The asymmetric synthesis of arginine mimetics: derivatives of (S)-2-, 3- and 4-amidinophenylalanine suitable for incorporation into enzyme inhibitors and/or peptides.

The specific inhibition of trypsin-like serine proteases has become an important therapeutic target. These proteases have been implicated in several physiological and pathophysiological processes, including blood coagulation, digestion, and inflammation. Proteases of this class cleave polypeptide chains C-terminal to a basic residue (arginine or lysine). It has been shown that selectivity for a particular serine protease can be conferred based upon the structural moiety incorporated in the P1 position. In this regard, the three isomers (ortho, meta, and para) of amidinophenylalanine represent modified arginine residues and are important synthetic targets. Herein, a convenient asymmetric synthesis of (S)-Nalpha-(tert-butyloxycarbonyl)-2-, (S)-Nalpha-(tert-butyloxycarbonyl)-3-, and (S)-Nalpha-(tert-butyloxycarbonyl)-4-amidinophenyl-alanine N,O-dimethylamides (Weinreb amides) will be described. These derivatives represent key synthetic intermediates for the synthesis of enzyme inhibitors because the amidine can be readily orthogonally protected, while the Weinreb amide is easily converted to a variety of electrophilic carbonyls via reduction to the corresponding aldehyde or by reaction with various lithiated heterocycles. Likewise, the Weinreb amide can be reduced to the aldehyde and subsequently oxidized to the corresponding carboxylate, which is suitable for solid- or solution-phase peptide synthetic strategies.

Potent and selective bicyclic lactam inhibitors of thrombin: Part 2: P1 modifications.

The synthesis and antithrombotic activity of a series of nonpeptide bicyclic thrombin inhibitors is described. We have explored the SAR with modifications to the P1 site. The introduction of arginine mimetics at the P1 site led to potent and selective thrombin inhibitors.

Conformational analysis of the dipeptide taste ligand L-aspartyl-D-2-aminobutyric acid-(S)-alpha-ethylbenzylamide and its analogues by NMR spectroscopy, computer simulations and X-ray diffraction studies.

A dipeptide taste ligand L-aspartyl-D-2-aminobutyric acid-(S)-alpha-ethylbenzylamide was found to be about 2000 times more potent than sucrose. To investigate the molecular basis of its potent sweet taste, we carried out conformational analysis of this molecular and several related analogues by NMR spectroscopy, computer simulations and X-ray crystallographic studies. The results of the studies support our earlier model that an L-shape molecular array is essential for eliciting sweet taste. In addition, we have identified an aromatic group located between the stem and the base of the L-shape, which is responsible for enhancement of sweetness potency. In this study, we also assessed the optimal size of the essential hydrophobic group (X) and the effects of the chirality of the second residue toward taste.

Sweet and bitter taste: structure and conformations of two aspartame dipeptide analogues.

The synthesis and X-ray diffraction analysis of two dipeptide taste ligands have been carried out as part of our study of the molecular basis of taste. The compounds L-aspartyl-D-alpha-methylphenylalanine methyl ester [L-Asp-D-(alpha Me)Phe-OMe] and L-aspartyl-D-alanyl-2,2,5, 5-tetramethylcyclopentanyl ester [L-Asp-D-Ala-OTMCP] elicit bitter and sweet taste, respectively. The C-terminal residues of the two analogues adopt distinctly different conformations in the solid state. The aspartyl moiety assumes the same conformation found in other dipeptide taste ligands with the side-chain carboxylate and the amino groups forming a zwitterionic ring with a conformation defined by psi, chi 1 = 157.7 degrees, -61.5 degrees for L-Asp-D-Ala-OTMCP and 151.0 degrees, -68.8 degrees for L-Asp-D-(alpha Me)Phe-OMe. In the second residue, a left-handed helical conformation is observed for the (alpha Me)Phe residue of L-Asp-D-(alpha Me)Phe-OMe with phi 2 = 49.0 degrees and psi 2 = 47.9 degrees, while the Ala residue of L-Asp-D-Ala-OTMCP adopts a semi-extended conformation characterized by dihedral angles phi 2 = 62.8 degrees and psi 2 = -139.9 degrees. The solid-state structure of the bitter L-Asp-D-(alpha Me)Phe-OMe is extended: while the crystal structure of the sweet L-Asp-D-OTMCP roughly adopts the typical L-shaped structure shown by other sweeteners. The data of L-Asp-D-(alpha Me)Phe-OMe are compared with those of its diastereoisomer L-Asp-L-(alpha Me)Phe-OMe. Conformational analysis of the two taste ligands in solution by NMR and computer simulations agrees well with our model for sweet and bitter tastes.

Effect of oral contraceptives on leukocyte phagocytic activity and plasma levels of prostaglandin E2 and thromboxane B2 in normal menstruating women.

Mononuclear and polymorphonuclear cells were isolated from the peripheral blood of normal menstruating women. Four of the subjects were not using oral contraceptives and five were taking various formulations. The women were tested once a week for 12 consecutive weeks. Plasma levels of 6-keto-prostaglandin F2 alpha (6-KF), prostaglandin E2 (PGE2), thromboxane B2 (TxB2), estrogen, and progesterone were measured by specific radioimmunoassays. The phagocytic activity of the mononuclear and polymorphonuclear cells isolated from the peripheral blood was measured with a bacterial phagocytosis and killing assay. The phagocytic activity of both types of cells was depressed perimenstrually in both groups of women. However, examination of individuals showed that those subjects not taking oral contraceptives had a worsening of phagocytic activities with approaching menses while the oral contraceptive subjects generally had an improving of these activities at this time. We were unable to correlate the phagocytic activities with either hormone or prostaglandin levels in the plasma of these subjects. However, the subjects on oral contraceptives had significantly lower levels of PGE2 and TxB2 than those women who were not using oral contraceptives.

Experience with a cost-effective crossmatch protocol.

Pretransfusion blood samples were routinely tested for ABO group, Rh type, and the presence of unexpected red blood cell antibodies. Patients who had unexpected red blood cell antibodies received transfusions of blood that was crossmatched using an immediate spin test, a 37 degrees C incubation step, and an indirect antiglobulin test. Patients who did not have unexpected red blood cell antibodies received transfusions with blood that was crossmatched by an immediate spin crossmatch only. Because the average immediate spin crossmatch required only 3.25 minutes to be performed, crossmatches were not done for patients without unexpected antibodies until blood was actually requested to be issued for transfusion. During the first 8 1/2 months this protocol was used, 27,742 crossmatches were performed and 46,959 unnecessary crossmatches were avoided, thus reducing direct costs by at least +49,300. This protocol also allowed for optimal blood inventory control and minimized the outdating of units of blood to only 0.19%.

Depressed mononuclear cell phagocytic activity associated with menstruation.

The peak of the normal distribution curve for pelvic inflammatory disease occurs near the onset of menses. This study was undertaken to determine if there were changes in the cell-mediated immunity of normal menstruating women which could explain the increase in inflammatory disease. The cellular immune response of 8 normal women, measured by number of T- and B-cells and response of mononuclear cells to stimulation with mitogen, was not dependent on the menstrual cycle. However, there was a significant decrease in phagocytic activity of mononuclear cells early in the cycle. The depressed phagocytic activity was not altered by treating the subjects with ibuprofen.

Experience with the routine use of an abbreviated crossmatch.

Three years' experience with the routine use of an abbreviated crossmatch procedure is reported. If a patient had no known history of and/or no currently demonstrable unexpected antibodies, ABO and Rh type specific blood was crossmatched at the time of need by using an immediate spin saline abbreviated crossmatch. Once blood was issued, both a 37 degrees C incubation and an antiglobulin crossmatch were done using the same tube employed for the abbreviated crossmatch. This served as a check that clinically significant antibodies were not overlooked. None of the 19,818 patients transfused following an abbreviated crossmatch suffered an acute hemolytic transfusion reaction as a result of this strategy; however, two patients may have manifested asymptomatic hemolysis. This approach to compatibility testing might be appealing to hospitals faced with fiscal limitations and new regulations affecting hospital reimbursement.

Effects of prostaglandin E2 analogue suppository on blood loss in suction abortion.

The purpose of the present clinical investigation was to determine the effect of preoperative treatment with a long-acting prostaglandin suppository containing 9-deoxo-16,16-dimethyl-9-methylene prostaglandin E2 on uterine blood loss in patients undergoing preoperative cervical dilatation before transcervical abortion. Ninety-five young women in the ninth to 14th week of gestation were randomly assigned to one of two groups. Patients in group 1 were treated with a long-acting prostaglandin suppository and group 2 patients acted as control subjects. At the end of three hours, patients in both groups underwent abortion with careful intraoperative measurement of blood loss in both groups. The blood loss in the prostaglandin-treated group was significantly lower than that in the control group (69.0 +/- 14.1 mL versus 151.1 +/- 26.6 mL). The difference in intraoperative blood loss was observed at all gestations between nine and 14 weeks. There was significantly greater dilation of the cervix after prostaglandin treatment (mean difference, 4.58 mm; P less than .005).

Safety and efficacy of vaginal prostaglandin E2 suppositories in the management of third-trimester fetal demise.

Prostaglandin E2 vaginal suppositories are well established in the management of intrauterine fetal demise in the second trimester of pregnancy. However, approval for their use in the third trimester has been withheld pending evaluation of safety and efficacy. In this study 46 patients with intrauterine fetal demise in the third trimester were managed in a similar fashion except that only a 10-mg dose of prostaglandin E2 was employed. Forty-four of the 46 patients were delivered successfully. One patient experienced a cervical laceration that necessitated a hysterectomy; in her, oxytocin was used to supplement the prostaglandin. It appears that prostaglandin E2 vaginal suppositories can be used safely in the management of fetal demise in the third trimester of pregnancy. Use of a lower dose of the medication as well as tocodynamometry is recommended because the absorption of and sensitivity to this medication vary from patient to patient. The frequency of administering the medication should depend on the patient's response rather than on any given formula.

PIP: Prostaglandin E2 (PGE2) vaginal suppositories are well established in the management of intrauterine fetal demise in the 2nd trimester of pregnancy. However, approval for their use in the 3rd trimester has been withheld pending evaluation of their safety and efficacy. In this study, 46 patients with intrauterine fetal demise in the 3rd trimester were managed in a similar fashion except that only a 10 mg dose of PGE2 was employed. 44 of the 46 patients were delivered successfully. 1 patient experienced a cervical laceration that necessitated a hysterectomy; in her, oxytocin was used to supplement the PG. It appears that PGE2 vaginal suppositories can use used safely in the management of fetal demise in the 3rd trimester. Use of a lower dose of the medication as well as tocodynamometry is recommended because of the absorption and sensitivity to this medication vary from patient to patient. The frequency of drug administration should depend on the patient's response rather than on any given formula.

Preoperative cervical dilatation with a single long-acting prostaglandin analog suppository. An alternative to traumatic mechanical dilatation before surgical evacuation.

A single vaginal suppository containing 1 mg of 15-methyl prostaglandin F2 alpha methyl ester induced cervical dilatation in 60 patients requesting surgical termination of pregnancy. Forty-two percent of the patients required no further dilatation. Even when further dilatation was required, it was performed with considerable ease due to the softening effects of the prostaglandin on the cervix. The use of this agent may be of value in preventing complications resulting from mechanical dilatation of the cervix.

Prostaglandin E2 vaginal suppositories in the treatment of intractable late-onset postpartum hemorrhage. A case report.

Late-onset postpartum hemorrhage may sometimes be refractory to conventional methods of treatment. Prostaglandin E2 vaginal suppositories have been described as effective in arresting immediate postpartum hemorrhage secondary to uterine atony. This is the first report of the use of this treatment in a patient with massive hemorrhage three weeks after delivery.

Unilateral renal agenesis associated with vaginal or cervical fistula and anomalous uterine development.

Two patients with unexplained profuse vaginal discharge were noted to have anomalous uterine development associated with renal agenesis. Fistulous communication between a mesonephric duct remnant and the vagina or cervix was noted as the cause of the discharge. A previous report by one of the authors described two similar cases. Physicians should be alert to this syndrome as a cause of leukorrhea.

Oral contraceptives and hepatic vein thrombosis.

The purpose of this paper is to report on three cases of the Budd-Chiari syndrome in young women who were taking oral contraceptives. Two patients survived, with gradual resolution of hepatomegaly and ascites following discontinuance of the birth control pills. One death occurred soon after the patient's admission to the hospital. The pathophysiology of this phenomenon involves two major aspects. Oral contraceptives are known to cause a hypercoagulation state as well as a direct effect on the blood vessels. In this series the combination of hypercoagulation and progressive occlusion of the vessels in patients on oral contraceptives appeared to lead to the development of thrombosis of the liver vessels.

Role of oral contraceptive agents in the pathogenesis of liver tumors.

Since the introduction of oral contraceptive steroids in 1960 there has been a sharp increase in the incidence of benign liver tumors. Epidemiologic and other evidence links focal nodular hyperplasia and hepatic cell adenoma to the use of these agents. The risk increases with long-term exposure. The majority of patients were less than 35 years old. Most patients were exposed to mestranol (ME) alone or alternately with ethinylestradiol, both synthetic steroidal estrogens. Inability to demethylate ME in the smooth endoplasmic reticulum of hepatocytes may allow massive accumulation of oncogenic metabolites. This is probably a pharmacogenetic variable in a small number of women. Cholestasis, hypervascularity, induction of intracellular enzyme systems, thrombogenesis, and thickening of arterial and venous walls are other known effects of synthetic estrogens and progestogens. All may contribute to the pathogenesis of liver tumors. Many patients are asymptomatic until there is rapid expansion of the tumor. Pain occurs when Glisson's capsule stretches. Intrahepatic bleeding and liver rupture are common sequelae. Ligation of the hepatic artery may be lifesaving in the face of exsanguinating liver bleeding. Reports of regression with observation alone are encouraging. Instances of progression of unresected adenomas to rupture during subsequent pregnancy dictate avoidance of sex steroids in patients with hepatic neoplasia. Sonography, computerized axial tomography, radionuclide scans, and selective celiohepatic angiography are useful methods for the diagnosis of liver tumor in the symptomatic patient. There is a primary need to develop biochemical methods for detecting patients at risk for developing liver tumors. Epidemiologic research and central reporting of case histories are needed in the search for common factors.

Intraepithelial neoplasia of the uterine cervix in the teenager.

One hundred and seventeen teenagers with abnormal cervical cytology were evaluated using colposcopy and directed biopsies. Eighty-eight cases of cervical intraepithelial neoplasia were discovered including 24 cases of severe dysplasia or carcinoma in situ. Erradication of these lesions is essential as a preventative measure. The importance of routine cytologic screening and early evaluation of abnormal Papanicolaou smears in the teenager is emphasized.

Effect of pregnancy on liver tumor associated with oral contraceptives.

Four cases of liver adenoma associated with oral contraceptives complicating pregnancy are reported. All patients were symptomatic during pregnancy and 2 were admitted with rupture of the adenoma. One subsequently died. Increased growth and vascularity of adenomas during pregnancy is highly likely. The potential for development of lethal complications is considerable.

Unilateral tuboovarian autoamputation.

Six cases of unilateral tuboovarian absence are reviewed. In four, the peritoneal cavity contained a separate ovoid structure. In two of these, the pathologist could identify the remnant as a phagocytized ovary. In a third patient, the ovoid body was seen fixed to the contralateral ovary during laparoscopy. Subsequently, it was identified radiologically as a calcific density. In the fourth case, an intact ovary was separated from the uterus and engulfed by omentum. If a total embryogenic error or selective dysgenesis of the urogenital fold occurs, ipsilateral anomalies usually involve adjacent structures of both the urinary and genital systems. Howerver, no anomalies of the uterus and urinary structures appeared evident in any reviewed case. Therefore, adnexal torsion with subsequent infarction necrosis and autoamputation represents the most likely explanation for this phenomenon.