Dormant stages and their participation in adjustment and regulation of life cycles of harvestmen (Arachnida,Opiliones)

Information on seasonal adaptations in the life cycles of harvestmen (order Opiliones) summarized in this review reveals a great diversity of these arachnids with respect to duration, voltinism, and phenology of their life cycles, as well as to the number and ontogenetic position of the dormant stages required for survival during the winter season and also for synchronizing development with seasonal climate rhythms. Most harvestmen have stenochronous development with univoltine life cycles synchronized by arrest of development in hibernating eggs or (rarely) diapausing nymphs and adults. The number and arrangement of dormant stages represent stable species-specific traits, with some rare cases of interpopulation differences (e.g., in Phalangium opilio). Eurychronous harvestmen exhibit the year-round occurrence of main ontogenetic stages which show equal abilities for either active development or quiescence (depending upon the external factors). Two alternative types of development arrest are common in univoltine opilionids: (1) diapause induced at the early stage of embryogenesis and terminated during cooling (in Opilio parietinus and eleven other species) with transformation into postdiapause quiescence; (2) cold quiescence enforced by low temperatures at the last stage of egg development just before hatching (in Phalangium opilio and four other species). In conclusion, the systems of seasonal adaptations in Opiliones are compared with those in other arachnids, insects, and crustaceans. Some promising directions in the study of seasonal adaptations in opilionid life cycles are suggested.     

Embolization of uterine arteries in gynecological patients with uterine bleeding of various etiology

Embolization of internal iliac and uterine arteries is one of the surgical treatments for hemorrhages that complicate the course of uterine myoma, cancer diseases and medical treatment-unresponsive conditions. Endovascular hemostasis was performed in 24 patients. The causes of hemorrhage were uterine myoma with intramural or submucous nodal location in 15 patients, cancer of the uterus corpus in 6 patients, cancer of the uterus cervix in 2, and uterine sarcoma with tumor grown in the adjacent organs in 1. In all cases, free Gianturco-type spirals were used for embolization of internal iliac and ulterine arteries. For better visualization and superselective catheterization of uterine arteries, a study was performed in the right or light oblique projections at an angle of 20-25 degrees. After embolization of iliac and uterine arteries, hemostasis was attained in all patients. At the same time there were no complications. Thus, embolization of uterine arteries is a safe and highly effective alternative to radical surgical intervention in patients with acute gynecological disease complicated by bleeding, which provides effective hemostasis and permits either avoidance of surgical intervention or a significant reduction in the volume of intraoperative blood loss.     

Radiation diagnosis of abdominal aortic aneurysms

Four hundred and forty seven patients with aneurysms of the abdominal aorta (AAA), including 238 patients with aneurysmal rupture, were admitted to the Research Institute of Emergency Care in 1990 to 2000. The results of studies in 225 patients (ultrasonography in 197, computed tomography in 59, and angiography in 104), including 155 patients with aneurysmal rupture were analyzed. Computed tomography (CT) has proved to be the most accurate technique in the detection and estimation of the size of aneurysms, as well as in the identification of ruptures (83.9%) and inferior to angiography (AG) in the study of involvement of the branches of the abdominal aorta. Ultrasound study (US) ranks below CT in its accuracy (US detects ruptures in 67.8%); however, US surpasses CT and AS in screening, particularly valuable at an admission unit and an intensive care unit, which permits repeated studies. AG has turned out to be the most valid method in identifying the involvement of renal and iliac arteries in aneurysm and in detecting aortocaval anastomoses; yet it is inferior to US and CT (the former revealed rupture and dissection in 18.6% of cases) in solving other diagnostic tasks. Based on the analysis, the optimal sequence of studies in the patients is US, CT, and AG.     

Regeneration of Haller's sensory organ in two species of hard ticks of the genus Haemaphysalis (Acari: Ixodidae)

A study of Haller's organ regeneration in nymphs and adults of Haemaphysalis turturis and parthenogenetic females of H. longicornis, from which the forelegs had been amputated during the previous instar, revealed structural changes in regenerated organs. The adult regenerates reestablished atavistic structural features, while the nymphal regenerates retained larval features, which is typical of regenerates of two other genera examined previously (Ixodes and Hyalomma). Data on regeneration of Haller's sensory organ testify to an ancient character of the genus, standing closely to the base of the phylogenetic tree of hard ticks.     

Indicators of cellular and humoral immunity in chronic opisthorchiasis]

Quantitative content of T- and B-lymphocytes in the peripheral blood was studied after Mendes in 30 patients suffering from chronic opisthorcosis and in 30 practically healthy persons; immunoglobulins--M, G, and A were examined after Mancini, and the presence of autoantibodies in the blood serum was studied by indirect method of mast cells degranulation. There was revealed a reduction of the T-cell count to 28.8 +/- 2.28% (normal value--52.9 +/- 3.32%) and a fall of IgM level to 163.4 +/- 16.2 (207.2 +/- 10.5 in donors) in the patients; macrophages count was almost doubled. Autoantibodies to the antigens of the liver, gastric mucosa and the gall bladder wall were revealed in 1/3 of the patients.     

Regeneration of Limbs and Sensory Organs in Ixodid Ticks (Acari,Ixodoidea, Ixodidae,and Argasidae)

We present a review of our own and literature data on reparative regeneration in ixodoid ticks (chelicerate arthropods). Ticks have a high potential for reparative regeneration and a close relationship between regeneration and development determined by similar hormonal regulatory mechanisms. These mechanisms depend on ecdysteroid hormones, which participate in the initiation of both processes, and juvenile hormones, which direct these processes either to the maintenance of larval features or to the development of nymphal and adult features. We present a detailed analysis of the regeneration of Haller's sensory organs in ixodid ticks and propose an hypothesis about the role of juvenile hormones in the modification of morphogenetic processes in this group. Furthermore, we present data on the effects of insect juvenile hormone analogs (methoprene and fenoxycarb) on the regeneration of Haller's organ, which support this hypothesis. Studies on reparative regeneration in arthropods provide a broader view of the problem of repair morphogenesis in animals.     

Ixodes rubicundus nymphs are short-day diapause-induced ticks with thermolabile sensitivity and desiccation resistance

The Karoo Paralysis tick, Ixodes rubicundus Neumann (Acari: Ixodidae), is a semi-voltine ixodid that survives stressful environmental conditions using morphogenetic diapause (eggs and engorged nymphs) and desiccation resistance. Both photoperiod and temperature influence diapause induction in the engorged nymph. Ixodes rubicundus nymphs are typical long-day photoperiodic organisms. The critical photoperiod is approximately 13.5 h light, 10.5 h dark, and they display a thermolabile response. The period between detachment and apolysis in engorged nymphs is modified by photoperiod; however, apolysis to ecdysis is not affected by photoperiod. Thus, initiation of development, but not the actual process is controlled by photoperiod. Most engorged nymphs delayed metamorphosis when exposed to short-day regimen (LD 12 : 12 h) after feeding. Nymphs exposed to pre- and post-feeding long-day regimen (LD 14 : 10 h) developed. Times for 50% of nymphs to apolyse when exposed to photoperiods of LD 14 : 10 h, 13.5 : 10.5 h, 13 : 11 h and 12 : 12 h were 28, 36, 40 and 58 days, respectively. Times for 50% of engorged nymphs to ecdyse ranged from 38 to 40 days after apolysis. Nymphs were sensitive to photoperiodic exposures before, during and after feeding. Nymphs exposed to long day (LD 14 :10 h) before and during feeding, moulted at 20 degrees C; however, most exposed to 10 degrees C followed by 20 degrees C (post-feeding) went into diapause. Both short- (10 : 14 h) and long- (14 : 10 h) day exposed engorged nymphs survived 45 days at 0% r.h. (n = 73), but diapause-destined ticks kept at 13 degrees C lost the least mass (29.5+/-9.5%, SD), while nondiapause ticks at 23 degrees C lost the most (48.7+/-8.2%, SD). Termination of diapause and transition to development probably coincides with a definite increase of water vapour uptake by engorged nymphs. Comparatively, I. rubicundus engorged nymphs are more desiccation tolerant than a North-American counterpart, Amblyomma cajennense (Fabricius) (Acari: Ixodidae), which is also semi-arid- to xeric-adapted. Diapause conveys important survival attributes that enable engorged I. rubicundus nymphs to inhabit a semi-arid environment with great temperature extremes, and to synchronize their activity periods with seasons and host utilization patterns.     

Regeneration of Haller's sensory organ in the tick, Ixodes rubicundus (Acari: Ixodidae)

A study of regeneration in nymphs and adults of the South African tick Ixodes (Afrixodes) rubicundus, from which the forelegs had been amputated during the previous instar, revealed that the structural changes in regenerated Haller's sensory organs resemble those observed in other ixodid ticks, in particular in another prostriate tick, Ixodes (Ixodes) ricinus. The adult regenerates re-establish their atavistic features in terms of the increased number of different sensilla on the distal knoll, in the anterior pit and the capsule. The nymphal regenerates, in contrast, re-establish the features of the previous instar through a reduction in the number of some sensilla on the distal knoll and in the post-capsular area. The structural changes in different compartments of the organ appear independent. The phenomenon of regenerative induction through the appearance of specific changes in Haller's organ of the contralateral non-treated foreleg is probably characteristic only of prostriate ticks. A unique modification in the regenerated Haller's organ as revealed by duplication of the Haller's organ capsule was discovered in both I. rubicundus nymphs and adult ticks.