Steroidal lactones from Withania somnifera effectively target Beta, Gamma, Delta and Omicron variants of SARS-CoV-2 and reveal a decreased susceptibility to viral infection and perpetuation: a polypharmacology approach

Prevention from disease is presently the cornerstone of the fight against COVID-19. With the rapid emergence of novel SARS-CoV-2 variants, there is an urgent need for novel or repurposed agents to strengthen and fortify the immune system. Existing vaccines induce several systemic and local side-effects that can lead to severe consequences. Moreover, elevated cytokines in COVID-19 patients with cancer as co-morbidity represent a significant bottleneck in disease prognosis and therapy. Withania somnifera (WS) and its phytoconstituent(s) have immense untapped immunomodulatory and therapeutic potential and the anticancer potential of WS is well documented. To this effect, WS methanolic extract (WSME) was characterized using HPLC. Withanolides were identified as the major phytoconstituents. In vitro cytotoxicity of WSME was determined against human breast MDA-MB-231 and normal Vero cells using MTT assay. WSME displayed potent cytotoxicity against MDA-MB-231 cells (IC50: 66 µg/mL) and no effect on Vero cells in the above range. MD simulations of Withanolide A with SARS-CoV-2 main protease and spike receptor-binding domain as well as Withanolide B with SARS-CoV spike glycoprotein and SARS-CoV-2 papain-like protease were performed using Schrödinger. Stability of complexes followed the order 6M0J-Withanolide A > 6W9C-Withnaolide B > 5WRG-Withanolide B > 6LU7-Withanolide A. Maximum stable interaction(s) were observed between Withanolides A and B with SARS-CoV-2 and SARS-CoV spike glycoproteins, respectively. Withanolides A and B also displayed potent binding to pro-inflammatory markers viz. serum ferritin and IL-6. Thus, WS phytoconstituents have the potential to be tested further in vitro and in vivo as novel antiviral agents against COVID-19 patients having cancer as a co-morbidity.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-023-00184-y.

Stakeholders' views and opinions on existing guidelines on "How to Choose Mental Health Apps"

Background

Mental health Applications (Mhealth Apps) can change how healthcare is delivered. However, very little is known about the efficacy of Mhealth Apps. Currently, only minimum guidance is available in Assessment and Evaluation Tools (AETs). Therefore, this project aims to understand AET developers' perspectives and end users' experiences and opinions on "how to choose a Mhealth App".

Objective

The primary objectives were: (1) obtaining stakeholder's opinions and experiences of development and use of AETs for Mhealth Apps, their weaknesses and strengths, and barriers in their implementation of Mhealth Apps; (2) the experiences of App users, their analyzation and, obstacles in the use of apps; and (3) to quantify themes related to choosing a Mhealth App.

Methods

This qualitative study, used a sampling method to recruit six stakeholders (one App developer, two AET developers, an individual with lived experience of mental health illness, and two physicians) who were interviewed using a topic guide. These were examined by researchers (CT, WK, & FN) using thematic content analysis. Additionally, an anonymous online survey of 107 individuals was conducted.

Findings

Our analyses revealed six main themes: (a) needs and opportunities; (b) views on Mhealth apps; (c) views & opinions on AETs; (d) implementation barriers; (e) system of evaluation and; (f) future directions. The first key concept was, all stakeholders agreed that Apps could significantly impact mental health and that end-users were unaware of mental health AETs and Apps. Secondly, due to commercial interests, end-users reliability of App evaluations requires clear conflict-free guidelines. Thirdly, AETs should be evaluated and developed through a rigorous methodology. Finally, stakeholders shared insights into future developments for AETs and Mhealth Apps. Additionally, online survey respondents chose a "health professional" as their preferred source of guidance in selecting a Mhealth app (84%) and best suited to develop guidelines (70%).

Conclusion

The interviews and survey highlight the need for Mhealth Apps to be regulated and the importance of health professionals' engagement in the implementation process. Similarly, without well-defined roles for App evaluations within the health care system, it is unlikely that AETs will have wider spread use and impact without risk.

Critical barriers to sustainable capacity strengthening in global health: a systems perspective on development assistance

Background: Development assistance for health (DAH) is an important mechanism for funding and technical support to low-income countries. Despite increased DAH spending, intractable health challenges remain. Recent decades have seen numerous efforts to reform DAH models, yet pernicious challenges persist amidst structural complexities and a growing number of actors. Systems-based approaches are promising for understanding these types of complex adaptive systems. This paper presents a systems-based understanding of DAH, including barriers to achieving sustainable and effective country-driven models for technical assistance and capacity strengthening to achieve better outcomes Methods: We applied an innovative systems-based approach to explore and map how donor structures, processes, and norms pose challenges to improving development assistance models. The system mapping was carried out through an iterative co-creation process including a series of discussions and workshops with diverse stakeholders across 13 countries. Results: Nine systemic challenges emerged: 1) reliance on external implementing partners undermines national capacity; 2) prioritizing global initiatives undercuts local programming; 3) inadequate contextualization hampers program sustainability; 4) decision-maker blind spots inhibit capacity to address inequities; 5) power asymmetries undermine local decision making; 6) donor funding structures pose limitations downstream; 7) program fragmentation impedes long-term country planning; 8) reliance on incomplete data perpetuates inequities; and 9) overemphasis on donor-prioritized data perpetuates fragmentation. Conclusions: These interconnected challenges illustrate interdependencies and feedback loops manifesting throughout the system. A particular driving force across these system barriers is the influence of power asymmetries between actors. The articulation of these challenges can help stakeholders overcome biases about the efficacy of the system and their role in perpetuating the issues. These findings indicate that change is needed not only in how we design and implement global health programs, but in how system actors interact. This requires co-creating solutions that shift the structures, norms, and mindsets governing DAH models.

Prophylactic and therapeutic potential of selected immunomodulatory agents from Ayurveda against coronaviruses amidst the current formidable scenario: an in silico analysis

There is currently a dearth of specific therapies to treat respiratory infections caused by the three related species of coronaviruses viz. SARS-CoV-2, SARS-CoV and MERS-CoV. Prevention from disease is currently the safest and most convenient alternative available. The present study aimed to evaluate the preventive and therapeutic effect of fifteen phytoconstituents from medicinal plants of Ayurveda against coronaviruses by in silico screening. All the phytoconstituents exhibited rapid GI absorption and bioavailability and most of them had no toxicity versus reference drug chloroquine. BAS analyses revealed that most of the phytocomponents had favorable bioactivity scores towards biological target proteins. Principal component analysis revealed that most of the phytoconstituents fell close to chloroquine in 3D projection of chemical space. Affinity of phytoconstituents towards SARS-CoV-2 spike protein-human ACE2 complex decreased as isomeldenin > tinosporaside > EGCG whereas in case of unbound ACE2, the strength of binding followed the order isomeldenin > tinosporaside > ellagic acid. Towards SARS-CoV-2 main and papain-like proteases, the affinity decreased as isomeldenin > EGCG > tinosporaside and EGCG > tinosporaside > isomeldenin, respectively. Most phytoconstituents displayed significant binding kinetics to the selected protein targets than chloroquine. SAR analysis revealed that isomeldenin, tinosporaside, EGCG and ellagic acid bind to viral spike glycoproteins via H-bond, Pi-Pi, Pi-sigma and Pi-alkyl type interactions. Molecular dynamics simulation of isomeldenin and EGCG with SARS-CoV and SARS-CoV-2 spike glycoproteins exhibited low deviations throughout the 100 ns simulation indicating good stability and compactness of the protein-ligand complexes. Thus, the above four phytoconstituents have the potential to emerge as prophylactic and therapeutic agents against coronaviruses if investigated further in vitro and in vivo.

Critical barriers to sustainable capacity strengthening in global health: a systems perspective on development assistance

Background: Development assistance for health (DAH) is an important mechanism for funding and technical support to low-income countries. Despite increased DAH spending, intractable health challenges remain. Recent decades have seen numerous efforts to reform DAH models, yet pernicious challenges persist amidst structural complexities and a growing number of actors. Systems-based approaches are promising for understanding these types of complex adaptive systems. This paper presents a systems-based understanding of DAH, including barriers to achieving sustainable and effective country-driven models for technical assistance and capacity strengthening to achieve better outcomes Methods: We applied an innovative systems-based approach to explore and map how donor structures, processes, and norms pose challenges to improving development assistance models. The system mapping was carried out through an iterative co-creation process including a series of discussions and workshops with diverse stakeholders across 13 countries. Results: Nine systemic challenges emerged: 1) reliance on external implementing partners undermines national capacity; 2) prioritizing global initiatives undercuts local programming; 3) inadequate contextualization hampers program sustainability; 4) decision-maker blind spots inhibit capacity to address inequities; 5) power asymmetries undermine local decision making; 6) donor funding structures pose limitations downstream; 7) program fragmentation impedes long-term country planning; 8) reliance on incomplete data perpetuates inequities; and 9) overemphasis on donor-prioritized data perpetuates fragmentation. Conclusions: These interconnected challenges illustrate interdependencies and feedback loops manifesting throughout the system. A particular driving force across these system barriers is the influence of power asymmetries between actors. The articulation of these challenges can help stakeholders overcome biases about the efficacy of the system and their role in perpetuating the issues. These findings indicate that change is needed not only in how we design and implement global health programs, but in how system actors interact. This requires co-creating solutions that shift the structures, norms, and mindsets governing DAH models.

Structural interactions of phytoconstituent(s) from cinnamon, bay leaf, oregano, and parsley with SARS-CoV-2 nucleocapsid protein: A comparative assessment for development of potential antiviral nutraceuticals

SARS‐CoV‐2 has been responsible for causing 6,218,308 deaths globally till date and has garnered worldwide attention. The lack of effective preventive and therapeutic drugs against SARS‐CoV‐2 has further worsened the scenario and has bolstered research in the area. The N‐terminal and C‐terminal RNA binding domains (NTD and CTD) of SARS‐CoV‐2 nucleocapsid protein represent attractive therapeutic drug targets. Naturally occurring compounds are an excellent source of novel drug candidates due to their structural diversity and safety. Ten major bioactive compounds were identified in ethanolic extract (s) of Cinnamomum zeylanicum, Cinnamomum tamala, Origanum vulgare, and Petroselinum crispum using HPLC and their cytotoxic potential was determined against cancer and normal cell lines by MTT assay to ascertain their biological activity in vitro. To evaluate their antiviral potential, the binding efficacy to NTD and CTD of SARS‐CoV‐2 nucleocapsid protein was determined using in silico biology tools. In silico assessment of the phytocomponents revealed that most of the phytoconstituents displayed a druglike character with no predicted toxicity. Binding affinities were in the order apigenin > catechin > apiin toward SARS‐CoV‐2 nucleocapsid NTD. Toward nucleocapsid CTD, the affinity decreased as apigenin > cinnamic acid > catechin. Remdesivir displayed lesser affinity with NTD and CTD of SARS‐CoV‐2 nucleocapsid proteins than any of the studied phytoconstituents. Molecular dynamics (MD) simulation results revealed that throughout the 100 ns simulation, SARS‐CoV‐2 nucleocapsid protein NTD‐apigenin complex displayed greater stability than SARS‐CoV‐2 nucleocapsid protein NTD‐cinnamic acid complex. Hence, apigenin, catechin, apiin and cinnamic acid might prove as effective prophylactic and therapeutic candidates against SARS‐CoV‐2, if examined further in vitro and in vivo.

Anticancer potential of Phoenix dactylifera L. seed extract in human cancer cells and pro-apoptotic effects mediated through caspase-3 dependent pathway in human breast cancer MDA-MB-231 cells: an in vitro and in silico investigation

Background

Phoenix dactylifera L. has a diverse set of pharmacological properties due to its distinct phytochemical profile. The purpose of this study was to investigate the anticancer potential of Phoenix dactylifera seed extract (PDSE) in human breast cancer MDA-MB-231 and MCF-7 cells, as well as liver cancer HepG2 cells, and to investigate the anticancer efficacy in triple-negative MDA-MB-231 cells, followed by in silico validation of the molecular interaction between active components of PDSE and caspase-3, an apoptosis executioner protein .

Methods

In this study, human cancer cell lines were cultured and subsequently treated with 10 to 100 μg/mL of PDSE. MTT test was performed to determine the cell viability, MMP was measured using fluorescent probe JC-1, nuclear condensation was determined by Hoechst 33258 dye, Annexin V-FITC & PI staining and cell cycle analysis were evaluated through flow cytometer, and apoptotic markers were detected using western blotting. The bioactive agents in PDSE were identified using high-performance liquid chromatography (HPLC) analysis. The binding affinity was validated using molecular docking tools AutoDock Vina and iGEMDOCK v2.1.

Results

Cell viability data indicated that PDSE inhibited cell proliferation in both breast cancer cells and liver cancer cells. MDA-MB-231 cells showed maximum growth inhibition with an IC₅₀ value of 85.86 μg/mL for PDSE. However, PDSE did not show any significant toxicity against the normal Vero cell line. PDSE induced MMP loss and formation of apoptotic bodies, enhanced late apoptosis at high doses and arrested cells in the S phase of cell cycle. PDSE activated the enzymatic activity of cleaved caspase-3 and caused the cleavage of poly-ADB ribose polymerase (PARP) protein. PDSE upregulated pro-apoptotic Bax protein markedly but  no significant effect on tumor suppressor protein p53, while it downregulated the anti-apoptotic Bcl-2 protein expression. HPLC analysis showed the presence of rutin and quercetin bioactive flavonols in ethanolic extract of PDS. Interestingly, both active components revealed a strong binding interaction with amino acid residues of caspase-3 (PDB ID: 2XYP; Hetero 4-mer - A2B2) protein.

Conclusion

PDS could serve as a potential medicinal source for apoptotic cell death in human breast cancer cells and, thus, could be used as a promising and crucial candidate in anticancer drug development. This study warrants further in vivo research, followed by clinical investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03533-0.

Data revolution, health status transformation and the role of artificial intelligence for health and pandemic preparedness in the African context

Background

Artificial Intelligence (AI) platforms, increasingly deployed in public health, utilize robust data systems as a critical component for health emergency preparedness. Yet, Africa faces numerous challenges in the availability, analyses, and use of data to inform health decision-making. Countries have limited access to their population data. Those with access, struggle to utilize these data for program improvements. Owing to the rapid growth of mobile phone ownership and use in the region, Africa is poised to leverage AI technologies to increase the adoption, access and use of data for health. To discuss and propose solutions for responsible development and adoption of innovations like AI in Africa, a virtual workshop was organized from the 21st to 24th June, 2021. This report highlights critical policy dimensions of strengthening digital health ecosystems by high-level policymakers, technical experts, academia, public and private sector partners.

Method

The four days’ workshop focused on nine sessions, with each session focusing on three themes. Discussions during the sessions concentrated on public and private sectors, the academia and multilateral organizations’ deployment of AI. These discussions expanded participants’ understanding of AI, the opportunities and challenges that exist during adoption, including the future of AI for health in the African region. Approximately 250 participants attended the workshop, including countries representatives from ministries of Health, Information and Technology, Developmental Organizations, Private Sector, Academia and Research Institutions among others.

Results

The workshop resolved that governments and relevant stakeholders should collaborate to ensure that AI and digital health receive critical attention. Government ownership and leadership were identified as critical for sustainable financing and effective scale-up of AI-enabled applications in Africa. Thus, government is to ensure that key recommendations from the workshop are implemented to improve health sector development in Africa.

Conclusions

The AI workshop was a good forum to deliberate important issues regarding AI for health in the African context. It was concluded that there is a need to focus on vital priorities in deploying AI in Africa: Data protection, privacy and sharing protocols; training and creating platforms for researchers; funding and business models; developing frameworks for assessing and implementing AI; organizing forums and conferences on AI; and instituting regulations, governance and ethical guidelines for AI. There is a need to adopt a health systems approach in planning for AI to reduce inefficiencies, redundancies while increasing effectiveness in the use of AI. Thus, robust collaborations and partnerships among governments and various stakeholders were identified as key.

Higher illness burden is associated with reduced heart rate variability in bipolar disorder

Introduction

Bipolar disorder (BD) is associated with premature death and ischemic heart disease is the main cause of excess mortality. The predictive power of heart rate variability (HRV) for mortality has been confirmed in patients with or without cardiovascular disease. While several studies have analyzed the association between HRV and BD, their results are incongruent; and none has analyzed the effect of the clinical factors characterizing illness burden on HRV.

Objectives

To assess the association between HRV and the following factors characterizing illness burden: illness duration, number and type of previous episode(s), duration of the most severe depressive or hypomanic/manic episode, severity of episodes, co-morbid psychiatric disorders, family history of BD or suicide, and duration and polarity of current episode in participants experiencing one.

Methods

We used a wearable device in 53 BD participants to assess the association between HRV using 4 measures (RMSSD, SDANN, SDNN and RR Triangular Index) and the abovementioned clinical factors characterizing illness burden. For each of the 4 HRV measures we ran 11 models, one for each burden of illness clinical factor as an independent variable.

Results

Longer illness duration, higher number of depressive episodes, and family history of suicide were negatively correlated with HRV; in the 14 participants experiencing a depressive episode, the MADRS score was negatively correlated with HRV

Conclusions

Our study analyzed the association between burden of illness and HRV in BD, while controlling for functional cardiovascular status, age, sex, BMI, education, and treatment. Our results showed that high illness burden is associated with reduced HRV.

Disclosure

No significant relationships.

Virtual screening of phytoconstituents from miracle herb nigella sativa targeting nucleocapsid protein and papain-like protease of SARS-CoV-2 for COVID-19 treatment

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel etiological agent of coronavirus disease 2019 (COVID-19). Nigella sativa, commonly known as black seed or black cumin, has been a historical and traditional plant since thousands of years. Based on their therapeutic efficacy, the chief components of terpenoids and flavonoids were selected from N. sativa seeds and seed oil. This study was designed to check the antiviral efficacy of N. sativa main phytoconstituents against five potential targets of SARS-CoV-2 using in silico structure-based virtual screening approach. Out of twenty five phytocomponents, ten components showed best binding affinity against two viral proteins viz. N-terminal RNA binding domain (NRBD; PDB ID: 6M3M) of nucleocapsid protein and papain-like protease (PL-_PRO; PDB ID: 6W9C) of SARS-CoV-2 using AutoDock 4.2.6, AutoDock Vina and iGEMDOCK. PASS analyses of all ten phytocomponents using Lipinski's Rule of five showed promising results. Further, druglikeness and toxicity assessment using OSIRIS Data Warrior v5.2.1 software exhibited the feasibility of phytocomponents as drug candidates with no predicted toxicity. Molecular dynamics simulation study of NRBD of SARS-CoV-2 nucleocapsid protein-alpha-spinasterol complex and PL-_PRO-cycloeucalenol complex displayed strong stability at 300 K. Both these complexes exhibited constant root mean square deviation (RMSDs) of protein side chains and Cα atoms throughout the simulation run time. Interestingly, PL-_PRO and NRBD are key proteins in viral replication, host cell immune evasion and viral assembly. Thus, NRBD and PL-_PRO have the potential to serve as therapeutic targets for N. sativa phytoconstituents in drug discovery process against COVID-19.

The Significance of ERG and Androgen Receptor Expression in Adenocarcinoma Prostate

Background Fusions of transmembrane protease, serine 2 (TMPRSS2) with erythroblast transformation specific transcription factors have been found in prostate cancer. The v-etserythroblastosis virus E26 oncogene homologue (ERG) is a proto-oncogene of the erythroblast transformation specific transcription factor family. TMPRSS2-ERG fusion is the most common molecular alteration present in about 50% of prostatic adenocarcinomas. Androgen receptor (AR) plays a key role in prostate development and is involved in the progression of prostate cancer. Objective To evaluate the significance of combined ERG and AR expression in cases of prostatic adenocarcinoma. Method The study was conducted at Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India. Formalin fixed-paraffin embedded archival prostatic tissue specimens were obtained. A total of 10 cases of prostatic adenocarcinoma were included in the study. Immunohistochemistry for Androgen receptor was done by the standard protocol. Multiplex immunohistochemical staining was done for ERG+CK5 using a primary antibody cocktail of mouse and rabbit antibodies. Result Specific AR immunostaining was exclusively nuclear and was present in all 10 cases in varying intensity. Specific ERG immunostaining was nuclear and was present in seven cases (70%) and absent in three cases (30%). The three cases that were negative for ERG had a Gleason score of ≤ 6 and the AR staining was strong and present in about 90% of the cells. Gleason score was directly related to the ERG staining while AR staining was inversely related to the ERG staining. Conclusion The prognostic value of combined ERG and AR over-expression, its associated genes should be further investigated as potential therapeutic targets in prostate cancer progression. Preliminary data is being presented. Larger prospective studies with survival analysis are essential for prognostic significance.

Phytochemical characterization and biological activity evaluation of ethanolic extract of Cinnamomum zeylanicum

ETHNOPHARMACOLOGICAL RELEVANCE

India being a multicultural nation, every region of the country offers a distinct culinary flavor and taste. These flavors are attributed to spices and condiments which form the mainstay of Indian cuisine. Most of these spices and condiments are derived from various biodiversity hotspots in India and form the crux of India's multidiverse and multicultural cuisine. Apart from their varying aromas, flavors and tastes, these spices and condiments are known to possess several medicinal properties also. Most of these spices find considerable mention in Ayurveda, the indigenous system of medicine, as panaceas for several aliments. Cinnamomum zeylanicum (CZ), belonging to family Lauraceae and commonly known as cinnamon is one such spice known to have diverse medicinal properties since time immemorial.

AIM OF THE STUDY

In the present study, apoptotic and anti-microbial activity of ethanolic extract of CZ was evaluated against human breast cancer cell line MDA-MB-231 and compared for its effect on normal kidney epithelial cell line Vero.

MATERIALS AND METHODS

Ethanolic extract of tree bark of CZ was used to determine the cytotoxic effect on MDA-MB-231 using Trypan blue dye exclusion method and cytometry. The tested dose of the extract was 10-100 µg/mL. Antibacterial activity was determined using disc diffusion method against Staphylococcus aureus and Escherichia coli in the range 2-10 mg/mL. Apoptotic activity was determined using DNA fragmentation assay.

RESULTS

Ethanolic extract of CZ was found to have an IC₅₀ value of 25 µg/mL against MDA cell line. On the other hand, CZ extract did not have any significant effect on Vero cells even at 100 µg/mL (IC₅₀ > 100 µg/mL). The ethanolic extract of CZ bark showed significant antibacterial activity against S. aureus at 10 mg/mL while no appreciable activity was detected against E. coli. DNA isolated from extract treated cancer cells showed a fragmentation pattern characteristic of apoptosis. However, no DNA fragmentation was observed in DNA isolated from extract treated Vero cells.

CONCLUSION

Ethanolic bark extract of CZ could be potentially beneficial in treating breast cancer and may be of interest for future studies in developing integrative cancer therapy against proliferation, metastasis, and migration of breast cancer cells.

Rosuvastatin ameliorates cognitive impairment in rats fed with high-salt and cholesterol diet via inhibiting acetylcholinesterase activity and amyloid beta peptide aggregation

Amyloid beta (Aβ) peptide aggregation and cholinergic neurodegeneration are involved in the development of cognitive impairment. Therefore, in this article, we examined rosuvastatin (RSV), an oral hypolipidemic drug, to determine its potential as a dual inhibitor of acetylcholinesterase (AChE) and Aβ peptide aggregation for the treatment of cognitive impairment. Molecular docking study was done to examine the affinity of RSV with Aβ_1-42 and AChE in silico. We also employed neurobehavioral activity tests, biochemical estimation, and histopathology to study the anti-Aβ_1-42 aggregation capability of RSV in vivo. Molecular docking study provided evidence that RSV has the best binding conformer at its receptor site or active site of an enzyme. The cognitive impairment in female Wistar rats was induced by high-salt and cholesterol diet (HSCD) ad libitum for 8 weeks. RSV ameliorated serum cholesterol level, AChE activity, and Aβ_1-42 peptide aggregations in HSCD induced cognitive impairment. In addition, RSV-treated rats showed greater scores in the open field (locomotor activity) test. Moreover, the histopathological studies in the hippocampus and cortex of rat brain also supported that RSV markedly reduced the cognitive impairment and preserved the normal histoarchitectural pattern of the hippocampus and cortex. Taken together, these data indicate that RSV may act as a dual inhibitor of AChE and Aβ_1-42 peptide aggregation, therefore suggesting a therapeutic strategy for cognitive impairment treatment.

Antidyslipidemic Effect of Ocimum sanctum Leaf Extract in Streptozotocin Induced Diabetic Rats

The antidyslipidemic activity of Ocimum sanctum leaf extract was studied in streptozotocin induced diabetic rats. In this model, there was significant increase in plasma markers of diabetic-dyslipidemia following diminution of lipid metabolizing enzymes. Oral administration of leaf extract (500 mg/kg b.w.p.o.) for 15 days resulted in significant decrease in diabetogenic and dyslipidemia parameters; namely blood glucose, glycosylated hemoglobin, lipid peroxide, free fatty acids, small dense low density lipoprotein, lipid and protein components of plasma lipoproteins, adipose and liver. The regulation of lipids was accompanied by stimulation of postheparin lipolytic activity, reactivation of lecithin cholesterol acyl transferase and hepatic lipoprotein lipase enzymes. The results of the present study demonstrated antidyslipidemic and antioxidant activities in leaf extract of O. sanctum which could be used in prevention of diabetic-dyslipidemia and related complications.

Assessment of fluoride level in groundwater and prevalence of dental fluorosis in Didwana block of Nagaur district, Central Rajasthan, India

BACKGROUND

In India, for the high concentration of fluoride in groundwater, people are at risk of dental fluorosis. The problem is common in various states of India. The condition in Rajasthan is worse where all districts have such a problem.

OBJECTIVE

To study the fluoride concentration in groundwater and prevalence of dental fluorosis in Didwana block of Nagaur district, Central Rajasthan, India.

METHODS

The fluoride concentration in water of 54 villages was measured electrochemically, using fluoride ion selective electrode. Dental fluorosis was assessed in 1136 people residing in study area by Dean's classification for dental fluorosis.

RESULTS

The fluoride concentration in groundwater in studied sites ranged from 0.5 to 8.5 mg/L. The concentration of fluoride was more than the maximum permissible limit set by WHO and Bureau of Indian Standards (1 mg/L) in 48 groundwater sources. Of 1136 people studied, 788 (69.4%; 95% CI: 66.7%-72.1%) had dental fluoros---252 had mild and 74 had severe dental fluorosis.

CONCLUSION

High level of fluoride in drinking water of Didwana block of Nagaur district, Central Rajasthan, India, causes dental fluorosis in most people in the region and is an important health problem that needs prompt attention.

Autoresistance to ErbB2 kinase inhibitors: Elucidating mechanisms and identfying strategies to prevent its onset in breast cancer

2075

Background: Clinical efficacy of ErbB1/ErbB2 kinase inhibitors is limited by the development of acquired autoresistance. Developing clinically relevant models to study the mechanism(s) of acquired autoresistance will identify therapeutic strategies to prevent its onset. Methods: BT474 cells, an ErbB2-overexpressing/ER+ breast cancer line sensitive to lapatinib-induced apoptosis were chronically exposed to lapatinib, simulating chronic administration of lapatinib in the clinic. Lapatinib-resistant cells (rBT474) and single cell clones were established. Baseline gene expression in parental BT474 and rBT474 cells was compared using Human Affymetrix oligonucleotide arrays. Sequential tumor biopsies were analyzed by quantitative IHC as part of a clinical trial using lapatinib monotherapy (1500mg/d) in patients with metastatic breast cancer. Results: Gene expression and protein analysis indicates that acquired resistance to lapatinib is mediated by increased estrogen receptor (ER) signaling rather than loss of ErbB2 expression or insensitivity of the ErbB2-MAPK-PI3K pathways to lapatinib. Activation of ER signaling results from de-repression of FOXO3a and transient up-regulation of caveolin-1, both facilitating ER transcriptional activity. Gene interference studies confirm that acquired resistance involves a switch in survival dependence and regulation of survivin from ErbB2 to ER. Since ErbB2 signaling is operative in rBT474 cells, treating parental BT474 cells with lapatinib plus (i) fulvestrant, or (ii) estrogen deprivation prevents the onset of acquired lapatinib resistance compared with either therapy alone. Importantly, increased ER signaling occurs in patients with ErbB2-overexpressing/ER+ breast cancers treated with lapatinib monotherapy, consistent with changes in cell lines. Conclusions: Chronic lapatinib monotherapy induces a shift in the dependence of cell survival from ErbB2 to ER. Combining lapatinib with selected anti-estrogens prevents its onset in cell lines and warrants clinical validation. Establishing models of acquired resistance simulating the clinic provides a tool to identify strategies to improve treatment options for patients with ErbB2-overexpressing breast cancers.

[Table: see text]

Diabetes mellitus and bladder cancer--an epidemiological relationship?

An epidemiological association between diabetes mellitus and transitional cell carcinoma of the bladder has been proposed. This study looked retrospectively at 125 patients with transitional cell carcinoma of the bladder as a study group and 80 other hospital patients with conditions not specifically associated with diabetes mellitus as a control group. Diabetic patients had an increased, significant odds ratio for bladder cancer compared with non diabetics even after adjustment for smoking and age [OR: 2.69 p=0.049 (95% CI 1.006-7.194)] A history of smoking OR 2.16 p=0.013 (95% C.I. 1.175-3.964) is a significant independent association with transitional cell carcinoma of the bladder as is age: p=0.001 OR 1.07. We propose potential pathogenic pathways for transitional cell carcinoma of the bladder in diabetic patients based on altered integrin and cadherin distribution in urothelial cells in diabetic patients. A larger study is planned to confirm an association between diabetes mellitus and transitional cell carcinoma of the bladder.

Plk3 functionally links DNA damage to cell cycle arrest and apoptosis at least in part via the p53 pathway

Polo-like kinase 3 (Plk3, previously termed Prk) contributes to regulation of M phase of the cell cycle (Ouyang, B., Pan, H., Lu, L., Li, J., Stambrook, P., Li, B., and Dai, W. (1997) J. Biol. Chem. 272, 28646-28651). Plk3 physically interacts with Cdc25C and phosphorylates this protein phosphatase predominantly on serine 216 (Ouyang, B., Li, W., Pan, H., Meadows, J., Hoffmann, I., and Dai, W. (1999) Oncogene 18, 6029-6036), suggesting that the role of Plk3 in mitosis is mediated, at least in part, through direct regulation of Cdc25C. Here we show that ectopic expression of a kinase-active Plk3 (Plk3-A) induced apoptosis. In response to DNA damage, the kinase activity of Plk3 was rapidly increased in an ATM-dependent manner, whereas that of Plk1 was markedly inhibited. Recombinant Plk3 phosphorylated in vitro a glutathione S-transferase fusion protein containing p53, but not glutathione S-transferase alone. Recombinant Plk1 also phosphorylated p53 but on residues that differed from those targeted by Plk3. Co-immunoprecipitation and pull-down assays demonstrated that Plk3 physically interacted with p53 and that this interaction was enhanced upon DNA damage. In vitro kinase assays followed by immunoblotting showed that serine 20 of p53 was a target of Plk3. Furthermore, expression of a kinase-defective Plk3 mutant (Plk3(K52R)) resulted in significant reduction of p53 phosphorylation on serine 20, which was correlated with a decrease in the expression of p21 and with a concomitant increase in cell proliferation. These results strongly suggest that Plk3 functionally links DNA damage to cell cycle arrest and apoptosis via the p53 pathway.

DNA polymerase beta expression differences in selected human tumors and cell lines

A long-standing question in cancer biology has been the extent to which DNA repair may be altered during the process of carcinogenesis. We have shown recently that DNA polymerase beta (beta-pol) provides a rate-determining function during in vitro repair of abasic sites by one of the mammalian DNA base excision repair pathways. Therefore, altered expression of beta-pol during carcinogenesis could alter base excision repair and, consequently, be critical to the integrity of the mammalian genome. We examined the expression of beta-pol in several cell lines and human adenocarcinomas using a quantitative immunoblotting method. In cell lines from normal breast or colon, the level of beta-pol was approximately 1 ng/mg cell extract, whereas in all of the breast and colon adenocarcinoma cell lines tested, a higher level of beta-pol was observed. In tissue samples, colon adenocarcinomas had a higher level of beta-pol than adjacent normal mucosa. Breast adenocarcinomas exhibited a wide range of beta-pol expression: one tumor had a much higher level of beta-pol (286 ng/mg cell extract) than adjacent normal breast tissue, whereas another tumor had the same level of beta-pol as adjacent normal tissue. Differences in beta-pol expression level, from normal to elevated, were also observed with prostate adenocarcinomas. All kidney adenocarcinomas tested had a slightly lower beta-pol level than adjacent normal tissue. This study reveals that the base excision repair enzyme DNA polymerase beta is up-regulated in some types of adenocarcinomas and cell lines, but not in others.

Extracorporeal shock wave lithotripsy for the rescue of post-endoscopic or surgically retained biliary duct stones: does saline irrigation affect the outcome?

Extracorporeal shock wave lithotripsy (ESWL) has been found valuable in situations where obstructing stones in the common bile or intrahepatic ducts are retained following surgery or attempted endoscopic removal. However, success rates are dependent on the type of ESWL system employed and upon a high frequency rate of repeated treatment sessions. We outline our experience with 23 cases of retained, obstructing bile duct stones, ranging in size from 10 to 40 mm diameter, treated with Dornier HM3 ESWL. In the initial 12 patients in the series, successful stone fragmentation occurred in 83% of cases with a median 1.6 treatment sessions. In the latter 11 cases in the series, patients were treated prone and the stone-bearing biliary duct was irrigated with saline solution during ESWL delivery. With this technique, successful stone break up was achieved in all patients (100%) with a single treatment session. Endoscopic sphincterotomy is, however, a prerequisite for extracorporeal lithotripsy and, despite the high success rates now available with new techniques, we believe the ESWL should continue to be employed in support of primary endoscopic methods of management for obstructing bile duct stones.

An epidemiologic study of cystitis among Muslim women attending an out-patients clinic in Karachi

Cystitis is considered to be one of the most common infections afflicting women of all age groups. It has been suggested that personal hygiene customs may influence the prevalence of cystitis. In this study, 130 women of child bearing age attending the out-patients clinic were interviewed in order to determine the frequency of cystitis and its associated risk factors including personal hygiene practices. Twenty seven percent of the women reported suffering from cystitis atleast once in the past, comparable to reported studies from the United States but higher than reported from other Muslim countries. Sixty-three percent of women reported their first episode during pregnancy and a significant relationship was observed between parity and cystitis (p value < 0.000). However, personal hygiene practices following micturition or sexual intercourse bore no significant association with cystitis. Cystitis, commonly reported among Pakistani married women, occurs primarily during pregnancy. Preventive measures during pregnancy are suggested.

Mammalian DNA ligase III: molecular cloning, chromosomal localization, and expression in spermatocytes undergoing meiotic recombination

Three biochemically distinct DNA ligase activities have been identified in mammalian cell extracts. We have recently purified DNA ligase II and DNA ligase III to near homogeneity from bovine liver and testis tissue, respectively. Amino acid sequencing studies indicated that these enzymes are encoded by the same gene. In the present study, human and murine cDNA clones encoding DNA ligase III were isolated with probes based on the peptide sequences. The human DNA ligase III cDNA encodes a polypeptide of 862 amino acids, whose sequence is more closely related to those of the DNA ligases encoded by poxviruses than to replicative DNA ligases, such as human DNA ligase I. In vitro transcription and translation of the cDNA produced a catalytically active DNA ligase similar in size and substrate specificity to the purified bovine enzyme. The DNA ligase III gene was localized to human chromosome 17, which eliminated this gene as a candidate for the cancer-prone disease Bloom syndrome that is associated with DNA joining abnormalities. DNA ligase III is ubiquitously expressed at low levels, except in the testes, in which the steady-state levels of DNA ligase III mRNA are at least 10-fold higher than those detected in other tissues and cells. Since DNA ligase I mRNA is also present at high levels in the testes, we examined the expression of the DNA ligase genes during spermatogenesis. DNA ligase I mRNA expression correlated with the contribution of proliferating spermatogonia cells to the testes, in agreement with the previously defined role of this enzyme in DNA replication. In contrast, elevated levels of DNA ligase III mRNA were observed in primary spermatocytes undergoing recombination prior to the first meiotic division. Therefore, we suggest that DNA ligase III seals DNA strand breaks that arise during the process of meiotic recombination in germ cells and as a consequence of DNA damage in somatic cells.

The aetiological and clinical pattern of childhood urolithiasis in Saudi Arabia

The clinical and aetiological pattern in 85 stone-forming children presenting to an integrated nephrourological service in Riyadh is reviewed. All patients were below the age of 15 years, the male to female ratio being 2:1. Only 2 children presented with bladder calculi. The remaining all had upper tract stones and, in 12 cases, these were bilateral. Of 34 calculi recovered for analysis, one-third was predominantly calcium oxalate and a further third was composed of uric acid or urate. Four patients had cysteine stones and the remaining 7 presented mixed calcium stones, 6 (17.6%) being struvite and infection-related. Of the 85 patients 55 were treated successfully with extracorporeal shock wave lithotripsy, 16 underwent surgery and 7 had their stones removed by endourological procedures. In the remaining 7 children, stones dissolved or were passed spontaneously during medical therapy. Nine children (10.6%) showed a primary metabolic defect leading to their stone formation, 10 (11.8%) had a predisposing anatomical anomaly and 15 (17.6%) presented with urinary tract infection. Of the remaining 51 patients (60%) with idiopathic disease, 6 showed hypercalciuria on investigation and 2 children may have formed their stones due to prolonged recumbency.

Specific inhibition of DNA polymerase beta by its 14 kDa domain: role of single- and double-stranded DNA binding and 5'-phosphate recognition

DNA polymerase beta (beta-polymerase) has been implicated in short-patch DNA synthesis in the DNA repair pathway known as base excision repair. The native 39 kDa enzyme is organized into four structurally and functionally distinct domains. In an effort to examine this enzyme as a potential therapeutic target, we analyzed the effect of various beta-polymerase domains on the activity of the enzyme in vitro. We show that the 14 kDa N-terminal segment of beta-polymerase, which binds to both single- and double-stranded DNA, but lacks DNA polymerase activity, inhibits beta-polymerase activity in vitro. Most importantly, the 8, 27 and 31 kDa domains of beta-polymerase do not inhibit beta-polymerase activity, demonstrating that the inhibition by the 14 kDa domain is specific. The inhibition of beta-polymerase activity in vitro is abolished by increasing the concentrations of both of the substrates (template-primer and deoxynucleoside triphosphate). In contrast, an in vitro base excision repair assay is inhibited in a domain specific manner by the 14 kDa domain even in the presence of saturating substrates. The inhibition of beta-polymerase activity by the 14 kDa domain appears specific to beta-polymerase as this domain does not inhibit either mammalian DNA polymerase alpha or Escherichia coli polymerase I (Klenow fragment). These data suggest that the 14 kDa domain could be used as a potential inhibitor of intracellular beta-polymerase and that it may provide a means for sensitizing cells to therapeutically relevant DNA damaging agents.

Purification and characterization of DNA ligase III from bovine testes. Homology with DNA ligase II and vaccinia DNA ligase

Mammalian cell nuclei contain three biochemically distinct DNA ligases. In the present study we have found high levels of DNA ligase I and DNA ligase III activity in bovine testes and have purified DNA ligase III to near homogeneity. The high level of DNA ligase III suggests a role for this enzyme in meiotic recombination. In assays measuring the fidelity of DNA joining, we detected no significant differences between DNA ligases II and III, whereas DNA ligase I was clearly a more faithful enzyme and was particularly sensitive to 3' mismatches. Amino acid sequences of peptides derived from DNA ligase III demonstrated that this enzyme, like DNA ligase II, is highly homologous with vaccinia DNA ligase. The absence of unambiguous differences between homologous peptides from DNA ligases II and III (10 pairs of peptides, 136 identical amino acids) indicates that these enzymes are either derived from a common precursor polypeptide or are encoded from the same gene by alternative splicing. Based on similarities in amino acid sequence and biochemical properties, we suggest that DNA ligases II and III, Drosophila DNA ligase II, and the DNA ligases encoded by the pox viruses constitute a distinct family of DNA ligases that perform specific roles in DNA repair and genetic recombination.

Mammalian DNA ligase II is highly homologous with vaccinia DNA ligase. Identification of the DNA ligase II active site for enzyme-adenylate formation

Mammalian cells contain three biochemically distinct DNA ligases. In this report we describe the purification of DNA ligase II to homogeneity from bovine liver nuclei. This enzyme interacts with ATP to form an enzyme-AMP complex, in which the AMP moiety is covalently linked to a lysine residue. An adenylylated peptide from DNA ligase II contains the sequence, Lys-Tyr-Asp-Gly-Glu-Arg, which is homologous to the active site motif conserved in ATP-dependent DNA ligases. The sequences adjacent to this motif in DNA ligase II are different from the comparable sequences in DNA ligase I, demonstrating that these enzymes are encoded by separate genes. The amino acid sequences of 15 DNA ligase II peptides exhibit striking homology (65% overall identity) with vaccinia DNA ligase. These peptides are also homologous (31% overall identity) with the catalytic domain of mammalian DNA ligase I, indicating that the genes encoding DNA ligases I and II probably evolved from a common ancestral gene. Since vaccinia DNA ligase is not required for DNA replication but influences the ability of the virus to survive DNA damage, the homology between this enzyme and DNA ligase II suggests that DNA ligase II may be involved in DNA repair.

Multisite point-of-care potassium testing for patient-focused care

In the past two decades, a dominant paradigm has been the main laboratory, which is often located far from the patient and characterized by slow response times. The invention of whole blood biosensors and the innovation of point-of-care testing have initiated a paradigm shift in diagnostic medicine that supports the trend toward patient-focused care. The objective of this study was to compare point-of-care potassium testing performed with a handheld potassium analyzer (STAT K, PDx Technologies Inc, Westlake Village, Calif) in the cardiac and intensive care units with potassium measurements obtained similarly in the main laboratory. Two critical care nurses performed point-of-care testing for critically ill patients. In a series of 56 specimens, the mean +/- SD potassium levels were 3.91 +/- 0.53 and 3.94 +/- 0.57 mmol/L when testing was performed at the bedside and in the main laboratory, respectively. The mean paired difference, -0.03 mmol/L, between point-of-care and main laboratory results was not statistically or clinically significant. Point-of-care potassium testing is accurate and precise, as well as clinically efficient for use in patient-focused care settings.

Primary extracorporeal shockwave lithotripsy in management of large bladder calculi

Large bladder calculi are often outside the range of treatment with conventional endoscopic lithotrites because of either anatomic factors or the mechanical limits of available instruments. Alternative methods of cystolithotripsy: ultrasonic, electrohydraulic, or laser, can prove time-consuming or even hazardous, so that open surgery is often the most expeditious option. We report our experience using Dornier HM3 extracorporeal shockwave lithotripsy (SWL) for initial bladder stone reduction preparatory to transurethral litholapaxy and definitive treatment of any underlying obstructive pathology. Primary cystolitholapaxy was judged impractical in these 24 patients (21 adults and 3 children) presenting 31 large bladder stones (mean size 35.6 mm). In all patients, primary transpelvic SWL was followed immediately by endoscopic evacuation of stone debris or cystolitholapaxy. In addition, 10 of the 24 patients (42%) underwent a definitive endoscopic operation for treatment of an underlying obstructive lesion at either the same or a follow-on session. Morbidity was minimal, and the mean hospital stay after the initial SWL treatment was 3.5 days. In our experience, Dornier SWL has proved invaluable in enabling cystolitholapaxy of very large bladder calculi that would otherwise require protracted and difficult endoscopic manipulation or open surgery.

Synthesis and biological studies on some organo-tin and lead halo and mixed halo-pseudohalo anionic complexes

Some new anionic complexes of organo-tin(IV) and lead (IV) isolated in combination of tetraorgano-ammonium phosphonium and stibonium cation(s). L[R4-nMXnY] and L2[R2MX2Y2], where R = C2H5, C4H9 or C6H5; M = Sn or Pb; X = Y = Cl = Br, I, N3, NCS; n = 1, 2 and L = R4M1 (M1 = N, P, Sb), whose structures were confirmed by correct elemental analyses, molar conductance values, van't Hoff factor and IR spectral studies, were synthesized and evaluated for anti-convulsant activity in vivo and antiviral and antibacterial activity in vitro. A few of them exhibited promising activity. In addition, the toxicity (ALD50) and effects on the central nervous system of these complexes have been studied in mice.

Elevation of topoisomerase I messenger RNA, protein, and catalytic activity in human tumors: demonstration of tumor-type specificity and implications for cancer chemotherapy

Topoisomerase I has been identified as an intracellular target of camptothecin, a plant alkaloid with anticancer activity. Various lines of evidence suggest that the sensitivity of cells to this drug is directly related to the topoisomerase I content. In humans, the levels of topoisomerase I have been shown to be elevated in colorectal tumors, compared to normal colon mucosa. The aim of our study was to determine whether (a) topoisomerase I levels are elevated in other solid tumors, (b) the elevated enzyme is catalytically active in these tumors, and (c) the increase in topoisomerase I levels in colorectal tumors is a result of increased transcription or translation. Topoisomerase I levels were quantitated in crude extracts from colorectal, prostate, and kidney tumors and their matched normal counterparts by Western blotting and by direct determination of catalytic activity, and mRNA levels were determined by Northern blotting. By Western blotting, colorectal tumors showed 5-35-fold increases in topoisomerase I levels, compared to their normal colon mucosa. In the case of prostate tumors, the increase was 2-10-fold, compared with benign hyperplastic prostate tissue from the same patients. However, no difference was observed in topoisomerase I levels in kidney tumors, compared to their normal counterparts. The catalytic activity of topoisomerase I was determined by a quantitative 32P-transfer assay in crude homogenates, without isolating nuclei. Colorectal and prostate tumors exhibited 11-40- and 4-26-fold increases, respectively, in catalytic activity. However, kidney tumors did not show any alteration in catalytic activity, compared to their normal matched samples. Thus, for all three tumor types there was a good correlation between enzyme levels and catalytic activity. Finally, colorectal tumors were analyzed for steady state mRNA levels. A 2-33-fold increase in mRNA levels was found in colorectal tumors, compared to normal colon mucosa. These results suggest that alterations in topoisomerase I expression in humans are tumor type specific and that the increase in topoisomerase I levels results from either increased transcription of the topoisomerase I gene or increased mRNA stability.

Incidence of bacteremia and bacteriuria in patients with non-infection-related urinary stones undergoing extracorporeal shock wave lithotripsy

In a prospective pilot study, 26 patients with non-infection-related renal or ureteric stones and sterile urine were examined for evidence of bacteriuria and bacteremia following extracorporeal shock wave lithotripsy (SWL). Blood samples were obtained for aerobic and anaerobic bacterial culture at the end of, and 1 hour after, the SWL procedure. Urine cultures were performed 24 hours before and after treatment. Bacteremia was recorded in 7.7% of the patients immediately after SWL but in no patient at 1 hour after treatment. None of the patients manifested significant bacteriuria or post-SWL fever. These findings support the contention that, provided the urine is sterile and a negative history of urosepsis is available, antibiotic prophylaxis is unnecessary in patients with non-infected renal stones submitted to SWL treatment.

Narcolepsy

Narcolepsy afflicts more than 200,000 Americans. In most cases the first symptom of the disease, excessive daytime sleepiness, develops during childhood or adolescence. This initial presentation is followed by cataplexy or other auxiliary symptoms several years later. Not infrequently, many years pass before the proper diagnosis of narcolepsy is made. Narcolepsy is a chronic lifelong disease without periods of remission. Excessive daytime sleepiness, inappropriate sleep attacks, and the pathognomonic symptom of cataplexy, are diagnostic of narcolepsy. Confirmation of the disease is made by a multiple sleep latency test. Although still not being used for diagnostic purposes, the association between narcolepsy and the human leukocyte group A (HLA) antigen DR2 is the strongest so far described for any disease. With the help of psychosocial support, therapeutic naps, and medications, the patient with narcolepsy may be able to lead a normal life. Methylphenidate and imipramine are the two most widely used drugs for the treatment of daytime somnolence and cataplexy, respectively.

Polyurethane internal ureteral stents in treatment of stone patients: morbidity related to indwelling times

The morbidity and complications associated with use of internal polyurethane ureteral stents in a series of 290 stone patients treated endourologically or with extracorporeal shock wave lithotripsy were retrospectively reviewed. Of the 299 stents retrieved 141 were also tested for patency to relate the rate of luminal blockage with stent caliber, indwelling time and clinical evidence of obstruction in the stented tract. Stent indwelling times ranged from a few days to 18 months: 11.3% were indwelling longer than 6 months and 1.9% were lost to followup. Incrustation occurred in 9.2% of the stents retrieved before 6 weeks, 47.5% indwelling 6 to 12 weeks and 76.3% thereafter. In 19 cases over-all (6.4%) an auxiliary procedure was required to decrease incrusted stone burden and enable stent retrieval. Other complications included stent migration (3.7%), infection (6.7%) and breakage (0.3%). Despite a 30% rate of luminal blockage in stents retrieved after indwelling times up to 3 months, the incidence of clinical obstruction in stented tracts up to 3 months was 4%, confirming other reports that significant urine flow occurs around rather than through hollow, vented stents. Our findings underline the importance of restricting the use of stents to stone patients who will be reliable at followup. Morbidity was minimal if stent indwelling times did not exceed 6 weeks.

Sequence effect on incision by (A)BC excinuclease of 4NQO adducts and UV photoproducts

Nucleotide excision repair in Escherichia coli is initiated by (A)BC excinuclease, an enzyme which incises DNA on both sides of bulky adducts and removes the damaged nucleotide as a 12-13 base long oligomer. The incision pattern of the enzyme was examined using DNA modified by 4-nitroquinoline 1-oxide (4NQO) and UV light. Similar to the cleavage pattern of UV photoproducts and other bulky adducts, the enzyme incises the 8th phosphodiester bond 5' and 5th phosphodiester bond 3' to the 4NQO-modifed base, primarily guanine. The extent of DNA damage by these agents was determined using techniques which quantitatively cleave the DNA or stop at the site of the adduct. By comparison of the intensity of gel bands created by (A)BC excinuclease and the specific cleavage at the damaged site, the efficiency of (A)BC excinuclease incision at 13 different 4NQO-induced adducts and 13 different photoproducts was determined by densitometric scanning. In general, incisions made at 4NQO-induced adducts are proportional to the extent of damage, though the efficiency of cutting throughout the sequence tested varies from 25 to 75%. Incisions made at pyrimidine dimers are less efficient than at 4NQO-adducts, ranging from 13 to 65% incision relative to modification, though most are around 50%. The two (6-4) photoproducts within the region tested are incised more efficiently than any pyrimidine dimer.

Role of carrier ligand in platinum resistance in L1210 cells

We have examined the effect of carrier ligands on platinum accumulation, incorporation of platinum into DNA, cytotoxicity of Pt-DNA adducts, and repair of Pt-DNA adducts in three L1210 cell lines: L1210/0, which is sensitive to most types of platinum compounds; L1210/DDP, which is resistant to platinum compounds with the ethylenediamine (en) carrier ligand but sensitive to those with the diaminocyclohexane (dach) ligand; and L1210/DACH, which is resistant to dach-Pt compounds but sensitive to en-Pt compounds. There was a selective decrease in accumulation of dach-Pt in the L1210/DACH line and of en-Pt in the L1210/DDP line. Intracellular dach-Pt was incorporated into DNA to a lesser extent than en-Pt in both resistant cell lines. Cytotoxicity of en-Pt adducts was less than that of dach-Pt adducts in the L1210/DDP line, while the reverse was true in the L1210/DACH line. Increased repair was seen in both resistant cell lines; a carrier ligand effect was seen only in the L1210/DDP line, which showed a greater initial rate of repair for en-Pt than dach-Pt adducts. These data suggest that carrier ligand effects seen in resistant cell lines may be due, in part, to differences in accumulation of platinum, repair of Pt-DNA adducts, and tolerance of Pt-DNA adducts.

On the industrialization of small towns in Pakistan

"Migration to large metropolitan cities in Pakistan from rural areas and small towns has put enormous pressure on those cities and created many socio-economic and demographic problems. This article suggests that, in conjunction with other steps, many smaller towns should be developed and industrialized to ease the pressure on the larger cities, as has been done in other areas of the world."

Critique of the Dornier HM3 lithotripter as a clinical algesimeter

The power and nociceptive intensity of shock waves generated by the Dornier HM3 extracorporeal shock wave lithotripter (ESWL) are voltage dependent and suited to algesimetry in a controllable voltage range of 8-30 kV. Fidelity of the HM3 as an algesimeter was tested by: (1) In vitro measurements of shock pressure at voltages between 14 and 30 kV were recorded by a force transducer at the point of clinical focus. (2) Unanaesthetized volunteer (n = 5) assessment and VAS pain scores of shocks in the range of 10-24 kV, yielding highly significant correlations between blinded randomized shock voltage (r = 0.88), and VAS scores (r = 0.84). (3) Voltage-tolerance curves generated from 33 ASA class 1 or 2 patients undergoing ESWL treatment under epidural analgesia with 0.125% bupivacaine, fortified with a bolus epidural dose of 100 micrograms fentanyl if pain arose during treatment. Voltage tolerance was increased by 50% after an epidural bolus of 100 micrograms fentanyl (P less than 0.001). The respiratory consequences of epidural fentanyl were assessed by changes of respiratory rate and rhythm recorded from capnographic tracings of expired carbon dioxide. This study indicates that the Dornier HM3 system provides a valuable opportunity to conduct precise, quantitative measurements of induced deep truncal pain, as well as the effectiveness and respiratory cost of analgesic interventions directly applicable to the safe management of acute pain.

Effect of the diaminocyclohexane carrier ligand on platinum adduct formation, repair, and lethality

Platinum compounds with the diaminocyclohexane (dach) carrier ligand are of particular interest because cell lines that have developed resistance to platinum compounds in general often retain sensitivity to dach-platinum compounds, suggesting that the dach carrier ligand affects the formation, repair, or lethality of platinum-DNA adducts. The effect of the dach ligand on platinum adduct formation was assessed by using the (HaeIII-HindIII)146 fragment of pBR322 treated to give equal amounts of dach- or ethylene-diamine-platinum adducts. The sites of adduct formation were mapped by digestion with Escherichia coli ABC excinuclease. There were no significant effects of the dach carrier ligand on the types or sites of platinum adduct formation. The effect of the dach ligand on platinum adduct repair was determined by using synthetic oligomers designed to have single, specific platinum adducts (G monoadduct; GG, AG, or GNG diadduct) with either the dach or ethylenediamine (en) carrier ligand. These adducts differed significantly in their ability to serve as substrates for ABC excinuclease with GNG greater than or equal to G greater than AG greater than GG. The dach carrier ligand had little effect on the recognition of AG and GG adducts by ABC excinuclease, but significantly improved the ability of ABC excinuclease to excise G monoadducts and GNG diadducts. These data suggest that if the carrier ligand has any effect on the repair of platinum adducts, it is more likely to exert that effect on the repair of platinum monoadducts or GNG diadducts rather than on the more abundant AG or GG diadducts. [14C]Thiourea incorporation was used to quantitate the rate of monoadduct to diadduct conversion.(ABSTRACT TRUNCATED AT 250 WORDS)

Synapse formation on quail trochlear neurons transplanted in duck embryos before naturally occurring motor neuron death

About half of the trochlear motor neurons in duck and quail embryos die during normal development. In a previous study the role of target muscle in controlling the number of surviving motor neurons was investigated by reducing the number of neurons innervating the muscle. This was accomplished by removing the midbrain of the duck embryo and grafting in its place the midbrain of the quail embryo before motor neuron death begins. It was observed that the number of surviving trochlear motor neurons in the quail-duck chimera embryos was not significantly different from that of the normal quail. The present investigation was undertaken to determine whether trochlear motor neurons in the chimera embryos received afferent synapses. Brains of duck, quail and chimera embryos on days 16 and 20 were processed for electron microscopical observations. Synapses formed on motor neurons of the chimera embryos. Surprisingly, synapses on motor neurons of quail differed from those of duck, both qualitatively and quantitatively. Synapses on the motor neurons of the chimera embryos developed in a fashion similar to that for the duck motor neurons. Our failure to rescue trochlear motor neurons in the chimera embryos suggests that the developing motor neurons may respond to a larger target muscle only if they received a normal complement of afferent synaptic input.

Purification and properties of Methanobacterium thermoautotrophicum DNA photolyase

We have purified DNA photolyase from the autotrophic anaerobic archaebacterium Methanobacterium thermoautotrophicum to near homogeneity by a two-column affinity chromatography. The purified enzyme has an Mr = 60,000 and shows near UV absorption peak at 440 nm and a fluorescence emission maximum at 462 nm indicating that it contains 8-hydroxy-5-deazaflavin (coenzyme F420) as an intrinsic chromophore. The photolyase binds with high specificity to thymine dimer in DNA with an equilibrium binding constant, KA = 1.4 x 10(9) M-1, and a dissociation rate constant, koff = 1.4 x 10(-4) s-1 (t1/2 = 43 min). Despite 6-fold higher affinity compared to the folate-containing Escherichia coli photolyase the two enzymes apparently contact the same phosphates around the thymine dimer: the phosphate immediately 5' and the three phosphates immediately 3' to the dimer on the damaged strand and the phosphate across from the dimer in the minor groove on the complementary strand. The absolute action spectrum of the Methanobacterium photolyase in the 400-500-nm region closely matches the absorption of the enzyme-bound F420. The quantum yield (phi) over this region is constant and is approximately 0.2. The value is measurably smaller than the quantum yields reported for other DNA photolyases.

Epinephrine and fentanyl as adjuvants to 0.5% bupivacaine for epidural analgesia

The analgesic and respiratory effects of epidural 0.5% bupivacaine were studied in four groups of patients (n = 170) undergoing percutaneous nephrolithotripsy (PNL). Group 1 patients (n = 42) received 0.5% bupivacaine. Group 2 patients (n = 42) received 0.5% bupivacaine with 1:200,000 epinephrine. Group 3 patients (n = 42) received 0.5% bupivacaine plus 100 micrograms epidural fentanyl, and Group 4 patients (n = 44) received 0.5% bupivacaine plus fentanyl plus epinephrine. Intraoperative pain occurred in anatomically adequate segmental blockade in 15 patients from Groups 1 and 2, but in none from Groups 3 and 4. Analgesia was restored by 100 micrograms epidural fentanyl, and motor block appeared to be enhanced. The addition of epinephrine increased the intensity of motor block but not analgesia. Respiratory frequency was slower and respiratory rhythm more irregular in Group 3 than within the other groups. SaO2 decreased to 89% or lower in eight cases, and oxygen supplementation was required. It is concluded that PNL may be safely conducted under epidural analgesia when reinforced by epidural fentanyl while breathing air, provided SaO2 is monitored continuously; otherwise, oxygen supplementation should be provided.

Human nucleotide excision repair in vitro: repair of pyrimidine dimers, psoralen and cisplatin adducts by HeLa cell-free extract

We searched for nucleotide excision repair in human cell-free extracts using two assays: damage-specific incision of DNA (the nicking assay) and damage-stimulated DNA synthesis (the repair synthesis assay). HeLa cell-free extract prepared by the method of Manley et al. (1980) has a weak nicking activity on UV irradiated DNA and the nicking is only slightly reduced when pyrimidine dimers are eliminated from the substrate by DNA photolyase. In contrast to the nicking assay, the extract gives a strong signal with UV irradiated substrate in the repair synthesis assay. The repair synthesis activity is ATP dependent and is reduced by about 50% by prior treatment of the substrate with DNA photolyase indicating that this fraction of repair synthesis is due to removal of pyrimidine dimers by nucleotide excision. Psoralen and cisplatin adducts which are known to be removed by nucleotide excision repair also elicited repair synthesis activity 5-10 fold above the background synthesis. When M13RF DNA containing a uniquely placed psoralen adduct was used in the reaction, complete repair was achieved in a fraction of molecules as evidenced by the restoration of psoralen inactivated KpnI restriction site. This activity is absent in xeroderma pigmentosum group A cells. We conclude that our cell-free extract contains the human nucleotide excision repair enzyme activity.

Influence of Dornier HM3 system on respiration during extracorporeal shock-wave lithotripsy

Patients undergoing extracorporeal shock-wave lithotripsy (ESWL) for renal stones in the Dornier HM3 apparatus are immersed to the clavicles in water and anchored by abdominal and leg restraining straps. The respiratory effects of this system and sedation with midazolam were studied in 70 awake patients anesthetized with epidural blockade. On immersion, surface abdominal pressure and respiratory frequency (f) increased. Tidal volume (VT) and arterial saturation (SaO2) decreased. After intravenous midazolam 0.045 mg/kg body weight, VT decreased further to 35% below pre-immersion values and stone excursions measured by fluoroscopy diminished by more than 50%; reduction of VT and stone excursions were linearly correlated (R = 0.45). SaO2 declined sharply to 6.1% (range -1.5-13.8%) below pre-immersion values, whereas end-tidal CO2 (PETCO2) increased more slowly and f remained above the pre-immersion rate. In three patients, SaO2 decreased to below 85% but was rapidly restored to 98-100% by oxygen administration. The respiratory effects of sedative drugs are exaggerated by the Dornier HM3 system, and continuous monitoring of gas exchange and appropriate oxygen administration are recommended in patients receiving regional anesthesia and sedation.