Histophysiology of the microvascular bed in experimental trauma

1. Morphohistological changes in a focus of spinal cord trauma have a phasic character, with a period of primary lesions (5-30 min after traumatization) and a period of secondary lesions (1-23 h after traumatization). 2. Variation of transport enzyme activities in the walls of the microvessels of the traumatized spinal cord is characterized by an undulating course and by asynchrony of the peaks of Mg-dependent ATPase and alkaline phosphatase activity. 3. With reference to the rapid drop in the given enzyme activities and to progressive necrotic changes in the traumatized spinal cord, it is desirable that the cord circulation should be corrected within the first few hours after traumatization.     

Changes in the blood microcirculation in the mouth mucosa in experimental stomatitis

Aphthous lesions in the oral mucosa (OM) were simulated in dog experiments by ligation of the common bile duct. In one of the experimental groups the beta-adrenoblocker propranolol was administered 30 min before surgery. Two hours after surgery the animals manifested changes in blood microcirculation of the OM. In animals treated with propranolol, the characteristics of blood microcirculation remained within normal. It is concluded that the development of aphthous lesions is preceded by functional disorders of blood microcirculation in the OM which are probably related to alterations in the neurovascular system.     

Comparative characteristics of microcirculation disorders in the serous membrane of the uterus in intact and pregnant rats treated with oxytocin

The studies were performed on intact and pregnant rats after the administration of 10(-2) U of oxytocin. Oxytocin-induced increase in spasm duration and microvascular dilatation was noted both in intact and pregnant animals. However, in the former case spasm duration was markedly increased, while in the latter case there was an equal increase both in spasm duration and dilatation. Dilatation phase was characterized by an increase in microvessel diameter, as compared to the initial one. Maximal spasm phase after oxytocin administration in intact rats was characterized by hemostasis. In pregnant animals blood flow was delayed, with no marked spasm present. The initial level of microcirculation was restored 38-40 minutes later.     

Microcirculatory disorders in the connective tissue structures of certain organs in traumatic shock with acute hemorrhage]

The present work is a fragment of the author's complex study of replantation of an extremity in experiment. Experiments on reproduction of the model of traumatic shock with acute loss of blood under conditions of muscle relaxation proposed by Yu. V. Kiprenski were performed in 15 dogs and 10 cats. It was established that in animals dead as a result of shock there appeared severe disorders of microcirculation in tissues and organs. They were characterized by a pronounced spasm of the vessels of the arteriolar link and dilatation of the venular and lymph collectors of the microcirculation bed. Simultaneously a great number of arterio-venular anastomoses were opened through which the arterial blood was shunted partly to avoid constricted capillaries. In the vessels of the venular link of the microcirculatory bed there appeared aggregations of formed elements of blood and microemboles. In absence of specific complex therapy, as it was in our experiments, the animals die of shock within the period from 17 min to 5 hour 20 min.     

Central pool of serotonin and tail-flick latency during two phases of biphasic fever in rats

In experiments on male Wistar rats, the acute phase reaction was induced by a bolus intravenous injection of Escherichia coli lipopolysaccharide (10 microg/kg) through a silicon catheter pre-implanted into the jugular vein. The colonic and skin temperature was measured with thermocouples. Changes in nociception were assessed based on tail flick latency (TFL) in response to a noxious heat stimulus. In this work, we observed the development of biphasic fever and phasic changes in TFL, namely, hyperalgesia in the first period of the acute phase reaction and hypoalgesia in its second phase. The catabolism of serotonin increased most considerably in the initial period of the acute phase reaction in the midbrain, striatum, and rostrodorsomedial medulla (on average, by 20-25%, 35-40%, and 95-100%, respectively). In the second phase of the acute phase reaction, despite a significant increase in the serotonin content in the striatum, midbrain, and cerebellum, there were no significant changes in serotonin catabolism in these parts of the CNS, which coincided with hypoalgesia. Thus, the phasic changes in TFL and colonic temperature after initiation of the acute phase reaction were accompanied by determinate changes in the catabolism of serotonin in different brain parts.     

Dynamics of microcirculatory system recovery in the post-stress period

Twenty-four-hour immobilization or electric stimulation for 6 h were used in rats as stressors. The first stressor caused more profound and protracted disturbances in the microcirculatory system. The recovery of the microcirculation occurred in 50% of animals by day 6 and in 100% by day 14 after immobilization. The terminal blood flow recovery after 6-hour electric stimulation was seen in a day. Vascular permeability after 24-hour immobilization returned to normal in 24 h, and after 6 h of electric stimulation in 6 h. This process correlated with the morphofunctional status of mast cells and was probably phasic in nature.     

Influence of acute stress on the triiodothyronine (T3) and serotonin content of rat's immune cells

Stress caused by 48 h food and water deprivation provoked significant changes in T3 and serotonin content of lymphocytes. The concentration of these hormones decreased in the last hour of stress. However, 48 h later there was no difference between the hormone content of immune cells of stressed and control animals. Since in earlier experiments three weeks after exposed to stress a significant difference between the control and stressed animals was found, this means that an imprinting-like phenomenon happened with consequences manifested later. The most sensitive cells to acute stress are lymphocytes, however the imprinting influences all types of of the immune cells.     

The effect of bull seminal ribonuclease on spermatogenesis in the rabbit

Bull seminal ribonuclease is a very strong antigen in rabbits. In most animals the antibodies were formed after the first course of immunizations. Antibodies were of IgG immunoglobulin character. When bull seminal ribonuclease itself, and in a complex with IgG immunoglobulin fraction, was injected into rabbit testes, lower weight testes and inhibition of seminiferous epithelium development were observed for a few weeks. Similar changes were evoked by subcutaneous injections of the enzyme. During the inhibition of spermatogenesis by the enzyme no histological changes in the intertubular tissue of testes or changes in androgen concentration in the blood serum were detected.     

Distribution of mRNAS of fibrinogen polypeptides and albumin in free and membrane-bound polyribosomes and induction of alpha-fetoprotein mRNA synthesis during liver regeneration after partial hepatectomy

To study the effect of regenerative response of the liver following partial hepatectomy on the synthesis of major plasma proteins (secretory proteins), we have determined the sequence contents and the distribution of albumin and fibrinogen polypeptide mRNAs in rat liver at intervals after partial hepatectomy and sham operation. Using a quantitative technique for the isolation of polyribosomes, we demonstrated that the distribution of RNA between free and membrane-bound polyribosomal fraction was unchanged in these experiments. There was no shift in the polyribosomal population to favor free polyribosomes after partial hepatectomy. However, there was a dramatic increase (5-6-fold) of the fibrinogen polypeptide mRNA concentration during the first 24 h after resection. In contrast, the albumin mRNA concentration decreased (2-3-fold). There were no alpha-fetoprotein mRNA sequences detectable in any liver RNA fraction in these experimental animals. In sham-operated rats with intact livers, similar changes of fibrinogen polypeptide and albumin mRNA concentrations as described in regenerating liver after partial hepatectomy, were observed. These results suggest that albumin and fibrinogen synthesis after partial hepatectomy is reciprocally regulated at the mRNA level and represents a nonspecific acute phase response to surgical trauma.     

Microcirculatory disturbances following the passage of emboli in an experimental free-flap model.

Following completion of arterial repair in an experimental free-flap model, platelet emboli have been observed passing through the microcirculation downstream. The purpose of this experimental study was to observe and quantitate changes in capillary perfusion occurring subsequent to these events. The isolated rat cremaster model was used. For 6 hours subsequent to surgical injury of the main artery in this model, the number of emboli and the number of perfused capillaries downstream were counted. In eight rats having an intentional arterial wall injury, emboli were consistently seen during the first hour of reflow. In the nine control animals having no arterial injury, no emboli were seen. The presence of emboli in the cremaster muscle, resulting from the arterial injury, was associated with a significant reduction in the number of perfused capillaries. We suggest that the observed decrease in capillary perfusion was associated with microemboli that produced an adverse effect for several hours after their initial presence in the circulation.     

Effect of the time of the day when the lesion was produced on the course of mesothelial proliferation

The course of mitotic activity in the rabbit mesothelium of parietal peritoneum was studied depending upon the daytime when the lesion was produced. In the first series of experiments (I) the operation was performed from 8 to 10 a. m., and in the second series (II) - from 8 to 10 P. M. After the operation the animals were sacrifieced: one animal every 3 h during 5 days. Mitotic activity was investigated along 13 mm from the edge of the wound in flat film preparations. The data obtained were statistically treated applying approximation of the process course by the method of weighed sliding averages. The first mesothelial mitoses appeared: in the first series (I) of experiments - in 24 h, in the second series (II) of experiments - 21 h. Further, proliferation of the mesothelium appeared in different parts of the tissue with various intencity and was of wavy character. Regardless of the time when the lesion was produced, mitotic activity was the greatest in the first zone, 4.8 mm wide its maximum 33 h after the operation. The character of the regenerative process in the mesothelium depends on the circadian phase of the organism at the time of the operation, that influences the time when mitotic activity begins, its quantitative indices, the area of the tissue involving into the reaction, expressiveness of the rhythmicity of the process. During 5 days, in the II series of experiments three waves were noted, and in the I series - five waves were noted and their periods were near the diurnal.     

Morphological evaluation of the viability of silicon-lavsan tracheal prostheses

Time course of the healing process in the tracheal wall during silicon-lavsan tracheal grafting was investigated in experiments on 108 dogs with a new model of tracheal prosthesis. The formation of granulation tissue was noted as a result of postoperative inflammatory reaction in the prosthetic area. The tracheal epithelial layer adjacent to the anastomoses was hypertrophic and acquired the features of squamous epithelium. Later, after the implantation the prosthesis was surrounded by a thick fibrous capsula. In anastomoses, at tracheal tissue--implant border there was a poorly expressed inflammatory reaction, which had a local character and was compatible with 3 and more years of life in most experimental animals.     

Distribution of mRNAs of fibrinogen polypeptides and albumin in free and membrane-bound polyribosomes and induction of α-fetoprotein mRNA synthesis during liver regeneration after partial hepatectomy

To study the effect of regenerative response of the liver following partial hepatectomy on the synthesis of major plasma proteins (secretory proteins), we have determined the sequence contents and the distribution of albumin and fibrinogen polypeptide mRNAs in rat liver at intervals after partial hepatectomy and sham operation. Using a quantitative technique for the isolation of polyribosomes, we demonstrated that the distribution of RNA between free and membrane-bound polyribosomal fraction was unchanged in these experiments. There was no shift in the polyribosomal population to favor free polyribosomes after partial hepatectomy. However, there was a dramatic increase (5–6-fold) of the fibrinogen polypeptide mRNA concentration during the first 24 h after resection. In contrast, the albumin mRNA concentration decreased (2–3-fold). There were no α-fetoprotein mRNA sequences detectable in any liver RNA fraction in these experimental animals. In sham-operated rats with intact livers, similar changes of fibrinogen polypeptide and albumin mRNA concentrations as described in regenerating liver after partial hepatectomy, were observed. These results suggest that albumin and fibrinogen synthesis after partial hepatectomy is reciprocally regulated at the mRNA level and represents a nonspecific acute phase response to surgical trauma.     

Role of initial hemodynamic status and rate of blood loss replacement in postresuscitation changes in blood circulation and animal mortality]

In 43 experiments performed on narcotized dogs after 10 min clinical death induced by exsanguination, the peculiarities of postresuscitation changes in the blood circulation associated with the initial hemodynamic status, the rate of the blood loss replacements after restoration of cardiac activity, and the use of infusion therapy by albosorb (specifically processed albumin) were studied. The effect of the initial level of stroke index (SI) on the pronouncement of postresuscitation derangements in the central hemodynamics (CHD) and on the resuscitation outcome was determined. With the initial value of SI being mean, the maintenance of a moderate blood deficit (10 to 15 ml/kg) within the first hour of restoration was accompanied by an improvement in the survival rate of the animals as compared with a rapid and complete replacement of the blood. The infusion of albumin and creation of a moderate overtransfusion by the first hour post resuscitation removed the prognostic value of the initial SI.     

Mechanism of toxicity of precocene II in rat hepatocyte cultures

Precocene II was more toxic in 24 hour cultures than in 72 hour cultures of rat hepatocytes. In 24 hour cultures, there was no observable toxicity at 75 μM precocene II after exposure for 6 hours, but after 24 hours, 65% of the cells were dead. In contrast, although 794 μM killed 50% of the cells in the 72 hour cultures after a 24 hour exposure, 1 mM killed 96% of the cells within 6 hours. In both 24 and 72 hour cultures, cell death was preceded by a rapid, early loss of mitochondrial membrane potential, followed by decreases in glutathione, reduced pyridine nucleotide status, and plasma membrane Na⁺/K⁺-ATPase activity. There was also a rapid loss of ATP in the 72 hour cultures but not in the 24 hour cultures; therefore, onset of cell death may be closely linked to loss of ATP. Inhibition of cytochrome P-450 prevented the toxicity, and partially protected against the loss of membrane potential and glutathione, in 24 hour cultures but was ineffective in 72 hour cultures. Therefore, in addition to depletion of glutathione, precocene II appears to damage mitochondria and plasma membrane functions and can do so by more than one pathway. © 1996 John Wiley & Sons, Inc.     

The role of lipid metabolism disorders in the mechanism of the hepatotoxic effects of rubomycin

The phase character of the changes in the contents of lipids and phospholipids and impairment of the ratio of separate fractions in the liver mitochondria after discontinuation of rubomycin (daunorubicin) administration were studied in the time course of 35 days. The impairments were accompanied by activation of lipid peroxidation. By the end of the experiment (on the 35th day) there was noted a tendency to normalization of the indices studied.     

Relationships between muscular strength and the level of energy sources in the muscle

Relationships between muscular strength and the level of energy sources in the muscle. Acta Physiol. Pol., 1978, 29 (2): 139--151. An attempt was made to establish a relationship between the post-excercise changes in the level of anaerobic energy sources and changes in the muscular strength. The gastrocnemius muscle of Wistar rats was examined. The muscle strength was measured by the resistance tensometry. In muscle specimens ATP, CP and glycogen contents were determined. It was demonstrated that changes in the post-excersise muscle response to electric stimulus have a phasic character resembling the overcompensation curve. The percent changes in the content of anaerobic energy sources in the muscle after contractions varying in duration suggests also overcompensation the muscle content of these substances. The parallelity between the time of appearance of peak overcompensation phase in the muscle strength and in the post-exercise level of musclar ATP, CP and glycogen contents suggest a casual relationship between these changes.     

Ca-Cd interaction in the prymnesiophyte Cricosphaera elongata

Abstract. ⁴⁵Ca and ¹⁰⁹Cd uptake were followed in Criscosphaera elongata Prymnesiophyceae. In both cases, after a rapid increase for the first 5 min, the incorporation rate slowed during the hour of observation. Verapamil, a blocker of voltage-dependent slow calcium channels, inhibited ⁴⁵Ca uptake except during the first rapid phase when adsorption should predominate. Cadmium also decreased ⁴⁵Ca labelling, suggesting that the two metals are antagonistic. However, verapamil was shown to augment ¹⁰⁹Cd incorporation, contrary to what occurs in animals cells; this effect is detectable in continuous labelling as well as in pulse experiments. The data support the presence of calcium channels in the alga and suggest several processes in Cd accumulation: adsorption on peripheral envelopes and diffusion of uncharged Cd.     

Functional morphology of suprachiasmatic nuclei neurons of rat hypothalamus after the combined influence of x-irradiation and light exposure

For estimation of light radiomodification and cellular neuroadaptation of the circadian pacemarker, the morphological changes of suprachiasmatic nuclei (SCN) neurons of rat hypothalamus after 48-hours bright light exposure, the single 5 Gy whole-body X-irradiation and their combination were subjected to analysis. The dynamics of reactive and reparative changes has got a phasic character. Temporary desynchronous changes were developed in the course of the early period. Age morphological changes after X-ray and combined irradiation were discovered in the remote period. The plastic diapason of ventrolateral division (SCNv) is more considerable in comparison with dorsomedial division (SCNd). The synergism of X-irradiation and light exposure was discovered in SCNd.     

Lipoxygenase and cyclooxygenase blockade by BW755C does not prevent the secondary phase of septic pulmonary hypertension

The infusion of Group B beta hemolytic streptococci (GBS) in newborn animals generates a dual phase pulmonary hypertensive response. The initial, acute phase responds to cyclooxygenase or thromboxane inhibition, and appears to be thromboxane mediated. The second phase is characterized by a more moderate rise in pulmonary vascular resistance, accompanied by an increase in microvascular permeability. It has been speculated that this phase may be leukotriene mediated. In an attempt to clarify this, we have studied and compared the effects of the thromboxane synthetase inhibitor, Dazmegrel (DAZ), and the combined cyclooxygenase/lipoxygenase inhibitor, BW755C, on the cardiopulmonary hemodynamics of the secondary phase of GBS induced pulmonary hypertension in newborn piglets. Ten piglets were infused with GBS, and all animals developed a significant increase in pulmonary artery pressure (to 39 +/- 5 and 36 +/- 5 mmHg for DAZ and BW755C animals respectively). After one hour of GBS, either DAZ or BW755C was administered. Data were collected for another two hours following drug administration. GBS infusion was continued throughout. Both DAZ and BW755C were associated with transient, acute reductions in pulmonary artery pressure (to 22 +/- 5 and 22 +/- 8 mmHg, respectively). However, after 60 minutes, PAP again began to rise in both groups (PAP 30 +/- 5 and 30 +/- 11 mmHg respectively by 240 minutes). There were no differences between the groups at any time. These data do not support a significant role for lipoxygenase products in mediating the secondary phase of septic pulmonary hypertension.