Study of Hydrogenolytic Cleavage of Peptide-Resin Benzyl Ester Bonds for Synthesis of Protected Fragments of the Human Leukocyte Interferon

Three Roe-protected fragments of the human leukocyte interferon, LeIFA, have been synthesized: I, BOC LeIFA (99-105) (BOC-Val-Ile-Gln-Gly-Val-Gly-Val); II, BOC Lei FA (116-119) (BOC-Ile-Leu-Ala-Val); III, BOC LeIFA (123-126) (BOC-Phe-Gln-Arg(Tos)-Ile). The presence of the Boc-group was desired so that these peptides could serve as intermediates in fragment condensation toward larger segments of interferon. To achieve these intermediates, a study was desirable on three methods of cleavage of the benzyl ester-polymer bonds. It was found that hydrogenolysis with hydrogen and palla­dium generated in situ was distinctly superior to transfer hydrogenation with ammonium formate or cyclohexene. An effective swelling of the peptide-resin to allow penetration of palladium acetate into the matrix and mobility of the peptide chains on the resin to expose the bonzyl ester bond to hydrogenolysis appear to be essential conditions for the best cleavage.

Design, Synthesis and Biological Evaluation of Antagonists of LHRH by Criteria of Potency, Safety and Solubility

Some analogs of Antide and congeners with higher water solubility have been synthesized by substitutions in positions 1, 5 or 6 with hydrophilic residues. In position 1, D-3-Qal has been incorporated in four peptides and D-3-Pal in one peptide. In positions 5 and 6, D and L-3-Pal, PzAla and (DSer)Lys have been tried. In one peptide, D—(AcDSer)Lys was substituted in position 6.

Most of the new analogs had lower AOA (antiovulatory activity) than the parent compounds but three potent analogs were identified. The first one, [N — Ac— D — 3-Qal1,DpClPhe2,D— 3-Pal3,c-PzACAla5,D — PicLys6,ILys8,D — Ala10]— LHRH, had 55% AOA at 0.25 μg and 100% at 0.5 μg. Its ED50 for in vitro histamine release was 171 ± 17 μg/ml which is an increase from 49±4.8 μg/ml for the parent compound with N—Ac-D-2-Nal [1].

The second analog, [N — Ac— D — 2-Nal1,DpClPhe2,D — 3-Pal3,PicLys5,D — (DSer)Lys6,ILys8,D—Ala10] — LHRH, had 69% AOA at 0.25 μg and 95% at 0.5 μg. This analog released somewhat more histamine than the parent analog featuring D-PicLys6, the ED50 being 18 μg/ml compared to 93 ± 11 for the parent analog.

The third analog is:

[N — Ac— D— 2-Nal1,DpClPhe2,D— 3-Pal3,c-PzACAla5,D—PzAla6,ILys8,DAla1]— LHRH. The AOA for this analog was 63% at 0.25 μg and the ED50 for histamine release 88±6.4 μg/ml.

Position 10 is Critical for Antagonists of the Luteinizing Hormone-Releasing Hormone and for Inhibition of Ovulation in Rats

Eleven analogs of the luteinizing hormone-releasing hormone (LHRH) have been designed, synthesized, bioassayed and compared for antiovulatory activity (AOA) in rats. The emphasis of design was on analogs with D–Ala10, Sar10, D–Ser10, (desGly10, NHEt), D–Abu10, Gly10, and with substitutions in position 5, 6, and 8.

High antiovulatory activity was obtained with analogs having D– Ala in position 10. Four earlier analogs, 1, 4, 11 and 13, with D– Ala in position 10, showed 67-100% AOA at 0.25 μg in rats. Analog 1 showed 60% AOA at 0.125 μg. The replacement of D–Ala10 in analog 11 by Sar10 in analog 12, retained activity, 62% vs. 67% AOA at 0.25μg, 100% vs. 90% AOA at 0.5 μg. This analog with Sar10 was the only one that did not show substantial loss of activity upon replacement of D–Ala10.

The Effects of Once-Daily Saquinavir/Minidose Ritonavir on the Pharmacokinetics of Methadone

Twelve methadone-maintained HIV-negative subjects were given saquinavir/ritonavir (SQV/rtv) 1600 mg/100 mg once daily for 14 days. Pharmacokinetic evaluations of total and unbound methadone enantiomers (R and S) were conducted before and after SQV/rtv. SQV/rtv was well tolerated, with no ACTG Grade 3-4 adverse events, no evidence of sedation, and no changes in methadone dose. For R-methadone (active isomer), C(max), AUC(0-24 h), and C(min) were unchanged, but percent unbound 4 hours after dosing was reduced by 12%. For S-methadone, no differences in pharmacokinetic parameters of total drug were seen, but unbound concentrations were reduced by 15% and 21% at 4 and 24 hours after dosing, respectively. SQV trough concentrations exceeded the anticipated EC(50) (50 ng/mL) in 10/12 subjects, persisting for at least 6 hours after the final dose in 4/6 subjects. Once-daily SQV/rtv in methadone-maintained subjects is safe and not associated with any clinically significant interaction with methadone during 14 days of concomitant administration.

Medicine and science in the fight against doping in sport

The fight against doping in sports commenced as a result of the death of a Danish cyclist during the Rome Olympic Games in 1960. The International Olympic Committee (IOC) established a Medical Commission (IOC-MC) which had the task of designing a strategy to combat the misuse of drugs in Olympic Sport. Some International Sport Federations (IF) and National Sports Federations followed suit, but progress was modest until the world's best male sprinter was found doped with anabolic steroids at the Olympic Games in Seoul in 1988. Further progress was made following the cessation of the cold war in 1989 and in 1999 public authorities around the world joined the Olympic Movement in a unique partnership by creating WADA--the 'World Anti-Doping Agency'. The troubled history of the anti-doping fight from the 1960s until today is reviewed. In particular, the development of detection methods for an ever increasing number of drugs that can be used to dope is described, as are the measures that have been taken to protect the health of the athletes, including those who may need banned substances for medical reasons.

Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement

The incidence of anterior cruciate ligament (ACL) injury remains high in young athletes. Because female athletes have a much higher incidence of ACL injuries in sports such as basketball and team handball than male athletes, the IOC Medical Commission invited a multidisciplinary group of ACL expert clinicians and scientists to (1) review current evidence including data from the new Scandinavian ACL registries; (2) critically evaluate high-quality studies of injury mechanics; (3) consider the key elements of successful prevention programmes; (4) summarise clinical management including surgery and conservative management; and (5) identify areas for further research. Risk factors for female athletes suffering ACL injury include: (1) being in the preovulatory phase of the menstrual cycle compared with the postovulatory phase; (2) having decreased intercondylar notch width on plain radiography; and (3) developing increased knee abduction moment (a valgus intersegmental torque) during impact on landing. Well-designed injury prevention programmes reduce the risk of ACL for athletes, particularly women. These programmes attempt to alter dynamic loading of the tibiofemoral joint through neuromuscular and proprioceptive training. They emphasise proper landing and cutting techniques. This includes landing softly on the forefoot and rolling back to the rearfoot, engaging knee and hip flexion and, where possible, landing on two feet. Players are trained to avoid excessive dynamic valgus of the knee and to focus on the "knee over toe position" when cutting.

Gender verification of female athletes

The International Olympic Committee (IOC) officially mandated gender verification for female athletes beginning in 1968 and continuing through 1998. The rationale was to prevent masquerading males and women with "unfair, male-like" physical advantage from competing in female-only events. Visual observation and gynecological examination had been tried on a trial basis for two years at some competitions leading up to the 1968 Olympic Games, but these invasive and demeaning processes were jettisoned in favor of laboratory-based genetic tests. Sex chromatin and more recently DNA analyses for Y-specific male material were then required of all female athletes immediately preceding IOC-sanctioned sporting events, and many other international and national competitions following the IOC model. On-site gender verification has since been found to be highly discriminatory, and the cause of emotional trauma and social stigmatization for many females with problems of intersex who have been screened out from competition. Despite compelling evidence for the lack of scientific merit for chromosome-based screening for gender, as well as its functional and ethical inconsistencies, the IOC persisted in its policy for 30 years. The coauthors of this manuscript have worked with some success to rescind this policy through educating athletes and sports governors regarding the psychological and physical nature of sexual differentiation, and the inequities of genetic sex testing. In 1990, the International Amateur Athletics Federation (IAAF) called for abandonment of required genetic screening of women athletes, and by 1992 had adopted a fairer, medically justifiable model for preventing only male "impostors" in international track and field. At the recent recommendation of the IOC Athletes Commission, the Executive Board of the IOC has finally recognized the medical and functional inconsistencies and undue costs of chromosome-based methods. In 1999, the IOC ratified the abandonment of on-site genetic screening of females at the next Olympic Games in Australia. This article reviews the history and rationales for fairness in female-only sports that have led to the rise and fall of on-site, chromosome-based gender verification at international sporting events.

Mercury content in amalgam tattoos of human oral mucosa and its relation to local tissue reactions

Mucosal biopsies from 48 patients with and 9 without amalgam tattoos were analysed with respect to their mercury content, distribution of mercury in the tissue, and histological tissue reactions. The distribution of mercury was assessed by autometallography (AMG), a silver amplification technique. The mercury content was determined by energy dispersive X-ray fluorescence (EDXRF), a multielemental analysis. Mercury was observed in connective tissue where it was confined to fibroblasts and macrophages, in vessel walls and in structures with the histological character of nerve fibres. A correlation was found between the histopathological tissue reaction, the type of mercury deposition, the intensity of the AMG reaction, and the mercury content. Mercury was also found in patients with amalgam dental fillings but without amalgam tattoos.

Blood sampling in doping control. First experiences from regular testing in athletics

We report the results from blood sampling taken for the first time during doping control in athletics. The study includes samples from 99 athletes tested during IAAF-meetings in 1993-94. Blood doping with allogenic blood was not detected. The distribution of haemoglobin levels in athletes did not differ markedly from that found in controls. Erythropoietin (EPO) values were markedly lower in athletes than in controls, and 58% had EPO lower than the detection limit for the assay. This may be due to high-altitude residence prior to testing. Measurements of growth hormone (GH) and insulin-like growth factor 1 did not suggest GH-misuse in any athlete tested. One third of the male athletes had testosterone levels that were lower than the normal reference interval. This may at least partly be due to the combination of sampling at night and after strenuous exercise. One female athlete was found to have a grossly elevated testosterone level. In conclusion, the present results show the importance of taking into account the special circumstances during sampling when interpreting results from blood testing in athletes. Future research should focus on developing more sensitive and specific tests to detect doping with endogenous substances such as GH and EPO.

Gender verification in competitive sports

The possibility that men might masquerade as women and be unfair competitors in women's sports is accepted as outrageous by athletes and the public alike. Since the 1930s, media reports have fuelled claims that individuals who once competed as female athletes subsequently appeared to be men. In most of these cases there was probably ambiguity of the external genitalia, possibly as a result of male pseudohermaphroditism. Nonetheless, beginning at the Rome Olympic Games in 1960, the International Amateur Athletics Federation (IAAF) began establishing rules of eligibility for women athletes. Initially, physical examination was used as a method for gender verification, but this plan was widely resented. Thus, sex chromatin testing (buccal smear) was introduced at the Mexico City Olympic Games in 1968. The principle was that genetic females (46,XX) show a single X-chromatic mass, whereas males (46,XY) do not. Unfortunately, sex chromatin analysis fell out of common diagnostic use by geneticists shortly after the International Olympic Committee (IOC) began its implementation for gender verification. The lack of laboratories routinely performing the test aggravated the problem of errors in interpretation by inexperienced workers, yielding false-positive and false-negative results. However, an even greater problem is that there exist phenotypic females with male sex chromatin patterns (e.g. androgen insensitivity, XY gonadal dysgenesis). These individuals have no athletic advantage as a result of their congenital abnormality and reasonably should not be excluded from competition. That is, only the chromosomal (genetic) sex is analysed by sex chromatin testing, not the anatomical or psychosocial status. For all the above reasons sex chromatin testing unfairly excludes many athletes. Although the IOC offered follow-up physical examinations that could have restored eligibility for those 'failing' sex chromatin tests, most affected athletes seemed to prefer to 'retire'. All these problems remain with the current laboratory based gender verification test, polymerase chain reaction based testing of the SRY gene, the main candidate for male sex determination. Thus, this 'advance' in fact still fails to address the fundamental inequities of laboratory based gender verification tests. The IAAF considered the issue in 1991 and 1992, and concluded that gender verification testing was not needed. This was thought to be especially true because of the current use of urine testing to exclude doping: voiding is observed by an official in order to verify that a sample from a given athlete has actually come from his or her urethra. That males could masquerade as females in these circumstances seems extraordinarily unlikely. Screening for gender is no longer undertaken at IAAF competitions.

Synthesis and bioassay of LHRH-antagonists with N-Ac-D-O-phenyltyrosine and N-Ac-D-3-(2-dibenzofuranyl)alanine in position 1

N-Ac-D-O-phenyltyrosine was synthesized via the corresponding azlactone. Resolution of the DL methyl esters was achieved by Subtilisin Carlsberg. Treatment with palladium(II) acetate in trifluoroacetic acid converted N-Ac-D-O-phenyltyrosine into N-Ac-D-3-(2-dibenzofuranyl)alanine. These two amino acids were incorporated instead of N-Ac-D-2-Nal into position 1 of the LHRH-antagonist (N-Ac-D-2-Nal1, D-p-ClPhe2, D-3-Pal3, c-PzACAla5, D-PicLys6, ILys8,D-Ala10)-LHRH. The more rigid N-Ac-D-3-(2-dibenzofuranyl)alanine was structurally more effective than N-Ac-D-O-phenyltyrosine; the AOAs for the corresponding analogs were 82 and 38%, respectively, at 0.5 micrograms. Replacement of c-PzACAla in position 5 by O-phenyltyrosine significantly decreased potency.

Perioral dermabrasion: clinical and experimental studies

From 1985 through 1989, 54 patients with wrinkles around the lips and in the chin area were treated by dermabrasion. Significant improvement, lasting longer than three years, was achieved using both types of abrading tool: the wire brush and the diamond fraise. The side effects of dermabrasion were permanent but very slight bleaching in 66% of the patients and formation of milia in less than 20%. The surgical technique is described in detail. Dermabrading tools were tested at different speeds on excess cheek skin at facelift. Histological examination showed that the diamond fraise left a smooth abraded surface and the wire brush left an uneven surface. EMLA cream, usually used for skin surface analgesia, was tested as an adjunct to anesthesia in dermabrasion. EMLA's analgesic performance alone was insufficient in the sensitive perioral region, but it elevated pain threshold and decreased the required amount of local anesthetic solution. Five types of dressing were used and the speed of epithelialization and postoperative comfort were compared. At present Vigilon is the most suitable dressing for dermabrasion. The main advantage of dermabrasion over the chemical peel is the absence of severe depigmentation.

Central (third) fat pad of the upper eyelid

A clinical study on the surgical anatomy of the upper-eyelid fat pads was performed on 55 consecutive patients who underwent a blepharoplasty. It was confirmed that the periorbital fat is encapsulated in compartments and that the number of fat pads varies. In 56% of the cases there were two fat pads and in the 44% three fat pads in the upper eyelid. The third fat pad is anatomically and histologically an accessory medial extension of the lateral fat pad. However, for the sake of clarity, the term central fat pad of the upper eyelid is proposed as a denominator of this structure. The purpose of this article is to make the less experienced surgeons aware of variations in the configuration of the periorbital fat and to remind them that after two fat pads are removed from the upper eyelid there might still be a third.

Superiority of an antagonist of the luteinizing hormone releasing hormone with emphasis on arginine in position 8, named Argtide

In the research for more potent antagonists of the luteinizing hormone releasing hormone (LHRH), 13 new peptides with emphasis on arginine in position 8 were designed, synthesized and tested for anti-ovulatory activity (AOA). Two very potent analogs were achieved. N-Ac-D-3-Qal, D-pClPhe, D-3-Pal, Ser, cis-PzACA1a, D-PicLys, Leu, Arg, Pro, D-AlaNH2 showed 63% AOA at 0.125 microgram and 89% at 0.25 microgram, and an ED50 of 30.8 +/- 0.59 and presently may be the most promising antagonist reported. It is named Argtide. N-Ac-D-3-Qal, D-pClPhe, D-3-Pal, Ser, cis-PzACA1a, D-PicLys, Val, Arg, Pro, D-AlaNH2 showed 18% AOA at 0.125 microgram. Arg8 in antagonists may be significant for receptor binding.

Thrombin-inhibitory capacity of the injured vessel wall

The present study examined the appearance of thrombin activity in vitro after single and repeated in vivo balloon injury of the rabbit aorta. The in vitro ability of the injured vessel wall to bind and subsequently inhibit thrombin in the presence of defibrinogenated plasma was also assessed. Thrombin activity was assayed by measuring the levels of fibrinopeptide A generated in the presence of fibrinogen. These findings were correlated with the changes observed in light and electron microscopy. Thrombin activity on the vessel wall was increased five minutes and three hours after the initial and the repeated injury, and returned to control values one week after the initial injury. When the inhibition of thrombin was assayed in the presence of defibrinogenated plasma, a diminished inhibition capacity was observed after the repeated injury, which correlated with deposition of fibrin and an enhanced inflammatory reaction as measured by the density of granulocytes covering the injured neointima. Decreased thrombin inhibitory capacity of the injured neointima appears to be linked with its increased thrombogenicity.

Metabolic stability of the LHRH antagonist antide to cell-surface peptidases

The susceptibility to hydrolysis of LHRH and the decapeptide analogue Antide has been compared. The hydrolysis of LHRH by pig kidney brush border membranes is inhibited by phosphoramidon (I50 = 5.6 nM) implicating endopeptidase-24.11 in the initiation of hydrolysis. Under conditions in which LHRH is fully degraded by brush border membranes, Antide was completely resistant to hydrolysis. Similar results were obtained with purified preparations of both endopeptidase-24.11 and angiotensin converting enzyme. These data confirm that the remarkable duration of action of Antide is due principally to its stability to hydrolysis by cell-surface peptidases.

Increased potency of antagonists of substance P having asparagine in position 6

The general structure of antagonists of substance P (SP) which was found with the development of Spantide and analogs based on Spantide served for further refinement. The antagonistic potency was tested in vitro on guinea pig ileum and taenia coli. It was unexpectedly found that introduction of Asn6 gave rise to a considerable increase in potency. The exchange of Gln6 for Asn6 entails the shortening of the side chain by one CH2 unit and seems slight for steric advantages and potency increase. The analog [D-Arg1,D-Cl2Phe5,Asn6,D-Trp7,9,Nle11]SP had pA2 values of 7.4 (ileum) and 8.0 (taenia coli). We then used this sequence as a new lead to introduce new changes, which were made in positions 1, 3, 5, 7 and 9. It was found that Arg1 is important, but Lys3 can be exchanged. The Pal3 derivative had pA2 values of 8.1 and 8.0 and the Nle3 counterpart had 7.7 and 7.4 D-Cl2Phe is an effective substituent in position 5. D-Trp in positions 7 and 9 were superior to other alternatives.

Antide and related antagonists of luteinizing hormone release with long action and oral activity

Antide is the decapeptide N-Ac-D-Nal(2),D-Phe(pCl),D-Pal(3),Ser,Lys(Nic),D-Lys(Nic),Leu,Lys(iPr),P ro,D- Ala-NH2 [Nal(2) represents 3-(2-naphthyl)alanine; Phe(p-Cl) represents 3-(4-chlorophenyl)alanine; Pal(3) represents 3-(3-pyridyl)alanine; Lys(Nic) represents N epsilon-nicotinoyllysine; Lys-(iPr) represents N epsilon-isopropyllysine], which is an antagonist of luteinizing hormone-releasing hormone (LHRH), which has high antiovulatory activity, releases negligible histamine, and is scheduled for scale-up, safety testing, and evaluation in the experimental primate and in clinical medicine. Thirty-five more peptides were synthesized, designed on antide with variations in positions 5-8. Of these, N-Ac-D-Nal(2),D-Phe(pCl),D-Pal(3),Ser,Lys(Pic),cis-D- Ala(PzAC),Leu,Lys(iPr),Pro,D-Ala-NH2 [Lys(Pic) represents N epsilon-picoloyllysine; Ala(PzAC) represents 3-(4-pyrazinylcarbonylaminocyclohexyl)alanine] was not only the most potent but also had higher antiovulatory activity than antide--i.e., 73% per 0.25 microgram and 100% per 0.5 microgram vs. 36% per 0.5 microgram and 100% per 1.0 microgram. Antide showed significant (P less than 0.001) duration of action when injected at a dose of 10 micrograms 44 hr before injection of 50 ng of the agonist [D-Qal(3)6]LHRH [Qal(3) represents 3-(3-quinolyl)alanine]. Antide showed oral antiovulatory activity at 600 micrograms (73%) and at 1200 micrograms (100%) with negligible difference between water and corn oil oral formulations.

Blockade of sensory nerve mediated contraction of the rabbit iris sphincter by a series of novel tachykinin antagonists

Electrical stimulation of the isolated rabbit iris sphincter muscle in the presence of atropine gives rise to a contraction that can be blocked by tachykinin antagonists. The ability of a series of novel tachykinin antagonists to inhibit the contractile effect of SP on the guinea-pig taenia coli and to suppress the electrically evoked contraction of the atropinized rabbit iris sphincter was tested. Several of the novel antagonists were found to be more potent in terms of pA2 and pIC50 values than the two previously described analogs, [D-Pro2, D-Trp7,9]SP9(1-11) and [D-Arg1, D-Trp7,9, Leu11]SP-(1-11) (Spantide). Apart from D-Trp in positions 7 and 9 the characteristic features of the potent novel antagonists were D-Cl2Phe (or D-Cys(Bzl] in position 5, Asn in position 6 and Nle in position 11. In addition Pal in position 3 seemed to offer an enhanced potency.

Design, synthesis and bioassays of antagonists of LHRH which have high antiovulatory activity and release negligible histamine

Potent antagonists of the luteinizing hormone releasing hormone have been achieved which release negligible histamine. [N-Ac-D-2-Nal1, D-pClPhe2, D-3-Pal3, NicLys5, D-NicLys6, ILys8, D-Ala10]-LHRH showed 100%AOA/1 microgram and 36%/0. 5 micrograms; ED50 greater than 300. [N-Ac-D-2-Nal1,D-pClPhe2,D-3-Pal3, PicLys5, D-PicLys6, ILys8, D-Ala10]-LHRH showed 100% AOA/0.5 micrograms and 40%/0.25 micrograms; ED50, 93 +/- 11, and is the most potent of 52 new peptides. These antagonists feature designs with weakly basic acylated D-Lys6, notably D-NicLys6 and D-PicLys6 and alkylated Lys8 or Orn8, e.g., ILys8 and IOrn8, and NicLys5 and PicLys5. Concepts included balanced overall basicity, superiority of ILys8 and IOrn8 which are sequence dependent and sensitivity of positions 5 and 6 for potency.

Design and synthesis of antagonists of substance P

Synthesis and bioassay of about 65 analogs of substance P (SP) over five years yielded the antagonist [D-Arg1,D-Trp7,9,Leu11]-SP, which was named Spantide, and which was used by many investigators as a "tool". Spantide served as a reference antagonist for the design of 47 new peptides toward the goal of more potent inhibitors. Designs emphasized analogs with D-Trp7, D-Trp9, D-Trp10, D-pClPhe10, Nle11, Leu11, Ile11 and Met11, etc. Twenty-one/47 antagonists were superior in potency to that of Spantide, the best was [D-Arg1,D-Na1(5), D-Trp7,9,Nle11]-SP which required a 255-fold increase in SP concentration to give 50% of the maximum response at a concentration of 10(-5)M of the antagonist; this potency is ca. 5 times that of Spantide. For certain, but not all pairs of undecapeptides and truncated analogs, the undecapeptides may be significantly more potent than the truncated counterparts.