Using hydraulic head measurements in variable-density ground water flow analyses

The use of hydraulic head measurements in ground water of variable density is considerably more complicated than for the case of constant-density ground water. A theoretical framework for dealing with these complications does exist in the current literature but suffers from a lack of awareness among many hydrogeologists. When corrections for density variations are ignored or not properly taken into account, misinterpretation of both ground water flow direction and magnitude may result. This paper summarizes the existing theoretical framework and provides practical guidelines for the interpretation of head measurements in variable-density ground water systems. It will be argued that, provided that the proper corrections are taken into account, fresh water heads can be used to analyze both horizontal and vertical flow components. To avoid potential confusion, it is recommended that the use of the so-called environmental water head, which was initially introduced to facilitate the analysis of vertical ground water flow, be abandoned in favor of properly computed fresh water head analyses. The presented methodology provides a framework for determining quantitatively when variable-density effects on ground water flow need to be taken into account or can be justifiably neglected. Therefore, we recommend that it should become part of all hydrogeologic analyses in which density effects are suspected to play a role.

Alterations in calcium metabolism in patients on long-term bisphosphonate therapy for metastatic breast cancer (MBC): A potential therapeutic target?

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Background: The effect of long-term potent BP use on calcium homeostasis in MBC pts is poorly understood. These effects and the need for calcium and Vitamin D supplementation may have significant implications for pt management in both the metastatic and adjuvant settings. Methods: We evaluated serum calcium (sCa), PTH, and 25(OH)D levels and their inter-relationships in 30 MBC pts after prolonged BP use for bone metastases (BM), compared with a control group (CG) of 1484 normal women without bone or mineral disease (JCEM 2003;88:185). The MBC pts were prescribed oral calcium (1g/d) and vitamin D (400IU/d) for 1 month prior to analysis. To determine whether MBC pts differed from CG with respect to the sCa-PTH correlation, logistic regression was performed with sCa, log-transformed PTH and an interaction term (Ca × lnPTH). Results: Mean age of the two groups did not differ [MBC group (58.5 ± 2.0 yr) vs. CG (55.2 ± 0.4 yr, p >.05)]. VitD-deficiency (25vitD < 40 nM) was equally prevalent in the two groups [MBC (23%) vs. CG (25%)]. sCa was significantly higher in MBC pts (2.473 ± 0.019 mM) compared to CG (2.377 ± 0.003, p <0.001). However, PTH was not decreased in MBC pts (4.60 ± 0.36 pM), compared to CG (4.56 ± 0.06, t-test, p=0.91). Logistic regression was highly significant (p<0.0001), as were coefficients for both explanatory variables (sCa, p <0.0001 and lnPTH, p = 0.009) and their interaction (p=0.011). Conclusion: In pts with BM and prolonged BP use there appears to be a shift in the calcium set-point such that PTH release is activated by higher levels of sCa than in controls. We are currently studying whether prophylaxis for relative vit D deficiency in this population can not only correct this shift but also improve pt symptoms

No significant financial relationships to disclose.

Changes in estrogen receptor (ER), progesterone receptor (PR) and HER2/neu status with time: Discordance rates between primary and metastatic breast pathology samples

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Background: The occurrence of changes in tumor receptor profile (ER, PR and HER-2/neu) between primary and metastatic tissue has been recognised and may have significant treatment implications. Previous reports on receptor discordance rates have tended to be from sub-studies of clinical trials. We sought to evaluate the degree of ER, PR and HER-2/neu receptor discordance in patients treated at two Canadian cancer centres. Methods: Archival data was collected on patients for whom tissue from both primary and metastatic sites was available. Patients with recurrences in the breast or axilla were excluded. ER, PR and HER-2/neu status in the primary and metastasis were compared. Additional information including adjuvant therapy and time to metastasis biopsy was gathered. Results: To date, data is available on 80 patients. Hormone receptor (HR) status was available for 96% of primaries and 56% of metastases. HR status on both the primary and the metastasis was performed in 51% of cases. The discordance rate for ER was 21% (2-sided p=0.0096). 12% of patients changed from ER+ to ER- and 9% changed from ER- to ER+. The discordance rate for PR was 37% (2-sided p=0.0001), with all of these patients changing from PR+ to PR-. No significant HR discordance was found among different adjuvant hormone therapy subgroups. There was no correlation between HR discordance and time to rebiopsy. No discordance for HER-2/neu was found. Conclusions: Significant discordance for HR status was observed, 21% for ER and 37% for PR. HER-2/neu discordance was not observed. We are currently exploring the practical implications of these discordance rates on the management of advanced breast cancer patients in a prospective trial.

No significant financial relationships to disclose.

A practical guide to the management of menopausal symptoms in breast cancer patients

Breast cancer is the most frequently diagnosed cancer in Canadian women. As a result of increased screening and improved treatment, more women are becoming long-term breast cancer survivors. However, due to either their treatment or prolonged survival, many of these women now have to face the consequences of premature menopause and prolonged estrogen deprivation. Hormone replacement therapy/estrogen replacement therapy (HRT/ERT) has, in the past, been recommended to healthy women at menopause not only for relief of short-term menopausal changes, particularly hot flashes, but also for its benefits on bone density, fracture reduction, and genitourinary symptoms. Recent studies have demonstrated that not only is HRT associated with an increased risk of developing breast cancer, but it also has been shown to increase the risk of recurrence in those with a breast cancer history. Until the safety of HRT/ERT in breast cancer patients can be more fully clarified, it would be wise to develop alternative strategies for the management of menopausal symptoms in these patients. This paper will discuss nonestrogen-based therapies for hot flashes, osteoporosis, and genitourinary symptoms, with emphasis on efficacy and safety in breast cancer survivors.

Bone regeneration in a rat cranial defect with delivery of PEI-condensed plasmid DNA encoding for bone morphogenetic protein-4 (BMP-4)

Gene therapy approaches to bone tissue engineering have been widely explored. While localized delivery of plasmid DNA encoding for osteogenic factors is attractive for promoting bone regeneration, the low transfection efficiency inherent with plasmid delivery may limit this approach. We hypothesized that this limitation could be overcome by condensing plasmid DNA with nonviral vectors such as poly(ethylenimine) (PEI), and delivering the plasmid DNA in a sustained and localized manner from poly(lactic-co-glycolic acid) (PLGA) scaffolds. To address this possibility, scaffolds delivering plasmid DNA encoding for bone morphogenetic protein-4 (BMP-4) were implanted into a cranial critical-sized defect for time periods up to 15 weeks. The control conditions included no scaffold (defect left empty), blank scaffolds (no delivered DNA), and scaffolds encapsulating plasmid DNA (non-condensed). Histological and microcomputed tomography analysis of the defect sites over time demonstrated that bone regeneration was significant at the defect edges and within the defect site when scaffolds encapsulating condensed DNA were placed in the defect. In contrast, bone formation was mainly confined to the defect edges within scaffolds encapsulating plasmid DNA, and when blank scaffolds were used to fill the defect. Histomorphometric analysis revealed a significant increase in total bone formation (at least 4.5-fold) within scaffolds incorporating condensed DNA, relative to blank scaffolds and scaffolds incorporating uncondensed DNA at each time point. In addition, there was a significant increase both in osteoid and mineralized tissue density within scaffolds incorporating condensed DNA, when compared with blank scaffolds and scaffolds incorporating uncondensed DNA, suggesting that delivery of condensed DNA led to more complete mineralized tissue regeneration within the defect area. This study demonstrated that the scaffold delivery system encapsulating PEI-condensed DNA encoding for BMP-4 was capable of enhancing bone formation and may find applications in other tissue types.

In vivo degradation of 14C-labeled small intestinal submucosa (SIS) when used for urinary bladder repair

The rate of in vivo degradation was determined for a naturally occurring biomaterial derived from the extracellular matrix of the small intestinal submucosa (SIS). The SIS was labeled by giving weekly intravenous injections of 10 microCi of 14C-proline to piglets from 3 weeks of age until the time of sacrifice at 26 weeks. The resultant SIS prepared from these pigs contained approximately 10(3) fold more 14C than unlabeled tissues. The labeled SIS was used to repair experimental defects in the urinary bladder of 10 dogs. The animals were sacrificed at post-operative times ranging from 3 days to 1 year and the remodeled urinary bladder tissue was harvested for evaluation of 14C by a combination of liquid scintillation counting and accelerator mass spectrometry. The remodeled tissue contained less than 10% of the 14C (disintegrations per minute/gram tissue wet weight) at 3 months post-surgery compared to the SIS biomaterial that was originally implanted. The SIS scaffold was replaced by host tissue that resembled normal bladder both in structure and function. After implantation, 14C was detected in highest concentrations in the blood and the urine. The SIS bioscaffold provides a temporary scaffold for tissue remodeling with rapid host tissue remodeling, degradation, and elimination via the urine when used as a urinary bladder repair device.

Season-of-birth bias in association football

In this longitudinal study, we assessed the frequency of birth dates for boys selected for the Football Association National School. Birthdays were divided into three periods of the year: January to April, May to August and September to December. We compared data over a 5 year period and concluded that there is indeed a bias towards selecting older children. Furthermore, analysis of separate data revealed a shift of bias when comparing two different start dates, namely September and January. Our findings show that the youngest children from the January start date (born September to December) are selected significantly more often than the youngest children from the September start date (born May to August). Interestingly, even when the influence of body mass was reduced, the selection bias towards the older players remained.

Refocusing of B-cell responses following a single amino acid substitution in an antigen

Intranasal immunization of BALB/c strain mice was carried out using baculovirus-derived human chorionic gonadotrophin (hCG) beta-chain, together with Escherichia coli heat-labile enterotoxin. Gonadotrophin-reactive immunoglobulin A (IgA) was induced in a remote mucosal site, the lung, in addition to a systemic IgG response. The extensive sequence homology with luteinizing hormone (LH) results in the production of LH cross-reactive antibodies when holo-hCG is used as an immunogen. In contrast to wild-type hCGbeta, a mutated hCGbeta-chain containing an arginine to glutamic acid substitution at position 68 did not induce the production of antibodies which cross-react with LH. Furthermore, the epitopes utilized in the B-cell response to the mutated hCGbeta shifted away from the immunodominant region of the parent wild-type molecule towards epitopes within the normally weakly immunogenic C terminus. This shift in epitope usage was also seen following intramuscular immunization of rabbits. Thus, a single amino acid change, which does not disrupt the overall structure of the molecule, refocuses the immune response away from a disadvantageous cross-reactive epitope region and towards a normally weakly immunogenic but antigen-unique area. Similar mutational strategies for epitope-refocusing may be applicable to other vaccine candidate molecules.

The immune responses to bacterial antigens encountered in vivo at mucosal surfaces

Mammals have evolved a sophisticated immune system for handling antigens encountered at their mucosal surfaces. The way in which mucosally delivered antigens are handled influences our ability to design effective mucosal vaccines. Live attenuated derivatives of pathogens are one route towards the development of mucosal vaccines. However, some molecules, described as mucosal immunogens, are inherently immunogenic at mucosal surfaces. Studies on mucosal immunogens may facilitate the identification of common characteristics that contribute to mucosal immunogenicity and aid the development of novel, non-living mucosal vaccines and immunostimulators.

"Modern marriage" for African Americans, 1920-1940

Between January 1925 and June 1926 the New York Messenger ran a serialized romance story entitled “The Letters of Davy Carr.” The story, set in Washington, DC, centres on the youngest daughter of the middle-class Rhodes family. Caro­line Rhodes, a grade-school teacher and a dark and lively beauty with “all the best and worst points of the modern flapper,” alternately fascinates and horrifies the priggish narrator, Davy Carr (Anonymous, Jan. 1925 26). Carr purports to be a well-educated twenty-something man, native of a “little provincial Southern city,” sojourning in Washington, DC, in 1922 to do research for a book on the slave trade. While boarding with the Rhodeses, Carr writes letters to a his war buddy back in New York, describing “colored society” in the nation’s capital, with a focus on the fascinating Caroline (Mar. 1925 146; Apr. 1925 165). Fussed over by her “Victorian” mother and elder sister, Caroline smokes and constantly visits Carr’s room to chat. He describes how she sat in his room, swinging her silk-clad legs with the abandon of a small boy, and regaled [him] in terms piquant and interesting, if a trifle startling at times, with her very mod­ern views of the woman question, fellows, and marriage … it was decidedly refreshing, but I am not sure that it was not more shocking than anything else. (Jan. 1925 27)

Igh-6(-/-) (B-cell-deficient) mice fail to mount solid acquired resistance to oral challenge with virulent Salmonella enterica serovar typhimurium and show impaired Th1 T-cell responses to Salmonella antigens

In the present study we evaluated the role of B cells in acquired immunity to Salmonella infection by using gene-targeted B-cell-deficient innately susceptible mice on a C57BL/6 background (Igh-6(-/-)). Igh-6(-/-) mice immunized with a live, attenuated aroA Salmonella enterica serovar Typhimurium vaccine strain showed impaired long-term acquired resistance against the virulent serovar Typhimurium strain C5. Igh-6(-/-) mice were able to control a primary infection and to clear the inoculum from the reticuloendothelial system. However, Igh-6(-/-) mice, unlike Igh-6(+/+) C57BL/6 controls, did not survive an oral challenge with strain C5 at 4 months after vaccination. Transfer of immune serum did not restore resistance in Igh-6(-/-) mice. Total splenocytes and purified CD4(+) T cells obtained from Igh-6(-/-) mice 4 months after vaccination showed reduced ability to release Th1-type cytokines (interleukin 2 and gamma interferon) upon in vitro restimulation with serovar Typhimurium soluble cell extracts compared to cells obtained from Igh-6(+/+) C57BL/6 control mice. Therefore, the impaired resistance to oral challenge with virulent serovar Typhimurium observed in B-cell-deficient mice, which cannot be restored by passive transfer of Salmonella-immune serum, may be in part due to a reduced serovar Typhimurium-specific T-cell response following primary immunization.

Measuring quality in hospitals: is there a difference between for-profits and not-for-profits?

Health care professionals agree that by measuring quality, improvements can be made in care delivery. There are measurable differences between not-for-profit and for-profit hospitals, both in public perception and care outcomes. The ability by consumers, insurers and providers to easily access quality data will drive the health care industry to take a quality focus in their daily business. Quality providers with measurable results will gain a larger share of health care dollars and consumer trust. Physicians will choose to partner with the quality leaders and will refine their practices as part of the quality evolution.

A phase I and pharmacological study of protracted infusions of crisnatol mesylate in patients with solid malignancies

This Phase I and pharmacological study was performed to assess the feasibility of administering the polycyclic aromatic hydrocarbon crisnatol in increasingly prolonged continuous i.v. infusions to patients with advanced solid malignancies. The study also sought to characterize the-principal toxicities of crisnatol on this schedule, to recommend doses for subsequent disease-directed studies, and to characterize possible associations between pharmacological parameters and toxicity. Sixteen patients were treated with 40 courses of crisnatol administered as a continuous i.v. infusion. The initial dose-schedule was 750 mg/m2/day for 6 days, and the duration of the infusion was to be progressively increased by 3-day increments to 9, 12, 15, 18, and 21. Courses were to be repeated every 4 weeks. Moderate to severe central nervous system (CNS) toxicity precluded the administration of crisnatol 750 mg/m2/day for longer than 6 days, and, therefore, the dose of crisnatol was reduced to 600 mg/m2/day. At this dose, three of five patients receiving a 12-day infusion experienced dose-limiting toxicity, which consisted of pulmonary thromboembolism (two patients) and grade 4 thrombocytopenia (one patient). None of the six patients completing a 9-day infusion at 600 mg/m2/day developed dose-limiting toxicity during the first or second course of crisnatol. At this dose level, the plasma concentrations at steady state (Css) averaged 1607.8+/-261.1 ng/ml, which exceeds minimal inhibitory concentrations for most tumors in vitro (1000 ng/ml). In fact, the administration of crisnatol at a dose of 600 mg/m2/day for 9 days resulted in the longest duration that biologically relevant plasma crisnatol concentrations have been sustained. Plasma Css values were significantly higher in patients who experienced severe CNS toxicity compared with those who did not (2465.3+/-1213.5 versus 1342+/-447.3 ng/ml; P = 0.04). There were no relationships evident between the clearance of crisnatol and indices reflecting renal and hepatic functions. One patient with a glioblastoma multiforme experienced a partial response lasting 14 months. The relative lack of intolerable CNS toxicity at the recommended dose for Phase II studies of crisnatol, 600 mg/m2/day for 9 days, as well as the magnitude of the Css values achieved and the antitumor activity observed at this dose, are encouraging. However, the mechanisms for the apparently increased thrombogenicity observed in this trial are unclear and require further elucidation.

Interferon-alpha upregulates gene expression of aquaporin-5 in human parotid glands

Aquaporins are a family of homologous membrane proteins that function as highly selective water channels. Aquaporin-5 (AQP5) is uniquely present in lacrimal and salivary glands, where it accounts for normal tear and saliva production. We tested the hypothesis that orally administered human interferon-alpha (HuIFN-alpha) benefits persons with xerostomia by augmenting the production of AQP5 protein by parotid gland epithelium. Cells from three human parotid glands were cultured with and without human lymphoblastoid IFN-alpha, and assayed for AQP5 mRNA levels by reverse transcriptase polymerase chain reaction (RT-PCR), and AQP5 protein levels by Western blot. Intracellular localization of AQP5 protein was done using confocal microscopy. The functional integrity of the glandular tissue was confirmed by RT-PCR analysis of alpha-amylase 1 and basic proline-rich protein transcripts. AQP5 was constitutively expressed in human parotid gland tissue, with AQP5 protein restricted to the plasma membranes and cytoplasmic vesicles of acinar cells. IFN-alpha augmented AQP5 transcription and protein production in a concentration-dependent manner, and increased the size of intensity of staining of AQP5-containing cytoplasmic vesicles in acinar cells. We conclude that IFN-alpha upregulates AQP5 gene expression in human parotid acinar cells in vitro. To our knowledge, this is the first demonstration that IFN-alpha regulates the gene expression of an aquaporin.