Synthetic peptide derived from α‐fetoprotein inhibits growth of human breast cancer: investigation of the pharmacophore and synthesis optimization

Abstract: A synthetic peptide that inhibits the growth of estrogen receptor positive (ER+) human breast cancers, growing as xenografts in mice, has been reported. The cyclic 9‐mer peptide, cyclo[EMTOVNOGQ], is derived from α‐fetoprotein (AFP), a safe, naturally occurring human protein produced during pregnancy, which itself has anti‐estrogenic and anti‐breast cancer activity. To determine the pharmacophore of the peptide, a series of analogs was prepared using solid‐phase peptide synthesis. Analogs were screened in a 1‐day bioassay, which assessed their ability to inhibit the estrogen‐stimulated growth of uterus in immature mice. Deletion of glutamic acid, Glu1, abolished activity of the peptide, but glutamine (Gln) or asparagine (Asn) could be substituted for Glu1 without loss of activity. Methionine (Met2) was replaced with lysine (Lys) or tyrosine (Tyr) with retention of activity. Substitution of Lys for Met2 in the cyclic molecule resulted in a compound with activity comparable with the Met2‐containing cyclic molecule, but with a greater than twofold increase in purity and corresponding increase in yield. This Lys analog demonstrated anti‐breast cancer activity equivalent to that of the original Met‐containing peptide. Therefore, Met2 is not essential for biologic activity and substitution of Lys is synthetically advantageous. Threonine (Thr3) is a nonessential site, and can be substituted with serine (Ser), valine (Val), or alanine (Ala) without significant loss of activity. Hydroxyproline (Hyp), substituted in place of the naturally occurring prolines (Pro4, Pro7), allowed retention of activity and increased stability of the peptide during storage. Replacement of the first Pro (Pro4) with Ser maintains the activity of the peptide, but substitution of Ser for the second Pro (Pro7) abolishes the activity of the peptide. This suggests that the imino acid at residue 7 is important for conformation of the peptide, and the backbone atoms are part of the pharmacophore, but Pro4 is not essential. Valine (Val5) can be substituted only with branched‐chain amino acids (isoleucine, leucine or Thr); replacement by d ‐valine or Ala resulted in loss of biologic activity. Thus, for this site, the bulky branched side chain is essential. Asparagine (Asn6) is essential for activity. Substitution with Gln or aspartic acid (Asp), resulted in reduction of biologic activity. Removal of glycine (Gly8) resulted in a loss of activity but nonconservative substitutions can be made at this site without a loss of activity indicating that it is not part of the pharmacophore. Cyclization of the peptide is facilitated by addition of Gln9, but this residue does not occur in AFP nor is it necessary for activity. Gln9 can be replaced with Asn, resulting in a molecule with similar activity. These data indicate that the pharmacophore of the peptide includes side chains of Val5 and Asn6 and backbone atoms contributed by Thr3, Val5, Asn6, Hyp7 and Gly8. Met2 and Gln9 can be modified or replaced. Glu1 can be replaced with charged amino acids, and is not likely to be part of the binding site of the peptide. The results of this study provide information that will be helpful in the rational modification of cyclo[EMTOVNOGQ] to yield peptide analogs and peptidomimetics with advantages in synthesis, pharmacologic properties, and biologic activity.     

Laryngeal melanosis

We describ a case iaryngcul melanosis in a 62 year old male. the pigmentation was visible on gross examination during laryngoscopy ana histologicatly a single foci showing changes of carcinoma in situ was identified. The biopsy tissue, however did not reveal any frank changes of malignancy.     

Nonoperative management of bile leaks following liver transplantation

The biliary anastomosis has been called ‘the Achilles heel’ of liver transplantation (Rabkin JM, Orloff SL, Reed MH . Transplantation 1998: 65 [2]: 193; Davidson BR, Rai R, Kurzawinski TR . Br J Surg 1999: 86 [4]: 447). Biliary complications after liver transplantation reportedly occur at an incidence of 20–30%, 10–15% as bile leaks. The management of bile leaks, especially early bile leaks, is controversial. In the present study, we report our experience with the management of bile leaks after liver transplantation.
In this retrospective study, we reviewed 85 liver transplants over a 3‐yr period. In 79, the biliary anastomosis was choledochocholedochostomy (CDCD) over a small‐caliber T‐tube, while choledochojejunostomy (CDJ) was used in 7. Over a mean follow up period of 13.5 months (median 10 months), 10 patients (12%) experienced a clinically significant bile leak within the first 3 months after liver transplantation.
The early leaks, occurring within 1 month of transplant, were successfully managed by observation (Davidson BR, Rai R, Kurzawinski TR . Br J Surg 1999: 86 [4]: 447) or endoscopic retrograde cholangiopancreatography (ERCP) and the placement of a biliary stent for a duration of 6–12 wk (Randall HB, Wachs ME, Somberg KA . Transplantation 1996: 61 [2]: 258). One of these resulted from accidental dislodgement of the T‐tube on postoperative day 1; one resulted from necrosis at the CDCD anastomosis and required CDJ; the remaining four resulted from leaks along the T‐tube track.
One of the late leaks occurred following the planned removal of the T‐tube at 3 months after liver transplantation; the other two were leaks along the T‐tube track. All were successfully treated by ERCP and stent placement, though in one case, ERCP was initially unsuccessful because of the inability to advance a guidewire, necessitating a fluoroscopically aided guide wire placement during a mini laparotomy. ERCP was then successfully performed with the placement of a stent. Table 1 Conclusions: Our experience indicates that most bile leaks after liver transplantation, including early leaks, can be successfully managed nonoperatively. Most will require intervention, but ERCP and stent placement are usually sufficient.

The pectoralis major myocutaneous flap in head and neck reconstruction

The pectoralis major myocutaneous flap (PMMC flap) represents a landmark in the development of head and neck reconstructive surgery. After Stephan Ariyan first described its use for head and neck reconstruction in 1979, it has become tremendously popular and has revolutionised head and neck cancer surgery. Here, we present our initial experience with fourteen PMMC flaps in head and neck reconstruction. In most of the instances it was used for oral or oropharyngeal reconstruction. It was used for five other reconstructive tasks as well. Wound infection was the most common complication. There was no case of total flap loss. It has proven to be a reliable method of reconstuction in the head and neck.     

Estimation of nonheme-iron bioavailability from meal composition

BACKGROUND: Considerable data are available on the individual effects of dietary factors on nonheme-iron absorption, but their combined effect when they are present in the same meal is not known. OBJECTIVE: Our objective was to predict the bioavailability of iron from complex meals that are consumed commonly in the United States on the basis of the contents of factors that are known to promote or inhibit food iron absorption. DESIGN: Radioisotopic measurements of nonheme-iron absorption from 25 meals were made in 86 volunteer subjects by using extrinsic radioiron labeling. The meal contents of nonheme iron, calcium, ascorbic acid, polyphenols, and phytic acid were determined by biochemical analysis; energy and protein contents were estimated from food-composition tables. Animal tissue content was based on weight or was obtained from the manufacturer. RESULTS: After adjusting iron absorption for differences in iron status, the significant biochemical predictors of iron absorption as determined by multiple regression analysis were the contents of animal tissue (P = 0.0001), phytic acid (P = 0.0001), and ascorbic acid (P = 0. 0441). Collectively, these 3 variables accounted for 16.4% of the variation in absorption. On the basis of the multiple regression analysis, we developed the following equation to estimate iron absorption: Ln absorption, % (adjusted to serum ferritin concentration of 30 microg/L) = 1.9786 + (0.0123 x animal tissue in g) - (0.0034 x phytic acid in mg) + (0.0065 x ascorbic acid in mg). CONCLUSION: For the 25 meals evaluated, only the contents of animal tissue, phytic acid, and ascorbic acid were useful for estimating nonheme-iron absorption.     

Interactive suppression of aberrant crypt foci induced by azoxymethane in rat colon by phytic acid and green tea

Several epidemiological studies point to a strong correlation between nutrient composition of the diet and cancer of the colon. Phytic acid, present in grains, has been credited with reducing the risk of cancer of the colon. A number of reports are available indicating the benefits of green tea consumption in reducing the risk of stomach, lung and skin cancer, but little data are available on the effect of green tea in reducing the risk of colon cancer. Also, there are no studies on the combined effect of these compounds on colon tumorigenesis. Thus the primary objective of this investigation was to elucidate the combined effects of green tea and phytic acid on colonic preneoplastic lesions and the Phase II enzyme glutathione S-transferase. Fisher 344 male weanling rats were divided into nine groups of 15 rats each and fed the experimental diet for 13 weeks. Rats received two s.c. injections of azoxymethane in saline at 16 mg/kg body wt at 7 and 8 weeks of age. Rats received three levels (0, 1 and 2%) of phytic acid with three levels (0, 1 and 2%) of green tea within each phytic acid level in a 3 x 3 factorial experiment. Results indicate that while green tea had a marginal effect (P < 0.14), phytic acid significantly reduced the incidence of aberrant crypt foci (P < 0.008). The interaction between green tea and phytic acid was significant (P < 0.029 for distal and < 0.0168 for entire colon) and positive, pointing to a synergistic effect of green tea and phytic acid.      

Colorectal cancer screening attitudes and practices in the general population: a risk-adjusted survey.

OBJECTIVES: To characterize self-reported colorectal cancer (CRC) screening behavior, and to identify characteristics of CRC screening practices, stratified by risk. METHODS: Using random-digit-dial methodology, we conducted telephone surveys in US adults 50 years of age and older. Respondents provided data on utilization of CRC screening tests; demographic characteristics; and awareness, concerns, attitudes and beliefs about the tests, CRC, and health care. On the basis of available guidelines, three definitions of adequate screening were considered. RESULTS: Among persons reporting having ever had a CRC screening exam, the exam was more likely to have been a fecal occult blood test than a radiologic or endoscopic exam (p < .0001). Subjects at increased CRC risk were more likely to have met the screening criteria (p < .001) compared with average-risk subjects. Receipt of information or advice about cancer screening tests, male gender, and concern about managed care were positively associated with adequate screening. Smoking, low health self-monitoring, and an average risk for CRC reduced the probability of CRC screening. CONCLUSIONS: Lack of awareness about screening remains common, regardless of CRC risk. Providing information and advice about cancer screening may be the single most important tool available to improve screening rates.     

Breakthrough pain in cancer patients: new therapeutic approaches to an old challenge

Breakthrough pain is a well recognized but ill-defined phenomenon that occurs commonly in the presence of otherwise stable, persistent pain. It is defined now as a "transient pain episode that occurs, or breaks through from the otherwise stable background pain." Breakthrough pain is usually associated with moderate to severe pain and may form a predictor of poor response to treatment with routine pharmacotherapy. Breakthrough pain is also associated with functional impairment and psychological distress. The assessment and treatment should be multidimensional. Although primary therapies such as chemotherapy, radiation treatment, and surgical options are explored, the mainstay of treatment is pharmacotherapy. Nonpharmacologic methods, such as orthotic devices and joint stabilizations along with behavioral methods, should be explored. Anesthetic and neurosurgical procedures are performed on a limited number of patients based on the prognosis, intractable nature of pain, and favorable risk/benefit ratio. Newer oral transmucosal fentanyl offers a favorable pharmacokinetic and pharmacodynamic profile and ease of administration.     

Membrane phospholipid abnormalities in postmortem brains from schizophrenic patients

Previous studies in schizophrenia have shown alterations in membrane phospholipids and polyunsaturated fatty acids. However, these studies have primarily examined peripheral (non-neuronal) cell types. The purpose of the present study was to examine whether the membrane deficits seen in peripheral tissues are also observed in the brain. The caudate was the primary region of interest for this study. Using high-pressure liquid chromatography in conjunction with an evaporative light-scattering detector, we first measured the level of various membrane phospholipids (PL) in schizophrenic (n=11) and control groups with (n=7) and without (n=14) other mental disorders. Polyunsaturated fatty acids (PUFAs) were then determined by capillary gas chromatography. Within groups, there are no significant correlations between membrane PL levels and other collection and demographic parameters including age, postmortem interval, storage time and brain weight. Significantly lower amounts of phosphatidylcholine and phosphatidylethanolamine were found in postmortem brain tissue from schizophrenic patients than in those from control groups, even after accounting for potential confounds. In addition, strong reductions of total PUFAs and saturated fatty acids were found in schizophrenic brains, relative to control brains. Specifically, the reduced PUFAs were largely attributable to decreases in arachidonic acid (AA) and, to a lesser extent, its precursors, linoleic and eicosadienoic acids. There are no significant differences between the control groups with and without other mental disorders. The present findings suggest that deficits identified in peripheral membranes may also be present in the brain from schizophrenic patients. Such a deficit in membrane AA may contribute to the many biological, physiological, and clinical phenomena observed in schizophrenia.     

Hemodynamic effects of carbon dioxide insufflation during endoscopic vein harvesting

BACKGROUND: A prospective study was performed assessing the hemodynamic effects of carbon dioxide (CO2) insufflation during endoscopic vein harvesting (EVH) using the Guidant Vasoview Uniport system. METHODS: Five hemodynamic and respiratory parameters (end-tidal carbon dioxide, arterial partial pressure of carbon dioxide, mean arterial pressure, mean pulmonary arterial pressure, and cardiac output), were measured in 100 consecutive patients undergoing EVH with CO2 insufflation. Data were obtained prior to commencement of EVH, 15 minutes after commencement, and 5 minutes after completion of the vein harvesting. RESULTS: No adverse hemodynamic effects were observed during CO2 insufflation. Specifically, average mean arterial pressure went from 88.77+/-9.64 to 89.13+/-8.60 to 88.24+/-8.71 mm Hg before, during, and after endoscopic vein harvesting (p = 0.291). Likewise, average mean pulmonary artery pressures were 19.76+/-4.75, 20.05+/-4.48, and 20.05+/-4.62 mm Hg (p = 0.547); and average cardiac output was 4.25+/-0.74, 4.22+/-0.73, and 4.23+/-0.69 L/min (p = 0.109) at those three intervals. Additionally, there was no evidence of significant systemic absorption of CO2 as reflected in average arterial PCO2, which remained steady at 37.42+/-5.19, 37.51+/-4.59, and 38.10+/-4.80 mm Hg (p = 0.217); and average end-tidal CO2, which was 32.10+/-3.66, 32.50+/-3.47, and 32.38+/-3.33 mm Hg (p = 0.335). In a subset of 20 patients with elevated pulmonary arterial pressure (more than 32 mm Hg), there was also no significant change in any of the parameters. CONCLUSIONS: Carbon dioxide insufflation during EVH leads to no adverse hemodynamic consequences or systemic CO2 absorption. The technique appears to be safe and well tolerated.