Peptides for diagnosis and treatment of colorectal cancer

Colorectal cancer (CRC) is a major health concern worldwide, as it is the third most frequently diagnosed cancer and the second leading cause of cancer-related death. There are a number of treatment options for CRC, however many of them are disappointing. Therefore, significant efforts are directed towards the development of new biological therapies with improved efficacy. The use of peptides in CRC treatment holds promise as emerging novel anti-cancer agents. Targeted therapy based on the use of peptides that can directly target tumor cells without affecting normal cells is evolving as an alternative strategy to conventional therapies and particularly, chemotherapy. The main advantages of peptides are their relatively easy and rapid synthesis process, and the vast possibilities for chemical modifications that can be exploited for novel peptide design and improved delivery. Peptides can be utilized directly as cytotoxic agents or indirectly as they can act as carriers of cytotoxic agents, drugs, or radioisotopes by specifically targeting tumor cells. They can also be used for diagnostic purposes. Current research focuses on developing peptides that can serve as tumor targeting moieties, permeabilize membranes to induce cytotoxicy, radiolabeled peptides, and peptide vaccines. In addition, improving targeting to tumors, reducing side effects, due to non-specific toxicity, and unraveling the pharmacokinetic characteristics of potential peptides, for either therapeutic or diagnostic use, are also subjects of intensive investigation. This review provides a brief overview on the role of peptides in CRC diagnosis and therapy that are currently being investigated, and their potential applications in the clinical setting.

Short communication: The use of a perinatal internet consultation forum in Israel*

To analyse the use of a free, public, perinatal internet consultation service, 2000 consultations provided by university hospital staff were evaluated over 30 months. Ninety five percent of the questioners were women, and 62% of them were primiparous. The average response rate was 2.3 audience responses per question. Fifty-two percent of the consultations were related to labour and delivery, 23% were related to pregnancy complications, 16% were related to prenatal diagnosis, and 7% were related to the puerperium period. We conclude that medical consultation forums provide an additional way of delivering inexpensive, accessible, fast, and convenient healthcare services.

The tumor suppressor neurofibromin confers sensitivity to apoptosis by Ras-dependent and Ras-independent pathways

Neurofibromatosis type 1 (NF1) is characterized by a high incidence of benign and malignant tumors attributed to loss of function of Nf1, which encodes neurofibromin, a tumor suppressor with Ras-GAP activity. Neurofibromin deficiency typically causes chronic activation of Ras, considered the major contributor to manifestation of NF1. Resistance to radio- and chemotherapy are typical of NF1-associated tumors, but the underlying mechanism is unknown. Here, we investigated interrelationships between neurofibromin expression, Ras activity, and sensitivity to apoptosis. Neurofibromin-deficient mouse embryonic fibroblasts (MEFs) and human NF1 tumor cells were more resistant than neurofibromin-expressing cells to apoptosis. Moreover, Nf1(-/-), Nf1(+/-), and Nf1(+/+) MEFs exhibited gene-dosage-related resistance to apoptosis. Resistance of the Nf1-deficient cells was mediated by two survival pathways: a Ras-dependent pathway, and a Ras-independent pathway promoted by the lack of an NF1-GRD-independent proapoptotic action of neurofibromin. Therefore, besides its Ras-dependent growth inhibition, neurofibromin can exert tumor suppression via a proapoptotic effect.

Suppression of NF-kappaB activation by infection with Toxoplasma gondii

The interaction of host cells with microbial products or their invasion by pathogens frequently results in activation of the NF-kappaB family of transcription factors. The studies presented here reveal that in vivo, infection with Toxoplasma gondii results in the activation of NF-kappaB. To determine whether host cells could activate NF-kappaB in response to invasion by T. gondii, Western blots, immunofluorescence, and electrophoretic mobility shift assays were used to assess the response of host cells to infection. In these studies, infection of macrophages or fibroblasts with T. gondii did not result in the activation of NF-kappaB. In addition, the ability of lipopolysaccharide to activate NF-kappaB was impaired in cultures of macrophages infected with T. gondii. Together, these data demonstrate that invasion of cells by T. gondii does not lead to the activation of NF-kappaB and suggest that the parasite may actively interfere with the pathways that lead to NF-kappaB activation.

The effect of storage on the expression of platelet membrane phosphatidylserine and the subsequent impacton the coagulant function of stored platelets

BACKGROUND

Platelet concentrates (PCs) derived from whole blood and stored under standard blood bank conditions undergo changes that are referred to as the platelet storage lesion. This study assesses the effect of PC preparation and storage on the distribution of phosphatidylserine (PS) in the platelet membrane and the effect that this distribution may have on the thrombogenic potential of stored PCs.

STUDY DESIGN AND METHODS

Fresh platelets and PCs donated by healthy donors were obtained. PCs derived from platelet-rich plasma were studied on Day 1, Day 3, and Day 6 of storage under blood bank conditions.

RESULTS

Platelet aggregation after exposure to the platelet agonists ADP and epinephrine singly declined progressively, but, when ADP and epinephrine in combination and collagen and thrombin in combination were used as agonists, the decline in platelet aggregation was less marked. PS expression as measured by Annexin V binding (mean and SD) was 2.02 +/- 0.93 percent in fresh platelet samples and increased to 5.39 +/- 4.2 percent on Day 1, 22. 1 +/- 7.1 percent on Day 3, and 39.5 +/- 12.1 percent on Day 6. Platelet prothrombinase activity (mean +/- SD) as measured by thrombin generation increased from 1.49 +/- 0.7 micro per mL in fresh platelet samples to 3.68 +/- 1.1 micro per mL in Day 1 platelets (p<0.001), 5.15 +/- 2.5 micro per mL in Day 3 platelets (p<0.001), and 4.65 +/- 2.48 micro per mL in Day 6 platelets (p<0. 001).

CONCLUSION

These results show that PS expression increases after preparation of PCs from platelet-rich plasma and rises progressively during platelet storage under blood bank conditions. Furthermore, the greater PS expression is associated with increased platelet- dependent thrombin-generating capacity.

Interband scattering and the "Metallic Phase" of two-dimensional holes in GaAs /AlGaAs

The "metallic" characteristics of high density holes in GaAs/AlGaAs heterostructures are attributed to inelastic scattering between the two split heavy hole bands. Landau fan diagrams and weak field magnetoresistance are employed to measure the interband scattering rate. The inelastic rate is found to depend on temperature with an activation energy similar to that characterizing the longitudinal resistance. It is argued that acoustic plasmon mediated Coulomb scattering might be responsible for the Arrhenius dependence on temperature. The absence of standard Coulomb scattering characterized by a power-law dependence upon temperature is pointed out.

Anomalous behavior of superconducting-normal mesoscopic structures near T(c)

We observe a maximum in the conductance of Al/n-GaAs junctions at temperatures 20 mK lower than the superconducting transition temperature (T(c)). This is the first observation of a peak in the conductance near the superconducting transition in superconducting-normal (S/N) junctions. To accommodate this effect we calculate the full temperature dependence of the conductance of these structures, invoking quasiclassical Green's functions in the diffusive limit. In addition to the well-known low-temperature peak at temperatures on the order of the Thouless energy, we find a maximum near T(c). This peak has the same origin as the subgap conductance observed in S/N junctions at low temperatures.

Induced second trimester abortion by extra-amniotic prostaglandin infusion in patients with a cesarean scar: is it safe?

BACKGROUND

One result of the advancement in prenatal diagnosis is an increase in the need for second trimester pregnancy terminations. Extra-amniotic infusion of prostaglandins is a common technique used for such pregnancy termination. Since prostaglandins cause strong uterine contractions, many practitioners are hesitant to use this technique on women with a uterine scar. In this study we tried to evaluate the effectiveness and safety of the technique for women with a previous uterine scar.

METHODS

This retrospective study included all women with a complete medical record who underwent a second trimester pregnancy termination at our institution by extra amniotic prostaglandin E2, during a 6 year period. The study group included all women with a previous uterine scar. The group of women without such a scar served as the control group.

RESULTS

Three hundred and forty women had their pregnancy terminated, but only in 282 cases was the medical information complete (research population). The study group (35 women) characteristics were similar to those of the control group (247 women). We found no difference in the abortion interval, the need to use an additional method, the need for curettage and in bleeding complication between the two groups. There was no case of uterine rupture. The group of women with multiple uterine scars was too small for analysis.

CONCLUSIONS

Our results suggest that extra amniotic prostaglandin infusion is an effective and safe technique in women with a uterine scar.

Effect of epidural analgesia on duration and outcome of induced labor

OBJECTIVE

To evaluate the effect of epidural block on the duration of labor and maternal and fetal outcome in induced-labor patients.

METHOD

210 women admitted for induction of labor at a level III university hospital, during the year 1991, were studied. Of these, 112 were given an epidural block and 98 served as controls. Outcome measures studied were: induction time and time in labor, c-section and instrumental delivery rates, intra-partum and post-partum complications, and Apgar scores at 1 and 5 min.

RESULT

Multiple regression analysis revealed that epidural analgesia, before and after adjustment for confounding factors, significantly prolonged labor time (P < 0.0001) and was associated with an increase in instrumental delivery rates (P < 0.04). A significant reduction in intra-partum complication rate (FHR changes, meconium) was observed (OR = 0.32; P < 0.03), while c-section rate and Apgar scores were not found to be influenced by epidural analgesia.

CONCLUSION

Epidural anesthesia, significantly prolongs labor time in induced patients. While instrumental delivery was more prevalent in these parturients, c-section rate was not increased and intra-partum complications were significantly reduced in these patients.

The role of uterine straightening by passive bladder distension before embryo transfer in IVF cycles

PURPOSE

The present study investigated the effect of bladder distension on in vitro fertilization and embryo transfer (IVF-ET) results.

METHODS

The study comprised 796 patients after successful transvaginal oocyte pickup and IVF, who, on the basis of bladder filling for ET, were divided into two groups. In group E, 385 patients underwent ET with an empty bladder, and in group F, 411 patients underwent ET with a full bladder.

RESULTS

Sixty-four pregnancies were achieved in group E (16.6%), compared to 110 pregnancies in group F (26.8%, P = 0.006). A similar pregnancy loss rate was observed in both groups, 13 in group E (20.3%) and 29 in group F (26.4%; P = NS).

CONCLUSIONS

A significantly higher pregnancy rate was achieved with routine bladder distension before ET, probably attributable to the smooth and easy insertion of the ET catheter.

Sarin-induced neuropathology in rats

Sarin, a highly toxic cholinesterase (ChE) inhibitor, administered at near 1 LD50 dose causes severe signs of toxic cholinergic hyperactivity in both the peripheral and central nervous systems (CNS). The present study evaluated acute and long-term neuropathology following exposure to a single LD50 dose of sarin and compared it to lesions caused by equipotent doses of soman described previously. Rats surviving 1 LD50 dose of sarin (95 micrograms/kg; IM), were sacrificed at different time intervals post exposure (4 h-90 days) and their brains were taken for histological and morphometric study. Lesions of varying degrees of severity were found in about 70% of the animals, mainly in the hippocampus, piriform cortex, and thalamus. The damage was exacerbated with time and at three months post exposure, it extended to regions which were not initially affected. Morphometric analysis revealed a significant decline in the area of CA1 and CA3 hippocampal cells as well as in the number of CA1 cells. The neuropathological findings, although generally similar to those described following 1 LD50 soman, differed in some features, unique to each compound, for example, frontal cortex damage was specific to soman poisoning. It is concluded that sarin has a potent acute and long-term central neurotoxicity, which must be considered in the design of therapeutic regimes.

Dose-dependent effect of nitric oxide synthase inhibition following transient forebrain ischemia in gerbils

The extensive research concerning the interaction between nitric oxide (NO) and ischemic brain tissue has yielded contradictory results. The present study was designed to explore the effect of gradual inhibition of NO production on brain ischemia. Gerbils were administered (i.p.) either saline (control-ischemia), or 5, 10, 25 or 50 mg/kg of NG-nitro-L-arginine (NARG), a specific inhibitor of NO synthase (NOS), and 4 h later were subjected to 5 min of forebrain ischemia. A group receiving 50 mg/kg NARG with sham operation served as a second control (control-NARG) group. Body weights and spontaneous activity were monitored daily until day 6, when the gerbils were sacrificed and their brains processed for histologic-morphometric evaluation. All ischemia groups displayed significant decreases in body weights starting on day 1, as compared to control-NARG (non-ischemic) gerbils. At 24 h post-ischemia spontaneous activity was increased in all ischemia groups in a dose-dependent manner, reaching a peak at 25 mg/kg. Typical ischemia-induced neuronal cell degeneration was observed at the hippocampal CA1 layer in control-ischemia and in each of the dose-groups of 10 mg/kg NARG and above. The 5 mg/kg group displayed damage which was not different from control-NARG, and was milder (P < 0.01) than control-ischemia gerbils and each of the other dose-groups. It is suggested that during ischemia, NO activates a series of processes which are beneficial to brain tissue, whereas an excess amount of NO causes neurotoxic effects.(ABSTRACT TRUNCATED AT 250 WORDS)

NG-nitro-L-arginine enhances neuronal death following transient forebrain ischemia in gerbils

Experiments were performed with Mongolian gerbils to study the effect of the specific nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine (L-NNA) on ischemic brain damage induced by 5 min bilateral carotid occlusion. A single i.p. injection of L-NNA did not result in any neuronal loss in the central nervous system. In animals undergoing ischemia, a selective destruction of hippocampal CA1 cells was observed whereas pretreatment with 50 mg/kg L-NNA 4 h before administration of ischemia produced significantly more extensive cell damage in the hippocampus and other brain regions. These findings demonstrate that in this model inhibition of nitric oxide generation augments ischemia-induced neuronal cell injury in the brain.

Thickening of the adrenal zona glomerulosa in dogs induced by oxodipine, a calcium channel blocker

Subchronic effects of oxodipine, a calcium channel blocker affecting the adrenal gland of the dog, are described. Thirteen wk of treatment at a high dose (24 mg/kg/day) of oxodipine resulted in drug-induced thickening of the zona glomerulosa and increased stimulation of its secretory activity. It is postulated that subchronic administration of oxodipine at this dosage resulted in a decrease in blood pressure, with uninterrupted stimulation of the adrenal zona glomerulosa to release aldosterone, causing an increase in the width of this portion of the gland involving cellular hyperplasia. Support for this indirect effect is found in the increased presence of renin granules in the juxtaglomerular apparatus.

Percutaneous transluminal angioplasty of proximal subclavian artery stenosis after left internal mammary to left anterior descending artery bypass surgery

A patient is described who underwent percutaneous transluminal angioplasty, through a brachial approach, of a high grade stenosis at the proximal portion of the left subclavian artery 1.5 years after coronary artery bypass grafting including left internal mammary to left anterior descending artery anastomosis. Symptoms of class IV angina, vertebrobasilar insufficiency and occupational arm claudication that developed after bypass surgery were promptly relieved after balloon dilation. Percutaneous transluminal angioplasty of the subclavian artery can be performed safely and provides an alternative to carotid-subclavian or axillary-axillary bypass surgery for treatment of internal mammary artery graft malfunction.

A goldfish model for evaluation of the neurotoxicity of omega-conotoxin GVI A and screening of monoclonal antibodies

The neurotoxicity of omega-conotoxin (omega-CgTx), a potent neuronal voltage-sensitive calcium channel blocker, was measured using a new bioassay. omega-CgTx was administered intraperitoneally (ip) to goldfish weighing approximately 1.6 g, and dose-related changes were observed over a 2-hr period. omega-CgTx induced time- and dose-dependent abnormal swimming behavior (ASB) and mortality. The antitoxin activity of the antibodies was investigated in vivo by either (1) preincubation of the antibody with omega-CgTx at 4 degrees C overnight, or (2) pretreatment with antibody, 30 min before omega-CgTx injection in a 10:1 antibody/omega-CgTx molar ratio. The LD50 dose of omega-CgTx in goldfish was 5 nmol/kg ip, and preincubation of monoclonal antibody (50 nmol/kg ip) with omega-CgTx (5 nmol/kg ip) significantly (p less than 0.05) reduced mortality, ASB, and toxicity time. The antitoxin activity of the monoclonal antibodies evidenced in the goldfish bioassay was further tested in the conscious rat. In the rat, the increases in mean arterial pressure and heart rate induced by omega-CgTx (0.03 nmol/rat icv) were significantly (p less than 0.02 and p less than 0.01, respectively) attenuated by preincubation of the toxin with the antibody (0.3 nmol/rat). We conclude that the goldfish bioassay provides a simple, accurate, and inexpensive in vivo model for the study of the toxicity of omega-CgTx.

Butyrylcholinesterase and acetylcholinesterase prophylaxis against soman poisoning in mice

Human butyrylcholinesterase (BChE, EC 3.1.1.8) or acetylcholinesterase (AChE, EC 3.1.1.7) from fetal bovine serum (FBS), administered i.v. in mice, sequestered at approximately 1:1 stoichiometry the highly toxic anti-ChE organophosphate, 1,2,2-trimethylpropyl methyl-fluorophosphonate (soman). A quantitative linear correlation was demonstrated between blood-ChE levels and the protection conferred by exogeneously administered ChE. Results presented here demonstrate that either human BChE or FBS-AChE is an effective prophylactic measure sufficient to protect mice from multiple LD50S of soman without the administration of post-treatment supportive drugs.