IGF-1R inhibition enhances radiosensitivity and delays double-strand break repair by both non-homologous end-joining and homologous recombination.

Inhibition of type 1 insulin-like growth factor receptor (IGF-1R) enhances tumor cell sensitivity to ionizing radiation. It is not clear how this effect is mediated, nor whether this approach can be applied effectively in the clinic. We previously showed that IGF-1R depletion delays repair of radiation-induced DNA double-strand breaks (DSBs), unlikely to be explained entirely by reduction in homologous recombination (HR) repair. The current study tested the hypothesis that IGF-1R inhibition induces a repair defect that involves non-homologous end joining (NHEJ). IGF-1R inhibitor AZ12253801 blocked cell survival and radiosensitized IGF-1R-overexpressing murine fibroblasts but not isogenic IGF-1R-null cells, supporting specificity for IGF-1R. IGF-1R inhibition enhanced radiosensitivity in DU145, PC3 and 22Rv1 prostate cancer cells, comparable to effects of Ataxia Telangiectasia Mutated inhibition. AZ12253801-treated DU145 cells showed delayed resolution of γH2AX foci, apparent within 1 h of irradiation and persisting for 24 h. In contrast, IGF-1R inhibition did not influence radiosensitivity or γH2AX focus resolution in LNCaP-LN3 cells, suggesting that radiosensitization tracks with the ability of IGF-1R to influence DSB repair. To differentiate effects on repair from growth and cell-survival responses, we tested AZ12253801 in DU145 cells at sub-SF50 concentrations that had no early (⩽48 h) effects on cell cycle distribution or apoptosis induction. Irradiated cultures contained abnormal mitoses, and after 5 days IGF-1R-inhibited cells showed enhanced radiation-induced polyploidy and nuclear fragmentation, consistent with the consequences of entry into mitosis with incompletely repaired DNA. AZ12253801 radiosensitized DNA-dependent protein kinase (DNA-PK)-proficient but not DNA-PK-deficient glioblastoma cells, and did not radiosensitize DNA-PK-inhibited DU145 cells, suggesting that in the context of DSB repair, IGF-1R functions in the same pathway as DNA-PK. Finally, IGF-1R inhibition attenuated repair by both NHEJ and HR in HEK293 reporter assays. These data indicate that IGF-1R influences DSB repair by both major DSB repair pathways, findings that may inform clinical application of this approach.

Laparoscopically inserted button colostomy as a venting stoma and access port for the administration of antegrade enemas in African degenerative leiomyopathy.

African degenerative leiomyopathy (ADL) is a rare incurable disorder seen in African children, predominantly in southern and south-eastern Africa. ADL presents as chronic intestinal pseudo-obstruction. Management is traditionally conservative, with surgery restricted to the management of complications. We have placed Malone antegrade continence enema (MACE) stomas in the grossly dilated colon to vent accumulated gas and administer antegrade bowel enemas. This is done mainly for relief of gaseous distension and constipation in an attempt to provide symptomatic relief and improve quality of life. In this article, we present our preliminary results of laparoscopically assisted technique to insert a Mic-Key gastrostomy device as a 'button colostomy' in 8 patients over the past 6½ years.

Retrospective surveillance of intussusception in South Africa, 1998-2003.

BACKGROUND: Intussusception is a common gastrointestinal emergency in children and appears to have a somewhat different clinical spectrum in developing countries. Its etiology is still unclear, but a link to infective agents and viruses has been highlighted. This study aimed to assess the clinical spectrum and prevalence of intussusception in children from the diverse South African population. METHODS: Retrospective data were obtained from 9 participating pediatric referral units on the occurrence of intussusception in South African children (<14 years old) during a 6-year period (1998-2003). Results were correlated with national population statistics. Intussusception was anatomically classified into ileoileal, ileocolic, and colocolic types. The clinical features, management, outcome, and possible causes were examined. RESULTS: We reviewed the occurrence and clinical spectrum of intussusception in 423 children (age, 0-14 years) presenting with acute intussusception to 9 pediatric surgical centers. The mean duration of symptoms was 1.5 days, but a delayed presentation was common (median delay, 2.3 days). Intussusception occurred throughout the year, with a peak in the summer months. The majority of patients (89%) were <2 years old, and 78% presented at age 3-18 months of age. Crude population estimates indicate an occurrence of 1 case per 3123 population <2 years old. Only 11% of patients presented after 2 years of age, and the age at presentation was significantly lower (P < .05) in black African patients. All ethnic groups were affected. In 84% of patients, intussusception occurred at the ileocolic region junction, in 7% it was ileoileal, and in 9% it was colocolic. Colocolic intussusception appeared more common in black African patients, and associated pathologic conditions (polyps and Burkitt's lymphoma) occurred mainly in older children. Surgical intervention was required in 81% of patients and involved resection of gangrenous bowel in 40%. CONCLUSION: Intussusception appears to be a relatively frequent occurrence in children in South Africa. Although the clinical spectrum appears to vary, there is an apparent link to intestinal infection, which requires further investigation. A collaborative approach is required to ascertain the relationship of intussusception to preventable infections and to improve its diagnosis and management.

Atypical antipsychotic (clozapine) self-poisoning in late pregnancy presenting with absent fetal heart rate variability without acidosis and delayed peristalsis in the newborn baby: a case report.

A case of an attempted suicide with atypical antipsychotic (clozapine) in late pregnancy is reported. Toxic effects of clozapine in the mother as well as in the fetus and newborn were observed. It should be remembered as a rare cause of unexplained loss of consciousness in pregnant women, a cause of abnormalities on fetal cardiotocogram as well as a cause of delayed peristalsis in a newborn baby.

The spectrum of anorectal malformations in Africa.

Anorectal malformations (ARM) remain a significant birth defect with geographic variation in incidence, individual phenotypes and regional geographic subtypes. Although early studies indicated a low incidence in Black patients, there is a great paucity of knowledge as to the types, frequency and incidence of ARMs encountered in the African continent and their associated anomalies. Current evidence suggests a significant clinical load. This study set out to evaluate ARM in Southern and other parts of Africa to define the clinical load of ARM. We retrospectively collected data on 1,401 ARM patients from six South African Paediatric Surgical units plus representative samples from five other African countries from West, Central and Southern Africa. Data included ethnic group, age, gender as well as the anatomical pathology, classification and presence or absence of associated anomalies. ARM lesions classified by the Wingspread classification plus an analysis of fistula position was carried out in evaluable cases for purposes of comparison. South African centres reported a higher prevalence of cloacae and vestibular fistulae, whereas rectovaginal, recto prostatic and anorectal malformation without fistula were more prevalent in the Northern African group. 76% of 1,401 patients were ethnically Black African [gender ratio = 2 (vs gender ratio 1.38 overall)] and 49.8% were "low" lesions (Wingspread classification). High or intermediate lesions were mostly males (72%). Anal stenosis was most prevalent in black males and non-Black females. Fistulae were identified in 95% with 682 (52%) being low (perineal/covered anus/vestibular) fistulae. Perineal fistulae had a male predilection (n = 260; 20%), whereas vestibular fistulas (n = 416; 32%) was strikingly frequent in black females (55%). Of the remainder, 15 fistulae were rectovesical (1.2%), 544 recto-urethral or prostatic (42%), 16 recto-vaginal (1.2%). In addition, there were 43 cloacal lesions (3.3%). Isolated rare ARM anomalies included "Pouch" colon (2) and H-type fistula (2). Isolated lesions occurred in 81% but 163 associated anomalies were identified in 114 patients. These included chromosomal lesions (10), genito-urinary anomalies (50), genital (16), cardiac (31), skeletal anomalies (33), gastro-intestinal malformations (28). Other anomalies included CNS anomalies (14), anterior abdominal wall defects (2) and facial (8) abnormalities and neuroblastoma (1). The ARM is not uncommon in Black African populations and constitutes a significant clinical load to surgical practice in Africa. Ethnic differences appear to exist and vestibular fistulae predominate in black females. Cloaca (3.3%) did appear to be more prevalent. Isolated lesions are frequent but the types of associated anomalies appear similar to other series except chromosomal syndromes. This study illustrates the need for more objective data from developing countries to assess geographical differences.

Preoperative angioembolisation for life-threatening haemorrhage from Wilms' tumour: a case report.

Wilms' tumour is one of the most common abdominal tumours of childhood. Severe perirenal bleeding resulting in consumptive coagulopathy and colonic obstruction are rare complications of Wilms' tumour. We present a case report of one patient with these two complications, their successful management with preoperative angioembolisation and emergency nephrectomy, and a review of the relevant literature.

Application of the Malone antegrade continence enema principle in degenerative leiomyopathy.

An 1-year-old boy with degenerative leiomyopathy (DL) presented with a volvulus of the transverse colon. After derotating the volvulus, we constructed a tube colostomy (TC) from the transverse colon. This TC has been used for the past 2 years by the patient for regular deflation of the colon and antegrade colonic enemas (ACE). We present this as a preliminary report of the use of the Malone ACE procedure in a patient with DL and review the relevant literature.

The release of leptin and its effect on hormone release from human pituitary adenomas.

BACKGROUND: Leptin is the protein product of the obese gene, known to play an important role in body energy balance. The leptin receptor exists in numerous isoforms, the long isoform being the major form involved in signal transduction. Leptin expression has recently been demonstrated in the human pituitary, both in normal tissue and in pituitary adenomas. The long isoform of the leptin receptor has also been shown to be present in pituitary adenomas; however, contrasting results have been obtained regarding its expression in the normal human pituitary. AIM: The aim of this study was (i) to investigate the presence and pattern of distribution of leptin mRNA and the long isoform of its receptor mRNA in the normal pituitary and in different types of pituitary adenomas with RT-PCR; (ii) to study leptin secretion from human pituitary tumours in culture and (iii) to assess in vitro pituitary hormone release following stimulation with human leptin. RESULTS: Leptin receptor long isoform expression was detected in 2/4 GH-secreting adenomas, 12/17 non-functioning adenomas, 5/9 ACTH-secreting adenomas, 1/2 prolactinomas, 2/2 FSH-secreting adenomas and 5/5 normal pituitaries. The receptor long isoform did not segregate with any particular tumour type, and varying levels of expression were detected between the tissues studied. Leptin mRNA was detected at a low level of expression in 2/7 GH-secreting adenomas, 9/14 non-functioning adenomas, 2/3 ACTH-secreting adenomas, 1/3 prolactinomas and 1/3 FSH-secreting adenomas. We were unable to detect leptin mRNA in any of the five normal pituitaries removed at autopsy; however, immunostaining of a non-tumorous pituitary adjacent to an adenoma removed at transsphenoidal surgery showed scattered leptin positive cells. Culture of pituitary adenomas showed that 16/47 released leptin into the incubation media. Leptin release did not correlate with tumour type or with any of the other pituitary hormones released. In vitro leptin stimulation of pituitary tumours caused stimulation of FSH and alpha-subunit secretion from a non-functioning adenoma and TSH secretion from a somatotroph adenoma. CONCLUSION: We conclude that not only is leptin stored within the pituitary, but it may also be released from pituitary cells and modulate other pituitary hormone secretion. Pituitary leptin may therefore be a novel paracrine regulator of pituitary function.

Leptin in pituitary adenomas--a novel paracrine regulatory system.

A growing number of physiological and pathophysiological processes have been shown to be influenced by leptin apart from its first recognised role as a modulator of hypothalamic appetite and weight control centers. We investigated the presence and pattern of distribution of leptin mRNA and the mRNA of the long isoform of the leptin receptor in the normal pituitary and in different types of pituitary adenomas. We also studied leptin secretion from human pituitary tumors in culture, and the in vitro pituitary hormone release following stimulation with human leptin. Leptin mRNA expression was detected at a low level of expression in 50% of tumors but in none of the normal pituitaries. By immunohistochemistry, leptin was present in occasional scattered cells in the normal pituitary and in pituitary tumors. The leptin receptor long isoform was detected in the majority (65%) of pituitary tumors and in all normal pituitaries. It did not segregate with any particular tumor type, and varying levels of expression were detected between the tissues studied. 34% of pituitary adenomas showed leptin release into the incubation media during in vitro culture. Leptin mRNA, the mRNA of the long isoform of the receptor, or in vitro leptin release, did not correlate with tumor type or with any of the other pituitary hormones released. In vitro leptin stimulation of pituitary tumors caused stimulation of FSH and a-subunit secretion from a non-functioning adenoma and TSH secretion from a somatotroph adenoma. As the co-localisation of ACTH and leptin in corticotroph cells was previously suggested, we investigated whether in vivo ACTH release is accompanied by a simultaneous plasma leptin level rise (i) in peripheral plasma samples after food intake-induced ACTH rise in healthy obese and nonobese individuals and (ii) in petrosal sinus samples after CRH injection in Cushing's disease patients. Our data suggest that a rise in ACTH levels is not accompanied by detectable rise in leptin levels in peripheral and in petrosal sinus blood samples. In summary, leptin is synthesized and stored within the pituitary and may modulate other pituitary hormone secretion, although probably it does not contribute to plasma leptin level changes. Pituitary leptin may therefore be a novel paracrine regulator of pituitary function.

Hypothyroldism in a neonate following excision of a cervical teratoma.

Hypothyroidism developed in a neonate following the excision of a large cervical teratoma. This finding supports the observation that cervical teratomas commonly arise from thyroid tissue. Thyroid function tests should be performed routinely in all patients in whom identifiable residual thyroid tissue is not demonstrated at the conclusion of the operation.

Familial aplasia cutis congenita.

Two siblings with extensive aplasia cutis congenita of the extremities are described. These lesions healed spontaneously and in the older sibling at four years follow-up there was minimal scar tissue at the affected sites.

Synthesis, characterization, cytotoxic, and DNA binding studies of some platinum (II) complexes of 1,2-diamine and alpha-diimine with 2-pyridinecarboxylate anion.

Seven new water-soluble cationic complexes of general formula [Pt(2-pyc)(N-N)]+ (where N-N is 2NH3, ethylenediamine (en), 1,2-diaminopropane (1,2-dap), 1,3-diaminopropane (1,3-dap), (+/-) trans-1,2-diaminocyclohaxane (dach), 2,2'-dipyridylamine (dpa) or 1,10-phenanthroline (phen), and 2-pyridinecarboxylate anion) have been prepared. These complexes have been characterized by conductance measurements, and by ultraviolet-visible, infrared (IR), and 1H nuclear magnetic resonance (NMR) spectroscopy. The COSY (correlated spectroscopy) spectra of [Pt(2-pyc)(dpa)]+ and [Pt(2-pys)(dpa)]+ further support the structures of the above complexes with three nitrogen and one oxygen donor atoms in the first coordination sphere of platinum(II) with 1,2-diamine or alpha-diimine and 2-pyridinecarboxylate anion behaving as bidentate ligands. One of the compounds, [Pt(2-pyc)(dpa)]Cl, also shows a birefringence property in water. These compounds inhibit the growth of P388 lymphocytic leukemia cells. [Pt(2-pyc)(dpa)]+ shows I.D.50 value comparable to cisplatin. However, six other complexes show higher I.D.50 values than cisplatin. In addition, the inhibition studies also suggest that their target is DNA. Therefore, the interactions of four of the above complexes with calf thymus DNA have been studied by ultraviolet and fluorescence spectral methods. These studies suggest that [Pt(2-pyc)(NH3)2]+ and [Pt(2-pyc)(1,2-dap)+ bind to DNA by noncovalent interactions. On the other hand, [Pt(2-pyc)(dpa)]+ and [Pt(2-pyc)(phen)]+ bind to DNA by covalent monofunctional binding. The latter two complexes have also been interacted with PUC19 DNA. The gel electrophoresis studies of these interactions suggest that these complexes bind to DNA, and this binding leads to a conformational change in DNA.

Selenium (Se) cytotoxicity in drug sensitive and drug resistant murine tumour.

Selenium is known to inhibit growth rate of neoplastic cells. We have investigated the role of selenium (Se) in resensitization of the adriamycin (ADR) resistant murine P388/ADR cells to the action of ADR. The experiments were performed in the ADR sensitive parental P388 murine leukemia (P388/S) and its subline P388/ADR, resistant to ADR, developed in our laboratory. The effect of Se was observed to be dose dependent i.e. Se at a concentration of 5 x 10(-8)M resulted in potentiation of DNA biosynthesis whereas 5 x 10(-6)M and 5 x 10(-5)M Se resulted in inhibition of DNA-biosynthesis in P388/S cells. Along with ADR there was a further increase in inhibition of DNA biosynthesis. In P388/ADR cells, Se at 5 x 10(-6)M and 5 x 10(-8)M concentration resulted in inhibition of DNA biosynthesis, which increased further when combined with ADR indicating resensitization of these cells to the action of ADR. The inhibition was observed to be partially irreversible. These results were further confirmed in the in vivo and in vitro bioassays where the Se and Se+ ADR treatments resulted in increased lifespan of tumor bearing mice.

Effect of pentoxifylline, a multidrug resistance reversal agent, on haemopoietic stem cell homing.

This paper investigates the mechanism of mouse haemopoietic stem cell homing into the cytoskeleton depolymerizing agent Pentoxifylline was used, and shown to inhibit stem cell homing. The inhibition was reversible after 6 hours. The results obtained suggest that the haemopoietic stem cell homing receptor is anchored to cytoskeletal support intracellularly.

In vitro effects of pentoxifylline and doxorubicin on cell survival and DNA damage in sensitive and MDR-P388 leukemia cells.

The utility of chemosensitizers to improve efficacy of chemotherapy is now gaining importance. This report investigated whether an active hemorheological agent, pentoxifylline (PTX), can circumvent drug resistance in parental (P388/S) and multidrug resistant (P388/DOX) P388 leukemia cells. For detection of doxorubicin (DOX) resistance and reversal of this resistance by PTX, the incorporation of nucleic acid precursor was measured after addition of DOX and PTX, respectively. The effect of PTX on the induction of DNA strand breaks by DOX was also examined. Increased fragmentation of DNA was illustrated in P388/DOX leukemia cells exposed to the combination of DOX and PTX. The most prominent feature of the multidrug-resistant cell is the reduced accumulation of the drug intracellularly. P388/DOX cells showed less accumulation of DOX in the cell as compared to that of the parental cell line. Further studies demonstrated that PTX significantly enhanced the intracellular accumulation of DOX in both the cell lines. These studies warrant the use of PTX as an adjuvant in cancer chemotherapy.

Some potential antitumor 2,2'-dipyridylamine Pt(II)/Pd(II) complexes with amino acids: their synthesis, spectroscopy, DNA binding, and cytotoxic studies.

Four new palladium(II) and platinum(II) complexes of formula [M(dipy)(AA)]+ (where dipy is 2,2'-dipyridylamine, AA is an anion of glycine or L-alanine, and M is Pd(II) or Pt(II)) have been synthesized and characterized with amino acids binding as bidentate ligands. These complexes are 1:1 electrolyte in conductivity water. Of the above four complexes, the two L-alanine complexes show ID50 values against P388 lymphocytic leukemia cells lower than cis-diamminedichloroplatinum(II), whereas the two glycine complexes show ID50 values higher than cisplatin. The interaction of calf thymus DNA with the above complexes shows significant spectral changes in the presence of [Pt(dipy)(gly)]Cl, [Pd(dipy)(ala)]Cl, and [Pt(dipy)(ala)]Cl and the mode of binding between these complexes and DNA seems to be noncovalent.

Sensitization of P388 murine leukemia cells to epirubicin cytotoxicity by reserpine.

Reserpine, the crystalline active substance isolated from the Rauvolfia plant, produces a characteristic vasodepressor effect in hypertensive patients. Apart from its antihypertensive property, reserpine also possesses transquillising and vasodepressor action, hence it is employed as supportive therapy in the treatment of cardiac disorders. Doxorubicin is a potent anticancer agent, the use of which is limited by its cumulative dose-dependent cardiotoxicity. Epirubicin is a derivative of doxorubicin having more favourable therapeutic index than doxorubicin and possessing less hematologic and cardiac toxicity at comparable doses. The data presented in this paper show the effect of reserpine as a chemosensitizer, when used in combination with epirubicin on P388 murine leukemia cells sensitive (P388/S) and resistant to doxorubicin (P388/DOX) cells. Inhibition of 3H-TdR incorporation into DNA was used as an index of the cytotoxic effects of drug when used alone or in combination. The combination of reserpine (1 microM) and epirubicin (1.7, 8.6 and 17.2 microM) indicated a significant enhancement in the DNA biosynthesis inhibition in P388/S and P388/DOX cell lines. The most prominent feature of the multidrug-resistant cell is the reduced accumulation of the drug intracellularly. P388/DOX cells showed less accumulation of epirubicin in the cell as compared to that of the parental cell line. Further studies demonstrated that reserpine significantly enhanced the intracellular accumulation of epirubicin in both the cell lines. The nature of DNA damage caused by the combination of reserpine and epirubicin was irreversible when studied in P388/DOX cell line. The combination of reserpine (5mg/kg) and epirubicin (1mg/kg) significantly potentiated the antitumor activity of epirubicin in P388/DOX tumor bearing mice. These studies suggest that reserpine can be used as an adjuvant in the cancer chemotherapy to potentiate the antiproliferative activity of anticancer drugs.

Cytotoxicity and DNA binding studies of several platinum (II) and palladium (II) complexes of the 2,2'-bipyridine and an anion of 2-pyridinecarboxylic/2-pyrazinecarboxylic acid.

Four water soluble complexes of the type [M(bpy)(a-x)]NO3, where M is Pd(II) or Pt(II), bpy is 2,2-bipyridine, and a-x is anion of 2-pyridinecarboxylic acid or 2-pyrazinecarboxylic acid, have been found to bind calf thymus DNA, possibly through hydrogen binding. [M(bpy)(2-py)]NO3 complexes (2-py is an anion of 2-pyridinecarboxylic acid) show I.D.50 values smaller than cisplatin whereas [M(bpy)(2-pyz)]NO3 complexes (2-pyz is an anion of 2-pyrazinecarboxylic acid) show I.D.50 values larger than cisplatin against P388 cancer cells.