Diagnostic Evaluation of Polycythemia Vera at High Altitude.

BACKGROUND: Polycythemia is a common medical problem, frequently acquired and reactive to secondary conditions. High-altitude-associated hypoxia contributes to the greater prevalence of polycythemia at altitude. Primary clonal polycythemia vera (PV), even though it is rare, requires a different therapeutic approach. Suspicion of PV usually drives the diagnostic workup of polycythemia. METHODS: In this retrospective lab record study, we collected all JAK2 tests requested over a three-year period. We analyzed requests that were made for the evaluation of polycythemia. Complete blood count (CBC) and imaging of the abdomen were collected. RESULTS: Out of 208 total requests, 136 were for the purpose of polycythemia evaluation. JAK2 mutation was positive (confirming the presence of PV) in 22 (16.7%) cases. PV patients have the usual demographics reported elsewhere. Additionally, PV patients exhibit distinct hemogram results featuring leukocytosis, thrombocytosis, and hypochromic microcytic red blood cells (RBCs) related to the associated iron deficiency. CONCLUSIONS: Many patients with polycythemia at altitude might be unnecessarily considered for an evaluation of PV, if hemoglobin/hematocrit is the sole deciding criterion. PV patients have a distinct CBC pattern that can be exploited to better select patients with polycythemia for further evaluation and thus reduce unnecessary workups.

Overuse Ordering Serum Vitamin B12: A Call for Appropriate Ordering Guidelines Based on a Single Institutional Experience.

OBJECTIVE: Vitamin B12 is an essential nutrient for numerous functions in the human body. As such, many clinical scenarios justify assaying serum B12; however, there are no evidence-based guidelines available for determining when to order B12 tests. Here we investigate B12 assay ordering patterns to identify methods of enhancing efficiency and minimizing inappropriate requests. METHODS: All serum B12 requests within the year spanning July 2018 to June 2019 were reviewed using the hospital's health information system. These amounted to 3,400 requests, of which data from the first 1,000 were evaluated. Patient demographics, hematological data, serum folate, and ferritin were extracted from the electronic requests. Physician identity and request reason were retrieved where available. RESULTS: Of the 877 B12 requests for which patient age was available, the majority (80.3%) were for young and middle-aged patients. Interestingly, serum B12 was low in only a quarter of the 1,000 reviewed requests; the remaining three quarters had normal levels. Folate, which can be ordered with vitamin B12, was tested in 82 cases, of which only two (2.4%) had folate deficiency. CONCLUSION: This study highlights a high occurrence of improper ordering of vitamin B12 assays, indicating a need for revised guidelines to promote optimal test ordering.

The attitude of the Public Toward Social History Taking in Southern Saudi Arabia.

Background: Social history taking is an important element of a medical interview. No previous studies, however, addressed public attitudes regarding social history taking in Saudi Arabia. Objective: This study explores public attitudes about the importance of social history taking by doctors in Southern Saudi Arabia. Methods: A cross-sectional study was conducted to collect public opinion about social history taking using a self-administered questionnaire. Social history taking was defined as questions about general sociodemographics (job, income, marital status, housing conditions, and animal contact) and social habits (travel, smoking, alcohol drinking, illicit drug use, and sexual history). Descriptive statistics were conducted, along with a comparison between categorical variables. Results: A total of 510 respondents completed the questionnaire, of which 381 (74.7%) had a medical history taken before. A complete social taking was not obtained from those with medical history previously taken. Marital status (73.2%), smoking (49.1%), and occupation (32.8%) were the commonest inquiries, while income (3.7%) and sexual history (6.6%) were the least. Most respondents had no reservations about answering questions about their social history. Among the general demographic questions, job and marital status were more likely to be answered, whereas income and housing inquiries were less likely to be answered. Among social habits, sexual history followed by illicit drug use and alcohol drinking inquiries were less likely to be answered. Conclusion: Detailed social history taking is uncommon among doctors. The public is open to discussing their social status and habits. However, questions involving income, housing, and some social habits like illicit drugs, alcohol, and sexual history are less likely to be faithfully reported and thus need to be handled appropriately. It is crucial for healthcare providers to approach social history taking with sensitivity and respect and to create a private environment for patients where they can freely and accurately share their social histories.

DLK-Dependent Biphasic Reactivation of Herpes Simplex Virus Latency Established in the Absence of Antivirals.

Understanding the molecular mechanisms of herpes simplex virus 1 (HSV-1) latent infection and reactivation in neurons requires the use of in vitro model systems. Establishing a quiescent infection in cultured neurons is problematic, as any infectious virus released can superinfect the cultures. Previous studies have used the viral DNA replication inhibitor acyclovir to prevent superinfection and promote latency establishment. Data from these previous models have shown that reactivation is biphasic, with an initial phase I expression of all classes of lytic genes, which occurs independently of histone demethylase activity and viral DNA replication but is dependent on the cell stress protein DLK. Here, we describe a new model system using HSV-1 Stayput-GFP, a reporter virus that is defective for cell-to-cell spread and establishes latent infections without the need for acyclovir. The establishment of a latent state requires a longer time frame than previous models using DNA replication inhibitors. This results in a decreased ability of the virus to reactivate using established inducers, and as such, a combination of reactivation triggers is required. Using this system, we demonstrate that biphasic reactivation occurs even when latency is established in the absence of acyclovir. Importantly, phase I lytic gene expression still occurs in a histone demethylase and viral DNA replication-independent manner and requires DLK activity. These data demonstrate that the two waves of viral gene expression following HSV-1 reactivation are independent of secondary infection and not unique to systems that require acyclovir to promote latency establishment. IMPORTANCE Herpes simplex virus-1 (HSV-1) enters a latent infection in neurons and periodically reactivates. Reactivation manifests as a variety of clinical symptoms. Studying latency and reactivation in vitro is invaluable, allowing the molecular mechanisms behind both processes to be targeted by therapeutics that reduce the clinical consequences. Here, we describe a novel in vitro model system using a cell-to-cell spread-defective HSV-1, known as Stayput-GFP, which allows for the study of latency and reactivation at the single neuron level. We anticipate this new model system will be an incredibly valuable tool for studying the establishment and reactivation of HSV-1 latent infection in vitro. Using this model, we find that initial reactivation events are dependent on cellular stress kinase DLK but independent of histone demethylase activity and viral DNA replication. Our data therefore further validate the essential role of DLK in mediating a wave of lytic gene expression unique to reactivation.

Effect of Altitude on Hemoglobin and Red Blood Cell Indices in Adults in Different Regions of Saudi Arabia.

Purpose: Complete blood count (CBC) is a commonly used blood test for health checks. This study was conducted to compare CBC from two different altitudes and from sea-level populations in order to suggest correction factor for altitude-related increment on the hemoglobin and red blood cell indices. Patients and Methods: In this retrospective lab records study, large datasets of CBCs over 5-year period were screened from three different regions of Saudi Arabia, Jeddah (a coastal city), Taif City located at 1879 m above sea level, and Abha City at located 2270 m above sea level. Descriptive analysis and significance testing of the CBC variables at different altitude were compared. Results: A total of 57,059 participants were included for final analysis. Mean hemoglobin (Hb) concentration (g/dL) was 14.81 for men and 13.77 for women at sea level, whereas Hb concentrations were 15.35 and 14.19 for men and women residing at Taif City, respectively, and 15.40 and 14.71 for men and women at Abha City, respectively. Hemoglobin and other red cell indices were significantly different among men and women across different altitude, except for mean corpuscular volume (MCV). The MCV 95th percentile range was lower at sea level and both altitudes as compared to current reference range (76-91 fL vs 81-98 fL). Conclusion: Although altitude-associated increment in Hb concentration was evident in both men and women, it was lower than as suggested by World Health Organization and Centers for Disease and Control. Results of this study can also be used to derive new CBC reference intervals for Saudi residents living at high altitude. A correction factor (ΔHb) of 0.30 g/dL per 1000 m altitude is suggested to be used in adult population living at high altitudes in Saudi Arabia which should help better define anemia and polycythemia at altitude.

Efficacy and Safety of Endoscopic Esophageal Dilatation in Pediatric Patients with Esophageal Strictures.

MATERIALS AND METHODS: In this retrospective cross-sectional single center study, records of patients with esophageal strictures presented to the pediatric department, Salmaniya Medical Complex, Bahrain, in the period between 1995 and 2019 were reviewed. Demographic data, indications of endoscopic dilatations, the procedure success rate, and possible complications were assessed. RESULTS: Forty-six children were found to have esophageal strictures. Twenty-five (54.3%) patients were males. Most patients presented during infancy (86.5%, 32/37 patients). Twenty-six (56.5%) patients required 88 dilatation sessions, while the remaining 20 (43.5%) patients did not require dilatations. The median number of dilatation sessions per patient was three (interquartile range = 2-5). Savary-Gilliard bougienages were the main dilators used (80.8%, 21/26 patients). Anastomotic stricture (post esophageal atresia/tracheoesophageal fistula repair) was the main cause of esophageal strictures and was found in 35 (76.1%) patients. Patients with nonanastomotic strictures had more frequent dilatations compared to those with anastomotic strictures (P = 0.007). The procedure success rate was 98.8%. Yet, it was operator dependent (P = 0.047). Complete response to dilatation was found in 18 (69.2%) patients, satisfactory in seven (26.9%), and an inadequate response in one (3.9%). Those with satisfactory responses still require ongoing dilatations based on their symptoms and radiological and endoscopic findings. No perforation or mortality was reported. Patients with dilatations had more recurrent hospitalization (P < 0.0001), more dysphagia (P = 0.001), but shorter hospital stay (P = 0.046) compared to those without dilatations. Surgical intervention was required in one patient with caustic strictures. The median follow-up period was six years (interquartile range = 2.25-9.0). CONCLUSIONS: Endoscopic esophageal dilatation in children with esophageal strictures is effective and safe. Yet, it was operator dependent. Nonanastomotic strictures require more dilatations compared to anastomotic strictures. Findings of this study are comparable to those reported worldwide.

Isolated Neutropenia/Benign Ethnic Neutropenia: A Common Clinical and Laboratory Finding in Southern and Western Saudi Arabia.

OBJECTIVE: Isolated mild neutropenia is a common clinical problem in some ethnicities including Arabs and Middle Eastern population. The current study aims to authenticate the prevalence of isolated neutropenia in Southern and Southwestern Saudi Arabia, explore the effect of altitude or regional differences and to suggest a new reference range for neutrophil count. METHODS: In this retrospective cross-sectional study, laboratory results of a commercial laboratory were screened over a period of 5 years (2016-2020) in seven different cities of different altitudes in South and southwestern Saudi Arabia. Participants' laboratory investigations were reviewed and excluded for any abnormal complete blood count, renal profile, liver profile, lipid profile, thyroid function test, fasting blood glucose, or HbA1c findings. Descriptive analysis and 95th percentile range were calculated using standard statistical methods. RESULTS: A total of 91,880 complete blood count results were included in the final analysis. Isolated neutropenia was common laboratory finding, with a prevalence ranging from 11% to 23%. The 2.5th percentile of the neutrophil count was lower than currently utilized 1.5×109/L in all studied seven cities. CONCLUSION: Mild to moderate neutropenia is common in Southern and Southwestern Saudi Arabia. Benign ethnic neutropenia (BEN) likely explains this high prevalence. Since BEN has no clinical significance, the reference range for normal neutrophil counts needs to be adjusted to reflect the effect of BEN.

The Prevalence of Isolated Neutropenia at High Altitude in Southern Saudi Arabia: Does Altitude Affect Leucocyte Count?

INTRODUCTION: Isolated neutropenia is a common problem in hematology practice. Benign ethnic neutropenia (BEN) is the common form of neutropenia worldwide and it affects mainly African and Middle Eastern ethnicities. Most cases of isolated mild and moderate neutropenia are benign and associated with no clinical significance. The aim of this study was to estimate the prevalence of isolated neutropenia at high-altitude southern Saudi Arabia. METHODS: A large dataset of complete blood counts (CBCs) was analyzed for walk-in patients of both genders, of age ranges from 12 to 60 years doing blood tests at a commercial lab for high altitude - 2,270 meters above sea level - (HA) group, and from sea level SL group. Abnormal biochemical or CBC results were excluded before analysis. RESULTS: For HA group, 3123 CBCs were analyzed and for SL group 18,427 CBCs were analyzed. The prevalence of mild neutropenia, defined as absolute neutrophil count (ANC) in the range of 1.0-.5× 109/L, was 12.4% (n=399) versus 5.6% (n=1025), while moderate neutropenia, defined as ANC of 0.5-1 × 109/L, was present 6% (n=191) versus 1.45% (n=269) in the high altitude and sea level groups, respectively. Severe neutropenia, defined as neutrophil count less than 0.5-1 × 109/L, was rare in both groups. CONCLUSION: Isolated neutropenia is common in Saudis living at high altitude. While benign ethnic neutropenia (BEN) is thought to be the major contributing factor to this high prevalence, other factors including environmental factors and altitude are possible contributing factors along with underlying ethnic neutropenia.

The pattern of iron deficiency with and without anemia among medical college girl students in high altitude southern Saudi Arabia.

INTRODUCTION: The prevalence of iron deficiency, latent and symptomatic, is heterogeneous worldwide. In this study, we aim to explore the prevalence of iron deficiency, with and without anemia, among medical college females at the high Altitude Aseer region of Southwestern Saudi Arabia. METHODOLOGY: 200 female medical students were randomly sampled, between the ages of 19 and 27 years. Blood samples were collected for complete blood count (CBC) values and serum ferritin determination. Questionnaires were completed in order to collect demographics, medical history, and socioeconomic information of the participants. RESULTS: Prevalence of overall iron deficiency was high (63%, serum ferritin <20 µg/L, 52.5%, ferritin <15 µg/L). Anemia, adjusted for high altitude (defined as less than 13 g/dL was present in 41 participants (20.5%) and 12 (6.5%) have Hb <12 g/dL. Iron-deficiency anemia (Hb <13 g/dL and serum ferritin <15 µg/L) was present in 35 (17.5%). Personal and family history of anemia and poor animal product containing meals were positively correlated with the presence of iron deficiency state. Neither symptoms of anemia, nor the presence of menorrhagia correlate with the presence of iron deficiency anemia. CONCLUSION: Iron deficiency with and without anemia is a very common and condition in young females' population at high altitude. Implementing a lab method to screen for anemia on vulnerable populations is needed. Frequently asymptomatic, the primary care providers should maintain a high degree of suspicion in order to initiate screening for iron status.

Isotretinoin is active in the initial management of acute pro-myelocytic leukemia.

Pro-myelocytic acute leukemia (APL) is characterized by the proliferation of cells blocked at promyelocytic stage and ATRA is the choice of initial treatment because of the APL sensitivity to this compound. In this case study we report a 28-year-old man who presented to the Emergency Department with epistaxis, petechial rash, and fever. Laboratory tests revealed the presence of high white blood cell count with 60% blasts and evidence of coagulopathy. The diagnosis was confirmed later as APL. Because of the delayed transfer to the reference center and unavailability of ATRA initial treatment, the patient received isotretinoin, a related compound. The treatment was successfully implemented in the initial management of acute pro-myelocytic leukemia as patient condition improved. isotretinoin could be used as an alternative therapy for ATRA whenever the latter is not available. further research is needed to establish the appropriate doses and to assess the potential risk of differentiation syndromes.

Clinical Appropriateness of Serum Folate ordering pattern in a tertiary care hospital in Saudi Arabia.

Folate, also known as vitamin B9, is a co-factor necessary for DNA synthesis. Folate deficiency is associated mainly with hematological findings including megaloblastic anemia and pancytopenia. Many countries have mandated grain fortification with micronutrients including folic acid resulting in a reduced prevalence of folate deficiency. Saudi Arabia imports most of the grain products and folate is usually added after milling. There are no local studies to address the folate deficiency prevalence. In this study we aimed to analyse the clinical appropriateness of ordering practice of serum Folate level. METHOD: We reviewed all serum folate requests received at our laboratory in Aseer Central Hospital over one-year period (July 2018 June 2019). We collected patients' demographics from the electronic requests along with biochemical results of serum B12, ferritin and CBC results. We assessed appropriateness of orders against pre-specified criteria and applied statistical tests to explore for any association or significance. RESULTS: Serum folate requests from 614 patients were received during the study period. Serum B12 (543, 88%), and serum ferritin (511, 83%) were concurrently requested. The most common reason for request, when available, was anemia. Anemia was present in (313, 51%) of the subjects for which microcytic anemia was predominant (199, 63.5%), followed by normocytic anemia (101, 33%) and only 10 subjects had macrocytic anemia (3.2%). The most common hematinics' deficiency was ferritin (30%) followed by B12 (17.2%). Serum folate deficiency was low, observed in only 2.8%. Low folate levels were not significantly different between the group with anemia and the normal hemoglobin group. CONCLUSION: This study identifies a commonly inappropriate serum folate ordering practice that includes ordering all hematinics at the same visit without considering the possible anemia etiologies. The excessive requests might be related to doctors attempt to avoid multiple blood extractions and to try to reduce the time for diagnosis. These policies are generating unnecessary costs and time loss. Education, phasing out or restricting some tests and introducing laboratory policies like sample storing could help reduce unnecessary requests.

Targeting Nuclear Exporter Protein XPO1/CRM1 in Gastric Cancer.

Gastric cancer remains an unmet clinical problem in urgent need of newer and effective treatments. Here we show that the nuclear export protein, Exportin 1 (XPO1, chromosome region maintenance 1 or CRM1), is a promising molecular target in gastric cancer. We demonstrate significant overexpression of XPO1 in a cohort of histologically diverse gastric cancer patients with primary and metastatic disease. XPO1 RNA interference suppressed gastric cancer cell growth. Anti-tumor activity was observed with specific inhibitor of nuclear export (SINE) compounds (selinexor/XPOVIO), second-generation compound KPT-8602/eltanexor, KPT-185 and +ve control Leptomycin B in three distinct gastric cancer cell lines. SINE compounds inhibited gastric cancer cell proliferation, disrupted spheroid formation, induced apoptosis and halted cell cycle progression at the G1/S phase. Anti-tumor activity was concurrent with nuclear retention of tumor suppressor proteins and inhibition of colony formation. In combination studies, SINE compounds enhanced the efficacy of nab-paclitaxel in vitro and in vivo. More significantly, using non-coding RNA sequencing studies, we demonstrate for the first time that SINE compounds can alter the expression of non-coding RNAs (microRNAs and piwiRNAs). SINE treatment caused statistically significant downregulation of oncogenic miR-33b-3p in two distinct cell lines. These studies demonstrate the therapeutic significance of XPO1 in gastric cancer that warrants further clinical investigation.

Exacerbation of N-nitrosodiethylamine Induced Hepatotoxicity and DNA Damage in Mice Exposed to Chronic Unpredictable Stress.

Psychological stress contributes to increased susceptibility to a number of diseases including cancer. The present study was designed to assess the effect of chronic unpredictable stress on N-nitrosodiethylamine induced liver toxicity in terms of in vivo antioxidant status and DNA damage in Swiss albino mice. The animals used in this study were randomized into different groups based on the treatment with N-nitrosodiethylamine or chronic unpredictable stress alone and post-stress administration of N-nitrosodiethylamine. The mice were sacrificed after 12 weeks of treatment, and the status of major enzymatic and non-enzymatic antioxidants, liver function markers, lipid peroxidation and the extent of DNA damage were determined in circulation and liver tissues of all the groups. The N-nitrosodiethylamine treated group showed significantly compromised levels of the antioxidant enzymes, lipid peroxidation, and the liver function markers with enhanced DNA damage as compared to chronic unpredictable stress or control groups. A similar but less typical pattern observed in the chronic unpredictable stress treated mice. All the measured biochemical parameters were significantly altered in the group treated with the combination of chronic unpredictable stress and N-nitrosodiethylamine when compared to controls, or chronic unpredictable stress alone and/or N-nitrosodiethylamine alone treated groups. Thus, exposure to continuous, unpredictable stress conditions even in general life may significantly enhance the hepatotoxic potential of N-nitrosodiethylamine through an increase in the oxidative stress and DNA damage.

Simulating hypoxia-induced acidic environment in cancer cells facilitates mobilization and redox-cycling of genomic copper by daidzein leading to pro-oxidant cell death: implications for the sensitization of resistant hypoxic cancer cells to therapeutic challenges.

This study was conducted to investigate the mechanism of action involved in the anti-cancer activity of daidzein and identification of cancer specific micro-environment as therapeutic target of this secondary metabolite derived from soy. Our data indicated that daidzein induces cellular DNA breakage, anti-proliferative effects and apoptosis in a concentration-dependent manner. We demonstrated that such a daidzein-induced anti-cancer action involves a copper-dependant pathway in which endogenous copper is mobilized by daidzein and redox-cycled to generate reactive oxygen species which act as an upstream signal leading to pro-oxidant cell death. Further in the context of hypoxia being a resistant factor against standard therapies and that an effect secondary to hypoxia is the intracellular acidification, we show that the anticancer activity of daidzein is modulated positively in acidic pH but copper-specific chelator is still able to inhibit daidzein activity. Moreover, an experimental setup of hypoxia mimic (cobalt chloride) revealed an enhanced sensitivity of cancer cells to the cytotoxic effects of daidzein which was neutralized in the presence of neocuproine. The findings support a paradigm shift from the conventional antioxidant property of dietary isoflavones to molecules capable of initiating a pro-oxidant signaling mediated by reactive oxygen species. Further, the clinical relevance of such an action mechanism in cancer chemoprevention is also proposed. This study identified endogenous copper as a molecular target and acidic pH as a modulating factor for the therapeutic activity of daidzein against cancer. The evidence presented highlights the potential of dietary agents as adjuvants to standard therapeutic regimens.

The prooxidant action of dietary antioxidants leading to cellular DNA breakage and anticancer effects: implications for chemotherapeutic action against cancer.

Plant-derived dietary antioxidants have attracted considerable interest in recent past for their ability to induce apoptosis and regression of tumors in animal models. While it is believed that the antioxidant properties of these agents may contribute to lowering the risk of cancer induction by impeding oxidative injury to DNA, it could not account for apoptosis induction and chemotherapeutic observations. In this article, we show that dietary antioxidants can alternatively switch to a prooxidant action in the presence of transition metals such as copper. Such a prooxidant action leads to strand breaks in cellular DNA and growth inhibition in cancer cells. Further, the cellular DNA breakage and anticancer effects were found to be significantly enhanced in the presence of copper ions. Moreover, inhibition of antioxidant-induced DNA strand breaks and oxidative stress by Cu(I)-specific chelators bathocuproine and neocuproine demonstrated the role of endogenous copper in the induction of the prooxidant mechanism. Since it is well established that tissue, cellular, and serum copper levels are considerably elevated in various malignancies, such a prooxidant cytotoxic mechanism better explains the anticancer activity of dietary antioxidants against cancer cells.

Apogossypolone, derivative of gossypol, mobilizes endogenous copper in human peripheral lymphocytes leading to oxidative DNA breakage.

Gossypol is a polyphenolic aldehyde that is produced in the cotton plant. Since long it has been reported to possess antiproliferative activity against a variety of cancer cell lines as well as tumor regression in animal models. However, the toxicity of gossypol does not permit it to be an effective antitumor agent. One of the derivatives of gossypol to show promising results is apogossypolone. For example, it has been shown to specifically target tumor growth in hepatocellular carcinoma xenograft in nude mice without causing any damage to normal tissue. Using human peripheral lymphocytes, in this paper we show that both gossypol and its semi-synthetic derivative apogossypolone cause oxidative DNA breakage in these cells through the mobilization of endogenous copper ions. Such cellular DNA breakage is inhibited by copper specific chelator but nor by iron or zinc chelating agents. Similar results are obtained with isolated nuclei indicating that chromatin bound copper is mobilized in this reaction. Further, apogossypolone showed enhanced DNA breakage and increased oxidative stress in whole lymphocytes as compared with gossypol indicating that this is possibly the result of greater permeability of apogossypolone. It is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies. Therefore, cancer cells may be subject to greater electron transfer between copper ions and gossypol/apogossypolone to generate reactive oxygen species responsible for DNA cleavage. This may account for the preferential cytotoxicity of apogossypolone towards tumor cells.

Oral administration of copper to rats leads to increased lymphocyte cellular DNA degradation by dietary polyphenols: implications for a cancer preventive mechanism.

To account for the observed anticancer properties of plant polyphenols, we have earlier proposed a mechanism which involves the mobilization of endogenous copper ions by polyphenols leading to the generation of reactive oxygen species (ROS) that serve as proximal DNA cleaving agents and lead to cell death. Over the last decade we have proceeded to validate our hypothesis with considerable success. As a further confirmation of our hypothesis, in this paper we first show that oral administration of copper to rats leads to elevated copper levels in lymphocytes. When such lymphocytes with a copper overload were isolated and treated with polyphenols EGCG, genistein and resveratrol, an increased level of DNA breakage was observed. Further, preincubation of lymphocytes having elevated copper levels with the membrane permeable copper chelator neocuproine, resulted in inhibition of polyphenol induced DNA degradation. However, membrane impermeable chelator of copper bathocuproine, as well as iron and zinc chelators were ineffective in causing such inhibition in DNA breakage, confirming the involvement of endogenous copper in polyphenol induced cellular DNA degradation. It is well established that serum and tissue concentrations of copper are greatly increased in various malignancies. In view of this fact, the present results further confirm our earlier findings and strengthen our hypothesis that an important anticancer mechanism of plant polyphenols could be the mobilization of intracellular copper leading to ROS-mediated cellular DNA breakage. In this context, it may be noted that cancer cells are under considerable oxidative stress and increasing such stress to cytotoxic levels could be a successful anticancer approach.

Soy isoflavone genistein induces cell death in breast cancer cells through mobilization of endogenous copper ions and generation of reactive oxygen species.

SCOPE: Worldwide geographical variation in cancer incidence indicates a correlation between dietary habits and cancer risk. Epidemiological studies have suggested that populations with high isoflavone intake through soy consumption have lower rates of breast, prostate, and colon cancer. Isoflavone genistein in soybean is considered a potent chemopreventive agent against cancer. Although several mechanisms have been proposed, a clear anticancer action mechanism of genistein is still not known. METHODS AND RESULTS: Here, we show that the cytotoxic action of genistein against breast cancer cells involves mobilization of endogenous copper. Further, whereas the copper specific chelator neocuproine is able to inhibit the apoptotic potential of genistein, the molecules which specifically bind iron (desferroxamine mesylate) and zinc (histidine) are relatively ineffective in causing such inhibition. Also, genistein-induced apoptosis in these cells is inhibited by scavengers of reactive oxygen species (ROS) implicating ROS as effector elements leading to cell death. CONCLUSIONS: As copper levels are known to be considerably elevated in almost all types of cancers, in this proof-of-concept study we show that genistein is able to target endogenous copper leading to prooxidant signaling and consequent cell death. We believe that such a mechanism explains the anticancer effect of genistein as also its preferential cytotoxicity towards cancer cells.

Atomic structure of a fragment of human CD4 containing two immunoglobulin-like domains.

The structure of an N-terminal fragment of CD4 has been determined to 2.4 A resolution. It has two tightly abutting domains connected by a continuous beta strand. Both have the immunoglobulin fold, but domain 2 has a truncated beta barrel and a non-standard disulphide bond. The binding sites for monoclonal antibodies, class II major histocompatibility complex molecules, and human immunodeficiency virus gp120 can be mapped on the molecular surface.