VEGF enhances functional improvement of postinfarcted hearts by transplantation of ESC-differentiated cells.

Despite considerable advances in medicine, the incidence of heart failure remains high in patients after myocardial infarction (MI). This study investigated the effects of engrafted early-differentiated cells (EDCs) from mouse embryonic stem cells, with or without transfection of vascular endothelial growth factor (VEGF) cDNA (phVEGF(165)), on cardiac function in postinfarcted mice. EDCs were transfected with green fluorescent protein (GFP) cDNA and transplanted into infarcted myocardium. Compared with the MI mice receiving cell-free medium, cardiac function was significantly improved in the MI mice 6 wk after transplantation of EDCs. Moreover, improvement of heart function was significantly greater in the mice implanted with EDCs overexpressing VEGF (EDCs-VEGF) than with EDCs alone. Frozen sections of infarcted myocardium with EDCs or EDCs-VEGF transplantation showed GFP-positive tissue. The area with positive immunostaining for cardiac troponin I and alpha-myosin heavy chain was larger in injured myocardium with EDCs or EDCs-VEGF transplantation than with medium injection. Transplantation of EDCs or EDCs-VEGF significantly increased the number of blood vessels in the MI area. However, the density of capillaries was significantly higher in the EDCs-VEGF animals than in the EDC mice. Double staining for GFP and connexin-43 was positive in injured myocardium with EDC transplantation. Our data demonstrate that engrafted EDCs or EDCs-VEGF regenerated cardiac tissue and significantly improved cardiac function in postinfarcted hearts. The novel EDCs-VEGF synergistic approach may have an important impact on future cell therapy for patients experiencing MI or heart failure.     

Novel anti-HIV peptides containing multiple copies of artificially designed heptad repeat motifs

The peptidic anti-HIV drug T20 (Fuzeon) and its analog C34 share a common heptad repeat (HR) sequence, but they have different functional domains, i.e., pocket- and lipid-binding domains (PBD and LBD, respectively). We hypothesize that novel anti-HIV peptides may be designed by using artificial sequences containing multiple copies of HR motifs plus zero, one or two functional domains. Surprisingly, we found that the peptides containing only the non-natural HR sequences could significantly inhibit HIV-1 infection, while addition of PBD and/or LBD to the peptides resulted in significant improvement of anti-HIV-1 activity. These results suggest that these artificial HR sequences, which may serve as structural domains, could be used as templates for the design of novel antiviral peptides against HIV and other viruses with class I fusion proteins.     

Mechanism and dynamics of translesion DNA synthesis catalyzed by the Escherichia coli Klenow fragment

Translesion DNA synthesis represents the ability of a DNA polymerase to incorporate and extend beyond damaged DNA. In this report, the mechanism and dynamics by which the Escherichia coli Klenow fragment performs translesion DNA synthesis during the misreplication of an abasic site were investigated using a series of natural and non-natural nucleotides. Like most other high-fidelity DNA polymerases, the Klenow fragment follows the "A-rule" of translesion DNA synthesis by preferentially incorporating dATP opposite the noninstructional lesion. However, several 5-substituted indolyl nucleotides lacking classical hydrogen-bonding groups are incorporated approximately 100-fold more efficiently than the natural nucleotide. In general, analogues that contain large substituent groups in conjunction with significant pi-electron density display the highest catalytic efficiencies ( k cat/ K m) for incorporation. While the measured K m values depend upon the size and pi-electron density of the incoming nucleotide, k cat values are surprisingly independent of both biophysical features. As expected, the efficiency by which these non-natural nucleotides are incorporated opposite templating nucleobases is significantly reduced. This reduction reflects minimal increases in K m values coupled with large decreases in k cat values. The kinetic data obtained with the Klenow fragment are compared to that of the high-fidelity bacteriophage T4 DNA polymerase and reveal distinct differences in the dynamics by which these non-natural nucleotides are incorporated opposite an abasic site. These biophysical differences argue against a unified mechanism of translesion DNA synthesis and suggest that polymerases employ different catalytic strategies during the misreplication of damaged DNA.     

A novel diquinolonium displays preclinical anti-cancer activity and induces caspase-independent cell death

Quinolines are a class of chemical compounds with emerging anti-cancer properties. Here, we tested the activity of series of quinolines and quinoline-like molecules for anti-cancer activity and identified a novel diquinoline, 1-methyl-2-[3-(1-methyl-1,2-dihydroquinolin-2-yliden)prop-1-enyl]quinolinium iodide (Q²). Q² induced cell death in leukemia, myeloma, and solid tumor cell lines with LD50s in the low to submicromolar range. Moreover, Q² induced cell death in primary acute myeloid leukemia (AML) cells preferentially over normal hematopoietic cells. In a mouse model of leukemia, Q² delayed tumor growth. Mechanistically, Q² induced cell death through caspase independent mechanisms. By electron microscopy, Q² increased cytoplasmic vacuolization and mitochondrial swelling. Potentially consistent with the induction of autophagic cell death, Q² treatment led to a punctate distribution of LC3 and increased MDC staining. Thus, Q² is a novel quinolinium with preclinical activity in malignancies such as leukemia and myeloma and warrants further investigation.     

Leydig cell hyperplasia revealed by gynecomastia

Leydig cell tumors are rare and represent 1% to 3% of all tumors of the testis. Leydig cell tumors affect males at any age, but there are 2 peak periods of incidence: between 5 and 10 years and between 25 and 35 years. Their main clinical presentation is a testicular mass associated with endocrinal manifestations that are variable according to age and appearance of the tumor. Our patient, a 17-year-old adolescent, presented with an isolated and painless hypertrophy of the right mammary gland. Clinical examination found gynecomastia and no testicular mass. Hormonal levels and tumor markers were normal. Testicular sonography showed an ovular and homogeneous right intratesticular mass 6 mm in diameter. We treated the patient with an inguinal right orchidectomy. The anatomopathological study found a nodule of Leydig cell hyperplasia. The patient recovered without recurrence at 8-month follow-up. The patient opted for mammoplasty 2 months after his orchidectomy rather than wait for the spontaneous gradual regression of his gynecomastia, which requires at least 1 year. Leydig cell hyperplasia manifests in the adult by signs of hypogonadism, most frequently gynecomastia. Although many teams prefer total orchidectomy because of the diagnostic difficulty associated with malignant forms, simple subcapsular orchidectomy should become the first-line treatment, provided it be subsequently followed by close surveillance, as it preserves maximum fertility, and these tumors usually resolve favorably.     

Studying health-seeking behaviours: collecting reliable data, conducting comprehensive analysis

There is certainly a growing need to justify the significance of studying health-seeking behaviours for designing advocacy campaigns, lobbying for a policy shift and convincing donors to invest in priority areas. Moreover, policymakers need to be encouraged to design evidence-based policies that take into account information relating to health-promoting, -seeking and -utilization behaviour and the factors determining these behaviours. This paper primarily covers the 'methodology' used in the study of health-seeking behaviours and determinants of health services utilization in a predominantly rural district of Pakistan. The paper substantiates that this methodology is comprehensive and reliable, and there is potential for replicating this in similar settings. The approach of Kroeger in his research on the study of health-seeking behaviours, particularly in developing countries, provides the most holistic framework for examining, analysing and interpreting factors and determinants of health-seeking behaviours and health services utilization in developing countries. This study endeavoured to validate Kroeger's framework in a Pakistani setting, exploring all the factors listed through mixed method research, and qualitative supplemented by representative quantitative enquiry. This approach has also helped in understanding the inter-relationship of various factors and drivers of health-seeking behaviours from all angles.     

A syndromic form of autosomal recessive congenital microcephaly (Jawad syndrome) maps to chromosome 18p11.22–q11.2

We report a consanguineous Pakistani family with seven affected individuals showing a syndromic form of congenital microcephaly. Clinical features of affected individuals include congenital microcephaly with sharply slopping forehead, moderate to severe mental retardation, anonychia congenita, and digital malformations. By screening human genome with microsatellite markers, this autosomal recessive condition was mapped to a 25.2 cM interval between markers D18S1150 and D18S1100 on chromosome 18p11.22–q12.3. However, the region of continuous homozygosity between markers D18S1150 and D18S997 spanning 15.33 cM, probably define the most likely candidate region for this condition. This region encompasses a physical distance of 12.03 Mb. The highest two-point LOD score of 3.03 was obtained with a marker D18S1104 and multipoint score reached a maximum of 3.43 with several markers. Six candidate genes, CEP76, ESCO1, SEH1L, TUBB6, ZNF519, and PTPN2 were sequenced, and were found to be negative for functional sequence variants.