Holliday junction resolving enzymes of archaeal viruses SIRV1 and SIRV2.

In the final stages of genetic recombination, Holliday junction resolving enzymes transform the four-way DNA intermediate into two duplex DNA molecules by introducing pairs of staggered nicks flanking the junction. This fundamental process is apparently common to cells from all three domains of life. Two cellular resolving enzymes from extremely thermophilic representatives of both kingdoms of the domain Archaea, the euryarchaeon Pyrococcus furiosus and the crenarchaeon Sulfolobus solfataricus, have been described recently. Here we report for the first time the isolation, purification and characterization of Holliday junction cleaving enzymes (Hjc) from two archaeal viruses. Both viruses, SIRV1 and SIRV2, infect Sulfolobus islandicus. Their Hjcs both consist of 121 amino acid residues (aa) differing only by 18 aa. Both proteins bind selectively to synthetic Holliday-structure analogues with an apparent dissociation constant of 25 nM. In the presence of Mg(2+) the enzymes produce identical cleavage patterns near the junction. While S. islandicus shows optimal growth at about 80 degrees C, the nucleolytic activities of recombinant SIRV2 Hjc was highest between 45 degrees C and 70 degrees C. Based on their specificity for four-way DNA structures the enzymes may play a general role in genetic recombination, DNA repair and the resolution of replicative intermediates.

Fetal gender and aggression in pregnant stumptail monkeys (Macaca arctoides).

Agonistic behaviors of pregnant female stumptail monkeys, members of a large, well-integrated group continuously living together, were studied during 480 observation hours (over 32 months). A total of 28 pregnancies of 20 females occurred, resulting in 12 male and 16 female live infants. The main finding was a significant decline in aggression, both received and performed, during the course of pregnancy. There was no clear unequivocal effect of fetal gender on aggressive behavior of the mothers-to-be.

Behavioral aspects of puberty in group-living stumptail monkeys (Macaca arctoides).

Behavioral changes before and around the time of puberty were studied in a longitudinal manner in male and female stumptail monkeys. Around the time of testicular descent (mean age: 3.3 years) males started to become more aggressive towards adult males. Within two years following testicular descent males rose in rank with the support of others and reached stable (sub)top positions in the dominance hierarchy. In the female rank-stabilization took place gradually between one year before and two years after first ovulation (mean age: 3.7 years). Copulatory activity began about two (in females) to two-and-a-half years (in males) before reproductive capacity was attained. Female copulatory activity began to rise about six months before first ovulation, when they started to copulate with adult males. In males copulatory frequency rose sharply between six and twelve months prior to testicular descent. Until a few months after testicular descent males could copulate openly in the group without interruption; from about 1 year following testicular descent virtually all copulations had to take place surreptitiously to avoid interruption by higher ranking adult males. It is postulated that this decreasing tolerance of adults may contribute to the process of peripheralization and migration of young adult males which occur in free ranging macaque groups.

Testosterone, testis size, seasonality, and behavior in group-living stumptail macaques (Macaca arctoides).

During a 28-month period, data were collected on physiological parameters and sociosexual behavior of 13 adult male members of a large mixed-sex group of stumptail macaques living in an outdoor cage. Monthly measurements of plasma testosterone, testis size, and body weight revealed no systematic seasonality. Seasonal variations did occur in branch shaking and grooming (both with low rates in winter), but not in other behaviors studied (copulation, masturbation, aggression). Dominance ranks were stable throughout the study period and were not significantly correlated with mean testosterone levels. Temporal fluctuations in behavioral frequencies did not parallel testosterone fluctuations. Interindividual differences in behavioral frequencies were often correlated with dominance rank, but not with testosterone levels.

Physiological aspects of puberty in group-living stumptail monkeys (Macaca arctoides).

Physiological changes around the time of puberty were studied in a longitudinal manner in male and female stumptail macaques. In the male, testicular descent (mean age 3.3 years) is an early sign of puberty, which coincides with onset of the pubertal spurt in body weight and testis growth and precedes the pubertal rise in plasma testosterone. In the female no clear external signs of puberty have been found. Measurements of plasma progesterone yielded proof of first ovulation (mean age 3.7 years), a late sign of puberty in primates. This event coincided with a fall in the rate of body weight growth at the end of the pubertal growth spurt. Reproductive capacity of both males (first ejaculation) and females (first conception) appears to be reached around the 4th birthday.

Blood variables in adult stumptail macaques (Macaca arctoides) living in a captive group; annual variability.

Monthly blood samples were collected for more than two years from adult stumptail macaques living in a large captive group. The social organization, feeding pattern, and food composition were stable throughout the study period. No seasonal variability was observed for any of the 30 blood variables studied. It appeared that for each variable, within-animal variance was small relative to between-animal variance. A table of means and reference ranges is presented and discussed.

Effects of early intracoronary streptokinase on infarct size estimated from cumulative enzyme release and on enzyme release rate: a randomized trial of 533 patients with acute myocardial infarction.

The effects of early intracoronary streptokinase (SK) on enzymatic infarct size and rate of enzyme release were studied in a randomized multicenter trial. A total of 533 patients with acute myocardial infarction (AMI) were allocated to either the SK treatment group (n = 269) or the conventional (control) treatment group (n = 264). Enzymatic infarct size was represented by the cumulative quantity of alpha-hydroxybutyrate dehydrogenase (HBDH) released by the heart per liter of plasma in the first 72 hours. Rate of enzyme release was represented by the ratio of HBDH quantities released in 24 hours and 72 hours. On an "intention to treat" basis, the SK group had a smaller (by 30%; p = 0.0001) median enzymatic infarct size and a higher (by 35%; p = 0.0001) median rate of enzyme release than the control group. Limitation of infarct size was less apparent in patients treated with intracoronary SK only (25%) than in patients treated with intravenous plus intracoronary SK (34%). Compared to the control group, the enzyme release rate in patients treated with intracoronary SK only was slightly less (34%) than that in patients treated with intravenous plus intracoronary SK (38%). Patients with a patent infarct-related coronary artery at acute angiography had a median infarct size which was 55% (p = 0.0001) smaller than the median infarct size of the control group, and the median rate of enzyme release was 38% (p = 0.001) higher than the median release rate of the control group. Patients with successful recanalization during intracoronary SK infusion had a median infarct size which was 31% (p = 0.002) smaller than the median infarct size of the control group and a median rate of enzyme release which was 42% (p = 0.0001) higher than the median release rate of the control group. Patients with persistent coronary occlusion in spite of thrombolytic therapy had a median infarct size which was 11% (NS) higher than the median infarct size of the control group, although the median rate of enzyme release was still 23% (p = 0.02) higher than the median release rate of the control group. It is concluded that thrombolysis in the early phase of AMI limits infarct size and that intracoronary SK treatment itself accelerates the process of enzyme release from infarcted myocardium, independent of the angiographic result.

Sexual behaviour during ovarian cycles, pregnancy and lactation in group-living stumptail macaques (Macaca arctoides).

Sexual interactions were studied in a large, well-integrated group of stumptail macaques, continuously living together. Copulations with the highest-ranking male and with young males were equally distributed over the ovarian cycle. Copulations with other adults males also occurred during all cycle phases, but were most frequent peri-ovulatory. This was most distinct in conceptive cycles. Copulatory activity continued during early pregnancy, but was virtually absent during the middle and latter part of pregnancy and during lactation. Fluctuations in copulation frequency could be attributed to fluctuations in female attractivity (as measured by directed male masturbations), but not in proceptivity (spontaneous presents) or receptivity (acceptance ratios). However, hormonal influences on attractivity could be overruled by social factors. With regard to the expression of heterosexual behaviour, stumptail macaques seem to be less hormone-dependent than other primate species studied, both in the laboratory and under more natural circumstances.

Effect of thymopentin on the mortality and immune response after an experimental herpes simplex infection in mice.

The effect of thymopentin on the mortality rate of mice treated with lethal doses (LD90) of herpes virus 2 and on the cytotoxic T cell activity after sublethal doses (LD10) of herpes virus was investigated in two series of experiments. Doses of 1, 0.1 or 0.01 ng of thymopentin per g/mouse were administered i.p. in each experiment, either 3 days before, 3 days (66 h) after, or 3 and 6 days after the herpes virus infection. The cumulative mortality rate was evaluated 10 days after the infection. Cytotoxic T cell activity was measured 3, 7 and 14 days after the infection. The 0.1-ng dose of thymopentin reduced the mortality rate to less than 50% (p = 0.0000) if it was administered 3 days before the infection. A single injection of any dose after infection did not reduce the mortality at all, while two injections of 0.1 ng reduced it by about 25% (p = 0.0038). A 1-ng dose showed a mild but significant reduction (p = 0.0313) if it was applied 3 days before the infection. The cytotoxic T cell activity was either not influenced or significantly modified (p less than 0.05), i.e. increased or decreased as compared to the control, depending on the dose and timing of thymopentin. A correlation between increased cytotoxic T cell activity and protection against mortality can be demonstrated, while no protection was observed in dose regimens where the cytotoxic T cell activity became reduced. The results are discussed in connection with earlier clinical studies in which the beneficial effect of thymopentin has been demonstrated in frequently relapsing herpes labialis and herpes genitalis patients.

Functional development of the parasympathetic innervation of the sino-auricular node in newborn rabbits, cats and guinea pigs.

The effects of supramaximal vagus nerve stimulation on heart rate were studied in newborn rabbits, cats and guinea pigs. The analysis of the stimulus-effect curve revealed that the earlier proposed relationship: log If/IO = H.f (IO is the steady state PP-interval before and If during stimulation, f is the stimulus frequency, and H the slope of the line) accurately summarizes the relation in rabbits, while with minor deviations it also holds for newborn cats and guinea pigs. Thus, the vagus effect for each nerve and animal is characterized by the slope of the line, H. In rabbits and cats the vagus effect decreased during the first postnatal week to about 1/3 and 1/5 of the initial value at birth. Guinea pigs, however, did not show such a postnatal change of the vagus effect. In comparison with rabbits and cats these animals are born at a relatively late ontogenetic stage. Therefore, we hypothesized that the decrease in vagus effect is related to the stage of development and occurs mainly before birth in this species.

Attenuation of the negative chronotropic effect of myelinated fibers by nonmyelinated fibers in the vagus nerve of the rabbit.

In the adult rabbit, both myelinated and nonmyelinated efferent fibers travel from the cervical vagus nerve to the sinoauricular node. The myelinated fibers convey the negative chronotropic effect. The influence of the nonmyelinated fibers was studied. Stimulation (4/sec) of the myelinated fibers, while the compound action potential was monitored continuously, caused a slowing of the heart rate. Subsequent activation of the non-myelinated fibers attenuated this negative chronotropic effect. Stimulation of adrenergic fibers was excluded, based on data from histochemical studies and the effects of blockade of beta- and muscarinic receptors. The lengthening of the RR interval during activation of the myelinated fibers alone was about 3.5 times larger than during activation of all fiber groups. When the conduction of the myelinated fibers was blocked (anodal block), activation of the nonmyelinated fibers did not show any effect on heart rate. It was concluded that the negative chronotropic effect is conducted via small myelinated fibers and that the nonmyelinated fibers modulate the effect of these cardiomotor fibers, without having an effect on heart rate on their own. This modulation is effected either via a presynaptic mechanism on preganglionic fibers or via an interaction with postganglionic neurons. The nonmyelinated fibers constitute a novel peripheral system to modulate heart rate.

Developmental morphometry and physiology of the rabbit vagus nerve.

The morphological and physiological features of the rabbit vagus nerve were studied at different ages after birth. The total fibre count is about 37,500 of which at birth 1-2% and in the adult animal approximately 10% are myelinated. In the postnatal period the cross-sectional area of the vagus grows to 5 times its perinatal size due to an increase of endoneural collagen, fibre growth and myelinization. The myelinization is most pronounced in the first 2 weeks after birth, axonal growth is predominant thereafter. The available data suggest that the begin of myelinization as well as the subsequent development of the myelin sheath are not dependent on axonal size. There seems to be no fundamental difference between the morphological development of the vagus and other peripheral nerves, e.g. the sciatic nerve of the rat. At birth the vagus nerve contains 2 fibre groups as can be measured from the compound action potential with conduction velocities of 11.4 and 0.9 m.s-1 respectively. Upon subsequent development the conduction velocity of these fibres increases to 31.9 and 1.2 m.s-1 in full-grown animals. THe compound action potential of the adult nerve implies 2 additional fibre groups with conduction velocities of 12.3 and 4.6 m.s-1 respectively. These two fibre populations develop gradually from 1 to 2 weeks after birth and arise probably from the slowest conducting, non-myelinated or C-fibres. It is concluded that the functional innervation of the sinoauricular node may be operational at birth as far as the cervical vagus nerve is concerned.

Hepatic disposition and biliary excretion of the organic cations thiazinamium and thiazinamium sulfoxide in rats.

The disappearance from plasma and the excretion in bile of the monoquaternary thiazinamium (administered as the iodide) and one of its polar metabolites, thiazinamium sulfoxide (also administered as the iodide), were studied in the rat after intravenous injection to obtain more information on hepatic transport mechanisms for organic cations. Both compounds exhibited an extremely rapid plasma disappearance, partly due to a rapid liver uptake. After injection of thiazinamium iodide and thiazinamium sulfoxide iodide, 36 and 47%, respectively, of the administered dose were excreted in bile during 1 hr. TLC analysis of the bile showed at least two unidentified polar metabolites in addition to thiazinamium sulfoxide and only 3.8% unchanged thiazinamium after administration of thiazinamium iodide. The same metabolites were found after injection of thiazinamium sulfoxide iodide. Urinary excretion and intestinal secretion were 18 and 12%, respectively, for thiazinamium sulfoxide iodide and 27 and 9%, respectively, of the dose for thiazinamium iodide. It is concluded that, in spite of unequal physicochemical features, thiazinamium iodide and thiazinamium sulfoxide iodide differ only slightly in hepatic uptake and metabolism.