[Ischemia-reperfusion--a universal mechanism of pathogenesis of critical states in emergency surgery].

On the basis of literature data and personal investigations the authors discuss the questions of pathogenesis of critical states in sepsis and polytrauma taken as an example.

[Specific changes of the thrombocyte aggregation function in acute pancreatitis].

On the basis of investigations of thrombocyte aggregation in 126 patients with acute pancreatitis it was shown that independent of the severity of the pancreatitis the aggregation function of thrombocytes decreased. The effective treatment resulted in its normalization not earlier than within 15 days.

[The hemostasis system indices after operations of spleen trauma].

The authors have studied changes of the hemostasis system in 85 patients operated on the traumatized spleen, followed up from 1 through 15 years after operation. It was established that organ-saving operations and autolientransplantation fail to result in substantial changes in indices of the hemostasis system, while after spleenectomy there were pronounced shifts.

D1-class dopamine receptor involvement in the behavioral recovery from prefrontal cortical injury.

Following unilateral aspiration of the left medial agranular cortex (AGm) region of prefrontal cortex, rats demonstrate contralateral neglect, characterized by a failure to orient to visual, tactile and auditory stimuli presented on the contralateral body side. While dopamine (DA) has been implicated in cortical neglect and its recovery, this study specifically examined D1-class DA receptors for their involvement in spontaneous recovery from neglect caused by AGm ablation. In the first experiment, left AGm-ablated rats demonstrated severe neglect of contralateral stimuli of each modality which spontaneously recovered over a period of several weeks. Recovered rats were given 7.0 micrograms/kg (s.c.) of the D1-selective antagonist SCH 23390. SCH 23390 reinstated severe neglect of contralateral stimuli, yet had no effect on orientation to ipsilateral stimuli. The same dose had no effect on the orientation behavior of controls. In a second experiment, D1 receptor characteristics were quantified via binding of [3H]SCH 23390 to tissue homogenates of the caudate-putamen of recovered AGm-ablated rats. Numbers and affinities of striatal D1 receptors of rats with unilateral AGm ablations did not differ between hemispheres or from values obtained from lesioned controls. Considered together, these findings indicate that recovery from neglect produced by cortical injury is associated with an increased dependence on D1-class receptor-mediated events, and that this increased dependence is unlikely to be mediated through changes in D1-class receptor numbers or affinities within caudate-putamen.

Morphology and physiologic responsiveness of cultured rabbit lacrimal acini.

PURPOSE: To assess the morphology and physiologic response of intact rabbit lacrimal acini maintained in culture for as long as 14 days and to compare the characteristics of the cultured acini with untreated fresh lacrimal gland, incubated lacrimal tissue slices, and freshly isolated acini. METHODS: Acini were obtained by enzymatic digestion of lacrimal glands of adults male New Zealand white rabbits and cultured for as long as 14 days on Matrigel-coated inserts in DMEM-F12. Untreated fresh lacrimal gland, incubated lacrimal tissue slices, freshly isolated acini, and intact cultured acini were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Maintenance of physiologic responsiveness of the cultured acini was assessed by the comparison of the release of protein in response to muscarinic cholinergic, alpha 1- and beta-adrenergic, and peptidergic stimulation of the cultured acini with the secretory response of incubated tissue slices. RESULTS: As examined by TEM, the ultrastructure of intact acini cultured for 3 and 7 days was notably similar to fresh tissue and incubated tissue slices. Recovery of the cultured acini from perturbations induced by the digestion procedure resulted in acini that were firmly attached to the filter supports and that exhibited histotypic acinar morphology, including lumenal microvilli, apically situated secretory granules and junctional complexes, lateral desmosomes, and appropriate secretory organelles. Secretory granules and associated organelles also were prominent in 14-day cultures; however, by day 14, as visualized by SEM, the acini had flattened. TEM of acini at this time showed that they had lost much of their acinar organization and cellular polarization. Outgrowths composed of acinar cells could be observed by day 7 by both TEM and SEM, and SEM demonstrated non-acinar cells growing on the filter surface in 14-day cultures. The morphologic and physiologic response of the acinar cells to autonomic agonists was similar in incubated tissue slices and cultured acini. Morphologically, acinar cells in both preparations responded to cholinergic stimulation by releasing secretory granules, resulting in honeycombed regions in the cell. Assay of secreted protein in response to cholinergic, alpha 1- and beta-adrenergic, and peptidergic stimulation indicated that 3-day cultures of acini retain the response to carbachol, phenylephrine, and vasoactive intestinal peptide. However, the response to isoproterenol is diminished when compared with incubated tissue slices. CONCLUSIONS: Under the conditions described, cultures of intact lacrimal acini from New Zealand white rabbits maintain histotypic morphology and physiologic responsiveness similar to fresh lacrimal gland and incubated tissue slices. Culture of the acini affords a useful alternative for the study of chronic, as well as acute, effects of neurotransmitters, neuropeptides, hormones, and cytokines on the structure and function of the gland.

Histochemical distribution of carbonic anhydrase in rat and rabbit lacrimal gland.

PURPOSE: The purpose of this study was to examine the histochemical distribution of carbonic anhydrase (CA) in lacrimal glands from rats and rabbits; and to determine if age- and/or sex-related differences exist in the amount and distribution of CA in the rat lacrimal gland. METHODS: Lacrimal glands from young (3-12 wk) and aged (2-2.5 yr), male and female F344 rats and male rabbits were fixed in 1% paraformaldehyde and embedded in glycolmethacrylate. CA histochemistry was performed on 2-microns sections. The distribution of CA activity was determined by morphometric analysis. RESULTS: In rat lacrimal gland, CA activity was distributed in a discontinuous, mosaic fashion among the acinar cells. In tissue from young males and females as well as from aged females, about 10% of the acinar tissue displayed CA activity. Significantly more activity was present in tissue from aged male rats. CA was present in the ductal lumina, suggesting that it is a secretory product of the acinar cells. In rabbits, CA activity was associated with the basolateral membranes of the terminal acinar cells only. CONCLUSIONS: In rat, the presence of CA activity in certain acinar cells and in ductal lumina suggests that CA is actively secreted by the lacrimal gland. An age-related increase in the amount of CA activity in the male glands exists that may be under gender-specific hormonal influences. In the rabbit lacrimal gland, the membrane-associated CA found uniquely with the terminal acinar cells suggests that these cells have special transport functions associated with the primary secretion of lacrimal fluid.

Structure and function of non-enzymatically dissociated lacrimal gland acini.

Lacrimal gland acini were isolated utilizing a non-enzymatic dissociation procedure. This method resulted in the rapid isolation of an enriched population of acini from rat lacrimal gland with a complete absence of interlobular and rare occurrence of intralobular duct epithelium. The isolated acini had high viability and retained good histological organization. Alkaline phosphatase activity was present in the myoepithelial cells and capillaries associated with the periphery of the acini, indicating a relatively undisturbed basal surface. Secretion of peroxidase by the isolated acini in response to cholinergic and alpha-adrenergic stimulation indicated that the cell surface receptors in this preparation were retained and were physiologically functional. Thus, we report a dissociation protocol that eliminates enzymatic digestion, but results in a relatively enriched acinar preparation that is appropriate for the assessment of cellular biochemistry and physiology of lacrimal exocrine function of the acini.

Peroxidase secretion by lacrimal glands from juvenile F344 rats.

Secretion of peroxidase by rat lacrimal glands is generally acknowledged to be greater in juvenile rats than in adults. However, this phenomenon has not been so well documented in lacrimal glands as other age-related changes have been. Therefore, we studied lacrimal protein and peroxidase secretion in response to muscarinic cholinergic and alpha-adrenergic stimulation of glands from 35- to 90-day-old male F344 rats. Lacrimal tissue fragments were incubated in perifusion chambers, and secretion of protein and peroxidase was measured in response to stimulation by carbachol or phenylephrine. There was a negative first-order correlation between total protein secretion and age. Dose-response curves showed that at the highest doses there was a small but significant change in protein secretion. Secretion of lacrimal peroxidase in response to carbachol and phenylephrine changed significantly with increasing age. The tissue content of peroxidase was diminished by about 25% during this period, but that decrease alone was not sufficient to explain the changes in secretory responsiveness. The decrease of peroxidase secretion elicited by phenylephrine had both first- and second-order components in its correlation with age between 35 and 90 days. Dose-response curves for 5-week (35-41-day)- and 12-week (84-90-day)-old tissue showed that the maximum secretion of peroxidase was reduced by about 50%, but with no apparent shift in the dose-response curve.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic hormone stimulation of lacrimal peroxidase secretion.

The effect of adrenocorticotropic hormone (ACTH) on secretion of lacrimal gland peroxidase was studied using an in vitro perifusion technique. The peptide stimulated a dose-dependent (1 nM to 100 nM) release of peroxidase, with the maximum level of secretion induced by 20 nM ACTH. Secretion in the presence of submaximal ACTH was potentiated with either 100 microM iso-butylmethylxanthine or 0.3 microM carbachol. In contrast, the combination of ACTH and phenylephrine was additive. Time-dependence studies demonstrated that the stimulation of peroxidase release by ACTH, as with other cyclic adenosine monophosphate mediated secretagogues, showed a latency in reaching the maximum rate which was not evident with either cholinergic or alpha-adrenergic stimulation. Furthermore, where potentiation of the response to ACTH occurred, the time course was distinctly altered from that obtained with either ACTH or the potentiating agonist alone. The data suggest that lacrimal gland function is regulated by a multiple system of neurotransmitters and (or) neuromodulators that involves the activation of peptidergic as well as cholinergic and alpha-adrenergic receptors.

Sympathomimetic protein secretion by young and aged lacrimal gland.

The diminished basal tear flow in aged individuals is associated with lymphocytic infiltrations and atrophy of the lacrimal ducts and acini. We have investigated the age-related physiological changes to sympathomimetic stimulation of lacrimal tissue from F344 rats to determine if the responses are uniformly diminished as would be expected by glandular atrophy. The quantitative and temporal pattern of protein and peroxidase secretion by lacrimal gland fragments from young (4 month) and aged (24 month) F344 male rats was examined in a perifusion system. Upon stimulation of tissue from young animals with 0.01 mM phenylephrine for 40 min, secretion above baseline levels of protein was 570.8 micrograms/g tissue and of peroxidase was 45.2 delta A X min-1/g tissue. The response of the aged tissue to phenylephrine was not significantly different from that of the young tissue. beta-adrenergic stimulation by isoproterenol (0.01 mM) evoked only a modest secretion of protein and no consistently measurable peroxidase from young tissue. IBMX alone and in combination with isoproterenol (0.1 mM and 0.01 mM respectively) evoked a large secretion of protein, 1345.7 micrograms/g tissue, and a modest secretion of peroxidase, 9.5 delta A X min-1/g tissue by young tissue. The aged tissue, upon stimulation with the combination of IBMX and isoproterenol, secreted significantly less protein and peroxidase than the young tissue. In separate experiments, the production of cAMP was measured. In young tissue, isoproterenol did not cause a measurable increase of intracellular cAMP. IBMX caused a 2-3 fold increase in cellular cAMP which was not increased further by addition of isoproterenol.(ABSTRACT TRUNCATED AT 250 WORDS)

Lacrimal protein secretion: comparison of young and old rats.

The in vitro protein secretory response of lacrimal glands from healthy 4- and 24-month-old F344 rats was measured. Tissue fragments were incubated in a 0.2 ml perifusion chamber and stimulated to secrete protein by a 4-min bolus of 0.01 mM carbachol. Fractions of the perifusate were collected and assayed for protein concentration and peroxidase activity. The response to carbachol was a well-defined peak of secreted protein that included peroxidase. The response was inhibited by 1.0 microM atropine. No differences were found between the responses of male and female glands. The peak of protein secretion by the young glands contained 263.9 +/- 71.8 micrograms g tissue-1 compared to 175.4 +/- 56.5 micrograms g tissue-1 for the old glands (P less than 0.005). While the mean activity of the secreted peroxidase was similar in the two age groups, the aged glands were significantly more variable in their response. The F344 rat may provide a useful model for studying the normal age-dependent changes that occur in lacrimal gland.

Autonomic control of lacrimal protein secretion.

The ability of cholinergic and adrenergic agonists to initiate protein secretion by in vitro slices of rabbit lacrimal gland was examined. The adrenergic response was not inhibited by atropine but was partially inhibited by propranolol and phentolamine. This indicates the presence of both alpha- and beta-adrenergic receptors and their association with the protein secretory response. The cholinergic response was inhibited completely by the muscarinic antagonist atropine. Additionally, the adrenergic antagonists, propranolol and phentolamine, inhibited approximately 70% and 40%, respectively, of the cholinergic response. Dose-response curves obtained for carbachol and isoproterenol indicated that the maximum response to carbachol is greater than that to isoproterenol but that the threshold for response to isoproterenol is much lower than that to carbachol. Additionally, carbachol and isoproterenol acted synergistically in promoting protein secretion. A hypothesis for the regulation of lacrimal gland function is proposed which takes into account the autonomic effects on electrolyte transport and tear flow rates reported by others as well as autonomic control of protein secretion reported in this paper.

Beta-adrenergic receptors in ciliary processes of the rabbit.

Identification and characterization of beta-adrenergic receptors were attempted in particulate membrane fractions derived from isolated ciliary processes (CP) of rabbit eyes. High-affinity binding sites for 125I-hydroxybenzylpindolol (125I-HYP), a beta-adrenergic antagonist, were identified in particulate membrane fractions of homogenized CP that were recovered from discontinuous sucrose density gradients. Adenylate cyclase activity was recovered in the same fraction as the 125I-HYP binding sites. The dissociation constant of 125I-HYP for the high affinity site is 0.25 nM, with a minimum capacity of about 35 fmol/mg of protein. Adrenergic agonists and antagonists, including timolol, 1-alprenolol, d,1-propranolol, 1-isoproterenol, 1-epinephrine, and phentolamine, were examined for their ability to displace 125I-HYP from its binding site. The results were consistent with the identification of the high-affinity 125I-HYP binding sites as beta-adrenergic receptors. This is the first report which identifies by ligand binding techniques beta-adrenergic receptors in CP exclusive of iridial or other uveal tissue and supports the possibility of direct action of beta-adrenergic agents on the formation of aqueous humor.

Apneic spells associated with timolol therapy in a neonate.

A 2-week-old premature child with congenital glaucoma secondary to anterior cleavage syndrome was treated with timolol maleate and cyclocryotherapy. The patient had apneic spells of up to 30 seconds that stopped soon after timolol maleate therapy was discontinued. No apnea was seen before timolol maleate administration, and no further spells were noted after subsequent cyclocryotherapy without timolol maleate treatment. Possible central nervous system toxicity of timol maleate or its metabolic by-products in neonates with immature blood-brain barriers was noted.

Influences on the density of beta-adrenergic receptors in the cornea and iris--ciliary body of the rabbit.

By measurement of the specific binding of 3H-dihydroalprenolol, the densities of beta-adrenergic receptors on membranes prepared from homogenized corneas and iris--ciliary bodies of rabbits were studied. Sympathetic denervation, as a result of subconjunctival treatment with 6-hydroxydopamine, causes an increase in the density of beta-adrenergic receptors in membranes prepared from the ipsilateral iris--ciliary body but not the cornea. Topical treatment with epinephrine for 5 days causes a decrease in the density of beta-adrenergic receptors in membranes prepared from cornea and iris-ciliary body, whereas similar treatment with timolol causes an increase in the density of beta-adrenergic receptors. In the cornea, the decrease in receptor density that occurs following in vivo treatment with epinephrine is associated with a decreased ability to synthesize cyclic AMP, whereas the increase in receptor density that occurs following in vivo treatment with timolol is not associated with an altered ability to synthesize cyclic AMP. Our results indicate that the density of beta-adrenergic receptors in the anterior segment of the eye is inversely related to the level of adrenergic stimulation to the tissue but that the ability of a tissue to synthesize cyclic AMP does not necessarily parallel the change in receptor density.