the government at times to deal in a high-handed manner in resuming Fijian leased land for native reserves, mainly from Indian tenants. The added population and wartime construction placed extensive demands on Fiji's resources, inducing environmental changes. The government as well as the various racial groups in Fiji were largely unconcerned with this unless the degradation was obvious, threatening the well-being of the human population.

Studies on a growth-inhibitory peptide derived from alpha-fetoprotein and some analogs

A 34-amino acid synthetic peptide was derived from the third domain of human alpha-fetoprotein, and the peptide was shown to inhibit estrogen-stimulated growth. Under certain conditions, however, the peptide lost growth-inhibitory activity. A biophysical study of the peptide was undertaken with a goal of obtaining completely reliable preparations. The peptide was studied using gel-filtration column chromatography as a function of peptide concentration and age of solution, and was found to exhibit complex aggregation behaviors. During the early period (0-3 h) after dissolving lyophilized peptide into pH 7.4 buffer, solutions were composed mostly of trimers. At higher peptide concentrations (> or = 3.0 g/L), the trimers aggregated extensively to a large aggregate (minimum size approximately 102 peptides). At 5.0-8.0 g/L, these large aggregates increased in size (up to approximately 146 peptides) until trimers were largely exhausted from solution. During the later times (>3 h) after sample preparation, the trimeric oligomer of the peptide dissociated slowly to form dimers for samples at 0.10-3.0 g/L. After their build-up, a very small number of dimers associated to form hexamers. Disulfide bonds stabilized the dimers as indicated by the conversion of dimers to trimers upon the addition of a reducing agent, and the failure of dimers to form in the presence of reducing agent. Reducing agent did not affect trimer or large aggregate formation. Trimers were found to be active in an assay monitoring inhibition of estrogen-stimulated growth, whereas dimers and large aggregates were inactive. The two cysteines in the peptide were modified to either S-methylcysteine or S-(2-aminoethyl)cysteine, and both derivatives showed significant growth-inhibition activity. A serine analog in which both cysteines were replaced had very different aggregation behavior than the cysteine peptide and lacked its growth inhibitory ability. Peptide aggregation is critically important in establishing the ability of the peptide to inhibit growth and have anticancer activity, but the state of its two cysteines is of little influence.

Mediator and moderator variables in nursing research: conceptual and statistical differences

Mediators and moderators are variables that affect the association between an independent variable and an outcome variable. Mediators provide additional information about how or why two variables are strongly associated. In contrast, moderators explain the circumstances that cause a weak or ambiguous association between two variables that were expected to have a strong relationship. Mediators and moderators are often overlooked in research designs, or the terms are used incorrectly. This article summarizes the conceptual differences between mediators and moderators. The statistical analysis of moderators and mediators in multiple regression is briefly described and two examples are presented.

Alpha-fetoprotein-derived antiestrotrophic octapeptide

Alpha-fetoprotein (AFP) is a major serum protein produced during fetal development. Experimental findings suggest that AFP has antiestrotrophic activity and that it can be developed as a therapeutic agent to treat existing estrogen-dependent breast cancer or to prevent premalignant foci from developing into breast cancer. The antiestrotrophic activity of AFP was reported to be localized to a peptide consisting of amino acids 447-480, a 34-mer peptide termed P447. A series of parsings and substitutions of amino acids in the P447 sequence was intended to identify the shortest analog which retained antiestrotrophic activity. Peptides related to P447 were generated using solid phase peptide synthesis. Several shorter peptides, including an 8-mer called P472-2 (amino acids 472-479, peptide sequence EMTPVNPG), retained activity, whereas peptides shorter than eight amino acid residues were inactive. The dose-related antiestrotrophic activity of AFP-derived peptides was determined in an immature mouse uterine growth assay that measures their ability to inhibit estradiol-stimulated uterine growth. In this assay, the maximal inhibitory activities exhibited by peptide P472-2 (49%), by peptide P447 (45%), and by intact AFP (35-45%) were comparable. The octapeptide P472-2 was also active against estradiol-stimulated growth of T47D human breast cancer cells in culture. These data suggest that peptide P472-2 is the minimal sequence in AFP, which retains the antiestrotrophic activity found with the full-length molecule. The synthetic nature and defined structure of this 8-mer peptide suggest that it can be developed into a new drug which opposes the action of estrogen, perhaps including the promotional effects of estradiol in the development of human breast cancer.

Dehydration: hazards and benefits

Dehydration is a serious risk for elders because total body water decreases with age, aging kidneys are less able to concentrate urine, and the sensation of thirst decreases. Geriatric nurses traditionally have assessed for dehydration, but its signs are difficult to detect in many patients. Instead, nurses, assistive personnel, and family members must work to prevent dehydration in elders. In contrast, dehydration may be beneficial to patients during the final stage of a terminal illness, although the decision to withhold or withdraw medical hydration may present a legal and ethical dilemma for nurses.

Pharmacologic loading in the treatment of acute mania

The rapid and safe reduction of manic symptoms is an important initial goal of the pharmacologic treatment of acute mania. The pharmacokinetics and studies of pharmacologic loading of lithium, valproate, and carbamazepine were reviewed. In addition, the feasibility of administering other agents with potential efficacy in mania, e.g., atypical antipsychotics and new anticonvulsants, was discussed. Further double-blind, controlled studies with adequate sample sizes comparing loading strategies with more gradual titration schedules of candidate antimanic agents are needed.

Scintigraphic detection of breast cancer xenografts with Tc-99m natural and recombinant human alpha-fetoprotein

Because adenocarcinoma of the breast expresses receptors for alpha-fetoprotein (AFP), we studied Tc-99m AFP as a radiopharmaceutical to detect breast cancer. The biodistribution of Tc-99m radiolabeled natural human AFP (full length) and recombinant domain III (DIII) of human AFP was compared to Tc-99m sestamibi and Tl-201 in a murine model of human breast cancer. Estrogen receptor positive (MCF7, T-47D) and estrogen receptor negative (MDA-MB-231, BT-20) human breast cancer xenografts were grown subcutaneously in the lateral thorax region of immunosuppressed mice (ICR SCID). Quantitative comparisons of percent-injected dose per gram of tissue (%ID/gram) and tumor to thigh ratio (T/Th) were performed at 0-60 minutes and at 24 hours following injection. For most tumors, T/Th for AFP and DIII was significantly greater than T/Th for Tc-99m sestamibi and Tl-201. In all breast cancers (BT-20, MCF7, MDA-MB-231, T-47D), Tc-99m AFP T/Th increased from 60 minutes to 24 hours, suggesting good tumor retention of this radiopharmaceutical. DIII and AFP had significantly higher %ID/gram than either Tl-201 or Tc-99m sestamibi when considered across all tumor types at both 60 minutes and 24 hours. The data suggests that localization of Tc-99m AFP in human breast cancer xenografts is initially rapid, increases with time, and is superior to Tc-99m sestamibi and Tl-201. Given its high uptake by breast cancer cells, its low non-tumor localization and its rapid renal excretion, these Tc-99m AFP preparations may be useful agents to detect human breast carcinoma.

Parent to parent: preventing adolescent exposure to HIV

A 2-year pilot program implemented by public health nurses (PHNs) in partnership with the leaders of parent associations of 10 urban high schools encouraged communication about health-promoting sexual behavior between adults and adolescents. The purpose was to assess the feasibility of involving parents in health promotion efforts in schools. During the first year, PHNs prepared a cohort of 17 parent trainers to make presentations to parent groups about the reality of teens' risk for human immunodeficiency virus (HIV) exposure, facts to counter myths about outcomes of sex education, and the skills teens need to implement healthy choices, including abstinence, correct condom use, and talking about sex with a potential sexual partner. Each parent trainer was then scheduled to make two presentations at parent association meetings. Criteria for assessing the impact of extending the program, including broader diffusion in the community, are proposed. This approach may be effective for community-based education about other health issues.

Time dependence of anodal and cathodal refractory periods in cardiac tissue

Mehra et al. (PACE 1980; 3:526) observed that immediately after implantation of a pacing electrode in a dog heart, the anodal refractory period (RP) is shorter than the cathodal RP, but after several weeks the anodal RP becomes longer than the cathodal RP. We examine this experiment using numerical simulations based on the bidomain model of cardiac tissue and a Beeler-Reuter membrane. Our hypothesis is that accumulation of inexcitable tissue around the electrode following implantation causes the effective size of the electrode to increase and that this increase is the mechanism underlying the change in RP. We calculate that the anodal RP is shorter than the cathodal RP for both large and small electrodes. However, for large electrodes the threshold for anode "break" stimulation is greater than 8 mA. Mehra et al. defined RP experimentally as the interval at which the threshold stimulus strength becomes greater than 8 mA. If we restrict the stimulus current in our calculations to less than 8 mA, we exclude anode break stimulation from our calculation of the RP. In that case, our results are consistent with Mehra et al. and suggest that their observation resulted from their definition of RP.

Activities of daily living. Old-fashioned or still useful?

1 The Index of Activities of Daily Living (ADL) is used by many nurses to assess function in older adults, but there is debate regarding the scoring, wording of questions, and validity in diverse populations. 2 Older adults may give inaccurate answers to ADL questions because they misunderstand the questions, have personal reasons for underreporting or overreporting difficulty in ADL, or fail to recognize difficulty because they have adapted to changes in function. 3 Physical performance tests, especially of the lower extremities, may be an alternative method of assessing function, especially in high-functioning older adults who report no difficulty in ADL.

The recombinant third domain of human alpha-fetoprotein retains the antiestrotrophic activity found in the full-length molecule

Previous studies have shown that alpha-fetoprotein (AFP) interferes with estrogen (E2)-stimulated growth, including E2-stimulated breast cancer growth. In an effort to localize the antiestrotrophic portion of the molecule, the C-terminal one-third (200 amino acids) of human AFP, known as Domain III, was produced in a baculovirus expression system as a fusion protein containing an amino terminal histidine tag. The histidine tag was included to facilitate purification by metal ion affinity chromatography. The purified recombinant Domain III fusion protein was functionally similar to full-length natural AFP isolated from human cord sera or from cultured human hepatoma cells (HepG2) in that they all produced significant and quantitatively similar inhibition of E2-stimulated growth of immature mouse uterus. Furthermore, the dose-response profiles of the recombinant Domain III AFP and natural full-length AFP were similar. Preincubation of either protein in a molar excess of E2 lowered the minimally effective antiestrotrophic dose and produced a difference spectrum consistent with a change in conformation. These findings indicate that the antiestrotrophic activity of AFP is contained within the third domain of the molecule, and they have obvious implications for the production of biologically active peptides derived from this portion of the AFP molecule.

The contribution of the swallowed fraction of an inhaled dose of salmeterol to it systemic effects

Salmeterol is approximately eight times as potent as salbutamol for systemic effects. This may be because the drug is eight times more potent on receptors or there may be differences in systemic bioavailability. The systemic effects of salbutamol are limited by its fairly high first-pass metabolism, but the oral bioavailability of salmeterol is unknown. The contribution of the swallowed fraction of an inhaled dose of salmeterol to its systemic effects were analysed in a randomized, double-blind, crossover study. Twelve healthy subjects were given inhaled salmeterol 400 microg, inhaled salmeterol 400 microg plus oral activated charcoal or inhaled placebo plus oral activated charcoal on three separate days. Cardiac frequency (fC), Q-T interval corrected for heart rate (QTc), plasma potassium and glucose concentrations were measured for 4 h following the inhaled drug. Salmeterol with and without oral charcoal produced significant changes for all measures compared to placebo. The magnitude of effect following salmeterol alone was significantly greater than that following salmeterol plus charcoal for fC and glucose (mean (95% confidence interval) differences 8 (2-13) beats x min(-1), 0.59 (0.04, 1.13) mmol x L(-1), respectively) and nonsignificantly greater for QTc interval and potassium concentration. The differences between salmeterol given with and without charcoal suggest that 28-36% of the systemic response to salmeterol administered from a metered-dose inhaler are due to drug absorbed from the gastrointestinal tract. Thus, most of the systemic effects are due to the inhaled fraction of the drug.

Dependence of cardiac strength-interval curves on pacing rate

The purpose of the research is to determine how the pacing rate affects the strength-interval curve in cardiac tissue. Computer simulations are used to calculate the cathodal and anodal strength-interval curves. The tissue is represented by the bidomain model with Beeler-Reuter membrane properties. The strength-interval curves shift to shorter intervals as the pacing rate increases. However, the shape of the strength-interval curve, including the separation into 'make' and 'break' sections and the presence of a 'dip', is insensitive to pacing rate.

Alpha-fetoprotein derived from a human hepatoma prevents growth of estrogen-dependent human breast cancer xenografts

Alpha-fetoprotein (AFP) is a transport protein that has growth-regulatory properties in many different tissues. It is known to interfere with responses stimulated by estrogen. The purpose of this study was to determine whether human AFP would inhibit the growth of human breast cancer. AFP was isolated from the culture supernatant of human hepatoma cells (HepG2) grown in serum-free medium and was purified by immunoaffinity chromatography. Human breast cancers were grown as xenografts under the kidney capsule of severe combined immunodeficient mice. The minimum inhibitory dose of AFP against estradiol (E2)-stimulated growth of human MCF-7 breast cancer xenografts was 10 microg/mouse/day, and maximum inhibition (no growth) was achieved with 100 microg/mouse/day. Daily treatment was required to sustain inhibition. This 100-microg dose of AFP also inhibited xenograft growth of E2-dependent T47 human breast carcinoma. Estrogen receptor-negative MDA MB 231 and BT20 human breast carcinoma xenografts were not inhibited by AFP (100 microg/mouse/day). Elevation in serum E2 occurred during AFP treatment. AFP did not compete with agonists for the estrogen receptor. These laboratory results are consistent with the findings of a literature search, which consistently showed an association between elevated pregnancy levels of AFP and subsequent reduced risk for breast cancer later in life. We conclude that AFP can inhibit growth of estrogen-dependent breast cancer and warrants further development as an agent for the treatment and perhaps even the prevention of human breast cancer.