Lack of pineal growth during childhood

During childhood, serum melatonin concentrations drop by approximately 80%, but the 24-h melatonin excretion is stable. Arrest of pineal growth after the end of infancy has been proposed as one possible mechanism underlying that phenomenon. To test this hypothesis, we reviewed 332 magnetic resonance imaging brain studies, classified as normal, of endocrine-normal children, aged 1 day to 15 yr, and estimated the pineal and pituitary sizes. The pineal was identified in 277 of 332 magnetic resonance imaging studies (83%). The average size (mean +/- SEM) of the pineal gland (transaxial diameter, 5.6 +/- 2.1; midsagittal diameter, 5.0 +/- 2.4; planimetric area, 28.5 +/- 17.8) did not differ with age. A total of 74 of 277 pineals with cysts (26.7%) were found. The occurrence of pineal cysts was equally distributed among the different age groups (chi 2 = 11.6; df = 14; P = 0.7). Ten pineals showed more than 1 cyst (3.6%). The pituitary was identified in 325 of 332 brain images (97.9%). The average pituitary size increased by some 100% from 1 to 15 yr of age [transaxial diameter: F = 2.2; P = 0.005 (by two-way analysis of variance); midsagittal diameter: F = 3.7; P = 0.0001; planimetric area: F = 7.1; P = 0.0001]. The pituitary was slightly larger in females than in males [midsagittal diameter: F = 8.8; P = 0.003 (by two-way analysis of variance); planimetric area: F = 7.9, P = 0.005]. The data presented indicate a lack of a discernible pineal growth after age 1 yr, which contrasts with pituitary development in the same individuals. The data are in agreement with a hypothesis suggesting a growth arrest of the pineal after infancy.

Opposite directed currents induced by the transport of dibasic and neutral amino acids in Xenopus oocytes expressing the protein rBAT

Voltage- and current-clamp studies have been performed on a renal and intestinal protein (rBAT) which induces transport for neutral and dibasic amino acids when expressed in Xenopus oocytes. In current-clamp mode, superfusion with L-leucine caused a hyperpolarization while superfusion with L-arginine depolarized the oocyte. Accordingly, in voltage-clamp experiments dibasic amino acids and neutral amino acids induced inward and outward currents, respectively. The relationship between currents and substrate concentrations could be fitted by simple Michaelis-Menten kinetics. Currents induced by L-arginine and L-leucine were also voltage-dependent. pH changes from 6.25 to 8.75 did not affect the currents induced by saturating concentrations of L-arginine and L-leucine, but reversed the direction of L-histidine-induced currents from inward to outward. The reversal potentials as well as the apparent Km for L-histidine-induced currents were altered by the ambient pH. Currents induced by individual amino acids decreased during extended superfusion periods. However, extended superfusion with neutral amino acids increased dibasic amino acid induced currents, while prior superfusion with dibasic amino acid resulted in an increase of currents induced by neutral amino acids. The reversal potentials for L-leucine- and L-arginine-induced currents were depending on their intra- (after preloading) and extracellular concentrations. In conclusion, rBAT-mediated transport of neutral and dibasic amino acids is associated with net outward or inward currents, respectively, which may be caused by an exchange of neutral with dibasic amino acids.

Positive regulation by chloride channel blockers of IsK channels expressed in Xenopus oocytes

cRNA encoding the human IsK protein was injected into Xenopus oocytes and the induced IsK channels were investigated using the two-microelectrode voltage-clamp method. Niflumic acid, mefenamic acid, flufenamic acid, and 4,4'-diisothiocyanatostilbene-2,2'- disulfonic acid, which are commonly used in Xenopus oocytes to suppress endogenous Ca(2+)-activated Cl- channels, were tested for their effects on IsK channels. At low concentrations (10 microM) all compounds increased IsK amplitude and decreased the rate of IsK deactivation. At 100 microM these compounds further decreased the rate of IsK deactivation, resulting in persistent activation of IsK, similar to what has been previously described for the action of organic cross-linkers on IsK. However, at 100 microM niflumic acid and flufenamic acid decreased the time-dependent outward current, whereas 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid and mefenamic acid caused an additional increase. When Cl- was completely substituted with gluconate, IsK had somewhat altered activation properties, but niflumic acid produced similar positive regulatory effects on IsK and shifted the voltage needed to evoke half-maximal IsK activation (V1/2) by about -20 mV. In summary, these compounds positively regulate IsK, presumably by stabilizing open IsK channels.

Pheromonal Production of and Response to Optically Active Epoxydienes in Some Geometrid Moths (Lepidoptera: Geometridae)

In pheromone extracts of calling female Chiasma clathrata L. (Lepidoptera: Geometridae), a defoliator pest of alfalfa, (Z,Z,Z)-3,6,9-heptadecatriene and (Z,Z)-6,9-cis-3,4-epoxyheptadecadiene was identified. Chiral gas chromatography using a modified cyclodextrin and synthetic reference samples proved the natural epoxide to show (3R, 4S)-configuration. In field trapping tests, only the pure (3R, 4S)-enantiom er of the epoxide attracted males. The addition of the triene component was synergistic. Males of the sympatric species Tephrina arenacearia Hbn. (Lepidoptera: Geometridae) were caught only in traps with baits containing the (3S, 4R)-enantiomer [together with a previously described minor component, (Z,Z)-3,9-cis- 6,7-epoxyheptadecadiene]. In trapping tests conducted in a different biotope, Abraxas grossulariata L. (Lepidoptera: Geometridae) males were attracted by the (3S, 4R)-enantiomer, whereas the (3R, 4S)-enantiomer attracted a close relative, Abraxas sylvata Scop. (Lepidoptera: Geometridae). The present results suggest that one of the key mechanisms responsible for pheromone specificity among both the two alfalfa geometrids and the two A braxas species in their respective biotops, may be the use of different enantiomers of the same polyenederived epoxide as a sex pheromone component. It is probable that this discrimination mechanism is widespread among moth species utilizing epoxide pheromone components

Relation of elastosis to biochemical and immunohistochemical steroid receptor findings, Ki-67 and epidermal growth factor receptor (EGFR) immunostaining in invasive ductal breast cancer

We studied 1073 cases of invasive ductal breast cancer, NOS for their elastic content (DEL, ductal+periductal elastosis; TEL, tumour elastosis) and compared the findings with the results of biochemical and immunohistochemical steroid hormone receptor examination. Tumours of patients up to 50 years of age and older were examined separately. In a number of tumours elastosis was also examined in relation to Ki-67 and epidermal growth factor receptor (EGFR) immunostaining. Sensitivity and specificity of DEL and TEL for predicting the receptor, Ki-67 and EGFR findings were estimated. Sensitivity of DEL and TEL for oestrogen and progesterone receptors is dependent on the degree of tumour differentiation and the degree of elastosis, increasing from DEL 1 degree and TEL 1 degree to DEL 3 degrees and TEL 3 degrees. It was more evident in grade 1 (G1) and G2 than in G3 carcinomas. Elastosis is a useful predictor of positive receptor findings particularly in G1 and G2 tumours with moderate and high-grade elastosis. It is a similarly useful predictor of negative receptor values in G3 carcinomas. The predictive value of DEL and TEL for the results of Ki-67 and EGFR immunostaining gradually decreases with increasing elastosis, consistent with the assumption that Ki-67 and EGFR identify the degree of tumour proliferation and invasion, while elastosis correlates with the degree of differentiation of breast cancer. Elastosis is a poor predictor of Ki-67 and EGFR findings in any individual breast cancer. Moderate and high-grade elastosis points to positive steroid hormone receptor assays in G1 and G2 carcinomas. In contrast, the lack of elastosis in G3 carcinomas may indicate a negative receptor assay. Both findings have a high degree of reliability.

Abdominopelvic computed tomography in the preoperative evaluation of suspected ovarian masses

To evaluate the efficacy of computed tomography (CT) in 175 patients scheduled to undergo surgery for a suspected ovarian mass, we compared preoperative CT findings with the findings at surgery and histology. At surgery, 115 patients were found to have epithelial ovarian malignancies (20 stage 1, 7 stage II, 50 stage III and 38 stage IV) while 60 had benign pelvic tumors. CT findings were suggestive of malignancy in 4 (7%) of 60 patients with benign tumors and suggestive of benign disease in 3 (3%) of 115 patients with malignant ovarian tumors; 30% of all scans were inconclusive. The sensitivity of CT for predicting pelvic or para-aortic lymph node involvement in 42 patients who underwent lymphadenectomy was 62 and 70%, respectively; the specificity was 100%. The results of this series suggest that the routine use of CT in the preoperative evaluation of patients does not seem justified.

[Research schools in pharmacy. 5: Alexander Tschirch (1856-1939) and his students]

Alexander Tschirch was one of the most important teachers of pharmacy. In 1890 he was appointed Professor of Pharmacy and Pharmacognosy at Bern and he was a good director of his institute. The scientific programme is represented by 21 books, 388 papers and 158 dissertations. The main topics were investigations of plants (phytochemical) and researchs for pharmacopoeias. Tschirch had 2300 Students, 158 made their doctor-graduate and 11 are becoming professor. The research conditions in the pharmaceutical institute Bern were good and the research school of Tschirch has an important public and social recognition, also Tschirchs work provided the bases of the modern phytochemical research of plants.

Electrophysiologic effects and efficacy of cibenzoline on stimulation-induced atrial fibrillation and flutter and implications for treatment of paroxysmal atrial fibrillation

The effects of intravenous cibenzoline (1.5 mg/kg) on atrial vulnerability and electrophysiology were assessed in 25 patients with documented paroxysmal atrial fibrillation (AF), in whom sustained (greater than 30 seconds) AF was induced by atrial stimulation with up to 2 extrastimuli and paced rates between 100 and 180 beats/min. In 7 patients AF persisted despite the application of cibenzoline, and in 8 patients the induction of sustained AF was prevented by cibenzoline. Intraatrial conduction time, flutter cycle length and shortest ventricular cycle length during AF were increased by cibenzoline (p less than or equal to 0.01). Sinus cycle length was decreased (p less than or equal to 0.05), whereas sinus node recovery time remained unchanged. The effective refractory period of the right atrium was not significantly affected. Eight patients with frequent episodes of paroxysmal AF received oral cibenzoline for control of paroxysmal AF irrespective of the efficacy of intravenous cibenzoline. Prevention of stimulation-induced AF predicted successful treatment of paroxysmal AF (p = 0.018). Cibenzoline could be effective in the treatment of atrial arrhythmias, and selection of an antiarrhythmic therapy for recurrent AF seems to be useful.

Oxidation of the indole nucleus of 5-hydroxytryptamine and formation of dimers in the presence of peroxidase and H2O2

5-Hydroxytryptamine (5-HT) is rapidly oxidized in the presence of peroxidase and H2O2. The major reaction product was isolated by gel chromatography and analyzed by mass spectroscopy. It is a 5-HT dimer formed under abstraction of two protons, most likely by the reaction at the C(4) position of two phenoxyradicals of 5-HT. In the presence of 5-HT an increased H2O2-consumption and a dose dependent reduction of the formation of reactive oxygen metabolites during H2O2 degradation was observed. The pattern of 5-HT reaction products separated by TLC was dependent on the H2O2 concentrations used. In the presence of albumen, plasma or tissue homogenates, massive binding of the 5-HT oxidation products to proteins was observed.

Effect of nicardipine on renal sodium handling in normotensive insulin-dependent diabetics and controls

In 12 newly diagnosed normotensive insulin-dependent diabetics and eight controls, we compared the effects of acute nicardipine administration on renal haemodynamics and segmental tubular movement of sodium assessed as by lithium clearances. Both in the controls and the insulin-dependent diabetics, nicardipine induced similar haemodynamic changes, including a mild decrease in mean arterial pressure and renal vascular resistance, whereas the glomerular filtration, renal plasma flow and filtration fraction were unchanged. Despite a fall in blood pressure, nicardipine exerted a marked natriuretic effect in both groups, which appears to have been primarily due to a decrease in distal reabsorption and, to a lesser extent, in proximal reabsorption.

[Diagnostic imaging of pancreatic cancer]

Despite the multitude of the imaging procedures which are nowadays at our disposal the diagnostics of the carcinoma of the pancreas and particularly of the early carcinoma is now as ever difficult. On the basis of a multicentric team study about the diagnostic course in 62 patients with diagnosed carcinoma of the pancreas we conclude to an effective diagnostic proceeding. Hereby a broad use of the ultrasound diagnostics is to be demanded and the bioptic clarification of focal findings is early to be carried out. With the help of the serial CT the differentiation between chronic pancreatitis and carcinoma of the pancreas finds particular consideration, it was successful with a reliability of 84%.

Further evidence for a two-step model of glucose-transport regulation. Inositol phosphate-oligosaccharides regulate glucose-carrier activity

The insulin effect on glucose uptake is not sufficiently explained by a simple glucose-carrier translocation model. Recent studies rather suggest a two-step model of carrier translocation and carrier activation. We used several pharmacological tools to characterize the proposed model further. We found that inositol phosphate (IP)-oligosaccharides isolated from the drug Actovegin, as well as the alkaloid vinblastine, show a partial insulin-like effect on glucose-transport activity of fat-cells (3-O-methylglucose uptake, expressed as % of equilibrium value per 4 s: basal 5.8%, insulin 59%, IP-oligosaccharides 30%, vinblastine 29%) without inducing carrier translocation. On the other hand, two newly developed anti-diabetic compounds (alpha-activated carbonic acids, BM 130795 and BM 13907) induced carrier translocation to the same extent as insulin and phorbol esters [cytochalasin-B-binding sites in plasma membranes: basal 5 pmol/mg of protein, insulin 13 pmol/mg of protein, TPA (12-O-tetradecanoylphorbol 13-acetate) 11.8 pmol/mg of protein, BM 130795 10.8 pmol/mg of protein], but produce also only 40-50% of the insulin effect on glucose-transport activity (basal 5.8%, insulin 59%, TPA 23%, BM 130795 35%). Almost the full insulin effect was mimicked by a combination of phorbol esters and IP-oligosaccharides (basal 7%, insulin 50%, IP-oligosaccharides 30%, TPA 23%, IP-oligosaccharides + TPA 45%). None of these substances stimulated insulin-receptor kinase in vitro or in vivo, suggesting a post-kinase site of action. The data confirm the following aspects of the proposed model: (1) carrier translocation and carrier activation are two independently regulated processes; (2) the full insulin effect is mimicked only by a simultaneous stimulation of carrier translocation and intrinsic carrier activity, suggesting that insulin acts through a synergism of both mechanisms; (3) IP-oligosaccharides might be involved in the transmission of a stimulatory signal on carrier activity.

[Current aspects of giardiasis]

Modern epidemiological, clinical, diagnostic and therapeutic aspects of giardiasis are described.

[Dangers due to smoking and passive smoking]

Smoking has become the most important single cause of illness and death. Since the rate of cure for the most frequent types of organ cancers is still very poor with little chance of improvement in the foreseeable future, it has become necessary to put more emphasis on cancer prevention. The same holds true for the dangers of passive smoking, which have now been confirmed by all the representative scientific bodies at home and abroad. Legal protection of nonsmokers in the workplace is long overdue. The irresponsible inactivity on the part of our government with regard to smoking and passive smoking has been sharply denounced, since it has become obvious that neither health education and information nor appeals to the public can bring about a change in the situation, but only the implementation of a whole catalog of measures, including adequate legislation.

Antagonists of luteinizing hormone releasing hormone bind to rat mast cells and induce histamine release

It was reported previously that administration of certain synthetic antagonists of LHRH to rats produced allergy-like symptoms that were attributed to their histamine releasing action. In the present study the interaction of LHRH analogs with rat peritoneal mast cells was investigated in vitro. Potent antagonists of LHRH showed strong in vitro histamine releasing activity from rat peritoneal mast cells. Membrane preparations of rat pituitary glands showed specific binding of radioiodinated LHRH antagonist as well as LHRH agonist. However, rat peritoneal mast cells and membrane preparations from those cells bound antagonist but not the agonist. Furthermore, the LHRH antagonist did not bind to membranes prepared from tissues such as prostate, liver, kidney, and brain. Competitive displacement curves of the [125I]-antagonist with different LHRH analogs showed that the ability of the analogs to compete for binding sites on mast cells was related to their histamine releasing activity. We conclude that histamine release from rat mast cells induced by LHRH analogs is mediated by specific binding of the active peptides to cell membranes. Furthermore, using rat mast cells, the binding assay in conjunction with histamine releasing assay may be utilized to predict the in vivo histamine releasing potential of new LHRH peptides which are of clinical importance.

Effectiveness of IUDs: a review

Large, multicenter, randomized trials of IUDs conducted between 1970 and 1986 encompass more than 50,000 woman-years of experience in the two-year interval following device insertion. Taken singly and collectively, these trials demonstrate that IUD failure rates are strongly affected by the age of participants, notably by the proportion of women under age 25 admitted to the studies. Individual trials and overall comparisons indicate further that: 1. Non-medicated devices such as the Mahua steel ring and Lippes loop D have pregnancy rates above 2 per 100 woman-years. 2. The first approved copper IUDs, the Copper 7 and the TCu 200, do not markedly differ in pregnancy rates from standard plastic devices with rates significantly above 2 per 100 woman-years. 3. Five more recent, widely used copper IUDs have had failure rates significantly below 2 per 100 woman-years in multicenter trials. The point estimate of the failure rate was less than 1 pregnancy per 100 woman-years for three of these IUDs. One copper-bearing device had a failure rate significantly below 1 per 100 woman-years. 4. Devices releasing either 25 mcg/day of progesterone or 2 mcg/day of levonorgestrel have had significantly higher failure rates than the more effective copper-releasing IUDs; however, devices releasing 20 mcg/day of levonorgestrel appear at least as effective as the most effective copper IUDs. Long-term IUD failure rates derived from straight assignment as well as randomized trials indicate 4-year gross cumulative failure rates do not exceed 10 per 100 for any of the standard copper devices or the Lippes loop D. Point estimates of the four-year gross cumulative pregnancy rates have been below 5 per 100 users in studies of the TCu 220C, the Nova T, the TCu 380A, and the MLCu 375.

[Smoking damages male fertility]

It is concluded from a survey on the world literature: Smoking damages the male fertility. Smoker should therefore stop the smoking not only in respect to their own health but from sense of responsibility for the future generation too. The most important reasons for this conclusions are: Tobacco smoke contains numerous mutagenic substances. They reach the male gonads via the blood. They show their mutagenic action here openly much more stronger than on egg-cells because the spermatogenesis continues over the whole male reproductive period whereas the formation of eggs is already completed in the fetal phase. The majority of studies indicates to a damaging effect also on the number and/or the motility and morphology of spermatozoa by strong smoking during a longer time. Especially smoking husbands with infertile marriages the urgent advice therefore should be given to stop smoking. Weighty epidemiological and experimental results suggest a teratogenic action in the offspring by smoking of fathers too - independently for the smoking customs of the mother. A verification and extension of these results are very desirable.

The glutathione redox cycle as a defense system against hydrogen-peroxide-induced prostanoid formation and vasoconstriction in rabbit lungs

Leukocyte-derived oxidants have been described as causing vasoconstriction and edema formation in isolated lungs. In the present study, dose-dependent and reversible pressor responses were achieved reproducibly by injection of hydrogen peroxide (H2O2) into the pulmonary artery of blood-free, perfused, isolated rabbit lungs in a dose-dependent manner. The pressor responses were accompanied by an instantaneous release of thromboxane A2 and a more delayed but quantitatively larger release of prostaglandin I2 into the recirculating perfusion fluid. There was no release of potassium or LDH, indicating the absence of overt cell damage. The H2O2-induced pressor responses were blocked by indomethacin (cyclooxygenase inhibitor), imidazole (inhibitor of thromboxane synthetase), mepacrine (phospholipase inhibitor), and W7 and trifluoperazine (agents that interfere with calcium-calmodulin function). Treatment with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) dose-dependently inhibited the lung glutathione reductase activity and augmented the metabolic (prostanoid release) and functional (vasoconstriction) responsiveness of the pulmonary vascular bed to H2O2. Application of 1-(2-chloroethyl)-1-nitrosourea (CCNU), a control to BCNU, and inhibition of catalase activity by aminotriazole did not increase the sensitivity to externally applied H2O2. We conclude that calcium-calmodium function and thromboxane generation may be involved in the pulmonary vasoconstrictive response to H2O2 and that the lung glutathione redox cycle is active in limiting the responsiveness of the pulmonary vascular bed to externally generated H2O2.

Species differences in the sensitivity to GnRH analogs

The effects of several GnRH agonists and antagonists with high biological activity, have been investigated in rats, mice, rabbits and monkeys. Striking differences exist in the response of different species to the antigonadal and antipituitary effects of these peptides. Of all the animals studied, the rat is the most sensitive. The magnitude of the response to GnRH agonists seems to depend on the sensitivity of the pituitary and the presence of GnRH receptors in the target organs. Findings from animal models require careful interpretation before predictions can be made regarding their possible effects in the human.

Ovulation inhibition in the pregnant mare's serum gonadotropin-treated immature rat: a bioassay for luteinizing hormone-releasing hormone antagonists

A convenient method for evaluating the biological activity of luteinizing hormone-releasing hormone (LHRH) antagonists was devised. Pregnant mare's serum gonadotropin (PMSG) treatment of immature rats is known to stimulate follicular growth and estrogen production, that in turn stimulates the release of LHRH which triggers an ovulatory discharge of luteinizing hormone (LH) from the pituitary. The present bioassay of the antagonists is based on the inhibition of ovulation in the PMSG-treated rats. Twenty-eight-day-old Sprague Dawley rats maintained under a light period of 12 h/day (lights on at 0630 h) were given 10 IU of PMSG s.c. at 0930 h. On Day 30 of age the antagonist was given s.c. at 1430 h. The rats were killed on the following morning and the oviducts examined for the presence of ova. In addition, the antagonists were compared in their ability to inhibit serum testosterone levels in adult male rats. In the PMSG-treated rats the order of ovulation-inhibiting potency of the following antagonists was: [Ac-D-NAL(2)1,4FD-Phe2,D-Trp3,D-Arg6]-LHRH (LHRH-1) greater than [Ac-delta 3 Pro1,4FD-Phe2,D-NAL(2)3.6]-LHRH (LHRH-2) greater than [Ac-delta 3 Pro1,4FD-Phe2,D-Trp3,6]-LHRH (LHRH-3). The order of potency was confirmed by their antitesticular effects in adult male rats.

Evolutionary relationship between Tn21-like elements and pBP201, a plasmid from Klebsiella pneumoniae mediating resistance to gentamicin and eight other drugs

We have characterized pBP201 one of the plasmids from a collection of 46 strains producing adenylyltransferase ANT(2") (Schmidt 1984). It confers resistance to sulphonamides and produces aminoglycoside adenylyltransferases AAD(3") and ANT(2") and beta-lactamase TEM-1. Plasmid pBP201 has a size of 24.8 kilobases (kb) and contains TnA and a Tn21-related element, Tn4000 delta, with deletions in mer and the termini and a substitution at tnpR. In complementation assays with transposition-deficient mutants of Tn21 the element in pBP201 appears to be TnpA+ but TnpR-. It represents a naturally occurring defective transposon. The sequence organization of pBP201 has been compared with that of Tn21-related elements such as Tn2410, Tn2603, Tn2424, Tn1696, and Tn4000. In these transposons the integration sites of resistance genes cat, bla, aacA, aacC or aadB have been identified at two preferential locations; these are at the termini of the streptomycin resistance gene aadA. Two additional sites have been localized in the Tn21 backbone to the right of the mer operon and at res (internal resolution site) and are probably involved in the evolution of these elements. Based on these results a model for the possible genealogy of class II transposons is presented.

The role of insertions, deletions, and substitutions in the evolution of R6 related plasmids encoding aminoglycoside transferase ANT-(2")

In 7% of gram-negative bacteria resistance to gentamicin is mainly mediated by plasmid-encoded aminoglycoside transferase ANT-(2"). The genome organization of 15 aadB plasmids (42-110 kb) was analyzed by restriction and hybridization techniques. They appeared to be IncFII-like replicons but were distinct from R6 by virtue of small substitutions in the transfer region. Aminoglycoside resistance genes aadB and aadA were located on Tn21 related elements. Only one of them was able to transpose its resistance genes mer sul aadA and aadB ( Tn4000 ), the other elements were naturally occurring defective transposons. In some of these structures deletions were identified at the termini, at sul, aadA , mer or transposition function--insertions adjacent to aadA or mer. The mode of these rearrangements and their site-specificity were considered with respect to the evolution of the Tn21 transposon family.

Species differences in the sensitivity to the antitesticular effects of [Ac-D-NAL(2)1, 4FD-Phe2, D-Trp3,D-Arg6]-LHRH, a potent LHRH antagonist

The antigonadal effects of [Ac-D-NAL(2)1, 4FD-Phe2, D-TRP3, D-Arg6]-LHRH (LHRH-A), a potent antagonist of LHRH, were investigated in rats and rabbits. Rats and rabbits were given LHRH-A (1250 micrograms/kg) daily for 15 days. Some animals were killed on day 16 (24 h after the last treatment) while others were mated. In the male rats serum LH and testosterone levels as well as the weights of sexual organs were significantly reduced. Mating behavior and fertility that were suppressed by the end of treatment returned to normal by 7 weeks after last treatment. In contrast to rats, the testicular function and fertility of rabbits appeared unaffected by LHRH-A treatment. The difference in the response between rats and rabbits led us to compare the response of rats and mice. Male rats and mice were given LHRH-A (1450 micrograms/kg) daily for 5 days and killed on day 6. In rats LHRH-A caused a 93% decrease in serum T and 88% decrease in in vitro testicular T production. In mice, however, the Leydig cell function remained unaffected when examined 24 h after the last dose of LHRH-A. To explain the differences between the effects of LHRH-A on rats, rabbits and mice, the acute effect of this peptide on serum T levels was investigated in these species. Administration of a single dose of LHRH-A (1250 micrograms/kg) led to a rapid decrease in serum T that was sustained for 24 h in rats. In rabbits and mice, however, the same dose of LHRH-A caused only a transient decrease in serum T. Male rhesus monkeys treated with LHRH-A (1000 micrograms/kg) also showed a transient decrease in serum T concentrations. It is concluded that there are considerable species differences in the sensitivity to the antigonadal effects of LHRH-A.

[Ac-D-NAL(2)1,4FD-Phe2,D-Trp3,D-Arg6]-LHRH, a potent antagonist of LHRH, produces transient edema and behavioral changes in rats

Acute toxicity studies of [Ac-D-NAL(2)1,4FD-Phe2,D-Trp3,D-Arg6]-LHRH (LHRH-A), a potent antagonist of LHRH were performed. Subcutaneous administration of this peptide to rats induced transient edema of the face and extremities. This effect was maximal 3-5 h after peptide administration and subsided by 24 h. These effects were not seen with an LHRH agonist or two other antagonists. This side effects of LHRH-A was peculiar to rats and not observed in mice, rabbits and rhesus monkeys. Intravenous administration led within minutes to depression of spontaneous activity in rats and monkeys. We conclude that some LHRH antagonists produce species specific effects on vascular permeability and spontaneous activity.

Transposition of a gene encoding OXA-2 beta-lactamase

A bla gene encoding OXA-2 beta-lactamase has been transposed from the Salmonella typhimurium R plasmid R1767. This transposable element which was designated Tn2410 encoded sulphonamide and mercury resistance in addition to the bla gene. It had a size of 18.5 kb and appeared to be flanked by small inverted repeats. Restriction enzyme analysis resulted in a detailed map of Tn2410, which showed a high degree of similarity with the published map of Tn2603, a transposon encoding OXA-1 beta-lactamase. The ampicillin and sulphonamide resistance genes on Tn2410 were mapped in a cluster on the region between the centre and the righ end of the map.

Characterization of Tn2411 and Tn2410, two transposons derived from R-plasmid R1767 and related to Tn2603 and Tn21

Two transposable elements, Tn2410 and Tn2411, were isolated from Salmonella typhimurium R-factor R1767. They have sizes of 18.5 and 18.0 kilobases, respectively. Tn2411 mediates resistance to streptomycin, sulfonamides, and mercury. In Tn2410, the streptomycin resistance gene was replaced by a gene coding for the production of the beta-lactamase OXA-2, which is responsible for ampicillin resistance. Physical and functional maps of both transposons were compared with those of Tn21, Tn4, and Tn2603. From these data it appeared that Tn21 could be an ancestral transposon from which Tn2411, Tn2410, Tn2603, and Tn4 were evolved by the addition or deletion of small DNA segments.